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1

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

2

Fault recovery strategy for hybrid cascaded H-bridge multi-level inverters  

Microsoft Academic Search

In the configuration of the multilevel inverter which is used in this study, two cascaded H-bridge cells are connected in series with each phase of a three-phase three-level neutral- point clamped (NPC) inverter. The NPC inverter is fed by a single DC source; whereas, all of the cascaded H-bridge cells are supplied by capacitors. In this paper, in order to

Hossein Sepahvand; Mehdi Ferdowsi; Keith A. Corzine

2011-01-01

3

Multi-inverter UPS system with redundant load sharing control  

Microsoft Academic Search

The concept of a redundant multi-inverter UPS (uninterruptible power supply) system which includes extended monitoring of the status and the operating conditions of all power electronic equipment is described. Each block of the UPS system is monitored by two independent microcomputers that process the same data. The microcomputers are part of a redundant distributed monitoring system that is separately interlinked

J. Holtz; K.-H. Werner

1990-01-01

4

Multi-inverter UPS system with redundant load sharing control  

Microsoft Academic Search

The concept of a redundant multi-inverter UPS (uninterruptible power supply) system includes extended monitoring of the status and the operating conditions of all power electronic equipment. Each block of the UPS system is monitored by two independent microcomputers that process the same data. The microcomputers are part of a redundant distributed monitoring system, being separately interlinked by two serial data

Joachim Holtz; Karl-Heinz Werner

1989-01-01

5

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

6

A novel communication strategy for decentralized control of paralleled multi-inverter systems  

Microsoft Academic Search

A new communication strategy for decentralized control of paralleled multi-inverter systems is introduced in this paper. The proposed strategy utilizes the common mode signal's circuit in the paralleled system as a channel of communication between individual inverters. Source voltage synchronization for paralleled inverters is presented to demonstrate its effectiveness. One inverter module acts as a source and a synchronized signal

Yeong Jia Cheng; E. K. K. Sng

2006-01-01

7

Simulation of three level inverter with four leg  

Microsoft Academic Search

The paper presents an urgent problem of modem aircraft power supply development. Paper proposes three level inverter with four leg for frequency converter systems. Simulation results and analysis are presented.

A. V. Geist; S. A. Kharitonov

2008-01-01

8

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

E-print Network

the methodology for grid connection of renewable resources. Keywords ­ multilevel converter, cascaded H-bridges or in parallel to provide the desired voltage level to the inverter. The cascaded H-bridge multilevel inverter focuses on the single-phase 11-level (5 H- bridges) cascade multilevel inverter. II. MULTILEVEL INVERTER

Tolbert, Leon M.

9

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

10

Wind energy conversion based on seven-level cascaded H-bridge inverter using LabVIEW FPGA  

Microsoft Academic Search

In this paper, an isolated wind energy conversion system (WECS) based on the cascaded H-bridge multilevel inverter (CHBMLI) topology employing a permanent magnet synchronous generator (PMSG) driven by a variable speed wind turbine and feeding high power single-phase local loads has been proposed. A seven-level cascaded H-bridge inverter employing phase-shifted multi-carrier pulse width modulation is implemented using LabVIEW FPGA. The

Paulson Samuel; Nalamati Chandrashekhar; Rajesh Gupta

2010-01-01

11

Advanced Inverter Functions to Support High Levels of Distributed Solar: Policy and Regulatory Considerations (Brochure)  

SciTech Connect

This paper explains how advanced inverter functions (sometimes called 'smart inverters') contribute to the integration of high levels of solar PV generation onto the electrical grid and covers the contributions of advanced functions to maintaining grid stability. Policy and regulatory considerations associated with the deployment of advanced inverter functions are also introduced.

Not Available

2014-11-01

12

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

E-print Network

Development of New Three-Level Current-Source Inverter for Grid Connected Photovoltaic System and inverter, and its feasibility on grid connected photovoltaic system application. Using this new topology photovoltaic system 1. INTRODUCTION Solid state inverters allow to put photovoltaic (PV) systems into the power

Fujimoto, Hiroshi

13

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

E-print Network

-level inverter consists of a standard 3-leg inverter (one leg for each phase) and an H-bridge in series% higher than that obtained using a standard 3-leg inverter by itself. Index Terms-- Multilevel Converter in that all of them were capacitors, batteries, solar cells, etc. In [6], a multilevel converter was presented

Tolbert, Leon M.

14

A 7-level single DC source cascaded H-bridge multilevel inverters control using hybrid modulation  

Microsoft Academic Search

This paper presents a new hybrid cascaded H-bridge multilevel inverter (HCMLI) motor drive DTC control scheme for electric vehicles or hybrid electric vehicles where each phase of the inverter can be implemented using only a single DC source. Traditionally, each phase of the inverter require n DC source for 2n + 1 output voltage levels. In this paper, a scheme

F. Khoucha; A. Ales; A. Khoudiri; K. Marouani; M. E. H. Benbouzid; A. Kheloui

2010-01-01

15

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

16

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

Microsoft Academic Search

This contribution is focused on the investigation of a novel single-phase three-level PWM inverter in the kW power range, feeding a high power multi-mass ultrasonic motor (MM- USM) via a LLCC-type filter. In order to specify the power supply requirements, the operating principle of the MM-USM employed for a novel airborne brake actuator is briefed. The control scheme is studied,

Rongyuan Li; N. Froleke; Joachim Böcker

2007-01-01

17

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

18

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

19

A three level voltage space vector generation for open end winding IM using single voltage source driven dual two-level inverter  

Microsoft Academic Search

In this paper, a new scheme for three-level voltage space vector generation is proposed. In this work, the three-level inverter topology is realized by feeding an open winding induction motor with two two-level inverters, fed from a single dc source having the magnitude half compared to the NPC three-level inverter. Compared to existing three-level inverter topologies for open-end winding induction

K. Sivakumar; Anandarup Das; Rijil Ramchand; Chintan Patel; K. Gopakumar

2009-01-01

20

A Hybrid Multilevel Inverter Topology for an Open-End Winding Induction-Motor Drive Using Two-Level Inverters in Series With a Capacitor-Fed H-Bridge Cell  

Microsoft Academic Search

In this paper, a new five-level inverter topology for open-end winding induction-motor (IM) drive is proposed. The open-end winding IM is fed from one end with a two-level inverter in series with a capacitor-fed H-bridge cell, while the other end is connected to a conventional two-level inverter. The combined inverter system produces voltage space-vector locations identical to that of a

K. Sivakumar; A. Das; R. Ramchand; C. Patel; K. Gopakumar

2010-01-01

21

Sensorless 3-level inverter-fed induction motor drive based on indirect torque control  

Microsoft Academic Search

A sensorless induction motor drive fed by 3-level inverter is presented, which combines the principle of indirect torque control, space vector modulation (SVM), speed adaptive flux observer and fuzzy logic controller (FLC). By using SVM, the switching frequency is kept constant and it is easy to solve the problems such as neutral point balance, voltage jump, etc, and more accurate

Yongchang Zhang; Zhengming Zhao; Ting Lu; Liqiang Yuan

2009-01-01

22

PWM inverter technology  

NASA Astrophysics Data System (ADS)

The use of pulse-width-modulated (PWM) inverter technology by on-line uninterruptible power supplies (UPSs) of 250 VA-750 kVA rating improves transient performance, lowers harmonic distortion, and enhances nonlinear load performance. An account is presently given of the means employed for optimization of a PWM inverter used in a multi-kHz UPS. By using computer modeling to optimize the feedback control loop, the best level of response was furnished, while minimizing switching losses and achieving the highest level of efficiency.

Perra, Andre

1992-04-01

23

Low-Frequency Sea Level Variability and the Inverted Barometer Effect  

Microsoft Academic Search

For a dynamical interpretation of sea level records, estimates are needed of the isostatic, or so-called inverted barometer, signals (ib) associated with the ocean response to atmospheric loading. Seasonal and longer-period ib signals are evaluated over the global ocean for the period 1958-2000 using monthly sea level pressure fields from two different atmospheric reanalyses. Variability and linear trends in ib

Rui M. Ponte

2006-01-01

24

Obstacle detection and mapping in low-cost, low-power multi-robot systems using an Inverted  

E-print Network

Obstacle detection and mapping in low-cost, low-power multi-robot systems using an Inverted experiments show promising results. Keywords: computational power, low-cost, low-energy, power consump- tion solutions with numerous sensors and computers. To the authors knowledge, a solution for low-cost, low

Paris-Sud XI, Université de

25

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

26

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 González; Josep Balcells

2006-01-01

27

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

NASA Astrophysics Data System (ADS)

Graphene has attracted considerable interest for future electronics, but the absence of a bandgap limits its direct applicability in transistors and logic devices. Recently, other layered materials such as molybdenum disulphide (MoS2) have been investigated to address this challenge. Here, we report the vertical integration of multi-heterostructures of layered materials for the fabrication of a new generation of vertical field-effect transistors (VFETs) with a room temperature on-off ratio > 103 and a high current density of up to 5,000?A?cm-2. An n-channel VFET is created by sandwiching few-layer MoS2 as the semiconducting channel between a monolayer graphene sheet and a metal thin film. This approach offers a general strategy for the vertical integration of p- and n-channel transistors for high-performance logic applications. As an example, we demonstrate a complementary inverter with a larger-than-unity voltage gain by vertically stacking graphene, Bi2Sr2Co2O8 (p-channel), graphene, MoS2 (n-channel) and a metal thin film in sequence. The ability to simultaneously achieve a high on-off ratio, a high current density and a logic function in such vertically stacked multi-heterostructures can open up possibilities for three-dimensional integration in future electronics.

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

2013-03-01

28

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

PubMed

Graphene has attracted considerable interest for future electronics, but the absence of a bandgap limits its direct applicability in transistors and logic devices. Recently, other layered materials such as molybdenum disulphide (MoS(2)) have been investigated to address this challenge. Here, we report the vertical integration of multi-heterostructures of layered materials for the fabrication of a new generation of vertical field-effect transistors (VFETs) with a room temperature on-off ratio > 10(3) and a high current density of up to 5,000 A cm(-2). An n-channel VFET is created by sandwiching few-layer MoS(2) as the semiconducting channel between a monolayer graphene sheet and a metal thin film. This approach offers a general strategy for the vertical integration of p- and n-channel transistors for high-performance logic applications. As an example, we demonstrate a complementary inverter with a larger-than-unity voltage gain by vertically stacking graphene, Bi(2)Sr(2)Co(2)O(8) (p-channel), graphene, MoS(2) (n-channel) and a metal thin film in sequence. The ability to simultaneously achieve a high on-off ratio, a high current density and a logic function in such vertically stacked multi-heterostructures can open up possibilities for three-dimensional integration in future electronics. PMID:23241535

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

2013-03-01

29

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

SciTech Connect

A method is presented showing that a 5-level cascade multilevel inverter for a three-phase permanent magnet sychronous motor drive can be implemented using only a single DC link to supply a standard 3-leg inverter along with three full H-bridges supplied by capacitors. It is shown that the capacitor voltages can be regulated while achieving an output voltage waveform that is 20% greater than that obained using the standard 3-leg inverter alone. Finally conditions are given in terms of the power factor and modulation index that determine when the capacitor voltage can regulated.

Chiasson, J. N. [University of Tennessee, Knoxville (UTK)

2006-10-01

30

Multi-Resolution Time-Domain and Level-Set Techniques for Multi-Domain/Multi-physics/Multi-Phase Simulations  

E-print Network

, multi-physics simulations, biosensors, nanostructures, solid-state, multi-phase structures. Ceramics between Maxwell, solid-state and solid/liquid-interface equations. Numerous examplesMulti-Resolution Time-Domain and Level-Set Techniques for Multi- Domain/Multi-physics

Tentzeris, Manos

31

Advanced Inverter Technology for High Penetration Levels of PV Generation in Distribution Systems  

SciTech Connect

This subcontract report was completed under the auspices of the NREL/SCE High-Penetration Photovoltaic (PV) Integration Project, which is co-funded by the U.S. Department of Energy (DOE) Office of Energy Efficiency and Renewable Energy (EERE) and the California Solar Initiative (CSI) Research, Development, Demonstration, and Deployment (RD&D) program funded by the California Public Utility Commission (CPUC) and managed by Itron. This project is focused on modeling, quantifying, and mitigating the impacts of large utility-scale PV systems (generally 1-5 MW in size) that are interconnected to the distribution system. This report discusses the concerns utilities have when interconnecting large PV systems that interconnect using PV inverters (a specific application of frequency converters). Additionally, a number of capabilities of PV inverters are described that could be implemented to mitigate the distribution system-level impacts of high-penetration PV integration. Finally, the main issues that need to be addressed to ease the interconnection of large PV systems to the distribution system are presented.

Schauder, C.

2014-03-01

32

Three-phase multi-level DC-AC converter using three-phase, coupled inductors  

Microsoft Academic Search

A new three-phase multi-level DC-AC converter with three-phase coupled inductors is presented in this work. The related converter is employed only as an inverter here. Initially the power stage diagram and the modulator are shown and discussed. Their main characteristics are described and the more relevant waveforms, generated by simulation, are shown. Next, the operation of the converter with sinusoidal

Ivo Barbi; Romeu Hausmann

2009-01-01

33

Multi-purpose grid-tied inverter with smart grid capabilities  

NASA Astrophysics Data System (ADS)

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

Liyanagedera, Chamika Mihiranga

34

Optical cooling in multi-level systems  

NASA Astrophysics Data System (ADS)

A theoretical model for optical cooling is developed, which yields the overall efficiency of a single endpumped cooling system. This model includes the effects of background absorption and pump saturation, while in multi-level systems, the model accounts for the important energy transfer processes. Two-level efficiency is evaluated for the case of Yb:YAG and compared with a hypothetical three-level material with identical spectral properties. This model is readily modified to include more levels and different materials.

Bowman, Steven R.; Ganem, Joseph; Brown, Christopher G.

2014-02-01

35

MultiLevel Web Surfing  

Microsoft Academic Search

Web browsers have become the most popular interactive interfaces ever developed and widely deployed in the computing history. Through links embedded in a web page, a user can browse virtually any digital resources in the world. Although these links are naturally interconnected and hierarchical, the browsing model is typically in linear and at any point of time only one-level of

Tsang-ming Jiang; Wenyu Cao; Dale Clark

2001-01-01

36

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

37

Multilevel cascade voltage source inverter with seperate 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.

Peng, Fang Zheng (Oak Ridge, TN); Lai, Jih-Sheng (Knoxville, TN)

1997-01-01

38

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

39

Multilevel cascade voltage source inverter with seperate 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.

Peng, Fang Zheng (Knoxville, TN); Lai, Jih-Sheng (Blacksburg, VA)

2002-01-01

40

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; Štumberger, Gorazd

41

A Transformerless Motor Drive with a Five-Level Diode-Clamped PWM Inverter for Fan/Blower Loads  

NASA Astrophysics Data System (ADS)

This paper describes a 6.6-kV adjustable-speed motor drive for use in fans, blowers, and pumps without a transformer. The power-conversion system consists of a diode rectifier, a five-level diode-clamped PWM inverter, and a voltage-balancing circuit. A 200-V 5.5-kW downscale model is developed, constructed, and tested. The five-level PWM inverter and the voltage-balancing circuit are studied in detail. Experimental results obtained from testing the 200-V downscale model confirm the viability and effectiveness of the 6.6-kV adjustable-speed motor drive, indicating that the dc mean voltages of the four split dc capacitors are well balanced under all the given operating conditions.

Hasegawa, Kazunori; Hatti, Natchpong; Akagi, Hirofumi

42

New direct torque neuro-fuzzy control based SVM-three level inverter-fed induction motor  

Microsoft Academic Search

In this paper, a novel direct torque neuro-fuzzy control (DTCNF) scheme combining with space voltage modulation (SVM) technique\\u000a of a three levels inverter is presented. Using neuro-fuzzy technique, the reference space voltage vector can be obtained dynamically\\u000a in terms of torque error, stator flux error and the angle of stator flux. Compared with conventional direct torque control\\u000a (C_DTC), in this

Toufouti Riad; Benalla Hocine; Meziane Salima

2010-01-01

43

Multi-level coupled cluster theory  

NASA Astrophysics Data System (ADS)

We present a general formalism where different levels of coupled cluster theory can be applied to different parts of the molecular system. The system is partitioned into subsystems by Cholesky decomposition of the one-electron Hartree-Fock density matrix. In this way the system can be divided across chemical bonds without discontinuities arising. The coupled cluster wave function is defined in terms of cluster operators for each part and these are determined from a set of coupled equations. The total wave function fulfills the Pauli-principle across all borders and levels of electron correlation. We develop the associated response theory for this multi-level coupled cluster theory and present proof of principle applications. The formalism is an essential tool in order to obtain size-intensive complexity in the calculation of local molecular properties.

Myhre, Rolf H.; Sánchez de Merás, Alfredo M. J.; Koch, Henrik

2014-12-01

44

Mechanisms for Multi-Level Marketing Moshe Tennenholtz  

E-print Network

-called affiliate marketing, direct marketing, and multi-level marketing all refer to (overlapping) approachesMechanisms for Multi-Level Marketing Yuval Emek Ron Karidi Moshe Tennenholtz Aviv Zohar§ Abstract Multi-level marketing is a marketing approach that motivates its participants to promote a certain

45

Mechanisms for Multi-Level Marketing Computer Engineering and  

E-print Network

-called affiliate marketing, direct mar- keting, and multi-level marketing all refer to (overlapping) approachesMechanisms for Multi-Level Marketing Yuval Emek Computer Engineering and Networks Laboratory ETH View, CA, USA avivz@microsoft.com ABSTRACT Multi-level marketing is a marketing approach that moti

Sandholm, Tuomas W.

46

Multi level programming Paradigm for Extreme Computing  

NASA Astrophysics Data System (ADS)

Abstract: In order to propose a framework and programming paradigms for post-petascale computing, on the road to exascale computing and beyond, we introduced new languages, associated with a hierarchical multi-level programming paradigm, allowing scientific end-users and developers to program highly hierarchical architectures designed for extreme computing. In this paper, we explain the interest of such hierarchical multi-level programming paradigm for extreme computing and its well adaptation to several large computational science applications, such as for linear algebra solvers used for reactor core physic. We describe the YML language and framework allowing describing graphs of parallel components, which may be developed using PGAS-like language such as XMP, scheduled and computed on supercomputers. Then, we propose experimentations on supercomputers (such as the "K" and "Hooper" ones) of the hybrid method MERAM (Multiple Explicitly Restarted Arnoldi Method) as a case study for iterative methods manipulating sparse matrices, and the block Gauss-Jordan method as a case study for direct method manipulating dense matrices. We conclude proposing evolutions for this programming paradigm.

Petiton, S.; Sato, M.; Emad, N.; Calvin, C.; Tsuji, M.; Dandouna, M.

2014-06-01

47

Generation of multi-cycle THz-pulses via optical rectification in periodically inverted GaAs  

NASA Astrophysics Data System (ADS)

We demonstrate an efficient room temperature source of narrow-bandwidth terahertz (THz) radiation using femtosecond pump pulses and periodic GaAs structure as a nonlinear material. In the past, several THz generation schemes exploited optical rectification in nonlinear crystals using femtosecond laser technology. Most of them generated single-cycle THz-pulses with broad bandwidth, using nonlinear crystals shorter than the phase-matching coherence length. Recently a novel technique to generate multi-cycle THz-pulses in the pre-engineered domain structure of periodically-poled lithium niobate (PPLN) crystals has been demonstrated. Quasi-phase matching (QPM) structures such as PPLN consist of a periodic system of domains of inverted crystal orientation. The sign of second order nonlinear polarization generated by femtosecond pulses is inverted at domain boundaries. If domain length is comparable with coherence length, QPM between THz-wave and nonlinear polarization extends the interaction length between THz and optical pulses. In the present work, using periodic GaAs structures we have achieved exceptionally high photon as well as energy conversion efficiency: 3% and 0.07% respectively. We have examined two different types of periodic QPM GaAs samples: diffusion-bonded GaAs wafers and all-epitaxially-grown orientation-patterned GaAs crystals with 3-10 mm thicknesses. The incident optical pulse energy was in the micro-Joule range and pulse duration was ~100 fsec. We measured spectral properties of THz radiation using Michelson interferometer and a bolometer. Narrow-bandwidth (~100GHz) THz output, tunable between 1 and 3 THz, was achieved. THz frequency was tuned either by tuning the light source wavelength between 2 and 4.4 microns, or by selecting GaAs samples with different QPM periods. Our theoretical analysis, based on known GaAs dispersion properties, shows good agreement between the measured and predicted THz frequencies.

Lee, Yun-Shik; Vodopyanov, K. L.; Hurlbut, W. C.; Danielson, J. R.; Kozlov, V. G.; Bliss, D. F.; Fejer, M. M.

2006-02-01

48

A Five-Level Inverter Scheme for a Four-Pole Induction Motor Drive by Feeding the Identical Voltage-Profile Windings From Both Sides  

Microsoft Academic Search

This paper presents a five-level inverter scheme with four two-level inverters for a four-pole induction motor (IM) drive. In a conventional three-phase four-pole IM, there exists two identical voltage-profile winding coil groups per phase around the armature, which are connected in series and spatially apart by two pole pitches. In this paper, these two identical voltage-profile pole-pair winding coils in

K. Sivakumar; Anandarup Das; Rijil Ramchand; Chintan Patel; K. Gopakumar

2010-01-01

49

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

50

Milliwatt dc/dc Inverter  

NASA Technical Reports Server (NTRS)

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

Mclyman, C. W.

1983-01-01

51

A DC-Voltage-Balancing Circuit for a Five-Level Diode-Clamped PWM Inverter Intended for Motor Drives  

NASA Astrophysics Data System (ADS)

This paper proposes a new dc-voltage-balancing circuit for a five-level diode-clamped inverter intended for a medium-voltage motor drive. This circuit consists of two unidirectional choppers and a single coupled inductor with two galvanically-isolated windings. The dc magnetic fluxes in the magnetic core, which are generated by the two windings, cancel out each other. Therefore, the inductor does not generate any dc-magnetic flux in the magnetic core. This makes the inductor compact by a factor of six compared to previously used balancing circuits containing two non-coupled inductors. Experimental results obtained from a 200-V 5.5-kW downscaled model verify that the dc mean voltages of the four split dc capacitors are balanced well under all operating conditions.

Hasegawa, Kazunori; Akagi, Hirofumi

52

Cascaded Nine-Level Inverter for Hybrid-Series Active Power Filter, Using Industrial Controller  

Microsoft Academic Search

An industrial controller, specifically designed for two- and three-level converters, was adapted to work on an asymmetrical nine-level active power filter (APF). The controller is now able to make all required tasks for the correct operation of the APF, such as current-harmonic elimination and removal of high-frequency noise. The low switching-frequency operation of the nine-level converter was an important advantage

Alexander Varschavsky; Juan Dixon; Mauricio Rotella; Luis Moran

2010-01-01

53

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

E-print Network

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

Tolbert, Leon M.

