WorldWideScience

Sample records for high bandwidth parallel

  1. High-bandwidth memory interface

    CERN Document Server

    Kim, Chulwoo; Song, Junyoung

    2014-01-01

    This book provides an overview of recent advances in memory interface design at both the architecture and circuit levels. Coverage includes signal integrity and testing, TSV interface, high-speed serial interface including equalization, ODT, pre-emphasis, wide I/O interface including crosstalk, skew cancellation, and clock generation and distribution. Trends for further bandwidth enhancement are also covered.   • Enables readers with minimal background in memory design to understand the basics of high-bandwidth memory interface design; • Presents state-of-the-art techniques for memory interface design; • Covers memory interface design at both the circuit level and system architecture level.

  2. Network Bandwidth Utilization Forecast Model on High Bandwidth Network

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Wucherl; Sim, Alex

    2014-07-07

    With the increasing number of geographically distributed scientific collaborations and the scale of the data size growth, it has become more challenging for users to achieve the best possible network performance on a shared network. We have developed a forecast model to predict expected bandwidth utilization for high-bandwidth wide area network. The forecast model can improve the efficiency of resource utilization and scheduling data movements on high-bandwidth network to accommodate ever increasing data volume for large-scale scientific data applications. Univariate model is developed with STL and ARIMA on SNMP path utilization data. Compared with traditional approach such as Box-Jenkins methodology, our forecast model reduces computation time by 83.2percent. It also shows resilience against abrupt network usage change. The accuracy of the forecast model is within the standard deviation of the monitored measurements.

  3. Network bandwidth utilization forecast model on high bandwidth networks

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Wuchert (William) [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Sim, Alex [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2015-03-30

    With the increasing number of geographically distributed scientific collaborations and the scale of the data size growth, it has become more challenging for users to achieve the best possible network performance on a shared network. We have developed a forecast model to predict expected bandwidth utilization for high-bandwidth wide area network. The forecast model can improve the efficiency of resource utilization and scheduling data movements on high-bandwidth network to accommodate ever increasing data volume for large-scale scientific data applications. Univariate model is developed with STL and ARIMA on SNMP path utilization data. Compared with traditional approach such as Box-Jenkins methodology, our forecast model reduces computation time by 83.2%. It also shows resilience against abrupt network usage change. The accuracy of the forecast model is within the standard deviation of the monitored measurements.

  4. High-Bandwidth, High-Efficiency Envelope Tracking Power Supply for 40W RF Power Amplifier Using Paralleled Bandpass Current Sources

    DEFF Research Database (Denmark)

    Høyerby, Mikkel Christian Wendelboe; Andersen, Michael Andreas E.

    2005-01-01

    This paper presents a high-performance power conversion scheme for power supply applications that require very high output voltage slew rates (dV/dt). The concept is to parallel 2 switching bandpass current sources, each optimized for its passband frequency space and the expected load current....... The principle is demonstrated with a power supply, designed for supplying a 40 W linear RF power amplifier for efficient amplification of a 16-QAM modulated data stream...

  5. High bandwidth concurrent processing on commodity platforms

    CERN Document Server

    Boosten, M; Van der Stok, P D V

    1999-01-01

    The I/O bandwidth and real-time processing power required for high- energy physics experiments is increasing rapidly over time. The current requirements can only be met by using large-scale concurrent processing. We are investigating the use of a large PC cluster interconnected by Fast and Gigabit Ethernet to meet the performance requirements of the ATLAS second level trigger. This architecture is attractive because of its performance and competitive pricing. A major problem is obtaining frequent high-bandwidth I/O without sacrificing the CPU's processing power. We present a tight integration of a user-level scheduler and a zero-copy communication layer. This system closely approaches the performance of the underlying hardware in terms of both CPU power and I/O capacity. (0 refs).

  6. RAID Disk Arrays for High Bandwidth Applications

    Science.gov (United States)

    Moren, Bill

    1996-01-01

    High bandwidth applications require large amounts of data transferred to/from storage devices at extremely high data rates. Further, these applications often are 'real time' in which access to the storage device must take place on the schedule of the data source, not the storage. A good example is a satellite downlink - the volume of data is quite large and the data rates quite high (dozens of MB/sec). Further, a telemetry downlink must take place while the satellite is overhead. A storage technology which is ideally suited to these types of applications is redundant arrays of independent discs (RAID). Raid storage technology, while offering differing methodologies for a variety of applications, supports the performance and redundancy required in real-time applications. Of the various RAID levels, RAID-3 is the only one which provides high data transfer rates under all operating conditions, including after a drive failure.

  7. Fast Faraday Cup With High Bandwidth

    Science.gov (United States)

    Deibele, Craig E [Knoxville, TN

    2006-03-14

    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.

  8. Tactical Decision Aids High Bandwidth Links Using Autonomous Vehicles

    Science.gov (United States)

    2004-01-01

    1 Tactical Decision Aids (High Bandwidth Links Using Autonomous Vehicles ) A. J. Healey, D. P. Horner, Center for Autonomous Underwater Vehicle...SUBTITLE Tactical Decision Aids (High Bandwidth Links Using Autonomous Vehicles ) 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6

  9. Bandwidth scalable, coherent transmitter based on the parallel synthesis of multiple spectral slices using optical arbitrary waveform generation.

    Science.gov (United States)

    Geisler, David J; Fontaine, Nicolas K; Scott, Ryan P; He, Tingting; Paraschis, Loukas; Gerstel, Ori; Heritage, Jonathan P; Yoo, S J B

    2011-04-25

    We demonstrate an optical transmitter based on dynamic optical arbitrary waveform generation (OAWG) which is capable of creating high-bandwidth (THz) data waveforms in any modulation format using the parallel synthesis of multiple coherent spectral slices. As an initial demonstration, the transmitter uses only 5.5 GHz of electrical bandwidth and two 10-GHz-wide spectral slices to create 100-ns duration, 20-GHz optical waveforms in various modulation formats including differential phase-shift keying (DPSK), quaternary phase-shift keying (QPSK), and eight phase-shift keying (8PSK) with only changes in software. The experimentally generated waveforms showed clear eye openings and separated constellation points when measured using a real-time digital coherent receiver. Bit-error-rate (BER) performance analysis resulted in a BER < 9.8 × 10(-6) for DPSK and QPSK waveforms. Additionally, we experimentally demonstrate three-slice, 4-ns long waveforms that highlight the bandwidth scalable nature of the optical transmitter. The various generated waveforms show that the key transmitter properties (i.e., packet length, modulation format, data rate, and modulation filter shape) are software definable, and that the optical transmitter is capable of acting as a flexible bandwidth transmitter.

  10. Review of high bandwidth fiber optics radiation sensors

    International Nuclear Information System (INIS)

    Lyons, P.B.

    1985-01-01

    This paper summarizes the use of fiber optics or guided optical systems for radiation sensors. It is limited a passive systems wherein electrical is not required at the sensor location. However, electrically powered light sources, receivers and/or recorders may still be required for detection and data storage in sensor system operation. This paper emphasizes sensor technologies that permit high bandwidth measurements of transient radiation levels, and will also discuss several low bandwidth applications. 60 refs

  11. Optical interconnect technologies for high-bandwidth ICT systems

    Science.gov (United States)

    Chujo, Norio; Takai, Toshiaki; Mizushima, Akiko; Arimoto, Hideo; Matsuoka, Yasunobu; Yamashita, Hiroki; Matsushima, Naoki

    2016-03-01

    The bandwidth of information and communication technology (ICT) systems is increasing and is predicted to reach more than 10 Tb/s. However, an electrical interconnect cannot achieve such bandwidth because of its density limits. To solve this problem, we propose two types of high-density optical fiber wiring for backplanes and circuit boards such as interface boards and switch boards. One type uses routed ribbon fiber in a circuit board because it has the ability to be formed into complex shapes to avoid interfering with the LSI and electrical components on the board. The backplane is required to exhibit high density and flexibility, so the second type uses loose fiber. We developed a 9.6-Tb/s optical interconnect demonstration system using embedded optical modules, optical backplane, and optical connector in a network apparatus chassis. We achieved 25-Gb/s transmission between FPGAs via the optical backplane.

  12. Wide bandwidth transimpedance amplifier for extremely high sensitivity continuous measurements.

    Science.gov (United States)

    Ferrari, Giorgio; Sampietro, Marco

    2007-09-01

    This article presents a wide bandwidth transimpedance amplifier based on the series of an integrator and a differentiator stage, having an additional feedback loop to discharge the standing current from the device under test (DUT) to ensure an unlimited measuring time opportunity when compared to switched discharge configurations while maintaining a large signal amplification over the full bandwidth. The amplifier shows a flat response from 0.6 Hz to 1.4 MHz, the capability to operate with leakage currents from the DUT as high as tens of nanoamperes, and rail-to-rail dynamic range for sinusoidal current signals independent of the DUT leakage current. Also available is a monitor output of the stationary current to track experimental slow drifts. The circuit is ideal for noise spectral and impedance measurements of nanodevices and biomolecules when in the presence of a physiological medium and in all cases where high sensitivity current measurements are requested such as in scanning probe microscopy systems.

  13. High bandwidth second-harmonic generation in partially deuterated KDP

    International Nuclear Information System (INIS)

    Webb, M.S.; Eimerl, D.; Velsko, S.P.

    1992-01-01

    We have experimentally determined the spectrally noncritical phasematching behavior of Type I frequency doubling in KDP and its dependence on deuteration level in partially deuterated KDP. The first order wavelength sensitivity parameter∂Δk/∂γ for Type I doubling of 1.053 μm light vanishes for a KD*P crystal with a deuteration level between 10 and 14%. Very high bandwidth frequency doubling of Nd:glass lasers is possible with such a crystal

  14. Ultra-high bandwidth quantum secured data transmission

    Science.gov (United States)

    Dynes, James F.; Tam, Winci W.-S.; Plews, Alan; Fröhlich, Bernd; Sharpe, Andrew W.; Lucamarini, Marco; Yuan, Zhiliang; Radig, Christian; Straw, Andrew; Edwards, Tim; Shields, Andrew J.

    2016-10-01

    Quantum key distribution (QKD) provides an attractive means for securing communications in optical fibre networks. However, deployment of the technology has been hampered by the frequent need for dedicated dark fibres to segregate the very weak quantum signals from conventional traffic. Up until now the coexistence of QKD with data has been limited to bandwidths that are orders of magnitude below those commonly employed in fibre optic communication networks. Using an optimised wavelength divisional multiplexing scheme, we transport QKD and the prevalent 100 Gb/s data format in the forward direction over the same fibre for the first time. We show a full quantum encryption system operating with a bandwidth of 200 Gb/s over a 100 km fibre. Exploring the ultimate limits of the technology by experimental measurements of the Raman noise, we demonstrate it is feasible to combine QKD with 10 Tb/s of data over a 50 km link. These results suggest it will be possible to integrate QKD and other quantum photonic technologies into high bandwidth data communication infrastructures, thereby allowing their widespread deployment.

  15. Managing high-bandwidth real-time data storage

    Energy Technology Data Exchange (ETDEWEB)

    Bigelow, David D. [Los Alamos National Laboratory; Brandt, Scott A [Los Alamos National Laboratory; Bent, John M [Los Alamos National Laboratory; Chen, Hsing-Bung [Los Alamos National Laboratory

    2009-09-23

    There exist certain systems which generate real-time data at high bandwidth, but do not necessarily require the long-term retention of that data in normal conditions. In some cases, the data may not actually be useful, and in others, there may be too much data to permanently retain in long-term storage whether it is useful or not. However, certain portions of the data may be identified as being vitally important from time to time, and must therefore be retained for further analysis or permanent storage without interrupting the ongoing collection of new data. We have developed a system, Mahanaxar, intended to address this problem. It provides quality of service guarantees for incoming real-time data streams and simultaneous access to already-recorded data on a best-effort basis utilizing any spare bandwidth. It has built in mechanisms for reliability and indexing, can scale upwards to meet increasing bandwidth requirements, and handles both small and large data elements equally well. We will show that a prototype version of this system provides better performance than a flat file (traditional filesystem) based version, particularly with regard to quality of service guarantees and hard real-time requirements.

  16. A wide-bandwidth and high-sensitivity robust microgyroscope

    International Nuclear Information System (INIS)

    Sahin, Korhan; Sahin, Emre; Akin, Tayfun; Alper, Said Emre

    2009-01-01

    This paper reports a microgyroscope design concept with the help of a 2 degrees of freedom (DoF) sense mode to achieve a wide bandwidth without sacrificing mechanical and electronic sensitivity and to obtain robust operation against variations under ambient conditions. The design concept is demonstrated with a tuning fork microgyroscope fabricated with an in-house silicon-on-glass micromachining process. When the fabricated gyroscope is operated with a relatively wide bandwidth of 1 kHz, measurements show a relatively high raw mechanical sensitivity of 131 µV (° s −1 ) −1 . The variation in the amplified mechanical sensitivity (scale factor) of the gyroscope is measured to be less than 0.38% for large ambient pressure variations such as from 40 to 500 mTorr. The bias instability and angle random walk of the gyroscope are measured to be 131° h −1 and 1.15° h −1/2 , respectively

  17. Development of high frequency and wide bandwidth Johnson noise thermometry

    International Nuclear Information System (INIS)

    Crossno, Jesse; Liu, Xiaomeng; Kim, Philip; Ohki, Thomas A.; Fong, Kin Chung

    2015-01-01

    We develop a high frequency, wide bandwidth radiometer operating at room temperature, which augments the traditional technique of Johnson noise thermometry for nanoscale thermal transport studies. Employing low noise amplifiers and an analog multiplier operating at 2 GHz, auto- and cross-correlated Johnson noise measurements are performed in the temperature range of 3 to 300 K, achieving a sensitivity of 5.5 mK (110 ppm) in 1 s of integration time. This setup allows us to measure the thermal conductance of a boron nitride encapsulated monolayer graphene device over a wide temperature range. Our data show a high power law (T ∼ 4) deviation from the Wiedemann-Franz law above T ∼ 100 K

  18. High Bandwidth Optical Links for Micro-Satellite Support

    Science.gov (United States)

    Chao, Tien-Hsin (Inventor); Wilson, Keith E. (Inventor); Coste, Keith (Inventor)

    2016-01-01

    A method, systems, apparatus and device enable high bandwidth satellite communications. An onboard tracking detector, installed in a low-earth orbit satellite, detects a position of an incoming optical beam received/transmitted from a first ground station of one or more ground stations. Tracker electronics determine orientation information of the incoming optical beam based on the position. Control electronics receive the orientation information from the tracker electronics, and control a waveguide drive electronics. The waveguide drive electronics control a voltage that is provided to an electro-optic waveguide beam steering device. The electro-optic waveguide beam steering device steers an outgoing optical beam to one of the one or more ground stations based on the voltage.

  19. High-bandwidth piezoresistive force probes with integrated thermal actuation

    International Nuclear Information System (INIS)

    Doll, Joseph C; Pruitt, Beth L

    2012-01-01

    We present high-speed force probes with on-chip actuation and sensing for the measurement of pN-scale forces at the microsecond timescale. We achieve a high resonant frequency in water (1–100 kHz) with requisite low spring constants (0.3–40 pN nm −1 ) and low integrated force noise (1–100 pN) by targeting probe dimensions on the order of 300 nm thick, 1–2 μm wide and 30–200 μm long. Forces are measured using silicon piezoresistors, while the probes are actuated thermally with an aluminum unimorph and silicon heater. The piezoresistive sensors are designed using the open-source numerical optimization code that incorporates constraints on operating temperature. Parylene passivation enables operation in ionic media and we demonstrate simultaneous actuation and sensing. The improved design and fabrication techniques that we describe enable a 10–20-fold improvement in force resolution or measurement bandwidth over prior piezoresistive cantilevers of comparable thickness. (paper)

  20. High bandwidth piezoresistive force probes with integrated thermal actuation

    Science.gov (United States)

    Doll, Joseph C.; Pruitt, Beth L.

    2012-01-01

    We present high-speed force probes with on-chip actuation and sensing for the measurement of pN-scale forces at the microsecond time scale. We achieve a high resonant frequency in water (1–100 kHz) with requisite low spring constants (0.3–40 pN/nm) and low integrated force noise (1–100 pN) by targeting probe dimensions on the order of 300 nm thick, 1–2 μm wide and 30–200 μm long. Forces are measured using silicon piezoresistors while the probes are actuated thermally with an aluminum unimorph and silicon heater. The piezoresistive sensors are designed using open source numerical optimization code that incorporates constraints on operating temperature. Parylene passivation enables operation in ionic media and we demonstrate simultaneous actuation and sensing. The improved design and fabrication techniques that we describe enable a 10–20 fold improvement in force resolution or measurement bandwidth over prior piezoresistive cantilevers of comparable thickness. PMID:23175616

  1. High current, high bandwidth laser diode current driver

    Science.gov (United States)

    Copeland, David J.; Zimmerman, Robert K., Jr.

    1991-01-01

    A laser diode current driver has been developed for free space laser communications. The driver provides 300 mA peak modulation current and exhibits an optical risetime of less than 400 ps. The current and optical pulses are well behaved and show minimal ringing. The driver is well suited for QPPM modulation at data rates up to 440 Mbit/s. Much previous work has championed current steering circuits; in contrast, the present driver is a single-ended on/off switch. This results in twice the power efficiency as a current steering driver. The driver electrical efficiency for QPPM data is 34 percent. The high speed switch is realized with a Ku-band GaAsFET transistor, with a suitable pre-drive circuit, on a hybrid microcircuit adjacent to the laser diode.

  2. A high control bandwidth design method for aalborg inverter under weak grid condition

    DEFF Research Database (Denmark)

    Wu, Weimin; Zhou, Cong; Wang, Houqin

    2017-01-01

    Aalborg Inverter is a kind of high efficient Buck-Boost inverter. Since it may work in “Buck-Boost” mode, the control bandwidth should be high enough to ensure a good performance under any grid condition. However, during the “Boost” operation, the control bandwidth depends much on the grid...

  3. Adaptive slope compensation for high bandwidth digital current mode controller

    DEFF Research Database (Denmark)

    Taeed, Fazel; Nymand, Morten

    2015-01-01

    An adaptive slope compensation method for digital current mode control of dc-dc converters is proposed in this paper. The compensation slope is used for stabilizing the inner current loop in peak current mode control. In this method, the compensation slope is adapted with the variations...... in converter duty cycle. The adaptive slope compensation provides optimum controller operation in term of bandwidth over wide range of operating points. In this paper operation principle of the controller is discussed. The proposed controller is implemented in an FPGA to control a 100 W buck converter...

  4. Ultra-low Noise, High Bandwidth, 1550nm HgCdTe APD, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — To meet the demands of future high-capacity free space optical communications links, a high bandwidth, near infrared (NIR), single photon sensitive optoelectronic...

  5. THz Tube Waveguides With Low Loss, Low Dispersion, and High Bandwidth

    DEFF Research Database (Denmark)

    Bao, Hualong; Nielsen, Kristian; Bang, Ole

    2014-01-01

    We propose, model and experimentally characterize a novel class of terahertz hollow-core tube waveguides with high-loss cladding material, resulting in propagation with low loss, low dispersion, and high useful bandwidth.......We propose, model and experimentally characterize a novel class of terahertz hollow-core tube waveguides with high-loss cladding material, resulting in propagation with low loss, low dispersion, and high useful bandwidth....

  6. High-speed parallel counter

    International Nuclear Information System (INIS)

    Gus'kov, B.N.; Kalinnikov, V.A.; Krastev, V.R.; Maksimov, A.N.; Nikityuk, N.M.

    1985-01-01

    This paper describes a high-speed parallel counter that contains 31 inputs and 15 outputs and is implemented by integrated circuits of series 500. The counter is designed for fast sampling of events according to the number of particles that pass simultaneously through the hodoscopic plane of the detector. The minimum delay of the output signals relative to the input is 43 nsec. The duration of the output signals can be varied from 75 to 120 nsec

  7. Knee implant imaging at 3 Tesla using high-bandwidth radiofrequency pulses.

    Science.gov (United States)

    Bachschmidt, Theresa J; Sutter, Reto; Jakob, Peter M; Pfirrmann, Christian W A; Nittka, Mathias

    2015-06-01

    To investigate the impact of high-bandwidth radiofrequency (RF) pulses used in turbo spin echo (TSE) sequences or combined with slice encoding for metal artifact correction (SEMAC) on artifact reduction at 3 Tesla in the knee in the presence of metal. Local transmit/receive coils feature increased maximum B1 amplitude, reduced SAR exposition and thus enable the application of high-bandwidth RF pulses. Susceptibility-induced through-plane distortion scales inversely with the RF bandwidth and the view angle, hence blurring, increases for higher RF bandwidths, when SEMAC is used. These effects were assessed for a phantom containing a total knee arthroplasty. TSE and SEMAC sequences with conventional and high RF bandwidths and different contrasts were tested on eight patients with different types of implants. To realize scan times of 7 to 9 min, SEMAC was always applied with eight slice-encoding steps and distortion was rated by two radiologists. A local transmit/receive knee coil enables the use of an RF bandwidth of 4 kHz compared with 850 Hz in conventional sequences. Phantom scans confirm the relation of RF bandwidth and through-plane distortion, which can be reduced up to 79%, and demonstrate the increased blurring for high-bandwidth RF pulses. In average, artifacts in this RF mode are rated hardly visible for patients with joint arthroplasties, when eight SEMAC slice-encoding steps are applied, and for patients with titanium fixtures, when TSE is used. The application of high-bandwidth RF pulses by local transmit coils substantially reduces through-plane distortion artifacts at 3 Tesla. © 2014 Wiley Periodicals, Inc.

  8. THE IMPROVEMENT OF COMPUTER NETWORK PERFORMANCE WITH BANDWIDTH MANAGEMENT IN KEMURNIAN II SENIOR HIGH SCHOOL

    Directory of Open Access Journals (Sweden)

    Bayu Kanigoro

    2012-05-01

    Full Text Available This research describes the improvement of computer network performance with bandwidth management in Kemurnian II Senior High School. The main issue of this research is the absence of bandwidth division on computer, which makes user who is downloading data, the provided bandwidth will be absorbed by the user. It leads other users do not get the bandwidth. Besides that, it has been done IP address division on each room, such as computer, teacher and administration room for supporting learning process in Kemurnian II Senior High School, so wireless network is needed. The method is location observation and interview with related parties in Kemurnian II Senior High School, the network analysis has run and designed a new topology network including the wireless network along with its configuration and separation bandwidth on microtic router and its limitation. The result is network traffic on Kemurnian II Senior High School can be shared evenly to each user; IX and IIX traffic are separated, which improve the speed on network access at school and the implementation of wireless network.Keywords: Bandwidth Management; Wireless Network

  9. High modulation bandwidth of a light-emitting diode with surface plasmon coupling (Conference Presentation)

    Science.gov (United States)

    Lin, Chun-Han; Tu, Charng-Gan; Yao, Yu-Feng; Chen, Sheng-Hung; Su, Chia-Ying; Chen, Hao-Tsung; Kiang, Yean-Woei; Yang, Chih-Chung

    2017-02-01

    Besides lighting, LEDs can be used for indoor data transmission. Therefore, a large modulation bandwidth becomes an important target in the development of visible LED. In this regard, enhancing the radiative recombination rate of carriers in the quantum wells of an LED is a useful method since the modulation bandwidth of an LED is related to the carrier decay rate besides the device RC time constant To increase the carrier decay rate in an LED without sacrificing its output power, the technique of surface plasmon (SP) coupling in an LED is useful. In this paper, the increases of modulation bandwidth by reducing mesa size, decreasing active layer thickness, and inducing SP coupling in blue- and green-emitting LEDs are illustrated. The results are demonstrated by comparing three different LED surface structures, including bare p-type surface, GaZnO current spreading layer, and Ag nanoparticles (NPs) for inducing SP coupling. In a single-quantum-well, blue-emitting LED with a circular mesa of 10 microns in radius, SP coupling results in a modulation bandwidth of 528.8 MHz, which is believed to be the record-high level. A smaller RC time constant can lead to a higher modulation bandwidth. However, when the RC time constant is smaller than 0.2 ns, its effect on modulation bandwidth saturates. The dependencies of modulation bandwidth on injected current density and carrier decay time confirm that the modulation bandwidth is essentially inversely proportional to a time constant, which is inversely proportional to the square-root of carrier decay rate and injected current density.

  10. Extremelly High Bandwidth Rad Hard Data Acquisition System, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Advancements in sensors/detectors are needed to support future NASA mission concepts including polarimetry, large format imaging arrays, and high-sensitivity...

  11. Extremelly High Bandwidth Rad Hard Data Acquisition System, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Analog-to-digital converters (ADCs) are the key components for digitizing high-speed analog data in modern data acquisition systems, which is a critical part of...

  12. Towards realising high-speed large-bandwidth quantum memory

    Institute of Scientific and Technical Information of China (English)

    SHI BaoSen; DING DongSheng

    2016-01-01

    Indispensable for quantum communication and quantum computation,quantum memory executes on demand storage and retrieval of quantum states such as those of a single photon,an entangled pair or squeezed states.Among the various forms of quantum memory,Raman quantum memory has advantages forits broadband and high-speed characteristics,which results in a huge potential for applications in quantum networks and quantum computation.However,realising Raman quantum memory with true single photons and photonic entanglementis challenging.In this review,after briefly introducing the main benchmarks in the development of quantum memory and describing the state of the art,we focus on our recent experimental progress inquantum memorystorage of quantum states using the Raman scheme.

  13. High Dielectric Low Loss Transparent Glass Material Based Dielectric Resonator Antenna with Wide Bandwidth Operation

    Science.gov (United States)

    Mehmood, Arshad; Zheng, Yuliang; Braun, Hubertus; Hovhannisyan, Martun; Letz, Martin; Jakoby, Rolf

    2015-01-01

    This paper presents the application of new high permittivity and low loss glass material for antennas. This glass material is transparent. A very simple rectangular dielectric resonator antenna is designed first with a simple microstrip feeding line. In order to widen the bandwidth, the feed of the design is modified by forming a T-shaped feeding. This new design enhanced the bandwidth range to cover the WLAN 5 GHz band completely. The dielectric resonator antenna cut into precise dimensions is placed on the modified microstrip feed line. The design is simple and easy to manufacture and also very compact in size of only 36 × 28 mm. A -10 dB impedance bandwidth of 18% has been achieved, which covers the frequency range from 5.15 GHz to 5.95 GHz. Simulations of the measured return loss and radiation patterns are presented and discussed.

  14. High efficiency and broad bandwidth grating coupler between nanophotonic waveguide and fibre

    International Nuclear Information System (INIS)

    Yu, Zhu; Xue-Jun, Xu; Zhi-Yong, Li; Liang, Zhou; Yu-De, Yu; Jin-Zhong, Yu; Wei-Hua, Han; Zhong-Chao, Fan

    2010-01-01

    A high efficiency and broad bandwidth grating coupler between a silicon-on-insulator (SOI) nanophotonic waveguide and fibre is designed and fabricated. Coupling efficiencies of 46% and 25% at a wavelength of 1.55 μm are achieved by simulation and experiment, respectively. An optical 3 dB bandwidth of 45 nm from 1530 nm to 1575 nm is also obtained in experiment. Numerical calculation shows that a tolerance to fabrication error of 10 nm in etch depth is achievable. The measurement results indicate that the alignment error of ±2 μm results in less than 1 dB additional coupling loss. (classical areas of phenomenology)

  15. Optical Characteristics of a Multichannel Hybrid Integrated Light Source for Ultra-High-Bandwidth Optical Interconnections

    Directory of Open Access Journals (Sweden)

    Takanori Shimizu

    2015-11-01

    Full Text Available The optical characteristics of a multi-channel hybrid integrated light source were described for an optical interconnection with a bandwidth of over 10 Tbit/s. The power uniformity of the relative intensity of a 1000-channel light source was shown, and the minimum standard deviation s of the optical power of the 200 output ports at each 25-channel laser diode (LD array was estimated to be 0.49 dB. This hybrid integrated light source is expected to be easily adaptable to a photonics-electronics convergence system for ultra-high-bandwidth interchip interconnections.

  16. High-bandwidth and flexible tracking control for precision motion with application to a piezo nanopositioner.

    Science.gov (United States)

    Feng, Zhao; Ling, Jie; Ming, Min; Xiao, Xiao-Hui

    2017-08-01

    For precision motion, high-bandwidth and flexible tracking are the two important issues for significant performance improvement. Iterative learning control (ILC) is an effective feedforward control method only for systems that operate strictly repetitively. Although projection ILC can track varying references, the performance is still limited by the fixed-bandwidth Q-filter, especially for triangular waves tracking commonly used in a piezo nanopositioner. In this paper, a wavelet transform-based linear time-varying (LTV) Q-filter design for projection ILC is proposed to compensate high-frequency errors and improve the ability to tracking varying references simultaneously. The LVT Q-filter is designed based on the modulus maximum of wavelet detail coefficients calculated by wavelet transform to determine the high-frequency locations of each iteration with the advantages of avoiding cross-terms and segmenting manually. The proposed approach was verified on a piezo nanopositioner. Experimental results indicate that the proposed approach can locate the high-frequency regions accurately and achieve the best performance under varying references compared with traditional frequency-domain and projection ILC with a fixed-bandwidth Q-filter, which validates that through implementing the LTV filter on projection ILC, high-bandwidth and flexible tracking can be achieved simultaneously by the proposed approach.

  17. High Bandwidth Communications Links Between Heterogeneous Autonomous Vehicles Using Sensor Network Modeling and Extremum Control Approaches

    Science.gov (United States)

    2008-12-01

    In future network-centric warfare environments, teams of autonomous vehicles will be deployed in a coorperative manner to conduct wide-area...of data back to the command station, autonomous vehicles configured with high bandwidth communication system are positioned between the command

  18. Highly-Integrated Hydraulic Smart Actuators and Smart Manifolds for High-Bandwidth Force Control

    Directory of Open Access Journals (Sweden)

    Victor Barasuol

    2018-06-01

    Full Text Available Hydraulic actuation is the most widely used alternative to electric motors for legged robots and manipulators. It is often selected for its high power density, robustness and high-bandwidth control performance that allows the implementation of force/impedance control. Force control is crucial for robots that are in contact with the environment, since it enables the implementation of active impedance and whole body control that can lead to a better performance in known and unknown environments. This paper presents the hydraulic Integrated Smart Actuator (ISA developed by Moog in collaboration with IIT, as well as smart manifolds for rotary hydraulic actuators. The ISA consists of an additive-manufactured body containing a hydraulic cylinder, servo valve, pressure/position/load/temperature sensing, overload protection and electronics for control and communication. The ISA v2 and ISA v5 have been specifically designed to fit into the legs of IIT’s hydraulic quadruped robots HyQ and HyQ-REAL, respectively. The key features of these components tackle 3 of today’s main challenges of hydraulic actuation for legged robots through: (1 built-in controllers running inside integrated electronics for high-performance control, (2 low-leakage servo valves for reduced energy losses, and (3 compactness thanks to metal additive manufacturing. The main contributions of this paper are the derivation of the representative dynamic models of these highly integrated hydraulic servo actuators, a control architecture that allows for high-bandwidth force control and their experimental validation with application-specific trajectories and tests. We believe that this is the first work that presents additive-manufactured, highly integrated hydraulic smart actuators for robotics.

  19. High performance parallel I/O

    CERN Document Server

    Prabhat

    2014-01-01

    Gain Critical Insight into the Parallel I/O EcosystemParallel I/O is an integral component of modern high performance computing (HPC), especially in storing and processing very large datasets to facilitate scientific discovery. Revealing the state of the art in this field, High Performance Parallel I/O draws on insights from leading practitioners, researchers, software architects, developers, and scientists who shed light on the parallel I/O ecosystem.The first part of the book explains how large-scale HPC facilities scope, configure, and operate systems, with an emphasis on choices of I/O har

  20. High-fidelity polarization storage in a gigahertz bandwidth quantum memory

    International Nuclear Information System (INIS)

    England, D G; Michelberger, P S; Champion, T F M; Reim, K F; Lee, K C; Sprague, M R; Jin, X-M; Langford, N K; Kolthammer, W S; Nunn, J; Walmsley, I A

    2012-01-01

    We demonstrate a dual-rail optical Raman memory inside a polarization interferometer; this enables us to store polarization-encoded information at GHz bandwidths in a room-temperature atomic ensemble. By performing full process tomography on the system, we measure up to 97 ± 1% process fidelity for the storage and retrieval process. At longer storage times, the process fidelity remains high, despite a loss of efficiency. The fidelity is 86 ± 4% for 1.5 μs storage time, which is 5000 times the pulse duration. Hence, high fidelity is combined with a large time-bandwidth product. This high performance, with an experimentally simple setup, demonstrates the suitability of the Raman memory for integration into large-scale quantum networks. (paper)

  1. In-circuit-measurement of parasitic elements in high gain high bandwidth low noise transimpedance amplifiers.

    Science.gov (United States)

    Cochems, P; Kirk, A; Zimmermann, S

    2014-12-01

    Parasitic elements play an important role in the development of every high performance circuit. In the case of high gain, high bandwidth transimpedance amplifiers, the most important parasitic elements are parasitic capacitances at the input and in the feedback path, which significantly influence the stability, the frequency response, and the noise of the amplifier. As these parasitic capacitances range from a few picofarads down to only a few femtofarads, it is nearly impossible to measure them accurately using traditional LCR meters. Unfortunately, they also cannot be easily determined from the transfer function of the transimpedance amplifier, as it contains several overlapping effects and its measurement is only possible when the circuit is already stable. Therefore, we developed an in-circuit measurement method utilizing minimal modifications to the input stage in order to measure its parasitic capacitances directly and with unconditional stability. Furthermore, using the data acquired with this measurement technique, we both proposed a model for the complicated frequency response of high value thick film resistors as they are used in high gain transimpedance amplifiers and optimized our transimpedance amplifier design.

  2. Cavity resonance absorption in ultra-high bandwidth CRT deflection structure by a resistive load

    Science.gov (United States)

    Dunham, M.E.; Hudson, C.L.

    1993-05-11

    An improved ultra-high bandwidth helical coil deflection structure for a cathode ray tube is described comprising a first metal member having a bore therein, the metal walls of which form a first ground plane; a second metal member coaxially mounted in the bore of the first metal member and forming a second ground plane; a helical deflection coil coaxially mounted within the bore between the two ground planes; and a resistive load disposed in one end of the bore and electrically connected to the first and second ground planes, the resistive load having an impedance substantially equal to the characteristic impedance of the coaxial line formed by the two coaxial ground planes to inhibit cavity resonance in the structure within the ultra-high bandwidth of operation. Preferably, the resistive load comprises a carbon film on a surface of an end plug in one end of the bore.

  3. Pickup design for high bandwidth bunch arrival-time monitors in free-electron lasers

    Energy Technology Data Exchange (ETDEWEB)

    Angelovski, Aleksandar; Penirschke, Andreas; Jakoby, Rolf [TU Darmstadt (Germany). Institut fuer Mikrowellentechnik und Photonik; Kuhl, Alexander; Schnepp, Sascha [TU Darmstadt (Germany). Graduate School of Computational Engineering; Bock, Marie Kristin; Bousonville, Michael; Schlarb, Holger [Deutsches Elektronen-Synchrotron DESY, Hamburg (Germany); Weiland, Thomas [TU Darmstadt (Germany). Institut fuer Theorie Elektromagnetischer Felder

    2012-07-01

    The increased demands for low bunch charge operation mode in the free-electron lasers (FELs) require an upgrade of the existing synchronization equipment. As a part of the laser-based synchronization system, the bunch arrival-time monitors (BAMs) should have a sub-10 femtosecond precision for high and low bunch charge operation. In order to fulfill the resolution demands for both modes of operation, the bandwidth of such a BAM should be increased up to a cutoff frequency of 40 GHz. In this talk, we present the design and the realization of high bandwidth cone-shaped pickup electrodes as a part of the BAM for the FEL in Hamburg (FLASH) and the European X-ray free-electron laser (European XFEL). The proposed pickup was simulated with CST STUDIO SUITE, and a non-hermetic model was built up for radio frequency (rf) measurements.

  4. High-Bandwidth Dynamic Full-Field Profilometry for Nano-Scale Characterization of MEMS

    International Nuclear Information System (INIS)

    Chen, L-C; Huang, Y-T; Chang, P-B

    2006-01-01

    The article describes an innovative optical interferometric methodology to delivery dynamic surface profilometry with a measurement bandwidth up to 10MHz or higher and a vertical resolution up to 1 nm. Previous work using stroboscopic microscopic interferometry for dynamic characterization of micro (opto)electromechanical systems (M(O)EMS) has been limited in measurement bandwidth mainly within a couple of MHz. For high resonant mode analysis, the stroboscopic light pulse is insufficiently short to capture the moving fringes from dynamic motion of the detected structure. In view of this need, a microscopic prototype based on white-light stroboscopic interferometry with an innovative light superposition strategy was developed to achieve dynamic full-field profilometry with a high measurement bandwidth up to 10MHz or higher. The system primarily consists of an optical microscope, on which a Mirau interferometric objective embedded with a piezoelectric vertical translator, a high-power LED light module with dual operation modes and light synchronizing electronics unit are integrated. A micro cantilever beam used in AFM was measured to verify the system capability in accurate characterisation of dynamic behaviours of the device. The full-field seventh-mode vibration at a vibratory frequency of 3.7MHz can be fully characterized and nano-scale vertical measurement resolution as well as tens micrometers of vertical measurement range can be performed

  5. High-Bandwidth Dynamic Full-Field Profilometry for Nano-Scale Characterization of MEMS

    Energy Technology Data Exchange (ETDEWEB)

    Chen, L-C [Graduate Institute of Automation Technology, National Taipei University of Technology, 1 Sec. 3 Chung-Hsiao East Rd., Taipei, 106, Taiwan (China); Huang, Y-T [Graduate Institute of Automation Technology, National Taipei University of Technology, 1 Sec. 3 Chung-Hsiao East Rd., Taipei, 106, Taiwan (China); Chang, P-B [Graduate Institute of Mechanical and Electrical Engineering, National Taipei University of Technology, 1 Sec. 3 Chung-Hsiao East Rd., Taipei, 106, Taiwan (China)

    2006-10-15

    The article describes an innovative optical interferometric methodology to delivery dynamic surface profilometry with a measurement bandwidth up to 10MHz or higher and a vertical resolution up to 1 nm. Previous work using stroboscopic microscopic interferometry for dynamic characterization of micro (opto)electromechanical systems (M(O)EMS) has been limited in measurement bandwidth mainly within a couple of MHz. For high resonant mode analysis, the stroboscopic light pulse is insufficiently short to capture the moving fringes from dynamic motion of the detected structure. In view of this need, a microscopic prototype based on white-light stroboscopic interferometry with an innovative light superposition strategy was developed to achieve dynamic full-field profilometry with a high measurement bandwidth up to 10MHz or higher. The system primarily consists of an optical microscope, on which a Mirau interferometric objective embedded with a piezoelectric vertical translator, a high-power LED light module with dual operation modes and light synchronizing electronics unit are integrated. A micro cantilever beam used in AFM was measured to verify the system capability in accurate characterisation of dynamic behaviours of the device. The full-field seventh-mode vibration at a vibratory frequency of 3.7MHz can be fully characterized and nano-scale vertical measurement resolution as well as tens micrometers of vertical measurement range can be performed.

  6. High-speed 405-nm superluminescent diode (SLD) with 807-MHz modulation bandwidth

    KAUST Repository

    Shen, Chao

    2016-08-25

    III-nitride LEDs are fundamental components for visible-light communication (VLC). However, the modulation bandwidth is inherently limited by the relatively long carrier lifetime. In this letter, we present the 405 nm emitting superluminescent diode (SLD) with tilted facet design on semipolar GaN substrate, showing a broad emission of ∼9 nm at 20 mW optical power. Owing to the fast recombination (τ<0.35 ns) through the amplified spontaneous emission, the SLD exhibits a significantly large 3-dB bandwidth of 807 MHz. A data rate of 1.3 Gbps with a bit-error rate of 2.9 × 10 was obtained using on-off keying modulation scheme, suggesting the SLD being a high-speed transmitter for VLC applications.

  7. High-speed 405-nm superluminescent diode (SLD) with 807-MHz modulation bandwidth

    KAUST Repository

    Shen, Chao; Lee, Changmin; Ng, Tien Khee; Nakamura, Shuji; Speck, James S.; DenBaars, Steven P.; Alyamani, Ahmed Y.; El-Desouki, Munir M.; Ooi, Boon S.

    2016-01-01

    III-nitride LEDs are fundamental components for visible-light communication (VLC). However, the modulation bandwidth is inherently limited by the relatively long carrier lifetime. In this letter, we present the 405 nm emitting superluminescent diode (SLD) with tilted facet design on semipolar GaN substrate, showing a broad emission of ∼9 nm at 20 mW optical power. Owing to the fast recombination (τ<0.35 ns) through the amplified spontaneous emission, the SLD exhibits a significantly large 3-dB bandwidth of 807 MHz. A data rate of 1.3 Gbps with a bit-error rate of 2.9 × 10 was obtained using on-off keying modulation scheme, suggesting the SLD being a high-speed transmitter for VLC applications.

  8. Bandwidth Limitations in Characterization of High Intensity Focused Ultrasound Fields in the Presence of Shocks

    Science.gov (United States)

    Khokhlova, V. A.; Bessonova, O. V.; Soneson, J. E.; Canney, M. S.; Bailey, M. R.; Crum, L. A.

    2010-03-01

    Nonlinear propagation effects result in the formation of weak shocks in high intensity focused ultrasound (HIFU) fields. When shocks are present, the wave spectrum consists of hundreds of harmonics. In practice, shock waves are modeled using a finite number of harmonics and measured with hydrophones that have limited bandwidths. The goal of this work was to determine how many harmonics are necessary to model or measure peak pressures, intensity, and heat deposition rates of the HIFU fields. Numerical solutions of the Khokhlov-Zabolotskaya-Kuznetzov-type (KZK) nonlinear parabolic equation were obtained using two independent algorithms, compared, and analyzed for nonlinear propagation in water, in gel phantom, and in tissue. Measurements were performed in the focus of the HIFU field in the same media using fiber optic probe hydrophones of various bandwidths. Experimental data were compared to the simulation results.

  9. A HIGH BANDWIDTH BIPOLAR POWER SUPPLY FOR THE FAST CORRECTORS IN THE APS UPGRADE*

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Ju; Sprau, Gary

    2017-06-25

    The APS Upgrade of a multi-bend achromat (MBA) storage ring requires a fast bipolar power supply for the fast correction magnets. The key performance requirement of the power supply includes a small-signal bandwidth of 10 kHz for the output current. This requirement presents a challenge to the design because of the high inductance of the magnet load and a limited input DC voltage. A prototype DC/DC power supply utilizing a MOSFET H-bridge circuit with a 500 kHz PWM has been developed and tested successfully. The prototype achieved a 10-kHz bandwidth with less than 3-dB attenuation for a signal 0.5% of the maximum operating current of 15 amperes. This paper presents the design of the power circuit, the PWM method, the control loop, and the test results.

  10. ICE-Based Custom Full-Mesh Network for the CHIME High Bandwidth Radio Astronomy Correlator

    Science.gov (United States)

    Bandura, K.; Cliche, J. F.; Dobbs, M. A.; Gilbert, A. J.; Ittah, D.; Mena Parra, J.; Smecher, G.

    2016-03-01

    New generation radio interferometers encode signals from thousands of antenna feeds across large bandwidth. Channelizing and correlating this data requires networking capabilities that can handle unprecedented data rates with reasonable cost. The Canadian Hydrogen Intensity Mapping Experiment (CHIME) correlator processes 8-bits from N=2,048 digitizer inputs across 400MHz of bandwidth. Measured in N2× bandwidth, it is the largest radio correlator that is currently commissioning. Its digital back-end must exchange and reorganize the 6.6terabit/s produced by its 128 digitizing and channelizing nodes, and feed it to the 256 graphics processing unit (GPU) node spatial correlator in a way that each node obtains data from all digitizer inputs but across a small fraction of the bandwidth (i.e. ‘corner-turn’). In order to maximize performance and reliability of the corner-turn system while minimizing cost, a custom networking solution has been implemented. The system makes use of Field Programmable Gate Array (FPGA) transceivers to implement direct, passive copper, full-mesh, high speed serial connections between sixteen circuit boards in a crate, to exchange data between crates, and to offload the data to a cluster of 256 GPU nodes using standard 10Gbit/s Ethernet links. The GPU nodes complete the corner-turn by combining data from all crates and then computing visibilities. Eye diagrams and frame error counters confirm error-free operation of the corner-turn network in both the currently operating CHIME Pathfinder telescope (a prototype for the full CHIME telescope) and a representative fraction of the full CHIME hardware providing an end-to-end system validation. An analysis of an equivalent corner-turn system built with Ethernet switches instead of custom passive data links is provided.

  11. Applied techniques for high bandwidth data transfers across wide area networks

    International Nuclear Information System (INIS)

    Lee, J.; Gunter, D.; Tierney, B.; Allcock, B.; Bester, J.; Bresnahan, J.; Tuecke, S.

    2001-01-01

    Large distributed systems such as Computational/Data Grids require large amounts of data to be co-located with the computing facilities for processing. From their work developing a scalable distributed network cache, the authors have gained experience with techniques necessary to achieve high data throughput over high bandwidth Wide Area Networks (WAN). The authors discuss several hardware and software design techniques, and then describe their application to an implementation of an enhanced FTP protocol called GridFTP. The authors describe results from the Supercomputing 2000 conference

  12. High performance parallel computers for science

    International Nuclear Information System (INIS)

    Nash, T.; Areti, H.; Atac, R.; Biel, J.; Cook, A.; Deppe, J.; Edel, M.; Fischler, M.; Gaines, I.; Hance, R.

    1989-01-01

    This paper reports that Fermilab's Advanced Computer Program (ACP) has been developing cost effective, yet practical, parallel computers for high energy physics since 1984. The ACP's latest developments are proceeding in two directions. A Second Generation ACP Multiprocessor System for experiments will include $3500 RISC processors each with performance over 15 VAX MIPS. To support such high performance, the new system allows parallel I/O, parallel interprocess communication, and parallel host processes. The ACP Multi-Array Processor, has been developed for theoretical physics. Each $4000 node is a FORTRAN or C programmable pipelined 20 Mflops (peak), 10 MByte single board computer. These are plugged into a 16 port crossbar switch crate which handles both inter and intra crate communication. The crates are connected in a hypercube. Site oriented applications like lattice gauge theory are supported by system software called CANOPY, which makes the hardware virtually transparent to users. A 256 node, 5 GFlop, system is under construction

  13. Re-use of Low Bandwidth Equipment for High Bit Rate Transmission Using Signal Slicing Technique

    DEFF Research Database (Denmark)

    Wagner, Christoph; Spolitis, S.; Vegas Olmos, Juan José

    : Massive fiber-to-the-home network deployment requires never ending equipment upgrades operating at higher bandwidth. We show effective signal slicing method, which can reuse low bandwidth opto-electronical components for optical communications at higher bit rates.......: Massive fiber-to-the-home network deployment requires never ending equipment upgrades operating at higher bandwidth. We show effective signal slicing method, which can reuse low bandwidth opto-electronical components for optical communications at higher bit rates....

  14. Bandwidth-limited control and ringdown suppression in high-Q resonators.

    Science.gov (United States)

    Borneman, Troy W; Cory, David G

    2012-12-01

    We describe how the transient behavior of a tuned and matched resonator circuit and a ringdown suppression pulse may be integrated into an optimal control theory (OCT) pulse-design algorithm to derive control sequences with limited ringdown that perform a desired quantum operation in the presence of resonator distortions of the ideal waveform. Inclusion of ringdown suppression in numerical pulse optimizations significantly reduces spectrometer deadtime when using high quality factor (high-Q) resonators, leading to increased signal-to-noise ratio (SNR) and sensitivity of inductive measurements. To demonstrate the method, we experimentally measure the free-induction decay of an inhomogeneously broadened solid-state free radical spin system at high Q. The measurement is enabled by using a numerically optimized bandwidth-limited OCT pulse, including ringdown suppression, robust to variations in static and microwave field strengths. We also discuss the applications of pulse design in high-Q resonators to universal control of anisotropic-hyperfine coupled electron-nuclear spin systems via electron-only modulation even when the bandwidth of the resonator is significantly smaller than the hyperfine coupling strength. These results demonstrate how limitations imposed by linear response theory may be vastly exceeded when using a sufficiently accurate system model to optimize pulses of high complexity. Copyright © 2012 Elsevier Inc. All rights reserved.

  15. APEnet+: high bandwidth 3D torus direct network for petaflops scale commodity clusters

    International Nuclear Information System (INIS)

    Ammendola, R; Salamon, A; Salina, G; Biagioni, A; Prezza, O; Cicero, F Lo; Lonardo, A; Paolucci, P S; Rossetti, D; Tosoratto, L; Vicini, P; Simula, F

    2011-01-01

    We describe herein the APElink+ board, a PCIe interconnect adapter featuring the latest advances in wire speed and interface technology plus hardware support for a RDMA programming model and experimental acceleration of GPU networking; this design allows us to build a low latency, high bandwidth PC cluster, the APEnet+ network, the new generation of our cost-effective, tens-of-thousands-scalable cluster network architecture. Some test results and characterization of data transmission of a complete testbench, based on a commercial development card mounting an Altera ® FPGA, are provided.

  16. APEnet+: high bandwidth 3D torus direct network for petaflops scale commodity clusters

    Energy Technology Data Exchange (ETDEWEB)

    Ammendola, R; Salamon, A; Salina, G [INFN Tor Vergata, Roma (Italy); Biagioni, A; Prezza, O; Cicero, F Lo; Lonardo, A; Paolucci, P S; Rossetti, D; Tosoratto, L; Vicini, P [INFN Roma, Roma (Italy); Simula, F [Sapienza Universita di Roma, Roma (Italy)

    2011-12-23

    We describe herein the APElink+ board, a PCIe interconnect adapter featuring the latest advances in wire speed and interface technology plus hardware support for a RDMA programming model and experimental acceleration of GPU networking; this design allows us to build a low latency, high bandwidth PC cluster, the APEnet+ network, the new generation of our cost-effective, tens-of-thousands-scalable cluster network architecture. Some test results and characterization of data transmission of a complete testbench, based on a commercial development card mounting an Altera{sup Registered-Sign} FPGA, are provided.

  17. Three-Axis Attitude Estimation With a High-Bandwidth Angular Rate Sensor

    Science.gov (United States)

    Bayard, David S.; Green, Joseph J.

    2013-01-01

    A continuing challenge for modern instrument pointing control systems is to meet the increasingly stringent pointing performance requirements imposed by emerging advanced scientific, defense, and civilian payloads. Instruments such as adaptive optics telescopes, space interferometers, and optical communications make unprecedented demands on precision pointing capabilities. A cost-effective method was developed for increasing the pointing performance for this class of NASA applications. The solution was to develop an attitude estimator that fuses star tracker and gyro measurements with a high-bandwidth angular rotation sensor (ARS). An ARS is a rate sensor whose bandwidth extends well beyond that of the gyro, typically up to 1,000 Hz or higher. The most promising ARS sensor technology is based on a magnetohydrodynamic concept, and has recently become available commercially. The key idea is that the sensor fusion of the star tracker, gyro, and ARS provides a high-bandwidth attitude estimate suitable for supporting pointing control with a fast-steering mirror or other type of tip/tilt correction for increased performance. The ARS is relatively inexpensive and can be bolted directly next to the gyro and star tracker on the spacecraft bus. The high-bandwidth attitude estimator fuses an ARS sensor with a standard three-axis suite comprised of a gyro and star tracker. The estimation architecture is based on a dual-complementary filter (DCF) structure. The DCF takes a frequency- weighted combination of the sensors such that each sensor is most heavily weighted in a frequency region where it has the lowest noise. An important property of the DCF is that it avoids the need to model disturbance torques in the filter mechanization. This is important because the disturbance torques are generally not known in applications. This property represents an advantage over the prior art because it overcomes a weakness of the Kalman filter that arises when fusing more than one rate

  18. Engineering the CernVM-Filesystem as a High Bandwidth Distributed Filesystem for Auxiliary Physics Data

    Science.gov (United States)

    Dykstra, D.; Bockelman, B.; Blomer, J.; Herner, K.; Levshina, T.; Slyz, M.

    2015-12-01

    A common use pattern in the computing models of particle physics experiments is running many distributed applications that read from a shared set of data files. We refer to this data is auxiliary data, to distinguish it from (a) event data from the detector (which tends to be different for every job), and (b) conditions data about the detector (which tends to be the same for each job in a batch of jobs). Relatively speaking, conditions data also tends to be relatively small per job where both event data and auxiliary data are larger per job. Unlike event data, auxiliary data comes from a limited working set of shared files. Since there is spatial locality of the auxiliary data access, the use case appears to be identical to that of the CernVM- Filesystem (CVMFS). However, we show that distributing auxiliary data through CVMFS causes the existing CVMFS infrastructure to perform poorly. We utilize a CVMFS client feature called "alien cache" to cache data on existing local high-bandwidth data servers that were engineered for storing event data. This cache is shared between the worker nodes at a site and replaces caching CVMFS files on both the worker node local disks and on the site's local squids. We have tested this alien cache with the dCache NFSv4.1 interface, Lustre, and the Hadoop Distributed File System (HDFS) FUSE interface, and measured performance. In addition, we use high-bandwidth data servers at central sites to perform the CVMFS Stratum 1 function instead of the low-bandwidth web servers deployed for the CVMFS software distribution function. We have tested this using the dCache HTTP interface. As a result, we have a design for an end-to-end high-bandwidth distributed caching read-only filesystem, using existing client software already widely deployed to grid worker nodes and existing file servers already widely installed at grid sites. Files are published in a central place and are soon available on demand throughout the grid and cached locally on the

  19. Engineering the CernVM-Filesystem as a High Bandwidth Distributed Filesystem for Auxiliary Physics Data

    Energy Technology Data Exchange (ETDEWEB)

    Dykstra, D. [Fermilab; Bockelman, B. [Nebraska U.; Blomer, J. [CERN; Herner, K. [Fermilab; Levshina, T. [Fermilab; Slyz, M. [Fermilab

    2015-12-23

    A common use pattern in the computing models of particle physics experiments is running many distributed applications that read from a shared set of data files. We refer to this data is auxiliary data, to distinguish it from (a) event data from the detector (which tends to be different for every job), and (b) conditions data about the detector (which tends to be the same for each job in a batch of jobs). Relatively speaking, conditions data also tends to be relatively small per job where both event data and auxiliary data are larger per job. Unlike event data, auxiliary data comes from a limited working set of shared files. Since there is spatial locality of the auxiliary data access, the use case appears to be identical to that of the CernVM- Filesystem (CVMFS). However, we show that distributing auxiliary data through CVMFS causes the existing CVMFS infrastructure to perform poorly. We utilize a CVMFS client feature called 'alien cache' to cache data on existing local high-bandwidth data servers that were engineered for storing event data. This cache is shared between the worker nodes at a site and replaces caching CVMFS files on both the worker node local disks and on the site's local squids. We have tested this alien cache with the dCache NFSv4.1 interface, Lustre, and the Hadoop Distributed File System (HDFS) FUSE interface, and measured performance. In addition, we use high-bandwidth data servers at central sites to perform the CVMFS Stratum 1 function instead of the low-bandwidth web servers deployed for the CVMFS software distribution function. We have tested this using the dCache HTTP interface. As a result, we have a design for an end-to-end high-bandwidth distributed caching read-only filesystem, using existing client software already widely deployed to grid worker nodes and existing file servers already widely installed at grid sites. Files are published in a central place and are soon available on demand throughout the grid and cached

  20. Small-angle scattering of polychromatic X-rays: effects of bandwidth, spectral shape and high harmonics

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Sen; Luo, Sheng-Nian

    2018-02-16

    Polychromatic X-ray sources can be useful for photon-starved small-angle X-ray scattering given their high spectral fluxes. Their bandwidths, however, are 10–100 times larger than those using monochromators. To explore the feasibility, ideal scattering curves of homogeneous spherical particles for polychromatic X-rays are calculated and analyzed using the Guinier approach, maximum entropy and regularization methods. Monodisperse and polydisperse systems are explored. The influence of bandwidth and asymmetric spectra shape are exploredviaGaussian and half-Gaussian spectra. Synchrotron undulator spectra represented by two undulator sources of the Advanced Photon Source are examined as an example, as regards the influence of asymmetric harmonic shape, fundamental harmonic bandwidth and high harmonics. The effects of bandwidth, spectral shape and high harmonics on particle size determination are evaluated quantitatively.

  1. Small-angle scattering of polychromatic X-rays: effects of bandwidth, spectral shape and high harmonics.

    Science.gov (United States)

    Chen, Sen; Luo, Sheng Nian

    2018-03-01

    Polychromatic X-ray sources can be useful for photon-starved small-angle X-ray scattering given their high spectral fluxes. Their bandwidths, however, are 10-100 times larger than those using monochromators. To explore the feasibility, ideal scattering curves of homogeneous spherical particles for polychromatic X-rays are calculated and analyzed using the Guinier approach, maximum entropy and regularization methods. Monodisperse and polydisperse systems are explored. The influence of bandwidth and asymmetric spectra shape are explored via Gaussian and half-Gaussian spectra. Synchrotron undulator spectra represented by two undulator sources of the Advanced Photon Source are examined as an example, as regards the influence of asymmetric harmonic shape, fundamental harmonic bandwidth and high harmonics. The effects of bandwidth, spectral shape and high harmonics on particle size determination are evaluated quantitatively.

  2. Mahanaxar: quality of service guarantees in high-bandwidth, real-time streaming data storage

    Energy Technology Data Exchange (ETDEWEB)

    Bigelow, David [Los Alamos National Laboratory; Bent, John [Los Alamos National Laboratory; Chen, Hsing-Bung [Los Alamos National Laboratory; Brandt, Scott [UCSC

    2010-04-05

    Large radio telescopes, cyber-security systems monitoring real-time network traffic, and others have specialized data storage needs: guaranteed capture of an ultra-high-bandwidth data stream, retention of the data long enough to determine what is 'interesting,' retention of interesting data indefinitely, and concurrent read/write access to determine what data is interesting, without interrupting the ongoing capture of incoming data. Mahanaxar addresses this problem. Mahanaxar guarantees streaming real-time data capture at (nearly) the full rate of the raw device, allows concurrent read and write access to the device on a best-effort basis without interrupting the data capture, and retains data as long as possible given the available storage. It has built in mechanisms for reliability and indexing, can scale to meet arbitrary bandwidth requirements, and handles both small and large data elements equally well. Results from our prototype implementation shows that Mahanaxar provides both better guarantees and better performance than traditional file systems.

  3. High-performance parallel processors based on star-coupled wavelength division multiplexing optical interconnects

    Science.gov (United States)

    Deri, Robert J.; DeGroot, Anthony J.; Haigh, Ronald E.

    2002-01-01

    As the performance of individual elements within parallel processing systems increases, increased communication capability between distributed processor and memory elements is required. There is great interest in using fiber optics to improve interconnect communication beyond that attainable using electronic technology. Several groups have considered WDM, star-coupled optical interconnects. The invention uses a fiber optic transceiver to provide low latency, high bandwidth channels for such interconnects using a robust multimode fiber technology. Instruction-level simulation is used to quantify the bandwidth, latency, and concurrency required for such interconnects to scale to 256 nodes, each operating at 1 GFLOPS performance. Performance scales have been shown to .apprxeq.100 GFLOPS for scientific application kernels using a small number of wavelengths (8 to 32), only one wavelength received per node, and achievable optoelectronic bandwidth and latency.

  4. Applied techniques for high bandwidth data transfers across wide area networks

    International Nuclear Information System (INIS)

    Lee, Jason; Gunter, Dan; Tierney, Brian; Allcock, Bill; Bester, Joe; Bresnahan, John; Tuecke, Steve

    2001-01-01

    Large distributed systems such as Computational/Data Grids require large amounts of data to be co-located with the computing facilities for processing. Ensuring that the data is there in time for the computation in today's Internet is a massive problem. From our work developing a scalable distributed network cache, we have gained experience with techniques necessary to achieve high data throughput over high bandwidth Wide Area Networks (WAN). In this paper, we discuss several hardware and software design techniques and issues, and then describe their application to an implementation of an enhanced FTP protocol called GridFTP. We also describe results from two applications using these techniques, which were obtained at the Supercomputing 2000 conference

  5. On Bandwidth Efficient Modulation for High-Data-Rate Wireless LAN Systems

    Directory of Open Access Journals (Sweden)

    Stolpman Victor

    2002-01-01

    Full Text Available We address the problem of high-data-rate orthogonal frequency division multiplexed (OFDM systems under restrictive bandwidth constraints. Based on recent theoretic results, multiple-input multiple-output (MIMO configurations are best suited for this problem. In this paper, we examine several MIMO configurations suitable for high rate transmission. In all scenarios considered, perfect channel state information (CSI is assumed at the receiver. In constrast, availability of CSI at the transmitter is addressed separately. We show that powerful space-time codes can be developed by combining some simple well-known techniques. In fact, we show that for certain configurations, these space-time MIMO configurations are near optimum in terms of outage capacity as compared to previously published codes. Performance evaluation of these techniques is demonstrated within the IEEE 802.11a framework via Monte Carlo simulations.

  6. High-Q Variable Bandwidth Passive Filters for Software Defined Radio

    NARCIS (Netherlands)

    Arkesteijn, V.J.; Klumperink, Eric A.M.; Nauta, Bram

    2001-01-01

    An important aspect of Software Defined Radio is the ability to define the bandwidth of the filter that selects the desired channel. This paper describes a technique for channel filtering, in which two passive filters are combined to obtain a variable bandwidth. Passive filters have the advantage of

  7. High-Q variable bandwidth passive filters for Software Defined Radio

    NARCIS (Netherlands)

    Arkesteijn, V.J.; Klumperink, Eric A.M.; Nauta, Bram

    An important aspect of Software Defined Radio is the ability to define the bandwidth of the filter that selects the desired channel. This paper describes a technique for channel filtering, in which two passive filters are combined to obtain a variable bandwidth. Passive filters have the advantage of

  8. Propagation of 1-THz bandwidth electrical pulses on high Tc superconducting transmission lines

    International Nuclear Information System (INIS)

    Nuss, M.C.; Mankiewich, P.M.; Howard, R.E.; Harvey, T.E.; Brandle, C.D.; Straugh, B.L.; Smith, P.R.

