Distributed single source coding with side information

NASA Astrophysics Data System (ADS)

Vila-Forcen, Jose E.; Koval, Oleksiy; Voloshynovskiy, Sviatoslav V.

2004-01-01

In the paper we advocate image compression technique in the scope of distributed source coding framework. The novelty of the proposed approach is twofold: classical image compression is considered from the positions of source coding with side information and, contrarily to the existing scenarios, where side information is given explicitly, side information is created based on deterministic approximation of local image features. We consider an image in the transform domain as a realization of a source with a bounded codebook of symbols where each symbol represents a particular edge shape. The codebook is image independent and plays the role of auxiliary source. Due to the partial availability of side information at both encoder and decoder we treat our problem as a modification of Berger-Flynn-Gray problem and investigate a possible gain over the solutions when side information is either unavailable or available only at decoder. Finally, we present a practical compression algorithm for passport photo images based on our concept that demonstrates the superior performance in very low bit rate regime.

Code Analysis and Refactoring with Clang Tools, Version 0.1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kelley, Timothy M.

2016-12-23

Code Analysis and Refactoring with Clang Tools is a small set of example code that demonstrates techniques for applying tools distributed with the open source Clang compiler. Examples include analyzing where variables are used and replacing old data structures with standard structures.

Bit-wise arithmetic coding for data compression

NASA Technical Reports Server (NTRS)

Kiely, A. B.

1994-01-01

This article examines the problem of compressing a uniformly quantized independent and identically distributed (IID) source. We present a new compression technique, bit-wise arithmetic coding, that assigns fixed-length codewords to the quantizer output and uses arithmetic coding to compress the codewords, treating the codeword bits as independent. We examine the performance of this method and evaluate the overhead required when used block-adaptively. Simulation results are presented for Gaussian and Laplacian sources. This new technique could be used as the entropy coder in a transform or subband coding system.

Development of authentication code for multi-access optical code division multiplexing based quantum key distribution

NASA Astrophysics Data System (ADS)

Taiwo, Ambali; Alnassar, Ghusoon; Bakar, M. H. Abu; Khir, M. F. Abdul; Mahdi, Mohd Adzir; Mokhtar, M.

2018-05-01

One-weight authentication code for multi-user quantum key distribution (QKD) is proposed. The code is developed for Optical Code Division Multiplexing (OCDMA) based QKD network. A unique address assigned to individual user, coupled with degrading probability of predicting the source of the qubit transmitted in the channel offer excellent secure mechanism against any form of channel attack on OCDMA based QKD network. Flexibility in design as well as ease of modifying the number of users are equally exceptional quality presented by the code in contrast to Optical Orthogonal Code (OOC) earlier implemented for the same purpose. The code was successfully applied to eight simultaneous users at effective key rate of 32 bps over 27 km transmission distance.

Cellular dosimetry calculations for Strontium-90 using Monte Carlo code PENELOPE.

PubMed

Hocine, Nora; Farlay, Delphine; Boivin, Georges; Franck, Didier; Agarande, Michelle

2014-11-01

To improve risk assessments associated with chronic exposure to Strontium-90 (Sr-90), for both the environment and human health, it is necessary to know the energy distribution in specific cells or tissue. Monte Carlo (MC) simulation codes are extremely useful tools for calculating deposition energy. The present work was focused on the validation of the MC code PENetration and Energy LOss of Positrons and Electrons (PENELOPE) and the assessment of dose distribution to bone marrow cells from punctual Sr-90 source localized within the cortical bone part. S-values (absorbed dose per unit cumulated activity) calculations using Monte Carlo simulations were performed by using PENELOPE and Monte Carlo N-Particle eXtended (MCNPX). Cytoplasm, nucleus, cell surface, mouse femur bone and Sr-90 radiation source were simulated. Cells are assumed to be spherical with the radii of the cell and cell nucleus ranging from 2-10 μm. The Sr-90 source is assumed to be uniformly distributed in cell nucleus, cytoplasm and cell surface. The comparison of S-values calculated with PENELOPE to MCNPX results and the Medical Internal Radiation Dose (MIRD) values agreed very well since the relative deviations were less than 4.5%. The dose distribution to mouse bone marrow cells showed that the cells localized near the cortical part received the maximum dose. The MC code PENELOPE may prove useful for cellular dosimetry involving radiation transport through materials other than water, or for complex distributions of radionuclides and geometries.

Flow Instability Tests for a Particle Bed Reactor Nuclear Thermal Rocket Fuel Element

DTIC Science & Technology

1993-05-01

2.0 with GWBASIC or higher (DOS 5.0 was installed on the machine). Since the source code was written in BASIC, it was easy to make modifications...8217 AVAILABILITY STATEMENT 12b. DISTRIBUTION CODE Approved for Public Release IAW 190-1 Distribution Unlimited MICHAEL M. BRICKER, SMSgt, USAF Chief...Administration 13. ABSTRACT (Maximum 200 words) i.14. SUBJECT TERMS 15. NUMBER OF PAGES 339 16. PRICE CODE 󈧕. SECURITY CLASSIFICATION 18. SECURITY

Distributed Coding of Compressively Sensed Sources

NASA Astrophysics Data System (ADS)

Goukhshtein, Maxim

In this work we propose a new method for compressing multiple correlated sources with a very low-complexity encoder in the presence of side information. Our approach uses ideas from compressed sensing and distributed source coding. At the encoder, syndromes of the quantized compressively sensed sources are generated and transmitted. The decoder uses side information to predict the compressed sources. The predictions are then used to recover the quantized measurements via a two-stage decoding process consisting of bitplane prediction and syndrome decoding. Finally, guided by the structure of the sources and the side information, the sources are reconstructed from the recovered measurements. As a motivating example, we consider the compression of multispectral images acquired on board satellites, where resources, such as computational power and memory, are scarce. Our experimental results exhibit a significant improvement in the rate-distortion trade-off when compared against approaches with similar encoder complexity.

LENSED: a code for the forward reconstruction of lenses and sources from strong lensing observations

NASA Astrophysics Data System (ADS)

Tessore, Nicolas; Bellagamba, Fabio; Metcalf, R. Benton

2016-12-01

Robust modelling of strong lensing systems is fundamental to exploit the information they contain about the distribution of matter in galaxies and clusters. In this work, we present LENSED, a new code which performs forward parametric modelling of strong lenses. LENSED takes advantage of a massively parallel ray-tracing kernel to perform the necessary calculations on a modern graphics processing unit (GPU). This makes the precise rendering of the background lensed sources much faster, and allows the simultaneous optimization of tens of parameters for the selected model. With a single run, the code is able to obtain the full posterior probability distribution for the lens light, the mass distribution and the background source at the same time. LENSED is first tested on mock images which reproduce realistic space-based observations of lensing systems. In this way, we show that it is able to recover unbiased estimates of the lens parameters, even when the sources do not follow exactly the assumed model. Then, we apply it to a subsample of the Sloan Lens ACS Survey lenses, in order to demonstrate its use on real data. The results generally agree with the literature, and highlight the flexibility and robustness of the algorithm.

Theory and Performance of AIMS for Active Interrogation

NASA Astrophysics Data System (ADS)

Walters, William J.; Royston, Katherine E. K.; Haghighat, Alireza

2014-06-01

A hybrid Monte Carlo and deterministic methodology has been developed for application to active interrogation systems. The methodology consists of four steps: i) determination of neutron flux distribution due to neutron source transport and subcritical multiplication; ii) generation of gamma source distribution from (n, γ) interactions; iii) determination of gamma current at a detector window; iv) detection of gammas by the detector. This paper discusses the theory and results of the first three steps for the case of a cargo container with a sphere of HEU in third-density water. In the first step, a response-function formulation has been developed to calculate the subcritical multiplication and neutron flux distribution. Response coefficients are pre-calculated using the MCNP5 Monte Carlo code. The second step uses the calculated neutron flux distribution and Bugle-96 (n, γ) cross sections to find the resulting gamma source distribution. Finally, in the third step the gamma source distribution is coupled with a pre-calculated adjoint function to determine the gamma flux at a detector window. A code, AIMS (Active Interrogation for Monitoring Special-Nuclear-materials), has been written to output the gamma current for an source-detector assembly scanning across the cargo using the pre-calculated values and takes significantly less time than a reference MCNP5 calculation.

Neutron skyshine from intense 14-MeV neutron source facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nakamura, T.; Hayashi, K.; Takahashi, A.

1985-07-01

The dose distribution and the spectrum variation of neutrons due to the skyshine effect have been measured with the high-efficiency rem counter, the multisphere spectrometer, and the NE-213 scintillator in the environment surrounding an intense 14-MeV neutron source facility. The dose distribution and the energy spectra of neutrons around the facility used as a skyshine source have also been measured to enable the absolute evaluation of the skyshine effect. The skyshine effect was analyzed by two multigroup Monte Carlo codes, NIMSAC and MMCR-2, by two discrete ordinates S /sub n/ codes, ANISN and DOT3.5, and by the shield structure designmore » code for skyshine, SKYSHINE-II. The calculated results show good agreement with the measured results in absolute values. These experimental results should be useful as benchmark data for shyshine analysis and for shielding design of fusion facilities.« less

Source Authentication for Code Dissemination Supporting Dynamic Packet Size in Wireless Sensor Networks.

PubMed

Kim, Daehee; Kim, Dongwan; An, Sunshin

2016-07-09

Code dissemination in wireless sensor networks (WSNs) is a procedure for distributing a new code image over the air in order to update programs. Due to the fact that WSNs are mostly deployed in unattended and hostile environments, secure code dissemination ensuring authenticity and integrity is essential. Recent works on dynamic packet size control in WSNs allow enhancing the energy efficiency of code dissemination by dynamically changing the packet size on the basis of link quality. However, the authentication tokens attached by the base station become useless in the next hop where the packet size can vary according to the link quality of the next hop. In this paper, we propose three source authentication schemes for code dissemination supporting dynamic packet size. Compared to traditional source authentication schemes such as μTESLA and digital signatures, our schemes provide secure source authentication under the environment, where the packet size changes in each hop, with smaller energy consumption.

Source Authentication for Code Dissemination Supporting Dynamic Packet Size in Wireless Sensor Networks †

PubMed Central

Kim, Daehee; Kim, Dongwan; An, Sunshin

2016-01-01

Code dissemination in wireless sensor networks (WSNs) is a procedure for distributing a new code image over the air in order to update programs. Due to the fact that WSNs are mostly deployed in unattended and hostile environments, secure code dissemination ensuring authenticity and integrity is essential. Recent works on dynamic packet size control in WSNs allow enhancing the energy efficiency of code dissemination by dynamically changing the packet size on the basis of link quality. However, the authentication tokens attached by the base station become useless in the next hop where the packet size can vary according to the link quality of the next hop. In this paper, we propose three source authentication schemes for code dissemination supporting dynamic packet size. Compared to traditional source authentication schemes such as μTESLA and digital signatures, our schemes provide secure source authentication under the environment, where the packet size changes in each hop, with smaller energy consumption. PMID:27409616

Maximum aposteriori joint source/channel coding

NASA Technical Reports Server (NTRS)

Sayood, Khalid; Gibson, Jerry D.

1991-01-01

A maximum aposteriori probability (MAP) approach to joint source/channel coder design is presented in this paper. This method attempts to explore a technique for designing joint source/channel codes, rather than ways of distributing bits between source coders and channel coders. For a nonideal source coder, MAP arguments are used to design a decoder which takes advantage of redundancy in the source coder output to perform error correction. Once the decoder is obtained, it is analyzed with the purpose of obtaining 'desirable properties' of the channel input sequence for improving overall system performance. Finally, an encoder design which incorporates these properties is proposed.

egs_brachy: a versatile and fast Monte Carlo code for brachytherapy

NASA Astrophysics Data System (ADS)

Chamberland, Marc J. P.; Taylor, Randle E. P.; Rogers, D. W. O.; Thomson, Rowan M.

2016-12-01

egs_brachy is a versatile and fast Monte Carlo (MC) code for brachytherapy applications. It is based on the EGSnrc code system, enabling simulation of photons and electrons. Complex geometries are modelled using the EGSnrc C++ class library and egs_brachy includes a library of geometry models for many brachytherapy sources, in addition to eye plaques and applicators. Several simulation efficiency enhancing features are implemented in the code. egs_brachy is benchmarked by comparing TG-43 source parameters of three source models to previously published values. 3D dose distributions calculated with egs_brachy are also compared to ones obtained with the BrachyDose code. Well-defined simulations are used to characterize the effectiveness of many efficiency improving techniques, both as an indication of the usefulness of each technique and to find optimal strategies. Efficiencies and calculation times are characterized through single source simulations and simulations of idealized and typical treatments using various efficiency improving techniques. In general, egs_brachy shows agreement within uncertainties with previously published TG-43 source parameter values. 3D dose distributions from egs_brachy and BrachyDose agree at the sub-percent level. Efficiencies vary with radionuclide and source type, number of sources, phantom media, and voxel size. The combined effects of efficiency-improving techniques in egs_brachy lead to short calculation times: simulations approximating prostate and breast permanent implant (both with (2 mm)3 voxels) and eye plaque (with (1 mm)3 voxels) treatments take between 13 and 39 s, on a single 2.5 GHz Intel Xeon E5-2680 v3 processor core, to achieve 2% average statistical uncertainty on doses within the PTV. egs_brachy will be released as free and open source software to the research community.

egs_brachy: a versatile and fast Monte Carlo code for brachytherapy.

PubMed

Chamberland, Marc J P; Taylor, Randle E P; Rogers, D W O; Thomson, Rowan M

2016-12-07

egs_brachy is a versatile and fast Monte Carlo (MC) code for brachytherapy applications. It is based on the EGSnrc code system, enabling simulation of photons and electrons. Complex geometries are modelled using the EGSnrc C++ class library and egs_brachy includes a library of geometry models for many brachytherapy sources, in addition to eye plaques and applicators. Several simulation efficiency enhancing features are implemented in the code. egs_brachy is benchmarked by comparing TG-43 source parameters of three source models to previously published values. 3D dose distributions calculated with egs_brachy are also compared to ones obtained with the BrachyDose code. Well-defined simulations are used to characterize the effectiveness of many efficiency improving techniques, both as an indication of the usefulness of each technique and to find optimal strategies. Efficiencies and calculation times are characterized through single source simulations and simulations of idealized and typical treatments using various efficiency improving techniques. In general, egs_brachy shows agreement within uncertainties with previously published TG-43 source parameter values. 3D dose distributions from egs_brachy and BrachyDose agree at the sub-percent level. Efficiencies vary with radionuclide and source type, number of sources, phantom media, and voxel size. The combined effects of efficiency-improving techniques in egs_brachy lead to short calculation times: simulations approximating prostate and breast permanent implant (both with (2 mm) 3 voxels) and eye plaque (with (1 mm) 3 voxels) treatments take between 13 and 39 s, on a single 2.5 GHz Intel Xeon E5-2680 v3 processor core, to achieve 2% average statistical uncertainty on doses within the PTV. egs_brachy will be released as free and open source software to the research community.

26 CFR 1.6042-3 - Dividends subject to reporting.

Code of Federal Regulations, 2012 CFR

2012-04-01

... documentation of foreign status and definition of U.S. payor and non-U.S. payor) shall apply. The provisions of... the Internal Revenue Code (Code). (iv) Distributions or payments from sources outside the United States (as determined under the provisions of part I, subchapter N, chapter 1 of the Code and the...

Synthetic neutron camera and spectrometer in JET based on AFSI-ASCOT simulations

NASA Astrophysics Data System (ADS)

Sirén, P.; Varje, J.; Weisen, H.; Koskela, T.; contributors, JET

2017-09-01

The ASCOT Fusion Source Integrator (AFSI) has been used to calculate neutron production rates and spectra corresponding to the JET 19-channel neutron camera (KN3) and the time-of-flight spectrometer (TOFOR) as ideal diagnostics, without detector-related effects. AFSI calculates fusion product distributions in 4D, based on Monte Carlo integration from arbitrary reactant distribution functions. The distribution functions were calculated by the ASCOT Monte Carlo particle orbit following code for thermal, NBI and ICRH particle reactions. Fusion cross-sections were defined based on the Bosch-Hale model and both DD and DT reactions have been included. Neutrons generated by AFSI-ASCOT simulations have already been applied as a neutron source of the Serpent neutron transport code in ITER studies. Additionally, AFSI has been selected to be a main tool as the fusion product generator in the complete analysis calculation chain: ASCOT - AFSI - SERPENT (neutron and gamma transport Monte Carlo code) - APROS (system and power plant modelling code), which encompasses the plasma as an energy source, heat deposition in plant structures as well as cooling and balance-of-plant in DEMO applications and other reactor relevant analyses. This conference paper presents the first results and validation of the AFSI DD fusion model for different auxiliary heating scenarios (NBI, ICRH) with very different fast particle distribution functions. Both calculated quantities (production rates and spectra) have been compared with experimental data from KN3 and synthetic spectrometer data from ControlRoom code. No unexplained differences have been observed. In future work, AFSI will be extended for synthetic gamma diagnostics and additionally, AFSI will be used as part of the neutron transport calculation chain to model real diagnostics instead of ideal synthetic diagnostics for quantitative benchmarking.

Bit-Wise Arithmetic Coding For Compression Of Data

NASA Technical Reports Server (NTRS)

Kiely, Aaron

1996-01-01

Bit-wise arithmetic coding is data-compression scheme intended especially for use with uniformly quantized data from source with Gaussian, Laplacian, or similar probability distribution function. Code words of fixed length, and bits treated as being independent. Scheme serves as means of progressive transmission or of overcoming buffer-overflow or rate constraint limitations sometimes arising when data compression used.

A new Bayesian Earthquake Analysis Tool (BEAT)

NASA Astrophysics Data System (ADS)

Vasyura-Bathke, Hannes; Dutta, Rishabh; Jónsson, Sigurjón; Mai, Martin

2017-04-01

Modern earthquake source estimation studies increasingly use non-linear optimization strategies to estimate kinematic rupture parameters, often considering geodetic and seismic data jointly. However, the optimization process is complex and consists of several steps that need to be followed in the earthquake parameter estimation procedure. These include pre-describing or modeling the fault geometry, calculating the Green's Functions (often assuming a layered elastic half-space), and estimating the distributed final slip and possibly other kinematic source parameters. Recently, Bayesian inference has become popular for estimating posterior distributions of earthquake source model parameters given measured/estimated/assumed data and model uncertainties. For instance, some research groups consider uncertainties of the layered medium and propagate these to the source parameter uncertainties. Other groups make use of informative priors to reduce the model parameter space. In addition, innovative sampling algorithms have been developed that efficiently explore the often high-dimensional parameter spaces. Compared to earlier studies, these improvements have resulted in overall more robust source model parameter estimates that include uncertainties. However, the computational demands of these methods are high and estimation codes are rarely distributed along with the published results. Even if codes are made available, it is often difficult to assemble them into a single optimization framework as they are typically coded in different programing languages. Therefore, further progress and future applications of these methods/codes are hampered, while reproducibility and validation of results has become essentially impossible. In the spirit of providing open-access and modular codes to facilitate progress and reproducible research in earthquake source estimations, we undertook the effort of producing BEAT, a python package that comprises all the above-mentioned features in one single programing environment. The package is build on top of the pyrocko seismological toolbox (www.pyrocko.org) and makes use of the pymc3 module for Bayesian statistical model fitting. BEAT is an open-source package (https://github.com/hvasbath/beat) and we encourage and solicit contributions to the project. In this contribution, we present our strategy for developing BEAT, show application examples, and discuss future developments.

mGrid: A load-balanced distributed computing environment for the remote execution of the user-defined Matlab code

PubMed Central

Karpievitch, Yuliya V; Almeida, Jonas S

2006-01-01

Background Matlab, a powerful and productive language that allows for rapid prototyping, modeling and simulation, is widely used in computational biology. Modeling and simulation of large biological systems often require more computational resources then are available on a single computer. Existing distributed computing environments like the Distributed Computing Toolbox, MatlabMPI, Matlab*G and others allow for the remote (and possibly parallel) execution of Matlab commands with varying support for features like an easy-to-use application programming interface, load-balanced utilization of resources, extensibility over the wide area network, and minimal system administration skill requirements. However, all of these environments require some level of access to participating machines to manually distribute the user-defined libraries that the remote call may invoke. Results mGrid augments the usual process distribution seen in other similar distributed systems by adding facilities for user code distribution. mGrid's client-side interface is an easy-to-use native Matlab toolbox that transparently executes user-defined code on remote machines (i.e. the user is unaware that the code is executing somewhere else). Run-time variables are automatically packed and distributed with the user-defined code and automated load-balancing of remote resources enables smooth concurrent execution. mGrid is an open source environment. Apart from the programming language itself, all other components are also open source, freely available tools: light-weight PHP scripts and the Apache web server. Conclusion Transparent, load-balanced distribution of user-defined Matlab toolboxes and rapid prototyping of many simple parallel applications can now be done with a single easy-to-use Matlab command. Because mGrid utilizes only Matlab, light-weight PHP scripts and the Apache web server, installation and configuration are very simple. Moreover, the web-based infrastructure of mGrid allows for it to be easily extensible over the Internet. PMID:16539707

mGrid: a load-balanced distributed computing environment for the remote execution of the user-defined Matlab code.

PubMed

Karpievitch, Yuliya V; Almeida, Jonas S

2006-03-15

Matlab, a powerful and productive language that allows for rapid prototyping, modeling and simulation, is widely used in computational biology. Modeling and simulation of large biological systems often require more computational resources then are available on a single computer. Existing distributed computing environments like the Distributed Computing Toolbox, MatlabMPI, Matlab*G and others allow for the remote (and possibly parallel) execution of Matlab commands with varying support for features like an easy-to-use application programming interface, load-balanced utilization of resources, extensibility over the wide area network, and minimal system administration skill requirements. However, all of these environments require some level of access to participating machines to manually distribute the user-defined libraries that the remote call may invoke. mGrid augments the usual process distribution seen in other similar distributed systems by adding facilities for user code distribution. mGrid's client-side interface is an easy-to-use native Matlab toolbox that transparently executes user-defined code on remote machines (i.e. the user is unaware that the code is executing somewhere else). Run-time variables are automatically packed and distributed with the user-defined code and automated load-balancing of remote resources enables smooth concurrent execution. mGrid is an open source environment. Apart from the programming language itself, all other components are also open source, freely available tools: light-weight PHP scripts and the Apache web server. Transparent, load-balanced distribution of user-defined Matlab toolboxes and rapid prototyping of many simple parallel applications can now be done with a single easy-to-use Matlab command. Because mGrid utilizes only Matlab, light-weight PHP scripts and the Apache web server, installation and configuration are very simple. Moreover, the web-based infrastructure of mGrid allows for it to be easily extensible over the Internet.

InterProScan 5: genome-scale protein function classification

PubMed Central

Jones, Philip; Binns, David; Chang, Hsin-Yu; Fraser, Matthew; Li, Weizhong; McAnulla, Craig; McWilliam, Hamish; Maslen, John; Mitchell, Alex; Nuka, Gift; Pesseat, Sebastien; Quinn, Antony F.; Sangrador-Vegas, Amaia; Scheremetjew, Maxim; Yong, Siew-Yit; Lopez, Rodrigo; Hunter, Sarah

2014-01-01

Motivation: Robust large-scale sequence analysis is a major challenge in modern genomic science, where biologists are frequently trying to characterize many millions of sequences. Here, we describe a new Java-based architecture for the widely used protein function prediction software package InterProScan. Developments include improvements and additions to the outputs of the software and the complete reimplementation of the software framework, resulting in a flexible and stable system that is able to use both multiprocessor machines and/or conventional clusters to achieve scalable distributed data analysis. InterProScan is freely available for download from the EMBl-EBI FTP site and the open source code is hosted at Google Code. Availability and implementation: InterProScan is distributed via FTP at ftp://ftp.ebi.ac.uk/pub/software/unix/iprscan/5/ and the source code is available from http://code.google.com/p/interproscan/. Contact: http://www.ebi.ac.uk/support or interhelp@ebi.ac.uk or mitchell@ebi.ac.uk PMID:24451626

Monte Carlo dose calculations of beta-emitting sources for intravascular brachytherapy: a comparison between EGS4, EGSnrc, and MCNP.

PubMed

Wang, R; Li, X A

2001-02-01

The dose parameters for the beta-particle emitting 90Sr/90Y source for intravascular brachytherapy (IVBT) have been calculated by different investigators. At a distant distance from the source, noticeable differences are seen in these parameters calculated using different Monte Carlo codes. The purpose of this work is to quantify as well as to understand these differences. We have compared a series of calculations using an EGS4, an EGSnrc, and the MCNP Monte Carlo codes. Data calculated and compared include the depth dose curve for a broad parallel beam of electrons, and radial dose distributions for point electron sources (monoenergetic or polyenergetic) and for a real 90Sr/90Y source. For the 90Sr/90Y source, the doses at the reference position (2 mm radial distance) calculated by the three code agree within 2%. However, the differences between the dose calculated by the three codes can be over 20% in the radial distance range interested in IVBT. The difference increases with radial distance from source, and reaches 30% at the tail of dose curve. These differences may be partially attributed to the different multiple scattering theories and Monte Carlo models for electron transport adopted in these three codes. Doses calculated by the EGSnrc code are more accurate than those by the EGS4. The two calculations agree within 5% for radial distance <6 mm.

Robust video transmission with distributed source coded auxiliary channel.

PubMed

Wang, Jiajun; Majumdar, Abhik; Ramchandran, Kannan

2009-12-01

We propose a novel solution to the problem of robust, low-latency video transmission over lossy channels. Predictive video codecs, such as MPEG and H.26x, are very susceptible to prediction mismatch between encoder and decoder or "drift" when there are packet losses. These mismatches lead to a significant degradation in the decoded quality. To address this problem, we propose an auxiliary codec system that sends additional information alongside an MPEG or H.26x compressed video stream to correct for errors in decoded frames and mitigate drift. The proposed system is based on the principles of distributed source coding and uses the (possibly erroneous) MPEG/H.26x decoder reconstruction as side information at the auxiliary decoder. The distributed source coding framework depends upon knowing the statistical dependency (or correlation) between the source and the side information. We propose a recursive algorithm to analytically track the correlation between the original source frame and the erroneous MPEG/H.26x decoded frame. Finally, we propose a rate-distortion optimization scheme to allocate the rate used by the auxiliary encoder among the encoding blocks within a video frame. We implement the proposed system and present extensive simulation results that demonstrate significant gains in performance both visually and objectively (on the order of 2 dB in PSNR over forward error correction based solutions and 1.5 dB in PSNR over intrarefresh based solutions for typical scenarios) under tight latency constraints.

On the optimality of code options for a universal noiseless coder

NASA Technical Reports Server (NTRS)

Yeh, Pen-Shu; Rice, Robert F.; Miller, Warner

1991-01-01

A universal noiseless coding structure was developed that provides efficient performance over an extremely broad range of source entropy. This is accomplished by adaptively selecting the best of several easily implemented variable length coding algorithms. Custom VLSI coder and decoder modules capable of processing over 20 million samples per second are currently under development. The first of the code options used in this module development is shown to be equivalent to a class of Huffman code under the Humblet condition, other options are shown to be equivalent to the Huffman codes of a modified Laplacian symbol set, at specified symbol entropy values. Simulation results are obtained on actual aerial imagery, and they confirm the optimality of the scheme. On sources having Gaussian or Poisson distributions, coder performance is also projected through analysis and simulation.

Model-Based Least Squares Reconstruction of Coded Source Neutron Radiographs: Integrating the ORNL HFIR CG1D Source Model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Santos-Villalobos, Hector J; Gregor, Jens; Bingham, Philip R

2014-01-01

At the present, neutron sources cannot be fabricated small and powerful enough in order to achieve high resolution radiography while maintaining an adequate flux. One solution is to employ computational imaging techniques such as a Magnified Coded Source Imaging (CSI) system. A coded-mask is placed between the neutron source and the object. The system resolution is increased by reducing the size of the mask holes and the flux is increased by increasing the size of the coded-mask and/or the number of holes. One limitation of such system is that the resolution of current state-of-the-art scintillator-based detectors caps around 50um. Tomore » overcome this challenge, the coded-mask and object are magnified by making the distance from the coded-mask to the object much smaller than the distance from object to detector. In previous work, we have shown via synthetic experiments that our least squares method outperforms other methods in image quality and reconstruction precision because of the modeling of the CSI system components. However, the validation experiments were limited to simplistic neutron sources. In this work, we aim to model the flux distribution of a real neutron source and incorporate such a model in our least squares computational system. We provide a full description of the methodology used to characterize the neutron source and validate the method with synthetic experiments.« less

Multi-Source Cooperative Data Collection with a Mobile Sink for the Wireless Sensor Network.

PubMed

Han, Changcai; Yang, Jinsheng

2017-10-30

The multi-source cooperation integrating distributed low-density parity-check codes is investigated to jointly collect data from multiple sensor nodes to the mobile sink in the wireless sensor network. The one-round and two-round cooperative data collection schemes are proposed according to the moving trajectories of the sink node. Specifically, two sparse cooperation models are firstly formed based on geographical locations of sensor source nodes, the impairment of inter-node wireless channels and moving trajectories of the mobile sink. Then, distributed low-density parity-check codes are devised to match the directed graphs and cooperation matrices related with the cooperation models. In the proposed schemes, each source node has quite low complexity attributed to the sparse cooperation and the distributed processing. Simulation results reveal that the proposed cooperative data collection schemes obtain significant bit error rate performance and the two-round cooperation exhibits better performance compared with the one-round scheme. The performance can be further improved when more source nodes participate in the sparse cooperation. For the two-round data collection schemes, the performance is evaluated for the wireless sensor networks with different moving trajectories and the variant data sizes.

Multi-Source Cooperative Data Collection with a Mobile Sink for the Wireless Sensor Network

PubMed Central

Han, Changcai; Yang, Jinsheng

2017-01-01

The multi-source cooperation integrating distributed low-density parity-check codes is investigated to jointly collect data from multiple sensor nodes to the mobile sink in the wireless sensor network. The one-round and two-round cooperative data collection schemes are proposed according to the moving trajectories of the sink node. Specifically, two sparse cooperation models are firstly formed based on geographical locations of sensor source nodes, the impairment of inter-node wireless channels and moving trajectories of the mobile sink. Then, distributed low-density parity-check codes are devised to match the directed graphs and cooperation matrices related with the cooperation models. In the proposed schemes, each source node has quite low complexity attributed to the sparse cooperation and the distributed processing. Simulation results reveal that the proposed cooperative data collection schemes obtain significant bit error rate performance and the two-round cooperation exhibits better performance compared with the one-round scheme. The performance can be further improved when more source nodes participate in the sparse cooperation. For the two-round data collection schemes, the performance is evaluated for the wireless sensor networks with different moving trajectories and the variant data sizes. PMID:29084155

Hybrid Raman/Brillouin-optical-time-domain-analysis-distributed optical fiber sensors based on cyclic pulse coding.

PubMed

Taki, M; Signorini, A; Oton, C J; Nannipieri, T; Di Pasquale, F

2013-10-15

We experimentally demonstrate the use of cyclic pulse coding for distributed strain and temperature measurements in hybrid Raman/Brillouin optical time-domain analysis (BOTDA) optical fiber sensors. The highly integrated proposed solution effectively addresses the strain/temperature cross-sensitivity issue affecting standard BOTDA sensors, allowing for simultaneous meter-scale strain and temperature measurements over 10 km of standard single mode fiber using a single narrowband laser source only.

Supersonic propulsion simulation by incorporating component models in the large perturbation inlet (LAPIN) computer code

NASA Technical Reports Server (NTRS)

Cole, Gary L.; Richard, Jacques C.

1991-01-01

An approach to simulating the internal flows of supersonic propulsion systems is presented. The approach is based on a fairly simple modification of the Large Perturbation Inlet (LAPIN) computer code. LAPIN uses a quasi-one dimensional, inviscid, unsteady formulation of the continuity, momentum, and energy equations. The equations are solved using a shock capturing, finite difference algorithm. The original code, developed for simulating supersonic inlets, includes engineering models of unstart/restart, bleed, bypass, and variable duct geometry, by means of source terms in the equations. The source terms also provide a mechanism for incorporating, with the inlet, propulsion system components such as compressor stages, combustors, and turbine stages. This requires each component to be distributed axially over a number of grid points. Because of the distributed nature of such components, this representation should be more accurate than a lumped parameter model. Components can be modeled by performance map(s), which in turn are used to compute the source terms. The general approach is described. Then, simulation of a compressor/fan stage is discussed to show the approach in detail.

Open Source Software Compliance within the Government

DTIC Science & Technology

2016-12-01

The exception to this rule is the various General Public License (GPLs), which consider all distributions to contractors as outside distribution...is developed by a contractor at the government’s expense or for the government’s exclusive use. The third condition that must be met is that ERDC...executables and source code can only be offered by an authorized delivering entity to an authorized receiving entity. This means that contractors , with

Energy spectra unfolding of fast neutron sources using the group method of data handling and decision tree algorithms

NASA Astrophysics Data System (ADS)

Hosseini, Seyed Abolfazl; Afrakoti, Iman Esmaili Paeen

2017-04-01

Accurate unfolding of the energy spectrum of a neutron source gives important information about unknown neutron sources. The obtained information is useful in many areas like nuclear safeguards, nuclear nonproliferation, and homeland security. In the present study, the energy spectrum of a poly-energetic fast neutron source is reconstructed using the developed computational codes based on the Group Method of Data Handling (GMDH) and Decision Tree (DT) algorithms. The neutron pulse height distribution (neutron response function) in the considered NE-213 liquid organic scintillator has been simulated using the developed MCNPX-ESUT computational code (MCNPX-Energy engineering of Sharif University of Technology). The developed computational codes based on the GMDH and DT algorithms use some data for training, testing and validation steps. In order to prepare the required data, 4000 randomly generated energy spectra distributed over 52 bins are used. The randomly generated energy spectra and the simulated neutron pulse height distributions by MCNPX-ESUT for each energy spectrum are used as the output and input data. Since there is no need to solve the inverse problem with an ill-conditioned response matrix, the unfolded energy spectrum has the highest accuracy. The 241Am-9Be and 252Cf neutron sources are used in the validation step of the calculation. The unfolded energy spectra for the used fast neutron sources have an excellent agreement with the reference ones. Also, the accuracy of the unfolded energy spectra obtained using the GMDH is slightly better than those obtained from the DT. The results obtained in the present study have good accuracy in comparison with the previously published paper based on the logsig and tansig transfer functions.

Characterization and Remediation of Contaminated Sites:Modeling, Measurement and Assessment

NASA Astrophysics Data System (ADS)

Basu, N. B.; Rao, P. C.; Poyer, I. C.; Christ, J. A.; Zhang, C. Y.; Jawitz, J. W.; Werth, C. J.; Annable, M. D.; Hatfield, K.

2008-05-01

The complexity of natural systems makes it impossible to estimate parameters at the required level of spatial and temporal detail. Thus, it becomes necessary to transition from spatially distributed parameters to spatially integrated parameters that are capable of adequately capturing the system dynamics, without always accounting for local process behavior. Contaminant flux across the source control plane is proposed as an integrated metric that captures source behavior and links it to plume dynamics. Contaminant fluxes were measured using an innovative technology, the passive flux meter at field sites contaminated with dense non-aqueous phase liquids or DNAPLs in the US and Australia. Flux distributions were observed to be positively or negatively correlated with the conductivity distribution, depending on the source characteristics of the site. The impact of partial source depletion on the mean contaminant flux and flux architecture was investigated in three-dimensional complex heterogeneous settings using the multiphase transport code UTCHEM and the reactive transport code ISCO3D. Source mass depletion reduced the mean contaminant flux approximately linearly, while the contaminant flux standard deviation reduced proportionally with the mean (i.e., coefficient of variation of flux distribution is constant with time). Similar analysis was performed using data from field sites, and the results confirmed the numerical simulations. The linearity of the mass depletion-flux reduction relationship indicates the ability to design remediation systems that deplete mass to achieve target reduction in source strength. Stability of the flux distribution indicates the ability to characterize the distributions in time once the initial distribution is known. Lagrangian techniques were used to predict contaminant flux behavior during source depletion in terms of the statistics of the hydrodynamic and DNAPL distribution. The advantage of the Lagrangian techniques lies in their small computation time and their inclusion of spatially integrated parameters that can be measured in the field using tracer tests. Analytical models that couple source depletion to plume transport were used for optimization of source and plume treatment. These models are being used for the development of decision and management tools (for DNAPL sites) that consider uncertainty assessments as an integral part of the decision-making process for contaminated site remediation.

Numerical simulation of ion charge breeding in electron beam ion source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, L., E-mail: zhao@far-tech.com; Kim, Jin-Soo

2014-02-15

The Electron Beam Ion Source particle-in-cell code (EBIS-PIC) tracks ions in an EBIS electron beam while updating electric potential self-consistently and atomic processes by the Monte Carlo method. Recent improvements to the code are reported in this paper. The ionization module has been improved by using experimental ionization energies and shell effects. The acceptance of injected ions and the emittance of extracted ion beam are calculated by extending EBIS-PIC to the beam line transport region. An EBIS-PIC simulation is performed for a Cs charge-breeding experiment at BNL. The charge state distribution agrees well with experiments, and additional simulation results ofmore » radial profiles and velocity space distributions of the trapped ions are presented.« less

Bremsstrahlung Dose Yield for High-Intensity Short-Pulse Laser–Solid Experiments

DOE PAGES

Liang, Taiee; Bauer, Johannes M.; Liu, James C.; ...

2016-12-01

A bremsstrahlung source term has been developed by the Radiation Protection (RP) group at SLAC National Accelerator Laboratory for high-intensity short-pulse laser–solid experiments between 10 17 and 10 22 W cm –2. This source term couples the particle-in-cell plasma code EPOCH and the radiation transport code FLUKA to estimate the bremsstrahlung dose yield from laser–solid interactions. EPOCH characterizes the energy distribution, angular distribution, and laser-to-electron conversion efficiency of the hot electrons from laser–solid interactions, and FLUKA utilizes this hot electron source term to calculate a bremsstrahlung dose yield (mSv per J of laser energy on target). The goal of thismore » paper is to provide RP guidelines and hazard analysis for high-intensity laser facilities. In conclusion, a comparison of the calculated bremsstrahlung dose yields to radiation measurement data is also made.« less

Bremsstrahlung Dose Yield for High-Intensity Short-Pulse Laser–Solid Experiments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liang, Taiee; Bauer, Johannes M.; Liu, James C.

A bremsstrahlung source term has been developed by the Radiation Protection (RP) group at SLAC National Accelerator Laboratory for high-intensity short-pulse laser–solid experiments between 10 17 and 10 22 W cm –2. This source term couples the particle-in-cell plasma code EPOCH and the radiation transport code FLUKA to estimate the bremsstrahlung dose yield from laser–solid interactions. EPOCH characterizes the energy distribution, angular distribution, and laser-to-electron conversion efficiency of the hot electrons from laser–solid interactions, and FLUKA utilizes this hot electron source term to calculate a bremsstrahlung dose yield (mSv per J of laser energy on target). The goal of thismore » paper is to provide RP guidelines and hazard analysis for high-intensity laser facilities. In conclusion, a comparison of the calculated bremsstrahlung dose yields to radiation measurement data is also made.« less

Symmetry-Based Variance Reduction Applied to 60Co Teletherapy Unit Monte Carlo Simulations

NASA Astrophysics Data System (ADS)

Sheikh-Bagheri, D.

A new variance reduction technique (VRT) is implemented in the BEAM code [1] to specifically improve the efficiency of calculating penumbral distributions of in-air fluence profiles calculated for isotopic sources. The simulations focus on 60Co teletherapy units. The VRT includes splitting of photons exiting the source capsule of a 60Co teletherapy source according to a splitting recipe and distributing the split photons randomly on the periphery of a circle, preserving the direction cosine along the beam axis, in addition to the energy of the photon. It is shown that the use of the VRT developed in this work can lead to a 6-9 fold improvement in the efficiency of the penumbral photon fluence of a 60Co beam compared to that calculated using the standard optimized BEAM code [1] (i.e., one with the proper selection of electron transport parameters).

Skin dose from radionuclide contamination on clothing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taylor, D.C.; Hussein, E.M.A.; Yuen, P.S.

1997-06-01

Skin dose due to radio nuclide contamination on clothing is calculated by Monte Carlo simulation of electron and photon radiation transport. Contamination due to a hot particle on some selected clothing geometries of cotton garment is simulated. The effect of backscattering in the surrounding air is taken into account. For each combination of source-clothing geometry, the dose distribution function in the skin, including the dose at tissue depths of 7 mg cm{sup -2} and 1,000 Mg cm{sup -2}, is calculated by simulating monoenergetic photon and electron sources. Skin dose due to contamination by a radionuclide is then determined by propermore » weighting of & monoenergetic dose distribution functions. The results are compared with the VARSKIN point-kernel code for some radionuclides, indicating that the latter code tends to under-estimate the dose for gamma and high energy beta sources while it overestimates skin dose for low energy beta sources. 13 refs., 4 figs., 2 tabs.« less

Nonlinear Real-Time Optical Signal Processing.

DTIC Science & Technology

1988-07-01

Principal Investigator B. K. Jenkins Signal and Image Processing Institute University of Southern California Mail Code 0272 Los Angeles, California...ADDRESS (09% SteW. Mnd ZIP Code ) 10. SOURC OF FUNONG NUMBERS Bldg. 410, Bolling AFB PROGAM CT TASK WORK UNIT Washington, D.C. 20332 EEETP.aso o 11...TAB Unmnnncced Justification By Distribution/ I O’ Availablility Codes I - ’_ ji and/or 2 I Summary During the period 1 July 1987 - 30 June 1988, the

A loosely coupled framework for terminology controlled distributed EHR search for patient cohort identification in clinical research.

PubMed

Zhao, Lei; Lim Choi Keung, Sarah N; Taweel, Adel; Tyler, Edward; Ogunsina, Ire; Rossiter, James; Delaney, Brendan C; Peterson, Kevin A; Hobbs, F D Richard; Arvanitis, Theodoros N

2012-01-01

Heterogeneous data models and coding schemes for electronic health records present challenges for automated search across distributed data sources. This paper describes a loosely coupled software framework based on the terminology controlled approach to enable the interoperation between the search interface and heterogeneous data sources. Software components interoperate via common terminology service and abstract criteria model so as to promote component reuse and incremental system evolution.

Sunlamp

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nutaro, James J

The purpose of this model was to facilitate the design of a control system that uses fine grained control of residential and small commercial HVAC loads to counterbalance voltage swings caused by intermittent solar power sources (e.g., rooftop panels) installed in that distribution circuit. Included is the source code and pre-compiled 64 bit dll for adding building HVAC loads to an OpenDSS distribution circuit. As written, the Makefile assumes you are using the Microsoft C++ development tools.

Plasma separation process. Betacell (BCELL) code, user's manual

NASA Astrophysics Data System (ADS)

Taherzadeh, M.

1987-11-01

The emergence of clearly defined applications for (small or large) amounts of long-life and reliable power sources has given the design and production of betavoltaic systems a new life. Moreover, because of the availability of the Plasma Separation Program, (PSP) at TRW, it is now possible to separate the most desirable radioisotopes for betacell power generating devices. A computer code, named BCELL, has been developed to model the betavoltaic concept by utilizing the available up-to-date source/cell parameters. In this program, attempts have been made to determine the betacell energy device maximum efficiency, degradation due to the emitting source radiation and source/cell lifetime power reduction processes. Additionally, comparison is made between the Schottky and PN junction devices for betacell battery design purposes. Certain computer code runs have been made to determine the JV distribution function and the upper limit of the betacell generated power for specified energy sources. A Ni beta emitting radioisotope was used for the energy source and certain semiconductors were used for the converter subsystem of the betacell system. Some results for a Promethium source are also given here for comparison.

Engineering High Assurance Distributed Cyber Physical Systems

DTIC Science & Technology

2015-01-15

decisions: number of interacting agents and co-dependent decisions made in real-time without causing interference . To engineer a high assurance DART...environment specification, architecture definition, domain-specific languages, design patterns, code - generation, analysis, test-generation, and simulation...include synchronization between the models and source code , debugging at the model level, expression of the design intent, and quality of service

DOE Office of Scientific and Technical Information (OSTI.GOV)

Purwaningsih, Anik

Dosimetric data for a brachytherapy source should be known before it used for clinical treatment. Iridium-192 source type H01 was manufactured by PRR-BATAN aimed to brachytherapy is not yet known its dosimetric data. Radial dose function and anisotropic dose distribution are some primary keys in brachytherapy source. Dose distribution for Iridium-192 source type H01 was obtained from the dose calculation formalism recommended in the AAPM TG-43U1 report using MCNPX 2.6.0 Monte Carlo simulation code. To know the effect of cavity on Iridium-192 type H01 caused by manufacturing process, also calculated on Iridium-192 type H01 if without cavity. The result ofmore » calculation of radial dose function and anisotropic dose distribution for Iridium-192 source type H01 were compared with another model of Iridium-192 source.« less

Simulation of a beam rotation system for a spallation source

NASA Astrophysics Data System (ADS)

Reiss, Tibor; Reggiani, Davide; Seidel, Mike; Talanov, Vadim; Wohlmuther, Michael

2015-04-01

With a nominal beam power of nearly 1 MW on target, the Swiss Spallation Neutron Source (SINQ), ranks among the world's most powerful spallation neutron sources. The proton beam transport to the SINQ target is carried out exclusively by means of linear magnetic elements. In the transport line to SINQ the beam is scattered in two meson production targets and as a consequence, at the SINQ target entrance the beam shape can be described by Gaussian distributions in transverse x and y directions with tails cut short by collimators. This leads to a highly nonuniform power distribution inside the SINQ target, giving rise to thermal and mechanical stresses. In view of a future proton beam intensity upgrade, the possibility of homogenizing the beam distribution by means of a fast beam rotation system is currently under investigation. Important aspects which need to be studied are the impact of a rotating proton beam on the resulting neutron spectra, spatial flux distributions and additional—previously not present—proton losses causing unwanted activation of accelerator components. Hence a new source description method was developed for the radiation transport code MCNPX. This new feature makes direct use of the results from the proton beam optics code TURTLE. Its advantage to existing MCNPX source options is that all phase space information and correlations of each primary beam particle computed with TURTLE are preserved and transferred to MCNPX. Simulations of the different beam distributions together with their consequences in terms of neutron production are presented in this publication. Additionally, a detailed description of the coupling method between TURTLE and MCNPX is provided.

QUANTUM ESPRESSO: a modular and open-source software project for quantum simulations of materials.

PubMed

Giannozzi, Paolo; Baroni, Stefano; Bonini, Nicola; Calandra, Matteo; Car, Roberto; Cavazzoni, Carlo; Ceresoli, Davide; Chiarotti, Guido L; Cococcioni, Matteo; Dabo, Ismaila; Dal Corso, Andrea; de Gironcoli, Stefano; Fabris, Stefano; Fratesi, Guido; Gebauer, Ralph; Gerstmann, Uwe; Gougoussis, Christos; Kokalj, Anton; Lazzeri, Michele; Martin-Samos, Layla; Marzari, Nicola; Mauri, Francesco; Mazzarello, Riccardo; Paolini, Stefano; Pasquarello, Alfredo; Paulatto, Lorenzo; Sbraccia, Carlo; Scandolo, Sandro; Sclauzero, Gabriele; Seitsonen, Ari P; Smogunov, Alexander; Umari, Paolo; Wentzcovitch, Renata M

2009-09-30

QUANTUM ESPRESSO is an integrated suite of computer codes for electronic-structure calculations and materials modeling, based on density-functional theory, plane waves, and pseudopotentials (norm-conserving, ultrasoft, and projector-augmented wave). The acronym ESPRESSO stands for opEn Source Package for Research in Electronic Structure, Simulation, and Optimization. It is freely available to researchers around the world under the terms of the GNU General Public License. QUANTUM ESPRESSO builds upon newly-restructured electronic-structure codes that have been developed and tested by some of the original authors of novel electronic-structure algorithms and applied in the last twenty years by some of the leading materials modeling groups worldwide. Innovation and efficiency are still its main focus, with special attention paid to massively parallel architectures, and a great effort being devoted to user friendliness. QUANTUM ESPRESSO is evolving towards a distribution of independent and interoperable codes in the spirit of an open-source project, where researchers active in the field of electronic-structure calculations are encouraged to participate in the project by contributing their own codes or by implementing their own ideas into existing codes.

Self-consistent modeling of electron cyclotron resonance ion sources

NASA Astrophysics Data System (ADS)

Girard, A.; Hitz, D.; Melin, G.; Serebrennikov, K.; Lécot, C.

2004-05-01

In order to predict the performances of electron cyclotron resonance ion source (ECRIS), it is necessary to perfectly model the different parts of these sources: (i) magnetic configuration; (ii) plasma characteristics; (iii) extraction system. The magnetic configuration is easily calculated via commercial codes; different codes also simulate the ion extraction, either in two dimension, or even in three dimension (to take into account the shape of the plasma at the extraction influenced by the hexapole). However the characteristics of the plasma are not always mastered. This article describes the self-consistent modeling of ECRIS: we have developed a code which takes into account the most important construction parameters: the size of the plasma (length, diameter), the mirror ratio and axial magnetic profile, whether a biased probe is installed or not. These input parameters are used to feed a self-consistent code, which calculates the characteristics of the plasma: electron density and energy, charge state distribution, plasma potential. The code is briefly described, and some of its most interesting results are presented. Comparisons are made between the calculations and the results obtained experimentally.

SU-C-201-03: Coded Aperture Gamma-Ray Imaging Using Pixelated Semiconductor Detectors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Joshi, S; Kaye, W; Jaworski, J

2015-06-15

Purpose: Improved localization of gamma-ray emissions from radiotracers is essential to the progress of nuclear medicine. Polaris is a portable, room-temperature operated gamma-ray imaging spectrometer composed of two 3×3 arrays of thick CdZnTe (CZT) detectors, which detect gammas between 30keV and 3MeV with energy resolution of <1% FWHM at 662keV. Compton imaging is used to map out source distributions in 4-pi space; however, is only effective above 300keV where Compton scatter is dominant. This work extends imaging to photoelectric energies (<300keV) using coded aperture imaging (CAI), which is essential for localization of Tc-99m (140keV). Methods: CAI, similar to the pinholemore » camera, relies on an attenuating mask, with open/closed elements, placed between the source and position-sensitive detectors. Partial attenuation of the source results in a “shadow” or count distribution that closely matches a portion of the mask pattern. Ideally, each source direction corresponds to a unique count distribution. Using backprojection reconstruction, the source direction is determined within the field of view. The knowledge of 3D position of interaction results in improved image quality. Results: Using a single array of detectors, a coded aperture mask, and multiple Co-57 (122keV) point sources, image reconstruction is performed in real-time, on an event-by-event basis, resulting in images with an angular resolution of ∼6 degrees. Although material nonuniformities contribute to image degradation, the superposition of images from individual detectors results in improved SNR. CAI was integrated with Compton imaging for a seamless transition between energy regimes. Conclusion: For the first time, CAI has been applied to thick, 3D position sensitive CZT detectors. Real-time, combined CAI and Compton imaging is performed using two 3×3 detector arrays, resulting in a source distribution in space. This system has been commercialized by H3D, Inc. and is being acquired for various applications worldwide, including proton therapy imaging R&D.« less

Modelling the phase curve and occultation of WASP-43b with SPIDERMAN

NASA Astrophysics Data System (ADS)

Louden, Tom

2017-06-01

Presenting SPIDERMAN, a fast code for calculating exoplanet phase curves and secondary eclipses with arbitrary two dimensional surface brightness distributions. SPIDERMAN uses an exact geometric algorithm to calculate the area of sub-regions of the planet that are occulted by the star, with no loss in numerical precision. The speed of this calculation makes it possible to run MCMCs to marginalise effectively over the underlying parameters controlling the brightness distribution of exoplanets. The code is fully open source and available over Github. We apply the code to the phase curve of WASP-43b using an analytical surface brightness distribution, and find an excellent fit to the data. We are able to place direct constraints on the physics of heat transport in the atmosphere, such as the ratio between advective and radiative timescales at different altitudes.

[Random Variable Read Me File

NASA Technical Reports Server (NTRS)

Teubert, Christopher; Sankararaman, Shankar; Cullo, Aiden

2017-01-01

Readme for the Random Variable Toolbox usable manner. is a Web-based Git version control repository hosting service. It is mostly used for computer code. It offers all of the distributed version control and source code management (SCM) functionality of Git as well as adding its own features. It provides access control and several collaboration features such as bug tracking, feature requests, task management, and wikis for every project.[3] GitHub offers both plans for private and free repositories on the same account[4] which are commonly used to host open-source software projects.[5] As of April 2017, GitHub reports having almost 20 million users and 57 million repositories,[6] making it the largest host of source code in the world.[7] GitHub has a mascot called Octocat, a cat with five tentacles and a human-like face

Development of a computer code to calculate the distribution of radionuclides within the human body by the biokinetic models of the ICRP.

PubMed

Matsumoto, Masaki; Yamanaka, Tsuneyasu; Hayakawa, Nobuhiro; Iwai, Satoshi; Sugiura, Nobuyuki

2015-03-01

This paper describes the Basic Radionuclide vAlue for Internal Dosimetry (BRAID) code, which was developed to calculate the time-dependent activity distribution in each organ and tissue characterised by the biokinetic compartmental models provided by the International Commission on Radiological Protection (ICRP). Translocation from one compartment to the next is taken to be governed by first-order kinetics, which is formulated by the first-order differential equations. In the source program of this code, the conservation equations are solved for the mass balance that describes the transfer of a radionuclide between compartments. This code is applicable to the evaluation of the radioactivity of nuclides in an organ or tissue without modification of the source program. It is also possible to handle easily the cases of the revision of the biokinetic model or the application of a uniquely defined model by a user, because this code is designed so that all information on the biokinetic model structure is imported from an input file. The sample calculations are performed with the ICRP model, and the results are compared with the analytic solutions using simple models. It is suggested that this code provides sufficient result for the dose estimation and interpretation of monitoring data. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

HELIOS-R: An Ultrafast, Open-Source Retrieval Code For Exoplanetary Atmosphere Characterization

NASA Astrophysics Data System (ADS)

LAVIE, Baptiste

2015-12-01

Atmospheric retrieval is a growing, new approach in the theory of exoplanet atmosphere characterization. Unlike self-consistent modeling it allows us to fully explore the parameter space, as well as the degeneracies between the parameters using a Bayesian framework. We present HELIOS-R, a very fast retrieving code written in Python and optimized for GPU computation. Once it is ready, HELIOS-R will be the first open-source atmospheric retrieval code accessible to the exoplanet community. As the new generation of direct imaging instruments (SPHERE, GPI) have started to gather data, the first version of HELIOS-R focuses on emission spectra. We use a 1D two-stream forward model for computing fluxes and couple it to an analytical temperature-pressure profile that is constructed to be in radiative equilibrium. We use our ultra-fast opacity calculator HELIOS-K (also open-source) to compute the opacities of CO2, H2O, CO and CH4 from the HITEMP database. We test both opacity sampling (which is typically used by other workers) and the method of k-distributions. Using this setup, we compute a grid of synthetic spectra and temperature-pressure profiles, which is then explored using a nested sampling algorithm. By focusing on model selection (Occam’s razor) through the explicit computation of the Bayesian evidence, nested sampling allows us to deal with current sparse data as well as upcoming high-resolution observations. Once the best model is selected, HELIOS-R provides posterior distributions of the parameters. As a test for our code we studied HR8799 system and compared our results with the previous analysis of Lee, Heng & Irwin (2013), which used the proprietary NEMESIS retrieval code. HELIOS-R and HELIOS-K are part of the set of open-source community codes we named the Exoclimes Simulation Platform (www.exoclime.org).

Performance and Architecture Lab Modeling Tool

DOE Office of Scientific and Technical Information (OSTI.GOV)

2014-06-19

Analytical application performance models are critical for diagnosing performance-limiting resources, optimizing systems, and designing machines. Creating models, however, is difficult. Furthermore, models are frequently expressed in forms that are hard to distribute and validate. The Performance and Architecture Lab Modeling tool, or Palm, is a modeling tool designed to make application modeling easier. Palm provides a source code modeling annotation language. Not only does the modeling language divide the modeling task into sub problems, it formally links an application's source code with its model. This link is important because a model's purpose is to capture application behavior. Furthermore, this linkmore » makes it possible to define rules for generating models according to source code organization. Palm generates hierarchical models according to well-defined rules. Given an application, a set of annotations, and a representative execution environment, Palm will generate the same model. A generated model is a an executable program whose constituent parts directly correspond to the modeled application. Palm generates models by combining top-down (human-provided) semantic insight with bottom-up static and dynamic analysis. A model's hierarchy is defined by static and dynamic source code structure. Because Palm coordinates models and source code, Palm's models are 'first-class' and reproducible. Palm automates common modeling tasks. For instance, Palm incorporates measurements to focus attention, represent constant behavior, and validate models. Palm's workflow is as follows. The workflow's input is source code annotated with Palm modeling annotations. The most important annotation models an instance of a block of code. Given annotated source code, the Palm Compiler produces executables and the Palm Monitor collects a representative performance profile. The Palm Generator synthesizes a model based on the static and dynamic mapping of annotations to program behavior. The model -- an executable program -- is a hierarchical composition of annotation functions, synthesized functions, statistics for runtime values, and performance measurements.« less

Design of an Orbital Inspection Satellite

DTIC Science & Technology

1986-12-01

ADDRESS (City, State, and ZIP Code ) 10. SOURCE OF FUNDING NUMBERS PROGRAM PROJECT TASK WORK UNITELEMENT NO. NO. NO. CCESSION NO. 11. TITLE (include...Captain, USAF Dh t ibutioni Availabiity Codes Avail adlor Dist [Special December 1986 Approved for public release; distribution...lends itself to the technique of multi -objective analysis. The final step is planning for action. This communicates the entire systems engineering

Lessons Learned through the Development and Publication of AstroImageJ

NASA Astrophysics Data System (ADS)

Collins, Karen

2018-01-01

As lead author of the scientific image processing software package AstroImageJ (AIJ), I will discuss the reasoning behind why we decided to release AIJ to the public, and the lessons we learned related to the development, publication, distribution, and support of AIJ. I will also summarize the AIJ code language selection, code documentation and testing approaches, code distribution, update, and support facilities used, and the code citation and licensing decisions. Since AIJ was initially developed as part of my graduate research and was my first scientific open source software publication, many of my experiences and difficulties encountered may parallel those of others new to scientific software publication. Finally, I will discuss the benefits and disadvantages of releasing scientific software that I now recognize after having AIJ in the public domain for more than five years.

The Numerical Electromagnetics Code (NEC) - A Brief History

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burke, G J; Miller, E K; Poggio, A J

The Numerical Electromagnetics Code, NEC as it is commonly known, continues to be one of the more widely used antenna modeling codes in existence. With several versions in use that reflect different levels of capability and availability, there are now 450 copies of NEC4 and 250 copies of NEC3 that have been distributed by Lawrence Livermore National Laboratory to a limited class of qualified recipients, and several hundred copies of NEC2 that had a recorded distribution by LLNL. These numbers do not account for numerous copies (perhaps 1000s) that were acquired through other means capitalizing on the open source code,more » the absence of distribution controls prior to NEC3 and the availability of versions on the Internet. In this paper we briefly review the history of the code that is concisely displayed in Figure 1. We will show how it capitalized on the research of prominent contributors in the early days of computational electromagnetics, how a combination of events led to the tri-service-supported code development program that ultimately led to NEC and how it evolved to the present day product. The authors apologize that space limitations do not allow us to provide a list of references or to acknowledge the numerous contributors to the code both of which can be found in the code documents.« less

Electromagnetic Fields of a Uniform Sphere in a Uniform Conducting Medium with Application to Dipole Sources

DTIC Science & Technology

1991-09-01

12b. DISTRIBUTION CODE Approved for public release; distribution is unlimited. 13. ABSTRACT (Maximum 200 words) Vector spherical harmonic expansions are...electric and magnetic field vectors from E rand B - r alone. Genural expressions are given relating the scattered field expansion coefficients to the source...Prescnbed by ANSI Std. Z39-18 29W-102 NCSC TR 426-90 CONTENTS Pag o INTRODUCTION 1 BACKGROUND 1 ANGULAR MOMENTUM OPERATOR AND VECTOR SPHERICAL

Multiple description distributed image coding with side information for mobile wireless transmission

NASA Astrophysics Data System (ADS)

Wu, Min; Song, Daewon; Chen, Chang Wen

2005-03-01

Multiple description coding (MDC) is a source coding technique that involves coding the source information into multiple descriptions, and then transmitting them over different channels in packet network or error-prone wireless environment to achieve graceful degradation if parts of descriptions are lost at the receiver. In this paper, we proposed a multiple description distributed wavelet zero tree image coding system for mobile wireless transmission. We provide two innovations to achieve an excellent error resilient capability. First, when MDC is applied to wavelet subband based image coding, it is possible to introduce correlation between the descriptions in each subband. We consider using such a correlation as well as potentially error corrupted description as side information in the decoding to formulate the MDC decoding as a Wyner Ziv decoding problem. If only part of descriptions is lost, however, their correlation information is still available, the proposed Wyner Ziv decoder can recover the description by using the correlation information and the error corrupted description as side information. Secondly, in each description, single bitstream wavelet zero tree coding is very vulnerable to the channel errors. The first bit error may cause the decoder to discard all subsequent bits whether or not the subsequent bits are correctly received. Therefore, we integrate the multiple description scalar quantization (MDSQ) with the multiple wavelet tree image coding method to reduce error propagation. We first group wavelet coefficients into multiple trees according to parent-child relationship and then code them separately by SPIHT algorithm to form multiple bitstreams. Such decomposition is able to reduce error propagation and therefore improve the error correcting capability of Wyner Ziv decoder. Experimental results show that the proposed scheme not only exhibits an excellent error resilient performance but also demonstrates graceful degradation over the packet loss rate.

Support of Multidimensional Parallelism in the OpenMP Programming Model

NASA Technical Reports Server (NTRS)

Jin, Hao-Qiang; Jost, Gabriele

2003-01-01

OpenMP is the current standard for shared-memory programming. While providing ease of parallel programming, the OpenMP programming model also has limitations which often effect the scalability of applications. Examples for these limitations are work distribution and point-to-point synchronization among threads. We propose extensions to the OpenMP programming model which allow the user to easily distribute the work in multiple dimensions and synchronize the workflow among the threads. The proposed extensions include four new constructs and the associated runtime library. They do not require changes to the source code and can be implemented based on the existing OpenMP standard. We illustrate the concept in a prototype translator and test with benchmark codes and a cloud modeling code.

Generation of Mid-Wave Infrared Signature Using Microradiating Devices for Vehicle Mounted Identification Friend or Foe Applications

DTIC Science & Technology

2009-06-01

M. Harkins Approved for public release; distribution is unlimited THIS PAGE INTENTIONALLY LEFT BLANK i REPORT DOCUMENTATION PAGE Form Approved...12a. DISTRIBUTION / AVAILABILITY STATEMENT Approved for public release; distribution is unlimited 12b. DISTRIBUTION CODE 13. ABSTRACT (maximum 200...The integration of a MWIR signature into VMIFF will add a daytime capability. A new generation of compact MWIR sources is emerging to meet demands

Plasma Separation Process: Betacell (BCELL) code: User's manual. [Bipolar barrier junction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taherzadeh, M.

1987-11-13

The emergence of clearly defined applications for (small or large) amounts of long-life and reliable power sources has given the design and production of betavoltaic systems a new life. Moreover, because of the availability of the plasma separation program, (PSP) at TRW, it is now possible to separate the most desirable radioisotopes for betacell power generating devices. A computer code, named BCELL, has been developed to model the betavoltaic concept by utilizing the available up-to-date source/cell parameters. In this program, attempts have been made to determine the betacell energy device maximum efficiency, degradation due to the emitting source radiation andmore » source/cell lifetime power reduction processes. Additionally, comparison is made between the Schottky and PN junction devices for betacell battery design purposes. Certain computer code runs have been made to determine the JV distribution function and the upper limit of the betacell generated power for specified energy sources. A Ni beta emitting radioisotope was used for the energy source and certain semiconductors were used for the converter subsystem of the betacell system. Some results for a Promethium source are also given here for comparison. 16 refs.« less

Open-Source as a strategy for operational software - the case of Enki

NASA Astrophysics Data System (ADS)

Kolberg, Sjur; Bruland, Oddbjørn

2014-05-01

Since 2002, SINTEF Energy has been developing what is now known as the Enki modelling system. This development has been financed by Norway's largest hydropower producer Statkraft, motivated by a desire for distributed hydrological models in operational use. As the owner of the source code, Statkraft has recently decided on Open Source as a strategy for further development, and for migration from an R&D context to operational use. A current cooperation project is currently carried out between SINTEF Energy, 7 large Norwegian hydropower producers including Statkraft, three universities and one software company. Of course, the most immediate task is that of software maturing. A more important challenge, however, is one of gaining experience within the operational hydropower industry. A transition from lumped to distributed models is likely to also require revision of measurement program, calibration strategy, use of GIS and modern data sources like weather radar and satellite imagery. On the other hand, map based visualisations enable a richer information exchange between hydrologic forecasters and power market traders. The operating context of a distributed hydrology model within hydropower planning is far from settled. Being both a modelling framework and a library of plugin-routines to build models from, Enki supports the flexibility needed in this situation. Recent development has separated the core from the user interface, paving the way for a scripting API, cross-platform compilation, and front-end programs serving different degrees of flexibility, robustness and security. The open source strategy invites anyone to use Enki and to develop and contribute new modules. Once tested, the same modules are available for the operational versions of the program. A core challenge is to offer rigid testing procedures and mechanisms to reject routines in an operational setting, without limiting the experimentation with new modules. The Open Source strategy also has implications for building and maintaining competence around the source code and the advanced hydrological and statistical routines in Enki. Originally developed by hydrologists, the Enki code is now approaching a state where maintenance requires a background in professional software development. Without the advantage of proprietary source code, both hydrologic improvements and software maintenance depend on donations or development support on a case-to-case basis, a situation well known within the open source community. It remains to see whether these mechanisms suffice to keep Enki at the maintenance level required by the hydropower sector. ENKI is available from www.opensource-enki.org.

Hybrid digital-analog coding with bandwidth expansion for correlated Gaussian sources under Rayleigh fading

NASA Astrophysics Data System (ADS)

Yahampath, Pradeepa

2017-12-01

Consider communicating a correlated Gaussian source over a Rayleigh fading channel with no knowledge of the channel signal-to-noise ratio (CSNR) at the transmitter. In this case, a digital system cannot be optimal for a range of CSNRs. Analog transmission however is optimal at all CSNRs, if the source and channel are memoryless and bandwidth matched. This paper presents new hybrid digital-analog (HDA) systems for sources with memory and channels with bandwidth expansion, which outperform both digital-only and analog-only systems over a wide range of CSNRs. The digital part is either a predictive quantizer or a transform code, used to achieve a coding gain. Analog part uses linear encoding to transmit the quantization error which improves the performance under CSNR variations. The hybrid encoder is optimized to achieve the minimum AMMSE (average minimum mean square error) over the CSNR distribution. To this end, analytical expressions are derived for the AMMSE of asymptotically optimal systems. It is shown that the outage CSNR of the channel code and the analog-digital power allocation must be jointly optimized to achieve the minimum AMMSE. In the case of HDA predictive quantization, a simple algorithm is presented to solve the optimization problem. Experimental results are presented for both Gauss-Markov sources and speech signals.

Monte Carlo dose calculations in homogeneous media and at interfaces: a comparison between GEPTS, EGSnrc, MCNP, and measurements.

PubMed

Chibani, Omar; Li, X Allen

2002-05-01

Three Monte Carlo photon/electron transport codes (GEPTS, EGSnrc, and MCNP) are bench-marked against dose measurements in homogeneous (both low- and high-Z) media as well as at interfaces. A brief overview on physical models used by each code for photon and electron (positron) transport is given. Absolute calorimetric dose measurements for 0.5 and 1 MeV electron beams incident on homogeneous and multilayer media are compared with the predictions of the three codes. Comparison with dose measurements in two-layer media exposed to a 60Co gamma source is also performed. In addition, comparisons between the codes (including the EGS4 code) are done for (a) 0.05 to 10 MeV electron beams and positron point sources in lead, (b) high-energy photons (10 and 20 MeV) irradiating a multilayer phantom (water/steel/air), and (c) simulation of a 90Sr/90Y brachytherapy source. A good agreement is observed between the calorimetric electron dose measurements and predictions of GEPTS and EGSnrc in both homogeneous and multilayer media. MCNP outputs are found to be dependent on the energy-indexing method (Default/ITS style). This dependence is significant in homogeneous media as well as at interfaces. MCNP(ITS) fits more closely the experimental data than MCNP(DEF), except for the case of Be. At low energy (0.05 and 0.1 MeV), MCNP(ITS) dose distributions in lead show higher maximums in comparison with GEPTS and EGSnrc. EGS4 produces too penetrating electron-dose distributions in high-Z media, especially at low energy (<0.1 MeV). For positrons, differences between GEPTS and EGSnrc are observed in lead because GEPTS distinguishes positrons from electrons for both elastic multiple scattering and bremsstrahlung emission models. For the 60Co source, a quite good agreement between calculations and measurements is observed with regards to the experimental uncertainty. For the other cases (10 and 20 MeV photon sources and the 90Sr/90Y beta source), a good agreement is found between the three codes. In conclusion, differences between GEPTS and EGSnrc results are found to be very small for almost all media and energies studied. MCNP results depend significantly on the electron energy-indexing method.

The Fast Scattering Code (FSC): Validation Studies and Program Guidelines

NASA Technical Reports Server (NTRS)

Tinetti, Ana F.; Dunn, Mark H.

2011-01-01

The Fast Scattering Code (FSC) is a frequency domain noise prediction program developed at the NASA Langley Research Center (LaRC) to simulate the acoustic field produced by the interaction of known, time harmonic incident sound with bodies of arbitrary shape and surface impedance immersed in a potential flow. The code uses the equivalent source method (ESM) to solve an exterior 3-D Helmholtz boundary value problem (BVP) by expanding the scattered acoustic pressure field into a series of point sources distributed on a fictitious surface placed inside the actual scatterer. This work provides additional code validation studies and illustrates the range of code parameters that produce accurate results with minimal computational costs. Systematic noise prediction studies are presented in which monopole generated incident sound is scattered by simple geometric shapes - spheres (acoustically hard and soft surfaces), oblate spheroids, flat disk, and flat plates with various edge topologies. Comparisons between FSC simulations and analytical results and experimental data are presented.

On the optimality of a universal noiseless coder

NASA Technical Reports Server (NTRS)

Yeh, Pen-Shu; Rice, Robert F.; Miller, Warner H.

1993-01-01

Rice developed a universal noiseless coding structure that provides efficient performance over an extremely broad range of source entropy. This is accomplished by adaptively selecting the best of several easily implemented variable length coding algorithms. Variations of such noiseless coders have been used in many NASA applications. Custom VLSI coder and decoder modules capable of processing over 50 million samples per second have been fabricated and tested. In this study, the first of the code options used in this module development is shown to be equivalent to a class of Huffman code under the Humblet condition, for source symbol sets having a Laplacian distribution. Except for the default option, other options are shown to be equivalent to the Huffman codes of a modified Laplacian symbol set, at specified symbol entropy values. Simulation results are obtained on actual aerial imagery over a wide entropy range, and they confirm the optimality of the scheme. Comparison with other known techniques are performed on several widely used images and the results further validate the coder's optimality.

Spatial correlation-based side information refinement for distributed video coding

NASA Astrophysics Data System (ADS)

Taieb, Mohamed Haj; Chouinard, Jean-Yves; Wang, Demin

2013-12-01

Distributed video coding (DVC) architecture designs, based on distributed source coding principles, have benefitted from significant progresses lately, notably in terms of achievable rate-distortion performances. However, a significant performance gap still remains when compared to prediction-based video coding schemes such as H.264/AVC. This is mainly due to the non-ideal exploitation of the video sequence temporal correlation properties during the generation of side information (SI). In fact, the decoder side motion estimation provides only an approximation of the true motion. In this paper, a progressive DVC architecture is proposed, which exploits the spatial correlation of the video frames to improve the motion-compensated temporal interpolation (MCTI). Specifically, Wyner-Ziv (WZ) frames are divided into several spatially correlated groups that are then sent progressively to the receiver. SI refinement (SIR) is performed as long as these groups are being decoded, thus providing more accurate SI for the next groups. It is shown that the proposed progressive SIR method leads to significant improvements over the Discover DVC codec as well as other SIR schemes recently introduced in the literature.

Automatic Data Traffic Control on DSM Architecture

NASA Technical Reports Server (NTRS)

Frumkin, Michael; Jin, Hao-Qiang; Yan, Jerry; Kwak, Dochan (Technical Monitor)

2000-01-01

We study data traffic on distributed shared memory machines and conclude that data placement and grouping improve performance of scientific codes. We present several methods which user can employ to improve data traffic in his code. We report on implementation of a tool which detects the code fragments causing data congestions and advises user on improvements of data routing in these fragments. The capabilities of the tool include deduction of data alignment and affinity from the source code; detection of the code constructs having abnormally high cache or TLB misses; generation of data placement constructs. We demonstrate the capabilities of the tool on experiments with NAS parallel benchmarks and with a simple computational fluid dynamics application ARC3D.