54

IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS, VOL. 57, NO. 8, AUGUST 2010 2761 Cascaded Nine-Level Inverter for Hybrid-Series  

E-print Network

IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS, VOL. 57, NO. 8, AUGUST 2010 2761 Cascaded Nine. I. INTRODUCTION THE constant increase in power electronic devices, used by industrial and commercial-Level Inverter for Hybrid-Series Active Power Filter, Using Industrial Controller Alexander Varschavsky, Juan

Catholic University of Chile (Universidad Católica de Chile)

55

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

56

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

1998-01-01

57

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

E-print Network

and Luis Morán Abstract The application of high-level multilevel converters in traction systems is very, the bridges of each converter work at a very low switching frequency, which gives the possibility to work of conventional "H-Bridges". This technology allows modulating the output voltage by amplitude (AM) and pulse

Catholic University of Chile (Universidad Católica de Chile)

58

Robust Multi-modal and Multi-unit Feature Level Fusion of Face and Iris Biometrics  

Microsoft Academic Search

Multi-biometrics has recently emerged as a mean of more robust and efficient personal verification and identification. Exploiting\\u000a information from multiple sources at various levels i.e., feature, score, rank or decision, the false acceptance and rejection\\u000a rates can be considerably reduced. Among all, feature level fusion is relatively an understudied problem. This paper addresses\\u000a the feature level fusion of multi-modal and

Ajita Rattani; Massimo Tistarelli

2009-01-01

59

Invert Recommendations The Invert project  

E-print Network

, Institute of Power Systems and Energy Economics, Vienna University of Technology, Austria. Project partners Kingdom - AGH ­ University of Science and Technology, Poland - CEETA ­ Centro de Estudos em Economia da#12;Invert ­ Recommendations The Invert project: Research project within the Altener Program

60

Multi Core Design for Chip Level Multiprocessing  

Microsoft Academic Search

\\u000a Chip level integration continues to be a driving force in the computer industry. It lowers the cost and increases performance\\u000a of computer systems, creating a remarkable rate of improvement in all processors, from handheld devices to supercomputers.\\u000a Processor chips now (in 2009) contain up to two billion transistors. Gordon Moore outlined a roadmap for chip level integration\\u000a in 1965, which

Tryggve Fossum

2008-01-01

61

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

62

Multi Core Design for Chip Level Multiprocessing  

NASA Astrophysics Data System (ADS)

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

Fossum, Tryggve

63

Multi-level Hierarchical Poly Tree computer architectures  

NASA Technical Reports Server (NTRS)

Based on the concept of hierarchical substructuring, this paper develops an optimal multi-level Hierarchical Poly Tree (HPT) parallel computer architecture scheme which is applicable to the solution of finite element and difference simulations. Emphasis is given to minimizing computational effort, in-core/out-of-core memory requirements, and the data transfer between processors. In addition, a simplified communications network that reduces the number of I/O channels between processors is presented. HPT configurations that yield optimal superlinearities are also demonstrated. Moreover, to generalize the scope of applicability, special attention is given to developing: (1) multi-level reduction trees which provide an orderly/optimal procedure by which model densification/simplification can be achieved, as well as (2) methodologies enabling processor grading that yields architectures with varying types of multi-level granularity.

Padovan, Joe; Gute, Doug

1990-01-01

64

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

Microsoft Academic Search

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

Nikola Celanovic; Dushan Boroyevich

2000-01-01

65

tMANS -the Multi-Scale Agent-Based Networked Simulation for the Study of Multi-Scale, Multi-Level Biological and Social Phenomena  

E-print Network

tMANS - the Multi-Scale Agent-Based Networked Simulation for the Study of Multi-Scale, Multi-Level Biological and Social Phenomena Matthias Scheutz (*), Greg Madey (*), and Sunny Boyd (**) (*) Department a multi-scale agent-based framework towards understanding and modeling multi-scale interdependent

Boyd, Sunny K.

66

A Multi-level Algorithm for Quantum-impurity Models  

E-print Network

A continuous-time path integral Quantum Monte Carlo method using the directed-loop algorithm is developed to simulate the Anderson single-impurity model in the occupation number basis. Although the method suffers from a sign problem at low temperatures, the new algorithm has many advantages over conventional algorithms. For example, the model can be easily simulated in the Kondo limit without time discretization errors. Further, many observables including the impurity susceptibility and a variety of fermionic observables can be calculated efficiently. Finally the new approach allows us to explore a general technique, called the multi-level algorithm, to solve the sign problem. We find that the multi-level algorithm is able to generate an exponentially large number of configurations with an effort that grows as a polynomial in inverse temperature such that configurations with a positive sign dominate over those with negative signs. Our algorithm can be easily generalized to other multi-impurity problems.

Jaebeom Yoo; Shailesh Chandrasekharan; Harold U. Baranger

2004-08-06

67

Ecological Site Descriptions and Forest Service Multi-level  

E-print Network

Ecological Site Descriptions and Forest Service Multi-level Ecosystem Assessments, Planning, land & resource planning · Regional ­ Conservation/restoration strategies · Forest ­ Land and resource management plans · Landscape/Watershed ­ Assess resource conditions and landscape processes · Project

68

IEEE 802.3 Tutorial Multi-Level Analog Signaling  

E-print Network

IEEE 802.3 Tutorial Multi-Level Analog Signaling Techniques for 10 Gigabit Ethernet #12;IEEE 802 found (e.g. DMD, MMF launch) · MAS is dominant in modems, DSL, Cu Ethernet... u Invaluable to re No hard requirement to use high-speed compensation #12;IEEE 802 Tutorial7 Features · MAS enables a single

Miller, Ethan L.

69

Multi-level converters for three-phase photovoltaic applications  

E-print Network

Multi-level converters for three-phase photovoltaic applications Renato M. Nakagomi, Ye Zhao, Brad a switching matrix device and photovoltaic (PV) panels. The approach is based on the dynamic reconfiguration photovoltaic PV panels. The number of PV panels that are connected to the load can be altered using dynamic

Lehman, Brad

70

Multilevel dodecagonal space vector generation for Open-end winding induction motor drive using conventional three level inverters  

Microsoft Academic Search

A novel dodecagonal space vector structure for induction motor drive is presented in this paper. It consists of two dodecagons, with the radius of the outer one twice the inner one. Compared to existing dodecagonal space vector structures, to achieve the same PWM output voltage quality, the proposed topology lowers the switching frequency of the inverters and reduces the device

Anandarup Das; K. Sivakumar; Rijil Ramchand; Chintan Patel; K. Gopakumar

2009-01-01

71

Flexible Job Shop Scheduling with Multi-level Job Structures  

NASA Astrophysics Data System (ADS)

This paper deals with a scheduling problem in a flexible job shop with multi-level job structures where end products are assembled from sub-assemblies or manufactured components. For such shops MRP (Material Requirement Planning) logic is frequently used to synchronize and pace the production activities for the required parts. However, in MRP, the planning of operational-level activities is left to short term scheduling. So, we need a good scheduling algorithm to generate feasible schedules taking into account shop floor characteristics and multi-level job structures used in MRP. In this paper, we present a GA (Genetic Algorithm) solution for this complex scheduling problem based on a new gene to reflect the machine assignment, operation sequences and the levels of the operations relative to final assembly operation. The relative operation level is the control parameter that paces the completion timing of the components belonging to the same branch in the multi-level job hierarchy. We compare the genetic algorithm with several dispatching rules in terms of total tardiness and the genetic algorithm shows outstanding performance for about forty modified standard job-shop problem instances.

Jang, Yang-Ja; Kim, Ki-Dong; Jang, Seong-Yong; Park, Jinwoo

72

Simplified High-Power Inverter  

NASA Technical Reports Server (NTRS)

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

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

1984-01-01

73

Towards a multi-level game model for influenza epidemics.  

PubMed

Although game theory has been first invented to reason with economic scenarios with rational agents, it has since been extended into many other fields including biological and medical sciences. In this paper we propose to model the interactions between virus and human in an influenza epidemic in a two player, adversarial game scenario with multiple levels of abstraction. As conventional game representations are inadequate in this complex problem domain, we propose Object Oriented Multi-Agent Influence Diagrams (OO-MAID), a novel graphical representation for multi-level games, which takes advantage of both organizational information and probabilistic independence in the problem domain. The OO-MAID representation can be readily applied in similar medical independent characteristics. We demonstrate the feasibility of this novel approach with sample models in the domain. PMID:20841728

Chen, Qiongyu; Leong, Tze-Yun

2010-01-01

74

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

75

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

76

Overload protection system for power inverter  

NASA Technical Reports Server (NTRS)

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

Nagano, S. (inventor)

1977-01-01

77

Efficient Multidisciplinary Analysis Procedure Using Multi-Level Parallelization Approach  

NASA Technical Reports Server (NTRS)

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

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

1997-01-01

78

Fuzzy comprehensive evaluation of water level in Weihe River based on multi-objective and multi-level decision making method  

Microsoft Academic Search

In this paper, domestic water, industrial water, agricultural water and comprehensive water use level in Weihe River Valley in Shaanxi Province are studied to strengthen water resource management and realize sustainable use of water in Weihe River, fuzzy comprehensive evaluation model established and the comprehensive wateruse level evaluated based on multi-objective and multi-level decision making methods. It shows that the

Shunsheng Wangl; Liangjun Fei; Yuping Han; Jianlong Zhangl

2010-01-01

79

Femtosecond phase spectroscopy of multi-level systems: Phthalocyanines  

NASA Astrophysics Data System (ADS)

A femtosecond frequency-domain interferometer is applied to metal-free and vanadyl phthalocyanine (H2Pc and VOPc) thin films to measure time-resolved difference phase and transmission spectra simultaneously. For both samples, the phase-change dynamics is different from the transmission-change dynamics at 620 nm, reflecting that the phthalocyanines (Pc) cannot be modeled with a two-level system but by a multi-level or inhomogeneously broadened system, in which each level pair exhibits different relaxation dynamics. Because of this dynamical difference, a phase-change measurement is required to correct distortion of the transient spectra due to induced phase modulation of probe pulses. Near zero time delay, the phase and transmission changes show different growth behavior. This behavior is explained by antisymmetric amplitude and phase gratings which are produced by coherent coupling between frequency-chirped pump and probe pulses.

Tokunaga, E.; Terasaki, A.; Wada, T.; Sasabe, H.; Kobayashi, T.

1996-09-01

80

A Combination of Hexagonal and 12-Sided Polygonal Voltage Space Vector PWM Control for IM Drives Using Cascaded Two-Level Inverters  

Microsoft Academic Search

This paper proposes a multilevel inverter configuration which produces a hexagonal voltage space vector structure in the lower modulation region and a 12-sided polygonal space vector structure in the overmodulation region. A conventional multilevel inverter produces 6n plusmn 1 (n = odd) harmonics in the phase voltage during overmodulation and in the extreme square-wave mode of operation. However, this inverter

Anandarup Das; K. Sivakumar; Rijil Ramchand; Chintan Patel; K. Gopakumar

2009-01-01

81

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

82

Politics of innovation in multi-level water governance systems  

NASA Astrophysics Data System (ADS)

Innovations are being proposed in many countries in order to support change towards more sustainable and water secure futures. However, the extent to which they can be implemented is subject to complex politics and powerful coalitions across multi-level governance systems and scales of interest. Exactly how innovation uptake can be best facilitated or blocked in these complex systems is thus a matter of important practical and research interest in water cycle management. From intervention research studies in Australia, China and Bulgaria, this paper seeks to describe and analyse the behind-the-scenes struggles and coalition-building that occurs between water utility providers, private companies, experts, communities and all levels of government in an effort to support or block specific innovations. The research findings suggest that in order to ensure successful passage of the proposed innovations, champions for it are required from at least two administrative levels, including one with innovation implementation capacity, as part of a larger supportive coalition. Higher governance levels can play an important enabling role in facilitating the passage of certain types of innovations that may be in competition with currently entrenched systems of water management. Due to a range of natural biases, experts on certain innovations and disciplines may form part of supporting or blocking coalitions but their evaluations of worth for water system sustainability and security are likely to be subject to competing claims based on different values and expertise, so may not necessarily be of use in resolving questions of "best courses of action". This remains a political values-based decision to be negotiated through the receiving multi-level water governance system.

Daniell, Katherine A.; Coombes, Peter J.; White, Ian

2014-11-01

83

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

84

COORDINATION OF PLANNING AND SCHEDULING TECHNIQUES FOR A DISTRIBUTED, MULTI-LEVEL,  

E-print Network

for agents operating in heterogeneous, multi-agent environments is governed by the nature of the environmentCOORDINATION OF PLANNING AND SCHEDULING TECHNIQUES FOR A DISTRIBUTED, MULTI-LEVEL, MULTI-AGENT systems. 1 INTRODUCTION In large-scale, distributed, multi-agent systems (MAS) that span multiple domains

Schmidt, Douglas C.

85

Power inverters  

DOEpatents

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

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

2011-11-15

86

Multi-Level Opinion Dynamics under Bounded Confidence  

PubMed Central

Opinion dynamics focuses on the opinion evolution in a social community. Recently, some models of continuous opinion dynamics under bounded confidence were proposed by Deffuant and Krause, et al. In the literature, agents were generally assumed to have a homogeneous confidence level. This paper proposes an extended model for a group of agents with heterogeneous confidence levels. First, a social differentiation theory is introduced and a social group is divided into opinion subgroups with distinct confidence levels. Second, a multi-level heterogeneous opinion formation model is formulated under the framework of bounded confidence. Finally, computer simulations are conducted to study the collective opinion evolution, focusing on three key factors: the fractions of heterogeneous agents, the initial opinions, and the group size. The simulation results demonstrate that the number of final opinions depends on the fraction of close-minded agents when the group size and the initial opinions are fixed; the final opinions converge more easily when the initial opinions are closer; and the number of final opinions can be approximately modeled by a linear increasing function of the group size and the increasing rate is the fraction of close-minded agents. PMID:23028458

Kou, Gang; Zhao, Yiyi; Peng, Yi; Shi, Yong

2012-01-01

87

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

88

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

SciTech Connect

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

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

2014-11-01

89

The genetical theory of multi-level selection.  

PubMed

The theory of multi-level selection (MLS) is beset with conceptual difficulties. Whilst it is widely agreed that covariance between group trait and group fitness may arise in the natural world and drive a response to "group selection", ambiguity exists over the precise meaning of group trait and group fitness and as to whether group selection should be defined according to changes in frequencies of different types of individual or different types of group. Moreover, the theory of MLS has failed to properly engage with the problem of class structure, which greatly limits its empirical application to, for example, social insects whose colonies are structured into separate age, sex, caste and ploidy classes. Here, I develop a genetical theory of MLS, to address these problems. I show that taking a genetical approach facilitates a decomposition of group-level traits - including fitness - into the separate contributions made by each constituent individual, even in the context of so-called "emergence". However, I uncover a novel problem with the group-oriented approach: in many scenarios, it may not be possible to express a covariance between trait and fitness at the level of the social group, because the group's constituents belong to separate, irreconcilable classes. This article is protected by copyright. All rights reserved. PMID:25475922

Gardner, Andy

2014-12-01

90

A Multi-Level Parallelization Concept for High-Fidelity Multi-Block Solvers  

NASA Technical Reports Server (NTRS)

The integration of high-fidelity Computational Fluid Dynamics (CFD) analysis tools with the industrial design process benefits greatly from the robust implementations that are transportable across a wide range of computer architectures. In the present work, a hybrid domain-decomposition and parallelization concept was developed and implemented into the widely-used NASA multi-block Computational Fluid Dynamics (CFD) packages implemented in ENSAERO and OVERFLOW. The new parallel solver concept, PENS (Parallel Euler Navier-Stokes Solver), employs both fine and coarse granularity in data partitioning as well as data coalescing to obtain the desired load-balance characteristics on the available computer platforms. This multi-level parallelism implementation itself introduces no changes to the numerical results, hence the original fidelity of the packages are identically preserved. The present implementation uses the Message Passing Interface (MPI) library for interprocessor message passing and memory accessing. By choosing an appropriate combination of the available partitioning and coalescing capabilities only during the execution stage, the PENS solver becomes adaptable to different computer architectures from shared-memory to distributed-memory platforms with varying degrees of parallelism. The PENS implementation on the IBM SP2 distributed memory environment at the NASA Ames Research Center obtains 85 percent scalable parallel performance using fine-grain partitioning of single-block CFD domains using up to 128 wide computational nodes. Multi-block CFD simulations of complete aircraft simulations achieve 75 percent perfect load-balanced executions using data coalescing and the two levels of parallelism. SGI PowerChallenge, SGI Origin 2000, and a cluster of workstations are the other platforms where the robustness of the implementation is tested. The performance behavior on the other computer platforms with a variety of realistic problems will be included as this on-going study progresses.

Hatay, Ferhat F.; Jespersen, Dennis C.; Guruswamy, Guru P.; Rizk, Yehia M.; Byun, Chansup; Gee, Ken; VanDalsem, William R. (Technical Monitor)

1997-01-01

91

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

E-print Network

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

Chang, Shih-Fu

92

A predictive sampling scale model for direct torque control of the induction machine fed by multilevel voltage-source inverters  

NASA Astrophysics Data System (ADS)

This paper is aimed at the characterization of Electric Power Drive Systems based on the Induction Machine fed by Multi-level Voltage-source inverters, to be used within instantaneous torque and flux control methodologies. The input/output transfer function for a N-level inverter is discussed and the correspondent available output voltage vectors, as well as the input sequences that give them rise, represented in the stationary Park reference plane. Concerning the induction machine characterization, an analytical study on the torque and stator flux instantaneous behavior is made, demonstrating that the first one highly depends on the delivered torque and speed. In consequence, a sampling scale predictive model of the induction machine is deduced in order to make possible the optimal choice of the inverter configuration for a sampling period. Finally, a DEADBEAT based control law is discussed and simulated as an illustration example of both the voltage-inverter and induction machine models presented within this paper.

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

1999-01-01

93

MultiLevel of Detail Models for Reverse Engineering in Remote CAD Systems  

Microsoft Academic Search

. This paper proposes a multi-level CAD system based on remote Reverse Engineering (RE). At the core of the system is an advanced\\u000a multi-Level Of Detail (LOD) representation for remote CAD systems. The LOD is represented through hierarchical nested bi-variant\\u000a surfaces. With the proposed multi-level approach, the entire RE takes tens of seconds for tens of thousands of sampled points.

A. Fischer

2002-01-01

94

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

E-print Network

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

Boning, Duane S.

95

Multi-hazards risk assessment at different levels  

NASA Astrophysics Data System (ADS)

Natural and technological disasters are becoming more frequent and devastating. Social and economic losses due to those events increase annually, which is definitely in relation with evolution of society. Natural hazards identification and analysis, as well natural risk assessment taking into account secondary technological accidents are the first steps in prevention strategy aimed at saving lives and protecting property against future events. The paper addresses methodological issues of natural and technological integrated risk assessment and mapping at different levels [1, 2]. At the country level the most hazardous natural processes, which may results in fatalities, injuries and economic loss in the Russian Federation, are considered. They are earthquakes, landslides, mud flows, floods, storms, avalanches. The special GIS environment for the country territory was developed which includes information about hazards' level and reoccurrence, an impact databases for the last 20 years, as well as models for estimating damage and casualties caused by these hazards. Federal maps of seismic individual and collective risk, as well as multi-hazards natural risk maps are presented. The examples of regional seismic risk assessment taking into account secondary accidents at fire, explosion and chemical hazardous facilities and regional integrated risk assessment are given for the earthquake prone areas of the Russian Federation. The paper also gives examples of loss computations due to scenario earthquakes taking into account accidents trigged by strong events at critical facilities: fire and chemical hazardous facilities, including oil pipe lines routes located in the earthquake prone areas. The estimations of individual seismic risk obtained are used by EMERCOM of the Russian Federation, as well as by other federal and local authorities, for planning and implementing preventive measures, aimed at saving lives and protecting property against future disastrous events. The results also allow to develop effective emergency response plans taking into account possible scenario events. Taking into consideration the size of the oil pipe line systems located in the highly active seismic zones, the results of seismic risk computation are used by TRANSNEFT JSC.

Frolova, N.; Larionov, V.; Bonnin, J.

2012-04-01

96

Two-Level Multi-Fidelity Design Optimization Studies for Supersonic Jets  

E-print Network

Two-Level Multi-Fidelity Design Optimization Studies for Supersonic Jets Seongim Choi , Juan J/preliminary design of superonic jet configurations requires multi-disciplinary analyses (MDAs) tools which are able-boom supersonic business jet. In this paper we extend our multi-fidelity approach to the design procedure

Alonso, Juan J.

97

Physics of polarized scattering at multi-level atomic systems  

E-print Network

The symmetric peak observed in linear polarization in the core of the solar sodium D$_1$ line at 5896 \\AA\\ has remained enigmatic since its discovery nearly two decades ago. One reason is that the theory of polarized scattering has not been experimentally tested for multi-level atomic systems in the relevant parameter domains, although the theory is continually being used for the interpretation of astrophysical observations. A laboratory experiment that was set up a decade ago to find out whether the D$_1$ enigma is a problem of solar physics or quantum physics revealed that the D$_1$ system has a rich polarization structure in situations where standard scattering theory predicts zero polarization, even when optical pumping of the $m$ state populations of the hyperfine-split ground state is accounted for. Here we show that the laboratory results can be modeled in great quantitative detail if the theory is extended to include the coherences in both the initial and final states of the scattering process. Radiat...

