Sample records for multi level inverter

  1. Reliability comparison of multi-level inverters for motor drive

    Microsoft Academic Search

    Liang Zhou; Keyue Smedley

    2009-01-01

    Due to the unique interconnecting nature of hexagram inverter, it can tolerate one leg failure without adding major power component. In the event of one leg failure, the whole power module is disabled and new control method will be initiated for hexagram inverter. Another widely used multi-level topology is Cascaded H-bridge Inverter, which proves to have extremely high reliability when

  2. Inverter Minimization in Multi-Level Logic Networks Department of ECE

    E-print Network

    Bryant, Randal E.

    Inverter Minimization in Multi-Level Logic Networks Alok Jain Department of ECE Carnegie Mellon Pittsburgh, PA 15213 Abstract In this paper, we look at the problem of inverter minimization in multi approach takes a more global view and maps the problem of inverter minimization into a problem of removing

  3. A novel structure of multi-level high voltage source inverter

    Microsoft Academic Search

    Young-Seek Kim; Beom-Seok Seo; Dong-Seok Hyun

    1993-01-01

    This paper deals with a new multi-level high voltage source inverter with GTO thyristors. A multi-level approach seems to be best suited for implementing a high voltage conversion system because it leads to harmonic reduction and safely deals with a high power conversion system independent of the dynamic switching characteristics of each power semiconductor device. However, a conventional multi-level inverter

  4. Performance Evaluation of a Cascaded H-Bridge Multi Level Inverter Fed BLDC Motor Drive in an Electric Vehicle 

    E-print Network

    Emani, Sriram S.

    2011-08-08

    . The design parameters are meant to meet the requirements of a commercial car. The various advantages of a multi level inverter fed PMSM have been demonstrated and an exhaustive performance evaluation has been done. The investigation is done by testing...

  5. Performance Evaluation of a Cascaded H-Bridge Multi Level Inverter Fed BLDC Motor Drive in an Electric Vehicle

    E-print Network

    Emani, Sriram S.

    2011-08-08

    . The design parameters are meant to meet the requirements of a commercial car. The various advantages of a multi level inverter fed PMSM have been demonstrated and an exhaustive performance evaluation has been done. The investigation is done by testing...

  6. Speed Control of Multi Level Inverter Designed DC Series Motor with Neuro-Fuzzy Controllers

    E-print Network

    MadhusudhanaRao, G

    2009-01-01

    This paper describes the speed control of a DC series motor for an accurate and high-speed performance. A neural network based controlling operation with fuzzy modeling is suggested in this paper. The driver units of these machines are designed with a Multi-level inverter operation and are controlled by a common current control mechanism for an accurate and efficient driving technique for DC series motor. The neuro-fuzzy logic control technique is introduced to eliminate uncertainties in the plant parameters of the DC Series motors, and also considered as potential candidate for different applications to prove adequacy of the proposed control algorithm through simulations. The simulation result with such an approach is made and observed efficient over other controlling technique.

  7. Neutral point control for multi-level inverters: theory, design and operational limitations

    Microsoft Academic Search

    C. Newton; M. Sumner

    1997-01-01

    This paper describes the theory, design, and operation of a neutral point voltage control system for a three level inverter drive system. The paper specifically addresses: (1) the mathematical derivation of the neutral point control principle described, defining the operating limits imposed; (2) design of a closed loop control system; (3) and modifications to the control system to enable operation

  8. A novel SVPWM strategy considering DC-link balancing for a multi-level voltage source inverter

    Microsoft Academic Search

    Yo-Han Lee; Rae-Young Kim; Dong-Seok Hyun

    1999-01-01

    This paper proposes a novel SVPWM (space vector pulse width modulation) strategy for a multi-level voltage source inverter. This strategy is easily implemented as SPWM (sinusoidal pulse width modulation) and has the same DC-link voltage utilization as the general SVPWM scheme. The method to keep the voltage balance of the DC-link is also proposed by the analysis of DC-link voltage

  9. Performance of a High Speed Motor Drive System Using a Novel MultiLevel Inverter Topology

    Microsoft Academic Search

    J. Ewanchuk; J. Salmon; A. Knight

    2008-01-01

    This paper examines the performance of a novel multilevel six-switch three phase inverter drive for low-voltage high speed motor applications. Hard switched voltage source inverter topologies are limited in terms of switching frequency and therefore as the frequency modulation ratio decreases, the resulting increase in harmonic currents may cause excessive rotor heating or lead to larger than desired output reactors

  10. A multi level space phasor based PWM strategy for an open-end winding induction motor drive using two inverters with different DC link voltages

    Microsoft Academic Search

    E. G. Shivakumar; V. T. Somasekhar; K. K. Mohapatra; K. Gopakumar; L. Umanand; S. K. Sinha

    2001-01-01

    An open-end winding induction motor drive fed from two inverters with different DC link voltages is proposed in this paper. A total of 64 voltage space phasor combinations are possible in this scheme as each inverter produces 8 voltage space phasors. The proposed scheme produces voltage space phasor locations more than that of a 3-level inverter. A total of 37

  11. Analysis and Design of a Novel Three-Level LLCC Inverter Supplying an Airborne Piezoelectric

    E-print Network

    Paderborn, Universität

    Analysis and Design of a Novel Three-Level LLCC Inverter Supplying an Airborne Piezoelectric Brake on the investigation of a novel single-phase three-level PWM inverter in the kW power range, feeding a high power multi suit best to the needs of ultrasonic motors has been conducted. A resonant inverter with LLCC

  12. Mono inverter Multi parallel PMSM -Structure and Control strategy

    E-print Network

    Boyer, Edmond

    Mono inverter Multi parallel PMSM - Structure and Control strategy Damien Bidarta , Maria Pietrzak a new and original Mono inverter Multi parallel Permanent Magnet Synchronous Motor (PMSM) system. Experimental results are given for a system with 2 PMSM plugged in parallel. The proposed solution can however

  13. Simplified space vector PWM algorithm for five-level inverter

    NASA Astrophysics Data System (ADS)

    Lalili, D.; Berkouk, E. M.; Boudjema, F.; Lourci, N.; Taleb, T.; Petzold, J.

    2007-12-01

    In this work, we present an algorithm for the space vector pulse width modulation (SVPWM) applied to five-level diode clamped inverter. In this algorithm, the space vector diagram of the five-level inverter is decomposed into six space vector diagrams of three-level inverters. In turn, each of these six space vector diagrams of three-level inverter is decomposed into six space vector diagrams of two-level inverters. This idea allows us to generalize the two-level SVPWM algorithm into the case of five-level inverter.

  14. Multi-star induction motors fed by voltage source inverters

    Microsoft Academic Search

    H. Stemmler; R. Deplazes

    1997-01-01

    This paper deals with the problems of multi-star induction motors fed by voltage source inverters. After an introduction, the structure of this drive system is described using the example of a 3-star motor with three independent 3-phase windings in the stator which are phase shifted mechanically against each other. Based on the transient equations derived, a control structure is proposed.

  15. Novel PWM scheme to control neutral point voltage variation in three-level voltage source inverter

    Microsoft Academic Search

    K. R. M. N. Ratnayake; Y. Murai; T. Watanabe

    1999-01-01

    This paper proposes a simple PWM scheme which alleviates the neutral point voltage fluctuation problem of the three level inverter applications. The new scheme employs modified version of well known multi-level sinusoidal pulse width modulation (SPWM) scheme. This modification shows a great potential of reducing neutral point voltage fluctuation and retained better sinusoidal shape at the output. This method avoids

  16. A study on design of inverter for multi-phase brushless DC ship propulsion motor

    Microsoft Academic Search

    Sun-Jung Park; Jong-Hwan Song; Ho-Yong Choi; Man-Li Lee; Young-Kyung Kong; Jae-Goo Bin

    2010-01-01

    This paper describes inverter for multi-phase brushless DC ship propulsion motor. This inverter has high efficiency and relatively small size. It is separated multi-phase brushless DC motor drive and motor-inverter built-in type. Some inverter modules are damaged, the motor can be limited drive by other living inverters. In order to maintain high efficiency at low speed, same phase coils of

  17. A four level rectifier inverter system for drive applications

    Microsoft Academic Search

    G. Sinha; T.A. Lipo

    1998-01-01

    In a motor drive, the converters must be able to handle bidirectional real power flow. So far, DC voltage balancing has not been satisfactorily discussed for the case when real power is drawn from the inverter. This article addresses the control issues involved in a four-level inverter based AC drive application. The DC capacitor voltages are balanced for both motoring

  18. Five-level GTO inverters for large induction motor drives

    Microsoft Academic Search

    R. W. Menzies; P. Steimer; J. K. Steinke

    1994-01-01

    The development of large induction motor drives with low torque ripple and fast dynamic response for new or retrofit applications has been limited by the device ratings and problems of series connections. This paper investigates the use of a five-level GTO voltage-sourced inverter for large induction motor drives. The advantages of such a drive are that single GTO thyristors may

  19. Development of a compact 750KVA three-phase NPC three-level universal inverter module with specifically designed busbar

    Microsoft Academic Search

    Jun Wang; Binjian Yang; Jing Zhao; Yan Deng; Xiangning He; Xu Zhixin

    2010-01-01

    This paper presents the bus bar design of a 750kVA three-phase Neutral Point Clamped three-level universal inverter module (PEBB) of high power density. ANSOFT Q3D is used in comparative evaluation for three types of multi-layer bus bar structures and a novel low inductive laminated configuration with divided connections is proposed for this inverter modules. Combined with specially arranged snubber capacitors

  20. Topological and Modulation Design of Three-Level Z-Source Inverters

    Microsoft Academic Search

    P. C. Loh; F. Gao; F. Blaabjerg

    2006-01-01

    This paper presents the development of two three-level cascaded Z-source inverters, whose output voltage can be stepped down or up unlike a traditional buck three-level inverter. The proposed inverters are designed using two three-phase voltage-source inverter bridges, supplied by two uniquely designed Z-source impedance networks and cascaded at either their DC sides to form a DC-link-cascaded Z-source inverter or AC

  1. A Five-Level Three-Phase Hybrid Cascade Multilevel Inverter Using a Single DC Source

    E-print Network

    Tolbert, Leon M.

    A Five-Level Three-Phase Hybrid Cascade Multilevel Inverter Using a Single DC Source for a PM with each inverter leg, which use a capacitor as a DC source. It is shown that one can simultaneously to synthesize a desired AC voltage from several levels of DC voltages. Such inverters have been the subject

  2. Topological and Modulation Design of Three-Level Z-Source Inverters

    Microsoft Academic Search

    Poh Chiang Loh; Feng Gao; Frede Blaabjerg

    2008-01-01

    This paper presents the development of two three-level cascaded Z-source inverters, whose output voltage can be stepped down or up unlike a traditional buck three-level inverter. The proposed inverters are designed using two three-phase voltage-source inverter bridges, supplied by two uniquely designed Z-source impedance networks. These three-phase bridges can either be cascaded at their dc sides to form a dc-link-cascaded

  3. 11-level Cascaded H-bridge Grid-tied Inverter Interface with Solar Panels

    E-print Network

    Tolbert, Leon M.

    11-level Cascaded H-bridge Grid-tied Inverter Interface with Solar Panels Faete Filho, Yue Cao multilevel DC-AC grid-tied inverter. Each inverter bridge is connected to a 200 W solar panel. OPAL-RT lab match. A novel SPWM scheme is proposed in this paper to be used with the solar panels that can account

  4. Three Phase Three-Level PWM Switched Voltage Source Inverter With Zero Neutral Point Potential

    Microsoft Academic Search

    Won-Sik Oh; Sang-Kyoo Han; Seong-Wook Choi; Gun-Woo Moon

    2006-01-01

    A new three phase three-level pulsewidth modulation (PWM) switched voltage source inverter with zero neutral point potential is proposed. It consists of three single-phase inverter modules and each module is composed of a switched voltage source and inverter switches. The major advantage is that the peak value of the phase output voltage is twice as high as that of the

  5. Performance Evaluation of Three-Level Z-Source Inverters Under Semiconductor-Failure Conditions

    Microsoft Academic Search

    Feng Gao; Poh Chiang Loh; Frede Blaabjerg; D. Mahinda Vilathgamuwa

    2009-01-01

    This paper evaluates and proposes various compensation methods for three-level Z-source inverters under semiconductor-failure conditions. Unlike the fault-tolerant techniques used in traditional three-level inverters, where either an extra phase-leg or collective switching states are used, the proposed methods for three-level Z-source inverters simply reconfigure their relevant gating signals so as to ride-through the failed semiconductor conditions smoothly without any significant

  6. Multi-level converters for three-phase photovoltaic applications

    E-print Network

    Lehman, Brad

    in Fig. 1. The single DC source input voltage charges the input ca- pacitors. The output voltage is a fraction of the total voltage provided by the DC source. This means that the total power available from interesting extensions of the multi-level single-phase inverter concept to the case of multiple DC source

  7. Megawatt GTO-inverter with three-level PWM control and regenerative snubber circuits

    Microsoft Academic Search

    Joachim Holtz; Samir F. Salama

    1988-01-01

    Regenerative turn-on and turn-of snubbers for a three-level PWM inverter using gate turn-off thyristors (GTOs) are analyzed and discussed. Problems encountered in high-power GTO inverters, namely, trapped energy in the snubbers and switching losses, are discussed. The circuit configuration and operation are described and a comparison with a two-level inverter is made. Experimental results from the operation at reduced voltage

  8. Dual Z-Source Inverter With Three-Level Reduced Common-Mode Switching

    Microsoft Academic Search

    Feng Gao; Poh Chiang Loh; Frede Blaabjerg; D. Mahinda Vilathgamuwa

    2007-01-01

    This paper presents the design of a dual Z-source inverter that can be used with either a single dc source or two isolated dc sources. Unlike traditional inverters, the integration of a properly designed Z-source network and semiconductor switches to the proposed dual inverter allows buck-boost power conversion to be performed over a wide modulation range, with three-level output waveforms

  9. Dual Z-source Inverter with Three-Level Reduced Common Mode Switching

    Microsoft Academic Search

    F. Gao; P. C. Loh; F. Blaabjerg; D. M. Vilathgamuwa

    2006-01-01

    This paper presents the design of a dual Z-source inverter that can be used with either a single dc source or two isolated dc sources. Unlike traditional inverters, the integration of a properly designed Z-source network and semiconductor switches to the proposed dual inverter allows buck-boost power conversion to be performed over a wide modulation range with three-level output waveforms

  10. PWM\\/PDM dual mode controlled soft switching multi resonant high-frequency inverter

    Microsoft Academic Search

    K. Fathy; Y. Miura; K. Yasui; I. Hirota; T. Iwai; H. Omori; Hyun Woo Lee; M. Nakaoka

    2005-01-01

    In this paper, a novel type auxiliary active resonant capacitor snubber assisted zero current soft switching pulse modulation single-ended push pull (SEPP) series load resonant inverter with two auxiliary resonant lossless inductor snubbers is proposed for consumer high-frequency induction heating (IH) appliances. Its operating principle in steady state is described by using each mode equivalent circuits. The new multi resonant

  11. A Multi-feature Based Invertible Authentication Watermarking for JPEG Images

    Microsoft Academic Search

    Ye Deng-pan; Mao Yao-bin; Dai Yue-wei; Wang Zhi-quan

    2004-01-01

    Invertible authentication techniques have been used in some special applications (such as medical or military) where original data can be recovered after authenticated. In this paper, we combine features (relation of coefficients) in DCT domain with content features (edges or texture) of JPEG image into multi-features, which are useful to authenticating images from both spatial and frequency domains. A novel

  12. Space vector pulse width modulation of three-level inverter extending operation into overmodulation region

    Microsoft Academic Search

    Subrata K. Mondal; Bimal K. Bose; Valentin Oleschuk; Joao O. P. Pinto

    2003-01-01

    Multilevel voltage-fed inverters with space vector pulse width modulation have established their importance in high power high performance industrial drive applications. The paper proposes an overmodulation strategy of space vector PWM of a three-level inverter with linear transfer characteristic that easily extends from the undermodulation strategy previously developed by the authors for neural network implementation. The overmodulation strategy is very

  13. Loss balancing in three-level voltage source inverters applying active NPC switches

    Microsoft Academic Search

    T. Bruckner; S. Bemet

    2001-01-01

    This paper investigates the use of active neutral point clamp switches in a three-level NPC voltage source inverter to balance the losses among the semiconductors. Both a control structure and algorithm are proposed which enable a substantially increased output power of the inverter and an improved performance at zero speed

  14. Three-Level Z-Source Inverters Using a Single LC Impedance Network

    Microsoft Academic Search

    Poh Chiang Loh; Sok Wei Lim; Feng Gao; Frede Blaabjerg

    2007-01-01

    Three-level Z-source inverters are recent single-stage topological solutions proposed for buck-boost energy conversion with all favorable advantages of three-level switching retained. Despite their effectiveness in achieving voltage buck-boost conversion, existing three-level Z-source inverters use two LC impedance networks and two isolated dc sources, which can significantly increase the overall system cost and require a more complex modulator for balancing the

  15. Large capacity high performance 3-level GTO inverter system for steel main rolling mill drives

    Microsoft Academic Search

    Hideo Okayama; Ryohei Uchida; Masato Koyama; S. Mizoguchi; Shinzo Tamai; H. Ogawa; T. Fujii; Yasuhito Shimomura

    1996-01-01

    This paper proposes a high performance 10 MVA 3-level GTO inverter system for steel main rolling mill drives, which consists of a three-level power converter, a three-level inverter and two series-connected DC-link capacitors with a neutral point. To realize this system, newly developed 6-inch 6 kV-6 kA GTOs have been applied first in the world. A novel regenerative snubber circuit

  16. Modeling and design of multi-loop closed loop controller for Z-source inverter for Distributed Generation

    Microsoft Academic Search

    C. J. Gajanayake; D. Mahinda Vilathgamuwa; Poh Chiang Loh

    2006-01-01

    This paper presents the modelling and designing of a multi loop controller for Z-source inverters used in distributed generation systems. Z-source inverter is recently proposed converter capable of operating in buck and boost modes. Hence it is more suitable for DG applications over the other alternative converter topologies. When employing the Z-source inverter in DG applications, closed loop controlling is

  17. Performance Evaluation of Switch Devices Equipped in High-Power Three-Level Inverters

    Microsoft Academic Search

    Liqiang Yuan; Zhengming Zhao; Mohamed Eltawil; Rong Yi; Hua Bai

    2007-01-01

    The feature of the integrated gate-commutated thyristors (IGCTs) makes them have excellent performance in high-voltage high-current field. The high integration of drives and devices makes it very convenient to use them. In order to examine the dynamic characters of switch devices in high-power three-level inverter, an experimental test for IGCTs and diodes equipped in inverter is proposed and described in

  18. Investigation of circuit-level oxide degradation and its effect on CMOS inverter operation and MOSFET characteristics

    Microsoft Academic Search

    Betsy J. Cheek; Nate Stutzke; Santosh Kumar; R. Jacob Baker; Amy J. Moll; William B. Knowlton

    2004-01-01

    Circuit-level oxide degradation effects on CMOS inverter circuit operation and individual MOSFET behavior is investigated. Individual PMOSFET and NMOSFET devices are assembled off-wafer in the inverter configuration through a switch matrix. A range of gate oxide degradation mechanisms are induced by applying a ramped voltage stress (RVS) of various magnitudes to the input of the inverter. A novel circuit model

  19. Operational analysis and modulation control of three-level Z-source inverters with enhanced output waveform quality

    Microsoft Academic Search

    Poh Chiang Loh; Feng Gao; Frede Blaabjerg; Sok Wei Lim

    2007-01-01

    Three-level Z-source inverters are recent single-stage topological solutions proposed for buck-boost energy conversion with all favorable advantages of three-level switching retained. Despite their proven buck-boost capability, existing three-level Z-source inverters are either too costly with numerous passive LC elements needed or poor in spectral quality if the \\

  20. Modeling of Busbars in High Power Neutral Point Clamped Three-Level Inverters

    Microsoft Academic Search

    Rong Yi; Zhengming Zhao; Yulin Zhong

    2008-01-01

    The busbars in high power neutral point clamped three-level inverters are modeled using the Maxwell Q3D Extractor software, which is based on the partial element equivalent circuits method. The equivalent circuits of the busbars and devices model are simulated in the electric simulator PSIM to analyze the effects of the parasitic inductance on the switching characteristics of the integrated gate

  1. Effects of Circuit-Level Stress on Inverter Performance and MOSFET Characteristics Nate Stutzke1

    E-print Network

    Baker, R. Jacob

    circuit stages to compensate for a few degraded devices, but increased rise/fall and delay times may cause devices [7], increased rise/fall and delay times may result in potential timing issues in highEffects of Circuit-Level Stress on Inverter Performance and MOSFET Characteristics Nate Stutzke1

  2. DSP based space vector PWM for three-level inverter with DC-link voltage balancing

    Microsoft Academic Search

    Hyo L. Liu; Nam S. Choi; Gyu H. Cho

    1991-01-01

    The authors describe a novel PWM (pulse width modulation) method for a three-level inverter considering the DC link capacitor balancing problem. Each voltage vector on the space vector plane is classified in relation to the charging\\/discharging action of DC capacitors, and a novel modulation method is suggested based on the voltage vector selection principle. The algorithm was implemented on the

  3. Fundamental Frequency Switching Control of Seven-Level Hybrid Cascaded H-bridge Multilevel Inverter

    SciTech Connect

    Du, Zhong [ORNL; Chiasson, John N [ORNL; Ozpineci, Burak [ORNL; Tolbert, Leon M [ORNL

    2009-01-01

    This paper presents a cascaded H-bridge multilevel inverter that can be implemented using only a single dc power source and capacitors. Standard cascaded multilevel inverters require n dc sources for 2n + 1 levels. Without requiring transformers, the scheme proposed here allows the use of a single dc power source (e.g., a battery or a fuel cell stack) with the remaining n-1 dc sources being capacitors, which is referred to as hybrid cascaded H-bridge multilevel inverter (HCMLI) in this paper. It is shown that the inverter can simultaneously maintain the dc voltage level of the capacitors and choose a fundamental frequency switching pattern to produce a nearly sinusoidal output. HCMLI using only a single dc source for each phase is promising for high-power motor drive applications as it significantly decreases the number of required dc power supplies, provides high-quality output power due to its high number of output levels, and results in high conversion efficiency and low thermal stress as it uses a fundamental frequency switching scheme. This paper mainly discusses control of seven-level HCMLI with fundamental frequency switching control and how its modulation index range can be extended using triplen harmonic compensation.

  4. A novel PWM scheme for a three-level voltage source inverter with GTO thyristors

    Microsoft Academic Search

    Yo-Han Lee; Bum-Seok Suh; Dong-Seok Hyun

    1996-01-01

    This paper presents a new PWM method for the three-level GTO inverters based on the space voltage vectors. With the proposed PWM method, we can minimize the harmonic components of the output voltage by avoiding the minimum pulse width limitation problem of the GTO thyristors and keeping the voltage balancing of the DC-link capacitors. The principle of the proposed PWM

  5. A novel double hysteresis-band current control for a three-level voltage source inverter

    Microsoft Academic Search

    M. Lafoz; I. J. Iglesias; C. Veganzones; M. Visiers

    2000-01-01

    This paper presents a new current control strategy for a high power three-level voltage source inverter (VSI). This control strategy consists on an extension to a three-level topology of the well-known hysteresis-band current control for a conventional two-level VSI. Line current is controlled by means of two hysteresis bands slightly displaced around the reference value. A simple calculation block decides

  6. Neural-network-based space-vector PWM of a three-level inverter covering overmodulation region and performance evaluation on induction motor drive

    Microsoft Academic Search

    Cong Wang; B. K. Bose; V. Oleschuk; S. Mondal; J. O. P. Pinto

    2003-01-01

    A multi-layer feedforward artificial neural-network (ANN) based implementation of space-vector pulse width modulation algorithm for a three-level voltage-fed inverter has been described in the paper that fully covers the undermodulation and overmodulation regions with linear transfer characteristics extending operation smoothly up to square-wave. The ANN, when implemented by dedicated application-specific IC chip, permits simple, fast and reliable operation far exceeding

  7. Control design of three-level voltage source inverter for SMES power conditioning system

    Microsoft Academic Search

    Nikola Celanovic; Dong-Ho Lee; Dengming Peng; Dusan Borojevic; Fred C. Lee

    1999-01-01

    This paper describes the control design of the power processing system for superconductive magnetic energy storage (SMES). The proposed SMES power-processing system consists of series connection of a three-level voltage source inverter and a three-level chopper. The control design enables stable high-bandwidth control of power transfer to and from the SMES coil. The issues of series connection of power converters

  8. Abstract --In this study, elimination of harmonics in a five-level diode-clamped multilevel inverter (DCMLI) has been

    E-print Network

    Tolbert, Leon M.

    much interest in motor drive applications because it needs only one common voltage source. Also, simple the output voltage levels possible for one phase of the inverter with the negative dc rail voltage V0 inverter (DCMLI) has been implemented by using fundamental modulation switching. The proposed method

  9. A three-level buck converter to regulate a high-voltage DC-to-AC inverter

    E-print Network

    Schrock, Kenneth C

    2008-01-01

    A three-level buck converter is designed and analyzed, and shown to be suitable as a high-voltage down converter as a pre-regulation stage for a 600 watt DC-to-AC power inverter. Topology selection for the inverter is ...

  10. A new zero current soft switching duty cycle controlled high frequency multi resonant inverter for consumer power applications

    Microsoft Academic Search

    Y. Miura; M. H. Hashem; E. Hiraki; K. Yasui; T. Iwai; N. A. Ahmed; Hyun Woo Lee; Mutsuo Nakaoka

    2005-01-01

    In this paper, a novel type auxiliary active edge resonant snubber assisted zero current soft switching pulse modulation single-ended push pull (SEPP) series load resonant inverter using IGBT power modules is proposed for cost effective consumer high-frequency induction heating (IH) appliances. Its operating principle in steady state is described by using each switching mode equivalent operating circuits. The new multi

  11. Cylindrical Inverted Multi-Cell (CIM) Thermionic Converter for Solar Power and Propulsion Systems

    NASA Astrophysics Data System (ADS)

    Martinez, Martin R.; Izhvanov, Oleg; Robertson, Bill; Clark, Paul N.; Streckert, Holger H.; Desplat, Jean-Louis

    2005-02-01

    Design and fabrication of a novel four cell cylindrically inverted multi-cell (CIM) solar thermionic converter for space power applications is in progress. When heated externally, the converter (8 cm diameter and 35 cm long) is capable of producing up to 492 W of electric power. The emitters operate at 2000 K while the collectors operate at 1050 K. Key components include four polycrystalline rhenium (Re) emitters, a cesium (Cs) containment vessel, and a collector trilayer. The emitters and containment vessel are both made from Re tubing. Hot Isostatic press (HIP) processing is used to produce the collector trilayer which is made up of a niobium alloy (Nb-1%Zr) base tube, plasma sprayed aluminum oxide insulation layer, and a niobium collector tube. After machining the Re emitters are brazed to the Nb collectors. The purpose of this paper is to describe the design and fabrication of the four cell CIM which will be tested at General Atomics (GA).

  12. Switching frequency optimal PWM control of a three-level inverter

    Microsoft Academic Search

    Jurgen K. Steinke

    1992-01-01

    A pulse-width-modulation (PWM) method for the control of a three-level inverter is described. The switching frequency optimal-PWM method (SFO-PWM) works with a constant carrier frequency not synchronized with fundamental stator frequency. SFO-PWM gives an optimal utilization of the mean thyristor switching frequency permitted; therefore, PWM carrier frequency may be chosen to a value of two times the permitted mean thyristor

  13. Sine-triangle vs. space vector modulation for three-level PWM voltage source inverters

    Microsoft Academic Search

    F. Wang

    2000-01-01

    This paper studies the inherent relations between sine-triangle and space vector PWM schemes for three-level voltage source inverters. It is shown that the two schemes can function equivalently through proper selection of common mode injections in the case of sine-triangle modulation, or dwell times in equivalent redundant switching states in the case of space vector modulation. Simulation and measurement results

  14. An active power filter implemented with a three-level NPC voltage-source inverter

    Microsoft Academic Search

    Victor Aburto; M. Schneider; L. Moran; Juan Dixon

    1997-01-01

    This paper presents an active power filter implemented using a three-level neutral point-clamped voltage-source inverter. The active power filter can compensate current harmonics and reactive power in medium voltage distribution systems. The paper presents the principles of operation and design criteria for both the power and control circuits. Finally, the viability of the proposed scheme is shown with computer simulation

  15. Operational Analysis and Modulation Control of Three-Level Z-Source Inverters With Enhanced Output Waveform Quality

    Microsoft Academic Search

    Poh Chiang Loh; Feng Gao; Frede Blaabjerg; Sok Wei Lim

    2009-01-01

    Three-level Z-source inverters are recent single-stage topological solutions proposed for buck-boost energy conversion with all favorable advantages of three-level switching retained. Despite their proven buck-boost capability, existing three-level Z-source inverters are either too costly with numerous passive LC elements needed or poor in spectral quality if the ldquoreduced element countrdquo (REC) variant is used. Instead of being constrained by the

  16. Multi-level modulation codes and multi-stage decoding

    NASA Technical Reports Server (NTRS)

    Lin, Shu

    1990-01-01

    Multi-level method is a powerful technique for constructing bandwidth efficient modulation codes. It allows the construction of modulation codes systematically with arbitrary large minimum squared Euclidean distance from component codes in conjunction with proper bits-to-signal mapping. If the component codes are chosen properly, the resultant modulation code not only has good minimum squared Euclidean distance but is also rich in structural properties such as: linear structure, phase invariant property, and trellis structure. A modulation code with linear structure has invariant distance distribution. Phase invariant property is useful in resolving carrier-phase ambiguity and ensuring rapid carrier-phase resynchronization after temporary loss of synchronization. It the component codes have trellis structure, the resultant multi-level modulation code also has trellis structure. Trellis structure allows decoding of a multi-level modulation code with the soft-decision Viterbi decoding algorithm. Furthermore, the multi-level structure allows decoding of a multi-level modulation code with the multi-stage decoding. This type of decoding reduces the decoding complexity. Multi-stage decoding is not optimum even though the decoding of each component is optimum. Based on the analysis and simulation results, the difference in error performance between the optimum decoding of the overall multi-level modulation code and the suboptimum multi-stage decoding of the code is very little, a fraction of dB loss.

  17. Vertically stacked multi-heterostructures of layered materials for logic transistors and complementary inverters

    PubMed Central

    Yu, Woo Jong; Li, Zheng; Zhou, Hailong; Chen, Yu; Wang, Yang; Huang, Yu; Duan, Xiangfeng

    2014-01-01

    The layered materials such as graphene have attracted considerable interest for future electronics. Here we report the vertical integration of multi-heterostructures of layered materials to enable high current density vertical field-effect transistors (VFETs). An n-channel VFET is created by sandwiching few-layer molybdenum disulfide (MoS2) as the semiconducting channel between a monolayer graphene and a metal thin film. The VFETs exhibit a room temperature on-off ratio >103, while at same time deliver a high current density up to 5,000 A/cm2, sufficient for high performance logic applications. This study offers a general strategy for the vertical integration of various layered materials to obtain both p- and n-channel transistors for complementary logic functions. A complementary inverter with larger than unit voltage gain is demonstrated by vertically stacking the layered materials of graphene, Bi2Sr2Co2O8 (p-channel), graphene, MoS2 (n-channel), and metal thin film in sequence. The ability to simultaneously achieve high on-off ratio, high current density, and logic integration in the vertically stacked multi-heterostructures can open up a new dimension for future electronics to enable three-dimensional integration. PMID:23241535

  18. An improved DTC strategy for induction motor control fed by a multi-cell voltage source inverter for high power applications

    Microsoft Academic Search

    C. A. Martins; T. A. Meynard; X. Roboam; A. S. Carvalho

    1998-01-01

    Voltage-source inverters are generally composed of only one switching cell per phase. The classical direct torque control (DTC) technique for this kind of inverter has well known advantages, but may not be used in high power systems due to the high frequency that this technique typically requires. The present work deals with the use of a multi-cell voltage-source inverter controlled

  19. 1350 IEEE TRANSACTIONS ON POWER ELECTRONICS, VOL. 24, NO. 5, MAY 2009 Three-Level Inverter-Based Shunt Active Power Filter

    E-print Network

    Mi, Chunting "Chris"

    of an active power filter (APF) based on a three-level neutral-point-clamped (NPC) voltage-source inverter-phase four-wire system, voltage-source inverter (VSI). I. INTRODUCTION ALARGE portion of the total electrical on the Fourier transformation approach. Most APFs use a standard two-level voltage-source inverter (VSI) [6], [7

  20. Conditions for Capacitor Voltage Regulation in a Five-Level Cascade Multilevel Inverter: Application to Voltage-Boost in a PM Drive

    E-print Network

    Tolbert, Leon M.

    drive using only a single DC voltage source. The input of a standard three-leg inverter is connected. INTRODUCTION The work here shows how a cascade multilevel inverter (CMLI) using only a single DC voltage sourceConditions for Capacitor Voltage Regulation in a Five-Level Cascade Multilevel Inverter

  1. MultiLevel Security Requirements for Hypervisors

    Microsoft Academic Search

    Paul A. Karger

    2005-01-01

    Using hypervisors or virtual machine monitors for security has become very popular in recent years, and a number of proposals have been made for supporting multi-level security on secure hypervisors, including PR\\/SM, NetTop, sHype, and others. This paper looks at the requirements that users of MLS systems will have and discusses their implications on the design of multi-level secure hypervisors.

  2. A Five-Level Three-Phase Cascade Multilevel Inverter Using a Single DC Source for a PM Synchronous Motor Drive

    SciTech Connect

    Ozpineci, Burak [ORNL; Chiasson, John N [ORNL; Tolbert, Leon M [ORNL

    2007-01-01

    The interest here is in using a single DC power source to construct a 3-phase 5-level cascade multilevel inverter to be used as a drive for a PM traction motor. The 5-level inverter consists of a standard 3-leg inverter (one leg for each phase) and an H-bridge in series with each inverter leg, which use a capacitor as a DC source. It is shown that one can simultaneously maintain the regulation of the capacitor voltage while achieving an output voltage waveform which is 25% higher than that obtained using a standard 3-leg inverter by itself.

  3. Adaptive Multi-level Explicit Congestion Notification

    E-print Network

    Jain, Raj

    would naturally like to have a rough estimate of the average delays in their congested routers and the level of congestion. This average queuing delay is a very importent for QoS applications. So settingAdaptive Multi-level Explicit Congestion Notification Mukundan Sridharan, Arjan Durresi, Raj Jain

  4. Multi-Level Document Visualization

    ERIC Educational Resources Information Center

    Ruecker, Stan; Homich, Eric; Sinclair, Stefan

    2005-01-01

    This paper describes a prototype system that allows readers to view an electronic text in multiple simultaneous views, providing insight at several different levels of granularity, including a reading view. This prospect display is combined with a number of tools for manipulating the text, for example by highlighting sections of interest for a…

  5. Multi-purpose grid-tied inverter with smart grid capabilities

    NASA Astrophysics Data System (ADS)

    Liyanagedera, Chamika Mihiranga

    Distributed energy storages play an important role in increasing the reliability and efficiency of the grid through means of peak load shaving, grid voltage support, and grid frequency support. It is important to have distributed energy storages that can utilize the functionalities of the modern smart grid to operate more effectively. The grid-tied inverter is one of the major components in a distributed energy storage that controls the power transfer between the grid and an energy storage device. In this research, a grid-tied inverter that can be used in distributed energy storage applications was designed, developed, and tested. This grid-tied inverter was designed with the capability to control both reactive and active power flow in either direction. The grid-tied inverter is equipped with communication capabilities so it can be remotely controlled by commands sent through a smart grid network. For demonstrative purposes, a user interface was developed to control and monitor the operation of the grid-tied inverter. Finally the operation of the grid-tied inverter was evaluated in accordance to IEEE 1547, the Standard for Interconnecting Distributed Resources with Electric Power Systems.

  6. A novel PWM scheme to eliminate common-mode voltage in three-level voltage source inverter

    Microsoft Academic Search

    K. R. M. N. Ratnayake; Y. Murai

    1998-01-01

    This paper proposes a simple PWM scheme which alleviates the common mode voltage problems of the three level inverter applications. The new scheme uses only seven voltage vectors. In addition, this method avoids the occurrence of narrow PWM pulses and gives the advantage of less complex control circuitry. Moreover the new PWM scheme shows a great potential of reducing common-mode

  7. Objective lens used in multi-wavelength, multi-layer and multi-level optical storage

    NASA Astrophysics Data System (ADS)

    Mao, Wenwei; Qi, Guosheng; Hong, Qiangning; Xu, Duanyi

    2002-09-01

    With the increasing demand of huge volume, high density and high transmission speed in optical storage, researches on multi-layer storage and multi-wavelength, multi-layer and multi-level storage in a single substrate have started both in China and abroad. This requests new feathers in optical system of optical disks. The objective lens in multi-layer storage needs compensations to varied spherical aberrations produced by varied thickness of storage layers; the objective lens in multi-wavelength and multi-layer storage needs apochromatism to broadband range. If the apochromatism is not ideal, it is needed that the spherical aberrations of multi-wavelength light are uniform and the multi-wavelength light beams are focused separately to obtain better result. A traditional micro-objective whose optical aberration is carefully corrected can be apochromatic to D, F and C in medium numerical aperture and can be used as objective lens of the optical disk of multi-wavelength, multi-layer and multi-level optical storage. This article gives an amended result based on C. G. Wyne's field flattener. The calculation result of optical aberration indicates that the spherical aberration is nearly zero and the secondary spectrum is less than 0.5 times of focal depth. It is also indicated that the MTF of a certain wavelength light matches the ideal MTF curve wherever on axis or off axis, wherever on meridian surface or on sagittal surface.

  8. Fault-tolerant operation of a 150 kW 3-level neutral-point clamped PWM inverter in a flywheel energy storage system

    Microsoft Academic Search

    Shengming Li; Longya Xu

    2001-01-01

    This paper proposes a fault-tolerant operation strategy of three-level neutral-point-clamped PWM inverters in high power, high performance, safety-critical applications. Likely faults are identified and fault-tolerant schemes based on the inherent redundancy of voltage vectors of neutral-point-clamped inverters are presented. Simulation verification is performed and shows good fault handling capability. A 150 kW neutral-point-clamped inverter is constructed for flywheel energy storage

  9. Synchronous balanced control of cascaded two-level inverters with separated DC sources

    Microsoft Academic Search

    Valentin Oleschuk; Francesco Profumo

    2007-01-01

    The paper presents results of dissemination of novel method of synchronized pulsewidth modulation (PWM) for wide-range control of dual inverter-fed motor drives with power balancing capability between dc-links. This drive topology includes two insulated dc sources (with equal or different voltages), feeding two standard three-phase inverters, connected with an open-end winding induction motor. Algorithms of synchronized PWM provide both continuous

  10. How to Invert Multi-Band, Regional Phase Amplitudes for 2-D Attenuation and Source Parameters: Tests Using the USArray

    NASA Astrophysics Data System (ADS)

    Phillips, W. Scott; Mayeda, Kevin M.; Malagnini, Luca

    2014-03-01

    We inverted for laterally varying attenuation, absolute site terms, moments and apparent stress using over 460,000 Lg amplitudes recorded by the USArray for frequencies between 0.5 and 16 Hz. Corner frequencies of Wells, Nevada, aftershocks, obtained by independent analysis of coda spectral ratios, controlled the tradeoff between attenuation and stress, while independently determined moments from St. Louis University and the University of California constrained absolute levels. The quality factor, Q, was low for coastal regions and interior volcanic and tectonic areas, and high for stable regions such as the Great Plains, and Colorado and Columbia Plateaus. Q increased with frequency, and the rate of increase correlated inversely with 1-Hz Q, with highest rates in low- Q tectonic regions, and lowest rates in high- Q stable areas. Moments matched independently determined moments with a scatter of 0.2 NM. Apparent stress ranged from below 0.01 to above 1 MPa, with means of 0.1 MPa for smaller events, and 0.3 MPa for larger events. Stress was observed to be spatially coherent in some areas; for example, stress was lower along the San Andreas fault through central and northern California, and higher in the Walker Lane, and for isolated sequences such as Wells. Variance reduction relative to 1-D models ranged from 50 to 90 % depending on band and inversion method. Parameterizing frequency dependent Q as a power law produced little misfit relative to a collection of independent, multi-band Q models, and performed better than the omega-square source parameterization in that sense. Amplitude residuals showed modest, but regionally coherent patterns that varied from event to event, even between those with similar source mechanisms, indicating a combination of focal mechanism, and near source propagation effects played a role. An exception was the Wells mainshock, which produced dramatic amplitude patterns due to its directivity, and was thus excluded from the inversions. The 2-D Q plus absolute site models can be used for high accuracy, broad area source spectra, magnitude and yield estimation, and, in combination with models for all regional phases, can be used to improve discrimination, in particular for intermediate bands that allow coverage to be extended beyond that available for high frequency P-to-S discriminants.

  11. Sine-triangle versus space-vector modulation for three-level PWM voltage-source inverters

    Microsoft Academic Search

    Fei Wang

    2002-01-01

    This paper studies the inherent relations between sine-triangle and space-vector pulsewidth modulation schemes for three-level voltage-source inverters. It is shown that the two schemes can function equivalently through proper selection of common-mode injections in the case of sine-triangle modulation, or dwell times in equivalent redundant switching states in the case of space-vector modulation. Simulation and measurement results illustrate that understanding

  12. A state-space model for the comprehensive dynamic analysis of three-level voltage-source inverters

    Microsoft Academic Search

    J. Bordonau; M. Cosan; D. Borojevic; H. Mao; F. C. Lee

    1997-01-01

    A new and comprehensive model of the three-level voltage-source inverter is presented. The dynamics of the complete system is considered, including the DC-link side and the load side. This model is a tool for a full control of the system. The model uses the D-Q transformation. Steady-state and small-signal analysis are obtained and the simulation results are given

  13. Multi-Level TESLA: Broadcast Authentication for Distributed Sensor Networks

    E-print Network

    Ning, Peng

    Multi-Level µTESLA: Broadcast Authentication for Distributed Sensor Networks DONGGANG LIU and PENG named multi-level µTESLA based on µTESLA, a broadcast authentication protocol whose scalability is limited by its unicast-based initial parameter distribution. Multi-level µTESLA satisfies several nice

  14. Electronic multi-purpose material level sensor

    DOEpatents

    McEwan, T.E.

    1997-03-11

    The present electronic multi-purpose material level sensor is based on time domain reflectometry (TDR) of very short electrical pulses. Pulses are propagated along a transmission line that is partially immersed in a liquid, powder, or other substance such as grain in a silo. The time difference of the reflections at the start of the transmission line and the air/liquid interface are used to determine levels to better than 0.01 inch. The sensor is essentially independent of circuit element and temperature variations, and can be mass produced at an extremely low price. The transmission line may be a Goubau line, microstrip, coaxial cable, twin lead, CPS or CPW, and may typically be a strip placed along the inside wall of a tank. The reflected pulses also contain information about strata within the liquid such as sludge-build-up at the bottom of an oil tank. 9 figs.

  15. Electronic multi-purpose material level sensor

    DOEpatents

    McEwan, Thomas E. (Livermore, CA)

    1997-01-01

    The present electronic multi-purpose material level sensor is based on time domain reflectometry (TDR) of very short electrical pulses. Pulses are propagated along a transmission line that is partially immersed in a liquid, powder, or other substance such as grain in a silo. The time difference of the reflections at the start of the transmission line and the air/liquid interface are used to determine levels to better than 0.01 inch. The sensor is essentially independent of circuit element and temperature variations, and can be mass produced at an extremely low price. The transmission line may be a Goubau line, microstrip, coaxial cable, twin lead, CPS or CPW, and may typically be a strip placed along the inside wall of a tank. The reflected pulses also contain information about strata within the liquid such as sludge-build-up at the bottom of an oil tank.

  16. Investigation of a high-power three-level quasi-resonant DC-link voltage-source inverter

    Microsoft Academic Search

    Thomas Brückner; Steffen Bernet

    2001-01-01

    This paper investigates the feasibility of a quasi-resonant DC-link soft-switching principle for voltage-source inverters (VSIs) in the megawatt power range. An evaluation of a three-level quasi-resonant DC-link VSI (3L-QRDCWSI) featuring integrated gate-commutated thyristors (IGCTs) and a comparison-to a commercially available three-level IGCT-VSI is presented. Extensive loss measurements of IGCTs under hard- and soft-switching conditions are the basis for the design

  17. Optimal resource leveling of multi-resource projects

    Microsoft Academic Search

    M. A. Younis; B. Saad

    1996-01-01

    The main aim of this study is to solve the problem of optimal resource leveling for multi source projects. This work focuses on resource leveling. The mathematical model developed can handle multi-resource projects. To help solve multi-resource projects a computer program was developed as an aid to the analysis of the model.