TRIQS: A toolbox for research on interacting quantum systems

NASA Astrophysics Data System (ADS)

Parcollet, Olivier; Ferrero, Michel; Ayral, Thomas; Hafermann, Hartmut; Krivenko, Igor; Messio, Laura; Seth, Priyanka

2015-11-01

We present the TRIQS library, a Toolbox for Research on Interacting Quantum Systems. It is an open-source, computational physics library providing a framework for the quick development of applications in the field of many-body quantum physics, and in particular, strongly-correlated electronic systems. It supplies components to develop codes in a modern, concise and efficient way: e.g. Green's function containers, a generic Monte Carlo class, and simple interfaces to HDF5. TRIQS is a C++/Python library that can be used from either language. It is distributed under the GNU General Public License (GPLv3). State-of-the-art applications based on the library, such as modern quantum many-body solvers and interfaces between density-functional-theory codes and dynamical mean-field theory (DMFT) codes are distributed along with it.

An Infrastructure for UML-Based Code Generation Tools

NASA Astrophysics Data System (ADS)

Wehrmeister, Marco A.; Freitas, Edison P.; Pereira, Carlos E.

The use of Model-Driven Engineering (MDE) techniques in the domain of distributed embedded real-time systems are gain importance in order to cope with the increasing design complexity of such systems. This paper discusses an infrastructure created to build GenERTiCA, a flexible tool that supports a MDE approach, which uses aspect-oriented concepts to handle non-functional requirements from embedded and real-time systems domain. GenERTiCA generates source code from UML models, and also performs weaving of aspects, which have been specified within the UML model. Additionally, this paper discusses the Distributed Embedded Real-Time Compact Specification (DERCS), a PIM created to support UML-based code generation tools. Some heuristics to transform UML models into DERCS, which have been implemented in GenERTiCA, are also discussed.

On the effect of updated MCNP photon cross section data on the simulated response of the HPA TLD.

PubMed

Eakins, Jonathan

2009-02-01

The relative response of the new Health Protection Agency thermoluminescence dosimeter (TLD) has been calculated for Narrow Series X-ray distribution and (137)Cs photon sources using the Monte Carlo code MCNP5, and the results compared with those obtained during its design stage using the predecessor code, MCNP4c2. The results agreed at intermediate energies (approximately 0.1 MeV to (137)Cs), but differed at low energies (<0.1 MeV) by up to approximately 10%. This disparity has been ascribed to differences in the default photon interaction data used by the two codes, and derives ultimately from the effect on absorbed dose of the recent updates to the photoelectric cross sections. The sources of these data have been reviewed.

Evaluation of coded aperture radiation detectors using a Bayesian approach

NASA Astrophysics Data System (ADS)

Miller, Kyle; Huggins, Peter; Labov, Simon; Nelson, Karl; Dubrawski, Artur

2016-12-01

We investigate tradeoffs arising from the use of coded aperture gamma-ray spectrometry to detect and localize sources of harmful radiation in the presence of noisy background. Using an example application scenario of area monitoring and search, we empirically evaluate weakly supervised spectral, spatial, and hybrid spatio-spectral algorithms for scoring individual observations, and two alternative methods of fusing evidence obtained from multiple observations. Results of our experiments confirm the intuition that directional information provided by spectrometers masked with coded aperture enables gains in source localization accuracy, but at the expense of reduced probability of detection. Losses in detection performance can however be to a substantial extent reclaimed by using our new spatial and spatio-spectral scoring methods which rely on realistic assumptions regarding masking and its impact on measured photon distributions.

Recent skyshine calculations at Jefferson Lab

DOE Office of Scientific and Technical Information (OSTI.GOV)

Degtyarenko, P.

1997-12-01

New calculations of the skyshine dose distribution of neutrons and secondary photons have been performed at Jefferson Lab using the Monte Carlo method. The dose dependence on neutron energy, distance to the neutron source, polar angle of a source neutron, and azimuthal angle between the observation point and the momentum direction of a source neutron have been studied. The azimuthally asymmetric term in the skyshine dose distribution is shown to be important in the dose calculations around high-energy accelerator facilities. A parameterization formula and corresponding computer code have been developed which can be used for detailed calculations of the skyshinemore » dose maps.« less

A new software for deformation source optimization, the Bayesian Earthquake Analysis Tool (BEAT)

NASA Astrophysics Data System (ADS)

Vasyura-Bathke, H.; Dutta, R.; Jonsson, S.; Mai, P. M.

2017-12-01

Modern studies of crustal deformation and the related source estimation, including magmatic and tectonic sources, increasingly use non-linear optimization strategies to estimate geometric and/or kinematic source parameters and often consider both jointly, geodetic and seismic data. Bayesian inference is increasingly being used for estimating posterior distributions of deformation source model parameters, given measured/estimated/assumed data and model uncertainties. For instance, some studies consider uncertainties of a layered medium and propagate these into source parameter uncertainties, while others use informative priors to reduce the model parameter space. In addition, innovative sampling algorithms have been developed to efficiently explore the high-dimensional parameter spaces. Compared to earlier studies, these improvements have resulted in overall more robust source model parameter estimates that include uncertainties. However, the computational burden of these methods is high and estimation codes are rarely made available along with the published results. Even if the codes are accessible, it is usually challenging to assemble them into a single optimization framework as they are typically coded in different programing languages. Therefore, further progress and future applications of these methods/codes are hampered, while reproducibility and validation of results has become essentially impossible. In the spirit of providing open-access and modular codes to facilitate progress and reproducible research in deformation source estimations, we undertook the effort of developing BEAT, a python package that comprises all the above-mentioned features in one single programing environment. The package builds on the pyrocko seismological toolbox (www.pyrocko.org), and uses the pymc3 module for Bayesian statistical model fitting. BEAT is an open-source package (https://github.com/hvasbath/beat), and we encourage and solicit contributions to the project. Here, we present our strategy for developing BEAT and show application examples; especially the effect of including the model prediction uncertainty of the velocity model in following source optimizations: full moment tensor, Mogi source, moderate strike-slip earth-quake.

Software Engineering Laboratory (SEL) data and information policy

NASA Technical Reports Server (NTRS)

Mcgarry, Frank

1991-01-01

The policies and overall procedures that are used in distributing and in making available products of the Software Engineering Laboratory (SEL) are discussed. The products include project data and measures, project source code, reports, and software tools.

Versatile fusion source integrator AFSI for fast ion and neutron studies in fusion devices

NASA Astrophysics Data System (ADS)

Sirén, Paula; Varje, Jari; Äkäslompolo, Simppa; Asunta, Otto; Giroud, Carine; Kurki-Suonio, Taina; Weisen, Henri; JET Contributors, The

2018-01-01

ASCOT Fusion Source Integrator AFSI, an efficient tool for calculating fusion reaction rates and characterizing the fusion products, based on arbitrary reactant distributions, has been developed and is reported in this paper. Calculation of reactor-relevant D-D, D-T and D-3He fusion reactions has been implemented based on the Bosch-Hale fusion cross sections. The reactions can be calculated between arbitrary particle populations, including Maxwellian thermal particles and minority energetic particles. Reaction rate profiles, energy spectra and full 4D phase space distributions can be calculated for the non-isotropic reaction products. The code is especially suitable for integrated modelling in self-consistent plasma physics simulations as well as in the Serpent neutronics calculation chain. Validation of the model has been performed for neutron measurements at the JET tokamak and the code has been applied to predictive simulations in ITER.

NPTFit: A Code Package for Non-Poissonian Template Fitting

NASA Astrophysics Data System (ADS)

Mishra-Sharma, Siddharth; Rodd, Nicholas L.; Safdi, Benjamin R.

2017-06-01

We present NPTFit, an open-source code package, written in Python and Cython, for performing non-Poissonian template fits (NPTFs). The NPTF is a recently developed statistical procedure for characterizing the contribution of unresolved point sources (PSs) to astrophysical data sets. The NPTF was first applied to Fermi gamma-ray data to provide evidence that the excess of ˜GeV gamma-rays observed in the inner regions of the Milky Way likely arises from a population of sub-threshold point sources, and the NPTF has since found additional applications studying sub-threshold extragalactic sources at high Galactic latitudes. The NPTF generalizes traditional astrophysical template fits to allow for the ability to search for populations of unresolved PSs that may follow a given spatial distribution. NPTFit builds upon the framework of the fluctuation analyses developed in X-ray astronomy, thus it likely has applications beyond those demonstrated with gamma-ray data. The NPTFit package utilizes novel computational methods to perform the NPTF efficiently. The code is available at http://github.com/bsafdi/NPTFit and up-to-date and extensive documentation may be found at http://nptfit.readthedocs.io.

A methodology for efficiency optimization of betavoltaic cell design using an isotropic planar source having an energy dependent beta particle distribution.

PubMed

Theirrattanakul, Sirichai; Prelas, Mark

2017-09-01

Nuclear batteries based on silicon carbide betavoltaic cells have been studied extensively in the literature. This paper describes an analysis of design parameters, which can be applied to a variety of materials, but is specific to silicon carbide. In order to optimize the interface between a beta source and silicon carbide p-n junction, it is important to account for the specific isotope, angular distribution of the beta particles from the source, the energy distribution of the source as well as the geometrical aspects of the interface between the source and the transducer. In this work, both the angular distribution and energy distribution of the beta particles are modeled using a thin planar beta source (e.g., H-3, Ni-63, S-35, Pm-147, Sr-90, and Y-90) with GEANT4. Previous studies of betavoltaics with various source isotopes have shown that Monte Carlo based codes such as MCNPX, GEANT4 and Penelope generate similar results. GEANT4 is chosen because it has important strengths for the treatment of electron energies below one keV and it is widely available. The model demonstrates the effects of angular distribution, the maximum energy of the beta particle and energy distribution of the beta source on the betavoltaic and it is useful in determining the spatial profile of the power deposition in the cell. Copyright © 2017. Published by Elsevier Ltd.

Jet Measurements for Development of Jet Noise Prediction Tools

NASA Technical Reports Server (NTRS)

Bridges, James E.

2006-01-01

The primary focus of my presentation is the development of the jet noise prediction code JeNo with most examples coming from the experimental work that drove the theoretical development and validation. JeNo is a statistical jet noise prediction code, based upon the Lilley acoustic analogy. Our approach uses time-average 2-D or 3-D mean and turbulent statistics of the flow as input. The output is source distributions and spectral directivity.

Open source clustering software.

PubMed

de Hoon, M J L; Imoto, S; Nolan, J; Miyano, S

2004-06-12

We have implemented k-means clustering, hierarchical clustering and self-organizing maps in a single multipurpose open-source library of C routines, callable from other C and C++ programs. Using this library, we have created an improved version of Michael Eisen's well-known Cluster program for Windows, Mac OS X and Linux/Unix. In addition, we generated a Python and a Perl interface to the C Clustering Library, thereby combining the flexibility of a scripting language with the speed of C. The C Clustering Library and the corresponding Python C extension module Pycluster were released under the Python License, while the Perl module Algorithm::Cluster was released under the Artistic License. The GUI code Cluster 3.0 for Windows, Macintosh and Linux/Unix, as well as the corresponding command-line program, were released under the same license as the original Cluster code. The complete source code is available at http://bonsai.ims.u-tokyo.ac.jp/mdehoon/software/cluster. Alternatively, Algorithm::Cluster can be downloaded from CPAN, while Pycluster is also available as part of the Biopython distribution.

GAMSOR: Gamma Source Preparation and DIF3D Flux Solution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, M. A.; Lee, C. H.; Hill, R. N.

2016-12-15

Nuclear reactors that rely upon the fission reaction have two modes of thermal energy deposition in the reactor system: neutron absorption and gamma absorption. The gamma rays are typically generated by neutron absorption reactions or during the fission process which means the primary driver of energy production is of course the neutron interaction. In conventional reactor physics methods, the gamma heating component is ignored such that the gamma absorption is forced to occur at the gamma emission site. For experimental reactor systems like EBR-II and FFTF, the placement of structural pins and assemblies internal to the core leads to problemsmore » with power heating predictions because there is no fission power source internal to the assembly to dictate a spatial distribution of the power. As part of the EBR-II support work in the 1980s, the GAMSOR code was developed to assist analysts in calculating the gamma heating. The GAMSOR code is a modified version of DIF3D and actually functions within a sequence of DIF3D calculations. The gamma flux in a conventional fission reactor system does not perturb the neutron flux and thus the gamma flux calculation can be cast as a fixed source problem given a solution to the steady state neutron flux equation. This leads to a sequence of DIF3D calculations, called the GAMSOR sequence, which involves solving the neutron flux, then the gamma flux, then combining the results to do a summary edit. In this manuscript, we go over the GAMSOR code and detail how it is put together and functions. We also discuss how to setup the GAMSOR sequence and input for each DIF3D calculation in the GAMSOR sequence. With the GAMSOR capability, users can take any valid steady state DIF3D calculation and compute the power distribution due to neutron and gamma heating. The MC2-3 code is the preferable companion code to use for generating neutron and gamma cross section data, but the GAMSOR code can accept cross section data from other sources. To further this aspect, an additional utility code was created which demonstrates how to merge the neutron and gamma cross section data together to carry out a simultaneous solve of the two systems.« less

WARP

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bergmann, Ryan M.; Rowland, Kelly L.

2017-04-12

WARP, which can stand for ``Weaving All the Random Particles,'' is a three-dimensional (3D) continuous energy Monte Carlo neutron transport code developed at UC Berkeley to efficiently execute on NVIDIA graphics processing unit (GPU) platforms. WARP accelerates Monte Carlo simulations while preserving the benefits of using the Monte Carlo method, namely, that very few physical and geometrical simplifications are applied. WARP is able to calculate multiplication factors, neutron flux distributions (in both space and energy), and fission source distributions for time-independent neutron transport problems. It can run in both criticality or fixed source modes, but fixed source mode is currentlymore » not robust, optimized, or maintained in the newest version. WARP can transport neutrons in unrestricted arrangements of parallelepipeds, hexagonal prisms, cylinders, and spheres. The goal of developing WARP is to investigate algorithms that can grow into a full-featured, continuous energy, Monte Carlo neutron transport code that is accelerated by running on GPUs. The crux of the effort is to make Monte Carlo calculations faster while producing accurate results. Modern supercomputers are commonly being built with GPU coprocessor cards in their nodes to increase their computational efficiency and performance. GPUs execute efficiently on data-parallel problems, but most CPU codes, including those for Monte Carlo neutral particle transport, are predominantly task-parallel. WARP uses a data-parallel neutron transport algorithm to take advantage of the computing power GPUs offer.« less

NPS-NRL-Rice-UIUC Collaboration on Navy Atmosphere-Ocean Coupled Models on Many-Core Computer Architectures Annual Report

DTIC Science & Technology

2015-09-30

DISTRIBUTION STATEMENT A: Distribution approved for public release; distribution is unlimited. NPS-NRL- Rice -UIUC Collaboration on Navy Atmosphere...portability. There is still a gap in the OCCA support for Fortran programmers who do not have accelerator experience. Activities at Rice /Virginia Tech are...for automated data movement and for kernel optimization using source code analysis and run-time detective work. In this quarter the Rice /Virginia

Simulating of the measurement-device independent quantum key distribution with phase randomized general sources

PubMed Central

Wang, Qin; Wang, Xiang-Bin

2014-01-01

We present a model on the simulation of the measurement-device independent quantum key distribution (MDI-QKD) with phase randomized general sources. It can be used to predict experimental observations of a MDI-QKD with linear channel loss, simulating corresponding values for the gains, the error rates in different basis, and also the final key rates. Our model can be applicable to the MDI-QKDs with arbitrary probabilistic mixture of different photon states or using any coding schemes. Therefore, it is useful in characterizing and evaluating the performance of the MDI-QKD protocol, making it a valuable tool in studying the quantum key distributions. PMID:24728000

Fall 2014 SEI Research Review Edge-Enabled Tactical Systems (EETS)

DTIC Science & Technology

2014-10-29

Effective communicate and reasoning despite connectivity issues • More generally, how to make programming distributed algorithms with extensible...distributed collaboration in VREP simulations for 5-12 quadcopters and ground robots • Open-source middleware and algorithms released to community...Integration into CMU Drone-RK quadcopter and Platypus autonomous boat platforms • Presentations at DARPA (CODE), AFRL C4I Workshop, and AFRL Eglin

JavaGenes Molecular Evolution

NASA Technical Reports Server (NTRS)

Lohn, Jason; Smith, David; Frank, Jeremy; Globus, Al; Crawford, James

2007-01-01

JavaGenes is a general-purpose, evolutionary software system written in Java. It implements several versions of a genetic algorithm, simulated annealing, stochastic hill climbing, and other search techniques. This software has been used to evolve molecules, atomic force field parameters, digital circuits, Earth Observing Satellite schedules, and antennas. This version differs from version 0.7.28 in that it includes the molecule evolution code and other improvements. Except for the antenna code, JaveGenes is available for NASA Open Source distribution.

Spiral computed tomography phase-space source model in the BEAMnrc/EGSnrc Monte Carlo system: implementation and validation.

PubMed

Kim, Sangroh; Yoshizumi, Terry T; Yin, Fang-Fang; Chetty, Indrin J

2013-04-21

Currently, the BEAMnrc/EGSnrc Monte Carlo (MC) system does not provide a spiral CT source model for the simulation of spiral CT scanning. We developed and validated a spiral CT phase-space source model in the BEAMnrc/EGSnrc system. The spiral phase-space source model was implemented in the DOSXYZnrc user code of the BEAMnrc/EGSnrc system by analyzing the geometry of spiral CT scan-scan range, initial angle, rotational direction, pitch, slice thickness, etc. Table movement was simulated by changing the coordinates of the isocenter as a function of beam angles. Some parameters such as pitch, slice thickness and translation per rotation were also incorporated into the model to make the new phase-space source model, designed specifically for spiral CT scan simulations. The source model was hard-coded by modifying the 'ISource = 8: Phase-Space Source Incident from Multiple Directions' in the srcxyznrc.mortran and dosxyznrc.mortran files in the DOSXYZnrc user code. In order to verify the implementation, spiral CT scans were simulated in a CT dose index phantom using the validated x-ray tube model of a commercial CT simulator for both the original multi-direction source (ISOURCE = 8) and the new phase-space source model in the DOSXYZnrc system. Then the acquired 2D and 3D dose distributions were analyzed with respect to the input parameters for various pitch values. In addition, surface-dose profiles were also measured for a patient CT scan protocol using radiochromic film and were compared with the MC simulations. The new phase-space source model was found to simulate the spiral CT scanning in a single simulation run accurately. It also produced the equivalent dose distribution of the ISOURCE = 8 model for the same CT scan parameters. The MC-simulated surface profiles were well matched to the film measurement overall within 10%. The new spiral CT phase-space source model was implemented in the BEAMnrc/EGSnrc system. This work will be beneficial in estimating the spiral CT scan dose in the BEAMnrc/EGSnrc system.

Spiral computed tomography phase-space source model in the BEAMnrc/EGSnrc Monte Carlo system: implementation and validation

NASA Astrophysics Data System (ADS)

Kim, Sangroh; Yoshizumi, Terry T.; Yin, Fang-Fang; Chetty, Indrin J.

2013-04-01

Currently, the BEAMnrc/EGSnrc Monte Carlo (MC) system does not provide a spiral CT source model for the simulation of spiral CT scanning. We developed and validated a spiral CT phase-space source model in the BEAMnrc/EGSnrc system. The spiral phase-space source model was implemented in the DOSXYZnrc user code of the BEAMnrc/EGSnrc system by analyzing the geometry of spiral CT scan—scan range, initial angle, rotational direction, pitch, slice thickness, etc. Table movement was simulated by changing the coordinates of the isocenter as a function of beam angles. Some parameters such as pitch, slice thickness and translation per rotation were also incorporated into the model to make the new phase-space source model, designed specifically for spiral CT scan simulations. The source model was hard-coded by modifying the ‘ISource = 8: Phase-Space Source Incident from Multiple Directions’ in the srcxyznrc.mortran and dosxyznrc.mortran files in the DOSXYZnrc user code. In order to verify the implementation, spiral CT scans were simulated in a CT dose index phantom using the validated x-ray tube model of a commercial CT simulator for both the original multi-direction source (ISOURCE = 8) and the new phase-space source model in the DOSXYZnrc system. Then the acquired 2D and 3D dose distributions were analyzed with respect to the input parameters for various pitch values. In addition, surface-dose profiles were also measured for a patient CT scan protocol using radiochromic film and were compared with the MC simulations. The new phase-space source model was found to simulate the spiral CT scanning in a single simulation run accurately. It also produced the equivalent dose distribution of the ISOURCE = 8 model for the same CT scan parameters. The MC-simulated surface profiles were well matched to the film measurement overall within 10%. The new spiral CT phase-space source model was implemented in the BEAMnrc/EGSnrc system. This work will be beneficial in estimating the spiral CT scan dose in the BEAMnrc/EGSnrc system.

Impurity mixing and radiation asymmetry in massive gas injection simulations of DIII-D

DOE Office of Scientific and Technical Information (OSTI.GOV)

Izzo, V. A.

Simulations of neon massive gas injection into DIII-D are performed with the 3D MHD code NIMROD. The poloidal and toroidal distribution of the impurity source is varied. This report will focus on the effects of the source variation on impurity mixing and radiated power asymmetry. Even toroidally symmetric impurity injection is found to produce asymmetric radiated power due to asymmetric convective heat flux produced by the 1/1 mode. When the gas source is toroidally localized, the phase relationship between the mode and the source location is important, affecting both radiation peaking and impurity mixing. Under certain circumstances, a single, localizedmore » gas jet could produce better radiation symmetry during the disruption thermal quench than evenly distributed impurities.« less

JADAMILU: a software code for computing selected eigenvalues of large sparse symmetric matrices

NASA Astrophysics Data System (ADS)

Bollhöfer, Matthias; Notay, Yvan

2007-12-01

A new software code for computing selected eigenvalues and associated eigenvectors of a real symmetric matrix is described. The eigenvalues are either the smallest or those closest to some specified target, which may be in the interior of the spectrum. The underlying algorithm combines the Jacobi-Davidson method with efficient multilevel incomplete LU (ILU) preconditioning. Key features are modest memory requirements and robust convergence to accurate solutions. Parameters needed for incomplete LU preconditioning are automatically computed and may be updated at run time depending on the convergence pattern. The software is easy to use by non-experts and its top level routines are written in FORTRAN 77. Its potentialities are demonstrated on a few applications taken from computational physics. Program summaryProgram title: JADAMILU Catalogue identifier: ADZT_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADZT_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 101 359 No. of bytes in distributed program, including test data, etc.: 7 493 144 Distribution format: tar.gz Programming language: Fortran 77 Computer: Intel or AMD with g77 and pgf; Intel EM64T or Itanium with ifort; AMD Opteron with g77, pgf and ifort; Power (IBM) with xlf90. Operating system: Linux, AIX RAM: problem dependent Word size: real:8; integer: 4 or 8, according to user's choice Classification: 4.8 Nature of problem: Any physical problem requiring the computation of a few eigenvalues of a symmetric matrix. Solution method: Jacobi-Davidson combined with multilevel ILU preconditioning. Additional comments: We supply binaries rather than source code because JADAMILU uses the following external packages: MC64. This software is copyrighted software and not freely available. COPYRIGHT (c) 1999 Council for the Central Laboratory of the Research Councils. AMD. Copyright (c) 2004-2006 by Timothy A. Davis, Patrick R. Amestoy, and Iain S. Duff. Source code is distributed by the authors under the GNU LGPL licence. BLAS. The reference BLAS is a freely-available software package. It is available from netlib via anonymous ftp and the World Wide Web. LAPACK. The complete LAPACK package or individual routines from LAPACK are freely available on netlib and can be obtained via the World Wide Web or anonymous ftp. For maximal benefit to the community, we added the sources we are proprietary of to the tar.gz file submitted for inclusion in the CPC library. However, as explained in the README file, users willing to compile the code instead of using binaries should first obtain the sources for the external packages mentioned above (email and/or web addresses are provided). Running time: Problem dependent; the test examples provided with the code only take a few seconds to run; timing results for large scale problems are given in Section 5.

Source Term Model for Steady Micro Jets in a Navier-Stokes Computer Code

NASA Technical Reports Server (NTRS)

Waithe, Kenrick A.

2005-01-01

A source term model for steady micro jets was implemented into a non-proprietary Navier-Stokes computer code, OVERFLOW. The source term models the mass flow and momentum created by a steady blowing micro jet. The model is obtained by adding the momentum and mass flow created by the jet to the Navier-Stokes equations. The model was tested by comparing with data from numerical simulations of a single, steady micro jet on a flat plate in two and three dimensions. The source term model predicted the velocity distribution well compared to the two-dimensional plate using a steady mass flow boundary condition, which was used to simulate a steady micro jet. The model was also compared to two three-dimensional flat plate cases using a steady mass flow boundary condition to simulate a steady micro jet. The three-dimensional comparison included a case with a grid generated to capture the circular shape of the jet and a case without a grid generated for the micro jet. The case without the jet grid mimics the application of the source term. The source term model compared well with both of the three-dimensional cases. Comparisons of velocity distribution were made before and after the jet and Mach and vorticity contours were examined. The source term model allows a researcher to quickly investigate different locations of individual or several steady micro jets. The researcher is able to conduct a preliminary investigation with minimal grid generation and computational time.

OFF, Open source Finite volume Fluid dynamics code: A free, high-order solver based on parallel, modular, object-oriented Fortran API

NASA Astrophysics Data System (ADS)

Zaghi, S.

2014-07-01

OFF, an open source (free software) code for performing fluid dynamics simulations, is presented. The aim of OFF is to solve, numerically, the unsteady (and steady) compressible Navier-Stokes equations of fluid dynamics by means of finite volume techniques: the research background is mainly focused on high-order (WENO) schemes for multi-fluids, multi-phase flows over complex geometries. To this purpose a highly modular, object-oriented application program interface (API) has been developed. In particular, the concepts of data encapsulation and inheritance available within Fortran language (from standard 2003) have been stressed in order to represent each fluid dynamics "entity" (e.g. the conservative variables of a finite volume, its geometry, etc…) by a single object so that a large variety of computational libraries can be easily (and efficiently) developed upon these objects. The main features of OFF can be summarized as follows: Programming LanguageOFF is written in standard (compliant) Fortran 2003; its design is highly modular in order to enhance simplicity of use and maintenance without compromising the efficiency; Parallel Frameworks Supported the development of OFF has been also targeted to maximize the computational efficiency: the code is designed to run on shared-memory multi-cores workstations and distributed-memory clusters of shared-memory nodes (supercomputers); the code's parallelization is based on Open Multiprocessing (OpenMP) and Message Passing Interface (MPI) paradigms; Usability, Maintenance and Enhancement in order to improve the usability, maintenance and enhancement of the code also the documentation has been carefully taken into account; the documentation is built upon comprehensive comments placed directly into the source files (no external documentation files needed): these comments are parsed by means of doxygen free software producing high quality html and latex documentation pages; the distributed versioning system referred as git has been adopted in order to facilitate the collaborative maintenance and improvement of the code; CopyrightsOFF is a free software that anyone can use, copy, distribute, study, change and improve under the GNU Public License version 3. The present paper is a manifesto of OFF code and presents the currently implemented features and ongoing developments. This work is focused on the computational techniques adopted and a detailed description of the main API characteristics is reported. OFF capabilities are demonstrated by means of one and two dimensional examples and a three dimensional real application.

Improved neutron activation prediction code system development

NASA Technical Reports Server (NTRS)

Saqui, R. M.

1971-01-01

Two integrated neutron activation prediction code systems have been developed by modifying and integrating existing computer programs to perform the necessary computations to determine neutron induced activation gamma ray doses and dose rates in complex geometries. Each of the two systems is comprised of three computational modules. The first program module computes the spatial and energy distribution of the neutron flux from an input source and prepares input data for the second program which performs the reaction rate, decay chain and activation gamma source calculations. A third module then accepts input prepared by the second program to compute the cumulative gamma doses and/or dose rates at specified detector locations in complex, three-dimensional geometries.

The TORSED method for construction of TORT boundary sources from external DORT flux files

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rhoades, W.A.

1993-08-01

The TORSED method provides a means of coupling cylindrical two-dimensional DORT fluxes or fluences to a three-dimensional TORT calculation in Cartesian geometry through construction of external boundary sources for TORT. This can be important for several reasons. The two-dimensional environment may be too large for TORT simulation. The two-dimensional environment may be truly cylindrical in nature, and thus, better treated in that geometry. It may be desired to use a single environment calculation to study numerous local perturbations. In Section I the TORSED code is described in detail and the diverse demonstration problems that accompany the code distribution are discussed.more » In Section II, an updated discussion of the VISA code is given. VISA is required to preprocess the DORT files for use in TORSED. In Section III, the references are listed.« less

Fast GPU-based Monte Carlo simulations for LDR prostate brachytherapy.

PubMed

Bonenfant, Éric; Magnoux, Vincent; Hissoiny, Sami; Ozell, Benoît; Beaulieu, Luc; Després, Philippe

2015-07-07

The aim of this study was to evaluate the potential of bGPUMCD, a Monte Carlo algorithm executed on Graphics Processing Units (GPUs), for fast dose calculations in permanent prostate implant dosimetry. It also aimed to validate a low dose rate brachytherapy source in terms of TG-43 metrics and to use this source to compute dose distributions for permanent prostate implant in very short times. The physics of bGPUMCD was reviewed and extended to include Rayleigh scattering and fluorescence from photoelectric interactions for all materials involved. The radial and anisotropy functions were obtained for the Nucletron SelectSeed in TG-43 conditions. These functions were compared to those found in the MD Anderson Imaging and Radiation Oncology Core brachytherapy source registry which are considered the TG-43 reference values. After appropriate calibration of the source, permanent prostate implant dose distributions were calculated for four patients and compared to an already validated Geant4 algorithm. The radial function calculated from bGPUMCD showed excellent agreement (differences within 1.3%) with TG-43 accepted values. The anisotropy functions at r = 1 cm and r = 4 cm were within 2% of TG-43 values for angles over 17.5°. For permanent prostate implants, Monte Carlo-based dose distributions with a statistical uncertainty of 1% or less for the target volume were obtained in 30 s or less for 1 × 1 × 1 mm(3) calculation grids. Dosimetric indices were very similar (within 2.7%) to those obtained with a validated, independent Monte Carlo code (Geant4) performing the calculations for the same cases in a much longer time (tens of minutes to more than a hour). bGPUMCD is a promising code that lets envision the use of Monte Carlo techniques in a clinical environment, with sub-minute execution times on a standard workstation. Future work will explore the use of this code with an inverse planning method to provide a complete Monte Carlo-based planning solution.

Fast GPU-based Monte Carlo simulations for LDR prostate brachytherapy

NASA Astrophysics Data System (ADS)

Bonenfant, Éric; Magnoux, Vincent; Hissoiny, Sami; Ozell, Benoît; Beaulieu, Luc; Després, Philippe

2015-07-01

The aim of this study was to evaluate the potential of bGPUMCD, a Monte Carlo algorithm executed on Graphics Processing Units (GPUs), for fast dose calculations in permanent prostate implant dosimetry. It also aimed to validate a low dose rate brachytherapy source in terms of TG-43 metrics and to use this source to compute dose distributions for permanent prostate implant in very short times. The physics of bGPUMCD was reviewed and extended to include Rayleigh scattering and fluorescence from photoelectric interactions for all materials involved. The radial and anisotropy functions were obtained for the Nucletron SelectSeed in TG-43 conditions. These functions were compared to those found in the MD Anderson Imaging and Radiation Oncology Core brachytherapy source registry which are considered the TG-43 reference values. After appropriate calibration of the source, permanent prostate implant dose distributions were calculated for four patients and compared to an already validated Geant4 algorithm. The radial function calculated from bGPUMCD showed excellent agreement (differences within 1.3%) with TG-43 accepted values. The anisotropy functions at r = 1 cm and r = 4 cm were within 2% of TG-43 values for angles over 17.5°. For permanent prostate implants, Monte Carlo-based dose distributions with a statistical uncertainty of 1% or less for the target volume were obtained in 30 s or less for 1 × 1 × 1 mm3 calculation grids. Dosimetric indices were very similar (within 2.7%) to those obtained with a validated, independent Monte Carlo code (Geant4) performing the calculations for the same cases in a much longer time (tens of minutes to more than a hour). bGPUMCD is a promising code that lets envision the use of Monte Carlo techniques in a clinical environment, with sub-minute execution times on a standard workstation. Future work will explore the use of this code with an inverse planning method to provide a complete Monte Carlo-based planning solution.

Recent Simulation Results on Ring Current Dynamics Using the Comprehensive Ring Current Model

NASA Technical Reports Server (NTRS)

Zheng, Yihua; Zaharia, Sorin G.; Lui, Anthony T. Y.; Fok, Mei-Ching

2010-01-01

Plasma sheet conditions and electromagnetic field configurations are both crucial in determining ring current evolution and connection to the ionosphere. In this presentation, we investigate how different conditions of plasma sheet distribution affect ring current properties. Results include comparative studies in 1) varying the radial distance of the plasma sheet boundary; 2) varying local time distribution of the source population; 3) varying the source spectra. Our results show that a source located farther away leads to a stronger ring current than a source that is closer to the Earth. Local time distribution of the source plays an important role in determining both the radial and azimuthal (local time) location of the ring current peak pressure. We found that post-midnight source locations generally lead to a stronger ring current. This finding is in agreement with Lavraud et al.. However, our results do not exhibit any simple dependence of the local time distribution of the peak ring current (within the lower energy range) on the local time distribution of the source, as suggested by Lavraud et al. [2008]. In addition, we will show how different specifications of the magnetic field in the simulation domain affect ring current dynamics in reference to the 20 November 2007 storm, which include initial results on coupling the CRCM with a three-dimensional (3-D) plasma force balance code to achieve self-consistency in the magnetic field.

Analysis of Disaster Preparedness Planning Measures in DoD Computer Facilities

DTIC Science & Technology

1993-09-01

city, stae, aod ZP code) 10 Source of Funding Numbers SProgram Element No lProject No ITask No lWork Unit Accesion I 11 Title include security...Computer Disaster Recovery .... 13 a. PC and LAN Lessons Learned . . ..... 13 2. Distributed Architectures . . . .. . 14 3. Backups...amount of expense, but no client problems." (Leeke, 1993, p. 8) 2. Distributed Architectures The majority of operations that were disrupted by the

Navy Seals Gone Wild: Publicity, Fame, and the Loss of the Quiet Professional

DTIC Science & Technology

2015-12-01

sources include books, media broadcasts, social media accounts (e.g., Twitter feeds, Facebook), newspapers, government reports, blogs, and academic...identity also puts families and communities at unnecessary risk, especially in the era of social media when so many people are connected. Now-deceased...for public release; distribution is unlimited 12b. DISTRIBUTION CODE A 13. ABSTRACT (maximum 200 words ) Over the past decade, Naval Special

Design and Implementation of a Distributed Version of the NASA Engine Performance Program

NASA Technical Reports Server (NTRS)

Cours, Jeffrey T.

1994-01-01

Distributed NEPP is a new version of the NASA Engine Performance Program that runs in parallel on a collection of Unix workstations connected through a network. The program is fault-tolerant, efficient, and shows significant speed-up in a multi-user, heterogeneous environment. This report describes the issues involved in designing distributed NEPP, the algorithms the program uses, and the performance distributed NEPP achieves. It develops an analytical model to predict and measure the performance of the simple distribution, multiple distribution, and fault-tolerant distribution algorithms that distributed NEPP incorporates. Finally, the appendices explain how to use distributed NEPP and document the organization of the program's source code.

Optical Surface Analysis

DTIC Science & Technology

1996-08-01

34 : " ... , h„.,. ... rP,„onse includinq the time for reviewing instructions, searching existing data sources , gÄÄa^^^ Shsi^ BT ::^^"!in9’°n...DISTRIBUTION CODE ^^ZZ^Z^ZZ centered around the continued development of a unique "^ ^^ to semiconductor materials characterization. A brief...NEW SCATTEROMETER CAPABILITIES 23 4.1 Polarization control 23 4.2 Four-inch sample translation 25 4.3 New photometer 26 4.4 New laser sources 27

Simulation of charge breeding of rubidium using Monte Carlo charge breeding code and generalized ECRIS model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, L.; Cluggish, B.; Kim, J. S.

2010-02-15

A Monte Carlo charge breeding code (MCBC) is being developed by FAR-TECH, Inc. to model the capture and charge breeding of 1+ ion beam in an electron cyclotron resonance ion source (ECRIS) device. The ECRIS plasma is simulated using the generalized ECRIS model which has two choices of boundary settings, free boundary condition and Bohm condition. The charge state distribution of the extracted beam ions is calculated by solving the steady state ion continuity equations where the profiles of the captured ions are used as source terms. MCBC simulations of the charge breeding of Rb+ showed good agreement with recentmore » charge breeding experiments at Argonne National Laboratory (ANL). MCBC correctly predicted the peak of highly charged ion state outputs under free boundary condition and similar charge state distribution width but a lower peak charge state under the Bohm condition. The comparisons between the simulation results and ANL experimental measurements are presented and discussed.« less

Open-source Framework for Storing and Manipulation of Plasma Chemical Reaction Data

NASA Astrophysics Data System (ADS)

Jenkins, T. G.; Averkin, S. N.; Cary, J. R.; Kruger, S. E.

2017-10-01

We present a new open-source framework for storage and manipulation of plasma chemical reaction data that has emerged from our in-house project MUNCHKIN. This framework consists of python scripts and C + + programs. It stores data in an SQL data base for fast retrieval and manipulation. For example, it is possible to fit cross-section data into most widely used analytical expressions, calculate reaction rates for Maxwellian distribution functions of colliding particles, and fit them into different analytical expressions. Another important feature of this framework is the ability to calculate transport properties based on the cross-section data and supplied distribution functions. In addition, this framework allows the export of chemical reaction descriptions in LaTeX format for ease of inclusion in scientific papers. With the help of this framework it is possible to generate corresponding VSim (Particle-In-Cell simulation code) and USim (unstructured multi-fluid code) input blocks with appropriate cross-sections.

NPTFit: A Code Package for Non-Poissonian Template Fitting

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mishra-Sharma, Siddharth; Rodd, Nicholas L.; Safdi, Benjamin R., E-mail: smsharma@princeton.edu, E-mail: nrodd@mit.edu, E-mail: bsafdi@mit.edu

We present NPTFit, an open-source code package, written in Python and Cython, for performing non-Poissonian template fits (NPTFs). The NPTF is a recently developed statistical procedure for characterizing the contribution of unresolved point sources (PSs) to astrophysical data sets. The NPTF was first applied to Fermi gamma-ray data to provide evidence that the excess of ∼GeV gamma-rays observed in the inner regions of the Milky Way likely arises from a population of sub-threshold point sources, and the NPTF has since found additional applications studying sub-threshold extragalactic sources at high Galactic latitudes. The NPTF generalizes traditional astrophysical template fits to allowmore » for the ability to search for populations of unresolved PSs that may follow a given spatial distribution. NPTFit builds upon the framework of the fluctuation analyses developed in X-ray astronomy, thus it likely has applications beyond those demonstrated with gamma-ray data. The NPTFit package utilizes novel computational methods to perform the NPTF efficiently. The code is available at http://github.com/bsafdi/NPTFit and up-to-date and extensive documentation may be found at http://nptfit.readthedocs.io.« less

Ultra-high-energy cosmic rays from low-luminosity active galactic nuclei

NASA Astrophysics Data System (ADS)

Duţan, Ioana; Caramete, Laurenţiu I.

2015-03-01

We investigate the production of ultra-high-energy cosmic ray (UHECR) in relativistic jets from low-luminosity active galactic nuclei (LLAGN). We start by proposing a model for the UHECR contribution from the black holes (BHs) in LLAGN, which present a jet power Pj ⩽1046 erg s-1. This is in contrast to the opinion that only high-luminosity AGN can accelerate particles to energies ⩾ 50 EeV. We rewrite the equations which describe the synchrotron self-absorbed emission of a non-thermal particle distribution to obtain the observed radio flux density from sources with a flat-spectrum core and its relationship to the jet power. We found that the UHECR flux is dependent on the observed radio flux density, the distance to the AGN, and the BH mass, where the particle acceleration regions can be sustained by the magnetic energy extraction from the BH at the center of the AGN. We use a complete sample of 29 radio sources with a total flux density at 5 GHz greater than 0.5 Jy to make predictions for the maximum particle energy, luminosity, and flux of the UHECRs from nearby AGN. These predictions are then used in a semi-analytical code developed in Mathematica (SAM code) as inputs for the Monte-Carlo simulations to obtain the distribution of the arrival direction at the Earth and the energy spectrum of the UHECRs, taking into account their deflection in the intergalactic magnetic fields. For comparison, we also use the CRPropa code with the same initial conditions as for the SAM code. Importantly, to calculate the energy spectrum we also include the weighting of the UHECR flux per each UHECR source. Next, we compare the energy spectrum of the UHECRs with that obtained by the Pierre Auger Observatory.

Design pattern mining using distributed learning automata and DNA sequence alignment.

PubMed

Esmaeilpour, Mansour; Naderifar, Vahideh; Shukur, Zarina

2014-01-01

Over the last decade, design patterns have been used extensively to generate reusable solutions to frequently encountered problems in software engineering and object oriented programming. A design pattern is a repeatable software design solution that provides a template for solving various instances of a general problem. This paper describes a new method for pattern mining, isolating design patterns and relationship between them; and a related tool, DLA-DNA for all implemented pattern and all projects used for evaluation. DLA-DNA achieves acceptable precision and recall instead of other evaluated tools based on distributed learning automata (DLA) and deoxyribonucleic acid (DNA) sequences alignment. The proposed method mines structural design patterns in the object oriented source code and extracts the strong and weak relationships between them, enabling analyzers and programmers to determine the dependency rate of each object, component, and other section of the code for parameter passing and modular programming. The proposed model can detect design patterns better that available other tools those are Pinot, PTIDEJ and DPJF; and the strengths of their relationships. The result demonstrate that whenever the source code is build standard and non-standard, based on the design patterns, then the result of the proposed method is near to DPJF and better that Pinot and PTIDEJ. The proposed model is tested on the several source codes and is compared with other related models and available tools those the results show the precision and recall of the proposed method, averagely 20% and 9.6% are more than Pinot, 27% and 31% are more than PTIDEJ and 3.3% and 2% are more than DPJF respectively. The primary idea of the proposed method is organized in two following steps: the first step, elemental design patterns are identified, while at the second step, is composed to recognize actual design patterns.

NOTE: A Monte Carlo study of dose rate distribution around the specially asymmetric CSM3-a 137Cs source

NASA Astrophysics Data System (ADS)

Pérez-Calatayud, J.; Lliso, F.; Ballester, F.; Serrano, M. A.; Lluch, J. L.; Limami, Y.; Puchades, V.; Casal, E.

2001-07-01

The CSM3 137Cs type stainless-steel encapsulated source is widely used in manually afterloaded low dose rate brachytherapy. A specially asymmetric source, CSM3-a, has been designed by CIS Bio International (France) substituting the eyelet side seed with an inactive material in the CSM3 source. This modification has been done in order to allow a uniform dose level over the upper vaginal surface when this `linear' source is inserted at the top of the dome vaginal applicators. In this study the Monte Carlo GEANT3 simulation code, incorporating the source geometry in detail, was used to investigate the dosimetric characteristics of this special CSM3-a 137Cs brachytherapy source. The absolute dose rate distribution in water around this source was calculated and is presented in the form of an along-away table. Comparison of Sievert integral type calculations with Monte Carlo results are discussed.

Calculation and benchmarking of an azimuthal pressure vessel neutron fluence distribution using the BOXER code and scraping experiments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holzgrewe, F.; Hegedues, F.; Paratte, J.M.

1995-03-01

The light water reactor BOXER code was used to determine the fast azimuthal neutron fluence distribution at the inner surface of the reactor pressure vessel after the tenth cycle of a pressurized water reactor (PWR). Using a cross-section library in 45 groups, fixed-source calculations in transport theory and x-y geometry were carried out to determine the fast azimuthal neutron flux distribution at the inner surface of the pressure vessel for four different cycles. From these results, the fast azimuthal neutron fluence after the tenth cycle was estimated and compared with the results obtained from scraping test experiments. In these experiments,more » small samples of material were taken from the inner surface of the pressure vessel. The fast neutron fluence was then determined form the measured activity of the samples. Comparing the BOXER and scraping test results have maximal differences of 15%, which is very good, considering the factor of 10{sup 3} neutron attenuation between the reactor core and the pressure vessel. To compare the BOXER results with an independent code, the 21st cycle of the PWR was also calculated with the TWODANT two-dimensional transport code, using the same group structure and cross-section library. Deviations in the fast azimuthal flux distribution were found to be <3%, which verifies the accuracy of the BOXER results.« less

Syndrome-source-coding and its universal generalization. [error correcting codes for data compression

NASA Technical Reports Server (NTRS)

Ancheta, T. C., Jr.

1976-01-01

A method of using error-correcting codes to obtain data compression, called syndrome-source-coding, is described in which the source sequence is treated as an error pattern whose syndrome forms the compressed data. It is shown that syndrome-source-coding can achieve arbitrarily small distortion with the number of compressed digits per source digit arbitrarily close to the entropy of a binary memoryless source. A 'universal' generalization of syndrome-source-coding is formulated which provides robustly effective distortionless coding of source ensembles. Two examples are given, comparing the performance of noiseless universal syndrome-source-coding to (1) run-length coding and (2) Lynch-Davisson-Schalkwijk-Cover universal coding for an ensemble of binary memoryless sources.

Kinetic modeling of x-ray laser-driven solid Al plasmas via particle-in-cell simulation

NASA Astrophysics Data System (ADS)

Royle, R.; Sentoku, Y.; Mancini, R. C.; Paraschiv, I.; Johzaki, T.

2017-06-01

Solid-density plasmas driven by intense x-ray free-electron laser (XFEL) radiation are seeded by sources of nonthermal photoelectrons and Auger electrons that ionize and heat the target via collisions. Simulation codes that are commonly used to model such plasmas, such as collisional-radiative (CR) codes, typically assume a Maxwellian distribution and thus instantaneous thermalization of the source electrons. In this study, we present a detailed description and initial applications of a collisional particle-in-cell code, picls, that has been extended with a self-consistent radiation transport model and Monte Carlo models for photoionization and K L L Auger ionization, enabling the fully kinetic simulation of XFEL-driven plasmas. The code is used to simulate two experiments previously performed at the Linac Coherent Light Source investigating XFEL-driven solid-density Al plasmas. It is shown that picls-simulated pulse transmissions using the Ecker-Kröll continuum-lowering model agree much better with measurements than do simulations using the Stewart-Pyatt model. Good quantitative agreement is also found between the time-dependent picls results and those of analogous simulations by the CR code scfly, which was used in the analysis of the experiments to accurately reproduce the observed K α emissions and pulse transmissions. Finally, it is shown that the effects of the nonthermal electrons are negligible for the conditions of the particular experiments under investigation.

Massively parallel data processing for quantitative total flow imaging with optical coherence microscopy and tomography

NASA Astrophysics Data System (ADS)

Sylwestrzak, Marcin; Szlag, Daniel; Marchand, Paul J.; Kumar, Ashwin S.; Lasser, Theo

2017-08-01

We present an application of massively parallel processing of quantitative flow measurements data acquired using spectral optical coherence microscopy (SOCM). The need for massive signal processing of these particular datasets has been a major hurdle for many applications based on SOCM. In view of this difficulty, we implemented and adapted quantitative total flow estimation algorithms on graphics processing units (GPU) and achieved a 150 fold reduction in processing time when compared to a former CPU implementation. As SOCM constitutes the microscopy counterpart to spectral optical coherence tomography (SOCT), the developed processing procedure can be applied to both imaging modalities. We present the developed DLL library integrated in MATLAB (with an example) and have included the source code for adaptations and future improvements. Catalogue identifier: AFBT_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AFBT_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: GNU GPLv3 No. of lines in distributed program, including test data, etc.: 913552 No. of bytes in distributed program, including test data, etc.: 270876249 Distribution format: tar.gz Programming language: CUDA/C, MATLAB. Computer: Intel x64 CPU, GPU supporting CUDA technology. Operating system: 64-bit Windows 7 Professional. Has the code been vectorized or parallelized?: Yes, CPU code has been vectorized in MATLAB, CUDA code has been parallelized. RAM: Dependent on users parameters, typically between several gigabytes and several tens of gigabytes Classification: 6.5, 18. Nature of problem: Speed up of data processing in optical coherence microscopy Solution method: Utilization of GPU for massively parallel data processing Additional comments: Compiled DLL library with source code and documentation, example of utilization (MATLAB script with raw data) Running time: 1,8 s for one B-scan (150 × faster in comparison to the CPU data processing time)

A Monte Carlo model system for core analysis and epithermal neutron beam design at the Washington State University Radiation Center

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burns, T.D. Jr.

1996-05-01

The Monte Carlo Model System (MCMS) for the Washington State University (WSU) Radiation Center provides a means through which core criticality and power distributions can be calculated, as well as providing a method for neutron and photon transport necessary for BNCT epithermal neutron beam design. The computational code used in this Model System is MCNP4A. The geometric capability of this Monte Carlo code allows the WSU system to be modeled very accurately. A working knowledge of the MCNP4A neutron transport code increases the flexibility of the Model System and is recommended, however, the eigenvalue/power density problems can be run withmore » little direct knowledge of MCNP4A. Neutron and photon particle transport require more experience with the MCNP4A code. The Model System consists of two coupled subsystems; the Core Analysis and Source Plane Generator Model (CASP), and the BeamPort Shell Particle Transport Model (BSPT). The CASP Model incorporates the S({alpha}, {beta}) thermal treatment, and is run as a criticality problem yielding, the system eigenvalue (k{sub eff}), the core power distribution, and an implicit surface source for subsequent particle transport in the BSPT Model. The BSPT Model uses the source plane generated by a CASP run to transport particles through the thermal column beamport. The user can create filter arrangements in the beamport and then calculate characteristics necessary for assessing the BNCT potential of the given filter want. Examples of the characteristics to be calculated are: neutron fluxes, neutron currents, fast neutron KERMAs and gamma KERMAs. The MCMS is a useful tool for the WSU system. Those unfamiliar with the MCNP4A code can use the MCMS transparently for core analysis, while more experienced users will find the particle transport capabilities very powerful for BNCT filter design.« less

Deterministically estimated fission source distributions for Monte Carlo k-eigenvalue problems

DOE PAGES

Biondo, Elliott D.; Davidson, Gregory G.; Pandya, Tara M.; ...

2018-04-30

The standard Monte Carlo (MC) k-eigenvalue algorithm involves iteratively converging the fission source distribution using a series of potentially time-consuming inactive cycles before quantities of interest can be tallied. One strategy for reducing the computational time requirements of these inactive cycles is the Sourcerer method, in which a deterministic eigenvalue calculation is performed to obtain an improved initial guess for the fission source distribution. This method has been implemented in the Exnihilo software suite within SCALE using the SPNSPN or SNSN solvers in Denovo and the Shift MC code. The efficacy of this method is assessed with different Denovo solutionmore » parameters for a series of typical k-eigenvalue problems including small criticality benchmarks, full-core reactors, and a fuel cask. Here it is found that, in most cases, when a large number of histories per cycle are required to obtain a detailed flux distribution, the Sourcerer method can be used to reduce the computational time requirements of the inactive cycles.« less

Deterministically estimated fission source distributions for Monte Carlo k-eigenvalue problems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Biondo, Elliott D.; Davidson, Gregory G.; Pandya, Tara M.

The standard Monte Carlo (MC) k-eigenvalue algorithm involves iteratively converging the fission source distribution using a series of potentially time-consuming inactive cycles before quantities of interest can be tallied. One strategy for reducing the computational time requirements of these inactive cycles is the Sourcerer method, in which a deterministic eigenvalue calculation is performed to obtain an improved initial guess for the fission source distribution. This method has been implemented in the Exnihilo software suite within SCALE using the SPNSPN or SNSN solvers in Denovo and the Shift MC code. The efficacy of this method is assessed with different Denovo solutionmore » parameters for a series of typical k-eigenvalue problems including small criticality benchmarks, full-core reactors, and a fuel cask. Here it is found that, in most cases, when a large number of histories per cycle are required to obtain a detailed flux distribution, the Sourcerer method can be used to reduce the computational time requirements of the inactive cycles.« less

A Web-based open-source database for the distribution of hyperspectral signatures

NASA Astrophysics Data System (ADS)

Ferwerda, J. G.; Jones, S. D.; Du, Pei-Jun

2006-10-01

With the coming of age of field spectroscopy as a non-destructive means to collect information on the physiology of vegetation, there is a need for storage of signatures, and, more importantly, their metadata. Without the proper organisation of metadata, the signatures itself become limited. In order to facilitate re-distribution of data, a database for the storage & distribution of hyperspectral signatures and their metadata was designed. The database was built using open-source software, and can be used by the hyperspectral community to share their data. Data is uploaded through a simple web-based interface. The database recognizes major file-formats by ASD, GER and International Spectronics. The database source code is available for download through the hyperspectral.info web domain, and we happily invite suggestion for additions & modification for the database to be submitted through the online forums on the same website.

A Concept for Run-Time Support of the Chapel Language

NASA Technical Reports Server (NTRS)

James, Mark

2006-01-01

A document presents a concept for run-time implementation of other concepts embodied in the Chapel programming language. (Now undergoing development, Chapel is intended to become a standard language for parallel computing that would surpass older such languages in both computational performance in the efficiency with which pre-existing code can be reused and new code written.) The aforementioned other concepts are those of distributions, domains, allocations, and access, as defined in a separate document called "A Semantic Framework for Domains and Distributions in Chapel" and linked to a language specification defined in another separate document called "Chapel Specification 0.3." The concept presented in the instant report is recognition that a data domain that was invented for Chapel offers a novel approach to distributing and processing data in a massively parallel environment. The concept is offered as a starting point for development of working descriptions of functions and data structures that would be necessary to implement interfaces to a compiler for transforming the aforementioned other concepts from their representations in Chapel source code to their run-time implementations.

Utilities for master source code distribution: MAX and Friends

NASA Technical Reports Server (NTRS)

Felippa, Carlos A.

1988-01-01

MAX is a program for the manipulation of FORTRAN master source code (MSC). This is a technique by which one maintains one and only one master copy of a FORTRAN program under a program developing system, which for MAX is assumed to be VAX/VMS. The master copy is not intended to be directly compiled. Instead it must be pre-processed by MAX to produce compilable instances. These instances may correspond to different code versions (for example, double precision versus single precision), different machines (for example, IBM, CDC, Cray) or different operating systems (i.e., VAX/VMS versus VAX/UNIX). The advantage os using a master source is more pronounced in complex application programs that are developed and maintained over many years and are to be transported and executed on several computer environments. The version lag problem that plagues many such programs is avoided by this approach. MAX is complemented by several auxiliary programs that perform nonessential functions. The ensemble is collectively known as MAX and Friends. All of these programs, including MAX, are executed as foreign VAX/VMS commands and can easily be hidden in customized VMS command procedures.

Initial Integration of Noise Prediction Tools for Acoustic Scattering Effects

NASA Technical Reports Server (NTRS)

Nark, Douglas M.; Burley, Casey L.; Tinetti, Ana; Rawls, John W.

2008-01-01

This effort provides an initial glimpse at NASA capabilities available in predicting the scattering of fan noise from a non-conventional aircraft configuration. The Aircraft NOise Prediction Program, Fast Scattering Code, and the Rotorcraft Noise Model were coupled to provide increased fidelity models of scattering effects on engine fan noise sources. The integration of these codes led to the identification of several keys issues entailed in applying such multi-fidelity approaches. In particular, for prediction at noise certification points, the inclusion of distributed sources leads to complications with the source semi-sphere approach. Computational resource requirements limit the use of the higher fidelity scattering code to predict radiated sound pressure levels for full scale configurations at relevant frequencies. And, the ability to more accurately represent complex shielding surfaces in current lower fidelity models is necessary for general application to scattering predictions. This initial step in determining the potential benefits/costs of these new methods over the existing capabilities illustrates a number of the issues that must be addressed in the development of next generation aircraft system noise prediction tools.

A simple way to model nebulae with distributed ionizing stars

NASA Astrophysics Data System (ADS)

Jamet, L.; Morisset, C.

2008-04-01

Aims: This work is a follow-up of a recent article by Ercolano et al. that shows that, in some cases, the spatial dispersion of the ionizing stars in a given nebula may significantly affect its emission spectrum. The authors found that the dispersion of the ionizing stars is accompanied by a decrease in the ionization parameter, which at least partly explains the variations in the nebular spectrum. However, they did not research how other effects associated to the dispersion of the stars may contribute to those variations. Furthermore, they made use of a unique and simplified set of stellar populations. The scope of the present article is to assess whether the variation in the ionization parameter is the dominant effect in the dependence of the nebular spectrum on the distribution of its ionizing stars. We examined this possibility for various regimes of metallicity and age. We also investigated a way to model the distribution of the ionizing sources so as to bypass expensive calculations. Methods: We wrote a code able to generate random stellar populations and to compute the emission spectra of their associated nebulae through the widespread photoionization code cloudy. This code can process two kinds of spatial distributions of the stars: one where all the stars are concentrated at one point, and one where their separation is such that their Strömgren spheres do not overlap. Results: We found that, in most regimes of stellar population ages and gas metallicities, the dependence of the ionization parameter on the distribution of the stars is the dominant factor in the variation of the main nebular diagnostics with this distribution. We derived a method to mimic those effects with a single calculation that makes use of the common assumptions of a central source and a spherical nebula, in the case of constant density objects. This represents a computation time saving by a factor of at least several dozen in the case of H ii regions ionized by massive clusters.

Development and application of a hybrid transport methodology for active interrogation systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Royston, K.; Walters, W.; Haghighat, A.

A hybrid Monte Carlo and deterministic methodology has been developed for application to active interrogation systems. The methodology consists of four steps: i) neutron flux distribution due to neutron source transport and subcritical multiplication; ii) generation of gamma source distribution from (n, 7) interactions; iii) determination of gamma current at a detector window; iv) detection of gammas by the detector. This paper discusses the theory and results of the first three steps for the case of a cargo container with a sphere of HEU in third-density water cargo. To complete the first step, a response-function formulation has been developed tomore » calculate the subcritical multiplication and neutron flux distribution. Response coefficients are pre-calculated using the MCNP5 Monte Carlo code. The second step uses the calculated neutron flux distribution and Bugle-96 (n, 7) cross sections to find the resulting gamma source distribution. In the third step the gamma source distribution is coupled with a pre-calculated adjoint function to determine the gamma current at a detector window. The AIMS (Active Interrogation for Monitoring Special-Nuclear-Materials) software has been written to output the gamma current for a source-detector assembly scanning across a cargo container using the pre-calculated values and taking significantly less time than a reference MCNP5 calculation. (authors)« less

Distributed chemical computing using ChemStar: an open source java remote method invocation architecture applied to large scale molecular data from PubChem.

PubMed

Karthikeyan, M; Krishnan, S; Pandey, Anil Kumar; Bender, Andreas; Tropsha, Alexander

2008-04-01

We present the application of a Java remote method invocation (RMI) based open source architecture to distributed chemical computing. This architecture was previously employed for distributed data harvesting of chemical information from the Internet via the Google application programming interface (API; ChemXtreme). Due to its open source character and its flexibility, the underlying server/client framework can be quickly adopted to virtually every computational task that can be parallelized. Here, we present the server/client communication framework as well as an application to distributed computing of chemical properties on a large scale (currently the size of PubChem; about 18 million compounds), using both the Marvin toolkit as well as the open source JOELib package. As an application, for this set of compounds, the agreement of log P and TPSA between the packages was compared. Outliers were found to be mostly non-druglike compounds and differences could usually be explained by differences in the underlying algorithms. ChemStar is the first open source distributed chemical computing environment built on Java RMI, which is also easily adaptable to user demands due to its "plug-in architecture". The complete source codes as well as calculated properties along with links to PubChem resources are available on the Internet via a graphical user interface at http://moltable.ncl.res.in/chemstar/.

Simulations of ultra-high energy cosmic rays in the local Universe and the origin of cosmic magnetic fields

NASA Astrophysics Data System (ADS)

Hackstein, S.; Vazza, F.; Brüggen, M.; Sorce, J. G.; Gottlöber, S.

2018-04-01

We simulate the propagation of cosmic rays at ultra-high energies, ≳1018 eV, in models of extragalactic magnetic fields in constrained simulations of the local Universe. We use constrained initial conditions with the cosmological magnetohydrodynamics code ENZO. The resulting models of the distribution of magnetic fields in the local Universe are used in the CRPROPA code to simulate the propagation of ultra-high energy cosmic rays. We investigate the impact of six different magneto-genesis scenarios, both primordial and astrophysical, on the propagation of cosmic rays over cosmological distances. Moreover, we study the influence of different source distributions around the Milky Way. Our study shows that different scenarios of magneto-genesis do not have a large impact on the anisotropy measurements of ultra-high energy cosmic rays. However, at high energies above the Greisen-Zatsepin-Kuzmin (GZK)-limit, there is anisotropy caused by the distribution of nearby sources, independent of the magnetic field model. This provides a chance to identify cosmic ray sources with future full-sky measurements and high number statistics at the highest energies. Finally, we compare our results to the dipole signal measured by the Pierre Auger Observatory. All our source models and magnetic field models could reproduce the observed dipole amplitude with a pure iron injection composition. Our results indicate that the dipole is observed due to clustering of secondary nuclei in direction of nearby sources of heavy nuclei. A light injection composition is disfavoured, since the increase in dipole angular power from 4 to 8 EeV is too slow compared to observation by the Pierre Auger Observatory.

A new free and open source tool for space plasma modeling.

NASA Astrophysics Data System (ADS)

Honkonen, I. J.

2014-12-01

I will present a new distributed memory parallel, free and open source computational model for studying space plasma. The model is written in C++ with emphasis on good software development practices and code readability without sacrificing serial or parallel performance. As such the model could be especially useful for education, for learning both (magneto)hydrodynamics (MHD) and computational model development. By using latest features of the C++ standard (2011) it has been possible to develop a very modular program which improves not only the readability of code but also the testability of the model and decreases the effort required to make changes to various parts of the program. Major parts of the model, functionality not directly related to (M)HD, have been outsourced to other freely available libraries which has reduced the development time of the model significantly. I will present an overview of the code architecture as well as details of different parts of the model and will show examples of using the model including preparing input files and plotting results. A multitude of 1-, 2- and 3-dimensional test cases are included in the software distribution and the results of, for example, Kelvin-Helmholtz, bow shock, blast wave and reconnection tests, will be presented.

Towards Full-Waveform Ambient Noise Inversion

NASA Astrophysics Data System (ADS)

Sager, Korbinian; Ermert, Laura; Afanasiev, Michael; Boehm, Christian; Fichtner, Andreas

2017-04-01

Noise tomography usually works under the assumption that the inter-station ambient noise correlation is equal to a scaled version of the Green function between the two receivers. This assumption, however, is only met under specific conditions, e.g. wavefield diffusivity and equipartitioning, or the isotropic distribution of both mono- and dipolar uncorrelated noise sources. These assumptions are typically not satisfied in the Earth. This inconsistency inhibits the exploitation of the full waveform information contained in noise correlations in order to constrain Earth structure and noise generation. To overcome this limitation, we attempt to develop a method that consistently accounts for the distribution of noise sources, 3D heterogeneous Earth structure and the full seismic wave propagation physics. This is intended to improve the resolution of tomographic images, to refine noise source distribution, and thereby to contribute to a better understanding of both Earth structure and noise generation. First, we develop an inversion strategy based on a 2D finite-difference code using adjoint techniques. To enable a joint inversion for noise sources and Earth structure, we investigate the following aspects: i) the capability of different misfit functionals to image wave speed anomalies and source distribution and ii) possible source-structure trade-offs, especially to what extent unresolvable structure can be mapped into the inverted noise source distribution and vice versa. In anticipation of real-data applications, we present an extension of the open-source waveform modelling and inversion package Salvus (http://salvus.io). It allows us to compute correlation functions in 3D media with heterogeneous noise sources at the surface and the corresponding sensitivity kernels for the distribution of noise sources and Earth structure. By studying the effect of noise sources on correlation functions in 3D, we validate the aforementioned inversion strategy and prepare the workflow necessary for the first application of full waveform ambient noise inversion to a global dataset, for which a model for the distribution of noise sources is already available.

Keeping an eye on the ring: COMS plaque loading optimization for improved dose conformity and homogeneity.

PubMed

Gagne, Nolan L; Cutright, Daniel R; Rivard, Mark J

2012-09-01

To improve tumor dose conformity and homogeneity for COMS plaque brachytherapy by investigating the dosimetric effects of varying component source ring radionuclides and source strengths. The MCNP5 Monte Carlo (MC) radiation transport code was used to simulate plaque heterogeneity-corrected dose distributions for individually-activated source rings of 14, 16 and 18 mm diameter COMS plaques, populated with (103)Pd, (125)I and (131)Cs sources. Ellipsoidal tumors were contoured for each plaque size and MATLAB programming was developed to generate tumor dose distributions for all possible ring weighting and radionuclide permutations for a given plaque size and source strength resolution, assuming a 75 Gy apical prescription dose. These dose distributions were analyzed for conformity and homogeneity and compared to reference dose distributions from uniformly-loaded (125)I plaques. The most conformal and homogeneous dose distributions were reproduced within a reference eye environment to assess organ-at-risk (OAR) doses in the Pinnacle(3) treatment planning system (TPS). The gamma-index analysis method was used to quantitatively compare MC and TPS-generated dose distributions. Concentrating > 97% of the total source strength in a single or pair of central (103)Pd seeds produced the most conformal dose distributions, with tumor basal doses a factor of 2-3 higher and OAR doses a factor of 2-3 lower than those of corresponding uniformly-loaded (125)I plaques. Concentrating 82-86% of the total source strength in peripherally-loaded (131)Cs seeds produced the most homogeneous dose distributions, with tumor basal doses 17-25% lower and OAR doses typically 20% higher than those of corresponding uniformly-loaded (125)I plaques. Gamma-index analysis found > 99% agreement between MC and TPS dose distributions. A method was developed to select intra-plaque ring radionuclide compositions and source strengths to deliver more conformal and homogeneous tumor dose distributions than uniformly-loaded (125)I plaques. This method may support coordinated investigations of an appropriate clinical target for eye plaque brachytherapy.

Application of a Java-based, univel geometry, neutral particle Monte Carlo code to the searchlight problem

DOE Office of Scientific and Technical Information (OSTI.GOV)

Charles A. Wemple; Joshua J. Cogliati

2005-04-01

A univel geometry, neutral particle Monte Carlo transport code, written entirely in the Java programming language, is under development for medical radiotherapy applications. The code uses ENDF-VI based continuous energy cross section data in a flexible XML format. Full neutron-photon coupling, including detailed photon production and photonuclear reactions, is included. Charged particle equilibrium is assumed within the patient model so that detailed transport of electrons produced by photon interactions may be neglected. External beam and internal distributed source descriptions for mixed neutron-photon sources are allowed. Flux and dose tallies are performed on a univel basis. A four-tap, shift-register-sequence random numbermore » generator is used. Initial verification and validation testing of the basic neutron transport routines is underway. The searchlight problem was chosen as a suitable first application because of the simplicity of the physical model. Results show excellent agreement with analytic solutions. Computation times for similar numbers of histories are comparable to other neutron MC codes written in C and FORTRAN.« less

Viewstamped Replication for Highly Available Distributed Systems

DTIC Science & Technology

1988-08-01

IDENTIFICATION NUMBER ORGANIZATION (if amocable ) DARPA/DOD I c. ADDRESS (City, State, and ZIP Code) 10. SOURCE OF FUNDING NUMBERS 1400 Wilson Blvd...several managers at once will slow things down, since there will be more message traffic, but the slowdown will be slight. We can, however, avoid these

Remix and Reuse of Source Code in Software Production

ERIC Educational Resources Information Center

Jones, M. Cameron

2010-01-01

The means of producing information and the infrastructure for disseminating it are constantly changing. The web mobilizes information in electronic formats, making it easier to copy, modify, remix, and redistribute. This has changed how information is produced, distributed, and used. People are not just consuming information; they are actively…

Simulation of cesium injection and distribution in rf-driven ion sources for negative hydrogen ion generation.

PubMed

Gutser, R; Fantz, U; Wünderlich, D

2010-02-01

Cesium seeded sources for surface generated negative hydrogen ions are major components of neutral beam injection systems in future large-scale fusion experiments such as ITER. Stability and delivered current density depend highly on the cesium conditions during plasma-on and plasma-off phases of the ion source. The Monte Carlo code CSFLOW3D was used to study the transport of neutral and ionic cesium in both phases. Homogeneous and intense flows were obtained from two cesium sources in the expansion region of the ion source and from a dispenser array, which is located 10 cm in front of the converter surface.

Brief Report: Databases in the Asia-Pacific Region: The Potential for a Distributed Network Approach.

PubMed

Lai, Edward Chia-Cheng; Man, Kenneth K C; Chaiyakunapruk, Nathorn; Cheng, Ching-Lan; Chien, Hsu-Chih; Chui, Celine S L; Dilokthornsakul, Piyameth; Hardy, N Chantelle; Hsieh, Cheng-Yang; Hsu, Chung Y; Kubota, Kiyoshi; Lin, Tzu-Chieh; Liu, Yanfang; Park, Byung Joo; Pratt, Nicole; Roughead, Elizabeth E; Shin, Ju-Young; Watcharathanakij, Sawaeng; Wen, Jin; Wong, Ian C K; Yang, Yea-Huei Kao; Zhang, Yinghong; Setoguchi, Soko

2015-11-01

This study describes the availability and characteristics of databases in Asian-Pacific countries and assesses the feasibility of a distributed network approach in the region. A web-based survey was conducted among investigators using healthcare databases in the Asia-Pacific countries. Potential survey participants were identified through the Asian Pharmacoepidemiology Network. Investigators from a total of 11 databases participated in the survey. Database sources included four nationwide claims databases from Japan, South Korea, and Taiwan; two nationwide electronic health records from Hong Kong and Singapore; a regional electronic health record from western China; two electronic health records from Thailand; and cancer and stroke registries from Taiwan. We identified 11 databases with capabilities for distributed network approaches. Many country-specific coding systems and terminologies have been already converted to international coding systems. The harmonization of health expenditure data is a major obstacle for future investigations attempting to evaluate issues related to medical costs.

SU-E-T-278: Realization of Dose Verification Tool for IMRT Plan Based On DPM

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cai, Jinfeng; Cao, Ruifen; Dai, Yumei

Purpose: To build a Monte Carlo dose verification tool for IMRT Plan by implementing a irradiation source model into DPM code. Extend the ability of DPM to calculate any incident angles and irregular-inhomogeneous fields. Methods: With the virtual source and the energy spectrum which unfolded from the accelerator measurement data,combined with optimized intensity maps to calculate the dose distribution of the irradiation irregular-inhomogeneous field. The irradiation source model of accelerator was substituted by a grid-based surface source. The contour and the intensity distribution of the surface source were optimized by ARTS (Accurate/Advanced Radiotherapy System) optimization module based on the tumormore » configuration. The weight of the emitter was decided by the grid intensity. The direction of the emitter was decided by the combination of the virtual source and the emitter emitting position. The photon energy spectrum unfolded from the accelerator measurement data was adjusted by compensating the contaminated electron source. For verification, measured data and realistic clinical IMRT plan were compared with DPM dose calculation. Results: The regular field was verified by comparing with the measured data. It was illustrated that the differences were acceptable (<2% inside the field, 2–3mm in the penumbra). The dose calculation of irregular field by DPM simulation was also compared with that of FSPB (Finite Size Pencil Beam) and the passing rate of gamma analysis was 95.1% for peripheral lung cancer. The regular field and the irregular rotational field were all within the range of permitting error. The computing time of regular fields were less than 2h, and the test of peripheral lung cancer was 160min. Through parallel processing, the adapted DPM could complete the calculation of IMRT plan within half an hour. Conclusion: The adapted parallelized DPM code with irradiation source model is faster than classic Monte Carlo codes. Its computational accuracy and speed satisfy the clinical requirement, and it is expectable to be a Monte Carlo dose verification tool for IMRT Plan. Strategic Priority Research Program of the China Academy of Science(XDA03040000); National Natural Science Foundation of China (81101132)« less

Skyshine at neutron energies less than or equal to 400 MeV

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alsmiller, A.G. Jr.; Barish, J.; Childs, R.L.

