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1

Real time Faraday spectrometer  

SciTech Connect

This invention uses a dipole magnet to bend the path of a charged particle beam. As the deflected particles exit the magnet, they are spatially dispersed in the bend-plane of the magnet according to their respective momenta and pass to a plurality of chambers having Faraday probes positioned therein. Both the current and energy distribution of the particles is then determined by the non-intersecting Faraday probes located along the chambers. The Faraday probes are magnetically isolated from each other by thin metal walls of the chambers, effectively providing real time current-versus-energy particle measurements.

Smith, Jr., Tommy E. (Fremont, CA); Struve, Kenneth W. (Albuquerque, NM); Colella, Nicholas J. (Livermore, CA)

1991-01-01

2

Real time Faraday spectrometer  

Microsoft Academic Search

This invention is comprised of a charged particle spectrometer that contains a detection system which embodies the benefits of both foil-light emissions and faraday cups, yet it does not interfere with the particle beam. 5 Figs. (GHH)

T. E. Jr. Smith; K. W. Struve; N. J. Colella

1990-01-01

3

An Interferometric Approach to Time Resolved Faraday Rotation Measurements  

NASA Astrophysics Data System (ADS)

Time Resolved Faraday Rotation (TRFR) is an optical pump-probe technique used to detect electron spin precession about an external magnetic field in semiconductors. In TRFR a net electron magnetic moment can induce small rotations in the polarization of the probe beam, which are detected through a polarizing cube beam splitter and two balanced photodiodes. We present a new approach that divides the probe beam into two orthogonally polarized arms of a free-space Mach-Zender interferometer where one arm contains the sample being studied. Recombination of the probe beams optically amplifies the Faraday Rotation (FR) signal. There are two benefits to this approach; traditional samples can be probed at lower intensities while maintaining signal quality, and weak FR signals, such as those found in the spintronic studies of quantum dot materials, can be optically amplified before detection. Vibrational isolation and thermal stability are important operational factors since the optical gain can be affected by optical path length difference between the two arms of the interferometer.

Laforge, J. M.; Steeves, G. M.

2006-03-01

4

Real-Time Systems.  

National Technical Information Service (NTIS)

This paper presents an introduction to the basic issues involved in real-time systems. Both real-time operating sys and real-time programming languages are explored. Concurrent programming and process synchronization and communication are also discussed. ...

S. M. Badr R. B. Byrnes D. P. Brutzman M. L. Nelson

1992-01-01

5

Real-time radiography  

SciTech Connect

Real-time radiography is used for imaging both dynamic events and static objects. Fluorescent screens play an important role in converting radiation to light, which is then observed directly or intensified and detected. The radiographic parameters for real-time radiography are similar to conventional film radiography with special emphasis on statistics and magnification. Direct-viewing fluoroscopy uses the human eye as a detector of fluorescent screen light or the light from an intensifier. Remote-viewing systems replace the human observer with a television camera. The remote-viewing systems have many advantages over the direct-viewing conditions such as safety, image enhancement, and the capability to produce permanent records. This report reviews real-time imaging system parameters and components.

Bossi, R.H.; Oien, C.T.

1981-02-26

6

Real-Time FRP  

Microsoft Academic Search

Functional reactive programming (FRP) is a declarative programming paradigm where the basic notions are continuous, time-varying behaviors and discrete, event-based reactivity. FRP has been used successfully in many reactive programming domains such as animation, robotics, and graphical user interfaces. The success of FRP in these domains encourages us to consider its use in real-time applications, where it is crucial that

Zhanyong Wan; Walid Taha; Paul Hudak

2001-01-01

7

Real-time cosmology  

NASA Astrophysics Data System (ADS)

In recent years, improved astrometric and spectroscopic techniques have opened the possibility of measuring the temporal change of radial and transverse position of sources in the sky over relatively short time intervals. This has made at least conceivable to establish a novel research domain, which we dub “real-time cosmology”. We review for the first time most of the work already done in this field, analysing the theoretical framework as well as some foreseeable observational strategies and their capability to constrain models. We first focus on real-time measurements of the overall redshift drift and angular separation shift in distant sources, which allows the observer to trace the background cosmic expansion and large scale anisotropy, respectively. We then examine the possibility of employing the same kind of observations to probe peculiar and proper accelerations in clustered systems, and therefore their gravitational potential. The last two sections are devoted to the future change of the cosmic microwave background on “short” time scales, as well as to the temporal shift of the temperature anisotropy power spectrum and maps. We conclude revisiting in this context the usefulness of upcoming experiments (like CODEX and Gaia) for real-time observations.

Quercellini, Claudia; Amendola, Luca; Balbi, Amedeo; Cabella, Paolo; Quartin, Miguel

2012-12-01

8

Real-Time PCR  

NASA Astrophysics Data System (ADS)

Over the past few years there has been a considerable development of DNA amplification by polymerase chain reaction (PCR), and real-time PCR has now superseded conventional PCR techniques in many areas, e.g., the quantification of nucleic acids and genotyping. This new approach is based on the detection and quantification of a fluorescent signal proportional to the amount of amplicons generated by PCR. Real-time detection is achieved by coupling a thermocycler with a fluorimeter. This chapter discusses the general principles of quantitative real-time PCR, the different steps involved in implementing the technique, and some examples of applications in medicine. The polymerase chain reaction (PCR) provides a way of obtaining a large number of copies of a double-stranded DNA fragment of known sequence. This DNA amplification technique, developed in 1985 by K. Mullis (Cetus Corporation), saw a spectacular development over the space of a few years, revolutionising the methods used up to then in molecular biology. Indeed, PCR has many applications, such as the detection of small amounts of DNA, cloning, and quantitative analysis (assaying), each of which will be discussed further below.

Evrard, A.; Boulle, N.; Lutfalla, G. S.

9

Real time SAR processing  

NASA Technical Reports Server (NTRS)

A simplified model for the SAR imaging problem is presented. The model is based on the geometry of the SAR system. Using this model an expression for the entire phase history of the received SAR signal is formulated. From the phase history, it is shown that the range and the azimuth coordinates for a point target image can be obtained by processing the phase information during the intrapulse and interpulse periods respectively. An architecture for a VLSI implementation for the SAR signal processor is presented which generates images in real time. The architecture uses a small number of chips, a new correlation processor, and an efficient azimuth correlation process.

Premkumar, A. B.; Purviance, J. E.

1990-01-01

10

A Real-Time Linux  

Microsoft Academic Search

The paper describes the design, implementation, experimental results, and possible applications of a real-time version of the Linux operating system. We have used the idea of virtual machines for running a standard time-sharing OS and a real-time executive on the same computer. Services provided by the real-time kernel are described. The comparison of our solution with other work on real-time

Victor Yodaiken; Michael Barabanov

1997-01-01

11

A Real-Time Linux  

Microsoft Academic Search

The paper describes the design, implementation, experimental results, and possible applications of a real-time version of the Linux operating system. We have used the idea of virtual machines for running a standard time-sharing OS and a real-time executive on the same computer. Services provided by the real-time kernel are described. The comparison of our solution with other work on real-time

M. Barabanov; V. Yodaiken

1996-01-01

12

Real time automated inspection  

DOEpatents

A method and apparatus relating to the real time automatic detection and classification of characteristic type surface imperfections occurring on the surfaces of material of interest such as moving hot metal slabs produced by a continuous steel caster. A data camera transversely scans continuous lines of such a surface to sense light intensities of scanned pixels and generates corresponding voltage values. The voltage values are converted to corresponding digital values to form a digital image of the surface which is subsequently processed to form an edge-enhanced image having scan lines characterized by intervals corresponding to the edges of the image. The edge-enhanced image is thresholded to segment out the edges and objects formed by the edges are segmented out by interval matching and bin tracking. Features of the objects are derived and such features are utilized to classify the objects into characteristic type surface imperfections.

Fant, Karl M. (Minneapolis, MN); Fundakowski, Richard A. (Saint Paul, MN); Levitt, Tod S. (Minneapolis, MN); Overland, John E. (Plymouth, MN); Suresh, Bindinganavle R. (New Brighton, MN); Ulrich, Franz W. (Minneapolis, MN)

1985-01-01

13

Real time automated inspection  

DOEpatents

A method and apparatus are described relating to the real time automatic detection and classification of characteristic type surface imperfections occurring on the surfaces of material of interest such as moving hot metal slabs produced by a continuous steel caster. A data camera transversely scans continuous lines of such a surface to sense light intensities of scanned pixels and generates corresponding voltage values. The voltage values are converted to corresponding digital values to form a digital image of the surface which is subsequently processed to form an edge-enhanced image having scan lines characterized by intervals corresponding to the edges of the image. The edge-enhanced image is thresholded to segment out the edges and objects formed by the edges by interval matching and bin tracking. Features of the objects are derived and such features are utilized to classify the objects into characteristic type surface imperfections. 43 figs.

Fant, K.M.; Fundakowski, R.A.; Levitt, T.S.; Overland, J.E.; Suresh, B.R.; Ulrich, F.W.

1985-05-21

14

Real time polarimetric dehazing.  

PubMed

Remote sensing is a rich topic due to its utility in gathering detailed accurate information from locations that are not economically feasible traveling destinations or are physically inaccessible. However, poor visibility over long path lengths is problematic for a variety of reasons. Haze induced by light scatter is one cause for poor visibility and is the focus of this article. Image haze comes about as a result of light scattering off particles and into the imaging path causing a haziness to appear on the image. Image processing using polarimetric information of light scatter can be used to mitigate image haze. An imaging polarimeter which provides the Stokes values in real time combined with a "dehazing" algorithm can automate image haze removal for instant applications. Example uses are to improve visual display providing on-the-spot detection or imbedding in an active control loop to improve viewing and tracking while on a moving platform. In addition, removing haze in this manner allows the trade space for a system operational waveband to be opened up to bands which are object matched and not necessarily restricted by scatter effects. PMID:23518739

Mudge, Jason; Virgen, Miguel

2013-03-20

15

Real-time visual servoing  

Microsoft Academic Search

A real-time tracking algorithm in conjunction with a predictive filter to allow real-time visual servoing of a robotic arm that is tracking a moving object is described. The system consists of two calibrated (but unregistered) cameras that provide images to a real-time, pipeline-parallel optic-flow algorithm that can robustly compute optic-flow and calculate the 3-D position of a moving object at

Peter K. Allen; Billibon Yoshimi; Aleksandar Timcenko

1991-01-01

16

Real-Time Simulation Clock.  

National Technical Information Service (NTIS)

A real time simulation clock is decribed for generating frame tics that synchronize computations to the real time and to other computations in a system that has a central computer and multiple remote sites that utilize the central computer. Timing tics ar...

D. R. Bennington D. J. Crawford

1987-01-01

17

Faraday's Cage  

NSDL National Science Digital Library

This video from MIT demonstrates the effect of a Faraday cage in an electric field. A Benjamin Franklin figure is first shown exposed to the electric field before he is covered with a metal cage and protected from the field.

2009-07-08

18

Towards Real Time Volume Rendering  

Microsoft Academic Search

The task of real time rendering of today's volumetric datasets is still being tackled by several research groups. A quick calculation of the amount of computation required for real-time rendering of a high resolution volume puts us in the teraflop range. Yet, the demand to support such rendering capabilities is increasing due to emerging technologies such as virtual surgery simulation

Roni Yagel

1996-01-01

19

Michael Faraday vs. the Spiritualists  

NASA Astrophysics Data System (ADS)

In the 1850s, renowned physicist Michael Faraday launched a public campaign against pseudoscience and spiritualism, which were rampant in England at the time. Faraday objected especially to claims that electrical or magnetic forces were responsible for paranormal phenomena, such as table-spinning and communication with the dead. Using scientific methods, Faraday unmasked the deceptions of spiritualists, clairvoyants and mediums and also laid bare the credulity of a public ill-educated in science. Despite his efforts, Victorian society's fascination with the paranormal swelled. Faraday's debacle anticipates current controversies about public science education and the interface between science and religion. This episode is one of many described in the new biography, The Electric Life of Michael Faraday (Walker & Co.), which chronicles Faraday's discoveries and his unlikely rise from poverty to the pinnacle of the English science establishment.

Hirshfeld, Alan

2006-12-01

20

Real-time virtual humans  

Microsoft Academic Search

The last few years have seen great maturation in the com- putation speed and control methods needed to portray 3D virtual humans suitable for real interactive applications. We first describe the state of the art, then focus on the particular approach taken at the University of Pennsylvania with the Jack system. Various aspects of real-time virtual humans are considered, such

Norman I. Badler

1997-01-01

21

Real-time flutter identification  

NASA Technical Reports Server (NTRS)

The techniques and a FORTRAN 77 MOdal Parameter IDentification (MOPID) computer program developed for identification of the frequencies and damping ratios of multiple flutter modes in real time are documented. Physically meaningful model parameterization was combined with state of the art recursive identification techniques and applied to the problem of real time flutter mode monitoring. The performance of the algorithm in terms of convergence speed and parameter estimation error is demonstrated for several simulated data cases, and the results of actual flight data analysis from two different vehicles are presented. It is indicated that the algorithm is capable of real time monitoring of aircraft flutter characteristics with a high degree of reliability.

Roy, R.; Walker, R.

1985-01-01

22

Real-time software receiver  

NASA Technical Reports Server (NTRS)

A real-time software receiver that executes on a general purpose processor. The software receiver includes data acquisition and correlator modules that perform, in place of hardware correlation, baseband mixing and PRN code correlation using bit-wise parallelism.

Ledvina, Brent M. (Inventor); Psiaki, Mark L. (Inventor); Powell, Steven P. (Inventor); Kintner, Jr., Paul M. (Inventor)

2007-01-01

23

Real-time software receiver  

NASA Technical Reports Server (NTRS)

A real-time software receiver that executes on a general purpose processor. The software receiver includes data acquisition and correlator modules that perform, in place of hardware correlation, baseband mixing and PRN code correlation using bit-wise parallelism.

Ledvina, Brent M. (Inventor); Psiaki, Mark L. (Inventor); Powell, Steven P. (Inventor); Kintner, Jr., Paul M. (Inventor)

2006-01-01

24

Composing Real-Time Systems  

Microsoft Academic Search

We present a method to construct real-time systems using as components anytime algo- rithms whose quality of results degrades grace­ fully as computation time decreases. Introduc­ ing computation time as a degree of freedom defines a scheduling problem involving the ac­ tivation and interruption of the anytime com­ ponents. This scheduling problem is especially complicated when trying to construct inter-

Stuart J. Russell; Shlomo Zilberstein

1991-01-01

25

Real-Time Complex Systems.  

National Technical Information Service (NTIS)

We developed modified linear hybrid automata models for complex real- time tasks, e.g. tasks that have complex internal behaviors, may interact or synchronize in complex ways, and may have variable or not-fully-known timing characteristics. We report on i...

S. Vestal

2004-01-01

26

Reconciling Real-Time and 'Fair' Scheduling,  

National Technical Information Service (NTIS)

Multiprogramming operating systems which support both real-time and non-real-time processes are called soft-real-time systems. In such systems, process scheduling is problematic, because there are two qualitatively different classes of processes requiring...

B. O. Gallmeister

1988-01-01

27

Clinical virology in real time  

Microsoft Academic Search

The ability to detect nucleic acids has had and still has a major impact on diagnostics in clinical virology. Both quantitative and qualitative techniques, whether signal or target amplification based systems, are currently used routinely in most if not all virology laboratories. Technological improvements, from automated sample isolation to real time amplification technology, have given the ability to develop and

Hubert G. M Niesters

2002-01-01

28

Real Time Sonic Boom Display  

NASA Technical Reports Server (NTRS)

This presentation will provide general information about sonic boom mitigation technology to the public in order to supply information to potential partners and licensees. The technology is a combination of flight data, atmospheric data and terrain information implemented into a control room real time display for flight planning. This research is currently being performed and as such, any results and conclusions are ongoing.

Haering, Ed

2014-01-01

29

Real-time nonphotorealistic rendering  

Microsoft Academic Search

Nonphotorealistic rendering (NPR) can help make comprehensible but simple pictures of complicated objects by employing an econ- omy of line. But current nonphotorealistic rendering is primarily a batch process. This paper presents a real-time nonphotorealistic renderer that deliberately trades accuracy and detail for speed. Our renderer uses a method for determining visible lines and surfaces which is a modification of

Lee Markosian; Michael A. Kowalski; Daniel Goldstein; Samuel J. Trychin; John F. Hughes; Lubomir D. Bourdev

1997-01-01

30

Real Time Road Signs Recognition  

Microsoft Academic Search

This paper presents a road signs detection and classification system based on a three-step algorithm composed of color segmentation, shape recognition, and a neural network. The final goal of this algorithm is to detect and classify almost all road signs present along Italian roads. Color segmentation was suggested by the aim to achieve real time execution, since color-based segmentation is

Alberto Broggi; Pietro Cerri; Paolo Medici; Pier Paolo Porta; Guido Ghisio

2007-01-01

31

Real Time Weld Quality Monitor.  

National Technical Information Service (NTIS)

This citation summarizes a one-page announcement of technology available for utilization. A weld monitor with real time output can aid an inspector in designating suspect areas for nondestructive testing after welding. It also can be used to interrupt wel...

1982-01-01

32

Real-Time Fault Diagnostics  

Microsoft Academic Search

The intelligent process control system (IPCS), an integrated environment for developing complex process control and automation systems is discussed, focusing on its real-time fault diagnostics capability. IPCS has been used to build a supervisory monitoring and diagnostics system for a cogenerator plant. The requirements and problems specific to such systems are examined. The key concepts involved in fault modeling in

Samir Padalkar; Gabor Karsai; Csaba Biegl; Janos Sztipanovits; Koji Okuda; Nobuji Miyasaka

1991-01-01

33

Real-time regional forecasting  

Microsoft Academic Search

An observational network, dynamical models and data assimilation schemes are the three components of an ocean prediction system. Its configuration for a regional real-time forecasting system proceeds in three phases, based on previous knowledge and experience of the area. In the initial (exploratory) phase, identification of dominant scales (synoptic, mesoscale and submesoscale), processes and interactions is obtained. In the intermediate

Allan R. Robinson; Hernan G. Arango; Alex Warn-Varnas; Wayne G. Leslie; Arthur J. Miller; Patrick J. Haley; Carlos J. Lozano

1996-01-01

34

[Real time 3D echocardiography  

NASA Technical Reports Server (NTRS)

Three-dimensional representation of the heart is an old concern. Usually, 3D reconstruction of the cardiac mass is made by successive acquisition of 2D sections, the spatial localisation and orientation of which require complex guiding systems. More recently, the concept of volumetric acquisition has been introduced. A matricial emitter-receiver probe complex with parallel data processing provides instantaneous of a pyramidal 64 degrees x 64 degrees volume. The image is restituted in real time and is composed of 3 planes (planes B and C) which can be displaced in all spatial directions at any time during acquisition. The flexibility of this system of acquisition allows volume and mass measurement with greater accuracy and reproducibility, limiting inter-observer variability. Free navigation of the planes of investigation allows reconstruction for qualitative and quantitative analysis of valvular heart disease and other pathologies. Although real time 3D echocardiography is ready for clinical usage, some improvements are still necessary to improve its conviviality. Then real time 3D echocardiography could be the essential tool for understanding, diagnosis and management of patients.

Bauer, F.; Shiota, T.; Thomas, J. D.

2001-01-01

35

Interactive real time flow simulations  

NASA Technical Reports Server (NTRS)

An interactive real time flow simulation technique is developed for an unsteady channel flow. A finite-volume algorithm in conjunction with a Runge-Kutta time stepping scheme was developed for two-dimensional Euler equations. A global time step was used to accelerate convergence of steady-state calculations. A raster image generation routine was developed for high speed image transmission which allows the user to have direct interaction with the solution development. In addition to theory and results, the hardware and software requirements are discussed.

Sadrehaghighi, I.; Tiwari, S. N.

1990-01-01

36

Real-Time Weather Data  

NSDL National Science Digital Library

This website provides real-time and forecast weather maps and data for the United States. The Satellite section contains satellite weather images from the GOES 8 and GOES 10 satellites, the Radar section contains radar weather images from NEXRAD radars, the Surface Data section contains plots of various weather conditions (temperatures, winds, pressure, precipitation), and the Upper Air section plots winds and temperatures across the United States.

37

Real-Time Crying Simulation  

Microsoft Academic Search

Displaying facial motions such as crying or laughing is difficult to achieve in real-time simulations and games. Not only\\u000a because of the complicated simulation of the physical characteristics such as muscle motions or fluid simulations, but also\\u000a because one needs to know how to control these motions on a higher level. In this paper, we propose a method that uses

Wijnand Van Tol; Arjan Egges

2009-01-01

38

Real-time tritium imaging  

SciTech Connect

A real-time image of a tritium-containing titanium film has been made by detecting the secondary electrons produced by tritium ..beta.. decay with a simple two-element electrostatic lens and microchannel plate image intensifier. The obtained image indicates that a resolution of better than 100 ..mu..m is currently obtainable and suggests that image magnification to enhance resolution should be possible.

Malinowski, M.E.

1981-09-15

39

Real-time flutter analysis  

NASA Technical Reports Server (NTRS)

The important algorithm issues necessary to achieve a real time flutter monitoring system; namely, the guidelines for choosing appropriate model forms, reduction of the parameter convergence transient, handling multiple modes, the effect of over parameterization, and estimate accuracy predictions, both online and for experiment design are addressed. An approach for efficiently computing continuous-time flutter parameter Cramer-Rao estimate error bounds were developed. This enables a convincing comparison of theoretical and simulation results, as well as offline studies in preparation for a flight test. Theoretical predictions, simulation and flight test results from the NASA Drones for Aerodynamic and Structural Test (DAST) Program are compared.

Walker, R.; Gupta, N.

1984-01-01

40

Abstraction Planning in Real Time  

NASA Technical Reports Server (NTRS)

When a planning agent works in a complex, real-world domain, it is unable to plan for and store all possible contingencies and problem situations ahead of time. This thesis presents a method for planning a run time that incrementally builds up plans at multiple levels of abstraction. The plans are continually updated by information from the world, allowing the planner to adjust its plan to a changing world during the planning process. All the information is represented over intervals of time, allowing the planner to reason about durations, deadlines, and delays within its plan. In addition to the method, the thesis presents a formal model of the planning process and uses the model to investigate planning strategies.

Washington, R.

1994-01-01

41

The Real Time Ocean Environment  

NSDL National Science Digital Library

This site from the Naval Research Laboratory Stennis Space Center features a real time look at the world's oceans as remotely sensed from earth orbiting satellites. Data can be accessed for different regions of the earth and include altimetry, temperature and salinity, and derived sea surface products. Each plot has a title at the top indicating three things: the region represented, the altimeter from which the data was obtained, and the type of data plotted. More information about the plots can be found in data sources. Detailed information about the data types can be gained from the other headings in the table of contents of the page.

Whitmer, Kirk; Naval Research Laboratory Stennis Space Center, Ms

42

Real-time analysis keratometer  

NASA Technical Reports Server (NTRS)

A computer assisted keratometer in which a fiducial line pattern reticle illuminated by CW or pulsed laser light is projected on a corneal surface through lenses, a prismoidal beamsplitter quarterwave plate, and objective optics. The reticle surface is curved as a conjugate of an ideal corneal curvature. The fiducial image reflected from the cornea undergoes a polarization shift through the quarterwave plate and beamsplitter whereby the projected and reflected beams are separated and directed orthogonally. The reflected beam fiducial pattern forms a moire pattern with a replica of the first recticle. This moire pattern contains transverse aberration due to differences in curvature between the cornea and the ideal corneal curvature. The moire pattern is analyzed in real time by computer which displays either the CW moire pattern or a pulsed mode analysis of the transverse aberration of the cornea under observation, in real time. With the eye focused on a plurality of fixation points in succession, a survey of the entire corneal topography is made and a contour map or three dimensional plot of the cornea can be made as a computer readout in addition to corneal radius and refractive power analysis.

Adachi, Iwao P. (Inventor); Adachi, Yoshifumi (Inventor); Frazer, Robert E. (Inventor)

1987-01-01

43

Real-time flood forecasting  

USGS Publications Warehouse

Researchers at the Hydroinformatic Research and Development Team (HIRDT) of the National Taiwan University undertook a project to create a real time flood forecasting model, with an aim to predict the current in the Tamsui River Basin. The model was designed based on deterministic approach with mathematic modeling of complex phenomenon, and specific parameter values operated to produce a discrete result. The project also devised a rainfall-stage model that relates the rate of rainfall upland directly to the change of the state of river, and is further related to another typhoon-rainfall model. The geographic information system (GIS) data, based on precise contour model of the terrain, estimate the regions that were perilous to flooding. The HIRDT, in response to the project's progress, also devoted their application of a deterministic model to unsteady flow of thermodynamics to help predict river authorities issue timely warnings and take other emergency measures.

Lai, C.; Tsay, T. -K.; Chien, C. -H.; Wu, I. -L.

2009-01-01

44

Deconvolving Current from Faraday Rotation Measurement  

SciTech Connect

In this paper, a unique software program is reported which automatically decodes the Faraday rotation signal into a time-dependent current representation. System parameters, such as the Faraday fiber’s Verdet constant and number of loops in the sensor, are the only user-interface inputs. The central aspect of the algorithm utilizes a short-time Fourier transform, which reveals much of the Faraday rotation measurement’s implicit information necessary for unfolding the dynamic current measurement.

Stephen E. Mitchell

2008-02-01

45

Autonomous Real Time Requirements Tracing  

NASA Technical Reports Server (NTRS)

One of the more challenging aspects of software development is the ability to verify and validate the functional software requirements dictated by the Software Requirements Specification (SRS) and the Software Detail Design (SDD). Insuring the software has achieved the intended requirements is the responsibility of the Software Quality team and the Software Test team. The utilization of Timeliner-TLX(sup TM) Auto-Procedures for relocating ground operations positions to ISS automated on-board operations has begun the transition that would be required for manned deep space missions with minimal crew requirements. This transition also moves the auto-procedures from the procedure realm into the flight software arena and as such the operational requirements and testing will be more structured and rigorous. The autoprocedures would be required to meet NASA software standards as specified in the Software Safety Standard (NASASTD- 8719), the Software Engineering Requirements (NPR 7150), the Software Assurance Standard (NASA-STD-8739) and also the Human Rating Requirements (NPR-8705). The Autonomous Fluid Transfer System (AFTS) test-bed utilizes the Timeliner-TLX(sup TM) Language for development of autonomous command and control software. The Timeliner- TLX(sup TM) system has the unique feature of providing the current line of the statement in execution during real-time execution of the software. The feature of execution line number internal reporting unlocks the capability of monitoring the execution autonomously by use of a companion Timeliner-TLX(sup TM) sequence as the line number reporting is embedded inside the Timeliner-TLX(sup TM) execution engine. This negates I/O processing of this type data as the line number status of executing sequences is built-in as a function reference. This paper will outline the design and capabilities of the AFTS Autonomous Requirements Tracker, which traces and logs SRS requirements as they are being met during real-time execution of the targeted system. It is envisioned that real time requirements tracing will greatly assist the movement of autoprocedures to flight software enhancing the software assurance of auto-procedures and also their acceptance as reliable commanders

Plattsmier, George I.; Stetson, Howard K.

2014-01-01

46

Autonomous Real Time Requirements Tracing  

NASA Technical Reports Server (NTRS)

One of the more challenging aspects of software development is the ability to verify and validate the functional software requirements dictated by the Software Requirements Specification (SRS) and the Software Detail Design (SDD). Insuring the software has achieved the intended requirements is the responsibility of the Software Quality team and the Software Test team. The utilization of Timeliner-TLX(sup TM) Auto- Procedures for relocating ground operations positions to ISS automated on-board operations has begun the transition that would be required for manned deep space missions with minimal crew requirements. This transition also moves the auto-procedures from the procedure realm into the flight software arena and as such the operational requirements and testing will be more structured and rigorous. The autoprocedures would be required to meet NASA software standards as specified in the Software Safety Standard (NASASTD- 8719), the Software Engineering Requirements (NPR 7150), the Software Assurance Standard (NASA-STD-8739) and also the Human Rating Requirements (NPR-8705). The Autonomous Fluid Transfer System (AFTS) test-bed utilizes the Timeliner-TLX(sup TM) Language for development of autonomous command and control software. The Timeliner-TLX(sup TM) system has the unique feature of providing the current line of the statement in execution during real-time execution of the software. The feature of execution line number internal reporting unlocks the capability of monitoring the execution autonomously by use of a companion Timeliner-TLX(sup TM) sequence as the line number reporting is embedded inside the Timeliner-TLX(sup TM) execution engine. This negates I/O processing of this type data as the line number status of executing sequences is built-in as a function reference. This paper will outline the design and capabilities of the AFTS Autonomous Requirements Tracker, which traces and logs SRS requirements as they are being met during real-time execution of the targeted system. It is envisioned that real time requirements tracing will greatly assist the movement of autoprocedures to flight software enhancing the software assurance of auto-procedures and also their acceptance as reliable commanders.

Plattsmier, George; Stetson, Howard

2014-01-01

47

Real-Time Signal Processing Systems.  

National Technical Information Service (NTIS)

Develop Expandable Vector Accelerator (EVA) and its hardware and software capable of processing range and range rate data, digital focus, real-time Kalman filtering, real-time target motion resolution (TMR), and processing image/pattern information for re...

M. Andrews

1992-01-01

48

Real-Time Systems - Biologically Inspired Future  

Microsoft Academic Search

In this paper, we are presenting a bionic approach towards real-time systems research. Observing that a cell is both real-time computing and real-time manufacturing system, the work presented here explores the analogy between the real-time computer systems (and their management) and the molecular biology control systems. This paper is a further elaboration of the idea that the cell is governed

Nevena Ackovska; Stevo Bozinovski; Gjorgji Jovancevski

2008-01-01

49

Real Time Scheduling Theory: A Historical Perspective  

Microsoft Academic Search

In this 25th year anniversary paper for the IEEE Real Time Systems Symposium, we review the key results in real time scheduling theory and the his- torical events that led to the establishment of the current real time computing infrastructure. We conclude this paper by looking at the challenges ahead of us.

Lui Sha; Tarek F. Abdelzaher; Karl-erik Årzén; Anton Cervin; Theodore P. Baker; Alan Burns; Giorgio C. Buttazzo; Marco Caccamo; John P. Lehoczky; Aloysius K. Mok

2004-01-01

50

Real-time metabolic imaging  

NASA Astrophysics Data System (ADS)

The endogenous substance pyruvate is of major importance to maintain energy homeostasis in the cells and provides a window to several important metabolic processes essential to cell survival. Cell viability is therefore reflected in the metabolism of pyruvate. NMR spectroscopy has until now been the only noninvasive method to gain insight into the fate of pyruvate in the body, but the low NMR sensitivity even at high field strength has only allowed information about steady-state conditions. The medically relevant information about the distribution, localization, and metabolic rate of the substance during the first minute after the injection has not been obtainable. Use of a hyperpolarization technique has enabled 10-15% polarization of 13C1 in up to a 0.3 M pyruvate solution. i.v. injection of the solution into rats and pigs allows imaging of the distribution of pyruvate and mapping of its major metabolites lactate and alanine within a time frame of 10 s. Real-time molecular imaging with MRI has become a reality. 13C | dynamic nuclear polarization | hyperpolarized | MRI | spectroscopy

Golman, Klaes; in 't Zandt, René; Thaning, Mikkel

2006-07-01

51

Real-Time Data Display  

NASA Technical Reports Server (NTRS)

RT-Display is a MATLAB-based data acquisition environment designed to use a variety of commercial off-the-shelf (COTS) hardware to digitize analog signals to a standard data format usable by other post-acquisition data analysis tools. This software presents the acquired data in real time using a variety of signal-processing algorithms. The acquired data is stored in a standard Operator Interactive Signal Processing Software (OISPS) data-formatted file. RT-Display is primarily configured to use the Agilent VXI (or equivalent) data acquisition boards used in such systems as MIDDAS (Multi-channel Integrated Dynamic Data Acquisition System). The software is generalized and deployable in almost any testing environment, without limitations or proprietary configuration for a specific test program or project. With the Agilent hardware configured and in place, users can start the program and, in one step, immediately begin digitizing multiple channels of data. Once the acquisition is completed, data is converted into a common binary format that also can be translated to specific formats used by external analysis software, such as OISPS and PC-Signal (product of AI Signal Research Inc.). RT-Display at the time of this reporting was certified on Agilent hardware capable of acquisition up to 196,608 samples per second. Data signals are presented to the user on-screen simultaneously for 16 channels. Each channel can be viewed individually, with a maximum capability of 160 signal channels (depending on hardware configuration). Current signal presentations include: time data, fast Fourier transforms (FFT), and power spectral density plots (PSD). Additional processing algorithms can be easily incorporated into this environment.

Pedings, Marc

2007-01-01

52

Faraday effect current sensing using a Sagnac interferometer with a 3 (times) 3 coupler  

SciTech Connect

We demonstrate a fiber optic current sensor based on a Sagnac interferometer with a 3 {times} 3 coupler. Compared to the more common Sagnac interferometer with a 2 {times} 2 coupler, this design offers the additional benefits of a greater response for small signals and the unambiguous interpretation of signals that exceed the period of the response function. 6 refs., 6 figs.

Veeser, L.R. (Los Alamos National Lab., NM (USA)); Day, G.W. (National Inst. of Standards and Technology, Boulder, CO (USA))

1990-01-01

53

Real-Time Communication in Multihop Networks  

Microsoft Academic Search

Communication in real-time systems has to be predictable, because unpredictable delaysin the delivery of messages can adversely affect the execution of tasks dependent onthese messages. We develop a scheme for providing predictable interprocesscommunication in real-time systems with (partially connected) point-to-pointinterconnection networks, which provide guarantees on the maximum delivery time formessages. This scheme is based on the concept of a real-time

Dilip D. Kandlur; Kang G. Shin; Domenico Ferrari

1994-01-01

54

The Real-Time Channel Administration Protocol  

Microsoft Academic Search

The Real-time Channel Administration Protocol (RCAP) provides con- trol and administration services for the Tenet real-time protocol suite, a connection-oriented suite of network and transport layer protocols for real- time communication. RCAP performs per-channel reservation of network resources based on worst-case analysis to provide hard guarantees on delay, jitter, and packet loss bounds. It uses a hierarchical approach to provide

Anindo Banerjea; Bruce A. Mah

1991-01-01

55

Composing Synchronization and Real-Time Constraints  

Microsoft Academic Search

There have been a number of publications illustrating the su ccesses of object-oriented techniques in creating highly reusable software systems. Several concurrent languages have been proposed for specifying reusable synchronization specifications. Recently, a number of real-time object-oriented languages have been introduced for building object-oriented programs with real-time behavior. Composing and reusing object-oriented programs with both synchronization and real-time constraints has

Lodewijk Bergmans; Mehmet Aksit

1996-01-01

56

Evolvable real-time C3 systems  

Microsoft Academic Search

This paper describes MITRE's Evolvable Real-Time Command, Control, and Communications (C3) systems initiative that attempts to develop an approach that would enable current real-time systems to evolve into the systems of the future. In particular, this article describes the infrastructure requirements that we have developed. We first provide an overview of the current real-time C3 systems and describe the systems

Edward H. Bensley; Lawrence Fisher; Mike Gates; James Houchens; Arkady Kanevsky; Soohee Kim; Peter C. Krupp; Alice Schafer; Bhavani M. Thuraisingham

1995-01-01

57

Issues in Real-Time Data Management  

Microsoft Academic Search

Abstract: This report explores issues related to the use of database management technology in support of real-time system programming.,It describes the potential benefits of database support for real-time systems, and it describes the state of the art in database ,technologies relevant to real-time. The report concludes ,that more,research and development ,will be needed ,before the benefits of database management,can be

Marc H. Graham

1992-01-01

58

MARTe: A Multiplatform Real-Time Framework  

Microsoft Academic Search

Development of real-time applications is usually associated with nonportable code targeted at specific real-time operating systems. The boundary between hardware drivers, system services, and user code is commonly not well defined, making the development in the target host significantly difficult. The Multithreaded Application Real-Time executor (MARTe) is a framework built over a multiplatform library that allows the execution of the

André C. Neto; Filippo Sartori; Fabio Piccolo; Riccardo Vitelli; Gianmaria De Tommasi; Luca Zabeo; Antonio Barbalace; Horacio Fernandes; Daniel F. Valcárcel; Antonio J. N. Batista

2010-01-01

59

Embedded Robust Control Real-Time Scheduling  

Microsoft Academic Search

The existing scheduling algorithms cannot adequately support modern embedded real-time applications. An important challenge for future research is how to model and introduce control mechanisms to real-time systems to improve real-time performance, and to allow the system to adapt to changes in the environment, the workload, or to changes in the system architecture due to failures. In this paper, we

Bing Du; Chun Ruan

2008-01-01

60

An interleaving model for real-time  

Microsoft Academic Search

Real-time is incorporated into the interleaving model, which is used for the practical specification and verification of many properties of concurrent systems, by defining the abstract notion of a real-time transition system as a conservative extension of traditional transition systems. Qualitative fairness requirements are replaced (and superseded) by quantitative lower-bound and upper-bound real-time requirements for transitions. Proof rules are presented

Thomas A. Henzinger; Zohar Manna; Amir Pnueli

1990-01-01

61

Research in Distributed Real-Time Systems  

NASA Technical Reports Server (NTRS)

This document summarizes the progress we have made on our study of issues concerning the schedulability of real-time systems. Our study has produced several results in the scalability issues of distributed real-time systems. In particular, we have used our techniques to resolve schedulability issues in distributed systems with end-to-end requirements. During the next year (1997-98), we propose to extend the current work to address the modeling and workload characterization issues in distributed real-time systems. In particular, we propose to investigate the effect of different workload models and component models on the design and the subsequent performance of distributed real-time systems.

Mukkamala, R.

1997-01-01

62

Energy efficient real-time scheduling  

Microsoft Academic Search

Real-time scheduling on processors that support dynamic voltage and frequency scaling is analyzed. The Slacked Earliest Deadling First (SEDF) algorithm is proposed and it is shown that the algorithm is optimal in minimizing processor energy consumption and maximum lateness. An upper bound on the processor energy savings is also derived. Real-time scheduling of periodic tasks is also analyzed and optimal

Amit Sinha; Anantha P. Chandrakasan

2001-01-01

63

Real-Time Fracture of Stiff Materials  

Microsoft Academic Search

This paper describes the implementation of system to model the dy- namic fracture of stiff materials in real-time for use in modern game environments. Based around a tetrahedral finite element system, we aim to model the effects of stress tensors over the body of an ob- ject, and to compute the disruptions to the object's surface structure in real time.

Owen McNally

64

Real-time communication protocols: an overview  

Microsoft Academic Search

This paper describes several existing data link layer protocols that provide real-time capabilities on wired networks, focusing on token-ring and Carrier Sense Multiple Access based networks. Existing modifications to provide better real-time capabilities and performance are also described. Finally the pros and cons regarding the At-Home Anywhere project are discussed.

Ferdy Hanssen; Pierre G. Jansen

2003-01-01

65

Real time programming environment for Windows  

SciTech Connect

This document provides a description of the Real Time Programming Environment (RTProE). RTProE tools allow a programmer to create soft real time projects under general, multi-purpose operating systems. The basic features necessary for real time applications are provided by RTProE, leaving the programmer free to concentrate efforts on his specific project. The current version supports Microsoft Windows{trademark} 95 and NT. The tasks of real time synchronization and communication with other programs are handled by RTProE. RTProE includes a generic method for connecting a graphical user interface (GUI) to allow real time control and interaction with the programmer`s product. Topics covered in this paper include real time performance issues, portability, details of shared memory management, code scheduling, application control, Operating System specific concerns and the use of Computer Aided Software Engineering (CASE) tools. The development of RTProE is an important step in the expansion of the real time programming community. The financial costs associated with using the system are minimal. All source code for RTProE has been made publicly available. Any person with access to a personal computer, Windows 95 or NT, and C or FORTRAN compilers can quickly enter the world of real time modeling and simulation.

LaBelle, D.R. [LaBelle (Dennis R.), Clifton Park, NY (United States)

1998-04-01

66

High-throughput real-time PCR.  

PubMed

Real-time PCR is presently the gold standard of gene expression quantification. Configuration of real-time PCR instruments with 384-well reaction blocks, enables the instrument to be used essentially as a low-density array. While PCR will never rival the throughput of microchip arrays, in situations where one is interested in assaying several hundreds of genes, high throughput, real-time PCR is an excellent alternative to microchip arrays. By combining SYBR green detection and 5 microL reaction volume, the associated costs of high-throughput real-time PCR are comparable to microarrays. Described here is a complete protocol to perform real-time PCR in a 384-well configuration. Examples are provided to access numerous PCR primer sequences that may be used for high-throughput real-time PCR. Methods of analysis are described to present real-time PCR data as heat maps and clustered similar to the presentation of cDNA microarray data. An example is provided to profile the expression of over 200 microRNA precursors using high-throughput real-time PCR. PMID:18695961

Schmittgen, Thomas D; Lee, Eun Joo; Jiang, Jinmai

2008-01-01

67

Real Time Distributed Control Systems Using RTAI  

Microsoft Academic Search

The paper outlines the design and implementation of the Real Time Application Interface (RTAI) for Linux, as used for high performance local\\/distributed control systems implemented on low cost off the shelf general purpose computers. Its native lean real time middleware layer is described along with its use in an advanced tool to easily manage and monitor complex networked control systems.

Lorenzo Dozio; Paolo Mantegazza

2003-01-01

68

Real-time video quality assessment platform  

Microsoft Academic Search

This paper presents a system for real-time video quality monitoring up to full-HD resolution in a networked environment. As sources of quality degradations, artifacts coming from block based compression are considered. The developed system captures live video, extracts video quality indicators in real-time, and renders them on the remote workstation.

Istvan PAPP; N. Lukic; Z. Marceta; N. Teslic; M. Schu

2009-01-01

69

Real-Time Enhancements for Embedded Linux  

Microsoft Academic Search

With the popularity of using Linux for embedded systems, its real-time performance is increasingly becoming an importance issue for applications that require short latency and task execution predictability as commonly encountered in many embedded systems. This paper presents a survey of the approaches used by commercial vendors and open source community to enhance the real-time performance of the Linux kernel.