  18. The carrier-based PWM method for voltage balance of flying capacitor multilevel inverter

    Microsoft Academic Search

    Sang-Gil Lee; Dae-Wook Kang; Yo-Han Lee; Dong-Seok Hyun

    2001-01-01

    This paper proposes a new solution using a carrier-based PWM method to solve the most serious problem of flying capacitor multi-level inverters, that is the unbalance of capacitor voltages. The voltage unbalance occurs due to the difference of each capacitor's charging and discharging time applied to the flying capacitor inverter. The new solution controls the variation of capacitor voltages into

  19. An advanced static var compensator based on a three level IGBT inverter modelling analysis and active power filtering

    NASA Astrophysics Data System (ADS)

    Draou, Azeddine

    2012-12-01

    This paper presents the dynamic performance analysis of an Advanced Static Var Compensator (ASVC) using three-level neutral point-clamped voltage source inverter. The paper presents the principles of operating and the method of reference currents generation. The dynamic behaviour of the system is further analysed using Matlab/Simulink with SimPower Systems toolbox through a set of simulation tests. The results obtained have been applied to an active power filter which might lead to the design of a robust controller for current harmonics and reactive power applications

  20. Invert Recommendations The Invert project

    E-print Network

    #12;Invert ­ Recommendations The Invert project: Research project within the Altener Program and Innovation Research, Germany Contact/Information: Lukas.Kranzl@tuwien.ac.at www.invert.at Imprint: Energy. Gusshausstrasse 25-29 / 373-2, A-1040 Vienna, Austria Printed in Austria ­ June 2005 #12;Invert ­ Recommendations

  1. Fuzzy Control of the Permanent Magnet Synchronous Machine Singularly Perturbed Fed By a Three Level Inverter

    NASA Astrophysics Data System (ADS)

    Massoum, Ahmed; Meroufel, Abdelkader; Wira, Patrice; Fellah, Mohammed Karim

    2012-05-01

    In this paper, we present the control technique based on the singular perturbation technique controlled by a fuzzy regulator applied to the permanent magnet synchronous machine (PMSM). This technique applied to the PMSM conducts to a separation of the variables into disjoined subset or two separated models: one having a slow dynamics, and the other a fast dynamics. To ensure certain robustness to the decoupled control system based on these techniques, the control speed and the Id current is carried out by fuzzy regulators. A qualitative analysis of the principal variables evolution describing the behavior of the global system (PMSM-Inverter with MLI-Control) and its robustness is developed by several tests of digital simulation in last stage.

  2. A Multi-Level Approach for Evaluating Internet Topology Generators

    E-print Network

    Fahmy, Sonia

    generators, and show that the recent Internet clustering coefficient and average distance are not timeA Multi-Level Approach for Evaluating Internet Topology Generators Ryan Rossi Department for analyzing Internet topologies and their evolution. Our multi-level framework includes novel measures

  3. Multi-Level Reconfiguration in the DANAH Assistive System

    E-print Network

    Paris-Sud XI, Université de

    Multi-Level Reconfiguration in the DANAH Assistive System Sa¨id LANKRI European University reconfiguration. This papers deals with service reconfiguration in smart homes. It presents a multi-level approach in which both off-line and on-line reconfiguration schemes are used to gradually recover from failed

  4. Multi-Level Annotation of Natural Scenes Using Dominant Image

    E-print Network

    Fan, Jianping

    Multi-Level Annotation of Natural Scenes Using Dominant Image Compounds and Semantic Concepts at Charlotte #12;Outline of Presentation Research Motivation Semantic Image Representation Semantic Image Concept Modeling Adaptive EM Algorithm for Classifier Training Multi-Level Image Annotation Conclusions

  5. PARALLEL ALGORITHMS FOR A MULTI-LEVEL NETWORK OPTIMIZATION PROBLEM

    E-print Network

    Cruz, Frederico

    -integer programming; G.2.2. [Discrete Mathematics]: Graph Theory-network problems; G.4.[Mathematics of ComputingPARALLEL ALGORITHMS FOR A MULTI-LEVEL NETWORK OPTIMIZATION PROBLEM F.R.B. CRUZa, * and G.R. MATEUSb­MG, Brazil (Received 15 February 2000; In final form 12 March 2001) Multi-level network optimization (MLNO

  6. Milliwatt dc/dc Inverter

    NASA Technical Reports Server (NTRS)

    Mclyman, C. W.

    1983-01-01

    Compact dc/dc inverter uses single integrated-circuit package containing six inverter gates that generate and amplify 100-kHz square-wave switching signal. Square-wave switching inverts 10-volt local power to isolated voltage at another desired level. Relatively high operating frequency reduces size of filter capacitors required, resulting in small package unit.

  7. Storm surge simulation by means of multi-level model

    SciTech Connect

    Tabeta, S.; Fujino, M. [Univ. of Tokyo (Japan). Dept. of Naval Architecture and Ocean Engineering

    1993-12-31

    A multi-level simulation program which is able to treat domains of different mesh size was applied to calculation of storm surge. The characteristics of multi-level model in the calculation of wind driven current were demonstrated for the case of a simple rectangular basin. Then the model was applied to calculation of storm surge in Tokyo Bay, and the results were compared with those of two-dimensional model to show the availability of multi-level model for clarifying current field in storm surge. Furthermore, tidal effect on storm surge and the effect of vertical mixture on vertical distribution of current were examined.

  8. Abstract-A fault detection and reconfiguration technique for a cascaded H-bridge 11-level inverter drives during faulty condition

    E-print Network

    Tolbert, Leon M.

    Abstract-A fault detection and reconfiguration technique for a cascaded H-bridge 11-level inverter can be used as a diagnostic signal to detect faults and their locations. AI-based techniques are used to perform the fault classification. A neural network (NN) classification is applied to the fault diagnosis

  9. The Ohio State University SPECTS 2004 AMECN 1 Adaptive MultiAdaptive Multi--Level ExplicitLevel Explicit

    E-print Network

    Jain, Raj

    The Ohio State University SPECTS 2004 ­ AMECN 1 Adaptive MultiAdaptive Multi--Level Explicit Professor Ohio-State University Columbus, OH 43210-1277 These Slides are available at http:/www.cse.ohio-state.edu/~jain/papers/amecn.htm Arjan Durresi, Mukundan Sridharan and Raj Jain Presented by Raj JainRaj Jain #12;The Ohio State

  10. Inverted Oscillator

    E-print Network

    C. Yuce; A. Kilic; A. Coruh

    2007-03-25

    The inverted harmonic oscillator problem is investigated quantum mechanically. The exact wave function for the confined inverted oscillator is obtained and it is shown that the associated energy eigenvalues are discrete and it is given as a linear function of the quantum number $n$.

  11. Inverted Perceptual Judgment of Nociceptive Stimuli at Threshold Level following Inconsistent Cues

    PubMed Central

    Walter, Carmen; Dimova, Violeta; Bu, Julia; Parnham, Michael J.; Oertel, Bruno G.; Lötsch, Jörn

    2015-01-01

    Objective The perception of pain is susceptible to modulation by psychological and contextual factors. It has been shown that subjects judge noxious stimuli as more painful in a respective suggestive context, which disappears when the modifying context is resolved. However, a context in which subjects judge the painfulness of a nociceptive stimulus in exactly the opposite direction to that of the cues has never been shown so far. Methods Nociceptive stimuli (300 ms intranasal gaseous CO2) at the individual pain threshold level were applied after a visual cue announcing the stimulus as either “no pain”, merely a “stimulus”, or “pain”. Among the stimuli at threshold level, other CO2 stimuli that were clearly below or above pain threshold were randomly interspersed. These were announced beforehand in 12 subjects randomly with correct or incorrect cues, i.e., clearly painful or clearly non-painful stimuli were announced equally often as not painful or painful. By contrast, in a subsequent group of another 12 subjects, the stimuli were always announced correctly with respect to the evoked pain. Results The random and often incorrect announcement of stimuli clearly below or above pain threshold caused the subjects to rate the stimuli at pain-threshold level in the opposite direction of the cue, i.e., when the stimuli were announced as “pain” significantly more often than as non-painful and vice versa (p < 10-4). By contrast, in the absence of incongruence between announcement and perception of the far-from-threshold stimuli, stimuli at pain threshold were rated in the cued direction. Conclusions The present study revealed the induction of associations incongruent with a given message in the perception of pain. We created a context of unreliable cues whereby subjects perceived the stimulus opposite to that suggested by a prior cue, i.e., potentially nociceptive stimuli at pain threshold level that were announced as painful were judged as non-painful and vice versa. These findings are consistent with reported data on the effects of distrust on non-painful cognitive responses. PMID:26147732

  12. Physiological levels of diacylglycerols in phospholipid membranes induce membrane fusion and stabilize inverted phases

    SciTech Connect

    Siegel, D.P.; Banschbach, J.; Alford, D.; Ellens, H.; Lis, L.J.; Quinn, P.J.; Yeagle, P.L.; Bentz, J. (Procter and Gamble Company, Cincinnati, OH (USA))

    1989-05-02

    In a previous paper, it was shown that liposome fusion rates are substantially enhanced under the same conditions which induce isotropic {sup 31}P NMR resonances in multilamellar dispersions of the same lipid. Both of these phenomena occur within the same temperature interval, {Delta}T{sub I}, below the L{sub {alpha}}/H{sub II} phase transition temperature, T{sub H}. T{sub H} and {Delta}T{sub I} can be extremely sensitive to the lipid composition. The present work shows that 2 mol % of diacylglycerols like those produced by the phosphatidylinositol cycle in vivo can lower T{sub H}, {Delta}T{sub I}, and the temperature for fast membrane fusion by 15-20{degree}C. N-Monomethylated dioleoylphosphatidylethanolamine is used as a model system. These results show that physiological levels of diacylglycerols can substantially increase the susceptibility of phospholipid membranes to fusion. This suggests that, in addition to their role in protein kinase C activation, diacylglycerols could play a more direct role in the fusion event during stimulus-exocytosis coupling in vivo.

  13. Multi Core Design for Chip Level Multiprocessing

    NASA Astrophysics Data System (ADS)

    Fossum, Tryggve

    Chip level integration continues to be a driving force in the computer industry. It lowers the cost and increases performance of computer systems, creating a remarkable rate of improvement in all processors, from handheld devices to supercomputers. Processor chips now (in 2009) contain up to two billion transistors. Gordon Moore outlined a roadmap for chip level integration in 1965, which has become known as Moore's Law. It predicts that the density of transistors in a silicon chip will double every process generation. It has become the heartbeat of the semiconductor industry.

  14. Multi-Level Selective Classes for Gifted Students

    ERIC Educational Resources Information Center

    Henderson, Lesley

    2007-01-01

    Research was undertaken to examine the level of support and general attitudes towards multi-level selective classes for gifted students amongst the staff and parents of an independent (non-government) boys' Preparatory school, located in Adelaide, South Australia. Questionnaires were sent to all parents and staff in the Preparatory school and…

  15. Multilevel DC link inverter

    DOEpatents

    Su, Gui-Jia

    2003-06-10

    A multilevel DC link inverter and method for improving torque response and current regulation in permanent magnet motors and switched reluctance motors having a low inductance includes a plurality of voltage controlled cells connected in series for applying a resulting dc voltage comprised of one or more incremental dc voltages. The cells are provided with switches for increasing the resulting applied dc voltage as speed and back EMF increase, while limiting the voltage that is applied to the commutation switches to perform PWM or dc voltage stepping functions, so as to limit current ripple in the stator windings below an acceptable level, typically 5%. Several embodiments are disclosed including inverters using IGBT's, inverters using thyristors. All of the inverters are operable in both motoring and regenerating modes.

  16. HIGH-LEVEL MULTI-STEP INVERTER OPTIMIZATION, USING A MINIMUM NUMBER OF POWER TRANSISTORS.

    E-print Network

    Catholic University of Chile (Universidad Católica de Chile)

    . INTRODUCTION Power electronics devices contribute with important part of harmonics in all kind of applications used to control modern static converters such as machine drives, power factor compensators or active with the respective load are required. In other words, neither the voltage nor the current waveforms are as expected

  17. A comprehensive study of neutral-point voltage balancing problem in three-level neutral-point-clamped voltage source PWM inverters

    Microsoft Academic Search

    Nikola Celanovic; Dushan Boroyevich

    2000-01-01

    This paper explores the fundamental limitations of the neutral-point voltage balancing problem for different loading conditions of three-level voltage source inverters. A new model in the DQ coordinate frame utilizing current switching functions is developed as a means to investigate theoretical limitations and to offer a more intuitive insight into the problem. The low-frequency ripple of the neutral point caused

  18. Multi-Level Alert Clustering for Intrusion Detection Sensor Data*

    E-print Network

    Siraj, Ambareen

    Multi-Level Alert Clustering for Intrusion Detection Sensor Data* Ambareen Siraj Rayford B. Vaughn clustering and alert correlation. In this paper, we address the alert clustering aspect of sensor data fusion multiple, diverse sensors. Intelligent sensor fusion of runtime behavior data is critical for such systems

  19. Multi-Accuracy Power and Performance Transaction-Level Modeling

    Microsoft Academic Search

    Giovanni Beltrame; Donatella Sciuto; Cristina Silvano

    2007-01-01

    This paper introduces a modeling and simulation technique that extends transaction-level modeling (TLM) to support multi-accuracy models and power estimation. This approach provides different combinations of power and performance models, and the switching of model accuracy during simulation, allowing the designer to trade off between simulation accuracy and speed at runtime. This is particularly useful during the exploration phase of

  20. Control challenges in multi-level adaptive video streaming

    Microsoft Academic Search

    Dylan McNamee; Charles Krasic; Kang Li; Ashvin Goel; Erik Walthinsen; David Steere; Jonathan Walpole

    2000-01-01

    Streaming video is one of the fastest-growing applications of the Internet. The Internet's diversity and dynamism demands that video streams adapt to ensure maximum quality at all times. This paper describes the control challenges we have encountered in the Quasar project's “multi-level” adaptive streaming video player. We first describe the framework and environment of the player. This framework uses software

  1. Inverted Channel

    NASA Technical Reports Server (NTRS)

    2005-01-01

    This Mars Global Surveyor (MGS) Orbiter Camera (MOC) image shows an inverted channel running down, through a valley in the Memnonia Sulci region of Mars. The original channel is gone, as are the rocks through which it cut. The channel floor and/or the material that filled the channel was more resistant to erosion, and thus left standing high as a ridge. Inverted channels and valleys are common on Mars. Many old valley networks have been filled, buried, and in some cases, exhumed and inverted, all across the planet.

    Location near: 11.4oS, 174.4oW Image width: 3.0 km (1.9 mi) Illumination from: upper left Season: Southern Winter

  2. Simplified High-Power Inverter

    NASA Technical Reports Server (NTRS)

    Edwards, D. B.; Rippel, W. E.

    1984-01-01

    Solid-state inverter simplified by use of single gate-turnoff device (GTO) to commutate multiple silicon controlled rectifiers (SCR's). By eliminating conventional commutation circuitry, GTO reduces cost, size and weight. GTO commutation applicable to inverters of greater than 1-kilowatt capacity. Applications include emergency power, load leveling, drives for traction and stationary polyphase motors, and photovoltaic-power conditioning.

  3. A Simple On-line SHE PWM With Extension to Six Step Mode in Two-Level Inverters

    Microsoft Academic Search

    Nguyen van Nho; Myung Joong Youn

    2005-01-01

    The Selective Harmonic Elimination (SHE) PWM technique has become a significant PWM method for less switching loss for voltage source inverter. For off-line approach, the various sets of commutation angles in relation to modulation index are commonly determined in advance and look-up tables are required. This trouble can be avoided in on-line approach. The paper presents a simple on-line SHE

  4. Device-Level Models Using Multi-Valley Effective Mass

    NASA Astrophysics Data System (ADS)

    Baczewski, Andrew D.; Frees, Adam; Gamble, John King; Gao, Xujiao; Jacobson, N. Tobias; Mitchell, John A.; Montaño, Inès; Muller, Richard P.; Nielsen, Erik

    2015-03-01

    Continued progress in quantum electronics depends critically on the availability of robust device-level modeling tools that capture a wide range of physics and effective mass theory (EMT) is one means of building such models. Recent developments in multi-valley EMT show quantitative agreement with more detailed atomistic tight-binding calculations of phosphorus donors in silicon (Gamble, et. al., arXiv:1408.3159). Leveraging existing PDE solvers, we are developing a framework in which this multi-valley EMT is coupled to an integrated device-level description of several experimentally active qubit technologies. Device-level simulations of quantum operations will be discussed, as well as the extraction of process matrices at this level of theory. The authors gratefully acknowledge support from the Sandia National Laboratories Truman Fellowship Program, which is funded by the Laboratory Directed Research and Development (LDRD) Program. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Security Administration under contract DE-AC04-94AL85000.

  5. Neighborhoods and child maltreatment: a multi-level study

    Microsoft Academic Search

    Claudia J. Coulton; Jill E. Korbin; Marilyn Su

    1999-01-01

    Objective: To better understand how neighborhood and individual factors are related to child maltreatment.Method: Using an ecological framework, a multi-level model (Hierarchical Linear Modeling) was used to analyze neighborhood structural conditions and individual risk factors for child abuse and neglect. Parents (n = 400) of children under the age of 18 were systematically selected from 20 randomly selected census-defined block

  6. On decoding of multi-level MPSK modulation codes

    NASA Technical Reports Server (NTRS)

    Lin, Shu; Gupta, Alok Kumar

    1990-01-01

    The decoding problem of multi-level block modulation codes is investigated. The hardware design of soft-decision Viterbi decoder for some short length 8-PSK block modulation codes is presented. An effective way to reduce the hardware complexity of the decoder by reducing the branch metric and path metric, using a non-uniform floating-point to integer mapping scheme, is proposed and discussed. The simulation results of the design are presented. The multi-stage decoding (MSD) of multi-level modulation codes is also investigated. The cases of soft-decision and hard-decision MSD are considered and their performance are evaluated for several codes of different lengths and different minimum squared Euclidean distances. It is shown that the soft-decision MSD reduces the decoding complexity drastically and it is suboptimum. The hard-decision MSD further simplifies the decoding while still maintaining a reasonable coding gain over the uncoded system, if the component codes are chosen properly. Finally, some basic 3-level 8-PSK modulation codes using BCH codes as component codes are constructed and their coding gains are found for hard decision multistage decoding.

  7. Fundamental-Frequency-Modulated Six-Level Diode-Clamped Multilevel Inverter for Three-Phase Stand-Alone Photovoltaic System

    SciTech Connect

    Ozdemir, Engin [ORNL; Ozdemir, Sule [Oak Ridge National Laboratory (ORNL); Tolbert, Leon M [ORNL

    2009-01-01

    This paper presents a fundamental-frequency-modulated diode-clamped multilevel inverter (DCMLI) scheme for a three-phase stand-alone photovoltaic (PV) system. The system consists of five series-connected PV modules, a six-level DCMLI generating fundamental-modulation staircase three-phase output voltages, and a three-phase induction motor as the load. In order to validate the proposed concept, simulation studies and experimental measurements using a small-scale laboratory prototype are also presented. The results show the feasibility of the fundamental frequency switching application in three-phase stand-alone PV power systems.

  8. Invertible Motion Blur in Video Amit Agrawal

    E-print Network

    Agrawal, Amit

    Invertible Motion Blur in Video Amit Agrawal Yi Xu Mitsubishi Electric Research Labs (MERL Figure 1: By simply varying the exposure time for video frames, multi-image deblurring can be made invertible. (Left) Varying exposure photos of a moving car. Notice the change in illumination and the blur

  9. Overload protection system for power inverter

    NASA Technical Reports Server (NTRS)

    Nagano, S. (inventor)

    1977-01-01

    An overload protection system for a power inverter utilized a first circuit for monitoring current to the load from the power inverter to detect an overload and a control circuit to shut off the power inverter, when an overload condition was detected. At the same time, a monitoring current inverter was turned on to deliver current to the load at a very low power level. A second circuit monitored current to the load, from the monitoring current inverter, to hold the power inverter off through the control circuit, until the overload condition was cleared so that the control circuit may be deactivated in order for the power inverter to be restored after the monitoring current inverter is turned off completely.

  10. Efficient Multidisciplinary Analysis Procedure Using Multi-Level Parallelization Approach

    NASA Technical Reports Server (NTRS)

    Byun, Chansup; Hatay, Ferhat; Farhangnia, Mehrdad; Guruswamy, Guru; VanDalsem, William R. (Technical Monitor)

    1997-01-01

    Multidisciplinary applications are suitable for parallel computing environment by adopting the domain decomposition method. Immediately, a multidisciplinary application can be parallelized by solving each discipline separately. In order to perform coupled multidisciplinary analysis, coupling of each discipline can be accomplished by exchanging boundary data at the interfaces. This is regarded as discipline-level parallelization. Next level could be a "coarse-grain" parallelization of each discipline, which mainly depends on the physical geometry and nature of each discipline. For example, it is almost impossible for structured-grid based computational fluid dynamics codes to do flow analysis of an aircraft by using a single grid because of the complexity of its configuration. Thus, multi-block grid is commonly used to describe the details of complex geometry. Similarly, in structural analysis, the structure is frequently subdivided into substructures. Thus, the computation of each subdomain can be easily parallelized since each subdomain is solved separately independent of other domains. The parallelization is accomplished by solving each subdomain separately on a separate processor and exchanging the boundary conditions at domain interfaces periodically. However, the physical decomposition of the domain introduces explicit boundary conditions at the domain interfaces. This is not desirable for critical areas such as those containing shock waves or flow separations. Thus, a "fine-grain" parallelization is introduced to overcome this problem. The "fine-grain" parallelization is one that solves exactly the same system of equations of a subdomain by using more than one processors without introducing any explicit boundary conditions. An efficient multidisciplinary analysis procedure can be accomplished by successfully combining the above multi-level parallelism. A multidisciplinary analysis code, ENSAERO developed at NASA Ames Research Center is used in this study to implement the proposed approach. The communication data structure required for the proposed approach will be studied in detail. This work will demonstrate the feasibility of using multi-level parallelization approach in multidisciplinary analysis applications.

  11. UNIVERSITY OF CALGARY Context-Aware Personal Navigation Services Using Multi-level Sensor Fusion Algorithms

    E-print Network

    Calgary, University of

    UNIVERSITY OF CALGARY Context-Aware Personal Navigation Services Using Multi-level Sensor Fusion adaptation. The proposed context-aware PNS approach is using low-cost multi-sensor data in a multi-level, and finding the most accurate context. The context reasoning technique uses a fuzzy decision-level fusion

  12. Multi-Level Steganography: Improving Hidden Communication in Networks

    E-print Network

    Fraczek, Wojciech; Szczypiorski, Krzysztof

    2011-01-01

    The paper presents Multi-Level Steganography (MLS), which defines a new concept for hidden communication. In MLS, at least two steganographic methods are utilised simultaneously, in such a way that one method (called the upper-level) serves as a carrier for the second one (called the lower-level). Such a relationship between two (or more) information hiding solutions has several potential benefits. The most important is that the lower-level method steganographic bandwidth can be utilised to make the steganogram unreadable even after the detection of the upper-level method: e.g., it can carry a cryptographic key that deciphers the steganogram carried by the upper-level one. It can also be used to provide the steganogram with integrity. Another important benefit is that the lower-layer method may be used as a signalling channel in which to exchange information that affects the way that the upper-level method functions, thus possibly making the steganographic communication harder to detect. MLS is presented in t...

  13. Coercive Region-level Registration for Multi-modal Images

    E-print Network

    Chen, Yu-Hui; Newstadt, Gregory; Simmons, Jeffrey; hero, Alfred

    2015-01-01

    We propose a coercive approach to simultaneously register and segment multi-modal images which share similar spatial structure. Registration is done at the region level to facilitate data fusion while avoiding the need for interpolation. The algorithm performs alternating minimization of an objective function informed by statistical models for pixel values in different modalities. Hypothesis tests are developed to determine whether to refine segmentations by splitting regions. We demonstrate that our approach has significantly better performance than the state-of-the-art registration and segmentation methods on microscopy images.

  14. Multi-level Bayesian analyses for single- and multi-vehicle freeway crashes.

    PubMed

    Yu, Rongjie; Abdel-Aty, Mohamed

    2013-09-01

    This study presents multi-level analyses for single- and multi-vehicle crashes on a mountainous freeway. Data from a 15-mile mountainous freeway section on I-70 were investigated. Both aggregate and disaggregate models for the two crash conditions were developed. Five years of crash data were used in the aggregate investigation, while the disaggregate models utilized one year of crash data along with real-time traffic and weather data. For the aggregate analyses, safety performance functions were developed for the purpose of revealing the contributing factors for each crash type. Two methodologies, a Bayesian bivariate Poisson-lognormal model and a Bayesian hierarchical Poisson model with correlated random effects, were estimated to simultaneously analyze the two crash conditions with consideration of possible correlations. Except for the factors related to geometric characteristics, two exposure parameters (annual average daily traffic and segment length) were included. Two different sets of significant explanatory and exposure variables were identified for the single-vehicle (SV) and multi-vehicle (MV) crashes. It was found that the Bayesian bivariate Poisson-lognormal model is superior to the Bayesian hierarchical Poisson model, the former with a substantially lower DIC and more significant variables. In addition to the aggregate analyses, microscopic real-time crash risk evaluation models were developed for the two crash conditions. Multi-level Bayesian logistic regression models were estimated with the random parameters accounting for seasonal variations, crash-unit-level diversity and segment-level random effects capturing unobserved heterogeneity caused by the geometric characteristics. The model results indicate that the effects of the selected variables on crash occurrence vary across seasons and crash units; and that geometric characteristic variables contribute to the segment variations: the more unobserved heterogeneity have been accounted, the better classification ability. Potential applications of the modeling results from both analysis approaches are discussed. PMID:23727550

  15. A simple method for parallel operation of inverters

    Microsoft Academic Search

    Heinz van der Broeck; Ulrich Boeke

    1998-01-01

    Telecom applications require uninterruptible power supplies for different power levels. If the number of different converter systems should be kept low, parallel operation of inverters is of interest. Thus, a master\\/slave architecture of an inverter system is presented which allows parallel operation of an arbitrary number of inverter modules by a simple control method. All inverter modules can be equal

  16. Does the world need yet another solar inverter concept? Intermediate size inverters have grown; now there is a

    E-print Network

    King, Roger

    ABSTRACT Does the world need yet another solar inverter concept? Intermediate size inverters have grown; now there is a MegaWatt in a box, and on the other end of the scale, panel level MicroInverters that couple to a large central inverter, and increased attention has been paid to the critical role

  17. Multi-Level Bitmap Indexes for Flash Memory Storage

    SciTech Connect

    Wu, Kesheng; Madduri, Kamesh; Canon, Shane

    2010-07-23

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

  18. Evolution of neuroarchitecture, multi-level analyses and calibrative reductionism

    PubMed Central

    Berntson, Gary G.; Norman, Greg J.; Hawkley, Louise C.; Cacioppo, John T.

    2012-01-01

    Evolution has sculpted the incredibly complex human nervous system, among the most complex functions of which extend beyond the individual to an intricate social structure. Although these functions are deterministic, those determinants are legion, heavily interacting and dependent on a specific evolutionary trajectory. That trajectory was directed by the adaptive significance of quasi-random genetic variations, but was also influenced by chance and caprice. With a different evolutionary pathway, the same neural elements could subserve functions distinctly different from what they do in extant human brains. Consequently, the properties of higher level neural networks cannot be derived readily from the properties of the lower level constituent elements, without studying these elements in the aggregate. Thus, a multi-level approach to integrative neuroscience may offer an optimal strategy. Moreover, the process of calibrative reductionism, by which concepts and understandings from one level of organization or analysis can mutually inform and ‘calibrate’ those from other levels (both higher and lower), may represent a viable approach to the application of reductionism in science. This is especially relevant in social neuroscience, where the basic subject matter of interest is defined by interacting organisms across diverse environments. PMID:23386961

  19. Application of single-level and multi-level Rasch models using the lme4 package.

    PubMed

    Lamprianou, Iasonas

    2013-01-01

    The aim of the article is to illustrate how researchers may use the lme4 package to run multilevel Rasch models. The lme4 package is a popular open-source software and is frequently used by researchers around the world to fit generalized mixed-effects models with crossed or partially crossed random effects. The article starts with a short discussion of the reasons why a researcher might, sometimes, be motivated to use a multi-level Rasch model and presents a practical example using empirical data. The main features of the lme4 package are presented, and finally, the paper presents information about other open-source software that could alternatively be used to fit multi-level Rasch models. PMID:23442329

  20. Multi-level Ground Glass Nodule Detection and Segmentation in CT Lung Images

    E-print Network

    Corso, Jason J.

    Multi-level Ground Glass Nodule Detection and Segmentation in CT Lung Images Yimo Tao1,2 , Le Lu1 is labor-intensive and problematic. In this paper, we propose a novel multi-level learning-based framework for automatic detection and segmentation of GGN in lung CT images. Our main contributions are: firstly, a multi

  1. Power inverters

    DOEpatents

    Miller, David H. (Redondo Beach, CA); Korich, Mark D. (Chino Hills, CA); Smith, Gregory S. (Woodland Hills, CA)

    2011-11-15

    Power inverters include a frame and a power module. The frame has a sidewall including an opening and defining a fluid passageway. The power module is coupled to the frame over the opening and includes a substrate, die, and an encasement. The substrate includes a first side, a second side, a center, an outer periphery, and an outer edge, and the first side of the substrate comprises a first outer layer including a metal material. The die are positioned in the substrate center and are coupled to the substrate first side. The encasement is molded over the outer periphery on the substrate first side, the substrate second side, and the substrate outer edge and around the die. The encasement, coupled to the substrate, forms a seal with the metal material. The second side of the substrate is positioned to directly contact a fluid flowing through the fluid passageway.

  2. Inverted Valley

    NASA Technical Reports Server (NTRS)

    2005-01-01

    15 December 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a somewhat sinuous, nearly flat-topped ridge, located in eastern Arabia Terra. The ridgetop was once the floor of a valley, perhaps carved by running water. The valley floor, or material that covered the floor, was more resistant to erosion than the surrounding rock into which the valley was cut. Thus, over time, the valley disappeared and its floor was left standing high as a ridge. Inverted valleys are common on Mars; they also occur on Earth.

    Location near: 10.8oN, 313.2oW Image width: width: 3 km (1.9 mi) Illumination from: lower left Season: Northern Winter

  3. Inverted Valley

    NASA Technical Reports Server (NTRS)

    2005-01-01

    10 September 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows an inverted valley in eastern Arabia Terra. The relatively flat-topped ridge that runs down much of the length of this picture was once the floor, or a material covering the floor, of an ancient martian valley. The floor material was harder and more resistant to erosion than the rocks into which the valley had been cut. Thus, erosion removed the rocks that were cut by the valley, and then removed additional rocks that were lower than the valley floor, leaving what was once a valley as a high-standing ridge.

    Location near: 11.4oN, 312.9oW Image width: width: 3 km (1.9 mi) Illumination from: lower left Season: Northern Autumn

  4. Stream, Inverted

    NASA Technical Reports Server (NTRS)

    2006-01-01

    27 July 2006 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows the inverted, eroded remains of a channel -- now standing as a complex ridge that runs across the middle of this scene -- in dust-mantled terrain west of Sinus Meridiani, Mars. The original channel might have been carved by running water, but too little detail remains today to provide any certainty as to whether water was the culprit.

    Location near: 5.6oN, 7.6oW Image width: 3 km (1.9 mi) Illumination from: upper left Season: Northern Spring

  5. 2.3-MW Medium-Voltage, Three-Level Wind Energy Inverter Applying a Unique Bus Structure and 4.5-kV Si/SiC Hybrid Isolated Power Modules: Preprint

    SciTech Connect

    Erdman, W.; Keller, J.; Grider, D.; VanBrunt, E.

    2014-11-01

    A high-efficiency, 2.3-MW, medium-voltage, three-level inverter utilizing 4.5-kV Si/SiC (silicon carbide) hybrid modules for wind energy applications is discussed. The inverter addresses recent trends in siting the inverter within the base of multimegawatt turbine towers. A simplified split, three-layer laminated bus structure that maintains low parasitic inductances is introduced along with a low-voltage, high-current test method for determining these inductances. Feed-thru bushings, edge fill methods, and other design features of the laminated bus structure provide voltage isolation that is consistent with the 10.4-kV module isolation levels. Inverter efficiency improvement is a result of the (essential) elimination of the reverse recovery charge present in 4.5-kV Si PIN diodes, which can produce a significant reduction in diode turn-off losses as well as insulated-gate bipolar transistor (IGBT) turn-on losses. The hybrid modules are supplied in industry-standard 140 mm x 130 mm and 190 mm x 130 mm packages to demonstrate direct module substitution into existing inverter designs. A focus on laminated bus/capacitor-bank/module subassembly level switching performance is presented.

  6. Multi-level Expression Design Language: Requirement level (MEDL-R) system evaluation

    NASA Technical Reports Server (NTRS)

    1980-01-01

    An evaluation of the Multi-Level Expression Design Language Requirements Level (MEDL-R) system was conducted to determine whether it would be of use in the Goddard Space Flight Center Code 580 software development environment. The evaluation is based upon a study of the MEDL-R concept of requirement languages, the functions performed by MEDL-R, and the MEDL-R language syntax. Recommendations are made for changes to MEDL-R that would make it useful in the Code 580 environment.

  7. A Dual-Input–Dual-Output Z-Source Inverter

    Microsoft Academic Search

    Seyed Mohammad Dehghan; Mustafa Mohamadian; Ali Yazdian; Farhad Ashrafzadeh

    2010-01-01

    This paper presents a new z-source inverter with two AC outputs and two DC inputs. This inverter is based on the z-source inverter and nine-switch inverter. The presented inverter can control amplitude, frequency, and phase of both AC outputs and also control current of both DC inputs. Input dc voltages are boosted to the required level. Also, both outputs continue

  8. Multi-level assessment protocol (MAP) for adoption in multi-site clinical trials

    PubMed Central

    Guydish, J.; Manser, S.T.; Jessup, M.; Tajima, B.; Sears, C.; Montini, T.

    2010-01-01

    The National Institute on Drug Abuse (NIDA) Clinical Trials Network (CTN) is intended to test promising drug abuse treatment models in multi-site clinical trials, and to support adoption of new interventions into clinical practice. Using qualitative research methods we asked: How might the technology of multi-site clinical trials be modified to better support adoption of tested interventions? A total of 42 participants, representing 8 organizational levels ranging from clinic staff to clinical trial leaders, were interviewed about their role in the clinical trial, its interactions with clinics, and intervention adoption. Among eight clinics participating in the clinical trial, we found adoption of the tested intervention in one clinic only. In analysis of interview data we identified four conceptual themes which are likely to affect adoption and may be informative in future multi-site clinical trials. We offer the conclusion that planning for adoption in the early stages of protocol development will better serve the aim of integrating new interventions into practice. PMID:20890376

  9. Development of the Multi-Level Seismic Receiver (MLSR)

    SciTech Connect

    Sleefe, G.E.; Engler, B.P.; Drozda, P.M.; Franco, R.J.; Morgan, J.

    1995-02-01

    The Advanced Geophysical Technology Department (6114) and the Telemetry Technology Development Department (2664) have, in conjunction with the Oil Recovery Technology Partnership, developed a Multi-Level Seismic Receiver (MLSR) for use in crosswell seismic surveys. The MLSR was designed and evaluated with the significant support of many industry partners in the oil exploration industry. The unit was designed to record and process superior quality seismic data operating in severe borehole environments, including high temperature (up to 200{degrees}C) and static pressure (10,000 psi). This development has utilized state-of-the-art technology in transducers, data acquisition, and real-time data communication and data processing. The mechanical design of the receiver has been carefully modeled and evaluated to insure excellent signal coupling into the receiver.

  10. Development of the Multi-Level Seismic Receiver (MLSR)

    NASA Astrophysics Data System (ADS)

    Sleefe, G. E.; Engler, B. P.; Drozda, P. M.; Franco, R. J.; Morgan, Jeff

    1995-02-01

    The Advanced Geophysical Technology Department (6114) and the Telemetry Technology Development Department (2664) have, in conjunction with the Oil Recovery Technology Partnership, developed a Multi-Level Seismic Receiver (MLSR) for use in crosswell seismic surveys. The MLSR was designed and evaluated with the significant support of many industry partners in the oil exploration industry. The unit was designed to record and process superior quality seismic data operating in severe borehole environments, including high temperature (up to 200 C) and static pressure (10,000 psi). This development has utilized state-of-the-art technology in transducers, data acquisition, and real-time data communication and data processing. The mechanical design of the receiver has been carefully modeled and evaluated to insure excellent signal coupling into the receiver.

  11. Translation Levels Control Multi-Spanning Membrane Protein Expression

    PubMed Central

    Brown, Cecilia; Bostrom, Jenny; Fuh, Germaine; Lee, Chingwei V.; Huang, Arthur; Vandlen, Richard L.; Yansura, Daniel G.

    2012-01-01

    Attempts to express eukaryotic multi-spanning membrane proteins at high-levels have been generally unsuccessful. In order to investigate the cause of this limitation and gain insight into the rate limiting processes involved, we have analyzed the effect of translation levels on the expression of several human membrane proteins in Escherichia coli (E. coli). These results demonstrate that excessive translation initiation rates of membrane proteins cause a block in protein synthesis and ultimately prevent the high-level accumulation of these proteins. Moderate translation rates allow coupling of peptide synthesis and membrane targeting, resulting in a significant increase in protein expression and accumulation over time. The current study evaluates four membrane proteins, CD20 (4-transmembrane (TM) helixes), the G-protein coupled receptors (GPCRs, 7-TMs) RA1c and EG-VEGFR1, and Patched 1 (12-TMs), and demonstrates the critical role of translation initiation rates in the targeting, insertion and folding of integral membrane proteins in the E. coli membrane. PMID:22563408

  12. boolean queries Inverted index

    E-print Network

    Lu, Jianguo

    boolean queries Inverted index query processing Query optimization boolean model September 9, 2014 1 / 39 #12;boolean queries Inverted index query processing Query optimization Outline 1 boolean queries 2 Inverted index 3 query processing 4 Query optimization 2 / 39 #12;boolean queries Inverted index

  13. Verify level control criteria for multi-level cell flash memories and their applications

    NASA Astrophysics Data System (ADS)

    Kim, Yongjune; Kim, Jaehong; Kong, Jun Jin; K Vijaya Kumar, B. V.; Li, Xin

    2012-12-01

    In 1 M-bit/cell multi-level cell (MLC) flash memories, it is more difficult to guarantee the reliability of data as M increases. The reason is that an M-bit/cell MLC has 2 M states whereas a single-level cell (SLC) has only two states. Hence, compared to SLC, the margin of MLC is reduced, thereby making it sensitive to a number of degradation mechanisms such as cell-to-cell interference and charge leakage. In flash memories, distances between 2 M states can be controlled by adjusting verify levels during incremental step pulse programming (ISPP). For high data reliability, the control of verify levels in ISPP is important because the bit error rate (BER) will be affected significantly by verify levels. As M increases, the verify level control will be more important and complex. In this article, we investigate two verify level control criteria for MLC flash memories. The first criterion is to minimize the overall BER and the second criterion is to make page BERs equal. The choice between these criteria relates to flash memory architecture, bits per cell, reliability, and speed performance. Considering these factors, we will discuss the strategy of verify level control in the hybrid solid state drives (SSD) which are composed of flash memories with different number of bits per cell.

  14. NEWS VIDEO STORY SEGMENTATION USING FUSION OF MULTI-LEVEL MULTI-MODAL FEATURES IN TRECVID 2003

    E-print Network

    Chang, Shih-Fu

    NEWS VIDEO STORY SEGMENTATION USING FUSION OF MULTI-LEVEL MULTI-MODAL FEATURES IN TRECVID 2003 W In this paper, we present our new results in news video story seg- mentation and classification in the context, continuous and delta ones. We also developed several novel features related to prosody. Using the large news

  15. Harmonic analysis and FPGA implementation of SHE controlled three phase CHB 11-level inverter in MV drives using deterministic and stochastic optimization techniques.

    PubMed

    Vesapogu, Joshi Manohar; Peddakotla, Sujatha; Kuppa, Seetha Rama Anjaneyulu

    2013-01-01

    With the advancements in semiconductor technology, high power medium voltage (MV) Drives are extensively used in numerous industrial applications. Challenging technical requirements of MV Drives is to control multilevel inverter (MLI) with less Total harmonic distortion (%THD) which satisfies IEEE standard 519-1992 harmonic guidelines and less switching losses. Among all modulation control strategies for MLI, Selective harmonic elimination (SHE) technique is one of the traditionally preferred modulation control technique at fundamental switching frequency with better harmonic profile. On the other hand, the equations which are formed by SHE technique are highly non-linear in nature, may exist multiple, single or even no solution at particular modulation index (MI). However, in some MV Drive applications, it is required to operate over a range of MI. Providing analytical solutions for SHE equations during the whole range of MI from 0 to 1, has been a challenging task for researchers. In this paper, an attempt is made to solve SHE equations by using deterministic and stochastic optimization methods and comparative harmonic analysis has been carried out. An effective algorithm which minimizes %THD with less computational effort among all optimization algorithms has been presented. To validate the effectiveness of proposed MPSO technique, an experiment is carried out on a low power proto type of three phase CHB 11- level Inverter using FPGA based Xilinx's Spartan -3A DSP Controller. The experimental results proved that MPSO technique has successfully solved SHE equations over all range of MI from 0 to 1, the %THD obtained over major range of MI also satisfies IEEE 519-1992 harmonic guidelines too. PMID:24010030

  16. T. Park, et al. 1 MIT-MTL Multi-level Pattern Effects in Copper CMP

    E-print Network

    Boning, Duane S.

    T. Park, et al. 1 MIT-MTL Multi-level Pattern Effects in Copper CMP Multi-level Pattern Effects in Copper CMP T. Park, T. Tugbawa, D. Boning Massachusetts Institute of Technology http Effects in Copper CMP Copper CMP Process and Problems: Single Level I Non-Uniformity on a Single Layer

  17. Interactive fuzzy programming for multi-level linear programming problems with fuzzy parameters

    Microsoft Academic Search

    Masatoshi Sakawa; Ichiro Nishizaki; Yoshio Uemura

    2000-01-01

    This paper presents interactive fuzzy programming for multi-level linear programming problems with fuzzy parameters. In fuzzy programming for multi-level linear programming problems, recently developed by Lai et al., since the fuzzy goals are determined for both an objective function and decision variables at the upper level, undesirable solutions are produced when these fuzzy goals are inconsistent. In order to overcome

  18. Multi-level recordable disc using signal waveform modulation recording method

    NASA Astrophysics Data System (ADS)

    Pei, Jing; Pan, Longfa; Yang, Bo; Hu, Junhua

    A new kind of multi-level recordable disc is presented in this paper. By improving the recording control signal in DVD-R/RW burning process, a Multi-level disc with signal waveform modulation can be achieved. The multi-level recording method increases the recording density but also the channel noise. The optimally designed partial response maximum likelihood (PRML) equalizer is effective in recovering channel symbol, and the original error rate reach 10E-4. This kind of multi-level method can be used for the purpose such as increasing the capacity of disc, hiding data and burning disc identification information etc.

  19. Realistic mass ratio magnetic reconnection simulations with the Multi Level Multi Domain method

    NASA Astrophysics Data System (ADS)

    Innocenti, Maria Elena; Beck, Arnaud; Lapenta, Giovanni; Markidis, Stefano

    2014-05-01

    Space physics simulations with the ambition of realistically representing both ion and electron dynamics have to be able to cope with the huge scale separation between the electron and ion parameters while respecting the stability constraints of the numerical method of choice. Explicit Particle In Cell (PIC) simulations with realistic mass ratio are limited in the size of the problems they can tackle by the restrictive stability constraints of the explicit method (Birdsall and Langdon, 2004). Many alternatives are available to reduce such computation costs. Reduced mass ratios can be used, with the caveats highlighted in Bret and Dieckmann (2010). Fully implicit (Chen et al., 2011a; Markidis and Lapenta, 2011) or semi implicit (Vu and Brackbill, 1992; Lapenta et al., 2006; Cohen et al., 1989) methods can bypass the strict stability constraints of explicit PIC codes. Adaptive Mesh Refinement (AMR) techniques (Vay et al., 2004; Fujimoto and Sydora, 2008) can be employed to change locally the simulation resolution. We focus here on the Multi Level Multi Domain (MLMD) method introduced in Innocenti et al. (2013) and Beck et al. (2013). The method combines the advantages of implicit algorithms and adaptivity. Two levels are fully simulated with fields and particles. The so called "refined level" simulates a fraction of the "coarse level" with a resolution RF times bigger than the coarse level resolution, where RF is the Refinement Factor between the levels. This method is particularly suitable for magnetic reconnection simulations (Biskamp, 2005), where the characteristic Ion and Electron Diffusion Regions (IDR and EDR) develop at the ion and electron scales respectively (Daughton et al., 2006). In Innocenti et al. (2013) we showed that basic wave and instability processes are correctly reproduced by MLMD simulations. In Beck et al. (2013) we applied the technique to plasma expansion and magnetic reconnection problems. We showed that notable computational time savings can be achieved. More importantly, we were able to correctly reproduce EDR features, such as the inversion layer of the electric field observed in Chen et al. (2011b), with a MLMD simulation at a significantly lower cost. Here, we present recent results on EDR dynamics achieved with the MLMD method and a realistic mass ratio.

  20. Comparison of Multiple Carrier Disposition PWM Techniques Applied for Multi-Level Shunt Active Filter

    NASA Astrophysics Data System (ADS)

    Kathalingam, Sebasthi Rani; Karantharaj, Porkumaran

    2012-07-01

    This work presents the simulation of a shunt active filter using seven-level cascaded inverter. The ultimate objective is to bring out the influence of multiple carrier level shifted PWM techniques on the performance of a shunt active filter. Classical disposition PWM techniques such as PD, POD and APOD have been used to generate the gating signals for the inverter active switches. A comparison is presented to substantiate the effect of these techniques in filtering. The comparison is made from the perspective of reduction in THD of source currents after filtering. For compensation current extraction synchronous detection method has been used. The harmonic reduction is achieved in source currents as well as source voltages.