Stenflo, Jan

2015-01-01

98

A new multi-spectral feature level image fusion method for human interpretation  

Microsoft Academic Search

Various different methods to perform multi-spectral image fusion have been suggested, mostly on the pixel level. However, the jury is still out on the benefits of a fused image compared to its source images. We present here a new multi-spectral image fusion method, multi-spectral segmentation fusion (MSSF), which uses a feature level processing paradigm. To test our method, we compared

Marom Leviner; Masha Maltz

2009-01-01

99

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

100

MLS-SMIL for Electronic Surveillance of Facilities with Multi-Level Security Requirements  

E-print Network

MLS-SMIL for Electronic Surveillance of Facilities with Multi-Level Security Requirements 2 Naren surveillance, SMIL, Secure multimedia, XML Security, Multi level security 1. INTRODUCTION Electronic multimedia compositions. Our proposal is to integrate monitoring and communication in a secure surveillance

Farkas, Csilla

101

A Framework for Multi-Level Reliability Evaluation of Electrical Energy Systems  

E-print Network

research in the area, the impact on system operation, particularly in terms of reliability and performanceA Framework for Multi-Level Reliability Evaluation of Electrical Energy Systems Alejandro D. Dom@illinois.edu Abstract--This paper proposes a framework for multi-level reliability evaluation of electrical energy

Liberzon, Daniel

102

Feature level fusion of multi-instance finger knuckle print for person identification  

Microsoft Academic Search

The aim of this paper is to study the effect of feature level fusion of multi instances of finger knuckle prints. Initially, Zernike moments are extracted for a single instance of finger knuckle print of a person and study the identification accuracy. Subsequently, the effect of identification accuracy using feature level fusion of multi-instances of knuckle prints of a person

D. S. Guru; K. B. Nagasundara; S. Manjunath

2010-01-01

103

Emerging in between: The multi-level governance of renewable energy in the English regions  

Microsoft Academic Search

Analysis explains the emergence of a regional dimension to the multi-level governance of renewable energy in England. The case sits in a tense, yet informative, position between the two poles of ‘ordered’ and ‘messy’ multi-level governance. These tensions, which are currently debilitating, could be rendered more creative and fruitful if greater authority was devolved to the regions, and if policy

Adrian Smith

2007-01-01

104

A fully Bayesian approach for combining multi-level information in multi-state fault tree quantification  

Microsoft Academic Search

This paper presents a fully Bayesian approach that simultaneously combines non-overlapping (in time) basic event and higher-level event failure data in fault tree quantification with multi-state events. Such higher-level data often correspond to train, subsystem or system failure events. The fully Bayesian approach also automatically propagates the highest-level data to lower levels in the fault tree. A simple example illustrates

T. L. Graves; M. S. Hamada; R. Klamann; A. Koehler; H. F. Martz

2007-01-01

105

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

E-print Network

and Spain. Alberto Marzucchi & Sandro Montresor October 2012 Preliminary ­ Do not quote without prior, at the national and regional level (multi-level). An empirical application is carried out for Italy and Spain, while they show output additionality in Spain only, where they are also able to spur innovative

Sussex, University of

106

Cascade Multilevel Inverters for Utility Applications  

SciTech Connect

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

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

1997-12-31

107

MSPWM & MTPWM techniques for asymmetric H-bridge multilevel inverter  

Microsoft Academic Search

Multilevel inverter is a new breed of power converter which is suited for high power applications. The various topologies of multilevel inverter are diode - clamped, capacitor clamped and cascaded H-bridge inverter. It is an effective solution for increasing the number of levels in output waveform with reduced dc sources and switching elements, thereby dramatically reduces harmonics without increasing the

P. Jamuna; C. Christober Asir Rajan

2012-01-01

108

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

109

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

Microsoft Academic Search

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

Patrick Gaudreau; Marie-Claude Fecteau; Stéphane Perreault

2010-01-01

110

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

111

Multi-scale dynamic human fatigue detection with feature level fusion  

Microsoft Academic Search

Driver fatigue is a significant reason for many traffic accidents. We propose a novel multi-scale dynamic feature with feature level fusion for driver fatigue detection from facial image sequences. First, Gabor filters are employed to extract multi-scale and multi-orientation features from each image. Features of the same scale are then fused according to a fusion rule to produce a single

Xiao Fan; Yanfeng Sun; Baocai Yin

2008-01-01

112

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

SciTech Connect

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

Kromer, M.

2013-06-01

113

A multi-level frontal algorithm for finite element analysis and its implementation on parallel computation  

Microsoft Academic Search

This paper presents a multi-level frontal algorithm and its implementation and applications on parallel computation. A multi-frontal program is given which may be used for unsymmetric finite element matrix equations. The parallel program is developed on a cluster of workstations. The PVM (parallel virtual machine) system is used to handle communications among networked workstations. The method has advantages such as

Wang Xicheng; P. Baggio; B. A. Schrefler

1999-01-01

114

Architecture-level Thermal Behavioral Characterization For Multi-Core Microprocessors  

E-print Network

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

Tan, Sheldon X.-D.

115

Selective dorsal rhizotomy in children: comparison of outcomes after single-level versus multi-level laminectomy technique.  

PubMed

Children with cerebral palsy may experience spasticity, which may negatively impact their quality of life. One proven treatment for such spasticity is selective dorsal rhizotomy (SDR), whereby a partial sectioning of the dorsal roots from L2 to S1 is performed. SDR can be performed where the nerve root exits the intervertebral foramina via multi-level laminectomies, or at the level of the conus via a single-level laminectomy. At British Columbia Children's Hospital (BCCH), SDRs were performed via multi-level laminectomies until 2005, when the single-level technique was adopted. The single-level procedure is technically more challenging and takes longer, but requires a smaller incision and involves less muscle dissection. Functional outcomes at one-year follow-up are similar for the two methods of surgery. It was hypothesized that post-operative pain would be less, mobilization faster and hospital stay shorter using the single-level technique. Using a retrospective case series analysis, we compared nine patients who had had single-level SDR to 18 matched controls who had undergone SDR using the multi-level technique. There were no significant differences in post-operative pain, duration of opioid infusion, or time to mobilization. Length of hospital stay was significantly decreased after the single level procedure: 3.4 versus 5.2 days (p = 0.01). PMID:20865831

Ou, Christine; Kent, Sarah; Miller, Stacey; Steinbok, Paul

2010-01-01

116

GROUND WATER MONITORING AND SAMPLING: MULTI-LEVEL VERSUS TRADITIONAL METHODS ? WHAT?S WHAT?  

EPA Science Inventory

Recent studies have been conducted to evaluate different sampling techniques for determining VOC concentrations in groundwater. Samples were obtained using multi-level and traditional sampling techniques in three monitoring wells at the Raymark Superfund site in Stratford, CT. Ve...

117

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

E-print Network

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

Atiquzzaman, Mohammed

118

A multi-level filtering approach for fairing planar cubic B-spline curves  

Microsoft Academic Search

In this paper a new approach to the problem of fairing planar B-spline curves is introduced. We propose an algorithm based on a multi-level representation of cubic B-spline curves, which enables the identification of bad control points that need to be faired. The multi-level representation allows splitting a curve into its low resolution and details function parts. The details function

Giancarlo Amati

2007-01-01

119

Biomarker Identification by Knowledge-Driven MultiLevel ICA and Motif Analysis  

Microsoft Academic Search

Many statistical methods often fail to identify biologically meaningful biomarkers related to a specific disease under study from expression data alone. In this paper, we develop a novel strategy, namely knowledge-driven multi-level independent component analysis (ICA), to infer regulatory signals and identify biologically relevant biomarkers from microarray data. Specifically, based on multi-level clustering results and partial prior knowledge, we apply

Li Chen; Chen Wang; Ie-Ming Shih; Tian-Li Wang; Zhen Zhang; Yue Wang; Robert Clarke; Eric P. Hoffman; Jianhua Xuan

2007-01-01

120

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

E-print Network

UNIVERSITY OF CALGARY Context-Aware Personal Navigation Services Using Multi-level Sensor Fusion navigation. Context acquisition follows a feature-level recognition approach which includes preprocessing, and finding the most accurate context. The context reasoning technique uses a fuzzy decision-level fusion

Calgary, University of

121

A dual inverter based supercapacitor direct integration scheme for wind energy conversion systems  

Microsoft Academic Search

This paper presents a new direct integration scheme for supercapacitors that are used to mitigate short term power fluctuations in wind power systems. The proposed scheme uses the popular dual inverter topology for grid connection as well as interfacing a supercapacitor bank. The dual inverter system is formed by cascading two 2-level inverters named as the “main inverter” and the

S. D. G. Jayasinghe; D. M. Vilathgamuwa; U. K. Madawala

2010-01-01

122

Multi level land use surveys using remote sensing techniques  

Microsoft Academic Search

The use of Landsat imagery at 1:1 M and 1:250,000 and aerial photos on 1:65,000 and 1:20,000 scale have been used to study\\u000a landuse. It has been possible to achieve identification using Landsat imagery up to utility level ( level 1 and II ) and with\\u000a the aerial photographs further subdivisions of utility into management and identification (level III and

M. L. Manchanda; H. S. Iyer; B. M. Singh; Jitendra Prasad

1983-01-01

123

A latent-variable marginal method for multi-level incomplete binary data  

PubMed Central

Incomplete multi-level data arise commonly in many clinical trials and observational studies. Because of multi-level variations in this type of data, appropriate data analysis should take these variations into account. A random effects model can allow for the multi-level variations by assuming random effects at each level, but the computation is intensive because high-dimensional integrations are often involved in fitting models. Marginal methods such as the inverse probability weighted generalized estimating equations can involve simple estimation computation, but it is hard to specify the working correlation matrix for multi-level data. In this paper, we introduce a latent variable method to deal with incomplete multi-level data when the missing mechanism is missing at random, which fills the gap between the random effects model and marginal models. Latent variable models are built for both the response and missing data processes to incorporate the variations that arise at each level. Simulation studies demonstrate that this method performs well in various situations. We apply the proposed method to an Alzheimer’s disease study. PMID:22733392

Chen, Baojiang; Zhou, Xiao-Hua

2013-01-01

124

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

PubMed

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

Jung, Joo-Young; Moro, Munehito

2014-07-01

125

Integrated Inverter And Battery Charger  

NASA Technical Reports Server (NTRS)

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

Rippel, Wally E.

1988-01-01

126

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

127

Multi-leveled objects: color as a case study  

PubMed Central

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

Albertazzi, Liliana; Poli, Roberto

2014-01-01

128

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

129

GL074 Financial Summary with Management Level & Project Purpose (Excluding Agency and Multi-Year Funds)  

E-print Network

GL074 Financial Summary with Management Level & Project Purpose (Excluding Agency and Multi of the new filters found in the Cognos report GL074 Financial Summary with Management Level & Project Purpose Programs Management, Supply Chain, Budget/COA, and Monthly Financial. This report can be run by Manager

Shull, Kenneth R.

130

The multi-level fuzzy evaluation model of college students' comprehensive quality  

Microsoft Academic Search

This paper, according to the statistical data of a survey for nearly two thousand college students in a university, introduces the method of multi-level fuzzy comprehensive evaluation to make the criterion of students' comprehensive quality. Data from our survey indicate that comprehensive quality of college students is generally in a good level. Specifically, the results illustrate that the psychological adaptability

Zunqi Yang; Yuan Zhang; Rui Rong; Xu Zou

2010-01-01

131

Multi-phase permittivity reconstruction in electrical capacitance tomography by level-set methods  

Microsoft Academic Search

In this article, the numerical methods of reconstructing the permittivity profile of multi-phase material flow from data collected in electrical capacitance tomography (ECT) are presented. Under the assumption that multi-phase permittivity distributions are piecewise-constant functions, we develop iterative reconstruction algorithms by level-set methods that provide estimates for the interfaces and permittivity values simultaneously. Our formulation is based on the minimization

Weifu Fang

2007-01-01

132

An integrated multi-source JDL high-level fusion architecture using recombinant cognition synthesis  

Microsoft Academic Search

High-Level fusion systems based on the JDL model are relatively immature. Current solutions lack a comprehensive ability to manage multi-source data in a multi-dimensional vector space, and generally do not integrate collection to action models in a cohesive thread. Recombinant Cognition Synthesis (RCS) leverages best-of-breed techniques with a geospatial, temporal and semantic data model to provide a unified methodology that

Marco A. Solano; Stephen Ekwaro-Osire; Murat M. Tanik

2009-01-01

133

Characteristics of performance-optimal multi-level cache hierarchies  

Microsoft Academic Search

The increasing speed of new generation processors will exacerbate the already large difference between CPU cycle times and main memory access times. As this difference grows, it will be increasingly difficult to build single-level caches that are both fast enough to match these fast cycle times and large enough to effectively hide the slow main memory access times. One solution

Steven Przybylski; Mark Horowitz; John Hennessy

1989-01-01

134

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

135

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

136

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

NASA Astrophysics Data System (ADS)

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.

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

2013-01-01

137

Combined multi-gene analysis at the RNA and protein levels in single FFPE tissue sections.  

PubMed

Novel approaches of individualized medicine require rapid analyses of comprehensive multi-gene expression patterns both at the RNA and protein levels. Optimally these analyses are achieved with minimal amounts of tissues, which are derived from routine procedures of clinical diagnostics. We demonstrate the parallel analyses of gene expression of six different genes at the RNA and protein levels in two consecutive sections of routinely processed FFPE tissues. This was achieved by combination of multi-epitope-ligand cartography (MELC) and fully automatically magnetic bead-based RNA extraction and subsequent qRT-PCR analysis. Our work provides proof-of-principle that comprehensive analyses of multi-gene expression patterns can be achieved by the combination of these two high content technologies. This may provide new perspectives for the determination of pathogenic gene expression in the framework of individualized medicine. PMID:23583336

Ostalecki, Christian; Konrad, Andreas; Thurau, Elisabeth; Schuler, Gerold; Croner, Roland S; Pommer, Ansgar J; ael Stürzl, Mich

2013-08-01

138

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

139

Multi-focus and multi-level techniques for visualization and analysis of networks with thematic data  

NASA Astrophysics Data System (ADS)

Information-rich data sets bring several challenges in the areas of visualization and analysis, even when associated with node-link network visualizations. This paper presents an integration of multi-focus and multi-level techniques that enable interactive, multi-step comparisons in node-link networks. We describe NetEx, a visualization tool that enables users to simultaneously explore different parts of a network and its thematic data, such as time series or conditional probability tables. NetEx, implemented as a Cytoscape plug-in, has been applied to the analysis of electrical power networks, Bayesian networks, and the Enron e-mail repository. In this paper we briefly discuss visualization and analysis of the Enron social network, but focus on data from an electrical power network. Specifically, we demonstrate how NetEx supports the analytical task of electrical power system fault diagnosis. Results from a user study with 25 subjects suggest that NetEx enables more accurate isolation of complex faults compared to an especially designed software tool.

Cossalter, Michele; Mengshoel, Ole J.; Selker, Ted

2013-01-01

140

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

ERIC Educational Resources Information Center

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

Klosterman, Michelle L.; Sadler, Troy D.

2010-01-01

141

MODULAR MULTI-LEVEL CONVERTER BASED HVDC SYSTEM FOR GRID CONNECTION OF OFFSHORE WIND  

E-print Network

MODULAR MULTI-LEVEL CONVERTER BASED HVDC SYSTEM FOR GRID CONNECTION OF OFFSHORE WIND POWER PLANT U off-shore wind power plants. The MMC consists of a large number of simple voltage sourced converter offshore wind power plants (WPP) because they offer higher energy yield due to a superior wind profile

Chaudhary, Sanjay

142

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

143

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

E-print Network

1 Aiding multi-level decision-making processes for climate change mitigation and adaptation over policy, mitigation strategies and capacity for adaptation to climate change require construction Engineering and Geodezy, 1 Hr. Smirnenski blvd, 1046 Sofia, Bulgaria 6 Climate change and spatial development

Paris-Sud XI, Université de

144

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...

145

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

E-print Network

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

Möbius, Bernd

146

A Multi-Level Supporting Scheme for Face Recognition under Partial Occlusions and  

E-print Network

A Multi-Level Supporting Scheme for Face Recognition under Partial Occlusions and Disguise Jacky S, Hong Kong Abstract. Face recognition has always been a challenging task in real- life surveillance videos, with partial occlusion being one of the key factors affecting the robustness of face recognition

Wong, Kenneth K.Y.

147

Sonification of Images for the Visually Impaired using a Multi-Level Approach  

E-print Network

Sonification of Images for the Visually Impaired using a Multi-Level Approach Michael Banf & Volker presents a system that strives to give visually impaired persons direct perceptual access to images via, Design, Experimentation Keywords Sonification, Visually Impaired, Computer Vision, Machine Learning

Blanz, Volker

148

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

149

Fast and automatic processing of multi-level events in nanopore translocation experiments  

E-print Network

Fast and automatic processing of multi-level events in nanopore translocation experiments C events providing a novel and flexible tool for data analysis of nanopore experiments. Our program, called OpenNanopore, is based on the cumulative sums algorithm (CUSUM algorithm). This algorithm is an abrupt

Boyer, Edmond

150

Multi-level Attacks: an Emerging Security Concern for Cryptographic Hardware  

E-print Network

. INTRODUCTION To ease the computational burden of implementing complex cryptographic algorithms in securityMulti-level Attacks: an Emerging Security Concern for Cryptographic Hardware Sk. Subidh Ali, Rajat­44106, USA Email: skb21@case.edu Abstract--Modern hardware and software implementations of cryptographic

Bhunia, Swarup

151

SALTO A Versatile Multi-Level Annotation Tool Aljoscha Burchadt, Katrin Erk, Anette Frank  

E-print Network

SALTO ­ A Versatile Multi-Level Annotation Tool Aljoscha Burchadt, Katrin Erk, Anette Frank Saarbr¨ucken, Germany {albu, erk, frank, kowalski, pado}@coli.uni-sb.de Abstract In this paper, we (Mengel and Lez- ius, 2000) as well as its own output format, SALSA/TIGER XML (Erk and Pado, 2004). TIGER

Padó, Sebastian

152

A new classification of higher level gait disorders in patients with cerebral multi-infarct states  

Microsoft Academic Search

Background: cerebral multi-infarct states may lead to gait disorders in the absence of cognitive impairment. Where these gait disorders occur in the absence of neurological signs they have been termed gait apraxia or more recently higher-level gait disorders. In this paper we hypothesise three main types based on presumptive sites of anatomical damage: (a) Ignition Apraxia, where damage is predominantly

RICHARD LISTON; J ANE MICKELBOROUGH; J ACQUELINE BENE; R AYMOND TALLIS

2003-01-01

153

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 simultaneously based on molecular data alone. These signatures were based on a new method reported herein

Geman, Donald

154

Graduate Attribute Attainment in a Multi-Level Undergraduate Geography Course  

ERIC Educational Resources Information Center

We investigated students' perceptions of graduate attributes in a multi-level (second and third year) geography course. A case study with mixed methodology was employed, with data collected through focus groups and a survey. We found that undergraduate geography students can identify the skills, knowledge and attributes that are developed…

Mager, Sarah; Spronken-Smith, Rachel

2014-01-01

155

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

156

Multi-Period Network Interdiction Problems with Applications to City-Level Drug Enforcement  

Microsoft Academic Search

We consider a new class of multi-period network interdiction problems that focus on scheduling the activities of law enforcement in order to successfully interdict criminals in an illegal drug supply chain. This class of problems possesses several novel features for interdiction problems that were motivated through collaborations with city-level drug enforcement officials. These features include modeling the temporal aspects of

Ajay Malaviya; Chase Rainwater; Thomas C. Sharkey

2011-01-01

157

Multi-period network interdiction problems with applications to city-level drug enforcement  

Microsoft Academic Search

This article considers a new class of multi-period network interdiction problems that focus on scheduling the activities of law enforcement in order to successfully interdict criminals in an illegal drug supply chain. This class of problems possesses several novel features for interdiction problems that were motivated through collaborations with city-level drug enforcement officials. These features include modeling the temporal aspects

Ajay Malaviya; Chase Rainwater; Thomas Sharkey

2012-01-01

158

Multi-Level Partnerships Support a Comprehensive Faith-Based Health Promotion Program  

ERIC Educational Resources Information Center

This article examines the role of multi-level partnerships in implementing Faithful Families Eating Smart and Moving More, a faith-based health promotion program that works with low-resource faith communities in North Carolina. This program incorporates a nine-lesson individual behavior change program in concert with policy and environmental…

Hardison-Moody, Annie; Dunn, Carolyn; Hall, David; Jones, Lorelei; Newkirk, Jimmy; Thomas, Cathy

2011-01-01

159

Report no. 06/03 Multi-level Monte Carlo path simulation  

E-print Network

, with other variance reduction methods such as stratified sampling [5] and quasi Monte Carlo methods [11, 12 in Y due to the Monte Carlo sampling, and the second term comes from the O(h) bias introduced ) through the use of a multi-level method which reduces the variance, leaving unchanged the bias due

Giles, Mike

160

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.

161

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

162

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

163

Residential satisfaction in housing estates in European cities: a multi-level approach  

Microsoft Academic Search

This paper mainly focuses on the determinants of housing and estate satisfaction in\\u000apost-Second World War housing estates. Multi-level linear regression models were applied to\\u000aestimate the impacts of individual, dwelling and estate characteristics on resident satisfaction levels,\\u000ausing a unique dataset from 25 post-Second World War estates in nine European countries. It is\\u000aconcluded that satisfaction with the dwelling

K. K. Dekker; S. de Vos; S. Musterd; R. van Kempen

2011-01-01

164

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

PubMed

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

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

2015-01-14

165

An adaptive multi-level simulation algorithm for stochastic biological systems  

NASA Astrophysics Data System (ADS)

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

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

2015-01-01

166

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

167

TEACHING SCIENCE | VOLUME 51 NO 1 | pp 28-31 Introduction to relativity: a multi-level, multi-media resource.  

E-print Network

1 TEACHING SCIENCE | VOLUME 51 NO 1 | pp 28-31 Introduction to relativity: a multi-level, multi Relativity, which poses conceptual problems and the difficulty that few of its effects may be directly of the main aspects of special relativity, on the other hand, require only a modest background of other

New South Wales, University of

168

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

169

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

170

Optimal load balancing leveling method for multi-leg flexible platforms  

NASA Astrophysics Data System (ADS)

The working platforms supported with multiple extensible legs must be leveled before they come into operation. Although the supporting stiffness and reliability of the platform are improved with the increasing number of the supporting legs, the increased overdetermination of the multi-leg platform systems leads to leveling coupling problem among legs and virtual leg problem in which some of the supporting legs bear zero or quasi zero loads. These problems make it quite complex and time consuming to level such a multi-leg platform. Based on rigid body kinematics, an approximate equation is formulated to rapidly calculate the leg extension for leveling a rigid platform, then a proportional speed control strategy is proposed to reduce the unexpected platform distortion and leveling coupling between supporting legs. Taking both the load coupling between supporting legs and the elastic flexibility of the working platform into consideration, an optimal balancing legs’ loads(OBLL) model is firstly put forward to deal with the traditional virtual leg problem. By taking advantage of the concept of supporting stiffness matrix, a coupling extension method(CEM) is developed to solve this OBLL problem for multi-leg flexible platform. At the end, with the concept of supporting stiffness matrix and static transmissibility matrix, an optimal load balancing leveling method is proposed to achieve geometric leveling and legs’ loads balancing simultaneously. Three numerical examples are given out to illustrate the performance of proposed methods. This paper proposes a method which can effectively quantify all of the legs’ extension at the same time, achieve geometric leveling and legs’ loads balancing simultaneously. By using the proposed methods, the stability, precision and efficiency of auto-leveling control process can be improved.

