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1

MULTILEVEL INVERTER, BASED ON MULTI-STAGE CONNECTION OF THREE-LEVEL CONVERTERS, SCALED IN POWER OF THREE.  

E-print Network

MULTILEVEL INVERTER, BASED ON MULTI-STAGE CONNECTION OF THREE-LEVEL CONVERTERS, SCALED IN POWER. #12;MULTILEVEL INVERTER, BASED ON MULTI-STAGE CONNECTION OF THREE-LEVEL CONVERTERS, SCALED IN POWER, which give flexibility to the system. #12;MULTILEVEL INVERTER, BASED ON MULTI-STAGE CONNECTION OF THREE

Catholic University of Chile (Universidad Católica de Chile)

2

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

E-print Network

HIGH-LEVEL MULTI-STEP INVERTER OPTIMIZATION, USING A MINIMUM NUMBER OF POWER TRANSISTORS. Juan supplies and semiconductors (transistors or GTOs) for a given number of levels. Different combinations levels of voltage with only four power supplies and sixteen transistors per phase are shown. #12;2 I

Catholic University of Chile (Universidad Católica de Chile)

3

Control of a hybrid asymmetric multi-level inverter for competitive medium-voltage industrial drives  

Microsoft Academic Search

Hybrid asymmetric multi-level inverters promise significant improvements for medium-voltage industrial drives. Floating sub inverters without feeding can only supply reactive power. An on-line nonlinear model-predictive controller stabilizes their intermediate-circuit voltages in steady-state and during transients, as demonstrated by simulations and measurements. A pre-charge method assures converter start-up without additional equipment.

Martin Veenstra; Alfred Rufer

2003-01-01

4

A single-phase multi-level D-STATCOM inverter using modular multi-level converter (MMC) topology for renewable energy sources  

NASA Astrophysics Data System (ADS)

This dissertation presents the design of a novel multi-level inverter with FACTS capability for small to mid-size (10-20kW) permanent-magnet wind installations using modular multi-level converter (MMC) topology. The aim of the work is to design a new type of inverter with D-STATCOM option to provide utilities with more control on active and reactive power transfer of distribution lines. The inverter is placed between the renewable energy source, specifically a wind turbine, and the distribution grid in order to fix the power factor of the grid at a target value, regardless of wind speed, by regulating active and reactive power required by the grid. The inverter is capable of controlling active and reactive power by controlling the phase angle and modulation index, respectively. The unique contribution of the proposed work is to combine the two concepts of inverter and D-STATCOM using a novel voltage source converter (VSC) multi-level topology in a single unit without additional cost. Simulations of the proposed inverter, with 5 and 11 levels, have been conducted in MATLAB/Simulink for two systems including 20 kW/kVAR and 250 W/VAR. To validate the simulation results, a scaled version (250 kW/kVAR) of the proposed inverter with 5 and 11 levels has been built and tested in the laboratory. Experimental results show that the reduced-scale 5- and 11-level inverter is able to fix PF of the grid as well as being compatible with IEEE standards. Furthermore, total cost of the prototype models, which is one of the major objectives of this research, is comparable with market prices.

Sotoodeh, Pedram

5

Single phase multi-level PWM Inverter topologies using coupled inductors  

Microsoft Academic Search

The number of voltage levels available in PWM voltage source inverters can be increased by using a split-wound coupled inductor within each inverter-leg and using interleaved PWM switching of the upper and lower switches. The magnetizing inductance of the symmetrical split wound inductor filter the high frequency PWM voltage differences between the upper and lower switches. The same inductor presents

J. Salmon; A. Knight; J. Ewanchuk

2008-01-01

6

A diode-clamped multi-level inverter for the StatCom\\/BESS  

Microsoft Academic Search

Flexible AC transmission systems (FACTS) are potentially becoming more flexible and more economical local controllers in the power system. The integration of traditional FACTS devices with energy storage system (ESS) will increase FACTS device functionality. The voltage-sourced inverter is an important part of many FACTS devices, such as the StatCom and SSSC. Considerable research has been done on 2-level inverter

Ying Cheng; Mariesa L. Crow

2002-01-01

7

Multilevel inverter, based on multi-stage connection of three-level converters scaled in power of three  

Microsoft Academic Search

A multi-stage inverter using three-state converters is being analyzed for multipurpose applications, such as active power filters, static VAr compensators and machine drives for sinusoidal and trapezoidal current applications. The great advantage of this kind of converter is the minimum harmonic distortion obtained. The drawbacks are the isolated power supplies required for each one of the stages of the multiconverter.

Juan Dixon; Luis Moran

2002-01-01

8

Development of multi step current source inverter  

NASA Astrophysics Data System (ADS)

Static power converter apparatus has been generally propagated with the rapid development of power semiconductor devices. Especially, CVCF and VVVF inverter have been used for induction motor drives and computer system operation without stoppage of power supply. But these inverters generate the harmonic currents and voltages. In this case the generated harmonics originate such obstacles as the burning of condenser for improving power factor, the rupture of neutral line, the torque ripple of motor in power distribution system and load equipment. The multi step method has been studied in order to suppress the harmonic obstacles of the inverter. But this method has faults such as the increment of the number of inverter and the need of phase shifting transformer (Zig-Zag, Fork connection) in order to increase above 12 steps. Therefore it is important that inverter apparatus are simple compared with the conventional one and its the effect of harmonic reduction is equal to the conventional one. Until now we have studied the multi tap changing converter for reducing the harmonics. So in this study, by using the technique of harmonic reduction in converter apparatus, we are going to develop the multi step current source inverter for reducing economically the harmonics involved in current output.

Chul-Ro, Yu

9

Multi-level converters for three-phase photovoltaic applications  

E-print Network

of PV panels distributed in a matrix. The principle is similar to methods used in multi-level inverters. INTRODUCTION Fig. 1. Multi-level inverter for single-phase grid connected PV modules [1] Multi-level inverters-LEVEL INVERTER FOR SINGLE-PHASE GRID CONNECTED PV MODULES [1] Va S1 S2 S3 S4 S5 S6 Sa1 Sa2 Sa3 Sa4 Sa5 Sa6 V7

Lehman, Brad

10

Reduced Switch Count Multi-Level Inverter Structures With Common Mode Voltage Elimination And DC-Link Capacitor Voltage Balancing For IM Drives.  

E-print Network

??Multilevel inverter technology has emerged recently as a very important alternative in the area of high-power medium-voltage energy control. Voltage operation above semiconductor device limits, (more)

Mondal, Gopal

2008-01-01

11

Performance analysis on a multi-type inverter air conditioner  

Microsoft Academic Search

An analysis was conducted for a multi-type inverter air conditioner with a linear electronic valve as the expansion device and a variable speed compressor. The system performance was analyzed with variations of operating frequency of the compressor, cooling load imposed on the system and cooling load fraction (i.e. load ratio) between rooms in which is installed an evaporator. The optimum

Youn Cheol Park; Young Chul Kim; Man-Ki Min

2001-01-01

12

Mono inverter Multi parallel PMSM -Structure and Control strategy  

E-print Network

a new and original Mono inverter Multi parallel Permanent Magnet Synchronous Motor (PMSM) system. To obtain the stability of such a system, each of the motor synchronisms should always be respected regardless of their load torque. In this case, only one motor, called "master motor", will be self

Boyer, Edmond

13

A four level rectifier-inverter system for drive applications  

Microsoft Academic Search

Multilevel converter technology has been receiving increased attention, especially for high power applications. In particular, three level drive systems have been extensively reported. In this paper, a four level rectifier-inverter system is investigated for drive applications. A dynamic control algorithm is described which balances the voltages on a 4 level rectifier-inverter drive system primarily from the rectifier. The proposed control

Gautam Sinha; T.A. Lipo

1996-01-01

14

A four level rectifier inverter system for drive applications  

Microsoft Academic Search

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

G. Sinha; T.A. Lipo

1998-01-01

15

Capacity modulation of an inverter-driven multi-air conditioner using electronic expansion valves  

Microsoft Academic Search

An inverter-driven multi-air conditioner provides the benefits of comfort, energy conservation and easy maintenance. Recently, the multi-air conditioner has been employed in small and medium-sized buildings. However, the performance data and control algorithm for multi-air conditioners are limited in literature due to complicated system parameters and operating conditions. In the present study, the performance of an inverter-driven multi-air conditioner having

J. M Choi; Y. C Kim

2003-01-01

16

Five-level GTO inverters for large induction motor drives  

Microsoft Academic Search

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

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

1994-01-01

17

A Space Vector PWM Scheme for Multilevel Inverters Based on Two-Level Space Vector PWM  

Microsoft Academic Search

Multilevel inverters are increasingly being used in high-power medium voltage applications due to their superior performance compared to two-level inverters. Among various modulation techniques for a multilevel inverter, the space vector pulsewidth modulation (SVPWM) is widely used. However, the implementation of the SVPWM for a multilevel inverter is complicated. The complexity is due to the difficulty in determining the location

Amit Kumar Gupta; Ashwin M. Khambadkone

2006-01-01

18

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

E-print Network

A Five-Level Three-Phase Hybrid Cascade Multilevel Inverter Using a Single DC Source for a PM to construct a 3-phase 5-level cascade multilevel inverter to be used as a drive for a PM traction motor. The 5% higher than that obtained using a standard 3-leg inverter by itself. Index Terms-- Multilevel Converter

Tolbert, Leon M.

19

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

Microsoft Academic Search

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

Poh Chiang Loh; Feng Gao; Frede Blaabjerg

2008-01-01

20

A single phase multi-string PV inverter with minimal bus capacitance  

Microsoft Academic Search

The multi-string photovoltaic (PV) inverter is of interest for building grid-connected PV systems because it offers a number of advantages compared to conventional centralized or single-stage inverters. Optimal operation of the system can be achieved since the maximum power point (MPP) of each string is controlled by a local dc-dc converter input stage. The input dc-dc converter also provides voltage

J. Schonberger

2009-01-01

21

Development of New Three-Level Current-Source Inverter for Grid Connected Photovoltaic System  

E-print Network

, and innovative inverter solutions. Multilevel CSI has been proposed in [3], but this converter needs two large the switches. Reference [4] reported the multilevel CSI driven by single gate power supply in an inverter sideDevelopment of New Three-Level Current-Source Inverter for Grid Connected Photovoltaic System

Fujimoto, Hiroshi

22

A 7-Level Single DC Source Cascaded H-Bridge Multilevel Inverters Control  

E-print Network

A 7-Level Single DC Source Cascaded H-Bridge Multilevel Inverters Control Using Hybrid Modulation F a new hybrid cascaded H- bridge multilevel inverter (HCMLI) motor drive DTC control scheme for electric efficient torque and flux controller is obtained, enabling a DTC solution for hybrid multilevel inverter

Paris-Sud XI, Université de

23

Current control of a 3-level rectifier\\/inverter drive system  

Microsoft Academic Search

The marriage of a three-level voltage source inverter with a force-commutated three-level rectifier is examined in this paper. Three-level inverters are capable of reducing the output current harmonics dramatically compared with typical two-level inverters whereas a three-level rectifier of this type allows nearly sinusoidal input currents at unity fundamental power factor on the utility side of the drive system. The

Michael C. Klabunde; Yifan Zhao; T.A. Lipo

1994-01-01

24

Analysis of different topologies of multilevel inverters.  

E-print Network

??This thesis compares three different topologies of inverters (one level inverter, Diode clamped inverter, Flying capacitor clamped inverter and Cascaded H-bridge inverter). The multilevel inverters (more)

Mohammadreza, Derakhshanfar

2010-01-01

25

Multi-tracking single-fed PV inverter  

Microsoft Academic Search

Grid-connected photovoltaic system is the most important among the photovoltaic applications. High efficiency power converter and maximum power point tracking (MPPT) are the key technologies of grid-connected inverters for photovoltaic system. Shadows created by clouds, trees ...etc. partially cover PV modules causes illumination decrease, in this condition the Current-voltage and power-voltage characteristics of large photovoltaic (PV) arrays become more complex

Ahmad Al-Diab; Constantinos Sourkounis

2010-01-01

26

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

Microsoft Academic Search

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

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

2009-01-01

27

A Seven-Level Inverter Topology for Induction Motor Drive Using Two-Level Inverters and Floating Capacitor Fed H-Bridges  

Microsoft Academic Search

A multilevel inverter topology for seven-level space vector generation is proposed in this paper. In this topology, the seven-level structure is realized using two conventional two-level inverters and six capacitor-fed H-bridge cells. It needs only two isolated dc-voltage sources of voltage rating V dc \\/2 where V dc is the dc voltage magnitude required by the conventional neutral point clamped

P. P. Rajeevan; K. Sivakumar; Chintan Patel; Rijil Ramchand; K. Gopakumar

2011-01-01

28

Some Improvements in 81-Level Inverters for Traction Drive Juan Dixon, Cristin Elgueta and Luis Morn  

E-print Network

Some Improvements in 81-Level Inverters for Traction Drive Systems Juan Dixon, Cristián Elgueta and Luis Morán Abstract The application of high-level multilevel converters in traction systems is very. If the number of levels is high enough, the inverter can also operate in Amplitude Modulation (AM) mode

Catholic University of Chile (Universidad Católica de Chile)

29

Investigation on the clamping voltage self-balancing of the three-level capacitor clamping inverter  

Microsoft Academic Search

This paper deals with the self-balancing quality of the clamping voltage in the three-level capacitor clamping inverter due to the spontaneous clamping capacitor current control loop in the circuit. Self-balancing quality of the three-level capacitor clamping inverter under sub-harmonic PWM modulation is analyzed in detail. The self-balancing mechanism in the multilevel capacitor clamping inverter (M>3) under sub-harmonic PWM modulation is

Xiaoming Yuan; Herbert Stemmler; I. Barbi

1999-01-01

30

Development and testing of a multi-type air conditioner without using AC inverters  

Microsoft Academic Search

This paper reports the results from the development and performance testing of a cost effective, energy efficient, multi-type air conditioner that connected five indoor units (evaporators) to one outdoor unit (condenser) with a digital scroll compressor. Instead of using inverter technology, which has a potential risk of harmonic current emissions, this study used a digital scroll compressor, which provided the

Shih-Cheng Hu; Rong-Hwa Yang

2004-01-01

31

Development and testing of a multi-type air conditioner without using AC inverters  

Microsoft Academic Search

This paper reports the results from the development and performance testing of a cost effective, energy efficient, multi-type air conditioner that connected five indoor units (evaporators) to one outdoor unit (condenser) with a digital scroll compressor. Instead of using inverter technology, which has a potential risk of harmonic current emissions, this study used a digital scroll compressor, which provided the

Shih-Cheng Hu; Rong-Hwa Yang

2005-01-01

32

Adaptive control for a multi-condenser inverter heat pump system  

Microsoft Academic Search

A constant-speed heat pump is unsuitable for a multi-condenser system, owing to the impossibility of using the same compressor frequency to control individual subsystems. In the present study therefore, an inverter heat pump actuated by a variable-speed compressor was adapted for a multi-condenser system. To control the temperature of two air-conditioned rooms individually, two step-motor-driven electronic expansion valves (EEVs) were

Qilun Song; Gi-Yong Hong; Keum-Shik Hong

2010-01-01

33

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

Microsoft Academic Search

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

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

2007-01-01

34

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

Microsoft Academic Search

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

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

2006-01-01

35

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

Microsoft Academic Search

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

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

2007-01-01

36

Parametric Design of Five-Level Active NPC Inverter  

NASA Astrophysics Data System (ADS)

This paper describes the loss analysis and capacitor designing method for an active neutral-point-clamped (ANPC) multilevel inverter. The ANPC circuit topology is a combination of a neutral-point-clamp circuit and flying capacitor circuit topologies. This circuit requires lesser number of components than conventional multilevel converters. Loss analysis is performed using mathematical expressions. The analysis results of the losses agreed with the experimental results.

Kashihara, Yugo; Itoh, Jun-Ichi

37

A five-level inverter topology with common-mode voltage elimination for induction motor drives  

Microsoft Academic Search

Common-mode voltages generated by PWM inverters in induction motor drives cause shaft voltages, bearing currents and ground leakage currents resulting into early mechanical failure of machine bearings and conducted EMI. A five-level inverter topology with switching state combination selection strategy for the PWM control is proposed for an open-end winding induction motor drive, which completely eliminates the common-mode voltages at

P. N. Tekwani; R. S. Kanchan; K. Gopakumar; A. Vezzini

2005-01-01

38

Direct power control of grid connected PV systems with three level NPC inverter  

SciTech Connect

This paper presents the control of a three-level Neutral Point Clamped (NPC) voltage source inverter for grid connected photovoltaic (PV) systems. The control method used is the Extended Direct Power Control (EDPC), which is a generic approach for Direct Power Control (DPC) of multilevel inverters based on geometrical considerations. Maximum Power Point Tracking (MPPT) algorithms, that allow maximal power conversion into the grid, have been included. These methods are capable of extracting maximum power from each of the independent PV arrays connected to each DC link voltage level. The first one is a conventional MPPT which outputs DC link voltage references to EDPC. The second one is based on DPC concept. This new MPPT outputs power increment references to EDPC, thus avoiding the use of a DC link voltage regulator. The whole control system has been tested on a three-level NPC voltage source inverter connected to the grid and results confirm the validity of the method. (author)

Alonso-Martinez, Jaime; Eloy-Garcia, Joaquin; Arnaltes, Santiago [Dept. of Electrical Engineering, University Carlos III of Madrid, Avda. Universidad 30, 28911 Leganes, Madrid (Spain)

2010-07-15

39

Applications of cascade multilevel inverters.  

PubMed

Cascade multilevel inverters have been developed for electric utility applications. A cascade M-level inverter consists of (M-1)/2 H-bridges in which each bridge's dc voltage is supported by its own dc capacitor. The new inverter can: (1) generate almost sinusoidal waveform voltage while only switching one time per fundamental cycle; (2) dispense with multi-pulse inverters' transformers used in conventional utility interfaces and static var compensators; (3) enables direct parallel or series transformer-less connection to medium- and high-voltage power systems. In short, the cascade inverter is much more efficient and suitable for utility applications than traditional multi-pulse and pulse width modulation (PWM) inverters. The authors have experimentally demonstrated the superiority of the new inverter for power supply, (hybrid) electric vehicle (EV) motor drive, reactive power (var) and harmonic compensation. This paper summarizes the 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 demonstrated the superiority of the new inverters. PMID:14566981

Peng, Fang-zen; Qian, Zhao-ming

2003-01-01

40

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

Microsoft Academic Search

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 \\

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

2007-01-01

41

New DTC control scheme for the induction motor fed with a three-level inverter  

Microsoft Academic Search

In this paper a new scheme based on direct torque control strategy is presented. The new controller is used to control an induction motor fed with a three-level inverter. The new control scheme avoids the use of the classical hysteresis block and the look-up table. Instead, the torque and stator flux errors are used together with the motor speed to

X. del Toro; M. G. Jayne; P. A. Witting; V. M. Sala; A. Arias; J. L. Romeral

2005-01-01

42

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

SciTech Connect

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.

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

2009-01-01

43

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

E-print Network

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 ...

Schrock, Kenneth C

2008-01-01

44

Multi-level modulation codes and multi-stage decoding  

NASA Technical Reports Server (NTRS)

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.

Lin, Shu

1990-01-01

45

Interfacing Renewable Energy Sources to the Utility Grid Using a Three-Level Inverter  

Microsoft Academic Search

This paper presents a novel approach for the connection of renewable energy sources to the utility grid. Due to the increasing power capability of the available generation systems, a three-level three-phase neutral-point-clamped voltage-source inverter is selected as the heart of the interfacing system. A multivariable control law is used for the regulator because of the intrinsic multivariable structure of the

Salvador Alepuz; Sergio Busquets-Monge; Josep Bordonau; Javier Gago; David Gonzlez; Josep Balcells

2006-01-01

46

A circuit design for clamping an overvoltage in three-level GTO inverters  

Microsoft Academic Search

Three-level GTO inverters seem to be best suited for high power and high voltage AC applications. The circuit design of GTO power conversion systems is determined by the snubber circuits, which are necessary to release the GTOs from turn-on and turn-off switching losses and to keep the overvoltages to be caused by GTO switching low. However, the overvoltage snubber for

Bum-Seok Suh; Dong-Seok Hyun; Hong-Kyu Choi

1994-01-01

47

Zero-voltage switching for three-level capacitor clamping inverter  

Microsoft Academic Search

A zero-voltage switching (ZVS) scheme for a three-level capacitor clamping inverter based on the true pulsewidth modulation (PWM) pole is proposed in this paper. With this scheme, the main switches work with ZVS through the assistance of a small rating zero current switching (ZCS) lossless auxiliary circuitry without imposing any voltage\\/current spikes on the main devices or any extra control

Xiaoming Yuan; Ivo Barbi

1999-01-01

48

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

Microsoft Academic Search

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

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

2009-01-01

49

A power electronic transformer (PET) fed nine-level H-bridge inverter for large induction motor drives  

Microsoft Academic Search

This paper is devoted to the investigation of a 500 HP induction machine drive based on a nine-level 4.16 kV H-bridge inverter. Previous work in the area of controlling H-bridge inverters at such power levels report enhancement in the performance of a conventional staircase modulation technique by employing optimization of switching angles to minimize voltage distortion. However, the DC link

R. Kieferndorf; Giri Venkataramanan; Madhav D. Manjrekar

2000-01-01

50

Three-level inverter based active power filter for the three-phase, four-wire system  

Microsoft Academic Search

In this paper, the three-phase four-wire active power filter based on a three-level neutral-point-clamped inverter is presented. The proposed active power filter and controller eliminate harmonics in all three phases as well as the neutral current. The existing neutral-point-clamped inverter for a three-phase three-wire system is used for the three-phase four-wire system since the split DC capacitors provide a neutral

Oleg Vodyakho; Taehyung Kim; Sangshin Kwak

2008-01-01

51

A five\\/nine-level twelve-switch neutral point clamped inverter for high speed electric drives  

Microsoft Academic Search

A twelve-switch, three phase, five\\/nine level inverter is presented for applications using a high speed electric machine with a relatively low per-unit leakage reactance. By reducing the voltage blocking requirement of the semiconductors, the neutral point clamped variant of the coupled inductor inverter topology (NPC-CI) is more suited to high DC bus voltages, and features a significant reduction in magnetic

Jeffrey Ewanchuk; John Salmon; Behzad Vafakhah

2010-01-01

52

Hybrid Pwm Switching Strategy for a Three-Level Inverter Fed Induction Motor Drive with Open-End Windings  

NASA Astrophysics Data System (ADS)

A dual two-level inverter fed induction motor with open-end windings is capable of generating a three-level output voltage. Several, sine-triangle and space vector pulse width modulation (PWM) switching strategies are presented for the dual-inverter scheme either using space-vector or carrier-based implementation. In this paper, a hybrid PWM switching strategy for the dual-inverter scheme is proposed employing sine-triangle PWM (SPWM) and space vector PWM (SVPWM) for the individual inverters. SPWM is theoretically analyzed and space vector based implementation of SPWM is presented using a simple offset-time concept. This is exploited to implement the hybrid PWM switching strategy for the dual two-level inverter. The implementation of the hybrid PWM switching strategy proposed in this paper do not require any look-up tables, the switching is totally automatic obviating the time-consuming task of sector identification. The implementation of the hybrid PWM scheme requires only the three instantaneous phase reference voltages corresponding to the reference space vector. The third harmonic component in the voltage appearing across the motor phase windings in the induction motor is significantly reduced (by 50%) with the use of the proposed hybrid PWM scheme as compared to the use of the PWM scheme presented earlier. Also, the percentage weighted total harmonic distortion (%WTHD) of the output voltage is significantly reduced in the entire range of speed of the induction motor driven by the dual-inverter scheme.

Srinivas, S.; Ramachandrasekhar, K.

2010-06-01

53

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

E-print Network

Conditions for Capacitor Voltage Regulation in a Five-Level Cascade Multilevel Inverter Abstract-- A cascade multilevel inverter is a power electronic device built to synthesize a desired AC a cascade multilevel inverter can be used to obtain a voltage boost at higher speeds for a three-phase PM

Tolbert, Leon M.

54

Virtual-Flux Direct Power Control for Mains Connected Three-Level NPC Inverter Systems  

NASA Astrophysics Data System (ADS)

This paper proposes a control strategy which extends the Virtual-Flux Direct Power Control traditionally employed for the conventional two-level VSI to a three-level NPC inverter. This topology generates a higher number of output voltage levels, increasing the flexibility for selecting an appropriate voltage vector. The mid-point potential is controlled according to the direction of the mid-point current and the sign of the mid-point voltage deviation. The method is adapted to be used with an LCL output filter, where some undesirable characteristics, such as filter resonance, have to be compensated. Further investigation concerning the dependency of the mid-point voltage with the current phase-shift is given. Theoretical analysis is presented and the performance of the proposed method is verified by simulation.

Serpa, Leonardo A.; Kolar, Johann W.

55

Modelling and control of a seven level NPC voltage source inverter. Application to high power induction machine drive  

NASA Astrophysics Data System (ADS)

In this paper, we study a new kind of continuous-alternating converters: a seven-level neutral point clamping (NPC) voltage source inverter (VSI). We propose this inverter for applications in high voltage and high power fields. In the first part, we develop the knowledge and the control models of this inverter using the connections functions of the semi-conductors. After that, we present two pulse width modulation (PWM) algorithms to control this converter using its control model. We propose these algorithms for digital implementation. This multilevel inverter is associated to the induction machine. The performances obtained are full of promise to use it in the high voltage and high power fields of electrical traction.

Gheraia, H.; Berkouk, E. M.; Manesse, G.

2001-08-01

56

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

SciTech Connect

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.

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

2007-01-01

57

Electromagnetically induced transparency in an inverted Y-type four-level system  

NASA Astrophysics Data System (ADS)

The interaction of a weak probe laser with an inverted Y-type four-level atomic system driven by two additional coherent fields is investigated theoretically. Under the influence of the coherent coupling fields, the steady-state linear susceptibility of the probe laser shows that the system can have single or double electromagnetically induced transparency windows depending on the amplitude and the detuning of the coupling lasers. The corresponding index of refraction associated with the group velocity of the probe laser can be controlled at both transparency windows by the coupling fields. The propagation of the probe field can be switched from superluminal near the resonance to subluminal on resonance within the single transparency window when two coupling lasers are on resonance. We propose an atomic 87Rb system for experimental observation.

Qi, Jianbing

2010-01-01

58

Control of cascaded multilevel inverters  

Microsoft Academic Search

A new type of multilevel inverter is introduced which is created by cascading two three-phase three-level inverters using the load connection, but requires only one dc voltage source. This new inverter can operate as a seven-level inverter and naturally splits the power conversion into a higher-voltage lower-frequency inverter and a lower-voltage higher-frequency inverter. This type of system presents particular advantages

Keith A. Corzine; Mike W. Wielebski; Fang Z. Peng; Jin Wang

2004-01-01

59

Multi-Level Chat Server The Multi-Level Chat (ML Chat) server supports  

E-print Network

client/server was developed in and implemented in a joint task force exercise. No client softwareMulti-Level Chat Server Background The Multi-Level Chat (ML Chat) server supports near real time undertaking the development of the ML Chat Server. The most important requirements were: · Operation in low

60

Comparison of Cascaded H-Bridge, Neutral Point Clamped and Flying Capacitor multilevel inverters using multicarrier PWM  

Microsoft Academic Search

Multilevel Inverters are becoming popular for their high voltage operating capability for high power applications. This paper presents a comparative study of Cascaded H-Bridge, Neutral Point Clamped and Flying Capacitor multilevel voltage source inverters. These five-level inverters are simulated in MATLAB\\/ Simulink using multi carrier sine pulse width modulation. FFT analyses of output voltages for an RL load is carried

T. Porselvi; Ranganath Muthu

2011-01-01

61

Analysis of an inverter-supplied multi-winding transformer with a full-wave rectifier at the output  

NASA Astrophysics Data System (ADS)

This paper deals with the magnetic analysis of an inverter-supplied multi-winding transformer frequently used in resistance spot welding applications. The basic structure of the analyzed system consists of an inverter, a single-phase transformer with two secondary windings and a full-wave rectifier mounted at the output of the transformer, which assure a very short rise time of the welding current. The disturbing current spikes often appear in the transformer's primary in the steady-state operation, which can activate the over-current protection switch-off of the system. The results of numerical analysis performed on the nonlinear model of the discussed system have shown that very strong magnetic saturation of the transformer's iron core, caused by the interaction among the different ohmic resistances of secondary windings and different characteristics of the output rectifier diodes, provokes unwanted current spikes. Magnetic saturation could be efficiently eliminated using very simple passive method proposed in this paper. All findings are confirmed by systematic analysis numerically and experimentally.

Klop?i?, Beno; Dolinar, Drago; tumberger, Gorazd

62

Analysis, control and applications of neutral point clamped PWM inverters  

E-print Network

Inverters is required. V(dc) /2 S SO V (dc) S2 V (out) Figure 1. Schematic of' three level Inverter (c) (d) Figure 2. Comparison of two state and three state Inverter waveforms (a) Three state Inverter, phase control (b) Conventional Inverter..., phase control (c) Three state Inverter, PWM control (d) Conventional Inverter, PWM control ? V? Inverter I o/p Inverter 2 Figure 3. Conventional three state Inverter The Depenbrock Inverter (Fig. 4) has been the preferred topology for liigh...

Jakkli, Ranjit V

2012-06-07

63

Multilevel cascade voltage source inverter with separate DC sources  

DOEpatents

A multilevel cascade voltage source inverter having separate DC sources is described herein. This inverter is applicable to high voltage, high power applications such as flexible AC transmission systems (FACTS) including static VAR generation (SVG), power line conditioning, series compensation, phase shifting and voltage balancing and fuel cell and photovoltaic utility interface systems. The M-level inverter consists of at least one phase wherein each phase has a plurality of full bridge inverters equipped with an independent DC source. This inverter develops a near sinusoidal approximation voltage waveform with only one switching per cycle as the number of levels, M, is increased. The inverter may have either single-phase or multi-phase embodiments connected in either wye or delta configurations. 15 figs.

Peng, F.Z.; Lai, J.S.

1997-06-24

64

Neutral-Point Potential Balancing of Three-Level Inverters in Direct-Driven Wind Energy Conversion System  

Microsoft Academic Search

With the increase of wind energy conversion system (WECS) capacity, conventional two-level voltage source convert- ers tend to be replaced gradually by multilevel neutral-point (NP)- clamped converters. In this study, the topology of a boost three- level (TL) chopper on the front of a TL diode-clamped inverter is used for direct-driven WECSs. The switch-signal phase delay control (SSPDC) is proposed

Changliang Xia; Xin Gu; Tingna Shi; Yan Yan

2011-01-01

65

Pixel-level image fusion based on multi-to-multi turbo iterative  

Microsoft Academic Search

A pixel-level image fusion method based on multi-to-multi turbo iterative is proposed. An innovative multi-to-multi image fusion idea is introduced in this paper. Undoubtedly, it's impossible to cover all the information contained in several images by one image. So multi-to-multi image fusion system is much more reasonable than multi-to-one image fusion system. Based on this idea, getting several orthogonal images

Na Li; Chu He; Lei Yu; Hong Sun

2007-01-01

66

Control Scheme of Three-Level NPC Inverter for Integration of Renewable Energy Resources Into AC Grid  

Microsoft Academic Search

This paper presents a multiobjective control scheme based on the dynamic model of three-level, neutral-point-clamped voltage source inverter for integration of distributed generation (DG) resources based on renewable energy resources to the distribution grid. The proposed model has been derived from the abc\\/${\\\\alpha\\\\beta}$ and ${\\\\alpha\\\\beta}$\\/dq transformation of the AC system variables. The proposed control technique generates the compensation current references

Edris Pouresmaeil; Daniel Montesinos-Miracle; Oriol Gomis-Bellmunt

2012-01-01

67

Multi-Level TESLA: Broadcast Authentication for Distributed Sensor Networks  

E-print Network

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

Ning, Peng

68

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

E-print Network

, and multilevel inverter. I. INTRODUCTION The problem of eliminating harmonics in switching inverters has been the focus of research for many years. The current trend of modulation control for multilevel inverters methods are not the best solution for multilevel inverter control due to their high switching frequency

Tolbert, Leon M.

69

Electronic multi-purpose material level sensor  

DOEpatents

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.

McEwan, Thomas E. (Livermore, CA)

1997-01-01

70

23Level Inverter for Electric Vehicles Using a Single Battery Pack and Series Active Filters  

Microsoft Academic Search

Cascaded H-bridge (CHB) multilevel inverters have been conceived as an alternative to reduce total harmonic distortion (THD) in medium-voltage drives. The reduced THD makes them useful for electric vehicle (EV) applications, but the main problem with the CHB is the large amount of isolated power sources required to feed each of the H-bridges. An improved variant known as the asymmetrical

Javier Pereda; Juan Dixon

2012-01-01

71

Modeling and analysis of cascaded H-bridge inverter for wind driven isolated squirrel cage induction generators  

Microsoft Academic Search

This paper describes the simulation model and the harmonics analysis of cascaded five level H-bridge inverters fed RL load and induction motor load system for stand alone applications. The SEIG fed H- bridge multi level inverter (MLI) for variable speed wind energy conversion systems are considered for various stand alone applications. In this paper, the SEIG fed cascaded five level

M. Sasikumar; R. Madhusudhanan; S. ChenthurPandian

2010-01-01

72

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

Microsoft Academic Search

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

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

2001-01-01

73

Double dark resonances and the dispersion properties in a four-level inverted-Y atomic system  

NASA Astrophysics Data System (ADS)

The electromagnetically induced transparency (EIT) and its dispersion properties in a four-level inverted-Y atomic system are investigated. The absorption spectrum of a weak probe field shows two EIT windows (dark resonances) whose location, width, and depth can be controlled by manipulating the parameters of the coupling fields; the corresponding dispersion properties are also measured by using a Mach-Zehnder interferometer. The experimental measurements agree well with the theoretical calculations. This kind of system can find important applications in two-channel quantum communication and information storage.