  1. Hybrid Cascaded Multilevel Inverter with PWM Control Method

    E-print Network

    Tolbert, Leon M.

    for each phase) and H-bridge in series with each inverter leg. It can use only a single DC power source carrier- based PWM method is used to produce a five-level phase voltage. The inverter can be used function of the multilevel inverter is to synthesize a desired high voltage from several levels of dc

  2. Design of a Multi-Level/Analog Ferroelectric Memory Device

    NASA Technical Reports Server (NTRS)

    MacLeod, Todd C.; Phillips, Thomas A.; Ho, Fat D.

    2006-01-01

    Increasing the memory density and utilizing the dove1 characteristics of ferroelectric devices is important in making ferroelectric memory devices more desirable to the consumer. This paper describes a design that allows multiple levels to be stored in a ferroelectric based memory cell. It can be used to store multiple bits or analog values in a high speed nonvolatile memory. The design utilizes the hysteresis characteristic of ferroelectric transistors to store an analog value in the memory cell. The design also compensates for the decay of the polarization of the ferroelectric material over time. This is done by utilizing a pair of ferroelectric transistors to store the data. One transistor is used as a reference to determine the amount of decay that has occurred since the pair was programmed. The second transistor stores the analog value as a polarization value between zero and saturated. The design allows digital data to be stored as multiple bits in each memory cell. The number of bits per cell that can be stored will vary with the decay rate of the ferroelectric transistors and the repeatability of polarization between transistors. It is predicted that each memory cell may be able to store 8 bits or more. The design is based on data taken from actual ferroelectric transistors. Although the circuit has not been fabricated, a prototype circuit is now under construction. The design of this circuit is different than multi-level FLASH or silicon transistor circuits. The differences between these types of circuits are described in this paper. This memory design will be useful because it allows higher memory density, compensates for the environmental and ferroelectric aging processes, allows analog values to be directly stored in memory, compensates for the thermal and radiation environments associated with space operations, and relies only on existing technologies.

  3. MODEL AND SIMULATION OF MULTI-LEVEL EMERGENCE Gregory Beurier

    E-print Network

    Simonin, Olivier -Département Informatique, Institut National des Sciences Appliquées de Lyon

    ] or biological [7] models). In this paper we adopt a multi-agent definition, which covers different domains (such and natural complex systems. Key-words: Emergence, Multi-Agent Systems, Reactive Agents, Simulation they are biological, physical, informational, software, etc. In artificial ones this phenomenon must be controlled

  4. Poster Abstract: Wireless Link Simulations using Multi-level Markov Models

    E-print Network

    Cerpa, Alberto E.

    communication over short and long time-scales and over distance. In this paper, we pro- pose a novel multilevel the Multi-level Markov (M&M) model, for modeling the long and short time scale behavior of links in wirelessPoster Abstract: Wireless Link Simulations using Multi-level Markov Models Ankur U. Kamthe, Miguel

  5. Metric Forensics: A Multi-Level Approach for Mining Volatile Graphs

    E-print Network

    Faloutsos, Christos

    Metric Forensics: A Multi-Level Approach for Mining Volatile Graphs Keith Henderson Lawrence are required. An example that has drawn significant research interest is the cyber-security domain, where. METRICFOREN- SICS combines a multi-level "drill down" approach, a collec- tion of user-selected graph metrics

  6. A multi-level assessment methodology for determining the potential for groundwater contamination by pesticides

    Microsoft Academic Search

    A. S. Crowe; W. G. Booty

    1995-01-01

    A multi-level pesticide assessment methodology has been developed to permit regulatory personnel to undertake a variety of assessments on the potential for pesticide used in agricultural areas to contaminate the groundwater regime at an increasingly detailed geographical scale of investigation. A multi-level approach accounts for a variety of assessment objectives and detail required in the assessment, the restrictions on the

  7. Ports in multi-level maritime networks: evidence from the Atlantic (1996-2006)

    E-print Network

    Paris-Sud XI, Université de

    Ports in multi-level maritime networks: evidence from the Atlantic (1996-2006) Journal of Transport.jtrangeo.2010.03.005 #12;Ports in multi-level maritime networks: evidence from the Atlantic (1996-2006) Abstract While maritime transport ensures about 90% of world trade volumes, it has not yet attracted as much

  8. Multi-level annotation in the Emu speech database management system

    E-print Network

    Harrington, Jonathan

    Multi-level annotation in the Emu speech database management system Steve Cassidy a,*, Jonathan August 2000 Abstract Researchers in various ®elds, from acoustic phonetics to child language development, is a general purpose speech database management system which supports complex multi- level annotations. Emu can

  9. Ph. D. Dissertation Multi-level Analysis on Structures and Dynamics of

    E-print Network

    Moon, Sue B.

    Ph. D. Dissertation Multi-level Analysis on Structures and Dynamics of Online Social Networks and Dynamics of Online Social Networks #12;Multi-level Analysis on Structures and Dynamics of Online Social on Structures and Dynamics of Online Social Networks. . Department of Computer Science . 2011. 125p. Advisor

  10. Conceptualising the perceived service quality of public utility services: A multi-level, multi-dimensional model

    Microsoft Academic Search

    Changhong Bai; Fujun Lai; Ye Chen; Joe Hutchinson

    2008-01-01

    Based on the data relevant to four public utility services (water, natural gas, electricity and thermoelectricity) collected by a personally administered on-site survey, the authors develop a model to assess the perceived service quality of public utility services. In the model, the perceived service quality of public utility services has a multi-level, multi-dimensional structure with three primary dimensions: outcome, environment

  11. Cascade Multilevel Inverters for Utility Applications

    SciTech Connect

    Peng, F.Z., McKeever, J.W., Adams, D.J.

    1997-12-31

    Cascade multilevel inverters have been developed by the authors for utility applications. A cascade M-level inverter consists of (M-1)/2 H- bridges in which each bridge has its own separate dc source. The new inverter: (1) can generate almost sinusoidal waveform voltage while only switching one time per fundamental cycle, (2) can eliminate transformers of multipulse inverters used in conventional utility interfaces and static var compensators, and (3) makes possible direct parallel or series connection to medium- and high-voltage power systems without any transformers. In other words, the cascade inverter is much more efficient and suitable for utility applications than traditional multipulse and pulse width modulation (PWM) inverters. The authors have experimentally demonstrated the superiority of the new inverter for reactive power (var) and harmonic compensation. This paper will summarize features,feasibility, and control schemes of the cascade inverter for utility applications including utility interface of renewable energy, voltage regulation, var compensation, and harmonic filtering in power systems.Analytical, simulated, and experimental results demonstrate the superiority of the new inverters.

  12. Green Power Inverter Prvningsrapport

    E-print Network

    Green Power Inverter Prøvningsrapport SolenergiCentret Søren Poulsen Ivan Katic Oktober 2004 #12;Green Power Inverter målerapport.doc SolenergiCentret - 04-03-2005 2 Forord Nærværende rapport indeholder Teknologisk Instituts bidrag til målinger i forbindelse med PSO projektet "Green Power Inverter

  13. A Cascade Multilevel Inverter Using a Single DC Source

    E-print Network

    Tolbert, Leon M.

    A Cascade Multilevel Inverter Using a Single DC Source Zhong Du1, Leon M. Tolbert2 3, John N inverter can be implemented using only a single DC power source and capacitors. A standard cascade multilevel inverter requires DC sources for 2 + 1 levels. Without requiring transformers, the scheme proposed

  14. Energy-Efficient Airtime Allocation in Multi-Rate Multi-Power-Level Wireless LANs

    E-print Network

    Qiao, Daji

    @iastate.edu kgshin@eecs.umich.edu ABSTRACT This paper considers the energy-conservation problem in multi-rate multi stations, we introduce a new fairness notion, called energy- conservation fairness, in contrast that the combined airtime and energy-conservation fairness is achieved. Our simu- lation results show that, when

  15. A generalized multilevel inverter topology with self voltage balancing

    Microsoft Academic Search

    Fang Zheng Peng

    2001-01-01

    Multilevel power converters that provide more than two levels of voltage to achieve smoother and less distorted AC-to-DC, DC-to-AC, and DC-to-DC power conversion, have attracted many contributors. This paper presents a generalized multilevel inverter (converter) topology with self voltage balancing. The existing multilevel inverters such as diode-clamped and capacitor-clamped multilevel inverters can be derived from the generalized inverter topology. Moreover,

  16. A multi-level DRAM with fast read and low power consumption

    Microsoft Academic Search

    Bo Liu; James F Frenzel; Richard B Wells

    2005-01-01

    In this paper, we present a new, multi-level DRAM design, which can store 3 voltage levels (0, Vcc, and Vcc\\/2) in a single memory cell. This multi-level DRAM requires no special reference voltage and simplifies design of the peripheral circuits. Coding algorithms may be used to provide binary data immediately after first read, with the second read operation providing a

  17. MultiLevel Modeling of Dyadic Data in Sport Sciences: Conceptual, Statistical, and Practical Issues

    Microsoft Academic Search

    Patrick Gaudreau; Marie-Claude Fecteau; Stéphane Perreault

    2010-01-01

    The goal of this article is to present a series of conceptual, statistical, and practical issues in the modeling of multi-level dyadic data. Distinctions are made between distinguishable and undistinguishable dyads and several types of independent variables modeled at the dyadic level of analysis. Multi-level modeling equations are explained in a non-technical manner. A database of 66 athletes regrouped in

  18. Optimization of multi-photon event discrimination levels using Poisson statistics.

    PubMed

    Soukka, Juri; Virkki, Arho; Hänninen, Pekka; Soini, Juhani

    2004-01-12

    In applications where random multi-photon events must be distinguishable from the background, detection of the signals must be based on either analog current measurement or photon counting and multi-level discrimination of single and multi-photon events. In this paper a novel method for optimizing photomultiplier (PMT) pulse discrimination levels in single- and multi-photon counting is demonstrated. This calibration method is based on detection of photon events in coincidence to short laser pulses. The procedure takes advantage of Poisson statistics of single- and mult-iphoton signals and it is applicable to automatic calibration of photon counting devices on production line. Results obtained with a channel photomultiplier (CPM) are shown. By use of three parallel discriminators and setting the discriminator levels according to the described method resulted in a linear response over wide range of random single- and multi-photon signals. PMID:19471514

  19. Parallel operation control technique of voltage source inverters in UPS

    Microsoft Academic Search

    Duan Shanxu; Meng Yu; Xiong Jian; Kang Yong; Chen Jian

    1999-01-01

    The control technique of a parallel operation system of voltage source inverters with other inverters or with utility source has been applied in many fields, especially in uninterruptible power supply (UPS). The multi-module UPS can flexibly implement expansion of power system capacities. Furthermore, it can be used to build up a parallel redundant system in order to improve the reliability

  20. PHIL Inverter Test Report: Analysis of High-Penetration Levels of PV into the Distribution Grid in California, March 12 - March 16, 2012

    SciTech Connect

    Kromer, M.

    2013-06-01

    This report describes power hardware-in-the-loop simulation testing of a 500 kW Satcon photovoltaic inverter, conducted at the Center for Advanced Power Systems at Florida State University from March 12th through March 16th, 2012. Testing was led by a team from the National Renewable Energy Laboratory. The report reviews the results of data captured during the course of testing. The tests were used to demonstrate operation of and gather data from the inverter in a simulated operational environment. Testing demonstrated the ability of the inverter to operate in either a Power Factor Control Mode or a Reactive Power Command Mode, and to respond to real power limits.

  1. Architecture-level Thermal Behavioral Characterization For Multi-Core Microprocessors

    E-print Network

    Tan, Sheldon X.-D.

    Architecture-level Thermal Behavioral Characterization For Multi-Core Microprocessors Duo Li Dept-performance multi-core microprocessor design. We propose a new approach, called ThermPOF, to build the thermal-space form. Experimental results on a practi- cal quad-core microprocessor show that generated thermal

  2. A Multi-level Constraint-based Controller for the Dynamo98 Robot Soccer Team

    E-print Network

    Mackworth, Alan K.

    A Multi-level Constraint-based Controller for the Dynamo98 Robot Soccer Team Yu Zhang and Alan K solvers that solve constraints in real-time. A controller for our new softbot soccer team, UBC Dynamo98 and implementing controllers for robots in multi-agent real-time environments. 1 Background and Introduction Soccer

  3. The incidence of death among low-risk populations: a multi-level analysis 

    E-print Network

    Lewinski, Christi Nicole

    2007-09-17

    This study utilized a multi-level model to examine the impact of religion as an occupation on mortality. Death certificate data were used to examine clergy mortality and compares them to census categorized professionals, counseling professionals...

  4. DDSS: Dynamic Dedicated Servers Scheduling for Multi Priority Level Classes in Cloud Computing

    E-print Network

    Atiquzzaman, Mohammed

    DDSS: Dynamic Dedicated Servers Scheduling for Multi Priority Level Classes in Cloud Computing policy have increased the usage of cloud computing over traditional computing. Cloud computing should service providers build efficient cloud computing service architectures through considering different

  5. A New Modulation Method for Hexagram Inverter

    Microsoft Academic Search

    Jun Wen; Keyue Ma Smedley

    2008-01-01

    Recently, Hexagram inverter has been proposed for medium-voltage variable speed drive systems. It is composed of six interconnected three-phase two-level voltage source inverters, and has the advantages of modular and symmetrical structure, even and much reduced voltage stress, low dc energy storage requirement, and easy control with well-developed two-level control techniques, and therefore, has the potential for future high power

  6. MultiLevel Fuzzy Score Fusion for Client Specific Linear Discriminant Analysis Based Face Authentication System

    Microsoft Academic Search

    Babak Rezaei Rowshan; Marzuki Bin Khalid; Rubiyah Yusof

    2008-01-01

    A client specific linear discriminant analysis (CSLDA) based face authentication system has been developed with multi-level fuzzy score fusion. The CSLDA method provides two measures for authentication: distance to the client (Client Score) and distance to the mean of impostors (Impostor Score). A two-level multi-sample score fusion method has been proposed. A fuzzy inference module has also been developed to

  7. The Problematique of Community-Based Conservation in a MultiLevel World

    Microsoft Academic Search

    Fikret Berkes

    Community-based resource management or community-based conservation is not just about communities. It is about governance that starts from the ground up and involves multi-level interactions. Complexities of this multi-level world create problems but also provide opportunities to combine conservation with development. I unpack the problematique of community-based conservation and deal with four aspects of it. The first is the inability

  8. Don't Care Minimization of MultiLevel Sequential Logic Networks

    Microsoft Academic Search

    Bill Lin; Hervé J. Touati; A. Richard Newton

    1990-01-01

    The authors address the problem of computing sequential don't cares that arise in the context of multi-level sequential networks and their use in sequential logic synthesis. The key to their approach is the use of binary decision diagram (BDD)-based implicit state space enumeration techniques and multi-level combinational simplification procedures. Using the algorithms described, exact sequential don't care sets for circuits

  9. Improving Memory Hierarchy Performance Through Combined Loop Interchange and Multi-Level Fusion

    E-print Network

    Yi, Qing

    Improving Memory Hierarchy Performance Through Combined Loop Interchange and Multi-Level Fusion that access similar sets of data. Typically, it is applied to loops at the same level after loop interchange, resulting in a memory hierarchy. The data access latency to a higher level of the memory hierarchy is often

  10. Mesoscopic to universal crossover of transmission phase of multi-level quantum dots

    Microsoft Academic Search

    C. Karrasch; T. Hecht; A. Weichselbaum; Y. Oreg; J. von Delft; V. Meden

    Transmission phasemeasurements of many-electron quantum dots (small mean level spacing ?) revealed universal phase lapses bybetween consecutive resonances. In contrast, for dots with only a few electrons (large ?), the appearance or not of a phase lapse depends on the dot parameters. We show that a model of a multi-level quantum dot with local Coulomb interactions and arbitrary level-lead couplings

  11. Invertible Darboux Transformations

    E-print Network

    Ekaterina Shemyakova

    2013-01-04

    For operators of many different kinds it has been proved that (generalized) Darboux transformations can be built using so called Wronskian formulae. Such Darboux transformations are not invertible in the sense that the corresponding mappings of the operator kernels are not invertible. The only known invertible ones were Laplace transformations (and their compositions), which are special cases of Darboux transformations for hyperbolic bivariate operators of order 2. In the present paper we find a criteria for a bivariate linear partial differential operator of an arbitrary order d to have an invertible Darboux transformation. We show that Wronkian formulae may fail in some cases, and find sufficient conditions for such formulae to work.

  12. 49 CFR Figure 2b to Subpart B of... - Example of an Intermediate Level Seating Area of a Multi-Level Car Complying With Window Location...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...Intermediate Level Seating Area of a Multi-Level Car Complying With Window Location Requirements-§§ 238.113 and 238.114 2B...Intermediate Level Seating Area of a Multi-Level Car Complying With Window Location Requirements—§§ 238.113 and 238.114...

  13. 49 CFR Figure 2b to Subpart B of... - Example of an Intermediate Level Seating Area of a Multi-Level Car Complying With Window Location...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...Intermediate Level Seating Area of a Multi-Level Car Complying With Window Location Requirements-§§ 238.113 and 238.114 2B...Intermediate Level Seating Area of a Multi-Level Car Complying With Window Location Requirements—§§ 238.113 and 238.114...

  14. 49 CFR Figure 2b to Subpart B of... - Example of an Intermediate Level Seating Area of a Multi-Level Car Complying With Window Location...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...Intermediate Level Seating Area of a Multi-Level Car Complying With Window Location Requirements-§§ 238.113 and 238.114 2B...Intermediate Level Seating Area of a Multi-Level Car Complying With Window Location Requirements—§§ 238.113 and 238.114...

  15. 49 CFR Figure 2a to Subpart B of... - Example of an Intermediate Level Seating Area of a Multi-Level Car Complying With Window Location...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...Intermediate Level Seating Area of a Multi-Level Car Complying With Window Location Requirements-§§ 238.113 and 238.114 2A...Intermediate Level Seating Area of a Multi-Level Car Complying With Window Location Requirements—§§ 238.113 and 238.114...

  16. 49 CFR Figure 2a to Subpart B of... - Example of an Intermediate Level Seating Area of a Multi-Level Car Complying With Window Location...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...Intermediate Level Seating Area of a Multi-Level Car Complying With Window Location Requirements-§§ 238.113 and 238.114 2A...Intermediate Level Seating Area of a Multi-Level Car Complying With Window Location Requirements—§§ 238.113 and 238.114...

  17. 49 CFR Figure 2a to Subpart B of... - Example of an Intermediate Level Seating Area of a Multi-Level Car Complying With Window Location...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...Intermediate Level Seating Area of a Multi-Level Car Complying With Window Location Requirements-§§ 238.113 and 238.114 2A...Intermediate Level Seating Area of a Multi-Level Car Complying With Window Location Requirements—§§ 238.113 and 238.114...

  18. 49 CFR Figure 2b to Subpart B of... - Example of an Intermediate Level Seating Area of a Multi-Level Car Complying With Window Location...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...Intermediate Level Seating Area of a Multi-Level Car Complying With Window Location Requirements-§§ 238.113 and 238.114 2B...Intermediate Level Seating Area of a Multi-Level Car Complying With Window Location Requirements—§§ 238.113 and 238.114...

  19. 49 CFR Figure 2b to Subpart B of... - Example of an Intermediate Level Seating Area of a Multi-Level Car Complying With Window Location...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...Intermediate Level Seating Area of a Multi-Level Car Complying With Window Location Requirements-§§ 238.113 and 238.114 2B...Intermediate Level Seating Area of a Multi-Level Car Complying With Window Location Requirements—§§ 238.113 and 238.114...

  20. 49 CFR Figure 2a to Subpart B of... - Example of an Intermediate Level Seating Area of a Multi-Level Car Complying With Window Location...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...Intermediate Level Seating Area of a Multi-Level Car Complying With Window Location Requirements-§§ 238.113 and 238.114 2A...Intermediate Level Seating Area of a Multi-Level Car Complying With Window Location Requirements—§§ 238.113 and 238.114...

  1. 49 CFR Figure 2a to Subpart B of... - Example of an Intermediate Level Seating Area of a Multi-Level Car Complying With Window Location...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...Intermediate Level Seating Area of a Multi-Level Car Complying With Window Location Requirements-§§ 238.113 and 238.114 2A...Intermediate Level Seating Area of a Multi-Level Car Complying With Window Location Requirements—§§ 238.113 and 238.114...

  2. Design, implementation, and verification of a multipurpose, flexible, three-phase back-to-back voltage-source inverter

    E-print Network

    Chai, Elaina T

    2014-01-01

    In this thesis, I designed, implemented, and verified a multi-purpose,three-phase back-to- back voltage source inverter for grid connected applications. This inverter features extensive hardware protection, opto-isolation ...

  3. Rule-based multi-level modeling of cell biological systems

    PubMed Central

    2011-01-01

    Background Proteins, individual cells, and cell populations denote different levels of an organizational hierarchy, each of which with its own dynamics. Multi-level modeling is concerned with describing a system at these different levels and relating their dynamics. Rule-based modeling has increasingly attracted attention due to enabling a concise and compact description of biochemical systems. In addition, it allows different methods for model analysis, since more than one semantics can be defined for the same syntax. Results Multi-level modeling implies the hierarchical nesting of model entities and explicit support for downward and upward causation between different levels. Concepts to support multi-level modeling in a rule-based language are identified. To those belong rule schemata, hierarchical nesting of species, assigning attributes and solutions to species at each level and preserving content of nested species while applying rules. Further necessities are the ability to apply rules and flexibly define reaction rate kinetics and constraints on nested species as well as species that are nested within others. An example model is presented that analyses the interplay of an intracellular control circuit with states at cell level, its relation to cell division, and connections to intercellular communication within a population of cells. The example is described in ML-Rules - a rule-based multi-level approach that has been realized within the plug-in-based modeling and simulation framework JAMES II. Conclusions Rule-based languages are a suitable starting point for developing a concise and compact language for multi-level modeling of cell biological systems. The combination of nesting species, assigning attributes, and constraining reactions according to these attributes is crucial in achieving the desired expressiveness. Rule schemata allow a concise and compact description of complex models. As a result, the presented approach facilitates developing and maintaining multi-level models that, for instance, interrelate intracellular and intercellular dynamics. PMID:22005019

  4. Switching Characteristics of Ferroelectric Transistor Inverters

    NASA Technical Reports Server (NTRS)

    Laws, Crystal; Mitchell, Coey; MacLeod, Todd C.; Ho, Fat D.

    2010-01-01

    This paper presents the switching characteristics of an inverter circuit using a ferroelectric field effect transistor, FeFET. The propagation delay time characteristics, phl and plh are presented along with the output voltage rise and fall times, rise and fall. The propagation delay is the time-delay between the V50% transitions of the input and output voltages. The rise and fall times are the times required for the output voltages to transition between the voltage levels V10% and V90%. Comparisons are made between the MOSFET inverter and the ferroelectric transistor inverter.

  5. Outline Inverted File Building Compression for Inverted Files Building and Compression Techniques for Inverted

    E-print Network

    Barreiro, Alvaro

    Outline Inverted File Building Compression for Inverted Files Building and Compression Techniques for Inverted Files Roi Blanco Dpt. Computing Science, University of A Coruna December 13, 2005 Roi Blanco Building and Compression Techniques for Inverted Files #12;Outline Inverted File Building Compression

  6. Multi-level learning: improving the prediction of protein, domain and residue interactions by allowing information flow between levels

    PubMed Central

    Yip, Kevin Y; Kim, Philip M; McDermott, Drew; Gerstein, Mark

    2009-01-01

    Background Proteins interact through specific binding interfaces that contain many residues in domains. Protein interactions thus occur on three different levels of a concept hierarchy: whole-proteins, domains, and residues. Each level offers a distinct and complementary set of features for computationally predicting interactions, including functional genomic features of whole proteins, evolutionary features of domain families and physical-chemical features of individual residues. The predictions at each level could benefit from using the features at all three levels. However, it is not trivial as the features are provided at different granularity. Results To link up the predictions at the three levels, we propose a multi-level machine-learning framework that allows for explicit information flow between the levels. We demonstrate, using representative yeast interaction networks, that our algorithm is able to utilize complementary feature sets to make more accurate predictions at the three levels than when the three problems are approached independently. To facilitate application of our multi-level learning framework, we discuss three key aspects of multi-level learning and the corresponding design choices that we have made in the implementation of a concrete learning algorithm. 1) Architecture of information flow: we show the greater flexibility of bidirectional flow over independent levels and unidirectional flow; 2) Coupling mechanism of the different levels: We show how this can be accomplished via augmenting the training sets at each level, and discuss the prevention of error propagation between different levels by means of soft coupling; 3) Sparseness of data: We show that the multi-level framework compounds data sparsity issues, and discuss how this can be dealt with by building local models in information-rich parts of the data. Our proof-of-concept learning algorithm demonstrates the advantage of combining levels, and opens up opportunities for further research. Availability The software and a readme file can be downloaded at . The programs are written in Java, and can be run on any platform with Java 1.4 or higher and Apache Ant 1.7.0 or higher installed. The software can be used without a license. PMID:19656385

  7. Target identification using relative level in multi-talker listening.

    PubMed

    Kitterick, Pádraig T; Clarke, Emmet; O'Shea, Charlotte; Seymour, Josephine; Summerfield, A Quentin

    2013-05-01

    Previous studies have suggested that listeners can identify words spoken by a target talker amidst competing talkers if they are distinguished by their spatial location or vocal characteristics. This "direct" identification of individual words is distinct from an "indirect" identification based on an association with other words (call-signs) that uniquely label the target. The present study assessed listeners' ability to use differences in presentation level between a target and overlapping maskers to identify target words. A new sentence was spoken every 800?ms by an unpredictable talker from an unpredictable location. Listeners reported color and number words in a target sentence distinguished by a unique call-sign. When masker levels were fixed, target words could be identified directly based on their relative level. Speech-reception thresholds (SRTs) were low (-12.9 dB) and were raised by 5 dB when direct identification was disrupted by randomizing masker levels. Thus, direct identification is possible using relative level. The underlying psychometric functions were monotonic even when relative level was a reliable cue. In a further experiment, indirect identification was prevented by removing the unique call-sign cue. SRTs did not change provided that other cues were available to identify target words directly. Thus, direct identification is possible without indirect identification. PMID:23654395

  8. Multi-level functionality of social media in the aftermath of the Great East Japan Earthquake.

    PubMed

    Jung, Joo-Young; Moro, Munehito

    2014-07-01

    This study examines the multi-level functionalities of social media in the aftermath of the Great East Japan Earthquake of 11 March 2011. Based on a conceptual model of multi-level story flows of social media (Jung and Moro, 2012), the study analyses the multiple functionalities that were ascribed to social media by individuals, organisations, and macro-level social systems (government and the mass media) after the earthquake. Based on survey data, a review of Twitter timelines and secondary sources, the authors derive five functionalities of social media: interpersonal communications with others (micro level); channels for local governments; organisations and local media (meso level); channels for mass media (macro level); information sharing and gathering (cross level); and direct channels between micro-/meso- and macro-level agents. The study sheds light on the future potential of social media in disaster situations and suggests how to design an effective communication network to prepare for emergency situations. PMID:24905811

  9. Trans-Z-source inverters

    Microsoft Academic Search

    Wei Qian; Fang Zheng Peng; Honnyong Cha

    2010-01-01

    This paper extends the impedance-source (Z-source) inverters concept to the transformer based Z-source (trans-Z-source) inverters. The original Z-source inverter (ZSI) employs an impedance network of two inductors and two capacitors connected in a special arrangement to interface the dc source and the inverter bridge. It has overcome the conceptual limitations of the traditional voltage-source inverter and the current-source inverter. In

  10. Integrated Inverter And Battery Charger

    NASA Technical Reports Server (NTRS)

    Rippel, Wally E.

    1988-01-01

    Circuit combines functions of dc-to-ac inversion (for driving ac motor in battery-powered vehicle) and ac-to-dc conversion (for charging battery from ac line when vehicle not in use). Automatically adapts to either mode. Design of integrated inverter/charger eliminates need for duplicate components, saves space, reduces weight and cost of vehicle. Advantages in other applications : load-leveling systems, standby ac power systems, and uninterruptible power supplies.

  11. Multi-leveled objects: color as a case study

    PubMed Central

    Albertazzi, Liliana; Poli, Roberto

    2014-01-01

    The paper presents color as a case study for the analysis of phenomena that pertain to several levels of reality and are typically framed by different sciences and disciplines. Color, in fact, is studied by physics, biology, phenomenology, and esthetics, among others. Our thesis is that color is a different entity for each level of reality, and that for this reason color generates different observables in the epistemologies of the different sciences. By analyzing color as a paradigmatic case of an entity naturally spreading over different levels of reality, the paper raises the question as to whether making explicit the usually implicit ontological assumptions embedded within the different observables exploited by the different sciences may eventually clarify some of the difficulties of developing a comprehensive theory of color. PMID:25071616

  12. Object-level fusion and confidence management in a multi-sensor pedestrian tracking system

    E-print Network

    Paris-Sud XI, Université de

    Object-level fusion and confidence management in a multi-sensor pedestrian tracking system Fadi-sensor data fusion and more generally the multiplication of data sources in order to obtain more reliable the object level fusion by tracking method. Section III described the state models used to filter

  13. Using multi sensor data fusion for level estimation in a separator

    Microsoft Academic Search

    Nils-Olav Skeie; Saba Mylvaganam; Bernt Lie

    2006-01-01

    A data driven model is developed to be used as a soft sensor to predict the liquid and interface levels in an oil\\/water separator. The methodology uses a set of absolute pressure sensors together with multi sensor data fusion for estimation of the levels. Experimental results are provided for model validation.

  14. Infrastructure for multi-level secure service-oriented architecture (MLS-SOA)

    Microsoft Academic Search

    Jim Luo; Myong Kang

    2010-01-01

    Service-oriented architecture (SOA) is the premier application framework for integrating complex heterogeneous computing systems in business and government. To utilize SOA in sensitive military systems, however, the issue of multi-level security (MLS) must be addressed. MLS requirements call for strict separation and limit interaction between classification levels. However, many Web services and resources reside in the Low domains. Support services

  15. Readable English for Hearing-Impaired Students: Multi-Level Guidelines for Linguistically Controlled Reading Materials.

    ERIC Educational Resources Information Center

    Decker, Nan; And Others

    Developed by the Multi-level Captioning Project, the manual provides guidelines for linguistically controlling reading materials for the deaf. An introduction describes the three proposed reading levels based on difficulty of vocabulary, syntax, and inference. Chapter 1, on vocabulary, considers word list sources, guidelines for controlling…

  16. Multi-level Gevrey solutions of singularly perturbed linear partial differential equations

    E-print Network

    Multi-level Gevrey solutions of singularly perturbed linear partial differential equations A Abstract We study the asymptotic behavior of the solutions related to a family of singularly perturbed-Sibuya theorem in several Gevrey levels. Key words: Linear partial differential equations, singular perturbations

  17. A hybrid multi-model approach to river level forecasting

    Microsoft Academic Search

    LINDA SEE; STAN OPENSHAW

    2001-01-01

    This paper presents four different approaches for integrating conventional and AI-based forecasting models to provide a hybridized solution to the continuous river level and flood prediction problem. Individual forecasting models were developed on a stand alone basis using historical time series data from the River Ouse in northern England. These include a hybrid neural network, a simple rule-based fuzzy logic

  18. Multi-level response of the yeast genome to glucose

    PubMed Central

    Geladé, Ruud; Van de Velde, Sam; Van Dijck, Patrick; Thevelein, Johan M

    2003-01-01

    The yeast Saccharomyces cerevisiae shows a great variety of cellular responses to glucose via several glucose-sensing and signaling pathways. Recent microarray analysis has revealed multiple levels of genomic sensitivity to glucose and highlighted the power of genome-wide analysis to detect cellular responses to minute environmental changes. PMID:14611650

  19. HARPA: A hierarchical multi-level hardware description language

    Microsoft Academic Search

    Pedro M. B. Veiga

    1984-01-01

    In this paper, a new hardware description language -HARPA- is presented which was specially designed to permit the description of hierarchically structured digital systems at different levels of abstraction. The system building modules can be represented in terms of their structure, their behavior or a combination of both, as appropriate. A set of data types is provided which is adequate

  20. A multi level control architecture for a pneumatic robotic leg

    Microsoft Academic Search

    Giovanni Muscato; Giacomo Spampinato

    2005-01-01

    The paper describes the control architecture and the motion strategy of a five degrees of freedom robotic leg. The prototype realized is pneumatically actuated, so the control strategy is specifically designed in order to ensure a proper stability during the motion. The control architecture is composed of a three level feedback loop that allows a three dimensional trajectory generation, directly

  1. Relaxation dynamics of multi-level tunneling systems

    Microsoft Academic Search

    Peter Neu; Andreas Heuer

    1996-01-01

    A quantum mechanical treatment of an asymmetric double-well potential (DWP)\\u000ainteracting with a heat bath is presented for circumstances where the\\u000acontribution of higher vibrational levels to the relaxation dynamics cannot be\\u000aexcluded from consideration. The deep quantum limit characterized by a discrete\\u000aenergy spectrum near the barrier top is considered. The investigation is\\u000amotivated by simulations on a computer

  2. MultiLevel Parallelism for the Cardiac Bidomain Equations

    Microsoft Academic Search

    Carolina Ribeiro Xavier; Rafael Sachetto Oliveira; Vinicius Da Fonseca Vieira; Rodrigo Weber Dos Santos; Wagner Meira Jr.

    2009-01-01

    Cardiovascular diseases are associated with high mortality rates in the globe. The development of new drugs, new medical equipment\\u000a and non-invasive techniques for the heart demand multidisciplinary efforts towards the characterization of cardiac anatomy\\u000a and function from the molecular to the organ level. Computational modeling has demonstrated to be a useful tool for the investigation\\u000a and comprehension of the complex

  3. Multi-level damage detection with nonlinear ultrasonic methods

    NASA Astrophysics Data System (ADS)

    Matlack, Kathryn H.; Kim, Jin-Yeon; Jacobs, Laurence J.; Qu, Jianmin

    2013-01-01

    The nonlinear ultrasonic method of second harmonic generation is used to detect multiple levels of damage on a single specimen. There is a breadth of research in the literature that measures the second harmonic and the resulting nonlinear parameter to monitor increasing amounts of uniform damage, but for this method to be applicable as an in situ technique, it must be able to scan an area of a structure with varying amounts of damage over a region. To investigate this, an aluminum alloy sample is shot-peened to two intensity levels along its length, to produce different sections of cold work and residual stress as a function of spatial location. Previous research has shown that the residual stress and cold work introduced in a material from shot peening causes an increase in the nonlinear parameter. Rayleigh waves are generated in the sample and the first and second harmonic amplitudes are measured at increasing propagation distances that encompass an undamaged section and two sections, each with different levels of shot peening. Results show that the nonlinear parameter increases as the Rayleigh wedge sensor is scanned over the shot peening sections.

  4. Multi-level 3D implementation of thermo-pneumatic pumping on centrifugal microfluidic CD platforms.

    PubMed

    Thio, Tzer Hwai Gilbert; Ibrahim, Fatimah; Al-Faqheri, Wisam; Soin, Norhayati; Abdul Kahar, Maria Kahar Bador; Madou, Marc

    2013-01-01

    Thermo-pneumatic (TP) pumping is a method employing the principle of expanding heated air to transfer fluids back towards the CD center on the centrifugal microfluidic CD platform. While the TP features are easy to fabricate as no moving parts are involved, it consumes extra real estate on the CD, and because heating is involved, it introduces unnecessary heating to the fluids on the CD. To overcome these limitations, we introduce a multi-level 3D approach and implement forced convection heating. In a multi-level 3D CD, the TP features are relocated to a separate top level, while the microfluidic process remains on a lower bottom level. This allows for heat shielding of the fluids in the microfluidic process level, and also improve usage of space on the CD. To aid in future implementations of TP pumping on a multi-level 3D CD, studies on the effect of heat source setting, and the effect of positioning the TP feature (it distance from the CD center) on CD surface heating are also presented. In this work, we successfully demonstrate a multi-level 3D approach to implement TP pumping on the microfluidic CD platform. PMID:24110985

  5. Novel multilevel inverter carrier-based PWM method

    SciTech Connect

    Tolbert, L.M.; Habetler, T.G.

    1999-10-01

    The advent of the transformerless multilevel inverter topology has brought forth various pulsewidth modulation (PWM) schemes as a means to control the switching of the active devices in each of the multiple voltage levels in the inverter. An analysis of how existing multilevel carrier-based PWM affects switch utilization for the different levels of a diode-clamped inverter is conducted. Two novel carrier-based multilevel PWM schemes are presented which help to optimize or balance the switch utilization in multilevel inverters. A 10-kW prototype six-level diode-clamped inverter has been built and controlled with the novel PWM strategies proposed in this paper to act as a voltage-source inverter for a motor drive.

  6. Equalizer design for clock recovery based on multi-level optical disk using signal waveform modulation

    NASA Astrophysics Data System (ADS)

    Shao, Meng; Pei, Jing; Yang, Bo

    2013-12-01

    With smaller pits and lands in multi-level optical disks using signal waveform modulation than those in DVD disks, the ISI and nonlinear attenuation of the read-out signal become more serious. One ordinary way is using an equalizer at sample rate 1/T, we proposed one method of designing the equalizer in fixed sample rate with digital interpolation. According to the analysis of the multi-level optical disk channel, we get the target frequency-response cure and implement it with seven order FIR filter. From the result of the read out experiment with multi-level optical disk, the clock of the RF signal could be recovered with the proposed equalizer.

  7. Multi-Level Logic Gate Operation Based on Amplified Aptasensor Performance.

    PubMed

    Feng, Lingyan; Lyu, Zhaozi; Offenhäusser, Andreas; Mayer, Dirk

    2015-06-22

    Conventional electronic circuits can perform multi-level logic operations; however, this capability is rarely realized by biological logic gates. In addition, the question of how to close the gap between biomolecular computation and silicon-based electrical circuitry is still a key issue in the bioelectronics field. Here we explore a novel split aptamer-based multi-level logic gate built from INHIBIT and AND gates that performs a net XOR analysis, with electrochemical signal as output. Based on the aptamer-target interaction and a novel concept of electrochemical rectification, a relayed charge transfer occurs upon target binding between aptamer-linked redox probes and solution-phase probes, which amplifies the sensor signal and facilitates a straightforward and reliable diagnosis. This work reveals a new route for the design of bioelectronic logic circuits that can realize multi-level logic operation, which has the potential to simplify an otherwise complex diagnosis to a "yes" or "no" decision. PMID:25959438

  8. Fig. 1. Single line diagram of 3-phase distribution power system with five inverters in parallel.

    E-print Network

    Silva, Filipe Faria Da

    distribution power system with five inverters in parallel. Harmonic Stability Assessment for Multi- Paralleled@et.aau.dk Abstract--This paper investigates the dynamic interactions of current controllers for multi-paralleled Stability; Paralleled Inverters I. INTRODUCTION In these days, many alternative energy resources have been

  9. Squeezed light from multi-level closed-cycling atomic systems

    NASA Technical Reports Server (NTRS)

    Xiao, Min; Zhu, Yi-Fu

    1994-01-01

    Amplitude squeezing is calculated for multi-level closed-cycling atomic systems. These systems can last without atomic population inversion in any atomic bases. Maximum squeezing is obtained for the parameters in the region of lasing without inversion. A practical four-level system and an ideal three-level system are presented. The latter system is analyzed in some detail and the mechanism of generating amplitude squeezing is discussed.

  10. Multi-level adaptive finite element methods. 1: Variation problems

    NASA Technical Reports Server (NTRS)

    Brandt, A.

    1979-01-01

    A general numerical strategy for solving partial differential equations and other functional problems by cycling between coarser and finer levels of discretization is described. Optimal discretization schemes are provided together with very fast general solvers. It is described in terms of finite element discretizations of general nonlinear minimization problems. The basic processes (relaxation sweeps, fine-grid-to-coarse-grid transfers of residuals, coarse-to-fine interpolations of corrections) are directly and naturally determined by the objective functional and the sequence of approximation spaces. The natural processes, however, are not always optimal. Concrete examples are given and some new techniques are reviewed. Including the local truncation extrapolation and a multilevel procedure for inexpensively solving chains of many boundary value problems, such as those arising in the solution of time-dependent problems.

  11. Fabrication and characterization of multi-level hierarchical surfaces.

    PubMed

    Bhushan, Bharat; Lee, Hyungoo

    2012-01-01

    A nanostructured surface may exhibit low adhesion or high adhesion depending upon fibrillar density, and it presents the possibility of realizing eco-friendly surface structures with desirable adhesion by mimicking the mechanics of fibrillar adhesive surfaces of biological systems. The current research uses a patterning technique to fabricate smart adhesion surfaces: one-, two- and three-level hierarchical synthetic adhesive structure surfaces with various fibrillar densities and diameters. The contact angles and contact angle hysteresis were measured to characterize the wettability. A conventional and a glass ball attached to an atomic force microscope (AFM) tip were used to obtain the adhesive forces via force-distance curves and to study the buckling behavior of a single fiber on the hierarchical structures. PMID:23285631

  12. Generation of Dicke States with Phonon-Mediated Multi-level Stimulated Raman Adiabatic Passage

    E-print Network

    Atsushi Noguchi; Kenji Toyoda; Shinji Urabe

    2012-09-05

    We generate half-excited symmetric Dicke states of two and four ions. We use multi-level stimulated Raman adiabatic passage (STIRAP) whose intermediate states are phonon Fock states. This process corresponds to the spin squeezing operation and half-excited Dicke states are generated during multi-level STIRAP. This method does not require local access for each ion or the preparation of phonon Fock states. Furthermore, it is robust since it is an adiabatic process. We evaluate the Dicke state using a witness operator and determine the upper and lower bounds of the fidelity without using full quantum tomography.

  13. A multi-level solution algorithm for steady-state Markov chains

    NASA Technical Reports Server (NTRS)

    Horton, Graham; Leutenegger, Scott T.

    1993-01-01

    A new iterative algorithm, the multi-level algorithm, for the numerical solution of steady state Markov chains is presented. The method utilizes a set of recursively coarsened representations of the original system to achieve accelerated convergence. It is motivated by multigrid methods, which are widely used for fast solution of partial differential equations. Initial results of numerical experiments are reported, showing significant reductions in computation time, often an order of magnitude or more, relative to the Gauss-Seidel and optimal SOR algorithms for a variety of test problems. The multi-level method is compared and contrasted with the iterative aggregation-disaggregation algorithm of Takahashi.

  14. Comparison of Traditional Inverters and Z-Source Inverter

    Microsoft Academic Search

    Miaosen Shen; Alan Joseph; Jin Wang; Fang Z. Peng; Donald J. Adams

    2005-01-01

    In this paper, three different inverters-traditional PWM inverter, dc\\/dc boosted PWM inverter, and Z-source inverter were investigated and compared using fuel cell vehicle and photovoltaic domestic application as examples. Total switching device power, passive component requirement, and constant power speed ratio of each of these inverters were calculated. For purposes of comparison, an example of the total switching device power,

  15. Multi-level hot zone identification for pedestrian safety.

    PubMed

    Lee, Jaeyoung; Abdel-Aty, Mohamed; Choi, Keechoo; Huang, Helai

    2015-03-01

    According to the National Highway Traffic Safety Administration (NHTSA), while fatalities from traffic crashes have decreased, the proportion of pedestrian fatalities has steadily increased from 11% to 14% over the past decade. This study aims at identifying two zonal levels factors. The first is to identify hot zones at which pedestrian crashes occurs, while the second are zones where crash-involved pedestrians came from. Bayesian Poisson lognormal simultaneous equation spatial error model (BPLSESEM) was estimated and revealed significant factors for the two target variables. Then, PSIs (potential for safety improvements) were computed using the model. Subsequently, a novel hot zone identification method was suggested to combine both hot zones from where vulnerable pedestrians originated with hot zones where many pedestrian crashes occur. For the former zones, targeted safety education and awareness campaigns can be provided as countermeasures whereas area-wide engineering treatments and enforcement may be effective safety treatments for the latter ones. Thus, it is expected that practitioners are able to suggest appropriate safety treatments for pedestrian crashes using the method and results from this study. PMID:25603547

  16. Abstract--A method for fault detection and isolation is proposed and applied to inverter faults in multi-phase drives. An

    E-print Network

    Boyer, Edmond

    . The method is applied to a five-phase permanent-magnet synchronous machine drive. Simulations and experiments-magnet synchronous machine (PMSM) drive. The faults under consideration are: open-phase faults and open-switch faults in multi-phase drives. An analysis of simulations in faulty conditions leads to the derivation of suitable

  17. A multilevel soft-switching inverter with inductor coupling

    Microsoft Academic Search

    Byeong-Mun Song; Junhyung Kim; Jih-Sheng Lai; Ki-Chul Seong; Hae-Jong Kim; Sun-Soon Park

    2001-01-01

    This paper proposes a new soft-switching flying capacitor multilevel inverter that can be generalized and be extended from three levels to any number of levels. The proposed inverter has the advantages of lower voltage and current ratings for auxiliary switches and diodes, achieved by using a coupled inductor and midpoint rail between the DC capacitors. Various aspects, including operation, design,

  18. Reliable inverter systems

    NASA Technical Reports Server (NTRS)

    Nagano, S.

    1979-01-01

    Base driver with common-load-current feedback protects paralleled inverter systems from open or short circuits. Circuit eliminates total system oscillation that can occur in conventional inverters because of open circuit in primary transformer winding. Common feedback signal produced by functioning modules forces operating frequency of failed module to coincide with clock drive so module resumes normal operating frequency in spite of open circuit.