    1989-01-01

    The new high temperature superconductors have triggered enormous interest not only because of the unique physics involved but also because of their technical potentials, such as the promise for propagation of extremely short electrical pulses. Superconducting band caps of --20TH z are predicted assuming BCS theory for the superconductor, making lossless propagation of electrical pulses as short as 50 fs possible. Despite microwave measurements at low frequencies of several gigahertz first studies at higher frequencies by Dykaar et al have shown distortion-free propagation of 100-GHz electrical pulses on YBa 2 Cu 3 O 3 (YBCO) lines for --5-mm propagation distance. Results were also reported for aluminum coplanar lines and a YBCO ground plane. The authors report on the propagation of 1-ps electrical pulses (1-THz bandwidth) on YBCO coplanar transmission lines defined on lanthanum gallate (LaGaO 3 ) as a substrate. On LaGaO 3 , YBCO grows highly oriented as on SrTiO 3 . However, unlike SrTiO 3 , LaGaO 3 has a much lower dielectric constant and small losses in the terahertz frequency range. Electrical pulses of --750-fs duration are generated in a radiation-damaged silicon-on-sapphire photoconductive switch integrated into a 20-μm coplanar stripline with 10-μm spacing and excited with 100-fs optical pulses from a CPM laser. An μ1-THz bandwidth electrical contact is made to the YBCO coplanar stripline defined on LaGaO 3 using a flip-chip geometry. They find that electrical pulses broaden only from 750 fs to 1 ps with little loss in amplitude on traveling through their flip-chip input and propagated electrical pulses are probed by electooptic sampling in two small LiTaO 3 crystals separated by 3 mm

  9. Multi-petascale highly efficient parallel supercomputer

    Science.gov (United States)

    Asaad, Sameh; Bellofatto, Ralph E.; Blocksome, Michael A.; Blumrich, Matthias A.; Boyle, Peter; Brunheroto, Jose R.; Chen, Dong; Cher, Chen-Yong; Chiu, George L.; Christ, Norman; Coteus, Paul W.; Davis, Kristan D.; Dozsa, Gabor J.; Eichenberger, Alexandre E.; Eisley, Noel A.; Ellavsky, Matthew R.; Evans, Kahn C.; Fleischer, Bruce M.; Fox, Thomas W.; Gara, Alan; Giampapa, Mark E.; Gooding, Thomas M.; Gschwind, Michael K.; Gunnels, John A.; Hall, Shawn A.; Haring, Rudolf A.; Heidelberger, Philip; Inglett, Todd A.; Knudson, Brant L.; Kopcsay, Gerard V.; Kumar, Sameer; Mamidala, Amith R.; Marcella, James A.; Megerian, Mark G.; Miller, Douglas R.; Miller, Samuel J.; Muff, Adam J.; Mundy, Michael B.; O'Brien, John K.; O'Brien, Kathryn M.; Ohmacht, Martin; Parker, Jeffrey J.; Poole, Ruth J.; Ratterman, Joseph D.; Salapura, Valentina; Satterfield, David L.; Senger, Robert M.; Steinmacher-Burow, Burkhard; Stockdell, William M.; Stunkel, Craig B.; Sugavanam, Krishnan; Sugawara, Yutaka; Takken, Todd E.; Trager, Barry M.; Van Oosten, James L.; Wait, Charles D.; Walkup, Robert E.; Watson, Alfred T.; Wisniewski, Robert W.; Wu, Peng

    2018-05-15

    A Multi-Petascale Highly Efficient Parallel Supercomputer of 100 petaflop-scale includes node architectures based upon System-On-a-Chip technology, where each processing node comprises a single Application Specific Integrated Circuit (ASIC). The ASIC nodes are interconnected by a five dimensional torus network that optimally maximize the throughput of packet communications between nodes and minimize latency. The network implements collective network and a global asynchronous network that provides global barrier and notification functions. Integrated in the node design include a list-based prefetcher. The memory system implements transaction memory, thread level speculation, and multiversioning cache that improves soft error rate at the same time and supports DMA functionality allowing for parallel processing message-passing.

  10. A 750MHz and a 8GHz High Bandwidth Digital FFT Spectrometer, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The scope of this project is to to develop a wide bandwidth, low power, and compact single board digital Fast Fourier Transform spectrometer (FFTS) optimized for the...

  11. High performance parallel backprojection on FPGA

    Energy Technology Data Exchange (ETDEWEB)

    Pfanner, Florian; Knaup, Michael; Kachelriess, Marc [Erlangen-Nuernberg Univ., Erlangen (Germany). Inst. of Medical Physics (IMP)

    2011-07-01

    Reconstruction of tomographic images, i.e., images from a Computed Tomography scanner, is a very time consuming issue. The most calculation power is needed for the backprojection step. A closer inspection shows that the algorithm for backprojection is easy to parallelize. FPGAs are able to execute many operations in the same time, so a highly parallel algorithm is a requirement for a powerful acceleration. For data flow rate maximization, we realized the backprojection in a pipelined structure with data throughput of one clock cycle. Due the hardware limitations of the FPGA, it is not possible to reconstruct the image as a whole. So it is necessary to split up the image and reconstruct these parts separately. Despite that, a reconstruction of 512 projections into a 5122 image is calculated within 13 ms on a Virtex 5 FPGA. To save hardware resources we use fixed point arithmetic with an accuracy of 23 bit for calculation. A comparison of the result image and an image, calculated with floating point arithmetic on CPU, shows that there are no differences between these images. (orig.)

  12. Effects of bandwidth, compression speed, and gain at high frequencies on preferences for amplified music.

    Science.gov (United States)

    Moore, Brian C J

    2012-09-01

    This article reviews a series of studies on the factors influencing sound quality preferences, mostly for jazz and classical music stimuli. The data were obtained using ratings of individual stimuli or using the method of paired comparisons. For normal-hearing participants, the highest ratings of sound quality were obtained when the reproduction bandwidth was wide (55 to 16000 Hz) and ripples in the frequency response were small (less than ± 5 dB). For hearing-impaired participants listening via a simulated five-channel compression hearing aid with gains set using the CAM2 fitting method, preferences for upper cutoff frequency varied across participants: Some preferred a 7.5- or 10-kHz upper cutoff frequency over a 5-kHz cutoff frequency, and some showed the opposite preference. Preferences for a higher upper cutoff frequency were associated with a shallow high-frequency slope of the audiogram. A subsequent study comparing the CAM2 and NAL-NL2 fitting methods, with gains slightly reduced for participants who were not experienced hearing aid users, showed a consistent preference for CAM2. Since the two methods differ mainly in the gain applied for frequencies above 4 kHz (CAM2 recommending higher gain than NAL-NL2), these results suggest that extending the upper cutoff frequency is beneficial. A system for reducing "overshoot" effects produced by compression gave small but significant benefits for sound quality of a percussion instrument (xylophone). For a high-input level (80 dB SPL), slow compression was preferred over fast compression.

  13. A high performance long-reach passive optical network with a novel excess bandwidth distribution scheme

    Science.gov (United States)

    Chao, I.-Fen; Zhang, Tsung-Min

    2015-06-01

    Long-reach passive optical networks (LR-PONs) have been considered to be promising solutions for future access networks. In this paper, we propose a distributed medium access control (MAC) scheme over an advantageous LR-PON network architecture that reroutes the control information from and back to all ONUs through an (N + 1) × (N + 1) star coupler (SC) deployed near the ONUs, thereby overwhelming the extremely long propagation delay problem in LR-PONs. In the network, the control slot is designed to contain all bandwidth requirements of all ONUs and is in-band time-division-multiplexed with a number of data slots within a cycle. In the proposed MAC scheme, a novel profit-weight-based dynamic bandwidth allocation (P-DBA) scheme is presented. The algorithm is designed to efficiently and fairly distribute the amount of excess bandwidth based on a profit value derived from the excess bandwidth usage of each ONU, which resolves the problems of previously reported DBA schemes that are either unfair or inefficient. The simulation results show that the proposed decentralized algorithms exhibit a nearly three-order-of-magnitude improvement in delay performance compared to the centralized algorithms over LR-PONs. Moreover, the newly proposed P-DBA scheme guarantees low delay performance and fairness even when under attack by the malevolent ONU irrespective of traffic loads and burstiness.

  14. Performance Evaluation of a High Bandwidth Liquid Fuel Modulation Valve for Active Combustion Control

    Science.gov (United States)

    Saus, Joseph R.; DeLaat, John C.; Chang, Clarence T.; Vrnak, Daniel R.

    2012-01-01

    At the NASA Glenn Research Center, a characterization rig was designed and constructed for the purpose of evaluating high bandwidth liquid fuel modulation devices to determine their suitability for active combustion control research. Incorporated into the rig s design are features that approximate conditions similar to those that would be encountered by a candidate device if it were installed on an actual combustion research rig. The characterized dynamic performance measures obtained through testing in the rig are planned to be accurate indicators of expected performance in an actual combustion testing environment. To evaluate how well the characterization rig predicts fuel modulator dynamic performance, characterization rig data was compared with performance data for a fuel modulator candidate when the candidate was in operation during combustion testing. Specifically, the nominal and off-nominal performance data for a magnetostrictive-actuated proportional fuel modulation valve is described. Valve performance data were collected with the characterization rig configured to emulate two different combustion rig fuel feed systems. Fuel mass flows and pressures, fuel feed line lengths, and fuel injector orifice size was approximated in the characterization rig. Valve performance data were also collected with the valve modulating the fuel into the two combustor rigs. Comparison of the predicted and actual valve performance data show that when the valve is operated near its design condition the characterization rig can appropriately predict the installed performance of the valve. Improvements to the characterization rig and accompanying modeling activities are underway to more accurately predict performance, especially for the devices under development to modulate fuel into the much smaller fuel injectors anticipated in future lean-burning low-emissions aircraft engine combustors.

  15. A High Gain-Bandwidth Product Distributed Transimpedance Amplifier IC for High-Speed Optical Transmission Using Low-Cost GaAs Technology.

    OpenAIRE

    Giannini, F.; Limiti, E.; Orengo, G.; Serino, A.; De Dominicis, M.

    2002-01-01

    This paper reports a distributed baseband transimpedance amplifier for optical links up to 10 Gb/s. The amplifier operates as a baseband amplifier with a transimpedance gain of 48 dB Ω and a DC-to-9 GHz bandwidth. Some innovative design techniques to improve gain-bandwidth performance at low and high frequency with an available low-cost GaAs MESFET technology have been developed.

  16. A High-Linearity Low-Noise Amplifier with Variable Bandwidth for Neural Recoding Systems

    Science.gov (United States)

    Yoshida, Takeshi; Sueishi, Katsuya; Iwata, Atsushi; Matsushita, Kojiro; Hirata, Masayuki; Suzuki, Takafumi

    2011-04-01

    This paper describes a low-noise amplifier with multiple adjustable parameters for neural recording applications. An adjustable pseudo-resistor implemented by cascade metal-oxide-silicon field-effect transistors (MOSFETs) is proposed to achieve low-signal distortion and wide variable bandwidth range. The amplifier has been implemented in 0.18 µm standard complementary metal-oxide-semiconductor (CMOS) process and occupies 0.09 mm2 on chip. The amplifier achieved a selectable voltage gain of 28 and 40 dB, variable bandwidth from 0.04 to 2.6 Hz, total harmonic distortion (THD) of 0.2% with 200 mV output swing, input referred noise of 2.5 µVrms over 0.1-100 Hz and 18.7 µW power consumption at a supply voltage of 1.8 V.

  17. Theoretical investigation of injection-locked high modulation bandwidth quantum cascade lasers.

    Science.gov (United States)

    Meng, Bo; Wang, Qi Jie

    2012-01-16

    In this study, we report for the first time to our knowledge theoretical investigation of modulation responses of injection-locked mid-infrared quantum cascade lasers (QCLs) at wavelengths of 4.6 μm and 9 μm, respectively. It is shown through a three-level rate equations model that the direct intensity modulation of QCLs gives the maximum modulation bandwidths of ~7 GHz at 4.6 μm and ~20 GHz at 9 μm. By applying the injection locking scheme, we find that the modulation bandwidths of up to ~30 GHz and ~70 GHz can be achieved for QCLs at 4.6 μm and 9 μm, respectively, with an injection ratio of 5 dB. The result also shows that an ultrawide modulation bandwidth of more than 200 GHz is possible with a 10 dB injection ratio for QCLs at 9 μm. An important characteristic of injection-locked QCLs is the nonexistence of unstable locking region in the locking map, in contrast to their diode laser counterparts. We attribute this to the ultra-short upper laser state lifetimes of QCLs.

  18. Parallel phase model : a programming model for high-end parallel machines with manycores.

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Junfeng (Syracuse University, Syracuse, NY); Wen, Zhaofang; Heroux, Michael Allen; Brightwell, Ronald Brian

    2009-04-01

    This paper presents a parallel programming model, Parallel Phase Model (PPM), for next-generation high-end parallel machines based on a distributed memory architecture consisting of a networked cluster of nodes with a large number of cores on each node. PPM has a unified high-level programming abstraction that facilitates the design and implementation of parallel algorithms to exploit both the parallelism of the many cores and the parallelism at the cluster level. The programming abstraction will be suitable for expressing both fine-grained and coarse-grained parallelism. It includes a few high-level parallel programming language constructs that can be added as an extension to an existing (sequential or parallel) programming language such as C; and the implementation of PPM also includes a light-weight runtime library that runs on top of an existing network communication software layer (e.g. MPI). Design philosophy of PPM and details of the programming abstraction are also presented. Several unstructured applications that inherently require high-volume random fine-grained data accesses have been implemented in PPM with very promising results.

  19. New high voltage parallel plate analyzer

    International Nuclear Information System (INIS)

    Hamada, Y.; Kawasumi, Y.; Masai, K.; Iguchi, H.; Fujisawa, A.; Abe, Y.

    1992-01-01

    A new modification on the parallel plate analyzer for 500 keV heavy ions to eliminate the effect of the intense UV and visible radiations, is successfully conducted. Its principle and results are discussed. (author)

  20. Multi-petascale highly efficient parallel supercomputer

    Science.gov (United States)

    Asaad, Sameh; Bellofatto, Ralph E.; Blocksome, Michael A.; Blumrich, Matthias A.; Boyle, Peter; Brunheroto, Jose R.; Chen, Dong; Cher, Chen -Yong; Chiu, George L.; Christ, Norman; Coteus, Paul W.; Davis, Kristan D.; Dozsa, Gabor J.; Eichenberger, Alexandre E.; Eisley, Noel A.; Ellavsky, Matthew R.; Evans, Kahn C.; Fleischer, Bruce M.; Fox, Thomas W.; Gara, Alan; Giampapa, Mark E.; Gooding, Thomas M.; Gschwind, Michael K.; Gunnels, John A.; Hall, Shawn A.; Haring, Rudolf A.; Heidelberger, Philip; Inglett, Todd A.; Knudson, Brant L.; Kopcsay, Gerard V.; Kumar, Sameer; Mamidala, Amith R.; Marcella, James A.; Megerian, Mark G.; Miller, Douglas R.; Miller, Samuel J.; Muff, Adam J.; Mundy, Michael B.; O'Brien, John K.; O'Brien, Kathryn M.; Ohmacht, Martin; Parker, Jeffrey J.; Poole, Ruth J.; Ratterman, Joseph D.; Salapura, Valentina; Satterfield, David L.; Senger, Robert M.; Smith, Brian; Steinmacher-Burow, Burkhard; Stockdell, William M.; Stunkel, Craig B.; Sugavanam, Krishnan; Sugawara, Yutaka; Takken, Todd E.; Trager, Barry M.; Van Oosten, James L.; Wait, Charles D.; Walkup, Robert E.; Watson, Alfred T.; Wisniewski, Robert W.; Wu, Peng

    2015-07-14

    A Multi-Petascale Highly Efficient Parallel Supercomputer of 100 petaOPS-scale computing, at decreased cost, power and footprint, and that allows for a maximum packaging density of processing nodes from an interconnect point of view. The Supercomputer exploits technological advances in VLSI that enables a computing model where many processors can be integrated into a single Application Specific Integrated Circuit (ASIC). Each ASIC computing node comprises a system-on-chip ASIC utilizing four or more processors integrated into one die, with each having full access to all system resources and enabling adaptive partitioning of the processors to functions such as compute or messaging I/O on an application by application basis, and preferably, enable adaptive partitioning of functions in accordance with various algorithmic phases within an application, or if I/O or other processors are underutilized, then can participate in computation or communication nodes are interconnected by a five dimensional torus network with DMA that optimally maximize the throughput of packet communications between nodes and minimize latency.

  1. The effect of extending high-frequency bandwidth on the acceptable noise level (ANL) of hearing-impaired listeners.

    Science.gov (United States)

    Johnson, Earl; Ricketts, Todd; Hornsby, Benjamin

    2009-01-01

    This study examined the effects of extending high-frequency bandwidth, for both a speech signal and a background noise, on the acceptable signal-to-noise ratio (SNR) of listeners with mild sensorineural hearing loss through utilization of the Acceptable Noise Level (ANL) procedure. In addition to extending high-frequency bandwidth, the effects of reverberation time and background noise type and shape were also examined. The study results showed a significant increase in the mean ANL (i.e. participants requested a better SNR for an acceptable listening situation) when high-frequency bandwidth was extended from 3 to 9 kHz and from 6 to 9 kHz. No change in the ANL of study participants was observed as a result of isolated modification to reverberation time or background noise stimulus. An interaction effect, however, of reverberation time and background noise stimulus was demonstrated. These findings may have implications for future design of hearing aid memory programs for listening to speech in the presence of broadband background noise.

  2. High Performance Parallel Multigrid Algorithms for Unstructured Grids

    Science.gov (United States)

    Frederickson, Paul O.

    1996-01-01

    We describe a high performance parallel multigrid algorithm for a rather general class of unstructured grid problems in two and three dimensions. The algorithm PUMG, for parallel unstructured multigrid, is related in structure to the parallel multigrid algorithm PSMG introduced by McBryan and Frederickson, for they both obtain a higher convergence rate through the use of multiple coarse grids. Another reason for the high convergence rate of PUMG is its smoother, an approximate inverse developed by Baumgardner and Frederickson.

  3. Glass-embedded two-dimensional silicon photonic crystal devices with a broad bandwidth waveguide and a high quality nanocavity.

    Science.gov (United States)

    Jeon, Seung-Woo; Han, Jin-Kyu; Song, Bong-Shik; Noda, Susumu

    2010-08-30

    To enhance the mechanical stability of a two-dimensional photonic crystal slab structure and maintain its excellent performance, we designed a glass-embedded silicon photonic crystal device consisting of a broad bandwidth waveguide and a nanocavity with a high quality (Q) factor, and then fabricated the structure using spin-on glass (SOG). Furthermore, we showed that the refractive index of the SOG could be tuned from 1.37 to 1.57 by varying the curing temperature of the SOG. Finally, we demonstrated a glass-embedded heterostructured cavity with an ultrahigh Q factor of 160,000 by adjusting the refractive index of the SOG.

  4. Adventures in the evolution of a high-bandwidth network for central servers

    International Nuclear Information System (INIS)

    Swartz, K.L.; Cottrell, L.; Dart, M.

    1994-08-01

    In a small network, clients and servers may all be connected to a single Ethernet without significant performance concerns. As the number of clients on a network grows, the necessity of splitting the network into multiple sub-networks, each with a manageable number of clients, becomes clear. Less obvious is what to do with the servers. Group file servers on subnets and multihomed servers offer only partial solutions -- many other types of servers do not lend themselves to a decentralized model, and tend to collect on another, well-connected but overloaded Ethernet. The higher speed of FDDI seems to offer an easy solution, but in practice both expense and interoperability problems render FDDI a poor choice. Ethernet switches appear to permit cheaper and more reliable networking to the servers while providing an aggregate network bandwidth greater than a simple Ethernet. This paper studies the evolution of the server networks at SLAC. Difficulties encountered in the deployment of FDDI are described, as are the tools and techniques used to characterize the traffic patterns on the server network. Performance of Ethernet, FDDI, and switched Ethernet networks is analyzed, as are reliability and maintainability issues for these alternatives. The motivations for re-designing the SLAC general server network to use a switched Ethernet instead of FDDI are described, as are the reasons for choosing FDDI for the farm and firewall networks at SLAC. Guidelines are developed which may help in making this choice for other networks

  5. Technologies for low-bandwidth high-latency unmanned ground vehicle control

    Science.gov (United States)

    Pace, Teresa; Cogan, Ken; Hunt, Lee; Restine, Paul

    2014-05-01

    Automation technology has evolved at a rapid pace in recent years; however, many real-world problems require contextual understanding, problem solving, and other forms of higher-order thinking that extends beyond the capabilities of robots for the foreseeable future. This limits the complexity of automation which can be supplied to modern unmanned ground robots (UGV) and necessitates human-in-the-loop monitoring and control for some portions of missions. In order for the human operator to make decisions and provide tasking during key portions of the mission, existing solutions first derive significant information from a potentially dense reconstruction of the scene utilizing LIDAR, video, and other onboard sensors. A dense reconstruction contains too much data for real-time transmission over a modern wireless data link, so the robot electronics must first condense the scene representation prior to transmission. The control station receives this condensed scene representations and provides visual information to the human operator; the human operator then provides tele-operation commands in real-time to the robot. This paper discusses approaches to dense scene reduction of the data required to transmit to a human-in-the loop as well as the challenges associated with them. In addition, the complex and unstructured nature of real-world environments increases the need for tele-operation. Furthermore, many environments reduce the bandwidth and increase the latency of the link. Ultimately, worsening conditions will cause the tele-operation control process to break down, rendering the robot ineffective. In a worst-case scenario, extreme conditions causing a complete loss-of-communications could result in mission failure and loss of the vehicle.

  6. Teaching RLC Parallel Circuits in High-School Physics Class

    Science.gov (United States)

    Simon, Alpár

    2015-01-01

    This paper will try to give an alternative treatment of the subject "parallel RLC circuits" and "resonance in parallel RLC circuits" from the Physics curricula for the XIth grade from Romanian high-schools, with an emphasis on practical type circuits and their possible applications, and intends to be an aid for both Physics…

  7. A Novel Approach to Reduce the Unicast Bandwidth of an IPTV System in a High-Speed Access Network

    Directory of Open Access Journals (Sweden)

    El Hassane Khabbiza

    2017-01-01

    Full Text Available Channel change time is a critical quality of experience (QOE metric for IP-based video delivery systems such as Internet Protocol Television (IPTV. An interesting channel change acceleration scheme based on peer-assisted delivery was recently proposed, which consists of deploying one FCC server (Fast Channel Change Server in the IP backbone in order to send the unicast stream to the STB (Set-Top Box before sending the normal multicast stream after each channel change. However, deploying such a solution will cause high bandwidth usage in the network because of the huge unicast traffic sent by the FCC server to the STBs. In this paper, we propose a new solution to reduce the bandwidth occupancy of the unicast traffic, by deploying the FCC server capabilities on the user STB. This means that, after each channel change request, the STB will receive the unicast traffic from another STB instead of the central server. By using this method, the unicast traffic will not pass through the IP network; it will be a peer-to-peer communication via the Access Network only. Extensive simulation results are presented to demonstrate the robustness of our new solution.

  8. Design of the corona current measurement sensor with wide bandwidth under dc ultra-high-voltage environment

    International Nuclear Information System (INIS)

    Liu, Yingyi; Yuan, Haiwen; Yang, Qinghua; Cui, Yong

    2011-01-01

    The research in the field of corona discharge, which is one of the key technologies, can help us to realize ultra-high-voltage (UHV) power transmission. This paper proposes a new sampling resistance sensor to measure the dc UHV corona current in a wide band. By designing the structural and distributed parameters of the sensor, the UHV dielectric breakdown performance and the wide-band measuring characteristics of the sensor are satisfied. A high-voltage discharge test shows that the designed sensor can work under a 1200 kV dc environment without the occurrence of corona discharge. A frequency characteristic test shows that the measuring bandwidth of the sensor can be improved from the current 4.5 to 20 MHz. The test results in an actual dc UHV transmission line demonstrate that the sensor can accurately measure the corona current under the dc UHV environment

  9. Hard x-ray monochromator with milli-electron volt bandwidth for high-resolution diffraction studies of diamond crystals

    Energy Technology Data Exchange (ETDEWEB)

    Stoupin, Stanislav; Shvyd' ko, Yuri; Shu Deming; Khachatryan, Ruben; Xiao, Xianghui; DeCarlo, Francesco; Goetze, Kurt; Roberts, Timothy; Roehrig, Christian; Deriy, Alexey [Advanced Photon Source, Argonne National Laboratory, Illinois 60439 (United States)

    2012-02-15

    We report on design and performance of a high-resolution x-ray monochromator with a spectral bandwidth of {Delta}E{sub X}{approx_equal} 1.5 meV, which operates at x-ray energies in the vicinity of the backscattering (Bragg) energy E{sub H} = 13.903 keV of the (008) reflection in diamond. The monochromator is utilized for high-energy-resolution diffraction characterization of diamond crystals as elements of advanced x-ray crystal optics for synchrotrons and x-ray free-electron lasers. The monochromator and the related controls are made portable such that they can be installed and operated at any appropriate synchrotron beamline equipped with a pre-monochromator.

  10. Development of Industrial High-Speed Transfer Parallel Robot

    International Nuclear Information System (INIS)

    Kim, Byung In; Kyung, Jin Ho; Do, Hyun Min; Jo, Sang Hyun

    2013-01-01

    Parallel robots used in industry require high stiffness or high speed because of their structural characteristics. Nowadays, the importance of rapid transportation has increased in the distribution industry. In this light, an industrial parallel robot has been developed for high-speed transfer. The developed parallel robot can handle a maximum payload of 3 kg. For a payload of 0.1 kg, the trajectory cycle time is 0.3 s (come and go), and the maximum velocity is 4.5 m/s (pick amp, place work, adept cycle). In this motion, its maximum acceleration is very high and reaches approximately 13g. In this paper, the design, analysis, and performance test results of the developed parallel robot system are introduced

  11. Implementation of a high performance parallel finite element micromagnetics package

    International Nuclear Information System (INIS)

    Scholz, W.; Suess, D.; Dittrich, R.; Schrefl, T.; Tsiantos, V.; Forster, H.; Fidler, J.

    2004-01-01

    A new high performance scalable parallel finite element micromagnetics package has been implemented. It includes solvers for static energy minimization, time integration of the Landau-Lifshitz-Gilbert equation, and the nudged elastic band method

  12. The ongoing investigation of high performance parallel computing in HEP

    CERN Document Server

    Peach, Kenneth J; Böck, R K; Dobinson, Robert W; Hansroul, M; Norton, Alan Robert; Willers, Ian Malcolm; Baud, J P; Carminati, F; Gagliardi, F; McIntosh, E; Metcalf, M; Robertson, L; CERN. Geneva. Detector Research and Development Committee

    1993-01-01

    Past and current exploitation of parallel computing in High Energy Physics is summarized and a list of R & D projects in this area is presented. The applicability of new parallel hardware and software to physics problems is investigated, in the light of the requirements for computing power of LHC experiments and the current trends in the computer industry. Four main themes are discussed (possibilities for a finer grain of parallelism; fine-grain communication mechanism; usable parallel programming environment; different programming models and architectures, using standard commercial products). Parallel computing technology is potentially of interest for offline and vital for real time applications in LHC. A substantial investment in applications development and evaluation of state of the art hardware and software products is needed. A solid development environment is required at an early stage, before mainline LHC program development begins.

  13. A high-speed linear algebra library with automatic parallelism

    Science.gov (United States)

    Boucher, Michael L.

    1994-01-01

    Parallel or distributed processing is key to getting highest performance workstations. However, designing and implementing efficient parallel algorithms is difficult and error-prone. It is even more difficult to write code that is both portable to and efficient on many different computers. Finally, it is harder still to satisfy the above requirements and include the reliability and ease of use required of commercial software intended for use in a production environment. As a result, the application of parallel processing technology to commercial software has been extremely small even though there are numerous computationally demanding programs that would significantly benefit from application of parallel processing. This paper describes DSSLIB, which is a library of subroutines that perform many of the time-consuming computations in engineering and scientific software. DSSLIB combines the high efficiency and speed of parallel computation with a serial programming model that eliminates many undesirable side-effects of typical parallel code. The result is a simple way to incorporate the power of parallel processing into commercial software without compromising maintainability, reliability, or ease of use. This gives significant advantages over less powerful non-parallel entries in the market.

  14. Designing a High Performance Parallel Personal Cluster

    OpenAIRE

    Kapanova, K. G.; Sellier, J. M.

    2016-01-01

    Today, many scientific and engineering areas require high performance computing to perform computationally intensive experiments. For example, many advances in transport phenomena, thermodynamics, material properties, computational chemistry and physics are possible only because of the availability of such large scale computing infrastructures. Yet many challenges are still open. The cost of energy consumption, cooling, competition for resources have been some of the reasons why the scientifi...

  15. High-energy physics software parallelization using database techniques

    International Nuclear Information System (INIS)

    Argante, E.; Van der Stok, P.D.V.; Willers, I.

    1997-01-01

    A programming model for software parallelization, called CoCa, is introduced that copes with problems caused by typical features of high-energy physics software. By basing CoCa on the database transaction paradigm, the complexity induced by the parallelization is for a large part transparent to the programmer, resulting in a higher level of abstraction than the native message passing software. CoCa is implemented on a Meiko CS-2 and on a SUN SPARCcenter 2000 parallel computer. On the CS-2, the performance is comparable with the performance of native PVM and MPI. (orig.)

  16. Cosmic Microwave Background Polarization Detector with High Efficiency, Broad Bandwidth, and Highly Symmetric Coupling to Transition Edge Sensor Bolometers

    Science.gov (United States)

    Wollack, E.; Cao, N.; Chuss, D.; Denis, K.; Hsieh, W.-T.; Moseley, S. Harvey; Schneider, G.; Stevenson, T.; Travers, D.; U-yen, K.

    2008-01-01

    Four probe antennas transfer signals from waveguide to microstrip lines. The probes not only provide broadband impedance matching, but also thermally isolate waveguide and detector. In addition, we developed a new photonic waveguide choke joint design, with four-fold symmetry, to suppress power leakage at the interface. We have developed facilities to test superconducting circuit elements using a cryogenic microwave probe station, and more complete systems in waveguide. We used the ring resonator shown below to measure a dielectric loss tangent 99% coupling efficiency over 30% fractional bandwidth.

  17. The FORCE: A highly portable parallel programming language

    Science.gov (United States)

    Jordan, Harry F.; Benten, Muhammad S.; Alaghband, Gita; Jakob, Ruediger

    1989-01-01

    Here, it is explained why the FORCE parallel programming language is easily portable among six different shared-memory microprocessors, and how a two-level macro preprocessor makes it possible to hide low level machine dependencies and to build machine-independent high level constructs on top of them. These FORCE constructs make it possible to write portable parallel programs largely independent of the number of processes and the specific shared memory multiprocessor executing them.

  18. The FORCE - A highly portable parallel programming language

    Science.gov (United States)

    Jordan, Harry F.; Benten, Muhammad S.; Alaghband, Gita; Jakob, Ruediger

    1989-01-01

    This paper explains why the FORCE parallel programming language is easily portable among six different shared-memory multiprocessors, and how a two-level macro preprocessor makes it possible to hide low-level machine dependencies and to build machine-independent high-level constructs on top of them. These FORCE constructs make it possible to write portable parallel programs largely independent of the number of processes and the specific shared-memory multiprocessor executing them.

  19. Effect of Feed Substrate Thickness on the Bandwidth and Radiation Characteristics of an Aperture-Coupled Microstrip Antenna with a High Permittivity Feed Substrate

    Directory of Open Access Journals (Sweden)

    Jae-Hyun Kim

    2018-04-01

    Full Text Available The impedance bandwidth and radiation characteristics of an aperture-coupled microstrip line-fed patch antenna (ACMPA with a high permittivity (ɛr = 10 feed substrate suitable for integration with a monolithic microwave integrated circuit (MMIC are investigated for various feed substrate thicknesses through an experiment and computer simulation. The impedance bandwidth of an ACMPA with a high permittivity feed substrate increases as the feed substrate thickness decreases. Furthermore, the front-to-back ratio of an ACMPA with a high permittivity feed substrate increases and the cross-polarization level decreases as the feed substrate thickness decreases. As the impedance bandwidth of an ACMPA with a high permittivity feed substrate increases and its radiation characteristics improve as the feed substrate thickness decreases, the ACMPA configuration becomes suitable for integration with an MMIC.

  20. A parallel solution for high resolution histological image analysis.

    Science.gov (United States)

    Bueno, G; González, R; Déniz, O; García-Rojo, M; González-García, J; Fernández-Carrobles, M M; Vállez, N; Salido, J

    2012-10-01

    This paper describes a general methodology for developing parallel image processing algorithms based on message passing for high resolution images (on the order of several Gigabytes). These algorithms have been applied to histological images and must be executed on massively parallel processing architectures. Advances in new technologies for complete slide digitalization in pathology have been combined with developments in biomedical informatics. However, the efficient use of these digital slide systems is still a challenge. The image processing that these slides are subject to is still limited both in terms of data processed and processing methods. The work presented here focuses on the need to design and develop parallel image processing tools capable of obtaining and analyzing the entire gamut of information included in digital slides. Tools have been developed to assist pathologists in image analysis and diagnosis, and they cover low and high-level image processing methods applied to histological images. Code portability, reusability and scalability have been tested by using the following parallel computing architectures: distributed memory with massive parallel processors and two networks, INFINIBAND and Myrinet, composed of 17 and 1024 nodes respectively. The parallel framework proposed is flexible, high performance solution and it shows that the efficient processing of digital microscopic images is possible and may offer important benefits to pathology laboratories. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  1. High Bandwidth Zero Voltage Injection Method for Sensorless Control of PMSM

    DEFF Research Database (Denmark)

    Ge, Xie; Lu, Kaiyuan; Kumar, Dwivedi Sanjeet

    2014-01-01

    High frequency signal injection is widely used in PMSM sensorless control system for low speed operations. The conventional voltage injection method often needs filters to obtain particular harmonic component in order to estimate the rotor position; or it requires several voltage pulses to be inj......High frequency signal injection is widely used in PMSM sensorless control system for low speed operations. The conventional voltage injection method often needs filters to obtain particular harmonic component in order to estimate the rotor position; or it requires several voltage pulses...... in a fast current regulation performance. Injection of zero voltage also minimizes the inverter voltage error effects caused by the dead-time....

  2. High Efficiency EBCOT with Parallel Coding Architecture for JPEG2000

    Directory of Open Access Journals (Sweden)

    Chiang Jen-Shiun

    2006-01-01

    Full Text Available This work presents a parallel context-modeling coding architecture and a matching arithmetic coder (MQ-coder for the embedded block coding (EBCOT unit of the JPEG2000 encoder. Tier-1 of the EBCOT consumes most of the computation time in a JPEG2000 encoding system. The proposed parallel architecture can increase the throughput rate of the context modeling. To match the high throughput rate of the parallel context-modeling architecture, an efficient pipelined architecture for context-based adaptive arithmetic encoder is proposed. This encoder of JPEG2000 can work at 180 MHz to encode one symbol each cycle. Compared with the previous context-modeling architectures, our parallel architectures can improve the throughput rate up to 25%.

  3. High temporal resolution functional MRI using parallel echo volumar imaging

    International Nuclear Information System (INIS)

    Rabrait, C.; Ciuciu, P.; Ribes, A.; Poupon, C.; Dehaine-Lambertz, G.; LeBihan, D.; Lethimonnier, F.; Le Roux, P.; Dehaine-Lambertz, G.

    2008-01-01

    Purpose: To combine parallel imaging with 3D single-shot acquisition (echo volumar imaging, EVI) in order to acquire high temporal resolution volumar functional MRI (fMRI) data. Materials and Methods: An improved EVI sequence was associated with parallel acquisition and field of view reduction in order to acquire a large brain volume in 200 msec. Temporal stability and functional sensitivity were increased through optimization of all imaging parameters and Tikhonov regularization of parallel reconstruction. Two human volunteers were scanned with parallel EVI in a 1.5 T whole-body MR system, while submitted to a slow event-related auditory paradigm. Results: Thanks to parallel acquisition, the EVI volumes display a low level of geometric distortions and signal losses. After removal of low-frequency drifts and physiological artifacts,activations were detected in the temporal lobes of both volunteers and voxel-wise hemodynamic response functions (HRF) could be computed. On these HRF different habituation behaviors in response to sentence repetition could be identified. Conclusion: This work demonstrates the feasibility of high temporal resolution 3D fMRI with parallel EVI. Combined with advanced estimation tools,this acquisition method should prove useful to measure neural activity timing differences or study the nonlinearities and non-stationarities of the BOLD response. (authors)

  4. Radiation-hard/high-speed parallel optical links

    International Nuclear Information System (INIS)

    Gan, K.K.; Buchholz, P.; Kagan, H.P.; Kass, R.D.; Moore, J.; Smith, D.S.; Wiese, A.; Ziolkowski, M.

    2014-01-01

    We have designed an ASIC for use in a parallel optical engine for a new layer of the ATLAS pixel detector in the initial phase of the LHC luminosity upgrade. The ASIC is a 12-channel VCSEL (Vertical Cavity Surface Emitting Laser) array driver capable of operating up to 5 Gb/s per channel. The ASIC is designed using a 130 nm CMOS process to enhance the radiation-hardness. A scheme for redundancy has also been implemented to allow bypassing of a broken VCSEL. The ASIC also contains a power-on reset circuit that sets the ASIC to a default configuration with no signal steering. In addition, the bias and modulation currents of the individual channels are programmable. The performance of the first prototype ASIC up to 5 Gb/s is satisfactory. Furthermore, we are able to program the bias and modulation currents and to bypass a broken VCSEL channel. We are currently upgrading our design to allow operation at 10 Gb/s per channel yielding an aggregated bandwidth of 120 Gb/s. Some preliminary results of the design will be presented

  5. Level-1 Data Driver Card - A high bandwidth radiation tolerant aggregator board for detectors

    CERN Document Server

    Gkountoumis, Panagiotis; The ATLAS collaboration

    2017-01-01

    The Level-1 Data Driver Card (L1DDC) was designed for the needs of the future upgrades of the innermost stations of the ATLAS end-cap muon spectrometer. The L1DDC is a high speed aggregator board capable of communicating with multiple front-end electronic boards. It collects the Level-1 data along with monitoring data and transmits them to a network interface through bidirectional and/or unidirectional fiber links at 4.8 Gbps each. In addition, the L1DDC board distributes trigger, time and configuration data coming from the network interface to the front-end boards. The L1DDC is fully compatible with the Phase II upgrade where the trigger rate is expected to reach the 1 MHz. Three different types of L1DDC boards will be fabricated handling up to 10.080 Gbps of user data. It consist of custom made radiation tolerant ASICs: the GigaBit Transceiver (GBTx), the FEAST DC-DC converter, the Slow Control Adapter (SCA), and the Versatile Tranceivers (VTRX) and transmitters (VTTX). The overall scheme of the data acquis...

  6. High bandwidth pixel detector modules for the ATLAS Insertable B-Layer

    International Nuclear Information System (INIS)

    Backhaus, Malte

    2014-01-01

    The investigation of the nature of the recently discovered electro-weak symmetry breaking mechanism of the standard model of particle physics as well as the search for physics beyond the standard model with the LHC require to collect even more data. To achieve this goal, the luminosity of the LHC will be increased in two steps. The increased luminosity results in serious challenges for the inner tracking systems of the experiments at the LHC. The ATLAS pixel detector will also be upgraded in a two stage program. During the shutdown in 2013 and 2014 a fourth hybrid pixel detector layer, the socalled Insertable B-Layer (IBL) is inserted inside the existing pixel detector. This thesis focuses on the characterization, performance measurement, and production quality assurance of the central sensitive elements of the IBL, the modules. This includes a full characterization of the readout chip (FE-I4) and of the assembled modules. A completely new inner tracking system is mandatory in ATLAS after the second luminosity increase in the shutdown of 2022 and 2023. The final chapter of this thesis introduces a new module concept that uses an industrial high voltage CMOS technology as sensor layer, which is capacitively coupled to the FE-I4 readout chip.

  7. LEVEL-1 DATA DRIVER CARD - A high bandwidth radiation tolerant aggregator board for detectors

    CERN Document Server

    Gkountoumis, Panagiotis; The ATLAS collaboration

    2018-01-01

    The Level-1 Data Driver Card (L1DDC) was designed for the needs of the future upgrades of the innermost stations of the ATLAS end-cap muon spectrometer. The detectors located at the muon Small Wheels will be replaced by a set of precision tracking and trigger detectors, the resistive Micromegas (MM) and the small-strip Thin Gap Chambers (sTGC). After the upgrade, the number of interactions per bunch-crossing will be increased up to 140, resulting in a dramatically large amount of produced data. The high number of electronic channels (about two million for the MM and about 300k for the sTGC) along with a harsh environment (radiation dose up to 1700Gy (inner radius) and a magnetic field up to 0:4T in the end cap region) led to the development of new radiation tolerant electronics and a scalable readout scheme able to handle the new data rates. In addition, correction mechanisms for Single Event Upsets (SEU) and communication errors must be implemented to assure the integrity of the transmitted data. The L1DDC i...

  8. High spatial resolution CT image reconstruction using parallel computing

    International Nuclear Information System (INIS)

    Yin Yin; Liu Li; Sun Gongxing

    2003-01-01

    Using the PC cluster system with 16 dual CPU nodes, we accelerate the FBP and OR-OSEM reconstruction of high spatial resolution image (2048 x 2048). Based on the number of projections, we rewrite the reconstruction algorithms into parallel format and dispatch the tasks to each CPU. By parallel computing, the speedup factor is roughly equal to the number of CPUs, which can be up to about 25 times when 25 CPUs used. This technique is very suitable for real-time high spatial resolution CT image reconstruction. (authors)

  9. Parallel Computing:. Some Activities in High Energy Physics

    Science.gov (United States)

    Willers, Ian

    This paper examines some activities in High Energy Physics that utilise parallel computing. The topic includes all computing from the proposed SIMD front end detectors, the farming applications, high-powered RISC processors and the large machines in the computer centers. We start by looking at the motivation behind using parallelism for general purpose computing. The developments around farming are then described from its simplest form to the more complex system in Fermilab. Finally, there is a list of some developments that are happening close to the experiments.

  10. Pushing the Envelope: Ship to Shore Events and High-Bandwidth Telepresence Engages Scientists and the Public

    Science.gov (United States)

    Cooper, S. K.; Coleman, D. F.; Fisher, A. T.; Livelybrooks, D.; Mulder, G.

    2013-12-01

    Since 2009, the drillship JOIDES Resolution has engaged in an extensive program of live ship-to-shore events during its two-month scientific expeditions using a range of software applications and formats. The University of Rhode Island's Inner Space Center has utilized a high bandwidth 'telepresence' from ships such as the Ocean Exploration Trust's E/V Nautilus and the NOAA Ship Okeanos Explorer, to bring live feeds from underwater exploration vehicles directly into museums, aquaria, science centers, boys and girls clubs, and K-16 classrooms. Both of these strategies have employed close partnerships between scientists and educators to bring cutting edge research and the excitement of exploration and discovery directly to the public in close to real time, but telepresence provides unique opportunities. Participants have been able to experience, live, launches of remotely operated vehicle systems including Jason/Medea on R/V Atlantis and Hercules/Argus on Nautilus, see scientific samples come up on deck for the very first time, observe previously-undiscovered shipwrecks at the same time as those on ship, and watch amazing deep sea creatures swim past deep water cameras. There are many benefits from high-bandwidth telepresence, including improved quality of images, video, and sound; the ability to move large data sets and files between ship and shore, allowing collaboration among individuals who are not on the ship; the ability to stage spontaneous "web events" among scientific, educational, and technical personnel at essentially any time; and more intensive interactions through use of social media, such as blogging, posting of multimedia products, and frequent question/answer sessions. These telepresence-enhanced activities assist the public in understanding the significance and excitement of these discoveries, the challenges of working in the deep sea, and the true nature of scientific processes. These interactions have significant impacts on their audiences, and

  11. Event parallelism: Distributed memory parallel computing for high energy physics experiments

    International Nuclear Information System (INIS)

    Nash, T.

    1989-05-01

    This paper describes the present and expected future development of distributed memory parallel computers for high energy physics experiments. It covers the use of event parallel microprocessor farms, particularly at Fermilab, including both ACP multiprocessors and farms of MicroVAXES. These systems have proven very cost effective in the past. A case is made for moving to the more open environment of UNIX and RISC processors. The 2nd Generation ACP Multiprocessor System, which is based on powerful RISC systems, is described. Given the promise of still more extraordinary increases in processor performance, a new emphasis on point to point, rather than bussed, communication will be required. Developments in this direction are described. 6 figs

  12. Event parallelism: Distributed memory parallel computing for high energy physics experiments

    International Nuclear Information System (INIS)

    Nash, T.

    1989-01-01

    This paper describes the present and expected future development of distributed memory parallel computers for high energy physics experiments. It covers the use of event parallel microprocessor farms, particularly at Fermilab, including both ACP multiprocessors and farms of MicroVAXES. These systems have proven very cost effective in the past. A case is made for moving to the more open environment of UNIX and RISC processors. The 2nd Generation ACP Multiprocessor System, which is based on powerful RISC systems, is described. Given the promise of still more extraordinary increases in processor performance, a new emphasis on point to point, rather than bussed, communication will be required. Developments in this direction are described. (orig.)

  13. Event parallelism: Distributed memory parallel computing for high energy physics experiments

    Science.gov (United States)

    Nash, Thomas

    1989-12-01

    This paper describes the present and expected future development of distributed memory parallel computers for high energy physics experiments. It covers the use of event parallel microprocessor farms, particularly at Fermilab, including both ACP multiprocessors and farms of MicroVAXES. These systems have proven very cost effective in the past. A case is made for moving to the more open environment of UNIX and RISC processors. The 2nd Generation ACP Multiprocessor System, which is based on powerful RISC system, is described. Given the promise of still more extraordinary increases in processor performance, a new emphasis on point to point, rather than bussed, communication will be required. Developments in this direction are described.

  14. A parallelization study of the general purpose Monte Carlo code MCNP4 on a distributed memory highly parallel computer

    International Nuclear Information System (INIS)

    Yamazaki, Takao; Fujisaki, Masahide; Okuda, Motoi; Takano, Makoto; Masukawa, Fumihiro; Naito, Yoshitaka

    1993-01-01

    The general purpose Monte Carlo code MCNP4 has been implemented on the Fujitsu AP1000 distributed memory highly parallel computer. Parallelization techniques developed and studied are reported. A shielding analysis function of the MCNP4 code is parallelized in this study. A technique to map a history to each processor dynamically and to map control process to a certain processor was applied. The efficiency of parallelized code is up to 80% for a typical practical problem with 512 processors. These results demonstrate the advantages of a highly parallel computer to the conventional computers in the field of shielding analysis by Monte Carlo method. (orig.)

  15. Parallel computing for event reconstruction in high-energy physics

    International Nuclear Information System (INIS)

    Wolbers, S.

    1993-01-01

    Parallel computing has been recognized as a solution to large computing problems. In High Energy Physics offline event reconstruction of detector data is a very large computing problem that has been solved with parallel computing techniques. A review of the parallel programming package CPS (Cooperative Processes Software) developed and used at Fermilab for offline reconstruction of Terabytes of data requiring the delivery of hundreds of Vax-Years per experiment is given. The Fermilab UNIX farms, consisting of 180 Silicon Graphics workstations and 144 IBM RS6000 workstations, are used to provide the computing power for the experiments. Fermilab has had a long history of providing production parallel computing starting with the ACP (Advanced Computer Project) Farms in 1986. The Fermilab UNIX Farms have been in production for over 2 years with 24 hour/day service to experimental user groups. Additional tools for management, control and monitoring these large systems will be described. Possible future directions for parallel computing in High Energy Physics will be given

  16. Parallel Libraries to support High-Level Programming

    DEFF Research Database (Denmark)

    Larsen, Morten Nørgaard

    and the Microsoft .NET iv framework. Normally, one would not directly think of the .NET framework when talking scientific applications, but Microsoft has in the last couple of versions of .NET introduce a number of tools for writing parallel and high performance code. The first section examines how programmers can...

  17. Remote parallel rendering for high-resolution tiled display walls

    KAUST Repository

    Nachbaur, Daniel

    2014-11-01

    © 2014 IEEE. We present a complete, robust and simple to use hardware and software stack delivering remote parallel rendering of complex geometrical and volumetric models to high resolution tiled display walls in a production environment. We describe the setup and configuration, present preliminary benchmarks showing interactive framerates, and describe our contributions for a seamless integration of all the software components.

  18. Remote parallel rendering for high-resolution tiled display walls

    KAUST Repository

    Nachbaur, Daniel; Dumusc, Raphael; Bilgili, Ahmet; Hernando, Juan; Eilemann, Stefan

    2014-01-01

    © 2014 IEEE. We present a complete, robust and simple to use hardware and software stack delivering remote parallel rendering of complex geometrical and volumetric models to high resolution tiled display walls in a production environment. We describe the setup and configuration, present preliminary benchmarks showing interactive framerates, and describe our contributions for a seamless integration of all the software components.

  19. High-Efficient Parallel CAVLC Encoders on Heterogeneous Multicore Architectures

    Directory of Open Access Journals (Sweden)

    H. Y. Su

    2012-04-01

    Full Text Available This article presents two high-efficient parallel realizations of the context-based adaptive variable length coding (CAVLC based on heterogeneous multicore processors. By optimizing the architecture of the CAVLC encoder, three kinds of dependences are eliminated or weaken, including the context-based data dependence, the memory accessing dependence and the control dependence. The CAVLC pipeline is divided into three stages: two scans, coding, and lag packing, and be implemented on two typical heterogeneous multicore architectures. One is a block-based SIMD parallel CAVLC encoder on multicore stream processor STORM. The other is a component-oriented SIMT parallel encoder on massively parallel architecture GPU. Both of them exploited rich data-level parallelism. Experiments results show that compared with the CPU version, more than 70 times of speedup can be obtained for STORM and over 50 times for GPU. The implementation of encoder on STORM can make a real-time processing for 1080p @30fps and GPU-based version can satisfy the requirements for 720p real-time encoding. The throughput of the presented CAVLC encoders is more than 10 times higher than that of published software encoders on DSP and multicore platforms.

  20. VisIO: enabling interactive visualization of ultra-scale, time-series data via high-bandwidth distributed I/O systems

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, Christopher J [Los Alamos National Laboratory; Ahrens, James P [Los Alamos National Laboratory; Wang, Jun [UCF

    2010-10-15

    Petascale simulations compute at resolutions ranging into billions of cells and write terabytes of data for visualization and analysis. Interactive visuaUzation of this time series is a desired step before starting a new run. The I/O subsystem and associated network often are a significant impediment to interactive visualization of time-varying data; as they are not configured or provisioned to provide necessary I/O read rates. In this paper, we propose a new I/O library for visualization applications: VisIO. Visualization applications commonly use N-to-N reads within their parallel enabled readers which provides an incentive for a shared-nothing approach to I/O, similar to other data-intensive approaches such as Hadoop. However, unlike other data-intensive applications, visualization requires: (1) interactive performance for large data volumes, (2) compatibility with MPI and POSIX file system semantics for compatibility with existing infrastructure, and (3) use of existing file formats and their stipulated data partitioning rules. VisIO, provides a mechanism for using a non-POSIX distributed file system to provide linear scaling of 110 bandwidth. In addition, we introduce a novel scheduling algorithm that helps to co-locate visualization processes on nodes with the requested data. Testing using VisIO integrated into Para View was conducted using the Hadoop Distributed File System (HDFS) on TACC's Longhorn cluster. A representative dataset, VPIC, across 128 nodes showed a 64.4% read performance improvement compared to the provided Lustre installation. Also tested, was a dataset representing a global ocean salinity simulation that showed a 51.4% improvement in read performance over Lustre when using our VisIO system. VisIO, provides powerful high-performance I/O services to visualization applications, allowing for interactive performance with ultra-scale, time-series data.

  1. Integrated computer network high-speed parallel interface

    International Nuclear Information System (INIS)

    Frank, R.B.

    1979-03-01

    As the number and variety of computers within Los Alamos Scientific Laboratory's Central Computer Facility grows, the need for a standard, high-speed intercomputer interface has become more apparent. This report details the development of a High-Speed Parallel Interface from conceptual through implementation stages to meet current and future needs for large-scle network computing within the Integrated Computer Network. 4 figures

  2. Application of a modified complementary filtering technique for increased aircraft control system frequency bandwidth in high vibration environment

    Science.gov (United States)

    Garren, J. F., Jr.; Niessen, F. R.; Abbott, T. S.; Yenni, K. R.

    1977-01-01

    A modified complementary filtering technique for estimating aircraft roll rate was developed and flown in a research helicopter to determine whether higher gains could be achieved. Use of this technique did, in fact, permit a substantial increase in system frequency bandwidth because, in comparison with first-order filtering, it reduced both noise amplification and control limit-cycle tendencies.

  3. Data driven parallelism in experimental high energy physics applications

    International Nuclear Information System (INIS)

    Pohl, M.

    1987-01-01

    I present global design principles for the implementation of high energy physics data analysis code on sequential and parallel processors with mixed shared and local memory. Potential parallelism in the structure of high energy physics tasks is identified with granularity varying from a few times 10 8 instructions all the way down to a few times 10 4 instructions. It follows the hierarchical structure of detector and data acquisition systems. To take advantage of this - yet preserving the necessary portability of the code - I propose a computational model with purely data driven concurrency in Single Program Multiple Data (SPMD) mode. The task granularity is defined by varying the granularity of the central data structure manipulated. Concurrent processes coordiate themselves asynchroneously using simple lock constructs on parts of the data structure. Load balancing among processes occurs naturally. The scheme allows to map the internal layout of the data structure closely onto the layout of local and shared memory in a parallel architecture. It thus allows to optimize the application with respect to synchronization as well as data transport overheads. I present a coarse top level design for a portable implementation of this scheme on sequential machines, multiprocessor mainframes (e.g. IBM 3090), tightly coupled multiprocessors (e.g. RP-3) and loosely coupled processor arrays (e.g. LCAP, Emulating Processor Farms). (orig.)

  4. Highly scalable parallel processing of extracellular recordings of Multielectrode Arrays.

    Science.gov (United States)

    Gehring, Tiago V; Vasilaki, Eleni; Giugliano, Michele

    2015-01-01

    Technological advances of Multielectrode Arrays (MEAs) used for multisite, parallel electrophysiological recordings, lead to an ever increasing amount of raw data being generated. Arrays with hundreds up to a few thousands of electrodes are slowly seeing widespread use and the expectation is that more sophisticated arrays will become available in the near future. In order to process the large data volumes resulting from MEA recordings there is a pressing need for new software tools able to process many data channels in parallel. Here we present a new tool for processing MEA data recordings that makes use of new programming paradigms and recent technology developments to unleash the power of modern highly parallel hardware, such as multi-core CPUs with vector instruction sets or GPGPUs. Our tool builds on and complements existing MEA data analysis packages. It shows high scalability and can be used to speed up some performance critical pre-processing steps such as data filtering and spike detection, helping to make the analysis of larger data sets tractable.

  5. Data driven parallelism in experimental high energy physics applications

    Science.gov (United States)

    Pohl, Martin

    1987-08-01

    I present global design principles for the implementation of High Energy Physics data analysis code on sequential and parallel processors with mixed shared and local memory. Potential parallelism in the structure of High Energy Physics tasks is identified with granularity varying from a few times 10 8 instructions all the way down to a few times 10 4 instructions. It follows the hierarchical structure of detector and data acquisition systems. To take advantage of this - yet preserving the necessary portability of the code - I propose a computational model with purely data driven concurrency in Single Program Multiple Data (SPMD) mode. The Task granularity is defined by varying the granularity of the central data structure manipulated. Concurrent processes coordinate themselves asynchroneously using simple lock constructs on parts of the data structure. Load balancing among processes occurs naturally. The scheme allows to map the internal layout of the data structure closely onto the layout of local and shared memory in a parallel architecture. It thus allows to optimize the application with respect to synchronization as well as data transport overheads. I present a coarse top level design for a portable implementation of this scheme on sequential machines, multiprocessor mainframes (e.g. IBM 3090), tightly coupled multiprocessors (e.g. RP-3) and loosely coupled processor arrays (e.g. LCAP, Emulating Processor Farms).

  6. Vortex structure behind highly heated two cylinders in parallel arrangements

    International Nuclear Information System (INIS)

    Kurita, Eiichirou; Yahagi, Yuji

    2008-01-01

    Vortex structures behind twin, highly heated cylinders in parallel arrangements have been investigated experimentally. The experiments were conducted under the following conditions: cylinder diameter, D=4 mm; mean flow velocity, U ∞ =1.0 m/s; Reynolds number, Re=250; cylinder clearance, S/D=0.5 - 1.4; and cylinder heat flux, q=0 - 72.6 kW/m 2 . For S/D > 1.2, the Karman vortex street is formed alternately behind each cylinder divided on the slit flow. The slit flow velocity increases with a decrease in S/D and decreases with increasing heat flux. For S/D 2 ). As a result, the increased local kinematic viscosity and S/D play a key role for the vortex structure and formation behind arrangements of two parallel cylinders. (author)

  7. Particle simulation on a distributed memory highly parallel processor

    International Nuclear Information System (INIS)

    Sato, Hiroyuki; Ikesaka, Morio

    1990-01-01

    This paper describes parallel molecular dynamics simulation of atoms governed by local force interaction. The space in the model is divided into cubic subspaces and mapped to the processor array of the CAP-256, a distributed memory, highly parallel processor developed at Fujitsu Labs. We developed a new technique to avoid redundant calculation of forces between atoms in different processors. Experiments showed the communication overhead was less than 5%, and the idle time due to load imbalance was less than 11% for two model problems which contain 11,532 and 46,128 argon atoms. From the software simulation, the CAP-II which is under development is estimated to be about 45 times faster than CAP-256 and will be able to run the same problem about 40 times faster than Fujitsu's M-380 mainframe when 256 processors are used. (author)

  8. Imaging RF Phased Array Receivers using Optically-Coherent Up-conversion for High Beam-Bandwidth Processing

    Science.gov (United States)

    2017-03-01

    It does so by using an optical lens to perform an inverse spatial Fourier Transform on the up-converted RF signals, thereby rendering a real-time... simultaneous beams or other engineered beam patterns. There are two general approaches to array-based beam forming: digital and analog. In digital beam...of significantly limiting the number of beams that can be formed simultaneously and narrowing the operational bandwidth. An alternate approach that

  9. High-bandwidth scanned-wavelength-modulation spectroscopy sensors for temperature and H2O in a rotating detonation engine

    International Nuclear Information System (INIS)

    Goldenstein, Christopher S; Almodóvar, Christopher A; Jeffries, Jay B; Hanson, Ronald K; Brophy, Christopher M

    2014-01-01

    The design and use of two-color tunable diode laser (TDL) absorption sensors for measurements of temperature and H 2 O in a rotating detonation engine (RDE) are presented. Both sensors used first-harmonic-normalized scanned-wavelength-modulation spectroscopy with second-harmonic detection (scanned-WMS-2f/1f) to account for non-absorbing transmission losses and emission encountered in the harsh combustion environment. One sensor used two near-infrared (NIR) TDLs near 1391.7 nm and 1469.3 nm that were modulated at 225 kHz and 285 kHz, respectively, and sinusoidally scanned across the peak of their respective H 2 O absorption transitions to provide a measurement rate of 50 kHz and a detection limit in the RDE of 0.2% H 2 O by mole. The other sensor used two mid-infrared (MIR) TDLs near 2551 nm and 2482 nm that were modulated at 90 kHz and 112 kHz, respectively, and sinusoidally scanned across the peak of their respective H 2 O transitions to provide a measurement rate of 10 kHz and a detection limit in the RDE of 0.02% H 2 O by mole. Four H 2 O absorption transitions with different lower-state energies were used to assess the homogeneity of temperature in the measurement plane. Experimentally derived spectroscopic parameters that enable temperature and H 2 O sensing to within 1.5–3.5% of known values are reported. The sensor design enabling the high-bandwidth scanned-WMS-2f/1f measurements is presented. The two sensors were deployed across two orthogonal and coplanar lines-of-sight (LOS) located in the throat of a converging-diverging nozzle at the RDE combustor exit. Measurements in the non-premixed H 2 -fueled RDE indicate that the temperature and H 2 O oscillate at the detonation frequency (≈3.25 kHz) and that production of H 2 O is a weak function of global equivalence ratio. (paper)

  10. High-bandwidth scanned-wavelength-modulation spectroscopy sensors for temperature and H2O in a rotating detonation engine

    Science.gov (United States)

    Goldenstein, Christopher S.; Almodóvar, Christopher A.; Jeffries, Jay B.; Hanson, Ronald K.; Brophy, Christopher M.

    2014-10-01

    The design and use of two-color tunable diode laser (TDL) absorption sensors for measurements of temperature and H2O in a rotating detonation engine (RDE) are presented. Both sensors used first-harmonic-normalized scanned-wavelength-modulation spectroscopy with second-harmonic detection (scanned-WMS-2f/1f) to account for non-absorbing transmission losses and emission encountered in the harsh combustion environment. One sensor used two near-infrared (NIR) TDLs near 1391.7 nm and 1469.3 nm that were modulated at 225 kHz and 285 kHz, respectively, and sinusoidally scanned across the peak of their respective H2O absorption transitions to provide a measurement rate of 50 kHz and a detection limit in the RDE of 0.2% H2O by mole. The other sensor used two mid-infrared (MIR) TDLs near 2551 nm and 2482 nm that were modulated at 90 kHz and 112 kHz, respectively, and sinusoidally scanned across the peak of their respective H2O transitions to provide a measurement rate of 10 kHz and a detection limit in the RDE of 0.02% H2O by mole. Four H2O absorption transitions with different lower-state energies were used to assess the homogeneity of temperature in the measurement plane. Experimentally derived spectroscopic parameters that enable temperature and H2O sensing to within 1.5-3.5% of known values are reported. The sensor design enabling the high-bandwidth scanned-WMS-2f/1f measurements is presented. The two sensors were deployed across two orthogonal and coplanar lines-of-sight (LOS) located in the throat of a converging-diverging nozzle at the RDE combustor exit. Measurements in the non-premixed H2-fueled RDE indicate that the temperature and H2O oscillate at the detonation frequency (≈3.25 kHz) and that production of H2O is a weak function of global equivalence ratio.