Kou, Jun; Wan, Ren-Gang; Kuang, Shang-Qi; Jiang, Li; Zhang, Liang; Kang, Zhi-Hui; Wang, Hai-Hua; Gao, Jin-Yue

2011-03-01

74

Inverting the Linear Algebra Classroom  

ERIC Educational Resources Information Center

The inverted classroom is a course design model in which students' initial contact with new information takes place outside of class meetings, and students spend class time on high-level sense-making activities. The inverted classroom model is so called because it inverts or "flips" the usual classroom design where typically class

Talbert, Robert

2014-01-01

75

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

E-print Network

-mass ultrasonic motor (MM- USM) via a LLCC-type filter. In order to specify the power supply requirements scheme is studied, and for attaining high dynamic performance, a cascaded voltage and hysteresis current is the multi-mass ultrasonic motor (MM-USM) derived from the well known travelling-wave type motor (TW

Paderborn, Universität

76

QUERY BY MULTI-TAGS WITH MULTI-LEVEL PREFERENCES FOR CONTENT-BASED MUSIC RETRIEVAL  

E-print Network

to it. The tags can include different types of musical information, such as genre, mood, instrumentationQUERY BY MULTI-TAGS WITH MULTI-LEVEL PREFERENCES FOR CONTENT-BASED MUSIC RETRIEVAL Ju-Chiang Wang content-based music retrieval system that accepts a query containing multiple tags with multiple levels

Wang, Hsin-Min

77

PROGRAMMING AT A HIGH-LEVEL ON MULTI-CORES  

E-print Network

PROGRAMMING AT A HIGH- LEVEL ON MULTI-CORES What is a compiler to do? Arun Chauhan Indiana University #12;Arun Chauhan, Indiana University HP Research, July 29, 2008 The Multi-core crisis · Physical limitations Transistor sizes Clock skew · Power consumption ·"Moore's Law" #12;Arun Chauhan, Indiana

Chauhan, Arun

78

A new diode clamping multilevel inverter  

Microsoft Academic Search

This paper proposes a new diode clamping multilevel Inverter, which gets rid of the need for series association of the clamping diodes in the conventional diode clamping multilevel inverter. The new diode clamping inverter utilizes the same number of switches and diodes as the conventional one for synthesizing an inverter of a given level. Operation fundamentals, clamping mechanism as well

Xiaoming Yuan; Ivo Barbi

1999-01-01

79

Multi-Level Sequential Pattern Mining Based on Prime Encoding  

NASA Astrophysics Data System (ADS)

Encoding is not only to express the hierarchical relationship, but also to facilitate the identification of the relationship between different levels, which will directly affect the efficiency of the algorithm in the area of mining the multi-level sequential pattern. In this paper, we prove that one step of division operation can decide the parent-child relationship between different levels by using prime encoding and present PMSM algorithm and CROSS-PMSM algorithm which are based on prime encoding for mining multi-level sequential pattern and cross-level sequential pattern respectively. Experimental results show that the algorithm can effectively extract multi-level and cross-level sequential pattern from the sequence database.

Lianglei, Sun; Yun, Li; Jiang, Yin

80

Building multi?level governance in Southeast Europe?  

Microsoft Academic Search

Drawing on the contributions to this volume, this concluding analysis reflects on the extent to which European Union (EU) cohesion policy and related pre?accession instruments are contributing to the development of more compound polities in Southeast Europe and, specifically, promoting multi?level governance. It argues that these EU policies have created more compound polities but that system?wide multi?level governance remains weak

Ian Bache

2010-01-01

81

Multi-level logic minimization through fault dictionary analysis  

E-print Network

MULTI-LEVEL LOGIC MINIMIZATION THROUGH FAULT DICTIONARY ANALYSIS A Thesis by RONALD W. MEHLER Submitted to the Office of Graduate Studies of Texas A@M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE... December 1998 Major Subject: Electrical Engineering MULTI-LEVEL LOGIC MINIMIZATION THROUGH FAULT DICTIONARY ANALYSIS A Thesis by RONALD W. MEHLER Submitted to Texas A&M University in partial fulfillment of the requirements for the degree of MASTER...

Mehler, Ronald W

2012-06-07

82

New multi-level codes over GF(q)  

NASA Technical Reports Server (NTRS)

Set partitioning to multi-dimensional signal spaces over GF(q), particularly GF sup q-1(q) and GF sup q (q), and show how to construct both multi-level block codes and multi-level trellis codes over GF(q). Two classes of multi-level (n, k, d) block codes over GF(q) with block length n, number of information symbols k, and minimum distance d sub min greater than or = d, are presented. These two classes of codes use Reed-Solomon codes as component codes. They can be easily decoded as block length q-1 Reed-Solomon codes or block length q or q + 1 extended Reed-Solomon codes using multi-stage decoding. Many of these codes have larger distances than comparable q-ary block codes, as component codes. Low rate q-ary convolutional codes, work error correcting convolutional codes, and binary-to-q-ary convolutional codes can also be used to construct multi-level trellis codes over GF(q) or binary-to-q-ary trellis codes, some of which have better performance than the above block codes. All of the new codes have simple decoding algorithms based on hard decision multi-stage decoding.

Wu, Jiantian; Costello, Daniel J., Jr.

1990-01-01

83

Profiles of Multi-Level Self-Management in Schools.  

ERIC Educational Resources Information Center

Examined how school-based management (SBM) at the school, group, and individual levels is related to school performance at different levels. From a sample of 82 Hong Kong schools, the strength of multi-level self-management in schools was found to be strongly related to quality indicators of organizational performance, and moderately correlated to

Cheng, Yin Cheong; Cheung, Wing Ming

2003-01-01

84

Series hybrid powertrain based on the dual two-level inverter  

Microsoft Academic Search

A multilevel converter in the 'dual two level' configuration is proposed as the core of a hybrid series powertrain. The generation system of the powertrain is constituted by an internal combustion engine (ICE) connected to a three-phase permanent magnet synchronous generator (PMSG). This machine is in the three phase open end winding configuration and is driven by the dual two-

Claudio Rossi; Gabriele Grandi; Piero Corbelli

2008-01-01

85

Space Vector Pulse Width Modulation Applied to the Three-Level Voltage Inverter  

Microsoft Academic Search

Advances in power electronics technology allowed the wide investigation of multilevel converters that provide high safety voltages with less harmonic components compared to the two-level structures. Employed for converter's gating signals generation, the space-vector pulse width modulation (SVPWM) strategy reduces the switching losses by limiting the switching to the two thirds of the pulse duty cycle. This study aims to

Hind Djeghloud; Hocine Benalla

86

A method for predicting the noise levels of coannular jets with inverted velocity profiles  

NASA Technical Reports Server (NTRS)

A coannular jet was equated with a single stream equivalent jet with the same mass flow, energy, and thrust. The acoustic characteristics of the coannular jet were then related to the acoustic characteristics of the single jet. Forward flight effects were included by incorporating a forward exponent, a Doppler amplification factor, and a Strouhal frequency shift. Model test data, including 48 static cases and 22 wind tunnel cases, were used to evaluate the prediction method. For the static cases and the low forward velocity wind tunnel cases, the spectral mean square pressure correlation coefficients were generally greater than 90 percent, and the spectral sound pressure level standard deviation were generally less than 3 decibels. The correlation coefficient and the standard deviation were not affected by changes in equivalent jet velocity. Limitations of the prediction method are also presented.

Russell, J. W.

1979-01-01

87

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

SciTech Connect

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.

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

88

Inapproximability of the Multi-level Uncapacitated Facility Location Problem  

E-print Network

Inapproximability of the Multi-level Uncapacitated Facility Location Problem Ravishankar-level uncapacitated facility location problem. In particular, we show that there is no polynomial time approximation the well known uncapacitated facility location problem (k = 1) since the best known approximation guarantee

Atkinson, Katie

89

SWIFT: Accelerated Proximity Queries Using Multi-Level Voronoi Marching  

E-print Network

to such a technique as "Voronoi marching" in this paper. Spatial locality and temporal coherence is captured by both algorithm between moving convex polyhedra. The algo- rithm combines Voronoi-based feature tracking with a multi-level-of-detail representation, in order to adapt to the variation in levels of coherence

North Carolina at Chapel Hill, University of

90

A general circuit topology of multilevel inverter  

Microsoft Academic Search

A generalized circuit topology of multilevel voltage source inverters which is based on a direct extension of the three-level inverter to higher level is proposed. The circuit topologies up to five-level are presented. The proposed multilevel inverter can realize any multilevel pulsewidth modulation (PWM) scheme which leads to harmonic reduction and provides full utilization of semiconductor devices like GTOs, especially

Nam S. Choi; Jung G. Cho; Gyu H. Cho

1991-01-01

91

Multi-stage decoding for multi-level block modulation codes  

NASA Technical Reports Server (NTRS)

In this paper, we investigate various types of multi-stage decoding for multi-level block modulation codes, in which the decoding of a component code at each stage can be either soft-decision or hard-decision, maximum likelihood or bounded-distance. Error performance of codes is analyzed for a memoryless additive channel based on various types of multi-stage decoding, and upper bounds on the probability of an incorrect decoding are derived. Based on our study and computation results, we find that, if component codes of a multi-level modulation code and types of decoding at various stages are chosen properly, high spectral efficiency and large coding gain can be achieved with reduced decoding complexity. In particular, we find that the difference in performance between the suboptimum multi-stage soft-decision maximum likelihood decoding of a modulation code and the single-stage optimum decoding of the overall code is very small: only a fraction of dB loss in SNR at the probability of an incorrect decoding for a block of 10(exp -6). Multi-stage decoding of multi-level modulation codes really offers a way to achieve the best of three worlds, bandwidth efficiency, coding gain, and decoding complexity.

Lin, Shu

1991-01-01

92

A Simple and Reliable PWM Synchronization & Phase-Shift Method for Cascaded H-Bridge Multilevel Inverters based on a Standard Serial Communication Protocol  

Microsoft Academic Search

The use of the CAN communication protocol for H-bridge multi-level (HBML) inverters, and localized PWM generation and AVR is proposed in this paper. It is shown that the performance and reliability of conventional distributed controllers for HBML inverters can be improved with less communication hardware requirements, when using the proposed method. It is also shown that the expansion and modularization

Young-Min Park; Han-Seong Yoo; Hyun-Won Lee; Myung-Gil Jung; Se-Hyun Lee; Choong-Dong Lee; Sang-Bin Lee; Ji-Yoon Yoo

2006-01-01

93

The multi-dimensional additionality of innovation policies. A multi-level application to Italy and Spain.  

E-print Network

1 The multi-dimensional additionality of innovation policies. A multi-level application to Italy, at the national and regional level (multi-level). An empirical application is carried out for Italy and Spain of different variables in Spain (product innovations) and in Italy (process innovations). Overall, only

Sussex, University of

94

Meeting the Challenges of a MultiLevel Class  

Microsoft Academic Search

This paper draws from my experiences teaching an intensive, multi-level, English as a Second Language class which students attended on an irregular basis. The first section considers the sociological factors which created this kind of learning situation. The second states my basic assumptions about teaching in an environment lacking both homogeneity and consistency. The third section relates strategies I developed

Valerie Berger

1982-01-01

95

Multi-Level Learning Processes in (Water) Resource Governance  

E-print Network

Multi-Level Learning Processes in (Water) Resource Governance Systems Claudia Pahl-Wostl Professor towards more Adaptive Governance in River Basins) GWSP (Global Water System Project) #12;Tradition ,,Messy" Problems ? Government & Technical Experts Governance by many actors #12;Paradigm Shift in Water

Slatton, Clint

96

Learning Dictionaries for Information Extraction by MultiLevel Bootstrapping  

Microsoft Academic Search

Information extraction systems usually require two dictionaries: a semantic lexicon and a dictionary of ex- traction patterns for the domain. We present a multi- level bootstrapping algorithm that generates both the semantic lexicon and extraction patterns simultane- ously. As input, our technique requires only unan- notated training texts and a handful of seed words for a category. We use a

Ellen Riloff; Rosie Jones

1999-01-01

97

PROCEEDINGS Open Access MKEM: a Multi-level Knowledge Emergence  

E-print Network

PROCEEDINGS Open Access MKEM: a Multi-level Knowledge Emergence Model for mining undiscovered and Text Mining in Bioinformatics (DTMBio) 2009 Hong Kong. 6 November 2009 Abstract Background: Since UPK by mining the biomedical literature. These earlier works, however, required substantial manual

Lee, Doheon

98

The Dubious Benefits of Multi-Level Modeling  

ERIC Educational Resources Information Center

This paper presents an argument against the wider adoption of complex forms of data analysis, using multi-level modeling (MLM) as an extended case study. MLM was devised to overcome some deficiencies in existing datasets, such as the bias caused by clustering. The paper suggests that MLM has an unclear theoretical and empirical basis, has not led

Gorard, Stephen

2007-01-01

99

Multi-level Method Understanding Using Microprints Stephane Ducasse  

E-print Network

object-oriented specific informa- tion. sv3D, developed by Marcus et al., presents lines as dots and each]. How- ever, sv3D is more a general visualization approach than a fine-grained one specialized to conveyMulti-level Method Understanding Using Microprints St´ephane Ducasse LSE-LISTIC Universit´e de

Ducasse, Stéphane

100

Multi-Level Alert Clustering for Intrusion Detection Sensor Data*  

E-print Network

Multi-Level Alert Clustering for Intrusion Detection Sensor Data* Ambareen Siraj Rayford B. Vaughn - Alert fusion is a promising research area in information assurance today. To increase trustworthiness. A unified architecture for intelligent alert fusion will essentially combine alert prioritization, alert

Siraj, Ambareen

101

A Novel topology and control strategy for maximum power point trackers and multi-string grid-connected PV inverters  

Microsoft Academic Search

The number of grid-connected photovoltaic (PV) systems is increasing noticeably. However, the high initial cost of such systems impedes their wide spread commercialization. This paper presents a new multi-string grid-connected converter topology and a simplified control strategy with a minimum number of components that considerably lowers the initial investment and increases the life time of the system. The proposed system

S. Ali Khajehoddin; Alireza Bakhshai; Praveen Jain

2008-01-01

102

Propagation delay dependence on channel fins and geometry aspect ratio of 16-nm multi-gate MOSFET inverter  

Microsoft Academic Search

Fin-type vertical channel field effect transistors (FETs) are promising alternatives for the sub-32-nm CMOS technologies. This work investigates the impact of fin number and structure on Vth degradation and transient behavior of devices and circuits. Vertical channel transistors with different fin aspect ratio (AR = the fin height \\/ the effective fin width) are explored. The multi-fin FinFETs (AR =

Hui-Wen Cheng; Chih-Hong Hwang; Yiming Li

2009-01-01

103

Multi-stage decoding for multi-level block modulation codes  

NASA Technical Reports Server (NTRS)

Various types of multistage decoding for multilevel block modulation codes, in which the decoding of a component code at each stage can be either soft decision or hard decision, maximum likelihood or bounded distance are discussed. Error performance for codes is analyzed for a memoryless additive channel based on various types of multi-stage decoding, and upper bounds on the probability of an incorrect decoding are derived. It was found that, if component codes of a multi-level modulation code and types of decoding at various stages are chosen properly, high spectral efficiency and large coding gain can be achieved with reduced decoding complexity. It was found that the difference in performance between the suboptimum multi-stage soft decision maximum likelihood decoding of a modulation code and the single stage optimum decoding of the overall code is very small, only a fraction of dB loss in SNR at the probability of an incorrect decoding for a block of 10(exp -6). Multi-stage decoding of multi-level modulation codes really offers a way to achieve the best of three worlds, bandwidth efficiency, coding gain, and decoding complexity.

Lin, Shu; Kasami, Tadao

1991-01-01

104

Cascade multilevel inverters for utility applications  

Microsoft Academic Search

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

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

1997-01-01

105

A multi-level method for sparse linear systems  

SciTech Connect

A multi-level method for the solution of sparse linear systems is introduced. The definition of the method is based on data from the coefficient matrix alone. An upper bound for the condition number is available for certain symmetric positive definite (SPD) problems. Numerical experiments confirm the analysis and illustrate the efficiency of the method for diffusion problems with discontinuous coefficients with discontinuities which are not aligned with the coarse meshes.

Shapira, Y.

1997-09-01

106

Multi-level and two-level models of the decay out of superdeformed bands  

E-print Network

We compare a multi-level statistical model with a two-level model for the decay out of superdeformed rotational bands in atomic nuclei. We conclude that while the models depend on different dimensionless combinations of the input parameters and differ in certain limits, they essentially agree in the cases where experimental data is currently available. The implications of this conclusion are discussed.

A. J. Sargeant; M. S. Hussein; A. N. Wilson

2005-02-10

107

On decoding of multi-level MPSK modulation codes  

NASA Technical Reports Server (NTRS)

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.

Lin, Shu; Gupta, Alok Kumar

1990-01-01

108

Advanced micromechanisms in a multi-level polysilicon technology  

SciTech Connect

Quad-level polysilicon surface micromachining technology, comprising three mechanical levels plus an electrical interconnect layer, is giving rise to a new generation of micro-electromechanical devices and assemblies. Enhanced components can not be produced through greater flexibility in fabrication and design. New levels of design complexity that include multi-level gears, single-attempt locks, and optical elements have recently been realized. Extensive utilization of the fourth layer of polysilicon differentiates these latter generation devices from their predecessors. This level of poly enables the fabrication of pin joints, linkage arms, hinges on moveable plates, and multi-level gear assemblies. The mechanical design aspects of these latest micromachines will be discussed with particular emphasis on a number of design aspects of these latest micromachines will be discussed with particular emphasis on a number of design modifications that improve the power, reliability, and smoothness of operation of the microengine. The microengine is the primary actuation mechanism that is being used to drive mirrors out of plane and rotate 1600-{mu}m diameter gears. Also discussed is the authors most advanced micromechanical system to date, a complex proof-of-concept batch-fabricated assembly that, upon transmitting the proper electrical code to a mechanical lock, permits the operation of a micro-optical shutter.

Rodgers, M.S.; Sniegowski, J.J.; Miller, S.L.; Barron, C.C.; McWhorter, P.J.

1997-08-01

109

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

SciTech Connect

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.

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

2009-01-01

110

On codes with multi-level error-correction capabilities  

NASA Technical Reports Server (NTRS)

In conventional coding for error control, all the information symbols of a message are regarded equally significant, and hence codes are devised to provide equal protection for each information symbol against channel errors. However, in some occasions, some information symbols in a message are more significant than the other symbols. As a result, it is desired to devise codes with multilevel error-correcting capabilities. Another situation where codes with multi-level error-correcting capabilities are desired is in broadcast communication systems. An m-user broadcast channel has one input and m outputs. The single input and each output form a component channel. The component channels may have different noise levels, and hence the messages transmitted over the component channels require different levels of protection against errors. Block codes with multi-level error-correcting capabilities are also known as unequal error protection (UEP) codes. Structural properties of these codes are derived. Based on these structural properties, two classes of UEP codes are constructed.

Lin, Shu

1987-01-01

111

Constrained Multi-Level Algorithm for Trajectory Optimization  

NASA Astrophysics Data System (ADS)

The emphasis on low cost access to space inspired many recent developments in the methodology of trajectory optimization. Ref.1 uses a spectral patching method for optimization, where global orthogonal polynomials are used to describe the dynamical constraints. A two-tier approach of optimization is used in Ref.2 for a missile mid-course trajectory optimization. A hybrid analytical/numerical approach is described in Ref.3, where an initial analytical vacuum solution is taken and gradually atmospheric effects are introduced. Ref.4 emphasizes the fact that the nonlinear constraints which occur in the initial and middle portions of the trajectory behave very nonlinearly with respect the variables making the optimization very difficult to solve in the direct and indirect shooting methods. The problem is further made complex when different phases of the trajectory have different objectives of optimization and also have different path constraints. Such problems can be effectively addressed by multi-level optimization. In the multi-level methods reported so far, optimization is first done in identified sub-level problems, where some coordination variables are kept fixed for global iteration. After all the sub optimizations are completed, higher-level optimization iteration with all the coordination and main variables is done. This is followed by further sub system optimizations with new coordination variables. This process is continued until convergence. In this paper we use a multi-level constrained optimization algorithm which avoids the repeated local sub system optimizations and which also removes the problem of non-linear sensitivity inherent in the single step approaches. Fall-zone constraints, structural load constraints and thermal constraints are considered. In this algorithm, there is only a single multi-level sequence of state and multiplier updates in a framework of an augmented Lagrangian. Han Tapia multiplier updates are used in view of their special role in diagonalised methods, being the only single update with quadratic convergence. For a single level, the diagonalised multiplier method (DMM) is described in Ref.5. The main advantage of the two-level analogue of the DMM approach is that it avoids the inner loop optimizations required in the other methods. The scheme also introduces a gradient change measure to reduce the computational time needed to calculate the gradients. It is demonstrated that the new multi-level scheme leads to a robust procedure to handle the sensitivity of the constraints, and the multiple objectives of different trajectory phases. Ref. 1. Fahroo, F and Ross, M., " A Spectral Patching Method for Direct Trajectory Optimization" The Journal of the Astronautical Sciences, Vol.48, 2000, pp.269-286 Ref. 2. Phililps, C.A. and Drake, J.C., "Trajectory Optimization for a Missile using a Multitier Approach" Journal of Spacecraft and Rockets, Vol.37, 2000, pp.663-669 Ref. 3. Gath, P.F., and Calise, A.J., " Optimization of Launch Vehicle Ascent Trajectories with Path Constraints and Coast Arcs", Journal of Guidance, Control, and Dynamics, Vol. 24, 2001, pp.296-304 Ref. 4. Betts, J.T., " Survey of Numerical Methods for Trajectory Optimization", Journal of Guidance, Control, and Dynamics, Vol.21, 1998, pp. 193-207 Ref. 5. Adimurthy, V., " Launch Vehicle Trajectory Optimization", Acta Astronautica, Vol.15, 1987, pp.845-850.

Adimurthy, V.; Tandon, S. R.; Jessy, Antony; Kumar, C. Ravi

112

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

E-print Network

. Index Terms--Fault diagnosis, fault tolerance, genetic algorithm, multilevel inverter, neural network introduced as an alternative in high power and medium voltage situations, and also multilevel inverter drive (MLID) systems have become a solution for high power drive applications. A multilevel inverter not only

Tolbert, Leon M.

113

Analysis and comparison of hybrid multilevel voltage source inverters  

Microsoft Academic Search

This paper analyzes different hybrid multilevel inverters for high-power applications. With these hybrid topologies, it is possible to minimize the number of series-connected inverters for a given number of levels and, consequently, to reduce the THD of output voltage. Moreover, this paper develops a comparison among different hybrid multilevel inverters, especially between binary and trinary hybrid multilevel inverters. Several points

Cassiano Rech; Humberto Pinheiro; H. A. Grundling; HClio L. Hey; J. R. Pinheiro

2002-01-01

114

A Cascade Multilevel Inverter Using a Single DC Source  

E-print Network

A Cascade Multilevel Inverter Using a Single DC Source Zhong Du1, Leon M. Tolbert2 3, John N multilevel inverter requires DC sources for 2 + 1 levels. Without requiring transformers, the scheme proposed sinusoidal output. Index Terms-- Multilevel Inverter, Fuel Cell I. INTRODUCTION A cascade multilevel inverter

Tolbert, Leon M.

115

A multi-level multi-scale approach to study essential genes in Mycobacterium tuberculosis  

PubMed Central

Background The set of indispensable genes that are required by an organism to grow and sustain life are termed as essential genes. There is a strong interest in identification of the set of essential genes, particularly in pathogens, not only for a better understanding of the pathogen biology, but also for identifying drug targets and the minimal gene set for the organism. Essentiality is inherently a systems property and requires consideration of the system as a whole for their identification. The available experimental approaches capture some aspects but each method comes with its own limitations. Moreover, they do not explain the basis for essentiality in most cases. A powerful prediction method to recognize this gene pool including rationalization of the known essential genes in a given organism would be very useful. Here we describe a multi-level multi-scale approach to identify the essential gene pool in a deadly pathogen, Mycobacterium tuberculosis. Results The multi-level workflow analyses the bacterial cell by studying (a) genome-wide gene expression profiles to identify the set of genes which show consistent and significant levels of expression in multiple samples of the same condition, (b) indispensability for growth by using gene expression integrated flux balance analysis of a genome-scale metabolic model, (c) importance for maintaining the integrity and flow in a protein-protein interaction network and (d) evolutionary conservation in a set of genomes of the same ecological niche. In the gene pool identified, the functional basis for essentiality has been addressed by studying residue level conservation and the sub-structure at the ligand binding pockets, from which essential amino acid residues in that pocket have also been identified. 283 genes were identified as essential genes with high-confidence. An agreement of about 73.5% is observed with that obtained from the experimental transposon mutagenesis technique. A large proportion of the identified genes belong to the class of intermediary metabolism and respiration. Conclusions The multi-scale, multi-level approach described can be generally applied to other pathogens as well. The essential gene pool identified form a basis for designing experiments to probe their finer functional roles and also serve as a ready shortlist for identifying drug targets. PMID:24308365

2013-01-01

116

Multi-Level Steganography: Improving Hidden Communication in Networks  

E-print Network

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...

Fraczek, Wojciech; Szczypiorski, Krzysztof

2011-01-01

117

LOW-VOLUME PFC RECTIFIER BASED ON NON-SYMMETRIC MULTI-LEVEL BOOST  

E-print Network

LOW-VOLUME PFC RECTIFIER BASED ON NON-SYMMETRIC MULTI-LEVEL BOOST CONVERTER Behzad Mahdavikhah-phase rectifier with power factor correction (PFC) based on a modified multi level boost converter topology. In comparison with the conventional boost-based systems and other multi-level solutions the new PFC rectifier

Prodiæ, Aleksandar

118

Multi-Level Bitmap Indexes for Flash Memory Storage  

SciTech Connect

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.

Wu, Kesheng; Madduri, Kamesh; Canon, Shane

2010-07-23

119

Evolution of neuroarchitecture, multi-level analyses and calibrative reductionism  

PubMed Central

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

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

2012-01-01

120

A multi-level typology of abstract visualization tasks.  

PubMed

The considerable previous work characterizing visualization usage has focused on low-level tasks or interactions and high-level tasks, leaving a gap between them that is not addressed. This gap leads to a lack of distinction between the ends and means of a task, limiting the potential for rigorous analysis. We contribute a multi-level typology of visualization tasks to address this gap, distinguishing why and how a visualization task is performed, as well as what the task inputs and outputs are. Our typology allows complex tasks to be expressed as sequences of interdependent simpler tasks, resulting in concise and flexible descriptions for tasks of varying complexity and scope. It provides abstract rather than domain-specific descriptions of tasks, so that useful comparisons can be made between visualization systems targeted at different application domains. This descriptive power supports a level of analysis required for the generation of new designs, by guiding the translation of domain-specific problems into abstract tasks, and for the qualitative evaluation of visualization usage. We demonstrate the benefits of our approach in a detailed case study, comparing task descriptions from our typology to those derived from related work. We also discuss the similarities and differences between our typology and over two dozen extant classification systems and theoretical frameworks from the literatures of visualization, human-computer interaction, information retrieval, communications, and cartography. PMID:24051804

Brehmer, Matthew; Munzner, Tamara

2013-12-01

121

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

NASA Technical Reports Server (NTRS)

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.

1980-01-01

122

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

NASA Astrophysics Data System (ADS)

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.

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

2014-05-01

123

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

PubMed

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

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

2013-01-01

124

Medical Image Segmentation Using Multi-level Set Partitioning with Topological Graph Prior  

E-print Network

Medical Image Segmentation Using Multi-level Set Partitioning with Topological Graph Prior Saif multi-region segmentation. We validate our algorithm with numerous abdominal and brain image databases and compare it to other multi-region segmentation methods to demonstrate its accuracy and computational

125

Multi-level recordable disc using signal waveform modulation recording method  

NASA Astrophysics Data System (ADS)

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.

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

126

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

NASA Astrophysics Data System (ADS)

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.

Kathalingam, Sebasthi Rani; Karantharaj, Porkumaran

2012-07-01

127

Optimum Fuel Cell Utilization with Multilevel Inverters Burak Ozpineci1  

E-print Network

Optimum Fuel Cell Utilization with Multilevel Inverters Burak Ozpineci1 1 Oak Ridge National of semiconductors, this paper proposes a level reduction control using a multilevel inverter. Level reduction and increased efficiency. In this paper, a multilevel inverter is used to overcome some problems associated

Tolbert, Leon M.

128

Novel multilevel inverter carrier-based PWM method  

Microsoft Academic Search

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

Leon M. Tolbert; Thomas G. Habetler

1999-01-01

129

An improved multi-frame integration technique for low light level image  

Microsoft Academic Search

Multi-frame integration is a common method used in the technique of image enhancement, but multi-frame cumulative method has a certain limitation for processing low light level image. In this paper an improved multi-frame integration technique based on the mode value theory is carried out, called mode multi-frame integration. Mathematical statistics is made on the grey scale values of all the

Li Chen; Yingfang Li; Jingquan Tian

2010-01-01

130

PWM Inverters Using Split-Wound Coupled Inductors  

Microsoft Academic Search

The number of output-voltage levels available in pulsewidth-modulated (PWM) voltage-source inverters can be increased by inserting a split-wound coupled inductor between the upper and lower switches in each inverter leg. Interleaved PWM control of both inverter-leg switches produces three-level PWM voltage waveforms at the center tap of the coupled inductor winding, representing the inverter-leg output terminal, with a PWM frequency

John Salmon; Jeffrey Ewanchuk; Andrew M. Knight

2009-01-01

131

Possibility of forming an inverted distribution over the rotational levels of nitrogen in an expanding gas stream  

Microsoft Academic Search

A number of theoretical papers have been devoted to an investigation of the relaxation kinetics of the population of a system of rotational levels of molecules in a stream of gas freely expanding from a sonic nozzle [13]. The complexity of the task of constructing models of relaxation and of collisions consistent in accuracy, however, as well as the difficulties

N. B. Bondarenko; A. I. Lukovnikov

1986-01-01

132

Fine Structure of Optical Energy Levels Scheme for Ni2+ Doped in Inverted Perovskite BaLiF3  

NASA Astrophysics Data System (ADS)

The aim of this paper is to calculate the fine structure of the optical energy levels scheme of BaLiF3:Ni2+ taken into account besides the spin-orbit interaction, also the spin-spin, orbit-orbit and spin-other-orbit interactions. The numerical theoretical crystal field parameters were computed using the model exchange charge calculations of crystal field, taking into account the effects of the covalent bond formation between the Ni2+ and F- ions. The Hamiltonian of the BaLiF3:Ni2+ system has been diagonalized in a complete basis set spanned by all wave functions of the 3d8 electron configuration. The comparison of the calculated energy levels with experimental data gives a satisfactory agreement, which confirms the model and used method.

Andreici, Emiliana-Laura; Avram, N. M.

2011-10-01

133

Antibiotic resistance shaping multi-level population biology of bacteria  

PubMed Central

Antibiotics have natural functions, mostly involving cell-to-cell signaling networks. The anthropogenic production of antibiotics, and its release in the microbiosphere results in a disturbance of these networks, antibiotic resistance tending to preserve its integrity. The cost of such adaptation is the emergence and dissemination of antibiotic resistance genes, and of all genetic and cellular vehicles in which these genes are located. Selection of the combinations of the different evolutionary units (genes, integrons, transposons, plasmids, cells, communities and microbiomes, hosts) is highly asymmetrical. Each unit of selection is a self-interested entity, exploiting the higher hierarchical unit for its own benefit, but in doing so the higher hierarchical unit might acquire critical traits for its spread because of the exploitation of the lower hierarchical unit. This interactive trade-off shapes the population biology of antibiotic resistance, a composed-complex array of the independent population biologies. Antibiotics modify the abundance and the interactive field of each of these units. Antibiotics increase the number and evolvability of clinical antibiotic resistance genes, but probably also many other genes with different primary functions but with a resistance phenotype present in the environmental resistome. Antibiotics influence the abundance, modularity, and spread of integrons, transposons, and plasmids, mostly acting on structures present before the antibiotic era. Antibiotics enrich particular bacterial lineages and clones and contribute to local clonalization processes. Antibiotics amplify particular genetic exchange communities sharing antibiotic resistance genes and platforms within microbiomes. In particular human or animal hosts, the microbiomic composition might facilitate the interactions between evolutionary units involved in antibiotic resistance. The understanding of antibiotic resistance implies expanding our knowledge on multi-level population biology of bacteria. PMID:23508522

Baquero, Fernando; Tedim, Ana P.; Coque, Teresa M.

2013-01-01

134

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

E-print Network

energy sources especially for vehicular applications. Different energy sources such as batteries, ultra-capacitors, fuel cells etc. are available. Usage of these varied energy sources alone or together in different combinations in automobiles requires...

Emani, Sriram S.

2011-08-08

135

Pixel-level Image Fusion Algorithms for Multi-camera Imaging System  

E-print Network

Pixel-level Image Fusion Algorithms for Multi-camera Imaging System A Thesis Presented of image fusion technologies in the multi sensor image fusion system and applications. With specific focus on pixel level image fusion, the process after the image registration is processed, we develop graphic user

Abidi, Mongi A.

136

Glueball masses in U(1) LGT using the multi-level algorithm  

E-print Network

The multi-level algorithm allows, at least for pure gauge theories, reliable measurement of exponentially small expectation values. The implementation of the algorithm depends strongly on the observable one wants to measure. Here we report measurement of glueball masses using the multi-level algorithm in 4 dimensional compact U(1) theory as a case study.