N. Vun; H. F. Hor; J. W. Chao

2008-01-01

70

Real-time DNA microarrays: reality check  

PubMed Central

DNA microarrays are plagued with inconsistent quantifications and false-positive results. Using established mechanisms of surface reactions, we argue that these problems are inherent to the current technology. In particular, the problem of multiplex non-equilibrium reactions cannot be resolved within the framework of the existing paradigm. We discuss the advantages and limitations of changing the paradigm to real-time data acquisition similar to real-time PCR methodology. Our analysis suggests that the fundamental problem of multiplex reactions is not resolved by the real-time approach itself. However, by introducing new detection chemistries and analysis approaches, it is possible to extract target-specific quantitative information from real-time microarray data. The possible scope of applications for real-time microarrays is discussed.

Chagovetz, Alexander; Blair, Steve

2010-01-01

71

Two-Frequency Paired Polarization Interferometer for Faraday Rotation Angle Detection  

NASA Astrophysics Data System (ADS)

A highly sensitive two-frequency paired linear polarized interferometer (TPPI) for measuring the Faraday rotation angle and Verdet constant of the Bi12SiO20 (BSO) crystal in real time was set up by an amplitude-sensitive detection method. TPPI features a common-path heterodyne interferometer in conjunction with a highly correlated paired linear polarized laser beam. Then, the antisymmetry of polarized heterodyne signals is produced and Faraday rotation angle detection by a balanced detector scheme is satisfied automatically. As a result, shot-noise-limited detection of Faraday rotation angle is possible. In addition, the Faraday rotation angle detection is also insensitive to the scattering and absorption caused by the specimen because of the common-path propagation of the paired linear polarized laser beam. Experimentally, the sensitivities of Faraday rotation angle and Verdet constant measurements of the BSO crystal under the arrangement with a single pass of the laser beam in TPPI are 4.93× 10-5 rad/mm and 2.6× 10-7 rad/(mT\\cdotmm), respectively. This suggests that the Faraday rotation angle detection sensitivity has the potential to be on the order of 10-8 rad/mm if a Fabry-Perot cavity with a finesse of F=120 is used in TPPI.

Lin, Chu-En; Chang, Jin-Gor; Chou, Li-Dek; Yu, Chih-Jen; Lee, Cheng-Chung; Chou, Chien

2009-08-01

72

TRACE CHECKING WITH REAL-TIME SPECIFICATIONS  

Microsoft Academic Search

Obtaining full models for the validation and verification of embedded systems is often diffi- cult. The presented approach overcomes this problem by checking finite traces, which does not require any system model. Traces are generated by test car runs or hardware-in-the-loop simulation. We pro- pose a canonical extension of linear-time temporal logic (LTL) for real-time specifications. Our algorithm translates real-time

Rocco Deutschmann; Matthias Fruth; Horst Reichel; Hans-Christian Reuss

73

Programming real-time applications with SIGNAL  

Microsoft Academic Search

The authors present the main features of the SIGNAL language and its compiler. Designed to provide safe real time system programming, the SIGNAL language is based on synchronous principles. Its semantics are defined via a mathematical model of multiple-clocked flows of data and events. SIGNAL programs describe relations on such objects, so that it is possible to program a real

P. LeGuernic; THIERRY GAUTIER; MICHEL LE BORGNE; CLAUDE LE MAIRE

1991-01-01

74

Real-Time Monitoring of Active Landslides  

USGS Publications Warehouse

Landslides threaten lives and property in every State in the Nation. To reduce the risk from active landslides, the U.S. Geological Survey (USGS) develops and uses real-time landslide monitoring systems. Monitoring can detect early indications of rapid, catastrophic movement. Up-to-the-minute or real-time monitoring provides immediate notification of landslide activity, potentially saving lives and property. Continuous information from real-time monitoring also provides a better understanding of landslide behavior, enabling engineers to create more effective designs for halting landslide movement.

Reid, Mark E.; LaHusen, Richard G.; Ellis, William L.

1999-01-01

75

Real-time monitoring of landslides  

USGS Publications Warehouse

Landslides cause fatalities and property damage throughout the Nation. To reduce the impact from hazardous landslides, the U.S. Geological Survey develops and uses real-time and near-real-time landslide monitoring systems. Monitoring can detect when hillslopes are primed for sliding and can provide early indications of rapid, catastrophic movement. Continuous information from up-to-the-minute or real-time monitoring provides prompt notification of landslide activity, advances our understanding of landslide behavior, and enables more effective engineering and planning efforts.

Reid, Mark E.; LaHusen, Richard G.; Baum, Rex L.; Kean, Jason W.; Schulz, William H.; Highland, Lynn M.

2012-01-01

76

Real time sensor for therapeutic radiation delivery  

DOEpatents

The invention is a real time sensor for therapeutic radiation. A probe is placed in or near the patient that senses in real time the dose at the location of the probe. The strength of the dose is determined by either an insertion or an exit probe. The location is determined by a series of vertical and horizontal sensing elements that gives the operator a real time read out dose location relative to placement of the patient. The increased accuracy prevents serious tissue damage to the patient by preventing overdose or delivery of a dose to a wrong location within the body. 14 figs.

Bliss, M.; Craig, R.A.; Reeder, P.L.

1998-01-06

77

Achieving real-time performance in FIESTA  

NASA Technical Reports Server (NTRS)

The Fault Isolation Expert System for TDRSS Applications (FIESTA) is targeted for operation in a real-time online environment. Initial stages of the prototype development concentrated on acquisition and representation of the knowledge necessary to isolate faults in the TDRSS Network. Recent efforts focused on achieving real-time performance including: a discussion of the meaning of FIESTA real-time requirements, determination of performance levels (benchmarking) and techniques for optimization. Optimization techniques presented include redesign of critical relations, filtering of redundant data and optimization of patterns used in rules. Results are summarized.

Wilkinson, William; Happell, Nadine; Miksell, Steve; Quillin, Robert; Carlisle, Candace

1988-01-01

78

An Efficient Real-Time Middleware Scheduling Algorithm for Periodic Real-Time Tasks  

Microsoft Academic Search

\\u000a For real-time applications, the underlying operating system (OS) should support timely management of real-time tasks. However,\\u000a most of current operating systems do not provide timely management facilities in an efficient way. There could be two approaches\\u000a to support timely management facilities for real-time applications: (1) by modifying OS kernel and (2) by providing a middleware\\u000a without modifying OS. In our

Ho-joon Park; Chang-hoon Lee

2004-01-01

79

Real-time quantitative differential holographic interferometry  

NASA Astrophysics Data System (ADS)

A real-time holographic interferometer has been developed for quantitative flow and wavefront diagnostics. The interferometer employs a new variety of the non-linear recording material, Bacteriorhodopsin, to not only record interferograms in real-time, but to analyze them in real- time as well, using an innovative adaption of Phase Shift Interferometry. The versatile interferometer can be configured as a real-time holographic interferometer for general applications and also as a high-speed, multiple pulsed interferometer for time differential applications, such as analyzing unsteady flow and turbulence. The versatility and relative low cost of the hardware components make the interferometer an attractive option for upgrading current schlieren flow visualization systems.

Brock, Neil J.; Millerd, James E.; Trolinger, James D.

1999-10-01

80

Real-Time Water Data  

NSDL National Science Digital Library

This site provides access to streamflow data for USGS (United States Geological Survey) streamflow monitoring sites around the United States. The data can be searched using an interactive map or by state. Most stations report Station Number, Station Name, long-term median flow, present flow stage, present water temperature, and the date and time of the last entry. Most stations also have stream flow statistics for the period of record including the latest flow, minimum flow, maximum flow, mean flow, and exceedance probabilities. Many stations also have links to the station description, annual peak streamflow data, and other historical data.

81

Analysis of real-time vibration data  

USGS Publications Warehouse

In recent years, a few structures have been instrumented to provide continuous vibration data in real time, recording not only large-amplitude motions generated by extreme loads, but also small-amplitude motions generated by ambient loads. The main objective in continuous recording is to track any changes in structural characteristics, and to detect damage after an extreme event, such as an earthquake or explosion. The Fourier-based spectral analysis methods have been the primary tool to analyze vibration data from structures. In general, such methods do not work well for real-time data, because real-time data are mainly composed of ambient vibrations with very low amplitudes and signal-to-noise ratios. The long duration, linearity, and the stationarity of ambient data, however, allow us to utilize statistical signal processing tools, which can compensate for the adverse effects of low amplitudes and high noise. The analysis of real-time data requires tools and techniques that can be applied in real-time; i.e., data are processed and analyzed while being acquired. This paper presents some of the basic tools and techniques for processing and analyzing real-time vibration data. The topics discussed include utilization of running time windows, tracking mean and mean-square values, filtering, system identification, and damage detection.

Safak, E.

2005-01-01

82

Real-time smart fluorescence sensor platform  

NASA Astrophysics Data System (ADS)

A novel compact LED array based light induced fluorescence (LIF) sensor has been developed for real-time in-line monitoring of intrinsic fluorophores in the solid and liquid state. The sensor is essential for on-the-spot, routine, and cost effective real-time analysis. The sensor is designed to provide real-time emission response along with various smart sensing parameters to ensure real-time measurement quality that is required for regulated GMP process monitoring applications. This work describes a LIF sensor tailored for solid-phase fluorometry. Fundamental figures of merit, excitation overexposure and smart sensing features required for modern process monitoring and control are discussed within the context of pharmaceutical solid-phase manufacturing and similar applications.

Dickens, Jason E.; Vaughn, Mike S.; Taylor, Mervin; Ponstingl, Mike

2011-05-01

83

Real Time Control of Reservoir Systems.  

National Technical Information Service (NTIS)

The development of a new method for the real time operation of reservoir systems is described. The method, called Extended Linear Quadratic Gaussian (ELQG) controller, draws on and extends stochastic control theory results, and is well suited for the opti...

A. P. Georgakakos D. H. Marks

1985-01-01

84

Scheduling for Embedded Real-Time Systems  

Microsoft Academic Search

The authors review several approaches to control-oriented and dataflow-oriented software scheduling to determine whether a given technique can satisfy deadlines, throughput, and other constraints for embedded real-time systems

Felice Balarin; Luciano Lavagno; Praveen K. Murthy; Alberto L. Sangiovanni-vincentelli

1998-01-01

85

Composing Synchroniztion and Real-Time Constraints.  

National Technical Information Service (NTIS)

This paper analyzes the origins of the problems in composing and reusing synchronization and real-time specifications, first as separate concerns, and later as composed behavior. To overcome the so-called inheritance anomaly problems, this paper proposes ...

L. Bergmans M. Aksit

1995-01-01

86

The Power of Real-time PCR  

NSDL National Science Digital Library

Description of basic concepts, chemistries, and instrumentation of real-time polymerase chain reaction. Also includes present applications and future perspectives for this technology in biomedical sciences and in life science education

Mark A. Valasek (University of Texas Southwestern Medical Center Department of Physiology, Touchstone Center for Diabetes Research); Joyce J. Repa (University of Texas Southwestern Medical Center Department of Internal Medicine,Touchstone Center for Diabetes Research,)

2005-09-01

87

Real-Time Video Tracking Concepts.  

National Technical Information Service (NTIS)

Real-time video (RTV) tracking concepts are developed for tracking high performance targets in noisy background scenes. Image processing techniques are combined with parallel processing methods to perform a statistical analysis of a TV image, partition th...

G. M. Flachs P. I. Perez R. B. Rogers S. J. Szymanski J. M. Taylor

1979-01-01

88

Real-Time Tactical Operating Systems Study.  

National Technical Information Service (NTIS)

This report reviews overall objectives accomplishments, and approach to CENTACS analysis efforts in real-time tactical operating systems. Included is a delineation of final report and a projection of resource expenditure for remainder of contractual effor...

C. W. Yeisley

1975-01-01

89

CRTF Real-Time Aperture Flux System.  

National Technical Information Service (NTIS)

The Real-Time Aperture Flux system (TRAF) is a test measurement system designed to determine the input power/unit area (flux density) during solar experiments conducted at the Central Receiver Test Facility, Sandia National Laboratories, Albuquerque, New ...

D. B. Davis

1980-01-01

90

Approach to Real-Time Holography.  

National Technical Information Service (NTIS)

Various diagnostic procedures in medicine, industry and defense produce 3-Dimensional data bases adequate to calculate a hologram. In most cases the nearer to real time the hologram can be produced the more beneficial. Since a hologram is a superposition ...

H. L. Davidson S. S. Friedland

1983-01-01

91

Real-Time Procedural Shading System.  

National Technical Information Service (NTIS)

Real-time graphics hardware is becoming programmable, but this programmable hardware is complex and difficult to use given current APIs. Higher level abstractions would both increase programmer productivity and make programs more portable. However, it is ...

K. Proudfoot W. R. Mark S. Tzvetkov P. Hanrahan

2001-01-01

92

Implementing Ada.Real_Time.Clock and Absolute Delays in Real-Time Kernels  

Microsoft Academic Search

A real-time kernel providing multitasking and timing services is a fundamental component of any real-time system. Timing services,\\u000a which are crucial to the correct execution of this kind of applications, are usually provided by a real-time clock and timer\\u000a manager, which is part of the kernel and implements the required functionality on top of the one or more hardware timers.

Juan Zamorano; José F. Ruiz; Juan Antonio De La Puente

2001-01-01

93

Proactive optimization of real-time video  

Microsoft Academic Search

In this paper, we introduce a new strategy for processing real-time video packets in programmable network nodes or active routers. We first discuss challenges in transmission of video streams over bandwidth-limited networks, followed by the active approach as an advance for streaming real-time video. In our model, each programmable node (or router) makes admission decision for video frames based on

Pham Van Tien

2005-01-01

94

Real-time interactive color flow MRI  

Microsoft Academic Search

The imaging method described is a combination of magnetic resonance (MR) velocity measurement, fast scanning, and image reconstruction techniques previously developed. Real-time interactive color flow magnetic resonance imaging (MRI) is a technique that combines grey-scale automatic MR images with a color overlay which maps blood velocity information. Real-time color flow MRI enables velocity information from vascular structures to be displayed

H. W. Korin; R. C. Wright; N. J. Hangiandreou; R. L. Ehman; S. J. Riederer

1991-01-01

95

Real-Time Competitive Evolutionary Computation  

Microsoft Academic Search

In this paper, a system of evolutionary computation will be presented that uses real-time competition to evolve individuals that effectively utilize the environment in which the competition takes place. This system can be used to create computer-controlled enemies for gaming systems with little programmer effort. The evolved individuals will be able to react to changes in the environment in real-time,

Adam Hewgill

2002-01-01

96

Real-time homogenous translucent material editing  

Microsoft Academic Search

This paper presents a novel method for real-time homogenous translucent material editing under fixed illumi- nation. We consider the complete analytic BSSRDF model proposed by Jensen et al. (JMLH01), including both multiple scattering and single scattering. Our method allows the user to adjust the analytic parameters of BSSRDF and provides high-quality, real-time rendering feedback. Inspired by recently developed Precomputed Radiance

Kun Xu; Yue Gao; Yong Li; Tao Ju; Shi-min Hu

2007-01-01

97

Real-time scheduling using minimum search  

NASA Technical Reports Server (NTRS)

In this paper we consider a simple model of real-time scheduling. We present a real-time scheduling system called RTS which is based on Korf's Minimin algorithm. Experimental results show that the schedule quality initially improves with the amount of look-ahead search and tapers off quickly. So it sppears that reasonably good schedules can be produced with a relatively shallow search.

Tadepalli, Prasad; Joshi, Varad

1992-01-01

98

Real-Time Index Concurrency Control  

Microsoft Academic Search

Real-time database systems are expected to rely heavily on indexes to speed up data access and, thereby, help more transactions meet their deadlines. Accordingly, high-performance index concurrency control (ICC) protocols are required to prevent contention for the index from becoming a bottleneck. In this paper, we develop real-time variants of a representative set of classical B-tree ICC protocols and, using

Jayant R. Haritsa; S. Seshadri

2000-01-01

99

Synthesizing controllers from real-time specifications  

Microsoft Academic Search

We present an algorithm for synthesising real-time controllers specified in a subset of the interval temporal logic Duration Calculus. The synthesised controllers are given in terms of PLC-Automata, which are an abstract description of programs of polling machines. PLC-Automata can be implemented directly on Programmable Logic Controllers (PLCs), a special kind of polling real-time controllers which are often used in

Henning Dierks

1999-01-01

100

Geodynamic monitoring in real times  

NASA Astrophysics Data System (ADS)

For the decision of problems of the short-term and intermediate term forecast of tectonic earthquakes the technique conditionally named - geodynamic monitoring which does not use the data of seismic monitoring for the operative decision of problems of the forecast is offered. Geodynamic monitoring (GDM) is to studying tensely - deformed conditions of the separate block of rock on change of activity natural radioactive gas is carried out by accommodation in the chosen file of specially designed monitors of radon - devices fixing change in time (VAR). The monitor of radon, (the detector of radon) as the basic measuring device located in the block of rocks, possesses enormous tensosensitivity to relative strain condition of a file. Depending on the enclosed pressure choose three characteristic points: 1) 30-35 % of "background" size VAR - the beginning of accumulation of inelastic energy; 2) 50 % of background VAR - the process of stabilization of an elastic condition of a file; 3) 70-75 % "background" VAR - a critical pressure in the mountain block, an opportunity as spontaneous dump of elastic energy, and under action external "triggerring" forces. If the size of the saved up energy is close to critical dump needs energy at a level of energy of variations of rotation of the Earth. Such significant energy causes "plenty" of earthquakes on all planet simultaneously. This fact confirms an opportunity of the short-term forecast of strong (destructive) earthquakes: dump of elastic pressure of the Earth in this case occurs in 25-30 hours after passage of variations of rotation of the Earth. It is for the notification of the population about coming nearer earthquake. External power functions (mechanical, electromagnetic, etc.), preparations influencing system and occurrence of tectonic earthquakes, are divided on two big classes: 1) "forecasting " functions - processes functionally connected to accumulation of elastic pressure and to dump by its rather small dozes; 2) external mechanical actions which initiate dump of the saved up elastic pressure - "triggirring functions", promoting dump of the elastic pressure resulting in earthquake. The short-term forecast of especially large earthquakes is entirely based on use of monitoring of rotation of the Earth: essential "triggerring functions" (variations of rotation of the Earth) dump(reset) the saved up pressure on all surface of the Earth, causing thus large earthquakes. Therefore the prevention(warning) of large earthquakes should be formed on the basis of monitoring variations of heterogeneity of rotation of the Earth, that usually precedes dump of elastic pressure(voltage) at 25-30 o'clock.

Outkin, V.; Yurkov, A.; Klimshin, A.; Kozlova, I.

2011-12-01

101

Rephrasing Faraday's Law  

NASA Astrophysics Data System (ADS)

As physics educators, we must often find the balance between simplicity and accuracy. Particularly in introductory courses, it can be a struggle to give students the level of understanding for which they're ready without misrepresenting reality. Of course, it's in these introductory courses that our students begin to construct the conceptual framework that they'll flesh out over a physics curriculum. So a misrepresentation at this early stage will seed difficulties and stubborn misconceptions that can persist or even strengthen through subsequent courses, especially since many upper-level texts focus more on techniques and would not directly challenge mistaken concepts. In the worst cases, our students retain misunderstandings past graduation, and even pass them on to their own students. One important case is the common representation of Faraday's law as showing that a time-varying magnetic field causes a circulating electric field.

Hill, S. Eric

2010-09-01

102

Real-time GPS monitoring throughout Cascadia  

NASA Astrophysics Data System (ADS)

Over 400 GPS receivers of the combined PANGA and PBO networks currently operate along the Cascadia subduction zone, all of which are high-rate and telemetered in real-time. These receivers span the M9 megathrust, M7 crustal faults beneath population centers, several active Cascades volcanoes, and a host of other hazard sources, and together enable a host of new approaches towards hazards mitigation. Data from the majority of the stations is received in real time at CWU and processed into one-second position estimates using 1) relative positioning within several reference frames constrained by 2) absolute point positioning using streamed satellite orbit and clock corrections. While the former produces lower-noise time series, for earthquakes greater than ~M7 and ground displacements exceeding ~20 cm, point positioning alone is shown to provide very rapid and robust estimates of the location and amplitude of both dynamic strong ground motion and permanent deformation. Raw phase and range observables from stations throughout Cascadia are being processed in real time at JPL and CWU into station positions, which in turn are analyzed also in real-time for earthquake processes at CWU. Our efforts can be broken down into three distinct areas: 1) Real-time point-positioning methodologies, 2) a data aggregator that captures real-time position streams from a variety of processing centers and methodologies (JPL RTGipsy, CWU rtPP, Trimble VRS) and re-streams the data as configurable streams to application clients out anywhere on the web, and 3) a suite of analysis tools that operate on the real-time position streams, including plotting, vectors, peak ground deformation contouring, and finite-fault inversions. This suite is currently bundled within a single client written in JAVA, called 'GPS Cockpit.'

Melbourne, T. I.; Santillan, V. M.; Scrivner, C. W.; Szeliga, W. M.; Webb, F.; Abundiz, S.

2012-12-01

103

REAL TIME SYSTEM OPERATIONS 2006-2007  

SciTech Connect

The Real Time System Operations (RTSO) 2006-2007 project focused on two parallel technical tasks: (1) Real-Time Applications of Phasors for Monitoring, Alarming and Control; and (2) Real-Time Voltage Security Assessment (RTVSA) Prototype Tool. The overall goal of the phasor applications project was to accelerate adoption and foster greater use of new, more accurate, time-synchronized phasor measurements by conducting research and prototyping applications on California ISO's phasor platform - Real-Time Dynamics Monitoring System (RTDMS) -- that provide previously unavailable information on the dynamic stability of the grid. Feasibility assessment studies were conducted on potential application of this technology for small-signal stability monitoring, validating/improving existing stability nomograms, conducting frequency response analysis, and obtaining real-time sensitivity information on key metrics to assess grid stress. Based on study findings, prototype applications for real-time visualization and alarming, small-signal stability monitoring, measurement based sensitivity analysis and frequency response assessment were developed, factory- and field-tested at the California ISO and at BPA. The goal of the RTVSA project was to provide California ISO with a prototype voltage security assessment tool that runs in real time within California ISO?s new reliability and congestion management system. CERTS conducted a technical assessment of appropriate algorithms, developed a prototype incorporating state-of-art algorithms (such as the continuation power flow, direct method, boundary orbiting method, and hyperplanes) into a framework most suitable for an operations environment. Based on study findings, a functional specification was prepared, which the California ISO has since used to procure a production-quality tool that is now a part of a suite of advanced computational tools that is used by California ISO for reliability and congestion management.

Eto, Joseph H.; Parashar, Manu; Lewis, Nancy Jo

2008-08-15

104

Characterization of real-time computers  

NASA Technical Reports Server (NTRS)

A real-time system consists of a computer controller and controlled processes. Despite the synergistic relationship between these two components, they have been traditionally designed and analyzed independently of and separately from each other; namely, computer controllers by computer scientists/engineers and controlled processes by control scientists. As a remedy for this problem, in this report real-time computers are characterized by performance measures based on computer controller response time that are: (1) congruent to the real-time applications, (2) able to offer an objective comparison of rival computer systems, and (3) experimentally measurable/determinable. These measures, unlike others, provide the real-time computer controller with a natural link to controlled processes. In order to demonstrate their utility and power, these measures are first determined for example controlled processes on the basis of control performance functionals. They are then used for two important real-time multiprocessor design applications - the number-power tradeoff and fault-masking and synchronization.

Shin, K. G.; Krishna, C. M.

1984-01-01

105

Estimating probabilistic timing performance for real-time embedded systems  

Microsoft Academic Search

In system-level design of real-time embedded systems, being able to capture the interactions among the tasks with respect to timing constraints and determine the overall system timing performance is a major challenge. Most previous works in the area are either based on a fixed execution time model or are only concerned with the probabilistic timing behavior of each individual task.

Xiaobo Sharon Hu; Tao Zhou; Edwin Hsing-mean Sha

2001-01-01

106

Visualization of Real-Time Data  

NASA Technical Reports Server (NTRS)

In this project we explored various approaches to presenting real-time data from the numerous systems monitored on the space shuttle to computer users. We examined the approach that several projects at the Kennedy Space Center (KSC) used to accomplish this. We undertook to build a prototype system to demonstrate that the Internet and the Java programming language could be used to present the real-time data conveniently. Several Java programs were developed that presented real-time data in different forms including one form that emulated the display screens of the PC GOAL system which is familiar to many at KSC. Also, we developed several communications programs to supply the data continuously. Furthermore, a framework was created using the World Wide Web (WWW) to organize the collection and presentation of the real-time data. We believe our demonstration project shows the great flexibility of the approach. We had no particular use of the data in mind, instead we wanted the most general and the least complex framework possible. People who wish to view data need only know how to use a WWW browser and the address (the URL). People wanting to build WWW documents containing real-time data need only know the values of a few parameters, they do not need to program in Java or any other language. These are stunning advantages over more monolithic systems.

Stansifer, Ryan; Engrand, Peter

1996-01-01

107

Real-time Enhanced Vision System  

NASA Technical Reports Server (NTRS)

Flying in poor visibility conditions, such as rain, snow, fog or haze, is inherently dangerous. However these conditions can occur at nearly any location, so inevitably pilots must successfully navigate through them. At NASA Langley Research Center (LaRC), under support of the Aviation Safety and Security Program Office and the Systems Engineering Directorate, we are developing an Enhanced Vision System (EVS) that combines image enhancement and synthetic vision elements to assist pilots flying through adverse weather conditions. This system uses a combination of forward-looking infrared and visible sensors for data acquisition. A core function of the system is to enhance and fuse the sensor data in order to increase the information content and quality of the captured imagery. These operations must be performed in real-time for the pilot to use while flying. For image enhancement, we are using the LaRC patented Retinex algorithm since it performs exceptionally well for improving low-contrast range imagery typically seen during poor visibility conditions. In general, real-time operation of the Retinex requires specialized hardware. To date, we have successfully implemented a single-sensor real-time version of the Retinex on several different Digital Signal Processor (DSP) platforms. In this paper we give an overview of the EVS and its performance requirements for real-time enhancement and fusion and we discuss our current real-time Retinex implementations on DSPs.

Hines, Glenn D.; Rahman, Zia-Ur; Jobson, Daniel J.; Woodell, Glenn A.; Harrah, Steven D.

2005-01-01

108

Hard Real-Time: C++ Versus RTSJ  

NASA Technical Reports Server (NTRS)

In the domain of hard real-time systems, which language is better: C++ or the Real-Time Specification for Java (RTSJ)? Although ordinary Java provides a more productive programming environment than C++ due to its automatic memory management, that benefit does not apply to RTSJ when using NoHeapRealtimeThread and non-heap memory areas. As a result, RTSJ programmers must manage non-heap memory explicitly. While that's not a deterrent for veteran real-time programmers-where explicit memory management is common-the lack of certain language features in RTSJ (and Java) makes that manual memory management harder to accomplish safely than in C++. This paper illustrates the problem for practitioners in the context of moving data and managing memory in a real-time producer/consumer pattern. The relative ease of implementation and safety of the C++ programming model suggests that RTSJ has a struggle ahead in the domain of hard real-time applications, despite its other attractive features.

Dvorak, Daniel L.; Reinholtz, William K.

2004-01-01

109

Enhancing Real-Time CORBA via Optimization Strategies and Real-Time Java features  

Microsoft Academic Search

End-to-end middleware predictability is essential to support quality of service (QoS) capabilities needed by distributed real-time and embedded (DRE) applications. Real-time CORBA is a middleware standard that allows DRE applica- tions to allocate, schedule, and control the QoS of CPU, mem- ory, and networking resources. Existing Real-time CORBA solutions are implemented in C++, which is generally more complicated and error-prone

Arvind S. Krishna; Raymond Klefstad; Douglas C. Schmidt

2004-01-01

110

Enhancing Real-Time CORBA via Real-Time Java Features  

Microsoft Academic Search

End-to-end middleware predictability is essential to support quality of service (QoS) capabilities needed by dis- tributed real-time and embedded (DRE) applications. Real-time CORBA is a middleware standard that allows DRE applications to allocate, schedule, and control the QoS of CPU, memory, and networking resources. Existing Real-time CORBA solutions are implemented in C++, which is generally more complicated and error-prone to

Arvind S. Krishna; Douglas C. Schmidt; Raymond Klefstad

2004-01-01

111

Development and first experimental tests of Faraday cup array  

NASA Astrophysics Data System (ADS)

A new type of Faraday cup, capable of detecting high energy charged particles produced in a high intensity laser-matter interaction environment, has recently been developed and demonstrated as a real-time detector based on the time-of-flight technique. An array of these Faraday cups was designed and constructed to cover different observation angles with respect to the target normal direction. Thus, it allows reconstruction of the spatial distribution of ion current density in the subcritical plasma region and the ability to visualise its time evolution through time-of-flight measurements, which cannot be achieved with standard laser optical interferometry. This is a unique method for two-dimensional visualisation of ion currents from laser-generated plasmas. A technical description of the new type of Faraday cup is introduced along with an ad hoc data analysis procedure. Experimental results obtained during campaigns at the Petawatt High-Energy Laser for Heavy Ion Experiments (GSI, Darmstadt) and at the Prague Asterix Laser System (AS CR) are presented. Advantages and limitations of the used diagnostic system are discussed.

Prokůpek, J.; Kaufman, J.; Margarone, D.; Krůs, M.; Velyhan, A.; Krása, J.; Burris-Mog, T.; Busold, S.; Deppert, O.; Cowan, T. E.; Korn, G.

2014-01-01

112

Development and first experimental tests of Faraday cup array.  

PubMed

A new type of Faraday cup, capable of detecting high energy charged particles produced in a high intensity laser-matter interaction environment, has recently been developed and demonstrated as a real-time detector based on the time-of-flight technique. An array of these Faraday cups was designed and constructed to cover different observation angles with respect to the target normal direction. Thus, it allows reconstruction of the spatial distribution of ion current density in the subcritical plasma region and the ability to visualise its time evolution through time-of-flight measurements, which cannot be achieved with standard laser optical interferometry. This is a unique method for two-dimensional visualisation of ion currents from laser-generated plasmas. A technical description of the new type of Faraday cup is introduced along with an ad hoc data analysis procedure. Experimental results obtained during campaigns at the Petawatt High-Energy Laser for Heavy Ion Experiments (GSI, Darmstadt) and at the Prague Asterix Laser System (AS CR) are presented. Advantages and limitations of the used diagnostic system are discussed. PMID:24517754

Prok?pek, J; Kaufman, J; Margarone, D; Kr?s, M; Velyhan, A; Krása, J; Burris-Mog, T; Busold, S; Deppert, O; Cowan, T E; Korn, G

2014-01-01

113

Feedback as Real-Time Constructions  

ERIC Educational Resources Information Center

This article offers a re-description of feedback and the significance of time in feedback constructions based on systems theory. It describes feedback as internal, real-time constructions in a learning system. From this perspective, feedback is neither immediate nor delayed, but occurs in the very moment it takes place. This article argues for a…

Keiding, Tina Bering; Qvortrup, Ane

2014-01-01

114

Real Time Pattern Matching Using Projection Kernels  

Microsoft Academic Search

Abstract A novel approach to pattern matching is presented, which reduces time complexity by two orders of magnitude, compared to traditional approaches, enabling real-time performance. The suggested approach uses an ecien t projection scheme which allows the distance between a pattern and a window to be bounded ecien tly from below. The projection scheme is combined with a rejection framework

Yacov Hel-or; Hagit Hel-or

2003-01-01

115

Java and Real Time Storage Applications  

Microsoft Academic Search

Storage systems have storage devices which run real time embedded software. Most storage devices use C and occasionally C++ to manage and control the storage device. Software for the storage device must meet the time and resource constraints of the storage device. The prevailing wisdom in the embedded world is that objects and in particular Java only work for simple

Gary Mueller; Janet Borzuchowski

2002-01-01

116

Real-time coherent OFDM transmission  

NASA Astrophysics Data System (ADS)

We review the recent development in real-time coherent optical OFDM (CO-OFDM) transmission for their algorithm and implementation. The unique challenge of real-time implementation of OFDM for high speed optical data transmission including relatively large phase noise, frequency offset and dynamically changing optical channels are discussed. The fundamental digital signal processing (DSP) architectures of transmitter and receiver are presented in the manner achievable in state of the art field-programmable gate arrays (FPGAs) or application-specific integrated circuits (ASICs). Primary DSP components' algorithms and implementations are presented and discussed. The successful demonstration of real-time CO-OFDM receivers includes a receiver with sampling rate of 2.5-Gsamples/s to receive a 3.55-Gb/s single channel and 53.3-Gb/s multi-band CO-OFDM signal.

Kaneda, Noriaki; Pfau, Timo; Yang, Qi; Chen, Y. K.

2011-01-01

117

Continuous, real time microwave plasma element sensor  

DOEpatents

Microwave-induced plasma for continuous, real time trace element monitoring under harsh and variable conditions. The sensor includes a source of high power microwave energy and a shorted waveguide made of a microwave conductive, refractory material communicating with the source of the microwave energy to generate a plasma. The high power waveguide is constructed to be robust in a hot, hostile environment. It includes an aperture for the passage of gases to be analyzed and a spectrometer is connected to receive light from the plasma. Provision is made for real time in situ calibration. The spectrometer disperses the light, which is then analyzed by a computer. The sensor is capable of making continuous, real time quantitative measurements of desired elements, such as the heavy metals lead and mercury.

Woskov, Paul P. (4 Ledgewood Dr., Bedford, MA 01730); Smatlak, Donna L. (10 Village Hill Rd., Belmont, MA 02178); Cohn, Daniel R. (26 Walnut Hill Rd., Chestnut Hill, MA 02167); Wittle, J. Kenneth (1740 Conestoga Rd., Chester Springs, PA 19425); Titus, Charles H. (323 Echo Valley La., Newton Square, PA 19072); Surma, Jeffrey E. (806 Brian La., Kennewick, WA 99337)

1995-01-01

118

Durham adaptive optics real-time controller.  

PubMed

The Durham adaptive optics (AO) real-time controller was initially a proof of concept design for a generic AO control system. It has since been developed into a modern and powerful central-processing-unit-based real-time control system, capable of using hardware acceleration (including field programmable gate arrays and graphical processing units), based primarily around commercial off-the-shelf hardware. It is powerful enough to be used as the real-time controller for all currently planned 8 m class telescope AO systems. Here we give details of this controller and the concepts behind it, and report on performance, including latency and jitter, which is less than 10 ?s for small AO systems. PMID:21068868

Basden, Alastair; Geng, Deli; Myers, Richard; Younger, Eddy

2010-11-10

119

The real-time Neutron Monitor database  

NASA Astrophysics Data System (ADS)

In January 2007 the Real time database for high-resolution neutron monitor measurements (NMDB) project, which is supported by the 7th framework program of the European Commission, commenced. One year after the project start we have several neutron monitor stations that are sending their data in real-time to a publicly available prototype database in a common format. We have developed applications that make use of the real-time cosmic ray measurements for example for space weather applications and dose calculations at airplane altitudes. We are also in the process of establishing a public outreach site and a training site with material for university students and researchers and engineers who want to get familiar with cosmic rays and neutron monitor measurements. An overview of the project status as well as instructions on how to use the available data will be given. Possible future developments will be briefly discussed.

Klein, K.-L.; Steigies, C.; Nmdb Team

2009-04-01

120

Real-Time Visualization of Tissue Ischemia  

NASA Technical Reports Server (NTRS)

A real-time display of tissue ischemia which comprises three CCD video cameras, each with a narrow bandwidth filter at the correct wavelength is discussed. The cameras simultaneously view an area of tissue suspected of having ischemic areas through beamsplitters. The output from each camera is adjusted to give the correct signal intensity for combining with, the others into an image for display. If necessary a digital signal processor (DSP) can implement algorithms for image enhancement prior to display. Current DSP engines are fast enough to give real-time display. Measurement at three, wavelengths, combined into a real-time Red-Green-Blue (RGB) video display with a digital signal processing (DSP) board to implement image algorithms, provides direct visualization of ischemic areas.

Bearman, Gregory H. (Inventor); Chrien, Thomas D. (Inventor); Eastwood, Michael L. (Inventor)

2000-01-01

121

Continuous, real time microwave plasma element sensor  

DOEpatents

Microwave-induced plasma is described for continuous, real time trace element monitoring under harsh and variable conditions. The sensor includes a source of high power microwave energy and a shorted waveguide made of a microwave conductive, refractory material communicating with the source of the microwave energy to generate a plasma. The high power waveguide is constructed to be robust in a hot, hostile environment. It includes an aperture for the passage of gases to be analyzed and a spectrometer is connected to receive light from the plasma. Provision is made for real time in situ calibration. The spectrometer disperses the light, which is then analyzed by a computer. The sensor is capable of making continuous, real time quantitative measurements of desired elements, such as the heavy metals lead and mercury. 3 figs.

Woskov, P.P.; Smatlak, D.L.; Cohn, D.R.; Wittle, J.K.; Titus, C.H.; Surma, J.E.

1995-12-26

122

Network protocols for real-time applications  

NASA Technical Reports Server (NTRS)

The Fiber Distributed Data Interface (FDDI) and the SAE AE-9B High Speed Ring Bus (HSRB) are emerging standards for high-performance token ring local area networks. FDDI was designed to be a general-purpose high-performance network. HSRB was designed specifically for military real-time applications. A workshop was conducted at NASA Ames Research Center in January, 1987 to compare and contrast these protocols with respect to their ability to support real-time applications. This report summarizes workshop presentations and includes an independent comparison of the two protocols. A conclusion reached at the workshop was that current protocols for the upper layers of the Open Systems Interconnection (OSI) network model are inadequate for real-time applications.

Johnson, Marjory J.

1987-01-01

123

Real Time Linux - The RTOS for Astronomy?  

NASA Astrophysics Data System (ADS)

The BoF was attended by about 30 participants and a free CD of real time Linux-based upon RedHat 5.2-was available. There was a detailed presentation on the nature of real time Linux and the variants for hard real time: New Mexico Tech's RTL and DIAPM's RTAI. Comparison tables between standard Linux and real time Linux responses to time interval generation and interrupt response latency were presented (see elsewhere in these proceedings). The present recommendations are to use RTL for UP machines running the 2.0.x kernels and RTAI for SMP machines running the 2.2.x kernel. Support, both academically and commercially, is available. Some known limitations were presented and the solutions reported e.g., debugging and hardware support. The features of RTAI (scheduler, fifos, shared memory, semaphores, message queues and RPCs) were described. Typical performance statistics were presented: Pentium-based oneshot tasks running > 30kHz, 486-based oneshot tasks running at ~ 10 kHz, periodic timer tasks running in excess of 90 kHz with average zero jitter peaking to ~ 13 mus (UP) and ~ 30 mus (SMP). Some detail on kernel module programming, including coding examples, were presented showing a typical data acquisition system generating simulated (random) data writing to a shared memory buffer and a fifo buffer to communicate between real time Linux and user space. All coding examples were complete and tested under RTAI v0.6 and the 2.2.12 kernel. Finally, arguments were raised in support of real time Linux: it's open source, free under GPL, enables rapid prototyping, has good support and the ability to have a fully functioning workstation capable of co-existing hard real time performance. The counter weight-the negatives-of lack of platforms (x86 and PowerPC only at present), lack of board support, promiscuous root access and the danger of ignorance of real time programming issues were also discussed. See ftp://orion.tuc.noao.edu/pub/pnd/rtlbof.tgz for the StarOffice overheads for this presentation.

Daly, P. N.

124

Real-Time Elastography of the Prostate  

PubMed Central

Palpation of organs is one of the oldest clinical examination techniques, for instance, if you think of the palpation of the breast or the digital rectal examination of the prostate, where hard palpable regions are suspicious for cancer. This is the basic principle of real-time elastography, an ultrasound technique, which is able to visualise tissue elasticity. Since prostate cancer features an increased stiffness due to the higher cell and vessel density than the normal surrounding tissue, real-time elastography has been used for several years for prostate cancer detection. This review introduces the different techniques of ultrasound elastography and furthermore summarises its limitations and potentials.

Junker, D.; De Zordo, T.; Quentin, M.; Ladurner, M.; Bektic, J.; Horniger, W.; Jaschke, W.; Aigner, F.

2014-01-01

125

Note: Real-time absolute air refractometer.  

PubMed

We present a real-time absolute air refractometer benefiting from the synthetic pseudo-wavelength (SPW) method. Based on laser heterodyne interferometry, the SPW method uses three vacuum cells with specific lengths to synthesize a set of synthetic pseudo-wavelengths, by combination of which the refractive index can be determined directly without ambiguity. In addition, owing to the parallel arrangement of the vacuum cells in the optical path, the measured data can be collected simultaneously so that one measurement process can be less than 2 ms. The real-time feature makes it possible for instantaneous compensation for laser interferometers. PMID:24880432

Huang, Pei; Zhang, Jitao; Li, Yan; Wei, Haoyun

2014-05-01

126

Machine vision for real time orbital operations  

NASA Technical Reports Server (NTRS)

Machine vision for automation and robotic operation of Space Station era systems has the potential for increasing the efficiency of orbital servicing, repair, assembly and docking tasks. A machine vision research project is described in which a TV camera is used for inputing visual data to a computer so that image processing may be achieved for real time control of these orbital operations. A technique has resulted from this research which reduces computer memory requirements and greatly increases typical computational speed such that it has the potential for development into a real time orbital machine vision system. This technique is called AI BOSS (Analysis of Images by Box Scan and Syntax).

Vinz, Frank L.

1988-01-01

127

Real-Time, Interactive Sonic Boom Display  

NASA Technical Reports Server (NTRS)

The present invention is an improved real-time, interactive sonic boom display for aircraft. By using physical properties obtained via various sensors and databases, the invention determines, in real-time, sonic boom impacts locations and intensities for aircraft traveling at supersonic speeds. The information is provided to a pilot via a display that lists a selectable set of maneuvers available to the pilot to mitigate sonic boom issues. Upon selection of a maneuver, the information as to the result of the maneuver is displayed and the pilot may proceed with making the maneuver, or provide new data to the system in order to calculate a different maneuver.