  19. Improving Memory Hierarchy Performance Through Combined Loop Interchange and Multi-Level Fusion

    E-print Network

    Yi, Qing

    Improving Memory Hierarchy Performance Through Combined Loop Interchange and Multi-Level Fusion blocking is the most widely studied method for increasing data reuse, loop interchange and loop fusion can be effective tools as well. Loop fusion enhances locality by merging loops that access similar sets of data

  20. Robust memory-efficient data level information fusion of multi-modal biometric images

    Microsoft Academic Search

    Afzel Noore; Richa Singh; Mayank Vatsa

    2007-01-01

    This paper presents a novel multi-level wavelet based fusion algorithm that com- bines information from fingerprint, face, iris, and signature images of an individual into a single composite image. The proposed approach reduces the memory size, increases the recognition accuracy using multimodal biometric features, and with- stands common attacks such as smoothing, cropping, JPEG 2000, and filtering due to tampering.

  1. Efficient population transfer in a multi-level system using diverging laser beams A. T. Nguyena,

    E-print Network

    Pines, Alexander

    Efficient population transfer in a multi-level system using diverging laser beams A. T. Nguyena, Berkeley, CA 94720-7300 b Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley CA) We investigate a three-step population scheme to efficiently transfer atoms to a particular

  2. METRICFORENSICS: A Multi-Level Approach for Mining Volatile Graphs Keith Henderson

    E-print Network

    significant re- search interest is the cyber-security domain, where internet com- munication traces- ricForensics, a scalable framework for analysis of volatile graphs. MetricForensics combines a multi-level "drill down" approach, a collection of user-selected graph metrics, and a collection of anal- ysis

  3. Comparison of Travel Techniques in a Complex, Multi-Level 3D Environment

    E-print Network

    Lindeman, Robert W.

    -subjects design. A real walking travel technique was compared to two common virtual travel techniques. Participants that utilized the real walking technique were able to place more objects correctly on a map the naive exploration of a complex, multi-level 3D environment, the real walking technique supports a more

  4. Multi-Length Scale-Enriched Continuum-Level Material Model for Kevlar

    E-print Network

    Grujicic, Mica

    Multi-Length Scale-Enriched Continuum-Level Material Model for KevlarÒ -Fiber-Reinforced Polymer the role of various microstructural/morphological defects on the KevlarÒ fiber mechanical properties dynamic ballistic-impact conditions. Keywords ballistics, composites, Kevlar, material models, micro

  5. Autonomous Robots, to appear Jan., 2003. Generating Multi-Level Linguistic Spatial Descriptions from Range Sensor

    E-print Network

    Skubic, Marjorie

    Autonomous Robots, to appear Jan., 2003. 1 Generating Multi-Level Linguistic Spatial Descriptions expressions can be generated to describe the spatial relations between a mobile robot and its environment, using readings from a ring of sonar sensors. Our work is motivated by the study of human-robot

  6. A Multi-Level Assessment of a Program to Teach Medical Students to Teach

    ERIC Educational Resources Information Center

    Blatt, Benjamin; Greenberg, Larrie

    2007-01-01

    Few longitudinal programs exist to teach senior students (MS4s) to be teachers, nor have there been any reports of comprehensive program evaluation in this area. The primary objectives of this study were to describe our ongoing faculty development effort and to develop a multi-level program evaluation, using Dixon's model. The TALKS (Teaching and…

  7. Handling Conflicts through Multi-level Editing in Peer-to-peer Environments

    E-print Network

    Paris-Sud XI, Université de

    Handling Conflicts through Multi-level Editing in Peer-to-peer Environments Claudia-Lavinia Ignat editing over hier- archical documents in peer-to-peer networks is a very impor- tant issue. In this paper to work disconnected from the network we have used, a replicated architecture where users edit copies

  8. Codes for Asymmetric Limited-Magnitude Errors with Application to Multi-Level Flash Memories

    E-print Network

    Bruck, Jehoshua (Shuki)

    1 Codes for Asymmetric Limited-Magnitude Errors with Application to Multi-Level Flash Memories of Multilevel Flash Memories induce errors that have low magnitudes and are dominantly asymmetric. This paper studies block codes for asymmetric limited-magnitude errors over q-ary channels. We propose code

  9. Codes for Asymmetric Limited-Magnitude Errors with Application to Multi-Level Flash Memories

    E-print Network

    Bruck, Jehoshua (Shuki)

    1 Codes for Asymmetric Limited-Magnitude Errors with Application to Multi-Level Flash Memories Memories induce errors that have low magnitudes and are dominantly asymmetric. This paper studies block codes for asymmetric limited-magnitude errors over q-ary channels. We propose code constructions

  10. Bit-fixing Codes for Multi-level Cells Anxiao (Andrew) Jiang

    E-print Network

    Jiang, Anxiao "Andrew"

    Bit-fixing Codes for Multi-level Cells Anxiao (Andrew) Jiang Computer Science and Eng. Dept. Texas. Texas A&M University College Station, TX 77843 yli@cse.tamu.edu Jehoshua Bruck Electrical Engineering, · · · , e1, e0), and the codes are designed such that every error bit ei only affects the codeword

  11. Data Provenance architecture to support Information Assurance in a MultiLevel Secure Environment

    Microsoft Academic Search

    Abha Moitra; Bruce Barnett; Andrew Crapo; Stephen J Dill

    2009-01-01

    We describe a framework for capturing data provenance information to support Information assurance attributes like availability, authentication, confidentiality, integrity and non-repudiation. Our approach is applicable to multi-level secure systems where it is not always possible to directly provide data source and data transformation information. We achieve this by combining the subjective and objective trust in data as a \\

  12. The observation of seiches in the Baltic Sea using a multi data set of water levels

    Microsoft Academic Search

    Margitta Metzner; Martin Gade; Ingo Hennings; Alexander B Rabinovich

    2000-01-01

    This investigation addresses the difficult problem of using a multi data set of water levels to study seich oscillations in the Baltic Sea. The Baltic Sea is a semi-enclosed sea area and is connected with the North Atlantic Ocean through the North Sea. The applied method is based on the analysis of environmentally corrected radar altimeter (RA) data in conjunction

  13. VAR management in power systems: Basic objectives, solutions and multi-level converters for STATCOM applications

    Microsoft Academic Search

    M. N. Slepchenkov; K. M. Smedley

    2009-01-01

    This paper describes various problems in transmission and distribution systems and demonstrates the significance of reactive power management. Static VAR compensator and STATCOM principles of operation and power characteristics are described. The most common types of multilevel voltage source converters used in STATCOM applications are comparatively analyzed. The most promising topology of multi-level Hexagram converter is adduced. The efficiency of

  14. Low and High-Level Visual Feature Based Apple Detection from Multi-modal Images

    E-print Network

    Wachs, Juan

    1 Low and High-Level Visual Feature Based Apple Detection from Multi-modal Images J. P. Wachs1 , H discusses the development of a machine vision system, capable of recognizing occluded green apples within a tree canopy. This involves the detection of "green" apples within scenes of "green leaves", shadow

  15. Improving MultiLevel NAND Flash Memory Storage Reliability Using Concatenated BCH-TCM Coding

    Microsoft Academic Search

    Shu Li; Tong Zhang

    2010-01-01

    By storing more than one bit in each memory cell, multi-level per cell (MLC) NAND flash memories are dominating global flash memory market due to their appealing storage density advantage. However, continuous technology scaling makes MLC NAND flash memories increasingly subject to worse raw storage reliability. This paper presents a memory fault tolerance design solution geared to MLC NAND flash

  16. Improving multi-level NAND flash memory storage reliability using concatenated TCM-BCH coding

    Microsoft Academic Search

    Shu Li; Tong Zhang

    2009-01-01

    By storing multiple bits in each memory cell, multi-level per cell (MLC) NAND flash memories have been increasingly dominant in the flash memory market due to their obvious storage density advantage. However, MLC NAND flash memories are much more subject to storage reliability degradation as the technology continues to scale down. This paper presents an error correcting solution by concatenating

  17. A Multi-level Approach to Biologically Inspired Robotic Systems1 Alfredo Weitzenfeld

    E-print Network

    Weitzenfeld, Alfredo

    A Multi-level Approach to Biologically Inspired Robotic Systems1 Alfredo Weitzenfeld Departmento Abstract The study of biological systems has inspired the development of a large number of neural network architectures and robotic implementations. Through both experimentation and simulation biological systems

  18. Multi-Level Free-Space Dilation for Sampling Narrow Passages in PRM Planning

    E-print Network

    Pratt, Vaughan

    Multi-Level Free-Space Dilation for Sampling Narrow Passages in PRM Planning David Hsu, Gildardo S configurations sampled from C and whose edges are simple collision-free paths between the nodes. This way, PRM Department of Computer Science, Stanford University, Stanford, CA 94305, USA Abstract-- Free-space dilation

  19. Multi-Level Free-Space Dilation for Sampling Narrow Passages in PRM Planning

    E-print Network

    Cheng, Ho-lun, "Alan"

    Multi-Level Free-Space Dilation for Sampling Narrow Passages in PRM Planning David Hsu, Gildardo S a probabilistic roadmap. A roadmap is a graph whose nodes are the collision-free configurations sampled from C. on Robotics & Automation, 2006 Abstract-- Free-space dilation is an effective approach for narrow passage

  20. Reliability and failure analysis study of multi-die embedded micro wafer level packages

    Microsoft Academic Search

    V. N. Sekhar; V. S. Rao; Gaurav Sharma; Ranjan Rajoo; S. T. M. Ling; Khong Chee Houe; Chong Ser Choong; Cheng Cheng Kuo

    2010-01-01

    Main objective of this study is to design and development of multi-die embedded micro wafer level packages (EMWLP) reliability test vehicles. Such as, the laterally placed die EMWLP and the vertically stacked thin die EMWLP. For reliability evaluation, EMWLPs have been subjected to both environmental and mechanical reliability tests as per JEDEC standards. These reliability tests include highly accelerated stress

  1. TAC Conceptual Framework DRAFT 2 Multi-level Technical Assistance Strategy

    E-print Network

    Awtar, Shorya

    by identifying common themes through (qualitative) analysis contained in a variety of documents, such as: GNI (Brightmoor ­ Trina; Osborn ­ Leslie; Southwest-Larry). · Technical assistance briefs This is the most commonTAC Conceptual Framework DRAFT 2 May 2007 Multi-level Technical Assistance Strategy Cross

  2. Managing multi-mode tasks with time cost and quality levels using optimal discrete control synthesis

    E-print Network

    Paris-Sud XI, Université de

    Managing multi-mode tasks with time cost and quality levels using optimal discrete control- ing quality. We outline a technique for the automatic gen- eration of such controllers involving.inrialpes.fr/bip Abstract Real-time control systems are complex to design, and au- tomation support is important. We

  3. GROUND WATER MONITORING AND SAMPLING: MULTI-LEVEL VERSUS TRADITIONAL METHODS WHATS WHAT?

    EPA Science Inventory

    After years of research and many publications, the question still remains: What is the best method to collect representative ground water samples from monitoring wells? Numerous systems and devices are currently available for obtaining both multi-level samples as well as traditi...

  4. Accounting for Phonetic and Syntactic Phenomena in a Multi-Level Competitive Interaction Model

    E-print Network

    Möbius, Bernd

    Accounting for Phonetic and Syntactic Phenomena in a Multi-Level Competitive Interaction Model, exemplar the- ory has enjoyed much growth in the field of phonetics. More recently, attempts have been made to apply exemplar theory to syn- tactic phenomena. Thus far, the issue of unifying phonetic and syntactic

  5. Multi-Level Research on Youth Participation in the Haitian Reconstruction

    ERIC Educational Resources Information Center

    Pluim, Gary W. J.

    2012-01-01

    Research in comparative and international education routinely encounters exceptional research conditions. In this article, the author explores the particular issues he faced in his research on multi-level youth programs of the Haitian reconstruction. Through a vertical analysis of internationally sponsored programs, this study required special…

  6. Multi-Level Analysis Methodology. Final Report, November 1976-June 1978

    ERIC Educational Resources Information Center

    Fennessey, James; Karweit, Nancy

    This final report describes a research project in sociology of education. The general objective of the project was to develop a framework for analyzing and conceptualizing multi-level social processes that will allow researchers to examine and represent school and classroom socialization structures and their effects. The framework is based on a…

  7. Fields of Dreams, Fields of Schemes: Ponzi Finance and MultiLevel Marketing in South Africa

    Microsoft Academic Search

    Detlev Krige

    2012-01-01

    The structural conditions associated with increased inequality amidst rapid change brought about by growing financialization and efforts to get the ‘unbanked’ sections of society into the formal financial system have created the conditions under which illegal pyramid and ponzi schemes, fake investment schemes, and legal multi-level marketing companies have been able to flourish. In contemporary Johannesburg and Soweto the originators

  8. Microbiological analysis of multi-level borehole samples from a contaminated groundwater system

    Microsoft Academic Search

    R. W. Pickup; G. Rhodes; M. L. Alamillo; H. E. H. Mallinson; S. F. Thornton; D. N. Lerner

    2001-01-01

    A range of bacteriological, geochemical process-related and molecular techniques have been used to assess the microbial biodegradative potential in groundwater contaminated with phenol and other tar acids. The contaminant plume has travelled 500 m from the pollutant source over several decades. Samples were obtained from the plume using a multi-level sampler (MLS) positioned in two boreholes (boreholes 59 and 60)

  9. A multi-level approach to the integration of traffic data within GIS

    E-print Network

    Bargiela, Andrzej

    A multi-level approach to the integration of traffic data within GIS Kalin Penev, Christophe systems are designed and used in many application fields. Geographical Information Systems (GIS) have now challenges for GIS is to generate a corporate resource whose full potential will be achieved by making

  10. Multi-Level Graph Layout on the GPU Yaniv Frishman, Student Member, IEEE and Ayellet Tal

    E-print Network

    Tal, Ayellet

    Multi-Level Graph Layout on the GPU Yaniv Frishman, Student Member, IEEE and Ayellet Tal Abstract-- This paper presents a new algorithm for force directed graph layout on the GPU. The algorithm, whose goal is to compute layouts accurately and quickly, has two contributions. The first contribution is proposing

  11. Multi-Level Assessment of Scientific Content Knowledge Gains Associated with Socioscientific Issues-Based Instruction

    ERIC Educational Resources Information Center

    Klosterman, Michelle L.; Sadler, Troy D.

    2010-01-01

    This study explored the impact of using a socioscientific issue (SSI) based curriculum on developing science content knowledge. Using a multi-level assessment design, student content knowledge gains were measured before and after implementation of a three-week unit on global warming (a prominent SSI) that explored both the relevant science content…

  12. Can Multi-Level Cell PCM Be Reliable and Usable? Analyzing the Impact of Resistance Drift

    E-print Network

    Lee, Hsien-Hsin "Sean"

    Can Multi-Level Cell PCM Be Reliable and Usable? Analyzing the Impact of Resistance Drift Sungkap for their practical deployment. To address this reliability issue, many researchers proposed material-based or architectural solutions. In this paper, we analyze the resistance drift problem using both analytical models

  13. A Multi-Level Analysis of Risk Factors for Campylobacter spp. in Broiler Chickens in Iceland

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Introduction We carried out a longitudinal study of the broiler industry in Iceland between May 2001 and September 2004. Using multi-level statistical methods, our objective was to determine which aspects of the birds, their management and/or their housing may be most useful for applying interventi...

  14. Fuzzy based automatic multi-level vehicle parking using lab view

    Microsoft Academic Search

    K. A. Sunitha; K. Prema; G. Sai Deepthi; E. J. E. Belinda; N. Senthil Kumar

    2010-01-01

    This paper introduces a method of automatic multilevelcar parking system that parks the vehicle in reduced space using the conditions based on fuzzy logic controller. It possibly controls the traffic and avoids traffic congestion. This automatic multi-level vehicle stacking system also has online access to book the parking slot in advance which is interfaced with the LabVIEW. The vehicle placed

  15. Late Cretaceous sea-level changes in Tunisia: a multi-disciplinary approach

    Microsoft Academic Search

    LIANGQUAN LI; GERTA KELLER; THIERRY ADATTE; WOLFGANG STINNESBECK

    2000-01-01

    A multi-disciplinary study of sea-level and climate proxies, including bulk rock and clay mineral compositions, carbon isotopes, total organic carbon (TOC), Sr\\/Ca ratios, and macro- and microfaunal associations, reveals seven major sea-level regressions in the southwestern Tethys during the last 10 million years of the Cretaceous: late Campanian (c. 74.2 Ma, 73.4-72.5 Ma and 72.2-71.7 Ma), early Maastrich- tian (70.7-70.3

  16. A MultiLevel Super Peer Based P2P Architecture

    Microsoft Academic Search

    Zhao Cao; Kan Li; Yushu Liu

    2008-01-01

    Most existing super peer based Peer-to-Peer (P2P) systems have only one level super peer, it can not support hierarchical P2P architecture, especially, the effectiveness, efficiency and scalability can not satisfy some application's requirements with the growth of the system. In this paper, we design a P2P system with hierarchical structure. First, we propose a Multi-Level Super Peer (MLSP) based P2P

  17. Spatial principles of level-design in multi-player first-person shooters

    Microsoft Academic Search

    Christian Güttler; Troels Degn Johansson

    2003-01-01

    Basing itself on a theoretical discussion and experiments, this paper outlines the basic spatial principles of level design in multi-player first-person shooters with special reference to Counter-Strike (Sierra). In this manner, the paper seeks to outline a heuristics of level design in firstperson shooters. The thesis of the paper is that a consistent examination of a game's gameplay, its agents,

  18. Accelerated proximity queries between convex polyhedra by multi-level Voronoi marching

    Microsoft Academic Search

    Stephen A. Ehmann; Ming C. Lin

    2000-01-01

    We present an accelerated proximity query algorithm between moving convex polyhedra. The algorithm combines Voronoi-based feature tracking with a multi-level-of-detail representation, in order to adapt to the variation in levels of coherence and speed up the computation. It provides a progressive refinement framework for collision detection and distance queries. We have implemented our algorithm and have observed significant performance improvements

  19. An adaptive multi-level simulation algorithm for stochastic biological systems.

    PubMed

    Lester, C; Yates, C A; Giles, M B; Baker, R E

    2015-01-14

    Discrete-state, continuous-time Markov models are widely used in the modeling of biochemical reaction networks. Their complexity often precludes analytic solution, and we rely on stochastic simulation algorithms (SSA) to estimate system statistics. The Gillespie algorithm is exact, but computationally costly as it simulates every single reaction. As such, approximate stochastic simulation algorithms such as the tau-leap algorithm are often used. Potentially computationally more efficient, the system statistics generated suffer from significant bias unless tau is relatively small, in which case the computational time can be comparable to that of the Gillespie algorithm. The multi-level method [Anderson and Higham, "Multi-level Monte Carlo for continuous time Markov chains, with applications in biochemical kinetics," SIAM Multiscale Model. Simul. 10(1), 146-179 (2012)] tackles this problem. A base estimator is computed using many (cheap) sample paths at low accuracy. The bias inherent in this estimator is then reduced using a number of corrections. Each correction term is estimated using a collection of paired sample paths where one path of each pair is generated at a higher accuracy compared to the other (and so more expensive). By sharing random variables between these paired paths, the variance of each correction estimator can be reduced. This renders the multi-level method very efficient as only a relatively small number of paired paths are required to calculate each correction term. In the original multi-level method, each sample path is simulated using the tau-leap algorithm with a fixed value of ?. This approach can result in poor performance when the reaction activity of a system changes substantially over the timescale of interest. By introducing a novel adaptive time-stepping approach where ? is chosen according to the stochastic behaviour of each sample path, we extend the applicability of the multi-level method to such cases. We demonstrate the efficiency of our method using a number of examples. PMID:25591344

  20. Enabling multi-level relevance feedback on PubMed by integrating rank learning into DBMS

    PubMed Central

    2010-01-01

    Background Finding relevant articles from PubMed is challenging because it is hard to express the user's specific intention in the given query interface, and a keyword query typically retrieves a large number of results. Researchers have applied machine learning techniques to find relevant articles by ranking the articles according to the learned relevance function. However, the process of learning and ranking is usually done offline without integrated with the keyword queries, and the users have to provide a large amount of training documents to get a reasonable learning accuracy. This paper proposes a novel multi-level relevance feedback system for PubMed, called RefMed, which supports both ad-hoc keyword queries and a multi-level relevance feedback in real time on PubMed. Results RefMed supports a multi-level relevance feedback by using the RankSVM as the learning method, and thus it achieves higher accuracy with less feedback. RefMed "tightly" integrates the RankSVM into RDBMS to support both keyword queries and the multi-level relevance feedback in real time; the tight coupling of the RankSVM and DBMS substantially improves the processing time. An efficient parameter selection method for the RankSVM is also proposed, which tunes the RankSVM parameter without performing validation. Thereby, RefMed achieves a high learning accuracy in real time without performing a validation process. RefMed is accessible at http://dm.postech.ac.kr/refmed. Conclusions RefMed is the first multi-level relevance feedback system for PubMed, which achieves a high accuracy with less feedback. It effectively learns an accurate relevance function from the user’s feedback and efficiently processes the function to return relevant articles in real time. PMID:20406504

  1. Design of a Robust Digital Current Controller for a Grid Connected Interleaved Inverter

    E-print Network

    for a three- phase voltage source grid-connected interleaved inverter. Each phase consists of 6 half of the commercially available power electronic interface inverters are based on the two-level voltage source topology half the voltage rating of the power switches in a 2-level inverter, and hence have faster switching

  2. An inverter/controller subsystem optimized for photovoltaic applications

    NASA Technical Reports Server (NTRS)

    Pickrell, R. L.; Osullivan, G.; Merrill, W. C.

    1978-01-01

    Conversion of solar array dc power to ac power stimulated the specification, design, and simulation testing of an inverter/controller subsystem tailored to the photovoltaic power source characteristics. Optimization of the inverter/controller design is discussed as part of an overall photovoltaic power system designed for maximum energy extraction from the solar array. The special design requirements for the inverter/ controller include: a power system controller (PSC) to control continuously the solar array operating point at the maximum power level based on variable solar insolation and cell temperatures; and an inverter designed for high efficiency at rated load and low losses at light loadings to conserve energy.

  3. A novel method for a multi-level hierarchical composite with brick-and-mortar structure

    PubMed Central

    Brandt, Kristina; Wolff, Michael F. H.; Salikov, Vitalij; Heinrich, Stefan; Schneider, Gerold A.

    2013-01-01

    The fascination for hierarchically structured hard tissues such as enamel or nacre arises from their unique structure-properties-relationship. During the last decades this numerously motivated the synthesis of composites, mimicking the brick-and-mortar structure of nacre. However, there is still a lack in synthetic engineering materials displaying a true hierarchical structure. Here, we present a novel multi-step processing route for anisotropic 2-level hierarchical composites by combining different coating techniques on different length scales. It comprises polymer-encapsulated ceramic particles as building blocks for the first level, followed by spouted bed spray granulation for a second level, and finally directional hot pressing to anisotropically consolidate the composite. The microstructure achieved reveals a brick-and-mortar hierarchical structure with distinct, however not yet optimized mechanical properties on each level. It opens up a completely new processing route for the synthesis of multi-level hierarchically structured composites, giving prospects to multi-functional structure-properties relationships. PMID:23900554

  4. A generalized zero-current-transition concept to simplify three-phase soft-switching inverters

    Microsoft Academic Search

    Yong Li; Fred C. Lee

    2001-01-01

    A concept of a generic half-bridge zero-current-transition (ZCT) cell is developed, which employs one auxiliary switch and one LC resonant tank to assist switching transitions. Application of the concept leads to the discovery of a family of simplified soft-switching inverters, including two-level inverters using only three auxiliary switches and three-level inverters using six auxiliary switches. Unlike existing techniques, these inverters

  5. Norm Adaptation using a Two-Level Multi-Agent System Architecture in a Peer-to-Peer Scenario

    E-print Network

    López-Sánchez, Maite

    Norm Adaptation using a Two-Level Multi-Agent System Architecture in a Peer-to-Peer Scenario Jordi the Assistance Layer. Our abstract Two Level Assisted MAS Architecture (2-LAMA) incorporates such a layer. We

  6. Resonant snubber inverter

    DOEpatents

    Lai, J.S.; Young, R.W. Sr.; Chen, D.; Scudiere, M.B.; Ott, G.W. Jr.; White, C.P.; McKeever, J.W.

    1997-06-24

    A resonant, snubber-based, soft switching, inverter circuit achieves lossless switching during dc-to-ac power conversion and power conditioning with minimum component count and size. Current is supplied to the resonant snubber branches solely by the main inverter switches. Component count and size are reduced by use of a single semiconductor switch in the resonant snubber branches. Component count is also reduced by maximizing the use of stray capacitances of the main switches as parallel resonant capacitors. Resonance charging and discharging of the parallel capacitances allows lossless, zero voltage switching. In one embodiment, circuit component size and count are minimized while achieving lossless, zero voltage switching within a three-phase inverter. 14 figs.

  7. Resonant snubber inverter

    DOEpatents

    Lai, Jih-Sheng (Knoxville, TN); Young, Sr., Robert W. (Oak Ridge, TN); Chen, Daoshen (Knoxville, TN); Scudiere, Matthew B. (Oak Ridge, TN); Ott, Jr., George W. (Knoxville, TN); White, Clifford P. (Knoxville, TN); McKeever, John W. (Oak Ridge, TN)

    1997-01-01

    A resonant, snubber-based, soft switching, inverter circuit achieves lossless switching during dc-to-ac power conversion and power conditioning with minimum component count and size. Current is supplied to the resonant snubber branches solely by the main inverter switches. Component count and size are reduced by use of a single semiconductor switch in the resonant snubber branches. Component count is also reduced by maximizing the use of stray capacitances of the main switches as parallel resonant capacitors. Resonance charging and discharging of the parallel capacitances allows lossless, zero voltage switching. In one embodiment, circuit component size and count are minimized while achieving lossless, zero voltage switching within a three-phase inverter.

  8. Barriers to Uptake of Conservation Agriculture in southern Africa: Multi-level Analyses from Malawi

    NASA Astrophysics Data System (ADS)

    Dougill, Andrew; Stringer, Lindsay; Whitfield, Stephen; Wood, Ben; Chinseu, Edna

    2015-04-01

    Conservation agriculture is a key set of actions within the growing body of climate-smart agriculture activities being advocated and rolled out across much of the developing world. Conservation agriculture has purported benefits for environmental quality, food security and the sustained delivery of ecosystem services. In this paper, new multi-level analyses are presented, assessing the current barriers to adoption of conservation agriculture practices in Malawi. Despite significant donor initiatives that have targeted conservation agriculture projects, uptake rates remain low. This paper synthesises studies from across 3 levels in Malawi: i.) national level- drawing on policy analysis, interviews and a multi-stakeholder workshop; ii.) district level - via assessments of development plans and District Office and extension service support, and; iii) local level - through data gained during community / household level studies in Dedza District that have gained significant donor support for conservation agriculture as a component of climate smart agriculture initiatives. The national level multi-stakeholder Conservation Agriculture workshop identified three areas requiring collaborative research and outlined routes for the empowerment of the National Conservation Agriculture Task Force to advance uptake of conservation agriculture and deliver associated benefits in terms of agricultural development, climate adaptation and mitigation. District level analyses highlight that whilst District Development Plans are now checked against climate change adaptation and mitigation criteria, capacity and knowledge limitations exist at the District level, preventing project interventions from being successfully up-scaled. Community level assessments highlight the need for increased community participation at the project-design phase and identify a pressing requirement for conservation agriculture planning processes (in particular those driven by investments in climate-smart agriculture) to better accommodate, and respond to, the differentiated needs of marginalised groups (e.g. poor, elderly, carers). We identify good practices that can be used to design, plan and implement conservation agriculture projects such that the multiple benefits can be realised. We further outline changes to multi-level policy and institutional arrangements to facilitate greater adoption of conservation agriculture in Malawi, noting the vital importance of District-level institutions and amendments and capacity building required within agricultural extension services. We highlight the need for capacity building and support to ensure conservation agriculture's multiple benefits are realised more widely as a route towards sustainable land management.

  9. Postfault Control Strategy for the Hexagram Inverter Motor Drive

    Microsoft Academic Search

    Liang Zhou; Keyue Ma Smedley

    2010-01-01

    This paper discusses the fault tolerance ability of the hexagram inverter motor drive. Due to its unique interconnecting nature, the hexagram inverter can tolerate one leg failure without modifying the power circuit topology. In the event of one leg failure, the control circuit can reconfigure the trigger signals to maintain a smooth torque operation at a reduced power level. When

  10. Parallel operation of voltage source inverters with minimal intermodule reactors

    Microsoft Academic Search

    Bin Shi; Giri Venkataramanan

    2004-01-01

    Realization of large horsepower motor drives using parallel-connected voltage source inverters rated at smaller power levels would be highly desirable. A robust technique for such a realization would result in several benefits including modularity, ease of maintenance, n+1 redundancy, reliability, etc. Techniques for parallel operation of voltage source inverters with relatively large load inductance have been well established in the

  11. Hybrid Multilevel Inverter with Single DC Haiwen Liu1

    E-print Network

    Tolbert, Leon M.

    Hybrid Multilevel Inverter with Single DC Source Haiwen Liu1 , Leon M. Tolbert1, 2 , Burak Ozpineci a desired high voltage from several levels of dc voltages [1][2][3]. The dc sources can be batteries, fuel. source. The top is an H-bridge in series with each standard inverter leg. The H-bridge can use a separate

  12. Can programming be liberated from the two-level style: multi-level programming with deepjava

    Microsoft Academic Search

    Thomas Kühne; Daniel Schreiber

    2007-01-01

    Since the introduction of object-oriented programming few programming languages have attempted to provide program- mers with more than objects and classes, i.e., more than two levels. Those that did, almost exclusively aimed at de- scribing language properties—i.e., their metaclasses exert linguistic control on language concepts and mechanisms— often in order to make the language extensible. In terms of supporting logical

  13. Program Predicts Nonlinear Inverter Performance

    NASA Technical Reports Server (NTRS)

    Al-Ayoubi, R. R.; Oepomo, T. S.

    1985-01-01

    Program developed for ac power distribution system on Shuttle orbiter predicts total load on inverters and node voltages at each of line replaceable units (LRU's). Mathematical model simulates inverter performance at each change of state in power distribution system.

  14. A fast multi-level method for the fixed point form of matrix H-equations

    SciTech Connect

    Kelley, C.T. (North Carolina State Univ., Raleigh (United States)); Northrup, J.I. (Colby College, Waterville, ME (United States))

    1993-01-01

    In previous work quasi-Newton and multi-level algorithms for fully nonlinear integral equations were designed and analyzed. The motivating examples for that work were analogs of the Chandrasekhar H-equation for matrix-valued functions. A weakness of these algorithms was that transfer between grids was done with a piecewise linear interpolation instead of Nystroem interpolation. This choice of interpolation was used because the nonlinearity in the Chandrasekhar equation was expressed in the quadratic form for which a matrix inversion is not required. In this paper the fixed point formulation is reconsidered and a conditioning issue associated with the matrix is resolved. This allows use of Nystroem interpolation and thereby a more efficient multi-level method. Implementation details on the Alliant FX series of multiprocessor computers is also discussed. 18 refs., 3 tabs.

  15. A MultiLevel Assessment of a Program to Teach Medical Students to Teach

    Microsoft Academic Search

    Benjamin Blatt; Larrie Greenberg

    2007-01-01

    Few longitudinal programs exist to teach senior students (MS4s) to be teachers, nor have there been any reports of comprehensive\\u000a program evaluation in this area. The primary objectives of this study were to describe our ongoing faculty development effort\\u000a and to develop a multi-level program evaluation, using Dixon’s model. The TALKS (Teaching and Learning Communication Skills)\\u000a program is a senior

  16. The Low-Level Control System for the CERN PS MultiTurn Extraction Kickers

    Microsoft Academic Search

    J Schipper; B Bleus; C Boucly; E Carlier; T Fowler; H Gaudillet; R Noulibos; L Sermeus

    2010-01-01

    To reduce the beam losses when preparing high intensity proton beam for the CERN Neutrino to Gran Sasso (CNGS) facility, a new Multi-Turn extraction (MTE) scheme has been implemented in the PS, to replace the present Continuous Transfer (CT) to the SPS. Industrial off-the-shelf components have been used for the low-level part of the MTE kicker control system. National Instruments

  17. Performance of asynchronous algorithms in multi-level data-driven systems

    SciTech Connect

    Gaudiot, J.L.; Lin, C.M.

    1989-12-31

    Asynchronous algorithms are efficient methods in solving scientific and engineering problems. Much research has been devoted to the study of asynchronous algorithms in different areas. This paper will show asynchronous algorithms applied to logic circuit simulation, communication networks, partial differential equations (PDE) and artificial neural networks, and as well as implementations of these asynchronous algorithms on a special class of multiprocessor systems, namely Multi-level Tagged-token Data-flow (MTD) architectures.

  18. A multi-level adaptive solution strategy for 3D inverse problems in pool boiling

    Microsoft Academic Search

    Yi Heng; Maka Karalashvili; Adel Mhamdi; Wolfgang Marquardt

    2011-01-01

    Purpose – The purpose of this paper is to present an efficient algorithm based on a multi-level adaptive mesh refinement strategy for the solution of ill-posed inverse heat conduction problems arising in pool boiling using few temperature observations. Design\\/methodology\\/approach – The stable solution of the inverse problem is obtained by applying the conjugate gradient method for the normal equation method

  19. Identification of rickettsial isolates at the species level using multi-spacer typing

    Microsoft Academic Search

    Pierre-Edouard Fournier; Didier Raoult

    2007-01-01

    BACKGROUND: In order to estimate whether multi-spacer typing (MST), based on the sequencing of variable intergenic spacers, could serve for the identification of Rickettsia at the species level, we applied it to 108 rickettsial isolates or arthropod amplicons that include representatives of 23 valid Rickettsia species. RESULTS: MST combining the dksA-xerC, mppA-purC, and rpmE-tRNAfMet spacer sequences identified 61 genotypes, allowing

  20. Energy-Saving Inverter

    NASA Technical Reports Server (NTRS)

    Rippel, W. E.; Edwards, D. B.

    1984-01-01

    Commutation by field-effect transistor allows more efficient operation. High voltage field-effect transistor (FET) controls silicon controlled rectifiers (SCR's). Circuit requires only one capacitor and one inductor in commutation circuit: simpler, more efficient, and more economical than conventional inverters. Adaptable to dc-to-dc converters.

  1. Invertibility of irreducible matrices

    Microsoft Academic Search

    Shangjun Yang; Xiaodong Zhang

    1997-01-01

    We obtain new sufficient conditions for invertibility of an irreducible complex matrix. Remarks are also given on eigenvalues (and the associated eigenvectors) that lie on the boundary of various spectrum inclusion regions of an irreducible matrix. Our results extend, strengthen, or clarify the recent work of Brualdi, Brualdi and Mellendorff, Farid, Solov'ev, and Zhang and Gu.

  2. Multi-Level Determinants of Parasitic Fly Infection in Forest Passerines

    PubMed Central

    Manzoli, Darío Ezequiel; Antoniazzi, Leandro Raúl; Saravia, María José; Silvestri, Leonardo; Rorhmann, David; Beldomenico, Pablo Martín

    2013-01-01

    The study of myiasis is important because they may cause problems to the livestock industry, public health, or wildlife conservation. The ecology of parasitic dipterans that cause myiasis is singular, as they actively seek their hosts over relatively long distances. However, studies that address the determinants of myiasis dynamics are very scarce. The genus Philornis include species that may be excellent models to study myiasis ecology, as they exclusively parasitize bird nestlings, which stay in their nests until they are fully fledged, and larvae remain at the point of entry until the parasitic stage is over, thus allowing the collection of sequential individual-level infection data from virtually all the hosts present at a particular area. Here we offer a stratified multi-level analysis of longitudinal data of Philornis torquans parasitism in replicated forest bird communities of central Argentina. Using Generalized Linear Models and Generalized Linear Mixed Models and an information theory approach for model selection, we conducted four groups of analyses, each with a different study unit, the individual, the brood, the community at a given week, and the community at a given year. The response variable was larval abundance per nestling or mean abundance per nestling. At each level, models included the variables of interest of that particular level, and also potential confounders and effect modifiers of higher levels. We found associations of large magnitude at all levels, but only few variables truly governed the dynamics of this parasite. At the individual level, the infection was determined by the species and the age of the host. The main driver of parasite abundance at the microhabitat level was the average height of the forest, and at the community level, the density of hosts and prior rainfall. This multi-level approach contributed to a better understanding of the ecology of myiasis. PMID:23874408

  3. A Multi-Level Approach to Outreach for Geologic Sequestration Projects

    USGS Publications Warehouse

    Greenberg, S.E.; Leetaru, H.E.; Krapac, I.G.; Hnottavange-Telleen, K.; Finley, R.J.

    2009-01-01

    Public perception of carbon capture and sequestration (CCS) projects represents a potential barrier to commercialization. Outreach to stakeholders at the local, regional, and national level is needed to create familiarity with and potential acceptance of CCS projects. This paper highlights the Midwest Geological Sequestration Consortium (MGSC) multi-level outreach approach which interacts with multiple stakeholders. The MGSC approach focuses on external and internal communication. External communication has resulted in building regional public understanding of CCS. Internal communication, through a project Risk Assessment process, has resulted in enhanced team communication and preparation of team members for outreach roles. ?? 2009 Elsevier Ltd. All rights reserved.

  4. Conservative treatment of boundary interfaces for overlaid grids and multi-level grid adaptations

    NASA Technical Reports Server (NTRS)

    Moon, Young J.; Liou, Meng-Sing

    1989-01-01

    Conservative algorithms for boundary interfaces of overlaid grids are presented. The basic method is zeroth order, and is extended to a higher order method using interpolation and subcell decomposition. The present method, strictly based on a conservative constraint, is tested with overlaid grids for various applications of unsteady and steady supersonic inviscid flows with strong shock waves. The algorithm is also applied to a multi-level grid adaptation in which the next level finer grid is overlaid on the coarse base grid with an arbitrary orientation.

  5. Multi-length scale computational derivation of Kevlar ® yarn-level material model

    Microsoft Academic Search

    M. Grujicic; P. S. Glomski; B. Pandurangan; W. C. Bell; C. F. Yen; B. A. Cheeseman

    2011-01-01

    The results of an extensive set of molecular-level computational analyses regarding the role of various microstructural\\/morphological\\u000a defects on the Kevlar® fiber mechanical properties are used to upgrade the associated yarn-level model of the same material. While carrying out\\u000a this analysis, the hierarchical multi-scale (atoms\\/ions—molecular chains—fibrils—fibers—yarn) of the problem was taken into\\u000a account. To construct various defects, the appropriate open-literature experimental

  6. A multilevel voltage-source inverter with separate dc sources for static var generation

    SciTech Connect

    Peng, Fang Zheng [Tennessee Univ., Knoxville, TN (United States)]|[Oak Ridge National Lab., TN (United States); Lai, Jih-Sheng; McKeever, J.; VanCoevering, J. [Oak Ridge National Lab., TN (United States)

    1995-09-01

    A new multilevel voltage-source inverter with a separate dc sources is proposed for high-voltage, high-power applications, such as flexible ac transmission systems (FACTS) including static var generation (SVG), power line conditioning, series compensation, phase shifting, voltage balancing, fuel cell and photovoltaic utility systems interfacing, etc. The new M-level inverter consists of (M-1)/2 single phase full bridges in which each bridge has its own separate dc source. This inverter can generate almost sinusoidal waveform voltage with only one time switching per cycle as the number of levels increases. It can solve the problems of conventional transformer-based multipulse inverters and the problems of the multilevel diode-clamped inverter and the multilevel flying capacitor inverter. To demonstrate the superiority of the new inverter, a SVG system using the new inverter topology is discussed through analysis, simulation and experiment.

  7. System Design Method for a Load Commutated Inverter-Synchronous Motor Drive

    Microsoft Academic Search

    Allan B. Plunkett; Fred G. Turnbull

    1984-01-01

    In a thyristorized load commutated inverter synchronous motor drive system, the inverter relies on the back EMF of the synchronous motor to provide the reverse voltage for commutation. The level of the back EMF is a function of both the synchronous motor's field current and rotational speed. The inverter operating frequency is determined by the motor speed and number of

  8. Space vector modulation for voltage-source inverters: a unified approach

    Microsoft Academic Search

    H. Pinheiro; F. Botteron; C. Rech; L. Schuch; R. F. Camargo; H. L. Hey; H. A. Griindling; J. R. Pinheiro

    2002-01-01

    This paper presents a unified approach of the space vector modulation for voltage-source inverters. To demonstrate the proposed unified approach, five fundamental inverters topologies are analyzed: single-phase full-bridge, three-phase three-wire, three-phase four-wire, three-phase four-leg and three-phase three-level inverters. Switching vectors, separation and boundary planes in the inverter output space as well as decomposition matrices and possible switching sequences are derived

  9. Eating disorders and multi-level models of emotion: an integrated model.

    PubMed

    Fox, John R E; Power, Michael J

    2009-01-01

    This paper examines the relationship between emotions, depression and eating disorders. Initially, a review is undertaken of the current state of the research and clinical literature with regard to emotional factors in eating disorders. This literature is then integrated within a version of the multi-level model of emotion proposed by Power and Dalgleish. The aim of this paper is to incorporate a basic emotions, multi-modal perspective into developing a new emotions-based model that offers a theoretical understanding of psychological mechanisms in eating disorders. Within the new Schematic Propositional Analogical Associative Representation System model applied to eating disorders, it is argued that the emotions of anger and disgust are of importance in eating disorders and that the eating disorder itself operates as an inhibitor of emotions within the self. It is hoped that the development of a multi-levelled model of eating disorders will allow for the construction of number of specific testable hypotheses that are relevant to future research into the psychological treatment and understanding of eating disorders. PMID:19639647

  10. Multi-Level Discriminative Dictionary Learning With Application to Large Scale Image Classification.

    PubMed

    Shen, Li; Sun, Gang; Huang, Qingming; Wang, Shuhui; Lin, Zhouchen; Wu, Enhua

    2015-10-01

    The sparse coding technique has shown flexibility and capability in image representation and analysis. It is a powerful tool in many visual applications. Some recent work has shown that incorporating the properties of task (such as discrimination for classification task) into dictionary learning is effective for improving the accuracy. However, the traditional supervised dictionary learning methods suffer from high computation complexity when dealing with large number of categories, making them less satisfactory in large scale applications. In this paper, we propose a novel multi-level discriminative dictionary learning method and apply it to large scale image classification. Our method takes advantage of hierarchical category correlation to encode multi-level discriminative information. Each internal node of the category hierarchy is associated with a discriminative dictionary and a classification model. The dictionaries at different layers are learnt to capture the information of different scales. Moreover, each node at lower layers also inherits the dictionary of its parent, so that the categories at lower layers can be described with multi-scale information. The learning of dictionaries and associated classification models is jointly conducted by minimizing an overall tree loss. The experimental results on challenging data sets demonstrate that our approach achieves excellent accuracy and competitive computation cost compared with other sparse coding methods for large scale image classification. PMID:26080049

  11. Design and characterization of water level detector using MW22B Multi-Turn potentiometer

    NASA Astrophysics Data System (ADS)

    Warsito, Pauzi, Gurum A.; Suciyati, Sri W.; Turyani

    2012-06-01

    It has been designed and characterized the water level detector using MW22B Multi-Turn Potentiometer. The electrical angle of potentiometer used has been characterized, that is 3600°±7° and its linearity independent is ±0.25%. The realized system consists of three parts; mechanical system of sensor, signal conditioning circuit and output system. The mechanical system of sensor is destined to convert linearly the value of potentiometer resistance to the water level variation. The signal conditioning consists of analog and digital system especially microcontroller circuit. The value of water level measured is shown on the 2×16 characters LCD. The range of measured water level is 0 - 2.7 m that correspond to the potentiometer resistance range of 100? - 100 k?. The obtained vertical resolution of instrument is about 0.03 m and the error of system is ˜1.11%.

  12. Agent-based model with multi-level herding for complex financial systems.

    PubMed

    Chen, Jun-Jie; Tan, Lei; Zheng, Bo

    2015-01-01

    In complex financial systems, the sector structure and volatility clustering are respectively important features of the spatial and temporal correlations. However, the microscopic generation mechanism of the sector structure is not yet understood. Especially, how to produce these two features in one model remains challenging. We introduce a novel interaction mechanism, i.e., the multi-level herding, in constructing an agent-based model to investigate the sector structure combined with volatility clustering. According to the previous market performance, agents trade in groups, and their herding behavior comprises the herding at stock, sector and market levels. Further, we propose methods to determine the key model parameters from historical market data, rather than from statistical fitting of the results. From the simulation, we obtain the sector structure and volatility clustering, as well as the eigenvalue distribution of the cross-correlation matrix, for the New York and Hong Kong stock exchanges. These properties are in agreement with the empirical ones. Our results quantitatively reveal that the multi-level herding is the microscopic generation mechanism of the sector structure, and provide new insight into the spatio-temporal interactions in financial systems at the microscopic level. PMID:25669427

  13. Modified FGP approach and MATLAB program for solving multi-level linear fractional programming problems

    NASA Astrophysics Data System (ADS)

    Lachhwani, Kailash; Nehra, Suresh

    2015-09-01

    In this paper, we present modified fuzzy goal programming (FGP) approach and generalized MATLAB program for solving multi-level linear fractional programming problems (ML-LFPPs) based on with some major modifications in earlier FGP algorithms. In proposed modified FGP approach, solution preferences by the decision makers at each level are not considered and fuzzy goal for the decision vectors is defined using individual best solutions. The proposed modified algorithm as well as MATLAB program simplifies the earlier algorithm on ML-LFPP by eliminating solution preferences by the decision makers at each level, thereby avoiding difficulties associate with multi-level programming problems and decision deadlock situation. The proposed modified technique is simple, efficient and requires less computational efforts in comparison of earlier FGP techniques. Also, the proposed coding of generalized MATLAB program based on this modified approach for solving ML-LFPPs is the unique programming tool toward dealing with such complex mathematical problems with MATLAB. This software based program is useful and user can directly obtain compromise optimal solution of ML-LFPPs with it. The aim of this paper is to present modified FGP technique and generalized MATLAB program to obtain compromise optimal solution of ML-LFP problems in simple and efficient manner. A comparative analysis is also carried out with numerical example in order to show efficiency of proposed modified approach and to demonstrate functionality of MATLAB program.