  11. Parallel Microcracks-based Ultrasensitive and Highly Stretchable Strain Sensors.

    Science.gov (United States)

    Amjadi, Morteza; Turan, Mehmet; Clementson, Cameron P; Sitti, Metin

    2016-03-02

    There is an increasing demand for flexible, skin-attachable, and wearable strain sensors due to their various potential applications. However, achieving strain sensors with both high sensitivity and high stretchability is still a grand challenge. Here, we propose highly sensitive and stretchable strain sensors based on the reversible microcrack formation in composite thin films. Controllable parallel microcracks are generated in graphite thin films coated on elastomer films. Sensors made of graphite thin films with short microcracks possess high gauge factors (maximum value of 522.6) and stretchability (ε ≥ 50%), whereas sensors with long microcracks show ultrahigh sensitivity (maximum value of 11,344) with limited stretchability (ε ≤ 50%). We demonstrate the high performance strain sensing of our sensors in both small and large strain sensing applications such as human physiological activity recognition, human body large motion capturing, vibration detection, pressure sensing, and soft robotics.

  12. Direct drive digital servo press with high parallel control

    Science.gov (United States)

    Murata, Chikara; Yabe, Jun; Endou, Junichi; Hasegawa, Kiyoshi

    2013-12-01

    Direct drive digital servo press has been developed as the university-industry joint research and development since 1998. On the basis of this result, 4-axes direct drive digital servo press has been developed and in the market on April of 2002. This servo press is composed of 1 slide supported by 4 ball screws and each axis has linearscale measuring the position of each axis with high accuracy less than μm order level. Each axis is controlled independently by servo motor and feedback system. This system can keep high level parallelism and high accuracy even with high eccentric load. Furthermore the 'full stroke full power' is obtained by using ball screws. Using these features, new various types of press forming and stamping have been obtained by development and production. The new stamping and forming methods are introduced and 'manufacturing' need strategy of press forming with high added value and also the future direction of press forming are also introduced.

  13. High-Power and High-Efficiency 1.3- µm Superluminescent Diode With Flat-Top and Ultrawide Emission Bandwidth

    KAUST Repository

    Khan, Mohammed Zahed Mustafa; Alhashim, Hala H.; Ng, Tien Khee; Ooi, Boon S.

    2015-01-01

    We report on a flat-top and ultrawide emission bandwidth of 125 nm from InGaAsP/InP multiple quantum-well (MQW) superluminescent diode with antireflection coated and tilted ridge-waveguide device configuration. A total output power in excess of 70 mW with an average power spectral density of 0.56 mW/nm and spectral ripple ≤ 1.2 ± 0.5 dB is measured from the device. Wall-plug efficiency and output power as high as 14% and 80 mW, respectively, is demonstrated from this batch of devices. We attribute the broad emission to the inherent inhomogeneity of the electron-heavy-hole (e-hh) and electron-light-hole (e-lh) recombination of the ground state and the first excited state of the MQWs and their simultaneous emission.

  14. High-Power and High-Efficiency 1.3- µm Superluminescent Diode With Flat-Top and Ultrawide Emission Bandwidth

    KAUST Repository

    Khan, Mohammed Zahed Mustafa

    2015-02-01

    We report on a flat-top and ultrawide emission bandwidth of 125 nm from InGaAsP/InP multiple quantum-well (MQW) superluminescent diode with antireflection coated and tilted ridge-waveguide device configuration. A total output power in excess of 70 mW with an average power spectral density of 0.56 mW/nm and spectral ripple ≤ 1.2 ± 0.5 dB is measured from the device. Wall-plug efficiency and output power as high as 14% and 80 mW, respectively, is demonstrated from this batch of devices. We attribute the broad emission to the inherent inhomogeneity of the electron-heavy-hole (e-hh) and electron-light-hole (e-lh) recombination of the ground state and the first excited state of the MQWs and their simultaneous emission.

  15. Highly parallel line-based image coding for many cores.

    Science.gov (United States)

    Peng, Xiulian; Xu, Jizheng; Zhou, You; Wu, Feng

    2012-01-01

    Computers are developing along with a new trend from the dual-core and quad-core processors to ones with tens or even hundreds of cores. Multimedia, as one of the most important applications in computers, has an urgent need to design parallel coding algorithms for compression. Taking intraframe/image coding as a start point, this paper proposes a pure line-by-line coding scheme (LBLC) to meet the need. In LBLC, an input image is processed line by line sequentially, and each line is divided into small fixed-length segments. The compression of all segments from prediction to entropy coding is completely independent and concurrent at many cores. Results on a general-purpose computer show that our scheme can get a 13.9 times speedup with 15 cores at the encoder and a 10.3 times speedup at the decoder. Ideally, such near-linear speeding relation with the number of cores can be kept for more than 100 cores. In addition to the high parallelism, the proposed scheme can perform comparatively or even better than the H.264 high profile above middle bit rates. At near-lossless coding, it outperforms H.264 more than 10 dB. At lossless coding, up to 14% bit-rate reduction is observed compared with H.264 lossless coding at the high 4:4:4 profile.

  16. High-Bandwidth Tactical-Network Data Analysis in a High-Performance-Computing (HPC) Environment: Packet-Level Analysis

    Science.gov (United States)

    2015-09-01

    individual fragments using the hash-based method. In general, fragments 6 appear in order and relatively close to each other in the file. A fragment...data product derived from the data model is shown in Fig. 5, a Google Earth12 Keyhole Markup Language (KML) file. This product includes aggregate...System BLOb binary large object FPGA field-programmable gate array HPC high-performance computing IP Internet Protocol KML Keyhole Markup Language

  17. De Novo Ultrascale Atomistic Simulations On High-End Parallel Supercomputers

    Energy Technology Data Exchange (ETDEWEB)

    Nakano, A; Kalia, R K; Nomura, K; Sharma, A; Vashishta, P; Shimojo, F; van Duin, A; Goddard, III, W A; Biswas, R; Srivastava, D; Yang, L H

    2006-09-04

    We present a de novo hierarchical simulation framework for first-principles based predictive simulations of materials and their validation on high-end parallel supercomputers and geographically distributed clusters. In this framework, high-end chemically reactive and non-reactive molecular dynamics (MD) simulations explore a wide solution space to discover microscopic mechanisms that govern macroscopic material properties, into which highly accurate quantum mechanical (QM) simulations are embedded to validate the discovered mechanisms and quantify the uncertainty of the solution. The framework includes an embedded divide-and-conquer (EDC) algorithmic framework for the design of linear-scaling simulation algorithms with minimal bandwidth complexity and tight error control. The EDC framework also enables adaptive hierarchical simulation with automated model transitioning assisted by graph-based event tracking. A tunable hierarchical cellular decomposition parallelization framework then maps the O(N) EDC algorithms onto Petaflops computers, while achieving performance tunability through a hierarchy of parameterized cell data/computation structures, as well as its implementation using hybrid Grid remote procedure call + message passing + threads programming. High-end computing platforms such as IBM BlueGene/L, SGI Altix 3000 and the NSF TeraGrid provide an excellent test grounds for the framework. On these platforms, we have achieved unprecedented scales of quantum-mechanically accurate and well validated, chemically reactive atomistic simulations--1.06 billion-atom fast reactive force-field MD and 11.8 million-atom (1.04 trillion grid points) quantum-mechanical MD in the framework of the EDC density functional theory on adaptive multigrids--in addition to 134 billion-atom non-reactive space-time multiresolution MD, with the parallel efficiency as high as 0.998 on 65,536 dual-processor BlueGene/L nodes. We have also achieved an automated execution of hierarchical QM

  18. Chemical Industry Bandwidth Study

    Energy Technology Data Exchange (ETDEWEB)

    none,

    2006-12-01

    The Chemical Bandwidth Study provides a snapshot of potentially recoverable energy losses during chemical manufacturing. The advantage of this study is the use of "exergy" analysis as a tool for pinpointing inefficiencies.

  19. Bandwidth efficient coding

    CERN Document Server

    Anderson, John B

    2017-01-01

    Bandwidth Efficient Coding addresses the major challenge in communication engineering today: how to communicate more bits of information in the same radio spectrum. Energy and bandwidth are needed to transmit bits, and bandwidth affects capacity the most. Methods have been developed that are ten times as energy efficient at a given bandwidth consumption as simple methods. These employ signals with very complex patterns and are called "coding" solutions. The book begins with classical theory before introducing new techniques that combine older methods of error correction coding and radio transmission in order to create narrowband methods that are as efficient in both spectrum and energy as nature allows. Other topics covered include modulation techniques such as CPM, coded QAM and pulse design.

  20. Parallelization of an existing high energy physics event reconstruction software package

    International Nuclear Information System (INIS)

    Schiefer, R.; Francis, D.

    1996-01-01

    Software parallelization allows an efficient use of available computing power to increase the performance of applications. In a case study the authors have investigated the parallelization of high energy physics event reconstruction software in terms of costs (effort, computing resource requirements), benefits (performance increase) and the feasibility of a systematic parallelization approach. Guidelines facilitating a parallel implementation are proposed for future software development

  1. Glass Industry Bandwidth Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Rue, David M. [Gas Technology Inst., Des Plaines, IL (United States)

    2006-07-01

    This is a study on energy use and potential savings, or "bandwidth" study, for several glassmaking processes. Intended to provide a realistic estimate of the potential amount of energy that can be saved in an industrial process, the "bandwidth" refers to the difference between the amount of energy that would be consumed in a process using commercially available technology versus the minimum amount of energy needed to achieve those same results.

  2. Industrial Glass Bandwidth Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Rue, David M. [Gas Technology Inst., Des Plaines, IL (United States); Servaites, James [Gas Technology Inst., Des Plaines, IL (United States); Wolf, Warren [Gas Technology Inst., Des Plaines, IL (United States)

    2007-08-01

    This is a study on energy use and potential savings, or "bandwidth" study, for several glassmaking processes. Intended to provide a realistic estimate of the potential amount of energy that can be saved in an industrial process, the "bandwidth" refers to the difference between the amount of energy that would be consumed in a process using commercially available technology versus the minimum amount of energy needed to achieve those same results.

  3. Highly uniform parallel microfabrication using a large numerical aperture system

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Zi-Yu; Su, Ya-Hui, E-mail: ustcsyh@ahu.edu.cn, E-mail: dongwu@ustc.edu.cn [School of Electrical Engineering and Automation, Anhui University, Hefei 230601 (China); Zhang, Chen-Chu; Hu, Yan-Lei; Wang, Chao-Wei; Li, Jia-Wen; Chu, Jia-Ru; Wu, Dong, E-mail: ustcsyh@ahu.edu.cn, E-mail: dongwu@ustc.edu.cn [CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei 230026 (China)

    2016-07-11

    In this letter, we report an improved algorithm to produce accurate phase patterns for generating highly uniform diffraction-limited multifocal arrays in a large numerical aperture objective system. It is shown that based on the original diffraction integral, the uniformity of the diffraction-limited focal arrays can be improved from ∼75% to >97%, owing to the critical consideration of the aperture function and apodization effect associated with a large numerical aperture objective. The experimental results, e.g., 3 × 3 arrays of square and triangle, seven microlens arrays with high uniformity, further verify the advantage of the improved algorithm. This algorithm enables the laser parallel processing technology to realize uniform microstructures and functional devices in the microfabrication system with a large numerical aperture objective.

  4. Overview of Parallel Platforms for Common High Performance Computing

    Directory of Open Access Journals (Sweden)

    T. Fryza

    2012-04-01

    Full Text Available The paper deals with various parallel platforms used for high performance computing in the signal processing domain. More precisely, the methods exploiting the multicores central processing units such as message passing interface and OpenMP are taken into account. The properties of the programming methods are experimentally proved in the application of a fast Fourier transform and a discrete cosine transform and they are compared with the possibilities of MATLAB's built-in functions and Texas Instruments digital signal processors with very long instruction word architectures. New FFT and DCT implementations were proposed and tested. The implementation phase was compared with CPU based computing methods and with possibilities of the Texas Instruments digital signal processing library on C6747 floating-point DSPs. The optimal combination of computing methods in the signal processing domain and new, fast routines' implementation is proposed as well.

  5. Parallelization of MCNP 4, a Monte Carlo neutron and photon transport code system, in highly parallel distributed memory type computer

    International Nuclear Information System (INIS)

    Masukawa, Fumihiro; Takano, Makoto; Naito, Yoshitaka; Yamazaki, Takao; Fujisaki, Masahide; Suzuki, Koichiro; Okuda, Motoi.

    1993-11-01

    In order to improve the accuracy and calculating speed of shielding analyses, MCNP 4, a Monte Carlo neutron and photon transport code system, has been parallelized and measured of its efficiency in the highly parallel distributed memory type computer, AP1000. The code has been analyzed statically and dynamically, then the suitable algorithm for parallelization has been determined for the shielding analysis functions of MCNP 4. This includes a strategy where a new history is assigned to the idling processor element dynamically during the execution. Furthermore, to avoid the congestion of communicative processing, the batch concept, processing multi-histories by a unit, has been introduced. By analyzing a sample cask problem with 2,000,000 histories by the AP1000 with 512 processor elements, the 82 % of parallelization efficiency is achieved, and the calculational speed has been estimated to be around 50 times as fast as that of FACOM M-780. (author)

  6. Simple, parallel, high-performance virtual machines for extreme computations

    International Nuclear Information System (INIS)

    Chokoufe Nejad, Bijan; Ohl, Thorsten; Reuter, Jurgen

    2014-11-01

    We introduce a high-performance virtual machine (VM) written in a numerically fast language like Fortran or C to evaluate very large expressions. We discuss the general concept of how to perform computations in terms of a VM and present specifically a VM that is able to compute tree-level cross sections for any number of external legs, given the corresponding byte code from the optimal matrix element generator, O'Mega. Furthermore, this approach allows to formulate the parallel computation of a single phase space point in a simple and obvious way. We analyze hereby the scaling behaviour with multiple threads as well as the benefits and drawbacks that are introduced with this method. Our implementation of a VM can run faster than the corresponding native, compiled code for certain processes and compilers, especially for very high multiplicities, and has in general runtimes in the same order of magnitude. By avoiding the tedious compile and link steps, which may fail for source code files of gigabyte sizes, new processes or complex higher order corrections that are currently out of reach could be evaluated with a VM given enough computing power.

  7. Highly parallel algorithm for high pT physics at FAIR-CBM

    International Nuclear Information System (INIS)

    Fueloep, A; Vesztergombi, G

    2010-01-01

    The limitations of presently available data on p T range are discussed and planned future upgrades are outlined. Special attention is given to the FAIR-CBM experiment as a unique high luminosity facility for future continuation of the measurements at very high p T with emphasis on the so-called mosaic trigger system to use the highly parallel online algorithm.

  8. Analysis and Design of High-Order Parallel Resonant Converters

    Science.gov (United States)

    Batarseh, Issa Eid

    1990-01-01

    In this thesis, a special state variable transformation technique has been derived for the analysis of high order dc-to-dc resonant converters. Converters comprised of high order resonant tanks have the advantage of utilizing the parasitic elements by making them part of the resonant tank. A new set of state variables is defined in order to make use of two-dimensional state-plane diagrams in the analysis of high order converters. Such a method has been successfully used for the analysis of the conventional Parallel Resonant Converters (PRC). Consequently, two -dimensional state-plane diagrams are used to analyze the steady state response for third and fourth order PRC's when these converters are operated in the continuous conduction mode. Based on this analysis, a set of control characteristic curves for the LCC-, LLC- and LLCC-type PRC are presented from which various converter design parameters are obtained. Various design curves for component value selections and device ratings are given. This analysis of high order resonant converters shows that the addition of the reactive components to the resonant tank results in converters with better performance characteristics when compared with the conventional second order PRC. Complete design procedure along with design examples for 2nd, 3rd and 4th order converters are presented. Practical power supply units, normally used for computer applications, were built and tested by using the LCC-, LLC- and LLCC-type commutation schemes. In addition, computer simulation results are presented for these converters in order to verify the theoretical results.

  9. High accurate volume holographic correlator with 4000 parallel correlation channels

    Science.gov (United States)

    Ni, Kai; Qu, Zongyao; Cao, Liangcai; Su, Ping; He, Qingsheng; Jin, Guofan

    2008-03-01

    Volume holographic correlator allows simultaneously calculate the two-dimensional inner product between the input image and each stored image. We have recently experimentally implemented in VHC 4000 parallel correlation channels with better than 98% output accuracy in a single location in a crystal. The speckle modulation is used to suppress the sidelobes of the correlation patterns, allowing more correlation spots to be contained in the output plane. A modified exposure schedule is designed to ensure the hologram in each channel with unity diffraction efficiency. In this schedule, a restricted coefficient was introduced into the original exposure schedule to solve the problem that the sensitivity and time constant of the crystal will change as a time function when in high-capacity storage. An interleaving method is proposed to improve the output accuracy. By unifying the distribution of the input and stored image patterns without changing the inner products between them, this method could eliminate the impact of correlation pattern variety on calculated inner product values. Moreover, by using this method, the maximum correlation spot size is reduced, which decreases the required minimum safe clearance between neighboring spots in the output plane, allowing more spots to be parallely detected without crosstalk. The experimental results are given and analyzed.

  10. Language interoperability for high-performance parallel scientific components

    International Nuclear Information System (INIS)

    Elliot, N; Kohn, S; Smolinski, B

    1999-01-01

    With the increasing complexity and interdisciplinary nature of scientific applications, code reuse is becoming increasingly important in scientific computing. One method for facilitating code reuse is the use of components technologies, which have been used widely in industry. However, components have only recently worked their way into scientific computing. Language interoperability is an important underlying technology for these component architectures. In this paper, we present an approach to language interoperability for a high-performance parallel, component architecture being developed by the Common Component Architecture (CCA) group. Our approach is based on Interface Definition Language (IDL) techniques. We have developed a Scientific Interface Definition Language (SIDL), as well as bindings to C and Fortran. We have also developed a SIDL compiler and run-time library support for reference counting, reflection, object management, and exception handling (Babel). Results from using Babel to call a standard numerical solver library (written in C) from C and Fortran show that the cost of using Babel is minimal, where as the savings in development time and the benefits of object-oriented development support for C and Fortran far outweigh the costs

  11. A novel highly parallel algorithm for linearly unmixing hyperspectral images

    Science.gov (United States)

    Guerra, Raúl; López, Sebastián.; Callico, Gustavo M.; López, Jose F.; Sarmiento, Roberto

    2014-10-01

    Endmember extraction and abundances calculation represent critical steps within the process of linearly unmixing a given hyperspectral image because of two main reasons. The first one is due to the need of computing a set of accurate endmembers in order to further obtain confident abundance maps. The second one refers to the huge amount of operations involved in these time-consuming processes. This work proposes an algorithm to estimate the endmembers of a hyperspectral image under analysis and its abundances at the same time. The main advantage of this algorithm is its high parallelization degree and the mathematical simplicity of the operations implemented. This algorithm estimates the endmembers as virtual pixels. In particular, the proposed algorithm performs the descent gradient method to iteratively refine the endmembers and the abundances, reducing the mean square error, according with the linear unmixing model. Some mathematical restrictions must be added so the method converges in a unique and realistic solution. According with the algorithm nature, these restrictions can be easily implemented. The results obtained with synthetic images demonstrate the well behavior of the algorithm proposed. Moreover, the results obtained with the well-known Cuprite dataset also corroborate the benefits of our proposal.

  12. Highly parallel translation of DNA sequences into small molecules.

    Directory of Open Access Journals (Sweden)

    Rebecca M Weisinger

    Full Text Available A large body of in vitro evolution work establishes the utility of biopolymer libraries comprising 10(10 to 10(15 distinct molecules for the discovery of nanomolar-affinity ligands to proteins. Small-molecule libraries of comparable complexity will likely provide nanomolar-affinity small-molecule ligands. Unlike biopolymers, small molecules can offer the advantages of cell permeability, low immunogenicity, metabolic stability, rapid diffusion and inexpensive mass production. It is thought that such desirable in vivo behavior is correlated with the physical properties of small molecules, specifically a limited number of hydrogen bond donors and acceptors, a defined range of hydrophobicity, and most importantly, molecular weights less than 500 Daltons. Creating a collection of 10(10 to 10(15 small molecules that meet these criteria requires the use of hundreds to thousands of diversity elements per step in a combinatorial synthesis of three to five steps. With this goal in mind, we have reported a set of mesofluidic devices that enable DNA-programmed combinatorial chemistry in a highly parallel 384-well plate format. Here, we demonstrate that these devices can translate DNA genes encoding 384 diversity elements per coding position into corresponding small-molecule gene products. This robust and efficient procedure yields small molecule-DNA conjugates suitable for in vitro evolution experiments.

  13. Highly Parallelized Pattern Matching Execution for the ATLAS Experiment

    CERN Document Server

    Citraro, Saverio; The ATLAS collaboration

    2015-01-01

    The trigger system of the ATLAS experiment at LHC will extend its rejection capabilities during operations in 2015-2018 by introducing the Fast TracKer system (FTK). FTK is a hardware based system capable of finding charged particle tracks by analyzing hits in silicon detectors at the rate of 105 events per second. The core of track reconstruction is performed into two pipelined steps. At first step the candidate tracks are found by matching combination of low resolution hits to predefined patterns; then they are used in the second step to seed a more precise track fitting algorithm. The key FTK component is an Associative Memory (AM) system that is used to perform pattern matching with high degree of parallelism. The AM system implementation, the AM Serial Link Processor, is based on an extremely powerful network of 2 Gb/s serial links to sustain a huge traffic of data. We report on the design of the Serial Link Processor consisting of two types of boards, the Little Associative Memory Board (LAMB), a mezzan...

  14. Highly Parallelized Pattern Matching Execution for the ATLAS Experiment

    CERN Document Server

    Citraro, Saverio; The ATLAS collaboration

    2015-01-01

    Abstract– The Associative Memory (AM) system of the Fast Tracker (FTK) processor has been designed to perform pattern matching using as input the data from the silicon tracker in the ATLAS experiment. The AM is the primary component of the FTK system and is designed using ASIC technology (the AM chip) to execute pattern matching with a high degree of parallelism. The FTK system finds track candidates at low resolution that are seeds for a full resolution track fitting. The AM system implementation is named “Serial Link Processor” and is based on an extremely powerful network of 2 Gb/s serial links to sustain a huge traffic of data. This paper reports on the design of the Serial Link Processor consisting of two types of boards, the Little Associative Memory Board (LAMB), a mezzanine where the AM chips are mounted, and the Associative Memory Board (AMB), a 9U VME motherboard which hosts four LAMB daughterboards. We also report on the performance of the prototypes (both hardware and firmware) produced and ...

  15. Combination of fat saturation and variable bandwidth imaging to increase signal-to-noise ratio and decrease motion artifacts for body MR imaging at high field

    International Nuclear Information System (INIS)

    Chew, W.M.

    1989-01-01

    The signal-to-noise ratio (SNR) of the MR imaging examination is a critical component of the quality of the image. Standard methods to increase SNR include signal averaging with multiple excitations, at the expense of imaging time (which on T2-weighted images could be quite significant), or increasing pixel volume by manipulation of field of view, matrix size, and/or section thickness, all at the expense of resolution. Another available method to increase SNR is to reduce the bandwidth of the receiver, which increases SNR by the square root of the amount of the reduction. The penalty imposed on high-field-strength MR examinations of the body is an unacceptable increase in chemical shift artifact. However, presaturating the fat resonance eliminates the chemical shift artifact. Thus, a combination of imaging techniques, fat suppression, and decreased bandwidth imaging can produce images free of chemical shift artifact with increased SNR and no penalty in resolution or imaging time. Early studies also show a reduction in motion artifact when fat saturation is used. This paper reports MR imaging performed with a 1.5-T Signa imager. With this technique, T2-weighted images (2,500/20/80 [repetition time msec/echo time msec/inversion time msec]) illustrating the increase in SNR and T1-weighted images (600/20) demonstrating a decrease in motion artifact are shown

  16. The Galley Parallel File System

    Science.gov (United States)

    Nieuwejaar, Nils; Kotz, David

    1996-01-01

    Most current multiprocessor file systems are designed to use multiple disks in parallel, using the high aggregate bandwidth to meet the growing I/0 requirements of parallel scientific applications. Many multiprocessor file systems provide applications with a conventional Unix-like interface, allowing the application to access multiple disks transparently. This interface conceals the parallelism within the file system, increasing the ease of programmability, but making it difficult or impossible for sophisticated programmers and libraries to use knowledge about their I/O needs to exploit that parallelism. In addition to providing an insufficient interface, most current multiprocessor file systems are optimized for a different workload than they are being asked to support. We introduce Galley, a new parallel file system that is intended to efficiently support realistic scientific multiprocessor workloads. We discuss Galley's file structure and application interface, as well as the performance advantages offered by that interface.

  17. High-Performance Psychometrics: The Parallel-E Parallel-M Algorithm for Generalized Latent Variable Models. Research Report. ETS RR-16-34

    Science.gov (United States)

    von Davier, Matthias

    2016-01-01

    This report presents results on a parallel implementation of the expectation-maximization (EM) algorithm for multidimensional latent variable models. The developments presented here are based on code that parallelizes both the E step and the M step of the parallel-E parallel-M algorithm. Examples presented in this report include item response…

  18. Source parameters and effects of bandwidth and local geology on high- frequency ground motions observed for aftershocks of the northeastern Ohio earthquake of 31 January 1986

    Science.gov (United States)

    Glassmoyer, G.; Borcherdt, R.D.

    1990-01-01

    A 10-station array (GEOS) yielded recordings of exceptional bandwidth (400 sps) and resolution (up to 96 dB) for the aftershocks of the moderate (mb???4.9) earthquake that occurred on 31 January 1986 near Painesville, Ohio. Nine aftershocks were recorded with seismic moments ranging between 9 ?? 1016 and 3 ?? 1019 dyne-cm (MW: 0.6 to 2.3). The aftershock recordings at a site underlain by ???8m of lakeshore sediments show significant levels of high-frequency soil amplification of vertical motion at frequencies near 8, 20 and 70 Hz. Viscoelastic models for P and SV waves incident at the base of the sediments yield estimates of vertical P-wave response consistent with the observed high-frequency site resonances, but suggest additional detailed shear-wave logs are needed to account for observed S-wave response. -from Authors

  19. Highly parallel machines and future of scientific computing

    International Nuclear Information System (INIS)

    Singh, G.S.

    1992-01-01

    Computing requirement of large scale scientific computing has always been ahead of what state of the art hardware could supply in the form of supercomputers of the day. And for any single processor system the limit to increase in the computing power was realized a few years back itself. Now with the advent of parallel computing systems the availability of machines with the required computing power seems a reality. In this paper the author tries to visualize the future large scale scientific computing in the penultimate decade of the present century. The author summarized trends in parallel computers and emphasize the need for a better programming environment and software tools for optimal performance. The author concludes this paper with critique on parallel architectures, software tools and algorithms. (author). 10 refs., 2 tabs

  20. A high performance parallel approach to medical imaging

    International Nuclear Information System (INIS)

    Frieder, G.; Frieder, O.; Stytz, M.R.

    1988-01-01

    Research into medical imaging using general purpose parallel processing architectures is described and a review of the performance of previous medical imaging machines is provided. Results demonstrating that general purpose parallel architectures can achieve performance comparable to other, specialized, medical imaging machine architectures is presented. A new back-to-front hidden-surface removal algorithm is described. Results demonstrating the computational savings obtained by using the modified back-to-front hidden-surface removal algorithm are presented. Performance figures for forming a full-scale medical image on a mesh interconnected multiprocessor are presented

  1. Efficient Bandwidth Management for Ethernet Passive Optical Networks

    KAUST Repository

    Elrasad, Amr Elsayed M.

    2016-05-15

    Polling (EGSIP), to compensate the unutilized bandwidth due to frame delineation. Our solution achieves delay reduction ratio up to 90% at high load. We also develop a Congestion Aware Limited Time (CALT) DBA scheme to detect and resolve temporary congestion in EPONs. CALT smartly adapts the optical networking unit (ONU) maximum transmission window according to the detected congestion level. Numerical results show that CALT is more robust at high load compared to other related published schemes. Regarding LR-EPONs, the main concern is large round trip delay mitigation. We address two problems, namely bandwidth over-granting in Multi-Thread Polling (MTP) and on-the-fly void filling. We combine, with some modifications, EGSIP and DES to resolve bandwidth over-granting in MTP. We also manage to adaptively tune MTP active running threads along with the offered load. Regarding on-the-fly void filling, Our approach, Parallel Void Thread (PVT), achieves large delay reduction for delay-sensitive traffic. PVT is designed as a plus function to DBA and can be combined with almost all DBA schemes proposed before. The powerful feature of our proposed solutions is integrability. We integrate our solutions together and form a multi-feature, robust, fairly simple, and well performing DBA scheme over LR-TWDM-EPONs. Our final contribution is about energy saving under target delay constraints. We tackle the problem of downstream based sleep time sizing and scheduling under required delay constraints. Simulation results show that our approach adheres to delay constraints and achieves almost ideal energy saving ratio at the same time.

  2. Low Group Delay Dispersion Optical Coating for Broad Bandwidth High Reflection at 45° Incidence, P Polarization of Femtosecond Pulses with 900 nm Center Wavelength

    Directory of Open Access Journals (Sweden)

    John C. Bellum

    2016-03-01

    Full Text Available We describe an optical coating design suitable for broad bandwidth high reflection (BBHR at 45° angle of incidence (AOI, P polarization (Ppol of femtosecond (fs laser pulses whose wavelengths range from 800 to 1000 nm. Our design process is guided by quarter-wave HR coating properties. The design must afford low group delay dispersion (GDD for reflected light over the broad, 200 nm bandwidth in order to minimize temporal broadening of the fs pulses due to dispersive alteration of relative phases between their frequency components. The design should also be favorable to high laser-induced damage threshold (LIDT. We base the coating on TiO2/SiO2 layer pairs produced by means of e-beam evaporation with ion-assisted deposition, and use OptiLayer Thin Film Software to explore designs starting with TiO2/SiO2 layers having thicknesses in a reverse chirped arrangement. This approach led to a design with R > 99% from 800 to 1000 nm and GDD < 20 fs2 from 843 to 949 nm (45° AOI, Ppol. The design’s GDD behaves in a smooth way, suitable for GDD compensation techniques, and its electric field intensities show promise for high LIDTs. Reflectivity and GDD measurements for the initial test coating indicate good performance of the BBHR design. Subsequent coating runs with improved process calibration produced two coatings whose HR bands satisfactorily meet the design goals. For the sake of completeness, we summarize our previously reported transmission spectra and LIDT test results with 800 ps, 8 ps and 675 fs pulses for these two coatings, and present a table of the LIDT results we have for all of our TiO2/SiO2 BBHR coatings, showing the trends with test laser pulse duration from the ns to sub-ps regimes.

  3. Design of high-performance parallelized gene predictors in MATLAB.

    Science.gov (United States)

    Rivard, Sylvain Robert; Mailloux, Jean-Gabriel; Beguenane, Rachid; Bui, Hung Tien

    2012-04-10

    This paper proposes a method of implementing parallel gene prediction algorithms in MATLAB. The proposed designs are based on either Goertzel's algorithm or on FFTs and have been implemented using varying amounts of parallelism on a central processing unit (CPU) and on a graphics processing unit (GPU). Results show that an implementation using a straightforward approach can require over 4.5 h to process 15 million base pairs (bps) whereas a properly designed one could perform the same task in less than five minutes. In the best case, a GPU implementation can yield these results in 57 s. The present work shows how parallelism can be used in MATLAB for gene prediction in very large DNA sequences to produce results that are over 270 times faster than a conventional approach. This is significant as MATLAB is typically overlooked due to its apparent slow processing time even though it offers a convenient environment for bioinformatics. From a practical standpoint, this work proposes two strategies for accelerating genome data processing which rely on different parallelization mechanisms. Using a CPU, the work shows that direct access to the MEX function increases execution speed and that the PARFOR construct should be used in order to take full advantage of the parallelizable Goertzel implementation. When the target is a GPU, the work shows that data needs to be segmented into manageable sizes within the GFOR construct before processing in order to minimize execution time.

  4. Variable pattern of high-order harmonic spectra from a laser-produced plasma by using the chirped pulses of narrow-bandwidth radiation

    International Nuclear Information System (INIS)

    Ganeev, R. A.; Suzuki, M.; Baba, M.; Kuroda, H.; Redkin, P. V.

    2007-01-01

    Various plasmas prepared by laser ablation of the surfaces of solid targets were examined by the narrow-bandwidth radiation of different chirp and pulse durations. The high-order harmonics generated during laser-plasma interaction showed different brightness, wavelength shift, harmonic cutoff, and efficiency by using variable chirps of pump radiation. An analysis of harmonic optimization at these conditions is presented. The blueshifted and redshifted harmonics observed in this case were analyzed and attributed to the abundance of free electrons and self-phase modulation of the driving pulse. The resonance-induced enhancement of the 15th harmonic from GaN-nanoparticle-containing plasma caused by the tuning of harmonic wavelength close to the ionic transition was demonstrated

  5. Connectionist Models and Parallelism in High Level Vision.

    Science.gov (United States)

    1985-01-01

    GRANT NUMBER(s) Jerome A. Feldman N00014-82-K-0193 9. PERFORMING ORGANIZATION NAME AND ADDRESS 10. PROGRAM ELEMENt. PROJECT, TASK Computer Science...Connectionist Models 2.1 Background and Overviev % Computer science is just beginning to look seriously at parallel computation : it may turn out that...the chair. The program includes intermediate level networks that compute more complex joints and ones that compute parallelograms in the image. These

  6. Radiation-hard/high-speed parallel optical links

    Energy Technology Data Exchange (ETDEWEB)

    Gan, K.K., E-mail: gan@mps.ohio-state.edu [Department of Physics, The Ohio State University, Columbus, OH 43210 (United States); Buchholz, P.; Heidbrink, S. [Fachbereich Physik, Universität Siegen, Siegen (Germany); Kagan, H.P.; Kass, R.D.; Moore, J.; Smith, D.S. [Department of Physics, The Ohio State University, Columbus, OH 43210 (United States); Vogt, M.; Ziolkowski, M. [Fachbereich Physik, Universität Siegen, Siegen (Germany)

    2016-09-21

    We have designed and fabricated a compact parallel optical engine for transmitting data at 5 Gb/s. The device consists of a 4-channel ASIC driving a VCSEL (Vertical Cavity Surface Emitting Laser) array in an optical package. The ASIC is designed using only core transistors in a 65 nm CMOS process to enhance the radiation-hardness. The ASIC contains an 8-bit DAC to control the bias and modulation currents of the individual channels in the VCSEL array. The performance of the optical engine up at 5 Gb/s is satisfactory.

  7. Bandwidth extension of speech using perceptual criteria

    CERN Document Server

    Berisha, Visar; Liss, Julie

    2013-01-01

    Bandwidth extension of speech is used in the International Telecommunication Union G.729.1 standard in which the narrowband bitstream is combined with quantized high-band parameters. Although this system produces high-quality wideband speech, the additional bits used to represent the high band can be further reduced. In addition to the algorithm used in the G.729.1 standard, bandwidth extension methods based on spectrum prediction have also been proposed. Although these algorithms do not require additional bits, they perform poorly when the correlation between the low and the high band is weak. In this book, two wideband speech coding algorithms that rely on bandwidth extension are developed. The algorithms operate as wrappers around existing narrowband compression schemes. More specifically, in these algorithms, the low band is encoded using an existing toll-quality narrowband system, whereas the high band is generated using the proposed extension techniques. The first method relies only on transmitted high-...

  8. Parallel interconnect for a novel system approach to short distance high information transfer data links

    Science.gov (United States)

    Raskin, Glenn; Lebby, Michael S.; Carney, F.; Kazakia, M.; Schwartz, Daniel B.; Gaw, Craig A.

    1997-04-01

    architecture uses AlGaAs vertical cavity surface emitting lasers (VCSELs) at 850 nm in conjunction with unique opto-electronic packaging concepts. Most laser based transmitter subsystems are incapable of carrying an arbitrary NRZ data stream at high data rates. The receiver subsystem utilizes a conventional GaAs PIN photo-detector. In parallel interconnect systems. The design must take into account the simultaneous switching noise from the neighboring systems. If not well controlled, the high density of the multiple interconnects can limit the sensitivity and therefore the performance of the system. The packaging approach of the VCSEL and PIN arrays allow for high bandwidths and provide the coupling mechanisms necessary to interface to the 62.5 micrometer multi mode fiber. To allow for extremely high electrical signals the OPTOBUSTM package utilizes a multilayer tape automated bonded (TAB) lead frame. The lead frame contains separate signal and ground layers. The ground layer successfully provides for a pseudo-coaxial environment (low inductance and effective signal coupling to the ground plane).

  9. Introduction to massively-parallel computing in high-energy physics

    CERN Document Server

    AUTHOR|(CDS)2083520

    1993-01-01

    Ever since computers were first used for scientific and numerical work, there has existed an "arms race" between the technical development of faster computing hardware, and the desires of scientists to solve larger problems in shorter time-scales. However, the vast leaps in processor performance achieved through advances in semi-conductor science have reached a hiatus as the technology comes up against the physical limits of the speed of light and quantum effects. This has lead all high performance computer manufacturers to turn towards a parallel architecture for their new machines. In these lectures we will introduce the history and concepts behind parallel computing, and review the various parallel architectures and software environments currently available. We will then introduce programming methodologies that allow efficient exploitation of parallel machines, and present case studies of the parallelization of typical High Energy Physics codes for the two main classes of parallel computing architecture (S...

  10. High-bandwidth prefetcher for high-bandwidth memory

    Science.gov (United States)

    Mehta, Sanyam; Kohn, James Robert; Ernst, Daniel Jonathan; Poxon, Heidi Lynn; DeRose, Luiz

    2018-04-17

    A method for prefetching data into a cache is provided. The method allocates an outstanding request buffer ("ORB"). The method stores in an address field of the ORB an address and a number of blocks. The method issues prefetch requests for a degree number of blocks starting at the address. When a prefetch response is received for all the prefetch requests, the method adjusts the address of the next block to prefetch and adjusts the number of blocks remaining to be retrieved and then issues prefetch requests for a degree number of blocks starting at the adjusted address. The prefetching pauses when a maximum distance between the reads of the prefetched blocks and the last prefetched block is reached. When a read request for a prefetched block is received, the method resumes prefetching when a resume criterion is satisfied.

  11. Ultrahigh bandwidth signal processing

    DEFF Research Database (Denmark)

    Oxenløwe, Leif Katsuo

    2016-01-01

    Optical time lenses have proven to be very versatile for advanced optical signal processing. Based on a controlled interplay between dispersion and phase-modulation by e.g. four-wave mixing, the processing is phase-preserving, an hence useful for all types of data signals including coherent multi......-level modulation founats. This has enabled processing of phase-modulated spectrally efficient data signals, such as orthogonal frequency division multiplexed (OFDM) signa In that case, a spectral telescope system was used, using two time lenses with different focal lengths (chirp rates), yielding a spectral...... regeneratio These operations require a broad bandwidth nonlinear platform, and novel photonic integrated nonlinear platform like aluminum gallium arsenide nano-waveguides used for 1.28 Tbaud optical signal processing will be described....

  12. The Permanent Magnet Operating Mechanism of Double Coil Parallel Driven at a High Speed

    Directory of Open Access Journals (Sweden)

    WEI Xau-Lao

    2017-02-01

    Full Text Available Abstract:Operating mechanism is the main part of breaker,and the quality of breaker will directly influence the safe operation of power system. Because of the continuous improvement requirements of switch,in order to mak this actuator faster and more powerful closing,this paper proposes a double coil parallel driven permanent magnet actuator at a high speed. This paper expounds the working principle of single and double coil parallel driven permanent magnet actuator. It uses Ansoft building model and contrasts test results. In prance we designed and produced the single and double coil parallel driven permanent magnet actuator for experimental study. The simulation and experiment results show that double coil parallel driven permanent magnet actuator,compared with single coil parallel driven permanent magnet actuator,has a better and faster action performance. Thus,the double coil parallel driven permanent magnet actuator achieves a kind of optimization.

  13. GROMACS 4.5: A high-throughput and highly parallel open source molecular simulation toolkit

    Energy Technology Data Exchange (ETDEWEB)

    Pronk, Sander [Science for Life Lab., Stockholm (Sweden); KTH Royal Institute of Technology, Stockholm (Sweden); Pall, Szilard [Science for Life Lab., Stockholm (Sweden); KTH Royal Institute of Technology, Stockholm (Sweden); Schulz, Roland [Univ. of Tennessee, Knoxville, TN (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Larsson, Per [Univ. of Virginia, Charlottesville, VA (United States); Bjelkmar, Par [Science for Life Lab., Stockholm (Sweden); Stockholm Univ., Stockholm (Sweden); Apostolov, Rossen [Science for Life Lab., Stockholm (Sweden); KTH Royal Institute of Technology, Stockholm (Sweden); Shirts, Michael R. [Univ. of Virginia, Charlottesville, VA (United States); Smith, Jeremy C. [Univ. of Tennessee, Knoxville, TN (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Kasson, Peter M. [Univ. of Virginia, Charlottesville, VA (United States); van der Spoel, David [Science for Life Lab., Stockholm (Sweden); Uppsala Univ., Uppsala (Sweden); Hess, Berk [Science for Life Lab., Stockholm (Sweden); KTH Royal Institute of Technology, Stockholm (Sweden); Lindahl, Erik [Science for Life Lab., Stockholm (Sweden); KTH Royal Institute of Technology, Stockholm (Sweden); Stockholm Univ., Stockholm (Sweden)

    2013-02-13

    In this study, molecular simulation has historically been a low-throughput technique, but faster computers and increasing amounts of genomic and structural data are changing this by enabling large-scale automated simulation of, for instance, many conformers or mutants of biomolecules with or without a range of ligands. At the same time, advances in performance and scaling now make it possible to model complex biomolecular interaction and function in a manner directly testable by experiment. These applications share a need for fast and efficient software that can be deployed on massive scale in clusters, web servers, distributed computing or cloud resources. As a result, we present a range of new simulation algorithms and features developed during the past 4 years, leading up to the GROMACS 4.5 software package. The software now automatically handles wide classes of biomolecules, such as proteins, nucleic acids and lipids, and comes with all commonly used force fields for these molecules built-in. GROMACS supports several implicit solvent models, as well as new free-energy algorithms, and the software now uses multithreading for efficient parallelization even on low-end systems, including windows-based workstations. Together with hand-tuned assembly kernels and state-of-the-art parallelization, this provides extremely high performance and cost efficiency for high-throughput as well as massively parallel simulations.

  14. GROMACS 4.5: a high-throughput and highly parallel open source molecular simulation toolkit.

    Science.gov (United States)

    Pronk, Sander; Páll, Szilárd; Schulz, Roland; Larsson, Per; Bjelkmar, Pär; Apostolov, Rossen; Shirts, Michael R; Smith, Jeremy C; Kasson, Peter M; van der Spoel, David; Hess, Berk; Lindahl, Erik

    2013-04-01

    Molecular simulation has historically been a low-throughput technique, but faster computers and increasing amounts of genomic and structural data are changing this by enabling large-scale automated simulation of, for instance, many conformers or mutants of biomolecules with or without a range of ligands. At the same time, advances in performance and scaling now make it possible to model complex biomolecular interaction and function in a manner directly testable by experiment. These applications share a need for fast and efficient software that can be deployed on massive scale in clusters, web servers, distributed computing or cloud resources. Here, we present a range of new simulation algorithms and features developed during the past 4 years, leading up to the GROMACS 4.5 software package. The software now automatically handles wide classes of biomolecules, such as proteins, nucleic acids and lipids, and comes with all commonly used force fields for these molecules built-in. GROMACS supports several implicit solvent models, as well as new free-energy algorithms, and the software now uses multithreading for efficient parallelization even on low-end systems, including windows-based workstations. Together with hand-tuned assembly kernels and state-of-the-art parallelization, this provides extremely high performance and cost efficiency for high-throughput as well as massively parallel simulations. GROMACS is an open source and free software available from http://www.gromacs.org. Supplementary data are available at Bioinformatics online.

  15. High-speed parallel solution of the neutron diffusion equation with the hierarchical domain decomposition boundary element method incorporating parallel communications

    International Nuclear Information System (INIS)

    Tsuji, Masashi; Chiba, Gou

    2000-01-01

    A hierarchical domain decomposition boundary element method (HDD-BEM) for solving the multiregion neutron diffusion equation (NDE) has been fully parallelized, both for numerical computations and for data communications, to accomplish a high parallel efficiency on distributed memory message passing parallel computers. Data exchanges between node processors that are repeated during iteration processes of HDD-BEM are implemented, without any intervention of the host processor that was used to supervise parallel processing in the conventional parallelized HDD-BEM (P-HDD-BEM). Thus, the parallel processing can be executed with only cooperative operations of node processors. The communication overhead was even the dominant time consuming part in the conventional P-HDD-BEM, and the parallelization efficiency decreased steeply with the increase of the number of processors. With the parallel data communication, the efficiency is affected only by the number of boundary elements assigned to decomposed subregions, and the communication overhead can be drastically reduced. This feature can be particularly advantageous in the analysis of three-dimensional problems where a large number of processors are required. The proposed P-HDD-BEM offers a promising solution to the deterioration problem of parallel efficiency and opens a new path to parallel computations of NDEs on distributed memory message passing parallel computers. (author)

  16. High bandwidth beam current monitor

    International Nuclear Information System (INIS)

    Baltrusaitis, R.M.; Ekdahl, C.A.; Cooper, R.G.; Peterson, E.; Warn, C.E.

    1993-01-01

    A stripline directional coupler beam current monitor capable of measuring the time structure of a 30-ps electron beam bunch has been developed. The time response performance of the monitor compares very well with Cherenkov light produced in quartz by the electron beam. The four-pickup monitor is now used on a routine basis for measuring the beam duration, tuning for optimized beam bunching, and centering the bunch in the beam pipe

  17. Teleoperation over low bandwidth communication links

    International Nuclear Information System (INIS)

    Fryer, R.J.; Mair, G.M.; Clark, N.; Heng, J.

    1996-01-01

    Teleoperation is well established for many areas of hazardous environment working. Where such environments are well structured and contained, such as within a working plant, communications bandwidths need not be a constraining factor. However where the worksite is remote, large, poorly structured or damaged communications rapidly become a critical factor in the efficient deployment and use of teleoperation equipment. The paper justifies and describes means which we are exploring to reduce the required communications bandwidth for teleoperation whist retaining full functionality. Techniques involved include incorporation of local intelligence at the worksite, with bandwidth devoted to high-level up-link control signals and down-link feedback, and the use of highly compressed video feeding 'virtual reality type' HMDs to provide maximum system transparency for the operator. The work is drawing on previous experience with an 'anthropomorphic robot heat' for telepresence work, and proprietary algorithms capable of compressing full colour video to standard telephone modem data rates. (Author)

  18. Cutter Connectivity Bandwidth Study

    Science.gov (United States)

    2002-10-01

    The goal of this study was to determine how much bandwidth is required for cutters to meet emerging data transfer requirements. The Cutter Connectivity Business Solutions Team with guidance front the Commandant's 5 Innovation Council sponsored this study. Today, many Coast Guard administrative and business functions are being conducted via electronic means. Although our larger cutters can establish part-time connectivity using commercial satellite communications (SATCOM) while underway, there are numerous complaints regarding poor application performance. Additionally, smaller cutters do not have any standard means of underway connectivity. The R&D study shows the most important factor affecting web performance and enterprise applications onboard cutters was latency. Latency describes the time it takes the signal to reach the satellite and come back down through space. The latency due to use of higher orbit satellites is causing poor application performance and inefficient use of expensive SATCOM links. To improve performance, the CC must, (1) reduce latency by using alternate communications links such as low-earth orbit satellites, (2) tailor applications to the SATCOM link and/or (3) optimize protocols used for data communication to minimize time required by present applications to establish communications between the user and the host systems.

  19. Very broad bandwidth klystron amplifiers

    Science.gov (United States)

    Faillon, G.; Egloff, G.; Farvet, C.

    Large surveillance radars use transmitters at peak power levels of around one MW and average levels of a few kW, and possibly several tens of kW, in S band, or even C band. In general, the amplification stage of these transmitters is a microwave power tube, frequently a klystron. Although designers often turn to klystrons because of their good peak and average power capabilities, they still see them as narrow band amplifiers, undoubtedly because of their resonant cavities which, at first sight, would seem highly selective. But, with the progress of recent years, it has now become quite feasible to use these tubes in installations requiring bandwidths in excess of 10 - 12 percent, and even 15 percent, at 1 MW peak for example, in S-band.

  20. Adapting high-level language programs for parallel processing using data flow

    Science.gov (United States)

    Standley, Hilda M.

    1988-01-01

    EASY-FLOW, a very high-level data flow language, is introduced for the purpose of adapting programs written in a conventional high-level language to a parallel environment. The level of parallelism provided is of the large-grained variety in which parallel activities take place between subprograms or processes. A program written in EASY-FLOW is a set of subprogram calls as units, structured by iteration, branching, and distribution constructs. A data flow graph may be deduced from an EASY-FLOW program.

  1. High-speed parallel forward error correction for optical transport networks

    DEFF Research Database (Denmark)

    Rasmussen, Anders; Ruepp, Sarah Renée; Berger, Michael Stübert

    2010-01-01

    This paper presents a highly parallelized hardware implementation of the standard OTN Reed-Solomon Forward Error Correction algorithm. The proposed circuit is designed to meet the immense throughput required by OTN4, using commercially available FPGA technology....

  2. Improved-Bandwidth Transimpedance Amplifier

    Science.gov (United States)

    Chapsky, Jacob

    2009-01-01

    The widest available operational amplifier, with the best voltage and current noise characteristics, is considered for transimpedance amplifier (TIA) applications where wide bandwidth is required to handle fast rising input signals (as for time-of-flight measurement cases). The added amplifier inside the TIA feedback loop can be configured to have slightly lower voltage gain than the bandwidth reduction factor.

  3. A highly scalable massively parallel fast marching method for the Eikonal equation

    Science.gov (United States)

    Yang, Jianming; Stern, Frederick

    2017-03-01

    The fast marching method is a widely used numerical method for solving the Eikonal equation arising from a variety of scientific and engineering fields. It is long deemed inherently sequential and an efficient parallel algorithm applicable to large-scale practical applications is not available in the literature. In this study, we present a highly scalable massively parallel implementation of the fast marching method using a domain decomposition approach. Central to this algorithm is a novel restarted narrow band approach that coordinates the frequency of communications and the amount of computations extra to a sequential run for achieving an unprecedented parallel performance. Within each restart, the narrow band fast marching method is executed; simple synchronous local exchanges and global reductions are adopted for communicating updated data in the overlapping regions between neighboring subdomains and getting the latest front status, respectively. The independence of front characteristics is exploited through special data structures and augmented status tags to extract the masked parallelism within the fast marching method. The efficiency, flexibility, and applicability of the parallel algorithm are demonstrated through several examples. These problems are extensively tested on six grids with up to 1 billion points using different numbers of processes ranging from 1 to 65536. Remarkable parallel speedups are achieved using tens of thousands of processes. Detailed pseudo-codes for both the sequential and parallel algorithms are provided to illustrate the simplicity of the parallel implementation and its similarity to the sequential narrow band fast marching algorithm.

  4. High performance parallel computers for science: New developments at the Fermilab advanced computer program

    International Nuclear Information System (INIS)

    Nash, T.; Areti, H.; Atac, R.

    1988-08-01

    Fermilab's Advanced Computer Program (ACP) has been developing highly cost effective, yet practical, parallel computers for high energy physics since 1984. The ACP's latest developments are proceeding in two directions. A Second Generation ACP Multiprocessor System for experiments will include $3500 RISC processors each with performance over 15 VAX MIPS. To support such high performance, the new system allows parallel I/O, parallel interprocess communication, and parallel host processes. The ACP Multi-Array Processor, has been developed for theoretical physics. Each $4000 node is a FORTRAN or C programmable pipelined 20 MFlops (peak), 10 MByte single board computer. These are plugged into a 16 port crossbar switch crate which handles both inter and intra crate communication. The crates are connected in a hypercube. Site oriented applications like lattice gauge theory are supported by system software called CANOPY, which makes the hardware virtually transparent to users. A 256 node, 5 GFlop, system is under construction. 10 refs., 7 figs

  5. 10th International Workshop on Parallel Tools for High Performance Computing

    CERN Document Server

    Gracia, José; Hilbrich, Tobias; Knüpfer, Andreas; Resch, Michael; Nagel, Wolfgang

    2017-01-01

    This book presents the proceedings of the 10th International Parallel Tools Workshop, held October 4-5, 2016 in Stuttgart, Germany – a forum to discuss the latest advances in parallel tools. High-performance computing plays an increasingly important role for numerical simulation and modelling in academic and industrial research. At the same time, using large-scale parallel systems efficiently is becoming more difficult. A number of tools addressing parallel program development and analysis have emerged from the high-performance computing community over the last decade, and what may have started as collection of small helper script has now matured to production-grade frameworks. Powerful user interfaces and an extensive body of documentation allow easy usage by non-specialists.

  6. Design of 2.5 GHz broad bandwidth microwave bandpass filter at operating frequency of 10 GHz using HFSS

    Science.gov (United States)

    Jasim, S. E.; Jusoh, M. A.; Mahmud, S. N. S.; Zamani, A. H.

    2018-04-01

    Development of low losses, small size and broad bandwidth microwave bandpass filter operating at higher frequencies is an active area of research. This paper presents a new route used to design and simulate microwave bandpass filter using finite element modelling and realized broad bandwidth, low losses, small dimension microwave bandpass filter operating at 10 GHz frequency using return loss method. The filter circuit has been carried out using Computer Aid Design (CAD), Ansoft HFSS software and designed with four parallel couple line model and small dimension (10 × 10 mm2) using LaAlO3 substrate. The response of the microwave filter circuit showed high return loss -50 dB at operating frequency at 10.4 GHz and broad bandwidth of 2.5 GHz from 9.5 to 12 GHz. The results indicate the filter design and simulation using HFSS is reliable and have the opportunity to transfer from lab potential experiments to the industry.

  7. High-speed detection of emergent market clustering via an unsupervised parallel genetic algorithm

    Directory of Open Access Journals (Sweden)

    Dieter Hendricks

    2016-02-01

    Full Text Available We implement a master-slave parallel genetic algorithm with a bespoke log-likelihood fitness function to identify emergent clusters within price evolutions. We use graphics processing units (GPUs to implement a parallel genetic algorithm and visualise the results using disjoint minimal spanning trees. We demonstrate that our GPU parallel genetic algorithm, implemented on a commercially available general purpose GPU, is able to recover stock clusters in sub-second speed, based on a subset of stocks in the South African market. This approach represents a pragmatic choice for low-cost, scalable parallel computing and is significantly faster than a prototype serial implementation in an optimised C-based fourth-generation programming language, although the results are not directly comparable because of compiler differences. Combined with fast online intraday correlation matrix estimation from high frequency data for cluster identification, the proposed implementation offers cost-effective, near-real-time risk assessment for financial practitioners.

  8. Modular high-temperature gas-cooled reactor simulation using parallel processors

    International Nuclear Information System (INIS)

    Ball, S.J.; Conklin, J.C.

    1989-01-01

    The MHPP (Modular HTGR Parallel Processor) code has been developed to simulate modular high-temperature gas-cooled reactor (MHTGR) transients and accidents. MHPP incorporates a very detailed model for predicting the dynamics of the reactor core, vessel, and cooling systems over a wide variety of scenarios ranging from expected transients to very-low-probability severe accidents. The simulations routines, which had originally been developed entirely as serial code, were readily adapted to parallel processing Fortran. The resulting parallelized simulation speed was enhanced significantly. Workstation interfaces are being developed to provide for user (operator) interaction. In this paper the benefits realized by adapting previous MHTGR codes to run on a parallel processor are discussed, along with results of typical accident analyses

  9. Note: Expanding the bandwidth of the ultra-low current amplifier using an artificial negative capacitor.

    Science.gov (United States)

    Xie, Kai; Liu, Yan; Li, XiaoPing; Guo, Lixin; Zhang, Hanlu

    2016-04-01

    The bandwidth and low noise characteristics are often contradictory in ultra-low current amplifier, because an inevitable parasitic capacitance is paralleled with the high value feedback resistor. In order to expand the amplifier's bandwidth, a novel approach was proposed by introducing an artificial negative capacitor to cancel the parasitic capacitance. The theory of the negative capacitance and the performance of the improved amplifier circuit with the negative capacitor are presented in this manuscript. The test was conducted by modifying an ultra-low current amplifier with a trans-impedance gain of 50 GΩ. The results show that the maximum bandwidth was expanded from 18.7 Hz to 3.3 kHz with more than 150 times of increase when the parasitic capacitance (∼0.17 pF) was cancelled. Meanwhile, the rise time decreased from 18.7 ms to 0.26 ms with no overshot. Any desired bandwidth or rise time within these ranges can be obtained by adjusting the ratio of cancellation of the parasitic and negative capacitance. This approach is especially suitable for the demand of rapid response to weak current, such as transient ion-beam detector, mass spectrometry analysis, and fast scanning microscope.

  10. Note: Expanding the bandwidth of the ultra-low current amplifier using an artificial negative capacitor

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Kai, E-mail: kaixie@mail.xidian.edu.cn; Liu, Yan; Li, XiaoPing [School of Aerospace Science and Technology, Xidian University, Xi’an 710071 (China); Guo, Lixin [School of Physics and Optoelectronic Engineering, Xidian University, Xi’an 710071 (China); Zhang, Hanlu [School of Communication & Information Engineering, Xi’an University of Posts & Telecommunication, Xi’an 710121 (China)

    2016-04-15

    The bandwidth and low noise characteristics are often contradictory in ultra-low current amplifier, because an inevitable parasitic capacitance is paralleled with the high value feedback resistor. In order to expand the amplifier’s bandwidth, a novel approach was proposed by introducing an artificial negative capacitor to cancel the parasitic capacitance. The theory of the negative capacitance and the performance of the improved amplifier circuit with the negative capacitor are presented in this manuscript. The test was conducted by modifying an ultra-low current amplifier with a trans-impedance gain of 50 GΩ. The results show that the maximum bandwidth was expanded from 18.7 Hz to 3.3 kHz with more than 150 times of increase when the parasitic capacitance (∼0.17 pF) was cancelled. Meanwhile, the rise time decreased from 18.7 ms to 0.26 ms with no overshot. Any desired bandwidth or rise time within these ranges can be obtained by adjusting the ratio of cancellation of the parasitic and negative capacitance. This approach is especially suitable for the demand of rapid response to weak current, such as transient ion-beam detector, mass spectrometry analysis, and fast scanning microscope.

  11. DVS-SOFTWARE: An Effective Tool for Applying Highly Parallelized Hardware To Computational Geophysics

    Science.gov (United States)

    Herrera, I.; Herrera, G. S.

    2015-12-01

    Most geophysical systems are macroscopic physical systems. The behavior prediction of such systems is carried out by means of computational models whose basic models are partial differential equations (PDEs) [1]. Due to the enormous size of the discretized version of such PDEs it is necessary to apply highly parallelized super-computers. For them, at present, the most efficient software is based on non-overlapping domain decomposition methods (DDM). However, a limiting feature of the present state-of-the-art techniques is due to the kind of discretizations used in them. Recently, I. Herrera and co-workers using 'non-overlapping discretizations' have produced the DVS-Software which overcomes this limitation [2]. The DVS-software can be applied to a great variety of geophysical problems and achieves very high parallel efficiencies (90%, or so [3]). It is therefore very suitable for effectively applying the most advanced parallel supercomputers available at present. In a parallel talk, in this AGU Fall Meeting, Graciela Herrera Z. will present how this software is being applied to advance MOD-FLOW. Key Words: Parallel Software for Geophysics, High Performance Computing, HPC, Parallel Computing, Domain Decomposition Methods (DDM)REFERENCES [1]. Herrera Ismael and George F. Pinder, Mathematical Modelling in Science and Engineering: An axiomatic approach", John Wiley, 243p., 2012. [2]. Herrera, I., de la Cruz L.M. and Rosas-Medina A. "Non Overlapping Discretization Methods for Partial, Differential Equations". NUMER METH PART D E, 30: 1427-1454, 2014, DOI 10.1002/num 21852. (Open source) [3]. Herrera, I., & Contreras Iván "An Innovative Tool for Effectively Applying Highly Parallelized Software To Problems of Elasticity". Geofísica Internacional, 2015 (In press)

  12. High performance statistical computing with parallel R: applications to biology and climate modelling

    International Nuclear Information System (INIS)

    Samatova, Nagiza F; Branstetter, Marcia; Ganguly, Auroop R; Hettich, Robert; Khan, Shiraj; Kora, Guruprasad; Li, Jiangtian; Ma, Xiaosong; Pan, Chongle; Shoshani, Arie; Yoginath, Srikanth

    2006-01-01

    Ultrascale computing and high-throughput experimental technologies have enabled the production of scientific data about complex natural phenomena. With this opportunity, comes a new problem - the massive quantities of data so produced. Answers to fundamental questions about the nature of those phenomena remain largely hidden in the produced data. The goal of this work is to provide a scalable high performance statistical data analysis framework to help scientists perform interactive analyses of these raw data to extract knowledge. Towards this goal we have been developing an open source parallel statistical analysis package, called Parallel R, that lets scientists employ a wide range of statistical analysis routines on high performance shared and distributed memory architectures without having to deal with the intricacies of parallelizing these routines

  13. Design of the Trap Filter for the High Power Converters with Parallel Interleaved VSCs

    DEFF Research Database (Denmark)

    Gohil, Ghanshyamsinh Vijaysinh; Bede, Lorand; Teodorescu, Remus

    2014-01-01

    The power handling capability of the state-of-the-art semiconductor devices is limited. Therefore, the Voltage Source Converters (VSCs) are often connected in parallel to realize high power converter. The switching frequency semiconductor devices, used in the high power VSCs, is also limited...

  14. 7th International Workshop on Parallel Tools for High Performance Computing

    CERN Document Server

    Gracia, José; Nagel, Wolfgang; Resch, Michael

    2014-01-01

    Current advances in High Performance Computing (HPC) increasingly impact efficient software development workflows. Programmers for HPC applications need to consider trends such as increased core counts, multiple levels of parallelism, reduced memory per core, and I/O system challenges in order to derive well performing and highly scalable codes. At the same time, the increasing complexity adds further sources of program defects. While novel programming paradigms and advanced system libraries provide solutions for some of these challenges, appropriate supporting tools are indispensable. Such tools aid application developers in debugging, performance analysis, or code optimization and therefore make a major contribution to the development of robust and efficient parallel software. This book introduces a selection of the tools presented and discussed at the 7th International Parallel Tools Workshop, held in Dresden, Germany, September 3-4, 2013.  