Haering, Jr., Edward A. (Inventor); Plotkin, Kenneth J. (Inventor)

2012-01-01

128

Giant plateau in the terahertz Faraday angle in gated Bi2Se3  

NASA Astrophysics Data System (ADS)

We report gated terahertz Faraday angle measurements on epitaxial Bi2Se3 thin films capped with In2Se3. A plateau is observed in the real part of the Faraday angle at an onset gate voltage corresponding to no band bending at the surface, which persists into accumulation. The plateau is two orders of magnitude flatter than the step size expected from a single Landau level in the low-frequency limit, quantized in units of the fine structure constant. At 8 T, the plateau extends over a range of gate voltage that spans an electron density greater than 14 times the quantum flux density. Both the imaginary part of the Faraday angle and transmission measurements indicate dissipative off-axis and longitudinal conductivity channels associated with the plateau.

Jenkins, Gregory S.; Sushkov, Andrei B.; Schmadel, Don C.; Kim, M.-H.; Brahlek, Matthew; Bansal, Namrata; Oh, Seongshik; Drew, H. Dennis

2012-12-01

129

OPAD-EDIFIS Real-Time Processing  

NASA Technical Reports Server (NTRS)

The Optical Plume Anomaly Detection (OPAD) detects engine hardware degradation of flight vehicles through identification and quantification of elemental species found in the plume by analyzing the plume emission spectra in a real-time mode. Real-time performance of OPAD relies on extensive software which must report metal amounts in the plume faster than once every 0.5 sec. OPAD software previously written by NASA scientists performed most necessary functions at speeds which were far below what is needed for real-time operation. The research presented in this report improved the execution speed of the software by optimizing the code without changing the algorithms and converting it into a parallelized form which is executed in a shared-memory multiprocessor system. The resulting code was subjected to extensive timing analysis. The report also provides suggestions for further performance improvement by (1) identifying areas of algorithm optimization, (2) recommending commercially available multiprocessor architectures and operating systems to support real-time execution and (3) presenting an initial study of fault-tolerance requirements.

Katsinis, Constantine

1997-01-01

130

Real-time car detection system  

NASA Astrophysics Data System (ADS)

This paper presents a car detection system that is able to work in close to real-time on a smart camera. A cascade of histograms of oriented gradients was used as a detector. The algorithm and code were optimized for speed to meet the real-time constraints, without loosing too much on detection quality. The system is now able to process 10 frames per second on an Atom Z530 (1.6 GHz) processor used in the smart camera. The application on which the paper is based is ready to detect cars in real world scenarios. It is planned to extend it to also track and analyze the driver behavior patterns.

Rosner, Marcin

2011-01-01

131

The Flexible Faraday Cage  

Microsoft Academic Search

The Faraday ice-pail experiment is performed when studying the distribution of charges in conductors: Inside a hollow conductor the net charge is zero, and any excess charge resides on the outside surface.

Paul Gluck

2004-01-01

132

Michael Faraday, media man.  

PubMed

Michael Faraday was an enthusiastic portrait collector, and he welcomed the invention of photography not only as a possible means of recording observations accurately, but also as a method for advertising science and its practitioners. This article (which is part of the Science in the Industrial Revolution series) shows that like many eminent scientists, Faraday took advantage of the burgeoning Victorian media industry by posing in various roles. PMID:16332391

Fara, Patricia

2006-03-01

133

Real-time PCR in virology  

Microsoft Academic Search

The use of the polymerase chain reaction (PCR) in molecular diagnostics has increased to the point where it is now accepted as the gold standard for detecting nucleic acids from a number of origins and it has become an essential tool in the research labora- tory. Real-time PCR has engendered wider acceptance of the PCR due to its improved rapidity,

Ian M. Mackay; Katherine E. Arden; Andreas Nitsche

2002-01-01

134

Real-Time Operating System/360  

NASA Technical Reports Server (NTRS)

RTOS has a cost savings advantage for real-time applications, such as those with random inputs requiring a flexible data routing facility, display systems simplified by a device independent interface language, and complex applications needing added storage protection and data queuing.

Hoffman, R. L.; Kopp, R. S.; Mueller, H. H.; Pollan, W. D.; Van Sant, B. W.; Weiler, P. W.

1969-01-01

135

Real Time Grid Reliability Management 2005  

SciTech Connect

The increased need to manage California?s electricity grid in real time is a result of the ongoing transition from a system operated by vertically-integrated utilities serving native loads to one operated by an independent system operator supporting competitive energy markets. During this transition period, the traditional approach to reliability management -- construction of new transmission lines -- has not been pursued due to unresolved issues related to the financing and recovery of transmission project costs. In the absence of investments in new transmission infrastructure, the best strategy for managing reliability is to equip system operators with better real-time information about actual operating margins so that they can better understand and manage the risk of operating closer to the edge. A companion strategy is to address known deficiencies in offline modeling tools that are needed to ground the use of improved real-time tools. This project: (1) developed and conducted first-ever demonstrations of two prototype real-time software tools for voltage security assessment and phasor monitoring; and (2) prepared a scoping study on improving load and generator response models. Additional funding through two separate subsequent work authorizations has already been provided to build upon the work initiated in this project.

Eto, Joe; Eto, Joe; Lesieutre, Bernard; Lewis, Nancy Jo; Parashar, Manu

2008-07-07

136

Real-Time Control of Resonance in \\  

Microsoft Academic Search

Active Strain Energy Tuning (ASET) using Shape-Memory Actuators has been proposed for the vibration control of 'smart' composite structures. This paper presents preliminary experimental measurements on some simple prototype SMA hybrid 'Smart' structures. The results confirm previous modelling and show that ASET can indeed be used to control vibration characteristics. The most significant control mechanism appears to be real- time

C. M. Friend; P. J. Armstrong

1997-01-01

137

Real-time analysis of telemetry data  

NASA Technical Reports Server (NTRS)

This paper descibes a knowledge-based system for performing real-time monitoring and analysis of telemetry data from the NASA Hubble Space Telescope (HST). In order to handle asynchronous inputs and perform in real time the system consists of three or more separate processes, which run concurrently and communicate via a message passing scheme. The data management process gathers, compresses, and scales the incoming telemetry data befoe sending it to the other tasks. The inferencing process uses the incoming data to perform a real-time analysis of the state and health of the Space Telescope. The I/O process receives telemetry monitors from the data management process, updates its graphical displays in real time, and acts as the interface to the console operator. The three processes may run on the same or different computers. This system is currently under development and is being used to monitor testcases produced by the Bass Telemetry System in the Hardware/Software Integration Facility at Lockheed Missile and Space Co. in Sunnyvale, California.

Kao, Simon A.; Laffey, Thomas J.; Schmidt, James L.; Read, Jackson Y.; Dunham, Larry L.

1987-01-01

138

Real-time Simulation of Wrinkles  

Microsoft Academic Search

Skin wrinkles add realism and expressiveness to 3D facial animation. Modeling and animation of facial wrinkles have been challenging tasks due to the variety of conformations and details subtleness that wrinkles can exhibit. In this paper, we describe a method for real-time simulation of wrinkles taking advantage of the processing power of current GPUs. Our approach is based on a

Clausius Duque; G. Reis; José Mario De Martino

139

Real-time closed-world tracking  

Microsoft Academic Search

A real-time tracking algorithm that uses contextual in- formation is described. The method is capable of simul- taneously tracking multiple, non-rigid objects when erratic movement and object collisions are common. A closed- world assumption is used to adaptively select and weight image features used for correspondence. Results of algo- rithm testing and the limitationsof the method are discussed. The algorithm

Stephen S. Intille; James W. Davis; Aaron F. Bobick

1997-01-01

140

Development of real-time photoacoustic microscopy  

Microsoft Academic Search

Photoacoustic tomography detecting ultrasound signals generated from photon absorption provides optical absorption contrast in vivo for structural, functional and molecular imaging. Although photoacoustic tomography technology has grown fast in recent years, real-time photoacoustic imaging with cellular spatial resolution are still strongly demanded. We developed a photoacoustic microscopy which has video-rate imaging capability with cellular spatial resolution. The system consists of

Lidai Wang; Konstantin Maslov; Junjie Yao; Li Li; Lihong V. Wang

2011-01-01

141

Real-time intraoperative neurophysiological monitoring.  

PubMed

We discuss the utilization of signal processing techniques during surgical procedures. These techniques are used to provide real-time monitoring of nervous system function. We describe the historical development of these techniques and the hardware and software that have been used to implement them. PMID:11812210

Krieger, D; Sclabassi, R J

2001-10-01

142

A Survey of Real-Time Shading  

Microsoft Academic Search

This paper discusses different techniques being used today to mimic all the subtle elements of a photorealistic image that are traditionally missing in a real-time generated one. We focus on issues of surface modeling and especially bump and horizon mapping, recent reflection modeling approaches, and illumination with environment mapping. We also take a look at popular shadow generation techniques. In

Jan Jukka Kainulainen

143

Automated Testing of Real-Time Tasks  

Microsoft Academic Search

The development of embedded systems is a crucial area of responsibility in industrial practice. Many embedded systems need to meet real-time requirements. This adds a new dimension to the testing of such systems - not only the logical behavior, but also the temporal behavior of these systems requires thorough testing. In comparison with conventional software systems, the testing of embedded

Joachim Wegener; Roman Pitschinetz; Harmen Sthamer

2000-01-01

144

The Power of Real-Time PCR  

ERIC Educational Resources Information Center

In recent years, real-time polymerase chain reaction (PCR) has emerged as a robust and widely used methodology for biological investigation because it can detect and quantify very small amounts of specific nucleic acid sequences. As a research tool, a major application of this technology is the rapid and accurate assessment of changes in gene…

Valasek, Mark A.; Repa, Joyce J.

2005-01-01

145

REAL TIME CONTROL OF URBAN DRAINAGE NETWORKS  

EPA Science Inventory

Real-time control (RTC) is a custom-designed, computer-assisted management technology for a specific sewerage network to meet the operational objectives of its collection/conveyance system. RTC can operate in several modes, including a mode that is activated during a wet weather ...

146

Real-time computation of Zernike moments  

Microsoft Academic Search

Zernike moments have been proven to be very powerful image descriptors. However, their computational complexity makes them unsuitable for real-time applications. In this paper, a mathematical relationship between geometric and Zernike moments is extracted. In this way, the computation of geometric moments is adequate to derive Zernike moments. Since geometric moments can be efficiently implemented in hardware and their calculation

Leonidas G. Kotoulas; Ioannis Andreadis

2005-01-01

147

Minimizing Response Times in Real Time Planning and Search  

Microsoft Academic Search

Real time artificial intelligence (AI) systems are required to respond within a given deadline, or have optimal response times. While some researchers have addressed the issue of planning under deadline constraints, there has been very little research towards optimizing the response time of problem-solvi ng methods. The costs for a response consists of the cost to plan for a solution

Shashi Shekhar; Soumitra Dutta

1989-01-01

148

Timed State Space Analysis of Real-Time Preemptive Systems  

Microsoft Academic Search

Abstract: A modeling notation is introduced which extends Time Petri Nets with anadditional mechanism of resource assignment which makes the progress of timedtransitions be dependent on the availability of a set of preemptable resources. Theresulting notation, which we call Preemptive Time Petri Nets, permits naturaldescription of complex real time systems running under preemptive scheduling,with periodic, sporadic and one-shot processes, with

Giacomo Bucci; Andrea Fedeli; Luigi Sassoli; Enrico Vicario

2004-01-01

149

Specifying and verifying real-time systems using time Petri nets and real-time temporal logic  

Microsoft Academic Search

A method of integrating time predicate transition nets (a class of high-level Petri nets) and real-time first-order temporal logic is developed for specifying and verifying real-time systems. The integration of time predicate transition nets with real-time temporal logic is based on previous work (X. He and J.A.N. Lee, 1990) with the extension of time features so that not only concurrent

Xudong He

1991-01-01

150

A unified wireless LAN architecture for real-time and non-real-time communication services  

Microsoft Academic Search

This paper addresses how to support both real-time and non-real-time communication services in a wireless LAN with dynamic time-division duplexed (D-TDD) transmission. With D-TDD, a frequency channel is time-shared for both downlink and uplink transmissions under the dynamic access control of the base station. The base station 1) handles uplink transmissions by polling mobiles in certain order determined on a

Sunghyun Choi; Kang G. Shin

2000-01-01

151

Approach to real-time holography  

SciTech Connect

Various diagnostic procedures in medicine, industry and defense produce 3-Dimensional data bases adequate to calculate a hologram. In most cases the nearer to real time the hologram can be produced the more beneficial. Since a hologram is a superposition of Fresnel zone plate patterns from each point source in the object volume on to the image plane a cellular array processor is suggested which will produce a factor of a million reduction in the time to calculate a hologram.

Davidson, H.L.; Friedland, S.S.

1983-07-15

152

Real-time quantitative PCR in parasitology  

Microsoft Academic Search

Standard techniques for counting parasites are often time-consuming, difficult and inaccurate, and occasionally unpleasant. Real-time quantitative polymerase chain reaction has recently been applied to parasitology, specifically Plasmodium, Toxoplasma, Leishmania and Neospora. These techniques are truly quantitative, give results over a range of 6–7 orders of magnitude, are quick to perform and require no manipulations post-amplification. They can be used to

Andrew S. Bell; Lisa C. Ranford-Cartwright

2002-01-01

153

Selective Call Out and Real Time Bidding  

Microsoft Academic Search

Ads on the Internet are increasingly sold via ad exchanges such as\\u000aRightMedia, AdECN and Doubleclick Ad Exchange. These exchanges allow real-time\\u000abidding, that is, each time the publisher contacts the exchange, the exchange\\u000a``calls out'' to solicit bids from ad networks. This aspect of soliciting bids\\u000aintroduces a novel aspect, in contrast to existing literature. This suggests\\u000adeveloping a

Tanmoy Chakraborty; Eyal Even-Dar; Sudipto Guha; Yishay Mansour; S. Muthukrishnan

2010-01-01

154

Real-Time Streamflow Data via Satellite  

NSDL National Science Digital Library

The US Geological Survey's Water Resources division in Anchorage, Alaska provides these real-time data from stream flow gages at observation stations in Alaska's (USA) Arctic Slope, Northwest, Southwest, South Central, Southeast, and Yukon Basin regions. Note that the data may be subject to significant change and "are not citeable until reviewed and approved by the USGS." Data include Long-term median flow, Flow, Stage, Water Temperature, and Date/ Time.

155

Real Time RF Simulator (RTS) and control  

SciTech Connect

The multi-cavity RTS allows LLRF algorithm development and lab testing prior to commissioning with real cavities and cryomodules. The RTS is a valuable tool since it models the functions, errors and disturbances of real RF systems. The advantage of a RTS over an off-line simulator is that it can be implemented on the actual LLRF hardware, on the same FPGA and processor, and run at the same speed of the LLRF control loop. Additionally the RTS can be shared by collaborators who do not have access to RF systems or when the systems are not available to LLRF engineers. The RTS simulator incorporates hardware, firmware and software errors and limitations of a real implementation, which would be hard to identify and time consuming to model in off-line simulations.

Cancelo, G.; Armiento, C.; Treptow, K.; Vignoni, A.; Zmuda, T.; /Fermilab

2008-10-01

156

Real Time Pricing and the Real Live Firm  

SciTech Connect

Energy economists have long argued the benefits of real time pricing (RTP) of electricity. Their basis for modeling customers response to short-term fluctuations in electricity prices are based on theories of rational firm behavior, where management strives to minimize operating costs and optimize profit, and labor, capital and energy are potential substitutes in the firm's production function. How well do private firms and public sector institutions operating conditions, knowledge structures, decision-making practices, and external relationships comport with these assumptions and how might this impact price response? We discuss these issues on the basis of interviews with 29 large (over 2 MW) industrial, commercial, and institutional customers in the Niagara Mohawk Power Corporation service territory that have faced day-ahead electricity market prices since 1998. We look at stories interviewees told about why and how they respond to RTP, why some customers report that they can't, and why even if they can, they don't. Some firms respond as theorized, and we describe their load curtailment strategies. About half of our interviewees reported that they were unable to either shift or forego electricity consumption even when prices are high ($0.50/kWh). Reasons customers gave for why they weren't price-responsive include implicit value placed on reliability, pricing structures, lack of flexibility in adjusting production inputs, just-in-time practices, perceived barriers to onsite generation, and insufficient time. We draw these observations into a framework that could help refine economic theory of dynamic pricing by providing real-world descriptions of how firms behave and why.

Moezzi, Mithra; Goldman, Charles; Sezgen, Osman; Bharvirkar, Ranjit; Hopper, Nicole

2004-05-26

157

Real Time Correction of Aircraft Flight Fonfiguration  

NASA Technical Reports Server (NTRS)

Method and system for monitoring and analyzing, in real time, variation with time of an aircraft flight parameter. A time-dependent recovery band, defined by first and second recovery band boundaries that are spaced apart at at least one time point, is constructed for a selected flight parameter and for a selected time recovery time interval length .DELTA.t(FP;rec). A flight parameter, having a value FP(t=t.sub.p) at a time t=t.sub.p, is likely to be able to recover to a reference flight parameter value FP(t';ref), lying in a band of reference flight parameter values FP(t';ref;CB), within a time interval given by t.sub.p.ltoreq.t'.ltoreq.t.sub.p.DELTA.t(FP;rec), if (or only if) the flight parameter value lies between the first and second recovery band boundary traces.

Schipper, John F. (Inventor)

2009-01-01

158

Real time gamma-ray signature identifier  

DOEpatents

A real time gamma-ray signature/source identification method and system using principal components analysis (PCA) for transforming and substantially reducing one or more comprehensive spectral libraries of nuclear materials types and configurations into a corresponding concise representation/signature(s) representing and indexing each individual predetermined spectrum in principal component (PC) space, wherein an unknown gamma-ray signature may be compared against the representative signature to find a match or at least characterize the unknown signature from among all the entries in the library with a single regression or simple projection into the PC space, so as to substantially reduce processing time and computing resources and enable real-time characterization and/or identification.

Rowland, Mark (Alamo, CA); Gosnell, Tom B. (Moraga, CA); Ham, Cheryl (Livermore, CA); Perkins, Dwight (Livermore, CA); Wong, James (Dublin, CA)

2012-05-15

159

Temporal Uncertainties in Interactions among Real-Time Objects  

Microsoft Academic Search

A model of a distributed real-time system which supports reasoning about the consistency and accuracy of real-time data and about the performance of real-time communication protocols is presented. The conventional object model is extended into a model of a real-time (RT-) object which incorporates a real-time clock as a mechanism for initiating an object action as a function of real

Hermann Kopetz; K. H. Kim

1990-01-01

160

A Light Lock Management Mechanism for Optimizing Real-Time and Non-Real-Time Performance in Embedded Linux  

Microsoft Academic Search

In a real-time Linux system, the critical sections are known as the main factor delaying the execution of real-time tasks. Traditional approaches to overcoming this issue have given less consideration to both real-time and non-real-time tasks. In this paper, we propose a new lock management mechanism to improve the real-time performance with a small penalty for non-real-time tasks. Using this

Maobing Dai; Toshihiro Matsui; Yutaka Ishikawa

2008-01-01

161

Real-Time Seismology in Portugal  

NASA Astrophysics Data System (ADS)

Portugal is located next to the plate boundary between Eurasia (Iberia) and Africa (Nubia). The country has been repeatedly affected by some of the largest earthquakes, both onshore and offshore, in the historical European record, including the largest historical European earthquake, the great Lisbon earthquake of 1755 (~M8.5). The Portuguese territory has suffered directly the consequences of strong ground shaking (collapse of buildings, etc) and also some of the most destructive consequences of earthquakes (e.g. tsunamis, fires, etc). However, the rate of tectonic deformation in the Portuguese territory is low (the Eurasian-African plates converge at a rate of ~ 5 mm/yr), which results in long recurrence intervals between earthquakes. This low to moderate rate of seismic activity has two major negative effects: 1) it is difficult to study the regional seismo-tectonics with traditional passive methods; 2) the population is little aware of earthquake risk and unprepared to react in case of disaster. In this scenario, real-time seismology is key to monitoring earthquake crisis in real-time, providing early warnings about potentially destructive events, and assisting in the channeling of recovery efforts in case of disaster. In this paper we will present the real-time algorithms implemented at Instituto de Meteorologia (IM), the institution responsible for seismic monitoring in Portugal. In particular, we will focus on the following aspects: 1) Data collection and real-time transmission to the headquarters. Broadband seismological stations are owned and operated by five different institutions. The last years have witnessed an effort for integration, and presently most data arrives at IM lab in real-time. 2) Earthquake location and local magnitude determination. Data is automatically analyzed in order to obtain a first earthquake hypocenter and ML. While this process is mostly automatic, it still requires the revision by an operator, who is available 24h. 3) Production of maps of ground shaking. Shakemaps are automatically produced based on the incoming data. We have calibrated Shakemaps taking into account regional attenuation laws and site effects. We have also developed a new tool to assess the uncertainty in Shakemaps, by considering different attenuation laws and site conditions proposed in the literature. 4) Moment tensor inversion. We use two different algorithms to compute moment tensor, determine focal mechanism, and infer true rupture plane. One of the algorithms - KIWI - runs automatically, with no human intervention. The other - ISOLA - requires manual input and is used as a double check on the results obtained with KIWI. One of the next steps is to link the real-time seismic system with the tsunami early warning system.

Custodio, S.; Marreiros, C.; Carvalho, S.; Vales, D.; Lima, V.; Carrilho, F.

2012-12-01

162

Temporal logics and real time expert systems.  

PubMed

This paper introduces temporal logics. Due to the eternal compromise between expressive adequacy and reasoning efficiency that must decided upon in any application, full (first order logic or modal logic based) temporal logics are frequently not suitable. This is especially true in real time expert systems, where a fixed (and usually small) response time must be guaranteed. One such expert system, Fagan's VM, is reviewed, and a delineation is given of how to formally describe and reason with time in medical protocols. It is shown that Petri net theory is a useful tool to check the correctness of formalised protocols. PMID:8894390

Blom, J A

1996-10-01

163

Real-Time Imaging of Quantum Entanglement  

PubMed Central

Quantum Entanglement is widely regarded as one of the most prominent features of quantum mechanics and quantum information science. Although, photonic entanglement is routinely studied in many experiments nowadays, its signature has been out of the grasp for real-time imaging. Here we show that modern technology, namely triggered intensified charge coupled device (ICCD) cameras are fast and sensitive enough to image in real-time the effect of the measurement of one photon on its entangled partner. To quantitatively verify the non-classicality of the measurements we determine the detected photon number and error margin from the registered intensity image within a certain region. Additionally, the use of the ICCD camera allows us to demonstrate the high flexibility of the setup in creating any desired spatial-mode entanglement, which suggests as well that visual imaging in quantum optics not only provides a better intuitive understanding of entanglement but will improve applications of quantum science.

Fickler, Robert; Krenn, Mario; Lapkiewicz, Radek; Ramelow, Sven; Zeilinger, Anton

2013-01-01

164

CIESE Real Time Data Projects: Tsunami Surge  

NSDL National Science Digital Library

This internet-based project for Grades 6-12 taps into real-time data as the framework for a student investigation of tsunami phenomena. First, students look at historical information on five tsunamis, then interactively explore the science behind tsunamis and wave behavior. Next, students will access and interpret existing data from the highly destructive 2004 Indian Ocean tsunami. Finally, students take on roles as scientists to develop a global tsunami preparedness plan based on a budget. They must support their ideas with evidence from reliable data and present arguments based upon their studies. Included are detailed project instructions, teacher's guide, reference material, and a student discussion forum. This project is part of the CIESE K-12 Curriculum Program's Real Time Data Projects. See Related Materials for a link to the full index of data projects.

2012-04-14

165

Distributed Real-Time Computing with Harness  

SciTech Connect

Modern parallel and distributed computing solutions are often built onto a ''middleware'' software layer providing a higher and common level of service between computational nodes. Harness is an adaptable, plugin-based middleware framework for parallel and distributed computing. This paper reports recent research and development results of using Harness for real-time distributed computing applications in the context of an industrial environment with the needs to perform several safety critical tasks. The presented work exploits the modular architecture of Harness in conjunction with a lightweight threaded implementation to resolve several real-time issues by adding three new Harness plug-ins to provide a prioritized lightweight execution environment, low latency communication facilities, and local timestamped event logging.

Di Saverio, Emanuele [University of Rome 'Tor Vergata', Rome, Italy; Cesati, Marco [University of Rome 'Tor Vergata', Rome, Italy; Di Biagio, Christian [MBDA Italia SPA, Rome, Italy; Pennella, Guido [MBDA Italia SPA, Rome, Italy; Engelmann, Christian [ORNL

2007-01-01

166

Real-time remote scientific model validation  

NASA Technical Reports Server (NTRS)

This paper describes flight results from the use of a CLIPS-based validation facility to compare analyzed data from a space life sciences (SLS) experiment to an investigator's preflight model. The comparison, performed in real-time, either confirms or refutes the model and its predictions. This result then becomes the basis for continuing or modifying the investigator's experiment protocol. Typically, neither the astronaut crew in Spacelab nor the ground-based investigator team are able to react to their experiment data in real time. This facility, part of a larger science advisor system called Principal Investigator in a Box, was flown on the space shuttle in October, 1993. The software system aided the conduct of a human vestibular physiology experiment and was able to outperform humans in the tasks of data integrity assurance, data analysis, and scientific model validation. Of twelve preflight hypotheses associated with investigator's model, seven were confirmed and five were rejected or compromised.

Frainier, Richard; Groleau, Nicolas

1994-01-01

167

Real-time fingerprint verification system.  

PubMed

Access to security spaces and the verification of credit cards require, ideally, a simple and inexpensive system that combines accuracy with a high resistance to compromise. We have been investigating such a system. This system incorporates a novel fingerprint input arrangement that permits the use of optical pattern recognition for fingerprint verification in real time. Test results together with design considerations are reported. PMID:20720661

Gamble, F T; Frye, L M; Grieser, D R

1992-02-10

168

The history of real time ultrasound  

Microsoft Academic Search

This paper deals with real time two-dimensional ultrasonic imaging. In the early 1960s, one of the most important applications of ultrasound was to the brain. With the A-scan, the main aim was to detect any midline shift, in order to determine some space occupying object. Any other echo was usually difficult to recognize. Manual or mechanical scanning turned out to

Jan C. Somer

2004-01-01

169

Towards real-time dynamic spectrum auctions  

Microsoft Academic Search

In this paper, we propose a low-complexity auction framework to distribute spectrum in real-time among a large number of wireless users with dynamic traffic. Our design consists of a compact and highly-expressive bidding format, two pricing models to control tradeoffs between revenue and fairness, and fast auction clearing algorithms to achieve conflict-free spectrum allocations that maximize auction revenue. We develop

Sorabh Gandhi; Chiranjeeb Buragohain; Lili Cao; Haitao Zheng; Subhash Suri

2008-01-01

170

Real-Time Classification of Traffic Signs  

Microsoft Academic Search

A challenging real-time imaging problem is classifying video traffic signs in background clutter under rotation, scale, and translation invariant conditions. Normalized Gabor Wavelet Transform features from multi-resolution filters were originally biologically-based; however, optimized features proved more effective. Two whole image template matching techniques were unsuccessful. A statistical pattern recognition system recognized approximately 30% of the images for the original features

Phil Douville

2000-01-01

171

REAL-TIME COMMUNICATION IN AN INTERNETWORK  

Microsoft Academic Search

Can end-to-end communication performance be guaranteed by a packet-switching internetwork? This paper addresses the question by examining the feasibility of extending to an internetwork the Tenet approach to real-time communication service design. The conditions to be satisfied by an internetwork so that the approach can be extended to it are investigated. These include conditions for the scheduling discip- line to

Domenico Ferrari

1992-01-01

172

Real-Time Regularized Ultrasound Elastography  

Microsoft Academic Search

This paper introduces two real-time elastography techniques based on analytic minimization (AM) of regularized cost functions. The first method (1D AM) produces axial strain and integer lateral displacement, while the second method (2D AM) produces both axial and lateral strains. The cost functions incorporate similarity of radio-frequency (RF) data intensity and displacement continuity, making both AM methods robust to small

Hassan Rivaz; Emad M. Boctor; Michael A. Choti; Gregory D. Hager

2011-01-01

173

REAL TIME BETATRON TUNE CONTROL IN RHIC.  

SciTech Connect

Precise control of the betatron tunes is necessary to preserve proton polarization during the RHIC ramp. In addition, control of the tunes during beam deceleration is necessary due to hysteresis in the superconducting magnets. A real-time feedback system to control the betatron tunes during ramping has been developed for use in RHIC. This paper describes this system and presents the results from commissioning the system during the polarized proton run.

SCHULTHEISS,C.; CAMERON,P.; MARUSIC,A.; VAN ZEIJTS,J.

2002-06-02

174

Activation instanton in real-time formalism  

NASA Astrophysics Data System (ADS)

In this paper, we study the dynamics of the activation of a Brownian particle using the path integral formalism in real time. Along with the construction of the saddle-point (instanton) solutions, we develop the formalism allowing to calculate the effect of the fluctuations near this solution in detail. In particular, it is shown that there is a soft mode for which the integration is not Gaussian and just this mode is responsible for the finite probability flux.

Kolokolov, I. V.; Trung, Nguyen Thanh

2014-06-01

175

Dynamic Real-Time Optimistic Concurrency Control  

Microsoft Academic Search

In a recent study, we have shown that in real-time database systems that discard late transactions, optimistic concurrency control outperforms locking. Although the optimistic algorithm used in that study, OPT-BC, did not factor in transaction dead- lines in making data conflict resolution decisions, it still outper- formed a deadline-cognizant locking algorithm. In this paper, we discuss why adding deadline information

Jayant R. Haritsa; Michael J. Carey; Miron Livny

1990-01-01

176

Real-Time Clinical Monitoring of Biomolecules  

NASA Astrophysics Data System (ADS)

Continuous monitoring of clinical biomarkers offers the exciting possibility of new therapies that use biomarker levels to guide treatment in real time. This review explores recent progress toward this goal. We initially consider measurements in body fluids by a range of analytical methods. We then discuss direct tissue measurements performed by implanted sensors; sampling techniques, including microdialysis and ultrafiltration; and noninvasive methods. A future directions section considers analytical methods at the cusp of clinical use.

Rogers, Michelle L.; Boutelle, Martyn G.

2013-06-01

177

Real-Time X-Ray Inspection  

NASA Technical Reports Server (NTRS)

X-ray imaging instrument adapted to continuous scanning. Modern version of fluoroscope enables rapid x-ray inspection of parts. Developed for detection of buckling in insulated ducts. Uses radiation from radioactive gadolinium or thallium source. Instrument weighs only 6 1/2 lb. Quickly scanned by hand along duct surface, providing real-time image. Based on Lixiscope, developed at Goddard Space Flight Center.

Bulthuis, Ronald V.

1988-01-01

178

A real-time ISEE data system  

NASA Technical Reports Server (NTRS)

A real time International Sun Earth Explorer (ISEE) data system directed toward the prediction of geomagnetic substorms and storms is discussed in detail. Such a system may allow up to 60 minutes or more, advance warning of magnetospheric substorms and up to 30 minute warnings of geomagnetic storms induced by high speed streams and solar flares. The proposed system utilizes existing capabilities of several agencies thereby minimizing costs.

Tsurutani, B. T.; Baker, D. N.

1979-01-01

179

Real-time radiographic inspection facility  

NASA Technical Reports Server (NTRS)

A real time radiographic inspection facility has been developed for nondestructive evaluation applications. It consists of an X-ray source, an X-ray sensitive television imaging system, an electronic analog image processing system, and a digital image processing system. The digital image processing system is composed of a computer with the necessary software to drive the overall facility. Descriptions are given of the design strategy, the facility's components, and its current capabilities.

Roberts, E., Jr.

1977-01-01

180

Real-time fluorescence detection of exoribonucleases.  

PubMed

The identification of RNases or RNase effectors is a continuous challenge, particularly given the current importance of RNAs in the control of genome expression. Here, we show that a fluorogenic RNA-DNA hybrid is a powerful tool for a real-time fluorescence detection and assay of exoribonucleases (RT-FeDEx). This RT-FeDEx assay provides a new strategy for the isolation, purification, and assay of known and unknown exoribonucleases. PMID:19767421

Sinturel, Flore; Pellegrini, Olivier; Xiang, Song; Tong, Liang; Condon, Ciarán; Bénard, Lionel

2009-11-01

181

REAL TIME SUBMICRON THERMAL IMAGING USING THERMOREFLECTANCE  

Microsoft Academic Search

Thermal measurements on a sub-micron scale are non-trivial, but are important for the characterization of modern semiconductor and opto-electronic devices. In this paper we will discuss the application of the thermoreflectance method for real time sub-micron thermal imaging. By using light in the visible spectrum, the diffraction limit, and thus spatial resolution is improved over a traditional infrared camera based

James Christofferson; Daryoosh Vashaee; Philip Melese

182

Real-time speckle photography: a breakthrough  

NASA Astrophysics Data System (ADS)

Speckle photography for small displacements can be carried out rather easily. It is a well established method. Unfortunately problems arise when specklegrams must be obtained in real time. Silver halide media infer lengthy multi-stage photoprocessing of specklegrams. Real time speckle photography utilizing non-silver media can be implemented but the techniques involved are rather complicated. Extremely simple and inexpensive approaches to speckle photography are introduced here. They combine positive features of speckle photography and momental holography. This permits the user to produce quasi real time specklegrams within a few seconds. High quality speckle photographs were obtained with different laser sources on high resolution silver halide media: Russian PFG-03, PFG-03 C (color), Agfa-Gevaert 8E 75 HD films and plates. Very good specklegrams were obtained also in lighted environment. Hybrid holospecklegrams i.e. holograms and speckle photographs of the same object were obtained simultaneously on the same media. Such holospecklegrams were also produced within fa few seconds. Quite unexpectedly good specklegrams were recorded even in water. Photographs of momentally produced specklegrams are given.

Petrov, Valery

1996-12-01

183

The IGS Real-Time Service  

NASA Astrophysics Data System (ADS)

The IGS Real-Time Service (RTS) is being rolled out in 2013 following the successful completion of the IGS Real-Time Pilot Project. The RTS has recently completed beta testing and is now operating at the level of initial operating capability. The service will reach full operating capability by the end of 2013. RTS products include GNSS data streams and GNSS orbit and clock correction streams. These products are available in real-time in accordance with the IGS open-data policy using RTCM standard formats and the NTRIP transportation protocol. The RTS is key to IGS's support of the GGOS Natural Hazards theme. Of particular importance in this context is the high degree of redundancy that is build into the RTS in order to reliably support public-good scientific applications commonly associated with natural hazards; for example, precise-point positioning applications requiring high accuracy and low latency related to earthquakes and tsunamis . This presentation will illustrate the data gathering through product generation to user distribution design of the RTS, highlighting built-in robustness at various stages. The presentation will also present an assessment of the performance of the service to date.

Caissy, Mark; Agrotis, Loukis; Weber, Georg; Fisher, Steven

2013-04-01

184

Real-time optical image processing techniques  

NASA Technical Reports Server (NTRS)

Nonlinear real-time optical processing on spatial pulse frequency modulation has been pursued through the analysis, design, and fabrication of pulse frequency modulated halftone screens and the modification of micro-channel spatial light modulators (MSLMs). Micro-channel spatial light modulators are modified via the Fabry-Perot method to achieve the high gamma operation required for non-linear operation. Real-time nonlinear processing was performed using the halftone screen and MSLM. The experiments showed the effectiveness of the thresholding and also showed the needs of higher SBP for image processing. The Hughes LCLV has been characterized and found to yield high gamma (about 1.7) when operated in low frequency and low bias mode. Cascading of two LCLVs should also provide enough gamma for nonlinear processing. In this case, the SBP of the LCLV is sufficient but the uniformity of the LCLV needs improvement. These include image correlation, computer generation of holograms, pseudo-color image encoding for image enhancement, and associative-retrieval in neural processing. The discovery of the only known optical method for dynamic range compression of an input image in real-time by using GaAs photorefractive crystals is reported. Finally, a new architecture for non-linear multiple sensory, neural processing has been suggested.

Liu, Hua-Kuang

1988-01-01

185

Software Analyzes Complex Systems in Real Time  

NASA Technical Reports Server (NTRS)

Expert system software programs, also known as knowledge-based systems, are computer programs that emulate the knowledge and analytical skills of one or more human experts, related to a specific subject. SHINE (Spacecraft Health Inference Engine) is one such program, a software inference engine (expert system) designed by NASA for the purpose of monitoring, analyzing, and diagnosing both real-time and non-real-time systems. It was developed to meet many of the Agency s demanding and rigorous artificial intelligence goals for current and future needs. NASA developed the sophisticated and reusable software based on the experience and requirements of its Jet Propulsion Laboratory s (JPL) Artificial Intelligence Research Group in developing expert systems for space flight operations specifically, the diagnosis of spacecraft health. It was designed to be efficient enough to operate in demanding real time and in limited hardware environments, and to be utilized by non-expert systems applications written in conventional programming languages. The technology is currently used in several ongoing NASA applications, including the Mars Exploration Rovers and the Spacecraft Health Automatic Reasoning Pilot (SHARP) program for the diagnosis of telecommunication anomalies during the Neptune Voyager Encounter. It is also finding applications outside of the Space Agency.

2008-01-01

186

Acting to gain information: Real-time reasoning meets real-time perception  

NASA Technical Reports Server (NTRS)

Recent advances in intelligent reactive systems suggest new approaches to the problem of deriving task-relevant information from perceptual systems in real time. The author will describe work in progress aimed at coupling intelligent control mechanisms to real-time perception systems, with special emphasis on frame rate visual measurement systems. A model for integrated reasoning and perception will be discussed, and recent progress in applying these ideas to problems of sensor utilization for efficient recognition and tracking will be described.

Rosenschein, Stan

1994-01-01

187

Real-time synthetic aperture radar processing  

NASA Technical Reports Server (NTRS)

Real-time acousto-optic SAR processors are described and experimentally demonstrated. SAR imaging is performed in one of the architectures by applying the signal to an acousto-optic device and correlating it with chirp signals recorded on an optical transparency by time integration on a CCD detector. In a different implementation, the imaging is preformed by interfering the light beams diffracted from two separate acousto-optic devices, one modulated the radar signal and the second by the reference chirp waveform.

Psaltis, D.; Haney, M.; Wagner, K.

1984-01-01

188

Real-Time Rendering of Real-World Environments  

Microsoft Academic Search

One of the most important goals of interactive computer graphics is to allow a user to freely walk around a virtual recreation of a real environment that looks as real as the world around us. But hand-modeling such a virtual environment is inherently limited and acquiring the scene model using devices also presents challenges. Interactively rendering such a detailed model

David K. Mcallister; Lars S. Nyland; Voicu Popescu; Anselmo Lastra; Chris Mccue

1999-01-01

189

REAL-TIME TIME-FREQUENCY BASED BLIND SOURCE SEPARATION  

Microsoft Academic Search

We present a real-time version of the DUET algorithm for the blind separation of any number of sources using only two mixtures. The method applies when sources are W- disjoint orthogonal, that is, when the supports of the win- dowed Fourier transform of any two signals in the mixture are disjoint sets, an assumption which is justified in the Ap-

Scott Rickard; Radu Balan; Justinian Rosca

2001-01-01

190

Finding Response Times in a Real-Time System  

Microsoft Academic Search

There are two major performance issues in a real-time system where a processor has a set of devices connected to it at different priority levels. The first is to prove whether, for a given assignment of devices to priority levels, the system can handle its peak processing load without losing any inputs from the devices. The second is to determine

Mathai Joseph; Paritosh K. Pandya

1986-01-01

191

Exploring Earthquakes in Real-Time  

NASA Astrophysics Data System (ADS)

Earthquakes capture the attention of students and inspire them to explore the Earth. Adding the ability to view and explore recordings of significant and newsworthy earthquakes in real-time makes the subject even more compelling. To address this opportunity, the Incorporated Research Institutions for Seismology (IRIS), in collaboration with Moravian College, developed ';jAmaSeis', a cross-platform application that enables students to access real-time earthquake waveform data. Students can watch as the seismic waves are recorded on their computer, and can be among the first to analyze the data from an earthquake. jAmaSeis facilitates student centered investigations of seismological concepts using either a low-cost educational seismograph or streamed data from other educational seismographs or from any seismic station that sends data to the IRIS Data Management System. After an earthquake, students can analyze the seismograms to determine characteristics of earthquakes such as time of occurrence, distance from the epicenter to the station, magnitude, and location. The software has been designed to provide graphical clues to guide students in the analysis and assist in their interpretations. Since jAmaSeis can simultaneously record up to three stations from anywhere on the planet, there are numerous opportunities for student driven investigations. For example, students can explore differences in the seismograms from different distances from an earthquake and compare waveforms from different azimuthal directions. Students can simultaneously monitor seismicity at a tectonic plate boundary and in the middle of the plate regardless of their school location. This can help students discover for themselves the ideas underlying seismic wave propagation, regional earthquake hazards, magnitude-frequency relationships, and the details of plate tectonics. The real-time nature of the data keeps the investigations dynamic, and offers students countless opportunities to explore.

Bravo, T. K.; Kafka, A. L.; Coleman, B.; Taber, J. J.

2013-12-01

192

Real-time Interplanetary Shock Prediciton System  

NASA Astrophysics Data System (ADS)

A system is being developed to predict the arrival times and maximum intensities of energetic storm particle (ESP) events at the earth. Measurements of particle flux values at L1 being made by the Electron, Proton, and Alpha Monitor (EPAM) instrument aboard NASA's ACE spacecraft are made available in real-time by the NOAA Space Environment Center as 5 minute averages of several proton and electron energy channels. Past EPAM flux measurements can be used to train forecasting algorithms which then run on the real-time data. Up to 3 days before the arrival of the interplanetary shock associated with an ESP event, characteristic changes in the particle intensities (such as decreased spectral slope and increased overall flux level) are easily discernable. Once the onset of an event is detected, a neural net is used to forecast the arrival time and flux level for the event. We present results obtained with this technique for forecasting the largest of the ESP events detected by EPAM. Forecasting information will be made publicly available through http://sd-www.jhuapl.edu/ACE/EPAM/, the Johns Hopkins University Applied Physics Lab web site for the ACE/EPAM instrument.