  14. In Good Company? A Multi-Study, Multi-Level Investigation of the Effects of Coworker Relationships on Employee Well-Being

    ERIC Educational Resources Information Center

    Simon, Lauren S.; Judge, Timothy A.; Halvorsen-Ganepola, Marie D. K.

    2010-01-01

    Two multi-level studies were conducted to examine the effects of attitudes towards coworkers on daily well-being. Study 1 linked daily levels of coworker satisfaction to job satisfaction and life satisfaction and examined the extent to which job satisfaction mediated the relationship between coworker satisfaction and life satisfaction among 33…

  15. Inverter ratio failure detector

    NASA Technical Reports Server (NTRS)

    Wagner, A. P.; Ebersole, T. J.; Andrews, R. E. (inventors)

    1974-01-01

    A failure detector which detects the failure of a dc to ac inverter is disclosed. The inverter under failureless conditions is characterized by a known linear relationship of its input and output voltages and by a known linear relationship of its input and output currents. The detector includes circuitry which is responsive to the detector's input and output voltages and which provides a failure-indicating signal only when the monitored output voltage is less by a selected factor, than the expected output voltage for the monitored input voltage, based on the known voltages' relationship. Similarly, the detector includes circuitry which is responsive to the input and output currents and provides a failure-indicating signal only when the input current exceeds by a selected factor the expected input current for the monitored output current based on the known currents' relationship.

  16. Inverted Troughs Case Exercise

    NSDL National Science Digital Library

    COMET

    2004-01-29

    This exercise follows the progression of a winter weather event across the Central Plains states beginning 1200 UTC on 7 March 1999. Each forecast question is accompanied by Eta model data and includes a forecast discussion by Phil Schumacher, NWS Sioux Falls, South Dakota. This exercise compliments the Webcast, Inverted Troughs and their Associated Precipitation Regimes, based on a presentation by Phil Schumacher at the MSC Winter Weather Course, December 2002, in Boulder Colorado.

  17. Inverter Modeling For Accurate Energy Predictions Of Tracking HCPV Installations

    NASA Astrophysics Data System (ADS)

    Bowman, J.; Jensen, S.; McDonald, Mark

    2010-10-01

    High efficiency high concentration photovoltaic (HCPV) solar plants of megawatt scale are now operational, and opportunities for expanded adoption are plentiful. However, effective bidding for sites requires reliable prediction of energy production. HCPV module nameplate power is rated for specific test conditions; however, instantaneous HCPV power varies due to site specific irradiance and operating temperature, and is degraded by soiling, protective stowing, shading, and electrical connectivity. These factors interact with the selection of equipment typically supplied by third parties, e.g., wire gauge and inverters. We describe a time sequence model accurately accounting for these effects that predicts annual energy production, with specific reference to the impact of the inverter on energy output and interactions between system-level design decisions and the inverter. We will also show two examples, based on an actual field design, of inverter efficiency calculations and the interaction between string arrangements and inverter selection.

  18. Measurement of Low Level Explosives Reaction in Gauged Multi-Dimensional Steven Impact Tests

    NASA Astrophysics Data System (ADS)

    Niles, A. M.; Forbes, J. W.; Tarver, C. M.; Chidester, S. K.; Garcia, F.; Greenwood, D. W.; Garza, R. G.

    2001-06-01

    The Steven Test was developed to determine relative impact sensitivity of metal encased solid high explosives and be amenable to two-dimensional modeling. Low level reaction thresholds occur at impact velocities below those required for shock initiation. To assist in understanding this test, multi-dimensional gauge techniques utilizing carbon foil and carbon resistor gauges were used to measure pressure and event times. Carbon resistor gauges indicated late time low level reactions 350 ms after projectile impact, creating 0.5-0.6 kb peak shocks centered in PBX 9501 explosives discs. Steven Test calculations based on ignition and growth criteria predict low level reactions occurring at 335 ms which agrees well with experimental data. Additional gauged experiments simulating the Steven Test have been performed and will be discussed. * This work was performed under the auspices of the U.S. Department of Energy by the University of California, Lawrence Livermore National laboratory under contract No. W-7405-Eng-48.

  19. Push pull microfluidics on a multi-level 3D CD

    PubMed Central

    Thio, Tzer Hwai Gilbert; Ibrahim, Fatimah; Al-Faqheri, Wisam; Moebius, Jacob; Khalid, Noor Sakinah; Soin, Norhayati; Kahar, Maria Kahar Bador Abdul; Madou, Marc

    2013-01-01

    A technique known as thermo-pneumatic (TP) pumping is used to pump fluids on a microfluidic compact disc (CD) back towards the CD center against the centrifugal force that pushes liquids from the center to the perimeter of the disc. Trapped air expands in a TP air chamber during heating, and this creates positive pressure on liquids located in chambers connected to that chamber. While the TP air chamber and connecting channels are easy to fabricate in a one-level CD manufacturing technique, this approach provides only one way pumping between two chambers, is real-estate hungry and leads to unnecessary heating of liquids in close proximity to the TP chamber. In this paper, we present a novel TP push and pull pumping method which allows for pumping of liquid in any direction between two connected liquid chambers. To ensure that implementation of TP push and pull pumping also addresses the issue of space and heating challenges, a multi-level 3D CD design is developed, and localized forced convection heating, rather than infra-red (IR) is applied. On a multi-level 3D CD, the TP features are placed on a top level separate from the rest of the microfluidic processes that are implemented on a lower separate level. This approach allows for heat shielding of the microfluidic process levels, and efficient usage of space on the CD for centrifugal handling of liquids. The use of localized forced convection heating, rather than infra-red (IR) or laser heating in earlier implementations allows not only for TP pumping of liquids while the CD is spinning but also makes heat insulation for TP pumping and other fluidic functions easier. To aid in future implementations of TP push and pull pumping on a multi-level 3D CD, study on CD surface heating is also presented. In this contribution, we also demonstrate an advanced application of pull pumping through the implementation of valve-less switch pumping. PMID:23774994

  20. Push pull microfluidics on a multi-level 3D CD.

    PubMed

    Thio, Tzer Hwai Gilbert; Ibrahim, Fatimah; Al-Faqheri, Wisam; Moebius, Jacob; Khalid, Noor Sakinah; Soin, Norhayati; Kahar, Maria Kahar Bador Abdul; Madou, Marc

    2013-08-21

    A technique known as thermo-pneumatic (TP) pumping is used to pump fluids on a microfluidic compact disc (CD) back towards the CD center against the centrifugal force that pushes liquids from the center to the perimeter of the disc. Trapped air expands in a TP air chamber during heating, and this creates positive pressure on liquids located in chambers connected to that chamber. While the TP air chamber and connecting channels are easy to fabricate in a one-level CD manufacturing technique, this approach provides only one way pumping between two chambers, is real-estate hungry and leads to unnecessary heating of liquids in close proximity to the TP chamber. In this paper, we present a novel TP push and pull pumping method which allows for pumping of liquid in any direction between two connected liquid chambers. To ensure that implementation of TP push and pull pumping also addresses the issue of space and heating challenges, a multi-level 3D CD design is developed, and localized forced convection heating, rather than infra-red (IR) is applied. On a multi-level 3D CD, the TP features are placed on a top level separate from the rest of the microfluidic processes that are implemented on a lower separate level. This approach allows for heat shielding of the microfluidic process level, and efficient usage of space on the CD for centrifugal handling of liquids. The use of localized forced convection heating, rather than infra-red (IR) or laser heating in earlier implementations allows not only for TP pumping of liquids while the CD is spinning but also makes heat insulation for TP pumping and other fluidic functions easier. To aid in future implementations of TP push and pull pumping on a multi-level 3D CD, study on CD surface heating is also presented. In this contribution, we also demonstrate an advanced application of pull pumping through the implementation of valve-less switch pumping. PMID:23774994

  1. Multi-level basis selection of wavelet packet decomposition tree for heart sound classification.

    PubMed

    Safara, Fatemeh; Doraisamy, Shyamala; Azman, Azreen; Jantan, Azrul; Abdullah Ramaiah, Asri Ranga

    2013-10-01

    Wavelet packet transform decomposes a signal into a set of orthonormal bases (nodes) and provides opportunities to select an appropriate set of these bases for feature extraction. In this paper, multi-level basis selection (MLBS) is proposed to preserve the most informative bases of a wavelet packet decomposition tree through removing less informative bases by applying three exclusion criteria: frequency range, noise frequency, and energy threshold. MLBS achieved an accuracy of 97.56% for classifying normal heart sound, aortic stenosis, mitral regurgitation, and aortic regurgitation. MLBS is a promising basis selection to be suggested for signals with a small range of frequencies. PMID:24034732

  2. Application of a multi-level grid method to transonic flow calculations

    NASA Technical Reports Server (NTRS)

    South, J. C., Jr.; Brandt, A.

    1976-01-01

    A multi-level grid method was studied as a possible means of accelerating convergence in relaxation calculations for transonic flows. The method employs a hierarchy of grids, ranging from very coarse to fine. The coarser grids are used to diminish the magnitude of the smooth part of the residuals. The method was applied to the solution of the transonic small disturbance equation for the velocity potential in conservation form. Nonlifting transonic flow past a parabolic arc airfoil is studied with meshes of both constant and variable step size.

  3. A multi-level code for metallurgical effects in metal-forming processes

    SciTech Connect

    Taylor, P.A.; Silling, S.A. [Sandia National Labs., Albuquerque, NM (United States). Computational Physics and Mechanics Dept.; Hughes, D.A.; Bammann, D.J.; Chiesa, M.L. [Sandia National Labs., Livermore, CA (United States)

    1997-08-01

    The authors present the final report on a Laboratory-Directed Research and Development (LDRD) project, A Multi-level Code for Metallurgical Effects in metal-Forming Processes, performed during the fiscal years 1995 and 1996. The project focused on the development of new modeling capabilities for simulating forging and extrusion processes that typically display phenomenology occurring on two different length scales. In support of model fitting and code validation, ring compression and extrusion experiments were performed on 304L stainless steel, a material of interest in DOE nuclear weapons applications.

  4. Characterization and simulation of the response of Multi-Pixel Photon Counters to low light levels

    NASA Astrophysics Data System (ADS)

    Vacheret, A.; Barker, G. J.; Dziewiecki, M.; Guzowski, P.; Haigh, M. D.; Hartfiel, B.; Izmaylov, A.; Johnston, W.; Khabibullin, M.; Khotjantsev, A.; Kudenko, Yu.; Kurjata, R.; Kutter, T.; Lindner, T.; Masliah, P.; Marzec, J.; Mineev, O.; Musienko, Yu.; Oser, S.; Retière, F.; Salih, R. O.; Shaikhiev, A.; Thompson, L. F.; Ward, M. A.; Wilson, R. J.; Yershov, N.; Zaremba, K.; Ziembicki, M.

    2011-11-01

    The calorimeter, range detector and active target elements of the T2K near detectors rely on the Hamamatsu Photonics Multi-Pixel Photon Counters (MPPCs) to detect scintillation light produced by charged particles. Detailed measurements of the MPPC gain, afterpulsing, crosstalk, dark noise, and photon detection efficiency for low light levels are reported. In order to account for the impact of the MPPC behavior on T2K physics observables, a simulation program has been developed based on these measurements. The simulation is used to predict the energy resolution of the detector.

  5. Multi-domain, Higher Order Level Set Scheme for 3D Image Segmentation on Ojaswa Sharma 1

    E-print Network

    Texas at Austin, University of

    Multi-domain, Higher Order Level Set Scheme for 3D Image Segmentation on the GPU Ojaswa Sharma 1 os The University of Texas at Austin, USA Abstract Level set method based segmentation provides an effi- cient tool the level set evolution involves linear interpolation to compute derivatives. Bajaj et al. present a higher

  6. Inverted Metamorphic Cell Development: Cooperative Research and Development Final Report, CRADA Number CRD-05-156

    SciTech Connect

    Wanlass, M.

    2012-05-01

    This CRADA targeted technology transfer of the inverted metamorphic multi-junction (IMM) solar cell innovation from NREL to Emcore Photovoltaics. The technology transfer was successfully completed. Additionally, NREL provided materials characterization of solar cell structures produced at Emcore.

  7. Side-by-side planar busbar for voltage source inverters

    Microsoft Academic Search

    Firuz Zare; Gerard Ledwich

    2002-01-01

    Planar busbars are used widely in modern high power inverters and have been shown to provide a good way for minimising stray inductance and overshoot voltage. Planar busbars, which consist of multi-layer copper sheets and dielectric insulators, offer significant advantages such as low impedance, improved thermal characteristic and reduced system cost compared with other interconnection approaches. A common problem of

  8. Multi-level stressor analysis from the DNA/biochemical level to community levels in an urban stream and integrative health response (IHR) assessments.

    PubMed

    Lee, Jae Hoon; Kim, Joon Ha; Oh, Hee-Mock; An, Kwang-Guk

    2013-01-01

    The objectives of this study were to identify multi-level stressors at the DNA/biochemical level to the community level in fish in an urban stream and to develop an integrative health response (IHR) model for ecological health diagnosis. A pristine control site (S (c) ) and an impacted site (S (i) ) were selected from among seven pre-screened sites studied over seven years. Various chemical analyses indicated that nutrient enrichment (Nitrogen, Phosphorus) and organic pollution were significantly greater (t > 8.783, p < 0.01) at the S (i) site compared to the S (c) site. Single-cell gel electrophoresis (comet assays) of DNA-level impairment indicated significantly (t = 5.678, p < 0.01) greater tail intensity, expressed as % tail-DNA, at the S (i) site and genotoxic responses were detected in the downstream reach. Ethoxyresorufin-O-deethylase (EROD) assays, as a physiological bioindicator, were 2.8-fold higher (p < 0.05, NK-test after ANOVA) at the S (i) site. Tissue analysis using a necropsy-based health assessment index (NHAI) showed distinct internal organ disorders in three tissues, i.e., liver, kidney, and gill, at the S (i) site. Population-level analysis using the sentinel species Zacco platypus showed that the regression coefficient (b) was 3.012 for the S (i) site and 2.915 for the S (c) site, indicating population skewness in the downstream reach. Community-level health was impaired at the S (i) site based on an index of biological integrity (IBI), and physical habitat modifications were identified by a qualitative habitat evaluation index (QHEI). Overall, the model values for the integrative health response (IHR), developed using the star plot approach, were 3.22 (80.5%) at the S (c) site and 0.74 (18.5%) at the S (i) site, indicating that, overall, ecological health impairments were evident in the urban reach. Our study was based on multi-level approaches using biological organization and the results suggest that there is a pivotal point of linkage between mechanistic understanding and real ecological consequences of environmental stressors. PMID:23043344

  9. Microseismic mapping of hydraulic fractures using multi-level wireline receivers

    SciTech Connect

    Warpinski, N.R.; Engler, B.P.; Young, C.J. [Sandia National Labs., Albuquerque, NM (United States); Peterson, R.; Branagan, P.T.; Fix, J.E.

    1995-07-01

    Hydraulic fracture diagnostic experiments are being conducted at the GRI/DOE Multi-Site (M-Site) located in the Piceance basin of Colorado. Tests described in this paper use a multi-level advanced-receiver system to build on previous work that showed the advantages of using a single advanced receiver to monitor microseisms. The current test has a four-level receiver system monitoring four separate fracture experiments conducted over a one week period, and includes a velocity tomographic survey and detailed orientation survey. Hydraulic fractures were monitored from an offset well 210 ft away from the treatment well. The results of these monitoring tests show a fracture developing asymmetrically with time, yielding a fracture-wing asymmetry of 2:1. The fracture initially grows within the pay zone to essentially its total length, and then begins to grow upward, and later in time grow downward. Comparison with fracture models gives only a partial agreement in the final size.

  10. Multi-level interconnects for heterojunction bipolar transistor integrated circuit technologies

    SciTech Connect

    Patrizi, G.A.; Lovejoy, M.L.; Schneider, R.P. Jr.; Hou, H.Q. [Sandia National Labs., Albuquerque, NM (United States); Enquist, P.M. [Research Triangle Inst., Research Triangle Park, NC (United States)

    1995-12-31

    Heterojunction bipolar transistors (HBTs) are mesa structures which present difficult planarization problems in integrated circuit fabrication. The authors report a multilevel metal interconnect technology using Benzocyclobutene (BCB) to implement high-speed, low-power photoreceivers based on InGaAs/InP HBTs. Processes for patterning and dry etching BCB to achieve smooth via holes with sloped sidewalls are presented. Excellent planarization of 1.9 {micro}m mesa topographies on InGaAs/InP device structures is demonstrated using scanning electron microscopy (SEM). Additionally, SEM cross sections of both the multi-level metal interconnect via holes and the base emitter via holes required in the HBT IC process are presented. All via holes exhibit sloped sidewalls with slopes of 0.4 {micro}m/{micro}m to 2 {micro}m/{micro}m which are needed to realize a robust interconnect process. Specific contact resistances of the interconnects are found to be less than 6 {times} 10{sup {minus}8} {Omega}cm{sup 2}. Integrated circuits utilizing InGaAs/InP HBTs are fabricated to demonstrate the applicability and compatibility of the multi-level interconnect technology with integrated circuit processing.

  11. Soft-switched PWM high-frequency load-resonant inverter for induction heating cooking appliance

    Microsoft Academic Search

    K. Izaki; I. Hirota; H. Yamashita; H. Omori; S. P. Wang; Md. Jasni

    1997-01-01

    There is a strong demand for high-power multi-burner induction-heating (IH) cooking appliances. It is known that acoustic noise can be generated when conventional frequency-controlled inverters are applied to multi burner IH cooking heaters. In order to eliminate the acoustic noise, this paper presents a prototype voltage-fed quasi-load resonant half-bridge inverter operating at constant frequency variable power (CFVP) regulation scheme which

  12. Study of multi-level characteristics for 3D vertical resistive switching memory.

    PubMed

    Bai, Yue; Wu, Huaqiang; Wu, Riga; Zhang, Ye; Deng, Ning; Yu, Zhiping; Qian, He

    2014-01-01

    Three-dimensional (3D) integration and multi-level cell (MLC) are two attractive technologies to achieve ultra-high density for mass storage applications. In this work, a three-layer 3D vertical AlO?/Ta2O5-x/TaOy resistive random access memories were fabricated and characterized. The vertical cells in three layers show good uniformity and high performance (e.g. >1000X HRS/LRS windows, >10(10) endurance cycles, >10(4) s retention times at 125°C). Meanwhile, four level MLC is demonstrated with two operation strategies, current controlled scheme (CCS) and voltage controlled scheme (VCS). The switching mechanism of 3D vertical RRAM cells is studied based on temperature-dependent transport characteristics. Furthermore, the applicability of CCS and VCS in 3D vertical RRAM array is compared using resistor network circuit simulation. PMID:25047906

  13. Study of Multi-level Characteristics for 3D Vertical Resistive Switching Memory

    PubMed Central

    Bai, Yue; Wu, Huaqiang; Wu, Riga; Zhang, Ye; Deng, Ning; Yu, Zhiping; Qian, He

    2014-01-01

    Three-dimensional (3D) integration and multi-level cell (MLC) are two attractive technologies to achieve ultra-high density for mass storage applications. In this work, a three-layer 3D vertical AlO?/Ta2O5-x/TaOy resistive random access memories were fabricated and characterized. The vertical cells in three layers show good uniformity and high performance (e.g. >1000X HRS/LRS windows, >1010 endurance cycles, >104?s retention times at 125°C). Meanwhile, four level MLC is demonstrated with two operation strategies, current controlled scheme (CCS) and voltage controlled scheme (VCS). The switching mechanism of 3D vertical RRAM cells is studied based on temperature-dependent transport characteristics. Furthermore, the applicability of CCS and VCS in 3D vertical RRAM array is compared using resistor network circuit simulation. PMID:25047906

  14. Measurement of Low Level Explosives Reaction in Gauged Multi-Dimensional Steven Impact Tests

    SciTech Connect

    Niles, A M; Garcia, F; Greenwood, D W; Forbes, J W; Tarver, C M; Chidester, S K; Garza, R G; Swizter, L L

    2001-05-31

    The Steven Test was developed to determine relative impact sensitivity of metal encased solid high explosives and also be amenable to two-dimensional modeling. Low level reaction thresholds occur at impact velocities below those required for shock initiation. To assist in understanding this test, multi-dimensional gauge techniques utilizing carbon foil and carbon resistor gauges were used to measure pressure and event times. Carbon resistor gauges indicated late time low level reactions 200-540 {micro}s after projectile impact, creating 0.39-2.00 kb peak shocks centered in PBX 9501 explosives discs and a 0.60 kb peak shock in a LX-04 disk. Steven Test modeling results, based on ignition and growth criteria, are presented for two PBX 9501 scenarios: one with projectile impact velocity just under threshold (51 m/s) and one with projectile impact velocity just over threshold (55 m/s). Modeling results are presented and compared to experimental data.

  15. Multi-Grained Level of Detail for Rendering Complex Meshes Using a Hierarchical Seamless Texture Atlas

    SciTech Connect

    Niski, K; Purnomo, B; Cohen, J

    2006-11-06

    Previous algorithms for view-dependent level of detail provide local mesh refinements either at the finest granularity or at a fixed, coarse granularity. The former provides triangle-level adaptation, often at the expense of heavy CPU usage and low triangle rendering throughput; the latter improves CPU usage and rendering throughput by operating on groups of triangles. We present a new multiresolution hierarchy and associated algorithms that provide adaptive granularity. This multi-grained hierarchy allows independent control of the number of hierarchy nodes processed on the CPU and the number of triangles to be rendered on the GPU. We employ a seamless texture atlas style of geometry image as a GPU-friendly data organization, enabling efficient rendering and GPU-based stitching of patch borders. We demonstrate our approach on both large triangle meshes and terrains with up to billions of vertices.

  16. The University of Minnesota Pathway Prediction System: multi-level prediction and visualization.

    PubMed

    Gao, Junfeng; Ellis, Lynda B M; Wackett, Lawrence P

    2011-07-01

    The University of Minnesota Pathway Prediction System (UM-PPS, http://umbbd.msi.umn.edu/predict/) is a rule-based system that predicts microbial catabolism of organic compounds. Currently, its knowledge base contains 250 biotransformation rules and five types of metabolic logic entities. The original UM-PPS predicted up to two prediction levels at a time. Users had to choose a predicted product to continue the prediction. This approach provided a limited view of prediction results and heavily relied on manual intervention. The new UM-PPS produces a multi-level prediction within an acceptable time frame, and allows users to view prediction alternatives much more easily as a directed acyclic graph. PMID:21486753

  17. Fusing iris and palmprint at image level for multi-biometrics verification

    NASA Astrophysics Data System (ADS)

    Liu, Jingwang; Hou, Yan; Wang, Jingyan; Li, Yongping; Wang, Quanquan; Man, Jiaju; Xie, Honglan; He, Jianhua

    2011-12-01

    The phase-based image matching is effective for both iris and palm recognition tasks. Hence, we can expect that the approach may be useful for multimodal biometric system having palmprint and iris recognition capabilities. This paper investigates the fusion of palmprint and iris biometric at image level. A new image fusion algorithm named Baud limited image product (BLIP) especially for phase-based image matching is proposed. Based on this, a new multi-biometric fusion scheme at image level that combines BLIP and phase-based image matching is proposed. The effective region of iris and palm images are first extracted respectively, then they are fused into one small size image using BLIP, finally matched with the template using phase-based image matching to get a score. The experimental results show that this new scheme can not only improve the system accuracy performance, but also reduce the memory size used to store the template and time consumed by the matching.

  18. Four quasi-Z-Source inverters

    Microsoft Academic Search

    Joel Anderson; F. Z. Peng

    2008-01-01

    In this paper, theoretical results are shown for several novel inverters. These inverters are similar to the Z-source inverters presented in previous works, but have several advantages, including in some combination; lower component ratings, reduced source stress, reduced component count and simplified control strategies. Like the Z-source inverter, these inverters are particularly suited for applications which require a large range

  19. IEEE IAS 1998 Annual Meeting, St. Louis, Missouri, October 10-15, 1998, pp. 1424-1431. Novel Multilevel Inverter Carrier-Based PWM Methods

    E-print Network

    Tolbert, Leon M.

    as a voltage source inverter. I. INTRODUCTION Multilevel pulse width modulation (PWM) inverters have been as a transformerless voltage source inverter is the diode clamped converter based on the neutral point converter the switching of the active devices in each of the multiple voltage levels in the inverter. An analysis of how

  20. Gender Differences in Public and Private Drinking Contexts: A Multi-Level GENACIS Analysis

    PubMed Central

    Bond, Jason C.; Roberts, Sarah C.M.; Greenfield, Thomas K.; Korcha, Rachael; Ye, Yu; Nayak, Madhabika B.

    2010-01-01

    This multi-national study hypothesized that higher levels of country-level gender equality would predict smaller differences in the frequency of women’s compared to men’s drinking in public (like bars and restaurants) settings and possibly private (home or party) settings. GENACIS project survey data with drinking contexts included 22 countries in Europe (8); the Americas (7); Asia (3); Australasia (2), and Africa (2), analyzed using hierarchical linear models (individuals nested within country). Age, gender and marital status were individual predictors; country-level gender equality as well as equality in economic participation, education, and political participation, and reproductive autonomy and context of violence against women measures were country-level variables. In separate models, more reproductive autonomy, economic participation, and educational attainment and less violence against women predicted smaller differences in drinking in public settings. Once controlling for country-level economic status, only equality in economic participation predicted the size of the gender difference. Most country-level variables did not explain the gender difference in frequency of drinking in private settings. Where gender equality predicted this difference, the direction of the findings was opposite from the direction in public settings, with more equality predicting a larger gender difference, although this relationship was no longer significant after controlling for country-level economic status. Findings suggest that country-level gender equality may influence gender differences in drinking. However, the effects of gender equality on drinking may depend on the specific alcohol measure, in this case drinking context, as well as on the aspect of gender equality considered. Similar studies that use only global measures of gender equality may miss key relationships. We consider potential implications for alcohol related consequences, policy and public health. PMID:20623016

  1. Comparison of traditional inverters and Z-source inverter for fuel cell vehicles

    Microsoft Academic Search

    Miaosen Shen; Alan Joseph; Jin Wang; Fang Z. Peng; D. J. Adams

    2004-01-01

    In This work, three different inverters: traditional PWM inverter, DC\\/DC boosted PWM inverter, and Z-source inverter for fuel cell vehicles were investigated. Total switching device power of each of these inverters was calculated. For purposes of comparison, an example of the total switching device power, requirement of passive components, efficiency, and the constant power speed ratio of the different inverters

  2. Multi-level polysilicon surface-micromachining technology: Applications and issues

    SciTech Connect

    Sniegowski, J.J.

    1996-08-01

    Polysilicon surface micromachining is a technology for manufacturing Micro-Electro-Mechanical Systems (MEMS) which has, as its basis, the manufacturing methods and tool sets used to manufacture the integrated electronic circuit. This paper describes a three-level mechanical-polysilicon surface-micromachining technology and includes a discussion of the advantages of this level of process complexity along with issues which affect device fabrication and performance. Historically, the primary obstacles to multi-level polysilicon fabrication were related to the severe wafer topography generated by the repetition of film depositions and etching. The introduction of Chemical Mechanical Polishing (CMP) to surface micromachining has largely removed these issues and opened significant avenues for device complexity. Several examples of three-level devices with the benefits of CMP are presented. Of primary hindrance to the widespread use of polysilicon surface micromachining, and in particular microactuation mechanisms, are issues related to the device surfaces. The closing discussion examines the potential of several latter and post-fabrication processes to circumvent or to directly alleviate the surface problems.

  3. Invertible Program Restructurings for Continuing Modular Maintenance

    E-print Network

    Paris-Sud XI, Université de

    Invertible Program Restructurings for Continuing Modular Maintenance Julien Cohen ASCOLA team (EMN in main- tenance with invertible program transformations. We illustrate this on the typical Expression problems with our approach. Keywords-modular maintenance; restructuring; invertible pro- gram

  4. Inverted diverticula of the gastrointestinal tract

    Microsoft Academic Search

    Patrick C. Freeny; John H. Walker

    1979-01-01

    Inverted diverticula of the gastrointestinal tract are rare. This paper briefly presents the roentgen findings of an inverted Meckel's diverticulum and is the first reported case of the roentgen appearance of an inverted colonic diverticulum.

  5. Optimization of inverted vector searches

    Microsoft Academic Search

    Chris Buckley; Alan F. Lewit

    1985-01-01

    A simple algorithm is presented for increasing the efficiency of information retrieval searches which are implemented using inverted files. This optimization algorithm employs knowledge about the methods used for weighting document and query terms in order to examine as few inverted lists as possible. An extension to the basic algorithm allows greatly increased performance optimization at a modest cost in

  6. An inverter/controller subsystem optimized for photovoltaic applications

    NASA Technical Reports Server (NTRS)

    Pickrell, R. L.; Merrill, W. C.; Osullivan, G.

    1978-01-01

    Conversion of solar array dc power to ac power stimulated the specification, design, and simulation testing of an inverter/controller subsystem tailored to the photovoltaic power source characteristics. This paper discusses the optimization of the inverter/controller design as part of an overall Photovoltaic Power System (PPS) designed for maximum energy extraction from the solar array. The special design requirements for the inverter/controller include: (1) a power system controller (PSC) to control continuously the solar array operating point at the maximum power level based on variable solar insolation and cell temperatures; and (2) an inverter designed for high efficiency at rated load and low losses at light loadings to conserve energy. It must be capable of operating connected to the utility line at a level set by an external controller (PSC).

  7. Switched Inductor Z-Source Inverter

    Microsoft Academic Search

    Miao Zhu; Kun Yu; Fang Lin Luo

    2010-01-01

    On the basis of the classical Z-source inverter, this paper presents a developed impedance-type power inverter that is termed the switched inductor (SL) Z-source inverter. To enlarge voltage adjustability, the proposed inverter employs a unique SL impedance network to couple the main circuit and the power source. Compared with the classical Z-source inverter, the proposed inverter increases the voltage boost

  8. Data compression using inverted block codes 

    E-print Network

    McClellan, Stan

    1991-01-01

    with Inverted Channel Coding. XIV APC Simulation Results with Noisy Ternary Channel. XV APC Entropy and Rate Simulation Results. XVI Confidence Intervals for APC Symbol Error Simulations. 59 61 62 63 XVII APC Simulation Results with Huffman Code. XVIII... System. Adaptive Predictive Coding System. Reduced Rate APC. 19 Rate-Distortion Bound and Binary Codes. Rate-Distortion Bound and Ternary Codes. Rate-Distortion Bound and 5-ary Codes. 26 26 Classic DPCM System. . 28 2-Level Quantizer. 42 10...

  9. Coaxial inverted geometry transistor having buried emitter

    NASA Technical Reports Server (NTRS)

    Hruby, R. J.; Cress, S. B.; Dunn, W. R. (inventors)

    1973-01-01

    The invention relates to an inverted geometry transistor wherein the emitter is buried within the substrate. The transistor can be fabricated as a part of a monolithic integrated circuit and is particularly suited for use in applications where it is desired to employ low actuating voltages. The transistor may employ the same doping levels in the collector and emitter, so these connections can be reversed.

  10. Multi-Level Phase Change Memory Cells with SiN or Ta2O5 Barrier Layers

    NASA Astrophysics Data System (ADS)

    Gyanathan, Ashvini; Yeo, Yee-Chia

    2012-02-01

    This work compares the effects of SiN and Ta2O5 barrier layers in a multi-level phase change random access memory (PCRAM) cell. The PCRAM cell comprises a phase change material stack between a top and a bottom electrode. The phase change material stack comprises a nitrogen-doped Ge2Sb2Te5 (NGST) layer on top of a thin barrier layer on an undoped GST layer. The thermal conductivity and electrical resistivity of the barrier layer affect multi-level switching performance in terms of endurance as well as power consumption. Extensive electrical characterization was performed on these PCRAM multi-level devices. Thermal analysis was also performed to investigate the thermal efficiency of each barrier layer. It was observed that for a constant barrier layer thickness of 1.5 nm, the endurance of the multi-level device with the SiN barrier layer was better than that with the Ta2O5 barrier layer; however, the multi-level device with the Ta2O5 barrier layer had a lower power consumption than that with the SiN barrier layer.

  11. Multi-level intervention to prevent influenza infections in older low income and minority adults.

    PubMed

    Schensul, Jean J; Radda, Kim; Coman, Emil; Vazquez, Elsie

    2009-06-01

    In this paper we describe a successful multi-level participatory intervention grounded in principles of individual and group empowerment, and guided by social construction theory. The intervention addressed known and persistent inequities in influenza vaccination among African American and Latino older adults, and associated infections, hospitalizations and mortality. It was designed to increase resident ability to make informed decisions about vaccination, and to build internal and external infrastructure to support sustainability over time. The intervention brought a group of social scientists, vaccine researchers, geriatricians, public health nurses, elder services providers and advocates together with senior housing management and activist African American and Latino residents living in public senior housing in a small east coast city. Two buildings of equal size and similar ethnic composition were randomized as intervention and control buildings. Pre and post intervention surveys were conducted in both buildings, measuring knowledge, attitudes and peer norms. Processes and outcomes were documented at four levels: Influenza Strategic Alliance (macro and exo levels), building management (meso level), building resident committee (meso level) and individual residents. The Influenza Strategic Alliance (I.S.A.) provided ongoing resources, information and vaccine; the building management provided economic and other in-kind resources and supported residents to continue flu clinics in the building. The V.I.P. Resident Committee conducted flu campaigns with flu clinics in English and Spanish. The vaccination rate in the intervention building at post test exceeded the study goal of 70% and showed a significant improvement over the control building. The intervention achieved desired outcomes at all four levels and resulted in a significant increase in influenza vaccination, and improvements in pro-vaccination knowledge, beliefs, and understanding of health consequences. PMID:19387822

  12. Multi-level segment analysis: definition and application in turbulent systems

    NASA Astrophysics Data System (ADS)

    Wang, L. P.; Huang, Y. X.

    2015-06-01

    For many complex systems the interaction of different scales is among the most interesting and challenging features. It seems not very successful to extract the physical properties in different scale regimes by the existing approaches, such as the structure-function and Fourier spectrum method. Fundamentally, these methods have their respective limitations, for instance scale mixing, i.e. the so-called infrared and ultraviolet effects. To make improvements in this regard, a new method, multi-level segment analysis (MSA) based on the local extrema statistics, has been developed. Benchmark (fractional Brownian motion) verifications and the important case tests (Lagrangian and two-dimensional turbulence) show that MSA can successfully reveal different scaling regimes which have remained quite controversial in turbulence research. In general the MSA method proposed here can be applied to different dynamic systems in which the concepts of multiscale and multifractality are relevant.

  13. The effects of error management climate and safety communication on safety: a multi-level study.

    PubMed

    Cigularov, Konstantin P; Chen, Peter Y; Rosecrance, John

    2010-09-01

    Work in the construction industry is considered inherently dangerous, despite the technological improvements regarding the safety of work conditions and equipment. To address the urgent need to identify organizational predictors of safety performance and outcomes among construction workers, the present study examined multi-level effects of two important indicators of safety climate, namely contractor error management climate and worker safety communication, on safety behavior, injury, and pain among union construction workers. Data were collected from 235 union construction workers employed by 15 contractors in Midwest and Northwest regions of the United States. Results revealed significant main effects for safety communication and error management climate on safety behaviors and pain, but not on injuries. Our findings suggest that positive safety communication and error management climate are important contributors to improving workplace safety. Specific implications of these results for organizational safety research and practice are discussed. PMID:20538106

  14. Multi-scale dynamical analysis (MSDA) of sea level records versus PDO, AMO, and NAO indexes

    E-print Network

    Scafetta, Nicola

    2013-01-01

    Herein I propose a multi-scale dynamical analysis to facilitate the physical interpretation of tide gauge records. The technique uses graphical diagrams. It is applied to six secular-long tide gauge records representative of the world oceans: Sydney, Pacific coast of Australia; Fremantle, Indian Ocean coast of Australia; New York City, Atlantic coast of USA; Honolulu, U.S. state of Hawaii; San Diego, U.S. state of California; and Venice, Mediterranean Sea, Italy. For comparison, an equivalent analysis is applied to the Pacific Decadal Oscillation (PDO) index and to the Atlantic Multidecadal Oscillation (AMO) index. Finally, a global reconstruction of sea level and a reconstruction of the North Atlantic Oscillation (NAO) index are analyzed and compared: both sequences cover about three centuries from 1700 to 2000. The proposed methodology quickly highlights oscillations and teleconnections among the records at the decadal and multidecadal scales. At the secular time scales tide gauge records present relatively...

  15. A color and texture based multi-level fusion scheme for ethnicity identification

    NASA Astrophysics Data System (ADS)

    Du, Hongbo; Salah, Sheerko Hma; Ahmed, Hawkar O.

    2014-05-01

    Ethnicity identification of face images is of interest in many areas of application. Different from face recognition of individuals, ethnicity identification classifies faces according to the common features of a specific ethnic group. This paper presents a multi-level fusion scheme for ethnicity identification that combines texture features of local areas of a face using local binary patterns with color features using HSV binning. The scheme fuses the decisions from a k-nearest neighbor classifier and a support vector machine classifier into a final identification decision. We have tested the scheme on a collection of face images from a number of publicly available databases. The results demonstrate the effectiveness of the combined features and improvements on accuracy of identification by the fusion scheme over the identification using individual features and other state-of-art techniques.

  16. Multi-level significance of vulnerability indicators. Case study: Eastern Romania

    NASA Astrophysics Data System (ADS)

    Stanga, I. C.; Grozavu, A.

    2012-04-01

    Vulnerability assessment aims, most frequently, to emphasize internal fragility of a system comparing to a reference standard, to similar systems or in relation to a given hazard. Internal fragility, either biophysical or structural, may affect the capacity to predict, to prepare for, to cope with or to recover from a disaster. Thus, vulnerability is linked to resilience and adaptive capacity. From local level to global one, vulnerability factors and corresponding indicators are different and their significance must be tested and validated in a well-structured conceptual and methodological framework. In this paper, the authors aim to show the real vulnerability of rural settlements in Eastern Romania in a multi-level approach. The research area, Tutova Hills, counts about 3421 sq.km and more than 200.000 inhabitants in 421 villages characterized by deficient accessibility, lack of endowments, subsistential agriculture, high pressure on natural environment (especially on forest and soil resources), poverty and aging process of population. Factors that could influence the vulnerability of these rural settlements have been inventoried and assigned into groups through a cluster analysis: habitat and technical urban facilities, infrastructure, economical, social and demographical indicators, environment quality, management of emergency situations etc. Firstly, the main difficulty was to convert qualitative variable in quantitative indicators and to standardize all values to make possible mathematical and statistical processing of data. Secondly, the great variability of vulnerability factors, their different measuring units and their high amplitude of variation require different method of standardization in order to obtain values between zero (minimum vulnerability) and one (maximum vulnerability). Final vulnerability indicators were selected and integrated in a general scheme, according to their significance resulted from an appropriate factor analysis: linear and logistic regression, varimax rotation, multiple-criteria decision analysis, weight of evidence, multi-criteria evaluation method etc. The approach started from the local level which allows a functional and structural analysis and was progressively translated to an upper level and to a spatial analysis. The model shows that changing the level of analysis diminishes the functional significance of some indicators and increases the capacity of discretization in the case of others, highlighting the spatial and functional complexity of vulnerability.

  17. The bidirectional Z-source inverter for energy storage application

    Microsoft Academic Search

    Jacek Rabkowski

    2007-01-01

    Paper describes development of a three-phase bidirectional Z-source inverter (ZSI) interfacing an energy storage and supply network. Idea of bidirectional operation of ZSI is presented and simply solution of the capacitor voltage over boost problem is proposed. Issue of correct selection of voltage levels and minimum storage voltage for grid-connected inverter is discussed. Selection of the suitable PWM method and

  18. Novel space vector based current controllers for PWM-inverters

    Microsoft Academic Search

    M. P. Kazmierkowski; M. A. Dzieniakowski; W. Sulkowski

    1991-01-01

    Two novel, simple control strategies for current-controlled pulse-width modulated (PWM) transistor inverters are presented. Both methods are based on the three-level hysteresis comparators which select appropriate inverter output voltage vectors via a switching electrically programmable read-only memory (EPROM) table. The first controller works with current components represented in a stationary coordinate system (AC components) and the second with components represented

  19. Multilevel conversion: high voltage choppers and voltage-source inverters

    Microsoft Academic Search

    T. A. Meynard; H. Foch

    1992-01-01

    The authors discuss high-voltage power conversion. Conventional series connection and three-level voltage source inverter techniques are reviewed and compared. A novel versatile multilevel commutation cell is introduced: it is shown that this topology is safer and more simple to control, and delivers purer output waveforms. The authors show how this technique can be applied to either choppers or voltage-source inverters

  20. Simple Multi-level Microchannel Fabrication by Pseudo-Grayscale Backside Diffused Light Lithography

    PubMed Central

    Lai, David; Labuz, Joseph M.; Kim, Jiwon; Luker, Gary D.; Shikanov, Ariella; Takayama, Shuichi

    2014-01-01

    Photolithography of multi-level channel features in microfluidics is laborious and/or costly. Grayscale photolithography is mostly used with positive photoresists and conventional front side exposure, but the grayscale masks needed are generally costly and positive photoresists are not commonly used in microfluidic rapid prototyping. Here we introduce a simple and inexpensive alternative that uses pseudo-grayscale (pGS) photomasks in combination with backside diffused light lithography (BDLL) and the commonly used negative photoresist, SU-8. BDLL can produce smooth multi-level channels of gradually changing heights without use of true grayscale masks because of the use of diffused light. Since the exposure is done through a glass slide, the photoresist is cross-linked from the substrate side up enabling well-defined and stable structures to be fabricated from even unspun photoresist layers. In addition to providing unique structures and capabilities, the method is compatible with the “garage microfluidics” concept of creating useful tools at low cost since pGS BDLL can be performed with the use of only hot plates and a UV transilluminator: equipment commonly found in biology labs. Expensive spin coaters or collimated UV aligners are not needed. To demonstrate the applicability of pGS BDLL, a variety of weir-type cell traps were constructed with a single UV exposure to separate cancer cells (MDA-MB-231, 10-15 ?m in size) from red blood cells (RBCs, 2-8 ?m in size) as well as follicle clusters (40-50 ?m in size) from cancer cells (MDA-MB-231, 10-15 ?m in size). PMID:24976950

  1. Multi-level femoral morphology and mechanical properties of rats of different ages.

    PubMed

    Zhang, Rui; Gong, He; Zhu, Dong; Ma, Renshi; Fang, Juan; Fan, Yobo

    2015-07-01

    A macro-micro-nano-multi-level study was conducted to explore age-related structural and mechanical properties of bone, as well as the effects of aging on bone properties. A total of 70 male Wistar rats were used, ranging in the ages of 1, 3, 5, 7, 9, 11, 14, 15, 16, and 17months (n=7/age group). After micro-computed tomography (CT) scanning, longitudinal cortical bone specimens with a length of 5mm were cut along the femoral shaft axis from left femur shafts for mechanical testing, and the cross-sectional areas were measured. The macro-mechanical properties obtained in mechanical testing and microarchitecture parameters measured by micro-CT were significantly correlated with the animal age (r(2)=0.96, p<0.001). Scanning electron microscopy was used for detecting the microarchitecture features of the fractured surfaces, which exhibited age-related plate-fibrous-mixed fibrous-plate texture, resulting in changes in macro-mechanical properties (r(2)>0.90, p<0.001). The mineral phase of the left femoral shaft and head was analyzed by atomic force microscopy. Longitudinal and transverse trabecular bone tissues, as well as longitudinal cortical bone tissue, were used for nanoindentation test, and the chemical composition was evaluated by quantitative chemical analyses. The correlations between mineral content and bone material properties (i.e., elastic properties of the bone tissue and size and roughness of bone mineral grains) were highly significant (r>0.95, p<0.001). Multi-level femur morphology, mechanical property, and mineral content were significantly correlated with the animal age. The correlations between bone mineral content and bone material morphological and mechanical properties may partly explain the increase in bone fragility with aging, which will provide a theoretical basis for the investigation of age-related bone properties in clinics. PMID:25857690

  2. Transient plasmon-like modes in multi-level quantum emitter systems

    NASA Astrophysics Data System (ADS)

    Gentile, Martin J.; Barnes, William L.