  15. 8th International Workshop on Parallel Tools for High Performance Computing

    CERN Document Server

    Gracia, José; Knüpfer, Andreas; Resch, Michael; Nagel, Wolfgang

    2015-01-01

    Numerical simulation and modelling using High Performance Computing has evolved into an established technique in academic and industrial research. At the same time, the High Performance Computing infrastructure is becoming ever more complex. For instance, most of the current top systems around the world use thousands of nodes in which classical CPUs are combined with accelerator cards in order to enhance their compute power and energy efficiency. This complexity can only be mastered with adequate development and optimization tools. Key topics addressed by these tools include parallelization on heterogeneous systems, performance optimization for CPUs and accelerators, debugging of increasingly complex scientific applications, and optimization of energy usage in the spirit of green IT. This book represents the proceedings of the 8th International Parallel Tools Workshop, held October 1-2, 2014 in Stuttgart, Germany – which is a forum to discuss the latest advancements in the parallel tools.

  16. Physically Connected Stacked Patch Antenna Design with 100% Bandwidth

    KAUST Repository

    Klionovski, Kirill; Shamim, Atif

    2017-01-01

    Typically, stacked patch antennas are parasitically coupled and provide larger bandwidth than a single patch antenna. Here, we show a stacked patch antenna design where square patches with semi-circular cutouts are physically connected to each other. This arrangement provides 100% bandwidth from 23.9–72.2 GHz with consistent high gain (5 dBi or more) across the entire bandwidth. In another variation, a single patch loaded with a superstrate provides 83.5% bandwidth from 25.6–62.3 GHz. The mechanism of bandwidth enhancement is explained through electromagnetic simulations. Measured reflection coefficient, radiation patterns and gain results confirm the extremely wideband performance of the design.

  17. Physically Connected Stacked Patch Antenna Design with 100% Bandwidth

    KAUST Repository

    Klionovski, Kirill

    2017-11-01

    Typically, stacked patch antennas are parasitically coupled and provide larger bandwidth than a single patch antenna. Here, we show a stacked patch antenna design where square patches with semi-circular cutouts are physically connected to each other. This arrangement provides 100% bandwidth from 23.9–72.2 GHz with consistent high gain (5 dBi or more) across the entire bandwidth. In another variation, a single patch loaded with a superstrate provides 83.5% bandwidth from 25.6–62.3 GHz. The mechanism of bandwidth enhancement is explained through electromagnetic simulations. Measured reflection coefficient, radiation patterns and gain results confirm the extremely wideband performance of the design.

  18. Bandwidth tunable amplifier for recording biopotential signals.

    Science.gov (United States)

    Hwang, Sungkil; Aninakwa, Kofi; Sonkusale, Sameer

    2010-01-01

    This paper presents a low noise, low power, bandwidth tunable amplifier for bio-potential signal recording applications. By employing depletion-mode pMOS transistor in diode configuration as a tunable sub pA current source to adjust the resistivity of MOS-Bipolar pseudo-resistor, the bandwidth is adjusted without any need for a separate band-pass filter stage. For high CMRR, PSRR and dynamic range, a fully differential structure is used in the design of the amplifier. The amplifier achieves a midband gain of 39.8dB with a tunable high-pass cutoff frequency ranging from 0.1Hz to 300Hz. The amplifier is fabricated in 0.18εm CMOS process and occupies 0.14mm(2) of chip area. A three electrode ECG measurement is performed using the proposed amplifier to show its feasibility for low power, compact wearable ECG monitoring application.

  19. Line filter design of parallel interleaved VSCs for high power wind energy conversion systems

    DEFF Research Database (Denmark)

    Gohil, Ghanshyamsinh Vijaysinh; Bede, Lorand; Teodorescu, Remus

    2015-01-01

    The Voltage Source Converters (VSCs) are often connected in parallel in a Wind Energy Conversion System (WECS) to match the high power rating of the modern wind turbines. The effect of the interleaved carriers on the harmonic performance of the parallel connected VSCs is analyzed in this paper...... limit. In order to achieve the desired filter performance with optimal values of the filter parameters, the use of a LC trap branch with the conventional LCL filter is proposed. The expressions for the resonant frequencies of the proposed line filter are derived and used in the design to selectively...

  20. High performance parallelism pearls 2 multicore and many-core programming approaches

    CERN Document Server

    Jeffers, Jim

    2015-01-01

    High Performance Parallelism Pearls Volume 2 offers another set of examples that demonstrate how to leverage parallelism. Similar to Volume 1, the techniques included here explain how to use processors and coprocessors with the same programming - illustrating the most effective ways to combine Xeon Phi coprocessors with Xeon and other multicore processors. The book includes examples of successful programming efforts, drawn from across industries and domains such as biomed, genetics, finance, manufacturing, imaging, and more. Each chapter in this edited work includes detailed explanations of t

  1. A digital calibration technique for an ultra high-speed wide-bandwidth folding and interpolating analog-to-digital converter in 0.18-{mu}m CMOS technology

    Energy Technology Data Exchange (ETDEWEB)

    Yu Jinshan; Zhang Ruitao; Zhang Zhengping; Wang Yonglu; Zhu Can; Zhang Lei; Yu Zhou; Han Yong, E-mail: yujinshan@yeah.net [National Laboratory of Analog IC' s, Chongqing 400060 (China)

    2011-01-15

    A digital calibration technique for an ultra high-speed folding and interpolating analog-to-digital converter in 0.18-{mu}m CMOS technology is presented. The similar digital calibration techniques are taken for high 3-bit flash converter and low 5-bit folding and interpolating converter, which are based on well-designed calibration reference, calibration DAC and comparators. The spice simulation and the measured results show the ADC produces 5.9 ENOB with calibration disabled and 7.2 ENOB with calibration enabled for high-frequency wide-bandwidth analog input. (semiconductor integrated circuits)

  2. Polybinary modulation for bandwidth limited optical links

    DEFF Research Database (Denmark)

    Vegas Olmos, Juan José; Jurado-Navas, Antonio

    2015-01-01

    form of partial response modulation, employs simple codification and filtering at the transmitter to drastically increase the spectral efficiency. At the receiver side, poly binary modulation requires low complexity direct detection and very little digital signal processing. This talk will review...... the recent results on poly binary modulation, comprising both binary and multilevel signals as seed signals. The results will show how poly binary modulation effectively reduces the bandwidth requirements on optical links while providing high spectral efficiency....

  3. Load balancing in highly parallel processing of Monte Carlo code for particle transport

    International Nuclear Information System (INIS)

    Higuchi, Kenji; Takemiya, Hiroshi; Kawasaki, Takuji

    1998-01-01

    In parallel processing of Monte Carlo (MC) codes for neutron, photon and electron transport problems, particle histories are assigned to processors making use of independency of the calculation for each particle. Although we can easily parallelize main part of a MC code by this method, it is necessary and practically difficult to optimize the code concerning load balancing in order to attain high speedup ratio in highly parallel processing. In fact, the speedup ratio in the case of 128 processors remains in nearly one hundred times when using the test bed for the performance evaluation. Through the parallel processing of the MCNP code, which is widely used in the nuclear field, it is shown that it is difficult to attain high performance by static load balancing in especially neutron transport problems, and a load balancing method, which dynamically changes the number of assigned particles minimizing the sum of the computational and communication costs, overcomes the difficulty, resulting in nearly fifteen percentage of reduction for execution time. (author)

  4. Highly accelerated cardiac cine parallel MRI using low-rank matrix completion and partial separability model

    Science.gov (United States)

    Lyu, Jingyuan; Nakarmi, Ukash; Zhang, Chaoyi; Ying, Leslie

    2016-05-01

    This paper presents a new approach to highly accelerated dynamic parallel MRI using low rank matrix completion, partial separability (PS) model. In data acquisition, k-space data is moderately randomly undersampled at the center kspace navigator locations, but highly undersampled at the outer k-space for each temporal frame. In reconstruction, the navigator data is reconstructed from undersampled data using structured low-rank matrix completion. After all the unacquired navigator data is estimated, the partial separable model is used to obtain partial k-t data. Then the parallel imaging method is used to acquire the entire dynamic image series from highly undersampled data. The proposed method has shown to achieve high quality reconstructions with reduction factors up to 31, and temporal resolution of 29ms, when the conventional PS method fails.

  5. Parameters that affect parallel processing for computational electromagnetic simulation codes on high performance computing clusters

    Science.gov (United States)

    Moon, Hongsik

    What is the impact of multicore and associated advanced technologies on computational software for science? Most researchers and students have multicore laptops or desktops for their research and they need computing power to run computational software packages. Computing power was initially derived from Central Processing Unit (CPU) clock speed. That changed when increases in clock speed became constrained by power requirements. Chip manufacturers turned to multicore CPU architectures and associated technological advancements to create the CPUs for the future. Most software applications benefited by the increased computing power the same way that increases in clock speed helped applications run faster. However, for Computational ElectroMagnetics (CEM) software developers, this change was not an obvious benefit - it appeared to be a detriment. Developers were challenged to find a way to correctly utilize the advancements in hardware so that their codes could benefit. The solution was parallelization and this dissertation details the investigation to address these challenges. Prior to multicore CPUs, advanced computer technologies were compared with the performance using benchmark software and the metric was FLoting-point Operations Per Seconds (FLOPS) which indicates system performance for scientific applications that make heavy use of floating-point calculations. Is FLOPS an effective metric for parallelized CEM simulation tools on new multicore system? Parallel CEM software needs to be benchmarked not only by FLOPS but also by the performance of other parameters related to type and utilization of the hardware, such as CPU, Random Access Memory (RAM), hard disk, network, etc. The codes need to be optimized for more than just FLOPs and new parameters must be included in benchmarking. In this dissertation, the parallel CEM software named High Order Basis Based Integral Equation Solver (HOBBIES) is introduced. This code was developed to address the needs of the

  6. Large bandwidth RGC transimpedance preamplifier design in SCA

    International Nuclear Information System (INIS)

    Wang Ke; Wang Zheng; Liu Zhen'an; Wei Wei; Lu Weiguo; Gary Varner

    2009-01-01

    A Large Bandwidth RGC Transimpedance Preamplifier is designed for amplifying the high-fidelity timing signal in Switch Capacitance Array chip application. This amplifier have characteristics of low input impedance, large bandwidth, high transimpedance. It will be made under TSMC 0.25μm CMOS technology, and the supply voltage is single 2.5 V. Simulation results indicate: the transimpedance is 5000 ohm, -3dB BW is 953 MHz, and the detector output capacitance have litter effect on the bandwidth in some range. (authors)

  7. Time-optimal control with finite bandwidth

    Science.gov (United States)

    Hirose, M.; Cappellaro, P.

    2018-04-01

    Time-optimal control theory provides recipes to achieve quantum operations with high fidelity and speed, as required in quantum technologies such as quantum sensing and computation. While technical advances have achieved the ultrastrong driving regime in many physical systems, these capabilities have yet to be fully exploited for the precise control of quantum systems, as other limitations, such as the generation of higher harmonics or the finite response time of the control apparatus, prevent the implementation of theoretical time-optimal control. Here we present a method to achieve time-optimal control of qubit systems that can take advantage of fast driving beyond the rotating wave approximation. We exploit results from time-optimal control theory to design driving protocols that can be implemented with realistic, finite-bandwidth control fields, and we find a relationship between bandwidth limitations and achievable control fidelity.

  8. CUDA/GPU Technology : Parallel Programming For High Performance Scientific Computing

    OpenAIRE

    YUHENDRA; KUZE, Hiroaki; JOSAPHAT, Tetuko Sri Sumantyo

    2009-01-01

    [ABSTRACT]Graphics processing units (GP Us) originally designed for computer video cards have emerged as the most powerful chip in a high-performance workstation. In the high performance computation capabilities, graphic processing units (GPU) lead to much more powerful performance than conventional CPUs by means of parallel processing. In 2007, the birth of Compute Unified Device Architecture (CUDA) and CUDA-enabled GPUs by NVIDIA Corporation brought a revolution in the general purpose GPU a...

  9. Accelerated Electron-Beam Formation with a High Capture Coefficient in a Parallel Coupled Accelerating Structure

    Science.gov (United States)

    Chernousov, Yu. D.; Shebolaev, I. V.; Ikryanov, I. M.

    2018-01-01

    An electron beam with a high (close to 100%) coefficient of electron capture into the regime of acceleration has been obtained in a linear electron accelerator based on a parallel coupled slow-wave structure, electron gun with microwave-controlled injection current, and permanent-magnet beam-focusing system. The high capture coefficient was due to the properties of the accelerating structure, beam-focusing system, and electron-injection system. Main characteristics of the proposed systems are presented.

  10. The Protein Maker: an automated system for high-throughput parallel purification

    International Nuclear Information System (INIS)

    Smith, Eric R.; Begley, Darren W.; Anderson, Vanessa; Raymond, Amy C.; Haffner, Taryn E.; Robinson, John I.; Edwards, Thomas E.; Duncan, Natalie; Gerdts, Cory J.; Mixon, Mark B.; Nollert, Peter; Staker, Bart L.; Stewart, Lance J.

    2011-01-01

    The Protein Maker instrument addresses a critical bottleneck in structural genomics by allowing automated purification and buffer testing of multiple protein targets in parallel with a single instrument. Here, the use of this instrument to (i) purify multiple influenza-virus proteins in parallel for crystallization trials and (ii) identify optimal lysis-buffer conditions prior to large-scale protein purification is described. The Protein Maker is an automated purification system developed by Emerald BioSystems for high-throughput parallel purification of proteins and antibodies. This instrument allows multiple load, wash and elution buffers to be used in parallel along independent lines for up to 24 individual samples. To demonstrate its utility, its use in the purification of five recombinant PB2 C-terminal domains from various subtypes of the influenza A virus is described. Three of these constructs crystallized and one diffracted X-rays to sufficient resolution for structure determination and deposition in the Protein Data Bank. Methods for screening lysis buffers for a cytochrome P450 from a pathogenic fungus prior to upscaling expression and purification are also described. The Protein Maker has become a valuable asset within the Seattle Structural Genomics Center for Infectious Disease (SSGCID) and hence is a potentially valuable tool for a variety of high-throughput protein-purification applications

  11. Application of parallel connected power-MOSFET elements to high current d.c. power supply

    International Nuclear Information System (INIS)

    Matsukawa, Tatsuya; Shioyama, Masanori; Shimada, Katsuhiro; Takaku, Taku; Neumeyer, Charles; Tsuji-Iio, Shunji; Shimada, Ryuichi

    2001-01-01

    The low aspect ratio spherical torus (ST), which has single turn toroidal field coil, requires the extremely high d.c. current like as 20 MA to energize the coil. Considering the ratings of such extremely high current and low voltage, power-MOSFET element is employed as the switching device for the a.c./d.c. converter of power supply. One of the advantages of power-MOSFET element is low on-state resistance, which is to meet the high current and low voltage operation. Recently, the capacity of power-MOSFET element has been increased and its on-state resistance has been decreased, so that the possibility of construction of high current and low voltage a.c./d.c. converter with parallel connected power-MOSFET elements has been growing. With the aim of developing the high current d.c. power supply using power-MOSFET, the basic characteristics of parallel operation with power-MOSFET elements are experimentally investigated. And, the synchronous rectifier type and the bi-directional self commutated type a.c./d.c. converters using parallel connected power-MOSFET elements are proposed

  12. Reconstitution of Low Bandwidth Reaction History

    International Nuclear Information System (INIS)

    May, M.; Clancy, T.; Fittinghoff, D.; Gennaro, P.; Hagans, K.; Halvorson, G.; Lowry, M.; Perry, T.; Roberson, P.; Smith, D.; Teruya, A.; Blair, J.; Davis, B.; Hunt, E.; Emkeit, B.; Galbraith, J.; Kelly, B.; Montoya, R.; Nickel, G.; Ogle, J.; Wilson, K.; Wood, M.

    2004-01-01

    The goal of the Test Readiness Program is to transition to a 24 month test readiness posture and if approved move to an 18-month posture. One of the key components of the Test Readiness Program necessary to meet this goal is the reconstitution of the important diagnostics. Since the end of nuclear testing, the ability to field diagnostics on a nuclear test has deteriorated. Reconstitution of diagnostics before those who had experience in nuclear testing either retire or leave is essential to achieving a shorter test readiness posture. Also, the data recording systems have not been used since the end of testing. This report documents the reconstitution of one vital diagnostic: the low bandwidth reaction history diagnostic for FY04. Reaction history is one of the major diagnostics that has been used on all LLNL and LANL tests since the early days of nuclear testing. Reaction history refers to measuring the time history of the gamma and neutron output from a nuclear test. This gives direct information on the nuclear reactions taking place in the device. The reaction history measurements are one of the prime measurements the nuclear weapon scientists use to validate their models of device performance. All tests currently under consideration require the reaction history diagnostic. Thus moving to a shorter test readiness posture requires the reconstitution of the ability to make reaction history measurements. Reconstitution of reaction history was planned to be in two steps. Reaction history measurements that have been used in the past can be broadly placed into two categories. The most common type of reaction history and the one that has been performed on virtually all nuclear tests is termed low bandwidth reaction history. This measurement has a time response that is limited by the bandpass of kilometer length coaxial cables. When higher bandwidth has been required for specific measurements, fiber optic techniques have been used. This is referred to as high-bandwidth

  13. High-performance parallel approaches for three-dimensional light detection and ranging point clouds gridding

    Science.gov (United States)

    Rizki, Permata Nur Miftahur; Lee, Heezin; Lee, Minsu; Oh, Sangyoon

    2017-01-01

    With the rapid advance of remote sensing technology, the amount of three-dimensional point-cloud data has increased extraordinarily, requiring faster processing in the construction of digital elevation models. There have been several attempts to accelerate the computation using parallel methods; however, little attention has been given to investigating different approaches for selecting the most suited parallel programming model for a given computing environment. We present our findings and insights identified by implementing three popular high-performance parallel approaches (message passing interface, MapReduce, and GPGPU) on time demanding but accurate kriging interpolation. The performances of the approaches are compared by varying the size of the grid and input data. In our empirical experiment, we demonstrate the significant acceleration by all three approaches compared to a C-implemented sequential-processing method. In addition, we also discuss the pros and cons of each method in terms of usability, complexity infrastructure, and platform limitation to give readers a better understanding of utilizing those parallel approaches for gridding purposes.

  14. Full-field parallel interferometry coherence probe microscope for high-speed optical metrology.

    Science.gov (United States)

    Safrani, A; Abdulhalim, I

    2015-06-01

    Parallel detection of several achromatic phase-shifted images is used to obtain a high-speed, high-resolution, full-field, optical coherence probe tomography system based on polarization interferometry. The high enface imaging speed, short coherence gate, and high lateral resolution provided by the system are exploited to determine microbump height uniformity in an integrated semiconductor chip at 50 frames per second. The technique is demonstrated using the Linnik microscope, although it can be implemented on any polarization-based interference microscopy system.

  15. Parallel Gene Expression Differences between Low and High Latitude Populations of Drosophila melanogaster and D. simulans.

    Science.gov (United States)

    Zhao, Li; Wit, Janneke; Svetec, Nicolas; Begun, David J

    2015-05-01

    Gene expression variation within species is relatively common, however, the role of natural selection in the maintenance of this variation is poorly understood. Here we investigate low and high latitude populations of Drosophila melanogaster and its sister species, D. simulans, to determine whether the two species show similar patterns of population differentiation, consistent with a role for spatially varying selection in maintaining gene expression variation. We compared at two temperatures the whole male transcriptome of D. melanogaster and D. simulans sampled from Panama City (Panama) and Maine (USA). We observed a significant excess of genes exhibiting differential expression in both species, consistent with parallel adaptation to heterogeneous environments. Moreover, the majority of genes showing parallel expression differentiation showed the same direction of differential expression in the two species and the magnitudes of expression differences between high and low latitude populations were correlated across species, further bolstering the conclusion that parallelism for expression phenotypes results from spatially varying selection. However, the species also exhibited important differences in expression phenotypes. For example, the genomic extent of genotype × environment interaction was much more common in D. melanogaster. Highly differentiated SNPs between low and high latitudes were enriched in the 3' UTRs and CDS of the geographically differently expressed genes in both species, consistent with an important role for cis-acting variants in driving local adaptation for expression-related phenotypes.

  16. Evaluation of the power consumption of a high-speed parallel robot

    Science.gov (United States)

    Han, Gang; Xie, Fugui; Liu, Xin-Jun

    2018-06-01

    An inverse dynamic model of a high-speed parallel robot is established based on the virtual work principle. With this dynamic model, a new evaluation method is proposed to measure the power consumption of the robot during pick-and-place tasks. The power vector is extended in this method and used to represent the collinear velocity and acceleration of the moving platform. Afterward, several dynamic performance indices, which are homogenous and possess obvious physical meanings, are proposed. These indices can evaluate the power input and output transmissibility of the robot in a workspace. The distributions of the power input and output transmissibility of the high-speed parallel robot are derived with these indices and clearly illustrated in atlases. Furtherly, a low-power-consumption workspace is selected for the robot.

  17. Intelligent trigger by massively parallel processors for high energy physics experiments

    International Nuclear Information System (INIS)

    Rohrbach, F.; Vesztergombi, G.

    1992-01-01

    The CERN-MPPC collaboration concentrates its effort on the development of machines based on massive parallelism with thousands of integrated processing elements, arranged in a string. Seven applications are under detailed studies within the collaboration: three for LHC, one for SSC, two for fixed target high energy physics at CERN and one for HDTV. Preliminary results are presented. They show that the objectives should be reached with the use of the ASP architecture. (author)

  18. Decision Optimization for Power Grid Operating Conditions with High- and Low-Voltage Parallel Loops

    Directory of Open Access Journals (Sweden)

    Dong Yang

    2017-05-01

    Full Text Available With the development of higher-voltage power grids, the high- and low-voltage parallel loops are emerging, which lead to energy losses and even threaten the security and stability of power systems. The multi-infeed high-voltage direct current (HVDC configurations widely appearing in AC/DC interconnected power systems make this situation even worse. Aimed at energy saving and system security, a decision optimization method for power grid operating conditions with high- and low-voltage parallel loops is proposed in this paper. Firstly, considering hub substation distribution and power grid structure, parallel loop opening schemes are generated with GN (Girvan-Newman algorithms. Then, candidate opening schemes are preliminarily selected from all these generated schemes based on a filtering index. Finally, with the influence on power system security, stability and operation economy in consideration, an evaluation model for candidate opening schemes is founded based on analytic hierarchy process (AHP. And a fuzzy evaluation algorithm is used to find the optimal scheme. Simulation results of a New England 39-bus system and an actual power system validate the effectiveness and superiority of this proposed method.

  19. Java parallel secure stream for grid computing

    International Nuclear Information System (INIS)

    Chen, J.; Akers, W.; Chen, Y.; Watson, W.

    2001-01-01

    The emergence of high speed wide area networks makes grid computing a reality. However grid applications that need reliable data transfer still have difficulties to achieve optimal TCP performance due to network tuning of TCP window size to improve the bandwidth and to reduce latency on a high speed wide area network. The authors present a pure Java package called JPARSS (Java Parallel Secure Stream) that divides data into partitions that are sent over several parallel Java streams simultaneously and allows Java or Web applications to achieve optimal TCP performance in a gird environment without the necessity of tuning the TCP window size. Several experimental results are provided to show that using parallel stream is more effective than tuning TCP window size. In addition X.509 certificate based single sign-on mechanism and SSL based connection establishment are integrated into this package. Finally a few applications using this package will be discussed

  20. Comparative Study on  Paralleled vs. Scaled Dc-dc Converters  in High Voltage Gain Applications

    DEFF Research Database (Denmark)

    Klimczak, Pawel; Munk-Nielsen, Stig

    2008-01-01

    Today power converters are present in many commercial, medical and industrial applications. A lot of them are high power and high current applications. In order to increase power handling capability several transistors or diodes are paralleled often. However such paralleling may lead to converter...

  1. A parallel input composite transimpedance amplifier

    Science.gov (United States)

    Kim, D. J.; Kim, C.

    2018-01-01

    A new approach to high performance current to voltage preamplifier design is presented. The design using multiple operational amplifiers (op-amps) has a parasitic capacitance compensation network and a composite amplifier topology for fast, precision, and low noise performance. The input stage consisting of a parallel linked JFET op-amps and a high-speed bipolar junction transistor (BJT) gain stage driving the output in the composite amplifier topology, cooperating with the capacitance compensation feedback network, ensures wide bandwidth stability in the presence of input capacitance above 40 nF. The design is ideal for any two-probe measurement, including high impedance transport and scanning tunneling microscopy measurements.

  2. Parallel optical control of spatiotemporal neuronal spike activity using high-frequency digital light processingtechnology

    Directory of Open Access Journals (Sweden)

    Jason eJerome

    2011-08-01

    Full Text Available Neurons in the mammalian neocortex receive inputs from and communicate back to thousands of other neurons, creating complex spatiotemporal activity patterns. The experimental investigation of these parallel dynamic interactions has been limited due to the technical challenges of monitoring or manipulating neuronal activity at that level of complexity. Here we describe a new massively parallel photostimulation system that can be used to control action potential firing in in vitro brain slices with high spatial and temporal resolution while performing extracellular or intracellular electrophysiological measurements. The system uses Digital-Light-Processing (DLP technology to generate 2-dimensional (2D stimulus patterns with >780,000 independently controlled photostimulation sites that operate at high spatial (5.4 µm and temporal (>13kHz resolution. Light is projected through the quartz-glass bottom of the perfusion chamber providing access to a large area (2.76 x 2.07 mm2 of the slice preparation. This system has the unique capability to induce temporally precise action potential firing in large groups of neurons distributed over a wide area covering several cortical columns. Parallel photostimulation opens up new opportunities for the in vitro experimental investigation of spatiotemporal neuronal interactions at a broad range of anatomical scales.

  3. Kemari: A Portable High Performance Fortran System for Distributed Memory Parallel Processors

    Directory of Open Access Journals (Sweden)

    T. Kamachi

    1997-01-01

    Full Text Available We have developed a compilation system which extends High Performance Fortran (HPF in various aspects. We support the parallelization of well-structured problems with loop distribution and alignment directives similar to HPF's data distribution directives. Such directives give both additional control to the user and simplify the compilation process. For the support of unstructured problems, we provide directives for dynamic data distribution through user-defined mappings. The compiler also allows integration of message-passing interface (MPI primitives. The system is part of a complete programming environment which also comprises a parallel debugger and a performance monitor and analyzer. After an overview of the compiler, we describe the language extensions and related compilation mechanisms in detail. Performance measurements demonstrate the compiler's applicability to a variety of application classes.

  4. Enabling Requirements-Based Programming for Highly-Dependable Complex Parallel and Distributed Systems

    Science.gov (United States)

    Hinchey, Michael G.; Rash, James L.; Rouff, Christopher A.

    2005-01-01

    The manual application of formal methods in system specification has produced successes, but in the end, despite any claims and assertions by practitioners, there is no provable relationship between a manually derived system specification or formal model and the customer's original requirements. Complex parallel and distributed system present the worst case implications for today s dearth of viable approaches for achieving system dependability. No avenue other than formal methods constitutes a serious contender for resolving the problem, and so recognition of requirements-based programming has come at a critical juncture. We describe a new, NASA-developed automated requirement-based programming method that can be applied to certain classes of systems, including complex parallel and distributed systems, to achieve a high degree of dependability.

  5. Efficient high-precision matrix algebra on parallel architectures for nonlinear combinatorial optimization

    KAUST Repository

    Gunnels, John; Lee, Jon; Margulies, Susan

    2010-01-01

    We provide a first demonstration of the idea that matrix-based algorithms for nonlinear combinatorial optimization problems can be efficiently implemented. Such algorithms were mainly conceived by theoretical computer scientists for proving efficiency. We are able to demonstrate the practicality of our approach by developing an implementation on a massively parallel architecture, and exploiting scalable and efficient parallel implementations of algorithms for ultra high-precision linear algebra. Additionally, we have delineated and implemented the necessary algorithmic and coding changes required in order to address problems several orders of magnitude larger, dealing with the limits of scalability from memory footprint, computational efficiency, reliability, and interconnect perspectives. © Springer and Mathematical Programming Society 2010.

  6. Efficient high-precision matrix algebra on parallel architectures for nonlinear combinatorial optimization

    KAUST Repository

    Gunnels, John

    2010-06-01

    We provide a first demonstration of the idea that matrix-based algorithms for nonlinear combinatorial optimization problems can be efficiently implemented. Such algorithms were mainly conceived by theoretical computer scientists for proving efficiency. We are able to demonstrate the practicality of our approach by developing an implementation on a massively parallel architecture, and exploiting scalable and efficient parallel implementations of algorithms for ultra high-precision linear algebra. Additionally, we have delineated and implemented the necessary algorithmic and coding changes required in order to address problems several orders of magnitude larger, dealing with the limits of scalability from memory footprint, computational efficiency, reliability, and interconnect perspectives. © Springer and Mathematical Programming Society 2010.

  7. 9th International Workshop on Parallel Tools for High Performance Computing

    CERN Document Server

    Hilbrich, Tobias; Niethammer, Christoph; Gracia, José; Nagel, Wolfgang; Resch, Michael

    2016-01-01

    High Performance Computing (HPC) remains a driver that offers huge potentials and benefits for science and society. However, a profound understanding of the computational matters and specialized software is needed to arrive at effective and efficient simulations. Dedicated software tools are important parts of the HPC software landscape, and support application developers. Even though a tool is by definition not a part of an application, but rather a supplemental piece of software, it can make a fundamental difference during the development of an application. Such tools aid application developers in the context of debugging, performance analysis, and code optimization, and therefore make a major contribution to the development of robust and efficient parallel software. This book introduces a selection of the tools presented and discussed at the 9th International Parallel Tools Workshop held in Dresden, Germany, September 2-3, 2015, which offered an established forum for discussing the latest advances in paral...

  8. Computational Performance of a Parallelized Three-Dimensional High-Order Spectral Element Toolbox

    Science.gov (United States)

    Bosshard, Christoph; Bouffanais, Roland; Clémençon, Christian; Deville, Michel O.; Fiétier, Nicolas; Gruber, Ralf; Kehtari, Sohrab; Keller, Vincent; Latt, Jonas

    In this paper, a comprehensive performance review of an MPI-based high-order three-dimensional spectral element method C++ toolbox is presented. The focus is put on the performance evaluation of several aspects with a particular emphasis on the parallel efficiency. The performance evaluation is analyzed with help of a time prediction model based on a parameterization of the application and the hardware resources. A tailor-made CFD computation benchmark case is introduced and used to carry out this review, stressing the particular interest for clusters with up to 8192 cores. Some problems in the parallel implementation have been detected and corrected. The theoretical complexities with respect to the number of elements, to the polynomial degree, and to communication needs are correctly reproduced. It is concluded that this type of code has a nearly perfect speed up on machines with thousands of cores, and is ready to make the step to next-generation petaflop machines.

  9. Applications of Emerging Parallel Optical Link Technology to High Energy Physics Experiments

    International Nuclear Information System (INIS)

    Chramowicz, J.; Kwan, S.; Prosser, A.; Winchell, M.

    2011-01-01

    Modern particle detectors depend upon optical fiber links to deliver event data to upstream trigger and data processing systems. Future detector systems can benefit from the development of dense arrangements of high speed optical links emerging from the telecommunications and storage area network market segments. These links support data transfers in each direction at rates up to 120 Gbps in packages that minimize or even eliminate edge connector requirements. Emerging products include a class of devices known as optical engines which permit assembly of the optical transceivers in close proximity to the electrical interfaces of ASICs and FPGAs which handle the data in parallel electrical format. Such assemblies will reduce required printed circuit board area and minimize electromagnetic interference and susceptibility. We will present test results of some of these parallel components and report on the development of pluggable FPGA Mezzanine Cards equipped with optical engines to provide to collaborators on the Versatile Link Common Project for the HI-LHC at CERN.

  10. Data analysis-based autonomic bandwidth adjustment in software defined multi-vendor optical transport networks.

    Science.gov (United States)

    Li, Yajie; Zhao, Yongli; Zhang, Jie; Yu, Xiaosong; Jing, Ruiquan

    2017-11-27

    Network operators generally provide dedicated lightpaths for customers to meet the demand for high-quality transmission. Considering the variation of traffic load, customers usually rent peak bandwidth that exceeds the practical average traffic requirement. In this case, bandwidth provisioning is unmetered and customers have to pay according to peak bandwidth. Supposing that network operators could keep track of traffic load and allocate bandwidth dynamically, bandwidth can be provided as a metered service and customers would pay for the bandwidth that they actually use. To achieve cost-effective bandwidth provisioning, this paper proposes an autonomic bandwidth adjustment scheme based on data analysis of traffic load. The scheme is implemented in a software defined networking (SDN) controller and is demonstrated in the field trial of multi-vendor optical transport networks. The field trial shows that the proposed scheme can track traffic load and realize autonomic bandwidth adjustment. In addition, a simulation experiment is conducted to evaluate the performance of the proposed scheme. We also investigate the impact of different parameters on autonomic bandwidth adjustment. Simulation results show that the step size and adjustment period have significant influences on bandwidth savings and packet loss. A small value of step size and adjustment period can bring more benefits by tracking traffic variation with high accuracy. For network operators, the scheme can serve as technical support of realizing bandwidth as metered service in the future.

  11. High performance parallel computing of flows in complex geometries: I. Methods

    International Nuclear Information System (INIS)

    Gourdain, N; Gicquel, L; Montagnac, M; Vermorel, O; Staffelbach, G; Garcia, M; Boussuge, J-F; Gazaix, M; Poinsot, T

    2009-01-01

    Efficient numerical tools coupled with high-performance computers, have become a key element of the design process in the fields of energy supply and transportation. However flow phenomena that occur in complex systems such as gas turbines and aircrafts are still not understood mainly because of the models that are needed. In fact, most computational fluid dynamics (CFD) predictions as found today in industry focus on a reduced or simplified version of the real system (such as a periodic sector) and are usually solved with a steady-state assumption. This paper shows how to overcome such barriers and how such a new challenge can be addressed by developing flow solvers running on high-end computing platforms, using thousands of computing cores. Parallel strategies used by modern flow solvers are discussed with particular emphases on mesh-partitioning, load balancing and communication. Two examples are used to illustrate these concepts: a multi-block structured code and an unstructured code. Parallel computing strategies used with both flow solvers are detailed and compared. This comparison indicates that mesh-partitioning and load balancing are more straightforward with unstructured grids than with multi-block structured meshes. However, the mesh-partitioning stage can be challenging for unstructured grids, mainly due to memory limitations of the newly developed massively parallel architectures. Finally, detailed investigations show that the impact of mesh-partitioning on the numerical CFD solutions, due to rounding errors and block splitting, may be of importance and should be accurately addressed before qualifying massively parallel CFD tools for a routine industrial use.

  12. Improving the Bandwidth Selection in Kernel Equating

    Science.gov (United States)

    Andersson, Björn; von Davier, Alina A.

    2014-01-01

    We investigate the current bandwidth selection methods in kernel equating and propose a method based on Silverman's rule of thumb for selecting the bandwidth parameters. In kernel equating, the bandwidth parameters have previously been obtained by minimizing a penalty function. This minimization process has been criticized by practitioners…

  13. Absorbed dose calibration factors for parallel-plate chambers in high energy photon beams

    International Nuclear Information System (INIS)

    McEwen, M.R.; Duane, S.; Thomas, R.A.S.

    2002-01-01

    An investigation was carried out into the performance of parallel-plate chambers in 60 Co and MV photon beams. The aim was to derive calibration factors, investigate chamber-to-chamber variability and provide much-needed information on the use of parallel-plate chambers in high-energy X-ray beams. A set of NE2561/NE2611 reference chambers, calibrated against the primary standard graphite calorimeter is used for the dissemination of absorbed dose to water. The parallel-plate chambers were calibrated by comparison with the NPL reference chambers in a water phantom. Two types of parallel-plate chamber were investigated - the NACP -02 and Roos and measurements were made at 60 C0 and 6 linac photon energies (6-19 MV). Calibration factors were derived together with polarity corrections. The standard uncertainty in the calibration of a chamber in terms of absorbed dose to water is estimated to be ±0.75%. The results of the polarity measurements were somewhat confusing. One would expect the correction to be small and previous measurements in electron beams have indicated that there is little variation between chambers of these types. However, some chambers gave unexpectedly large polarity corrections, up to 0.8%. By contrast the measured polarity correction for a NE2611 chamber was less than 0.13% at all energies. The reason for these large polarity corrections is not clear, but experimental error and linac variations have been ruled out. By combining the calibration data for the different chambers it was possible to obtain experimental k Q factors for the two chamber types. It would appear from the data that the variations between chambers of the same type are random and one can therefore define a generic curve for each chamber type. These are presented in Figure 1, together with equivalent data for two cylindrical chamber types - NE2561/NE2611 and NE2571. As can be seen, there is a clear difference between the curves for the cylindrical chambers and those for the

  14. Modeling of fatigue crack induced nonlinear ultrasonics using a highly parallelized explicit local interaction simulation approach

    Science.gov (United States)

    Shen, Yanfeng; Cesnik, Carlos E. S.

    2016-04-01

    This paper presents a parallelized modeling technique for the efficient simulation of nonlinear ultrasonics introduced by the wave interaction with fatigue cracks. The elastodynamic wave equations with contact effects are formulated using an explicit Local Interaction Simulation Approach (LISA). The LISA formulation is extended to capture the contact-impact phenomena during the wave damage interaction based on the penalty method. A Coulomb friction model is integrated into the computation procedure to capture the stick-slip contact shear motion. The LISA procedure is coded using the Compute Unified Device Architecture (CUDA), which enables the highly parallelized supercomputing on powerful graphic cards. Both the explicit contact formulation and the parallel feature facilitates LISA's superb computational efficiency over the conventional finite element method (FEM). The theoretical formulations based on the penalty method is introduced and a guideline for the proper choice of the contact stiffness is given. The convergence behavior of the solution under various contact stiffness values is examined. A numerical benchmark problem is used to investigate the new LISA formulation and results are compared with a conventional contact finite element solution. Various nonlinear ultrasonic phenomena are successfully captured using this contact LISA formulation, including the generation of nonlinear higher harmonic responses. Nonlinear mode conversion of guided waves at fatigue cracks is also studied.

  15. Progress on H5Part: A Portable High Performance Parallel Data Interface for Electromagnetics Simulations

    International Nuclear Information System (INIS)

    Adelmann, Andreas; Gsell, Achim; Oswald, Benedikt; Schietinger, Thomas; Bethel, Wes; Shalf, John; Siegerist, Cristina; Stockinger, Kurt

    2007-01-01

    Significant problems facing all experimental and computational sciences arise from growing data size and complexity. Common to all these problems is the need to perform efficient data I/O on diverse computer architectures. In our scientific application, the largest parallel particle simulations generate vast quantities of six-dimensional data. Such a simulation run produces data for an aggregate data size up to several TB per run. Motivated by the need to address data I/O and access challenges, we have implemented H5Part, an open source data I/O API that simplifies the use of the Hierarchical Data Format v5 library (HDF5). HDF5 is an industry standard for high performance, cross-platform data storage and retrieval that runs on all contemporary architectures from large parallel supercomputers to laptops. H5Part, which is oriented to the needs of the particle physics and cosmology communities, provides support for parallel storage and retrieval of particles, structured and in the future unstructured meshes. In this paper, we describe recent work focusing on I/O support for particles and structured meshes and provide data showing performance on modern supercomputer architectures like the IBM POWER 5

  16. A Highly Parallel and Scalable Motion Estimation Algorithm with GPU for HEVC

    Directory of Open Access Journals (Sweden)

    Yun-gang Xue

    2017-01-01

    Full Text Available We propose a highly parallel and scalable motion estimation algorithm, named multilevel resolution motion estimation (MLRME for short, by combining the advantages of local full search and downsampling. By subsampling a video frame, a large amount of computation is saved. While using the local full-search method, it can exploit massive parallelism and make full use of the powerful modern many-core accelerators, such as GPU and Intel Xeon Phi. We implanted the proposed MLRME into HM12.0, and the experimental results showed that the encoding quality of the MLRME method is close to that of the fast motion estimation in HEVC, which declines by less than 1.5%. We also implemented the MLRME with CUDA, which obtained 30–60x speed-up compared to the serial algorithm on single CPU. Specifically, the parallel implementation of MLRME on a GTX 460 GPU can meet the real-time coding requirement with about 25 fps for the 2560×1600 video format, while, for 832×480, the performance is more than 100 fps.

  17. Parallel optoelectronic trinary signed-digit division

    Science.gov (United States)

    Alam, Mohammad S.

    1999-03-01

    The trinary signed-digit (TSD) number system has been found to be very useful for parallel addition and subtraction of any arbitrary length operands in constant time. Using the TSD addition and multiplication modules as the basic building blocks, we develop an efficient algorithm for performing parallel TSD division in constant time. The proposed division technique uses one TSD subtraction and two TSD multiplication steps. An optoelectronic correlator based architecture is suggested for implementation of the proposed TSD division algorithm, which fully exploits the parallelism and high processing speed of optics. An efficient spatial encoding scheme is used to ensure better utilization of space bandwidth product of the spatial light modulators used in the optoelectronic implementation.

  18. Fluid/Structure Interaction Studies of Aircraft Using High Fidelity Equations on Parallel Computers

    Science.gov (United States)

    Guruswamy, Guru; VanDalsem, William (Technical Monitor)

    1994-01-01

    Abstract Aeroelasticity which involves strong coupling of fluids, structures and controls is an important element in designing an aircraft. Computational aeroelasticity using low fidelity methods such as the linear aerodynamic flow equations coupled with the modal structural equations are well advanced. Though these low fidelity approaches are computationally less intensive, they are not adequate for the analysis of modern aircraft such as High Speed Civil Transport (HSCT) and Advanced Subsonic Transport (AST) which can experience complex flow/structure interactions. HSCT can experience vortex induced aeroelastic oscillations whereas AST can experience transonic buffet associated structural oscillations. Both aircraft may experience a dip in the flutter speed at the transonic regime. For accurate aeroelastic computations at these complex fluid/structure interaction situations, high fidelity equations such as the Navier-Stokes for fluids and the finite-elements for structures are needed. Computations using these high fidelity equations require large computational resources both in memory and speed. Current conventional super computers have reached their limitations both in memory and speed. As a result, parallel computers have evolved to overcome the limitations of conventional computers. This paper will address the transition that is taking place in computational aeroelasticity from conventional computers to parallel computers. The paper will address special techniques needed to take advantage of the architecture of new parallel computers. Results will be illustrated from computations made on iPSC/860 and IBM SP2 computer by using ENSAERO code that directly couples the Euler/Navier-Stokes flow equations with high resolution finite-element structural equations.

  19. Drainage network extraction from a high-resolution DEM using parallel programming in the .NET Framework

    Science.gov (United States)

    Du, Chao; Ye, Aizhong; Gan, Yanjun; You, Jinjun; Duan, Qinyun; Ma, Feng; Hou, Jingwen

    2017-12-01

    High-resolution Digital Elevation Models (DEMs) can be used to extract high-accuracy prerequisite drainage networks. A higher resolution represents a larger number of grids. With an increase in the number of grids, the flow direction determination will require substantial computer resources and computing time. Parallel computing is a feasible method with which to resolve this problem. In this paper, we proposed a parallel programming method within the .NET Framework with a C# Compiler in a Windows environment. The basin is divided into sub-basins, and subsequently the different sub-basins operate on multiple threads concurrently to calculate flow directions. The method was applied to calculate the flow direction of the Yellow River basin from 3 arc-second resolution SRTM DEM. Drainage networks were extracted and compared with HydroSHEDS river network to assess their accuracy. The results demonstrate that this method can calculate the flow direction from high-resolution DEMs efficiently and extract high-precision continuous drainage networks.

  20. Development of high-resolution x-ray CT system using parallel beam geometry

    Energy Technology Data Exchange (ETDEWEB)

    Yoneyama, Akio, E-mail: akio.yoneyama.bu@hitachi.com; Baba, Rika [Central Research Laboratory, Hitachi Ltd., Hatoyama, Saitama (Japan); Hyodo, Kazuyuki [Institute of Materials Science, High Energy Accelerator Research Organization, Tsukuba, Ibaraki (Japan); Takeda, Tohoru [School of Allied Health Sciences, Kitasato University, Sagamihara, Kanagawa (Japan); Nakano, Haruhisa; Maki, Koutaro [Department of Orthodontics, School of Dentistry Showa University, Ota-ku, Tokyo (Japan); Sumitani, Kazushi; Hirai, Yasuharu [Kyushu Synchrotron Light Research Center, Tosu, Saga (Japan)

    2016-01-28

    For fine three-dimensional observations of large biomedical and organic material samples, we developed a high-resolution X-ray CT system. The system consists of a sample positioner, a 5-μm scintillator, microscopy lenses, and a water-cooled sCMOS detector. Parallel beam geometry was adopted to attain a field of view of a few mm square. A fine three-dimensional image of birch branch was obtained using a 9-keV X-ray at BL16XU of SPring-8 in Japan. The spatial resolution estimated from the line profile of a sectional image was about 3 μm.

  1. Investigation of density-wave oscillation in parallel boiling channels under high pressure

    International Nuclear Information System (INIS)

    Ming Xiao; Xuejun Chen; Mingyuan Zhang

    1992-01-01

    This paper presents experimental results on density-wave instability in parallel boiling channels. Experiments have been done in a high pressure steam-water loop. Different types of two-phase flow instabilities have been observed, including density-wave oscillation, pressure-drop type oscillation, thermal oscillation and secondary density-wave oscillation. The secondary density-wave oscillation appears at very low exit steam quality (less than 0.1) and at the positive portion of Δ P-G curves with both channels' flow rate oscillating in phase. Density-wave oscillation can appear at pressure up to 192 bar and disappear over 207 bar. (6 figures) (Author)

  2. Design of a highly parallel board-level-interconnection with 320 Gbps capacity

    Science.gov (United States)

    Lohmann, U.; Jahns, J.; Limmer, S.; Fey, D.; Bauer, H.

    2012-01-01

    A parallel board-level interconnection design is presented consisting of 32 channels, each operating at 10 Gbps. The hardware uses available optoelectronic components (VCSEL, TIA, pin-diodes) and a combination of planarintegrated free-space optics, fiber-bundles and available MEMS-components, like the DMD™ from Texas Instruments. As a specific feature, we present a new modular inter-board interconnect, realized by 3D fiber-matrix connectors. The performance of the interconnect is evaluated with regard to optical properties and power consumption. Finally, we discuss the application of the interconnect for strongly distributed system architectures, as, for example, in high performance embedded computing systems and data centers.

  3. A Novel Technique for Design of Ultra High Tunable Electrostatic Parallel Plate RF MEMS Variable Capacitor

    Science.gov (United States)

    Baghelani, Masoud; Ghavifekr, Habib Badri

    2017-12-01

    This paper introduces a novel method for designing of low actuation voltage, high tuning ratio electrostatic parallel plate RF MEMS variable capacitors. It is feasible to achieve ultra-high tuning ratios way beyond 1.5:1 barrier, imposed by pull-in effect, by the proposed method. The proposed method is based on spring strengthening of the structure just before the unstable region. Spring strengthening could be realized by embedding some dimples on the spring arms with the precise height. These dimples shorten the spring length when achieved to the substrate. By the proposed method, as high tuning ratios as 7.5:1 is attainable by only considering four dimple sets. The required actuation voltage for this high tuning ratio is 14.33 V which is simply achievable on-chip by charge pump circuits. Brownian noise effect is also discussed and mechanical natural frequency of the structure is calculated.

  4. High-speed parallel implementation of a modified PBR algorithm on DSP-based EH topology

    Science.gov (United States)

    Rajan, K.; Patnaik, L. M.; Ramakrishna, J.

    1997-08-01

    Algebraic Reconstruction Technique (ART) is an age-old method used for solving the problem of three-dimensional (3-D) reconstruction from projections in electron microscopy and radiology. In medical applications, direct 3-D reconstruction is at the forefront of investigation. The simultaneous iterative reconstruction technique (SIRT) is an ART-type algorithm with the potential of generating in a few iterations tomographic images of a quality comparable to that of convolution backprojection (CBP) methods. Pixel-based reconstruction (PBR) is similar to SIRT reconstruction, and it has been shown that PBR algorithms give better quality pictures compared to those produced by SIRT algorithms. In this work, we propose a few modifications to the PBR algorithms. The modified algorithms are shown to give better quality pictures compared to PBR algorithms. The PBR algorithm and the modified PBR algorithms are highly compute intensive, Not many attempts have been made to reconstruct objects in the true 3-D sense because of the high computational overhead. In this study, we have developed parallel two-dimensional (2-D) and 3-D reconstruction algorithms based on modified PBR. We attempt to solve the two problems encountered by the PBR and modified PBR algorithms, i.e., the long computational time and the large memory requirements, by parallelizing the algorithm on a multiprocessor system. We investigate the possible task and data partitioning schemes by exploiting the potential parallelism in the PBR algorithm subject to minimizing the memory requirement. We have implemented an extended hypercube (EH) architecture for the high-speed execution of the 3-D reconstruction algorithm using the commercially available fast floating point digital signal processor (DSP) chips as the processing elements (PEs) and dual-port random access memories (DPR) as channels between the PEs. We discuss and compare the performances of the PBR algorithm on an IBM 6000 RISC workstation, on a Silicon

  5. A Parallel Strategy for High-speed Interpolation of CNC Using Data Space Constraint Method

    Directory of Open Access Journals (Sweden)

    Shuan-qiang Yang

    2013-12-01

    Full Text Available A high-speed interpolation scheme using parallel computing is proposed in this paper. The interpolation method is divided into two tasks, namely, the rough task executing in PC and the fine task in the I/O card. During the interpolation procedure, the double buffers are constructed to exchange the interpolation data between the two tasks. Then, the data space constraint method is adapted to ensure the reliable and continuous data communication between the two buffers. Therefore, the proposed scheme can be realized in the common distribution of the operation systems without real-time performance. The high-speed and high-precision motion control can be achieved as well. Finally, an experiment is conducted on the self-developed CNC platform, the test results are shown to verify the proposed method.

  6. A 10-bit column-parallel cyclic ADC for high-speed CMOS image sensors

    International Nuclear Information System (INIS)

    Han Ye; Li Quanliang; Shi Cong; Wu Nanjian

    2013-01-01

    This paper presents a high-speed column-parallel cyclic analog-to-digital converter (ADC) for a CMOS image sensor. A correlated double sampling (CDS) circuit is integrated in the ADC, which avoids a stand-alone CDS circuit block. An offset cancellation technique is also introduced, which reduces the column fixed-pattern noise (FPN) effectively. One single channel ADC with an area less than 0.02 mm 2 was implemented in a 0.13 μm CMOS image sensor process. The resolution of the proposed ADC is 10-bit, and the conversion rate is 1.6 MS/s. The measured differential nonlinearity and integral nonlinearity are 0.89 LSB and 6.2 LSB together with CDS, respectively. The power consumption from 3.3 V supply is only 0.66 mW. An array of 48 10-bit column-parallel cyclic ADCs was integrated into an array of CMOS image sensor pixels. The measured results indicated that the ADC circuit is suitable for high-speed CMOS image sensors. (semiconductor integrated circuits)

  7. Encoding methods for B1+ mapping in parallel transmit systems at ultra high field

    Science.gov (United States)

    Tse, Desmond H. Y.; Poole, Michael S.; Magill, Arthur W.; Felder, Jörg; Brenner, Daniel; Jon Shah, N.

    2014-08-01

    Parallel radiofrequency (RF) transmission, either in the form of RF shimming or pulse design, has been proposed as a solution to the B1+ inhomogeneity problem in ultra high field magnetic resonance imaging. As a prerequisite, accurate B1+ maps from each of the available transmit channels are required. In this work, four different encoding methods for B1+ mapping, namely 1-channel-on, all-channels-on-except-1, all-channels-on-1-inverted and Fourier phase encoding, were evaluated using dual refocusing acquisition mode (DREAM) at 9.4 T. Fourier phase encoding was demonstrated in both phantom and in vivo to be the least susceptible to artefacts caused by destructive RF interference at 9.4 T. Unlike the other two interferometric encoding schemes, Fourier phase encoding showed negligible dependency on the initial RF phase setting and therefore no prior B1+ knowledge is required. Fourier phase encoding also provides a flexible way to increase the number of measurements to increase SNR, and to allow further reduction of artefacts by weighted decoding. These advantages of Fourier phase encoding suggest that it is a good choice for B1+ mapping in parallel transmit systems at ultra high field.

  8. High-Resolution Electronics: Spontaneous Patterning of High-Resolution Electronics via Parallel Vacuum Ultraviolet (Adv. Mater. 31/2016).

    Science.gov (United States)

    Liu, Xuying; Kanehara, Masayuki; Liu, Chuan; Sakamoto, Kenji; Yasuda, Takeshi; Takeya, Jun; Minari, Takeo

    2016-08-01

    On page 6568, T. Minari and co-workers describe spontaneous patterning based on the parallel vacuum ultraviolet (PVUV) technique, enabling the homogeneous integration of complex, high-resolution electronic circuits, even on large-scale, flexible, transparent substrates. Irradiation of PVUV to the hydrophobic polymer surface precisely renders the selected surface into highly wettable regions with sharply defined boundaries, which spontaneously guides a metal nanoparticle ink into a series of circuit lines and gaps with the widths down to a resolution of 1 μm. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. MulticoreBSP for C : A high-performance library for shared-memory parallel programming

    NARCIS (Netherlands)

    Yzelman, A. N.; Bisseling, R. H.; Roose, D.; Meerbergen, K.

    2014-01-01

    The bulk synchronous parallel (BSP) model, as well as parallel programming interfaces based on BSP, classically target distributed-memory parallel architectures. In earlier work, Yzelman and Bisseling designed a MulticoreBSP for Java library specifically for shared-memory architectures. In the

  10. Transparent Nanopore Cavity Arrays Enable Highly Parallelized Optical Studies of Single Membrane Proteins on Chip.

    Science.gov (United States)

    Diederichs, Tim; Nguyen, Quoc Hung; Urban, Michael; Tampé, Robert; Tornow, Marc

    2018-06-13

    Membrane proteins involved in transport processes are key targets for pharmaceutical research and industry. Despite continuous improvements and new developments in the field of electrical readouts for the analysis of transport kinetics, a well-suited methodology for high-throughput characterization of single transporters with nonionic substrates and slow turnover rates is still lacking. Here, we report on a novel architecture of silicon chips with embedded nanopore microcavities, based on a silicon-on-insulator technology for high-throughput optical readouts. Arrays containing more than 14 000 inverted-pyramidal cavities of 50 femtoliter volumes and 80 nm circular pore openings were constructed via high-resolution electron-beam lithography in combination with reactive ion etching and anisotropic wet etching. These cavities feature both, an optically transparent bottom and top cap. Atomic force microscopy analysis reveals an overall extremely smooth chip surface, particularly in the vicinity of the nanopores, which exhibits well-defined edges. Our unprecedented transparent chip design provides parallel and independent fluorescent readout of both cavities and buffer reservoir for unbiased single-transporter recordings. Spreading of large unilamellar vesicles with efficiencies up to 96% created nanopore-supported lipid bilayers, which are stable for more than 1 day. A high lipid mobility in the supported membrane was determined by fluorescent recovery after photobleaching. Flux kinetics of α-hemolysin were characterized at single-pore resolution with a rate constant of 0.96 ± 0.06 × 10 -3 s -1 . Here, we deliver an ideal chip platform for pharmaceutical research, which features high parallelism and throughput, synergistically combined with single-transporter resolution.

  11. Evaluation of DEC`s GIGAswitch for distributed parallel computing

    Energy Technology Data Exchange (ETDEWEB)

    Chen, H.; Hutchins, J.; Brandt, J.

    1993-10-01

    One of Sandia`s research efforts is to reduce the end-to-end communication delay in a parallel-distributed computing environment. GIGAswitch is DEC`s implementation of a gigabit local area network based on switched FDDI technology. Using the GIGAswitch, the authors intend to minimize the medium access latency suffered by shared-medium FDDI technology. Experimental results show that the GIGAswitch adds 16.5 microseconds of switching and bridging delay to an end-to-end communication. Although the added latency causes a 1.8% throughput degradation and a 5% line efficiency degradation, the availability of dedicated bandwidth is much more than what is available to a workstation on a shared medium. For example, ten directly connected workstations each would have a dedicated bandwidth of 95 Mbps, but if they were sharing the FDDI bandwidth, each would have 10% of the total bandwidth, i.e., less than 10 Mbps. In addition, they have found that when there is no output port contention, the switch`s aggregate bandwidth will scale up to multiples of its port bandwidth. However, with output port contention, the throughput and latency performance suffered significantly. Their mathematical and simulation models indicate that the GIGAswitch line efficiency could be as low as 63% when there are nine input ports contending for the same output port. The data indicate that the delay introduced by contention at the server workstation is 50 times that introduced by the GIGAswitch. The authors conclude that the GIGAswitch meets the performance requirements of today`s high-end workstations and that the switched FDDI technology provides an alternative that utilizes existing workstation interfaces while increasing the aggregate bandwidth. However, because the speed of workstations is increasing by a factor of 2 every 1.5 years, the switched FDDI technology is only good as an interim solution.

  12. High-Performance Parallel and Stream Processing of X-ray Microdiffraction Data on Multicores

    International Nuclear Information System (INIS)

    Bauer, Michael A; McIntyre, Stewart; Xie Yuzhen; Biem, Alain; Tamura, Nobumichi

    2012-01-01

    We present the design and implementation of a high-performance system for processing synchrotron X-ray microdiffraction (XRD) data in IBM InfoSphere Streams on multicore processors. We report on the parallel and stream processing techniques that we use to harvest the power of clusters of multicores to analyze hundreds of gigabytes of synchrotron XRD data in order to reveal the microtexture of polycrystalline materials. The timing to process one XRD image using one pipeline is about ten times faster than the best C program at present. With the support of InfoSphere Streams platform, our software is able to be scaled up to operate on clusters of multi-cores for processing multiple images concurrently. This system provides a high-performance processing kernel to achieve near real-time data analysis of image data from synchrotron experiments.

  13. Parallel Backprojection: A Case Study in High-Performance Reconfigurable Computing

    Directory of Open Access Journals (Sweden)

    Cordes Ben

    2009-01-01

    Full Text Available High-performance reconfigurable computing (HPRC is a novel approach to provide large-scale computing power to modern scientific applications. Using both general-purpose processors and FPGAs allows application designers to exploit fine-grained and coarse-grained parallelism, achieving high degrees of speedup. One scientific application that benefits from this technique is backprojection, an image formation algorithm that can be used as part of a synthetic aperture radar (SAR processing system. We present an implementation of backprojection for SAR on an HPRC system. Using simulated data taken at a variety of ranges, our implementation runs over 200 times faster than a similar software program, with an overall application speedup better than 50x. The backprojection application is easily parallelizable, achieving near-linear speedup when run on multiple nodes of a clustered HPRC system. The results presented can be applied to other systems and other algorithms with similar characteristics.

  14. Parallel Backprojection: A Case Study in High-Performance Reconfigurable Computing

    Directory of Open Access Journals (Sweden)

    2009-03-01

    Full Text Available High-performance reconfigurable computing (HPRC is a novel approach to provide large-scale computing power to modern scientific applications. Using both general-purpose processors and FPGAs allows application designers to exploit fine-grained and coarse-grained parallelism, achieving high degrees of speedup. One scientific application that benefits from this technique is backprojection, an image formation algorithm that can be used as part of a synthetic aperture radar (SAR processing system. We present an implementation of backprojection for SAR on an HPRC system. Using simulated data taken at a variety of ranges, our implementation runs over 200 times faster than a similar software program, with an overall application speedup better than 50x. The backprojection application is easily parallelizable, achieving near-linear speedup when run on multiple nodes of a clustered HPRC system. The results presented can be applied to other systems and other algorithms with similar characteristics.

  15. Homemade Buckeye-Pi: A Learning Many-Node Platform for High-Performance Parallel Computing

    Science.gov (United States)

    Amooie, M. A.; Moortgat, J.

    2017-12-01

    We report on the "Buckeye-Pi" cluster, the supercomputer developed in The Ohio State University School of Earth Sciences from 128 inexpensive Raspberry Pi (RPi) 3 Model B single-board computers. Each RPi is equipped with fast Quad Core 1.2GHz ARMv8 64bit processor, 1GB of RAM, and 32GB microSD card for local storage. Therefore, the cluster has a total RAM of 128GB that is distributed on the individual nodes and a flash capacity of 4TB with 512 processors, while it benefits from low power consumption, easy portability, and low total cost. The cluster uses the Message Passing Interface protocol to manage the communications between each node. These features render our platform the most powerful RPi supercomputer to date and suitable for educational applications in high-performance-computing (HPC) and handling of large datasets. In particular, we use the Buckeye-Pi to implement optimized parallel codes in our in-house simulator for subsurface media flows with the goal of achieving a massively-parallelized scalable code. We present benchmarking results for the computational performance across various number of RPi nodes. We believe our project could inspire scientists and students to consider the proposed unconventional cluster architecture as a mainstream and a feasible learning platform for challenging engineering and scientific problems.

  16. High Performance Computation of a Jet in Crossflow by Lattice Boltzmann Based Parallel Direct Numerical Simulation

    Directory of Open Access Journals (Sweden)

    Jiang Lei

    2015-01-01

    Full Text Available Direct numerical simulation (DNS of a round jet in crossflow based on lattice Boltzmann method (LBM is carried out on multi-GPU cluster. Data parallel SIMT (single instruction multiple thread characteristic of GPU matches the parallelism of LBM well, which leads to the high efficiency of GPU on the LBM solver. With present GPU settings (6 Nvidia Tesla K20M, the present DNS simulation can be completed in several hours. A grid system of 1.5 × 108 is adopted and largest jet Reynolds number reaches 3000. The jet-to-free-stream velocity ratio is set as 3.3. The jet is orthogonal to the mainstream flow direction. The validated code shows good agreement with experiments. Vortical structures of CRVP, shear-layer vortices and horseshoe vortices, are presented and analyzed based on velocity fields and vorticity distributions. Turbulent statistical quantities of Reynolds stress are also displayed. Coherent structures are revealed in a very fine resolution based on the second invariant of the velocity gradients.

