Design for approaching Cicada-wing reflectance in low- and high-index biomimetic nanostructures.

PubMed

Huang, Yi-Fan; Jen, Yi-Jun; Chen, Li-Chyong; Chen, Kuei-Hsien; Chattopadhyay, Surojit

2015-01-27

Natural nanostructures in low refractive index Cicada wings demonstrate ≤ 1% reflectance over the visible spectrum. We provide design parameters for Cicada-wing-inspired nanotip arrays as efficient light harvesters over a 300-1000 nm spectrum and up to 60° angle of incidence in both low-index, such as silica and indium tin oxide, and high-index, such as silicon and germanium, photovoltaic materials. Biomimicry of the Cicada wing design, demonstrating gradient index, onto these material surfaces, either by real electron cyclotron resonance microwave plasma processing or by modeling, was carried out to achieve a target reflectance of ∼ 1%. Design parameters of spacing/wavelength and length/spacing fitted into a finite difference time domain model could simulate the experimental reflectance values observed in real silicon and germanium or in model silica and indium tin oxide nanotip arrays. A theoretical mapping of the length/spacing and spacing/wavelength space over varied refractive index materials predicts that lengths of ∼ 1.5 μm and spacings of ∼ 200 nm in high-index and lengths of ∼ 200-600 nm and spacings of ∼ 100-400 nm in low-index materials would exhibit ≤ 1% target reflectance and ∼ 99% optical absorption over the entire UV-vis region and angle of incidence up to 60°.

Application of kernel functions for accurate similarity search in large chemical databases.

PubMed

Wang, Xiaohong; Huan, Jun; Smalter, Aaron; Lushington, Gerald H

2010-04-29

Similarity search in chemical structure databases is an important problem with many applications in chemical genomics, drug design, and efficient chemical probe screening among others. It is widely believed that structure based methods provide an efficient way to do the query. Recently various graph kernel functions have been designed to capture the intrinsic similarity of graphs. Though successful in constructing accurate predictive and classification models, graph kernel functions can not be applied to large chemical compound database due to the high computational complexity and the difficulties in indexing similarity search for large databases. To bridge graph kernel function and similarity search in chemical databases, we applied a novel kernel-based similarity measurement, developed in our team, to measure similarity of graph represented chemicals. In our method, we utilize a hash table to support new graph kernel function definition, efficient storage and fast search. We have applied our method, named G-hash, to large chemical databases. Our results show that the G-hash method achieves state-of-the-art performance for k-nearest neighbor (k-NN) classification. Moreover, the similarity measurement and the index structure is scalable to large chemical databases with smaller indexing size, and faster query processing time as compared to state-of-the-art indexing methods such as Daylight fingerprints, C-tree and GraphGrep. Efficient similarity query processing method for large chemical databases is challenging since we need to balance running time efficiency and similarity search accuracy. Our previous similarity search method, G-hash, provides a new way to perform similarity search in chemical databases. Experimental study validates the utility of G-hash in chemical databases.

Cardiorespiratory endurance evaluation using heart rate analysis during ski simulator exercise and the Harvard step test in elementary school students.

PubMed

Lee, Hyo Taek; Roh, Hyo Lyun; Kim, Yoon Sang

2016-01-01

[Purpose] Efficient management using exercise programs with various benefits should be provided by educational institutions for children in their growth phase. We analyzed the heart rates of children during ski simulator exercise and the Harvard step test to evaluate the cardiopulmonary endurance by calculating their post-exercise recovery rate. [Subjects and Methods] The subjects (n = 77) were categorized into a normal weight and an overweight/obesity group by body mass index. They performed each exercise for 3 minutes. The cardiorespiratory endurance was calculated using the Physical Efficiency Index formula. [Results] The ski simulator and Harvard step test showed that there was a significant difference in the heart rates of the 2 body mass index-based groups at each minute. The normal weight and the ski-simulator group had higher Physical Efficiency Index levels. [Conclusion] This study showed that a simulator exercise can produce a cumulative load even when performed at low intensity, and can be effectively utilized as exercise equipment since it resulted in higher Physical Efficiency Index levels than the Harvard step test. If schools can increase sport durability by stimulating students' interests, the ski simulator exercise can be used in programs designed to improve and strengthen students' physical fitness.

Design and experimental evidence of a flat graded-index photonic crystal lens

NASA Astrophysics Data System (ADS)

Gaufillet, F.; Akmansoy, É.

2013-08-01

We report on the design and the experimental evidence of a flat graded index photonic crystal lens. The gradient has been designed so that the flat slab focuses a plane wave and so that it converts the wave issued from a point source into a plane wave. This graded-index photonic crystal lens operates as a convex lens. The gradient of index results from varying the filling factor of the photonic crystal in the direction perpendicular to that of the propagation of the electromagnetic field. The shape of the gradient of index has been designed by engineering the iso-frequency curves of the photonic crystal. As only a few layers were necessary and as graded photonic crystals may be fabricated by a variety of processes, this shows the ability of graded photonic crystals to efficiently apply for various photonic devices, from microwave range to the optical domain. 42.70.Qs Photonic bandgap materials, 78.67.Pt Optical properties of photonic structures, 41.20.Jb Electromagnetic wave propagation; radiowave propagation 84.40.Ba Antennas.

Design, simulation, and optimization of an RGB polarization independent transmission volume hologram

NASA Astrophysics Data System (ADS)

Mahamat, Adoum Hassan

Volume phase holographic (VPH) gratings have been designed for use in many areas of science and technology such as optical communication, medical imaging, spectroscopy and astronomy. The goal of this dissertation is to design a volume phase holographic grating that provides diffraction efficiencies of at least 70% for the entire visible wavelengths and higher than 90% for red, green, and blue light when the incident light is unpolarized. First, the complete design, simulation and optimization of the volume hologram are presented. The optimization is done using a Monte Carlo analysis to solve for the index modulation needed to provide higher diffraction efficiencies. The solutions are determined by solving the diffraction efficiency equations determined by Kogelnik's two wave coupled-wave theory. The hologram is further optimized using the rigorous coupled-wave analysis to correct for effects of absorption omitted by Kogelnik's method. Second, the fabrication or recording process of the volume hologram is described in detail. The active region of the volume hologram is created by interference of two coherent beams within the thin film. Third, the experimental set up and measurement of some properties including the diffraction efficiencies of the volume hologram, and the thickness of the active region are conducted. Fourth, the polarimetric response of the volume hologram is investigated. The polarization study is developed to provide insight into the effect of the refractive index modulation onto the polarization state and diffraction efficiency of incident light.

Unidirectional transmission using array of zero-refractive-index metamaterials

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

Fu, Yangyang; Xu, Lin; Hong Hang, Zhi

2014-05-12

In this Letter, we find that high efficient unidirectional transmission occurs for an array of prisms made of zero-refractive-index metamaterials. As a specific demonstration, we further design the device using Dirac-cone-like photonic crystals. The device can function for a broadband of spectrum. Numerical simulations are performed to verify the one-way wave functionality.

High-performance slow light photonic crystal waveguides with topology optimized or circular-hole based material layouts

NASA Astrophysics Data System (ADS)

Wang, Fengwen; Jensen, Jakob S.; Sigmund, Ole

2012-10-01

Photonic crystal waveguides are optimized for modal confinement and loss related to slow light with high group index. A detailed comparison between optimized circular-hole based waveguides and optimized waveguides with free topology is performed. Design robustness with respect to manufacturing imperfections is enforced by considering different design realizations generated from under-, standard- and over-etching processes in the optimization procedure. A constraint ensures a certain modal confinement, and loss related to slow light with high group index is indirectly treated by penalizing field energy located in air regions. It is demonstrated that slow light with a group index up to ng = 278 can be achieved by topology optimized waveguides with promising modal confinement and restricted group-velocity-dispersion. All the topology optimized waveguides achieve a normalized group-index bandwidth of 0.48 or above. The comparisons between circular-hole based designs and topology optimized designs illustrate that the former can be efficient for dispersion engineering but that larger improvements are possible if irregular geometries are allowed.

Retrospective indexing (RI) - A computer-aided indexing technique

NASA Technical Reports Server (NTRS)

Buchan, Ronald L.

1990-01-01

An account is given of a method for data base-updating designated 'computer-aided indexing' (CAI) which has been very efficiently implemented at NASA's Scientific and Technical Information Facility by means of retrospective indexing. Novel terms added to the NASA Thesaurus will therefore proceed directly into both the NASA-RECON aerospace information system and its portion of the ESA-Information Retrieval Service, giving users full access to material thus indexed. If a given term appears in the title of a record, it is given special weight. An illustrative graphic representation of the CAI search strategy is presented.

DOGMA: A Disk-Oriented Graph Matching Algorithm for RDF Databases

NASA Astrophysics Data System (ADS)

Bröcheler, Matthias; Pugliese, Andrea; Subrahmanian, V. S.

RDF is an increasingly important paradigm for the representation of information on the Web. As RDF databases increase in size to approach tens of millions of triples, and as sophisticated graph matching queries expressible in languages like SPARQL become increasingly important, scalability becomes an issue. To date, there is no graph-based indexing method for RDF data where the index was designed in a way that makes it disk-resident. There is therefore a growing need for indexes that can operate efficiently when the index itself resides on disk. In this paper, we first propose the DOGMA index for fast subgraph matching on disk and then develop a basic algorithm to answer queries over this index. This algorithm is then significantly sped up via an optimized algorithm that uses efficient (but correct) pruning strategies when combined with two different extensions of the index. We have implemented a preliminary system and tested it against four existing RDF database systems developed by others. Our experiments show that our algorithm performs very well compared to these systems, with orders of magnitude improvements for complex graph queries.

Multilayer dielectric diffraction gratings

DOEpatents

Perry, Michael D.; Britten, Jerald A.; Nguyen, Hoang T.; Boyd, Robert; Shore, Bruce W.

1999-01-01

The design and fabrication of dielectric grating structures with high diffraction efficiency used in reflection or transmission is described. By forming a multilayer structure of alternating index dielectric materials and placing a grating structure on top of the multilayer, a diffraction grating of adjustable efficiency, and variable optical bandwidth can be obtained. Diffraction efficiency into the first order in reflection varying between 1 and 98 percent has been achieved by controlling the design of the multilayer and the depth, shape, and material comprising the grooves of the grating structure. Methods for fabricating these gratings without the use of ion etching techniques are described.

Multilayer dielectric diffraction gratings

DOEpatents

Perry, M.D.; Britten, J.A.; Nguyen, H.T.; Boyd, R.; Shore, B.W.

1999-05-25

The design and fabrication of dielectric grating structures with high diffraction efficiency used in reflection or transmission is described. By forming a multilayer structure of alternating index dielectric materials and placing a grating structure on top of the multilayer, a diffraction grating of adjustable efficiency, and variable optical bandwidth can be obtained. Diffraction efficiency into the first order in reflection varying between 1 and 98 percent has been achieved by controlling the design of the multilayer and the depth, shape, and material comprising the grooves of the grating structure. Methods for fabricating these gratings without the use of ion etching techniques are described. 7 figs.

Control Synthesis of Discrete-Time T-S Fuzzy Systems: Reducing the Conservatism Whilst Alleviating the Computational Burden.

PubMed

Xie, Xiangpeng; Yue, Dong; Zhang, Huaguang; Peng, Chen

2017-09-01

The augmented multi-indexed matrix approach acts as a powerful tool in reducing the conservatism of control synthesis of discrete-time Takagi-Sugeno fuzzy systems. However, its computational burden is sometimes too heavy as a tradeoff. Nowadays, reducing the conservatism whilst alleviating the computational burden becomes an ideal but very challenging problem. This paper is toward finding an efficient way to achieve one of satisfactory answers. Different from the augmented multi-indexed matrix approach in the literature, we aim to design a more efficient slack variable approach under a general framework of homogenous matrix polynomials. Thanks to the introduction of a new extended representation for homogeneous matrix polynomials, related matrices with the same coefficient are collected together into one sole set and thus those redundant terms of the augmented multi-indexed matrix approach can be removed, i.e., the computational burden can be alleviated in this paper. More importantly, due to the fact that more useful information is involved into control design, the conservatism of the proposed approach as well is less than the counterpart of the augmented multi-indexed matrix approach. Finally, numerical experiments are given to show the effectiveness of the proposed approach.

Energetic-environmental-economic assessment of the biogas system with three utilization pathways: Combined heat and power, biomethane and fuel cell.

PubMed

Wu, Bin; Zhang, Xiangping; Shang, Dawei; Bao, Di; Zhang, Suojiang; Zheng, Tao

2016-08-01

A typical biogas system with three utilization pathways, i.e., biogas upgrading, biogas combined heat and power (CHP), biogas solid oxide fuel cells (SOFCs) were designed. It was assessed from the viewpoint of energy, environment and economy by using energy efficiency, green degree and net present value index respectively. The assessment considered the trade-off relationships among these indexes, which is more comprehensive than previous systematic evaluation work only included single or two of the pathway(s) by using one or two of the index(es). Assessment results indicated that biogas upgrading pathway has the highest systematic energy efficiency (46.5%) and shortest payback period (8.9year) with the green degree production is the lowest (9.29gd/day). While for biogas SOFC pathway, although the green degree production is the highest (21.77gd/day), the payback period is longer (14.5year) and the energy efficiency is 13.6% lower than the biogas upgrading pathway. Copyright © 2016 Elsevier Ltd. All rights reserved.

One-way acoustic mirror based on anisotropic zero-index media

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

Gu, Zhong-ming; Liang, Bin, E-mail: liangbin@nju.edu.cn, E-mail: jccheng@nju.edu.cn; Yang, Jing

2015-11-23

We have designed a one-way acoustic mirror comprising anisotropic zero-index media. For acoustic beam incident at a particular angle, the designed structure behaves like a high-efficient mirror that redirects almost all the incident energy into another direction predicted by the Snell's law, while becoming virtually transparent to beams propagating reversely along this output path. Furthermore, the mirror can be tailored to work at arbitrary incident angle by simply adjusting its geometry. Our design, with undirectional reflection functionality and flexible working angle, may offer possibilities in space isolations and have deep implication in various scenarios like ultrasound imaging or noise control.

Monolithic subwavelength high refractive-index-contrast grating VCSELs

NASA Astrophysics Data System (ADS)

Gebski, Marcin; Dems, Maciej; Lott, James A.; Czyszanowski, Tomasz

2016-03-01

In this paper we present optical design and simulation results of vertical-cavity surface-emitting lasers (VCSELs) that incorporate monolithic subwavelength high refractive-index-contrast grating (MHCG) mirrors - a new variety of HCG mirror that is composed of high index material surrounded only on one side by low index material. We show the impact of an MHCG mirror on the performance of 980 nm VCSELs designed for high bit rate and energy-efficient optical data communications. In our design, all or part of the all-semiconductor top coupling distributed Bragg reflector mirror is replaced by an undoped gallium-arsenide MHCG. We show how the optical field intensity distribution of the VCSEL's fundamental mode is controlled by the combination of the number of residual distributed Bragg reflector (DBR) mirror periods and the physical design of the topmost gallium-arsenide MHCG. Additionally, we numerically investigate the confinement factors of our VCSELs and show that this parameter for the MHCG DBR VCSELs may only be properly determined in two or three dimensions due to the periodic nature of the grating mirror.

Index-antiguided planar waveguide lasers with large mode area

NASA Astrophysics Data System (ADS)

Liu, Yuanye

The on-going research and application interests with high power large-mode-area (LMA) waveguide lasers, especially in fiber geometry, at the beginning of this century drive the development of many novel waveguide designs. Index antiguiding, proposed by Siegman in 2003, is among one of them. The goal for index antiguiding is to introduce transversal modal loss with the relative simple waveguide design while maintain single transverse mode operation for good beam quality. The idea which is selectively support of fundamental mode is facilitated by involving certain level of signal regeneration inside the waveguide core. Since the modal loss is closed associated with waveguide design parameters such as core size and refractive index, the amount of gain inside the core provides active control of transverse modes inside index-antiguiding waveguide. For example, fundamental transverse mode inside such waveguide can be excited and propagate lossless when sufficient optical gain is provided. This often requires doped waveguide core and optical pumping at corresponding absorption band. However, the involvement of optical pumping also has its consequences. Phenomena such as thermal-optic effect and gain spatial hole-burning which are commonly found in bulk lasers request attention when scaling up output power with LMA index-antiguided waveguide amplifiers and resonators. In response, three key challenges of index-antiguided planar waveguide lasers, namely, guiding mechanism, power efficiency and transverse mode discrimination, are analyzed theoretically and experimentally in this dissertation. Experiments are based on two index-antiguided planar waveguide chips, whose core thickness are 220 microm and 400 microm respectively. The material of waveguide core is 1% Neodymium-doped Yttrium Aluminium garnet, or Nd:YAG while the cladding is made from Terbium Gallium garnet, or TGG. Due to the face pumping and limited pump power, it is found, with 220 microm-thick-core chip, that the guidance of the fundamental transverse mode along two orthogonal directions in a transverse plane is different. Along the bounded direction, index antiguiding prevails with negligible thermal refractive focusing while along the unbounded direction, the lasing mode is guided by thermal refractive focusing with negligible quadratic gain focusing. It is also founded that the quadratic thermal focusing will dominate the mode guidance in 220 microm chip with the help of additional pump. All these discovery calls for an active thermal control. The modal discriminative loss, though beneficial for transverse mode control, yet reduces the lasing efficiency. To model it, a 3-D lasing output power calculation model is developed based on spatial rate equations. The simulation results show good agreement with experiment data where slope efficiency curve are measured using multiple output couplers. The 10% slope efficiency with respect to incident pump power is the highest slope efficiency recorded in index-antiguided waveguide continuous-wave lasers. The model indicates more efficient pump absorption can facilitate further power scaling. The role of the modal discriminative loss in transverse mode competition is discussed. A theoretical model based on Rigrod analysis and spatial hole-burning is developed. The simulation shows reasonable agreement with experiment results in both chips. The single fundamental mode operation up to 10 times above the lasing threshold for 220 microm chip is achieved, which is limited by the incident pump power. However, as the core size increases, the modal distributed loss due to the index antiguiding is found to be less effective in transverse mode control. Other modal loss is needed to facilitate the suppression of higher-order modes. Based on the model, a strategy is proposed aiming to maximize the single mode output. It is also noted that the transverse mode competition model is also suitable for other lasers system with well-defined modal loss. Based on the models and experiment data, the index-antiguided planar waveguide lasers are proved to be capable of maintaining large-mode-area single transverse mode operation with the potential of power scaling. However, it is also shown that proper waveguide design is essential. The remaining challenges are the material choices for waveguide fabrication, especially for high power applications.

AQUAdexIM: highly efficient in-memory indexing and querying of astronomy time series images

NASA Astrophysics Data System (ADS)

Hong, Zhi; Yu, Ce; Wang, Jie; Xiao, Jian; Cui, Chenzhou; Sun, Jizhou

2016-12-01

Astronomy has always been, and will continue to be, a data-based science, and astronomers nowadays are faced with increasingly massive datasets, one key problem of which is to efficiently retrieve the desired cup of data from the ocean. AQUAdexIM, an innovative spatial indexing and querying method, performs highly efficient on-the-fly queries under users' request to search for Time Series Images from existing observation data on the server side and only return the desired FITS images to users, so users no longer need to download entire datasets to their local machines, which will only become more and more impractical as the data size keeps increasing. Moreover, AQUAdexIM manages to keep a very low storage space overhead and its specially designed in-memory index structure enables it to search for Time Series Images of a given area of the sky 10 times faster than using Redis, a state-of-the-art in-memory database.

An analytical probabilistic model of the quality efficiency of a sewer tank

NASA Astrophysics Data System (ADS)

Balistrocchi, Matteo; Grossi, Giovanna; Bacchi, Baldassare

2009-12-01

The assessment of the efficiency of a storm water storage facility devoted to the sewer overflow control in urban areas strictly depends on the ability to model the main features of the rainfall-runoff routing process and the related wet weather pollution delivery. In this paper the possibility of applying the analytical probabilistic approach for developing a tank design method, whose potentials are similar to the continuous simulations, is proved. In the model derivation the quality issues of such devices were implemented. The formulation is based on a Weibull probabilistic model of the main characteristics of the rainfall process and on a power law describing the relationship between the dimensionless storm water cumulative runoff volume and the dimensionless cumulative pollutograph. Following this approach, efficiency indexes were established. The proposed model was verified by comparing its results to those obtained by continuous simulations; satisfactory agreement is shown for the proposed efficiency indexes.

Development of modelling algorithm of technological systems by statistical tests

NASA Astrophysics Data System (ADS)

Shemshura, E. A.; Otrokov, A. V.; Chernyh, V. G.

2018-03-01

The paper tackles the problem of economic assessment of design efficiency regarding various technological systems at the stage of their operation. The modelling algorithm of a technological system was performed using statistical tests and with account of the reliability index allows estimating the level of machinery technical excellence and defining the efficiency of design reliability against its performance. Economic feasibility of its application shall be determined on the basis of service quality of a technological system with further forecasting of volumes and the range of spare parts supply.

GRIN planar waveguide concentrator used with a single axis tracker.

PubMed

Bouchard, Sébastien; Thibault, Simon

2014-03-10

It is generally accepted that small to medium level concentrators could be used as cost-competitive replacements for tracked solar panels. The objective is to design a system that can reach a good level of sun concentration with only one sun-tracking axis and is cheap to fabricate. As the most critical parameter for all concentrator designs, optical efficiency needed improvement to reduce the cost of power produced by our system. By using a graded-index planar waveguide with an index profile similar to SELFOC fiber, the ray's path can be controlled. Also, the concentrator can be fabricated in a single block, which reduces Fresnel reflections. Overall, the optical efficiency can be improved by as much as 33% compared to the same system made with a homogeneous waveguide. Furthermore, the ability to cost-effectively fabricate the concentrator by molding can be preserved, making it possible to reduce the cost of the solar power produced.

GRIN planar waveguide concentrator used with a single axis tracker.

PubMed

Bouchard, Sébastien; Thibault, Simon

2014-03-10

It is generally accepted that small to medium level concentrators could be used as cost-competitive replacements for tracked solar panels. The objective is to design a system that can reach a good level of sun concentration with only one sun-tracking axis and is cheap to fabricate. As the most critical parameter for all concentrator designs, optical efficiency needed improvement to reduce the cost of power produced by our system. By using a graded-index planar waveguide with an index profile similar to SELFOC fiber, the ray’s path can be controlled. Also, the concentrator can be fabricated in a single block, which reduces Fresnel reflections. Overall, the optical efficiency can be improved by as much as 33% compared to the same system made with a homogeneous waveguide. Furthermore, the ability to cost-effectively fabricate the concentrator by molding can be preserved, making it possible to reduce the cost of the solar power produced.

Design of cladding rods-assisted depressed-core few-mode fibers with improved modal spacing

NASA Astrophysics Data System (ADS)

Han, Jiawei; Zhang, Jie

2018-03-01

This paper investigates the design details of cladding rods-assisted (CRA) depressed-core (DC) few-mode fibers (FMFs) that feature more equally spaced linearly polarized (LP) modal effective indices, suitable for high-spatial-density weakly-coupled mode-division multiplexing systems. The influences of the index profile of cladding rods on LP mode-resolved effective index, bending sensitivity, and effective area Aeff, are numerically described. Based on the design considerations of LP modal Aeff-dependent spatial efficiency and LP modal bending loss-dependent robustness, the small LP21-LP02 and LP22-LP03 modal spacing limitations, encountered in state-of-the-art weakly-coupled step-index FMFs, have been substantially improved by at least 25%. In addition, the proposed CRA DC FMFs also show sufficiently large effective areas (in excess of 110 μm2) for all guided LP modes, which are expected to exhibit good nonlinear performance.

Nodal failure index approach to groundwater remediation design

USGS Publications Warehouse

Lee, J.; Reeves, H.W.; Dowding, C.H.

2008-01-01

Computer simulations often are used to design and to optimize groundwater remediation systems. We present a new computationally efficient approach that calculates the reliability of remedial design at every location in a model domain with a single simulation. The estimated reliability and other model information are used to select a best remedial option for given site conditions, conceptual model, and available data. To evaluate design performance, we introduce the nodal failure index (NFI) to determine the number of nodal locations at which the probability of success is below the design requirement. The strength of the NFI approach is that selected areas of interest can be specified for analysis and the best remedial design determined for this target region. An example application of the NFI approach using a hypothetical model shows how the spatial distribution of reliability can be used for a decision support system in groundwater remediation design. ?? 2008 ASCE.

Prospects and limitations of full-text index structures in genome analysis

PubMed Central

Vyverman, Michaël; De Baets, Bernard; Fack, Veerle; Dawyndt, Peter

2012-01-01

The combination of incessant advances in sequencing technology producing large amounts of data and innovative bioinformatics approaches, designed to cope with this data flood, has led to new interesting results in the life sciences. Given the magnitude of sequence data to be processed, many bioinformatics tools rely on efficient solutions to a variety of complex string problems. These solutions include fast heuristic algorithms and advanced data structures, generally referred to as index structures. Although the importance of index structures is generally known to the bioinformatics community, the design and potency of these data structures, as well as their properties and limitations, are less understood. Moreover, the last decade has seen a boom in the number of variant index structures featuring complex and diverse memory-time trade-offs. This article brings a comprehensive state-of-the-art overview of the most popular index structures and their recently developed variants. Their features, interrelationships, the trade-offs they impose, but also their practical limitations, are explained and compared. PMID:22584621

Nonimaging optical concentrators using graded-index dielectric.

PubMed

Zitelli, M

2014-04-01

A new generation of inhomogeneous nonimaging optical concentrators is proposed, able to achieve simultaneously high optical efficiency and acceptance solid angle at a given geometrical concentration factor. General design methods are given, and concentrators are numerically investigated and optimized.

Automatic design of basin-specific drought indexes for highly regulated water systems

NASA Astrophysics Data System (ADS)

Zaniolo, Marta; Giuliani, Matteo; Castelletti, Andrea Francesco; Pulido-Velazquez, Manuel

2018-04-01

Socio-economic costs of drought are progressively increasing worldwide due to undergoing alterations of hydro-meteorological regimes induced by climate change. Although drought management is largely studied in the literature, traditional drought indexes often fail at detecting critical events in highly regulated systems, where natural water availability is conditioned by the operation of water infrastructures such as dams, diversions, and pumping wells. Here, ad hoc index formulations are usually adopted based on empirical combinations of several, supposed-to-be significant, hydro-meteorological variables. These customized formulations, however, while effective in the design basin, can hardly be generalized and transferred to different contexts. In this study, we contribute FRIDA (FRamework for Index-based Drought Analysis), a novel framework for the automatic design of basin-customized drought indexes. In contrast to ad hoc empirical approaches, FRIDA is fully automated, generalizable, and portable across different basins. FRIDA builds an index representing a surrogate of the drought conditions of the basin, computed by combining all the relevant available information about the water circulating in the system identified by means of a feature extraction algorithm. We used the Wrapper for Quasi-Equally Informative Subset Selection (W-QEISS), which features a multi-objective evolutionary algorithm to find Pareto-efficient subsets of variables by maximizing the wrapper accuracy, minimizing the number of selected variables, and optimizing relevance and redundancy of the subset. The preferred variable subset is selected among the efficient solutions and used to formulate the final index according to alternative model structures. We apply FRIDA to the case study of the Jucar river basin (Spain), a drought-prone and highly regulated Mediterranean water resource system, where an advanced drought management plan relying on the formulation of an ad hoc state index is used for triggering drought management measures. The state index was constructed empirically with a trial-and-error process begun in the 1980s and finalized in 2007, guided by the experts from the Confederación Hidrográfica del Júcar (CHJ). Our results show that the automated variable selection outcomes align with CHJ's 25-year-long empirical refinement. In addition, the resultant FRIDA index outperforms the official State Index in terms of accuracy in reproducing the target variable and cardinality of the selected inputs set.

Low cost and high performance GPON, GEPON and RFoG optical network pentaplexer module design using diffractive grating approach

NASA Astrophysics Data System (ADS)

Chen, I.-Ju; Chi, Chang-Chia; Tarn, Chen-Wen

2016-01-01

A new architecture of a pentaplexer transceiver module which can be used in GPON/GEPON and RFoG triple play optical networks with supporting of the multiple optical wavelengths of 1310 nm, 1490 nm, 1550 nm, 1610 nm, and 1650 nm, is proposed. By using diffractive grating elements combing with market readily available GRIN (Gradient-Index) lens, grating, mirrors, beamsplitter, LDs (Laser Diodes), and PDs (Photodetectors), the proposed design have the advantages of low cost, high efficiency/performance, easy design and manufacturing, over the contemporary triplex transceivers which are made of multilayer filters or waveguides that increase the complexity of manufacturing and reduce the performance efficiency. With the proposed design, a pentaplexer system can accommodate GPON/GEPON, RFoG, and monitoring integration services, total five optical wavelength channels into a hybrid-integrated TO-CAN package platform with sufficient efficiency.

Optical Fiber Design And Fabrication: Discussion On Recent Developments

NASA Astrophysics Data System (ADS)

Roy, Philippe; Devautour, Mathieu; Lavoute, Laure; Gaponov, Dmitry; Brasse, Gurvan; Hautreux, Stéphanie; Février, Sébastien; Restoin, Christine; Auguste, Jean-Louis; Gérôme, Frédéric; Humbert, Georges; Blondy, Jean-Marc

2008-10-01

Level of emitted power and beam quality of singlemode fiber lasers have been drastically increased at the expense of loss due to bend sensitivity, simplicity of manufacturing and packaging. Furthermore, the extension of the spectral coverage was primarily explored by exploiting non-linear effects, neglecting numerous possible transitions of rare earths. Through different research areas, we demonstrate the possibilities offered by new fiber designs and alternative methods of manufacturing. Photonic Band Gap fibers reconcile diffraction limited beam and large mode area with low bending loss. 80% slope efficiency is demonstrated together with a robust propagation allowing the fiber to be tightly bent until wounding radii as small as 6 cm. Highly ytterbium doped multimode core surrounded by high refractive index rods fiber exhibits a transverse singlemode behavior under continuous wave laser regime. A robust LP01 mode is observed and filtering effect is clearly observed. A non CVD process based on silica sand vitrification allows the synthesis of large and highly doped core with high index homogeneity, opening the way to design of efficient large mode area fiber lasers. 74% slope efficiency is measured, demonstrating the good quality of the core material. Finally, the use of rare earth (Er3+) doped zirconia nanocrystals in silica matrix offers a large panel of ignored energy transitions for visible or off-usual band of emission.

High-efficiency water-loaded microwave antenna in ultra-high-frequency band

NASA Astrophysics Data System (ADS)

Gong, Zilun; Bartone, Chris; Yang, Fuyi; Yao, Jie

2018-03-01

High-index dielectrics are widely used in microwave antennas to control the radiation characteristics. Liquid water, with a high dielectric index at microwave frequency, is an interesting material to achieving tunable functionalities. Here, we demonstrate a water-loaded microwave antenna system that has high loss-tolerance and wideband tunability enabled by fluidity. Our simulation and experimental results show that the resonance frequency can be effectively tuned by the size of loading water. Furthermore, the antenna systems with water loading can achieve high radiation efficiency (>90%) in the ultra-high-frequency (0.3-3 GHz) band. This work brings about opportunities in realistic tunable microwave antenna designs enabled by liquid.

Bilayer free-standing beam splitter for Fourier transform infrared spectrometry.

PubMed

Rowell, N L; Wang, E A

1996-06-01

We describe the design, fabrication, testing, and performance of a two-layer free-standing beam splitter for use in far-infrared Fourier transform infrared spectrometers. This bilayer beam splitter, consisting of a low-index polymer layer in combination with a high-index semiconductor layer, has an efficiency that is higher than that of the best combination of four single-layer Mylar beam splitters currently in use for spectrometry from 50 to 550 cm(-1).

New strategy to promote conversion efficiency using high-index nanostructures in thin-film solar cells

PubMed Central

Wang, DongLin; Su, Gang

2014-01-01

Nano-scaled metallic or dielectric structures may provide various ways to trap light into thin-film solar cells for improving the conversion efficiency. In most schemes, the textured active layers are involved into light trapping structures that can provide perfect optical benefits but also bring undesirable degradation of electrical performance. Here we propose a novel approach to design high-performance thin-film solar cells. In our strategy, a flat active layer is adopted for avoiding electrical degradation, and an optimization algorithm is applied to seek for an optimized light trapping structure for the best optical benefit. As an example, we show that the efficiency of a flat a-Si:H thin-film solar cell can be promoted close to the certified highest value. It is also pointed out that, by choosing appropriate dielectric materials with high refractive index (>3) and high transmissivity in wavelength region of 350 nm–800 nm, the conversion efficiency of solar cells can be further enhanced. PMID:25418477

Construction of social value or utility-based health indices: the usefulness of factorial experimental design plans.

PubMed

Cadman, D; Goldsmith, C

1986-01-01

Global indices, which aggregate multiple health or function attributes into a single summary indicator, are useful measures in health research. Two key issues must be addressed in the initial stages of index construction from the universe of possible health and function attributes, which ones should be included in a new index? and how simple can the statistical model be to combine attributes into a single numeric index value? Factorial experimental designs were used in the initial stages of developing a function index for evaluating a program for the care of young handicapped children. Beginning with eight attributes judged important to the goals of the program by clinicians, social preference values for different function states were obtained from 32 parents of handicapped children and 32 members of the community. Using category rating methods each rater scored 16 written multi-attribute case descriptions which contained information about a child's status for all eight attributes. Either a good or poor level of each function attribute and age 3 or 5 years were described in each case. Thus, 2(8) = 256 different cases were rated. Two factorial design plans were selected and used to allocate case descriptions to raters. Analysis of variance determined that seven of the eight clinician selected attributes were required in a social value based index for handicapped children. Most importantly, the subsequent steps of index construction could be greatly simplified by the finding that a simple additive statistical model without complex attribute interaction terms was adequate for the index. We conclude that factorial experimental designs are an efficient, feasible and powerful tool for the initial stages of constructing a multi-attribute health index.

Design of LED projector based on gradient-index lens

NASA Astrophysics Data System (ADS)

Qian, Liyong; Zhu, Xiangbing; Cui, Haitian; Wang, Yuanhang

2018-01-01

In this study, a new type of projector light path is designed to eliminate the deficits of existing projection systems, such as complex structure and low collection efficiency. Using a three-color LED array as the lighting source, by means of the special optical properties of a gradient-index lens, the complex structure of the traditional projector is simplified. Traditional components, such as the color wheel, relay lens, and mirror, become unnecessary. In this way, traditional problems, such as low utilization of light energy and loss of light energy, are solved. With the help of Zemax software, the projection lens is optimized. The optimized projection lens, LED, gradient-index lens, and digital micromirror device are imported into Tracepro. The ray tracing results show that both the utilization of light energy and the uniformity are improved significantly.

Optimization of single photon detection model based on GM-APD

NASA Astrophysics Data System (ADS)

Chen, Yu; Yang, Yi; Hao, Peiyu

2017-11-01

One hundred kilometers high precision laser ranging hopes the detector has very strong detection ability for very weak light. At present, Geiger-Mode of Avalanche Photodiode has more use. It has high sensitivity and high photoelectric conversion efficiency. Selecting and designing the detector parameters according to the system index is of great importance to the improvement of photon detection efficiency. Design optimization requires a good model. In this paper, we research the existing Poisson distribution model, and consider the important detector parameters of dark count rate, dead time, quantum efficiency and so on. We improve the optimization of detection model, select the appropriate parameters to achieve optimal photon detection efficiency. The simulation is carried out by using Matlab and compared with the actual test results. The rationality of the model is verified. It has certain reference value in engineering applications.

Trade-offs between effectiveness and efficiency in stroke rehabilitation.

PubMed

Koh, Gerald Choon-Huat; Chen, Cynthia; Cheong, Angela; Choo, Tai Bee; Pui, Choi Kwok; Phoon, Fong Ngan; Ming, Chan Kin; Yeow, Tan Boon; Petrella, Robert; Thind, Amardeep; Koh, David; Seng, Chia Kee

2012-12-01

Most stroke research has studied rehabilitation effectiveness and rehabilitation efficiency separately and not investigated the potential trade-offs between these two indices of rehabilitation. To determine whether there is a trade-off between independent factors of rehabilitation effectiveness and rehabilitation efficiency. Using a retrospective cohort study design, we studied all stroke patients (n = 2810) from two sub-acute rehabilitation hospitals from 1996 to 2005, representing 87·5% of national bed-years during the same period. Independent predictors of poorer rehabilitation effectiveness and log rehabilitation efficiency were • older age • race-ethnicity • caregiver availability • ischemic stroke • longer time to admission • dementia • admission Barthel Index score, and • length of stay. Rehabilitation effectiveness was lower in females, and the gender differences were significantly lower in those aged ≤70 years (β -4·7 (95% confidence interval -7·4 to -2·0)). There were trade-offs between effectiveness and efficiency with respect to admission Barthel Index score and length of stay. An increase of 10 in admission Barthel Index score predicted an increase of 3·6% (95% confidence interval 3·2-4·0) in effectiveness but a decrease of 0·04 (95% confidence interval -0·05 to -0·02) in log efficiency (a reduction of efficiency by 1·0 per 30 days). An increase in log length of stay by 1 (length of stay of 2·7 days) predicted an increase of 8·0% (95% confidence interval 5·7-10·3) in effectiveness but a decrease of 0·82 (95% confidence interval -0·90 to -0·74) in log efficiency (equivalent to a reduction in efficiency by 2·3 per 30 days). For optimal rehabilitation effectiveness and rehabilitation efficiency, the admission Barthel Index score was 30-62 and length of stay was 37-41 days. There are trade-offs between effectiveness and efficiency during inpatient sub-acute stroke rehabilitation with respect to admission functional status and length of stay. © 2011 The Authors. International Journal of Stroke © 2011 World Stroke Organization.

[sgRNA design for the CRISPR/Cas9 system and evaluation of its off-target effects].

PubMed

Xie, Sheng-song; Zhang, Yi; Zhang, Li-sheng; Li, Guang-lei; Zhao, Chang-zhi; Ni, Pan; Zhao, Shu-hong

2015-11-01

The third generation of CRISPR/Cas9-mediated genome editing technology has been successfully applied to genome modification of various species including animals, plants and microorganisms. How to improve the efficiency of CRISPR/Cas9 genome editing and reduce its off-target effects has been extensively explored in this field. Using sgRNA (Small guide RNA) with high efficiency and specificity is one of the critical factors for successful genome editing. Several software have been developed for sgRNA design and/or off-target evaluation, which have advantages and disadvantages respectively. In this review, we summarize characters of 16 kinds online and standalone software for sgRNA design and/or off-target evaluation and conduct a comparative analysis of these different kinds of software through developing 38 evaluation indexes. We also summarize 11 experimental approaches for testing genome editing efficiency and off-target effects as well as how to screen highly efficient and specific sgRNA.

Vector-borne disease risk indexes in spatially structured populations

PubMed Central

Anzo-Hernández, Andrés; Bonilla-Capilla, Beatriz; Soto-Bajo, Moisés; Fraguela-Collar, Andrés

2018-01-01

There are economic and physical limitations when applying prevention and control strategies for urban vector borne diseases. Consequently, there are increasing concerns and interest in designing efficient strategies and regulations that health agencies can follow in order to reduce the imminent impact of viruses like Dengue, Zika and Chikungunya. That includes fumigation, abatization, reducing the hatcheries, picking up trash, information campaigns. A basic question that arise when designing control strategies is about which and where these ones should focus. In other words, one would like to know whether preventing the contagion or decrease vector population, and in which area of the city, is more efficient. In this work, we propose risk indexes based on the idea of secondary cases from patch to patch. Thus, they take into account human mobility and indicate which patch has more chance to be a corridor for the spread of the disease and which is more vulnerable, i.e. more likely to have cases?. They can also indicate the neighborhood where hatchery control will reduce more the number of potential cases. In order to illustrate the usefulness of these indexes, we run a set of numerical simulations in a mathematical model that takes into account the urban mobility and the differences in population density among the areas of a city. If we label by i a particular neighborhood, the transmission risk index (TRi) measures the potential secondary cases caused by a host in that neighborhood. The vector transmission risk index (VTRi) measures the potential secondary cases caused by a vector. Finally, the vulnerability risk index (VRi) measures the potential secondary cases in the neighborhood. Transmission indexes can be used to give geographical priority to some neighborhoods when applying prevention and control measures. On the other hand, the vulnerability index can be useful to implement monitoring campaigns or public health investment. PMID:29432455

Methods for assessing the energy-saving efficiency of industrial symbiosis in industrial parks.

PubMed

Li, Wenfeng; Cui, Zhaojie; Han, Feng

2015-01-01

The available energy resources are being depleted worldwide. Industrial symbiosis (IS) provides a promising approach for increasing the efficiency of energy utilization, with numerous studies reporting the superiority of this technology. However, studies quantifying the energy-saving efficiency of IS remain insufficient. This paper proposes an index system for the quantitative evaluation of the energy-saving efficiency of IS. Both energy-saving and financial indexes were selected, the former include the IS energy-saving index, the contribution rate of energy saved through IS, fractional energy savings, and cut rate of energy consumption per total output value; and the latter include the IS investment payback period, IS input-output ratio, net present value (NPV), and internal rate of return (IRR) of IS. The proposed methods were applied to a case study on the XF Industrial Park (XF IP), in the city of Liaocheng in Shandong Province of China. Three energy-saving channels using IS were found in the XF IP: (a) utilizing the energy of high-temperature materials among industrial processes, (b) recovering waste heat and steam between different processes, and (c) saving energy by sharing infrastructures. The results showed that the energy efficiency index of IS was 0.326, accounting for 34.6% of the comprehensive energy-saving index in 2011, and the fractional energy-savings were 12.42%. The index of energy consumption per total industrial output value varied from 90.9 tce/MRMB to 51.6 tce/MRMB. Thus, the cut rate of energy consumption per total industrial output value was 43.42%. The average values of the IS input-output ratio was 406.2 RMB/tce, 57.2% lower than the price of standard coal. Static investment payback period in the XF IP was 8.5 months, indicating that the XF IP began to earn profit 8.5 months after the construction of all IS modes. The NVP and IRR of each IS mode in the XF IP were greater than zero, with average values equal to 1,789.96 MRMB and 140.96%, respectively. The computation result for each indicator revealed that IS could lead to the use of energy with high efficiency and lighten the financial burden of enterprises in the XF IP. And the proposed index system may help IPs and EIPs to make strategic decisions when designing IS modes.

Repeated significance tests of linear combinations of sensitivity and specificity of a diagnostic biomarker

PubMed Central

Wu, Mixia; Shu, Yu; Li, Zhaohai; Liu, Aiyi

2016-01-01

A sequential design is proposed to test whether the accuracy of a binary diagnostic biomarker meets the minimal level of acceptance. The accuracy of a binary diagnostic biomarker is a linear combination of the marker’s sensitivity and specificity. The objective of the sequential method is to minimize the maximum expected sample size under the null hypothesis that the marker’s accuracy is below the minimal level of acceptance. The exact results of two-stage designs based on Youden’s index and efficiency indicate that the maximum expected sample sizes are smaller than the sample sizes of the fixed designs. Exact methods are also developed for estimation, confidence interval and p-value concerning the proposed accuracy index upon termination of the sequential testing. PMID:26947768

k-neighborhood Decentralization: A Comprehensive Solution to Index the UMLS for Large Scale Knowledge Discovery

PubMed Central

Xiang, Yang; Lu, Kewei; James, Stephen L.; Borlawsky, Tara B.; Huang, Kun; Payne, Philip R.O.

2011-01-01

The Unified Medical Language System (UMLS) is the largest thesaurus in the biomedical informatics domain. Previous works have shown that knowledge constructs comprised of transitively-associated UMLS concepts are effective for discovering potentially novel biomedical hypotheses. However, the extremely large size of the UMLS becomes a major challenge for these applications. To address this problem, we designed a k-neighborhood Decentralization Labeling Scheme (kDLS) for the UMLS, and the corresponding method to effectively evaluate the kDLS indexing results. kDLS provides a comprehensive solution for indexing the UMLS for very efficient large scale knowledge discovery. We demonstrated that it is highly effective to use kDLS paths to prioritize disease-gene relations across the whole genome, with extremely high fold-enrichment values. To our knowledge, this is the first indexing scheme capable of supporting efficient large scale knowledge discovery on the UMLS as a whole. Our expectation is that kDLS will become a vital engine for retrieving information and generating hypotheses from the UMLS for future medical informatics applications. PMID:22154838

k-Neighborhood decentralization: a comprehensive solution to index the UMLS for large scale knowledge discovery.

PubMed

Xiang, Yang; Lu, Kewei; James, Stephen L; Borlawsky, Tara B; Huang, Kun; Payne, Philip R O

2012-04-01

The Unified Medical Language System (UMLS) is the largest thesaurus in the biomedical informatics domain. Previous works have shown that knowledge constructs comprised of transitively-associated UMLS concepts are effective for discovering potentially novel biomedical hypotheses. However, the extremely large size of the UMLS becomes a major challenge for these applications. To address this problem, we designed a k-neighborhood Decentralization Labeling Scheme (kDLS) for the UMLS, and the corresponding method to effectively evaluate the kDLS indexing results. kDLS provides a comprehensive solution for indexing the UMLS for very efficient large scale knowledge discovery. We demonstrated that it is highly effective to use kDLS paths to prioritize disease-gene relations across the whole genome, with extremely high fold-enrichment values. To our knowledge, this is the first indexing scheme capable of supporting efficient large scale knowledge discovery on the UMLS as a whole. Our expectation is that kDLS will become a vital engine for retrieving information and generating hypotheses from the UMLS for future medical informatics applications. Copyright © 2011 Elsevier Inc. All rights reserved.

Reliability Analysis and Reliability-Based Design Optimization of Circular Composite Cylinders Under Axial Compression

NASA Technical Reports Server (NTRS)

Rais-Rohani, Masoud

2001-01-01

This report describes the preliminary results of an investigation on component reliability analysis and reliability-based design optimization of thin-walled circular composite cylinders with average diameter and average length of 15 inches. Structural reliability is based on axial buckling strength of the cylinder. Both Monte Carlo simulation and First Order Reliability Method are considered for reliability analysis with the latter incorporated into the reliability-based structural optimization problem. To improve the efficiency of reliability sensitivity analysis and design optimization solution, the buckling strength of the cylinder is estimated using a second-order response surface model. The sensitivity of the reliability index with respect to the mean and standard deviation of each random variable is calculated and compared. The reliability index is found to be extremely sensitive to the applied load and elastic modulus of the material in the fiber direction. The cylinder diameter was found to have the third highest impact on the reliability index. Also the uncertainty in the applied load, captured by examining different values for its coefficient of variation, is found to have a large influence on cylinder reliability. The optimization problem for minimum weight is solved subject to a design constraint on element reliability index. The methodology, solution procedure and optimization results are included in this report.

Rugate filter for light-trapping in solar cells.

PubMed

Fahr, Stephan; Ulbrich, Carolin; Kirchartz, Thomas; Rau, Uwe; Rockstuhl, Carsten; Lederer, Falk

2008-06-23

We suggest a design for a coating that could be applied on top of any solar cell having at least one diffusing surface. This coating acts as an angle and wavelength selective filter, which increases the average path length and absorptance at long wavelengths without altering the solar cell performance at short wavelengths. The filter design is based on a continuous variation of the refractive index in order to minimize undesired reflection losses. Numerical procedures are used to optimize the filter for a 10 microm thick monocrystalline silicon solar cell, which lifts the efficiency above the Auger limit for unconcentrated illumination. The feasibility to fabricate such filters is also discussed, considering a finite available refractive index range.

SymDex: increasing the efficiency of chemical fingerprint similarity searches for comparing large chemical libraries by using query set indexing.

PubMed

Tai, David; Fang, Jianwen

2012-08-27

The large sizes of today's chemical databases require efficient algorithms to perform similarity searches. It can be very time consuming to compare two large chemical databases. This paper seeks to build upon existing research efforts by describing a novel strategy for accelerating existing search algorithms for comparing large chemical collections. The quest for efficiency has focused on developing better indexing algorithms by creating heuristics for searching individual chemical against a chemical library by detecting and eliminating needless similarity calculations. For comparing two chemical collections, these algorithms simply execute searches for each chemical in the query set sequentially. The strategy presented in this paper achieves a speedup upon these algorithms by indexing the set of all query chemicals so redundant calculations that arise in the case of sequential searches are eliminated. We implement this novel algorithm by developing a similarity search program called Symmetric inDexing or SymDex. SymDex shows over a 232% maximum speedup compared to the state-of-the-art single query search algorithm over real data for various fingerprint lengths. Considerable speedup is even seen for batch searches where query set sizes are relatively small compared to typical database sizes. To the best of our knowledge, SymDex is the first search algorithm designed specifically for comparing chemical libraries. It can be adapted to most, if not all, existing indexing algorithms and shows potential for accelerating future similarity search algorithms for comparing chemical databases.

Design and analysis of a silicon-based antiresonant reflecting optical waveguide chemical sensor

NASA Astrophysics Data System (ADS)

Remley, Kate A.; Weisshaar, Andreas

1996-08-01

The design of a silicon-based antiresonant reflecting optical waveguide (ARROW) chemical sensor is presented, and its theoretical performance is compared with that of a conventional structure. The use of an ARROW structure permits incorporation of a thick guiding region for efficient coupling to a single-mode fiber. A high-index overlay is added to fine tune the sensitivity of the ARROW chemical sensor. The sensitivity of the sensor is presented, and design trade-offs are discussed.

How to obtain a shortest mode converter based on periodic waveguide with limited index contrast?

NASA Astrophysics Data System (ADS)

Zhang, Lingxuan; Zhang, Wenfu; Wang, Guoxi; Hu, Yaowei; Ge, Zhiqiang; Wang, Leiran; Sun, Qibing; Wang, Weiqiang; Gong, Yongkang; Zhao, Wei

2017-05-01

Mode converter is one of most significant elements in photonic integrated circuits. It relies on increasing index contrast to shorten its length. However, index contrast is limited for technology. In addition, an overlarge index contrast leads to some disadvantages, such as large scattering loss, reflection loss, and small tolerance for manufacturing. Thus, an approximate scheme to design a mode converter is manipulating the transverse distribution of index to achieve the minimum length when the index contrast is given. We have analytically deduced the theoretical maximum coupled efficiency in periodic waveguide, which determines the minimum coupling length of mode converter. What is more, we have demonstrated how to construct a distribution function of indices in a cross section of waveguide to achieve the minimum length and a case is also given to illustrate the process. Proofs, based on both mathematic derivation and numerical simulation, have been exhibited in the paper.

Theoretical parametric study of the relative advantages of winglets and wing-tip extensions

NASA Technical Reports Server (NTRS)

Heyson, H. H.; Riebe, G. D.; Fulton, C. L.

1977-01-01

It was found that for identical increases in bending moment, a winglet provides a greater gain in induced efficiency than a tip extension. Winglet toe-in angle allows design trades between efficiency and root moment. A winglet showed the greatest benefit when the wing loads were heavy near the tip. Washout diminished the benefit of either tip modification, and the gain in induced efficiency became a function of lift coefficient; heavy wing loadings obtained the greatest benefit from a winglet, and low speed performance was enhanced even more than cruise performance. Both induced efficiency and bending moment increased with winglet length and outward cant. The benefit of a winglet relative to a tip extension was greatest for a nearly vertical winglet. Root bending moment was proportional to the minimum weight of bending material required in the wing; it is a valid index of the impact of tip modifications on a new wing design.

Theoretical Parametric Study of the Relative Advantages of Winglets and Wing-Tip Extensions

NASA Technical Reports Server (NTRS)

Heyson, H. H.; Riebe, G. D.; Fulton, C. L.

1977-01-01

For identical increases in bending moment, a winglet provides a greater gain in induced efficiency than tip extension. Winglet toe angle allows design trades between efficiency and root moment. A winglet shows the greatest benefit when the wing loads are heavy near the tip. Washout diminishes the benefit of either tip modification, and the gain in induced efficiency becomes a function of lift coefficient; thus, heavy wing loadings obtain the greatest benefit from a winglet, and low-speed performance is enhanced even more than cruise performance. Both induced efficiency and bending moment increase with winglet length and outward cant. The benefit of a winglet relative to a tip extension is greatest for a nearly vertical winglet. Root bending moment is proportional to the minimum weight of bending material required in the wing; thus, it is a valid index of the impact of tip modifications on a new wing design.

Research on the content framework of information disclosure mechanism in Shanxi power market

NASA Astrophysics Data System (ADS)

Sun, Yanzhang; Li, Tao; Hou, Zhehui; Cao, Xiaozhong

2018-06-01

With the further development of the power reform, establishing a sound power system with rich content and efficient operation has become an urgent need. Faced with the current circumstance of power market information disclosure in Shanxi province, this paper fully incorporates the actual situation and introduces the index into the power market information disclosure mechanism, and sets up the general information disclosure framework in Shanxi province power market on the basis of which A direct information disclosure mechanism and an indirect information disclosure mechanism were designed. Then we formulate comprehensive power index system, generation index system, transmission and distribution index system, and power utilization index system. In conclusion, the outcomes above will enrich power information disclosure mechanism in Shanxi province and will provide a platform for various market members as a guidance on setting right business decisions.

Full-subcarriers Polar-OFDM for optical spectrum-efficient transmission exploiting Polarization Multiplexing

NASA Astrophysics Data System (ADS)

Guo, Lei; Liu, Yejun; Zhou, Yufang; Wei, Xuetao; Liu, Yuying

2018-07-01

The exponential growth of the demand for broadband services has imposed great challenges on the design of spectrum-efficient optical transmission system in Passive Optical Network (PON). Recently, an innovative Orthogonal Frequency Division Multiplexing (OFDM) scheme, called Polar-OFDM (P-OFDM), has emerged as a promising solution to boost the spectral efficiency of optical transmission in PON. However, the traditional P-OFDM does not yet perform best in spectral efficiency as it only uses half of the total subcarriers. In this paper, we verify a promising complementation between Polarization Multiplexing (POLMUX) and P-OFDM aiming at higher spectral efficiency. We then propose the full-subcarriers P-OFDM by loading data on the even-indexed subcarriers of X polarization and the odd-indexed subcarriers of Y polarization, respectively. Thus, all of the subcarriers will be utilized for effective data transmission, which can double the spectral efficiency. More importantly, because the subcarriers are interlaced on different polarizations, the cross-polarization interference can be significantly mitigated, which enables the independent channel estimation and equalization at the receiver to recover the data carried on each polarization. Our evaluation results demonstrate that the proposed system realizes the double spectral efficiency of the traditional P-OFDM with reasonable Bit Error Rate (BER) performance loss.

High-directionality fiber-chip grating coupler with interleaved trenches and subwavelength index-matching structure.

PubMed

Benedikovic, Daniel; Alonso-Ramos, Carlos; Cheben, Pavel; Schmid, Jens H; Wang, Shurui; Xu, Dan-Xia; Lapointe, Jean; Janz, Siegfried; Halir, Robert; Ortega-Moñux, Alejandro; Wangüemert-Pérez, J Gonzalo; Molina-Fernández, Iñigo; Fédéli, Jean-Marc; Vivien, Laurent; Dado, Milan

2015-09-15

We present the first experimental demonstration of a new fiber-chip grating coupler concept that exploits the blazing effect by interleaving the standard full (220 nm) and shallow etch (70 nm) trenches in a 220 nm thick silicon layer. The high directionality is obtained by controlling the separation between the deep and shallow trenches to achieve constructive interference in the upward direction and destructive interference toward the silicon substrate. Utilizing this concept, the grating directionality can be maximized independent of the bottom oxide thickness. The coupler also includes a subwavelength-engineered index-matching region, designed to reduce the reflectivity at the interface between the injection waveguide and the grating. We report a measured fiber-chip coupling efficiency of -1.3  dB, the highest coupling efficiency achieved to date for a surface grating coupler in a 220 nm silicon-on-insulator platform fabricated in a conventional dual-etch process without high-index overlays or bottom mirrors.

Two-axis tracking using translation stages for a lens-to-channel waveguide solar concentrator.

PubMed

Liu, Yuxiao; Huang, Ran; Madsen, Christi K

2014-10-20

A two-axis tracking scheme designed for <250x concentration realized by a single-axis mechanical tracker and a translation stage is discussed. The translation stage is used for adjusting positions for seasonal sun movement. It has two-dimensional x-y tracking instead of horizontal movement x-only. This tracking method is compatible with planar waveguide solar concentrators. A prototype system with 50x concentration shows >75% optical efficiency throughout the year in simulation and >65% efficiency experimentally. This efficiency can be further improved by the use of anti-reflection layers and a larger waveguide refractive index.

Design and fabrication of a miniature objective consisting of high refractive index zinc sulfide lenses for laser surgery

PubMed Central

Shadfan, Adam; Pawlowski, Michal; Wang, Ye; Subramanian, Kaushik; Gabay, Ilan; Ben-Yakar, Adela; Tkaczyk, Tomasz

2016-01-01

A miniature laser ablation probe relying on an optical fiber to deliver light requires a high coupling efficiency objective with sufficient magnification in order to provide adequate power and field for surgery. A diffraction-limited optical design is presented that utilizes high refractive index zinc sulfide to meet specifications while reducing the miniature objective down to two lenses. The design has a hypercentric conjugate plane on the fiber side and is telecentric on the tissue end. Two versions of the objective were built on a diamond lathe—a traditional cylindrical design and a custom-tapered mount. Both received an antireflective coating. The objectives performed as designed in terms of observable resolution and field of view as measured by imaging a 1951 USAF resolution target. The slanted edge technique was used to find Strehl ratios of 0.75 and 0.78, respectively, indicating nearly diffraction-limited performance. Finally, preliminary ablation experiments indicated threshold fluence of gold film was comparable to similar reported probes. PMID:28579656

Design and fabrication of a miniature objective consisting of high refractive index zinc sulfide lenses for laser surgery

NASA Astrophysics Data System (ADS)

Shadfan, Adam; Pawlowski, Michal; Wang, Ye; Subramanian, Kaushik; Gabay, Ilan; Ben-Yakar, Adela; Tkaczyk, Tomasz

2016-02-01

A miniature laser ablation probe relying on an optical fiber to deliver light requires a high coupling efficiency objective with sufficient magnification in order to provide adequate power and field for surgery. A diffraction-limited optical design is presented that utilizes high refractive index zinc sulfide to meet specifications while reducing the miniature objective down to two lenses. The design has a hypercentric conjugate plane on the fiber side and is telecentric on the tissue end. Two versions of the objective were built on a diamond lathe-a traditional cylindrical design and a custom-tapered mount. Both received an antireflective coating. The objectives performed as designed in terms of observable resolution and field of view as measured by imaging a 1951 USAF resolution target. The slanted edge technique was used to find Strehl ratios of 0.75 and 0.78, respectively, indicating nearly diffraction-limited performance. Finally, preliminary ablation experiments indicated threshold fluence of gold film was comparable to similar reported probes.

An improved hierarchical A * algorithm in the optimization of parking lots

NASA Astrophysics Data System (ADS)

Wang, Yong; Wu, Junjuan; Wang, Ying

2017-08-01

In the parking lot parking path optimization, the traditional evaluation index is the shortest distance as the best index and it does not consider the actual road conditions. Now, the introduction of a more practical evaluation index can not only simplify the hardware design of the boot system but also save the software overhead. Firstly, we establish the parking lot network graph RPCDV mathematical model and all nodes in the network is divided into two layers which were constructed using different evaluation function base on the improved hierarchical A * algorithm which improves the time optimal path search efficiency and search precision of the evaluation index. The final results show that for different sections of the program attribute parameter algorithm always faster the time to find the optimal path.

FastBit Reference Manual

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

Wu, Kesheng

2007-08-02

An index in a database system is a data structure that utilizes redundant information about the base data to speed up common searching and retrieval operations. Most commonly used indexes are variants of B-trees, such as B+-tree and B*-tree. FastBit implements a set of alternative indexes call compressed bitmap indexes. Compared with B-tree variants, these indexes provide very efficient searching and retrieval operations by sacrificing the efficiency of updating the indexes after the modification of an individual record. In addition to the well-known strengths of bitmap indexes, FastBit has a special strength stemming from the bitmap compression scheme used. Themore » compression method is called the Word-Aligned Hybrid (WAH) code. It reduces the bitmap indexes to reasonable sizes and at the same time allows very efficient bitwise logical operations directly on the compressed bitmaps. Compared with the well-known compression methods such as LZ77 and Byte-aligned Bitmap code (BBC), WAH sacrifices some space efficiency for a significant improvement in operational efficiency. Since the bitwise logical operations are the most important operations needed to answer queries, using WAH compression has been shown to answer queries significantly faster than using other compression schemes. Theoretical analyses showed that WAH compressed bitmap indexes are optimal for one-dimensional range queries. Only the most efficient indexing schemes such as B+-tree and B*-tree have this optimality property. However, bitmap indexes are superior because they can efficiently answer multi-dimensional range queries by combining the answers to one-dimensional queries.« less

Interferometric measurement of refractive index modification in a single mode microfiber

NASA Astrophysics Data System (ADS)

Ahmed, Farid; Ahsani, Vahid; Jun, Martin B. G.

2017-02-01

Efficient and cost effective measurement of the refractive index profile in an optical fiber is a significant technical job to design and manufacture in-fiber photonic devices and communication systems. For instance, to design fiber gratings, it is required to estimate the refractive index modulation to be inscribed by the fabrication apparatus such as ultraviolet or infrared lasers. Mach-Zehnder interferometer (MZI) based quantification of refractive index change written in single mode microfiber by femtosecond laser radiation is presented in this study. The MZI is constructed by splicing a microfiber (core diameter: 3.75 μm, cladding diameter: 40 μm) between standard single mode fibers. To measure the RI inscribed by infrared femtosecond laser, 200 μm length of the core within the MZI was scanned with laser radiation. As the higher index was written within 200 μm length of the core, the transmission spectrum of the interferometer displayed a corresponding red shift. The observed spectral shift was used to calculate the amount of refractive index change inscribed by the femtosecond irradiation. For the MZI length of 3.25 mm, and spectral shift of 0.8 nm, the calculated refractive index was found to be 0.00022. The reported results display excellent agreement between theory and experimental findings. Demonstrated method provides simple yet very effective on-site measurement of index change in optical fibers. Since the MZI can be constructed in diverse fiber types, this technique offers flexibility to quantify index change in various optical fibers.

Design of FastQuery: How to Generalize Indexing and Querying System for Scientific Data

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

Wu, Jerry; Wu, Kesheng

2011-04-18

Modern scientific datasets present numerous data management and analysis challenges. State-of-the-art index and query technologies such as FastBit are critical for facilitating interactive exploration of large datasets. These technologies rely on adding auxiliary information to existing datasets to accelerate query processing. To use these indices, we need to match the relational data model used by the indexing systems with the array data model used by most scientific data, and to provide an efficient input and output layer for reading and writing the indices. In this work, we present a flexible design that can be easily applied to most scientific datamore » formats. We demonstrate this flexibility by applying it to two of the most commonly used scientific data formats, HDF5 and NetCDF. We present two case studies using simulation data from the particle accelerator and climate simulation communities. To demonstrate the effectiveness of the new design, we also present a detailed performance study using both synthetic and real scientific workloads.« less

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

None

Achieving aggressive energy efficiency targets requires tight coordination and clear communication among owners, designers, builders, and subcontractors. For this townhome project, MassDevelopment, the quasi-governmental agency owner, selected Metric Development of Boston, teaming with Building America team Consortium for Advanced Residential Buildings (CARB) and Cambridge Seven Architects, to build very high performing market-rate homes. Fort Devens is part of a decommissioned army base in working-class Harvard, Massachusetts, approximately one hour northwest of Boston. The team proposed 12 net zero energy-ready townhomes that were also designed to achieve a Home Energy Rating System (HERS) Index Score of 41 before adding renewables. Themore » team carefully planned the site to maximize solar access, daylighting, and efficient building forms.« less

Methods and apparatus for vertical coupling from dielectric waveguides

DOEpatents

Yaacobi, Ami; Cordova, Brad Gilbert

2014-06-17

A frequency-chirped nano-antenna provides efficient sub-wavelength vertical emission from a dielectric waveguide. In one example, this nano-antenna includes a set of plasmonic dipoles on the opposite side of a SiYV.sub.4 waveguide from a ground plane. The resulting structure, which is less than half a wavelength long, emits a broadband beam (e.g., >300 nm) that can be coupled into an optical fiber. In some embodiments, a diffractive optical element with unevenly shaped regions of high- and low-index dielectric material collimates the broadband beam for higher coupling efficiency. In some cases, a negative lens element between the nano-antenna and the diffractive optical element accelerates the emitted beam's divergence (and improves coupling efficiency), allowing for more compact packaging. Like the diffractive optical element, the negative lens element includes unevenly shaped regions of high- and low-index dielectric material that can be designed to compensate for aberrations in the beam emitted by the nano-antenna.

Assessing the lipophilicity of fragments and early hits

NASA Astrophysics Data System (ADS)

Mortenson, Paul N.; Murray, Christopher W.

2011-07-01

A key challenge in many drug discovery programs is to accurately assess the potential value of screening hits. This is particularly true in fragment-based drug design (FBDD), where the hits often bind relatively weakly, but are correspondingly small. Ligand efficiency (LE) considers both the potency and the size of the molecule, and enables us to estimate whether or not an initial hit is likely to be optimisable to a potent, druglike lead. While size is a key property that needs to be controlled in a small molecule drug, there are a number of additional properties that should also be considered. Lipophilicity is amongst the most important of these additional properties, and here we present a new efficiency index (LLEAT) that combines lipophilicity, size and potency. The index is intuitively defined, and has been designed to have the same target value and dynamic range as LE, making it easily interpretable by medicinal chemists. Monitoring both LE and LLEAT should help both in the selection of more promising fragment hits, and controlling molecular weight and lipophilicity during optimisation.

Leveraging FPGAs for Accelerating Short Read Alignment.

PubMed

Arram, James; Kaplan, Thomas; Luk, Wayne; Jiang, Peiyong

2017-01-01

One of the key challenges facing genomics today is how to efficiently analyze the massive amounts of data produced by next-generation sequencing platforms. With general-purpose computing systems struggling to address this challenge, specialized processors such as the Field-Programmable Gate Array (FPGA) are receiving growing interest. The means by which to leverage this technology for accelerating genomic data analysis is however largely unexplored. In this paper, we present a runtime reconfigurable architecture for accelerating short read alignment using FPGAs. This architecture exploits the reconfigurability of FPGAs to allow the development of fast yet flexible alignment designs. We apply this architecture to develop an alignment design which supports exact and approximate alignment with up to two mismatches. Our design is based on the FM-index, with optimizations to improve the alignment performance. In particular, the n-step FM-index, index oversampling, a seed-and-compare stage, and bi-directional backtracking are included. Our design is implemented and evaluated on a 1U Maxeler MPC-X2000 dataflow node with eight Altera Stratix-V FPGAs. Measurements show that our design is 28 times faster than Bowtie2 running with 16 threads on dual Intel Xeon E5-2640 CPUs, and nine times faster than Soap3-dp running on an NVIDIA Tesla C2070 GPU.

The evaluation model of the enterprise energy efficiency based on DPSR.

PubMed

Wei, Jin-Yu; Zhao, Xiao-Yu; Sun, Xue-Shan

2017-05-08

The reasonable evaluation of the enterprise energy efficiency is an important work in order to reduce the energy consumption. In this paper, an effective energy efficiency evaluation index system is proposed based on DPSR (Driving forces-Pressure-State-Response) with the consideration of the actual situation of enterprises. This index system which covers multi-dimensional indexes of the enterprise energy efficiency can reveal the complete causal chain which includes the "driver forces" and "pressure" of the enterprise energy efficiency "state" caused by the internal and external environment, and the ultimate enterprise energy-saving "response" measures. Furthermore, the ANP (Analytic Network Process) and cloud model are used to calculate the weight of each index and evaluate the energy efficiency level. The analysis of BL Company verifies the feasibility of this index system and also provides an effective way to improve the energy efficiency at last.

An adjoint method of sensitivity analysis for residual vibrations of structures subject to impacts

NASA Astrophysics Data System (ADS)

Yan, Kun; Cheng, Gengdong

2018-03-01

For structures subject to impact loads, the residual vibration reduction is more and more important as the machines become faster and lighter. An efficient sensitivity analysis of residual vibration with respect to structural or operational parameters is indispensable for using a gradient based optimization algorithm, which reduces the residual vibration in either active or passive way. In this paper, an integrated quadratic performance index is used as the measure of the residual vibration, since it globally measures the residual vibration response and its calculation can be simplified greatly with Lyapunov equation. Several sensitivity analysis approaches for performance index were developed based on the assumption that the initial excitations of residual vibration were given and independent of structural design. Since the resulting excitations by the impact load often depend on structural design, this paper aims to propose a new efficient sensitivity analysis method for residual vibration of structures subject to impacts to consider the dependence. The new method is developed by combining two existing methods and using adjoint variable approach. Three numerical examples are carried out and demonstrate the accuracy of the proposed method. The numerical results show that the dependence of initial excitations on structural design variables may strongly affects the accuracy of sensitivities.

G-Hash: Towards Fast Kernel-based Similarity Search in Large Graph Databases.

PubMed

Wang, Xiaohong; Smalter, Aaron; Huan, Jun; Lushington, Gerald H

2009-01-01

Structured data including sets, sequences, trees and graphs, pose significant challenges to fundamental aspects of data management such as efficient storage, indexing, and similarity search. With the fast accumulation of graph databases, similarity search in graph databases has emerged as an important research topic. Graph similarity search has applications in a wide range of domains including cheminformatics, bioinformatics, sensor network management, social network management, and XML documents, among others.Most of the current graph indexing methods focus on subgraph query processing, i.e. determining the set of database graphs that contains the query graph and hence do not directly support similarity search. In data mining and machine learning, various graph kernel functions have been designed to capture the intrinsic similarity of graphs. Though successful in constructing accurate predictive and classification models for supervised learning, graph kernel functions have (i) high computational complexity and (ii) non-trivial difficulty to be indexed in a graph database.Our objective is to bridge graph kernel function and similarity search in graph databases by proposing (i) a novel kernel-based similarity measurement and (ii) an efficient indexing structure for graph data management. Our method of similarity measurement builds upon local features extracted from each node and their neighboring nodes in graphs. A hash table is utilized to support efficient storage and fast search of the extracted local features. Using the hash table, a graph kernel function is defined to capture the intrinsic similarity of graphs and for fast similarity query processing. We have implemented our method, which we have named G-hash, and have demonstrated its utility on large chemical graph databases. Our results show that the G-hash method achieves state-of-the-art performance for k-nearest neighbor (k-NN) classification. Most importantly, the new similarity measurement and the index structure is scalable to large database with smaller indexing size, faster indexing construction time, and faster query processing time as compared to state-of-the-art indexing methods such as C-tree, gIndex, and GraphGrep.

Information sources for obesity prevention policy research: a review of systematic reviews.