Gang, Xianyue; Chai, Shan

2013-09-01

171

STEPS: Going beyond the tip of the iceberg. A multi-level, multipurpose approach to common mental health problems  

Microsoft Academic Search

STEPS is a primary care mental health team that has attempted to develop a very high volume multi-level, multi-purpose service for those with mild to moderate problems. The service attempts to overcome many of the limitations of more traditional services. This paper describes the services contained within the six level model.

Jim White; A Joice; S Petrie; S Johnston; D Gilroy; P Hutton; N Hynes

2008-01-01

172

Options for future effective water management in Lombok: A multi-level nested framework  

NASA Astrophysics Data System (ADS)

Previous research on water use in Lombok identified reduced water available in springs and limits on seasonal water availability. It foreshadowed increasing competition for water resources in critical areas of Lombok. This study examines preliminary information on local social-institutional arrangements for water allocation in the context of Ostrom's rules for self-governing institutions. We identify robust customary mechanisms for decision-making about water sharing and rules at a local level and suggest areas of further investigation for strengthening multi-level networked and nested frameworks, in collaboration with higher levels of government.

Sjah, Taslim; Baldwin, Claudia

2014-11-01

173

Modeling and simulation of multilevel current source inverter based on SIMetrix/SIMPLIS  

NASA Astrophysics Data System (ADS)

Based on analysis of operational principle of single-phase multilevel current source inverter (MCSI), a novel method for modeling and simulation of MCSI system was proposed. In SIMetrix/SIMPLIS, the simulation model of a kind of singlephase 5-level CSI was developed by using hierarchy design. In the control system, the multi-carrier PWM modulation strategy was adopted, the current balance control for intermediate DC-link inductor was implemented on the principle of redundant switching combinations. The reasonability and validity were testified by the coincidence of the simulation results and theoretical analysis. This novel method is also suitable for modeling other power electronics inverters and offers a new thinking for designing actual power electronic circuits.

Bao, Jianyu; Bao, Weibing; Fang, Weizhong; Ma, Xiushui

2010-12-01

174

Modeling and simulation of multilevel current source inverter based on SIMetrix/SIMPLIS  

NASA Astrophysics Data System (ADS)

Based on analysis of operational principle of single-phase multilevel current source inverter (MCSI), a novel method for modeling and simulation of MCSI system was proposed. In SIMetrix/SIMPLIS, the simulation model of a kind of singlephase 5-level CSI was developed by using hierarchy design. In the control system, the multi-carrier PWM modulation strategy was adopted, the current balance control for intermediate DC-link inductor was implemented on the principle of redundant switching combinations. The reasonability and validity were testified by the coincidence of the simulation results and theoretical analysis. This novel method is also suitable for modeling other power electronics inverters and offers a new thinking for designing actual power electronic circuits.

Bao, Jianyu; Bao, Weibing; Fang, Weizhong; Ma, Xiushui

2011-05-01

175

Noise-Assisted Quantum Electron Transfer in Multi-Level Donor-Acceptor System  

E-print Network

We analytically and numerically study noise-assisted quantum electron transfer (ET) in bio-complexes consisting of a single-level electron donor and an acceptor which is modeled by many electron energy levels. Interactions are included between the donor and the acceptor energy levels and with the protein environment, which is modeled by a diagonal classical noise acting on all donor and acceptor energy levels. Different regions of parameters characterizing (i) the number of the acceptor levels, (ii) the acceptor "band-width", and (iii) the amplitude of noise and its correlation time are considered. Under some conditions, we derive analytical expressions for the ET rate and efficiency, which reveal the coarse-grain features. We obtain equal occupation of all levels at large times, independently of the structure of the acceptor band. We discuss the multi-scale regime of the acceptor population, and the accompanying effect of quantum coherent oscillations, which are analogous to those observed in experiments on ...

Gurvitz, Shmuel; Berman, Gennady P

2014-01-01

176

Program Predicts Nonlinear Inverter Performance  

NASA Technical Reports Server (NTRS)

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

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

1985-01-01

177

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

178

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

179

[Study on multi-level fractal features extraction method of breast mass].  

PubMed

Breast mass is women's common disease, and it seriously affects the health of women. Accurate detection and location of the mass will greatly improve the precision of the diagnosis of the breast disease. Studies have shown that the organizational structure and surface roughness of the mass constitute the texture features of mass and it is an important basis for distinguishing the mass. In this paper, a multi-level fractal features extraction method is proposed, and, moreover, the fractal feature vector of the suspicious lesions has been established, thus realizing the feature extraction and analysis of the mammary gland. Finally, the result of classification with the support vector machine (SVM) was given. 110 mammograms are extracted and classified with an accuracy of 90%. The results showed that the multi-level fractal features extraction and classification methods proposed in this paper could improve the accuracy of mass detection and could be effective for the early diagnosis of the disease. PMID:23858747

Ke, Li; Zhang, Xue; Kang, Yan

2013-04-01

180

Integral inverter/battery charger for use in electric vehicles  

NASA Technical Reports Server (NTRS)

The design and test results of a thyristor based inverter/charger are discussed. A battery charger is included integral to the inverter by using a subset of the inverter power circuit components. The resulting charger provides electrical isolation between the vehicle propulsion battery and ac line and is capable of charging a 25 kWh propulsion battery in 8 hours from a 220 volt ac line. The integral charger employs the inverter commutation components at a resonant ac/dc isolated converter rated at 3.6 kW. Charger efficiency and power factor at an output power of 3.6 kW are 86% and 95% respectively. The inverter, when operated with a matching polyphase ac induction motor and nominal 132 volt propulsion battery, can provide a peak shaft power of 34 kW (45 ph) during motoring operation and 45 kW (60 hp) during regeneration. Thyristors are employed for the inverter power switching devices and are arranged in an input-commutated topology. This configuration requires only two thyristors to commutate the six main inverter thyristors. Inverter efficiency during motoring operation at motor shaft speeds above 450 rad/sec (4300 rpm) is 92-94% for output power levels above 11 KW (15 hp). The combined ac inverter/charger package weighs 47 kg (103 lbs).

Thimmesch, D.

1983-01-01

181

A framework for meta-level control in multi-agent systems  

Microsoft Academic Search

Sophisticated agents operating in open environments must make decisions that efficiently trade off the use of their limited resources between dynamic deliberative actions and domain actions. This is the meta-level control problem for agents operating in resource-bounded multi-agent environments. Con- trol activities involve decisions on when to invoke and the amount to effort to put into scheduling and coordination of

Anita Raja; Victor R. Lesser

2007-01-01

182

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

SciTech Connect

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

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

1989-12-31

183

MultiLevel Fuzzy Comprehensive Evaluation on the Process of University Students' E-Learning  

Microsoft Academic Search

Evaluating the process of university students' elearning scientifically is full of academic and practical significance. The thesis constructs an evaluating indicator system on the process of university students' e-learning based on the learning attitude, communication and cooperation as well as resources used. It also establishes a multi-level fuzzy comprehensive evaluating model by applying the fuzzy-math theory, and verifies the effectiveness

Yi-nan Su

2009-01-01

184

Scheduling mixed-model multi-level just-in-time production systems  

Microsoft Academic Search

Many companies are converting their mixed-model multi-level production systems to just-in-time systems. This requires reducing set-up times so that small-lot production can be run. In this paper a theoretical basis is developed for scheduling these systems, and scheduling algorithms and heuristics are developed. The only other known scheduling method (the goal-chasing method), developed and used by Toyota, is shown to

JOHN MILTENBURG; GORDON SINNAMON

1989-01-01

185

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

Microsoft Academic Search

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

Benjamin Blatt; Larrie Greenberg

2007-01-01

186

Investigating the Structure and Process of Academic Emphasis on Student Achievement: A Multi-Level Analysis  

E-print Network

is thank you and I love you. Finally, I would like to acknowledge the love and support of Tera and Caitlin. Tera has done more than any wife should ever be expected to do in a marriage. She was with me every step of the way. Caitlin always reminded me....15 Unconditional Model Reading Achievement.......................................... 82 Table 4.16 Multi-level Analysis Predicting Math Achievement Model 1................ 86 Table 4.17 Stepwise Backward Elimination Table (Math...

Barron, James Bakewell

2014-04-17

187

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

188

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

2013-01-01

189

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

190

Rehabilitation of a patient with a rare multi-level isthmic spondylolisthesis: a case report  

PubMed Central

A rare multi–level isthmic spondylolisthesis was discovered in a young male patient following an acute onset of low back pain. The prevalence of spondylolisthesis in the adult population is low and it is believed that the prevalence of multiple level spondylolisthesis is even rarer. A combination of onset of ambulation, hereditary factors, and sports involving hyper-extension of the spine are predisposing factors. Conservative treatment such as chiropractic manipulation and rehabilitation of the spine are first treatment options before surgical intervention is considered. The clinical presentations, radiographic features, treatment options including rehabilitation methods are discussed. PMID:17549226

Wong, Leong C

2004-01-01

191

An integrated multi-source JDL high-level fusion architecture using recombinant cognition synthesis  

NASA Astrophysics Data System (ADS)

High-Level fusion systems based on the JDL model are relatively immature. Current solutions lack a comprehensive ability to manage multi-source data in a multi-dimensional vector space, and generally do not integrate collection to action models in a cohesive thread. Recombinant Cognition Synthesis (RCS) leverages best-of-breed techniques with a geospatial, temporal and semantic data model to provide a unified methodology that recombines multi-source data with analytic and predictive algorithms to synthesize actionable intelligence. This architecture framework enables the traversal of entity relationships at different level of granularities and the discovery of latent knowledge, thereby facilitating the domain problem analysis and the development of a Course-of-Action to mitigate adversarial threats. RCS also includes process refinement techniques to achieve superior information dominance, by incorporating specialized metadata. This comprehensive and unified methodology delivers enhanced utility to the intelligence analyst, and addresses key issues of relevancy, timeliness, accuracy, and uncertainty by providing metrics via feedback loops within the RCS infrastructure that augment the efficiency and effectiveness of the end-to-end fusion processing chain.

Solano, Marco A.; Ekwaro-Osire, Stephen; Tanik, Murat M.

2009-04-01

192

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

PubMed

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

Fox, John R E; Power, Michael J

2009-01-01

193

This document is a preprint of the final paper: B. Sun, F. Wu, T. Dragicevic, J. M. Guerrero, and J. C. Vasquez, "A single phase seven-level grid-connected inverter based on three reference  

E-print Network

order harmonics. The multilevel converters which could offer a small voltage steps and high resolution acoustic noise, multi-level converter attracts more and more attentions[3]. At present, Neutral Point diode-clamped [4], flying capacitor [5] and cascaded H-bridge [6] are applied commonly. Among them, the diode

Vasquez, Juan Carlos

194

Simulation of organic inverter  

NASA Astrophysics Data System (ADS)

Pentacene and N,N'-ditridecylperylene-3,4,9,10-tetracarboxylic diimide (PTCDI-C13H27) have been used as organic semiconductors for the fabrication of p-type and n-type organic thin-film transistors (OTFTs). Both types of semiconductors are well-established and demonstrate good performance in single devices, but few competitive results have been reported in complementary circuits. In this manuscript, we show the fabrication, electrical characterization and simulation of an organic complementary inverter using pentacene and PTCDI-C13 as active semiconductors. Simulation was done using a model with physical aspects. We report good fitting of p-type and n-type parameters for the OTFT model and good results for DC transfer characteristics of the organic complementary inverter. The fitting of the parameters of the OTFT model is performed using an optimized parameter extraction technique which is using fuzzy logic to adjust the parameters to its optimal value.

Papadopoulos, N. P.; Marsal, A.; Picos, R.; Puigdollers, J.; Hatzopoulos, A. A.

2012-02-01

195

Parallel of low-level computer vision algorithms on a multi-DSP system  

NASA Astrophysics Data System (ADS)

Parallel hardware becomes a commonly used approach to satisfy the intensive computation demands of computer vision systems. A multiprocessor architecture based on hypercube interconnecting digital signal processors (DSPs) is described to exploit the temporal and spatial parallelism. This paper presents a parallel implementation of low level vision algorithms designed on multi-DSP system. The convolution operation has been parallelized by using redundant boundary partitioning. Performance of the parallel convolution operation is investigated by varying the image size, mask size and the number of processors. Experimental results show that the speedup is close to the ideal value. However, it can be found that the loading imbalance of processor can significantly affect the computation time and speedup of the multi- DSP system.

Liu, Huaida; Jia, Pingui; Li, Lijian; Yang, Yiping

2011-06-01

196

Low-power multi-chip module and board-level links for data transfer  

SciTech Connect

Advanced device technologies such as Vertical Cavity Surface-Emitting Lasers (VCSELs) and diffractive micro lenses can be obtained with novel packaging techniques to allow low-power interconnection of parallel optical signals. These interconnections can be realized directly on circuit boards, in a multi-chip module format, or in packages that emulate electrical connectors. For applications such as stacking of Multi-Chip Module (MCM) layers, the links may be realized in bi-directional form using integrated diffractive microlenses. In the stacked MCM design, consumed electrical power is minimized by use of a relatively high laser output from high efficiency VCSELs, and a receiver design that is optimized for low power, at the expense of dynamic range. Within certain constraints, the design may be extended to other forms such as board-level interconnects.

Carson, R.F.; Hardin, T.L.; Warren, M.E.; Lear, K.L.; Lovejoy, M.L.; Seigal, P.K.; Craft, D.C. [Sandia National Labs., Albuquerque, NM (United States); Enquist, P.J. [Research Triangle Inst., Research Triangle Park, NC (United States)

1997-03-01

197

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

198

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

ERIC Educational Resources Information Center

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

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

2010-01-01

199

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

200

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

PubMed Central

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

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

2015-01-01

201

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

202

Improved multi-level protein–protein interaction prediction with semantic-based regularization  

PubMed Central

Background Protein–protein interactions can be seen as a hierarchical process occurring at three related levels: proteins bind by means of specific domains, which in turn form interfaces through patches of residues. Detailed knowledge about which domains and residues are involved in a given interaction has extensive applications to biology, including better understanding of the binding process and more efficient drug/enzyme design. Alas, most current interaction prediction methods do not identify which parts of a protein actually instantiate an interaction. Furthermore, they also fail to leverage the hierarchical nature of the problem, ignoring otherwise useful information available at the lower levels; when they do, they do not generate predictions that are guaranteed to be consistent between levels. Results Inspired by earlier ideas of Yip et al. (BMC Bioinformatics 10:241, 2009), in the present paper we view the problem as a multi-level learning task, with one task per level (proteins, domains and residues), and propose a machine learning method that collectively infers the binding state of all object pairs. Our method is based on Semantic Based Regularization (SBR), a flexible and theoretically sound machine learning framework that uses First Order Logic constraints to tie the learning tasks together. We introduce a set of biologically motivated rules that enforce consistent predictions between the hierarchy levels. Conclusions We study the empirical performance of our method using a standard validation procedure, and compare its performance against the only other existing multi-level prediction technique. We present results showing that our method substantially outperforms the competitor in several experimental settings, indicating that exploiting the hierarchical nature of the problem can lead to better predictions. In addition, our method is also guaranteed to produce interactions that are consistent with respect to the protein–domain–residue hierarchy. PMID:24725682

2014-01-01

203

Building obesity in Canada: understanding the individual- and neighbourhood-level determinants using a multi-level approach.  

PubMed

The objective of this paper was to identify heterogeneities associated with the relationships between the body mass index (BMI) and individual as well as socio-environmental correlates at the individual- and area-levels. The data sources used were: (i) the 2003 Canadian Community Health Survey; (ii) the 2001 Canadian Census; and (iii) the Enhanced Points of Interest (EPOI) database from the Desktop Mapping Technologies Inc. Participants were adults (?20 years; n = 12,836; based on a survey weight scheme Nweighted = 5,418,218) from Toronto and Vancouver census metropolitan areas with no missing BMI records. In addition to conventional 1 km-buffers, we constructed activity-space-buffers to better assess the walkability and potentially increased BMI of individuals. Multi-level analysis was then applied to estimate the relative effects of both individual- and area-level risk-factors for increased BMI. The findings demonstrate a negative association between BMI and energy expenditure, mixed land uses, residential density and average value of dwellings, while a positive association was found with low educational attainment. Relationships were independent of individual characteristics such as age and ethnicity. Although the majority of the variation in these outcomes was found to be due to individual-level differences, this study did show significant differences at the area-level as well. The activity-space-buffers presented a vast improvement compared to the conventional 1 km-buffers. The results presented support the rationale that targeting high-risk individuals will only address a portion of the increasing BMI problem; it is essential to also address the characteristics of places that compel individuals to make unhealthy choices. PMID:25545925

Pouliou, Theodora; Elliott, Susan J; Paez, Antonio; Newbold, K Bruce

2014-11-01

204

Dynamic performance and control of a static var generator using cascade multilevel inverters  

SciTech Connect

A cascade multilevel inverter is proposed for static VAR shifting, compensation/generation applications. The new cascade 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. It can eliminate the need for transformers in multipulse inverters. A prototype static VAR generator (SVG) system using 11- level cascade inverter (21-level line-to-line voltage waveform) has been built. The output voltage waveform is equivalent to that of a 60- pulse inverter. This paper focuses on dynamic performance of the cascade inverter based SVG system. Control schemes are proposed to achieve a fast response which is impossible for a conventional static VAR compensator (SVC). Analytical, simulated and experimental results show the superiority of the proposed SVG system.

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

1996-10-01

205

Automatic detection of multi-level acetowhite regions in RGB color images of the uterine cervix  

NASA Astrophysics Data System (ADS)

Uterine cervical cancer is the second most common cancer among women worldwide. Colposcopy is a diagnostic method used to detect cancer precursors and cancer of the uterine cervix, whereby a physician (colposcopist) visually inspects the metaplastic epithelium on the cervix for certain distinctly abnormal morphologic features. A contrast agent, a 3-5% acetic acid solution, is used, causing abnormal and metaplastic epithelia to turn white. The colposcopist considers diagnostic features such as the acetowhite, blood vessel structure, and lesion margin to derive a clinical diagnosis. STI Medical Systems is developing a Computer-Aided-Diagnosis (CAD) system for colposcopy -- ColpoCAD, a complex image analysis system that at its core assesses the same visual features as used by colposcopists. The acetowhite feature has been identified as one of the most important individual predictors of lesion severity. Here, we present the details and preliminary results of a multi-level acetowhite region detection algorithm for RGB color images of the cervix, including the detection of the anatomic features: cervix, os and columnar region, which are used for the acetowhite region detection. The RGB images are assumed to be glare free, either obtained by cross-polarized image acquisition or glare removal pre-processing. The basic approach of the algorithm is to extract a feature image from the RGB image that provides a good acetowhite to cervix background ratio, to segment the feature image using novel pixel grouping and multi-stage region-growing algorithms that provide region segmentations with different levels of detail, to extract the acetowhite regions from the region segmentations using a novel region selection algorithm, and then finally to extract the multi-levels from the acetowhite regions using multiple thresholds. The performance of the algorithm is demonstrated using human subject data.

Lange, Holger

2005-04-01

206

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

207

Noise reduction by combining smearing with multi-level integration methods  

NASA Astrophysics Data System (ADS)

In this paper, we propose an algorithm that combines the Lüscher-Weiss (LW) multi-level error reduction technique with three-dimensional gauge-field smoothing. The purpose of this algorithm is to reduce the noise and the computational time associated with measuring field correlators in the low temperature pure quantum chromodynamics (QCD), or the stringy regions of Yang-Mills theory in general. The simultaneous application of both link-blocking and path-integral factorization techniques is based on the observation that Monte Carlo updating of the three-dimensional smeared lattices preserves the key features of the long distance physics.

Bakry, Ahmed S.; Chen, Xurong; Zhang, Pengming

2014-07-01

208

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

PubMed

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

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

2013-10-01

209

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

SciTech Connect

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

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

1997-08-01

210

ULC: A File Block Placement and Replacement Protocol to Effectively Exploit Hierarchical Locality in MultiLevel Buffer Caches  

Microsoft Academic Search

In a large client\\/server cluster system, file blocks are cached in a multi-level storage hierarchy. Existing file block placement and replacement are either conducted on each level of the hierarchy independently, or by applying an LRU policy on more than one levels. One major limitation of these schemes is that hierarchical locality of file blocks with non- uniform strengths is

Song Jiang; Xiaodong Zhang

2004-01-01

211

Noise-Assisted Quantum Electron Transfer in Multi-Level Donor-Acceptor System  

E-print Network

We analytically and numerically study noise-assisted quantum electron transfer (ET) in bio-complexes consisting of a single-level electron donor and an acceptor which is modeled by many electron energy levels. Interactions are included between the donor and the acceptor energy levels and with the protein environment, which is modeled by a diagonal classical noise acting on all donor and acceptor energy levels. Different regions of parameters characterizing (i) the number of the acceptor levels, (ii) the acceptor "band-width", and (iii) the amplitude of noise and its correlation time are considered. Under some conditions, we derive analytical expressions for the ET rate and efficiency, which reveal the coarse-grain features. We obtain equal occupation of all levels at large times, independently of the structure of the acceptor band. We discuss the multi-scale regime of the acceptor population, and the accompanying effect of quantum coherent oscillations, which are analogous to those observed in experiments on exciton dynamics in photosynthetic complexes. We also demonstrate that, for a relatively wide acceptor band, the efficiency of ET from donor to acceptor can be close to 100% for a broad range of noise amplitudes, for both sharp and flat redox potentials.

Shmuel Gurvitz; Alexander I. Nesterov; Gennady P. Berman

2014-04-23

212

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

213

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

214

Gas cooled traction drive inverter  

DOEpatents

The present invention provides a modular circuit card configuration for distributing heat among a plurality of circuit cards. Each circuit card includes a housing adapted to dissipate heat in response to gas flow over the housing. In one aspect, a gas-cooled inverter includes a plurality of inverter circuit cards, and a plurality of circuit card housings, each of which encloses one of the plurality of inverter cards.

Chinthavali, Madhu Sudhan

2013-10-08

215

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

216

Medical Image Segmentation Using Modified Level-Set Model with Multi-Scale Gradient* Vector Flow  

NASA Astrophysics Data System (ADS)

This paper presents a novel method for medical image segmentation that can detect the edges or boundaries of all target objects(defined as high intensity regions) in an image by integrating multi-scale gradient* vector flow(MGVF) into a modified level-set model. The MGVF uses multi-scale images and the gradient of gradient magnitude of a scaled image to generate a vector flow field. This vector flow field is then substituted into a corresponding partial differential equation(PDE) of a modified level-set model that represents the active contour. The proposed method can effectively pull the active contour to attach to the boundary of each target object in an image, especially the boundary of an object that is very close to another object and the boundary of an object with low gradient magnitude. The experiments were tested on 1600 two dimensional CT scan images and the results have shown that the proposed method can accurately detect the boundaries of bones, colons, and residuals inside the colons.