1980-10-01

The dose equivalent at an air-ground interface as a function of distance from an assumed azimuthally symmetric point source of neutrons can be calculated as a double integral. The integration is over the source strength as a function of energy and polar angle weighted by an importance function that depends on the source variables and on the distance from the source to the filed point. The neutron importance function for a source 15 m above the ground emitting only into the upper hemisphere has been calculated using the two-dimensional discrete ordinates code, DOT, and the first collision source code, GRTUNCL,more » in the adjoint mode. This importance function is presented for neutron energies less than or equal to 400 MeV, for source cosine intervals of 1 to .8, .8 to .6 to .4, .4 to .2 and .2 to 0, and for various distances from the source to the field point. As part of the adjoint calculations a photon importance function is also obtained. This importance function for photon energies less than or equal to 14 MEV and for various source cosine intervals and source-to-field point distances is also presented. These importance functions may be used to obtain skyshine dose equivalent estimates for any known source energy-angle distribution.« less

SU-E-T-102: Determination of Dose Distributions and Water-Equivalence of MAGIC-F Polymer Gel for 60Co and 192Ir Brachytherapy Sources

DOE Office of Scientific and Technical Information (OSTI.GOV)

Quevedo, A; Nicolucci, P

2014-06-01

Purpose: Analyse the water-equivalence of MAGIC-f polymer gel for {sup 60}Co and {sup 192}Ir clinical brachytherapy sources, through dose distributions simulated with PENELOPE Monte Carlo code. Methods: The real geometry of {sup 60} (BEBIG, modelo Co0.A86) and {sup 192}192Ir (Varian, model GammaMed Plus) clinical brachytherapy sources were modelled on PENELOPE Monte Carlo simulation code. The most probable emission lines of photons were used for both sources: 17 emission lines for {sup 192}Ir and 12 lines for {sup 60}. The dose distributions were obtained in a cubic water or gel homogeneous phantom (30 × 30 × 30 cm{sup 3}), with themore » source positioned in the middle of the phantom. In all cases the number of simulation showers remained constant at 10{sup 9} particles. A specific material for gel was constructed in PENELOPE using weight fraction components of MAGIC-f: wH = 0,1062, wC = 0,0751, wN = 0,0139, wO = 0,8021, wS = 2,58×10{sup −6} e wCu = 5,08 × 10{sup −6}. The voxel size in the dose distributions was 0.6 mm. Dose distribution maps on the longitudinal and radial direction through the centre of the source were used to analyse the water-equivalence of MAGIC-f. Results: For the {sup 60} source, the maximum diferences in relative doses obtained in the gel and water were 0,65% and 1,90%, for radial and longitudinal direction, respectively. For {sup 192}Ir, the maximum difereces in relative doses were 0,30% and 1,05%, for radial and longitudinal direction, respectively. The materials equivalence can also be verified through the effective atomic number and density of each material: Zef-MAGIC-f = 7,07 e .MAGIC-f = 1,060 g/cm{sup 3} and Zef-water = 7,22. Conclusion: The results showed that MAGIC-f is water equivalent, consequently being suitable to simulate soft tissue, for Cobalt and Iridium energies. Hence, gel can be used as a dosimeter in clinical applications. Further investigation to its use in a clinical protocol is needed.« less

Syndrome source coding and its universal generalization

NASA Technical Reports Server (NTRS)

Ancheta, T. C., Jr.

1975-01-01

A method of using error-correcting codes to obtain data compression, called syndrome-source-coding, is described in which the source sequence is treated as an error pattern whose syndrome forms the compressed data. It is shown that syndrome-source-coding can achieve arbitrarily small distortion with the number of compressed digits per source digit arbitrarily close to the entropy of a binary memoryless source. A universal generalization of syndrome-source-coding is formulated which provides robustly-effective, distortionless, coding of source ensembles.

TOMO3D: 3-D joint refraction and reflection traveltime tomography parallel code for active-source seismic data—synthetic test

NASA Astrophysics Data System (ADS)

Meléndez, A.; Korenaga, J.; Sallarès, V.; Miniussi, A.; Ranero, C. R.

2015-10-01

We present a new 3-D traveltime tomography code (TOMO3D) for the modelling of active-source seismic data that uses the arrival times of both refracted and reflected seismic phases to derive the velocity distribution and the geometry of reflecting boundaries in the subsurface. This code is based on its popular 2-D version TOMO2D from which it inherited the methods to solve the forward and inverse problems. The traveltime calculations are done using a hybrid ray-tracing technique combining the graph and bending methods. The LSQR algorithm is used to perform the iterative regularized inversion to improve the initial velocity and depth models. In order to cope with an increased computational demand due to the incorporation of the third dimension, the forward problem solver, which takes most of the run time (˜90 per cent in the test presented here), has been parallelized with a combination of multi-processing and message passing interface standards. This parallelization distributes the ray-tracing and traveltime calculations among available computational resources. The code's performance is illustrated with a realistic synthetic example, including a checkerboard anomaly and two reflectors, which simulates the geometry of a subduction zone. The code is designed to invert for a single reflector at a time. A data-driven layer-stripping strategy is proposed for cases involving multiple reflectors, and it is tested for the successive inversion of the two reflectors. Layers are bound by consecutive reflectors, and an initial velocity model for each inversion step incorporates the results from previous steps. This strategy poses simpler inversion problems at each step, allowing the recovery of strong velocity discontinuities that would otherwise be smoothened.

The development of a program analysis environment for Ada: Reverse engineering tools for Ada

NASA Technical Reports Server (NTRS)

Cross, James H., II

1991-01-01

The Graphical Representations of Algorithms, Structures, and Processes for Ada (GRASP/Ada) has successfully created and prototyped a new algorithm level graphical representation for Ada software, the Control Structure Diagram (CSD). The primary impetus for creation of the CSD was to improve the comprehension efficiency of Ada software and thus improve reliability and reduce costs. The emphasis was on the automatic generation of the CSD from Ada source code to support reverse engineering and maintenance. The CSD has the potential to replace traditional prettyprinted Ada source code. In Phase 1 of the GRASP/Ada project, the CSD graphical constructs were created and applied manually to several small Ada programs. A prototype (Version 1) was designed and implemented using FLEX and BISON running under the Virtual Memory System (VMS) on a VAX 11-780. In Phase 2, the prototype was improved and ported to the Sun 4 platform under UNIX. A user interface was designed and partially implemented. The prototype was applied successfully to numerous Ada programs ranging in size from several hundred to several thousand lines of source code. In Phase 3 of the project, the prototype was prepared for limited distribution (GRASP/Ada Version 3.0) to facilitate evaluation. The user interface was extensively reworked. The current prototype provides the capability for the user to generate CSD from Ada source code in a reverse engineering mode with a level of flexibility suitable for practical application.

Gamma-ray spectroscopy: The diffuse galactic glow

NASA Technical Reports Server (NTRS)

Hartmann, Dieter H.

1991-01-01

The goal of this project is the development of a numerical code that provides statistical models of the sky distribution of gamma-ray lines due to the production of radioactive isotopes by ongoing Galactic nucleosynthesis. We are particularly interested in quasi-steady emission from novae, supernovae, and stellar winds, but continuum radiation and transient sources must also be considered. We have made significant progress during the first half period of this project and expect the timely completion of a code that can be applied to Oriented Scintillation Spectrometer Experiment (OSSE) Galactic plane survey data.

Rate-distortion analysis of dead-zone plus uniform threshold scalar quantization and its application--part II: two-pass VBR coding for H.264/AVC.

PubMed

Sun, Jun; Duan, Yizhou; Li, Jiangtao; Liu, Jiaying; Guo, Zongming

2013-01-01

In the first part of this paper, we derive a source model describing the relationship between the rate, distortion, and quantization steps of the dead-zone plus uniform threshold scalar quantizers with nearly uniform reconstruction quantizers for generalized Gaussian distribution. This source model consists of rate-quantization, distortion-quantization (D-Q), and distortion-rate (D-R) models. In this part, we first rigorously confirm the accuracy of the proposed source model by comparing the calculated results with the coding data of JM 16.0. Efficient parameter estimation strategies are then developed to better employ this source model in our two-pass rate control method for H.264 variable bit rate coding. Based on our D-Q and D-R models, the proposed method is of high stability, low complexity and is easy to implement. Extensive experiments demonstrate that the proposed method achieves: 1) average peak signal-to-noise ratio variance of only 0.0658 dB, compared to 1.8758 dB of JM 16.0's method, with an average rate control error of 1.95% and 2) significant improvement in smoothing the video quality compared with the latest two-pass rate control method.

SPAMCART: a code for smoothed particle Monte Carlo radiative transfer

NASA Astrophysics Data System (ADS)

Lomax, O.; Whitworth, A. P.

2016-10-01

We present a code for generating synthetic spectral energy distributions and intensity maps from smoothed particle hydrodynamics simulation snapshots. The code is based on the Lucy Monte Carlo radiative transfer method, I.e. it follows discrete luminosity packets as they propagate through a density field, and then uses their trajectories to compute the radiative equilibrium temperature of the ambient dust. The sources can be extended and/or embedded, and discrete and/or diffuse. The density is not mapped on to a grid, and therefore the calculation is performed at exactly the same resolution as the hydrodynamics. We present two example calculations using this method. First, we demonstrate that the code strictly adheres to Kirchhoff's law of radiation. Secondly, we present synthetic intensity maps and spectra of an embedded protostellar multiple system. The algorithm uses data structures that are already constructed for other purposes in modern particle codes. It is therefore relatively simple to implement.

Towards Full-Waveform Ambient Noise Inversion

NASA Astrophysics Data System (ADS)

Sager, K.; Ermert, L. A.; Boehm, C.; Fichtner, A.

2016-12-01

Noise tomography usually works under the assumption that the inter-station ambient noise correlation is equal to a scaled version of the Green function between the two receivers. This assumption, however, is only met under specific conditions, e.g. wavefield diffusivity and equipartitioning, or the isotropic distribution of both mono- and dipolar uncorrelated noise sources. These assumptions are typically not satisfied in the Earth. This inconsistency inhibits the exploitation of the full waveform information contained in noise correlations in order to constrain Earth structure and noise generation. To overcome this limitation, we attempt to develop a method that consistently accounts for the distribution of noise sources, 3D heterogeneous Earth structure and the full seismic wave propagation physics. This is intended to improve the resolution of tomographic images, to refine noise source location, and thereby to contribute to a better understanding of noise generation. We introduce an operator-based formulation for the computation of correlation functions and apply the continuous adjoint method that allows us to compute first and second derivatives of misfit functionals with respect to source distribution and Earth structure efficiently. Based on these developments we design an inversion scheme using a 2D finite-difference code. To enable a joint inversion for noise sources and Earth structure, we investigate the following aspects: The capability of different misfit functionals to image wave speed anomalies and source distribution. Possible source-structure trade-offs, especially to what extent unresolvable structure can be mapped into the inverted noise source distribution and vice versa. In anticipation of real-data applications, we present an extension of the open-source waveform modelling and inversion package Salvus, which allows us to compute correlation functions in 3D media with heterogeneous noise sources at the surface.

Perceptually controlled doping for audio source separation

NASA Astrophysics Data System (ADS)

Mahé, Gaël; Nadalin, Everton Z.; Suyama, Ricardo; Romano, João MT

2014-12-01

The separation of an underdetermined audio mixture can be performed through sparse component analysis (SCA) that relies however on the strong hypothesis that source signals are sparse in some domain. To overcome this difficulty in the case where the original sources are available before the mixing process, the informed source separation (ISS) embeds in the mixture a watermark, which information can help a further separation. Though powerful, this technique is generally specific to a particular mixing setup and may be compromised by an additional bitrate compression stage. Thus, instead of watermarking, we propose a `doping' method that makes the time-frequency representation of each source more sparse, while preserving its audio quality. This method is based on an iterative decrease of the distance between the distribution of the signal and a target sparse distribution, under a perceptual constraint. We aim to show that the proposed approach is robust to audio coding and that the use of the sparsified signals improves the source separation, in comparison with the original sources. In this work, the analysis is made only in instantaneous mixtures and focused on voice sources.

Unfolding the neutron spectrum of a NE213 scintillator using artificial neural networks.

PubMed

Sharghi Ido, A; Bonyadi, M R; Etaati, G R; Shahriari, M

2009-10-01

Artificial neural networks technology has been applied to unfold the neutron spectra from the pulse height distribution measured with NE213 liquid scintillator. Here, both the single and multi-layer perceptron neural network models have been implemented to unfold the neutron spectrum from an Am-Be neutron source. The activation function and the connectivity of the neurons have been investigated and the results have been analyzed in terms of the network's performance. The simulation results show that the neural network that utilizes the Satlins transfer function has the best performance. In addition, omitting the bias connection of the neurons improve the performance of the network. Also, the SCINFUL code is used for generating the response functions in the training phase of the process. Finally, the results of the neural network simulation have been compared with those of the FORIST unfolding code for both (241)Am-Be and (252)Cf neutron sources. The results of neural network are in good agreement with FORIST code.

Multi-channel photon counting DOT system based on digital lock-in detection technique

NASA Astrophysics Data System (ADS)

Wang, Tingting; Zhao, Huijuan; Wang, Zhichao; Hou, Shaohua; Gao, Feng

2011-02-01

Relying on deeper penetration of light in the tissue, Diffuse Optical Tomography (DOT) achieves organ-level tomography diagnosis, which can provide information on anatomical and physiological features. DOT has been widely used in imaging of breast, neonatal cerebral oxygen status and blood oxygen kinetics observed by its non-invasive, security and other advantages. Continuous wave DOT image reconstruction algorithms need the measurement of the surface distribution of the output photon flow inspired by more than one driving source, which means that source coding is necessary. The most currently used source coding in DOT is time-division multiplexing (TDM) technology, which utilizes the optical switch to switch light into optical fiber of different locations. However, in case of large amounts of the source locations or using the multi-wavelength, the measurement time with TDM and the measurement interval between different locations within the same measurement period will therefore become too long to capture the dynamic changes in real-time. In this paper, a frequency division multiplexing source coding technology is developed, which uses light sources modulated by sine waves with different frequencies incident to the imaging chamber simultaneously. Signal corresponding to an individual source is obtained from the mixed output light using digital phase-locked detection technology at the detection end. A digital lock-in detection circuit for photon counting measurement system is implemented on a FPGA development platform. A dual-channel DOT photon counting experimental system is preliminary established, including the two continuous lasers, photon counting detectors, digital lock-in detection control circuit, and codes to control the hardware and display the results. A series of experimental measurements are taken to validate the feasibility of the system. This method developed in this paper greatly accelerates the DOT system measurement, and can also obtain the multiple measurements in different source-detector locations.

OFFSET - RAY TRACING OPTICAL ANALYSIS OF OFFSET SOLAR COLLECTOR FOR SPACE STATION SOLAR DYNAMIC POWER SYSTEM

NASA Technical Reports Server (NTRS)

Jefferies, K.

1994-01-01

OFFSET is a ray tracing computer code for optical analysis of a solar collector. The code models the flux distributions within the receiver cavity produced by reflections from the solar collector. It was developed to model the offset solar collector of the solar dynamic electric power system being developed for Space Station Freedom. OFFSET has been used to improve the understanding of the collector-receiver interface and to guide the efforts of NASA contractors also researching the optical components of the power system. The collector for Space Station Freedom consists of 19 hexagonal panels each containing 24 triangular, reflective facets. Current research is geared toward optimizing flux distribution inside the receiver via changes in collector design and receiver orientation. OFFSET offers many options for experimenting with the design of the system. The offset parabolic collector model configuration is determined by an input file of facet corner coordinates. The user may choose other configurations by changing this file, but to simulate collectors that have other than 19 groups of 24 triangular facets would require modification of the FORTRAN code. Each of the roughly 500 facets in the assembled collector may be independently aimed to smooth out, or tailor, the flux distribution on the receiver's wall. OFFSET simulates the effects of design changes such as in receiver aperture location, tilt angle, and collector facet contour. Unique features of OFFSET include: 1) equations developed to pseudo-randomly select ray originating sources on the Sun which appear evenly distributed and include solar limb darkening; 2) Cone-optics technique used to add surface specular error to the ray originating sources to determine the apparent ray sources of the reflected sun; 3) choice of facet reflective surface contour -- spherical, ideal parabolic, or toroidal; 4) Gaussian distributions of radial and tangential components of surface slope error added to the surface normals at the ten nodal points on each facet; and 5) color contour plots of receiver incident flux distribution generated by PATRAN processing of FORTRAN computer code output. OFFSET output includes a file of input data for confirmation, a PATRAN results file containing the values necessary to plot the flux distribution at the receiver surface, a PATRAN results file containing the intensity distribution on a 40 x 40 cm area of the receiver aperture plane, a data file containing calculated information on the system configuration, a file including the X-Y coordinates of the target points of each collector facet on the aperture opening, and twelve P/PLOT input data files to allow X-Y plotting of various results data. OFFSET is written in FORTRAN (70%) for the IBM VM operating system. The code contains PATRAN statements (12%) and P/PLOT statements (18%) for generating plots. Once the program has been run on VM (or an equivalent system), the PATRAN and P/PLOT files may be transferred to a DEC VAX (or equivalent system) with access to PATRAN for PATRAN post processing. OFFSET was written in 1988 and last updated in 1989. PATRAN is a registered trademark of PDA Engineering. IBM is a registered trademark of International Business Machines Corporation. DEC VAX is a registered trademark of Digital Equipment Corporation.

77 FR 11039 - Proposed Confidentiality Determinations for the Petroleum and Natural Gas Systems Source Category...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-24

... CO 2 carbon dioxide CO 2 e carbon dioxide equivalent CBI confidential business information CFR Code... RFA Regulatory Flexibility Act T-D transmission--distribution UIC Underground Injection Control UMRA... to or greater than 25,000 metric tons carbon dioxide equivalent (mtCO 2 e). The proposed...

A class of ejecta transport test problems

NASA Astrophysics Data System (ADS)

Oro, David M.; Hammerberg, J. E.; Buttler, William T.; Mariam, Fesseha G.; Morris, Christopher L.; Rousculp, Chris; Stone, Joseph B.

2012-03-01

Hydro code implementations of ejecta dynamics at shocked interfaces presume a source distribution function of particulate masses and velocities, f0(m,u;t). Some properties of this source distribution function have been determined from Taylor- and supported-shockwave experiments. Such experiments measure the mass moment of f0 under vacuum conditions assuming weak particle-particle interactions and, usually, fully inelastic scattering (capture) of ejecta particles from piezoelectric diagnostic probes. Recently, planar ejection of W particles into vacuum, Ar, and Xe gas atmospheres have been carried out to provide benchmark transport data for transport model development and validation. We present those experimental results and compare them with modeled transport of the W-ejecta particles in Ar and Xe.

Proof-of-principle experiment of reference-frame-independent quantum key distribution with phase coding

PubMed Central

Liang, Wen-Ye; Wang, Shuang; Li, Hong-Wei; Yin, Zhen-Qiang; Chen, Wei; Yao, Yao; Huang, Jing-Zheng; Guo, Guang-Can; Han, Zheng-Fu

2014-01-01

We have demonstrated a proof-of-principle experiment of reference-frame-independent phase coding quantum key distribution (RFI-QKD) over an 80-km optical fiber. After considering the finite-key bound, we still achieve a distance of 50 km. In this scenario, the phases of the basis states are related by a slowly time-varying transformation. Furthermore, we developed and realized a new decoy state method for RFI-QKD systems with weak coherent sources to counteract the photon-number-splitting attack. With the help of a reference-frame-independent protocol and a Michelson interferometer with Faraday rotator mirrors, our system is rendered immune to the slow phase changes of the interferometer and the polarization disturbances of the channel, making the procedure very robust. PMID:24402550

Compiling global name-space programs for distributed execution

NASA Technical Reports Server (NTRS)

Koelbel, Charles; Mehrotra, Piyush

1990-01-01

Distributed memory machines do not provide hardware support for a global address space. Thus programmers are forced to partition the data across the memories of the architecture and use explicit message passing to communicate data between processors. The compiler support required to allow programmers to express their algorithms using a global name-space is examined. A general method is presented for analysis of a high level source program and along with its translation to a set of independently executing tasks communicating via messages. If the compiler has enough information, this translation can be carried out at compile-time. Otherwise run-time code is generated to implement the required data movement. The analysis required in both situations is described and the performance of the generated code on the Intel iPSC/2 is presented.

Advanced capabilities for materials modelling with Quantum ESPRESSO

NASA Astrophysics Data System (ADS)

Giannozzi, P.; Andreussi, O.; Brumme, T.; Bunau, O.; Buongiorno Nardelli, M.; Calandra, M.; Car, R.; Cavazzoni, C.; Ceresoli, D.; Cococcioni, M.; Colonna, N.; Carnimeo, I.; Dal Corso, A.; de Gironcoli, S.; Delugas, P.; DiStasio, R. A., Jr.; Ferretti, A.; Floris, A.; Fratesi, G.; Fugallo, G.; Gebauer, R.; Gerstmann, U.; Giustino, F.; Gorni, T.; Jia, J.; Kawamura, M.; Ko, H.-Y.; Kokalj, A.; Küçükbenli, E.; Lazzeri, M.; Marsili, M.; Marzari, N.; Mauri, F.; Nguyen, N. L.; Nguyen, H.-V.; Otero-de-la-Roza, A.; Paulatto, L.; Poncé, S.; Rocca, D.; Sabatini, R.; Santra, B.; Schlipf, M.; Seitsonen, A. P.; Smogunov, A.; Timrov, I.; Thonhauser, T.; Umari, P.; Vast, N.; Wu, X.; Baroni, S.

2017-11-01

Quantum EXPRESSO is an integrated suite of open-source computer codes for quantum simulations of materials using state-of-the-art electronic-structure techniques, based on density-functional theory, density-functional perturbation theory, and many-body perturbation theory, within the plane-wave pseudopotential and projector-augmented-wave approaches. Quantum EXPRESSO owes its popularity to the wide variety of properties and processes it allows to simulate, to its performance on an increasingly broad array of hardware architectures, and to a community of researchers that rely on its capabilities as a core open-source development platform to implement their ideas. In this paper we describe recent extensions and improvements, covering new methodologies and property calculators, improved parallelization, code modularization, and extended interoperability both within the distribution and with external software.

Advanced capabilities for materials modelling with Quantum ESPRESSO.

PubMed

Giannozzi, P; Andreussi, O; Brumme, T; Bunau, O; Buongiorno Nardelli, M; Calandra, M; Car, R; Cavazzoni, C; Ceresoli, D; Cococcioni, M; Colonna, N; Carnimeo, I; Dal Corso, A; de Gironcoli, S; Delugas, P; DiStasio, R A; Ferretti, A; Floris, A; Fratesi, G; Fugallo, G; Gebauer, R; Gerstmann, U; Giustino, F; Gorni, T; Jia, J; Kawamura, M; Ko, H-Y; Kokalj, A; Küçükbenli, E; Lazzeri, M; Marsili, M; Marzari, N; Mauri, F; Nguyen, N L; Nguyen, H-V; Otero-de-la-Roza, A; Paulatto, L; Poncé, S; Rocca, D; Sabatini, R; Santra, B; Schlipf, M; Seitsonen, A P; Smogunov, A; Timrov, I; Thonhauser, T; Umari, P; Vast, N; Wu, X; Baroni, S

2017-10-24

Quantum EXPRESSO is an integrated suite of open-source computer codes for quantum simulations of materials using state-of-the-art electronic-structure techniques, based on density-functional theory, density-functional perturbation theory, and many-body perturbation theory, within the plane-wave pseudopotential and projector-augmented-wave approaches. Quantum EXPRESSO owes its popularity to the wide variety of properties and processes it allows to simulate, to its performance on an increasingly broad array of hardware architectures, and to a community of researchers that rely on its capabilities as a core open-source development platform to implement their ideas. In this paper we describe recent extensions and improvements, covering new methodologies and property calculators, improved parallelization, code modularization, and extended interoperability both within the distribution and with external software.

Advanced capabilities for materials modelling with Quantum ESPRESSO.

PubMed

Andreussi, Oliviero; Brumme, Thomas; Bunau, Oana; Buongiorno Nardelli, Marco; Calandra, Matteo; Car, Roberto; Cavazzoni, Carlo; Ceresoli, Davide; Cococcioni, Matteo; Colonna, Nicola; Carnimeo, Ivan; Dal Corso, Andrea; de Gironcoli, Stefano; Delugas, Pietro; DiStasio, Robert; Ferretti, Andrea; Floris, Andrea; Fratesi, Guido; Fugallo, Giorgia; Gebauer, Ralph; Gerstmann, Uwe; Giustino, Feliciano; Gorni, Tommaso; Jia, Junteng; Kawamura, Mitsuaki; Ko, Hsin-Yu; Kokalj, Anton; Küçükbenli, Emine; Lazzeri, Michele; Marsili, Margherita; Marzari, Nicola; Mauri, Francesco; Nguyen, Ngoc Linh; Nguyen, Huy-Viet; Otero-de-la-Roza, Alberto; Paulatto, Lorenzo; Poncé, Samuel; Giannozzi, Paolo; Rocca, Dario; Sabatini, Riccardo; Santra, Biswajit; Schlipf, Martin; Seitsonen, Ari Paavo; Smogunov, Alexander; Timrov, Iurii; Thonhauser, Timo; Umari, Paolo; Vast, Nathalie; Wu, Xifan; Baroni, Stefano

2017-09-27

Quantum ESPRESSO is an integrated suite of open-source computer codes for quantum simulations of materials using state-of-the art electronic-structure techniques, based on density-functional theory, density-functional perturbation theory, and many-body perturbation theory, within the plane-wave pseudo-potential and projector-augmented-wave approaches. Quantum ESPRESSO owes its popularity to the wide variety of properties and processes it allows to simulate, to its performance on an increasingly broad array of hardware architectures, and to a community of researchers that rely on its capabilities as a core open-source development platform to implement theirs ideas. In this paper we describe recent extensions and improvements, covering new methodologies and property calculators, improved parallelization, code modularization, and extended interoperability both within the distribution and with external software. © 2017 IOP Publishing Ltd.

New (125)I brachytherapy source IsoSeed I25.S17plus: Monte Carlo dosimetry simulation and comparison to sources of similar design.

PubMed

Pantelis, Evaggelos; Papagiannis, Panagiotis; Anagnostopoulos, Giorgos; Baltas, Dimos

2013-12-01

To determine the relative dose rate distribution around the new (125)I brachytherapy source IsoSeed I25.S17plus and report results in a form suitable for clinical use. Results for the new source are also compared to corresponding results for other commercially available (125)I sources of similar design. Monte Carlo simulations were performed using the MCNP5 v.1.6 general purpose code. The model of the new source was prepared from information provided by the manufacturer and verified by imaging a sample of ten non-radioactive sources. Corresponding simulations were also performed for the 6711 (125)I brachytherapy source, using updated geometric information presented recently in the literature. The uncertainty of the dose distribution around the new source, as well as the dosimetric quantities derived from it according to the Task Group 43 formalism, were determined from the standard error of the mean of simulations for a sample of fifty source models. These source models were prepared by randomly selecting values of geometric parameters from uniform distributions defined by manufacturer stated tolerances. Results are presented in the form of the quantities defined in the update of the Task Group 43 report, as well as a relative dose rate table in Cartesian coordinates. The dose rate distribution of the new source is comparable to that of sources of similar design (IsoSeed I25.S17, Oncoseed 6711, SelectSeed 130.002, Advantage IAI-125A, I-Seed AgX100, Thinseed 9011). Noticeable differences were observed only for the IsoSeed I25.S06 and Best 2301 sources.

Powerlaw: a Python package for analysis of heavy-tailed distributions.

PubMed

Alstott, Jeff; Bullmore, Ed; Plenz, Dietmar

2014-01-01

Power laws are theoretically interesting probability distributions that are also frequently used to describe empirical data. In recent years, effective statistical methods for fitting power laws have been developed, but appropriate use of these techniques requires significant programming and statistical insight. In order to greatly decrease the barriers to using good statistical methods for fitting power law distributions, we developed the powerlaw Python package. This software package provides easy commands for basic fitting and statistical analysis of distributions. Notably, it also seeks to support a variety of user needs by being exhaustive in the options available to the user. The source code is publicly available and easily extensible.

Advanced Unstructured Grid Generation for Complex Aerodynamic Applications

NASA Technical Reports Server (NTRS)

Pirzadeh, Shahyar Z.

2008-01-01

A new approach for distribution of grid points on the surface and in the volume has been developed and implemented in the NASA unstructured grid generation code VGRID. In addition to the point and line sources of prior work, the new approach utilizes surface and volume sources for automatic curvature-based grid sizing and convenient point distribution in the volume. A new exponential growth function produces smoother and more efficient grids and provides superior control over distribution of grid points in the field. All types of sources support anisotropic grid stretching which not only improves the grid economy but also provides more accurate solutions for certain aerodynamic applications. The new approach does not require a three-dimensional background grid as in the previous methods. Instead, it makes use of an efficient bounding-box auxiliary medium for storing grid parameters defined by surface sources. The new approach is less memory-intensive and more efficient computationally. The grids generated with the new method either eliminate the need for adaptive grid refinement for certain class of problems or provide high quality initial grids that would enhance the performance of many adaptation methods.

Study of a new design of p-N semiconductor detector array for nuclear medicine imaging by monte carlo simulation codes.

PubMed

Hajizadeh-Safar, M; Ghorbani, M; Khoshkharam, S; Ashrafi, Z

2014-07-01

Gamma camera is an important apparatus in nuclear medicine imaging. Its detection part is consists of a scintillation detector with a heavy collimator. Substitution of semiconductor detectors instead of scintillator in these cameras has been effectively studied. In this study, it is aimed to introduce a new design of P-N semiconductor detector array for nuclear medicine imaging. A P-N semiconductor detector composed of N-SnO2 :F, and P-NiO:Li, has been introduced through simulating with MCNPX monte carlo codes. Its sensitivity with different factors such as thickness, dimension, and direction of emission photons were investigated. It is then used to configure a new design of an array in one-dimension and study its spatial resolution for nuclear medicine imaging. One-dimension array with 39 detectors was simulated to measure a predefined linear distribution of Tc(99_m) activity and its spatial resolution. The activity distribution was calculated from detector responses through mathematical linear optimization using LINPROG code on MATLAB software. Three different configurations of one-dimension detector array, horizontal, vertical one sided, and vertical double-sided were simulated. In all of these configurations, the energy windows of the photopeak were ± 1%. The results show that the detector response increases with an increase of dimension and thickness of the detector with the highest sensitivity for emission photons 15-30° above the surface. Horizontal configuration array of detectors is not suitable for imaging of line activity sources. The measured activity distribution with vertical configuration array, double-side detectors, has no similarity with emission sources and hence is not suitable for imaging purposes. Measured activity distribution using vertical configuration array, single side detectors has a good similarity with sources. Therefore, it could be introduced as a suitable configuration for nuclear medicine imaging. It has been shown that using semiconductor P-N detectors such as P-NiO:Li, N-SnO2 :F for gamma detection could be possibly applicable for design of a one dimension array configuration with suitable spatial resolution of 2.7 mm for nuclear medicine imaging.

TIM, a ray-tracing program for METATOY research and its dissemination

NASA Astrophysics Data System (ADS)

Lambert, Dean; Hamilton, Alasdair C.; Constable, George; Snehanshu, Harsh; Talati, Sharvil; Courtial, Johannes

2012-03-01

TIM (The Interactive METATOY) is a ray-tracing program specifically tailored towards our research in METATOYs, which are optical components that appear to be able to create wave-optically forbidden light-ray fields. For this reason, TIM possesses features not found in other ray-tracing programs. TIM can either be used interactively or by modifying the openly available source code; in both cases, it can easily be run as an applet embedded in a web page. Here we describe the basic structure of TIM's source code and how to extend it, and we give examples of how we have used TIM in our own research. Program summaryProgram title: TIM Catalogue identifier: AEKY_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEKY_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: GNU General Public License No. of lines in distributed program, including test data, etc.: 124 478 No. of bytes in distributed program, including test data, etc.: 4 120 052 Distribution format: tar.gz Programming language: Java Computer: Any computer capable of running the Java Virtual Machine (JVM) 1.6 Operating system: Any; developed under Mac OS X Version 10.6 RAM: Typically 145 MB (interactive version running under Mac OS X Version 10.6) Classification: 14, 18 External routines: JAMA [1] (source code included) Nature of problem: Visualisation of scenes that include scene objects that create wave-optically forbidden light-ray fields. Solution method: Ray tracing. Unusual features: Specifically designed to visualise wave-optically forbidden light-ray fields; can visualise ray trajectories; can visualise geometric optic transformations; can create anaglyphs (for viewing with coloured "3D glasses") and random-dot autostereograms of the scene; integrable into web pages. Running time: Problem-dependent; typically seconds for a simple scene.

Skyshine study for next generation of fusion devices

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gohar, Y.; Yang, S.

1987-02-01

A shielding analysis for next generation of fusion devices (ETR/INTOR) was performed to study the dose equivalent outside the reactor building during operation including the contribution from neutrons and photons scattered back by collisions with air nuclei (skyshine component). Two different three-dimensional geometrical models for a tokamak fusion reactor based on INTOR design parameters were developed for this study. In the first geometrical model, the reactor geometry and the spatial distribution of the deuterium-tritium neutron source were simplified for a parametric survey. The second geometrical model employed an explicit representation of the toroidal geometry of the reactor chamber and themore » spatial distribution of the neutron source. The MCNP general Monte Carlo code for neutron and photon transport was used to perform all the calculations. The energy distribution of the neutron source was used explicitly in the calculations with ENDF/B-V data. The dose equivalent results were analyzed as a function of the concrete roof thickness of the reactor building and the location outside the reactor building.« less

A Tutorial on Interfacing the Object Management Group (OMG) Data Distribution Service (DDS) with LabView

NASA Technical Reports Server (NTRS)

Smith, Kevin

2011-01-01

This tutorial will explain the concepts and steps for interfacing a National Instruments LabView virtual instrument (VI) running on a Windows platform with another computer via the Object Management Group (OMG) Data Distribution Service (DDS) as implemented by the Twin Oaks Computing CoreDX. This paper is for educational purposes only and therefore, the referenced source code will be simplistic and void of all error checking. Implementation will be accomplished using the C programming language.

Forty Years of Research and Development at Griffiss Air Force Base, June 1951-June 1991

DTIC Science & Technology

1991-06-01

joints to transfer a number of power sources from the stationary base to the rotating antenna in order to develop high power, multi -beam, long-range...2757. 1 2a. DISTFIBUIOWAVALABLUY STATEMENT 12. DISTILUION CODE Approved for public release; distribution unlimited. a3 ABSTRACT *-= in This historical...did not lend itself to the use of footnotes and a formal bibliography, so a brief note on the primary sources is in order here. The bulk of the

Parameter Measurement Methods for Interfacing Hydraulic Systems with Microelectronic Instruments and Controllers.

DTIC Science & Technology

1983-11-01

successfully. I- Accession For NTIS -GO iiiONa DTIC TAB t Unannounced - Justificatio Distribution/ I Availability Codes vail and/or DIst Special IA-11...terms of initial signal power. An active sensor must be excited externally. Such a sensor receives its power from an external source and merely modulates...electrons in the material to gain L enough energy to be emitted. The voltage source causes a positive potential to be felt on the collector, thus causing the

SESAME: a software tool for the numerical dosimetric reconstruction of radiological accidents involving external sources and its application to the accident in Chile in December 2005.

PubMed

Huet, C; Lemosquet, A; Clairand, I; Rioual, J B; Franck, D; de Carlan, L; Aubineau-Lanièce, I; Bottollier-Depois, J F

2009-01-01

Estimating the dose distribution in a victim's body is a relevant indicator in assessing biological damage from exposure in the event of a radiological accident caused by an external source. This dose distribution can be assessed by physical dosimetric reconstruction methods. Physical dosimetric reconstruction can be achieved using experimental or numerical techniques. This article presents the laboratory-developed SESAME--Simulation of External Source Accident with MEdical images--tool specific to dosimetric reconstruction of radiological accidents through numerical simulations which combine voxel geometry and the radiation-material interaction MCNP(X) Monte Carlo computer code. The experimental validation of the tool using a photon field and its application to a radiological accident in Chile in December 2005 are also described.

CLIPS 6.0 - C LANGUAGE INTEGRATED PRODUCTION SYSTEM, VERSION 6.0 (UNIX VERSION)

NASA Technical Reports Server (NTRS)

Donnell, B.

1994-01-01

CLIPS, the C Language Integrated Production System, is a complete environment for developing expert systems -- programs which are specifically intended to model human expertise or knowledge. It is designed to allow artificial intelligence research, development, and delivery on conventional computers. CLIPS 6.0 provides a cohesive tool for handling a wide variety of knowledge with support for three different programming paradigms: rule-based, object-oriented, and procedural. Rule-based programming allows knowledge to be represented as heuristics, or "rules-of-thumb" which specify a set of actions to be performed for a given situation. Object-oriented programming allows complex systems to be modeled as modular components (which can be easily reused to model other systems or create new components). The procedural programming capabilities provided by CLIPS 6.0 allow CLIPS to represent knowledge in ways similar to those allowed in languages such as C, Pascal, Ada, and LISP. Using CLIPS 6.0, one can develop expert system software using only rule-based programming, only object-oriented programming, only procedural programming, or combinations of the three. CLIPS provides extensive features to support the rule-based programming paradigm including seven conflict resolution strategies, dynamic rule priorities, and truth maintenance. CLIPS 6.0 supports more complex nesting of conditional elements in the if portion of a rule ("and", "or", and "not" conditional elements can be placed within a "not" conditional element). In addition, there is no longer a limitation on the number of multifield slots that a deftemplate can contain. The CLIPS Object-Oriented Language (COOL) provides object-oriented programming capabilities. Features supported by COOL include classes with multiple inheritance, abstraction, encapsulation, polymorphism, dynamic binding, and message passing with message-handlers. CLIPS 6.0 supports tight integration of the rule-based programming features of CLIPS with COOL (that is, a rule can pattern match on objects created using COOL). CLIPS 6.0 provides the capability to define functions, overloaded functions, and global variables interactively. In addition, CLIPS can be embedded within procedural code, called as a subroutine, and integrated with languages such as C, FORTRAN and Ada. CLIPS can be easily extended by a user through the use of several well-defined protocols. CLIPS provides several delivery options for programs including the ability to generate stand alone executables or to load programs from text or binary files. CLIPS 6.0 provides support for the modular development and execution of knowledge bases with the defmodule construct. CLIPS modules allow a set of constructs to be grouped together such that explicit control can be maintained over restricting the access of the constructs by other modules. This type of control is similar to global and local scoping used in languages such as C or Ada. By restricting access to deftemplate and defclass constructs, modules can function as blackboards, permitting only certain facts and instances to be seen by other modules. Modules are also used by rules to provide execution control. The CRSV (Cross-Reference, Style, and Verification) utility included with previous version of CLIPS is no longer supported. The capabilities provided by this tool are now available directly within CLIPS 6.0 to aid in the development, debugging, and verification of large rule bases. COSMIC offers four distribution versions of CLIPS 6.0: UNIX (MSC-22433), VMS (MSC-22434), MACINTOSH (MSC-22429), and IBM PC (MSC-22430). Executable files, source code, utilities, documentation, and examples are included on the program media. All distribution versions include identical source code for the command line version of CLIPS 6.0. This source code should compile on any platform with an ANSI C compiler. Each distribution version of CLIPS 6.0, except that for the Macintosh platform, includes an executable for the command line version. For the UNIX version of CLIPS 6.0, the command line interface has been successfully implemented on a Sun4 running SunOS, a DECstation running DEC RISC ULTRIX, an SGI Indigo Elan running IRIX, a DEC Alpha AXP running OSF/1, and an IBM RS/6000 running AIX. Command line interface executables are included for Sun4 computers running SunOS 4.1.1 or later and for the DEC RISC ULTRIX platform. The makefiles may have to be modified slightly to be used on other UNIX platforms. The UNIX, Macintosh, and IBM PC versions of CLIPS 6.0 each have a platform specific interface. Source code, a makefile, and an executable for the Windows 3.1 interface version of CLIPS 6.0 are provided only on the IBM PC distribution diskettes. Source code, a makefile, and an executable for the Macintosh interface version of CLIPS 6.0 are provided only on the Macintosh distribution diskettes. Likewise, for the UNIX version of CLIPS 6.0, only source code and a makefile for an X-Windows interface are provided. The X-Windows interface requires MIT's X Window System, Version 11, Release 4 (X11R4), the Athena Widget Set, and the Xmu library. The source code for the Athena Widget Set is provided on the distribution medium. The X-Windows interface has been successfully implemented on a Sun4 running SunOS 4.1.2 with the MIT distribution of X11R4 (not OpenWindows), an SGI Indigo Elan running IRIX 4.0.5, and a DEC Alpha AXP running OSF/1 1.2. The VAX version of CLIPS 6.0 comes only with the generic command line interface. ASCII makefiles for the command line version of CLIPS are provided on all the distribution media for UNIX, VMS, and DOS. Four executables are provided with the IBM PC version: a windowed interface executable for Windows 3.1 built using Borland C++ v3.1, an editor for use with the windowed interface, a command line version of CLIPS for Windows 3.1, and a 386 command line executable for DOS built using Zortech C++ v3.1. All four executables are capable of utilizing extended memory and require an 80386 CPU or better. Users needing an 8086/8088 or 80286 executable must recompile the CLIPS source code themselves. Users who wish to recompile the DOS executable using Borland C++ or MicroSoft C must use a DOS extender program to produce an executable capable of using extended memory. The version of CLIPS 6.0 for IBM PC compatibles requires DOS v3.3 or later and/or Windows 3.1 or later. It is distributed on a set of three 1.4Mb 3.5 inch diskettes. A hard disk is required. The Macintosh version is distributed in compressed form on two 3.5 inch 1.4Mb Macintosh format diskettes, and requires System 6.0.5, or higher, and 1Mb RAM. The version for DEC VAX/VMS is available in VAX BACKUP format on a 1600 BPI 9-track magnetic tape (standard distribution medium) or a TK50 tape cartridge. The UNIX version is distributed in UNIX tar format on a .25 inch streaming magnetic tape cartridge (Sun QIC-24). For the UNIX version, alternate distribution media and formats are available upon request. The CLIPS 6.0 documentation includes a User's Guide and a three volume Reference Manual consisting of Basic and Advanced Programming Guides and an Interfaces Guide. An electronic version of the documentation is provided on the distribution medium for each version: in MicroSoft Word format for the Macintosh and PC versions of CLIPS, and in both PostScript format and MicroSoft Word for Macintosh format for the UNIX and DEC VAX versions of CLIPS. CLIPS was developed in 1986 and Version 6.0 was released in 1993.

CLIPS 6.0 - C LANGUAGE INTEGRATED PRODUCTION SYSTEM, VERSION 6.0 (IBM PC VERSION)

NASA Technical Reports Server (NTRS)

Donnell, B.

1994-01-01

CLIPS, the C Language Integrated Production System, is a complete environment for developing expert systems -- programs which are specifically intended to model human expertise or knowledge. It is designed to allow artificial intelligence research, development, and delivery on conventional computers. CLIPS 6.0 provides a cohesive tool for handling a wide variety of knowledge with support for three different programming paradigms: rule-based, object-oriented, and procedural. Rule-based programming allows knowledge to be represented as heuristics, or "rules-of-thumb" which specify a set of actions to be performed for a given situation. Object-oriented programming allows complex systems to be modeled as modular components (which can be easily reused to model other systems or create new components). The procedural programming capabilities provided by CLIPS 6.0 allow CLIPS to represent knowledge in ways similar to those allowed in languages such as C, Pascal, Ada, and LISP. Using CLIPS 6.0, one can develop expert system software using only rule-based programming, only object-oriented programming, only procedural programming, or combinations of the three. CLIPS provides extensive features to support the rule-based programming paradigm including seven conflict resolution strategies, dynamic rule priorities, and truth maintenance. CLIPS 6.0 supports more complex nesting of conditional elements in the if portion of a rule ("and", "or", and "not" conditional elements can be placed within a "not" conditional element). In addition, there is no longer a limitation on the number of multifield slots that a deftemplate can contain. The CLIPS Object-Oriented Language (COOL) provides object-oriented programming capabilities. Features supported by COOL include classes with multiple inheritance, abstraction, encapsulation, polymorphism, dynamic binding, and message passing with message-handlers. CLIPS 6.0 supports tight integration of the rule-based programming features of CLIPS with COOL (that is, a rule can pattern match on objects created using COOL). CLIPS 6.0 provides the capability to define functions, overloaded functions, and global variables interactively. In addition, CLIPS can be embedded within procedural code, called as a subroutine, and integrated with languages such as C, FORTRAN and Ada. CLIPS can be easily extended by a user through the use of several well-defined protocols. CLIPS provides several delivery options for programs including the ability to generate stand alone executables or to load programs from text or binary files. CLIPS 6.0 provides support for the modular development and execution of knowledge bases with the defmodule construct. CLIPS modules allow a set of constructs to be grouped together such that explicit control can be maintained over restricting the access of the constructs by other modules. This type of control is similar to global and local scoping used in languages such as C or Ada. By restricting access to deftemplate and defclass constructs, modules can function as blackboards, permitting only certain facts and instances to be seen by other modules. Modules are also used by rules to provide execution control. The CRSV (Cross-Reference, Style, and Verification) utility included with previous version of CLIPS is no longer supported. The capabilities provided by this tool are now available directly within CLIPS 6.0 to aid in the development, debugging, and verification of large rule bases. COSMIC offers four distribution versions of CLIPS 6.0: UNIX (MSC-22433), VMS (MSC-22434), MACINTOSH (MSC-22429), and IBM PC (MSC-22430). Executable files, source code, utilities, documentation, and examples are included on the program media. All distribution versions include identical source code for the command line version of CLIPS 6.0. This source code should compile on any platform with an ANSI C compiler. Each distribution version of CLIPS 6.0, except that for the Macintosh platform, includes an executable for the command line version. For the UNIX version of CLIPS 6.0, the command line interface has been successfully implemented on a Sun4 running SunOS, a DECstation running DEC RISC ULTRIX, an SGI Indigo Elan running IRIX, a DEC Alpha AXP running OSF/1, and an IBM RS/6000 running AIX. Command line interface executables are included for Sun4 computers running SunOS 4.1.1 or later and for the DEC RISC ULTRIX platform. The makefiles may have to be modified slightly to be used on other UNIX platforms. The UNIX, Macintosh, and IBM PC versions of CLIPS 6.0 each have a platform specific interface. Source code, a makefile, and an executable for the Windows 3.1 interface version of CLIPS 6.0 are provided only on the IBM PC distribution diskettes. Source code, a makefile, and an executable for the Macintosh interface version of CLIPS 6.0 are provided only on the Macintosh distribution diskettes. Likewise, for the UNIX version of CLIPS 6.0, only source code and a makefile for an X-Windows interface are provided. The X-Windows interface requires MIT's X Window System, Version 11, Release 4 (X11R4), the Athena Widget Set, and the Xmu library. The source code for the Athena Widget Set is provided on the distribution medium. The X-Windows interface has been successfully implemented on a Sun4 running SunOS 4.1.2 with the MIT distribution of X11R4 (not OpenWindows), an SGI Indigo Elan running IRIX 4.0.5, and a DEC Alpha AXP running OSF/1 1.2. The VAX version of CLIPS 6.0 comes only with the generic command line interface. ASCII makefiles for the command line version of CLIPS are provided on all the distribution media for UNIX, VMS, and DOS. Four executables are provided with the IBM PC version: a windowed interface executable for Windows 3.1 built using Borland C++ v3.1, an editor for use with the windowed interface, a command line version of CLIPS for Windows 3.1, and a 386 command line executable for DOS built using Zortech C++ v3.1. All four executables are capable of utilizing extended memory and require an 80386 CPU or better. Users needing an 8086/8088 or 80286 executable must recompile the CLIPS source code themselves. Users who wish to recompile the DOS executable using Borland C++ or MicroSoft C must use a DOS extender program to produce an executable capable of using extended memory. The version of CLIPS 6.0 for IBM PC compatibles requires DOS v3.3 or later and/or Windows 3.1 or later. It is distributed on a set of three 1.4Mb 3.5 inch diskettes. A hard disk is required. The Macintosh version is distributed in compressed form on two 3.5 inch 1.4Mb Macintosh format diskettes, and requires System 6.0.5, or higher, and 1Mb RAM. The version for DEC VAX/VMS is available in VAX BACKUP format on a 1600 BPI 9-track magnetic tape (standard distribution medium) or a TK50 tape cartridge. The UNIX version is distributed in UNIX tar format on a .25 inch streaming magnetic tape cartridge (Sun QIC-24). For the UNIX version, alternate distribution media and formats are available upon request. The CLIPS 6.0 documentation includes a User's Guide and a three volume Reference Manual consisting of Basic and Advanced Programming Guides and an Interfaces Guide. An electronic version of the documentation is provided on the distribution medium for each version: in MicroSoft Word format for the Macintosh and PC versions of CLIPS, and in both PostScript format and MicroSoft Word for Macintosh format for the UNIX and DEC VAX versions of CLIPS. CLIPS was developed in 1986 and Version 6.0 was released in 1993.

CLIPS 6.0 - C LANGUAGE INTEGRATED PRODUCTION SYSTEM, VERSION 6.0 (MACINTOSH VERSION)

NASA Technical Reports Server (NTRS)

Riley, G.

1994-01-01

CLIPS, the C Language Integrated Production System, is a complete environment for developing expert systems -- programs which are specifically intended to model human expertise or knowledge. It is designed to allow artificial intelligence research, development, and delivery on conventional computers. CLIPS 6.0 provides a cohesive tool for handling a wide variety of knowledge with support for three different programming paradigms: rule-based, object-oriented, and procedural. Rule-based programming allows knowledge to be represented as heuristics, or "rules-of-thumb" which specify a set of actions to be performed for a given situation. Object-oriented programming allows complex systems to be modeled as modular components (which can be easily reused to model other systems or create new components). The procedural programming capabilities provided by CLIPS 6.0 allow CLIPS to represent knowledge in ways similar to those allowed in languages such as C, Pascal, Ada, and LISP. Using CLIPS 6.0, one can develop expert system software using only rule-based programming, only object-oriented programming, only procedural programming, or combinations of the three. CLIPS provides extensive features to support the rule-based programming paradigm including seven conflict resolution strategies, dynamic rule priorities, and truth maintenance. CLIPS 6.0 supports more complex nesting of conditional elements in the if portion of a rule ("and", "or", and "not" conditional elements can be placed within a "not" conditional element). In addition, there is no longer a limitation on the number of multifield slots that a deftemplate can contain. The CLIPS Object-Oriented Language (COOL) provides object-oriented programming capabilities. Features supported by COOL include classes with multiple inheritance, abstraction, encapsulation, polymorphism, dynamic binding, and message passing with message-handlers. CLIPS 6.0 supports tight integration of the rule-based programming features of CLIPS with COOL (that is, a rule can pattern match on objects created using COOL). CLIPS 6.0 provides the capability to define functions, overloaded functions, and global variables interactively. In addition, CLIPS can be embedded within procedural code, called as a subroutine, and integrated with languages such as C, FORTRAN and Ada. CLIPS can be easily extended by a user through the use of several well-defined protocols. CLIPS provides several delivery options for programs including the ability to generate stand alone executables or to load programs from text or binary files. CLIPS 6.0 provides support for the modular development and execution of knowledge bases with the defmodule construct. CLIPS modules allow a set of constructs to be grouped together such that explicit control can be maintained over restricting the access of the constructs by other modules. This type of control is similar to global and local scoping used in languages such as C or Ada. By restricting access to deftemplate and defclass constructs, modules can function as blackboards, permitting only certain facts and instances to be seen by other modules. Modules are also used by rules to provide execution control. The CRSV (Cross-Reference, Style, and Verification) utility included with previous version of CLIPS is no longer supported. The capabilities provided by this tool are now available directly within CLIPS 6.0 to aid in the development, debugging, and verification of large rule bases. COSMIC offers four distribution versions of CLIPS 6.0: UNIX (MSC-22433), VMS (MSC-22434), MACINTOSH (MSC-22429), and IBM PC (MSC-22430). Executable files, source code, utilities, documentation, and examples are included on the program media. All distribution versions include identical source code for the command line version of CLIPS 6.0. This source code should compile on any platform with an ANSI C compiler. Each distribution version of CLIPS 6.0, except that for the Macintosh platform, includes an executable for the command line version. For the UNIX version of CLIPS 6.0, the command line interface has been successfully implemented on a Sun4 running SunOS, a DECstation running DEC RISC ULTRIX, an SGI Indigo Elan running IRIX, a DEC Alpha AXP running OSF/1, and an IBM RS/6000 running AIX. Command line interface executables are included for Sun4 computers running SunOS 4.1.1 or later and for the DEC RISC ULTRIX platform. The makefiles may have to be modified slightly to be used on other UNIX platforms. The UNIX, Macintosh, and IBM PC versions of CLIPS 6.0 each have a platform specific interface. Source code, a makefile, and an executable for the Windows 3.1 interface version of CLIPS 6.0 are provided only on the IBM PC distribution diskettes. Source code, a makefile, and an executable for the Macintosh interface version of CLIPS 6.0 are provided only on the Macintosh distribution diskettes. Likewise, for the UNIX version of CLIPS 6.0, only source code and a makefile for an X-Windows interface are provided. The X-Windows interface requires MIT's X Window System, Version 11, Release 4 (X11R4), the Athena Widget Set, and the Xmu library. The source code for the Athena Widget Set is provided on the distribution medium. The X-Windows interface has been successfully implemented on a Sun4 running SunOS 4.1.2 with the MIT distribution of X11R4 (not OpenWindows), an SGI Indigo Elan running IRIX 4.0.5, and a DEC Alpha AXP running OSF/1 1.2. The VAX version of CLIPS 6.0 comes only with the generic command line interface. ASCII makefiles for the command line version of CLIPS are provided on all the distribution media for UNIX, VMS, and DOS. Four executables are provided with the IBM PC version: a windowed interface executable for Windows 3.1 built using Borland C++ v3.1, an editor for use with the windowed interface, a command line version of CLIPS for Windows 3.1, and a 386 command line executable for DOS built using Zortech C++ v3.1. All four executables are capable of utilizing extended memory and require an 80386 CPU or better. Users needing an 8086/8088 or 80286 executable must recompile the CLIPS source code themselves. Users who wish to recompile the DOS executable using Borland C++ or MicroSoft C must use a DOS extender program to produce an executable capable of using extended memory. The version of CLIPS 6.0 for IBM PC compatibles requires DOS v3.3 or later and/or Windows 3.1 or later. It is distributed on a set of three 1.4Mb 3.5 inch diskettes. A hard disk is required. The Macintosh version is distributed in compressed form on two 3.5 inch 1.4Mb Macintosh format diskettes, and requires System 6.0.5, or higher, and 1Mb RAM. The version for DEC VAX/VMS is available in VAX BACKUP format on a 1600 BPI 9-track magnetic tape (standard distribution medium) or a TK50 tape cartridge. The UNIX version is distributed in UNIX tar format on a .25 inch streaming magnetic tape cartridge (Sun QIC-24). For the UNIX version, alternate distribution media and formats are available upon request. The CLIPS 6.0 documentation includes a User's Guide and a three volume Reference Manual consisting of Basic and Advanced Programming Guides and an Interfaces Guide. An electronic version of the documentation is provided on the distribution medium for each version: in MicroSoft Word format for the Macintosh and PC versions of CLIPS, and in both PostScript format and MicroSoft Word for Macintosh format for the UNIX and DEC VAX versions of CLIPS. CLIPS was developed in 1986 and Version 6.0 was released in 1993.

CLIPS 6.0 - C LANGUAGE INTEGRATED PRODUCTION SYSTEM, VERSION 6.0 (DEC VAX VMS VERSION)

NASA Technical Reports Server (NTRS)

Donnell, B.

1994-01-01

CLIPS, the C Language Integrated Production System, is a complete environment for developing expert systems -- programs which are specifically intended to model human expertise or knowledge. It is designed to allow artificial intelligence research, development, and delivery on conventional computers. CLIPS 6.0 provides a cohesive tool for handling a wide variety of knowledge with support for three different programming paradigms: rule-based, object-oriented, and procedural. Rule-based programming allows knowledge to be represented as heuristics, or "rules-of-thumb" which specify a set of actions to be performed for a given situation. Object-oriented programming allows complex systems to be modeled as modular components (which can be easily reused to model other systems or create new components). The procedural programming capabilities provided by CLIPS 6.0 allow CLIPS to represent knowledge in ways similar to those allowed in languages such as C, Pascal, Ada, and LISP. Using CLIPS 6.0, one can develop expert system software using only rule-based programming, only object-oriented programming, only procedural programming, or combinations of the three. CLIPS provides extensive features to support the rule-based programming paradigm including seven conflict resolution strategies, dynamic rule priorities, and truth maintenance. CLIPS 6.0 supports more complex nesting of conditional elements in the if portion of a rule ("and", "or", and "not" conditional elements can be placed within a "not" conditional element). In addition, there is no longer a limitation on the number of multifield slots that a deftemplate can contain. The CLIPS Object-Oriented Language (COOL) provides object-oriented programming capabilities. Features supported by COOL include classes with multiple inheritance, abstraction, encapsulation, polymorphism, dynamic binding, and message passing with message-handlers. CLIPS 6.0 supports tight integration of the rule-based programming features of CLIPS with COOL (that is, a rule can pattern match on objects created using COOL). CLIPS 6.0 provides the capability to define functions, overloaded functions, and global variables interactively. In addition, CLIPS can be embedded within procedural code, called as a subroutine, and integrated with languages such as C, FORTRAN and Ada. CLIPS can be easily extended by a user through the use of several well-defined protocols. CLIPS provides several delivery options for programs including the ability to generate stand alone executables or to load programs from text or binary files. CLIPS 6.0 provides support for the modular development and execution of knowledge bases with the defmodule construct. CLIPS modules allow a set of constructs to be grouped together such that explicit control can be maintained over restricting the access of the constructs by other modules. This type of control is similar to global and local scoping used in languages such as C or Ada. By restricting access to deftemplate and defclass constructs, modules can function as blackboards, permitting only certain facts and instances to be seen by other modules. Modules are also used by rules to provide execution control. The CRSV (Cross-Reference, Style, and Verification) utility included with previous version of CLIPS is no longer supported. The capabilities provided by this tool are now available directly within CLIPS 6.0 to aid in the development, debugging, and verification of large rule bases. COSMIC offers four distribution versions of CLIPS 6.0: UNIX (MSC-22433), VMS (MSC-22434), MACINTOSH (MSC-22429), and IBM PC (MSC-22430). Executable files, source code, utilities, documentation, and examples are included on the program media. All distribution versions include identical source code for the command line version of CLIPS 6.0. This source code should compile on any platform with an ANSI C compiler. Each distribution version of CLIPS 6.0, except that for the Macintosh platform, includes an executable for the command line version. For the UNIX version of CLIPS 6.0, the command line interface has been successfully implemented on a Sun4 running SunOS, a DECstation running DEC RISC ULTRIX, an SGI Indigo Elan running IRIX, a DEC Alpha AXP running OSF/1, and an IBM RS/6000 running AIX. Command line interface executables are included for Sun4 computers running SunOS 4.1.1 or later and for the DEC RISC ULTRIX platform. The makefiles may have to be modified slightly to be used on other UNIX platforms. The UNIX, Macintosh, and IBM PC versions of CLIPS 6.0 each have a platform specific interface. Source code, a makefile, and an executable for the Windows 3.1 interface version of CLIPS 6.0 are provided only on the IBM PC distribution diskettes. Source code, a makefile, and an executable for the Macintosh interface version of CLIPS 6.0 are provided only on the Macintosh distribution diskettes. Likewise, for the UNIX version of CLIPS 6.0, only source code and a makefile for an X-Windows interface are provided. The X-Windows interface requires MIT's X Window System, Version 11, Release 4 (X11R4), the Athena Widget Set, and the Xmu library. The source code for the Athena Widget Set is provided on the distribution medium. The X-Windows interface has been successfully implemented on a Sun4 running SunOS 4.1.2 with the MIT distribution of X11R4 (not OpenWindows), an SGI Indigo Elan running IRIX 4.0.5, and a DEC Alpha AXP running OSF/1 1.2. The VAX version of CLIPS 6.0 comes only with the generic command line interface. ASCII makefiles for the command line version of CLIPS are provided on all the distribution media for UNIX, VMS, and DOS. Four executables are provided with the IBM PC version: a windowed interface executable for Windows 3.1 built using Borland C++ v3.1, an editor for use with the windowed interface, a command line version of CLIPS for Windows 3.1, and a 386 command line executable for DOS built using Zortech C++ v3.1. All four executables are capable of utilizing extended memory and require an 80386 CPU or better. Users needing an 8086/8088 or 80286 executable must recompile the CLIPS source code themselves. Users who wish to recompile the DOS executable using Borland C++ or MicroSoft C must use a DOS extender program to produce an executable capable of using extended memory. The version of CLIPS 6.0 for IBM PC compatibles requires DOS v3.3 or later and/or Windows 3.1 or later. It is distributed on a set of three 1.4Mb 3.5 inch diskettes. A hard disk is required. The Macintosh version is distributed in compressed form on two 3.5 inch 1.4Mb Macintosh format diskettes, and requires System 6.0.5, or higher, and 1Mb RAM. The version for DEC VAX/VMS is available in VAX BACKUP format on a 1600 BPI 9-track magnetic tape (standard distribution medium) or a TK50 tape cartridge. The UNIX version is distributed in UNIX tar format on a .25 inch streaming magnetic tape cartridge (Sun QIC-24). For the UNIX version, alternate distribution media and formats are available upon request. The CLIPS 6.0 documentation includes a User's Guide and a three volume Reference Manual consisting of Basic and Advanced Programming Guides and an Interfaces Guide. An electronic version of the documentation is provided on the distribution medium for each version: in MicroSoft Word format for the Macintosh and PC versions of CLIPS, and in both PostScript format and MicroSoft Word for Macintosh format for the UNIX and DEC VAX versions of CLIPS. CLIPS was developed in 1986 and Version 6.0 was released in 1993.

Practices in Code Discoverability: Astrophysics Source Code Library

NASA Astrophysics Data System (ADS)

Allen, A.; Teuben, P.; Nemiroff, R. J.; Shamir, L.

2012-09-01

Here we describe the Astrophysics Source Code Library (ASCL), which takes an active approach to sharing astrophysics source code. ASCL's editor seeks out both new and old peer-reviewed papers that describe methods or experiments that involve the development or use of source code, and adds entries for the found codes to the library. This approach ensures that source codes are added without requiring authors to actively submit them, resulting in a comprehensive listing that covers a significant number of the astrophysics source codes used in peer-reviewed studies. The ASCL now has over 340 codes in it and continues to grow. In 2011, the ASCL has on average added 19 codes per month. An advisory committee has been established to provide input and guide the development and expansion of the new site, and a marketing plan has been developed and is being executed. All ASCL source codes have been used to generate results published in or submitted to a refereed journal and are freely available either via a download site or from an identified source. This paper provides the history and description of the ASCL. It lists the requirements for including codes, examines the advantages of the ASCL, and outlines some of its future plans.

Use of computer code for dose distribution studies in A 60CO industrial irradiator

NASA Astrophysics Data System (ADS)

Piña-Villalpando, G.; Sloan, D. P.

1995-09-01

This paper presents a benchmark comparison between calculated and experimental absorbed dose values tor a typical product, in a 60Co industrial irradiator, located at ININ, México. The irradiator is a two levels, two layers system with overlapping product configuration with activity around 300kCi. Experimental values were obtanied from routine dosimetry, using red acrylic pellets. Typical product was Petri dishes packages, apparent density 0.13 g/cm3; that product was chosen because uniform size, large quantity and low density. Minimum dose was fixed in 15 kGy. Calculated values were obtained from QAD-CGGP code. This code uses a point kernel technique, build-up factors fitting was done by geometrical progression and combinatorial geometry is used for system description. Main modifications for the code were related with source sumilation, using punctual sources instead of pencils and an energy and anisotropic emission spectrums were included. Results were, for maximum dose, calculated value (18.2 kGy) was 8% higher than experimental average value (16.8 kGy); for minimum dose, calculated value (13.8 kGy) was 3% higher than experimental average value (14.3 kGy).

Kalai-Smorodinsky bargaining solution for optimal resource allocation over wireless DS-CDMA visual sensor networks

NASA Astrophysics Data System (ADS)

Pandremmenou, Katerina; Kondi, Lisimachos P.; Parsopoulos, Konstantinos E.

2012-01-01

Surveillance applications usually require high levels of video quality, resulting in high power consumption. The existence of a well-behaved scheme to balance video quality and power consumption is crucial for the system's performance. In the present work, we adopt the game-theoretic approach of Kalai-Smorodinsky Bargaining Solution (KSBS) to deal with the problem of optimal resource allocation in a multi-node wireless visual sensor network (VSN). In our setting, the Direct Sequence Code Division Multiple Access (DS-CDMA) method is used for channel access, while a cross-layer optimization design, which employs a central processing server, accounts for the overall system efficacy through all network layers. The task assigned to the central server is the communication with the nodes and the joint determination of their transmission parameters. The KSBS is applied to non-convex utility spaces, efficiently distributing the source coding rate, channel coding rate and transmission powers among the nodes. In the underlying model, the transmission powers assume continuous values, whereas the source and channel coding rates can take only discrete values. Experimental results are reported and discussed to demonstrate the merits of KSBS over competing policies.

Design Pattern Mining Using Distributed Learning Automata and DNA Sequence Alignment

PubMed Central

Esmaeilpour, Mansour; Naderifar, Vahideh; Shukur, Zarina

2014-01-01

Context Over the last decade, design patterns have been used extensively to generate reusable solutions to frequently encountered problems in software engineering and object oriented programming. A design pattern is a repeatable software design solution that provides a template for solving various instances of a general problem. Objective This paper describes a new method for pattern mining, isolating design patterns and relationship between them; and a related tool, DLA-DNA for all implemented pattern and all projects used for evaluation. DLA-DNA achieves acceptable precision and recall instead of other evaluated tools based on distributed learning automata (DLA) and deoxyribonucleic acid (DNA) sequences alignment. Method The proposed method mines structural design patterns in the object oriented source code and extracts the strong and weak relationships between them, enabling analyzers and programmers to determine the dependency rate of each object, component, and other section of the code for parameter passing and modular programming. The proposed model can detect design patterns better that available other tools those are Pinot, PTIDEJ and DPJF; and the strengths of their relationships. Results The result demonstrate that whenever the source code is build standard and non-standard, based on the design patterns, then the result of the proposed method is near to DPJF and better that Pinot and PTIDEJ. The proposed model is tested on the several source codes and is compared with other related models and available tools those the results show the precision and recall of the proposed method, averagely 20% and 9.6% are more than Pinot, 27% and 31% are more than PTIDEJ and 3.3% and 2% are more than DPJF respectively. Conclusion The primary idea of the proposed method is organized in two following steps: the first step, elemental design patterns are identified, while at the second step, is composed to recognize actual design patterns. PMID:25243670

Analysis and Application of Microgrids

NASA Astrophysics Data System (ADS)

Yue, Lu

New trends of generating electricity locally and utilizing non-conventional or renewable energy sources have attracted increasing interests due to the gradual depletion of conventional fossil fuel energy sources. The new type of power generation is called Distributed Generation (DG) and the energy sources utilized by Distributed Generation are termed Distributed Energy Sources (DERs). With DGs embedded in the distribution networks, they evolve from passive distribution networks to active distribution networks enabling bidirectional power flows in the networks. Further incorporating flexible and intelligent controllers and employing future technologies, active distribution networks will turn to a Microgrid. A Microgrid is a small-scale, low voltage Combined with Heat and Power (CHP) supply network designed to supply electrical and heat loads for a small community. To further implement Microgrids, a sophisticated Microgrid Management System must be integrated. However, due to the fact that a Microgrid has multiple DERs integrated and is likely to be deregulated, the ability to perform real-time OPF and economic dispatch with fast speed advanced communication network is necessary. In this thesis, first, problems such as, power system modelling, power flow solving and power system optimization, are studied. Then, Distributed Generation and Microgrid are studied and reviewed, including a comprehensive review over current distributed generation technologies and Microgrid Management Systems, etc. Finally, a computer-based AC optimization method which minimizes the total transmission loss and generation cost of a Microgrid is proposed and a wireless communication scheme based on synchronized Code Division Multiple Access (sCDMA) is proposed. The algorithm is tested with a 6-bus power system and a 9-bus power system.

orthAgogue: an agile tool for the rapid prediction of orthology relations.

PubMed

Ekseth, Ole Kristian; Kuiper, Martin; Mironov, Vladimir

2014-03-01

The comparison of genes and gene products across species depends on high-quality tools to determine the relationships between gene or protein sequences from various species. Although some excellent applications are available and widely used, their performance leaves room for improvement. We developed orthAgogue: a multithreaded C application for high-speed estimation of homology relations in massive datasets, operated via a flexible and easy command-line interface. The orthAgogue software is distributed under the GNU license. The source code and binaries compiled for Linux are available at https://code.google.com/p/orthagogue/.

Development a computer codes to couple PWR-GALE output and PC-CREAM input

NASA Astrophysics Data System (ADS)

Kuntjoro, S.; Budi Setiawan, M.; Nursinta Adi, W.; Deswandri; Sunaryo, G. R.

2018-02-01

Radionuclide dispersion analysis is part of an important reactor safety analysis. From the analysis it can be obtained the amount of doses received by radiation workers and communities around nuclear reactor. The radionuclide dispersion analysis under normal operating conditions is carried out using the PC-CREAM code, and it requires input data such as source term and population distribution. Input data is derived from the output of another program that is PWR-GALE and written Population Distribution data in certain format. Compiling inputs for PC-CREAM programs manually requires high accuracy, as it involves large amounts of data in certain formats and often errors in compiling inputs manually. To minimize errors in input generation, than it is make coupling program for PWR-GALE and PC-CREAM programs and a program for writing population distribution according to the PC-CREAM input format. This work was conducted to create the coupling programming between PWR-GALE output and PC-CREAM input and programming to written population data in the required formats. Programming is done by using Python programming language which has advantages of multiplatform, object-oriented and interactive. The result of this work is software for coupling data of source term and written population distribution data. So that input to PC-CREAM program can be done easily and avoid formatting errors. Programming sourceterm coupling program PWR-GALE and PC-CREAM is completed, so that the creation of PC-CREAM inputs in souceterm and distribution data can be done easily and according to the desired format.

Dosimetric characterizations of GZP6 60Co high dose rate brachytherapy sources: application of superimposition method

PubMed Central

Bahreyni Toossi, Mohammad Taghi; Ghorbani, Mahdi; Mowlavi, Ali Asghar; Meigooni, Ali Soleimani

2012-01-01

Background Dosimetric characteristics of a high dose rate (HDR) GZP6 Co-60 brachytherapy source have been evaluated following American Association of Physicists in MedicineTask Group 43U1 (AAPM TG-43U1) recommendations for their clinical applications. Materials and methods MCNP-4C and MCNPX Monte Carlo codes were utilized to calculate dose rate constant, two dimensional (2D) dose distribution, radial dose function and 2D anisotropy function of the source. These parameters of this source are compared with the available data for Ralstron 60Co and microSelectron192Ir sources. Besides, a superimposition method was developed to extend the obtained results for the GZP6 source No. 3 to other GZP6 sources. Results The simulated value for dose rate constant for GZP6 source was 1.104±0.03 cGyh-1U-1. The graphical and tabulated radial dose function and 2D anisotropy function of this source are presented here. The results of these investigations show that the dosimetric parameters of GZP6 source are comparable to those for the Ralstron source. While dose rate constant for the two 60Co sources are similar to that for the microSelectron192Ir source, there are differences between radial dose function and anisotropy functions. Radial dose function of the 192Ir source is less steep than both 60Co source models. In addition, the 60Co sources are showing more isotropic dose distribution than the 192Ir source. Conclusions The superimposition method is applicable to produce dose distributions for other source arrangements from the dose distribution of a single source. The calculated dosimetric quantities of this new source can be introduced as input data to the GZP6 treatment planning system (TPS) and to validate the performance of the TPS. PMID:23077455

Validation of the MCNP6 electron-photon transport algorithm: multiple-scattering of 13- and 20-MeV electrons in thin foils

NASA Astrophysics Data System (ADS)

Dixon, David A.; Hughes, H. Grady

2017-09-01

This paper presents a validation test comparing angular distributions from an electron multiple-scattering experiment with those generated using the MCNP6 Monte Carlo code system. In this experiment, a 13- and 20-MeV electron pencil beam is deflected by thin foils with atomic numbers from 4 to 79. To determine the angular distribution, the fluence is measured down range of the scattering foil at various radii orthogonal to the beam line. The characteristic angle (the angle for which the max of the distribution is reduced by 1/e) is then determined from the angular distribution and compared with experiment. Multiple scattering foils tested herein include beryllium, carbon, aluminum, copper, and gold. For the default electron-photon transport settings, the calculated characteristic angle was statistically distinguishable from measurement and generally broader than the measured distributions. The average relative difference ranged from 5.8% to 12.2% over all of the foils, source energies, and physics settings tested. This validation illuminated a deficiency in the computation of the underlying angular distributions that is well understood. As a result, code enhancements were made to stabilize the angular distributions in the presence of very small substeps. However, the enhancement only marginally improved results indicating that additional algorithmic details should be studied.