PubMed

Hanneke, Rosie; Young, Sabrina K

2017-08-08

Systematic identification of evidence in health policy can be time-consuming and challenging. This study examines three questions pertaining to systematic reviews on obesity prevention policy, in order to identify the most efficient search methods: (1) What percentage of the primary studies selected for inclusion in the reviews originated in scholarly as opposed to gray literature? (2) How much of the primary scholarly literature in this topic area is indexed in PubMed/MEDLINE? (3) Which databases index the greatest number of primary studies not indexed in PubMed, and are these databases searched consistently across systematic reviews? We identified systematic reviews on obesity prevention policy and explored their search methods and citations. We determined the percentage of scholarly vs. gray literature cited, the most frequently cited journals, and whether each primary study was indexed in PubMed. We searched 21 databases for all primary study articles not indexed in PubMed to determine which database(s) indexed the highest number of these relevant articles. In total, 21 systematic reviews were identified. Ten of the 21 systematic reviews reported searching gray literature, and 12 reviews ultimately included gray literature in their analyses. Scholarly articles accounted for 577 of the 649 total primary study papers. Of these, 495 (76%) were indexed in PubMed. Google Scholar retrieved the highest number of the remaining 82 non-PubMed scholarly articles, followed by Scopus and EconLit. The Journal of the American Dietetic Association was the most-cited journal. Researchers can maximize search efficiency by searching a small yet targeted selection of both scholarly and gray literature resources. A highly sensitive search of PubMed and those databases that index the greatest number of relevant articles not indexed in PubMed, namely multidisciplinary and economics databases, could save considerable time and effort. When combined with a gray literature search and additional search methods, including cited reference searching and consulting with experts, this approach could help maintain broad retrieval of relevant studies while improving search efficiency. Findings also have implications for designing specialized databases for public health research.

Challenges and methodology for indexing the computerized patient record.

PubMed

Ehrler, Frédéric; Ruch, Patrick; Geissbuhler, Antoine; Lovis, Christian

2007-01-01

Patient records contain most crucial documents for managing the treatments and healthcare of patients in the hospital. Retrieving information from these records in an easy, quick and safe way helps care providers to save time and find important facts about their patient's health. This paper presents the scalability issues induced by the indexing and the retrieval of the information contained in the patient records. For this study, EasyIR, an information retrieval tool performing full text queries and retrieving the related documents has been used. An evaluation of the performance reveals that the indexing process suffers from overhead consequence of the particular structure of the patient records. Most IR tools are designed to manage very large numbers of documents in a single index whereas in our hypothesis, one index per record, which usually implies few documents, has been imposed. As the number of modifications and creations of patient records are significant in a day, using a specialized and efficient indexation tool is required.

Broadband giant-refractive-index material based on mesoscopic space-filling curves

NASA Astrophysics Data System (ADS)

Chang, Taeyong; Kim, Jong Uk; Kang, Seung Kyu; Kim, Hyowook; Kim, Do Kyung; Lee, Yong-Hee; Shin, Jonghwa

2016-08-01

The refractive index is the fundamental property of all optical materials and dictates Snell's law, propagation speed, wavelength, diffraction, energy density, absorption and emission of light in materials. Experimentally realized broadband refractive indices remain <40, even with intricately designed artificial media. Herein, we demonstrate a measured index >1,800 resulting from a mesoscopic crystal with a dielectric constant greater than three million. This gigantic enhancement effect originates from the space-filling curve concept from mathematics. The principle is inherently very broad band, the enhancement being nearly constant from zero up to the frequency of interest. This broadband giant-refractive-index medium promises not only enhanced resolution in imaging and raised fundamental absorption limits in solar energy devices, but also compact, power-efficient components for optical communication and increased performance in many other applications.

Design and implementation of priority and time-window based traffic scheduling and routing-spectrum allocation mechanism in elastic optical networks

NASA Astrophysics Data System (ADS)

Wang, Honghuan; Xing, Fangyuan; Yin, Hongxi; Zhao, Nan; Lian, Bizhan

2016-02-01

With the explosive growth of network services, the reasonable traffic scheduling and efficient configuration of network resources have an important significance to increase the efficiency of the network. In this paper, an adaptive traffic scheduling policy based on the priority and time window is proposed and the performance of this algorithm is evaluated in terms of scheduling ratio. The routing and spectrum allocation are achieved by using the Floyd shortest path algorithm and establishing a node spectrum resource allocation model based on greedy algorithm, which is proposed by us. The fairness index is introduced to improve the capability of spectrum configuration. The results show that the designed traffic scheduling strategy can be applied to networks with multicast and broadcast functionalities, and makes them get real-time and efficient response. The scheme of node spectrum configuration improves the frequency resource utilization and gives play to the efficiency of the network.

Parallel Index and Query for Large Scale Data Analysis

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

Chou, Jerry; Wu, Kesheng; Ruebel, Oliver

2011-07-18

Modern scientific datasets present numerous data management and analysis challenges. State-of-the-art index and query technologies are critical for facilitating interactive exploration of large datasets, but numerous challenges remain in terms of designing a system for process- ing general scientific datasets. The system needs to be able to run on distributed multi-core platforms, efficiently utilize underlying I/O infrastructure, and scale to massive datasets. We present FastQuery, a novel software framework that address these challenges. FastQuery utilizes a state-of-the-art index and query technology (FastBit) and is designed to process mas- sive datasets on modern supercomputing platforms. We apply FastQuery to processing ofmore » a massive 50TB dataset generated by a large scale accelerator modeling code. We demonstrate the scalability of the tool to 11,520 cores. Motivated by the scientific need to search for inter- esting particles in this dataset, we use our framework to reduce search time from hours to tens of seconds.« less

An Item-Driven Adaptive Design for Calibrating Pretest Items. Research Report. ETS RR-14-38

ERIC Educational Resources Information Center

Ali, Usama S.; Chang, Hua-Hua

2014-01-01

Adaptive testing is advantageous in that it provides more efficient ability estimates with fewer items than linear testing does. Item-driven adaptive pretesting may also offer similar advantages, and verification of such a hypothesis about item calibration was the main objective of this study. A suitability index (SI) was introduced to adaptively…

Performance calculation and simulation system of high energy laser weapon

NASA Astrophysics Data System (ADS)

Wang, Pei; Liu, Min; Su, Yu; Zhang, Ke

2014-12-01

High energy laser weapons are ready for some of today's most challenging military applications. Based on the analysis of the main tactical/technical index and combating process of high energy laser weapon, a performance calculation and simulation system of high energy laser weapon was established. Firstly, the index decomposition and workflow of high energy laser weapon was proposed. The entire system was composed of six parts, including classical target, platform of laser weapon, detect sensor, tracking and pointing control, laser atmosphere propagation and damage assessment module. Then, the index calculation modules were designed. Finally, anti-missile interception simulation was performed. The system can provide reference and basis for the analysis and evaluation of high energy laser weapon efficiency.

A numerical analysis of GeO2-doped multi-step index single-mode fiber for stimulated Brillouin scattering

NASA Astrophysics Data System (ADS)

Xiao, H.; Ren, G.; Dong, Y.; Li, H.; Xiao, S.; Wu, B.; Jian, S.

2018-06-01

A numerical analysis of a GeO2-doped single-mode optical fiber with a multi-step index core toward stimulated Brillouin scattering (SBS) based dual-parameter sensing applications is proposed. Adjusting the parameters in the fiber design, higher-order acoustic modes are sufficiently enhanced, making the fiber feasible for discriminative measurements of temperature and strain in the meantime. Numerical simulations indicate that the Brillouin frequency shifts and peak SBS efficiencies are strongly dependent on the doping concentration and the thickness of low-index ring in the proposed fiber. With appropriate structural and optical parameters, this fiber could support two distinct acoustic modes with comparable peak SBS efficiencies and well-spaced Brillouin frequency shifts. The sensing characteristics contributed by the dual-peak feature in the Brillouin gain spectrum are explored. Calculated accuracies of temperature and strain in simultaneous measurements can be up to 0.64 °C and 15.4 με, respectively. The proposed fiber might have potential applications for long-haul distributed dual-parameter simultaneous measurements.

The research on the design and performance of 7×1 pump combiners

NASA Astrophysics Data System (ADS)

Cao, Yang; Sheng, Quan; Fu, Shijie; Zhang, Haiwei; Bai, Xiaolei; Shi, Wei; Yao, Jianquan

2018-02-01

The 7×1 end-pumped pump combiners employing 105/125 μm multimode fibers as pump fibers are investigated. Based on the results of our theoretical analysis, sufficient taper length (TL) and low refractive index (RI) of the capillary have been adopted to fabricate high transmission efficiency combiners. A 7×1 end-pumped pump combiner with an average transmission efficiency of 98.9% and a total return loss of 1.1‰ is fabricated in experiments, which could find its application in high-power fiber laser systems.

Effective Web and Desktop Retrieval with Enhanced Semantic Spaces

NASA Astrophysics Data System (ADS)

Daoud, Amjad M.

We describe the design and implementation of the NETBOOK prototype system for collecting, structuring and efficiently creating semantic vectors for concepts, noun phrases, and documents from a corpus of free full text ebooks available on the World Wide Web. Automatic generation of concept maps from correlated index terms and extracted noun phrases are used to build a powerful conceptual index of individual pages. To ensure scalabilty of our system, dimension reduction is performed using Random Projection [13]. Furthermore, we present a complete evaluation of the relative effectiveness of the NETBOOK system versus the Google Desktop [8].

The effect of early berthing prospects on the energy efficiency operational index in oil tanker vessels

NASA Astrophysics Data System (ADS)

Acomi, N.; Acomi, O. C.

2016-08-01

Marine pollution is one of the main concerns of our society. In order to reduce air pollution produced by ships, the International Maritime Organization has developed technical, operational and management measures. Part of the operational measures refers to CO2 emissions that contribute to the energy efficiency of the vessel. The difficulty in assessing the energy efficiency of the vessel rests with the diversity of voyage parameters, including quantity of cargo, distance and type of fuel in use. Assessing the energy efficiency of the vessel is thus not a matter of determining the absolute value of the CO2, but of providing a meaningful construct to enable tracking performance trends over time, for the same ship, a fleet of ships or across the industry. This concept is the Energy Efficiency Operational Index, EEOI. The purpose of this study is to analyse the influence of a well predicted voyage on the EEOI value. The method used consists in a comparative analysis of two situations regarding berthing prospects: the real passage plan and an early prediction that supposes the vessel to arrive on time as required. The results of the study represent a monitoring tool for the ship owners to assess the EEOI from the early stage of designing the berthing prospects.

Development of an ultra high performance liquid chromatography method for determining triamcinolone acetonide in hydrogels using the design of experiments/design space strategy in combination with process capability index.

PubMed

Oliva, Alexis; Monzón, Cecilia; Santoveña, Ana; Fariña, José B; Llabrés, Matías

2016-07-01

An ultra high performance liquid chromatography method was developed and validated for the quantitation of triamcinolone acetonide in an injectable ophthalmic hydrogel to determine the contribution of analytical method error in the content uniformity measurement. During the development phase, the design of experiments/design space strategy was used. For this, the free R-program was used as a commercial software alternative, a fast efficient tool for data analysis. The process capability index was used to find the permitted level of variation for each factor and to define the design space. All these aspects were analyzed and discussed under different experimental conditions by the Monte Carlo simulation method. Second, a pre-study validation procedure was performed in accordance with the International Conference on Harmonization guidelines. The validated method was applied for the determination of uniformity of dosage units and the reasons for variability (inhomogeneity and the analytical method error) were analyzed based on the overall uncertainty. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

High-efficiency aperiodic two-dimensional high-contrast-grating hologram

NASA Astrophysics Data System (ADS)

Qiao, Pengfei; Zhu, Li; Chang-Hasnain, Connie J.

2016-03-01

High efficiency phase holograms are designed and implemented using aperiodic two-dimensional (2D) high-contrast gratings (HCGs). With our design algorithm and an in-house developed rigorous coupled-wave analysis (RCWA) package for periodic 2D HCGs, the structural parameters are obtained to achieve a full 360-degree phase-tuning range of the reflected or transmitted wave, while maintaining the power efficiency above 90%. For given far-field patterns or 3D objects to reconstruct, we can generate the near-field phase distribution through an iterative process. The aperiodic HCG phase plates we design for holograms are pixelated, and the local geometric parameters for each pixel to achieve desired phase alternation are extracted from our periodic HCG designs. Our aperiodic HCG holograms are simulated using the 3D finite-difference time-domain method. The simulation results confirm that the desired far-field patterns are successfully produced under illumination at the designed wavelength. The HCG holograms are implemented on the quartz wafers, using amorphous silicon as the high-index material. We propose HCG designs at both visible and infrared wavelengths, and our simulation confirms the reconstruction of 3D objects. The high-contrast gratings allow us to realize low-cost, compact, flat, and integrable holograms with sub-micrometer thicknesses.

Geometric Design of Scalable Forward Scatterers for Optimally Efficient Solar Transformers.

PubMed

Kim, Hye-Na; Vahidinia, Sanaz; Holt, Amanda L; Sweeney, Alison M; Yang, Shu

2017-11-01

It will be ideal to deliver equal, optimally efficient "doses" of sunlight to all cells in a photobioreactor system, while simultaneously utilizing the entire solar resource. Backed by the numerical scattering simulation and optimization, here, the design, synthesis, and characterization of the synthetic iridocytes that recapitulated the salient forward-scattering behavior of the Tridacnid clam system are reported, which presents the first geometric solution to allow narrow, precise forward redistribution of flux, utilizing the solar resource at the maximum quantum efficiency possible in living cells. The synthetic iridocytes are composed of silica nanoparticles in microspheres embedded in gelatin, both are low refractive index materials and inexpensive. They show wavelength selectivity, have little loss (the back-scattering intensity is reduced to less than ≈0.01% of the forward-scattered intensity), and narrow forward scattering cone similar to giant clams. Moreover, by comparing experiments and theoretical calculation, it is confirmed that the nonuniformity of the scatter sizes is a "feature not a bug" of the design, allowing for efficient, forward redistribution of solar flux in a micrometer-scaled paradigm. This method is environmentally benign, inexpensive, and scalable to produce optical components that will find uses in efficiency-limited solar conversion technologies, heat sinks, and biofuel production. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

[Application of Fourier amplitude sensitivity test in Chinese healthy volunteer population pharmacokinetic model of tacrolimus].

PubMed

Guan, Zheng; Zhang, Guan-min; Ma, Ping; Liu, Li-hong; Zhou, Tian-yan; Lu, Wei

2010-07-01

In this study, we evaluated the influence of different variance from each of the parameters on the output of tacrolimus population pharmacokinetic (PopPK) model in Chinese healthy volunteers, using Fourier amplitude sensitivity test (FAST). Besides, we estimated the index of sensitivity within whole course of blood sampling, designed different sampling times, and evaluated the quality of parameters' and the efficiency of prediction. It was observed that besides CL1/F, the index of sensitivity for all of the other four parameters (V1/F, V2/F, CL2/F and k(a)) in tacrolimus PopPK model showed relatively high level and changed fast with the time passing. With the increase of the variance of k(a), its indices of sensitivity increased obviously, associated with significant decrease in sensitivity index for the other parameters, and obvious change in peak time as well. According to the simulation of NONMEM and the comparison among different fitting results, we found that the sampling time points designed according to FAST surpassed the other time points. It suggests that FAST can access the sensitivities of model parameters effectively, and assist the design of clinical sampling times and the construction of PopPK model.

Impact of waste heat recovery systems on energy efficiency improvement of a heavy-duty diesel engine

NASA Astrophysics Data System (ADS)

Ma, Zheshu; Chen, Hua; Zhang, Yong

2017-09-01

The increase of ship's energy utilization efficiency and the reduction of greenhouse gas emissions have been high lightened in recent years and have become an increasingly important subject for ship designers and owners. The International Maritime Organization (IMO) is seeking measures to reduce the CO2 emissions from ships, and their proposed energy efficiency design index (EEDI) and energy efficiency operational indicator (EEOI) aim at ensuring that future vessels will be more efficient. Waste heat recovery can be employed not only to improve energy utilization efficiency but also to reduce greenhouse gas emissions. In this paper, a typical conceptual large container ship employing a low speed marine diesel engine as the main propulsion machinery is introduced and three possible types of waste heat recovery systems are designed. To calculate the EEDI and EEOI of the given large container ship, two software packages are developed. From the viewpoint of operation and maintenance, lowering the ship speed and improving container load rate can greatly reduce EEOI and further reduce total fuel consumption. Although the large container ship itself can reach the IMO requirements of EEDI at the first stage with a reduction factor 10% under the reference line value, the proposed waste heat recovery systems can improve the ship EEDI reduction factor to 20% under the reference line value.

Suspended mid-infrared fiber-to-chip grating couplers for SiGe waveguides

NASA Astrophysics Data System (ADS)

Favreau, Julien; Durantin, Cédric; Fédéli, Jean-Marc; Boutami, Salim; Duan, Guang-Hua

2016-03-01

Silicon photonics has taken great importance owing to the applications in optical communications, ranging from short reach to long haul. Originally dedicated to telecom wavelengths, silicon photonics is heading toward circuits handling with a broader spectrum, especially in the short and mid-infrared (MIR) range. This trend is due to potential applications in chemical sensing, spectroscopy and defense in the 2-10 μm range. We previously reported the development of a MIR photonic platform based on buried SiGe/Si waveguide with propagation losses between 1 and 2 dB/cm. However the low index contrast of the platform makes the design of efficient grating couplers very challenging. In order to achieve a high fiber-to-chip efficiency, we propose a novel grating coupler structure, in which the grating is locally suspended in air. The grating has been designed with a FDTD software. To achieve high efficiency, suspended structure thicknesses have been jointly optimized with the grating parameters, namely the fill factor, the period and the grating etch depth. Using the Efficient Global Optimization (EGO) method we obtained a configuration where the fiber-to-waveguide efficiency is above 57 %. Moreover the optical transition between the suspended and the buried SiGe waveguide has been carefully designed by using an Eigenmode Expansion software. Transition efficiency as high as 86 % is achieved.

Risk management and statistical multivariate analysis approach for design and optimization of satranidazole nanoparticles.

PubMed

Dhat, Shalaka; Pund, Swati; Kokare, Chandrakant; Sharma, Pankaj; Shrivastava, Birendra

2017-01-01

Rapidly evolving technical and regulatory landscapes of the pharmaceutical product development necessitates risk management with application of multivariate analysis using Process Analytical Technology (PAT) and Quality by Design (QbD). Poorly soluble, high dose drug, Satranidazole was optimally nanoprecipitated (SAT-NP) employing principles of Formulation by Design (FbD). The potential risk factors influencing the critical quality attributes (CQA) of SAT-NP were identified using Ishikawa diagram. Plackett-Burman screening design was adopted to screen the eight critical formulation and process parameters influencing the mean particle size, zeta potential and dissolution efficiency at 30min in pH7.4 dissolution medium. Pareto charts (individual and cumulative) revealed three most critical factors influencing CQA of SAT-NP viz. aqueous stabilizer (Polyvinyl alcohol), release modifier (Eudragit® S 100) and volume of aqueous phase. The levels of these three critical formulation attributes were optimized by FbD within established design space to minimize mean particle size, poly dispersity index, and maximize encapsulation efficiency of SAT-NP. Lenth's and Bayesian analysis along with mathematical modeling of results allowed identification and quantification of critical formulation attributes significantly active on the selected CQAs. The optimized SAT-NP exhibited mean particle size; 216nm, polydispersity index; 0.250, zeta potential; -3.75mV and encapsulation efficiency; 78.3%. The product was lyophilized using mannitol to form readily redispersible powder. X-ray diffraction analysis confirmed the conversion of crystalline SAT to amorphous form. In vitro release of SAT-NP in gradually pH changing media showed <20% release in pH1.2 and pH6.8 in 5h, while, complete release (>95%) in pH7.4 in next 3h, indicative of burst release after a lag time. This investigation demonstrated effective application of risk management and QbD tools in developing site-specific release SAT-NP by nanoprecipitation. Copyright © 2016 Elsevier B.V. All rights reserved.

Design of a tubular skylight system

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

Chao, B.L.

1996-10-01

Since its introduction to the US market in 1991, tubular skylight provides a solution to the problem of lighting up dark corners in a house. Over the years, design of similar products has emphasized on quantity alone and attention to a range of other equally important issues: efficient collecting system, selection of higher specular reflectance material, seals, distribution and quality of light, was not noted. In this paper, the fundamental design concept of an efficient tubular skylight and the possibility of collimating diffuse light is reviewed. The importance of specular reflectance of the tube material on the performance of tubularmore » skylight is demonstrated. Visual appearance (quality) of transmitted light down the tube is related in part to the yellowness index of various materials. Discussion of adequacy of current building and energy code requirements on tubular skylights is briefly touched on and energy simulation results based on a numerical code are presented.« less

The Development of More Efficient Measures for Evaluating Language Impairments in Aphasic Patients.

ERIC Educational Resources Information Center

Phillips, Phyllis P.; Halpin, Gerald

Because it generally took over an hour to administer the Porch Index of Communicative Ability (PICA), a shorter but comparable version of the test was developed. The original test was designed to quantify aphasic patients' ability level on common communicative tasks and consisted of 18 ten-item subtests. Each item resulted in a proficiency rating,…

An Ecosystem-Based Approach to Valley Oak Mitigation

Treesearch

Marcus S. Rawlings; Daniel A. Airola

1997-01-01

The Contra Costa Water District’s (CCWD’s) Los Vaqueros Reservoir Project will inundate 180 acres of valley oak habitats. Instead of using replacement ratios to identify mitigation needs, we designed an approach that would efficiently replace lost ecological values. We developed a habitat quality index model to assess the value of lost wildlife habitat and...

Design of a hybrid As₂S₃-Ti:LiNbO₃ optical waveguide for phase-matched difference frequency generation at mid-infrared.

PubMed

Wang, Xin; Madsen, Christi K

2014-11-03

Based on arsenic tri-sulfide films on titanium-diffused lithium niobate, we designed a hybrid optical waveguide for efficient mid-infrared emission by phase-matched difference frequency generation (DFG). The hybrid waveguide structure possesses a low-index magnesium fluoride buffer layer sandwiched between two high-index As(2)S(3) slabs, so that pump and signal waves are tightly confined by titanium-diffused waveguide while the DFG output idler wave at mid-infrared is confined by the whole hybrid waveguide structure. On a 1 mm-long hybrid waveguide pumped at 50 mW powers, a normalized power conversion efficiency of 20.52%W(-1)cm(-2) was theoretically predicted, which is the highest record for mid-infrared DFG waveguides based on lithium niobate crystal, to the best of our knowledge. Using a tunable near-infrared pump laser at 1.38-1.47 µm or a tunable signal laser at 1.95-2.15 µm, a broad mid-infrared tuning range from 4.0 µm to 4.9 µm can be achieved. Such hybrid optical waveguides are feasible for mid-infrared emission with mW powers and sub-nanometer linewidths.

Heterogeneous delivering capability promotes traffic efficiency in complex networks

NASA Astrophysics Data System (ADS)

Zhu, Yan-Bo; Guan, Xiang-Min; Zhang, Xue-Jun

2015-12-01

Traffic is one of the most fundamental dynamical processes in networked systems. With the homogeneous delivery capability of nodes, the global dynamic routing strategy proposed by Ling et al. [Phys. Rev. E81, 016113 (2010)] adequately uses the dynamic information during the process and thus it can reach a quite high network capacity. In this paper, based on the global dynamic routing strategy, we proposed a heterogeneous delivery allocation strategy of nodes on scale-free networks with consideration of nodes degree. It is found that the network capacity as well as some other indexes reflecting transportation efficiency are further improved. Our work may be useful for the design of more efficient routing strategies in communication or transportation systems.

Superenhancers: novel opportunities for nanowire optoelectronics.

PubMed

Khudiyev, Tural; Bayindir, Mehmet

2014-12-16

Nanowires play a crucial role in the development of new generation optoelectronic devices ranging from photovoltaics to photodetectors, as these designs capitalize on the low material usage, utilize leaky-mode optical resonances and possess high conversion efficiencies associated with nanowire geometry. However, their current schemes lack sufficient absorption capacity demanded for their practical applicability, and more efficient materials cannot find widespread usage in these designs due to their rarity and cost. Here we suggest a novel and versatile nanoconcentrator scheme utilizing unique optical features of non-resonant Mie (NRM) scattering regime associated with low-index structures. The scattering regime is highly compatible with resonant Mie absorption effect taking place in nanowire absorbers. This technique in its optimized forms can provide up to 1500% total absorption enhancement, 400-fold material save and is suitable for large-area applications with significant area preservation compared to thin-film of same materials. Proposed superenhancer concept with its exceptional features such as broadband absorption enhancement, polarization immunity and material-independent manner paves the way for development of efficient nanowire photosensors or solar thermophotovoltaic devices and presents novel design opportunities for self-powered nanosystems.

Efficiency optimization of wireless power transmission systems for active capsule endoscopes.

PubMed

Zhiwei, Jia; Guozheng, Yan; Jiangpingping; Zhiwu, Wang; Hua, Liu

2011-10-01

Multipurpose active capsule endoscopes have drawn considerable attention in recent years, but these devices continue to suffer from energy limitations. A wireless power supply system is regarded as a practical way to overcome the power shortage problem in such devices. This paper focuses on the efficiency optimization of a wireless energy supply system with size and safety constraints. A mathematical programming model in which these constraints are considered is proposed for transmission efficiency, optimal frequency and current, and overall system effectiveness. To verify the feasibility of the proposed method, we use a wireless active capsule endoscope as an illustrative example. The achieved efficiency can be regarded as an index for evaluating the system, and the proposed approach can be used to direct the design of transmitting and receiving coils.

Waveguide structures in anisotropic nonlinear crystals

NASA Astrophysics Data System (ADS)

Li, Da; Hong, Pengda; Meissner, Helmuth E.

2017-02-01

We report on the design and manufacturing parameters of waveguiding structures of anisotropic nonlinear crystals that are employed for harmonic conversions, using Adhesive-Free Bonding (AFB®). This technology enables a full range of predetermined refractive index differences that are essential for the design of single mode or low-mode propagation with high efficiency in anisotropic nonlinear crystals which in turn results in compact frequency conversion systems. Examples of nonlinear optical waveguides include periodically bonded walk-off corrected nonlinear optical waveguides and periodically poled waveguide components, such as lithium triborate (LBO), beta barium borate (β-BBO), lithium niobate (LN), potassium titanyl phosphate (KTP), zinc germanium phosphide (ZGP) and silver selenogallate (AGSE). Simulation of planar LN waveguide shows that when the electric field vector E lies in the k-c plane, the power flow is directed precisely along the propagation direction, demonstrating waveguiding effect in the planar waveguide. Employment of anisotropic nonlinear optical waveguides, for example in combination with AFB® crystalline fiber waveguides (CFW), provides access to the design of a number of novel high power and high efficiency light sources spanning the range of wavelengths from deep ultraviolet (as short as 200 nm) to mid-infrared (as long as about 18 μm). To our knowledge, the technique is the only generally applicable one because most often there are no compatible cladding crystals available to nonlinear optical cores, especially not with an engineer-able refractive index difference and large mode area.

Optimization of long circulating mixed polymeric micelles containing vinpocetine using simple lattice mixture design, in vitro and in vivo characterization.

PubMed

El-Dahmy, Rania Moataz; Elsayed, Ibrahim; Elshafeey, Ahmed Hassen; Gawad, Nabaweya Abdelaziz Abd El; El-Gazayerly, Omaima Naim

2014-12-30

The aim of this study was to increase the in vivo mean residence time of vinpocetine after IV injection utilizing long circulating mixed micellar systems. Mixed micelles were prepared using Pluronics L121, P123 and F127. The systems were characterized by testing their entrapment efficiency, particle size, polydispersity index, zeta potential, transmission electron microscopy and in vitro drug release. Simple lattice mixture design was planned for the optimization using Design-Expert(®) software. The optimized formula was lyophilized, sterilized and imaged by scanning electron microscope. Moreover, the in vivo behavior of the optimized formula was evaluated after IV injection in rabbits. The optimized formula, containing 68% w/w Pluronic L121 and 32% w/w Pluronic F127, had the highest desirability value (0.621). Entrapment efficiency, particle size, polydispersity index and zeta potential of the optimized formula were 50.74 ± 3.26%, 161.50 ± 7.39 nm, 0.21 ± 0.03 and -22.42 ± 1.72 mV, respectively. Lyophilization and sterilization did not affect the characteristics of the optimized formula. Upon in vivo investigation in rabbits, the optimized formula showed a significantly higher elimination half-life and mean residence time than the market product. Finally, mixed micelles could be considered as a promising long circulating nanocarrier for lipophilic drugs. Copyright © 2014 Elsevier B.V. All rights reserved.

Designing and assessing weather-based financial hedging contracts to mitigate water conflicts at the river basin scale. A case study in the Italian Alps

NASA Astrophysics Data System (ADS)

Bellagamba, Laura; Denaro, Simona; Kern, Jordan; Giuliani, Matteo; Castelletti, Andrea; Characklis, Gregory

2016-04-01

Growing water demands and more frequent and severe droughts are increasingly challenging water management in many regions worldwide, exacerbating water disputes and reducing the space for negotiated agreements at the catchment scale. In the lack of a centralized controller, the design and deployment of coordination and/or regulatory mechanisms is a way to improve system-wide efficiency while preserving the distributed nature of the decision making setting, and facilitating cooperation among institutionally independent decision-makers. Recent years have witnessed an increased interest in index-based insurance contracts as mechanisms for sharing hydro-meteorological risk in complex and heterogeneous decision making context (e.g. multiple stakeholders and institutionally independent decision makers). In this study, we explore the potential for index-based insurance contracts to mitigate the conflict in a water system characterized by (political) power asymmetry between hydropower companies upstream and farmers downstream. The Lake Como basin in the Italian Alps is considered as a case study. We generated alternative regulatory mechanisms in the form of minimum release constraints to the hydropower facilities, and designed an insurance contract for hedging against hydropower relative revenue losses. The fundamental step in designing this type of insurance contracts is the identification of a suitable index, which triggers the payouts as well as the payout function, defined by strike level and slope (e.g., euros/index unit). A portfolio of index-based contracts was designed for the case study and evaluated in terms of revenue floor, basis risk and revenue fluctuation around the mean, both with and without insurance. Over the long term, the insurance proved to be capable to keep the minimum revenue above a specified level while providing a greater certainty on the revenue trend. This result shows the possibility to augment farmer's supply with little loss for hydropower companies, thus helping in mitigating the conflict between the stakeholders.

Index to Estimate the Efficiency of an Ophthalmic Practice.

PubMed

Chen, Andrew; Kim, Eun Ah; Aigner, Dennis J; Afifi, Abdelmonem; Caprioli, Joseph

2015-08-01

A metric of efficiency, a function of the ratio of quality to cost per patient, will allow the health care system to better measure the impact of specific reforms and compare the effectiveness of each. To develop and evaluate an efficiency index that estimates the performance of an ophthalmologist's practice as a function of cost, number of patients receiving care, and quality of care. Retrospective review of 36 ophthalmology subspecialty practices from October 2011 to September 2012 at a university-based eye institute. The efficiency index (E) was defined as a function of adjusted number of patients (N(a)), total practice adjusted costs (C(a)), and a preliminary measure of quality (Q). Constant b limits E between 0 and 1. Constant y modifies the influence of Q on E. Relative value units and geographic cost indices determined by the Centers for Medicare and Medicaid for 2012 were used to calculate adjusted costs. The efficiency index is expressed as the following: E = b(N(a)/C(a))Q(y). Independent, masked auditors reviewed 20 random patient medical records for each practice and filled out 3 questionnaires to obtain a process-based quality measure. The adjusted number of patients, adjusted costs, quality, and efficiency index were calculated for 36 ophthalmology subspecialties. The median adjusted number of patients was 5516 (interquartile range, 3450-11,863), the median adjusted cost was 1.34 (interquartile range, 0.99-1.96), the median quality was 0.89 (interquartile range, 0.79-0.91), and the median value of the efficiency index was 0.26 (interquartile range, 0.08-0.42). The described efficiency index is a metric that provides a broad overview of performance for a variety of ophthalmology specialties as estimated by resources used and a preliminary measure of quality of care provided. The results of the efficiency index could be used in future investigations to determine its sensitivity to detect the impact of interventions on a practice such as training modules or practice restructuring.

Challenges in measuring feed efficiency

USDA-ARS?s Scientific Manuscript database

The term feed efficiency is vague, and is defined differently by people. Historically, feed efficiency has been defined as the feed:gain (F:G) ratio or the inverse (G:F). Indexes have been developed to rank animals for feed efficiency. These indexes include residual feed intake (RFI) and residual...

Evaluating and optimizing horticultural regimes in space plant growth facilities

NASA Astrophysics Data System (ADS)

Berkovich, Y.; Chetirkin, R.; Wheeler, R.; Sager, J.

In designing innovative Space Plant Growth Facilities (SPGF) for long duration space f ightl various limitations must be addressed including onboard resources: volume, energy consumption, heat transfer and crew labor expenditure. The required accuracy in evaluating onboard resources by using the equivalent mass methodology and applying it to the design of such facilities is not precise. This is due to the uncertainty of the structure and not completely understanding of the properties of all associated hardware, including the technology in these systems. We present a simple criteria of optimization for horticultural regimes in SPGF: Qmax = max [M · (EBI) 2 / (V · E · T) ], where M is the crop harvest in terms of total dry biomass in the plant growth system; EBI is the edible biomass index (harvest index), V is a volume occupied by the crop; E is the crop light energy supply during growth; T is the crop growth duration. The criterion reflects directly on the consumption of onboard resources for crop production. We analyzed the efficiency of plant crops and the environmental parameters by examining the criteria for 15 salad and 12 wheat crops from the data in the ALS database at Kennedy Space Center. Some following conclusion have been established: 1. The technology involved in growing salad crops on a cylindrical type surface provides a more meaningful Q-criterion; 2. Wheat crops were less efficient than leafy greens (salad crops) when examining resource utilization; 3. By increasing light intensity of the crop the efficiency of the resource utilization could decrease. Using the existing databases and Q-criteria we have found that the criteria can be used in optimizing design and horticultural regimes in the SPGF.

The use of the bicycle compatibility index in identifying gaps and deficiencies in bicycle networks

NASA Astrophysics Data System (ADS)

Ilie, A.; Oprea, C.; Costescu, D.; Roşca, E.; Dinu, O.; Ghionea, F.

2016-11-01

Currently, no methodology is widely accepted by engineers, planners, or bicycle coordinators that allow them to determine how compatible a roadway is in providing efficient operation of both bicycles and motor vehicles. Previous studies reported a number of approaches to obtain an appropriate level of service; some authors developed the bicycle level of service (BLOS) and other authors developed the bicycle compatibility indexes (BCI). The level of service (BLOS) for a bicycle route represents an evaluation of safety and commodity perceived by a bicyclist reported to the motorized traffic, while running on the road surface. The bicycle compatibility index (BCI) is used by bicycle coordinators, transportation planners, traffic engineers to evaluate the capability of specific roadways to accommodate both motorists and bicyclists and to plan for and design roadways that are bicycle compatible. After applying BCI and BLOS models for the designed bicycle infrastructure network in the city of Dej, one can see that only few streets are Moderately Low compatible compared to the others with a high degree of compatibility that recommends to include them in the bicycle infrastructure network.

Control of crystal growth in water purification by directional freeze crystallization

NASA Technical Reports Server (NTRS)

Conlon, William M. (Inventor)

1996-01-01

A Directional Freeze Crystallization system employs an indirect contact heat exchanger to freeze a fraction of liquid to be purified. The unfrozen fraction is drained away and the purified frozen fraction is melted. The heat exchanger must be designed in accordance with a Growth Habit Index to achieve efficient separation of contaminants. If gases are dissolved in the liquid, the system must be pressurized.

Acoustic focusing by symmetrical self-bending beams with phase modulations

NASA Astrophysics Data System (ADS)

Gao, He; Gu, Zhong-ming; Liang, Bin; Zou, Xin-ye; Yang, Jing; Yang, Jun; Cheng, Jian-chun

2016-02-01

We propose a scheme for generating high-efficient acoustic focusing capable of circumventing obstacles in the propagating medium. This distinct feature that is highly desirable for practical applications is realized by employing two symmetrical Airy beams, and a different type of acoustic lens is designed by using a zero-index medium to provide the required phase profile with extremely high resolution. Furthermore, the scheme has the flexibility of generating tunable focal length. We anticipate our design to open possibilities for the design of acoustic lens and have potential applications in various important scenarios such as biomedical imaging/therapy and non-destructive evaluation.

Design of a high-power Nd:YAG Q-switched laser cavity

NASA Astrophysics Data System (ADS)

Singh, Ikbal; Kumar, Avinash; Nijhawan, O. P.

1995-06-01

An electro-optically Q-switched Nd:YAG laser resonator that uses two end prisms placed orthogonally perpendicular to each other has been designed. This configuration improves the stability of the resonator and does not alter the characteristics of the electro-optical Q switch. The outcoupling ratio of the cavity is optimized by a change in the azimuthal angle of a phase-matched Porro prism placed at one end of the cavity. The prism placed at the other end of the cavity is designed so that it introduces a phase change of Pi , regardless of its orientation and index of refraction, resulting in a more efficient and stable cavity.

Efficient Light Extraction of Organic Light-Emitting Diodes on a Fully Solution-Processed Flexible Substrate

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

Tong, Kwing; Liu, Xiaofeng; Zhao, Fangchao

A flexible, nanocomposite substrate for maximizing light outcoupling efficiencies of organic light-emitting diodes (OLEDs) is introduced. In depth investigation is performed on designing the integrated strategy based on considerations of surface conductivity, microcavity tuning, and internal light scattering. The resulting nanocomposite substrate consists of silver nanowires as the electrode and a high-index polymer layer and a light-scattering layer for light extraction. It is able to outcouple both the waveguide and the substrate modes, two modes accounting for significant losses in OLED device efficiency. With enhanced light outcoupling, white OLEDs subsequently fabricated on the nanocomposite substrates demonstrate performance metrics of 107more » lm W -1 power efficiency and 49% external quantum efficiency at 1000 cd m -2. Thus, the nanocomposite substrate is fabricated by solution processes at low temperatures for potentially low manufacturing cost.« less

Efficient Light Extraction of Organic Light-Emitting Diodes on a Fully Solution-Processed Flexible Substrate

DOE PAGES

Tong, Kwing; Liu, Xiaofeng; Zhao, Fangchao; ...

2017-07-18

A flexible, nanocomposite substrate for maximizing light outcoupling efficiencies of organic light-emitting diodes (OLEDs) is introduced. In depth investigation is performed on designing the integrated strategy based on considerations of surface conductivity, microcavity tuning, and internal light scattering. The resulting nanocomposite substrate consists of silver nanowires as the electrode and a high-index polymer layer and a light-scattering layer for light extraction. It is able to outcouple both the waveguide and the substrate modes, two modes accounting for significant losses in OLED device efficiency. With enhanced light outcoupling, white OLEDs subsequently fabricated on the nanocomposite substrates demonstrate performance metrics of 107more » lm W -1 power efficiency and 49% external quantum efficiency at 1000 cd m -2. Thus, the nanocomposite substrate is fabricated by solution processes at low temperatures for potentially low manufacturing cost.« less

Model Evaluation To Measuring Efficiencies of ICT Development In Indonesia Region Using DEA

NASA Astrophysics Data System (ADS)

Efendi, Syahril; Fadly Syahputra, M.; Anggia Muchtar, M.

2018-01-01

ICT Pura or digital city is a program designed by the Indonesian government with the main objective is to determine the level of readiness of each district and city in each province in the era of digital economy. It is necessarily to evaluate whether a city or a region that was successfully managing ICT better than other city and significantly contributes to the communities and living systems. Data envelopment analysis (DEA) is a well known technique to estimate efficiency and returns to scale through the construction of a best practice frontier, based on non-parametric mathematical programming approach. This paper addresses DEA BCC method to get index of efficiencies for all region in Indonesia covered by ICT Pura. Numerical result is given.

Performance index and meta-optimization of a direct search optimization method

NASA Astrophysics Data System (ADS)

Krus, P.; Ölvander, J.

2013-10-01

Design optimization is becoming an increasingly important tool for design, often using simulation as part of the evaluation of the objective function. A measure of the efficiency of an optimization algorithm is of great importance when comparing methods. The main contribution of this article is the introduction of a singular performance criterion, the entropy rate index based on Shannon's information theory, taking both reliability and rate of convergence into account. It can also be used to characterize the difficulty of different optimization problems. Such a performance criterion can also be used for optimization of the optimization algorithms itself. In this article the Complex-RF optimization method is described and its performance evaluated and optimized using the established performance criterion. Finally, in order to be able to predict the resources needed for optimization an objective function temperament factor is defined that indicates the degree of difficulty of the objective function.

Mean of the typical decoding rates: a new translation efficiency index based on the analysis of ribosome profiling data.

PubMed

Dana, Alexandra; Tuller, Tamir

2014-12-01

Gene translation modeling and prediction is a fundamental problem that has numerous biomedical implementations. In this work we present a novel, user-friendly tool/index for calculating the mean of the typical decoding rates that enables predicting translation elongation efficiency of protein coding genes for different tissue types, developmental stages, and experimental conditions. The suggested translation efficiency index is based on the analysis of the organism's ribosome profiling data. This index could be used for example to predict changes in translation elongation efficiency of lowly expressed genes that usually have relatively low and/or biased ribosomal densities and protein levels measurements, or can be used for example for predicting translation efficiency of new genetically engineered genes. We demonstrate the usability of this index via the analysis of six organisms in different tissues and developmental stages. Distributable cross platform application and guideline are available for download at: http://www.cs.tau.ac.il/~tamirtul/MTDR/MTDR_Install.html. Copyright © 2015 Dana and Tuller.

Performance of toxicity probability interval based designs in contrast to the continual reassessment method

PubMed Central

Horton, Bethany Jablonski; Wages, Nolan A.; Conaway, Mark R.

2016-01-01

Toxicity probability interval designs have received increasing attention as a dose-finding method in recent years. In this study, we compared the two-stage, likelihood-based continual reassessment method (CRM), modified toxicity probability interval (mTPI), and the Bayesian optimal interval design (BOIN) in order to evaluate each method's performance in dose selection for Phase I trials. We use several summary measures to compare the performance of these methods, including percentage of correct selection (PCS) of the true maximum tolerable dose (MTD), allocation of patients to doses at and around the true MTD, and an accuracy index. This index is an efficiency measure that describes the entire distribution of MTD selection and patient allocation by taking into account the distance between the true probability of toxicity at each dose level and the target toxicity rate. The simulation study considered a broad range of toxicity curves and various sample sizes. When considering PCS, we found that CRM outperformed the two competing methods in most scenarios, followed by BOIN, then mTPI. We observed a similar trend when considering the accuracy index for dose allocation, where CRM most often outperformed both the mTPI and BOIN. These trends were more pronounced with increasing number of dose levels. PMID:27435150

Design and characterization of 16-mode PANDA polarization-maintaining few-mode ring-core fiber for spatial division multiplexing

NASA Astrophysics Data System (ADS)

Cao, Yuan; Zhao, Yongli; Yu, Xiaosong; Han, Jiawei; Zhang, Jie

2017-11-01

A PANDA polarization-maintaining few-mode ring-core fiber (PM-FM-RCF) structure with two air holes around the ring core is proposed. The relative mode multiplicity factor (RMMF) is defined to evaluate the spatial efficiency of the designed PM-FM-RCF. The performance analysis and comparison of the proposed PANDA PM-FM-RCFs considering three different types of step-index profiles are detailed. Through modal characteristic analysis and numerical simulation, the PM-FM-RCF with a lower refractive index difference (Δnoi=1.5%) between the ring core and the inner central circle can support up to 16 polarization modes with large RMMF at C-band, which shows the optimum modal properties compared with the PM-FM-RCF with higher Δnoi. All the supported polarization modes are effectively separated from their adjacent polarization modes with effective refractive index differences (Δn) larger than 10-4, which also show relatively small chromatic dispersion (-20 to 25 ps/nm/km), low attenuation (<1.4 dB/km), and small bending radius (˜8 mm) over the C-band. The designed PM-FM-RCF can be compatible with standard single-mode fibers and applied in multiple-input multiple-output-free spatial division multiplexing optical networks for short-reach optical interconnection.

Frontal-temporal synchronization of EEG signals quantified by order patterns cross recurrence analysis during propofol anesthesia.

PubMed

Shalbaf, Reza; Behnam, Hamid; Sleigh, Jamie W; Steyn-Ross, D Alistair; Steyn-Ross, Moira L

2015-05-01

Characterizing brain dynamics during anesthesia is a main current challenge in anesthesia study. Several single channel electroencephalogram (EEG)-based commercial monitors like the Bispectral index (BIS) have suggested to examine EEG signal. But, the BIS index has obtained numerous critiques. In this study, we evaluate the concentration-dependent effect of the propofol on long-range frontal-temporal synchronization of EEG signals collected from eight subjects during a controlled induction and recovery design. We used order patterns cross recurrence plot and provide an index named order pattern laminarity (OPL) to assess changes in neuronal synchronization as the mechanism forming the foundation of conscious perception. The prediction probability of 0.9 and 0.84 for OPL and BIS specified that the OPL index correlated more strongly with effect-site propofol concentration. Also, our new index makes faster reaction to transients in EEG recordings based on pharmacokinetic and pharmacodynamic model parameters and demonstrates less variability at the point of loss of consciousness (standard deviation of 0.04 for OPL compared with 0.09 for BIS index). The result show that the OPL index can estimate anesthetic state of patient more efficiently than the BIS index in lightly sedated state with more tolerant of artifacts.

Deterministic binary vectors for efficient automated indexing of MEDLINE/PubMed abstracts.

PubMed

Wahle, Manuel; Widdows, Dominic; Herskovic, Jorge R; Bernstam, Elmer V; Cohen, Trevor

2012-01-01

The need to maintain accessibility of the biomedical literature has led to development of methods to assist human indexers by recommending index terms for newly encountered articles. Given the rapid expansion of this literature, it is essential that these methods be scalable. Document vector representations are commonly used for automated indexing, and Random Indexing (RI) provides the means to generate them efficiently. However, RI is difficult to implement in real-world indexing systems, as (1) efficient nearest-neighbor search requires retaining all document vectors in RAM, and (2) it is necessary to maintain a store of randomly generated term vectors to index future documents. Motivated by these concerns, this paper documents the development and evaluation of a deterministic binary variant of RI. The increased capacity demonstrated by binary vectors has implications for information retrieval, and the elimination of the need to retain term vectors facilitates distributed implementations, enhancing the scalability of RI.

Deterministic Binary Vectors for Efficient Automated Indexing of MEDLINE/PubMed Abstracts

PubMed Central

Wahle, Manuel; Widdows, Dominic; Herskovic, Jorge R.; Bernstam, Elmer V.; Cohen, Trevor

2012-01-01

The need to maintain accessibility of the biomedical literature has led to development of methods to assist human indexers by recommending index terms for newly encountered articles. Given the rapid expansion of this literature, it is essential that these methods be scalable. Document vector representations are commonly used for automated indexing, and Random Indexing (RI) provides the means to generate them efficiently. However, RI is difficult to implement in real-world indexing systems, as (1) efficient nearest-neighbor search requires retaining all document vectors in RAM, and (2) it is necessary to maintain a store of randomly generated term vectors to index future documents. Motivated by these concerns, this paper documents the development and evaluation of a deterministic binary variant of RI. The increased capacity demonstrated by binary vectors has implications for information retrieval, and the elimination of the need to retain term vectors facilitates distributed implementations, enhancing the scalability of RI. PMID:23304369

Privacy preserving index for encrypted electronic medical records.

PubMed

Chen, Yu-Chi; Horng, Gwoboa; Lin, Yi-Jheng; Chen, Kuo-Chang

2013-12-01

With the development of electronic systems, privacy has become an important security issue in real-life. In medical systems, privacy of patients' electronic medical records (EMRs) must be fully protected. However, to combine the efficiency and privacy, privacy preserving index is introduced to preserve the privacy, where the EMR can be efficiently accessed by this patient or specific doctor. In the literature, Goh first proposed a secure index scheme with keyword search over encrypted data based on a well-known primitive, Bloom filter. In this paper, we propose a new privacy preserving index scheme, called position index (P-index), with keyword search over the encrypted data. The proposed index scheme is semantically secure against the adaptive chosen keyword attack, and it also provides flexible space, lower false positive rate, and search privacy. Moreover, it does not rely on pairing, a complicate computation, and thus can search over encrypted electronic medical records from the cloud server efficiently.

Optimization of torque on an optically driven micromotor by manipulation of the index of refraction

NASA Astrophysics Data System (ADS)

Wing, Frank M., III; Mahajan, Satish; Collett, Walter

2004-12-01

Since the 1970"s, the focused laser beam has become a familiar tool to manipulate neutral, dielectric micro-objects. A number of authors, including Higurashi and Gauthier, have described the effects of radiation pressure from laser light on microrotors. Collett, et al. developed a wave, rather than a ray optic, approach in the calculation of such forces on a microrotor for the first time. This paper describes a modification to the design of a laser driven, radiation pressure microrotor, intended to improve the optically generated torque. Employing the wave approach, the electric and magnetic fields in the vicinity of the rotor are calculated using the finite difference time domain (FDTD) method, which takes into account the wave nature of the incident light. Forces are calculated from the application of Maxwell"s stress tensor over the surfaces of the rotor. Results indicate a significant increase in torque when the index of refraction of the microrotor is changed from a single value to an inhomogeneous profile. The optical fiber industry has successfully employed a variation in the index of refraction across the cross section of a fiber for the purpose of increasing the efficiency of light transmission. Therefore, it is hoped that various fabrication methods can be utilized for causing desired changes in the index of refraction of an optically driven microrotor. Various profiles of the index of refraction inside a microrotor are considered for optimization of torque. Simulation methodology and results of torque on a microrotor for various profiles of the index of refraction are presented. Guidelines for improvised fabrication of efficient microrotors may then be obtained from these profiles.

Properties of Chirped Grating Lenses in Optical Waveguides.

DTIC Science & Technology

1984-10-01

the design, the materials and the fabrication q process. In this report, we will summarize the research results obtained at UCSD on the fundamental...limitations of their performance in efficiency, angular field of view and F-number caused by diffraction, materials properties and fabrication techniques... material index, the grating groove pattern in both the transverse and the longitudinal direction and the profile of the grooves can all be varied, while in

Designing a multi-petabyte database for LSST

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

Becla, J; Hanushevsky, A

2005-12-21

The 3.2 giga-pixel LSST camera will produce over half a petabyte of raw images every month. This data needs to be reduced in under a minute to produce real-time transient alerts, and then cataloged and indexed to allow efficient access and simplify further analysis. The indexed catalogs alone are expected to grow at a speed of about 600 terabytes per year. The sheer volume of data, the real-time transient alerting requirements of the LSST, and its spatio-temporal aspects require cutting-edge techniques to build an efficient data access system at reasonable cost. As currently envisioned, the system will rely on amore » database for catalogs and metadata. Several database systems are being evaluated to understand how they will scale and perform at these data volumes in anticipated LSST access patterns. This paper describes the LSST requirements, the challenges they impose, the data access philosophy, and the database architecture that is expected to be adopted in order to meet the data challenges.« less

CMOS-compatible spot-size converter for optical fiber to sub-μm silicon waveguide coupling with low-loss low-wavelength dependence and high tolerance to misalignment

NASA Astrophysics Data System (ADS)

Picard, Marie-Josée.; Latrasse, Christine; Larouche, Carl; Painchaud, Yves; Poulin, Michel; Pelletier, François; Guy, Martin

2016-03-01

One of the biggest challenges of silicon photonics is the efficient coupling of light between the sub-micron SiP waveguides and a standard optical fiber (SMF-28). We recently proposed a novel approach based on a spot-size converter (SSC) that fulfills this need. The SSC integrates a tapered silicon waveguide and a superimposed structure made of a plurality of rods of high index material, disposed in an array-like configuration and embedded in a cladding of lower index material. This superimposed structure defines a waveguide designed to provide an efficient adiabatic transfer, through evanescent coupling, to a 220 nm thick Si waveguide tapered down to a narrow tip on one side, while providing a large mode overlap to the optical fiber on the other side. An initial demonstration was made using a SSC fabricated with post-processing steps. Great coupling to a SMF-28 fiber with a loss of 0.6 dB was obtained for TEpolarized light at 1550 nm with minimum wavelength dependence. In this paper, SSCs designed for operation at 1310 and 1550 nm for TE/TM polarizations and entirely fabricated in a CMOS fab are presented.

Spatial dispersion of index components required for building invisibility cloak medium from photonic crystals

NASA Astrophysics Data System (ADS)

Jamilan, Saeid; Semouchkin, George; Gandji, Navid P.; Semouchkina, Elena

2018-04-01

The opportunities to use dielectric photonic crystals (PhCs) as the media of cylindrical invisibility cloaks, designed using transformation optics (TO) concepts, are investigated. It is shown that TO-based prescriptions for radial index dispersion, responsible for turning waves around hidden objects, can be dropped if the PhC media support self-collimation of waves in bent crystals. Otherwise, to provide prescribed anisotropy of index dispersion, it is possible to employ PhCs with rectangular lattices. It is found, however, that at acceptable cloak thicknesses, modifications of crystal parameters do not allow for achieving the prescribed level of index anisotropy. This problem is solved by finding the reduced spatial dispersion law for the radial index component, which is characterized by decreased against TO-prescriptions values near the target and increased values in outer layers of the cloak. The cloak utilizing reduced prescriptions for indices is shown to perform almost as efficiently as a TO-based cloak, in terms of both wave front restoration behind the target and reducing the total scattering cross-width of the target.

Optimization of the acoustic absorption coefficients of certain functional absorbents

NASA Technical Reports Server (NTRS)

Pocsa, V.; Biborosch, L.; Veres, A.; Halpert, E.; Lorian, R.; Botos, T.

1974-01-01

The sound absorption coefficients of some functional absorbents (mineral wool plates) are determined by the reverberation chamber method. The influence of the angle of inclination of the sound absorbing material with respect to the surface to be treated is analyzed as well as the influence of the covering index, defined as the ratio of the designed area of a plate and the area of the treated surface belonging to another plate. As compared with the conventional method of applying sound-absorbing plates, the analyzed structures have a higher technological and economical efficiency. The optimum structure corresponds to an angle of inclination of 15 deg and a covering index of 0.8.

Design of a sector bowtie nano-rectenna for optical power and infrared detection

NASA Astrophysics Data System (ADS)

Wang, Kai; Hu, Haifeng; Lu, Shan; Guo, Lingju; He, Tao

2015-10-01

We designed a sector bowtie nanoantenna integrated with a rectifier (Au-TiO x -Ti diode) for collecting infrared energy. The optical performance of the metallic bowtie nanoantenna was numerically investigated at infrared frequencies (5-30 μm) using three-dimensional frequency-domain electromagnetic field calculation software based on the finite element method. The simulation results indicate that the resonance wavelength and local field enhancement are greatly affected by the shape and size of the bowtie nanoantenna, as well as the relative permittivity and conductivity of the dielectric layer. The output current of the rectified nano-rectenna is substantially at nanoampere magnitude with an electric field intensity of 1 V/m. Moreover, the power conversion efficiency for devices with three different substrates illustrates that a substrate with a larger refractive index yields a higher efficiency and longer infrared response wavelength. Consequently, the optimized structure can provide theoretical support for the design of novel optical rectennas and fabrication of optoelectronic devices.

An Improved B+ Tree for Flash File Systems

NASA Astrophysics Data System (ADS)

Havasi, Ferenc

Nowadays mobile devices such as mobile phones, mp3 players and PDAs are becoming evermore common. Most of them use flash chips as storage. To store data efficiently on flash, it is necessary to adapt ordinary file systems because they are designed for use on hard disks. Most of the file systems use some kind of search tree to store index information, which is very important from a performance aspect. Here we improved the B+ search tree algorithm so as to make flash devices more efficient. Our implementation of this solution saves 98%-99% of the flash operations, and is now the part of the Linux kernel.

Damage tolerance and structural monitoring for wind turbine blades

PubMed Central

McGugan, M.; Pereira, G.; Sørensen, B. F.; Toftegaard, H.; Branner, K.

2015-01-01

The paper proposes a methodology for reliable design and maintenance of wind turbine rotor blades using a condition monitoring approach and a damage tolerance index coupling the material and structure. By improving the understanding of material properties that control damage propagation it will be possible to combine damage tolerant structural design, monitoring systems, inspection techniques and modelling to manage the life cycle of the structures. This will allow an efficient operation of the wind turbine in terms of load alleviation, limited maintenance and repair leading to a more effective exploitation of offshore wind. PMID:25583858

An optimal routing strategy on scale-free networks

NASA Astrophysics Data System (ADS)

Yang, Yibo; Zhao, Honglin; Ma, Jinlong; Qi, Zhaohui; Zhao, Yongbin

Traffic is one of the most fundamental dynamical processes in networked systems. With the traditional shortest path routing (SPR) protocol, traffic congestion is likely to occur on the hub nodes on scale-free networks. In this paper, we propose an improved optimal routing (IOR) strategy which is based on the betweenness centrality and the degree centrality of nodes in the scale-free networks. With the proposed strategy, the routing paths can accurately bypass hub nodes in the network to enhance the transport efficiency. Simulation results show that the traffic capacity as well as some other indexes reflecting transportation efficiency are further improved with the IOR strategy. Owing to the significantly improved traffic performance, this study is helpful to design more efficient routing strategies in communication or transportation systems.

Optimal sampling design for estimating spatial distribution and abundance of a freshwater mussel population

USGS Publications Warehouse

Pooler, P.S.; Smith, D.R.

2005-01-01

We compared the ability of simple random sampling (SRS) and a variety of systematic sampling (SYS) designs to estimate abundance, quantify spatial clustering, and predict spatial distribution of freshwater mussels. Sampling simulations were conducted using data obtained from a census of freshwater mussels in a 40 X 33 m section of the Cacapon River near Capon Bridge, West Virginia, and from a simulated spatially random population generated to have the same abundance as the real population. Sampling units that were 0.25 m 2 gave more accurate and precise abundance estimates and generally better spatial predictions than 1-m2 sampling units. Systematic sampling with ???2 random starts was more efficient than SRS. Estimates of abundance based on SYS were more accurate when the distance between sampling units across the stream was less than or equal to the distance between sampling units along the stream. Three measures for quantifying spatial clustering were examined: Hopkins Statistic, the Clumping Index, and Morisita's Index. Morisita's Index was the most reliable, and the Hopkins Statistic was prone to false rejection of complete spatial randomness. SYS designs with units spaced equally across and up stream provided the most accurate predictions when estimating the spatial distribution by kriging. Our research indicates that SYS designs with sampling units equally spaced both across and along the stream would be appropriate for sampling freshwater mussels even if no information about the true underlying spatial distribution of the population were available to guide the design choice. ?? 2005 by The North American Benthological Society.

Spatial Indexing for Data Searching in Mobile Sensing Environments.

PubMed

Zhou, Yuchao; De, Suparna; Wang, Wei; Moessner, Klaus; Palaniswami, Marimuthu S

2017-06-18

Data searching and retrieval is one of the fundamental functionalities in many Web of Things applications, which need to collect, process and analyze huge amounts of sensor stream data. The problem in fact has been well studied for data generated by sensors that are installed at fixed locations; however, challenges emerge along with the popularity of opportunistic sensing applications in which mobile sensors keep reporting observation and measurement data at variable intervals and changing geographical locations. To address these challenges, we develop the Geohash-Grid Tree, a spatial indexing technique specially designed for searching data integrated from heterogeneous sources in a mobile sensing environment. Results of the experiments on a real-world dataset collected from the SmartSantander smart city testbed show that the index structure allows efficient search based on spatial distance, range and time windows in a large time series database.

Spatial Indexing for Data Searching in Mobile Sensing Environments

PubMed Central

Zhou, Yuchao; De, Suparna; Wang, Wei; Moessner, Klaus; Palaniswami, Marimuthu S.

2017-01-01

Data searching and retrieval is one of the fundamental functionalities in many Web of Things applications, which need to collect, process and analyze huge amounts of sensor stream data. The problem in fact has been well studied for data generated by sensors that are installed at fixed locations; however, challenges emerge along with the popularity of opportunistic sensing applications in which mobile sensors keep reporting observation and measurement data at variable intervals and changing geographical locations. To address these challenges, we develop the Geohash-Grid Tree, a spatial indexing technique specially designed for searching data integrated from heterogeneous sources in a mobile sensing environment. Results of the experiments on a real-world dataset collected from the SmartSantander smart city testbed show that the index structure allows efficient search based on spatial distance, range and time windows in a large time series database. PMID:28629156

Spectrum splitting using multi-layer dielectric meta-surfaces for efficient solar energy harvesting

NASA Astrophysics Data System (ADS)

Yao, Yuhan; Liu, He; Wu, Wei

2014-06-01

We designed a high-efficiency dispersive mirror based on multi-layer dielectric meta-surfaces. By replacing the secondary mirror of a dome solar concentrator with this dispersive mirror, the solar concentrator can be converted into a spectrum-splitting photovoltaic system with higher energy harvesting efficiency and potentially lower cost. The meta-surfaces are consisted of high-index contrast gratings (HCG). The structures and parameters of the dispersive mirror (i.e. stacked HCG) are optimized based on finite-difference time-domain and rigorous coupled-wave analysis method. Our numerical study shows that the dispersive mirror can direct light with different wavelengths into different angles in the entire solar spectrum, maintaining very low energy loss. Our approach will not only improve the energy harvesting efficiency, but also lower the cost by using single junction cells instead of multi-layer tandem solar cells. Moreover, this approach has the minimal disruption to the existing solar concentrator infrastructures.

Very low color-temperature organic light-emitting diodes for lighting at night

NASA Astrophysics Data System (ADS)

Jou, Jwo-Huei; Tang, Ming-Chun; Chen, Pin-Chu; Chen, Szu-Hao; Shen, Shih-Ming; Chen, Chien-Chih; Wang, Ching-Chiun; Chen, Chien-Tien

2011-12-01

Light sources with low color temperature (CT) are essential for their markedly less suppression effect on the secretion of melatonin, and high power efficiency is crucial for energy-saving. To provide visual comfort, the light source should also have a reasonably high color rendering index (CRI). In this report, we demonstrate the design and fabrication of low CT and high efficiency organic light-emitting diodes. The best resultant device exhibits a CT of 1,880 K, much lower than that of incandescent bulbs (2,000-2,500 K) and even as low as that of candles, (1,800-2,000 K), a beyond theoretical limit external quantum efficiency 22.7 %, and 36.0 lm/W at 100 cd/m 2. The high efficiency of the proposed device may be attributed to its interlayer, which helps effectively distribute the entering carriers into the available recombination zones.

FastQuery: A Parallel Indexing System for Scientific Data

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

Chou, Jerry; Wu, Kesheng; Prabhat,

2011-07-29

Modern scientific datasets present numerous data management and analysis challenges. State-of-the- art index and query technologies such as FastBit can significantly improve accesses to these datasets by augmenting the user data with indexes and other secondary information. However, a challenge is that the indexes assume the relational data model but the scientific data generally follows the array data model. To match the two data models, we design a generic mapping mechanism and implement an efficient input and output interface for reading and writing the data and their corresponding indexes. To take advantage of the emerging many-core architectures, we also developmore » a parallel strategy for indexing using threading technology. This approach complements our on-going MPI-based parallelization efforts. We demonstrate the flexibility of our software by applying it to two of the most commonly used scientific data formats, HDF5 and NetCDF. We present two case studies using data from a particle accelerator model and a global climate model. We also conducted a detailed performance study using these scientific datasets. The results show that FastQuery speeds up the query time by a factor of 2.5x to 50x, and it reduces the indexing time by a factor of 16 on 24 cores.« less

Rating health and stability of engineering structures via classification indexes of InSAR Persistent Scatterers

NASA Astrophysics Data System (ADS)

Pratesi, Fabio; Tapete, Deodato; Terenzi, Gloria; Del Ventisette, Chiara; Moretti, Sandro

2015-08-01

We propose a novel set of indexes to classify the information content of Persistent Scatterers (PS) and rate the health of engineering structures at urban to local scale. PS are automatically sampled and grouped via 'control areas' coinciding with the building and its surrounding environment. Density over the 'control areas' and velocity of PS are converted respectively into: Completeness of Information Index (Ici) that reflects the PS coverage grade; and Conservation Criticality Indexes (Icc) which rate the health condition of the monument separately for the object and surrounding control areas. The deformation pattern over the structure is classified as isolated (i) or diffused (d) based on the Velocity Distribution Index (Ivd). Both Ici and Icc are rated from A to E classes using a colour-coded system that intentionally emulates an energy-efficiency scale, to encourage the exploitation of PS by stakeholders and end-users in the practise of engineering surveying. Workability and reliability of the classification indexes are demonstrated over the urban heritage of Florence, Italy, using well established ERS-1/2 (1992-2000) descending, ENVISAT (2003-2010) ascending and descending PS datasets. The indexes are designed in perspective of handling outputs from InSAR processing of higher-resolution time series.

MICA: desktop software for comprehensive searching of DNA databases

PubMed Central

Stokes, William A; Glick, Benjamin S

2006-01-01

Background Molecular biologists work with DNA databases that often include entire genomes. A common requirement is to search a DNA database to find exact matches for a nondegenerate or partially degenerate query. The software programs available for such purposes are normally designed to run on remote servers, but an appealing alternative is to work with DNA databases stored on local computers. We describe a desktop software program termed MICA (K-Mer Indexing with Compact Arrays) that allows large DNA databases to be searched efficiently using very little memory. Results MICA rapidly indexes a DNA database. On a Macintosh G5 computer, the complete human genome could be indexed in about 5 minutes. The indexing algorithm recognizes all 15 characters of the DNA alphabet and fully captures the information in any DNA sequence, yet for a typical sequence of length L, the index occupies only about 2L bytes. The index can be searched to return a complete list of exact matches for a nondegenerate or partially degenerate query of any length. A typical search of a long DNA sequence involves reading only a small fraction of the index into memory. As a result, searches are fast even when the available RAM is limited. Conclusion MICA is suitable as a search engine for desktop DNA analysis software. PMID:17018144

Innovative Design and Performance Evaluation of Bionic Imprinting Toothed Wheel.

PubMed

Zhang, Zhihong; Wang, Xiaoyang; Tong, Jin; Stephen, Carr

2018-01-01

A highly efficient soil-burrowing dung beetle possesses an intricate outer contour curve on its foreleg end-tooth. This study was carried out based on evidence that this special outer contour curve has the potential of reducing soil penetration resistance and could enhance soil-burrowing efficiency. A toothed wheel is a typical agricultural implement for soil imprinting, to increase its working efficiency; the approach of the bionic geometrical structure was utilized to optimize the innovative shape of imprinting toothed wheel. Characteristics in the dung beetle's foreleg end-tooth were extracted and studied by the edge detection technique. Then, this special outer contour curve was modeled by a nine-order polynomial function and used for the innovative design of imprinting the tooth's cutting edge. Both the conventional and bionic teeth were manufactured, and traction tests in a soil bin were conducted. Taking required draft force and volume of imprinted microbasin as the evaluating indexes, operating efficiency and quality of different toothed wheels were compared and investigated. Results indicate that compared with the conventional toothed wheel, a bionic toothed wheel possesses a better forward resistance reduction property against soil and, meanwhile, can enhance the quality of soil imprinting by increasing the volume of the created micro-basin.

Novel design of inherently gain-flattened discrete highly nonlinear photonic crystal fiber Raman amplifier and dispersion compensation using a single pump in C-band.

PubMed

Varshney, Shailendra; Fujisawa, Takeshi; Saitoh, Kunimasa; Koshiba, Masanori

2005-11-14

In this paper, we report, for the first time, an inherently gain-flattened discrete highly nonlinear photonic crystal fiber (HNPCF) Raman amplifier (HNPCF-RA) design which shows 13.7 dB of net gain (with +/-0.85-dB gain ripple) over 28-nm bandwidth. The wavelength dependent leakage loss property of HNPCF is used to flatten the Raman gain of the amplifier module. The PCF structural design is based on W-shaped refractive index profile where the fiber parameters are well optimized by homely developed genetic algorithm optimization tool integrated with an efficient vectorial finite element method (V-FEM). The proposed fiber design has a high Raman gain efficiency of 4.88 W(-1) . km(-1) at a frequency shift of 13.1 THz, which is precisely evaluated through V-FEM. Additionally, the designed module, which shows ultra-wide single mode operation, has a slowly varying negative dispersion coefficient (-107.5 ps/nm/km at 1550 nm) over the operating range of wavelengths. Therefore, our proposed HNPCF-RA module acts as a composite amplifier with dispersion compensator functionality in a single component using a single pump.

Hierarchical Targeting Strategy for Enhanced Tumor Tissue Accumulation/Retention and Cellular Internalization.

PubMed

Wang, Sheng; Huang, Peng; Chen, Xiaoyuan

2016-09-01

Targeted delivery of therapeutic agents is an important way to improve the therapeutic index and reduce side effects. To design nanoparticles for targeted delivery, both enhanced tumor tissue accumulation/retention and enhanced cellular internalization should be considered simultaneously. So far, there have been very few nanoparticles with immutable structures that can achieve this goal efficiently. Hierarchical targeting, a novel targeting strategy based on stimuli responsiveness, shows good potential to enhance both tumor tissue accumulation/retention and cellular internalization. Here, the recent design and development of hierarchical targeting nanoplatforms, based on changeable particle sizes, switchable surface charges and activatable surface ligands, will be introduced. In general, the targeting moieties in these nanoplatforms are not activated during blood circulation for efficient tumor tissue accumulation, but re-activated by certain internal or external stimuli in the tumor microenvironment for enhanced cellular internalization. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A new approach on the upgrade of energetic system based on green energy. A complex comparative analysis of the EEDI and EEOI

NASA Astrophysics Data System (ADS)

Faitar, C.; Novac, I.

2016-08-01

In recent years, many environmental organizations was interested to optimize the energy consumption which has become, today, one of the main concerns to the whole world. From this point of view, the maritime industry, has strove to optimize the fuel consumption of ship through the development of engines and propulsion system, improve the hull design, or using alternative energies, this way making a reduction in the amount of CO2 released to the atmosphere. The main idea of this paper is to realize a complex comparative analysis of Energy Efficiency Design Index and Energy Efficiency Operational Indicator which are calculated in two cases: first, in a classical approach for a crude oil super tanker ship and second, after the energy performance of this ship has been improved by introducing alternative energy sources on board.

The Inverse Optimal Control Problem for a Three-Loop Missile Autopilot

NASA Astrophysics Data System (ADS)

Hwang, Donghyeok; Tahk, Min-Jea

2018-04-01

The performance characteristics of the autopilot must have a fast response to intercept a maneuvering target and reasonable robustness for system stability under the effect of un-modeled dynamics and noise. By the conventional approach, the three-loop autopilot design is handled by time constant, damping factor and open-loop crossover frequency to achieve the desired performance requirements. Note that the general optimal theory can be also used to obtain the same gain as obtained from the conventional approach. The key idea of using optimal control technique for feedback gain design revolves around appropriate selection and interpretation of the performance index for which the control is optimal. This paper derives an explicit expression, which relates the weight parameters appearing in the quadratic performance index to the design parameters such as open-loop crossover frequency, phase margin, damping factor, or time constant, etc. Since all set of selection of design parameters do not guarantee existence of optimal control law, explicit inequalities, which are named the optimality criteria for the three-loop autopilot (OC3L), are derived to find out all set of design parameters for which the control law is optimal. Finally, based on OC3L, an efficient gain selection procedure is developed, where time constant is set to design objective and open-loop crossover frequency and phase margin as design constraints. The effectiveness of the proposed technique is illustrated through numerical simulations.