Majumdar, P; Koma, M

2003-01-01

137

Glueball masses in U(1) LGT using the multi-level algorithm  

Microsoft Academic Search

The multi-level algorithm allows, at least for pure gauge theories, reliable measurement of exponentially small expectation values. The implementation of the algorithm depends strongly on the observable one wants to measure. Here we report measurement of glueball masses using the multi-level algorithm in 4 dimensional compact U(1) theory as a case study.

P. Majumdara; Y. Koma; M. Koma

2004-01-01

138

Multi-level annotation in the Emu speech database management system  

E-print Network

Multi-level annotation in the Emu speech database management system Steve Cassidy a,*, Jonathan, is a general purpose speech database management system which supports complex multi- level annotations. Emu can reserved. Keywords: Speech databases; Speech annotation 1. Speech database systems In the last ten years

Harrington, Jonathan

139

Examining the Relationship Between Academic Optimism and Student Achivement: A Multi-Level Approach  

E-print Network

achievement by including student ethnicity in addition to other student background characteristics; and third, determine to what magnitude school context explains a schools level of academic optimism. The author utilized multi-level analysis to test...

Hallmark, Bryan S

2013-02-21

140

A low computation Space Vector PWM scheme for multilevel inverters based on fractal approach  

Microsoft Academic Search

This paper proposes a Space Vector based pulse width modulation scheme for multilevel inverters. The principle of fractals is employed to find the sector of operation. The scheme is simulated for a 5-level inverter and experimentally verified by using a 3-level inverter configuration. The 3-level inverter is realized by connecting dual 2-level inverters in open-end winding configuration. In the space

G. Shiny; M. R. Baiju

2010-01-01

141

Real-Time Selective Harmonic Minimization in Cascaded Multilevel Inverters  

E-print Network

4302 Real-Time Selective Harmonic Minimization in Cascaded Multilevel Inverters with Varying DC-level cascaded multilevel inverter with separate DC sources will be presented. As opposed to previous research in this area, the DC sources feeding the multilevel inverter are considered to be varying in time

Tolbert, Leon M.

142

Hybrid Multilevel Inverter with Single DC Haiwen Liu1  

E-print Network

Hybrid Multilevel Inverter with Single DC Source Haiwen Liu1 , Leon M. Tolbert1, 2 , Burak Ozpineci Knoxville, TN 37932 3. Parker-Hannifin Corp. Olive Branch, MI 38654 Abstract- A hybrid multilevel inverter 5-level hybrid inverter is tested, which is controlled by multilevel carrier-based PWM signals

Tolbert, Leon M.

143

An improved modulation strategy for a hybrid multilevel inverter  

Microsoft Academic Search

Multilevel cascaded and hybrid inverter systems conventionally use three level bipolar PWM for each individual inverter, with their carriers phase shifted to achieve maximum harmonic cancellation within each phase leg. This has been shown to give a harmonic performance equivalent to APOD modulation of a NPC multilevel inverter, when the switching frequencies are scaled to achieve the same number of

B. P. McGrath; D. G. Holmes; M. Manjrekar; T.A. Lipo

2000-01-01

144

Efficient predictive current control technique for multilevel voltage source inverters  

Microsoft Academic Search

In this paper a predictive current control technique for multilevel voltage source inverters (MVSI) is presented. The proposed method can be applied to any multilevel inverter for high-voltage high-power applications. Here, it is applied to a four-level neutral-point diode clamped voltage source inverter (NPDCVSI). The inverter is considered as a non-linear system with its thirty seven discrete space voltage vectors.

G. S. Perantzakis; F. H. Xepapas; S. N. Manias

2005-01-01

145

A generalized multilevel inverter topology with self voltage balancing  

Microsoft Academic Search

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,

Fang Zheng Peng

2001-01-01

146

A generalized multilevel inverter topology with self voltage balancing  

Microsoft Academic Search

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-damped multilevel inverters can be derived from the generalized inverter topology. Moreover,

Fang Z. Peng

2000-01-01

147

A Portable Runtime Interface For Multi-Level Memory Hierarchies  

E-print Network

implementations for multi-core/SMP machines, the STI Cell Broadband Engine, a distributed memory cluster, and disk runtimes and running on a cluster of SMP nodes, out-of- core algorithms on a Sony Playstation 3 pulling data from disk, and a cluster of Sony Playstation 3's. With this uniform interface, we achieve good

Aiken, Alex

148

Massive Multi-species, Multi-level NLTE Model Atmospheres for Novae in Outburst  

E-print Network

We have used our PHOENIX multi-purpose model atmosphere code to calculate atmospheric models that represent novae in the optically thick wind phases of their outburst. We have improved the treatment of NLTE effects by expanding the number of elements that are included in the calculations from 15 to 19, and the number of ionization stages from 36 to 87. The code can now treat a total of 10713 levels and 102646 lines in NLTE. Aluminum, P, K, and Ni are included for the first time in the NLTE treatment and most elements now have at least the lowest six ionization stages included in the NLTE calculation. We have investigated the effects of expanded NLTE treatment on the chemical concentration of astrophysically significant species in the atmosphere, the equilibrium structure of the atmosphere, and the emergent flux distribution. Although we have found general qualitative agreement with previous, more limited NLTE models, the expanded NLTE treatment leads to significantly different values for the size of many of the NLTE deviations. In particular, for the hottest model presented here (effective temperature of 35000 K), for which NLTE effects are largest, we find that the expanded NLTE treatment reduces the NLTE effects for these important variables: neutral Hydrogen concentration, pressure structure, and emergent far UV flux. Moreover, we find that the addition of new NLTE species may greatly affect the concentration of species that were already treated in NLTE, so that, generally, all species that contribute significantly to the electron reservoir or to the total opacity, or whose line spectrum overlaps or interlocks with that of a species of interest, must be treated in NLTE to insure an accurate result for any particular species.

C. Ian Short; Peter H. Hauschildt; E. Baron

1999-06-14

149

An aid in the teaching of multilevel inverters for high power applications  

Microsoft Academic Search

Multilevel inverters represent a high potential for realization of high power controllable conversion systems of different nature-rectifiers, inverters, high power amplifiers, etc. From the even more applied three-level inverter to the multiple AC stages VSI, different topologies are applied, with an increasing quantity of possible levels. Usually, the theory of multilevel inverters is presented with different definitions of the number

A.-C. Rufer

1995-01-01

150

? synthesis with regional pole assignment for a double inverted pendulum  

Microsoft Academic Search

Control of an inverted pendulum has been a benchmark example in demonstrating and motivating various controller design techniques. This paper makes a study of application of ? synthesis with regional pole assignment for stabilizing a double inverted pendulum system with some parametric uncertainties and designs state-feedback controller by solving a multi-objective controller synthesis problem. The researching results of this paper

Fu Caifen; Liu Yuyan; Tan Wen; Zhang Jinfang

2010-01-01

151

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

49 Transportation 4 2013-10-01 2013-10-01 false Example of an Intermediate...a Multi-Level Car Complying With Window Location Requirements-§...a Multi-Level Car Complying With Window Location Requirements...

2013-10-01

152

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

49 Transportation 4 2011-10-01 2011-10-01 false Example of an Intermediate...a Multi-Level Car Complying With Window Location Requirements-§...a Multi-Level Car Complying With Window Location Requirements...

2011-10-01

153

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

49 Transportation 4 2010-10-01 2010-10-01 false Example of an Intermediate...a Multi-Level Car Complying With Window Location Requirements-§...a Multi-Level Car Complying With Window Location Requirements...

2010-10-01

154

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

49 Transportation 4 2011-10-01 2011-10-01 false Example of an Intermediate...a Multi-Level Car Complying With Window Location Requirements-§...a Multi-Level Car Complying With Window Location Requirements...

2011-10-01

155

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

49 Transportation 4 2012-10-01 2012-10-01 false Example of an Intermediate...a Multi-Level Car Complying With Window Location Requirements-§...a Multi-Level Car Complying With Window Location Requirements...

2012-10-01

156

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

49 Transportation 4 2013-10-01 2013-10-01 false Example of an Intermediate...a Multi-Level Car Complying With Window Location Requirements-§...a Multi-Level Car Complying With Window Location Requirements...

2013-10-01

157

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

49 Transportation 4 2010-10-01 2010-10-01 false Example of an Intermediate...a Multi-Level Car Complying With Window Location Requirements-§...a Multi-Level Car Complying With Window Location Requirements...

2010-10-01

158

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

49 Transportation 4 2012-10-01 2012-10-01 false Example of an Intermediate...a Multi-Level Car Complying With Window Location Requirements-§...a Multi-Level Car Complying With Window Location Requirements...

2012-10-01

159

Hybrid triple-level-cell/multi-level-cell NAND flash storage array with chip exchangeable method  

NASA Astrophysics Data System (ADS)

This paper proposes a mix-and-match design method for triple level cell (TLC)/multi level cell (MLC) NAND flash hybrid and exchangeable storage arrays. A TLC-NAND flash provides an low cost and high capacity memory solution. However the reliability and access latency of TLC NAND flash are degraded from MLC NAND flash. Additionally, the block unit write is preferable for TLC NAND flash since the write order is complicated due to narrow data margin and write disturbance. The proposed solution combines TLC and MLC NAND flash memories for a storage array. To reduce access to TLC NAND flash, the stored data is screened and only the static frozen data are stored into TLC NAND flash with a Round-Robin frozen data collection algorithm (RR-FDCA). Furthermore, the proposed chip exchanging method extends the solid-state drive (SSD) lifetime without system suspending. As a result, in spite of moderate characteristics of TLC NAND flash, the proposed storage array can achieve 29% write energy saving and 56% write performance enhancement with 17% cost reduction, compared with the conventional MLC-only SSD.

Hachiya, Shogo; Johguchi, Koh; Miyaji, Kousuke; Takeuchi, Ken

2014-01-01

160

A multilevel inverter system for an induction motor with open-end windings  

Microsoft Academic Search

In this paper, a multilevel inverter system for an open-end winding induction motor drive is described. Multilevel inversion is achieved by feeding an open-end winding induction motor with two two-level inverters in cascade (equivalent to a three-level inverter) from one end and a single two-level inverter from the other end of the motor. The combined inverter system with open-end winding

V. T. Somasekhar; K. Gopakumar; M. R. Baiju; Krishna K. Mohapatra; L. Umanand

2005-01-01

161

Signals from Multi-Level Run-Length-Limited Modulation Recordings Using Partial Response Maximum Likelihood  

NASA Astrophysics Data System (ADS)

Multi-level (ML) modulation recording technology increases the capacity of standard compact disc (CD) and digital versatile disc (DVD) rewritable systems without making changes to the optical/mechanical unit. In this paper, we introduce partial response maximum likelihood (PRML) technology to increase the accuracy of reading multi level signals from a ML-Run-length-limited (ML-RLL) recorded disc. Traditional slicer detection is no longer suitable for detecting multi-level run-length-limited signals. We also show several partial-response methods and their corresponding maximum-likelihood sequential estimation (MLSE) rules for ML-RLL modulation signal detection.

Jiang, Sun-How; Kuo, Ji-Wen; Ma, Chang-Po; Lo, Feng-Hsiang

2005-05-01

162

Efficiency analysis for three phase grid-tied PV inverter  

Microsoft Academic Search

In this paper, the efficiency of the conventional two-level and three-level grid-connected inverter for the photovoltaic (PV) generation is analyzed. And the DC-link voltagepsilas influence on it is also studied. It can be seen that when the inverter does not control the gridpsilas frequency and voltage, a conventional three-level inverter has higher efficiency than that of a conventional two-level one,

Weimin Wu; XiaoLi Wang; Pan Geng; Tianhao Tang

2008-01-01

163

A Self-Organizing and Holonic Model for Optimization in MultiLevel Location Problems  

Microsoft Academic Search

Multi-Level Location Problems are generally considered as complex. To deal with these problems we propose an approach based on Holonic MultiAgent Systems (HMAS). HMAS have already proven to be a convenient way to engineer complex systems. This approach was merged with Artificial Potential Fields (APF) mechanims. The solution is obtained simultaneously with the holarchy. The holarchy is thus used to

Sana Moujahed; Nicolas Gaud; David Meignan

2007-01-01

164

BINAURAL MULTI-CHANNEL WIENER FILTERING FOR HEARING AIDS: PRESERVING INTERAURAL TIME AND LEVEL DIFFERENCES  

E-print Network

BINAURAL MULTI-CHANNEL WIENER FILTERING FOR HEARING AIDS: PRESERVING INTERAURAL TIME AND LEVEL.vandenbogaert,jan.wouters}@uz.kuleuven.be ABSTRACT This paper presents an extension of the binaural multi-channel Wiener filtering algorithm to preserve the binaural cues of both the speech and noise components without significantly compromizsing

165

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

E-print Network

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

Mackworth, Alan K.

166

Extended operation of flying capacitor multilevel inverters  

Microsoft Academic Search

Recent research in flying capacitor multilevel inverters (FCMIs) has shown that the number of voltage levels can be extended by changing the ratio of the capacitor voltages. For the three-cell FCMI, four levels of operation are expected if the traditional ratio of the capacitor voltages is 1:2:3. However, by altering the ratio, the inverter can operate as a five-, six-,

Jing Huang; Keith A. Corzine

2006-01-01

167

Space-vector PWM for inverters with split-wound coupled inductors  

Microsoft Academic Search

This paper proposes a space-vector pulse width modulation (SVPWM) technique suitable for inverters with a coupled inductor output. The proposed approach is based on multi-level SVPWM and can offer superior performance when compared to other modulation techniques suitable for coupled inductor topologies. In particular the approach addresses issues related to common mode DC current balance in a three-limb inductor core

B. Vafakhah; M. Masiala; J. Salmon; A. M. Knight

2009-01-01

168

Multilevel inverter for induction motor drives: Implementation using reversing voltage topology  

Microsoft Academic Search

Multi-level inverter technology has emerged recently as a very important alternative in the area of medium-voltage high-power energy control. Due to higher number of dc voltage sources, lower EMI, requirement of semiconductor power devices with less blocking voltage, lower % THD in output voltage and less stress on insulation, they are widely used. However, it has some disadvantages as complicated

Hemant Joshi; P. N. Tekwani; Amar Hinduja

2010-01-01

169

Multi-level scanning method for defect inspection  

DOEpatents

A method for performing scanned defect inspection of a collection of contiguous areas using a specified false-alarm-rate and capture-rate within an inspection system that has characteristic seek times between inspection locations. The multi-stage method involves setting an increased false-alarm-rate for a first stage of scanning, wherein subsequent stages of scanning inspect only the detected areas of probable defects at lowered values for the false-alarm-rate. For scanning inspection operations wherein the seek time and area uncertainty is favorable, the method can substantially increase inspection throughput.

Bokor, Jeffrey (Oakland, CA); Jeong, Seongtae (Richmond, CA)

2002-01-01

170

A multi-step and multi-level approach for computer aided molecular design  

Microsoft Academic Search

A general multi-step approach for setting up, solving and solution analysis of computer aided molecular design (CAMD) problems is presented. The approach differs from previous work within the field of CAMD since it also addresses the need for a computer aided problem formulation and result analysis. The problem formulation step incorporates a knowledge base for the identification and setup of

Peter M. Harper; Rafiqul Gani

2000-01-01

171

Multi-phase image segmentation using level sets  

NASA Astrophysics Data System (ADS)

A hierarchical multi-phase image segmentation using the original and a modified Chan-Vese 2-phase method is considered. A method of capturing features inside a pre-selected region of interest (ROI) is proposed that effectively restricts the segmentation operation to the ROI. At the first step, a modified image is created by setting the portion of the image outside the ROI to a uniform intensity equal to the mean image intensity inside the ROI. Effectively, this procedure partitions the initial image into two phases, in such a way that the ROI effectively becomes a 'segmented' feature. At the second step, the segmentation procedure is applied to the modified image, partitioning the image in two phases - object and background - inside the ROI. By confining segmentation to the ROI, it is shown, using an artificial image, that objects can be discriminated that could not have been found if segmentation had been performed on the entire image. If necessary, this second step can be repeated to further segment features of interest within the ROI, thereby providing a multi-phase segmentation procedure. ROI placement around features of interest requires prior knowledge, and may be derived from an atlas or manually prescribed by the operator. In this way, segmentation is possible on low-contrast features of interest, while ignoring features irrelevant for a particular application. Examples are provided for segmentation of several 2D/3D images performed both on entire images and inside a ROI.

Zhilkin, Peter; Alexander, Murray

2008-03-01

172

Low Voltage Multi-level Converters using Split-wound Coupled Inductors.  

E-print Network

??In low-voltage applications, an alternative approach to multi-level capacitorbased converters can be obtained by interleaving the switching of two converters across split-wound coupled inductors. When (more)

Ewanchuk, Jeffrey

2013-01-01

173

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

E-print Network

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...

Lewinski, Christi Nicole

2007-09-17

174

Don't Care Minimization of MultiLevel Sequential Logic Networks  

Microsoft Academic Search

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

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

1990-01-01

175

Recovery of muscle strength following multi-level orthopaedic surgery in diplegic cerebral palsy  

Microsoft Academic Search

Muscle strength changes following multi-level surgery in cerebral palsy and the impact of rehabilitation on functional recovery are largely unknown. The aim of this study was to quantify lower limb muscle strength changes in children with spastic diplegia after multi-level orthopaedic surgery and to compare the efficacy of progressive resistance strengthening (RS) versus active exercise (AE).Twenty children with spastic diplegia

Maria Seniorou; Nicky Thompson; Marian Harrington; Tim Theologis

2007-01-01

176

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

Microsoft Academic Search

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

Babak Rezaei Rowshan; Marzuki Bin Khalid; Rubiyah Yusof

2008-01-01

177

Trans-Z-source inverters  

Microsoft Academic Search

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

Wei Qian; Fang Zheng Peng; Honnyong Cha

2010-01-01

178

Trans-Z-Source Inverters  

Microsoft Academic Search

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 buck and boost function that cannot be achieved by traditional voltage-source inverters and current-source inverters.

Wei Qian; Fang Zheng Peng; Honnyong Cha

2011-01-01

179

Understanding Individual Level ERP Assimilation: A Multi-Case Study  

Microsoft Academic Search

Assimilation of enterprise resource planning (ERP) systems in organizations has been considered as one of the critical steps towards the realization of the intended benefits. This study extends the assimilation research from the organizational level to the individual level with the argument that ultimately it is the individual users who transform the systems' capability into organizational performance through daily activities.

Luning Liu; Yuqiang Feng; Qing Hu; Xiaojian Huang

2010-01-01

180

An efficient method to improve iris recognition performance based on multi-level fusion  

NASA Astrophysics Data System (ADS)

To improve the reliability and accuracy of iris-based identification system, this paper proposed an efficient method based on multi-level fusion. Multi-level fusion contains two levels: multialgorithmic fusion and multiinstance fusion. The multialgorithmic fusion integrates the improved phase algorithm and the DCT-based algorithm, and the multiinstance fusion combines information from left iris and right iris of an individual. Both multialgorithmic fusion and multiinstance fusion are carried out at the matching score level. The experimental results on the noisy iris database UBIRIS demonstrate that the proposed fusion schemes can perform better than the simple recognition systems.

Wang, Fenghua; Zhang, Xinman

2012-01-01

181

Multi-Level Information Systems. AIR Forum Paper 1978.  

ERIC Educational Resources Information Center

To support informational needs of day-to-day and long-range decision-making, many universities have developed their own data collection devices and institutional reporting systems. Often these models only represent a single point in time and do not effectively support needs at college and departmental levels. This paper identifies some of the more

Jones, Leighton D.; Trautman, DeForest L.

182

Embedding secret information into a dithered multi-level image  

Microsoft Academic Search

A coding scheme for secretly embedding character information into a dithered multilevel image is presented. This scheme inputs both a monotone image and secret information, which is converted to binary sequences, and it outputs a single dithered image. This image contains the character data of about 2 kByte in a dithered bilevel image 3 kByte in a dithered three-level image

Kiyoshi TANAKA; Yasuhiro NAKAMURA; Kineo MATSUI

1990-01-01

183

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

PubMed Central

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

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

2009-01-01

184

Comparison of Traditional Inverters and Z-Source Inverter  

Microsoft Academic Search

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,

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

2005-01-01

185

Multi-level sexual selection: Individual and family-level selection for mating success in a historical human population  

PubMed Central

Precopulatory sexual selection is the association between fitness and traits associated with mate acquisition. While sexual selection is generally recognized to be a powerful evolutionary force, most investigations are limited to characters belonging to individuals. A broader multi-level perspective acknowledges that individual fitness can be affected by aspects of mating success that are characters of groups, such as families. Parental mating success in polygynous or polyandrous human societies may exemplify traits under group-level sexual selection. Using fitness measures that account for age-structure, I measure multi-level selection for mate number over 55 years in a human population with declining rates of polygyny. Sexual selection had three components: individual-level selection for ever-mating (whether or not an individual mated) and individual- and family-level selection for polyandry and polygyny. Family- and individual-level selection for polygyny was equally strong, three times stronger than family-level selection for polyandry and more than an order of magnitude stronger than individual-level selection for polyandry. However, individual-level selection for polyandry and polygyny was more effective at explaining relative fitness variance than family-level selection. Selection for ever-mating was the most important source of sexual selection for fitness; variation for ever-mating explained 23% of relative fitness variance. PMID:23730758

Moorad, Jacob

2013-01-01

186

A Bayesian Multi-Level Factor Analytic Model of Consumer Price Sensitivities across Categories  

ERIC Educational Resources Information Center

Identifying price sensitive consumers is an important problem in marketing. We develop a Bayesian multi-level factor analytic model of the covariation among household-level price sensitivities across product categories that are substitutes. Based on a multivariate probit model of category incidence, this framework also allows the researcher to

Duvvuri, Sri Devi; Gruca, Thomas S.

2010-01-01

187

A note on the maximization version of the multi-level facility location problem  

Microsoft Academic Search

We show that the maximization version of the multi-level facility location problem can be approximated by a factor of 0.5. The only previously known result is a factor of 0.47 for the two-level case obtained recently by Bumb (Oper. Res. Lett. 29(4) (2001) 155).

Jiawei Zhang; Yinyu Ye

2002-01-01

188

A Multi-Level Examination of College and Its Influence on Ecumenical Worldview Development  

ERIC Educational Resources Information Center

This multi-level, longitudinal study investigated the ecumenical worldview development of 13,932 students enrolled in one of 126 institutions. Results indicated that the final hierarchical linear model, consisting of institution-and-student-level predictors as well as slopes explaining the relationships among some of these predictors, explained

Mayhew, Matthew J.

2012-01-01

189

Novel multilevel inverter carrier-based PWM method  

SciTech Connect

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.

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

1999-10-01

190

Performance of multi level error correction in binary holographic memory  

NASA Technical Reports Server (NTRS)

At the Optical Computing Lab in the Jet Propulsion Laboratory (JPL) a binary holographic data storage system was designed and tested with methods of recording and retrieving the binary information. Levels of error correction were introduced to the system including pixel averaging, thresholding, and parity checks. Errors were artificially introduced into the binary holographic data storage system and were monitored as a function of the defect area fraction, which showed a strong influence on data integrity. Average area fractions exceeding one quarter of the bit area caused unrecoverable errors. Efficient use of the available data density was discussed. .

Hanan, Jay C.; Chao, Tien-Hsin; Reyes, George F.

2004-01-01

191

Multi-Level High School Classes: Astronomy Diagnostic Test Results  

NASA Astrophysics Data System (ADS)

A content survey, the Astronomy Diagnostic Test (ADT) designed for undergraduate non-science astronomy courses, was administered as a post-course survey to five senior high classes in a Maryland high school. In 2001, the five classes chosen included all three levels of physics and an astronomy class. Each class had an even distribution of male and female students, with a total of 115 girls and 104 boys as subjects. Results of the survey include: (1) The Advanced Placement (AP) physics class scored highest and general physics lowest. (2) The AP class, most of whom will major in engineering or computer sciences, had a mean ADT score similar to post-course undergraduate non-science astronomy classes. (3) For all five classes, the girls had lower mean scores than the boys. (4) In two classes the girls' self-reported mean confidence was 40% lower than the boys' confidence; in the other three classes the confidence levels were the same. Additional detailed research was done on the three cosmology and ten physics questions in the ADT; girls outperformed the boys in only two of these thirteen questions.

Hubbard, R.; Hufnagel, B.

2001-12-01

192

Multi-level video content represntation and retrieval  

NASA Astrophysics Data System (ADS)

In this article, several practical algorithms are proposed to support content-based video analysis, modeling, representation, summarization, indexing, and access. First, a multilevel video database model is given. One advantage of this model is that it provides a reasonable approach to bridging the gap between low-level representative features and high-level semantic concepts from a human point of view. Second, several model-based video analysis techniques are proposed. In order to detect the video shots, we present a novel technique, which can adapt the threshold for scene cut detection to the activities of variant videos or even different video shots. A seeded region aggregation and temporal tracking technique is proposed for generating the semantic video objects. The semantic video scenes can then be generated from these extracted video access units (e.g., shots and objects) according to some domain knowledge. Third, in order to categorize video contents into a set of semantic clusters, an integrated video classification technique is developed to support more efficient multilevel video representation, summarization, indexing, and access techniques.

Fan, Jianping; Aref, Walid G.; Elmagarmid, Ahmed K.; Hacid, Mohand-Said; Marzouk, Mirette S.; Zhu, Xingquan

2001-10-01

193

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

NASA Technical Reports Server (NTRS)

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.

Brandt, A.

1979-01-01

194

Fabrication and characterization of multi-level hierarchical surfaces.  

PubMed

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

Bhushan, Bharat; Lee, Hyungoo

2012-01-01

195

Designing interconnection networks for multi-level packaging  

SciTech Connect

A central problem in building large scale parallel machines is the design of the interconnection network. Interconnection network design is largely constrained by packaging technology. The authors start with a generic set of packaging restrictions and evaluate different network organizations under a random traffic model. They identify families of networks (product of complete graphs, high degree deBruijn graphs) that they believe will be useful for multilevel packaging. Their results indicate that customizing the network topology to the packaging constraints is useful. Some of the general principles that arise out of this study are: (1) making the networks denser at the lower levels he packaging hierarchy has a significant positive impact on global communication performance; (2) it is better to organize a fixed amount of communication bandwidth as a smaller number of high bandwidth channels; (3) providing the processors with the ability to tolerate latencies (by using multithreading) is very useful in improving performance.

Raghunath, M.T.; Ranade, A. [Univ. of California, Berkeley, CA (United States). Computer Science Division

1993-12-31

196

Global Multi-Level Analysis of the 'Scientific Food Web'  

PubMed Central

We introduce a network-based index analyzing excess scientific production and consumption to perform a comprehensive global analysis of scholarly knowledge production and diffusion on the level of continents, countries, and cities. Compared to measures of scientific production and consumption such as number of publications or citation rates, our network-based citation analysis offers a more differentiated picture of the ecosystem of science. Quantifying knowledge flows between 2000 and 2009, we identify global sources and sinks of knowledge production. Our knowledge flow index reveals, where ideas are born and consumed, thereby defining a global scientific food web. While Asia is quickly catching up in terms of publications and citation rates, we find that its dependence on knowledge consumption has further increased. PMID:23378902

Mazloumian, Amin; Helbing, Dirk; Lozano, Sergi; Light, Robert P.; Borner, Katy

2013-01-01

197

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

NASA Astrophysics Data System (ADS)

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.

Shao, Meng; Pei, Jing; Yang, Bo

2013-12-01

198

Multi-photon dressing of an anharmonic superconducting many-level quantum circuit  

E-print Network

We report on the investigation of a superconducting anharmonic multi-level circuit that is coupled to a harmonic readout resonator. We observe multi-photon transitions via virtual energy levels of our system up to the fifth excited state. The back-action of these higher-order excitations on our readout device is analyzed quantitatively and demonstrated to be in accordance with theoretical expectation. By applying a strong microwave drive we achieve multi-photon dressing of our system which is dynamically coupled by a weak probe tone. The emerging higher-order Rabi sidebands and associated Autler-Townes splittings involving up to five levels of the investigated anharmonic circuit are observed. Experimental results are in good agreement with master equation simulations.

Jochen Braumller; Joel Cramer; Steffen Schlr; Hannes Rotzinger; Lucas Radtke; Alexander Lukashenko; Ping Yang; Michael Marthaler; Lingzhen Guo; Alexey V. Ustinov; Martin Weides

2014-10-13

199

Multi-level manual and autonomous control superposition for intelligent telerobot  

NASA Technical Reports Server (NTRS)

Space telerobots are recognized to require cooperation with human operators in various ways. Multi-level manual and autonomous control superposition in telerobot task execution is described. The object model, the structured master-slave manipulation system, and the motion understanding system are proposed to realize the concept. The object model offers interfaces for task level and object level human intervention. The structured master-slave manipulation system offers interfaces for motion level human intervention. The motion understanding system maintains the consistency of the knowledge through all the levels which supports the robot autonomy while accepting the human intervention. The superposing execution of the teleoperational task at multi-levels realizes intuitive and robust task execution for wide variety of objects and in changeful environment. The performance of several examples of operating chemical apparatuses is shown.

Hirai, Shigeoki; Sato, T.

1989-01-01

200

Metropolitan area income inequality and self-rated healtha multi-level study  

Microsoft Academic Search

We examined the association of income inequality measured at the metropolitan area (MA) and county levels with individual self-rated health. Individual-level data were drawn from 259,762 respondents to the March Current Population Survey in 1996 and 1998. Income inequality and average income were calculated from 1990 census data, the former using Gini coefficients. Multi-level logistic regression models were used. Controlling

Tony A. Blakely; Kimberly Lochner; Ichiro Kawachi

2002-01-01

201

A centralized multi-level water-filling algorithm for Dynamic Spectrum Management  

Microsoft Academic Search

In digital-subscriber-line (DSL) networks, the interference, or crosstalk, between multiple DSL lines can severely limit the data-rate of the lines. Level-2 Dynamic Spectrum Management (DSM) optimizes the transmit spectra of multiple DSL lines to mitigate such mutual interference. This paper proposes a centralized multi-level water-filling (MLWF) Level-2 DSM algorithm for optimizing the transmit spectra for multiple DSL lines at a

Hao Zou; Aakanksha Chowdhery; John M. Cioffi

2009-01-01

202

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

NASA Technical Reports Server (NTRS)

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.

Horton, Graham; Leutenegger, Scott T.

1993-01-01

203

A new multilevel inverter model NP without clamping diodes  

Microsoft Academic Search

This paper deals with a novel multilevel inverter neutral point (MNP). This system consists of a series of monodirectional and bidirectional switch. If one or several bidirectional power switches of this inverter burn out or to become ruined by reason an over voltage or depreciation, it stays in the previous level. Indeed, for a three-level NP to occur a defect

K. Arab Tehrani; I. Rasoanarivo; H. Andriatsioharana; F. M. Sargos

2008-01-01

204

A multilevel soft-switching inverter with inductor coupling  

Microsoft Academic Search

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,

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

2001-01-01

205

d-OptCom: Dynamic multi-level and multi-objective metabolic modeling of microbial communities.  

PubMed

Most microbial communities change with time in response to changes and/or perturbations in environmental conditions. Temporal variations in interspecies metabolic interactions within these communities can significantly affect their structure and function. Here, we introduce d-OptCom, an extension of the OptCom procedure, for the dynamic metabolic modeling of microbial communities. It enables capturing the temporal dynamics of biomass concentration of the community members and extracellular concentration of the shared metabolites, while integrating species- and community-level fitness functions. The applicability of d-OptCom was demonstrated by modeling the dynamic co-growth of auxotrophic mutant pairs of E. coli and by computationally assessing the dynamics and composition of a uranium-reducing community comprised of Geobacter sulfurreducens, Rhodoferax ferrireducens, and Shewanella oneidensis. d-OptCom was also employed to examine the impact of lactate vs acetate addition on the relative abundance of uranium-reducing species. These studies highlight the importance of simultaneously accounting for both species- and community-level fitness functions when modeling microbial communities, and demonstrate that the incorporation of uptake kinetic information can substantially improve the prediction of interspecies flux trafficking. Overall, this study paves the way for the dynamic multi-level and multi-objective analysis of microbial ecosystems. PMID:24742179

Zomorrodi, Ali R; Islam, Mohammad Mazharul; Maranas, Costas D

2014-04-18

206

Discriminative analysis of early Alzheimer's disease using multi-modal imaging and multi-level characterization with multi-classifier (M3).  

PubMed

Increasing attention has recently been directed to the applications of pattern recognition and brain imaging techniques in the effective and accurate diagnosis of Alzheimer's disease (AD). However, most of the existing research focuses on the use of single-modal (e.g., structural or functional MRI) or single-level (e.g., brain local or connectivity metrics) biomarkers for the diagnosis of AD. In this study, we propose a methodological framework, called multi-modal imaging and multi-level characteristics with multi-classifier (M3), to discriminate patients with AD from healthy controls. This approach involved data analysis from two imaging modalities: structural MRI, which was used to measure regional gray matter volume, and resting-state functional MRI, which was used to measure three different levels of functional characteristics, including the amplitude of low-frequency fluctuations (ALFF), regional homogeneity (ReHo) and regional functional connectivity strength (RFCS). For each metric, we computed the values of ninety regions of interest derived from a prior atlas, which were then further trained using a multi-classifier based on four maximum uncertainty linear discriminant analysis base classifiers. The performance of this method was evaluated using leave-one-out cross-validation. Applying the M3 approach to the dataset containing 16 AD patients and 22 healthy controls led to a classification accuracy of 89.47% with a sensitivity of 87.50% and a specificity of 90.91%. Further analysis revealed that the most discriminative features for classification are predominantly involved in several default-mode (medial frontal gyrus, posterior cingulate gyrus, hippocampus and parahippocampal gyrus), occipital (fusiform gyrus, inferior and middle occipital gyrus) and subcortical (amygdale and pallidum of lenticular nucleus) regions. Thus, the M3 method shows promising classification performance by incorporating information from different imaging modalities and different functional properties, and it has the potential to improve the clinical diagnosis and treatment evaluation of AD. PMID:22008370

Dai, Zhengjia; Yan, Chaogan; Wang, Zhiqun; Wang, Jinhui; Xia, Mingrui; Li, Kuncheng; He, Yong

2012-02-01

207

Coaching competency and satisfaction with the coach: a multi-level structural equation model.  