Maximization Network Throughput Based on Improved Genetic Algorithm and Network Coding for Optical Multicast Networks

NASA Astrophysics Data System (ADS)

Wei, Chengying; Xiong, Cuilian; Liu, Huanlin

2017-12-01

Maximal multicast stream algorithm based on network coding (NC) can improve the network's throughput for wavelength-division multiplexing (WDM) networks, which however is far less than the network's maximal throughput in terms of theory. And the existing multicast stream algorithms do not give the information distribution pattern and routing in the meantime. In the paper, an improved genetic algorithm is brought forward to maximize the optical multicast throughput by NC and to determine the multicast stream distribution by hybrid chromosomes construction for multicast with single source and multiple destinations. The proposed hybrid chromosomes are constructed by the binary chromosomes and integer chromosomes, while the binary chromosomes represent optical multicast routing and the integer chromosomes indicate the multicast stream distribution. A fitness function is designed to guarantee that each destination can receive the maximum number of decoding multicast streams. The simulation results showed that the proposed method is far superior over the typical maximal multicast stream algorithms based on NC in terms of network throughput in WDM networks.

Facilitating Internet-Scale Code Retrieval

ERIC Educational Resources Information Center

Bajracharya, Sushil Krishna

2010-01-01

Internet-Scale code retrieval deals with the representation, storage, and access of relevant source code from a large amount of source code available on the Internet. Internet-Scale code retrieval systems support common emerging practices among software developers related to finding and reusing source code. In this dissertation we focus on some…

Photoplus: auxiliary information for printed images based on distributed source coding

NASA Astrophysics Data System (ADS)

Samadani, Ramin; Mukherjee, Debargha

2008-01-01

A printed photograph is difficult to reuse because the digital information that generated the print may no longer be available. This paper describes a mechanism for approximating the original digital image by combining a scan of the printed photograph with small amounts of digital auxiliary information kept together with the print. The auxiliary information consists of a small amount of digital data to enable accurate registration and color-reproduction, followed by a larger amount of digital data to recover residual errors and lost frequencies by distributed Wyner-Ziv coding techniques. Approximating the original digital image enables many uses, including making good quality reprints from the original print, even when they are faded many years later. In essence, the print itself becomes the currency for archiving and repurposing digital images, without requiring computer infrastructure.

Consideration of the Protection Curtain's Shielding Ability after Identifying the Source of Scattered Radiation in the Angiography.

PubMed

Sato, Naoki; Fujibuchi, Toshioh; Toyoda, Takatoshi; Ishida, Takato; Ohura, Hiroki; Miyajima, Ryuichi; Orita, Shinichi; Sueyoshi, Tomonari

2017-06-15

To decrease radiation exposure to medical staff performing angiography, the dose distribution in the angiography was calculated in room using the particle and heavy ion transport code system (PHITS), which is based on Monte Carlo code, and the source of scattered radiation was confirmed using a tungsten sheet by considering the difference shielding performance among different sheet placements. Scattered radiation generated from a flat panel detector, X-ray tube and bed was calculated using the PHITS. In this experiment, the source of scattered radiation was identified as the phantom or acrylic window attached to the X-ray tube thus, a protection curtain was placed on the bed to shield against scattered radiation at low positions. There was an average difference of 20% between the measured and calculated values. The H*(10) value decreased after placing the sheet on the right side of the phantom. Thus, the curtain could decrease scattered radiation. © Crown copyright 2016.

HYPOELLIPSE; a computer program for determining local earthquake hypocentral parameters, magnitude, and first-motion pattern

USGS Publications Warehouse

Lahr, John C.

1999-01-01

This report provides Fortran source code and program manuals for HYPOELLIPSE, a computer program for determining hypocenters and magnitudes of near regional earthquakes and the ellipsoids that enclose the 68-percent confidence volumes of the computed hypocenters. HYPOELLIPSE was developed to meet the needs of U.S. Geological Survey (USGS) scientists studying crustal and sub-crustal earthquakes recorded by a sparse regional seismograph network. The program was extended to locate hypocenters of volcanic earthquakes recorded by seismographs distributed on and around the volcanic edifice, at elevations above and below the hypocenter. HYPOELLIPSE was used to locate events recorded by the USGS southern Alaska seismograph network from October 1971 to the early 1990s. Both UNIX and PC/DOS versions of the source code of the program are provided along with sample runs.

Seismic Analysis Code (SAC): Development, porting, and maintenance within a legacy code base

NASA Astrophysics Data System (ADS)

Savage, B.; Snoke, J. A.

2017-12-01

The Seismic Analysis Code (SAC) is the result of toil of many developers over almost a 40-year history. Initially a Fortran-based code, it has undergone major transitions in underlying bit size from 16 to 32, in the 1980s, and 32 to 64 in 2009; as well as a change in language from Fortran to C in the late 1990s. Maintenance of SAC, the program and its associated libraries, have tracked changes in hardware and operating systems including the advent of Linux in the early 1990, the emergence and demise of Sun/Solaris, variants of OSX processors (PowerPC and x86), and Windows (Cygwin). Traces of these systems are still visible in source code and associated comments. A major concern while improving and maintaining a routinely used, legacy code is a fear of introducing bugs or inadvertently removing favorite features of long-time users. Prior to 2004, SAC was maintained and distributed by LLNL (Lawrence Livermore National Lab). In that year, the license was transferred from LLNL to IRIS (Incorporated Research Institutions for Seismology), but the license is not open source. However, there have been thousands of downloads a year of the package, either source code or binaries for specific system. Starting in 2004, the co-authors have maintained the SAC package for IRIS. In our updates, we fixed bugs, incorporated newly introduced seismic analysis procedures (such as EVALRESP), added new, accessible features (plotting and parsing), and improved the documentation (now in HTML and PDF formats). Moreover, we have added modern software engineering practices to the development of SAC including use of recent source control systems, high-level tests, and scripted, virtualized environments for rapid testing and building. Finally, a "sac-help" listserv (administered by IRIS) was setup for SAC-related issues and is the primary avenue for users seeking advice and reporting bugs. Attempts are always made to respond to issues and bugs in a timely fashion. For the past thirty-plus years, SAC files contained a fixed-length header. Time and distance-related values are stored in single precision, which has become a problem with the increase in desired precision for data compared to thirty years ago. A future goal is to address this precision problem, but in a backward compatible manner. We would also like to transition SAC to a more open source license.

Radiation Source Mapping with Bayesian Inverse Methods

DOE PAGES

Hykes, Joshua M.; Azmy, Yousry Y.

2017-03-22

In this work, we present a method to map the spectral and spatial distributions of radioactive sources using a limited number of detectors. Locating and identifying radioactive materials is important for border monitoring, in accounting for special nuclear material in processing facilities, and in cleanup operations following a radioactive material spill. Most methods to analyze these types of problems make restrictive assumptions about the distribution of the source. In contrast, the source mapping method presented here allows an arbitrary three-dimensional distribution in space and a gamma peak distribution in energy. To apply the method, the problem is cast as anmore » inverse problem where the system’s geometry and material composition are known and fixed, while the radiation source distribution is sought. A probabilistic Bayesian approach is used to solve the resulting inverse problem since the system of equations is ill-posed. The posterior is maximized with a Newton optimization method. The probabilistic approach also provides estimates of the confidence in the final source map prediction. A set of adjoint, discrete ordinates flux solutions, obtained in this work by the Denovo code, is required to efficiently compute detector responses from a candidate source distribution. These adjoint fluxes form the linear mapping from the state space to the response space. The test of the method’s success is simultaneously locating a set of 137Cs and 60Co gamma sources in a room. This test problem is solved using experimental measurements that we collected for this purpose. Because of the weak sources available for use in the experiment, some of the expected photopeaks were not distinguishable from the Compton continuum. However, by supplanting 14 flawed measurements (out of a total of 69) with synthetic responses computed by MCNP, the proof-of-principle source mapping was successful. The locations of the sources were predicted within 25 cm for two of the sources and 90 cm for the third, in a room with an ~4-x 4-m floor plan. Finally, the predicted source intensities were within a factor of ten of their true value.« less

Report on GMI Special Study #15: Radio Frequency Interference

NASA Technical Reports Server (NTRS)

Draper, David W.

2015-01-01

This report contains the results of GMI special study #15. An analysis is conducted to identify sources of radio frequency interference (RFI) to the Global Precipitation Measurement (GPM) Microwave Imager (GMI). The RFI impacts the 10 GHz and 18 GHz channels at both polarities. The sources of RFI are identified for the following conditions: over the water (including major inland water bodies) in the earth view, and over land in the earth view, and in the cold sky view. A best effort is made to identify RFI sources in coastal regions, with noted degradation of flagging performance due to the highly variable earth scene over coastal regions. A database is developed of such sources, including latitude, longitude, country and city of earth emitters, and position in geosynchronous orbit for space emitters. A description of the recommended approach for identifying the sources and locations of RFI in the GMI channels is given in this paper. An algorithm to flag RFI contaminated pixels which can be incorporated into the GMI Level 1Base/1B algorithms is defined, which includes Matlab code to perform the necessary flagging of RFI. A Matlab version of the code is delivered with this distribution.

Effect of high energy electrons on H⁻ production and destruction in a high current DC negative ion source for cyclotron.

PubMed

Onai, M; Etoh, H; Aoki, Y; Shibata, T; Mattei, S; Fujita, S; Hatayama, A; Lettry, J

2016-02-01

Recently, a filament driven multi-cusp negative ion source has been developed for proton cyclotrons in medical applications. In this study, numerical modeling of the filament arc-discharge source plasma has been done with kinetic modeling of electrons in the ion source plasmas by the multi-cusp arc-discharge code and zero dimensional rate equations for hydrogen molecules and negative ions. In this paper, main focus is placed on the effects of the arc-discharge power on the electron energy distribution function and the resultant H(-) production. The modelling results reasonably explains the dependence of the H(-) extraction current on the arc-discharge power in the experiments.

Joint source-channel coding for motion-compensated DCT-based SNR scalable video.

PubMed

Kondi, Lisimachos P; Ishtiaq, Faisal; Katsaggelos, Aggelos K

2002-01-01

In this paper, we develop an approach toward joint source-channel coding for motion-compensated DCT-based scalable video coding and transmission. A framework for the optimal selection of the source and channel coding rates over all scalable layers is presented such that the overall distortion is minimized. The algorithm utilizes universal rate distortion characteristics which are obtained experimentally and show the sensitivity of the source encoder and decoder to channel errors. The proposed algorithm allocates the available bit rate between scalable layers and, within each layer, between source and channel coding. We present the results of this rate allocation algorithm for video transmission over a wireless channel using the H.263 Version 2 signal-to-noise ratio (SNR) scalable codec for source coding and rate-compatible punctured convolutional (RCPC) codes for channel coding. We discuss the performance of the algorithm with respect to the channel conditions, coding methodologies, layer rates, and number of layers.

Nuclear reactor transient analysis via a quasi-static kinetics Monte Carlo method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jo, YuGwon; Cho, Bumhee; Cho, Nam Zin, E-mail: nzcho@kaist.ac.kr

2015-12-31

The predictor-corrector quasi-static (PCQS) method is applied to the Monte Carlo (MC) calculation for reactor transient analysis. To solve the transient fixed-source problem of the PCQS method, fission source iteration is used and a linear approximation of fission source distributions during a macro-time step is introduced to provide delayed neutron source. The conventional particle-tracking procedure is modified to solve the transient fixed-source problem via MC calculation. The PCQS method with MC calculation is compared with the direct time-dependent method of characteristics (MOC) on a TWIGL two-group problem for verification of the computer code. Then, the results on a continuous-energy problemmore » are presented.« less

User's manual: Subsonic/supersonic advanced panel pilot code

NASA Technical Reports Server (NTRS)

Moran, J.; Tinoco, E. N.; Johnson, F. T.

1978-01-01

Sufficient instructions for running the subsonic/supersonic advanced panel pilot code were developed. This software was developed as a vehicle for numerical experimentation and it should not be construed to represent a finished production program. The pilot code is based on a higher order panel method using linearly varying source and quadratically varying doublet distributions for computing both linearized supersonic and subsonic flow over arbitrary wings and bodies. This user's manual contains complete input and output descriptions. A brief description of the method is given as well as practical instructions for proper configurations modeling. Computed results are also included to demonstrate some of the capabilities of the pilot code. The computer program is written in FORTRAN IV for the SCOPE 3.4.4 operations system of the Ames CDC 7600 computer. The program uses overlay structure and thirteen disk files, and it requires approximately 132000 (Octal) central memory words.

ANT: Software for Generating and Evaluating Degenerate Codons for Natural and Expanded Genetic Codes.

PubMed

Engqvist, Martin K M; Nielsen, Jens

2015-08-21

The Ambiguous Nucleotide Tool (ANT) is a desktop application that generates and evaluates degenerate codons. Degenerate codons are used to represent DNA positions that have multiple possible nucleotide alternatives. This is useful for protein engineering and directed evolution, where primers specified with degenerate codons are used as a basis for generating libraries of protein sequences. ANT is intuitive and can be used in a graphical user interface or by interacting with the code through a defined application programming interface. ANT comes with full support for nonstandard, user-defined, or expanded genetic codes (translation tables), which is important because synthetic biology is being applied to an ever widening range of natural and engineered organisms. The Python source code for ANT is freely distributed so that it may be used without restriction, modified, and incorporated in other software or custom data pipelines.

Exposure calculation code module for reactor core analysis: BURNER

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vondy, D.R.; Cunningham, G.W.

1979-02-01

The code module BURNER for nuclear reactor exposure calculations is presented. The computer requirements are shown, as are the reference data and interface data file requirements, and the programmed equations and procedure of calculation are described. The operating history of a reactor is followed over the period between solutions of the space, energy neutronics problem. The end-of-period nuclide concentrations are determined given the necessary information. A steady state, continuous fueling model is treated in addition to the usual fixed fuel model. The control options provide flexibility to select among an unusually wide variety of programmed procedures. The code also providesmore » user option to make a number of auxiliary calculations and print such information as the local gamma source, cumulative exposure, and a fine scale power density distribution in a selected zone. The code is used locally in a system for computation which contains the VENTURE diffusion theory neutronics code and other modules.« less

Modification of codes NUALGAM and BREMRAD, Volume 1

NASA Technical Reports Server (NTRS)

Steyn, J. J.; Huang, R.; Firstenberg, H.

1971-01-01

The NUGAM2 code predicts forward and backward angular energy differential and integrated distributions for gamma photons and fluorescent radiation emerging from finite laminar transport media. It determines buildup and albedo data for scientific research and engineering purposes; it also predicts the emission characteristics of finite radioisotope sources. The results are shown to be in very good agreement with available published data. The code predicts data for many situations in which no published data is available in the energy range up to 5 MeV. The NUGAM3 code predicts the pulse height response of inorganic (NaI and CsI) scintillation detectors to gamma photons. Because it allows the scintillator to be clad and mounted on a photomultiplier as in the experimental or industrial application, it is a more practical and thus useful code than others previously reported. Results are in excellent agreement with published Monte Carlo and experimental data in the energy range up to 4.5 MeV.

The Astrophysics Source Code Library: An Update

NASA Astrophysics Data System (ADS)

Allen, Alice; Nemiroff, R. J.; Shamir, L.; Teuben, P. J.

2012-01-01

The Astrophysics Source Code Library (ASCL), founded in 1999, takes an active approach to sharing astrophysical source code. ASCL's editor seeks out both new and old peer-reviewed papers that describe methods or experiments that involve the development or use of source code, and adds entries for the found codes to the library. This approach ensures that source codes are added without requiring authors to actively submit them, resulting in a comprehensive listing that covers a significant number of the astrophysics source codes used in peer-reviewed studies. The ASCL moved to a new location in 2010, and has over 300 codes in it and continues to grow. In 2011, the ASCL (http://asterisk.apod.com/viewforum.php?f=35) has on average added 19 new codes per month; we encourage scientists to submit their codes for inclusion. An advisory committee has been established to provide input and guide the development and expansion of its new site, and a marketing plan has been developed and is being executed. All ASCL source codes have been used to generate results published in or submitted to a refereed journal and are freely available either via a download site or from an identified source. This presentation covers the history of the ASCL and examines the current state and benefits of the ASCL, the means of and requirements for including codes, and outlines its future plans.

Authorship Attribution of Source Code

ERIC Educational Resources Information Center

Tennyson, Matthew F.

2013-01-01

Authorship attribution of source code is the task of deciding who wrote a program, given its source code. Applications include software forensics, plagiarism detection, and determining software ownership. A number of methods for the authorship attribution of source code have been presented in the past. A review of those existing methods is…

Prioritized Degree Distribution in Wireless Sensor Networks with a Network Coded Data Collection Method

PubMed Central

Wan, Jan; Xiong, Naixue; Zhang, Wei; Zhang, Qinchao; Wan, Zheng

2012-01-01

The reliability of wireless sensor networks (WSNs) can be greatly affected by failures of sensor nodes due to energy exhaustion or the influence of brutal external environment conditions. Such failures seriously affect the data persistence and collection efficiency. Strategies based on network coding technology for WSNs such as LTCDS can improve the data persistence without mass redundancy. However, due to the bad intermediate performance of LTCDS, a serious ‘cliff effect’ may appear during the decoding period, and source data are hard to recover from sink nodes before sufficient encoded packets are collected. In this paper, the influence of coding degree distribution strategy on the ‘cliff effect’ is observed and the prioritized data storage and dissemination algorithm PLTD-ALPHA is presented to achieve better data persistence and recovering performance. With PLTD-ALPHA, the data in sensor network nodes present a trend that their degree distribution increases along with the degree level predefined, and the persistent data packets can be submitted to the sink node according to its degree in order. Finally, the performance of PLTD-ALPHA is evaluated and experiment results show that PLTD-ALPHA can greatly improve the data collection performance and decoding efficiency, while data persistence is not notably affected. PMID:23235451

The HYPE Open Source Community

NASA Astrophysics Data System (ADS)

Strömbäck, L.; Pers, C.; Isberg, K.; Nyström, K.; Arheimer, B.

2013-12-01

The Hydrological Predictions for the Environment (HYPE) model is a dynamic, semi-distributed, process-based, integrated catchment model. It uses well-known hydrological and nutrient transport concepts and can be applied for both small and large scale assessments of water resources and status. In the model, the landscape is divided into classes according to soil type, vegetation and altitude. The soil representation is stratified and can be divided in up to three layers. Water and substances are routed through the same flow paths and storages (snow, soil, groundwater, streams, rivers, lakes) considering turn-over and transformation on the way towards the sea. HYPE has been successfully used in many hydrological applications at SMHI. For Europe, we currently have three different models; The S-HYPE model for Sweden; The BALT-HYPE model for the Baltic Sea; and the E-HYPE model for the whole Europe. These models simulate hydrological conditions and nutrients for their respective areas and are used for characterization, forecasts, and scenario analyses. Model data can be downloaded from hypeweb.smhi.se. In addition, we provide models for the Arctic region, the Arab (Middle East and Northern Africa) region, India, the Niger River basin, the La Plata Basin. This demonstrates the applicability of the HYPE model for large scale modeling in different regions of the world. An important goal with our work is to make our data and tools available as open data and services. For this aim we created the HYPE Open Source Community (OSC) that makes the source code of HYPE available for anyone interested in further development of HYPE. The HYPE OSC (hype.sourceforge.net) is an open source initiative under the Lesser GNU Public License taken by SMHI to strengthen international collaboration in hydrological modeling and hydrological data production. The hypothesis is that more brains and more testing will result in better models and better code. The code is transparent and can be changed and learnt from. New versions of the main code are delivered frequently. HYPE OSC is open to everyone interested in hydrology, hydrological modeling and code development - e.g. scientists, authorities, and consultancies. By joining the HYPE OSC you get access a state-of-the-art operational hydrological model. The HYPE source code is designed to efficiently handle large scale modeling for forecast, hindcast and climate applications. The code is under constant development to improve the hydrological processes, efficiency and readability. In the beginning of 2013 we released a version with new and better modularization based on hydrological processes. This will make the code easier to understand and further develop for a new user. An important challenge in this process is to produce code that is easy for anyone to understand and work with, but still maintain the properties that make the code efficient enough for large scale applications. Input from the HYPE Open Source Community is an important source for future improvements of the HYPE model. Therefore, by joining the community you become an active part of the development, get access to the latest features and can influence future versions of the model.

37 CFR 202.20 - Deposit of copies and phonorecords for copyright registration.

Code of Federal Regulations, 2013 CFR

2013-07-01

...; HTML; WAV; and MPEG family of formats, including MP3. This list of file formats is non-exhaustive and... distributed and used in such a manner that ownership and control of copies remain with the test sponsor or...” shall mean one of the following: (1) The first and last 25 pages or equivalent units of the source code...

Coal Market Module - NEMS Documentation

EIA Publications

2014-01-01

Documents the objectives and the conceptual and methodological approach used in the development of the National Energy Modeling System's (NEMS) Coal Market Module (CMM) used to develop the Annual Energy Outlook 2014 (AEO2014). This report catalogues and describes the assumptions, methodology, estimation techniques, and source code of CMM's two submodules. These are the Coal Production Submodule (CPS) and the Coal Distribution Submodule (CDS).

Flexible configuration-interaction shell-model many-body solver

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, Calvin W.; Ormand, W. Erich; McElvain, Kenneth S.

BIGSTICK Is a flexible configuration-Interaction open-source shell-model code for the many-fermion problem In a shell model (occupation representation) framework. BIGSTICK can generate energy spectra, static and transition one-body densities, and expectation values of scalar operators. Using the built-in Lanczos algorithm one can compute transition probabflity distributions and decompose wave functions into components defined by group theory.

Toward an automated parallel computing environment for geosciences

NASA Astrophysics Data System (ADS)

Zhang, Huai; Liu, Mian; Shi, Yaolin; Yuen, David A.; Yan, Zhenzhen; Liang, Guoping

2007-08-01

Software for geodynamic modeling has not kept up with the fast growing computing hardware and network resources. In the past decade supercomputing power has become available to most researchers in the form of affordable Beowulf clusters and other parallel computer platforms. However, to take full advantage of such computing power requires developing parallel algorithms and associated software, a task that is often too daunting for geoscience modelers whose main expertise is in geosciences. We introduce here an automated parallel computing environment built on open-source algorithms and libraries. Users interact with this computing environment by specifying the partial differential equations, solvers, and model-specific properties using an English-like modeling language in the input files. The system then automatically generates the finite element codes that can be run on distributed or shared memory parallel machines. This system is dynamic and flexible, allowing users to address different problems in geosciences. It is capable of providing web-based services, enabling users to generate source codes online. This unique feature will facilitate high-performance computing to be integrated with distributed data grids in the emerging cyber-infrastructures for geosciences. In this paper we discuss the principles of this automated modeling environment and provide examples to demonstrate its versatility.

Algorithms and physical parameters involved in the calculation of model stellar atmospheres

NASA Astrophysics Data System (ADS)

Merlo, D. C.

This contribution summarizes the Doctoral Thesis presented at Facultad de Matemática, Astronomía y Física, Universidad Nacional de Córdoba for the degree of PhD in Astronomy. We analyze some algorithms and physical parameters involved in the calculation of model stellar atmospheres, such as atomic partition functions, functional relations connecting gaseous and electronic pressure, molecular formation, temperature distribution, chemical compositions, Gaunt factors, atomic cross-sections and scattering sources, as well as computational codes for calculating models. Special attention is paid to the integration of hydrostatic equation. We compare our results with those obtained by other authors, finding reasonable agreement. We make efforts on the implementation of methods that modify the originally adopted temperature distribution in the atmosphere, in order to obtain constant energy flux throughout. We find limitations and we correct numerical instabilities. We integrate the transfer equation solving directly the integral equation involving the source function. As a by-product, we calculate updated atomic partition functions of the light elements. Also, we discuss and enumerate carefully selected formulae for the monochromatic absorption and dispersion of some atomic and molecular species. Finally, we obtain a flexible code to calculate model stellar atmospheres.

Opendf - An Implementation of the Dual Fermion Method for Strongly Correlated Systems

NASA Astrophysics Data System (ADS)

Antipov, Andrey E.; LeBlanc, James P. F.; Gull, Emanuel

The dual fermion method is a multiscale approach for solving lattice problems of interacting strongly correlated systems. In this paper, we present the opendfcode, an open-source implementation of the dual fermion method applicable to fermionic single- orbital lattice models in dimensions D = 1, 2, 3 and 4. The method is built on a dynamical mean field starting point, which neglects all local correlations, and perturbatively adds spatial correlations. Our code is distributed as an open-source package under the GNU public license version 2.

Towards a Full Waveform Ambient Noise Inversion

NASA Astrophysics Data System (ADS)

Sager, K.; Ermert, L. A.; Boehm, C.; Fichtner, A.

2015-12-01

Noise tomography usually works under the assumption that the inter-station ambient noise correlation is equal to a scaled version of the Green's function between the two receivers. This assumption, however, is only met under specific conditions, for instance, wavefield diffusivity and equipartitioning, zero attenuation, etc., that are typically not satisfied in the Earth. This inconsistency inhibits the exploitation of the full waveform information contained in noise correlations regarding Earth structure and noise generation. To overcome this limitation we attempt to develop a method that consistently accounts for noise distribution, 3D heterogeneous Earth structure and the full seismic wave propagation physics in order to improve the current resolution of tomographic images of the Earth. As an initial step towards a full waveform ambient noise inversion we develop a preliminary inversion scheme based on a 2D finite-difference code simulating correlation functions and on adjoint techniques. With respect to our final goal, a simultaneous inversion for noise distribution and Earth structure, we address the following two aspects: (1) the capabilities of different misfit functionals to image wave speed anomalies and source distribution and (2) possible source-structure trade-offs, especially to what extent unresolvable structure could be mapped into the inverted noise source distribution and vice versa.

Evaluation of neutron skyshine from a cyclotron

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huyashi, K.; Nakamura, T.

1984-06-01

The dose distribution and the spectrum variation of neutrons due to the skyshine effect have been measured with various detectors in the environment surrounding the cyclotron of the Institute for Nuclear Study, University of Tokyo. The source neutrons were produced by stopping a 52-MeV proton beam into a carbon beam stopper and were extracted upward from the opening in the concrete shield surrounding the cyclotron and then leaked into the atmosphere through the cyclotron building. The dose distribution and the spectrum of neutrons near the beam stopper were also measured in order to get information on the skyshine source. Themore » measured skyshine neutron spectra and dose distribution were analyzed with two codes, MMCR2 and SKYSHINE-II, with the result that the calculated results are in good agreement with the experiment. Valuable characteristics of this experiment are the determination of the energy spectrum and dose distribution of source neutron and the measurement of skyshine neutrons from an actual large-scale accelerator building to the exclusion of direct neutrons transported through the air. This experiment must be useful as a kind of benchmark experiment on the skyshine phenomenon.« less

A measurement-based generalized source model for Monte Carlo dose simulations of CT scans

PubMed Central

Ming, Xin; Feng, Yuanming; Liu, Ransheng; Yang, Chengwen; Zhou, Li; Zhai, Hezheng; Deng, Jun

2018-01-01

The goal of this study is to develop a generalized source model (GSM) for accurate Monte Carlo dose simulations of CT scans based solely on the measurement data without a priori knowledge of scanner specifications. The proposed generalized source model consists of an extended circular source located at x-ray target level with its energy spectrum, source distribution and fluence distribution derived from a set of measurement data conveniently available in the clinic. Specifically, the central axis percent depth dose (PDD) curves measured in water and the cone output factors measured in air were used to derive the energy spectrum and the source distribution respectively with a Levenberg-Marquardt algorithm. The in-air film measurement of fan-beam dose profiles at fixed gantry was back-projected to generate the fluence distribution of the source model. A benchmarked Monte Carlo user code was used to simulate the dose distributions in water with the developed source model as beam input. The feasibility and accuracy of the proposed source model was tested on a GE LightSpeed and a Philips Brilliance Big Bore multi-detector CT (MDCT) scanners available in our clinic. In general, the Monte Carlo simulations of the PDDs in water and dose profiles along lateral and longitudinal directions agreed with the measurements within 4%/1mm for both CT scanners. The absolute dose comparison using two CTDI phantoms (16 cm and 32 cm in diameters) indicated a better than 5% agreement between the Monte Carlo-simulated and the ion chamber-measured doses at a variety of locations for the two scanners. Overall, this study demonstrated that a generalized source model can be constructed based only on a set of measurement data and used for accurate Monte Carlo dose simulations of patients’ CT scans, which would facilitate patient-specific CT organ dose estimation and cancer risk management in the diagnostic and therapeutic radiology. PMID:28079526

A measurement-based generalized source model for Monte Carlo dose simulations of CT scans

NASA Astrophysics Data System (ADS)

Ming, Xin; Feng, Yuanming; Liu, Ransheng; Yang, Chengwen; Zhou, Li; Zhai, Hezheng; Deng, Jun

2017-03-01

The goal of this study is to develop a generalized source model for accurate Monte Carlo dose simulations of CT scans based solely on the measurement data without a priori knowledge of scanner specifications. The proposed generalized source model consists of an extended circular source located at x-ray target level with its energy spectrum, source distribution and fluence distribution derived from a set of measurement data conveniently available in the clinic. Specifically, the central axis percent depth dose (PDD) curves measured in water and the cone output factors measured in air were used to derive the energy spectrum and the source distribution respectively with a Levenberg-Marquardt algorithm. The in-air film measurement of fan-beam dose profiles at fixed gantry was back-projected to generate the fluence distribution of the source model. A benchmarked Monte Carlo user code was used to simulate the dose distributions in water with the developed source model as beam input. The feasibility and accuracy of the proposed source model was tested on a GE LightSpeed and a Philips Brilliance Big Bore multi-detector CT (MDCT) scanners available in our clinic. In general, the Monte Carlo simulations of the PDDs in water and dose profiles along lateral and longitudinal directions agreed with the measurements within 4%/1 mm for both CT scanners. The absolute dose comparison using two CTDI phantoms (16 cm and 32 cm in diameters) indicated a better than 5% agreement between the Monte Carlo-simulated and the ion chamber-measured doses at a variety of locations for the two scanners. Overall, this study demonstrated that a generalized source model can be constructed based only on a set of measurement data and used for accurate Monte Carlo dose simulations of patients’ CT scans, which would facilitate patient-specific CT organ dose estimation and cancer risk management in the diagnostic and therapeutic radiology.

Schroedinger’s code: Source code availability and transparency in astrophysics

NASA Astrophysics Data System (ADS)

Ryan, PW; Allen, Alice; Teuben, Peter

2018-01-01

Astronomers use software for their research, but how many of the codes they use are available as source code? We examined a sample of 166 papers from 2015 for clearly identified software use, then searched for source code for the software packages mentioned in these research papers. We categorized the software to indicate whether source code is available for download and whether there are restrictions to accessing it, and if source code was not available, whether some other form of the software, such as a binary, was. Over 40% of the source code for the software used in our sample was not available for download.As URLs have often been used as proxy citations for software, we also extracted URLs from one journal’s 2015 research articles, removed those from certain long-term, reliable domains, and tested the remainder to determine what percentage of these URLs were still accessible in September and October, 2017.

Spallation neutron production and the current intra-nuclear cascade and transport codes

NASA Astrophysics Data System (ADS)

Filges, D.; Goldenbaum, F.; Enke, M.; Galin, J.; Herbach, C.-M.; Hilscher, D.; Jahnke, U.; Letourneau, A.; Lott, B.; Neef, R.-D.; Nünighoff, K.; Paul, N.; Péghaire, A.; Pienkowski, L.; Schaal, H.; Schröder, U.; Sterzenbach, G.; Tietze, A.; Tishchenko, V.; Toke, J.; Wohlmuther, M.

A recent renascent interest in energetic proton-induced production of neutrons originates largely from the inception of projects for target stations of intense spallation neutron sources, like the planned European Spallation Source (ESS), accelerator-driven nuclear reactors, nuclear waste transmutation, and also from the application for radioactive beams. In the framework of such a neutron production, of major importance is the search for ways for the most efficient conversion of the primary beam energy into neutron production. Although the issue has been quite successfully addressed experimentally by varying the incident proton energy for various target materials and by covering a huge collection of different target geometries --providing an exhaustive matrix of benchmark data-- the ultimate challenge is to increase the predictive power of transport codes currently on the market. To scrutinize these codes, calculations of reaction cross-sections, hadronic interaction lengths, average neutron multiplicities, neutron multiplicity and energy distributions, and the development of hadronic showers are confronted with recent experimental data of the NESSI collaboration. Program packages like HERMES, LCS or MCNPX master the prevision of reaction cross-sections, hadronic interaction lengths, averaged neutron multiplicities and neutron multiplicity distributions in thick and thin targets for a wide spectrum of incident proton energies, geometrical shapes and materials of the target generally within less than 10% deviation, while production cross-section measurements for light charged particles on thin targets point out that appreciable distinctions exist within these models.

Update of GRASP/Ada reverse engineering tools for Ada

NASA Technical Reports Server (NTRS)

Cross, James H., II

1992-01-01

The GRASP/Ada project (Graphical Representations of Algorithms, Structures, and Processes for Ada) has successfully created and prototyped a new algorithmic level graphical representation of Ada software, the Control Structure Diagram (CSD). The primary impetus for creation of the CSD was to improve the comprehension efficiency of Ada software and, as a result, improve reliability and reduce costs. The emphasis was on the automatic generation of the CSD from Ada PDL or source code to support reverse engineering and maintenance. The CSD has the potential to replace traditional prettyprinted Ada source code. In Phase 1 of the GRASP/Ada project, the CSD graphical constructs were created and applied manually to several small Ada programs. A prototype (Version 1) was designed and implemented using FLEX and BISON running under VMS on a VAS 11-780. In Phase 2, the prototype was improved and ported to the Sun 4 platform under UNIX. A user interface was designed and partially implemented using the HP widget toolkit and the X Windows System. In Phase 3, the user interface was extensively reworked using the Athena widget toolkit and X Windows. The prototype was applied successfully to numerous Ada programs ranging in size from several hundred to several thousand lines of source code. Following Phase 3, the prototype was evaluated by software engineering students at Auburn University and then updated with significant enhancements to the user interface including editing capabilities. Version 3.2 of the prototype was prepared for limited distribution to facilitate further evaluation. The current prototype provides the capability for the user to generate CSD's from Ada PDL or source code in a reverse engineering as well as forward engineering mode with a level of flexibility suitable for practical application.

Chaste: An Open Source C++ Library for Computational Physiology and Biology

PubMed Central

Mirams, Gary R.; Arthurs, Christopher J.; Bernabeu, Miguel O.; Bordas, Rafel; Cooper, Jonathan; Corrias, Alberto; Davit, Yohan; Dunn, Sara-Jane; Fletcher, Alexander G.; Harvey, Daniel G.; Marsh, Megan E.; Osborne, James M.; Pathmanathan, Pras; Pitt-Francis, Joe; Southern, James; Zemzemi, Nejib; Gavaghan, David J.

2013-01-01

Chaste — Cancer, Heart And Soft Tissue Environment — is an open source C++ library for the computational simulation of mathematical models developed for physiology and biology. Code development has been driven by two initial applications: cardiac electrophysiology and cancer development. A large number of cardiac electrophysiology studies have been enabled and performed, including high-performance computational investigations of defibrillation on realistic human cardiac geometries. New models for the initiation and growth of tumours have been developed. In particular, cell-based simulations have provided novel insight into the role of stem cells in the colorectal crypt. Chaste is constantly evolving and is now being applied to a far wider range of problems. The code provides modules for handling common scientific computing components, such as meshes and solvers for ordinary and partial differential equations (ODEs/PDEs). Re-use of these components avoids the need for researchers to ‘re-invent the wheel’ with each new project, accelerating the rate of progress in new applications. Chaste is developed using industrially-derived techniques, in particular test-driven development, to ensure code quality, re-use and reliability. In this article we provide examples that illustrate the types of problems Chaste can be used to solve, which can be run on a desktop computer. We highlight some scientific studies that have used or are using Chaste, and the insights they have provided. The source code, both for specific releases and the development version, is available to download under an open source Berkeley Software Distribution (BSD) licence at http://www.cs.ox.ac.uk/chaste, together with details of a mailing list and links to documentation and tutorials. PMID:23516352

An Embedded Rule-Based Diagnostic Expert System in Ada

NASA Technical Reports Server (NTRS)

Jones, Robert E.; Liberman, Eugene M.

1992-01-01

Ada is becoming an increasingly popular programming language for large Government-funded software projects. Ada with it portability, transportability, and maintainability lends itself well to today's complex programming environment. In addition, expert systems have also assumed a growing role in providing human-like reasoning capability expertise for computer systems. The integration is discussed of expert system technology with Ada programming language, especially a rule-based expert system using an ART-Ada (Automated Reasoning Tool for Ada) system shell. NASA Lewis was chosen as a beta test site for ART-Ada. The test was conducted by implementing the existing Autonomous Power EXpert System (APEX), a Lisp-based power expert system, in ART-Ada. Three components, the rule-based expert systems, a graphics user interface, and communications software make up SMART-Ada (Systems fault Management with ART-Ada). The rules were written in the ART-Ada development environment and converted to Ada source code. The graphics interface was developed with the Transportable Application Environment (TAE) Plus, which generates Ada source code to control graphics images. SMART-Ada communicates with a remote host to obtain either simulated or real data. The Ada source code generated with ART-Ada, TAE Plus, and communications code was incorporated into an Ada expert system that reads the data from a power distribution test bed, applies the rule to determine a fault, if one exists, and graphically displays it on the screen. The main objective, to conduct a beta test on the ART-Ada rule-based expert system shell, was achieved. The system is operational. New Ada tools will assist in future successful projects. ART-Ada is one such tool and is a viable alternative to the straight Ada code when an application requires a rule-based or knowledge-based approach.

Sustaining Open Source Communities through Hackathons - An Example from the ASPECT Community

NASA Astrophysics Data System (ADS)

Heister, T.; Hwang, L.; Bangerth, W.; Kellogg, L. H.

2016-12-01

The ecosystem surrounding a successful scientific open source software package combines both social and technical aspects. Much thought has been given to the technology side of writing sustainable software for large infrastructure projects and software libraries, but less about building the human capacity to perpetuate scientific software used in computational modeling. One effective format for building capacity is regular multi-day hackathons. Scientific hackathons bring together a group of science domain users and scientific software contributors to make progress on a specific software package. Innovation comes through the chance to work with established and new collaborations. Especially in the domain sciences with small communities, hackathons give geographically distributed scientists an opportunity to connect face-to-face. They foster lively discussions amongst scientists with different expertise, promote new collaborations, and increase transparency in both the technical and scientific aspects of code development. ASPECT is an open source, parallel, extensible finite element code to simulate thermal convection, that began development in 2011 under the Computational Infrastructure for Geodynamics. ASPECT hackathons for the past 3 years have grown the number of authors to >50, training new code maintainers in the process. Hackathons begin with leaders establishing project-specific conventions for development, demonstrating the workflow for code contributions, and reviewing relevant technical skills. Each hackathon expands the developer community. Over 20 scientists add >6,000 lines of code during the >1 week event. Participants grow comfortable contributing to the repository and over half continue to contribute afterwards. A high return rate of participants ensures continuity and stability of the group as well as mentoring for novice members. We hope to build other software communities on this model, but anticipate each to bring their own unique challenges.

Suitability of point kernel dose calculation techniques in brachytherapy treatment planning

PubMed Central

Lakshminarayanan, Thilagam; Subbaiah, K. V.; Thayalan, K.; Kannan, S. E.

2010-01-01

Brachytherapy treatment planning system (TPS) is necessary to estimate the dose to target volume and organ at risk (OAR). TPS is always recommended to account for the effect of tissue, applicator and shielding material heterogeneities exist in applicators. However, most brachytherapy TPS software packages estimate the absorbed dose at a point, taking care of only the contributions of individual sources and the source distribution, neglecting the dose perturbations arising from the applicator design and construction. There are some degrees of uncertainties in dose rate estimations under realistic clinical conditions. In this regard, an attempt is made to explore the suitability of point kernels for brachytherapy dose rate calculations and develop new interactive brachytherapy package, named as BrachyTPS, to suit the clinical conditions. BrachyTPS is an interactive point kernel code package developed to perform independent dose rate calculations by taking into account the effect of these heterogeneities, using two regions build up factors, proposed by Kalos. The primary aim of this study is to validate the developed point kernel code package integrated with treatment planning computational systems against the Monte Carlo (MC) results. In the present work, three brachytherapy applicators commonly used in the treatment of uterine cervical carcinoma, namely (i) Board of Radiation Isotope and Technology (BRIT) low dose rate (LDR) applicator and (ii) Fletcher Green type LDR applicator (iii) Fletcher Williamson high dose rate (HDR) applicator, are studied to test the accuracy of the software. Dose rates computed using the developed code are compared with the relevant results of the MC simulations. Further, attempts are also made to study the dose rate distribution around the commercially available shielded vaginal applicator set (Nucletron). The percentage deviations of BrachyTPS computed dose rate values from the MC results are observed to be within plus/minus 5.5% for BRIT LDR applicator, found to vary from 2.6 to 5.1% for Fletcher green type LDR applicator and are up to −4.7% for Fletcher-Williamson HDR applicator. The isodose distribution plots also show good agreements with the results of previous literatures. The isodose distributions around the shielded vaginal cylinder computed using BrachyTPS code show better agreement (less than two per cent deviation) with MC results in the unshielded region compared to shielded region, where the deviations are observed up to five per cent. The present study implies that the accurate and fast validation of complicated treatment planning calculations is possible with the point kernel code package. PMID:20589118

ALMACAL IV: A catalogue of ALMA calibrator continuum observations

NASA Astrophysics Data System (ADS)

Bonato, M.; Liuzzo, E.; Giannetti, A.; Massardi, M.; De Zotti, G.; Burkutean, S.; Galluzzi, V.; Negrello, M.; Baronchelli, I.; Brand, J.; Zwaan, M. A.; Rygl, K. L. J.; Marchili, N.; Klitsch, A.; Oteo, I.

2018-05-01

We present a catalogue of ALMA flux density measurements of 754 calibrators observed between August 2012 and September 2017, for a total of 16,263 observations in different bands and epochs. The flux densities were measured reprocessing the ALMA images generated in the framework of the ALMACAL project, with a new code developed by the Italian node of the European ALMA Regional Centre. A search in the online databases yielded redshift measurements for 589 sources (˜78 per cent of the total). Almost all sources are flat-spectrum, based on their low-frequency spectral index, and have properties consistent with being blazars of different types. To illustrate the properties of the sample we show the redshift and flux density distributions as well as the distributions of the number of observations of individual sources and of time spans in the source frame for sources observed in bands 3 (84-116 GHz) and 6 (211-275 GHz). As examples of the scientific investigations allowed by the catalogue we briefly discuss the variability properties of our sources in ALMA bands 3 and 6 and the frequency spectra between the effective frequencies of these bands. We find that the median variability index steadily increases with the source-frame time lag increasing from 100 to 800 days, and that the frequency spectra of BL Lacs are significantly flatter than those of flat-spectrum radio quasars. We also show the global spectral energy distributions of our sources over 17 orders of magnitude in frequency.

Earth Global Reference Atmospheric Model (GRAM99): Short Course

NASA Technical Reports Server (NTRS)

Leslie, Fred W.; Justus, C. G.

2007-01-01

Earth-GRAM is a FORTRAN software package that can run on a variety of platforms including PC's. For any time and location in the Earth's atmosphere, Earth-GRAM provides values of atmospheric quantities such as temperature, pressure, density, winds, constituents, etc.. Dispersions (perturbations) of these parameters are also provided and have realistic correlations, means, and variances - useful for Monte Carlo analysis. Earth-GRAM is driven by observations including a tropospheric database available from the National Climatic Data Center. Although Earth-GRAM can be run in a "stand-alone" mode, many users incorporate it into their trajectory codes. The source code is distributed free-of-charge to eligible recipients.

Measuring Diagnoses: ICD Code Accuracy

PubMed Central

O'Malley, Kimberly J; Cook, Karon F; Price, Matt D; Wildes, Kimberly Raiford; Hurdle, John F; Ashton, Carol M

2005-01-01

Objective To examine potential sources of errors at each step of the described inpatient International Classification of Diseases (ICD) coding process. Data Sources/Study Setting The use of disease codes from the ICD has expanded from classifying morbidity and mortality information for statistical purposes to diverse sets of applications in research, health care policy, and health care finance. By describing a brief history of ICD coding, detailing the process for assigning codes, identifying where errors can be introduced into the process, and reviewing methods for examining code accuracy, we help code users more systematically evaluate code accuracy for their particular applications. Study Design/Methods We summarize the inpatient ICD diagnostic coding process from patient admission to diagnostic code assignment. We examine potential sources of errors at each step and offer code users a tool for systematically evaluating code accuracy. Principle Findings Main error sources along the “patient trajectory” include amount and quality of information at admission, communication among patients and providers, the clinician's knowledge and experience with the illness, and the clinician's attention to detail. Main error sources along the “paper trail” include variance in the electronic and written records, coder training and experience, facility quality-control efforts, and unintentional and intentional coder errors, such as misspecification, unbundling, and upcoding. Conclusions By clearly specifying the code assignment process and heightening their awareness of potential error sources, code users can better evaluate the applicability and limitations of codes for their particular situations. ICD codes can then be used in the most appropriate ways. PMID:16178999

Removing a barrier to computer-based outbreak and disease surveillance--the RODS Open Source Project.

PubMed

Espino, Jeremy U; Wagner, M; Szczepaniak, C; Tsui, F C; Su, H; Olszewski, R; Liu, Z; Chapman, W; Zeng, X; Ma, L; Lu, Z; Dara, J

2004-09-24

Computer-based outbreak and disease surveillance requires high-quality software that is well-supported and affordable. Developing software in an open-source framework, which entails free distribution and use of software and continuous, community-based software development, can produce software with such characteristics, and can do so rapidly. The objective of the Real-Time Outbreak and Disease Surveillance (RODS) Open Source Project is to accelerate the deployment of computer-based outbreak and disease surveillance systems by writing software and catalyzing the formation of a community of users, developers, consultants, and scientists who support its use. The University of Pittsburgh seeded the Open Source Project by releasing the RODS software under the GNU General Public License. An infrastructure was created, consisting of a website, mailing lists for developers and users, designated software developers, and shared code-development tools. These resources are intended to encourage growth of the Open Source Project community. Progress is measured by assessing website usage, number of software downloads, number of inquiries, number of system deployments, and number of new features or modules added to the code base. During September--November 2003, users generated 5,370 page views of the project website, 59 software downloads, 20 inquiries, one new deployment, and addition of four features. Thus far, health departments and companies have been more interested in using the software as is than in customizing or developing new features. The RODS laboratory anticipates that after initial installation has been completed, health departments and companies will begin to customize the software and contribute their enhancements to the public code base.

ESUSA: US endangered species distribution file

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nagy, J.; Calef, C.E.

1979-10-01

This report describes a file containing distribution data on endangered species of the United States of Federal concern pursuant to the Endangered Species Act of 1973. Included for each species are (a) the common name, (b) the scientific name, (c) the family, (d) the group (mammal, bird, etc.), (e) Fish and Wildlife Service (FWS) listing and recovery priorities, (f) the Federal legal status, (g) the geographic distribution by counties or islands, (h) Federal Register citations and (i) the sources of the information on distribution of the species. Status types are endangered, threatened, proposed, formally under review, candidate, deleted, and rejected.more » Distribution is by Federal Information Processing Standard (FIPS) county code and is of four types: designated critical habitat, present range, potential range, and historic range.« less

A systems neurophysiology approach to voluntary event coding.

PubMed

Petruo, Vanessa A; Stock, Ann-Kathrin; Münchau, Alexander; Beste, Christian

2016-07-15

Mechanisms responsible for the integration of perceptual events and appropriate actions (sensorimotor processes) have been subject to intense research. Different theoretical frameworks have been put forward with the "Theory of Event Coding (TEC)" being one of the most influential. In the current study, we focus on the concept of 'event files' within TEC and examine what sub-processes being dissociable by means of cognitive-neurophysiological methods are involved in voluntary event coding. This was combined with EEG source localization. We also introduce reward manipulations to delineate the neurophysiological sub-processes most relevant for performance variations during event coding. The results show that processes involved in voluntary event coding included predominantly stimulus categorization, feature unbinding and response selection, which were reflected by distinct neurophysiological processes (the P1, N2 and P3 ERPs). On a system's neurophysiological level, voluntary event-file coding is thus related to widely distributed parietal-medial frontal networks. Attentional selection processes (N1 ERP) turned out to be less important. Reward modulated stimulus categorization in parietal regions likely reflecting aspects of perceptual decision making but not in other processes. The perceptual categorization stage appears central for voluntary event-file coding. Copyright © 2016 Elsevier Inc. All rights reserved.

Ultraviolet spectrophotometry of three LINERs

NASA Technical Reports Server (NTRS)

Goodrich, R. W.; Keel, W. C.

1986-01-01

Three galaxies known to be LINERs were observed spectroscopically in the ultraviolet in an attempt to detect the presumed nonthermal continuum source thought to be the source of photoionization in the nuclei. NGC 4501 was found to be too faint for study with the IUE spectrographs, while NGC 5005 had an extended ultraviolet light profile. Comparison with the optical light profile of NGC 5005 indicates that the ultraviolet source is distributed spatially in the same manner as the optical starlight, probably indicating that the ultraviolet excess is due to a component of hot stars in the nucleus. These stars contribute detectable absorption features longward of 2500 A; together with optical data, the IUE spectra suggest a burst of star formation about 1 billion yr ago, with a lower rate continuing to produce a few OB stars. In NGC 4579, a point source contributing most of the ultraviolet excess is found that is much different than the optical light distribution. Furthermore, the ultraviolet to X-ray spectral index in NGC 4579 is 1.4, compatible with the UV to X-ray indices found for samples of Seyfert galaxies. This provides compelling evidence for the detection of the photoionizing continuum in NGC 4579 and draws the research fields of normal galaxies and active galactic nuclei closer together. The emission-line spectrum of NGC 4579 is compared with calculations from a photoionization code, CLOUDY, and several shock models. The photoionization code is found to give superior results, adding to the increasing weight of evidence that the LINER phenomenon is essentially a scaled-down version of the Seyfert phenomenon.

Some Experimental and Monte Carlo Investigations of the Plastic Scintillators for the Current Mode Measurements at Pulsed Neutron Sources

NASA Astrophysics Data System (ADS)

Rogov, A.; Pepyolyshev, Yu.; Carta, M.; d'Angelo, A.

Scintillation detector (SD) is widely used in neutron and gamma-spectrometry in a count mode. The organic scintillators for the count mode of the detector operation are investigated rather well. Usually, they are applied for measurement of amplitude and time distributions of pulses caused by single interaction events of neutrons or gamma's with scintillator material. But in a large area of scientific research scintillation detectors can alternatively be used on a current mode by recording the average current from the detector. For example,the measurements of the neutron pulse shape at the pulsed reactors or another pulsed neutron sources. So as to get a rather large volume of experimental data at pulsed neutron sources, it is necessary to use the current mode detector for registration of fast neutrons. Many parameters of the SD are changed with a transition from an accounting mode to current one. For example, the detector efficiency is different in counting and current modes. Many effects connected with time accuracy become substantial. Besides, for the registration of solely fast neutrons, as must be in many measurements, in the mixed radiation field of the pulsed neutron sources, SD efficiency has to be determined with a gamma-radiation shield present. Here is no calculations or experimental data on SD current mode operation up to now. The response functions of the detectors can be either measured in high-precision reference fields or calculated by a computer simulation. We have used the MCNP code [1] and carried out some experiments for investigation of the plastic performances in a current mode. There are numerous programs performing simulating similar to the MCNP code. For example, for neutrons there are [2-4], for photons - [5-8]. However, all known codes to use (SCINFUL, NRESP4, SANDYL, EGS49) have more stringent restrictions on the source, geometry and detector characteristics. In MCNP code a lot of these restrictions are absent and you need only to write special additions for proton and electron recoil and transfer energy to light output. These code modifications allow taking into account all processes in organic scintillator influence the light yield.

Topological Analysis of Wireless Networks (TAWN)

DTIC Science & Technology

2016-05-31

transmissions from any other node. Definition 1. A wireless network vulnerability is its susceptibility to becoming disconnected when a single source of...19b. TELEPHONE NUMBER (Include area code) 31-05-2016 FINAL REPORT 12-02-2015 -- 31-05-2016 Topological Analysis of Wireless Networks (TAWN) Robinson...Release, Distribution Unlimited) N/A The goal of this project was to develop topological methods to detect and localize vulnerabilities of wireless

Graphical Representation of Parallel Algorithmic Processes

DTIC Science & Technology

1990-12-01

interface with the AAARF main process . The source code for the AAARF class-common library is in the common subdi- rectory and consists of the following files... for public release; distribution unlimited AFIT/GCE/ENG/90D-07 Graphical Representation of Parallel Algorithmic Processes THESIS Presented to the...goal of this study is to develop an algorithm animation facility for parallel processes executing on different architectures, from multiprocessor

Operational rate-distortion performance for joint source and channel coding of images.

PubMed

Ruf, M J; Modestino, J W

1999-01-01

This paper describes a methodology for evaluating the operational rate-distortion behavior of combined source and channel coding schemes with particular application to images. In particular, we demonstrate use of the operational rate-distortion function to obtain the optimum tradeoff between source coding accuracy and channel error protection under the constraint of a fixed transmission bandwidth for the investigated transmission schemes. Furthermore, we develop information-theoretic bounds on performance for specific source and channel coding systems and demonstrate that our combined source-channel coding methodology applied to different schemes results in operational rate-distortion performance which closely approach these theoretical limits. We concentrate specifically on a wavelet-based subband source coding scheme and the use of binary rate-compatible punctured convolutional (RCPC) codes for transmission over the additive white Gaussian noise (AWGN) channel. Explicit results for real-world images demonstrate the efficacy of this approach.

GLACiAR, an Open-Source Python Tool for Simulations of Source Recovery and Completeness in Galaxy Surveys

NASA Astrophysics Data System (ADS)

Carrasco, D.; Trenti, M.; Mutch, S.; Oesch, P. A.

2018-06-01

The luminosity function is a fundamental observable for characterising how galaxies form and evolve throughout the cosmic history. One key ingredient to derive this measurement from the number counts in a survey is the characterisation of the completeness and redshift selection functions for the observations. In this paper, we present GLACiAR, an open python tool available on GitHub to estimate the completeness and selection functions in galaxy surveys. The code is tailored for multiband imaging surveys aimed at searching for high-redshift galaxies through the Lyman-break technique, but it can be applied broadly. The code generates artificial galaxies that follow Sérsic profiles with different indexes and with customisable size, redshift, and spectral energy distribution properties, adds them to input images, and measures the recovery rate. To illustrate this new software tool, we apply it to quantify the completeness and redshift selection functions for J-dropouts sources (redshift z 10 galaxies) in the Hubble Space Telescope Brightest of Reionizing Galaxies Survey. Our comparison with a previous completeness analysis on the same dataset shows overall agreement, but also highlights how different modelling assumptions for the artificial sources can impact completeness estimates.

NWChem: A comprehensive and scalable open-source solution for large scale molecular simulations

NASA Astrophysics Data System (ADS)

Valiev, M.; Bylaska, E. J.; Govind, N.; Kowalski, K.; Straatsma, T. P.; Van Dam, H. J. J.; Wang, D.; Nieplocha, J.; Apra, E.; Windus, T. L.; de Jong, W. A.

2010-09-01

The latest release of NWChem delivers an open-source computational chemistry package with extensive capabilities for large scale simulations of chemical and biological systems. Utilizing a common computational framework, diverse theoretical descriptions can be used to provide the best solution for a given scientific problem. Scalable parallel implementations and modular software design enable efficient utilization of current computational architectures. This paper provides an overview of NWChem focusing primarily on the core theoretical modules provided by the code and their parallel performance. Program summaryProgram title: NWChem Catalogue identifier: AEGI_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEGI_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Open Source Educational Community License No. of lines in distributed program, including test data, etc.: 11 709 543 No. of bytes in distributed program, including test data, etc.: 680 696 106 Distribution format: tar.gz Programming language: Fortran 77, C Computer: all Linux based workstations and parallel supercomputers, Windows and Apple machines Operating system: Linux, OS X, Windows Has the code been vectorised or parallelized?: Code is parallelized Classification: 2.1, 2.2, 3, 7.3, 7.7, 16.1, 16.2, 16.3, 16.10, 16.13 Nature of problem: Large-scale atomistic simulations of chemical and biological systems require efficient and reliable methods for ground and excited solutions of many-electron Hamiltonian, analysis of the potential energy surface, and dynamics. Solution method: Ground and excited solutions of many-electron Hamiltonian are obtained utilizing density-functional theory, many-body perturbation approach, and coupled cluster expansion. These solutions or a combination thereof with classical descriptions are then used to analyze potential energy surface and perform dynamical simulations. Additional comments: Full documentation is provided in the distribution file. This includes an INSTALL file giving details of how to build the package. A set of test runs is provided in the examples directory. The distribution file for this program is over 90 Mbytes and therefore is not delivered directly when download or Email is requested. Instead a html file giving details of how the program can be obtained is sent. Running time: Running time depends on the size of the chemical system, complexity of the method, number of cpu's and the computational task. It ranges from several seconds for serial DFT energy calculations on a few atoms to several hours for parallel coupled cluster energy calculations on tens of atoms or ab-initio molecular dynamics simulation on hundreds of atoms.

Final Technical Report for SBIR entitled Four-Dimensional Finite-Orbit-Width Fokker-Planck Code with Sources, for Neoclassical/Anomalous Transport Simulation of Ion and Electron Distributions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harvey, R. W.; Petrov, Yu. V.

2013-12-03

Within the US Department of Energy/Office of Fusion Energy magnetic fusion research program, there is an important whole-plasma-modeling need for a radio-frequency/neutral-beam-injection (RF/NBI) transport-oriented finite-difference Fokker-Planck (FP) code with combined capabilities for 4D (2R2V) geometry near the fusion plasma periphery, and computationally less demanding 3D (1R2V) bounce-averaged capabilities for plasma in the core of fusion devices. Demonstration of proof-of-principle achievement of this goal has been carried out in research carried out under Phase I of the SBIR award. Two DOE-sponsored codes, the CQL3D bounce-average Fokker-Planck code in which CompX has specialized, and the COGENT 4D, plasma edge-oriented Fokker-Planck code whichmore » has been constructed by Lawrence Livermore National Laboratory and Lawrence Berkeley Laboratory scientists, where coupled. Coupling was achieved by using CQL3D calculated velocity distributions including an energetic tail resulting from NBI, as boundary conditions for the COGENT code over the two-dimensional velocity space on a spatial interface (flux) surface at a given radius near the plasma periphery. The finite-orbit-width fast ions from the CQL3D distributions penetrated into the peripheral plasma modeled by the COGENT code. This combined code demonstrates the feasibility of the proposed 3D/4D code. By combining these codes, the greatest computational efficiency is achieved subject to present modeling needs in toroidally symmetric magnetic fusion devices. The more efficient 3D code can be used in its regions of applicability, coupled to the more computationally demanding 4D code in higher collisionality edge plasma regions where that extended capability is necessary for accurate representation of the plasma. More efficient code leads to greater use and utility of the model. An ancillary aim of the project is to make the combined 3D/4D code user friendly. Achievement of full-coupling of these two Fokker-Planck codes will advance computational modeling of plasma devices important to the USDOE magnetic fusion energy program, in particular the DIII-D tokamak at General Atomics, San Diego, the NSTX spherical tokamak at Princeton, New Jersey, and the MST reversed-field-pinch Madison, Wisconsin. The validation studies of the code against the experiments will improve understanding of physics important for magnetic fusion, and will increase our design capabilities for achieving the goals of the International Tokamak Experimental Reactor (ITER) project in which the US is a participant and which seeks to demonstrate at least a factor of five in fusion power production divided by input power.« less

Advancing Underwater Acoustic Communication for Autonomous Distributed Networks via Sparse Channel Sensing, Coding, and Navigation Support

DTIC Science & Technology

2014-09-30

underwater acoustic communication technologies for autonomous distributed underwater networks , through innovative signal processing, coding, and...4. TITLE AND SUBTITLE Advancing Underwater Acoustic Communication for Autonomous Distributed Networks via Sparse Channel Sensing, Coding, and...coding: 3) OFDM modulated dynamic coded cooperation in underwater acoustic channels; 3 Localization, Networking , and Testbed: 4) On-demand

SPIDERMAN: an open-source code to model phase curves and secondary eclipses

NASA Astrophysics Data System (ADS)

Louden, Tom; Kreidberg, Laura

2018-06-01

We present SPIDERMAN (Secondary eclipse and Phase curve Integrator for 2D tempERature MAppiNg), a fast code for calculating exoplanet phase curves and secondary eclipses with arbitrary surface brightness distributions in two dimensions. Using a geometrical algorithm, the code solves exactly the area of sections of the disc of the planet that are occulted by the star. The code is written in C with a user-friendly Python interface, and is optimized to run quickly, with no loss in numerical precision. Approximately 1000 models can be generated per second in typical use, making Markov Chain Monte Carlo analyses practicable. The modular nature of the code allows easy comparison of the effect of multiple different brightness distributions for the data set. As a test case, we apply the code to archival data on the phase curve of WASP-43b using a physically motivated analytical model for the two-dimensional brightness map. The model provides a good fit to the data; however, it overpredicts the temperature of the nightside. We speculate that this could be due to the presence of clouds on the nightside of the planet, or additional reflected light from the dayside. When testing a simple cloud model, we find that the best-fitting model has a geometric albedo of 0.32 ± 0.02 and does not require a hot nightside. We also test for variation of the map parameters as a function of wavelength and find no statistically significant correlations. SPIDERMAN is available for download at https://github.com/tomlouden/spiderman.

SENR /NRPy + : Numerical relativity in singular curvilinear coordinate systems

NASA Astrophysics Data System (ADS)

Ruchlin, Ian; Etienne, Zachariah B.; Baumgarte, Thomas W.

2018-03-01

We report on a new open-source, user-friendly numerical relativity code package called SENR /NRPy + . Our code extends previous implementations of the BSSN reference-metric formulation to a much broader class of curvilinear coordinate systems, making it ideally suited to modeling physical configurations with approximate or exact symmetries. In the context of modeling black hole dynamics, it is orders of magnitude more efficient than other widely used open-source numerical relativity codes. NRPy + provides a Python-based interface in which equations are written in natural tensorial form and output at arbitrary finite difference order as highly efficient C code, putting complex tensorial equations at the scientist's fingertips without the need for an expensive software license. SENR provides the algorithmic framework that combines the C codes generated by NRPy + into a functioning numerical relativity code. We validate against two other established, state-of-the-art codes, and achieve excellent agreement. For the first time—in the context of moving puncture black hole evolutions—we demonstrate nearly exponential convergence of constraint violation and gravitational waveform errors to zero as the order of spatial finite difference derivatives is increased, while fixing the numerical grids at moderate resolution in a singular coordinate system. Such behavior outside the horizons is remarkable, as numerical errors do not converge to zero near punctures, and all points along the polar axis are coordinate singularities. The formulation addresses such coordinate singularities via cell-centered grids and a simple change of basis that analytically regularizes tensor components with respect to the coordinates. Future plans include extending this formulation to allow dynamical coordinate grids and bispherical-like distribution of points to efficiently capture orbiting compact binary dynamics.

Smart photonic networks and computer security for image data

NASA Astrophysics Data System (ADS)

Campello, Jorge; Gill, John T.; Morf, Martin; Flynn, Michael J.

1998-02-01

Work reported here is part of a larger project on 'Smart Photonic Networks and Computer Security for Image Data', studying the interactions of coding and security, switching architecture simulations, and basic technologies. Coding and security: coding methods that are appropriate for data security in data fusion networks were investigated. These networks have several characteristics that distinguish them form other currently employed networks, such as Ethernet LANs or the Internet. The most significant characteristics are very high maximum data rates; predominance of image data; narrowcasting - transmission of data form one source to a designated set of receivers; data fusion - combining related data from several sources; simple sensor nodes with limited buffering. These characteristics affect both the lower level network design and the higher level coding methods.Data security encompasses privacy, integrity, reliability, and availability. Privacy, integrity, and reliability can be provided through encryption and coding for error detection and correction. Availability is primarily a network issue; network nodes must be protected against failure or routed around in the case of failure. One of the more promising techniques is the use of 'secret sharing'. We consider this method as a special case of our new space-time code diversity based algorithms for secure communication. These algorithms enable us to exploit parallelism and scalable multiplexing schemes to build photonic network architectures. A number of very high-speed switching and routing architectures and their relationships with very high performance processor architectures were studied. Indications are that routers for very high speed photonic networks can be designed using the very robust and distributed TCP/IP protocol, if suitable processor architecture support is available.

Continuation of research into language concepts for the mission support environment: Source code

NASA Technical Reports Server (NTRS)

Barton, Timothy J.; Ratner, Jeremiah M.

1991-01-01

Research into language concepts for the Mission Control Center is presented. A computer code for source codes is presented. The file contains the routines which allow source code files to be created and compiled. The build process assumes that all elements and the COMP exist in the current directory. The build process places as much code generation as possible on the preprocessor as possible. A summary is given of the source files as used and/or manipulated by the build routine.

Relevance and Effectiveness of the WHO Global Code Practice on the International Recruitment of Health Personnel--Ethical and Systems Perspectives.

PubMed

Brugha, Ruairí; Crowe, Sophie

2015-05-20

The relevance and effectiveness of the World Health Organization's (WHO's) Global Code of Practice on the International Recruitment of Health Personnel is being reviewed in 2015. The Code, which is a set of ethical norms and principles adopted by the World Health Assembly (WHA) in 2010, urges members states to train and retain the health personnel they need, thereby limiting demand for international migration, especially from the under-staffed health systems in low- and middle-income countries. Most countries failed to submit a first report in 2012 on implementation of the Code, including those source countries whose health systems are most under threat from the recruitment of their doctors and nurses, often to work in 4 major destination countries: the United States, United Kingdom, Canada and Australia. Political commitment by source country Ministers of Health needs to have been achieved at the May 2015 WHA to ensure better reporting by these countries on Code implementation for it to be effective. This paper uses ethics and health systems perspectives to analyse some of the drivers of international recruitment. The balance of competing ethics principles, which are contained in the Code's articles, reflects a tension that was evident during the drafting of the Code between 2007 and 2010. In 2007-2008, the right of health personnel to migrate was seen as a preeminent principle by US representatives on the Global Council which co-drafted the Code. Consensus on how to balance competing ethical principles--giving due recognition on the one hand to the obligations of health workers to the countries that trained them and the need for distributive justice given the global inequities of health workforce distribution in relation to need, and the right to migrate on the other hand--was only possible after President Obama took office in January 2009. It is in the interests of all countries to implement the Global Code and not just those that are losing their health personnel through international recruitment, given that it calls on all member states "to educate, retain and sustain a health workforce that is appropriate for their (need) ..." (Article 5.4), to ensure health systems' sustainability. However, in some wealthy destination countries, this means tackling national inequities and poorly designed health workforce strategies that result in foreign-trained doctors being recruited to work among disadvantaged populations and in primary care settings, allowing domestically trained doctors work in more attractive hospital settings. © 2015 by Kerman University of Medical Sciences.

Measuring diagnoses: ICD code accuracy.

PubMed

O'Malley, Kimberly J; Cook, Karon F; Price, Matt D; Wildes, Kimberly Raiford; Hurdle, John F; Ashton, Carol M

2005-10-01

To examine potential sources of errors at each step of the described inpatient International Classification of Diseases (ICD) coding process. The use of disease codes from the ICD has expanded from classifying morbidity and mortality information for statistical purposes to diverse sets of applications in research, health care policy, and health care finance. By describing a brief history of ICD coding, detailing the process for assigning codes, identifying where errors can be introduced into the process, and reviewing methods for examining code accuracy, we help code users more systematically evaluate code accuracy for their particular applications. We summarize the inpatient ICD diagnostic coding process from patient admission to diagnostic code assignment. We examine potential sources of errors at each step and offer code users a tool for systematically evaluating code accuracy. Main error sources along the "patient trajectory" include amount and quality of information at admission, communication among patients and providers, the clinician's knowledge and experience with the illness, and the clinician's attention to detail. Main error sources along the "paper trail" include variance in the electronic and written records, coder training and experience, facility quality-control efforts, and unintentional and intentional coder errors, such as misspecification, unbundling, and upcoding. By clearly specifying the code assignment process and heightening their awareness of potential error sources, code users can better evaluate the applicability and limitations of codes for their particular situations. ICD codes can then be used in the most appropriate ways.

FLUKA simulation of TEPC response to cosmic radiation.

PubMed

Beck, P; Ferrari, A; Pelliccioni, M; Rollet, S; Villari, R

2005-01-01

The aircrew exposure to cosmic radiation can be assessed by calculation with codes validated by measurements. However, the relationship between doses in the free atmosphere, as calculated by the codes and from results of measurements performed within the aircraft, is still unclear. The response of a tissue-equivalent proportional counter (TEPC) has already been simulated successfully by the Monte Carlo transport code FLUKA. Absorbed dose rate and ambient dose equivalent rate distributions as functions of lineal energy have been simulated for several reference sources and mixed radiation fields. The agreement between simulation and measurements has been well demonstrated. In order to evaluate the influence of aircraft structures on aircrew exposure assessment, the response of TEPC in the free atmosphere and on-board is now simulated. The calculated results are discussed and compared with other calculations and measurements.

Swan: A tool for porting CUDA programs to OpenCL

NASA Astrophysics Data System (ADS)

Harvey, M. J.; De Fabritiis, G.

2011-04-01

The use of modern, high-performance graphical processing units (GPUs) for acceleration of scientific computation has been widely reported. The majority of this work has used the CUDA programming model supported exclusively by GPUs manufactured by NVIDIA. An industry standardisation effort has recently produced the OpenCL specification for GPU programming. This offers the benefits of hardware-independence and reduced dependence on proprietary tool-chains. Here we describe a source-to-source translation tool, "Swan" for facilitating the conversion of an existing CUDA code to use the OpenCL model, as a means to aid programmers experienced with CUDA in evaluating OpenCL and alternative hardware. While the performance of equivalent OpenCL and CUDA code on fixed hardware should be comparable, we find that a real-world CUDA application ported to OpenCL exhibits an overall 50% increase in runtime, a reduction in performance attributable to the immaturity of contemporary compilers. The ported application is shown to have platform independence, running on both NVIDIA and AMD GPUs without modification. We conclude that OpenCL is a viable platform for developing portable GPU applications but that the more mature CUDA tools continue to provide best performance. Program summaryProgram title: Swan Catalogue identifier: AEIH_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEIH_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: GNU Public License version 2 No. of lines in distributed program, including test data, etc.: 17 736 No. of bytes in distributed program, including test data, etc.: 131 177 Distribution format: tar.gz Programming language: C Computer: PC Operating system: Linux RAM: 256 Mbytes Classification: 6.5 External routines: NVIDIA CUDA, OpenCL Nature of problem: Graphical Processing Units (GPUs) from NVIDIA are preferentially programed with the proprietary CUDA programming toolkit. An alternative programming model promoted as an industry standard, OpenCL, provides similar capabilities to CUDA and is also supported on non-NVIDIA hardware (including multicore ×86 CPUs, AMD GPUs and IBM Cell processors). The adaptation of a program from CUDA to OpenCL is relatively straightforward but laborious. The Swan tool facilitates this conversion. Solution method:Swan performs a translation of CUDA kernel source code into an OpenCL equivalent. It also generates the C source code for entry point functions, simplifying kernel invocation from the host program. A concise host-side API abstracts the CUDA and OpenCL APIs. A program adapted to use Swan has no dependency on the CUDA compiler for the host-side program. The converted program may be built for either CUDA or OpenCL, with the selection made at compile time. Restrictions: No support for CUDA C++ features Running time: Nominal

ALCBEAM - Neutral beam formation and propagation code for beam-based plasma diagnostics

NASA Astrophysics Data System (ADS)

Bespamyatnov, I. O.; Rowan, W. L.; Liao, K. T.

2012-03-01

ALCBEAM is a new three-dimensional neutral beam formation and propagation code. It was developed to support the beam-based diagnostics installed on the Alcator C-Mod tokamak. The purpose of the code is to provide reliable estimates of the local beam equilibrium parameters: such as beam energy fractions, density profiles and excitation populations. The code effectively unifies the ion beam formation, extraction and neutralization processes with beam attenuation and excitation in plasma and neutral gas and beam stopping by the beam apertures. This paper describes the physical processes interpreted and utilized by the code, along with exploited computational methods. The description is concluded by an example simulation of beam penetration into plasma of Alcator C-Mod. The code is successfully being used in Alcator C-Mod tokamak and expected to be valuable in the support of beam-based diagnostics in most other tokamak environments. Program summaryProgram title: ALCBEAM Catalogue identifier: AEKU_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEKU_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 66 459 No. of bytes in distributed program, including test data, etc.: 7 841 051 Distribution format: tar.gz Programming language: IDL Computer: Workstation, PC Operating system: Linux RAM: 1 GB Classification: 19.2 Nature of problem: Neutral beams are commonly used to heat and/or diagnose high-temperature magnetically-confined laboratory plasmas. An accurate neutral beam characterization is required for beam-based measurements of plasma properties. Beam parameters such as density distribution, energy composition, and atomic excited populations of the beam atoms need to be known. Solution method: A neutral beam is initially formed as an ion beam which is extracted from the ion source by high voltage applied to the extraction and accelerating grids. The current distribution of a single beamlet emitted from a single pore of IOS depends on the shape of the plasma boundary in the emission region. Total beam extracted by IOS is calculated at every point of 3D mesh as sum of all contributions from each grid pore. The code effectively unifies the ion beam formation, extraction and neutralization processes with neutral beam attenuation and excitation in plasma and neutral gas and beam stopping by the beam apertures. Running time: 10 min for a standard run.