Silicon nitride back-end optics for biosensor applications

NASA Astrophysics Data System (ADS)

Romero-García, Sebastian; Merget, Florian; Zhong, Frank C.; Finkelstein, Hod; Witzens, Jeremy

2013-05-01

Silicon nitride (SiN) is a promising candidate material for becoming a standard high-performance solution for integrated biophotonics applications in the visible spectrum. As a key feature, its compatibility with the complementary-oxidemetal- semiconductor (CMOS) technology permits cost reduction at large manufacturing volumes that is particularly advantageous for manufacturing consumables. In this work, we show that the back-end deposition of a thin SiN film enables the large light-cladding interaction desirable for biosensing applications while the refractive index contrast of the technology (Δn ≍ 0.5) also enables a considerable level of integration with reduced waveguide bend radii. Design and experimental validation also show that several advantages are derived from the moderate SiN/SiO2 refractive index contrast, such as lower scattering losses in interconnection waveguides and relaxed tolerances to fabrication imperfections as compared to higher refractive index contrast material systems. As a drawback, a moderate refractive index contrast also makes the implementation of compact grating couplers more challenging, due to the fact that only a relatively weak scattering strength can be achieved. Thereby, the beam diffracted by the grating tends to be rather large and consequently exhibit stringent angular alignment tolerances. Here, we experimentally demonstrate how a proper design of the bottom and top cladding oxide thicknesses allows reduction of the full-width at half maximum (FWHM) and alleviates this problem. Additionally, the inclusion of a CMOS-compatible AlCu/TiN bottom reflector further decreases the FWHM and increases the coupling efficiency. Finally, we show that focusing grating designs greatly reduce the device footprint without penalizing the device metrics.

Designing for Peta-Scale in the LSST Database

NASA Astrophysics Data System (ADS)

Kantor, J.; Axelrod, T.; Becla, J.; Cook, K.; Nikolaev, S.; Gray, J.; Plante, R.; Nieto-Santisteban, M.; Szalay, A.; Thakar, A.

2007-10-01

The Large Synoptic Survey Telescope (LSST), a proposed ground-based 8.4 m telescope with a 10 deg^2 field of view, will generate 15 TB of raw images every observing night. When calibration and processed data are added, the image archive, catalogs, and meta-data will grow 15 PB yr^{-1} on average. The LSST Data Management System (DMS) must capture, process, store, index, replicate, and provide open access to this data. Alerts must be triggered within 30 s of data acquisition. To do this in real-time at these data volumes will require advances in data management, database, and file system techniques. This paper describes the design of the LSST DMS and emphasizes features for peta-scale data. The LSST DMS will employ a combination of distributed database and file systems, with schema, partitioning, and indexing oriented for parallel operations. Image files are stored in a distributed file system with references to, and meta-data from, each file stored in the databases. The schema design supports pipeline processing, rapid ingest, and efficient query. Vertical partitioning reduces disk input/output requirements, horizontal partitioning allows parallel data access using arrays of servers and disks. Indexing is extensive, utilizing both conventional RAM-resident indexes and column-narrow, row-deep tag tables/covering indices that are extracted from tables that contain many more attributes. The DMS Data Access Framework is encapsulated in a middleware framework to provide a uniform service interface to all framework capabilities. This framework will provide the automated work-flow, replication, and data analysis capabilities necessary to make data processing and data quality analysis feasible at this scale.

What is greener than a VMT tax? The case for an indexed energy user fee to finance us surface transportation

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

Greene, David L

Highway finance in the United States is perceived by many to be in a state of crisis, primarily due to the erosion of motor fuel tax revenues due to inflation, fuel economy improvement, increased use of alternative sources of energy and diversion of revenues to other purposes. Monitoring vehicle miles of travel (VMT) and charging highway users per mile has been proposed as a replacement for the motor fuel tax. A VMT user fee, however, does not encourage energy efficiency in vehicle design, purchase and operation, as would a user fee levied on all forms of commercial energy used formore » transportation and indexed to the average efficiency of vehicles on the road and to inflation. An indexed roadway user toll on energy (IRoUTE) would induce two to four times as much reduction in greenhouse gas (GHG) emissions and petroleum use as a pure VMT user fee. However, it is not a substitute for pricing GHG emissions and would make only a small but useful contribution to reducing petroleum dependence. An indexed energy user fee cannot adequately address the problems of traffic congestion and heavy vehicle cost responsibility. It could, however, be a key component of a comprehensive system of financing surface transportation that would eventually also include time and place specific monitoring of VMT for congestion pricing, externality charges and heavy vehicle user fees.« less

[Criteria of estimation of state forensic-medical expert activity administration].

PubMed

Klevno, V A; Loban, I E

2008-01-01

Criteria of estimation of state forensic medical activity administration were systematized and their content was considered. New integral index of administration efficiency - index of technological efficiency - was developed and proved.

Natural language information retrieval in digital libraries

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

Strzalkowski, T.; Perez-Carballo, J.; Marinescu, M.

In this paper we report on some recent developments in joint NYU and GE natural language information retrieval system. The main characteristic of this system is the use of advanced natural language processing to enhance the effectiveness of term-based document retrieval. The system is designed around a traditional statistical backbone consisting of the indexer module, which builds inverted index files from pre-processed documents, and a retrieval engine which searches and ranks the documents in response to user queries. Natural language processing is used to (1) preprocess the documents in order to extract content-carrying terms, (2) discover inter-term dependencies and buildmore » a conceptual hierarchy specific to the database domain, and (3) process user`s natural language requests into effective search queries. This system has been used in NIST-sponsored Text Retrieval Conferences (TREC), where we worked with approximately 3.3 GBytes of text articles including material from the Wall Street Journal, the Associated Press newswire, the Federal Register, Ziff Communications`s Computer Library, Department of Energy abstracts, U.S. Patents and the San Jose Mercury News, totaling more than 500 million words of English. The system have been designed to facilitate its scalability to deal with ever increasing amounts of data. In particular, a randomized index-splitting mechanism has been installed which allows the system to create a number of smaller indexes that can be independently and efficiently searched.« less

GSHR-Tree: a spatial index tree based on dynamic spatial slot and hash table in grid environments

NASA Astrophysics Data System (ADS)

Chen, Zhanlong; Wu, Xin-cai; Wu, Liang

2008-12-01

Computation Grids enable the coordinated sharing of large-scale distributed heterogeneous computing resources that can be used to solve computationally intensive problems in science, engineering, and commerce. Grid spatial applications are made possible by high-speed networks and a new generation of Grid middleware that resides between networks and traditional GIS applications. The integration of the multi-sources and heterogeneous spatial information and the management of the distributed spatial resources and the sharing and cooperative of the spatial data and Grid services are the key problems to resolve in the development of the Grid GIS. The performance of the spatial index mechanism is the key technology of the Grid GIS and spatial database affects the holistic performance of the GIS in Grid Environments. In order to improve the efficiency of parallel processing of a spatial mass data under the distributed parallel computing grid environment, this paper presents a new grid slot hash parallel spatial index GSHR-Tree structure established in the parallel spatial indexing mechanism. Based on the hash table and dynamic spatial slot, this paper has improved the structure of the classical parallel R tree index. The GSHR-Tree index makes full use of the good qualities of R-Tree and hash data structure. This paper has constructed a new parallel spatial index that can meet the needs of parallel grid computing about the magnanimous spatial data in the distributed network. This arithmetic splits space in to multi-slots by multiplying and reverting and maps these slots to sites in distributed and parallel system. Each sites constructs the spatial objects in its spatial slot into an R tree. On the basis of this tree structure, the index data was distributed among multiple nodes in the grid networks by using large node R-tree method. The unbalance during process can be quickly adjusted by means of a dynamical adjusting algorithm. This tree structure has considered the distributed operation, reduplication operation transfer operation of spatial index in the grid environment. The design of GSHR-Tree has ensured the performance of the load balance in the parallel computation. This tree structure is fit for the parallel process of the spatial information in the distributed network environments. Instead of spatial object's recursive comparison where original R tree has been used, the algorithm builds the spatial index by applying binary code operation in which computer runs more efficiently, and extended dynamic hash code for bit comparison. In GSHR-Tree, a new server is assigned to the network whenever a split of a full node is required. We describe a more flexible allocation protocol which copes with a temporary shortage of storage resources. It uses a distributed balanced binary spatial tree that scales with insertions to potentially any number of storage servers through splits of the overloaded ones. The application manipulates the GSHR-Tree structure from a node in the grid environment. The node addresses the tree through its image that the splits can make outdated. This may generate addressing errors, solved by the forwarding among the servers. In this paper, a spatial index data distribution algorithm that limits the number of servers has been proposed. We improve the storage utilization at the cost of additional messages. The structure of GSHR-Tree is believed that the scheme of this grid spatial index should fit the needs of new applications using endlessly larger sets of spatial data. Our proposal constitutes a flexible storage allocation method for a distributed spatial index. The insertion policy can be tuned dynamically to cope with periods of storage shortage. In such cases storage balancing should be favored for better space utilization, at the price of extra message exchanges between servers. This structure makes a compromise in the updating of the duplicated index and the transformation of the spatial index data. Meeting the needs of the grid computing, GSHRTree has a flexible structure in order to satisfy new needs in the future. The GSHR-Tree provides the R-tree capabilities for large spatial datasets stored over interconnected servers. The analysis, including the experiments, confirmed the efficiency of our design choices. The scheme should fit the needs of new applications of spatial data, using endlessly larger datasets. Using the system response time of the parallel processing of spatial scope query algorithm as the performance evaluation factor, According to the result of the simulated the experiments, GSHR-Tree is performed to prove the reasonable design and the high performance of the indexing structure that the paper presented.

New designs and characterization techniques for thin-film solar cells

NASA Astrophysics Data System (ADS)

Pang, Yutong

This thesis presents a fundamentally new thin-film photovoltaic design and develops several novel characterization techniques that improve the accuracy of thin-film solar cell computational models by improving the accuracy of the input data. We first demonstrate a novel organic photovoltaic (OPV) design, termed a "Slot OPV", in which the active layer is less than 50 nm; We apply the principles of slot waveguides to confine light within the active layer. According to our calculation, the guided-mode absorption for a 10nm thick active layer equal to the absorption of normal incidence on an OPV with a 100nm thick active layer. These results, together with the expected improvement in charge extraction for ultrathin layers, suggest that slot OPVs can be designed with greater power conversion efficiency than today's state-of-art OPV architectures if practical challenges, such as the efficient coupling of light into these modes, can be overcome. The charge collection probability, i.e. the probability that charges generated by absorption of a photon are successfully collected as current, is a critical feature for all kinds of solar cells. While the electron-beam-induced current (EBIC) method has been used in the past to successfully reconstruct the charge collection probability, this approach is destructive and requires time-consuming sample preparation. We demonstrate a new nondestructive optoelectronic method to reconstruct the charge collection probability by analyzing the internal quantum efficiency (IQE) data that are measured on copper indium gallium diselenide (CIGS) thin-film solar cells. We further improve the method with a parameter-independent regularization approach. Then we introduce the Self-Constrained Ill-Posed Inverse Problem (SCIIP) method, which improves the signal-to-noise of the solution by using the regularization method with system constraints and optimization via an evolutionary algorithm. For a thin-film solar cell optical model to be an accurate representation of reality, the measured refractive index profile of the solar cell used as input to the model must also be accurate. We describe a new method for reconstructing the depth-dependent refractive-index profile with high spatial resolution in thin photoactive layers. This novel technique applies to any thin film, including the photoactive layers of a broad range of thin-film photovoltaics. Together, these methods help us improve the measurement accuracy of the depth profile within thin-film photovoltaics for optical and electronic properties such as refractive index and charge collection probability, which is critical to the understanding, modeling, and optimization of these devices.

[Influence of contractual medical association on inpatient service performance].

PubMed

Wu, Zhi-jun; Jian, Wei-yan

2015-06-18

To study the influence of contractual medical association on inpatient service performance. The data came from "Database of Inpatient Record" administered by Department of Medical Insurance. Using diagnosis related groups (DRG) as the tool of risk-adjustment, the third-tier general hospitals and second-tier general hospitals in medical alliance as the intervention group, and the average level of the same grade local hospitals as the control group, the influence of medical alliance on inpatient service performance was evaluated. The difference in difference (DID) method was used for the data analysis. The assessing indicators included the number of DRG group, case mix index (CMI), the total weight, cost efficiency index and time efficiency index. After the establishment of medical association, compared with the average level of the same grade local hospitals, in the third-tier general hospitals of medical alliance, the growth rate of the total weight had declined, and cost efficiency index had increased, while in the second-tier general hospitals of medical alliance, the CMI value had declined, and the cost efficiency index had increased. Contractual medical association played a role of triage patients, and improved the service levels and management efficiency of the second-tier general hospitals.

The evaluation of basin water resources utilization efficiency based on Chaos projection mode

NASA Astrophysics Data System (ADS)

Guan, X.; Liang, S.; Meng, Y.; Wang, H.

2017-12-01

To promote the coordinated development of a healthy economy, society, and environment, and the sustainable development of water resources comprehensive utilization efficiency (WRCUE), this study investigated appropriate indicators using the trapezoidal fuzzy number method, and constructed an evaluation index system for WRCUE. A WRCUE evaluation model is applied to the areas in the Yellow River Basin in China using a genetic projection pursuit method. The comprehensive evaluation index system of water use efficiency includes 6 indicators: Water consumption per unit industrial value added, water consumption per unit GDP, eliminate the climate effect on agricultural water use efficiency, irrigation water consumption per unit area, domestic water use per capita and industrial water ratio. Then, multiple indexes in the index system are transformed to a comprehensive index by the combined model, which is used to represent the total water resources utilization efficiency. Results show that the WRCUE in Yellow River basin and the provinces have a great distance. WRCUE is well developed in Shanxi, Shandong, and Henan provinces, moderately developed in Shaanxi, Inner Mongolia, and Sichuan provinces, and poorly developed in the Ningxia Autonomous Region, Gansu Province, and Qinghai Province. According to the capacities of provinces, related measures are proposed.

Role of the electron blocking layer in the graded-index separate confinement heterostructure nitride laser diodes

NASA Astrophysics Data System (ADS)

Bojarska, Agata; Goss, Jakub; Stanczyk, Szymon; Makarowa, Irina; Schiavon, Dario; Czernecki, Robert; Suski, Tadeusz; Perlin, Piotr

2018-04-01

In this work, we investigate the role of the electron blocking layer (EBL) in laser diodes based on a graded index separate confinement heterostructure. We compare two sets of devices with very different EBL aluminum composition (3% and 12%) and design (graded and superlattice). The results of electro-optical characterization of these laser diodes reveal surprisingly modest role of electron blocking layer composition in determination of the threshold current and the differential efficiency values. However, EBL structure influences the operating voltage, which is decreased for devices with lower EBL and superlattice EBL. We observe also the differences in the thermal stability of devices - characteristic temperature is lower for lasers with 3% Al in EBL.

Hybrid unidirectional meta-coupler for vertical incidence to a high-refractive-index waveguide in telecom wavelength.

PubMed

Gong, Chensheng; Zhang, Jianhao; He, Sailing

2017-12-15

Unidirectional optical manipulation, especially the coupling from a vertical light beam to a waveguide unidirectionally, is desirable in photonic integration. We first propose a hybrid unidirectional meta-coupler for vertical incidence to a high-refractive-index waveguide in telecom wavelength, a periodic plasmonic metasurface composed of metal-insulator-metal unit cells is used for phase matching. Three designs are given for devices working around wavelengths 0.85, 1.31, and 1.55 μm. The simulated coupling efficiencies are all around 70%, and the 1 dB coupling bandwidths are 29, 82, and 105 nm, respectively. Our approach paves the way for the applications of optical metasurfaces to planar lightwave circuits.

Dual functional star polymers for lubricants

DOE PAGES

Cosimbescu, Lelia; Robinson, Joshua W.; Zhou, Yan; ...

2016-09-12

Star-shaped poly(alkyl methacrylate)s (PAMAs) with a three arm architecturewere designed, prepared and their performance as a dual additive (viscosity index improver and friction modifier) for engine oils was evaluated. Furthermore, the structure property relationships between the macromolecular structure and lubricant performance were studied, such as molecular weight and polarity effects on the viscosity index. Several copolymers of dodecylmethacrylate with polar methacrylates in various amounts and various topologies, were synthesized as model compounds. Star polymers with a polar content of at least 10% in a block or tapered block topology effectively reduced the friction coefficient in both mixed and boundary lubricationmore » regimes. Furthermore, a polar content of 20% was efficient in reducing friction in both random and block topologies.« less

Effect of water stress on total biomass, tuber yield, harvest index and water use efficiency in Jerusalem artichoke

USDA-ARS?s Scientific Manuscript database

The objectives of this study were to determine the effect of drought on tuber yield, total biomass, harvest index, water use efficiency of tuber yield (WUEt) and water use efficiency of biomass (WUEb), and to evaluate the differential responses of Jerusalem artichoke (JA) varieties under drought str...

Methods for slow axis beam quality improvement of high power broad area diode lasers

NASA Astrophysics Data System (ADS)

An, Haiyan; Xiong, Yihan; Jiang, Ching-Long J.; Schmidt, Berthold; Treusch, Georg

2014-03-01

For high brightness direct diode laser systems, it is of fundamental importance to improve the slow axis beam quality of the incorporated laser diodes regardless what beam combining technology is applied. To further advance our products in terms of increased brightness at a high power level, we must optimize the slow axis beam quality despite the far field blooming at high current levels. The later is caused predominantly by the built-in index step in combination with the thermal lens effect. Most of the methods for beam quality improvements reported in publications sacrifice the device efficiency and reliable output power. In order to improve the beam quality as well as maintain the efficiency and reliable output power, we investigated methods of influencing local heat generation to reduce the thermal gradient across the slow axis direction, optimizing the built-in index step and discriminating high order modes. Based on our findings, we have combined different methods in our new device design. Subsequently, the beam parameter product (BPP) of a 10% fill factor bar has improved by approximately 30% at 7 W/emitter without efficiency penalty. This technology has enabled fiber coupled high brightness multi-kilowatt direct diode laser systems. In this paper, we will elaborate on the methods used as well as the results achieved.

Basic aspects and contributions to the optimization of energy systems exploitation of a super tanker ship

NASA Astrophysics Data System (ADS)

Faitar, C.; Novac, I.

2017-08-01

Today, the concept of energy efficiency or energy optimization in ships has become one of the main problems of engineers in the whole world. To increase the fiability of a crude oil super tanker ship it means, among other things, to improve the energy performance and optimize the fuel consumption of ship through the development of engines and propulsion system or using alternative energies. Also, the importance of having an effective and reliable Power Management System (PMS) in a vessel operating system means to reduce operational costs and maintain power system of machine parts working in minimum stress in all operating conditions. Studying the Energy Efficiency Design Index and Energy Efficiency Operational Indicator for a crude oil super tanker ship, it allows us to study the reconfiguration of ship power system introducing new generation systems.

Damage tolerance and structural monitoring for wind turbine blades.

PubMed

McGugan, M; Pereira, G; Sørensen, B F; Toftegaard, H; Branner, K

2015-02-28

The paper proposes a methodology for reliable design and maintenance of wind turbine rotor blades using a condition monitoring approach and a damage tolerance index coupling the material and structure. By improving the understanding of material properties that control damage propagation it will be possible to combine damage tolerant structural design, monitoring systems, inspection techniques and modelling to manage the life cycle of the structures. This will allow an efficient operation of the wind turbine in terms of load alleviation, limited maintenance and repair leading to a more effective exploitation of offshore wind. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

An evaluation of alternative selection indexes for a non-linear profit trait approaching its economic optimum.

PubMed

Martin-Collado, D; Byrne, T J; Visser, B; Amer, P R

2016-12-01

This study used simulation to evaluate the performance of alternative selection index configurations in the context of a breeding programme where a trait with a non-linear economic value is approaching an economic optimum. The simulation used a simple population structure that approximately mimics selection in dual purpose sheep flocks in New Zealand (NZ). In the NZ dual purpose sheep population, number of lambs born is a genetic trait that is approaching an economic optimum, while genetically correlated growth traits have linear economic values and are not approaching any optimum. The predominant view among theoretical livestock geneticists is that the optimal approach to select for nonlinear profit traits is to use a linear selection index and to update it regularly. However, there are some nonlinear index approaches that have not been evaluated. This study assessed the efficiency of the following four alternative selection index approaches in terms of genetic progress relative to each other: (i) a linear index, (ii) a linear index updated regularly, (iii) a nonlinear (quadratic) index, and (iv) a NLF index (nonlinear index below the optimum and then flat). The NLF approach does not reward or penalize animals for additional genetic merit beyond the trait optimum. It was found to be at least comparable in efficiency to the approach of regularly updating the linear index with short (15 year) and long (30 year) time frames. The relative efficiency of this approach was slightly reduced when the current average value of the nonlinear trait was close to the optimum. Finally, practical issues of industry application of indexes are considered and some potential practical benefits of efficient deployment of a NLF index in highly heterogeneous industries (breeds, flocks and production environments) such as in the NZ dual purpose sheep population are discussed. © 2016 Blackwell Verlag GmbH.

Enhanced performance of an S-band fiber laser using a thulium-doped photonic crystal fiber

NASA Astrophysics Data System (ADS)

Muhammad, A. R.; Emami, S. D.; Hmood, J. K.; Sayar, K.; Penny, R.; Abdul-Rashid, H. A.; Ahmad, H.; Harun, S. W.

2014-11-01

This work proposes a new method to enhance the performance of an S-band fiber laser by using a thulium-doped photonic crystal fiber (PCF). The proposed method is based on amplified spontaneous emission (ASE) suppression provided by the thulium-doped PCF unique geometric structure. The enhanced performance of this filter based PCF is dependent on the short and long cut-off wavelength characteristics that define the fiber transmission window. Realizing the short wavelength cut-off location requires the PCF cladding to be doped with a high index material, which provides a refractive index difference between the core and cladding region. Achieving the long cut-off wavelength necessitates enlarging the size of the air holes surrounding the rare-earth doped core region. The PCF structure is optimized so as to achieve the desired ASE suppression regions of below 0.8 μm and above 1.8 μm. The laser performance is simulated for different host media, namely pure silica, alumino-silicate, and fluoride-based fiber ZBLAN based on this thulium-doped PCF design. The host media spectroscopic details, including lifetime variations and quantum efficiency effect on the lasing emission are also discussed. Information on the filter based PCF design is gathered via a full-vectorial finite element method analysis and specifically a numerical modelling solution for the energy level rate equation using the Runge-Kutta method. Results are analyzed for gain improvement, lasing cavity, laser efficiency and effect of core size diameter variation. Results are compared with conventional thulium-doped fiber and thulium-doped PCF for every single host media. We observe that the ZBLAN host media is the most promising candidate due to its greater quantum efficiency.

Design of ultra-compact composite plasmonic Mach-Zehnder interferometer for chemical vapor sensing

NASA Astrophysics Data System (ADS)

Ghosh, Souvik; Rahman, B. M. A.

2018-02-01

Following the Industrial advancements in the last few decades, highly flammable chemicals, such as ethanol (CH3CH2OH) and methanol (CH3OH) are widely being used in daily life. Ethanol have some degrees of carcinogenic effects in human whereas acute and chronic exposer of methanol results blurred vision and nausea. Therefore, accurate and efficient sensing of these two vapors in industrial environment are of high priorities. We have designed a novel, ultra-compact chemical vapor sensor based on composite plasmonic horizontal slot waveguide (CPHSW) where a low-index porous-ZnO (P-ZnO) layer is sandwiched in between top silver metal and lower silicon layers. Different P-ZnO templates, such as nano-spheres, nano-sheets and nanoplates could be used for high-selectivity of ethanol and methanol at different temperatures. The Lorentz-Lorenz model is used to determine the variation of P-ZnO refractive index (RI) with porosity and equivalent RI of P-ZnO layer for capillary condensation of different percentage of absorbed vapor. An in-house, new divergence modified finite element method is used to calculate effective index and attenuation sensitivity. Plasmonic modal analyses of dominant quasi-TM mode shows a high 42% power confinement in the slot. Next, an ultra-compact MZI incorporating a few micrometres long CPHSW is designed and analysed as a transducer device for accurate detection of effective index change. The device performance has been studied for different percentage of ethanol into P-ZnO with different porosity and a maximum phase sensitivity of >0.35 a.u. is achieved for both the chemical vapors at a mid-IR operating wavelength of 1550 nm.

Identification of high-efficiency 3'GG gRNA motifs in indexed FASTA files with ngg2.

PubMed

Roberson, Elisha D O

CRISPR/Cas9 is emerging as one of the most-used methods of genome modification in organisms ranging from bacteria to human cells. However, the efficiency of editing varies tremendously site-to-site. A recent report identified a novel motif, called the 3'GG motif, which substantially increases the efficiency of editing at all sites tested in C. elegans . Furthermore, they highlighted that previously published gRNAs with high editing efficiency also had this motif. I designed a python command-line tool, ngg2, to identify 3'GG gRNA sites from indexed FASTA files. As a proof-of-concept, I screened for these motifs in six model genomes: Saccharomyces cerevisiae , Caenorhabditis elegans , Drosophila melanogaster , Danio rerio , Mus musculus , and Homo sapiens. I also scanned the genomes of pig ( Sus scrofa ) and African elephant ( Loxodonta africana ) to demonstrate the utility in non-model organisms. I identified more than 60 million single match 3'GG motifs in these genomes. Greater than 61% of all protein coding genes in the reference genomes had at least one unique 3'GG gRNA site overlapping an exon. In particular, more than 96% of mouse and 93% of human protein coding genes have at least one unique, overlapping 3'GG gRNA. These identified sites can be used as a starting point in gRNA selection, and the ngg2 tool provides an important ability to identify 3'GG editing sites in any species with an available genome sequence.

Innovative Design and Performance Evaluation of Bionic Imprinting Toothed Wheel

PubMed Central

Wang, Xiaoyang; Tong, Jin; Stephen, Carr

2018-01-01

A highly efficient soil-burrowing dung beetle possesses an intricate outer contour curve on its foreleg end-tooth. This study was carried out based on evidence that this special outer contour curve has the potential of reducing soil penetration resistance and could enhance soil-burrowing efficiency. A toothed wheel is a typical agricultural implement for soil imprinting, to increase its working efficiency; the approach of the bionic geometrical structure was utilized to optimize the innovative shape of imprinting toothed wheel. Characteristics in the dung beetle's foreleg end-tooth were extracted and studied by the edge detection technique. Then, this special outer contour curve was modeled by a nine-order polynomial function and used for the innovative design of imprinting the tooth's cutting edge. Both the conventional and bionic teeth were manufactured, and traction tests in a soil bin were conducted. Taking required draft force and volume of imprinted microbasin as the evaluating indexes, operating efficiency and quality of different toothed wheels were compared and investigated. Results indicate that compared with the conventional toothed wheel, a bionic toothed wheel possesses a better forward resistance reduction property against soil and, meanwhile, can enhance the quality of soil imprinting by increasing the volume of the created micro-basin. PMID:29515651

Effect of increasing energy cost on arm coordination in elite sprint swimmers.

PubMed

Komar, J; Leprêtre, P M; Alberty, M; Vantorre, J; Fernandes, R J; Hellard, P; Chollet, D; Seifert, L

2012-06-01

The purpose of this study was to analyze the changes in stroke parameters, motor organization and swimming efficiency with increasing energy cost in aquatic locomotion. Seven elite sprint swimmers performed a 6×300-m incremental swimming test. Stroke parameters (speed, stroke rate and stroke length), motor organization (arm stroke phases and arm coordination index), swimming efficiency (swimming speed squared and hand speed squared) and stroke index were calculated from aerial and underwater side-view cameras. The energy cost of locomotion was assessed by measuring oxygen consumption and blood lactate. Results showed that the increase in energy cost of locomotion was correlated to an increase in the index of coordination and stroke rate, and a decrease in stroke length (p<.05). Furthermore, indicators of swimming efficiency and stroke index did not change significantly with the speed increments (p<.05), indicating that swimmers did not decrease their efficiency despite the increase in energy cost. In parallel, an increase in the index of coordination IdC and stroke rate were observed, along with a decrease in stroke length, stroke index and hand speed squared with each increment, revealing an adaptation to the fatigue within the 300m. Copyright © 2011 Elsevier B.V. All rights reserved.

Novel aplanatic designs for LED concentration

NASA Astrophysics Data System (ADS)

Ricketts, Melissa; Winston, Roland; Jiang, Lun

2014-09-01

Aplanats make great concentrators because of their near perfect imaging. Aplanatic conditions can be satisfied using two surface curves (generally mirrored surfaces) in two dimensions (see Figure 1) which are constructed by successive approximation to create a highly efficient concentrator for both concentration and illumination. For concentration purposes, having a two mirror system would be impossible because the front mirror would block incoming light (see figure 2) so the idea is to replace the front mirror with a "one-way" mirror. Light from a lower index can be transmitted, so if the aplanat surface is a higher index light is allowed to enter, and be trapped. In the Jellyfish design, TIR takes place except for light striking the surface within the range of critical angles. To combat that, a small area of reflective coating is applied to the central top part of the Jellyfish, where TIR fails (In the middle) to keep the light there from directly escaping (see figure 3). The design works in both forwards and reverse. Light entering can be focused to a collecter, or the collecter can be replaced with a light source to concentrate light out. In this case, LEDs are used for their highly efficienct properties.

Quasi-experimental study designs series-paper 8: identifying quasi-experimental studies to inform systematic reviews.

PubMed

Glanville, Julie; Eyers, John; Jones, Andrew M; Shemilt, Ian; Wang, Grace; Johansen, Marit; Fiander, Michelle; Rothstein, Hannah

2017-09-01

This article reviews the available evidence and guidance on methods to identify reports of quasi-experimental (QE) studies to inform systematic reviews of health care, public health, international development, education, crime and justice, and social welfare. Research, guidance, and examples of search strategies were identified by searching a range of databases, key guidance documents, selected reviews, conference proceedings, and personal communication. Current practice and research evidence were summarized. Four thousand nine hundred twenty-four records were retrieved by database searches, and additional documents were obtained by other searches. QE studies are challenging to identify efficiently because they have no standardized nomenclature and may be indexed in various ways. Reliable search filters are not available. There is a lack of specific resources devoted to collecting QE studies and little evidence on where best to search. Searches to identify QE studies should search a range of resources and, until indexing improves, use strategies that focus on the topic rather than the study design. Better definitions, better indexing in databases, prospective registers, and reporting guidance are required to improve the retrieval of QE studies and promote systematic reviews of what works based on the evidence from such studies. Copyright © 2017 Elsevier Inc. All rights reserved.

Eco-efficiency Analysis of Furniture Product Using Life Cycle Assessment

NASA Astrophysics Data System (ADS)

Rinawati, Dyah Ika; Sriyanto; Sari, Diana Puspita; Prayodha, Andana Cantya

2018-02-01

Furniture is one of Indonesia's main commodities strategically role in economic growth and employment in Indonesia. In their production process there many wastes resulted, such as such as sawdust, cuttings - pieces of wood, components that do not conform to specifications and the edges of wood from a log. Contrast with requirement of timber for furniture industries, availability of raw material sources decrease because of limited forest areas. Beside that, using electricity and chemical material in furniture production process have impact to environment. This study aim to assess the eco-cost and eco-efficiency ratio of the product so strategic recommendations to improve the eco-efficiency of products can be designed. The results of data processing showed the environmental costs of the furniture production process amount Rp 30.887.84. Eco-efficiency index of furniture products studied was 4,79 with the eco-efficiency ratio of 79,12%. This result means that the measured furniture products already profitable and sustainable, as well as its production process is already fairly efficient. However, improved performance of the production process can still be done to improve the eco-efficiency by minimizing the use of raw materials.

Providing R-Tree Support for Mongodb

NASA Astrophysics Data System (ADS)

Xiang, Longgang; Shao, Xiaotian; Wang, Dehao

2016-06-01

Supporting large amounts of spatial data is a significant characteristic of modern databases. However, unlike some mature relational databases, such as Oracle and PostgreSQL, most of current burgeoning NoSQL databases are not well designed for storing geospatial data, which is becoming increasingly important in various fields. In this paper, we propose a novel method to provide R-tree index, as well as corresponding spatial range query and nearest neighbour query functions, for MongoDB, one of the most prevalent NoSQL databases. First, after in-depth analysis of MongoDB's features, we devise an efficient tabular document structure which flattens R-tree index into MongoDB collections. Further, relevant mechanisms of R-tree operations are issued, and then we discuss in detail how to integrate R-tree into MongoDB. Finally, we present the experimental results which show that our proposed method out-performs the built-in spatial index of MongoDB. Our research will greatly facilitate big data management issues with MongoDB in a variety of geospatial information applications.

A Spatiotemporal Indexing Approach for Efficient Processing of Big Array-Based Climate Data with MapReduce

NASA Technical Reports Server (NTRS)

Li, Zhenlong; Hu, Fei; Schnase, John L.; Duffy, Daniel Q.; Lee, Tsengdar; Bowen, Michael K.; Yang, Chaowei

2016-01-01

Climate observations and model simulations are producing vast amounts of array-based spatiotemporal data. Efficient processing of these data is essential for assessing global challenges such as climate change, natural disasters, and diseases. This is challenging not only because of the large data volume, but also because of the intrinsic high-dimensional nature of geoscience data. To tackle this challenge, we propose a spatiotemporal indexing approach to efficiently manage and process big climate data with MapReduce in a highly scalable environment. Using this approach, big climate data are directly stored in a Hadoop Distributed File System in its original, native file format. A spatiotemporal index is built to bridge the logical array-based data model and the physical data layout, which enables fast data retrieval when performing spatiotemporal queries. Based on the index, a data-partitioning algorithm is applied to enable MapReduce to achieve high data locality, as well as balancing the workload. The proposed indexing approach is evaluated using the National Aeronautics and Space Administration (NASA) Modern-Era Retrospective Analysis for Research and Applications (MERRA) climate reanalysis dataset. The experimental results show that the index can significantly accelerate querying and processing (10 speedup compared to the baseline test using the same computing cluster), while keeping the index-to-data ratio small (0.0328). The applicability of the indexing approach is demonstrated by a climate anomaly detection deployed on a NASA Hadoop cluster. This approach is also able to support efficient processing of general array-based spatiotemporal data in various geoscience domains without special configuration on a Hadoop cluster.

ADP and brucellosis indemnity systems development

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

Sanders, W.M.; Harlan, B.L.

1976-01-01

Our initial study of the USDA/TAHC Brucellosis Indemnity Program in Texas has shown that both the efficiency and rate of claim payments can be increased by the application of present day computer technologies. Two main factors contribute to these increases: the number of discrepancies that are caused by poor penmanship, transposition of numbers, and other human errors can be monitored and minimized; and the documented information can be indexed, sorted, and searched faster, more efficiently, and without human error. The overall flow of documentation that is used to control the movement of infected or exposed animals through commerce should bemore » studied. A new system should be designed that fully utilizes present day computer and electronic technologies.« less

Development of noSQL data storage for the ATLAS PanDA Monitoring System

NASA Astrophysics Data System (ADS)

Potekhin, M.; ATLAS Collaboration

2012-06-01

For several years the PanDA Workload Management System has been the basis for distributed production and analysis for the ATLAS experiment at the LHC. Since the start of data taking PanDA usage has ramped up steadily, typically exceeding 500k completed jobs/day by June 2011. The associated monitoring data volume has been rising as well, to levels that present a new set of challenges in the areas of database scalability and monitoring system performance and efficiency. These challenges are being met with a R&D effort aimed at implementing a scalable and efficient monitoring data storage based on a noSQL solution (Cassandra). We present our motivations for using this technology, as well as data design and the techniques used for efficient indexing of the data. We also discuss the hardware requirements as they were determined by testing with actual data and realistic loads.

Efficient Second-Harmonic Generation in Nanocrystalline Silicon Nanoparticles.

PubMed

Makarov, Sergey V; Petrov, Mihail I; Zywietz, Urs; Milichko, Valentin; Zuev, Dmitry; Lopanitsyna, Natalia; Kuksin, Alexey; Mukhin, Ivan; Zograf, George; Ubyivovk, Evgeniy; Smirnova, Daria A; Starikov, Sergey; Chichkov, Boris N; Kivshar, Yuri S

2017-05-10

Recent trends to employ high-index dielectric particles in nanophotonics are motivated by their reduced dissipative losses and large resonant enhancement of nonlinear effects at the nanoscale. Because silicon is a centrosymmetric material, the studies of nonlinear optical properties of silicon nanoparticles have been targeting primarily the third-harmonic generation effects. Here we demonstrate, both experimentally and theoretically, that resonantly excited nanocrystalline silicon nanoparticles fabricated by an optimized laser printing technique can exhibit strong second-harmonic generation (SHG) effects. We attribute an unexpectedly high yield of the nonlinear conversion to a nanocrystalline structure of nanoparticles supporting the Mie resonances. The demonstrated efficient SHG at green light from a single silicon nanoparticle is 2 orders of magnitude higher than that from unstructured silicon films. This efficiency is significantly higher than that of many plasmonic nanostructures and small silicon nanoparticles in the visible range, and it can be useful for a design of nonlinear nanoantennas and silicon-based integrated light sources.

Low-loss and energy efficient modulation in silicon photonic waveguides by adiabatic elimination scheme

NASA Astrophysics Data System (ADS)

Mrejen, Michael; Suchowski, Haim; Bachelard, Nicolas; Wang, Yuan; Zhang, Xiang

2017-07-01

High-speed Silicon Photonics calls for solutions providing a small footprint, high density, and minimum crosstalk, as exemplified by the recent development of integrated optical modulators. Yet, the performances of such modulators are hindered by intrinsic material losses, which results in low energy efficiency. Using the concept of Adiabatic Elimination, here, we introduce a scheme allowing for the low-loss modulation in densely packed waveguides. Our system is composed of two waveguides, whose coupling is mediated by an intermediate third waveguide. The signal is carried by the two outer modes, while the active control of their coupling is achieved via the intermediate dark mode. The modulation is performed by the manipulation of the central-waveguide mode index, leaving the signal-carrying waveguides unaffected by the loss. We discuss how Adiabatic Elimination provides a solution for mitigating signal losses and designing relatively compact, broadband, and energy-efficient integrated optical modulators.

Empirical Examination of Fundamental Indexation in the German Market

NASA Astrophysics Data System (ADS)

Mihm, Max; Locarek-Junge, Hermann

Index Funds, Exchange Traded Funds and Derivatives give investors easy access to well diversified index portfolios. These index-based investment products exhibit low fees, which make them an attractive alternative to actively managed funds. Against this background, a new class of stock indices has been established based on the concept of “Fundamental Indexation”. The selection and weighting of index constituents is conducted by means of fundamental criteria like total assets, book value or number of employees. This paper examines the performance of fundamental indices in the German equity market. For this purpose, a backtest of five fundamental indices is conducted over the last 20 years. Furthermore the index returns are analysed under the assumption of an efficient as well as an inefficient market. Index returns in efficient markets are explained by applying the three factor model for stock returns of Fama and French (J Financ Econ 33(1):3-56, 1993). The results show that the outperformance of fundamental indices is partly due to a higher risk exposure, particularly to companies with a low price to book ratio. By relaxing the assumption of market efficiency, a return drag of capitalisation weighted indices can be deduced. Given a mean-reverting movement of prices, a direct connection between market capitalisation and index weighting leads to inferior returns.

Pipelining Architecture of Indexing Using Agglomerative Clustering

NASA Astrophysics Data System (ADS)

Goyal, Deepika; Goyal, Deepti; Gupta, Parul

2010-11-01

The World Wide Web is an interlinked collection of billions of documents. Ironically the huge size of this collection has become an obstacle for information retrieval. To access the information from Internet, search engine is used. Search engine retrieve the pages from indexer. This paper introduce a novel pipelining technique for structuring the core index-building system that substantially reduces the index construction time and also clustering algorithm that aims at partitioning the set of documents into ordered clusters so that the documents within the same cluster are similar and are being assigned the closer document identifiers. After assigning to the clusters it creates the hierarchy of index so that searching is efficient. It will make the super cluster then mega cluster by itself. The pipeline architecture will create the index in such a way that it will be efficient in space and time saving manner. It will direct the search from higher level to lower level of index or higher level of clusters to lower level of cluster so that the user gets the possible match result in time saving manner. As one cluster is making by taking only two clusters so it search is limited to two clusters for lower level of index and so on. So it is efficient in time saving manner.

Hospital competition and inpatient services efficiency in Taiwan: a longitudinal study.

PubMed

Chu, Chiao-Lee; Chiang, Tung-Liang; Chang, Ray-E

2011-10-01

There is no consistent evidence of the relationship between market competition and hospital efficiency. Some studies indicated that more competition led to a faster patient turnover rate, higher hospital costs, and lower hospital efficiency. Since the 1980s some studies found market competition could increase the efficiency of inpatient services. However, there were few studies testing the market competition during a hospital's earlier stages on its efficiency during later stages, or the dynamic of efficiency. In this study, we examined the effect of early-stage market competition on later-stage hospital efficiency in Taiwan, and we determine the efficiency change using longitudinal study design. The data for the analysis came from the annual national hospital survey of 1996 and 2001 provided by the Department of Health. There were 102 teaching hospital be analysed. The results show that no evidence supports the proposition that higher market competition would improve the efficiency of hospitals in delivering inpatient services in Taiwan. Importantly, neither was the inefficiency score nor the Malmquist productivity index of inpatient services associated with the level of hospital market competition, regardless of the adjustment for hospital characteristics. However, the results may be related with the hospital increasing beds investment behavior. Copyright © 2010 John Wiley & Sons, Ltd.

High-efficiency, broad band, high-damage threshold high-index gratings for femtosecond pulse compression.

PubMed

Canova, Frederico; Clady, Raphael; Chambaret, Jean-Paul; Flury, Manuel; Tonchev, Svtelen; Fechner, Renate; Parriaux, Olivier

2007-11-12

High efficiency, broad-band TE-polarization diffraction over a wavelength range centered at 800 nm is obtained by high index gratings placed on a non-corrugated mirror. More than 96% efficiency wide band top-hat diffraction efficiency spectra, as well as more than 1 J/cm(2) damage threshold under 50 fs pulses are demonstrated experimentally. This opens the way to high-efficiency Chirped Pulse Amplification for high average power laser machining by means of all-dielectric structures as well as for ultra-short high energy pulses by means of metal-dielectric structures.

Ultra-thin high-efficiency mid-infrared transmissive Huygens meta-optics.

PubMed

Zhang, Li; Ding, Jun; Zheng, Hanyu; An, Sensong; Lin, Hongtao; Zheng, Bowen; Du, Qingyang; Yin, Gufan; Michon, Jerome; Zhang, Yifei; Fang, Zhuoran; Shalaginov, Mikhail Y; Deng, Longjiang; Gu, Tian; Zhang, Hualiang; Hu, Juejun

2018-04-16

The mid-infrared (mid-IR) is a strategically important band for numerous applications ranging from night vision to biochemical sensing. Here we theoretically analyzed and experimentally realized a Huygens metasurface platform capable of fulfilling a diverse cross-section of optical functions in the mid-IR. The meta-optical elements were constructed using high-index chalcogenide films deposited on fluoride substrates: the choices of wide-band transparent materials allow the design to be scaled across a broad infrared spectrum. Capitalizing on a two-component Huygens' meta-atom design, the meta-optical devices feature an ultra-thin profile (λ 0 /8 in thickness) and measured optical efficiencies up to 75% in transmissive mode for linearly polarized light, representing major improvements over state-of-the-art. We have also demonstrated mid-IR transmissive meta-lenses with diffraction-limited focusing and imaging performance. The projected size, weight and power advantages, coupled with the manufacturing scalability leveraging standard microfabrication technologies, make the Huygens meta-optical devices promising for next-generation mid-IR system applications.

A portable wireless power transmission system for video capsule endoscopes.

PubMed

Shi, Yu; Yan, Guozheng; Zhu, Bingquan; Liu, Gang

2015-01-01

Wireless power transmission (WPT) technology can solve the energy shortage problem of the video capsule endoscope (VCE) powered by button batteries, but the fixed platform limited its clinical application. This paper presents a portable WPT system for VCE. Besides portability, power transfer efficiency and stability are considered as the main indexes of optimization design of the system, which consists of the transmitting coil structure, portable control box, operating frequency, magnetic core and winding of receiving coil. Upon the above principles, the correlation parameters are measured, compared and chosen. Finally, through experiments on the platform, the methods are tested and evaluated. In the gastrointestinal tract of small pig, the VCE is supplied with sufficient energy by the WPT system, and the energy conversion efficiency is 2.8%. The video obtained is clear with a resolution of 320×240 and a frame rate of 30 frames per second. The experiments verify the feasibility of design scheme, and further improvement direction is discussed.

Energy-saving quality road lighting with colloidal quantum dot nanophosphors

NASA Astrophysics Data System (ADS)

Erdem, Talha; Kelestemur, Yusuf; Soran-Erdem, Zeliha; Ji, Yun; Demir, Hilmi Volkan

2014-12-01

Here the first photometric study of road-lighting white light-emitting diodes (WLEDs) integrated with semiconductor colloidal quantum dots (QDs) is reported enabling higher luminance than conventional light sources, specifically in mesopic vision regimes essential to street lighting. Investigating over 100 million designs uncovers that quality road-lighting QD-WLEDs, with a color quality scale and color rendering index ≥85, enables 13-35% higher mesopic luminance than the sources commonly used in street lighting. Furthermore, these QD-WLEDs were shown to be electrically more efficient than conventional sources with power conversion efficiencies ≥16-29%. Considering this fact, an experimental proof-of-concept QD-WLED was demonstrated, which is the first account of QD based color conversion custom designed for street lighting applications. The obtained white LED achieved the targeted mesopic luminance levels in accordance with the road lighting standards of the USA and the UK. These results indicate that road-lighting QD-WLEDs are strongly promising for energy-saving quality road lighting.

Ejectors of power plants turbine units efficiency and reliability increasing

NASA Astrophysics Data System (ADS)

Aronson, K. E.; Ryabchikov, A. Yu.; Kuptsov, V. K.; Murmanskii, I. B.; Brodov, Yu. M.; Zhelonkin, N. V.; Khaet, S. I.

2017-11-01

The functioning of steam turbines condensation systems influence on the efficiency and reliability of a power plant a lot. At the same time, the condensation system operating is provided by basic ejectors, which maintain the vacuum level in the condenser. Development of methods of efficiency and reliability increasing for ejector functioning is an actual problem of up-to-date power engineering. In the paper there is presented statistical analysis of ejector breakdowns, revealed during repairing processes, the influence of such damages on the steam turbine operating reliability. It is determined, that 3% of steam turbine equipment breakdowns are the ejector breakdowns. At the same time, about 7% of turbine breakdowns are caused by different ejector malfunctions. Developed and approved design solutions, which can increase the ejector functioning indexes, are presented. Intercoolers are designed in separated cases, so the air-steam mixture can’t move from the high-pressure zones to the low-pressure zones and the maintainability of the apparatuses is increased. By U-type tubes application, the thermal expansion effect of intercooler tubes is compensated and the heat-transfer area is increased. By the applied nozzle fixing construction, it is possible to change the distance between a nozzle and a mixing chamber (nozzle exit position) for operating performance optimization. In operating conditions there are provided experimental researches of more than 30 serial ejectors and also high-efficient 3-staged ejector EPO-3-80, designed by authors. The measurement scheme of the designed ejector includes 21 indicator. The results of experimental tests with different nozzle exit positions of the ejector EPO-3-80 stream devices are presented. The pressure of primary stream (water steam) is optimized. Experimental data are well-approved by the calculation results.

Coupled ridge waveguide distributed feedback quantum cascade laser arrays

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

Liu, Ying-Hui; Zhang, Jin-Chuan, E-mail: zhangjinchuan@semi.ac.cn; Yan, Fang-Liang

2015-04-06

A coupled ridge waveguide quantum cascade laser (QCL) array consisting of fifteen elements with parallel integration was presented. In-phase fundamental mode operation in each element is secured by both the index-guided nature of the ridge and delicate loss management by properly designed geometries of the ridges and interspaces. Single-lobe lateral far-field with a nearly diffraction limited beam pattern was obtained. By incorporating a one-dimensional buried distributed feedback grating, the in-phase-operating coupled ridge waveguide QCL design provides an efficient solution to obtaining high output power and stable single longitudinal mode emission. The simplicity of this structure and fabrication process makes thismore » approach attractive to many practical applications.« less

Photopolymer based VPHGs: from materials to sky results

NASA Astrophysics Data System (ADS)

Zanutta, A.; Orselli, E.; Fäcke, T.; Bianco, A.

2016-07-01

Volume Phase Holographic Gratings cover a relevant position as transmission dispersing elements in astronomical spectrographs and each astronomical observation could take advantage of specific dispersive elements with features tailored for achieving the best performances. The design and manufacturing of high efficiency and reliable VPHGs require photosensitive materials where it is possible to control both the refractive index modulation and the film thickness. By means of Bayfol® HX photopolymers, we designed and manufactured six VPHGs for astronomical instrumentation in a GRISM configuration. We demonstrated how photopolymers are reliable holographic materials for making astronomical VPHGs with performances comparable to those provided by VPHGs based on Dichromated Gelatins (DCGs), but with a much simpler production process.

PROTOCOL TO EVALUATE THE MOISTURE DURABILITY OF ENERGY-EFFICIENT WALLS

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

Boudreaux, Philip R; Pallin, Simon B; Hun, Diana E

Walls account for about 8% of the energy used in residential buildings. This energy penalty can be reduced with higher insulation levels and increased airtightness. However, these measures can compromise the moisture durability and long-term performance of wall assemblies because they can lead to lower moisture tolerance due to reduced drying potential. To avert these problems, a moisture durability protocol was developed to evaluate the probability that an energy-efficient wall design will experience mold growth. This protocol examines the effects of moisture sources in walls through a combination of simulations and lab experiments, uses the mold growth index as themore » moisture durability indicator, and is based on a probabilistic approach that utilizes stochastically varying input parameters. The simulation tools used include a new validated method for taking into account the effects of air leakage in wall assemblies This paper provides an overview of the developed protocol, discussion of the probabilistic simulation approach and describes results from the evaluation of two wall assemblies in Climate Zones 2, 4, and 6. The protocol will be used to supply builders with wall designs that are energy efficient, moisture durable and cost-effective.« less

Bi-Tapered Fiber Sensor Using a Supercontinuum Light Source for a Broad Spectral Range

NASA Astrophysics Data System (ADS)

Garcia Mina, Diego Felipe

We describe the fabrication bi-tapered optical fiber sensors designed for shorter wavelength operation and we study their optical properties. The new sensing system designed and built for the project is a specialty optical fiber that is single-mode in the visible/near infrared wavelength region of interest. In fabricating the tapered fiber we control the taper parameters, such as the down-taper and up-taper rate, shape and length, and the fiber waist diameter and length. The sensing is mode is via the electromagnetic field, which is evanescent outside the optical fiber and is confined close to the fiber's surface (within a couple hundred nanometers). The fiber sensor system has multiple advantages as a compact, simple device with an ability to detected tiny changes in the refractive index. We developed a supercontinuum light source to provide a wide spectral wavelength range from visible to near IR. The source design was based on coupling light from a femtosecond laser in a photonic crystal fiber designed for high nonlinearity. The output light was efficiently coupled into the bi-tapered fiber sensor and good signal to noise was achieved across the wavelength region. The bi-tapered fiber starts and ends with a single mode fiber in the waist region there are many modes with different propagation constants that couple to the environment outside the fiber. The signals have a strong periodic component as the wavelength is scanned; we exploit the periodicity in the signal using a discrete Fourier transform analysis to correlate signal phase changes with the refractive index changes in the local environment. For small index changes we also measure a strong correlation with the dominant Fourier amplitude component. Our experiments show that our phase-based signal processing technique works well at shorter wavelengths and we extract a new feature, the Fourier amplitude, to measure the refractive index difference. We conducted experiments using aqueous medium with controlled refractive index, such as water-glycerol mixtures. We find sensitivity to changes in the refractive index close to 0.00002 in so-called Refractive Index Units (RIUs). That is smaller than reported in recent literature, but by no means a limiting value. The technique is not limited to aqueous solutions surrounding the fiber, but it can also be adapted to study volatile organic compounds. Future improvements in the fiber sensing system are discussed, including adding thin films to the surface for label-free detection and to draw the electromagnetic field to the fiber's surface.

Thermodynamic Studies for Drug Design and Screening

PubMed Central

Garbett, Nichola C.; Chaires, Jonathan B.

2012-01-01

Introduction A key part of drug design and development is the optimization of molecular interactions between an engineered drug candidate and its binding target. Thermodynamic characterization provides information about the balance of energetic forces driving binding interactions and is essential for understanding and optimizing molecular interactions. Areas covered This review discusses the information that can be obtained from thermodynamic measurements and how this can be applied to the drug development process. Current approaches for the measurement and optimization of thermodynamic parameters are presented, specifically higher throughput and calorimetric methods. Relevant literature for this review was identified in part by bibliographic searches for the period 2004 – 2011 using the Science Citation Index and PUBMED and the keywords listed below. Expert opinion The most effective drug design and development platform comes from an integrated process utilizing all available information from structural, thermodynamic and biological studies. Continuing evolution in our understanding of the energetic basis of molecular interactions and advances in thermodynamic methods for widespread application are essential to realize the goal of thermodynamically-driven drug design. Comprehensive thermodynamic evaluation is vital early in the drug development process to speed drug development towards an optimal energetic interaction profile while retaining good pharmacological properties. Practical thermodynamic approaches, such as enthalpic optimization, thermodynamic optimization plots and the enthalpic efficiency index, have now matured to provide proven utility in design process. Improved throughput in calorimetric methods remains essential for even greater integration of thermodynamics into drug design. PMID:22458502

Optimization of the efficiency of search operations in the relational database of radio electronic systems

NASA Astrophysics Data System (ADS)

Wajszczyk, Bronisław; Biernacki, Konrad

2018-04-01

The increase of interoperability of radio electronic systems used in the Armed Forces requires the processing of very large amounts of data. Requirements for the integration of information from many systems and sensors, including radar recognition, electronic and optical recognition, force to look for more efficient methods to support information retrieval in even-larger database resources. This paper presents the results of research on methods of improving the efficiency of databases using various types of indexes. The data structure indexing technique is a solution used in RDBMS systems (relational database management system). However, the analysis of the performance of indices, the description of potential applications, and in particular the presentation of a specific scale of performance growth for individual indices are limited to few studies in this field. This paper contains analysis of methods affecting the work efficiency of a relational database management system. As a result of the research, a significant increase in the efficiency of operations on data was achieved through the strategy of indexing data structures. The presentation of the research topic discussed in this paper mainly consists of testing the operation of various indexes against the background of different queries and data structures. The conclusions from the conducted experiments allow to assess the effectiveness of the solutions proposed and applied in the research. The results of the research indicate the existence of a real increase in the performance of operations on data using indexation of data structures. In addition, the level of this growth is presented, broken down by index types.

GALAPAGOS-C: analysis of galaxy morphologies using high-performance computing methods

NASA Astrophysics Data System (ADS)

Hiemer, Andreas; Barden, Marco; Kelvin, Lee S.; Häußler, Boris; Schindler, Sabine

2014-11-01

We present GALAPAGOS-C, a code designed to process a complete set of survey images through automation of source detection (via SEXTRACTOR), postage stamp cutting, object mask preparation, sky background estimation and complex two-dimensional light profile Sérsic modelling (via GALFIT). GALAPAGOS-C is designed around the concept of MPI-parallelization, allowing the processing of large data sets in a quick and efficient manner. Further, GALAPAGOS-C is capable of fitting multiple-Sérsic profiles to each galaxy, each representing distinct galaxy components (e.g. bulge, disc, bar), in addition to the option to fit asymmetric Fourier mode distortions. The modelling reliability of our core single-Sérsic fitting capability is tested thoroughly using image simulations. We apply GALAPAGOS-C to the Space Telescope A901/902 Galaxy Evolution Survey to investigate the evolution of galaxy structure with cosmic time and the dependence on environment. We measure the distribution of Sérsic indices as a function of local object density in the A901/902 cluster sample to provide one of the first measures of the Sérsic index-density relation. We find that the fraction of galaxies with a high Sérsic index (2.5 < n < 7.0) is higher in denser environments (˜35 per cent), halving towards sparsely populated regions (˜15 per cent). The population of low Sérsic index galaxies (0.4 < n< 1.6) is lower in denser environments (˜35 per cent), increasing towards sparsely populated regions (˜60 per cent). The population of intermediate Sérsic index galaxies (1.6 < n < 2.5) approximately follows the trend of the high Sérsic index types.

Designing and Validation a Visual Fatigue Questionnaire for Video Display Terminals Operators

PubMed Central

Rajabi-Vardanjani, Hassan; Habibi, Ehsanollah; Pourabdian, Siyamak; Dehghan, Habibollah; Maracy, Mohammad Reza

2014-01-01

Background: Along with the rapid growth of technology its related tools such as computer, monitors and video display terminals (VDTs) grow as well. Based on the studies, the most common complaint reported is of the VDT users. Methods: This study attempts to design a proper tool to assess the visual fatigue of the VDT users. First draft of the questionnaire was prepared after a thorough study on the books, papers and similar questionnaires. The validity and reliability of the questionnaire was confirmed using the content validity index (CVI) beside that of the Cronbach's Coefficient Alpha. Then, a cross-sectional study was carried out on 248 of the VDT users in different professions. A theoretical model with four categories of symptoms of visual fatigue was derived from the previous studies and questionnaires. Having used the AMOS16 software, the construct validity of the questionnaire was evaluated using the confirmatory factor analysis. The correlation co-efficiency of the internal domains was calculated using the SPSS 11.5 software. To assess the quality check index and determining the visual fatigue levels, visual fatigue of the VDT users was measured by the questionnaire and visual fatigue meter (VFM) device. Cut-off points were identified by receiver operating characteristic curves. Results: CVI and reliability co-efficiency were both equal to 0.75. Model fit indices including root mean of squared error approximation, goodness of fit index and adjusted goodness of fit index were obtained 0.026, 0.96 and 0.92 respectfully. The correlation between the results measured with the questionnaire and VFM-90.1 device was −0.87. Cut-off points of the questionnaire were 0.65, 2.36 and 3.88. The confirmed questionnaire consists of four main areas: Eye strain (4 questions), visual impairment (5 questions) and the surface impairment of the eye (3 questions) and the out of eye problems (3 questions). Conclusions: The visual fatigue questionnaire contains 15 questions and has a very remarkable validity and reliability. Using this questionnaire and its findings, one will be able to identify, assess and finally prevent the effective factors of VDT users’ visual fatigue. PMID:25104995

Long period grating refractive-index sensor: optimal design for single wavelength interrogation.

PubMed

Kapoor, Amita; Sharma, Enakshi K

2009-11-01

We report the design criteria for the use of long period gratings (LPGs) as refractive-index sensors with output power at a single interrogating wavelength as the measurement parameter. The design gives maximum sensitivity in a given refractive-index range when the interrogating wavelength is fixed. Use of the design criteria is illustrated by the design of refractive-index sensors for specific application to refractive-index variation of a sugar solution with a concentration and detection of mole fraction of xylene in heptane (paraffin).

Kmerind: A Flexible Parallel Library for K-mer Indexing of Biological Sequences on Distributed Memory Systems.

PubMed

Pan, Tony; Flick, Patrick; Jain, Chirag; Liu, Yongchao; Aluru, Srinivas

2017-10-09

Counting and indexing fixed length substrings, or k-mers, in biological sequences is a key step in many bioinformatics tasks including genome alignment and mapping, genome assembly, and error correction. While advances in next generation sequencing technologies have dramatically reduced the cost and improved latency and throughput, few bioinformatics tools can efficiently process the datasets at the current generation rate of 1.8 terabases every 3 days. We present Kmerind, a high performance parallel k-mer indexing library for distributed memory environments. The Kmerind library provides a set of simple and consistent APIs with sequential semantics and parallel implementations that are designed to be flexible and extensible. Kmerind's k-mer counter performs similarly or better than the best existing k-mer counting tools even on shared memory systems. In a distributed memory environment, Kmerind counts k-mers in a 120 GB sequence read dataset in less than 13 seconds on 1024 Xeon CPU cores, and fully indexes their positions in approximately 17 seconds. Querying for 1% of the k-mers in these indices can be completed in 0.23 seconds and 28 seconds, respectively. Kmerind is the first k-mer indexing library for distributed memory environments, and the first extensible library for general k-mer indexing and counting. Kmerind is available at https://github.com/ParBLiSS/kmerind.

Field-induced refractive index variation in the dark conglomerate phase for polarization-independent switchable liquid crystal lenses.

PubMed

Milton, H E; Nagaraj, M; Kaur, S; Jones, J C; Morgan, P B; Gleeson, H F

2014-11-01

Liquid crystal lenses are an emerging technology that can provide variable focal power in response to applied voltage. Many designs for liquid-crystal-based lenses are polarization dependent, so that 50% of light is not focused as required, making polarization-independent technologies very attractive. Recently, the dark conglomerate (DC) phase, which is an optically isotropic liquid crystalline state, has been shown to exhibit a large change in refractive index in response to an applied electric field (Δn=0.04). This paper describes computational modeling of the electrostatic solutions for two different types of 100 μm diameter liquid crystal lenses, which include the DC phase, demonstrating that it shows great potential for efficient isotropic optical switching in lenses. A feature of the field dependence of the refractive index change in the DC phase is that it is approximately linear in a certain range, leading to the prediction of excellent optical quality for driving fields in this regime. Interestingly, a simulated microlens is shown to exhibit two modes of operation: a positive lens based upon a uniform bulk change in refractive index at high voltages, and a negative lens resulting from the induction of a gradient index effect at intermediate voltages.

Design-for-manufacture of gradient-index optical systems using time-varying boundary condition diffusion

NASA Astrophysics Data System (ADS)

Harkrider, Curtis Jason

2000-08-01

The incorporation of gradient-index (GRIN) material into optical systems offers novel and practical solutions to lens design problems. However, widespread use of gradient-index optics has been limited by poor correlation between gradient-index designs and the refractive index profiles produced by ion exchange between glass and molten salt. Previously, a design-for- manufacture model was introduced that connected the design and fabrication processes through use of diffusion modeling linked with lens design software. This project extends the design-for-manufacture model into a time- varying boundary condition (TVBC) diffusion model. TVBC incorporates the time-dependent phenomenon of melt poisoning and introduces a new index profile control method, multiple-step diffusion. The ions displaced from the glass during the ion exchange fabrication process can reduce the total change in refractive index (Δn). Chemical equilibrium is used to model this melt poisoning process. Equilibrium experiments are performed in a titania silicate glass and chemically analyzed. The equilibrium model is fit to ion concentration data that is used to calculate ion exchange boundary conditions. The boundary conditions are changed purposely to control the refractive index profile in multiple-step TVBC diffusion. The glass sample is alternated between ion exchange with a molten salt bath and annealing. The time of each diffusion step can be used to exert control on the index profile. The TVBC computer model is experimentally verified and incorporated into the design- for-manufacture subroutine that runs in lens design software. The TVBC design-for-manufacture model is useful for fabrication-based tolerance analysis of gradient-index lenses and for the design of manufactureable GRIN lenses. Several optical elements are designed and fabricated using multiple-step diffusion, verifying the accuracy of the model. The strength of multiple-step diffusion process lies in its versatility. An axicon, imaging lens, and curved radial lens, all with different index profile requirements, are designed out of a single glass composition.

Indexing and retrieval of MPEG compressed video

NASA Astrophysics Data System (ADS)

Kobla, Vikrant; Doermann, David S.

1998-04-01

To keep pace with the increased popularity of digital video as an archival medium, the development of techniques for fast and efficient analysis of ideo streams is essential. In particular, solutions to the problems of storing, indexing, browsing, and retrieving video data from large multimedia databases are necessary to a low access to these collections. Given that video is often stored efficiently in a compressed format, the costly overhead of decompression can be reduced by analyzing the compressed representation directly. In earlier work, we presented compressed domain parsing techniques which identified shots, subshots, and scenes. In this article, we present efficient key frame selection, feature extraction, indexing, and retrieval techniques that are directly applicable to MPEG compressed video. We develop a frame type independent representation which normalizes spatial and temporal features including frame type, frame size, macroblock encoding, and motion compensation vectors. Features for indexing are derived directly from this representation and mapped to a low- dimensional space where they can be accessed using standard database techniques. Spatial information is used as primary index into the database and temporal information is used to rank retrieved clips and enhance the robustness of the system. The techniques presented enable efficient indexing, querying, and retrieval of compressed video as demonstrated by our system which typically takes a fraction of a second to retrieve similar video scenes from a database, with over 95 percent recall.

Aperiodic Volume Optics

NASA Astrophysics Data System (ADS)

Gerke, Tim D.

Presented in this thesis is an investigation into aperiodic volume optical devices. The three main topics of research and discussion are the aperiodic volume optical devices that we call computer-generated volume holograms (CGVH), defects within periodic 3D photonic crystals, and non-periodic, but ordered 3D quasicrystals. The first of these devices, CGVHs, are designed and investigated numerically and experimentally. We study the performance of multi-layered amplitude computer-generated volume holograms in terms of efficiency and angular/frequency selectivity. Simulation results show that such aperiodic devices can increase diffraction efficiency relative to periodic amplitude volume holograms while maintaining angular and wavelength selectivity. CGVHs are also designed as voxelated volumes using a new projection optimization algorithm. They are investigated using a volumetric diffraction simulation and a standard 3D beam propagation technique as well as experimentally. Both simulation and experiment verify that the structures function according to their design. These represent the first diffractive structures that have the capacity for generating arbitrary transmission and reflection wave fronts and that provide the ability for multiplexing arbitrary functionality given different illumination conditions. Also investigated and discussed in this thesis are 3D photonic crystals and quasicrystals. We demonstrate that these devices can be fabricated using a femtosecond laser direct writing system that is particularly appropriate for fabrication of such arbitrary 3D structures. We also show that these devices can provide 3D partial bandgaps which could become complete bandgaps if fabricated using high index materials or by coating lower index materials with high index metals. Our fabrication method is particularly suited to the fabrication of engineered defects within the periodic or quasi-periodic systems. We demonstrate the potential for fabricating defects within periodic and quasi-periodic systems for the manipulation of light in the IR regime. The general thesis of this document is that aperiodic three-dimensional structures provide additional degrees of freedom that can be utilized to improve on the performance of periodic volume devices. The results we will discuss suggest that, under certain circumstances, a departure from the Bragg paradigm provides enhanced volume diffraction properties.

Selection Criteria for Sustainable Fuels for High-Efficiency Spark-Ignition Engines with Examination of their Storage Stability, Impact on Engine Knock, and Fine Particle Emissions

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

McCormick, Robert L

It is possible to significantly improve the efficiency of spark-ignition engines given fuels with improved autoignition, evaporative cooling, and particle emission properties. At the same time, a vast range of different fuel chemistries are accessible from biomass - leading to questions about how fuel chemistries outside the range available from petroleum and ethanol can impact engine operation. This presentation will briefly describe the factors leading to poor efficiency in current SI engines, and the technologies available for improving efficiency. Improved fuel properties that enable high efficiency engine designs to be pursued aggressively will be reviewed, including octane index and sensitivity.more » A screening process based on fuel properties was applied to a large set of proposed biomass-derived gasoline blendstocks, and the properties of the best blendstocks were evaluated. Some of these fuels exhibit poor stability towards oxidation in the liquid phase, and storage stability studies for alkyl furans and cyclopentanone will be presented in brief. The importance of fuel heat of vaporization for direct injection engines, along with new research on measurement of this parameter, will be presented including an SI engine study of the impact of heat of vaporization on octane index and engine knock. Fuel effects on fine particle emissions and how our understanding breaks down for oxygenates will be discussed. Engine combustion experiments, droplet evaporation simulations, and heat of vaporization measurements conducted to better understand how oxygenates affect particle emissions will be described. This research defines a process that can be used to evaluate fuels for other types of combustion such as diesel, gasoline compression ignition, or strategies with mixed modes.« less

Asymmetric diffraction by atomic gratings with optical PT symmetry in the Raman-Nath regime

NASA Astrophysics Data System (ADS)

Shui, Tao; Yang, Wen-Xing; Liu, Shaopeng; Li, Ling; Zhu, Zhonghu

2018-03-01

We propose and analyze an efficient scheme for the lopsided Raman-Nath diffraction of one-dimensional (1 D ) and two-dimensional (2 D ) atomic gratings with periodic parity-time (PT )-symmetric refractive index. The atomic grating is constructed by the cold-atomic vapor with two isotopes of rubidium, which is driven by weak probe field and space-dependent control field. Using experimentally achievable parameters, we identify the conditions under which PT -symmetric refractive index allows us to observe the lopsided Raman-Nath diffraction phenomenon and improve the diffraction efficiencies beyond what is achievable in a conventional atomic grating. The nontrivial atomic grating is a superposition of an amplitude grating and a phase grating. It is found that the lopsided Raman-Nath diffraction at the exceptional point (EP) of PT -symmetric grating originates from constructive and destructive interferences between the amplitude and phase gratings. Furthermore, we show that the PT -phase transition from unbroken to broken PT -symmetric regimes can modify the asymmetric distribution of the diffraction spectrum and that the diffraction efficiencies in the non-negative diffraction orders can be significantly enhanced when the atomic grating is pushed into a broken PT -symmetric phase. In addition, we also analyze the influence of the grating thickness on the diffraction spectrum. Our scheme may provide the possibility to design a gain-beam splitter with tunable splitting ratio and other optical components in integrated optics.

Instructional Efficiency of Tutoring in an Outreach Gene Technology Laboratory

NASA Astrophysics Data System (ADS)

Scharfenberg, Franz-Josef; Bogner, Franz X.

2013-06-01

Our research objective focused on examining the instructional efficiency of tutoring as a form of instructional change as opposed to a non-tutoring approach in an outreach laboratory. We designed our laboratory based on cognitive load (CL) theory. Altogether, 269 twelfth-graders participated in our day-long module Genetic Fingerprinting. In a quasi-experimental design, the control group ( n = 121) followed the non-tutoring approach previously used, while the treatment group ( n = 148) followed the newly developed tutoring approach. Each tutor was in charge of two student work groups and recorded the tutoring activities requested by the tutees throughout the day. We measured the students' invested mental effort (as an index of CL), cognitive achievement (in a pre-post-follow-up design), and the students' cooperation in their work groups as well as calculated the student instructional involvement (as a motivational variable). Additionally, we examined which aspects of the hands-on phases were of particular relevance to the students' invested mental effort. Unexpectedly, the combined mental effort and cognitive achievement data indicated that our implemented tutoring approach resulted in a lower instructional efficiency despite the relevance of tutoring for students' mental effort invested during the experimental phases. Most of the tutor assistance was unnecessarily requested for performing the procedural steps and using the equipment. Our results indicate an assistance dilemma and consequently underscore the necessity for effective tutor preparation in outreach laboratories.