    2014-09-01

    We model a nanoparticle of organic dye molecules as an ensemble of multi-level quantum systems in order to determine the conditions necessary to yield temporal optical field enhancement for different probe energies. By utilizing a time-dependent density-matrix approach and by examination of the role played by both radiative and non-radiative decay processes between energy levels, we explore how optical pump and probe fields may be used to control the permittivity of the nanoparticle as a function of time. When an appropriate value of the permittivity occurs, a plasmon-like mode will be produced. In this work, we investigate systems in which these plasmon-like modes can be generated at probe energies detuned from the atomic transitions and sustained for timescales dependent on the lifetime of a meta-stable level in our system. Our results suggest that these plasmon-like modes may generate temporal optical field enhancement and that such nanostructures open a new realm in nanophotonics in which transient behaviour can lead to phenomena that cannot be attained in the steady-state regime.

  3. Multi-level machine learning prediction of protein–protein interactions in Saccharomyces cerevisiae

    PubMed Central

    Zubek, Julian; Tatjewski, Marcin; Boniecki, Adam; Mnich, Maciej; Basu, Subhadip

    2015-01-01

    Accurate identification of protein–protein interactions (PPI) is the key step in understanding proteins’ biological functions, which are typically context-dependent. Many existing PPI predictors rely on aggregated features from protein sequences, however only a few methods exploit local information about specific residue contacts. In this work we present a two-stage machine learning approach for prediction of protein–protein interactions. We start with the carefully filtered data on protein complexes available for Saccharomyces cerevisiae in the Protein Data Bank (PDB) database. First, we build linear descriptions of interacting and non-interacting sequence segment pairs based on their inter-residue distances. Secondly, we train machine learning classifiers to predict binary segment interactions for any two short sequence fragments. The final prediction of the protein–protein interaction is done using the 2D matrix representation of all-against-all possible interacting sequence segments of both analysed proteins. The level-I predictor achieves 0.88 AUC for micro-scale, i.e., residue-level prediction. The level-II predictor improves the results further by a more complex learning paradigm. We perform 30-fold macro-scale, i.e., protein-level cross-validation experiment. The level-II predictor using PSIPRED-predicted secondary structure reaches 0.70 precision, 0.68 recall, and 0.70 AUC, whereas other popular methods provide results below 0.6 threshold (recall, precision, AUC). Our results demonstrate that multi-scale sequence features aggregation procedure is able to improve the machine learning results by more than 10% as compared to other sequence representations. Prepared datasets and source code for our experimental pipeline are freely available for download from: http://zubekj.github.io/mlppi/ (open source Python implementation, OS independent). PMID:26157620

  4. Transmission of a Single Plasmon Interacting with Multi-Level Quantum Dots Systems Coupled to Plasmonic Waveguide

    E-print Network

    Kim, Nam-Chol; Choe, Chung-Il

    2015-01-01

    We theoretically investigated the transmission properties of a single plasmon interacting with two-level quantum dots (QDs) and a V-type three-level QD, coupled to plasmonic waveguide, respectively. We showed that the transmission and reflection of a single plasmon interacting with multi-level QDs can be switched on or off by controlling the detuning and changing the interparticle distances between the QDs.

  5. Dispersion retrieval from multi-level ultra-deep reactive-ion-etched microstructures for terahertz slow-wave circuits

    SciTech Connect

    Baik, Chan-Wook, E-mail: cw.baik@samsung.com; Young Ahn, Ho; Kim, Yongsung; Lee, Jooho; Hong, Seogwoo; Hee Choi, Jun; Kim, Sunil; Hun Lee, Sang; Min Kim, Jong; Hwang, Sungwoo [Samsung Advanced Institute of Technology, Yongin 446-712 (Korea, Republic of); Yeon Jun, So; Yu, SeGi [Department of Physics, Hankuk University of Foreign Studies, Yongin 449-791 (Korea, Republic of); Lawrence Ives, R. [Calabazas Creek Research, Inc., San Mateo, California 94404-1010 (United States)

    2014-01-13

    A multi-level microstructure is proposed for terahertz slow-wave circuits, with dispersion relation retrieved by scattering parameter measurements. The measured return loss shows strong resonances above the cutoff with negligible phase shifts compared with finite element analysis. Splitting the circuit into multi levels enables a low aspect ratio configuration that alleviates the loading effect of deep-reactive-ion etching on silicon wafers. This makes it easier to achieve flat-etched bottom and smooth sidewall profiles. The dispersion retrieved from the measurement, therefore, corresponds well to the theoretical estimation. The result provides a straightforward way to the precise determination of dispersions in terahertz vacuum electronics.

  6. An improved carrier-based SVPWM method using leg voltage redundancies in generalized cascaded multilevel inverter topology

    Microsoft Academic Search

    Dae-Wook Kang; Yo-Han Lee; Bum-Seok Suh; Chang-Ho Choi; Dong-Seok Hyun

    2003-01-01

    The carrier-based space vector pulse width modulation (SVPWM), which is considered as simple and efficient PWM technology, can be also used in multilevel inverters. The method was originally designed for the two-level inverter and developed to the diode-clamped multilevel inverter structure. However it may be noted that it also causes bad switch utilization in cascaded multilevel inverters. This paper introduces

  7. Multi-level gene/MiRNA feature selection using deep belief nets and active learning.

    PubMed

    Ibrahim, Rania; Yousri, Noha A; Ismail, Mohamed A; El-Makky, Nagwa M

    2014-01-01

    Selecting the most discriminative genes/miRNAs has been raised as an important task in bioinformatics to enhance disease classifiers and to mitigate the dimensionality curse problem. Original feature selection methods choose genes/miRNAs based on their individual features regardless of how they perform together. Considering group features instead of individual ones provides a better view for selecting the most informative genes/miRNAs. Recently, deep learning has proven its ability in representing the data in multiple levels of abstraction, allowing for better discrimination between different classes. However, the idea of using deep learning for feature selection is not widely used in the bioinformatics field yet. In this paper, a novel multi-level feature selection approach named MLFS is proposed for selecting genes/miRNAs based on expression profiles. The approach is based on both deep and active learning. Moreover, an extension to use the technique for miRNAs is presented by considering the biological relation between miRNAs and genes. Experimental results show that the approach was able to outperform classical feature selection methods in hepatocellular carcinoma (HCC) by 9%, lung cancer by 6% and breast cancer by around 10% in F1-measure. Results also show the enhancement in F1-measure of our approach over recently related work in [1] and [2]. PMID:25570858

  8. Image accuracy and representational enhancement through low-level, multi-sensor integration techniques

    SciTech Connect

    Baker, J.E.

    1994-09-01

    Multi-Sensor Integration (MSI) is the combining of data and information from more than one source in order to generate a more reliable and consistent representation of the environment. The need for MSI derives largely from basic ambiguities inherent in our current sensor imaging technologies. These ambiguities exist as long as the mapping from reality to image is not 1-to-1. That is, if different {open_quotes}realities{close_quotes} lead to identical images, a single image cannot reveal the particular reality which was the truth. MSI techniques attempt to resolve some of these ambiguities by appropriately coupling complementary images to eliminate possible inverse mappings. What constitutes the best MSI technique is dependent on the given application domain, available sensors, and task requirements. MSI techniques can be divided into three categories based on the relative information content of the original images with that of the desired representation: (1) {open_quotes}detail enhancement,{close_quotes} wherein the relative information content of the original images is less rich than the desired representation; (2) {open_quotes}data enhancement,{close_quotes} wherein the MSI techniques are concerned with improving the accuracy of the data rather than either increasing or decreasing the level of detail; and (3) {open_quotes}conceptual enhancement,{close_quotes} wherein the image contains more detail than is desired, making it difficult to easily recognize objects of interest. In conceptual enhancement one must group pixels corresponding to the same conceptual object and thereby reduce the level of extraneous detail.

  9. A spectral-Lagrangian Boltzmann solver for a multi-energy level gas

    SciTech Connect

    Munafò, Alessandro, E-mail: munafo@vki.ac.be [Aeronautics and Aerospace Department, von Karman Institute for Fluid Dynamics, Chaussée de Waterloo 72, 1640 Rhode-Saint-Genèse (Belgium); Haack, Jeffrey R., E-mail: haack@math.utexas.edu [Department of Mathematics, The University of Texas at Austin, 201 E. 24th Street, Austin, TX 78712 (United States); Gamba, Irene M., E-mail: gamba@math.utexas.edu [Department of Mathematics, The University of Texas at Austin, 201 E. 24th Street, Austin, TX 78712 (United States); The Institute for Computational Engineering and Sciences (ICES), The University of Texas at Austin, 201 E. 24th Street, Austin, TX 78712 (United States); Magin, Thierry E., E-mail: magin@vki.ac.be [Aeronautics and Aerospace Department, von Karman Institute for Fluid Dynamics, Chaussée de Waterloo 72, 1640 Rhode-Saint-Genèse (Belgium)

    2014-05-01

    In this paper a spectral-Lagrangian method is proposed for the full, non-linear Boltzmann equation for a multi-energy level gas typical of a hypersonic re-entry flow. Internal energy levels are treated as separate species and inelastic collisions (leading to internal energy excitation and relaxation) are accounted for. The formulation developed can also be used for the case of a gas mixture made of monatomic gases without internal energy (where only elastic collisions occur). The advantage of the spectral-Lagrangian method lies in the generality of the algorithm in use for the evaluation of the elastic and inelastic collision operators, as well as the conservation of mass, momentum and energy during collisions. The latter is realized through the solution of constrained optimization problems. The computational procedure is based on the Fourier transform of the partial elastic and inelastic collision operators and exploits the fact that these can be written as weighted convolutions in Fourier space with no restriction on the cross-section model. The feasibility of the proposed approach is demonstrated through numerical examples for both space homogeneous and in-homogeneous problems. Computational results are compared with those obtained by means of the DSMC method in order to assess the accuracy of the proposed spectral-Lagrangian method.

  10. Multi-Level Kinetic Model of mRNA Delivery via Transfection of Lipoplexes

    PubMed Central

    Ligon, Thomas S.; Leonhardt, Carolin; Rädler, Joachim O.

    2014-01-01

    Recent work on the use of mRNA lipoplexes for gene delivery demonstrates the need for a mathematical model that simulates and predicts kinetics and transfection efficiency. The small copy numbers involved make it necessary to use stochastic models and include statistical analysis of the variation observed in the experimental data. The modeling requirements are further complicated by the multi-level nature of the problem, where mRNA molecules are contained in lipoplexes, which are in turn contained in endosomes, where each of these entities displays a behavior of its own. We have created a mathematical model that reproduces both the time courses and the statistical variance observed in recent experiments using single-cell tracking of GFP expression after transfection. By applying a few key simplifications and assumptions, we have limited the number of free parameters to five, which we optimize to match five experimental determinants by means of a simulated annealing algorithm. The models demonstrate the need for modeling of nested species in order to reproduce the shape of the dose-response and expression-level curves. PMID:25237886

  11. Multi-level tree analysis of pulmonary artery/vein trees in non-contrast CT images

    NASA Astrophysics Data System (ADS)

    Gao, Zhiyun; Grout, Randall W.; Hoffman, Eric A.; Saha, Punam K.

    2012-02-01

    Diseases like pulmonary embolism and pulmonary hypertension are associated with vascular dystrophy. Identifying such pulmonary artery/vein (A/V) tree dystrophy in terms of quantitative measures via CT imaging significantly facilitates early detection of disease or a treatment monitoring process. A tree structure, consisting of nodes and connected arcs, linked to the volumetric representation allows multi-level geometric and volumetric analysis of A/V trees. Here, a new theory and method is presented to generate multi-level A/V tree representation of volumetric data and to compute quantitative measures of A/V tree geometry and topology at various tree hierarchies. The new method is primarily designed on arc skeleton computation followed by a tree construction based topologic and geometric analysis of the skeleton. The method starts with a volumetric A/V representation as input and generates its topologic and multi-level volumetric tree representations long with different multi-level morphometric measures. A new recursive merging and pruning algorithms are introduced to detect bad junctions and noisy branches often associated with digital geometric and topologic analysis. Also, a new notion of shortest axial path is introduced to improve the skeletal arc joining two junctions. The accuracy of the multi-level tree analysis algorithm has been evaluated using computer generated phantoms and pulmonary CT images of a pig vessel cast phantom while the reproducibility of method is evaluated using multi-user A/V separation of in vivo contrast-enhanced CT images of a pig lung at different respiratory volumes.

  12. Carrier Density and Compensation in Semiconductors with Multi Dopants and Multi Transition Energy Levels: The Case of Cu Impurity in CdTe

    SciTech Connect

    Wei, S. H.; Ma, J.; Gessert, T. A.; Chin, K. K.

    2011-01-01

    Doping is one of the most important issues in semiconductor physics. The charge carrier generated by doping can profoundly change the properties of semiconductors and their performance in optoelectronic device applications, such as solar cells. Using detailed balance theory and first-principles calculated defect formation energies and transition energy levels, we derive general formulae to calculate carrier density for semiconductors with multi dopants and multi transition energy levels. As an example, we studied CdTe doped with Cu, in which V{sub Cd}, Cu{sub Cd}, and Cu{sub i} are the dominant defects/impurities. We show that in this system, when Cu concentration increases, the doping properties of the system can change from a poor p-type, to a poorer p-type, to a better p-type, and then to a poor p-type again, in good agreement with experimental observation of CdTe-based solar cells.

  13. Efficient compact watt-level deep-ultraviolet laser generated from a multi-kHz Q-switched diode-pumped

    E-print Network

    Kung, Andy

    Efficient compact watt-level deep-ultraviolet laser generated from a multi-kHz Q-switched diode from a multi-kHz diode-pumped multi-longitudinal- mode Q-switched Nd:YAG laser by fourth harmonic­4], or a tightly focused, relatively complicated arrange- ment for compact diode-pumped systems [5­8]. Serious

  14. General Analysis of Three-Phase Inverters

    Microsoft Academic Search

    Kalman R. Jardan; S. B. Dewan; Gordon R. Slemon

    1969-01-01

    A method of analysis for three-phase inverters is described. The method is based on Park vectors [1], [2] and predicts the waveforms of inverter quantities under various load conditions. The procedure discussed can be used to determine the commutation sequence of a pulsewidth modulated inverter. The current distribution of the inverter can be obtained from the current vector. The vectors

  15. Design methodologies for soft switched inverters

    Microsoft Academic Search

    D. M. Divan; G. Venkataramanan; R. W. De Doncker

    1988-01-01

    A detailed design methodology is presented for soft switched inverters. The actively clamped resonant DC link inverter and the resonant pole inverter are taken as illustrative design examples with a detailed enumeration of component design rules, switching loss calculations, and system optimization. The soft-switched circuits are then compared with the conventional hard-switched voltage-sourced inverter under identical load conditions

  16. Sensitive Multi-Species Emissions Monitoring: Infrared Laser-Based Detection of Trace-Level Contaminants.

    SciTech Connect

    Steill, Jeffrey D

    2015-01-01

    This report summarizes our development of spectroscopic chemical analysis techniques and spectral modeling for trace-gas measurements of highly-regulated low-concentration species present in flue gas emissions from utility coal boilers such as HCl under conditions of high humidity. Detailed spectral modeling of the spectroscopy of HCl and other important combustion and atmospheric species such as H 2 O, CO 2 , N 2 O, NO 2 , SO 2 , and CH 4 demonstrates that IR-laser spectroscopy is a sensitive multi-component analysis strategy. Experimental measurements from techniques based on IR laser spectroscopy are presented that demonstrate sub-ppm sensitivity levels to these species. Photoacoustic infrared spectroscopy is used to detect and quantify HCl at ppm levels with extremely high signal-to-noise even under conditions of high relative humidity. Additionally, cavity ring-down IR spectroscopy is used to achieve an extremely high sensitivity to combustion trace gases in this spectral region; ppm level CH 4 is one demonstrated example. The importance of spectral resolution in the sensitivity of a trace-gas measurement is examined by spectral modeling in the mid- and near-IR, and efforts to improve measurement resolution through novel instrument development are described. While previous project reports focused on benefits and complexities of the dual-etalon cavity ring-down infrared spectrometer, here details on steps taken to implement this unique and potentially revolutionary instrument are described. This report also illustrates and critiques the general strategy of IR- laser photodetection of trace gases leading to the conclusion that mid-IR laser spectroscopy techniques provide a promising basis for further instrument development and implementation that will enable cost-effective sensitive detection of multiple key contaminant species simultaneously.

  17. Image accuracy and representational enhancement through low-level, multi-sensor integration techniques

    SciTech Connect

    Baker, J.E.

    1993-05-01

    Multi-Sensor Integration (MSI) is the combining of data and information from more than one source in order to generate a more reliable and consistent representation of the environment. The need for MSI derives largely from basic ambiguities inherent in our current sensor imaging technologies. These ambiguities exist as long as the mapping from reality to image is not 1-to-1. That is, if different 44 realities'' lead to identical images, a single image cannot reveal the particular reality which was the truth. MSI techniques can be divided into three categories based on the relative information content of the original images with that of the desired representation: (1) detail enhancement,'' wherein the relative information content of the original images is less rich than the desired representation; (2) data enhancement,'' wherein the MSI techniques axe concerned with improving the accuracy of the data rather than either increasing or decreasing the level of detail; and (3) conceptual enhancement,'' wherein the image contains more detail than is desired, making it difficult to easily recognize objects of interest. In conceptual enhancement one must group pixels corresponding to the same conceptual object and thereby reduce the level of extraneous detail. This research focuses on data and conceptual enhancement algorithms. To be useful in many real-world applications, e.g., autonomous or teleoperated robotics, real-time feedback is critical. But, many MSI/image processing algorithms require significant processing time. This is especially true of feature extraction, object isolation, and object recognition algorithms due to their typical reliance on global or large neighborhood information. This research attempts to exploit the speed currently available in state-of-the-art digitizers and highly parallel processing systems by developing MSI algorithms based on pixel rather than global-level features.

  18. Image accuracy and representational enhancement through low-level, multi-sensor integration techniques

    SciTech Connect

    Baker, J.E.

    1993-05-01

    Multi-Sensor Integration (MSI) is the combining of data and information from more than one source in order to generate a more reliable and consistent representation of the environment. The need for MSI derives largely from basic ambiguities inherent in our current sensor imaging technologies. These ambiguities exist as long as the mapping from reality to image is not 1-to-1. That is, if different 44 realities`` lead to identical images, a single image cannot reveal the particular reality which was the truth. MSI techniques can be divided into three categories based on the relative information content of the original images with that of the desired representation: (1) ``detail enhancement,`` wherein the relative information content of the original images is less rich than the desired representation; (2) ``data enhancement,`` wherein the MSI techniques axe concerned with improving the accuracy of the data rather than either increasing or decreasing the level of detail; and (3) ``conceptual enhancement,`` wherein the image contains more detail than is desired, making it difficult to easily recognize objects of interest. In conceptual enhancement one must group pixels corresponding to the same conceptual object and thereby reduce the level of extraneous detail. This research focuses on data and conceptual enhancement algorithms. To be useful in many real-world applications, e.g., autonomous or teleoperated robotics, real-time feedback is critical. But, many MSI/image processing algorithms require significant processing time. This is especially true of feature extraction, object isolation, and object recognition algorithms due to their typical reliance on global or large neighborhood information. This research attempts to exploit the speed currently available in state-of-the-art digitizers and highly parallel processing systems by developing MSI algorithms based on pixel rather than global-level features.

  19. Bi-level multi-source learning for heterogeneous block-wise missing data.

    PubMed

    Xiang, Shuo; Yuan, Lei; Fan, Wei; Wang, Yalin; Thompson, Paul M; Ye, Jieping

    2014-11-15

    Bio-imaging technologies allow scientists to collect large amounts of high-dimensional data from multiple heterogeneous sources for many biomedical applications. In the study of Alzheimer's Disease (AD), neuroimaging data, gene/protein expression data, etc., are often analyzed together to improve predictive power. Joint learning from multiple complementary data sources is advantageous, but feature-pruning and data source selection are critical to learn interpretable models from high-dimensional data. Often, the data collected has block-wise missing entries. In the Alzheimer's Disease Neuroimaging Initiative (ADNI), most subjects have MRI and genetic information, but only half have cerebrospinal fluid (CSF) measures, a different half has FDG-PET; only some have proteomic data. Here we propose how to effectively integrate information from multiple heterogeneous data sources when data is block-wise missing. We present a unified "bi-level" learning model for complete multi-source data, and extend it to incomplete data. Our major contributions are: (1) our proposed models unify feature-level and source-level analysis, including several existing feature learning approaches as special cases; (2) the model for incomplete data avoids imputing missing data and offers superior performance; it generalizes to other applications with block-wise missing data sources; (3) we present efficient optimization algorithms for modeling complete and incomplete data. We comprehensively evaluate the proposed models including all ADNI subjects with at least one of four data types at baseline: MRI, FDG-PET, CSF and proteomics. Our proposed models compare favorably with existing approaches. PMID:23988272

  20. Switched Capacitor Snubber-Assisted Zero Current Soft Switching PWM High Frequency Inverter with Two-Lossless Inductive Snubbers

    Microsoft Academic Search

    M. H. Hashem; N. A. Ahmed; E. Hiraki; T. Ahmed; K. Fathi; Hyun-Woo Lee; M. Nakaoka

    2005-01-01

    In this paper, a novel type of auxiliary switched capacitor assisted edge resonant soft switching PWM series load resonant high frequency inverter with two auxiliary edge resonant lossless inductor snubbers is proposed for small consumer induction heating appliances. The operation principle of this high frequency inverter is described using the switching mode equivalent circuits. This newly developed multi resonant high

  1. Comparison of Traditional Inverters and Z Source Inverter for Fuel Cell Vehicles

    Microsoft Academic Search

    Miaosen Shen; Alan Joseph; Jin Wang; Fang Z. Peng; Donald J. Adams

    2007-01-01

    In this paper, three different inverters: conventional pulsewidth modulation (PWM) inverter, dc-dc boosted PWM inverter, and Z-source inverter were investigated and compared for fuel cell vehicle application. Total switching device power, passive components requirement, and constant power speed ratio of each of these inverters were calculated. For purposes of comparison, an example of the total switching device power, requirement of

  2. A novel hysteresis current controller for multilevel single phase voltage source inverters

    Microsoft Academic Search

    G. H. Bode; D. N. Zmood; P. C. Loh; D. G. Holmes

    2001-01-01

    The application and benefits of hysteresis current control for two level voltage source inverters are well understood, but the extension of the strategy to multilevel inverters is much less established. Previous approaches have used either multiple hysteresis bands or a time based lockout strategy to decide when to switch to successive voltage levels, but these approaches are either complex, and\\/or

  3. Studying Directory Access Patterns via Reuse Distance Analysis and Evaluating Their Impact on Multi-Level Directory Caches

    E-print Network

    Yeung, Donald

    Studying Directory Access Patterns via Reuse Distance Analysis and Evaluating Their Impact on Multi-Level Directory Caches Minshu Zhao, and Donald Yeung Department of Electrical and Computer Engineering University core count. One of the key limiters to scaling will be the on-chip directory cache. Our work

  4. Putting Poverty in Political Context: A Multi-Level Analysis of Adult Poverty across 18 Affluent Democracies

    ERIC Educational Resources Information Center

    Brady, David; Fullerton, Andrew S.; Cross, Jennifer Moren

    2009-01-01

    Our study analyzes how political context, embodied by the welfare state and Leftist political actors, shapes individual poverty. Using the Luxembourg Income Study, we conduct a multi-level analysis of working-aged adult poverty across 18 affluent Western democracies. Our index of welfare generosity has a negative effect on poverty net of…

  5. Nicotine, acetanilide and urea multi-level 2 N-abundance reference materials for continuous-flow

    E-print Network

    Nicotine, acetanilide and urea multi-level 2 H-, 13 C- and 15 N-abundance reference materials the development and quality testing of (i) four nicotine laboratory reference materials for on-line (i nicotines for oxidative C, N gas chroma- tography-combustion-isotope ratio mass-spectrometry (GC

  6. The Use of Observability and External Don't Cares for the Simplification of MultiLevel Networks

    Microsoft Academic Search

    Hamid Savoj; Robert K. Brayton

    1990-01-01

    We give an algorithm for computing subsets of observability don't cares at the nodes of a multi-level Boolean network. These subsets are based on an extension of the methods introduced in [4] for computing compatible sets of permissible functions (CSPF's) at the nodes of networks composed of NOR gates. The extensions presented are in four directions; an arbitrary logic function

  7. Multicarrier PWM strategies for multilevel inverters

    Microsoft Academic Search

    Brendan Peter McGrath; Donald Grahame Holmes

    2002-01-01

    Analytical solutions of pulsewidth-modulation (PWM) strategies for multilevel inverters are used to identify that alternative phase opposition disposition PWM for diode-clamped inverters produces the same harmonic performance as phase-shifted carrier PWM for cascaded inverters, and hybrid PWM for hybrid inverters, when the carrier frequencies are set to achieve the same number of inverter switch transitions over each fundamental cycle. Using

  8. SUPERVISED AND FOREST TYPE-SPECIFIC MULTI-SCALE SEGMENTATION FOR A ONE-LEVEL-REPRESENTATION OF SINGLE TREES

    Microsoft Academic Search

    D. Tiede

    In this paper a supervised approach for the object building \\/ segmentation process utilizing a priori knowledge about the specific scale domain of the target features is proposed. One premise was that the result should finally represent the entire scene content in a spatially contiguous one-level-representation (OLR, Lang & Langanke, 2006). High-level segmentation and pre-classification of multi-spectral line scanner data

  9. Comparison of TID Response and SEE Characterization of Single and Multi Level High Density NAND Flash Memories

    NASA Technical Reports Server (NTRS)

    Irom, Farokh; Nguyen, Duc N.; Harboe-Sorensen, Reno; Virtanen, Ari

    2009-01-01

    Heavy ion single-event measurements and TID response for 8Gb commercial NAND flash memories are reported. Radiation results of multi-level flash technology are compared with results from single-level flash technology. In general, these commercial high density memories appear to be much less susceptible to SEE and have better TID response compared to older generations of flash memories. The charge pump survived up to 600 krads.

  10. Device, circuit and system-level analysis of noise in multi-bit phase-change memory

    Microsoft Academic Search

    G. F. Close; U. Frey; M. Breitwisch; H. L. Lung; C. Lam; C. Hagleitner; E. Eleftheriou

    2010-01-01

    We present a comprehensive investigation of noise in multi-bit phase-change memory (PCM). The impact of noise on data integrity was quantified with a combination of experiments and simulations. A prototype chip was fabricated to support our system-level analysis, which shows that a raw bit error rate of ~10-4 is achievable at 3-bit\\/cell. At the circuit level, we identified the bit

  11. Computation of Dendritic Growth with Level Set Model Using a Multi-Mesh Adaptive Finite Element Method

    Microsoft Academic Search

    Yana Di; Ruo Li

    2009-01-01

    In this paper, we propose an efficient multi-mesh h-adaptive algorithm to solve the level set model of dendritic growth. Since the level set function is used to provide implicitly\\u000a the location of the phase interface, it is resolved by an h-adaptive mesh with refinement only around the phase interface, while the thermal field is approximated on another h-adaptive mesh. The

  12. Aircraft Fault Detection and Classification Using Multi-Level Immune Learning Detection

    NASA Technical Reports Server (NTRS)

    Wong, Derek; Poll, Scott; KrishnaKumar, Kalmanje

    2005-01-01

    This work is an extension of a recently developed software tool called MILD (Multi-level Immune Learning Detection), which implements a negative selection algorithm for anomaly and fault detection that is inspired by the human immune system. The immunity-based approach can detect a broad spectrum of known and unforeseen faults. We extend MILD by applying a neural network classifier to identify the pattern of fault detectors that are activated during fault detection. Consequently, MILD now performs fault detection and identification of the system under investigation. This paper describes the application of MILD to detect and classify faults of a generic transport aircraft augmented with an intelligent flight controller. The intelligent control architecture is designed to accommodate faults without the need to explicitly identify them. Adding knowledge about the existence and type of a fault will improve the handling qualities of a degraded aircraft and impact tactical and strategic maneuvering decisions. In addition, providing fault information to the pilot is important for maintaining situational awareness so that he can avoid performing an action that might lead to unexpected behavior - e.g., an action that exceeds the remaining control authority of the damaged aircraft. We discuss the detection and classification results of simulated failures of the aircraft's control system and show that MILD is effective at determining the problem with low false alarm and misclassification rates.

  13. Massive fungal biodiversity data re-annotation with multi-level clustering.

    PubMed

    Vu, Duong; Szöke, Szániszló; Wiwie, Christian; Baumbach, Jan; Cardinali, Gianluigi; Röttger, Richard; Robert, Vincent

    2014-01-01

    With the availability of newer and cheaper sequencing methods, genomic data are being generated at an increasingly fast pace. In spite of the high degree of complexity of currently available search routines, the massive number of sequences available virtually prohibits quick and correct identification of large groups of sequences sharing common traits. Hence, there is a need for clustering tools for automatic knowledge extraction enabling the curation of large-scale databases. Current sophisticated approaches on sequence clustering are based on pairwise similarity matrices. This is impractical for databases of hundreds of thousands of sequences as such a similarity matrix alone would exceed the available memory. In this paper, a new approach called MultiLevel Clustering (MLC) is proposed which avoids a majority of sequence comparisons, and therefore, significantly reduces the total runtime for clustering. An implementation of the algorithm allowed clustering of all 344,239 ITS (Internal Transcribed Spacer) fungal sequences from GenBank utilizing only a normal desktop computer within 22 CPU-hours whereas the greedy clustering method took up to 242 CPU-hours. PMID:25355642

  14. Semantic segmentation based on multi-stage region-level clustering

    NASA Astrophysics Data System (ADS)

    Liu, Guoying; Zhou, Hongyu

    2013-10-01

    In the field of remote-sensed image segmentation, it is very important to obtain semantic results. However, in high resolution remote sensed images, different complex patterns always have components with the same spectrum, which makes it rather difficult to extract such patterns only through traditional clustering methods. In this paper, a novel multi-stage region-level clustering method is proposed to solve this problem. Firstly, the initial oversegmentation is obtained by using the Mean Shift algorithm, based on which a region adjacent graph (RAG) is built; Then, FCM is employed to get the spectral-based segmentation result; After that, the context clues for each region is calculated according to the label and size of neighboring regions, followed by the second FCM clustering on each set of regions with the same label to distinct regions with the same spectrum but belongs to different objects; Rearranging all of these clustering results to form the finial processing unit, this algorithm goes a step further to calculate more accurate context clues, and use the third FCM to obtain the final segmentation result. Experiments on the high resolution remote-sensed images have shown the superiority to the competitions.

  15. Hexagram Inverter for Medium-Voltage Six-Phase Variable-Speed Drives

    Microsoft Academic Search

    Jun Wen; Keyue Ma Smedley

    2008-01-01

    A new multilevel inverter - hexagram inverter is proposed for medium-voltage (MV) variable-speed-drive (VSD) applications, which is composed of six standard two-level voltage source inverter (VSI) modules interconnected through the inductors. With six AC terminals, it can be used for both three- and six-phase drives. This paper studies its six-phase applications. Compared to a same output power and voltage VSI,

  16. Modeling flow through the sand pack: implications for groundwater sampling from multi- level monitoring wells in fractured bedrock aquifers.

    NASA Astrophysics Data System (ADS)

    Kozuskanich, J.; Novakowski, K.; Anderson, B.

    2009-05-01

    Multi-level piezometers are often used in groundwater studies to monitor multiple zones within a single borehole. In the fractured rock setting the monitoring intervals are typically designed to isolate discrete fracture features (single fractures or fracture zones). This can be very useful for determining vertical connectivity and the distribution of a contaminant within a fractured rock aquifer. A simple and inexpensive method for completing a bedrock borehole as a multi-level piezometer is to use PVC screen and riser, a sand pack around the screened section, and bentonite to isolate each interval. Flow into the borehole is dominantly confined to the intersecting discrete fracture features. The objective of this study is to examine the nature of the flow through the sand pack and screen slots as water travels from the fracture to the pump intake under pumping conditions. Our conceptual model suggests only a portion of the sand pack in the vicinity of the fractures should be hydraulically active in this scenario. Thus, portions of the wellbore may remain stagnant during pumping depending on the location of the pump intake with respect to the fractures. Flow paths in the sand pack may be controlled by the relationship between the transmissivity of the fracture and screen slots. HydroGeoSphere, a numerical model for flow and solute transport in discrete fractures and porous media, will be used to validate the conceptual model and define the head and velocity profiles in a multi-level interval under various pumping rate and discrete fracture aperture scenarios. The results of this study could have implications for defining a "well volume" in sampling protocols designed for multi-level piezometers in bedrock aquifer systems. The results may also be a useful tool for interpreting the significance of the sand pack as a source of bacteria in water quality monitoring studies that use multi-level piezometer construction of this sort.

  17. Planar wire array performance scaling at multi-MA levels on the Saturn generator.

    SciTech Connect

    Chuvatin, Alexander S. (Laboratoire du Centre National de la Recherche Scientifique Ecole Polytechnique, Palaiseau, France); Jones, Michael; Vesey, Roger Alan; Waisman, Eduardo M.; Esaulov, Andrey A. (University of Nevada, Reno, NV); Ampleford, David J.; Kantsyrev, Victor Leonidovich (University of Nevada, Reno, NV); Cuneo, Michael Edward; Rudakov, L. I. (Icarus Research Inc., Bethesda, MD); Coverdale, Christine Anne; Jones, Brent Manley; Safronova, Alla S. (University of Nevada, Reno, NV)

    2007-10-01

    A series of twelve shots were performed on the Saturn generator in order to conduct an initial evaluation of the planar wire array z-pinch concept at multi-MA current levels. Planar wire arrays, in which all wires lie in a single plane, could offer advantages over standard cylindrical wire arrays for driving hohlraums for inertial confinement fusion studies as the surface area of the electrodes in the load region (which serve as hohlraum walls) may be substantially reduced. In these experiments, mass and array width scans were performed using tungsten wires. A maximum total radiated x-ray power of 10 {+-} 2 TW was observed with 20 mm wide arrays imploding in {approx}100 ns at a load current of {approx}3 MA, limited by the high inductance. Decreased power in the 4-6 TW range was observed at the smallest width studied (8 mm). 10 kJ of Al K-shell x-rays were obtained in one Al planar array fielded. This report will discuss the zero-dimensional calculations used to design the loads, the results of the experiments, and potential future research to determine if planar wire arrays will continue to scale favorably at current levels typical of the Z machine. Implosion dynamics will be discussed, including x-ray self-emission imaging used to infer the velocity of the implosion front and the potential role of trailing mass. Resistive heating has been previously cited as the cause for enhanced yields observed in excess of jxB-coupled energy. The analysis presented in this report suggests that jxB-coupled energy may explain as much as the energy in the first x-ray pulse but not the total yield, which is similar to our present understanding of cylindrical wire array behavior.

  18. PWR integrated safety analysis methodology using multi-level coupling algorithm

    NASA Astrophysics Data System (ADS)

    Ziabletsev, Dmitri Nickolaevich

    Coupled three-dimensional (3D) neutronics/thermal-hydraulic (T-H) system codes give a unique opportunity for a realistic modeling of the plant transients and design basis accidents (DBA) occurring in light water reactors (LWR). Examples of such DBAs are the rod ejection accidents (REA) and the main steam line break (MSLB) that constitute the bounding safety problems for pressurized water reactors (PWR). These accidents involve asymmetric 3D spatial neutronic and T-H effects during the course of the transients. The thermal margins (the peak fuel temperature, and departure from nucleate boiling ratio (DNBR)) are the measures of safety at a particular transient and need to be evaluated as accurate as possible. Modern 3D neutronics/T-H coupled codes estimate the safety margins coarsely on an assembly level, i.e. for an average fuel pin. More accurate prediction of the safety margins requires the evaluation of the transient fuel rod response involving locally coupled neutronics/T-H calculations. The proposed approach is to perform an on-line hot-channel safety analysis not for the whole core but for a selected local region, for example for the highest power loaded fuel assembly. This approach becomes feasible if an on-line algorithm capable to extract the necessary input data for a sub-channel module is available. The necessary input data include the detailed pin-power distributions and the T-H boundary conditions for each sub-channel in the considered problem. Therefore, two potential challenges are faced in the development of refined methodology for evaluation of local safety parameters. One is the development of an efficient transient pin-power reconstruction algorithm with a consistent cross-section modeling. The second is the development of a multi-level coupling algorithm for the T-H boundary and feed-back data exchange between the sub-channel module and the main 3D neutron kinetics/T-H system code, which already uses one level of coupling scheme between 3D neutronics and core thermal-hydraulics models. The major accomplishment of the thesis is the development of an integrated PWR safety analysis methodology with locally refined safety evaluations. This involved introduction of an improved method capable of efficiently restoring the fine pin-power distribution with a high degree of accuracy. In order to apply the methodology to evaluate the safety margins on a pin level, a refined on-line hot channel model was developed accounting for the cross-flow effects. Finally, this methodology was applied to best estimate safety analysis to more accurately calculate the thermal safety margins occurring during a design basis accident in PWR.

  19. Optimized space vector switching sequences for multilevel inverters

    Microsoft Academic Search

    Brendan Peter McGrath; Donald Grahame Holmes; Thomas Lipo

    2003-01-01

    Previous work has shown that space vector modulation and carrier modulation for two-level inverters achieve the same phase leg switching sequences when appropriate zero sequence offsets are added to the reference waveforms for carrier modulation. This paper presents a similar equivalence between the phase disposition (PD) carrier and space vector modulation strategies applied to diode clamped, cascaded N-level or hybrid

  20. The tandem inverter: combining the advantages of voltage-source and current-source inverters

    Microsoft Academic Search

    A. M. Trznadlowski; F. Blaabjerg; J. K. Pedersen; N. Patriciu

    1998-01-01

    A combination of a current-source primary inverter and a voltage-source secondary inverter is proposed as the so-called tandem inverter. The primary inverter operates in the square-wave mode, handling most of the converted power, while its output harmonic currents are compensated by the much smaller secondary inverter. As a result, the tandem inverter, to be used for AC motor control, combines

  1. A multi-level perspective on small-area health and mortality: a case study of England and Wales.

    PubMed

    Congdon, P; Shouls, S; Curtis, S

    1997-09-01

    "This paper considers morbidity and mortality variations at the small-area level in England and Wales and their relation to socio-economic factors. Separate affluence and deprivation effects on illness and mortality are identified from a single-level analysis, both exceeding the influence of social class, urbanity or ethnicity. A multi-level perspective is then adopted to explore ecological associations operating both at micro-area and higher level spatial scales. Contextual effects (higher level variability in the impacts of ward level variables) are identified in the effects of small area deprivation on mortality and illness, as well as cross-level interactions; thus the impact of small area social structure on health is partly defined by the wider regional and district setting." PMID:12348291

  2. 1412 IEEE TRANSACTIONS ON VERY LARGE SCALE INTEGRATION (VLSI) SYSTEMS, VOL. 18, NO. 10, OCTOBER 2010 Improving Multi-Level NAND Flash Memory

    E-print Network

    Zhang, Tong

    design practice that uses BCH codes only. The key is that TCM can well leverage the multi-level storage dominating global flash memory market. In current design practice, most MLC NAND flash memories store 2 bits 2010 Improving Multi-Level NAND Flash Memory Storage Reliability Using Concatenated BCH-TCM Coding Shu

  3. 49 CFR Figure 2 to Subpart B of... - Example of a Multi-Level Car Complying with Window Location and Staggering Requirements-§§ 238...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...2011-10-01 false Example of a Multi-Level Car Complying with Window Location and Staggering Requirements-§§ 238.113 and...of Part 238—Example of a Multi-Level Car Complying with Window Location and Staggering Requirements—§§ 238.113 and...

  4. 49 CFR Figure 2 to Subpart B of... - Example of a Multi-Level Car Complying with Window Location and Staggering Requirements-§§ 238...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...2012-10-01 false Example of a Multi-Level Car Complying with Window Location and Staggering Requirements-§§ 238.113 and...of Part 238—Example of a Multi-Level Car Complying with Window Location and Staggering Requirements—§§ 238.113 and...

  5. 49 CFR Figure 2 to Subpart B of... - Example of a Multi-Level Car Complying with Window Location and Staggering Requirements-§§ 238...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 false Example of a Multi-Level Car Complying with Window Location and Staggering Requirements-§§ 238.113 and...of Part 238—Example of a Multi-Level Car Complying with Window Location and Staggering Requirements—§§ 238.113 and...

  6. 49 CFR Figure 2 to Subpart B of... - Example of a Multi-Level Car Complying with Window Location and Staggering Requirements-§§ 238...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 false Example of a Multi-Level Car Complying with Window Location and Staggering Requirements-§§ 238.113 and...of Part 238—Example of a Multi-Level Car Complying with Window Location and Staggering Requirements—§§ 238.113 and...

  7. 49 CFR Figure 2 to Subpart B of... - Example of a Multi-Level Car Complying with Window Location and Staggering Requirements-§§ 238...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 false Example of a Multi-Level Car Complying with Window Location and Staggering Requirements-§§ 238.113 and...of Part 238—Example of a Multi-Level Car Complying with Window Location and Staggering Requirements—§§ 238.113 and...

  8. Groundwater Age in Multi-Level Water Quality Monitor Wells on California Central Valley Dairies

    NASA Astrophysics Data System (ADS)

    Esser, B. K.; Visser, A.; Hillegonds, D. J.; Singleton, M. J.; Moran, J. E.; Harter, T.

    2011-12-01

    Dairy farming in California's Central Valley is a significant source of nitrate to underlying aquifers. One approach to mitigation is to implement farm-scale management plans that reduce nutrient loading to groundwater while sustaining crop yield. While the effect of different management practices on crop yield is easily measured, their effect on groundwater quality has only infrequently been evaluated. Documenting and predicting the impact of management on water quality requires a quantitative assessment of transport (including timescale and mixing) through the vadose and saturated zones. In this study, we measured tritium, helium isotopic composition, and noble gas concentrations in groundwater drawn from monitor wells on several dairies in the Lower San Joaquin Valley and Tulare Lake Basin of California's Central Valley in order to predict the timescales on which changes in management may produce observable changes in groundwater quality. These dairies differ in age (from <10 to >100 years old), thickness of the vadose zone (from <10 to 60 m), hydrogeologic setting, and primary source of irrigation water (surface or groundwater). All of the dairies use manure wastewater for irrigation and fertilization. Three of the dairies have implemented management changes designed to reduce nutrient loading and/or water usage. Monitor wells in the southern Tulare Lake Basin dairies were installed by UC-Davis as multi-level nested wells allowing depth profiling of tritium and noble gases at these sites. Tritium/helium-3 groundwater ages, calculated using a simple piston-flow model, range from <2 to >50 years. Initial tritium (the sum of measured tritium and tritiogenic helium-3) is close to or slightly above precipitation in the calculated recharge year for young samples; and significantly above the precipitation curve for older samples. This pattern is consistent with the use of 20-30 year old groundwater recharged before 1980 for irrigation, and illustrates how irrigation with groundwater can complicate the use of tritium alone for age dating. The presence of radiogenic helium-4 in several samples with measurable tritium provides evidence of mixing between pre-modern and younger groundwater. Groundwater age-depth relationships are complicated, consistent with transient flow patterns in shallow agricultural groundwaters affected by irrigation pumping and recharge. For the multi-level installations in the southern dairies, both depth profiles and re-sampling after significant changes in groundwater elevation emphasize the need to sample groundwater within 3 meters of the water table to obtain "first-encounter" groundwater with a tritium/helium-3 age of less than 5 years, and to use age tracers to identify wells and groundwater conditions suitable for monitoring and assessment of best management practice impacts on underlying groundwater quality. This work was carried out with funding from Sustainable Conservation and the California State Water Resources Control Board in collaboration with UC-Davis, and was performed under the auspices of the U.S. DOE by LLNL under Contract DE-AC52-07NA27344.

  9. An Efficient Approach to Multi-level Route Ang Chen, Edmond W. W. Chan, Xiapu Luo, Waiting W. T. Fok, and Rocky K. C. Chang

    E-print Network

    Plotkin, Joshua B.

    's Ark Lab The Hong Kong Polytechnic University Huawei Technologies, China {csachen|csxluo|cswtfok|csrchang}@comp.polyu.edu.hk edmond.chan@huawei.com Abstract--Contrasting multi-level routes (e.g., IP, subnet, AS levels

  10. A dedicated database system for handling multi-level data in systems biology

    PubMed Central

    2014-01-01

    Background Advances in high-throughput technologies have enabled extensive generation of multi-level omics data. These data are crucial for systems biology research, though they are complex, heterogeneous, highly dynamic, incomplete and distributed among public databases. This leads to difficulties in data accessibility and often results in errors when data are merged and integrated from varied resources. Therefore, integration and management of systems biological data remain very challenging. Methods To overcome this, we designed and developed a dedicated database system that can serve and solve the vital issues in data management and hereby facilitate data integration, modeling and analysis in systems biology within a sole database. In addition, a yeast data repository was implemented as an integrated database environment which is operated by the database system. Two applications were implemented to demonstrate extensibility and utilization of the system. Both illustrate how the user can access the database via the web query function and implemented scripts. These scripts are specific for two sample cases: 1) Detecting the pheromone pathway in protein interaction networks; and 2) Finding metabolic reactions regulated by Snf1 kinase. Results and conclusion In this study we present the design of database system which offers an extensible environment to efficiently capture the majority of biological entities and relations encountered in systems biology. Critical functions and control processes were designed and implemented to ensure consistent, efficient, secure and reliable transactions. The two sample cases on the yeast integrated data clearly demonstrate the value of a sole database environment for systems biology research. PMID:25053973

  11. Multi-scale dynamical analysis (MSDA) of sea level records versus PDO, AMO, and NAO indexes

    NASA Astrophysics Data System (ADS)

    Scafetta, N.