PubMed

The purpose of this initial predictive validity study was to determine the ability of measures derived from the Athletes' Perceptions of Coaching Competency Scale II-High School Teams (APCCS II-HST) to predict satisfaction with the head coach. Specification of the statistical model was informed by the mediational model of coach-athlete interactions. The technical quality of the satisfaction measure was evaluated before testing the predictive validity of the coaching competency measures. Data were collected from athletes of seven sports. Athlete observations (N=748) were clustered within teams (G=74). Multi-group confirmatory factor analyses (CFA) provided evidence for factorial invariance of a reduced version of the satisfaction measure by athlete gender. Multi-level CFA provided evidence of model-data consistency for a reduced version of the satisfaction measure. Multi-level structural equation modelling provided evidence for the ability of latent coaching competency to positively predict latent satisfaction at both the athlete level (technique competency and motivation competency) and the team level (coaching competency) and for close model-data fit. Implications of this study include: that the APCCS II-HST should be viewed as a replacement for the Coaching Competency Scale when the intended population is appropriate; a preliminary multi-level measurement model for satisfaction with one's coach that should be considered as a potential starting point in subsequent studies; and empirical support for a key relationship proposed in the mediational model of coach-athlete interactions. PMID:21184342

Myers, Nicholas D; Beauchamp, Mark R; Chase, Melissa A

2011-02-01

208

Harmonic modeling of three-phase neutral-point inverters  

Microsoft Academic Search

The paper derives a closed-form analytical approximation of the output currents harmonic spectra for the three-phase neutral-point inverters under the action of hysteresis current control. The model is an extension of the recently developed model for single-phase two-level hysteresis inverters. The model derives the instantaneous frequency of the inverter and then uses it to approximate the error currents by frequency-modulated

Ahmad Albanna; C. J. Hatziadoniu

2009-01-01

209

Power inverter topologies for photovoltaic modules-a review  

Microsoft Academic Search

This review-paper focuses on the latest development of inverters for photovoltaic AC-modules. The power range for these inverters is usually within 90 Watt to 500 Watt, which covers the most commercial photovoltaic-modules. Self-commutated inverters have replaced the grid-commutated ones. The same is true for the bulky low-frequency transformers versus the high-frequency transformers, which are used to adapt the voltage level.

Soeren Baekhoej Kjaer; John K. Pedersen; Frede Blaabjerg

2002-01-01

210

Performance improvement of DTC for induction machine-fed by photovoltaic multilevel voltage source inverter  

Microsoft Academic Search

In this work, a sensorless Direct Torque Control (DTC) strategy of a five-level Neutral Point Clamped inverter-fed induction machine is presented. Multilevel inverters are an emerging technology and are commonly applied to high power motion drives instead of the standard two-level voltage source inverters (VSI). In five-level inverters the blocking voltage of each switch is 1\\/4 of the DC bus

Iqbal Messaf; El-Madjid Berkouk; Nadia Saadia

211

Multi level boarding bi-level commuter car for North American market  

Microsoft Academic Search

A multilevel boarding version (low and high level platform boarding) of the bi-level commuter car for the North American market has been developed. The major challenge of the bi-level carbody design with the high and lower boarding access, i.e., passenger doors, is the side sill interruption at the lower level. The side sill is the main structural member (beside the

R. Sarunac; T. B. Soesbee; S.-I. Ohta

2004-01-01

212

Neighborhood-Level Correlates of Consistent Condom Use among Men Who have Sex with Men: A Multi-Level Analysis  

PubMed Central

There is growing evidence that the neighborhood environment influences sexual behavior and related outcomes, but little work has focused specifically on men who have sex with men (MSM). Using interview data from a probability sample of 385 young MSM living in New York City, recruited at public venues in 1999 and 2000 as part of the Young Mens Survey-New York City, and data on neighborhood characteristics obtained from the U.S. Census 2000, we conducted multi-level analyses of the associations between neighborhood-level characteristics and consistent condom use during anal intercourse, while controlling for individual-level sociodemographic and other factors. After adjusting for individual-level factors, neighborhood-level gay presence remained significantly and positively associated with consistent condom use during anal intercourse. This finding suggests that neighborhoods with a significant gay presence may have norms that act to discourage high risk sexual activity. PMID:18712593

Koblin, Beryl; Chin, John; Beard, John; Blaney, Shannon; Halkitis, Perry; Vlahov, David; Galea, Sandro

2014-01-01

213

Resonant snubber inverter  

DOEpatents

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.

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

214

Resonant snubber inverter  

DOEpatents

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.

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

215

Analysis of a cluster randomized trial with binary outcome data using a multi-level model.  

PubMed

The use of multi-level logistic regression models was explored for the analysis of data from a cluster randomized trial investigating whether a training programme for general practitioners' reception staff could improve women's attendance at breast screening. Twenty-six general practices were randomized with women nested within them, requiring a two-level model which allowed for between-practice variability. Comparisons were made with fixed effect (FE) and random effects (RE) cluster summary statistic methods, ordinary logistic regression and a marginal model based on generalized estimating equations with robust variance estimates. An FE summary statistic method and ordinary logistic regression considerably understated the variance of the intervention effect, thus overstating its statistical significance. The marginal model produced a higher statistical significance for the intervention effect compared to that obtained from the RE summary statistic method and the multi-level model. Because there was only a moderate number of practices and these had unbalanced cluster sizes, reliable asymptotic properties for the robust standard errors used in the marginal model may not have been achieved. While the RE summary statistic method cannot handle multiple covariates easily, marginal and multi-level models can do so. In contrast to multi-level models however, marginal models do not provide direct estimates of variance components, but treat these as nuisance parameters. Estimates of the variance components were of particular interest in this example. Additionally, parametric bootstrap methods within the multi-level model framework provide confidence intervals for these variance components, as well as a confidence interval for the effect of intervention which allows for the imprecision in the estimated variance components. The assumption of normality of the random effects can be checked, and the models extended to investigate multiple sources of variability. PMID:10986541

Omar, R Z; Thompson, S G

2000-10-15

216

Achievable capacity improvement by using multi-level modulation format in trench-assisted multi-core fiber system.  

PubMed

We evaluate the impacts of using multi-level modulation formats on the transmission capacity of the multi-core fiber (MCF) having trench-assisted index profile and hexagonal layout. For this evaluation, we utilize the spectral efficiency per unit area, defined as the spatial spectral efficiency (SSE). The results show that the SSE improvement achievable by using the higher-level modulation format can be reduced due to its lower tolerance to the inter-core crosstalk. We also evaluate the effects of using large effective area on the transmission capacity of the trench-assisted MCF. The results show that the use of large effective area can decrease this capacity due to the increased inter-core crosstalk and lengthened cable cutoff wavelength, although it can help increase the transmission distance. Thus, it is necessary to optimize the effective area of MCF by considering both the SSE and transmission distance. However, the results indicate that the effect of using different effective areas on the SSE-distance product is not significant, and it is not useful to increase the effective area of the trench-assisted MCF to be larger than ~110 ?m(2). PMID:23787615

Chang, J H; Choi, H G; Chung, Y C

2013-06-17

217

Thread fork\\/join techniques for multi-level parallelism exploitation in NUMA multiprocessors  

Microsoft Academic Search

This paper presents some techniques for efficient t hread forking and joining in parallel execution environments, taking into consideration the physical structure of NUMA machines and the support for multi-level parallelization and p rocessor grouping. T wo work g eneration schemes and one join mechanism are designed, implemented, evaluated and compared with the ones used in the IRIX MP library,

Xavier Martorell; Eduard Ayguad; Nacho Navarro; Julita Corbaln; Marc Gonzlez; Jess Labarta

1999-01-01

218

Multi-Level Research on Youth Participation in the Haitian Reconstruction  

ERIC Educational Resources Information Center

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

Pluim, Gary W. J.

2012-01-01

219

Europeanization and new patterns of multi?level governance in Romania  

Microsoft Academic Search

This study considers whether EU cohesion policy and related pre?accession instruments have contributed to the development of a more compound polity in Romania and, specifically, considers the extent to which there is a process of Europeanization characterized by emergent features of multi?level governance. In particular, it brings forward a number of explanatory factors which account for the process of regions'

Ana Maria Dobre

2010-01-01

220

Refinement and validation of a multi-level assessment method for Mid-Atlantic tidal wetlands  

E-print Network

Refinement and validation of a multi-level assessment method for Mid-Atlantic tidal wetlands (EPA of wetland resources across the Mid-Atlantic physiographic region, efforts are currently underway in a number of states, most notably Delaware, Maryland, Pennsylvania and Virginia, to develop and implement wetland

221

Multi-study Integration of Brain Cancer Transcriptomes Reveals Organ-Level Molecular Signatures  

E-print Network

Multi-study Integration of Brain Cancer Transcriptomes Reveals Organ-Level Molecular Signatures for the primary classes of brain cancers to study the feasibility of separating all of these diseases ­ Identification of Structured Signatures and Classifiers (ISSAC) ­ that resulted in a brain cancer marker panel

Geman, Donald

222

A Multi-Level Context-Dependent Prosodic Model Applied to Durational Modeling  

E-print Network

in many applications of high-quality speech synthesis such as multi-media (avatar, video game, story telling) and artistic (theater, music) applications. Despite growing atten- tion to prosody modeling over and estimate the effects of high-level linguistic features (syntactic, semantic, discursive) on the observed

Paris-Sud XI, Université de

223

Consumer Boycotts and Farm Labor Welfare: A MultiLevel Market Analysis  

Microsoft Academic Search

The paper addresses the economics of recent boycott strategies and impacts of the agreements on labor and industry. A multi-level market model is used to address the linkage between Taco Bell, growers and labor. Analysis of the resulting segmentation of the labor market is also included.

Jamille Palacios; Robert D. Emerson; John J. VanSickle

2006-01-01

224

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

Microsoft Academic Search

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

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

225

The Development of Multi-Level Audio-Visual Teaching Aids for Earth Science.  

ERIC Educational Resources Information Center

The project consisted of making a multi-level teaching film titled "Rocks and Minerals of the Ouachita Mountains," which runs for 25 minutes and is in color. The film was designed to be interesting to earth science students from junior high to college, and consists of dialogue combined with motion pictures of charts, sequential diagrams, outcrops,

Pitt, William D.

226

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...

227

Multi-level optimization of a beam-like space truss utilizing a continuum model  

NASA Technical Reports Server (NTRS)

A continuous beam model is developed for approximate analysis of a large, slender, beam-like truss. The model is incorporated in a multi-level optimization scheme for the weight minimization of such trusses. This scheme is tested against traditional optimization procedures for savings in computational cost. Results from both optimization methods are presented for comparison.

Yates, K.; Gurdal, Z.; Thangjitham, S.

1992-01-01

228

Automatic Multi-organ Segmentation Using Learning-Based Segmentation and Level Set  

E-print Network

segmentation system for the fully automatic multi-organ segmentation from CT medical images. Thereby we combine accuracy and the straightforward prevention of segment overlaps. In a benchmark on 10­100 annotated accuracies of 1.17­2.89mm average surface errors. Thereby the level set segmentation (which is initialized

229

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

E-print Network

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

Skubic, Marjorie

230

Multi-objective design strategy for high-level low power design of DSP systems  

Microsoft Academic Search

High-level power design presents a complex, multi- objective problem that involves the simultaneous optimisation of competing criteria such as speed, area and power. It is difficult to combine these objectives into a single cost function, as this effectively requires prioritisation of the parameters, which may reduce the overall quality of the solution. A superior approach is to simultaneously optimise all

Mark S. Bright; Tughrul Arslan

1999-01-01

231

Laminoplasty versus laminectomy for multi-level cervical spondylotic myelopathy: a systematic review of the literature  

PubMed Central

Background There is considerable controversy as to which posterior technique is best for the treatment of multi-level cervical spondylotic myelopathy. The aim of this study was to compare the clinical and radiographic results and complications of laminoplasty (LAMP) and laminectomy (LAMT) in the treatment of multi-level cervical spondylotic myelopathy. Methods We reviewed and analyzed papers published from January 1966 and June 2013 regarding the comparison of LAMP and LAMT for multi-level cervical spondylotic myelopathy. Statistical comparisons were made when appropriate. Results Fifteen studies were included in this systematic review. There was no significant difference in the incidence of surgical complications between LAMP and LAMT. Compared to conventional LAMT and skip LAMT, postoperative ROM was more limited in LAMP, but this was still superior to postoperative ROM following LAMT with fusion. Postoperative kyphosis occurred in 8/180 (4.44%) in LAMP and 13/205 (6.34%) in LAMT, whereas no cases of kyphosis were reported for skip LAMT. Skip LAMT appears to have better clinical outcomes than LAMP, while the outcome was similar between LAMP and LAMT with fusion. Conclusions Based on these results, a claim of superiority for laminoplasty or laminectomy was not justified. In deciding between the two procedures, the risks of surgical and neurological complications, and radiologic and clinical outcome, must be taken into consideration if both options are available in multi-level cervical spondylotic myelopathy. PMID:24289653

2013-01-01

232

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

E-print Network

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

Wachs, Juan

233

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

E-print Network

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

Bargiela, Andrzej

234

Measurement of Low Level Explosives Reaction in Gauged MultiDimensional Steven Impact Tests  

Microsoft Academic Search

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.

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

2001-01-01

235

Multi-level Steering in Distributed Laboratories Beth Plale and Karsten Schwan  

E-print Network

Multi-level Steering in Distributed Laboratories Beth Plale and Karsten Schwan College of Computing Georgia Institute of Technology Atlanta, Georgia 30332 Abstract HPC end users in distributed computational, and shared computational tools. In such settings, there may be substantial differences in the resources

Plale, Beth

236

Multi-Level Selection and the Explanatory Value of Mathematical Decompositions  

E-print Network

is interested. ?is char- acter of interest will conventionally be a pro-social character such as a lions be- ing inclined to hunt cooperatively or a vampire bats being inclined to donate blood to other vampire bats who are in need. ?e multi-level Price...

Clarke, Christopher

2014-01-01

237

Aiding multi-level decision-making processes for climate change mitigation and adaptation  

E-print Network

, climate policy integration in Spain's Comunidad Valenciana, and food security in Bangladesh's Faridpur1 Aiding multi-level decision-making processes for climate change mitigation and adaptation Engineering and Geodezy, 1 Hr. Smirnenski blvd, 1046 Sofia, Bulgaria 6 Climate change and spatial development

Paris-Sud XI, Université de

238

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

ERIC Educational Resources Information Center

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

Blatt, Benjamin; Greenberg, Larrie

2007-01-01

239

Janus ultrathin film from multi-level self-assembly at air-water interfaces.  

PubMed

Ultrathin free-standing Janus films were fabricated at air-water interfaces using azopyridine derivatives and poly(acrylic acid) via multi-level self-assembly on molecular and microscopic scales, which showed distinct asymmetric water wetting abilities on different surfaces. PMID:25322840

Zhang, Hongbin; Hao, Rui; Jackson, John K; Chiao, Mu; Yu, Haifeng

2014-10-30

240

HR flexibility and firm performance: analysis of a multi-level causal model  

Microsoft Academic Search

Human resource flexibility as a construct, how it develops, and its effect on firm performance have not received adequate attention in strategic HRM literature in spite of their obvious importance in today's dynamic competitive environment. Based on a study of 98 manufacturing and 103 service firms in India, this paper addresses these issues by developing and testing a multi-level model

Sumita Ketkar; P. K. Sett

2009-01-01

241

Applying a revised VAM to a multi-level capacitated facility location problem  

Microsoft Academic Search

In this paper we developed a cost-varied Vogel-based approximation method, namely the Dynamic Vogel Approximation Method (DVAM), to solve a multi-level capacitated facility location problem (MCFLP), of which each client will be served by all levels of facilities with limited capacities. We discuss two kinds of MCFLP which are derived from two kinds of demand structures. The proposed algorithm is

Ying-Yen Chen; Hsiao-Fan Wang

2007-01-01

242

An Overview of the COBRA-ABS High Level Synthesis System for Multi-FPGA Systems  

Microsoft Academic Search

This paper presents an overview of the COBRA-ABS behavioural high-level synthesis tool. COBRA-ABS has been designed to synthesise custom architectures for arithmetic intensive algorithms, specified in C, for implementation on multi-FPGA Custom Computing Machine (FCCM) platforms. It performs globally optimising high level synthesis using simulated annealing, integrating all partitioning, scheduling, binding and allocation operations in one optimisation step, and has

Andrew A. Duncan; David C. Hendry; Peter Gray

1998-01-01

243

An inverter/controller subsystem optimized for photovoltaic applications  

NASA Technical Reports Server (NTRS)

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.

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

1978-01-01

244

Laser printing of conformal and multi-level 3D interconnects  

NASA Astrophysics Data System (ADS)

A crucial challenge in three-dimensional multi-chip assemblies is to establish electrical connections between discrete devices. Here, we apply laser printing of congruent voxels of silver nanopaste for the fabrication of conformal and 3D multi-level interconnects. By controlling laser fluence, various 3D electrodes including freestanding tabs and side contacts over vertical walls can be directly printed without the need for sacrificial layers, chemical etching or electroplating. The electrical characteristics of the printed interconnects are similar to those currently in use by the semiconductor industry. These results are a promising step forward in the generation of customized interconnects for 3D microelectronics.

Kim, H.; Duocastella, M.; Charipar, K. M.; Auyeung, R. C. Y.; Piqu, A.

2013-10-01

245

Harmonic interaction between large numbers of photovoltaic inverters and the distribution network  

Microsoft Academic Search

The dominating mechanisms of interaction between large populations of PV inverters and the electrical distribution network are investigated. Some demonstration projects with large number of small PV-inverters in a low voltage network, show high levels of voltage distortion, although the emission level of an individual PV inverter satisfy the PQ standards. The main object of this paper is to analyse

Johan H. r. Enslin; W. T. J. Hulshorst; A. M. S. Atmadji; P. J. M. Heskes; A. Kotsopoulos; J. F. G. Cobben; P. Van der Sluijs

2003-01-01

246

Invert emulsion well servicing fluids  

SciTech Connect

An invert emulsion well servicing fluid containing an oleaginous phase, an aqueous phase, an invert emulsifier and an effective amount of a solid, particulate polyolefin having a density of about 0.90 gms/cc or greater.

Carnicom, W.M.

1982-03-13

247

Energy-Saving Inverter  

NASA Technical Reports Server (NTRS)

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.

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

1984-01-01

248

A prospective, multi-method, multi-disciplinary, multi-level, collaborative, social-organisational design for researching health sector accreditation [LP0560737  

PubMed Central

Background Accreditation has become ubiquitous across the international health care landscape. Award of full accreditation status in health care is viewed, as it is in other sectors, as a valid indicator of high quality organisational performance. However, few studies have empirically demonstrated this assertion. The value of accreditation, therefore, remains uncertain, and this persists as a central legitimacy problem for accreditation providers, policymakers and researchers. The question arises as to how best to research the validity, impact and value of accreditation processes in health care. Most health care organisations participate in some sort of accreditation process and thus it is not possible to study its merits using a randomised controlled strategy. Further, tools and processes for accreditation and organisational performance are multifaceted. Methods/design To understand the relationship between them a multi-method research approach is required which incorporates both quantitative and qualitative data. The generic nature of accreditation standard development and inspection within different sectors enhances the extent to which the findings of in-depth study of accreditation process in one industry can be generalised to other industries. This paper presents a research design which comprises a prospective, multi-method, multi-level, multi-disciplinary approach to assess the validity, impact and value of accreditation. Discussion The accreditation program which assesses over 1,000 health services in Australia is used as an exemplar for testing this design. The paper proposes this design as a framework suitable for application to future international research into accreditation. Our aim is to stimulate debate on the role of accreditation and how to research it. PMID:16968552

Braithwaite, Jeffrey; Westbrook, Johanna; Pawsey, Marjorie; Greenfield, David; Naylor, Justine; Iedema, Rick; Runciman, Bill; Redman, Sally; Jorm, Christine; Robinson, Maureen; Nathan, Sally; Gibberd, Robert

2006-01-01

249

A 3D radiative transfer framework: XI. multi-level NLTE  

E-print Network

Multi-level non-local thermodynamic equilibrium (NLTE) radiation transfer calculations have become standard throughout the stellar atmospheres community and are applied to all types of stars as well as dynamical systems such as novae and supernovae. Even today spherically symmetric 1D calculations with full physics are computationally intensive. We show that full NLTE calculations can be done with fully 3 dimensional (3D) radiative transfer. With modern computational techniques and current massive parallel computational resources, full detailed solution of the multi-level NLTE problem coupled to the solution of the radiative transfer scattering problem can be solved without sacrificing the micro physics description. We extend the use of a rate operator developed to solve the coupled NLTE problem in spherically symmetric 1D systems. In order to spread memory among processors we have implemented the NLTE/3D module with a hierarchical domain decomposition method that distributes the NLTE levels, radiative rates,...

Hauschildt, Peter H

2014-01-01

250

Interestingness measures and strategies for mining multi-ontology multi-level association rules from gene ontology annotations for the discovery of new GO relationships.  

PubMed

The Gene Ontology (GO), a set of three sub-ontologies, is one of the most popular bio-ontologies used for describing gene product characteristics. GO annotation data containing terms from multiple sub-ontologies and at different levels in the ontologies is an important source of implicit relationships between terms from the three sub-ontologies. Data mining techniques such as association rule mining that are tailored to mine from multiple ontologies at multiple levels of abstraction are required for effective knowledge discovery from GO annotation data. We present a data mining approach, Multi-ontology data mining at All Levels (MOAL) that uses the structure and relationships of the GO to mine multi-ontology multi-level association rules. We introduce two interestingness measures: Multi-ontology Support (MOSupport) and Multi-ontology Confidence (MOConfidence) customized to evaluate multi-ontology multi-level association rules. We also describe a variety of post-processing strategies for pruning uninteresting rules. We use publicly available GO annotation data to demonstrate our methods with respect to two applications (1) the discovery of co-annotation suggestions and (2) the discovery of new cross-ontology relationships. PMID:23850840

Manda, Prashanti; McCarthy, Fiona; Bridges, Susan M

2013-10-01

251

A cascade multilevel inverter using a single DC source  

Microsoft Academic Search

A method is presented showing that a cascade multilevel inverter can be implemented using only a single DC power source and capacitors. A standard cascade multilevel inverter requires 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)

Zhong Du; L eon M. Tolbert; J. N. Chiasson; B. Ozpineci

2006-01-01

252

Macro-level gender equality and alcohol consumption: A multi-level analysis across U.S. States  

PubMed Central

Higher levels of womens alcohol consumption have long been attributed to increases in gender equality. However, only limited research examines the relationship between gender equality and alcohol consumption. This study examined associations between five measures of state-level gender equality and five alcohol consumption measures in the United States. Survey data regarding mens and womens alcohol consumption from the 2005 Behavioral Risk Factor Surveillance System were linked to state-level indicators of gender equality. Gender equality indicators included state-level womens socioeconomic status, gender equality in socioeconomic status, reproductive rights, policies relating to violence against women, and womens political participation. Alcohol consumption measures included past 30-day drinker status, drinking frequency, binge drinking, volume, and risky drinking. Other than drinker status, consumption is measured for drinkers only. Multi-level linear and logistic regression models adjusted for individual demographics as well as state-level income inequality, median income, and % Evangelical Protestant/Mormon. All gender equality indicators were positively associated with both womens and mens drinker status in models adjusting only for individual-level covariates; associations were not significant in models adjusting for other state-level characteristics. All other associations between gender equality and alcohol consumption were either negative or non-significant for both women and men in models adjusting for other state-level factors. Findings do not support the hypothesis that higher levels of gender equality are associated with higher levels of alcohol consumption by women or by men. In fact, most significant findings suggest that higher levels of equality are associated with less alcohol consumption overall. PMID:22521679

Roberts, Sarah C.M.

2014-01-01

253

Macro-level gender equality and alcohol consumption: a multi-level analysis across U.S. States.  

PubMed

Higher levels of women's alcohol consumption have long been attributed to increases in gender equality. However, only limited research examines the relationship between gender equality and alcohol consumption. This study examined associations between five measures of state-level gender equality and five alcohol consumption measures in the United States. Survey data regarding men's and women's alcohol consumption from the 2005 Behavioral Risk Factor Surveillance System were linked to state-level indicators of gender equality. Gender equality indicators included state-level women's socioeconomic status, gender equality in socioeconomic status, reproductive rights, policies relating to violence against women, and women's political participation. Alcohol consumption measures included past 30-day drinker status, drinking frequency, binge drinking, volume, and risky drinking. Other than drinker status, consumption is measured for drinkers only. Multi-level linear and logistic regression models adjusted for individual demographics as well as state-level income inequality, median income, and % Evangelical Protestant/Mormon. All gender equality indicators were positively associated with both women's and men's drinker status in models adjusting only for individual-level covariates; associations were not significant in models adjusting for other state-level characteristics. All other associations between gender equality and alcohol consumption were either negative or non-significant for both women and men in models adjusting for other state-level factors. Findings do not support the hypothesis that higher levels of gender equality are associated with higher levels of alcohol consumption by women or by men. In fact, most significant findings suggest that higher levels of equality are associated with less alcohol consumption overall. PMID:22521679

Roberts, Sarah C M

2012-07-01

254

Multi-level zero-inflated poisson regression modelling of correlated count data with excess zeros.  

PubMed

Count data with excess zeros relative to a Poisson distribution are common in many biomedical applications. A popular approach to the analysis of such data is to use a zero-inflated Poisson (ZIP) regression model. Often, because of the hierarchical study design or the data collection procedure, zero-inflation and lack of independence may occur simultaneously, which render the standard ZIP model inadequate. To account for the preponderance of zero counts and the inherent correlation of observations, a class of multi-level ZIP regression model with random effects is presented. Model fitting is facilitated using an expectation-maximization algorithm, whereas variance components are estimated via residual maximum likelihood estimating equations. A score test for zero-inflation is also presented. The multi-level ZIP model is then generalized to cope with a more complex correlation structure. Application to the analysis of correlated count data from a longitudinal infant feeding study illustrates the usefulness of the approach. PMID:16477948

Lee, Andy H; Wang, Kui; Scott, Jane A; Yau, Kelvin K W; McLachlan, Geoffrey J

2006-02-01

255

Rapid prototyping of multi-level polydimethylsiloxane-based microfluidic devices  

NASA Astrophysics Data System (ADS)

There has been considerable progress in the development of micro-fabricated systems for the field of chemical and biological sciences. Much development has been driven by the need of miniaturized systems that allow cost-effective and rapid processing of samples at the point of need. In this work, we investigate the application practicality of Objet Eden500VTMPolyjet as a rapid and economical tool for multi-level microfluidic device rapid prototyping. The Polyjet is a commercial system that utilizes ink-jet technology to print 3-dimensional structures with photopolymer materials. The reproducing capability of the Polyjet system in term of lateral and vertical resolutions, aspect ratio and smoothness of fabricated structures are investigated. In addition, the capability of the Polyjet is demonstrated by fabricating three different devices including: 1) multi-level microfluidic chip for two-step gene synthesis, 2) a fluidic component for micro/macro fluidic interfacing, and 3) PDMS-based microlens.

Cheong, Wai Chye; Kuan, Yoke Kong; Li, Mo-Huang; Ying, Jackie Y.

2008-12-01

256

Multi-level conduction in NiO resistive memory device prepared by solution route  

NASA Astrophysics Data System (ADS)

In this paper, we present nickel oxide (NiO) thin film bipolar non-volatile resistive memory device with multi-level conduction prepared by solution route at room temperature. The fabricated device with structure Al/NiO/ITO exhibits excellent switching parameters, such as a stable resistance value in both ON and OFF states for over 10?000 s (retention) and 105 switching cycles of memory operation (endurance). Stable multi-level conductance states are observed in the memory device, which could be exploited for a multilevel-cell programming scheme. The switching mechanism in the resistive memory device is discussed based on the formation/dissolution of conductive filaments.

Kannan, V.; Senthilkumar, V.; Rhee, J. K.

2013-03-01

257

Determination of the spin-dependent potentials with the multi-level algorithm  

E-print Network

The spin-dependent corrections to the static interquark potential are relevant to describing the fine and hyper-fine splittings of the heavy quarkonium spectra. We investigate these corrections in SU(3) lattice gauge theory with the Polyakov loop correlation function as the quark source by applying the multi-level algorithm. We observe remarkably clean signals for the spin-dependent potentials up to intermediate distances.

Koma, M; Wittig, H; Koma, Miho; Koma, Yoshiaki; Wittig, Hartmut

2005-01-01

258

MultiLevel Intervention to Prevent Influenza Infections in Older Low Income and Minority Adults  

Microsoft Academic Search

In this paper we describe a successful multi-level participatory intervention grounded in principles of individual and group\\u000a empowerment, and guided by social construction theory. The intervention addressed known and persistent inequities in influenza\\u000a vaccination among African American and Latino older adults, and associated infections, hospitalizations and mortality. It\\u000a was designed to increase resident ability to make informed decisions about vaccination,

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

2009-01-01

259

Inverter ratio failure detector  

NASA Technical Reports Server (NTRS)

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.

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

1974-01-01

260

Inverted Troughs Case Exercise  

NSDL National Science Digital Library

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.

Comet

2004-01-29

261

Cross-Ontology multi-level association rule mining in the Gene Ontology.  

PubMed

The Gene Ontology (GO) has become the internationally accepted standard for representing function, process, and location aspects of gene products. The wealth of GO annotation data provides a valuable source of implicit knowledge of relationships among these aspects. We describe a new method for association rule mining to discover implicit co-occurrence relationships across the GO sub-ontologies at multiple levels of abstraction. Prior work on association rule mining in the GO has concentrated on mining knowledge at a single level of abstraction and/or between terms from the same sub-ontology. We have developed a bottom-up generalization procedure called Cross-Ontology Data Mining-Level by Level (COLL) that takes into account the structure and semantics of the GO, generates generalized transactions from annotation data and mines interesting multi-level cross-ontology association rules. We applied our method on publicly available chicken and mouse GO annotation datasets and mined 5368 and 3959 multi-level cross ontology rules from the two datasets respectively. We show that our approach discovers more and higher quality association rules from the GO as evaluated by biologists in comparison to previously published methods. Biologically interesting rules discovered by our method reveal unknown and surprising knowledge about co-occurring GO terms. PMID:23071802

Manda, Prashanti; Ozkan, Seval; Wang, Hui; McCarthy, Fiona; Bridges, Susan M

2012-01-01

262

Grid Connected Photovoltaic (PV) Inverter with Robust Phase-Locked Loop (PLL)  

Microsoft Academic Search

An array of solar panels is connected to the mains through a three-phase active voltage-source inverter and a step-up transformer. The inverter synchronizes to the grid by means of a robust phase-locked loop (PLL), using input's quadrate method, and a multi-variable filter removes voltage harmonics caused by unbalance and distortion. The PWM active inverter utilizes a voltage oriented control (VOC)

T. Ostrem; W. Sulkowski; L. E. Norum; C. Wang

2006-01-01

263

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

SciTech Connect

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.

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

264

Role of Energy-Level Mismatches in a Multi-Pathway Complex of Photosynthesis  

E-print Network

Considering a multi-pathway structure in a light-harvesting complex of photosynthesis, we investigate the role of energy-level mismatches between antenna molecules in transferring the absorbed energy to a reaction center. We find a condition in which the antenna molecules faithfully play their roles: Their effective absorption ratios are larger than those of the receiver molecule directly coupled to the reaction center. In the absence of energy-level mismatches and dephasing noise, there arises quantum destructive interference between multiple paths that restricts the energy transfer. On the other hand, the destructive interference diminishes as asymmetrically biasing the energy-level mismatches and/or introducing quantum noise of dephasing for the antenna molecules, so that the transfer efficiency is greatly enhanced to near unity. Remarkably, the near-unity efficiency can be achieved at a wide range of asymmetric energy-level mismatches. Temporal characteristics are also optimized at the energy-level mismat...

Lim, James; Lee, Changhyoup; Yoo, Seokwon; Jeong, Hyunseok; Lee, Jinhyoung

2013-01-01

265

Multi-Level Determinants of Parasitic Fly Infection in Forest Passerines  

PubMed Central

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

Manzoli, Dario Ezequiel; Antoniazzi, Leandro Raul; Saravia, Maria Jose; Silvestri, Leonardo; Rorhmann, David; Beldomenico, Pablo Martin

2013-01-01

266

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

NASA Technical Reports Server (NTRS)

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.