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

Not Available

Achieving aggressive energy efficiency targets requires tight coordination and clear communication among owners, designers, builders, and subcontractors. For this townhome project, MassDevelopment, the quasi-governmental agency owner, selected Metric Development of Boston, teaming with the U.S. Department of Energy (DOE) Consortium for Advanced Residential Buildings (CARB) and Cambridge Seven Architects, to build very high performing market-rate homes. Fort Devens is part of a decommissioned army base in working-class Harvard, Massachusetts, approximately one hour northwest of Boston. The team proposed 12 net zero energy-ready townhomes, meaning that the application of renewable energy systems would result in annual net zero energy use inmore » the homes. The homes were also designed to achieve a Home Energy Rating System (HERS) Index Score of 41 before adding renewables. For this project, CARB drew on its experience working with Rural Development Inc. on a series of affordable townhomes in northern Massachusetts. The team carefully planned the site to maximize solar access, daylighting, and efficient building forms. The basic strategy was to design a very efficient thermal enclosure while minimizing incremental cost increases compared with standard construction. Using BEopt modeling software, the team established the requirements of the enclosure and investigated multiple assembly options. They settled on double-wall construction with dense-pack cellulose fill. High performance vinyl windows (U-0.24, solar heat gain coefficient [SHGC]-0.22), a vented R-59 attic, and exceptional air sealing completed the package.« less

Semantics-Based Intelligent Indexing and Retrieval of Digital Images - A Case Study

NASA Astrophysics Data System (ADS)

Osman, Taha; Thakker, Dhavalkumar; Schaefer, Gerald

The proliferation of digital media has led to a huge interest in classifying and indexing media objects for generic search and usage. In particular, we are witnessing colossal growth in digital image repositories that are difficult to navigate using free-text search mechanisms, which often return inaccurate matches as they typically rely on statistical analysis of query keyword recurrence in the image annotation or surrounding text. In this chapter we present a semantically enabled image annotation and retrieval engine that is designed to satisfy the requirements of commercial image collections market in terms of both accuracy and efficiency of the retrieval process. Our search engine relies on methodically structured ontologies for image annotation, thus allowing for more intelligent reasoning about the image content and subsequently obtaining a more accurate set of results and a richer set of alternatives matchmaking the original query. We also show how our well-analysed and designed domain ontology contributes to the implicit expansion of user queries as well as presenting our initial thoughts on exploiting lexical databases for explicit semantic-based query expansion.

[Characteristics of phosphorus uptake and use efficiency of rice with high yield and high phosphorus use efficiency].

PubMed

Li, Li; Zhang, Xi-Zhou; Li, Tinx-Xuan; Yu, Hai-Ying; Ji, Lin; Chen, Guang-Deng

2014-07-01

A total of twenty seven middle maturing rice varieties as parent materials were divided into four types based on P use efficiency for grain yield in 2011 by field experiment with normal phosphorus (P) application. The rice variety with high yield and high P efficiency was identified by pot experiment with normal and low P applications, and the contribution rates of various P efficiencies to yield were investigated in 2012. There were significant genotype differences in yield and P efficiency of the test materials. GRLu17/AiTTP//Lu17_2 (QR20) was identified as a variety with high yield and high P efficiency, and its yields at the low and normal rates of P application were 1.96 and 1.92 times of that of Yuxiang B, respectively. The contribution rate of P accumulation to yield was greater than that of P grain production efficiency and P harvest index across field and pot experiments. The contribution rates of P accumulation and P grain production efficiency to yield were not significantly different under the normal P condition, whereas obvious differences were observed under the low P condition (66.5% and 26.6%). The minimal contribution to yield was P harvest index (11.8%). Under the normal P condition, the contribution rates of P accumulation to yield and P harvest index were the highest at the jointing-heading stage, which were 93.4% and 85.7%, respectively. In addition, the contribution rate of P accumulation to grain production efficiency was 41.8%. Under the low P condition, the maximal contribution rates of P accumulation to yield and grain production efficiency were observed at the tillering-jointing stage, which were 56.9% and 20.1% respectively. Furthermore, the contribution rate of P accumulation to P harvest index was 16.0%. The yield, P accumulation, and P harvest index of QR20 significantly increased under the normal P condition by 20.6%, 18.1% and 18.2% respectively compared with that in the low P condition. The rank of the contribution rates of P efficiencies to the yield was in order of P uptake efficiency > P utilization efficiency > P transportation efficiency. The greatest contribution rate of P accumulation to the yield was noticed at the jointing-heading stage with the normal P application while it reached the maximal value at the tillering-jointing stage with the low P application. Therefore, these two stages may be the critical periods to coordinate high yield and high P efficiency in rice.

Rapid design and optimization of low-thrust rendezvous/interception trajectory for asteroid deflection missions

NASA Astrophysics Data System (ADS)

Li, Shuang; Zhu, Yongsheng; Wang, Yukai

2014-02-01

Asteroid deflection techniques are essential in order to protect the Earth from catastrophic impacts by hazardous asteroids. Rapid design and optimization of low-thrust rendezvous/interception trajectories is considered as one of the key technologies to successfully deflect potentially hazardous asteroids. In this paper, we address a general framework for the rapid design and optimization of low-thrust rendezvous/interception trajectories for future asteroid deflection missions. The design and optimization process includes three closely associated steps. Firstly, shape-based approaches and genetic algorithm (GA) are adopted to perform preliminary design, which provides a reasonable initial guess for subsequent accurate optimization. Secondly, Radau pseudospectral method is utilized to transcribe the low-thrust trajectory optimization problem into a discrete nonlinear programming (NLP) problem. Finally, sequential quadratic programming (SQP) is used to efficiently solve the nonlinear programming problem and obtain the optimal low-thrust rendezvous/interception trajectories. The rapid design and optimization algorithms developed in this paper are validated by three simulation cases with different performance indexes and boundary constraints.

Design and Application of Drought Indexes in Highly Regulated Mediterranean Water Systems

NASA Astrophysics Data System (ADS)

Castelletti, A.; Zaniolo, M.; Giuliani, M.

2017-12-01

Costs of drought are progressively increasing due to the undergoing alteration of hydro-meteorological regimes induced by climate change. Although drought management is largely studied in the literature, most of the traditional drought indexes fail in detecting critical events in highly regulated systems, which generally rely on ad-hoc formulations and cannot be generalized to different context. In this study, we contribute a novel framework for the design of a basin-customized drought index. This index represents a surrogate of the state of the basin and is computed by combining the available information about the water available in the system to reproduce a representative target variable for the drought condition of the basin (e.g., water deficit). To select the relevant variables and combinatione thereof, we use an advanced feature extraction algorithm called Wrapper for Quasi Equally Informative Subset Selection (W-QEISS). W-QEISS relies on a multi-objective evolutionary algorithm to find Pareto-efficient subsets of variables by maximizing the wrapper accuracy, minimizing the number of selected variables, and optimizing relevance and redundancy of the subset. The accuracy objective is evaluated trough the calibration of an extreme learning machine of the water deficit for each candidate subset of variables, with the index selected from the resulting solutions identifying a suitable compromise between accuracy, cardinality, relevance, and redundancy. The approach is tested on Lake Como, Italy, a regulated lake mainly operated for irrigation supply. In the absence of an institutional drought monitoring system, we constructed the combined index using all the hydrological variables from the existing monitoring system as well as common drought indicators at multiple time aggregations. The soil moisture deficit in the root zone computed by a distributed-parameter water balance model of the agricultural districts is used as target variable. Numerical results show that our combined drought index succesfully reproduces the deficit. The index represents a valuable information for supporting appropriate drought management strategies, including the possibility of directly informing the lake operations about the drought conditions and improve the overall reliability of the irrigation supply system.

Analyses of Blood Bank Efficiency, Cost-Effectiveness and Quality

NASA Astrophysics Data System (ADS)

Lam, Hwai-Tai Chen

In view of the increasing costs of hospital care, it is essential to investigate methods to improve the labor efficiency and the cost-effectiveness of the hospital technical core in order to control costs while maintaining the quality of care. This study was conducted to develop indices to measure efficiency, cost-effectiveness, and the quality of blood banks; to identify factors associated with efficiency, cost-effectiveness, and quality; and to generate strategies to improve blood bank labor efficiency and cost-effectiveness. Indices developed in this study for labor efficiency and cost-effectiveness were not affected by patient case mix and illness severity. Factors that were associated with labor efficiency were identified as managerial styles, and organizational designs that balance workload and labor resources. Medical directors' managerial involvement was not associated with labor efficiency, but their continuing education and specialty in blood bank were found to reduce the performance of unnecessary tests. Surprisingly, performing unnecessary tests had no association with labor efficiency. This suggested the existence of labor slack in blood banks. Cost -effectiveness was associated with workers' benefits, wages, and the production of high-end transfusion products by hospital-based donor rooms. Quality indices used in this study included autologous transfusion rates, platelet transfusion rates, and the check points available in an error-control system. Because the autologous transfusion rate was related to patient case mix, severity of illness, and possible inappropriate transfusion, it was not recommended to be used for quality index. Platelet-pheresis transfusion rates were associated with the transfusion preferences of the blood bank medical directors. The total number of check points in an error -control system was negatively associated with government ownership and workers' experience. Recommendations for improving labor efficiency and cost-effectiveness were focused on an incentive system that encourages team effort, and the use of appropriate measurements for laboratory efficiency and operational system designs.

Predictors of outcome of prematurely born infants with pulmonary interstitial emphysema.

PubMed

Williams, Emma; Dassios, Theodore; Clarke, Paul; Chowdhury, Olie; Greenough, Anne

2018-05-13

To determine how oxygenation, ventilation efficiency and tidal volume requirements changed with the development of pulmonary interstitial emphysema (PIE) and whether in affected patients a composite gas exchange index predicted death or bronchopulmonary dysplasia (BPD). Infants who developed PIE from 2010 to 2016 were identified. The oxygenation index, ventilation efficiency index, ventilation to perfusion ratio and inspiratory tidal volume were calculated before radiological evidence of PIE (pre-PIE) and at the worst PIE radiographic appearance (PIE-worst). Thirty infants, median (IQR) gestational age of 24.6 (24.3-26.7) weeks were assessed. Their age at pre-PIE was 11(6-19) days and 23 (13-42) days at PIE-worst. Compared to pre-PIE, at PIE-worst, the oxygenation index was higher [14.5 (10.7-19.2) versus 4.8 (3.1-6.1) respectively, p<0.001], ventilation efficiency index was lower [0.01 (0.01-0.11) versus 0.16 (0.13-0.19) respectively, p<0.001], ventilation to perfusion ratio was lower [0.15 (0.11-0.40) versus 0.26 (0.20-0.37), p=0.033] and tidal volume was higher [9.9 (7.2-13.1) versus 6.4 (5.5-6.8) ml/kg, p=0.007]. An oxygenation index >11.4 at PIE-worst predicted death or BPD with 80% sensitivity and 100% specificity. Development of PIE was associated with poorer oxygenation and ventilation efficiency despite increased tidal volumes. The oxygenation index at PIE-worst predicted death or BPD. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Policy efficiency in the field of food sustainability. The adjusted food agriculture and nutrition index.

PubMed

Agovino, Massimiliano; Cerciello, Massimiliano; Gatto, Andrea

2018-07-15

This work introduces a revised version of the Food Sustainability Index, proposed by the Economist Intelligence Unit and the Barilla Center for Food and Nutrition in 2016. Our Adjusted Food Sustainability Index features two important advantages: 1) it employs the Mazziotta-Pareto method to compute weights, hence granting an objective aggregation criterion and 2) it does not take policy variables into account, thus focusing on the status quo. The policy variables are aggregated into the Policy Index, measuring the quality of the food sustainability policies. We compute the two indices for 25 countries worldwide, then we use the Data Envelopment Analysis to evaluate policy efficiency. Our results show that country-level variation in policy efficiency is wide and policies affect food sustainability significantly, especially when they target nutritional challenges. Copyright © 2018 Elsevier Ltd. All rights reserved.

Design and DSP implementation of star image acquisition and star point fast acquiring and tracking

NASA Astrophysics Data System (ADS)

Zhou, Guohui; Wang, Xiaodong; Hao, Zhihang

2006-02-01

Star sensor is a special high accuracy photoelectric sensor. Attitude acquisition time is an important function index of star sensor. In this paper, the design target is to acquire 10 samples per second dynamic performance. On the basis of analyzing CCD signals timing and star image processing, a new design and a special parallel architecture for improving star image processing are presented in this paper. In the design, the operation moving the data in expanded windows including the star to the on-chip memory of DSP is arranged in the invalid period of CCD frame signal. During the CCD saving the star image to memory, DSP processes the data in the on-chip memory. This parallelism greatly improves the efficiency of processing. The scheme proposed here results in enormous savings of memory normally required. In the scheme, DSP HOLD mode and CPLD technology are used to make a shared memory between CCD and DSP. The efficiency of processing is discussed in numerical tests. Only in 3.5ms is acquired the five lightest stars in the star acquisition stage. In 43us, the data in five expanded windows including stars are moved into the internal memory of DSP, and in 1.6ms, five star coordinates are achieved in the star tracking stage.

The analysis of export commodity competitiveness in Central Java Province at period 2011-2015

NASA Astrophysics Data System (ADS)

Elysi, M. G.; Darsono; Riptanti, E. W.

2018-03-01

This study aims to determine the competitiveness of furniture export in Central Java Province Indonesia in terms of comparative and competitive advantages and to formulate the strategies to enhance the competitiveness of furniture export in Central Java Province. Descriptive analytic method was used for this research. Data used in this research are primary and secondary data. Data were analyzed using RCA (Revealed Comparative Advantage), TSI (Trade Specialization Index) and SOAR (Strength, Opportunity, Aspiration, Result). The results showed that furniture commodity in Central Java Province had strong comparative competitiveness with the value of RCA>1 and had strong competitiveness with positive index values in the range of 0 to 1. Based on SOAR analysis, strategy measures can be formulated, namely maintaining the existing and expanding targeted markets, improving product designs (innovations) and improving raw materials efficiency.

Deep Constrained Siamese Hash Coding Network and Load-Balanced Locality-Sensitive Hashing for Near Duplicate Image Detection.

PubMed

Hu, Weiming; Fan, Yabo; Xing, Junliang; Sun, Liang; Cai, Zhaoquan; Maybank, Stephen

2018-09-01

We construct a new efficient near duplicate image detection method using a hierarchical hash code learning neural network and load-balanced locality-sensitive hashing (LSH) indexing. We propose a deep constrained siamese hash coding neural network combined with deep feature learning. Our neural network is able to extract effective features for near duplicate image detection. The extracted features are used to construct a LSH-based index. We propose a load-balanced LSH method to produce load-balanced buckets in the hashing process. The load-balanced LSH significantly reduces the query time. Based on the proposed load-balanced LSH, we design an effective and feasible algorithm for near duplicate image detection. Extensive experiments on three benchmark data sets demonstrate the effectiveness of our deep siamese hash encoding network and load-balanced LSH.

Compact silicon diffractive sensor: design, fabrication, and prototype.

PubMed

Maikisch, Jonathan S; Gaylord, Thomas K

2012-07-01

An in-plane constant-efficiency variable-diffraction-angle grating and an in-plane high-angular-selectivity grating are combined to enable a new compact silicon diffractive sensor. This sensor is fabricated in silicon-on-insulator and uses telecommunications wavelengths. A single sensor element has a micron-scale device size and uses intensity-based (as opposed to spectral-based) detection for increased integrability. In-plane diffraction gratings provide an intrinsic splitting mechanism to enable a two-dimensional sensor array. Detection of the relative values of diffracted and transmitted intensities is independent of attenuation and is thus robust. The sensor prototype measures refractive index changes of 10(-4). Simulations indicate that this sensor configuration may be capable of measuring refractive index changes three or four orders of magnitude smaller. The characteristics of this sensor type make it promising for lab-on-a-chip applications.

Adaptive semi-supervised recursive tree partitioning: The ART towards large scale patient indexing in personalized healthcare.

PubMed

Wang, Fei

2015-06-01

With the rapid development of information technologies, tremendous amount of data became readily available in various application domains. This big data era presents challenges to many conventional data analytics research directions including data capture, storage, search, sharing, analysis, and visualization. It is no surprise to see that the success of next-generation healthcare systems heavily relies on the effective utilization of gigantic amounts of medical data. The ability of analyzing big data in modern healthcare systems plays a vital role in the improvement of the quality of care delivery. Specifically, patient similarity evaluation aims at estimating the clinical affinity and diagnostic proximity of patients. As one of the successful data driven techniques adopted in healthcare systems, patient similarity evaluation plays a fundamental role in many healthcare research areas such as prognosis, risk assessment, and comparative effectiveness analysis. However, existing algorithms for patient similarity evaluation are inefficient in handling massive patient data. In this paper, we propose an Adaptive Semi-Supervised Recursive Tree Partitioning (ART) framework for large scale patient indexing such that the patients with similar clinical or diagnostic patterns can be correctly and efficiently retrieved. The framework is designed for semi-supervised settings since it is crucial to leverage experts' supervision knowledge in medical scenario, which are fairly limited compared to the available data. Starting from the proposed ART framework, we will discuss several specific instantiations and validate them on both benchmark and real world healthcare data. Our results show that with the ART framework, the patients can be efficiently and effectively indexed in the sense that (1) similarity patients can be retrieved in a very short time; (2) the retrieval performance can beat the state-of-the art indexing methods. Copyright © 2015. Published by Elsevier Inc.

LSG: An External-Memory Tool to Compute String Graphs for Next-Generation Sequencing Data Assembly.

PubMed

Bonizzoni, Paola; Vedova, Gianluca Della; Pirola, Yuri; Previtali, Marco; Rizzi, Raffaella

2016-03-01

The large amount of short read data that has to be assembled in future applications, such as in metagenomics or cancer genomics, strongly motivates the investigation of disk-based approaches to index next-generation sequencing (NGS) data. Positive results in this direction stimulate the investigation of efficient external memory algorithms for de novo assembly from NGS data. Our article is also motivated by the open problem of designing a space-efficient algorithm to compute a string graph using an indexing procedure based on the Burrows-Wheeler transform (BWT). We have developed a disk-based algorithm for computing string graphs in external memory: the light string graph (LSG). LSG relies on a new representation of the FM-index that is exploited to use an amount of main memory requirement that is independent from the size of the data set. Moreover, we have developed a pipeline for genome assembly from NGS data that integrates LSG with the assembly step of SGA (Simpson and Durbin, 2012 ), a state-of-the-art string graph-based assembler, and uses BEETL for indexing the input data. LSG is open source software and is available online. We have analyzed our implementation on a 875-million read whole-genome dataset, on which LSG has built the string graph using only 1GB of main memory (reducing the memory occupation by a factor of 50 with respect to SGA), while requiring slightly more than twice the time than SGA. The analysis of the entire pipeline shows an important decrease in memory usage, while managing to have only a moderate increase in the running time.

Can a canopy temperature-based stress index enhance water use efficiency in irrigated wine grape under arid conditions?

USDA-ARS?s Scientific Manuscript database

Enhancement of irrigation water use efficiency and water productivity in arid wine grape production regions is hindered by a lack of automated, real-time methods for monitoring and interpreting vine water status. A normalized, water stress index calculated from real-time vine canopy temperature meas...

[Optimization of Formulation and Process of Paclitaxel PEGylated Liposomes by Box-Behnken Response Surface Methodology].

PubMed

Shi, Ya-jun; Zhang, Xiao-feil; Guo, Qiu-ting

2015-12-01

To develop a procedure for preparing paclitaxel encapsulated PEGylated liposomes. The membrane hydration followed extraction method was used to prepare PEGylated liposomes. The process and formulation variables were optimized by "Box-Behnken Design (BBD)" of response surface methodology (RSM) with the amount of Soya phosphotidylcholine (SPC) and PEG2000-DSPE as well as the rate of SPC to drug as independent variables and entrapment efficiency as dependent variables for optimization of formulation variables while temperature, pressure and cycle times as independent variables and particle size and polydispersion index as dependent variables for process variables. The optimized liposomal formulation was characterized for particle size, Zeta potential, morphology and in vitro drug release. For entrapment efficiency, particle size, polydispersion index, Zeta potential, and in vitro drug release of PEGylated liposomes was found to be 80.3%, (97.15 ± 14.9) nm, 0.117 ± 0.019, (-30.3 ± 3.7) mV, and 37.4% in 24 h, respectively. The liposomes were found to be small, unilamellar and spherical with smooth surface as seen in transmission electron microscopy. The Box-Behnken response surface methodology facilitates the formulation and optimization of paclitaxel PEGylated liposomes.

Echo™ User Manual

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

Harvey, Dustin Yewell

Echo™ is a MATLAB-based software package designed for robust and scalable analysis of complex data workflows. An alternative to tedious, error-prone conventional processes, Echo is based on three transformative principles for data analysis: self-describing data, name-based indexing, and dynamic resource allocation. The software takes an object-oriented approach to data analysis, intimately connecting measurement data with associated metadata. Echo operations in an analysis workflow automatically track and merge metadata and computation parameters to provide a complete history of the process used to generate final results, while automated figure and report generation tools eliminate the potential to mislabel those results. History reportingmore » and visualization methods provide straightforward auditability of analysis processes. Furthermore, name-based indexing on metadata greatly improves code readability for analyst collaboration and reduces opportunities for errors to occur. Echo efficiently manages large data sets using a framework that seamlessly allocates resources such that only the necessary computations to produce a given result are executed. Echo provides a versatile and extensible framework, allowing advanced users to add their own tools and data classes tailored to their own specific needs. Applying these transformative principles and powerful features, Echo greatly improves analyst efficiency and quality of results in many application areas.« less

Mismatch Considerations in Excitation of Single-Mode Circular Core Parabolic Index Fiber by Laser Diode via Upside Down Tapered Hemispherical Microlens on the Tip of the Fiber

NASA Astrophysics Data System (ADS)

Das, Bishuddhananda; Middya, Tapas Ranjan; Gangopadhyay, Sankar

2017-12-01

We report the theoretical investigation of the coupling optics involving laser diode to single-mode circular core parabolic index fiber via upside down tapered hemispherical microlens on the tip of the fiber in the presence of possible transverse and angular mismatches. Using the relevant ABCD matrix for such tapered hemispherical microlens, we formulate analytical expressions for the coupling efficiencies in the presence of the said two mismatches. Further, the transmitted spot size of the source via the hemispherical lens and the tapered region should match with the spot size of the fiber for obtaining maximum coupling. The investigations have been made for two practical wavelengths, namely 1.3 and 1.5 μm in order to find the tolerance of this coupling device with respect to the said kinds of mismatches at the concerned wavelengths. Although our simple method predicts the concerned coupling optics excellently, the evaluation of the concerned efficiencies and associated losses involve little computations. Thus this user-friendly technique and also the results found thereof will benefit the designers and packagers who are working in the field of optical technology.

Internet-Delivered Cognitive Behavioral Therapy to Treat Insomnia: A Systematic Review and Meta-Analysis.

PubMed

Seyffert, Michael; Lagisetty, Pooja; Landgraf, Jessica; Chopra, Vineet; Pfeiffer, Paul N; Conte, Marisa L; Rogers, Mary A M

2016-01-01

Insomnia is of major public health importance. While cognitive behavioral therapy is beneficial, in-person treatment is often unavailable. We assessed the effectiveness of internet-delivered cognitive behavioral therapy for insomnia. The primary objectives were to determine whether online cognitive behavioral therapy for insomnia could improve sleep efficiency and reduce the severity of insomnia in adults. Secondary outcomes included sleep quality, total sleep time, time in bed, sleep onset latency, wake time after sleep onset, and number of nocturnal awakenings. We searched PubMed/MEDLINE, the Cumulative Index to Nursing and Allied Health Literature, PsycInfo, Cochrane Library, Embase, and the Web of Science for randomized trials. Studies were eligible if they were randomized controlled trials in adults that reported application of cognitive behavioral therapy for insomnia via internet delivery. Mean differences in improvement in sleep measures were calculated using the Hartung-Knapp-Sidik-Jonkman method for random effects meta-analysis. We found 15 trials, all utilizing a pretest-posttest randomized control group design. Sleep efficiency was 72% at baseline and improved by 7.2% (95% CI: 5.1%, 9.3%; p<0.001) with internet-delivered cognitive behavioral therapy versus control. Internet-delivered cognitive behavioral therapy resulted in a decrease in the insomnia severity index by 4.3 points (95% CI: -7.1, -1.5; p = 0.017) compared to control. Total sleep time averaged 5.7 hours at baseline and increased by 20 minutes with internet-delivered therapy versus control (95% CI: 9, 31; p = 0.004). The severity of depression decreased by 2.3 points (95% CI: -2.9, -1.7; p = 0.013) in individuals who received internet-delivered cognitive behavioral therapy compared to control. Improvements in sleep efficiency, the insomnia severity index and depression scores with internet-delivered cognitive behavioral therapy were maintained from 4 to 48 weeks after post-treatment assessment. There were no statistically significant differences between sleep efficiency, total sleep time, and insomnia severity index for internet-delivered versus in-person therapy with a trained therapist. In conclusion, internet-delivered cognitive behavioral therapy is effective in improving sleep in adults with insomnia. Efforts should be made to educate the public and expand access to this therapy. Registration Number, Prospero: CRD42015017622.

Internet-Delivered Cognitive Behavioral Therapy to Treat Insomnia: A Systematic Review and Meta-Analysis

PubMed Central

Seyffert, Michael; Lagisetty, Pooja; Landgraf, Jessica; Chopra, Vineet; Pfeiffer, Paul N.; Conte, Marisa L.; Rogers, Mary A. M.

2016-01-01

Background Insomnia is of major public health importance. While cognitive behavioral therapy is beneficial, in-person treatment is often unavailable. We assessed the effectiveness of internet-delivered cognitive behavioral therapy for insomnia. Objectives The primary objectives were to determine whether online cognitive behavioral therapy for insomnia could improve sleep efficiency and reduce the severity of insomnia in adults. Secondary outcomes included sleep quality, total sleep time, time in bed, sleep onset latency, wake time after sleep onset, and number of nocturnal awakenings. Data Sources We searched PubMed/MEDLINE, the Cumulative Index to Nursing and Allied Health Literature, PsycInfo, Cochrane Library, Embase, and the Web of Science for randomized trials. Methods Studies were eligible if they were randomized controlled trials in adults that reported application of cognitive behavioral therapy for insomnia via internet delivery. Mean differences in improvement in sleep measures were calculated using the Hartung-Knapp-Sidik-Jonkman method for random effects meta-analysis. Results We found 15 trials, all utilizing a pretest-posttest randomized control group design. Sleep efficiency was 72% at baseline and improved by 7.2% (95% CI: 5.1%, 9.3%; p<0.001) with internet-delivered cognitive behavioral therapy versus control. Internet-delivered cognitive behavioral therapy resulted in a decrease in the insomnia severity index by 4.3 points (95% CI: -7.1, -1.5; p = 0.017) compared to control. Total sleep time averaged 5.7 hours at baseline and increased by 20 minutes with internet-delivered therapy versus control (95% CI: 9, 31; p = 0.004). The severity of depression decreased by 2.3 points (95% CI: -2.9, -1.7; p = 0.013) in individuals who received internet-delivered cognitive behavioral therapy compared to control. Improvements in sleep efficiency, the insomnia severity index and depression scores with internet-delivered cognitive behavioral therapy were maintained from 4 to 48 weeks after post-treatment assessment. There were no statistically significant differences between sleep efficiency, total sleep time, and insomnia severity index for internet-delivered versus in-person therapy with a trained therapist. Conclusion In conclusion, internet-delivered cognitive behavioral therapy is effective in improving sleep in adults with insomnia. Efforts should be made to educate the public and expand access to this therapy. Registration Number, Prospero: CRD42015017622 PMID:26867139

Deficiency in clonogenic endometrial mesenchymal stem cells in obese women with reproductive failure--a pilot study.

PubMed

Murakami, Keisuke; Bhandari, Harish; Lucas, Emma S; Takeda, Satoru; Gargett, Caroline E; Quenby, Siobhan; Brosens, Jan J; Tan, Bee K

2013-01-01

The mechanisms of obesity associated reproductive complications remain poorly understood. Endometrial mesenchymal stem-cells are critical for cyclic renewal and uterine function. Recently, W5C5(+) cells, with high clonogenicity, capable of producing endometrial stroma in vivo, have been described. We sought to investigate the abundance and cloning efficiency of W5C5(+) and W5C5(-) endometrial cells in relation to Body Mass Index, age and reproductive outcome. W5C5(+) and W5C5(-) cells were purified from mid-luteal endometrial biopsies (n = 54) by magnetic bead separation and subjected to in vitro colony-forming assays. First trimester pregnancy losses were significantly higher in obese subjects (n = 12) compared to overweight (n = 20) and subjects with normal Body Mass Index (n = 22) (P<0.05, P<0.01, respectively). W5C5(+) cells (%) were significantly lower in obese subjects compared to subjects with normal Body Mass Index (P<0.05). W5C5(+) cloning efficiency was significantly lower in obese subjects compared to overweight and subjects with normal Body Mass Index (P<0.05, respectively). W5C5(-) cloning efficiency was significantly lower in obese subjects compared to subjects with normal Body Mass Index (P<0.05). Body Mass Index was significantly negatively correlated with W5C5(+) cloning efficiency and W5C5(-) cloning efficiency (P<0.01, respectively), and positively correlated with first trimester loss (P<0.01). We found no significant results with age (P>0.05). Our observations suggest that the regenerative capacity and plasticity of the endometrium of obese women is suboptimal, which in turn may account for the increased risk of reproductive complications associated with obesity.

A novel hybrid algorithm for the design of the phase diffractive optical elements for beam shaping

NASA Astrophysics Data System (ADS)

Jiang, Wenbo; Wang, Jun; Dong, Xiucheng

2013-02-01

In this paper, a novel hybrid algorithm for the design of a phase diffractive optical elements (PDOE) is proposed. It combines the genetic algorithm (GA) with the transformable scale BFGS (Broyden, Fletcher, Goldfarb, Shanno) algorithm, the penalty function was used in the cost function definition. The novel hybrid algorithm has the global merits of the genetic algorithm as well as the local improvement capabilities of the transformable scale BFGS algorithm. We designed the PDOE using the conventional simulated annealing algorithm and the novel hybrid algorithm. To compare the performance of two algorithms, three indexes of the diffractive efficiency, uniformity error and the signal-to-noise ratio are considered in numerical simulation. The results show that the novel hybrid algorithm has good convergence property and good stability. As an application example, the PDOE was used for the Gaussian beam shaping; high diffractive efficiency, low uniformity error and high signal-to-noise were obtained. The PDOE can be used for high quality beam shaping such as inertial confinement fusion (ICF), excimer laser lithography, fiber coupling laser diode array, laser welding, etc. It shows wide application value.

Explaining the variability of Photochemical Reflectance Index (PRI): deconvolution of variability related to Light Use Efficiency and Canopy attributes.

NASA Astrophysics Data System (ADS)

Merlier, Elodie; Hmimina, Gabriel; Dufrêne, Eric; Soudani, Kamel

2014-05-01

The Photochemical Reflectance Index (PRI) was designed as a proxy of the state of xanthophyll cycle which is used as a response of plants to excess of light (Gamon et al., 1990; 1992). Strong relationships between PRI and LUE were shown at leaf and canopy scales and over a wide range of species (Garbulsky et al., 2011). However, its use at canopy scale was shown to be significantly hampered by effects of confounding factors such as the PRI sensitivity to leaf pigment content (Gamon et al. 2001; Nakaji et al. 2006) and to canopy structure (Hilker et al. 2008). Several approaches aimed at correcting such effects and recent works focused on the deconvolution of LUE related and LUE unrelated PRI variability (Rahimzadeh-Bajgiran et al. 2012).In this study, the PRI variability at canopy scale is investigated over two years on three species (Fagus sylvatica, Quercus robur and Pinus sylvestris) growing under two water regimes. At daily scale, PRI variability is mainly explained by radiation conditions. As already reported at leaf scale in Hmimina et al. (2014), analysis of PRI responses to incoming photosynthetically active radiation over seasonal scale allowed to separate two sources of variability : a constitutive variability mainly related to canopy structure and leaf chlorophyll content and a facultative variability mainly related to LUE and soil moisture content. These results highlight the composite nature of PRI signal measured at canopy scale and the importance of disentangling its sources of variability in order to accurately assess ecosystem light use efficiency. Gamon JA, Field CB, Bilger W, Björkman O, Fredeen AL, Peñuelas J. 1990. Remote sensing of the xanthophyll cycle and chlorophyll fluorescence in sunflower leaves and canopies. Oecologia 85, 1-7. Gamon JA, Field CB, Fredeen A AL, Thayer S. 2001. Assessing photosynthetic downregulation in sunflower stands with an optically-based model. Photosynthesis Research 67, 113-125. Gamon JA, Peñuelas J, Field CB. 1992. A narrow-waveband spectral index that tracks diurnal changes in photosynthetic efficiency. Remote Sensing of Environment 41, 35-44. Garbulsky MF, Peñuelas J, Gamon J, Inoue Y, Filella I. 2011. The photochemical reflectance index (PRI) and the remote sensing of leaf, canopy and ecosystem radiation use efficiencies: A review and meta-analysis. Remote Sensing of Environment 115, 281-297. Hilker T, Coops NC, Hall FG, Black TA, Wulder MA, Nesic Z, Krishnan P. 2008. Separating physiologically and directionally induced changes in PRI using BRDF models. Remote Sensing of Environment 112, 2777-2788. Hmimina G, Dufrêne E, Soudani K. 2014. Relationship between PRI and leaf ecophysiological and biochemical parameters under two different water statuses: toward a rapid and efficient correction method using real-time measurements. Plant, Cell & Environment 37, 2, 473-487. Nakaji T, Oguma H, Fujinuma Y. 2006. Seasonal changes in the relationship between photochemical reflectance index and photosynthetic light use efficiency of Japanese larch needles. International Journal of Remote Sensing 27, 493-509. Rahimzadeh-Bajgiran P, Munehiro M, Omasa K. 2012. Relationships between the photochemical reflectance index (PRI) and chlorophyll fluorescence parameters and plant pigment indices at different leaf growth stages. Photosynthesis Research 113, 261-271.

Development of AIM-Based Fast Solver for Efficient Design and Synthesis of Negative Index Materials

DTIC Science & Technology

2007-12-06

N∑ n=1 Dn < fn/ε̂ > = N∑ n=1 Dn [ 1 ε̂+n ∫ T+m fn · fmdv + 1 ε̂−n ∫ T−m fn · fmdv ] (A.34) (Recall that fm, is zero outside of T±m These integrals...the centroid of Tm. The scalar potential term of (A.32) can be written as < ∇Φ,fm >= ∫ S Φfm · n̂ds− ∫ V Φ∇ · fmdv (A.37) where Sis the boundary of V

Human motor transfer is determined by the scaling of size and accuracy of movement.

PubMed

Kwon, Oh-Sang; Zelaznik, Howard N; Chiu, George; Pizlo, Zygmunt

2011-01-01

A transfer of training design was used to examine the role of the Index of Difficulty (ID) on transfer of learning in a sequential Fitts's law task. Specifically, the role of the ratio between the accuracy and size of movement (ID) in transfer was examined. Transfer of skilled movement is better when both the size and accuracy of movement are changed by the same factor (ID is constant) than when only size or accuracy is changed. The authors infer that the size-accuracy ratio is capturing the control strategies employed during practice and thus promotes efficient transfer. Furthermore, efficient transfer is not dependent on maintaining relative timing invariance and thus the authors provide further evidence that relative timing is not an essential feature of movement control.

FPGA implementation of sparse matrix algorithm for information retrieval

NASA Astrophysics Data System (ADS)

Bojanic, Slobodan; Jevtic, Ruzica; Nieto-Taladriz, Octavio

2005-06-01

Information text data retrieval requires a tremendous amount of processing time because of the size of the data and the complexity of information retrieval algorithms. In this paper the solution to this problem is proposed via hardware supported information retrieval algorithms. Reconfigurable computing may adopt frequent hardware modifications through its tailorable hardware and exploits parallelism for a given application through reconfigurable and flexible hardware units. The degree of the parallelism can be tuned for data. In this work we implemented standard BLAS (basic linear algebra subprogram) sparse matrix algorithm named Compressed Sparse Row (CSR) that is showed to be more efficient in terms of storage space requirement and query-processing timing over the other sparse matrix algorithms for information retrieval application. Although inverted index algorithm is treated as the de facto standard for information retrieval for years, an alternative approach to store the index of text collection in a sparse matrix structure gains more attention. This approach performs query processing using sparse matrix-vector multiplication and due to parallelization achieves a substantial efficiency over the sequential inverted index. The parallel implementations of information retrieval kernel are presented in this work targeting the Virtex II Field Programmable Gate Arrays (FPGAs) board from Xilinx. A recent development in scientific applications is the use of FPGA to achieve high performance results. Computational results are compared to implementations on other platforms. The design achieves a high level of parallelism for the overall function while retaining highly optimised hardware within processing unit.

Analytic energy gradients for the coupled-cluster singles and doubles method with the density-fitting approximation

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

Bozkaya, Uğur, E-mail: ugur.bozkaya@hacettepe.edu.tr; Department of Chemistry, Atatürk University, Erzurum 25240; Sherrill, C. David

2016-05-07

An efficient implementation is presented for analytic gradients of the coupled-cluster singles and doubles (CCSD) method with the density-fitting approximation, denoted DF-CCSD. Frozen core terms are also included. When applied to a set of alkanes, the DF-CCSD analytic gradients are significantly accelerated compared to conventional CCSD for larger molecules. The efficiency of our DF-CCSD algorithm arises from the acceleration of several different terms, which are designated as the “gradient terms”: computation of particle density matrices (PDMs), generalized Fock-matrix (GFM), solution of the Z-vector equation, formation of the relaxed PDMs and GFM, back-transformation of PDMs and GFM to the atomic orbitalmore » (AO) basis, and evaluation of gradients in the AO basis. For the largest member of the alkane set (C{sub 10}H{sub 22}), the computational times for the gradient terms (with the cc-pVTZ basis set) are 2582.6 (CCSD) and 310.7 (DF-CCSD) min, respectively, a speed up of more than 8-folds. For gradient related terms, the DF approach avoids the usage of four-index electron repulsion integrals. Based on our previous study [U. Bozkaya, J. Chem. Phys. 141, 124108 (2014)], our formalism completely avoids construction or storage of the 4-index two-particle density matrix (TPDM), using instead 2- and 3-index TPDMs. The DF approach introduces negligible errors for equilibrium bond lengths and harmonic vibrational frequencies.« less

Optimal Embedding for Shape Indexing in Medical Image Databases

PubMed Central

Qian, Xiaoning; Tagare, Hemant D.; Fulbright, Robert K.; Long, Rodney; Antani, Sameer

2010-01-01

This paper addresses the problem of indexing shapes in medical image databases. Shapes of organs are often indicative of disease, making shape similarity queries important in medical image databases. Mathematically, shapes with landmarks belong to shape spaces which are curved manifolds with a well defined metric. The challenge in shape indexing is to index data in such curved spaces. One natural indexing scheme is to use metric trees, but metric trees are prone to inefficiency. This paper proposes a more efficient alternative. We show that it is possible to optimally embed finite sets of shapes in shape space into a Euclidean space. After embedding, classical coordinate-based trees can be used for efficient shape retrieval. The embedding proposed in the paper is optimal in the sense that it least distorts the partial Procrustes shape distance. The proposed indexing technique is used to retrieve images by vertebral shape from the NHANES II database of cervical and lumbar spine x-ray images maintained at the National Library of Medicine. Vertebral shape strongly correlates with the presence of osteophytes, and shape similarity retrieval is proposed as a tool for retrieval by osteophyte presence and severity. Experimental results included in the paper evaluate (1) the usefulness of shape-similarity as a proxy for osteophytes, (2) the computational and disk access efficiency of the new indexing scheme, (3) the relative performance of indexing with embedding to the performance of indexing without embedding, and (4) the computational cost of indexing using the proposed embedding versus the cost of an alternate embedding. The experimental results clearly show the relevance of shape indexing and the advantage of using the proposed embedding. PMID:20163981

Optimal embedding for shape indexing in medical image databases.

PubMed

Qian, Xiaoning; Tagare, Hemant D; Fulbright, Robert K; Long, Rodney; Antani, Sameer

2010-06-01

This paper addresses the problem of indexing shapes in medical image databases. Shapes of organs are often indicative of disease, making shape similarity queries important in medical image databases. Mathematically, shapes with landmarks belong to shape spaces which are curved manifolds with a well defined metric. The challenge in shape indexing is to index data in such curved spaces. One natural indexing scheme is to use metric trees, but metric trees are prone to inefficiency. This paper proposes a more efficient alternative. We show that it is possible to optimally embed finite sets of shapes in shape space into a Euclidean space. After embedding, classical coordinate-based trees can be used for efficient shape retrieval. The embedding proposed in the paper is optimal in the sense that it least distorts the partial Procrustes shape distance. The proposed indexing technique is used to retrieve images by vertebral shape from the NHANES II database of cervical and lumbar spine X-ray images maintained at the National Library of Medicine. Vertebral shape strongly correlates with the presence of osteophytes, and shape similarity retrieval is proposed as a tool for retrieval by osteophyte presence and severity. Experimental results included in the paper evaluate (1) the usefulness of shape similarity as a proxy for osteophytes, (2) the computational and disk access efficiency of the new indexing scheme, (3) the relative performance of indexing with embedding to the performance of indexing without embedding, and (4) the computational cost of indexing using the proposed embedding versus the cost of an alternate embedding. The experimental results clearly show the relevance of shape indexing and the advantage of using the proposed embedding. Copyright (c) 2010 Elsevier B.V. All rights reserved.

Computer Supported Indexing: A History and Evaluation of NASA's MAI System. Supplement 24

NASA Technical Reports Server (NTRS)

Silvester, June P.

1997-01-01

Computer supported indexing systems may be categorized in several ways. One classification scheme refers to them as statistical, syntactic, semantic or knowledge-based. While a system may emphasize one of these aspects, most systems actually combine two or more of these mechanisms to maximize system efficiency. Statistical systems can be based on counts of words or word stems, statistical association, and correlation techniques that assign weights to word locations or provide lexical disambiguation, calculations regarding the likelihood of word co-occurrences, clustering of word stems and transformations, or any other computational method used to identify pertinent terms. If words are counted, the ones of median frequency become candidate index terms. Syntactical systems stress grammar and identify parts of speech. Concepts found in designated grammatical combinations, such as noun phrases, generate the suggested terms. Semantic systems are concerned with the context sensitivity of words in text. The primary goal of this type of indexing is to identify without regard to syntax the subject matter and the context-bearing words in the text being indexed. Knowledge-based systems provide a conceptual network that goes past thesaurus or equivalent relationships to knowing (e.g., in the National Library of Medicine (NLM) system) that because the tibia is part of the leg, a document relating to injuries to the tibia should he indexed to LEG INJURIES, not the broader MeSH term INJURIES, or knowing that the term FEMALE should automatically be added when the term PREGNANCY is assigned, and also that the indexer should be prompted to add either HUMAN or ANIMAL. Another way of categorizing indexing systems is to identify them as producing either assigned- or derived-term indexes.

Design and Evaluation of Microemulsion Gel System of Nadifloxacin

PubMed Central

Shinde, Ujwala; Pokharkar, Sharda; Modani, Sheela

2012-01-01

Topical microemulsion systems for the antiacne agent, nadifloxacin were designed and developed to overcome the problems associated with the cutaneous delivery due to poor water solubility. The solubility of nadifloxacin in oils, surfactants and cosurfactants was evaluated to screen the components of the microemulsion. Various surfactants and cosurfactants were screened for their ability to emulsify the selected oily phase. The pseudoternary diagrams were constructed to identify the area of microemulsion existence. The influence of km (surfactant/cosurfactant) ratio on the microemulsion existence region was determined and optimum systems were designed. The systems were assessed for drug-loading efficiency and characterised for optical birefringence, pH and refractive index, robustness to dilution, globule size, drug content and thermodynamic stability. Optimised microemulsion systems were formulated into gel form and evaluated for viscosity, spreadability, drug content, ex vivo skin permeation and antibacterial activity. The maximum solubility of nadifloxacin in the microemulsion system was found to be 0.25%. The nadifloxacin microemulsions had a small and uniform globule size (67.3-121.23 nm). The stability results revealed that all formulations showed a stable globule size and the polydispersity index under stress conditions. Incorporation of nadifloxacin in microemulsion gel increased the ex vivo skin permeation and antibacterial activity when compared to marketed cream. PMID:23439454

Maximizing Efficiency and Reducing Robotic Surgery Costs Using the NASA Task Load Index.

PubMed

Walters, Carrie; Webb, Paula J

2017-10-01

Perioperative leaders at our facility were struggling to meet efficiency targets for robotic surgery procedures while also maintaining the satisfaction of the surgical team. We developed a human resources time and motion study tool and used it in conjunction with the NASA Task Load Index to observe and analyze the required workload of personnel assigned to 25 robotic surgery procedures. The time and motion study identified opportunities to enlist the help of nonlicensed support personnel to ensure safe patient care and improve OR efficiency. Using the NASA Task Load Index demonstrated that high temporal, effort, and physical demands existed for personnel assisting with and performing robotic surgery. We believe that this process could be used to develop cost-effective staffing models, resulting in safe and efficient care for all surgical patients. Copyright © 2017 AORN, Inc. Published by Elsevier Inc. All rights reserved.

Chromatographic efficiency of polar capillary columns applied for the analysis of fatty acid methyl esters by gas chromatography.

PubMed

Waktola, Habtewold D; Mjøs, Svein A

2018-04-01

The chromatographic efficiency that could be achieved in temperature-programmed gas chromatography was compared for four capillary columns that are typically applied for analysis of fatty acid methyl esters (FAME). Three different carrier gases, hydrogen, helium and nitrogen, were applied. For each experiment, the carrier gas velocities and the temperature rates were varied with a full 9 × 3 design, with nine levels on the carrier gas velocity and temperature rates of 1, 2 or 3°C/min. Response surface methodology was used to create models of chromatographic efficiency as a function of temperature rate and carrier gas velocity. The chromatographic efficiency was defined as the inverse of peak widths measured in retention index units. The final results were standardized so that the efficiencies that could be achieved within a certain time frame, defined by the retention time of the last compound in the chromatogram, could be compared. The results show that there were clear differences in the efficiencies that could be achieved with the different columns and that the efficiency decreased with increasing polarity of the stationary phase. The differences can be explained by higher resistance to mass transfer in the stationary phase in the most polar columns. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Content-Aware DataGuide with Incremental Index Update using Frequently Used Paths

NASA Astrophysics Data System (ADS)

Sharma, A. K.; Duhan, Neelam; Khattar, Priyanka

2010-11-01

Size of the WWW is increasing day by day. Due to the absence of structured data on the Web, it becomes very difficult for information retrieval tools to fully utilize the Web information. As a solution to this problem, XML pages come into play, which provide structural information to the users to some extent. Without efficient indexes, query processing can be quite inefficient due to an exhaustive traversal on XML data. In this paper an improved content-centric approach of Content-Aware DataGuide, which is an indexing technique for XML databases, is being proposed that uses frequently used paths from historical query logs to improve query performance. The index can be updated incrementally according to the changes in query workload and thus, the overhead of reconstruction can be minimized. Frequently used paths are extracted using any Sequential Pattern mining algorithm on subsequent queries in the query workload. After this, the data structures are incrementally updated. This indexing technique proves to be efficient as partial matching queries can be executed efficiently and users can now get the more relevant documents in results.

Automatic design of fiber-reinforced soft actuators for trajectory matching

NASA Astrophysics Data System (ADS)

Connolly, Fionnuala; Walsh, Conor J.; Bertoldi, Katia

2017-01-01

Soft actuators are the components responsible for producing motion in soft robots. Although soft actuators have allowed for a variety of innovative applications, there is a need for design tools that can help to efficiently and systematically design actuators for particular functions. Mathematical modeling of soft actuators is an area that is still in its infancy but has the potential to provide quantitative insights into the response of the actuators. These insights can be used to guide actuator design, thus accelerating the design process. Here, we study fluid-powered fiber-reinforced actuators, because these have previously been shown to be capable of producing a wide range of motions. We present a design strategy that takes a kinematic trajectory as its input and uses analytical modeling based on nonlinear elasticity and optimization to identify the optimal design parameters for an actuator that will follow this trajectory upon pressurization. We experimentally verify our modeling approach, and finally we demonstrate how the strategy works, by designing actuators that replicate the motion of the index finger and thumb.

Automatic design of fiber-reinforced soft actuators for trajectory matching

PubMed Central

Connolly, Fionnuala; Walsh, Conor J.; Bertoldi, Katia

2017-01-01

Soft actuators are the components responsible for producing motion in soft robots. Although soft actuators have allowed for a variety of innovative applications, there is a need for design tools that can help to efficiently and systematically design actuators for particular functions. Mathematical modeling of soft actuators is an area that is still in its infancy but has the potential to provide quantitative insights into the response of the actuators. These insights can be used to guide actuator design, thus accelerating the design process. Here, we study fluid-powered fiber-reinforced actuators, because these have previously been shown to be capable of producing a wide range of motions. We present a design strategy that takes a kinematic trajectory as its input and uses analytical modeling based on nonlinear elasticity and optimization to identify the optimal design parameters for an actuator that will follow this trajectory upon pressurization. We experimentally verify our modeling approach, and finally we demonstrate how the strategy works, by designing actuators that replicate the motion of the index finger and thumb. PMID:27994133

Automatic design of fiber-reinforced soft actuators for trajectory matching.

PubMed

Connolly, Fionnuala; Walsh, Conor J; Bertoldi, Katia

2017-01-03

Soft actuators are the components responsible for producing motion in soft robots. Although soft actuators have allowed for a variety of innovative applications, there is a need for design tools that can help to efficiently and systematically design actuators for particular functions. Mathematical modeling of soft actuators is an area that is still in its infancy but has the potential to provide quantitative insights into the response of the actuators. These insights can be used to guide actuator design, thus accelerating the design process. Here, we study fluid-powered fiber-reinforced actuators, because these have previously been shown to be capable of producing a wide range of motions. We present a design strategy that takes a kinematic trajectory as its input and uses analytical modeling based on nonlinear elasticity and optimization to identify the optimal design parameters for an actuator that will follow this trajectory upon pressurization. We experimentally verify our modeling approach, and finally we demonstrate how the strategy works, by designing actuators that replicate the motion of the index finger and thumb.

High slope efficiency and high refractive index change in direct-written Yb-doped waveguide lasers with depressed claddings.

PubMed

Palmer, Guido; Gross, Simon; Fuerbach, Alexander; Lancaster, David G; Withford, Michael J

2013-07-15

We report the first Yb:ZBLAN and Yb:IOG10 waveguide lasers fabricated by the fs-laser direct-writing technique. Pulses from a Titanium-Sapphire laser oscillator with 5.1 MHz repetition rate were utilized to generate negative refractive index modifications in both glasses. Multiple modifications were aligned in a depressed cladding geometry to create a waveguide. For Yb:ZBLAN we demonstrate high laser slope efficiency of 84% with a maximum output power of 170 mW. By using Yb:IOG10 a laser performance of 25% slope efficiency and 72 mW output power was achieved and we measured a remarkably high refractive index change exceeding Δn = 2.3 × 10(-2).

Design of a 50/50 splitting ratio non-polarizing beam splitter based on the modal method with fused-silica transmission gratings

NASA Astrophysics Data System (ADS)

Zhao, Huajun; Yuan, Dairong; Ming, Hai

2011-04-01

The optical design of a beam splitter that has a 50/50 splitting ratio regardless of the polarization is presented. The non-polarizing beam splitter (NPBS) is based on the fused-silica rectangular transmission gratings with high intensity tolerance. The modal method has been used to estimate the effective index of the modes excited in the grating region for TE and TM polarizations. If a phase difference equals an odd multiples of π/2 for the first two modes (i.e. modes 0 and 1), the incident light will be diffracted into the 0 and -1 orders with about 50% and 50% diffraction efficiency for TM and TE polarizations, respectively.

Construction of road network vulnerability evaluation index based on general travel cost

NASA Astrophysics Data System (ADS)

Leng, Jun-qiang; Zhai, Jing; Li, Qian-wen; Zhao, Lin

2018-03-01

With the development of China's economy and the continuous improvement of her urban road network, the vulnerability of the urban road network has attracted increasing attention. Based on general travel cost, this work constructs the vulnerability evaluation index for the urban road network, and evaluates the vulnerability of the urban road network from the perspective of user generalised travel cost. Firstly, the generalised travel cost model is constructed based on vehicle cost, travel time, and traveller comfort. Then, the network efficiency index is selected as an evaluation index of vulnerability: the network efficiency index is composed of the traffic volume and the generalised travel cost, which are obtained from the equilibrium state of the network. In addition, the research analyses the influence of traffic capacity decrease, road section attribute value, and location of road section, on vulnerability. Finally, the vulnerability index is used to analyse the local area network of Harbin and verify its applicability.

Efficiency of a Malaria Reactive Test-and-Treat Program in Southern Zambia: A Prospective, Observational Study.

PubMed

Deutsch-Feldman, Molly; Hamapumbu, Harry; Lubinda, Jailos; Musonda, Michael; Katowa, Ben; Searle, Kelly M; Kobayashi, Tamaki; Shields, Timothy M; Stevenson, Jennifer C; Thuma, Philip E; Moss, William J; For The Southern Africa International Centers Of Excellence For Malaria Research

2018-05-01

To improve malaria surveillance and achieve elimination, the Zambian National Malaria Elimination Program implemented a reactive test-and-treat program in Southern Province in 2013 in which individuals with rapid diagnostic test (RDT)-confirmed malaria are followed-up at their home within 1 week of diagnosis. Individuals present at the index case household and those residing within 140 m of the index case are tested with an RDT and treated with artemether-lumefantrine if positive. This study evaluated the efficiency of this reactive test-and-treat strategy by characterizing infected individuals missed by the RDT and the current screening radius. The radius was expanded to 250 m, and a quantitative polymerase chain reaction (qPCR) test was performed on dried blood spot specimens. From January 2015 through March 2016, 145 index cases were identified at health centers and health posts. A total of 3,333 individuals residing in 525 households were screened. Excluding index cases, the parasite prevalence was 1.1% by RDT (33 positives of 3,016 participants) and 2.4% by qPCR (73 positives of 3,016 participants). Of the qPCR-positive cases, 62% of 73 individuals tested negative by RDT. Approximately half of the infected individuals resided within the index case household (58% of RDT-positive individuals and 48% of qPCR-positive individuals). The low sensitivity of the RDT and the high proportion of secondary cases within the index case household decreased the efficiency of this reactive test-and-treat strategy. Reactive focal drug administration in index case households would be a more efficient approach to treating infected individuals associated with a symptomatic case.

L-shaped fiber-chip grating couplers with high directionality and low reflectivity fabricated with deep-UV lithography.

PubMed

Benedikovic, Daniel; Alonso-Ramos, Carlos; Pérez-Galacho, Diego; Guerber, Sylvain; Vakarin, Vladyslav; Marcaud, Guillaume; Le Roux, Xavier; Cassan, Eric; Marris-Morini, Delphine; Cheben, Pavel; Boeuf, Frédéric; Baudot, Charles; Vivien, Laurent

2017-09-01

Grating couplers enable position-friendly interfacing of silicon chips by optical fibers. The conventional coupler designs call upon comparatively complex architectures to afford efficient light coupling to sub-micron silicon-on-insulator (SOI) waveguides. Conversely, the blazing effect in double-etched gratings provides high coupling efficiency with reduced fabrication intricacy. In this Letter, we demonstrate for the first time, to the best of our knowledge, the realization of an ultra-directional L-shaped grating coupler, seamlessly fabricated by using 193 nm deep-ultraviolet (deep-UV) lithography. We also include a subwavelength index engineered waveguide-to-grating transition that provides an eight-fold reduction of the grating reflectivity, down to 1% (-20  dB). A measured coupling efficiency of -2.7  dB (54%) is achieved, with a bandwidth of 62 nm. These results open promising prospects for the implementation of efficient, robust, and cost-effective coupling interfaces for sub-micrometric SOI waveguides, as desired for large-volume applications in silicon photonics.

Waveguide-loaded silica fibers for coupling to high-index micro-resonators

NASA Astrophysics Data System (ADS)

Latawiec, P.; Burek, M. J.; Venkataraman, V.; Lončar, M.

2016-01-01

Tapered silica fibers are often used to rapidly probe the optical properties of micro-resonators. However, their low refractive index precludes phase-matching when coupling to high-index micro-resonators, reducing efficiency. Here, we demonstrate efficient optical coupling from tapered fibers to high-index micro-resonators by loading the fibers with an ancillary adiabatic waveguide-coupler fabricated via angled-etching. We demonstrate greatly enhanced coupling to a silicon multimode micro-resonator when compared to coupling via the bare fiber only. Signatures of resonator optical bistability are observed at high powers. This scheme can be applied to resonators of any size and material, increasing the functional scope of fiber coupling.

Brain waves-based index for workload estimation and mental effort engagement recognition

NASA Astrophysics Data System (ADS)

Zammouri, A.; Chraa-Mesbahi, S.; Ait Moussa, A.; Zerouali, S.; Sahnoun, M.; Tairi, H.; Mahraz, A. M.

2017-10-01

The advent of the communication systems and considering the complexity that some impose in their use, it is necessary to incorporate and equip these systems with a certain intelligence which takes into account the cognitive and mental capacities of the human operator. In this work, we address the issue of estimating the mental effort of an operator according to the cognitive tasks difficulty levels. Based on the Electroencephalogram (EEG) measurements, the proposed approach analyzes the user’s brain activity from different brain regions while performing cognitive tasks with several levels of difficulty. At a first time, we propose a variances comparison-based classifier (VCC) that makes use of the Power Spectral Density (PSD) of the EEG signal. The aim of using such a classifier is to highlight the brain regions that enter into interaction according to the cognitive task difficulty. In a second time, we present and describe a new EEG-based index for the estimation of mental efforts. The designed index is based on information recorded from two EEG channels. Results from the VCC demonstrate that powers of the Theta [4-7 Hz] (θ) and Alpha [8-12 Hz] (α) oscillations decrease while increasing the cognitive task difficulty. These decreases are mainly located in parietal and temporal brain regions. Based on the Kappa coefficients, decisions of the introduced index are compared to those obtained from an existing index. This performance assessment method revealed strong agreements. Hence the efficiency of the introduced index.

A Standardised Abundance Index from Commercial Spotting Data of Southern Bluefin Tuna (Thunnus maccoyii): Random Effects to the Rescue

PubMed Central

Basson, Marinelle; Farley, Jessica H.

2014-01-01

Commercial aerial spotting of surface schools of juvenile southern bluefin tuna (SBT), Thunnus maccoyii, is conducted as part of fishing operations in the Great Australian Bight in summer. This provides the opportunity to efficiently collect large amounts of data on sightings of SBT. The data can potentially be used to construct a time-series index of relative abundance by standardising the data for issues such as weather, spotter ability and ocean conditions. Unlike a statistically designed survey, the commercial spotting is governed by business considerations and fishing operations. The SBT dataset is therefore highly unbalanced with regard to spotters operating in each season. This complicates the standardisation of the data, particularly with regard to interactions between covariates. We show how a generalized additive model with random effects can simplify both the fitting of the model and the construction of an index, while also avoiding the need to leave out strata or interaction terms that are important. The approach is applicable to standardisation of more traditional catch and effort data. PMID:25541730

A standardised abundance index from commercial spotting data of southern bluefin tuna (Thunnus maccoyii): random effects to the rescue.

PubMed

Basson, Marinelle; Farley, Jessica H

2014-01-01

Commercial aerial spotting of surface schools of juvenile southern bluefin tuna (SBT), Thunnus maccoyii, is conducted as part of fishing operations in the Great Australian Bight in summer. This provides the opportunity to efficiently collect large amounts of data on sightings of SBT. The data can potentially be used to construct a time-series index of relative abundance by standardising the data for issues such as weather, spotter ability and ocean conditions. Unlike a statistically designed survey, the commercial spotting is governed by business considerations and fishing operations. The SBT dataset is therefore highly unbalanced with regard to spotters operating in each season. This complicates the standardisation of the data, particularly with regard to interactions between covariates. We show how a generalized additive model with random effects can simplify both the fitting of the model and the construction of an index, while also avoiding the need to leave out strata or interaction terms that are important. The approach is applicable to standardisation of more traditional catch and effort data.

Search Interface Design Using Faceted Indexing for Web Resources.

ERIC Educational Resources Information Center

Devadason, Francis; Intaraksa, Neelawat; Patamawongjariya, Pornprapa; Desai, Kavita

2001-01-01

Describes an experimental system designed to organize and provide access to Web documents using a faceted pre-coordinate indexing system based on the Deep Structure Indexing System (DSIS) derived from POPSI (Postulate based Permuted Subject Indexing) of Bhattacharyya, and the facet analysis and chain indexing system of Ranganathan. (AEF)

Nutrigenetic screening strains of the mulberry silkworm, Bombyx mori, for nutritional efficiency.

PubMed

Ramesha, Chinnaswamy; Lakshmi, Hothur; Kumari, Savarapu Sugnana; Anuradha, Chevva M; Kumar, Chitta Suresh

2012-01-01

The activity of sericulture is declining due the reduction of mulberry production area in sericulture practicing countries lead to adverse effects on silkworm rearing and cocoon production. Screening for nutrigenetic traits in silkworm, Bombyx mori L. (Lepidoptera: Bombycidae) is an essential prerequisite for better understanding and development of nutritionally efficient breeds/hybrids, which show less food consumption with higher efficiency conversion. The aim of this study was to identify nutritionally efficient polyvoltine silkworm strains using the germplasm breeds RMW(2), RMW(3), RMW(4), RMG(3), RMG(1), RMG(4), RMG(5), RMG(6) and APM(1) as the control. The 1(st) day of 5(th) stage silkworm larvae of polyvoltine strains were subjected to standard gravimetric analysis until spinning for three consecutive generations covering 3 different seasons on 19 nutrigenetic traits. Highly significant (p ≤ 0.001) differences were found among all nutrigenetic traits of polyvoltine silkworm strains in the experimental groups. The nutritionally efficient polvoltine silkworm strains were resulted by utilizing nutrition consumption index and efficiency of conversion of ingesta/cocoon traits as the index. Higher nutritional efficiency conversions were found in the polyvoltine silkworm strains on efficiency of conversion of ingesta to cocoon and shell than control. Comparatively smaller consumption index, respiration, metabolic rate with superior relative growth rate, and quantum of food ingesta and digesta requisite per gram of cocoon and shell were found; the lowest amount was in new polyvoltine strains compared to the control. Furthermore, based on the overall nutrigenetic traits utilized as index or 'biomarkers', three polyvoltine silkworm strains (RMG(4), RMW(2), and RMW(3)) were identified as having the potential for nutrition efficiency conversion. The data from the present study advances our knowledge for the development of nutritionally efficient silkworm breeds/hybrids and their effective commercial utilization in the sericulture industry.

Nutrigenetic screening strains of the mulberry silkworm, Bombyx mori, for nutritional efficiency.

PubMed

Chinnaswamy, Ramesha; Lakshmi, Hothur; Kumari, Savarapu S; Anuradha, Chebba M; Kumar, Chitta S

2012-01-01

The activity of sericulture is declining due the reduction of mulberry production area in sericulture practicing countries lead to adverse effects on silkworm rearing and cocoon production. Screening for nutrigenetic traits in silkworm, Bombyx mori L. (Lepidoptera: Bombycidae) is an essential prerequisite for better understanding and development of nutritionally efficient breeds/hybrids, which show less food consumption with higher efficiency conversion. The aim of this study was to identify nutritionally efficient polyvoltine silkworm strains using the germplasm breeds RMW(2), RMW(3), RMW(4), RMG(3), RMG(1), RMG(4), RMG(5), RMG(6) and APM(1) as the control. The 1(st) day of 5(th) stage silkworm larvae of polyvoltine strains were subjected to standard gravimetric analysis until spinning for three consecutive generations covering three different seasons on 19 nutrigenetic traits. Highly significant (p ≤ 0.001) differences were found among all nutrigenetic traits of polyvoltine silkworm strains in the experimental groups. The nutritionally efficient polvoltine silkworm strains were resulted by utilizing nutrition consumption index and efficiency of conversion of ingesta/cocoon traits as the index. Higher nutritional efficiency conversions were found in the polyvoltine silkworm strains on efficiency of conversion of ingesta to cocoon and shell than control. Comparatively smaller consumption index, respiration, metabolic rate with superior relative growth rate, and quantum of food ingesta and digesta requisite per gram of cocoon and shell were shown; the lowest amount was in new polyvoltine strains compared to the control. Furthermore, based on the overall nutrigenetic traits utilized as index or 'biomarkers', three polyvoltine silkworm strains (RMG(4), RMW(2), and RMW(3)) were identified as having the potential for nutrition efficiency conversion. The data from the present study advances our knowledge for the development of nutritionally efficient silkworm breeds/hybrids and their effective commercial utilization in the sericulture industry.

Nutrigenetic Screening Strains of the Mulberry Silkworm, Bombyx mori, for Nutritional Efficiency

PubMed Central

Chinnaswamy, Ramesha; Lakshmi, Hothur; Kumari, Savarapu S.; Anuradha, Chebba M.; Kumar, Chitta S.

2012-01-01

The activity of sericulture is declining due the reduction of mulberry production area in sericulture practicing countries lead to adverse effects on silkworm rearing and cocoon production. Screening for nutrigenetic traits in silkworm, Bombyx mori L. (Lepidoptera: Bombycidae) is an essential prerequisite for better understanding and development of nutritionally efficient breeds/hybrids, which show less food consumption with higher efficiency conversion. The aim of this study was to identify nutritionally efficient polyvoltine silkworm strains using the germplasm breeds RMW2, RMW3, RMW4, RMG3, RMG1, RMG4, RMG5, RMG6 and APM1 as the control. The 1st day of 5th stage silkworm larvae of polyvoltine strains were subjected to standard gravimetric analysis until spinning for three consecutive generations covering three different seasons on 19 nutrigenetic traits. Highly significant (p ≤ 0.001) differences were found among all nutrigenetic traits of polyvoltine silkworm strains in the experimental groups. The nutritionally efficient polvoltine silkworm strains were resulted by utilizing nutrition consumption index and efficiency of conversion of ingesta/cocoon traits as the index. Higher nutritional efficiency conversions were found in the polyvoltine silkworm strains on efficiency of conversion of ingesta to cocoon and shell than control. Comparatively smaller consumption index, respiration, metabolic rate with superior relative growth rate, and quantum of food ingesta and digesta requisite per gram of cocoon and shell were shown; the lowest amount was in new polyvoltine strains compared to the control. Furthermore, based on the overall nutrigenetic traits utilized as index or ‘biomarkers’, three polyvoltine silkworm strains (RMG4, RMW2, and RMW3) were identified as having the potential for nutrition efficiency conversion. The data from the present study advances our knowledge for the development of nutritionally efficient silkworm breeds/hybrids and their effective commercial utilization in the sericulture industry. PMID:22938037

Nutrigenetic Screening Strains of the Mulberry Silkworm, Bombyx mori, for Nutritional Efficiency

PubMed Central

Ramesha, Chinnaswamy; Lakshmi, Hothur; Kumari, Savarapu Sugnana; Anuradha, Chevva M.; Kumar, Chitta Suresh

2012-01-01

The activity of sericulture is declining due the reduction of mulberry production area in sericulture practicing countries lead to adverse effects on silkworm rearing and cocoon production. Screening for nutrigenetic traits in silkworm, Bombyx mori L. (Lepidoptera: Bombycidae) is an essential prerequisite for better understanding and development of nutritionally efficient breeds/hybrids, which show less food consumption with higher efficiency conversion. The aim of this study was to identify nutritionally efficient polyvoltine silkworm strains using the germplasm breeds RMW2, RMW3, RMW4, RMG3, RMG1, RMG4, RMG5, RMG6 and APM1 as the control. The 1st day of 5th stage silkworm larvae of polyvoltine strains were subjected to standard gravimetric analysis until spinning for three consecutive generations covering 3 different seasons on 19 nutrigenetic traits. Highly significant (p ≤ 0.001) differences were found among all nutrigenetic traits of polyvoltine silkworm strains in the experimental groups. The nutritionally efficient polvoltine silkworm strains were resulted by utilizing nutrition consumption index and efficiency of conversion of ingesta/cocoon traits as the index. Higher nutritional efficiency conversions were found in the polyvoltine silkworm strains on efficiency of conversion of ingesta to cocoon and shell than control. Comparatively smaller consumption index, respiration, metabolic rate with superior relative growth rate, and quantum of food ingesta and digesta requisite per gram of cocoon and shell were found; the lowest amount was in new polyvoltine strains compared to the control. Furthermore, based on the overall nutrigenetic traits utilized as index or ‘biomarkers’, three polyvoltine silkworm strains (RMG4, RMW2, and RMW3) were identified as having the potential for nutrition efficiency conversion. The data from the present study advances our knowledge for the development of nutritionally efficient silkworm breeds/hybrids and their effective commercial utilization in the sericulture industry. PMID:22934597

Fiber-chip edge coupler with large mode size for silicon photonic wire waveguides.

PubMed

Papes, Martin; Cheben, Pavel; Benedikovic, Daniel; Schmid, Jens H; Pond, James; Halir, Robert; Ortega-Moñux, Alejandro; Wangüemert-Pérez, Gonzalo; Ye, Winnie N; Xu, Dan-Xia; Janz, Siegfried; Dado, Milan; Vašinek, Vladimír

2016-03-07

Fiber-chip edge couplers are extensively used in integrated optics for coupling of light between planar waveguide circuits and optical fibers. In this work, we report on a new fiber-chip edge coupler concept with large mode size for silicon photonic wire waveguides. The coupler allows direct coupling with conventional cleaved optical fibers with large mode size while circumventing the need for lensed fibers. The coupler is designed for 220 nm silicon-on-insulator (SOI) platform. It exhibits an overall coupling efficiency exceeding 90%, as independently confirmed by 3D Finite-Difference Time-Domain (FDTD) and fully vectorial 3D Eigenmode Expansion (EME) calculations. We present two specific coupler designs, namely for a high numerical aperture single mode optical fiber with 6 µm mode field diameter (MFD) and a standard SMF-28 fiber with 10.4 µm MFD. An important advantage of our coupler concept is the ability to expand the mode at the chip edge without leading to high substrate leakage losses through buried oxide (BOX), which in our design is set to 3 µm. This remarkable feature is achieved by implementing in the SiO 2 upper cladding thin high-index Si 3 N 4 layers. The Si 3 N 4 layers increase the effective refractive index of the upper cladding near the facet. The index is controlled along the taper by subwavelength refractive index engineering to facilitate adiabatic mode transformation to the silicon wire waveguide while the Si-wire waveguide is inversely tapered along the coupler. The mode overlap optimization at the chip facet is carried out with a full vectorial mode solver. The mode transformation along the coupler is studied using 3D-FDTD simulations and with fully-vectorial 3D-EME calculations. The couplers are optimized for operating with transverse electric (TE) polarization and the operating wavelength is centered at 1.55 µm.