    2013-04-01

    Herein I propose a multi-scale dynamical analysis to facilitate the physical interpretation of tide gauge records. The technique uses graphical diagrams. It is applied to six secular-long tide gauge records representative of the world oceans: Sydney, Pacific coast of Australia; Fremantle, Indian Ocean coast of Australia; New York City, Atlantic coast of USA; Honolulu, US state of Hawaii; San Diego, US state of California; and Venice, Mediterranean Sea, Italy. For comparison, an equivalent analysis is applied to the Pacific Decadal Oscillation (PDO) index and to the Atlantic Multidecadal Oscillation (AMO) index. Finally, a global reconstruction of sea level (Jevrejeva et al. in Geophys Res Lett 35:L08715, 2008) and a reconstruction of the North Atlantic Oscillation (NAO) index (Luterbacher et al. in Geophys Res Lett 26:2745-2748, 1999) are analyzed and compared: both sequences cover about three centuries from 1700 to 2000. The proposed methodology quickly highlights oscillations and teleconnections among the records at the decadal and multidecadal scales. At the secular time scales tide gauge records present relatively small (positive or negative) accelerations, as found in other studies (Houston and Dean in J Coast Res 27:409-417, 2011). On the contrary, from the decadal to the secular scales (up to 110-year intervals) the tide gauge accelerations oscillate significantly from positive to negative values mostly following the PDO, AMO and NAO oscillations. In particular, the influence of a large quasi 60-70 year natural oscillation is clearly demonstrated in these records. The multiscale dynamical evolutions of the rate and of the amplitude of the annual seasonal cycle of the chosen six tide gauge records are also studied.

  12. MLCCA Multi-Level Composability Check Architecture for Dependable Communication over Heterogeneous Networks

    E-print Network

    systems, it is cruical to ensure the composability of the de- ployed applications and network protocols- liness or dependability. To take an example from the automotive area, FlexRay [4], TTCAN [5] or multi

  13. A distributed TS-MUX architecture for multi-chip extension beyond the HDTV level

    Microsoft Academic Search

    Takayuki Onishi; Mitsuo Ikeda; Jiro Naganuma; Makoto Endo; Yoshiyuki Yashima

    2004-01-01

    This paper proposes a distributed stream multiplexing architecture for CODEC LSIs with multi-chip configuration, and demonstrates its scalability and usefulness. It consists of each media multiplexing unit with an external stream input and inter-chip communication interfaces. Parallel protocol processing, with an autonomous inter-chip control mechanism to mix and concatenate packets through daisy-chained transfer paths, provides a complete multi-chip output at

  14. Inverter design for high frequency power distribution

    NASA Technical Reports Server (NTRS)

    King, R. J.

    1985-01-01

    A class of simple resonantly commutated inverters are investigated for use in a high power (100 KW - 1000 KW) high frequency (10 KHz - 20 KHz) AC power distribution system. The Mapham inverter is found to provide a unique combination of large thyristor turn-off angle and good utilization factor, much better than an alternate 'current-fed' inverter. The effects of loading the Mapham inverter entirely with rectifier loads are investigated by simulation and with an experimental 3 KW 20 KHz inverter. This inverter is found to be well suited to a power system with heavy rectifier loading.

  15. Association between multi-level inorganic arsenic exposure from drinking water and skin lesions in China.

    PubMed

    Guo, Xiaojuan; Fujino, Yoshihisa; Ye, Xiaolei; Liu, Jun; Yoshimura, Takesumi

    2006-09-01

    Arsenic is one of the most important toxicants in the environment. In Inner Mongolia of China, 300,000 residents are believed to be drinking water containing >50 microg/liter. Skin lesions have been known as the most common consequences resulting from chronic exposure to arsenic. To clarify the prevalence of arsenic-induced skin lesions, it is important to assess the impact of this problem among the target population, and to make future planning. We evaluated the association between multi-levels inorganic arsenic exposure from drinking water and skin lesions in an arsenic-affected area in Inner Mongolia, China. One hundred nine and 32 subjects in high (>50 microg/liter) and low (<50 microg/liter) arsenic-affected villages were recruited and had the detailed physical examination with special emphasis on arsenic-related skin lesions. Arsenic exposure was measured for each participant with respect to iAs concentration of primary well and the duration using the well. Arsenic-induced skin lesions including keratosis, pigmentation, and/or depigmentation were diagnosed in 56 and 3 subjects in the two villages, respectively. Logistic regression was conducted to calculate odd ratios of skin lesions associated with arsenic exposure with adjustments for sex, age group, smoking and duration of exposure. A consistent dose-response relationship between arsenic exposure level and skin lesion risk was observed. Compared to those with iAs concentration <50 microg/liter, the adjusted odds ratios of skin lesions for the subjects with 51-99, 100-149 and >150 microg/liter were 33.3% (OR =15.50, 95% CI: 1.53-248.70), 46.7% (OR =16.10, 95% CI: 3.73-69.63) and 55.7% (OR= 25.70, 95% CI: 6.43-102.87), respectively. Duration of using well was not associated with increased risk of skin lesions in this population; (OR =1.68, 95% CI: 0.40-6.91 for 6-15 years, OR = 2.30, 95% CI: 0.58-9.14 for over 15 years) compared with the duration of less than 5 years. PMID:16968972

  16. Socioeconomic Status and the Health of Youth: A Multi-level, Multi-domain Approach to Conceptualizing Pathways

    PubMed Central

    Schreier, Hannah M. C.; Chen, Edith

    2012-01-01

    Previous research has clearly established associations between low socioeconomic status (SES) and poor youth physical health outcomes. This article provides an overview of the main pathways through which low SES environments come to influence youth health. We focus on two of the most prevalent chronic health problems in youth today, asthma and obesity. We review and propose a model that encompasses (1) multiple levels of influence, including the neighborhood, family and person level, (2) both social and physical domains in the environment, and finally (3) dynamic relationships between these factors. A synthesis of existing research and our proposed model draw attention to the notion of adverse physical and social exposures in youth’s neighborhood environments altering family characteristics and youth psychosocial and behavioral profiles, thereby increasing youth’s risk for health problems. We also note the importance of acknowledging reciprocal influences across levels and domains (e.g., between family and child) that create self-perpetuating patterns of influence that further accentuate the impact of these factors on youth health. Finally, we document that factors across levels can interact (e.g., environmental pollution levels with child stress) to create unique, synergistic effects on youth health. Our model stresses the importance of evaluating influences on youth’s physical health not in isolation but in the context of the broader social and physical environments in which youth live. Understanding the complex relationships between the factors that link low SES to youth’s long-term health trajectories is necessary for the creation and implementation of successful interventions and policies to ultimately reduce health disparities. PMID:22845752

  17. Improved partial response maximum likelihood method combining modulation code for signal waveform modulation multi-level disc

    NASA Astrophysics Data System (ADS)

    Wang, He-Qun; Pei, Jing; Pan, Long-Fa

    2014-10-01

    In this paper, we describe an improved adaptive partial response maximum likelihood (PRML) method combining modulation code for signal waveform modulation multi-level disc. This improved adaptive PRML method employs partial response equalizer and adaptive viterbi detector combining modulation code. Compared with the traditional adaptive PRML detector, the improved PRML detector additionally employs illogical sequence detector and corrector. Illogical sequence detector and corrector can avoid the appearance of illogical sequences effectively, which do not follow the law of modulation code for signal waveform modulation multi-level disc, and obtain the correct sequences. We implement the improved PRML detector using a DSP and an FPGA chip. The experimental results show good performance. The higher efficient and lower complexity can be obtained by using the improved PRML method than by using the previous PRML method. Meanwhile, resource utilization of the improved PRML detector is not changed, but the bit error rate (BER) is reduced by more than 20%.

  18. Static shunt and series compensations of an SMIB system using flying capacitor multilevel inverter

    Microsoft Academic Search

    Anshuman Shukla; Arindam Ghosh; Avinash Joshi

    2005-01-01

    The flying capacitor multilevel inverter (FCMLI) is a multiple voltage level inverter topology intended for high-power and high-voltage operations at low distortion. It uses capacitors, called flying capacitors, to clamp the voltage across the power semiconductor devices. A method for controlling the FCMLI is proposed which ensures that the flying capacitor voltages remain nearly constant using the preferential charging and

  19. A LOGICAL INVERTED TAXONOMY OF SORTING ALGORITHMS S.M. Merritt K.K. Lau

    E-print Network

    Lau, Kung-Kiu

    A LOGICAL INVERTED TAXONOMY OF SORTING ALGORITHMS S.M. Merritt K.K. Lau School of Computer Science taxonomy of sorting algorithms, a high­level, top­down, conceptually simple and symmetric categorization taxonomy of sorting algorithms. This provides a logical basis for the inverted taxonomy and expands

  20. Abstract--A reconfiguration technique for multilevel inverters incorporating a diagnostic system based on neural

    E-print Network

    Tolbert, Leon M.

    it uses several level dc voltage sources which would be available from batteries or fuel cells [1 will disconnect the power sources from the multilevel inverter system whenever a fault occurs, stopping source inverter (VSI) system. The various fault modes for an induction motor are investigated in [3

  1. Evaluation of a high power ARCP voltage source inverter with IGCTs

    Microsoft Academic Search

    S. Bernet; R. Teichmann; J. Weber; P. K. Steimer

    1999-01-01

    An evaluation and comparison of a two-level conventional voltage source inverter (VSI) and an auxiliary resonant commutated pole voltage source inverter (ARCPVSI) featuring IGCTs for a 3 MVA application is presented. Design issues of both topologies are addressed. The IGCT loss approximations are based on extensive measurements of the devices under hard and soft switching conditions. The results show that

  2. A new multi-unit iris authentication based on quality assessment and score level fusion for mobile phones

    Microsoft Academic Search

    Byung Jun Kang; Kang Ryoung Park

    2010-01-01

    Although iris recognition technology has been reported to be more stable and reliable than other biometric systems, performance\\u000a can be degraded due to many factors such as small eyes, camera defocusing, eyelash occlusions and specular reflections on\\u000a the surface of glasses. In this paper, we propose a new multi-unit iris authentication method that uses score level fusion\\u000a based on a

  3. Feature-Level Fusion by Multi-Objective Binary Particle Swarm Based Unbiased Feature Selection for Optimized Sensor System Design

    Microsoft Academic Search

    Kuncup Iswandy; Andreas Koenig

    2006-01-01

    The performance of recognition systems in intelligent sensor technology can often be improved by using the combined information of several different measurement results, i.e., signal processing and feature computation, of single-sensor and\\/or multi-sensor information. However, the large dimensional data caused by feature-level fusion imposes an accuracy problem on classification tasks, due to some irrelevant and\\/or redundant features. For this reason,

  4. On the use of a hierarchical multi-level building block basis function scheme in periodic plasmonic structures

    NASA Astrophysics Data System (ADS)

    Zheng, X.; Valev, V. K.; Volskiy, V.; Vandenbosch, Guy A. E.; Moshchalkov, V. V.

    2014-05-01

    A Volumetric Method of Moments algorithm is applied to predict the plasmonic responses of chiral metamaterials. This algorithm is based on the use of a multi-level building block basis function scheme, in combination with a dedicated Kummer transformation in the calculation of periodic Green's functions. The validity of the algorithm is demonstrated by analyzing a Ninja Star periodic structure. A good agreement can be found between simulation and experiment.

  5. Advanced Modular Inverter Technology Development

    SciTech Connect

    Adam Szczepanek

    2006-02-04

    Electric and hybrid-electric vehicle systems require an inverter to convert the direct current (DC) output of the energy generation/storage system (engine, fuel cells, or batteries) to the alternating current (AC) that vehicle propulsion motors use. Vehicle support systems, such as lights and air conditioning, also use the inverter AC output. Distributed energy systems require an inverter to provide the high quality AC output that energy system customers demand. Today's inverters are expensive due to the cost of the power electronics components, and system designers must also tailor the inverter for individual applications. Thus, the benefits of mass production are not available, resulting in high initial procurement costs as well as high inverter maintenance and repair costs. Electricore, Inc. (www.electricore.org) a public good 501 (c) (3) not-for-profit advanced technology development consortium assembled a highly qualified team consisting of AeroVironment Inc. (www.aerovironment.com) and Delphi Automotive Systems LLC (Delphi), (www.delphi.com), as equal tiered technical leads, to develop an advanced, modular construction, inverter packaging technology that will offer a 30% cost reduction over conventional designs adding to the development of energy conversion technologies for crosscutting applications in the building, industry, transportation, and utility sectors. The proposed inverter allows for a reduction of weight and size of power electronics in the above-mentioned sectors and is scalable over the range of 15 to 500kW. The main objective of this program was to optimize existing AeroVironment inverter technology to improve power density, reliability and producibility as well as develop new topology to reduce line filter size. The newly developed inverter design will be used in automotive and distribution generation applications. In the first part of this program the high-density power stages were redesigned, optimized and fabricated. One of the main tasks was to design and validate new gate drive circuits to provide the capability of high temp operation. The new power stages and controls were later validated through extensive performance, durability and environmental tests. To further validate the design, two power stages and controls were integrated into a grid-tied load bank test fixture, a real application for field-testing. This fixture was designed to test motor drives with PWM output up to 50kW. In the second part of this program the new control topology based on sub-phases control and interphase transformer technology was successfully developed and validated. The main advantage of this technology is to reduce magnetic mass, loss and current ripple. This report summarizes the results of the advanced modular inverter technology development and details: (1) Power stage development and fabrication (2) Power stage validation testing (3) Grid-tied test fixture fabrication and initial testing (4) Interphase transformer technology development

  6. Enabling the MLSpOC (Multi-Level Space Operations Center) of the Future

    NASA Astrophysics Data System (ADS)

    Missal, D.

    2012-09-01

    The Intelligence Reform and Terrorism Prevention Act, passed by Congress in 2004, established the expectation that the "vast intelligence enterprise" of the United States would become more unified, coordinated, and effective. This law charged the intelligence community and government agencies to integrate foreign intelligence and domestic US intelligence components to reduce gaps in understanding threats to our national security and to improve our reaction. This intelligence strategy — designed to provide more comprehensive and accurate intelligence analysis—substantially increases requirements for secure data sharing capabilities. An information system must be Certified & Accredited (C&A) by the appropriate Accreditation Authority in accordance with each Authority's prescribed compliance requirements and governance. Cross-Domain Solutions (CDSs) can provide the ability to share data between multiple operating domains (e.g. among users on Top Secret and Secret networks). However, sharing sensitive data across security domains and networks has been impeded by both technical and cultural challenges. A viable CDS requires a tremendous investment for initial C&A and many solutions are limited with respect to the integration of an organization's applications. As a result, most of today's highly secured systems have been designed to restrict access to entire user populations rather than implement data sharing on the basis of mandatory access controls and an individual's need-to-know. Most CDSs today are based on one-way replication through data transfer guards that copy data from one network to another. This model inherently builds in additional and extensive Operations and Maintenance (O&M) costs. Oracle's National Security Group challenged its top engineers and security architects to engineer the first Cross-Domain database providing a practical and robust solution to the Cross-Domain security problem. The result is the MLSpOC, which is deployed, fielded, and accredited today at multiple sites both CONUS and OCONUS. It is designed to assist information systems developers achieve DCID 6/3 Protection Level 4 or 5 (PL4 or PL5) or DoD SABI C&A for SECRET-to-UNCLASSIFIED systems (PL3). The product is on the DoD/DNI Unified Cross-domain Management Office's (UCDMO) Baseline of accredited solutions, and is the only solution on the Baseline which the Government considers to be an "All-in-One" approach to the Cross-domain Security challenge. Our solution is also the only PL-4 Cloud in existence and that is deployed and operational in the entire world today (at DIA). The Space marketplace is a very unique cross-domain challenge, as a need exists for Unclassified SSA Data Sharing at a deeper and more fundamental level than anywhere else in the IC or DoD. For instance, certain Agencies and/or Programs have a requirement to share information with Partner Nations that are not considered to be "friendly" (e.g. China). Our Solution is the ONLY solution in the world today that's achieved C&A, and that is uniquely positioned to enable the Multi-level Space Operations Center (MLSpOC) of the Future.

  7. Quality of Research Design Moderates Effects of Grade Retention on Achievement: A Meta-analytic, Multi-level Analysis

    PubMed Central

    Allen, Chiharu S.; Chen, Qi; Willson, Victor L.; Hughes, Jan N.

    2010-01-01

    The present meta-analysis examined the effect of grade retention on academic outcomes and investigated systemic sources of variability in effect sizes. Using multi-level modeling, we investigated characteristics of 207 effect sizes across 22 studies published between 1990 and 2007 at two levels: the study (between) and individual (within) levels. Design quality was a study-level variable. Individual level variables were median grade retained and median number of years post retention. Quality of design was associated with less negative effects. Studies employing middle to high methodological designs yielded effect sizes not statistically significantly different from zero and 0.34 higher (more positive) than studies with low design quality. Years post retention was negatively associated with retention effects, and this effect was stronger for studies using grade comparisons versus age comparisons. Results challenge the widely held view that retention has a negative impact on achievement. Suggestions for future research are discussed. PMID:20717492

  8. OptCom: A Multi-Level Optimization Framework for the Metabolic Modeling and Analysis of Microbial Communities

    PubMed Central

    Zomorrodi, Ali R.; Maranas, Costas D.

    2012-01-01

    Microorganisms rarely live isolated in their natural environments but rather function in consolidated and socializing communities. Despite the growing availability of high-throughput sequencing and metagenomic data, we still know very little about the metabolic contributions of individual microbial players within an ecological niche and the extent and directionality of interactions among them. This calls for development of efficient modeling frameworks to shed light on less understood aspects of metabolism in microbial communities. Here, we introduce OptCom, a comprehensive flux balance analysis framework for microbial communities, which relies on a multi-level and multi-objective optimization formulation to properly describe trade-offs between individual vs. community level fitness criteria. In contrast to earlier approaches that rely on a single objective function, here, we consider species-level fitness criteria for the inner problems while relying on community-level objective maximization for the outer problem. OptCom is general enough to capture any type of interactions (positive, negative or combinations thereof) and is capable of accommodating any number of microbial species (or guilds) involved. We applied OptCom to quantify the syntrophic association in a well-characterized two-species microbial system, assess the level of sub-optimal growth in phototrophic microbial mats, and elucidate the extent and direction of inter-species metabolite and electron transfer in a model microbial community. We also used OptCom to examine addition of a new member to an existing community. Our study demonstrates the importance of trade-offs between species- and community-level fitness driving forces and lays the foundation for metabolic-driven analysis of various types of interactions in multi-species microbial systems using genome-scale metabolic models. PMID:22319433

  9. Update on SIC-Based Inverter Technology

    SciTech Connect

    Chinthavali, Madhu Sudhan [ORNL; Zhang, Hui [ORNL; Tolbert, Leon M [ORNL; Ozpineci, Burak [ORNL

    2009-01-01

    This paper presents a study of silicon carbide (SiC) technology which includes device characterization and modeling, inverter simulation, and test results for several prototype inverters. The static and dynamic characteristics of discrete devices and half bridge modules are presented. Test results of a 55 kW hybrid inverter with SiC Schottky diodes and an 18 kW all-SiC inverter using SiC JFETs and Schottky diodes are demonstrated.

  10. Inverted repeats as genetic elements for promoting DNA inverted duplication: implications in gene amplification

    Microsoft Academic Search

    Ching-Tai Lin; Wei-Hsin Lin; Yi Lisa Lyu; Jacqueline Whang-Peng

    2001-01-01

    Inverted repeats are important genetic elements for genome instability. In the current study we have investigated the role of inverted repeats in a DNA rearrangement reaction using a linear DNA substrate. We show that linear DNA substrates with terminal inverted repeats can efficiently transform Escherichia coli. The transformation products contain circular inverted dimers in which the DNA sequences between terminal

  11. Leica-Inverted-2 -1-Short instructions Short instructions for the Leica-Inverted-2

    E-print Network

    Manstein, Dietmar J.

    Leica-Inverted-2 -1- Short instructions Short instructions for the Leica-Inverted-2 Version 230307 off the system Page 8 8. Trouble shooting Page 10 #12;Leica-Inverted-2 -2- Short instructions 1. Laser;Leica-Inverted-2 -3- Short instructions 2. General guidelines 1. Lab rules: This room is a S2 laboratory

  12. Leica-Inverted-MP -1-Short instructions Short instructions for the Leica-Inverted-MP

    E-print Network

    Manstein, Dietmar J.

    Leica-Inverted-MP -1- Short instructions Short instructions for the Leica-Inverted-MP Version Page 11 #12;Leica-Inverted-MP -2- Short instructions 1. Laser safety Safety notes for operating be completely switched off. 11. Do not remove the microscope condenser. #12;Leica-Inverted-MP -3- Short

  13. David J. Hathaway, IBM EDAInverter Minimization 1 Inverter Minimization -OverviewInverter Minimization -Overview

    E-print Network

    Ellis-Monaghan, Joanna

    David J. Hathaway, IBM EDAInverter Minimization 1 Inverter Minimization - OverviewInverter network a polarity graph 9 Initially consider only equal cost AND, NAND, OR, and NOR gates 9 Inverters for covering fundamental cycles 9 Considering electrically useful inverters #12;David J. Hathaway, IBM

  14. Development and applications of a multi-level strain energy method for detecting finite element modeling errors

    NASA Technical Reports Server (NTRS)

    Hashemi-Kia, Mostafa; Kilroy, Kevin L.; Parker, G.

    1990-01-01

    A computational procedure is described which can be used efficiently in identifying modeling errors which may arise from development of a structural finite element model. The procedure, which is referred to as the multi-level strain energy check, is set up in the form of a set of NASTRAN DMAP alters which provide sufficient information about the modeling errors at G-Set, N-Set, and F-Set levels. This technique was applied to two NASTRAN models, namely, the AH-64A and AH-1G models. Two modeling errors were identified for the AH-1G, which were then corrected.

  15. Inverting input scanner vibration errors

    Microsoft Academic Search

    George Wolberg; Robert C. Loce

    1995-01-01

    Images scanned in the presence of mechanical vibrations are subject to artifacts such as brightness fluctuation and geometric warping. The goal of this work is to develop an algorithm to invert these distortions and produce an output digital image consistent with a scanner operating under ideal uniform motion conditions. The image restoration algorithm described in this paper applies to typical

  16. Analytical transient response of CMOS inverters

    Microsoft Academic Search

    A. I. Kayssi; K. A. Sakallah; T. M. Burks

    1992-01-01

    A general formula relating the waveform at the output of a CMOS inverter to the waveform at its input is derived. The formula is applied to three cases: a step input, a ramp input, and an exponential input. A one-dimensional function dependence of the inverter propagation delay and output slew rate on circuit parameters is derived and an inverter macromodel

  17. Joint Inverted Indexing Kaiming He2

    E-print Network

    Bernstein, Phil

    Joint Inverted Indexing Yan Xia1 Kaiming He2 Fang Wen2 Jian Sun2 1 University of Science and Technology of China 2 Microsoft Research Asia Abstract Inverted indexing is a popular non-exhaustive solution to large scale search. An inverted file is built by a quantizer such as k-means or a tree structure. It has

  18. Summary of Inverter Technologies Prepared for the

    E-print Network

    Summary of Inverter Technologies Prepared for the U.S. Department of Energy Office of Electricity Program Subtask 3.1 Photovoltaic Systems: Report 2 Summary of Inverter Technologies Submitted by Hawai agency thereof. #12;1 Summary of Inverter Technologies TableofContents 1. Introduction

  19. On Optimal Inverters Department of Computer Science

    E-print Network

    Chen, Yijia

    On Optimal Inverters Yijia Chen Department of Computer Science Shanghai Jiaotong University yijia.flum@math.uni-freiburg.de Abstract Leonid Levin showed that every algorithm computing a function has an optimal inverter. Recently. An inverter I of F is an algorithm that for all y in the range of F computes a preimage I(y) of y, i.e., F

  20. On Optimal Inverters Department of Computer Science

    E-print Network

    Chen, Yijia

    On Optimal Inverters Yijia Chen Department of Computer Science Shanghai Jiaotong University yijia.flum@math.uni­freiburg.de Abstract Leonid Levin showed that every algorithm computing a function has an optimal inverter. Recently. An inverter I of F is an algorithm that for all y in the range of F computes a preimage I(y) of y, i.e., F

  1. Invertibility of random matrices M. Rudelson

    E-print Network

    Weinberger, Hans

    Invertibility of random matrices M. Rudelson We will discuss several recent developments related to invertibility and spectral properties of large random matrices. Consider an n Ã? n matrix, whose values are independent identically distributed random variables. The invertibility questions can be roughly divided

  2. AN "AC INDUCTOR" BASED GRID CONNECTED INVERTER

    E-print Network

    sourcing inverters where the small disturbance at the line voltage may lead to current run away inverters, most of them share a common feature - their outputs are basically voltage sources. Consequently, is to apply an inverter with an Output Current Sourcing (OCS) behavior rather than the voltage sourcing one

  3. Parallel operation of voltage source inverters

    Microsoft Academic Search

    T. Kawabata; S. Higashino

    1988-01-01

    Parallel operating systems of voltage source inverters with other inverters or with the utility source are sensitive to disturbances from the load or other sources and can easily be damaged by overcurrent. Thus extremely careful attention should be given to the system design of parallel operating inverters. Types of system configuration, control methods, and means of protection against failure are

  4. Design methodologies for soft switched inverters

    Microsoft Academic Search

    Deepakaraj M. Divan; Giri Venkataramanan; Rik W. A. A. DeDoncker

    1993-01-01

    A detailed design methodology for soft-switched inverters is presented. The actively clamped resonant DC link and the resonant pole inverters are taken as illustrative design examples with detailed enumeration of component design rules, switching loss calculations, and system optimization. The soft-switched circuits are then compared with a conventional hard-switched voltage source inverter under identical operating conditions

  5. An Integrated Approach to Control the Quality Level of Multi-user Sessions

    E-print Network

    Monteiro, Edmundo

    Performance. Keywords Content distribution; QoS Mapping; QoS Adaptation; Network Resource Allocation. 1 of network capabilities and re-routing, which can be generated by handovers or link/node failures. The above challenges require more attention when session content is sent to multiple users (called multi-user sessions

  6. A Case Study of System Level Specification and Software Synthesis of Multi-mode Multimedia Terminal

    E-print Network

    Ha, Soonhoi

    @iris.snu.ac.kr ABSTRACT In this paper, we specify the behavior of a multi-mode mul- timedia terminal (MMMT) using block. The MMMT system consists of several real-time tasks for signal processing and control tasks to manage task controlscheduling control parameter deliveryparameter delivery Muti-mode Multimedia Terminal System Figure 1. MMMT

  7. Refinement and validation of a multi-level assessment method for Mid-Atlantic tidal wetlands

    E-print Network

    , an inventory of existing wetland resources and their biological condition, is the necessary first step. Although conscious efforts are underway in Delaware, Maryland, Pennsylvania and Virginia to inventory with the current extent and condition of tidal wetland resources, we have developed an inventory and multi

  8. Membrane fusion and inverted phases

    SciTech Connect

    Ellens, H.; Siegel, D.P.; Alford, D.; Yeagle, P.L.; Boni, L.; Lis, L.J.; Quinn, P.J.; Bentz, J. (Univ. of California, San Francisco (USA))

    1989-05-02

    We have found a correlation between liposome fusion kinetics and lipid phase behavior for several inverted phase forming lipids. N-Methylated dioleoylphosphatidylethanolamine (DOPE-Me), or mixtures of dioleoylphosphatidylethanolamine (DOPE) and dioleoylphosphatidylcholine (DOPC), will form an inverted hexagonal phase (HII) at high temperatures (above TH), a lamellar phase (L alpha) at low temperatures, and an isotropic/inverted cubic phase at intermediate temperatures, which is defined by the appearance of narrow isotropic {sup 31}P NMR resonances. The phase behavior has been verified by using high-sensitivity DSC, {sup 31}P NMR, freeze-fracture electron microscopy, and X-ray diffraction. The temperature range over which the narrow isotropic resonances occur is defined as delta TI, and the range ends at TH. Extruded liposomes (approximately 0.2 microns in diameter) composed of these lipids show fusion and leakage kinetics which are strongly correlated with the temperatures of these phase transitions. At temperatures below delta TI, where the lipid phase is L alpha, there is little or no fusion, i.e., mixing of aqueous contents, or leakage. However, as the temperature reaches delta TI, there is a rapid increase in both fusion and leakage rates. At temperatures above TH, the liposomes show aggregation-dependent lysis, as the rapid formation of HII phase precursors disrupts the membranes. We show that the correspondence between the fusion and leakage kinetics and the observed phase behavior is easily rationalized in terms of a recent kinetic theory of L alpha/inverted phase transitions. In particular, it is likely that membrane fusion and the L alpha/inverted cubic phase transition proceed via a common set of intermembrane intermediates.

  9. Multi-Level Factors Affecting Entry into and Engagement in the HIV Continuum of Care in Iringa, Tanzania

    PubMed Central

    Layer, Erica H.; Kennedy, Caitlin E.; Beckham, Sarah W.; Mbwambo, Jessie K.; Likindikoki, Samuel; Davis, Wendy W.; Kerrigan, Deanna L.; Brahmbhatt, Heena

    2014-01-01

    Progression through the HIV continuum of care, from HIV testing to lifelong retention in antiretroviral therapy (ART) care and treatment programs, is critical to the success of HIV treatment and prevention efforts. However, significant losses occur at each stage of the continuum and little is known about contextual factors contributing to disengagement at these stages. This study sought to explore multi-level barriers and facilitators influencing entry into and engagement in the continuum of care in Iringa, Tanzania. We used a mixed-methods study design including facility-based assessments and interviews with providers and clients of HIV testing and treatment services; interviews, focus group discussions and observations with community-based providers and clients of HIV care and support services; and longitudinal interviews with men and women living with HIV to understand their trajectories in care. Data were analyzed using narrative analysis to identify key themes across levels and stages in the continuum of care. Participants identified multiple compounding barriers to progression through the continuum of care at the individual, facility, community and structural levels. Key barriers included the reluctance to engage in HIV services while healthy, rigid clinic policies, disrespectful treatment from service providers, stock-outs of supplies, stigma and discrimination, alternate healing systems, distance to health facilities and poverty. Social support from family, friends or support groups, home-based care providers, income generating opportunities and community mobilization activities facilitated engagement throughout the HIV continuum. Findings highlight the complex, multi-dimensional dynamics that individuals experience throughout the continuum of care and underscore the importance of a holistic and multi-level perspective to understand this process. Addressing barriers at each level is important to promoting increased engagement throughout the continuum. PMID:25119665

  10. Sinusoidal Based Step Pulse PWM Method in Cascade Multilevel Inverters

    Microsoft Academic Search

    Nguyen Van Nho; Hong Hee Lee; Nguyen Huy Khuong

    2006-01-01

    Recently, an on-line step pulse PWM method has been introduced for cascade multilevel inverters. The simplicity of this method was derived from the principle control between two defined trajectories. For achieving good output performances, several exact angular sets are needed to be determined in advance by solving the trigonometric equations. If the number of step levels increases, then solving the

  11. A public health framework to translate risk factors related to political violence and war into multi-level preventive interventions.

    PubMed

    De Jong, Joop T V M

    2010-01-01

    Political violence, armed conflicts and human rights violations are produced by a variety of political, economic and socio-cultural factors. Conflicts can be analyzed with an interdisciplinary approach to obtain a global understanding of the relative contribution of risk and protective factors. A public health framework was designed to address these risk factors and protective factors. The framework resulted in a matrix that combined primary, secondary and tertiary interventions with their implementation on the levels of the society-at-large, the community, and the family and individual. Subsequently, the risk and protective factors were translated into multi-sectoral, multi-modal and multi-level preventive interventions involving the economy, governance, diplomacy, the military, human rights, agriculture, health, and education. Then the interventions were slotted in their appropriate place in the matrix. The interventions can be applied in an integrative form by international agencies, governments and non-governmental organizations, and molded to meet the requirements of the historic, political-economic and socio-cultural context. The framework maps the complementary fit among the different actors while engaging themselves in preventive, rehabilitative and reconstructive interventions. The framework shows how the economic, diplomatic, political, criminal justice, human rights, military, health and rural development sectors can collaborate to promote peace or prevent the aggravation or continuation of violence. A deeper understanding of the association between risk and protective factors and the developmental pathways of generic, country-specific and culture-specific factors leading to political violence is needed. PMID:19883967

  12. An empirical study of statistical properties of variance partition coefficients for multi-level logistic regression models

    USGS Publications Warehouse

    Li, J.; Gray, B.R.; Bates, D.M.

    2008-01-01

    Partitioning the variance of a response by design levels is challenging for binomial and other discrete outcomes. Goldstein (2003) proposed four definitions for variance partitioning coefficients (VPC) under a two-level logistic regression model. In this study, we explicitly derived formulae for multi-level logistic regression model and subsequently studied the distributional properties of the calculated VPCs. Using simulations and a vegetation dataset, we demonstrated associations between different VPC definitions, the importance of methods for estimating VPCs (by comparing VPC obtained using Laplace and penalized quasilikehood methods), and bivariate dependence between VPCs calculated at different levels. Such an empirical study lends an immediate support to wider applications of VPC in scientific data analysis.

  13. Thermal Study of Inverter Components: Preprint

    SciTech Connect

    Sorensen, N. R.; Thomas, E. V.; Quintana, M. A.; Barkaszi, S.; Rosenthal, A.; Zhang, Z.; Kurtz, S.

    2012-06-01

    Thermal histories of inverter components were collected from operating inverters from several manufacturers and three locations. The data were analyzed to determine thermal profiles, the dependence on local conditions, and to assess the effect on inverter reliability. Inverter temperatures were shown to increase with the power dissipation of the inverters, follow diurnal and annual cycles, and have a dependence on wind speed. An accumulated damage model was applied to the temperature profiles and an example of using these data to predict reliability was explored.

  14. A novel alignment mechanism employing orthogonal connected multi-layered flexible hinges for both leveling and centering.

    PubMed

    Zhao, Jian; Wang, Hongxi; Gao, Renjing; Hu, Ping; Yang, Yintang

    2012-06-01

    To eliminate the effects of motion coupling for measuring cylindrical work pieces, a novel alignment mechanism integrating functions of both leveling and centering is designed and fabricated by introducing multi-layered orthogonal connected flexible hinges as the key supporting and joining elements. Different from traditional leveling mechanisms with many separate parts fabricated together, all of the flexible hinges were integrated in one three-dimensioned machining part without assembling process, and thus synchronously simplifying the structure and reducing assembly errors. Based on the screw theory, the mathematic model of the proposed alignment mechanism is established for any resolution requirements depending on screw characteristics. A millimeter-sized device is fabricated with the alignment precision of 1.0 ?m for centering within the range of ±1 mm and 1 in. for leveling within ±1°. The experiment results are in very close agreement to those obtained by simulation, which validate the feasibility of introducing multi-layered orthogonal flexible hinges in the centering and leveling mechanisms. PMID:22755657

  15. The chromospheric Ca II and Mg II radiative losses in late-type stars: a computational comparison between two-level and multi-level atomic models

    NASA Astrophysics Data System (ADS)

    Fawzy, Diaa E.

    2015-06-01

    In the current study we present radiation correction factors to compute the radiative losses by Mg II and Ca II ions during the process of constructing theoretical models for the chromospheres in late-type stars (spectral type in the range F5V-K8V). We combine the two-level atom approach with the multi-level atom method to accurately compute the radiation correction factors. The procedure is fast and reasonably accurate to be implemented in the time-dependent computations. In the current computations we implement what is called pseudo-partial frequency redistribution and the time-dependent ionization in regard to hydrogen. The radiative correction factors for Mg II show very slight variation for the different spectral types with average value of 1.5. The values we obtained for Ca II show very strong dependence on spectral types and the basic parameters, with values range between 5.58 to 4.22 for F5V and K8V spectral types, respectively. The obtained results accelerate the process of constructing theoretical model chromospheres based on mechanical heating by monochromatic and wave spectra. The current study is an initial step in establishing hybrid multi-dimensional models of stellar chromospheres.

  16. Multi-Level Virtual Machine Debugging using the Java Platform Debugger Architecture

    E-print Network

    Mössenböck, Hanspeter

    , stack and register values. Debuggers for low-level languages such as C and C++, on the other hand, have direct access only to low-level information from which they must syn- thesize higher-level views- independent debugger interfaces but which also interacts with the exe- cution environment in terms of low-level

  17. Decentralized multi-level uncapacitated lot-sizing by automated negotiation

    Microsoft Academic Search

    Jörg Homberger

    2010-01-01

    An automated negotiation mechanism for decentralized production coordination is presented and evaluated. The coordination\\u000a problem contains a set of self-interested software agents, representing the production facilities of a supply chain, searching\\u000a for a mutually agreeable production plan, while taking private information into account. The negotiation mechanism is applied\\u000a and evaluated using a multi-facility production coordination problem, which is a reformulation

  18. Combining Low-Level and Summary Representations of Opinions for Multi-Perspective Question Answering

    Microsoft Academic Search

    Claire Cardie; Janyce Wiebe; Theresa Wilson; Diane J. Litman

    2003-01-01

    While much recent progress has been made in research on fact-based question answering (Voorhees and Dice, 2000; Voorhees, 2001), our work aims to extend question-answering re- search in a different direction — to handle multi-perspective question-answering tasks, i.e. ques- tion-answering tasks that require an ability to find and organize opinions in text. In particular, this paper proposes an approach to

  19. Simulation of Multi-Robot Teams with Flexible Level of Detail

    Microsoft Academic Search

    Martin Friedmann; Karen Petersen; Oskar Von Stryk

    2008-01-01

    A key methodology for the development of autonomous robots is testing using simulated robot motion and sensing systems. An impor- tant issue when simulating teams of heterogeneous autonomous robots is performance versus accuracy. In this paper the multi-robot-simulation framework (MuRoSimF) is presented which allows the exible and trans- parent exchange and combination of the algorithms used for the simula- tion

  20. Multi-scale environmental accounting: methodological lessons from the application of NAMEA at sub-national levels.

    PubMed

    Dalmazzone, Silvana; La Notte, Alessandra

    2013-11-30

    Extending the application of integrated environmental and economic accounts from the national to the local level of government serves several purposes. They can be used not only as an instrument for communicating on the state of the environment and reporting the results of policies, but also as an operational tool - for setting the objectives and designing policies - if made available to the local authorities who have responsibility over the administration of natural resources, land use and conservation policies. The aim of the paper is to test the feasibility of applying hybrid flow accounts at the intermediate and local government levels. As an illustration, NAMEA for air emissions and wastes is applied to a Region, a Province and a Municipality, thus covering the three nested levels of local government in Italy. The study identifies the main issues raised by multi-scale environmental accounting and provides an applied discussion of feasible solutions. PMID:24141065

  1. Fabrication of organic complementary inverter

    NASA Astrophysics Data System (ADS)

    Yadav, Sarita; Ghosh, Subhasis

    2012-10-01

    We have fabricated organic complementary inverter comprised of p-channel copper phthalocyanine(CuPc) and n-channel hexadecafluoro phthalocyanine (F16CuPc) based organic thin film transistors (OTFTs) with single Cu metal electrode for both type of OTFTs. The work function of Cu is nearly equal to the highest occupied molecular orbital (HOMO) of CuPc and lowest unoccupied molecular orbital (LUMO) of F16CuPc hence it can be used as source/drain electrode for both type of OTFTs which shows field effect mobilities of CuPc and F16CuPc based OTFTs are 1.27x10-3cm2V-1S-1 and 3.30x10-4cm2V- 1S-1 respectively. Voltage transfer characteristics of complementary inverter show high noise margins and switching voltage around VDD/2 with a maximum gain in the order of 20.

  2. A Switched-Capacitor Lossless Inductor ZCS Snubber-Assisted Series Load Resonant High Frequency Inverter with Dual Mode Pulse Modulation Scheme

    Microsoft Academic Search

    Khairy Fathy; T. Okude; H. Omori; Hyun Woo Lee; M. Nakaoka

    2006-01-01

    In this paper, a novel type auxiliary active edge resonant snubber assisted zero current soft switching pulse modulation series load resonant inverter using IGBT power modules is proposed for cost effective consumer high-frequency induction heating (IH) appliances. Its operating principle in steady state is described by using each switching mode equivalent operating circuits. The new multi resonant high-frequency inverter with

  3. Effective switching frequency multiplier inverter

    DOEpatents

    Su, Gui-Jia (Oak Ridge, TN); Peng, Fang Z. (Okemos, MI)

    2007-08-07

    A switching frequency multiplier inverter for low inductance machines that uses parallel connection of switches and each switch is independently controlled according to a pulse width modulation scheme. The effective switching frequency is multiplied by the number of switches connected in parallel while each individual switch operates within its limit of switching frequency. This technique can also be used for other power converters such as DC/DC, AC/DC converters.

  4. The Inverted Snow Globe Shadow

    NASA Astrophysics Data System (ADS)

    Ribeiro, Jair Lúcio Prados

    2015-01-01

    Our high school optics course finishes with an assignment that students usually appreciate. They must take pictures of everyday situations representing optical phenomena such as reflection, refraction, or dispersion, and post them on Instagram.1 When the photos were presented to the class, one student revealed an intriguing photo, similar to Fig. 1, showing a snow globe exposed to sunlight and its inverted shadow. This paper offers an explanation of the problem, which occurs due to light refraction from the globe.

  5. Care pathways across the primary-hospital care continuum: using the multi-level framework in explaining care coordination

    PubMed Central

    2013-01-01

    Background Care pathways are widely used in hospitals for a structured and detailed planning of the care process. There is a growing interest in extending care pathways into primary care to improve quality of care by increasing care coordination. Evidence is sparse about the relationship between care pathways and care coordination. The multi-level framework explores care coordination across organizations and states that (inter)organizational mechanisms have an effect on the relationships between healthcare professionals, resulting in quality and efficiency of care. The aim of this study was to assess the extent to which care pathways support or create elements of the multi-level framework necessary to improve care coordination across the primary - hospital care continuum. Methods This study is an in-depth analysis of five existing local community projects located in four different regions in Flanders (Belgium) to determine whether the available empirical evidence supported or refuted the theoretical expectations from the multi-level framework. Data were gathered using mixed methods, including structured face-to-face interviews, participant observations, documentation and a focus group. Multiple cases were analyzed performing a cross case synthesis to strengthen the results. Results The development of a care pathway across the primary-hospital care continuum, supported by a step-by-step scenario, led to the use of existing and newly constructed structures, data monitoring and the development of information tools. The construction and use of these inter-organizational mechanisms had a positive effect on exchanging information, formulating and sharing goals, defining and knowing each other’s roles, expectations and competences and building qualitative relationships. Conclusion Care pathways across the primary-hospital care continuum enhance the components of care coordination. PMID:23919518

  6. Evaluation of empirical mode decomposition for quantifying multi-decadal variations and acceleration in sea level records

    NASA Astrophysics Data System (ADS)

    Chambers, D. P.

    2015-03-01

    The ability of empirical mode decomposition (EMD) to extract multi-decadal variability from sea level records is tested using three simulations: one based on a series of purely sinusoidal modes, one based on scaled climate indices of El Niño and the Pacific decadal oscillation (PDO), and the final one including a single month with an extreme sea level event. All simulations include random noise of similar variance to high-frequency variability in the San Francisco tide gauge record. The intrinsic mode functions (IMFs) computed using EMD were compared to the prescribed oscillations. In all cases, the longest-period modes are significantly distorted, with incorrect amplitudes and phases. This affects the estimated acceleration computed from the longest periodic IMF. In these simulations, the acceleration was underestimated in the case with purely sinusoidal modes, and overestimated by nearly 100% in the case with prescribed climate modes. Additionally, in all cases, extra low-frequency modes uncorrelated with the prescribed variability are found. These experiments suggest that using EMD to identify multi-decadal variability and accelerations in sea level records should be used with caution.

  7. Perturbational treatment of spin-orbit coupling for generally applicable high-level multi-reference methods

    NASA Astrophysics Data System (ADS)

    Mai, Sebastian; Müller, Thomas; Plasser, Felix; Marquetand, Philipp; Lischka, Hans; González, Leticia

    2014-08-01

    An efficient perturbational treatment of spin-orbit coupling within the framework of high-level multi-reference techniques has been implemented in the most recent version of the Columbus quantum chemistry package, extending the existing fully variational two-component (2c) multi-reference configuration interaction singles and doubles (MRCISD) method. The proposed scheme follows related implementations of quasi-degenerate perturbation theory (QDPT) model space techniques. Our model space is built either from uncontracted, large-scale scalar relativistic MRCISD wavefunctions or based on the scalar-relativistic solutions of the linear-response-theory-based multi-configurational averaged quadratic coupled cluster method (LRT-MRAQCC). The latter approach allows for a consistent, approximatively size-consistent and size-extensive treatment of spin-orbit coupling. The approach is described in detail and compared to a number of related techniques. The inherent accuracy of the QDPT approach is validated by comparing cuts of the potential energy surfaces of acrolein and its S, Se, and Te analoga with the corresponding data obtained from matching fully variational spin-orbit MRCISD calculations. The conceptual availability of approximate analytic gradients with respect to geometrical displacements is an attractive feature of the 2c-QDPT-MRCISD and 2c-QDPT-LRT-MRAQCC methods for structure optimization and ab inito molecular dynamics simulations.

  8. Gripper deploying and inverting linkage

    DOEpatents

    Minichan, R.L.; Killian, M.A.