  17. α spectrometer of parallel plate grid ionization chamber of high energy resolution

    International Nuclear Information System (INIS)

    Tong Boting; Wang Jianqing; Dong Mingli; Tang Peijia; Wang Xiaorong; Lin Cansheng

    2000-01-01

    Parallel plate grid ionization chamber with cathode area of 300 cm 2 was developed and applied to detect minimum α-emitters. It consist of a vacuum system, a gas cycle system of the parallel plate grid ionization chamber, electronics (a high voltage supply, a pre-amplifier and a main amplifier) and a computer-multichannel analyzer. The energy resolution is 23 keV FWHM for the 244 Cm electrostatic precipitated source. The integral background is typically 10 counts/h between 4 and 6 MeV. The detector efficiency is 50%. The minimum detecting activity is 3 x 10 -4 Bq (3σ, 30 hours). This spectrometer is suitable for detecting various samples, such as samples of the soil, water, air, bion, food, structural material, geology, archaeology, α-emitters of after processing and measuring α activity of accounting for and control of nuclear material and monitoring the artificial radioactivity nuclides of environment samples around nuclear facilities. The spectrometer is equipped with apparatus for preparing large area α source by using vacuum deposition or ultrasonic pulverization. The operating program of preparing source is simple. The source thickness can be kept in 40-60 μm/cm 2

  18. Parallel and series FED microstrip array with high efficiency and low cross polarization

    Science.gov (United States)

    Huang, John (Inventor)

    1995-01-01

    A microstrip array antenna for vertically polarized fan beam (approximately 2 deg x 50 deg) for C-band SAR applications with a physical area of 1.7 m by 0.17 m comprises two rows of patch elements and employs a parallel feed to left- and right-half sections of the rows. Each section is divided into two segments that are fed in parallel with the elements in each segment fed in series through matched transmission lines for high efficiency. The inboard section has half the number of patch elements of the outboard section, and the outboard sections, which have tapered distribution with identical transmission line sections, terminated with half wavelength long open-circuit stubs so that the remaining energy is reflected and radiated in phase. The elements of the two inboard segments of the two left- and right-half sections are provided with tapered transmission lines from element to element for uniform power distribution over the central third of the entire array antenna. The two rows of array elements are excited at opposite patch feed locations with opposite (180 deg difference) phases for reduced cross-polarization.

  19. A Novel High Bandwidth Current Control Strategy for SiC mosfet Based Active Front-End Rectifiers Under Unbalanced Input Voltage Conditions

    DEFF Research Database (Denmark)

    Maheshwari, Ramkrishan; Trintis, Ionut; Török, Lajos

    2017-01-01

    SiC mosfet based converters are capable of high switching frequency operation. In this paper, the converter is operated with 50-kHz switching frequency for an active front-end rectifier application. Due to high switching frequency, the grid-side filter size is reduced, and the possibility of a high...

  20. Controlling Laser Plasma Instabilities Using Temporal Bandwidth

    Science.gov (United States)

    Tsung, Frank; Weaver, J.; Lehmberg, R.

    2016-10-01

    We are performing particle-in-cell simulations using the code OSIRIS to study the effects of laser plasma interactions in the presence of temporal bandwidth under conditions relevant to current and future experiments on the NIKE laser. Our simulations show that, for sufficiently large bandwidth (where the inverse bandwidth is comparable with the linear growth time), the saturation level, and the distribution of hot electrons, can be effected by the addition of temporal bandwidths (which can be accomplished in experiments using beam smoothing techniques such as ISI). We will quantify these effects and investigate higher dimensional effects such as laser speckles. This work is supported by DOE and NRL.

  1. Parallel computation of fluid-structural interactions using high resolution upwind schemes

    Science.gov (United States)

    Hu, Zongjun

    An efficient and accurate solver is developed to simulate the non-linear fluid-structural interactions in turbomachinery flutter flows. A new low diffusion E-CUSP scheme, Zha CUSP scheme, is developed to improve the efficiency and accuracy of the inviscid flux computation. The 3D unsteady Navier-Stokes equations with the Baldwin-Lomax turbulence model are solved using the finite volume method with the dual-time stepping scheme. The linearized equations are solved with Gauss-Seidel line iterations. The parallel computation is implemented using MPI protocol. The solver is validated with 2D cases for its turbulence modeling, parallel computation and unsteady calculation. The Zha CUSP scheme is validated with 2D cases, including a supersonic flat plate boundary layer, a transonic converging-diverging nozzle and a transonic inlet diffuser. The Zha CUSP2 scheme is tested with 3D cases, including a circular-to-rectangular nozzle, a subsonic compressor cascade and a transonic channel. The Zha CUSP schemes are proved to be accurate, robust and efficient in these tests. The steady and unsteady separation flows in a 3D stationary cascade under high incidence and three inlet Mach numbers are calculated to study the steady state separation flow patterns and their unsteady oscillation characteristics. The leading edge vortex shedding is the mechanism behind the unsteady characteristics of the high incidence separated flows. The separation flow characteristics is affected by the inlet Mach number. The blade aeroelasticity of a linear cascade with forced oscillating blades is studied using parallel computation. A simplified two-passage cascade with periodic boundary condition is first calculated under a medium frequency and a low incidence. The full scale cascade with 9 blades and two end walls is then studied more extensively under three oscillation frequencies and two incidence angles. The end wall influence and the blade stability are studied and compared under different

  2. FOCEX: A fiber-optic extender for a high speed parallel RS485 data cable

    International Nuclear Information System (INIS)

    Meadows, J.T.; Anderson, J.T.; Cooper, P.S.; Engelfried, J.; Franzen, J.W.; Forster, B.G.; Levinson, F.; Rawls, J.; Haber, S.

    1995-05-01

    For longer-distant, high speed data links, optical fibre becomes most cost-effective than copper or other hard wire cable systems. Fermilab supplied to Finisar Corp. of Menlo Park, CA., a set of specifications for card functions, sizes and interconnector pin assignments. Finisar designed and assembled a set of fiber optical P.C. cards using 100 megabyte/sec commercial optoelectronics and a serialization and deserialization HOT-ROD chipset designed by GAZELLE Microcircuits, Inc. (A Tri Quint Semiconductors company). The cooperative effort between Fermilab and Finisar has allowed Fermilab to created a reliable 50 Megabytes/sec (40 bit parallel RS485 DART data bus) cable to cable extender using a virtually invisible Fiber Channel point-to-point(FC-0) fiber optical single-simplex system. The system is easily capable of sustaining a 50 megabytes/sec of data, control and status line throughput at distances of 1625 feet (500 meters) using standard multi-mode fiber

  3. Nonlinear Elastodynamic Behaviour Analysis of High-Speed Spatial Parallel Coordinate Measuring Machines

    Directory of Open Access Journals (Sweden)

    Xiulong Chen

    2012-10-01

    Full Text Available In order to study the elastodynamic behaviour of 4- universal joints- prismatic pairs- spherical joints / universal joints- prismatic pairs- universal joints 4-UPS-UPU high-speed spatial PCMMs(parallel coordinate measuring machines, the nonlinear time-varying dynamics model, which comprehensively considers geometric nonlinearity and the rigid-flexible coupling effect, is derived by using Lagrange equations and finite element methods. Based on the Newmark method, the kinematics output response of 4-UPS-UPU PCMMs is illustrated through numerical simulation. The results of the simulation show that the flexibility of the links is demonstrated to have a significant impact on the system dynamics response. This research can provide the important theoretical base of the optimization design and vibration control for 4-UPS-UPU PCMMs.

  4. Evaluation of emerging parallel optical link technology for high energy physics

    International Nuclear Information System (INIS)

    Chramowicz, J; Kwan, S; Prosser, A; Winchell, M

    2012-01-01

    Modern particle detectors utilize optical fiber links to deliver event data to upstream trigger and data processing systems. Future detector systems can benefit from the development of dense arrangements of high speed optical links emerging from industry advancements in transceiver technology. Supporting data transfers of up to 120 Gbps in each direction, optical engines permit assembly of the optical transceivers in close proximity to ASICs and FPGAs. Test results of some of these parallel components will be presented including the development of pluggable FPGA Mezzanine Cards equipped with optical engines to provide to collaborators on the Versatile Link Common Project for the HI-LHC at CERN. This work was supported by the U.S. Department of Energy, operated by Fermi Research Alliance, LLC under contract No. DE-AC02-07CH11359 with the United States Department of Energy.

  5. HPC-NMF: A High-Performance Parallel Algorithm for Nonnegative Matrix Factorization

    Energy Technology Data Exchange (ETDEWEB)

    2016-08-22

    NMF is a useful tool for many applications in different domains such as topic modeling in text mining, background separation in video analysis, and community detection in social networks. Despite its popularity in the data mining community, there is a lack of efficient distributed algorithms to solve the problem for big data sets. We propose a high-performance distributed-memory parallel algorithm that computes the factorization by iteratively solving alternating non-negative least squares (NLS) subproblems for $\\WW$ and $\\HH$. It maintains the data and factor matrices in memory (distributed across processors), uses MPI for interprocessor communication, and, in the dense case, provably minimizes communication costs (under mild assumptions). As opposed to previous implementation, our algorithm is also flexible: It performs well for both dense and sparse matrices, and allows the user to choose any one of the multiple algorithms for solving the updates to low rank factors $\\WW$ and $\\HH$ within the alternating iterations.

  6. High performance parallel computing of flows in complex geometries: II. Applications

    International Nuclear Information System (INIS)

    Gourdain, N; Gicquel, L; Staffelbach, G; Vermorel, O; Duchaine, F; Boussuge, J-F; Poinsot, T

    2009-01-01

    Present regulations in terms of pollutant emissions, noise and economical constraints, require new approaches and designs in the fields of energy supply and transportation. It is now well established that the next breakthrough will come from a better understanding of unsteady flow effects and by considering the entire system and not only isolated components. However, these aspects are still not well taken into account by the numerical approaches or understood whatever the design stage considered. The main challenge is essentially due to the computational requirements inferred by such complex systems if it is to be simulated by use of supercomputers. This paper shows how new challenges can be addressed by using parallel computing platforms for distinct elements of a more complex systems as encountered in aeronautical applications. Based on numerical simulations performed with modern aerodynamic and reactive flow solvers, this work underlines the interest of high-performance computing for solving flow in complex industrial configurations such as aircrafts, combustion chambers and turbomachines. Performance indicators related to parallel computing efficiency are presented, showing that establishing fair criterions is a difficult task for complex industrial applications. Examples of numerical simulations performed in industrial systems are also described with a particular interest for the computational time and the potential design improvements obtained with high-fidelity and multi-physics computing methods. These simulations use either unsteady Reynolds-averaged Navier-Stokes methods or large eddy simulation and deal with turbulent unsteady flows, such as coupled flow phenomena (thermo-acoustic instabilities, buffet, etc). Some examples of the difficulties with grid generation and data analysis are also presented when dealing with these complex industrial applications.

  7. High-speed technique based on a parallel projection correlation procedure for digital image correlation

    Science.gov (United States)

    Zaripov, D. I.; Renfu, Li

    2018-05-01

    The implementation of high-efficiency digital image correlation methods based on a zero-normalized cross-correlation (ZNCC) procedure for high-speed, time-resolved measurements using a high-resolution digital camera is associated with big data processing and is often time consuming. In order to speed-up ZNCC computation, a high-speed technique based on a parallel projection correlation procedure is proposed. The proposed technique involves the use of interrogation window projections instead of its two-dimensional field of luminous intensity. This simplification allows acceleration of ZNCC computation up to 28.8 times compared to ZNCC calculated directly, depending on the size of interrogation window and region of interest. The results of three synthetic test cases, such as a one-dimensional uniform flow, a linear shear flow and a turbulent boundary-layer flow, are discussed in terms of accuracy. In the latter case, the proposed technique is implemented together with an iterative window-deformation technique. On the basis of the results of the present work, the proposed technique is recommended to be used for initial velocity field calculation, with further correction using more accurate techniques.

  8. Electrothermal impedance spectroscopy measurement on high power LiMO2/Li4Ti5O12 battery cell with low bandwidth test setup

    DEFF Research Database (Denmark)

    Swierczynski, Maciej Jozef; Stroe, Daniel Loan; Stanciu, Tiberiu

    2015-01-01

    be executed on-line (e.g. in the electric vehicle Battery Management System). The Electrothermal Impedance Spectroscopy (ETIS) can be used as a relatively simple and fast method for non-destructive parametrization of the battery thermal models. However, the ETIS requires expensive galvanostat with high...

  9. Development of a parallel zoomed EVI sequence for high temporal resolution analysis of the BOLD response

    International Nuclear Information System (INIS)

    Rabrait, C.

    2006-01-01

    acquisition of one line out of two and one plane out new acquisition method was experimented with success both with block-designed and event related visual paradigms. An 80 x 80 x 120 mm 3 volume, containing the visual cortex, was acquired with a repetition time of 200 ms. In both cases, a robust activation was detected in the primary visual cortex, with a high statistical significance threshold (7). Actually, high scanning rates mostly benefit for hemodynamic response estimation. To estimate hemodynamic response functions from our event-related data, a non parametric unsupervised method (8) is applied to the activated clusters selected using the SPM2 software. In every tested clusters, the estimated response functions are close to the usually assumed shape, although no prior assumption about the shape of the response is made. Furthermore, a significant early negative response is sometimes seen, which i s generally difficult to observe at 1.5 T. Current studies now aim at obtaining good quality single-voxel hemodynamic response functions, in order to map the spatio-temporal features of the BOLD response. Activation maps based on the early negative response could also be a valuable application of our method, since this response is thought to be more co-localized with the true activated areas than the delayed positive response (9). Another goal of our future work is the optimization of new paradigms to better exploit zoomed parallel Echo Volumar Imaging properties. (author)

  10. Operational mesoscale atmospheric dispersion prediction using high performance parallel computing cluster for emergency response

    International Nuclear Information System (INIS)

    Srinivas, C.V.; Venkatesan, R.; Muralidharan, N.V.; Das, Someshwar; Dass, Hari; Eswara Kumar, P.

    2005-08-01

    An operational atmospheric dispersion prediction system is implemented on a cluster super computer for 'Online Emergency Response' for Kalpakkam nuclear site. The numerical system constitutes a parallel version of a nested grid meso-scale meteorological model MM5 coupled to a random walk particle dispersion model FLEXPART. The system provides 48 hour forecast of the local weather and radioactive plume dispersion due to hypothetical air borne releases in a range of 100 km around the site. The parallel code was implemented on different cluster configurations like distributed and shared memory systems. Results of MM5 run time performance for 1-day prediction are reported on all the machines available for testing. A reduction of 5 times in runtime is achieved using 9 dual Xeon nodes (18 physical/36 logical processors) compared to a single node sequential run. Based on the above run time results a cluster computer facility with 9-node Dual Xeon is commissioned at IGCAR for model operation. The run time of a triple nested domain MM5 is about 4 h for 24 h forecast. The system has been operated continuously for a few months and results were ported on the IMSc home page. Initial and periodic boundary condition data for MM5 are provided by NCMRWF, New Delhi. An alternative source is found to be NCEP, USA. These two sources provide the input data to the operational models at different spatial and temporal resolutions and using different assimilation methods. A comparative study on the results of forecast is presented using these two data sources for present operational use. Slight improvement is noticed in rainfall, winds, geopotential heights and the vertical atmospheric structure while using NCEP data probably because of its high spatial and temporal resolution. (author)

  11. On semidefinite programming bounds for graph bandwidth

    NARCIS (Netherlands)

    de Klerk, E.; Nagy, M.; Sotirov, R.

    2013-01-01

    In this paper, we propose two new lower bounds on graph bandwidth and cyclic bandwidth based on semidefinite programming (SDP) relaxations of the quadratic assignment problem. We compare the new bounds with two other SDP bounds reported in [A. Blum, G. Konjevod, R. Ravi, and S. Vempala,

  12. Directing Traffic: Managing Internet Bandwidth Fairly

    Science.gov (United States)

    Paine, Thomas A.; Griggs, Tyler J.

    2008-01-01

    Educational institutions today face budgetary restraints and scarce resources, complicating the decision of how to allot bandwidth for campus network users. Additionally, campus concerns over peer-to-peer networking (specifically outbound Internet traffic) have increased because of bandwidth and copyright issues. In this article, the authors…

  13. 47 CFR 2.202 - Bandwidths.

    Science.gov (United States)

    2010-10-01

    ... three numerals and one letter. The letter occupies the position of the decimal point and represents the... quality desired Speech and music, M=4000, Bandwidth: 8000 Hz= 8 kHz 8K00A3E Sound broadcasting, single... desired Speech and music, M=4000, Bandwidth: 4000 Hz= 4 kHz 4K00R3E Sound broadcasting, single-sideband...

  14. Bandwidth-on-demand motion control

    NARCIS (Netherlands)

    Van Loon, S.J.L.M.; Hunnekens, B.G.B.; Simon, A.S.; van de Wouw, N.; Heemels, W.P.M.H.

    2018-01-01

    In this brief, we introduce a 'bandwidth-on-demand' variable-gain control (VGC) strategy that allows for a varying bandwidth of the feedback controller. The proposed VGC can achieve improved performance given time-varying, reference-dependent performance requirements compared with linear

  15. Feasibility studies for a high energy physics MC program on massive parallel platforms

    International Nuclear Information System (INIS)

    Bertolotto, L.M.; Peach, K.J.; Apostolakis, J.; Bruschini, C.E.; Calafiura, P.; Gagliardi, F.; Metcalf, M.; Norton, A.; Panzer-Steindel, B.

    1994-01-01

    The parallelization of a Monte Carlo program for the NA48 experiment is presented. As a first step, a task farming structure was realized. Based on this, a further step, making use of a distributed database for showers in the electro-magnetic calorimeter, was implemented. Further possibilities for using parallel processing for a quasi-real time calibration of the calorimeter are described

  16. Modulator reliability and bandwidth improvement: replacing tetrodes with MOSFETs

    International Nuclear Information System (INIS)

    Donaldson, A.R.

    1982-01-01

    Three types of power MOS field effect transistors were studied with the intent of replacing a parallel pair of vacuum tube tetrodes in a linear modulator. The tetrodes have the shortest lifetimes of any other tubes in the system. The FETs offer definite performance advantages when compared to bipolar transistors and definite cost advantages when compared to vacuum tubes. Replacement of the tetrodes does however require careful consideration of voltage, current and to a lesser extent bandwidth capability in order to enhance overall modulator reliability without compromising present performance

  17. Highly sensitive wide bandwidth photodetector based on internal photoemission in CVD grown p-type MoS2/graphene Schottky junction.

    Science.gov (United States)

    Vabbina, PhaniKiran; Choudhary, Nitin; Chowdhury, Al-Amin; Sinha, Raju; Karabiyik, Mustafa; Das, Santanu; Choi, Wonbong; Pala, Nezih

    2015-07-22

    Two dimensional (2D) Molybdenum disulfide (MoS2) has evolved as a promising material for next generation optoelectronic devices owing to its unique electrical and optical properties, such as band gap modulation, high optical absorption, and increased luminescence quantum yield. The 2D MoS2 photodetectors reported in the literature have presented low responsivity compared to silicon based photodetectors. In this study, we assembled atomically thin p-type MoS2 with graphene to form a MoS2/graphene Schottky photodetector where photo generated holes travel from graphene to MoS2 over the Schottky barrier under illumination. We found that the p-type MoS2 forms a Schottky junction with graphene with a barrier height of 139 meV, which results in high photocurrent and wide spectral range of detection with wavelength selectivity. The fabricated photodetector showed excellent photosensitivity with a maximum photo responsivity of 1.26 AW(-1) and a noise equivalent power of 7.8 × 10(-12) W/√Hz at 1440 nm.

  18. Performance of the Low-Jitter High-Gain/Bandwidth Front-End Electronics of the HADES tRPC Wall

    Science.gov (United States)

    Belver, Daniel; Cabanelas, P.; Castro, E.; Garzon, J. A.; Gil, A.; Gonzalez-Diaz, D.; Koenig, W.; Traxler, M.

    2010-10-01

    A front-end electronics (FEE) chain for accurate time measurements has been developed for the new Resistive Plate Chamber (RPC)-based Time-of-Flight (TOF) wall of the High Acceptance Di-Electron Spectrometer (HADES). The wall covers an area of around 8 m2, divided in 6 sectors. In total, 1122 4-gap timing RPC cells are read-out by 2244 time and charge sensitive channels. The FEE chain consists of 2 custom-made boards: a 4-channel DaughterBOard (DBO) and a 32-channel MotherBOard (MBO). The DBO uses a fast 2 GHz amplifier feeding a dual high-speed discriminator. The time and charge information are encoded, respectively, in the leading edge and the width of an LVDS signal. Each MBO houses up to 8 DBOs providing them regulated voltage supply, threshold values via DACs, test signals and, additionally, routing out a signal proportional to the channel multiplicity needed for a 1st level trigger decision. The MBO delivers LVDS signals to a multi-purpose Trigger Readout Board (TRB) for data acquisition. The FEE allows achieving a system resolution around 75 ps fulfilling comfortably the requirements of the HADES upgrade .

  19. Integration experiences and performance studies of A COTS parallel archive systems

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Hsing-bung [Los Alamos National Laboratory; Scott, Cody [Los Alamos National Laboratory; Grider, Bary [Los Alamos National Laboratory; Torres, Aaron [Los Alamos National Laboratory; Turley, Milton [Los Alamos National Laboratory; Sanchez, Kathy [Los Alamos National Laboratory; Bremer, John [Los Alamos National Laboratory

    2010-01-01

    Current and future Archive Storage Systems have been asked to (a) scale to very high bandwidths, (b) scale in metadata performance, (c) support policy-based hierarchical storage management capability, (d) scale in supporting changing needs of very large data sets, (e) support standard interface, and (f) utilize commercial-off-the-shelf(COTS) hardware. Parallel file systems have been asked to do the same thing but at one or more orders of magnitude faster in performance. Archive systems continue to move closer to file systems in their design due to the need for speed and bandwidth, especially metadata searching speeds such as more caching and less robust semantics. Currently the number of extreme highly scalable parallel archive solutions is very small especially those that will move a single large striped parallel disk file onto many tapes in parallel. We believe that a hybrid storage approach of using COTS components and innovative software technology can bring new capabilities into a production environment for the HPC community much faster than the approach of creating and maintaining a complete end-to-end unique parallel archive software solution. In this paper, we relay our experience of integrating a global parallel file system and a standard backup/archive product with a very small amount of additional code to provide a scalable, parallel archive. Our solution has a high degree of overlap with current parallel archive products including (a) doing parallel movement to/from tape for a single large parallel file, (b) hierarchical storage management, (c) ILM features, (d) high volume (non-single parallel file) archives for backup/archive/content management, and (e) leveraging all free file movement tools in Linux such as copy, move, ls, tar, etc. We have successfully applied our working COTS Parallel Archive System to the current world's first petaflop/s computing system, LANL's Roadrunner, and demonstrated its capability to address requirements of

  20. Integration experiments and performance studies of a COTS parallel archive system

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Hsing-bung [Los Alamos National Laboratory; Scott, Cody [Los Alamos National Laboratory; Grider, Gary [Los Alamos National Laboratory; Torres, Aaron [Los Alamos National Laboratory; Turley, Milton [Los Alamos National Laboratory; Sanchez, Kathy [Los Alamos National Laboratory; Bremer, John [Los Alamos National Laboratory

    2010-06-16

    Current and future Archive Storage Systems have been asked to (a) scale to very high bandwidths, (b) scale in metadata performance, (c) support policy-based hierarchical storage management capability, (d) scale in supporting changing needs of very large data sets, (e) support standard interface, and (f) utilize commercial-off-the-shelf (COTS) hardware. Parallel file systems have been asked to do the same thing but at one or more orders of magnitude faster in performance. Archive systems continue to move closer to file systems in their design due to the need for speed and bandwidth, especially metadata searching speeds such as more caching and less robust semantics. Currently the number of extreme highly scalable parallel archive solutions is very small especially those that will move a single large striped parallel disk file onto many tapes in parallel. We believe that a hybrid storage approach of using COTS components and innovative software technology can bring new capabilities into a production environment for the HPC community much faster than the approach of creating and maintaining a complete end-to-end unique parallel archive software solution. In this paper, we relay our experience of integrating a global parallel file system and a standard backup/archive product with a very small amount of additional code to provide a scalable, parallel archive. Our solution has a high degree of overlap with current parallel archive products including (a) doing parallel movement to/from tape for a single large parallel file, (b) hierarchical storage management, (c) ILM features, (d) high volume (non-single parallel file) archives for backup/archive/content management, and (e) leveraging all free file movement tools in Linux such as copy, move, Is, tar, etc. We have successfully applied our working COTS Parallel Archive System to the current world's first petafiop/s computing system, LANL's Roadrunner machine, and demonstrated its capability to address

  1. How to use MPI communication in highly parallel climate simulations more easily and more efficiently.

    Science.gov (United States)

    Behrens, Jörg; Hanke, Moritz; Jahns, Thomas

    2014-05-01

    In this talk we present a way to facilitate efficient use of MPI communication for developers of climate models. Exploitation of the performance potential of today's highly parallel supercomputers with real world simulations is a complex task. This is partly caused by the low level nature of the MPI communication library which is the dominant communication tool at least for inter-node communication. In order to manage the complexity of the task, climate simulations with non-trivial communication patterns often use an internal abstraction layer above MPI without exploiting the benefits of communication aggregation or MPI-datatypes. The solution for the complexity and performance problem we propose is the communication library YAXT. This library is built on top of MPI and takes high level descriptions of arbitrary domain decompositions and automatically derives an efficient collective data exchange. Several exchanges can be aggregated in order to reduce latency costs. Examples are given which demonstrate the simplicity and the performance gains for selected climate applications.

  2. Discussion paper for a highly parallel array processor-based machine

    International Nuclear Information System (INIS)

    Hagstrom, R.; Bolotin, G.; Dawson, J.

    1984-01-01

    The architectural plant for a quickly realizable implementation of a highly parallel special-purpose computer system with peak performance in the range of 6 billion floating point operations per second is discussed. The architecture is suitable to Lattice Gauge theoretical computations of fundamental physics interest and may be applicable to a range of other problems which deal with numerically intensive computational problems. The plan is quickly realizable because it employs a maximum of commercially available hardware subsystems and because the architecture is software-transparent to the individual processors, allowing straightforward re-use of whatever commercially available operating-systems and support software that is suitable to run on the commercially-produced processors. A tiny prototype instrument, designed along this architecture has already operated. A few elementary examples of programs which can run efficiently are presented. The large machine which the authors would propose to build would be based upon a highly competent array-processor, the ST-100 Array Processor, and specific design possibilities are discussed. The first step toward realizing this plan practically is to install a single ST-100 to allow algorithm development to proceed while a demonstration unit is built using two of the ST-100 Array Processors

  3. A High-Performance Parallel FDTD Method Enhanced by Using SSE Instruction Set

    Directory of Open Access Journals (Sweden)

    Dau-Chyrh Chang

    2012-01-01

    Full Text Available We introduce a hardware acceleration technique for the parallel finite difference time domain (FDTD method using the SSE (streaming (single instruction multiple data SIMD extensions instruction set. The implementation of SSE instruction set to parallel FDTD method has achieved the significant improvement on the simulation performance. The benchmarks of the SSE acceleration on both the multi-CPU workstation and computer cluster have demonstrated the advantages of (vector arithmetic logic unit VALU acceleration over GPU acceleration. Several engineering applications are employed to demonstrate the performance of parallel FDTD method enhanced by SSE instruction set.

  4. EMG-Torque Dynamics Change With Contraction Bandwidth.

    Science.gov (United States)

    Golkar, Mahsa A; Jalaleddini, Kian; Kearney, Robert E

    2018-04-01

    An accurate model for ElectroMyoGram (EMG)-torque dynamics has many uses. One of its applications which has gained high attention among researchers is its use, in estimating the muscle contraction level for the efficient control of prosthesis. In this paper, the dynamic relationship between the surface EMG and torque during isometric contractions at the human ankle was studied using system identification techniques. Subjects voluntarily modulated their ankle torque in dorsiflexion direction, by activating their tibialis anterior muscle, while tracking a pseudo-random binary sequence in a torque matching task. The effects of contraction bandwidth, described by torque spectrum, on EMG-torque dynamics were evaluated by varying the visual command switching time. Nonparametric impulse response functions (IRF) were estimated between the processed surface EMG and torque. It was demonstrated that: 1) at low contraction bandwidths, the identified IRFs had unphysiological anticipatory (i.e., non-causal) components, whose amplitude decreased as the contraction bandwidth increased. We hypothesized that this non-causal behavior arose, because the EMG input contained a component due to feedback from the output torque, i.e., it was recorded from within a closed-loop. Vision was not the feedback source since the non-causal behavior persisted when visual feedback was removed. Repeating the identification using a nonparametric closed-loop identification algorithm yielded causal IRFs at all bandwidths, supporting this hypothesis. 2) EMG-torque dynamics became faster and the bandwidth of system increased as contraction modulation rate increased. Thus, accurate prediction of torque from EMG signals must take into account the contraction bandwidth sensitivity of this system.

  5. High fidelity thermal-hydraulic analysis using CFD and massively parallel computers

    International Nuclear Information System (INIS)

    Weber, D.P.; Wei, T.Y.C.; Brewster, R.A.; Rock, Daniel T.; Rizwan-uddin

    2000-01-01

    Thermal-hydraulic analyses play an important role in design and reload analysis of nuclear power plants. These analyses have historically relied on early generation computational fluid dynamics capabilities, originally developed in the 1960s and 1970s. Over the last twenty years, however, dramatic improvements in both computational fluid dynamics codes in the commercial sector and in computing power have taken place. These developments offer the possibility of performing large scale, high fidelity, core thermal hydraulics analysis. Such analyses will allow a determination of the conservatism employed in traditional design approaches and possibly justify the operation of nuclear power systems at higher powers without compromising safety margins. The objective of this work is to demonstrate such a large scale analysis approach using a state of the art CFD code, STAR-CD, and the computing power of massively parallel computers, provided by IBM. A high fidelity representation of a current generation PWR was analyzed with the STAR-CD CFD code and the results were compared to traditional analyses based on the VIPRE code. Current design methodology typically involves a simplified representation of the assemblies, where a single average pin is used in each assembly to determine the hot assembly from a whole core analysis. After determining this assembly, increased refinement is used in the hot assembly, and possibly some of its neighbors, to refine the analysis for purposes of calculating DNBR. This latter calculation is performed with sub-channel codes such as VIPRE. The modeling simplifications that are used involve the approximate treatment of surrounding assemblies and coarse representation of the hot assembly, where the subchannel is the lowest level of discretization. In the high fidelity analysis performed in this study, both restrictions have been removed. Within the hot assembly, several hundred thousand to several million computational zones have been used, to

  6. Mixing subattolitre volumes in a quantitative and highly parallel manner with soft matter nanofluidics

    DEFF Research Database (Denmark)

    Christensen, Sune M.; Bolinger, Pierre-Yves; Hatzakis, Nikos

    2012-01-01

    Handling and mixing ultrasmall volumes of reactants in parallel can increase the throughput and complexity of screening assays while simultaneously reducing reagent consumption. Microfabricated silicon and plastic can provide reliable fluidic devices, but cannot typically handle total volumes sma...

  7. Optimized Parallel Discrete Event Simulation (PDES) for High Performance Computing (HPC) Clusters

    National Research Council Canada - National Science Library

    Abu-Ghazaleh, Nael

    2005-01-01

    The aim of this project was to study the communication subsystem performance of state of the art optimistic simulator Synchronous Parallel Environment for Emulation and Discrete-Event Simulation (SPEEDES...

  8. High-resolution whole-brain diffusion MRI at 7T using radiofrequency parallel transmission.

    Science.gov (United States)

    Wu, Xiaoping; Auerbach, Edward J; Vu, An T; Moeller, Steen; Lenglet, Christophe; Schmitter, Sebastian; Van de Moortele, Pierre-François; Yacoub, Essa; Uğurbil, Kâmil

    2018-03-30

    Investigating the utility of RF parallel transmission (pTx) for Human Connectome Project (HCP)-style whole-brain diffusion MRI (dMRI) data at 7 Tesla (7T). Healthy subjects were scanned in pTx and single-transmit (1Tx) modes. Multiband (MB), single-spoke pTx pulses were designed to image sagittal slices. HCP-style dMRI data (i.e., 1.05-mm resolutions, MB2, b-values = 1000/2000 s/mm 2 , 286 images and 40-min scan) and data with higher accelerations (MB3 and MB4) were acquired with pTx. pTx significantly improved flip-angle detected signal uniformity across the brain, yielding ∼19% increase in temporal SNR (tSNR) averaged over the brain relative to 1Tx. This allowed significantly enhanced estimation of multiple fiber orientations (with ∼21% decrease in dispersion) in HCP-style 7T dMRI datasets. Additionally, pTx pulses achieved substantially lower power deposition, permitting higher accelerations, enabling collection of the same data in 2/3 and 1/2 the scan time or of more data in the same scan time. pTx provides a solution to two major limitations for slice-accelerated high-resolution whole-brain dMRI at 7T; it improves flip-angle uniformity, and enables higher slice acceleration relative to current state-of-the-art. As such, pTx provides significant advantages for rapid acquisition of high-quality, high-resolution truly whole-brain dMRI data. © 2018 International Society for Magnetic Resonance in Medicine.

  9. High spatial resolution whole-body MR angiography featuring parallel imaging: initial experience

    International Nuclear Information System (INIS)

    Quick, H.H.; Vogt, F.M.; Madewald, S.; Herborn, C.U.; Bosk, S.; Goehde, S.; Debatin, J.F.; Ladd, M.E.

    2004-01-01

    Materials and methods: whole-body multi-station MRA was performed with a rolling table platform (AngioSURF) on 5 volunteers in two imaging series: 1) standard imaging protocol, 2) modified high-resolution protocol employing PAT using the generalized autocalibrating partially parallel acquisitions (GRAPPA) algorithm with an acceleration factor of 3. For an intra-individual comparison of the two MR examinations, the arterial vasculature was divided into 30 segments. Signal-to-noise ratios (SNR) and contrast-to-noise ratios (CNR) were calculated for all 30 arterial segments of each subject. Vessel segment depiction was qualitatively assessed applying a 5-point scale to each of the segments. Image reconstruction times were recorded for the standard as well as the PAT protocol. Results: compared to the standard protocol, PAT allowed for increased spatial resolution through a 3-fold reduction in mean voxel size for each of the 5 stations. Mean SNR and CNR values over all specified vessel segments decreased by a factor of 1.58 and 1.56, respectively. Despite the reduced SNR and CNR, the depiction of all specified vessel segments increased in PAT images, reflecting the increased spatial resolution. Qualitative comparison of standard and PAT images showed an increase in vessel segment conspicuity with more detailed depiction of intramuscular arterial branches in all volunteers. The time for image data reconstruction of all 5 stations was significantly increased from about 10 minutes to 40 minutes when using the PAT acquisition. (orig.) [de

  10. Mathematical and numerical models to achieve high speed with special-purpose parallel processors

    International Nuclear Information System (INIS)

    Cheng, H.S.; Wulff, W.; Mallen, A.N.

    1986-01-01

    Historically, safety analyses and plant dynamic simulations have been and still are being carried out be means of detailed FORTRAN codes on expensive mainframe computers in time-consuming batch processing mode. These codes have grown to be so expensive to execute that their utilization depends increasingly on the availability of very expensive supercomputers. Thus, advanced technology for high-speed, low-cost, and accurate plant dynamic simulations is very much needed. Ideally, a low-cost facility based on a modern minicomputer can be dedicated to the staff of a power plant, which is easy and convenient to use, and which can simulate realistically plant transients at faster than real-time speeds. Such a simulation capability can enhance safety and plant utilization. One such simulation facility that has been developed is the Brookhaven National Laboratory (BNL) Plant Analyzer, currently set up for boiling water reactor plant simulations at up to seven times faster than real-time process speeds. The principal hardware components of the BNL Plant Analyzer are two units of special-purpose parallel processors, the AD10 of Applied Dynamics International and a PDP-11/34 host computer

  11. A vibrating wire parallel to a high temperature superconducting slab. Vol. 2

    Energy Technology Data Exchange (ETDEWEB)

    Saif, A G; El-sabagh, M A [Department of Mathematic and Theoretical physics, Nuclear Research Center, Atomic Energy Authority, Cairo (Egypt)

    1996-03-01

    The power losses problem for an idealized high temperature type II superconducting system of a simple geometry is studied. This system is composed of a vibrating normal conducting wire (two wires) carrying a direct current parallel to an uniaxial anisotropic type II superconducting slab (moving slab). First, the electromagnetic equation governing the dynamics of this system, and its solutions are obtained. Secondly, a modified anisotropic london equation is developed to study these systems in the case of the slab moving. Thirdly, it is found that, the power losses is dependent on the frequency, london penetration depth, permeability, conductivity, velocity, and the distance between the normal conductors and the surfaces of the superconducting slab. Moreover, the power losses decreases as the distance between the normal conductors and the surface of the superconducting slab decreases; and increases as the frequency, the london penetration depth, permeability, conductivity, and velocity are increased. These losses along the versor of the anisotropy axis is increased as {lambda}{sub |}| increases. Moreover, it is greater than the power losses along the crystal symmetry direction. In the isotropic case as well as the slab thickness tends to infinity, agreement with previous results are obtained. 2 figs.

  12. Parallel sort with a ranged, partitioned key-value store in a high perfomance computing environment

    Science.gov (United States)

    Bent, John M.; Faibish, Sorin; Grider, Gary; Torres, Aaron; Poole, Stephen W.

    2016-01-26

    Improved sorting techniques are provided that perform a parallel sort using a ranged, partitioned key-value store in a high performance computing (HPC) environment. A plurality of input data files comprising unsorted key-value data in a partitioned key-value store are sorted. The partitioned key-value store comprises a range server for each of a plurality of ranges. Each input data file has an associated reader thread. Each reader thread reads the unsorted key-value data in the corresponding input data file and performs a local sort of the unsorted key-value data to generate sorted key-value data. A plurality of sorted, ranged subsets of each of the sorted key-value data are generated based on the plurality of ranges. Each sorted, ranged subset corresponds to a given one of the ranges and is provided to one of the range servers corresponding to the range of the sorted, ranged subset. Each range server sorts the received sorted, ranged subsets and provides a sorted range. A plurality of the sorted ranges are concatenated to obtain a globally sorted result.

  13. Achieving high performance in numerical computations on RISC workstations and parallel systems

    Energy Technology Data Exchange (ETDEWEB)

    Goedecker, S. [Max-Planck Inst. for Solid State Research, Stuttgart (Germany); Hoisie, A. [Los Alamos National Lab., NM (United States)

    1997-08-20

    The nominal peak speeds of both serial and parallel computers is raising rapidly. At the same time however it is becoming increasingly difficult to get out a significant fraction of this high peak speed from modern computer architectures. In this tutorial the authors give the scientists and engineers involved in numerically demanding calculations and simulations the necessary basic knowledge to write reasonably efficient programs. The basic principles are rather simple and the possible rewards large. Writing a program by taking into account optimization techniques related to the computer architecture can significantly speedup your program, often by factors of 10--100. As such, optimizing a program can for instance be a much better solution than buying a faster computer. If a few basic optimization principles are applied during program development, the additional time needed for obtaining an efficient program is practically negligible. In-depth optimization is usually only needed for a few subroutines or kernels and the effort involved is therefore also acceptable.

  14. Parallel Adaptive Mesh Refinement for High-Order Finite-Volume Schemes in Computational Fluid Dynamics

    Science.gov (United States)

    Schwing, Alan Michael

    For computational fluid dynamics, the governing equations are solved on a discretized domain of nodes, faces, and cells. The quality of the grid or mesh can be a driving source for error in the results. While refinement studies can help guide the creation of a mesh, grid quality is largely determined by user expertise and understanding of the flow physics. Adaptive mesh refinement is a technique for enriching the mesh during a simulation based on metrics for error, impact on important parameters, or location of important flow features. This can offload from the user some of the difficult and ambiguous decisions necessary when discretizing the domain. This work explores the implementation of adaptive mesh refinement in an implicit, unstructured, finite-volume solver. Consideration is made for applying modern computational techniques in the presence of hanging nodes and refined cells. The approach is developed to be independent of the flow solver in order to provide a path for augmenting existing codes. It is designed to be applicable for unsteady simulations and refinement and coarsening of the grid does not impact the conservatism of the underlying numerics. The effect on high-order numerical fluxes of fourth- and sixth-order are explored. Provided the criteria for refinement is appropriately selected, solutions obtained using adapted meshes have no additional error when compared to results obtained on traditional, unadapted meshes. In order to leverage large-scale computational resources common today, the methods are parallelized using MPI. Parallel performance is considered for several test problems in order to assess scalability of both adapted and unadapted grids. Dynamic repartitioning of the mesh during refinement is crucial for load balancing an evolving grid. Development of the methods outlined here depend on a dual-memory approach that is described in detail. Validation of the solver developed here against a number of motivating problems shows favorable

  15. Determination of accurate 1H positions of an alanine tripeptide with anti-parallel and parallel β-sheet structures by high resolution 1H solid state NMR and GIPAW chemical shift calculation.

    Science.gov (United States)

    Yazawa, Koji; Suzuki, Furitsu; Nishiyama, Yusuke; Ohata, Takuya; Aoki, Akihiro; Nishimura, Katsuyuki; Kaji, Hironori; Shimizu, Tadashi; Asakura, Tetsuo

    2012-11-25

    The accurate (1)H positions of alanine tripeptide, A(3), with anti-parallel and parallel β-sheet structures could be determined by highly resolved (1)H DQMAS solid-state NMR spectra and (1)H chemical shift calculation with gauge-including projector augmented wave calculations.

  16. High Bandwidth, Fine Resolution Deformable Mirror Design.

    Science.gov (United States)

    1980-03-01

    Low Temperature Solders 68 B.6 Influence Function Parameters 68 APPENDIX C 19 Capacitance Measurement 69 ACCESSION for NTIS white Sectloo ODC Buff...Multilayer actuator: Dilatation versus applied electric field 10 Figure 3 - Multilayer actuator: Influence function 11 Figure 4 - Honeycomb device...bimorph 20 Figure 8 - Bimorph device: Influence function of a bimorph device which has a glass plate 0.20 cm thick 24 Figure 9 - Bimorph device

  17. Z-buffer image assembly processing in high parallel visualization processing

    International Nuclear Information System (INIS)

    Kaneko, Isamu; Muramatsu, Kazuhiro

    2000-03-01

    On the platform of the parallel computer with many processors, the domain decomposition method is used as a popular means of parallel processing. In these days when the simulation scale becomes much larger and takes a lot of time, the simultaneous visualization processing with the actual computation is much more needed, and especially in case of a real-time visualization, the domain decomposition technique is indispensable. In case of parallel rendering processing, the rendered results must be gathered to one processor to compose the integrated picture in the last stage. This integration is usually conducted by the method using Z-buffer values. This process, however, induces the crucial problems of much lower speed processing and local memory shortage in case of parallel processing exceeding more than several tens of processors. In this report, the two new solutions are proposed. The one is the adoption of a special operator (Reduce operator) in the parallelization process, and the other is a buffer compression by deleting the background informations. This report includes the performance results of these new techniques to investigate their effect with use of the parallel computer Paragon. (author)

  18. Development of three-dimensional neoclassical transport simulation code with high performance Fortran on a vector-parallel computer

    International Nuclear Information System (INIS)

    Satake, Shinsuke; Okamoto, Masao; Nakajima, Noriyoshi; Takamaru, Hisanori

    2005-11-01

    A neoclassical transport simulation code (FORTEC-3D) applicable to three-dimensional configurations has been developed using High Performance Fortran (HPF). Adoption of computing techniques for parallelization and a hybrid simulation model to the δf Monte-Carlo method transport simulation, including non-local transport effects in three-dimensional configurations, makes it possible to simulate the dynamism of global, non-local transport phenomena with a self-consistent radial electric field within a reasonable computation time. In this paper, development of the transport code using HPF is reported. Optimization techniques in order to achieve both high vectorization and parallelization efficiency, adoption of a parallel random number generator, and also benchmark results, are shown. (author)

  19. Bandwidth Widening of Piezoelectric Cantilever Beam Arrays by Mass-Tip Tuning for Low-Frequency Vibration Energy Harvesting

    Directory of Open Access Journals (Sweden)

    Eduard Dechant

    2017-12-01

    Full Text Available Wireless sensor networks usually rely on internal permanent or rechargeable batteries as a power supply, causing high maintenance efforts. An alternative solution is to supply the entire system by harvesting the ambient energy, for example, by transducing ambient vibrations into electric energy by virtue of the piezoelectric effect. The purpose of this paper is to present a simple engineering approach for the bandwidth optimization of vibration energy harvesting systems comprising multiple piezoelectric cantilevers (PECs. The frequency tuning of a particular cantilever is achieved by changing the tip mass. It is shown that the bandwidth enhancement by mass tuning is limited and requires several PECs with close resonance frequencies. At a fixed frequency detuning between subsequent PECs, the achievable bandwidth shows a saturation behavior as a function of the number of cantilevers used. Since the resonance frequency of each PEC is different, the output voltages at a particular excitation frequency have different amplitudes and phases. A simple power-transfer circuit where several PECs with an individual full wave bridge rectifier are connected in parallel allows one to extract the electrical power close to the theoretical maximum excluding the diode losses. The experiments performed on two- and three-PEC arrays show reasonable agreement with simulations and demonstrate that this power-transfer circuit additionally influences the frequency dependence of the harvested electrical power.

  20. Screening of a Brassica napus bacterial artificial chromosome library using highly parallel single nucleotide polymorphism assays

    Science.gov (United States)

    2013-01-01

    Background Efficient screening of bacterial artificial chromosome (BAC) libraries with polymerase chain reaction (PCR)-based markers is feasible provided that a multidimensional pooling strategy is implemented. Single nucleotide polymorphisms (SNPs) can be screened in multiplexed format, therefore this marker type lends itself particularly well for medium- to high-throughput applications. Combining the power of multiplex-PCR assays with a multidimensional pooling system may prove to be especially challenging in a polyploid genome. In polyploid genomes two classes of SNPs need to be distinguished, polymorphisms between accessions (intragenomic SNPs) and those differentiating between homoeologous genomes (intergenomic SNPs). We have assessed whether the highly parallel Illumina GoldenGate® Genotyping Assay is suitable for the screening of a BAC library of the polyploid Brassica napus genome. Results A multidimensional screening platform was developed for a Brassica napus BAC library which is composed of almost 83,000 clones. Intragenomic and intergenomic SNPs were included in Illumina’s GoldenGate® Genotyping Assay and both SNP classes were used successfully for screening of the multidimensional BAC pools of the Brassica napus library. An optimized scoring method is proposed which is especially valuable for SNP calling of intergenomic SNPs. Validation of the genotyping results by independent methods revealed a success of approximately 80% for the multiplex PCR-based screening regardless of whether intra- or intergenomic SNPs were evaluated. Conclusions Illumina’s GoldenGate® Genotyping Assay can be efficiently used for screening of multidimensional Brassica napus BAC pools. SNP calling was specifically tailored for the evaluation of BAC pool screening data. The developed scoring method can be implemented independently of plant reference samples. It is demonstrated that intergenomic SNPs represent a powerful tool for BAC library screening of a polyploid genome

  1. Average Bandwidth Allocation Model of WFQ

    Directory of Open Access Journals (Sweden)

    Tomáš Balogh

    2012-01-01

    Full Text Available We present a new iterative method for the calculation of average bandwidth assignment to traffic flows using a WFQ scheduler in IP based NGN networks. The bandwidth assignment calculation is based on the link speed, assigned weights, arrival rate, and average packet length or input rate of the traffic flows. We prove the model outcome with examples and simulation results using NS2 simulator.

  2. Performance studies of the parallel VIM code

    International Nuclear Information System (INIS)

    Shi, B.; Blomquist, R.N.

    1996-01-01

    In this paper, the authors evaluate the performance of the parallel version of the VIM Monte Carlo code on the IBM SPx at the High Performance Computing Research Facility at ANL. Three test problems with contrasting computational characteristics were used to assess effects in performance. A statistical method for estimating the inefficiencies due to load imbalance and communication is also introduced. VIM is a large scale continuous energy Monte Carlo radiation transport program and was parallelized using history partitioning, the master/worker approach, and p4 message passing library. Dynamic load balancing is accomplished when the master processor assigns chunks of histories to workers that have completed a previously assigned task, accommodating variations in the lengths of histories, processor speeds, and worker loads. At the end of each batch (generation), the fission sites and tallies are sent from each worker to the master process, contributing to the parallel inefficiency. All communications are between master and workers, and are serial. The SPx is a scalable 128-node parallel supercomputer with high-performance Omega switches of 63 microsec latency and 35 MBytes/sec bandwidth. For uniform and reproducible performance, they used only the 120 identical regular processors (IBM RS/6000) and excluded the remaining eight planet nodes, which may be loaded by other's jobs

  3. Parallel point-multiplication architecture using combined group operations for high-speed cryptographic applications.

    Directory of Open Access Journals (Sweden)

    Md Selim Hossain

    Full Text Available In this paper, we propose a novel parallel architecture for fast hardware implementation of elliptic curve point multiplication (ECPM, which is the key operation of an elliptic curve cryptography processor. The point multiplication over binary fields is synthesized on both FPGA and ASIC technology by designing fast elliptic curve group operations in Jacobian projective coordinates. A novel combined point doubling and point addition (PDPA architecture is proposed for group operations to achieve high speed and low hardware requirements for ECPM. It has been implemented over the binary field which is recommended by the National Institute of Standards and Technology (NIST. The proposed ECPM supports two Koblitz and random curves for the key sizes 233 and 163 bits. For group operations, a finite-field arithmetic operation, e.g. multiplication, is designed on a polynomial basis. The delay of a 233-bit point multiplication is only 3.05 and 3.56 μs, in a Xilinx Virtex-7 FPGA, for Koblitz and random curves, respectively, and 0.81 μs in an ASIC 65-nm technology, which are the fastest hardware implementation results reported in the literature to date. In addition, a 163-bit point multiplication is also implemented in FPGA and ASIC for fair comparison which takes around 0.33 and 0.46 μs, respectively. The area-time product of the proposed point multiplication is very low compared to similar designs. The performance ([Formula: see text] and Area × Time × Energy (ATE product of the proposed design are far better than the most significant studies found in the literature.

  4. A parallel calibration utility for WRF-Hydro on high performance computers

    Science.gov (United States)

    Wang, J.; Wang, C.; Kotamarthi, V. R.

    2017-12-01

    A successful modeling of complex hydrological processes comprises establishing an integrated hydrological model which simulates the hydrological processes in each water regime, calibrates and validates the model performance based on observation data, and estimates the uncertainties from different sources especially those associated with parameters. Such a model system requires large computing resources and often have to be run on High Performance Computers (HPC). The recently developed WRF-Hydro modeling system provides a significant advancement in the capability to simulate regional water cycles more completely. The WRF-Hydro model has a large range of parameters such as those in the input table files — GENPARM.TBL, SOILPARM.TBL and CHANPARM.TBL — and several distributed scaling factors such as OVROUGHRTFAC. These parameters affect the behavior and outputs of the model and thus may need to be calibrated against the observations in order to obtain a good modeling performance. Having a parameter calibration tool specifically for automate calibration and uncertainty estimates of WRF-Hydro model can provide significant convenience for the modeling community. In this study, we developed a customized tool using the parallel version of the model-independent parameter estimation and uncertainty analysis tool, PEST, to enabled it to run on HPC with PBS and SLURM workload manager and job scheduler. We also developed a series of PEST input file templates that are specifically for WRF-Hydro model calibration and uncertainty analysis. Here we will present a flood case study occurred in April 2013 over Midwest. The sensitivity and uncertainties are analyzed using the customized PEST tool we developed.

  5. A high performance data parallel tensor contraction framework: Application to coupled electro-mechanics

    Science.gov (United States)

    Poya, Roman; Gil, Antonio J.; Ortigosa, Rogelio

    2017-07-01

    The paper presents aspects of implementation of a new high performance tensor contraction framework for the numerical analysis of coupled and multi-physics problems on streaming architectures. In addition to explicit SIMD instructions and smart expression templates, the framework introduces domain specific constructs for the tensor cross product and its associated algebra recently rediscovered by Bonet et al. (2015, 2016) in the context of solid mechanics. The two key ingredients of the presented expression template engine are as follows. First, the capability to mathematically transform complex chains of operations to simpler equivalent expressions, while potentially avoiding routes with higher levels of computational complexity and, second, to perform a compile time depth-first or breadth-first search to find the optimal contraction indices of a large tensor network in order to minimise the number of floating point operations. For optimisations of tensor contraction such as loop transformation, loop fusion and data locality optimisations, the framework relies heavily on compile time technologies rather than source-to-source translation or JIT techniques. Every aspect of the framework is examined through relevant performance benchmarks, including the impact of data parallelism on the performance of isomorphic and nonisomorphic tensor products, the FLOP and memory I/O optimality in the evaluation of tensor networks, the compilation cost and memory footprint of the framework and the performance of tensor cross product kernels. The framework is then applied to finite element analysis of coupled electro-mechanical problems to assess the speed-ups achieved in kernel-based numerical integration of complex electroelastic energy functionals. In this context, domain-aware expression templates combined with SIMD instructions are shown to provide a significant speed-up over the classical low-level style programming techniques.

  6. A Fast, High Quality, and Reproducible Parallel Lagged-Fibonacci Pseudorandom Number Generator

    Science.gov (United States)

    Mascagni, Michael; Cuccaro, Steven A.; Pryor, Daniel V.; Robinson, M. L.

    1995-07-01

    We study the suitability of the additive lagged-Fibonacci pseudo-random number generator for parallel computation. This generator has relatively short period with respect to the size of its seed. However, the short period is more than made up for with the huge number of full-period cycles it contains. These different full period cycles are called equivalence classes. We show how to enumerate the equivalence classes and how to compute seeds to select a given equivalence class, In addition, we present some theoretical measures of quality for this generator when used in parallel. Next, we conjecture on the size of these measures of quality for this generator. Extensive empirical evidence supports this conjecture. In addition, a probabilistic interpretation of these measures leads to another conjecture similarly supported by empirical evidence. Finally we give an explicit parallelization suitable for a fully reproducible asynchronous MIMD implementation.

  7. Numerical investigation of power requirements for ultra-high-speed serial-to-parallel conversion

    DEFF Research Database (Denmark)

    Lillieholm, Mads; Mulvad, Hans Christian Hansen; Palushani, Evarist

    2012-01-01

    We present a numerical bit-error rate investigation of 160-640 Gbit/s serial-to-parallel conversion by four-wave mixing based time-domain optical Fourier transformation, showing an inverse scaling of the required pump energy per bit with the bit rate.......We present a numerical bit-error rate investigation of 160-640 Gbit/s serial-to-parallel conversion by four-wave mixing based time-domain optical Fourier transformation, showing an inverse scaling of the required pump energy per bit with the bit rate....

  8. 'Iconic' tracking algorithms for high energy physics using the TRAX-I massively parallel processor

    International Nuclear Information System (INIS)

    Vesztergombi, G.

    1989-01-01

    TRAX-I, a cost-effective parallel microcomputer, applying associative string processor (ASP) architecture with 16 K parallel processing elements, is being built by Aspex Microsystems Ltd. (UK). When applied to the tracking problem of very complex events with several hundred tracks, the large number of processors allows one to dedicate one or more processors to each wire (in MWPC), each pixel (in digitized images from streamer chambers or other visual detectors), or each pad (in TPC) to perform very efficient pattern recognition. Some linear tracking algorithms based on this ''ionic'' representation are presented. (orig.)

  9. 'Iconic' tracking algorithms for high energy physics using the TRAX-I massively parallel processor

    International Nuclear Information System (INIS)

    Vestergombi, G.

    1989-11-01

    TRAX-I, a cost-effective parallel microcomputer, applying Associative String Processor (ASP) architecture with 16 K parallel processing elements, is being built by Aspex Microsystems Ltd. (UK). When applied to the tracking problem of very complex events with several hundred tracks, the large number of processors allows one to dedicate one or more processors to each wire (in MWPC), each pixel (in digitized images from streamer chambers or other visual detectors), or each pad (in TPC) to perform very efficient pattern recognition. Some linear tracking algorithms based on this 'iconic' representation are presented. (orig.)

  10. Convergent Evolution of Hemoglobin Function in High-Altitude Andean Waterfowl Involves Limited Parallelism at the Molecular Sequence Level.

    Directory of Open Access Journals (Sweden)

    Chandrasekhar Natarajan

    2015-12-01

    Full Text Available A fundamental question in evolutionary genetics concerns the extent to which adaptive phenotypic convergence is attributable to convergent or parallel changes at the molecular sequence level. Here we report a comparative analysis of hemoglobin (Hb function in eight phylogenetically replicated pairs of high- and low-altitude waterfowl taxa to test for convergence in the oxygenation properties of Hb, and to assess the extent to which convergence in biochemical phenotype is attributable to repeated amino acid replacements. Functional experiments on native Hb variants and protein engineering experiments based on site-directed mutagenesis revealed the phenotypic effects of specific amino acid replacements that were responsible for convergent increases in Hb-O2 affinity in multiple high-altitude taxa. In six of the eight taxon pairs, high-altitude taxa evolved derived increases in Hb-O2 affinity that were caused by a combination of unique replacements, parallel replacements (involving identical-by-state variants with independent mutational origins in different lineages, and collateral replacements (involving shared, identical-by-descent variants derived via introgressive hybridization. In genome scans of nucleotide differentiation involving high- and low-altitude populations of three separate species, function-altering amino acid polymorphisms in the globin genes emerged as highly significant outliers, providing independent evidence for adaptive divergence in Hb function. The experimental results demonstrate that convergent changes in protein function can occur through multiple historical paths, and can involve multiple possible mutations. Most cases of convergence in Hb function did not involve parallel substitutions and most parallel substitutions did not affect Hb-O2 affinity, indicating that the repeatability of phenotypic evolution does not require parallelism at the molecular level.

  11. Sensitivity-Bandwidth Limit in a Multimode Optoelectromechanical Transducer

    Science.gov (United States)

    Moaddel Haghighi, I.; Malossi, N.; Natali, R.; Di Giuseppe, G.; Vitali, D.

    2018-03-01

    An optoelectromechanical system formed by a nanomembrane capacitively coupled to an L C resonator and to an optical interferometer has recently been employed for the highly sensitive optical readout of rf signals [T. Bagci et al., Nature (London) 507, 81 (2013), 10.1038/nature13029]. We propose and experimentally demonstrate how the bandwidth of such a transducer can be increased by controlling the interference between two electromechanical interaction pathways of a two-mode mechanical system. With a proof-of-principle device operating at room temperature, we achieve a sensitivity of 300 nV /√{Hz } over a bandwidth of 15 kHz in the presence of radio-frequency noise, and an optimal shot-noise-limited sensitivity of 10 nV /√{Hz } over a bandwidth of 5 kHz. We discuss strategies for improving the performance of the device, showing that, for the same given sensitivity, a mechanical multimode transducer can achieve a bandwidth significantly larger than that for a single-mode one.

  12. Cocaine Use and Delinquent Behavior among High-Risk Youths: A Growth Model of Parallel Processes

    Science.gov (United States)

    Dembo, Richard; Sullivan, Christopher

    2009-01-01

    We report the results of a parallel-process, latent growth model analysis examining the relationships between cocaine use and delinquent behavior among youths. The study examined a sample of 278 justice-involved juveniles completing at least one of three follow-up interviews as part of a National Institute on Drug Abuse-funded study. The results…

  13. High Performance Parallel Processing Project: Industrial computing initiative. Progress reports for fiscal year 1995

    Energy Technology Data Exchange (ETDEWEB)

    Koniges, A.

    1996-02-09

    This project is a package of 11 individual CRADA`s plus hardware. This innovative project established a three-year multi-party collaboration that is significantly accelerating the availability of commercial massively parallel processing computing software technology to U.S. government, academic, and industrial end-users. This report contains individual presentations from nine principal investigators along with overall program information.

  14. Practical parallel computing

    CERN Document Server

    Morse, H Stephen

    1994-01-01

    Practical Parallel Computing provides information pertinent to the fundamental aspects of high-performance parallel processing. This book discusses the development of parallel applications on a variety of equipment.Organized into three parts encompassing 12 chapters, this book begins with an overview of the technology trends that converge to favor massively parallel hardware over traditional mainframes and vector machines. This text then gives a tutorial introduction to parallel hardware architectures. Other chapters provide worked-out examples of programs using several parallel languages. Thi

  15. High accuracy microwave frequency measurement based on single-drive dual-parallel Mach-Zehnder modulator

    DEFF Research Database (Denmark)

    Zhao, Ying; Pang, Xiaodan; Deng, Lei

    2011-01-01

    A novel approach for broadband microwave frequency measurement by employing a single-drive dual-parallel Mach-Zehnder modulator is proposed and experimentally demonstrated. Based on bias manipulations of the modulator, conventional frequency-to-power mapping technique is developed by performing a...... 10−3 relative error. This high accuracy frequency measurement technique is a promising candidate for high-speed electronic warfare and defense applications....

  16. Passive Mobile Bandwidth Classification Using Short Lived TCP Connections

    OpenAIRE

    Michelinakis, Foivos; Kreitz, Gunnar; Petrocco, Riccardo; Zhang, Boxun; Widmer, Joerg

    2015-01-01

    Consumption of multimedia content is moving from a residential environment to mobile phones. Optimizing Quality of Experience—smooth, quick, and high quality playback—is more difficult in this setting, due to the highly dynamic nature of wireless links. A key requirement for achieving this goal is estimating the available bandwidth of mobile devices. Ideally, this should be done quickly and with low overhead. One challenge is that the majority of connections on mobiles are short-lived TCP con...

  17. Reduced bandwidth video for remote vehicle operations

    Energy Technology Data Exchange (ETDEWEB)

    Noell, T.E.; DePiero, F.W.