[Analysis of the technical efficiency of hospitals in the Spanish National Health Service].

PubMed

Pérez-Romero, Carmen; Ortega-Díaz, M Isabel; Ocaña-Riola, Ricardo; Martín-Martín, José Jesús

To analyse the technical efficiency and productivity of general hospitals in the Spanish National Health Service (NHS) (2010-2012) and identify explanatory hospital and regional variables. 230 NHS hospitals were analysed by data envelopment analysis for overall, technical and scale efficiency, and Malmquist index. The robustness of the analysis is contrasted with alternative input-output models. A fixed effects multilevel cross-sectional linear model was used to analyse the explanatory efficiency variables. The average rate of overall technical efficiency (OTE) was 0.736 in 2012; there was considerable variability by region. Malmquist index (2010-2012) is 1.013. A 23% variability in OTE is attributable to the region in question. Statistically significant exogenous variables (residents per 100 physicians, aging index, average annual income per household, essential public service expenditure and public health expenditure per capita) explain 42% of the OTE variability between hospitals and 64% between regions. The number of residents showed a statistically significant relationship. As regards regions, there is a statistically significant direct linear association between OTE and annual income per capita and essential public service expenditure, and an indirect association with the aging index and annual public health expenditure per capita. The significant room for improvement in the efficiency of hospitals is conditioned by region-specific characteristics, specifically aging, wealth and the public expenditure policies of each one. Copyright © 2016 SESPAS. Publicado por Elsevier España, S.L.U. All rights reserved.

QUENCH: A software package for the determination of quenching curves in Liquid Scintillation counting.

PubMed

Cassette, Philippe

2016-03-01

In Liquid Scintillation Counting (LSC), the scintillating source is part of the measurement system and its detection efficiency varies with the scintillator used, the vial and the volume and the chemistry of the sample. The detection efficiency is generally determined using a quenching curve, describing, for a specific radionuclide, the relationship between a quenching index given by the counter and the detection efficiency. A quenched set of LS standard sources are prepared by adding a quenching agent and the quenching index and detection efficiency are determined for each source. Then a simple formula is fitted to the experimental points to define the quenching curve function. The paper describes a software package specifically devoted to the determination of quenching curves with uncertainties. The experimental measurements are described by their quenching index and detection efficiency with uncertainties on both quantities. Random Gaussian fluctuations of these experimental measurements are sampled and a polynomial or logarithmic function is fitted on each fluctuation by χ(2) minimization. This Monte Carlo procedure is repeated many times and eventually the arithmetic mean and the experimental standard deviation of each parameter are calculated, together with the covariances between these parameters. Using these parameters, the detection efficiency, corresponding to an arbitrary quenching index within the measured range, can be calculated. The associated uncertainty is calculated with the law of propagation of variances, including the covariance terms. Copyright © 2015 Elsevier Ltd. All rights reserved.

Preparation, characterization, and transport of dexamethasone-loaded polymeric nanoparticles across a human placental in vitro model

PubMed Central

Ali, Hazem; Kalashnikova, Irina; White, Mark Andrew; Sherman, Michael; Rytting, Erik

2013-01-01

The purpose of this study was to prepare dexamethasone-loaded polymeric nanoparticles and evaluate their potential for transport across human placenta. Statistical modeling and factorial design was applied to investigate the influence of process parameters on the following nanoparticle characteristics: particle size, polydispersity index, zeta potential, and drug encapsulation efficiency. Dexamethasone and nanoparticle transport was subsequently investigated using the BeWo b30 cell line, an in vitro model of human placental trophoblast cells, which represent the rate-limiting barrier for maternal-fetal transfer. Encapsulation efficiency and drug transport were determined using a validated high performance liquid chromatography method. Nanoparticle morphology and drug encapsulation were further characterized by cryo-transmission electron microscopy and X-ray diffraction, respectively. Nanoparticles prepared from poly(lactic-co-glycolic acid) were spherical, with particle sizes ranging from 140–298 nm, and encapsulation efficiency ranging from 52–89%. Nanoencapsulation enhanced the apparent permeability of dexamethasone from the maternal compartment to the fetal compartment more than 10-fold in this model. Particle size was shown to be inversely correlated with drug and nanoparticle permeability, as confirmed with fluorescently-labeled nanoparticles. These results highlight the feasibility of designing nanoparticles capable of delivering medication to the fetus, in particular, potential dexamethasone therapy for the prenatal treatment of congenital adrenal hyperplasia. PMID:23850397

Effective Thermo-Capillary Mixing in Droplet Microfluidics Integrated with a Microwave Heater.

PubMed

Yesiloz, Gurkan; Boybay, Muhammed S; Ren, Carolyn L

2017-02-07

In this study, we present a microwave-based microfluidic mixer that allows rapid mixing within individual droplets efficiently. The designed microwave mixer is a coplanar design with a small footprint, which is fabricated on a glass substrate and integrated with a microfluidic chip. The mixer works essentially as a resonator that accumulates an intensive electromagnetic field into a spiral capacitive gap (around 200 μm), which provides sufficient energy to heat-up droplets that pass through the capacitive gap. This microwave actuation induces nonuniform Marangoni stresses on the interface, which results in three-dimensional motion inside the droplet and thus fast mixing. In order to evaluate the performance of the microwave mixer, droplets with highly viscous fluid, 75% (w/w) glycerol solution, were generated, half of which were seeded with fluorescent dye for imaging purposes. The relative importance of different driving forces for mixing was evaluated qualitatively using magnitude analysis, and the effect of the applied power on mixing performance was also investigated. Mixing efficiency was quantified using the mixing index, which shows as high as 97% mixing efficiency was achieved within the range of milliseconds. This work demonstrates a very unique approach of utilizing microwave technology to facilitate mixing in droplet microfluidics systems, which can potentially open up areas for biochemical synthesis applications.

Enhancement of dissolution and oral bioavailability of lacidipine via pluronic P123/F127 mixed polymeric micelles: formulation, optimization using central composite design and in vivo bioavailability study.

PubMed

Fares, Ahmed R; ElMeshad, Aliaa N; Kassem, Mohamed A A

2018-11-01

This study aims at preparing and optimizing lacidipine (LCDP) polymeric micelles using thin film hydration technique in order to overcome LCDP solubility-limited oral bioavailability. A two-factor three-level central composite face-centered design (CCFD) was employed to optimize the formulation variables to obtain LCDP polymeric micelles of high entrapment efficiency and small and uniform particle size (PS). Formulation variables were: Pluronic to drug ratio (A) and Pluronic P123 percentage (B). LCDP polymeric micelles were assessed for entrapment efficiency (EE%), PS and polydispersity index (PDI). The formula with the highest desirability (0.959) was chosen as the optimized formula. The values of the formulation variables (A and B) in the optimized polymeric micelles formula were 45% and 80%, respectively. Optimum LCDP polymeric micelles had entrapment efficiency of 99.23%, PS of 21.08 nm and PDI of 0.11. Optimum LCDP polymeric micelles formula was physically characterized using transmission electron microscopy. LCDP polymeric micelles showed saturation solubility approximately 450 times that of raw LCDP in addition to significantly enhanced dissolution rate. Bioavailability study of optimum LCDP polymeric micelles formula in rabbits revealed a 6.85-fold increase in LCDP bioavailability compared to LCDP oral suspension.

Sachem: a chemical cartridge for high-performance substructure search.

PubMed

Kratochvíl, Miroslav; Vondrášek, Jiří; Galgonek, Jakub

2018-05-23

Structure search is one of the valuable capabilities of small-molecule databases. Fingerprint-based screening methods are usually employed to enhance the search performance by reducing the number of calls to the verification procedure. In substructure search, fingerprints are designed to capture important structural aspects of the molecule to aid the decision about whether the molecule contains a given substructure. Currently available cartridges typically provide acceptable search performance for processing user queries, but do not scale satisfactorily with dataset size. We present Sachem, a new open-source chemical cartridge that implements two substructure search methods: The first is a performance-oriented reimplementation of substructure indexing based on the OrChem fingerprint, and the second is a novel method that employs newly designed fingerprints stored in inverted indices. We assessed the performance of both methods on small, medium, and large datasets containing 1, 10, and 94 million compounds, respectively. Comparison of Sachem with other freely available cartridges revealed improvements in overall performance, scaling potential and screen-out efficiency. The Sachem cartridge allows efficient substructure searches in databases of all sizes. The sublinear performance scaling of the second method and the ability to efficiently query large amounts of pre-extracted information may together open the door to new applications for substructure searches.

Assessing the relationship between the inter-rod coupling and the efficiency of piezocomposite high-intensity focused ultrasound transducers.

PubMed

Chen, Gin-Shin; Pan, Chia-Ching; Lin, Yu-Li; Cheng, Jung-Sung

2014-03-01

The electroacoustic conversion efficiency of the ultrasonic transducer is a critical performance index for high-power applications. The material properties, volume fraction (VF) and aspect ratio (AR) are typically regarded as the design parameters of the piezocomposite transducer. We hypothesized that the spacing between piezoelectric rods was also a dominant factor. Therefore, the inter-rod coupling effects on the efficiency of 1-3 piezocomposite ultrasonic transducers were investigated in this study. The efficiencies of six flat and three curved 1.0 MHz PZT4 epoxy composite transducers with different geometric parameters were measured. Finite element transient analyses of the inter-rod electrical-mechanical coupling in the composites were carried out to explain the measured results. The experimental results showed that for 0.47 AR, the 79% VF transducers had lower efficiency than the 64% VF and 53% VF transducers. For 0.19 AR, the efficiency of the 59% VF transducer was not greater than the efficiency of the 39% VF transducer. Numerical analyses demonstrated that the positive peak voltage induced by the coupling of the side rods was more than twice the level induced by the coupling of the diagonal rods for any spacing. The diagonal coupling voltage peak did not change for spacings larger than 0.2 mm. Moreover, for spacings of 0.05 and 0.1 mm, the inter-rod coupling caused 24% and 20% waveform shifts of the driving voltage, respectively, while the 0.2 mm spacing coupling caused a 14% reduction in the amplitude of the driving voltage. As a result, the asymmetry of the driving voltage degraded the efficiency of the composite transducers and became more severe when the spacing was decreased. We concluded that the efficiency loss induced by inter-rod coupling as a function of spacing should be considered when designing piezocomposite transducers. Copyright © 2013 Elsevier B.V. All rights reserved.

Photopolymers for holographic optical elements in astronomy

NASA Astrophysics Data System (ADS)

Zanutta, A.; Orselli, E.; Fäcke, T.; Bianco, A.

2017-05-01

Holographic Optical Elements (HOEs) cover nowadays a relevant position as dispersing elements in astronomical spectrographs because each astronomical observation could take advantage of specific devices with features tailored for achieving the best performances. The design and manufacturing of highly efficient and reliable dispersive elements require photosensitive materials as recording substrate where it is possible to precisely control the parameters that define the efficiency response (namely both the refractive index modulation and the film thickness). The most promising materials in this field are the photopolymers because, beside the ability to provide the tuning feature, they bring also advantages such as self-developing, high refractive index modulation and ease of use thanks to their simple thin structure, which is insensitive from the external environment. In particular, Bayfol HX photopolymers were characterized with the purpose to use them as new material for astronomical Volume Phase Holographic Gratings. We designed and manufactured VPHGs for astronomical instrumentation and we demonstrated how photopolymers are reliable holographic materials for making astronomical devices with performances comparable to those provided by VPHGs based on Dichromated Gelatins (DCGs), but with a much simpler production process. Moreover, the versatility of these materials allowed us to propose and realize novel architectures of the spectroscopic dispersive elements. A compact and unique single prism device was realized for a FOSC spectrograph and new multi-layered devices are proposed, stacking VPHGs one on top of the other to obtain many spectra in the instrument's detector, with advantages as increase of resolution and signal to noise ratio with respect to the classical single dispersive element.

Multi-Level Bitmap Indexes for Flash Memory Storage

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

Wu, Kesheng; Madduri, Kamesh; Canon, Shane

2010-07-23

Due to their low access latency, high read speed, and power-efficient operation, flash memory storage devices are rapidly emerging as an attractive alternative to traditional magnetic storage devices. However, tests show that the most efficient indexing methods are not able to take advantage of the flash memory storage devices. In this paper, we present a set of multi-level bitmap indexes that can effectively take advantage of flash storage devices. These indexing methods use coarsely binned indexes to answer queries approximately, and then use finely binned indexes to refine the answers. Our new methods read significantly lower volumes of data atmore » the expense of an increased disk access count, thus taking full advantage of the improved read speed and low access latency of flash devices. To demonstrate the advantage of these new indexes, we measure their performance on a number of storage systems using a standard data warehousing benchmark called the Set Query Benchmark. We observe that multi-level strategies on flash drives are up to 3 times faster than traditional indexing strategies on magnetic disk drives.« less

Breaking the Curse of Cardinality on Bitmap Indexes

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

Wu, Kesheng; Wu, Kesheng; Stockinger, Kurt

2008-04-04

Bitmap indexes are known to be efficient for ad-hoc range queries that are common in data warehousing and scientific applications. However, they suffer from the curse of cardinality, that is, their efficiency deteriorates as attribute cardinalities increase. A number of strategies have been proposed, but none of them addresses the problem adequately. In this paper, we propose a novel binned bitmap index that greatly reduces the cost to answer queries, and therefore breaks the curse of cardinality. The key idea is to augment the binned index with an Order-preserving Bin-based Clustering (OrBiC) structure. This data structure significantly reduces the I/Omore » operations needed to resolve records that cannot be resolved with the bitmaps. To further improve the proposed index structure, we also present a strategy to create single-valued bins for frequent values. This strategy reduces index sizes and improves query processing speed. Overall, the binned indexes with OrBiC great improves the query processing speed, and are 3 - 25 times faster than the best available indexes for high-cardinality data.« less

Design and optimization of cascaded DCG based holographic elements for spectrum-splitting PV systems

NASA Astrophysics Data System (ADS)

Wu, Yuechen; Chrysler, Benjamin; Pelaez, Silvana Ayala; Kostuk, Raymond K.

2017-09-01

In this work, the technique of designing and optimizing broadband volume transmission holograms using dichromate gelatin (DCG) is summarized for solar spectrum-splitting application. Spectrum splitting photovoltaic system uses a series of single bandgap PV cells that have different spectral conversion efficiency properties to more fully utilize the solar spectrum. In such a system, one or more high performance optical filters are usually required to split the solar spectrum and efficiently send them to the corresponding PV cells. An ideal spectral filter should have a rectangular shape with sharp transition wavelengths. DCG is a near ideal holographic material for solar applications as it can achieve high refractive index modulation, low absorption and scattering properties and long-term stability to solar exposure after sealing. In this research, a methodology of designing and modeling a transmission DCG hologram using coupled wave analysis for different PV bandgap combinations is described. To achieve a broad diffraction bandwidth and sharp cut-off wavelength, a cascaded structure of multiple thick holograms is described. A search algorithm is also developed to optimize both single and two-layer cascaded holographic spectrum splitters for the best bandgap combinations of two- and three-junction SSPV systems illuminated under the AM1.5 solar spectrum. The power conversion efficiencies of the optimized systems under the AM1.5 solar spectrum are then calculated using the detailed balance method, and shows an improvement compared with tandem structure.

Solid-state laser pumping with a planar compound parabolic concentrator.

PubMed

Panteli, D V; Pani, B M; Beli, L Z

1997-10-20

A novel solid-state laser-pumping scheme is proposed that combines a reflective lamp chamber and a compound parabolic concentrator (CPC) as a light guide. The CPC is made of a transparent material of high refractive index, and light is guided by the total internal reflection, with drastically reduced reflection losses. Material is chosen so that the absorption losses are minimized in the pumping wavelength range. The lamp chamber is designed with the principles of nonimaging optics, which ensures that the radiation is efficiently transferred from the lamp to the input aperture of the CPC. The pumping efficiency was first estimated theoretically, which gave us enough justification for the more accurate calculations with ray tracing. Single as well as multiple pumping cavities are discussed. New pumping geometry results in significantly increased pumping efficiency compared with conventional geometries. Also the lamp and the laser rod are separated, leading to reduced thermal load. We found that the proposed pumping method is also applicable to diode-pumped lasers.

Mid-infrared supercontinuum generation in As2S3-silica "nano-spike" step-index waveguide.

PubMed

Granzow, N; Schmidt, M A; Chang, W; Wang, L; Coulombier, Q; Troles, J; Toupin, P; Hartl, I; Lee, K F; Fermann, M E; Wondraczek, L; Russell, P St J

2013-05-06

Efficient generation of a broad-band mid-infrared supercontinuum spectrum is reported in an arsenic trisulphide waveguide embedded in silica. A chalcogenide "nano-spike", designed to transform the incident light adiabatically into the fundamental mode of a 2-mm-long uniform section 1 µm in diameter, is used to achieve high launch efficiencies. The nano-spike is fully encapsulated in a fused silica cladding, protecting it from the environment. Nano-spikes provide a convenient means of launching light into sub-wavelength scale waveguides. Ultrashort (65 fs, repetition rate 100 MHz) pulses at wavelength 2 µm, delivered from a Tm-doped fiber laser, are launched with an efficiency ~12% into the sub-wavelength chalcogenide waveguide. Soliton fission and dispersive wave generation along the uniform section result in spectral broadening out to almost 4 µm for launched energies of only 18 pJ. The spectrum generated will have immediate uses in metrology and infrared spectroscopy.

High Efficiency Quantum Well Waveguide Solar Cells and Methods for Constructing the Same

NASA Technical Reports Server (NTRS)

Sood, Ashok K. (Inventor); Welser, Roger E. (Inventor)

2014-01-01

Photon absorption, and thus current generation, is hindered in conventional thin-film solar cell designs, including quantum well structures, by the limited path length of incident light passing vertically through the device. Optical scattering into lateral waveguide structures provides a physical mechanism to increase photocurrent generation through in-plane light trapping. However, the insertion of wells of high refractive index material with lower energy gap into the device structure often results in lower voltage operation, and hence lower photovoltaic power conversion efficiency. The voltage output of an InGaAs quantum well waveguide photovoltaic device can be increased by employing a III-V material structure with an extended wide band gap emitter heterojunction. Analysis of the light IV characteristics reveals that non-radiative recombination components of the underlying dark diode current have been reduced, exposing the limiting radiative recombination component and providing a pathway for realizing solar-electric conversion efficiency of 30% or more in single junction cells.

Screening of formulation variables for the preparation of poly(epsilon-caprolactone) nanocapsules containing the local anesthetic benzocaine.

PubMed

Moraes, Carolina Morales; de Matos, Angélica Prado; Grillo, Renato; de Melo, Nathalie F S; de Paula, Eneida; Dias Filho, Newton Luiz; Rosa, André Henrique; Fraceto, Leonardo Fernandes

2011-03-01

In this work we describe the screening of four parameters in the preparation, by nanoprecipitation, of poly(epsilon-caprolactone) nanocapsules, used as a drug carrier system for the local anesthetic, benzocaine. A 2(4-1) factorial experimental design was used to study the influence of four different independent variables (polymer, oily phase, Span 60 and Tween 80) on nanocapsule characteristics (size, polydispersion index, zeta potential) and drug loading capability. Best results were obtained using an aqueous formulation comprising 100 mg of polymer, 200 mg of oily phase, 40 mg of Span 60 and 60 mg of Tween 80 in a final volume of 10 mL which produced a colloidal system with particle size of 188 nm, zeta potential -32 mV, polydispersion index 0.07, and benzocaine association efficiency > 87%. These findings open the way for future clinical studies using such formulations.

Influence of micromixer characteristics on polydispersity index of block copolymers synthesized in continuous flow microreactors.

PubMed

Rosenfeld, Carine; Serra, Christophe; Brochon, Cyril; Hadziioannou, Georges

2008-10-01

The influence of interdigital multilamination micromixer characteristics on monomer conversions, molecular weights and especially on the polydispersity index of block copolymers synthesized continuously in two microtube reactors is investigated. The micromixers are used to mix, before copolymerization, a polymer solution with different viscosities and the second monomer. Different geometries of micromixer (number of microchannels, characteristic lengths) have been studied. It was found that polydispersity indices of the copolymers follow a linear relationship with the Reynolds number in the micromixer, represented by a form factor. Thus, beside the operating conditions (nature of the first block and comonomer flow rate), the choice of the micromixer geometry and dimension is essential to control the copolymerization in terms of molecular weights and polydispersity indices. This linear correlation allows the prediction of copolymer features. It can also be a new method to optimize existing micromixers or design other geometries so that mixing could be more efficient.

KSC Construction Cost Index

NASA Technical Reports Server (NTRS)

Brown, J. A.

1983-01-01

Kennedy Space Center cost Index aids in conceptual design cost estimates. Report discusses development of KSC Cost Index since January 1974. Index since January 1974. Index provides management, design engineers, and estimators an up-to-data reference for local labor and material process. Also provides mount and rate of change in these costs used to predict future construction costs.

Refraction-Assisted Solar Thermoelectric Generator based on Phase-Change Lens

PubMed Central

Kim, Myoung-Soo; Kim, Min-Ki; Jo, Sung-Eun; Joo, Chulmin; Kim, Yong-Jun

2016-01-01

Solar thermoelectric generators (STEGs), which are used for various applications, (particularly small size electronic devices), have optical concentration systems for high energy conversion efficiency. In this study, a refraction-assisted STEG (R-STEG) is designed based on phase-change materials. As the phase-change material (PCM) changes phase from solid to liquid, its refractive index and transmittance also change, resulting in changes in the refraction of the sunlight transmitted through it, and concentration of solar energy in the phase-change lens. This innovative design facilitates double focusing the solar energy through the optical lens and a phase-change lens. This mechanism resulted in the peak energy conversion efficiencies of the R-STEG being 60% and 86% higher than those of the typical STEG at solar intensities of 1 kW m−2 and 1.5 kW m−2, respectively. In addition, the energy stored in PCM can help to generate steady electrical energy when the solar energy was removed. This work presents significant progress regarding the optical characteristic of PCM and optical concentration systems of STEGs. PMID:27283350

Composite Yb:YAG/SiC-prism thin disk laser.

PubMed

Newburgh, G A; Michael, A; Dubinskii, M

2010-08-02

We report the first demonstration of a Yb:YAG thin disk laser wherein the gain medium is intracavity face-cooled through bonding to an optical quality SiC prism. Due to the particular design of the composite bonded Yb:YAG/SiC-prism gain element, the laser beam impinges on all refractive index interfaces inside the laser cavity at Brewster's angles. The laser beam undergoes total internal reflection (TIR) at the bottom of the Yb(10%):YAG thin disk layer in a V-bounce cavity configuration. Through the use of TIR and Brewster's angles, no optical coatings, either anti-reflective (AR) or highly reflective (HR), are required inside the laser cavity. In this first demonstration, the 936.5-nm diode pumped laser performed with approximately 38% slope efficiency at 12 W of quasi-CW (Q-CW) output power at 1030 nm with a beam quality measured at M(2) = 1.5. This demonstration opens up a viable path toward novel thin disk laser designs with efficient double-sided room-temperature heatsinking via materials with the thermal conductivity of copper on both sides of the disk.

Refraction-Assisted Solar Thermoelectric Generator based on Phase-Change Lens.

PubMed

Kim, Myoung-Soo; Kim, Min-Ki; Jo, Sung-Eun; Joo, Chulmin; Kim, Yong-Jun

2016-06-10

Solar thermoelectric generators (STEGs), which are used for various applications, (particularly small size electronic devices), have optical concentration systems for high energy conversion efficiency. In this study, a refraction-assisted STEG (R-STEG) is designed based on phase-change materials. As the phase-change material (PCM) changes phase from solid to liquid, its refractive index and transmittance also change, resulting in changes in the refraction of the sunlight transmitted through it, and concentration of solar energy in the phase-change lens. This innovative design facilitates double focusing the solar energy through the optical lens and a phase-change lens. This mechanism resulted in the peak energy conversion efficiencies of the R-STEG being 60% and 86% higher than those of the typical STEG at solar intensities of 1 kW m(-2) and 1.5 kW m(-2), respectively. In addition, the energy stored in PCM can help to generate steady electrical energy when the solar energy was removed. This work presents significant progress regarding the optical characteristic of PCM and optical concentration systems of STEGs.

Highly efficient birefringent quarter-wave plate based on all-dielectric metasurface and graphene

NASA Astrophysics Data System (ADS)

Owiti, Edgar O.; Yang, Hanning; Liu, Peng; Ominde, Calvine F.; Sun, Xiudong

2018-07-01

All-dielectric metasurfaces offer remarkable properties including high efficiency and flexible control of the optical response. However, extreme, narrow bandwidth is a limitation that lowers applicability of these structures in photonic sensing applications. In this work, we numerically design and propose a switchable quarter-wave plate by hybridizing an all-dielectric metasurface with graphene. By using a single layer of graphene between a highly refractive index silicon and a silica substrate, the transmissive resonance is enhanced and broadened. Additionally, integrating graphene with silicon effectively modulates the Q-factor and the trapped magnetic modes in the silicon. A stable birefringence output is obtained and manipulated through the structure dimensions and the Fermi energy of graphene. A 95% polarization conversion ratio is achieved through converting linearly polarized light into circularly polarized light, and a 96% ellipticity ratio is obtained at the resonance wavelength. The structure is compact and has an ultrathin design thickness of 0 . 1 λ, in the telecommunication region. The above properties are essential for integration into photonic sensing devices and the structure has potential for compatibility with the CMOS devices.

Whole genome analysis of CRISPR Cas9 sgRNA off-target homologies via an efficient computational algorithm.

PubMed

Zhou, Hong; Zhou, Michael; Li, Daisy; Manthey, Joseph; Lioutikova, Ekaterina; Wang, Hong; Zeng, Xiao

2017-11-17

The beauty and power of the genome editing mechanism, CRISPR Cas9 endonuclease system, lies in the fact that it is RNA-programmable such that Cas9 can be guided to any genomic loci complementary to a 20-nt RNA, single guide RNA (sgRNA), to cleave double stranded DNA, allowing the introduction of wanted mutations. Unfortunately, it has been reported repeatedly that the sgRNA can also guide Cas9 to off-target sites where the DNA sequence is homologous to sgRNA. Using human genome and Streptococcus pyogenes Cas9 (SpCas9) as an example, this article mathematically analyzed the probabilities of off-target homologies of sgRNAs and discovered that for large genome size such as human genome, potential off-target homologies are inevitable for sgRNA selection. A highly efficient computationl algorithm was developed for whole genome sgRNA design and off-target homology searches. By means of a dynamically constructed sequence-indexed database and a simplified sequence alignment method, this algorithm achieves very high efficiency while guaranteeing the identification of all existing potential off-target homologies. Via this algorithm, 1,876,775 sgRNAs were designed for the 19,153 human mRNA genes and only two sgRNAs were found to be free of off-target homology. By means of the novel and efficient sgRNA homology search algorithm introduced in this article, genome wide sgRNA design and off-target analysis were conducted and the results confirmed the mathematical analysis that for a sgRNA sequence, it is almost impossible to escape potential off-target homologies. Future innovations on the CRISPR Cas9 gene editing technology need to focus on how to eliminate the Cas9 off-target activity.

Transportation Energy Efficiency Program (TEEP) Report Abstracts

DOT National Transportation Integrated Search

1977-04-15

This bibliography summarizes the published research accomplished for the Department of Transportation's Transportation Energy Efficiency Program and its predecessor, the Automotive Energy Efficiency Program. The reports are indexed by corporate autho...

Optimizing nitrogen application rate and plant density for improving cotton yield and nitrogen use efficiency in the North China Plain

PubMed Central

Dong, Helin; Zheng, Cangsong; Sun, Miao; Liu, Aizhong; Wang, Guoping; Liu, Shaodong; Zhang, Siping; Chen, Jing; Li, Yabing; Pang, Chaoyou; Zhao, Xinhua

2017-01-01

Plant population density (PPD) and nitrogen (N) application rate (NAR) are two controllable factors in cotton production. We conducted field experiments to investigate the effects of PPD, NAR and their interaction (PPD × NAR) on yield, N uptake and N use efficiency (NUE) of cotton using a split-plot design in the North China Plain during 2013 and 2014. The main plots were PPDs (plants m−2) of 3.00 (low), 5.25 (medium) and 7.50 (high) and the subplots were NARs of 0 (N-free), 112.5 (low), 225.0 (moderate) and 337.5 (high). During both 2013 and 2014, biological yield and N uptake of cotton increased significantly, but harvesting index decreased significantly with NAR and PPD increasing. With NAR increasing, internal nitrogen use efficiency(NUE) decreased significantly under three PPDs and agronomical NUE, physiologilal NUE, nitrogen recovery efficiency(NRE) and partial factor productivity from applied nitrogen (PFPN) also decreased significantly under high PPD between two years. Lint yield increment varied during different PPDs and years, but NAR enhancement showed less function under higher PPD than lower PPD in general. Taken together, moderate NAR under medium PPD combined higher lint yield with higher agronomic NUE, physiological NUE, and NRE, while low NAR with high PPD would achieve a comparable yield with superior NRE and PFPN and high NAR under high PPD and medium PPD produced higher biological yield but lower harvest index, lint yield and NUE compared to moderate NAR with medium PPD. Our overall results indicated that, in this region, increasing PPD and decreasing NAR properly would enhance both lint yield and NUE of cotton. PMID:28981538

Quality indexing with computer-aided lexicography

NASA Technical Reports Server (NTRS)

Buchan, Ronald L.

1992-01-01

Indexing with computers is a far cry from indexing with the first indexing tool, the manual card sorter. With the aid of computer-aided lexicography, both indexing and indexing tools can provide standardization, consistency, and accuracy, resulting in greater quality control than ever before. A brief survey of computer activity in indexing is presented with detailed illustrations from NASA activity. Applications from techniques mentioned, such as Retrospective Indexing (RI), can be made to many indexing systems. In addition to improving the quality of indexing with computers, the improved efficiency with which certain tasks can be done is demonstrated.

A novel biomedical image indexing and retrieval system via deep preference learning.

PubMed

Pang, Shuchao; Orgun, Mehmet A; Yu, Zhezhou

2018-05-01

The traditional biomedical image retrieval methods as well as content-based image retrieval (CBIR) methods originally designed for non-biomedical images either only consider using pixel and low-level features to describe an image or use deep features to describe images but still leave a lot of room for improving both accuracy and efficiency. In this work, we propose a new approach, which exploits deep learning technology to extract the high-level and compact features from biomedical images. The deep feature extraction process leverages multiple hidden layers to capture substantial feature structures of high-resolution images and represent them at different levels of abstraction, leading to an improved performance for indexing and retrieval of biomedical images. We exploit the current popular and multi-layered deep neural networks, namely, stacked denoising autoencoders (SDAE) and convolutional neural networks (CNN) to represent the discriminative features of biomedical images by transferring the feature representations and parameters of pre-trained deep neural networks from another domain. Moreover, in order to index all the images for finding the similarly referenced images, we also introduce preference learning technology to train and learn a kind of a preference model for the query image, which can output the similarity ranking list of images from a biomedical image database. To the best of our knowledge, this paper introduces preference learning technology for the first time into biomedical image retrieval. We evaluate the performance of two powerful algorithms based on our proposed system and compare them with those of popular biomedical image indexing approaches and existing regular image retrieval methods with detailed experiments over several well-known public biomedical image databases. Based on different criteria for the evaluation of retrieval performance, experimental results demonstrate that our proposed algorithms outperform the state-of-the-art techniques in indexing biomedical images. We propose a novel and automated indexing system based on deep preference learning to characterize biomedical images for developing computer aided diagnosis (CAD) systems in healthcare. Our proposed system shows an outstanding indexing ability and high efficiency for biomedical image retrieval applications and it can be used to collect and annotate the high-resolution images in a biomedical database for further biomedical image research and applications. Copyright © 2018 Elsevier B.V. All rights reserved.

A maintenance time prediction method considering ergonomics through virtual reality simulation.

PubMed

Zhou, Dong; Zhou, Xin-Xin; Guo, Zi-Yue; Lv, Chuan

2016-01-01

Maintenance time is a critical quantitative index in maintainability prediction. An efficient maintenance time measurement methodology plays an important role in early stage of the maintainability design. While traditional way to measure the maintenance time ignores the differences between line production and maintenance action. This paper proposes a corrective MOD method considering several important ergonomics factors to predict the maintenance time. With the help of the DELMIA analysis tools, the influence coefficient of several factors are discussed to correct the MOD value and the designers can measure maintenance time by calculating the sum of the corrective MOD time of each maintenance therbligs. Finally a case study is introduced, by maintaining the virtual prototype of APU motor starter in DELMIA, designer obtains the actual maintenance time by the proposed method, and the result verifies the effectiveness and accuracy of the proposed method.

Improved approximations for control augmented structural synthesis

NASA Technical Reports Server (NTRS)

Thomas, H. L.; Schmit, L. A.

1990-01-01

A methodology for control-augmented structural synthesis is presented for structure-control systems which can be modeled as an assemblage of beam, truss, and nonstructural mass elements augmented by a noncollocated direct output feedback control system. Truss areas, beam cross sectional dimensions, nonstructural masses and rotary inertias, and controller position and velocity gains are treated simultaneously as design variables. The structural mass and a control-system performance index can be minimized simultaneously, with design constraints placed on static stresses and displacements, dynamic harmonic displacements and forces, structural frequencies, and closed-loop eigenvalues and damping ratios. Intermediate design-variable and response-quantity concepts are used to generate new approximations for displacements and actuator forces under harmonic dynamic loads and for system complex eigenvalues. This improves the overall efficiency of the procedure by reducing the number of complete analyses required for convergence. Numerical results which illustrate the effectiveness of the method are given.

Dielectric Meta-Holograms Enabled with Dual Magnetic Resonances in Visible Light.

PubMed

Li, Zile; Kim, Inki; Zhang, Lei; Mehmood, Muhammad Q; Anwar, Muhammad S; Saleem, Murtaza; Lee, Dasol; Nam, Ki Tae; Zhang, Shuang; Luk'yanchuk, Boris; Wang, Yu; Zheng, Guoxing; Rho, Junsuk; Qiu, Cheng-Wei

2017-09-26

Efficient transmission-type meta-holograms have been demonstrated using high-index dielectric nanostructures based on Huygens' principle. It is crucial that the geometry size of building blocks be judiciously optimized individually for spectral overlap of electric and magnetic dipoles. In contrast, reflection-type meta-holograms using the metal/insulator/metal scheme and geometric phase can be readily achieved with high efficiency and small thickness. Here, we demonstrate a general platform for design of dual magnetic resonance based meta-holograms based on the geometric phase using silicon nanostructures that are quarter wavelength thick for visible light. Significantly, the projected holographic image can be unambiguously observed without a receiving screen even under the illumination of natural light. Within the well-developed semiconductor industry, our ultrathin magnetic resonance-based meta-holograms may have promising applications in anticounterfeiting and information security.

Multifractality, efficiency analysis of Chinese stock market and its cross-correlation with WTI crude oil price

NASA Astrophysics Data System (ADS)

Zhuang, Xiaoyang; Wei, Yu; Ma, Feng

2015-07-01

In this paper, the multifractality and efficiency degrees of ten important Chinese sectoral indices are evaluated using the methods of MF-DFA and generalized Hurst exponents. The study also scrutinizes the dynamics of the efficiency of Chinese sectoral stock market by the rolling window approach. The overall empirical findings revealed that all the sectoral indices of Chinese stock market exist different degrees of multifractality. The results of different efficiency measures have agreed on that the 300 Materials index is the least efficient index. However, they have a slight diffidence on the most efficient one. The 300 Information Technology, 300 Telecommunication Services and 300 Health Care indices are comparatively efficient. We also investigate the cross-correlations between the ten sectoral indices and WTI crude oil price based on Multifractal Detrended Cross-correlation Analysis. At last, some relevant discussions and implications of the empirical results are presented.

Optimization of OSPF Routing in IP Networks

NASA Astrophysics Data System (ADS)

Bley, Andreas; Fortz, Bernard; Gourdin, Eric; Holmberg, Kaj; Klopfenstein, Olivier; Pióro, Michał; Tomaszewski, Artur; Ümit, Hakan

The Internet is a huge world-wide packet switching network comprised of more than 13,000 distinct subnetworks, referred to as Autonomous Systems (ASs) autonomous system AS . They all rely on the Internet Protocol (IP) internet protocol IP for transport of packets across the network. And most of them use shortest path routing protocols shortest path routing!protocols , such as OSPF or IS-IS, to control the routing of IP packets routing!of IP packets within an AS. The idea of the routing is extremely simple — every packet is forwarded on IP links along the shortest route between its source and destination nodes of the AS. The AS network administrator can manage the routing of packets in the AS by supplying the so-called administrative weights of IP links, which specify the link lengths that are used by the routing protocols for their shortest path computations. The main advantage of the shortest path routing policy is its simplicity, allowing for little administrative overhead. From the network engineering perspective, however, shortest path routing can pose problems in achieving satisfactory traffic handling efficiency. As all routing paths depend on the same routing metric routing!metric , it is not possible to configure the routing paths for the communication demands between different pairs of nodes explicitly or individually; the routing can be controlled only indirectly and only as a whole by modifying the routing metric. Thus, one of the main tasks when planning such networks is to find administrative link weights that induce a globally efficient traffic routing traffic!routing configuration of an AS. It turns out that this task leads to very difficult mathematical optimization problems. In this chapter, we discuss and describe exact integer programming models and solution approaches as well as practically efficient smart heuristics for such shortest path routing problems shortest path routing!problems .

Using Bitmap Indexing Technology for Combined Numerical and TextQueries

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

Stockinger, Kurt; Cieslewicz, John; Wu, Kesheng

2006-10-16

In this paper, we describe a strategy of using compressedbitmap indices to speed up queries on both numerical data and textdocuments. By using an efficient compression algorithm, these compressedbitmap indices are compact even for indices with millions of distinctterms. Moreover, bitmap indices can be used very efficiently to answerBoolean queries over text documents involving multiple query terms.Existing inverted indices for text searches are usually inefficient forcorpora with a very large number of terms as well as for queriesinvolving a large number of hits. We demonstrate that our compressedbitmap index technology overcomes both of those short-comings. In aperformance comparison against amore » commonly used database system, ourindices answer queries 30 times faster on average. To provide full SQLsupport, we integrated our indexing software, called FastBit, withMonetDB. The integrated system MonetDB/FastBit provides not onlyefficient searches on a single table as FastBit does, but also answersjoin queries efficiently. Furthermore, MonetDB/FastBit also provides avery efficient retrieval mechanism of result records.« less

"Peak tracking chip" for label-free optical detection of bio-molecular interaction and bulk sensing.

PubMed

Bougot-Robin, Kristelle; Li, Shunbo; Zhang, Yinghua; Hsing, I-Ming; Benisty, Henri; Wen, Weijia

2012-10-21

A novel imaging method for bulk refractive index sensing or label-free bio-molecular interaction sensing is presented. This method is based on specially designed "Peak tracking chip" (PTC) involving "tracks" of adjacent resonant waveguide gratings (RWG) "micropads" with slowly evolving resonance position. Using a simple camera the spatial information robustly retrieves the diffraction efficiency, which in turn transduces either the refractive index of the liquids on the tracks or the effective thickness of an immobilized biological layer. Our intrinsically multiplex chip combines tunability and versatility advantages of dielectric guided wave biochips without the need of costly hyperspectral instrumentation. The current success of surface plasmon imaging techniques suggests that our chip proposal could leverage an untapped potential to routinely extend such techniques in a convenient and sturdy optical configuration toward, for instance for large analytes detection. PTC design and fabrication are discussed with challenging process to control micropads properties by varying their period (step of 2 nm) or their duty cycle through the groove width (steps of 4 nm). Through monochromatic imaging of our PTC, we present experimental demonstration of bulk index sensing on the range [1.33-1.47] and of surface biomolecule detection of molecular weight 30 kDa in aqueous solution using different surface densities. A sensitivity of the order of 10(-5) RIU for bulk detection and a sensitivity of the order of ∼10 pg mm(-2) for label-free surface detection are expected, therefore opening a large range of application of our chip based imaging technique. Exploiting and chip design, we expect as well our chip to open new direction for multispectral studies through imaging.

A Compact Trench-Assisted Multi-Orbital-Angular-Momentum Multi-Ring Fiber for Ultrahigh-Density Space-Division Multiplexing (19 Rings × 22 Modes)

PubMed Central

Li, Shuhui; Wang, Jian

2014-01-01

We present a compact (130 μm cladding diameter) trench-assisted multi-orbital-angular-momentum (OAM) multi-ring fiber with 19 rings each supporting 22 modes with 18 OAM ones. Using the high-contrast-index ring and trench designs, the trench-assisted multi-OAM multi-ring fiber (TA-MOMRF) features both low-level inter-mode crosstalk and inter-ring crosstalk within a wide wavelength range (1520 to 1630 nm), which can potentially enable Pbit/s total transmission capacity and hundreds bit/s/Hz spectral efficiency in a single TA-MOMRF. Moreover, the effective refractive index difference of even and odd fiber eigenmodes induced by the ellipticity of ring and fiber bending and their impacts on the purity of OAM mode and mode coupling/crosstalk are analyzed. It is found that high-order OAM modes show preferable tolerance to the ring ellipticity and fiber bending. The designed fiber offers favorable tolerance to both small ellipticity of ring (<−22 dB crosstalk under an ellipticity of 0.5%) and small bend radius (<−20 dB crosstalk under a bend radius of 2 cm). PMID:24458159

The Helmet Fit Index--An intelligent tool for fit assessment and design customisation.

PubMed

Ellena, Thierry; Subic, Aleksandar; Mustafa, Helmy; Pang, Toh Yen

2016-07-01

Helmet safety benefits are reduced if the headgear is poorly fitted on the wearer's head. At present, there are no industry standards available to assess objectively how a specific protective helmet fits a particular person. A proper fit is typically defined as a small and uniform distance between the helmet liner and the wearer's head shape, with a broad coverage of the head area. This paper presents a novel method to investigate and compare fitting accuracy of helmets based on 3D anthropometry, reverse engineering techniques and computational analysis. The Helmet Fit Index (HFI) that provides a fit score on a scale from 0 (excessively poor fit) to 100 (perfect fit) was compared with subjective fit assessments of surveyed cyclists. Results in this study showed that quantitative (HFI) and qualitative (participants' feelings) data were related when comparing three commercially available bicycle helmets. Findings also demonstrated that females and Asian people have lower fit scores than males and Caucasians, respectively. The HFI could provide detailed understanding of helmet efficiency regarding fit and could be used during helmet design and development phases. Copyright © 2016 Elsevier Ltd and The Ergonomics Society. All rights reserved.

LED Context Lighting System in Residential Areas

PubMed Central

Im, Kyoung-Mi

2014-01-01

As issues of environment and energy draw keen interest around the globe due to such problems as global warming and the energy crisis, LED with high optical efficiency is brought to the fore as the next generation lighting. In addition, as the national income level gets higher and life expectancy is extended, interest in the enhancement of life quality is increasing. Accordingly, the trend of lightings is changing from mere adjustment of light intensity to system lighting in order to enhance the quality of one's life as well as reduce energy consumption. Thus, this study aims to design LED context lighting system that automatically recognizes the location and acts of a user in residential areas and creates an appropriate lighting environment. The proposed system designed in this study includes three types of processing: first, the creation of a lighting environment index suitable for the user's surroundings and lighting control scenarios and second, it measures and analyzes the optical characteristics that change depending on the dimming control of lighting and applies them to the index. Lastly, it adopts PIR, piezoelectric, and power sensor to grasp the location and acts of the user and create a lighting environment suitable for the current context. PMID:25101325

Mode-converting coupler for silicon-on-sapphire devices

NASA Astrophysics Data System (ADS)

Zlatanovic, S.; Offord, B. W.; Owen, M.; Shimabukuro, R.; Jacobs, E. W.

2015-02-01

Silicon-on-sapphire devices are attractive for the mid-infrared optical applications up to 5 microns due to the low loss of both silicon and sapphire in this wavelength band. Designing efficient couplers for silicon-on-sapphire devices presents a challenge due to a highly confined mode in silicon and large values of refractive index of both silicon and sapphire. Here, we present design, fabrication, and measurements of a mode-converting coupler for silicon-on-sapphire waveguides. We utilize a mode converter layout that consists of a large waveguide that is overlays a silicon inverse tapered waveguide. While this geometry was previously utilized for silicon-on-oxide devices, the novelty is in using materials that are compatible with the silicon-on-sapphire platform. In the current coupler the overlaying waveguide is made of silicon nitride. Silicon nitride is the material of choice because of the large index of refraction and low absorption from near-infrared to mid-infrared. The couplers were fabricated using a 0.25 micron silicon-on-sapphire process. The measured coupling loss from tapered lensed silica fibers to the silicon was 4.8dB/coupler. We will describe some challenges in fabrication process and discuss ways to overcome them.

Investigation of optimal conditions for production of highly crystalline nanocellulose with increased yield via novel Cr(III)-catalyzed hydrolysis: Response surface methodology.

PubMed

Chen, You Wei; Lee, Hwei Voon; Abd Hamid, Sharifah Bee

2017-12-15

For the first time, a highly efficient Cr(NO 3 ) 3 catalysis system was proposed for optimization the yield and crystallinity of nanocellulose end product. A five-level three-factor central composite design coupled with response surface methodology was employed to elucidate parameters interactions between three design factors, namely reaction temperature (x 1 ), reaction time (x 2 ) and concentration of Cr(NO 3 ) 3 (x 3 ) over a broad range of process conditions and determine the effect on crystallinity index and product yield. The developed models predicted the maximum nanocellulose yield of 87% at optimum process conditions of 70.6°C, 1.48h, and 0.48M Cr(NO 3 ) 3 . At these conditions, the obtained nanocellulose presented high crystallinity index (75.3%), spider-web-like interconnected network morphology with the average width of 31.2±14.3nm. In addition, the yielded nanocellulose rendered a higher thermal stability than that of original cellulosic source and expected to be widely used as reinforcement agent in bio-nanocomposites materials. Copyright © 2017 Elsevier Ltd. All rights reserved.

Development and optimization of enteric coated mucoadhesive microspheres of duloxetine hydrochloride using 3(2) full factorial design.

PubMed

Setia, Anupama; Kansal, Sahil; Goyal, Naveen

2013-07-01

Microspheres constitute an important part of oral drug delivery system by virtue of their small size and efficient carrier capacity. However, the success of these microspheres is limited due to their short residence time at the site of absorption. The objective of the present study was to formulate and systematically evaluate in vitro performance of enteric coated mucoadhesive microspheres of duloxetine hydrochloride (DLX), an acid labile drug. DLX microspheres were prepared by simple emulsification phase separation technique using chitosan as carrier and glutaraldehyde as a cross-linking agent. Microspheres prepared were coated with eudragit L-100 using an oil-in-oil solvent evaporation method. Eudragit L-100was used as enteric coating polymer with the aim to release the drug in small intestine The microspheres prepared were characterized by particle size, entrapment efficiency, swelling index (SI), mucoadhesion time, in vitro drug release and surface morphology. A 3(2) full factorial design was employed to study the effect of independent variables polymer-to-drug ratio (X1) and stirring speed (X2) on dependent variables, particle size, entrapment efficiency, SI, in vitro mucoadhesion and drug release up to 24 h (t24). Microspheres formed were discrete, spherical and free flowing. The microspheres exhibited good mucoadhesive property and also showed high percentage entrapment efficiency. The microspheres were able to sustain the drug release up to 24 h. Thus, the prepared enteric coated mucoadhesive microspheres may prove to be a potential controlled release formulation of DLX for oral administration.

Variance-Based Sensitivity Analysis to Support Simulation-Based Design Under Uncertainty

DOE PAGES

Opgenoord, Max M. J.; Allaire, Douglas L.; Willcox, Karen E.

2016-09-12

Sensitivity analysis plays a critical role in quantifying uncertainty in the design of engineering systems. A variance-based global sensitivity analysis is often used to rank the importance of input factors, based on their contribution to the variance of the output quantity of interest. However, this analysis assumes that all input variability can be reduced to zero, which is typically not the case in a design setting. Distributional sensitivity analysis (DSA) instead treats the uncertainty reduction in the inputs as a random variable, and defines a variance-based sensitivity index function that characterizes the relative contribution to the output variance as amore » function of the amount of uncertainty reduction. This paper develops a computationally efficient implementation for the DSA formulation and extends it to include distributions commonly used in engineering design under uncertainty. Application of the DSA method to the conceptual design of a commercial jetliner demonstrates how the sensitivity analysis provides valuable information to designers and decision-makers on where and how to target uncertainty reduction efforts.« less

Variance-Based Sensitivity Analysis to Support Simulation-Based Design Under Uncertainty

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

Opgenoord, Max M. J.; Allaire, Douglas L.; Willcox, Karen E.

Sensitivity analysis plays a critical role in quantifying uncertainty in the design of engineering systems. A variance-based global sensitivity analysis is often used to rank the importance of input factors, based on their contribution to the variance of the output quantity of interest. However, this analysis assumes that all input variability can be reduced to zero, which is typically not the case in a design setting. Distributional sensitivity analysis (DSA) instead treats the uncertainty reduction in the inputs as a random variable, and defines a variance-based sensitivity index function that characterizes the relative contribution to the output variance as amore » function of the amount of uncertainty reduction. This paper develops a computationally efficient implementation for the DSA formulation and extends it to include distributions commonly used in engineering design under uncertainty. Application of the DSA method to the conceptual design of a commercial jetliner demonstrates how the sensitivity analysis provides valuable information to designers and decision-makers on where and how to target uncertainty reduction efforts.« less

[Assessment and comparison of hospital operating efficiency under different management systems].

PubMed

2017-06-18

To assess and analyze the operation efficiency of 8 commission general public hospitals managed directly by National Health and Family Planning Commission and 8 municipal general hospitals managed directly by Beijing Municipal Administration of Hospitals in Beijing and to provide suggestions on improving service capacity and designing relevant health policy. Input and output data of 8 commission hospitals and 8 municipal hospitals were obtained from Beijing Direct-Reported Health Statistics data from 2011 to 2014. Data envelopment analysis was used as the hospital operation efficiency measurement tool. The CCR and BCC models were built to calculate technical efficiency (TE), pure technical efficiency (PTE), scale efficiency (SE) and the status of scale efficiency of 16 hospitals in 2011 and 2014; the Malmquist index model was built to analyze the total factor productivity change (TFPC), technological change (TC), technical efficiency change, pure technical efficiency change and scale efficiency change of the 16 hospitals from 2011 to 2014. In 2011, the TE, PTE and SE of the commission hospitals were higher than those of the municipal hospitals, and the TEs of the commission hospitals and the municipal hospitals were 0.918 and 0.873 respectively. In 2014, the TE, PTE and SE of commission hospitals were lower than those of the municipal hospitals, and the TE of the commission hospitals and the municipal hospitals were 0.906 and 0.951, respectively, which was contrary to the results in 2011. According to the Malmquist index model, the average of TFPC of the municipal hospitals was larger than that of the commission hospitals, the former increased 5.9% and the latter increased 2.8% per year; the average of TC was greater than the one in both the municipal hospitals and the commission hospitals, with a growth of 3.2% and 2.9% per year, respectively; the average growth of PTE in the commission hospitals was lower than that of the municipal hospitals, and the average descent of SE in the commission hospitals was larger than that in the municipal hospitals. There are significant differences in the operation efficiency between different management systems and the main factors associated with operation efficiency are the technological and management level. Given scale efficiency status and macroeconomic medical policies, the commission hospitals and the municipal hospitals require further adjusting the distribution of medical resources, and it is of great significance for all the commission hospitals and the municipal hospitals to improve the management level and resource integration capability.

Design and analysis of photonic optical switches with improved wavelength selectivity

NASA Astrophysics Data System (ADS)

Wielichowski, Marcin; Patela, Sergiusz

2005-09-01

Efficient optical modulators and switches are the key elements of the future all-optical fiber networks. Aside from numerous advantages, the integrated optical devices suffer from excessive longitudinal dimensions. The dimensions may be significantly reduced with help of periodic structures, such as Bragg gratings, arrayed waveguides or multilayer structures. In this paper we describe methods of analysis and example of analytical results of a photonic switch with properties modified by the application of periodic change of effective refractive index. The switch is composed of a strip-waveguide directional coupler and a transversal Bragg grating.

Biomechanics of cellular solids.

PubMed

Gibson, Lorna J

2005-03-01

Materials with a cellular structure are widespread in nature and include wood, cork, plant parenchyma and trabecular bone. Natural cellular materials are often mechanically efficient: the honeycomb-like microstructure of wood, for instance, gives it an exceptionally high performance index for resisting bending and buckling. Here we review the mechanics of a wide range of natural cellular materials and examine their role in lightweight natural sandwich structures (e.g. iris leaves) and natural tubular structures (e.g. plant stems or animal quills). We also describe two examples of engineered biomaterials with a cellular structure, designed to replace or regenerate tissue in the body.

Secondary Flows and Boundary-Layer Accumulations in Turbine Nozzles

NASA Technical Reports Server (NTRS)

Rohlik, Harold E; Kofskey, Milton G; Allen, Hubert W; Herzig, Howard Z

1954-01-01

An investigation of secondary-flow loss patterns originating in three sets of turbine nozzle blade passages was conducted by means of flow-visualization studies and detailed flow measurements. For all cases, high loss values were measured in the fluid downstream of the corners formed by the suction surfaces of the blades and the shrouds, and these losses were accompanied by discharge-angle deviations from design values. Despite the size of the loss regions and angle gradients, over-all mass-average blade efficiencies were of the order of 0.99 and 0.98 and, therefore, are not a good index of blade performance.

Development, optimization and evaluation of curcumin loaded biodegradable crosslinked gelatin film for the effective treatment of periodontitis.

PubMed

Chauhan, Sheetal; Bansal, Monika; Khan, Gayasuddin; Yadav, Sarita K; Singh, Ashish K; Prakash, Pradyot; Mishra, Brahmeshwar

2018-07-01

Aim of the present study was to prepare curcumin (CUR) loaded biodegradable crosslinked gelatin (GE) film to alleviate the existing shortcomings in the treatment of periodontitis. Gelatin film was optimized to provide anticipated mucoadhesive strength, mechanical properties, folding endurance, and prolonged drug release over treatment duration, for successful application in the periodontitis. The film was developed by using solvent casting technique and "Design of Experiments" approach was employed for evaluating the influence of independent variables on dependent response variables. Solid-state characterization of the film was performed by FTIR, XRD, and SEM. Further, prepared formulations were evaluated for drug content uniformity, surface pH, folding endurance, swelling index, mechanical strength, mucoadhesive strength, in vitro biodegradation, and in vitro drug release behavior. Solid state characterization of the formulation showed that CUR is physico-chemically compatible with other excipients and CUR was entrapped in an amorphous form inside the smooth and uniform film. The optimized film showed degree of crosslinking 51.04 ± 2.4, swelling index 138.10 ± 1.25, and folding endurance 270 ± 3 with surface pH around 7.0. Crosslinker concentrations positively affected swelling index and biodegradation of film due to altered matrix density of the polymer. Results of in vitro drug release demonstrated the capability of the developed film for efficiently delivering CUR in a sustained manner up to 7 days. The developed optimized film could be considered as a promising delivery strategy to administer medicament locally into the periodontal pockets for the safe and efficient management of periodontitis.

Development of a 3D finite element acoustic model to predict the sound reduction index of stud based double-leaf walls

NASA Astrophysics Data System (ADS)

Arjunan, A.; Wang, C. J.; Yahiaoui, K.; Mynors, D. J.; Morgan, T.; Nguyen, V. B.; English, M.

2014-11-01

Building standards incorporating quantitative acoustical criteria to ensure adequate sound insulation are now being implemented. Engineers are making great efforts to design acoustically efficient double-wall structures. Accordingly, efficient simulation models to predict the acoustic insulation of double-leaf wall structures are needed. This paper presents the development of a numerical tool that can predict the frequency dependent sound reduction index R of stud based double-leaf walls at one-third-octave band frequency range. A fully vibro-acoustic 3D model consisting of two rooms partitioned using a double-leaf wall, considering the structure and acoustic fluid coupling incorporating the existing fluid and structural solvers are presented. The validity of the finite element (FE) model is assessed by comparison with experimental test results carried out in a certified laboratory. Accurate representation of the structural damping matrix to effectively predict the R values are studied. The possibilities of minimising the simulation time using a frequency dependent mesh model was also investigated. The FEA model presented in this work is capable of predicting the weighted sound reduction index Rw along with A-weighted pink noise C and A-weighted urban noise Ctr within an error of 1 dB. The model developed can also be used to analyse the acoustically induced frequency dependent geometrical behaviour of the double-leaf wall components to optimise them for best acoustic performance. The FE modelling procedure reported in this paper can be extended to other building components undergoing fluid-structure interaction (FSI) to evaluate their acoustic insulation.

Actigraphic sleep measures and diet quality in the Hispanic Community Health Study/Study of Latinos Sueño ancillary study.

PubMed

Mossavar-Rahmani, Yasmin; Weng, Jia; Wang, Rui; Shaw, Pamela A; Jung, Molly; Sotres-Alvarez, Daniela; Castañeda, Sheila F; Gallo, Linda C; Gellman, Marc D; Qi, Qibin; Ramos, Alberto R; Reid, Kathryn J; Van Horn, Linda; Patel, Sanjay R

2017-12-01

Using a cross-sectional probability sample with actigraphy data and two 24-h dietary recalls, we quantified the association between sleep duration, continuity, variability and timing with the Alternative Healthy Eating Index-2010 diet quality score and its components in 2140 Hispanic Community Health Study/Study of Latinos participants. The Alternative Healthy Eating Index diet quality-2010 score ranges from 0 to 110, with higher scores indicating greater adherence to the dietary guidelines and lower risk from major chronic disease. None of the sleep measures was associated with total caloric intake as assessed using dietary recalls. However, both an increase in sleep duration and sleep efficiency were associated with healthier diet quality. Each standard deviation increase in sleep duration (1.05 h) and sleep efficiency (4.99%) was associated with a 0.30 point increase and 0.28 point increase, respectively, in the total Alternative Healthy Eating Index-2010 score. The component of Alternative Healthy Eating Index-2010 most strongly associated with longer sleep duration was increased nuts and legumes intake. The components of Alternative Healthy Eating Index-2010 most strongly associated with higher sleep efficiency were increased whole fruit intake and decreased sodium intake. Both longer sleep duration and higher sleep efficiency were significantly associated with better diet quality among US Hispanic/Latino adults. The dietary components most strongly associated with sleep duration and sleep efficiency differed, suggesting potentially independent mechanisms by which each aspect of sleep impacts dietary choices. Longitudinal research is needed to understand the directionality of these identified relationships and the generalizability of these data across other ethnic groups. © 2017 European Sleep Research Society.

Multi-parameter optimization of piezoelectric actuators for multi-mode active vibration control of cylindrical shells

NASA Astrophysics Data System (ADS)

Hu, K. M.; Li, Hua

2018-07-01

A novel technique for the multi-parameter optimization of distributed piezoelectric actuators is presented in this paper. The proposed method is designed to improve the performance of multi-mode vibration control in cylindrical shells. The optimization parameters of actuator patch configuration include position, size, and tilt angle. The modal control force of tilted orthotropic piezoelectric actuators is derived and the multi-parameter cylindrical shell optimization model is established. The linear quadratic energy index is employed as the optimization criterion. A geometric constraint is proposed to prevent overlap between tilted actuators, which is plugged into a genetic algorithm to search the optimal configuration parameters. A simply-supported closed cylindrical shell with two actuators serves as a case study. The vibration control efficiencies of various parameter sets are evaluated via frequency response and transient response simulations. The results show that the linear quadratic energy indexes of position and size optimization decreased by 14.0% compared to position optimization; those of position and tilt angle optimization decreased by 16.8%; and those of position, size, and tilt angle optimization decreased by 25.9%. It indicates that, adding configuration optimization parameters is an efficient approach to improving the vibration control performance of piezoelectric actuators on shells.

Genetic variation, population structure and linkage disequilibrium in Switchgrass with ISSR, SCoT and EST-SSR markers.

PubMed

Zhang, Yu; Yan, Haidong; Jiang, Xiaomei; Wang, Xiaoli; Huang, Linkai; Xu, Bin; Zhang, Xinquan; Zhang, Lexin

2016-01-01

To evaluate genetic variation, population structure, and the extent of linkage disequilibrium (LD), 134 switchgrass ( Panicum virgatum L.) samples were analyzed with 51 markers, including 16 ISSRs, 20 SCoTs, and 15 EST-SSRs. In this study, a high level of genetic variation was observed in the switchgrass samples and they had an average Nei's gene diversity index (H) of 0.311. A total of 793 bands were obtained, of which 708 (89.28 %) were polymorphic. Using a parameter marker index (MI), the efficiency of the three types of markers (ISSR, SCoT, and EST-SSR) in the study were compared and we found that SCoT had a higher marker efficiency than the other two markers. The 134 switchgrass samples could be divided into two sub-populations based on STRUCTURE, UPGMA clustering, and principal coordinate analyses (PCA), and upland and lowland ecotypes could be separated by UPGMA clustering and PCA analyses. Linkage disequilibrium analysis revealed an average r 2 of 0.035 across all 51 markers, indicating a trend of higher LD in sub-population 2 than that in sub-population 1 ( P  < 0.01). The population structure revealed in this study will guide the design of future association studies using these switchgrass samples.

miBLAST: scalable evaluation of a batch of nucleotide sequence queries with BLAST

PubMed Central

Kim, You Jung; Boyd, Andrew; Athey, Brian D.; Patel, Jignesh M.

2005-01-01

A common task in many modern bioinformatics applications is to match a set of nucleotide query sequences against a large sequence dataset. Exis-ting tools, such as BLAST, are designed to evaluate a single query at a time and can be unacceptably slow when the number of sequences in the query set is large. In this paper, we present a new algorithm, called miBLAST, that evaluates such batch workloads efficiently. At the core, miBLAST employs a q-gram filtering and an index join for efficiently detecting similarity between the query sequences and database sequences. This set-oriented technique, which indexes both the query and the database sets, results in substantial performance improvements over existing methods. Our results show that miBLAST is significantly faster than BLAST in many cases. For example, miBLAST aligned 247 965 oligonucleotide sequences in the Affymetrix probe set against the Human UniGene in 1.26 days, compared with 27.27 days with BLAST (an improvement by a factor of 22). The relative performance of miBLAST increases for larger word sizes; however, it decreases for longer queries. miBLAST employs the familiar BLAST statistical model and output format, guaranteeing the same accuracy as BLAST and facilitating a seamless transition for existing BLAST users. PMID:16061938

Blood flow dynamic improvement with aneurysm repair detected by a patient-specific model of multiple aortic aneurysms.

PubMed

Sughimoto, Koichi; Takahara, Yoshiharu; Mogi, Kenji; Yamazaki, Kenji; Tsubota, Ken'ichi; Liang, Fuyou; Liu, Hao

2014-05-01

Aortic aneurysms may cause the turbulence of blood flow and result in the energy loss of the blood flow, while grafting of the dilated aorta may ameliorate these hemodynamic disturbances, contributing to the alleviation of the energy efficiency of blood flow delivery. However, evaluating of the energy efficiency of blood flow in an aortic aneurysm has been technically difficult to estimate and not comprehensively understood yet. We devised a multiscale computational biomechanical model, introducing novel flow indices, to investigate a single male patient with multiple aortic aneurysms. Preoperative levels of wall shear stress and oscillatory shear index (OSI) were elevated but declined after staged grafting procedures: OSI decreased from 0.280 to 0.257 (first operation) and 0.221 (second operation). Graftings may strategically counter the loss of efficient blood delivery to improve hemodynamics of the aorta. The energy efficiency of blood flow also improved postoperatively. Novel indices of pulsatile pressure index (PPI) and pulsatile energy loss index (PELI) were evaluated to characterize and quantify energy loss of pulsatile blood flow. Mean PPI decreased from 0.445 to 0.423 (first operation) and 0.359 (second operation), respectively; while the preoperative PELI of 0.986 dropped to 0.820 and 0.831. Graftings contributed not only to ameliorate wall shear stress or oscillatory shear index but also to improve efficient blood flow. This patient-specific modeling will help in analyzing the mechanism of aortic aneurysm formation and may play an important role in quantifying the energy efficiency or loss in blood delivery.

Fast and efficient indexing approach for object recognition

NASA Astrophysics Data System (ADS)

Hefnawy, Alaa; Mashali, Samia A.; Rashwan, Mohsen; Fikri, Magdi

1999-08-01

This paper introduces a fast and efficient indexing approach for both 2D and 3D model-based object recognition in the presence of rotation, translation, and scale variations of objects. The indexing entries are computed after preprocessing the data by Haar wavelet decomposition. The scheme is based on a unified image feature detection approach based on Zernike moments. A set of low level features, e.g. high precision edges, gray level corners, are estimated by a set of orthogonal Zernike moments, calculated locally around every image point. A high dimensional, highly descriptive indexing entries are then calculated based on the correlation of these local features and employed for fast access to the model database to generate hypotheses. A list of the most candidate models is then presented by evaluating the hypotheses. Experimental results are included to demonstrate the effectiveness of the proposed indexing approach.

Optimizing plasmonic nanoantennas via coordinated multiple coupling

NASA Astrophysics Data System (ADS)

Lin, Linhan; Zheng, Yuebing

2015-10-01

Plasmonic nanoantennas, which can efficiently convert light from free space into sub-wavelength scale with the local field enhancement, are fundamental building blocks for nanophotonic systems. Predominant design methods, which exploit a single type of near- or far-field coupling in pairs or arrays of plasmonic nanostructures, have limited the tunability of spectral response and the local field enhancement. To overcome this limit, we are developing a general strategy towards exploiting the coordinated effects of multiple coupling. Using Au bowtie nanoantenna arrays with metal-insulator-metal configuration as examples, we numerically demonstrate that coordinated design and implementation of various optical coupling effects leads to both the increased tunability in the spectral response and the significantly enhanced electromagnetic field. Furthermore, we design and analyze a refractive index sensor with an ultra-high figure-of-merit (254), a high signal-to-noise ratio and a wide working range of refractive indices, and a narrow-band near-infrared plasmonic absorber with 100% absorption efficiency, high quality factor of up to 114 and a wide range of tunable wavelength from 800 nm to 1,500 nm. The plasmonic nanoantennas that exploit coordinated multiple coupling will benefit a broad range of applications, including label-free bio-chemical detection, reflective filter, optical trapping, hot-electron generation, and heat-assisted magnetic recording.

A Hybrid Spatio-Temporal Data Indexing Method for Trajectory Databases

PubMed Central

Ke, Shengnan; Gong, Jun; Li, Songnian; Zhu, Qing; Liu, Xintao; Zhang, Yeting

2014-01-01

In recent years, there has been tremendous growth in the field of indoor and outdoor positioning sensors continuously producing huge volumes of trajectory data that has been used in many fields such as location-based services or location intelligence. Trajectory data is massively increased and semantically complicated, which poses a great challenge on spatio-temporal data indexing. This paper proposes a spatio-temporal data indexing method, named HBSTR-tree, which is a hybrid index structure comprising spatio-temporal R-tree, B*-tree and Hash table. To improve the index generation efficiency, rather than directly inserting trajectory points, we group consecutive trajectory points as nodes according to their spatio-temporal semantics and then insert them into spatio-temporal R-tree as leaf nodes. Hash table is used to manage the latest leaf nodes to reduce the frequency of insertion. A new spatio-temporal interval criterion and a new node-choosing sub-algorithm are also proposed to optimize spatio-temporal R-tree structures. In addition, a B*-tree sub-index of leaf nodes is built to query the trajectories of targeted objects efficiently. Furthermore, a database storage scheme based on a NoSQL-type DBMS is also proposed for the purpose of cloud storage. Experimental results prove that HBSTR-tree outperforms TB*-tree in some aspects such as generation efficiency, query performance and query type. PMID:25051028

A hybrid spatio-temporal data indexing method for trajectory databases.

PubMed

Ke, Shengnan; Gong, Jun; Li, Songnian; Zhu, Qing; Liu, Xintao; Zhang, Yeting

2014-07-21

In recent years, there has been tremendous growth in the field of indoor and outdoor positioning sensors continuously producing huge volumes of trajectory data that has been used in many fields such as location-based services or location intelligence. Trajectory data is massively increased and semantically complicated, which poses a great challenge on spatio-temporal data indexing. This paper proposes a spatio-temporal data indexing method, named HBSTR-tree, which is a hybrid index structure comprising spatio-temporal R-tree, B*-tree and Hash table. To improve the index generation efficiency, rather than directly inserting trajectory points, we group consecutive trajectory points as nodes according to their spatio-temporal semantics and then insert them into spatio-temporal R-tree as leaf nodes. Hash table is used to manage the latest leaf nodes to reduce the frequency of insertion. A new spatio-temporal interval criterion and a new node-choosing sub-algorithm are also proposed to optimize spatio-temporal R-tree structures. In addition, a B*-tree sub-index of leaf nodes is built to query the trajectories of targeted objects efficiently. Furthermore, a database storage scheme based on a NoSQL-type DBMS is also proposed for the purpose of cloud storage. Experimental results prove that HBSTR-tree outperforms TB*-tree in some aspects such as generation efficiency, query performance and query type.

Environmental Quality Index webinar

EPA Pesticide Factsheets

Environmental Quality index, data reduction approaches to help improve statistical efficiency, summarizing information on the wider environment humans are exposed to. air, water, land, built, socio-demographic, human and environmental health

Empirical Study on Total Factor Productive Energy Efficiency in Beijing-Tianjin-Hebei Region-Analysis based on Malmquist Index and Window Model

NASA Astrophysics Data System (ADS)

Xu, Qiang; Ding, Shuai; An, Jingwen

2017-12-01

This paper studies the energy efficiency of Beijing-Tianjin-Hebei region and to finds out the trend of energy efficiency in order to improve the economic development quality of Beijing-Tianjin-Hebei region. Based on Malmquist index and window analysis model, this paper estimates the total factor energy efficiency in Beijing-Tianjin-Hebei region empirically by using panel data in this region from 1991 to 2014, and provides the corresponding political recommendations. The empirical result shows that, the total factor energy efficiency in Beijing-Tianjin-Hebei region increased from 1991 to 2014, mainly relies on advances in energy technology or innovation, and obvious regional differences in energy efficiency to exist. Throughout the window period of 24 years, the regional differences of energy efficiency in Beijing-Tianjin-Hebei region shrank. There has been significant convergent trend in energy efficiency after 2000, mainly depends on the diffusion and spillover of energy technologies.