Moon, Young J.; Liou, Meng-Sing

1989-01-01

267

IEEE TRANSACTIONS ON POWER ELECTRONICS 1 A Hybrid Power Control Concept for PV Inverters with Reduced  

E-print Network

IEEE TRANSACTIONS ON POWER ELECTRONICS 1 Letters A Hybrid Power Control Concept for PV Inverters- cept for grid-connected Photovoltaic (PV) inverters. The control strategy is based on either a Maximum utilization factor of PV inverters, and thus to cater for a higher penetration level of PV systems

Kerekes, Tamas

268

New control law for capacitor voltage balance in multilevel inverter with switching rate control (CVC)  

Microsoft Academic Search

A new control law for multilevel inverters is presented. It provides a fast and flexible control of the inverter capacitor voltages. It works for any number of cells any output voltage level. The inverter capacitor voltage control is completely independent from the load control, leading to a simpler implementation. The algorithm contains a tuning parameter for controlling the switching frequency

A. Donzel; G. Bornard

2000-01-01

269

Single-Phase Cascaded H-Bridge Multilevel Inverter with Nonactive Power Compensation  

E-print Network

Single-Phase Cascaded H-Bridge Multilevel Inverter with Nonactive Power Compensation for Grid presents a single-phase cascaded H- bridge multilevel inverter for a grid-connected photovoltaic (PV. A single-phase 11-level cascaded multilevel inverter is considered in both simulation and experimental

Tolbert, Leon M.

270

A General Space Vector PWM Algorithm for Multilevel Inverters, Including Operation in Overmodulation Range  

Microsoft Academic Search

This paper proposes a simple space vector pulsewidth modulation algorithm for a multilevel inverter for operation in the overmodulation range. The proposed scheme easily determines the location of the reference vector and calculates on-times. It uses a simple mapping to generate gating signals for the inverter. A five-level cascaded inverter is used to explain the scheme. The scheme can be

Amit Kumar Gupta; Ashwin M. Khambadkone

2007-01-01

271

Fundamental Frequency Modulated Multilevel Inverter for Three-Phase Stand-Alone  

E-print Network

Fundamental Frequency Modulated Multilevel Inverter for Three-Phase Stand-Alone Photovoltaic-6472, USA Abstract - This paper presents a fundamental frequency modulated multilevel inverter scheme connected PV arrays, a five-level diode-clamped multilevel inverter (DCMLI) generating fundamental

Tolbert, Leon M.

272

In situ multi-level analysis of viscoelastic deformation mechanisms in tendon collagen.  

PubMed

Tendon is a hydrated multi-level fibre composite, in which time-dependent behaviour is well established. Studies indicate significant stress relaxation, considered important for optimising tissue stiffness. However, whilst this behaviour is well documented, the mechanisms associated with the response are largely unknown. This study investigates the sub-structural mechanisms occurring during stress relaxation at both the macro (fibre) and nano (fibril) levels of the tendon hierarchy. Stress relaxation followed a two-stage exponential behaviour, during which structural changes were visible at the fibre and fibril levels. Fibril relaxation and fibre sliding showed a double exponential response, while fibre sliding was clearly the largest contributor to relaxation. The amount of stress relaxation and sub-structural reorganisation increased with increasing load increments, but fibre sliding was consistently the largest contributor to stress relaxation. A simple model of tendon viscoelasticity at the fibril and fibre levels has been developed, capturing this behaviour by serially coupling a Voigt element (collagen fibril), with two Maxwell elements (non-collagenous matrix between fibrils and fibres). This multi-level analysis provides a first step towards understanding how sub-structural interactions contribute to viscoelastic behaviour. It indicates that nano- and micro-scale shearing are significant dissipative mechanisms, and the kinetics of relaxation follows a two-stage exponential decay, well fitted by serially coupled viscoelastic elements. PMID:19822213

Gupta, H S; Seto, J; Krauss, S; Boesecke, P; Screen, H R C

2010-02-01

273

Grid connected DG systems based on Z-source NPC inverters  

Microsoft Academic Search

Z-source neutral-point-clamped (NPC) inverters have been recently presented as a buck-boost three-level inverter. In this paper five new grid-connected distributed generation (DG) systems are proposed using z-source NPC inverters. With the proposed systems, output power of two separate DG systems such as photovoltaic (PV) arrays and fuel cell (FC) stacks are extracted and delivered to the grid. Since NPC inverter

S. M. Dehghan; E. Seifi; M. Mohamadian; R Gharehkhani

2011-01-01

274

Pulsewidth-Modulated Z-Source Neutral-Point-Clamped Inverter  

Microsoft Academic Search

This paper presents the careful integration of a newly proposed Z-source topological concept to the basic neutral-point-clamped (NPC) inverter topology for designing a three-level inverter with both voltage-buck and voltage-boost capabilities. The designed Z-source NPC inverter uses two unique X-shaped inductance-capacitance (LC) impedance networks that are connected between two isolated dc input power sources and its inverter circuitry for boosting

Poh Chiang Loh; Feng Gao; Frede Blaabjerg; Shi Yun Charmaine Feng; Kong Ngai Jamies Soon

2007-01-01

275

Pulse-width modulated Z-source neutral-point-clamped inverter  

Microsoft Academic Search

This paper presents the careful integration of a newly proposed Z-source topological concept to the basic neutral-point-clamped (NPC) inverter topology, for designing a three-level inverter with both voltage-buck and -boost capabilities. The designed Z-source NPC inverter uses two unique X-shaped LC impedance networks connected between two isolated dc input power sources and its inverter circuitry for boosting its ac output

P. C. Loh; F. Blaabjerg; S. Y. Feng; K. N. Soon

2006-01-01

276

Nonlinear trends and multi-year cycles in regional and global sea level records  

NASA Astrophysics Data System (ADS)

We analyze the Permanent Service for Mean Sea Level (PSMSL) database of sea level time series using a method based on Monte Carlo Singular Spectrum Analysis (MC-SSA). We remove 2-30 year quasi- periodic oscillations and determine the nonlinear long-term trends for 12 large ocean regions. Our global sea level trend estimate of 2.4 1.0 mm/yr for the period from 1993 to 2000 is comparable with the 2.6 0.7 mm/yr sea level rise calculated from TOPEX/Poseidon altimeter measurements. However, we show that over the last 100 years the rate of 2.5 1.0 mm/yr occurred between 1920 and 1945, is likely to be as large as the 1990s, and resulted in a mean sea level rise of 48 mm. We evaluate errors in sea level using two independent approaches, the robust bi-weight mean and variance, and a novel "virtual station" approach that utilizes geographic locations of stations. Results suggest that a region cannot be adequately represented by a simple mean curve with standard error, assuming all stations are independent, as multi-year cycles within regions are very significant. Additionally, much of the between-region mismatch errors are due to multi-year cycles in the global sea level that limit the ability of simple means to capture sea level accurately. We demonstrate that variability in sea level records over periods 2-30 years has increased during the past 50 years in most ocean basins.

Moore, J. C.; Grinsted, A.; Jevrejeva, S.; Holgate, S.

2007-12-01

277

Read Current Instability Arising from Random Telegraph Noise in Localized Storage, MultiLevel SONOS Flash Memory  

Microsoft Academic Search

Program\\/erase cycling stress induced read current fluctuations arising from random telegraph noise (RTN) in a localized storage, multi-level nitride flash memory (SONOS) is explored. Our study shows that localized charge storage significantly enhances RTN. The amplitude of RTN varies in different program levels of a multi-level cell. The broadening of read current distribution due to RTN is characterized and modeled.

S. H. Gu; C. W. Li; Tahui Wang; W. P. Lu; K. C. Chen; J. Ku; Chih-Yuan Lu

2006-01-01

278

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

NASA Astrophysics Data System (ADS)

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.

Lachhwani, Kailash; Nehra, Suresh

2014-09-01

279

Multi-Core Parallel Simulation of System-Level Description Languages Rainer Domer, Weiwei Chen, Xu Han Andreas Gerstlauer  

E-print Network

and present a multi-core parallel simulation approach which au- tomatically protects communication between of heteroge- neous components, complex interconnect, sophisticated func- tionality, and slow simulationMulti-Core Parallel Simulation of System-Level Description Languages Rainer D¨omer, Weiwei Chen, Xu

Gerstlauer, Andreas

280

Multi-objective regionalisation for lake level simulation, the case of Lake Tana in the Upper Blue Nile, Ethiopia  

Microsoft Academic Search

The aim in this study is to simulate lake levels of Lake Tana by solving the water balance at daily time step. Since 42% of the basin is ungauged regionalisation procedures are applied. We examine the predictive capability of a regionalisation approach that combines multi-objective calibration of a simple conceptual model and multi regression analyses to establish relations between model

T. H. M. Rientjes; B. U. J. Perera; A. T. Haile; P. Reggiani

2010-01-01

281

Performance Enhancement of Embedded System Based Multilevel Inverter Using Genetic Algorithm  

NASA Astrophysics Data System (ADS)

This paper presents an optimal solution for eliminating pre specified order of harmonics from a stepped waveform of a multilevel inverter topology with equal dc sources. The main challenge of solving the associated non linear equation which are transcendental in nature and therefore have multiple solutions is the convergence of the relevant algorithms and therefore an initial point selected considerably close to the exact solution is required. The paper describes an efficient genetic algorithm that reduces significantly the computational burden resulting in fast convergence. An objective function describing a measure of effectiveness of eliminating selected order of harmonics while controlling the fundamental component is derived. The performance of cascaded multilevel inverter is compared based on computation of switching angle using Genetic Algorithm as well as conventional Newton Raphson approach. A significant improvement in harmonic profile is achieved in the GA based approach. A nine level cascaded multi level inverter is simulated in MATLAB Simulink and a proto type model has been fabricated to validate the simulation results.

Perumal, Maruthu Pandi; Nanjudapan, Devarajan

2011-07-01

282

Membrane fusion and inverted phases  

Microsoft Academic Search

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

Harma Ellens; David P. Siegel; Dennis Alford; Philip L. Yeagle; Lawrence Boni; Leonard J. Lis; Peter J. Quinn; Joe Bentz

1989-01-01

283

Multilevel DC-link inverter  

Microsoft Academic Search

This paper presents a new class of multilevel inverters based on a multilevel dc link (MLDCL) and a bridge inverter to reduce the number of switches, clamping diodes, or capacitors. An MLDCL can be a diode-clamped phase leg, a flying-capacitor phase leg, or cascaded half-bridge cells with each cell having its own dc source. A multilevel voltage-source inverter can be

Gui-Jia Su; Donald J. Adams

2005-01-01

284

Embedded EZ-Source Inverters  

Microsoft Academic Search

Z-source inverters are recent topological options proposed for buck-boost energy conversion with a number of possible voltage- and current-type circuitries already reported in the literature. Comparing them, a common feature noted is their inclusion of an LC impedance network, placed between the dc input source and inverter bridge. This impedance network allows the output end of a voltage-type Z-source inverter

Poh Chiang Loh; Feng Gao; Frede Blaabjerg

2010-01-01

285

Implications of multi-scale sea level and climate variability for coastal resources  

USGS Publications Warehouse

While secular changes in regional sea levels and their implications for coastal zone management have been studied extensively, less attention is being paid to natural fluctuations in sea levels, whose interaction with a higher mean level could have significant impacts on low-lying areas, such as wetlands. Here, the long record of sea level at Key West, FL is studied in terms of both the secular trend and the multi-scale sea level variations. This analysis is then used to explore implications for the Everglades National Park (ENP), which is recognized internationally for its ecological significance, and is the site of the largest wetland restoration project in the world. Very shallow topographic gradients (36 cm per km) make the region susceptible to small changes in sea level. Observations of surface water levels from a monitoring network within ENP exhibit both the long-term trends and the interannual-to-(multi)decadal variability that are observed in the Key West record. Water levels recorded at four long-term monitoring stations within ENP exhibit increasing trends approximately equal to or larger than the long-term trend at Key West. Time- and frequency-domain analyses highlight the potential influence of climate mechanisms, such as the El Nio/Southern Oscillation and the North Atlantic Oscillation (NAO), on Key West sea levels and marsh water levels, and the potential modulation of their influence by the background state of the North Atlantic Sea Surface Temperatures. In particular, the Key West sea levels are found to be positively correlated with the NAO index, while the two series exhibit high spectral power during the transition to a cold Atlantic Multidecadal Oscillation (AMO). The correlation between the Key West sea levels and the NINO3 Index reverses its sign in coincidence with a reversal of the AMO phase. Water levels in ENP are also influenced by precipitation and freshwater releases from the northern boundary of the Park. The analysis of both climate variability and climate change in such wetlands is needed to inform management practices in coastal wetland zones around the world.

Karamperidou, Christina; Engel, Victor; Lall, Upmanu; Stabenau, Erik; Smith, Thomas J.

2013-01-01

286

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

49 Transportation 4 2010-10-01 2010-10-01 false Example of a Multi-Level Car Complying with Window Location and Staggering Requirements-...a Multi-Level Car Complying with Window Location and Staggering...

2010-10-01

287

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

49 Transportation 4 2011-10-01 2011-10-01 false Example of a Multi-Level Car Complying with Window Location and Staggering Requirements-...a Multi-Level Car Complying with Window Location and Staggering...

2011-10-01

288

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

49 Transportation 4 2013-10-01 2013-10-01 false Example of a Multi-Level Car Complying with Window Location and Staggering Requirements-...a Multi-Level Car Complying with Window Location and Staggering...

2013-10-01

289

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

49 Transportation 4 2012-10-01 2012-10-01 false Example of a Multi-Level Car Complying with Window Location and Staggering Requirements-...a Multi-Level Car Complying with Window Location and Staggering...

2012-10-01

290

Monitoring Lake Level Variations in Yangtze River Basin Derived from Multi- Mission Satellite Altimetry  

NASA Astrophysics Data System (ADS)

Several satellite altimetry missions have been launched during the past decades and have demonstrated the accuracy level and the effectiveness of satellite altimetry as a technique to monitor water level variations of inland water bodies. The objective of the present study is to detect the water level fluctuations from a multi- mission approach for a better understanding of the behavior over long periods and obtain a better time resolution when overlaps exist, while trying to improve the accuracy improvement. We choose several major freshwater lakes located in the Yangtze River basin in China: Dongting Lake, Poyang Lake, Chao Lake, Hongze Lake and Taihu Lake. The altimetry data are obtained from the complete missions of Envisat, Topex and Jason-2. The timeseries of each target lake is achieved under the consideration of the error assessment between different missions.

Wu, Geli; Tourian, Mohammad; Sneeuw, Nico

2014-05-01

291

A multilevel PWM inverter topology for photovoltaic applications  

Microsoft Academic Search

A multilevel pulse-width modulated (PWM) single phase voltage-source inverter topology for photovoltaic applications is discussed in this paper. The use of the phase opposition (PO) carrier disposition multicarrier PWM switching technique for this topology is presented. Inverter switch control signals are derived. A 5-level and a 3-level PWM voltage waveform across the load is generated, for high and low modulation

V. G. Agelidis; D. M. Baker; W. B. Lawrance; C. V. Nayar

1997-01-01

292

Four quasi-Z-Source inverters  

Microsoft Academic Search

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

Joel Anderson; F. Z. Peng

2008-01-01

293

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

NASA Technical Reports Server (NTRS)

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.

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

1976-01-01

294

Glueball masses in 4d U(1) lattice gauge theory using the multi-level algorithm  

E-print Network

We take a new look at plaquette-plaquette correlators in 4d compact U(1) lattice gauge theory which are separated in time, both in the confined and the deconfined phases. From the behaviour of these correlators we extract glueball masses in the scalar as well as the axial-vector channels. Also in the deconfined phase, the non-zero momentum axial-vector correlator gives us information about the photon which appears as a massless particle in the spectrum. Using the Luescher - Weisz multi-level algorithm, we are able to go to large time separations which were not possible previously.

Majumdar, P; Koma, M; Majumdar, Pushan; Koma, Yoshiaki; Koma, Miho

2004-01-01

295

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

SciTech Connect

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.

Wanlass, M.

2012-05-01

296

Lossless Multiway Power Combining and Outphasing for High-Frequency Resonant Inverters  

E-print Network

A lossless multi-way power combining and outphasing system have recently been proposed for high-frequency inverters and power amplifiers that offers major performance advantages over traditional approaches. This paper ...

Roslaniec, Lukasz

297

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

Microsoft Academic Search

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

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

2004-01-01

298

MK4MDD: A Multi-Level Knowledge Base and Analysis Platform for Major Depressive Disorder  

PubMed Central

Background Major depressive disorder (MDD) is a complex neuropsychiatric syndrome with high heterogeneity. There are different levels of biological components that underlie MDD and interact with each other. To uncover the disease mechanism, large numbers of studies at different levels have been conducted. There is a growing need to integrate data from multiple levels of research into a database to provide a systematic review of current research results. The cross level integration will also help bridge gaps of different research levels for further understanding on MDD. So far, there has been no such effort for MDD. Descriptions We offer researchers a Multi-level Knowledge base for MDD (MK4MDD) to study the interesting interplay of components in the pathophysiological cascade of MDD from genetic variations to diagnostic syndrome. MK4MDD contains 2,341 components and 5,206 relationships between components based on reported experimental results obtained by diligent literature reading with manual curation. All components were well classified with careful curation and supplementary annotation. The powerful search and visualization tools make all data in MK4MDD form a cross-linked network to be applied to a broad range of both basic and applied research. Conclusions MK4MDD aims to provide researchers with a central knowledge base and analysis platform for MDD etiological and pathophysiological mechanisms research. MK4MDD is freely available at http://mdd.psych.ac.cn. PMID:23071556

Zhang, Liuyan; Ott, Jurg; Wang, Jing

2012-01-01

299

Optimization of inverted vector searches  

Microsoft Academic Search

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

Chris Buckley; Alan F. Lewit

1985-01-01

300

Multi-level Simulation of a Real Time Vibration Monitoring System Component  

NASA Technical Reports Server (NTRS)

This paper describes the development of a custom built Digital Signal Processing (DSP) printed circuit board designed to implement the Advanced Real Time Vibration Monitoring Subsystem proposed by MSFC Transportation Directorate in 2000 for the Space Shuttle Main Engine Advanced Health Management System (AHMS). This Real Time Vibration Monitoring System (RTVMS) is being developed for ground use as part of the AHMS Health Management Computer-Integrated Rack Assembly (HMC-IRA). The HMC-IRA RTVMS design contains five DSPs which are highly interconnected through individual communication ports, shared memory, and a unique communication router that allows all the DSPs to receive digitized data from two multi-channel analog boards simultaneously. This paper will briefly cover the overall board design but will focus primarily on the state-of-the-art simulation environment within which this board was developed. This 16-layer board with over 1800 components and an additional mezzanine card has been an extremely challenging design. Utilization of a Mentor Graphics simulation environment provided the unique board and system level simulation capability to ascertain any timing or functional concerns before production. By combining VHDL, Synopsys Software and Hardware Models, and the Mentor Design Capture Environment, multiple simulations were developed to verify the RTVMS design. This multi-level simulation allowed the designers to achieve complete operability without error the first time the RTVMS printed circuit board was powered. The HMCIRA design has completed all engineering unit testing and the deliverable unit is currently under development.

Roberston, Bryan; Wilkerson, DeLisa

2004-01-01

301

A Multi-level Solver for Gaussian Constrained Cosmic Microwave Background Realizations  

NASA Astrophysics Data System (ADS)

We present a multi-level solver for drawing constrained Gaussian realizations or finding the maximum likelihood estimate of the cosmic microwave background sky, given noisy sky maps with partial sky coverage. The method converges substantially faster than existing Conjugate Gradient (CG) methods for the same problem. For instance, for the 143 GHz Planck frequency channel, only three multi-level W-cycles result in an absolute error smaller than 1 ?K in any pixel. Using 16 CPU cores, this translates to a computational expense of 6 minutes wall time per realization, plus 8 minutes wall time for a power-spectrum-dependent precomputation. Each additional W-cycle reduces the error by more than an order of magnitude, at an additional computational cost of 2 minutes. For comparison, we have never been able to achieve similar absolute convergence with conventional CG methods for this high signal-to-noise data set, even after thousands of CG iterations and employing expensive preconditioners. The solver is part of the Commander 2 code, which is available with an open source license at http://commander.bitbucket.org/.

Seljebotn, D. S.; Mardal, K.-A.; Jewell, J. B.; Eriksen, H. K.; Bull, P.

2014-02-01

302

Multi-level interconnects for heterojunction bipolar transistor integrated circuit technologies  

SciTech Connect

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.

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

303

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

SciTech Connect

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.

Niski, K; Purnomo, B; Cohen, J

2006-11-06

304

Influence of multi-level impurities on the dynamics of ultrashort electromagnetic pulses in carbon nanotubes  

NASA Astrophysics Data System (ADS)

Based on Maxwell's equations, we study the propagation of an ultrashort electromagnetic pulse through an array of carbon nanotubes with multi-level impurities. The effective equation for the vector potential of the electromagnetic field is first derived analytically and then solved numerically. We subsequently analyze the dependence of the pulse shape on the parameters of the energy spectrum of impurities, and more precisely on the impurity levels. Our analysis predicts a significant decrease in the pulse amplitude during the transient, which is associated with the competitive effects of dispersion and other nonlinear effects. We also uncover the effects of the hopping integrals and band gap of deep impurities on the pulse tail decay.

Zhukov, Alexander V.; Bouffanais, Roland; Konobeeva, Natalia N.; Belonenko, Mikhail B.; George, Thomas F.

2014-05-01

305

Interevent time distributions of human multi-level activity in a virtual world  

E-print Network

Studying human behaviour in virtual environments provides extraordinary opportunities for a quantitative analysis of social phenomena with levels of accuracy that approach those of the natural sciences. In this paper we use records of player activities in the massive multiplayer online game Pardus over 1,238 consecutive days, and analyze dynamical features of sequences of actions of players. We build on previous work were temporal structures of human actions of the same type were quantified, and extend provide an empirical understanding of human actions of different types. This study of multi-level human activity can be seen as a dynamic counterpart of static multiplex network analysis. We show that the interevent time distributions of actions in the Pardus universe follow highly non-trivial distribution functions, from which we extract action-type specific characteristic "decay constants". We discuss characteristic features of interevent time distributions, including periodic patterns on different time scale...

Mryglod, Olesya; Szell, Michael; Holovatch, Yurij; Thurner, Stefan

2014-01-01

306

Health, policy and geography: insights from a multi-level modelling approach.  

PubMed

Improving the health and wellbeing of citizens ranks highly on the agenda of most governments. Policy action to enhance health and wellbeing can be targeted at a range of geographical levels and in England the focus has tended to shift away from the national level to smaller areas, such as communities and neighbourhoods. Our focus is to identify the potential for targeting policy interventions at the most appropriate geographical levels in order to enhance health and wellbeing. The rationale is that where variations in health and wellbeing indicators are larger, there may be greater potential for policy intervention targeted at that geographical level to have an impact on the outcomes of interest, compared with a strategy of targeting policy at those levels where relative variations are smaller. We use a multi-level regression approach to identify the degree of variation that exists in a set of health indicators at each level, taking account of the geographical hierarchical organisation of public sector organisations. We find that for each indicator, the proportion of total residual variance is greatest at smaller geographical areas. We also explore the variations in health indicators within a hierarchical level, but across the geographical areas for which public sector organisations are responsible. We show that it is feasible to identify a sub-set of organisations for which unexplained variation in health indicators is significantly greater relative to their counterparts. We demonstrate that adopting a geographical perspective to analyse the variation in indicators of health at different levels offers a potentially powerful analytical tool to signal where public sector organisations, faced increasingly with many competing demands, should target their policy efforts. This is relevant not only to the English context but also to other countries where responsibilities for health and wellbeing are being devolved to localities and communities. PMID:23849280

Castelli, Adriana; Jacobs, Rowena; Goddard, Maria; Smith, Peter C

2013-09-01

307

Health, policy and geography: Insights from a multi-level modelling approach?  

PubMed Central

Improving the health and wellbeing of citizens ranks highly on the agenda of most governments. Policy action to enhance health and wellbeing can be targeted at a range of geographical levels and in England the focus has tended to shift away from the national level to smaller areas, such as communities and neighbourhoods. Our focus is to identify the potential for targeting policy interventions at the most appropriate geographical levels in order to enhance health and wellbeing. The rationale is that where variations in health and wellbeing indicators are larger, there may be greater potential for policy intervention targeted at that geographical level to have an impact on the outcomes of interest, compared with a strategy of targeting policy at those levels where relative variations are smaller. We use a multi-level regression approach to identify the degree of variation that exists in a set of health indicators at each level, taking account of the geographical hierarchical organisation of public sector organisations. We find that for each indicator, the proportion of total residual variance is greatest at smaller geographical areas. We also explore the variations in health indicators within a hierarchical level, but across the geographical areas for which public sector organisations are responsible. We show that it is feasible to identify a sub-set of organisations for which unexplained variation in health indicators is significantly greater relative to their counterparts. We demonstrate that adopting a geographical perspective to analyse the variation in indicators of health at different levels offers a potentially powerful analytical tool to signal where public sector organisations, faced increasingly with many competing demands, should target their policy efforts. This is relevant not only to the English context but also to other countries where responsibilities for health and wellbeing are being devolved to localities and communities. PMID:23849280

Castelli, Adriana; Jacobs, Rowena; Goddard, Maria; Smith, Peter C.

2013-01-01

308

A study on the impact of high penetration distributed generation inverters on grid operation and stability  

NASA Astrophysics Data System (ADS)

Recent advances in inverter technology have enabled ancillary services such as volt/VAR regulation, SCADA communications, and active power filtering. Smart inverters can not only provide real power, but can be controlled to use excess capacity to provide reactive power compensation, power flow control, and active power filtering without supplementary inverter hardware. A transient level inverter model based on the Solectria 7700 inverter is developed and used to assess these control strategies using field data from an existing branch circuit containing two Amonix 68kW CPV-7700 systems installed at the University of California, Irvine.

Gu, Fei; Brouwer, Jack; Samuelsen, Scott

2013-09-01

309

Switched Inductor Z-Source Inverter  

Microsoft Academic Search

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

Miao Zhu; Kun Yu; Fang Lin Luo

2010-01-01

310

Role of Energy-Level Mismatches in a Multi-Pathway Complex of Photosynthesis  

E-print Network

Considering a multi-pathway structure in a light-harvesting complex of photosynthesis, we investigate the role of energy-level mismatches between antenna molecules in transferring the absorbed energy to a reaction center. We find a condition in which the antenna molecules faithfully play their roles: Their effective absorption ratios are larger than those of the receiver molecule directly coupled to the reaction center. In the absence of energy-level mismatches and dephasing noise, there arises quantum destructive interference between multiple paths that restricts the energy transfer. On the other hand, the destructive interference diminishes as asymmetrically biasing the energy-level mismatches and/or introducing quantum noise of dephasing for the antenna molecules, so that the transfer efficiency is greatly enhanced to near unity. Remarkably, the near-unity efficiency can be achieved at a wide range of asymmetric energy-level mismatches. Temporal characteristics are also optimized at the energy-level mismatches where the transfer efficiency is near unity. We discuss these effects, in particular, for the Fenna-Matthews-Olson complex.

James Lim; Junghee Ryu; Changhyoup Lee; Seokwon Yoo; Hyunseok Jeong; Jinhyoung Lee

2013-02-16

311

Role of energy-level mismatches in a multi-pathway complex of photosynthesis  

NASA Astrophysics Data System (ADS)

Considering a multi-pathway structure in a light-harvesting complex of photosynthesis, we investigated the role of energy-level mismatches between antenna molecules in transferring the absorbed energy to a reaction center (RC). We found a condition in which the antenna molecules faithfully play their roles: when their effective absorption ratios are larger than those of the receiver molecule directly coupled to the RC. In the absence of energy-level mismatches and dephasing noise, there arises quantum destructive interference between multiple paths that restricts the energy transfer. On the other hand, the destructive interference diminishes as asymmetrically biasing the energy-level mismatches and/or introducing quantum noise of dephasing for the antenna molecules, so that the transfer efficiency is greatly enhanced to nearly unity. Remarkably, the near-unity efficiency can be achieved at a wide range of asymmetric energy-level mismatches. Temporal characteristics are also optimized at the energy-level mismatches where the transfer efficiency is nearly unity. We discuss these effects, in particular, for the Fenna-Matthews-Olson complex.

Lim, James; Ryu, Junghee; Lee, Changhyoup; Yoo, Seokwon; Jeong, Hyunseok; Lee, Jinhyoung

2011-10-01

312

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

Multilevel Inverter Carrier-Based PWM Methods Leon M. Tolbert Thomas G. Habetler Oak Ridge National to optimize or balance the switch utilization in multilevel inverters. A 10 kW prototype six-level diode as a voltage source inverter. I. INTRODUCTION Multilevel pulse width modulation (PWM) inverters have been

Tolbert, Leon M.

313

Fine Structure of Optical Energy Levels Scheme for Ni{sup 2+} Doped in Inverted Perovskite BaLiF{sub 3}  

SciTech Connect

The aim of this paper is to calculate the fine structure of the optical energy levels scheme of BaLiF{sub 3}:Ni{sup 2+} taken into account besides the spin-orbit interaction, also the spin-spin, orbit-orbit and spin-other-orbit interactions. The numerical theoretical crystal field parameters were computed using the model exchange charge calculations of crystal field, taking into account the effects of the covalent bond formation between the Ni{sup 2+} and F{sup -} ions. The Hamiltonian of the BaLiF{sub 3}:Ni{sup 2+} system has been diagonalized in a complete basis set spanned by all wave functions of the 3d{sup 8} electron configuration. The comparison of the calculated energy levels with experimental data gives a satisfactory agreement, which confirms the model and used method.

Andreici, Emiliana-Laura [Department of Physics, West University of Timisoara, Bd. V. Parvan No. 4, 300223, Timisoara (Romania); Avram, N. M. [Department of Physics, West University of Timisoara, Bd. V. Parvan No. 4, 300223, Timisoara (Romania); Academy of Romanian Scientists, Independentei 54, 050094-Bucharest (Romania)

2011-10-03

314

Analysing the breakthrough of rock n roll (19301970) Multi-regime interaction and reconfiguration in the multi-level perspective  

Microsoft Academic Search

The breakthrough of rock n roll was part of broader transformations in the American music industry, involving changes in music instruments, music recording technology, audiences, radio programming and music styles. These transformations will be analysed as sociotechnical transition, using the multi-level perspective. One characteristic of the case is interactions between multiple regimes: radio and recording. Another characteristic is the presence

Frank W. Geels

2007-01-01

315

An inverter/controller subsystem optimized for photovoltaic applications  

NASA Technical Reports Server (NTRS)

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).

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

1978-01-01

316

Comparison between single- and multi-level patients: clinical and radiological outcomes 2 years after cervical disc replacement.  

PubMed

In cervical multi-level degenerative pathology, considering the morbidity of the extensive fusion techniques, some authors advocate for the multilevel disc replacement. This study compared the safety and efficacy of disc replacement with an unconstrained prosthesis in multi- versus single-level patients. A total of 231 patients with cervical degenerative disc disease (DDD) who were treated with cervical disc replacement and completed their 24 months follow-up were analyzed prospectively: 175 were treated at one level, 56 at 2 levels or more. Comparison between both groups was based on usual clinical and radiological outcomes [Neck Disability Index (NDI), Visual Analog Scale (VAS), Range of Motion, satisfaction]. Safety assessments, including complication and subsequent surgeries, were also documented and compared. Mean NDI and VAS scores for neck and arm pain were improved in both groups similarly. Improvement of mobility at treated segments was also similar. Nevertheless, in the multi-level group, analgesic use was significantly higher and occurrence of Heterotopic Ossification significantly lower than in the single-level group. Subject satisfaction was nearly equal, as 94.2% of single-level group patients would undergo the surgery again versus 94.5% in the multi-level group. The overall success rate did not differ significantly. Multi-level DDD is a challenging indication in the cervical spine. This study showed no major significant clinical difference between the two groups. We need further studies to know more about the impact of multi-level arthroplasty, especially on the adjacent segments, but these results demonstrate initial safety and effectiveness in this patient sample. PMID:21336970

Huppert, J; Beaurain, J; Steib, J P; Bernard, P; Dufour, T; Hovorka, I; Stecken, J; Dam-Hieu, P; Fuentes, J M; Vital, J M; Vila, T; Aubourg, L

2011-09-01

317

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

PubMed

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

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

2013-01-01

318

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

SciTech Connect

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.

Sniegowski, J.J.

1996-08-01

319

Multi-level analyses of spatial and temporal determinants for dengue infection  

PubMed Central

Background Dengue is a mosquito-borne viral infection that is now endemic in most tropical countries. In Thailand, dengue fever/dengue hemorrhagic fever is a leading cause of hospitalization and death among children. A longitudinal study among 1750 people in two rural and one urban sites in northern Thailand from 2001 to 2003 studied spatial and temporal determinants for recent dengue infection at three levels (time, individual and household). Methods Determinants for dengue infection were measured by questionnaire, land-cover maps and GIS. IgM antibodies against dengue were detected by ELISA. Three-level multi-level analysis was used to study the risk determinants of recent dengue infection. Results Rates of recent dengue infection varied substantially in time from 4 to 30%, peaking in 2002. Determinants for recent dengue infection differed per site. Spatial clustering was observed, demonstrating variation in local infection patterns. Most of the variation in recent dengue infection was explained at the time-period level. Location of a person and the environment around the house (including irrigated fields and orchards) were important determinants for recent dengue infection. Conclusion We showed the focal nature of asymptomatic dengue infections. The great variation of determinants for recent dengue infection in space and time should be taken into account when designing local dengue control programs. PMID:16420702

Vanwambeke, Sophie O; van Benthem, Birgit HB; Khantikul, Nardlada; Burghoorn-Maas, Chantal; Panart, Kamolwan; Oskam, Linda; Lambin, Eric F; Somboon, Pradya

2006-01-01

320

Multi-level trophic cascades in a heavily exploited open marine ecosystem.  