Developing open-source codes for electromagnetic geophysics using industry support

NASA Astrophysics Data System (ADS)

Key, K.

2017-12-01

Funding for open-source software development in academia often takes the form of grants and fellowships awarded by government bodies and foundations where there is no conflict-of-interest between the funding entity and the free dissemination of the open-source software products. Conversely, funding for open-source projects in the geophysics industry presents challenges to conventional business models where proprietary licensing offers value that is not present in open-source software. Such proprietary constraints make it easier to convince companies to fund academic software development under exclusive software distribution agreements. A major challenge for obtaining commercial funding for open-source projects is to offer a value proposition that overcomes the criticism that such funding is a give-away to the competition. This work draws upon a decade of experience developing open-source electromagnetic geophysics software for the oil, gas and minerals exploration industry, and examines various approaches that have been effective for sustaining industry sponsorship.

IEEE 1547 Standards Advancing Grid Modernization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Basso, Thomas; Chakraborty, Sudipta; Hoke, Andy

Technology advances including development of advanced distributed energy resources (DER) and grid-integrated operations and controls functionalities have surpassed the requirements in current standards and codes for DER interconnection with the distribution grid. The full revision of IEEE Standards 1547 (requirements for DER-grid interconnection and interoperability) and 1547.1 (test procedures for conformance to 1547) are establishing requirements and best practices for state-of-the-art DER including variable renewable energy sources. The revised standards will also address challenges associated with interoperability and transmission-level effects, in addition to strictly addressing the distribution grid needs. This paper provides the status and future direction of the ongoingmore » development focus for the 1547 standards.« less

Seismic Hazard analysis of Adjaria Region in Georgia

NASA Astrophysics Data System (ADS)

Jorjiashvili, Nato; Elashvili, Mikheil

2014-05-01

The most commonly used approach to determining seismic-design loads for engineering projects is probabilistic seismic-hazard analysis (PSHA). The primary output from a PSHA is a hazard curve showing the variation of a selected ground-motion parameter, such as peak ground acceleration (PGA) or spectral acceleration (SA), against the annual frequency of exceedance (or its reciprocal, return period). The design value is the ground-motion level that corresponds to a preselected design return period. For many engineering projects, such as standard buildings and typical bridges, the seismic loading is taken from the appropriate seismic-design code, the basis of which is usually a PSHA. For more important engineering projects— where the consequences of failure are more serious, such as dams and chemical plants—it is more usual to obtain the seismic-design loads from a site-specific PSHA, in general, using much longer return periods than those governing code based design. Calculation of Probabilistic Seismic Hazard was performed using Software CRISIS2007 by Ordaz, M., Aguilar, A., and Arboleda, J., Instituto de Ingeniería, UNAM, Mexico. CRISIS implements a classical probabilistic seismic hazard methodology where seismic sources can be modelled as points, lines and areas. In the case of area sources, the software offers an integration procedure that takes advantage of a triangulation algorithm used for seismic source discretization. This solution improves calculation efficiency while maintaining a reliable description of source geometry and seismicity. Additionally, supplementary filters (e.g. fix a sitesource distance that excludes from calculation sources at great distance) allow the program to balance precision and efficiency during hazard calculation. Earthquake temporal occurrence is assumed to follow a Poisson process, and the code facilitates two types of MFDs: a truncated exponential Gutenberg-Richter [1944] magnitude distribution and a characteristic magnitude distribution [Youngs and Coppersmith, 1985]. Notably, the software can deal with uncertainty in the seismicity input parameters such as maximum magnitude value. CRISIS offers a set of built-in GMPEs, as well as the possibility of defining new ones by providing information in a tabular format. Our study shows that in case of Ajaristkali HPP study area, significant contribution to Seismic Hazard comes from local sources with quite low Mmax values, thus these two attenuation lows give us quite different PGA and SA values.

Public domain optical character recognition

NASA Astrophysics Data System (ADS)

Garris, Michael D.; Blue, James L.; Candela, Gerald T.; Dimmick, Darrin L.; Geist, Jon C.; Grother, Patrick J.; Janet, Stanley A.; Wilson, Charles L.

1995-03-01

A public domain document processing system has been developed by the National Institute of Standards and Technology (NIST). The system is a standard reference form-based handprint recognition system for evaluating optical character recognition (OCR), and it is intended to provide a baseline of performance on an open application. The system's source code, training data, performance assessment tools, and type of forms processed are all publicly available. The system recognizes the handprint entered on handwriting sample forms like the ones distributed with NIST Special Database 1. From these forms, the system reads hand-printed numeric fields, upper and lowercase alphabetic fields, and unconstrained text paragraphs comprised of words from a limited-size dictionary. The modular design of the system makes it useful for component evaluation and comparison, training and testing set validation, and multiple system voting schemes. The system contains a number of significant contributions to OCR technology, including an optimized probabilistic neural network (PNN) classifier that operates a factor of 20 times faster than traditional software implementations of the algorithm. The source code for the recognition system is written in C and is organized into 11 libraries. In all, there are approximately 19,000 lines of code supporting more than 550 subroutines. Source code is provided for form registration, form removal, field isolation, field segmentation, character normalization, feature extraction, character classification, and dictionary-based postprocessing. The recognition system has been successfully compiled and tested on a host of UNIX workstations. This paper gives an overview of the recognition system's software architecture, including descriptions of the various system components along with timing and accuracy statistics.

The international migration of dentists: directions for research and policy.

PubMed

Balasubramanian, Madhan; Brennan, David Simon; Spencer, A John; Short, Stephanie Doris

2016-08-01

In 2010, the World Health Organization Global Code of Practice for International Recruitment of Health Personnel (the WHO Code) was adopted by the 193 Member States of the WHO. The WHO Code is a tool for global diplomacy, providing a policy framework to address the challenges involved in managing dentist migration, as well as improving the retention of dental personnel in source countries. The WHO Code recognizes the importance of migrant dentist data to support migration polices; minimum data on the inflows, outflows and stock of dentists are vital. Data on reasons for dentist migration, job satisfaction, cultural adaptation issues, geographic distribution and practice patterns in the destination country are important for any policy analysis on dentist migration. Key challenges in the implementation of the WHO Code include the necessity to coordinate with multiple stakeholders and the lack of integrated data on dentist migration and the lack of shared understanding of the interrelatedness of workforce migration, needs and planning. The profession of dentistry also requires coordination with a number of private and nongovernmental organizations. Many migrant dentist source countries, in African and the South-Asian WHO Regions, are in the early stages of building capacity in dentist migration data collection and research systems. Due to these shortcomings, it is prudent that developed countries take the initiative to pursue further research into the migration issue and respond to this global challenge. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Neutronic calculation of fast reactors by the EUCLID/V1 integrated code

NASA Astrophysics Data System (ADS)

Koltashev, D. A.; Stakhanova, A. A.

2017-01-01

This article considers neutronic calculation of a fast-neutron lead-cooled reactor BREST-OD-300 by the EUCLID/V1 integrated code. The main goal of development and application of integrated codes is a nuclear power plant safety justification. EUCLID/V1 is integrated code designed for coupled neutronics, thermomechanical and thermohydraulic fast reactor calculations under normal and abnormal operating conditions. EUCLID/V1 code is being developed in the Nuclear Safety Institute of the Russian Academy of Sciences. The integrated code has a modular structure and consists of three main modules: thermohydraulic module HYDRA-IBRAE/LM/V1, thermomechanical module BERKUT and neutronic module DN3D. In addition, the integrated code includes databases with fuel, coolant and structural materials properties. Neutronic module DN3D provides full-scale simulation of neutronic processes in fast reactors. Heat sources distribution, control rods movement, reactivity level changes and other processes can be simulated. Neutron transport equation in multigroup diffusion approximation is solved. This paper contains some calculations implemented as a part of EUCLID/V1 code validation. A fast-neutron lead-cooled reactor BREST-OD-300 transient simulation (fuel assembly floating, decompression of passive feedback system channel) and cross-validation with MCU-FR code results are presented in this paper. The calculations demonstrate EUCLID/V1 code application for BREST-OD-300 simulating and safety justification.

Poster - Thur Eve - 06: Comparison of an open source genetic algorithm to the commercially used IPSA for generation of seed distributions in LDR prostate brachytherapy.

PubMed

McGeachy, P; Khan, R

2012-07-01

In early stage prostate cancer, low dose rate (LDR) prostate brachytherapy is a favorable treatment modality, where small radioactive seeds are permanently implanted throughout the prostate. Treatment centres currently rely on a commercial optimization algorithm, IPSA, to generate seed distributions for treatment plans. However, commercial software does not allow the user access to the source code, thus reducing the flexibility for treatment planning and impeding any implementation of new and, perhaps, improved clinical techniques. An open source genetic algorithm (GA) has been encoded in MATLAB to generate seed distributions for a simplified prostate and urethra model. To assess the quality of the seed distributions created by the GA, both the GA and IPSA were used to generate seed distributions for two clinically relevant scenarios and the quality of the GA distributions relative to IPSA distributions and clinically accepted standards for seed distributions was investigated. The first clinically relevant scenario involved generating seed distributions for three different prostate volumes (19.2 cc, 32.4 cc, and 54.7 cc). The second scenario involved generating distributions for three separate seed activities (0.397 mCi, 0.455 mCi, and 0.5 mCi). Both GA and IPSA met the clinically accepted criteria for the two scenarios, where distributions produced by the GA were comparable to IPSA in terms of full coverage of the prostate by the prescribed dose, and minimized dose to the urethra, which passed straight through the prostate. Further, the GA offered improved reduction of high dose regions (i.e hot spots) within the planned target volume. © 2012 American Association of Physicists in Medicine.

Modelisation and distribution of neutron flux in radium-beryllium source (226Ra-Be)

NASA Astrophysics Data System (ADS)

Didi, Abdessamad; Dadouch, Ahmed; Jai, Otman

2017-09-01

Using the Monte Carlo N-Particle code (MCNP-6), to analyze the thermal, epithermal and fast neutron fluxes, of 3 millicuries of radium-beryllium, for determine the qualitative and quantitative of many materials, using method of neutron activation analysis. Radium-beryllium source of neutron is established to practical work and research in nuclear field. The main objective of this work was to enable us harness the profile flux of radium-beryllium irradiation, this theoretical study permits to discuss the design of the optimal irradiation and performance for increased the facility research and education of nuclear physics.

3Dmol.js: molecular visualization with WebGL.

PubMed

Rego, Nicholas; Koes, David

2015-04-15

3Dmol.js is a modern, object-oriented JavaScript library that uses the latest web technologies to provide interactive, hardware-accelerated three-dimensional representations of molecular data without the need to install browser plugins or Java. 3Dmol.js provides a full featured API for developers as well as a straightforward declarative interface that lets users easily share and embed molecular data in websites. 3Dmol.js is distributed under the permissive BSD open source license. Source code and documentation can be found at http://3Dmol.csb.pitt.edu dkoes@pitt.edu. © The Author 2014. Published by Oxford University Press.

A Multiphysics and Multiscale Software Environment for Modeling Astrophysical Systems

NASA Astrophysics Data System (ADS)

Portegies Zwart, Simon; McMillan, Steve; O'Nualláin, Breanndán; Heggie, Douglas; Lombardi, James; Hut, Piet; Banerjee, Sambaran; Belkus, Houria; Fragos, Tassos; Fregeau, John; Fuji, Michiko; Gaburov, Evghenii; Glebbeek, Evert; Groen, Derek; Harfst, Stefan; Izzard, Rob; Jurić, Mario; Justham, Stephen; Teuben, Peter; van Bever, Joris; Yaron, Ofer; Zemp, Marcel

We present MUSE, a software framework for tying together existing computational tools for different astrophysical domains into a single multiphysics, multiscale workload. MUSE facilitates the coupling of existing codes written in different languages by providing inter-language tools and by specifying an interface between each module and the framework that represents a balance between generality and computational efficiency. This approach allows scientists to use combinations of codes to solve highly-coupled problems without the need to write new codes for other domains or significantly alter their existing codes. MUSE currently incorporates the domains of stellar dynamics, stellar evolution and stellar hydrodynamics for a generalized stellar systems workload. MUSE has now reached a "Noah's Ark" milestone, with two available numerical solvers for each domain. MUSE can treat small stellar associations, galaxies and everything in between, including planetary systems, dense stellar clusters and galactic nuclei. Here we demonstrate an examples calculated with MUSE: the merger of two galaxies. In addition we demonstrate the working of MUSE on a distributed computer. The current MUSE code base is publicly available as open source at http://muse.li.

Schroedinger’s Code: A Preliminary Study on Research Source Code Availability and Link Persistence in Astrophysics

NASA Astrophysics Data System (ADS)

Allen, Alice; Teuben, Peter J.; Ryan, P. Wesley

2018-05-01

We examined software usage in a sample set of astrophysics research articles published in 2015 and searched for the source codes for the software mentioned in these research papers. We categorized the software to indicate whether the source code is available for download and whether there are restrictions to accessing it, and if the source code is not available, whether some other form of the software, such as a binary, is. We also extracted hyperlinks from one journal’s 2015 research articles, as links in articles can serve as an acknowledgment of software use and lead to the data used in the research, and tested them to determine which of these URLs are still accessible. For our sample of 715 software instances in the 166 articles we examined, we were able to categorize 418 records as according to whether source code was available and found that 285 unique codes were used, 58% of which offered the source code for download. Of the 2558 hyperlinks extracted from 1669 research articles, at best, 90% of them were available over our testing period.

An experimental MOSFET approach to characterize (192)Ir HDR source anisotropy.

PubMed

Toye, W C; Das, K R; Todd, S P; Kenny, M B; Franich, R D; Johnston, P N

2007-09-07

The dose anisotropy around a (192)Ir HDR source in a water phantom has been measured using MOSFETs as relative dosimeters. In addition, modeling using the EGSnrc code has been performed to provide a complete dose distribution consistent with the MOSFET measurements. Doses around the Nucletron 'classic' (192)Ir HDR source were measured for a range of radial distances from 5 to 30 mm within a 40 x 30 x 30 cm(3) water phantom, using a TN-RD-50 MOSFET dosimetry system with an active area of 0.2 mm by 0.2 mm. For each successive measurement a linear stepper capable of movement in intervals of 0.0125 mm re-positioned the MOSFET at the required radial distance, while a rotational stepper enabled angular displacement of the source at intervals of 0.9 degrees . The source-dosimeter arrangement within the water phantom was modeled using the standardized cylindrical geometry of the DOSRZnrc user code. In general, the measured relative anisotropy at each radial distance from 5 mm to 30 mm is in good agreement with the EGSnrc simulations, benchmark Monte Carlo simulation and TLD measurements where they exist. The experimental approach employing a MOSFET detection system of small size, high spatial resolution and fast read out capability allowed a practical approach to the determination of dose anisotropy around a HDR source.

Automated Concurrent Blackboard System Generation in C++

NASA Technical Reports Server (NTRS)

Kaplan, J. A.; McManus, J. W.; Bynum, W. L.

1999-01-01

In his 1992 Ph.D. thesis, "Design and Analysis Techniques for Concurrent Blackboard Systems", John McManus defined several performance metrics for concurrent blackboard systems and developed a suite of tools for creating and analyzing such systems. These tools allow a user to analyze a concurrent blackboard system design and predict the performance of the system before any code is written. The design can be modified until simulated performance is satisfactory. Then, the code generator can be invoked to generate automatically all of the code required for the concurrent blackboard system except for the code implementing the functionality of each knowledge source. We have completed the port of the source code generator and a simulator for a concurrent blackboard system. The source code generator generates the necessary C++ source code to implement the concurrent blackboard system using Parallel Virtual Machine (PVM) running on a heterogeneous network of UNIX(trademark) workstations. The concurrent blackboard simulator uses the blackboard specification file to predict the performance of the concurrent blackboard design. The only part of the source code for the concurrent blackboard system that the user must supply is the code implementing the functionality of the knowledge sources.

DLRS: gene tree evolution in light of a species tree.

PubMed

Sjöstrand, Joel; Sennblad, Bengt; Arvestad, Lars; Lagergren, Jens

2012-11-15

PrIME-DLRS (or colloquially: 'Delirious') is a phylogenetic software tool to simultaneously infer and reconcile a gene tree given a species tree. It accounts for duplication and loss events, a relaxed molecular clock and is intended for the study of homologous gene families, for example in a comparative genomics setting involving multiple species. PrIME-DLRS uses a Bayesian MCMC framework, where the input is a known species tree with divergence times and a multiple sequence alignment, and the output is a posterior distribution over gene trees and model parameters. PrIME-DLRS is available for Java SE 6+ under the New BSD License, and JAR files and source code can be downloaded from http://code.google.com/p/jprime/. There is also a slightly older C++ version available as a binary package for Ubuntu, with download instructions at http://prime.sbc.su.se. The C++ source code is available upon request. joel.sjostrand@scilifelab.se or jens.lagergren@scilifelab.se. PrIME-DLRS is based on a sound probabilistic model (Åkerborg et al., 2009) and has been thoroughly validated on synthetic and biological datasets (Supplementary Material online).

Analysis of a Neutronic Experiment on a Simulated Mercury Spallation Neutron Target Assembly Bombarded by Giga-Electron-Volt Protons

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maekawa, Fujio; Meigo, Shin-ichiro; Kasugai, Yoshimi

2005-05-15

A neutronic benchmark experiment on a simulated spallation neutron target assembly was conducted by using the Alternating Gradient Synchrotron at Brookhaven National Laboratory and was analyzed to investigate the prediction capability of Monte Carlo simulation codes used in neutronic designs of spallation neutron sources. The target assembly consisting of a mercury target, a light water moderator, and a lead reflector was bombarded by 1.94-, 12-, and 24-GeV protons, and the fast neutron flux distributions around the target and the spectra of thermal neutrons leaking from the moderator were measured in the experiment. In this study, the Monte Carlo particle transportmore » simulation codes NMTC/JAM, MCNPX, and MCNP-4A with associated cross-section data in JENDL and LA-150 were verified based on benchmark analysis of the experiment. As a result, all the calculations predicted the measured quantities adequately; calculated integral fluxes of fast and thermal neutrons agreed approximately within {+-}40% with the experiments although the overall energy range encompassed more than 12 orders of magnitude. Accordingly, it was concluded that these simulation codes and cross-section data were adequate for neutronics designs of spallation neutron sources.« less

BioNetFit: a fitting tool compatible with BioNetGen, NFsim and distributed computing environments

PubMed Central

Thomas, Brandon R.; Chylek, Lily A.; Colvin, Joshua; Sirimulla, Suman; Clayton, Andrew H.A.; Hlavacek, William S.; Posner, Richard G.

2016-01-01

Summary: Rule-based models are analyzed with specialized simulators, such as those provided by the BioNetGen and NFsim open-source software packages. Here, we present BioNetFit, a general-purpose fitting tool that is compatible with BioNetGen and NFsim. BioNetFit is designed to take advantage of distributed computing resources. This feature facilitates fitting (i.e. optimization of parameter values for consistency with data) when simulations are computationally expensive. Availability and implementation: BioNetFit can be used on stand-alone Mac, Windows/Cygwin, and Linux platforms and on Linux-based clusters running SLURM, Torque/PBS, or SGE. The BioNetFit source code (Perl) is freely available (http://bionetfit.nau.edu). Supplementary information: Supplementary data are available at Bioinformatics online. Contact: bionetgen.help@gmail.com PMID:26556387

You've Written a Cool Astronomy Code! Now What Do You Do with It?

NASA Astrophysics Data System (ADS)

Allen, Alice; Accomazzi, A.; Berriman, G. B.; DuPrie, K.; Hanisch, R. J.; Mink, J. D.; Nemiroff, R. J.; Shamir, L.; Shortridge, K.; Taylor, M. B.; Teuben, P. J.; Wallin, J. F.

2014-01-01

Now that you've written a useful astronomy code for your soon-to-be-published research, you have to figure out what you want to do with it. Our suggestion? Share it! This presentation highlights the means and benefits of sharing your code. Make your code citable -- submit it to the Astrophysics Source Code Library and have it indexed by ADS! The Astrophysics Source Code Library (ASCL) is a free online registry of source codes of interest to astronomers and astrophysicists. With over 700 codes, it is continuing its rapid growth, with an average of 17 new codes a month. The editors seek out codes for inclusion; indexing by ADS improves the discoverability of codes and provides a way to cite codes as separate entries, especially codes without papers that describe them.

NOTE: Development of modified voxel phantoms for the numerical dosimetric reconstruction of radiological accidents involving external sources: implementation in SESAME tool

NASA Astrophysics Data System (ADS)

Courageot, Estelle; Sayah, Rima; Huet, Christelle

2010-05-01

Estimating the dose distribution in a victim's body is a relevant indicator in assessing biological damage from exposure in the event of a radiological accident caused by an external source. When the dose distribution is evaluated with a numerical anthropomorphic model, the posture and morphology of the victim have to be reproduced as realistically as possible. Several years ago, IRSN developed a specific software application, called the simulation of external source accident with medical images (SESAME), for the dosimetric reconstruction of radiological accidents by numerical simulation. This tool combines voxel geometry and the MCNP(X) Monte Carlo computer code for radiation-material interaction. This note presents a new functionality in this software that enables the modelling of a victim's posture and morphology based on non-uniform rational B-spline (NURBS) surfaces. The procedure for constructing the modified voxel phantoms is described, along with a numerical validation of this new functionality using a voxel phantom of the RANDO tissue-equivalent physical model.

Development of modified voxel phantoms for the numerical dosimetric reconstruction of radiological accidents involving external sources: implementation in SESAME tool.

PubMed

Courageot, Estelle; Sayah, Rima; Huet, Christelle

2010-05-07

Estimating the dose distribution in a victim's body is a relevant indicator in assessing biological damage from exposure in the event of a radiological accident caused by an external source. When the dose distribution is evaluated with a numerical anthropomorphic model, the posture and morphology of the victim have to be reproduced as realistically as possible. Several years ago, IRSN developed a specific software application, called the simulation of external source accident with medical images (SESAME), for the dosimetric reconstruction of radiological accidents by numerical simulation. This tool combines voxel geometry and the MCNP(X) Monte Carlo computer code for radiation-material interaction. This note presents a new functionality in this software that enables the modelling of a victim's posture and morphology based on non-uniform rational B-spline (NURBS) surfaces. The procedure for constructing the modified voxel phantoms is described, along with a numerical validation of this new functionality using a voxel phantom of the RANDO tissue-equivalent physical model.

Computational studies for a multiple-frequency electron cyclotron resonance ion source (abstract)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alton, G.D.

1996-03-01

The number density of electrons, the energy (electron temperature), and energy distribution are three of the fundamental properties which govern the performance of electron cyclotron resonance (ECR) ion sources in terms of their capability to produce high charge state ions. The maximum electron energy is affected by several processes including the ability of the plasma to absorb power. In principle, the performances of an ECR ion source can be realized by increasing the physical size of the ECR zone in relation to the total plasma volume. The ECR zones can be increased either in the spatial or frequency domains inmore » any ECR ion source based on B-minimum plasma confinement principles. The former technique requires the design of a carefully tailored magnetic field geometry so that the central region of the plasma volume is a large, uniformly distributed plasma volume which surrounds the axis of symmetry, as proposed in Ref. . Present art forms of the ECR source utilize single frequency microwave power supplies to maintain the plasma discharge; because the magnetic field distribution continually changes in this source design, the ECR zones are relegated to thin {open_quote}{open_quote}surfaces{close_quote}{close_quote} which surround the axis of symmetry. As a consequence of the small ECR zone in relation to the total plasma volume, the probability for stochastic heating of the electrons is quite low, thereby compromising the source performance. This handicap can be overcome by use of broadband, multiple frequency microwave power as evidenced by the enhanced performances of the CAPRICE and AECR ion sources when two frequency microwave power was utilized. We have used particle-in-cell codes to simulate the magnetic field distributions in these sources and to demonstrate the advantages of using multiple, discrete frequencies over single frequencies to power conventional ECR ion sources. (Abstract Truncated)« less

Computational mechanics analysis tools for parallel-vector supercomputers

NASA Technical Reports Server (NTRS)

Storaasli, Olaf O.; Nguyen, Duc T.; Baddourah, Majdi; Qin, Jiangning

1993-01-01

Computational algorithms for structural analysis on parallel-vector supercomputers are reviewed. These parallel algorithms, developed by the authors, are for the assembly of structural equations, 'out-of-core' strategies for linear equation solution, massively distributed-memory equation solution, unsymmetric equation solution, general eigensolution, geometrically nonlinear finite element analysis, design sensitivity analysis for structural dynamics, optimization search analysis and domain decomposition. The source code for many of these algorithms is available.

An Extensible NetLogo Model for Visualizing Message Routing Protocols

DTIC Science & Technology

2017-08-01

the hard sciences to the social sciences to computer-generated art. NetLogo represents the world as a set of...describe the model is shown here; for the supporting methods , refer to the source code. Approved for public release; distribution is unlimited. 4 iv...if ticks - last-inject > time-to-inject [inject] if run# > #runs [stop] end Next, we present some basic statistics collected for the

Enabling Incremental Iterative Development at Scale: Quality Attribute Refinement and Allocation in Practice

DTIC Science & Technology

2015-06-01

abstract constraints along six dimen- sions for expansion: user, actions, data , business rules, interfaces, and quality attributes [Gottesdiener 2010...relevant open source systems. For example, the CONNECT and HADOOP Distributed File System (HDFS) projects have many user stories that deal with...Iteration Zero involves architecture planning before writing any code. An overly long Iteration Zero is equivalent to the dysfunctional “ Big Up-Front

Data Release of UV to Submillimeter Broadband Fluxes for Simulated Galaxies from the EAGLE Project

NASA Astrophysics Data System (ADS)

Camps, Peter; Trčka, Ana; Trayford, James; Baes, Maarten; Theuns, Tom; Crain, Robert A.; McAlpine, Stuart; Schaller, Matthieu; Schaye, Joop

2018-02-01

We present dust-attenuated and dust emission fluxes for sufficiently resolved galaxies in the EAGLE suite of cosmological hydrodynamical simulations, calculated with the SKIRT radiative transfer code. The post-processing procedure includes specific components for star formation regions, stellar sources, and diffuse dust and takes into account stochastic heating of dust grains to obtain realistic broadband fluxes in the wavelength range from ultraviolet to submillimeter. The mock survey includes nearly half a million simulated galaxies with stellar masses above {10}8.5 {M}ȯ across six EAGLE models. About two-thirds of these galaxies, residing in 23 redshift bins up to z = 6, have a sufficiently resolved metallic gas distribution to derive meaningful dust attenuation and emission, with the important caveat that the same dust properties were used at all redshifts. These newly released data complement the already publicly available information about the EAGLE galaxies, which includes intrinsic properties derived by aggregating the properties of the smoothed particles representing matter in the simulation. We further provide an open-source framework of Python procedures for post-processing simulated galaxies with the radiative transfer code SKIRT. The framework allows any third party to calculate synthetic images, spectral energy distributions, and broadband fluxes for EAGLE galaxies, taking into account the effects of dust attenuation and emission.

On the continuity of the stationary state distribution of DPCM

NASA Astrophysics Data System (ADS)

Naraghi-Pour, Morteza; Neuhoff, David L.

1990-03-01

Continuity and singularity properties of the stationary state distribution of differential pulse code modulation (DPCM) are explored. Two-level DPCM (i.e., delta modulation) operating on a first-order autoregressive source is considered, and it is shown that, when the magnitude of the DPCM prediciton coefficient is between zero and one-half, the stationary state distribution is singularly continuous; i.e., it is not discrete but concentrates on an uncountable set with a Lebesgue measure of zero. Consequently, it cannot be represented with a probability density function. For prediction coefficients with magnitude greater than or equal to one-half, the distribution is pure, i.e., either absolutely continuous and representable with a density function, or singular. This problem is compared to the well-known and still substantially unsolved problem of symmetric Bernoulli convolutions.

Intra-Beam and Touschek Scattering Computations for Beam with Non-Gaussian Longitudinal Distributions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xiao, A.; Borland, M.

Both intra-beamscattering (IBS) and the Touschek effect become prominent formulti-bend-achromat- (MBA-) based ultra-low-emittance storage rings. To mitigate the transverse emittance degradation and obtain a reasonably long beam lifetime, a higher harmonic rf cavity (HHC) is often proposed to lengthen the bunch. The use of such a cavity results in a non-gaussian longitudinal distribution. However, common methods for computing IBS and Touschek scattering assume Gaussian distributions. Modifications have been made to several simulation codes that are part of the elegant [1] toolkit to allow these computations for arbitrary longitudinal distributions. After describing thesemodifications, we review the results of detailed simulations formore » the proposed hybrid seven-bend-achromat (H7BA) upgrade lattice [2] for the Advanced Photon Source.« less

Effect of high energy electrons on H{sup −} production and destruction in a high current DC negative ion source for cyclotron

DOE Office of Scientific and Technical Information (OSTI.GOV)

Onai, M., E-mail: onai@ppl.appi.keio.ac.jp; Fujita, S.; Hatayama, A.

2016-02-15

Recently, a filament driven multi-cusp negative ion source has been developed for proton cyclotrons in medical applications. In this study, numerical modeling of the filament arc-discharge source plasma has been done with kinetic modeling of electrons in the ion source plasmas by the multi-cusp arc-discharge code and zero dimensional rate equations for hydrogen molecules and negative ions. In this paper, main focus is placed on the effects of the arc-discharge power on the electron energy distribution function and the resultant H{sup −} production. The modelling results reasonably explains the dependence of the H{sup −} extraction current on the arc-discharge powermore » in the experiments.« less

User Manual and Source Code for a LAMMPS Implementation of Constant Energy Dissipative Particle Dynamics (DPD-E)

DTIC Science & Technology

2014-06-01

User Manual and Source Code for a LAMMPS Implementation of Constant Energy Dissipative Particle Dynamics (DPD-E) by James P. Larentzos...Laboratory Aberdeen Proving Ground, MD 21005-5069 ARL-SR-290 June 2014 User Manual and Source Code for a LAMMPS Implementation of Constant...3. DATES COVERED (From - To) September 2013–February 2014 4. TITLE AND SUBTITLE User Manual and Source Code for a LAMMPS Implementation of

Dark Energy Survey Year 1 results: cross-correlation redshifts - methods and systematics characterization

NASA Astrophysics Data System (ADS)

Gatti, M.; Vielzeuf, P.; Davis, C.; Cawthon, R.; Rau, M. M.; DeRose, J.; De Vicente, J.; Alarcon, A.; Rozo, E.; Gaztanaga, E.; Hoyle, B.; Miquel, R.; Bernstein, G. M.; Bonnett, C.; Carnero Rosell, A.; Castander, F. J.; Chang, C.; da Costa, L. N.; Gruen, D.; Gschwend, J.; Hartley, W. G.; Lin, H.; MacCrann, N.; Maia, M. A. G.; Ogando, R. L. C.; Roodman, A.; Sevilla-Noarbe, I.; Troxel, M. A.; Wechsler, R. H.; Asorey, J.; Davis, T. M.; Glazebrook, K.; Hinton, S. R.; Lewis, G.; Lidman, C.; Macaulay, E.; Möller, A.; O'Neill, C. R.; Sommer, N. E.; Uddin, S. A.; Yuan, F.; Zhang, B.; Abbott, T. M. C.; Allam, S.; Annis, J.; Bechtol, K.; Brooks, D.; Burke, D. L.; Carollo, D.; Carrasco Kind, M.; Carretero, J.; Cunha, C. E.; D'Andrea, C. B.; DePoy, D. L.; Desai, S.; Eifler, T. F.; Evrard, A. E.; Flaugher, B.; Fosalba, P.; Frieman, J.; García-Bellido, J.; Gerdes, D. W.; Goldstein, D. A.; Gruendl, R. A.; Gutierrez, G.; Honscheid, K.; Hoormann, J. K.; Jain, B.; James, D. J.; Jarvis, M.; Jeltema, T.; Johnson, M. W. G.; Johnson, M. D.; Krause, E.; Kuehn, K.; Kuhlmann, S.; Kuropatkin, N.; Li, T. S.; Lima, M.; Marshall, J. L.; Melchior, P.; Menanteau, F.; Nichol, R. C.; Nord, B.; Plazas, A. A.; Reil, K.; Rykoff, E. S.; Sako, M.; Sanchez, E.; Scarpine, V.; Schubnell, M.; Sheldon, E.; Smith, M.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Thomas, D.; Tucker, B. E.; Tucker, D. L.; Vikram, V.; Walker, A. R.; Weller, J.; Wester, W.; Wolf, R. C.

2018-06-01

We use numerical simulations to characterize the performance of a clustering-based method to calibrate photometric redshift biases. In particular, we cross-correlate the weak lensing source galaxies from the Dark Energy Survey Year 1 sample with redMaGiC galaxies (luminous red galaxies with secure photometric redshifts) to estimate the redshift distribution of the former sample. The recovered redshift distributions are used to calibrate the photometric redshift bias of standard photo-z methods applied to the same source galaxy sample. We apply the method to two photo-z codes run in our simulated data: Bayesian Photometric Redshift and Directional Neighbourhood Fitting. We characterize the systematic uncertainties of our calibration procedure, and find that these systematic uncertainties dominate our error budget. The dominant systematics are due to our assumption of unevolving bias and clustering across each redshift bin, and to differences between the shapes of the redshift distributions derived by clustering versus photo-zs. The systematic uncertainty in the mean redshift bias of the source galaxy sample is Δz ≲ 0.02, though the precise value depends on the redshift bin under consideration. We discuss possible ways to mitigate the impact of our dominant systematics in future analyses.

An open data repository for steady state analysis of a 100-node electricity distribution network with moderate connection of renewable energy sources.

PubMed

Lazarou, Stavros; Vita, Vasiliki; Ekonomou, Lambros

2018-02-01

The data of this article represent a real electricity distribution network on twenty kilovolts (20 kV) at medium voltage level of the Hellenic electricity distribution system [1]. This network has been chosen as suitable for smart grid analysis. It demonstrates moderate penetration of renewable sources and it has capability in part of time for reverse power flows. It is suitable for studies of load aggregation, storage, demand response. It represents a rural line of fifty-five kilometres (55 km) total length, a typical length for this type. It serves forty-five (45) medium to low voltage transformers and twenty-four (24) connections to photovoltaic plants. The total installed load capacity is twelve mega-volt-ampere (12 MVA), however the maximum observed load is lower. The data are ready to perform load flow simulation on Matpower [2] for the maximum observed load power on the half production for renewables. The simulation results and processed data for creating the source code are also provided on the database available at http://dx.doi.org/10.7910/DVN/1I6MKU.

The use of tetrahedral mesh geometries in Monte Carlo simulation of applicator based brachytherapy dose distributions

NASA Astrophysics Data System (ADS)

Paiva Fonseca, Gabriel; Landry, Guillaume; White, Shane; D'Amours, Michel; Yoriyaz, Hélio; Beaulieu, Luc; Reniers, Brigitte; Verhaegen, Frank

2014-10-01

Accounting for brachytherapy applicator attenuation is part of the recommendations from the recent report of AAPM Task Group 186. To do so, model based dose calculation algorithms require accurate modelling of the applicator geometry. This can be non-trivial in the case of irregularly shaped applicators such as the Fletcher Williamson gynaecological applicator or balloon applicators with possibly irregular shapes employed in accelerated partial breast irradiation (APBI) performed using electronic brachytherapy sources (EBS). While many of these applicators can be modelled using constructive solid geometry (CSG), the latter may be difficult and time-consuming. Alternatively, these complex geometries can be modelled using tessellated geometries such as tetrahedral meshes (mesh geometries (MG)). Recent versions of Monte Carlo (MC) codes Geant4 and MCNP6 allow for the use of MG. The goal of this work was to model a series of applicators relevant to brachytherapy using MG. Applicators designed for 192Ir sources and 50 kV EBS were studied; a shielded vaginal applicator, a shielded Fletcher Williamson applicator and an APBI balloon applicator. All applicators were modelled in Geant4 and MCNP6 using MG and CSG for dose calculations. CSG derived dose distributions were considered as reference and used to validate MG models by comparing dose distribution ratios. In general agreement within 1% for the dose calculations was observed for all applicators between MG and CSG and between codes when considering volumes inside the 25% isodose surface. When compared to CSG, MG required longer computation times by a factor of at least 2 for MC simulations using the same code. MCNP6 calculation times were more than ten times shorter than Geant4 in some cases. In conclusion we presented methods allowing for high fidelity modelling with results equivalent to CSG. To the best of our knowledge MG offers the most accurate representation of an irregular APBI balloon applicator.

HELIOS: A new open-source radiative transfer code

NASA Astrophysics Data System (ADS)

Malik, Matej; Grosheintz, Luc; Lukas Grimm, Simon; Mendonça, João; Kitzmann, Daniel; Heng, Kevin

2015-12-01

I present the new open-source code HELIOS, developed to accurately describe radiative transfer in a wide variety of irradiated atmospheres. We employ a one-dimensional multi-wavelength two-stream approach with scattering. Written in Cuda C++, HELIOS uses the GPU’s potential of massive parallelization and is able to compute the TP-profile of an atmosphere in radiative equilibrium and the subsequent emission spectrum in a few minutes on a single computer (for 60 layers and 1000 wavelength bins).The required molecular opacities are obtained with the recently published code HELIOS-K [1], which calculates the line shapes from an input line list and resamples the numerous line-by-line data into a manageable k-distribution format. Based on simple equilibrium chemistry theory [2] we combine the k-distribution functions of the molecules H2O, CO2, CO & CH4 to generate a k-table, which we then employ in HELIOS.I present our results of the following: (i) Various numerical tests, e.g. isothermal vs. non-isothermal treatment of layers. (ii) Comparison of iteratively determined TP-profiles with their analytical parametric prescriptions [3] and of the corresponding spectra. (iii) Benchmarks of TP-profiles & spectra for various elemental abundances. (iv) Benchmarks of averaged TP-profiles & spectra for the exoplanets GJ1214b, HD189733b & HD209458b. (v) Comparison with secondary eclipse data for HD189733b, XO-1b & Corot-2b.HELIOS is being developed, together with the dynamical core THOR and the chemistry solver VULCAN, in the group of Kevin Heng at the University of Bern as part of the Exoclimes Simulation Platform (ESP) [4], which is an open-source project aimed to provide community tools to model exoplanetary atmospheres.-----------------------------[1] Grimm & Heng 2015, ArXiv, 1503.03806[2] Heng, Lyons & Tsai, Arxiv, 1506.05501Heng & Lyons, ArXiv, 1507.01944[3] e.g. Heng, Mendonca & Lee, 2014, ApJS, 215, 4H[4] exoclime.net

FracPaQ: A MATLAB™ toolbox for the quantification of fracture patterns

NASA Astrophysics Data System (ADS)

Healy, David; Rizzo, Roberto E.; Cornwell, David G.; Farrell, Natalie J. C.; Watkins, Hannah; Timms, Nick E.; Gomez-Rivas, Enrique; Smith, Michael

2017-02-01

The patterns of fractures in deformed rocks are rarely uniform or random. Fracture orientations, sizes, and spatial distributions often exhibit some kind of order. In detail, relationships may exist among the different fracture attributes, e.g. small fractures dominated by one orientation, larger fractures by another. These relationships are important because the mechanical (e.g. strength, anisotropy) and transport (e.g. fluids, heat) properties of rock depend on these fracture attributes and patterns. This paper describes FracPaQ, a new open source, cross-platform toolbox to quantify fracture patterns, including distributions in fracture attributes and their spatial variation. Software has been developed to quantify fracture patterns from 2-D digital images, such as thin section micrographs, geological maps, outcrop or aerial photographs or satellite images. The toolbox comprises a suite of MATLAB™ scripts based on previously published quantitative methods for the analysis of fracture attributes: orientations, lengths, intensity, density and connectivity. An estimate of permeability in 2-D is made using a parallel plate model. The software provides an objective and consistent methodology for quantifying fracture patterns and their variations in 2-D across a wide range of length scales, rock types and tectonic settings. The implemented methods presented are inherently scale independent, and a key task where applicable is analysing and integrating quantitative fracture pattern data from micro-to macro-scales. The toolbox was developed in MATLAB™ and the source code is publicly available on GitHub™ and the Mathworks™ FileExchange. The code runs on any computer with MATLAB installed, including PCs with Microsoft Windows, Apple Macs with Mac OS X, and machines running different flavours of Linux. The application, source code and sample input files are available in open repositories in the hope that other developers and researchers will optimise and extend the functionality for the benefit of the wider community.

MzJava: An open source library for mass spectrometry data processing.

PubMed

Horlacher, Oliver; Nikitin, Frederic; Alocci, Davide; Mariethoz, Julien; Müller, Markus; Lisacek, Frederique

2015-11-03

Mass spectrometry (MS) is a widely used and evolving technique for the high-throughput identification of molecules in biological samples. The need for sharing and reuse of code among bioinformaticians working with MS data prompted the design and implementation of MzJava, an open-source Java Application Programming Interface (API) for MS related data processing. MzJava provides data structures and algorithms for representing and processing mass spectra and their associated biological molecules, such as metabolites, glycans and peptides. MzJava includes functionality to perform mass calculation, peak processing (e.g. centroiding, filtering, transforming), spectrum alignment and clustering, protein digestion, fragmentation of peptides and glycans as well as scoring functions for spectrum-spectrum and peptide/glycan-spectrum matches. For data import and export MzJava implements readers and writers for commonly used data formats. For many classes support for the Hadoop MapReduce (hadoop.apache.org) and Apache Spark (spark.apache.org) frameworks for cluster computing was implemented. The library has been developed applying best practices of software engineering. To ensure that MzJava contains code that is correct and easy to use the library's API was carefully designed and thoroughly tested. MzJava is an open-source project distributed under the AGPL v3.0 licence. MzJava requires Java 1.7 or higher. Binaries, source code and documentation can be downloaded from http://mzjava.expasy.org and https://bitbucket.org/sib-pig/mzjava. This article is part of a Special Issue entitled: Computational Proteomics. Copyright © 2015 Elsevier B.V. All rights reserved.

Dynamical beam manipulation based on 2-bit digitally-controlled coding metasurface.

PubMed

Huang, Cheng; Sun, Bo; Pan, Wenbo; Cui, Jianhua; Wu, Xiaoyu; Luo, Xiangang

2017-02-08

Recently, a concept of digital metamaterials has been proposed to manipulate field distribution through proper spatial mixtures of digital metamaterial bits. Here, we present a design of 2-bit digitally-controlled coding metasurface that can effectively modulate the scattered electromagnetic wave and realize different far-field beams. Each meta-atom of this metasurface integrates two pin diodes, and by tuning their operating states, the metasurface has four phase responses of 0, π/2, π, and 3π/2, corresponding to four basic digital elements "00", "01", "10", and "11", respectively. By designing the coding sequence of the above digital element array, the reflected beam can be arbitrarily controlled. The proposed 2-bit digital metasurface has been demonstrated to possess capability of achieving beam deflection, multi-beam and beam diffusion, and the dynamical switching of these different scattering patterns is completed by a programmable electric source.

Transfer reaction code with nonlocal interactions

DOE PAGES

Titus, L. J.; Ross, A.; Nunes, F. M.

2016-07-14

We present a suite of codes (NLAT for nonlocal adiabatic transfer) to calculate the transfer cross section for single-nucleon transfer reactions, (d,N)(d,N) or (N,d)(N,d), including nonlocal nucleon–target interactions, within the adiabatic distorted wave approximation. For this purpose, we implement an iterative method for solving the second order nonlocal differential equation, for both scattering and bound states. The final observables that can be obtained with NLAT are differential angular distributions for the cross sections of A(d,N)BA(d,N)B or B(N,d)AB(N,d)A. Details on the implementation of the TT-matrix to obtain the final cross sections within the adiabatic distorted wave approximation method are also provided.more » This code is suitable to be applied for deuteron induced reactions in the range of View the MathML sourceEd=10–70MeV, and provides cross sections with 4% accuracy.« less

Dynamical beam manipulation based on 2-bit digitally-controlled coding metasurface

PubMed Central

Huang, Cheng; Sun, Bo; Pan, Wenbo; Cui, Jianhua; Wu, Xiaoyu; Luo, Xiangang

2017-01-01

Recently, a concept of digital metamaterials has been proposed to manipulate field distribution through proper spatial mixtures of digital metamaterial bits. Here, we present a design of 2-bit digitally-controlled coding metasurface that can effectively modulate the scattered electromagnetic wave and realize different far-field beams. Each meta-atom of this metasurface integrates two pin diodes, and by tuning their operating states, the metasurface has four phase responses of 0, π/2, π, and 3π/2, corresponding to four basic digital elements “00”, “01”, “10”, and “11”, respectively. By designing the coding sequence of the above digital element array, the reflected beam can be arbitrarily controlled. The proposed 2-bit digital metasurface has been demonstrated to possess capability of achieving beam deflection, multi-beam and beam diffusion, and the dynamical switching of these different scattering patterns is completed by a programmable electric source. PMID:28176870

DOE Office of Scientific and Technical Information (OSTI.GOV)

O'Malley, Daniel; Vesselinov, Velimir V.

MADSpython (Model analysis and decision support tools in Python) is a code in Python that streamlines the process of using data and models for analysis and decision support using the code MADS. MADS is open-source code developed at LANL and written in C/C++ (MADS; http://mads.lanl.gov; LA-CC-11-035). MADS can work with external models of arbitrary complexity as well as built-in models of flow and transport in porous media. The Python scripts in MADSpython facilitate the generation of input and output file needed by MADS as wells as the external simulators which include FEHM and PFLOTRAN. MADSpython enables a number of data-more » and model-based analyses including model calibration, sensitivity analysis, uncertainty quantification, and decision analysis. MADSpython will be released under GPL V3 license. MADSpython will be distributed as a Git repo at gitlab.com and github.com. MADSpython manual and documentation will be posted at http://madspy.lanl.gov.« less

Review of Hybrid (Deterministic/Monte Carlo) Radiation Transport Methods, Codes, and Applications at Oak Ridge National Laboratory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wagner, John C; Peplow, Douglas E.; Mosher, Scott W

2011-01-01

This paper provides a review of the hybrid (Monte Carlo/deterministic) radiation transport methods and codes used at the Oak Ridge National Laboratory and examples of their application for increasing the efficiency of real-world, fixed-source Monte Carlo analyses. The two principal hybrid methods are (1) Consistent Adjoint Driven Importance Sampling (CADIS) for optimization of a localized detector (tally) region (e.g., flux, dose, or reaction rate at a particular location) and (2) Forward Weighted CADIS (FW-CADIS) for optimizing distributions (e.g., mesh tallies over all or part of the problem space) or multiple localized detector regions (e.g., simultaneous optimization of two or moremore » localized tally regions). The two methods have been implemented and automated in both the MAVRIC sequence of SCALE 6 and ADVANTG, a code that works with the MCNP code. As implemented, the methods utilize the results of approximate, fast-running 3-D discrete ordinates transport calculations (with the Denovo code) to generate consistent space- and energy-dependent source and transport (weight windows) biasing parameters. These methods and codes have been applied to many relevant and challenging problems, including calculations of PWR ex-core thermal detector response, dose rates throughout an entire PWR facility, site boundary dose from arrays of commercial spent fuel storage casks, radiation fields for criticality accident alarm system placement, and detector response for special nuclear material detection scenarios and nuclear well-logging tools. Substantial computational speed-ups, generally O(102-4), have been realized for all applications to date. This paper provides a brief review of the methods, their implementation, results of their application, and current development activities, as well as a considerable list of references for readers seeking more information about the methods and/or their applications.« less

Astronomy education and the Astrophysics Source Code Library

NASA Astrophysics Data System (ADS)

Allen, Alice; Nemiroff, Robert J.

2016-01-01

The Astrophysics Source Code Library (ASCL) is an online registry of source codes used in refereed astrophysics research. It currently lists nearly 1,200 codes and covers all aspects of computational astrophysics. How can this resource be of use to educators and to the graduate students they mentor? The ASCL serves as a discovery tool for codes that can be used for one's own research. Graduate students can also investigate existing codes to see how common astronomical problems are approached numerically in practice, and use these codes as benchmarks for their own solutions to these problems. Further, they can deepen their knowledge of software practices and techniques through examination of others' codes.

Automatic Parallelization of Numerical Python Applications using the Global Arrays Toolkit

DOE Office of Scientific and Technical Information (OSTI.GOV)

Daily, Jeffrey A.; Lewis, Robert R.

2011-11-30

Global Arrays is a software system from Pacific Northwest National Laboratory that enables an efficient, portable, and parallel shared-memory programming interface to manipulate distributed dense arrays. The NumPy module is the de facto standard for numerical calculation in the Python programming language, a language whose use is growing rapidly in the scientific and engineering communities. NumPy provides a powerful N-dimensional array class as well as other scientific computing capabilities. However, like the majority of the core Python modules, NumPy is inherently serial. Using a combination of Global Arrays and NumPy, we have reimplemented NumPy as a distributed drop-in replacement calledmore » Global Arrays in NumPy (GAiN). Serial NumPy applications can become parallel, scalable GAiN applications with only minor source code changes. Scalability studies of several different GAiN applications will be presented showing the utility of developing serial NumPy codes which can later run on more capable clusters or supercomputers.« less

Spatially-Dependent Modelling of Pulsar Wind Nebula G0.9+0.1

NASA Astrophysics Data System (ADS)

van Rensburg, C.; Krüger, P. P.; Venter, C.

2018-03-01

We present results from a leptonic emission code that models the spectral energy distribution of a pulsar wind nebula by solving a Fokker-Planck-type transport equation and calculating inverse Compton and synchrotron emissivities. We have created this time-dependent, multi-zone model to investigate changes in the particle spectrum as they traverse the pulsar wind nebula, by considering a time and spatially-dependent B-field, spatially-dependent bulk particle speed implying convection and adiabatic losses, diffusion, as well as radiative losses. Our code predicts the radiation spectrum at different positions in the nebula, yielding the surface brightness versus radius and the nebular size as function of energy. We compare our new model against more basic models using the observed spectrum of pulsar wind nebula G0.9+0.1, incorporating data from H.E.S.S. as well as radio and X-ray experiments. We show that simultaneously fitting the spectral energy distribution and the energy-dependent source size leads to more stringent constraints on several model parameters.

Spatially dependent modelling of pulsar wind nebula G0.9+0.1

NASA Astrophysics Data System (ADS)

van Rensburg, C.; Krüger, P. P.; Venter, C.

2018-07-01

We present results from a leptonic emission code that models the spectral energy distribution of a pulsar wind nebula by solving a Fokker-Planck-type transport equation and calculating inverse Compton and synchrotron emissivities. We have created this time-dependent, multizone model to investigate changes in the particle spectrum as they traverse the pulsar wind nebula, by considering a time and spatially dependent B-field, spatially dependent bulk particle speed implying convection and adiabatic losses, diffusion, as well as radiative losses. Our code predicts the radiation spectrum at different positions in the nebula, yielding the surface brightness versus radius and the nebular size as function of energy. We compare our new model against more basic models using the observed spectrum of pulsar wind nebula G0.9+0.1, incorporating data from H.E.S.S. as well as radio and X-ray experiments. We show that simultaneously fitting the spectral energy distribution and the energy-dependent source size leads to more stringent constraints on several model parameters.

SU-F-19A-05: Experimental and Monte Carlo Characterization of the 1 Cm CivaString 103Pd Brachytherapy Source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reed, J; Micka, J; Culberson, W

Purpose: To determine the in-air azimuthal anisotropy and in-water dose distribution for the 1 cm length of the CivaString {sup 103}Pd brachytherapy source through measurements and Monte Carlo (MC) simulations. American Association of Physicists in Medicine Task Group No. 43 (TG-43) dosimetry parameters were also determined for this source. Methods: The in-air azimuthal anisotropy of the source was measured with a NaI scintillation detector and simulated with the MCNP5 radiation transport code. Measured and simulated results were normalized to their respective mean values and compared. The TG-43 dose-rate constant, line-source radial dose function, and 2D anisotropy function for this sourcemore » were determined from LiF:Mg,Ti thermoluminescent dosimeter (TLD) measurements and MC simulations. The impact of {sup 103}Pd well-loading variability on the in-water dose distribution was investigated using MC simulations by comparing the dose distribution for a source model with four wells of equal strength to that for a source model with strengths increased by 1% for two of the four wells. Results: NaI scintillation detector measurements and MC simulations of the in-air azimuthal anisotropy showed that ≥95% of the normalized data were within 1.2% of the mean value. TLD measurements and MC simulations of the TG-43 dose-rate constant, line-source radial dose function, and 2D anisotropy function agreed to within the experimental TLD uncertainties (k=2). MC simulations showed that a 1% variability in {sup 103}Pd well-loading resulted in changes of <0.1%, <0.1%, and <0.3% in the TG-43 dose-rate constant, radial dose distribution, and polar dose distribution, respectively. Conclusion: The CivaString source has a high degree of azimuthal symmetry as indicated by the NaI scintillation detector measurements and MC simulations of the in-air azimuthal anisotropy. TG-43 dosimetry parameters for this source were determined from TLD measurements and MC simulations. {sup 103}Pd well-loading variability results in minimal variations in the in-water dose distribution according to MC simulations. This work was partially supported by CivaTech Oncology, Inc. through an educational grant for Joshua Reed, John Micka, Wesley Culberson, and Larry DeWerd and through research support for Mark Rivard.« less

Computational mechanics analysis tools for parallel-vector supercomputers

NASA Technical Reports Server (NTRS)

Storaasli, O. O.; Nguyen, D. T.; Baddourah, M. A.; Qin, J.

1993-01-01

Computational algorithms for structural analysis on parallel-vector supercomputers are reviewed. These parallel algorithms, developed by the authors, are for the assembly of structural equations, 'out-of-core' strategies for linear equation solution, massively distributed-memory equation solution, unsymmetric equation solution, general eigen-solution, geometrically nonlinear finite element analysis, design sensitivity analysis for structural dynamics, optimization algorithm and domain decomposition. The source code for many of these algorithms is available from NASA Langley.

Database Entity Persistence with Hibernate for the Network Connectivity Analysis Model

DTIC Science & Technology

2014-04-01

time savings in the Java coding development process. Appendices A and B describe address setup procedures for installing the MySQL database...development environment is required: • The open source MySQL Database Management System (DBMS) from Oracle, which is a Java Database Connectivity (JDBC...compliant DBMS • MySQL JDBC Driver library that comes as a plug-in with the Netbeans distribution • The latest Java Development Kit with the latest

Self-Cohering Airborne Distributed Array

DTIC Science & Technology

1988-06-01

F19628-84- C -0080 ft. ADDRESS (City, State, and ZIP Code) 10. SOURCE OF FUNDING NUMBERS PROGRAM PROJECT JTASK JWORK UNIT Hanscom APE MA 01731-5000...algorithms under consideration (including the newly developed algorithms). The algorithms are classified both according to the type c -f processing and...4.1 RADIO CAMERA DATA FORMAT AND PROCEDURES (FROM C -23) The range trace delivered by each antenna element is stonred as a rc’w of coimplex number-s

Data processing with microcode designed with source coding

DOEpatents

McCoy, James A; Morrison, Steven E

2013-05-07

Programming for a data processor to execute a data processing application is provided using microcode source code. The microcode source code is assembled to produce microcode that includes digital microcode instructions with which to signal the data processor to execute the data processing application.

MIST: An Open Source Environmental Modelling Programming Language Incorporating Easy to Use Data Parallelism.

NASA Astrophysics Data System (ADS)

Bellerby, Tim

2014-05-01

Model Integration System (MIST) is open-source environmental modelling programming language that directly incorporates data parallelism. The language is designed to enable straightforward programming structures, such as nested loops and conditional statements to be directly translated into sequences of whole-array (or more generally whole data-structure) operations. MIST thus enables the programmer to use well-understood constructs, directly relating to the mathematical structure of the model, without having to explicitly vectorize code or worry about details of parallelization. A range of common modelling operations are supported by dedicated language structures operating on cell neighbourhoods rather than individual cells (e.g.: the 3x3 local neighbourhood needed to implement an averaging image filter can be simply accessed from within a simple loop traversing all image pixels). This facility hides details of inter-process communication behind more mathematically relevant descriptions of model dynamics. The MIST automatic vectorization/parallelization process serves both to distribute work among available nodes and separately to control storage requirements for intermediate expressions - enabling operations on very large domains for which memory availability may be an issue. MIST is designed to facilitate efficient interpreter based implementations. A prototype open source interpreter is available, coded in standard FORTRAN 95, with tools to rapidly integrate existing FORTRAN 77 or 95 code libraries. The language is formally specified and thus not limited to FORTRAN implementation or to an interpreter-based approach. A MIST to FORTRAN compiler is under development and volunteers are sought to create an ANSI-C implementation. Parallel processing is currently implemented using OpenMP. However, parallelization code is fully modularised and could be replaced with implementations using other libraries. GPU implementation is potentially possible.

Phase II evaluation of clinical coding schemes: completeness, taxonomy, mapping, definitions, and clarity. CPRI Work Group on Codes and Structures.

PubMed

Campbell, J R; Carpenter, P; Sneiderman, C; Cohn, S; Chute, C G; Warren, J

1997-01-01

To compare three potential sources of controlled clinical terminology (READ codes version 3.1, SNOMED International, and Unified Medical Language System (UMLS) version 1.6) relative to attributes of completeness, clinical taxonomy, administrative mapping, term definitions and clarity (duplicate coding rate). The authors assembled 1929 source concept records from a variety of clinical information taken from four medical centers across the United States. The source data included medical as well as ample nursing terminology. The source records were coded in each scheme by an investigator and checked by the coding scheme owner. The codings were then scored by an independent panel of clinicians for acceptability. Codes were checked for definitions provided with the scheme. Codes for a random sample of source records were analyzed by an investigator for "parent" and "child" codes within the scheme. Parent and child pairs were scored by an independent panel of medical informatics specialists for clinical acceptability. Administrative and billing code mapping from the published scheme were reviewed for all coded records and analyzed by independent reviewers for accuracy. The investigator for each scheme exhaustively searched a sample of coded records for duplications. SNOMED was judged to be significantly more complete in coding the source material than the other schemes (SNOMED* 70%; READ 57%; UMLS 50%; *p < .00001). SNOMED also had a richer clinical taxonomy judged by the number of acceptable first-degree relatives per coded concept (SNOMED* 4.56, UMLS 3.17; READ 2.14, *p < .005). Only the UMLS provided any definitions; these were found for 49% of records which had a coding assignment. READ and UMLS had better administrative mappings (composite score: READ* 40.6%; UMLS* 36.1%; SNOMED 20.7%, *p < .00001), and SNOMED had substantially more duplications of coding assignments (duplication rate: READ 0%; UMLS 4.2%; SNOMED* 13.9%, *p < .004) associated with a loss of clarity. No major terminology source can lay claim to being the ideal resource for a computer-based patient record. However, based upon this analysis of releases for April 1995, SNOMED International is considerably more complete, has a compositional nature and a richer taxonomy. Is suffers from less clarity, resulting from a lack of syntax and evolutionary changes in its coding scheme. READ has greater clarity and better mapping to administrative schemes (ICD-10 and OPCS-4), is rapidly changing and is less complete. UMLS is a rich lexical resource, with mappings to many source vocabularies. It provides definitions for many of its terms. However, due to the varying granularities and purposes of its source schemes, it has limitations for representation of clinical concepts within a computer-based patient record.

Update of GRASP/Ada reverse engineering tools for Ada

NASA Technical Reports Server (NTRS)

Cross, James H., II

1993-01-01

The GRASP/Ada project (Graphical Representations of Algorithms, Structures, and Processes for Ada) successfully created and prototyped a new algorithmic level graphical representation for Ada software, the Control Structure Diagram (CSD). The primary impetus for creation of the CSD was to improve the comprehension efficiency of Ada software and, as a result, improve reliability and reduce costs. The emphasis was on the automatic generation of the CSD from Ada PDL or source code to support reverse engineering and maintenance. The CSD has the potential to replace traditional pretty printed Ada source code. In Phase 1 of the GRASP/Ada project, the CSD graphical constructs were created and applied manually to several small Ada programs. A prototype CSD generator (Version 1) was designed and implemented using FLEX and BISON running under VMS on a VAX 11-780. In Phase 2, the prototype was improved and ported to the Sun 4 platform under UNIX. A user interface was designed and partially implemented using the HP widget toolkit and the X Windows System. In Phase 3, the user interface was extensively reworked using the Athena widget toolkit and X Windows. The prototype was applied successfully to numerous Ada programs ranging in size from several hundred to several thousand lines of source code. Following Phase 3,e two update phases were completed. Update'92 focused on the initial analysis of evaluation data collected from software engineering students at Auburn University and the addition of significant enhancements to the user interface. Update'93 (the current update) focused on the statistical analysis of the data collected in the previous update and preparation of Version 3.4 of the prototype for limited distribution to facilitate further evaluation. The current prototype provides the capability for the user to generate CSD's from Ada PDL or source code in a reverse engineering as well as forward engineering mode with a level of flexibility suitable for practical application. An overview of the GRASP/Ada project with an emphasis on the current update is provided.

PubMed

Trinker, Horst

2011-10-28

We study the distribution of triples of codewords of codes and ordered codes. Schrijver [A. Schrijver, New code upper bounds from the Terwilliger algebra and semidefinite programming, IEEE Trans. Inform. Theory 51 (8) (2005) 2859-2866] used the triple distribution of a code to establish a bound on the number of codewords based on semidefinite programming. In the first part of this work, we generalize this approach for ordered codes. In the second part, we consider linear codes and linear ordered codes and present a MacWilliams-type identity for the triple distribution of their dual code. Based on the non-negativity of this linear transform, we establish a linear programming bound and conclude with a table of parameters for which this bound yields better results than the standard linear programming bound.

MDSplus quality improvement project

DOE PAGES

Fredian, Thomas W.; Stillerman, Joshua; Manduchi, Gabriele; ...

2016-05-31

MDSplus is a data acquisition and analysis system used worldwide predominantly in the fusion research community. Development began 29 years ago on the OpenVMS operating system. Since that time there have been many new features added and the code has been ported to many different operating systems. There have been contributions to the MDSplus development from the fusion community in the way of feature suggestions, feature implementations, documentation and porting to different operating systems. The bulk of the development and support of MDSplus, however, has been provided by a relatively small core developer group of three or four members. Givenmore » the size of the development team and the large number of users much more effort was focused on providing new features for the community than on keeping the underlying code and documentation up to date with the evolving software development standards. To ensure that MDSplus will continue to provide the needs of the community in the future, the MDSplus development team along with other members of the MDSplus user community has commenced on a major quality improvement project. The planned improvements include changes to software build scripts to better use GNU Autoconf and Automake tools, refactoring many of the source code modules using new language features available in modern compilers, using GNU MinGW-w64 to create MS Windows distributions, migrating to a more modern source code management system, improvement of source documentation as well as improvements to the www.mdsplus.org web site documentation and layout, and the addition of more comprehensive test suites to apply to MDSplus code builds prior to releasing installation kits to the community. This paper should lead to a much more robust product and establish a framework to maintain stability as more enhancements and features are added. Finally, this paper will describe these efforts that are either in progress or planned for the near future.« less

Distributed computing environments for future space control systems

NASA Technical Reports Server (NTRS)

Viallefont, Pierre

1993-01-01

The aim of this paper is to present the results of a CNES research project on distributed computing systems. The purpose of this research was to study the impact of the use of new computer technologies in the design and development of future space applications. The first part of this study was a state-of-the-art review of distributed computing systems. One of the interesting ideas arising from this review is the concept of a 'virtual computer' allowing the distributed hardware architecture to be hidden from a software application. The 'virtual computer' can improve system performance by adapting the best architecture (addition of computers) to the software application without having to modify its source code. This concept can also decrease the cost and obsolescence of the hardware architecture. In order to verify the feasibility of the 'virtual computer' concept, a prototype representative of a distributed space application is being developed independently of the hardware architecture.

The Particle Accelerator Simulation Code PyORBIT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gorlov, Timofey V; Holmes, Jeffrey A; Cousineau, Sarah M

2015-01-01

The particle accelerator simulation code PyORBIT is presented. The structure, implementation, history, parallel and simulation capabilities, and future development of the code are discussed. The PyORBIT code is a new implementation and extension of algorithms of the original ORBIT code that was developed for the Spallation Neutron Source accelerator at the Oak Ridge National Laboratory. The PyORBIT code has a two level structure. The upper level uses the Python programming language to control the flow of intensive calculations performed by the lower level code implemented in the C++ language. The parallel capabilities are based on MPI communications. The PyORBIT ismore » an open source code accessible to the public through the Google Open Source Projects Hosting service.« less

BioNetFit: a fitting tool compatible with BioNetGen, NFsim and distributed computing environments.

PubMed

Thomas, Brandon R; Chylek, Lily A; Colvin, Joshua; Sirimulla, Suman; Clayton, Andrew H A; Hlavacek, William S; Posner, Richard G

2016-03-01

Rule-based models are analyzed with specialized simulators, such as those provided by the BioNetGen and NFsim open-source software packages. Here, we present BioNetFit, a general-purpose fitting tool that is compatible with BioNetGen and NFsim. BioNetFit is designed to take advantage of distributed computing resources. This feature facilitates fitting (i.e. optimization of parameter values for consistency with data) when simulations are computationally expensive. BioNetFit can be used on stand-alone Mac, Windows/Cygwin, and Linux platforms and on Linux-based clusters running SLURM, Torque/PBS, or SGE. The BioNetFit source code (Perl) is freely available (http://bionetfit.nau.edu). Supplementary data are available at Bioinformatics online. bionetgen.help@gmail.com. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

LSST communications middleware implementation

NASA Astrophysics Data System (ADS)

Mills, Dave; Schumacher, German; Lotz, Paul

2016-07-01

The LSST communications middleware is based on a set of software abstractions; which provide standard interfaces for common communications services. The observatory requires communication between diverse subsystems, implemented by different contractors, and comprehensive archiving of subsystem status data. The Service Abstraction Layer (SAL) is implemented using open source packages that implement open standards of DDS (Data Distribution Service1) for data communication, and SQL (Standard Query Language) for database access. For every subsystem, abstractions for each of the Telemetry datastreams, along with Command/Response and Events, have been agreed with the appropriate component vendor (such as Dome, TMA, Hexapod), and captured in ICD's (Interface Control Documents).The OpenSplice (Prismtech) Community Edition of DDS provides an LGPL licensed distribution which may be freely redistributed. The availability of the full source code provides assurances that the project will be able to maintain it over the full 10 year survey, independent of the fortunes of the original providers.

Positron Scanner for Locating Brain Tumors

DOE R&D Accomplishments Database

Rankowitz, S.; Robertson, J. S.; Higinbotham, W. A.; Rosenblum, M. J.

1962-03-01

A system is described that makes use of positron emitting isotopes for locating brain tumors. This system inherently provides more information about the distribution of radioactivity in the head in less time than existing scanners which use one or two detectors. A stationary circular array of 32 scintillation detectors scans a horizontal layer of the head from many directions simultaneously. The data, consisting of the number of counts in all possible coincidence pairs, are coded and stored in the memory of a Two-Dimensional Pulse-Height Analyzer. A unique method of displaying and interpreting the data is described that enables rapid approximate analysis of complex source distribution patterns. (auth)

Thermal and flow analysis of the Fluor Daniel, Inc., Nuclear Material Storage Facility renovation design (initial 30% effort of Title 1)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Steinke, R.G.; Mueller, C.; Knight, T.D.

1998-03-01

The computational fluid dynamics code CFX4.2 was used to evaluate steady-state thermal-hydraulic conditions in the Fluor Daniel, Inc., Nuclear Material Storage Facility renovation design (initial 30% of Title 1). Thirteen facility cases were evaluated with varying temperature dependence, drywell-array heat-source magnitude and distribution, location of the inlet tower, and no-flow curtains in the drywell-array vault. Four cases of a detailed model of the inlet-tower top fixture were evaluated to show the effect of the canopy-cruciform fixture design on the air pressure and flow distributions.

Colour cyclic code for Brillouin distributed sensors

NASA Astrophysics Data System (ADS)

Le Floch, Sébastien; Sauser, Florian; Llera, Miguel; Rochat, Etienne

2015-09-01

For the first time, a colour cyclic coding (CCC) is theoretically and experimentally demonstrated for Brillouin optical time-domain analysis (BOTDA) distributed sensors. Compared to traditional intensity-modulated cyclic codes, the code presents an additional gain of √2 while keeping the same number of sequences as for a colour coding. A comparison with a standard BOTDA sensor is realized and validates the theoretical coding gain.

Impacts of DNAPL Source Treatment: Experimental and Modeling Assessment of the Benefits of Partial DNAPL Source Removal

DTIC Science & Technology

2009-09-01

nuclear industry for conducting performance assessment calculations. The analytical FORTRAN code for the DNAPL source function, REMChlor, was...project. The first was to apply existing deterministic codes , such as T2VOC and UTCHEM, to the DNAPL source zone to simulate the remediation processes...but describe the spatial variability of source zones unlike one-dimensional flow and transport codes that assume homogeneity. The Lagrangian models

Visual communications with side information via distributed printing channels: extended multimedia and security perspectives

NASA Astrophysics Data System (ADS)

Voloshynovskiy, Sviatoslav V.; Koval, Oleksiy; Deguillaume, Frederic; Pun, Thierry

2004-06-01

In this paper we address visual communications via printing channels from an information-theoretic point of view as communications with side information. The solution to this problem addresses important aspects of multimedia data processing, security and management, since printed documents are still the most common form of visual information representation. Two practical approaches to side information communications for printed documents are analyzed in the paper. The first approach represents a layered joint source-channel coding for printed documents. This approach is based on a self-embedding concept where information is first encoded assuming a Wyner-Ziv set-up and then embedded into the original data using a Gel'fand-Pinsker construction and taking into account properties of printing channels. The second approach is based on Wyner-Ziv and Berger-Flynn-Gray set-ups and assumes two separated communications channels where an appropriate distributed coding should be elaborated. The first printing channel is considered to be a direct visual channel for images ("analog" channel with degradations). The second "digital channel" with constrained capacity is considered to be an appropriate auxiliary channel. We demonstrate both theoretically and practically how one can benefit from this sort of "distributed paper communications".

Global modeling of thermospheric airglow in the far ultraviolet

NASA Astrophysics Data System (ADS)

Solomon, Stanley C.

2017-07-01

The Global Airglow (GLOW) model has been updated and extended to calculate thermospheric emissions in the far ultraviolet, including sources from daytime photoelectron-driven processes, nighttime recombination radiation, and auroral excitation. It can be run using inputs from empirical models of the neutral atmosphere and ionosphere or from numerical general circulation models of the coupled ionosphere-thermosphere system. It uses a solar flux module, photoelectron generation routine, and the Nagy-Banks two-stream electron transport algorithm to simultaneously handle energetic electron distributions from photon and auroral electron sources. It contains an ion-neutral chemistry module that calculates excited and ionized species densities and the resulting airglow volume emission rates. This paper describes the inputs, algorithms, and code structure of the model and demonstrates example outputs for daytime and auroral cases. Simulations of far ultraviolet emissions by the atomic oxygen doublet at 135.6 nm and the molecular nitrogen Lyman-Birge-Hopfield bands, as viewed from geostationary orbit, are shown, and model calculations are compared to limb-scan observations by the Global Ultraviolet Imager on the TIMED satellite. The GLOW model code is provided to the community through an open-source academic research license.

Directional interstitial brachytherapy from simulation to application

NASA Astrophysics Data System (ADS)

Lin, Liyong

Organs at risk (OAR) are sometimes adjacent to or embedded in or overlap with the clinical target volume (CTV) to be treated. The purpose of this PhD study is to develop directionally low energy gamma-emitting interstitial brachytherapy sources. These sources can be applied between OAR to selectively reduce hot spots in the OARs and normal tissues. The reduction of dose over undesired regions can expand patient eligibility or reduce toxicities for the treatment by conventional interstitial brachytherapy. This study covers the development of a directional source from design optimization to construction of the first prototype source. The Monte Carlo code MCNP was used to simulate the radiation transport for the designs of directional sources. We have made a special construction kit to assemble radioactive and gold-shield components precisely into D-shaped titanium containers of the first directional source. Directional sources have a similar dose distribution as conventional sources on the treated side but greatly reduced dose on the shielded side, with a sharp dose gradient between them. A three-dimensional dose deposition kernel for the 125I directional source has been calculated. Treatment plans can use both directional and conventional 125I sources at the same source strength for low-dose-rate (LDR) implants to optimize the dose distributions. For prostate tumors, directional 125I LDR brachytherapy can potentially reduce genitourinary and gastrointestinal toxicities and improve potency preservation for low risk patients. The combination of better dose distribution of directional implants and better therapeutic ratio between tumor response and late reactions enables a novel temporary LDR treatment, as opposed to permanent or high-dose-rate (HDR) brachytherapy for the intermediate risk T2b and high risk T2c tumors. Supplemental external-beam treatments can be shortened with a better brachytherapy boost for T3 tumors. In conclusion, we have successfully finished the design optimization and construction of the first prototype directional source. Potential clinical applications and potential benefits of directional sources have been shown for prostate and breast tumors.