High efficient light absorption and nanostructure-dependent birefringence of a metal-dielectric symmetrical layered structure

NASA Astrophysics Data System (ADS)

Jen, Yi-Jun; Jhang, Yi-Ciang; Liu, Wei-Chih

2017-08-01

A multilayer that comprises ultra-thin metal and dielectric films has been investigated and applied as a layered metamaterial. By arranging metal and dielectric films alternatively and symmetrically, the equivalent admittance and refractive index can be tailored separately. The tailored admittance and refractive index enable us to design optical filters with more flexibility. The admittance matching is achieved via the admittance tracing in the normalized admittance diagram. In this work, an ultra-thin light absorber is designed as a multilayer composed of one or several cells. Each cell is a seven-layered film stack here. The design concept is to have the extinction as large as possible under the condition of admittance matching. For a seven-layered symmetrical film stack arranged as Ta2O5 (45 nm)/ a-Si (17 nm)/ Cr (30 nm)/ Al (30 nm)/ Cr (30 nm)/ a-Si (17 nm)/ Ta2O5 (45 nm), its mean equivalent admittance and extinction coefficient over the visible regime is 1.4+0.2i and 2.15, respectively. The unit cell on a transparent BK7 glass substrate absorbs 99% of normally incident light energy for the incident medium is glass. On the other hand, a transmission-induced metal-dielectric film stack is investigated by using the admittance matching method. The equivalent anisotropic property of the metal-dielectric multilayer varied with wavelength and nanostructure are investigated here.

Analysis of different image-based biofeedback models for improving cycling performances

NASA Astrophysics Data System (ADS)

Bibbo, D.; Conforto, S.; Bernabucci, I.; Carli, M.; Schmid, M.; D'Alessio, T.

2012-03-01

Sport practice can take advantage from the quantitative assessment of task execution, which is strictly connected to the implementation of optimized training procedures. To this aim, it is interesting to explore the effectiveness of biofeedback training techniques. This implies a complete chain for information extraction containing instrumented devices, processing algorithms and graphical user interfaces (GUIs) to extract valuable information (i.e. kinematics, dynamics, and electrophysiology) to be presented in real-time to the athlete. In cycling, performance indexes displayed in a simple and perceivable way can help the cyclist optimize the pedaling. To this purpose, in this study four different GUIs have been designed and used in order to understand if and how a graphical biofeedback can influence the cycling performance. In particular, information related to the mechanical efficiency of pedaling is represented in each of the designed interfaces and then displayed to the user. This index is real-time calculated on the basis of the force signals exerted on the pedals during cycling. Instrumented pedals for bikes, already designed and implemented in our laboratory, have been used to measure those force components. A group of subjects underwent an experimental protocol and pedaled with (the interfaces have been used in a randomized order) and without graphical biofeedback. Preliminary results show how the effective perception of the biofeedback influences the motor performance.

Index of Non-Government Standards on Human Engineering Design Criteria and Program Requirements/Guidelines. Version 3

DTIC Science & Technology

2002-10-01

the Seated Operator of Off-Highway Work Machines ♦ SAE J1013 1992 http://www.sae.org/servlets/ index http://standards.nasa.gov/NPTS/login.taf...Public Access permits users to view the NASA Preferred Technical Standards index , with the capability to download free of charge the NASA- Developed ...www.sae.org/servlets/ index http://www.techstreet.com/ Design of Ergonomic Requirements for the Design of Displays and Control Actuators -

A study on operation efficiency evaluation based on firm's financial index and benchmark selection: take China Unicom as an example

NASA Astrophysics Data System (ADS)

Wu, Zu-guang; Tian, Zhan-jun; Liu, Hui; Huang, Rui; Zhu, Guo-hua

2009-07-01

Being the only listed telecom operators of A share market, China Unicom has always been attracted many institutional investors under the concept of 3G recent years,which itself is a great technical progress expectation.Do the institutional investors or the concept of technical progress have signficant effect on the improving of firm's operating efficiency?Though reviewing the documentary about operating efficiency we find that schoolars study this problem useing the regress analyzing based on traditional production function and data envelopment analysis(DEA) and financial index anayzing and marginal function and capital labor ratio coefficient etc. All the methods mainly based on macrodata. This paper we use the micro-data of company to evaluate the operating efficiency.Using factor analyzing based on financial index and comparing the factor score of three years from 2005 to 2007, we find that China Unicom's operating efficiency is under the averge level of benchmark corporates and has't improved under the concept of 3G from 2005 to 2007.In other words,institutional investor or the conception of technical progress expectation have faint effect on the changes of China Unicom's operating efficiency. Selecting benchmark corporates as post to evaluate the operating efficiency is a characteristic of this method ,which is basicallly sipmly and direct.This method is suit for the operation efficiency evaluation of agriculture listed companies because agriculture listed also face technical progress and marketing concept such as tax-free etc.

Efficient Single-Pass Index Construction for Text Databases.

ERIC Educational Resources Information Center

Heinz, Steffen; Zobel, Justin

2003-01-01

Discusses index construction for text collections, reviews principal approaches to inverted indexes, analyzes their theoretical cost, and presents experimental results of the use of a single-pass inversion method on Web document collections. Shows that the single-pass approach is faster and does not require the complete vocabulary of the indexed…

Influence of panel fastening on the acoustic performance of light-weight building elements: Study by sound transmission and laser scanning vibrometry

NASA Astrophysics Data System (ADS)

Roozen, N. B.; Muellner, H.; Labelle, L.; Rychtáriková, M.; Glorieux, C.

2015-06-01

Structural details and workmanship can cause considerable differences in sound insulation properties of timber frame partitions. In this study, the influence of panel fastening is investigated experimentally by means of standardized sound reduction index measurements, supported by detailed scanning laser Doppler vibrometry. In particular the effect of the number of screws used to fasten the panels to the studs, and the tightness of the screws, is studied using seven different configurations of lightweight timber frame building elements. In the frequency range from 300 to 4000 Hz, differences in the weighted sound reduction index RW as large as 10 dB were measured, suggesting that the method of fastening can have a large impact on the acoustic performance of building elements. Using the measured vibrational responses of the element, its acoustic radiation efficiency was computed numerically by means of a Rayleigh integral. The increased radiation efficiency partly explains the reduced sound reduction index. Loosening the screws, or reducing the number of screws, lowers the radiation efficiency, and significantly increases the sound reduction index of the partition.

Method and system for efficiently searching an encoded vector index

DOEpatents

Bui, Thuan Quang; Egan, Randy Lynn; Kathmann, Kevin James

2001-09-04

Method and system aspects for efficiently searching an encoded vector index are provided. The aspects include the translation of a search query into a candidate bitmap, and the mapping of data from the candidate bitmap into a search result bitmap according to entry values in the encoded vector index. Further, the translation includes the setting of a bit in the candidate bitmap for each entry in a symbol table that corresponds to candidate of the search query. Also included in the mapping is the identification of a bit value in the candidate bitmap pointed to by an entry in an encoded vector.

A novel concentrator with zero-index metamaterial for space solar power station

NASA Astrophysics Data System (ADS)

Huang, Jin; Chu, Xue-mei; Fan, Jian-yu; Jin, Qi-bao; Duan, Zhu-zhu

2017-03-01

Space solar power station (SSPS) is a comprehensive system that continuously collects solar energy in space and transmits it to ground with a wireless power transmission (WPT) system. These systems have great potential to provide large-scale energy. To increase the efficiency and reduce the weight and cost of the photovoltaic (PV) components, a huge light-weighted concentrator was introduced in the latest SSPS concepts, such as integrated symmetrical concentrator (ISC) and arbitrarily large phased array (ALPHA). However, for typical SSPS running in Geostationary Earth Orbit (GEO), the sunlight direction varies with time, leading to a great challenge for concentrator design. In ISC, the two-dimensional mast is used to realize sun-tracking. However, a multi-thousand-ton structure is difficult to control precisely in space. For this reason, ALPHA comprises a large number of individually pointed thin-film reflectors to intercept sunlight, mounted on the non-moving structure. However, the real-time adjustment of the thousands of reflectors is still an open problem. Furthermore, the uniformity of the time of the power generation (UTPG) is another factor evaluating the system. Therefore, this paper proposes a novel concentrator based on zero-index metamaterial (ZIM) called Thin-film Energy Terminator (SSPS-TENT). This will aid the control of the massive reflectors while avoiding the rotation of the overall system, the control of the massive reflectors and the influence of the obliquity of the ecliptic. Also, an optimization design method is proposed to increase its solar energy collecting efficiency (ECE) and flux distribution (FD). The ray-tracing simulation results show that the ECE is more than 96% of the day. In terms of the FD, the uniformity varies from 0.3057 to 0.5748. Compared with ALPHA, the UTPG is more stable.

Vulnerability assessment in a participatory approach to design and implement community based adaptation to drought in the Peruvian Andes

NASA Astrophysics Data System (ADS)

Lasage, Ralph; Muis, Sanne; Sardella, Carolina; van Drunen, Michiel; Verburg, Peter; Aerts, Jeroen

2015-04-01

The livelihoods of people in the Andes are expected to be affected by climate change due to their dependence on glacier meltwater during the growing season. The observed decrease in glacier volume over the last few decades is likely to accelerate during the current century, which will affect water availability in the region. This paper presents the implementation of an approach for the participatory development of community-based adaptation measures to cope with the projected impacts of climate change, which was implemented jointly by the local community and by a team consisting of an NGO, Peruvian ministry of environment, research organisations and a private sector organisation. It bases participatory design on physical measurements, modelling and a vulnerability analysis. Vulnerability to drought is made operational for households in a catchment of the Ocoña river basin in Peru. On the basis of a household survey we explore how a vulnerability index (impacts divided by the households' perceived adaptive capacity) can be used to assess the distribution of vulnerability over households in a sub catchment. The socio-economic factors water entitlement, area of irrigated land, income and education are all significantly correlate with this vulnerability to drought. The index proved to be appropriate for communicating about vulnerability to climate change and its determining factors with different stakeholders. The water system research showed that the main source of spring water is local rainwater, and that water use efficiency in farming is low. The adaptation measures that were jointly selected by the communities and the project team aimed to increase water availability close to farmland, and increase water use efficiency, and these will help to reduce the communities vulnerability to drought.

Principle and engineering implementation of 3D visual representation and indexing of medical diagnostic records (Conference Presentation)

NASA Astrophysics Data System (ADS)

Shi, Liehang; Sun, Jianyong; Yang, Yuanyuan; Ling, Tonghui; Wang, Mingqing; Zhang, Jianguo

2017-03-01

Purpose: Due to the generation of a large number of electronic imaging diagnostic records (IDR) year after year in a digital hospital, The IDR has become the main component of medical big data which brings huge values to healthcare services, professionals and administration. But a large volume of IDR presented in a hospital also brings new challenges to healthcare professionals and services as there may be too many IDRs for each patient so that it is difficult for a doctor to review all IDR of each patient in a limited appointed time slot. In this presentation, we presented an innovation method which uses an anatomical 3D structure object visually to represent and index historical medical status of each patient, which is called Visual Patient (VP) in this presentation, based on long term archived electronic IDR in a hospital, so that a doctor can quickly learn the historical medical status of the patient, quickly point and retrieve the IDR he or she interested in a limited appointed time slot. Method: The engineering implementation of VP was to build 3D Visual Representation and Index system called VP system (VPS) including components of natural language processing (NLP) for Chinese, Visual Index Creator (VIC), and 3D Visual Rendering Engine.There were three steps in this implementation: (1) an XML-based electronic anatomic structure of human body for each patient was created and used visually to index the all of abstract information of each IDR for each patient; (2)a number of specific designed IDR parsing processors were developed and used to extract various kinds of abstract information of IDRs retrieved from hospital information systems; (3) a 3D anatomic rendering object was introduced visually to represent and display the content of VIO for each patient. Results: The VPS was implemented in a simulated clinical environment including PACS/RIS to show VP instance to doctors. We setup two evaluation scenario in a hospital radiology department to evaluate whether radiologists accept the VPS and how the VP impact the radiologists' efficiency and accuracy in reviewing historic medical records of the patients. We got a statistical results showing that more than 70% participated radiologist would like to use the VPS in their radiological imaging services. In comparison testing of using VPS and RIS/PACS in reviewing historic medical records of the patients, we got a statistical result showing that the efficiency of using VPS was higher than that of using PACS/RIS. New Technologies and Results to be presented: This presentation presented an innovation method to use an anatomical 3D structure object, called VP, visually to represent and index historical medical records such as IDR of each patient and a doctor can quickly learn the historical medical status of the patient through VPS. The evaluation results showed that VPS has better performance than RIS-integrated PACS in efficiency of reviewing historic medical records of the patients. Conclusions: In this presentation, we presented an innovation method called VP to use an anatomical 3D structure object visually to represent and index historical IDR of each patient and briefed an engineering implementation to build a VPS to implement the major features and functions of VP. We setup two evaluation scenarios in a hospital radiology department to evaluate VPS and achieved evaluation results showed that VPS has better performance than RIS-integrated PACS in efficiency of reviewing historic medical records of the patients.

Cos-Gaussian modal field of a terahertz rectangular metal waveguide filled with multiple slices of dielectric

NASA Astrophysics Data System (ADS)

Wang, Kai; Cao, Qing; Zhang, Huifang; Shen, Pengcheng; Xing, Lujing

2018-06-01

Based on the TE01 mode of a rectangular metal waveguide and the Gaussian mode of a fiber, we propose the cos-Gaussian mode of a terahertz rectangular metal waveguide filled with multiple slices of dielectric. First, we consider a rectangular metal waveguide filled with an ideal graded-index dielectric along one direction. Furthermore, we replace the graded-index dielectric with multiple slices of dielectric according to the effective medium theory. The modal field, the effective index, and the coupling efficiency of this waveguide are investigated. It is found that the approximately linearly polarized electric field is Gaussian along one dimensionality and cosine along the other one. In addition, the low loss and high coupling efficiency with a Gaussian beam can be acquired at 0.9 THz. By optimization, the coupling efficiency could reach 88.5%.

Hybrid photonic crystal cavity and waveguide for coupling to diamond NV-centers.

PubMed

Barclay, Paul E; Fu, Kai-Mei; Santori, Charles; Beausoleil, Raymond G

2009-06-08

A design for an ultra-high Q photonic crystal nanocavity engineered to interact with nitrogen-vacancy (NV) centers located near the surface of a single crystal diamond sample is presented. The structure is based upon a nanowire photonic crystal geometry, and consists of a patterned high refractive index thin film, such as gallium phosphide (GaP), supported by a diamond substrate. The nanocavity supports a mode with quality factor Q > 1.5 x 10(6) and mode volume V < 0.52(lambda/nGaP)(3), and promises to allow Purcell enhanced collection of spontaneous emission from an NV located more than 50 nm below the diamond surface. The nanowire photonic crystal waveguide can be used to efficiently couple light into and out of the cavity, or as an efficient broadband collector of NV phonon sideband emission. The proposed structures can be fabricated using existing materials and processing techniques.

Evaluation of Eco-Efficiency and Performance of Retrofit Materials

NASA Astrophysics Data System (ADS)

Gopinath, Smitha; Rama Chandra Murthy, A.; Iyer, Nagesh R.; Kokila, S.

2015-12-01

In this work three materials namely Fiber Reinforced Polymer (FRP), ferrocement and Textile Reinforced Concrete (TRC) have been evaluated towards their performance efficiency and eco-effectiveness for sustainable retrofitting applications. Investigations have been carried out for flexural strengthening of RC beams with FRP, ferrocement and TRC. It is observed that in the case of FRP, it is not possible to tailor the material according to design requirements and most of the time strengthened structure becomes over stiff. Eco-effectiveness of these retrofitting materials has been evaluated by computing the embodied energy. It is observed that the amount of CO2 emitted by TRC is less compared to other retrofit materials. Further, the performance point of retrofitted RC frames has been evaluated and damage index has been calculated to find out the effective retrofit material. It is concluded that, if RC frame is retrofitted with FRP and TRC, it undergoes less damage compared to ferrocement.

An intelligent healthcare management system: a new approach in work-order prioritization for medical equipment maintenance requests.

PubMed

Hamdi, Naser; Oweis, Rami; Abu Zraiq, Hamzeh; Abu Sammour, Denis

2012-04-01

The effective maintenance management of medical technology influences the quality of care delivered and the profitability of healthcare facilities. Medical equipment maintenance in Jordan lacks an objective prioritization system; consequently, the system is not sensitive to the impact of equipment downtime on patient morbidity and mortality. The current work presents a novel software system (EQUIMEDCOMP) that is designed to achieve valuable improvements in the maintenance management of medical technology. This work-order prioritization model sorts medical maintenance requests by calculating a priority index for each request. Model performance was assessed by utilizing maintenance requests from several Jordanian hospitals. The system proved highly efficient in minimizing equipment downtime based on healthcare delivery capacity, and, consequently, patient outcome. Additionally, a preventive maintenance optimization module and an equipment quality control system are incorporated. The system is, therefore, expected to improve the reliability of medical equipment and significantly improve safety and cost-efficiency.

Sub-50-nm self-assembled nanotextures for enhanced broadband antireflection in silicon solar cells.

PubMed

Rahman, Atikur; Ashraf, Ahsan; Xin, Huolin; Tong, Xiao; Sutter, Peter; Eisaman, Matthew D; Black, Charles T

2015-01-21

Materials providing broadband light antireflection have applications as highly transparent window coatings, military camouflage, and coatings for efficiently coupling light into solar cells and out of light-emitting diodes. In this work, densely packed silicon nanotextures with feature sizes smaller than 50 nm enhance the broadband antireflection compared with that predicted by their geometry alone. A significant fraction of the nanotexture volume comprises a surface layer whose optical properties differ substantially from those of the bulk, providing the key to improved performance. The nanotexture reflectivity is quantitatively well-modelled after accounting for both its profile and changes in refractive index at the surface. We employ block copolymer self-assembly for precise and tunable nanotexture design in the range of ~10-70 nm across macroscopic solar cell areas. Implementing this efficient antireflection approach in crystalline silicon solar cells significantly betters the performance gain compared with an optimized, planar antireflection coating.

Protection of electronic health records (EHRs) in cloud.

PubMed

Alabdulatif, Abdulatif; Khalil, Ibrahim; Mai, Vu

2013-01-01

EHR technology has come into widespread use and has attracted attention in healthcare institutions as well as in research. Cloud services are used to build efficient EHR systems and obtain the greatest benefits of EHR implementation. Many issues relating to building an ideal EHR system in the cloud, especially the tradeoff between flexibility and security, have recently surfaced. The privacy of patient records in cloud platforms is still a point of contention. In this research, we are going to improve the management of access control by restricting participants' access through the use of distinct encrypted parameters for each participant in the cloud-based database. Also, we implement and improve an existing secure index search algorithm to enhance the efficiency of information control and flow through a cloud-based EHR system. At the final stage, we contribute to the design of reliable, flexible and secure access control, enabling quick access to EHR information.

Sleep and daytime sleepiness of patients with left ventricular assist devices: a longitudinal pilot study.

PubMed

Casida, Jesus M; Davis, Jean E; Brewer, Robert J; Smith, Cheryl; Yarandi, Hossein

2011-06-01

No empirical longitudinal data on sleep and daytime sleepiness patterns in patients with an implantable left ventricular assist device (LVAD) exist. (1) To describe the sleep patterns (sleep onset latency, sleep efficiency, sleep fragmentation index, total sleep time, and wake after sleep onset), sleep quality, and daytime sleepiness variables and (2) to determine the change in the pattern of these variables before and up to 6 months after LVAD implantation. A longitudinal descriptive repeated-measures design was used. Patients wore wrist actigraphs (AW64 Actiwatch), which objectively measured sleep, for 3 consecutive days and nights before LVAD implant and at the first and second week and first, third, and sixth month after implantation. During these periods, patients also completed questionnaires on sleep quality and daytime sleepiness. Patients-Twelve of 15 patients completed the 6-month data. Data were analyzed by using descriptive statistics and repeated-measures analysis of variance. We found long sleep onset latencies and low sleep efficiency across time periods. High sleep fragmentation index was noted at baseline and 1 week after LVAD. Short total sleep times, long wake-after-sleep-onset durations, and poor sleep quality were evident at baseline and persisted up to 6 months after LVAD implantation. Low alertness level, a manifestation of sleepiness, was common during late morning to early evening hours. However, only sleep efficiency and wake after sleep onset showed significant changes in pattern (P < .05). Sleep disturbance and daytime sleepiness may be prevalent before and up to 6 months after LVAD implantation, warranting further investigation.

Numerical Investigation of the Influence of Blade Radial Gap Flow on Axial Blood Pump Performance.

PubMed

Liu, Guang-Mao; Jin, Dong-Hai; Zhou, Jian-Ye; Zhang, Yan; Chen, Hai-Bo; Sun, Han-Song; Hu, Sheng-Shou; Gui, Xing-Min

2018-01-05

The gaps between the blades and the shroud (or hub) of an axial blood pump affect the hydraulics, efficiency, and hemolytic performance. These gaps are critical parameters when a blood pump is manufactured. To evaluate the influence of blade gaps on axial blood pump performance, the flow characteristics inside an axial blood pump with different radial blade gaps were numerically simulated and analyzed with special attention paid to the hydraulic characteristics, gap flow, hydraulic efficiency, and hemolysis index (HI). In vitro hydraulic testing and particle image velocimetry testing were conducted to verify the numerical results. The simulation results showed that the efficiency and pressure rise decreased when the gap increased. The efficiency of the axial blood pump at design point decreased from 37.1% to 27.1% and the pressure rise decreased from 127.4 to 71.2 mm Hg when the gap increased from 0.1 to 0.3 mm. Return and vortex flows were present in the outlet guide vane channels when the gap was larger than 0.2 mm. The HI of the blood pump with a 0.1 mm gap was 1.5-fold greater than that with a 0.3 mm gap. The results illustrated poor hydraulic characteristics when the gap was larger than 0.15 mm and rapidly deteriorated hemolysis when the gap was larger than 0.1 mm. The numerical and experimental results demonstrated that the pressure rise, pump efficiency, and scalar shear stress decreased when the gap increased. The HI did not strictly decrease with gap increases. The preliminary results encourage the improvement of axial blood pump designs.

Structural Reliability Analysis and Optimization: Use of Approximations

NASA Technical Reports Server (NTRS)

Grandhi, Ramana V.; Wang, Liping

1999-01-01

This report is intended for the demonstration of function approximation concepts and their applicability in reliability analysis and design. Particularly, approximations in the calculation of the safety index, failure probability and structural optimization (modification of design variables) are developed. With this scope in mind, extensive details on probability theory are avoided. Definitions relevant to the stated objectives have been taken from standard text books. The idea of function approximations is to minimize the repetitive use of computationally intensive calculations by replacing them with simpler closed-form equations, which could be nonlinear. Typically, the approximations provide good accuracy around the points where they are constructed, and they need to be periodically updated to extend their utility. There are approximations in calculating the failure probability of a limit state function. The first one, which is most commonly discussed, is how the limit state is approximated at the design point. Most of the time this could be a first-order Taylor series expansion, also known as the First Order Reliability Method (FORM), or a second-order Taylor series expansion (paraboloid), also known as the Second Order Reliability Method (SORM). From the computational procedure point of view, this step comes after the design point identification; however, the order of approximation for the probability of failure calculation is discussed first, and it is denoted by either FORM or SORM. The other approximation of interest is how the design point, or the most probable failure point (MPP), is identified. For iteratively finding this point, again the limit state is approximated. The accuracy and efficiency of the approximations make the search process quite practical for analysis intensive approaches such as the finite element methods; therefore, the crux of this research is to develop excellent approximations for MPP identification and also different approximations including the higher-order reliability methods (HORM) for representing the failure surface. This report is divided into several parts to emphasize different segments of the structural reliability analysis and design. Broadly, it consists of mathematical foundations, methods and applications. Chapter I discusses the fundamental definitions of the probability theory, which are mostly available in standard text books. Probability density function descriptions relevant to this work are addressed. In Chapter 2, the concept and utility of function approximation are discussed for a general application in engineering analysis. Various forms of function representations and the latest developments in nonlinear adaptive approximations are presented with comparison studies. Research work accomplished in reliability analysis is presented in Chapter 3. First, the definition of safety index and most probable point of failure are introduced. Efficient ways of computing the safety index with a fewer number of iterations is emphasized. In chapter 4, the probability of failure prediction is presented using first-order, second-order and higher-order methods. System reliability methods are discussed in chapter 5. Chapter 6 presents optimization techniques for the modification and redistribution of structural sizes for improving the structural reliability. The report also contains several appendices on probability parameters.

Development of a prototype magnetically suspended rotor ventricular assist device.

PubMed

Bearnson, G B; Maslen, E H; Olsen, D B; Allaire, P E; Khanwilkar, P S; Long, J W; Kim, H C

1996-01-01

A continuous flow centrifugal blood pump with magnetically suspended impeller has been designed, constructed, and tested. The system can be functionally divided into three subsystem designs: 1) centrifugal pump and flow paths, 2) magnetic bearings, and 3) brushless DC motor. The centrifugal pump is a Francis vane type design with a designed operating point of 6 L/min flow and 100 mmHg pressure rise at 2,300 RPM. Peak hydraulic efficiency is over 50%. The magnetic bearing system is an all active design with five axes of control. Rotor position sensors were developed as part of the system to provide feedback to a proportional-integral-derivative controller. The motor is a sensorless brushless DC motor. Back electromotive force voltage generated by the motor is used to provide commutation for the motor. No slots are employed in the motor design in order to reduce the radial force that the bearings must generate. Tests pumping blood in vitro were very encouraging; an index of hemolysis of 0.0086 +/- 0.0012 was measured. Further design refinement is needed to reduce power dissipation and size of the device. The concept of using magnetic bearings in a blood pump shows promise in a long-term implantable blood pump.

Optical Coatings With Graded Index Layers For High Power Laser Applications: Design

NASA Astrophysics Data System (ADS)

Zukic, Muamer; Guenther, Karl H.

1988-06-01

Graded index layers provide a greater flexibility for the design of optical coatings than "homogeneous" layers. A graded index layer can replace the whole or a part of a traditional multilayer stack of alternating thin films of high and low refractive index. This paper presents design examples for broadband antireflection coatings, narrowband high reflectors (also referred to as minus filters or rejection line filters), and non-polarizing beam splitters. Optimized refractive index profiles are derived for broadband antireflection coatings for various combinations of incident medium and substrate. The rejection line filter example uses a sinusoidal (rugate) index profile. The non-polarizing beamsplitter summarizes the topical contents of a paper presented in another conference at the same symposium.

Provincial Human Development Index, a Guide for Efficiency Level Analysis: The Case of Iran

PubMed Central

SABERMAHANI, Asma; BAROUNI, Mohsen; SEYEDIN, Hesam; ARYANKHESAL, Aidin

2013-01-01

Background Human Development Index (HDI) is a composite indicator that can show the impact of economic strategies on human life standards. The index is calculated by three main factors of income, education and health. This research studies the status of HDI across the Iranian provinces, its changes over time and the efficiency of provinces in using resources. Methods: The data for 2001 and 2009 was obtained from the Iranian Center of Statistics. Data envelopment analysis technique was used to analyze the data. To calculate the efficiency, Banker, Charnes and Cooper’s model was used. Results: The national mean for the HDI in 2001 was 0.717 while it grew to 0.747 in 2009. Except for one province, all others had an improved human development index. Low ranked provinces such as Sistan & Baluchistan and Kurdistan stayed at the bottom in 2009 as well. Some provinces such as Bushehr with developing oil industries, or those purposively benefited from national oil income showed good growth. In some provinces, such as Hormozgan, out-migration of manpower to its neighboring province, Bushehr, was associated with decrease of the provincial income level. The number of efficient provinces increased from 5 to 13 in 2009. Conclusion: Iran falls among countries with high human development index based on the 2009 data. However, the distribution of HDI status across provinces was highly varied and the difference between high- and low-developed provinces increased in 2009. The government needs to revise policies concerning distribution of resources among the provinces. PMID:23515434

Domestic Banks in Bangladesh Could Ensure Efficiency by Improving Human Resource Management Practices

PubMed Central

Muhammad Masum, Abdul Kadar; Azad, Md. Abul Kalam; Hoque, Kazi Enamul; Beh, Loo-See

2015-01-01

The paper aims to examine the influence of human resource management (HRM) practices on bank efficiency using Malmquist index of total factor productivity. The model comprises HRM index that represents the quality of HRM practices. The results are decomposed into three efficiency scores, namely, technical efficiency, pure efficiency, and scale efficiency. In this study, panel data for 44 banks in Bangladesh are used for the period 2008-2013. This paper reveals that foreign banks are ahead in converting the influence of HRM practices into efficiency scores (0.946>0.833). On the other hand, domestic banks performed better than foreign banks in terms of pure efficiency and scale efficiency. But, in terms of technical efficiency, the domestic banks are regressed by 6.7% annually whereas foreign banks are progressed with a yearly value of 5.8%. The results are robust, because the Mann-Whitney test and Kruskall-Wallis test (non-parametric tests) also confirm the same results. This study emphasizes HRM practices in the banking industry to ensure efficiency in the long-term scenario. Domestic banks are suggested to ensure continuous development in HRM practices in order to compete with foreign banks. PMID:26221727

Domestic Banks in Bangladesh Could Ensure Efficiency by Improving Human Resource Management Practices.

PubMed

Masum, Abdul Kadar Muhammad; Azad, Md Abul Kalam; Hoque, Kazi Enamul; Beh, Loo-See

2015-01-01

The paper aims to examine the influence of human resource management (HRM) practices on bank efficiency using Malmquist index of total factor productivity. The model comprises HRM index that represents the quality of HRM practices. The results are decomposed into three efficiency scores, namely, technical efficiency, pure efficiency, and scale efficiency. In this study, panel data for 44 banks in Bangladesh are used for the period 2008-2013. This paper reveals that foreign banks are ahead in converting the influence of HRM practices into efficiency scores (0.946>0.833). On the other hand, domestic banks performed better than foreign banks in terms of pure efficiency and scale efficiency. But, in terms of technical efficiency, the domestic banks are regressed by 6.7% annually whereas foreign banks are progressed with a yearly value of 5.8%. The results are robust, because the Mann-Whitney test and Kruskall-Wallis test (non-parametric tests) also confirm the same results. This study emphasizes HRM practices in the banking industry to ensure efficiency in the long-term scenario. Domestic banks are suggested to ensure continuous development in HRM practices in order to compete with foreign banks.

VIEWCACHE: An incremental pointer-base access method for distributed databases. Part 1: The universal index system design document. Part 2: The universal index system low-level design document. Part 3: User's guide. Part 4: Reference manual. Part 5: UIMS test suite

NASA Technical Reports Server (NTRS)

Kelley, Steve; Roussopoulos, Nick; Sellis, Timos

1992-01-01

The goal of the Universal Index System (UIS), is to provide an easy-to-use and reliable interface to many different kinds of database systems. The impetus for this system was to simplify database index management for users, thus encouraging the use of indexes. As the idea grew into an actual system design, the concept of increasing database performance by facilitating the use of time-saving techniques at the user level became a theme for the project. This Final Report describes the Design, the Implementation of UIS, and its Language Interfaces. It also includes the User's Guide and the Reference Manual.

The role of effort in moderating the anxiety-performance relationship: Testing the prediction of processing efficiency theory in simulated rally driving.

PubMed

Wilson, Mark; Smith, Nickolas C; Chattington, Mark; Ford, Mike; Marple-Horvat, Dilwyn E

2006-11-01

We tested some of the key predictions of processing efficiency theory using a simulated rally driving task. Two groups of participants were classified as either dispositionally high or low anxious based on trait anxiety scores and trained on a simulated driving task. Participants then raced individually on two similar courses under counterbalanced experimental conditions designed to manipulate the level of anxiety experienced. The effort exerted on the driving tasks was assessed though self-report (RSME), psychophysiological measures (pupil dilation) and visual gaze data. Efficiency was measured in terms of efficiency of visual processing (search rate) and driving control (variability of wheel and accelerator pedal) indices. Driving performance was measured as the time taken to complete the course. As predicted, increased anxiety had a negative effect on processing efficiency as indexed by the self-report, pupillary response and variability of gaze data. Predicted differences due to dispositional levels of anxiety were also found in the driving control and effort data. Although both groups of drivers performed worse under the threatening condition, the performance of the high trait anxious individuals was affected to a greater extent by the anxiety manipulation than the performance of the low trait anxious drivers. The findings suggest that processing efficiency theory holds promise as a theoretical framework for examining the relationship between anxiety and performance in sport.

A fast sequence assembly method based on compressed data structures.

PubMed

Liang, Peifeng; Zhang, Yancong; Lin, Kui; Hu, Jinglu

2014-01-01

Assembling a large genome using next generation sequencing reads requires large computer memory and a long execution time. To reduce these requirements, a memory and time efficient assembler is presented from applying FM-index in JR-Assembler, called FMJ-Assembler, where FM stand for FMR-index derived from the FM-index and BWT and J for jumping extension. The FMJ-Assembler uses expanded FM-index and BWT to compress data of reads to save memory and jumping extension method make it faster in CPU time. An extensive comparison of the FMJ-Assembler with current assemblers shows that the FMJ-Assembler achieves a better or comparable overall assembly quality and requires lower memory use and less CPU time. All these advantages of the FMJ-Assembler indicate that the FMJ-Assembler will be an efficient assembly method in next generation sequencing technology.

LED pumped Nd:YAG laser development program

NASA Technical Reports Server (NTRS)

Farmer, G. I.; Kiang, Y. C.; Lynch, R. J.

1973-01-01

The results of a development program for light emitting diode (LED) pumped Nd:YAG lasers are described. An index matching method to increase the coupling efficiency of the laser is described. A solid glass half-cylinder of 5.0 by 5.6 centimeters was used for index matching and also as a pumping cavity reflector. The laser rods were 1.5 by 56 millimeters with dielectric coatings on both end surfaces. The interfaces between the diode array, glass cylinder, and laser rod were filled with viscous fluid of refractive index n = 1.55. Experiments performed with both the glass cylinder and a gold coated stainless steel reflector of the same dimensions under the same operating conditions indicate that the index matching cylinder gave 159 to 200 percent improvement of coupling efficiency over the metal reflector at various operating temperatures.

A randomised titrated crossover study comparing two oral appliances in the treatment for mild to moderate obstructive sleep apnoea/hypopnoea syndrome.

PubMed

Zhou, J; Liu, Y H

2012-12-01

The objective of this study was to compare the efficiency of two oral appliances in patients with mild to moderate obstructive sleep apnoea/hypopnoea syndrome (OSAHS) by the analysis of objective and subjective evaluations and measurement of upper airway parameter. A randomised crossover design trial was carried out on 16 patients with OSAHS. Two different types of oral appliances were tested in each patient, a one-piece monoblock and the SILENT NITE(®) (GlideWell Laboratories, Newport Beach, CA, USA), a two-piece appliance. Each oral appliance needed to be worn for two 3-month periods separated by a 2-week wash-out period in between. The objective and subjective efficiency and upper airway parameters associated with the oral appliances were assessed. One-way analysis of variance (anova) test was performed to compare the changes in upper airway morphology and the treatment efficiency between the appliances. The monoblock and SILENT NITE(®) (GlideWell Laboratories) appliances reduced Apnoea Hypopnoea Index (AHI) from 26·38 ± 4·13 to 7·58 ± 2·28 (P < 0·001) and 8·87 ± 2·88 (P < 0·001), respectively. The monoblock appliance was statistically more efficient in reducing AHI and Apnoea Index (AI) than the SILENT NITE(®) (GlideWell Laboratories) (P < 0·05). The scores on Epworth's Sleepiness Scale (ESS) and Snoring Scale (SS) were improved significantly by both appliances. The upper airway spaces showed considerable enlargement by both mandibular advancement appliances (MAAs) (P < 0·05), while no significant differences were found between the two appliances (P > 0·05). Both MAAs showed good efficacy in the treatment for mild to moderate OSAHS. Use of the monoblock appliance should be considered when patients with OSAHS choose MAA treatment, as it was more efficient in reducing the AHI and AI compared to the two-piece appliance and was preferred by most patients. Long-term efficiency should be evaluated in future prospective studies. © 2012 Blackwell Publishing Ltd.

Methotrexate-loaded PLGA nanobubbles for ultrasound imaging and Synergistic Targeted therapy of residual tumor during HIFU ablation.

PubMed

Zhang, Xuemei; Zheng, Yuanyi; Wang, Zhigang; Huang, Shuai; Chen, Yu; Jiang, Wei; Zhang, Hua; Ding, Mingxia; Li, Qingshu; Xiao, Xiaoqiu; Luo, Xin; Wang, Zhibiao; Qi, Hongbo

2014-06-01

High intensity focused ultrasound (HIFU) has attracted the great attention in tumor ablation due to its non-invasive, efficient and economic features. However, HIFU ablation has its intrinsic limitations for removing the residual tumor cells, thus the tumor recurrence and metastasis cannot be avoided in this case. Herein, we developed a multifunctional targeted poly(lactic-co-glycolic acid) (PLGA) nanobubbles (NBs), which not only function as an efficient ultrasound contrast agent for tumor imaging, but also a targeted anticancer drug carrier and excellent synergistic agent for enhancing the therapeutic efficiency of HIFU ablation. Methotrexate (MTX)-loaded NBs were synthesized and filled with perfluorocarbon gas subsequently using a facile but general double emulsion evaporation method. The active tumor-targeting monoclonal anti-HLA-G antibodies (mAbHLA-G) were further conjugated onto the surface of nanobubbles. The mAbHLA-G/MTX/PLGA NBs could enhance the ultrasound imaging both in vitro and in vivo, and the targeting efficiency to HLA-G overexpressing JEG-3 cells has been demonstrated. The elaborately designed mAbHLA-G/MTX/PLGA NBs can specifically target to the tumor cells both in vitro and in vivo, and their blood circulation time in vivo was much longer than non-targeted MTX/PLGA NBs. Further therapeutic evaluations showed that the targeted NBs as a synergistic agent can significantly improve the efficiency of HIFU ablation by changing the acoustic environment, and the focused ultrasound can promote the on-demand MTX release both in vitro and in vivo. The in vivo histopathology test and immunohistochemical analysis showed that the mAbHLA-G/MTX/PLGA NBs plus HIFU group presented most serious coagulative necrosis, the lowest proliferation index and the highest apoptotic index. Therefore, the successful introduction of targeted mAbHLA-G/MTX/PLGA NBs provides an excellent platform for the highly efficient, imaging-guided and non-invasive HIFU synergistic therapy of cancer with the supplementary functions of killing residual tumor cells and preventing tumor recurrence/metastasis. Copyright © 2014 Elsevier Ltd. All rights reserved.

Designing basin-customized combined drought indices via feature extraction

NASA Astrophysics Data System (ADS)

Zaniolo, Marta; Giuliani, Matteo; Castelletti, Andrea

2017-04-01

The socio-economic costs of drought are progressively increasing worldwide due to the undergoing alteration of hydro-meteorological regimes induced by climate change. Although drought management is largely studied in the literature, most of the traditional drought indexes fail in detecting critical events in highly regulated systems, which generally rely on ad-hoc formulations and cannot be generalized to different context. In this study, we contribute a novel framework for the design of a basin-customized drought index. This index represents a surrogate of the state of the basin and is computed by combining the available information about the water available in the system to reproduce a representative target variable for the drought condition of the basin (e.g., water deficit). To select the relevant variables and how to combine them, we use an advanced feature extraction algorithm called Wrapper for Quasi Equally Informative Subset Selection (W-QEISS). The W-QEISS algorithm relies on a multi-objective evolutionary algorithm to find Pareto-efficient subsets of variables by maximizing the wrapper accuracy, minimizing the number of selected variables (cardinality) and optimizing relevance and redundancy of the subset. The accuracy objective is evaluated trough the calibration of a pre-defined model (i.e., an extreme learning machine) of the water deficit for each candidate subset of variables, with the index selected from the resulting solutions identifying a suitable compromise between accuracy, cardinality, relevance, and redundancy. The proposed methodology is tested in the case study of Lake Como in northern Italy, a regulated lake mainly operated for irrigation supply to four downstream agricultural districts. In the absence of an institutional drought monitoring system, we constructed the combined index using all the hydrological variables from the existing monitoring system as well as the most common drought indicators at multiple time aggregations. The soil moisture deficit in the root zone computed by a distributed-parameter water balance model of the agricultural districts is used as target variable. Numerical results show that our framework succeeds in constructing a combined drought index that reproduces the soil moisture deficit. Moreover, this index represents a valuable information for supporting appropriate drought management strategies, including the possibility of directly informing the lake operations about the drought conditions and improve the overall reliability of the irrigation supply system.

Geometrical shape design of nanophotonic surfaces for thin film solar cells.

PubMed

Nam, W I; Yoo, Y J; Song, Y M

2016-07-11

We present the effect of geometrical parameters, particularly shape, on optical absorption enhancement for thin film solar cells based on crystalline silicon (c-Si) and gallium arsenide (GaAs) using a rigorous coupled wave analysis (RCWA) method. It is discovered that the "sweet spot" that maximizes efficiency of solar cells exists for the design of nanophotonic surfaces. For the case of ultrathin, rod array is practical due to the effective optical resonances resulted from the optimum geometry whereas parabola array is viable for relatively thicker cells owing to the effective graded index profile. A specific value of thickness, which is the median value of other two devices tailored by rod and paraboloid, is optimized by truncated shape structure. It is therefore worth scanning the optimum shape of nanostructures in a given thickness in order to achieve high performance.

Standardizing the evaluation of scientific and academic performance in neurosurgery--critical review of the "h" index and its variants.

PubMed

Aoun, Salah G; Bendok, Bernard R; Rahme, Rudy J; Dacey, Ralph G; Batjer, H Hunt

2013-11-01

Assessing the academic impact and output of scientists and physicians is essential to the academic promotion process and has largely depended on peer review. The inherent subjectivity of peer review, however, has led to an interest to incorporate objective measures into more established methods of academic assessment and promotion. Journal impact factor has been used to add objectivity to the process but this index alone does not capture all aspects of academic impact and achievement. The "h" index and its variants have been designed to compensate for these shortcomings, and have been successfully used in the fields of physics, mathematics, and biology, and more recently in medicine. Leaders in academic neurosurgery should be aware of the advantages offered by each of these indices, as well as of their individual shortcomings, to be able to efficiently use them to refine the peer-review process. This review critically analyzes indices that are currently available to evaluate the academic impact of scientists and physicians. These indices include the total citation count, the total number of papers, the impact factor, as well as the "h" index with eight of its most common variants. The analysis focuses on their use in the field of academic neurosurgery, and discusses means to implement them in current review processes. Copyright © 2013 Elsevier Inc. All rights reserved.

White polymeric light-emitting diodes with high color rendering index

NASA Astrophysics Data System (ADS)

Niu, Xiaodi; Ma, Liang; Yao, Bing; Ding, Junqiao; Tu, Guoli; Xie, Zhiyuan; Wang, Lixiang

2006-11-01

The efficient white polymeric light-emitting diodes based on a white emissive polymer doped with a red phosphorescent dopant were fabricated by spin-coating method. The emission spectrum of the device is broadened to cover the full visible region by doping the red phosphorescent dye and thereby realizes white emission with high color-rendering index (CRI). By controlling the contents of the doped electron-transporting 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole and the red phosphorescent dopant, a luminous efficiency as high as 5.3cd/A and a power efficiency of 3lm/W were obtained with a CRI of 92.

Second-harmonic generation at angular incidence in a negative-positive index photonic band-gap structure.

PubMed

D'Aguanno, Giuseppe; Mattiucci, Nadia; Scalora, Michael; Bloemer, Mark J

2006-08-01

In the spectral region where the refractive index of the negative index material is approximately zero, at oblique incidence, the linear transmission of a finite structure composed of alternating layers of negative and positive index materials manifests the formation of a new type of band gap with exceptionally narrow band-edge resonances. In particular, for TM-polarized (transverse magnetic) incident waves, field values that can be achieved at the band edge may be much higher compared to field values achievable in standard photonic band-gap structures. We exploit the unique properties of these band-edge resonances for applications to nonlinear frequency conversion, second-harmonic generation, in particular. The simultaneous availability of high field localization and phase matching conditions may be exploited to achieve second-harmonic conversion efficiencies far better than those achievable in conventional photonic band-gap structures. Moreover, we study the role played by absorption within the negative index material, and find that the process remains efficient even for relatively high values of the absorption coefficient.

SEMIPARAMETRIC QUANTILE REGRESSION WITH HIGH-DIMENSIONAL COVARIATES

PubMed Central

Zhu, Liping; Huang, Mian; Li, Runze

2012-01-01

This paper is concerned with quantile regression for a semiparametric regression model, in which both the conditional mean and conditional variance function of the response given the covariates admit a single-index structure. This semiparametric regression model enables us to reduce the dimension of the covariates and simultaneously retains the flexibility of nonparametric regression. Under mild conditions, we show that the simple linear quantile regression offers a consistent estimate of the index parameter vector. This is a surprising and interesting result because the single-index model is possibly misspecified under the linear quantile regression. With a root-n consistent estimate of the index vector, one may employ a local polynomial regression technique to estimate the conditional quantile function. This procedure is computationally efficient, which is very appealing in high-dimensional data analysis. We show that the resulting estimator of the quantile function performs asymptotically as efficiently as if the true value of the index vector were known. The methodologies are demonstrated through comprehensive simulation studies and an application to a real dataset. PMID:24501536

Development of noSQL data storage for the ATLAS PanDA Monitoring System

NASA Astrophysics Data System (ADS)

Ito, H.; Potekhin, M.; Wenaus, T.

2012-12-01

For several years the PanDA Workload Management System has been the basis for distributed production and analysis for the ATLAS experiment at the LHC. Since the start of data taking PanDA usage has ramped up steadily, typically exceeding 500k completed jobs/day by June 2011. The associated monitoring data volume has been rising as well, to levels that present a new set of challenges in the areas of database scalability and monitoring system performance and efficiency. These challenges are being met with an R&D effort aimed at implementing a scalable and efficient monitoring data storage based on a noSQL solution (Cassandra). We present our motivations for using this technology, as well as data design and the techniques used for efficient indexing of the data. We also discuss the hardware requirements as they were determined by testing with actual data and realistic rate of queries. In conclusion, we present our experience with operating a Cassandra cluster over an extended period of time and with data load adequate for planned application.

Evaluation of the efficiency of denture cleaners for removing denture adhesives.

PubMed

Harada-Hada, Kae; Hong, Guang; Abekura, Hitoshi; Murata, Hiroshi

2016-12-01

We developed a new scoring index for assessing the removability of denture adhesives and evaluated the removal efficiency of denture cleaners. Although our understanding of the importance of denture care is increasing, little is known about the effectiveness and efficiency of denture cleaners on denture adhesives. Therefore, guidelines for proper cleaning are necessary. We used five denture cleaner solutions on two cream adhesives, one powder adhesive and one cushion adhesive. After immersion in the denture cleaners for a designated time, we evaluated the area of the sample plate still covered by denture adhesive. Cream adhesives were removed more completely after immersion in majority of the denture cleaners than in water. Powder adhesive was removed more quickly than cream adhesives. Cushion adhesive was not removed by immersion in either the denture cleaners or water control. Some denture cleaners could liquefy cream adhesives more than water, but these differences were not observed in case of powder and cushion adhesives. © 2015 John Wiley & Sons A/S and The Gerodontology Association. Published by John Wiley & Sons Ltd.

Characterization and modeling of microstructured chalcogenide fibers for efficient mid-infrared wavelength conversion.

PubMed

Xing, Sida; Grassani, Davide; Kharitonov, Svyatoslav; Billat, Adrien; Brès, Camille-Sophie

2016-05-02

We experimentally demonstrate wavelength conversion in the 2 µm region by four-wave mixing in an AsSe and a GeAsSe chalcogenide photonic crystal fibers. A maximum conversion efficiency of -25.4 dB is measured for 112 mW of coupled continuous wave pump in a 27 cm long fiber. We estimate the dispersion parameters and the nonlinear refractive indexes of the chalcogenide PCFs, establishing a good agreement with the values expected from simulations. The different fiber geometries and glass compositions are compared in terms of performance, showing that GeAsSe is a more suited candidate for nonlinear optics at 2 µm. Building from the fitted parameters we then propose a new tapered GeAsSe PCF geometry to tailor the waveguide dispersion and lower the zero dispersion wavelength (ZDW) closer to the 2 µm pump wavelength. Numerical simulations shows that the new design allows both an increased conversion efficiency and bandwidth, and the generation of idler waves further in the mid-IR regions, by tuning the pump wavelength in the vicinity of the fiber ZDW.

Reliability Sensitivity Analysis and Design Optimization of Composite Structures Based on Response Surface Methodology

NASA Technical Reports Server (NTRS)

Rais-Rohani, Masoud

2003-01-01

This report discusses the development and application of two alternative strategies in the form of global and sequential local response surface (RS) techniques for the solution of reliability-based optimization (RBO) problems. The problem of a thin-walled composite circular cylinder under axial buckling instability is used as a demonstrative example. In this case, the global technique uses a single second-order RS model to estimate the axial buckling load over the entire feasible design space (FDS) whereas the local technique uses multiple first-order RS models with each applied to a small subregion of FDS. Alternative methods for the calculation of unknown coefficients in each RS model are explored prior to the solution of the optimization problem. The example RBO problem is formulated as a function of 23 uncorrelated random variables that include material properties, thickness and orientation angle of each ply, cylinder diameter and length, as well as the applied load. The mean values of the 8 ply thicknesses are treated as independent design variables. While the coefficients of variation of all random variables are held fixed, the standard deviations of ply thicknesses can vary during the optimization process as a result of changes in the design variables. The structural reliability analysis is based on the first-order reliability method with reliability index treated as the design constraint. In addition to the probabilistic sensitivity analysis of reliability index, the results of the RBO problem are presented for different combinations of cylinder length and diameter and laminate ply patterns. The two strategies are found to produce similar results in terms of accuracy with the sequential local RS technique having a considerably better computational efficiency.

Development and optimization of enteric coated mucoadhesive microspheres of duloxetine hydrochloride using 32 full factorial design

PubMed Central

Setia, Anupama; Kansal, Sahil; Goyal, Naveen

2013-01-01

Background: Microspheres constitute an important part of oral drug delivery system by virtue of their small size and efficient carrier capacity. However, the success of these microspheres is limited due to their short residence time at the site of absorption. Objective: The objective of the present study was to formulate and systematically evaluate in vitro performance of enteric coated mucoadhesive microspheres of duloxetine hydrochloride (DLX), an acid labile drug. Materials and Methods: DLX microspheres were prepared by simple emulsification phase separation technique using chitosan as carrier and glutaraldehyde as a cross-linking agent. Microspheres prepared were coated with eudragit L-100 using an oil-in-oil solvent evaporation method. Eudragit L-100was used as enteric coating polymer with the aim to release the drug in small intestine The microspheres prepared were characterized by particle size, entrapment efficiency, swelling index (SI), mucoadhesion time, in vitro drug release and surface morphology. A 32 full factorial design was employed to study the effect of independent variables polymer-to-drug ratio (X1) and stirring speed (X2) on dependent variables, particle size, entrapment efficiency, SI, in vitro mucoadhesion and drug release up to 24 h (t24). Results: Microspheres formed were discrete, spherical and free flowing. The microspheres exhibited good mucoadhesive property and also showed high percentage entrapment efficiency. The microspheres were able to sustain the drug release up to 24 h. Conclusion: Thus, the prepared enteric coated mucoadhesive microspheres may prove to be a potential controlled release formulation of DLX for oral administration. PMID:24167786

An implantable seal-less centrifugal pump with integrated double-disk motor.

PubMed

Schima, H; Schmallegger, H; Huber, L; Birgmann, I; Reindl, C; Schmidt, C; Roschal, K; Wieselthaler, G; Trubel, W; Losert, U

1995-07-01

Thrombus formation and sealing problems at the shaft as well as the compact and efficient design of the driving unit have been major difficulties in the construction of a long-term implantable centrifugal pump. To eliminate the problems of the seal, motor size, and efficiency, two major steps were taken by modifying the Vienna implantable centrifugal pump. First, a special driving unit was developed, in which the permanent magnets of the motor themselves are used for coupling the force into the rotor. Second, the rotor shaft in the pumping chamber was eliminated by adopting a concept recently presented by Ohara. The rotor is supported by 3 pins, which run on a carbon disk, whose concave shape leads to stabilization. The device has the following specifications: size: 65 mm (diameter) by 35 mm (height), 101 cm3; priming volume 30 cm3, 240 g; and a 6-pole brushless double disk DC motor. The required input power of the described prototype is 15 W at 150 mm Hg, 5 L/min (overall eta = 11%), and has an in vitro index of hemolysis (IH) of 0.0046 g/100 L. The test for in vitro thrombus growth exhibited far less thrombus formation in the new design than in designs with axles. In conclusion, the design of a special driving unit and the elimination of the axle led to the construction of a small pump with very low blood traumatization.

Development and optimization of solid lipid nanoparticle formulation for ophthalmic delivery of chloramphenicol using a Box-Behnken design.

PubMed

Hao, Jifu; Fang, Xinsheng; Zhou, Yanfang; Wang, Jianzhu; Guo, Fengguang; Li, Fei; Peng, Xinsheng

2011-01-01

The purpose of the present study was to optimize a solid lipid nanoparticle (SLN) of chloramphenicol by investigating the relationship between design factors and experimental data using response surface methodology. A Box-Behnken design was constructed using solid lipid (X(1)), surfactant (X(2)), and drug/lipid ratio (X(3)) level as independent factors. SLN was successfully prepared by a modified method of melt-emulsion ultrasonication and low temperature-solidification technique using glyceryl monostearate as the solid lipid, and poloxamer 188 as the surfactant. The dependent variables were entrapment efficiency (EE), drug loading (DL), and turbidity. Properties of SLN such as the morphology, particle size, zeta potential, EE, DL, and drug release behavior were investigated, respectively. As a result, the nanoparticle designed showed nearly spherical particles with a mean particle size of 248 nm. The polydispersity index of particle size was 0.277 ± 0.058 and zeta potential was -8.74 mV. The EE (%) and DL (%) could reach up to 83.29% ± 1.23% and 10.11% ± 2.02%, respectively. In vitro release studies showed a burst release at the initial stage followed by a prolonged release of chloramphenicol from SLN up to 48 hours. The release kinetics of the optimized formulation best fitted the Peppas-Korsmeyer model. These results indicated that the chloramphenicol-loaded SLN could potentially be exploited as a delivery system with improved drug entrapment efficiency and controlled drug release.

Development and optimization of solid lipid nanoparticle formulation for ophthalmic delivery of chloramphenicol using a Box-Behnken design

PubMed Central

Hao, Jifu; Fang, Xinsheng; Zhou, Yanfang; Wang, Jianzhu; Guo, Fengguang; Li, Fei; Peng, Xinsheng

2011-01-01

The purpose of the present study was to optimize a solid lipid nanoparticle (SLN) of chloramphenicol by investigating the relationship between design factors and experimental data using response surface methodology. A Box-Behnken design was constructed using solid lipid (X1), surfactant (X2), and drug/lipid ratio (X3) level as independent factors. SLN was successfully prepared by a modified method of melt-emulsion ultrasonication and low temperature-solidification technique using glyceryl monostearate as the solid lipid, and poloxamer 188 as the surfactant. The dependent variables were entrapment efficiency (EE), drug loading (DL), and turbidity. Properties of SLN such as the morphology, particle size, zeta potential, EE, DL, and drug release behavior were investigated, respectively. As a result, the nanoparticle designed showed nearly spherical particles with a mean particle size of 248 nm. The polydispersity index of particle size was 0.277 ± 0.058 and zeta potential was −8.74 mV. The EE (%) and DL (%) could reach up to 83.29% ± 1.23% and 10.11% ± 2.02%, respectively. In vitro release studies showed a burst release at the initial stage followed by a prolonged release of chloramphenicol from SLN up to 48 hours. The release kinetics of the optimized formulation best fitted the Peppas–Korsmeyer model. These results indicated that the chloramphenicol-loaded SLN could potentially be exploited as a delivery system with improved drug entrapment efficiency and controlled drug release. PMID:21556343

Effects of dietary fracture toughness and dental wear on chewing efficiency in geladas (Theropithecus gelada).

PubMed

Venkataraman, Vivek V; Glowacka, Halszka; Fritz, Julia; Clauss, Marcus; Seyoum, Chalachew; Nguyen, Nga; Fashing, Peter J

2014-09-01

Chewing efficiency has been associated with fitness in mammals, yet little is known about the behavioral, ecological, and morphological factors that influence chewing efficiency in wild animals. Although research has established that dental wear and food material properties independently affect chewing efficiency, few studies have addressed the interaction among these factors. We examined chewing efficiency, measured as mean fecal particle size, as a function of seasonal shifts in diet (and corresponding changes in food fracture toughness) in a single breeding population of a grazing primate, the gelada monkey, at Guassa, Ethiopia. We also measured dental topographic traits (slope, angularity, and relief index) and relative two- and three-dimensional shearing crest lengths in a cross-sectional wear series of gelada molars. Chewing efficiency decreased during the dry season, a pattern corresponding to the consumption of foods with higher fracture toughness. Older individuals experienced the most pronounced decreases in chewing efficiency between seasons, implicating dental wear as a causal factor. This pattern is consistent with our finding that dental topographic metrics and three-dimensional relative shearing crest lengths were lowest at the last stage of wear. Integrating these lines of behavioral, ecological, and morphological evidence provides some of the first empirical support for the hypothesis that food fracture toughness and dental wear together contribute to chewing efficiency. Geladas have the highest chewing efficiencies measured thus far in primates, and may be analogous to equids in their emphasis on dental design as a means of particle size reduction in the absence of highly specialized digestive physiology. Copyright © 2014 Wiley Periodicals, Inc.

Enhancement of white light OLED efficiency by combining both internal and external light extraction structures

NASA Astrophysics Data System (ADS)

Kao, I.-Ling; Ku, Chun-Neng; Chen, Yi-Ping; Lin, Ding-Zheng

2012-09-01

We proposed an internal nanostructure with a high reflective index planarization layer to solve the optical loss due to the reflective index mismatch between ITO and glass substrate. In our experiments, we found the electrical property of OLED device was significantly influenced by the internal nanostructures without planarization layer. Moreover, the internal extraction structure (IES) is not necessarily beneficial for light extraction. Therefore, we proposed a new substrate combine both internal and external extraction structure (EES) to extract trapping light. We successfully developed a high refractive index (N 1.7) planarization material with flat surface (RMS roughness < 2 nm), and improved about 70% device efficiency compared to traditional glass substrate.

Increasing market efficiency in the stock markets

NASA Astrophysics Data System (ADS)

Yang, Jae-Suk; Kwak, Wooseop; Kaizoji, Taisei; Kim, In-Mook

2008-01-01

We study the temporal evolutions of three stock markets; Standard and Poor's 500 index, Nikkei 225 Stock Average, and the Korea Composite Stock Price Index. We observe that the probability density function of the log-return has a fat tail but the tail index has been increasing continuously in recent years. We have also found that the variance of the autocorrelation function, the scaling exponent of the standard deviation, and the statistical complexity decrease, but that the entropy density increases as time goes over time. We introduce a modified microscopic spin model and simulate the model to confirm such increasing and decreasing tendencies in statistical quantities. These findings indicate that these three stock markets are becoming more efficient.

Kilowatt-level direct-'refractive index matching liquid'-cooled Nd:YLF thin disk laser resonator.

PubMed

Ye, Zhibin; Liu, Chong; Tu, Bo; Wang, Ke; Gao, Qingsong; Tang, Chun; Cai, Zhen

2016-01-25

A direct-liquid-cooled Nd:YLF thin disk laser resonator is presented, which features the use of refractive index matching liquid (RIML) as coolant. Highly uniform pump intensity distribution with rectangular shape is realized by using metallic planar waveguides. Much attention has been paid on the design of the gain module, including how to achieve excellent cooling ability with multi-channel coolers and how to choose the doping levels of the crystals for realizing well-distributed pump absorption. The flow velocity of the coolant is found to be a key parameter for laser performance and optimized to keep it in laminar flow status for dissipating unwanted heat load. A single channel device is used to measure the convective heat transfer coefficient (CHTC) at different flow velocities. Accordingly, the thermal stress in the disk is analyzed numerically and the maximum permissible thermal load is estimated. Experimentally, with ten pieces of a-cut Nd:YLF thin disks of different doping levels, a linear polarized laser with an average output power of 1120 W is achieved at the pump power of 5202 W, corresponding to an optical-optical efficiency of 21.5%, and a slope efficiency of 30.8%. Furthermore, the wavefront aberration of the gain module is measured to be quite weak, with a peak to valley (PV) value of 4.0 μm when it is pumped at 5202 W, which enables the feasibility of its application in an unstable resonator. To the best of our knowledge, this is the first demonstration of kilowatt-level direct-'refractive index matching liquid'-cooled Nd:YLF thin disk laser resonator.

Control Centrality and Hierarchical Structure in Complex Networks

PubMed Central

Liu, Yang-Yu; Slotine, Jean-Jacques; Barabási, Albert-László

2012-01-01

We introduce the concept of control centrality to quantify the ability of a single node to control a directed weighted network. We calculate the distribution of control centrality for several real networks and find that it is mainly determined by the network’s degree distribution. We show that in a directed network without loops the control centrality of a node is uniquely determined by its layer index or topological position in the underlying hierarchical structure of the network. Inspired by the deep relation between control centrality and hierarchical structure in a general directed network, we design an efficient attack strategy against the controllability of malicious networks. PMID:23028542

Laser-ablative engineering of phase singularities in plasmonic metamaterial arrays for biosensing applications

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

Aristov, Andrey I.; Kabashin, Andrei V., E-mail: kabashin@lp3.univ-mrs.fr; Zywietz, Urs

2014-02-17

By using methods of laser-induced transfer combined with nanoparticle lithography, we design and fabricate large-area gold nanoparticle-based metamaterial arrays exhibiting extreme Heaviside-like phase jumps in reflected light due to a strong diffractive coupling of localized plasmons. When employed in sensing schemes, these phase singularities provide the sensitivity of 5 × 10{sup 4} deg. of phase shift per refractive index unit change that is comparable with best values reported for plasmonic biosensors. The implementation of sensor platforms on the basis of such metamaterial arrays promises a drastic improvement of sensitivity and cost efficiency of plasmonic biosensing devices.

Traditional and emerging materials for optical metasurfaces

NASA Astrophysics Data System (ADS)

Zhu, Alexander Y.; Kuznetsov, Arseniy I.; Luk'yanchuk, Boris; Engheta, Nader; Genevet, Patrice

2017-03-01

One of the most promising and vibrant research areas in nanotechnology has been the field of metasurfaces. These are two dimensional representations of metaatoms, or artificial interfaces designed to possess specialized electromagnetic properties which do not occur in nature, for specific applications. In this article, we present a brief review of metasurfaces from a materials perspective, and examine how the choice of different materials impact functionalities ranging from operating bandwidth to efficiencies. We place particular emphasis on emerging and non-traditional materials for metasurfaces such as high index dielectrics, topological insulators and digital metamaterials, and the potentially transformative role they could play in shaping further advances in the field.

Taheri-Saramad x-ray detector (TSXD): a novel high spatial resolution x-ray imager based on ZnO nano scintillator wires in polycarbonate membrane.

PubMed

Taheri, A; Saramad, S; Ghalenoei, S; Setayeshi, S

2014-01-01

A novel x-ray imager based on ZnO nanowires is designed and fabricated. The proposed architecture is based on scintillation properties of ZnO nanostructures in a polycarbonate track-etched membrane. Because of higher refractive index of ZnO nanowire compared to the membrane, the nanowire acts as an optical fiber that prevents the generated optical photons to spread inside the detector. This effect improves the spatial resolution of the imager. The detection quantum efficiency and spatial resolution of the fabricated imager are 11% and <6.8 μm, respectively.

A surface impedance-based three-channel acoustic metasurface retroreflector

NASA Astrophysics Data System (ADS)

Shen, Chen; Díaz-Rubio, Ana; Li, Junfei; Cummer, Steven A.

2018-04-01

We propose the design and measurement of an acoustic metasurface retroreflector that works at three discrete incident angles. An impedance model is developed such that for acoustic waves impinging at -60°, the reflected wave is defined by the surface impedance of the metasurface, which is realized by a periodic grating. At 0° and 60°, the retroreflection condition can be fulfilled by the diffraction of the surface. The thickness of the metasurface is about half of the operating wavelength and the retroreflector functions without parasitic diffraction associated with conventional gradient-index metasurfaces. Such highly efficient and compact retroreflectors open up possibilities in metamaterial-based acoustic sensing and communications.

Subgroup identification of early preterm birth (ePTB): informing a future prospective enrichment clinical trial design.

PubMed

Zhang, Chuanwu; Garrard, Lili; Keighley, John; Carlson, Susan; Gajewski, Byron

2017-01-10

Despite the widely recognized association between the severity of early preterm birth (ePTB) and its related severe diseases, little is known about the potential risk factors of ePTB and the sub-population with high risk of ePTB. Moreover, motivated by a future confirmatory clinical trial to identify whether supplementing pregnant women with docosahexaenoic acid (DHA) has a different effect on the risk subgroup population or not in terms of ePTB prevalence, this study aims to identify potential risk subgroups and risk factors for ePTB, defined as babies born less than 34 weeks of gestation. The analysis data (N = 3,994,872) were obtained from CDC and NCHS' 2014 Natality public data file. The sample was split into independent training and validation cohorts for model generation and model assessment, respectively. Logistic regression and CART models were used to examine potential ePTB risk predictors and their interactions, including mothers' age, nativity, race, Hispanic origin, marital status, education, pre-pregnancy smoking status, pre-pregnancy BMI, pre-pregnancy diabetes status, pre-pregnancy hypertension status, previous preterm birth status, infertility treatment usage status, fertility enhancing drug usage status, and delivery payment source. Both logistic regression models with either 14 or 10 ePTB risk factors produced the same C-index (0.646) based on the training cohort. The C-index of the logistic regression model based on 10 predictors was 0.645 for the validation cohort. Both C-indexes indicated a good discrimination and acceptable model fit. The CART model identified preterm birth history and race as the most important risk factors, and revealed that the subgroup with a preterm birth history and a race designation as Black had the highest risk for ePTB. The c-index and misclassification rate were 0.579 and 0.034 for the training cohort, and 0.578 and 0.034 for the validation cohort, respectively. This study revealed 14 maternal characteristic variables that reliably identified risk for ePTB through either logistic regression model and/or a CART model. Moreover, both models efficiently identify risk subgroups for further enrichment clinical trial design.

Liquid-crystal-based tunable plasmonic waveguide filters

NASA Astrophysics Data System (ADS)

Yin, Shengtao; Liu, Yan Jun; Xiao, Dong; He, Huilin; Luo, Dan; Jiang, Shouzhen; Dai, Haitao; Ji, Wei; Sun, Xiao Wei

2018-06-01

We propose a liquid-crystal-based tunable plasmonic waveguide filter and numerically investigate its filtering properties. The filter consists of a metal-insulator-metal waveguide with a nanocavity resonator. By filling the nanocavity with birefringent liquid crystals (LCs), we could then vary the effective refractive index of the nanocavity by controlling the alignment of the LC molecules, hence making the filter tunable. The tunable filtering properties are further analyzed in details via the temporal coupled mode theory (CMT) and the finite-difference time-domain (FDTD) method. The simulation results show that the resonant wavelengths have linear redshift as the refractive index of the nanocavity increases and the coupling efficiency is more than 65% without considering the internal loss in the nanocavity and waveguides. These achieved results by the FDTD simulations can be also accurately analyzed by CMT. The compact design of our proposed plasmonic filters is especially favorable for integration, and such filters could find many important potential applications in high-density plasmonic integration circuits.

Assessment of transport performance index for urban transport development strategies — Incorporating residents' preferences

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

Ambarwati, Lasmini, E-mail: L.Ambarwati@tudelft.nl; Department of Civil Engineering, Brawijaya University; Verhaeghe, Robert, E-mail: R.Verhaeghe@tudelft.nl

The performance of urban transport depends on a variety of factors related to metropolitan structure; in particular, the patterns of commuting, roads and public transport (PT) systems. To evaluate urban transport planning efforts, there is a need for a metric expressing the aggregate performance of the city's transport systems which should relate to residents' preferences. The existing metrics have typically focused on a measure to express the proximity of job locations to residences. A Transport Performance Index (TPI) is proposed in which the total cost of transportation system (operational and environmental costs) is divided by willingness to pay (WTP) formore » transport plus the willingness to accept (WTA) the environmental effects on residents. Transport operational as well as the environmental costs are derived from a simulation of all transport systems, to particular designs of spatial development. Willingness to pay for transport and willingness to accept the environmental effects are derived from surveys among residents. Simulations were modelled of Surabaya's spatial structure and public transport expansion. The results indicate that the current TPI is high, which will double by 2030. With a hypothetical polycentric city structure and adjusted job housing balance, a lower index occurs because of the improvements in urban transport performance. A low index means that the residents obtain much benefit from the alternative proposed. This illustrates the importance of residents' preferences in urban spatial planning in order to achieve efficient urban transport. Applying the index suggests that city authorities should provide fair and equitable public transport systems for suburban residents in the effort to control the phenomenon of urban sprawl. This index is certainly a good tool and prospective benchmark for measuring sustainability in relation to urban development.« less

Scattering angle resolved optical coherence tomography for in vivo murine retinal imaging

NASA Astrophysics Data System (ADS)

Gardner, Michael R.; Katta, Nitesh; McElroy, Austin; Baruah, Vikram; Rylander, H. G.; Milner, Thomas E.

2017-02-01

Optical coherence tomography (OCT) retinal imaging contributes to understanding central nervous system (CNS) diseases because the eye is an anatomical "window to the brain" with direct optical access to nonmylenated retinal ganglion cells. However, many CNS diseases are associated with neuronal changes beyond the resolution of standard OCT retinal imaging systems. Though studies have shown the utility of scattering angle resolved (SAR) OCT for particle sizing and detecting disease states ex vivo, a compact SAR-OCT system for in vivo rodent retinal imaging has not previously been reported. We report a fiber-based SAR-OCT system (swept source at 1310 nm +/- 65 nm, 100 kHz scan rate) for mouse retinal imaging with a partial glass window (center aperture) for angular discrimination of backscattered light. This design incorporates a dual-axis MEMS mirror conjugate to the ocular pupil plane and a high collection efficiency objective. A muring retina is imaged during euthanasia, and the proposed SAR-index is examined versus time. Results show a positive correlation between the SAR-index and the sub-cellular hypoxic response of neurons to isoflurane overdose during euthanasia. The proposed SAR-OCT design and image process technique offer a contrast mechanism able to detect sub-resolution neuronal changes for murine retinal imaging.

Single mode low-NA step index Yb-doped fiber design for output powers beyond 4kW (Conference Presentation)

NASA Astrophysics Data System (ADS)

Beier, Franz; Proske, Fritz; Hupel, Christian; Kuhn, Stefan; Hein, Sigrun; Sattler, Bettina; Nold, Johannes; Haarlammert, Nicoletta; Schreiber, Thomas; Eberhardt, Ramona; Tünnermann, Andreas

2017-03-01

Fiber amplifiers are representing one of the most promising solid state laser concepts, due to the compact setup size, a simple thermal management and furthermore excellent beam quality. In this contribution, we report on the latest results from a low-NA, large mode area single mode fiber with a single mode output power beyond 4 kW without any indication of mode instabilities or nonlinear effects and high slope efficiency. Furthermore, we quantify the influence of the bending diameter of our manufactured low NA fiber on the average core loss by an OFDR measurement and determine the optimal bending diameter in comparison to a second fiber with a slightly changed NA. The fibers used in the experiments were fabricated by MCVD technology combined with the solution doping technique. The investigation indicates the limitation of the step index fiber design and its influence on the use in high power fiber amplifiers. We demonstrate, that even a slightly change in the core NA crucially influences the minimum bending diameter of the fiber and has to be taken into account in applications. The measured output power represents to the best of our knowledge the highest single mode output power of an amplifier fiber ever reported on.