PubMed

Anthropogenic disturbances intertwined with climatic changes can have a large impact on the upper trophic levels of marine ecosystems, which may cascade down the food web. So far it has been difficult to demonstrate multi-level trophic cascades in pelagic marine environments. Using field data collected during a 33-year period, we show for the first time a four-level community-wide trophic cascade in the open Baltic Sea. The dramatic reduction of the cod (Gadus morhua) population directly affected its main prey, the zooplanktivorous sprat (Sprattus sprattus), and indirectly the summer biomass of zooplankton and phytoplankton (top-down processes). Bottom-up processes and climate-hydrological forces had a weaker influence on sprat and zooplankton, whereas phytoplankton variation was explained solely by top-down mechanisms. Our results suggest that in order to dampen the occasionally harmful algal blooms of the Baltic, effort should be addressed not only to control anthropogenic nutrient inputs but also to preserve structure and functioning of higher trophic levels. PMID:18460432

Casini, Michele; Lvgren, Johan; Hjelm, Joakim; Cardinale, Massimiliano; Molinero, Juan-Carlos; Kornilovs, Georgs

2008-08-01

321

Segmentation of hand radiographs by using multi-level connected active appearance models  

NASA Astrophysics Data System (ADS)

Robust and accurate segmentation methods are important for the computerized evaluation of medical images. For treatment of rheumatoid arthritis, joint damage assessment in radiographs of hands is frequently used for monitoring disease progression. Current clinical scoring methods are based on visual measurements that are time-consuming and subject to intra and inter-reader variance. A solution may be found in the development of partially automated assessment procedures. This requires reliable segmentation algorithms. Our work demonstrates a segmentation method based on multiple connected active appearance models (AAM) with multiple search steps using different quality levels. The quality level can be regulated by setting the image resolution and the number of landmarks in the AAMs. We performed experiments using two models of different quality levels for shape and texture information. Both models included AAMs for the carpal region, the metacarpals, and all phalanges. By starting an iterative search with the faster, low-quality model, we were able to determine the initial parameters of the second, high-quality model. After the second search, the results showed successful segmentation for 22 of 30 test images. For these images, 70% of the landmarks were found within 1.3 mm difference from manual placement by an expert. The multi-level search approach resulted in a reduction of 50% in calculation time compared to a search using a single model. Results are expected to improve when the model is refined by increasing the number of training examples and the resolution of the models.

Kauffman, Joost A.; Slump, Cornelis H.; Bernelot Moens, Hein J.

2005-04-01

322

The bidirectional Z-source inverter for energy storage application  

Microsoft Academic Search

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

Jacek Rabkowski

2007-01-01

323

Single-Phase Multilevel PWM Inverter Topologies Using Coupled Inductors  

Microsoft Academic Search

The number of voltage levels available in pulsewidth modulation (PWM) voltage source inverters can be increased by using a split-wound coupled inductor within each inverter leg and interleaved PWM switching of the upper and lower switches. The magnetizing inductance of the symmetrical split-wound inductor filters the high-frequency PWM voltage differences between the upper and lower switches. The same inductor presents

John Salmon; Andrew M. Knight; Jeffrey Ewanchuk

2009-01-01

324

PWM Inverters Using Split-Wound Coupled Inductors  

Microsoft Academic Search

The number of voltage levels available in PWM voltage source inverters can be increased by using an inverter leg with a split-wound coupled inductor and interleaved PWM switching of the upper and lower switches. The magnetizing inductance of the split-wound inductor filters the PWM-cycle instantaneous voltage differences between the upper and lower switches. The windings of the same inductor present

J. Salmon; J. Ewanchuk; A. Knight

2008-01-01

325

A hybrid multilevel inverter topology for drive applications  

Microsoft Academic Search

The use of multilevel inverters has become popular in recent years for high power applications. Various topologies and modulation strategies have been reported for utility and drive applications in the recent literature. This paper is devoted to the investigation of a 500 hp induction motor drive based on a seven-level 4.5 kV hybrid inverter. The topological structure and operating principles

Madhav D. Manjrekar; T.A. Lipo

1998-01-01

326

Multilevel inverter modulation schemes to eliminate common-mode voltages  

Microsoft Academic Search

It is well known that conventional two-level pulsewidth modulated (PWM) inverters generate high-frequency common-mode voltages with high dv\\/dt. Similarly, commonly used multilevel inverter modulation schemes generate common-mode voltages. Common-mode voltages may cause motor shaft voltages and bearing currents and conducted electromagnetic interference (EMI). Premature motor bearing failures and electronic equipment malfunctions have been reported to be directly related to bearing

Haoran Zhang; Annette von Jouanne; Shaoan Dai; Alan K. Wallace; Fei Wang

2000-01-01

327

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

NASA Technical Reports Server (NTRS)

A multi-level grid method has been 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 (e.g., 8 x 2 mesh cells) to fine (e.g., 128 x 32); the coarser grids are used to diminish the magnitude of the smooth part of the residuals, hopefully with far less total work than would be required with, say, optimal SLOR iterations on the finest grid. The method was applied to the solution of the transonic small-disturbance equation for the velocity potential in the conservation form. Nonlifting transonic flow past a parabolic-arc airfoil is the example studied, with meshes of both constant and variable step size.

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

1977-01-01

328

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

E-print Network

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...

Scafetta, Nicola

2013-01-01

329

[Hybrid operative interventions in patients with multi-level atherosclerotic lesions of lower-limb arteries].  

PubMed

The authors share their experience gained in hybrid surgical interventions for multi-level steno-occlusive lesions of the aortoiliac and infrainguinal segments in a total of 96 patients presenting with chronic ischaemia of the lower limbs. The postoperative-period complications included haematomas observed in 9 (9.4%) cases and 6 (6.3%) instances of lymphorrhea occurring in the area of the postoperative wound. There were no lethal outcomes in the immediate postoperative period. The remote results were assessed at follow-up terms varying from 6 to 53 months in 75 (79.7%) patients. Thrombosis of the bypass graft was registered in 6 cases and thrombosis of the stented iliac segment was encountered in 3 cases, which required amputation of the lower limb in 5 (6.7%) patients. PMID:24961327

Karpenko, A A; Starodubtsev, V B; Ignatenko, P V; Zoloev, D G

2014-01-01

330

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

NASA Astrophysics Data System (ADS)

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.

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

2014-05-01

331

High-Level Waste Tanks Multi-Dimensional Contaminant Transport Model Development  

SciTech Connect

A suite of multi-dimensional computer models was developed to analyze the transport of residual contamination from high-level waste tanks through the subsurface to seeplines. Cases analyzed ranged from all the tanks in the F- and H-tank farms for an overall look; to the Tank 17-20 4-pack to study plume interaction; to individual tanks, such as Tank 17 and 20 for comparison with one-dimensional and modeling. The main purpose of this work was to develop and test the models, so only two relatively conservative contaminants were examined, Tc-99 and I-129. More complex analyses, such as solubility-limited species and radionuclides that head a decay chain were not addressed in this study.

Collard, L.B.

1999-11-15

332

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

PubMed Central

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

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

2014-01-01

333

Ecological relevance of Sentinels' biomarker responses: a multi-level approach.  

PubMed

In response to the need for more sensitive and rapid indicators of environmental quality, sublethal effects on the lowest levels of biological organization have been investigated. The ecological relevance of these responses assumes a prevailing role to assure effectiveness as indicator of ecological status. This study aimed to investigate the linkages between biomarker responses of caged bivalves and descriptive parameters of macrobenthic community structure. For this purpose a multi-level environmental assessment of marine and estuarine zones was performed in So Paulo coast, Brazil. Multivariate analysis was applied to identify linkages between biological responses and ecological indices, as well as to characterizing the studied stations. Individuals of the marine mussel Perna perna caged along Santos Bay showed signs of oxidative stress, lysosomal membrane destabilization, histological alterations and reduced embryonic development. The estuarine oyster Crassostrea rhizophorae caged along Santos Port Channel showed alterations on biotransformation enzymes and antioxidant system, DNA damage and lysosomal membrane destabilization. The benthic community analysis showed reduced richness and diversity in the same areas of the Santos bay and estuary where biomarker responses were altered. Our results revealed that xenobiotics are inducing physiological stress, which may lead to changes of the benthic community structure and deterioration of the ecological status over time. Integrating biomarker responses and ecological indexes improved certainty that alterations found at community level could be related to xenobiotic as stressors, which was very useful to improve the discriminatory power of the environmental assessment. PMID:24314371

Seabra Pereira, Camilo D; Abessa, Denis M S; Choueri, Rodrigo B; Almagro-Pastor, Victor; Cesar, Augusto; Maranho, Luciane A; Martn-Daz, Mara Laura; Torres, Ronaldo J; Gusso-Choueri, Paloma K; Almeida, Joo E; Cortez, Fernando S; Mozeto, Antonio A; Silbiger, Helcy L N; Sousa, Eduinetty C P M; Del Valls, Tommas Angel; Bainy, Afonso C D

2014-05-01

334

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

NASA Astrophysics Data System (ADS)

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.

Gentile, Martin J.; Barnes, William L.

2014-09-01

335

Control of a hybrid asymmetric multilevel inverter for competitive medium-voltage industrial drives  

Microsoft Academic Search

In symmetric multilevel inverters, there is a tradeoff between the output quality and the reliability and efficiency of the converter. New asymmetric and hybrid solutions, using different voltages and devices in various parts of the inverter, promise significant improvements for medium-voltage industrial drives. This paper investigates such a hybrid asymmetric nine-level inverter. It consists of a three-phase three-level integrated gate-commutated

Martin Veenstra; Alfred Rufer

2005-01-01

336

Separating regional and global sea level contributions with an inverse multi-sensor approach  

NASA Astrophysics Data System (ADS)

We quantify the effect of mass flux (ice sheets, glaciers, land water storage) and steric changes on long-term and seasonal regional and global sea level variability. We perform a joint inversion with GRACE time-variable gravity and Jason-1/2 altimetric data and compare our results with those obtained with other methods. In this way, we are able to explain 1,45 mm/a of the 1,93 mm/a total sea level rise observed for 8/2002-7/2009. An inverse method to separate the temporal evolution of about 100 'fingerprints' of glacier and ice-sheet melting, thermal expansion, changes in catchment water storage and glacial isostatic adjustment from spaceborne gravity and altimetry data has been developed. Our method takes into account the effects of self-gravitation, elastic loading of the ocean bottom, and the response of Earth rotation to mass redistribution. For comparison, we also calculate the contributions of the individual catchments to sea level change from GRACE directly using a standard basin averaging method. While we find considerable differences between methods for catchment mass flux, GRACE-only results are quite robust in terms of global and regional sea level change. However, it turns out that adding Jason altimetry does provide valuable information in an inverse multi-sensor approach. In terms of global sea level rise, our results indicate, for example, a steric contribution of 0,35 mm/a in the considered time frame. Regionally, however, the contribution of ice sheets, glaciers, land water and steric changes displays strong variations. We will show results including error estimates for various regions.

Kusche, J.; Jensen, L.; Rietbroek, R.

2012-12-01

337

Overload protection system for power inverter  

Microsoft Academic Search

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

S. Nagano

1977-01-01

338

Extended-Boost Source Inverters  

Microsoft Academic Search

The Z-source inverter has gained popularity as a single-stage buck-boost inverter topology among many researchers. However, its boosting capability could be limited, and therefore, it may not be suitable for some applications requiring very high boost demand of cascading other dc-dc boost converters. This could lose the efficiency and demand more sensing for controlling the added new stages. This paper

C. J. Gajanayake; Fang Lin Luo; Hoay Beng Gooi; Ping Lam So; Lip Kian Siow

2010-01-01

339

On the utility of the multi-level algorithm for the solution of nearly completely decomposable Markov chains  

NASA Technical Reports Server (NTRS)

Recently the Multi-Level algorithm was introduced as a general purpose solver for the solution of steady state Markov chains. In this paper, we consider the performance of the Multi-Level algorithm for solving Nearly Completely Decomposable (NCD) Markov chains, for which special-purpose iteractive aggregation/disaggregation algorithms such as the Koury-McAllister-Stewart (KMS) method have been developed that can exploit the decomposability of the the Markov chain. We present experimental results indicating that the general-purpose Multi-Level algorithm is competitive, and can be significantly faster than the special-purpose KMS algorithm when Gauss-Seidel and Gaussian Elimination are used for solving the individual blocks.

Leutenegger, Scott T.; Horton, Graham

1994-01-01

340

Comparison of Traditional Inverters and Z Source Inverter for Fuel Cell Vehicles  

Microsoft Academic Search

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

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

2007-01-01

341

iqr: a tool for the construction of multi-level simulations of brain and behaviour.  

PubMed

The brain is the most complex system we know of. Despite the wealth of data available in neuroscience, our understanding of this system is still very limited. Here we argue that an essential component in our arsenal of methods to advance our understanding of the brain is the construction of artificial brain-like systems. In this way we can encompass the multi-level organisation of the brain and its role in the context of the complete embodied real-world and real-time perceiving and behaving system. Hence, on the one hand, we must be able to develop and validate theories of brains as closing the loop between perception and action, and on the other hand as interacting with the real world. Evidence is growing that one of the sources of the computational power of neuronal systems lies in the massive and specific connectivity, rather than the complexity of single elements. To meet these challenges-multiple levels of organisation, sophisticated connectivity, and the interaction of neuronal models with the real-world-we have developed a multi-level neuronal simulation environment, iqr. This framework deals with these requirements by directly transforming them into the core elements of the simulation environment itself. iqr provides a means to design complex neuronal models graphically, and to visualise and analyse their properties on-line. In iqr connectivity is defined in a flexible, yet compact way, and simulations run at a high speed, which allows the control of real-world devices-robots in the broader sense-in real-time. The architecture of iqr is modular, providing the possibility to write new neuron, and synapse types, and custom interfaces to other hardware systems. The code of iqr is publicly accessible under the GNU General Public License (GPL). iqr has been in use since 1996 and has been the core tool for a large number of studies ranging from detailed models of neuronal systems like the cerebral cortex, and the cerebellum, to robot based models of perception, cognition and action to large-scale real-world systems. In addition, iqr has been widely used over many years to introduce students to neuronal simulation and neuromorphic control. In this paper we outline the conceptual and methodological background of iqr and its design philosophy. Thereafter we present iqr's main features and computational properties. Finally, we describe a number of projects using iqr, singling out how iqr is used for building a "synthetic insect". PMID:20502987

Bernardet, Ulysses; Verschure, Paul F M J

2010-06-01

342

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

SciTech Connect

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.

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

2011-01-01

343

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

SciTech Connect

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 VCd, CuCd, and Cui 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.

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

2011-07-01

344

Time-dependent radiative transfer for multi-level atoms using accelerated Lambda iteration  

NASA Astrophysics Data System (ADS)

We present a general formalism for computing self-consistent, numerical solutions to the time-dependent radiative transfer equation in low-velocity, multi-level ions undergoing radiative interactions. Recent studies of time-dependent radiative transfer have focused on radiation hydrodynamic and magnetohydrodynamic effects without lines, or have solved time-independent equations for the radiation field simultaneously with time-dependent equations for the state of the medium. In this paper, we provide a fully time-dependent numerical solution to the radiative transfer and atomic rate equations for a medium irradiated by an external source of photons. We use accelerated Lambda iteration to achieve convergence of the radiation field and atomic states. We perform calculations for a three-level atomic model that illustrates important time-dependent effects. We demonstrate that our method provides an efficient, accurate solution to the time-dependent radiative transfer problem. Finally, we characterize astrophysical scenarios in which we expect our solutions to be important.

van Adelsberg, Matthew; Perna, Rosalba

2013-02-01

345

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

NASA Astrophysics Data System (ADS)

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.

Munaf, Alessandro; Haack, Jeffrey R.; Gamba, Irene M.; Magin, Thierry E.

2014-05-01

346

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

PubMed Central

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.

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

2014-01-01

347

Participatory System Science: Multi-Level Comprehension Through a Game-like Process  

NASA Astrophysics Data System (ADS)

Participatory System Science: Multi-Level Comprehension Through a Game-like Process We built a time-series game that permits the player to make water management decisions concerning the Skagit River (north-central Washington state) every five years for 60 years. This work was inspired by the integrative efforts of the Skagit Climate Science Consortium and the Climate Impacts Group at the University of Washington. Our principle guiding concepts have been - Construct a reasonable system description with -- wherever possible -- Events / Consequences rendered both visually and in terms of financial impact. - Base the system description on peer reviewed publications - Emphasize both connection and absence of connection between player Actions and subsequent Consequences in the catchment basin. Player choices center around dam flow levels and steps to mitigate negative impacts of sediment transport into the lower (populated) reaches of the Skagit River and into Puget Sound (levees, new dams, estuary restoration, etcetera). With this work we hope to explore scientific results in public awareness by engaging the game Player as a problem solver.

Fatland, D. R.; Kuntz, L.

2012-12-01

348

Personality, adrenal steroid hormones, and resilience in maltreated children: A multi-level perspective  

PubMed Central

In this multi-level investigation, resilience in adaptive functioning among maltreated and nonmaltreated low-income children (N = 677) was examined in relation to the regulation of two stress-responsive adrenal steroid hormones, cortisol and dehydroepiandosterone (DHEA), as well as the personality constructs of ego resiliency and ego control. Maltreatment status was not related to differences in average levels of morning or afternoon cortisol or DHEA. However, lower morning cortisol was related to higher resilient functioning, but only in nonmaltreated children. In contrast, among physically abused children, high morning cortisol was related to higher resilient functioning. Morning and afternoon DHEA was negatively related to resilient functioning. Although diurnal change in cortisol was not related to resilience, for DHEA, maltreated children with high resilience showed an atypical rise in DHEA from morning to afternoon. Morning and afternoon cortisol/DHEA ratios were positively related to resilient functioning, but did not interact with maltreatment status. Ego resiliency and ego control strongly differentiated maltreated and nonmaltreated children, and the personality variables were substantially predictive of resilience. When considered together, demonstrated effects of personality, cortisol, and DHEA maintained independent contributions in predicting resilience among high-risk youth. PMID:17705903

Cicchetti, Dante; Rogosch, Fred A.

2012-01-01

349

An improved carrierwave-based SVPWM method using phase voltage redundancies for generalized cascaded multilevel inverter topology  

Microsoft Academic Search

Carrierwave-based space vector pulse width modulation (SVPWM), which is considered as a highly 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

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

2000-01-01

350

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

Microsoft Academic Search

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

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

2003-01-01

351

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

NASA Astrophysics Data System (ADS)

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.

Baik, Chan-Wook; Young Ahn, Ho; Kim, Yongsung; Lee, Jooho; Hong, Seogwoo; Hee Choi, Jun; Kim, Sunil; Hun Lee, Sang; Yeon Jun, So; Yu, SeGi; Lawrence Ives, R.; Min Kim, Jong; Hwang, Sungwoo

2014-01-01

352

New type T-Source inverter  

Microsoft Academic Search

This paper presents different topologies of voltage inverters with alternative input LC networks. The basic topology is known in the literature as a Z-source inverter (ZSI). Alternative passive networks were named by the authors as T-sources. T-source inverter has fewer reactive components in comparison to conventional Z-source inverter. The most significant advantage of the T-source inverter (TSI) is its use

Ryszard Strzelecki; Marek Adamowicz; Natalia Strzelecka; Wieslaw Bury

2009-01-01

353

Multicarrier PWM strategies for multilevel inverters  

Microsoft Academic Search

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

Brendan Peter McGrath; Donald Grahame Holmes

2002-01-01

354

Desynchronization of Noisy Multi-cellular Clocks Underlies the Population-level Singularity Behavior of Mammalian Circadian Clock  

NASA Astrophysics Data System (ADS)

The singularity behavior of circadian clocks defined as the suppression of circadian oscillation by critical perturbation is one of the intriguing dynamical properties of circadian rhythms. Although the singularity behaviors have been observed in various organisms, its mechanism has not yet been elucidated, because the hierarchical structure of multi-cell-level circadian clocks exists behind the organism-level circadian rhythm. In vitro light-responsible circadian system is indispensable for extracting the underlying mechanism of the singularity behavior behind the hierarchical structure of multi-cell organisms. To obtain such in vitro system, we synthetically constructed light-responsible mammalian clock cells by exogenously introducing a photo-responsible receptor. By using this synthetic system and population-level high-throughput promoter activity assay, we found that a light pulse with critical timing and strength can induce population-level singularity behavior of the light-responsible mammalian clock cells. Subsequent single-cell measurement revealed that desynchronization of multi-cellular clocks underlies the population-level singularity. A mathematical model consistently explains our population-level and single-cell-level experimental data, and also demonstrates that the synchronization and desynchronization of cellular clocks is the underlying mechanism of population-level response of circadian clocks to external perturbation. In addition, our model suggests that fluctuation in single-cell-level behavior of the clock cells is the key determinant of the observable singularity behavior.

Kobayashi, Tetsuya J.; Ukai, Hideki; Ueda, Hiroki R.

2007-07-01

355

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

NASA Astrophysics Data System (ADS)

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.

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

2012-02-01

356

Social and socio-demographic neighborhood effects on adolescent alcohol use: a systematic review of multi-level studies.  

PubMed

There is growing interest in the role of the neighborhood environment on adolescent alcohol use. Multi-level designs are ideally suited to this investigation due to their ability to examine area-level effects over and above the effects due to neighborhood composition. To date, most research in this area has focused on the physical availability of alcohol in the neighborhood. We reviewed the multi-level evidence on neighborhood-level risk and protective factors which influence adolescent alcohol use, excluding studies which assessed the impact of neighborhood-level alcohol availability and advertising. Systematic searches in Medline, EMBASE, CINAHL Plus, PsycINFO, Sociological Abstracts and SCOPUS identified 23 studies, examining 11 different neighborhood-level exposures. The majority of studies found no associations with residential mobility, neighborhood disorder or crime, employment or job availability, neighborhood attitudes to drinking, social capital and collective efficacy. For studies examining neighborhood-level socio-economic disadvantage mixed results were found. High levels of both adult and adolescent alcohol use in the community appeared to be associated with alcohol use whilst protective effects were found for enforcement of liquor laws. Methodological limitations within studies were evident. The dearth of high-quality, multi-level studies indicate that further research is required to inform the development of multi-faceted place-based policy and preventative interventions to reduce adolescent alcohol use. Future studies should consider the neighborhood context from the outset of study design and identify the individual-level control variables to adequately isolate neighborhood effects. Inclusion of moderation and mediation analyses would greatly contribute towards the understanding of causal pathways of neighborhood effects. PMID:24937324

Jackson, Nicki; Denny, Simon; Ameratunga, Shanthi

2014-08-01

357

Small Area and Individual Level Predictors of Physical Activity in Urban Communities: A Multi-Level Study in Stoke on Trent, England  

PubMed Central

Reducing population physical inactivity has been declared a global public health priority. We report a detailed multi-level analysis of small area indices and individual factors as correlates of physical activity in deprived urban areas. Multi-level regression analysis was used to investigate environmental and individual correlates of physical activity. Nine individual factors were retained in the overall model, two related to individual intentions or beliefs, three to access to shops, work or fast food outlets and two to weather; age and gender being the other two. Four area level indices related to: traffic, road casualties, criminal damage and access to green space were important in explaining variation in physical activity. PMID:19440408

Cochrane, Thomas; Davey, Rachel C.; Gidlow, Chris; Smith, Graham R.; Fairburn, Jon; Armitage, Christopher J.; Stephansen, Hilde; Speight, Svetlana

2009-01-01

358

Inverting the quantum cloning of photons  

E-print Network

We propose an experiment where a photon is first cloned using stimulated parametric down-conversion, making many (imperfect) copies, and then the cloning transformation is inverted, regenerating the original photon while destroying the copies. Focusing on the case where the initial photon is entangled with another photon, we study the conditions under which entanglement can be proven in the final state. The proposed experiment would provide a clear demonstration that quantum information is preserved in phase-covariant quantum cloning. It would furthermore allow an experimental proof for micro-macro entanglement in the intermediate multi-photon state. Finally it might form the basis of a quantum detection technique for small differences in transmission (e.g. in low-contrast biological samples), whose sensitivity scales better with the number of photons used than a classical transmission measurement.

Raeisi, Sadegh; Simon, Christoph

2011-01-01

359

Pulse number control of electrical resistance for multi-level storage based on phase change  

NASA Astrophysics Data System (ADS)

Phase change nonvolatile memory devices composed of SeSbTe chalcogenide semiconductor thin film were fabricated. The resistivity of the SeSbTe system was investigated to apply to multi-level data storage. The chalcogenide semiconductor acts as a programmable resistor that has a large dynamic range. The resistance of the chalcogenide semiconductor can be set to intermediate resistances between the amorphous and crystalline states using electric pulses of a specified power, and it can be controlled by repetition of the electric pulses. The size of the memory cell used in this work is 200 nm thick with a contact area of 1 m diameter. The resistance of the chalcogenide semiconductor gradually varies from 41 k? to 840 ? within octal steps. The resistance of the chalcogenide semiconductor decreases with increasing number of applied pulses. The step-down characteristic of the resistance can be explained as the crystalline region of the active phase change region increases with increasing number of applied pulses. The extent of crystallization was also estimated by the overall resistivity of the active region of the memory cell.

Nakayama, K.; Takata, M.; Kasai, T.; Kitagawa, A.; Akita, J.

2007-09-01

360

Massive fungal biodiversity data re-annotation with multi-level clustering.  

PubMed

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

Vu, Duong; Szke, Szniszl; Wiwie, Christian; Baumbach, Jan; Cardinali, Gianluigi; Rttger, Richard; Robert, Vincent

2014-01-01

361

Opportunities in multi dimensional trace metal imaging: Taking copper associated disease research to the next level  

PubMed Central

Copper plays an important role in numerous biological processes across all living systems predominantly because of its versatile redox behavior. Cellular copper homeostasis is tightly regulated and disturbances lead to severe disorders such as Wilson disease (WD) and Menkes disease. Age related changes of copper metabolism have been implicated in other neurodegenerative disorders such as Alzheimers disease (AD). The role of copper in these diseases has been topic of mostly bioinorganic research efforts for more than a decade, metal-protein interactions have been characterized and cellular copper pathways have been described. Despite these efforts, crucial aspects of how copper is associated with AD, for example, is still only poorly understood. To take metal related disease research to the next level, emerging multi dimensional imaging techniques are now revealing the copper metallome as the basis to better understand disease mechanisms. This review will describe how recent advances in X-ray fluorescence microscopy and fluorescent copper probes have started to contribute to this field specifically WD and AD. It furthermore provides an overview of current developments and future applications in X-ray microscopic methodologies. PMID:23079951

Vogt, Stefan; Ralle, Martina

2012-01-01

362

Computing Multi-Level Clustered Alignments of Gene-Expression Time-Series  

PubMed Central

Identifying similarities and differences in expression patterns across multiple time series can provide a better understanding of the relationships among various normal biological and experimentally induced conditions such as chemical treatments or the effects induced by a gene knockout/ suppression. We consider the task of identifying sets of genes that have a high degree of similarity both in their (i) expression profiles within each condition, and (ii) changes in expression responses across conditions. Previously, we developed an approach for aligning time series that computes clustered alignments. In this approach, an alignment represents the correspondences between two gene expression time series. Portions of one of the time series may be compressed or stretched to maximize the similarities between the two series. A clustered alignment groups genes such that the genes within a cluster share a common alignment, but each cluster is aligned independently of the others. Unlike standard gene-expression clustering, which groups genes according to the similarity of their expression profiles, the clustered-alignment approach clusters together genes that have similar changes in expression responses across treatments. We have now extended the clustered alignment approach to produce multi-level clusterings that identify subsets of genes that have a high degree of similarity both in their (i) expression profiles within each treatment, and (ii) changes in expression responses across treatments.

Craven, Mark; Muganda-Rippchen, Deborah

2014-01-01

363

Massive fungal biodiversity data re-annotation with multi-level clustering  

PubMed Central

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

Vu, Duong; Szoke, Szaniszlo; Wiwie, Christian; Baumbach, Jan; Cardinali, Gianluigi; Rottger, Richard; Robert, Vincent

2014-01-01

364

A novel DC voltage regulation scheme for dual-inverter grid-connected photovoltaic plants  

Microsoft Academic Search

A multilevel power conversion scheme for three-phase grid-connected photovoltaic (PV) generation systems is considered in this paper. The scheme is based on two insulated strings of PV panels, each one feeding the dc bus of a standard two-level three-phase voltage source inverter (VSI). Inverters are connected to the grid by a three-phase transformer having open-end windings on inverters side. The

G. Grandi; D. Ostojic; D. Casadei

2009-01-01

365

String and module integrated inverters for single-phase grid connected photovoltaic systems - a review  

Microsoft Academic Search

This work presents an overview on recent developments and a summary of the state-of-the-art in inverter technology for single-phase grid connected photovoltaic (PV) systems. The information provided includes details on commercially available European string and module integrated PV inverters, their efficiency, price trends and market share. This review is given for inverters for a power level up to 6 kW.

J. M. A. Myrzik; M. Calais

2003-01-01

366

A power line conditioner using cascade multilevel inverters for distribution systems  

Microsoft Academic Search

In this paper, a power line conditioner using a cascade multilevel inverter is presented for voltage regulation, reactive power (VAr) compensation, and harmonic filtering. The cascade M-level inverter consists of (M-1)\\/2 H bridges, in which each bridge has its own separate DC source. This new inverter can: (1) generate almost sinusoidal waveform voltage with only one time switching per line

Fang Zheng Peng; John W. McKeever; Donald J. Adams

1998-01-01

367

A power line conditioner using cascade multilevel inverters for distribution systems  

Microsoft Academic Search

A power line conditioner (PLC) using a cascade multilevel inverter is presented for voltage regulation, reactive power (VAr) compensation and harmonic filtering in this paper. The cascade M-level inverter consists of (M-1)\\/2 H-bridges in which each bridge has its own separate DC source. This new inverter: (1) can generate almost an sinusoidal waveform voltage with only one time switching per

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

1997-01-01

368

Europeanization and multi?level governance: EU cohesion policy and pre?accession aid in Southeast Europe  

Microsoft Academic Search

This opening contribution provides the framework for discussion for the case studies that follow. It outlines the key concepts employed simple and compound polities, Europeanization and multi?level governance and explains the origins and development of EU cohesion policy and related pre?accession instruments. It concludes by summarizing the main themes and issues addressed in the subsequent contributions.

Ian Bache

2010-01-01

369

A Multi-level Analysis of Factors Associated with Urinary Incontinence in Korean Long-term Care Hospitals (LTCH)  

E-print Network

A descriptive cross-sectional secondary data analysis Variables Category High Risk Group Low Risk Group EstimateA Multi-level Analysis of Factors Associated with Urinary Incontinence in Korean Long-term Care / SE Odds ratio Estimate / SE Odds ratio Gender Male 7.97** 1.90

Wisconsin at Madison, University of

370

The Development of a Multi-Level Model for Crisis Preparedness and Intervention in the Greek Educational System  

ERIC Educational Resources Information Center

This article proposes a multi-level model for crisis preparedness and intervention in the Greek educational system. It presents: a) a brief overview of leading models of school crisis preparedness and intervention as well as cultural considerations for contextually relevant crisis response; b) a description of existing crisis intervention

Hatzichristiou, Chryse; Issari, Philia; Lykitsakou, Konstantina; Lampropoulou, Aikaterini; Dimitropoulou, Panayiota

2011-01-01

371

The Effect of Multi-Level Laminoplasty and Laminectomy on the Biomechanics of the Cervical Spine: a Finite Element Study  

PubMed Central

Laminectomy has been regarded as a standard treatment for multi-level cervical stenosis. Concern for complications such as kyphosis has limited the indication of multi-level laminectomy; hence it is often augmented with an instrumented fusion. Laminoplasty has emerged as a motion preserving alternative. The purpose of this study was to compare the multidirectional flexibility of the cervical spine in response to a plate-only open door laminoplasty, double door laminoplasty, and laminectomy using a computational model. A validated three-dimensional finite element model of a specimen-specific intact cervical spine (C2-T1) was modified to simulate each surgical procedure at levels C3-C6. An additional goal of this work was to compare the instrumented computational model to our multi-specimen experimental findings to ensure similar trends in response to the surgical procedures. Model predictions indicate that mobility was retained following open and double door laminoplasty with a 5.4% and 20% increase in flexion, respectively, compared to the intact state. Laminectomy resulted in 57% increase in flexion as compared to the intact state, creating a concern for eventual kyphosis - a known risk/complication of multi-level laminectomy in the absence of fusion. Increased disc stresses were observed at the altered and adjacent segments post-laminectomy in flexion. PMID:25328475

Kode, Swathi; Kallemeyn, Nicole A; Smucker, Joseph D; Fredericks, Douglas C; Grosland, Nicole M

2014-01-01

372

Interictal spikes, fast ripples and seizures in partial epilepsies: combining multi-level computational models with experimental data  

E-print Network

Interictal spikes, fast ripples and seizures in partial epilepsies: combining multi;36(2):2164-77" DOI : 10.1111/j.1460-9568.2012.08039.x #12;2 Abstract Epileptic seizures, epileptic spikes and high mass) and microscopic (detailed network of neurons). At each level, we show how spikes, seizures

Paris-Sud XI, Université de

373

Putting Poverty in Political Context: A Multi-Level Analysis of Adult Poverty across 18 Affluent Democracies  

ERIC Educational Resources Information Center

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

Brady, David; Fullerton, Andrew S.; Cross, Jennifer Moren

2009-01-01

374

Multi-Level Discourse Analysis in a Physics Teaching Methods Course from the Psychological Perspective of Activity Theory  

ERIC Educational Resources Information Center

In this paper, we present and apply a multi-level method for discourse analysis in science classrooms. This method is based on the structure of human activity (activity, actions, and operations) and it was applied to study a pre-service physics teacher methods course. We argue that such an approach, based on a cultural psychological perspective,

Vieira, Rodrigo Drumond; Kelly, Gregory J.