Vandegriff, J.; Ho, G.; Plauger, J.

193

Real-time design with peer tasks  

NASA Technical Reports Server (NTRS)

We introduce a real-time design methodology for large scale, distributed, parallel architecture, real-time systems (LDPARTS), as an alternative to those methods using rate or dead-line monotonic analysis. In our method the fundamental units of prioritization, work items, are domain specific objects with timing requirements (deadlines) found in user's specification. A work item consists of a collection of tasks of equal priority. Current scheduling theories are applied with artifact deadlines introduced by the designer whereas our method schedules work items to meet user's specification deadlines (sometimes called end-to-end deadlines). Our method supports these scheduling properties. Work item scheduling is based on domain specific importance instead of task level urgency and still meets as many user specification deadlines as can be met by scheduling tasks with respect to urgency. Second, the minimum (closest) on-line deadline that can be guaranteed for a work item of highest importance, scheduled at run time, is approximately the inverse of the throughput, measured in work items per second. Third, throughput is not degraded during overload and instead of resorting to task shedding during overload, the designer can specify which work items to shed. We prove these properties in a mathematical model.

Goforth, Andre; Howes, Norman R.; Wood, Jonathan D.; Barnes, Michael J.

1995-01-01

194

Real-time computed optical interferometric tomography  

NASA Astrophysics Data System (ADS)

High-resolution tomography is of great importance to many areas of biomedical imaging, but with it comes several apparent tradeoffs such as a narrowing depth-of-field and increasing optical aberrations. Overcoming these challenges has attracted many hardware and computational solutions. Hardware solutions, though, can become bulky or expensive and computational approaches can require high computing power or large processing times. This study demonstrates memory efficient implementations of interferometric synthetic aperture microscopy (ISAM) and computational adaptive optics (CAO) - two computational approaches for overcoming the depthof- field limitation and the effect of optical aberrations in optical coherence tomography (OCT). Traditionally requiring lengthy post processing, here we report implementations of ISAM and CAO on a single GPU for real-time in vivo imaging. Real-time, camera-limited ISAM processing enabled reliable acquisition of stable data for in vivo imaging, and CAO processing on the same GPU is shown to quickly correct static aberrations. These algorithmic advances hold the promise for high-resolution volumetric imaging in time-sensitive situations as well as enabling aberrationfree cellular-level volumetric tomography.

Shemonski, Nathan D.; Liu, Yuan-Zhi; Ahmad, Adeel; Adie, Steven G.; Carney, P. Scott; Boppart, Stephen A.

2014-03-01

195

Real-Time Flight Envelope Monitoring System  

NASA Technical Reports Server (NTRS)

The objective of this effort was to show that real-time aircraft control-surface hinge-moment information could be used to provide a robust and reliable prediction of vehicle performance and control authority degradation. For a given airfoil section with a control surface -- be it a wing with an aileron, rudder, or elevator -- the control-surface hinge moment is sensitive to the aerodynamic characteristics of the section. As a result, changes in the aerodynamics of the section due to angle-of-attack or environmental effects such as icing, heavy rain, surface contaminants, bird strikes, or battle damage will affect the control surface hinge moment. These changes include both the magnitude of the hinge moment and its sign in a time-averaged sense, and the variation of the hinge moment with time. The current program attempts to take the real-time hinge moment information from the aircraft control surfaces and develop a system to predict aircraft envelope boundaries across a range of conditions, alerting the flight crew to reductions in aircraft controllability and flight boundaries.

Kerho, Michael; Bragg, Michael B.; Ansell, Phillip J.

2012-01-01

196

A Self-Timed Real-Time Sorting Network  

Microsoft Academic Search

High speed networks are expected to carry traffic classes with diverse Quality of Service (QoS) guarantees. For efficient utiliza- tion of resources, sophisticated scheduling protocols are needed; however, these must be implemented without sacrificing the max- imum possible bandwidth. This paper presents the architec- ture and implementation of a self-timed real-time sorting net- work to be used in packet switches

Kenneth Y. Yun; Supratik Chakraborty; Kevin W. James

197

A self-timed real-time sorting network  

Microsoft Academic Search

High speed networks are expected to carry traffic classes wit h diverse Quality of Service (QoS) guarantees. For efficient u tiliza- tion of resources, sophisticated scheduling protocols areneeded; however, these must be implemented without sacrificing the m ax- imum possible bandwidth. This paper presents the architec- ture and implementation of a self-timed real-time sorting net- work to be used in

Kenneth Y. Yun; Kevin W. James; Robert H. Fairlie-Cuninghame; Supratik Chakraborty; Rene L. Cruz

2000-01-01

198

Real-time Interplanetary Shock Prediction System  

NASA Astrophysics Data System (ADS)

We are creating a system to predict the arrival times and maximum intensities of energetic storm particle (ESP) events at the earth using particle fluxes measured by the EPAM instrument aboard NASA's ACE spacecraft. Real-time flux measurements, consisting of 5 minute averages made available 24 hours per day by the NOAA Space Environment Center, are fed into algorithms looking for characteristic changes in flux, velocity dispersion, and anisotropy. These quantities typically show changes up to 3 hours before shock passage, and thus we expect our system to deliver enhanced probabilities for shock arrival with approximately the same lead time. Forecasting information will be made publicly available through http://sd-www.jhuapl.edu/ACE/EPAM/, the Johns Hopkins University Applied Physics Lab web site for the ACE/EPAM instrument. Early results on the training of our algorithms and comparisons with past shock data will be presented.

Vandegriff, J. D.; Ho, G. C.; Plauger, J. M.

2002-05-01

199

Real Time Simulation of Power Grid Disruptions  

SciTech Connect

DOE-OE and DOE-SC workshops (Reference 1-3) identified the key power grid problem that requires insight addressable by the next generation of exascale computing is coupling of real-time data streams (1-2 TB per hour) as the streams are ingested to dynamic models. These models would then identify predicted disruptions in time (2-4 seconds) to trigger the smart grid s self healing functions. This project attempted to establish the feasibility of this approach and defined the scientific issues, and demonstrated example solutions to important smart grid simulation problems. These objectives were accomplished by 1) using the existing frequency recorders on the national grid to establish a representative and scalable real-time data stream; 2) invoking ORNL signature identification algorithms; 3) modeling dynamically a representative region of the Eastern interconnect using an institutional cluster, measuring the scalability and computational benchmarks for a national capability; and 4) constructing a prototype simulation for the system s concept of smart grid deployment. The delivered ORNL enduring capability included: 1) data processing and simulation metrics to design a national capability justifying exascale applications; 2) Software and intellectual property built around the example solutions; 3) demonstrated dynamic models to design few second self-healing.

Chinthavali, Supriya [ORNL; Dimitrovski, Aleksandar D [ORNL; Fernandez, Steven J [ORNL; Groer, Christopher S [ORNL; Nutaro, James J [ORNL; Olama, Mohammed M [ORNL; Omitaomu, Olufemi A [ORNL; Shankar, Mallikarjun [ORNL; Spafford, Kyle L [ORNL; Vacaliuc, Bogdan [ORNL

2012-11-01

200

Real-time applications of neural nets  

SciTech Connect

Producing, accelerating and colliding very high power, low emittance beams for long periods is a formidable problem in real-time control. As energy has grown exponentially in time so has the complexity of the machines and their control systems. Similar growth rates have occurred in many areas, e.g., improved integrated circuits have been paid for with comparable increases in complexity. However, in this case, reliability, capability and cost have improved due to reduced size, high production and increased integration which allow various kinds of feedback. In contrast, most large complex systems (LCS) are perceived to lack such possibilities because only one copy is made. Neural nets, as a metaphor for LCS, suggest ways to circumvent such limitations. It is argued that they are logically equivalent to multi-loop feedback/forward control of faulty systems. While complimentary to AI, they mesh nicely with characteristics desired for real-time systems. Such issues are considered, examples given and possibilities discussed. 21 refs., 6 figs.

Spencer, J.E.

1989-05-01

201

Real-time PCR in microfluidic devices  

NASA Astrophysics Data System (ADS)

A central method in a standard biochemical laboratory is represented by the polymerase chain reaction (PCR), therefore many attempts have been performed so far to implement this technique in lab-on-a-chip (LOC) devices. PCR is an ideal candidate for miniaturization because of a reduction of assay time and decreased costs for expensive bio-chemicals. In case of the "classical" PCR, detection is done by identification of DNA fragments electrophoretically separated in agarose gels. This method is meanwhile frequently replaced by the so-called Real-Time-PCR because here the exponential increase of amplificates can be observed directly by measurement of DNA interacting fluorescent dyes. Two main methods for on-chip PCRs are available: traditional "batch" PCR in chambers on a chip using thermal cycling, requiring about 30 minutes for a typical PCR protocol and continuous-flow PCR, where the liquid is guided over stationary temperature zones. In the latter case, the PCR protocol can be as fast as 5 minutes. In the presented work, a proof of concept is demonstrated for a real-time-detection of PCR products in microfluidic systems.

Becker, Holger; Hlawatsch, Nadine; Klemm, Richard; Moche, Christian; Hansen-Hagge, Thomas; Gärtner, Claudia

2014-03-01

202

Real-time failure control (SAFD)  

NASA Technical Reports Server (NTRS)

The Real Time Failure Control program involves development of a failure detection algorithm, referred as System for Failure and Anomaly Detection (SAFD), for the Space Shuttle Main Engine (SSME). This failure detection approach is signal-based and it entails monitoring SSME measurement signals based on predetermined and computed mean values and standard deviations. Twenty four engine measurements are included in the algorithm and provisions are made to add more parameters if needed. Six major sections of research are presented: (1) SAFD algorithm development; (2) SAFD simulations; (3) Digital Transient Model failure simulation; (4) closed-loop simulation; (5) SAFD current limitations; and (6) enhancements planned for.

Panossian, Hagop V.; Kemp, Victoria R.; Eckerling, Sherry J.

1990-01-01

203

Open Source Real Time Operating Systems Overview  

SciTech Connect

Modern control systems applications are often built on top of a real time operating system (RTOS) which provides the necessary hardware abstraction as well as scheduling, networking and other services. Several open source RTOS solutions are publicly available, which is very attractive, both from an economic (no licensing fees) as well as from a technical (control over the source code) point of view. This contribution gives an overview of the RTLinux and RTEMS systems (architecture, development environment, API etc.). Both systems feature most popular CPUs, several APIs (including Posix), networking, portability and optional commercial support. Some performance figures are presented, focusing on interrupt latency and context switching delay.

Straumann, Till

2001-12-11

204

Real-time teleteaching in medical physics.  

PubMed

Medical physics is a relatively small professional community, usually with a scarcity of expertise that could greatly benefit students entering the field. However, the reach of the profession can span great geographical distances, making the training of students a difficult task. In addition to the requirement of training new students, the evolving field of medical physics, with its many emerging advanced techniques and technologies, could benefit greatly from ongoing continuing education as well as consultation with experts.Many continuing education courses and workshops are constantly being offered, including many web-based study courses and virtual libraries. However, one mode of education and communication that has not been widely used is the real-time interactive process. Video-based conferencing systems do exist, but these usually require a substantial amount of effort and cost to set up.The authors have been working on promoting the ever-expanding capability of the Internet to facilitate the education of medical physics to students entering the field. A pilot project has been carried out for six years and reported previously. The project is a collaboration between the Department of Medical Physics at the Toronto Odette Cancer Centre in Canada and the Department of Biomedical Imaging at the University of Malaya in Malaysia. Since 2001, medical physics graduate students at the University of Malaya have been taught by lecturers from Toronto every year, using the Internet as the main tool of communication.The pilot study explored the different methods that can be used to provide real-time interactive remote education, and delivered traditional classroom lectures as well as hands-on workshops.Another similar project was started in 2007 to offer real-time teaching to a class of medical physics students at Wuhan University in Hubei, China. There are new challenges as well as new opportunities associated with this project. By building an inventory of tools and experiences, the intent is to broaden the real-time teleteaching method to serve a wide community so that future students entering the field can have efficient access to high-quality education that will benefit the profession in the long term. PMID:21614306

Woo, M; Ng, Kh

2008-01-01

205

Simultaneous real-time data collection methods  

NASA Technical Reports Server (NTRS)

This paper describes the development of electronic test equipment which executes, supervises, and reports on various tests. This validation process uses computers to analyze test results and report conclusions. The test equipment consists of an electronics component and the data collection and reporting unit. The PC software, display screens, and real-time data-base are described. Pass-fail procedures and data replay are discussed. The OS2 operating system and Presentation Manager user interface system were used to create a highly interactive automated system. The system outputs are hardcopy printouts and MS DOS format files which may be used as input for other PC programs.

Klincsek, Thomas

1992-01-01

206

General purpose computers in real time  

SciTech Connect

I see three main trends in the use of general purpose computers in real time. The first is more processing power. The second is the use of higher speed interconnects between computers (allowing more data to be delivered to the processors). The third is the use of larger programs running in the computers. Although there is still work that needs to be done, I believe that all indications are that the online need for general purpose computers should be available for the SCC and LHC machines. 2 figs.

Biel, J.R.

1989-09-18

207

Real-Time Surface Traffic Adviser  

NASA Technical Reports Server (NTRS)

A real-time data management system which uses data generated at different rates by multiple heterogeneous incompatible data sources are presented. In one embodiment, the invention is as an airport surface traffic data management system (traffic adviser) that electronically interconnects air traffic control, airline, and airport operations user communities to facilitate information sharing and improve taxi queuing. The system uses an expert system to fuse dam from a variety of airline, airport operations, ramp control, and air traffic control sources, in order to establish, predict, and update reference data values for every aircraft surface operation.

Glass, Brian J. (Inventor); Spirkovska, Liljana (Inventor); McDermott, William J. (Inventor); Reisman, Ronald J. (Inventor); Gibson, James (Inventor); Iverson, David L. (Inventor)

2001-01-01

208

Real-Time Optimization Of Receiver Bandwidth  

NASA Technical Reports Server (NTRS)

Estimates of signal and noise spectra enhance reception of weak signals. Carrier-tracking phase-locked loop represented by linear mathematical model at small rms phase errors. Loop continuously generates estimates of received phase. Bandwidth (in effect, scale of complex-frequency variable p) optimized to minimize rms phase error. Minimum signals tracked 5 to 15 dB below those tracked by current receivers. Improvement accomplished by use of bandwidths of 0.1 to 1.0 Hz, in contrast with 3-Hz bandwidth in current use. Principle of real-time optimization of bandwidth adapted to other situations to enhance reception of weak signals otherwise "buried" in noise.

Vilnrotter, V. A.; Hurd, W. J.; Brown, D. H.

1989-01-01

209

Real-time radar rainfall estimation  

NASA Astrophysics Data System (ADS)

This research reports on several aspects of real-time monitoring of the spatial and temporal distribution of rainfall from ground-based weather radar. Optimization of the performance of the National Weather Service's Precipitation Processing Subsystem (PPS) is the first objective. This is achieved by developing a calibration procedure which simultaneously estimates the optimal parameter values by providing a global assessment of the system's performance. Evaluation of the system is based on a data set consisting of two months of radar reflectivity measurements, and hourly raingage rainfall accumulations, from the Melbourne, Florida WSR-88D site. Radar-raingage root mean square (RMS) difference reduction up to 20% with respect to the default system parameter values is demonstrated. Investigation of statistical procedures for real-time adjustment of the mean-field systematic radar rainfall error is the second objective. For this purpose, a data- based Monte Carlo simulation experiment is performed. The study uses an extensive data set of hourly radar rainfall products and raingage accumulations from the Tulsa, Oklahoma WSR-88D site. This intercomparison study concluded to a bias procedure which overall appeared to perform better than the other. The main results from this research are: (1) statistical methods with optimal error model parameters perform significantly better than using only bias observations, and (2) bias adjustment is mostly effective in cold season precipitation measurements. Final objective of this research is development of a new real-time radar rainfall estimation algorithm. The new processing steps introduced in this algorithm are beam- height effect correction, vertical integration, rain classification, and continuous range effect correction. Additionally, the algorithm applies advection correction at the gridded rainfall rates to minimize the temporal sampling effect, and its calibration is cast in a recursive formulation with parameters adjusted in real- time. A new statistical method has been developed for quantification of radar rainfall products uncertainty. Evaluation of the system and the uncertainty quantification method is based on the data set from Melbourne, Florida WSR-88D site. Radar-raingage RMS difference reduction up to 50% with respect to the default PPS is demonstrated for the proposed algorithm.

Anagnostou, Emmanouil Nikolaos

1997-08-01

210

Systems Analyze Water Quality in Real Time  

NASA Technical Reports Server (NTRS)

A water analyzer developed under Small Business Innovation Research (SBIR) contracts with Kennedy Space Center now monitors treatment processes at water and wastewater facilities around the world. Originally designed to provide real-time detection of nutrient levels in hydroponic solutions for growing plants in space, the ChemScan analyzer, produced by ASA Analytics Inc., of Waukesha, Wisconsin, utilizes spectrometry and chemometric algorithms to automatically analyze multiple parameters in the water treatment process with little need for maintenance, calibration, or operator intervention. The company has experienced a compound annual growth rate of 40 percent over its 15-year history as a direct result of the technology's success.

2010-01-01

211

Real time reflectometer. [measurement of specular reflectance  

NASA Technical Reports Server (NTRS)

A real time reflectometer with the particular utility of measuring fairly rapid (transient) changes in the specular reflectance of a sample which is continuously exposed to a perturbing environment is described. A fixed radiation source, a fixed detector, a uniformly rotating sample wheel, and a uniformly rotating optical wheel protect against misalignment problems. The reflectometer operates by comparing the measurings of a reflected signal with that of a reference signal made within fractions of a second of one another. Reflectance is measured in the infrared, visible, and vacuum ultraviolet regions.

Zwiener, J. M. (inventor)

1977-01-01

212

Following Michael Faraday's Footprints  

ERIC Educational Resources Information Center

Last fall I had the good fortune of receiving financial support to shoot a documentary about Michael Faraday. I took the opportunity to learn more about this great experimentalist and to visit the highlights of places in his life. In this paper, I would like to share a list and description of some of the most remarkable places in London suitable…

Galeano, Javier

2011-01-01

213

Ultraviolet Faraday Rotator Glass.  

National Technical Information Service (NTIS)

A Faraday rotator glass composition based on a fluoride glass, phosphate glass, fluorophosphate glass or a mixture there of is dope with a lanthanide in concentration sufficient to provide a Verdet constant above at least 2870 deg/Tesla-meter (1 MIN/CM-Oe...

J. L. Dexter D. G. Cooper D. H. Blackburn

1993-01-01

214

Cell Phone Faraday Cage  

NSDL National Science Digital Library

In this activity, construct the strongest "dead zone" for a cell phone -- a Faraday Cage! Use this activity to explore conductivity, as well as how cell phones work and send electromagnetic waves. This activity guide includes a step-by-step instructional video.

Center, Saint L.

2013-01-17

215

Real-time virtual room acoustic simulation  

NASA Astrophysics Data System (ADS)

A realistic virtual room acoustic simulation has been implemented on a PC-based computer in near real-time. Room acoustics are calculated by the image source method using realistic absorption coefficients for a variety of realistic surfaces and programmed in MATLAB. The resulting impulse response filters are then applied in near real-time using fast convolution DSP techniques using data being read from a CD-ROM. The system was implemented in a virtual acoustic room facility. Optimizations have been performed to retain the realistic virtual room effect while minimizing computations through limited psycho-acoustic testing. In general, realistic anechoic to reverberant virtual rooms have been re-created with six 8192 coefficient filters. To provide realistic simulations, special care must be taken to accurately reproduce the low frequency acoustics. Since the virtual room acoustic facility was not totally anechoic (as are most anechoic chambers), inverse filters were applied to compensate for over-amplified acoustics at frequencies below 350 Hz.

Carneal, James P.; Johnson, Jan; Johnson, Troge; Johnson, Marty

2003-10-01

216

Real-time airborne data management system  

NASA Astrophysics Data System (ADS)

ITT has developed and demonstrated a real-time airborne data management system that ingests, compresses, stores, and streams imagery and video data from sensors based on users' needs. The data management system was designed to be sensor agnostic, which was demonstrated when ITT quickly integrated several different cameras including an HD video camera, an IR video camera, and large framing cameras. The data is compressed in real-time using ITT's high-speed JPEG 2000 compression core and stored in the airborne unit. The data is then interactively served to users over downlink communication based on the users' requests. This system's capability was demonstrated in several test flights where data was collected from the sensors at 132 megapixels per second (1.5 gigabits per second), compressed, stored, and interactively served as regions of interest to multiple users over a 48 megabit/second communication link. This data management system is currently being incorporated into airborne systems for military and civil applications.

Pellechia, Matthew; Brower, Bernard; Lourette, Richard; Shuler, Roddy; Boland, John; Rajan, S. Danny

2009-05-01

217

Development of real-time photoacoustic microscopy  

NASA Astrophysics Data System (ADS)

Photoacoustic tomography detecting ultrasound signals generated from photon absorption provides optical absorption contrast in vivo for structural, functional and molecular imaging. Although photoacoustic tomography technology has grown fast in recent years, real-time photoacoustic imaging with cellular spatial resolution are still strongly demanded. We developed a photoacoustic microscopy which has video-rate imaging capability with cellular spatial resolution. The system consists of a single-element focused ultrasound transducer, a fiber-based light-delivery subsystem, a voice-coil translation stage, a motion controller, and a data acquisition subsystem. A compact cube is employed to split optical and acoustic beams. The mass of the entire scanning photoacoustic probe is less than 40 grams, which minimizes potential vibrations and inertial effects, therefore, makes it capable to scan fast. The imaging system is capable of acquiring 20 cross-sectional (B-scan) images per second over 9 mm, and up to 40 B-scan images per second over 1 mm. Focused laser beams provide a lateral resolution of five microns. Confocal deployment of optical and acoustic focuses provides higher SNR than optical scanning approach. Micron-sized carbon particles flowing in silicone tubing and in vivo blood flows were imaged in video-rate, which demonstrated the capability to image highly dynamic biological processes in vivo with cellular resolution. This real-time high-resolution photoacoustic imaging system provides a promising approach for various in vivo imaging and quantitative studies.

Wang, Lidai; Maslov, Konstantin; Yao, Junjie; Li, Li; Wang, Lihong V.

2011-02-01

218

Real-time sensor data validation  

NASA Technical Reports Server (NTRS)

This report describes the status of an on-going effort to develop software capable of detecting sensor failures on rocket engines in real time. This software could be used in a rocket engine controller to prevent the erroneous shutdown of an engine due to sensor failures which would otherwise be interpreted as engine failures by the control software. The approach taken combines analytical redundancy with Bayesian belief networks to provide a solution which has well defined real-time characteristics and well-defined error rates. Analytical redundancy is a technique in which a sensor's value is predicted by using values from other sensors and known or empirically derived mathematical relations. A set of sensors and a set of relations among them form a network of cross-checks which can be used to periodically validate all of the sensors in the network. Bayesian belief networks provide a method of determining if each of the sensors in the network is valid, given the results of the cross-checks. This approach has been successfully demonstrated on the Technology Test Bed Engine at the NASA Marshall Space Flight Center. Current efforts are focused on extending the system to provide a validation capability for 100 sensors on the Space Shuttle Main Engine.

Bickmore, Timothy W.

1994-01-01

219

On quantum tunneling in real time  

NASA Astrophysics Data System (ADS)

A detailed real time description of quantum tunneling in the semiclassical limit is given, using complex classical trajectories. This picture connects naturally with the ideas of post-selection and weak measurement introduced by Aharonov and collaborators. I show that one can precisely identify the complex classical trajectory which a post-selected tunneling particle has followed, and which dominates the path integral in the limit as Planck's constant \\hbar tends to zero. Detailed analytical calculations are presented for tunneling in cubic and quartic potentials. For a long post-selected tunneling time, the imaginary part of the tunneling coordinate is found to achieve very large values just before the particle tunnels. I discuss how the real and imaginary parts of the particle's coordinate may, in principle, be independently measured using weak measurements. It would be very interesting to observe this effect, which would demonstrate the essential role of complex numbers in our closest possible classical description of reality. Extensions to quantum field theory and general relativity are briefly discussed.

Turok, Neil

2014-06-01

220

REal-time COsmic Ray Database (RECORD)  

NASA Astrophysics Data System (ADS)

In this paper we present a first distributed REal-time COsmic Ray Database (RECORD). The aim of the project is to develop a unified database with data from different neutron monitors collected together, in unified format and to provide a user with several commonly used data access methods. The database contains not only original cosmic ray data but also auxiliary data necessary for scientific data analysis. Currently the database includes Lomn.Stit, Moscow, Oulu; Tixie Bay, Yakutsk stations. The main database server is located in IKFIA SB RAS (Yakutsk) but there will be several mirrors of the database. The database and all its mirrors are up dated on the nearly real-time (1 hour) basis. The data access software includes WWW-interface, Perl scripts and C library, which may be linked to a user program. Most of frequently used functions are implemented to make it operable to users without SQL language knowledge. A draft of the data representation standard is suggested, based on common practice of neutron monitor community. The database engine is freely distributed open-sourced PostgreSQL server coupled with a set of replication to ols developed at Bio engineering division of the IRCCS E.Medea, Italy.

Usoskin, I.; Kozlov, Valery; Ksenofontov, Leonid, Kudela, Karel; Starodubtsev, Sergei; Turpanov, Alexey; Yanke, Victor

2003-07-01

221

Neutron monitor database in real time  

NASA Astrophysics Data System (ADS)

A first distributed Real Time Cosmic Ray Database using measurements of several neutron monitors is presented. The aim of the project is to develop a unified database with data from different neutron monitors collected together, in unified format and to provide a user with several commonly used data access methods. The database contains original cosmic ray as well as all housekeeping and technical data necessary for scientific data analysis. Currently the database includes Lomnicky Stit, Moscow, Oulu, Tixie Bay, Yakutsk stations and it is opened for other neutron monitors. The main database server is located in IKFIA SB RAS (Yakutsk) but there will be several mirrors of the database. The datbase and all its mirrors are updated on the nearly real-time (1 hour) basis. The data access software includes WWW-interface, Perl scipts and C library, which may be linked to a user program. Most of frequently used functions are implemented to make it operable to users without SQL language knowledge. A draft of the data representation standard is suggested, based on common practice of neutron monitor community. The database engine is freely distributed open-sourced PostgreSQL server coupled with a set of replication tools developed at Bioengineering division of the IRCCS E. Medea, Italy.

Kozlov, Valery; Kudela, Karel; Starodubtsev, Sergei; Turpanov, Alexey; Usoskin, Ilya; Yanke, Victor

2003-09-01

222

Testing Real-Time Systems Using TINA  

NASA Astrophysics Data System (ADS)

The paper presents a technique for model-based black-box conformance testing of real-time systems using the Time Petri Net Analyzer TINA. Such test suites are derived from a prioritized time Petri net composed of two concurrent sub-nets specifying respectively the expected behaviour of the system under test and its environment.We describe how the toolbox TINA has been extended to support automatic generation of time-optimal test suites. The result is optimal in the sense that the set of test cases in the test suite have the shortest possible accumulated time to be executed. Input/output conformance serves as the notion of implementation correctness, essentially timed trace inclusion taking environment assumptions into account. Test cases selection is based either on using manually formulated test purposes or automatically from various coverage criteria specifying structural criteria of the model to be fulfilled by the test suite. We discuss how test purposes and coverage criterion are specified in the linear temporal logic SE-LTL, derive test sequences, and assign verdicts.

Adjir, Noureddine; de Saqui-Sannes, Pierre; Rahmouni, Kamel Mustapha

223

Real Time Nonequilibrium Dynamics of Quantum Plasmas  

NASA Astrophysics Data System (ADS)

We implement the dynamical renormalization group (DRG) using the hard thermal loop (HTL) approximation for the real-time nonequilibrium dynamics in hot plasmas. The focus is on the study of the relaxation of gauge and fermionic mean fields and on the quantum kinetics of the photon and fermion distribution functions. As a concrete physical prediction, we find that for a QGP of temperature T~200 MeV and lifetime 10<=t<= 50 fm/c there is a new contribution to the hard (k~T) photon production form off-shell bremsstrahlung (q-->q? and $\\bar{q}\\to \\bar{q}\\gamma$) at just O(?) that grows logarithmically in time and is comparable to the known on-shell Compton scattering and pair annihilation at O(??s).

de Vega, H. J.

224

A tool for modeling concurrent real-time computation  

NASA Technical Reports Server (NTRS)

Real-time computation is a significant area of research in general, and in AI in particular. The complexity of practical real-time problems demands use of knowledge-based problem solving techniques while satisfying real-time performance constraints. Since the demands of a complex real-time problem cannot be predicted (owing to the dynamic nature of the environment) powerful dynamic resource control techniques are needed to monitor and control the performance. A real-time computation model for a real-time tool, an implementation of the QP-Net simulator on a Symbolics machine, and an implementation on a Butterfly multiprocessor machine are briefly described.

Sharma, D. D.; Huang, Shie-Rei; Bhatt, Rahul; Sridharan, N. S.

1990-01-01

225

Fast Faraday Cup With High Bandwidth  

DOEpatents

A circuit card stripline Fast Faraday cup quantitatively measures the picosecond time structure of a charged particle beam. The stripline configuration maintains signal integrity, and stitching of the stripline increases the bandwidth. A calibration procedure ensures the measurement of the absolute charge and time structure of the charged particle beam.

Deibele, Craig E [Knoxville, TN

2006-03-14

226

Passive Global, Real-Time TEC Monitoring  

NASA Astrophysics Data System (ADS)

Sensors are being developed to provide a satellite-based VHF global lightning monitor (e.g. Suszcynsky, et al., "VHF Global Lightning and Severe Storm Monitoring from Space: Storm-level Characterization of VHF Lightning Emissions," EOS Trans. AGU 2001 Fall Mt. Prog. And Abstr. 82, No. 47, F143, 2001). Dispersive effects of propagation of the lightning electromagnetic wave through the ionospheric and plasmaspheric plasmas cause the higher frequency components to arrive at the satellite before lower frequency components. From the time-of-arrival at several frequencies we can derive the TEC between the satellite and the lightning. Using multi-satellite techniques we can geolocate the lightning and the ionospheric penetration point quite accurately. A single ground station could provide essentially real-time regional TEC coverage. Four ground stations could provide global, real-time TEC measurements to supplement existing ground-based systems, especially over broad ocean areas. We expect several lightning detections per satellite per minute. Temporal resolution will be limited only by ground segment processing. Spatial coverage and resolution will be limited by lightning occurrence, but many commercial sector TEC requirements are also correlated to lightning occurrence. With our FORTE (Fast On-orbit Recording of Transient Events) satellite we sense lightning over most of the globe including the oceans. We expect to determine TEC spatial gradients with tens of km resolution. This capability should be especially useful in severe convective weather to aircraft using GPS-based navigation, e.g. the FAA's Wide Area Augmentation System (WAAS).

Pongratz, M. B.

2002-12-01

227

Real-Time Data Services for Cyber Physical Systems  

Microsoft Academic Search

Cyber Physical Systems (CPSs) have grand visions with great socio-economic impacts such as blackout-free electricity supply and real-time disaster recovery. A key challenge is providing real-time data services for CPSs. Existing real-time data management techniques and wireless sensor networks (WSNs) fall far short to support timely, secure real-time data services for CPSs. In this paper, we present a novel information-centric

Kyoung-don Kang; Sang Hyuk Son

2008-01-01

228

An uRT51 real-time processor evaluation  

Microsoft Academic Search

Real-time systems are used in control applications. However, real-time systems may introduce undesirable effects on the control application. Stability, overshoot and settling time are affected when an inadequate real-time system is used. The uRT51 is an embedded processor designed for real-time applications. In this paper we analyse the perturbations that the uRT51 produces on a control application using two of

Ricardo Cayssials; Edgardo Ferro

2009-01-01

229

REAL TIME SCHEDULING METHODS REQUIREMENTS IN DISTRIBUTED CONTROL SYSTEMS  

Microsoft Academic Search

Distributed control systems involve three main disciplines: control systems, real time systems, and communication systems. Control systems, due their stringent timing constraints, demand real time computing technology. Distributed control systems need communication systems when distributing sensors, actuators, the control procedures and data messaging. In general, demands of distributed control systems and properties of real time scheduling algorithms differ, for example,

Pau Martí; Ricard Villà; Josep M. Fuertes; Gerhard Fohler

2000-01-01

230

Extreme events in Faraday waves  

NASA Astrophysics Data System (ADS)

Observations of extreme wave events in the ocean are rare due to their low statistical probability. In the laboratory however, the evolution of extreme wave events can be studied in great detail with high spatial and temporal resolution. The reported surface wave experiments in the short wavelength gravity-capillary range aim to contribute to the understanding of some of the underlying mechanisms for rogue wave generation. In this talk, we report on extreme wave events in parametrically excited Faraday waves. Faraday waves appear if a fluid is accelerated (normal to the fluid surface) above a critical threshold. A variety of novel tools have been deployed to characterize the 2D surface elevation. The results presented show spatio-temporal and statistical data on the surface wave conditions leading up to extreme wave events. The peak in wave amplitude during such an event is shown to exceed six times the standard deviation of the average wave field with significantly increased statistical probability compared to the background wave field [1]. The experiments also show that parametrically excited waves can be viewed as assembles of oscillons [2] (or oscillating solitons) where modulation instability seems to play a crucial role in their formation. More detailed studies on the oscillon dynamics reveal that the onset of an increased probability of extreme wave events correlates with the increase in the oscillons mobility and merger [3]. Reference: 1. Xia H., Maimbourg T., Punzmann H., and Shats M., Oscillon dynamics and rogue wave generation in Faraday surface ripples, Physical Review Letters 109, 114502 (2012) 2. Shats M., Xia H., and Punzmann H., Parametrically excited water surface ripples as ensembles of oscillons, Physical Review Letters 108, 034502 (2012) 3. Shats M., Punzmann H., Xia H., Capillary rogue waves, Physical Review Letters, 104, 104503 (2010)

Punzmann, Horst; Shats, Michael; Xia, Hua

2014-05-01

231

A real-time prediction of UTC  

NASA Technical Reports Server (NTRS)

The reference time scale for all scientific and technologic applications on the Earth, the Universal Coordinated Time (UTC), must be as stable, reliable, and accurate as possible. With this in view the BIPM and before it the BIH, have always calculated and then disseminated UTC with a delay of about 80 days. There are three fundamental reasons for doing this: (1) It takes some weeks for data, gathered from some 200 clocks spread world-wide, to be collected and for errors to be eliminated; (2) changes in clock rates can only be measured with high precision well after the fact; and (3) the measurement noise originating in time links, in particular using Loran-C, is smoothed out only when averaging over an extended period. Until mid-1992, the ultimate stability of UTC was reached at averaging times of about 100 days and corresponded to an Allan deviation sigma(sub y)(tau) of about 1,5x10(exp -14) then compared to the best primary clock in the world, the PTB CS2. For several years now, a predicted UTC has been computed by the USNO through an extrapolation of the values as published in deferred time by the BIPM. This is made available through the USNO Series 4, through the USNO Automated Data Service, and through GPS signals. Due to the instability of UTC, the poor predictability of the available clocks, and the intentional SA degradation of GPS signals, the real-time access to this extrapolated UTC has represented the true deferred-time UTC only to within several hundreds of nanoseconds.

Thomas, Claudine; Allan, David W.

1994-01-01

232

Real time speech formant analyzer and display  

DOEpatents

A speech analyzer for interpretation of sound includes a sound input which converts the sound into a signal representing the sound. The signal is passed through a plurality of frequency pass filters to derive a plurality of frequency formants. These formants are converted to voltage signals by frequency-to-voltage converters and then are prepared for visual display in continuous real time. Parameters from the inputted sound are also derived and displayed. The display may then be interpreted by the user. The preferred embodiment includes a microprocessor which is interfaced with a television set for displaying of the sound formants. The microprocessor software enables the sound analyzer to present a variety of display modes for interpretive and therapeutic used by the user. 19 figs.

Holland, G.E.; Struve, W.S.; Homer, J.F.

1987-02-03

233

A Measure of Real-Time Intelligence  

NASA Astrophysics Data System (ADS)

We propose a new measure of intelligence for general reinforcement learning agents, based on the notion that an agent's environment can change at any step of execution of the agent. That is, an agent is considered to be interacting with its environment in real-time. In this sense, the resulting intelligence measure is more general than the universal intelligence measure (Legg and Hutter, 2007) and the anytime universal intelligence test (Hernández-Orallo and Dowe, 2010). A major advantage of the measure is that an agent's computational complexity is factored into the measure in a natural manner. We show that there exist agents with intelligence arbitrarily close to the theoretical maximum, and that the intelligence of agents depends on their parallel processing capability. We thus believe that the measure can provide a better evaluation of agents and guidance for building practical agents with high intelligence.

Gavane, Vaibhav

2013-03-01

234

Near real-time stereo vision system  

NASA Astrophysics Data System (ADS)

The apparatus for a near real-time stereo vision system for use with a robotic vehicle is described. The system is comprised of two cameras mounted on three-axis rotation platforms, image-processing boards, a CPU, and specialized stereo vision algorithms. Bandpass-filtered image pyramids are computed, stereo matching is performed by least-squares correlation, and confidence ranges are estimated by means of Bayes' theorem. In particular, Laplacian image pyramids are built and disparity maps are produced from the 60 x 64 level of the pyramids at rates of up to 2 seconds per image pair. The first autonomous cross-country robotic traverses (of up to 100 meters) have been achieved using the stereo vision system of the present invention with all computing done onboard the vehicle. The overall approach disclosed herein provides a unifying paradigm for practical domain-independent stereo ranging.

Matthies, Larry H.; Anderson, Charles H.

1991-12-01

235

Real time 3D holographic display  

NASA Astrophysics Data System (ADS)

In this article is described a Real Time 3D video display of holographic images based on the principle of sequential scanning of holograms with HPO (horizontal parallax only) generated by a high speed computer and sent at high frame rate to DMD, and visualized by an anamorphic optical group. The device displays binary amplitude and phase modulated images opportunely synchronized and scanned by a galvanometric mirror or polygonal mirror driven by the control electronic circuitry. The elementary holograms are generated by a resident hardware which, through interpolation, generates single elementary holograms starting from images and depth map. The device operates with incoherent light (integral images) or with coherent light (holographic display) by changing the optical visualization group.

Loreti, Luigi; Ceccarelli, R.; Loreti, A.; Borro, A.

2012-02-01

236

In-line real time air monitor  

DOEpatents

An in-line gas monitor capable of accurate gas composition analysis in a continuous real time manner even under strong applied vacuum conditions operates by mixing an air sample with helium forming a sample gas in two complementary sample loops embedded in a manifold which includes two pairs of 3-way solenoid valves. The sample gas is then analyzed in an ion trap mass spectrometer on a continuous basis. Two valve drivers actuate the two pairs of 3-way valves in a reciprocating fashion, so that there is always flow through the in-line gas monitor via one or the other of the sample loops. The duty cycle for the two pairs of 3-way valves is varied by tuning the two valve drivers to a duty cycle typically between 0.2 to 0.7 seconds. 3 figs.

Wise, M.B.; Thompson, C.V.

1998-07-14

237

Taking advantage of real-time pricing  

SciTech Connect

Linking RTP with automatic energy management and control systems can create win-win scenarios for utilities and their commercial/industrial customers. Widely offered by utilities in the United States and abroad, real-time pricing (RTP) is a proven method of reducing energy costs for a broad range of commercial and industrial customers. Utilities in turn benefit directly by retaining key customers. Now EPRI is leading efforts to make RTP even more attractive to power suppliers and consumers alike. Linking automated energy management systems in customers` commercial buildings and industrial facilities to hourly price signals from the utility can be beneficial to both parties, as shown in several recent EPRI-sponsored demonstrations. With industry deregulation, as new entities like energy service companies change the way electricity is offered to customers, RTP is likely to become part of the vocabulary of more power providers, service providers, regulators, and end users.

Hoffman, S.; Renner, R.; Drenker, S.; Carmicheal, L.; Flood, J.

1997-09-01

238

Real time speech formant analyzer and display  

DOEpatents

A speech analyzer for interpretation of sound includes a sound input which converts the sound into a signal representing the sound. The signal is passed through a plurality of frequency pass filters to derive a plurality of frequency formants. These formants are converted to voltage signals by frequency-to-voltage converters and then are prepared for visual display in continuous real time. Parameters from the inputted sound are also derived and displayed. The display may then be interpreted by the user. The preferred embodiment includes a microprocessor which is interfaced with a television set for displaying of the sound formants. The microprocessor software enables the sound analyzer to present a variety of display modes for interpretive and therapeutic used by the user.

Holland, George E. (Ames, IA); Struve, Walter S. (Ames, IA); Homer, John F. (Ames, IA)

1987-01-01

239

Near real-time stereo vision system  

NASA Technical Reports Server (NTRS)

The apparatus for a near real-time stereo vision system for use with a robotic vehicle is described. The system is comprised of two cameras mounted on three-axis rotation platforms, image-processing boards, a CPU, and specialized stereo vision algorithms. Bandpass-filtered image pyramids are computed, stereo matching is performed by least-squares correlation, and confidence ranges are estimated by means of Bayes' theorem. In particular, Laplacian image pyramids are built and disparity maps are produced from the 60 x 64 level of the pyramids at rates of up to 2 seconds per image pair. The first autonomous cross-country robotic traverses (of up to 100 meters) have been achieved using the stereo vision system of the present invention with all computing done onboard the vehicle. The overall approach disclosed herein provides a unifying paradigm for practical domain-independent stereo ranging.

Anderson, Charles H. (inventor); Matthies, Larry H. (inventor)

1993-01-01

240

Optimal, real-time control--colliders  

SciTech Connect

With reasonable definitions, optimal control is possible for both classical and quantal systems with new approaches called PISC(Parallel) and NISC(Neural) from analogy with RISC (Reduced Instruction Set Computing). If control equals interaction, observation and comparison to some figure of merit with interaction via external fields, then optimization comes from varying these fields to give design or operating goals. Structural stability can then give us tolerance and design constraints. But simulations use simplified models, are not in real-time and assume fixed or stationary conditions, so optimal control goes far beyond convergence rates of algorithms. It is inseparable from design and this has many implications for colliders. 12 refs., 3 figs.