Validation of Sleep-Tracking Technology Compared with Polysomnography in Adolescents

PubMed Central

de Zambotti, Massimiliano; Baker, Fiona C.; Colrain, Ian M.

2015-01-01

Study Objectives: To evaluate the accuracy in measuring nighttime sleep of a fitness tracker (Jawbone UP) compared to polysomnography (PSG). Design: Jawbone UP and PSG data were simultaneously collected from adolescents during an overnight laboratory recording. Agreements between Jawbone UP and PSG sleep outcomes were analyzed using paired t tests and Bland-Altman plots. Multiple regressions were used to investigate which PSG sleep measures predicted Jawbone UP “Sound sleep” and “Light sleep.” Setting: SRI International Human Sleep Laboratory. Participants: Sixty-five healthy adolescents (28 females, mean age ± standard deviation [SD]: 15.8 ± 2.5 y). Interventions: N/A. Measurements and Results: Outcomes showed good agreements between Jawbone UP and PSG for total sleep time (mean differences ± SD: −10.0 ± 20.5 min), sleep efficiency (mean differences ± SD: −1.9 ± 4.2 %), and wake after sleep onset (WASO) (mean differences ± SD: 10.6 ± 14.7 min). Overall, Jawbone UP overestimated PSG total sleep time and sleep efficiency and underestimated WASO but differences were small and, on average, did not exceed clinically meaningful cutoffs of > 30 min for total sleep time and > 5% for sleep efficiency. Multiple regression models showed that Jawbone UP “Sound sleep” measure was predicted by PSG time in N2 (β = 0.25), time in rapid eye movement (β = 0.29), and arousal index (β = −0.34). Jawbone UP “Light sleep” measure was predicted by PSG time in N2 (β = 0.48), time in N3 (β = 0.49), arousal index (β = 0.38) and awakening index (β = 0.28). Jawbone UP showed a progression from slight overestimation to underestimation of total sleep time and sleep efficiency with advancing age. All relationships were similar in boys and girls. Conclusions: Jawbone UP shows good agreement with polysomnography in measures of total sleep time and wake after sleep onset in adolescent boys and girls. Further validation is needed in other age groups and clinical populations before advocating use of these inexpensive and easy-to-use devices in clinical sleep medicine and research. Citation: de Zambotti M, Baker FC, Colrain IM. Validation of sleep-tracking technology compared with polysomnography in adolescents. SLEEP 2015;38(9):1461–1468. PMID:26158896

Associations of Self-Reported and Actigraphy-Assessed Sleep Characteristics with Body Mass Index and Waist Circumference in Adults: Moderation by Gender

PubMed Central

Mezick, Elizabeth J.; Wing, Rena R.; McCaffery, Jeanne M.

2013-01-01

Objectives Self-reported sleep duration has been linked to body mass index (BMI) and waist circumference in previous work; however, data regarding whether these associations are stronger in men or women have been mixed, and few studies have measured sleep objectively. We investigated self-reported and actigraphy-assessed sleep characteristics in relation to BMI and waist circumference, and examined the extent to which these associations differ by gender. Design Archived, cross-sectional data from the National Survey of Midlife Development in the United States (MIDUS) Biomarkers Study, collected in 2004–2006, were used. Participants included 1248 adults (43% male) who reported their habitual sleep duration, and a subset of participants (n = 441, 40% male) who underwent seven nights of wrist actigraphy. Results Self-reported total sleep time, actigraphy-assessed total sleep time, and actigraphy-assessed sleep efficiency were inversely associated with BMI in the full sample of both men and women. Gender moderated associations between actigraphy assessments of sleep and anthropometric variables, however, such that total sleep time and sleep efficiency were related to BMI and waist circumference in women only. Associations between sleep and waist circumference were independent of BMI. Conclusions Sleep duration and sleep continuity are associated with body weight and distribution of body fat, but these associations are stronger, or only present, in women. PMID:24239499

Parallel screening of drug-like natural compounds using Caco-2 cell permeability QSAR model with applicability domain, lipophilic ligand efficiency index and shape property: A case study of HIV-1 reverse transcriptase inhibitors

NASA Astrophysics Data System (ADS)

Patel, Rikin D.; Kumar, Sivakumar Prasanth; Patel, Chirag N.; Shankar, Shetty Shilpa; Pandya, Himanshu A.; Solanki, Hitesh A.

2017-10-01

The traditional drug design strategy centrally focuses on optimizing binding affinity with the receptor target and evaluates pharmacokinetic properties at a later stage which causes high rate of attrition in clinical trials. Alternatively, parallel screening allows evaluation of these properties and affinity simultaneously. In a case study to identify leads from natural compounds with experimental HIV-1 reverse transcriptase (RT) inhibition, we integrated various computational approaches including Caco-2 cell permeability QSAR model with applicability domain (AD) to recognize drug-like natural compounds, molecular docking to study HIV-1 RT interactions and shape similarity analysis with known crystal inhibitors having characteristic butterfly-like model. Further, the lipophilic properties of the compounds refined from the process with best scores were examined using lipophilic ligand efficiency (LLE) index. Seven natural compound hits viz. baicalien, (+)-calanolide A, mniopetal F, fagaronine chloride, 3,5,8-trihydroxy-4-quinolone methyl ether derivative, nitidine chloride and palmatine, were prioritized based on LLE score which demonstrated Caco-2 well absorption labeling, encompassment in AD structural coverage, better receptor affinity, shape adaptation and permissible AlogP value. We showed that this integrative approach is successful in lead exploration of natural compounds targeted against HIV-1 RT enzyme.

Laser performance and modeling of RE3+:YAG double-clad crystalline fiber waveguides

NASA Astrophysics Data System (ADS)

Li, Da; Lee, Huai-Chuan; Meissner, Stephanie K.; Meissner, Helmuth E.

2018-02-01

We report on laser performance of ceramic Yb:YAG and single crystal Tm:YAG double-clad crystalline fiber waveguide (CFW) lasers towards the goal of demonstrating the design and manufacturing strategy of scaling to high output power. The laser component is a double-clad CFW, with RE3+:YAG (RE = Yb, Tm respectively) core, un-doped YAG inner cladding, and ceramic spinel or sapphire outer cladding. Laser performance of the CFW has been demonstrated with 53.6% slope efficiency and 27.5-W stable output power at 1030-nm for Yb:YAG CFW, and 31.6% slope efficiency and 46.7-W stable output power at 2019-nm for Tm:YAG CFW, respectively. Adhesive-Free Bond (AFB®) technology enables a designable refractive index difference between core and inner cladding, and designable core and inner cladding sizes, which are essential for single transverse mode CFW propagation. To guide further development of CFW designs, we present thermal modeling, power scaling and design of single transverse mode operation of double-clad CFWs and redefine the single-mode operation criterion for the double-clad structure design. The power scaling modeling of double-clad CFW shows that in order to achieve the maximum possible output power limited by the physical properties, including diode brightness, thermal lens effect, and simulated Brillion scattering, the length of waveguide is in the range of 0.5 2 meters. The length of an individual CFW is limited by single crystal growth and doping uniformity to about 100 to 200 mm lengths, and also by availability of starting crystals and manufacturing complexity. To overcome the limitation of CFW lengths, end-to-end proximity-coupling of CFWs is introduced.

Enhancement and inhibition of second-harmonic generation and absorption in a negative index cavity.

PubMed

de Ceglia, Domenico; D'Orazio, Antonella; De Sario, Marco; Petruzzelli, Vincenzo; Prudenzano, Francesco; Centini, Marco; Cappeddu, Mirko G; Bloemer, Mark J; Scalora, Michael

2007-02-01

We study second-harmonic generation in a negative-index material cavity. The transmission spectrum shows a bandgap between the electric and magnetic plasma frequencies. The nonlinear process is made efficient by local phase-matching conditions between a forward-propagating pump and a backward-propagating second-harmonic signal. By simultaneously exciting the cavity with counterpropagating pulses, and by varying their relative phase difference, one is able to enhance or inhibit linear absorption and the second-harmonic conversion efficiency.

ProtocolNavigator: emulation-based software for the design, documentation and reproduction biological experiments.

PubMed

Khan, Imtiaz A; Fraser, Adam; Bray, Mark-Anthony; Smith, Paul J; White, Nick S; Carpenter, Anne E; Errington, Rachel J

2014-12-01

Experimental reproducibility is fundamental to the progress of science. Irreproducible research decreases the efficiency of basic biological research and drug discovery and impedes experimental data reuse. A major contributing factor to irreproducibility is difficulty in interpreting complex experimental methodologies and designs from written text and in assessing variations among different experiments. Current bioinformatics initiatives either are focused on computational research reproducibility (i.e. data analysis) or laboratory information management systems. Here, we present a software tool, ProtocolNavigator, which addresses the largely overlooked challenges of interpretation and assessment. It provides a biologist-friendly open-source emulation-based tool for designing, documenting and reproducing biological experiments. ProtocolNavigator was implemented in Python 2.7, using the wx module to build the graphical user interface. It is a platform-independent software and freely available from http://protocolnavigator.org/index.html under the GPL v2 license. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Design, characterization, and in vitro cellular inhibition and uptake of optimized genistein-loaded NLC for the prevention of posterior capsular opacification using response surface methodology.

PubMed

Zhang, Wenji; Li, Xuedong; Ye, Tiantian; Chen, Fen; Sun, Xiao; Kong, Jun; Yang, Xinggang; Pan, Weisan; Li, Sanming

2013-09-15

This study was to design an innovative nanostructured lipid carrier (NLC) for drug delivery of genistein applied after cataract surgery for the prevention of posterior capsular opacification. NLC loaded with genistein (GEN-NLC) was produced with Compritol 888 ATO, Gelucire 44/14 and Miglyol 812N, stabilized by Solutol(®) HS15 by melt emulsification method. A 2(4) central composite design of 4 independent variables was performed for optimization. Effects of drug concentration, Gelucire 44/14 concentration in total solid lipid, liquid lipid concentration, and surfactant concentration on the mean particle size, polydispersity index, zeta potential and encapsulation efficiency were investigated. Analysis of variance (ANOVA) statistical test was used to assess the optimization. The optimized GEN-NLC showed a homogeneous particle size of 90.16 nm (with PI=0.33) of negatively charged surface (-25.08 mv) and high encapsulation efficiency (91.14%). Particle morphology assessed by TEM revealed a spherical shape. DSC analyses confirmed that GEN was mostly entrapped in amorphous state. In vitro release experiments indicated a prolonged and controlled genistein release for 72 h. In vitro growth inhibition assay showed an effective growth inhibition of GEN-NLCs on human lens epithelial cells (HLECs). Preliminary cellular uptake test proved a enhanced penetration of genistein into HLECs when delivered in NLC. Copyright © 2013 Elsevier B.V. All rights reserved.

Safety assessment in plant layout design using indexing approach: implementing inherent safety perspective. Part 2-Domino Hazard Index and case study.

PubMed

Tugnoli, Alessandro; Khan, Faisal; Amyotte, Paul; Cozzani, Valerio

2008-12-15

The design of layout plans requires adequate assessment tools for the quantification of safety performance. The general focus of the present work is to introduce an inherent safety perspective at different points of the layout design process. In particular, index approaches for safety assessment and decision-making in the early stages of layout design are developed and discussed in this two-part contribution. Part 1 (accompanying paper) of the current work presents an integrated index approach for safety assessment of early plant layout. In the present paper (Part 2), an index for evaluation of the hazard related to the potential of domino effects is developed. The index considers the actual consequences of possible escalation scenarios and scores or ranks the subsequent accident propagation potential. The effects of inherent and passive protection measures are also assessed. The result is a rapid quantification of domino hazard potential that can provide substantial support for choices in the early stages of layout design. Additionally, a case study concerning selection among various layout options is presented and analyzed. The case study demonstrates the use and applicability of the indices developed in both parts of the current work and highlights the value of introducing inherent safety features early in layout design.

Evaluation of a Cubature Kalman Filtering-Based Phase Unwrapping Method for Differential Interferograms with High Noise in Coal Mining Areas

PubMed Central

Liu, Wanli; Bian, Zhengfu; Liu, Zhenguo; Zhang, Qiuzhao

2015-01-01

Differential interferometric synthetic aperture radar has been shown to be effective for monitoring subsidence in coal mining areas. Phase unwrapping can have a dramatic influence on the monitoring result. In this paper, a filtering-based phase unwrapping algorithm in combination with path-following is introduced to unwrap differential interferograms with high noise in mining areas. It can perform simultaneous noise filtering and phase unwrapping so that the pre-filtering steps can be omitted, thus usually retaining more details and improving the detectable deformation. For the method, the nonlinear measurement model of phase unwrapping is processed using a simplified Cubature Kalman filtering, which is an effective and efficient tool used in many nonlinear fields. Three case studies are designed to evaluate the performance of the method. In Case 1, two tests are designed to evaluate the performance of the method under different factors including the number of multi-looks and path-guiding indexes. The result demonstrates that the unwrapped results are sensitive to the number of multi-looks and that the Fisher Distance is the most suitable path-guiding index for our study. Two case studies are then designed to evaluate the feasibility of the proposed phase unwrapping method based on Cubature Kalman filtering. The results indicate that, compared with the popular Minimum Cost Flow method, the Cubature Kalman filtering-based phase unwrapping can achieve promising results without pre-filtering and is an appropriate method for coal mining areas with high noise. PMID:26153776

An efficient self-collimating photonic crystal coupling technique in the RF regime

NASA Astrophysics Data System (ADS)

Sabas, Jerico N.; Mirza, Iftekhar O.; Shi, Shouyuan; Prather, Dennis W.

2010-02-01

In this paper, we present both numerical and experimental results for the waveguiding of light using a low-index-contrast (LIC) self-collimating photonic crystal (SCPhC) in the RF frequency regime. This waveguiding structure utilizes the unique interactions of light with the periodic structure of the photonic crystal (PhC) to propagate a beam of light without divergence. This design also employs materials with a low index contrast (LIC), which reduces the electromagnetic signature of the PhC. This SCPhC was designed by extracting its dispersion contours and numerically simulating it using HFSS, a commercial 3-D, full-wave FEM software. In particular, we addressed the issue of coupling the PhC to a coaxial medium by designing an input/output (I/O) coupler consisting of a coaxial-to-waveguide transition, a rectangular waveguide and a tapered dielectric transition. We fabricated the SCPhC with a rigid polyurethane foam slab and Rexolite polystyrene rods using an automated CNC router to drill the periodic lattice in the slab. We also fabricated the dielectric segments of the I/O couplers with Rexolite slabs using an automated milling machine. Using these I/O couplers and SCPhC slab, we simulated and subsequently measured experimentally an insertion loss, for the entire system, of -3.3 dB through a 24" PhC slab, and a coupling loss of -0.95 dB at each coupler-PhC interface.

A modified multi-objective particle swarm optimization approach and its application to the design of a deepwater composite riser

NASA Astrophysics Data System (ADS)

Zheng, Y.; Chen, J.

2017-09-01

A modified multi-objective particle swarm optimization method is proposed for obtaining Pareto-optimal solutions effectively. Different from traditional multi-objective particle swarm optimization methods, Kriging meta-models and the trapezoid index are introduced and integrated with the traditional one. Kriging meta-models are built to match expensive or black-box functions. By applying Kriging meta-models, function evaluation numbers are decreased and the boundary Pareto-optimal solutions are identified rapidly. For bi-objective optimization problems, the trapezoid index is calculated as the sum of the trapezoid's area formed by the Pareto-optimal solutions and one objective axis. It can serve as a measure whether the Pareto-optimal solutions converge to the Pareto front. Illustrative examples indicate that to obtain Pareto-optimal solutions, the method proposed needs fewer function evaluations than the traditional multi-objective particle swarm optimization method and the non-dominated sorting genetic algorithm II method, and both the accuracy and the computational efficiency are improved. The proposed method is also applied to the design of a deepwater composite riser example in which the structural performances are calculated by numerical analysis. The design aim was to enhance the tension strength and minimize the cost. Under the buckling constraint, the optimal trade-off of tensile strength and material volume is obtained. The results demonstrated that the proposed method can effectively deal with multi-objective optimizations with black-box functions.

Electrochemical model based charge optimization for lithium-ion batteries

NASA Astrophysics Data System (ADS)

Pramanik, Sourav; Anwar, Sohel

2016-05-01

In this paper, we propose the design of a novel optimal strategy for charging the lithium-ion battery based on electrochemical battery model that is aimed at improved performance. A performance index that aims at minimizing the charging effort along with a minimum deviation from the rated maximum thresholds for cell temperature and charging current has been defined. The method proposed in this paper aims at achieving a faster charging rate while maintaining safe limits for various battery parameters. Safe operation of the battery is achieved by including the battery bulk temperature as a control component in the performance index which is of critical importance for electric vehicles. Another important aspect of the performance objective proposed here is the efficiency of the algorithm that would allow higher charging rates without compromising the internal electrochemical kinetics of the battery which would prevent abusive conditions, thereby improving the long term durability. A more realistic model, based on battery electro-chemistry has been used for the design of the optimal algorithm as opposed to the conventional equivalent circuit models. To solve the optimization problem, Pontryagins principle has been used which is very effective for constrained optimization problems with both state and input constraints. Simulation results show that the proposed optimal charging algorithm is capable of shortening the charging time of a lithium ion cell while maintaining the temperature constraint when compared with the standard constant current charging. The designed method also maintains the internal states within limits that can avoid abusive operating conditions.

Novel high refractive index, thermally conductive additives for high brightness white LEDs

NASA Astrophysics Data System (ADS)

Hutchison, Richard Stephen

In prior works the inclusion of nanoparticle fillers has typically been shown to increase the thermal conductivity or refractive index of polymer nanocomposites separately. High refractive index zirconia nanoparticles have already proved their merit in increasing the optical efficiency of encapsulated light emitting diodes. However, the thermal properties of zirconia-silicone nanocomposites have yet to be investigated. While phosphor-converted light emitting diodes are at the forefront of solid-state lighting technologies for producing white light, they are plagued by efficiency losses due to excessive heating at the semiconductor die and in and around the phosphor particles, as well as photon scattering losses in the phosphor layer. It would then be of great interest if the high refractive index nanoparticles were found to both be capable of increasing the refractive index, thus reducing the optical scattering, and also the thermal conductivity, channeling more heat away from the LED die and phosphors, mitigating efficiency losses from heat. Thermal conductance measurements on unfilled and nanoparticle loaded silicone samples were conducted to quantify the effect of the zirconia nanoparticle loading on silicone nanocomposite thermal conductivity. An increase in thermal conductivity from 0.27 W/mK to 0.49 W/mK from base silicone to silicone with 33.5 wt% zirconia nanoparticles was observed. This trend closely mirrored a basic rule of mixtures prediction, implying a further enhancement in thermal conductivity could be achieved at higher nanoparticle loadings. The optical properties of transparency and light extraction efficiency of these composites were also investigated. While overall the zirconia nanocomposite showed good transparency, there was a slight decrease at the shorter wavelengths with increasing zirconia content. For longer wavelength LEDs, such as green or red, this might not matter, but phosphor-converted white LEDs use a blue LED as the photon source making this decrease in transparency important to note. This decrease in transparency may be partially or wholly why a decrease in light extraction efficiency is observed at the 33.5 wt% zirconia loading fraction used for the LED samples. Preliminary aging studies under full and enhanced power conditions were conducted over 500 and 1000 hours to observe any changes in the spectral output power and phosphor conversion efficiency of the LEDs due to inclusion of the zirconia nanoparticles. It was found that the nanoparticles have no negative effect on the aging properties but also show no enhancement in relative output power over a preliminary aging study. However, their inclusion did result in increased phosphor conversion efficiency over the use of an unfilled silicone. This increase was seen as around a 10% or greater enhancement for the nanocomposite over that for the base Sylgard silicone. These experiments were originally conducted on the commercially available methylated Sylgard 184 silicone and then again on a higher refractive index methyl-phenyl silicone from Momentive. While some of the results from the Momentive silicone were perplexing, it was seen that, even without the inclusion of nanoparticles, the Momentive silicone had a higher refractive index, better aging properties, and a higher phosphor conversion efficiency over 500 hours under enhanced power conditions, warranting further studies into methyl-phenyl silicone nanocomposites.

Selected Private Higher Educational Institutions in Metro Manila: A DEA Efficiency Measurement

ERIC Educational Resources Information Center

de Guzman, Maria Corazon Gwendolyn N.; Cabana, Emilyn

2009-01-01

This paper measures the technical efficiency of 16 selected colleges and universities in Metro Manila, Philippines, using academic data for the SY 2001-2005. Using the data envelopment analysis (DEA), on average, schools posted 0.807 index score and need additional 19.3% efficiency growth to be efficient. Overall, there are top four efficient…

The Design and Development of BMI Calc Android Application

NASA Astrophysics Data System (ADS)

Mohd Ali, Iliana; Samsudin, Nooraida

2016-11-01

Body mass index is a familiar term for those who are weight conscious. It is the term that let user know about the overall body composition in terms of fat.The available body mass index calculators whether online or on Play Store do not provide Malaysian meal suggestions. Hence, this paper proposes an application for body mass index calculator together with Malaysian meal suggestion. The objectives of the study are to design and develop BMI Calc android application for the purpose of calculating body mass index while embedding meal suggestion module. The design and methodology involve in the process are also presented.

Designing a generalized soil-adjusted vegetation index (GESAVI)

NASA Astrophysics Data System (ADS)

Gilabert, M. A.; Gonzalez Piqueras, Jose; Garcia-Haro, Joan; Melia, J.

1998-12-01

Operational monitoring of vegetative cover by remote sensing currently involves the utilization of vegetation indices (VIs), most of them being functions of the reflectance in red (R) and near-infrared (NIR) spectral bands. A generalized soil-adjusted vegetation index (GESAVI), theoretically based on a simple vegetation canopy model, is introduced. It is defined in terms of the soil line parameters (A and B) as: GESAVI equals (NIR-BR-A)/(R + Z), where Z is related to the red reflectance at the cross point between the soil line and vegetation isolines. Z can be considered as a soil adjustment coefficient which let this new index be considered as belonging to the SAVI family. In order to analyze the GESAVI sensitivity to soil brightness and soil color, both high resolution reflectance data from two laboratory experiments and data obtained by applying a radiosity model to simulate heterogeneous vegetation canopy scenes were used. VIs (including GESAVI, NDVI, PVI and SAVI family VIs) were computed and their correlation with LAI for the different soil backgrounds was analyzed. Results confirmed the lower sensitivity of GESAVI to soil background in most of the cases, thus becoming the most efficient index. This good index performance results from the fact that the isolines in the NIR-R plane are neither parallel to the soil line (as required by the PVI) nor convergent at the origin (as required by the NDVI) but they converge somewhere between the origin and infinity in the region of negative values of both NIR and R. This convergence point is not necessarily situated on the bisectrix, as required by other SAVI family indices.

New model performance index for engineering design of control systems

NASA Technical Reports Server (NTRS)

1970-01-01

Performance index includes a model representing linear control-system design specifications. Based on a geometric criterion for approximation of the model by the actual system, the index can be interpreted directly in terms of the desired system response model without actually having the model's time response.

76 FR 11432 - Coding of Design Marks in Registrations

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-02

... on the old paper search designations. The USPTO will continue to code all pending applications that... system, the Trademark Search Facility Classification Code Index (``TC Index''), stems from its... infrequent use of the TC Index codes in searches by the public; and its costliness to maintain, especially in...

A secure data outsourcing scheme based on Asmuth-Bloom secret sharing

NASA Astrophysics Data System (ADS)

Idris Muhammad, Yusuf; Kaiiali, Mustafa; Habbal, Adib; Wazan, A. S.; Sani Ilyasu, Auwal

2016-11-01

Data outsourcing is an emerging paradigm for data management in which a database is provided as a service by third-party service providers. One of the major benefits of offering database as a service is to provide organisations, which are unable to purchase expensive hardware and software to host their databases, with efficient data storage accessible online at a cheap rate. Despite that, several issues of data confidentiality, integrity, availability and efficient indexing of users' queries at the server side have to be addressed in the data outsourcing paradigm. Service providers have to guarantee that their clients' data are secured against internal (insider) and external attacks. This paper briefly analyses the existing indexing schemes in data outsourcing and highlights their advantages and disadvantages. Then, this paper proposes a secure data outsourcing scheme based on Asmuth-Bloom secret sharing which tries to address the issues in data outsourcing such as data confidentiality, availability and order preservation for efficient indexing.

A Philosophical Approach to Quantum Field Theory

NASA Astrophysics Data System (ADS)

Öttinger, Hans Christian

2018-01-01

Preface; Acknowledgements; 1. Approach to quantum field theory; 2. Scalar field theory; 3. Quantum electrodynamics; 4. Perspectives; Appendix A. An efficient perturbation scheme; Appendix B. Properties of Dirac matrices; Appendix C. Baker-Campbell-Hausdorff formulas; References; Author index; Subject index.

Silicon Nitride Antireflection Coatings for Photovoltaic Cells

NASA Technical Reports Server (NTRS)

Johnson, C.; Wydeven, T.; Donohoe, K.

1984-01-01

Chemical-vapor deposition adapted to yield graded index of refraction. Silicon nitride deposited in layers, refractive index of which decreases with distance away from cell/coating interface. Changing index of refraction allows adjustment of spectral transmittance for wavelengths which cell is most effective at converting light to electric current. Average conversion efficiency of solar cells increased from 8.84 percent to 12.63 percent.

Indexing and filing of pathological illustrations.

PubMed Central

Brown, R A; Fawkes, R S; Beck, J S

1975-01-01

An inexpensive feature card retrieval system has been combined with the Systematised Nomenclature of Pathology (SNOP) to provide simple but efficient means of indexing and filing 2 in. x 2 in. transparencies within a department of pathology. Using this system 2400 transparencies and the associated index cards can be conveniently stored in one drawer of a standard filing cabinet. Images PMID:1123438

Fabrication process for a gradient index x-ray lens

DOEpatents

Bionta, R.M.; Makowiecki, D.M.; Skulina, K.M.

1995-01-17

A process is disclosed for fabricating high efficiency x-ray lenses that operate in the 0.5-4.0 keV region suitable for use in biological imaging, surface science, and x-ray lithography of integrated circuits. The gradient index x-ray optics fabrication process broadly involves co-sputtering multi-layers of film on a wire, followed by slicing and mounting on block, and then ion beam thinning to a thickness determined by periodic testing for efficiency. The process enables the fabrication of transmissive gradient index x-ray optics for the 0.5-4.0 keV energy range. This process allows the fabrication of optical elements for the next generation of imaging and x-ray lithography instruments in the soft x-ray region. 13 figures.

An Efficient G-XML Data Management Method using XML Spatial Index for Mobile Devices

NASA Astrophysics Data System (ADS)

Tamada, Takashi; Momma, Kei; Seo, Kazuo; Hijikata, Yoshinori; Nishida, Shogo

This paper presents an efficient G-XML data management method for mobile devices. G-XML is XML based encoding for the transport of geographic information. Mobile devices, such as PDA and mobile-phone, performance trail desktop machines, so some techniques are needed for processing G-XML data on mobile devices. In this method, XML-format spatial index file is used to improve an initial display time of G-XML data. This index file contains XML pointer of each feature in G-XML data and classifies these features by multi-dimensional data structures. From the experimental result, we can prove this method speed up about 3-7 times an initial display time of G-XML data on mobile devices.

Fabrication process for a gradient index x-ray lens

DOEpatents

Bionta, Richard M.; Makowiecki, Daniel M.; Skulina, Kenneth M.

1995-01-01

A process for fabricating high efficiency x-ray lenses that operate in the 0.5-4.0 keV region suitable for use in biological imaging, surface science, and x-ray lithography of integrated circuits. The gradient index x-ray optics fabrication process broadly involves co-sputtering multi-layers of film on a wire, followed by slicing and mounting on block, and then ion beam thinning to a thickness determined by periodic testing for efficiency. The process enables the fabrication of transmissive gradient index x-ray optics for the 0.5-4.0 keV energy range. This process allows the fabrication of optical elements for the next generation of imaging and x-ray lithography instruments m the soft x-ray region.

Polymeric nanoparticles loaded with the 3,5,3'-triiodothyroacetic acid (Triac), a thyroid hormone: factorial design, characterization, and release kinetics.

PubMed

Dos Santos, Karen C; da Silva, Maria Fatima Gf; Pereira-Filho, Edenir R; Fernandes, Joao B; Polikarpov, Igor; Forim, Moacir R

2012-01-01

This present investigation deals with the development and optimization of polymeric nanoparticle systems loaded with 3,5,3'-triiodothyroacetic acid (Triac). A 2(11-6) fractional factorial design and another 2(2) factorial design were used to study the contrasts on particle size distribution, morphology, surface charge, drug content, entrapment efficiency, and in vitro drug release profiles. The independent variables were the concentration of Triac, type and quantity of both polymer and oil, quantity of Span™ 60 and Tween® 80, volume of solvent and water, and velocity of both magnetic stirring and the transfer of the organic phase into the aqueous solution. The results of optimized formulations showed a narrow size distribution with a polydispersity index lower than 0.200. The particle sizes were on average 159.6 nm and 285.6 nm for nanospheres and nanocapsules, respectively. The zeta potential was higher than 20 mV (in module) and the entrapment efficiency was nearly 100%. A high-performance liquid chromatography method was developed, validated, and efficiently applied to Triac quantification in colloidal suspension. The main independent variables were the type and quantity of the polymer and oil. In vitro drug release profile depicted several features to sustain Triac release. Different formulations showed various release rates indicating an interaction between Triac and other formulation compounds such as polymer and/or oil quantity. Two different models were identified (biexponential and monoexponential) that allowed the control of both the release rate and Triac concentration. Thus, the prepared nanoparticles described here may be of clinical importance in delivering Triac for thyroid treatment.

Effectiveness and efficiency of a CAD/CAM orthodontic bracket system.

PubMed

Brown, Matthew W; Koroluk, Lorne; Ko, Ching-Chang; Zhang, Kai; Chen, Mengqi; Nguyen, Tung

2015-12-01

The first straight-wire appliance was introduced over 40 years ago to increase the consistency and efficiency of orthodontic treatment. More recently, computer-aided design and computer-aided manufacturing (CAD/CAM) technology has been used to create individualized orthodontic appliances. The purpose of this study was to investigate the clinical effectiveness and efficiency of CAD/CAM customized orthodontic appliances compared with direct and indirect bonded stock orthodontic brackets. This retrospective study included 3 treatment groups: group 1 patients were direct bonded with self-ligating appliances, group 2 patients were indirect bonded with self-ligating appliances, and group 3 patients were indirect bonded with CAD/CAM self-ligating appliances. Complete pretreatment and posttreatment records were obtained for all patients. The American Board of Orthodontics (ABO) Discrepancy Index was used to evaluate the pretreatment records, and the posttreatment outcomes were analyzed using the ABO Cast-Radiograph Evaluation. All data collection and analysis were completed by 1 evaluator. There were no statistically significant differences in the ABO Discrepancy Index or the ABO Cast-Radiograph Evaluation among the groups. Treatment times for the 3 groups were significantly different; the CAD/CAM group was the shortest at 13.8 ± 3.4 months, compared with 21.9 ± 5.0 and 16.9 ± 4.1 months for the direct bonded and indirect bonded groups, respectively. The number of treatment appointments for the CAD/CAM group was significantly fewer than for the direct bonded group. The CAD/CAM orthodontic bracket system evaluated in this study was as effective in treatment outcome measures as were standard brackets bonded both directly and indirectly. The CAD/CAM appliance was more efficient in regard to treatment duration, although the decrease in total archwire appointments was minimal. Further investigation is needed to better quantify the clinical benefits of CAD/CAM orthodontic appliances. Copyright © 2015 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

Smiles2Monomers: a link between chemical and biological structures for polymers.

PubMed

Dufresne, Yoann; Noé, Laurent; Leclère, Valérie; Pupin, Maude

2015-01-01

The monomeric composition of polymers is powerful for structure comparison and synthetic biology, among others. Many databases give access to the atomic structure of compounds but the monomeric structure of polymers is often lacking. We have designed a smart algorithm, implemented in the tool Smiles2Monomers (s2m), to infer efficiently and accurately the monomeric structure of a polymer from its chemical structure. Our strategy is divided into two steps: first, monomers are mapped on the atomic structure by an efficient subgraph-isomorphism algorithm ; second, the best tiling is computed so that non-overlapping monomers cover all the structure of the target polymer. The mapping is based on a Markovian index built by a dynamic programming algorithm. The index enables s2m to search quickly all the given monomers on a target polymer. After, a greedy algorithm combines the mapped monomers into a consistent monomeric structure. Finally, a local branch and cut algorithm refines the structure. We tested this method on two manually annotated databases of polymers and reconstructed the structures de novo with a sensitivity over 90 %. The average computation time per polymer is 2 s. s2m automatically creates de novo monomeric annotations for polymers, efficiently in terms of time computation and sensitivity. s2m allowed us to detect annotation errors in the tested databases and to easily find the accurate structures. So, s2m could be integrated into the curation process of databases of small compounds to verify the current entries and accelerate the annotation of new polymers. The full method can be downloaded or accessed via a website for peptide-like polymers at http://bioinfo.lifl.fr/norine/smiles2monomers.jsp.Graphical abstract:.

Reciprocating and Screw Compressor semi-empirical models for establishing minimum energy performance standards

NASA Astrophysics Data System (ADS)

Javed, Hassan; Armstrong, Peter

2015-08-01

The efficiency bar for a Minimum Equipment Performance Standard (MEPS) generally aims to minimize energy consumption and life cycle cost of a given chiller type and size category serving a typical load profile. Compressor type has a significant chiller performance impact. Performance of screw and reciprocating compressors is expressed in terms of pressure ratio and speed for a given refrigerant and suction density. Isentropic efficiency for a screw compressor is strongly affected by under- and over-compression (UOC) processes. The theoretical simple physical UOC model involves a compressor-specific (but sometimes unknown) volume index parameter and the real gas properties of the refrigerant used. Isentropic efficiency is estimated by the UOC model and a bi-cubic, used to account for flow, friction and electrical losses. The unknown volume index, a smoothing parameter (to flatten the UOC model peak) and bi-cubic coefficients are identified by curve fitting to minimize an appropriate residual norm. Chiller performance maps are produced for each compressor type by selecting optimized sub-cooling and condenser fan speed options in a generic component-based chiller model. SEER is the sum of hourly load (from a typical building in the climate of interest) and specific power for the same hourly conditions. An empirical UAE cooling load model, scalable to any equipment capacity, is used to establish proposed UAE MEPS. Annual electricity use and cost, determined from SEER and annual cooling load, and chiller component cost data are used to find optimal chiller designs and perform life-cycle cost comparison between screw and reciprocating compressor-based chillers. This process may be applied to any climate/load model in order to establish optimized MEPS for any country and/or region.

Influence of body mass index on movement efficiency among firefighter recruits.

PubMed

Cornell, David J; Gnacinski, Stacy L; Zamzow, Aaron; Mims, Jason; Ebersole, Kyle T

2016-06-04

Previous research has demonstrated links between musculoskeletal injury risk and measures of obesity and movement efficiency among the firefighter population. However, the influence of obesity on movement efficiency among firefighter recruits remains uninvestigated. To investigate the influence of obesity on movement efficiency measures among firefighter recruits. Measures of obesity were collected among 73 male firefighter recruits. Participants were grouped into standard body mass index (BMI) categories (normal, overweight, obese). Differences in Total Functional Movement Screen (FMS) scores and Y-Balance Test (YBT) composite scores were examined between BMI categories. In addition, the relationships between measures of obesity and movement efficiency were also examined. No significant differences in movement efficiency measures were identified between BMI categories (p > 0.05). However, significant bivariate correlations were identified between BMI (kg/m2) and Total FMS score (r = -0.235, p = 0.045), as well as between fat-free mass (FFM) and Total FMS score (r = -0.231, p = 0.049), when examined among all participants. BMI may influence measures of movement efficiency among firefighter recruits to a lesser extent than among other previously examined populations. Future research should examine the influence of other unexamined physiological variables on movement efficiency.

Detection of gas atoms with carbon nanotubes

PubMed Central

Arash, B.; Wang, Q.

2013-01-01

Owning to their unparalleled sensitivity resolution, nanomechanical resonators have excellent capabilities in design of nano-sensors for gas detection. The current challenge is to develop new designs of the resonators for differentiating distinct gas atoms with a recognizably high sensitivity. In this work, the characteristics of impulse wave propagation in carbon nanotube-based sensors are investigated using molecular dynamics simulations to provide a new method for detection of noble gases. A sensitivity index based on wave velocity shifts in a single-walled carbon nanotube, induced by surrounding gas atoms, is defined to explore the efficiency of the nano-sensor. The simulation results indicate that the nano-sensor is able to differentiate distinct noble gases at the same environmental temperature and pressure. The inertia and the strengthening effects by the gases on wave characteristics of carbon nanotubes are particularly discussed, and a continuum mechanics shell model is developed to interpret the effects.

Unified beam splitter of fused silica grating under the second Bragg incidence.

PubMed

Sun, Zhumei; Zhou, Changhe; Cao, Hongchao; Wu, Jun

2015-11-01

A unified design for a 1×2 beam splitter of dielectric rectangular transmission gratings under the second Bragg incidence is theoretically investigated for TE- and TM-polarized light. The empirical equations of the relative grating parameters (ratio of the absolute one to incidence wavelength) for this design are also obtained with the simplified modal method (SMM). The influences of polarization of incident light and relative grating parameters on the performance of the beam splitter are thoroughly studied based on the SMM and rigorous coupled-wave analysis. Two specific gratings are demonstrated with an even split and high diffraction efficiency (>94% for TE polarization and >97% for the TM counterpart). The unified profiles of the 1×2 beam splitter are independent from the incidence wavelength since the refractive index of fused silica is roughly a constant over a wide range of wavelengths, which should be promising for future applications.

Photonic crystal fiber technology for high-performance all-fiber monolithic ultrafast fiber amplifiers

NASA Astrophysics Data System (ADS)

Papior, Sidsel R.; Weirich, Johannes; Johansen, Mette M.; Jakobsen, Christian; Michieletto, Mattia; Triches, Marco; Kristensen, Torben; Olesen, Anders S.; Petersen, Christian; Andersen, Thomas V.; Maack, Martin D.; Alkeskjold, Thomas T.

2018-02-01

Photonic crystal fiber (PCF) technology for ultrafast fiber amplifiers traditionally uses air holes as key elements for large mode area (LMA) fiber designs. These air holes are crucial for the performance of high-end LMA PCFs, but makes splicing and interfacing more complex. To reduce this complexity in mid-range amplifiers, we present single-mode polarization-maintaining Yb-doped LMA PCFs without air holes for easier splicing into monolithic all-fiber amplifier designs. A 30 μm core all-solid spliceable PCF is presented, and amplification of 1064 nm light above 50 W with an optical to optical efficiency of 80 % is demonstrated. Furthermore, to demonstrate the excellent reliability of PCF based monolithic amplifiers, we demonstrate ultra-longterm performance data of > 35 khrs on a 14 μm core step-index type PCF amplifier with low long-term power degradation slope of < 1.5 % / 10,000 h.

Hadoop-based implementation of processing medical diagnostic records for visual patient system

NASA Astrophysics Data System (ADS)

Yang, Yuanyuan; Shi, Liehang; Xie, Zhe; Zhang, Jianguo

2018-03-01

We have innovatively introduced Visual Patient (VP) concept and method visually to represent and index patient imaging diagnostic records (IDR) in last year SPIE Medical Imaging (SPIE MI 2017), which can enable a doctor to review a large amount of IDR of a patient in a limited appointed time slot. In this presentation, we presented a new approach to design data processing architecture of VP system (VPS) to acquire, process and store various kinds of IDR to build VP instance for each patient in hospital environment based on Hadoop distributed processing structure. We designed this system architecture called Medical Information Processing System (MIPS) with a combination of Hadoop batch processing architecture and Storm stream processing architecture. The MIPS implemented parallel processing of various kinds of clinical data with high efficiency, which come from disparate hospital information system such as PACS, RIS LIS and HIS.

Damage level prediction of non-reshaped berm breakwater using ANN, SVM and ANFIS models

NASA Astrophysics Data System (ADS)

Mandal, Sukomal; Rao, Subba; N., Harish; Lokesha

2012-06-01

The damage analysis of coastal structure is very important as it involves many design parameters to be considered for the better and safe design of structure. In the present study experimental data for non-reshaped berm breakwater are collected from Marine Structures Laboratory, Department of Applied Mechanics and Hydraulics, NITK, Surathkal, India. Soft computing techniques like Artificial Neural Network (ANN), Support Vector Machine (SVM) and Adaptive Neuro Fuzzy Inference system (ANFIS) models are constructed using experimental data sets to predict the damage level of non-reshaped berm breakwater. The experimental data are used to train ANN, SVM and ANFIS models and results are determined in terms of statistical measures like mean square error, root mean square error, correla-tion coefficient and scatter index. The result shows that soft computing techniques i.e., ANN, SVM and ANFIS can be efficient tools in predicting damage levels of non reshaped berm breakwater.

A framework for reporting on human factor/usability studies of health information technologies.

PubMed

Peute, Linda W; Driest, Keiko F; Marcilly, Romaric; Bras Da Costa, Sabrina; Beuscart-Zephir, Marie-Catherine; Jaspers, Monique W M

2013-01-01

Increasingly, studies are being published on the potential negative effect of introducing poor designed Health Information Technology (HIT) into clinical settings, relating to technology-induced errors and adverse events. Academic research on HIT design and evaluation is an extremely important source of information in providing new insights into factors contributing to successful system (re)design efforts, system user-friendliness and usability issues and safety critical aspects of HIT design. However, these studies have been inconsistent and incomprehensive in their reporting, complicating the appraisal of outcomes, generalizability of study findings, meta-analysis and harmonization of the available evidence. To improve identification of type of use errors and safety related issues regarding design and implementation of HIT, consensus on issues to be reported on in scientific publications is a necessary step forward. This study presents the first approach to a framework providing a set of principles to follow for comprehensive and unambiguous reporting of HIT design and usability evaluation studies with the objective to reduce variation, improve on the publication reporting quality and proper indexation of these studies. This framework may be helpful in expanding the knowledge base not only concerning the application of Human Factors (HF)/Usability studies of HIT but also improve the knowledge base of how to (re)design and implement effective, efficient and safe HIT.

Setting of index system of environmental and economic accounting of water

NASA Astrophysics Data System (ADS)

Tan, Yarong

2017-10-01

To realize the quality advancement of integrated water management in China, a scientific and perfect index system of environmental and economic accounting should be built. At present, the water shortage in China becomes increasingly serious, which further highlights the importance of efficient water management and improving the index system of water economic accounting. Based on the internal structure of the new statistical method of environmental and economic accounting, this paper focuses on analyzing and discussing the index system which it should have.

Transmission of energy-saving efficiency from obese parents to their offspring: the Korean National Health and Nutrition Examination Survey 2007-2011.

PubMed

Kim, Y; Kim, H; Hong, Y-C

2016-04-01

Concerns of a growing obesity epidemic have increased since the association between obesity in parents and that in offspring was reported. However, the evidence regarding whether the energy-saving efficiency of obese parents is conveyed to their offspring and the duration of the expression of such transmitted efficiency is limited. We included 7647 matching sets of parent-offspring trios from South Korea. Multiple linear regression models were performed to estimate the energy-saving efficiency, as assessed by the associations between energy intake and obesity-related indices (waist-to-height ratio, waist circumference and body mass index z-score), and to compare the energy-saving efficiency of offspring of obese and non-obese parents. All analyses were based on a complex sample design and were stratified by gender and age. We identified a parental influence on obesity, that is, the more obese the parent, the higher the obesity-related indices of their offspring, in both genders and all age groups. The energy-saving efficiency of child offspring was highest when both parents were obese and lowest when both were non-obese; this difference was significant (P<0.05) with regard to the energy-saving efficiency of all types of intake studied, except fat. However, the energy-saving efficiency of obese and non-obese parents did not differ when their offspring were adolescents and adults. The critical window for transmission of energy-saving efficiency is limited to childhood. These findings suggest that children of obese parents should be more emphatically advised to maintain a balanced diet and to engage in regular physical activity.

[Application of simulated annealing method and neural network on optimizing soil sampling schemes based on road distribution].

PubMed

Han, Zong-wei; Huang, Wei; Luo, Yun; Zhang, Chun-di; Qi, Da-cheng

2015-03-01

Taking the soil organic matter in eastern Zhongxiang County, Hubei Province, as a research object, thirteen sample sets from different regions were arranged surrounding the road network, the spatial configuration of which was optimized by the simulated annealing approach. The topographic factors of these thirteen sample sets, including slope, plane curvature, profile curvature, topographic wetness index, stream power index and sediment transport index, were extracted by the terrain analysis. Based on the results of optimization, a multiple linear regression model with topographic factors as independent variables was built. At the same time, a multilayer perception model on the basis of neural network approach was implemented. The comparison between these two models was carried out then. The results revealed that the proposed approach was practicable in optimizing soil sampling scheme. The optimal configuration was capable of gaining soil-landscape knowledge exactly, and the accuracy of optimal configuration was better than that of original samples. This study designed a sampling configuration to study the soil attribute distribution by referring to the spatial layout of road network, historical samples, and digital elevation data, which provided an effective means as well as a theoretical basis for determining the sampling configuration and displaying spatial distribution of soil organic matter with low cost and high efficiency.

Index Compression and Efficient Query Processing in Large Web Search Engines

ERIC Educational Resources Information Center

Ding, Shuai

2013-01-01

The inverted index is the main data structure used by all the major search engines. Search engines build an inverted index on their collection to speed up query processing. As the size of the web grows, the length of the inverted list structures, which can easily grow to hundreds of MBs or even GBs for common terms (roughly linear in the size of…

Implementation of a thesaurus in an electronic photograph imaging system

NASA Astrophysics Data System (ADS)

Partlow, Denise

1995-11-01

A photograph imaging system presents a unique set of requirements for indexing and retrieving images, unlike a standard imaging system for written documents. This paper presents the requirements, technical design, and development results for a hierarchical ANSI standard thesaurus embedded into a photograph archival system. The thesaurus design incorporates storage reduction techniques, permits fast searches, and contains flexible indexing methods. It can be extended to many applications other than the retrieval of photographs. When photographic images are indexed into an electronic system, they are subject to a variety of indexing problems based on what the indexer `sees.' For instance, the indexer may categorize an image as a boat when others might refer to it as a ship, sailboat, or raft. The thesaurus will allow a user to locate images containing any synonym for boat, regardless of how the image was actually indexed. In addition to indexing problems, photos may need to be retrieved based on a broad category, for instance, flowers. The thesaurus allows a search for `flowers' to locate all images containing a rose, hibiscus, or daisy, yet still allow a specific search for an image containing only a rose. The technical design and method of implementation for such a thesaurus is presented. The thesaurus is implemented using an SQL relational data base management system that supports blobs, binary large objects. The design incorporates unique compression methods for storing the thesaurus words. Words are indexed to photographs using the compressed word and allow for very rapid searches, eliminating lengthy string matches.

Dry matter intake and feed efficiency profiles of 3 genotypes of Holstein-Friesian within pasture-based systems of milk production.

PubMed

Coleman, J; Berry, D P; Pierce, K M; Brennan, A; Horan, B

2010-09-01

The primary objective of the study was to quantify the effect of genetic improvement using the Irish total merit index (Economic Breeding Index) on dry matter intake and feed efficiency across lactation and to quantify the variation in performance among alternative definitions of feed efficiency. Three genotypes of Holstein-Friesian dairy cattle were established from within the Moorepark dairy research herd: 1) low Economic Breeding Index North American Holstein-Friesian representative of the Irish national average dairy cow, 2) high genetic merit North American Holstein-Friesian, and 3) high genetic merit New Zealand Holstein-Friesian. Animals from within each genotype were randomly allocated to 1 of 2 possible intensive pasture-based feed systems: 1) the Moorepark pasture system (2.64 cows/ha and 500 kg of concentrate supplement per cow per lactation) and 2) a high output per hectare pasture system (2.85 cows/ha and 1,200 kg of concentrate supplement per cow per lactation). A total of 128 and 140 spring-calving dairy cows were used during the years 2007 and 2008, respectively. Each group had an individual farmlet of 17 paddocks, and all groups were managed similarly throughout the study. The effects of genotype, feed system, and the interaction between genotype and feed system on dry matter intake, milk production, body weight, body condition score, and different definitions of feed efficiency were studied using mixed models with factorial arrangements of genotypes and feed systems accounting for the repeated cow records across years. No significant genotype-by-feed-system interactions were observed for any of the variables measured. Results showed that aggressive selection using the Irish Economic Breeding Index had no effect on dry matter intake across lactation when managed on intensive pasture-based systems of milk production, although the ranking of genotypes for feed efficiency differed depending on the definition of feed efficiency used. Performance of animals grouped on alternative definitions of feed efficiency showed that conventional definitions such as feed conversion efficiency or residual feed intake may be inappropriate measures of efficiency for lactating dairy cows. An alternative definition, residual solids production, is proposed. This definition of feed efficiency identifies animals that produce greater volumes of milk solids at similar levels of feed intake without excessive body tissue mobilization and with improved fertility performance. The results also suggest that although there are differences in feed efficiency between strains of Holstein-Friesian, there is also variation within genotypes so that improvements in feed efficiency can be realized if the appropriate definition of feed efficiency is incorporated into breeding programs. Copyright (c) 2010 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Scientometrics: Nature Index and Brazilian science.

PubMed

Silva, Valter

2016-09-01

A recent published newspaper article commented on the (lack of) quality of Brazilian science and its (in) efficiency. The newspaper article was based on a special issue of Nature and on a new resource for scientometrics called Nature Index. I show here arguments and sources of bias that, under the light of the principle in dubio pro reo, it is questionable to dispute the quality and efficiency of the Brazilian science on these grounds, as it was commented on the referred article. A brief overview of Brazilian science is provided for readers to make their own judgment.

Efficiency of compensatory orthodontic treatment of mild Class III malocclusion with two different bracket systems

PubMed Central

Aragón, Mônica L. C.; Bichara, Lívia M.; Flores-Mir, Carlos; Almeida, Guilherme; Normando, David

2017-01-01

ABSTRACT Objective: The purpose of this study was to assess the efficiency of compensatory orthodontic treatment of patients with mild Class III malocclusion with two preadjusted bracket systems. Method: Fifty-six matched patients consecutively treated for mild Class III malocclusion through compensatory dentoalveolar movements were retrospectively evaluated after analysis of orthodontic records. The sample was divided into two groups according to the brackets used: Group 1 = non-Class III compensated preadjusted brackets, Roth prescription (n = 28); Group 2 = compensated Class III preadjusted brackets, Capelozza III prescription (n = 28). Cephalometric analysis, number of appointments and missed appointments, months using Class III elastics, and bond/band failures were considered. Treatment time, Peer Assessment Rating (PAR) index at the beginning (PAR T1) and end of treatment (PAR T2) were used to calculate treatment efficiency. Comparison was performed using a MANOVA at p< 0.05. Results: Missed appointments, bond or band failures, number of months using the Class III intermaxillary elastics, and cephalometric measurements showed no statistically significant difference (p> 0.05) between groups. Patients treated with Roth brackets had a treatment time 7 months longer (p= 0.01). Significant improvement in the patient’s occlusion (PAR T2-T1) was observed for both groups without difference (p= 0.22). Conclusions: Orthodontic brackets designed for compensation of mild Class III malocclusions appear to be more efficient than non-compensated straight-wire prescription brackets. Treatment time for Class III patients treated with brackets designed for compensation was shorter than with Roth prescription and no difference in the quality of the occlusal outcome was observed. A prospective randomized study is suggested to provide a deeper look into this subject. PMID:29364379

Hidden Gratings in Holographic Liquid Crystal Polymer-Dispersed Liquid Crystal Films.

PubMed

De Sio, Luciano; Lloyd, Pamela F; Tabiryan, Nelson V; Bunning, Timothy J

2018-04-18

Dynamic diffraction gratings that are hidden in the field-off state are fabricated utilizing a room-temperature photocurable liquid crystal (LC) monomer and nematic LC (NLC) using holographic photopolymerization techniques. These holographic LC polymer-dispersed LCs (HLCPDLCs) are hidden because of the refractive index matching between the LC polymer and the NLC regions in the as-formed state (no E-field applied). Application of a moderate E-field (5 V/μm) generates a refractive index mismatch because of the NLC reorientation (along the E-field) generating high-diffraction efficiency transmission gratings. These dynamic gratings are characterized by morphological, optical, and electrooptical techniques. They exhibit a morphology made of oriented LC polymer regions (containing residual NLC) alternating with a two-phase region of an NLC and LC polymer. Unlike classic holographic polymer-dispersed LC gratings formed with a nonmesogenic monomer, there is index matching between the as-formed alternating regions of the grating. These HLCPDLCs exhibit broad band and high diffraction efficiency (≈90%) at the Bragg angle, are transparent to white light across the visible range because of the refractive index matching, and exhibit fast response times (1 ms). The ability of HLCPDLCs not to consume electrical power in the off state opens new possibilities for the realization of energy-efficient switchable photonic devices.

a Novel Approach of Indexing and Retrieving Spatial Polygons for Efficient Spatial Region Queries

NASA Astrophysics Data System (ADS)

Zhao, J. H.; Wang, X. Z.; Wang, F. Y.; Shen, Z. H.; Zhou, Y. C.; Wang, Y. L.

2017-10-01

Spatial region queries are more and more widely used in web-based applications. Mechanisms to provide efficient query processing over geospatial data are essential. However, due to the massive geospatial data volume, heavy geometric computation, and high access concurrency, it is difficult to get response in real time. Spatial indexes are usually used in this situation. In this paper, based on k-d tree, we introduce a distributed KD-Tree (DKD-Tree) suitbable for polygon data, and a two-step query algorithm. The spatial index construction is recursive and iterative, and the query is an in memory process. Both the index and query methods can be processed in parallel, and are implemented based on HDFS, Spark and Redis. Experiments on a large volume of Remote Sensing images metadata have been carried out, and the advantages of our method are investigated by comparing with spatial region queries executed on PostgreSQL and PostGIS. Results show that our approach not only greatly improves the efficiency of spatial region query, but also has good scalability, Moreover, the two-step spatial range query algorithm can also save cluster resources to support a large number of concurrent queries. Therefore, this method is very useful when building large geographic information systems.

Engineering of budesonide-loaded lipid-polymer hybrid nanoparticles using a quality-by-design approach.

PubMed

Leng, Donglei; Thanki, Kaushik; Fattal, Elias; Foged, Camilla; Yang, Mingshi

2017-08-25

Chronic obstructive pulmonary disease (COPD) is a complex disease, characterized by persistent airflow limitation and chronic inflammation. The purpose of this study was to design lipid-polymer hybrid nanoparticles (LPNs) loaded with the corticosteroid, budesonide, which could potentially be combined with small interfering RNA (siRNA) for COPD management. Here, we prepared LPNs based on the biodegradable polymer poly(dl-lactic-co-glycolic acid) (PLGA) and the cationic lipid dioleyltrimethylammonium propane (DOTAP) using a double emulsion solvent evaporation method. A quality-by-design (QbD) approach was adopted to define the optimal formulation parameters. The quality target product profile (QTPP) of the LPNs was identified based on risk assessment. Two critical formulation parameters (CFPs) were identified, including the theoretical budesonide loading and the theoretical DOTAP loading. The CFPs were linked to critical quality attributes (CQAs), which included the intensity-based hydrodynamic particle diameter (z-average), the polydispersity index (PDI), the zeta-potential, the budesonide encapsulation efficiency, the actual budesonide loading and the DOTAP encapsulation efficiency. A response surface methodology (RSM) was applied for the experimental design to evaluate the influence of the CFPs on the CQAs, and to identify the optimal operation space (OOS). All nanoparticle dispersions displayed monodisperse size distributions (PDI<0.2) with z-averages of approximately 150nm, suggesting that the size is not dependent on the investigated CFPs. In contrast, the zeta-potential was highly dependent on the theoretical DOTAP loading. Upon increased DOTAP loading, the zeta-potential reached a maximal point, after which it remained stable at the maximum value. This suggests that the LPN surface is covered by DOTAP, and that the DOTAP loading is saturable. The actual budesonide loading of the LPNs was mainly dependent on the initial amount of budesonide, and a clear positive effect was observed, which shows that the interaction between drug and PLGA increases when increasing the initial amount of budesonide. The OOS was modeled by applying the QTPP. The OOS had a budesonide encapsulation efficiency higher than 30%, a budesonide loading above 15μg budesonide/mg PLGA, a zeta-potential higher than 35mV and a DOTAP encapsulation efficiency above 50%. This study shows the importance of systematic formulation design for understanding the effect of formulation parameters on the characteristics of LPNs, eventually resulting in the identification of an OOS. Copyright © 2017 Elsevier B.V. All rights reserved.

Accuracy analysis and design of A3 parallel spindle head

NASA Astrophysics Data System (ADS)

Ni, Yanbing; Zhang, Biao; Sun, Yupeng; Zhang, Yuan

2016-03-01

As functional components of machine tools, parallel mechanisms are widely used in high efficiency machining of aviation components, and accuracy is one of the critical technical indexes. Lots of researchers have focused on the accuracy problem of parallel mechanisms, but in terms of controlling the errors and improving the accuracy in the stage of design and manufacturing, further efforts are required. Aiming at the accuracy design of a 3-DOF parallel spindle head(A3 head), its error model, sensitivity analysis and tolerance allocation are investigated. Based on the inverse kinematic analysis, the error model of A3 head is established by using the first-order perturbation theory and vector chain method. According to the mapping property of motion and constraint Jacobian matrix, the compensatable and uncompensatable error sources which affect the accuracy in the end-effector are separated. Furthermore, sensitivity analysis is performed on the uncompensatable error sources. The sensitivity probabilistic model is established and the global sensitivity index is proposed to analyze the influence of the uncompensatable error sources on the accuracy in the end-effector of the mechanism. The results show that orientation error sources have bigger effect on the accuracy in the end-effector. Based upon the sensitivity analysis results, the tolerance design is converted into the issue of nonlinearly constrained optimization with the manufacturing cost minimum being the optimization objective. By utilizing the genetic algorithm, the allocation of the tolerances on each component is finally determined. According to the tolerance allocation results, the tolerance ranges of ten kinds of geometric error sources are obtained. These research achievements can provide fundamental guidelines for component manufacturing and assembly of this kind of parallel mechanisms.

A cascadable circular concentrator with parallel compressed structure for increasing the energy density

NASA Astrophysics Data System (ADS)

Ku, Nai-Lun; Chen, Yi-Yung; Hsieh, Wei-Che; Whang, Allen Jong-Woei

2012-02-01

Due to the energy crisis, the principle of green energy gains popularity. This leads the increasing interest in renewable energy such as solar energy. Thus, how to collect the sunlight for indoor illumination becomes our ultimate target. With the environmental awareness increasing, we use the nature light as the light source. Then we start to devote the development of solar collecting system. The Natural Light Guiding System includes three parts, collecting, transmitting and lighting part. The idea of our solar collecting system design is a concept for combining the buildings with a combination of collecting modules. Therefore, we can use it anyplace where the sunlight can directly impinges on buildings with collecting elements. In the meantime, while collecting the sunlight with high efficiency, we can transmit the sunlight into indoor through shorter distance zone by light pipe where we needs the light. We proposed a novel design including disk-type collective lens module. With the design, we can let the incident light and exit light be parallel and compressed. By the parallel and compressed design, we make every output light become compressed in the proposed optical structure. In this way, we can increase the ratio about light compression, get the better efficiency and let the energy distribution more uniform for indoor illumination. By the definition of "KPI" as an performance index about light density as following: lm/(mm)2, the simulation results show that the proposed Concentrator is 40,000,000 KPI much better than the 800,000 KPI measured from the traditional ones.

Loteprednol Etabonate Nanoparticles: Optimization via Box-Behnken Design Response Surface Methodology and Physicochemical Characterization.

PubMed

Sah, Abhishek K; Suresh, Preeti K

2017-01-01

Abstract: The objective of the present work was to prepare and optimize the loteprednoletabonate (LE) loaded poly (D,L-lactide co-glycolide) (PLGA) polymer based nanoparticle carrier. The review on recent patents (US9006241, US20130224302A1, US2012/0028947A1) assisted in the selection of drug and polymer for designing nanoparticles for ocular delivery applications. The nanoparticles were prepared by solvent evaporation followed by high speed homogenization. Biodegradable polymer PLGA (50:50) grade was utilized to develop various formulations with different drug:polymer ratio. A Box-Behnken design with 33 factorial design was selected for the present study and 17 runs were carried out in totality. The influence of various process variables (viz., polymer concentration, homogenization speed and sonication time) on the characteristics of nanoparticles including the in vitro drug release profile were studied. The nanoparticulate formulations were evaluated for mean spherical diameter, polydispersity index (PDI), zeta potential, surface morphology, drug entrapment and in-vitro drug release profile. The entrapment efficiency, drug loading and mean particle size were found to be 96.31±1.68 %, 35.46±0.35 % and 167.6±2.1 nm respectively. The investigated process and formulation variables were found to have significant effect on the particle size, drug loading (DL), entrapment efficiency (EE), and in vitro drug release profile. A biphasic in vitro drug release profile was apparent from the optimized nanoparticles (NPs) for 24 hours. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Highly efficient pseudomorphic InGaAs/GaAs/AlGaAs single quantum well lasers for monolithic integration

NASA Technical Reports Server (NTRS)

Larsson, A.; Cody, J.; Forouhar, S.; Lang, R. J.

1990-01-01

Highly efficient ridge waveguide pseudomorphic single quantum well lasers, emitting at 980 nm, have been fabricated from an In(0.2)Ga(0.8)As/GaAs/AlGaAs graded-index separate confinement heterostructure grown by molecular beam epitaxy. The laterial index guiding provided by the ridge reduces the anomalously large lateral loss of optical power found in gain-guided structures, thereby reducing the internal loss by more than 50 percent. The low threshold current (7.6 mA) and high differential quantum efficiency (79 percent) obtained under continuous operation as well as the transparency of the GaAs substrate to the emitted radiation render these lasers attractive for Ga-As-based optoelectronic integration.

Electrically pumped edge-emitting photonic bandgap semiconductor laser

DOEpatents

Lin, Shawn-Yu; Zubrzycki, Walter J.

2004-01-06

A highly efficient, electrically pumped edge-emitting semiconductor laser based on a one- or two-dimensional photonic bandgap (PBG) structure is described. The laser optical cavity is formed using a pair of PBG mirrors operating in the photonic band gap regime. Transverse confinement is achieved by surrounding an active semiconductor layer of high refractive index with lower-index cladding layers. The cladding layers can be electrically insulating in the passive PBG mirror and waveguide regions with a small conducting aperture for efficient channeling of the injection pump current into the active region. The active layer can comprise a quantum well structure. The quantum well structure can be relaxed in the passive regions to provide efficient extraction of laser light from the active region.

Execution time supports for adaptive scientific algorithms on distributed memory machines

NASA Technical Reports Server (NTRS)

Berryman, Harry; Saltz, Joel; Scroggs, Jeffrey

1990-01-01

Optimizations are considered that are required for efficient execution of code segments that consists of loops over distributed data structures. The PARTI (Parallel Automated Runtime Toolkit at ICASE) execution time primitives are designed to carry out these optimizations and can be used to implement a wide range of scientific algorithms on distributed memory machines. These primitives allow the user to control array mappings in a way that gives an appearance of shared memory. Computations can be based on a global index set. Primitives are used to carry out gather and scatter operations on distributed arrays. Communications patterns are derived at runtime, and the appropriate send and receive messages are automatically generated.

Execution time support for scientific programs on distributed memory machines

NASA Technical Reports Server (NTRS)

Berryman, Harry; Saltz, Joel; Scroggs, Jeffrey

1990-01-01

Optimizations are considered that are required for efficient execution of code segments that consists of loops over distributed data structures. The PARTI (Parallel Automated Runtime Toolkit at ICASE) execution time primitives are designed to carry out these optimizations and can be used to implement a wide range of scientific algorithms on distributed memory machines. These primitives allow the user to control array mappings in a way that gives an appearance of shared memory. Computations can be based on a global index set. Primitives are used to carry out gather and scatter operations on distributed arrays. Communications patterns are derived at runtime, and the appropriate send and receive messages are automatically generated.

Requirements and principles for the implementation and construction of large-scale geographic information systems

NASA Technical Reports Server (NTRS)

Smith, Terence R.; Menon, Sudhakar; Star, Jeffrey L.; Estes, John E.

1987-01-01

This paper provides a brief survey of the history, structure and functions of 'traditional' geographic information systems (GIS), and then suggests a set of requirements that large-scale GIS should satisfy, together with a set of principles for their satisfaction. These principles, which include the systematic application of techniques from several subfields of computer science to the design and implementation of GIS and the integration of techniques from computer vision and image processing into standard GIS technology, are discussed in some detail. In particular, the paper provides a detailed discussion of questions relating to appropriate data models, data structures and computational procedures for the efficient storage, retrieval and analysis of spatially-indexed data.

Electric current focusing efficiency in a graphene electric lens.

PubMed

Mu, Weihua; Zhang, Gang; Tang, Yunqing; Wang, Wei; Ou-Yang, Zhongcan

2011-12-14

In the present work, we study theoretically the electron wave's focusing phenomenon in a single-layered graphene pn junction (PNJ) and obtain the electric current density distribution of graphene PNJ, which is in good agreement with the qualitative result in previous numerical calculations (Cheianov et al 2007 Science, 315, 1252). In addition, we find that, for a symmetric PNJ, 1/4 of total electric current radiated from the source electrode can be collected by the drain electrode. Furthermore, this ratio reduces to 3/16 in a symmetric graphene npn junction. Our results obtained by the present analytical method provide a general design rule for an electric lens based on negative refractory index systems. © 2011 IOP Publishing Ltd

Angle-resolved diffraction grating biosensor based on porous silicon

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

Lv, Changwu; Li, Peng; Jia, Zhenhong, E-mail: jzhh@xju.edu.cn

2016-03-07

In this study, an optical biosensor based on a porous silicon composite structure was fabricated using a simple method. This structure consists of a thin, porous silicon surface diffraction grating and a one-dimensional porous silicon photonic crystal. An angle-resolved diffraction efficiency spectrum was obtained by measuring the diffraction efficiency at a range of incident angles. The angle-resolved diffraction efficiency of the 2nd and 3rd orders was studied experimentally and theoretically. The device was sensitive to the change of refractive index in the presence of a biomolecule indicated by the shift of the diffraction efficiency spectrum. The sensitivity of this sensormore » was investigated through use of an 8 base pair antifreeze protein DNA hybridization. The shifts of the angle-resolved diffraction efficiency spectrum showed a relationship with the change of the refractive index, and the detection limit of the biosensor reached 41.7 nM. This optical device is highly sensitive, inexpensive, and simple to fabricate. Using shifts in diffraction efficiency spectrum to detect biological molecules has not yet been explored, so this study establishes a foundation for future work.« less

High-efficiency, 154  W CW, diode-pumped Raman fiber laser with brightness enhancement.

PubMed

Glick, Yaakov; Fromzel, Viktor; Zhang, Jun; Ter-Gabrielyan, Nikolay; Dubinskii, Mark

2017-01-20

We demonstrate a high-power, high-efficiency Raman fiber laser pumped directly by laser diode modules at 978 nm. 154 W of CW power were obtained at a wavelength of 1023 nm with an optical to optical efficiency of 65%. A commercial graded-index (GRIN) core fiber acts as the Raman fiber in a power oscillator configuration, which includes spectral selection to prevent generation of the second Stokes. In addition, brightness enhancement of the pump beam by a factor of 8.4 is attained due to the Raman gain distribution profile in the GRIN fiber. To the best of our knowledge this is the highest power and highest efficiency Raman fiber laser demonstrated in any configuration allowing brightness enhancement (i.e., in either cladding-pumped configuration or with GRIN fibers, excluding step-index core pumped), regardless of pumping scheme (i.e., either diode pumped or fiber laser pumped).

Measuring efficiency and productivity growth of new technology-based firms in business incubators: the Portuguese case study of Madan Parque.

PubMed

Grilo, A; Santos, J

2015-01-01

Business incubators can play a major role in helping to turn a business idea into a technology-based organization that is economically efficient. However, there is a shortage in the literature regarding the efficiency evaluation and productivity evolution of the new technology-based firms (NTBFs) in the incubation scope. This study develops a model based on the data envelopment analysis (DEA) methodology, which allows the incubated NTBFs to evaluate and improve the efficiency of their management. Moreover, the Malmquist index is used to examine productivity change. The index is decomposed into multiple components to give insights into the root sources of productivity change. The proposed model was applied in a case study with 13 NTBFs incubated. From that study, we conclude that inefficient firms invest excessively in research and development (R&D), and, on average, firms have a productivity growth in the period of study.

Measuring Efficiency and Productivity Growth of New Technology-Based Firms in Business Incubators: The Portuguese Case Study of Madan Parque

PubMed Central

Grilo, A.; Santos, J.

2015-01-01

Business incubators can play a major role in helping to turn a business idea into a technology-based organization that is economically efficient. However, there is a shortage in the literature regarding the efficiency evaluation and productivity evolution of the new technology-based firms (NTBFs) in the incubation scope. This study develops a model based on the data envelopment analysis (DEA) methodology, which allows the incubated NTBFs to evaluate and improve the efficiency of their management. Moreover, the Malmquist index is used to examine productivity change. The index is decomposed into multiple components to give insights into the root sources of productivity change. The proposed model was applied in a case study with 13 NTBFs incubated. From that study, we conclude that inefficient firms invest excessively in research and development (R&D), and, on average, firms have a productivity growth in the period of study. PMID:25874266

Hurst exponent and prediction based on weak-form efficient market hypothesis of stock markets

NASA Astrophysics Data System (ADS)

Eom, Cheoljun; Choi, Sunghoon; Oh, Gabjin; Jung, Woo-Sung

2008-07-01

We empirically investigated the relationships between the degree of efficiency and the predictability in financial time-series data. The Hurst exponent was used as the measurement of the degree of efficiency, and the hit rate calculated from the nearest-neighbor prediction method was used for the prediction of the directions of future price changes. We used 60 market indexes of various countries. We empirically discovered that the relationship between the degree of efficiency (the Hurst exponent) and the predictability (the hit rate) is strongly positive. That is, a market index with a higher Hurst exponent tends to have a higher hit rate. These results suggested that the Hurst exponent is useful for predicting future price changes. Furthermore, we also discovered that the Hurst exponent and the hit rate are useful as standards that can distinguish emerging capital markets from mature capital markets.

Indexing and Metatag Schemes for Web-Based Information Retrieval.

ERIC Educational Resources Information Center

Torok, Andrew G.

This paper reviews indexing theory and suggests that information retrieval can be significantly improved by applying basic indexing criteria. Indexing practices are described, including the three main types of indexes: pre-coordinate, post-coordinate, and variants of both. Design features of indexes are summarized, including accuracy, consistency,…

Optimization of infobutton design and Implementation: A systematic review.