Phase II Evaluation of Clinical Coding Schemes

PubMed Central

Campbell, James R.; Carpenter, Paul; Sneiderman, Charles; Cohn, Simon; Chute, Christopher G.; Warren, Judith

1997-01-01

Abstract Objective: To compare three potential sources of controlled clinical terminology (READ codes version 3.1, SNOMED International, and Unified Medical Language System (UMLS) version 1.6) relative to attributes of completeness, clinical taxonomy, administrative mapping, term definitions and clarity (duplicate coding rate). Methods: The authors assembled 1929 source concept records from a variety of clinical information taken from four medical centers across the United States. The source data included medical as well as ample nursing terminology. The source records were coded in each scheme by an investigator and checked by the coding scheme owner. The codings were then scored by an independent panel of clinicians for acceptability. Codes were checked for definitions provided with the scheme. Codes for a random sample of source records were analyzed by an investigator for “parent” and “child” codes within the scheme. Parent and child pairs were scored by an independent panel of medical informatics specialists for clinical acceptability. Administrative and billing code mapping from the published scheme were reviewed for all coded records and analyzed by independent reviewers for accuracy. The investigator for each scheme exhaustively searched a sample of coded records for duplications. Results: SNOMED was judged to be significantly more complete in coding the source material than the other schemes (SNOMED* 70%; READ 57%; UMLS 50%; *p <.00001). SNOMED also had a richer clinical taxonomy judged by the number of acceptable first-degree relatives per coded concept (SNOMED* 4.56; UMLS 3.17; READ 2.14, *p <.005). Only the UMLS provided any definitions; these were found for 49% of records which had a coding assignment. READ and UMLS had better administrative mappings (composite score: READ* 40.6%; UMLS* 36.1%; SNOMED 20.7%, *p <. 00001), and SNOMED had substantially more duplications of coding assignments (duplication rate: READ 0%; UMLS 4.2%; SNOMED* 13.9%, *p <. 004) associated with a loss of clarity. Conclusion: No major terminology source can lay claim to being the ideal resource for a computer-based patient record. However, based upon this analysis of releases for April 1995, SNOMED International is considerably more complete, has a compositional nature and a richer taxonomy. It suffers from less clarity, resulting from a lack of syntax and evolutionary changes in its coding scheme. READ has greater clarity and better mapping to administrative schemes (ICD-10 and OPCS-4), is rapidly changing and is less complete. UMLS is a rich lexical resource, with mappings to many source vocabularies. It provides definitions for many of its terms. However, due to the varying granularities and purposes of its source schemes, it has limitations for representation of clinical concepts within a computer-based patient record. PMID:9147343

Modeling and simulation of RF photoinjectors for coherent light sources

NASA Astrophysics Data System (ADS)

Chen, Y.; Krasilnikov, M.; Stephan, F.; Gjonaj, E.; Weiland, T.; Dohlus, M.

2018-05-01

We propose a three-dimensional fully electromagnetic numerical approach for the simulation of RF photoinjectors for coherent light sources. The basic idea consists in incorporating a self-consistent photoemission model within a particle tracking code. The generation of electron beams in the injector is determined by the quantum efficiency (QE) of the cathode, the intensity profile of the driving laser as well as by the accelerating field and magnetic focusing conditions in the gun. The total charge emitted during an emission cycle can be limited by the space charge field at the cathode. Furthermore, the time and space dependent electromagnetic field at the cathode may induce a transient modulation of the QE due to surface barrier reduction of the emitting layer. In our modeling approach, all these effects are taken into account. The beam particles are generated dynamically according to the local QE of the cathode and the time dependent laser intensity profile. For the beam dynamics, a tracking code based on the Lienard-Wiechert retarded field formalism is employed. This code provides the single particle trajectories as well as the transient space charge field distribution at the cathode. As an application, the PITZ injector is considered. Extensive electron bunch emission simulations are carried out for different operation conditions of the injector, in the source limited as well as in the space charge limited emission regime. In both cases, fairly good agreement between measurements and simulations is obtained.

EO/IR scene generation open source initiative for real-time hardware-in-the-loop and all-digital simulation

NASA Astrophysics Data System (ADS)

Morris, Joseph W.; Lowry, Mac; Boren, Brett; Towers, James B.; Trimble, Darian E.; Bunfield, Dennis H.

2011-06-01

The US Army Aviation and Missile Research, Development and Engineering Center (AMRDEC) and the Redstone Test Center (RTC) has formed the Scene Generation Development Center (SGDC) to support the Department of Defense (DoD) open source EO/IR Scene Generation initiative for real-time hardware-in-the-loop and all-digital simulation. Various branches of the DoD have invested significant resources in the development of advanced scene and target signature generation codes. The SGDC goal is to maintain unlimited government rights and controlled access to government open source scene generation and signature codes. In addition, the SGDC provides development support to a multi-service community of test and evaluation (T&E) users, developers, and integrators in a collaborative environment. The SGDC has leveraged the DoD Defense Information Systems Agency (DISA) ProjectForge (https://Project.Forge.mil) which provides a collaborative development and distribution environment for the DoD community. The SGDC will develop and maintain several codes for tactical and strategic simulation, such as the Joint Signature Image Generator (JSIG), the Multi-spectral Advanced Volumetric Real-time Imaging Compositor (MAVRIC), and Office of the Secretary of Defense (OSD) Test and Evaluation Science and Technology (T&E/S&T) thermal modeling and atmospherics packages, such as EOView, CHARM, and STAR. Other utility packages included are the ContinuumCore for real-time messaging and data management and IGStudio for run-time visualization and scenario generation.

PDB file parser and structure class implemented in Python.

PubMed

Hamelryck, Thomas; Manderick, Bernard

2003-11-22

The biopython project provides a set of bioinformatics tools implemented in Python. Recently, biopython was extended with a set of modules that deal with macromolecular structure. Biopython now contains a parser for PDB files that makes the atomic information available in an easy-to-use but powerful data structure. The parser and data structure deal with features that are often left out or handled inadequately by other packages, e.g. atom and residue disorder (if point mutants are present in the crystal), anisotropic B factors, multiple models and insertion codes. In addition, the parser performs some sanity checking to detect obvious errors. The Biopython distribution (including source code and documentation) is freely available (under the Biopython license) from http://www.biopython.org

Doclet To Synthesize UML

NASA Technical Reports Server (NTRS)

Barry, Matthew R.; Osborne, Richard N.

2005-01-01

The RoseDoclet computer program extends the capability of Java doclet software to automatically synthesize Unified Modeling Language (UML) content from Java language source code. [Doclets are Java-language programs that use the doclet application programming interface (API) to specify the content and format of the output of Javadoc. Javadoc is a program, originally designed to generate API documentation from Java source code, now also useful as an extensible engine for processing Java source code.] RoseDoclet takes advantage of Javadoc comments and tags already in the source code to produce a UML model of that code. RoseDoclet applies the doclet API to create a doclet passed to Javadoc. The Javadoc engine applies the doclet to the source code, emitting the output format specified by the doclet. RoseDoclet emits a Rose model file and populates it with fully documented packages, classes, methods, variables, and class diagrams identified in the source code. The way in which UML models are generated can be controlled by use of new Javadoc comment tags that RoseDoclet provides. The advantage of using RoseDoclet is that Javadoc documentation becomes leveraged for two purposes: documenting the as-built API and keeping the design documentation up to date.

shiftNMFk 1.1: Robust Nonnegative matrix factorization with kmeans clustering and signal shift, for allocation of unknown physical sources, toy version for open sourcing with publications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alexandrov, Boian S.; Lliev, Filip L.; Stanev, Valentin G.

This code is a toy (short) version of CODE-2016-83. From a general perspective, the code represents an unsupervised adaptive machine learning algorithm that allows efficient and high performance de-mixing and feature extraction of a multitude of non-negative signals mixed and recorded by a network of uncorrelated sensor arrays. The code identifies the number of the mixed original signals and their locations. Further, the code also allows deciphering of signals that have been delayed in regards to the mixing process in each sensor. This code is high customizable and it can be efficiently used for a fast macro-analyses of data. Themore » code is applicable to a plethora of distinct problems: chemical decomposition, pressure transient decomposition, unknown sources/signal allocation, EM signal decomposition. An additional procedure for allocation of the unknown sources is incorporated in the code.« less

Ground-motion modeling of the 1906 San Francisco earthquake, part I: Validation using the 1989 Loma Prieta earthquake

USGS Publications Warehouse

Aagaard, Brad T.; Brocher, T.M.; Dolenc, D.; Dreger, D.; Graves, R.W.; Harmsen, S.; Hartzell, S.; Larsen, S.; Zoback, M.L.

2008-01-01

We compute ground motions for the Beroza (1991) and Wald et al. (1991) source models of the 1989 magnitude 6.9 Loma Prieta earthquake using four different wave-propagation codes and recently developed 3D geologic and seismic velocity models. In preparation for modeling the 1906 San Francisco earthquake, we use this well-recorded earthquake to characterize how well our ground-motion simulations reproduce the observed shaking intensities and amplitude and durations of recorded motions throughout the San Francisco Bay Area. All of the simulations generate ground motions consistent with the large-scale spatial variations in shaking associated with rupture directivity and the geologic structure. We attribute the small variations among the synthetics to the minimum shear-wave speed permitted in the simulations and how they accommodate topography. Our long-period simulations, on average, under predict shaking intensities by about one-half modified Mercalli intensity (MMI) units (25%-35% in peak velocity), while our broadband simulations, on average, under predict the shaking intensities by one-fourth MMI units (16% in peak velocity). Discrepancies with observations arise due to errors in the source models and geologic structure. The consistency in the synthetic waveforms across the wave-propagation codes for a given source model suggests the uncertainty in the source parameters tends to exceed the uncertainty in the seismic velocity structure. In agreement with earlier studies, we find that a source model with slip more evenly distributed northwest and southeast of the hypocenter would be preferable to both the Beroza and Wald source models. Although the new 3D seismic velocity model improves upon previous velocity models, we identify two areas needing improvement. Nevertheless, we find that the seismic velocity model and the wave-propagation codes are suitable for modeling the 1906 earthquake and scenario events in the San Francisco Bay Area.

scarlet: Source separation in multi-band images by Constrained Matrix Factorization

NASA Astrophysics Data System (ADS)

Melchior, Peter; Moolekamp, Fred; Jerdee, Maximilian; Armstrong, Robert; Sun, Ai-Lei; Bosch, James; Lupton, Robert

2018-03-01

SCARLET performs source separation (aka "deblending") on multi-band images. It is geared towards optical astronomy, where scenes are composed of stars and galaxies, but it is straightforward to apply it to other imaging data. Separation is achieved through a constrained matrix factorization, which models each source with a Spectral Energy Distribution (SED) and a non-parametric morphology, or multiple such components per source. The code performs forced photometry (with PSF matching if needed) using an optimal weight function given by the signal-to-noise weighted morphology across bands. The approach works well if the sources in the scene have different colors and can be further strengthened by imposing various additional constraints/priors on each source. Because of its generic utility, this package provides a stand-alone implementation that contains the core components of the source separation algorithm. However, the development of this package is part of the LSST Science Pipeline; the meas_deblender package contains a wrapper to implement the algorithms here for the LSST stack.

Joint Source-Channel Decoding of Variable-Length Codes with Soft Information: A Survey

NASA Astrophysics Data System (ADS)

Guillemot, Christine; Siohan, Pierre

2005-12-01

Multimedia transmission over time-varying wireless channels presents a number of challenges beyond existing capabilities conceived so far for third-generation networks. Efficient quality-of-service (QoS) provisioning for multimedia on these channels may in particular require a loosening and a rethinking of the layer separation principle. In that context, joint source-channel decoding (JSCD) strategies have gained attention as viable alternatives to separate decoding of source and channel codes. A statistical framework based on hidden Markov models (HMM) capturing dependencies between the source and channel coding components sets the foundation for optimal design of techniques of joint decoding of source and channel codes. The problem has been largely addressed in the research community, by considering both fixed-length codes (FLC) and variable-length source codes (VLC) widely used in compression standards. Joint source-channel decoding of VLC raises specific difficulties due to the fact that the segmentation of the received bitstream into source symbols is random. This paper makes a survey of recent theoretical and practical advances in the area of JSCD with soft information of VLC-encoded sources. It first describes the main paths followed for designing efficient estimators for VLC-encoded sources, the key component of the JSCD iterative structure. It then presents the main issues involved in the application of the turbo principle to JSCD of VLC-encoded sources as well as the main approaches to source-controlled channel decoding. This survey terminates by performance illustrations with real image and video decoding systems.

3D Multispecies Nonlinear Perturbative Particle Simulation of Intense Nonneutral Particle Beams (Research supported by the Department of Energy and the Short Pulse Spallation Source Project and LANSCE Division of LANL.)

NASA Astrophysics Data System (ADS)

Qin, Hong; Davidson, Ronald C.; Lee, W. Wei-Li

1999-11-01

The Beam Equilibrium Stability and Transport (BEST) code, a 3D multispecies nonlinear perturbative particle simulation code, has been developed to study collective effects in intense charged particle beams described self-consistently by the Vlasov-Maxwell equations. A Darwin model is adopted for transverse electromagnetic effects. As a 3D multispecies perturbative particle simulation code, it provides several unique capabilities. Since the simulation particles are used to simulate only the perturbed distribution function and self-fields, the simulation noise is reduced significantly. The perturbative approach also enables the code to investigate different physics effects separately, as well as simultaneously. The code can be easily switched between linear and nonlinear operation, and used to study both linear stability properties and nonlinear beam dynamics. These features, combined with 3D and multispecies capabilities, provides an effective tool to investigate the electron-ion two-stream instability, periodically focused solutions in alternating focusing fields, and many other important problems in nonlinear beam dynamics and accelerator physics. Applications to the two-stream instability are presented.

ITS version 5.0 : the integrated TIGER series of coupled electron/photon Monte Carlo transport codes.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Franke, Brian Claude; Kensek, Ronald Patrick; Laub, Thomas William

ITS is a powerful and user-friendly software package permitting state of the art Monte Carlo solution of linear time-independent couple electron/photon radiation transport problems, with or without the presence of macroscopic electric and magnetic fields of arbitrary spatial dependence. Our goal has been to simultaneously maximize operational simplicity and physical accuracy. Through a set of preprocessor directives, the user selects one of the many ITS codes. The ease with which the makefile system is applied combines with an input scheme based on order-independent descriptive keywords that makes maximum use of defaults and internal error checking to provide experimentalists and theoristsmore » alike with a method for the routine but rigorous solution of sophisticated radiation transport problems. Physical rigor is provided by employing accurate cross sections, sampling distributions, and physical models for describing the production and transport of the electron/photon cascade from 1.0 GeV down to 1.0 keV. The availability of source code permits the more sophisticated user to tailor the codes to specific applications and to extend the capabilities of the codes to more complex applications. Version 5.0, the latest version of ITS, contains (1) improvements to the ITS 3.0 continuous-energy codes, (2)multigroup codes with adjoint transport capabilities, and (3) parallel implementations of all ITS codes. Moreover the general user friendliness of the software has been enhanced through increased internal error checking and improved code portability.« less

Plant identification credibility in ethnobotany: a closer look at Polish ethnographic studies

PubMed Central

2010-01-01

Background This paper is an attempt to estimate the percentage of erroneously identified taxa in ethnographic studies concerning the use of plants and to propose a code for recording credibility of identification in historical ethnobotany publications. Methods A sample of Polish-language ethnobotanical literature (45 published sources from 1874-2005) and four collections of voucher specimens (from 1894-1975) were analyzed. Errors were detected in the publications by comparing the data with existing knowledge on the distribution of plant names and species ranges. The voucher specimens were re-examined. A one-letter code was invented for quick identification of the credibility of data published in lists of species compiled from historical or ethnographic sources, according to the source of identification: voucher specimen, Latin binominal, botanical expert, obvious widespread name, folk name, mode of use, range, physical description or photograph. To test the use of the code an up-to-date list of wild food plants used in Poland was made. Results A significant difference between the ratio of mistakes in the voucher specimen collections and the ratio of detectable mistakes in the studies without herbarium documentation was found. At least 2.3% of taxa in the publications were identified erroneously (mean rate was 6.2% per publication), and in half of these mistakes even the genus was not correct. As many as 10.0% of voucher specimens (on average 9.2% per collection) were originally erroneously identified, but three quarters of the identification mistakes remained within-genus. The species of the genera Thymus, Rumex and Rubus were most often confused within the genus. Not all of the invented credibility codes were used in the list of wild food plants, but they may be useful for other researchers. The most often used codes were the ones signifying identification by: voucher specimen, botanical expert and by a common name used throughout the country. Conclusions The results of this study support the rigorous use of voucher specimens in ethnobotany, although they also reveal a relatively high percentage of misidentified taxa in the specimens studied. The invented credibility coding system may become a useful tool for communication between historical ethnobotanists, particularly in creating larger databases. PMID:21167056

A comparison study on various low energy sources in interstitial prostate brachytherapy

PubMed Central

Bakhshabadi, Mahdi; Ghorbani, Mahdi; Knaup, Courtney; Meigooni, Ali S.

2016-01-01

Purpose Low energy sources are routinely used in prostate brachytherapy. 125I is one of the most commonly used sources. Low energy 131Cs source was introduced recently as a brachytherapy source. The aim of this study is to compare dose distributions of 125I, 103Pd, and 131Cs sources in interstitial brachytherapy of prostate. Material and methods ProstaSeed 125I brachytherapy source was simulated using MCNPX Monte Carlo code. Additionally, two hypothetical sources of 103Pd and 131Cs were simulated with the same geometry as the ProstaSeed 125I source, while having their specific emitted gamma spectra. These brachytherapy sources were simulated with distribution of forty-eight seeds in a phantom including prostate. The prostate was considered as a sphere with radius of 1.5 cm. Absolute and relative dose rates were obtained in various distances from the source along the transverse and longitudinal axes inside and outside the tumor. Furthermore, isodose curves were plotted around the sources. Results Analyzing the initial dose profiles for various sources indicated that with the same time duration and air kerma strength, 131Cs delivers higher dose to tumor. However, relative dose rate inside the tumor is higher and outside the tumor is lower for the 103Pd source. Conclusions The higher initial absolute dose in cGy/(h.U) of 131Cs brachytherapy source is an advantage of this source over the others. The higher relative dose inside the tumor and lower relative dose outside the tumor for the 103Pd source are advantages of this later brachytherapy source. Based on the total dose the 125I source has advantage over the others due to its longer half-life. PMID:26985200

A comparison study on various low energy sources in interstitial prostate brachytherapy.

PubMed

Bakhshabadi, Mahdi; Ghorbani, Mahdi; Khosroabadi, Mohsen; Knaup, Courtney; Meigooni, Ali S

2016-02-01

Low energy sources are routinely used in prostate brachytherapy. (125)I is one of the most commonly used sources. Low energy (131)Cs source was introduced recently as a brachytherapy source. The aim of this study is to compare dose distributions of (125)I, (103)Pd, and (131)Cs sources in interstitial brachytherapy of prostate. ProstaSeed (125)I brachytherapy source was simulated using MCNPX Monte Carlo code. Additionally, two hypothetical sources of (103)Pd and (131)Cs were simulated with the same geometry as the ProstaSeed (125)I source, while having their specific emitted gamma spectra. These brachytherapy sources were simulated with distribution of forty-eight seeds in a phantom including prostate. The prostate was considered as a sphere with radius of 1.5 cm. Absolute and relative dose rates were obtained in various distances from the source along the transverse and longitudinal axes inside and outside the tumor. Furthermore, isodose curves were plotted around the sources. Analyzing the initial dose profiles for various sources indicated that with the same time duration and air kerma strength, (131)Cs delivers higher dose to tumor. However, relative dose rate inside the tumor is higher and outside the tumor is lower for the (103)Pd source. The higher initial absolute dose in cGy/(h.U) of (131)Cs brachytherapy source is an advantage of this source over the others. The higher relative dose inside the tumor and lower relative dose outside the tumor for the (103)Pd source are advantages of this later brachytherapy source. Based on the total dose the (125)I source has advantage over the others due to its longer half-life.

Open-Source Development of the Petascale Reactive Flow and Transport Code PFLOTRAN

NASA Astrophysics Data System (ADS)

Hammond, G. E.; Andre, B.; Bisht, G.; Johnson, T.; Karra, S.; Lichtner, P. C.; Mills, R. T.

2013-12-01

Open-source software development has become increasingly popular in recent years. Open-source encourages collaborative and transparent software development and promotes unlimited free redistribution of source code to the public. Open-source development is good for science as it reveals implementation details that are critical to scientific reproducibility, but generally excluded from journal publications. In addition, research funds that would have been spent on licensing fees can be redirected to code development that benefits more scientists. In 2006, the developers of PFLOTRAN open-sourced their code under the U.S. Department of Energy SciDAC-II program. Since that time, the code has gained popularity among code developers and users from around the world seeking to employ PFLOTRAN to simulate thermal, hydraulic, mechanical and biogeochemical processes in the Earth's surface/subsurface environment. PFLOTRAN is a massively-parallel subsurface reactive multiphase flow and transport simulator designed from the ground up to run efficiently on computing platforms ranging from the laptop to leadership-class supercomputers, all from a single code base. The code employs domain decomposition for parallelism and is founded upon the well-established and open-source parallel PETSc and HDF5 frameworks. PFLOTRAN leverages modern Fortran (i.e. Fortran 2003-2008) in its extensible object-oriented design. The use of this progressive, yet domain-friendly programming language has greatly facilitated collaboration in the code's software development. Over the past year, PFLOTRAN's top-level data structures were refactored as Fortran classes (i.e. extendible derived types) to improve the flexibility of the code, ease the addition of new process models, and enable coupling to external simulators. For instance, PFLOTRAN has been coupled to the parallel electrical resistivity tomography code E4D to enable hydrogeophysical inversion while the same code base can be used as a third-party library to provide hydrologic flow, energy transport, and biogeochemical capability to the community land model, CLM, part of the open-source community earth system model (CESM) for climate. In this presentation, the advantages and disadvantages of open source software development in support of geoscience research at government laboratories, universities, and the private sector are discussed. Since the code is open-source (i.e. it's transparent and readily available to competitors), the PFLOTRAN team's development strategy within a competitive research environment is presented. Finally, the developers discuss their approach to object-oriented programming and the leveraging of modern Fortran in support of collaborative geoscience research as the Fortran standard evolves among compiler vendors.

Multidimensional incremental parsing for universal source coding.

PubMed

Bae, Soo Hyun; Juang, Biing-Hwang

2008-10-01

A multidimensional incremental parsing algorithm (MDIP) for multidimensional discrete sources, as a generalization of the Lempel-Ziv coding algorithm, is investigated. It consists of three essential component schemes, maximum decimation matching, hierarchical structure of multidimensional source coding, and dictionary augmentation. As a counterpart of the longest match search in the Lempel-Ziv algorithm, two classes of maximum decimation matching are studied. Also, an underlying behavior of the dictionary augmentation scheme for estimating the source statistics is examined. For an m-dimensional source, m augmentative patches are appended into the dictionary at each coding epoch, thus requiring the transmission of a substantial amount of information to the decoder. The property of the hierarchical structure of the source coding algorithm resolves this issue by successively incorporating lower dimensional coding procedures in the scheme. In regard to universal lossy source coders, we propose two distortion functions, the local average distortion and the local minimax distortion with a set of threshold levels for each source symbol. For performance evaluation, we implemented three image compression algorithms based upon the MDIP; one is lossless and the others are lossy. The lossless image compression algorithm does not perform better than the Lempel-Ziv-Welch coding, but experimentally shows efficiency in capturing the source structure. The two lossy image compression algorithms are implemented using the two distortion functions, respectively. The algorithm based on the local average distortion is efficient at minimizing the signal distortion, but the images by the one with the local minimax distortion have a good perceptual fidelity among other compression algorithms. Our insights inspire future research on feature extraction of multidimensional discrete sources.

Changes in mitochondrial genetic codes as phylogenetic characters: Two examples from the flatworms

PubMed Central

Telford, Maximilian J.; Herniou, Elisabeth A.; Russell, Robert B.; Littlewood, D. Timothy J.

2000-01-01

Shared molecular genetic characteristics other than DNA and protein sequences can provide excellent sources of phylogenetic information, particularly if they are complex and rare and are consequently unlikely to have arisen by chance convergence. We have used two such characters, arising from changes in mitochondrial genetic code, to define a clade within the Platyhelminthes (flatworms), the Rhabditophora. We have sampled 10 distinct classes within the Rhabditophora and find that all have the codon AAA coding for the amino acid Asn rather than the usual Lys and AUA for Ile rather than the usual Met. We find no evidence to support claims that the codon UAA codes for Tyr in the Platyhelminthes rather than the standard stop codon. The Rhabditophora are a very diverse group comprising the majority of the free-living turbellarian taxa and the parasitic Neodermata. In contrast, three other classes of turbellarian flatworm, the Acoela, Nemertodermatida, and Catenulida, have the standard invertebrate assignments for these codons and so are convincingly excluded from the rhabditophoran clade. We have developed a rapid computerized method for analyzing genetic codes and demonstrate the wide phylogenetic distribution of the standard invertebrate code as well as confirming already known metazoan deviations from it (ascidian, vertebrate, echinoderm/hemichordate). PMID:11027335

SKIRT: The design of a suite of input models for Monte Carlo radiative transfer simulations

NASA Astrophysics Data System (ADS)

Baes, M.; Camps, P.

2015-09-01

The Monte Carlo method is the most popular technique to perform radiative transfer simulations in a general 3D geometry. The algorithms behind and acceleration techniques for Monte Carlo radiative transfer are discussed extensively in the literature, and many different Monte Carlo codes are publicly available. On the contrary, the design of a suite of components that can be used for the distribution of sources and sinks in radiative transfer codes has received very little attention. The availability of such models, with different degrees of complexity, has many benefits. For example, they can serve as toy models to test new physical ingredients, or as parameterised models for inverse radiative transfer fitting. For 3D Monte Carlo codes, this requires algorithms to efficiently generate random positions from 3D density distributions. We describe the design of a flexible suite of components for the Monte Carlo radiative transfer code SKIRT. The design is based on a combination of basic building blocks (which can be either analytical toy models or numerical models defined on grids or a set of particles) and the extensive use of decorators that combine and alter these building blocks to more complex structures. For a number of decorators, e.g. those that add spiral structure or clumpiness, we provide a detailed description of the algorithms that can be used to generate random positions. Advantages of this decorator-based design include code transparency, the avoidance of code duplication, and an increase in code maintainability. Moreover, since decorators can be chained without problems, very complex models can easily be constructed out of simple building blocks. Finally, based on a number of test simulations, we demonstrate that our design using customised random position generators is superior to a simpler design based on a generic black-box random position generator.

AERO2S - SUBSONIC AERODYNAMIC ANALYSIS OF WINGS WITH LEADING- AND TRAILING-EDGE FLAPS IN COMBINATION WITH CANARD OR HORIZONTAL TAIL SURFACES (IBM PC VERSION)

NASA Technical Reports Server (NTRS)

Carlson, H. W.

1994-01-01

This code was developed to aid design engineers in the selection and evaluation of aerodynamically efficient wing-canard and wing-horizontal-tail configurations that may employ simple hinged-flap systems. Rapid estimates of the longitudinal aerodynamic characteristics of conceptual airplane lifting surface arrangements are provided. The method is particularly well suited to configurations which, because of high speed flight requirements, must employ thin wings with highly swept leading edges. The code is applicable to wings with either sharp or rounded leading edges. The code provides theoretical pressure distributions over the wing, the canard or horizontal tail, and the deflected flap surfaces as well as estimates of the wing lift, drag, and pitching moments which account for attainable leading edge thrust and leading edge separation vortex forces. The wing planform information is specified by a series of leading edge and trailing edge breakpoints for a right hand wing panel. Up to 21 pairs of coordinates may be used to describe both the leading edge and the trailing edge. The code has been written to accommodate 2000 right hand panel elements, but can easily be modified to accommodate a larger or smaller number of elements depending on the capacity of the target computer platform. The code provides solutions for wing surfaces composed of all possible combinations of leading edge and trailing edge flap settings provided by the original deflection multipliers and by the flap deflection multipliers. Up to 25 pairs of leading edge and trailing edge flap deflection schedules may thus be treated simultaneously. The code also provides for an improved accounting of hinge-line singularities in determination of wing forces and moments. To determine lifting surface perturbation velocity distributions, the code provides for a maximum of 70 iterations. The program is constructed so that successive runs may be made with a given code entry. To make additional runs, it is necessary only to add an identification record and the namelist data that are to be changed from the previous run. This code was originally developed in 1989 in FORTRAN V on a CDC 6000 computer system, and was later ported to an MS-DOS environment. Both versions are available from COSMIC. There are only a few differences between the PC version (LAR-14458) and CDC version (LAR-14178) of AERO2S distributed by COSMIC. The CDC version has one main source code file while the PC version has two files which are easier to edit and compile on a PC. The PC version does not require a FORTRAN compiler which supports NAMELIST because a special INPUT subroutine has been added. The CDC version includes two MODIFY decks which can be used to improve the code and prevent the possibility of some infrequently occurring errors while PC-version users will have to make these code changes manually. The PC version includes an executable which was generated with the Ryan McFarland/FORTRAN compiler and requires 253K RAM and an 80x87 math co-processor. Using this executable, the sample case requires about four hours to execute on an 8MHz AT-class microcomputer with a co-processor. The source code conforms to the FORTRAN 77 standard except that it uses variables longer than six characters. With two minor modifications, the PC version should be portable to any computer with a FORTRAN compiler and sufficient memory. The CDC version of AERO2S is available in CDC NOS Internal format on a 9-track 1600 BPI magnetic tape. The PC version is available on a set of two 5.25 inch 360K MS-DOS format diskettes. IBM AT is a registered trademark of International Business Machines. MS-DOS is a registered trademark of Microsoft Corporation. CDC is a registered trademark of Control Data Corporation. NOS is a trademark of Control Data Corporation.

AERO2S - SUBSONIC AERODYNAMIC ANALYSIS OF WINGS WITH LEADING- AND TRAILING-EDGE FLAPS IN COMBINATION WITH CANARD OR HORIZONTAL TAIL SURFACES (CDC VERSION)

NASA Technical Reports Server (NTRS)

Darden, C. M.

1994-01-01

This code was developed to aid design engineers in the selection and evaluation of aerodynamically efficient wing-canard and wing-horizontal-tail configurations that may employ simple hinged-flap systems. Rapid estimates of the longitudinal aerodynamic characteristics of conceptual airplane lifting surface arrangements are provided. The method is particularly well suited to configurations which, because of high speed flight requirements, must employ thin wings with highly swept leading edges. The code is applicable to wings with either sharp or rounded leading edges. The code provides theoretical pressure distributions over the wing, the canard or horizontal tail, and the deflected flap surfaces as well as estimates of the wing lift, drag, and pitching moments which account for attainable leading edge thrust and leading edge separation vortex forces. The wing planform information is specified by a series of leading edge and trailing edge breakpoints for a right hand wing panel. Up to 21 pairs of coordinates may be used to describe both the leading edge and the trailing edge. The code has been written to accommodate 2000 right hand panel elements, but can easily be modified to accommodate a larger or smaller number of elements depending on the capacity of the target computer platform. The code provides solutions for wing surfaces composed of all possible combinations of leading edge and trailing edge flap settings provided by the original deflection multipliers and by the flap deflection multipliers. Up to 25 pairs of leading edge and trailing edge flap deflection schedules may thus be treated simultaneously. The code also provides for an improved accounting of hinge-line singularities in determination of wing forces and moments. To determine lifting surface perturbation velocity distributions, the code provides for a maximum of 70 iterations. The program is constructed so that successive runs may be made with a given code entry. To make additional runs, it is necessary only to add an identification record and the namelist data that are to be changed from the previous run. This code was originally developed in 1989 in FORTRAN V on a CDC 6000 computer system, and was later ported to an MS-DOS environment. Both versions are available from COSMIC. There are only a few differences between the PC version (LAR-14458) and CDC version (LAR-14178) of AERO2S distributed by COSMIC. The CDC version has one main source code file while the PC version has two files which are easier to edit and compile on a PC. The PC version does not require a FORTRAN compiler which supports NAMELIST because a special INPUT subroutine has been added. The CDC version includes two MODIFY decks which can be used to improve the code and prevent the possibility of some infrequently occurring errors while PC-version users will have to make these code changes manually. The PC version includes an executable which was generated with the Ryan McFarland/FORTRAN compiler and requires 253K RAM and an 80x87 math co-processor. Using this executable, the sample case requires about four hours to execute on an 8MHz AT-class microcomputer with a co-processor. The source code conforms to the FORTRAN 77 standard except that it uses variables longer than six characters. With two minor modifications, the PC version should be portable to any computer with a FORTRAN compiler and sufficient memory. The CDC version of AERO2S is available in CDC NOS Internal format on a 9-track 1600 BPI magnetic tape. The PC version is available on a set of two 5.25 inch 360K MS-DOS format diskettes. IBM AT is a registered trademark of International Business Machines. MS-DOS is a registered trademark of Microsoft Corporation. CDC is a registered trademark of Control Data Corporation. NOS is a trademark of Control Data Corporation.

E-Standards For Mass Properties Engineering

NASA Technical Reports Server (NTRS)

Cerro, Jeffrey A.

2008-01-01

A proposal is put forth to promote the concept of a Society of Allied Weight Engineers developed voluntary consensus standard for mass properties engineering. This standard would be an e-standard, and would encompass data, data manipulation, and reporting functionality. The standard would be implemented via an open-source SAWE distribution site with full SAWE member body access. Engineering societies and global standards initiatives are progressing toward modern engineering standards, which become functioning deliverable data sets. These data sets, if properly standardized, will integrate easily between supplier and customer enabling technically precise mass properties data exchange. The concepts of object-oriented programming support all of these requirements, and the use of a JavaTx based open-source development initiative is proposed. Results are reported for activity sponsored by the NASA Langley Research Center Innovation Institute to scope out requirements for developing a mass properties engineering e-standard. An initial software distribution is proposed. Upon completion, an open-source application programming interface will be available to SAWE members for the development of more specific programming requirements that are tailored to company and project requirements. A fully functioning application programming interface will permit code extension via company proprietary techniques, as well as through continued open-source initiatives.

Consistent Adjoint Driven Importance Sampling using Space, Energy and Angle

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peplow, Douglas E.; Mosher, Scott W; Evans, Thomas M

2012-08-01

For challenging radiation transport problems, hybrid methods combine the accuracy of Monte Carlo methods with the global information present in deterministic methods. One of the most successful hybrid methods is CADIS Consistent Adjoint Driven Importance Sampling. This method uses a deterministic adjoint solution to construct a biased source distribution and consistent weight windows to optimize a specific tally in a Monte Carlo calculation. The method has been implemented into transport codes using just the spatial and energy information from the deterministic adjoint and has been used in many applications to compute tallies with much higher figures-of-merit than analog calculations. CADISmore » also outperforms user-supplied importance values, which usually take long periods of user time to develop. This work extends CADIS to develop weight windows that are a function of the position, energy, and direction of the Monte Carlo particle. Two types of consistent source biasing are presented: one method that biases the source in space and energy while preserving the original directional distribution and one method that biases the source in space, energy, and direction. Seven simple example problems are presented which compare the use of the standard space/energy CADIS with the new space/energy/angle treatments.« less

Source Code Plagiarism--A Student Perspective

ERIC Educational Resources Information Center

Joy, M.; Cosma, G.; Yau, J. Y.-K.; Sinclair, J.

2011-01-01

This paper considers the problem of source code plagiarism by students within the computing disciplines and reports the results of a survey of students in Computing departments in 18 institutions in the U.K. This survey was designed to investigate how well students understand the concept of source code plagiarism and to discover what, if any,…

On the optimum signal constellation design for high-speed optical transport networks.

PubMed

Liu, Tao; Djordjevic, Ivan B

2012-08-27

In this paper, we first describe an optimum signal constellation design algorithm, which is optimum in MMSE-sense, called MMSE-OSCD, for channel capacity achieving source distribution. Secondly, we introduce a feedback channel capacity inspired optimum signal constellation design (FCC-OSCD) to further improve the performance of MMSE-OSCD, inspired by the fact that feedback channel capacity is higher than that of systems without feedback. The constellations obtained by FCC-OSCD are, however, OSNR dependent. The optimization is jointly performed together with regular quasi-cyclic low-density parity-check (LDPC) code design. Such obtained coded-modulation scheme, in combination with polarization-multiplexing, is suitable as both 400 Gb/s and multi-Tb/s optical transport enabling technology. Using large girth LDPC code, we demonstrate by Monte Carlo simulations that a 32-ary signal constellation, obtained by FCC-OSCD, outperforms previously proposed optimized 32-ary CIPQ signal constellation by 0.8 dB at BER of 10(-7). On the other hand, the LDPC-coded 16-ary FCC-OSCD outperforms 16-QAM by 1.15 dB at the same BER.

Design of Distortion-Invariant Optical ID Tags for Remote Identification and Verification of Objects

NASA Astrophysics Data System (ADS)

Pérez-Cabré, Elisabet; Millán, María Sagrario; Javidi, Bahram

Optical identification (ID) tags [1] have a promising future in a number of applications such as the surveillance of vehicles in transportation, control of restricted areas for homeland security, item tracking on conveyor belts or other industrial environment, etc. More specifically, passive optical ID tag [1] was introduced as an optical code containing a signature (that is, a characteristic image or other relevant information of the object), which permits its real-time remote detection and identification. Since their introduction in the literature [1], some contributions have been proposed to increase their usefulness and robustness. To increase security and avoid counterfeiting, the signature was introduced in the optical code as an encrypted function [2-5] following the double-phase encryption technique [6]. Moreover, the design of the optical ID tag was done in such a way that tolerance to variations in scale and rotation was achieved [2-5]. To do that, the encrypted information was multiplexed and distributed in the optical code following an appropriate topology. Further studies were carried out to analyze the influence of different sources of noise. In some proposals [5, 7], the designed ID tag consists of two optical codes where the complex-valued encrypted signature was separately introduced in two real-valued functions according to its magnitude and phase distributions. This solution was introduced to overcome some difficulties in the readout of complex values in outdoors environments. Recently, the fully phase encryption technique [8] has been proposed to increase noise robustness of the authentication system.

Maximum current density and beam brightness achievable by laser-driven electron sources

NASA Astrophysics Data System (ADS)

Filippetto, D.; Musumeci, P.; Zolotorev, M.; Stupakov, G.

2014-02-01

This paper discusses the extension to different electron beam aspect ratio of the Child-Langmuir law for the maximum achievable current density in electron guns. Using a simple model, we derive quantitative formulas in good agreement with simulation codes. The new scaling laws for the peak current density of temporally long and transversely narrow initial beam distributions can be used to estimate the maximum beam brightness and suggest new paths for injector optimization.

Integrated Support for Manipulation and Display of 3D Objects for the Command and Control Workstation of the Future

DTIC Science & Technology

1989-06-01

Science Unclassified SECURITY CLASSIFICATION OF THIS PAGE REPORT DOCUMENTATION PAGE la. REPORT SECURITY CLASS’r!CATION )b RESTRICTIVE MARKINGS UNCLASSIFIED...2a. SECURITY CLASSIFICATION AUTHORITY 3. DISTRIBUTION/AVAILABILITY OF REPORT Approved for public release; Zb. DECLASSIFICATION I DOWNGRADING SCHEDULE...ZIP Code) 10 SOURCE OF FUNDING NUMBERS PROGRAM PROJECT TASK WORK UNIT Monterey, CA. 93943 FLEMENT NO. NO. NO ACCESSION NO. 11. TITLE (Include Security

Clinical results of HIS, RIS, PACS integration using data integration CASE tools

NASA Astrophysics Data System (ADS)

Taira, Ricky K.; Chan, Hing-Ming; Breant, Claudine M.; Huang, Lu J.; Valentino, Daniel J.

1995-05-01

Current infrastructure research in PACS is dominated by the development of communication networks (local area networks, teleradiology, ATM networks, etc.), multimedia display workstations, and hierarchical image storage architectures. However, limited work has been performed on developing flexible, expansible, and intelligent information processing architectures for the vast decentralized image and text data repositories prevalent in healthcare environments. Patient information is often distributed among multiple data management systems. Current large-scale efforts to integrate medical information and knowledge sources have been costly with limited retrieval functionality. Software integration strategies to unify distributed data and knowledge sources is still lacking commercially. Systems heterogeneity (i.e., differences in hardware platforms, communication protocols, database management software, nomenclature, etc.) is at the heart of the problem and is unlikely to be standardized in the near future. In this paper, we demonstrate the use of newly available CASE (computer- aided software engineering) tools to rapidly integrate HIS, RIS, and PACS information systems. The advantages of these tools include fast development time (low-level code is generated from graphical specifications), and easy system maintenance (excellent documentation, easy to perform changes, and centralized code repository in an object-oriented database). The CASE tools are used to develop and manage the `middle-ware' in our client- mediator-serve architecture for systems integration. Our architecture is scalable and can accommodate heterogeneous database and communication protocols.

Recent advances in coding theory for near error-free communications

NASA Technical Reports Server (NTRS)

Cheung, K.-M.; Deutsch, L. J.; Dolinar, S. J.; Mceliece, R. J.; Pollara, F.; Shahshahani, M.; Swanson, L.

1991-01-01

Channel and source coding theories are discussed. The following subject areas are covered: large constraint length convolutional codes (the Galileo code); decoder design (the big Viterbi decoder); Voyager's and Galileo's data compression scheme; current research in data compression for images; neural networks for soft decoding; neural networks for source decoding; finite-state codes; and fractals for data compression.

Evaluation of the Effect of Source Geometry on the Output of Miniature X-ray Tube for Electronic Brachytherapy through Simulation

PubMed Central

Barati, B.; Zabihzadeh, M.; Tahmasebi Birgani, M.J.; Chegini, N.; Fatahiasl, J.; Mirr, I.

2018-01-01

Objective: The use of miniature X-ray source in electronic brachytherapy is on the rise so there is an urgent need to acquire more knowledge on X-ray spectrum production and distribution by a dose. The aim of this research was to investigate the influence of target thickness and geometry at the source of miniature X-ray tube on tube output. Method: Five sources were simulated based on problems each with a specific geometric structure and conditions using MCNPX code. Tallies proportional to the output were used to calculate the results for the influence of source geometry on output. Results: The results of this work include the size of the optimal thickness of 5 miniature sources, energy spectrum of the sources per 50 kev and also the axial and transverse dose of simulated sources were calculated based on these thicknesses. The miniature source geometric was affected on the output x-ray tube. Conclusion: The result of this study demonstrates that hemispherical-conical, hemispherical and truncated-conical miniature sources were determined as the most suitable tools. PMID:29732338

Hybrid concatenated codes and iterative decoding

NASA Technical Reports Server (NTRS)

Divsalar, Dariush (Inventor); Pollara, Fabrizio (Inventor)

2000-01-01

Several improved turbo code apparatuses and methods. The invention encompasses several classes: (1) A data source is applied to two or more encoders with an interleaver between the source and each of the second and subsequent encoders. Each encoder outputs a code element which may be transmitted or stored. A parallel decoder provides the ability to decode the code elements to derive the original source information d without use of a received data signal corresponding to d. The output may be coupled to a multilevel trellis-coded modulator (TCM). (2) A data source d is applied to two or more encoders with an interleaver between the source and each of the second and subsequent encoders. Each of the encoders outputs a code element. In addition, the original data source d is output from the encoder. All of the output elements are coupled to a TCM. (3) At least two data sources are applied to two or more encoders with an interleaver between each source and each of the second and subsequent encoders. The output may be coupled to a TCM. (4) At least two data sources are applied to two or more encoders with at least two interleavers between each source and each of the second and subsequent encoders. (5) At least one data source is applied to one or more serially linked encoders through at least one interleaver. The output may be coupled to a TCM. The invention includes a novel way of terminating a turbo coder.

Monte Carlo N Particle code - Dose distribution of clinical electron beams in inhomogeneous phantoms

PubMed Central

Nedaie, H. A.; Mosleh-Shirazi, M. A.; Allahverdi, M.

2013-01-01

Electron dose distributions calculated using the currently available analytical methods can be associated with large uncertainties. The Monte Carlo method is the most accurate method for dose calculation in electron beams. Most of the clinical electron beam simulation studies have been performed using non- MCNP [Monte Carlo N Particle] codes. Given the differences between Monte Carlo codes, this work aims to evaluate the accuracy of MCNP4C-simulated electron dose distributions in a homogenous phantom and around inhomogeneities. Different types of phantoms ranging in complexity were used; namely, a homogeneous water phantom and phantoms made of polymethyl methacrylate slabs containing different-sized, low- and high-density inserts of heterogeneous materials. Electron beams with 8 and 15 MeV nominal energy generated by an Elekta Synergy linear accelerator were investigated. Measurements were performed for a 10 cm × 10 cm applicator at a source-to-surface distance of 100 cm. Individual parts of the beam-defining system were introduced into the simulation one at a time in order to show their effect on depth doses. In contrast to the first scattering foil, the secondary scattering foil, X and Y jaws and applicator provide up to 5% of the dose. A 2%/2 mm agreement between MCNP and measurements was found in the homogenous phantom, and in the presence of heterogeneities in the range of 1-3%, being generally within 2% of the measurements for both energies in a "complex" phantom. A full-component simulation is necessary in order to obtain a realistic model of the beam. The MCNP4C results agree well with the measured electron dose distributions. PMID:23533162

SU-F-T-12: Monte Carlo Dosimetry of the 60Co Bebig High Dose Rate Source for Brachytherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Campos, L T; Almeida, C E V de

Purpose: The purpose of this work is to obtain the dosimetry parameters in accordance with the AAPM TG-43U1 formalism with Monte Carlo calculations regarding the BEBIG 60Co high-dose-rate brachytherapy. The geometric design and material details of the source was provided by the manufacturer and was used to define the Monte Carlo geometry. Methods: The dosimetry studies included the calculation of the air kerma strength Sk, collision kerma in water along the transverse axis with an unbounded phantom, dose rate constant and radial dose function. The Monte Carlo code system that was used was EGSnrc with a new cavity code, whichmore » is a part of EGS++ that allows calculating the radial dose function around the source. The XCOM photon cross-section library was used. Variance reduction techniques were used to speed up the calculation and to considerably reduce the computer time. To obtain the dose rate distributions of the source in an unbounded liquid water phantom, the source was immersed at the center of a cube phantom of 100 cm3. Results: The obtained dose rate constant for the BEBIG 60Co source was 1.108±0.001 cGyh-1U-1, which is consistent with the values in the literature. The radial dose functions were compared with the values of the consensus data set in the literature, and they are consistent with the published data for this energy range. Conclusion: The dose rate constant is consistent with the results of Granero et al. and Selvam and Bhola within 1%. Dose rate data are compared to GEANT4 and DORZnrc Monte Carlo code. However, the radial dose function is different by up to 10% for the points that are notably near the source on the transversal axis because of the high-energy photons from 60Co, which causes an electronic disequilibrium at the interface between the source capsule and the liquid water for distances up to 1 cm.« less

Comparison of theoretical and flight-measured local flow aerodynamics for a low-aspect-ratio fin

NASA Technical Reports Server (NTRS)

Johnson, J. B.; Sandlin, D. R.

1984-01-01

Flight test and theoretical aerodynamic data were obtained for a flight test fixture mounted on the underside of an F-104G aircraft. The theoretical data were generated using two codes, a two dimensional transonic code called Code H, and a three dimensional subsonic and supersonic code call wing-body. Pressure distributions generated by the codes for the flight test fixture as well as boundary layer displacement thickness generated by the two dimensional code were compared to the flight test data. The two dimensional code pressure distributions compared well except at the minimum pressure point and trailing edge. Shock locations compared well except at high transonic speeds. The three dimensional code pressure distributions compared well except at the trailing edge of the flight test fixture. The two dimensional code does not predict displacement thickness of the flight test fixture well.

Evaluation of Spanwise Variable Impedance Liners with Three-Dimensional Aeroacoustics Propagation Codes

NASA Technical Reports Server (NTRS)

Jones, M. G.; Watson, W. R.; Nark, D. M.; Schiller, N. H.

2017-01-01

Three perforate-over-honeycomb liner configurations, one uniform and two with spanwise variable impedance, are evaluated based on tests conducted in the NASA Grazing Flow Impedance Tube (GFIT) with a plane-wave source. Although the GFIT is only 2" wide, spanwise impedance variability clearly affects the measured acoustic pressure field, such that three-dimensional (3D) propagation codes are required to properly predict this acoustic pressure field. Three 3D propagation codes (CHE3D, COMSOL, and CDL) are used to predict the sound pressure level and phase at eighty-seven microphones flush-mounted in the GFIT (distributed along all four walls). The CHE3D and COMSOL codes compare favorably with the measured data, regardless of whether an exit acoustic pressure or anechoic boundary condition is employed. Except for those frequencies where the attenuation is large, the CDL code also provides acceptable estimates of the measured acoustic pressure profile. The CHE3D and COMSOL predictions diverge slightly from the measured data for frequencies away from resonance, where the attenuation is noticeably reduced, particularly when an exit acoustic pressure boundary condition is used. For these conditions, the CDL code actually provides slightly more favorable comparison with the measured data. Overall, the comparisons of predicted and measured data suggest that any of these codes can be used to understand data trends associated with spanwise variable-impedance liners.

Performing aggressive code optimization with an ability to rollback changes made by the aggressive optimizations

DOEpatents

Gschwind, Michael K

2013-07-23

Mechanisms for aggressively optimizing computer code are provided. With these mechanisms, a compiler determines an optimization to apply to a portion of source code and determines if the optimization as applied to the portion of source code will result in unsafe optimized code that introduces a new source of exceptions being generated by the optimized code. In response to a determination that the optimization is an unsafe optimization, the compiler generates an aggressively compiled code version, in which the unsafe optimization is applied, and a conservatively compiled code version in which the unsafe optimization is not applied. The compiler stores both versions and provides them for execution. Mechanisms are provided for switching between these versions during execution in the event of a failure of the aggressively compiled code version. Moreover, predictive mechanisms are provided for predicting whether such a failure is likely.

FORM version 4.0

NASA Astrophysics Data System (ADS)

Kuipers, J.; Ueda, T.; Vermaseren, J. A. M.; Vollinga, J.

2013-05-01

We present version 4.0 of the symbolic manipulation system FORM. The most important new features are manipulation of rational polynomials and the factorization of expressions. Many other new functions and commands are also added; some of them are very general, while others are designed for building specific high level packages, such as one for Gröbner bases. New is also the checkpoint facility, that allows for periodic backups during long calculations. Finally, FORM 4.0 has become available as open source under the GNU General Public License version 3. Program summaryProgram title: FORM. Catalogue identifier: AEOT_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEOT_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: GNU General Public License, version 3 No. of lines in distributed program, including test data, etc.: 151599 No. of bytes in distributed program, including test data, etc.: 1 078 748 Distribution format: tar.gz Programming language: The FORM language. FORM itself is programmed in a mixture of C and C++. Computer: All. Operating system: UNIX, LINUX, Mac OS, Windows. Classification: 5. Nature of problem: FORM defines a symbolic manipulation language in which the emphasis lies on fast processing of very large formulas. It has been used successfully for many calculations in Quantum Field Theory and mathematics. In speed and size of formulas that can be handled it outperforms other systems typically by an order of magnitude. Special in this version: The version 4.0 contains many new features. Most important are factorization and rational arithmetic. The program has also become open source under the GPL. The code in CPC is for reference. You are encouraged to upload the most recent sources from www.nikhef.nl/form/formcvs.php because of frequent bug fixes. Solution method: See "Nature of Problem", above. Additional comments: NOTE: The code in CPC is for reference. You are encouraged to upload the most recent sources from www.nikhef.nl/form/formcvs.php because of frequent bug fixes.

Distributed Learning, Recognition, and Prediction by ART and ARTMAP Neural Networks.

PubMed

Carpenter, Gail A.

1997-11-01

A class of adaptive resonance theory (ART) models for learning, recognition, and prediction with arbitrarily distributed code representations is introduced. Distributed ART neural networks combine the stable fast learning capabilities of winner-take-all ART systems with the noise tolerance and code compression capabilities of multilayer perceptrons. With a winner-take-all code, the unsupervised model dART reduces to fuzzy ART and the supervised model dARTMAP reduces to fuzzy ARTMAP. With a distributed code, these networks automatically apportion learned changes according to the degree of activation of each coding node, which permits fast as well as slow learning without catastrophic forgetting. Distributed ART models replace the traditional neural network path weight with a dynamic weight equal to the rectified difference between coding node activation and an adaptive threshold. Thresholds increase monotonically during learning according to a principle of atrophy due to disuse. However, monotonic change at the synaptic level manifests itself as bidirectional change at the dynamic level, where the result of adaptation resembles long-term potentiation (LTP) for single-pulse or low frequency test inputs but can resemble long-term depression (LTD) for higher frequency test inputs. This paradoxical behavior is traced to dual computational properties of phasic and tonic coding signal components. A parallel distributed match-reset-search process also helps stabilize memory. Without the match-reset-search system, dART becomes a type of distributed competitive learning network.

Advances in the computation of the Sjöstrand, Rossi, and Feynman distributions

DOE PAGES

Talamo, A.; Gohar, Y.; Gabrielli, F.; ...

2017-02-01

This study illustrates recent computational advances in the application of the Sjöstrand (area), Rossi, and Feynman methods to estimate the effective multiplication factor of a subcritical system driven by an external neutron source. The methodologies introduced in this study have been validated with the experimental results from the KUKA facility of Japan by Monte Carlo (MCNP6 and MCNPX) and deterministic (ERANOS, VARIANT, and PARTISN) codes. When the assembly is driven by a pulsed neutron source generated by a particle accelerator and delayed neutrons are at equilibrium, the Sjöstrand method becomes extremely fast if the integral of the reaction rate frommore » a single pulse is split into two parts. These two integrals distinguish between the neutron counts during and after the pulse period. To conclude, when the facility is driven by a spontaneous fission neutron source, the timestamps of the detector neutron counts can be obtained up to the nanosecond precision using MCNP6, which allows obtaining the Rossi and Feynman distributions.« less

SU-E-T-212: Comparison of TG-43 Dosimetric Parameters of Low and High Energy Brachytherapy Sources Obtained by MCNP Code Versions of 4C, X and 5

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zehtabian, M; Zaker, N; Sina, S

2015-06-15

Purpose: Different versions of MCNP code are widely used for dosimetry purposes. The purpose of this study is to compare different versions of the MCNP codes in dosimetric evaluation of different brachytherapy sources. Methods: The TG-43 parameters such as dose rate constant, radial dose function, and anisotropy function of different brachytherapy sources, i.e. Pd-103, I-125, Ir-192, and Cs-137 were calculated in water phantom. The results obtained by three versions of Monte Carlo codes (MCNP4C, MCNPX, MCNP5) were compared for low and high energy brachytherapy sources. Then the cross section library of MCNP4C code was changed to ENDF/B-VI release 8 whichmore » is used in MCNP5 and MCNPX codes. Finally, the TG-43 parameters obtained using the MCNP4C-revised code, were compared with other codes. Results: The results of these investigations indicate that for high energy sources, the differences in TG-43 parameters between the codes are less than 1% for Ir-192 and less than 0.5% for Cs-137. However for low energy sources like I-125 and Pd-103, large discrepancies are observed in the g(r) values obtained by MCNP4C and the two other codes. The differences between g(r) values calculated using MCNP4C and MCNP5 at the distance of 6cm were found to be about 17% and 28% for I-125 and Pd-103 respectively. The results obtained with MCNP4C-revised and MCNPX were similar. However, the maximum difference between the results obtained with the MCNP5 and MCNP4C-revised codes was 2% at 6cm. Conclusion: The results indicate that using MCNP4C code for dosimetry of low energy brachytherapy sources can cause large errors in the results. Therefore it is recommended not to use this code for low energy sources, unless its cross section library is changed. Since the results obtained with MCNP4C-revised and MCNPX were similar, it is concluded that the difference between MCNP4C and MCNPX is their cross section libraries.« less

Process Model Improvement for Source Code Plagiarism Detection in Student Programming Assignments

ERIC Educational Resources Information Center

Kermek, Dragutin; Novak, Matija

2016-01-01

In programming courses there are various ways in which students attempt to cheat. The most commonly used method is copying source code from other students and making minimal changes in it, like renaming variable names. Several tools like Sherlock, JPlag and Moss have been devised to detect source code plagiarism. However, for larger student…

Finding Resolution for the Responsible Transparency of Economic Models in Health and Medicine.

PubMed

Padula, William V; McQueen, Robert Brett; Pronovost, Peter J

2017-11-01

The Second Panel on Cost-Effectiveness in Health and Medicine recommendations for conduct, methodological practices, and reporting of cost-effectiveness analyses has a number of questions unanswered with respect to the implementation of transparent, open source code interface for economic models. The possibility of making economic model source code could be positive and progressive for the field; however, several unintended consequences of this system should be first considered before complete implementation of this model. First, there is the concern regarding intellectual property rights that modelers have to their analyses. Second, the open source code could make analyses more accessible to inexperienced modelers, leading to inaccurate or misinterpreted results. We propose several resolutions to these concerns. The field should establish a licensing system of open source code such that the model originators maintain control of the code use and grant permissions to other investigators who wish to use it. The field should also be more forthcoming towards the teaching of cost-effectiveness analysis in medical and health services education so that providers and other professionals are familiar with economic modeling and able to conduct analyses with open source code. These types of unintended consequences need to be fully considered before the field's preparedness to move forward into an era of model transparency with open source code.

Prediction of phosphorus loads in an artificially drained lowland catchment using a modified SWAT model

NASA Astrophysics Data System (ADS)

Bauwe, Andreas; Eckhardt, Kai-Uwe; Lennartz, Bernd

2017-04-01

Eutrophication is still one of the main environmental problems in the Baltic Sea. Currently, agricultural diffuse sources constitute the major portion of phosphorus (P) fluxes to the Baltic Sea and have to be reduced to achieve the HELCOM targets and improve the ecological status. Eco-hydrological models are suitable tools to identify sources of nutrients and possible measures aiming at reducing nutrient loads into surface waters. In this study, the Soil and Water Assessment Tool (SWAT) was applied to the Warnow river basin (3300 km2), the second largest watershed in Germany discharging into the Baltic Sea. The Warnow river basin is located in northeastern Germany and characterized by lowlands with a high proportion of artificially drained areas. The aim of this study were (i) to estimate P loadings for individual flow fractions (point sources, surface runoff, tile flow, groundwater flow), spatially distributed on sub-basin scale. Since the official version of SWAT does not allow for the modeling of P in tile drains, we tested (ii) two different approaches of simulating P in tile drains by changing the SWAT source code. The SWAT source code was modified so that (i) the soluble P concentration of the groundwater was transferred to the tile water and (ii) the soluble P in the soil was transferred to the tiles. The SWAT model was first calibrated (2002-2011) and validated (1992-2001) for stream flow at 7 headwater catchments at a daily time scale. Based on this, the stream flow at the outlet of the Warnow river basin was simulated. Performance statistics indicated at least satisfactory model results for each sub-basin. Breaking down the discharge into flow constituents, it becomes visible that stream flow is mainly governed by groundwater and tile flow. Due to the topographic situation with gentle slopes, surface runoff played only a minor role. Results further indicate that the prediction of soluble P loads was improved by the modified SWAT versions. Major sources of P in rivers are groundwater and tile flow. P was also released by surface runoff during large storm events when sediment was eroded into the rivers. The contributions of point sources in terms of waste water treatment plants to the overall P loading were low. The modifications made in the SWAT source code should be considered as a starting point to simulate P loads in artificially drained landscapes more precisely. Further testing and development of the code is required.

40 CFR 51.50 - What definitions apply to this subpart?

Code of Federal Regulations, 2010 CFR

2010-07-01

... accuracy description (MAD) codes means a set of six codes used to define the accuracy of latitude/longitude data for point sources. The six codes and their definitions are: (1) Coordinate Data Source Code: The... physical piece of or a closely related set of equipment. The EPA's reporting format for a given inventory...

PSRPOPPy: an open-source package for pulsar population simulations

NASA Astrophysics Data System (ADS)

Bates, S. D.; Lorimer, D. R.; Rane, A.; Swiggum, J.

2014-04-01

We have produced a new software package for the simulation of pulsar populations, PSRPOPPY, based on the PSRPOP package. The codebase has been re-written in Python (save for some external libraries, which remain in their native Fortran), utilizing the object-oriented features of the language, and improving the modularity of the code. Pre-written scripts are provided for running the simulations in `standard' modes of operation, but the code is flexible enough to support the writing of personalised scripts. The modular structure also makes the addition of experimental features (such as new models for period or luminosity distributions) more straightforward than with the previous code. We also discuss potential additions to the modelling capabilities of the software. Finally, we demonstrate some potential applications of the code; first, using results of surveys at different observing frequencies, we find pulsar spectral indices are best fitted by a normal distribution with mean -1.4 and standard deviation 1.0. Secondly, we model pulsar spin evolution to calculate the best fit for a relationship between a pulsar's luminosity and spin parameters. We used the code to replicate the analysis of Faucher-Giguère & Kaspi, and have subsequently optimized their power-law dependence of radio luminosity, L, with period, P, and period derivative, Ṗ. We find that the underlying population is best described by L ∝ P-1.39±0.09 Ṗ0.48±0.04 and is very similar to that found for γ-ray pulsars by Perera et al. Using this relationship, we generate a model population and examine the age-luminosity relation for the entire pulsar population, which may be measurable after future large-scale surveys with the Square Kilometre Array.

Mads.jl

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vesselinov, Velimir; O'Malley, Daniel; Lin, Youzuo

2016-07-01

Mads.jl (Model analysis and decision support in Julia) is a code that streamlines the process of using data and models for analysis and decision support. It is based on another open-source code developed at LANL and written in C/C++ (MADS; http://mads.lanl.gov; LA-CC-11- 035). Mads.jl can work with external models of arbitrary complexity as well as built-in models of flow and transport in porous media. It enables a number of data- and model-based analyses including model calibration, sensitivity analysis, uncertainty quantification, and decision analysis. The code also can use a series of alternative adaptive computational techniques for Bayesian sampling, Monte Carlo,more » and Bayesian Information-Gap Decision Theory. The code is implemented in the Julia programming language, and has high-performance (parallel) and memory management capabilities. The code uses a series of third party modules developed by others. The code development will also include contributions to the existing third party modules written in Julia; this contributions will be important for the efficient implementation of the algorithm used by Mads.jl. The code also uses a series of LANL developed modules that are developed by Dan O'Malley; these modules will be also a part of the Mads.jl release. Mads.jl will be released under GPL V3 license. The code will be distributed as a Git repo at gitlab.com and github.com. Mads.jl manual and documentation will be posted at madsjulia.lanl.gov.« less

The Astrophysics Source Code Library by the numbers

NASA Astrophysics Data System (ADS)

Allen, Alice; Teuben, Peter; Berriman, G. Bruce; DuPrie, Kimberly; Mink, Jessica; Nemiroff, Robert; Ryan, PW; Schmidt, Judy; Shamir, Lior; Shortridge, Keith; Wallin, John; Warmels, Rein

2018-01-01

The Astrophysics Source Code Library (ASCL, ascl.net) was founded in 1999 by Robert Nemiroff and John Wallin. ASCL editors seek both new and old peer-reviewed papers that describe methods or experiments that involve the development or use of source code, and add entries for the found codes to the library. Software authors can submit their codes to the ASCL as well. This ensures a comprehensive listing covering a significant number of the astrophysics source codes used in peer-reviewed studies. The ASCL is indexed by both NASA’s Astrophysics Data System (ADS) and Web of Science, making software used in research more discoverable. This presentation covers the growth in the ASCL’s number of entries, the number of citations to its entries, and in which journals those citations appear. It also discusses what changes have been made to the ASCL recently, and what its plans are for the future.

Astrophysics Source Code Library: Incite to Cite!

NASA Astrophysics Data System (ADS)

DuPrie, K.; Allen, A.; Berriman, B.; Hanisch, R. J.; Mink, J.; Nemiroff, R. J.; Shamir, L.; Shortridge, K.; Taylor, M. B.; Teuben, P.; Wallen, J. F.

2014-05-01

The Astrophysics Source Code Library (ASCl,http://ascl.net/) is an on-line registry of over 700 source codes that are of interest to astrophysicists, with more being added regularly. The ASCL actively seeks out codes as well as accepting submissions from the code authors, and all entries are citable and indexed by ADS. All codes have been used to generate results published in or submitted to a refereed journal and are available either via a download site or from an identified source. In addition to being the largest directory of scientist-written astrophysics programs available, the ASCL is also an active participant in the reproducible research movement with presentations at various conferences, numerous blog posts and a journal article. This poster provides a description of the ASCL and the changes that we are starting to see in the astrophysics community as a result of the work we are doing.

Astrophysics Source Code Library

NASA Astrophysics Data System (ADS)

Allen, A.; DuPrie, K.; Berriman, B.; Hanisch, R. J.; Mink, J.; Teuben, P. J.

2013-10-01

The Astrophysics Source Code Library (ASCL), founded in 1999, is a free on-line registry for source codes of interest to astronomers and astrophysicists. The library is housed on the discussion forum for Astronomy Picture of the Day (APOD) and can be accessed at http://ascl.net. The ASCL has a comprehensive listing that covers a significant number of the astrophysics source codes used to generate results published in or submitted to refereed journals and continues to grow. The ASCL currently has entries for over 500 codes; its records are citable and are indexed by ADS. The editors of the ASCL and members of its Advisory Committee were on hand at a demonstration table in the ADASS poster room to present the ASCL, accept code submissions, show how the ASCL is starting to be used by the astrophysics community, and take questions on and suggestions for improving the resource.

Generating code adapted for interlinking legacy scalar code and extended vector code

DOEpatents

Gschwind, Michael K

2013-06-04

Mechanisms for intermixing code are provided. Source code is received for compilation using an extended Application Binary Interface (ABI) that extends a legacy ABI and uses a different register configuration than the legacy ABI. First compiled code is generated based on the source code, the first compiled code comprising code for accommodating the difference in register configurations used by the extended ABI and the legacy ABI. The first compiled code and second compiled code are intermixed to generate intermixed code, the second compiled code being compiled code that uses the legacy ABI. The intermixed code comprises at least one call instruction that is one of a call from the first compiled code to the second compiled code or a call from the second compiled code to the first compiled code. The code for accommodating the difference in register configurations is associated with the at least one call instruction.

Reproducibility and Transparency in Ocean-Climate Modeling

NASA Astrophysics Data System (ADS)

Hannah, N.; Adcroft, A.; Hallberg, R.; Griffies, S. M.

2015-12-01

Reproducibility is a cornerstone of the scientific method. Within geophysical modeling and simulation achieving reproducibility can be difficult, especially given the complexity of numerical codes, enormous and disparate data sets, and variety of supercomputing technology. We have made progress on this problem in the context of a large project - the development of new ocean and sea ice models, MOM6 and SIS2. Here we present useful techniques and experience.We use version control not only for code but the entire experiment working directory, including configuration (run-time parameters, component versions), input data and checksums on experiment output. This allows us to document when the solutions to experiments change, whether due to code updates or changes in input data. To avoid distributing large input datasets we provide the tools for generating these from the sources, rather than provide raw input data.Bugs can be a source of non-determinism and hence irreproducibility, e.g. reading from or branching on uninitialized memory. To expose these we routinely run system tests, using a memory debugger, multiple compilers and different machines. Additional confidence in the code comes from specialised tests, for example automated dimensional analysis and domain transformations. This has entailed adopting a code style where we deliberately restrict what a compiler can do when re-arranging mathematical expressions.In the spirit of open science, all development is in the public domain. This leads to a positive feedback, where increased transparency and reproducibility makes using the model easier for external collaborators, who in turn provide valuable contributions. To facilitate users installing and running the model we provide (version controlled) digital notebooks that illustrate and record analysis of output. This has the dual role of providing a gross, platform-independent, testing capability and a means to documents model output and analysis.

Optimal power allocation and joint source-channel coding for wireless DS-CDMA visual sensor networks

NASA Astrophysics Data System (ADS)

Pandremmenou, Katerina; Kondi, Lisimachos P.; Parsopoulos, Konstantinos E.

2011-01-01

In this paper, we propose a scheme for the optimal allocation of power, source coding rate, and channel coding rate for each of the nodes of a wireless Direct Sequence Code Division Multiple Access (DS-CDMA) visual sensor network. The optimization is quality-driven, i.e. the received quality of the video that is transmitted by the nodes is optimized. The scheme takes into account the fact that the sensor nodes may be imaging scenes with varying levels of motion. Nodes that image low-motion scenes will require a lower source coding rate, so they will be able to allocate a greater portion of the total available bit rate to channel coding. Stronger channel coding will mean that such nodes will be able to transmit at lower power. This will both increase battery life and reduce interference to other nodes. Two optimization criteria are considered. One that minimizes the average video distortion of the nodes and one that minimizes the maximum distortion among the nodes. The transmission powers are allowed to take continuous values, whereas the source and channel coding rates can assume only discrete values. Thus, the resulting optimization problem lies in the field of mixed-integer optimization tasks and is solved using Particle Swarm Optimization. Our experimental results show the importance of considering the characteristics of the video sequences when determining the transmission power, source coding rate and channel coding rate for the nodes of the visual sensor network.

A generic high-dose rate {sup 192}Ir brachytherapy source for evaluation of model-based dose calculations beyond the TG-43 formalism

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ballester, Facundo, E-mail: Facundo.Ballester@uv.es; Carlsson Tedgren, Åsa; Granero, Domingo

Purpose: In order to facilitate a smooth transition for brachytherapy dose calculations from the American Association of Physicists in Medicine (AAPM) Task Group No. 43 (TG-43) formalism to model-based dose calculation algorithms (MBDCAs), treatment planning systems (TPSs) using a MBDCA require a set of well-defined test case plans characterized by Monte Carlo (MC) methods. This also permits direct dose comparison to TG-43 reference data. Such test case plans should be made available for use in the software commissioning process performed by clinical end users. To this end, a hypothetical, generic high-dose rate (HDR) {sup 192}Ir source and a virtual watermore » phantom were designed, which can be imported into a TPS. Methods: A hypothetical, generic HDR {sup 192}Ir source was designed based on commercially available sources as well as a virtual, cubic water phantom that can be imported into any TPS in DICOM format. The dose distribution of the generic {sup 192}Ir source when placed at the center of the cubic phantom, and away from the center under altered scatter conditions, was evaluated using two commercial MBDCAs [Oncentra{sup ®} Brachy with advanced collapsed-cone engine (ACE) and BrachyVision ACUROS{sup TM}]. Dose comparisons were performed using state-of-the-art MC codes for radiation transport, including ALGEBRA, BrachyDose, GEANT4, MCNP5, MCNP6, and PENELOPE2008. The methodologies adhered to recommendations in the AAPM TG-229 report on high-energy brachytherapy source dosimetry. TG-43 dosimetry parameters, an along-away dose-rate table, and primary and scatter separated (PSS) data were obtained. The virtual water phantom of (201){sup 3} voxels (1 mm sides) was used to evaluate the calculated dose distributions. Two test case plans involving a single position of the generic HDR {sup 192}Ir source in this phantom were prepared: (i) source centered in the phantom and (ii) source displaced 7 cm laterally from the center. Datasets were independently produced by different investigators. MC results were then compared against dose calculated using TG-43 and MBDCA methods. Results: TG-43 and PSS datasets were generated for the generic source, the PSS data for use with the ACE algorithm. The dose-rate constant values obtained from seven MC simulations, performed independently using different codes, were in excellent agreement, yielding an average of 1.1109 ± 0.0004 cGy/(h U) (k = 1, Type A uncertainty). MC calculated dose-rate distributions for the two plans were also found to be in excellent agreement, with differences within type A uncertainties. Differences between commercial MBDCA and MC results were test, position, and calculation parameter dependent. On average, however, these differences were within 1% for ACUROS and 2% for ACE at clinically relevant distances. Conclusions: A hypothetical, generic HDR {sup 192}Ir source was designed and implemented in two commercially available TPSs employing different MBDCAs. Reference dose distributions for this source were benchmarked and used for the evaluation of MBDCA calculations employing a virtual, cubic water phantom in the form of a CT DICOM image series. The implementation of a generic source of identical design in all TPSs using MBDCAs is an important step toward supporting univocal commissioning procedures and direct comparisons between TPSs.« less

Monte Carlo calculated microdosimetric spread for cell nucleus-sized targets exposed to brachytherapy 125I and 192Ir sources and 60Co cell irradiation.