    1993-08-01

    Oak Ridge National Laboratory staff have developed a video compression system for low-bandwidth remote operations. The objective is to provide real-time video at data rates comparable to available tactical radio links, typically 16 to 64 thousand bits per second (kbps), while maintaining sufficient quality to achieve mission objectives. The system supports both continuous lossy transmission of black and white (gray scale) video for remote driving and progressive lossless transmission of black and white images for remote automatic target acquisition. The average data rate of the resulting bit stream is 64 kbps. This system has been demonstrated to provide video of sufficient quality to allow remote driving of a High-Mobility Multipurpose Wheeled Vehicle at speeds up to 15 mph (24.1 kph) on a moguled dirt track. The nominal driving configuration provides a frame rate of 4 Hz, a compression per frame of 125:1, and a resulting latency of {approximately}1s. This paper reviews the system approach and implementation, and further describes some of our experiences when using the system to support remote driving.

  18. A study on stimulation of DC high voltage power of LCC series parallel resonant in projectile velocity measurement system

    Science.gov (United States)

    Lu, Dong-dong; Gu, Jin-liang; Luo, Hong-e.; Xia, Yan

    2017-10-01

    According to specific requirements of the X-ray machine system for measuring velocity of outfield projectile, a DC high voltage power supply system is designed for the high voltage or the smaller current. The system comprises: a series resonant circuit is selected as a full-bridge inverter circuit; a high-frequency zero-current soft switching of a high-voltage power supply is realized by PWM output by STM32; a nanocrystalline alloy transformer is chosen as a high-frequency booster transformer; and the related parameters of an LCC series-parallel resonant are determined according to the preset parameters of the transformer. The concrete method includes: a LCC series parallel resonant circuit and a voltage doubling circuit are stimulated by using MULTISM and MATLAB; selecting an optimal solution and an optimal parameter of all parts after stimulation analysis; and finally verifying the correctness of the parameter by stimulation of the whole system. Through stimulation analysis, the output voltage of the series-parallel resonant circuit gets to 10KV in 28s: then passing through the voltage doubling circuit, the output voltage gets to 120KV in one hour. According to the system, the wave range of the output voltage is so small as to provide the stable X-ray supply for the X-ray machine for measuring velocity of outfield projectile. It is fast in charging and high in efficiency.

  19. The statistical bandwidth of Butterworth filters

    Science.gov (United States)

    Davy, J. L.; Dunn, I. P.

    1987-06-01

    The precision of standard architectural acoustic measurements is a function of the statistical bandwidth of the band pass filters used in the measurements. The International and United States Standards on octave and fractional octave-band filters which specify the band pass filters used in architectural acoustics measurements give the effective bandwidth, but unfortunately not the statistical bandwidth of the filters. Both these Standards are currently being revised and both revisions require the use of Butterworth filter characteristics. In this paper it is shown theoretically that the ratio of statistical bandwidth to effective bandwidth for an nth order Butterworth band pass filter is {2n}/{(2n-1)}. This is verified experimentally for third-octave third-order Butterworth band pass filters. It is also shown experimentally that this formula is approximately correct for some non-Butterworth third-octave third-order band pass filters. Because of the importance of Butterworth filters in the revised Standards, the theory of Butterworth filters is reviewed and the formulae for Butterworth filters given in both revised Standards are derived.

  20. GROMACS: High performance molecular simulations through multi-level parallelism from laptops to supercomputers

    Directory of Open Access Journals (Sweden)

    Mark James Abraham

    2015-09-01

    Full Text Available GROMACS is one of the most widely used open-source and free software codes in chemistry, used primarily for dynamical simulations of biomolecules. It provides a rich set of calculation types, preparation and analysis tools. Several advanced techniques for free-energy calculations are supported. In version 5, it reaches new performance heights, through several new and enhanced parallelization algorithms. These work on every level; SIMD registers inside cores, multithreading, heterogeneous CPU–GPU acceleration, state-of-the-art 3D domain decomposition, and ensemble-level parallelization through built-in replica exchange and the separate Copernicus framework. The latest best-in-class compressed trajectory storage format is supported.

  1. Highly efficient parallel direct solver for solving dense complex matrix equations from method of moments

    Directory of Open Access Journals (Sweden)

    Yan Chen

    2017-03-01

    Full Text Available Based on the vectorised and cache optimised kernel, a parallel lower upper decomposition with a novel communication avoiding pivoting scheme is developed to solve dense complex matrix equations generated by the method of moments. The fine-grain data rearrangement and assembler instructions are adopted to reduce memory accessing times and improve CPU cache utilisation, which also facilitate vectorisation of the code. Through grouping processes in a binary tree, a parallel pivoting scheme is designed to optimise the communication pattern and thus reduces the solving time of the proposed solver. Two large electromagnetic radiation problems are solved on two supercomputers, respectively, and the numerical results demonstrate that the proposed method outperforms those in open source and commercial libraries.

  2. The STAPL Parallel Graph Library

    KAUST Repository

    Harshvardhan,; Fidel, Adam; Amato, Nancy M.; Rauchwerger, Lawrence

    2013-01-01

    This paper describes the stapl Parallel Graph Library, a high-level framework that abstracts the user from data-distribution and parallelism details and allows them to concentrate on parallel graph algorithm development. It includes a customizable

  3. Scalable High-Performance Parallel Design for Network Intrusion Detection Systems on Many-Core Processors

    OpenAIRE

    Jiang, Hayang; Xie, Gaogang; Salamatian, Kavé; Mathy, Laurent

    2013-01-01

    Network Intrusion Detection Systems (NIDSes) face significant challenges coming from the relentless network link speed growth and increasing complexity of threats. Both hardware accelerated and parallel software-based NIDS solutions, based on commodity multi-core and GPU processors, have been proposed to overcome these challenges. Network Intrusion Detection Systems (NIDSes) face significant challenges coming from the relentless network link speed growth and increasing complexity of threats. ...

  4. Implementation of highly parallel and large scale GW calculations within the OpenAtom software

    Science.gov (United States)

    Ismail-Beigi, Sohrab

    The need to describe electronic excitations with better accuracy than provided by band structures produced by Density Functional Theory (DFT) has been a long-term enterprise for the computational condensed matter and materials theory communities. In some cases, appropriate theoretical frameworks have existed for some time but have been difficult to apply widely due to computational cost. For example, the GW approximation incorporates a great deal of important non-local and dynamical electronic interaction effects but has been too computationally expensive for routine use in large materials simulations. OpenAtom is an open source massively parallel ab initiodensity functional software package based on plane waves and pseudopotentials (http://charm.cs.uiuc.edu/OpenAtom/) that takes advantage of the Charm + + parallel framework. At present, it is developed via a three-way collaboration, funded by an NSF SI2-SSI grant (ACI-1339804), between Yale (Ismail-Beigi), IBM T. J. Watson (Glenn Martyna) and the University of Illinois at Urbana Champaign (Laxmikant Kale). We will describe the project and our current approach towards implementing large scale GW calculations with OpenAtom. Potential applications of large scale parallel GW software for problems involving electronic excitations in semiconductor and/or metal oxide systems will be also be pointed out.

  5. Parallel segmented outlet flow high performance liquid chromatography with multiplexed detection

    International Nuclear Information System (INIS)

    Camenzuli, Michelle; Terry, Jessica M.; Shalliker, R. Andrew; Conlan, Xavier A.; Barnett, Neil W.; Francis, Paul S.

    2013-01-01

    Graphical abstract: -- Highlights: •Multiplexed detection for liquid chromatography. •‘Parallel segmented outlet flow’ distributes inner and outer portions of the analyte zone. •Three detectors were used simultaneously for the determination of opiate alkaloids. -- Abstract: We describe a new approach to multiplex detection for HPLC, exploiting parallel segmented outlet flow – a new column technology that provides pressure-regulated control of eluate flow through multiple outlet channels, which minimises the additional dead volume associated with conventional post-column flow splitting. Using three detectors: one UV-absorbance and two chemiluminescence systems (tris(2,2′-bipyridine)ruthenium(III) and permanganate), we examine the relative responses for six opium poppy (Papaver somniferum) alkaloids under conventional and multiplexed conditions, where approximately 30% of the eluate was distributed to each detector and the remaining solution directed to a collection vessel. The parallel segmented outlet flow mode of operation offers advantages in terms of solvent consumption, waste generation, total analysis time and solute band volume when applying multiple detectors to HPLC, but the manner in which each detection system is influenced by changes in solute concentration and solution flow rates must be carefully considered

  6. Parallel segmented outlet flow high performance liquid chromatography with multiplexed detection

    Energy Technology Data Exchange (ETDEWEB)

    Camenzuli, Michelle [Australian Centre for Research on Separation Science (ACROSS), School of Science and Health, University of Western Sydney (Parramatta), Sydney, NSW (Australia); Terry, Jessica M. [Centre for Chemistry and Biotechnology, School of Life and Environmental Sciences, Deakin University, Geelong, Victoria 3216 (Australia); Shalliker, R. Andrew, E-mail: r.shalliker@uws.edu.au [Australian Centre for Research on Separation Science (ACROSS), School of Science and Health, University of Western Sydney (Parramatta), Sydney, NSW (Australia); Conlan, Xavier A.; Barnett, Neil W. [Centre for Chemistry and Biotechnology, School of Life and Environmental Sciences, Deakin University, Geelong, Victoria 3216 (Australia); Francis, Paul S., E-mail: paul.francis@deakin.edu.au [Centre for Chemistry and Biotechnology, School of Life and Environmental Sciences, Deakin University, Geelong, Victoria 3216 (Australia)

    2013-11-25

    Graphical abstract: -- Highlights: •Multiplexed detection for liquid chromatography. •‘Parallel segmented outlet flow’ distributes inner and outer portions of the analyte zone. •Three detectors were used simultaneously for the determination of opiate alkaloids. -- Abstract: We describe a new approach to multiplex detection for HPLC, exploiting parallel segmented outlet flow – a new column technology that provides pressure-regulated control of eluate flow through multiple outlet channels, which minimises the additional dead volume associated with conventional post-column flow splitting. Using three detectors: one UV-absorbance and two chemiluminescence systems (tris(2,2′-bipyridine)ruthenium(III) and permanganate), we examine the relative responses for six opium poppy (Papaver somniferum) alkaloids under conventional and multiplexed conditions, where approximately 30% of the eluate was distributed to each detector and the remaining solution directed to a collection vessel. The parallel segmented outlet flow mode of operation offers advantages in terms of solvent consumption, waste generation, total analysis time and solute band volume when applying multiple detectors to HPLC, but the manner in which each detection system is influenced by changes in solute concentration and solution flow rates must be carefully considered.

  7. A highly efficient parallel algorithm for solving the neutron diffusion nodal equations on shared-memory computers

    International Nuclear Information System (INIS)

    Azmy, Y.Y.; Kirk, B.L.

    1990-01-01

    Modern parallel computer architectures offer an enormous potential for reducing CPU and wall-clock execution times of large-scale computations commonly performed in various applications in science and engineering. Recently, several authors have reported their efforts in developing and implementing parallel algorithms for solving the neutron diffusion equation on a variety of shared- and distributed-memory parallel computers. Testing of these algorithms for a variety of two- and three-dimensional meshes showed significant speedup of the computation. Even for very large problems (i.e., three-dimensional fine meshes) executed concurrently on a few nodes in serial (nonvector) mode, however, the measured computational efficiency is very low (40 to 86%). In this paper, the authors present a highly efficient (∼85 to 99.9%) algorithm for solving the two-dimensional nodal diffusion equations on the Sequent Balance 8000 parallel computer. Also presented is a model for the performance, represented by the efficiency, as a function of problem size and the number of participating processors. The model is validated through several tests and then extrapolated to larger problems and more processors to predict the performance of the algorithm in more computationally demanding situations

  8. Bandwidth Assessment for MultiRotor UAVs

    Directory of Open Access Journals (Sweden)

    Ferrarese Gastone

    2017-06-01

    Full Text Available This paper is a technical note about the theoretical evaluation of the bandwidth of multirotor helicopters. Starting from a mathematical linear model of the dynamics of a multirotor aircraft, the transfer functions of the state variables that deeply affect the stability characteristics of the aircraft are obtained. From these transfer functions, the frequency response analysis of the system is effected. After this analysis, the bandwidth of the system is defined. This result is immediately utilized for the design of discrete PID controllers for hovering flight stabilization. Numeric simulations are shown to demonstrate that the knowledge of the bandwidth is a valid aid in the design of flight control systems of these machines.

  9. High-resolution brain SPECT imaging by combination of parallel and tilted detector heads.

    Science.gov (United States)

    Suzuki, Atsuro; Takeuchi, Wataru; Ishitsu, Takafumi; Morimoto, Yuichi; Kobashi, Keiji; Ueno, Yuichiro

    2015-10-01

    To improve the spatial resolution of brain single-photon emission computed tomography (SPECT), we propose a new brain SPECT system in which the detector heads are tilted towards the rotation axis so that they are closer to the brain. In addition, parallel detector heads are used to obtain the complete projection data set. We evaluated this parallel and tilted detector head system (PT-SPECT) in simulations. In the simulation study, the tilt angle of the detector heads relative to the axis was 45°. The distance from the collimator surface of the parallel detector heads to the axis was 130 mm. The distance from the collimator surface of the tilted detector heads to the origin on the axis was 110 mm. A CdTe semiconductor panel with a 1.4 mm detector pitch and a parallel-hole collimator were employed in both types of detector head. A line source phantom, cold-rod brain-shaped phantom, and cerebral blood flow phantom were evaluated. The projection data were generated by forward-projection of the phantom images using physics models, and Poisson noise at clinical levels was applied to the projection data. The ordered-subsets expectation maximization algorithm with physics models was used. We also evaluated conventional SPECT using four parallel detector heads for the sake of comparison. The evaluation of the line source phantom showed that the transaxial FWHM in the central slice for conventional SPECT ranged from 6.1 to 8.5 mm, while that for PT-SPECT ranged from 5.3 to 6.9 mm. The cold-rod brain-shaped phantom image showed that conventional SPECT could visualize up to 8-mm-diameter rods. By contrast, PT-SPECT could visualize up to 6-mm-diameter rods in upper slices of a cerebrum. The cerebral blood flow phantom image showed that the PT-SPECT system provided higher resolution at the thalamus and caudate nucleus as well as at the longitudinal fissure of the cerebrum compared with conventional SPECT. PT-SPECT provides improved image resolution at not only upper but also at

  10. Design and fabrication of bandwidth tunable HTS transmit filter using {pi}-shaped waveguides

    Energy Technology Data Exchange (ETDEWEB)

    Sekiya, N., E-mail: nsekiya@yamanashi.ac.j [Department of Electrical Engineering, Yamanashi University, Nakagawa-Sekiya Laboratory, 4-3-11 Takeda, Kofu 400-8511 (Japan); Harada, H.; Nakagawa, Y. [Department of Electrical Engineering, Yamanashi University, Nakagawa-Sekiya Laboratory, 4-3-11 Takeda, Kofu 400-8511 (Japan); Ono, S.; Ohshima, S. [Yamagata University, 4-3-16 Johnan, Yonezawa 992-8510 (Japan)

    2010-11-01

    We have developed a method for tuning the bandwidth of a high-temperature superconducting (HTS) microstrip filter. Several {pi}-shaped waveguides are placed between the resonators, and the bandwidth is tuned in discrete steps by changing the switch states of the waveguides, which changes the coupling coefficient between the resonators. The filter contains 3-pole half-wavelength straight-line resonators and two {pi}-shaped waveguides for bandwidth tuning. It also has several electrical pads distributed around the feed lines for trimming after tuning. The filter was fabricated by depositing YBa{sub 2}Cu{sub 3}O{sub 7} thin film on an MgO substrate and has a measured center frequency of 5.17 GHz and bandwidth of 220 MHz. Use of the {pi}-shaped waveguides to adjust the coupling coefficients and the electrical pads to adjust the external quality factors resulted in 80-MHz bandwidth tuning without increased insertion loss.

  11. Parallel R

    CERN Document Server

    McCallum, Ethan

    2011-01-01

    It's tough to argue with R as a high-quality, cross-platform, open source statistical software product-unless you're in the business of crunching Big Data. This concise book introduces you to several strategies for using R to analyze large datasets. You'll learn the basics of Snow, Multicore, Parallel, and some Hadoop-related tools, including how to find them, how to use them, when they work well, and when they don't. With these packages, you can overcome R's single-threaded nature by spreading work across multiple CPUs, or offloading work to multiple machines to address R's memory barrier.

  12. Bandwidth Reservations in Home Networks

    DEFF Research Database (Denmark)

    Nelis, Jelle; Verslype, Dieter; Develder, Chris

    2010-01-01

    In order for service providers to provide their users high quality services in the home network, Quality of Service (QoS) provisioning is needed to protect premium services. In this paper, we describe how a Universal Plug-and-Play (UPnP) based home network architecture solves this problem...... in a heterogeneous home network. We outline how it both relieves the end user from troublesome configuration and still offers control to the service provider. We particularly present performance assessment results for UPnP-QoS v3, based on a fully operational experimental implementation. The quantitative measurement...

  13. A high-quality narrow passband filter for elastic SV waves via aligned parallel separated thin polymethylmethacrylate plates

    OpenAIRE

    Jun Zhang; Yaolu Liu; Wensheng Yan; Ning Hu

    2017-01-01

    We designed a high-quality filter that consists of aligned parallel polymethylmethacrylate (PMMA) thin plates with small gaps for elastic SV waves propagate in metals. Both the theoretical model and the full numerical simulation show the transmission spectrum of the elastic SV waves through such a filter has several sharp peaks with flawless transmission within the investigated frequencies. These peaks can be readily tuned by manipulating the geometry parameters of the PMMA plates. Our invest...

  14. Approaches for introducing high molecular diversity in scaffolds: fast parallel synthesis of highly substituted 1H-quinolin-4-one libraries.

    Science.gov (United States)

    Kuznetsov, Vladimir; Gorohovsky, Sofia; Levy, Amalia; Meir, Simcha; Shkoulev, Vladimir; Menashe, Naim; Greenwald, Moshe; Aizikovich, Alexander; Ofer, Dror; Byk, Gerardo; Gellerman, Garry

    2004-01-01

    We have developed a two steps strategy for the parallel synthesis of highly diversified quinolin-ones. In the first step we have combined and improved different synthetic methods for generating quinolin-4-ones bearing four different substitutions at specific positions using round bottomed flasks. The synthesis was assessed for a large number of substituted quinolin-4-ones. In the second step, the improved method was adapted to a parallel array synthesis using a 12 positions carrousel as demonstrated for the synthesis of 42-variable quinolin-4-ones. The first combinatorial library set 14(a-x) was obtained with a chemical purity of more than 95% without purification, the second library set 15(a-r), which included two synthetic steps, needed combinatorial purification using an innovative parallel purifier. The proposed approach contributes to a more extensive diversification of molecular scaffolds in general and provides access to highly substituted quinolinones in particular.

  15. Convergence of highly parallel stray field calculation using the fast multipole method on irregular meshes

    Science.gov (United States)

    Palmesi, P.; Abert, C.; Bruckner, F.; Suess, D.

    2018-05-01

    Fast stray field calculation is commonly considered of great importance for micromagnetic simulations, since it is the most time consuming part of the simulation. The Fast Multipole Method (FMM) has displayed linear O(N) parallelization behavior on many cores. This article investigates the error of a recent FMM approach approximating sources using linear—instead of constant—finite elements in the singular integral for calculating the stray field and the corresponding potential. After measuring performance in an earlier manuscript, this manuscript investigates the convergence of the relative L2 error for several FMM simulation parameters. Various scenarios either calculating the stray field directly or via potential are discussed.

  16. High temporal resolution magnetic resonance imaging: development of a parallel three dimensional acquisition method for functional neuroimaging

    International Nuclear Information System (INIS)

    Rabrait, C.

    2007-11-01

    Echo Planar Imaging is widely used to perform data acquisition in functional neuroimaging. This sequence allows the acquisition of a set of about 30 slices, covering the whole brain, at a spatial resolution ranging from 2 to 4 mm, and a temporal resolution ranging from 1 to 2 s. It is thus well adapted to the mapping of activated brain areas but does not allow precise study of the brain dynamics. Moreover, temporal interpolation is needed in order to correct for inter-slices delays and 2-dimensional acquisition is subject to vascular in flow artifacts. To improve the estimation of the hemodynamic response functions associated with activation, this thesis aimed at developing a 3-dimensional high temporal resolution acquisition method. To do so, Echo Volume Imaging was combined with reduced field-of-view acquisition and parallel imaging. Indeed, E.V.I. allows the acquisition of a whole volume in Fourier space following a single excitation, but it requires very long echo trains. Parallel imaging and field-of-view reduction are used to reduce the echo train durations by a factor of 4, which allows the acquisition of a 3-dimensional brain volume with limited susceptibility-induced distortions and signal losses, in 200 ms. All imaging parameters have been optimized in order to reduce echo train durations and to maximize S.N.R., so that cerebral activation can be detected with a high level of confidence. Robust detection of brain activation was demonstrated with both visual and auditory paradigms. High temporal resolution hemodynamic response functions could be estimated through selective averaging of the response to the different trials of the stimulation. To further improve S.N.R., the matrix inversions required in parallel reconstruction were regularized, and the impact of the level of regularization on activation detection was investigated. Eventually, potential applications of parallel E.V.I. such as the study of non-stationary effects in the B.O.L.D. response

  17. Experience with highly-parallel software for the storage system of the ATLAS Experiment at CERN

    CERN Document Server

    Colombo, T; The ATLAS collaboration

    2012-01-01

    The ATLAS experiment is observing proton-proton collisions delivered by the LHC accelerator. The ATLAS Trigger and Data Acquisition (TDAQ) system selects interesting events on-line in a three-level trigger system in order to store them at a budgeted rate of several hundred Hz. This paper focuses on the TDAQ data-logging system and in particular on the implementation and performance of a novel parallel software design. In this respect, the main challenge presented by the data-logging workload is the conflict between the largely parallel nature of the event processing, especially the recently introduced event compression, and the constraint of sequential file writing and checksum evaluation. This is further complicated by the necessity of operating in a fully data-driven mode, to cope with continuously evolving trigger and detector configurations. In this paper we report on the design of the new ATLAS on-line storage software. In particular we will discuss our development experience using recent concurrency-ori...

  18. H5Part A Portable High Performance Parallel Data Interface for Particle Simulations

    CERN Document Server

    Adelmann, Andreas; Shalf, John M; Siegerist, Cristina

    2005-01-01

    Largest parallel particle simulations, in six dimensional phase space generate wast amont of data. It is also desirable to share data and data analysis tools such as ParViT (Particle Visualization Toolkit) among other groups who are working on particle-based accelerator simulations. We define a very simple file schema built on top of HDF5 (Hierarchical Data Format version 5) as well as an API that simplifies the reading/writing of the data to the HDF5 file format. HDF5 offers a self-describing machine-independent binary file format that supports scalable parallel I/O performance for MPI codes on a variety of supercomputing systems and works equally well on laptop computers. The API is available for C, C++, and Fortran codes. The file format will enable disparate research groups with very different simulation implementations to share data transparently and share data analysis tools. For instance, the common file format will enable groups that depend on completely different simulation implementations to share c...

  19. Digital demodulator for wide bandwidth SAR

    DEFF Research Database (Denmark)

    Jørgensen, Jørn Hjelm

    2000-01-01

    A novel approach to the design of efficient digital quadrature demodulators for wide bandwidth SAR systems is described. Efficiency is obtained by setting the intermediate frequency to 1/4 the ADC sampling frequency. One channel is made filter-free by synchronizing the local oscillator...

  20. Experiences in Traceroute and Bandwidth Change Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Logg, C

    2004-06-23

    SLAC has been studying end-to-end WAN bandwidth availability and achievability for 2.5 years via IEPM-BW [1]. IEPM-BW performs network intensive tests every 90 minutes. Based on that experience we have also developed a light weight available bandwidth (ABwE [2]) measurement tool that can make a measurement within a second. We are now extending this to a WAN measurement and detection system (IEPM-LITE) aimed at more quickly detecting and troubleshooting network performance problems and also to be more friendly on lower performance paths. IEPM-LITE uses ping, forward traceroutes, and ABwE sensors to monitor, in close to real-time, Round Trip Times (RTT), changes in available bandwidth and routes to and from target hosts. This paper discusses the experiences, techniques and algorithms used to detect and report on significant traceroute and bandwidth changes. The ultimate aim is to develop a lightweight WAN network performance monitoring system that can detect, in near real time, significant changes and generate alerts.

  1. Experiences in Traceroute and Bandwidth Change Analysis

    International Nuclear Information System (INIS)

    Logg, C

    2004-01-01

    SLAC has been studying end-to-end WAN bandwidth availability and achievability for 2.5 years via IEPM-BW [1]. IEPM-BW performs network intensive tests every 90 minutes. Based on that experience we have also developed a light weight available bandwidth (ABwE [2]) measurement tool that can make a measurement within a second. We are now extending this to a WAN measurement and detection system (IEPM-LITE) aimed at more quickly detecting and troubleshooting network performance problems and also to be more friendly on lower performance paths. IEPM-LITE uses ping, forward traceroutes, and ABwE sensors to monitor, in close to real-time, Round Trip Times (RTT), changes in available bandwidth and routes to and from target hosts. This paper discusses the experiences, techniques and algorithms used to detect and report on significant traceroute and bandwidth changes. The ultimate aim is to develop a lightweight WAN network performance monitoring system that can detect, in near real time, significant changes and generate alerts

  2. Improved space bandwidth product in image upconversion

    DEFF Research Database (Denmark)

    Dam, Jeppe Seidelin; Pedersen, Christian; Tidemand-Lichtenberg, Peter

    2012-01-01

    We present a technique increasing the space bandwidth product of a nonlinear image upconversion process used for spectral imaging. The technique exploits the strong dependency of the phase-matching condition in sum frequency generation (SFG) on the angle of propagation of the interacting fields...

  3. A comparison of high-order explicit Runge–Kutta, extrapolation, and deferred correction methods in serial and parallel

    KAUST Repository

    Ketcheson, David I.

    2014-06-13

    We compare the three main types of high-order one-step initial value solvers: extrapolation, spectral deferred correction, and embedded Runge–Kutta pairs. We consider orders four through twelve, including both serial and parallel implementations. We cast extrapolation and deferred correction methods as fixed-order Runge–Kutta methods, providing a natural framework for the comparison. The stability and accuracy properties of the methods are analyzed by theoretical measures, and these are compared with the results of numerical tests. In serial, the eighth-order pair of Prince and Dormand (DOP8) is most efficient. But other high-order methods can be more efficient than DOP8 when implemented in parallel. This is demonstrated by comparing a parallelized version of the wellknown ODEX code with the (serial) DOP853 code. For an N-body problem with N = 400, the experimental extrapolation code is as fast as the tuned Runge–Kutta pair at loose tolerances, and is up to two times as fast at tight tolerances.

  4. Conceptual design and kinematic analysis of a novel parallel robot for high-speed pick-and-place operations

    Science.gov (United States)

    Meng, Qizhi; Xie, Fugui; Liu, Xin-Jun

    2018-06-01

    This paper deals with the conceptual design, kinematic analysis and workspace identification of a novel four degrees-of-freedom (DOFs) high-speed spatial parallel robot for pick-and-place operations. The proposed spatial parallel robot consists of a base, four arms and a 1½ mobile platform. The mobile platform is a major innovation that avoids output singularity and offers the advantages of both single and double platforms. To investigate the characteristics of the robot's DOFs, a line graph method based on Grassmann line geometry is adopted in mobility analysis. In addition, the inverse kinematics is derived, and the constraint conditions to identify the correct solution are also provided. On the basis of the proposed concept, the workspace of the robot is identified using a set of presupposed parameters by taking input and output transmission index as the performance evaluation criteria.

  5. libstable: Fast, Parallel, and High-Precision Computation of α-Stable Distributions in R, C/C++, and MATLAB

    Directory of Open Access Journals (Sweden)

    Javier Royuela-del-Val

    2017-06-01

    Full Text Available α-stable distributions are a family of well-known probability distributions. However, the lack of closed analytical expressions hinders their application. Currently, several tools have been developed to numerically evaluate their density and distribution functions or to estimate their parameters, but available solutions either do not reach sufficient precision on their evaluations or are excessively slow for practical purposes. Moreover, they do not take full advantage of the parallel processing capabilities of current multi-core machines. Other solutions work only on a subset of the α-stable parameter space. In this paper we present an R package and a C/C++ library with a MATLAB front-end that permit parallelized, fast and high precision evaluation of density, distribution and quantile functions, as well as random variable generation and parameter estimation of α-stable distributions in their whole parameter space. The described library can be easily integrated into third party developments.

  6. High performance shallow water kernels for parallel overland flow simulations based on FullSWOF2D

    KAUST Repository

    Wittmann, Roland

    2017-01-25

    We describe code optimization and parallelization procedures applied to the sequential overland flow solver FullSWOF2D. Major difficulties when simulating overland flows comprise dealing with high resolution datasets of large scale areas which either cannot be computed on a single node either due to limited amount of memory or due to too many (time step) iterations resulting from the CFL condition. We address these issues in terms of two major contributions. First, we demonstrate a generic step-by-step transformation of the second order finite volume scheme in FullSWOF2D towards MPI parallelization. Second, the computational kernels are optimized by the use of templates and a portable vectorization approach. We discuss the load imbalance of the flux computation due to dry and wet cells and propose a solution using an efficient cell counting approach. Finally, scalability results are shown for different test scenarios along with a flood simulation benchmark using the Shaheen II supercomputer.

  7. Parallel processing method for high-speed real time digital pulse processing for gamma-ray spectroscopy

    International Nuclear Information System (INIS)

    Fernandes, A.M.; Pereira, R.C.; Sousa, J.; Neto, A.; Carvalho, P.; Batista, A.J.N.; Carvalho, B.B.; Varandas, C.A.F.; Tardocchi, M.; Gorini, G.

    2010-01-01

    A new data acquisition (DAQ) system was developed to fulfil the requirements of the gamma-ray spectrometer (GRS) JET-EP2 (joint European Torus enhancement project 2), providing high-resolution spectroscopy at very high-count rate (up to few MHz). The system is based on the Advanced Telecommunications Computing Architecture TM (ATCA TM ) and includes a transient record (TR) module with 8 channels of 14 bits resolution at 400 MSamples/s (MSPS) sampling rate, 4 GB of local memory, and 2 field programmable gate array (FPGA) able to perform real time algorithms for data reduction and digital pulse processing. Although at 400 MSPS only fast programmable devices such as FPGAs can be used either for data processing and data transfer, FPGA resources also present speed limitation at some specific tasks, leading to an unavoidable data lost when demanding algorithms are applied. To overcome this problem and foreseeing an increase of the algorithm complexity, a new digital parallel filter was developed, aiming to perform real time pulse processing in the FPGAs of the TR module at the presented sampling rate. The filter is based on the conventional digital time-invariant trapezoidal shaper operating with parallelized data while performing pulse height analysis (PHA) and pile up rejection (PUR). The incoming sampled data is successively parallelized and fed into the processing algorithm block at one fourth of the sampling rate. The following data processing and data transfer is also performed at one fourth of the sampling rate. The algorithm based on data parallelization technique was implemented and tested at JET facilities, where a spectrum was obtained. Attending to the observed results, the PHA algorithm will be improved by implementing the pulse pile up discrimination.

  8. Extending molecular simulation time scales: Parallel in time integrations for high-level quantum chemistry and complex force representations

    Energy Technology Data Exchange (ETDEWEB)

    Bylaska, Eric J., E-mail: Eric.Bylaska@pnnl.gov [Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352 (United States); Weare, Jonathan Q., E-mail: weare@uchicago.edu [Department of Mathematics, University of Chicago, Chicago, Illinois 60637 (United States); Weare, John H., E-mail: jweare@ucsd.edu [Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093 (United States)

    2013-08-21

    to 14.3. The parallel in time algorithms can be implemented in a distributed computing environment using very slow transmission control protocol/Internet protocol networks. Scripts written in Python that make calls to a precompiled quantum chemistry package (NWChem) are demonstrated to provide an actual speedup of 8.2 for a 2.5 ps AIMD simulation of HCl + 4H{sub 2}O at the MP2/6-31G* level. Implemented in this way these algorithms can be used for long time high-level AIMD simulations at a modest cost using machines connected by very slow networks such as WiFi, or in different time zones connected by the Internet. The algorithms can also be used with programs that are already parallel. Using these algorithms, we are able to reduce the cost of a MP2/6-311++G(2d,2p) simulation that had reached its maximum possible speedup in the parallelization of the electronic structure calculation from 32 s/time step to 6.9 s/time step.

  9. Extending molecular simulation time scales: Parallel in time integrations for high-level quantum chemistry and complex force representations

    International Nuclear Information System (INIS)

    Bylaska, Eric J.; Weare, Jonathan Q.; Weare, John H.

    2013-01-01

    distributed computing environment using very slow transmission control protocol/Internet protocol networks. Scripts written in Python that make calls to a precompiled quantum chemistry package (NWChem) are demonstrated to provide an actual speedup of 8.2 for a 2.5 ps AIMD simulation of HCl + 4H 2 O at the MP2/6-31G* level. Implemented in this way these algorithms can be used for long time high-level AIMD simulations at a modest cost using machines connected by very slow networks such as WiFi, or in different time zones connected by the Internet. The algorithms can also be used with programs that are already parallel. Using these algorithms, we are able to reduce the cost of a MP2/6-311++G(2d,2p) simulation that had reached its maximum possible speedup in the parallelization of the electronic structure calculation from 32 s/time step to 6.9 s/time step

  10. Quartic scaling MP2 for solids: A highly parallelized algorithm in the plane wave basis

    Science.gov (United States)

    Schäfer, Tobias; Ramberger, Benjamin; Kresse, Georg

    2017-03-01

    We present a low-complexity algorithm to calculate the correlation energy of periodic systems in second-order Møller-Plesset (MP2) perturbation theory. In contrast to previous approximation-free MP2 codes, our implementation possesses a quartic scaling, O ( N 4 ) , with respect to the system size N and offers an almost ideal parallelization efficiency. The general issue that the correlation energy converges slowly with the number of basis functions is eased by an internal basis set extrapolation. The key concept to reduce the scaling is to eliminate all summations over virtual orbitals which can be elegantly achieved in the Laplace transformed MP2 formulation using plane wave basis sets and fast Fourier transforms. Analogously, this approach could allow us to calculate second order screened exchange as well as particle-hole ladder diagrams with a similar low complexity. Hence, the presented method can be considered as a step towards systematically improved correlation energies.

  11. Stochastic parallel gradient descent based adaptive optics used for a high contrast imaging coronagraph

    International Nuclear Information System (INIS)

    Dong Bing; Ren Deqing; Zhang Xi

    2011-01-01

    An adaptive optics (AO) system based on a stochastic parallel gradient descent (SPGD) algorithm is proposed to reduce the speckle noises in the optical system of a stellar coronagraph in order to further improve the contrast. The principle of the SPGD algorithm is described briefly and a metric suitable for point source imaging optimization is given. The feasibility and good performance of the SPGD algorithm is demonstrated by an experimental system featured with a 140-actuator deformable mirror and a Hartmann-Shark wavefront sensor. Then the SPGD based AO is applied to a liquid crystal array (LCA) based coronagraph to improve the contrast. The LCA can modulate the incoming light to generate a pupil apodization mask of any pattern. A circular stepped pattern is used in our preliminary experiment and the image contrast shows improvement from 10 -3 to 10 -4.5 at an angular distance of 2λ/D after being corrected by SPGD based AO.

  12. Kernel bandwidth estimation for non-parametric density estimation: a comparative study

    CSIR Research Space (South Africa)

    Van der Walt, CM

    2013-12-01

    Full Text Available We investigate the performance of conventional bandwidth estimators for non-parametric kernel density estimation on a number of representative pattern-recognition tasks, to gain a better understanding of the behaviour of these estimators in high...

  13. Research on the verification of highly parallel and concurrent embedded software

    OpenAIRE

    青木, 利晃

    2012-01-01

    本研究では,スケジューリングを伴う並行・並列ソフトウェアと,スケジューリングを提供するリアルタイムオペレーティングシステム(RTOS)を対象とした.成果としては,前者に関しては,実時間を含む振る舞いを検証するためのアルゴリズムおよびツールを提案し,後者に関しては,RTOS の設計と実装を検証する手法およびツールを提案し,実際に使われているRTOS の検証も行った.これにより,現実的なセッティングで,モデル検査に基づいた手法の提案に成功し,実際に,現実問題に適用できることがわかった. : We focus on parallel/concurrent software which is controlled by real-time operating system(RTOS) and RTOS itself. We have proposed an algorithm and tool to verify the behavior of parallel/concurrent software which contains scheduling by RTOS and real-...

  14. Unique parallel radiations of high-mountainous species of the genus Sedum (Crassulaceae) on the continental island of Taiwan.

    Science.gov (United States)

    Ito, Takuro; Yu, Chih-Chieh; Nakamura, Koh; Chung, Kuo-Fang; Yang, Qin-Er; Fu, Cheng-Xin; Qi, Zhe-Chen; Kokubugata, Goro

    2017-08-01

    We explored the temporal and spatial diversification of the plant genus Sedum L. (Crassulaceae) in Taiwan based on molecular analysis of nrITS and cpDNA sequences from East Asian Sedum members. Our phylogenetic and ancestral area reconstruction analysis showed that Taiwanese Sedum comprised two lineages that independently migrated from Japan and Eastern China. Furthermore, the genetic distances among species in these two clades were smaller than those of other East Asian Sedum clades, and the Taiwanese members of each clade occupy extremely varied habitats with similar niches in high-mountain regions. These data indicate that species diversification occurred in parallel in the two Taiwanese Sedum lineages, and that these parallel radiations could have occurred within the small continental island of Taiwan. Moreover, the estimated time of divergence for Taiwanese Sedum indicates that the two radiations might have been correlated to the formation of mountains in Taiwan during the early Pleistocene. We suggest that these parallel radiations may be attributable to the geographical dynamics of Taiwan and specific biological features of Sedum that allow them to adapt to new ecological niches. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Optimization of Quantum-Dot Molecular Beam Epitaxy for Broad Spectral Bandwidth Devices

    KAUST Repository

    Majid, Mohammed Abdul

    2012-12-01

    The optimization of the key growth parameters for broad spectral bandwidth devices based on quantum dots is reported. A combination of atomic force microscopy, photoluminescence of test samples, and optoelectronic characterization of superluminescent diodes (SLDs) is used to optimize the growth conditions to obtain high-quality devices with large spectral bandwidth, radiative efficiency (due to a reduced defective-dot density), and thus output power. The defective-dot density is highlighted as being responsible for the degradation of device performance. An SLD device with 160 nm of bandwidth centered at 1230 nm is demonstrated.

  16. Optimization of Quantum-Dot Molecular Beam Epitaxy for Broad Spectral Bandwidth Devices

    KAUST Repository

    Majid, Mohammed Abdul; Hugues, M.; Vézian, S.; Childs, D. T. D.; Hogg, R. A.

    2012-01-01

    The optimization of the key growth parameters for broad spectral bandwidth devices based on quantum dots is reported. A combination of atomic force microscopy, photoluminescence of test samples, and optoelectronic characterization of superluminescent diodes (SLDs) is used to optimize the growth conditions to obtain high-quality devices with large spectral bandwidth, radiative efficiency (due to a reduced defective-dot density), and thus output power. The defective-dot density is highlighted as being responsible for the degradation of device performance. An SLD device with 160 nm of bandwidth centered at 1230 nm is demonstrated.

  17. Analysis and design of a parallel-connected single active bridge DC-DC converter for high-power wind farm applications

    DEFF Research Database (Denmark)

    Park, Kiwoo; Chen, Zhe

    2013-01-01

    This paper presents a parallel-connected Single Active Bridge (SAB) dc-dc converter for high-power applications. Paralleling lower-power converters can lower the current rating of each modular converter and interleaving the outputs can significantly reduce the magnitudes of input and output curre...

  18. Bandwidth-sharing in LHCONE, an analysis of the problem

    Science.gov (United States)

    Wildish, T.

    2015-12-01

    The LHC experiments have traditionally regarded the network as an unreliable resource, one which was expected to be a major source of errors and inefficiency at the time their original computing models were derived. Now, however, the network is seen as much more capable and reliable. Data are routinely transferred with high efficiency and low latency to wherever computing or storage resources are available to use or manage them. Although there was sufficient network bandwidth for the experiments’ needs during Run-1, they cannot rely on ever-increasing bandwidth as a solution to their data-transfer needs in the future. Sooner or later they need to consider the network as a finite resource that they interact with to manage their traffic, in much the same way as they manage their use of disk and CPU resources. There are several possible ways for the experiments to integrate management of the network in their software stacks, such as the use of virtual circuits with hard bandwidth guarantees or soft real-time flow-control, with somewhat less firm guarantees. Abstractly, these can all be considered as the users (the experiments, or groups of users within the experiment) expressing a request for a given bandwidth between two points for a given duration of time. The network fabric then grants some allocation to each user, dependent on the sum of all requests and the sum of available resources, and attempts to ensure the requirements are met (either deterministically or statistically). An unresolved question at this time is how to convert the users’ requests into an allocation. Simply put, how do we decide what fraction of a network's bandwidth to allocate to each user when the sum of requests exceeds the available bandwidth? The usual problems of any resourcescheduling system arise here, namely how to ensure the resource is used efficiently and fairly, while still satisfying the needs of the users. Simply fixing quotas on network paths for each user is likely to lead

  19. Extending molecular simulation time scales: Parallel in time integrations for high-level quantum chemistry and complex force representations.

    Science.gov (United States)

    Bylaska, Eric J; Weare, Jonathan Q; Weare, John H

    2013-08-21

    distributed computing environment using very slow transmission control protocol/Internet protocol networks. Scripts written in Python that make calls to a precompiled quantum chemistry package (NWChem) are demonstrated to provide an actual speedup of 8.2 for a 2.5 ps AIMD simulation of HCl + 4H2O at the MP2/6-31G* level. Implemented in this way these algorithms can be used for long time high-level AIMD simulations at a modest cost using machines connected by very slow networks such as WiFi, or in different time zones connected by the Internet. The algorithms can also be used with programs that are already parallel. Using these algorithms, we are able to reduce the cost of a MP2/6-311++G(2d,2p) simulation that had reached its maximum possible speedup in the parallelization of the electronic structure calculation from 32 s/time step to 6.9 s/time step.

  20. Cpl6: The New Extensible, High-Performance Parallel Coupler forthe Community Climate System Model

    Energy Technology Data Exchange (ETDEWEB)

    Craig, Anthony P.; Jacob, Robert L.; Kauffman, Brain; Bettge,Tom; Larson, Jay; Ong, Everest; Ding, Chris; He, Yun

    2005-03-24

    Coupled climate models are large, multiphysics applications designed to simulate the Earth's climate and predict the response of the climate to any changes in the forcing or boundary conditions. The Community Climate System Model (CCSM) is a widely used state-of-art climate model that has released several versions to the climate community over the past ten years. Like many climate models, CCSM employs a coupler, a functional unit that coordinates the exchange of data between parts of climate system such as the atmosphere and ocean. This paper describes the new coupler, cpl6, contained in the latest version of CCSM,CCSM3. Cpl6 introduces distributed-memory parallelism to the coupler, a class library for important coupler functions, and a standardized interface for component models. Cpl6 is implemented entirely in Fortran90 and uses Model Coupling Toolkit as the base for most of its classes. Cpl6 gives improved performance over previous versions and scales well on multiple platforms.

  1. Parallel Adjective High-Order CFD Simulations Characterizing SOFIA Cavity Acoustics

    Science.gov (United States)

    Barad, Michael F.; Brehm, Christoph; Kiris, Cetin C.; Biswas, Rupak

    2016-01-01

    This paper presents large-scale MPI-parallel computational uid dynamics simulations for the Stratospheric Observatory for Infrared Astronomy (SOFIA). SOFIA is an airborne, 2.5-meter infrared telescope mounted in an open cavity in the aft fuselage of a Boeing 747SP. These simulations focus on how the unsteady ow eld inside and over the cavity interferes with the optical path and mounting structure of the telescope. A temporally fourth-order accurate Runge-Kutta, and spatially fth-order accurate WENO- 5Z scheme was used to perform implicit large eddy simulations. An immersed boundary method provides automated gridding for complex geometries and natural coupling to a block-structured Cartesian adaptive mesh re nement framework. Strong scaling studies using NASA's Pleiades supercomputer with up to 32k CPU cores and 4 billion compu- tational cells shows excellent scaling. Dynamic load balancing based on execution time on individual AMR blocks addresses irregular numerical cost associated with blocks con- taining boundaries. Limits to scaling beyond 32k cores are identi ed, and targeted code optimizations are discussed.

  2. Scattering by a plane-parallel layer with high concentration of optically soft particles

    International Nuclear Information System (INIS)

    Loiko, Valery A.; Berdnik, Vladimir V.

    2009-01-01

    A method describing light propagation in a plane-parallel light-scattering layer with large concentration of homogeneous particles is developed. It is based on the radiative transfer equation and the doubling method. The interference approximation is used to take into account collective scattering effects. Spectral dependence of transmitted light for a layer of nonabsorbing optically soft particles with subwavelength-sized particles is investigated. At small volume concentration of the particles the weak spectral dependences of wave exponents for coherently transmitted and diffuse light are observed. It is shown that in a layer with large volume concentration of the subwavelength-sized particles the wave exponent can exceed considerably the value of four, which takes place for the Rayleigh particles. The dependence of wave exponents for coherently transmitted and diffuse light on the refractive index and concentration of particles is investigated in detail. Multiple scattering of light results in the reduction of the exponent. The quantitative results are presented and discussed. It is shown that there is a range of wavelengths where the negative values of the wave exponent at the regime of multiple scattering are implemented.

  3. Experience with highly-parallel software for the storage system of the ATLAS Experiment at CERN

    CERN Document Server

    Colombo, T; The ATLAS collaboration

    2012-01-01

    The ATLAS experiment is observing proton-proton collisions delivered by the LHC accelerator at a centre of mass energy of 7 TeV. The ATLAS Trigger and Data Acquisition (TDAQ) system selects interesting events on-line in a three-level trigger system in order to store them at a budgeted rate of several hundred Hz, for an average event size of ~1.2 MB. This paper focuses on the TDAQ data-logging system and in particular on the implementation and performance of a novel SW design, reporting on the effort of exploiting the full power of recently installed multi-core hardware. In this respect, the main challenge presented by the data-logging workload is the conflict between the largely parallel nature of the event processing, especially the recently introduced on-line event-compression, and the constraint of sequential file writing and checksum evaluation. This is furtherly complicated by the necessity of operating in a fully data-driven mode, to cope with continuously evolving trigger and detector configurations. T...

  4. Large-bandwidth planar photonic crystal waveguides

    DEFF Research Database (Denmark)

    Søndergaard, Thomas; Lavrinenko, Andrei

    2002-01-01

    A general design principle is presented for making finite-height photonic crystal waveguides that support leakage-free guidance of light over large frequency intervals. The large bandwidth waveguides are designed by introducing line defects in photonic crystal slabs, where the material in the line...... defect has appropriate dispersion properties relative to the photonic crystal slab material surrounding the line defect. A three-dimensional theoretical analysis is given for large-bandwidth waveguide designs based on a silicon-air photonic crystal slab suspended in air. In one example, the leakage......-free single-mode guidance is found for a large frequency interval covering 60% of the photonic band-gap....

  5. Parallel rendering

    Science.gov (United States)

    Crockett, Thomas W.

    1995-01-01

    This article provides a broad introduction to the subject of parallel rendering, encompassing both hardware and software systems. The focus is on the underlying concepts and the issues which arise in the design of parallel rendering algorithms and systems. We examine the different types of parallelism and how they can be applied in rendering applications. Concepts from parallel computing, such as data decomposition, task granularity, scalability, and load balancing, are considered in relation to the rendering problem. We also explore concepts from computer graphics, such as coherence and projection, which have a significant impact on the structure of parallel rendering algorithms. Our survey covers a number of practical considerations as well, including the choice of architectural platform, communication and memory requirements, and the problem of image assembly and display. We illustrate the discussion with numerous examples from the parallel rendering literature, representing most of the principal rendering methods currently used in computer graphics.

  6. A high-quality narrow passband filter for elastic SV waves via aligned parallel separated thin polymethylmethacrylate plates

    Directory of Open Access Journals (Sweden)

    Jun Zhang

    2017-08-01

    Full Text Available We designed a high-quality filter that consists of aligned parallel polymethylmethacrylate (PMMA thin plates with small gaps for elastic SV waves propagate in metals. Both the theoretical model and the full numerical simulation show the transmission spectrum of the elastic SV waves through such a filter has several sharp peaks with flawless transmission within the investigated frequencies. These peaks can be readily tuned by manipulating the geometry parameters of the PMMA plates. Our investigation finds that the same filter performs well for different metals where the elastic SV waves propagated.

  7. The use of coded PCR primers enables high-throughput sequencing of multiple homolog amplification products by 454 parallel sequencing

    DEFF Research Database (Denmark)

    Binladen, Jonas; Gilbert, M Thomas P; Bollback, Jonathan P

    2007-01-01

    BACKGROUND: The invention of the Genome Sequence 20 DNA Sequencing System (454 parallel sequencing platform) has enabled the rapid and high-volume production of sequence data. Until now, however, individual emulsion PCR (emPCR) reactions and subsequent sequencing runs have been unable to combine...... primers that is dependent on the 5' nucleotide of the tag. In particular, primers 5' labelled with a cytosine are heavily overrepresented among the final sequences, while those 5' labelled with a thymine are strongly underrepresented. A weaker bias also exists with regards to the distribution...

  8. Probabilistic Bandwidth Assignment in Wireless Sensor Networks

    OpenAIRE

    Khan , Dawood; Nefzi , Bilel; Santinelli , Luca; Song , Ye-Qiong

    2012-01-01

    International audience; With this paper we offer an insight in designing and analyzing wireless sensor networks in a versatile manner. Our framework applies probabilistic and component-based design principles for the wireless sensor network modeling and consequently analysis; while maintaining flexibility and accuracy. In particular, we address the problem of allocating and reconfiguring the available bandwidth. The framework has been successfully implemented in IEEE 802.15.4 using an Admissi...

  9. Parallel computations

    CERN Document Server

    1982-01-01

    Parallel Computations focuses on parallel computation, with emphasis on algorithms used in a variety of numerical and physical applications and for many different types of parallel computers. Topics covered range from vectorization of fast Fourier transforms (FFTs) and of the incomplete Cholesky conjugate gradient (ICCG) algorithm on the Cray-1 to calculation of table lookups and piecewise functions. Single tridiagonal linear systems and vectorized computation of reactive flow are also discussed.Comprised of 13 chapters, this volume begins by classifying parallel computers and describing techn

  10. Towards Bandwidth Scalable Transceiver Technology for Optical Metro-Access Networks

    DEFF Research Database (Denmark)

    Spolitis, Sandis; Bobrovs, Vjaceslavs; Wagner, Christoph

    2015-01-01

    sliceable transceiver for 1 Gbit/s non-return to zero (NRZ) signal sliced into two slices is presented. Digital signal processing (DSP) power consumption and latency values for proposed sliceable transceiver technique are also discussed. In this research post FEC with 7% overhead error free transmission has......Massive fiber-to-the-home network deployment is creating a challenge for telecommunications network operators: exponential increase of the power consumption at the central offices and a never ending quest for equipment upgrades operating at higher bandwidth. In this paper, we report on flexible...... signal slicing technique, which allows transmission of high-bandwidth signals via low bandwidth electrical and optoelectrical equipment. The presented signal slicing technique is highly scalable in terms of bandwidth which is determined by the number of slices used. In this paper performance of scalable...

  11. High-performance parallel computing in the classroom using the public goods game as an example

    Science.gov (United States)

    Perc, Matjaž

    2017-07-01

    The use of computers in statistical physics is common because the sheer number of equations that describe the behaviour of an entire system particle by particle often makes it impossible to solve them exactly. Monte Carlo methods form a particularly important class of numerical methods for solving problems in statistical physics. Although these methods are simple in principle, their proper use requires a good command of statistical mechanics, as well as considerable computational resources. The aim of this paper is to demonstrate how the usage of widely accessible graphics cards on personal computers can elevate the computing power in Monte Carlo simulations by orders of magnitude, thus allowing live classroom demonstration of phenomena that would otherwise be out of reach. As an example, we use the public goods game on a square lattice where two strategies compete for common resources in a social dilemma situation. We show that the second-order phase transition to an absorbing phase in the system belongs to the directed percolation universality class, and we compare the time needed to arrive at this result by means of the main processor and by means of a suitable graphics card. Parallel computing on graphics processing units has been developed actively during the last decade, to the point where today the learning curve for entry is anything but steep for those familiar with programming. The subject is thus ripe for inclusion in graduate and advanced undergraduate curricula, and we hope that this paper will facilitate this process in the realm of physics education. To that end, we provide a documented source code for an easy reproduction of presented results and for further development of Monte Carlo simulations of similar systems.

  12. A massively parallel sequencing approach uncovers ancient origins and high genetic variability of endangered Przewalski's horses.

    Science.gov (United States)

    Goto, Hiroki; Ryder, Oliver A; Fisher, Allison R; Schultz, Bryant; Kosakovsky Pond, Sergei L; Nekrutenko, Anton; Makova, Kateryna D

    2011-01-01

    The endangered Przewalski's horse is the closest relative of the domestic horse and is the only true wild horse species surviving today. The question of whether Przewalski's horse is the direct progenitor of domestic horse has been hotly debated. Studies of DNA diversity within Przewalski's horses have been sparse but are urgently needed to ensure their successful reintroduction to the wild. In an attempt to resolve the controversy surrounding the phylogenetic position and genetic diversity of Przewalski's horses, we used massively parallel sequencing technology to decipher the complete mitochondrial and partial nuclear genomes for all four surviving maternal lineages of Przewalski's horses. Unlike single-nucleotide polymorphism (SNP) typing usually affected by ascertainment bias, the present method is expected to be largely unbiased. Three mitochondrial haplotypes were discovered-two similar ones, haplotypes I/II, and one substantially divergent from the other two, haplotype III. Haplotypes I/II versus III did not cluster together on a phylogenetic tree, rejecting the monophyly of Przewalski's horse maternal lineages, and were estimated to split 0.117-0.186 Ma, significantly preceding horse domestication. In the phylogeny based on autosomal sequences, Przewalski's horses formed a monophyletic clade, separate from the Thoroughbred domestic horse lineage. Our results suggest that Przewalski's horses have ancient origins and are not the direct progenitors of domestic horses. The analysis of the vast amount of sequence data presented here suggests that Przewalski's and domestic horse lineages diverged at least 0.117 Ma but since then have retained ancestral genetic polymorphism and/or experienced gene flow.

  13. Optimization and parallelization of the thermal–hydraulic subchannel code CTF for high-fidelity multi-physics applications

    International Nuclear Information System (INIS)

    Salko, Robert K.; Schmidt, Rodney C.; Avramova, Maria N.

    2015-01-01

    Highlights: • COBRA-TF was adopted by the Consortium for Advanced Simulation of LWRs. • We have improved code performance to support running large-scale LWR simulations. • Code optimization has led to reductions in execution time and memory usage. • An MPI parallelization has reduced full-core simulation time from days to minutes. - Abstract: This paper describes major improvements to the computational infrastructure of the CTF subchannel code so that full-core, pincell-resolved (i.e., one computational subchannel per real bundle flow channel) simulations can now be performed in much shorter run-times, either in stand-alone mode or as part of coupled-code multi-physics calculations. These improvements support the goals of the Department Of Energy Consortium for Advanced Simulation of Light Water Reactors (CASL) Energy Innovation Hub to develop high fidelity multi-physics simulation tools for nuclear energy design and analysis. A set of serial code optimizations—including fixing computational inefficiencies, optimizing the numerical approach, and making smarter data storage choices—are first described and shown to reduce both execution time and memory usage by about a factor of ten. Next, a “single program multiple data” parallelization strategy targeting distributed memory “multiple instruction multiple data” platforms utilizing domain decomposition is presented. In this approach, data communication between processors is accomplished by inserting standard Message-Passing Interface (MPI) calls at strategic points in the code. The domain decomposition approach implemented assigns one MPI process to each fuel assembly, with each domain being represented by its own CTF input file. The creation of CTF input files, both for serial and parallel runs, is also fully automated through use of a pressurized water reactor (PWR) pre-processor utility that uses a greatly simplified set of user input compared with the traditional CTF input. To run CTF in

  14. Evaluation of RANS and LES models for Natural Convection in High-Aspect-Ratio Parallel Plate Channels

    Science.gov (United States)

    Fradeneck, Austen; Kimber, Mark

    2017-11-01

    The present study evaluates the effectiveness of current RANS and LES models in simulating natural convection in high-aspect ratio parallel plate channels. The geometry under consideration is based on a simplification of the coolant and bypass channels in the very high-temperature gas reactor (VHTR). Two thermal conditions are considered, asymmetric and symmetric wall heating with an applied heat flux to match Rayleigh numbers experienced in the VHTR during a loss of flow accident (LOFA). RANS models are compared to analogous high-fidelity LES simulations. Preliminary results demonstrate the efficacy of the low-Reynolds number k- ɛ formulations and their enhancement to the standard form and Reynolds stress transport model in terms of calculating the turbulence production due to buoyancy and overall mean flow variables.

  15. Efficient Bandwidth Management for Ethernet Passive Optical Networks

    KAUST Repository

    Elrasad, Amr

    2016-01-01

    The increasing bandwidth demands in access networks motivates network operators, networking devices manufacturers, and standardization institutions to search for new approaches for access networks. These approaches should support higher bandwidth

  16. SQDFT: Spectral Quadrature method for large-scale parallel O(N) Kohn-Sham calculations at high temperature

    Science.gov (United States)

    Suryanarayana, Phanish; Pratapa, Phanisri P.; Sharma, Abhiraj; Pask, John E.

    2018-03-01

    We present SQDFT: a large-scale parallel implementation of the Spectral Quadrature (SQ) method for O(N) Kohn-Sham Density Functional Theory (DFT) calculations at high temperature. Specifically, we develop an efficient and scalable finite-difference implementation of the infinite-cell Clenshaw-Curtis SQ approach, in which results for the infinite crystal are obtained by expressing quantities of interest as bilinear forms or sums of bilinear forms, that are then approximated by spatially localized Clenshaw-Curtis quadrature rules. We demonstrate the accuracy of SQDFT by showing systematic convergence of energies and atomic forces with respect to SQ parameters to reference diagonalization results, and convergence with discretization to established planewave results, for both metallic and insulating systems. We further demonstrate that SQDFT achieves excellent strong and weak parallel scaling on computer systems consisting of tens of thousands of processors, with near perfect O(N) scaling with system size and wall times as low as a few seconds per self-consistent field iteration. Finally, we verify the accuracy of SQDFT in large-scale quantum molecular dynamics simulations of aluminum at high temperature.

  17. A novel detection platform for parallel monitoring of DNA hybridization with high sensitivity and specificity

    DEFF Research Database (Denmark)

    Yi, Sun; Perch-Nielsen, Ivan R.; Wang, Zhenyu

    We developed a high-sensitive platform to monior multiple hybridization events in real time. By creating a microoptical array in a polymeric chip, the system combine the excellent discriminative power of supercritical angle fluorescence (SAF) microscopy with high-throughput capabilities of microa......We developed a high-sensitive platform to monior multiple hybridization events in real time. By creating a microoptical array in a polymeric chip, the system combine the excellent discriminative power of supercritical angle fluorescence (SAF) microscopy with high-throughput capabilities...

  18. Design of massively parallel hardware multi-processors for highly-demanding embedded applications

    NARCIS (Netherlands)

    Jozwiak, L.; Jan, Y.

    2013-01-01

    Many new embedded applications require complex computations to be performed to tight schedules, while at the same time demanding low energy consumption and low cost. For implementation of these highly-demanding applications, highly-optimized application-specific multi-processor system-on-a-chip

  19. Churchill: an ultra-fast, deterministic, highly scalable and balanced parallelization strategy for the discovery of human genetic variation in clinical and population-scale genomics.

    Science.gov (United States)

    Kelly, Benjamin J; Fitch, James R; Hu, Yangqiu; Corsmeier, Donald J; Zhong, Huachun; Wetzel, Amy N; Nordquist, Russell D; Newsom, David L; White, Peter

    2015-01-20

    While advances in genome sequencing technology make population-scale genomics a possibility, current approaches for analysis of these data rely upon parallelization strategies that have limited scalability, complex implementation and lack reproducibility. Churchill, a balanced regional parallelization strategy, overcomes these challenges, fully automating the multiple steps required to go from raw sequencing reads to variant discovery. Through implementation of novel deterministic parallelization techniques, Churchill allows computationally efficient analysis of a high-depth whole genome sample in less than two hours. The method is highly scalable, enabling full analysis of the 1000 Genomes raw sequence dataset in a week using cloud resources. http://churchill.nchri.org/.

  20. Fluid limits for Bandwidth-Sharing Networks with Impatience.

    NARCIS (Netherlands)

    Remerova, M.; Reed, J.; Zwart, A.P.

    2014-01-01

    Bandwidth-sharing networks as introduced by Roberts and Massoulié [Roberts JW, Massoulié L (1998) Bandwidth sharing and admission control for elastic traffic. Proc. ITC Specialist Seminar, Yokohama, Japan], Massoulié and Roberts [Massoulié L, Roberts JW (1999) Bandwidth sharing: Objectives and

  1. Low and Expensive Bandwidth Remains Key Bottleneck for ...

    African Journals Online (AJOL)

    These bottlenecks have dwarfed the expectations of the citizens to fully participate in the new world economic order galvanized by e-commerce and world trade. It is estimated that M.I.T in Boston USA has bandwidth allocation that surpasses all the bandwidth allocated to Nigeria put together. Low bandwidth has been found ...