Lipikorn, Rajalida; Chunhapongpipat, Krisorn; Sirisup, Sirod; Boonklurb, Ratinan; Cooharojananone, Nagul

217

Fabricating a multi-level barrier-integrated microfluidic device using grey-scale photolithography  

NASA Astrophysics Data System (ADS)

Most polymer-replica-based microfluidic devices are mainly fabricated by using standard soft-lithography technology so that multi-level masters (MLMs) require multiple spin-coatings, mask alignments, exposures, developments, and bakings. In this paper, we describe a simple method for fabricating MLMs for planar microfluidic channels with multi-level barriers (MLBs). A single photomask is necessary for standard photolithography technology to create a polydimethylsiloxane grey-scale photomask (PGSP), which adjusts the total amount of UV absorption in a negative-tone photoresist via a wide range of dye concentrations. Since the PGSP in turn adjusts the degree of cross-linking of the photoresist, this method enables the fabrication of MLMs for an MLB-integrated microfluidic device. Since the PGSP-based soft-lithography technology provides a simple but powerful fabrication method for MLBs in a microfluidic device, we believe that the fabrication method can be widely used for micro total analysis systems that benefit from MLBs. We demonstrate an MLB-integrated microfluidic device that can separate microparticles.

Nam, Yoonkwang; Kim, Minseok; Kim, Taesung

2013-10-01

218

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

219

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

220

Multi-Level Interval Estimation for Locating damage in Structures by Using Artificial Neural Networks  

SciTech Connect

A new analysis technique, called multi-level interval estimation method, is developed for locating damage in structures. In this method, the artificial neural networks (ANN) analysis method is combined with the statistics theory to estimate the range of damage location. The ANN is multilayer perceptron trained by back-propagation. Natural frequencies and modal shape at a few selected points are used as input to identify the location and severity of damage. Considering the large-scale structures which have lots of elements, multi-level interval estimation method is developed to reduce the estimation range of damage location step-by-step. Every step, estimation range of damage location is obtained from the output of ANN by using the method of interval estimation. The next ANN training cases are selected from the estimation range after linear transform, and the output of new ANN estimation range of damage location will gained a reduced estimation range. Two numerical example analyses on 10-bar truss and 100-bar truss are presented to demonstrate the effectiveness of the proposed method.

Pan Danguang; Gao Yanhua; Song Junlei [School of Civil and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083 (China)

2010-05-21

221

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

222

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 Marshall Space Flight Center (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 fiom 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 HMC-IRA design has completed all engineering and deliverable unit testing. P

Robertson, Bryan A.; Wilkerson, Delisa

2005-01-01

223

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

PubMed Central

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

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

2014-01-01

224

Extinction Dynamics and Evolution of a Survivability-Based Multi-Level Food-Web Model  

NASA Astrophysics Data System (ADS)

A multi-level evolution model where forced extinctions occur throughout the system based on a species fitness value (or survivability) is developed that is essentially the fusion of the evolution model of Bak and Sneppen and the food-web model of Amaral and Meyer. This model is found to describe the fossil record and behave as a self-organized critical system with a power law exponent of approximately 2, but is also found to be remarkably similar to a model that causes the forced extinctions randomly throughout the system. To explain this result we show that fitness is nearly randomly distributed with a slight peak in forced extinction (due to fitness) in the middle levels. These findings lend strong support to the hypothesis that coextinction effects (propagated through a food-web) provide a robust explanation of the fossil record, independent of the mechanism for species competition.

Berger, B. W.; Boulter, C. J.

225

Unprotected sex among heterosexually active homeless men: results from a multi-level dyadic analysis.  

PubMed

HIV is a serious public health problem for homeless populations. Homeless men who have sex with women have received less attention in the HIV risk literature than other homeless populations. This research uses multi-level modeling to investigate the context of unprotected sex among heterosexually active homeless men in the Skid Row area of Los Angeles. Based on interviews with 305 randomly selected men who discussed 665 of their recent female sexual relationships, this project investigates the correlates of unprotected sex during the past 6 months at the partnership, individual, and social network levels. Several different measures of relationship closeness and lack of communication about HIV/condoms were associated with unprotected sex. Controlling for relationship factors, men's negative attitudes towards condoms, mental health, and higher number of male sex partners also were associated with having unprotected sex with female partners. We discuss the implications of these findings for health interventions. PMID:23212852

Kennedy, David P; Wenzel, Suzanne L; Brown, Ryan; Tucker, Joan S; Golinelli, Daniela

2013-06-01

226

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

227

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

NASA Astrophysics Data System (ADS)

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

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

2011-12-01

228

Automatic multi-organ segmentation using learning-based segmentation and level set optimization.  

PubMed

We present a novel generic segmentation system for the fully automatic multi-organ segmentation from CT medical images. Thereby we combine the advantages of learning-based approaches on point cloud-based shape representation, such a speed, robustness, point correspondences, with those of PDE-optimization-based level set approaches, such as high accuracy and the straightforward prevention of segment overlaps. In a benchmark on 10-100 annotated datasets for the liver, the lungs, and the kidneys we show that the proposed system yields segmentation accuracies of 1.17-2.89 mm average surface errors. Thereby the level set segmentation (which is initialized by the learning-based segmentations) contributes with an 20%-40% increase in accuracy. PMID:22003717

Kohlberger, Timo; Sofka, Michal; Zhang, Jingdan; Birkbeck, Neil; Wetzl, Jens; Kaftan, Jens; Declerck, Jérôme; Zhou, S Kevin

2011-01-01

229

A Multi-Level Model of Information Seeking in the Clinical Domain  

PubMed Central

Objective: Clinicians often have difficulty translating information needs into effective search strategies to find appropriate answers. Information retrieval systems employing an intelligent search agent that generates adaptive search strategies based on human search expertise could be helpful in meeting clinician information needs. A prerequisite for creating such systems is an information seeking model that facilitates the representation of human search expertise. The purpose of developing such a model is to provide guidance to information seeking system development and to shape an empirical research program. Design: The information seeking process was modeled as a complex problem-solving activity. After considering how similarly complex activities had been modeled in other domains, we determined that modeling context-initiated information seeking across multiple problem spaces allows the abstraction of search knowledge into functionally consistent layers. The knowledge layers were identified in the information science literature and validated through our observations of searches performed by health science librarians. Results: A hierarchical multi-level model of context-initiated information seeking is proposed. Each level represents (1) a problem space that is traversed during the online search process, and (2) a distinct layer of knowledge that is required to execute a successful search. Grand strategy determines what information resources will be searched, for what purpose, and in what order. The strategy level represents an overall approach for searching a single resource. Tactics are individual moves made to further a strategy. Operations are mappings of abstract intentions to information resource-specific concrete input. Assessment is the basis of interaction within the strategic hierarchy, influencing the direction of the search. Conclusion: The described multi-level model provides a framework for future research and the foundation for development of an automated information retrieval system that uses an intelligent search agent to bridge clinician information needs and human search expertise. PMID:18006383

Hung, Peter W.; Johnson, Stephen B.; Kaufman, David R.; Mendonça, Eneida A.

2008-01-01

230

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

231

Alternative algebras admitting derivations with invertible values and invertible derivations  

NASA Astrophysics Data System (ADS)

We prove an analogue of the Bergen-Herstein-Lanski theorem for alternative algebras: describe all alternative algebras that admit derivations with invertible values. We also prove an analogue of Moens' theorem for alternative algebras (a finite-dimensional alternative algebra over a field of characteristic zero is nilpotent if and only if it admits an invertible Leibniz derivation).

Kaygorodov, I. B.; Popov, Yu S.

2014-10-01

232

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

233

Invertible matrices over finite additively idempotent semirings  

E-print Network

We investigate invertible matrices over finite additively idempotent semirings. The main result provides a criterion for the invertibility of such matrices. We also give a construction of the inverse matrix and a formula for the number of invertible matrices.

Kendziorra, Andreas; Zumbrägel, Jens

2011-01-01

234

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

235

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

236

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

237

Coaxial inverted geometry transistor having buried emitter  

NASA Technical Reports Server (NTRS)

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

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

1973-01-01

238

IEEE TRANSACTIONS ON SYSTEM, MAN AND CYBERNETICS, PART B VOL. XX, NO. XX, XXXX 2012 1 Multi-Level Depth and Image Fusion for Human  

E-print Network

levels of the video processing pipeline. In the individual visual feature detection level, depth based-object and human-surroundings demonstrate the effectiveness of the proposed multi-level grayscale + depth fusionIEEE TRANSACTIONS ON SYSTEM, MAN AND CYBERNETICS, PART B VOL. XX, NO. XX, XXXX 2012 1 Multi-Level

Moulin, Pierre

239

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

NASA Astrophysics Data System (ADS)

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

Stanga, I. C.; Grozavu, A.

2012-04-01

240

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

241

An Alternative Construction of Internodons: The Emergence of a Multi-level Tree of Life.  

PubMed

Internodons are a formalization of Hennig's concept of species. We present an alternative construction of internodons imposing a tree structure on the genealogical network. We prove that the segments (trivial unary trees) from this tree structure are precisely the internodons. We obtain the following spin-offs. First, the generated tree turns out to be an organismal tree of life. Second, this organismal tree is homeomorphic to the phylogenetic Hennigian species tree of life, implying the discovery of a multi-level tree of life: this phylogenetic tree can be obtained by zooming out from the organismal tree, or conversely, the organismal tree of life can be generated by expanding the phylogenetic nodes into unary trees. Finally, the definition of the organismal tree allows an efficient algorithmic transformation of a given genealogical network into its corresponding phylogenetic species tree of life. The latter will be presented in a separate paper. PMID:25515028

Alexander, Samuel A; de Bruin, Arie; Kornet, D J

2015-01-01

242

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

243

Post-stroke balance rehabilitation under multi-level electrotherapy: a conceptual review  

PubMed Central

Stroke is caused when an artery carrying blood from heart to an area in the brain bursts or a clot obstructs the blood flow thereby preventing delivery of oxygen and nutrients. About half of the stroke survivors are left with some degree of disability. Innovative methodologies for restorative neurorehabilitation are urgently required to reduce long-term disability. The ability of the nervous system to respond to intrinsic or extrinsic stimuli by reorganizing its structure, function, and connections is called neuroplasticity. Neuroplasticity is involved in post-stroke functional disturbances, but also in rehabilitation. It has been shown that active cortical participation in a closed-loop brain machine interface (BMI) can induce neuroplasticity in cortical networks where the brain acts as a controller, e.g., during a visuomotor task. Here, the motor task can be assisted with neuromuscular electrical stimulation (NMES) where the BMI will act as a real-time decoder. However, the cortical control and induction of neuroplasticity in a closed-loop BMI is also dependent on the state of brain, e.g., visuospatial attention during visuomotor task performance. In fact, spatial neglect is a hidden disability that is a common complication of stroke and is associated with prolonged hospital stays, accidents, falls, safety problems, and chronic functional disability. This hypothesis and theory article presents a multi-level electrotherapy paradigm toward motor rehabilitation in virtual reality that postulates that while the brain acts as a controller in a closed-loop BMI to drive NMES, the state of brain can be can be altered toward improvement of visuomotor task performance with non-invasive brain stimulation (NIBS). This leads to a multi-level electrotherapy paradigm where a virtual reality-based adaptive response technology is proposed for post-stroke balance rehabilitation. In this article, we present a conceptual review of the related experimental findings. PMID:25565937

Dutta, Anirban; Lahiri, Uttama; Das, Abhijit; Nitsche, Michael A.; Guiraud, David

2014-01-01

244

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

245

Structured Multi-level Data Fusion and Modelling of Heterogeneous Environmental Data for Future Internet Applications  

NASA Astrophysics Data System (ADS)

The rapid increase in environmental observations which are conducted by Small to Medium Enterprise communities and volunteers using affordable in situ sensors at various scales, in addition to the more established observatories set up by environmental and space agencies using airborne and space-borne sensing technologies is generating serious amounts of BIG data at ever increasing speeds. Furthermore, the emergence of Future Internet technologies and the urgent requirements for the deployment of specific enablers for the delivery of processed environmental knowledge in real-time with advanced situation awareness to citizens has reached paramount importance. Specifically, it has become highly critical now to build and provide services which automate the aggregation of data from various sources, while surmounting the semantic gaps, conflicts and heterogeneity in data sources. The early stage aggregation of data will enable the pre-processing of data from multiple sources while reconciling the temporal gaps in measurement time series, and aligning their respective a-synchronicities. This low level type of data fusion process needs to be automated and chained to more advanced level of data fusion services specialising in observation forecasts at spaces where sensing is not deployed; or at time slices where sensing has not taken place yet. As a result, multi-level fusion services are required among the families of specific enablers for monitoring environments and spaces in the Future Internet. These have been intially deployed and piloted in the ongoing ENVIROFI project of the FI-PPP programme [1]. Automated fusion and modelling of in situ and remote sensing data has been set up and the experimentation successfully conducted using RBF networks for the spatial fusion of water quality parameters measurements from satellite and stationary buoys in the Irish Sea. The RBF networks method scales for the spatial data fusion of multiple types of observation sources. This important approach provides a strong basis for the delivery of environmental observations at desired spatial and temporal scales to multiple users with various needs of spatial and temporal resolutions. It has also led to building robust future internet specific enablers on data fusion, which can indeed be used for multiple usage areas above and beyond the environmental domains of the Future Internet. In this paper, data and processing workflow scenarios shall be described. The fucntionalities of the multi-level fusion services shall be demonstrated and made accessible to the wider communities of the Fututre Internet. [1] The Environmental Observation Web and its Service Applications within the Future Internet. ENVIROFI IP. FP7-2011-ICT-IF Pr.No: 284898 http://www.envirofi.eu/

Sabeur, Zoheir; Chakravarthy, Ajay; Bashevoy, Maxim; Modafferi, Stefano

2013-04-01

246

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

SciTech Connect

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

2014-01-13

247

Physical Activity Trajectories and Multi-Level Factors among Adolescent Girls  

PubMed Central

Purpose Although the decline of physical activity in adolescent girls is well-documented, there are girls whose physical activity does not follow this pattern. This study examined the relationships between physical activity trajectories and personal, psychosocial and environmental factors among adolescent girls. Methods Participants were from the University of Maryland field site of the Trial of Activity for Adolescent Girls. Of 730 girls measured in 8th grade, 589 were re-measured in 11th grade. Moderate to vigorous physical activity was assessed by accelererometers; participants were categorized as active maintainers (n=31), inactive maintainers (n=410), adopters (n=64), or relapsers (n=56). Height and weight were measured, personal and psychosocial information was collected from surveys, and distance from home to school and parks was assessed from Geographical Information Systems. Multivariable logistic regression was used for data analysis. Results Variables at individual, social, and environmental levels predicted active maintainers and inactive maintainers, while only individual-level variables predicted adoption. None predicted relapse. Higher (favorable) scores for physical self-concept, perceived body fat, friend and family physical activity support, frequency of physical activity with friends, and shorter distance from home to a park predicted active maintainers. Overweight/obese status, earlier age at menses, and lower scores for physical self-concept, perceived body fat, friend physical activity support, and frequency of physical activity with friends, and further distance from home to school predicted inactive maintainers. High physical self-concept and not being overweight/obese predicted adopters. Conclusion Multi-level factors appear to predict behavior maintenance rather than actual change. Implications and Contribution Although physical activity declines among girls during adolescence, some maintain and others increase their physical activity. Our results identified factors across individual, social, and environmental levels that predicted physical activity maintenance over 3 years. These may guide future interventions to enhance adolescent girls’ physical activity and combat the overall decline. PMID:23992761

Zook, Kathleen R.; Saksvig, Brit I.; Wu, Tong Tong

2013-01-01

248

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

249

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

NASA Astrophysics Data System (ADS)

Studying human behavior 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 1238 consecutive days, and analyze dynamical features of sequences of actions of players. We build on previous work where temporal structures of human actions of the same type were quantified, and 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 scales, bursty dynamics, and various functional forms on different time scales. We comment on gender differences of players in emotional actions, and find that while males and females act similarly when performing some positive actions, females are slightly faster for negative actions. We also observe effects on the age of players: more experienced players are generally faster in making decisions about engaging in and terminating enmity and friendship, respectively.

Mryglod, O.; Fuchs, B.; Szell, M.; Holovatch, Yu.; Thurner, S.

2015-02-01

250

Modeling fuzzy multi-period production planning and sourcing problem with credibility service levels  

NASA Astrophysics Data System (ADS)

A great deal of research has been done on production planning and sourcing problems, most of which concern deterministic or stochastic demand and cost situations and single period systems. In this paper, we consider a new class of multi-period production planning and sourcing problem with credibility service levels, in which a manufacturer has a number of plants and subcontractors and has to meet the product demand according to the credibility service levels set by its customers. In the proposed problem, demands and costs are uncertain and assumed to be fuzzy variables with known possibility distributions. The objective of the problem is to minimize the total expected cost, including the expected value of the sum of the inventory holding and production cost in the planning horizon. Because the proposed problem is too complex to apply conventional optimization algorithms, we suggest an approximation approach (AA) to evaluate the objective function. After that, two algorithms are designed to solve the proposed production planning problem. The first is a PSO algorithm combining the AA, and the second is a hybrid PSO algorithm integrating the AA, neural network (NN) and PSO. Finally, one numerical example is provided to compare the effectiveness of the proposed two algorithms.

Lan, Yan-Fei; Liu, Yan-Kui; Sun, Gao-Ji

2009-09-01

251

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. PMID:25237886

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

2014-01-01

252

General Analysis of Three-Phase Inverters  

Microsoft Academic Search

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

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

1969-01-01

253

Bi-level multi-source learning for heterogeneous block-wise missing data.  

PubMed

Bio-imaging technologies allow scientists to collect large amounts of high-dimensional data from multiple heterogeneous sources for many biomedical applications. In the study of Alzheimer's Disease (AD), neuroimaging data, gene/protein expression data, etc., are often analyzed together to improve predictive power. Joint learning from multiple complementary data sources is advantageous, but feature-pruning and data source selection are critical to learn interpretable models from high-dimensional data. Often, the data collected has block-wise missing entries. In the Alzheimer's Disease Neuroimaging Initiative (ADNI), most subjects have MRI and genetic information, but only half have cerebrospinal fluid (CSF) measures, a different half has FDG-PET; only some have proteomic data. Here we propose how to effectively integrate information from multiple heterogeneous data sources when data is block-wise missing. We present a unified "bi-level" learning model for complete multi-source data, and extend it to incomplete data. Our major contributions are: (1) our proposed models unify feature-level and source-level analysis, including several existing feature learning approaches as special cases; (2) the model for incomplete data avoids imputing missing data and offers superior performance; it generalizes to other applications with block-wise missing data sources; (3) we present efficient optimization algorithms for modeling complete and incomplete data. We comprehensively evaluate the proposed models including all ADNI subjects with at least one of four data types at baseline: MRI, FDG-PET, CSF and proteomics. Our proposed models compare favorably with existing approaches. PMID:23988272

Xiang, Shuo; Yuan, Lei; Fan, Wei; Wang, Yalin; Thompson, Paul M; Ye, Jieping

2014-11-15

254

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

SciTech Connect

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

Steill, Jeffrey D

2015-01-01

255

The geometry of ?-invertible sheaves  

NASA Astrophysics Data System (ADS)

Using the fact that ?-invertible sheaves can be interpreted as locally free sheaves of modules for the super skew field D, we give a new construction of the ?-projective superspace P?,Bn over affine k superschemes B, k an algebraically closed field. We characterize morphisms into P?,Bn and give a new interpretation of the composition of ?-invertible sheaves in terms of the algebra of D.

Kwok, Stephen

2014-12-01

256

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

257

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

258

Target recognition for the two color IR imaging system based on the multi-classifiers decision level fusion  

Microsoft Academic Search

Aim at the problem of Automatic Target Recognition (ATR) for the two color IR imaging system, presented a method for the IR dual band image target recognition based on multi- classifiers decision level fusion. This method firstly inputted all kinds of feature vectors of the target image into these relevant classifiers respectively to get the likelihood ratio of the target

Li Qiuhua; Lei Bin; Du Yi

2011-01-01

259

The three-level scaling approach with application to the Purdue University MultiDimensional Integral Test Assembly (PUMA)  

Microsoft Academic Search

The three-level scaling approach was developed for the scientific design of an integral test facility and then it was applied to the design of the scaled facility known as the Purdue University Multi-Dimensional Integral Test Assembly (PUMA). The NRC Technical Program Group for severe accident scaling developed the conceptual framework for this scaling methodology. The present scaling method consists of

M. Ishii; S. T. Revankar; T. Leonardi; R. Dowlati; M. L. Bertodano; I. Babelli; W. Wang; H. Pokharna; V. H. Ransom; R. Viskanta; J. T. Han

1998-01-01

260

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

261

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

262

Control of cascaded H-bridge inverters using an FPGA-based platform  

Microsoft Academic Search

Cascaded H-bridge multilevel inverters are highly modular converters particularly suitable for generating high output voltages and connecting independent dc sources like solar arrays or fuel cells. Three-phase multilevel inverters based on cascaded H-bridge inverters require a large number of control signals, particularly if the number of levels is high. In this case, Field-Programmable Gate Array appears as the right solution

Emanuel C. Meireles; Antonio P. Martins

2011-01-01

263

CMT: A Constrained Multi-Level Thresholding Approach for ChIP-Seq Data Analysis  

PubMed Central

Genome-wide profiling of DNA-binding proteins using ChIP-Seq has emerged as an alternative to ChIP-chip methods. ChIP-Seq technology offers many advantages over ChIP-chip arrays, including but not limited to less noise, higher resolution, and more coverage. Several algorithms have been developed to take advantage of these abilities and find enriched regions by analyzing ChIP-Seq data. However, the complexity of analyzing various patterns of ChIP-Seq signals still needs the development of new algorithms. Most current algorithms use various heuristics to detect regions accurately. However, despite how many formulations are available, it is still difficult to accurately determine individual peaks corresponding to each binding event. We developed Constrained Multi-level Thresholding (CMT), an algorithm used to detect enriched regions on ChIP-Seq data. CMT employs a constraint-based module that can target regions within a specific range. We show that CMT has higher accuracy in detecting enriched regions (peaks) by objectively assessing its performance relative to other previously proposed peak finders. This is shown by testing three algorithms on the well-known FoxA1 Data set, four transcription factors (with a total of six antibodies) for Drosophila melanogaster and the H3K4ac antibody dataset. PMID:24736605

Rezaeian, Iman; Rueda, Luis

2014-01-01

264

Aircraft Fault Detection and Classification Using Multi-Level Immune Learning Detection  

NASA Technical Reports Server (NTRS)

This work is an extension of a recently developed software tool called MILD (Multi-level Immune Learning Detection), which implements a negative selection algorithm for anomaly and fault detection that is inspired by the human immune system. The immunity-based approach can detect a broad spectrum of known and unforeseen faults. We extend MILD by applying a neural network classifier to identify the pattern of fault detectors that are activated during fault detection. Consequently, MILD now performs fault detection and identification of the system under investigation. This paper describes the application of MILD to detect and classify faults of a generic transport aircraft augmented with an intelligent flight controller. The intelligent control architecture is designed to accommodate faults without the need to explicitly identify them. Adding knowledge about the existence and type of a fault will improve the handling qualities of a degraded aircraft and impact tactical and strategic maneuvering decisions. In addition, providing fault information to the pilot is important for maintaining situational awareness so that he can avoid performing an action that might lead to unexpected behavior - e.g., an action that exceeds the remaining control authority of the damaged aircraft. We discuss the detection and classification results of simulated failures of the aircraft's control system and show that MILD is effective at determining the problem with low false alarm and misclassification rates.