2014-01-01

375

Imaging the multi-level magma reservoir at Mt. Etna volcano (Italy)  

NASA Astrophysics Data System (ADS)

The continuous GPS network operating on Mt. Etna with its 36 stations is currently one of the largest worldwide. The aim of this network is the evaluation of volcanic hazard and the modelling of the active sources. In this paper, we propose an in-depth analysis and modelling of continuous GPS data collected at Mt. Etna from May 2008 to December 2010. The analyzed period has been divided into four different coherent phases: 1) 14 May 2008-02 August 2008 (deflation of the entire GPS network); 2) 02 August 2008-14 June 2009 (deflation of the summit area and inflation at lower heights); 3) 14 June 2009-21 May 2010 (inflation of the entire GPS network); 4) 21 May 2010-31 December 2010 (inflation at medium and low heights and end of the inflation in the summit area). Analytical models indicate a non-uniform deformation style revealing spaced sources acting at different time on different segments of a multi-level magma reservoir. The Etnean plumbing system imaged here is depicted as an elongated magma reservoir that extends from the volcano body downwards to about 6.5 km below sea level (b.s.l.), sloping slightly towards the North-West, with storage volumes located at about 6.5, 2.0 and 0.0 km (b.s.l.). The changes in position of the modelled pressure sources during the analyzed time intervals indicate that, throughout the 2008 eruptive period, the deformation field was mostly driven by the upward migration of magma. On the other hand, the pattern of deformation recorded after the end of the eruption strongly suggests a significant contribution of the magma overpressure generated by the gas boiling, thus outlining the importance of volatiles content in magma.

Aloisi, Marco; Mattia, Mario; Ferlito, Carmelo; Palano, Mimmo; Bruno, Valentina; Cannav, Flavio

2011-08-01

376

Optimised space vector switching sequences for multilevel inverters  

Microsoft Academic Search

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 carrier and space vector modulation strategies applied to diode clamped, cascaded N-level or hybrid multilevel

B. P. McGrath; D. G. Holmes; T.A. Lipo

2001-01-01

377

Optimized space vector switching sequences for multilevel inverters  

Microsoft Academic Search

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

Brendan Peter McGrath; Donald Grahame Holmes; Thomas Lipo

2003-01-01

378

Advanced Modular Inverter Technology Development  

SciTech Connect

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

Adam Szczepanek

2006-02-04

379

Groundwater Age in Multi-Level Water Quality Monitor Wells on California Central Valley Dairies  

NASA Astrophysics Data System (ADS)

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.

Esser, B. K.; Visser, A.; Hillegonds, D. J.; Singleton, M. J.; Moran, J. E.; Harter, T.

2011-12-01

380

Socioeconomic Status and the Health of Youth: A Multi-level, Multi-domain Approach to Conceptualizing Pathways  

PubMed Central

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 youths neighborhood environments altering family characteristics and youth psychosocial and behavioral profiles, thereby increasing youths 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 youths 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 youths long-term health trajectories is necessary for the creation and implementation of successful interventions and policies to ultimately reduce health disparities. PMID:22845752

Schreier, Hannah M. C.; Chen, Edith

2012-01-01

381

Enhancing K-12 Ocean Science Education Through Multi-level Partnership  

NASA Astrophysics Data System (ADS)

This paper highlights the results of long-term collaborations between the University of South Florida's College of Marine Science (CMS) and the Pinellas County school district (22nd largest nationally) to advance and improve K-12 Earth/Ocean science education. The 12-year mission of Education and Public Outreach (EPO) in the College of Marine Science has been to meaningfully integrate ocean science research and science learning to enhance K-12 education for teachers and students. Our interactive and interdisciplinary programs include research cruises, field trips, authentic research projects, satellite broadcasts, and web-based technologies. This paper will focus on two programs, the Oceanography Camp for Girls and Teachers and Project Oceanography. We will address impact of these programs, what works, the role and value of partnerships, sustainability and future initiatives. An especially critical aspect of EPO is partnerships. Our partners include people, scientific facilities, community, and donors. Financial partnerships provide sustainability and continuity. For example, private donors have built a series of endowments to support the Oceanography Camp for Girls currently valued at over \\$1 million. Given the recent shift in state and federal funding priorities, private funding is a vital element of successful EPO programs. To date, marine science EPO partnerships have included 34 state agencies, universities, private research laboratories, schools, and museums; 75 scientist, advanced graduate students and teachers as co-instructors; 4 television stations and 2 production companies; and over 2,000,000 participants in 7 countries. Multi-level partnerships are enhancing K-12 classrooms around the world with relevant ocean science content and resources to further science interests, ocean awareness, and informed decision making.

Greely, T. M.; Coble, P.; Betzer, P. R.

2003-12-01

382

IMPACT: a multi-level family and school intervention targeting obesity in urban youth.  

PubMed

IMPACT (Ideas Moving Parents and Adolescents to Change Together) is a 3-group randomized, multi-level trial comparing the efficacy of two distinct behavioral interventions and a control condition on body mass index (BMI) in middle school urban youth who are overweight/obese. Interventions include: (1) SystemCHANGE (SC), a promising new behavior change approach that focuses on system redesign of the family environment and daily routines; (2) HealthyCHANGE (HC), a cognitive-behavioral and Motivational Interviewing (MI)-consistent approach to behavior change that focuses on increasing intrinsic motivation, self-monitoring, goal setting, and problem solving; and (3) diet and physical education counseling (attention control). In addition, about half of the participants are enrolled in a K-8 public school that offers an innovative community-sponsored fitness program, augmented by study-supported navigators. In addition to the primary interventions effects, the study assesses the moderating effect of the school environment on BMI, blood pressure, cardiovascular risk factors, and quality of life. The sample consists of 360 children entering 6th grade from a large urban school district in the Midwest, identified through an existing BMI screening program. The intervention period is 36 months, and measures are obtained at baseline, 12, 24, and 36 months. Using intent-to-treat analyses across the 36-month intervention window, we hypothesize that both SC and HC will have a greater impact on BMI and other health outcomes compared to health education alone, and that the enriched school environment will enhance these effects. This manuscript describes IMPACT's study design and methods. PMID:24008055

Moore, Shirley M; Borawski, Elaine A; Cuttler, Leona; Ievers-Landis, Carolyn E; Love, Thomas E

2013-11-01

383

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

NASA Astrophysics Data System (ADS)

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.

Scafetta, N.

2013-04-01

384

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

NASA Astrophysics Data System (ADS)

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.

Scafetta, N.

2014-07-01

385

Family, Community and Clinic Collaboration to Treat Overweight and Obese Children: Stanford GOALS -- a Randomized Controlled Trial of a Three-Year, Multi-Component, Multi-Level, Multi-Setting Intervention  

PubMed Central

Objective To test the effects of a three-year, community-based, multi-component, multi-level, multi-setting (MMM) approach for treating overweight and obese children. Design Two-arm, parallel group, randomized controlled trial with measures at baseline, 12, 24, and 36 months after randomization. Participants Seven through eleven year old, overweight and obese children (BMI ? 85th percentile) and their parents/caregivers recruited from community locations in low-income, primarily Latino neighborhoods in Northern California. Interventions Families are randomized to the MMM intervention versus a community health education active-placebo comparison intervention. Interventions last for three years for each participant. The MMM intervention includes a community-based after school team sports program designed specifically for overweight and obese children, a home-based family intervention to reduce screen time, alter the home food/eating environment, and promote self-regulatory skills for eating and activity behavior change, and a primary care behavioral counseling intervention linked to the community and home interventions. The active-placebo comparison intervention includes semi-annual health education home visits, monthly health education newsletters for children and for parents/guardians, and a series of community-based health education events for families. Main Outcome Measure Body mass index trajectory over the three-year study. Secondary outcome measures include waist circumference, triceps skinfold thickness, accelerometer-measured physical activity, 24-hour dietary recalls, screen time and other sedentary behaviors, blood pressure, fasting lipids, glucose, insulin, hemoglobin A1c, C-reactive protein, alanine aminotransferase, and psychosocial measures. Conclusions The Stanford GOALS trial is testing the efficacy of a novel community-based multi-component, multi-level, multi-setting treatment for childhood overweight and obesity in low-income, Latino families. PMID:24028942

Robinson, Thomas N.; Matheson, Donna; Desai, Manisha; Wilson, Darrell M.; Weintraub, Dana L.; Haskell, William L.; McClain, Arianna; McClure, Samuel; Banda, Jorge; Sanders, Lee M.; Haydel, K. Farish; Killen, Joel D.

2013-01-01

386

RNA-Seq and molecular docking reveal multi-level pesticide resistance in the bed bug  

PubMed Central

Background Bed bugs (Cimex lectularius) are hematophagous nocturnal parasites of humans that have attained high impact status due to their worldwide resurgence. The sudden and rampant resurgence of C. lectularius has been attributed to numerous factors including frequent international travel, narrower pest management practices, and insecticide resistance. Results We performed a next-generation RNA sequencing (RNA-Seq) experiment to find differentially expressed genes between pesticide-resistant (PR) and pesticide-susceptible (PS) strains of C. lectularius. A reference transcriptome database of 51,492 expressed sequence tags (ESTs) was created by combining the databases derived from de novo assembled mRNA-Seq tags (30,404 ESTs) and our previous 454 pyrosequenced database (21,088 ESTs). The two-way GLMseq analysis revealed ~15,000 highly significant differentially expressed ESTs between the PR and PS strains. Among the top 5,000 differentially expressed ESTs, 109 putative defense genes (cuticular proteins, cytochrome P450s, antioxidant genes, ABC transporters, glutathione S-transferases, carboxylesterases and acetyl cholinesterase) involved in penetration resistance and metabolic resistance were identified. Tissue and development-specific expression of P450 CYP3 clan members showed high mRNA levels in the cuticle, Malpighian tubules, and midgut; and in early instar nymphs, respectively. Lastly, molecular modeling and docking of a candidate cytochrome P450 (CYP397A1V2) revealed the flexibility of the deduced protein to metabolize a broad range of insecticide substrates including DDT, deltamethrin, permethrin, and imidacloprid. Conclusions We developed significant molecular resources for C. lectularius putatively involved in metabolic resistance as well as those participating in other modes of insecticide resistance. RNA-Seq profiles of PR strains combined with tissue-specific profiles and molecular docking revealed multi-level insecticide resistance in C. lectularius. Future research that is targeted towards RNA interference (RNAi) on the identified metabolic targets such as cytochrome P450s and cuticular proteins could lay the foundation for a better understanding of the genetic basis of insecticide resistance in C. lectularius. PMID:22226239

2012-01-01

387

Plasmonic backscattering enhanced inverted photovoltaics  

Microsoft Academic Search

A plasmonic nanoparticle incorporated inverted organic photovoltaic structure was demonstrated where a monolayer of Ag nanoparticles acted as a wavelength selective reflector. Enhanced light harvesting via plasmonic backscattering into the photovoltaic absorber was observed, resulting in a two-fold improvement in the photocurrent and increased open-circuit voltage. Further, utilizing an optical spacer, the plasmonic backscattering was spectrally controlled, thereby modulating the

D. M. N. M. Dissanayake; B. Roberts; P.-C. Ku

2011-01-01

388

A triangular path inverting interferometer  

Microsoft Academic Search

A triangular path inverting interferometer is described with application to the study of thermal 'schlieren'. This is practically free of any vibration and coherence troubles, and possesses the unique feature that either differential or total shear may be obtained only with proper positioning of the object; once aligned, the optical components need not be disturbed further. This simple and stable

D. Chakrabarti; S. P. Basu; M. De

1977-01-01

389

Multi-level multi-domain algorithm implementation for two-dimensional multiscale particle in cell simulations  

NASA Astrophysics Data System (ADS)

There are a number of modeling challenges posed by space weather simulations. Most of them arise from the multiscale and multiphysics aspects of the problem. The multiple scales dramatically increase the requirements, in terms of computational resources, because of the need of performing large scale simulations with the proper small-scales resolution. Lately, several suggestions have been made to overcome this difficulty by using various refinement methods which consist in splitting the domain into regions of different resolutions separated by well defined interfaces. The multiphysics issues are generally treated in a similar way: interfaces separate the regions where different equations are solved. This paper presents an innovative approach based on the coexistence of several levels of description, which differ by their resolutions or, potentially, by their physics. Instead of interacting through interfaces, these levels are entirely simulated and are interlocked over the complete extension of the overlap area. This scheme has been applied to a parallelized, two-dimensional, Implicit Moment Method Particle in Cell code in order to investigate its multiscale description capabilities. Simulations of magnetic reconnection and plasma expansion in vacuum are presented and possible implementation options for this scheme on very large systems are also discussed.

Beck, A.; Innocenti, M. E.; Lapenta, G.; Markidis, S.

2014-08-01

390

A LOGICAL INVERTED TAXONOMY OF SORTING ALGORITHMS S.M. Merritt K.K. Lau  

E-print Network

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

Lau, Kung-Kiu

391

Comparative Evaluation of Pulsewidth Modulation Strategies for Z-Source Neutral-Point-Clamped Inverter  

Microsoft Academic Search

Z-source neutral-point-clamped (NPC) inverter has recently been proposed as an alternative three-level buck-boost power conversion solution with an improved output waveform quality. In principle, the designed Z-source inverter functions by selectively \\

Poh Chiang Loh; Frede Blaabjerg; Chow Pang Wong

2007-01-01

392

Improved partial response maximum likelihood method combining modulation code for signal waveform modulation multi-level disc  

NASA Astrophysics Data System (ADS)

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%.

Wang, He-Qun; Pei, Jing; Pan, Long-Fa

2014-10-01

393

Changes in nitrogen resorption traits of six temperate grassland species along a multi-level N addition gradient  

Microsoft Academic Search

Nitrogen (N) resorption from senescing leaves is an important mechanism of N conservation for terrestrial plant species, but\\u000a changes in N-resorption traits over wide-range and multi-level N addition gradients have not been well characterized. Here,\\u000a a 3-year N addition experiment was conducted to determine the effects of N addition on N resorption of six temperate grassland\\u000a species belonging to three

Ju-Ying Huang; Xiao-Guang Zhu; Zhi-You Yuan; Shi-Huan Song; Xin Li; Ling-Hao Li

2008-01-01

394

An integrated approach for climate-change impact analysis and adaptation planning under multi-level uncertainties. Part I: Methodology  

Microsoft Academic Search

In this study, a large-scale integrated modeling system (IMS) was developed for supporting climate-change impact analysis and adaptation planning under multi-level uncertainties. A number of methodologies were seamlessly incorporated within IMS, including fuzzy-interval inference method (FIIM), inexact energy model (IEM), and uncertainty analysis. The system could (i) encompass multiple technologies, energy resources, and sub-sectors, and climate change impact analysis into

Y. P. Cai; G. H. Huang; Q. Tan; Z. F. Yang

2011-01-01

395

Multi-residue method for detecting coccidiostats at carry-over level in feed by HPLCMS\\/MS  

Microsoft Academic Search

A multi-residue HPLCESIMS\\/MS method has been developed for the simultaneous extraction, detection and confirmation of the 11 coccidiostats referenced by Regulation 2009\\/8\\/EC (lasalocid sodium, narasin, salinomycin sodium, monensin sodium, semduramicin sodium, maduramicin ammonium alpha, robenidine hydrochloride, decoquinate, halofuginone hydrobromide, nicarbazin, and diclazuril) in feedstuffs at carry-over level. The sensitivity of the method allows quantification and confirmation for all coccidiostats below

Ph. Delahaut; G. Pierret; N. Ralet; M. Dubois; N. Gillard

2010-01-01

396

Minimizing End-to-End Interference in I/O Stacks Spanning Shared Multi-Level Buffer Caches  

ERIC Educational Resources Information Center

This thesis presents an end-to-end interference minimizing uniquely designed high performance I/O stack that spans multi-level shared buffer cache hierarchies accessing shared I/O servers to deliver a seamless high performance I/O stack. In this thesis, I show that I can build a superior I/O stack which minimizes the inter-application interference

Patrick, Christina M.

2011-01-01

397

Recording of MultiLevel Run-Length-Limited Modulation Signals on Compact Disc\\/Digital Versatile Disc Rewritable Discs  

Microsoft Academic Search

Multi-level (ML) recording technology increases the capacity of standard compact disc (CD) and digital versatile disc (DVD) rewritable systems with no change to the optical\\/mechanical unit. The feasibility of applying ternary run-length-limited (3L-RLL) modulation to recording\\/playback on standard CD\\/DVD phase change discs is discussed. The use of 3L-RLL modulation increases the recording density 50% relative to conventional binary RLL (2L-RLL)

Feng-Hsiang Lo; Ji-Wen Kuo; Nai-Heng Tseng; Jau-Jiu Ju; Dennis Howe

2004-01-01

398

The long range properties of the compact U(1) lattice gauge theory with the multi-level algorithm  

E-print Network

The 4D compact U(1) lattice gauge theory (LGT) in the confinement phase is studied with the multi-level algorithm. The static potential, force and flux-tube profile between two static charges are precisely measured from correlation functions involving the Polyakov loop. Universality of the coefficient of the 1/r correction to the static potential, known as the Luescher term, and the transversal width of the flux-tube profile are investigated.

Koma, Y; Majumdar, P

2003-01-01

399

The long range properties of the compact U(1) lattice gauge theory with the multi-level algorithm  

Microsoft Academic Search

The 4D compact U(1) lattice gauge theory (LGT) in the confinement phase is studied with the multi-level algorithm. The static potential, force and flux-tube profile between two static charges are precisely measured from correlation functions involving the Polyakov loop. Universality of the coefficient of the 1r correction to the static potential, known as the Lscher term, and the transversal width

Y. Koma; M. Koma; P. Majumdar

2004-01-01

400

Multi-level sexual selection: individual and family-level selection for mating success in a historical human population.  

PubMed

Precopulatory sexual selection is the association between fitness and traits associated with mate acquisition. Although sexual selection is generally recognized to be a powerful evolutionary force, most investigations are limited to characters belonging to individuals. A broader multilevel perspective acknowledges that individual fitness can be affected by aspects of mating success that are characters of groups, such as families. Parental mating success in polygynous or polyandrous human societies may exemplify traits under group-level sexual selection. Using fitness measures that account for age-structure, I measure multilevel selection for mate number over 55 years in a human population with declining rates of polygyny. Sexual selection had three components: individual-level selection for ever-mating (whether an individual mated) and individual- and family-level selection for polyandry and polygyny. Family- and individual-level selection for polygyny was equally strong, three times stronger than family-level selection for polyandry and more than an order of magnitude stronger than individual-level selection for polyandry. However, individual-level selection for polyandry and polygyny was more effective at explaining relative fitness variance than family-level selection. Selection for ever-mating was the most important source of sexual selection for fitness; variation for ever-mating explained 23% of relative fitness variance. PMID:23730758

Moorad, Jacob A

2013-06-01

401

OptCom: A Multi-Level Optimization Framework for the Metabolic Modeling and Analysis of Microbial Communities  

PubMed Central

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

Zomorrodi, Ali R.; Maranas, Costas D.

2012-01-01

402

Coupled Three-Phase Inductors for Interleaved Inverter Switching  

Microsoft Academic Search

This paper presents the use of coupled inductors to allow interleaved switching of the upper and lower switches of three-phase inverters. The approach increases the number of output voltage levels and reduces the magnitude of the output line currents at switching frequency. Two possible inductor topologies are investigated. Individual toriodal inductors for each phase are shown to provide more switching

Andrew M Knight; J. Ewanchuk; John C. Salmon

2008-01-01

403

A generalized design methodology for hybrid multilevel inverters  

Microsoft Academic Search

This paper develops a detailed analysis and proposes a generalized design methodology for hybrid multilevel inverters. With these hybrid topologies, it is possible to minimize the number of series-connected cells for a given number of levels, minimizing the THD of the output voltage and, therefore, reducing or even eliminating the output filter. With the proposed design methodology, the number of

Cassiano Rech; H. A. Grundling; Helio L. Hey; Humberto Pinheiro; J. R. Pinheiro

2002-01-01

404

Improved induction-heating inverter with power factor correction  

Microsoft Academic Search

An inverter aimed at induction heating applications is presented. It features power factor correction and fast response to sudden changes in the load, while providing the capability to vary the power supplied to the load. Power variation is achieved by means of pulse density modulation using variable-length sequences; thus allowing a high number of power levels to be achieved. The

Hugo Calleja; R. Ordonez

1999-01-01

405

High spatial resolution water level time series in the Florida Everglades wetlands using multi-track ALOS PALSAR data  

NASA Astrophysics Data System (ADS)

Wetland InSAR (Interferometric Synthetic Aperture Radar) observations provide very high-resolution maps of water level changes that cannot be obtained by any terrestrial technique. We recently developed the Small Temporal Baseline Subset (STBAS) approach, which combines single-track InSAR and stage (water level) observations to generate high-resolution absolute water level time series maps. However, the temporal resolution of produced time series is coarse compared with in-situ stage observation and, hence, the usefulness of these maps is rather limited. To compensate for the low temporal resolution weakness of space-based water level time series, we propose using a multi-track STBAS technique, which utilizes all available Synthetic Aperture Radar (SAR) observations acquired over a certain wetland area. We use a four-year long L-band ALOS PALSAR dataset acquired during 2007-2011 to test the proposed method over the Water Conservation Area 1 (WCA1) in the Everglades wetlands, south Florida (USA). A total of 37 images acquired with four tracks were collected. Daily water level data at 12 stage stations, which are monitored by the Everglades Depth Estimation Network (EDEN) in WCA1 area, were used to calibrate the InSAR-derived water level data. The proposed multi-track approach yielded a significant improvement of temporal resolution, which is dependent on the SAR satellite revisit cycle. Instead of the 46-day repeat orbit of ALOS, the multi-track method produces water level maps with temporal resolution of only 7 days. A quality control analysis of the methods indicates that the average root mean square error (RMSE) of the differences between stage water level and retrieved water level by InSAR technique is 4.0 cm. The end products of absolute water level time series with improved temporal and very high spatial resolutions can be used as excellent constraints for high-resolution wetland flow models. Furthermore, the next generation of SAR satellites has been designed with shorter revisit cycles, which will provide temporally denser maps of water level changes. Fig. 1. Comparison between stage (solid line) and InSAR (circle: 148 track, cross: 149 track, diamond: 464 track and square: 465 track) determined water level time series.

Hong, S.; Wdowinski, S.

2013-05-01

406

Fountain Codes and Invertible Matrices  

Microsoft Academic Search

This paper deals with Fountain codes, and especially with their encoding\\u000amatrices, which are required here to be invertible. A result is stated that an\\u000aencoding matrix induces a permutation. Also, a result is that encoding matrices\\u000aform a group with multiplication operation. An encoding is a transformation,\\u000awhich reduces the entropy of an initially high-entropy input vector. A special

Mikko Malinen

2009-01-01

407

Effective switching frequency multiplier inverter  

DOEpatents

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.

Su, Gui-Jia (Oak Ridge, TN); Peng, Fang Z. (Okemos, MI)

2007-08-07

408

Gripper deploying and inverting linkage  

DOEpatents

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.

Minichan, Richard L. (23 Pineview Dr., Warrenville, SC 29851); Killian, Mark A. (102 Foxhunt Dr., North Augusta, SC 29841)

1993-01-01

409

Gripper deploying and inverting linkage  

DOEpatents

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.

Minichan, R.L.; Killian, M.A.

1993-03-02

410

Multi-Level Factors Affecting Entry into and Engagement in the HIV Continuum of Care in Iringa, Tanzania  

PubMed Central

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

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

411

Multi-level factors affecting entry into and engagement in the HIV continuum of care in Iringa, Tanzania.  

PubMed

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

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

412

An empirical study of statistical properties of variance partition coefficients for multi-level logistic regression models  

USGS Publications Warehouse

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.

Li, J.; Gray, B.R.; Bates, D.M.

2008-01-01

413

IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS, VOL. 35, NO. 5, SEPTEMBER/OCTOBER 19991098 Novel Multilevel Inverter Carrier-Based PWM Method  

E-print Network

Multilevel Inverter Carrier-Based PWM Method Leon M. Tolbert, Senior Member, IEEE, and Thomas G. Habetler, Senior Member, IEEE Abstract The advent of the transformerless multilevel inverter topology has brought devices in each of the multiple voltage levels in the inverter. An analysis of how existing multilevel

Tolbert, Leon M.

414

Multi-party quantum private comparison protocol with n -level entangled states  

NASA Astrophysics Data System (ADS)

In this paper, two multi-party quantum private comparison (MQPC) protocols are proposed in distributed mode and traveling mode, respectively. Compared with the first MQPC protocol, which pays attention to compare between arbitrary two participants, our protocols focus on the comparison of equality for n participants with a more reasonable assumption of the third party. Through executing our protocols once, it is easy to get if n participants' secrets are same or not. In addition, our protocols are proved to be secure against the attacks from both outside attackers and dishonest participants.

Wang, Qing-Le; Sun, Hong-Xiang; Huang, Wei

2014-06-01

415

Continuum Level Formulation and Implementation of a Multi-scale Model for Vanadium  

SciTech Connect

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.

Lawrence Livermore National Laboratory

2009-08-17

416

Development of a dc-to-ac inverter based on waveshaping  

NASA Astrophysics Data System (ADS)

A new topology for utility interactive dc-ac inverters was explored. The approach is limited to the single phase, 2 to 10 kW power levels typical of residential photovoltaic applications. The approach combines two of the three basic inverter operations, waveshaping and regulation, in a single dc-dc converter stage. The output of this stage is a full wave rectified sine wave. An inversion stage follows, performing the third basic inverter operation. The output is a current sine wave. This approach features unity power factor and less than 2% total current harmonic distortion. A 1 kW prototype was constructed using a buck converter for the dc-dc stage switching at approximately 20 kHz. Efficiency was generally above 90%. A cost breakdown of the prototype indicates that the inverter can be built to meet the cost goals for this class of inverter.

Cox, C. H., III; Landsman, E. E.; Rasmussen, N. E.

1982-08-01

417

Fault protection in a multilevel inverter implementation of a static condenser  

SciTech Connect

Multilevel inverters are well suited for static condenser implementation in utility systems. With multilevel inverters, it is possible to realize low distortion voltage waveforms and keep losses low using suitable switching schemes. The complex topology of these inverters coupled with the large number of devices used increases the probability of device failure. In this paper, the fault modes of a multilevel inverter are investigated with special emphasis on the five level inverter. The main focus of the paper is on device failure and the corresponding impact on the operating conditions and resulting stresses. The presence of redundant states offers the possibility of continuing operation with inferior bus and device utilization following a fault. Failure of some devices is more critical than the failure of others, thereby emphasizing the need for adding redundant devices.

Sinha, G.; Hochgraf, C.; Lasseter, R.H.; Divan, D.M.; Lipo, T.A. [Univ. of Wisconsin, Madison, WI (United States)

1995-12-31

418

Facing the Challenge: Multi-Proficiency Levels in the Language Classroom.  

ERIC Educational Resources Information Center

Discusses the reasons for the differences in second language proficiency across Australia, including composite classes at primary and secondary levels and classes of mixed proficiency levels at secondary level. Reviews strategies for dealing with this problem, including effecting a smooth transition between primary and secondary schooling and the

Commins, Laura

1996-01-01

419

Multi-level Shared State for Distributed Systems DeQing Chen, Chunqiang Tang, Xiangchuan Chen,  

E-print Network

Weave represents a merger and extension of our previous Cashmere [19, 20] and InterAct [15] projects. Once shared- sors (level-1 sharing), Cashmere-style software distributed shared memory (S-DSM) within tightly of sharing at the lower (more tightly coupled) levels. At levels 1 and 2, InterWeave in- herits Cashmer

Scott, Michael L.

420

Multi-level Shared State for Distributed Systems DeQing Chen, Chunqiang Tang, Xiangchuan Chen,  

E-print Network

Weave represents a merger and extension of our previous Cashmere [19, 20] and InterAct [15] projects. Once shared- sors (level-1 sharing), Cashmere-style software distributed shared memory (S-DSM) within tightly at the lower (more tightly coupled) levels. At levels 1 and 2, InterWeave in- herits Cashmere's integrat

Dwarkadas, Sandhya

421

Multilevel Inverters for Electric Vehicle Applications  

SciTech Connect

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.

Habetler, T.G.; Peng, F.Z.; Tolbert, L.M.

1998-10-22

422

Perturbational treatment of spin-orbit coupling for generally applicable high-level multi-reference methods  

NASA Astrophysics Data System (ADS)

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.

Mai, Sebastian; Mller, Thomas; Plasser, Felix; Marquetand, Philipp; Lischka, Hans; Gonzlez, Leticia

2014-08-01

423

Improvement of the multi-level cell performance by a soft program method in flash memory devices  

NASA Astrophysics Data System (ADS)

A soft program method is proposed for charge-trap flash (CTF) memory devices. By adding a subsequent small positive gate pulse after main Fowler-Nordheim (FN) injection programming, early charge loss is greatly reduced. The multi-level cell performance as well as the initial flat-band voltage (VFB) instability can thereby be improved by removing the trapped electrons at the shallow traps in the blocking oxide layer. The proposed soft program method is a simple but very effective way to improve the fast retention property without changing the memory structure, especially for cases where the ?-value of the blocking oxide is high.

Park, Jong Kyung; Lee, Ki-Hong; Pyi, Seung Ho; Lee, Seok-Hee; Cho, Byung Jin

2014-04-01

424

Influence of Contextual Elements on Comprehensive Evaluations of Multi-Level Interventions: Lessons Learned and Promising Practices from Cases in Tobacco Control and Childhood Obesity  

E-print Network

Childhood Obesity By Jenica Huddleston ABSTRACT Influence ofto childhood obesity. Both of these elements could influenceinfluence the comprehensiveness of evaluating multi-level interventions within tobacco control and childhood

Huddleston, Jenica

2010-01-01

425

A Single-Phase Embedded Z-Source DC-AC Inverter  

PubMed Central

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

Kim, Se-Jin; Lim, Young-Cheol

2014-01-01

426

A single-phase embedded Z-source DC-AC inverter.  

PubMed

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

Kim, Se-Jin; Lim, Young-Cheol

2014-01-01

427

Multilevel inverters for electric vehicle applications  

Microsoft Academic Search

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

Leon M. Tolbert; Fang Z. Peng; Thomas G. Habetler

1998-01-01

428

Multilevel inverter by cascading industrial VSI  

Microsoft Academic Search

In this paper, the modularity concept applied to medium-voltage adjustable speed drives is addressed. First, the single-phase cascaded voltage-source inverter that uses series connection of insulated gate bipolar transistor (IGBT) H-bridge modules with isolated DC buses is presented. Next, a novel three-phase cascaded voltage-source inverter that uses three IGBT triphase inverter modules along with an output transformer to obtain a

Remus Teodorescu; Frede Blaabjerg; J. K. Pedersen; Ekrem Cengelci; Prasad N. Enjeti

2002-01-01

429

Inverted sparticle hierarchies from natural particle hierarchies  

SciTech Connect

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.

Aharony, O.; Berdichevsky, L.; Berkooz, M.; Hochberg, Y.; Robles-Llana, D. [Department of Particle Physics and Astrophysics, Weizmann Institute of Science, Rehovot 76100 (Israel)

2010-04-15

430

Multilevel NPC inverter for low-voltage applications  

Microsoft Academic Search

Multilevel inverter topologies are an alternative for a wide range of low voltage electrical drives. In the low voltage range (<1000 V) highly optimised switches with lower conduction and switching losses are available. For 550 V DC link voltage the power semiconductor losses of a two-level VSI with 1200 V-IGBT and a neutral-point-clamped three-level VSI in the power range between

Rudolf Mecke

2011-01-01

431

Fountain Codes and Invertible Matrices  

E-print Network

This paper deals with Fountain codes, and especially with their encoding matrices, which are required here to be invertible. A result is stated that an encoding matrix induces a permutation. Also, a result is that encoding matrices form a group with multiplication operation. An encoding is a transformation, which reduces the entropy of an initially high-entropy input vector. A special encoding matrix, with which the entropy reduction is more effective than with matrices created by the Ideal Soliton distribution is formed. Experimental results with entropy reduction are shown.

Malinen, Mikko

2009-01-01

432

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.

2009-11-23

433

Investigation of Fast Switched CMOS Inverter using  

E-print Network

Inverter is truly the nucleus of electronics industry. It is the main building block of everyday appliances i.e. microwaves, power tools, battery chargers, air conditioners and computers etc. In this paper, CMOS technology has been chosen to study the transient and dc characteristics of an inverter. Feature size is the main parameter to study the voltage transfer characteristics of inverter, for which length and width of transistors is varied. Further, CMOS inverters can be paralleled for increased power to drive higher current loads. Simulations are run on cadence design tool and the schematic diagrams are drawn in virtuoso schematic editor using 180nm technology file.

Navneet Kaur; Guru Nanak; Dev Engineering; Gurpurneet Kaur; Chahat Jain; Guru Nanak; Dev Engineering

434

A multi-level approach to community-focused training in drug education: part I working with parents, governors and school staff  

Microsoft Academic Search

Recent advice suggests that single-level, single-strand interventions are less effective in preventing or reducing harm from drug misuse than multi-level multi-agency approaches. This paper describes one aspect of a community-focused initiative in drug education. The overall aim of the initiative was to support and train key adults within the community to implement locally relevant schemes of work and drug-related policies.