  2. High-efficiency one-dimensional atom localization via two parallel standing-wave fields

    International Nuclear Information System (INIS)

    Wang, Zhiping; Wu, Xuqiang; Lu, Liang; Yu, Benli

    2014-01-01

    We present a new scheme of high-efficiency one-dimensional (1D) atom localization via measurement of upper state population or the probe absorption in a four-level N-type atomic system. By applying two classical standing-wave fields, the localization peak position and number, as well as the conditional position probability, can be easily controlled by the system parameters, and the sub-half-wavelength atom localization is also observed. More importantly, there is 100% detecting probability of the atom in the subwavelength domain when the corresponding conditions are satisfied. The proposed scheme may open up a promising way to achieve high-precision and high-efficiency 1D atom localization. (paper)

  3. Spin-torque diode with tunable sensitivity and bandwidth by out-of-plane magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Li, X.; Zheng, C.; Pong, Philip W. T. [Department of Electrical and Electronic Engineering, The University of Hong Kong (Hong Kong); Zhou, Y., E-mail: yanzhou@hku.hk [School of Electronics Science and Engineering, Nanjing University, Nanjing 210093 (China); Department of Physics, The University of Hong Kong (Hong Kong); Kubota, H.; Yuasa, S. [Spintronics Research Center, National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki 305-8568 (Japan)

    2016-06-06

    Spin-torque diodes based on nanosized magnetic tunnel junctions are novel microwave detectors with high sensitivity and wide frequency bandwidth. While previous reports mainly focus on improving the sensitivity, the approaches to extend the bandwidth are limited. This work experimentally demonstrates that through optimizing the orientation of the external magnetic field, wide bandwidth can be achieved while maintaining high sensitivity. The mechanism of the frequency- and sensitivity-tuning is investigated through analyzing the dependence of resonant frequency and DC voltage on the magnitude and the tilt angle of hard-plane magnetic field. The frequency dependence is qualitatively explicated by Kittel's ferromagnetic resonance model. The asymmetric resonant frequency at positive and negative magnetic field is verified by the numerical simulation considering the in-plane anisotropy. The DC voltage dependence is interpreted through evaluating the misalignment angle between the magnetization of the free layer and the reference layer. The tunability of the detector performance by the magnetic field angle is evaluated through characterizing the sensitivity and bandwidth under 3D magnetic field. The frequency bandwidth up to 9.8 GHz or maximum sensitivity up to 154 mV/mW (after impedance mismatch correction) can be achieved by tuning the angle of the applied magnetic field. The results show that the bandwidth and sensitivity can be controlled and adjusted through optimizing the orientation of the magnetic field for various applications and requirements.

  4. Parallel algorithms

    CERN Document Server

    Casanova, Henri; Robert, Yves

    2008-01-01

    ""…The authors of the present book, who have extensive credentials in both research and instruction in the area of parallelism, present a sound, principled treatment of parallel algorithms. … This book is very well written and extremely well designed from an instructional point of view. … The authors have created an instructive and fascinating text. The book will serve researchers as well as instructors who need a solid, readable text for a course on parallelism in computing. Indeed, for anyone who wants an understandable text from which to acquire a current, rigorous, and broad vi

  5. SOLVING BY PARALLEL COMPUTATION THE POISSON PROBLEM FOR HIGH INTENSITY BEAMS IN CIRCULAR ACCELERATORS

    International Nuclear Information System (INIS)

    LUCCIO, A.U.; DIMPERIO, N.L.; SAMULYAK, R.; BEEB-WANG, J.

    2001-01-01

    Simulation of high intensity accelerators leads to the solution of the Poisson Equation, to calculate space charge forces in the presence of acceleration chamber walls. We reduced the problem to ''two-and-a-half'' dimensions for long particle bunches, characteristic of large circular accelerators, and applied the results to the tracking code Orbit

  6. High-throughput liquid-liquid extraction in 96-well format: Parallel artificial liquid membrane extraction

    DEFF Research Database (Denmark)

    Gjelstad, Astrid; Andresen, Alf Terje; Dahlgren, Anders

    2017-01-01

    , highly efficient sample cleanup, and direct compatibility with liquid chromatography–mass spectrometry (LC–MS). The consumption of hazardous organic solvents is also almost eliminated using PALME as the sample preparation technique. This article summarizes current experiences with PALME, based on work...

  7. Parallel Störmer-Cowell methods for high-precision orbit computations

    NARCIS (Netherlands)

    P.J. van der Houwen; E. Messina; J.J.B. de Swart (Jacques)

    1998-01-01

    textabstractMany orbit problems in celestial mechanics are described by (nonstiff) initial-value problems (IVPs) for second-order ordinary differential equations of the form $y' = {bf f (y)$. The most successful integration methods are based on high-order Runge-Kutta-Nyström formulas. However, these

  8. High sensitivity and high Q-factor nanoslotted parallel quadrabeam photonic crystal cavity for real-time and label-free sensing

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Daquan [Rowland Institute at Harvard University, Cambridge, Massachusetts 02142 (United States); State Key Laboratory of Information Photonics and Optical Communications, School of Information and Communication Engineering, Beijing University of Posts and Telecommunications, Beijing 100876 (China); School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138 (United States); Kita, Shota; Wang, Cheng; Lončar, Marko [School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138 (United States); Liang, Feng; Quan, Qimin [Rowland Institute at Harvard University, Cambridge, Massachusetts 02142 (United States); Tian, Huiping; Ji, Yuefeng [State Key Laboratory of Information Photonics and Optical Communications, School of Information and Communication Engineering, Beijing University of Posts and Telecommunications, Beijing 100876 (China)

    2014-08-11

    We experimentally demonstrate a label-free sensor based on nanoslotted parallel quadrabeam photonic crystal cavity (NPQC). The NPQC possesses both high sensitivity and high Q-factor. We achieved sensitivity (S) of 451 nm/refractive index unit and Q-factor >7000 in water at telecom wavelength range, featuring a sensor figure of merit >2000, an order of magnitude improvement over the previous photonic crystal sensors. In addition, we measured the streptavidin-biotin binding affinity and detected 10 ag/mL concentrated streptavidin in the phosphate buffered saline solution.

  9. High-Bandwidth Tactical-Network Data Analysis in a High-Performance-Computing (HPC) Environment: Transport Protocol (Transmission Control Protocol/User Datagram Protocol [TCP/UDP]) Analysis

    Science.gov (United States)

    2015-09-01

    the network Mac8 Medium Access Control ( Mac ) (Ethernet) address observed as destination for outgoing packets subsessionid8 Zero-based index of...15. SUBJECT TERMS tactical networks, data reduction, high-performance computing, data analysis, big data 16. SECURITY CLASSIFICATION OF: 17...Integer index of row cts_deid Device (instrument) Identifier where observation took place cts_collpt Collection point or logical observation point on

  10. High Performance Molecular Visualization: In-Situ and Parallel Rendering with EGL

    Science.gov (United States)

    Stone, John E.; Messmer, Peter; Sisneros, Robert; Schulten, Klaus

    2016-01-01

    Large scale molecular dynamics simulations produce terabytes of data that is impractical to transfer to remote facilities. It is therefore necessary to perform visualization tasks in-situ as the data are generated, or by running interactive remote visualization sessions and batch analyses co-located with direct access to high performance storage systems. A significant challenge for deploying visualization software within clouds, clusters, and supercomputers involves the operating system software required to initialize and manage graphics acceleration hardware. Recently, it has become possible for applications to use the Embedded-system Graphics Library (EGL) to eliminate the requirement for windowing system software on compute nodes, thereby eliminating a significant obstacle to broader use of high performance visualization applications. We outline the potential benefits of this approach in the context of visualization applications used in the cloud, on commodity clusters, and supercomputers. We discuss the implementation of EGL support in VMD, a widely used molecular visualization application, and we outline benefits of the approach for molecular visualization tasks on petascale computers, clouds, and remote visualization servers. We then provide a brief evaluation of the use of EGL in VMD, with tests using developmental graphics drivers on conventional workstations and on Amazon EC2 G2 GPU-accelerated cloud instance types. We expect that the techniques described here will be of broad benefit to many other visualization applications. PMID:27747137

  11. A CFD Heterogeneous Parallel Solver Based on Collaborating CPU and GPU

    Science.gov (United States)

    Lai, Jianqi; Tian, Zhengyu; Li, Hua; Pan, Sha

    2018-03-01

    Since Graphic Processing Unit (GPU) has a strong ability of floating-point computation and memory bandwidth for data parallelism, it has been widely used in the areas of common computing such as molecular dynamics (MD), computational fluid dynamics (CFD) and so on. The emergence of compute unified device architecture (CUDA), which reduces the complexity of compiling program, brings the great opportunities to CFD. There are three different modes for parallel solution of NS equations: parallel solver based on CPU, parallel solver based on GPU and heterogeneous parallel solver based on collaborating CPU and GPU. As we can see, GPUs are relatively rich in compute capacity but poor in memory capacity and the CPUs do the opposite. We need to make full use of the GPUs and CPUs, so a CFD heterogeneous parallel solver based on collaborating CPU and GPU has been established. Three cases are presented to analyse the solver’s computational accuracy and heterogeneous parallel efficiency. The numerical results agree well with experiment results, which demonstrate that the heterogeneous parallel solver has high computational precision. The speedup on a single GPU is more than 40 for laminar flow, it decreases for turbulent flow, but it still can reach more than 20. What’s more, the speedup increases as the grid size becomes larger.

  12. Massively parallel mathematical sieves

    Energy Technology Data Exchange (ETDEWEB)

    Montry, G.R.

    1989-01-01

    The Sieve of Eratosthenes is a well-known algorithm for finding all prime numbers in a given subset of integers. A parallel version of the Sieve is described that produces computational speedups over 800 on a hypercube with 1,024 processing elements for problems of fixed size. Computational speedups as high as 980 are achieved when the problem size per processor is fixed. The method of parallelization generalizes to other sieves and will be efficient on any ensemble architecture. We investigate two highly parallel sieves using scattered decomposition and compare their performance on a hypercube multiprocessor. A comparison of different parallelization techniques for the sieve illustrates the trade-offs necessary in the design and implementation of massively parallel algorithms for large ensemble computers.

  13. Design of bandwidth tunable HTS filter using H-shaped waveguides

    Energy Technology Data Exchange (ETDEWEB)

    Koike, Y. [Department of Electrical Engineering, University of Yamanashi, Nakagawa-Sekiya Laboratory, 4-3-11 Takeda, Kofu 400-8511 (Japan); Sekiya, N., E-mail: nsekiya@yamanashi.ac.j [Department of Electrical Engineering, University of Yamanashi, Nakagawa-Sekiya Laboratory, 4-3-11 Takeda, Kofu 400-8511 (Japan); Nakagawa, Y. [Department of Electrical Engineering, University of Yamanashi, Nakagawa-Sekiya Laboratory, 4-3-11 Takeda, Kofu 400-8511 (Japan); Ohshima, S. [Yamagata University, 4-3-16 Johnan, Yonezawa 992-8510 (Japan)

    2009-10-15

    We have developed a bandwidth tuning method for use in high-temperature superconducting (HTS) microstrip filters. Several H-shaped waveguides are placed between the resonators, and the bandwidth is adjusted by changing the switch states of the waveguides. The coupling coefficients between the resonators are controlled by switching the connection or isolation of the center gaps of the waveguides so as to tune the bandwidth. The effects of using this method were evaluated by simulation using a filter composed of 3-pole half-wavelength straight-line resonators with an H-shaped waveguide between each pair and additional electric pads for post-tuning trimming. The filter was designed to have a center frequency of 5 GHz and a bandwidth of 100 MHz by using an electromagnetic simulator based on the moment method. The simulation showed that bandwidth tuning of 150 MHz can be obtained by using H-shaped waveguides to adjust the coupling coefficients. It also showed that using additional electric pads around the feed lines, which was previously shown to be useful for trimming to improve insertion loss after center-frequency tuning, is also useful for bandwidth tuning.

  14. Multi-granularity Bandwidth Allocation for Large-Scale WDM/TDM PON

    Science.gov (United States)

    Gao, Ziyue; Gan, Chaoqin; Ni, Cuiping; Shi, Qiongling

    2017-12-01

    WDM (wavelength-division multiplexing)/TDM (time-division multiplexing) PON (passive optical network) is being viewed as a promising solution for delivering multiple services and applications, such as high-definition video, video conference and data traffic. Considering the real-time transmission, QoS (quality of services) requirements and differentiated services model, a multi-granularity dynamic bandwidth allocation (DBA) in both domains of wavelengths and time for large-scale hybrid WDM/TDM PON is proposed in this paper. The proposed scheme achieves load balance by using the bandwidth prediction. Based on the bandwidth prediction, the wavelength assignment can be realized fairly and effectively to satisfy the different demands of various classes. Specially, the allocation of residual bandwidth further augments the DBA and makes full use of bandwidth resources in the network. To further improve the network performance, two schemes named extending the cycle of one free wavelength (ECoFW) and large bandwidth shrinkage (LBS) are proposed, which can prevent transmission from interruption when the user employs more than one wavelength. The simulation results show the effectiveness of the proposed scheme.

  15. Wide-bandwidth bilateral control using two-stage actuator system

    International Nuclear Information System (INIS)

    Kokuryu, Saori; Izutsu, Masaki; Kamamichi, Norihiro; Ishikawa, Jun

    2015-01-01

    This paper proposes a two-stage actuator system that consists of a coarse actuator driven by a ball screw with an AC motor (the first stage) and a fine actuator driven by a voice coil motor (the second stage). The proposed two-stage actuator system is applied to make a wide-bandwidth bilateral control system without needing expensive high-performance actuators. In the proposed system, the first stage has a wide moving range with a narrow control bandwidth, and the second stage has a narrow moving range with a wide control bandwidth. By consolidating these two inexpensive actuators with different control bandwidths in a complementary manner, a wide bandwidth bilateral control system can be constructed based on a mechanical impedance control. To show the validity of the proposed method, a prototype of the two-stage actuator system has been developed and basic performance was evaluated by experiment. The experimental results showed that a light mechanical impedance with a mass of 10 g and a damping coefficient of 2.5 N/(m/s) that is an important factor to establish good transparency in bilateral control has been successfully achieved and also showed that a better force and position responses between a master and slave is achieved by using the proposed two-stage actuator system compared with a narrow bandwidth case using a single ball screw system. (author)

  16. A real-time hybrid neuron network for highly parallel cognitive systems.

    Science.gov (United States)

    Christiaanse, Gerrit Jan; Zjajo, Amir; Galuzzi, Carlo; van Leuken, Rene

    2016-08-01

    For comprehensive understanding of how neurons communicate with each other, new tools need to be developed that can accurately mimic the behaviour of such neurons and neuron networks under `real-time' constraints. In this paper, we propose an easily customisable, highly pipelined, neuron network design, which executes optimally scheduled floating-point operations for maximal amount of biophysically plausible neurons per FPGA family type. To reduce the required amount of resources without adverse effect on the calculation latency, a single exponent instance is used for multiple neuron calculation operations. Experimental results indicate that the proposed network design allows the simulation of up to 1188 neurons on Virtex7 (XC7VX550T) device in brain real-time yielding a speed-up of x12.4 compared to the state-of-the art.

  17. Massively parallel digital high resolution melt for rapid and absolutely quantitative sequence profiling

    Science.gov (United States)

    Velez, Daniel Ortiz; Mack, Hannah; Jupe, Julietta; Hawker, Sinead; Kulkarni, Ninad; Hedayatnia, Behnam; Zhang, Yang; Lawrence, Shelley; Fraley, Stephanie I.

    2017-02-01

    In clinical diagnostics and pathogen detection, profiling of complex samples for low-level genotypes represents a significant challenge. Advances in speed, sensitivity, and extent of multiplexing of molecular pathogen detection assays are needed to improve patient care. We report the development of an integrated platform enabling the identification of bacterial pathogen DNA sequences in complex samples in less than four hours. The system incorporates a microfluidic chip and instrumentation to accomplish universal PCR amplification, High Resolution Melting (HRM), and machine learning within 20,000 picoliter scale reactions, simultaneously. Clinically relevant concentrations of bacterial DNA molecules are separated by digitization across 20,000 reactions and amplified with universal primers targeting the bacterial 16S gene. Amplification is followed by HRM sequence fingerprinting in all reactions, simultaneously. The resulting bacteria-specific melt curves are identified by Support Vector Machine learning, and individual pathogen loads are quantified. The platform reduces reaction volumes by 99.995% and achieves a greater than 200-fold increase in dynamic range of detection compared to traditional PCR HRM approaches. Type I and II error rates are reduced by 99% and 100% respectively, compared to intercalating dye-based digital PCR (dPCR) methods. This technology could impact a number of quantitative profiling applications, especially infectious disease diagnostics.

  18. Choosing processor array configuration by performance modeling for a highly parallel linear algebra algorithm

    International Nuclear Information System (INIS)

    Littlefield, R.J.; Maschhoff, K.J.

    1991-04-01

    Many linear algebra algorithms utilize an array of processors across which matrices are distributed. Given a particular matrix size and a maximum number of processors, what configuration of processors, i.e., what size and shape array, will execute the fastest? The answer to this question depends on tradeoffs between load balancing, communication startup and transfer costs, and computational overhead. In this paper we analyze in detail one algorithm: the blocked factored Jacobi method for solving dense eigensystems. A performance model is developed to predict execution time as a function of the processor array and matrix sizes, plus the basic computation and communication speeds of the underlying computer system. In experiments on a large hypercube (up to 512 processors), this model has been found to be highly accurate (mean error ∼ 2%) over a wide range of matrix sizes (10 x 10 through 200 x 200) and processor counts (1 to 512). The model reveals, and direct experiment confirms, that the tradeoffs mentioned above can be surprisingly complex and counterintuitive. We propose decision procedures based directly on the performance model to choose configurations for fastest execution. The model-based decision procedures are compared to a heuristic strategy and shown to be significantly better. 7 refs., 8 figs., 1 tab

  19. The One-node CMFD Computational Framework for Highly Parallel Reactor Analysis

    International Nuclear Information System (INIS)

    Kim, Yong Hee

    2016-01-01

    This paper presents one such possible approach named the One-Node and Two-Node Hybrid CMFD method; One-Node CMFD is used to solve the global problem, while Two-Node NEM (Nodal Expansion Method) CMFD replaces FMFD as the local problem. Rapid advancement in computing capabilities has enabled the pursuit for high-fidelity tools in analyzing the reactor configurations. One such tool that gains a lot of recent attention is the pin-by-pin core calculation via local-global iteration with nonlinear acceleration scheme. One-Node CMFD method uses two correction terms to preserve the interface current and flux, in contrast to one correction term employed by conventional nonlinear iterative method proposed. With two correction terms, One-Node CMFD can reduce computing time of local FMFD (Fine-Mesh Finite Difference) as it nonlinearly couples the CMFD and FMFD methods in global-local iterations. Nonetheless, retrieving the pinlevel information from the local FMFD is very time consuming. As such, a more flexible approach is needed to address this challenge.

  20. WATERLOPP V2/64: A highly parallel machine for numerical computation

    Science.gov (United States)

    Ostlund, Neil S.

    1985-07-01

    Current technological trends suggest that the high performance scientific machines of the future are very likely to consist of a large number (greater than 1024) of processors connected and communicating with each other in some as yet undetermined manner. Such an assembly of processors should behave as a single machine in obtaining numerical solutions to scientific problems. However, the appropriate way of organizing both the hardware and software of such an assembly of processors is an unsolved and active area of research. It is particularly important to minimize the organizational overhead of interprocessor comunication, global synchronization, and contention for shared resources if the performance of a large number ( n) of processors is to be anything like the desirable n times the performance of a single processor. In many situations, adding a processor actually decreases the performance of the overall system since the extra organizational overhead is larger than the extra processing power added. The systolic loop architecture is a new multiple processor architecture which attemps at a solution to the problem of how to organize a large number of asynchronous processors into an effective computational system while minimizing the organizational overhead. This paper gives a brief overview of the basic systolic loop architecture, systolic loop algorithms for numerical computation, and a 64-processor implementation of the architecture, WATERLOOP V2/64, that is being used as a testbed for exploring the hardware, software, and algorithmic aspects of the architecture.

  1. A Parallel Butterfly Algorithm

    KAUST Repository

    Poulson, Jack; Demanet, Laurent; Maxwell, Nicholas; Ying, Lexing

    2014-01-01

    The butterfly algorithm is a fast algorithm which approximately evaluates a discrete analogue of the integral transform (Equation Presented.) at large numbers of target points when the kernel, K(x, y), is approximately low-rank when restricted to subdomains satisfying a certain simple geometric condition. In d dimensions with O(Nd) quasi-uniformly distributed source and target points, when each appropriate submatrix of K is approximately rank-r, the running time of the algorithm is at most O(r2Nd logN). A parallelization of the butterfly algorithm is introduced which, assuming a message latency of α and per-process inverse bandwidth of β, executes in at most (Equation Presented.) time using p processes. This parallel algorithm was then instantiated in the form of the open-source DistButterfly library for the special case where K(x, y) = exp(iΦ(x, y)), where Φ(x, y) is a black-box, sufficiently smooth, real-valued phase function. Experiments on Blue Gene/Q demonstrate impressive strong-scaling results for important classes of phase functions. Using quasi-uniform sources, hyperbolic Radon transforms, and an analogue of a three-dimensional generalized Radon transform were, respectively, observed to strong-scale from 1-node/16-cores up to 1024-nodes/16,384-cores with greater than 90% and 82% efficiency, respectively. © 2014 Society for Industrial and Applied Mathematics.

  2. A Parallel Butterfly Algorithm

    KAUST Repository

    Poulson, Jack

    2014-02-04

    The butterfly algorithm is a fast algorithm which approximately evaluates a discrete analogue of the integral transform (Equation Presented.) at large numbers of target points when the kernel, K(x, y), is approximately low-rank when restricted to subdomains satisfying a certain simple geometric condition. In d dimensions with O(Nd) quasi-uniformly distributed source and target points, when each appropriate submatrix of K is approximately rank-r, the running time of the algorithm is at most O(r2Nd logN). A parallelization of the butterfly algorithm is introduced which, assuming a message latency of α and per-process inverse bandwidth of β, executes in at most (Equation Presented.) time using p processes. This parallel algorithm was then instantiated in the form of the open-source DistButterfly library for the special case where K(x, y) = exp(iΦ(x, y)), where Φ(x, y) is a black-box, sufficiently smooth, real-valued phase function. Experiments on Blue Gene/Q demonstrate impressive strong-scaling results for important classes of phase functions. Using quasi-uniform sources, hyperbolic Radon transforms, and an analogue of a three-dimensional generalized Radon transform were, respectively, observed to strong-scale from 1-node/16-cores up to 1024-nodes/16,384-cores with greater than 90% and 82% efficiency, respectively. © 2014 Society for Industrial and Applied Mathematics.

  3. Bandwidth Extension of Telephone Speech Aided by Data Embedding

    Directory of Open Access Journals (Sweden)

    Sagi Ariel

    2007-01-01

    Full Text Available A system for bandwidth extension of telephone speech, aided by data embedding, is presented. The proposed system uses the transmitted analog narrowband speech signal as a carrier of the side information needed to carry out the bandwidth extension. The upper band of the wideband speech is reconstructed at the receiving end from two components: a synthetic wideband excitation signal, generated from the narrowband telephone speech and a wideband spectral envelope, parametrically represented and transmitted as embedded data in the telephone speech. We propose a novel data embedding scheme, in which the scalar Costa scheme is combined with an auditory masking model allowing high rate transparent embedding, while maintaining a low bit error rate. The signal is transformed to the frequency domain via the discrete Hartley transform (DHT and is partitioned into subbands. Data is embedded in an adaptively chosen subset of subbands by modifying the DHT coefficients. In our simulations, high quality wideband speech was obtained from speech transmitted over a telephone line (characterized by spectral magnitude distortion, dispersion, and noise, in which side information data is transparently embedded at the rate of 600 information bits/second and with a bit error rate of approximately . In a listening test, the reconstructed wideband speech was preferred (at different degrees over conventional telephone speech in of the test utterances.

  4. Bandwidth Extension of Telephone Speech Aided by Data Embedding

    Directory of Open Access Journals (Sweden)

    David Malah

    2007-01-01

    Full Text Available A system for bandwidth extension of telephone speech, aided by data embedding, is presented. The proposed system uses the transmitted analog narrowband speech signal as a carrier of the side information needed to carry out the bandwidth extension. The upper band of the wideband speech is reconstructed at the receiving end from two components: a synthetic wideband excitation signal, generated from the narrowband telephone speech and a wideband spectral envelope, parametrically represented and transmitted as embedded data in the telephone speech. We propose a novel data embedding scheme, in which the scalar Costa scheme is combined with an auditory masking model allowing high rate transparent embedding, while maintaining a low bit error rate. The signal is transformed to the frequency domain via the discrete Hartley transform (DHT and is partitioned into subbands. Data is embedded in an adaptively chosen subset of subbands by modifying the DHT coefficients. In our simulations, high quality wideband speech was obtained from speech transmitted over a telephone line (characterized by spectral magnitude distortion, dispersion, and noise, in which side information data is transparently embedded at the rate of 600 information bits/second and with a bit error rate of approximately 3⋅10−4. In a listening test, the reconstructed wideband speech was preferred (at different degrees over conventional telephone speech in 92.5% of the test utterances.

  5. High-voltage isolation transformer for sub-nanosecond rise time pulses constructed with annular parallel-strip transmission lines.

    Science.gov (United States)

    Homma, Akira

    2011-07-01

    A novel annular parallel-strip transmission line was devised to construct high-voltage high-speed pulse isolation transformers. The transmission lines can easily realize stable high-voltage operation and good impedance matching between primary and secondary circuits. The time constant for the step response of the transformer was calculated by introducing a simple low-frequency equivalent circuit model. Results show that the relation between the time constant and low-cut-off frequency of the transformer conforms to the theory of the general first-order linear time-invariant system. Results also show that the test transformer composed of the new transmission lines can transmit about 600 ps rise time pulses across the dc potential difference of more than 150 kV with insertion loss of -2.5 dB. The measured effective time constant of 12 ns agreed exactly with the theoretically predicted value. For practical applications involving the delivery of synchronized trigger signals to a dc high-voltage electron gun station, the transformer described in this paper exhibited advantages over methods using fiber optic cables for the signal transfer system. This transformer has no jitter or breakdown problems that invariably occur in active circuit components.

  6. Parallel Algorithm for GPU Processing; for use in High Speed Machine Vision Sensing of Cotton Lint Trash

    Directory of Open Access Journals (Sweden)

    Mathew G. Pelletier

    2008-02-01

    Full Text Available One of the main hurdles standing in the way of optimal cleaning of cotton lint isthe lack of sensing systems that can react fast enough to provide the control system withreal-time information as to the level of trash contamination of the cotton lint. This researchexamines the use of programmable graphic processing units (GPU as an alternative to thePC’s traditional use of the central processing unit (CPU. The use of the GPU, as analternative computation platform, allowed for the machine vision system to gain asignificant improvement in processing time. By improving the processing time, thisresearch seeks to address the lack of availability of rapid trash sensing systems and thusalleviate a situation in which the current systems view the cotton lint either well before, orafter, the cotton is cleaned. This extended lag/lead time that is currently imposed on thecotton trash cleaning control systems, is what is responsible for system operators utilizing avery large dead-band safety buffer in order to ensure that the cotton lint is not undercleaned.Unfortunately, the utilization of a large dead-band buffer results in the majority ofthe cotton lint being over-cleaned which in turn causes lint fiber-damage as well assignificant losses of the valuable lint due to the excessive use of cleaning machinery. Thisresearch estimates that upwards of a 30% reduction in lint loss could be gained through theuse of a tightly coupled trash sensor to the cleaning machinery control systems. Thisresearch seeks to improve processing times through the development of a new algorithm forcotton trash sensing that allows for implementation on a highly parallel architecture.Additionally, by moving the new parallel algorithm onto an alternative computing platform,the graphic processing unit “GPU”, for processing of the cotton trash images, a speed up ofover 6.5 times, over optimized code running on the PC’s central processing

  7. Resistor Combinations for Parallel Circuits.

    Science.gov (United States)

    McTernan, James P.

    1978-01-01

    To help simplify both teaching and learning of parallel circuits, a high school electricity/electronics teacher presents and illustrates the use of tables of values for parallel resistive circuits in which total resistances are whole numbers. (MF)

  8. X-ray computed tomography comparison of individual and parallel assembled commercial lithium iron phosphate batteries at end of life after high rate cycling

    Science.gov (United States)

    Carter, Rachel; Huhman, Brett; Love, Corey T.; Zenyuk, Iryna V.

    2018-03-01

    X-ray computed tomography (X-ray CT) across multiple length scales is utilized for the first time to investigate the physical abuse of high C-rate pulsed discharge on cells wired individually and in parallel.. Manufactured lithium iron phosphate cells boasting high rate capability were pulse power tested in both wiring conditions with high discharge currents of 10C for a high number of cycles (up to 1200) until end of life (health (SOH) monitoring methods, is diagnosed using CT by rendering the interior current collector without harm or alteration to the active materials. Correlation of CT observations to the electrochemical pulse data from the parallel-wired cells reveals the risk of parallel wiring during high C-rate pulse discharge.

  9. Signal enhancement due to high-Z nanofilm electrodes in parallel plate ionization chambers with variable microgaps.

    Science.gov (United States)

    Brivio, Davide; Sajo, Erno; Zygmanski, Piotr

    2017-12-01

    We developed a method for measuring signal enhancement produced by high-Z nanofilm electrodes in parallel plate ionization chambers with variable thickness microgaps. We used a laboratory-made variable gap parallel plate ionization chamber with nanofilm electrodes made of aluminum-aluminum (Al-Al) and aluminum-tantalum (Al-Ta). The electrodes were evaporated on 1 mm thick glass substrates. The interelectrode air gap was varied from 3 μm to 1 cm. The gap size was measured using a digital micrometer and it was confirmed by capacitance measurements. The electric field in the chamber was kept between 0.1 kV/cm and 1 kV/cm for all the gap sizes by applying appropriate compensating voltages. The chamber was exposed to 120 kVp X-rays. The current was measured using a commercial data acquisition system with temporal resolution of 600 Hz. In addition, radiation transport simulations were carried out to characterize the dose, D(x), high-energy electron current, J(x), and deposited charge, Q(x), as a function of distance, x, from the electrodes. A deterministic method was selected over Monte Carlo due to its ability to produce results with 10 nm spatial resolution without stochastic uncertainties. Experimental signal enhancement ratio, SER(G) which we defined as the ratio of signal for Al-air-Ta to signal for Al-air-Al for each gap size, was compared to computations. The individual contributions of dose, electron current, and charge deposition to the signal enhancement were determined. Experimental signals matched computed data for all gap sizes after accounting for several contributions to the signal: (a) charge carrier generated via ionization due to the energy deposited in the air gap, D(x); (b) high-energy electron current, J(x), leaking from high-Z electrode (Ta) toward low-Z electrode (Al); (c) deposited charge in the air gap, Q(x); and (d) the decreased collection efficiency for large gaps (>~500 μm). Q(x) accounts for the electrons below 100 eV, which are

  10. Structural Directed Growth of Ultrathin Parallel Birnessite on β-MnO2 for High-Performance Asymmetric Supercapacitors.

    Science.gov (United States)

    Zhu, Shijin; Li, Li; Liu, Jiabin; Wang, Hongtao; Wang, Tian; Zhang, Yuxin; Zhang, Lili; Ruoff, Rodney S; Dong, Fan

    2018-02-27

    Two-dimensional birnessite has attracted attention for electrochemical energy storage because of the presence of redox active Mn 4+ /Mn 3+ ions and spacious interlayer channels available for ions diffusion. However, current strategies are largely limited to enhancing the electrical conductivity of birnessite. One key limitation affecting the electrochemical properties of birnessite is the poor utilization of the MnO 6 unit. Here, we assemble β-MnO 2 /birnessite core-shell structure that exploits the exposed crystal face of β-MnO 2 as the core and ultrathin birnessite sheets that have the structure advantage to enhance the utilization efficiency of the Mn from the bulk. Our birnessite that has sheets parallel to each other is found to have unusual crystal structure with interlayer spacing, Mn(III)/Mn(IV) ratio and the content of the balancing cations differing from that of the common birnessite. The substrate directed growth mechanism is carefully investigated. The as-prepared core-shell nanostructures enhance the exposed surface area of birnessite and achieve high electrochemical performances (for example, 657 F g -1 in 1 M Na 2 SO 4 electrolyte based on the weight of parallel birnessite) and excellent rate capability over a potential window of up to 1.2 V. This strategy opens avenues for fundamental studies of birnessite and its properties and suggests the possibility of its use in energy storage and other applications. The potential window of an asymmetric supercapacitor that was assembled with this material can be enlarged to 2.2 V (in aqueous electrolyte) with a good cycling ability.

  11. Optimal Bandwidth Selection for Kernel Density Functionals Estimation

    Directory of Open Access Journals (Sweden)

    Su Chen

    2015-01-01

    Full Text Available The choice of bandwidth is crucial to the kernel density estimation (KDE and kernel based regression. Various bandwidth selection methods for KDE and local least square regression have been developed in the past decade. It has been known that scale and location parameters are proportional to density functionals ∫γ(xf2(xdx with appropriate choice of γ(x and furthermore equality of scale and location tests can be transformed to comparisons of the density functionals among populations. ∫γ(xf2(xdx can be estimated nonparametrically via kernel density functionals estimation (KDFE. However, the optimal bandwidth selection for KDFE of ∫γ(xf2(xdx has not been examined. We propose a method to select the optimal bandwidth for the KDFE. The idea underlying this method is to search for the optimal bandwidth by minimizing the mean square error (MSE of the KDFE. Two main practical bandwidth selection techniques for the KDFE of ∫γ(xf2(xdx are provided: Normal scale bandwidth selection (namely, “Rule of Thumb” and direct plug-in bandwidth selection. Simulation studies display that our proposed bandwidth selection methods are superior to existing density estimation bandwidth selection methods in estimating density functionals.

  12. Totally parallel multilevel algorithms

    Science.gov (United States)

    Frederickson, Paul O.

    1988-01-01

    Four totally parallel algorithms for the solution of a sparse linear system have common characteristics which become quite apparent when they are implemented on a highly parallel hypercube such as the CM2. These four algorithms are Parallel Superconvergent Multigrid (PSMG) of Frederickson and McBryan, Robust Multigrid (RMG) of Hackbusch, the FFT based Spectral Algorithm, and Parallel Cyclic Reduction. In fact, all four can be formulated as particular cases of the same totally parallel multilevel algorithm, which are referred to as TPMA. In certain cases the spectral radius of TPMA is zero, and it is recognized to be a direct algorithm. In many other cases the spectral radius, although not zero, is small enough that a single iteration per timestep keeps the local error within the required tolerance.

  13. Parallel computing works

    Energy Technology Data Exchange (ETDEWEB)

    1991-10-23

    An account of the Caltech Concurrent Computation Program (C{sup 3}P), a five year project that focused on answering the question: Can parallel computers be used to do large-scale scientific computations '' As the title indicates, the question is answered in the affirmative, by implementing numerous scientific applications on real parallel computers and doing computations that produced new scientific results. In the process of doing so, C{sup 3}P helped design and build several new computers, designed and implemented basic system software, developed algorithms for frequently used mathematical computations on massively parallel machines, devised performance models and measured the performance of many computers, and created a high performance computing facility based exclusively on parallel computers. While the initial focus of C{sup 3}P was the hypercube architecture developed by C. Seitz, many of the methods developed and lessons learned have been applied successfully on other massively parallel architectures.

  14. A modified parallel artificial membrane permeability assay for evaluating the bioconcentration of highly hydrophobic chemicals in fish.

    Science.gov (United States)

    Kwon, Jung-Hwan; Escher, Beate I

    2008-03-01

    Low cost in vitro tools are needed at the screening stage of assessment of bioaccumulation potential of new and existing chemicals because the number of chemical substances that needs to be tested highly exceeds the capacity of in vivo bioconcentration tests. Thus, the parallel artificial membrane permeability assay (PAMPA) system was modified to predict passive uptake/ elimination rate in fish. To overcome the difficulties associated with low aqueous solubility and high membrane affinity of highly hydrophobic chemicals, we measured the rate of permeation from the donor poly(dimethylsiloxane)(PDMS) disk to the acceptor PDMS disk through aqueous and PDMS membrane boundary layers and term the modified PAMPA system "PDMS-PAMPA". Twenty chemicals were selected for validation of PDMS-PAMPA. The measured permeability is proportional to the passive elimination rate constant in fish and was used to predict the "minimum" in vivo elimination rate constant. The in vivo data were very close to predicted values except for a few polar chemicals and metabolically active chemicals, such as pyrene and benzo[a]pyrene. Thus, PDMS-PAMPA can be an appropriate in vitro system for nonmetabolizable chemicals. Combination with metabolic clearance rates using a battery of metabolic degradation assays would enhance the applicability for metabolizable chemicals.

  15. Bandwidth Analysis of Smart Meter Network Infrastructure

    DEFF Research Database (Denmark)

    Balachandran, Kardi; Olsen, Rasmus Løvenstein; Pedersen, Jens Myrup

    2014-01-01

    Advanced Metering Infrastructure (AMI) is a net-work infrastructure in Smart Grid, which links the electricity customers to the utility company. This network enables smart services by making it possible for the utility company to get an overview of their customers power consumption and also control...... devices in their costumers household e.g. heat pumps. With these smart services, utility companies can do load balancing on the grid by shifting load using resources the customers have. The problem investigated in this paper is what bandwidth require-ments can be expected when implementing such network...... to utilize smart meters and which existing broadband network technologies can facilitate this smart meter service. Initially, scenarios for smart meter infrastructure are identified. The paper defines abstraction models which cover the AMI scenarios. When the scenario has been identified a general overview...

  16. Optimal filter bandwidth for pulse oximetry

    Science.gov (United States)

    Stuban, Norbert; Niwayama, Masatsugu

    2012-10-01

    Pulse oximeters contain one or more signal filtering stages between the photodiode and microcontroller. These filters are responsible for removing the noise while retaining the useful frequency components of the signal, thus improving the signal-to-noise ratio. The corner frequencies of these filters affect not only the noise level, but also the shape of the pulse signal. Narrow filter bandwidth effectively suppresses the noise; however, at the same time, it distorts the useful signal components by decreasing the harmonic content. In this paper, we investigated the influence of the filter bandwidth on the accuracy of pulse oximeters. We used a pulse oximeter tester device to produce stable, repetitive pulse waves with digitally adjustable R ratio and heart rate. We built a pulse oximeter and attached it to the tester device. The pulse oximeter digitized the current of its photodiode directly, without any analog signal conditioning. We varied the corner frequency of the low-pass filter in the pulse oximeter in the range of 0.66-15 Hz by software. For the tester device, the R ratio was set to R = 1.00, and the R ratio deviation measured by the pulse oximeter was monitored as a function of the corner frequency of the low-pass filter. The results revealed that lowering the corner frequency of the low-pass filter did not decrease the accuracy of the oxygen level measurements. The lowest possible value of the corner frequency of the low-pass filter is the fundamental frequency of the pulse signal. We concluded that the harmonics of the pulse signal do not contribute to the accuracy of pulse oximetry. The results achieved by the pulse oximeter tester were verified by human experiments, performed on five healthy subjects. The results of the human measurements confirmed that filtering out the harmonics of the pulse signal does not degrade the accuracy of pulse oximetry.

  17. Evaluation of technologies of parallel computers. Communication networks for a real-time triggering application for a high-energy physics experiment at CERN

    International Nuclear Information System (INIS)

    Hoertnagl, Ch.

    1997-12-01

    Experiments at the future Large Hadron Collider (LHC) at CERN will be faced with an extraordinary challenge of event selection in real time. The primary event rate, equal to the bunch crossing frequency of 40 MHz, will have to be reduced by a factor of almost one-in-a-million in order to reveal traces of rare physics processes from an abundant background. This work presents various contributions to ongoing feasibility studies concerning the possible use of commercial technologies from the proximities of parallel computers and their communication networks for the second trigger stage, which faces an average data input rate of 100 kHz. Studies in this thesis apply a combination of methodologies, namely the build-up of lab-scale prototype implementations (including their exposition to test beam runs), algorithm development, technology tracking and benchmarking, as well as discrete event simulation. The main contribution consists of several technology case studies, which are based on the exploration of a set of standard benchmark programs for revealing simple parameters for characterizing delays during communication. Studied technologies include the communication sub-system of the Meiko CS-2, Asynchronous Transfer Mode (ATM), MEMORY CHANNEL, and Scalable Coherent Interface (SCI); all could be considered typical for candidate technologies. The discussion sheds light on the relative benefits and costs associated with different parallel programming models, in general, and with the use of message-passing libraries, such as Message Passing Interface (MPI), in particular. Best observed end-user-to-end-user latencies were ∼ 10 μs, best asymptotic bandwidths were ∼ 70 MByte/s. Typical sub-patterns of communication that have to be applied in the second trigger stage were sustained at ∼ 13 kHz, using today's technologies in realistic embeddings. (author)

  18. BECSI: Bandwidth Efficient Certificate Status Information Distribution Mechanism for VANETs

    Directory of Open Access Journals (Sweden)

    Carlos Gañán

    2013-01-01

    Full Text Available Certificate revocation is a challenging task, especiallyin mobile network environments such as vehicular ad Hoc networks (VANETs.According to the IEEE 1609.2 security standard for VANETs, public keyinfrastructure (PKI will provide this functionality by means of certificate revocation lists (CRLs.When a certificate authority (CAneeds to revoke a certificate, itglobally distributes CRLs.Transmitting these lists pose a problem as they require high update frequencies and a lot of bandwidth. In this article, we propose BECSI, aBandwidth Efficient Certificate Status Informationmechanism to efficiently distributecertificate status information (CSI in VANETs.By means of Merkle hash trees (MHT, BECSI allowsto retrieve authenticated CSI not onlyfrom the infrastructure but also from vehicles actingas mobile repositories.Since these MHTs are significantly smaller than the CRLs, BECSIreduces the load on the CSI repositories and improves the response time for the vehicles.Additionally, BECSI improves the freshness of the CSIby combining the use of delta-CRLs with MHTs.Thus, vehicles that have cached the most current CRLcan download delta-CRLs to have a complete list of revoked certificates.Once a vehicle has the whole list of revoked certificates, it can act as mobile repository.

  19. Improving microwave antenna gain and bandwidth with phase compensation metasurface

    Directory of Open Access Journals (Sweden)

    Ke Chen

    2015-06-01

    Full Text Available Metasurface, as a planar version of artificial metamaterial, provide an effective way to manipulate electromagnetic wave propagation. Here, we present a transparent metasurface for compensating the out-of-phase radiation from a microstrip patch antenna to improve its radiation gain and bandwidth. Based on the equivalence principle of Huygens’ surface, we propose metasurface composed of both inductive and capacitive resonant elements which could produce high transmission with variable phase characteristics. Such metasurface mounted on a patch antenna can transform the spherical-like phase profile generated from the patch into an in-phase planar one. A prototype antenna has been fabricated and validated the squeezed radiation pattern with suppressed sidelobes as well as enhanced impedance bandwidth due to strong near-field coupling. As operating at around 5.7 GHz, the proposed antenna may have potential application in wireless communication systems especially for point-to-point data transmission. It is believed that the design methodology could also be scaled to other frequency bands such as millimeter or terahertz wave.

  20. Ionospheric Coherence Bandwidth Measurements in the Lower VHF Frequency Range

    Science.gov (United States)

    Suszcynsky, D. M.; Light, M. E.; Pigue, M. J.

    2015-12-01

    The United States Department of Energy's Radio Frequency Propagation (RFProp) experiment consists of a satellite-based radio receiver suite to study various aspects of trans-ionospheric signal propagation and detection in four frequency bands, 2 - 55 MHz, 125 - 175 MHz, 365 - 415 MHz and 820 - 1100 MHz. In this paper, we present simultaneous ionospheric coherence bandwidth and S4 scintillation index measurements in the 32 - 44 MHz frequency range collected during the ESCINT equatorial scintillation experiment. 40-MHz continuous wave (CW) and 32 - 44 MHz swept frequency signals were transmitted simultaneously to the RFProp receiver suite from the Reagan Test Site at Kwajalein Atoll in the Marshall Islands (8.7° N, 167.7° E) in three separate campaigns during the 2014 and 2015 equinoxes. Results show coherence bandwidths as small as ~ 1 kHz for strong scintillation (S4 > 0.7) and indicate a high degree of ionospheric variability and irregularity on 10-m spatial scales. Spread-Doppler clutter effects arising from preferential ray paths to the satellite due to refraction off of isolated density irregularities are also observed and are dominant at low elevation angles. The results are compared to previous measurements and available scaling laws.

  1. Research and development of a gaseous detector PIM (parallel ionization multiplier) dedicated to particle tracking under high hadron rates

    International Nuclear Information System (INIS)

    Beucher, J.

    2007-10-01

    PIM (Parallel Ionization Multiplier) is a multi-stage micro-pattern gaseous detector using micro-meshes technology. This new device, based on Micromegas (micro-mesh gaseous structure) detector principle of operation, offers good characteristics for minimum ionizing particles track detection. However, this kind of detectors placed in hadron environment suffers discharges which degrade sensibly the detection efficiency and account for hazard to the front-end electronics. In order to minimize these strong events, it is convenient to perform charges multiplication by several successive steps. Within the framework of a European hadron physics project we have investigated the multi-stage PIM detector for high hadrons flux application. For this part of research and development, a systematic study for many geometrical configurations of a two amplification stages separated with a transfer space operated with the gaseous mixture Ne + 10% CO 2 has been performed. Beam tests realised with high energy hadrons at CERN facility have given that discharges probability could be strongly reduced with a suitable PIM device. A discharges rate lower to 10 9 by incident hadron and a spatial resolution of 51 μm have been measured at the beginning efficiency plateau (>96 %) operating point. (author)

  2. Parallel Sequencing of Expressed Sequence Tags from Two Complementary DNA Libraries for High and Low Phosphorus Adaptation in Common Beans

    Directory of Open Access Journals (Sweden)

    Matthew W. Blair

    2011-11-01

    Full Text Available Expressed sequence tags (ESTs have proven useful for gene discovery in many crops. In this work, our objective was to construct complementary DNA (cDNA libraries from root tissues of common beans ( L. grown under low and high P hydroponic conditions and to conduct EST sequencing and comparative analyses of the libraries. Expressed sequence tag analysis of 3648 clones identified 2372 unigenes, of which 1591 were annotated as known genes while a total of 465 unigenes were not associated with any known gene. Unigenes with hits were categorized according to biological processes, molecular function, and cellular compartmentalization. Given the young tissue used to make the root libraries, genes for catalytic activity and binding were highly expressed. Comparisons with previous root EST sequencing and between the two libraries made here resulted in a set of genes to study further for differential gene expression and adaptation to low P, such as a 14 kDa praline-rich protein, a metallopeptidase, tonoplast intrinsic protein, adenosine triphosphate (ATP citrate synthase, and cell proliferation genes expressed in the low P treated plants. Given that common beans are often grown on acid soils of the tropics and subtropics that are usually low in P these genes and the two parallel libraries will be useful for selection for better uptake of this essential macronutrient. The importance of EST generation for common bean root tissues under low P and other abiotic soil stresses is also discussed.

  3. Dynamic perception: Some theorems about the possibility of parallel pattern recognition with an application to high energy physics

    International Nuclear Information System (INIS)

    Perrone, A.; Basti, G.

    1994-01-01

    In the context of M. Minsky's and S. Papert's theorems on the impossibility of evaluating simple linear predicates by parallel architectures the authors want to show how these limitations can be avoided by introducing a generalized input-dependent preprocessing technique that does not suppose any a-priori knowledge of input like in classical input filtering procedures. This technique can be formalized in a very general way and can be also deduced by metamathematical arguments. A further development of the same technique can be applied at level of learning procedure to introduce in such a way the complete notion of open-quotes dynamic perceptronclose quotes. From the experimental standpoint, they show two applications of the open-quotes dynamic perceptronclose quotes in particle track recognition in high-energy accelerators. Firstly, they show the amazing improvement of performances that can be obtained in a perceptron architecture with classical learning by adding their open-quotes dynamicclose quotes pre-processing technique, already introduced last year in another paper presented at this Conference. Secondly, they show the results of this technique extended also at the level of learning procedure always applied to the problem of particle track recognition. This work is a part of open-quotes Feniceclose quotes international collaboration supported by INFN (National Institute for Nuclear Physics) devoted to the study of the time-like electromagnetic form factor of neutrons obtained by electron-positron high energy collisions in ADONE (Frascati, Rome) storage ring

  4. Bandwidth Impacts of Localizing Peer-to-Peer IP Video Traffic in Access and Aggregation Networks

    Directory of Open Access Journals (Sweden)

    Kerpez Kenneth

    2008-01-01

    Full Text Available Abstract This paper examines the burgeoning impact of peer-to-peer (P2P traffic IP video traffic. High-quality IPTV or Internet TV has high-bandwidth requirements, and P2P IP video could severely strain broadband networks. A model for the popularity of video titles is given, showing that some titles are very popular and will often be available locally; making localized P2P attractive for video titles. The bandwidth impacts of localizing P2P video to try and keep traffic within a broadband access network area or within a broadband access aggregation network area are examined. Results indicate that such highly localized P2P video can greatly lower core bandwidth usage.

  5. Bandwidth Impacts of Localizing Peer-to-Peer IP Video Traffic in Access and Aggregation Networks

    Directory of Open Access Journals (Sweden)

    Kenneth Kerpez

    2008-10-01

    Full Text Available This paper examines the burgeoning impact of peer-to-peer (P2P traffic IP video traffic. High-quality IPTV or Internet TV has high-bandwidth requirements, and P2P IP video could severely strain broadband networks. A model for the popularity of video titles is given, showing that some titles are very popular and will often be available locally; making localized P2P attractive for video titles. The bandwidth impacts of localizing P2P video to try and keep traffic within a broadband access network area or within a broadband access aggregation network area are examined. Results indicate that such highly localized P2P video can greatly lower core bandwidth usage.

  6. Investigating the influence of chromatic aberration and optical illumination bandwidth on fundus imaging in rats

    Science.gov (United States)

    Li, Hao; Liu, Wenzhong; Zhang, Hao F.

    2015-10-01

    Rodent models are indispensable in studying various retinal diseases. Noninvasive, high-resolution retinal imaging of rodent models is highly desired for longitudinally investigating the pathogenesis and therapeutic strategies. However, due to severe aberrations, the retinal image quality in rodents can be much worse than that in humans. We numerically and experimentally investigated the influence of chromatic aberration and optical illumination bandwidth on retinal imaging. We confirmed that the rat retinal image quality decreased with increasing illumination bandwidth. We achieved the retinal image resolution of 10 μm using a 19 nm illumination bandwidth centered at 580 nm in a home-built fundus camera. Furthermore, we observed higher chromatic aberration in albino rat eyes than in pigmented rat eyes. This study provides a design guide for high-resolution fundus camera for rodents. Our method is also beneficial to dispersion compensation in multiwavelength retinal imaging applications.

  7. Dynamic file-access characteristics of a production parallel scientific workload

    Science.gov (United States)

    Kotz, David; Nieuwejaar, Nils

    1994-01-01

    Multiprocessors have permitted astounding increases in computational performance, but many cannot meet the intense I/O requirements of some scientific applications. An important component of any solution to this I/O bottleneck is a parallel file system that can provide high-bandwidth access to tremendous amounts of data in parallel to hundreds or thousands of processors. Most successful systems are based on a solid understanding of the expected workload, but thus far there have been no comprehensive workload characterizations of multiprocessor file systems. This paper presents the results of a three week tracing study in which all file-related activity on a massively parallel computer was recorded. Our instrumentation differs from previous efforts in that it collects information about every I/O request and about the mix of jobs running in a production environment. We also present the results of a trace-driven caching simulation and recommendations for designers of multiprocessor file systems.

  8. Parallel transport studies of high-Z impurities in the core of Alcator C-Mod plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Reinke, M. L.; Hutchinson, I. H.; Rice, J. E.; Greenwald, M.; Howard, N. T.; Hubbard, A.; Hughes, J. W.; Terry, J. L.; Wolfe, S. M. [MIT-Plasma Science and Fusion Center Cambridge, Massachusetts 02139 (United States)

    2013-05-15

    Measurements of poloidal variation, ñ{sub z}/, in high-Z impurity density have been made using photodiode arrays sensitive to vacuum ultraviolet and soft x-ray emission in Alcator C-Mod plasmas. In/out asymmetries in the range of −0.2<0.3 are observed for r/a<0.8, and accumulation on both the high-field side, n{sub z,cos}<0, and low-field side, n{sub z,cos}>0, of a flux surface is found to be well described by a combination of centrifugal, poloidal electric field, and ion-impurity friction effects. Up/down asymmetries, −0.05<0.10, are observed over 0.50 corresponding to accumulation opposite the ion ∇B drift direction. Measurements of the up/down asymmetry of molybdenum are found to disagree with predictions from recent neoclassical theory in the trace limit, n{sub z}Z{sup 2}/n{sub i}≪1. Non-trace levels of impurities are expected to modify the main-ion poloidal flow and thus change friction-driven impurity density asymmetries and impurity poloidal rotation, v{sub θ,z}. Artificially modifying main-ion flow in parallel transport simulations is shown to impact both ñ{sub z}/ and v{sub θ,z}, but simultaneous agreement between measured and predicted up/down and in/out asymmetry as well as impurity poloidal rotation is not possible for these C-Mod data. This link between poloidal flow and poloidal impurity density variation outlines a more stringent test for parallel neoclassical transport theory than has previously been performed. Measurement and computational techniques specific to the study of poloidal impurity asymmetry physics are discussed as well.

  9. An Overview of High-performance Parallel Big Data transfers over multiple network channels with Transport Layer Security (TLS) and TLS plus Perfect Forward Secrecy (PFS)

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Chin [SLAC National Accelerator Lab., Menlo Park, CA (United States); Corttrell, R. A. [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-05-06

    This Technical Note provides an overview of high-performance parallel Big Data transfers with and without encryption for data in-transit over multiple network channels. It shows that with the parallel approach, it is feasible to carry out high-performance parallel "encrypted" Big Data transfers without serious impact to throughput. But other impacts, e.g. the energy-consumption part should be investigated. It also explains our rationales of using a statistics-based approach for gaining understanding from test results and for improving the system. The presentation is of high-level nature. Nevertheless, at the end we will pose some questions and identify potentially fruitful directions for future work.

  10. High-throughput automated parallel evaluation of zinc-based catalysts for the copolymerization of CHO and CO2 to polycarbonates

    NARCIS (Netherlands)

    Meerendonk, van W.J.; Duchateau, R.; Koning, C.E.; Gruter, G.J.M.

    2004-01-01

    Copolymn. of CO2 and oxiranes using a high-pressure autoclave typically allows one expt. per reactor per day. A high-throughput parallel setup was developed and validated for the copolymn. of CO2 and cyclohxene oxide (CHO) with two b-diiminato zinc complexes. The catalyst activity is affected by

  11. PIC Simulation of Laser Plasma Interactions with Temporal Bandwidths

    Science.gov (United States)

    Tsung, Frank; Weaver, J.; Lehmberg, R.

    2015-11-01

    We are performing particle-in-cell simulations using the code OSIRIS to study the effects of laser plasma interactions in the presence of temperal bandwidths under conditions relevant to current and future shock ignition experiments on the NIKE laser. Our simulations show that, for sufficiently large bandwidth, the saturation level, and the distribution of hot electrons, can be effected by the addition of temporal bandwidths (which can be accomplished in experiments using smoothing techniques such as SSD or ISI). We will show that temporal bandwidth along play an important role in the control of LPI's in these lasers and discuss future directions. This work is conducted under the auspices of NRL.

  12. Parallel Evolution of High-Level Aminoglycoside Resistance in Escherichia coli Under Low and High Mutation Supply Rates

    Directory of Open Access Journals (Sweden)

    Claudia Ibacache-Quiroga

    2018-03-01

    Full Text Available Antibiotic resistance is a major concern in public health worldwide, thus there is much interest in characterizing the mutational pathways through which susceptible bacteria evolve resistance. Here we use experimental evolution to explore the mutational pathways toward aminoglycoside resistance, using gentamicin as a model, under low and high mutation supply rates. Our results show that both normo and hypermutable strains of Escherichia coli are able to develop resistance to drug dosages > 1,000-fold higher than the minimal inhibitory concentration for their ancestors. Interestingly, such level of resistance was often associated with changes in susceptibility to other antibiotics, most prominently with increased resistance to fosfomycin. Whole-genome sequencing revealed that all resistant derivatives presented diverse mutations in five common genetic elements: fhuA, fusA and the atpIBEFHAGDC, cyoABCDE, and potABCD operons. Despite the large number of mutations acquired, hypermutable strains did not pay, apparently, fitness cost. In contrast to recent studies, we found that the mutation supply rate mainly affected the speed (tempo but not the pattern (mode of evolution: both backgrounds acquired the mutations in the same order, although the hypermutator strain did it faster. This observation is compatible with the adaptive landscape for high-level gentamicin resistance being relatively smooth, with few local maxima; which might be a common feature among antibiotics for which resistance involves multiple loci.

  13. Implementation of a Monte Carlo simulation environment for fully 3D PET on a high-performance parallel platform

    CERN Document Server

    Zaidi, H; Morel, Christian

    1998-01-01

    This paper describes the implementation of the Eidolon Monte Carlo program designed to simulate fully three-dimensional (3D) cylindrical positron tomographs on a MIMD parallel architecture. The original code was written in Objective-C and developed under the NeXTSTEP development environment. Different steps involved in porting the software on a parallel architecture based on PowerPC 604 processors running under AIX 4.1 are presented. Basic aspects and strategies of running Monte Carlo calculations on parallel computers are described. A linear decrease of the computing time was achieved with the number of computing nodes. The improved time performances resulting from parallelisation of the Monte Carlo calculations makes it an attractive tool for modelling photon transport in 3D positron tomography. The parallelisation paradigm used in this work is independent from the chosen parallel architecture

  14. Study on High Performance of MPI-Based Parallel FDTD from WorkStation to Super Computer Platform

    Directory of Open Access Journals (Sweden)

    Z. L. He

    2012-01-01

    Full Text Available Parallel FDTD method is applied to analyze the electromagnetic problems of the electrically large targets on super computer. It is well known that the more the number of processors the less computing time consumed. Nevertheless, with the same number of processors, computing efficiency is affected by the scheme of the MPI virtual topology. Then, the influence of different virtual topology schemes on parallel performance of parallel FDTD is studied in detail. The general rules are presented on how to obtain the highest efficiency of parallel FDTD algorithm by optimizing MPI virtual topology. To show the validity of the presented method, several numerical results are given in the later part. Various comparisons are made and some useful conclusions are summarized.

  15. A new model for volume recombination in plane-parallel chambers in pulsed fields of high dose-per-pulse.

    Science.gov (United States)

    Gotz, M; Karsch, L; Pawelke, J

    2017-11-01

    In order to describe the volume recombination in a pulsed radiation field of high dose-per-pulse this study presents a numerical solution of a 1D transport model of the liberated charges in a plane-parallel ionization chamber. In addition, measurements were performed on an Advanced Markus ionization chamber in a pulsed electron beam to obtain suitable data to test the calculation. The experiment used radiation pulses of 4 μs duration and variable dose-per-pulse values up to about 1 Gy, as well as pulses of variable duration up to 308 [Formula: see text] at constant dose-per-pulse values between 85 mGy and 400 mGy. Those experimental data were compared to the developed numerical model and existing descriptions of volume recombination. At low collection voltages the observed dose-per-pulse dependence of volume recombination can be approximated by the existing theory using effective parameters. However, at high collection voltages large discrepancies are observed. The developed numerical model shows much better agreement with the observations and is able to replicate the observed behavior over the entire range of dose-per-pulse values and collection voltages. Using the developed numerical model, the differences between observation and existing theory are shown to be the result of a large fraction of the charge being collected as free electrons and the resultant distortion of the electric field inside the chamber. Furthermore, the numerical solution is able to calculate recombination losses for arbitrary pulse durations in good agreement with the experimental data, an aspect not covered by current theory. Overall, the presented numerical solution of the charge transport model should provide a more flexible tool to describe volume recombination for high dose-per-pulse values as well as for arbitrary pulse durations and repetition rates.

  16. The use of coded PCR primers enables high-throughput sequencing of multiple homolog amplification products by 454 parallel sequencing.

    Directory of Open Access Journals (Sweden)

    Jonas Binladen

    2007-02-01

    Full Text Available The invention of the Genome Sequence 20 DNA Sequencing System (454 parallel sequencing platform has enabled the rapid and high-volume production of sequence data. Until now, however, individual emulsion PCR (emPCR reactions and subsequent sequencing runs have been unable to combine template DNA from multiple individuals, as homologous sequences cannot be subsequently assigned to their original sources.We use conventional PCR with 5'-nucleotide tagged primers to generate homologous DNA amplification products from multiple specimens, followed by sequencing through the high-throughput Genome Sequence 20 DNA Sequencing System (GS20, Roche/454 Life Sciences. Each DNA sequence is subsequently traced back to its individual source through 5'tag-analysis.We demonstrate that this new approach enables the assignment of virtually all the generated DNA sequences to the correct source once sequencing anomalies are accounted for (miss-assignment rate<0.4%. Therefore, the method enables accurate sequencing and assignment of homologous DNA sequences from multiple sources in single high-throughput GS20 run. We observe a bias in the distribution of the differently tagged primers that is dependent on the 5' nucleotide of the tag. In particular, primers 5' labelled with a cytosine are heavily overrepresented among the final sequences, while those 5' labelled with a thymine are strongly underrepresented. A weaker bias also exists with regards to the distribution of the sequences as sorted by the second nucleotide of the dinucleotide tags. As the results are based on a single GS20 run, the general applicability of the approach requires confirmation. However, our experiments demonstrate that 5'primer tagging is a useful method in which the sequencing power of the GS20 can be applied to PCR-based assays of multiple homologous PCR products. The new approach will be of value to a broad range of research areas, such as those of comparative genomics, complete mitochondrial

  17. Toward Bulk Synchronous Parallel-Based Machine Learning Techniques for Anomaly Detection in High-Speed Big Data Networks

    Directory of Open Access Journals (Sweden)

    Kamran Siddique

    2017-09-01

    Full Text Available Anomaly detection systems, also known as intrusion detection systems (IDSs, continuously monitor network traffic aiming to identify malicious actions. Extensive research has been conducted to build efficient IDSs emphasizing two essential characteristics. The first is concerned with finding optimal feature selection, while another deals with employing robust classification schemes. However, the advent of big data concepts in anomaly detection domain and the appearance of sophisticated network attacks in the modern era require some fundamental methodological revisions to develop IDSs. Therefore, we first identify two more significant characteristics in addition to the ones mentioned above. These refer to the need for employing specialized big data processing frameworks and utilizing appropriate datasets for validating system’s performance, which is largely overlooked in existing studies. Afterwards, we set out to develop an anomaly detection system that comprehensively follows these four identified characteristics, i.e., the proposed system (i performs feature ranking and selection using information gain and automated branch-and-bound algorithms respectively; (ii employs logistic regression and extreme gradient boosting techniques for classification; (iii introduces bulk synchronous parallel processing to cater computational requirements of high-speed big data networks; and; (iv uses the Infromation Security Centre of Excellence, of the University of Brunswick real-time contemporary dataset for performance evaluation. We present experimental results that verify the efficacy of the proposed system.