Wong, Derek; Poll, Scott; KrishnaKumar, Kalmanje

2005-01-01

265

Hybrid PV/diesel solar power system design using multi-level factor analysis optimization  

NASA Astrophysics Data System (ADS)

Solar power systems represent a large area of interest across a spectrum of organizations at a global level. It was determined that a clear understanding of current state of the art software and design methods, as well as optimization methods, could be used to improve the design methodology. Solar power design literature was researched for an in depth understanding of solar power system design methods and algorithms. Multiple software packages for the design and optimization of solar power systems were analyzed for a critical understanding of their design workflow. In addition, several methods of optimization were studied, including brute force, Pareto analysis, Monte Carlo, linear and nonlinear programming, and multi-way factor analysis. Factor analysis was selected as the most efficient optimization method for engineering design as it applied to solar power system design. The solar power design algorithms, software work flow analysis, and factor analysis optimization were combined to develop a solar power system design optimization software package called FireDrake. This software was used for the design of multiple solar power systems in conjunction with an energy audit case study performed in seven Tibetan refugee camps located in Mainpat, India. A report of solar system designs for the camps, as well as a proposed schedule for future installations was generated. It was determined that there were several improvements that could be made to the state of the art in modern solar power system design, though the complexity of current applications is significant.

Drake, Joshua P.

266

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 Alzheimer’s 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

267

Costs and quality of hospitals in different health care systems: a multi-level approach with propensity score matching.  

PubMed

Cross-country comparisons of costs and quality between hospitals are often made at the macro level. The goal of this study was to explore methods to compare micro-level data from hospitals in different health care systems. To do so, we developed a multi-level framework in combination with a propensity score matching technique using similarly structured data for patients receiving treatment for acute myocardial infarction in German and US Veterans Health Administration hospitals. Our case study shows important differences in results between multi-level regressions based on matched and unmatched samples. We conclude that propensity score matching techniques are an appropriate way to deal with the usual baseline imbalances across the samples from different countries. Multi-level models are recommendable to consider the clustered structure of the data when patient-level data from different hospitals and health care systems are compared. The results provide an important justification for exploring new ways in performing health system comparisons. PMID:20084662

Schreyögg, Jonas; Stargardt, Tom; Tiemann, Oliver

2011-01-01

268

Planar wire array performance scaling at multi-MA levels on the Saturn generator.  

SciTech Connect

A series of twelve shots were performed on the Saturn generator in order to conduct an initial evaluation of the planar wire array z-pinch concept at multi-MA current levels. Planar wire arrays, in which all wires lie in a single plane, could offer advantages over standard cylindrical wire arrays for driving hohlraums for inertial confinement fusion studies as the surface area of the electrodes in the load region (which serve as hohlraum walls) may be substantially reduced. In these experiments, mass and array width scans were performed using tungsten wires. A maximum total radiated x-ray power of 10 {+-} 2 TW was observed with 20 mm wide arrays imploding in {approx}100 ns at a load current of {approx}3 MA, limited by the high inductance. Decreased power in the 4-6 TW range was observed at the smallest width studied (8 mm). 10 kJ of Al K-shell x-rays were obtained in one Al planar array fielded. This report will discuss the zero-dimensional calculations used to design the loads, the results of the experiments, and potential future research to determine if planar wire arrays will continue to scale favorably at current levels typical of the Z machine. Implosion dynamics will be discussed, including x-ray self-emission imaging used to infer the velocity of the implosion front and the potential role of trailing mass. Resistive heating has been previously cited as the cause for enhanced yields observed in excess of jxB-coupled energy. The analysis presented in this report suggests that jxB-coupled energy may explain as much as the energy in the first x-ray pulse but not the total yield, which is similar to our present understanding of cylindrical wire array behavior.

Chuvatin, Alexander S. (Laboratoire du Centre National de la Recherche Scientifique Ecole Polytechnique, Palaiseau, France); Jones, Michael; Vesey, Roger Alan; Waisman, Eduardo M.; Esaulov, Andrey A. (University of Nevada, Reno, NV); Ampleford, David J.; Kantsyrev, Victor Leonidovich (University of Nevada, Reno, NV); Cuneo, Michael Edward; Rudakov, L. I. (Icarus Research Inc., Bethesda, MD); Coverdale, Christine Anne; Jones, Brent Manley; Safronova, Alla S. (University of Nevada, Reno, NV)

2007-10-01

269

PWR integrated safety analysis methodology using multi-level coupling algorithm  

NASA Astrophysics Data System (ADS)

Coupled three-dimensional (3D) neutronics/thermal-hydraulic (T-H) system codes give a unique opportunity for a realistic modeling of the plant transients and design basis accidents (DBA) occurring in light water reactors (LWR). Examples of such DBAs are the rod ejection accidents (REA) and the main steam line break (MSLB) that constitute the bounding safety problems for pressurized water reactors (PWR). These accidents involve asymmetric 3D spatial neutronic and T-H effects during the course of the transients. The thermal margins (the peak fuel temperature, and departure from nucleate boiling ratio (DNBR)) are the measures of safety at a particular transient and need to be evaluated as accurate as possible. Modern 3D neutronics/T-H coupled codes estimate the safety margins coarsely on an assembly level, i.e. for an average fuel pin. More accurate prediction of the safety margins requires the evaluation of the transient fuel rod response involving locally coupled neutronics/T-H calculations. The proposed approach is to perform an on-line hot-channel safety analysis not for the whole core but for a selected local region, for example for the highest power loaded fuel assembly. This approach becomes feasible if an on-line algorithm capable to extract the necessary input data for a sub-channel module is available. The necessary input data include the detailed pin-power distributions and the T-H boundary conditions for each sub-channel in the considered problem. Therefore, two potential challenges are faced in the development of refined methodology for evaluation of local safety parameters. One is the development of an efficient transient pin-power reconstruction algorithm with a consistent cross-section modeling. The second is the development of a multi-level coupling algorithm for the T-H boundary and feed-back data exchange between the sub-channel module and the main 3D neutron kinetics/T-H system code, which already uses one level of coupling scheme between 3D neutronics and core thermal-hydraulics models. The major accomplishment of the thesis is the development of an integrated PWR safety analysis methodology with locally refined safety evaluations. This involved introduction of an improved method capable of efficiently restoring the fine pin-power distribution with a high degree of accuracy. In order to apply the methodology to evaluate the safety margins on a pin level, a refined on-line hot channel model was developed accounting for the cross-flow effects. Finally, this methodology was applied to best estimate safety analysis to more accurately calculate the thermal safety margins occurring during a design basis accident in PWR.

Ziabletsev, Dmitri Nickolaevich

270

Intravital multi-photon microscopy reveals several levels of heterogeneity in endocytic uptake by mouse renal proximal tubules.  

PubMed

Understanding renal function requires one to integrate the structural complexity of kidney nephrons and the dynamic nature of their cellular processes. Multi-photon fluorescence microscopy is a state-of-the-art imaging technique for in vivo analysis of kidney tubules structure and function in real time. This study presents visual evidence for several levels of heterogeneity of proximal tubular endocytic uptake in the superficial renal mouse cortex and illustrates the potential of multi-photon microscopy for providing a comprehensive and dynamic portrayal of renal function. PMID:18081693

Caplanusi, A; Parreira, K S; Lima, W Rezende; Marien, B; Van Der Smissen, P; de Diesbach, P; Devuyst, O; Courtoy, P J

2008-01-01

271

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

272

Using the level set method in geodynamical modeling of multi-material flows and Earth's free surface  

NASA Astrophysics Data System (ADS)

The level set method allows for tracking material surfaces in 2-D and 3-D flow modeling and is well suited for applications of multi-material flow modeling. The level set method utilizes smooth level set functions to define material interfaces, which makes the method stable and free of oscillations that are typically observed in case step-like functions parameterize interfaces. By design the level set function is a signed distance function and gives for each point in the domain the exact distance to the interface as well as on which side it is located. In this paper we present four benchmarks which show the validity, accuracy and simplicity of using the level set method for multi-material flow modeling. The benchmarks are simplified setups of dynamical geophysical processes such as the Rayleigh-Taylor instability, post-glacial rebound, subduction and slab detachment. We also demonstrate the benefit of using the level set method for modeling a free surface with the sticky air approach. Our results show that the level set method allows for accurate material flow modeling and that the combination with the sticky air approach works well in mimicking Earth's free surface. Since the level set method tracks material interfaces instead of materials themselves, it has the advantage that the location of these interfaces is accurately known and that it represents a viable alternative to the more commonly used tracer method.

Hillebrand, B.; Thieulot, C.; Geenen, T.; van den Berg, A. P.; Spakman, W.

2014-11-01

273

Inverter design for high frequency power distribution  

NASA Technical Reports Server (NTRS)

A class of simple resonantly commutated inverters are investigated for use in a high power (100 KW - 1000 KW) high frequency (10 KHz - 20 KHz) AC power distribution system. The Mapham inverter is found to provide a unique combination of large thyristor turn-off angle and good utilization factor, much better than an alternate 'current-fed' inverter. The effects of loading the Mapham inverter entirely with rectifier loads are investigated by simulation and with an experimental 3 KW 20 KHz inverter. This inverter is found to be well suited to a power system with heavy rectifier loading.

King, R. J.

1985-01-01

274

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

275

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

276

A dedicated database system for handling multi-level data in systems biology  

PubMed Central

Background Advances in high-throughput technologies have enabled extensive generation of multi-level omics data. These data are crucial for systems biology research, though they are complex, heterogeneous, highly dynamic, incomplete and distributed among public databases. This leads to difficulties in data accessibility and often results in errors when data are merged and integrated from varied resources. Therefore, integration and management of systems biological data remain very challenging. Methods To overcome this, we designed and developed a dedicated database system that can serve and solve the vital issues in data management and hereby facilitate data integration, modeling and analysis in systems biology within a sole database. In addition, a yeast data repository was implemented as an integrated database environment which is operated by the database system. Two applications were implemented to demonstrate extensibility and utilization of the system. Both illustrate how the user can access the database via the web query function and implemented scripts. These scripts are specific for two sample cases: 1) Detecting the pheromone pathway in protein interaction networks; and 2) Finding metabolic reactions regulated by Snf1 kinase. Results and conclusion In this study we present the design of database system which offers an extensible environment to efficiently capture the majority of biological entities and relations encountered in systems biology. Critical functions and control processes were designed and implemented to ensure consistent, efficient, secure and reliable transactions. The two sample cases on the yeast integrated data clearly demonstrate the value of a sole database environment for systems biology research. PMID:25053973

2014-01-01

277

GAMA: a spatially explicit, multi-level, agent-based modeling and simulation platform  

E-print Network

manuscript, published in "Practical Applications of Agents and Multi-Agent Systems, Spain (2013)" #12;2 agent brought a new way to study complex sys- tems by allowing to represent multiple heterogeneous entities

Paris-Sud XI, Université de

278

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

NASA Astrophysics Data System (ADS)

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 parameters and catchment characteristics. Recently few studies are presented on lake level simulation of Lake Tana. In these studies the water balance of the lake is closed by estimation of runoff contributions from ungauged catchments. Studies partly relied on simple ad-hoc procedures of area comparison to estimate runoff from ungauged catchments. In this study a regional model is developed that relies on principles of similarity of catchments. For runoff modelling the HVB-96 model is selected while multi-objective model calibration is by a Monte Carlo procedure. Assessment of the lake water balance was established by comparing measured to estimated lake levels. Results of daily lake level simulation show a water balance closure term of 85 mm and a relative volume error of 2.17%. Results show runoff from ungauged catchments of 527 mm per year for the simulation period 1994 to 2003 that is approximately 30% of Lake Tana stream flow inflow. Compared to previous works this closure term is smallest.

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

2010-09-01

279

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

280

A distributed TS-MUX architecture for multi-chip extension beyond the HDTV level  

Microsoft Academic Search

This paper proposes a distributed stream multiplexing architecture for CODEC LSIs with multi-chip configuration, and demonstrates its scalability and usefulness. It consists of each media multiplexing unit with an external stream input and inter-chip communication interfaces. Parallel protocol processing, with an autonomous inter-chip control mechanism to mix and concatenate packets through daisy-chained transfer paths, provides a complete multi-chip output at

Takayuki Onishi; Mitsuo Ikeda; Jiro Naganuma; Makoto Endo; Yoshiyuki Yashima

2004-01-01

281

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 youth’s neighborhood environments altering family characteristics and youth psychosocial and behavioral profiles, thereby increasing youth’s risk for health problems. We also note the importance of acknowledging reciprocal influences across levels and domains (e.g., between family and child) that create self-perpetuating patterns of influence that further accentuate the impact of these factors on youth health. Finally, we document that factors across levels can interact (e.g., environmental pollution levels with child stress) to create unique, synergistic effects on youth health. Our model stresses the importance of evaluating influences on youth’s physical health not in isolation but in the context of the broader social and physical environments in which youth live. Understanding the complex relationships between the factors that link low SES to youth’s long-term health trajectories is necessary for the creation and implementation of successful interventions and policies to ultimately reduce health disparities. PMID:22845752

Schreier, Hannah M. C.; Chen, Edith

2012-01-01

282

PWM Inverter Output Filter Cost to Losses Trade Off and Optimal Design  

E-print Network

--This paper describes how to design the output filter of a PWM inverter used in a Uninterruptible Power SupplyVA 3-ph. PWM inverter is taken as example. B. Design Constraints Uninterruptible Power Supply (UPS-losses trade-off curves are deduced. Two power levels (30kVA and 300kVA) are taken as design example

Paris-Sud XI, Université de

283

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

284

Photovoltaic AC module composed of a very large number of interleaved inverters  

Microsoft Academic Search

A photovoltaic panel fitted with a large collection of low-power inverters integrated at the level of individual solar cells is used to design an ac module. To facilitate dc-ac power conversion, the inverter aggregate is controlled using interleaved carrier pulse width modulation. Every solar cell operates at its maximum power point even when the photovoltaic panel is partially shaded. Additionally,

Brian Johnson; Philip Krein; Patrick Chapman

2011-01-01

285

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

286

Complex carbon cycle responses to multi-level warming and supplemental summer rain in the high Arctic.  

PubMed

The Arctic has experienced rapid warming and, although there are uncertainties, increases in precipitation are projected to accompany future warming. Climate changes are expected to affect magnitudes of gross ecosystem photosynthesis (GEP), ecosystem respiration (ER) and the net ecosystem exchange of CO2 (NEE). Furthermore, ecosystem responses to climate change are likely to be characterized by nonlinearities, thresholds and interactions among system components and the driving variables. These complex interactions increase the difficulty of predicting responses to climate change and necessitate the use of manipulative experiments. In 2003, we established a long-term, multi-level and multi-factor climate change experiment in a polar semidesert in northwest Greenland. Two levels of heating (30 and 60 W m(-2) ) were applied and the higher level was combined with supplemental summer rain. We made plot-level measurements of CO2 exchange, plant community composition, foliar nitrogen concentrations, leaf ?(13) C and NDVI to examine responses to our treatments at ecosystem- and leaf-levels. We confronted simple models of GEP and ER with our data to test hypotheses regarding key drivers of CO2 exchange and to estimate growing season CO2 -C budgets. Low-level warming increased the magnitude of the ecosystem C sink. Meanwhile, high-level warming made the ecosystem a source of C to the atmosphere. When high-level warming was combined with increased summer rain, the ecosystem became a C sink of magnitude similar to that observed under low-level warming. Competition among our ER models revealed the importance of soil moisture as a driving variable, likely through its effects on microbial activity and nutrient cycling. Measurements of community composition and proxies for leaf-level physiology suggest GEP responses largely reflect changes in leaf area of Salix arctica, rather than changes in leaf-level physiology. Our findings indicate that the sign and magnitude of the future High Arctic C budget may depend upon changes in summer rain. PMID:23504924

Sharp, Elizabeth D; Sullivan, Patrick F; Steltzer, Heidi; Csank, Adam Z; Welker, Jeffrey M

2013-06-01

287

Integration Technology of 30nm Generation MultiLevel NAND Flash for 64Gb NAND Flash Memory  

Microsoft Academic Search

Multi-level NAND flash memories with a 38 nm design rule have been successfully developed for the first time. A breakthrough patterning technology of Self Aligned Double Patterning (SADP) together with ArF lithography is applied to three critical lithographic steps. Other key integration technologies include low thermal budget ILD process and twisted bit-line contact for excellent isolation between adjacent bit lines.

Donghwa Kwak; Keonsoo Kim; Yongsik Yim; Soojin Ahn; Jinho Kim; Woncheol Jeong; Jooyoung Kim; Byungkwan Yoo; Sangbin Song; Hyunsuk Kim; Jaehwang Sim; Sunghyun Kwon; Byungjoon Hwang; Hyung-kyu Park; Sunghoon Kim; Yunkyoung Lee; Hwagyung Shin; Namsoo Yim; Kwangseok Lee; Minjung Kim; Youngho Lee; Sangyong Park; Jaesuk Jung; Kinam Kim

2007-01-01

288

Feature-Level Fusion by Multi-Objective Binary Particle Swarm Based Unbiased Feature Selection for Optimized Sensor System Design  

Microsoft Academic Search

The performance of recognition systems in intelligent sensor technology can often be improved by using the combined information of several different measurement results, i.e., signal processing and feature computation, of single-sensor and\\/or multi-sensor information. However, the large dimensional data caused by feature-level fusion imposes an accuracy problem on classification tasks, due to some irrelevant and\\/or redundant features. For this reason,

Kuncup Iswandy; Andreas Koenig

2006-01-01

289

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

290

Enabling the MLSpOC (Multi-Level Space Operations Center) of the Future  

NASA Astrophysics Data System (ADS)

The Intelligence Reform and Terrorism Prevention Act, passed by Congress in 2004, established the expectation that the "vast intelligence enterprise" of the United States would become more unified, coordinated, and effective. This law charged the intelligence community and government agencies to integrate foreign intelligence and domestic US intelligence components to reduce gaps in understanding threats to our national security and to improve our reaction. This intelligence strategy — designed to provide more comprehensive and accurate intelligence analysis—substantially increases requirements for secure data sharing capabilities. An information system must be Certified & Accredited (C&A) by the appropriate Accreditation Authority in accordance with each Authority's prescribed compliance requirements and governance. Cross-Domain Solutions (CDSs) can provide the ability to share data between multiple operating domains (e.g. among users on Top Secret and Secret networks). However, sharing sensitive data across security domains and networks has been impeded by both technical and cultural challenges. A viable CDS requires a tremendous investment for initial C&A and many solutions are limited with respect to the integration of an organization's applications. As a result, most of today's highly secured systems have been designed to restrict access to entire user populations rather than implement data sharing on the basis of mandatory access controls and an individual's need-to-know. Most CDSs today are based on one-way replication through data transfer guards that copy data from one network to another. This model inherently builds in additional and extensive Operations and Maintenance (O&M) costs. Oracle's National Security Group challenged its top engineers and security architects to engineer the first Cross-Domain database providing a practical and robust solution to the Cross-Domain security problem. The result is the MLSpOC, which is deployed, fielded, and accredited today at multiple sites both CONUS and OCONUS. It is designed to assist information systems developers achieve DCID 6/3 Protection Level 4 or 5 (PL4 or PL5) or DoD SABI C&A for SECRET-to-UNCLASSIFIED systems (PL3). The product is on the DoD/DNI Unified Cross-domain Management Office's (UCDMO) Baseline of accredited solutions, and is the only solution on the Baseline which the Government considers to be an "All-in-One" approach to the Cross-domain Security challenge. Our solution is also the only PL-4 Cloud in existence and that is deployed and operational in the entire world today (at DIA). The Space marketplace is a very unique cross-domain challenge, as a need exists for Unclassified SSA Data Sharing at a deeper and more fundamental level than anywhere else in the IC or DoD. For instance, certain Agencies and/or Programs have a requirement to share information with Partner Nations that are not considered to be "friendly" (e.g. China). Our Solution is the ONLY solution in the world today that's achieved C&A, and that is uniquely positioned to enable the Multi-level Space Operations Center (MLSpOC) of the Future.

Missal, D.

2012-09-01

291

Inverters for Uninterruptible Power Supplies  

Microsoft Academic Search

The synthesis of the principal types of inverters that are best suited for static uninterruptible power supplies (UPS) is sought. From this synthesis a range of apparatus is evolved that will satisfy present and future needs. For each point of this range new solutions are indicated; their development is tied with the technological evolution of the components. The reliability and

Robert Chauprade

1977-01-01

292

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

293

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

294

Security of Invertible Media Authentication Schemes Revisited  

Microsoft Academic Search

Dittmann, Katzenbeisser, Schallhart and Veith (IACR ePrint 2004) intro- duced the notion of invertible media authentication schemes, embedding authentication data in media objects via invertible watermarks. These invertible watermarks allow to recover the original media object (given a secret encryption key), as required for example in some medical applications where the distortion must be removable. Here we revisit the approach

Daniel Dönigus; Stefan Endler; Marc Fischlin; Andreas Hülsing; Patrick Jäger; Anja Lehmann; Sergey Podrazhansky; Sebastian Schipp; Erik Tews; Sven Vowe; Matthias Walthart; Frederik Weidemann

2007-01-01

295

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

296

Hybrid Multilevel Inverter with Single DC Haiwen Liu1  

E-print Network

multilevel inverter includes a standard 3-leg inverter (one leg for reach phase) and H-bridge in series inverter (one leg for each phase) and H-bridge in series with each inverter leg. The inverter can be used of the present DC-DC boost converter. To develop the model of hybrid multilevel inverter, a simulation is done

Tolbert, Leon M.