    1993-03-02

    An end effector deploying and inverting linkage. The linkage comprises an air cylinder mounted in a frame or tube, a sliding bracket next to the air cylinder, a stopping bracket depending from the frame and three, pivotally-attached links that are attached to the end effector and to each other in such a way as to be capable of inverting the end effector and translating it laterally. The first of the three links is a straight element that is moved up and down by the shaft of the air cylinder. The second link is attached at one end to the stopping bracket and to the side of the end effector at the other end. The first link is attached near the middle of the second, sharply angled link so that, as the shaft of the air cylinder moves up and down, the second link rotates about an axis perpendicular to the frame and inverts and translates the end effector. The rotation of the second link is stopped at both ends when the link engages stops on the stopping bracket. The third link, slightly angled, is attached to the sliding bracket at one end and to the end of the end effector at the other. The third helps to control the end effector in its motion.

  9. Multi-model predictive control method for nuclear steam generator water level

    Microsoft Academic Search

    Ke Hu; Jingqi Yuan

    2008-01-01

    The dynamics of a nuclear steam generator (SG) is very different according to the power levels and changes as time goes on. Therefore, it is an intractable as well as challenging task to improve the water level control system of the SG. In this paper, a robust model predictive control (RMPC) method is developed for the level control problem. Based

  10. Continuum Level Formulation and Implementation of a Multi-scale Model for Vanadium

    SciTech Connect

    Lawrence Livermore National Laboratory

    2009-08-17

    A multi-scale approach is used to construct a continuum strength model for vanadium. The model is formulated assuming plastic deformation by dislocation motion and strain hardening due to dislocation interactions. Dislocation density is adopted as the state variable in the model. Information from molecular statics, molecular dynamics and dislocation dynamics simulations is combined to create kinetic relations for dislocation motion, strain hardening relations and evolution equations for the dislocation density. Implicit time integration of the constitutive equations is described in the context of implementation in a finite element code. Results are provided illustrating the strain, strain rate, temperature and pressure dependence of the constitutive model.

  11. Repetition probability effects for inverted faces.

    PubMed

    Grotheer, Mareike; Hermann, Petra; Vidnyánszky, Zoltán; Kovács, Gyula

    2014-11-15

    It has been shown, that the repetition related reduction of the blood-oxygen level dependent (BOLD) signal is modulated by the probability of repetitions (P(rep)) for faces (Summerfield et al., 2008), providing support for the predictive coding (PC) model of visual perception (Rao and Ballard, 1999). However, the stage of face processing where repetition suppression (RS) is modulated by P(rep) is still unclear. Face inversion is known to interrupt higher level configural/holistic face processing steps and if modulation of RS by P(rep) takes place at these stages of face processing, P(rep) effects are expected to be reduced for inverted when compared to upright faces. Therefore, here we aimed at investigating whether P(rep) effects on RS observed for face stimuli originate at the higher-level configural/holistic stages of face processing by comparing these effects for upright and inverted faces. Similarly to previous studies, we manipulated P(rep) for pairs of stimuli in individual blocks of fMRI recordings. This manipulation significantly influenced repetition suppression in the posterior FFA, the OFA and the LO, independently of stimulus orientation. Our results thus reveal that RS in the ventral visual stream is modulated by P(rep) even in the case of face inversion and hence strongly compromised configural/holistic face processing. An additional whole-brain analysis could not identify any areas where the modulatory effect of probability was orientation specific either. These findings imply that P(rep) effects on RS might originate from the earlier stages of face processing. PMID:25123974

  12. An adaptive framework to differentiate receiving water quality impacts on a multi-scale level.

    PubMed

    Blumensaat, F; Tränckner, J; Helm, B; Kroll, S; Dirckx, G; Krebs, P

    2013-01-01

    The paradigm shift in recent years towards sustainable and coherent water resources management on a river basin scale has changed the subject of investigations to a multi-scale problem representing a great challenge for all actors participating in the management process. In this regard, planning engineers often face an inherent conflict to provide reliable decision support for complex questions with a minimum of effort. This trend inevitably increases the risk to base decisions upon uncertain and unverified conclusions. This paper proposes an adaptive framework for integral planning that combines several concepts (flow balancing, water quality monitoring, process modelling, multi-objective assessment) to systematically evaluate management strategies for water quality improvement. As key element, an S/P matrix is introduced to structure the differentiation of relevant 'pressures' in affected regions, i.e. 'spatial units', which helps in handling complexity. The framework is applied to a small, but typical, catchment in Flanders, Belgium. The application to the real-life case shows: (1) the proposed approach is adaptive, covers problems of different spatial and temporal scale, efficiently reduces complexity and finally leads to a transparent solution; and (2) water quality and emission-based performance evaluation must be done jointly as an emission-based performance improvement does not necessarily lead to an improved water quality status, and an assessment solely focusing on water quality criteria may mask non-compliance with emission-based standards. Recommendations derived from the theoretical analysis have been put into practice. PMID:23168645

  13. A single-phase embedded Z-source DC-AC inverter.

    PubMed

    Kim, Se-Jin; Lim, Young-Cheol

    2014-01-01

    In the conventional DC-AC inverter consisting of two DC-DC converters with unipolar output capacitors, the output capacitor voltages of the DC-DC converters must be higher than the DC input voltage. To overcome this weakness, this paper proposes a single-phase DC-AC inverter consisting of two embedded Z-source converters with bipolar output capacitors. The proposed inverter is composed of two embedded Z-source converters with a common DC source and output AC load. Though the output capacitor voltages of the converters are relatively low compared to those of a conventional inverter, an equivalent level of AC output voltages can be obtained. Moreover, by controlling the output capacitor voltages asymmetrically, the AC output voltage of the proposed inverter can be higher than the DC input voltage. To verify the validity of the proposed inverter, experiments were performed with a DC source voltage of 38 V. By controlling the output capacitor voltages of the converters symmetrically or asymmetrically, the proposed inverter can produce sinusoidal AC output voltages. The experiments show that efficiencies of up to 95% and 97% can be achieved with the proposed inverter using symmetric and asymmetric control, respectively. PMID:25133241

  14. High-Frequency Link: A Solution for Using Only One DC Source in Asymmetric Cascaded Multilevel Inverters

    Microsoft Academic Search

    Javier Pereda; Juan Dixon

    2011-01-01

    Multilevel inverters are in state-of-the-art power con- version systems due to their improved voltage and current wave- forms. Cascaded H-bridge (CHB) multilevel inverters have been considered as an alternative in the medium-voltage converter mar- ket and experimental electric vehicles. Their variant, the asymmet- rical CHB (ACHB) inverter, optimizes the number of voltage levels by using dc supplies with different voltages.

  15. A formula for low achievement: using multi-level models to understand the impact of individual level effects and school level effects on mathematics achievement 

    E-print Network

    Parks, Kathrin Ann

    2004-09-30

    The following study utilizes data from the High School and Beyond Study in order to predict mathematics achievement using both student characteristics and school level characteristics. Utilizing Hierarchical Linear Modeling, this study extends...

  16. Multi-level consistency tests in paleointensity determinations from the welded tuffs of the Aso pyroclastic-flow deposits

    NASA Astrophysics Data System (ADS)

    Mochizuki, Nobutatsu; Maruuchi, Toru; Yamamoto, Yuhji; Shibuya, Hidetoshi

    2013-10-01

    We have performed multi-level consistency tests in an LTD-DHT Shaw paleointensity study on the welded tuffs of the Aso pyroclastic-flow deposits (Aso-1, Aso-2, Aso-3, and Aso-4) in order to obtain reliable mean paleointensities from each unit. For a unit-level consistency test, we collected samples at three or more sites in each unit. To enhance a site-level consistency test, we conducted paleointensity experiments on both whole-rock and glass samples from the same sites. Thermal demagnetization curves of the samples indicate that the main magnetic carrier is titanium-poor titanomagnetite to pure magnetite. Hysteresis parameters are different among the sites of the same units. Also, differences in unblocking spectra and hysteresis parameters are recognized between the whole-rock and glass samples from the same sites. Therefore, these samples of various properties are expected to work effectively for multi-level consistency test. Twenty-nine out of 65 whole-rock samples and 10 out of 31 glass samples gave accepted paleointensity results. At the site-level, consistency of paleointensity estimates is observed with the exception of one site. Two paleointensity estimates from glass samples of a site of Aso-4 are inconsistent and are excluded from further analysis. At the unit-level, consistency or inconsistency among the sites is observed for individual units. For Aso-1, inconsistency in paleointensity estimates among the sites is observed and we can recognize more reliable results from two sites. For Aso-2, consistency in paleointensity estimates from glass and whole-rock samples supports the acceptance of a site. For Aso-3, all paleointensity estimates from two sites are thought to be reliable because consistency between the site-means of the two sites as well as site-level consistency between the glass and whole-rock samples for each site is recognized. For Aso-4, some difference among the sites is observed, but there is no obvious reason to exclude the results of particular sites. Overall, both the site-level and unit-level consistency checks work effectively in these samples which confirm the reliability of the paleointensity estimates or highlights the erroneous ones. On the basis of the reliable paleointensity estimates, unit-mean values are obtained as 24.9 ± 2.2 (1?) ?T (N = 9) for Aso-1, 22.9 ± 1.6 ?T (N = 5) for Aso-2, 28.3 ± 3.4 ?T (N = 10) for Aso-3, and 40.1 ± 6.2 ?T (N = 7) for Aso-4.

  17. Study on PID neural-network-based inverter space-vector pulse width modulation strategy

    Microsoft Academic Search

    Bo You; Fengjing Zhang

    2008-01-01

    A PID neural-network-based space-vector pulse width modulation (SVPWM) for a three-level inverter is proposed in this paper. A three-level inverter has lots of switching states about the vectors, and the implementation of modulation algorithm is considerably complex. In the proposed design, fast implementation of SVPWM algorithm is realized based on PID neural network instead of conventional neural network. A three-layer

  18. Study of turbulence of Lower Hybrid Drift Instability origin with the Multi Level Multi Domain semi-implicit adaptive PIC method

    NASA Astrophysics Data System (ADS)

    Innocenti, Maria Elena; Beck, Arnaud; Markidis, Stefano; Lapenta, Giovanni

    2015-04-01

    We study turbulence generated by the Lower Hybrid Drift Instability (LHDI [1]) in the terrestrial magnetosphere. The problem is not only of interest per se, but also for the implications it can have for the so-called turbulent reconnection. The LHDI evolution is simulated with the PIC Multi Level Multi Domain code Parsek2D-MLMD [2,3], which simulates different parts of the domain with different spatial and temporal resolutions. This allows to satisfy, at a low computing cost, the two necessary requirements for LHDI turbulence simulations: 1) a large domain, to capture the high wavelength branch of the LHDI and of the secondary kink instability and 2) high resolution, to cover the high wavenumber part of the power spectrum and to capture the wavenumber at which the turbulent cascade ends. The turbulent cascade proceeds seamlessly from the coarse (low resolution) to the refined (high resolution) grid, the only one resolved enough to capture its end, which is studied here and related to wave-particle interaction processes. We also comment upon the role of smoothing (a common technique used in PIC simulations to reduce particle noise, [4]) in simulations of turbulence and on how its effects on power spectra may be easily mistaken, in absence of accurate convergence studies, for the end of the inertial range. [1] P. Gary, Theory of space plasma microinstabilities, Cambridge Atmospheric and Space Science Series, 2005. [2] M. E. Innocenti, G. Lapenta, S. Markidis, A. Beck, A. Vapirev, Journal of Computational Physics 238 (2013) 115 - 140. [3] M. E. Innocenti, A. Beck, T. Ponweiser, S. Markidis, G. Lapenta, Computer Physics Communications (accepted) (2014). [4] C. K. Birdsall, A. B. Langdon, Plasma physics via computer simulation, Taylor and Francis, 2004.

  19. A Biomimetic Collagen-Apatite Scaffold with a Multi-Level Lamellar Structure for Bone Tissue Engineering

    PubMed Central

    Xia, Z.; Villa, M. M.; Wei, M.

    2014-01-01

    Collagen-apatite (Col-Ap) scaffolds have been widely employed for bone tissue engineering. We fabricated a Col-Ap scaffold with a unique multi-level lamellar structure consisting of co-aligned micro and macro pores. The basic building blocks of this scaffold are bone-like mineralized collagen fibers developed via a biomimetic self-assembly process in a collagen-containing modified simulated body fluid (m-SBF). This biomimetic method preserves the structural integrity and great tensile strength of collagen by reinforcing the collagen hydrogel with apatite nano-particles. Unidirectional aligned macro pores with a size of 63.8 to 344 ?m are created by controlling the freezing rate and direction. The thickness of Col-Ap lamellae can be adjusted in the range 3.6 to 23 ?m depending on the self-compression time. Furthermore, the multi-level lamellar structure has led to a twelve-fold increase in Young's modulus and a two-fold increase in the compression modulus along the aligned direction compared to a scaffold of the same composition with an isotropic equiaxed pore structure. Moreover, this novel lamellar scaffold supports the attachment and spreading of MC3T3-E1osteoblasts. Therefore, owing to the biomimetic composition, tunable structure, improved mechanical strength, and good biocompatibility of this novel scaffold, it has great potential to be used in bone tissue engineering applications. PMID:24999428

  20. Fabrication of the multi-level phase type hologram for display using the laser direct write lithography system

    NASA Astrophysics Data System (ADS)

    Nakano, Seiji; Nakahara, Sumio; Singubara, Shoso

    2012-03-01

    Recently, the demand to the diffractive optical element (DOE) is increasing with the developments in the technology. We created a relative large holographic optical element (HOE) with same course of production of the DOE. To make the person who is situated on the long distance recognize image data using the hologram, the hologram must have bright image reconstruction ability and a high SN ratio. Therefore, we made the multi-level phase type hologram for the former and measured the optical intensity of the reproduction image. For an evaluation method of the diffraction efficiency, we used 2-, 4-, and 8-level phase type Fresnel Zone Plate (FZP). Because it supposed that the amount of object was large, it adopted a computer-generated hologram (CGH). Also, it used laser direct write lithography system that has the feature of high-resolution drawing, high-speed drawing, and a high accuracy positioning system, for the making of hologram.

  1. A Model of Adding Relations in Multi-levels to a Formal Organization Structure with Two Subordinates

    NASA Astrophysics Data System (ADS)

    Sawada, Kiyoshi; Amano, Kazuyuki

    2009-10-01

    This paper proposes a model of adding relations in multi-levels to a formal organization structure with two subordinates such that the communication of information between every member in the organization becomes the most efficient. When edges between every pair of nodes with the same depth in L (L = 1, 2, …, H) levels are added to a complete binary tree of height H, an optimal set of depths {N1, N2, …, NL} (H?N1>N2> …>NL?1) is obtained by maximizing the total shortening path length which is the sum of shortening lengths of shortest paths between every pair of all nodes in the complete binary tree. It is shown that {N1, N2, …, NL}* = {H, H-1, …, H-L+1}.

  2. Commodity multi-processor systems in the ATLAS level-2 trigger

    SciTech Connect

    Abolins, M.; Blair, R.; Bock, R.; Bogaerts, A.; Dawson, J.; Ermoline, Y.; Hauser, R.; Kugel, A.; Lay, R.; Muller, M.; Noffz, K.-H.; Pope, B.; Schlereth, J.; Werner, P.

    2000-05-23

    Low cost SMP (Symmetric Multi-Processor) systems provide substantial CPU and I/O capacity. These features together with the ease of system integration make them an attractive and cost effective solution for a number of real-time applications in event selection. In ATLAS the authors consider them as intelligent input buffers (active ROB complex), as event flow supervisors or as powerful processing nodes. Measurements of the performance of one off-the-shelf commercial 4-processor PC with two PCI buses, equipped with commercial FPGA based data source cards (microEnable) and running commercial software are presented and mapped on such applications together with a long-term program of work. The SMP systems may be considered as an important building block in future data acquisition systems.

  3. METRICFORENSICS: A Multi-Level Approach for Mining Volatile Graphs Keith Henderson

    E-print Network

    signifi- cant research interest is the cyber-security domain, where inter- net communication traces-level "drill down" approach, a collection of user-selected graph metrics, and a col- lection of analysis techniques. At each successive level, more so- phisticated metrics are computed and the graph is viewed

  4. A problem for RST: the need for multi-level discourse analysis

    Microsoft Academic Search

    Johanna D. Moore; Martha E. Pollack

    1992-01-01

    this paper, we focus ontwo levels of analysis. The first involves the relation between the information conveyed inconsecutive elements of a coherent discourse. Thus, for example, one utterance may describean event that can be presumed to be the cause of another event described in the subsequentutterance. This causal relation is at what we will call the informational level. The secondlevel

  5. Multilevel Inverters for Electric Vehicle Applications

    SciTech Connect

    Habetler, T.G.; Peng, F.Z.; Tolbert, L.M.

    1998-10-22

    This paper presents multilevel inverters as an application for all-electric vehicle (EV) and hybrid-electric vehicle (HEV) motor drives. Diode-clamped inverters and cascaded H-bridge inverters, (1) can generate near-sinusoidal voltages with only fundamental frequency switching; (2) have almost no electromagnetic interference (EMI) and common-mode voltage; and (3) make an EV more accessible/safer and open wiring possible for most of an EV'S power system. This paper explores the benefits and discusses control schemes of the cascade inverter for use as an EV motor drive or a parallel HEV drive and the diode-clamped inverter as a series HEV motor drive. Analytical, simulated, and experimental results show the superiority of these multilevel inverters for this new niche.

  6. Graph state generation with noisy mirror-inverting spin chains

    E-print Network

    S. R. Clark; A. Klein; M. Bruderer; D. Jaksch

    2007-05-24

    We investigate the influence of noise on a graph state generation scheme which exploits a mirror inverting spin chain. Within this scheme the spin chain is used repeatedly as an entanglement bus (EB) to create multi-partite entanglement. The noise model we consider comprises of each spin of this EB being exposed to independent local noise which degrades the capabilities of the EB. Here we concentrate on quantifying its performance as a single-qubit channel and as a mediator of a two-qubit entangling gate, since these are basic operations necessary for graph state generation using the EB. In particular, for the single-qubit case we numerically calculate the average channel fidelity and whether the channel becomes entanglement breaking, i.e., expunges any entanglement the transferred qubit may have with other external qubits. We find that neither local decay nor dephasing noise cause entanglement breaking. This is in contrast to local thermal and depolarizing noise where we determine a critical length and critical noise coupling, respectively, at which entanglement breaking occurs. The critical noise coupling for local depolarizing noise is found to exhibit a power-law dependence on the chain length. For two qubits we similarly compute the average gate fidelity and whether the ability for this gate to create entanglement is maintained. The concatenation of these noisy gates for the construction of a five qubit linear cluster state and a Greenberger-Horne-Zeilinger state indicates that the level of noise that can be tolerated for graph state generation is tightly constrained.

  7. Inverted Sparticle Hierarchies from Natural Particle Hierarchies

    E-print Network

    Ofer Aharony; Leon Berdichevsky; Micha Berkooz; Yonit Hochberg; Daniel Robles-Llana

    2010-10-20

    A possible resolution of the flavor puzzle is that the fermion mass hierarchy can be dynamically generated through the coupling of the first two generation fields to a strongly coupled sector, which is approximately conformally invariant and leads to large anomalous dimensions for the first two generation fields over a large range of energies. We investigate the possibility of using the same sector to also break supersymmetry. We show that this automatically gives an "inverted hierarchy" in which the first two generation squarks and sleptons are much heavier than the other superpartners. Implementing this construction generically requires some fine-tuning in order to satisfy the constraints on flavor-changing neutral currents at the same time as solving the hierarchy problem. We show that this fine-tuning can be reduced to be milder than the percent level by making some technically natural assumptions about the form of the strongly coupled sector and its couplings to the standard model.

  8. A Vulcano Expert System: Automatic Alert Level Estimation and GIS Visualization on top of a multi-parameter Data Base

    NASA Astrophysics Data System (ADS)

    Beyreuther, Moritz; Barsch, Robert; Bernsdorf, Stefan; Zakšek, Klemen; Wassermann, Joachim

    2010-05-01

    The success of volcano fast response systems including early warning of an imminent eruption lives through its connection capability to already installed monitoring systems. Also new temporary, possible wireless networks as well as combination of different raw and model data needs to be covered. In practice this means a high-dimensional, complicated (raw or already parameterised) data stream with different sampling rates and time histories that have to be stored and analysed. In the framework of the Exupery project (GEOTECHNOLOGIEN, German Ministry for Education and Research - BMBF) the SeisHub Database handles multi-parameter data resulting from modern volcano monitoring networks simultaneously. This is a quite common situation today in order to assess volcanic activity. The warning system, here a GIS and an automatic alert level estimation, connects to the data base to retrieve the relevant information. The GIS provides access to the data as well as analysis results. By overlaying various parameters in the GIS systems the expert can analyse the situation and base his/her decision easily on multi-parameter data. In addition to data interactive visualization via the GIS the alert level of the volcano is automatically estimated using a Bayesian Belief Network (BBN) approach. This allows the expert to verify his own assessment versus the automatic system. In case there are major differences, the expert can identify the origin of the difference in the graphical representation of the BBN and if necessary adapt the BBN. BBNs are chosen because of their transparency (graphical representation), flexibility, probabilistic architecture and their possibility to incorporate expert knowledge. The probabilistic architecture allows to compute a confidence measure for the given alert level. A high, automatically estimated alert level with either high or low confidence can certainly lead to different decisions by the human interpreter.

  9. A multi-functional converter for a reduced cost, solar powered, water pump

    Microsoft Academic Search

    David Tschanz; Howard Lovatt; Andrea Vezzini; Virginien Perrenoud

    2010-01-01

    Solar powered water pumps classically use a boost converter for power point tracking followed by a motor inverter to drive the pump. This paper introduces a new, novel solution using a Multi-Functional Converter (MFC) that combines the boost function and the motor inverter function into a single, 6-switch, inverter bridge. Thus reducing cost and complexity and increasing reliability. The paper

  10. Inverted Troughs and Their Associated Precipitation Regimes

    NSDL National Science Digital Library

    COMET

    2004-01-29

    This Webcast features Phil Schumacher, NWS Sioux Falls, South Dakota discussing the conditions that dictate the location of precipitation relative to inverted troughs. Phil presents a composite case study based on collaborative research with Dr. R. Weisman and others, as well as two examples of inverted trough events in the Central Plains. This presentation is based on his presentation at the MSC Winter Weather Course, December 2002, in Boulder, Colorado. The webcast is accompanied by a case exercise, Inverted Trough Case Exercise.

  11. Inverting ZCS Switched-Capacitor Bidirectional Converter

    Microsoft Academic Search

    Yaung-Shung Lee; Yin-Yuan Chiu; Ming-Wang Cheng

    2006-01-01

    The proposed inverting type zero-current switching switched-capacitor (ZCS SC) DC\\/DC converters are a new type of bi-directional power flow control conversion schemes. They possess high efficiency, low EMI emission and current stress features for the proposed quasi-resonant switched-capacitor inverting converters. A family of inverting type zero-current switching switched-capacitor bi-directional converters is presented, which can improve the current stress problem during

  12. Synchronverters: Inverters That Mimic Synchronous Generators

    Microsoft Academic Search

    Qing-Chang Zhong; George Weiss

    2011-01-01

    In this paper, the idea of operating an inverter to mimic a synchronous generator (SG) is motivated and developed. We call the inverters that are operated in this way synchronverters. Using synchronverters, the well-established theory\\/algorithms used to control SGs can still be used in power systems where a significant proportion of the generating capac- ity is inverter-based. We describe the

  13. Level of colorectal cancer awareness: a cross sectional exploratory study among multi-ethnic rural population in Malaysia

    PubMed Central

    2013-01-01

    Background This paper presents the level of colorectal cancer awareness among multi-ethnic rural population in Malaysia. Methods A rural-based cross sectional survey was carried out in Perak state in Peninsular Malaysia in March 2011. The survey recruited a population-representative sample using multistage sampling. Altogether 2379 participants were included in this study. Validated bowel/colorectal cancer awareness measure questionnaire was used to assess the level of colorectal cancer awareness among study population. Analysis of variance (ANOVA) was done to identify socio-demographic variance of knowledge score on warning signs and risk factors of colorectal cancer. Results Among respondents, 38% and 32% had zero knowledge score for warning signs and risk factors respectively. Mean knowledge score for warning signs and risk factors were 2.89 (SD 2.96) and 3.49 (SD 3.17) respectively. There was a significant positive correlation between the knowledge score of warning signs and level of confidence in detecting a warning sign. Socio-demographic characteristics and having cancer in family and friends play important role in level of awareness. Conclusions Level of awareness on colorectal cancer warning signs and risk factors in the rural population of Malaysia is very low. Therefore, it warrants an extensive health education campaign on colorectal cancer awareness as it is one of the commonest cancer in Malaysia. Health education campaign is urgently needed because respondents would seek medical attention sooner if they are aware of this problem. PMID:23924238

  14. Multi-level integrative analysis of Protein Protein Interaction networks: connecting completeness, depth and robustness.

    PubMed

    Blayney, Jaine K; Zheng, Huiru; Wang, Haiying; Azuaje, Francisco

    2010-01-01

    A fully extended Protein Protein Interaction (PPI) network can consist of upwards of several thousand nodes and edges. To simplify analysis, smaller child samples are often used in substitution of the global network. In this study, the impact of different levels of sampling was evaluated on six PPI networks. Results from the case studies suggest that restricting analysis to the first network level, using metrics such as degree and BC, could lead to misrepresentative results, omitting potentially significant nodes. Fault-tolerance analysis also indicates that key nodes within the second network level, and above, contribute to the stability of the global network. PMID:20693609

  15. 3D Multi-Level Non-LTE Radiative Transfer for the CO Molecule

    NASA Astrophysics Data System (ADS)

    Berkner, A.; Schweitzer, A.; Hauschildt, P. H.

    2015-01-01

    The photospheres of cool stars are both rich in molecules and an environment where the assumption of LTE can not be upheld under all circumstances. Unfortunately, detailed 3D non-LTE calculations involving molecules are hardly feasible with current computers. For this reason, we present our implementation of the super level technique, in which molecular levels are combined into super levels, to reduce the number of unknowns in the rate equations and, thus, the computational effort and memory requirements involved, and show the results of our first tests against the 1D implementation of the same method.

  16. A Multi-Level Approach to Investigating Neighborhood Effects on Physical Aggression among Urban Chicago Youth

    PubMed Central

    Maldonado-Molina, Mildred M.; Reingle, Jennifer M.; Komro, Kelli A.

    2013-01-01

    The current study evaluates neighborhood effects, individual-level effects, and demographic characteristics that influence physically aggressive behavior among urban youth. Using data derived from 5,812 adolescents from Project Northland Chicago (PNC) and Heirarchical Linear Modeling (HLM) techniques, the results suggested that neighborhood problems significantly predicted physical aggression, before and after adjustment for individual-level risk factors (alcohol use, peer alcohol use, lack of adult supervision, and depression) and demographics. After accounting for baseline physical aggression, however, neighborhood problems were no longer a significant predictor of physical aggression. Implications for intervention at both the neighborhood and individual-level and study limitations are also discussed. PMID:24049432

  17. Stress and Mental Health in Families With Different Income Levels: A Strategy to Collect Multi-Actor Data

    PubMed Central

    Wouters, Edwin

    2014-01-01

    Background Several studies have focused on family stress processes, examining the association between various sources of stress and the mental health and well-being of parents and adolescents. The majority of these studies take the individual as the unit of analysis. Multi-actor panel data make it possible to examine the dynamics of the family context over time and the differentiating effects of individual roles within the same family. Accurate information about family processes allows practitioners to provide support that enhances family resilience and minimizes the risk of mental health problems. Objective Our study contributes to the research on family stress processes by focusing on families with different income levels, and by collecting panel data from mothers, fathers, and adolescents within the same family. Methods The relationship between mothers, fathers, and children (RMFC) study is an ongoing Flemish multi-actor panel study that aims to enhance our understanding of family processes that protect the mental health and well-being of two-parent families with a target adolescent between 11 and 17 years old. Mothers, fathers, and children provide information about various aspects of family life, including finances, sources of stress, health, mental health, parenting, and coping strategies. Measures have been chosen whenever possible that have sound conceptual underpinnings and robust psychometric properties. The study posed two challenges. First, economically disadvantaged families are difficult to reach. Second, the collection of multi-actor data is often plagued by high nonresponse. To ensure that the families were targeted as successfully as possible, the study employed a purposive nonprobability sampling method. Results The RMFC study is one of the largest triadic panel studies of its kind. The first wave of quantitative data collection was conducted between February 2012 and January 2013. A total of 2566 individuals of 880 families participated in our study. The second wave of data collection will be undertaken 6-12 months later. Conclusions The strength of the RMFC study is its multi-actor panel approach of data collection among families with different income levels. Strategies that were followed to address the empirical issues involved with the sampling design are discussed, together with theoretical and practical implications. PMID:24384456

  18. Harmonics Study and Comparison of Z-source Inverter with Traditional Inverters

    Microsoft Academic Search

    B. Justus Rabi; R. Arumugam

    2005-01-01

    This paper presents an Impedance Source Inverter for A.C electrical drives. The impedance source inverter employs a unique impedance network couple with inverter main circuit and rectifier. By controlling the shoot-through duty cycle, the z-source inverter system using MOSFETS provide ride-through capability during voltage sags, reduces line harmonics, improves power factor and high reliability, and extends output voltage range. Analysis,

  19. A Class of Quasi-Z-Source Inverters

    Microsoft Academic Search

    Joel Anderson; F. Z. Peng

    2008-01-01

    In this paper, theoretical results are shown for several novel inverters. These inverters are similar to the Z- source inverters presented in previous works, but have several advantages, including in some combination; lower component ratings, reduced source stress, reduced component count and simplified control strategies. Like the Z-Source inverter, these inverters are particularly suited for applications which require a large

  20. Organizational justice and mental health: a multi-level test of justice interactions.

    PubMed

    Fischer, Ronald; Abubakar, Amina; Arasa, Josephine Nyaboke

    2014-04-01

    We examine main and interaction effects of organizational justice at the individual and the organizational levels on general health in a Kenyan sample. We theoretically differentiate between two different interaction patterns of justice effects: buffering mechanisms based on trust versus intensifying explanations of justice interactions that involve psychological contract violations. Using a two-level hierarchical linear model with responses from 427 employees in 29 organizations, only interpersonal justice at level 1 demonstrated a significant main effect. Interactions between distributive and interpersonal justice at both the individual and the collective levels were found. The intensifying hypothesis was supported: the relationship between distributive justice and mental health problems was strongest when interpersonal justice was high. This contrasts with buffering patterns described in Western samples. We argue that justice interaction patterns shift depending on the economic conditions and sociocultural characteristics of employees studied. PMID:24811881

  1. Inverting Amplifier with Current Input

    NSDL National Science Digital Library

    This animated gif illustrates the changing voltages a conventional inverting amplifier when it receives input from a current source rather than a voltage source. Notice that the input resistor does not offer any impedance. Voltages and parts of the circuit of this 3-D animated gif are highlighted with different colors. Current is displayed by green arrows indicating directional flow. The animation requires a Web browser or other video player software capable of displaying gif animations.Other 3-D Circuit Animations can be seen here.

  2. Review of PV Inverter Technology Cost and Performance Projections

    SciTech Connect

    Navigant Consulting Inc.

    2006-01-01

    The National Renewable Energy Laboratory (NREL) has a major responsibility in the implementation of the U.S. Department of Energy's (DOE's) Solar Energy Technologies Program. Sandia National Laboratories (SNL) has a major role in supporting inverter development, characterization, standards, certifications, and verifications. The Solar Energy Technologies Program recently published a Multiyear Technical Plan, which establishes a goal of reducing the Levelized Energy Cost (LEC) for photovoltaic (PV) systems to $0.06/kWh by 2020. The Multiyear Technical Plan estimates that, in order to meet the PV system goal, PV inverter prices will need to decline to $0.25-0.30 Wp by 2020. DOE determined the need to conduct a rigorous review of the PV Program's technical and economic targets, including the target set for PV inverters. NREL requested that Navigant Consulting Inc.(NCI) conduct a review of historical and projected cost and performance improvements for PV inverters, including identification of critical barriers identified and the approaches government might use to address them.

  3. Fractal multi-level organisation of human groups in a virtual world

    NASA Astrophysics Data System (ADS)

    Fuchs, Benedikt; Sornette, Didier; Thurner, Stefan

    2014-10-01

    Humans are fundamentally social. They form societies which consist of hierarchically layered nested groups of various quality, size, and structure. The anthropologic literature has classified these groups as support cliques, sympathy groups, bands, cognitive groups, tribes, linguistic groups, and so on. Anthropologic data show that, on average, each group consists of approximately three subgroups. However, a general understanding of the structural dependence of groups at different layers is largely missing. We extend these early findings to a very large high-precision large-scale internet-based social network data. We analyse the organisational structure of a complete, multi-relational, large social multiplex network of a human society consisting of about 400,000 odd players of an open-ended massive multiplayer online game for which we know all about their various group memberships at different layers. Remarkably, the online players' society exhibits the same type of structured hierarchical layers as found in hunter-gatherer societies. Our findings suggest that the hierarchical organisation of human society is deeply nested in human psychology.

  4. Kalman filter approach for estimating water level time series over inland water using multi-mission satellite altimetry

    NASA Astrophysics Data System (ADS)

    Schwatke, C.; Dettmering, D.; Bosch, W.; Seitz, F.

    2015-05-01

    Satellite altimetry has been designed for sea level monitoring over open ocean areas. However, since some years, this technology is also used for observing inland water levels of lakes and rivers. In this paper, a new approach for the estimation of inland water level time series is described. It is used for the computation of time series available through the web service "Database for Hydrological Time Series over Inland Water" (DAHITI). The method is based on a Kalman filter approach incorporating multi-mission altimeter observations and their uncertainties. As input data, cross-calibrated altimeter data from Envisat, ERS-2, Jason-1, Jason-2, Topex/Poseidon, and SARAL/AltiKa are used. The paper presents water level time series for a variety of lakes and rivers in North and South America featuring different characteristics such as shape, lake extent, river width, and data coverage. A comprehensive validation is performed by comparison with in-situ gauge data and results from external inland altimeter databases. The new approach yields RMS differences with respect to in-situ data between 4 and 38 cm for lakes and 12 and 139 cm for rivers, respectively. For most study cases, more accurate height information than from available other altimeter data bases can be achieved.

  5. Sensitivity of Aerosol Multi-Sensor Daily Data Intercomparison to the Level 3 Dataday Definition

    NASA Technical Reports Server (NTRS)

    Leptoukh, Gregory; Lary, David; Shen, Suhung; Lynnes, Christopher

    2010-01-01

    Topics include: why people use Level 3 products, why someone might go wrong with Level 3 products, differences in L3 from different sensors, Level 3 data day definition, MODIS vs. MODIS, AOD MODIS Terra vs. Aqua in Pacific, AOD Aqua MODIS vs. MISR correlation map, MODIS vs MISR on Terra, MODIS atmospheric data day definition, orbit time difference for Terra and Aqua 2009-01-06, maximum time difference for Terra (Calendar day), artifact explains, data day definitions, local time distribution, spatial (local time) data day definition, maximum time difference between Terra and Aqua, Removing the artifact in 16-day AOD correlation, MODIS cloud top pressure, and MODIS Terra and Aqua vs. AIRS cloud top pressure.

  6. Two level multi-objective reconnaissance system study of a large water resource system. Doctoral thesis

    SciTech Connect

    Chaube, U.C.

    1982-01-01

    Reconnaissance study of a large water resource system involves analysis of subsystem characteristics and subsystem interlinkages in terms of total system development objectives. Linear optimization models are developed to represent, (a) aggregate temporal and spatial characteristics of the system (b) predominant policies namely irrigation and energy development and (c) the related issues and technological options, in physical terms. A large system is viewed in terms of several constituent subsystems in which Level-I study relates to irrigation and energy development. These Level-I and Level-II studies have been carried out in the context of developmental planning of Ganga basin. The basin is characterized by predominant agriculture based economy and temporal and regional heterogeneity in the resource availability and demand pattern. The study brings out relative impact of various issues on the irrigation and energy policies in planning subregions and trade-offs which would form the basis of further creative development and detailed systems analysis.

  7. The learner’s perspective in GP teaching practices with multi-level learners: a qualitative study

    PubMed Central

    2014-01-01

    Background Medical students, junior hospital doctors on rotation and general practice (GP) registrars are undertaking their training in clinical general practices in increasing numbers in Australia. Some practices have four levels of learner. This study aimed to explore how multi-level teaching (also called vertical integration of GP education and training) is occurring in clinical general practice and the impact of such teaching on the learner. Methods A qualitative research methodology was used with face-to-face, semi-structured interviews of medical students, junior hospital doctors, GP registrars and GP teachers in eight training practices in the region that taught all levels of learners. Interviews were audio-recorded and transcribed. Qualitative analysis was conducted using thematic analysis techniques aided by the use of the software package N-Vivo 9. Primary themes were identified and categorised by the co-investigators. Results 52 interviews were completed and analysed. Themes were identified relating to both the practice learning environment and teaching methods used. A practice environment where there is a strong teaching culture, enjoyment of learning, and flexible learning methods, as well as learning spaces and organised teaching arrangements, all contribute to positive learning from a learners’ perspective. Learners identified a number of innovative teaching methods and viewed them as positive. These included multi-level learner group tutorials in the practice, being taught by a team of teachers, including GP registrars and other health professionals, and access to a supernumerary GP supervisor (also termed “GP consultant teacher”). Other teaching methods that were viewed positively were parallel consulting, informal learning and rural hospital context integrated learning. Conclusions Vertical integration of GP education and training generally impacted positively on all levels of learner. This research has provided further evidence about the learning culture, structures and teaching processes that have a positive impact on learners in the clinical general practice setting where there are multiple levels of learners. It has also identified some innovative teaching methods that will need further examination. The findings reinforce the importance of the environment for learning and learner centred approaches and will be important for training organisations developing vertically integrated practices and in their training of GP teachers. PMID:24645670

  8. Advances in series resonant inverter technology and its effect on spacecraft employing electric propulsion

    NASA Technical Reports Server (NTRS)

    Robson, R. R.

    1982-01-01

    The efficiency of transistorized Series Resonant Inverters (SRIs), which is higher than that of silicon-controlled rectifier alternatives, reduces spacecraft radiator requirements by 40% and may eliminate the need for heat pipes on 30-cm ion thruster systems. Recently developed 10- and 25-kW inverters have potential applications in gas thrusters, and represent the first spaceborne SRI designs for such power levels. Attention is given to the design and control system approaches employed in these inverter designs to improve efficiency and reduce weight, along with the impact of such improved parameters on electric propulsion systems.

  9. Assessing the effectiveness of interventions to promote advance directives among older adults: a systematic review and multi-level analysis.

    PubMed

    Bravo, Gina; Dubois, Marie-France; Wagneur, Bernard

    2008-10-01

    Many studies have investigated the effectiveness of interventions in promoting advance directives (ADs) but there is uncertainty as to what works best, and in whom. We conducted a systematic review of the evidence in this regard, using both classical meta-analysis approaches and multi-level analyses. Eleven databases were searched for relevant reports published through March 2007. All prospective studies were eligible, whether involving a single group or several and, in the latter case, regardless of the allocation mechanism. Outcomes included formal and informal ADs assessed by chart review or self-report. Heterogeneous sets of outcomes were pooled under a random-effects model. The search yielded 55 studies, half of which targeted outpatients. Most groups of subjects were educated in a single session led by one healthcare professional. Outcomes were measured within six months of the intervention in 73% of cases. The largest set of single-arm studies yielded an overall AD completion rate of 45.6%. Across randomized trials, the largest pooled odds ratio was 4.0, decreasing to 2.6 when all comparative studies were included. Multi-variable analyses identified the provision of oral information over multiple sessions as the most successful intervention. This was true regardless of the target population. These findings support the effectiveness of educational interventions in increasing the formulation of ADs and provide practical advice on how best to achieve this goal. PMID:18644667

  10. Improved estimates of upper-ocean warming and multi-decadal sea-level rise

    Microsoft Academic Search

    Catia M. Domingues; John A. Church; Neil J. White; Peter J. Gleckler; Susan E. Wijffels; Paul M. Barker; Jeff R. Dunn

    2008-01-01

    Changes in the climate system's energy budget are predominantly revealed in ocean temperatures and the associated thermal expansion contribution to sea-level rise. Climate models, however, do not reproduce the large decadal variability in globally averaged ocean heat content inferred from the sparse observational database, even when volcanic and other variable climate forcings are included. The sum of the observed contributions

  11. Accountability and Alignment under No Child Left Behind: Multi-Level Perspectives for Educational Leaders

    ERIC Educational Resources Information Center

    Choi, Daniel

    2011-01-01

    Educational leaders have faced the challenges of trying to align schoolwide reforms priorities with accountability demands under the No Child Left Behind law. This article examines the barriers that complicate meaningful alignment among federal, state and local levels. This article also offers the following recommendations: Schools and districts…

  12. Optical performance monitoring of chromatic dispersion and PMD for multi-level intensity and phase modulation

    Microsoft Academic Search

    Y. Wang; S. Hu; L.-S. Yan; A. E. Willner

    2006-01-01

    We explore monitoring techniques by simulation and experiment for 2-and 4-level, intensity-and phase-modulation data. DOP for PMD up to 200-ps and clock-tone for dispersion up to 1500-ps are examined for 10-Gsymbol\\/s RZ and NRZ systems.

  13. Fuzzy Model-Based Predictive Control applied to multivariable level control of multi tank system

    Microsoft Academic Search

    Sevil Ahmed; Michail Petrov; Alexandar Ichtev

    2010-01-01

    In this study issues related to applicability of Model-Based Predictive Control (MBPC) to nonlinear and complex processes are addressed. A tank system is taken as an exemplary process, and its prediction model is used for control purposes. Obtained results are applied for level control of a tank process. A Takagi-Sugeno type fuzzy neural network is used to model the nonlinear

  14. Multi-Level Coding Efficiency with Improved Quality for Image Compression based on AMBTC

    E-print Network

    Somasundaram, Dr K

    2012-01-01

    In this paper, we have proposed an extended version of Absolute Moment Block Truncation Coding (AMBTC) to compress images. Generally the elements of a bitplane used in the variants of Block Truncation Coding (BTC) are of size 1 bit. But it has been extended to two bits in the proposed method. Number of statistical moments preserved to reconstruct the compressed has also been raised from 2 to 4. Hence, the quality of the reconstructed images has been improved significantly from 33.62 to 38.12 with the increase in bpp by 1. The increased bpp (3) is further reduced to 1.75in multiple levels: in one level, by dropping 4 elements of the bitplane in such a away that the pixel values of the dropped elements can easily be interpolated with out much of loss in the quality, in level two, eight elements are dropped and reconstructed later and in level three, the size of the statistical moments is reduced. The experiments were carried over standard images of varying intensities. In all the cases, the proposed method outp...

  15. Elements of a multi-level theory of presence: Phenomenology, mental processing and neural correlates

    Microsoft Academic Search

    Wijnand IJsselsteijn

    2002-01-01

    Summary Presence research is still at an early stage of development, and theoretical contributions are needed that integrate diverse insights relevant to understanding presence, emerging from different contributing areas. In this paper, we outline what we regard to be key elements of a theory of presence, addressing the experience at three distinct levels of explanation: phenomenology, mental processing, and underlying

  16. Semi-Supervised Abstraction-Augmented String Kernel for Multi-Level Bio-Relation Extraction

    E-print Network

    Collobert, Ronan

    -expressed in transduced cells with three separate AAV vectors. Positive This study demonstrates that IL - 8 recognizes is important in biomedical domains, since most scientific discoveries describe biological relationships between levels of detail in the text [14]. Specifically we cover three tasks in our experiments associated

  17. Temporal and spectral investigation of multi-Landau level quantum beats in GaAs

    SciTech Connect

    Siegner, U.; Mycek, M.A.; Chemla, D.S.

    1994-05-01

    By resolving temporally and spectrally transient four-wave-mixing, the authors observe multiple Landau level quantum beating in GaAs under 6T magnetic field. Excitation energy and density dependent quantum interference gives rise to non-periodic beats.

  18. Transforming Loops to Recursion for Multi-Level Memory Hierarchies * Rice University

    E-print Network

    California at Berkeley, University of

    , recursive (e.g., divide-and-conquer) al- gorithms appear to have some potentially valuable locality *This347884, and supported in part by DARPA and Rome Laboratory, Air Force Ma- teriel Command, USAF, under that is simultaneously blocked at many different levels, in effect providing a hierarchy of working sets. Many other and-conquer

  19. Water in the Middle East, a Secondary and College Level Multi-Media Study.

    ERIC Educational Resources Information Center

    Manneberg, Eliezer

    The secondary and college level guide outlines a course of study on the Middle East, with emphasis on water problems of the area. Among the course objectives are the following: (1) make generalizations about particular Middle Eastern cultures and support them with evidence; (2) interpret environmental and social data from specific Middle Eastern…

  20. The Effect of Pixel-Level Fusion on Object Tracking in MultiSensor Surveillance Video

    Microsoft Academic Search

    Nedeljko Cvejic; Stavri G. Nikolov; Henry D. Knowles; Artur Loza; Alin Achim; David R. Bull; Cedric Nishan Canagarajah

    2007-01-01

    This paper investigates the impact of pixel-level fusion of videos from visible (VIZ) and infrared (IR) surveillance cameras on object tracking performance, as compared to tracking in single modality videos. Tracking has been ac- complished by means of a particle filter which fuses a colour cue and the structural similarity measure (SSIM). The highest tracking accuracy has been obtained in