  18. Wideband and flat-gain amplifier based on high concentration erbium-doped fibres in parallel double-pass configuration

    International Nuclear Information System (INIS)

    Hamida, B A; Cheng, X S; Harun, S W; Naji, A W; Arof, H; Al-Khateeb, W; Khan, S; Ahmad, H

    2012-01-01

    A wideband and flat gain erbium-doped fibre amplifier (EDFA) is demonstrated using a hybrid gain medium of a zirconiabased erbium-doped fibre (Zr-EDF) and a high concentration erbium-doped fibre (EDF). The amplifier has two stages comprising a 2-m-long ZEDF and 9-m-long EDF optimised for C- and L-band operations, respectively, in a double-pass parallel configuration. A chirp fibre Bragg grating (CFBG) is used in both stages to ensure double propagation of the signal and thus to increase the attainable gain in both C- and L-band regions. At an input signal power of 0 dBm, a flat gain of 15 dB is achieved with a gain variation of less than 0.5 dB within a wide wavelength range from 1530 to 1605 nm. The corresponding noise figure varies from 6.2 to 10.8 dB within this wavelength region.

  19. LightForce Photon-Pressure Collision Avoidance: Updated Efficiency Analysis Utilizing a Highly Parallel Simulation Approach

    Science.gov (United States)

    Stupl, Jan; Faber, Nicolas; Foster, Cyrus; Yang, Fan Yang; Nelson, Bron; Aziz, Jonathan; Nuttall, Andrew; Henze, Chris; Levit, Creon

    2014-01-01

    This paper provides an updated efficiency analysis of the LightForce space debris collision avoidance scheme. LightForce aims to prevent collisions on warning by utilizing photon pressure from ground based, commercial off the shelf lasers. Past research has shown that a few ground-based systems consisting of 10 kilowatt class lasers directed by 1.5 meter telescopes with adaptive optics could lower the expected number of collisions in Low Earth Orbit (LEO) by an order of magnitude. Our simulation approach utilizes the entire Two Line Element (TLE) catalogue in LEO for a given day as initial input. Least-squares fitting of a TLE time series is used for an improved orbit estimate. We then calculate the probability of collision for all LEO objects in the catalogue for a time step of the simulation. The conjunctions that exceed a threshold probability of collision are then engaged by a simulated network of laser ground stations. After those engagements, the perturbed orbits are used to re-assess the probability of collision and evaluate the efficiency of the system. This paper describes new simulations with three updated aspects: 1) By utilizing a highly parallel simulation approach employing hundreds of processors, we have extended our analysis to a much broader dataset. The simulation time is extended to one year. 2) We analyze not only the efficiency of LightForce on conjunctions that naturally occur, but also take into account conjunctions caused by orbit perturbations due to LightForce engagements. 3) We use a new simulation approach that is regularly updating the LightForce engagement strategy, as it would be during actual operations. In this paper we present our simulation approach to parallelize the efficiency analysis, its computational performance and the resulting expected efficiency of the LightForce collision avoidance system. Results indicate that utilizing a network of four LightForce stations with 20 kilowatt lasers, 85% of all conjunctions with a

  20. Design optimization of the distributed modal filtering rod fiber for increasing single mode bandwidth

    DEFF Research Database (Denmark)

    Jørgensen, Mette Marie; Petersen, Sidsel Rübner; Laurila, Marko

    2012-01-01

    . Large preform tolerances are compensated during the fiber draw resulting in ultra low NA fibers with very large cores. In this paper, design optimization of the SM bandwidth of the DMF rod fiber is presented. Analysis of band gap properties results in a fourfold increase of the SM bandwidth compared...... LMA fiber amplifiers having high pump absorption through a pump cladding that is decoupled from the outer fiber. However, achieving ultra low NA for single-mode (SM) guidance is challenging, and thus different design strategies must be applied to filter out higher order modes (HOMs). The novel...... distributed modal filtering (DMF) design presented here enables SM guidance, and previous results have shown a SM mode field diameter of 60 μm operating in a 20 nm SM bandwidth. The DMF rod fiber has high index ring-shaped inclusions acting as resonators enabling SM guidance through modal filtering of HOMs...

  1. Parallel computation

    International Nuclear Information System (INIS)

    Jejcic, A.; Maillard, J.; Maurel, G.; Silva, J.; Wolff-Bacha, F.

    1997-01-01

    The work in the field of parallel processing has developed as research activities using several numerical Monte Carlo simulations related to basic or applied current problems of nuclear and particle physics. For the applications utilizing the GEANT code development or improvement works were done on parts simulating low energy physical phenomena like radiation, transport and interaction. The problem of actinide burning by means of accelerators was approached using a simulation with the GEANT code. A program of neutron tracking in the range of low energies up to the thermal region has been developed. It is coupled to the GEANT code and permits in a single pass the simulation of a hybrid reactor core receiving a proton burst. Other works in this field refers to simulations for nuclear medicine applications like, for instance, development of biological probes, evaluation and characterization of the gamma cameras (collimators, crystal thickness) as well as the method for dosimetric calculations. Particularly, these calculations are suited for a geometrical parallelization approach especially adapted to parallel machines of the TN310 type. Other works mentioned in the same field refer to simulation of the electron channelling in crystals and simulation of the beam-beam interaction effect in colliders. The GEANT code was also used to simulate the operation of germanium detectors designed for natural and artificial radioactivity monitoring of environment

  2. Gain-switched, Yb-doped, all-fiber laser with narrow bandwidth

    DEFF Research Database (Denmark)

    Larsen, Casper; Giesberts, Martin; Nyga, Sebastian

    2013-01-01

    We demonstrate that an all-fiber, narrow bandwidth, high pulse energy pulsed laser can be constructed from commercially available components by applying gain-switching. After single-stage amplification the pulses are frequency doubled in ppSLT with high efficiency....

  3. Quantitative and Selective Analysis of Feline Growth Related Proteins Using Parallel Reaction Monitoring High Resolution Mass Spectrometry.

    Directory of Open Access Journals (Sweden)

    Mårten Sundberg

    Full Text Available Today immunoassays are widely used in veterinary medicine, but lack of species specific assays often necessitates the use of assays developed for human applications. Mass spectrometry (MS is an attractive alternative due to high specificity and versatility, allowing for species-independent analysis. Targeted MS-based quantification methods are valuable complements to large scale shotgun analysis. A method referred to as parallel reaction monitoring (PRM, implemented on Orbitrap MS, has lately been presented as an excellent alternative to more traditional selected reaction monitoring/multiple reaction monitoring (SRM/MRM methods. The insulin-like growth factor (IGF-system is not well described in the cat but there are indications of important differences between cats and humans. In feline medicine IGF-I is mainly analyzed for diagnosis of growth hormone disorders but also for research, while the other proteins in the IGF-system are not routinely analyzed within clinical practice. Here, a PRM method for quantification of IGF-I, IGF-II, IGF binding protein (BP -3 and IGFBP-5 in feline serum is presented. Selective quantification was supported by the use of a newly launched internal standard named QPrEST™. Homology searches demonstrated the possibility to use this standard of human origin for quantification of the targeted feline proteins. Excellent quantitative sensitivity at the attomol/μL (pM level and selectivity were obtained. As the presented approach is very generic we show that high resolution mass spectrometry in combination with PRM and QPrEST™ internal standards is a versatile tool for protein quantitation across multispecies.

  4. High-accuracy and robust face recognition system based on optical parallel correlator using a temporal image sequence

    Science.gov (United States)

    Watanabe, Eriko; Ishikawa, Mami; Ohta, Maiko; Kodate, Kashiko

    2005-09-01

    Face recognition is used in a wide range of security systems, such as monitoring credit card use, searching for individuals with street cameras via Internet and maintaining immigration control. There are still many technical subjects under study. For instance, the number of images that can be stored is limited under the current system, and the rate of recognition must be improved to account for photo shots taken at different angles under various conditions. We implemented a fully automatic Fast Face Recognition Optical Correlator (FARCO) system by using a 1000 frame/s optical parallel correlator designed and assembled by us. Operational speed for the 1: N (i.e. matching a pair of images among N, where N refers to the number of images in the database) identification experiment (4000 face images) amounts to less than 1.5 seconds, including the pre/post processing. From trial 1: N identification experiments using FARCO, we acquired low error rates of 2.6% False Reject Rate and 1.3% False Accept Rate. By making the most of the high-speed data-processing capability of this system, much more robustness can be achieved for various recognition conditions when large-category data are registered for a single person. We propose a face recognition algorithm for the FARCO while employing a temporal image sequence of moving images. Applying this algorithm to a natural posture, a two times higher recognition rate scored compared with our conventional system. The system has high potential for future use in a variety of purposes such as search for criminal suspects by use of street and airport video cameras, registration of babies at hospitals or handling of an immeasurable number of images in a database.

  5. Receiver bandwidth effects on complex modulation and detection using directly modulated lasers.

    Science.gov (United States)

    Yuan, Feng; Che, Di; Shieh, William

    2016-05-01

    Directly modulated lasers (DMLs) have long been employed for short- and medium-reach optical communications due to their low cost. Recently, a new modulation scheme called complex modulated DMLs has been demonstrated showing a significant optical signal to noise ratio sensitivity enhancement compared with the traditional intensity-only detection scheme. However, chirp-induced optical spectrum broadening is inevitable in complex modulated systems, which may imply a need for high-bandwidth receivers. In this Letter, we study the impact of receiver bandwidth effects on the performance of complex modulation and coherent detection systems based on DMLs. We experimentally demonstrate that such systems exhibit a reasonable tolerance for the reduced receiver bandwidth. For 10 Gbaud 4-level pulse amplitude modulation signals, the required electrical bandwidth is as low as 8.5 and 7.5 GHz for 7% and 20% forward error correction, respectively. Therefore, it is feasible to realize DML-based complex modulated systems using cost-effective receivers with narrow bandwidth.

  6. Studies of bandwidth dependence of laser plasma instabilities driven by the Nike laser

    Science.gov (United States)

    Weaver, J.; Kehne, D.; Obenschain, S.; Serlin, V.; Schmitt, A. J.; Oh, J.; Lehmberg, R. H.; Brown, C. M.; Seely, J.; Feldman, U.

    2012-10-01

    Experiments at the Nike laser facility of the Naval Research Laboratory are exploring the influence of laser bandwidth on laser plasma instabilities (LPI) driven by a deep ultraviolet pump (248 nm) that incorporates beam smoothing by induced spatial incoherence (ISI). In early ISI studies with longer wavelength Nd:glass lasers (1054 nm and 527 nm),footnotetextObenschain, PRL 62(1989);Mostovych, PRL 62(1987);Peyser, Phys. Fluids B 3(1991). stimulated Raman scattering, stimulated Brillouin scattering, and the two plasmon decay instability were reduced when wide bandwidth ISI (δν/ν˜0.03-0.19%) pulses irradiated targets at moderate to high intensities (10^14-10^15 W/cm^2). The current studies will compare the emission signatures of LPI from planar CH targets during Nike operation at large bandwidth (δν˜1THz) to observations for narrower bandwidth operation (δν˜0.1-0.3THz). These studies will help clarify the relative importance of the short wavelength and wide bandwidth to the increased LPI intensity thresholds observed at Nike. New pulse shapes are being used to generate plasmas with larger electron density scale-lengths that are closer to conditions during pellet implosions for direct drive inertial confinement fusion.

  7. A Hybrid ACO Approach to the Matrix Bandwidth Minimization Problem

    Science.gov (United States)

    Pintea, Camelia-M.; Crişan, Gloria-Cerasela; Chira, Camelia

    The evolution of the human society raises more and more difficult endeavors. For some of the real-life problems, the computing time-restriction enhances their complexity. The Matrix Bandwidth Minimization Problem (MBMP) seeks for a simultaneous permutation of the rows and the columns of a square matrix in order to keep its nonzero entries close to the main diagonal. The MBMP is a highly investigated {NP}-complete problem, as it has broad applications in industry, logistics, artificial intelligence or information recovery. This paper describes a new attempt to use the Ant Colony Optimization framework in tackling MBMP. The introduced model is based on the hybridization of the Ant Colony System technique with new local search mechanisms. Computational experiments confirm a good performance of the proposed algorithm for the considered set of MBMP instances.

  8. Wideband aperture array using RF channelizers and massively parallel digital 2D IIR filterbank

    Science.gov (United States)

    Sengupta, Arindam; Madanayake, Arjuna; Gómez-García, Roberto; Engeberg, Erik D.

    2014-05-01

    Wideband receive-mode beamforming applications in wireless location, electronically-scanned antennas for radar, RF sensing, microwave imaging and wireless communications require digital aperture arrays that offer a relatively constant far-field beam over several octaves of bandwidth. Several beamforming schemes including the well-known true time-delay and the phased array beamformers have been realized using either finite impulse response (FIR) or fast Fourier transform (FFT) digital filter-sum based techniques. These beamforming algorithms offer the desired selectivity at the cost of a high computational complexity and frequency-dependant far-field array patterns. A novel approach to receiver beamforming is the use of massively parallel 2-D infinite impulse response (IIR) fan filterbanks for the synthesis of relatively frequency independent RF beams at an order of magnitude lower multiplier complexity compared to FFT or FIR filter based conventional algorithms. The 2-D IIR filterbanks demand fast digital processing that can support several octaves of RF bandwidth, fast analog-to-digital converters (ADCs) for RF-to-bits type direct conversion of wideband antenna element signals. Fast digital implementation platforms that can realize high-precision recursive filter structures necessary for real-time beamforming, at RF radio bandwidths, are also desired. We propose a novel technique that combines a passive RF channelizer, multichannel ADC technology, and single-phase massively parallel 2-D IIR digital fan filterbanks, realized at low complexity using FPGA and/or ASIC technology. There exists native support for a larger bandwidth than the maximum clock frequency of the digital implementation technology. We also strive to achieve More-than-Moore throughput by processing a wideband RF signal having content with N-fold (B = N Fclk/2) bandwidth compared to the maximum clock frequency Fclk Hz of the digital VLSI platform under consideration. Such increase in bandwidth is

  9. Using the Eclipse Parallel Tools Platform to Assist Earth Science Model Development and Optimization on High Performance Computers

    Science.gov (United States)

    Alameda, J. C.

    2011-12-01

    Development and optimization of computational science models, particularly on high performance computers, and with the advent of ubiquitous multicore processor systems, practically on every system, has been accomplished with basic software tools, typically, command-line based compilers, debuggers, performance tools that have not changed substantially from the days of serial and early vector computers. However, model complexity, including the complexity added by modern message passing libraries such as MPI, and the need for hybrid code models (such as openMP and MPI) to be able to take full advantage of high performance computers with an increasing core count per shared memory node, has made development and optimization of such codes an increasingly arduous task. Additional architectural developments, such as many-core processors, only complicate the situation further. In this paper, we describe how our NSF-funded project, "SI2-SSI: A Productive and Accessible Development Workbench for HPC Applications Using the Eclipse Parallel Tools Platform" (WHPC) seeks to improve the Eclipse Parallel Tools Platform, an environment designed to support scientific code development targeted at a diverse set of high performance computing systems. Our WHPC project to improve Eclipse PTP takes an application-centric view to improve PTP. We are using a set of scientific applications, each with a variety of challenges, and using PTP to drive further improvements to both the scientific application, as well as to understand shortcomings in Eclipse PTP from an application developer perspective, to drive our list of improvements we seek to make. We are also partnering with performance tool providers, to drive higher quality performance tool integration. We have partnered with the Cactus group at Louisiana State University to improve Eclipse's ability to work with computational frameworks and extremely complex build systems, as well as to develop educational materials to incorporate into

  10. Bandwidth selection in smoothing functions | Kibua | East African ...

    African Journals Online (AJOL)

    ... inexpensive and, hence, worth adopting. We argue that the bandwidth parameter is determined by two factors: the kernel function and the length of the smoothing region. We give an illustrative example of its application using real data. Keywords: Kernel, Smoothing functions, Bandwidth > East African Journal of Statistics ...

  11. Variable Bandwidth Analog Channel Filters for Software Defined Radio

    NARCIS (Netherlands)

    Arkesteijn, V.J.; Klumperink, Eric A.M.; Nauta, Bram

    2001-01-01

    An important aspect of Software Defined Radio is the ability to define the bandwidth of the filter that selects the desired channel. This paper first explains the importance of channel filtering. Then the advantage of analog channel filtering with a variable bandwidth in a Software Defined Radio is

  12. Fluid Limits for Bandwidth-Sharing Networks in Overload.

    NARCIS (Netherlands)

    Borst, S.; Egorova, R.; Zwart, A.P.

    2014-01-01

    Bandwidth-sharing networks as considered by Roberts and Massoulié [28] (Roberts JW, Massoulié L (1998) Bandwidth sharing and admission control for elastic traffic. Proc. ITC Specialist Seminar, Yokohama, Japan) provide a natural modeling framework for describing the dynamic flow-level interaction

  13. Fluid limits for bandwidth-sharing networks in overload

    NARCIS (Netherlands)

    Borst, S.C.; Egorova, R.R.; Zwart, B.

    2014-01-01

    Bandwidth-sharing networks as considered by Roberts and Massoulié [28] (Roberts JW, Massoulié L (1998) Bandwidth sharing and admission control for elastic traffic. Proc. ITC Specialist Seminar, Yokohama, Japan) provide a natural modeling framework for describing the dynamic flow-level interaction

  14. 47 CFR 74.535 - Emission and bandwidth.

    Science.gov (United States)

    2010-10-01

    ... digital modulation in paragraph (a) of this section, the resolution bandwidth (BRES) of the measuring...), adjusted upward to the nearest greater resolution bandwidth available on the measuring equipment. In all... frequency energy outside the assigned channel. Upon notice by the FCC to the station licensee that...

  15. Optimal Bandwidth Selection in Observed-Score Kernel Equating

    Science.gov (United States)

    Häggström, Jenny; Wiberg, Marie

    2014-01-01

    The selection of bandwidth in kernel equating is important because it has a direct impact on the equated test scores. The aim of this article is to examine the use of double smoothing when selecting bandwidths in kernel equating and to compare double smoothing with the commonly used penalty method. This comparison was made using both an equivalent…

  16. Metamaterial composite bandpass filter with an ultra-broadband rejection bandwidth of up to 240 terahertz

    DEFF Research Database (Denmark)

    Strikwerda, Andrew; Zalkovskij, Maksim; Lorenzen, Dennis Lund

    2014-01-01

    We present a metamaterial, consisting of a cross structure and a metal mesh filter, that forms a composite with greater functional bandwidth than any terahertz (THz) metamaterial to date. Metamaterials traditionally have a narrow usable bandwidth that is much smaller than common THz sources......, such as photoconductive antennas and difference frequency generation. The composite structure shown here expands the usable bandwidth to exceed that of current THz sources. To highlight the applicability of this combination, we demonstrate a series of bandpass filters with only a single pass band, with a central...... frequency (f) that is scalable from 0.86–8.51 THz, that highly extinguishes other frequencies up to >240 THz. The performance of these filters is demonstrated in experiment, using both air biased coherent detection and a Fourier transform infrared spectrometer (FTIR), as well as in simulation. We present...

  17. Amplifying modeling for broad bandwidth pulse in Nd:glass based on hybrid-broaden mechanism

    International Nuclear Information System (INIS)

    Sujingqin; Lanqin, L; Wenyi, W; Feng, J; Xiaofeng, W; Xiaomin, Z; Bin, L

    2008-01-01

    In this paper, the cross relaxation time is proposed to combine the homogeneous and inhomogeneous broaden mechanism for broad bandwidth pulse amplification model. The corresponding velocity equation, which can describe the response of inverse population on upper and low energy level of gain media to different frequency of pulse, is also put forward. The gain saturation and energy relaxation effect are also included in the velocity equation. Code named CPAP has been developed to simulate the amplifying process of broad bandwidth pulse in multi-pass laser system. The amplifying capability of multi-pass laser system is evaluated and gain narrowing and temporal shape distortion are also investigated when bandwidth of pulse and cross relaxation time of gain media are different. Results can benefit the design of high-energy PW laser system in LFRC, CAEP

  18. Amplifying modeling for broad bandwidth pulse in Nd:glass based on hybrid-broaden mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Sujingqin; Lanqin, L; Wenyi, W; Feng, J; Xiaofeng, W; Xiaomin, Z [Research Center of Laser Fusion, China Academy of Engineering Physics, P. O. Box 919-988, Mianyang, China, 621900 (China); Bin, L [School of Computer and Communication Engineering, Southwest Jiaotong University, Chengdu. China, 610031 (China)], E-mail: sujingqin@tom.com

    2008-05-15

    In this paper, the cross relaxation time is proposed to combine the homogeneous and inhomogeneous broaden mechanism for broad bandwidth pulse amplification model. The corresponding velocity equation, which can describe the response of inverse population on upper and low energy level of gain media to different frequency of pulse, is also put forward. The gain saturation and energy relaxation effect are also included in the velocity equation. Code named CPAP has been developed to simulate the amplifying process of broad bandwidth pulse in multi-pass laser system. The amplifying capability of multi-pass laser system is evaluated and gain narrowing and temporal shape distortion are also investigated when bandwidth of pulse and cross relaxation time of gain media are different. Results can benefit the design of high-energy PW laser system in LFRC, CAEP.

  19. Investigation of Diagonal Antenna-Chassis Mode in Mobile Terminal LTE MIMO Antennas for Bandwidth Enhancement

    DEFF Research Database (Denmark)

    Zhang, Shuai; Zhao, Kun; Ying, Zhinong

    2015-01-01

    mechanism of the mismatch of these three bandwidth ranges is also explained. Furthermore, the diagonal antenna-chassis mode is also studied for MIMO elements in the adjacent and diagonal corner locations. As a practical example, a wideband collocated LTE MIMO antenna is proposed and measured. It covers......A diagonal antenna-chassis mode is investigated in long-term evolution multiple-input-multiple-output (LTE MIMO) antennas. The MIMO bandwidth is defined in this paper as the overlap range of the low-envelope correlation coefficient, high total efficiency, and -6-dB impedance matching bandwidths...... the bands of 740960 and 1700-2700 MHz, where the total efficiencies are better than -3.4 and -1.8 dB, with lower than 0.5 and 0.1, respectively. The measurements agree well with the simulations. Since the proposed method only needs to modify the excitation locations of the MIMO elements on the chassis...

  20. HPDC ´12 : proceedings of the 21st ACM symposium on high-performance parallel and distributed computing, June 18-22, 2012, Delft, The Netherlands

    NARCIS (Netherlands)

    Epema, D.H.J.; Kielmann, T.; Ripeanu, M.

    2012-01-01

    Welcome to ACM HPDC 2012! This is the twenty-first year of HPDC and we are pleased to report that our community continues to grow in size, quality and reputation. The program consists of three days packed with presentations on the latest developments in high-performance parallel and distributed

  1. The Implementation Of Solid State Switches In A Parallel Configuration To Gain Output Current Capacity In A High Current Capacitive Discharge Unit (CDU).

    Energy Technology Data Exchange (ETDEWEB)

    Chaves, Mario Paul [Univ. of New Mexico, Albuquerque, NM (United States)

    2017-07-01

    For my project I have selected to research and design a high current pulse system, which will be externally triggered from a 5V pulse. The research will be conducted in the region of paralleling the solid state switches for a higher current output, as well as to see if there will be any other advantages in doing so. The end use of the paralleled solid state switches will be used on a Capacitive Discharge Unit (CDU). For the first part of my project, I have set my focus on the design of the circuit, selection of components, and simulation of the circuit.

  2. Theoretical study on the ultra-narrow bandwidth tunable atomic filter with electromagnetically induced transparency

    Science.gov (United States)

    Liu, Yang; Li, Shu-qing; Feng, Zhong-ying; Liu, Xiao-fei; Gao, Jin-yue

    2016-12-01

    To obtain the weak signal light detection from the high background noise, we present a theoretical study on the ultra-narrow bandwidth tunable atomic filter with electromagnetically induced transparency. In a three-level Λ -type atomic system in the rubidium D1 line, the bandwidth of the EIT atomic filter is narrowed to ~6.5 \\text{MHz} . And the single peak transmission of the filter can be up to 86% . Moreover, the transmission wavelength can be tuned by changing the coupling light frequency. This theoretical scheme can also be applied to other alkali atomic systems.

  3. Balanced steady-state free precession with parallel imaging gives distortion-free fMRI with high temporal resolution.

    Science.gov (United States)

    Chappell, Michael; Håberg, Asta K; Kristoffersen, Anders

    2011-01-01

    Research on the functions of the human brain requires that functional magnetic resonance imaging (MRI) moves towards producing images with less distortion and higher temporal and spatial resolution. This study compares passband balanced steady-state free precession (bSSFP) acquisitions with and without parallel imaging (PI) to investigate whether combining PI with this pulse sequence is a viable option for functional MRI. Such a novel combination has the potential to offer the distortion-free advantages of bSSFP with the reduced acquisition time of PI. Scans were done on a Philips 3T Intera, using the installed bSSFP pulse sequence, both with and without the sensitivity encoding (SENSE) PI option. The task was a visual flashing checkerboard, and the viewing window covered the visual cortex. Sensitivity comparisons with and without PI were done using the same manually drawn region of interest for each time course of the subject, and comparing the z-score summary statistics: number of voxels with z>2.3, the mean of those voxels, their 90th percentile and their maximum value. We show that PI greatly improves the temporal resolution in bSSFP, reducing the volume acquisition time by more than half in this study to 0.67 s with 3-mm isotropic voxels. At the same time, a statistically significant increase was found for the maximum z-score using bSSFP with PI as compared to without it (P=.02). This improvement can be understood in terms of physiological noise, as demonstrated by noise measurements. This produces observed increases in the overall temporal signal to noise of the functional time series, giving greater sensitivity to functional activations with PI. This study demonstrates for the first time the possibility of combining PI with bSSFP to achieve distortion-free functional images without loss of sensitivity and with high temporal resolution. Copyright © 2011 Elsevier Inc. All rights reserved.

  4. Synthesis and Evaluation of A High Precision 3D-Printed Ti6Al4V Compliant Parallel Manipulator

    Science.gov (United States)

    Pham, Minh Tuan; Teo, Tat Joo; Huat Yeo, Song; Wang, Pan; Nai, Mui Ling Sharon

    2017-12-01

    A novel 3D printed compliant parallel manipulator (CPM) with θX - θX - Z motions is presented in this paper. This CPM is synthesized using the beam-based method, a new structural optimization approach, to achieve optimized stiffness properties with targeted dynamic behavior. The CPM performs high non-actuating stiffness based on the predicted stiffness ratios of about 3600 for translations and 570 for rotations, while the dynamic response is fast with the targeted first resonant mode of 100Hz. A prototype of the synthesized CPM is fabricated using the electron beam melting (EBM) technology with Ti6Al4V material. Driven by three voice-coil (VC) motors, the CPM demonstrated a positioning resolution of 50nm along the Z axis and an angular resolution of ~0.3 “about the X and Y axes, the positioning accuracy is also good with the measured values of ±25.2nm and ±0.17” for the translation and rotations respectively. Experimental investigation also shows that this large workspace CPM has a first resonant mode of 98Hz and the stiffness behavior matches the prediction with the highest deviation of 11.2%. Most importantly, the full workspace of 10° × 10° × 7mm of the proposed CPM can be achieved, that demonstrates 3D printed compliant mechanisms can perform large elastic deformation. The obtained results show that CPMs printed by EBM technology have predictable mechanical characteristics and are applicable in precise positioning systems.

  5. The use of plane parallel ionization chambers in high energy electron and photon beams. An international code of practice for dosimetry

    International Nuclear Information System (INIS)

    1997-01-01

    Research on plane-parallel ionization chambers since the IAEA code of practice (TRS-277) was published in 1987 has explained our knowledge on perturbation and other correction factors in ionization chamber, and also constructional details of these chambers have been shown to be important. Different countries have published, or are in the process of publishing, dosimetry recommendations which include specific procedures for the use of plan parallel ionization chambers. An international working group was formed under the auspieces of the IAEA, first to review the status and the actual validity of the code of practice and second to develop an international code of practice of the use of plane parallel ionization chambers in high energy electron and photon beams used in radiotherapy. This document fulfills the second taste. 153 refs, 21 figs, 18 tabs

  6. A proposed scalable parallel open architecture data acquisition system for low to high rate experiments, test beams and all SSC detectors

    International Nuclear Information System (INIS)

    Barsotti, E.; Booth, A.; Bowden, M.; Swoboda, C.; Lockyer, N.; Vanberg, R.

    1990-01-01

    A new era of high-energy physics research is beginning requiring accelerators with much higher luminosities and interaction rates in order to discover new elementary particles. As a consequence, both orders of magnitude higher data rates from the detector and online processing power, well beyond the capabilities of current high energy physics data acquisition systems, are required. This paper describes a proposed new data acquisition system architecture which draws heavily from the communications industry, is totally parallel (i.e., without any bottlenecks), is capable of data rates of hundreds of Gigabytes per second from the detector and into an array of online processors (i.e., processor farm), and uses an open systems architecture to guarantee compatibility with future commercially available online processor farms. The main features of the proposed Scalable Parallel Open Architecture data acquisition system are standard interface ICs to detector subsystems wherever possible, fiber optic digital data transmission from the near-detector electronics, a self-routing parallel event builder, and the use of industry-supported and high-level language programmable processors in the proposed BCD system for both triggers and online filters. A brief status report of an ongoing project at Fermilab to build a prototype of the proposed data acquisition system architecture is given in the paper. The major component of the system, a self-routing parallel event builder, is described in detail

  7. Highly Parallel Computing Architectures by using Arrays of Quantum-dot Cellular Automata (QCA): Opportunities, Challenges, and Recent Results

    Science.gov (United States)

    Fijany, Amir; Toomarian, Benny N.

    2000-01-01

    -based architectures for highly parallel and systolic computation of signal/image processing applications, such as FFT and Wavelet and Wlash-Hadamard Transforms.

  8. Physical and electrical bandwidths of integrated photodiodes in standard CMOS technology

    NARCIS (Netherlands)

    Radovanovic, S.; Annema, Anne J.; Nauta, Bram

    2003-01-01

    The influence of different geometries (layouts) and structures of high-speed photodiodes in fully standard 0.18 μm CMOS technology on their intrinsic (physical) and electrical bandwidths is analyzed. Three photodiode structures are studied: nwell/p-substrate, p+/nwell/p-substrate and p+/nwell. The

  9. High performance computing of density matrix renormalization group method for 2-dimensional model. Parallelization strategy toward peta computing

    International Nuclear Information System (INIS)

    Yamada, Susumu; Igarashi, Ryo; Machida, Masahiko; Imamura, Toshiyuki; Okumura, Masahiko; Onishi, Hiroaki

    2010-01-01

    We parallelize the density matrix renormalization group (DMRG) method, which is a ground-state solver for one-dimensional quantum lattice systems. The parallelization allows us to extend the applicable range of the DMRG to n-leg ladders i.e., quasi two-dimension cases. Such an extension is regarded to bring about several breakthroughs in e.g., quantum-physics, chemistry, and nano-engineering. However, the straightforward parallelization requires all-to-all communications between all processes which are unsuitable for multi-core systems, which is a mainstream of current parallel computers. Therefore, we optimize the all-to-all communications by the following two steps. The first one is the elimination of the communications between all processes by only rearranging data distribution with the communication data amount kept. The second one is the avoidance of the communication conflict by rescheduling the calculation and the communication. We evaluate the performance of the DMRG method on multi-core supercomputers and confirm that our two-steps tuning is quite effective. (author)

  10. Ultra-high-speed all-channel serial-to-parallel conversion based on complete optical fourier transformation

    DEFF Research Database (Denmark)

    Guan, Pengyu; Røge, Kasper Meldgaard; Morioka, Toshio

    2016-01-01

    We propose a serial-to-parallel conversion scheme based on complete OFT, allowing simultaneous conversion of all channels. We demonstrate all 32-channel simultaneous OTDM to WDM conversion of 320-Gbit/s DPSK and of 640-Gbit/s DQPSK signal, respectively....

  11. High performance shallow water kernels for parallel overland flow simulations based on FullSWOF2D

    KAUST Repository

    Wittmann, Roland; Bungartz, Hans-Joachim; Neumann, Philipp

    2017-01-01

    -by-step transformation of the second order finite volume scheme in FullSWOF2D towards MPI parallelization. Second, the computational kernels are optimized by the use of templates and a portable vectorization approach. We discuss the load imbalance of the flux computation

  12. Parallel Lines

    Directory of Open Access Journals (Sweden)

    James G. Worner

    2017-05-01

    Full Text Available James Worner is an Australian-based writer and scholar currently pursuing a PhD at the University of Technology Sydney. His research seeks to expose masculinities lost in the shadow of Australia’s Anzac hegemony while exploring new opportunities for contemporary historiography. He is the recipient of the Doctoral Scholarship in Historical Consciousness at the university’s Australian Centre of Public History and will be hosted by the University of Bologna during 2017 on a doctoral research writing scholarship.   ‘Parallel Lines’ is one of a collection of stories, The Shapes of Us, exploring liminal spaces of modern life: class, gender, sexuality, race, religion and education. It looks at lives, like lines, that do not meet but which travel in proximity, simultaneously attracted and repelled. James’ short stories have been published in various journals and anthologies.

  13. Bandwidth auction for SVC streaming in dynamic multi-overlay

    Science.gov (United States)

    Xiong, Yanting; Zou, Junni; Xiong, Hongkai

    2010-07-01

    In this paper, we study the optimal bandwidth allocation for scalable video coding (SVC) streaming in multiple overlays. We model the whole bandwidth request and distribution process as a set of decentralized auction games between the competing peers. For the upstream peer, a bandwidth allocation mechanism is introduced to maximize the aggregate revenue. For the downstream peer, a dynamic bidding strategy is proposed. It achieves maximum utility and efficient resource usage by collaborating with a content-aware layer dropping/adding strategy. Also, the convergence of the proposed auction games is theoretically proved. Experimental results show that the auction strategies can adapt to dynamic join of competing peers and video layers.

  14. 3600 digital phase detector with 100-kHz bandwidth

    International Nuclear Information System (INIS)

    Reid, D.W.; Riggin, D.; Fazio, M.V.; Biddle, R.S.; Patton, R.D.; Jackson, H.A.

    1981-01-01

    The general availability of digital circuit components with propagation delay times of a few nanoseconds makes a digital phase detector with good bandwidth feasible. Such a circuit has a distinct advantage over its analog counterpart because of its linearity over wide range of phase shift. A phase detector that is being built at Los Alamos National Laboratory for the Fusion Materials Irradiation Test (FMIT) project is described. The specifications are 100-kHz bandwidth, linearity of +- 1 0 over +- 180 0 of phase shift, and 0.66 0 resolution. To date, the circuit has achieved the bandwidth and resolution. The linearity is approximately +- 3 0 over +- 180 0 phase shift

  15. Energy efficiency in elastic-bandwidth optical networks

    DEFF Research Database (Denmark)

    Vizcaino, Jorge Lopez; Ye, Yabin; Tafur Monroy, Idelfonso

    2011-01-01

    of elastic bandwidth allocation, opens new horizons in the operation of optical networks. In this paper, we compare the network planning problem in an elastic bandwidth CO-OFDM-based network and a fixed-grid WDM network. We highlight the benefits that bandwidth elasticity and the selection of different......The forecasted growth in the Internet traffic has made the operators and industry to be concerned about the power consumption of the networks, and to become interested in alternatives to plan and operate the networks in a more energy efficient manner. The introduction of OFDM, and its property...

  16. Impact of crystal orientation on the modulation bandwidth of InGaN/GaN light-emitting diodes

    Science.gov (United States)

    Monavarian, M.; Rashidi, A.; Aragon, A. A.; Oh, S. H.; Rishinaramangalam, A. K.; DenBaars, S. P.; Feezell, D.

    2018-01-01

    High-speed InGaN/GaN blue light-emitting diodes (LEDs) are needed for future gigabit-per-second visible-light communication systems. Large LED modulation bandwidths are typically achieved at high current densities, with reports close to 1 GHz bandwidth at current densities ranging from 5 to 10 kA/cm2. However, the internal quantum efficiency (IQE) of InGaN/GaN LEDs is quite low at high current densities due to the well-known efficiency droop phenomenon. Here, we show experimentally that nonpolar and semipolar orientations of GaN enable higher modulation bandwidths at low current densities where the IQE is expected to be higher and power dissipation is lower. We experimentally compare the modulation bandwidth vs. current density for LEDs on nonpolar (10 1 ¯ 0 ), semipolar (20 2 ¯ 1 ¯) , and polar (" separators="|0001 ) orientations. In agreement with wavefunction overlap considerations, the experimental results indicate a higher modulation bandwidth for the nonpolar and semipolar LEDs, especially at relatively low current densities. At 500 A/cm2, the nonpolar LED has a 3 dB bandwidth of ˜1 GHz, while the semipolar and polar LEDs exhibit bandwidths of 260 MHz and 75 MHz, respectively. A lower carrier density for a given current density is extracted from the RF measurements for the nonpolar and semipolar LEDs, consistent with the higher wavefunction overlaps in these orientations. At large current densities, the bandwidth of the polar LED approaches that of the nonpolar and semipolar LEDs due to coulomb screening of the polarization field. The results support using nonpolar and semipolar orientations to achieve high-speed LEDs at low current densities.

  17. Apparatus and method for increasing the bandwidth of a laser beam

    Science.gov (United States)

    Wilcox, Russell B.

    1992-01-01

    A method and apparatus using sinusoidal cross-phase modulation, provides a laser pulse having a very broad bandwidth while substantially retaining the input laser's temporal shape. The modulator may be used in a master oscillator system for a laser having a master oscillator-power amplifier (MOPA) configration. The modulator utilizes a first laser providing an output wavelength .lambda. and a second laser providing an output wavelength shifted by a small amount to .lambda.+.DELTA..lambda.. Each beam has a single, linear polarization. Each beam is coupled into a length of polarization-preserving optical fiber. The first laser beam is coupled into the optical fiber with the beam's polarization aligned with the fiber's main axis, and the second beam is coupled into the fiber with its polarization rotated from the main axis by a predetermined angle. Within the fiber, the main axis' polarization defines an interference beam and the orthogonal axis' polarization defines a signal beam. In the interference beam, the first laser beam and the parallel polarized vector component of the other beam interfere to create areas of high and low intensity, which modulates the signal beam by cross phase modulation. Upon exit from the optical fiber, the beams are coupled out and the modulated signal beam is separated out by a polarization selector. The signal beam can be applied to coherence reducing systems to provide an output that is temporally and spatially incoherent. The U.S. Government has rights in this invention pursuant to Contract No. W7405-ENG-48 between the U.S. Department of Energy and the University of California for the operation of Lawrence Livermore National Laboratory.

  18. High-Performance Control of Paralleled Three-Phase Inverters for Residential Microgrid Architectures Based on Online Uninterruptable Power Systems

    DEFF Research Database (Denmark)

    Zhang, Chi; Guerrero, Josep M.; Vasquez, Juan Carlos

    2015-01-01

    In this paper, a control strategy for the parallel operation of three-phase inverters forming an online uninterruptible power system (UPS) is presented. The UPS system consists of a cluster of paralleled inverters with LC filters directly connected to an AC critical bus and an AC/DC forming a DC...... bus. The proposed control scheme is performed on two layers: (i) a local layer that contains a “reactive power vs phase” in order to synchronize the phase angle of each inverter and a virtual resistance loop that guarantees equal power sharing among inverters; (ii) a central controller that guarantees...... synchronization with an external real/fictitious utility, and critical bus voltage restoration. Constant transient and steady-state frequency, active, reactive and harmonic power sharing, and global phase-locked loop resynchronization capability are achieved. Detailed system topology and control architecture...

  19. High-throughput fabrication of micrometer-sized compound parabolic mirror arrays by using parallel laser direct-write processing

    International Nuclear Information System (INIS)

    Yan, Wensheng; Gu, Min; Cumming, Benjamin P

    2015-01-01

    Micrometer-sized parabolic mirror arrays have significant applications in both light emitting diodes and solar cells. However, low fabrication throughput has been identified as major obstacle for the mirror arrays towards large-scale applications due to the serial nature of the conventional method. Here, the mirror arrays are fabricated by using a parallel laser direct-write processing, which addresses this barrier. In addition, it is demonstrated that the parallel writing is able to fabricate complex arrays besides simple arrays and thus offers wider applications. Optical measurements show that each single mirror confines the full-width at half-maximum value to as small as 17.8 μm at the height of 150 μm whilst providing a transmittance of up to 68.3% at a wavelength of 633 nm in good agreement with the calculation values. (paper)

  20. Parallel state transfer and efficient quantum routing on quantum networks.

    Science.gov (United States)

    Chudzicki, Christopher; Strauch, Frederick W

    2010-12-31

    We study the routing of quantum information in parallel on multidimensional networks of tunable qubits and oscillators. These theoretical models are inspired by recent experiments in superconducting circuits. We show that perfect parallel state transfer is possible for certain networks of harmonic oscillator modes. We extend this to the distribution of entanglement between every pair of nodes in the network, finding that the routing efficiency of hypercube networks is optimal and robust in the presence of dissipation and finite bandwidth.

  1. Fast volume reconstruction in positron emission tomography: Implementation of four algorithms on a high-performance scalable parallel platform

    International Nuclear Information System (INIS)

    Egger, M.L.; Scheurer, A.H.; Joseph, C.

    1996-01-01

    The issue of long reconstruction times in PET has been addressed from several points of view, resulting in an affordable dedicated system capable of handling routine 3D reconstruction in a few minutes per frame: on the hardware side using fast processors and a parallel architecture, and on the software side, using efficient implementations of computationally less intensive algorithms. Execution times obtained for the PRT-1 data set on a parallel system of five hybrid nodes, each combining an Alpha processor for computation and a transputer for communication, are the following (256 sinograms of 96 views by 128 radial samples): Ramp algorithm 56 s, Favor 81 s and reprojection algorithm of Kinahan and Rogers 187 s. The implementation of fast rebinning algorithms has shown our hardware platform to become communications-limited; they execute faster on a conventional single-processor Alpha workstation: single-slice rebinning 7 s, Fourier rebinning 22 s, 2D filtered backprojection 5 s. The scalability of the system has been demonstrated, and a saturation effect at network sizes above ten nodes has become visible; new T9000-based products lifting most of the constraints on network topology and link throughput are expected to result in improved parallel efficiency and scalability properties

  2. Bandwidth Estimation in Wireless Lans for Multimedia Streaming Services

    Directory of Open Access Journals (Sweden)

    Heung Ki Lee

    2007-01-01

    Full Text Available The popularity of multimedia streaming services via wireless networks presents major challenges in the management of network bandwidth. One challenge is to quickly and precisely estimate the available bandwidth for the decision of streaming rates of layered and scalable multimedia services. Previous studies based on wired networks are too burdensome to be applied to multimedia applications in wireless networks. In this paper, a new method, IdleGap, is suggested to estimate the available bandwidth of a wireless LAN based on the information from a low layer in the protocol stack. We use a network simulation tool, NS-2, to evaluate our new method with various ranges of cross-traffic and observation times. Our simulation results show that IdleGap accurately estimates the available bandwidth for all ranges of cross-traffic (100 Kbps ∼ 1 Mbps with a very short observation time of 10 seconds.

  3. Composeable Chat over Low-Bandwidth Intermittent Communication Links

    National Research Council Canada - National Science Library

    Wilcox, D. R

    2007-01-01

    Intermittent low-bandwidth communication environments, such as those encountered in U.S. Navy tactical radio and satellite links, have special requirements that do not pertain to commercial applications...

  4. Bandwidth allocation and pricing problem for a duopoly market

    Directory of Open Access Journals (Sweden)

    You Peng-Sheng

    2011-01-01

    Full Text Available This research discusses the Internet service provider (ISP bandwidth allocation and pricing problems for a duopoly bandwidth market with two competitive ISPs. According to the contracts between Internet subscribers and ISPs, Internet subscribers can enjoy their services up to their contracted bandwidth limits. However, in reality, many subscribers may experience the facts that their on-line requests are denied or their connection speeds are far below their contracted speed limits. One of the reasons is that ISPs accept too many subscribers as their subscribers. To avoid this problem, ISPs can set limits for their subscribers to enhance their service qualities. This paper develops constrained nonlinear programming to deal with this problem for two competitive ISPs. The condition for reaching the equilibrium between the two competitive firms is derived. The market equilibrium price and bandwidth resource allocations are derived as closed form solutions.

  5. modeling the effect of bandwidth allocation on network performance

    African Journals Online (AJOL)

    Using MATLAB, simulations were then .... of the network resource. Network bandwidth design, simulation, and management ... encoder processes longer signal data blocks, which entails longer ... c is the modulated signal carrier. However, the ...

  6. Bandwidth-dependent transformation of noise data f

    OpenAIRE

    P. Bormann;  

    1998-01-01

    Additional keywords: bandwidth dependence amplitudes, Dynamikbereich, Frequenzband, relative Bandbreite, spektrale Leistungsdichte der Bodenunruhe, Darstellungen der Bodenunruhespektren in verschiedenen kinematischen Einheiten, Transformation kinematischer Einheiten, Transformation von Spektren in Amplituden der Bodenbewegung, Abhaengigkeit der Amplituden von der Bandbreite

  7. High level trigger system for the ALICE experiment

    International Nuclear Information System (INIS)

    Frankenfeld, U.; Roehrich, D.; Ullaland, K.; Vestabo, A.; Helstrup, H.; Lien, J.; Lindenstruth, V.; Schulz, M.; Steinbeck, T.; Wiebalck, A.; Skaali, B.

    2001-01-01

    The ALICE experiment at the Large Hadron Collider (LHC) at CERN will detect up to 20,000 particles in a single Pb-Pb event resulting in a data rate of ∼75 MByte/event. The event rate is limited by the bandwidth of the data storage system. Higher rates are possible by selecting interesting events and subevents (High Level trigger) or compressing the data efficiently with modeling techniques. Both require a fast parallel pattern recognition. One possible solution to process the detector data at such rates is a farm of clustered SMP nodes, based on off-the-shelf PCs, and connected by a high bandwidth, low latency network

  8. GPU-based parallel algorithm for blind image restoration using midfrequency-based methods

    Science.gov (United States)

    Xie, Lang; Luo, Yi-han; Bao, Qi-liang

    2013-08-01

    GPU-based general-purpose computing is a new branch of modern parallel computing, so the study of parallel algorithms specially designed for GPU hardware architecture is of great significance. In order to solve the problem of high computational complexity and poor real-time performance in blind image restoration, the midfrequency-based algorithm for blind image restoration was analyzed and improved in this paper. Furthermore, a midfrequency-based filtering method is also used to restore the image hardly with any recursion or iteration. Combining the algorithm with data intensiveness, data parallel computing and GPU execution model of single instruction and multiple threads, a new parallel midfrequency-based algorithm for blind image restoration is proposed in this paper, which is suitable for stream computing of GPU. In this algorithm, the GPU is utilized to accelerate the estimation of class-G point spread functions and midfrequency-based filtering. Aiming at better management of the GPU threads, the threads in a grid are scheduled according to the decomposition of the filtering data in frequency domain after the optimization of data access and the communication between the host and the device. The kernel parallelism structure is determined by the decomposition of the filtering data to ensure the transmission rate to get around the memory bandwidth limitation. The results show that, with the new algorithm, the operational speed is significantly increased and the real-time performance of image restoration is effectively improved, especially for high-resolution images.

  9. A high performance image processing platform based on CPU-GPU heterogeneous cluster with parallel image reconstroctions for micro-CT

    International Nuclear Information System (INIS)

    Ding Yu; Qi Yujin; Zhang Xuezhu; Zhao Cuilan

    2011-01-01

    In this paper, we report the development of a high-performance image processing platform, which is based on CPU-GPU heterogeneous cluster. Currently, it consists of a Dell Precision T7500 and HP XW8600 workstations with parallel programming and runtime environment, using the message-passing interface (MPI) and CUDA (Compute Unified Device Architecture). We succeeded in developing parallel image processing techniques for 3D image reconstruction of X-ray micro-CT imaging. The results show that a GPU provides a computing efficiency of about 194 times faster than a single CPU, and the CPU-GPU clusters provides a computing efficiency of about 46 times faster than the CPU clusters. These meet the requirements of rapid 3D image reconstruction and real time image display. In conclusion, the use of CPU-GPU heterogeneous cluster is an effective way to build high-performance image processing platform. (authors)

  10. TPROXY dan FILTERING SEBAGAI METODE OPTIMASI PEMAKAIAN BANDWIDTH INTERNET

    Directory of Open Access Journals (Sweden)

    Sutiyo Sutiyo

    2015-04-01

    Full Text Available Until now the use of the internet disuatu agencies viewed from the initial planning, use and care, even long-term planning is still not optimal. The main factor lies in the existing human resources, especially in IT personnel and policy makers who do not understand or do not even know at all how your use of the Internet well, optimal, efficient, particularly associated with the consumption of Internet bandwidth. Internet bandwidth capacity greatly affect the speed of web access or other Internet applications. So we need a plan and maintance necessary to obtain good Internet bandwidth consumption efficiency and guaranteed QoS, such as by utilizing Tproxy and filtering methods. TProxy is a development of which has been patched Squid, a proxy to be able to pass traffic without NAT (Network Access Translation. Fitering a firewall system which is used for filtering data packets that do not want filtered dikendaki or akhirmya able to minimize traffic on bandwidth usage. Tproxy and filtering runs on the Linux platform. Linux distributions are often used to Tproxy is a variant Debian, Centos and then to use Mikrotik Filtering. At the end of each request or query from the client or the response of the proxy server does not have meaningful constraints, the bandwidth between the client and the proxy server does not happen limitation, bandwidth capable of running close to capacity including 10 Mbps Ethernet, 100 Mbps, and even a GPS (full speed.

  11. GPU-based Parallel Application Design for Emerging Mobile Devices

    Science.gov (United States)

    Gupta, Kshitij

    A revolution is underway in the computing world that is causing a fundamental paradigm shift in device capabilities and form-factor, with a move from well-established legacy desktop/laptop computers to mobile devices in varying sizes and shapes. Amongst all the tasks these devices must support, graphics has emerged as the 'killer app' for providing a fluid user interface and high-fidelity game rendering, effectively making the graphics processor (GPU) one of the key components in (present and future) mobile systems. By utilizing the GPU as a general-purpose parallel processor, this dissertation explores the GPU computing design space from an applications standpoint, in the mobile context, by focusing on key challenges presented by these devices---limited compute, memory bandwidth, and stringent power consumption requirements---while improving the overall application efficiency of the increasingly important speech recognition workload for mobile user interaction. We broadly partition trends in GPU computing into four major categories. We analyze hardware and programming model limitations in current-generation GPUs and detail an alternate programming style called Persistent Threads, identify four use case patterns, and propose minimal modifications that would be required for extending native support. We show how by manually extracting data locality and altering the speech recognition pipeline, we are able to achieve significant savings in memory bandwidth while simultaneously reducing the compute burden on GPU-like parallel processors. As we foresee GPU computing to evolve from its current 'co-processor' model into an independent 'applications processor' that is capable of executing complex work independently, we create an alternate application framework that enables the GPU to handle all control-flow dependencies autonomously at run-time while minimizing host involvement to just issuing commands, that facilitates an efficient application implementation. Finally, as

  12. A scalable parallel open architecture data acquisition system for low to high rate experiments, test beams and all SSC [Superconducting Super Collider] detectors

    International Nuclear Information System (INIS)

    Barsotti, E.; Booth, A.; Bowden, M.; Swoboda, C.; Lockyer, N.; VanBerg, R.

    1989-12-01

    A new era of high-energy physics research is beginning requiring accelerators with much higher luminosities and interaction rates in order to discover new elementary particles. As a consequences, both orders of magnitude higher data rates from the detector and online processing power, well beyond the capabilities of current high energy physics data acquisition systems, are required. This paper describes a new data acquisition system architecture which draws heavily from the communications industry, is totally parallel (i.e., without any bottlenecks), is capable of data rates of hundreds of GigaBytes per second from the detector and into an array of online processors (i.e., processor farm), and uses an open systems architecture to guarantee compatibility with future commercially available online processor farms. The main features of the system architecture are standard interface ICs to detector subsystems wherever possible, fiber optic digital data transmission from the near-detector electronics, a self-routing parallel event builder, and the use of industry-supported and high-level language programmable processors in the proposed BCD system for both triggers and online filters. A brief status report of an ongoing project at Fermilab to build the self-routing parallel event builder will also be given in the paper. 3 figs., 1 tab

  13. Optical slotted circuit switched network: a bandwidth efficient alternative to wavelength-routed network

    Science.gov (United States)

    Li, Yan; Collier, Martin

    2007-11-01

    Wavelength-routed networks have received enormous attention due to the fact that they are relatively simple to implement and implicitly offer Quality of Service (QoS) guarantees. However, they suffer from a bandwidth inefficiency problem and require complex Routing and Wavelength Assignment (RWA). Most attempts to address the above issues exploit the joint use of WDM and TDM technologies. The resultant TDM-based wavelength-routed networks partition the wavelength bandwidth into fixed-length time slots organized as a fixed-length frame. Multiple connections can thus time-share a wavelength and the grooming of their traffic leads to better bandwidth utilization. The capability of switching in both wavelength and time domains in such networks also mitigates the RWA problem. However, TMD-based wavelength-routed networks work in synchronous mode and strict synchronization among all network nodes is required. Global synchronization for all-optical networks which operate at extremely high speed is technically challenging, and deploying an optical synchronizer for each wavelength involves considerable cost. An Optical Slotted Circuit Switching (OSCS) architecture is proposed in this paper. In an OSCS network, slotted circuits are created to better utilize the wavelength bandwidth than in classic wavelength-routed networks. The operation of the protocol is such as to avoid the need for global synchronization required by TDM-based wavelength-routed networks.

  14. Bandwidth Dependence of Laser Plasma Instabilities Driven by the Nike KrF Laser

    Science.gov (United States)

    Weaver, J. L.; Oh, J.; Seely, J.; Kehne, D.; Brown, C. M.; Obenschain, S.; Serlin, V.; Schmitt, A. J.; Phillips, L.; Lehmberg, R. H.; McLean, E.; Manka, C.; Feldman, U.

    2011-10-01

    The Nike krypton-fluoride (KrF) laser at the Naval Research Laboratory operates in the deep UV (248 nm) and employs beam smoothing by induced spatial incoherence (ISI). In the first ISI studies at longer wavelengths (1054 nm and 527 nm) [Obenschain, PRL 62, 768(1989);Mostovych, PRL, 59, 1193(1987); Peyser, Phys. Fluids B 3, 1479(1991)], stimulated Raman scattering, stimulated Brillouin scattering, and the two plasmon decay instability were reduced when wide bandwidth ISI (δν / ν ~ 0.03-0.19%) pulses irradiated targets at moderate to high intensities (1014-1015W/cm2) . Recent Nike work showed that the threshold for quarter critical instabilities increased with the expected wavelength scaling, without accounting for the large bandwidth (δν ~ 1-3 THz). New experiments will compare laser plasma instabilities (LPI) driven by narrower bandwidth pulses to those observed with the standard operation. The bandwidth of KrF lasers can be reduced by adding narrow filters (etalons or gratings) in the initial stages of the laser. This talk will discuss the method used to narrow the output spectrum of Nike, the laser performance for this new operating mode, and target observations of LPI in planar CH targets. Work supported by DoE/NNSA.

  15. Design Analysis and Dynamic Modeling of a High-Speed 3T1R Pick-and-Place Parallel Robot

    DEFF Research Database (Denmark)

    Wu, Guanglei; Bai, Shaoping; Hjørnet, Preben

    2015-01-01

    This paper introduces a four degree-of-freedom parallel robot producing three translation and one rotation (Schönflies motion). This robot can generate a rectangular workspace that is close to the applicable work envelope and suitable for pick-and-place operations. The kinematics of the robot...... is studied to analyze the workspace and the isocontours of the local dexterity over the representative regular workspace are visualized. The simplified dynamics is modeled and compared with Adams model to show its effectiveness....

  16. Attachment of lead wires to thin film thermocouples mounted on high temperature materials using the parallel gap welding process

    Science.gov (United States)

    Holanda, Raymond; Kim, Walter S.; Pencil, Eric; Groth, Mary; Danzey, Gerald A.

    1990-01-01

    Parallel gap resistance welding was used to attach lead wires to sputtered thin film sensors. Ranges of optimum welding parameters to produce an acceptable weld were determined. The thin film sensors were Pt13Rh/Pt thermocouples; they were mounted on substrates of MCrAlY-coated superalloys, aluminum oxide, silicon carbide and silicon nitride. The entire sensor system is designed to be used on aircraft engine parts. These sensor systems, including the thin-film-to-lead-wire connectors, were tested to 1000 C.

  17. Orientation masking and cross-orientation suppression (XOS): implications for estimates of filter bandwidth.

    Science.gov (United States)

    Meese, Tim S; Holmes, David J

    2010-10-01

    Most contemporary models of spatial vision include a cross-oriented route to suppression (masking from a broadly tuned inhibitory pool), which is most potent at low spatial and high temporal frequencies (T. S. Meese & D. J. Holmes, 2007). The influence of this pathway can elevate orientation-masking functions without exciting the target mechanism, and because early psychophysical estimates of filter bandwidth did not accommodate this, it is likely that they have been overestimated for this corner of stimulus space. Here we show that a transient 40% contrast mask causes substantial binocular threshold elevation for a transient vertical target, and this declines from a mask orientation of 0° to about 40° (indicating tuning), and then more gently to 90°, where it remains at a factor of ∼4. We also confirm that cross-orientation masking is diminished or abolished at high spatial frequencies and for sustained temporal modulation. We fitted a simple model of pedestal masking and cross-orientation suppression (XOS) to our data and those of G. C. Phillips and H. R. Wilson (1984) and found the dependency of orientation bandwidth on spatial frequency to be much less than previously supposed. An extension of our linear spatial pooling model of contrast gain control and dilution masking (T. S. Meese & R. J. Summers, 2007) is also shown to be consistent with our results using filter bandwidths of ±20°. Both models include tightly and broadly tuned components of divisive suppression. More generally, because XOS and/or dilution masking can affect the shape of orientation-masking curves, we caution that variations in bandwidth estimates might reflect variations in processes that have nothing to do with filter bandwidth.

  18. High figure of merit ultra-compact 3-channel parallel-connected photonic crystal mini-hexagonal-H1 defect microcavity sensor array

    Science.gov (United States)

    Wang, Chunhong; Sun, Fujun; Fu, Zhongyuan; Ding, Zhaoxiang; Wang, Chao; Zhou, Jian; Wang, Jiawen; Tian, Huiping

    2017-08-01

    In this paper, a photonic crystal (PhC) butt-coupled mini-hexagonal-H1 defect (MHHD) microcavity sensor is proposed. The MHHD microcavity is designed by introducing six mini-holes into the initial H1 defect region. Further, based on a well-designed 1 ×3 PhC Beam Splitter and three optimal MHHD microcavity sensors with different lattice constants (a), a 3-channel parallel-connected PhC sensor array on monolithic silicon on insulator (SOI) is proposed. Finite-difference time-domain (FDTD) simulations method is performed to demonstrate the high performance of our structures. As statistics show, the quality factor (Q) of our optimal MHHD microcavity attains higher than 7×104, while the sensitivity (S) reaches up to 233 nm/RIU(RIU = refractive index unit). Thus, the figure of merit (FOM) >104 of the sensor is obtained, which is enhanced by two orders of magnitude compared to the previous butt-coupled sensors [1-4]. As for the 3-channel parallel-connected PhC MHHD microcavity sensor array, the FOMs of three independent MHHD microcavity sensors are 8071, 8250 and 8250, respectively. In addition, the total footprint of the proposed 3-channel parallel-connected PhC sensor array is ultra-compactness of 12.5 μm ×31 μm (width × length). Therefore, the proposed high FOM sensor array is an ideal platform for realizing ultra-compact highly parallel refractive index (RI) sensing.

  19. An efficient implementation of 3D high-resolution imaging for large-scale seismic data with GPU/CPU heterogeneous parallel computing

    Science.gov (United States)

    Xu, Jincheng; Liu, Wei; Wang, Jin; Liu, Linong; Zhang, Jianfeng

    2018-02-01

    De-absorption pre-stack time migration (QPSTM) compensates for the absorption and dispersion of seismic waves by introducing an effective Q parameter, thereby making it an effective tool for 3D, high-resolution imaging of seismic data. Although the optimal aperture obtained via stationary-phase migration reduces the computational cost of 3D QPSTM and yields 3D stationary-phase QPSTM, the associated computational efficiency is still the main problem in the processing of 3D, high-resolution images for real large-scale seismic data. In the current paper, we proposed a division method for large-scale, 3D seismic data to optimize the performance of stationary-phase QPSTM on clusters of graphics processing units (GPU). Then, we designed an imaging point parallel strategy to achieve an optimal parallel computing performance. Afterward, we adopted an asynchronous double buffering scheme for multi-stream to perform the GPU/CPU parallel computing. Moreover, several key optimization strategies of computation and storage based on the compute unified device architecture (CUDA) were adopted to accelerate the 3D stationary-phase QPSTM algorithm. Compared with the initial GPU code, the implementation of the key optimization steps, including thread optimization, shared memory optimization, register optimization and special function units (SFU), greatly improved the efficiency. A numerical example employing real large-scale, 3D seismic data showed that our scheme is nearly 80 times faster than the CPU-QPSTM algorithm. Our GPU/CPU heterogeneous parallel computing framework significant reduces the computational cost and facilitates 3D high-resolution imaging for large-scale seismic data.

  20. Binary zone-plate array for a parallel joint transform correlator applied to face recognition.

    Science.gov (United States)

    Kodate, K; Hashimoto, A; Thapliya, R

    1999-05-10

    Taking advantage of small aberrations, high efficiency, and compactness, we developed a new, to our knowledge, design procedure for a binary zone-plate array (BZPA) and applied it to a parallel joint transform correlator for the recognition of the human face. Pairs of reference and unknown images of faces are displayed on a liquid-crystal spatial light modulator (SLM), Fourier transformed by the BZPA, intensity recorded on an optically addressable SLM, and inversely Fourier transformed to obtain correlation signals. Consideration of the bandwidth allows the relations among the channel number, the numerical aperture of the zone plates, and the pattern size to be determined. Experimentally a five-channel parallel correlator was implemented and tested successfully with a 100-person database. The design and the fabrication of a 20-channel BZPA for phonetic character recognition are also included.