297

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

298

A multi-level system quality improvement intervention to reduce racial disparities in hypertension care and control: study protocol  

PubMed Central

Background Racial disparities in blood pressure control have been well documented in the United States. Research suggests that many factors contribute to this disparity, including barriers to care at patient, clinician, healthcare system, and community levels. To date, few interventions aimed at reducing hypertension disparities have addressed factors at all of these levels. This paper describes the design of Project ReD CHiP (Reducing Disparities and Controlling Hypertension in Primary Care), a multi-level system quality improvement project. By intervening on multiple levels, this project aims to reduce disparities in blood pressure control and improve guideline concordant hypertension care. Methods Using a pragmatic trial design, we are implementing three complementary multi-level interventions designed to improve blood pressure measurement, provide patient care management services and offer expanded provider education resources in six primary care clinics in Baltimore, Maryland. We are staggering the introduction of the interventions and will use Statistical Process Control (SPC) charting to determine if there are changes in outcomes at each clinic after implementation of each intervention. The main hypothesis is that each intervention will have an additive effect on improvements in guideline concordant care and reductions in hypertension disparities, but the combination of all three interventions will result in the greatest impact, followed by blood pressure measurement with care management support, blood pressure measurement with provider education, and blood pressure measurement only. This study also examines how organizational functioning and cultural competence affect the success of the interventions. Discussion As a quality improvement project, Project ReD CHiP employs a novel study design that specifically targets multi-level factors known to contribute to hypertension disparities. To facilitate its implementation and improve its sustainability, we have incorporated stakeholder input and tailored components of the interventions to meet the specific needs of the involved clinics and communities. Results from this study will provide knowledge about how integrated multi-level interventions can improve hypertension care and reduce disparities. Trial Registration ClinicalTrials.gov NCT01566864 PMID:23734703

2013-01-01

299

A High-Level Petri Net Framework for Multi-Valued Genetic Regulatory Networks  

Microsoft Academic Search

To understand the function of genetic regulatory networks in the development of cellular systems, we must not only realise the individual network entities, but also the manner by which they interact. Multi-valued networks are a promising qualitative approach for modelling such genetic regulatory networks, providing an interesting compromise between the simplicity of Boolean models and more detailed quantitative models. However,

Richard Banks; L. Jason Steggles

2007-01-01

300

Multi-level Exemplar Theory Michael Walsh, Bernd Mobius, Travis Wade, Hinrich Schutze  

E-print Network

exists between the submodel at the level of constituents and the submodel at the level of units and that the unit level submodel "wins" if the unit exemplar receives sufficient activation. Although a similar

Möbius, Bernd

301

Thermal Study of Inverter Components: Preprint  

SciTech Connect

Thermal histories of inverter components were collected from operating inverters from several manufacturers and three locations. The data were analyzed to determine thermal profiles, the dependence on local conditions, and to assess the effect on inverter reliability. Inverter temperatures were shown to increase with the power dissipation of the inverters, follow diurnal and annual cycles, and have a dependence on wind speed. An accumulated damage model was applied to the temperature profiles and an example of using these data to predict reliability was explored.

Sorensen, N. R.; Thomas, E. V.; Quintana, M. A.; Barkaszi, S.; Rosenthal, A.; Zhang, Z.; Kurtz, S.

2012-06-01

302

Complementary-like semiconducting graphene logic inverters  

NASA Astrophysics Data System (ADS)

The application of graphene as a post-silicon channel material is an interesting but challenging topic due to its metallic nature and low switching ratio. It is expected that the condition would change if a sizeable band gap is introduced. Here we report the electrical characteristics of the first semiconducting graphene-based logic inverters. Free of doping, the p- and n- branches in the bipolar graphene transistors are delicately used as the complementary components required in logic devices. Within perpendicular electric fields, large transport band gap (>100,eV) and high switching ratio (˜200 at 77,) are obtained in bilayer graphene channels. Besides, a simple and high capacitive-efficiency top gate with natural alumina dielectric (˜0.9,?F/cm^2) is adopted and the operating bias is lowered within 2,. For the first time, >1 voltage gain are extracted from graphene inverters. Voltage gain up to 8 and 2 are achieved at liquid-nitrogen and room temperatures, respectively. Importantly, a match between input and output voltage levels is realized, indicating the potential for direct cascading between multiple devices for future large-scale integration.

Li, Song-Lin; Miyazaki, Hisao; Tsukagoshi, Kazuhito; Kanda, Akinobu

2011-03-01

303

Performance Comparison Between Lqr and Pid Controllers for AN Inverted Pendulum System  

NASA Astrophysics Data System (ADS)

The objective of this paper is to compare the time specification performance between two conventional controllers for an inverted pendulum system. The goal is to determine which control strategy delivers better performance with respect to pendulum's angle and cart's position. The inverted pendulum represents a challenging control problem, which continually moves toward an uncontrolled state. Two controllers are presented such as Linear-Quadratic-Regulator (LQR) and Proportional-Integral-Derivatives (PID) controllers for controlling the linearized system of inverted pendulum model. Simulation study has been done in Matlab simulink environment shows that both controllers are capable to control multi output inverted pendulum system successfully. The result shows that LQR produced better response compared to PID control strategies and is presented in time domain.

Nasir, A. N. K.; Ahmad, M. A.; Rahmat, M. F.

2008-10-01

304

Inverted high-temperature quartz  

Microsoft Academic Search

Fifty-two samples of inverted high-temperature quartz from volcanic rocks were investigated by Guinier-Jago powder diffractometry\\u000a and differential scanning calorimetry (DSC). Quartz megacrysts from Clear Lake and Cinder Cone, California show a variability\\u000a of ?2.5 ° K in their ?-? transition temperature (T\\u000a ?-?). Quartz phenocrysts and quartz from crystalline rocks give a range of 0.5 ° K in T\\u000a ?-?.

M. S. Ghiorso; I. S. E. Carmichael; L. K. Moret

1979-01-01

305

The Inverted Snow Globe Shadow  

NASA Astrophysics Data System (ADS)

Our high school optics course finishes with an assignment that students usually appreciate. They must take pictures of everyday situations representing optical phenomena such as reflection, refraction, or dispersion, and post them on Instagram.1 When the photos were presented to the class, one student revealed an intriguing photo, similar to Fig. 1, showing a snow globe exposed to sunlight and its inverted shadow. This paper offers an explanation of the problem, which occurs due to light refraction from the globe.

Ribeiro, Jair Lúcio Prados

2015-01-01

306

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

307

Influence of the deuteration level of the KD*P crystal on multi-PW class OPCPA laser  

NASA Astrophysics Data System (ADS)

The deuteration level of the KD*P crystal plays a key role in the performance of large aperture OPCPA amplification stages. Whilst purely deuterated crystals show broadband amplification around 910 nm, the availability and optical quality of that type of crystal limit its use. A lower deuteration level has an impact on the phase matching and will increase the absorption in the IR region, reducing the bandwidth and the efficiency. However, these crystals have better optical quality and are easier to grow. In this paper we present a numerical study of OPCPA amplification for different deuteration levels, looking in particular at the small signal gain bandwidth and absorption. This study is important for the design and the realization of multi-PW laser systems based on OPCPA techniques.

Galimberti, Marco; Hernandez-Gomez, Cristina; Musgrave, Ian; Ross, Ian; Winstone, Trevor

2013-11-01

308

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

309

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

310

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.

311

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

312

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

PubMed

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. PMID:25149773

Mai, Sebastian; Müller, Thomas; Plasser, Felix; Marquetand, Philipp; Lischka, Hans; González, Leticia

2014-08-21

313

Identification of condition-specific regulatory modules through multi-level motif and mRNA expression analysis  

PubMed Central

Many computational methods for identification of transcription regulatory modules often result in many false positives in practice due to noise sources of binding information and gene expression profiling data. In this paper, we propose a multi-level strategy for condition-specific gene regulatory module identification by integrating motif binding information and gene expression data through support vector regression and significant analysis. We have demonstrated the feasibility of the proposed method on a yeast cell cycle data set. The study on a breast cancer microarray data set shows that it can successfully identify the significant and reliable regulatory modules associated with breast cancer. PMID:20054984

Chen, Li; Wang, Yue; Hoffman, Eric P.; Riggins, Rebecca B.; Clarke, Robert

2013-01-01

314

GAD: A 12GS\\/s CMOS 4-bit A\\/D converter for an equalized multi-level link  

Microsoft Academic Search

A 4-bit 12-GSample\\/sec A\\/D converter (GAD) has been fabricated in a 0.25-?m CMOS process to investigate the design of an equalized multi-level link. Clocked differential amplifiers were used to sample the input, followed by high-speed comparators with current-summed offset cancellation. Input bandwidth was measured at 2.5 GHz. Eight 1.5-GSample\\/sec flash A\\/D converters were interleaved to achieve the aggregate sample rate

William Ellersick; Chih-Kong Ken Yang; Mark Horowitz; William Dally

1999-01-01

315

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

316

Adapted from Chappell et al., [1999]. For an exception, see Turner & Turner, [1998], which describes a high level multi-agent  

E-print Network

describes a high level multi-agent simulator called CoDA. 1 An Environment for High-Level Multiple AUV with the higher level interactions among multiple heterogeneous participants; be those participants real VIPs heterogeneity pushes us to use the broader term agents in describing CADCON participants. 2 endeavored

317

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

318

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

319

Neighborhood Social Cohesion and Disorder in Relation to Walking in Community-Dwelling Older Adults: A Multi-Level Analysis  

PubMed Central

Objectives To examine the role of neighborhood social conditions and walking in community-dwelling older adults. Methods A multi-level analysis of data from 4,317 older adults (mean age = 74.5; 73% black) from a geographically-defined urban community. Participants completed structured interviews including 14 questions on neighborhood conditions and self-reported walking. The neighborhood questions were summarized into individual-level measures of perceived neighborhood social cohesion and disorder. These measures were aggregated by neighborhood to construct neighborhood-level measures of social cohesion and disorder. Results Neighborhood-level disorder, but not social cohesion, was significantly associated with walking, independent individual-level neighborhood perceptions and other correlates of walking. Further adjustment for race weakened this association to a marginally significant level. Discussion Neighborhood conditions may shape walking behavior in older adults, especially conditions that reflect physical neglect or social threat. Promotion of walking behavior in older adults may require improvement of the safety and upkeep of the neighborhood environment. PMID:19144973

Mendes de Leon, Carlos F.; Cagney, Kathleen A.; Bienias, Julia L.; Barnes, Lisa L.; Skarupski, Kimberly A.; Scherr, Paul A.; Evans, Danis A.

2008-01-01

320

Species composition of a soil invertebrate multi-species test system determines the level of ecotoxicity.  

PubMed

A soil multi-species, SMS, experimental test system consisting of the natural microbial community, five collembolan species and a predatory mite along with either Enchytraeus crypticus or the earthworm Eisenia fetida were exposed to ?-cypermethrin. A comparison of the performance of these two types of SMSs is given to aid the development of a standard test system. E. fetida had a positive effect on the majority of the species, reducing the negative insecticide effect. E. fetida affected the species sensitivity and decreased the degradation of the insecticide due to the organic matter incorporation of earthworm food. After 8 weeks, the EC50 was 0.76 mg kg(-1) for enchytraeids and ranged between 2.7 and 18.9 mg kg(-1) for collembolans, more sensitive than previously observed with single species. Changes observed in the community structure and function illustrates the strength of a multi-species test system as an ecotoxicological tool compared to single species tests. PMID:24201037

Sechi, Valentina; D'Annibale, Alessandra; Maraldo, Kristine; Johansen, Anders; Bossi, Rossana; Jensen, John; Krogh, Paul Henning

2014-01-01

321

Opal: A MultiLevel Infrastructure for Agent-Oriented Software Development  

Microsoft Academic Search

The Opal architecture for software development is described that supports the use of agent-oriented concepts at multiple levels of abstraction. At the lowest level are micro-agents, streamlined agents that can be used for conventional, system-level programming tasks. More sophisticated agents may be constructed by assembling combinations of micro-agents. The architecture consequently supports the systematic use of agent-based notions throughout the

M. Purvis; S. Cranefield; M. Nowostawski; D. Carter

2002-01-01

322

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

323

System and method for regulating resonant inverters  

DOEpatents

A technique is provided for direct digital phase control of resonant inverters based on sensing of one or more parameters of the resonant inverter. The resonant inverter control system includes a switching circuit for applying power signals to the resonant inverter and a sensor for sensing one or more parameters of the resonant inverter. The one or more parameters are representative of a phase angle. The resonant inverter control system also includes a comparator for comparing the one or more parameters to a reference value and a digital controller for determining timing of the one or more parameters and for regulating operation of the switching circuit based upon the timing of the one or more parameters.

Stevanovic, Ljubisa Dragoljub (Clifton Park, NY); Zane, Regan Andrew (Superior, CO)

2007-08-28

324

New type of transformerless high efficiency inverter  

NASA Astrophysics Data System (ADS)

Inverter architectures are presented which allow economical ac/dc switching for solar cell array and battery power use in domestic and industrial applications. The efficiencies of currently available inverters are examined and compared with a new 2.2 kW transformerless stepped wave inverter. The inverter has low no-load losses, amounting to 200 Wh/24 hr, and features voltage steps occurring 15-30 times/sine wave period. An example is provided for an array/battery/inverter assembly with the inverter control electronics activating or disconnecting the battery subassemblies based on the total number of activated subassemblies in relation to a reference sinewave, and the need to average the battery subassembly discharge rates. A total harmonic distortion of 6 percent was observed, and the system is noted to be usable as a battery charger.

Naaijer, G. J.

325

Multi-level slug tests in highly permeable formations: 2. Hydraulic conductivity identification, method verification, and field applications  

NASA Astrophysics Data System (ADS)

Using the developed theory and modified Springer-Gelhar (SG) model, an identification method is proposed for estimating hydraulic conductivity from multi-level slug tests. The computerized algorithm calculates hydraulic conductivity from both monotonic and oscillatory well responses obtained using a double-packer system. Field verification of the method was performed at a specially designed fully penetrating well of 0.1-m diameter with a 10-m screen in a sand and gravel alluvial aquifer (MSEA site, Shelton, Nebraska). During well installation, disturbed core samples were collected every 0.6 m using a split-spoon sampler. Vertical profiles of hydraulic conductivity were produced on the basis of grain-size analysis of the disturbed core samples. These results closely correlate with the vertical profile of horizontal hydraulic conductivity obtained by interpreting multi-level slug test responses using the modified SG model. The identification method was applied to interpret the response from 474 slug tests in 156 locations at the MSEA site. More than 60% of responses were oscillatory. The method produced a good match to experimental data for both oscillatory and monotonic responses using an automated curve matching procedure. The proposed method allowed us to drastically increase the efficiency of each well used for aquifer characterization and to process massive arrays of field data. Recommendations generalizing this experience to massive application of the proposed method are developed.

Zlotnlk, Vitaly A.; McGuire, Virginia L.

1998-01-01

326

A new non-overlapping concept to improve the Hybrid Particle Level Set method in multi-phase fluid flows  

NASA Astrophysics Data System (ADS)

A novel non-overlapping concept is augmented to the Hybrid Particle Level Set (HPLS) method to improve its accuracy and suitability for the modelling of multi-phase fluid flows. The concept addresses shortcomings in the reseeding algorithm, which maintains resolution of the surface at runtime. These shortcomings result in the misplacement of newly seeded particles in the opposite signed domain and necessitate a restriction on the distance that a particle can escape without deletion, which reduces the effectiveness of the method. The non-overlapping concept judges the suitability of potential new particles based on information already contained within the particle representation of the surface. By preventing the misplacement of particles it is possible to significantly relax the distance restriction thereby increasing the accuracy of the HPLS method in multi-phase flows. To demonstrate its robustness and efficiency, the concept is examined with a number of challenging test cases, including both level-set-only simulations and two-phase fluid flows.

Archer, Philip J.; Bai, Wei

2015-02-01

327

Fabrication of the multi-level phase type hologram for display using the laser direct write lithography system  

NASA Astrophysics Data System (ADS)

Recently, the demand to the diffractive optical element (DOE) is increasing with the developments in the technology. We created a relative large holographic optical element (HOE) with same course of production of the DOE. To make the person who is situated on the long distance recognize image data using the hologram, the hologram must have bright image reconstruction ability and a high SN ratio. Therefore, we made the multi-level phase type hologram for the former and measured the optical intensity of the reproduction image. For an evaluation method of the diffraction efficiency, we used 2-, 4-, and 8-level phase type Fresnel Zone Plate (FZP). Because it supposed that the amount of object was large, it adopted a computer-generated hologram (CGH). Also, it used laser direct write lithography system that has the feature of high-resolution drawing, high-speed drawing, and a high accuracy positioning system, for the making of hologram.

Nakano, Seiji; Nakahara, Sumio; Singubara, Shoso

2012-03-01

328

University of Maryland Technical Report UMIACS-TR-2012-11 Multi-Level Cache Resizing  

E-print Network

-level cache resizing (MCR). MCR independently resizes all caches in a modern cache hi- erarchy to minimize-optimal version of MCR, and find resizing a 3-level hierarchy can reduce total energy dissipation by 58 automatically find good size configurations at runtime. Our results show dynamic MCR can achieve between 40

Yeung, Donald

329

A SOA based framework for multi-level users oriented training courses for digitalized substation  

Microsoft Academic Search

Operators for digitalized substation differ in age, education and working experience, so it is hard to provide a universal set of courses for all. A framework based on Service Oriented Architecture (SOA) is proposed. Aiming at different level users, multiple similar services form a Differential Services Cluster (DSC), providing different courses by merging contents of courses through a Level Oriented

Du Li-min; Zhang Yong; Kuang Shi

2010-01-01

330

Shared inverter residential photovoltaic system concept  

NASA Astrophysics Data System (ADS)

A residential photovoltaic system concept involving a number of separate roof mounted arrays all connected to a single utility interactive inverter is proposed and analyzed to compare systems employing one inverter for each array. The significance is that such shared inverter systems offer a costs savings of approximately 10%. It is observed that other substantial benefits might derive from a reduction in the number of tie in points between distributed generators and the electric utility grid.

Kern, E. C.; Solman, F. J.

1981-11-01

331

Development of a grid connected photovoltaic power conditioning system based on flying capacitors inverter  

Microsoft Academic Search

In an effort to utilize the solar energy effectively through power electronics converters (conditioners), a great deal of research is being carried out to meet the increasing demand for load. This paper proposes an experimental photovoltaic (PV) power conditioning system with line connection. The conditioner consists of a flying capacitors multi-cell inverter fed by a dc-dc boost converter. The boost

M. Trabelsi; L. Ben-Brahim

2011-01-01

332

Fractal multi-level organisation of human groups in a virtual world  

E-print Network

Humans are fundamentally social. They have progressively dominated their environment by the strength and creativity provided by and within their grouping. It is well recognised that human groups are highly structured, and the anthropological literature has loosely classified them according to their size and function, such as support cliques, sympathy groups, bands, cognitive groups, tribes, linguistic groups and so on. Recently, combining data on human grouping patterns in a comprehensive and systematic study, Zhou et al. identified a quantitative discrete hierarchy of group sizes with a preferred scaling ratio close to $3$, which was later confirmed for hunter-gatherer groups and for other mammalian societies. Using high precision large scale Internet-based social network data, we extend these early findings on a very large data set. 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 a massive m...

Fuchs, Benedikt; Thurner, Stefan

2014-01-01

333

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

334

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

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

2014-08-13

335

Organic light emitting complementary inverters  

NASA Astrophysics Data System (ADS)

We show that p- and n-type light emitting field-effect transistors (LEFETs) can be made using "superyellow" as a light-emitting polymer, poly(2,5-bis(3-tetradecylthiophen-2-yl)thieno[3,2-b]thiophene) as a p-type material and a naphthalene di-imide as an n-type material. By connecting two of these LEFETs, we have demonstrated a light emitting complementary inverter (LECI). The LECI exhibited electrical and optical characteristics in the first and third quadrant of the transfer characteristics with voltage gain of 6 and 8, respectively.

Namdas, Ebinazar B.; Samuel, Ifor D. W.; Shukla, Deepak; Meyer, Dianne M.; Sun, Yanming; Hsu, Ben B. Y.; Moses, Daniel; Heeger, Alan J.

2010-01-01

336

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

E-print Network

features computed per voxel to generate a GGN class-conditional probability map. GGN candi- dates at voxel-level is difficult for both computers and radiologists, with high inter- and intra-person errors

Corso, Jason J.

337

Community environments and walking-to-school behaviors: multi-level correlates and underlying disparities  

E-print Network

effective interventions. This is a cross-sectional study of 73 public elementary schools in the Austin Independent School District of Texas. The first phase used geographic information systems and field audits to examine school-level disparities...

Zhu, Xuemei

2009-05-15

338

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

Microsoft Academic Search

Progress towards climate change aware regional sustainable development is affected by actions at multiple spatial scales and\\u000a governance levels and equally impacts actions at these scales. Many authors and policy practitioners consider therefore that\\u000a decisions over policy, mitigation strategies and capacity for adaptation to climate change require construction and coordination\\u000a over multiple levels of governance to arrive at acceptable local,

Katherine A. Daniell; María A. Máñez Costa; Nils Ferrand; Ashley B. Kingsborough; Peter Coad; Irina S. Ribarova

2011-01-01

339

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

340

Role of human sec63 in modulating the steady-state levels of multi-spanning membrane proteins.  

PubMed

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

Mades, Andreas; Gotthardt, Katherina; Awe, Karin; Stieler, Jens; Döring, Tatjana; Füser, Sabine; Prange, Reinhild

2012-01-01

341

Inverted OLEDs for flexible displays  

NASA Astrophysics Data System (ADS)

We reported a couple of methods to improve electron injection from the ITO electrode, thereby to fabricate efficient inverted bottom emission organic light emitting diodes (IBOLEDs). The first method is to use an n-doped electron transporting layer (ETL) as the electron injection layer. Electron only device characteristics and UPS measurements confirmed that B3PYMPM homo-junction has the lowest injection barrier at the interface among three different ETLs, resulting in the highest maximum EQE of 19.8% at low voltage in IBOLEDs. The energy barrier between n-ETL and ETL is one of the most important factors for high performance inverted OLEDs. The second method is to use an organic p-n junction as an electron injection layer, where the p-n junction generated electrons and holes under reverse bias, which corresponds to the forward bias in the OLEDs. The organic p-n junction composed of a p-CuPc/n-Bphen layer shows almost the same electron injection characteristics for the cathodes with different work functions whereas the injection characteristics of the n-Bphen EIL significantly depend on the work function of the cathode. These facts indicate that the organic p-n junction can be efficiently applied as an electron injection layer for high performance flexible organic electronics, regardless of the electrodes.

Kim, Jang-Joo; Lee, Jeong-Hwan; Kim, Ji Whan; Kim, Sei-Yong; Yoo, Seung-Jun; Wang, Po-Sheng; Wu, Chih-I.