Spencer, J.E.

1991-05-01

241

REAL TIME DATA FOR REMEDIATION ACTIVITIES [11505  

SciTech Connect

Health physicists from the CH2M HILL Plateau Remediation Company collaborated with Berkeley Nucleonics Corporation to modify the SAM 940 isotope identifier instrument to be used for nuclear waste remediation. These modifications coupled with existing capabilities of the SAM 940 have proven to be invaluable during remediation activities, reducing disposal costs by allowing swift remediation of targeted areas that have been identified as having isotopes of concern (IOC), and eliminating multiple visits to sites by declaring an excavation site clear of IOCs before demobilizing from the site. These advantages are enabled by accumulating spectral data for specific isotopes that is nearly 100 percent free of false positives, which are filtered out in 'real time.'

BROCK CT

2011-01-13

242

Satellite clock corrections estimation to accomplish real time ppp: experiments for brazilian real time network  

NASA Astrophysics Data System (ADS)

The real time PPP method requires the availability of real time precise orbits and satellites clocks corrections. Currently, it is possible to apply the solutions of clocks and orbits available by BKG within the context of IGS Pilot project or by using the operational predicted IGU ephemeris. The accuracy of the satellite position available in the IGU is enough for several applications requiring good quality. However, the satellites clocks corrections do not provide enough accuracy (3 ns ~ 0.9 m) to accomplish real time PPP with the same level of accuracy. Therefore, for real time PPP application it is necessary to further research and develop appropriated methodologies for estimating the satellite clock corrections in real time with better accuracy. Currently, it is possible to apply the real time solutions of clocks and orbits available by Federal Agency for Cartography and Geodesy (BKG) within the context of IGS Pilot project. The BKG corrections are disseminated by a new proposed format of the RTCM 3.x and can be applied in the broadcasted orbits and clocks. Some investigations have been proposed for the estimation of the satellite clock corrections using GNSS code and phase observable at the double difference level between satellites and epochs (MERVAT, DOUSA, 2007). Another possibility consists of applying a Kalman Filter in the PPP network mode (HAUSCHILD, 2010) and it is also possible the integration of both methods, using network PPP and observables at double difference level in specific time intervals (ZHANG; LI; GUO, 2010). For this work the methodology adopted consists in the estimation of the satellite clock corrections based on the data adjustment in the PPP mode, but for a network of GNSS stations. The clock solution can be solved by using two types of observables: code smoothed by carrier phase or undifferenced code together with carrier phase. In the former, we estimate receiver clock error; satellite clock correction and troposphere, considering that the phase ambiguities are eliminated when applying differences between consecutive epochs. However, when using undifferenced code and phase, the ambiguities may be estimated together with receiver clock errors, satellite clock corrections and troposphere parameters. In both strategies it is also possible to correct the troposphere delay from a Numerical Weather Forecast Model instead of estimating it. The prediction of the satellite clock correction can be performed using a straight line or a second degree polynomial using the time series of the estimated satellites clocks. To estimate satellite clock correction and to accomplish real time PPP two pieces of software have been developed, respectively, "RT_PPP" and "RT_SAT_CLOCK". The system (RT_PPP) is able to process GNSS code and phase data using precise ephemeris and precise satellites clocks corrections together with several corrections required for PPP. In the software RT_SAT_CLOCK we apply a Kalman filter algorithm to estimate satellite clock correction in the network PPP mode. In this case, all PPP corrections must be applied for each station. The experiments were generated in real time and post-processed mode (simulating real time) considering data from the Brazilian continuous GPS network and also from the IGS network in a global satellite clock solution. We have used IGU ephemeris for satellite position and estimated the satellite clock corrections, performing the updates as soon as new ephemeris files were available. Experiments were accomplished in order to assess the accuracy of the estimated clocks when using the Brazilian Numerical Weather Forecast Model (BNWFM) from CPTEC/INPE and also using the ZTD from European Centre for Medium-Range Weather Forecasts (ECMWF) together with Vienna Mapping Function VMF or estimating troposphere with clocks and ambiguities in the Kalman Filter. The daily precision of the estimated satellite clock corrections reached the order of 0.15 nanoseconds. The clocks were applied in the Real Time PPP for Brazilian network stations and also for fligh

Marques, Haroldo; Monico, João; Aquino, Marcio; Melo, Weyller

2014-05-01

243

Ames Lab 101: Real-Time 3D Imaging  

ScienceCinema

Ames Laboratory scientist Song Zhang explains his real-time 3-D imaging technology. The technique can be used to create high-resolution, real-time, precise, 3-D images for use in healthcare, security, and entertainment applications.

244

Swell Software Crafts Artificial Clouds in Real-Time  

NSF Publications Database

... of this News Tip: SWELL SOFTWARE CRAFTS ARTIFICIAL CLOUDS IN REAL-TIME NEW REPORT IDENTIFIES GRAND ... SMART-PAPER? DISPLAYS Swell Software Crafts Artificial Clouds in Real-Time For artists creating ...

245

Real-Time Nonintrusive Detection of Driver Drowsiness: Phase II.  

National Technical Information Service (NTIS)

This project is the extension of the Northland Advanced Transportation System Research Laboratory (NATSRL) FY 2008 project titled Real-time Nonintrusive Detection of Driver Drowsiness, which aims to develop a real-time, nonintrusive driver drowsiness dete...

X. Yu

2010-01-01

246

Ames Lab 101: Real-Time 3D Imaging  

SciTech Connect

Ames Laboratory scientist Song Zhang explains his real-time 3-D imaging technology. The technique can be used to create high-resolution, real-time, precise, 3-D images for use in healthcare, security, and entertainment applications.

Zhang, Song

2010-01-01

247

Ames Lab 101: Real-Time 3D Imaging  

ScienceCinema

Ames Laboratory scientist Song Zhang explains his real-time 3-D imaging technology. The technique can be used to create high-resolution, real-time, precise, 3-D images for use in healthcare, security, and entertainment applications.

Zhang, Song

2012-08-29

248

Expert Systems for Real-Time Monitoring and Fault Diagnosis.  

National Technical Information Service (NTIS)

Methods for building real-time onboard expert systems were investigated, and the use of expert systems technology was demonstrated in improving the performance of current real-time onboard monitoring and fault diagnosis applications. The potential applica...

S. J. Edwards A. K. Caglayan

1989-01-01

249

Frame work for real time Optimal Power Flow using real time measurement tools and techniques  

Microsoft Academic Search

The present power grid is complex due to enormous real time applications and hence requires new developmental areas of smart grid. As such, the grid which has been slowly becoming ‘modernized’ to meet the new challenges is overly stressed. In a bid to develop enabling technologies so as to address the mitigation of the various stresses the power grid faces,

James A. Momoh; Yesha Baxi; Ayobami O. Idubor

2011-01-01

250

Real-time testing of hvdc circuit breakers part II: real-time cases  

Microsoft Academic Search

A new real-time testing technique for hvdc breakers using the Electromagnetic Transient Program (EMTP) has been proposed. In this paper, different topologies of hvdc systems with full-size controlled converters are accurately modeled and the hvdc circuit breakers are appropriately located. Then, miscella- neous switching duties are examined. Metallic Return Protecting Breaker (MRPB) and fault clearing processes are fully analyzed for

H. A. Darwish; M. A. Izzularab; N. I. Elkalashy

2004-01-01

251

Real-Time Optical Antimicrobial Susceptibility Testing  

PubMed Central

Rapid antibiotic susceptibility testing is in high demand in health care fields as antimicrobial-resistant bacterial strains emerge and spread. Here, we describe an optical screening system (oCelloScope) which, based on time-lapse imaging of 96 bacteria-antibiotic combinations at a time, introduces real-time detection of bacterial growth and antimicrobial susceptibility with imaging material to support the automatically generated graphs. Automated antibiotic susceptibility tests of a monoculture showed statistically significant antibiotic effects within 6 min and within 30 min in complex samples from pigs suffering from catheter-associated urinary tract infections. The oCelloScope system provides a fast high-throughput screening method for detecting bacterial susceptibility that might entail an earlier diagnosis and introduction of appropriate targeted therapy and thus combat the threat from multidrug-resistant pathogenic bacteria. The oCelloScope system can be employed for a broad range of applications within bacteriology and might present new vistas as a point-of-care instrument in clinical and veterinary settings.

Andersen, Klaus R.; J?rgensen, Erik; Droce, Aida; Olesen, Tom; Jensen, Bent B.; Rosenvinge, Flemming S.; Sondergaard, Teis E.

2013-01-01

252

Real-time scheduling of software tasks  

SciTech Connect

When designing real-time systems, it is often desirable to schedule execution of software tasks based on the occurrence of events. The events may be clock ticks, interrupts from a hardware device, or software signals from other software tasks. If the nature of the events, is well understood, this scheduling is normally a static part of the system design. If the nature of the events is not completely understood, or is expected to change over time, it may be necessary to provide a mechanism for adjusting the scheduling of the software tasks. RHIC front-end computers (FECs) provide such a mechanism. The goals in designing this mechanism were to be as independent as possible of the underlying operating system, to allow for future expansion of the mechanism to handle new types of events, and to allow easy configuration. Some considerations which steered the design were programming paradigm (object oriented vs. procedural), programming language, and whether events are merely interesting moments in time, or whether they intrinsically have data associated with them. The design also needed to address performance and robustness tradeoffs involving shared task contexts, task priorities, and use of interrupt service routine (ISR) contexts vs. task contexts. This paper will explore these considerations and tradeoffs.

Hoff, L.T.

1995-12-01

253

High-level real-time programming in Java  

Microsoft Academic Search

Real-time systems have reached a level of complexity beyond the scaling capability of the low-level or restricted languages traditionally used for real-time programming.While Metronome garbage collection has made it practical to use Java to implement real-time systems, many challenges remain for the construction of complex real-time systems, some specific to the use of Java and others simply due to the

David F. Bacon; Perry Cheng; David Grove; Michael Hind; V. T. Rajan; Eran Yahav; Matthias Hauswirth; Christoph M. Kirsch; Daniel Spoonhower; Martin T. Vechev

2005-01-01

254

Integrated scenario in JET using real-time profile control  

Microsoft Academic Search

The recent development of real-time measurements and control tools in JET has enhanced the reliability and reproducibility of the relevant ITER scenarios. Diagnostics such as charge exchange, interfero-polarimetry, electron cyclotron emission have been upgraded for real-time measurements. In addition, real-time processes like magnetic equilibrium and q profile reconstruction have been developed and applied successfully in real-time q profile control experiments

E. Joffrin; F. Crisanti; R. Felton; X. Litaudon; D. Mazon; D. Moreau; L. Zabeo; R. Albanese; M. Ariola; D. Alves; O. Barana; V. Basiuk; A. Bécoulet; M. Bécoulet; J. Blum; T. Bolzonnella; K. Bosak; J. M. Chareau; M. de Baar; E. de la Luna; P. de Vries; P. Dumortier; D. Elbeze; J. Farthing; H. Fernandes; C. Fenzi; R. Giannella; K. Guenther; J. Harling; N. Hawkes; T. C. Hender; D. F. Howell; P. Heesterman; F. Imbeaux; P. Innocente; L. Laborde; G. Lloyd; P. J. Lomas; D. C. McDonald; J. Mailloux; M. Mantsinen; A. Messiaen; A. Murari; J. Ongena; F. Orsitto; V. Pericoli-Ridolfini; M. Riva; J. Sanchez; F. Sartori; O. Sauter; A. C. C. Sips; T. Tala; A. Tuccillo; D. Van Ester; K.-D. Zastrow; M. Zerbini; JET EFDA Programme

2003-01-01

255

Testing real-time systems using genetic algorithms  

Microsoft Academic Search

The development of real-time systems is an essential industrial activity whose importance is increasing. The most important analytical method to assure the quality of real-time systems is dynamic testing. Testing is the only method which examines the actual run-time behaviour of real-time software, based on an execution in the real application environment. Dynamic aspects like the duration of computations, the

Joachim Wegener; Harmen Sthamer; Bryan F. Jones; David E. Eyres

1997-01-01

256

Modified Faraday cup  

DOEpatents

A tomographic technique for measuring the current density distribution in electron beams using electron beam profile data acquired from a modified Faraday cup to create an image of the current density in high and low power beams is disclosed. The modified Faraday cup includes a narrow slit and is rotated by a stepper motor and can be moved in the x, y and z directions. The beam is swept across the slit perpendicular thereto and controlled by deflection coils, and the slit rotated such that waveforms are taken every few degrees from 0{degree} to 360{degree} and the waveforms are recorded by a digitizing storage oscilloscope. Two-dimensional and three-dimensional images of the current density distribution in the beam can be reconstructed by computer tomography from this information, providing quantitative information about the beam focus and alignment. 12 figs.

Elmer, J.W.; Teruya, A.T.; O`Brien, D.W.

1996-09-10

257

Modified Faraday cup  

DOEpatents

A tomographic technique for measuring the current density distribution in electron beams using electron beam profile data acquired from a modified Faraday cup to create an image of the current density in high and low power beams. The modified Faraday cup includes a narrow slit and is rotated by a stepper motor and can be moved in the x, y and z directions. The beam is swept across the slit perpendicular thereto and controlled by deflection coils, and the slit rotated such that waveforms are taken every few degrees form 0.degree. to 360.degree. and the waveforms are recorded by a digitizing storage oscilloscope. Two-din-tensional and three-dimensional images of the current density distribution in the beam can be reconstructed by computer tomography from this information, providing quantitative information about the beam focus and alignment.

Elmer, John W. (Pleasanton, CA); Teruya, Alan T. (Livermore, CA); O'Brien, Dennis W. (Livermore, CA)

1996-01-01

258

The multispectral advanced volumetric real-time imaging compositor for real-time distributed scene generation  

NASA Astrophysics Data System (ADS)

AMRDEC has developed the Multi-spectral Advanced Volumetric Real-time Imaging Compositor (MAVRIC) prototype for distributed real-time hardware-in-the-loop (HWIL) scene generation. MAVRIC is a dynamic object-based energy conserved scene compositor that can seamlessly convolve distributed scene elements into temporally aligned physicsbased scenes for enhancing existing AMRDEC scene generation codes. The volumetric compositing process accepts input independent of depth order. This real-time compositor framework is built around AMRDEC's ContinuumCore API which provides the common messaging interface leveraging the Neutral Messaging Language (NML) for local, shared memory, reflective memory, network, and remote direct memory access (RDMA) communications and the Joint Signature Image Generator (JSIG) that provides energy conserved scene component interface at each render node. This structure allows for a highly scalable real-time environment capable of rendering individual objects at high fidelity while being considerate of real-time hardware-in-the-loop concerns, such as latency. As such, this system can be scaled to handle highly complex detailed scenes such as urban environments. This architecture provides the basis for common scene generation as it provides disparate scene elements to be calculated by various phenomenology codes and integrated seamlessly into a unified composited environment. This advanced capability is the gateway to higher fidelity scene generation such as ray-tracing. The high speed interconnects using PCI Express and InfiniBand were examined to support distributed scene generation whereby the scene graph, associated phenomenology, and the scene elements can be dynamically distributed across multiple high performance computing assets to maximize system performance.

Morris, Joseph W.; Ballard, Gary H.; Bunfield, Dennis H.; Peddycoart, Thomas E.; Trimble, Darian E.

2011-05-01

259

Real-time support for high performance aircraft operation  

NASA Technical Reports Server (NTRS)

The feasibility of real-time processing schemes using artificial neural networks (ANNs) is investigated. A rationale for digital neural nets is presented and a general processor architecture for control applications is illustrated. Research results on ANN structures for real-time applications are given. Research results on ANN algorithms for real-time control are also shown.

Vidal, Jacques J.

1989-01-01

260

Malicious data attack on real-time electricity market  

Microsoft Academic Search

Malicious data attacks to the real-time electricity market are studied. In particular, an adversary launches an attack by manipulating data from a set of meters with the goal of influencing revenues of a real-time market. The adversary must deal with the tradeoff between avoiding being detected by the control center and making maximum profit from the real time market. Optimal

Liyan Jia; Robert J. Thomas; Lang Tong

2011-01-01

261

The Advanced Correlation Tracker in Real-Time  

Microsoft Academic Search

Real-time detection, tracking and classification of objects in images are some of the more computationally demanding tasks in computer vision. Tracking systems such as correlation trackers are notorious for computational demands. Real-time performance is not achievable on general purpose microprocessors. This paper details the architectural issues tackled to create a real time realisation of the Advanced Correlation Tracker (ACT) algorithm

Sebastien Wong; Brendan Hennessy

2008-01-01

262

Tool for Modeling Concurrent Real-Time Computation.  

National Technical Information Service (NTIS)

Real-time computation is a significant area of research in general, and in AI in particular. The complexity of practical real-time problems demands use of knowledge-based problem solving techniques while satisfying real-time performance constraints. Since...

D. D. Sharma S. Huang R. Bhatt N. S. Sridharan

1990-01-01

263

76 FR 42536 - Real-Time System Management Information Program  

Federal Register 2010, 2011, 2012, 2013

...23 CFR Part 511 RIN 2125-AF19 Real-Time System Management Information Program AGENCY...travel conditions information via real-time information programs as required by Section...to the costs and benefits of the Real-Time System Management Information Program...

2011-07-19

264

75 FR 68418 - Real-Time System Management Information Program  

Federal Register 2010, 2011, 2012, 2013

...23 CFR Part 511 RIN 2125-AF19 Real-Time System Management Information Program AGENCY...Transportation (Secretary) to establish a Real-Time System Management Information Program that...the capability to monitor, in real-time, the traffic and travel conditions...

2010-11-08

265

Faraday Disk Dynamo Model  

NSDL National Science Digital Library

The EJS Faraday Disk Dynamo shows a conducting disk that rotates in a magnetic field. This produces a current (homopolar generator) and for certain configurations, it is a self-exciting dynamo. A self-exciting dynamo is the mechanical analog of a proposed mechanism to produce the earth and sun's magnetic fields. You can modify this simulation if you have Ejs installed by right-clicking within the plot and selecting âOpen Ejs Modelâ from the pop-up menu item. The Faraday Disk Dynamo model was created using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_em_FaradayDiskDynamo.jar file will run the program if Java is installed. Ejs is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models. Additional Ejs models are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or Ejs.

Cox, Anne

2009-09-28

266

Clinical experience with real-time ultrasound  

NASA Astrophysics Data System (ADS)

After testing the extended multimedia interface (EMMI) product which is an asynchronous transmission mode (ATM) user to network interface (UNI) of AT&T at the Society for Computer Applications in Radiology conference in Winston-Salem, the Department of Radiology together with AT&T are implementing a tele-ultrasound system to combine real- time ultrasound with the static imaging features of more traditional digital ultrasound systems. Our current ultrasound system archives digital images to an optical disk system. Static images are sent using our digital radiology systems. This could be transferring images from one digital imaging and communications (DICOM)-compliant machine to another, or the current image transfer methodologies. The prototype of a live ultrasound system using the EMMI demonstrated the feasibility of doing live ultrasound. We now are developing the scenarios using a mix of the two methodologies. Utilizing EMMI technology, radiologists at the BGSM review at a workstation both static images and real-time scanning done by a technologist on patients at a remote site in order to render on-line primary diagnosis. Our goal is to test the feasibility of operating an ultrasound laboratory at a remote site utilizing a trained technologist without the necessity of having a full-time radiologist at that site. Initial plans are for a radiologist to review an initial set of static images on a patient taken by the technologist. If further scanning is required, the EMMI is used to transmit real-time imaging and audio using the audio input of a standard microphone system and the National Television Standards Committee (NTSC) output of the ultrasound equipment from the remote site to the radiologist in the department review station. The EMMI digitally encodes this data and places it in an ATM format. This ATM data stream goes to the GCNS2000 and then to the other EMMI where the ATM data stream is decoded into the live studies and voice communication which are then received on a television and audio monitor. We also test live transmission of pediatric echocardiograms using the EMMI from a remote hospital to the Bowman Gray School of Medicine (BGSM) via a GCNS2000 ATM switch. This replaces the current method of having these studies transferred to a VHS tape and then mailed overnight to our pediatric cardiologist for review. This test should provide valuable insight into the staffing and operational requirements of a tele-ultrasound unit with pediatric echocardiogram capabilities. The EMMI thus provides a means for the radiologist to be in constant communication with the technologist to guide the scanning of areas in question and enable general problem solving. Live scans are sent from one EMMI at the remote site to the other EMMI at the review station in the radiology department via the GCNS2000 switch. This arrangement allows us to test the use of public ATM services for this application as this switch is a wide area, central office ATM switch. Static images are sent using the DICOM standard when available, otherwise the established institutional digital radiology methods are used.

Chimiak, William J.; Wolfman, Neil T.; Covitz, Wesley

1995-05-01

267

Real-time optoacoustic monitoring of stroke  

NASA Astrophysics Data System (ADS)

Characterizing disease progression and identifying possible therapeutic interventions in stroke is greatly aided by the use of longitudinal function imaging studies. In this study, we investigate the applicability of real-time multispectral optoacoustic tomography (MSOT) as a tool for non-invasive monitoring of the progression of stroke in the whole brain. The middle cerebral artery occlusion (MCAO) method was used to induce stroke. Mice were imaged under isoflurane anesthesia preoperatively and at several time points during and after the 60-minute occlusion. The animals were sacrificed after 24 hours and their excised brains frozen at -80°C for sectioning. The cryosection were stained using H&E staining to identify the ischemic lesion. Major vessels are readily identifiable in the whole mouse head in the in vivo optoacoustic scans. During ischemia, a reduction in cerebral blood volume is detectable in the cortex. Post ischemia, spectral unmixing of the optoacoustic signals shows an asymmetry of the deoxygenated hemoglobin in the hemisphere affected by MCAO. This hypoxic area was mainly located around the boundary of the ischemic lesion and was therefore identified as the ischemic penumbra. Non-invasive functional MSOT imaging is able to visualize the hypoxic penumbra in brains affected by stroke. Stopping the spread of the infarct area and revitalizing the penumbra is central in stroke research, this new imaging technique may therefore prove to be a valuable tool in the monitoring and developing new treatments.

Kneipp, Moritz; Turner, Jake; Hambauer, Sebastian; Krieg, Sandro M.; Lehmberg, Jens; Lindauer, Ute; Razansky, Daniel

2014-03-01

268

Real-Time Principal-Component Analysis  

NASA Technical Reports Server (NTRS)

A recently written computer program implements dominant-element-based gradient descent and dynamic initial learning rate (DOGEDYN), which was described in Method of Real-Time Principal-Component Analysis (NPO-40034) NASA Tech Briefs, Vol. 29, No. 1 (January 2005), page 59. To recapitulate: DOGEDYN is a method of sequential principal-component analysis (PCA) suitable for such applications as data compression and extraction of features from sets of data. In DOGEDYN, input data are represented as a sequence of vectors acquired at sampling times. The learning algorithm in DOGEDYN involves sequential extraction of principal vectors by means of a gradient descent in which only the dominant element is used at each iteration. Each iteration includes updating of elements of a weight matrix by amounts proportional to a dynamic initial learning rate chosen to increase the rate of convergence by compensating for the energy lost through the previous extraction of principal components. In comparison with a prior method of gradient-descent-based sequential PCA, DOGEDYN involves less computation and offers a greater rate of learning convergence. The sequential DOGEDYN computations require less memory than would parallel computations for the same purpose. The DOGEDYN software can be executed on a personal computer.

Duong, Vu; Duong, Tuan

2005-01-01

269

CRANS - CONFIGURABLE REAL-TIME ANALYSIS SYSTEM  

NASA Technical Reports Server (NTRS)

In a real-time environment, the results of changes or failures in a complex, interconnected system need evaluation quickly. Tabulations showing the effects of changes and/or failures of a given item in the system are generally only useful for a single input, and only with regard to that item. Subsequent changes become harder to evaluate as combinations of failures produce a cascade effect. When confronted by multiple indicated failures in the system, it becomes necessary to determine a single cause. In this case, failure tables are not very helpful. CRANS, the Configurable Real-time ANalysis System, can interpret a logic tree, constructed by the user, describing a complex system and determine the effects of changes and failures in it. Items in the tree are related to each other by Boolean operators. The user is then able to change the state of these items (ON/OFF FAILED/UNFAILED). The program then evaluates the logic tree based on these changes and determines any resultant changes to other items in the tree. CRANS can also search for a common cause for multiple item failures, and allow the user to explore the logic tree from within the program. A "help" mode and a reference check provide the user with a means of exploring an item's underlying logic from within the program. A commonality check determines single point failures for an item or group of items. Output is in the form of a user-defined matrix or matrices of colored boxes, each box representing an item or set of items from the logic tree. Input is via mouse selection of the matrix boxes, using the mouse buttons to toggle the state of the item. CRANS is written in C-language and requires the MIT X Window System, Version 11 Revision 4 or Revision 5. It requires 78K of RAM for execution and a three button mouse. It has been successfully implemented on Sun4 workstations running SunOS, HP9000 workstations running HP-UX, and DECstations running ULTRIX. No executable is provided on the distribution medium; however, a sample makefile is included. Sample input files are also included. The standard distribution medium is a .25 inch streaming magnetic tape cartridge (Sun QIC-24) in UNIX tar format. Alternate distribution media and formats are available upon request. This program was developed in 1992.

Mccluney, K.

1994-01-01

270

Enhancing the Real-Time Capability of the Linux Kernel  

Microsoft Academic Search

Linux has become one of the most popular UNIX operating systems. Commercial support for Linux and adoption of Linux in real world applications have now started to emerge. Some of the applications have strict real-time requirements. We discuss how to make Linux a real-time operating system. The real-time capability is achieved by three new kernel mechanisms. We port a microtimer

Yu-chung Wang; Kwei-jay Lin

1998-01-01

271

Real Time RF Simulator (RTS) and Control.  

National Technical Information Service (NTIS)

The multi-cavity RTS allows LLRF algorithm development and lab testing prior to commissioning with real cavities and cryomodules. The RTS is a valuable tool since it models the functions, errors and disturbances of real RF systems. The advantage of a RTS ...

A. Vignoni C. Armiento G. Cancelo K. Treptow T. Zmuda

2008-01-01

272

Real-Time Dosimetry for Radiobiology Experiments Using 25 MeV LINAC  

SciTech Connect

The next generation of radiobiology research requires increasingly more complex radiation sources to address questions ranging from the effects of space-based radiation to the influence of dose rate on biological systems. The Idaho Accelerator Center (IAC) has developed a radiobiology research facility to address some of these questions. The irradiation challenge is to deliver stable and reproducible conditions of high dose rate with well-controlled beam uniformity, dose, and dose rate under controlled temperature. In this work, we used a 25 MeV modified medical grade linear accelerator (LINAC) to obtain a high and adjustable electron dose rate. To overcome electron beam drift we used a collimator that both assisted the LINAC operator to steer the beam and ensured that regardless of beam drift, only the fixed collimated beam would irradiate the specimens. In addition, we utilized a beam flattener to keep the beam variation as low as 3% at 2.5 cm from the beam's center, and 1% variation between the simultaneously irradiated sample tubes. We also demonstrated that a segmented Faraday 'cup'(FC) array provides a useful real-time beam scanning and monitoring system, and is promising for implementing real-time dosimetry and control.

Mestari, Mohammed A.; Naeem, Syed F. [Department of Physics, Idaho State University, 921 S. 8th St., MS 8106, Pocatello, ID 83209 (United States); Wells, Douglas P.; Hunt, Alan [Idaho Accelerator Center, Idaho State University, 921 S. 8th St., MS 8263, Pocatello, ID 83209 (United States); Department of Physics, Idaho State University, 921 S. 8th St., MS 8106, Pocatello, ID 83209 (United States); DeVeaux, Linda C. [Idaho Accelerator Center, Idaho State University, 921 S. 8th St., MS 8263, Pocatello, ID 83209 (United States); Department of Biological Sciences, Idaho State University, 921 S. 8th St., MS 8007, Pocatello, ID 83209 (United States)

2009-03-10

273

Real-Time Dosimetry for Radiobiology Experiments Using 25 MeV LINAC  

NASA Astrophysics Data System (ADS)

The next generation of radiobiology research requires increasingly more complex radiation sources to address questions ranging from the effects of space-based radiation to the influence of dose rate on biological systems. The Idaho Accelerator Center (IAC) has developed a radiobiology research facility to address some of these questions. The irradiation challenge is to deliver stable and reproducible conditions of high dose rate with well-controlled beam uniformity, dose, and dose rate under controlled temperature. In this work, we used a 25 MeV modified medical grade linear accelerator (LINAC) to obtain a high and adjustable electron dose rate. To overcome electron beam drift we used a collimator that both assisted the LINAC operator to steer the beam and ensured that regardless of beam drift, only the fixed collimated beam would irradiate the specimens. In addition, we utilized a beam flattener to keep the beam variation as low as 3% at 2.5 cm from the beam's center, and 1% variation between the simultaneously irradiated sample tubes. We also demonstrated that a segmented Faraday ``cup'' (FC) array provides a useful real-time beam scanning and monitoring system, and is promising for implementing real-time dosimetry and control.

Mestari, Mohammed A.; Wells, Douglas P.; Deveaux, Linda C.; Hunt, Alan; Naeem, Syed F.

2009-03-01

274

Real-Time 3D Visualization  

NASA Technical Reports Server (NTRS)

Butler Hine, former director of the Intelligent Mechanism Group (IMG) at Ames Research Center, and five others partnered to start Fourth Planet, Inc., a visualization company that specializes in the intuitive visual representation of dynamic, real-time data over the Internet and Intranet. Over a five-year period, the then NASA researchers performed ten robotic field missions in harsh climes to mimic the end- to-end operations of automated vehicles trekking across another world under control from Earth. The core software technology for these missions was the Virtual Environment Vehicle Interface (VEVI). Fourth Planet has released VEVI4, the fourth generation of the VEVI software, and NetVision. VEVI4 is a cutting-edge computer graphics simulation and remote control applications tool. The NetVision package allows large companies to view and analyze in virtual 3D space such things as the health or performance of their computer network or locate a trouble spot on an electric power grid. Other products are forthcoming. Fourth Planet is currently part of the NASA/Ames Technology Commercialization Center, a business incubator for start-up companies.

1997-01-01

275

Real-time sensing of optical alignment  

NASA Technical Reports Server (NTRS)

The Large Deployable Reflector and other future segmented optical systems may require autonomous, real-time alignment of their optical surfaces. Researchers have developed gratings located directly on a mirror surface to provide interferometric sensing of the location and figure of the mirror. The grating diffracts a small portion of the incident beam to a diffractive focus where the designed diagnostics can be performed. Mirrors with diffraction gratings were fabricated in two separate ways. The formation of a holographic grating over the entire surface of a mirror, thereby forming a Zone Plate Mirror (ZPM) is described. Researchers have also used computer-generated hologram (CGH) patches for alignment and figure sensing of mirrors. When appropriately illuminated, a grid of patches spread over a mirror segment will yield a grid of point images at a wavefront sensor, with the relative location of the points providing information on the figure and location of the mirror. A particular advantage of using the CGH approach is that the holographic patches can be computed, fabricated, and replicated on a mirror segment in a mass production 1-g clean room environment.

Stier, Mark T.; Wissinger, Alan B.

1988-01-01

276

Real-time beamforming synthetic aperture radar  

NASA Astrophysics Data System (ADS)

This paper discusses the concept and design of a real-time Digital Beamforming Synthetic Aperture Radar (DBSAR) for airborne applications which can achieve fine spatial resolutions and wide swaths. The development of the DBSAR enhances important scientific measurements in Earth science, and serves as a prove-of-concept for planetary exploration missions. A unique aspect of DBSAR is that it achieves fine resolutions over large swaths by synthesizing multiple cross-track beams simultaneously using digital beamforming techniques. Each beam is processed using SAR algorithms to obtain the fine ground resolution without compromising fine range and azimuth resolutions. The processor uses an FPGA-based architecture to implement digital in-phase and quadrature (I/Q) demodulation, beamforming, and range and azimuth compression. The DBSAR concept will be implemented using the airborne L-Band Imaging Scatterometer (LIS) on board the NASA P3 aircraft. The system will achieve ground resolutions of less than 30 m and swaths of 10 km from an altitude of 8 km.

Rincon, Rafael; Hildebrand, Peter; Hilliard, Lawrence; Bradley, Damon; Krnan, Luko; Sheikh, Salman; Lucey, Jared

2006-10-01

277

Real time radiation measurements in space  

NASA Astrophysics Data System (ADS)

Radiation composed of energetic electrons, protons, photons, and galactic cosmic rays will be experienced by all space missions and may have effects on radiation sensitive electronic components and biological specimens. Radiation issues of interest to microgravity and biological experiments are discussed and the design of a new direct reading electronic radiation monitoring system is described. The proposed system consists of a radiation sensitive metal oxide semiconductor field effect transistor (MOSFET) specially designed to respond to ionizing radiation. On exposure to radiation, a permanent charge is stored in the MOSFET's insulating oxide, altering the device's electrical characteristics in a manner directly proportional to the dose exposed. A simple circuit reads the MOSFET's cumulative dose, making it possible to obtain real-time measurements and store the data or transfer the data to an earth station. Tests have shown that the MOSFET dosimeter shows a linear response up to at least 30,000 centiGray at a resolution of 0.1 centiGray. The MOSFET dosimetry system will be installed on the European Space Agency's ARTEP satellite scheduled for launch in November 1991.

Thomson, I.; Mackay, G.

278

High sensitivity real-time NVR monitor  

NASA Technical Reports Server (NTRS)

A real time non-volatile residue (NVR) monitor, which utilizes surface acoustic wave (SAW) resonators to detect molecular contamination in a given environment. The SAW resonators operate at a resonant frequency of approximately 200 MHz-2,000 MHz which enables the NVR monitor to detect molecular contamination on the order of 10.sup.-11 g-cm.sup.-2 to 10.sup.-13 g-cm.sup.2. The NVR monitor utilizes active temperature control of (SAW) resonators to achieve a stable resonant frequency. The temperature control system of the NVR monitor is able to directly heat and cool the SAW resonators utilizing a thermoelectric element to maintain the resonators at a present temperature independent of the environmental conditions. In order to enable the direct heating and cooling of the SAW resonators, the SAW resonators are operatively mounted to a heat sink. In one embodiment, the heat sink is located in between the SAW resonators and an electronic circuit board which contains at least a portion of the SAW control electronics. The electrical leads of the SAW resonators are connected through the heat sink to the circuit board via an electronic path which prevents inaccurate frequency measurement.

Bowers, William D. (Inventor); Chuan, Raymond L. (Inventor)

1997-01-01

279

Real-Time Accumulative Computation Motion Detectors  

PubMed Central

The neurally inspired accumulative computation (AC) method and its application to motion detection have been introduced in the past years. This paper revisits the fact that many researchers have explored the relationship between neural networks and finite state machines. Indeed, finite state machines constitute the best characterized computational model, whereas artificial neural networks have become a very successful tool for modeling and problem solving. The article shows how to reach real-time performance after using a model described as a finite state machine. This paper introduces two steps towards that direction: (a) A simplification of the general AC method is performed by formally transforming it into a finite state machine. (b) A hardware implementation in FPGA of such a designed AC module, as well as an 8-AC motion detector, providing promising performance results. We also offer two case studies of the use of AC motion detectors in surveillance applications, namely infrared-based people segmentation and color-based people tracking, respectively.

Fernandez-Caballero, Antonio; Lopez, Maria Teresa; Castillo, Jose Carlos; Maldonado-Bascon, Saturnino

2009-01-01

280

Real-time adaptive radiometric compensation.  

PubMed

Recent radiometric compensation techniques make it possible to project images onto colored and textured surfaces. This is realized with projector-camera systems by scanning the projection surface on a per-pixel basis. Using the captured information, a compensation image is calculated that neutralizes geometric distortions and color blending caused by the underlying surface. As a result, the brightness and the contrast of the input image is reduced compared to a conventional projection onto a white canvas. If the input image is not manipulated in its intensities, the compensation image can contain values that are outside the dynamic range of the projector. These will lead to clipping errors and to visible artifacts on the surface. In this article, we present an innovative algorithm that dynamically adjusts the content of the input images before radiometric compensation is carried out. This reduces the perceived visual artifacts while simultaneously preserving a maximum of luminance and contrast. The algorithm is implemented entirely on the GPU and is the first of its kind to run in real-time. PMID:17993705

Grundhöfer, Anselm; Bimber, Oliver

2008-01-01

281

Real time interactive animation for articulated bodies  

NASA Astrophysics Data System (ADS)

In interactive environments including computer games and virtual reality applications, we have increased the need for interactive control of articulated body motions. Recently, physically based methods including constrained dynamics techniques are introduced to this area, in order to produce more realistic animation sequences. However, they are hard to achieve real-time control of articulated bodies, due to their heavy computations. In this paper, we present a procedural method for interactive animation of articulated bodies. In our method, each object of the constrained body is first moved according to their physical properties and external forces, without considering any constraints. Then, the locations of objects are adjusted to satisfy given constraints. Through adapting this two-stage approach, we have avoided the solving of large linear systems of equations, to finally achieve the interactive animation of articulated bodies. We also present a few example sequences of animations, which are interactively generated on PC platforms. This method can be easily applied to character animations in virtual environments.

Bae, HeeJung; Ryu, KwyanWoo

2002-07-01

282

Scheduling of real\\/non-real time services: adaptive EXP\\/PF algorithm  

Microsoft Academic Search

An efficient channel scheduler called the adaptive EXP\\/PF algorithm is proposed to provide real-time service with different QoS as well as a non-real time data services demanded by mobile users in an adaptive modulation and coding in time division multiplexing (AMC\\/TDM) systems. The adaptive EXP\\/PF algorithm guarantees transmission time delay bounds for real-time services as well as maximizes the system

Jong-Hun Rhee; J. M. Holtzman; Dong-Ku Kim

2003-01-01

283

Benchmarking real-time HEVC streaming  

NASA Astrophysics Data System (ADS)

Work towards the standardisation of High Efficiency Video Coding (HEVC), the next generation video coding scheme, is currently gaining pace. HEVC offers the prospect of a 50% improvement in compression over the current H.264 Advanced Video Coding standard (H.264/AVC). Thus far, work on HEVC has concentrated on improvements to the coding efficiency and has not yet addressed transmission in networks other than to mandate byte stream compliance with Annex B of H.264/AVC. For practical networked HEVC applications a number of essential building blocks have yet to be defined. In this work, we design and prototype a real-time HEVC streaming system and empirically evaluate its performance, in particular we consider the robustness of the current Test Model under Consideration (TMuC HM4.0) for HEVC to packet loss caused by a reduction in available bandwidth both in terms of decoder resilience and degradation in perceptual video quality. A NAL unit packetisation and streaming framework for HEVC encoded video streams is designed, implemented and empirically tested in a number of streaming environments including wired, wireless, single path and multiple path network scenarios. As a first step the HEVC decoder's error resilience is tested under a comprehensive set of packet loss conditions and a simple error concealment method for HEVC is implemented. Similarly to H.264 encoded streams, the size and distribution of NAL units within an HEVC stream and the nature of the NAL unit dependencies influences the packetisation and streaming strategies which may be employed for such streams. The relationships between HEVC encoding mode and the quality of the received video are shown under a wide range of bandwidth constraints. HEVC streaming is evaluated in both single and multipath network configuration scenarios. Through the use of extensive experimentation, we establish a comprehensive set of benchmarks for HEVC streaming in loss prone network environments. We show the visual quality reduction in terms of PSNR which results from a reduction in available bandwidth. To the best of our knowledge, this is the first time that such a fully functional streaming system for HEVC, together with the benchmark evaluation results, has been reported. This study will open up more timely research opportunities in this cutting edge area.

Nightingale, James; Wang, Qi; Grecos, Christos

2012-05-01

284

Real time monitoring of electroless nickel plating  

NASA Astrophysics Data System (ADS)

This work deals with the design and manufacturing of the heat and chemical resistant transducer case required for on-line immersion testing, experimental design, data acquisition and signal processing. Results are presented for several depositions with an accuracy of two ten-thousandths of an inch in coating thickness obtained. Monitoring the deposition rate of Electroless Nickel (EN) plating in-situ will provide measurement of the accurate dimensions of the component being plated, in real time. EN is used as for corrosion and wear protection for automotive an - Electroless Nickel (EN) plating is commonly used for corrosion and wear protection for automotive and aerospace components. It plates evenly and symmetrically, theoretically allowing the part to be plated to its final dimension. Currently the standard approach to monitoring the thickness of the deposited nickel is to remove the component from the plating bath and physically measure the part. This can lead to plating problems such as pitting, non-adhesion of the deposit and contamination of the plating solution. The goal of this research effort is to demonstrate that plating thickness can be rapidly and accurately measured using ultrasonic testing. Here a special housing is designed to allow immersion of the ultrasonic transducers directly into the plating bath. An FFT based signal processing algorithm was developed to resolve closely spaced echoes for precise thickness determination. The technique in this research effort was found to be capable of measuring plating thicknesses to within 0.0002 inches. It is expected that this approach will lead to cost savings in many EN plating operations.

Rains, Aaron E.; Kline, Ronald A.