PubMed

Villegas, Fernanda; Tilly, Nina; Ahnesjö, Anders

2013-09-07

The stochastic nature of ionizing radiation interactions causes a microdosimetric spread in energy depositions for cell or cell nucleus-sized volumes. The magnitude of the spread may be a confounding factor in dose response analysis. The aim of this work is to give values for the microdosimetric spread for a range of doses imparted by (125)I and (192)Ir brachytherapy radionuclides, and for a (60)Co source. An upgraded version of the Monte Carlo code PENELOPE was used to obtain frequency distributions of specific energy for each of these radiation qualities and for four different cell nucleus-sized volumes. The results demonstrate that the magnitude of the microdosimetric spread increases when the target size decreases or when the energy of the radiation quality is reduced. Frequency distributions calculated according to the formalism of Kellerer and Chmelevsky using full convolution of the Monte Carlo calculated single track frequency distributions confirm that at doses exceeding 0.08 Gy for (125)I, 0.1 Gy for (192)Ir, and 0.2 Gy for (60)Co, the resulting distribution can be accurately approximated with a normal distribution. A parameterization of the width of the distribution as a function of dose and target volume of interest is presented as a convenient form for the use in response modelling or similar contexts.

Data compression for satellite images

NASA Technical Reports Server (NTRS)

Chen, P. H.; Wintz, P. A.

1976-01-01

An efficient data compression system is presented for satellite pictures and two grey level pictures derived from satellite pictures. The compression techniques take advantages of the correlation between adjacent picture elements. Several source coding methods are investigated. Double delta coding is presented and shown to be the most efficient. Both predictive differential quantizing technique and double delta coding can be significantly improved by applying a background skipping technique. An extension code is constructed. This code requires very little storage space and operates efficiently. Simulation results are presented for various coding schemes and source codes.

The Newick utilities: high-throughput phylogenetic tree processing in the UNIX shell.

PubMed

Junier, Thomas; Zdobnov, Evgeny M

2010-07-01

We present a suite of Unix shell programs for processing any number of phylogenetic trees of any size. They perform frequently-used tree operations without requiring user interaction. They also allow tree drawing as scalable vector graphics (SVG), suitable for high-quality presentations and further editing, and as ASCII graphics for command-line inspection. As an example we include an implementation of bootscanning, a procedure for finding recombination breakpoints in viral genomes. C source code, Python bindings and executables for various platforms are available from http://cegg.unige.ch/newick_utils. The distribution includes a manual and example data. The package is distributed under the BSD License. thomas.junier@unige.ch

State-Chart Autocoder

NASA Technical Reports Server (NTRS)

Clark, Kenneth; Watney, Garth; Murray, Alexander; Benowitz, Edward

2007-01-01

A computer program translates Unified Modeling Language (UML) representations of state charts into source code in the C, C++, and Python computing languages. ( State charts signifies graphical descriptions of states and state transitions of a spacecraft or other complex system.) The UML representations constituting the input to this program are generated by using a UML-compliant graphical design program to draw the state charts. The generated source code is consistent with the "quantum programming" approach, which is so named because it involves discrete states and state transitions that have features in common with states and state transitions in quantum mechanics. Quantum programming enables efficient implementation of state charts, suitable for real-time embedded flight software. In addition to source code, the autocoder program generates a graphical-user-interface (GUI) program that, in turn, generates a display of state transitions in response to events triggered by the user. The GUI program is wrapped around, and can be used to exercise the state-chart behavior of, the generated source code. Once the expected state-chart behavior is confirmed, the generated source code can be augmented with a software interface to the rest of the software with which the source code is required to interact.

Practices in source code sharing in astrophysics

NASA Astrophysics Data System (ADS)

Shamir, Lior; Wallin, John F.; Allen, Alice; Berriman, Bruce; Teuben, Peter; Nemiroff, Robert J.; Mink, Jessica; Hanisch, Robert J.; DuPrie, Kimberly

2013-02-01

While software and algorithms have become increasingly important in astronomy, the majority of authors who publish computational astronomy research do not share the source code they develop, making it difficult to replicate and reuse the work. In this paper we discuss the importance of sharing scientific source code with the entire astrophysics community, and propose that journals require authors to make their code publicly available when a paper is published. That is, we suggest that a paper that involves a computer program not be accepted for publication unless the source code becomes publicly available. The adoption of such a policy by editors, editorial boards, and reviewers will improve the ability to replicate scientific results, and will also make computational astronomy methods more available to other researchers who wish to apply them to their data.

Gas bremsstrahlung shielding calculation for first optic enclosure of ILSF medical beamline

NASA Astrophysics Data System (ADS)

Beigzadeh Jalali, H.; Salimi, E.; Rahighi, J.

2016-10-01

Gas bremsstrahlung is generated in high energy electron storage ring accompanies the synchrotron radiation into the beamlines and strike the various components of the beamline. In this paper, radiation shielding calculation for secondary gas bremsstrahlung is performed for the first optics enclosure (FOE) of medical beamline of the Iranian Light Source Facility (ILSF). Dose equivalent rate (DER) calculation is accomplished using FLUKA Monte Carlo code. A comprehensive study of DER distribution at the back wall, sides and roof is given.

National Guard Logistics (NGLOG) Study

DTIC Science & Technology

1989-05-01

ROCiRE.ME-., NSTRUiMENr, DE ,’TrF CA7:0.%,JU’,BEZ ORGANIZATION (dfappiicaolei National Guard Bureau NGB-ARL 8C ADDRESS (City, State. inc ZI Code) 𔃺 SOURCE...which is accounted for by the USPFO of a state. This property can be distributed inter - and intrastate and redistributed without permission of any...reuimesso to upae then C-aigs, Stfor equipment funhes (Ea ofy uts within thean An. Not:l incositAenc betweenSA) dAOCentin interates handsutoaned rethatA which

UTM: Universal Transit Modeller

NASA Astrophysics Data System (ADS)

Deeg, Hans J.

2014-12-01

The Universal Transit Modeller (UTM) is a light-curve simulator for all kinds of transiting or eclipsing configurations between arbitrary numbers of several types of objects, which may be stars, planets, planetary moons, and planetary rings. A separate fitting program, UFIT (Universal Fitter) is part of the UTM distribution and may be used to derive best fits to light-curves for any set of continuously variable parameters. UTM/UFIT is written in IDL code and its source is released in the public domain under the GNU General Public License.

The WFIRST Galaxy Survey Exposure Time Calculator

NASA Technical Reports Server (NTRS)

Hirata, Christopher M.; Gehrels, Neil; Kneib, Jean-Paul; Kruk, Jeffrey; Rhodes, Jason; Wang, Yun; Zoubian, Julien

2013-01-01

This document describes the exposure time calculator for the Wide-Field Infrared Survey Telescope (WFIRST) high-latitude survey. The calculator works in both imaging and spectroscopic modes. In addition to the standard ETC functions (e.g. background and SN determination), the calculator integrates over the galaxy population and forecasts the density and redshift distribution of galaxy shapes usable for weak lensing (in imaging mode) and the detected emission lines (in spectroscopic mode). The source code is made available for public use.

Factor information retrieval system version 2. 0 (fire) (for microcomputers). Software

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

FIRE Version 2.0 contains EPA's unique recommended criteria and toxic air emission estimation factors. FIRE consists of: (1) an EPA internal repository system that contains emission factor data identified and collected, and (2) an external distribution system that contains only EPA's recommended factors. The emission factors, compiled from a review of the literature, are identified by pollutant name, CAS number, process and emission source descriptions, SIC code, SCC, and control status. The factors are rated for quality using AP-42 rating criteria.

Calculated Research on the Energetic Characteristic of TN in Composite Solid Propellant,

DTIC Science & Technology

1986-01-06

TEST CHART NATK)AAL BIREAU Of SIANDARN D %3 A F..• ,*’" ..... . . . L,.•...... . . . . . . . . FTD-ID(RS)T-0905-85 (0 FOREIGN TECHNOLOGY DIVISION...English pages: 12 Source: Yuhang Xuebao, Nr. 2, 1984, pp. 84-90 Country of origin: China Translated by: SCITRAN F33657-84- D -0165 Requester: FTD/TQTA...best quality copy available. Accesston 7i VTIS GT A&l DTIC TAB justif i,,Lltion- Distr-ibution/ Availability Codes Avail and/or D i t Special ft

The AMIDAS Website: An Online Tool for Direct Dark Matter Detection Experiments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shan, Chung-Lin

2010-02-10

Following our long-erm work on development of model-independent data analysis methods for reconstructing the one-dimensional velocity distribution function of halo WIMPs as well as for determining their mass and couplings on nucleons by using data from direct Dark Matter detection experiments directly, we combined the simulation programs to a compact system: AMIDAS (A Model-Independent Data Analysis System). For users' convenience an online system has also been established at the same time. AMIDAS has the ability to do full Monte Carlo simulations, faster theoretical estimations, as well as to analyze (real) data sets recorded in direct detection experiments without modifying themore » source code. In this article, I give an overview of functions of the AMIDAS code based on the use of its website.« less

Soft-Input Soft-Output Modules for the Construction and Distributed Iterative Decoding of Code Networks

NASA Technical Reports Server (NTRS)

Benedetto, S.; Divsalar, D.; Montorsi, G.; Pollara, F.

1998-01-01

Soft-input soft-output building blocks (modules) are presented to construct and iteratively decode in a distributed fashion code networks, a new concept that includes, and generalizes, various forms of concatenated coding schemes.

W-026, Waste Receiving and Processing Facility data management system validation and verification report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Palmer, M.E.

1997-12-05

This V and V Report includes analysis of two revisions of the DMS [data management system] System Requirements Specification (SRS) and the Preliminary System Design Document (PSDD); the source code for the DMS Communication Module (DMSCOM) messages; the source code for selected DMS Screens, and the code for the BWAS Simulator. BDM Federal analysts used a series of matrices to: compare the requirements in the System Requirements Specification (SRS) to the specifications found in the System Design Document (SDD), to ensure the design supports the business functions, compare the discreet parts of the SDD with each other, to ensure thatmore » the design is consistent and cohesive, compare the source code of the DMS Communication Module with the specifications, to ensure that the resultant messages will support the design, compare the source code of selected screens to the specifications to ensure that resultant system screens will support the design, compare the source code of the BWAS simulator with the requirements to interface with DMS messages and data transfers relating to the BWAS operations.« less

Fast-ion D(alpha) measurements and simulations in DIII-D

NASA Astrophysics Data System (ADS)

Luo, Yadong

The fast-ion Dalpha diagnostic measures the Doppler-shifted Dalpha light emitted by neutralized fast ions. For a favorable viewing geometry, the bright interferences from beam neutrals, halo neutrals, and edge neutrals span over a small wavelength range around the Dalpha rest wavelength and are blocked by a vertical bar at the exit focal plane of the spectrometer. Background subtraction and fitting techniques eliminate various contaminants in the spectrum. Fast-ion data are acquired with a time evolution of ˜1 ms, spatial resolution of ˜5 cm, and energy resolution of ˜10 keV. A weighted Monte Carlo simulation code models the fast-ion Dalpha spectra based on the fast-ion distribution function from other sources. In quiet plasmas, the spectral shape is in excellent agreement and absolute magnitude also has reasonable agreement. The fast-ion D alpha signal has the expected dependencies on plasma and neutral beam parameters. The neutral particle diagnostic and neutron diagnostic corroborate the fast-ion Dalpha measurements. The relative spatial profile is in agreement with the simulated profile based on the fast-ion distribution function from the TRANSP analysis code. During ion cyclotron heating, fast ions with high perpendicular energy are accelerated, while those with low perpendicular energy are barely affected. The spatial profile is compared with the simulated profiles based on the fast-ion distribution functions from the CQL Fokker-Planck code. In discharges with Alfven instabilities, both the spatial profile and spectral shape suggests that fast ions are redistributed. The flattened fast-ion Dalpha profile is in agreement with the fast-ion pressure profile.

The Fireball integrated code package

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dobranich, D.; Powers, D.A.; Harper, F.T.

1997-07-01

Many deep-space satellites contain a plutonium heat source. An explosion, during launch, of a rocket carrying such a satellite offers the potential for the release of some of the plutonium. The fireball following such an explosion exposes any released plutonium to a high-temperature chemically-reactive environment. Vaporization, condensation, and agglomeration processes can alter the distribution of plutonium-bearing particles. The Fireball code package simulates the integrated response of the physical and chemical processes occurring in a fireball and the effect these processes have on the plutonium-bearing particle distribution. This integrated treatment of multiple phenomena represents a significant improvement in the state ofmore » the art for fireball simulations. Preliminary simulations of launch-second scenarios indicate: (1) most plutonium vaporization occurs within the first second of the fireball; (2) large non-aerosol-sized particles contribute very little to plutonium vapor production; (3) vaporization and both homogeneous and heterogeneous condensation occur simultaneously; (4) homogeneous condensation transports plutonium down to the smallest-particle sizes; (5) heterogeneous condensation precludes homogeneous condensation if sufficient condensation sites are available; and (6) agglomeration produces larger-sized particles but slows rapidly as the fireball grows.« less

Transmission from theory to practice: Experiences using open-source code development and a virtual short course to increase the adoption of new theoretical approaches

NASA Astrophysics Data System (ADS)

Harman, C. J.

2015-12-01

Even amongst the academic community, new theoretical tools can remain underutilized due to the investment of time and resources required to understand and implement them. This surely limits the frequency that new theory is rigorously tested against data by scientists outside the group that developed it, and limits the impact that new tools could have on the advancement of science. Reducing the barriers to adoption through online education and open-source code can bridge the gap between theory and data, forging new collaborations, and advancing science. A pilot venture aimed at increasing the adoption of a new theory of time-variable transit time distributions was begun in July 2015 as a collaboration between Johns Hopkins University and The Consortium of Universities for the Advancement of Hydrologic Science (CUAHSI). There were four main components to the venture: a public online seminar covering the theory, an open source code repository, a virtual short course designed to help participants apply the theory to their data, and an online forum to maintain discussion and build a community of users. 18 participants were selected for the non-public components based on their responses in an application, and were asked to fill out a course evaluation at the end of the short course, and again several months later. These evaluations, along with participation in the forum and on-going contact with the organizer suggest strengths and weaknesses in this combination of components to assist participants in adopting new tools.

Bidirectional tornado modes on the Joint European Torus

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sandquist, P.; Sharapov, S. E.; Lisak, M.

In discharges on the Joint European Torus [P. H. Rebut and B. E. Keen, Fusion Technol. 11, 13 (1987)] with safety factor q(0)<1 and high-power ion cyclotron resonance heating (ICRH), monster sawtooth crashes are preceded by frequency sweeping 'tornado modes' in the toroidal Alfven eigenmode frequency range. A suite of equilibrium and spectral magnetohydrodynamical codes is used for explaining the observed evolution of the tornado mode frequency and for identifying temporal evolution of the safety factor inside the q=1 radius just before sawtooth crashes. In some cases, the tornado modes are observed simultaneously with both positive and negative toroidal modemore » numbers. Hence, a free energy source other than the radial gradient of the energetic ion pressure exciting these modes is sought. The distribution function of the ICRH-accelerated ions is assessed with the SELFO code [J. Hedin et al., Nucl. Fusion 42, 527 (2002)] and energetic particle drive due to the velocity space anisotropy of ICRH-accelerated ions is considered analytically as the possible source for excitation of bidirectional tornado modes.« less

Enhancing participatory approach in water resources management: development of a survey to evaluate stakeholders needs and priorities related to software capabilities

NASA Astrophysics Data System (ADS)

Foglia, L.; Rossetto, R.; Borsi, I.; Josef, S.; Boukalova, Z.; Triana, F.; Ghetta, M.; Sabbatini, T.; Bonari, E.; Cannata, M.; De Filippis, G.

2016-12-01

The EU H2020 FREEWAT project (FREE and open source software tools for WATer resource management) aims at simplifying the application of EU-water related Directives, by developing an open source and public domain, GIS-integrated platform for planning and management of ground- and surface-water resources. The FREEWAT platform is conceived as a canvas, where several distributed and physically-based simulation codes are virtually integrated. The choice of such codes was supported by the result of a survey performed by means of questionnaires distributed to 14 case study FREEWAT project partners and several stakeholders. This was performed in the first phase of the project within the WP 6 (Enhanced science and participatory approach evidence-based decision making), Task 6.1 (Definition of a "needs/tools" evaluation grid). About 30% among all the invited entities and institutions from several EU and non-EU Countries expressed their interest in contributing to the survey. Most of them were research institutions, government and geoenvironmental companies and river basin authorities.The result of the questionnaire provided a spectrum of needs and priorities of partners/stakeholders, which were addressed during the development phase of the FREEWAT platform. The main needs identified were related to ground- and surface-water quality, sustainable water management, interaction between groundwater/surface-water bodies, and design and management of Managed Aquifer Recharge schemes. Needs and priorities were then connected to the specific EU Directives and Regulations to be addressed.One of the main goals of the questionnaires was to collect information and suggestions regarding the use of existing commercial/open-source software tools to address needs and priorities, and regarding the needs to address specific water-related processes/problems.

Authorship attribution of source code by using back propagation neural network based on particle swarm optimization

PubMed Central

Xu, Guoai; Li, Qi; Guo, Yanhui; Zhang, Miao

2017-01-01

Authorship attribution is to identify the most likely author of a given sample among a set of candidate known authors. It can be not only applied to discover the original author of plain text, such as novels, blogs, emails, posts etc., but also used to identify source code programmers. Authorship attribution of source code is required in diverse applications, ranging from malicious code tracking to solving authorship dispute or software plagiarism detection. This paper aims to propose a new method to identify the programmer of Java source code samples with a higher accuracy. To this end, it first introduces back propagation (BP) neural network based on particle swarm optimization (PSO) into authorship attribution of source code. It begins by computing a set of defined feature metrics, including lexical and layout metrics, structure and syntax metrics, totally 19 dimensions. Then these metrics are input to neural network for supervised learning, the weights of which are output by PSO and BP hybrid algorithm. The effectiveness of the proposed method is evaluated on a collected dataset with 3,022 Java files belong to 40 authors. Experiment results show that the proposed method achieves 91.060% accuracy. And a comparison with previous work on authorship attribution of source code for Java language illustrates that this proposed method outperforms others overall, also with an acceptable overhead. PMID:29095934

The mathematical theory of signal processing and compression-designs

NASA Astrophysics Data System (ADS)

Feria, Erlan H.

2006-05-01

The mathematical theory of signal processing, named processor coding, will be shown to inherently arise as the computational time dual of Shannon's mathematical theory of communication which is also known as source coding. Source coding is concerned with signal source memory space compression while processor coding deals with signal processor computational time compression. Their combination is named compression-designs and referred as Conde in short. A compelling and pedagogically appealing diagram will be discussed highlighting Conde's remarkable successful application to real-world knowledge-aided (KA) airborne moving target indicator (AMTI) radar.

Accurate Modeling of Ionospheric Electromagnetic Fields Generated by a Low-Altitude VLF Transmitter

DTIC Science & Technology

2007-08-31

latitude) for 3 different grid spacings. 14 8. Low-altitude fields produced by a 10-kHz source computed using the FD and TD codes. The agreement is...excellent, validating the new FD code. 16 9. High-altitude fields produced by a 10-kHz source computed using the FD and TD codes. The agreement is...again excellent. 17 10. Low-altitude fields produced by a 20-k.Hz source computed using the FD and TD codes. 17 11. High-altitude fields produced

A molecular dynamics implementation of the 3D Mercedes-Benz water model

NASA Astrophysics Data System (ADS)

Hynninen, T.; Dias, C. L.; Mkrtchyan, A.; Heinonen, V.; Karttunen, M.; Foster, A. S.; Ala-Nissila, T.

2012-02-01

The three-dimensional Mercedes-Benz model was recently introduced to account for the structural and thermodynamic properties of water. It treats water molecules as point-like particles with four dangling bonds in tetrahedral coordination, representing H-bonds of water. Its conceptual simplicity renders the model attractive in studies where complex behaviors emerge from H-bond interactions in water, e.g., the hydrophobic effect. A molecular dynamics (MD) implementation of the model is non-trivial and we outline here the mathematical framework of its force-field. Useful routines written in modern Fortran are also provided. This open source code is free and can easily be modified to account for different physical context. The provided code allows both serial and MPI-parallelized execution. Program summaryProgram title: CASHEW (Coarse Approach Simulator for Hydrogen-bonding Effects in Water) Catalogue identifier: AEKM_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEKM_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 20 501 No. of bytes in distributed program, including test data, etc.: 551 044 Distribution format: tar.gz Programming language: Fortran 90 Computer: Program has been tested on desktop workstations and a Cray XT4/XT5 supercomputer. Operating system: Linux, Unix, OS X Has the code been vectorized or parallelized?: The code has been parallelized using MPI. RAM: Depends on size of system, about 5 MB for 1500 molecules. Classification: 7.7 External routines: A random number generator, Mersenne Twister ( http://www.math.sci.hiroshima-u.ac.jp/m-mat/MT/VERSIONS/FORTRAN/mt95.f90), is used. A copy of the code is included in the distribution. Nature of problem: Molecular dynamics simulation of a new geometric water model. Solution method: New force-field for water molecules, velocity-Verlet integration, representation of molecules as rigid particles with rotations described using quaternion algebra. Restrictions: Memory and cpu time limit the size of simulations. Additional comments: Software web site: https://gitorious.org/cashew/. Running time: Depends on the size of system. The sample tests provided only take a few seconds.

Three-dimensional fuel pin model validation by prediction of hydrogen distribution in cladding and comparison with experiment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aly, A.; Avramova, Maria; Ivanov, Kostadin

To correctly describe and predict this hydrogen distribution there is a need for multi-physics coupling to provide accurate three-dimensional azimuthal, radial, and axial temperature distributions in the cladding. Coupled high-fidelity reactor-physics codes with a sub-channel code as well as with a computational fluid dynamics (CFD) tool have been used to calculate detailed temperature distributions. These high-fidelity coupled neutronics/thermal-hydraulics code systems are coupled further with the fuel-performance BISON code with a kernel (module) for hydrogen. Both hydrogen migration and precipitation/dissolution are included in the model. Results from this multi-physics analysis is validated utilizing calculations of hydrogen distribution using models informed bymore » data from hydrogen experiments and PIE data.« less

Comparing the contributions of ionospheric outflow and high-altitude production to O+ loss at Mars

NASA Astrophysics Data System (ADS)

Liemohn, Michael; Curry, Shannon; Fang, Xiaohua; Johnson, Blake; Fraenz, Markus; Ma, Yingjuan

2013-04-01

The Mars total O+ escape rate is highly dependent on both the ionospheric and high-altitude source terms. Because of their different source locations, they appear in velocity space distributions as distinct populations. The Mars Test Particle model is used (with background parameters from the BATS-R-US magnetohydrodynamic code) to simulate the transport of ions in the near-Mars space environment. Because it is a collisionless model, the MTP's inner boundary is placed at 300 km altitude for this study. The MHD values at this altitude are used to define an ionospheric outflow source of ions for the MTP. The resulting loss distributions (in both real and velocity space) from this ionospheric source term are compared against those from high-altitude ionization mechanisms, in particular photoionization, charge exchange, and electron impact ionization, each of which have their own (albeit overlapping) source regions. In subsequent simulations, the MHD values defining the ionospheric outflow are systematically varied to parametrically explore possible ionospheric outflow scenarios. For the nominal MHD ionospheric outflow settings, this source contributes only 10% to the total O+ loss rate, nearly all via the central tail region. There is very little dependence of this percentage on the initial temperature, but a change in the initial density or bulk velocity directly alters this loss through the central tail. However, a density or bulk velocity increase of a factor of 10 makes the ionospheric outflow loss comparable in magnitude to the loss from the combined high-altitude sources. The spatial and velocity space distributions of escaping O+ are examined and compared for the various source terms, identifying features specific to each ion source mechanism. These results are applied to a specific Mars Express orbit and used to interpret high-altitude observations from the ion mass analyzer onboard MEX.

A simulation-based analytic model of radio galaxies

NASA Astrophysics Data System (ADS)

Hardcastle, M. J.

2018-04-01

I derive and discuss a simple semi-analytical model of the evolution of powerful radio galaxies which is not based on assumptions of self-similar growth, but rather implements some insights about the dynamics and energetics of these systems derived from numerical simulations, and can be applied to arbitrary pressure/density profiles of the host environment. The model can qualitatively and quantitatively reproduce the source dynamics and synchrotron light curves derived from numerical modelling. Approximate corrections for radiative and adiabatic losses allow it to predict the evolution of radio spectral index and of inverse-Compton emission both for active and `remnant' sources after the jet has turned off. Code to implement the model is publicly available. Using a standard model with a light relativistic (electron-positron) jet, subequipartition magnetic fields, and a range of realistic group/cluster environments, I simulate populations of sources and show that the model can reproduce the range of properties of powerful radio sources as well as observed trends in the relationship between jet power and radio luminosity, and predicts their dependence on redshift and environment. I show that the distribution of source lifetimes has a significant effect on both the source length distribution and the fraction of remnant sources expected in observations, and so can in principle be constrained by observations. The remnant fraction is expected to be low even at low redshift and low observing frequency due to the rapid luminosity evolution of remnants, and to tend rapidly to zero at high redshift due to inverse-Compton losses.

A geo-coded inventory of anophelines in the Afrotropical Region south of the Sahara: 1898-2016.

PubMed

Kyalo, David; Amratia, Punam; Mundia, Clara W; Mbogo, Charles M; Coetzee, Maureen; Snow, Robert W

2017-01-01

Background : Understanding the distribution of anopheline vectors of malaria is an important prelude to the design of national malaria control and elimination programmes. A single, geo-coded continental inventory of anophelines using all available published and unpublished data has not been undertaken since the 1960s. Methods : We have searched African, European and World Health Organization archives to identify unpublished reports on anopheline surveys in 48 sub-Saharan Africa countries. This search was supplemented by identification of reports that formed part of post-graduate theses, conference abstracts, regional insecticide resistance databases and more traditional bibliographic searches of peer-reviewed literature. Finally, a check was made against two recent repositories of dominant malaria vector species locations ( circa 2,500). Each report was used to extract information on the survey dates, village locations (geo-coded to provide a longitude and latitude), sampling methods, species identification methods and all anopheline species found present during the survey. Survey records were collapsed to a single site over time.    Results : The search strategy took years and resulted in 13,331 unique, geo-coded survey locations of anopheline vector occurrence between 1898 and 2016. A total of 12,204 (92%) sites reported the presence of 10 dominant vector species/sibling species; 4,473 (37%) of these sites were sampled since 2005. 4,442 (33%) sites reported at least one of 13 possible secondary vector species; 1,107 (25%) of these sites were sampled since 2005. Distributions of dominant and secondary vectors conform to previous descriptions of the ecological ranges of these vectors. Conclusion : We have assembled the largest ever geo-coded database of anophelines in Africa, representing a legacy dataset for future updating and identification of knowledge gaps at national levels. The geo-coded database is available on Harvard Dataverse as a reference source for African national malaria control programmes planning their future control and elimination strategies.

A geo-coded inventory of anophelines in the Afrotropical Region south of the Sahara: 1898-2016

PubMed Central

Kyalo, David; Amratia, Punam; Mundia, Clara W.; Mbogo, Charles M.; Coetzee, Maureen; Snow, Robert W.

2017-01-01

Background: Understanding the distribution of anopheline vectors of malaria is an important prelude to the design of national malaria control and elimination programmes. A single, geo-coded continental inventory of anophelines using all available published and unpublished data has not been undertaken since the 1960s. Methods: We have searched African, European and World Health Organization archives to identify unpublished reports on anopheline surveys in 48 sub-Saharan Africa countries. This search was supplemented by identification of reports that formed part of post-graduate theses, conference abstracts, regional insecticide resistance databases and more traditional bibliographic searches of peer-reviewed literature. Finally, a check was made against two recent repositories of dominant malaria vector species locations ( circa 2,500). Each report was used to extract information on the survey dates, village locations (geo-coded to provide a longitude and latitude), sampling methods, species identification methods and all anopheline species found present during the survey. Survey records were collapsed to a single site over time.    Results: The search strategy took years and resulted in 13,331 unique, geo-coded survey locations of anopheline vector occurrence between 1898 and 2016. A total of 12,204 (92%) sites reported the presence of 10 dominant vector species/sibling species; 4,473 (37%) of these sites were sampled since 2005. 4,442 (33%) sites reported at least one of 13 possible secondary vector species; 1,107 (25%) of these sites were sampled since 2005. Distributions of dominant and secondary vectors conform to previous descriptions of the ecological ranges of these vectors. Conclusion: We have assembled the largest ever geo-coded database of anophelines in Africa, representing a legacy dataset for future updating and identification of knowledge gaps at national levels. The geo-coded database is available on Harvard Dataverse as a reference source for African national malaria control programmes planning their future control and elimination strategies. PMID:28884158

Review of Hybrid (Deterministic/Monte Carlo) Radiation Transport Methods, Codes, and Applications at Oak Ridge National Laboratory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wagner, John C; Peplow, Douglas E.; Mosher, Scott W

2010-01-01

This paper provides a review of the hybrid (Monte Carlo/deterministic) radiation transport methods and codes used at the Oak Ridge National Laboratory and examples of their application for increasing the efficiency of real-world, fixed-source Monte Carlo analyses. The two principal hybrid methods are (1) Consistent Adjoint Driven Importance Sampling (CADIS) for optimization of a localized detector (tally) region (e.g., flux, dose, or reaction rate at a particular location) and (2) Forward Weighted CADIS (FW-CADIS) for optimizing distributions (e.g., mesh tallies over all or part of the problem space) or multiple localized detector regions (e.g., simultaneous optimization of two or moremore » localized tally regions). The two methods have been implemented and automated in both the MAVRIC sequence of SCALE 6 and ADVANTG, a code that works with the MCNP code. As implemented, the methods utilize the results of approximate, fast-running 3-D discrete ordinates transport calculations (with the Denovo code) to generate consistent space- and energy-dependent source and transport (weight windows) biasing parameters. These methods and codes have been applied to many relevant and challenging problems, including calculations of PWR ex-core thermal detector response, dose rates throughout an entire PWR facility, site boundary dose from arrays of commercial spent fuel storage casks, radiation fields for criticality accident alarm system placement, and detector response for special nuclear material detection scenarios and nuclear well-logging tools. Substantial computational speed-ups, generally O(10{sup 2-4}), have been realized for all applications to date. This paper provides a brief review of the methods, their implementation, results of their application, and current development activities, as well as a considerable list of references for readers seeking more information about the methods and/or their applications.« less

Accelerate Implementation of the WHO Global Code of Practice on International Recruitment of Health Personnel: Experiences From the South East Asia Region

PubMed Central

Tangcharoensathien, Viroj; Travis, Phyllida

2016-01-01

Strengthening the health workforce and universal health coverage (UHC) are among key targets in the heath-related Sustainable Development Goals (SDGs) to be committed by the United Nations (UN) Member States in September 2015. The health workforce, the backbone of health systems, contributes to functioning delivery systems. Equitable distribution of functioning services is indispensable to achieve one of the UHC goals of equitable access. This commentary argues the World Health Organization (WHO) Global Code of Practice on International Recruitment of Health Personnel is relevant to the countries in the South East Asia Region (SEAR) as there is a significant outflow of health workers from several countries and a significant inflow in a few, increased demand for health workforce in high- and middle-income countries, and slow progress in addressing the "push factors." Awareness and implementation of the Code in the first report in 2012 was low but significantly improved in the second report in 2015. An inter-country workshop in 2015 convened by WHO SEAR to review progress in implementation of the Code was an opportunity for countries to share lessons on policy implementation, on retention of health workers, scaling up health professional education and managing in and out migration. The meeting noted that capturing outmigration of health personnel, which is notoriously difficult for source countries, is possible where there is an active recruitment management through government to government (G to G) contracts or licensing the recruiters and mandatory reporting requirement by them. According to the 2015 second report on the Code, the size and profile of outflow health workers from SEAR source countries is being captured and now also increasingly being shared by destination country professional councils. This is critical information to foster policy action and implementation of the Code in the Region. PMID:26673648

Review of particle-in-cell modeling for the extraction region of large negative hydrogen ion sources for fusion

NASA Astrophysics Data System (ADS)

Wünderlich, D.; Mochalskyy, S.; Montellano, I. M.; Revel, A.

2018-05-01

Particle-in-cell (PIC) codes are used since the early 1960s for calculating self-consistently the motion of charged particles in plasmas, taking into account external electric and magnetic fields as well as the fields created by the particles itself. Due to the used very small time steps (in the order of the inverse plasma frequency) and mesh size, the computational requirements can be very high and they drastically increase with increasing plasma density and size of the calculation domain. Thus, usually small computational domains and/or reduced dimensionality are used. In the last years, the available central processing unit (CPU) power strongly increased. Together with a massive parallelization of the codes, it is now possible to describe in 3D the extraction of charged particles from a plasma, using calculation domains with an edge length of several centimeters, consisting of one extraction aperture, the plasma in direct vicinity of the aperture, and a part of the extraction system. Large negative hydrogen or deuterium ion sources are essential parts of the neutral beam injection (NBI) system in future fusion devices like the international fusion experiment ITER and the demonstration reactor (DEMO). For ITER NBI RF driven sources with a source area of 0.9 × 1.9 m2 and 1280 extraction apertures will be used. The extraction of negative ions is accompanied by the co-extraction of electrons which are deflected onto an electron dump. Typically, the maximum negative extracted ion current is limited by the amount and the temporal instability of the co-extracted electrons, especially for operation in deuterium. Different PIC codes are available for the extraction region of large driven negative ion sources for fusion. Additionally, some effort is ongoing in developing codes that describe in a simplified manner (coarser mesh or reduced dimensionality) the plasma of the whole ion source. The presentation first gives a brief overview of the current status of the ion source development for ITER NBI and of the PIC method. Different PIC codes for the extraction region are introduced as well as the coupling to codes describing the whole source (PIC codes or fluid codes). Presented and discussed are different physical and numerical aspects of applying PIC codes to negative hydrogen ion sources for fusion as well as selected code results. The main focus of future calculations will be the meniscus formation and identifying measures for reducing the co-extracted electrons, in particular for deuterium operation. The recent results of the 3D PIC code ONIX (calculation domain: one extraction aperture and its vicinity) for the ITER prototype source (1/8 size of the ITER NBI source) are presented.

Recent progress in distributed optical fiber Raman photon sensors at China Jiliang University

NASA Astrophysics Data System (ADS)

Zhang, Zaixuan; Wang, Jianfeng; Li, Yi; Gong, Huaping; Yu, Xiangdong; Liu, Honglin; Jin, Yongxing; Kang, Juan; Li, Chenxia; Zhang, Wensheng; Zhang, Wenping; Niu, Xiaohui; Sun, Zhongzhou; Zhao, Chunliu; Dong, Xinyong; Jin, Shangzhong

2012-06-01

A brief review of recent progress in researches, productions and applications of full distributed fiber Raman photon sensors at China Jiliang University (CJLU) is presented. In order to improve the measurement distance, the accuracy, the space resolution, the ability of multi-parameter measurements, and the intelligence of full distributed fiber sensor systems, a new generation fiber sensor technology based on the optical fiber nonlinear scattering fusion principle is proposed. A series of new generation full distributed fiber sensors are investigated and designed, which consist of new generation ultra-long distance full distributed fiber Raman and Rayleigh scattering photon sensors integrated with a fiber Raman amplifier, auto-correction full distributed fiber Raman photon temperature sensors based on Raman correlation dual sources, full distributed fiber Raman photon temperature sensors based on a pulse coding source, full distributed fiber Raman photon temperature sensors using a fiber Raman wavelength shifter, a new type of Brillouin optical time domain analyzers (BOTDAs) integrated with a fiber Raman amplifier for replacing a fiber Brillouin amplifier, full distributed fiber Raman and Brillouin photon sensors integrated with a fiber Raman amplifier, and full distributed fiber Brillouin photon sensors integrated with a fiber Brillouin frequency shifter. The Internet of things is believed as one of candidates of the next technological revolution, which has driven hundreds of millions of class markets. Sensor networks are important components of the Internet of things. The full distributed optical fiber sensor network (Rayleigh, Raman, and Brillouin scattering) is a 3S (smart materials, smart structure, and smart skill) system, which is easy to construct smart fiber sensor networks. The distributed optical fiber sensor can be embedded in the power grids, railways, bridges, tunnels, roads, constructions, water supply systems, dams, oil and gas pipelines and other facilities, and can be integrated with wireless networks.

A 2D forward and inverse code for streaming potential problems

NASA Astrophysics Data System (ADS)

Soueid Ahmed, A.; Jardani, A.; Revil, A.

2013-12-01

The self-potential method corresponds to the passive measurement of the electrical field in response to the occurrence of natural sources of current in the ground. One of these sources corresponds to the streaming current associated with the flow of the groundwater. We can therefore apply the self- potential method to recover non-intrusively some information regarding the groundwater flow. We first solve the forward problem starting with the solution of the groundwater flow problem, then computing the source current density, and finally solving a Poisson equation for the electrical potential. We use the finite-element method to solve the relevant partial differential equations. In order to reduce the number of (petrophysical) model parameters required to solve the forward problem, we introduced an effective charge density tensor of the pore water, which can be determined directly from the permeability tensor for neutral pore waters. The second aspect of our work concerns the inversion of the self-potential data using Tikhonov regularization with smoothness and weighting depth constraints. This approach accounts for the distribution of the electrical resistivity, which can be independently and approximately determined from electrical resistivity tomography. A numerical code, SP2DINV, has been implemented in Matlab to perform both the forward and inverse modeling. Three synthetic case studies are discussed.

The dependence of frequency distributions on multiple meanings of words, codes and signs

NASA Astrophysics Data System (ADS)

Yan, Xiaoyong; Minnhagen, Petter

2018-01-01

The dependence of the frequency distributions due to multiple meanings of words in a text is investigated by deleting letters. By coding the words with fewer letters the number of meanings per coded word increases. This increase is measured and used as an input in a predictive theory. For a text written in English, the word-frequency distribution is broad and fat-tailed, whereas if the words are only represented by their first letter the distribution becomes exponential. Both distribution are well predicted by the theory, as is the whole sequence obtained by consecutively representing the words by the first L = 6 , 5 , 4 , 3 , 2 , 1 letters. Comparisons of texts written by Chinese characters and the same texts written by letter-codes are made and the similarity of the corresponding frequency-distributions are interpreted as a consequence of the multiple meanings of Chinese characters. This further implies that the difference of the shape for word-frequencies for an English text written by letters and a Chinese text written by Chinese characters is due to the coding and not to the language per se.

Surveying multidisciplinary aspects in real-time distributed coding for Wireless Sensor Networks.

PubMed

Braccini, Carlo; Davoli, Franco; Marchese, Mario; Mongelli, Maurizio

2015-01-27

Wireless Sensor Networks (WSNs), where a multiplicity of sensors observe a physical phenomenon and transmit their measurements to one or more sinks, pertain to the class of multi-terminal source and channel coding problems of Information Theory. In this category, "real-time" coding is often encountered for WSNs, referring to the problem of finding the minimum distortion (according to a given measure), under transmission power constraints, attainable by encoding and decoding functions, with stringent limits on delay and complexity. On the other hand, the Decision Theory approach seeks to determine the optimal coding/decoding strategies or some of their structural properties. Since encoder(s) and decoder(s) possess different information, though sharing a common goal, the setting here is that of Team Decision Theory. A more pragmatic vision rooted in Signal Processing consists of fixing the form of the coding strategies (e.g., to linear functions) and, consequently, finding the corresponding optimal decoding strategies and the achievable distortion, generally by applying parametric optimization techniques. All approaches have a long history of past investigations and recent results. The goal of the present paper is to provide the taxonomy of the various formulations, a survey of the vast related literature, examples from the authors' own research, and some highlights on the inter-play of the different theories.

Real-time realizations of the Bayesian Infrasonic Source Localization Method

NASA Astrophysics Data System (ADS)

Pinsky, V.; Arrowsmith, S.; Hofstetter, A.; Nippress, A.

2015-12-01

The Bayesian Infrasonic Source Localization method (BISL), introduced by Mordak et al. (2010) and upgraded by Marcillo et al. (2014) is destined for the accurate estimation of the atmospheric event origin at local, regional and global scales by the seismic and infrasonic networks and arrays. The BISL is based on probabilistic models of the source-station infrasonic signal propagation time, picking time and azimuth estimate merged with a prior knowledge about celerity distribution. It requires at each hypothetical source location, integration of the product of the corresponding source-station likelihood functions multiplied by a prior probability density function of celerity over the multivariate parameter space. The present BISL realization is generally time-consuming procedure based on numerical integration. The computational scheme proposed simplifies the target function so that integrals are taken exactly and are represented via standard functions. This makes the procedure much faster and realizable in real-time without practical loss of accuracy. The procedure executed as PYTHON-FORTRAN code demonstrates high performance on a set of the model and real data.

Probabilistic accident consequence uncertainty analysis: Dispersion and deposition uncertainty assessment, appendices A and B

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harper, F.T.; Young, M.L.; Miller, L.A.

The development of two new probabilistic accident consequence codes, MACCS and COSYMA, completed in 1990, estimate the risks presented by nuclear installations based on postulated frequencies and magnitudes of potential accidents. In 1991, the US Nuclear Regulatory Commission (NRC) and the Commission of the European Communities (CEC) began a joint uncertainty analysis of the two codes. The objective was to develop credible and traceable uncertainty distributions for the input variables of the codes. Expert elicitation, developed independently, was identified as the best technology available for developing a library of uncertainty distributions for the selected consequence parameters. The study was formulatedmore » jointly and was limited to the current code models and to physical quantities that could be measured in experiments. To validate the distributions generated for the wet deposition input variables, samples were taken from these distributions and propagated through the wet deposition code model along with the Gaussian plume model (GPM) implemented in the MACCS and COSYMA codes. Resulting distributions closely replicated the aggregated elicited wet deposition distributions. Project teams from the NRC and CEC cooperated successfully to develop and implement a unified process for the elaboration of uncertainty distributions on consequence code input parameters. Formal expert judgment elicitation proved valuable for synthesizing the best available information. Distributions on measurable atmospheric dispersion and deposition parameters were successfully elicited from experts involved in the many phenomenological areas of consequence analysis. This volume is the second of a three-volume document describing the project and contains two appendices describing the rationales for the dispersion and deposition data along with short biographies of the 16 experts who participated in the project.« less

Conflict Containment in the Balkans: Testing Extended Deterrence.

DTIC Science & Technology

1995-03-01

STATEMENT 12b. DISTRIBUTION CODE Approved for public release; distribution is unlimited. 13. ABSTRACT This thesis critically analyzes a prominent theoretical...Containment 15. NUMBER OF in the Balkans; Deterrence; Coercive Diplomacy; Balance of Forces. PAGES: 161 16. PRICE CODE 17. SECURITY CLASSIFI- 18. SECURITY...Department of National Security Affai sAccesion For NTIS CRA&I DTtC TAB Unannounced Justifca ........... By- Distribution Availability Codes Avail and/or Dist

ITS Version 6 : the integrated TIGER series of coupled electron/photon Monte Carlo transport codes.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Franke, Brian Claude; Kensek, Ronald Patrick; Laub, Thomas William

2008-04-01

ITS is a powerful and user-friendly software package permitting state-of-the-art Monte Carlo solution of lineartime-independent coupled electron/photon radiation transport problems, with or without the presence of macroscopic electric and magnetic fields of arbitrary spatial dependence. Our goal has been to simultaneously maximize operational simplicity and physical accuracy. Through a set of preprocessor directives, the user selects one of the many ITS codes. The ease with which the makefile system is applied combines with an input scheme based on order-independent descriptive keywords that makes maximum use of defaults and internal error checking to provide experimentalists and theorists alike with a methodmore » for the routine but rigorous solution of sophisticated radiation transport problems. Physical rigor is provided by employing accurate cross sections, sampling distributions, and physical models for describing the production and transport of the electron/photon cascade from 1.0 GeV down to 1.0 keV. The availability of source code permits the more sophisticated user to tailor the codes to specific applications and to extend the capabilities of the codes to more complex applications. Version 6, the latest version of ITS, contains (1) improvements to the ITS 5.0 codes, and (2) conversion to Fortran 90. The general user friendliness of the software has been enhanced through memory allocation to reduce the need for users to modify and recompile the code.« less

The FORTRAN static source code analyzer program (SAP) system description

NASA Technical Reports Server (NTRS)

Decker, W.; Taylor, W.; Merwarth, P.; Oneill, M.; Goorevich, C.; Waligora, S.

1982-01-01

A source code analyzer program (SAP) designed to assist personnel in conducting studies of FORTRAN programs is described. The SAP scans FORTRAN source code and produces reports that present statistics and measures of statements and structures that make up a module. The processing performed by SAP and of the routines, COMMON blocks, and files used by SAP are described. The system generation procedure for SAP is also presented.

Benchmarking for Bayesian Reinforcement Learning

PubMed Central

Ernst, Damien; Couëtoux, Adrien

2016-01-01

In the Bayesian Reinforcement Learning (BRL) setting, agents try to maximise the collected rewards while interacting with their environment while using some prior knowledge that is accessed beforehand. Many BRL algorithms have already been proposed, but the benchmarks used to compare them are only relevant for specific cases. The paper addresses this problem, and provides a new BRL comparison methodology along with the corresponding open source library. In this methodology, a comparison criterion that measures the performance of algorithms on large sets of Markov Decision Processes (MDPs) drawn from some probability distributions is defined. In order to enable the comparison of non-anytime algorithms, our methodology also includes a detailed analysis of the computation time requirement of each algorithm. Our library is released with all source code and documentation: it includes three test problems, each of which has two different prior distributions, and seven state-of-the-art RL algorithms. Finally, our library is illustrated by comparing all the available algorithms and the results are discussed. PMID:27304891

Benchmarking for Bayesian Reinforcement Learning.

PubMed

Castronovo, Michael; Ernst, Damien; Couëtoux, Adrien; Fonteneau, Raphael

2016-01-01

In the Bayesian Reinforcement Learning (BRL) setting, agents try to maximise the collected rewards while interacting with their environment while using some prior knowledge that is accessed beforehand. Many BRL algorithms have already been proposed, but the benchmarks used to compare them are only relevant for specific cases. The paper addresses this problem, and provides a new BRL comparison methodology along with the corresponding open source library. In this methodology, a comparison criterion that measures the performance of algorithms on large sets of Markov Decision Processes (MDPs) drawn from some probability distributions is defined. In order to enable the comparison of non-anytime algorithms, our methodology also includes a detailed analysis of the computation time requirement of each algorithm. Our library is released with all source code and documentation: it includes three test problems, each of which has two different prior distributions, and seven state-of-the-art RL algorithms. Finally, our library is illustrated by comparing all the available algorithms and the results are discussed.

BSDWormer; an Open Source Implementation of a Poisson Wavelet Multiscale Analysis for Potential Fields

NASA Astrophysics Data System (ADS)

Horowitz, F. G.; Gaede, O.

2014-12-01

Wavelet multiscale edge analysis of potential fields (a.k.a. "worms") has been known since Moreau et al. (1997) and was independently derived by Hornby et al. (1999). The technique is useful for producing a scale-explicit overview of the structures beneath a gravity or magnetic survey, including establishing the location and estimating the attitude of surface features, as well as incorporating information about the geometric class (point, line, surface, volume, fractal) of the underlying sources — in a fashion much like traditional structural indices from Euler solutions albeit with better areal coverage. Hornby et al. (2002) show that worms form the locally highest concentration of horizontal edges of a given strike — which in conjunction with the results from Mallat and Zhong (1992) induces a (non-unique!) inversion where the worms are physically interpretable as lateral boundaries in a source distribution that produces a close approximation of the observed potential field. The technique has enjoyed widespread adoption and success in the Australian mineral exploration community — including "ground truth" via successfully drilling structures indicated by the worms. Unfortunately, to our knowledge, all implementations of the code to calculate the worms/multiscale edges (including Horowitz' original research code) are either part of commercial software packages, or have copyright restrictions that impede the use of the technique by the wider community. The technique is completely described mathematically in Hornby et al. (1999) along with some later publications. This enables us to re-implement from scratch the code required to calculate and visualize the worms. We are freely releasing the results under an (open source) BSD two-clause software license. A git repository is available at . We will give an overview of the technique, show code snippets using the codebase, and present visualization results for example datasets (including the Surat basin of Australia, and the Lake Ontario region of North America). We invite you to join us in creating and using the best worming software for potential fields in existence — as both gratis and libre software!

Nonuniformity of Temperatures in Microwave Steam Heating of Lobster Tail.

PubMed

Fleischman, Gregory J

2016-11-01

The biennial Conference for Food Protection provides a formal process for all interested parties to influence food safety guidance. At a recent conference, an issue was raised culminating in a formal request to the U.S. Food and Drug Administration to change its Food Code recommendation for safe cooking of seafood using microwave energy when steaming was also employed. The request was to treat microwave steam cooked seafood as a conventionally cooked raw animal product rather than a microwave cooked product, for which the safe cooking recommendation is more extensive owing to the complex temperature distributions in microwave heating. The request was motivated by a literature study that revealed a more uniform temperature distribution in microwave steam cooked whole lobster. In that study, single-point temperatures were recorded in various sections of the whole lobster, but only one temperature was recorded in the tail, although the large size of the tail could translate to multiple hot and cold points. The present study was conducted to examine lobster tail specifically, measuring temperatures at multiple points during microwave steam cooking. Large temperature differences, greater than 60°C at times, were found throughout the heating period. To compensate for such differences, the Food Code recommends a more extensive level of cooking when microwave energy, rather than conventional heat sources, is used. Therefore, a change in the Food Code regarding microwave steam heating cannot be recommended.

Data integration of structured and unstructured sources for assigning clinical codes to patient stays

PubMed Central

Luyckx, Kim; Luyten, Léon; Daelemans, Walter; Van den Bulcke, Tim

2016-01-01

Objective Enormous amounts of healthcare data are becoming increasingly accessible through the large-scale adoption of electronic health records. In this work, structured and unstructured (textual) data are combined to assign clinical diagnostic and procedural codes (specifically ICD-9-CM) to patient stays. We investigate whether integrating these heterogeneous data types improves prediction strength compared to using the data types in isolation. Methods Two separate data integration approaches were evaluated. Early data integration combines features of several sources within a single model, and late data integration learns a separate model per data source and combines these predictions with a meta-learner. This is evaluated on data sources and clinical codes from a broad set of medical specialties. Results When compared with the best individual prediction source, late data integration leads to improvements in predictive power (eg, overall F-measure increased from 30.6% to 38.3% for International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) diagnostic codes), while early data integration is less consistent. The predictive strength strongly differs between medical specialties, both for ICD-9-CM diagnostic and procedural codes. Discussion Structured data provides complementary information to unstructured data (and vice versa) for predicting ICD-9-CM codes. This can be captured most effectively by the proposed late data integration approach. Conclusions We demonstrated that models using multiple electronic health record data sources systematically outperform models using data sources in isolation in the task of predicting ICD-9-CM codes over a broad range of medical specialties. PMID:26316458

Flow of GE90 Turbofan Engine Simulated

NASA Technical Reports Server (NTRS)

Veres, Joseph P.

1999-01-01

The objective of this task was to create and validate a three-dimensional model of the GE90 turbofan engine (General Electric) using the APNASA (average passage) flow code. This was a joint effort between GE Aircraft Engines and the NASA Lewis Research Center. The goal was to perform an aerodynamic analysis of the engine primary flow path, in under 24 hours of CPU time, on a parallel distributed workstation system. Enhancements were made to the APNASA Navier-Stokes code to make it faster and more robust and to allow for the analysis of more arbitrary geometry. The resulting simulation exploited the use of parallel computations by using two levels of parallelism, with extremely high efficiency.The primary flow path of the GE90 turbofan consists of a nacelle and inlet, 49 blade rows of turbomachinery, and an exhaust nozzle. Secondary flows entering and exiting the primary flow path-such as bleed, purge, and cooling flows-were modeled macroscopically as source terms to accurately simulate the engine. The information on these source terms came from detailed descriptions of the cooling flow and from thermodynamic cycle system simulations. These provided boundary condition data to the three-dimensional analysis. A simplified combustor was used to feed boundary conditions to the turbomachinery. Flow simulations of the fan, high-pressure compressor, and high- and low-pressure turbines were completed with the APNASA code.

PRELIMINARY COUPLING OF THE MONTE CARLO CODE OPENMC AND THE MULTIPHYSICS OBJECT-ORIENTED SIMULATION ENVIRONMENT (MOOSE) FOR ANALYZING DOPPLER FEEDBACK IN MONTE CARLO SIMULATIONS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Matthew Ellis; Derek Gaston; Benoit Forget

In recent years the use of Monte Carlo methods for modeling reactors has become feasible due to the increasing availability of massively parallel computer systems. One of the primary challenges yet to be fully resolved, however, is the efficient and accurate inclusion of multiphysics feedback in Monte Carlo simulations. The research in this paper presents a preliminary coupling of the open source Monte Carlo code OpenMC with the open source Multiphysics Object-Oriented Simulation Environment (MOOSE). The coupling of OpenMC and MOOSE will be used to investigate efficient and accurate numerical methods needed to include multiphysics feedback in Monte Carlo codes.more » An investigation into the sensitivity of Doppler feedback to fuel temperature approximations using a two dimensional 17x17 PWR fuel assembly is presented in this paper. The results show a functioning multiphysics coupling between OpenMC and MOOSE. The coupling utilizes Functional Expansion Tallies to accurately and efficiently transfer pin power distributions tallied in OpenMC to unstructured finite element meshes used in MOOSE. The two dimensional PWR fuel assembly case also demonstrates that for a simplified model the pin-by-pin doppler feedback can be adequately replicated by scaling a representative pin based on pin relative powers.« less

Applications of Coding in Network Communications

ERIC Educational Resources Information Center

Chang, Christopher SungWook

2012-01-01

This thesis uses the tool of network coding to investigate fast peer-to-peer file distribution, anonymous communication, robust network construction under uncertainty, and prioritized transmission. In a peer-to-peer file distribution system, we use a linear optimization approach to show that the network coding framework significantly simplifies…

Kranc: a Mathematica package to generate numerical codes for tensorial evolution equations

NASA Astrophysics Data System (ADS)

Husa, Sascha; Hinder, Ian; Lechner, Christiane

2006-06-01

We present a suite of Mathematica-based computer-algebra packages, termed "Kranc", which comprise a toolbox to convert certain (tensorial) systems of partial differential evolution equations to parallelized C or Fortran code for solving initial boundary value problems. Kranc can be used as a "rapid prototyping" system for physicists or mathematicians handling very complicated systems of partial differential equations, but through integration into the Cactus computational toolkit we can also produce efficient parallelized production codes. Our work is motivated by the field of numerical relativity, where Kranc is used as a research tool by the authors. In this paper we describe the design and implementation of both the Mathematica packages and the resulting code, we discuss some example applications, and provide results on the performance of an example numerical code for the Einstein equations. Program summaryTitle of program: Kranc Catalogue identifier: ADXS_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADXS_v1_0 Program obtainable from: CPC Program Library, Queen's University of Belfast, N. Ireland Distribution format: tar.gz Computer for which the program is designed and others on which it has been tested: General computers which run Mathematica (for code generation) and Cactus (for numerical simulations), tested under Linux Programming language used: Mathematica, C, Fortran 90 Memory required to execute with typical data: This depends on the number of variables and gridsize, the included ADM example requires 4308 KB Has the code been vectorized or parallelized: The code is parallelized based on the Cactus framework. Number of bytes in distributed program, including test data, etc.: 1 578 142 Number of lines in distributed program, including test data, etc.: 11 711 Nature of physical problem: Solution of partial differential equations in three space dimensions, which are formulated as an initial value problem. In particular, the program is geared towards handling very complex tensorial equations as they appear, e.g., in numerical relativity. The worked out examples comprise the Klein-Gordon equations, the Maxwell equations, and the ADM formulation of the Einstein equations. Method of solution: The method of numerical solution is finite differencing and method of lines time integration, the numerical code is generated through a high level Mathematica interface. Restrictions on the complexity of the program: Typical numerical relativity applications will contain up to several dozen evolution variables and thousands of source terms, Cactus applications have shown scaling up to several thousand processors and grid sizes exceeding 500 3. Typical running time: This depends on the number of variables and the grid size: the included ADM example takes approximately 100 seconds on a 1600 MHz Intel Pentium M processor. Unusual features of the program: based on Mathematica and Cactus

Code for Calculating Regional Seismic Travel Time

DOE Office of Scientific and Technical Information (OSTI.GOV)

BALLARD, SANFORD; HIPP, JAMES; & BARKER, GLENN

The RSTT software computes predictions of the travel time of seismic energy traveling from a source to a receiver through 2.5D models of the seismic velocity distribution within the Earth. The two primary applications for the RSTT library are tomographic inversion studies and seismic event location calculations. In tomographic inversions studies, a seismologist begins with number of source-receiver travel time observations and an initial starting model of the velocity distribution within the Earth. A forward travel time calculator, such as the RSTT library, is used to compute predictions of each observed travel time and all of the residuals (observed minusmore » predicted travel time) are calculated. The Earth model is then modified in some systematic way with the goal of minimizing the residuals. The Earth model obtained in this way is assumed to be a better model than the starting model if it has lower residuals. The other major application for the RSTT library is seismic event location. Given an Earth model, an initial estimate of the location of a seismic event, and some number of observations of seismic travel time thought to have originated from that event, location codes systematically modify the estimate of the location of the event with the goal of minimizing the difference between the observed and predicted travel times. The second application, seismic event location, is routinely implemented by the military as part of its effort to monitor the Earth for nuclear tests conducted by foreign countries.« less

Entropy-Based Bounds On Redundancies Of Huffman Codes

NASA Technical Reports Server (NTRS)

Smyth, Padhraic J.

1992-01-01

Report presents extension of theory of redundancy of binary prefix code of Huffman type which includes derivation of variety of bounds expressed in terms of entropy of source and size of alphabet. Recent developments yielded bounds on redundancy of Huffman code in terms of probabilities of various components in source alphabet. In practice, redundancies of optimal prefix codes often closer to 0 than to 1.

40 CFR Appendix A to Subpart A of... - Tables

Code of Federal Regulations, 2010 CFR

2010-07-01

... phone number ✓ ✓ (6) FIPS code ✓ ✓ (7) Facility ID codes ✓ ✓ (8) Unit ID code ✓ ✓ (9) Process ID code... for Reporting on Emissions From Nonpoint Sources and Nonroad Mobile Sources, Where Required by 40 CFR... start date ✓ ✓ (3) Inventory end date ✓ ✓ (4) Contact name ✓ ✓ (5) Contact phone number ✓ ✓ (6) FIPS...

Dark Energy Survey Year 1 Results: redshift distributions of the weak-lensing source galaxies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoyle, B.; Gruen, D.; Bernstein, G. M.

We describe the derivation and validation of redshift distribution estimates and their uncertainties for the galaxies used as weak lensing sources in the Dark Energy Survey (DES) Year 1 cosmological analyses. The Bayesian Photometric Redshift (BPZ) code is used to assign galaxies to four redshift bins between z=0.2 and 1.3, and to produce initial estimates of the lensing-weighted redshift distributionsmore » $$n^i_{PZ}(z)$$ for bin i. Accurate determination of cosmological parameters depends critically on knowledge of $n^i$ but is insensitive to bin assignments or redshift errors for individual galaxies. The cosmological analyses allow for shifts $$n^i(z)=n^i_{PZ}(z-\\Delta z^i)$$ to correct the mean redshift of $n^i(z)$ for biases in $$n^i_{\\rm PZ}$$. The $$\\Delta z^i$$ are constrained by comparison of independently estimated 30-band photometric redshifts of galaxies in the COSMOS field to BPZ estimates made from the DES griz fluxes, for a sample matched in fluxes, pre-seeing size, and lensing weight to the DES weak-lensing sources. In companion papers, the $$\\Delta z^i$$ are further constrained by the angular clustering of the source galaxies around red galaxies with secure photometric redshifts at 0.15« less

Dark Energy Survey Year 1 Results: redshift distributions of the weak-lensing source galaxies

DOE PAGES

Hoyle, B.; Gruen, D.; Bernstein, G. M.; ...

2018-04-18

We describe the derivation and validation of redshift distribution estimates and their uncertainties for the galaxies used as weak lensing sources in the Dark Energy Survey (DES) Year 1 cosmological analyses. The Bayesian Photometric Redshift (BPZ) code is used to assign galaxies to four redshift bins between z=0.2 and 1.3, and to produce initial estimates of the lensing-weighted redshift distributionsmore » $$n^i_{PZ}(z)$$ for bin i. Accurate determination of cosmological parameters depends critically on knowledge of $n^i$ but is insensitive to bin assignments or redshift errors for individual galaxies. The cosmological analyses allow for shifts $$n^i(z)=n^i_{PZ}(z-\\Delta z^i)$$ to correct the mean redshift of $n^i(z)$ for biases in $$n^i_{\\rm PZ}$$. The $$\\Delta z^i$$ are constrained by comparison of independently estimated 30-band photometric redshifts of galaxies in the COSMOS field to BPZ estimates made from the DES griz fluxes, for a sample matched in fluxes, pre-seeing size, and lensing weight to the DES weak-lensing sources. In companion papers, the $$\\Delta z^i$$ are further constrained by the angular clustering of the source galaxies around red galaxies with secure photometric redshifts at 0.15« less

Dark Energy Survey Year 1 Results: Redshift distributions of the weak lensing source galaxies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoyle, B.; et al.

2017-08-04

We describe the derivation and validation of redshift distribution estimates and their uncertainties for the galaxies used as weak lensing sources in the Dark Energy Survey (DES) Year 1 cosmological analyses. The Bayesian Photometric Redshift (BPZ) code is used to assign galaxies to four redshift bins between z=0.2 and 1.3, and to produce initial estimates of the lensing-weighted redshift distributionsmore » $$n^i_{PZ}(z)$$ for bin i. Accurate determination of cosmological parameters depends critically on knowledge of $n^i$ but is insensitive to bin assignments or redshift errors for individual galaxies. The cosmological analyses allow for shifts $$n^i(z)=n^i_{PZ}(z-\\Delta z^i)$$ to correct the mean redshift of $n^i(z)$ for biases in $$n^i_{\\rm PZ}$$. The $$\\Delta z^i$$ are constrained by comparison of independently estimated 30-band photometric redshifts of galaxies in the COSMOS field to BPZ estimates made from the DES griz fluxes, for a sample matched in fluxes, pre-seeing size, and lensing weight to the DES weak-lensing sources. In companion papers, the $$\\Delta z^i$$ are further constrained by the angular clustering of the source galaxies around red galaxies with secure photometric redshifts at 0.15« less

48 CFR 252.227-7013 - Rights in technical data-Noncommercial items.

Code of Federal Regulations, 2011 CFR

2011-10-01

... causing a computer to perform a specific operation or series of operations. (3) Computer software means computer programs, source code, source code listings, object code listings, design details, algorithms... or will be developed exclusively with Government funds; (ii) Studies, analyses, test data, or similar...

48 CFR 252.227-7013 - Rights in technical data-Noncommercial items.

Code of Federal Regulations, 2012 CFR

2012-10-01

... causing a computer to perform a specific operation or series of operations. (3) Computer software means computer programs, source code, source code listings, object code listings, design details, algorithms... or will be developed exclusively with Government funds; (ii) Studies, analyses, test data, or similar...

48 CFR 252.227-7013 - Rights in technical data-Noncommercial items.

Code of Federal Regulations, 2014 CFR

2014-10-01

... causing a computer to perform a specific operation or series of operations. (3) Computer software means computer programs, source code, source code listings, object code listings, design details, algorithms... or will be developed exclusively with Government funds; (ii) Studies, analyses, test data, or similar...

48 CFR 252.227-7013 - Rights in technical data-Noncommercial items.

Code of Federal Regulations, 2010 CFR

2010-10-01

... causing a computer to perform a specific operation or series of operations. (3) Computer software means computer programs, source code, source code listings, object code listings, design details, algorithms... developed exclusively with Government funds; (ii) Studies, analyses, test data, or similar data produced for...

Measurement of track structure parameters of low and medium energy helium and carbon ions in nanometric volumes

NASA Astrophysics Data System (ADS)

Hilgers, G.; Bug, M. U.; Rabus, H.

2017-10-01

Ionization cluster size distributions produced in the sensitive volume of an ion-counting wall-less nanodosimeter by monoenergetic carbon ions with energies between 45 MeV and 150 MeV were measured at the TANDEM-ALPI ion accelerator facility complex of the LNL-INFN in Legnaro. Those produced by monoenergetic helium ions with energies between 2 MeV and 20 MeV were measured at the accelerator facilities of PTB and with a 241Am alpha particle source. C3H8 was used as the target gas. The ionization cluster size distributions were measured in narrow beam geometry with the primary beam passing the target volume at specified distances from its centre, and in broad beam geometry with a fan-like primary beam. By applying a suitable drift time window, the effective size of the target volume was adjusted to match the size of a DNA segment. The measured data were compared with the results of simulations obtained with the PTB Monte Carlo code PTra. Before the comparison, the simulated cluster size distributions were corrected with respect to the background of additional ionizations produced in the transport system of the ionized target gas molecules. Measured and simulated characteristics of the particle track structure are in good agreement for both types of primary particles and for both types of the irradiation geometry. As the range in tissue of the ions investigated is within the typical extension of a spread-out Bragg peak, these data are useful for benchmarking not only ‘general purpose’ track structure simulation codes, but also treatment planning codes used in hadron therapy. Additionally, these data sets may serve as a data base for codes modelling the induction of radiation damages at the DNA-level as they almost completely characterize the ionization component of the nanometric track structure.

A theoretical and experimental investigation of nonlinear propagation of ultrasound through tissue mimicking media

NASA Astrophysics Data System (ADS)

Rielly, Matthew Robert

An existing numerical model (known as the Bergen code) is used to investigate finite amplitude ultrasound propagation through multiple layers of tissue-like media. This model uses a finite difference method to solve the nonlinear parabolic KZK wave equation. The code is modified to include an arbitrary frequency dependence of absorption and transmission effects for wave propagation across a plane interface at normal incidence. In addition the code is adapted to calculate the total intensity loss associated with the absorption of the fundamental and nonlinearly generated harmonics. Measurements are also taken of the axial nonlinear pressure field generated from a circular focused, 2.25 MHz source, through single and multiple layered tissue mimicking fluids, for source pressures in the range from 13 kPa to 310 kPa. Two tissue mimicking fluids are developed to provide acoustic properties similar to amniotic fluid and a typical soft tissue. The values of the nonlinearity parameter, sound velocity and frequency dependence of attenuation for both fluids are presented, and the measurement procedures employed to obtain these characteristics are described in detail. These acoustic parameters, together with the measured source conditions are used as input to the numerical model, allowing the experimental conditions to be simulated. Extensive comparisons are made between the model's predictions and the axial pressure field measurements. Results are presented in the frequency domain showing the fundamental and three subsequent harmonic amplitudes on axis, as a function of axial distance. These show that significant nonlinear distortion can occur through media with characteristics typical of tissue. Time domain waveform comparisons are also made. An excellent agreement is found between theory and experiment indicating that the model can be used to predict nonlinear ultrasound propagation through multiple layers of tissue-like media. The numerical code is also used to model the intensity loss through layered tissue mimics and results are presented illustrating the effects of altering the layered medium on the magnitude and spatial distribution of intensity loss.

Modelling of the anti-neutrino production and spectra from a Magnox reactor

NASA Astrophysics Data System (ADS)

Mills, Robert W.; Mountford, David J.; Coleman, Jonathon P.; Metelko, Carl; Murdoch, Matthew; Schnellbach, Yan-Jie

2018-01-01

The anti-neutrino source properties of a fission reactor are governed by the production and beta decay of the radionuclides present and the summation of their individual anti-neutrino spectra. The fission product radionuclide production changes during reactor operation and different fissioning species give rise to different product distributions. It is thus possible to determine some details of reactor operation, such as power, from the anti-neutrino emission to confirm safeguards records. Also according to some published calculations, it may be feasible to observe different anti-neutrino spectra depending on the fissile contents of the reactor fuel and thus determine the reactor's fissile material inventory during operation which could considerable improve safeguards. In mid-2014 the University of Liverpool deployed a prototype anti-neutrino detector at the Wylfa R1 station in Anglesey, United Kingdom based upon plastic scintillator technology developed for the T2K project. The deployment was used to develop the detector electronics and software until the reactor was finally shutdown in December 2015. To support the development of this detector technology for reactor monitoring and to understand its capabilities, the National Nuclear Laboratory modelled this graphite moderated and natural uranium fuelled reactor with existing codes used to support Magnox reactor operations and waste management. The 3D multi-physics code PANTHER was used to determine the individual powers of each fuel element (8×6152) during the year and a half period of monitoring based upon reactor records. The WIMS/TRAIL/FISPIN code route was then used to determine the radionuclide inventory of each nuclide on a daily basis in each element. These nuclide inventories were then used with the BTSPEC code to determine the anti-neutrino spectra and source strength using JEFF-3.1.1 data. Finally the anti-neutrino source from the reactor for each day during the year and a half of monitored reactor operation was calculated. The results of the preliminary calculations are shown and limitations in the methods and data discussed.

a Framework for Distributed Mixed Language Scientific Applications

NASA Astrophysics Data System (ADS)

Quarrie, D. R.

The Object Management Group has defined an architecture (CORBA) for distributed object applications based on an Object Request Broker and Interface Definition Language. This project builds upon this architecture to establish a framework for the creation of mixed language scientific applications. A prototype compiler has been written that generates FORTRAN 90 or Eiffel stubs and skeletons and the required C++ glue code from an input IDL file that specifies object interfaces. This generated code can be used directly for non-distributed mixed language applications or in conjunction with the C++ code generated from a commercial IDL compiler for distributed applications. A feasibility study is presently underway to see whether a fully integrated software development environment for distributed, mixed-language applications can be created by modifying the back-end code generator of a commercial CASE tool to emit IDL.

Special issue on network coding

NASA Astrophysics Data System (ADS)

Monteiro, Francisco A.; Burr, Alister; Chatzigeorgiou, Ioannis; Hollanti, Camilla; Krikidis, Ioannis; Seferoglu, Hulya; Skachek, Vitaly

2017-12-01

Future networks are expected to depart from traditional routing schemes in order to embrace network coding (NC)-based schemes. These have created a lot of interest both in academia and industry in recent years. Under the NC paradigm, symbols are transported through the network by combining several information streams originating from the same or different sources. This special issue contains thirteen papers, some dealing with design aspects of NC and related concepts (e.g., fountain codes) and some showcasing the application of NC to new services and technologies, such as data multi-view streaming of video or underwater sensor networks. One can find papers that show how NC turns data transmission more robust to packet losses, faster to decode, and more resilient to network changes, such as dynamic topologies and different user options, and how NC can improve the overall throughput. This issue also includes papers showing that NC principles can be used at different layers of the networks (including the physical layer) and how the same fundamental principles can lead to new distributed storage systems. Some of the papers in this issue have a theoretical nature, including code design, while others describe hardware testbeds and prototypes.

On the biological plausibility of grandmother cells: implications for neural network theories in psychology and neuroscience.

PubMed

Bowers, Jeffrey S

2009-01-01

A fundamental claim associated with parallel distributed processing (PDP) theories of cognition is that knowledge is coded in a distributed manner in mind and brain. This approach rejects the claim that knowledge is coded in a localist fashion, with words, objects, and simple concepts (e.g. "dog"), that is, coded with their own dedicated representations. One of the putative advantages of this approach is that the theories are biologically plausible. Indeed, advocates of the PDP approach often highlight the close parallels between distributed representations learned in connectionist models and neural coding in brain and often dismiss localist (grandmother cell) theories as biologically implausible. The author reviews a range a data that strongly challenge this claim and shows that localist models provide a better account of single-cell recording studies. The author also contrast local and alternative distributed coding schemes (sparse and coarse coding) and argues that common rejection of grandmother cell theories in neuroscience is due to a misunderstanding about how localist models behave. The author concludes that the localist representations embedded in theories of perception and cognition are consistent with neuroscience; biology only calls into question the distributed representations often learned in PDP models.

Monte Carlo calculations of the cellular S-values for α-particle-emitting radionuclides incorporated into the nuclei of cancer cells of the MDA-MB231, MCF7 and PC3 lines.

PubMed

Rojas-Calderón, E L; Ávila, O; Ferro-Flores, G

2018-05-01

S-values (dose per unit of cumulated activity) for alpha particle-emitting radionuclides and monoenergetic alpha sources placed in the nuclei of three cancer cell models (MCF7, MDA-MB231 breast cancer cells and PC3 prostate cancer cells) were obtained by Monte Carlo simulation. The MCNPX code was used to calculate the fraction of energy deposited in the subcellular compartments due to the alpha sources in order to obtain the S-values. A comparison with internationally accepted S-values reported by the MIRD Cellular Committee for alpha sources in three sizes of spherical cells was also performed leading to an agreement within 4% when an alpha extended source uniformly distributed in the nucleus is simulated. This result allowed to apply the Monte Carlo Methodology to evaluate S-values for alpha particles in cancer cells. The calculation of S-values for nucleus, cytoplasm and membrane of cancer cells considering their particular geometry, distribution of the radionuclide source and chemical composition by means of Monte Carlo simulation provides a good approach for dosimetry assessment of alpha emitters inside cancer cells. Results from this work provide information and tools that may help researchers in the selection of appropriate radiopharmaceuticals in alpha-targeted cancer therapy and improve its dosimetry evaluation. Copyright © 2018 Elsevier Ltd. All rights reserved.