Nick Boddington; David Perry; Ian Clements; Noreen Wetton; Jenny McWhirter

1999-01-01

435

A multi-level approach to community-focused training in drug education: part 2 teachers as researchers and partners in curriculum development  

Microsoft Academic Search

Recent advice suggests that single-level, single-strand interventions are less effective in preventing or reducing harm from drug misuse than multi-level multi-agency approaches. Part 1 described one aspect of a community focused initiative in drug education. The overall aim of the initiative was to support and train key adults within the community to implement locally relevant schemes of work and drug-related

Jenny McWhirter; Nick Boddington; David Perry; Ian Clements; Noreen Wetton

2000-01-01

436

The Writing Performance of Inverted and Non-inverted Right and Left-handers  

Microsoft Academic Search

The writing performance of inverted and non-inverted left-handed and right-handed writers was compared. Inverted writers wrote as quickly and as well as non-inverted writers when writing with the preferred writing posture, but were superior to the latter group when performances with the non-preferred posture were compared. There was no evidence that left-handers with either writing position write faster with the

Michael Peters; Jay McGrory

1987-01-01

437

DC Link Capacitor Voltage Balancing in a Three-Phase Diode Clamped Inverter Controlled by a Direct Space Vector of Line-to-Line Voltages  

Microsoft Academic Search

In this paper, the direct modulation strategy of a three-level inverter with self stabilization of the dc link voltage is extended to a five-level inverter. Therefore, a new modeling and control strategy of a five-level three-phase diode-clamped inverter (DCI) is presented. The obtained modeling shows that modulated multilevel voltages are obtained by combination of eight different three-level functions, which are

O. Bouhali; B. Francois; E. M. Berkouk; C. Saudemont

2007-01-01

438

Efficient multi-level fault simulation of HW\\/SW systems for structural faults  

Microsoft Academic Search

In recent technology nodes, reliability is increasingly considered a part of the standard design flow to be taken into account\\u000a at all levels of embedded systems design. While traditional fault simulation techniques based on low-level models at gate-\\u000a and register transfer-level offer high accuracy, they are too inefficient to properly cope with the complexity of modern embedded\\u000a systems. Moreover, they

Rafal Baranowski; Stefano Di Carlo; Nadereh Hatami; Michael E. Imhof; Michael A. Kochte; Paolo Prinetto; Hans-Joachim Wunderlich; Christian G. Zoellin

2011-01-01

439

Factors Affecting Public Prejudice and Social Distance on Mental Illness: Analysis of Contextual Effect by Multi-level Analysis  

PubMed Central

Objectives While there have been many quantitative studies on the public's attitude towards mental illnesses, it is hard to find quantitative study which focused on the contextual effect on the public's attitude. The purpose of this study was to identify factors that affect the public's beliefs and attitudes including contextual effects. Methods We analyzed survey on the public's beliefs and attitudes towards mental illness in Korea with multi-level analysis. We analyzed the public's beliefs and attitudes in terms of prejudice as an intermediate outcome and social distance as a final outcome. Then, we focused on the associations of factors, which were individual and regional socio-economic factors, familiarity, and knowledge based on the comparison of the intermediate and final outcomes. Results Prejudice was not explained by regional variables but was only correlated with individual factors. Prejudice increased with age and decreased by high education level. However, social distance controlling for prejudice increased in females, in people with a high education level, and in regions with a high education level and a high proportion of the old. Therefore, social distance without controlling for prejudice increased in females, in the elderly, in highly educated people, and in regions with a high education and aged community. Conclusions The result of the multi-level analysis for the regional variables suggests that social distance for mental illness are not only determined by individual factors but also influenced by the surroundings so that it could be tackled sufficiently with appropriate considering of the relevant regional context with individual characteristics. PMID:22509449

Jang, Hyeongap; Lim, Jun-Tae; Oh, Juhwan; Lee, Seon-Young; Kim, Yong-Ik

2012-01-01

440

INVERTED ECHO SOUNDER DEVELOPMENT G. F. Chaplin and D. Randolph Watts  

E-print Network

INVERTED ECHO SOUNDER DEVELOPMENT G. F. Chaplin and D. Randolph Watts Graduate School thermocline. Watts (1975), in discussing IES data from MODE I, showed that changes in dynamic height can evolving since its initial development. The first multi- instrument deployment was in MODE I (Watts

Rhode Island, University of

441

Multi-Level Kinetic Model Explaining Diverse Roles of Isozymes in Prokaryotes  

PubMed Central

Current standard methods for kinetic and genomic modeling cannot provide deep insight into metabolic regulation. Here, we developed and evaluated a multi-scale kinetic modeling approach applicable to any prokaryote. Specifically, we highlight the primary metabolism of the cyanobacterium Synechococcus elongatus PCC 7942. The model bridges metabolic data sets from cells grown at different CO2 conditions by integrating transcriptomic data and isozymes. Identification of the regulatory roles of isozymes allowed the calculation and explanation of the absolute metabolic concentration of 3-phosphoglycerate. To demonstrate that this method can characterize any isozyme, we determined the function of two glycolytic glyceraldehyde-3-phosphate dehydrogenases: one co-regulates high concentrations of the 3-phosphoglycerate, the other shifts the bifurcation point in hexose regulation, and both improve biomass production. Moreover, the regulatory roles of multiple phosphoglycolate phosphatases were defined for varying (non-steady) CO2 conditions, suggesting their protective role against toxic photorespiratory intermediates. PMID:25127487

Jablonsky, Jiri; Schwarz, Doreen; Hagemann, Martin

2014-01-01

442

A Class of Quasi-Z-Source Inverters  

Microsoft Academic Search

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

Joel Anderson; F. Z. Peng

2008-01-01

443

Solution processed, white emitting tandem organic light-emitting diodes with inverted device architecture.  

PubMed

Fully solution processed monochromatic and white-light emitting tandem or multi-photon polymer OLEDs with an inverted device architecture have been realized by employing WO3 /PEDOT:PSS/ZnO/PEI charge carrier generation layers. The luminance of the sub-OLEDs adds up in the stacked device indicating multi-photon emission. The white OLEDs exhibit a CRI of 75. PMID:24899163

Hfle, Stefan; Schienle, Alexander; Bernhard, Christoph; Bruns, Michael; Lemmer, Uli; Colsmann, Alexander

2014-08-13

444

Fitness inheritance in evolutionary and multi-objective high-level synthesis  

Microsoft Academic Search

The high-level synthesis process allows the auto- matic design and implementation of digital circuits starting from a behavioral description. Evolutionary algorithms are very widely adopted to approach this problem or just part of it. Neverthless, some concerns regarding execution times exist. In evolutionary high-level synthesis, design solutions have to be evaluated to extract information about some figures of merit (such

Christian Pilato; Gianluca Palermo; Antonino Tumeo; Fabrizio Ferrandi; Donatella Sciuto; Pier Luca Lanzi

2007-01-01

445

Practical Loop Transformations for Tensor Contraction Expressions on Multi-Level Memory Hierarchies  

SciTech Connect

Modern architectures are characterized by deeper levels of memory hierarchy, often explicitly addressable. Optimizing applications for such architectures requires careful management of the data movement across all these levels. In this paper, we focus on the problem of mapping tensor contractions to memory hierarchies with more than two levels, specifically addressing placement of memory allocation and data movement statements, choice of loop fusions, and tile size selection. Existing algorithms to find an integrated solution to this problem even for two-level memory hierarchies has been shown to be expensive. We improve upon this work by focusing on the first-order cost components, simplifying the analysis required and reducing the number of candidates to be evaluated. We have evaluated our framework on a cluster of GPUs. Using five tensor contraction expressions, we show that fusion at multiple levels improves performance, and our framework is effective in determining protable transformations.

Ma, Wenjing; Krishnamoorthy, Sriram; Agrawal, Gagan

2011-04-01

446

Multi-level signaling in the Stokes space and its application to large-capacity optical communications.  

PubMed

The Stokes vector of an optical signal does not depend on its absolute phase; therefore, we can construct the phase-insensitive optical communication system, using the Stokes vector as a modulation parameter. In such a system, multi-level optical signals can effectively be designed in the three-dimensional Stokes space and demodulated either by direct detection or by coherent detection, where low-complexity digital-signal processing (DSP) is employed. Although this system has the disadvantage that adaptive equalizers can hardly be implemented in the digital domain, it is still an attractive solution to large-capacity (? 100 Gbit/s) and medium-or short-reach (? 100 km) transmission. In this paper, we discuss the receiver configuration for the multi-level signal in the Stokes space and the efficient DSP algorithm for demodulating such a signal. Simulation results demonstrate that 2-, 4-, 8-, 16-, and 32-ary signals in the Stokes space have good bit-error rate (BER) characteristics. Especially, the 16-ary signal at the moderate symbol rate of 25 Gsymbol/s can reach the bit rate of 100 Gbit/s even by using direct detection. PMID:24718113

Kikuchi, Kazuro; Kawakami, Shojiro

2014-04-01

447

A Model of Adding Relations in Multi-levels to a Formal Organization Structure with Two Subordinates  

NASA Astrophysics Data System (ADS)

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}.

Sawada, Kiyoshi; Amano, Kazuyuki

2009-10-01

448

DC-Free Four-Ary (2,8) Run-Length Limited Code for Multi-level Recording Channels  

NASA Astrophysics Data System (ADS)

A new high efficient DC-free (2,8) run-length limited (RLL) code for four-level optical recording channels is proposed. The proposed code can be represented by a finite state diagram (FSM) with three states and implemented easily. The code rate and density ratio of the code are 5/6 bits/symbols and 2.50 bits/minimum-recorded-mark, respectively. On the basis of the experimental results, the performances of the code are evaluated by using partial-response maximum-likelihood (PRML) technology, which is suitable for detecting multi-level RLL signals. By using four-ary (2,8)RLL modulation and PRML technology, one can increase the recording density 66.7% relative to conventional binary RLL modulation currently used in digital versatile disc (DVD), meanwhile the bit error rate (BER) still be acceptable.

Hu, Heng; Pei, Jing; Xiong, Jianping; Ni, Yi; Pan, Longfa; Hu, Hua

2006-07-01

449

Coherent coupling and energy transfer enhancement via multi-exciton levels in semiconductor nanocrystals  

NASA Astrophysics Data System (ADS)

The theory of coherent energy transfer (ET) in nanocrystal (NC) systems [1] is generalized for multiexciton levels. The relevant excitonic states in an isolated NC can be described by an effective four-level system, consisting of the ground level, two degenerate single exciton levels, and the biexciton level. We study the dynamics of a single donor-acceptor pair via the equation of motion for the density matrix of the system and consider analytical limits as well as numerical solutions. We show that the enhancement of the ET efficiency introduced by the biexciton levels is limited due to the coherent coupling of the exciton-biexciton levels in the donor-acceptor pair. The saturation of the ET rate in the donor-acceptor pair suggests a new mechanism to control the dipole-dipole coupling strength in NC systems, and we present here its dependence on structure parameters. [1] A. N. Al-Ahmadi and S. E. Ulloa, Phys. Rev. B 70, 201302(R) (2004).

Al-Ahmadi, Ameenah; Ulloa, Sergio

2008-03-01

450

Employment, Crime, and Context: A Multi-Level Analysis of the Relationship between Work and Crime.  

National Technical Information Service (NTIS)

This dissertation examines the influence of work on criminal behavior. It stems from the perspective that work, at both the individual and community level, can shape attitudes, influence behavior and structure lifestyles. In this research, I examine wheth...

T. P. Wadsworth

2002-01-01

451

Organizational justice and mental health: a multi-level test of justice interactions.  

PubMed

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

Fischer, Ronald; Abubakar, Amina; Arasa, Josephine Nyaboke

2014-04-01

452

Sensory evaluation of the odors produced during bromophenol formation using a multi-level statistical model.  

PubMed

In response to reports of medicinal taste and odor problems in suburban Paris, a lab scale study was conducted to investigate the contribution of different water quality parameters--pH, phenol, bromide, chlorine, temperature and dissolved oxygen levels--on bromophenol medicinal odor formation using the Flavor Profile Analysis (FPA) method. A study of six parameters at 2 levels (64 experiments) analyzed by the FPA method suggests that chlorine at high concentration is more important as a controlling agent than phenol under similar conditions and the ratio of HOBr:Phenol and the time for reaction will control subsequent brominated products of reaction. Results from a three-level statistical model indicate that high pH was associated with lower odor intensities, whereas high levels of chlorine, phenol and temperature were associated with high odor intensities. Potential worst case scenarios of water quality conditions were determined for evaluation by chemical identification and kinetics. PMID:15237631

Al-Samarrai, H; Matud, J; Wiesenthal, K; Atiyah, P; Bruchet, A; Suffet, I H

2004-01-01

453

Combining Low-Level and Summary Representations of Opinions for Multi-Perspective Question Answering  

E-print Network

to a prespecified topic or domain of interest: it finds useful in- formation about the domain and encodes typically operate by identifying low-level "template relations" throughout the text (e.g. that a "tornado

Wiebe, Janyce M.

454

Probing Single- to Multi-Cell Level Charge Transport in Geobacter sulfurreducens DL-1.  

National Technical Information Service (NTIS)

Microbial fuel cells, in which living microorganisms convert chemical energy into electricity, represent a potentially sustainable energy technology for the future. Here we report the single-bacterium level current measurements of Geobacter sulfurreducens...

C. S. Jackan, E. R. Petersen, J. Hu L. A. Fitzgerald, X. Jiang

2013-01-01

455

A MultiLevel Approach to Investigating Neighborhood Effects on Physical Aggression among Urban Chicago Youth  

Microsoft Academic Search

The current study evaluates neighborhood effects, individual-level effects, and demographic characteristics that influence\\u000a physically aggressive behavior among urban youth. Using data derived from 5,812 adolescents from Project Northland Chicago\\u000a (PNC) and Heirarchical Linear Modeling (HLM) techniques, the results suggested that neighborhood problems significantly predicted\\u000a physical aggression, before and after adjustment for individual-level risk factors (alcohol use, peer alcohol use, lack

Wesley G. Jennings; Mildred M. Maldonado-Molina; Jennifer M. Reingle; Kelli A. Komro

456

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

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...

Parks, Kathrin Ann

2004-09-30

457

Multi-level, cross-sectional study of workplace social capital and smoking among Japanese employees  

PubMed Central

Background Social capital is hypothesized to be relevant to health promotion, and the association between community social capital and cigarette smoking has been examined. Individual-level social capital has been found to be associated with smoking cessation, but evidence remains sparse on the contextual effect of social capital and smoking. Further, evidence remains sparse on the association between smoking and social capital in the workplace, where people are spending an increasing portion of their daily lives. We examined the association between workplace social capital and smoking status among Japanese private sector employees. Methods We employed a two-stage stratified random sampling procedure. Of the total of 1,800 subjects in 60 companies, 1,171 (men/women; 834/337) employees (65.1%) were identified from 46 companies in Okayama in 2007. Workplace social capital was assessed in two dimensions; trust and reciprocity. Company-level social capital was based on inquiring about employee perceptions of trust and reciprocity among co-workers, and then aggregating their responses in order to calculate the proportion of workers reporting mistrust and lack of reciprocity. Multilevel logistic regression analysis was conducted using Markov Chain Monte Carlo methods to explore whether individual- and company-level social capital was associated with smoking. Odds ratios (ORs) and 95% credible intervals (CIs) for current smoking were obtained. Results Overall, 33.3% of the subjects smoked currently. There was no relationship between individual-level mistrust of others and smoking status. By contrast, one-standard deviation change in company-level mistrust was associated with higher odds of smoking (OR: 1.25, 95% CI: 1.06-1.46) even after controlling for individual-level mistrust, sex, age, occupation, educational attainment, alcohol use, physical activity, body mass index, and chronic diseases. No clear associations were found between lack of reciprocity and smoking both at the individual- and company-level. Conclusions Company-level mistrust is associated with higher likelihood of smoking among Japanese employees, while individual perceptions of mistrust were not associated. The link between lack of reciprocity and smoking was not supported either at the individual- or company-level. Further studies are warranted to examine the possible link between company-level trust and smoking cessation in the Japanese workplace. PMID:20716334

2010-01-01

458

Fractal multi-level organisation of human groups in a virtual world  

PubMed Central

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. PMID:25283998

Fuchs, Benedikt; Sornette, Didier; Thurner, Stefan

2014-01-01

459

Fractal multi-level organisation of human groups in a virtual world  

NASA Astrophysics Data System (ADS)

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.

Fuchs, Benedikt; Sornette, Didier; Thurner, Stefan

2014-10-01

460

Fractal multi-level organisation of human groups in a virtual world.  

PubMed

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. PMID:25283998

Fuchs, Benedikt; Sornette, Didier; Thurner, Stefan

2014-01-01

461

Interactive alignment and image reconstruction for wafer-level multi-aperture camera systems  

NASA Astrophysics Data System (ADS)

Assembly of miniaturized high-resolution cameras is typically carried out by active alignment. The sensor image is constantly monitored while the lens stack is adjusted. When sharpness is acceptable in all regions of the image, the lens position over the sensor is fixed. For multi-aperture cameras, this approach is not sufficient. During prototyping, it is beneficial to see the complete reconstructed image, assembled from all optical channels. However, typical reconstruction algorithms are high-quality offline methods that require calibration. As the geometric setup of the camera repeatedly changes during assembly, this would require frequent re-calibration. We present a real-time algorithm for an interactive preview of the reconstructed image during camera alignment. With this algorithm, systematic alignment errors can be tracked and corrected during assembly. Known imperfections of optical components can also be included in the reconstruction. Finally, the algorithm easily maps to very simple GPU operations, making it ideal for applications in mobile devices where power consumption is critical.

Oberdrster, Alexander; Brckner, Andreas; Lensch, Hendrik P. A.

2014-09-01

462

Inferring Ancestral Chloroplast Genomes with Inverted Repeat  

E-print Network

Inferring Ancestral Chloroplast Genomes with Inverted Repeat Liying Cui # , Feng Yue + , Claude W Chloroplast genomes, the in­ ference of inverted repeats is needed in ancestral genome reconstruction. We apply GRAPPA­IR to reconstruct an­ cestral chloroplast genomes containing duplicated genes. A test

Tang, Jijun

463

Inverted Soap Bubbles-A Surface Phenomenon  

Microsoft Academic Search

By pouring soap water onto a surface of soap water it is possible to produce thin spherical shells of air in the water (inverted soap bubbles). The largest diameter observed is about 20 mm. Interference colors indicate shell thickness of the order 0.001 mm. Lifetimes of the bubbles of 4-5 minutes have been observed. A connection between the inverted bubbles

N. Skogen

1956-01-01

464

Generalized Structure of a Multilevel PWM Inverter  

Microsoft Academic Search

A generalized structure of a multilevel voltage source thyristor inverter is proposed. The multilevel concept is used to decrease the harmonic distortion in the output waveform without decreasing the inverter power output. A simple uniform PWM control of the output voltage is seen to be sufficient to practically remove all remaining harmonics. Harmonic analysis of n-step waveform is given, and

Pradeep M. Bhagwat; V. R. Stefanovic

1983-01-01

465

An Adaptive photovoltaic-inverter topology  

Microsoft Academic Search

a new inverter topology for Adaptive photovoltaic (PV) system is proposed. An improvement in the power generation of the system during different operating conditions is achieved. The proposed configuration provides flexible connection between the PV modules and the inverters to meet current conditions of PV array. Preliminary simulation results are provided for an adaptive PV array. Efficiency comparison between traditional

Mahmoud. Alahmad; Mohamed Amer Chaaban; Siu Kit Lau

2011-01-01

466

The evolutionary impact of androgen levels on prostate cancer in a multi-scale mathematical model  

PubMed Central

Background Androgens bind to the androgen receptor (AR) in prostate cells and are essential survival factors for healthy prostate epithelium. Most untreated prostate cancers retain some dependence upon the AR and respond, at least transiently, to androgen ablation therapy. However, the relationship between endogenous androgen levels and cancer etiology is unclear. High levels of androgens have traditionally been viewed as driving abnormal proliferation leading to cancer, but it has also been suggested that low levels of androgen could induce selective pressure for abnormal cells. We formulate a mathematical model of androgen regulated prostate growth to study the effects of abnormal androgen levels on selection for pre-malignant phenotypes in early prostate cancer development. Results We find that cell turnover rate increases with decreasing androgen levels, which may increase the rate of mutation and malignant evolution. We model the evolution of a heterogeneous prostate cell population using a continuous state-transition model. Using this model we study selection for AR expression under different androgen levels and find that low androgen environments, caused either by low serum testosterone or by reduced 5?-reductase activity, select more strongly for elevated AR expression than do normal environments. High androgen actually slightly reduces selective pressure for AR upregulation. Moreover, our results suggest that an aberrant androgen environment may delay progression to a malignant phenotype, but result in a more dangerous cancer should one arise. Conclusions The model represents a useful initial framework for understanding the role of androgens in prostate cancer etiology, and it suggests that low androgen levels can increase selection for phenotypes resistant to hormonal therapy that may also be more aggressive. Moreover, clinical treatment with 5?-reductase inhibitors such as finasteride may increase the incidence of therapy resistant cancers. Reviewers This article was reviewed by Ariosto S. Silva (nominated by Marek Kimmel) and Marek Kimmel. PMID:20406442

2010-01-01

467

Analysis of strategic nuclear force levels using vector autoregressive techniques: a multi-nation econometric study  

SciTech Connect

The purpose of this dissertation is to examine the relationships between the strategic nuclear force levels of the US, Soviet Union, and other nuclear powers in order to provide a better understanding of the process by which arms levels are determined. By applying advanced econometric techniques to arms level data, the historical behavior of the nations may be dissected. The findings thus obtained may be compared to previous empirical findings and to the predictions of the theoretical literature on arms races. The major findings of this work are as follows. First, that there is interaction between the various components of the nuclear arsenals of the US and Soviet Union. Previous studies that examined only strategic aggregates missed these interactions. Second, the SALT I treaty did not significantly alter the behavior of these nations. Third, the nuclear-armed NATO nations (Great Britain and France) and possibly the People's Republic of China are important in determining the overall strategic posture of the US and USSR. Finally, process through which the arms levels of the nations studies are determined yield stationary time-series. That is, there is not an arms race with weapons levels spiraling upward indefinitely but a process that is stable in the short run.

Becker, A.D.

1986-01-01

468

The Use of Biosimulation in the Design of a Novel Multi-level Weight Loss Maintenance Program for Overweight Children  

PubMed Central

Objective Weight loss outcomes achieved through conventional behavior change interventions are prone to deterioration over time. Basic learning laboratory studies in the area of behavioral extinction and renewal and multi-level models of weight control offer clues as to why newly acquired weight loss skills are prone to relapse. According to these models, current clinic-based interventions may not be of sufficient duration or scope to allow for the practice of new skills across the multiple community contexts necessary to promote sustainable weight loss. Although longer, more intensive interventions with greater reach may hold the key to improving weight loss outcomes, it is difficult to test these assumptions in a time efficient and cost-effective manner. A research design tool that has been increasingly utilized in other fields (e.g., pharmaceuticals) is the use of biosimulation analyses. The present paper describes our research team's use of computer simulation models to assist in designing a study to test a novel, comprehensive socio-environmental treatment approach to weight loss maintenance in children ages 7 to 12 years. Methods Weight outcome data from the weight loss, weight maintenance, and follow-up phases of a recently completed randomized controlled trial (RCT) were used to describe the time course of a proposed, extended multi-level treatment program. Simulations were then conducted to project the expected changes in child percent overweight trajectories in the proposed study. Results A 12.9% decrease in percent overweight at 30 months was estimated based upon the midway point between models of best-case and worst-case weight maintenance scenarios. Conclusions Preliminary data and further analyses, including biosimulation projections, suggest that our socio-environmental approach to weight loss maintenance treatment is promising and warrants evaluation in a large-scale RCT. Biosimulation techniques may have utility in the design of future community-level interventions for the treatment and prevention of childhood overweight. PMID:20107468

Wilfley, Denise E.; Van Buren, Dorothy J.; Theim, Kelly R.; Stein, Richard I.; Saelens, Brian E.; Ezzet, Farkad; Russian, Angela C.; Perri, Michael G.; Epstein, Leonard H.

2011-01-01

469

Role of Human Sec63 in Modulating the Steady-State Levels of Multi-Spanning Membrane Proteins  

PubMed Central

The Sec61 translocon of the endoplasmic reticulum (ER) membrane forms an aqueous pore, allowing polypeptides to be transferred across or integrated into membranes. Protein translocation into the ER can occur co- and posttranslationally. In yeast, posttranslational translocation involves the heptameric translocase complex including its Sec62p and Sec63p subunits. The mammalian ER membrane contains orthologs of yeast Sec62p and Sec63p, but their function is poorly understood. Here, we analyzed the effects of excess and deficit Sec63 on various ER cargoes using human cell culture systems. The overexpression of Sec63 reduces the steady-state levels of viral and cellular multi-spanning membrane proteins in a cotranslational mode, while soluble and single-spanning ER reporters are not affected. Consistent with this, the knock-down of Sec63 increases the steady-state pools of polytopic ER proteins, suggesting a substrate-specific and regulatory function of Sec63 in ER import. Overexpressed Sec63 exerts its down-regulating activity on polytopic protein levels independent of its Sec62-interacting motif, indicating that it may not act in conjunction with Sec62 in human cells. The specific action of Sec63 is further sustained by our observations that the up-regulation of either Sec62 or two other ER proteins with lumenal J domains, like ERdj1 and ERdj4, does not compromise the steady-state level of a multi-spanning membrane reporter. A J domain-specific mutation of Sec63, proposed to weaken its interaction with the ER resident BiP chaperone, reduces the down-regulating capacity of excess Sec63, suggesting an involvement of BiP in this process. Together, these results suggest that Sec63 may perform a substrate-selective quantity control function during cotranslational ER import. PMID:23166619

Awe, Karin; Stieler, Jens; Doring, Tatjana; Fuser, Sabine; Prange, Reinhild

2012-01-01

470

ADORA2A Gene Variation, Caffeine, and Emotional Processing: A Multi-level Interaction on Startle Reflex  

PubMed Central

There is converging evidence for genetic, biochemical, and neuropsychological factors to increase the risk for anxiety and anxiety disorders. The pathogenesis of anxiety disorders is assumed to be influenced by a complex interaction of these individual risk factors on several levels, affecting intermediate phenotypes of anxiety such as the startle reflex. Thus, in the present double-blind, placebo-controlled study we attempted to paradigmatically investigate a multi-level pathogenetic model of anxiety by testing the effect of 300?mg caffeine citrate as an antagonist at the adenosine A2A receptor vs placebo on the emotion-potentiated (unpleasant, neutral, and pleasant International Affective Picture System pictures) startle reflex in 110 healthy individuals (male=56, female=54) stratified for the adenosine A2A receptor (ADORA2A) 1976T>C polymorphism (rs5751876). In addition to the expected main effect of picture category (highest startle amplitude for unpleasant, lowest for pleasant pictures) groups across all ADORA2A 1976T>C genotype and intervention (caffeine vs placebo) groups, an interaction effect of genotype, intervention, and picture category was discerned: In ADORA2A 1976TT risk genotype carriers, highest startle magnitudes were observed after caffeine administration in response to unpleasant pictures, with this effect arising particularly from the female subgroup. Our data point to a complex, multi-level, and potentially gender-specific pathogenetic model of anxiety, with genetic and biochemical factors interactively increasing the risk of maladaptive emotional processing and thereby possibly also anxiety disorders. The present findings may eventually aid in improving primary and secondary prevention by sharpening the risk profiles of anxiety-prone individuals. PMID:22012471

Domschke, Katharina; Gajewska, Agnieszka; Winter, Bernward; Herrmann, Martin J; Warrings, Bodo; Muhlberger, Andreas; Wosnitza, Katherina; Glotzbach, Evelyn; Conzelmann, Annette; Dlugos, Andrea; Fobker, Manfred; Jacob, Christian; Arolt, Volker; Reif, Andreas; Pauli, Paul; Zwanzger, Peter; Deckert, Jurgen

2012-01-01

471

ADORA2A Gene variation, caffeine, and emotional processing: a multi-level interaction on startle reflex.  

PubMed

There is converging evidence for genetic, biochemical, and neuropsychological factors to increase the risk for anxiety and anxiety disorders. The pathogenesis of anxiety disorders is assumed to be influenced by a complex interaction of these individual risk factors on several levels, affecting intermediate phenotypes of anxiety such as the startle reflex. Thus, in the present double-blind, placebo-controlled study we attempted to paradigmatically investigate a multi-level pathogenetic model of anxiety by testing the effect of 300?mg caffeine citrate as an antagonist at the adenosine A2A receptor vs placebo on the emotion-potentiated (unpleasant, neutral, and pleasant International Affective Picture System pictures) startle reflex in 110 healthy individuals (male=56, female=54) stratified for the adenosine A2A receptor (ADORA2A) 1976T>C polymorphism (rs5751876). In addition to the expected main effect of picture category (highest startle amplitude for unpleasant, lowest for pleasant pictures) groups across all ADORA2A 1976T>C genotype and intervention (caffeine vs placebo) groups, an interaction effect of genotype, intervention, and picture category was discerned: In ADORA2A 1976TT risk genotype carriers, highest startle magnitudes were observed after caffeine administration in response to unpleasant pictures, with this effect arising particularly from the female subgroup. Our data point to a complex, multi-level, and potentially gender-specific pathogenetic model of anxiety, with genetic and biochemical factors interactively increasing the risk of maladaptive emotional processing and thereby possibly also anxiety disorders. The present findings may eventually aid in improving primary and secondary prevention by sharpening the risk profiles of anxiety-prone individuals. PMID:22012471

Domschke, Katharina; Gajewska, Agnieszka; Winter, Bernward; Herrmann, Martin J; Warrings, Bodo; Mhlberger, Andreas; Wosnitza, Katherina; Glotzbach, Evelyn; Conzelmann, Annette; Dlugos, Andrea; Fobker, Manfred; Jacob, Christian; Arolt, Volker; Reif, Andreas; Pauli, Paul; Zwanzger, Peter; Deckert, Jrgen

2012-02-01

472

Region based route planning - Multi-abstraction route planning based on intermediate level vision processing  

NASA Technical Reports Server (NTRS)

Intermediate and high level processing operations are performed on vision data for the organization of images into more meaningful, higher-level topological representations by means of a region-based route planner (RBRP). The RBRP operates in terrain scenarios where some or most of the terrain is occluded, proceeding without a priori maps on the basis of two-dimensional representations and gradient-and-roughness information. Route planning is accomplished by three successive abstractions and yields a detailed point-by-point path by searching only within the boundaries of relatively small regions.

Doshi, Rajkumar S.; Lam, Raymond; White, James E.

1989-01-01

473

A parallel block multi-level preconditioner for the 3D incompressible Navier-Stokes equations  

NASA Astrophysics Data System (ADS)

The development of robust and efficient algorithms for both steady-state simulations and fully implicit time integration of the Navier-Stokes equations is an active research topic. To be effective, the linear subproblems generated by these methods require solution techniques that exhibit robust and rapid convergence. In particular, they should be insensitive to parameters in the problem such as mesh size, time step, and Reynolds number. In this context, we explore a parallel preconditioner based on a block factorization of the coefficient matrix generated in an Oseen nonlinear iteration for the primitive variable formulation of the system. The key to this preconditioner is the approximation of a certain Schur complement operator by a technique first proposed by Kay, Loghin, and Wathen [SIAM J. Sci. Comput., 2002] and Silvester, Elman, Kay, and Wathen [J. Comput. Appl. Math. 128 (2001) 261]. The resulting operator entails subsidiary computations (solutions of pressure Poisson and convection-diffusion subproblems) that are similar to those required for decoupled solution methods; however, in this case these solutions are applied as preconditioners to the coupled Oseen system. One important aspect of this approach is that the convection-diffusion and Poisson subproblems are significantly easier to solve than the entire coupled system, and a solver can be built using tools developed for the subproblems. In this paper, we apply smoothed aggregation algebraic multigrid to both subproblems. Previous work has focused on demonstrating the optimality of these preconditioners with respect to mesh size on serial, two-dimensional, steady-state computations employing geometric multi-grid methods; we focus on extending these methods to large-scale, parallel, three-dimensional, transient and steady-state simulations employing algebraic multigrid (AMG) methods. Our results display nearly optimal convergence rates for steady-state solutions as well as for transient solutions over a wide range of CFL numbers on the two-dimensional and three-dimensional lid-driven cavity problem.

Elman, Howard C.; Howle, Victoria E.; Shadid, John N.; Tuminaro, Ray S.

2003-05-01

474

Multi-grained Level of Detail Using a Hierarchical Seamless Texture Atlas Krzysztof Niski  

E-print Network

Laboratory Figure 1: Renderings of the 36 million sample Thai statue model and the 22 billion-sample USGS]: Computational Geometry and Object Modeling--Geometric algo- rithms, object hierarchies Keywords: level of detail, texture atlas, parametrization, geometry image, out-of-core 1 Introduction Since the early days

Cohen, Jonathan

475

Multi-objective analysis of ground-level ozone concentration control  

Microsoft Academic Search

To develop sound air quality plans, regional authorities should have instruments that link the complex behaviour of pollutants both in time and space with costs of emission reduction. The problem is particularly important for ground level ozone which forms kilometres away, hours later from the emission of its precursors. To approach this problem, a method (1) to identify local pollutant-precursor

Giorgio Guariso; Guido Pirovano; Marialuisa Volta

2004-01-01

476

An Evaluation of a Multi-Level Placement Program Concerning English Fundamentals and Writing Skills.  

ERIC Educational Resources Information Center

This study provides an evaluation of a program for teaching English Fundamentals and Writing Skills at Cerritos College (California). The new program divided the old English grammar and composition course into two ability-grouped sections: one dealing with sentences, and the other with paragraphs. Students started at their ability level and moved

Schaumburg, Gary F.

477

A Wavelet-Based Approach to Improve the E ciency of Multi-Level Surprise Mining?  

E-print Network

for NASA1. After three levels of o -line pre-processing, the temperature, ? This research has been funded in part by NSF grants EEC-9529152 IMSC ERC and ITR-0082826, NASA JPL contract nr. 961518, DARPA and USAF: genesis.jpl.nasa.gov html index.shtml. In this project, signals from GPS satellites are processed

Shahabi, Cyrus