2013-01-01

285

Towards Transactional Memory for Real-Time Systems  

Microsoft Academic Search

In this paper, we explore a new synchronization paradigm for real-time systems: transactional memory for real-time systems. Transactional memory is con- sidered as a solution for parallel programs on a shared memory chip multiprocessor. It simplifies the program- ming model and increases the average case throughput. However, in real-time systems we are interested in the worst-case execution time. In this

Martin Schoeberl; Bent Thomsen; Lone Leth Thomsen

286

Modechart: A Specification Language for Real-Time Systems  

Microsoft Academic Search

Present a specification language for real-time systems called Modechart. The semantics of Modechart is given in terms of real-time logic (RTL), which is especially amenable to reasoning about the absolute (real-time clock) timing of events. The semantics of Modechart has an important property that the translation of a Modechart specification into RTL formulas results in a hierarchical organization of the

Farnam Jahanian; Aloysius K. Mok

1994-01-01

287

A Linux-based Real-Time Operating System  

Microsoft Academic Search

This work describes the design, implementation, and possible applications of Real-Time Linux --- a hard real-time version of the Linux operating system. In this system, a standard time-sharing OS and a real-time executive run on the same computer. Interrupt controller emulation is used to guarantee a low maximum interrupt latency independently of the base system. The use of a one-shot

Michael Barabanov

1997-01-01

288

Application specific real-time microkernel in hardware  

Microsoft Academic Search

Real-time operating system kernels in embedded systems need to be configurable. Unfortunately many of today's commercial real-time kernels are monolithic. These optimized code packages are difficult to change and maintain. This is motivated mainly to achieve short response time and easy access of debugging information. To solve the drawbacks of the monolithic real-time kernels, the microkernel structure was introduced. The

Susanna Nordström; Lennart Lindh; Lars Johansson; Tobias Skoglund

2005-01-01

289

Improving Soft Real-Time Performance through Better Slack Reclaiming  

Microsoft Academic Search

Modern operating systems frequently support applica- tions with a variety of timing constraints including hard real-time, soft real-time, and best-effort. To guarantee performance, critical applications typically over-reser ve resources based on worst-case resource usage estimates, while others may reserve based on average-case or other estimates. When resources are fully subscribed, the perfor - mance of soft- and non-real-time applications depends

Caixue Lin; Scott A. Brandt

2005-01-01

290

Real-Time Wireless Data Acquisition System  

NASA Technical Reports Server (NTRS)

Current and future aerospace requirements demand the creation of a new breed of sensing devices, with emphasis on reduced weight, power consumption, and physical size. This new generation of sensors must possess a high degree of intelligence to provide critical data efficiently and in real-time. Intelligence will include self-calibration, self-health assessment, and pre-processing of raw data at the sensor level. Most of these features are already incorporated in the Wireless Sensors Network (SensorNet(TradeMark)), developed by the Instrumentation Group at Kennedy Space Center (KSC). A system based on the SensorNet(TradeMark) architecture consists of data collection point(s) called Central Stations (CS) and intelligent sensors called Remote Stations (RS) where one or more CSs can be accommodated depending on the specific application. The CS's major function is to establish communications with the Remote Stations and to poll each RS for data and health information. The CS also collects, stores and distributes these data to the appropriate systems requiring the information. The system has the ability to perform point-to-point, multi-point and relay mode communications with an autonomous self-diagnosis of each communications link. Upon detection of a communication failure, the system automatically reconfigures to establish new communication paths. These communication paths are automatically and autonomously selected as the best paths by the system based on the existing operating environment. The data acquisition system currently under development at KSC consists of the SensorNet(TradeMark) wireless sensors as the remote stations and the central station called the Radio Frequency Health Node (RFHN). The RFF1N is the central station which remotely communicates with the SensorNet(TradeMark) sensors to control them and to receive data. The system's salient feature is the ability to provide deterministic sensor data with accurate time stamps for both time critical and non-time critical applications. Current wireless standards such as Zigbee(TradeMark) and Bluetooth(Registered TradeMark) do not have these capabilities and can not meet the needs that are provided by the SensorNet technology. Additionally, the system has the ability to automatically reconfigure the wireless communication link to a secondary frequency if interference is encountered and can autonomously search for a sensor that was perceived to be lost using the relay capabilities of the sensors and the secondary frequency. The RFHN and the SensorNet designs are based on modular architectures that allow for future increases in capability and the ability to expand or upgrade with relative ease. The RFHN and SensorNet sensors .can also perform data processing which forms a distributed processing architecture allowing the system to pass along information rather than just sending "raw data points" to the next higher level system. With a relatively small size, weight and power consumption, this system has the potential for both spacecraft and aircraft applications as well as ground applications that require time critical data.

Valencia, Emilio J.; Perotti, Jose; Lucena, Angel; Mata, Carlos

2007-01-01

291

Real time UAV autonomy through offline calculations  

NASA Astrophysics Data System (ADS)

Two or three dimensional mission plans for a single or a group of hover or fixed wing UAVs are generated. The mission plans can largely be separated into seven main parts. Firstly, the Region Growing algorithm is used to generate a map from 2D or 3D images. Secondly, the map is analyzed to separate each blocks using vertices of blocks and seven filtering steps. Thirdly, the Trapezoidal map algorithm is used to convert the map into a traversability graph. Fourthly, this process also filters out paths that are not traversable. That is, nodes located inside the blocks and too closely located nodes are filtered out. Fifthly, the Dijkstra algorithm is used to calculate the shortest path from a starting point to a goal point. Sixthly, the 1D Optimal Control algorithm is applied to manipulate the velocity and acceleration of the UAVs efficiently. Basically, the UAVs accelerates at one graph node and maintains a constant velocity and decelerates before reaching the next graph node. Lastly, Traveling Salesman Problem Method (TSP) algorithm is used to calculate the shortest path to search the whole region. After this discretization of space and time, it becomes possible to solve several autonomous mission planning problems. We focus on one of the most difficult problems: coordinated search. This is a multiple Traveling Salesman Problem (mTSP). We solve it by decomposing the search region and solving TSPs for each vehicle searching a sub-region. The mTSP is generally used when there are more than one salesman is used. In addition to the four main parts, there are three minor parts which support the main parts. Firstly, Target Detection algorithm is generated to detect a target located near the UAVs' path. A picture of the desired target is inserted into the algorithm before UAVs launch. Using the Scale-Invariant Transform Feature (SIFT) algorithm, a target with a specific shape can be detected. Secondly, Tracking algorithm is generated to manipulate UAVs to follow targets. Once one or several targets are detected, UAVs near the target are manipulated to approach to the target. If the number of detected targets is more than one, UAVs are evenly grouped to track targets. After a specific period of time, UAVs hand off and continue their original tasks. Thirdly, Emergency algorithm is generated to avoid losses of UAVs when UAVs have system failures. If one UAV is out of fuel or control during the mission, the Emergency algorithm brings the malfunctioning UAV to the point of departure and let the rest UAVs to continue an aerial reconnaissance. An UAV which finishes its task the earliest will continue to search a region which the failed UAV is supposed to search. In addition, Emergency algorithm prevents UAVs colliding into each other by using emergency altitude. Overall, the framework developed here facilitates the solution of several mission planning problems. The robustness built into our discretization of space and time permits feedback corrections on real-time to vehicle trajectories. The library of off-line solutions proposed and developed here minimizes computational overhead during operations.

Jung, Sunghun

292

Garbage Collector Scheduling in Dynamic, Multiprocessor Real-Time Systems  

Microsoft Academic Search

We consider garbage collection (GC) in dynamic, multiprocessor real-time systems. We consider the time-based, concurrent GC approach and focus on real-time scheduling to obtain mutator timing assurances, despite memory allocation and garbage collection. We present a scheduling algorithm called GCMUA. The algorithm considers mutator activities that are subject to time\\/utility function time constraints, stochastic execution-time and memory demands, and overloads.

Hyeonjoong Cho; Binoy Ravindran; Chewoo Na

2009-01-01

293

Implementing a General Real-Time Scheduling Framework in the RED-Linux Real-Time Kernel  

Microsoft Academic Search

Many scheduling paradigms have been studied for real- time applications and real-time communication network. Among them, the most commonly used paradigms include priority-driven, time-driven and share-driven paradigms. In this paper, we present a general scheduling framework which is designed to integrate these paradigms in one frame- work. The framework is implemented in our real-time extension of the Linux kernel, RED-Linux.

Yu-chung Wang; Kwei-jay Lin

1999-01-01

294

Real-time 3D model acquisition  

Microsoft Academic Search

The digitization of the 3D shape of real objects is a rapidly expanding field, with applications in entertainment, design, and archaeology. We propose a new 3D model acquisition system that permits the user to rotate an object by hand and see a continuously-updated model as the object is scanned. This tight feedback loop allows the user to find and fill

Szymon Rusinkiewicz; Olaf A. Hall-Holt; Marc Levoy

2002-01-01

295

Performance Specifications and Metrics for Adaptive Real-Time Systems  

Microsoft Academic Search

While early research on real-time computing was concerned with guaranteeing avoidance of undesirabl e effects such as overload and deadline misses, adapt ive real-time systems are designed to handle such effec ts dynamically. Various research efforts have addresse d the characterization and improvement of the dynamic behavior of real-time systems. However, to the auth ors' knowledge, no unified framework exists

Chenyang Lu; John A. Stankovic; Tarek F. Abdelzaher; Gang Tao; Sang Hyuk Son; Michael Marley

2000-01-01

296

Value of real-time information in competitive generation markets  

Microsoft Academic Search

This paper presents an analysis of the value of real-time information response. The paper describes how rapid response to market conditions, enabled by access to real-time market information (where real-time is on the order of minutes down to seconds), can impact peak electricity demand. Through rapid response from generation supply during peak demand periods, an effective average increase in generation

Angela S. Chuang

2002-01-01

297

Scheduling of hard real-time garbage collection  

Microsoft Academic Search

Automatic memory management or garbage collection greatly simplifies development of large systems. However, garbage collection is usually not used in real-time systems due to the unpredictable temporal behavior of current implemen- tations of a garbage collector. In this paper we propose a real-time garbage collector that can be scheduled like a normal real-time thread with a deadline monotonic as- signed

Martin Schoeberl

2010-01-01

298

Building Soft Real-Time Monitors Based on Software Reuse  

Microsoft Academic Search

This paper proposes an integration framework to develop real-time monitor programs based on software reuse. A custom-made real-time monitor program can be quickly built by integrating existing monitor programs in commercial operating systems, where limited real-time system and programming support is provided. We consider issues related to the software control, output re-processing, data age, and interactivities of program executions. The

Mei-Ling Hsu; Tei-Wei Kuo

1998-01-01

299

Quantification using real-time PCR technology: applications and limitations  

Microsoft Academic Search

The introduction of real-time PCR technology has significantly improved and simplified the quantification of nucleic acids, and this technology has become an invaluable tool for many scientists working in different disciplines. Especially in the field of molecular diagnostics, real-time PCR-based assays have gained favour in the recent past. However, the wide use of real-time PCR methods has also highlighted some

Dieter Klein

2002-01-01

300

An old-fashioned recipe for real time  

Microsoft Academic Search

Traditional methods for specifying and reasoning about concurrent systems work for real-time systems. Using TLA (the temporal logic of actions), we illustrate how they work with the examples of a queue and of a mutual-exclusion protocol. In general, two problems must be addressed: avoiding the real-time programming version of Zeno's paradox, and coping with circularities when composing real-time assumption\\/guarantee specifications.

Martín Abadi; Leslie Lamport

1994-01-01

301

Real-time and postprocessing holographic effects in dichromated pullulan  

NASA Astrophysics Data System (ADS)

Experimental results concerning both real-time and postprocessing (after-development) behavior of a novel photosensitive material, dichromate-sensitized pullulan (DCP), are investigated. The exposure mechanism and possibilities for controlling holographic grating properties are discussed. We have shown that it is possible to maximize the diffraction efficiency of interference gratings after development by controlling diffraction efficiency in real time. Stronger real-time effects of DCP compared with those of dichromated gelatin are achieved.

Savic, Svetlana; Pantelic, Dejan; Jakovijevic, Dragica

2002-08-01

302

RTP: A Transport Protocol for Real-Time Applications  

Microsoft Academic Search

This memorandum describes RTP, the real-time transport protocol. RTP provides end-to-end network transport functions suitable for applications transmitting real-time data, such as audio, video or simulation data, over multicast or unicast network services. RTP does not address resource reservation and does not guarantee quality-of-service for real-time services. The data transport is augmented by a control protocol (RTCP) to allow monitoring

H. Schulzrinne; S. Casner; R. Frederick; V. Jacobson

2001-01-01

303

Diverse Soft Real-Time Processing in an Integrated System  

Microsoft Academic Search

The simple notion of soft real-time processing has frac- tured into a spectrum of diverse soft real-time types with a variety of different resource and time constraints. Sched- ulers have been developed for each of these types, but these are essentially point solutions in the space of soft real-ti me and no single scheduler has previously been offered that can

Caixue Lin; Tim Kaldewey; Anna Povzner; Scott A. Brandt

2006-01-01

304

Improved real-time scheduling for periodic tasks on multiprocessors  

Microsoft Academic Search

Due to increasing numbers of real-time high-performance applications like control systems, autonomous robots, financial systems, scheduling these real-time applications on HPC resources has become an important problem. This paper presents a novel real-time multiprocessor scheduling algorithm, called Notional Approximation for Balancing Load Residues (NABLR), which heuristically selects tasks for execution by taking into account their residual loads and laxities. The

Prapaporn Rattanatamrong; Jose A. B. Fortes

2011-01-01

305

Feedback Control Real-Time Scheduling in ORB Middleware  

Microsoft Academic Search

Existing real-time ORB middleware standards such as RT-CORBA do not adequately address the challenges of 1) providing robust performance guaran- tees portably across different platforms, and 2) manag- ing unpredictable workload. To overcome this limita- tion, we have developed software called FCS\\/nORB that integrates a Feedback Control real-time Schedul- ing (FCS) service with the nORB small-footprint real- time ORB designed

Chenyang Lu; Xiaorui Wang; Christopher D. Gill

2003-01-01

306

Measuring OS support for real-time CORBA ORBs  

Microsoft Academic Search

The paper compares and evaluates the suitability of real time operating systems, VxWorks and LynxOS, and general purpose operating systems with real time extensions, Windows NT, Solaris, and Linux, for real time ORB middleware. While holding the hardware and ORB constant, we vary these operating systems and measure platform-specific variations in context switching overhead and priority inversions. Our findings illustrate

David L. Levine; Sergio Flores-Gaitan; Christopher D. Gill; Douglas C. Schmidt

1999-01-01

307

Real time power system simulation using RTDS and NI PXI  

Microsoft Academic Search

Real time simulation is becoming an essential simulation environment for engineering design, especially in power systems. This paper discusses two real time simulators applied to power system simulation: real time digital simulator (RTDS) and National Instruments-PXI (PCI eXtensions for Instrumentation). RTDS is an efficient tool for the design, development, and testing of power system and its components. NI-PXI is a

Ankush Saran; Sunil K. Palla; Anurag K. Srivastava; N. N. Schulz

2008-01-01

308

Scheduling Real-time Transactions: a Performance Evaluation  

Microsoft Academic Search

Ivfanaging transactions with real-time requirements presents many new problems. In this paper we focus on two: How can we schedule transactions with deadlines? How do the real-time constraints affect concurrency con- trol? We describe a new group of algorithms for scheduling real-time transactions which produce serialix- able schedules. We present a model for scheduling tmn- sactions with deadlines on a

Robert K. Abbott; Hector Garcia-molina

1988-01-01

309

Environmental Simulation of Real-Time Systems with Nested Interrupts  

Microsoft Academic Search

Interrupts are important aspects of real-time embedded systems to handle events in time. When there exist nested in- terrupts in a real-time system, and an urgent interrupt is al- lowed to preempt the current interrupt handling, the design and analysis of the system become difficult due to the lack of appropriate behavioral models. This paper proposes a compositional model for

Guoqiang Li; Shoji Yuen; Masakazu Adachi

2009-01-01

310

A real-time simulation facility for astronomical adaptive optics  

NASA Astrophysics Data System (ADS)

In this paper we introduce the concept of real-time hardware-in-the-loop simulation for astronomical adaptive optics, and present the case for the requirement for such a facility. This real-time simulation, when linked with an adaptive optics real-time control system, provides an essential tool for the validation, verification and integration of the Extremely Large Telescope real-time control systems prior to commissioning at the telescope. We demonstrate that such a facility is crucial for the success of the future extremely large telescopes.

Basden, Alastair

2014-02-01

311

Enhancing Real-Time CORBA Predictability and Performance  

Microsoft Academic Search

\\u000a Distributed real-time and embedded (DRE) applications possess stringent quality of service (QoS) requirements, such as low\\u000a latency, bounded jitter, and high throughput. An increasing number of DRE applications are developed using QoS-enabled middleware,\\u000a such as Real-time CORBA and the Real-time Specification for Java (RTSJ), to ensure predictable end-to-end QoS. Real-time CORBA\\u000a is an open middleware standard that allows DRE applications

Arvind S. Krishna; Douglas C. Schmidt; Krishna Raman; Raymond Klefstad

2003-01-01

312

PDE based Video Compression in Real Time  

Microsoft Academic Search

Abstract We implement a video codec with a decompression scheme based on image inpainting using dierent,kinds of diusion,models. The arising PDEs are solved by an ecient,multigrid solver in case of linear homogeneous diusion,and by a multilevel scheme applying inexact lagged diusivity,in case of nonlinear isotropic and anisotropic diusion.,We consider real world and medical data sets, and show that it is

H. Kostler; M. Sturmer; Ch. Freundl; U. Rude

313

RT-EP: Real-Time Ethernet Protocol for Analyzable Distributed Applications on a Minimum Real-Time POSIX Kernel  

Microsoft Academic Search

This paper presents the design and implementation of RT- EP (Real-Time Ethernet Protocol), which is a software- based token-passing Ethernet protocol for multipoint com- munications in real-time applications, that does not require any modification to existing Ethernet hardware. This proto- col allows the designer to model and analyze the real-time application using it, because it is based on fixed priorities

José María Martínez; Michael González Harbour; J. Javier Gutiérrez

314

Laboratory tools for DSP based real-time simulation  

Microsoft Academic Search

Real-time simulation is proving very useful in simulating complex and expensive systems using the high performance multi-processors. It has many applications in the area of testing of controllers and protection systems under real-field like situations. In this project, an effort has been made to prepare a low-cost system to carry out real-time simulation in an educational laboratory setting. The system

Rashesh P. Mehta; Mahesh B. Patil; Mukul Chandorkar

2011-01-01

315

Symbolic Model Checking for Real-time Systems  

Microsoft Academic Search

. We describe finite-state programs over real-numbered time in a guardedcommandlanguage with real-valued clocks or, equivalently, as finite automata withreal-valued clocks. Model checking answers the question which states of a real-timeprogram satisfy a branching-time specification (given in an extension of CTL with clockvariables). We develop an algorithm that computes this set of states symbolically as afixpoint of a functional on

Thomas A. Henzingert; Xavier Nicollin; Joseph Sifakis; Sergio Yovine

1992-01-01

316

A real-time photogrammetry system based on embedded architecture  

NASA Astrophysics Data System (ADS)

In order to meet the demand of real-time spatial data processing and improve the online processing capability of photogrammetric system, a kind of real-time photogrammetry method is proposed in this paper. According to the proposed method, system based on embedded architecture is then designed: using FPGA, ARM+DSP and other embedded computing technology to build specialized hardware operating environment, transplanting and optimizing the existing photogrammetric algorithm to the embedded system, and finally real-time photogrammetric data processing is realized. At last, aerial photogrammetric experiment shows that the method can achieve high-speed and stable on-line processing of photogrammetric data. And the experiment also verifies the feasibility of the proposed real-time photogrammetric system based on embedded architecture. It is the first time to realize real-time aerial photogrammetric system, which can improve the online processing efficiency of photogrammetry to a higher level and broaden the application field of photogrammetry.

Zheng, S. Y.; Gui, L.; Wang, X. N.; Ma, D.

2014-06-01

317

Real-time fault diagnosis for propulsion systems  

NASA Technical Reports Server (NTRS)

Current research toward real time fault diagnosis for propulsion systems at NASA-Lewis is described. The research is being applied to both air breathing and rocket propulsion systems. Topics include fault detection methods including neural networks, system modeling, and real time implementations.

Merrill, Walter C.; Guo, Ten-Huei; Delaat, John C.; Duyar, Ahmet

1991-01-01

318

Towards Runtime Monitoring in Real-Time Systems  

Microsoft Academic Search

In this paper we present the state of our work on runtime monitoring for real-time systems: a way to observe system behavior online without unpredictably disturbing real-time properties. We discuss generic requirements to achieve these properties wherefrom we deduce our monitoring frame- work architecture. We describe this architecture in detail and discuss several challenges for our implemen- tation called Ferret.

Martin Pohlack; Bjorn Dobel; Adam Lackorzynski

319

Triggered Real-Time Databases with Consistency Constraints  

Microsoft Academic Search

Real-time database systems incorporate the notion of a deadline into the database system model. USU- ally, deadlines are associated with transactions, and the system attempts to execute a given set of trans- actions so as to both meet the deadlines and ensure the database consistency. This paper presents an al- ternative model of real-time database processing in which deadlines are

Henry F. Korth; Nandit Soparkar; Abraham Silberschatz

1990-01-01

320

Teaching real-time with a scheduler simulator  

Microsoft Academic Search

In this paper we describe a scheduler simulator for real-time tasks, RTsim, that can be used as a tool to teach real-time scheduling algorithms. It simulates a variety of preprogrammed scheduling policies for single and multiprocessor systems and simple algorithm variants introduced by its user. Using RTsim students can conduct experiments that will allow them to understand the effects of

Aleardo Manacero Jr; Marcelo B. Miola; Viviane A. Nabuco

2001-01-01

321

Distributed scheduling for real-time railway traffic control  

Microsoft Academic Search

The increase of railway traffic efficiency and flex- ibility requires new real-time scheduling and control methods. New charter trains have to be added continuously without disturbing the other (periodic) train moves or decreasing the safety conditions. A distributed method to schedule new trains such that their real-time constraints are fulfilled is prese nted. The trains have timelines to meet and

Tiberiu Letia; Mihai Hulea; Radu Miron

2008-01-01

322

Real-time lens distortion correction using texture mapping  

Microsoft Academic Search

Optical lens systems suffer from non-linear radial distortion. Applications such as computer vision and medical imaging require distortion compensation for the accurate location, registration and measurement of image features. While in many applications distortion correction may be applied offline, a real-time capability is desirable for systems that interact with the environment or with a user in real time. The construction

Michael R. Bax

2003-01-01

323

Ecohydraulic-driven real-time control of stormwater basins  

NASA Astrophysics Data System (ADS)

We evaluate the potential of ecohydraulic-driven real-time control of stormwater basins.We conduct a simulation study focusing on the removal efficiency of particulates.Real-time control is an effective solution for reducing the suspended solids discharge.A parallel experimental study confirmed the obtained removal improvements.

Muschalla, Dirk; Vallet, Bertrand; Anctil, François; Lessard, Paul; Pelletier, Geneviève; Vanrolleghem, Peter A.

2014-04-01

324

Multicolor Combinatorial Probe Coding for Real-Time PCR  

Microsoft Academic Search

The target volume of multiplex real-time PCR assays is limited by the number of fluorescent dyes available and the number of fluorescence acquisition channels present in the PCR instrument. We hereby explored a probe labeling strategy that significantly increased the target volume of real-time PCR detection in one reaction. The labeling paradigm, termed “Multicolor Combinatorial Probe Coding” (MCPC), uses a

Qiuying Huang; Linlin Zheng; Yumei Zhu; Jiafeng Zhang; Huixin Wen; Jianwei Huang; Jianjun Niu; Xilin Zhao; Qingge Li

2011-01-01

325

ANIMAC: a multiprocessor architecture for real time computer animation  

Microsoft Academic Search

Advances in integrated circuit technology have been largely responsible for the growth of the computer graphic industry. This technology promises additional growth through the remainder of the century. This dissertation addresses how this future technology can be harnessed and used to construct very high performance real-time computer graphics systems. A new architecture is proposed for real-time animation engines. The ANIMAC

Daniel S. Whelan

1985-01-01

326

Real-time observation of electrical vortex core switching  

NASA Astrophysics Data System (ADS)

A single vortex-core switching induced by current injection into a ferromagnetic disk is detected in real time using a three-terminal device with the tunneling magnetoresistance junction. The real time observation reveals that the electrical core switching is completed within a few 100 ps. It is also found that the core switching takes place at the specific positions inside the disk.

Nakano, Kunihiro; Tanabe, Kenji; Hiramatsu, Ryo; Chiba, Daichi; Ohshima, Norikazu; Kasai, Shinya; Sato, Tomonori; Nakatani, Yoshinobu; Sekiguchi, Koji; Kobayashi, Kensuke; Ono, Teruo

2013-02-01

327

COMPUTER-CONTROLLED, REAL-TIME AUTOMOBILE EMISSIONS MONITORING SYSTEM  

EPA Science Inventory

A minicomputer controlled automotive emissions sampling and analysis system (the Real-Time System) was developed to determine vehicular modal emissions over various test cycles. This data acquisition system can sample real-time emissions at a rate of 10 samples/s. A buffer utiliz...

328

Physically Based Real-Time Translucency for Leaves  

Microsoft Academic Search

This paper presents a new shading model for real-time rendering of plant leaves that reproduces all important attributes of a leaf and allows for a large number of leaves to be shaded. In particular, we use a physically based model for accurate subsurface scattering on the translucent side of directly lit leaves. For real-time rendering of this model, we formulate

Ralf Habel; Alexander Kusternig; Michael Wimmer

2007-01-01

329

Real-Time Data Fusion in the Intensive Care Unit  

Microsoft Academic Search

A description is given of the process trellis, a domain- and hardware-independent software architecture. Its usefulness in building the Intelligent Cardiovascular Monitor, a real-time clinical decision-support system whose 'paving-stone' interface gives a clinician an instantaneous overview of a patient's status, is demonstrated. Issues of parallelism, real-time operation, and visualization are discussed.

Michael Factor; David H. Gelernter; Craig E. Kolb; Perry L. Miller; Dean F. Sittig

1991-01-01

330

IPS Real-Time Space Weather Status Panel  

NSDL National Science Digital Library

The IPS (Ionospheric Prediction Service) Real-Time Space Weather Status Panel, an agency of the Australian government, offers this collection of real-time space weather data. Available here are different types of up-to-date data for solar conditions, ionospheric conditions, and geomagnetic conditions.

331

Real-time extracellular measurement of neurotransmitters in conscious sheep  

Microsoft Academic Search

Measurements of neurotransmitters in conscious animals have been restrictive in real-time. The use of specific enzymes within an amperometric probe, based upon a microdialysis membrane, may overcome some of these problems. I report the use of such a probe, with different perfusions of enzymes, to allow real-time measurement of glutamate, catecholamines and indoleamines, in conscious animals. At an adjacent site

Christian J Cook

1997-01-01

332

The Use of Real Time Computers for Inventory Control.  

National Technical Information Service (NTIS)

A real-time system provides immediate access to information stored in the computer by operating personnel throughout the organization. The purpose of this thesis is to analyze existing and proposed real-time inventory control systems in order to determine...

D. D. Sharp

1964-01-01

333

Statistical analysis of real-time PCR data  

Microsoft Academic Search

Background: Even though real-time PCR has been broadly applied in biomedical sciences, data processing procedures for the analysis of quantitative real-time PCR are still lacking; specifically in the realm of appropriate statistical treatment. Confidence interval and statistical significance considerations are not explicit in many of the current data analysis approaches. Based on the standard curve method and other useful data

Joshua S. Yuan; Ann Reed; Feng Chen; C. Neal Stewart Jr.

2006-01-01

334

Directing Intelligent Digital Actor with Real-Time Motion Planning  

Microsoft Academic Search

Automatic motion generation for digital actors under real-time user control is a challenging problem for vir- tual environment applications such as on-line games. Despite many advances have been made in the past few years, most systems cannot generate full humanoid mo- tions in real time on an uneven terrain cluttered with obstacles of various heights. In this paper, we propose

Tsai-Yen Li

335

Fair Real-Time Traffic Scheduling over a Wireless LA  

Microsoft Academic Search

Unpredictable wireless channel errors may cause appli- cations with real-time traffic to receive degraded quality of services due to packet losses. In the presence of such errors, a challenging problem is how to schedule packets to achieve fairness among real-time flows and to maximize the over- all system throughput simultaneously. We capture fairness by minimizing the maximumdegradation in service over

Maria Adamou; Sanjeev Khanna; Insup Lee; Insik Shin; Shiyu Zhou

2001-01-01

336

REAL-TIME ENVIRONMENTAL MONITORING: APPLICATIONS FOR HOMELAND SECURITY  

EPA Science Inventory

Real-time monitoring technology developed as part of the EMPACT program has a variety of potential applications. These tools can measure a variety of potential contaminants in the air, water, in buildings, or in the soil. Real-time monitoring technology allows these detection sys...

337

Associative processor applications to real-time data management  

Microsoft Academic Search

This paper describes a research study concerning the potential of associative processing as a solution to the problem of real-time data management. The desired outcome of the research was an evaluation of the comparative advantages of associative processing over conventional sequential processing as applied to general real-time Data Management System (DMS) problems. The specific DMS application framework within which the

Richard R. Linde; Roy Gates; Te-Fu Peng

1973-01-01

338

Soft Real-Time Scheduling on Performance Asymmetric Multicore Platforms  

Microsoft Academic Search

This paper discusses an approach for supporting soft real-time periodic tasks in Linux on performance asymmetric multicore platforms (AMPs). Such architectures consist of a large number of processing units on one or several chips, where each processing unit is capable of executing the same instruction set at a different performance level. We discuss deficiencies of Linux in supporting periodic real-time

John M. Calandrino; Dan P. Baumberger; Tong Li; Scott Hahn; James H. Anderson

2007-01-01

339

Comparison of Real-Time Optical Correlators for Pattern Recognition.  

National Technical Information Service (NTIS)

Two types of optical correlators have been built to investigate real-time pattern recognition. The first employs one-dimensional devices to perform the two dimensional correlation in real time. This architecture uses an array of light emitting diodes (LED...

K. T. Stalker, P. A. Molley, B. D. Hansche

1989-01-01

340

Algorithmic tools for real-time microsurgery simulation  

Microsoft Academic Search

Today, there is growing interest in computer surgical simulation to enhance surgeons’ training. This paper presents a simulation system based on novel algorithms for animating instruments interacting with deformable tissue in real-time. The focus is on computing the deformation of a tissue subject to external forces, and detecting collisions among deformable and rigid objects. To achieve real-time performance, the algorithms

Joel Brown; Stephen Sorkin; Jean-Claude Latombe; Kevin Montgomery; Michael Stephanides

2002-01-01

341

17 CFR 38.157 - Real-time market monitoring.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Real-time market monitoring. 38.157 Section 38.157...TRADING COMMISSION DESIGNATED CONTRACT MARKETS Compliance With Rules § 38.157 Real-time market monitoring. A designated contract...

2013-04-01

342

The Synchronous Approach to Reactive and Real-Time Systems  

Microsoft Academic Search

The state of the art in real-time programming is briefly reviewed. The synchronous approach is then introduced informally and its possible impact on the design of real-time and reactive systems is discussed. The authors present and discuss the application fields and the principles of synchronous programming. The major concern of the synchronous approach is to base synchronous programming languages on

A. Benveniste; G. Berry

1991-01-01

343

Real-time filesystems - Guaranteeing timing constraints for disk accesses in RT-Mach  

Microsoft Academic Search

Traditional real-time systems have largely avoided the use of disks due to their relative slow speeds and their un- predictability. However, many real-time applications in- cluding multimedia systems and real-time database ap- plications benefit significantly from the use of disks to store and access real-time data. In this paper, we investigate the problem of obtaining guaranteed timely access to files

Anastasio Molano; Kanaka Juvva; Ragunathan Rajkumar

1997-01-01

344

Information display and interaction in real-time environments  

NASA Technical Reports Server (NTRS)

The available information bandwidth as a funcion of system's complexity and time constraints in a real time control environment were examined. Modern interactive graphics techniques provide very high bandwidth data displays. In real time control environments, effective information interaction rates are a function not only of machine data technologies but of human information processing capabilities and the four dimensional resolution of available interaction techniques. The available information bandwidth as a function of system's complexity and time constraints in a real time control environment were examined.

Bocast, A. K.

1983-01-01

345

Biology's built-in Faraday cages  

NASA Astrophysics Data System (ADS)

Biological fluids are water-based, ionic conductors. As such, they have both high relative dielectric constants and substantial conductivities, meaning they are lossy dielectrics. These fluids contain charged molecules (free charges), whose movements play roles in essentially all cellular processes from metabolism to communication with other cells. Using the problem of a point source in air above a biological fluid of semi-infinite extent, the bound charges in the fluid are shown to perform the function of a fast-acting Faraday cage, which protects the interior of the fluid from external electric fields. Free charges replace bound charges in accordance with the fluid's relaxation time, thereby providing a smooth transition between the initial protection provided by the bound charges and the steady state protection provided by the free charges. The electric fields within the biological fluid are thus small for all times just as they would be inside a classical Faraday cage.

Klee, Maurice M.

2014-05-01

346

Recent advances to obtain real - Time displacements for engineering applications  

USGS Publications Warehouse

This paper presents recent developments and approaches (using GPS technology and real-time double-integration) to obtain displacements and, in turn, drift ratios, in real-time or near real-time to meet the needs of the engineering and user community in seismic monitoring and assessing the functionality and damage condition of structures. Drift ratios computed in near real-time allow technical assessment of the damage condition of a building. Relevant parameters, such as the type of connections and story structural characteristics (including geometry) are used in computing drifts corresponding to several pre-selected threshold stages of damage. Thus, drift ratios determined from real-time monitoring can be compared to pre-computed threshold drift ratios. The approaches described herein can be used for performance evaluation of structures and can be considered as building health-monitoring applications.

Celebi, M.

2005-01-01

347

Testing real-time modeling of a gas transmission pipeline  

SciTech Connect

Pipeline modeling in a real-time, on-line environment enables pipeline operators to better analyze and understand their pipeline. A real-time model provides accurate representation of current and future pipeline operation. To verify the continuous accuracy of the real-time and predictive models, calculated results are compared to SCADA measurements with extensive testing. LICconsult, Inc. (LIC) implemented an on-line real-time pipeline simulation software system (PSS) for Northern Border Pipeline Co. (NBPL). This article describes the extensive testing performed on the PSS as well as actual test cases identifying benefits realized through implementation of modeling. The main purpose of these tests was to verify that the real-time model accurately predicted the effects of a compressor station start-up or shut-down, thereby increasing the operator`s confidence in the model.

Tisdale, E. [Northern Border Pipeline Co., Houston, TX (United States); Maamari, M.J. [LICconsult, Inc., Houston, TX (United States)

1997-02-01

348

Recent achievements in real-time computational seismology in Taiwan  

NASA Astrophysics Data System (ADS)

Real-time computational seismology is currently possible to be achieved which needs highly connection between seismic database and high performance computing. We have developed a real-time moment tensor monitoring system (RMT) by using continuous BATS records and moment tensor inversion (CMT) technique. The real-time online earthquake simulation service is also ready to open for researchers and public earthquake science education (ROS). Combine RMT with ROS, the earthquake report based on computational seismology can provide within 5 minutes after an earthquake occurred (RMT obtains point source information < 120 sec; ROS completes a 3D simulation < 3 minutes). All of these computational results are posted on the internet in real-time now. For more information, welcome to visit real-time computational seismology earthquake report webpage (RCS).

Lee, S.; Liang, W.; Huang, B.

2012-12-01

349

Real-Time Processing in Client-Server Databases  

Microsoft Academic Search

In this paper, we propose and experimentally evaluate the use of the client-server database paradigm for real-time processing. To date, the study of transaction processing with time constraints has mostly been restricted to centralized or \\

Vinay Kanitkar; Alex Delis

2002-01-01

350

Real-Time Embedded High Performance Computing: Application Benchmarks.  

National Technical Information Service (NTIS)

The final report develops realistic benchmarks to assess the applicability of current memory massively parallel processors (MPPs) for real-time embedded applications, such as synthetic aperture radar (SAR) and space-time adaptive processing (STAP). A scal...

C. P. Brown M. I. Flanzbaum R. A. Games J. D. Ramsdell

1995-01-01

351

Overview of real-time computer systems technical analysis of the Modcomp implementation of a proprietary system MAX IV'' and real-time UNIX system REAL/IX''  

SciTech Connect

There many applications throughout industry and government requiring real-time computing. Any application that monitors and/or controls a process would fit into this category. Some examples are: Nuclear power plants, Steel mills, Space program, etc. General Atomics uses eight real-time computer systems for control and high speed data acquisition required to run the nuclear fusion experiments. Real-Time computing can be defined as the ability to respond to asynchronous external events in a predictable (preferably fast) time frame. Real-Time computer systems are similar to other computers in many ways and may by used for general computing requirements such as Time-Sharing. However special hardware, operating systems and software had to be developed to meet the requirement for real-time computing. Traditionally, real-time computing has been a realm of proprietary operating systems with real-time applications written in FORTRAN and assembly language. In the past, these systems adequately served the needs of the real-time world. Many of these systems that were developed 15 years ago are still being used today. However the real-time world is now changing, demanding new systems to be developed. This paper gives a description of general real-time computer systems and how they differ from other systems. However, the main purpose of this paper is to give a detailed technical description of the hardware and operating systems of an existing proprietary system and a real-time UNIX system. The two real-time computer systems described in detail are Modcomp Classic III/95 with the MAX IV operating system and Modcomp TRI-D 9750 with the REAL/IX.2 operating system.

Cummings, J.

1990-10-01

352

Model-checking for Probabilistic Real-time Systems  

Microsoft Academic Search

Model-checking is a method of verifying concurrent systems in which a state-graph modelof the system behavior is compared with a temporal logic formula. This paper extends modelcheckingto stochastic real-time systems, whose behavior depends on probabilistic choice andquantitative time. The specification language is TCTL, a branching-time temporal logic forexpressing real-time properties. We interpret the formulas of the logic over generalized semiMarkovprocesses.

Rajeev Alur; Costas Courcoubetis; David L. Dill

1991-01-01

353

New Scheme of Implementing Real-Time Linux  

Microsoft Academic Search

To well support the real-time requirement from applications, we enhance the real-time ability in Linux kernel through two new kernel mechanisms. Firstly, we present a new microsecond-level timer mechanism based on UTIME provided by Kurt-Linux, but different from it. The new timing implementation provides more flexible mechanism to support the different-grained timing requirement, as well as more flexible and preferential

Xue-Yu Hong; Ling Zhang; Jin-Long Hu

2006-01-01

354

Reviewing real-time performance of nuclear reactor safety systems  

SciTech Connect

The purpose of this paper is to recommend regulatory guidance for reviewers examining real-time performance of computer-based safety systems used in nuclear power plants. Three areas of guidance are covered in this report. The first area covers how to determine if, when, and what prototypes should be required of developers to make a convincing demonstration that specific problems have been solved or that performance goals have been met. The second area has recommendations for timing analyses that will prove that the real-time system will meet its safety-imposed deadlines. The third area has description of means for assessing expected or actual real-time performance before, during, and after development is completed. To ensure that the delivered real-time software product meets performance goals, the paper recommends certain types of code-execution and communications scheduling. Technical background is provided in the appendix on methods of timing analysis, scheduling real-time computations, prototyping, real-time software development approaches, modeling and measurement, and real-time operating systems.

Preckshot, G.G. [Lawrence Livermore National Lab., CA (United States)

1993-08-01

355

Faraday imaging at high temperatures  

DOEpatents

A Faraday filter rejects background light from self-luminous thermal objects, but transmits laser light at the passband wavelength, thus providing an ultra-narrow optical bandpass filter. The filter preserves images so a camera looking through a Faraday filter at a hot target illuminated by a laser will not see the thermal radiation but will see the laser radiation. Faraday filters are useful for monitoring or inspecting the uranium separator chamber in an atomic vapor laser isotope separation process. Other uses include viewing welds, furnaces, plasma jets, combustion chambers, and other high temperature objects. These filters are can be produced at many discrete wavelengths. A Faraday filter consists of a pair of crossed polarizers on either side of a heated vapor cell mounted inside a solenoid.

Hackel, Lloyd A. (Livermore, CA); Reichert, Patrick (Hayward, CA)

1997-01-01

356

Faraday imaging at high temperatures  

DOEpatents

A Faraday filter rejects background light from self-luminous thermal objects, but transmits laser light at the passband wavelength, thus providing an ultra-narrow optical bandpass filter. The filter preserves images so a camera looking through a Faraday filter at a hot target illuminated by a laser will not see the thermal radiation but will see the laser radiation. Faraday filters are useful for monitoring or inspecting the uranium separator chamber in an atomic vapor laser isotope separation process. Other uses include viewing welds, furnaces, plasma jets, combustion chambers, and other high temperature objects. These filters are can be produced at many discrete wavelengths. A Faraday filter consists of a pair of crossed polarizers on either side of a heated vapor cell mounted inside a solenoid. 3 figs.

Hackel, L.A.; Reichert, P.

1997-03-18

357

Expert systems for real-time monitoring and fault diagnosis  

NASA Technical Reports Server (NTRS)

Methods for building real-time onboard expert systems were investigated, and the use of expert systems technology was demonstrated in improving the performance of current real-time onboard monitoring and fault diagnosis applications. The potential applications of the proposed research include an expert system environment allowing the integration of expert systems into conventional time-critical application solutions, a grammar for describing the discrete event behavior of monitoring and fault diagnosis systems, and their applications to new real-time hardware fault diagnosis and monitoring systems for aircraft.

Edwards, S. J.; Caglayan, A. K.

1989-01-01

358

Real-Time Scheduling with a Budget  

Microsoft Academic Search

Suppose that we are given a set of jobs, where each job has a processing time, a non-negative weight, and a set of possible time intervals in which it can be processed. In addition, each job has a processing cost. Our goal is to schedule a feasible subset of the jobs on a single machine, such that the total weight

Joseph Naor; Hadas Shachnai; Tami Tamir

2003-01-01

359

Elapsed Time in the Real World  

NSDL National Science Digital Library

This 3-lesson unit develops students' abilities to measure and model elapsed time in various ways. Students construct clocks, time line models, and they read and interpret schedules. The lessons employ hands on activities, interactive technology, and literature to enhance understanding. Student materials, assessments and solutions are provided.