Spatially Resolved Observations of the Galactic Center Source IRS 21

NASA Astrophysics Data System (ADS)

Tanner, A.; Ghez, A. M.; Morris, M.; Becklin, E. E.; Cotera, A.; Ressler, M.; Werner, M.; Wizinowich, P.

2002-08-01

We present diffraction-limited 2-25 μm images obtained with the W. M. Keck 10 m telescopes that spatially resolve the cool source IRS 21, one of a small group of enigmatic objects in the central parsec of our Galaxy that have eluded classification. Modeled as a Gaussian, the azimuthally averaged intensity profile of IRS 21 has a half-width at half-maximum (HWHM) size of 650+/-80 AU at 2.2 μm and an average HWHM size of 1600+/-200 AU at mid-infrared wavelengths. These large apparent sizes imply an extended distribution of dust. The mid-infrared color map indicates that IRS 21 is a self-luminous source rather than an externally heated dust clump as originally suggested. The spectral energy distribution has distinct near- and mid-infrared components. A simple radiative transfer code, which simultaneously fits the near- and mid-infrared photometry and intensity profiles, supports a model in which the near-infrared radiation is scattered and extincted light from an embedded central source, while the mid-infrared emission is from thermally reradiating silicate dust. We argue that IRS 21 (and by analogy, the other luminous sources along the Northern Arm) is a massive star experiencing rapid mass loss and plowing through the Northern Arm, thereby generating a bow shock, which is spatially resolved in our observations.

LDPC-based iterative joint source-channel decoding for JPEG2000.

PubMed

Pu, Lingling; Wu, Zhenyu; Bilgin, Ali; Marcellin, Michael W; Vasic, Bane

2007-02-01

A framework is proposed for iterative joint source-channel decoding of JPEG2000 codestreams. At the encoder, JPEG2000 is used to perform source coding with certain error-resilience (ER) modes, and LDPC codes are used to perform channel coding. During decoding, the source decoder uses the ER modes to identify corrupt sections of the codestream and provides this information to the channel decoder. Decoding is carried out jointly in an iterative fashion. Experimental results indicate that the proposed method requires fewer iterations and improves overall system performance.

Development of probabilistic multimedia multipathway computer codes.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yu, C.; LePoire, D.; Gnanapragasam, E.

2002-01-01

The deterministic multimedia dose/risk assessment codes RESRAD and RESRAD-BUILD have been widely used for many years for evaluation of sites contaminated with residual radioactive materials. The RESRAD code applies to the cleanup of sites (soils) and the RESRAD-BUILD code applies to the cleanup of buildings and structures. This work describes the procedure used to enhance the deterministic RESRAD and RESRAD-BUILD codes for probabilistic dose analysis. A six-step procedure was used in developing default parameter distributions and the probabilistic analysis modules. These six steps include (1) listing and categorizing parameters; (2) ranking parameters; (3) developing parameter distributions; (4) testing parameter distributionsmore » for probabilistic analysis; (5) developing probabilistic software modules; and (6) testing probabilistic modules and integrated codes. The procedures used can be applied to the development of other multimedia probabilistic codes. The probabilistic versions of RESRAD and RESRAD-BUILD codes provide tools for studying the uncertainty in dose assessment caused by uncertain input parameters. The parameter distribution data collected in this work can also be applied to other multimedia assessment tasks and multimedia computer codes.« less

Power Aware Signal Processing Environment (PASPE) for PAC/C

DTIC Science & Technology

2003-02-01

vs. FFT Size For our implementation , the Annapolis FFT core was radix-256, and therefore the smallest PN code length that could be processed was the...PN-64. A C- code version of correlate was compared to the FPGA 61 implementation . The results in Figure 68 show that for a PN-1024, the...12a. DISTRIBUTION / AVAILABILITY STATEMENT APPROVED FOR PUBLIC RELEASE; DISTRIBUTION UNLIMITED. 12b. DISTRIBUTION CODE 13. ABSTRACT (Maximum

Azimuthal Dependence of the Ground Motion Variability from Scenario Modeling of the 2014 Mw6.0 South Napa, California, Earthquake Using an Advanced Kinematic Source Model

NASA Astrophysics Data System (ADS)

Gallovič, F.

2017-09-01

Strong ground motion simulations require physically plausible earthquake source model. Here, I present the application of such a kinematic model introduced originally by Ruiz et al. (Geophys J Int 186:226-244, 2011). The model is constructed to inherently provide synthetics with the desired omega-squared spectral decay in the full frequency range. The source is composed of randomly distributed overlapping subsources with fractal number-size distribution. The position of the subsources can be constrained by prior knowledge of major asperities (stemming, e.g., from slip inversions), or can be completely random. From earthquake physics point of view, the model includes positive correlation between slip and rise time as found in dynamic source simulations. Rupture velocity and rise time follows local S-wave velocity profile, so that the rupture slows down and rise times increase close to the surface, avoiding unrealistically strong ground motions. Rupture velocity can also have random variations, which result in irregular rupture front while satisfying the causality principle. This advanced kinematic broadband source model is freely available and can be easily incorporated into any numerical wave propagation code, as the source is described by spatially distributed slip rate functions, not requiring any stochastic Green's functions. The source model has been previously validated against the observed data due to the very shallow unilateral 2014 Mw6 South Napa, California, earthquake; the model reproduces well the observed data including the near-fault directivity (Seism Res Lett 87:2-14, 2016). The performance of the source model is shown here on the scenario simulations for the same event. In particular, synthetics are compared with existing ground motion prediction equations (GMPEs), emphasizing the azimuthal dependence of the between-event ground motion variability. I propose a simple model reproducing the azimuthal variations of the between-event ground motion variability, providing an insight into possible refinement of GMPEs' functional forms.

48 CFR 252.227-7013 - Rights in technical data-Noncommercial items.

Code of Federal Regulations, 2013 CFR

2013-10-01

... causing a computer to perform a specific operation or series of operations. (3) Computer software means computer programs, source code, source code listings, object code listings, design details, algorithms... funds; (ii) Studies, analyses, test data, or similar data produced for this contract, when the study...

Dark Energy Survey Year 1 Results: Cross-Correlation Redshifts - Methods and Systematics Characterization

DOE PAGES

Gatti, M.

2018-02-22

We use numerical simulations to characterize the performance of a clustering-based method to calibrate photometric redshift biases. In particular, we cross-correlate the weak lensing (WL) source galaxies from the Dark Energy Survey Year 1 (DES Y1) sample with redMaGiC galaxies (luminous red galaxies with secure photometric red- shifts) to estimate the redshift distribution of the former sample. The recovered redshift distributions are used to calibrate the photometric redshift bias of standard photo-z methods applied to the same source galaxy sample. We also apply the method to three photo-z codes run in our simulated data: Bayesian Photometric Redshift (BPZ), Directional Neighborhoodmore » Fitting (DNF), and Random Forest-based photo-z (RF). We characterize the systematic uncertainties of our calibration procedure, and find that these systematic uncertainties dominate our error budget. The dominant systematics are due to our assumption of unevolving bias and clustering across each redshift bin, and to differences between the shapes of the redshift distributions derived by clustering vs photo-z's. The systematic uncertainty in the mean redshift bias of the source galaxy sample is z ≲ 0.02, though the precise value depends on the redshift bin under consideration. Here, we discuss possible ways to mitigate the impact of our dominant systematics in future analyses.« less

Dark Energy Survey Year 1 Results: Cross-Correlation Redshifts - Methods and Systematics Characterization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gatti, M.

We use numerical simulations to characterize the performance of a clustering-based method to calibrate photometric redshift biases. In particular, we cross-correlate the weak lensing (WL) source galaxies from the Dark Energy Survey Year 1 (DES Y1) sample with redMaGiC galaxies (luminous red galaxies with secure photometric red- shifts) to estimate the redshift distribution of the former sample. The recovered redshift distributions are used to calibrate the photometric redshift bias of standard photo-z methods applied to the same source galaxy sample. We also apply the method to three photo-z codes run in our simulated data: Bayesian Photometric Redshift (BPZ), Directional Neighborhoodmore » Fitting (DNF), and Random Forest-based photo-z (RF). We characterize the systematic uncertainties of our calibration procedure, and find that these systematic uncertainties dominate our error budget. The dominant systematics are due to our assumption of unevolving bias and clustering across each redshift bin, and to differences between the shapes of the redshift distributions derived by clustering vs photo-z's. The systematic uncertainty in the mean redshift bias of the source galaxy sample is z ≲ 0.02, though the precise value depends on the redshift bin under consideration. Here, we discuss possible ways to mitigate the impact of our dominant systematics in future analyses.« less

Laser beam-profile impression and target thickness impact on laser-accelerated protons

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schollmeier, M.; Harres, K.; Nuernberg, F.

Experimental results on the influence of the laser focal spot shape onto the beam profile of laser-accelerated protons from gold foils are reported. The targets' microgrooved rear side, together with a stack of radiochromic films, allowed us to deduce the energy-dependent proton source-shape and size, respectively. The experiments show, that shape and size of the proton source depend only weakly on target thickness as well as shape of the laser focus, although they strongly influence the proton's intensity distribution. It was shown that the laser creates an electron beam that closely follows the laser beam topology, which is maintained duringmore » the propagation through the target. Protons are then accelerated from the rear side with an electron created electric field of a similar shape. Simulations with the Sheath-Accelerated Beam Ray-tracing for IoN Analysis code SABRINA, which calculates the proton distribution in the detector for a given laser-beam profile, show that the electron distribution during the transport through a thick target (50 {mu}m Au) is only modified due to multiple small angle scattering. Thin targets (10 {mu}m) show large source sizes of over 100 {mu}m diameter for 5 MeV protons, which cannot be explained by multiple scattering only and are most likely the result of refluxing electrons.« less

25 CFR 18.104 - May a tribe include provisions in its tribal probate code regarding the distribution and descent...

Code of Federal Regulations, 2010 CFR

2010-04-01

... 25 Indians 1 2010-04-01 2010-04-01 false May a tribe include provisions in its tribal probate code regarding the distribution and descent of trust personalty? 18.104 Section 18.104 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR PROBATE TRIBAL PROBATE CODES Approval of Tribal Probate Codes § 18.104 May a tribe include provisions in...

The Newick utilities: high-throughput phylogenetic tree processing in the Unix shell

PubMed Central

Junier, Thomas; Zdobnov, Evgeny M.

2010-01-01

Summary: We present a suite of Unix shell programs for processing any number of phylogenetic trees of any size. They perform frequently-used tree operations without requiring user interaction. They also allow tree drawing as scalable vector graphics (SVG), suitable for high-quality presentations and further editing, and as ASCII graphics for command-line inspection. As an example we include an implementation of bootscanning, a procedure for finding recombination breakpoints in viral genomes. Availability: C source code, Python bindings and executables for various platforms are available from http://cegg.unige.ch/newick_utils. The distribution includes a manual and example data. The package is distributed under the BSD License. Contact: thomas.junier@unige.ch PMID:20472542

Characterization of germanium detectors for the measurement of the angular distribution of prompt γ-rays at the ANNRI in the MLF of the J-PARC

NASA Astrophysics Data System (ADS)

Takada, S.; Okudaira, T.; Goto, F.; Hirota, K.; Kimura, A.; Kitaguchi, M.; Koga, J.; Nakao, T.; Sakai, K.; Shimizu, H. M.; Yamamoto, T.; Yoshioka, T.

2018-02-01

In this study, the germanium detector assembly, installed at the Accurate Neutron-Nuclear Reaction measurement Instruments (ANNRI) in the Material and Life Science Facility (MLF) operated by the Japan Proton Accelerator Research Complex (J-PARC), has been characterized for extension to the measurement of the angular distribution of individual γ-ray transitions from neutron-induced compound states. We have developed a Monte Carlo simulation code using the GEANT4 toolkit, which can reproduce the pulse-height spectra of γ-rays from radioactive sources and (n,γ) reactions. The simulation is applicable to the measurement of γ-rays in the energy region of 0.5-11.0 MeV.

MAGIC-f Gel in Nuclear Medicine Dosimetry: study in an external beam of Iodine-131

NASA Astrophysics Data System (ADS)

Schwarcke, M.; Marques, T.; Garrido, C.; Nicolucci, P.; Baffa, O.

2010-11-01

MAGIC-f gel applicability in Nuclear Medicine dosimetry was investigated by exposure to a 131I source. Calibration was made to provide known absorbed doses in different positions around the source. The absorbed dose in gel was compared with a Monte Carlo Simulation using PENELOPE code and a thermoluminescent dosimetry (TLD). Using MRI analysis for the gel a R2-dose sensitivity of 0.23 s-1Gy-1was obtained. The agreement between dose-distance curves obtained with Monte Carlo simulation and TLD was better than 97% and for MAGIC-f and TLD was better than 98%. The results show the potential of polymer gel for application in nuclear medicine where three dimensional dose distribution is demanded.

Calculations of the skyshine gamma-ray dose rates from independent spent fuel storage installations (ISFSI) under worst case accident conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pace, J.V. III; Cramer, S.N.; Knight, J.R.

1980-09-01

Calculations of the skyshine gamma-ray dose rates from three spent fuel storage pools under worst case accident conditions have been made using the discrete ordinates code DOT-IV and the Monte Carlo code MORSE and have been compared to those of two previous methods. The DNA 37N-21G group cross-section library was utilized in the calculations, together with the Claiborne-Trubey gamma-ray dose factors taken from the same library. Plots of all results are presented. It was found that the dose was a strong function of the iron thickness over the fuel assemblies, the initial angular distribution of the emitted radiation, and themore » photon source near the top of the assemblies. 16 refs., 11 figs., 7 tabs.« less

Spectral analysis of variable-length coded digital signals

NASA Astrophysics Data System (ADS)

Cariolaro, G. L.; Pierobon, G. L.; Pupolin, S. G.

1982-05-01

A spectral analysis is conducted for a variable-length word sequence by an encoder driven by a stationary memoryless source. A finite-state sequential machine is considered as a model of the line encoder, and the spectral analysis of the encoded message is performed under the assumption that the sourceword sequence is composed of independent identically distributed words. Closed form expressions for both the continuous and discrete parts of the spectral density are derived in terms of the encoder law and sourceword statistics. The jump part exhibits jumps at multiple integers of per lambda(sub 0)T, where lambda(sub 0) is the greatest common divisor of the possible codeword lengths, and T is the symbol period. The derivation of the continuous part can be conveniently factorized, and the theory is applied to the spectral analysis of BnZS and HDBn codes.

Calculated effects of backscattering on skin dosimetry for nuclear fuel fragments.

PubMed

Aydarous, A Sh

2008-01-01

The size of hot particles contained in nuclear fallout ranges from 10 nm to 20 microm for the worldwide weapons fallout. Hot particles from nuclear power reactors can be significantly bigger (100 microm to several millimetres). Electron backscattering from such particles is a prominent secondary effect in beta dosimetry for radiological protection purposes, such as skin dosimetry. In this study, the effect of electron backscattering due to hot particles contamination on skin dose is investigated. These include parameters such as detector area, source radius, source energy, scattering material and source density. The Monte-Carlo Neutron Particle code (MCNP4C) was used to calculate the depth dose distribution for 10 different beta sources and various materials. The backscattering dose factors (BSDF) were then calculated. A significant dependence is shown for the BSDF magnitude upon detector area, source radius and scatterers. It is clearly shown that the BSDF increases with increasing detector area. For high Z scatterers, the BSDF can reach as high as 40 and 100% for sources with radii 0.1 and 0.0001 cm, respectively. The variation of BSDF with source radius, source energy and source density is discussed.

HDR {sup 192}Ir source speed measurements using a high speed video camera

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fonseca, Gabriel P.; Viana, Rodrigo S. S.; Yoriyaz, Hélio

Purpose: The dose delivered with a HDR {sup 192}Ir afterloader can be separated into a dwell component, and a transit component resulting from the source movement. The transit component is directly dependent on the source speed profile and it is the goal of this study to measure accurate source speed profiles. Methods: A high speed video camera was used to record the movement of a {sup 192}Ir source (Nucletron, an Elekta company, Stockholm, Sweden) for interdwell distances of 0.25–5 cm with dwell times of 0.1, 1, and 2 s. Transit dose distributions were calculated using a Monte Carlo code simulatingmore » the source movement. Results: The source stops at each dwell position oscillating around the desired position for a duration up to (0.026 ± 0.005) s. The source speed profile shows variations between 0 and 81 cm/s with average speed of ∼33 cm/s for most of the interdwell distances. The source stops for up to (0.005 ± 0.001) s at nonprogrammed positions in between two programmed dwell positions. The dwell time correction applied by the manufacturer compensates the transit dose between the dwell positions leading to a maximum overdose of 41 mGy for the considered cases and assuming an air-kerma strength of 48 000 U. The transit dose component is not uniformly distributed leading to over and underdoses, which is within 1.4% for commonly prescribed doses (3–10 Gy). Conclusions: The source maintains its speed even for the short interdwell distances. Dose variations due to the transit dose component are much lower than the prescribed treatment doses for brachytherapy, although transit dose component should be evaluated individually for clinical cases.« less

Two-terminal video coding.

PubMed

Yang, Yang; Stanković, Vladimir; Xiong, Zixiang; Zhao, Wei

2009-03-01

Following recent works on the rate region of the quadratic Gaussian two-terminal source coding problem and limit-approaching code designs, this paper examines multiterminal source coding of two correlated, i.e., stereo, video sequences to save the sum rate over independent coding of both sequences. Two multiterminal video coding schemes are proposed. In the first scheme, the left sequence of the stereo pair is coded by H.264/AVC and used at the joint decoder to facilitate Wyner-Ziv coding of the right video sequence. The first I-frame of the right sequence is successively coded by H.264/AVC Intracoding and Wyner-Ziv coding. An efficient stereo matching algorithm based on loopy belief propagation is then adopted at the decoder to produce pixel-level disparity maps between the corresponding frames of the two decoded video sequences on the fly. Based on the disparity maps, side information for both motion vectors and motion-compensated residual frames of the right sequence are generated at the decoder before Wyner-Ziv encoding. In the second scheme, source splitting is employed on top of classic and Wyner-Ziv coding for compression of both I-frames to allow flexible rate allocation between the two sequences. Experiments with both schemes on stereo video sequences using H.264/AVC, LDPC codes for Slepian-Wolf coding of the motion vectors, and scalar quantization in conjunction with LDPC codes for Wyner-Ziv coding of the residual coefficients give a slightly lower sum rate than separate H.264/AVC coding of both sequences at the same video quality.

Impact of the vaginal applicator and dummy pellets on the dosimetry parameters of Cs-137 brachytherapy source.

PubMed

Sina, Sedigheh; Faghihi, Reza; Meigooni, Ali S; Mehdizadeh, Simin; Mosleh Shirazi, M Amin; Zehtabian, Mehdi

2011-05-19

In this study, dose rate distribution around a spherical 137Cs pellet source, from a low-dose-rate (LDR) Selectron remote afterloading system used in gynecological brachytherapy, has been determined using experimental and Monte Carlo simulation techniques. Monte Carlo simulations were performed using MCNP4C code, for a single pellet source in water medium and Plexiglas, and measurements were performed in Plexiglas phantom material using LiF TLD chips. Absolute dose rate distribution and the dosimetric parameters, such as dose rate constant, radial dose functions, and anisotropy functions, were obtained for a single pellet source. In order to investigate the effect of the applicator and surrounding pellets on dosimetric parameters of the source, the simulations were repeated for six different arrangements with a single active source and five non-active pellets inside central metallic tubing of a vaginal cylindrical applicator. In commercial treatment planning systems (TPS), the attenuation effects of the applicator and inactive spacers on total dose are neglected. The results indicate that this effect could lead to overestimation of the calculated F(r,θ), by up to 7% along the longitudinal axis of the applicator, especially beyond the applicator tip. According to the results obtained in this study, in a real situation in treatment of patients using cylindrical vaginal applicator and using several active pellets, there will be a large discrepancy between the result of superposition and Monte Carlo simulations.

Biosurveillance applying scan statistics with multiple, disparate data sources.

PubMed

Burkom, Howard S

2003-06-01

Researchers working on the Department of Defense Global Emerging Infections System (DoD-GEIS) pilot system, the Electronic Surveillance System for the Early Notification of Community-Based Epidemics (ESSENCE), have applied scan statistics for early outbreak detection using both traditional and nontraditional data sources. These sources include medical data indexed by International Classification of Disease, 9th Revision (ICD-9) diagnosis codes, as well as less-specific, but potentially timelier, indicators such as records of over-the-counter remedy sales and of school absenteeism. Early efforts employed the Kulldorff scan statistic as implemented in the SaTScan software of the National Cancer Institute. A key obstacle to this application is that the input data streams are typically based on time-varying factors, such as consumer behavior, rather than simply on the populations of the component subregions. We have used both modeling and recent historical data distributions to obtain background spatial distributions. Data analyses have provided guidance on how to condition and model input data to avoid excessive clustering. We have used this methodology in combining data sources for both retrospective studies of known outbreaks and surveillance of high-profile events of concern to local public health authorities. We have integrated the scan statistic capability into a Microsoft Access-based system in which we may include or exclude data sources, vary time windows separately for different data sources, censor data from subsets of individual providers or subregions, adjust the background computation method, and run retrospective or simulated studies.

Comparison of TG-43 dosimetric parameters of brachytherapy sources obtained by three different versions of MCNP codes.

PubMed

Zaker, Neda; Zehtabian, Mehdi; Sina, Sedigheh; Koontz, Craig; Meigooni, Ali S

2016-03-08

Monte Carlo simulations are widely used for calculation of the dosimetric parameters of brachytherapy sources. MCNP4C2, MCNP5, MCNPX, EGS4, EGSnrc, PTRAN, and GEANT4 are among the most commonly used codes in this field. Each of these codes utilizes a cross-sectional library for the purpose of simulating different elements and materials with complex chemical compositions. The accuracies of the final outcomes of these simulations are very sensitive to the accuracies of the cross-sectional libraries. Several investigators have shown that inaccuracies of some of the cross section files have led to errors in 125I and 103Pd parameters. The purpose of this study is to compare the dosimetric parameters of sample brachytherapy sources, calculated with three different versions of the MCNP code - MCNP4C, MCNP5, and MCNPX. In these simulations for each source type, the source and phantom geometries, as well as the number of the photons, were kept identical, thus eliminating the possible uncertainties. The results of these investigations indicate that for low-energy sources such as 125I and 103Pd there are discrepancies in gL(r) values. Discrepancies up to 21.7% and 28% are observed between MCNP4C and other codes at a distance of 6 cm for 103Pd and 10 cm for 125I from the source, respectively. However, for higher energy sources, the discrepancies in gL(r) values are less than 1.1% for 192Ir and less than 1.2% for 137Cs between the three codes.

VizieR Online Data Catalog: Panchromatic SED of Herschel sources (Berta+, 2013)

NASA Astrophysics Data System (ADS)

Berta, S.; Lutz, D.; Santini, P.; Wuyts, S.; Rosario, D.; Brisbin, D.; Cooray, A.; Franceschini, A.; Gruppioni, C.; Hatziminaoglou, E.; Hwang, H. S.; Le Floc'h, E.; Magnelli, B.; Nordon, R.; Oliver, S.; Page, M. J.; Popesso, P.; Pozzetti, L.; Pozzi, F.; Riguccini, L.; Rodighiero, G.; Roseboom, I.; Scott, D.; Symeonidis, M.; Valtchanov, I.; Viero, M.; Wang, L.

2016-06-01

Combining far-infrared Herschel photometry from the PACS Evolutionary Probe (PEP) and Herschel Multi-tiered Extragalactic Survey (HerMES) guaranteed time programs with ancillary datasets in the GOODS-N, GOODS-S and COSMOS fields, it is possible to sample the 8-500 micron spectral energy distributions of galaxies with at least 7-10 bands. Extending to the UV, optical, and near- infrared, the number of bands increases up to 43. We reproduce the distribution of galaxies in a carefully selected 10 restframe color space, based on this rich data-set, using a superposition of multi-variate Gaussian modes. We use this model to classify galaxies and build median spectral energy distributions (SEDs) of each class, which are then fitted with a modified version of the MAGPHYS code that combines stellar light, emission from dust heated by stars and a possible warm dust contribution heated by an Active Galactic Nucleus (AGN). The color distribution of galaxies in each of the considered fields can be well described with the combination of 6-9 classes, spanning a large range of far- to near-IR luminosity ratios, as well as different strength of the AGN contribution to bolometric luminosities. The defined Gaussian grouping is used to identify rare or odd sources. The zoology of outliers includes Herschel-detected ellipticals, very blue z~1 Lyα-break galaxies, quiescent spirals, and torus-dominated AGN with star formation. Out of these groups and outliers, a new template library is assembled, consisting of 32 SEDs describing the intrinsic scatter in the restframe UV-to-submm colors of infrared galaxies. This library is tested against L(IR) estimates with and without Herschel data included, and compared to eight other popular methods often adopted in the literature. When implementing Herschel photometry, these approaches produce L(IR) values consistent with each other within a median absolute deviation of 10-20%, the scatter being dominated more by fine tuning of the codes, rather than by the choice of SED templates. Finally, the library is used to classify 24 micron detected sources in PEP GOODS fields on the basis of AGN content, L(60)/L(100) color and L(160)/L(1.6) luminosity ratio. AGN appear to be distributed in M*-SFR along with all other galaxies, regardless of the amount of infrared luminosity they are powering, with the tendency to lie on the high SFR side of the "main sequence". The incidence of warmer star-forming sources grows for objects with higher specific star formation rates, and they tend to populate the "off-sequence" region of the M*-SFR-z space. (4 data files).

A high resolution liquid xenon imaging telescope for 0.3-10 MeV gamma-ray astrophysics: Construction and initial balloon flights

NASA Technical Reports Server (NTRS)

Aprile, Elena

1994-01-01

An instrument is described which will provide a direct image of gamma-ray line or continuum sources in the energy range 300 keV to 10 MeV. The use of this instrument to study the celestial distribution of the (exp 26)Al isotope by observing the 1.809 MeV deexcitation gamma-ray line is illustrated. The source location accuracy is 2' or better. The imaging telescope is a liquid xenon time projection chamber coupled with a coded aperture mask (LXe-CAT). This instrument will confirm and extend the COMPTEL observations from the Compton Gamma-Ray Observatory (CGRO) with an improved capability for identifying the actual Galactic source or sources of (exp 26)Al, which are currently not known with certainty. sources currently under consideration include red giants on the asymptotic giant branch (AGB), novae, Type 1b or Type 2 supernovae, Wolf-Rayet stars and cosmic-rays interacting in molecular clouds. The instrument could also identify a local source of the celestial 1.809 MeV gamma-ray line, such as a recent nearby supernova.

Coarse Grid Modeling of Turbine Film Cooling Flows Using Volumetric Source Terms

NASA Technical Reports Server (NTRS)

Heidmann, James D.; Hunter, Scott D.

2001-01-01

The recent trend in numerical modeling of turbine film cooling flows has been toward higher fidelity grids and more complex geometries. This trend has been enabled by the rapid increase in computing power available to researchers. However, the turbine design community requires fast turnaround time in its design computations, rendering these comprehensive simulations ineffective in the design cycle. The present study describes a methodology for implementing a volumetric source term distribution in a coarse grid calculation that can model the small-scale and three-dimensional effects present in turbine film cooling flows. This model could be implemented in turbine design codes or in multistage turbomachinery codes such as APNASA, where the computational grid size may be larger than the film hole size. Detailed computations of a single row of 35 deg round holes on a flat plate have been obtained for blowing ratios of 0.5, 0.8, and 1.0, and density ratios of 1.0 and 2.0 using a multiblock grid system to resolve the flows on both sides of the plate as well as inside the hole itself. These detailed flow fields were spatially averaged to generate a field of volumetric source terms for each conservative flow variable. Solutions were also obtained using three coarse grids having streamwise and spanwise grid spacings of 3d, 1d, and d/3. These coarse grid solutions used the integrated hole exit mass, momentum, energy, and turbulence quantities from the detailed solutions as volumetric source terms. It is shown that a uniform source term addition over a distance from the wall on the order of the hole diameter is able to predict adiabatic film effectiveness better than a near-wall source term model, while strictly enforcing correct values of integrated boundary layer quantities.

Using the Astrophysics Source Code Library

NASA Astrophysics Data System (ADS)

Allen, Alice; Teuben, P. J.; Berriman, G. B.; DuPrie, K.; Hanisch, R. J.; Mink, J. D.; Nemiroff, R. J.; Shamir, L.; Wallin, J. F.

2013-01-01

The Astrophysics Source Code Library (ASCL) is a free on-line registry of source codes that are of interest to astrophysicists; with over 500 codes, it is the largest collection of scientist-written astrophysics programs in existence. All ASCL source codes have been used to generate results published in or submitted to a refereed journal and are available either via a download site or from an identified source. An advisory committee formed in 2011 provides input and guides the development and expansion of the ASCL, and since January 2012, all accepted ASCL entries are indexed by ADS. Though software is increasingly important for the advancement of science in astrophysics, these methods are still often hidden from view or difficult to find. The ASCL (ascl.net/) seeks to improve the transparency and reproducibility of research by making these vital methods discoverable, and to provide recognition and incentive to those who write and release programs useful for astrophysics research. This poster provides a description of the ASCL, an update on recent additions, and the changes in the astrophysics community we are starting to see because of the ASCL.

McSKY: A hybrid Monte-Carlo lime-beam code for shielded gamma skyshine calculations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shultis, J.K.; Faw, R.E.; Stedry, M.H.

1994-07-01

McSKY evaluates skyshine dose from an isotropic, monoenergetic, point photon source collimated into either a vertical cone or a vertical structure with an N-sided polygon cross section. The code assumes an overhead shield of two materials, through the user can specify zero shield thickness for an unshielded calculation. The code uses a Monte-Carlo algorithm to evaluate transport through source shields and the integral line source to describe photon transport through the atmosphere. The source energy must be between 0.02 and 100 MeV. For heavily shielded sources with energies above 20 MeV, McSKY results must be used cautiously, especially at detectormore » locations near the source.« less

A virtual photon energy fluence model for Monte Carlo dose calculation.

PubMed

Fippel, Matthias; Haryanto, Freddy; Dohm, Oliver; Nüsslin, Fridtjof; Kriesen, Stephan

2003-03-01

The presented virtual energy fluence (VEF) model of the patient-independent part of the medical linear accelerator heads, consists of two Gaussian-shaped photon sources and one uniform electron source. The planar photon sources are located close to the bremsstrahlung target (primary source) and to the flattening filter (secondary source), respectively. The electron contamination source is located in the plane defining the lower end of the filter. The standard deviations or widths and the relative weights of each source are free parameters. Five other parameters correct for fluence variations, i.e., the horn or central depression effect. If these parameters and the field widths in the X and Y directions are given, the corresponding energy fluence distribution can be calculated analytically and compared to measured dose distributions in air. This provides a method of fitting the free parameters using the measurements for various square and rectangular fields and a fixed number of monitor units. The next step in generating the whole set of base data is to calculate monoenergetic central axis depth dose distributions in water which are used to derive the energy spectrum by deconvolving the measured depth dose curves. This spectrum is also corrected to take the off-axis softening into account. The VEF model is implemented together with geometry modules for the patient specific part of the treatment head (jaws, multileaf collimator) into the XVMC dose calculation engine. The implementation into other Monte Carlo codes is possible based on the information in this paper. Experiments are performed to verify the model by comparing measured and calculated dose distributions and output factors in water. It is demonstrated that open photon beams of linear accelerators from two different vendors are accurately simulated using the VEF model. The commissioning procedure of the VEF model is clinically feasible because it is based on standard measurements in air and water. It is also useful for IMRT applications because a full Monte Carlo simulation of the treatment head would be too time-consuming for many small fields.

Joint design of QC-LDPC codes for coded cooperation system with joint iterative decoding

NASA Astrophysics Data System (ADS)

Zhang, Shunwai; Yang, Fengfan; Tang, Lei; Ejaz, Saqib; Luo, Lin; Maharaj, B. T.

2016-03-01

In this paper, we investigate joint design of quasi-cyclic low-density-parity-check (QC-LDPC) codes for coded cooperation system with joint iterative decoding in the destination. First, QC-LDPC codes based on the base matrix and exponent matrix are introduced, and then we describe two types of girth-4 cycles in QC-LDPC codes employed by the source and relay. In the equivalent parity-check matrix corresponding to the jointly designed QC-LDPC codes employed by the source and relay, all girth-4 cycles including both type I and type II are cancelled. Theoretical analysis and numerical simulations show that the jointly designed QC-LDPC coded cooperation well combines cooperation gain and channel coding gain, and outperforms the coded non-cooperation under the same conditions. Furthermore, the bit error rate performance of the coded cooperation employing jointly designed QC-LDPC codes is better than those of random LDPC codes and separately designed QC-LDPC codes over AWGN channels.

Binary weight distributions of some Reed-Solomon codes

NASA Technical Reports Server (NTRS)

Pollara, F.; Arnold, S.

1992-01-01

The binary weight distributions of the (7,5) and (15,9) Reed-Solomon (RS) codes and their duals are computed using the MacWilliams identities. Several mappings of symbols to bits are considered and those offering the largest binary minimum distance are found. These results are then used to compute bounds on the soft-decoding performance of these codes in the presence of additive Gaussian noise. These bounds are useful for finding large binary block codes with good performance and for verifying the performance obtained by specific soft-coding algorithms presently under development.

Chromaticity calculations and code comparisons for x-ray lithography source XLS and SXLS rings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Parsa, Z.

1988-06-16

This note presents the chromaticity calculations and code comparison results for the (x-ray lithography source) XLS (Chasman Green, XUV Cosy lattice) and (2 magnet 4T) SXLS lattices, with the standard beam optic codes, including programs SYNCH88.5, MAD6, PATRICIA88.4, PATPET88.2, DIMAD, BETA, and MARYLIE. This analysis is a part of our ongoing accelerator physics code studies. 4 figs., 10 tabs.

The Astrophysics Source Code Library: Where Do We Go from Here?

NASA Astrophysics Data System (ADS)

Allen, A.; Berriman, B.; DuPrie, K.; Hanisch, R. J.; Mink, J.; Nemiroff, R. J.; Shamir, L.; Shortridge, K.; Taylor, M. B.; Teuben, P.; Wallen, J.

2014-05-01

The Astrophysics Source Code Library1, started in 1999, has in the past three years grown from a repository for 40 codes to a registry of over 700 codes that are now indexed by ADS. What comes next? We examine the future of the , the challenges facing it, the rationale behind its practices, and the need to balance what we might do with what we have the resources to accomplish.

Signal Transfer Function of the Knox-Thompson Speckle Imaging Technique

DTIC Science & Technology

1988-08-15

r - q/2) - ¢[r’ + (q - A )/2] 4. P. Nisenson, R. V. Stachnik, M. Karovska , and R. W. Noyes, " A + O’ - (q - A /2 1 2 1 new optical source associated...AD- A 197 716 opR 0 UMENTArON PAGE unclassified 4 - E MARKINGS i" 2a SECURITY CLASSIFICATION AUTHORI Y " I C #. DISTRIBUTION IAVAILABILITY OF REPORT...City, State, and ZIPCode) 7b ADDRESS (City, State, and ZIP Code) LHanscom AFB Ma.ssachusettai, 01731-5000 a . NAME OF FUNDING/SPONSORING 18b OFFICE

Research in computer science

NASA Technical Reports Server (NTRS)

Ortega, J. M.

1984-01-01

Several short summaries of the work performed during this reporting period are presented. Topics discussed in this document include: (1) resilient seeded errors via simple techniques; (2) knowledge representation for engineering design; (3) analysis of faults in a multiversion software experiment; (4) implementation of parallel programming environment; (5) symbolic execution of concurrent programs; (6) two computer graphics systems for visualization of pressure distribution and convective density particles; (7) design of a source code management system; (8) vectorizing incomplete conjugate gradient on the Cyber 203/205; (9) extensions of domain testing theory and; (10) performance analyzer for the pisces system.

Squeezed Back-to-Back Correlation of {D}^{0}{\\bar{D}}^{0} in Relativistic Heavy-Ion Collisions

NASA Astrophysics Data System (ADS)

Yang, Ai-Geng; Zhang, Yong; Cheng, Luan; Sun, Hao; Zhang, Wei-Ning

2018-05-01

We investigate the squeezed back-to-back correlation (BBC) of $D^0\\!{\\bar D}^0$ in relativistic heavy-ion collisions, using the in-medium mass modification calculated with a self-energy in hot pion gas and the source space-time distributions provided by the viscous hydrodynamic code VISH2+1. It is found that the BBC of $D^0\\!{\\bar D}^0$ is significant in peripheral Au+Au collisions at the RHIC energy. A possible way to detect the BBC in experiment is presented.

Evaluating Open-Source Full-Text Search Engines for Matching ICD-10 Codes.

PubMed

Jurcău, Daniel-Alexandru; Stoicu-Tivadar, Vasile

2016-01-01

This research presents the results of evaluating multiple free, open-source engines on matching ICD-10 diagnostic codes via full-text searches. The study investigates what it takes to get an accurate match when searching for a specific diagnostic code. For each code the evaluation starts by extracting the words that make up its text and continues with building full-text search queries from the combinations of these words. The queries are then run against all the ICD-10 codes until a match indicates the code in question as a match with the highest relative score. This method identifies the minimum number of words that must be provided in order for the search engines choose the desired entry. The engines analyzed include a popular Java-based full-text search engine, a lightweight engine written in JavaScript which can even execute on the user's browser, and two popular open-source relational database management systems.

Imaging of spatially extended hot spots with coded apertures for intra-operative nuclear medicine applications

NASA Astrophysics Data System (ADS)

Kaissas, I.; Papadimitropoulos, C.; Potiriadis, C.; Karafasoulis, K.; Loukas, D.; Lambropoulos, C. P.

2017-01-01

Coded aperture imaging transcends planar imaging with conventional collimators in efficiency and Field of View (FOV). We present experimental results for the detection of 141 keV and 122 keV γ-photons emitted by uniformly extended 99mTc and 57Co hot-spots along with simulations of uniformly and normally extended 99mTc hot-spots. These results prove that the method can be used for intra-operative imaging of radio-traced sentinel nodes and thyroid remnants. The study is performed using a setup of two gamma cameras, each consisting of a coded-aperture (or mask) of Modified Uniformly Redundant Array (MURA) of rank 19 positioned on top of a CdTe detector. The detector pixel pitch is 350 μm and its active area is 4.4 × 4.4 cm2, while the mask element size is 1.7 mm. The detectable photon energy ranges from 15 keV up to 200 keV with an energy resolution of 3-4 keV FWHM. Triangulation is exploited to estimate the 3D spatial coordinates of the radioactive spots within the system FOV. Two extended sources, with uniform distributed activity (11 and 24 mm in diameter, respectively), positioned at 16 cm from the system and with 3 cm distance between their centers, can be resolved and localized with accuracy better than 5%. The results indicate that the estimated positions of spatially extended sources lay within their volume size and that neighboring sources, even with a low level of radioactivity, such as 30 MBq, can be clearly distinguished with an acquisition time about 3 seconds.

Infrastructure Upgrades to Support Model Longevity and New Applications: The Variable Infiltration Capacity Model Version 5.0 (VIC 5.0)

NASA Astrophysics Data System (ADS)

Nijssen, B.; Hamman, J.; Bohn, T. J.

2015-12-01

The Variable Infiltration Capacity (VIC) model is a macro-scale semi-distributed hydrologic model. VIC development began in the early 1990s and it has been used extensively, applied from basin to global scales. VIC has been applied in a many use cases, including the construction of hydrologic data sets, trend analysis, data evaluation and assimilation, forecasting, coupled climate modeling, and climate change impact analysis. Ongoing applications of the VIC model include the University of Washington's drought monitor and forecast systems, and NASA's land data assimilation systems. The development of VIC version 5.0 focused on reconfiguring the legacy VIC source code to support a wider range of modern modeling applications. The VIC source code has been moved to a public Github repository to encourage participation by the model development community-at-large. The reconfiguration has separated the physical core of the model from the driver, which is responsible for memory allocation, pre- and post-processing and I/O. VIC 5.0 includes four drivers that use the same physical model core: classic, image, CESM, and Python. The classic driver supports legacy VIC configurations and runs in the traditional time-before-space configuration. The image driver includes a space-before-time configuration, netCDF I/O, and uses MPI for parallel processing. This configuration facilitates the direct coupling of streamflow routing, reservoir, and irrigation processes within VIC. The image driver is the foundation of the CESM driver; which couples VIC to CESM's CPL7 and a prognostic atmosphere. Finally, we have added a Python driver that provides access to the functions and datatypes of VIC's physical core from a Python interface. This presentation demonstrates how reconfiguring legacy source code extends the life and applicability of a research model.

GAMSOR: Gamma Source Preparation and DIF3D Flux Solution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, M. A.; Lee, C. H.; Hill, R. N.

2017-06-28

Nuclear reactors that rely upon the fission reaction have two modes of thermal energy deposition in the reactor system: neutron absorption and gamma absorption. The gamma rays are typically generated by neutron capture reactions or during the fission process which means the primary driver of energy production is of course the neutron interaction. In conventional reactor physics methods, the gamma heating component is ignored such that the gamma absorption is forced to occur at the gamma emission site. For experimental reactor systems like EBR-II and FFTF, the placement of structural pins and assemblies internal to the core leads to problemsmore » with power heating predictions because there is no fission power source internal to the assembly to dictate a spatial distribution of the power. As part of the EBR-II support work in the 1980s, the GAMSOR code was developed to assist analysts in calculating the gamma heating. The GAMSOR code is a modified version of DIF3D and actually functions within a sequence of DIF3D calculations. The gamma flux in a conventional fission reactor system does not perturb the neutron flux and thus the gamma flux calculation can be cast as a fixed source problem given a solution to the steady state neutron flux equation. This leads to a sequence of DIF3D calculations, called the GAMSOR sequence, which involves solving the neutron flux, then the gamma flux, and then combining the results to do a summary edit. In this manuscript, we go over the GAMSOR code and detail how it is put together and functions. We also discuss how to setup the GAMSOR sequence and input for each DIF3D calculation in the GAMSOR sequence.« less

Characterising RNA secondary structure space using information entropy

PubMed Central

2013-01-01

Comparative methods for RNA secondary structure prediction use evolutionary information from RNA alignments to increase prediction accuracy. The model is often described in terms of stochastic context-free grammars (SCFGs), which generate a probability distribution over secondary structures. It is, however, unclear how this probability distribution changes as a function of the input alignment. As prediction programs typically only return a single secondary structure, better characterisation of the underlying probability space of RNA secondary structures is of great interest. In this work, we show how to efficiently compute the information entropy of the probability distribution over RNA secondary structures produced for RNA alignments by a phylo-SCFG, and implement it for the PPfold model. We also discuss interpretations and applications of this quantity, including how it can clarify reasons for low prediction reliability scores. PPfold and its source code are available from http://birc.au.dk/software/ppfold/. PMID:23368905

Determination of spatial dose distribution in UCC treatments with LDR brachytherapy using Monte Carlo methods.

PubMed

Benites-Rengifo, Jorge Luis; Vega-Carrillo, Hector Rene

2018-05-19

Using Monte Carlos methods, with the MCNP5 code, a gynecological phantom and a vaginal cylinder were modeled. The spatial distribution of absorbed dose rates in Uterine Cervical Cancer treatment through low dose rate brachytherapy was determined. A liquid water gynecology computational phantom, including a vaginal cylinder applicator made of Lucite, was designed. The applicator has a linear array of four radioactive sources of Cesium 137. Around the vaginal cylinder, 13 water spherical cells of 0.5 cm-diameter were modeled to calculate absorbed dose emulating the procedure made by the treatment planning system. The gamma-ray fluence distribution was estimated, as well as the absorbed doses resulting approximately symmetrical for cells located at upper and lower of vaginal cylinder. Obtained results allow the use of the radioactive decay law to determine dose rate for Uterine Cervical Cancer using low dose rate brachytherapy. Copyright © 2018 Elsevier Ltd. All rights reserved.

Klusters, NeuroScope, NDManager: a free software suite for neurophysiological data processing and visualization.

PubMed

Hazan, Lynn; Zugaro, Michaël; Buzsáki, György

2006-09-15

Recent technological advances now allow for simultaneous recording of large populations of anatomically distributed neurons in behaving animals. The free software package described here was designed to help neurophysiologists process and view recorded data in an efficient and user-friendly manner. This package consists of several well-integrated applications, including NeuroScope (http://neuroscope.sourceforce.net), an advanced viewer for electrophysiological and behavioral data with limited editing capabilities, Klusters (http://klusters.sourceforge.net), a graphical cluster cutting application for manual and semi-automatic spike sorting, NDManager (GPL,see http://www.gnu.org/licenses/gpl.html), an experimental parameter and data processing manager. All of these programs are distributed under the GNU General Public License (GPL, see ), which gives its users legal permission to copy, distribute and/or modify the software. Also included are extensive user manuals and sample data, as well as source code and documentation.

Methods for Coding Tobacco-Related Twitter Data: A Systematic Review

PubMed Central

Unger, Jennifer B; Cruz, Tess Boley; Chu, Kar-Hai

2017-01-01

Background As Twitter has grown in popularity to 313 million monthly active users, researchers have increasingly been using it as a data source for tobacco-related research. Objective The objective of this systematic review was to assess the methodological approaches of categorically coded tobacco Twitter data and make recommendations for future studies. Methods Data sources included PsycINFO, Web of Science, PubMed, ABI/INFORM, Communication Source, and Tobacco Regulatory Science. Searches were limited to peer-reviewed journals and conference proceedings in English from January 2006 to July 2016. The initial search identified 274 articles using a Twitter keyword and a tobacco keyword. One coder reviewed all abstracts and identified 27 articles that met the following inclusion criteria: (1) original research, (2) focused on tobacco or a tobacco product, (3) analyzed Twitter data, and (4) coded Twitter data categorically. One coder extracted data collection and coding methods. Results E-cigarettes were the most common type of Twitter data analyzed, followed by specific tobacco campaigns. The most prevalent data sources were Gnip and Twitter’s Streaming application programming interface (API). The primary methods of coding were hand-coding and machine learning. The studies predominantly coded for relevance, sentiment, theme, user or account, and location of user. Conclusions Standards for data collection and coding should be developed to be able to more easily compare and replicate tobacco-related Twitter results. Additional recommendations include the following: sample Twitter’s databases multiple times, make a distinction between message attitude and emotional tone for sentiment, code images and URLs, and analyze user profiles. Being relatively novel and widely used among adolescents and black and Hispanic individuals, Twitter could provide a rich source of tobacco surveillance data among vulnerable populations. PMID:28363883

Aerodynamic and aeroacoustic for wind turbine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mohamed, Maizi; Rabah, Dizene

2015-03-10

This paper describes a hybrid approach forpredicting noise radiated from the rotating Wind Turbine (HAWT) blades, where the sources are extracted from an unsteady Reynolds-Averaged-Navier Stocks (URANS) simulation, ANSYS CFX 11.0, was used to calculate The near-field flow parameters around the blade surface that are necessary for FW-H codes. Comparisons with NREL Phase II experimental results are presented with respect to the pressure distributions for validating a capacity of the solver to calculate the near-field flow on and around the wind turbine blades, The results show that numerical data have a good agreement with experimental. The acoustic pressure, presented asmore » a sum of thickness and loading noise components, is analyzed by means of a discrete fast Fourier transformation for the presentation of the time acoustic time histories in the frequency domain. The results convincingly show that dipole source noise is the dominant noise source for this wind turbine.« less

Enabling three-dimensional densitometric measurements using laboratory source X-ray micro-computed tomography

NASA Astrophysics Data System (ADS)

Pankhurst, M. J.; Fowler, R.; Courtois, L.; Nonni, S.; Zuddas, F.; Atwood, R. C.; Davis, G. R.; Lee, P. D.

2018-01-01

We present new software allowing significantly improved quantitative mapping of the three-dimensional density distribution of objects using laboratory source polychromatic X-rays via a beam characterisation approach (c.f. filtering or comparison to phantoms). One key advantage is that a precise representation of the specimen material is not required. The method exploits well-established, widely available, non-destructive and increasingly accessible laboratory-source X-ray tomography. Beam characterisation is performed in two stages: (1) projection data are collected through a range of known materials utilising a novel hardware design integrated into the rotation stage; and (2) a Python code optimises a spectral response model of the system. We provide hardware designs for use with a rotation stage able to be tilted, yet the concept is easily adaptable to virtually any laboratory system and sample, and implicitly corrects the image artefact known as beam hardening.

Apollo: a community resource for genome annotation editing

PubMed Central

Ed, Lee; Nomi, Harris; Mark, Gibson; Raymond, Chetty; Suzanna, Lewis

2009-01-01

Summary: Apollo is a genome annotation-editing tool with an easy to use graphical interface. It is a component of the GMOD project, with ongoing development driven by the community. Recent additions to the software include support for the generic feature format version 3 (GFF3), continuous transcriptome data, a full Chado database interface, integration with remote services for on-the-fly BLAST and Primer BLAST analyses, graphical interfaces for configuring user preferences and full undo of all edit operations. Apollo's user community continues to grow, including its use as an educational tool for college and high-school students. Availability: Apollo is a Java application distributed under a free and open source license. Installers for Windows, Linux, Unix, Solaris and Mac OS X are available at http://apollo.berkeleybop.org, and the source code is available from the SourceForge CVS repository at http://gmod.cvs.sourceforge.net/gmod/apollo. Contact: elee@berkeleybop.org PMID:19439563

Apollo: a community resource for genome annotation editing.

PubMed

Lee, Ed; Harris, Nomi; Gibson, Mark; Chetty, Raymond; Lewis, Suzanna

2009-07-15

Apollo is a genome annotation-editing tool with an easy to use graphical interface. It is a component of the GMOD project, with ongoing development driven by the community. Recent additions to the software include support for the generic feature format version 3 (GFF3), continuous transcriptome data, a full Chado database interface, integration with remote services for on-the-fly BLAST and Primer BLAST analyses, graphical interfaces for configuring user preferences and full undo of all edit operations. Apollo's user community continues to grow, including its use as an educational tool for college and high-school students. Apollo is a Java application distributed under a free and open source license. Installers for Windows, Linux, Unix, Solaris and Mac OS X are available at http://apollo.berkeleybop.org, and the source code is available from the SourceForge CVS repository at http://gmod.cvs.sourceforge.net/gmod/apollo.

Investigation of Near Shannon Limit Coding Schemes

NASA Technical Reports Server (NTRS)

Kwatra, S. C.; Kim, J.; Mo, Fan

1999-01-01

Turbo codes can deliver performance that is very close to the Shannon limit. This report investigates algorithms for convolutional turbo codes and block turbo codes. Both coding schemes can achieve performance near Shannon limit. The performance of the schemes is obtained using computer simulations. There are three sections in this report. First section is the introduction. The fundamental knowledge about coding, block coding and convolutional coding is discussed. In the second section, the basic concepts of convolutional turbo codes are introduced and the performance of turbo codes, especially high rate turbo codes, is provided from the simulation results. After introducing all the parameters that help turbo codes achieve such a good performance, it is concluded that output weight distribution should be the main consideration in designing turbo codes. Based on the output weight distribution, the performance bounds for turbo codes are given. Then, the relationships between the output weight distribution and the factors like generator polynomial, interleaver and puncturing pattern are examined. The criterion for the best selection of system components is provided. The puncturing pattern algorithm is discussed in detail. Different puncturing patterns are compared for each high rate. For most of the high rate codes, the puncturing pattern does not show any significant effect on the code performance if pseudo - random interleaver is used in the system. For some special rate codes with poor performance, an alternative puncturing algorithm is designed which restores their performance close to the Shannon limit. Finally, in section three, for iterative decoding of block codes, the method of building trellis for block codes, the structure of the iterative decoding system and the calculation of extrinsic values are discussed.

TEMPEST code simulations of hydrogen distribution in reactor containment structures. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Trent, D.S.; Eyler, L.L.

The mass transport version of the TEMPEST computer code was used to simulate hydrogen distribution in geometric configurations relevant to reactor containment structures. Predicted results of Battelle-Frankfurt hydrogen distribution tests 1 to 6, and 12 are presented. Agreement between predictions and experimental data is good. Best agreement is obtained using the k-epsilon turbulence model in TEMPEST in flow cases where turbulent diffusion and stable stratification are dominant mechanisms affecting transport. The code's general analysis capabilities are summarized.

XMDS2: Fast, scalable simulation of coupled stochastic partial differential equations

NASA Astrophysics Data System (ADS)

Dennis, Graham R.; Hope, Joseph J.; Johnsson, Mattias T.

2013-01-01

XMDS2 is a cross-platform, GPL-licensed, open source package for numerically integrating initial value problems that range from a single ordinary differential equation up to systems of coupled stochastic partial differential equations. The equations are described in a high-level XML-based script, and the package generates low-level optionally parallelised C++ code for the efficient solution of those equations. It combines the advantages of high-level simulations, namely fast and low-error development, with the speed, portability and scalability of hand-written code. XMDS2 is a complete redesign of the XMDS package, and features support for a much wider problem space while also producing faster code. Program summaryProgram title: XMDS2 Catalogue identifier: AENK_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AENK_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: GNU General Public License, version 2 No. of lines in distributed program, including test data, etc.: 872490 No. of bytes in distributed program, including test data, etc.: 45522370 Distribution format: tar.gz Programming language: Python and C++. Computer: Any computer with a Unix-like system, a C++ compiler and Python. Operating system: Any Unix-like system; developed under Mac OS X and GNU/Linux. RAM: Problem dependent (roughly 50 bytes per grid point) Classification: 4.3, 6.5. External routines: The external libraries required are problem-dependent. Uses FFTW3 Fourier transforms (used only for FFT-based spectral methods), dSFMT random number generation (used only for stochastic problems), MPI message-passing interface (used only for distributed problems), HDF5, GNU Scientific Library (used only for Bessel-based spectral methods) and a BLAS implementation (used only for non-FFT-based spectral methods). Nature of problem: General coupled initial-value stochastic partial differential equations. Solution method: Spectral method with method-of-lines integration Running time: Determined by the size of the problem

Aquarius Project: Research in the System Architecture of Accelerators for the High Performance Execution of Logic Programs.

DTIC Science & Technology

1991-05-31

benchmarks ............ .... . .. .. . . .. 220 Appendix G : Source code of the Aquarius Prolog compiler ........ . 224 Chapter I Introduction "You’re given...notation, a tool that is used throughout the compiler’s implementation. Appendix F lists the source code of the C and Prolog benchmarks. Appendix G lists the...source code of the compilcr. 5 "- standard form Prolog / a-sfomadon / head umrvln Convert to tmeikernel Prol g vrans~fonaon 1symbolic execution

Building a Snow Data Management System using Open Source Software (and IDL)

NASA Astrophysics Data System (ADS)

Goodale, C. E.; Mattmann, C. A.; Ramirez, P.; Hart, A. F.; Painter, T.; Zimdars, P. A.; Bryant, A.; Brodzik, M.; Skiles, M.; Seidel, F. C.; Rittger, K. E.

2012-12-01

At NASA's Jet Propulsion Laboratory free and open source software is used everyday to support a wide range of projects, from planetary to climate to research and development. In this abstract I will discuss the key role that open source software has played in building a robust science data processing pipeline for snow hydrology research, and how the system is also able to leverage programs written in IDL, making JPL's Snow Data System a hybrid of open source and proprietary software. Main Points: - The Design of the Snow Data System (illustrate how the collection of sub-systems are combined to create a complete data processing pipeline) - Discuss the Challenges of moving from a single algorithm on a laptop, to running 100's of parallel algorithms on a cluster of servers (lesson's learned) - Code changes - Software license related challenges - Storage Requirements - System Evolution (from data archiving, to data processing, to data on a map, to near-real-time products and maps) - Road map for the next 6 months (including how easily we re-used the snowDS code base to support the Airborne Snow Observatory Mission) Software in Use and their Software Licenses: IDL - Used for pre and post processing of data. Licensed under a proprietary software license held by Excelis. Apache OODT - Used for data management and workflow processing. Licensed under the Apache License Version 2. GDAL - Geospatial Data processing library used for data re-projection currently. Licensed under the X/MIT license. GeoServer - WMS Server. Licensed under the General Public License Version 2.0 Leaflet.js - Javascript web mapping library. Licensed under the Berkeley Software Distribution License. Python - Glue code and miscellaneous data processing support. Licensed under the Python Software Foundation License. Perl - Script wrapper for running the SCAG algorithm. Licensed under the General Public License Version 3. PHP - Front-end web application programming. Licensed under the PHP License Version 3.01

Developing CORBA-Based Distributed Scientific Applications from Legacy Fortran Programs

NASA Technical Reports Server (NTRS)

Sang, Janche; Kim, Chan; Lopez, Isaac

2000-01-01

Recent progress in distributed object technology has enabled software applications to be developed and deployed easily such that objects or components can work together across the boundaries of the network, different operating systems, and different languages. A distributed object is not necessarily a complete application but rather a reusable, self-contained piece of software that co-operates with other objects in a plug-and-play fashion via a well-defined interface. The Common Object Request Broker Architecture (CORBA), a middleware standard defined by the Object Management Group (OMG), uses the Interface Definition Language (IDL) to specify such an interface for transparent communication between distributed objects. Since IDL can be mapped to any programming language, such as C++, Java, Smalltalk, etc., existing applications can be integrated into a new application and hence the tasks of code re-writing and software maintenance can be reduced. Many scientific applications in aerodynamics and solid mechanics are written in Fortran. Refitting these legacy Fortran codes with CORBA objects can increase the codes reusability. For example, scientists could link their scientific applications to vintage Fortran programs such as Partial Differential Equation(PDE) solvers in a plug-and-play fashion. Unfortunately, CORBA IDL to Fortran mapping has not been proposed and there seems to be no direct method of generating CORBA objects from Fortran without having to resort to manually writing C/C++ wrappers. In this paper, we present an efficient methodology to integrate Fortran legacy programs into a distributed object framework. Issues and strategies regarding the conversion and decomposition of Fortran codes into CORBA objects are discussed. The following diagram shows the conversion and decomposition mechanism we proposed. Our goal is to keep the Fortran codes unmodified. The conversion- aided tool takes the Fortran application program as input and helps programmers generate C/C++ header file and IDL file for wrapping the Fortran code. Programmers need to determine by themselves how to decompose the legacy application into several reusable components based on the cohesion and coupling factors among the functions and subroutines. However, programming effort still can be greatly reduced because function headings and types have been converted to C++ and IDL styles. Most Fortran applications use the COMMON block to facilitate the transfer of large amount of variables among several functions. The COMMON block plays the similar role of global variables used in C. In the CORBA-compliant programming environment, global variables can not be used to pass values between objects. One approach to dealing with this problem is to put the COMMON variables into the parameter list. We do not adopt this approach because it requires modification of the Fortran source code which violates our design consideration. Our approach is to extract the COMMON blocks and convert them into a structure-typed attribute in C++. Through attributes, each component can initialize the variables and return the computation result back to the client. We have tested successfully the proposed conversion methodology based on the f2c converter. Since f2c only translates Fortran to C, we still needed to edit the converted code to meet the C++ and IDL syntax. For example, C++/IDL requires a tag in the structure type, while C does not. In this paper, we identify the necessary changes to the f2c converter in order to directly generate the C++ header and the IDL file. Our future work is to add GUI interface to ease the decomposition task by simply dragging and dropping icons.

MEMOPS: data modelling and automatic code generation.

PubMed

Fogh, Rasmus H; Boucher, Wayne; Ionides, John M C; Vranken, Wim F; Stevens, Tim J; Laue, Ernest D

2010-03-25

In recent years the amount of biological data has exploded to the point where much useful information can only be extracted by complex computational analyses. Such analyses are greatly facilitated by metadata standards, both in terms of the ability to compare data originating from different sources, and in terms of exchanging data in standard forms, e.g. when running processes on a distributed computing infrastructure. However, standards thrive on stability whereas science tends to constantly move, with new methods being developed and old ones modified. Therefore maintaining both metadata standards, and all the code that is required to make them useful, is a non-trivial problem. Memops is a framework that uses an abstract definition of the metadata (described in UML) to generate internal data structures and subroutine libraries for data access (application programming interfaces--APIs--currently in Python, C and Java) and data storage (in XML files or databases). For the individual project these libraries obviate the need for writing code for input parsing, validity checking or output. Memops also ensures that the code is always internally consistent, massively reducing the need for code reorganisation. Across a scientific domain a Memops-supported data model makes it easier to support complex standards that can capture all the data produced in a scientific area, share them among all programs in a complex software pipeline, and carry them forward to deposition in an archive. The principles behind the Memops generation code will be presented, along with example applications in Nuclear Magnetic Resonance (NMR) spectroscopy and structural biology.

Opening up Architectures of Software-Intensive Systems: A Functional Decomposition to Support System Comprehension

DTIC Science & Technology

2007-10-01

Architecture ................................................................................ 14 Figure 2. Eclipse Java Model...16 Figure 3. Eclipse Java Model at the Source Code Level...24 Figure 9. Java Source Code

Diffusive deposition of aerosols in Phebus containment during FPT-2 test

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kontautas, A.; Urbonavicius, E.

2012-07-01

At present the lumped-parameter codes is the main tool to investigate the complex response of the containment of Nuclear Power Plant in case of an accident. Continuous development and validation of the codes is required to perform realistic investigation of the processes that determine the possible source term of radioactive products to the environment. Validation of the codes is based on the comparison of the calculated results with the measurements performed in experimental facilities. The most extensive experimental program to investigate fission product release from the molten fuel, transport through the cooling circuit and deposition in the containment is performedmore » in PHEBUS test facility. Test FPT-2 performed in this facility is considered for analysis of processes taking place in containment. Earlier performed investigations using COCOSYS code showed that the code could be successfully used for analysis of thermal-hydraulic processes and deposition of aerosols, but there was also noticed that diffusive deposition on the vertical walls does not fit well with the measured results. In the CPA module of ASTEC code there is implemented different model for diffusive deposition, therefore the PHEBUS containment model was transferred from COCOSYS code to ASTEC-CPA to investigate the influence of the diffusive deposition modelling. Analysis was performed using PHEBUS containment model of 16 nodes. The calculated thermal-hydraulic parameters are in good agreement with measured results, which gives basis for realistic simulation of aerosol transport and deposition processes. Performed investigations showed that diffusive deposition model has influence on the aerosol deposition distribution on different surfaces in the test facility. (authors)« less

Scalable Video Transmission Over Multi-Rate Multiple Access Channels

DTIC Science & Technology

2007-06-01

Rate - compatible punctured convolutional codes (RCPC codes ) and their ap- plications,” IEEE...source encoded using the MPEG-4 video codec. The source encoded bitstream is then channel encoded with Rate Compatible Punctured Convolutional (RCPC...Clark, and J. M. Geist, “ Punctured convolutional codes or rate (n-1)/n and simplified maximum likelihood decoding,” IEEE Transactions on

Comparison of TG‐43 dosimetric parameters of brachytherapy sources obtained by three different versions of MCNP codes

PubMed Central

Zaker, Neda; Sina, Sedigheh; Koontz, Craig; Meigooni1, Ali S.

2016-01-01

Monte Carlo simulations are widely used for calculation of the dosimetric parameters of brachytherapy sources. MCNP4C2, MCNP5, MCNPX, EGS4, EGSnrc, PTRAN, and GEANT4 are among the most commonly used codes in this field. Each of these codes utilizes a cross‐sectional library for the purpose of simulating different elements and materials with complex chemical compositions. The accuracies of the final outcomes of these simulations are very sensitive to the accuracies of the cross‐sectional libraries. Several investigators have shown that inaccuracies of some of the cross section files have led to errors in  125I and  103Pd parameters. The purpose of this study is to compare the dosimetric parameters of sample brachytherapy sources, calculated with three different versions of the MCNP code — MCNP4C, MCNP5, and MCNPX. In these simulations for each source type, the source and phantom geometries, as well as the number of the photons, were kept identical, thus eliminating the possible uncertainties. The results of these investigations indicate that for low‐energy sources such as  125I and  103Pd there are discrepancies in gL(r) values. Discrepancies up to 21.7% and 28% are observed between MCNP4C and other codes at a distance of 6 cm for  103Pd and 10 cm for  125I from the source, respectively. However, for higher energy sources, the discrepancies in gL(r) values are less than 1.1% for  192Ir and less than 1.2% for  137Cs between the three codes. PACS number(s): 87.56.bg PMID:27074460

Monte Carlo simulation of radiation transport and dose deposition from locally released gold nanoparticles labeled with 111In, 177Lu or 90Y incorporated into tissue implantable depots

NASA Astrophysics Data System (ADS)

Lai, Priscilla; Cai, Zhongli; Pignol, Jean-Philippe; Lechtman, Eli; Mashouf, Shahram; Lu, Yijie; Winnik, Mitchell A.; Jaffray, David A.; Reilly, Raymond M.

2017-11-01

Permanent seed implantation (PSI) brachytherapy is a highly conformal form of radiation therapy but is challenged with dose inhomogeneity due to its utilization of low energy radiation sources. Gold nanoparticles (AuNP) conjugated with electron emitting radionuclides have recently been developed as a novel form of brachytherapy and can aid in homogenizing dose through physical distribution of radiolabeled AuNP when injected intratumorally (IT) in suspension. However, the distribution is unpredictable and precise placement of many injections would be difficult. Previously, we reported the design of a nanoparticle depot (NPD) that can be implanted using PSI techniques and which facilitates controlled release of AuNP. We report here the 3D dose distribution resulting from a NPD incorporating AuNP labeled with electron emitters (90Y, 177Lu, 111In) of different energies using Monte Carlo based voxel level dosimetry. The MCNP5 Monte Carlo radiation transport code was used to assess differences in dose distribution from simulated NPD and conventional brachytherapy sources, positioned in breast tissue simulating material. We further compare these dose distributions in mice bearing subcutaneous human breast cancer xenografts implanted with 177Lu-AuNP NPD, or injected IT with 177Lu-AuNP in suspension. The radioactivity distributions were derived from registered SPECT/CT images and time-dependent dose was estimated. Results demonstrated that the dose distribution from NPD reduced the maximum dose 3-fold when compared to conventional seeds. For simulated NPD, as well as NPD implanted in vivo, 90Y delivered the most homogeneous dose distribution. The tumor radioactivity in mice IT injected with 177Lu-AuNP redistributed while radioactivity in the NPD remained confined to the implant site. The dose distribution from radiolabeled AuNP NPD were predictable and concentric in contrast to IT injected radiolabeled AuNP, which provided irregular and temporally variant dose distributions. The use of NPD may serve as an intermediate between PSI and radiation delivered by radiolabeled AuNP by providing a controlled method to improve delivery of prescribed doses as well as homogenize dose from low penetrating electron sources.

Aspect-Oriented Programming

NASA Technical Reports Server (NTRS)

Elrad, Tzilla (Editor); Filman, Robert E. (Editor); Bader, Atef (Editor)

2001-01-01

Computer science has experienced an evolution in programming languages and systems from the crude assembly and machine codes of the earliest computers through concepts such as formula translation, procedural programming, structured programming, functional programming, logic programming, and programming with abstract data types. Each of these steps in programming technology has advanced our ability to achieve clear separation of concerns at the source code level. Currently, the dominant programming paradigm is object-oriented programming - the idea that one builds a software system by decomposing a problem into objects and then writing the code of those objects. Such objects abstract together behavior and data into a single conceptual and physical entity. Object-orientation is reflected in the entire spectrum of current software development methodologies and tools - we have OO methodologies, analysis and design tools, and OO programming languages. Writing complex applications such as graphical user interfaces, operating systems, and distributed applications while maintaining comprehensible source code has been made possible with OOP. Success at developing simpler systems leads to aspirations for greater complexity. Object orientation is a clever idea, but has certain limitations. We are now seeing that many requirements do not decompose neatly into behavior centered on a single locus. Object technology has difficulty localizing concerns invoking global constraints and pandemic behaviors, appropriately segregating concerns, and applying domain-specific knowledge. Post-object programming (POP) mechanisms that look to increase the expressiveness of the OO paradigm are a fertile arena for current research. Examples of POP technologies include domain-specific languages, generative programming, generic programming, constraint languages, reflection and metaprogramming, feature-oriented development, views/viewpoints, and asynchronous message brokering. (Czarneclu and Eisenecker s book includes a good survey of many of these technologies).

Knowledge management: Role of the the Radiation Safety Information Computational Center (RSICC)

NASA Astrophysics Data System (ADS)

Valentine, Timothy

2017-09-01

The Radiation Safety Information Computational Center (RSICC) at Oak Ridge National Laboratory (ORNL) is an information analysis center that collects, archives, evaluates, synthesizes and distributes information, data and codes that are used in various nuclear technology applications. RSICC retains more than 2,000 software packages that have been provided by code developers from various federal and international agencies. RSICC's customers (scientists, engineers, and students from around the world) obtain access to such computing codes (source and/or executable versions) and processed nuclear data files to promote on-going research, to ensure nuclear and radiological safety, and to advance nuclear technology. The role of such information analysis centers is critical for supporting and sustaining nuclear education and training programs both domestically and internationally, as the majority of RSICC's customers are students attending U.S. universities. Additionally, RSICC operates a secure CLOUD computing system to provide access to sensitive export-controlled modeling and simulation (M&S) tools that support both domestic and international activities. This presentation will provide a general review of RSICC's activities, services, and systems that support knowledge management and education and training in the nuclear field.

Coding conventions and principles for a National Land-Change Modeling Framework

USGS Publications Warehouse

Donato, David I.

2017-07-14

This report establishes specific rules for writing computer source code for use with the National Land-Change Modeling Framework (NLCMF). These specific rules consist of conventions and principles for writing code primarily in the C and C++ programming languages. Collectively, these coding conventions and coding principles create an NLCMF programming style. In addition to detailed naming conventions, this report provides general coding conventions and principles intended to facilitate the development of high-performance software implemented with code that is extensible, flexible, and interoperable. Conventions for developing modular code are explained in general terms and also enabled and demonstrated through the appended templates for C++ base source-code and header files. The NLCMF limited-extern approach to module structure, code inclusion, and cross-module access to data is both explained in the text and then illustrated through the module templates. Advice on the use of global variables is provided.

A multiphysics and multiscale software environment for modeling astrophysical systems

NASA Astrophysics Data System (ADS)

Portegies Zwart, Simon; McMillan, Steve; Harfst, Stefan; Groen, Derek; Fujii, Michiko; Nualláin, Breanndán Ó.; Glebbeek, Evert; Heggie, Douglas; Lombardi, James; Hut, Piet; Angelou, Vangelis; Banerjee, Sambaran; Belkus, Houria; Fragos, Tassos; Fregeau, John; Gaburov, Evghenii; Izzard, Rob; Jurić, Mario; Justham, Stephen; Sottoriva, Andrea; Teuben, Peter; van Bever, Joris; Yaron, Ofer; Zemp, Marcel

2009-05-01

We present MUSE, a software framework for combining existing computational tools for different astrophysical domains into a single multiphysics, multiscale application. MUSE facilitates the coupling of existing codes written in different languages by providing inter-language tools and by specifying an interface between each module and the framework that represents a balance between generality and computational efficiency. This approach allows scientists to use combinations of codes to solve highly coupled problems without the need to write new codes for other domains or significantly alter their existing codes. MUSE currently incorporates the domains of stellar dynamics, stellar evolution and stellar hydrodynamics for studying generalized stellar systems. We have now reached a "Noah's Ark" milestone, with (at least) two available numerical solvers for each domain. MUSE can treat multiscale and multiphysics systems in which the time- and size-scales are well separated, like simulating the evolution of planetary systems, small stellar associations, dense stellar clusters, galaxies and galactic nuclei. In this paper we describe three examples calculated using MUSE: the merger of two galaxies, the merger of two evolving stars, and a hybrid N-body simulation. In addition, we demonstrate an implementation of MUSE on a distributed computer which may also include special-purpose hardware, such as GRAPEs or GPUs, to accelerate computations. The current MUSE code base is publicly available as open source at http://muse.li.

Status and future of MUSE

NASA Astrophysics Data System (ADS)

Harfst, S.; Portegies Zwart, S.; McMillan, S.

2008-12-01

We present MUSE, a software framework for combining existing computational tools from different astrophysical domains into a single multi-physics, multi-scale application. MUSE facilitates the coupling of existing codes written in different languages by providing inter-language tools and by specifying an interface between each module and the framework that represents a balance between generality and computational efficiency. This approach allows scientists to use combinations of codes to solve highly-coupled problems without the need to write new codes for other domains or significantly alter their existing codes. MUSE currently incorporates the domains of stellar dynamics, stellar evolution and stellar hydrodynamics for studying generalized stellar systems. We have now reached a ``Noah's Ark'' milestone, with (at least) two available numerical solvers for each domain. MUSE can treat multi-scale and multi-physics systems in which the time- and size-scales are well separated, like simulating the evolution of planetary systems, small stellar associations, dense stellar clusters, galaxies and galactic nuclei. In this paper we describe two examples calculated using MUSE: the merger of two galaxies and an N-body simulation with live stellar evolution. In addition, we demonstrate an implementation of MUSE on a distributed computer which may also include special-purpose hardware, such as GRAPEs or GPUs, to accelerate computations. The current MUSE code base is publicly available as open source at http://muse.li.