PubMed

Teixeira, Miguel; Cook, David A; Heale, Bret S E; Del Fiol, Guilherme

2017-10-01

Infobuttons are clinical decision tools embedded in the electronic health record that attempt to link clinical data with context sensitive knowledge resources. We systematically reviewed technical approaches that contribute to improved infobutton design, implementation and functionality. We searched databases including MEDLINE, EMBASE, and the Cochrane Library database from inception to March 1, 2016 for studies describing the use of infobuttons. We selected full review comparative studies, usability studies, and qualitative studies examining infobutton design and implementation. We abstracted usability measures such as user satisfaction, impact, and efficiency, as well as prediction accuracy of infobutton content retrieval algorithms and infobutton adoption/interoperability. We found 82 original research studies on infobuttons. Twelve studies met criteria for detailed abstraction. These studies investigated infobutton interoperability (1 study); tools to help tailor infobutton functionality (1 study); interventions to improve user experience (7 studies); and interventions to improve content retrieval by improving prediction of relevant knowledge resources and information needs (3 studies). In-depth interviews with implementers showed the Health Level Seven (HL7) Infobutton standard to be simple and easy to implement. A usability study demonstrated the feasibility of a tool to help medical librarians tailor infobutton functionality. User experience studies showed that access to resources with which users are familiar increased user satisfaction ratings; and that links to specific subsections of drug monographs increased information seeking efficiency. However, none of the user experience improvements led to increased usage uptake. Recommender systems based on machine learning algorithms outperformed hand-crafted rules in the prediction of relevant resources and clinicians' information needs in a laboratory setting, but no studies were found using these techniques in clinical settings. Improved content indexing in one study led to improved content retrieval across three health care organizations. Best practice technical approaches to ensure optimal infobutton functionality, design and implementation remain understudied. The HL7 Infobutton standard has supported wide adoption of infobutton functionality among clinical information systems and knowledge resources. Limited evidence supports infobutton enhancements such as links to specific subtopics, configuration of optimal resources for specific tasks and users, and improved indexing and content coverage. Further research is needed to investigate user experience improvements to increase infobutton use and effectiveness. Copyright © 2017 Elsevier Inc. All rights reserved.

DUK - A Fast and Efficient Kmer Based Sequence Matching Tool

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

Li, Mingkun; Copeland, Alex; Han, James

2011-03-21

A new tool, DUK, is developed to perform matching task. Matching is to find whether a query sequence partially or totally matches given reference sequences or not. Matching is similar to alignment. Indeed many traditional analysis tasks like contaminant removal use alignment tools. But for matching, there is no need to know which bases of a query sequence matches which position of a reference sequence, it only need know whether there exists a match or not. This subtle difference can make matching task much faster than alignment. DUK is accurate, versatile, fast, and has efficient memory usage. It uses Kmermore » hashing method to index reference sequences and Poisson model to calculate p-value. DUK is carefully implemented in C++ in object oriented design. The resulted classes can also be used to develop other tools quickly. DUK have been widely used in JGI for a wide range of applications such as contaminant removal, organelle genome separation, and assembly refinement. Many real applications and simulated dataset demonstrate its power.« less

Efficient Lookup Table-Based Adaptive Baseband Predistortion Architecture for Memoryless Nonlinearity

NASA Astrophysics Data System (ADS)

Ba, Seydou N.; Waheed, Khurram; Zhou, G. Tong

2010-12-01

Digital predistortion is an effective means to compensate for the nonlinear effects of a memoryless system. In case of a cellular transmitter, a digital baseband predistorter can mitigate the undesirable nonlinear effects along the signal chain, particularly the nonlinear impairments in the radiofrequency (RF) amplifiers. To be practically feasible, the implementation complexity of the predistorter must be minimized so that it becomes a cost-effective solution for the resource-limited wireless handset. This paper proposes optimizations that facilitate the design of a low-cost high-performance adaptive digital baseband predistorter for memoryless systems. A comparative performance analysis of the amplitude and power lookup table (LUT) indexing schemes is presented. An optimized low-complexity amplitude approximation and its hardware synthesis results are also studied. An efficient LUT predistorter training algorithm that combines the fast convergence speed of the normalized least mean squares (NLMSs) with a small hardware footprint is proposed. Results of fixed-point simulations based on the measured nonlinear characteristics of an RF amplifier are presented.

Photonic ring resonator filters for astronomical OH suppression

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

Ellis, S. C.; Kuhlmann, S.; Kuehn, K.

Ring resonators provide a means of filtering specific wavelengths from a waveguide, and optionally dropping the filtered wavelengths into a second waveguide. Both of these features are potentially useful for astronomical instruments. In this paper we focus on their use as notch filters to remove the signal from atmospheric OH emission lines from astronomical spectra. We derive the design requirements for ring resonators for OH suppression from theory and finite difference time domain simulations. We find that rings with small radii (< 10 μm) are required to provide an adequate free spectral range, leading to high index contrast materials suchmore » as Si and Si 3N 4. Critically coupled rings with high self-coupling coefficients should provide the necessary Q factors, suppression depth, and throughput for efficient OH suppression, but will require post-inscription tuning of the coupling and the resonant wavelengths. The overall prospects for the use of ring resonators in astronomical instruments is promising, provided efficient fibre-chip coupling can be achieved.« less

Photonic ring resonator filters for astronomical OH suppression

DOE PAGES

Ellis, S. C.; Kuhlmann, S.; Kuehn, K.; ...

2017-01-01

Ring resonators provide a means of filtering specific wavelengths from a waveguide, and optionally dropping the filtered wavelengths into a second waveguide. Both of these features are potentially useful for astronomical instruments. In this paper we focus on their use as notch filters to remove the signal from atmospheric OH emission lines from astronomical spectra. We derive the design requirements for ring resonators for OH suppression from theory and finite difference time domain simulations. We find that rings with small radii (< 10 μm) are required to provide an adequate free spectral range, leading to high index contrast materials suchmore » as Si and Si 3N 4. Critically coupled rings with high self-coupling coefficients should provide the necessary Q factors, suppression depth, and throughput for efficient OH suppression, but will require post-inscription tuning of the coupling and the resonant wavelengths. The overall prospects for the use of ring resonators in astronomical instruments is promising, provided efficient fibre-chip coupling can be achieved.« less

Achievement of ultrahigh solar concentration with potential for efficient laser pumping.

PubMed

Gleckman, P

1988-11-01

Measurements are reported of the irradiance produced by a two-stage solar concentrator designed to approach the thermodynamic limit. Sunlight is collected by a 40.6-cm diam parabolic primary which forms a 0.98-cm diam image. The image is reconcentrated by a nonimaging refracting secondary with index n = 1.53 to a final aperture 1.27 mm in diameter. Thus the geometrical concentration ratio is 102, 000. The highest irradiance value achieved was 4.4 +/- 0.2 kW cm(-2), or 56,000 +/- 5000 suns, relative to a solar disk insolation of 800 W m(-2). This is greater than the previous peak solar irradiance record by nearly a factor of 3, and it is 68% of that existing at the solar surface itself. The efficiency with which we concentrated 55 W of sunlight to a small spot suggests that our two-stage system would be an excellent candidate for solar pumping of solid state lasers.

A review of ion and metal pollutants in urban green water infrastructures.

PubMed

Kabir, Md Imran; Daly, Edoardo; Maggi, Federico

2014-02-01

In urban environments, the breakdown of chemicals and pollutants, especially ions and metal compounds, can be favoured by green water infrastructures (GWIs). The overall aim of this review is to set the basis to model GWIs using deterministic approaches in contrast to empirical ones. If a better picture of chemicals and pollutant input and an improved understanding of hydrological and biogeochemical processes affecting these pollutants were known, GWIs could be designed to efficiently retain these pollutants for site-specific meteorological patterns and pollutant load. To this end, we surveyed the existing literature to retrieve a comprehensive dataset of anions and cations, and alkaline and transition metal pollutants incoming to urban environments. Based on this survey, we assessed the pollution load and ecological risk indexes for metals. The existing literature was then surveyed to review the metal retention efficiency of GWIs, and possible biogeochemical processes related to inorganic metal compounds were proposed that could be integrated in biogeochemical models of GWIs. © 2013.

Car Assembly Line Efficiency Improvement by Lean Principle

NASA Astrophysics Data System (ADS)

Sawassalung, Suwalee; Chutima, Parames

2017-06-01

This research aimed to increase the efficiency of actual working time to compare to design standard time ratio (DSTR) as per analysing process of Lean System of the assembly line in a car manufacturer in Thailand. Currently, the case study factory and its group of factories, which have many branches all over the world, have competed with each other on quality, delivered time and production cost. The production cost which can reduce without affecting quality and acceptable by clients is the manpower cost. The index of competition is DSTR. The factory now has DSTR of 6.13 and DSTR of the assembly department is 4.24 which is very high comparing to other departments. The low DSTR indicates that the factory has good quality. The ways to solve the problem are to apply the following tools, i.e. Lean principle, Value Stream Mapping (VSM), Waste Analysis and ECRS. After implementing the above tools, the results showed that DSTR decreased from 4.24 to 4.06 or 4.25%.

Monolithic crystalline cladding microstructures for efficient light guiding and beam manipulation in passive and active regimes.

PubMed

Jia, Yuechen; Cheng, Chen; Vázquez de Aldana, Javier R; Castillo, Gabriel R; Rabes, Blanca del Rosal; Tan, Yang; Jaque, Daniel; Chen, Feng

2014-08-07

Miniature laser sources with on-demand beam features are desirable devices for a broad range of photonic applications. Lasing based on direct-pump of miniaturized waveguiding active structures offers a low-cost but intriguing solution for compact light-emitting devices. In this work, we demonstrate a novel family of three dimensional (3D) photonic microstructures monolithically integrated in a Nd:YAG laser crystal wafer. They are produced by the femtosecond laser writing, capable of simultaneous light waveguiding and beam manipulation. In these guiding systems, tailoring of laser modes by both passive/active beam splitting and ring-shaped transformation are achieved by an appropriate design of refractive index patterns. Integration of graphene thin-layer as saturable absorber in the 3D laser structures allows for efficient passive Q-switching of tailored laser radiations which may enable miniature waveguiding lasers for broader applications. Our results pave a way to construct complex integrated passive and active laser circuits in dielectric crystals by using femtosecond laser written monolithic photonic chips.

Positioning matrix of economic efficiency and complexity: a case study in a university hospital.

PubMed

Ippolito, Adelaide; Viggiani, Vincenzo

2014-01-01

At the end of 2010, the Federico II University Hospital in Naples, Italy, initiated a series of discussions aimed at designing and applying a positioning matrix to its departments. This analysis was developed to create a tool able to extract meaningful information both to increase knowledge about individual departments and to inform the choices of general management during strategic planning. The name given to this tool was the positioning matrix of economic efficiency and complexity. In the matrix, the x-axis measures the ratio between revenues and costs, whereas the y-axis measures the index of complexity, thus showing "profitability" while bearing in mind the complexity of activities. By using the positioning matrix, it was possible to conduct a critical analysis of the characteristics of the Federico II University Hospital and to extract useful information for general management to use during strategic planning at the end of 2010 when defining medium-term objectives. Copyright © 2013 John Wiley & Sons, Ltd.

Reviews on current carbon emission reduction technologies and projects and their feasibilities on ships

NASA Astrophysics Data System (ADS)

Wang, Haibin; Zhou, Peilin; Wang, Zhongcheng

2017-06-01

Concern about global climate change is growing, and many projects and researchers are committed to reducing greenhouse gases from all possible sources. International Maritime (IMO) has set a target of 20% CO2 reduction from shipping by 2020 and also presented a series of carbon emission reduction methods, which are known as Energy Efficiency Design Index (EEDI) and Energy Efficiency Operation Indicator (EEOI). Reviews on carbon emission reduction from all industries indicate that, Carbon Capture and Storage (CCS) is an excellent solution to global warming. In this paper, a comprehensive literature review of EEDI and EEOI and CCS is conducted and involves reviewing current policies, introducing common technologies, and considering their feasibilities for marine activities, mainly shipping. Current projects are also presented in this paper, thereby illustrating that carbon emission reduction has been the subject of attention from all over the world. Two case ship studies indicate the economic feasibility of carbon emission reduction and provide a guide for CCS system application and practical installation on ships.

The heat rate index indicator

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

Lasasso, M.; Runyan, B.; Napoli, J.

1995-06-01

This paper describes a method of tracking unit performance through the use of a reference number called the Heat Rate Index Indicator. The ABB Power Plant Controls OTIS performance monitor is used to determine when steady load conditions exist and then to collect controllable and equipment loss data which significantly impact thermal efficiency. By comparing these loss parameters to those found during the previous heat balance, it is possible to develop a new adjusted heat rate curve. These impacts on heat rate are used to changes the shape of the tested heat rate curve by the appropriate percentages over amore » specified load range. Mathcad is used to determine the Heat Rate Index by integrating for the areas beneath the adjusted heat rate curve and a heat rate curve that represents the unit`s ideal heat rate curve is the Heat Rate Index. An index of 1.0 indicates that the unit is operating at an ideal efficiency, while an index of less than 1.0 indicates that the unit is operating at less than ideal conditions. A one per cent change in the Heat Rate Index is equivalent to a one percent change in heat rate. The new shape of the adjusted heat rate curve and the individual curves generated from the controllable and equipment loss parameters are useful for determining performance problems in specific load ranges.« less

Efficiency and Productivity of County-level Public Hospitals Based on the Data Envelopment Analysis Model and Malmquist Index in Anhui, China

PubMed Central

Li, Nian-Nian; Wang, Cun-Hui; Ni, Hong; Wang, Heng

2017-01-01

Background: China began to implement the national medical and health system and public hospital reforms in 2009 and 2012, respectively. Anhui Province is one of the four pilot provinces, and the medical reform measures received wide attention nationwide. The effectiveness of the above reform needs to get attention. This study aimed to master the efficiency and productivity of county-level public hospitals based on the data envelopment analysis (DEA) model and Malmquist index in Anhui, China, and then provide improvement measures for the future hospital development. Methods: We chose 12 country-level hospitals based on geographical distribution and the economic development level in Anhui Province. Relevant data that were collected in the field and then sorted were provided by the administrative departments of the hospitals. DEA models were used to calculate the dynamic efficiency and Malmquist index factors for the 12 institutions. Results: During 2010–2015, the overall average relative service efficiency of 12 county-level public hospitals was 0.926, and the number of hospitals achieved an effective DEA for each year from 2010 to 2015 was 4, 6, 7, 7, 6, and 8, respectively, as measured using DEA. During this same period, the average overall production efficiency was 0.983, and the total productivity factor had declined. The overall production efficiency of five hospitals was >1, and the rest are <1 between 2010 and 2015. Conclusions: In 2010–2015, the relative service efficiency of 12 county-level public hospitals in Anhui Province showed a decreasing trend, and the service efficiency of each hospital changed. In the past 6 years, although some hospitals have been effective, the efficiency of the county-level public hospitals in Anhui Province has not improved significantly, and the total factor productivity has not been effectively improved. County-level public hospitals need to combine their own reality to find their own deficiencies. PMID:29176142

Efficiency and Productivity of County-level Public Hospitals Based on the Data Envelopment Analysis Model and Malmquist Index in Anhui, China.

PubMed

Li, Nian-Nian; Wang, Cun-Hui; Ni, Hong; Wang, Heng

2017-12-05

China began to implement the national medical and health system and public hospital reforms in 2009 and 2012, respectively. Anhui Province is one of the four pilot provinces, and the medical reform measures received wide attention nationwide. The effectiveness of the above reform needs to get attention. This study aimed to master the efficiency and productivity of county-level public hospitals based on the data envelopment analysis (DEA) model and Malmquist index in Anhui, China, and then provide improvement measures for the future hospital development. We chose 12 country-level hospitals based on geographical distribution and the economic development level in Anhui Province. Relevant data that were collected in the field and then sorted were provided by the administrative departments of the hospitals. DEA models were used to calculate the dynamic efficiency and Malmquist index factors for the 12 institutions. During 2010-2015, the overall average relative service efficiency of 12 county-level public hospitals was 0.926, and the number of hospitals achieved an effective DEA for each year from 2010 to 2015 was 4, 6, 7, 7, 6, and 8, respectively, as measured using DEA. During this same period, the average overall production efficiency was 0.983, and the total productivity factor had declined. The overall production efficiency of five hospitals was >1, and the rest are <1 between 2010 and 2015. In 2010-2015, the relative service efficiency of 12 county-level public hospitals in Anhui Province showed a decreasing trend, and the service efficiency of each hospital changed. In the past 6 years, although some hospitals have been effective, the efficiency of the county-level public hospitals in Anhui Province has not improved significantly, and the total factor productivity has not been effectively improved. County-level public hospitals need to combine their own reality to find their own deficiencies.

How current ginning processes affect fiber length uniformity index

USDA-ARS?s Scientific Manuscript database

There is a need to develop cotton ginning methods that improve fiber characteristics that are compatible with the newer and more efficient spinning technologies. A literature search produced recent studies that described how current ginning processes affect HVI fiber length uniformity index. Resul...

An efficient 3D R-tree spatial index method for virtual geographic environments

NASA Astrophysics Data System (ADS)

Zhu, Qing; Gong, Jun; Zhang, Yeting

A three-dimensional (3D) spatial index is required for real time applications of integrated organization and management in virtual geographic environments of above ground, underground, indoor and outdoor objects. Being one of the most promising methods, the R-tree spatial index has been paid increasing attention in 3D geospatial database management. Since the existing R-tree methods are usually limited by their weakness of low efficiency, due to the critical overlap of sibling nodes and the uneven size of nodes, this paper introduces the k-means clustering method and employs the 3D overlap volume, 3D coverage volume and the minimum bounding box shape value of nodes as the integrative grouping criteria. A new spatial cluster grouping algorithm and R-tree insertion algorithm is then proposed. Experimental analysis on comparative performance of spatial indexing shows that by the new method the overlap of R-tree sibling nodes is minimized drastically and a balance in the volumes of the nodes is maintained.

Fast Localization in Large-Scale Environments Using Supervised Indexing of Binary Features.

PubMed

Youji Feng; Lixin Fan; Yihong Wu

2016-01-01

The essence of image-based localization lies in matching 2D key points in the query image and 3D points in the database. State-of-the-art methods mostly employ sophisticated key point detectors and feature descriptors, e.g., Difference of Gaussian (DoG) and Scale Invariant Feature Transform (SIFT), to ensure robust matching. While a high registration rate is attained, the registration speed is impeded by the expensive key point detection and the descriptor extraction. In this paper, we propose to use efficient key point detectors along with binary feature descriptors, since the extraction of such binary features is extremely fast. The naive usage of binary features, however, does not lend itself to significant speedup of localization, since existing indexing approaches, such as hierarchical clustering trees and locality sensitive hashing, are not efficient enough in indexing binary features and matching binary features turns out to be much slower than matching SIFT features. To overcome this, we propose a much more efficient indexing approach for approximate nearest neighbor search of binary features. This approach resorts to randomized trees that are constructed in a supervised training process by exploiting the label information derived from that multiple features correspond to a common 3D point. In the tree construction process, node tests are selected in a way such that trees have uniform leaf sizes and low error rates, which are two desired properties for efficient approximate nearest neighbor search. To further improve the search efficiency, a probabilistic priority search strategy is adopted. Apart from the label information, this strategy also uses non-binary pixel intensity differences available in descriptor extraction. By using the proposed indexing approach, matching binary features is no longer much slower but slightly faster than matching SIFT features. Consequently, the overall localization speed is significantly improved due to the much faster key point detection and descriptor extraction. It is empirically demonstrated that the localization speed is improved by an order of magnitude as compared with state-of-the-art methods, while comparable registration rate and localization accuracy are still maintained.

Noninvasive assessment of vascular function and hydraulic power and efficiency in pediatric Fontan patients.

PubMed

Myers, Kimberley A; Leung, Mande T; Terri Potts, M; Potts, James E; Sandor, George G S

2013-10-01

Invasive studies have shown that children with Fontan palliation have abnormal arterial stiffness, impedance, and hydraulic power and efficiency. The aim of this study was to assess these indexes noninvasively in a cohort of children with Fontan circulation using Doppler echocardiography and compare their results with those of healthy peers. This was a case-control study of 22 Fontan patients and 31 healthy control children. Using standard two-dimensional, M-mode, and Doppler echocardiographic imaging and carotid artery applanation tonometry, aortic flows, dimensions, and pulse-wave velocity were measured, and vascular impedance and arterial stiffness were calculated. Hydraulic power and efficiency were calculated from standard fluid dynamics formulae. The median age was similar between groups. Stroke volume index (39 vs 39 mL/min/m(2)) and cardiac index (2.6 vs 2.5 L/min/m(2)) were similar. Aortic cross-sectional area (3.3 vs 2.8 cm(2)), peak aortic flow (302 vs 261 cm(3)/sec), and myocardial performance index (0.47 vs 0.25) were higher and ejection fraction (50% vs 66%) was lower in Fontan patients. Input impedance (61 vs 83 dyne · sec/cm(5)/m(2)) was lower in Fontan patients. Pulse-wave velocity (488 vs 364 cm/sec), elastic pressure-strain modulus (305 vs 263 torr), and stiffness index (4.15 vs 3.04) were higher in Fontan patients. Total arterial compliance (1.29 vs 1.32 mL/torr/m(2)) and mean power (606 vs 527 mW/m(2)) were similar and total hydraulic power (716 vs 627 mW/m(2)) was higher in Fontan patients. Efficiency and the power cost per unit of forward flow were similar. Despite stiffer aortas, Fontan patients generate more hydraulic power associated with decreased ventricular function to achieve a similar hydraulic efficiency. In Fontan patients, therapy that is given to improve ventricular function may need to target vascular stiffness as well. This technique may be used to monitor the efficacy of therapeutic interventions. Copyright © 2013 American Society of Echocardiography. Published by Mosby, Inc. All rights reserved.

Aggregated Indexing of Biomedical Time Series Data

PubMed Central

Woodbridge, Jonathan; Mortazavi, Bobak; Sarrafzadeh, Majid; Bui, Alex A.T.

2016-01-01

Remote and wearable medical sensing has the potential to create very large and high dimensional datasets. Medical time series databases must be able to efficiently store, index, and mine these datasets to enable medical professionals to effectively analyze data collected from their patients. Conventional high dimensional indexing methods are a two stage process. First, a superset of the true matches is efficiently extracted from the database. Second, supersets are pruned by comparing each of their objects to the query object and rejecting any objects falling outside a predetermined radius. This pruning stage heavily dominates the computational complexity of most conventional search algorithms. Therefore, indexing algorithms can be significantly improved by reducing the amount of pruning. This paper presents an online algorithm to aggregate biomedical times series data to significantly reduce the search space (index size) without compromising the quality of search results. This algorithm is built on the observation that biomedical time series signals are composed of cyclical and often similar patterns. This algorithm takes in a stream of segments and groups them to highly concentrated collections. Locality Sensitive Hashing (LSH) is used to reduce the overall complexity of the algorithm, allowing it to run online. The output of this aggregation is used to populate an index. The proposed algorithm yields logarithmic growth of the index (with respect to the total number of objects) while keeping sensitivity and specificity simultaneously above 98%. Both memory and runtime complexities of time series search are improved when using aggregated indexes. In addition, data mining tasks, such as clustering, exhibit runtimes that are orders of magnitudes faster when run on aggregated indexes. PMID:27617298

Simplified design of thin-film polarizing beam splitter using embedded symmetric trilayer stack.

PubMed

Azzam, R M A

2011-07-01

An analytically tractable design procedure is presented for a polarizing beam splitter (PBS) that uses frustrated total internal reflection and optical tunneling by a symmetric LHL trilayer thin-film stack embedded in a high-index prism. Considerable simplification arises when the refractive index of the high-index center layer H matches the refractive index of the prism and its thickness is quarter-wave. This leads to a cube design in which zero reflection for the p polarization is achieved at a 45° angle of incidence independent of the thicknesses of the identical symmetric low-index tunnel layers L and L. Arbitrarily high reflectance for the s polarization is obtained at subwavelength thicknesses of the tunnel layers. This is illustrated by an IR Si-cube PBS that uses an embedded ZnS-Si-ZnS trilayer stack.

Quasi-mosaicity of (311) planes in silicon and its use in a Laue lens with high-focusing power

NASA Astrophysics Data System (ADS)

Camattari, Riccardo; Paternò, Gianfranco; Bellucci, Valerio; Guidi, Vincenzo

2014-12-01

(311) curved planes can be exploited for efficiently focus hard X-rays. With this purpose, a self-standing bent crystal was manufactured at the Sensor and Semiconductor Laboratory of Ferrara (Italy). The crystal was designed as an optical component for a X-ray concentrator such as a Laue lens. The curvature of (311) planes was obtained through the quasi-mosaic effect. The diffraction efficiency of the sample was tested at the Institut Laue Langevin of Grenoble (France) by using a collimated monochromatic X-ray beam. This was the first prove of the diffraction properties of (311) quasi-mosaic planes. Diffraction efficiency resulted 35 % with a 182 keV X-ray beam, in agreement with the theoretical expectation. It corresponded to a reflectivity of 33 %. While the chosen orientation is not the most performing lying of planes, it can be used, in addition to smaller-index planes, in order to raise the total effective area of a Laue lens. To quantify it, a Laue lens based on quasi-mosaic silicon and germanium crystals, exploiting (111), (422) and (311) diffracting planes, was achieved and simulated with the LaueGen code.

Electrokinetic Analysis of Energy Harvest from Natural Salt Gradients in Nanochannels.

PubMed

He, Yuhui; Huang, Zhuo; Chen, Bowei; Tsutsui, Makusu; Shui Miao, Xiang; Taniguchi, Masateru

2017-10-13

The Gibbs free energy released during the mixing of river and sea water has been illustrated as a promising source of clean and renewable energy. Reverse electrodialysis (RED) is one major strategy to gain electrical power from this natural salinity, and recently by utilizing nanochannels a novel mode of this approach has shown improved power density and energy converting efficiency. In this work, we carry out an electrokinetic analysis of the work extracted from RED in the nanochannels. First, we outline the exclusion potential effect induced by the inhomogeneous distribution of extra-counterions along the channel axis. This effect is unique in nanochannel RED and how to optimize it for energy harvesting is the central topic of this work. We then discuss two important indexes of performance, which are the output power density and the energy converting efficiency, and their dependence on the nanochannel parameters such as channel material and geometry. In order to yield maximized output electrical power, we propose a device design by stepwise usage of the saline bias, and the lengths of the nanochannels are optimized to achieve the best trade-off between the input thermal power and the energy converting efficiency.

Designing long-term fish community assessments in connecting channels: Lessons from the Saint Marys River

USGS Publications Warehouse

Schaeffer, Jeff; Rogers, Mark W.; Fielder, David G.; Godby, Neal; Bowen, Anjanette K.; O'Connor, Lisa; Parrish, Josh; Greenwood, Susan; Chong, Stephen; Wright, Greg

2014-01-01

Long-term surveys are useful in understanding trends in connecting channel fish communities; a gill net assessment in the Saint Marys River performed periodically since 1975 is the most comprehensive connecting channels sampling program within the Laurentian Great Lakes. We assessed efficiency of that survey, with intent to inform development of assessments at other connecting channels. We evaluated trends in community composition, effort versus estimates of species richness, ability to detect abundance changes for four species, and effects of subsampling yellow perch catches on size and age-structure metrics. Efficiency analysis revealed low power to detect changes in species abundance, whereas reduced effort could be considered to index species richness. Subsampling simulations indicated that subsampling would have allowed reliable estimates of yellow perch (Perca flavescens) population structure, while greatly reducing the number of fish that were assigned ages. Analyses of statistical power and efficiency of current sampling protocols are useful for managers collecting and using these types of data as well as for the development of new monitoring programs. Our approach provides insight into whether survey goals and objectives were being attained and can help evaluate ability of surveys to answer novel questions that arise as management strategies are refined.

Systematic Approach for the Formulation and Optimization of Solid Lipid Nanoparticles of Efavirenz by High Pressure Homogenization Using Design of Experiments for Brain Targeting and Enhanced Bioavailability

PubMed Central

Gupta, Shweta; Kesarla, Rajesh; Chotai, Narendra; Misra, Ambikanandan

2017-01-01

The nonnucleoside reverse transcriptase inhibitors, used for the treatment of HIV infections, are reported to have low bioavailability pertaining to high first-pass metabolism, high protein binding, and enzymatic metabolism. They also show low permeability across blood brain barrier. The CNS is reported to be the most important HIV reservoir site. In the present study, solid lipid nanoparticles of efavirenz were prepared with the objective of providing increased permeability and protection of drug due to biocompatible lipidic content and nanoscale size and thus developing formulation having potential for enhanced bioavailability and brain targeting. Solid lipid nanoparticles were prepared by high pressure homogenization technique using a systematic approach of design of experiments (DoE) and evaluated for particle size, polydispersity index, zeta potential, and entrapment efficiency. Particles of average size 108.5 nm having PDI of 0.172 with 64.9% entrapment efficiency were produced. Zeta potential was found to be −21.2 mV and the formulation was found stable. The in-vivo pharmacokinetic studies revealed increased concentration of the drug in brain, as desired, when administered through intranasal route indicating its potential for an attempt towards complete eradication of HIV and cure of HIV-infected patients. PMID:28243600

Integrating GIS, cellular automata, and genetic algorithm in urban spatial optimization: a case study of Lanzhou

NASA Astrophysics Data System (ADS)

Xu, Xibao; Zhang, Jianming; Zhou, Xiaojian

2006-10-01

This paper presents a model integrating GIS, cellular automata (CA) and genetic algorithm (GA) in urban spatial optimization. The model involves three objectives of the maximization of land-use efficiency, the maximization of urban spatial harmony and appropriate proportion of each land-use type. CA submodel is designed with standard Moore neighbor and three transition rules to maximize the land-use efficiency and urban spatial harmony, according to the land-use suitability and spatial harmony index. GA submodel is designed with four constraints and seven steps for the maximization of urban spatial harmony and appropriate proportion of each land-use type, including encoding, initializing, calculating fitness, selection, crossover, mutation and elitism. GIS is used to prepare for the input data sets for the model and perform spatial analysis on the results, while CA and GA are integrated to optimize urban spatial structure, programmed with Matlab 7 and coupled with GIS loosely. Lanzhou, a typical valley-basin city with fast urban development, is chosen as the case study. At the end, a detail analysis and evaluation of the spatial optimization with the model are made, and it proves to be a powerful tool in optimizing urban spatial structure and make supplement for urban planning and policy-makers.

Selenium Interlayer for High-Efficiency Multijunction Solar Cell

NASA Technical Reports Server (NTRS)

Landis, Geoffrey A (Inventor)

2015-01-01

A multi junction solar cell is provided and includes multiple semiconducting layers and an interface layer disposed between the multiple semiconducting layers. The interface layer is made from an interface bonding material that has a refractive index such that a ratio of a refractive index of each of the multiple semiconducting layers to the refractive index of the interface bonding material is less than or equal to 1.5.

Selenium Interlayer for High-Efficiency Multijunction Solar Cell

NASA Technical Reports Server (NTRS)

Landis, Geoffrey A. (Inventor)

2016-01-01

A multi-junction solar cell is provided and includes multiple semiconducting layers and an interface layer disposed between the multiple semiconducting layers. The interface layer is made from an interface bonding material that has a refractive index such that a ratio of a refractive index of each of the multiple semiconducting layers to the refractive index of the interface bonding material is less than or equal to 1.5.

Efficient protein structure search using indexing methods

PubMed Central

2013-01-01

Understanding functions of proteins is one of the most important challenges in many studies of biological processes. The function of a protein can be predicted by analyzing the functions of structurally similar proteins, thus finding structurally similar proteins accurately and efficiently from a large set of proteins is crucial. A protein structure can be represented as a vector by 3D-Zernike Descriptor (3DZD) which compactly represents the surface shape of the protein tertiary structure. This simplified representation accelerates the searching process. However, computing the similarity of two protein structures is still computationally expensive, thus it is hard to efficiently process many simultaneous requests of structurally similar protein search. This paper proposes indexing techniques which substantially reduce the search time to find structurally similar proteins. In particular, we first exploit two indexing techniques, i.e., iDistance and iKernel, on the 3DZDs. After that, we extend the techniques to further improve the search speed for protein structures. The extended indexing techniques build and utilize an reduced index constructed from the first few attributes of 3DZDs of protein structures. To retrieve top-k similar structures, top-10 × k similar structures are first found using the reduced index, and top-k structures are selected among them. We also modify the indexing techniques to support θ-based nearest neighbor search, which returns data points less than θ to the query point. The results show that both iDistance and iKernel significantly enhance the searching speed. In top-k nearest neighbor search, the searching time is reduced 69.6%, 77%, 77.4% and 87.9%, respectively using iDistance, iKernel, the extended iDistance, and the extended iKernel. In θ-based nearest neighbor serach, the searching time is reduced 80%, 81%, 95.6% and 95.6% using iDistance, iKernel, the extended iDistance, and the extended iKernel, respectively. PMID:23691543

Efficient protein structure search using indexing methods.

PubMed

Kim, Sungchul; Sael, Lee; Yu, Hwanjo

2013-01-01

Understanding functions of proteins is one of the most important challenges in many studies of biological processes. The function of a protein can be predicted by analyzing the functions of structurally similar proteins, thus finding structurally similar proteins accurately and efficiently from a large set of proteins is crucial. A protein structure can be represented as a vector by 3D-Zernike Descriptor (3DZD) which compactly represents the surface shape of the protein tertiary structure. This simplified representation accelerates the searching process. However, computing the similarity of two protein structures is still computationally expensive, thus it is hard to efficiently process many simultaneous requests of structurally similar protein search. This paper proposes indexing techniques which substantially reduce the search time to find structurally similar proteins. In particular, we first exploit two indexing techniques, i.e., iDistance and iKernel, on the 3DZDs. After that, we extend the techniques to further improve the search speed for protein structures. The extended indexing techniques build and utilize an reduced index constructed from the first few attributes of 3DZDs of protein structures. To retrieve top-k similar structures, top-10 × k similar structures are first found using the reduced index, and top-k structures are selected among them. We also modify the indexing techniques to support θ-based nearest neighbor search, which returns data points less than θ to the query point. The results show that both iDistance and iKernel significantly enhance the searching speed. In top-k nearest neighbor search, the searching time is reduced 69.6%, 77%, 77.4% and 87.9%, respectively using iDistance, iKernel, the extended iDistance, and the extended iKernel. In θ-based nearest neighbor serach, the searching time is reduced 80%, 81%, 95.6% and 95.6% using iDistance, iKernel, the extended iDistance, and the extended iKernel, respectively.

An Investigation of the Differences and Similarities between Generated Small-World Networks for Right- and Left-Hand Motor Imageries.

PubMed

Zhang, Jiang; Li, Yuyao; Chen, Huafu; Ding, Jurong; Yuan, Zhen

2016-11-04

In this study, small-world network analysis was performed to identify the similarities and differences between functional brain networks for right- and left-hand motor imageries (MIs). First, Pearson correlation coefficients among the nodes within the functional brain networks from healthy subjects were calculated. Then, small-world network indicators, including the clustering coefficient, the average path length, the global efficiency, the local efficiency, the average node degree, and the small-world index, were generated for the functional brain networks during both right- and left-hand MIs. We identified large differences in the small-world network indicators between the functional networks during MI and in the random networks. More importantly, the functional brain networks underlying the right- and left-hand MIs exhibited similar small-world properties in terms of the clustering coefficient, the average path length, the global efficiency, and the local efficiency. By contrast, the right- and left-hand MI brain networks showed differences in small-world characteristics, including indicators such as the average node degree and the small-world index. Interestingly, our findings also suggested that the differences in the activity intensity and range, the average node degree, and the small-world index of brain networks between the right- and left-hand MIs were associated with the asymmetry of brain functions.

Design of embedded system to determine liquid refractive index based on ultrasonic sensor using an ATMega328

NASA Astrophysics Data System (ADS)

Radiyonoa, Y.; Surantoro, S.; Pujayanto, P.; Budiharti, R.; Respati, Y. S.; Saputro, D. E.

2018-05-01

The occurrence of the broken pencil shadow into a glass of water becomes an interesting matter to be learned. The students of senior high school still find difficulty in determining liquid refractive index. To overcome this problem, it needs to develop an experimental tool to determine liquid refractive index by utilizing the newest technology. It is expected to be useful for students. This study is aimed to (1) make the design of physics learning experimental tool determinant of a liquid refractive index assisted by microcontroller based on ultrasonic sensors ATMega328 (2) explain the working principle and experimental result of liquid refractive indexing instrument assisted with ATMega328 microcontroller based ultrasonic sensor. This research used the experimental method. The result of the research shows design of physics learning experimental tool determinant of a liquid refractive index assisted by microcontroller based on ultrasonic sensors ATMega328 that has relative counting mistake of 0.36% on the measurement of aquades liquid refractive index, relative mistake of 0.18% on the 5% NaCl measurement, 0.24% on 5% glucose, and relative mistake of 0.50% on the measurement of 5 % fructose liquid refractive index. It has been created a proper device to be used in determining liquid refractive index.

On the Certain Topological Indices of Titania Nanotube TiO2[m, n

NASA Astrophysics Data System (ADS)

Javaid, M.; Liu, Jia-Bao; Rehman, M. A.; Wang, Shaohui

2017-07-01

A numeric quantity that characterises the whole structure of a molecular graph is called the topological index that predicts the physical features, chemical reactivities, and boiling activities of the involved chemical compound in the molecular graph. In this article, we give new mathematical expressions for the multiple Zagreb indices, the generalised Zagreb index, the fourth version of atom-bond connectivity (ABC4) index, and the fifth version of geometric-arithmetic (GA5) index of TiO2[m, n]. In addition, we compute the latest developed topological index called by Sanskruti index. At the end, a comparison is also included to estimate the efficiency of the computed indices. Our results extended some known conclusions.

Optimally designed narrowband guided-mode resonance reflectance filters for mid-infrared spectroscopy

PubMed Central

Liu, Jui-Nung; Schulmerich, Matthew V.; Bhargava, Rohit; Cunningham, Brian T.

2011-01-01

An alternative to the well-established Fourier transform infrared (FT-IR) spectrometry, termed discrete frequency infrared (DFIR) spectrometry, has recently been proposed. This approach uses narrowband mid-infrared reflectance filters based on guided-mode resonance (GMR) in waveguide gratings, but filters designed and fabricated have not attained the spectral selectivity (≤ 32 cm−1) commonly employed for measurements of condensed matter using FT-IR spectroscopy. With the incorporation of dispersion and optical absorption of materials, we present here optimal design of double-layer surface-relief silicon nitride-based GMR filters in the mid-IR for various narrow bandwidths below 32 cm−1. Both shift of the filter resonance wavelengths arising from the dispersion effect and reduction of peak reflection efficiency and electric field enhancement due to the absorption effect show that the optical characteristics of materials must be taken into consideration rigorously for accurate design of narrowband GMR filters. By incorporating considerations for background reflections, the optimally designed GMR filters can have bandwidth narrower than the designed filter by the antireflection equivalence method based on the same index modulation magnitude, without sacrificing low sideband reflections near resonance. The reported work will enable use of GMR filters-based instrumentation for common measurements of condensed matter, including tissues and polymer samples. PMID:22109445

Optimizing the dermal accumulation of a tazarotene microemulsion using skin deposition modeling.

PubMed

Nasr, Maha; Abdel-Hamid, Sameh

2016-01-01

It is well known that microemulsions are mainly utilized for their transdermal rather than their dermal drug delivery potential due to their low viscosity, and the presence of penetration enhancing surfactants and co-surfactants. Applying quality by design (QbD) principles, a tazarotene microemulsion formulation for local skin delivery was optimized by creating a control space. Critical formulation factors (CFF) were oil, surfactant/co-surfactant (SAA/CoS), and water percentages. Critical quality attributes (CQA) were globular size, microemulsion viscosity, tazarotene skin deposition, permeation, and local accumulation efficiency index. Increasing oil percentage increased globular size, while the opposite occurred regarding SAA/CoS, (p = 0.001). Microemulsion viscosity was reduced by increasing oil and water percentages (p < 0.05), due to the inherent high viscosity of the utilized SAA/CoS. Drug deposition in the skin was reduced by increasing SAA/CoS due to the increased hydrophilicity and viscosity of the system, but increased by increasing water due to hydration effect (p = 0.009). Models with very good fit were generated, predicting the effect of CFF on globular size, microemulsion viscosity, and drug deposition. A combination of 40% oil and 45% SAA/CoS showed the maximum drug deposition of 75.1%. Clinical skin irritation study showed that the aforementioned formula was safe for topical use. This article suggests that applying QbD tools such as experimental design is an efficient tool for drug product design.

Possibility-based robust design optimization for the structural-acoustic system with fuzzy parameters

NASA Astrophysics Data System (ADS)

Yin, Hui; Yu, Dejie; Yin, Shengwen; Xia, Baizhan

2018-03-01

The conventional engineering optimization problems considering uncertainties are based on the probabilistic model. However, the probabilistic model may be unavailable because of the lack of sufficient objective information to construct the precise probability distribution of uncertainties. This paper proposes a possibility-based robust design optimization (PBRDO) framework for the uncertain structural-acoustic system based on the fuzzy set model, which can be constructed by expert opinions. The objective of robust design is to optimize the expectation and variability of system performance with respect to uncertainties simultaneously. In the proposed PBRDO, the entropy of the fuzzy system response is used as the variability index; the weighted sum of the entropy and expectation of the fuzzy response is used as the objective function, and the constraints are established in the possibility context. The computations for the constraints and objective function of PBRDO are a triple-loop and a double-loop nested problem, respectively, whose computational costs are considerable. To improve the computational efficiency, the target performance approach is introduced to transform the calculation of the constraints into a double-loop nested problem. To further improve the computational efficiency, a Chebyshev fuzzy method (CFM) based on the Chebyshev polynomials is proposed to estimate the objective function, and the Chebyshev interval method (CIM) is introduced to estimate the constraints, thereby the optimization problem is transformed into a single-loop one. Numerical results on a shell structural-acoustic system verify the effectiveness and feasibility of the proposed methods.

Photonic metamaterials: a new class of materials for manipulating light waves

PubMed Central

Iwanaga, Masanobu

2012-01-01

A decade of research on metamaterials (MMs) has yielded great progress in artificial electromagnetic materials in a wide frequency range from microwave to optical frequencies. This review outlines the achievements in photonic MMs that can efficiently manipulate light waves from near-ultraviolet to near-infrared in subwavelength dimensions. One of the key concepts of MMs is effective refractive index, realizing values that have not been obtained in ordinary solid materials. In addition to the high and low refractive indices, negative refractive indices have been reported in some photonic MMs. In anisotropic photonic MMs of high-contrast refractive indices, the polarization and phase of plane light waves were efficiently transformed in a well-designed manner, enabling remarkable miniaturization of linear optical devices such as polarizers, wave plates and circular dichroic devices. Another feature of photonic MMs is the possibility of unusual light propagation, paving the way for a new subfield of transfer optics. MM lenses having super-resolution and cloaking effects were introduced by exploiting novel light-propagating modes. Here, we present a new approach to describing photonic MMs definitely by resolving the electromagnetic eigenmodes. Two representative photonic MMs are addressed: the so-called fishnet MM slabs, which are known to have effective negative refractive index, and a three-dimensional MM based on a multilayer of a metal and an insulator. In these photonic MMs, we elucidate the underlying eigenmodes that induce unusual light propagations. Based on the progress of photonic MMs, the future potential and direction are discussed. PMID:27877512

Application of symbolic computations to the constitutive modeling of structural materials

NASA Technical Reports Server (NTRS)

Arnold, Steven M.; Tan, H. Q.; Dong, X.

1990-01-01

In applications involving elevated temperatures, the derivation of mathematical expressions (constitutive equations) describing the material behavior can be quite time consuming, involved and error-prone. Therefore intelligent application of symbolic systems to faciliate this tedious process can be of significant benefit. Presented here is a problem oriented, self contained symbolic expert system, named SDICE, which is capable of efficiently deriving potential based constitutive models in analytical form. This package, running under DOE MACSYMA, has the following features: (1) potential differentiation (chain rule), (2) tensor computations (utilizing index notation) including both algebraic and calculus; (3) efficient solution of sparse systems of equations; (4) automatic expression substitution and simplification; (5) back substitution of invariant and tensorial relations; (6) the ability to form the Jacobian and Hessian matrix; and (7) a relational data base. Limited aspects of invariant theory were also incorporated into SDICE due to the utilization of potentials as a starting point and the desire for these potentials to be frame invariant (objective). The uniqueness of SDICE resides in its ability to manipulate expressions in a general yet pre-defined order and simplify expressions so as to limit expression growth. Results are displayed, when applicable, utilizing index notation. SDICE was designed to aid and complement the human constitutive model developer. A number of examples are utilized to illustrate the various features contained within SDICE. It is expected that this symbolic package can and will provide a significant incentive to the development of new constitutive theories.

Combination of submicroemulsion and phospholipid complex for novel delivery of ursodeoxycholic acid.

PubMed

Ma, Yue-Qin; Li, Gang; Xu, Jiang-Hong; Zhang, Jing; Zhang, Zeng-Zhu; Xiao, Han-Yang; Li, Xian-Fei

2014-05-01

The objective of this study was to prepare and characterize ursodeoxycholic acid submicron emulsion (UA-SME) loaded with ursodeoxycholic acid phytosomes (UA-PS) and optimize the process variables. A screening experiment with response surface methodology with Box-Behnken design (BBD) was used to optimize the process parameters of UA-SME. The blood concentrations of UA after oral administration of UA-SME and UA coarse drug were assayed. The optimum process conditions were finally obtained by using a desirability function. It was found that stirring velocity, homogenization pressure and homogenization cycles were the most important variables that affected the particles size, polydispersity index and entrapment efficiency of UA-SME. Results showed that the optimum stirring velocity, homogenization pressure and cycles were 16 000 rpm, 60 MPa and 10 cycles, respectively. The mean diameter, polydispersity index and entrapment efficiency of UA-SME were 251.9 nm, 0.241 and 74.36%, respectively. Pharmacokinetic parameters of UA and UA-SME in rats were Tmax 2.215 and 1.489 h, Cmax 0.0364 and 0.1562 μg/mL, AUC0-∞ 3.682 and 13.756 μg h/mL, respectively. The bioavailability of UA in rats was significantly different (p < 0.05) after oral administration of UA-SME compared to those of UA coarse drug. This was due to improvement of the hydrophilicity and lipophilic property of UA-SME.

Application of the central composite design to optimize the preparation of novel micelles of harmine.

PubMed

Bei, Yong-Yan; Zhou, Xiao-Feng; You, Ben-Gang; Yuan, Zhi-Qiang; Chen, Wei-Liang; Xia, Peng; Liu, Yang; Jin, Yong; Hu, Xiao-Juan; Zhu, Qiao-Ling; Zhang, Chun-Ge; Zhang, Xue-Nong; Zhang, Liang

2013-01-01

Lactose-palmitoyl-trimethyl-chitosan (Lac-TPCS), a novel amphipathic self-assembled polymer, was synthesized for administration of insoluble drugs to reduce their adverse effects. The central composite design was used to study the preparation technique of harmine (HM)-loaded self-assembled micelles based on Lac-TPCS (Lac-TPCS/HM). Three preparation methods and single factors were screened, including solvent type, HM amount, hydration volume, and temperature. The optimal preparation technique was identified after investigating the influence of two independent factors, namely, HM amount and hydration volume, on four indexes, ie, encapsulation efficiency (EE), drug-loading amount (LD), particle size, and polydispersity index (PDI). Analysis of variance showed a high coefficient of determination of 0.916 to 0.994, thus ensuring a satisfactory adjustment of the predicted prescription. The maximum predicted values of the optimal prescription were 91.62%, 14.20%, 183.3 nm, and 0.214 for EE, LD, size, and PDI, respectively, when HM amount was 1.8 mg and hydration volume was 9.6 mL. HM-loaded micelles were successfully characterized by Fourier-transform infrared spectroscopy, differential scanning calorimetry, X-ray diffraction, and a fluorescence-quenching experiment. Sustained release of Lac-TPCS/HM reached 65.3% in 72 hours at pH 7.4, while free HM released about 99.7% under the same conditions.

Supercontinuum generation in square photonic crystal fiber with nearly zero ultra-flattened chromatic dispersion and fabrication tolerance analysis

NASA Astrophysics Data System (ADS)

Begum, Feroza; Namihira, Yoshinori; Kinjo, Tatsuya; Kaijage, Shubi

2011-02-01

This paper presents a simple index-guiding square photonic crystal fiber (SPCF) where the core is surrounded by air holes with two different diameters. The proposed design is simulated through an efficient full-vector modal solver based on the finite difference method with anisotropic perfectly matched layers absorbing boundary condition. The nearly zero ultra-flattened dispersion SPCF with low confinement loss, small effective area as well as broadband supercontinuum (SC) spectra is targeted. Numerical results show that the designed SPCF has been achieved at a nearly zero ultra-flattened dispersion of 0 ± 0.25 ps/(nm·km) in a wavelength range of 1.38 μm to 1.89 μm (510 nm band) which covers E, S, C, L and U communication bands, a low confinement loss of less than 10 -7 dB/m in a wavelength range of 1.3 μm to 2.0 μm and a wide SC spectrum (FWHM = 450 nm) by using picosecond pulses at a center wavelength of 1.55 μm. We then analyze the sensitivity of chromatic dispersion to small variations from the optimum value of specific structural parameters. The proposed index-guiding SPCF can be applicable in supercontinuum generation (SCG) covering such diverse fields as spectroscopy applications and telecommunication dense wavelength division multiplexing (DWDM) sources.

Learning Efficiency versus Low IQ and/or Teachers' Ratings as Predictors of Reading Ability of "Mentally Defective" Children: A Longitudinal Study.

ERIC Educational Resources Information Center

Gupta, R. M.

1985-01-01

Low IQ should not be deemed as an index of poor learning ability. Information about middle school children's learning efficiency as measured by the Learning Efficiency Test Battery was found to be more useful for predicting reading ability than conventional types of assessment. (Author/RM)

Impact of the Local Public Hospital Reform on the Efficiency of Medium-Sized Hospitals in Japan: An Improved Slacks-Based Measure Data Envelopment Analysis Approach.

PubMed

Zhang, Xing; Tone, Kaoru; Lu, Yingzhe

2018-04-01

To assess the change in efficiency and total factor productivity (TFP) of the local public hospitals in Japan after the local public hospital reform launched in late 2007, which was aimed at improving the financial capability and operational efficiency of hospitals. Secondary data were collected from the Ministry of Internal Affairs and Communications on 213 eligible medium-sized hospitals, each operating 100-400 beds from FY2006 to FY2011. The improved slacks-based measure nonoriented data envelopment analysis models (Quasi-Max SBM nonoriented DEA models) were used to estimate dynamic efficiency score and Malmquist Index. The dynamic efficiency measure indicated an efficiency gain in the first several years of the reform and then was followed by a decrease. Malmquist Index analysis showed a significant decline in the TFP between 2006 and 2011. The financial improvement of medium-sized hospitals was not associated with enhancement of efficiency. Hospital efficiency was not significantly different among ownership structure and law-application system groups, but it was significantly affected by hospital location. The results indicate a need for region-tailored health care policies and for a more comprehensive reform to overcome the systemic constraints that might contribute to the decline of the TFP. © Health Research and Educational Trust.

Optimization of Micro-Spec, an Ultra-Compact High-Performance Spectrometer for Far-Infrared Astronomy

NASA Astrophysics Data System (ADS)

Cataldo, Giuseppe; Moseley, S. H.; Wollack, E.; Hsieh, W.; Huang, W.; Stevenson, T.

2013-06-01

Micro-Spec (µ-Spec) is a high-sensitivity direct-detection spectrometer operating in the far-infrared and submillimeter regime. When combined with a cryogenic telescope, it provides an enabling technology for studying the epoch of reionization and initial galaxy formation. As a direct-detection spectrometer, µ-Spec can provide high sensitivity under the low background conditions provided by cryogenic telescopes such as the space infrared telescope for cosmology and astrophysics SPICA. The µ-Spec modules use low-loss superconducting microstrip transmission lines implemented on a single 4-inch-diameter wafer. Such a dramatic size reduction is enabled by the use of silicon, a material with an index of refraction about three times that of vacuum, which thus allows the microstrip lines to be one third their vacuum length. Using a large number of modules as well as reducing the negative effects of stray light also contributes positively to the enhanced sensitivity of such an instrument. µ-Spec can be compared to a grating spectrometer, in which the phase retardation generated by the reflection from the grating grooves is instead produced by propagation through transmission lines of different length. The µ-Spec optical design is based on the stigmatization and minimization of the light path function in a two-dimensional diffractive region. The power collected through a broadband antenna is progressively divided by binary microstrip power dividers. The position of the radiators is selected to provide zero phase errors at two stigmatic points, and a third stigmatic point is generated by introducing a differential phase shift in each radiator. To optimize the overall efficiency of the instrument, the emitters are directed to the center of the focal surface. A point design was developed for initial demonstration. Because of losses to other diffraction orders, the efficiency of the design presented is about 30%. Design variations on this implementation are illustrated which can lead to near-unit efficiency and will be the basis of future instruments. Measurements are being conducted to validate the designs.

C-A1-03: Considerations in the Design and Use of an Oracle-based Virtual Data Warehouse

PubMed Central

Bredfeldt, Christine; McFarland, Lela

2011-01-01

Background/Aims The amount of clinical data available for research is growing exponentially. As it grows, increasing the efficiency of both data storage and data access becomes critical. Relational database management systems (rDBMS) such as Oracle are ideal solutions for managing longitudinal clinical data because they support large-scale data storage and highly efficient data retrieval. In addition, they can greatly simplify the management of large data warehouses, including security management and regular data refreshes. However, the HMORN Virtual Data Warehouse (VDW) was originally designed based on SAS datasets, and this design choice has a number of implications for both the design and use of an Oracle-based VDW. From a design standpoint, VDW tables are designed as flat SAS datasets, which do not take full advantage of Oracle indexing capabilities. From a data retrieval standpoint, standard VDW SAS scripts do not take advantage of SAS pass-through SQL capabilities to enable Oracle to perform the processing required to narrow datasets to the population of interest. Methods Beginning in 2009, the research department at Kaiser Permanente in the Mid-Atlantic States (KPMA) has developed an Oracle-based VDW according to the HMORN v3 specifications. In order to take advantage of the strengths of relational databases, KPMA introduced an interface layer to the VDW data, using views to provide access to standardized VDW variables. In addition, KPMA has developed SAS programs that provide access to SQL pass-through processing for first-pass data extraction into SAS VDW datasets for processing by standard VDW scripts. Results We discuss both the design and performance considerations specific to the KPMA Oracle-based VDW. We benchmarked performance of the Oracle-based VDW using both standard VDW scripts and an initial pre-processing layer to evaluate speed and accuracy of data return. Conclusions Adapting the VDW for deployment in an Oracle environment required minor changes to the underlying structure of the data. Further modifications of the underlying data structure would lead to performance enhancements. Maximally efficient data access for standard VDW scripts requires an extra step that involves restricting the data to the population of interest at the data server level prior to standard processing.

IR GRIN optics: design and fabrication

NASA Astrophysics Data System (ADS)

Gibson, Daniel; Bayya, Shyam; Nguyen, Vinh; Sanghera, Jas; Kotov, Mikhail; McClain, Collin; Deegan, John; Lindberg, George; Unger, Blair; Vizgaitis, Jay

2017-06-01

Infrared (IR) transmitting gradient index (GRIN) materials have been developed for broad-band IR imaging. This material is derived from the diffusion of homogeneous chalcogenide glasses has good transmission for all IR wavebands. The optical properties of the IR-GRIN materials are presented and the fabrication and design methodologies are discussed. Modeling and optimization of the diffusion process is exploited to minimize the deviation of the index profile from the design profile. Fully diffused IR-GRIN blanks with Δn of 0.2 are demonstrated with deviation errors of +/-0.01 refractive index units.

Content Analysis of Research Trends in Instructional Design Models: 1999-2014

ERIC Educational Resources Information Center

Göksu, Idris; Özcan, Kursat Volkan; Çakir, Recep; Göktas, Yuksel

2017-01-01

This study examines studies on instructional design models by applying content analysis. It covers 113 papers published in 44 international Social Science Citation Index (SSCI) and Science Citation Index (SCI) journals. Studies on instructional design models are explored in terms of journal of publication, preferred model, country where the study…

A Comprehensive System of Energy Intensity Indicators for the U.S.: Methods, Data and Key Trends

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

Belzer, David B.

2014-08-31

This report describes a comprehensive system of energy intensity indicators for the United States that has been developed for the Department of Energy’s Office of Energy Efficiency and Renewable Energy (EERE) over the past decade. This system of indicators is hierarchical in nature, beginning with detailed indexes of energy intensity for various sectors of the economy, which are ultimately aggregated to an overall energy intensity index for the economy as a whole. The aggregation of energy intensity indexes to higher levels in the hierarchy is performed with a version of the Log Mean Divisia Index (LMDI) method. Based upon themore » data and methods in the system of indicators, the economy-wide energy intensity index shows a decline of about 14% in 2010 relative to a 1985 base year. Discussion of energy intensity indicators for each of the broad end-use sectors of the economy—residential, commercial, industrial, and transportation—is presented in the report. An analysis of recent changes in the efficiency of electricity generation in the U.S. is also included. A detailed appendix describes the data sources and methodology behind the energy intensity indicators for each sector.« less

Boosting the FM-Index on the GPU: Effective Techniques to Mitigate Random Memory Access.

PubMed

Chacón, Alejandro; Marco-Sola, Santiago; Espinosa, Antonio; Ribeca, Paolo; Moure, Juan Carlos

2015-01-01

The recent advent of high-throughput sequencing machines producing big amounts of short reads has boosted the interest in efficient string searching techniques. As of today, many mainstream sequence alignment software tools rely on a special data structure, called the FM-index, which allows for fast exact searches in large genomic references. However, such searches translate into a pseudo-random memory access pattern, thus making memory access the limiting factor of all computation-efficient implementations, both on CPUs and GPUs. Here, we show that several strategies can be put in place to remove the memory bottleneck on the GPU: more compact indexes can be implemented by having more threads work cooperatively on larger memory blocks, and a k-step FM-index can be used to further reduce the number of memory accesses. The combination of those and other optimisations yields an implementation that is able to process about two Gbases of queries per second on our test platform, being about 8 × faster than a comparable multi-core CPU version, and about 3 × to 5 × faster than the FM-index implementation on the GPU provided by the recently announced Nvidia NVBIO bioinformatics library.

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

Belzer, David B.; Bender, Sadie R.; Cort, Katherine A.

This report provides an update to a previously published (Rev 1) report that describes a comprehensive system of energy intensity indicators for the United States that has been developed for the Department of Energy’s Office of Energy Efficiency and Renewable Energy (EERE) over the past decade. This system of indicators is hierarchical in nature, beginning with detailed indexes of energy intensity for various sectors of the economy, which are ultimately aggregated to an overall energy intensity index for the economy as a whole. The aggregation of energy intensity indexes to higher levels in the hierarchy is performed with a versionmore » of the Log Mean Divisia index (LMDI) method. Based upon the data and methods in the system of indicators, the economy-wide energy intensity index shows a decline of about 14% in 2011 relative to a 1985 base year. Discussion of energy intensity indicators for each of the broad end-use sectors of the economy—residential, commercial, industrial, and transportation—is presented in the report. An analysis of recent changes in the efficiency of electricity generation in the U.S. is also included. A detailed appendix describes the data sources and methodology behind the energy intensity indicators for each sector.« less

Orbital-angular-momentum mode-group multiplexed transmission over a graded-index ring-core fiber based on receive diversity and maximal ratio combining

NASA Astrophysics Data System (ADS)

Zhang, Junwei; Zhu, Guoxuan; Liu, Jie; Wu, Xiong; Zhu, Jiangbo; Du, Cheng; Luo, Wenyong; Chen, Yujie; Yu, Siyuan

2018-02-01

An orbital-angular-momentum (OAM) mode-group multiplexing (MGM) scheme based on a graded-index ring-core fiber (GIRCF) is proposed, in which a single-input two-output (or receive diversity) architecture is designed for each MG channel and simple digital signal processing (DSP) is utilized to adaptively resist the mode partition noise resulting from random intra-group mode crosstalk. There is no need of complex multiple-input multiple-output (MIMO) equalization in this scheme. Furthermore, the signal-to-noise ratio (SNR) of the received signals can be improved if a simple maximal ratio combining (MRC) technique is employed on the receiver side to efficiently take advantage of the diversity gain of receiver. Intensity-modulated direct-detection (IM-DD) systems transmitting three OAM mode groups with total 100-Gb/s discrete multi-tone (DMT) signals over a 1-km GIRCF and two OAM mode groups with total 40-Gb/s DMT signals over an 18-km GIRCF are experimentally demonstrated, respectively, to confirm the feasibility of our proposed OAM-MGM scheme.

Integrated polymer-based Mach-Zehnder interferometer label-free streptavidin biosensor compatible with injection molding.

PubMed

Bruck, R; Melnik, E; Muellner, P; Hainberger, R; Lämmerhofer, M

2011-05-15

We report the development of a Mach-Zehnder interferometer biosensor based on a high index contrast polymer material system and the demonstration of label-free online measurement of biotin-streptavidin binding on the sensor surface. The surface of the polyimide waveguide core layer was functionalized with 3-mercaptopropyl trimethoxy silane and malemide tagged biotin. Several concentrations of Chromeon 642-streptavidin dissolved in phosphate buffered saline solution were rinsed over the functionalized sensor surface by means of a fluidic system and the biotin-streptavidin binding process was observed in the output signal of the interferometer at a wavelength of 1310 nm. Despite the large wavelength and the comparatively low surface sensitivity of the sensor system due to the low index contrast in polymer material systems compared to inorganic material systems, we were able to resolve streptavidin concentrations of down to 0.1 μg/ml. The polymer-based optical sensor design is fully compatible with cost-efficient mass production technologies such as injection molding and spin coating, which makes it an attractive alternative to inorganic optical sensors. Copyright © 2011 Elsevier B.V. All rights reserved.

Efficient statistical tests to compare Youden index: accounting for contingency correlation.

PubMed

Chen, Fangyao; Xue, Yuqiang; Tan, Ming T; Chen, Pingyan

2015-04-30

Youden index is widely utilized in studies evaluating accuracy of diagnostic tests and performance of predictive, prognostic, or risk models. However, both one and two independent sample tests on Youden index have been derived ignoring the dependence (association) between sensitivity and specificity, resulting in potentially misleading findings. Besides, paired sample test on Youden index is currently unavailable. This article develops efficient statistical inference procedures for one sample, independent, and paired sample tests on Youden index by accounting for contingency correlation, namely associations between sensitivity and specificity and paired samples typically represented in contingency tables. For one and two independent sample tests, the variances are estimated by Delta method, and the statistical inference is based on the central limit theory, which are then verified by bootstrap estimates. For paired samples test, we show that the estimated covariance of the two sensitivities and specificities can be represented as a function of kappa statistic so the test can be readily carried out. We then show the remarkable accuracy of the estimated variance using a constrained optimization approach. Simulation is performed to evaluate the statistical properties of the derived tests. The proposed approaches yield more stable type I errors at the nominal level and substantially higher power (efficiency) than does the original Youden's approach. Therefore, the simple explicit large sample solution performs very well. Because we can readily implement the asymptotic and exact bootstrap computation with common software like R, the method is broadly applicable to the evaluation of diagnostic tests and model performance. Copyright © 2015 John Wiley & Sons, Ltd.

Effects of noninvasive ventilation on sleep outcomes in amyotrophic lateral sclerosis.

PubMed

Katzberg, Hans D; Selegiman, Adam; Guion, Lee; Yuan, Nancy; Cho, Sungho C; Katz, Jonathan S; Miller, Robert G; So, Yuen T

2013-04-15

The objective was to study the effects on noninvasive ventilation on sleep outcomes in patient with ALS, specifically oxygenation and overall sleep quality. Patients with ALS who met criteria for initiation of NIV were studied with a series of 2 home PSG studies, one without NIV and a follow-up study while using NIV. Primary outcome was a change in the maximum overnight oxygen saturation; secondary outcomes included change in mean overnight oxygen saturation, apnea and hypopnea indexes, sleep latency, sleep efficiency, sleep arousals, and sleep architecture. A total of 94 patients with ALS were screened for eligibility; 15 were enrolled; and 12 completed study procedures. Maximum overnight oxygen saturation improved by 7.0% (p = 0.01) and by 6.7% during REM sleep (p = 0.02) with NIV. Time spent below 90% oxygen saturation was also significant-ly better with NIV (30% vs 19%, p < 0.01), and there was trend for improvement in mean overnight saturation (1.5%, p = 0.06). Apnea index (3.7 to 0.7), hypopnea index (6.2 to 5.7), and apnea hypopnea index (9.8 to 6.3) did not significantly improve after introducing NIV. NIV had no effect on sleep efficiency (mean change 10%), arousal index (7 to 12), or sleep stage distribution (Friedman chi-squared = 0.40). NIV improved oxygenation but showed no significant effects on sleep efficiency, sleep arousals, restful sleep, or sleep architecture. The net impact of these changes for patients deserves further study in a larger group of ALS patients.

Reflection based Extraordinary Optical Transmission Fiber Optic Probe for Refractive Index Sensing.

PubMed

Lan, Xinwei; Cheng, Baokai; Yang, Qingbo; Huang, Jie; Wang, Hanzheng; Ma, Yinfa; Shi, Honglan; Xiao, Hai

2014-03-31

Fiber optic probes for chemical sensing based on the extraordinary optical transmission (EOT) phenomenon are designed and fabricated by perforating subwavelength hole arrays on the gold film coated optical fiber endface. The device exhibits a red shift in response to the surrounding refractive index increases with high sensitivity, enabling a reflection-based refractive index sensor with a compact and simple configuration. By choosing the period of hole arrays, the sensor can be designed to operate in the near infrared telecommunication wavelength range, where the abundant source and detectors are available for easy instrumentation. The new sensor probe is demonstrated for refractive index measurement using refractive index matching fluids. The sensitivity reaches 573 nm/RIU in the 1.333~1.430 refractive index range.

3-D photo-patterning of refractive index structures in photosensitive thin film materials

DOEpatents

Potter, Jr., Barrett George; Potter, Kelly Simmons

2002-01-01

A method of making a three-dimensional refractive index structure in a photosensitive material using photo-patterning. The wavelengths at which a photosensitive material exhibits a change in refractive index upon exposure to optical radiation is first determined and then a portion of the surface of the photosensitive material is optically irradiated at a wavelength at which the photosensitive material exhibits a change in refractive index using a designed illumination system to produce a three-dimensional refractive index structure. The illumination system can be a micro-lenslet array, a macroscopic refractive lens array, or a binary optic phase mask. The method is a single-step, direct-write procedure to produce a designed refractive index structure.

Efficiency and multifractality analysis of CSI 300 based on multifractal detrending moving average algorithm

NASA Astrophysics Data System (ADS)

Zhou, Weijie; Dang, Yaoguo; Gu, Rongbao

2013-03-01

We apply the multifractal detrending moving average (MFDMA) to investigate and compare the efficiency and multifractality of 5-min high-frequency China Securities Index 300 (CSI 300). The results show that the CSI 300 market becomes closer to weak-form efficiency after the introduction of CSI 300 future. We find that the CSI 300 is featured by multifractality and there are less complexity and risk after the CSI 300 index future was introduced. With the shuffling, surrogating and removing extreme values procedures, we unveil that extreme events and fat-distribution are the main origin of multifractality. Besides, we discuss the knotting phenomena in multifractality, and find that the scaling range and the irregular fluctuations for large scales in the Fq(s) vs s plot can cause a knot.

Effective holographic recordings in the photopolymer nanocomposites with functionalized silica nanoparticle and polyurethane matrix

NASA Astrophysics Data System (ADS)

Han, Samsook; Lee, Muncheul; Kim, Byung Kyu

2011-11-01

Effective holographic nanocomposites were developed by the surface-functionalized silica nanoparticles and two acrylate monomers/polyurethane (PU) matrix polymer. The functionalization was done with silane compounds carrying long alkyl chain or vinyl group. We evaluated the holographic nanocomposite films by the diffraction efficiency, volume shrinkage, optical loss, and the film morphology. It was found that acrylate monomers/PU system gave higher diffraction efficiency than those of two monomers due to the high refractive index mismatch between the acrylate-rich and PU-rich regions. With the modification of silica particle, up to 35% of particle loading was possible to give a maximum diffraction efficiency of 93.6% for a film of 20 μm in thickness, along with improved refractive index modulation and the sensitivity.

Trading efficiency for effectiveness in similarity-based indexing for image databases

NASA Astrophysics Data System (ADS)

Barros, Julio E.; French, James C.; Martin, Worthy N.; Kelly, Patrick M.

1995-11-01

Image databases typically manage feature data that can be viewed as points in a feature space. Some features, however, can be better expressed as a collection of points or described by a probability distribution function (PDF) rather than as a single point. In earlier work we introduced a similarity measure and a method for indexing and searching the PDF descriptions of these items that guarantees an answer equivalent to sequential search. Unfortunately, certain properties of the data can restrict the efficiency of that method. In this paper we extend that work and examine trade-offs between efficiency and answer quality or effectiveness. These trade-offs reduce the amount of work required during a search by reducing the number of undesired items fetched without excluding an excessive number of the desired ones.

Theoretical optimum of implant positional index design.

PubMed

Semper, W; Kraft, S; Krüger, T; Nelson, K

2009-08-01

Rotational freedom of the implant-abutment connection influences its screw joint stability; for optimization, influential factors need to be evaluated based on a previously developed closed formula. The underlying hypothesis is that the manufacturing tolerances, geometric pattern, and dimensions of the index do not influence positional stability. We used the dimensions of 5 commonly used implant systems with a clearance of 20 microm to calculate the extent of rotational freedom; a 3D simulation (SolidWorks) validated the analytical findings. Polygonal positional indices showed the highest degrees of rotational freedom. The polygonal profile displayed higher positional stability than the polygons, but less positional accuracy than the cam-groove connection. Features of a maximal rotation-safe positional index were determined. The analytical calculation of rotational freedom of implant positional indices is possible. Rotational freedom is dependent on the geometric design of the index and may be decreased by incorporating specific aspects into the positional index design.

Scaling and efficiency determine the irreversible evolution of a market

PubMed Central

Baldovin, F.; Stella, A. L.

2007-01-01

In setting up a stochastic description of the time evolution of a financial index, the challenge consists in devising a model compatible with all stylized facts emerging from the analysis of financial time series and providing a reliable basis for simulating such series. Based on constraints imposed by market efficiency and on an inhomogeneous-time generalization of standard simple scaling, we propose an analytical model which accounts simultaneously for empirical results like the linear decorrelation of successive returns, the power law dependence on time of the volatility autocorrelation function, and the multiscaling associated to this dependence. In addition, our approach gives a justification and a quantitative assessment of the irreversible character of the index dynamics. This irreversibility enters as a key ingredient in a novel simulation strategy of index evolution which demonstrates the predictive potential of the model.