Maple, John; Straub, Kristie

2007-01-01

360

Real time resource allocation in distributed systems  

Microsoft Academic Search

In this paper we consider a resource allocation problem which is local in the sense that the maximum number of users competing for a particular resource at any time instant is bounded and also at any time instant the maximum number of resources that a user is willing to get is bounded. The problem may be viewed as that of

John H. Reif; Paul G. Spirakis

1982-01-01

361

Real-Time Functional Magnetic Resonance Imaging  

Microsoft Academic Search

A recursive algorithm suitable for functional magnetic reso- nance imaging (FMRI) calculations is presented. The correla- tion coefficient of a time course of images with a reference time series, with the mean and any linear trend projected out, may be computed with 22 operations per voxel, per image; the storage overhead is four numbers per voxel. A statistical model for

Robert W. Cox; Andrzej Jesmanowicz; James S. Hyde

1995-01-01

362

Faraday rotation measurements at Ootacamund  

NASA Technical Reports Server (NTRS)

The results of Faraday rotation measurements made at Ootacamund during ATS-6 phase II are presented. For summer and equinoctial months, even though no clear noon bite-out is observed in the variation of Faraday a decrease is observed in the rate of increase of rotation around 0900-1000 hours LT. This is attributed to the 'fountain effect' which is responsible for the noontime bite-out in F2-region peak electron density.

Sethia, G.; Chandra, H.; Deshpande, M. R.; Rastogi, R. G.

1978-01-01

363

Toward real-time performance benchmarks for Ada  

NASA Technical Reports Server (NTRS)

Benchmarks are developed to measure the Ada notion of time, the Ada features believed important to real-time performance, and other time-related features that are not part of the language, but are part of the run-time system; these benchmarks are then applied to the language and run-time system, and the results evaluated.

Clapp, Russell M.; Duchesneau, Louis; Volz, Richard A.; Mudge, Trevor N.; Schultze, Timothy

1986-01-01

364

Time domain and frequency domain conditions for strict positive realness  

NASA Technical Reports Server (NTRS)

The author states various time-domain and frequency-domain conditions pertaining to multivariate strict positive real systems and establishes the relationship between these conditions. Their relationship is clarified by means of a three-tier diagram; each tier represents a set of equivalent conditions successively stronger than the lower tier. The main theorem in the present study can be considered as the positive realness lemma for strictly positive real systems.

Wen, John T.

1988-01-01

365

Giant terahertz Faraday rotation in graphene  

NASA Astrophysics Data System (ADS)

The Faraday rotation of the polarization of light in a medium, where the time-reversal symmetry is broken due to external magnetic field, is an optical analogue of the Hall effect. We recently demonstrated that graphene, the thinnest existing material, can turn the polarization of terahertz radiation by several degrees in modest magnetic fields, which is a spectacular manifestation of the cyclotron resonance. In this talk I will review our Faraday rotation spectroscopy studies of single-layer and twisted multilayer epitaxial graphene with an emphasis on the physical information that one can extract from these measurements and potential applications.[4pt] [1] I. Crassee et al. Nature Physics 7, 48 (2011).[0pt] [2] I. Crassee et al. Phys. Rev. B, 84, 035103 (2011).

Kuzmenko, Alexey

2012-02-01

366

Heterodyne-enhanced Faraday rotation spectrometer  

NASA Astrophysics Data System (ADS)

A novel heterodyne-enhanced Faraday rotation spectroscopic (H-FRS) system for trace gas detection of nitric oxide (NO) is demonstrated. The system is based on a quantum cascade laser emitting at ~5.2 ?m and a mercury cadmium telluride photodetector (both thermoelectrically cooled). The heterodyne detection is performed at 30MHz, where the laser relative intensity noise is significantly smaller than at low frequencies. With an implementation of active interferometer stabilization technique, the current system shows total noise level that is only 5.4 times above the fundamental shot-noise limit and the Faraday rotation angle sensitivity of 2.6 × 10-8 rad/?Hz. The NO detection limit of 30.7 ppb-v/?Hz was achieved for the R(8.5)e NO transition using 100 Gauss magnetic field and 0.15 m optical path length.

Wang, Yin; Nikodem, Michal; Hoyne, Jake; Wysocki, Gerard

2012-01-01

367

Real-Time Scheduling with a Budget  

Microsoft Academic Search

Suppose that we are given a set of jobs, where each job has a processing time, a non-negative weight, and a set of possible\\u000a time intervals in which it can be processed. In addition, each job has a processing cost. Our goal is to schedule a feasible\\u000a subset of the jobs on a single machine, such that the total weight

Hadas Shachnai; Tami Tamir

2007-01-01

368

Space Shuttle Main Engine real time stability analysis  

NASA Astrophysics Data System (ADS)

The Space Shuttle Main Engine (SSME) is a reusable, high performance, liquid rocket engine with variable thrust. The engine control system continuously monitors the engine parameters and issues propellant valve control signals in accordance with the thrust and mixture ratio commands. A real time engine simulation lab was installed at MSFC to verify flight software and to perform engine dynamic analysis. A real time engine model was developed on the AD100 computer system. This model provides sufficient fidelity on the dynamics of major engine components and yet simplified enough to be executed in real time. The hardware-in-the-loop type simulation and analysis becomes necessary as NASA is continuously improving the SSME technology, some with significant changes in the dynamics of the engine. The many issues of interfaces between new components and the engine can be better understood and be resolved prior to the firing of the engine. In this paper, the SSME real time simulation Lab at the MSFC, the SSME real time model, SSME engine and control system stability analysis, both in real time and non-real time is presented.

Kuo, F. Y.

1993-06-01

369

Real-time compressive sensing spectral domain optical coherence tomography  

PubMed Central

We developed and demonstrated real-time compressive sensing (CS) spectral domain optical coherence tomography (SD OCT) B-mode imaging at excess of 70 fps. The system was implemented using a conventional desktop computer architecture having three graphics processing units (GPUs). This result shows speed gain of 459 and 112 times compared to best CS implementations based on the MATLAB and C++ respectively and that real-time CS-SDOCT imaging can finally be realized.

Xu, Daguang; Huang, Yong; Kang, Jin U.

2014-01-01

370

A composable, energy-managed, real-time MPSOC platform  

Microsoft Academic Search

Multi-processors systems on chip (MPSOC) platforms emerged in embedded systems as hardware solutions to support the continuously increasing functionality and performance demands in this domain. Such a platform has to execute a mix of applications with diverse performance and timing constraints, i.e., real-time or non-real-time, thus different application schedulers should co-exist on an MPSOC. Moreover, applications share many MPSOC resources,

Anca Molnos; Jude Angelo Ambrose; Andrew Nelson; Radu Stefan; Sorin Cotofana; Kees Goossens

2010-01-01

371

Real-Time Camera Control for Interactive Storytelling  

Microsoft Academic Search

In this paper, we present a fully implemented prototype of real-time cinematic control for character-based interactive storytelling approaches, where story diversity emerges from dynamic interaction between characters. We describe the specifities of real-time cinematic control within a dynamic virtual environment, where events occur at different locations at the same time. We also present results based on a situation of interaction

Fred Charles; Jean-luc Lugrin; Marc Cavazza; Steven J. Mead

2002-01-01

372

Distributed real time database systems: background and literature review  

Microsoft Academic Search

Today’s real-time systems (RTS) are characterized by managing large volumes of dispersed data making real-time distributed\\u000a data processing a reality. Large business houses need to do distributed processing for many reasons, and they often must do\\u000a it in order to stay competitive. So, efficient database management algorithms and protocols for accessing and manipulating\\u000a data are required to satisfy timing constraints

Udai Shanker; Manoj Misra; Anil Kumar Sarje

2008-01-01

373

Research of real-time Traffic Emergency Evacuation management  

Microsoft Academic Search

A scientific and effective emergency evacuation plan plays an important part in improving the event reaction ability of the urban traffic system, as well as, saves rescue time and reduces property losses. A new approach for real-time Traffic Emergency Evacuation management is proposed in this paper. Distinct from the well-studied evacuation planning, real-time traffic management for evacuation aims at dynamically

Yue-ming Chen; Hui Geng

2010-01-01

374

Real time statistical process control for plasma etching  

Microsoft Academic Search

The development and the application of a real-time statistical process control (SPC) scheme are presented. Based on time-series and multivariate statistics, this scheme can accommodate real-time sensor readings such as can be collected from a single-wafer plasma etcher via the SECSII communications protocol. The scheme has been successfully applied on a Lam Rainbow plasma etcher, and it has been able

Hai-Fang Guo; Costas J. Spanos; Alan J. Miller

1991-01-01

375

Dynamic Scheduling of Real-Time Tasks under Precedence Constraints  

Microsoft Academic Search

While scheduling theory has been developed over a long period of time, it is important to note that most results concern problems with static characteristics. However, a real-time system is dynamic and requires on-line and adaptive scheduling strategies. So, an important aspect of real-time systems research is to devise methods flexible enough to react to a dynamic change of processor

Houssine Chetto; Maryline Silly; T. Bouchentouf

1990-01-01

376

Real-time Intrusion Detection and Suppression in ATM Networks  

Microsoft Academic Search

Distributed mission critical systems require support for ultra-secure communication, in which intrusions must be detected and suppressed in real time, possibly before the affected messages reach the receiver. When the dis- tributed application has real-time requirements, the ef- fects of intrusion are particularly severe. In addition to coveredchannelsand potentiallytampereddata at the re- ceiver,suchsystemsmayexperienceviolationsoftiming requirements and timing instabilities in components not

Riccardo Bettati; Wei Zhao; D. Teodor

1999-01-01

377

Real-Time Measurements of Jet Aircraft Engine Exhaust  

Microsoft Academic Search

Particulate-phase exhaust properties from two different types of ground-based jet aircraft engines—high-thrust and turboshaft—were studied with real-time instruments on a portable pallet and additional time-integrated sampling devices. The real-time instruments successfully characterized rapidly changing particulate mass, light absorption, and polycyclic aromatic hydrocarbon (PAH) content. The integrated measurements included particulate-size distributions, PAH, and carbon concentrations for an entire test run (i.e.,

Fred Rogers; Pat Arnott; Barbara Zielinska; John Sagebiel; Kerry E. Kelly; David Wagner; JoAnn S. Lighty; Adel F. Sarofim

2005-01-01

378

Concurrent Algorithms for Real-Time Memory Management  

Microsoft Academic Search

The conflict between the performance demands of real-time systems and the shared-resource needs of high-level languages (Ada in particular) is examined. Shared memory requires carefully designed concurrency control, but the traditional approach, which is to embed the entire allocate-release implementation code in critical sections, is unsuitable for real-time applications because it results in excessively high response time. The design and

Ray Ford

1988-01-01

379

Power Minimisation for Real-Time Dataflow Applications  

Microsoft Academic Search

Energy efficient execution of applications is im- portant for many reasons, e.g. time between battery charges, device temperature. Voltage and Frequency Scaling (VFS) en- ables applications to be run at lower frequencies on hardware resources thereby consuming less power. Real-time applications have deadlines that must be met otherwise their output is devalued. Dataflow modelling of real-time applications enables off-line verification

Andrew Nelson; Orlando Moreira; Anca Molnos; Sander Stuijk; Ba Thang Nguyen; Kees Goossens

2011-01-01

380

Real-Time, Subwavelength Terahertz Imaging  

NASA Astrophysics Data System (ADS)

The fields of biosensing, nanospectroscopy, and plasmonics have great potential for near-field terahertz (THz) technology. In this work, we demonstrate that electro-optic (EO) imaging combined with the brightness of recently developed intense THz sources permits the imaging of subwavelength-size samples without compromising spatial resolution or acquisition time. We report on recent advances in this field and current achievements in optimizing spatial resolution and acquisition time. Near-field imaging demonstrations on field enhancement in metallic-based resonators and metamaterials are also discussed. This development will accelerate our comprehension of subwavelength light-matter interactions at THz frequencies and enable new spectroscopic applications.

Blanchard, F.; Doi, A.; Tanaka, T.; Tanaka, K.

2013-07-01

381

Real-time dynamic simulation of the Cassini spacecraft using DARTS. Part 2: Parallel/vectorized real-time implementation  

NASA Technical Reports Server (NTRS)

Part 1 of this paper presented the requirements for the real-time simulation of Cassini spacecraft along with some discussion of the DARTS algorithm. Here, in Part 2 we discuss the development and implementation of parallel/vectorized DARTS algorithm and architecture for real-time simulation. Development of the fast algorithms and architecture for real-time hardware-in-the-loop simulation of spacecraft dynamics is motivated by the fact that it represents a hard real-time problem, in the sense that the correctness of the simulation depends on both the numerical accuracy and the exact timing of the computation. For a given model fidelity, the computation should be computed within a predefined time period. Further reduction in computation time allows increasing the fidelity of the model (i.e., inclusion of more flexible modes) and the integration routine.

Fijany, A.; Roberts, J. A.; Jain, A.; Man, G. K.

1993-01-01

382

New bounded real lemma for discrete-time singular systems  

Microsoft Academic Search

In this paper, the problem of bounded real lemma for discrete-time singular system with strict matrix inequalities is investigated. It is proved that the bounded real lemma for discrete singular system can be described by a strict matrix inequality. The results lead to more tractable and reliable computation when applying them to design control systems.

Gaomin Zhang; Yuanqing Xia; Peng Shi

2008-01-01

383

Trajectory planning for optimal robot catching in real-time  

Microsoft Academic Search

Many real-world tasks require fast planning of highly dynamic movements for their execution in real- time. The success often hinges on quickly finding one of the few plans that can achieve the task at all. A further challenge is to quickly find a plan which optimizes a desired cost. In this paper, we will discuss this problem in the context

Roberto Lampariello; Duy Nguyen-Tuong; Claudio Castellini; Gerd Hirzinger; Jan Peters

2011-01-01

384

The case for feedback control real-time scheduling  

Microsoft Academic Search

Despite the significant body of results in real-time scheduling, many real world problems are not easily supported. While algorithms such as Earliest Deadline First, Rate Monotonic, and the Spring scheduling algorithm can support sophisticated task set characteristics (such as deadlines, precedence constraints, shared resources, jitter, etc.), they are all \\

Jack A. Stankovic; Chenyang Lu; Sang Hyuk Son; Gang Tao

1999-01-01

385

Real-time FPGA-based architecture for stereo vision  

NASA Astrophysics Data System (ADS)

In this paper, an FPGA based architecture for stereo vision is discussed. The architecture provides a high-density disparity map in real time. The architecture is based on area comparison between the image pair using the sum of absolute differences. The architecture scans the input images in partial columns which are then processed in parallel. The system performs monolithically on a pair images in real time. The purpose of the system is to be integrated ins smart camera for real-time image analysis based on FPGA processing.

Arias-Estrada, Miguel; Xicotencatl, Juan M.

2001-04-01

386

Real Time Pattern Matching using Projection Kernels  

Microsoft Academic Search

A novel approach to pattern matching is presented in which time complexity is reduced by two orders of magnitude compared to traditional approaches. The suggested approach uses an efficient projection scheme which bounds the distance between a pattern and an image window using very few operations on average. The projection framework is combined with a rejection scheme which allows rapid

Yacov Hel-Or; Hagit Hel-Or

2005-01-01

387

Real-time mission and trajectory planning  

Microsoft Academic Search

An automated mission and trajectory planner for piloted as well as autonomous vehicle applications is described. The planning system is composed of a trajectory planner and a mission planner. The trajectory planner generates multiple, near-optimal trajectories between mission objectives and estimates the costs (in terms of time, energy and lethality) to fly those trajectories. The mission planner uses this information

Robert M. Beaton; Milton B. Adams; James V. A. Harrison

1987-01-01

388

Real time analysis of PETN detonation products  

Microsoft Academic Search

The freely expanding gases from the detonation of pentaerythritol tetranitrate (PETN) pellet were analyzed as rapidly as the molecules arrived at the mass spectrometer detector. It was found that all of the products arriving at the detector earliest, irrespective of mass, had the same velocity, 11 km s⁻¹ and peaked at 5 km s⁻¹. The width of the time distributions

N. C. Blais; J. J. Valentini

1985-01-01

389

75 FR 42399 - Orders Finding That the PJM WH Real Time Peak Daily Contract, PJM WH Real Time Off-Peak Daily...  

Federal Register 2010, 2011, 2012, 2013

...COMMISSION Orders Finding That the PJM WH Real Time Peak Daily Contract, PJM WH Real Time Off-Peak Daily Contract and PJM WH Day Ahead...determination whether the PJM \\2\\ WH \\3\\ Real Time Peak Daily [[Page 42400

2010-07-21

390

Real time chemical dynamics at surfaces  

NASA Astrophysics Data System (ADS)

It is a major goal in surface science to make movies of molecules on surfaces, in which the reaction of the molecules on the surface can be followed on a femtosecond time scale, with sub-nanometer resolution. By moving the actors (the molecules) to precisely determined positions on the stage (the surface) at some well-defined moment in time, and subsequently making a space- and time-resolved documentary of what happens next, we would be able to understand the reactive interactions between molecules on surfaces in the greatest possible detail. This would enable us to set the stage and bring together the actors in such a way as to produce the chemical outcomes our society needs, by improving existing catalysts and designing novel catalysts, and by engineering novel reactions on surfaces. Any future director of such movies needs to know which techniques (i.e., which theoretical and experimental methods) hold promise for movie making, what has been done with these techniques, and what can be done with appropriate extensions. The methods we discuss are: (i) the time-dependent wave packet method, which is a theoretical method for simulating molecule-surface reactions with sub-nanometer resolution on a femtosecond time scale, (ii) molecular beam experiments, which allow detailed investigation of the molecule-surface interaction at a molecular level, and (iii) time-resolved laser pump-probe experiments, which allow reactions to be studied with femtosecond resolution. In particular, we discuss (i) theoretical studies of the dissociation reaction of hydrogen on metal surfaces, the reactive system presently understood at the greatest level of detail, (ii) the reactive and non-reactive scattering of heavy diatomics (NO,CO) from metal surfaces, and (iii) the competition between reaction of coadsorbed CO with O and desorption of CO, again on a metal surface. We examine possibilities to extend these methods to make movies at the desired level of detail. We also discuss which reactions are likely to provide good material for plots of movies that will be exciting for future generations of surface scientists.

Bonn, M.; Kleyn, A. W.; Kroes, G. J.

2002-03-01

391

Near real-time and real-time GNSS Precise Point Positioning with external a priori troposphere models  

NASA Astrophysics Data System (ADS)

Precise Point Positioning (PPP) is a positioning technique that uses a single GNSS (Global Navigation Satellite System) receiver that requires external information from analysis of global GNSS permanent network, in particular precise orbits and satellite clocks. This technique is commonly used in post-processing mode and gives results comparable to relative positioning. A shortcoming of this technique is the time required for the solution to converge, which is a main limitation for near real-time and real-time applications. The convergence time depends on the quality of GNSS data, on the accuracy of the a priori parameters and on fast ambiguity resolution. Until recently, near real-time and real-time users were limited in the sources of precise products, since only the predicted part of the ultra-rapid products were available. In 2012, the International GNSS Service (IGS) launched the Real-Time Service (RTS), making available a dedicated set of real-time products, known as IGS-RTS. Nevertheless, there is still no standard procedure for handling the troposphere delay. The a priori troposphere delay, as well as mapping functions, has to be derived from an external source and the adjustment model should account for the correction to an apriori value of the delay. Currently, a number of empirical troposphere state models and mapping functions are available for users in real-time. Near-real time model of troposphere delay can also be determined from the analysis of regional GNSS permanent network. In this paper, we make use of the IGS-RTS along with a number of a priori tropospheric models in order the assess how they influence convergence time and estimated position. For this purpose, we use GPS Analysis and Positioning Software (GAPS) for near-real time processing and GNSS-Wroclaw Algorithms for Real-time Positioning (GNSS-WARP) software for real-time processing of GPS only data together with IGS-RTS precise orbits and satellite clocks. As a priori troposphere model we used GPT together with the Saastamoinen formula, UNB3 model and regional near-real time troposphere model from the analysis of a network of permanent GNSS stations. We combine these models with Niell and VMF mapping functions to compute slant troposphere delays, including those of low-elevation satellites.

Hadas, Tomasz; Santos, Marcelo; Garcia, Alex; Bosy, Jaroslaw; Kaplon, Jan

2014-05-01

392

Real-time adaptive aircraft scheduling  

NASA Technical Reports Server (NTRS)

One of the most important functions of any air traffic management system is the assignment of ground-holding times to flights, i.e., the determination of whether and by how much the take-off of a particular aircraft headed for a congested part of the air traffic control (ATC) system should be postponed in order to reduce the likelihood and extent of airborne delays. An analysis is presented for the fundamental case in which flights from many destinations must be scheduled for arrival at a single congested airport; the formulation is also useful in scheduling the landing of airborne flights within the extended terminal area. A set of approaches is described for addressing a deterministic and a probabilistic version of this problem. For the deterministic case, where airport capacities are known and fixed, several models were developed with associated low-order polynomial-time algorithms. For general delay cost functions, these algorithms find an optimal solution. Under a particular natural assumption regarding the delay cost function, an extremely fast (O(n ln n)) algorithm was developed. For the probabilistic case, using an estimated probability distribution of airport capacities, a model was developed with an associated low-order polynomial-time heuristic algorithm with useful properties.

Kolitz, Stephan E.; Terrab, Mostafa

1990-01-01

393

Building flexible real-time systems using the Flex language  

NASA Technical Reports Server (NTRS)

The design and implementation of a real-time programming language called Flex, which is a derivative of C++, are presented. It is shown how different types of timing requirements might be expressed and enforced in Flex, how they might be fulfilled in a flexible way using different program models, and how the programming environment can help in making binding and scheduling decisions. The timing constraint primitives in Flex are easy to use yet powerful enough to define both independent and relative timing constraints. Program models like imprecise computation and performance polymorphism can carry out flexible real-time programs. In addition, programmers can use a performance measurement tool that produces statistically correct timing models to predict the expected execution time of a program and to help make binding decisions. A real-time programming environment is also presented.

Kenny, Kevin B.; Lin, Kwei-Jay

1991-01-01

394

Giant Faraday rotation induced by the Berry phase in bilayer graphene under strong terahertz fields  

NASA Astrophysics Data System (ADS)

High-order terahertz (THz) sideband generation in semiconductors is a phenomenon with physics similar to that of high-order harmonic generation but in a regime of much lower frequency. Our previous paper [1] found that the electron–hole pair excited by a weak optical laser can accumulate a Berry phase along a cyclic trajectory under the driving of a strong elliptically polarized THz field. Furthermore, the Berry phase appears as the Faraday rotation angle of the emission signal under short-pulse excitation in monolayer MoS_{2}. In this paper, the theory of the Berry phase in THz extreme nonlinear optics is applied to biased bilayer graphene with Bernal stacking, which has similar Bloch band features and optical properties to monolayer MoS_{2}, such as the time-reversal related valleys and the valley contrasting optical selection rule. However, the biased bilayer graphene has much larger Berry curvature than monolayer MoS_{2}, which leads to a large Berry phase of the quantum trajectory and in turn a giant Faraday rotation of the optical emission (?1 rad for a THz field with frequency 1 THz and strength 8 kV cm?1). This surprisingly big angle shows that the Faraday rotation can be induced more efficiently by the Berry curvature in momentum space than by the magnetic field in real space. It provides opportunities to use bilayer graphene and THz lasers for ultrafast electro-optical devices.

Yang, Fan; Xu, Xiaodong; Liu, Ren-Bao

2014-04-01

395

Midplane Faraday Rotation: A densitometer for BPX  

SciTech Connect

The density in a high field, high density tokamak such as BPX can be determined by measuring the Faraday rotation of a 10.6 {mu}m laser directed tangent to the toroidal field. If there is a horizontal array of such beams, then n{sub e}(R) can be readily obtained with a simple Abel version about the center line of the tokamak. For BPX operated at full field and density, the rotation angle would be quite large -- about 75{degrees} per pass. A layout in which a single laser beam is fanned out in the horizontal midplane of the tokamak, with a set of retroreflectors on the far side of the vacuum vessel, would provide good spatial resolution, depending only upon the number of reflectors. With this proposed layout, only one window would be needed. Because the rotation angle is never more than 1 ``fringe,`` the data is always good, and it is also a continuous measurement in time. Faraday rotation is dependent only upon the plasma itself, and thus is not sensitive to vibration of the optical components. Simulations of the expected results show that BPX would be well served even at low densities by a Midplane Faraday Rotation densitometer of {approximately}64 channels. Both TFTR and PBX-M would be suitable test beds for the BPX system.

Jobes, F.C.; Mansfield, D.K.

1992-02-01

396

Midplane Faraday Rotation: A densitometer for BPX  

SciTech Connect

The density in a high field, high density tokamak such as BPX can be determined by measuring the Faraday rotation of a 10.6 {mu}m laser directed tangent to the toroidal field. If there is a horizontal array of such beams, then n{sub e}(R) can be readily obtained with a simple Abel version about the center line of the tokamak. For BPX operated at full field and density, the rotation angle would be quite large -- about 75{degrees} per pass. A layout in which a single laser beam is fanned out in the horizontal midplane of the tokamak, with a set of retroreflectors on the far side of the vacuum vessel, would provide good spatial resolution, depending only upon the number of reflectors. With this proposed layout, only one window would be needed. Because the rotation angle is never more than 1 fringe,'' the data is always good, and it is also a continuous measurement in time. Faraday rotation is dependent only upon the plasma itself, and thus is not sensitive to vibration of the optical components. Simulations of the expected results show that BPX would be well served even at low densities by a Midplane Faraday Rotation densitometer of {approximately}64 channels. Both TFTR and PBX-M would be suitable test beds for the BPX system.

Jobes, F.C.; Mansfield, D.K.

1992-02-01

397

Developing infrared array controller with software real time operating system  

NASA Astrophysics Data System (ADS)

Real-time capabilities are required for a controller of a large format array to reduce a dead-time attributed by readout and data transfer. The real-time processing has been achieved by dedicated processors including DSP, CPLD, and FPGA devices. However, the dedicated processors have problems with memory resources, inflexibility, and high cost. Meanwhile, a recent PC has sufficient resources of CPUs and memories to control the infrared array and to process a large amount of frame data in real-time. In this study, we have developed an infrared array controller with a software real-time operating system (RTOS) instead of the dedicated processors. A Linux PC equipped with a RTAI extension and a dual-core CPU is used as a main computer, and one of the CPU cores is allocated to the real-time processing. A digital I/O board with DMA functions is used for an I/O interface. The signal-processing cores are integrated in the OS kernel as a real-time driver module, which is composed of two virtual devices of the clock processor and the frame processor tasks. The array controller with the RTOS realizes complicated operations easily, flexibly, and at a low cost.

Sako, Shigeyuki; Miyata, Takashi; Nakamura, Tomohiko; Motohara, Kentaro; Uchimoto, Yuka Katsuno; Onaka, Takashi; Kataza, Hirokazu

2008-08-01

398

Practice Drawing Contours: Using Real-Time Data  

NSDL National Science Digital Library

This applet provides practice in contour drawing using real-time data plots. There are six colors for drawing isolines and a button for erasing the last line. There is also a link to other contour analysis exercises.

Whittaker, Tom; Ackerman, Steve

399

Architecture of Triad: A Distributed, Real-Time, Trusted System.  

National Technical Information Service (NTIS)

The Triad project is a prototype trusted operating system development. The name Triad represents the trio of requirements which this system must satisfy: multilevel security, real time processing, and distributed processing. The goal of this project is to...

E. J. Sebes N. Kelem M. Bernstein J. Jones E. Cohen

1995-01-01

400

Real-Time Trajectory Generation for Autonomous Nonlinear Flight Systems.  

National Technical Information Service (NTIS)

Unmanned aerial vehicle and smart munition systems need robust, real- time path generation and guidance systems to avoid terrain obstructions, navigate in hazardous weather conditions, and react to mobile threats such as radar, jammers, and unfriendly air...

M. Larsen R. W. Beard T. W. McLain

2006-01-01

401

A switchable peptide sensor for real-time lysosomal tracking.  

PubMed

A bis-spiropyran functionalized peptide 1, which exhibits good cell-permeability, excellent biocompatibility and low cytotoxicity, has been developed for reversible and real-time lysosomal tracking. PMID:24714849

Chen, Lei; Wu, Junchen; Schmuck, Carsten; Tian, He

2014-06-21

402

Transrectal real-time elastography of the prostate: Normal patterns  

Microsoft Academic Search

IntroductionGiven the growing importance in clinical practice of transrectal real-time sonoelastography of the prostate, it is important to define normal patterns correlated to volume growth and reconsider the technical problems.

A. Goddi; A. Sacchi; G. Magistretti; J. Almolla

403

Module Interconnection Frameworks for a Real-Time Spreadsheet.  

National Technical Information Service (NTIS)

Phase I research into a modular real-time spreadsheet has yielded a significant result: A spreadsheet can be used to completely simulate, completely prototype and completely implement distributed control systems. A usable implementation of such a system w...

R. Clarke

1993-01-01

404

A multiprocessing architecture for real-time monitoring  

NASA Technical Reports Server (NTRS)

A multiprocessing architecture for performing real time monitoring and analysis using knowledge-based problem solving techniques is discussed. To handle asynchronous inputs and perform in real time, the system consists of three or more separate processes which run concurrently on one or more processors and communicate via a message passing scheme. The Data Management Process gathers, compresses, scales and sends the incoming telemetry data to other tasks. The Inference Process consists of a proprietary high performance inference engine that runs at 1000 rules per second using telemetry data to perform real time analysis on the state and health of the Space Telescope. The multiprocessing architecture has been interfaced to a simulator and is able to process the incoming telemetry in real time.

Laffey, Thomas J.; Schmidt, James L.; Read, Jackson Y.; Kao, Simon M.

1987-01-01

405

Development of Real-Time Monitors for Gaseous Formaldehyde.  

National Technical Information Service (NTIS)

Two new methods for real-time measurement of gaseous formaldehyde have been developed. One is a spectroscopic method based on direct fluorescence detection of gaseous formaldehyde following excitation with UV light. This method has been developed to the p...

T. J. Kelly R. H. Barnes

1990-01-01

406

Real-time PCR detection of male-specific coliphages.  

PubMed

Male-specific coliphages are often used as indicators of contamination by enteric viruses. These phages can be detected in water samples by plaque assays and by polymerase chain reaction. In this study, the M13 coliphage was used to develop a real-time PCR assay for the detection of male-specific DNA coliphages. The real-time PCR was found to have a reaction efficiency of 1.45 and detection limit of 10(-3) plaque forming units per reaction mix. Repeated amplification and melting curve analyses demonstrated high specificity and reproducibility of the real-time assay. Quantitative detection with the real-time PCR should allow rapid assessment of the level of viral contamination in water. PMID:18376795

Yong, S F Y; Ngeow, Y F; Tong, Y K; Ong, J T

2006-12-01

407

Real-time chirp diagnostic for ultrashort laser pulses.  

PubMed

Using a real-time Fourier-transform algorithm, we present a simple technique for measuring the chirp of femtosecond laser pulses. We demonstrate significantly enhanced sensitivity compared with standard autocorrelation measurements. PMID:18007952

Hirayama, Toshiyuki; Sheik-Bahae, Mansoor

2002-05-15

408

Real-Time Implementation of Nonlinear Optical Processing Functions.  

National Technical Information Service (NTIS)

Optical data processing has not yet achieved its potential of increased capacity and speed compared with conventional electronic techniques, primarily for lack of a practical real-time image modulator, and because optical techniques have been almost exclu...

B. H. Soffer

1983-01-01

409

Real-Time Implementation of Nonlinear Optical Processing Functions.  

National Technical Information Service (NTIS)

Optical data processing has not yet achieved its potential of increased capacity and speed compared with conventional electronic techniques, primarily for lack of a practical real-time image modulator, and because optical techniques have been almost exclu...

B. H. Soffer

1982-01-01

410

Hard-real-time resource management for autonomous spacecraft  

NASA Technical Reports Server (NTRS)

This paper describes tickets, a computational mechanism for hard-real-time autonomous resource management. Autonomous spacecraftcontrol can be considered abstractly as a computational process whose outputs are spacecraft commands.

Gat, E.

2000-01-01

411

Intelligent data management for real-time spacecraft monitoring  

NASA Technical Reports Server (NTRS)

Real-time AI systems have begun to address the challenge of restructuring problem solving to meet real-time constraints by making key trade-offs that pursue less than optimal strategies with minimal impact on system goals. Several approaches for adapting to dynamic changes in system operating conditions are known. However, simultaneously adapting system decision criteria in a principled way has been difficult. Towards this end, a general technique for dynamically making such trade-offs using a combination of decision theory and domain knowledge has been developed. Multi-attribute utility theory (MAUT), a decision theoretic approach for making one-time decisions is discussed and dynamic trade-off evaluation is described as a knowledge-based extension of MAUT that is suitable for highly dynamic real-time environments, and provides an example of dynamic trade-off evaluation applied to a specific data management trade-off in a real-world spacecraft monitoring application.

Schwuttke, Ursula M.; Gasser, Les; Abramson, Bruce

1992-01-01

412

Cluster Computing for Embedded/Real-Time Systems  

NASA Technical Reports Server (NTRS)

Embedded and real-time systems, like other computing systems, seek to maximize computing power for a given price, and thus can significantly benefit from the advancing capabilities of cluster computing.

Katz, D.; Kepner, J.

1999-01-01

413

Real-time earthquake monitoring: Early warning and rapid response  

NASA Technical Reports Server (NTRS)

A panel was established to investigate the subject of real-time earthquake monitoring (RTEM) and suggest recommendations on the feasibility of using a real-time earthquake warning system to mitigate earthquake damage in regions of the United States. The findings of the investigation and the related recommendations are described in this report. A brief review of existing real-time seismic systems is presented with particular emphasis given to the current California seismic networks. Specific applications of a real-time monitoring system are discussed along with issues related to system deployment and technical feasibility. In addition, several non-technical considerations are addressed including cost-benefit analysis, public perceptions, safety, and liability.

1991-01-01

414

Above Real-Time Training Applied to Air Combat Skills.  

National Technical Information Service (NTIS)

Above real-time training (ARTT) is an instructional strategy in which events in a training simulator occur faster than normal. Three experiments were conducted to evaluate applications of ARTT for training air combat skills and emergency procedures. Two o...

P. M. Crane D. Guckenberger B. T. Schreiber R. L. Robbins

1997-01-01

415

Real-Time Online Communications: 'Chat' Use in Navy Operations.  

National Technical Information Service (NTIS)

The ability to conduct a real-time conversation online has become a ubiquitous component of today's communications environment. Commonly referred to as chat or instant messaging, this mode of communication provides users with a format that facilitates mul...

N. J. Heacox R. A. Moore J. G. Morrison R. F. Yturralde

2004-01-01

416

Challenges of AVHRR Vegetation Data for Real Time Applications  

NASA Technical Reports Server (NTRS)

Remote sensing data has long been used to monitor global ecosystems for floods and droughts and AVHRR data, as one of the first product, has many users interested in receiving the data within hours of acquisition. With the introduction of a new series of sensors in 2000 (the AVHRR/3 series), the quality of the NDVI datasets available for real time environmental monitoring has declined. This paper provides evidence of problems of cloud contamination, calibration and noise in the real time data which are not present in the historical AVHRR NDVIg dataset. These differences introduce significant uncertainty in the use of the real time data, degrading their utility for detecting climate variations in near real time.

Brown, Molly

2008-01-01

417

Near Real Time Rectification and Gridding of Apt Satellite Pictures.  

National Technical Information Service (NTIS)

A technique is described in which an ordinary APT satellite picture is recieved and at least three geographic features identified. The satellite signal is digitized in real time by the Raytheon 440 computer. The picture coordinates and earth coordinates o...

J. T. Young

1971-01-01

418

Generating Real-Time Clutter Sequences - Preliminary Fortran Version.  

National Technical Information Service (NTIS)

Attached is a Fortran subroutine (TIMESQ) and a companion subroutine (GAUSSPN) to generate essentially a continuous clutter signal sequence where the parameters are set in real-time. For this preliminary version, three arrays, specifying the amplitude spe...

R. L. Mitchell

1978-01-01

419

Cybersecurity through Real-Time Distributed Control Systems.  

National Technical Information Service (NTIS)

Critical infrastructure sites and facilities are becoming increasingly dependent on interconnected physical and cyber-based real-time distributed control systems (RTDCSs). A mounting cybersecurity threat results from the nature of these ubiquitous and som...

J. J. Nutaro J. K. Munro L. P. MacIntyre R. A. Kisner W. W. Manges

2010-01-01

420

Methods for Intelligent Real-Time Simulation of Multibody Dynamics.  

National Technical Information Service (NTIS)

This document contains the Final Technical of the research project entitled Method for Intelligent Real Time Simulation of Multibody Dynamics. The report includes a statement of the problems studied, the scientific accomplishments, most important results,...

E. Bayo

1998-01-01

421

Catheter ablation guided by real-time MRI.  

PubMed

Real-time magnetic resonance imaging (MRI) combines the advantages of excellent soft-tissue characterization in a true 3D anatomical and functional model with the possibility of lesion and gap visualization without the need of any radiation. Therefore, real-time MRI presents a particularly attractive imaging technology to guide electrophysiology studies and catheter ablation procedures. This article aims to provide an overview on current routine clinical application of MRI in the setting of interventional electrophysiology. Furthermore, development of real-time MRI guided electrophysiology studies and first experiences with MRI guided catheter ablation procedures are depicted. In this context advantages, challenges and limitations of real-time MRI guided catheter ablation as well as future perspectives are discussed. PMID:24952899

Eitel, Charlotte; Hindricks, Gerhard; Grothoff, Matthias; Gutberlet, Matthias; Sommer, Philipp

2014-08-01

422

Real time analysis of PETN detonation products  

SciTech Connect

The freely expanding gases from the detonation of pentaerythritol tetranitrate (PETN) pellet were analyzed as rapidly as the molecules arrived at the mass spectrometer detector. It was found that all of the products arriving at the detector earliest, irrespective of mass, had the same velocity, 11 km s/sup -1/ and peaked at 5 km s/sup -1/. The width of the time distributions varied from one species to another. Mass and velocity spectra of the important products were obtained and the most intense signals were found to be H/sub 2/O, CO, and CO/sub 2/, but H/sub 2/O was by far the largest. Smaller signals arising from O, HCN, HCO, and NO/sub 2/ were also found. Comparisons of the spectrum with other experiments are discussed. 8 refs. 5 figs.

Blais, N.C.; Valentini, J.J.

1985-01-01

423

Real-time airborne particle analyzer  

SciTech Connect

An aerosol particle analyzer includes a laser ablation chamber, a gas-filled conduit, and a mass spectrometer. The laser ablation chamber can be operated at a low pressure, which can be from 0.1 mTorr to 30 mTorr. The ablated ions are transferred into a gas-filled conduit. The gas-filled conduit reduces the electrical charge and the speed of ablated ions as they collide and mix with buffer gases in the gas-filled conduit. Preferably, the gas filled-conduit includes an electromagnetic multipole structure that collimates the nascent ions into a beam, which is guided into the mass spectrometer. Because the gas-filled conduit allows storage of vast quantities of the ions from the ablated particles, the ions from a single ablated particle can be analyzed multiple times and by a variety of techniques to supply statistically meaningful analysis of composition and isotope ratios.

Reilly, Peter T.A.

2012-10-16

424

A knowledge based real-time travel time prediction system for urban network  

Microsoft Academic Search

Many approaches had been proposed for travel time prediction in these decades; most of them focus on the predicting the travel time on freeway or simple arterial network. Travel time prediction for urban network in real time is hard to achieve for several reasons: complexity and path routing problem in urban network, unavailability of real-time sensor data, spatiotemporal data coverage

Wei-hsun Lee; Shian-shyong Tseng; Sheng-han Tsai

2009-01-01

425

Real-time 3D image-guided HIFU therapy  

Microsoft Academic Search

Real-time three-dimensional ultrasound imaging (4D US) was utilized to monitor the treatment site during high-intensity focused ultrasound (HIFU) treatment. To obtain real-time monitoring during HIFU sonication, a 4D US imaging system and HIFU were synchronized and interference on the US image adjusted so that the region of interest was visible during treatment. The system was tested using tissue mimicking phantom

Ali Ziadloo; Shahram Vaezy

2008-01-01

426

Real-Time Person Identification System for Intelligent Digital TV  

Microsoft Academic Search

Intelligent digital TV (iDTV) is an enhanced digital TV that can automatically provide user-personalized services for each audience. For the user-personalized services, the iDTV should recognize audiences in real-time. Thus, in this paper, we define a novel structure of the iDTV and propose a real-time person identification system embedded in the iDTV. The proposed system consists of three phases: preprocessing

Min-Cheol Hwang; Le Thanh Ha; Seung-Kyun Kim; Sung-Jea Ko

2007-01-01

427

A Decision Theoretic Framework for Real-Time Communication  

Microsoft Academic Search

We consider a communication system in which the outputs of a Markov source are encoded and decoded in real-time by a finite memory receiver, and the dis- tortion measure does not tolerate delays. The objective is to choose designs, i.e. real-time encoding, decoding and memory update strategies that minimize a total expected distortion measure. This is a dynamic team problem

Aditya Mahajan; Demosthenis Teneketzis

2005-01-01

428

The Design and Performance of Real-Time Java Middleware  

Microsoft Academic Search

Over 90 percent of all microprocessors are now used for real-time and embedded applications. Since the behav- ior of these applications is often constrained by the physi- cal world, it is important to devise higher-level languages and middleware that meet conventional functional require- ments and dependably and productively enforce real-time constraints. This paper provides two contributions to the study of

Angelo Corsaro; Douglas C. Schmidt

2003-01-01

429

Constructing Abstract Models of Concurrent Real-Time Software  

Microsoft Academic Search

Concurrent real-time software is used in many safety-critical applications. Assuring the quality of such software requires the use of formal methods. Before a program can be analyzed formally, however, we must construct a mathematical model that captures the aspects of the program we want to verify. In this paper, we show how to construct mathematical models of concurrent real-time software

James C. Corbett

1996-01-01

430

Towards a complete real-time electricity market design  

Microsoft Academic Search

The general design for the real-time electricity market presented in this paper optimizes and prices both real and reactive\\u000a power simultaneously in an AC setting, where all assets—generation, load and transmission—are allowed to bid and are financially\\u000a settled at the locational price times energy consumed or produced. The result is that transmission lines are compensated for\\u000a both capacity and admittance,

Richard P. O’Neill; Emily Bartholomew Fisher; Benjamin F. Hobbs; Ross Baldick

2008-01-01

431

FDDI protocols optimized for real time and packet data transmission  

Microsoft Academic Search

The high performance protocol of the fiber data distributed interface-hybrid ring control (FDDI-HRC) is discussed to show its strengths and weakness with regard to the task of concurrently meeting the needs of real-time and packet data applications. The random allocation and de-allocation of isochronous bandwidth (the bandwidth allocated to real-time applications) in an FDDI-HRC system could cause the packet data

S. Lance Van Noslrand; Alexander Albicki

1990-01-01

432

Real time trinocular stereo for tele-immersion  

Microsoft Academic Search

Tele-immersion is a technology that augments your space with real-time 3D projections of remote spaces thus facili- tating the interaction of people from different places in vir- tually the same environment. Tele-immersion combines 3D scene recovery from computer vision, and rendering and interaction from computer graphics. We describe the real- time 3D scene acquisition using a new algorithm for trinoc-

Jane Mulligan; Kostas Daniilidis

2001-01-01

433

A real-time traffic sign recognition system  

Microsoft Academic Search

The ability of recognising traffic signs in a road traffic scenario is an important feature of the Daimler-Benz autonomous vehicle VITA II. This real-time vision-based traffic sign recognition system has been developed by Daimler-Benz in the European research project PROMETHEUS. In this paper we focus on the overall system design, the real-time implementation, and field test evaluation. The software architecture

S. Estable; J. Schick; F. Stein; R. Janssen; R. Ott; W. Ritter; Y.-J. Zheng

1994-01-01

434

Distributed Advance Reservation of Real-Time Connections  

Microsoft Academic Search

The ability to reserve real-time connections in advance is essential in all distributedmulti-party applications (i.e., applications involving multiple human beings)using a network that controls admissions to provide good quality of service. Thispaper discusses the requirements of the clients of an advance reservation service, anda distributed design for such a service. The design is described within the context ofthe Tenet Real-Time

Domenico Ferrari; Amit Gupta; Giorgio Ventre

1995-01-01

435

Learning to Act Using Real-Time Dynamic Programming  

Microsoft Academic Search

Learning methods based on dynamic programming (DP) are receiving increasing attentionin artificial intelligence. Researchers have argued that DP provides the appropriatebasis for compiling planning results into reactive strategies for real-time control,as well as for learning such strategies when the system being controlled is incompletelyknown. We introduce an algorithm based on DP, which we call Real-Time DP(RTDP), by which an embedded

Andrew G. Barto; Steven J. Bradtke; Satinder P. Singh

1995-01-01

436

Detailed Real-Time Urban 3D Reconstruction from Video  

Microsoft Academic Search

The paper presents a system for automatic, geo-registered, real-time 3D recon- struction from video of urban scenes. The system collects video streams, as well as GPS and inertia measurements in order to place the reconstructed models in geo-registered coordinates. It is designed using current state of the art real-time modules for all processing steps. It employs commodity graphics hardware and

Marc Pollefeys; David Nistér; Jan-michael Frahm; Amir Akbarzadeh; Philippos Mordohai; Brian Clipp; Christoph Engels; David Gallup; Seon Joo Kim; Paul Merrell; C. Salmi; Sudipta N. Sinha; B. Talton; Liang Wang; Qingxiong Yang; Henrik Stewénius; Ruigang Yang; Greg Welch; Herman Towles

2008-01-01

437

Real-time transputer-based measurement apparatus: performance testing  

Microsoft Academic Search

The paper deals with transputer-based equipment used in on-line indirect measurement on induction motors, by using an estimation algorithm, performed in real time. Starting with a brief description of the actual equipment, some considerations relating to the multiprocessor architecture are reported, in order to point out hardware and software solutions adopted to fit real-time requirements. The dynamic behavior of the

Giovanni Bucci; Antonietta Germano; Carmine Landi

1994-01-01

438

Hashtables for Embedded and Real-Time Systems  

Microsoft Academic Search

Data abstractions such as hash tables are included in most runtime libraries because of their widespread use and straightforward implementation. While operating systems and programming languages continue to improve their real-time features, much of what is offered by a runtime library is not yet suitable for real-time or embedded-systems. In this paper, we present an algorithm for managing hash tables

Scott Friedman; Nicholas Leidenfrost; Benjamin C. Brodie; Ron K. Cytron

439

Real-time radiography at the NECTAR facility  

NASA Astrophysics Data System (ADS)

A feasibility study has shown that real-time radiography using fission neutrons is possible at the NECTAR facility, when using an improved detection system for fast variations (Bücherl et al., 2009 [1]). Continuing this study, real-time measurements of slowly varying processes like the water uptake in medium sized trunks (diameter about 12 cm) and of slow periodic processes (e.g. a slowly rotating iron disk) are investigated successfully using the existing detection system.

Bücherl, T.; Lierse von Gostomski, Ch.

2011-09-01

440

Species identification in meat products using real-time PCR  

Microsoft Academic Search

One of the most convenient methods for the identification of animal species in processed meat products is the examination of DNA sequences. Real-time polymerase chain reaction (qPCR) techniques are particularly suitable because even small fragments of DNA formed during heat processing of the meat can be amplified and identified. A real-time PCR method has been developed and evaluated for the

K. M. Jonker; J. J. H. C. Tilburg; G. H. Hägele; E. de Boer

2008-01-01

441

Experimental Evaluation of Real-Time Optimistic Concurrency Control Schemes  

Microsoft Academic Search

Due to its potential for a high degree of parallelism, optimistic concurrency control is expected to perform better than two-phase locking when integrated with priority-driven CPU scheduling in real-time database sys- tems. In this paper, we examine the overall effects and the impact of the overheads in- volved in implementing real-time optimistic concurrency control. Using a locking mecha- nism to

Jiandong Huang; John A. Stankovic; Krithi Ramamritham; Donald F. Towsley

1991-01-01

442

Real-time simulation of heat transfer in continuous casting  

Microsoft Academic Search

A real-time heat-transfer model for continuous slab casting is presented. The model calculates the strand temperatures and\\u000a the solid shell thickness profile along the machine as a function of the actual casting variables, strand geometry, and steel\\u000a grade. The special requirements con-cerning the real-time use of the model and, in general, the accuracy of the model are\\u000a also studied and

Seppo Louhenkilpi; Erkki Laitinen; Risto Nieminen

1993-01-01

443

Statically Safe Speculative Execution for Real-Time Systems  

Microsoft Academic Search

Deterministic worst-case execution for satisfying hard-real-time constraints, and speculative execution with rollback for improving average-case throughput, appear to lie on opposite ends of a spectrum of performance requirements and strategies. Nonetheless, we show that there are situations in which speculative execution can improve the performance of a hard real-time system, either by enhancing average performance while not affecting the worst-case,

Mohamed F. Younis; Thomas J. Marlowe; Alexander D. Stoyen; Grace Tsai

1999-01-01

444

Real time hardware-in-the-loop vehicle simulation  

Microsoft Academic Search

The models used to simulate an engine, driveline, vehicle, and tire\\/road-surface models are described. Several control units was linked together to provide a generic real-time hardware-in-the-loop (HITL) simulation is described. The HITL simulation structure and models were designed generically so that they can be utilized for developing a variety of control systems. Generic real-time HITL simulation can use analytical and

Sheran Alles; Curtis Swick; Syed Mahmud; Feng Lin

1992-01-01

445

Real-Time Classification of Electromyographic Signals for Robotic Control  

Microsoft Academic Search

Advances in bioengineering have led to increasingly so- phisticated prosthetic devices for amputees and para- lyzed individuals. Control of such devices necessitates real-time classification of biosignals, e.g., electromyo- graphic (EMG) signals recorded from intact muscles. In this paper, we show that a 4-degrees-of-freedom robotic arm can be controlled in real-time using non-invasive surface EMG signals recorded from the forearm. The

Beau Crawford; Kai Miller; Pradeep Shenoy; Rajesh P. N. Rao

2005-01-01

446

From Motion Capture to Real-Time Character Animation  

Microsoft Academic Search

This paper describes a framework for animating virtual characters in real-time environments thanks to motion capture data.\\u000a In this paper, we mainly focus on the adaptation of motion capture data to the virtual skeleton and to its environment. To\\u000a speed-up this real-time process we introduce a morphology-independent representation of motion. Based on this representation,\\u000a we have redesigned the methods for

Franck Multon; Richard Kulpa; Ludovic Hoyet; Taku Komura

2008-01-01

447

Adaptive Real-Time Systems and the FPAA  

Microsoft Academic Search

\\u000a Adaptive real-time systems are often typically considered by design engineers to be a solely digital preserve. However, in\\u000a recent years analogue technologies such as the Field programmable Analogue Array (FPAA) have been developed to support real-time\\u000a reconfiguration. These technologies can offer an analogue platform for a vast number of applications requiring adaptive processing\\u000a and form the subject of this paper.

Stuart Colsell; Reuben Edwards

2003-01-01

448

Real-time solar wind forecasting: Capabilities and challenges  

Microsoft Academic Search

A user-friendly, real-time, observation-driven system for forecasting solar wind and interplanetary magnetic field conditions is described. The forecast system presently uses the Hakamada–Akasofu–Fry (version 2) kinematic solar wind model to predict, in real-time, solar wind conditions in the heliosphere, including at the location of Mars, and beyond. Properly characterizing and predicting this region of the space environment are essential steps

C. D. Fry; T. R. Detman; M. Dryer; Z. Smith; W. Sun; C. S. Deehr; S.-I. Akasofu; C.-C. Wu; S. McKenna-Lawlor

2007-01-01

449

Applying Optimization Principle Patterns to Design Real-Time ORBs  

Microsoft Academic Search

First-generation CORBA middleware was reasonably success- ful at meeting the demands of request\\/response applications with best-effort quality of service (QoS) requirements. Sup- porting applications with more stringent QoS requirements poses new challenges for next-generation real-time CORBA middleware, however. This paper provides three contributions to the design and optimization of real-time CORBA middle- ware. First, we outline the challenges faced by

Irfan Pyarali; Carlos O'ryan; Douglas C. Schmidt; Nanbor Wang; Vishal Kachroo; Aniruddha S. Gokhale

1999-01-01

450

RISA: A Real-Time Interactive Shadow Avatar  

Microsoft Academic Search

As Webcams become an important factor in the PC environment, many camera-based communication techniques have been developed. Among them, gesture-based communication is attracting attention. In this paper, we propose a real-time interactive shadow avatar (RISA) which can express facial emotions by changing as response to the user's gestures. The avatar's shape is a virtual shadow constructed from a real-time sampled

Yangmi Lim; Jinsu Kim; Jinseok Chae

2007-01-01

451

Constructing abstract models of concurrent real-time software  

Microsoft Academic Search

Concurrent real-time software is used in many safety-critical applications. Assuring the quality of such software requires the use of formal methods. Before a program can be analyzed formally, however, we must construct a mathematical model that captures the aspects of the program we want to verify. In this paper, we show how to construct mathematical models of concurrent real-time software

James C. Corbett

1996-01-01

452

In Vivo Real-Time, Multicolor, Quantum Dot Lymphatic Imaging  

Microsoft Academic Search

The lymphatic network is complex and difficult to visualize in real-time in vivo. Moreover, the direction of flow within lymphatic networks is often unpredictable especially in areas with well-developed “watershed” or overlapping lymphatics. Herein, we report a method of in vivo real-time multicolor lymphatic imaging using cadmium–selenium quantum dots (Qdots) with a fluorescence imaging system that enables the simultaneous visualization

Nobuyuki Kosaka; Mikako Ogawa; Noriko Sato; Peter L Choyke; Hisataka Kobayashi

2009-01-01

453

Near real-time skin deformation mapping  

NASA Astrophysics Data System (ADS)

A novel in vivo approach is described that provides large area mapping of the mechanical properties of the skin in human patients. Such information is important in the understanding of skin health, cosmetic surgery[1], aging, and impacts of sun exposure. Currently, several methods have been developed to estimate the local biomechanical properties of the skin, including the use of a physical biopsy of local areas of the skin (in vitro methods) [2, 3, and 4], and also the use of non-invasive methods (in vivo) [5, 6, and 7]. All such methods examine localized areas of the skin. Our approach examines the local elastic properties via the generation of field displacement maps of the skin created using time-sequence imaging [9] with 2D digital imaging correlation (DIC) [10]. In this approach, large areas of the skin are reviewed rapidly, and skin displacement maps are generated showing the contour maps of skin deformation. These maps are then used to precisely register skin images for purposes of diagnostic comparison. This paper reports on our mapping and registration approach, and demonstrates its ability to accurately measure the skin deformation through a described nulling interpolation process. The result of local translational DIC alignment is compared using this interpolation process. The effectiveness of the approach is reported in terms of residual RMS, image entropy measures, and differential segmented regional errors.

Kacenjar, Steve; Chen, Suzie; Jafri, Madiha; Wall, Brian; Pedersen, Richard; Bezozo, Richard

2013-02-01

454

Ballistic and diffusive dynamics in a two-dimensional ideal gas of macroscopic chaotic Faraday waves  

NASA Astrophysics Data System (ADS)

We have constructed a macroscopic driven system of chaotic Faraday waves whose statistical mechanics, we find, are surprisingly simple, mimicking those of a thermal gas. We use real-time tracking of a single floating probe, energy equipartition, and the Stokes-Einstein relation to define and measure a pseudotemperature and diffusion constant and then self-consistently determine a coefficient of viscous friction for a test particle in this pseudothermal gas. Because of its simplicity, this system can serve as a model for direct experimental investigation of nonequilibrium statistical mechanics, much as the ideal gas epitomizes equilibrium statistical mechanics.

Welch, Kyle J.; Hastings-Hauss, Isaac; Parthasarathy, Raghuveer; Corwin, Eric I.

2014-04-01

455

Ballistic and diffusive dynamics in a two-dimensional ideal gas of macroscopic chaotic Faraday waves.  

PubMed

We have constructed a macroscopic driven system of chaotic Faraday waves whose statistical mechanics, we find, are surprisingly simple, mimicking those of a thermal gas. We use real-time tracking of a single floating probe, energy equipartition, and the Stokes-Einstein relation to define and measure a pseudotemperature and diffusion constant and then self-consistently determine a coefficient of viscous friction for a test particle in this pseudothermal gas. Because of its simplicity, this system can serve as a model for direct experimental investigation of nonequilibrium statistical mechanics, much as the ideal gas epitomizes equilibrium statistical mechanics. PMID:24827228

Welch, Kyle J; Hastings-Hauss, Isaac; Parthasarathy, Raghuveer; Corwin, Eric I

2014-04-01

456

A Formal Model for Real-Time Parallel Computation  

SciTech Connect

The imposition of real-time constraints on a parallel computing environment--- specifically high-performance, cluster-computing systems--- introduces a variety of challenges with respect to the formal verification of the system's timing properties. In this paper, we briefly motivate the need for such a system, and we introduce an automaton-based method for performing such formal verification. We define the concept of a consistent parallel timing system: a hybrid system consisting of a set of timed automata (specifically, timed Buechi automata as well as a timed variant of standard finite automata), intended to model the timing properties of a well-behaved real-time parallel system. Finally, we give a brief case study to demonstrate the concepts in the paper: a parallel matrix multiplication kernel which operates within provable upper time bounds. We give the algorithm used, a corresponding consistent parallel timing system, and empirical results showing that the system operates under the specified timing constraints.

Hui, Peter SY; Chikkagoudar, Satish

2012-12-29

457

A Scheduling Algorithm for Replicated Real-Time Tasks  

NASA Technical Reports Server (NTRS)

We present an algorithm for scheduling real-time periodic tasks on a multiprocessor system under fault-tolerant requirement. Our approach incorporates both the redundancy and masking technique and the imprecise computation model. Since the tasks in hard real-time systems have stringent timing constraints, the redundancy and masking technique are more appropriate than the rollback techniques which usually require extra time for error recovery. The imprecise computation model provides flexible functionality by trading off the quality of the result produced by a task with the amount of processing time required to produce it. It therefore permits the performance of a real-time system to degrade gracefully. We evaluate the algorithm by stochastic analysis and Monte Carlo simulations. The results show that the algorithm is resilient under hardware failures.

Yu, Albert C.; Lin, Kwei-Jay

1991-01-01

458

Explaining How to Play Real-Time Strategy Games  

NASA Astrophysics Data System (ADS)

Real-time strategy games share many aspects with real situations in domains such as battle planning, air traffic control, and emergency response team management which makes them appealing test-beds for Artificial Intelligence (AI) and machine learning. End user annotations could help to provide supplemental information for learning algorithms, especially when training data is sparse. This paper presents a formative study to uncover how experienced users explain game play in real-time strategy games. We report the results of our analysis of explanations and discuss their characteristics that could support the design of systems for use by experienced real-time strategy game users in specifying or annotating strategy-oriented behavior.

Metoyer, Ronald; Stumpf, Simone; Neumann, Christoph; Dodge, Jonathan; Cao, Jill; Schnabel, Aaron

459

Real-Time Classification of Streaming Sensor Data  

Microsoft Academic Search

The last decade has seen a huge interest in classification of time series. Most of this work assumes that the data resides in main memory and is processed offline. However, recent advances in sensor technologies require resource-efficient algorithms that can be implemented directly on the sensors as real-time algorithms. We show how a recently introduced framework for time series classification,

Shashwati Kasetty; Candice Stafford; Gregory P. Walker; Xiaoyue Wang; Eamonn J. Keogh

2008-01-01

460

Case Study in Functional Real-Time Programming.  

National Technical Information Service (NTIS)

A case study in functional real time programming is presented. Some solutions to the lack of time expressibility in functional languages are discussed. It was realized that not only the lack of time expressibility, but also the lack of a notion of indepen...

D. H. Fijma R. T. Udink

1991-01-01

461

Resource-Centric Real-Time Kernel and Middleware Services.  

National Technical Information Service (NTIS)

This report provides an in depth look at the problem of OS resource management for real-time and multimedia systems where multiple activities with different timing constraints must be scheduled concurrently. Time on a particular resource is shared among i...

R. Rajkumar

2002-01-01

462

On being optimistic about real-time constraints  

Microsoft Academic Search

Performance studies of concurrency control algorithms for conventional database systems have shown that, under most operating circumstances, locking protocols outperform optimistic techniques. Real-time database systems have special characteristics - timing constraints are associated with transactions, performance criteria are based on satisfaction of these timing constraints, and scheduling algorithms are priority driven. In light of these special characteristics, results regarding the

Jayant R. Haritsa; Michael J. Carey; Miron Livny

1990-01-01

463

List processing in real time on a serial computer  

Microsoft Academic Search

A real-time list processing system is one in which the time required by the elementary list operations (e.g. CONS, CAR, CDR, RPLACA, RPLACD, EQ, and ATOM in LISP) is bounded by a (small) constant. Classical implementations of list processing systems lack this property because allocating a list cell from the heap may cause a garbage collection, which process requires time

Henry G. Baker Jr.; R. L. Rivest

1978-01-01

464

Benefits of Real-Time Travel Information in Houston, Texas.  

National Technical Information Service (NTIS)

The report describes some of the possible benefits and uses of real-time travel time information in major cities in Texas. The report details the development of a system that used probe vehicles to directly measure travel times between key locations in th...

K. N. Balke G. L. Ullman W. R. McCasland C. E. Mountain C. L. Dudek

1995-01-01

465

Real-Time Data Use for Operational Space Weather Products  

NASA Astrophysics Data System (ADS)

The Space Vehicles Directorate of the Air Force Research Laboratory (AFRL/RVBX) and the Space Environment Division of the Space and Missile Systems Center (AFSPC SYAG/WMLE) have combined efforts to design, develop, test, implement, and validate numerical and graphical products for Air Force Space Command’s (AFSPC) Space Environmental Effects Fusion System (SEEFS). These products were developed to analyze, specify, and forecast the effects of the near-earth space environment on Department of Defense weapons, navigation, communications, and surveillance systems in real/near-real time. This real-time attribute is the primary factor in allowing for actual operational product output, but it’s also responsible for a variety of detrimental effects that need to be considered, researched, mitigated, or otherwise eliminated in future/upgrade product applications. This presentation will provide brief overviews of the SEEFS products, along with information and recommendations concerned with their near/real-time data acquisition and use, to include: input data requirements, inputs/outputs ownership, observation cadence, transmission/receipt links and cadence, data latency, quality control, error propagation and associated confidence level applications, and ensemble model run potentials. Validation issues related to real-time data will also be addressed, along with recommendations for new real-time data archiving that should prove operationally beneficial.

Quigley, S.; Nobis, T. E.

2010-12-01

466

A Formally Verified Application-Level Framework for Real-Time Scheduling on POSIX Real-Time Operating Systems  

Microsoft Academic Search

This paper presents a framework, called meta scheduler, for implementing real-time scheduling algorithms. The meta scheduler is a portable middleware layer component designed for implementations over POSIX-compliant operating systems. It accommodates pluggable real-time scheduling algorithms while offering the flexibility of platform independence —the singular underlying OS requirement is the now nearly ubiquitous POSIX compliance. The versatility of pluggable schedulers positions

Peng Li; Binoy Ravindran; Syed Suhaib; Shahrooz Feizabadi

2004-01-01

467

Designing a fuzzy scheduler for hard real-time systems  

NASA Technical Reports Server (NTRS)

In hard real-time systems, tasks have to be performed not only correctly, but also in a timely fashion. If timing constraints are not met, there might be severe consequences. Task scheduling is the most important problem in designing a hard real-time system, because the scheduling algorithm ensures that tasks meet their deadlines. However, the inherent nature of uncertainty in dynamic hard real-time systems increases the problems inherent in scheduling. In an effort to alleviate these problems, we have developed a fuzzy scheduler to facilitate searching for a feasible schedule. A set of fuzzy rules are proposed to guide the search. The situation we are trying to address is the performance of the system when no feasible solution can be found, and therefore, certain tasks will not be executed. We wish to limit the number of important tasks that are not scheduled.

Yen, John; Lee, Jonathan; Pfluger, Nathan; Natarajan, Swami

1992-01-01

468

Real-time measurement system of laser power in VC++  

NASA Astrophysics Data System (ADS)

ADLINK PCI-9114 multifunction data acquisition card, signal amplifier and multiplexer board and power sensor are used to establish the real-time measurement system of relative laser power. During producing laser, measuring and showing thermoelectric and photoelectric signal, calculating parameter and drawing the curve of relative power. Parameters of laser output power and energy are concerned with researchers. These parameters are important for evaluating laser system. In this paper, a real time laser power measure system is established. While laser system is operating, real time laser power measure system measured the power and energy of laser and plotted the waveform of relative laser power. The parameters such as pulse width, rise time, fall time, power integration, average power, peak power and average energy are computed.

Zhuo, Hong-Yan; Song, Ying-Song; Wang, Lei

2009-07-01

469

Faraday Loop in Changing Field  

NSDL National Science Digital Library

The EJS Faraday Loop Changing Field Model shows the induced emf in a changing external magnetic field. You can control the frequency, magnitude and type of variation in the external field as you would in the laboratory when using a function generator to produce current in a large coil. You can also change the size and orientation of the conducting loop. If Ejs is installed, right-clicking within the plot and selecting âOpen Ejs Modelâ from the pop-up menu item allows for editing of the model. The Faraday Loop Changing Field model was created using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_em_FaradayLoopChangingField.jar file will run the program if Java is installed. Ejs is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models.

Cox, Anne

2011-12-07

470

Improving abstraction, encapsulation, and performance within mixed-mode real-time Java applications  

Microsoft Academic Search

Much of the appeal of Java for the implementation of real-time software components derives from the ability to leverage the combination of non-real-time, soft real-time, and hard real-time components all written in the same Java language. To date, deployment of non-real-time Java far exceeds deployment of real-time Java. To improve the appeal of real-time Java, it is important to improve

Kelvin Nilsen

2007-01-01

471

Lightweight distributed computing for intraoperative real-time image guidance  

NASA Astrophysics Data System (ADS)

In order to provide real-time intraoperative guidance, computer assisted surgery (CAS) systems often rely on computationally expensive algorithms. The real-time constraint is especially challenging if several components such as intraoperative image processing, soft tissue registration or context aware visualization are combined in a single system. In this paper, we present a lightweight approach to distribute the workload over several workstations based on the OpenIGTLink protocol. We use XML-based message passing for remote procedure calls and native types for transferring data such as images, meshes or point coordinates. Two different, but typical scenarios are considered in order to evaluate the performance of the new system. First, we analyze a real-time soft tissue registration algorithm based on a finite element (FE) model. Here, we use the proposed approach to distribute the computational workload between a primary workstation that handles sensor data processing and visualization and a dedicated workstation that runs the real-time FE algorithm. We show that the additional overhead that is introduced by the technique is small compared to the total execution time. Furthermore, the approach is used to speed up a context aware augmented reality based navigation system for dental implant surgery. In this scenario, the additional delay for running the computationally expensive reasoning server on a separate workstation is less than a millisecond. The results show that the presented approach is a promising strategy to speed up real-time CAS systems.

Suwelack, Stefan; Katic, Darko; Wagner, Simon; Spengler, Patrick; Bodenstedt, Sebastian; Röhl, Sebastian; Dillmann, Rüdiger; Speidel, Stefanie

2012-02-01

472

Real-Time Tropospheric Delay Estimation using IGS Products  

NASA Astrophysics Data System (ADS)

The Federal Agency for Cartography and Geodesy (BKG) routinely provides zenith tropospheric delay (ZTD) parameter for the assimilation in numerical weather models since more than 10 years. Up to now the results flowing into the EUREF Permanent Network (EPN) or E-GVAP (EUMETNET EIG GNSS water vapour programme) analysis are based on batch processing of GPS+GLONASS observations in differential network mode. For the recently started COST Action ES1206 about "Advanced Global Navigation Satellite Systems tropospheric products for monitoring severe weather events and climate" (GNSS4SWEC), however, rapid updates in the analysis of the atmospheric state for nowcasting applications require changing the processing strategy towards real-time. In the RTCM SC104 (Radio Technical Commission for Maritime Services, Special Committee 104) a format combining the advantages of Precise Point Positioning (PPP) and Real-Time Kinematic (RTK) is under development. The so-called State Space Representation approach is defining corrections, which will be transferred in real-time to the user e.g. via NTRIP (Network Transport of RTCM via Internet Protocol). Meanwhile messages for precise orbits, satellite clocks and code biases compatible to the basic PPP mode using IGS products are defined. Consequently, the IGS Real-Time Service (RTS) was launched in 2013 in order to extend the well-known precise orbit and clock products by a real-time component. Further messages e.g. with respect to ionosphere or phase biases are foreseen. Depending on the level of refinement, so different accuracies up to the RTK level shall be reachable. In co-operation of BKG and the Technical University of Darmstadt the real-time software GEMon (GREF EUREF Monitoring) is under development. GEMon is able to process GPS and GLONASS observation and RTS product data streams in PPP mode. Furthermore, several state-of-the-art troposphere models, for example based on numerical weather prediction data, are implemented. Hence, it opens the possibility to evaluate the potential of troposphere parameter determination in real-time and its effect to Precise Point Positioning. Starting with an offline investigation of the influence of different RTS products and a priori troposphere models the configuration delivering the best results is used for a real-time processing of the GREF (German Geodetic Reference) network over a suitable period of time. The evaluation of the derived ZTD parameters and station heights is done with respect to well proven GREF, EUREF, IGS, and E-GVAP analysis results. Keywords: GNSS, Zenith Tropospheric Delay, Real-time Precise Point Positioning

Stürze, Andrea; Liu, Sha; Söhne, Wolfgang

2014-05-01

473

Real-time attitude determination and gyro calibration  

NASA Technical Reports Server (NTRS)

We present results for two real-time filters prototyped for the Compton Gamma Ray Observatory (GRO), the Extreme Ultraviolet Explorer (EUVE), the Cosmic Background Explorer (COBE), and the next generation of Geostationary Operational Environmental Satellites (GOES). Both real and simulated data were used to solve for attitude and gyro biases. These filters promise advantages over single-frame and batch methods for missions like GOES, where startup and transfer-orbit operations require quick knowledge of attitude and gyro biases.

Challa, M.; Filla, O.; Sedlak, J.; Chu, D.

1993-01-01

474

Real-time ip network simulation at gigabit data rates  

Microsoft Academic Search

In many of the network research or development projects, as well as in teaching \\/ academia, network simulators today play an important role. Network simulation tools can be generally classified as those performing simulations off-line in form of batch-type tasks, and those operating in real-time, often with the ability to interact with the real network hardware and traffic. However, limited

M. Zee; Miljenko Mikuc

2003-01-01

475

Temporal proof methodologies for real-time systems  

Microsoft Academic Search

. We extend the specification language of temporallogic, the corresponding verification framework, andthe underlying computational model to deal with real-timeproperties of concurrent and reactive systems. A global,discrete, and asynchronous clock is incorporated into themodel by defining the abstract notion of a real-time transitionsystem as a conservative extension of traditional transitionsystems: qualitative fairness requirements are replaced(and superseded) by quantitative...

Thomas A. Henzinger; Zohar Manna; Amir Pnueli

1991-01-01

476

Real-Time Simulation of the X-33 Aerospace Engine  

NASA Technical Reports Server (NTRS)

This paper discusses the development and performance of the X-33 Aerospike Engine RealTime Model. This model was developed for the purposes of control law development, six degree-of-freedom trajectory analysis, vehicle system integration testing, and hardware-in-the loop controller verification. The Real-Time Model uses time-step marching solution of non-linear differential equations representing the physical processes involved in the operation of a liquid propellant rocket engine, albeit in a simplified form. These processes include heat transfer, fluid dynamics, combustion, and turbomachine performance. Two engine models are typically employed in order to accurately model maneuvering and the powerpack-out condition where the power section of one engine is used to supply propellants to both engines if one engine malfunctions. The X-33 Real-Time Model is compared to actual hot fire test data and is been found to be in good agreement.

Aguilar, Robert

1999-01-01

477

Modeling and Real-Time Simulation of UPFC  

NASA Astrophysics Data System (ADS)

We have developed a digital real time simulator of Power Electronics Controllers, so called FACTS (Flexible AC Transmission Systems) Controllers and/or Custom Power by using MATLABTM/SIMULINKTM and dSPACETM System. This paper describes the modeling and the calculation accuracy of a UPFC (Unified Power Flow Controller) model. Hence the developed simulator operates at a large time step, in order to improve simulation accuracy, a correction processing of the switching delay is implemented into the UPFC model. Calculation accuracy of the real time UPFC model is the same level as EMTDCTM results. We confirm stable operation of the developed UPFC model with connecting a commercial real time digital simulator (RTDSTM).

Kimura, Misao; Takahashi, Choei; Kishibe, Hideto; Miyazaki, Yasuyuki; Noro, Yasuhiro; Iio, Naotaka

478

Real-Time Holographic Image Correction Using Bacteriorhodopsin  

NASA Technical Reports Server (NTRS)

We present experimental results of one-way coherent imaging through a thin phase-aberrating medium using a holographic technique with bacteriorhodopsin as a real-time holographic material. Bacteriorhodopsin is well suited for the application when the aberration is time varying because of its real-time writing and erasing characteristics, sensitivity, and spatial resolution. We show results with final image resolution of greater than 20 line pairs/mm and high signal-to-noise ratio using a polarization-holography approach.

Downie, John D.

1994-01-01

479

High-fidelity real-time maritime scene rendering  

NASA Astrophysics Data System (ADS)

The ability to simulate authentic engagements using real-world hardware is an increasingly important tool. For rendering maritime environments, scene generators must be capable of rendering radiometrically accurate scenes with correct temporal and spatial characteristics. When the simulation is used as input to real-world hardware or human observers, the scene generator must operate in real-time. This paper introduces a novel, real-time scene generation capability for rendering radiometrically accurate scenes of backgrounds and targets in maritime environments. The new model is an optimized and parallelized version of the US Navy CRUISE_Missiles rendering engine. It was designed to accept environmental descriptions and engagement geometry data from external sources, render a scene, transform the radiometric scene using the electro-optical response functions of a sensor under test, and output the resulting signal to real-world hardware. This paper reviews components of the scene rendering algorithm, and details the modifications required to run this code in real-time. A description of the simulation architecture and interfaces to external hardware and models is presented. Performance assessments of the frame rate and radiometric accuracy of the new code are summarized. This work was completed in FY10 under Office of Secretary of Defense (OSD) Central Test and Evaluation Investment Program (CTEIP) funding and will undergo a validation process in FY11.

Shyu, Hawjye; Taczak, Thomas M.; Cox, Kevin; Gover, Robert; Maraviglia, Carlos; Cahill, Colin

2011-05-01

480

The improved broadband Real-Time Seismic Network in Romania  

NASA Astrophysics Data System (ADS)

Starting with 2002 the National Institute for Earth Physics (NIEP) has developed its real-time digital seismic network. This network consists of 96 seismic stations of which 48 broad band and short period stations and two seismic arrays are transmitted in real-time. The real time seismic stations are equipped with Quanterra Q330 and K2 digitizers, broadband seismometers (STS2, CMG40T, CMG 3ESP, CMG3T) and strong motions sensors Kinemetrics episensors (+/- 2g). SeedLink and AntelopeTM (installed on MARMOT) program packages are used for real-time (RT) data acquisition and exchange. The communication from digital seismic stations to the National Data Center in Bucharest is assured by 5 providers (GPRS, VPN, satellite communication, radio lease line and internet), which will assure the back-up communications lines. The processing centre runs BRTT's AntelopeTM 4.10 data acquisition and processing software on 2 workstations for real-time processing and post processing. The Antelope Real-Time System is also providing automatic event detection, arrival picking, event location and magnitude calculation. It provides graphical display and reporting within near-real-time after a local or regional event occurred. Also at the data center was implemented a system to collect macroseismic information using the internet on which macro seismic intensity maps are generated. In the near future at the data center will be install Seiscomp 3 data acquisition processing software on a workstation. The software will run in parallel with Antelope software as a back-up. The present network will be expanded in the near future. In the first half of 2009 NIEP will install 8 additional broad band stations in Romanian territory, which also will be transmitted to the data center in real time. The Romanian Seismic Network is permanently exchanging real -time waveform data with IRIS, ORFEUS and different European countries through internet. In Romania, magnitude and location of an earthquake are now available within a few minutes after the earthquake occurred. One of the greatest challenges in the near future is to provide shaking intensity maps and other ground motion parameters, within 5 minutes post-event, on the Internet and GIS-based format in order to improve emergency response, public information, preparedness and hazard mitigation

Neagoe, C.; Ionescu, C.

2009-04-01

481

A Practical Approach to Implementing Real-Time Semantics  

NASA Technical Reports Server (NTRS)

This paper investigates implementations of process algebras which are suitable for modeling concurrent real-time systems. It suggests an approach for efficiently implementing real-time semantics using dynamic priorities. For this purpose a proces algebra with dynamic priority is defined, whose semantics corresponds one-to-one to traditional real-time semantics. The advantage of the dynamic-priority approach is that it drastically reduces the state-space sizes of the systems in question while preserving all properties of their functional and real-time behavior. The utility of the technique is demonstrated by a case study which deals with the formal modeling and verification of the SCSI-2 bus-protocol. The case study is carried out in the Concurrency Workbench of North Carolina, an automated verification tool in which the process algebra with dynamic priority is implemented. It turns out that the state space of the bus-protocol model is about an order of magnitude smaller than the one resulting from real-time semantics. The accuracy of the model is proved by applying model checking for verifying several mandatory properties of the bus protocol.

Luettgen, Gerald; Bhat, Girish; Cleaveland, Rance

1999-01-01

482

A multiprocessing architecture for real-time monitoring  

NASA Technical Reports Server (NTRS)

A multitasking architecture for performing real-time monitoring and analysis using knowledge-based problem solving techniques is described. To handle asynchronous inputs and perform in real time, the system consists of three or more distributed processes which run concurrently and communicate via a message passing scheme. The Data Management Process acquires, compresses, and routes the incoming sensor data to other processes. The Inference Process consists of a high performance inference engine that performs a real-time analysis on the state and health of the physical system. The I/O Process receives sensor data from the Data Management Process and status messages and recommendations from the Inference Process, updates its graphical displays in real time, and acts as the interface to the console operator. The distributed architecture has been interfaced to an actual spacecraft (NASA's Hubble Space Telescope) and is able to process the incoming telemetry in real-time (i.e., several hundred data changes per second). The system is being used in two locations for different purposes: (1) in Sunnyville, California at the Space Telescope Test Control Center it is used in the preflight testing of the vehicle; and (2) in Greenbelt, Maryland at NASA/Goddard it is being used on an experimental basis in flight operations for health and safety monitoring.

Schmidt, James L.; Kao, Simon M.; Read, Jackson Y.; Weitzenkamp, Scott M.; Laffey, Thomas J.

1988-01-01

483

Interval-Based Real-Time Transmission Control  

Microsoft Academic Search

Existing cell switched and packet switched transmission systems have difficulties to support real-time data transfe r because the queuing characteristics and load variations in the network nodes are a handicap for it. With our interval-based transmission control method the data stream behavior is regulated in each network node and a data stream dependent time parameter adjustment is per- formed in

Christian Dünkel; Dietrich Reschke

1996-01-01

484

Real-Time Person Localization System with an Active Camera  

Microsoft Academic Search

This paper proposed a method in which location of a person is estimation with one active camera in real-time. The approach taken in this paper is as follows. First, we detect the person region with proposed method which is the region detection method based on short time distribution of the density to avoid the influence of the camera movement. Then

Naoya Ooshima; Takeshi Saitoh; Ryosuke Konishi

2006-01-01

485

Performance evaluation of a real time traffic sign recognition system  

Microsoft Academic Search

Traffic sign recognition has been a very active research topic for many years now. However, during this time of intensive research, no common evaluation methodology has been established. This paper explains in detail, how we evaluated our real time video-based traffic sign recognition system and thus may serve as a building block towards establishing a commonly accepted evaluation methodology. The

S. Muller-Schneiders; Christian Nunn; Mirko Meuter

2008-01-01

486

Use of mathematical morphology in real-time path planning  

Microsoft Academic Search

If an autonomous vehicle is working in an image-based system which needs real-time answers and whose response is critical, it will be very important to reduce computation times and, as we know, this could be performed by increasing the system parallelism. Since morphological filtering is the origin of several applications in computer vision, in this paper we are going to

F. A. Pujol; J. M. García Chamizo; A. Fuster; M. Pujol; R. Rizo

2002-01-01

487

Real-time pair-feeding of animals  

NASA Technical Reports Server (NTRS)

Automatic pair-feeding system was developed which immediately dispenses same amount of food to control animal as has been consumed by experimental animal that has free access to food. System consists of: master feeding system; slave feeding station; and control mechanism. Technique performs real time pair-feeding without attendant time lag.

Leon, H. A.; Connolly, J. P.; Hitchman, M. J.; Humbert, J. E.

1972-01-01

488

Real-time scheduling for energy harvesting sensor nodes  

Microsoft Academic Search

Abstract , Energy harvesting has recently emerged as a feasible option to increase the operating time of sensor networks. If each node, of the network, however, is powered by a fluctuating energy source, common power management solutions have to be reconceived., This holds in particular if real-time responsiveness of a given application has to be guaranteed. Task scheduling at the

Clemens Moser; Davide Brunelli; Lothar Thiele; Luca Benini

2007-01-01

489

A Real-Time Processor for the Hough Transform  

Microsoft Academic Search

The Hough transform method for recognition can cope effectively with noisy backgrounds and gaps in boundaries. However, long computation time and large memory requirements have prevented it from being used in real-time applications. An architecture devised to solve those problems, with a focus on detecting straight lines, is presented. Examples are given of the use of an experimental hardware model

Keishi Hanahara; Tsugito Maruyama; Takashi Uchiyama

1988-01-01

490

Workflow key to real-time claims adjudication success.  

PubMed

Real-time claims adjudication (RTCA) can help medical offices keep A/R down by facilitating collections at the time of service. RTCA requires changes in work flow, which may be hard to achieve. Accurate coding is essential to implementing RTCA. High adoption of consumer-directed health care is necessary to make implementation of RTCA practical. PMID:18782985

Bernard, Sheri Poe

2008-09-01

491

Real-time editing and relighting of homogeneous translucent materials  

Microsoft Academic Search

Existing techniques for fast, high-quality rendering of translucent materials often fix BSS- RDF parameters at precomputation time. We present a novel method for accurate rendering and relighting of translucent materials that also enables real-time editing and manipulation of homogeneous diffuse BSSRDFs. We first apply PCA analysis on diffuse multiple scattering to derive a compact basis set, consisting of only twelve

Rui Wang; Ewen Cheslack-postava; David Luebke; Qianyong Chen; Wei Hua; Qunsheng Peng; Hujun Bao

2008-01-01

492

Real-time gait event detection for paraplegic FES walking  

Microsoft Academic Search

A real-time method for the detection of gait events that occur during the electrically stimulated locomotion of paraplegic subjects is described. It consists of a two-level algorithm for the processing of sensor signals and the determination of gait event times. Sensor signals and information about the progression of the stimulator though its pre-specified stimulation \\

Margaret M. Skelly; Howard Jay Chizeck

2001-01-01

493

Real-Time, Two-Dimensional Terahertz Beam Imaging.  

National Technical Information Service (NTIS)

In ARO STTR Phase 1 program, we have demonstrated the concept and developed a real-time, two-dimensional THz wave imaging system. The THz imaging system uses electro-optic crystals and is capable of time-domain far-infrared spectroscopy across a frequency...

X. Zhang Z. Jiang

1999-01-01

494

A real time QRS complex classification method using Mahalanobis distance  

Microsoft Academic Search

An unsupervised method to recognize and classify QRS complexes was developed in order to create an automatic cardiac beat classifier in real time. After exhaustive analysis, four features extracted from the QRS complex in the time domain were selected as the ones presenting the best results: width, total sum of the areas under the positive and negative curves, total sum

J. C. T. B. Moraes; M. O. Seixas; F. N. Vilani; E. V. Costa

2002-01-01

495

DETECTION OF FECAL ENTEROCOCCI USING A REAL TIME PCR METHOD  

EPA Science Inventory

In spite of their importance in public health, the detection of fecal enterococci is performed via culturing methods that are time consuming and that are subject to inaccuracies that relate to their culturable status. In order to address these problems, a real time PCR (TaqMan) ...

496