2012-09-01

342

An inverted pendulum with a springy control as a model of human standing  

E-print Network

The normal and the inverted pendulum continue to be one of the main physical models and metaphors in science. The inverted pendulum is also a classic study case in control theory. In this paper we consider a special demonstration version of the inverted pendulum which is controlled via a spring. If the spring constant is below a critical level the springy control will be unstable and the pendulum will be kept from falling only by exercising a dynamically varying control. This situation resembles the case of human bipedal quiet standing with the Achilles tendon serving as the spring. The paper is written with physics students in mind.

Borg, F

2005-01-01

343

Advances in series resonant inverter technology and its effect on spacecraft employing electric propulsion  

NASA Technical Reports Server (NTRS)

The efficiency of transistorized Series Resonant Inverters (SRIs), which is higher than that of silicon-controlled rectifier alternatives, reduces spacecraft radiator requirements by 40% and may eliminate the need for heat pipes on 30-cm ion thruster systems. Recently developed 10- and 25-kW inverters have potential applications in gas thrusters, and represent the first spaceborne SRI designs for such power levels. Attention is given to the design and control system approaches employed in these inverter designs to improve efficiency and reduce weight, along with the impact of such improved parameters on electric propulsion systems.

Robson, R. R.

1982-01-01

344

toyLIFE: a computational framework to study the multi-level organisation of the genotype-phenotype map  

PubMed Central

The genotype-phenotype map is an essential object to understand organismal complexity and adaptability. However, its experimental characterisation is a daunting task. Thus, simple models have been proposed and investigated. They have revealed that genotypes differ in their robustness to mutations; phenotypes are represented by a broadly varying number of genotypes, and simple point mutations suffice to navigate the space of genotypes while maintaining a phenotype. Nonetheless, most current models focus only on one level of the map (folded molecules, gene regulatory networks, or networks of metabolic reactions), so that many relevant questions cannot be addressed. Here we introduce toyLIFE, a multi-level model for the genotype-phenotype map based on simple genomes and interaction rules from which a complex behaviour at upper levels emerges —remarkably plastic gene regulatory networks and metabolism. toyLIFE is a tool that permits the investigation of how different levels are coupled, in particular how and where mutations affect phenotype or how the presence of certain metabolites determines the dynamics of toyLIFE gene regulatory networks. The model can easily incorporate evolution through more complex mutations, recombination, or gene duplication and deletion, thus opening an avenue to explore extended genotype-phenotype maps. PMID:25520296

Arias, Clemente F.; Catalán, Pablo; Manrubia, Susanna; Cuesta, José A.

2014-01-01

345

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.

Oberdörster, Alexander; Brückner, Andreas; Lensch, Hendrik P. A.

2014-09-01

346

What's Driving You Crazy? A Question To Drive Collaborative, Inquiry-Based Middle School Reform. Part II: Private and Multi-Level Schools.  

ERIC Educational Resources Information Center

Describes how the question "What's driving you crazy?" is used by Hawaii middle-level educators to improve working conditions and meet students' needs by making schools more developmentally responsive. Focuses on the 6-step collaborative, inquiry-based innovation process at two private, multi-level schools embedded within K-8 or 6-12 campuses.…

Deering, Paul D.; And Others

2003-01-01

347

Design of Self Compensated Non Contact Capacitive Sensors and Proficient Signal Conditioning Circuit for Multi Threshold Liquid Level Control -A Novel Approach  

Microsoft Academic Search

An innovative method for self-compensating capacitive sensor for multi threshold liquid level measurement is presented in this work. Presently it is a trend to design and develop non -contact type sensors for the measurement and control of liquid level, since chemicals in industry can corrode the sensors in contact used for the monitoring purpose. In practice the sensors are to

C. S. S. Babu; D. H. Somesh

2006-01-01

348

On combining multi-normalization and ancillary measures for the optimal score level fusion of fingerprint and voice biometrics  

NASA Astrophysics Data System (ADS)

In this paper, we have considered the utility of multi-normalization and ancillary measures, for the optimal score level fusion of fingerprint and voice biometrics. An efficient matching score preprocessing technique based on multi-normalization is employed for improving the performance of the multimodal system, under various noise conditions. Ancillary measures derived from the feature space and the score space are used in addition to the matching score vectors, for weighing the modalities, based on their relative degradation. Reliability (dispersion) and the separability (inter-/intra-class distance and d-prime statistics) measures under various noise conditions are estimated from the individual modalities, during the training/validation stage. The `best integration weights' are then computed by algebraically combining these measures using the weighted sum rule. The computed integration weights are then optimized against the recognition accuracy using techniques such as grid search, genetic algorithm and particle swarm optimization. The experimental results show that, the proposed biometric solution leads to considerable improvement in the recognition performance even under low signal-to-noise ratio (SNR) conditions and reduces the false acceptance rate (FAR) and false rejection rate (FRR), making the system useful for security as well as forensic applications.

Mohammed Anzar, Sharafudeen Thaha; Sathidevi, Puthumangalathu Savithri

2014-12-01

349

A multi-level buck converter based rectifier with sinusoidal inputs and unity power factor for medium voltage (4160-7200 V) applications  

Microsoft Academic Search

A novel rectifier topology for high power (0.5 to 10 MVA) current source based AC motor drives is proposed. This rectifier is composed of a multi-winding transformer, a multilevel diode rectifier and a multi-level buck converter. The rectifier produces near unity input power factor and sinusoidal input current under any operating conditions. In addition, the proposed rectifier has a few

M. L. Zhang; B. Wu; Y. Xiao; F. Dewinter; R. Sotudeh

1999-01-01

350

Water in the Middle East, a Secondary and College Level Multi-Media Study.  

ERIC Educational Resources Information Center

The secondary and college level guide outlines a course of study on the Middle East, with emphasis on water problems of the area. Among the course objectives are the following: (1) make generalizations about particular Middle Eastern cultures and support them with evidence; (2) interpret environmental and social data from specific Middle Eastern…

Manneberg, Eliezer

351

Temporal and spectral investigation of multi-Landau level quantum beats in GaAs  

SciTech Connect

By resolving temporally and spectrally transient four-wave-mixing, the authors observe multiple Landau level quantum beating in GaAs under 6T magnetic field. Excitation energy and density dependent quantum interference gives rise to non-periodic beats.

Siegner, U.; Mycek, M.A.; Chemla, D.S.

1994-05-01

352

Multi-Level Aspects of Social Cohesion of Secondary Schools and Pupils' Feelings of Safety  

ERIC Educational Resources Information Center

Background: School safety and corresponding feelings of both pupils and school staff are beginning to receive more and more attention. The social cohesion characteristics of a school may be useful in promoting feelings of safety, particularly in pupils. Aims: To conceptualize theoretically, and check empirically a two-level model of social…

Mooij, Ton; Smeets, Ed; de Wit, Wouter

2011-01-01

353

Can User-Level Protocols Take Advantage of Multi-CPU NICs? Piyush Shivam  

E-print Network

of a range of user-level network protocols: FM [7] for Myrinet, UNet [14] for ATM and Fast Ethernet, GM [2 Gigabit Ethernet NICs includes two CPUs, though. This raises an open chal- lenge whether performance] for Myrinet, our recent work on EMP [10] for Gigabit Ethernet, etc. 1 Dur- ing the last few years, the designs

Panda, Dhabaleswar K.

354

Evaluating the Impacts of ICT Use: A Multi-Level Analysis with Hierarchical Linear Modeling  

ERIC Educational Resources Information Center

The purpose of this study is to evaluate the impacts of ICT use on achievements by considering not only ICT use, but also the process and background variables that influence ICT use at both the student- and school-level. This study was conducted using data from the 2010 Survey of Seoul Education Longitudinal Research. A Hierarchical Linear…

Song, Hae-Deok; Kang, Taehoon

2012-01-01

355

Automatic data movement and computation mapping for multi-level parallel architectures with explicitly managed memories  

Microsoft Academic Search

Several parallel architectures such as GPUs and the Cell proces- sor have fast explicitly managed on-chip memories, in addition to slow off-chip memory. They also have very high computational power with multiple levels of parallelism. A signicant challenge in programming these architectures is to effectively exploit the par- allelism available in the architecture and manage the fast memories to maximize

Muthu Manikandan Baskaran; Uday Bondhugula; Sriram Krishnamoorthy; J. Ramanujam; Atanas Rountev; P. Sadayappan

2008-01-01

356

Overpopulation, Gender Differences and Cultural Attitudes: A Multi-level Lesson Plan for (ESL) College Students.  

ERIC Educational Resources Information Center

Provides a number of reading and discussion exercises on issue-oriented questions (such as "overpopulation") that may be used for just about any level of English-as-a-Second-Language instruction. Suggests a role-play exercise in imitation of the television show "Dating Game." (TB)

Miles, Norma D.

1996-01-01

357

The impact of information sharing strategies in multi-level supply chain  

Microsoft Academic Search

Information sharing is a major strategy to counteract the bullwhip effect. Previous research suggested that applying different ISS (information sharing strategy) to the supply chain may improve the supply chain performance under a simplified two-level supply chain model. In this paper, we present a simulation study that investigates the effectiveness of information sharing under different information sharing strategy scenarios within

Xiongwei Zhou; Feicheng Ma; Ling Zhang; Xueying Wang

2008-01-01

358

Accountability and Alignment under No Child Left Behind: Multi-Level Perspectives for Educational Leaders  

ERIC Educational Resources Information Center

Educational leaders have faced the challenges of trying to align schoolwide reforms priorities with accountability demands under the No Child Left Behind law. This article examines the barriers that complicate meaningful alignment among federal, state and local levels. This article also offers the following recommendations: Schools and districts…

Choi, Daniel

2011-01-01

359

Multi-Level Coding Efficiency with Improved Quality for Image Compression based on AMBTC  

E-print Network

In this paper, we have proposed an extended version of Absolute Moment Block Truncation Coding (AMBTC) to compress images. Generally the elements of a bitplane used in the variants of Block Truncation Coding (BTC) are of size 1 bit. But it has been extended to two bits in the proposed method. Number of statistical moments preserved to reconstruct the compressed has also been raised from 2 to 4. Hence, the quality of the reconstructed images has been improved significantly from 33.62 to 38.12 with the increase in bpp by 1. The increased bpp (3) is further reduced to 1.75in multiple levels: in one level, by dropping 4 elements of the bitplane in such a away that the pixel values of the dropped elements can easily be interpolated with out much of loss in the quality, in level two, eight elements are dropped and reconstructed later and in level three, the size of the statistical moments is reduced. The experiments were carried over standard images of varying intensities. In all the cases, the proposed method outp...

Somasundaram, Dr K

2012-01-01

360

A feedback linearizing control scheme for a PWM converter-inverter having a very small DC-link capacitor  

Microsoft Academic Search

This paper addresses a control method of reducing the size of the DC-link capacitors of a converter-inverter system. The main idea is to utilize the inverter operation status in the current control of the converter. Specifically, the information on the load power is incorporated in synthesizing the converter current control input so that a proper DC voltage level is maintained.

Jinhwan Jung; Sunkyoung Lim; Kwanghee Nam

1999-01-01

361

A machine learning approach to multi-level ECG signal quality classification.  

PubMed

Current electrocardiogram (ECG) signal quality assessment studies have aimed to provide a two-level classification: clean or noisy. However, clinical usage demands more specific noise level classification for varying applications. This work outlines a five-level ECG signal quality classification algorithm. A total of 13 signal quality metrics were derived from segments of ECG waveforms, which were labeled by experts. A support vector machine (SVM) was trained to perform the classification and tested on a simulated dataset and was validated using data from the MIT-BIH arrhythmia database (MITDB). The simulated training and test datasets were created by selecting clean segments of the ECG in the 2011 PhysioNet/Computing in Cardiology Challenge database, and adding three types of real ECG noise at different signal-to-noise ratio (SNR) levels from the MIT-BIH Noise Stress Test Database (NSTDB). The MITDB was re-annotated for five levels of signal quality. Different combinations of the 13 metrics were trained and tested on the simulated datasets and the best combination that produced the highest classification accuracy was selected and validated on the MITDB. Performance was assessed using classification accuracy (Ac), and a single class overlap accuracy (OAc), which assumes that an individual type classified into an adjacent class is acceptable. An Ac of 80.26% and an OAc of 98.60% on the test set were obtained by selecting 10 metrics while 57.26% (Ac) and 94.23% (OAc) were the numbers for the unseen MITDB validation data without retraining. By performing the fivefold cross validation, an Ac of 88.07±0.32% and OAc of 99.34±0.07% were gained on the validation fold of MITDB. PMID:25306242

Li, Qiao; Rajagopalan, Cadathur; Clifford, Gari D

2014-12-01

362

Stroboscopic study of the inverted pendulum  

Microsoft Academic Search

A portable jigsaw is adapted to provide an inexpensive large-scale demonstration of the inverted pendulum experiment. Stroboscopic study reveals interesting features of the motion of the inclined pendulum, as well as the possibility that no pendulum is ever quite inverted. Kalmus [Am. J. Phys. 38, 874 (1970)] and Kapitza [Collected Papers by P. L. Kapitza, edited by D. TerHaar (Pergamon,

M. M. Michaelis

1985-01-01

363

A Multi-Level Geographical Study of Italian Political Elections from Twitter Data  

PubMed Central

In this paper we present an analysis of the behavior of Italian Twitter users during national political elections. We monitor the volumes of the tweets related to the leaders of the various political parties and we compare them to the elections results. Furthermore, we study the topics that are associated with the co-occurrence of two politicians in the same tweet. We cannot conclude, from a simple statistical analysis of tweet volume and their time evolution, that it is possible to precisely predict the election outcome (or at least not in our case of study that was characterized by a “too-close-to-call” scenario). On the other hand, we found that the volume of tweets and their change in time provide a very good proxy of the final results. We present this analysis both at a national level and at smaller levels, ranging from the regions composing the country to macro-areas (North, Center, South). PMID:24802857

Caldarelli, Guido; Chessa, Alessandro; Pammolli, Fabio; Pompa, Gabriele; Puliga, Michelangelo; Riccaboni, Massimo; Riotta, Gianni

2014-01-01

364

Circadian rhythms and mood: Opportunities for multi-level analyses in genomics and neuroscience  

PubMed Central

In the healthy state, both circadian rhythm and mood are stable against perturbations, yet they are capable of adjusting to altered internal cues or ongoing changes in external conditions. The dual demands of stability and flexibility are met by the collective properties of complex neural networks. Disruption of this balance underlies both circadian rhythm abnormality and mood disorders. However, we do not fully understand the network properties that govern the crosstalk between the circadian system and mood regulation. This puzzle reflects a challenge at the center of neurobiology, and its solution requires the successful integration of existing data across all levels of neural organization, from molecules, cells, circuits, network dynamics, to integrated mental function. This essay discusses several open questions confronting the cross-level synthesis, and proposes that circadian regulation, and its role in mood, stands as a uniquely tractable system to study the causal mechanisms of neural adaptation. PMID:24853393

Li, Jun Z

2014-01-01

365

Simulating multi-decadal variability of Caspian Sea level changes using regional climate model outputs  

Microsoft Academic Search

The Caspian Sea is the largest enclosed body of water on earth, covering approximately 4×105 km2 and sharing its coast with five countries (Iran, Azerbaijan, Kazakhstan, Russia and Turkmenistan). Because it has no outlet\\u000a to the ocean the Caspian Sea level (CSL) has undergone rapid shifts in response to climatic forcings, and these have been\\u000a devastating for the surrounding countries. In

N. Elguindi; F. Giorgi

2006-01-01

366

Evaluation of empirical mode decomposition for quantifying multi-decadal variations in sea level records  

NASA Astrophysics Data System (ADS)

The ability of empirical mode decomposition (EMD) to extract multidecadal variability from sea level records is tested using three simulations: one based on a series of purely sinusoidal modes, one based on scaled climate indices of El Niño and the Pacific Decadal Oscillation (PDO), and the final one including a single month with an extreme sea level event. All simulations include random noise of similar variance to high-frequency variability in the San Francisco tide gauge record. The intrinsic mode functions (IMFs) computed using EMD were compared to the prescribed oscillations. In all cases, the longest-period modes are significantly distorted, with incorrect amplitudes and phases. This affects the estimated acceleration computed from the longest periodic IMF. In these simulations, the acceleration was underestimated in the case with purely sinusoidal modes, and overestimated by nearly 100% in the case with prescribed climate modes. Additionally, in all cases, extra low-frequency modes uncorrelated with the prescribed variability are found. These experiments suggest that using EMD to identify multidecadal variability and accelerations in sea level records should be used with caution.

Chambers, D. P.

2014-12-01

367

Novel H-bridge multilevel current-source PWM inverter with inductor-cells  

Microsoft Academic Search

The paper proposes a new circuit configuration of multilevel current-source inverter (CSI). In this new topology, a basic H-Bridge CSI working as a main inverter is connected in parallel with inductor-cells operated as auxiliary circuits. The inductor cell is composed by four unidirectional power switches with an inductor across the cell circuit. The inductor-cells work generating the intermediate level currents

S. Suroso; T. Noguchi

2010-01-01

368

Voltage-Balancing Circuit Based on a Resonant Switched-Capacitor Converter for Multilevel Inverters  

Microsoft Academic Search

This paper proposes a new voltage-balancing circuit for the split dc voltages in a diode-clamped five-level inverter. The proposed circuit is based on a resonant switched-capacitor converter (RSCC), which consists of two half-bridge inverters, a resonant inductor, and a resonant capacitor. A new phase-shift control of the RSCC is proposed to improve voltage-balancing performance. As a result, it is possible

Kenichiro Sano; Hideaki Fujita

2008-01-01

369

Design of an IGBT-based LCL-resonant inverter for high-frequency induction heating  

Microsoft Academic Search

A power electronic inverter is developed for a high-frequency induction heating application. The application requires up to 160 kW of power at a frequency of 100 kHz. This power-frequency product represents a significant challenge for today's power semiconductor technology. Voltage source and current source inverters both using ZCS or ZVS are analyzed and compared. To attain the level of performance

Sibylle Dieckerhoff; M. J. Ruan; Rik W. De Doncker

1999-01-01

370

A SiC MOSFET Based Inverter for Wireless Power Transfer Applications  

SciTech Connect

In a wireless power transfer (WPT) system, efficiency of the power conversion stages is crucial so that the WPT technology can compete with the conventional conductive charging systems. Since there are 5 or 6 power conversion stages, each stage needs to be as efficient as possible. SiC inverters are crucial in this case; they can handle high frequency operation and they can operate at relatively higher temperatures resulting in reduces cost and size for the cooling components. This study presents the detailed power module design, development, and fabrication of a SiC inverter. The proposed inverter has been tested at three center frequencies that are considered for the WPT standardization. Performance of the inverter at the same target power transfer level is analyzed along with the other system components. In addition, another SiC inverter has been built in authors laboratory by using the ORNL designed and developed SiC modules. It is shown that the inverter with ORNL packaged SiC modules performs simular to that of the inverter having commercially available SiC modules.

Onar, Omer C [ORNL] [ORNL; Chinthavali, Madhu Sudhan [ORNL] [ORNL; Campbell, Steven L [ORNL] [ORNL; Ning, Puqi [Chinese Academy of Sciences (CAS)] [Chinese Academy of Sciences (CAS); White, Cliff P [ORNL] [ORNL; Miller (JNJ), John M. [JNJ-Miller PLC] [JNJ-Miller PLC

2014-01-01

371

Response to Natural Hazards: Multi-Level Governance Challenges in Newfoundland & Labrador, Canada  

NASA Astrophysics Data System (ADS)

Newfoundland and Labrador's perspective on emergency measures in response to natural hazards is shaped by several factors. Climate, meteorology, and terrain are the dominant factors both in the occurrence of events and the responses to them. The economy, dominated by resource-based activities, is a significant influence in accentuating exposure to natural hazards. In this situation, the role of earth scientists is critical. However, effective input from geographers, geomorphologists, and climatologists requires an understanding of the governance regime. For emergency services, both formal public policy responses, informal mechanisms, and the interfacing that exists between public policy mechanisms and social forces are significant. In an era where more and more problems are considered as "interdependent", and require different governmental, social, and professional expertise forces to come together to address objectives, there is interest in exploring and analyzing patterns of communication, interactions and policy learning across inherited silos. A major political-policy struggle is the challenge of managing rural-urban differences in capacity and perspective. Another challenge involves finding ways for professions to merge their protocols and cultures. Embracing best practices associated with natural hazards and emergency preparedness is influenced by the power and independence of various groups involved. Critical events provide windows of opportunity for urging new approaches, but whether these become institutionalized or not normally depends on the interplay of ideas, interests, individuals, and institutions. In coping with natural hazards, renewing governance required finding new incentives to integrate across jurisdictions and disciplinary and governmental-society boundaries. Perception and response to natural hazards is very much connected with the historical-policy context. The pace of effective response indicates the impact of culture, capacity, institutions, and interests in the struggle to shift priorities, especially if these are being imposed externally. Emergency planning involves contestation, shifting priorities, building knowledge capacity, and merging policy and jurisdictional networks based on best practices. It requires renewing governance, coordinating planning, data collection, building infrastructure and establishing a common vision where different interests can work together to promote common values and objectives. However, emergency planning is difficult to change and reform based on a common vision and approach, because the inherited formal and informal structures tend to be very complex multi-disciplinary systems. Not only does this pose difficulties in renewing governance, establishing clear lines of authority, and responsibility across jurisdictions, it is very difficult for previously unrecognized groups to participate. Natural hazard researchers, unfortunately, frequently fit into this latter category.

Catto, N.; Tomblin, S.

2009-04-01

372

Real-time multi-step-ahead water level forecasting by recurrent neural networks for urban flood control  

NASA Astrophysics Data System (ADS)

Urban flood control is a crucial task, which commonly faces fast rising peak flows resulting from urbanization. To mitigate future flood damages, it is imperative to construct an on-line accurate model to forecast inundation levels during flood periods. The Yu-Cheng Pumping Station located in Taipei City of Taiwan is selected as the study area. Firstly, historical hydrologic data are fully explored by statistical techniques to identify the time span of rainfall affecting the rise of the water level in the floodwater storage pond (FSP) at the pumping station. Secondly, effective factors (rainfall stations) that significantly affect the FSP water level are extracted by the Gamma test (GT). Thirdly, one static artificial neural network (ANN) (backpropagation neural network-BPNN) and two dynamic ANNs (Elman neural network-Elman NN; nonlinear autoregressive network with exogenous inputs-NARX network) are used to construct multi-step-ahead FSP water level forecast models through two scenarios, in which scenario I adopts rainfall and FSP water level data as model inputs while scenario II adopts only rainfall data as model inputs. The results demonstrate that the GT can efficiently identify the effective rainfall stations as important inputs to the three ANNs; the recurrent connections from the output layer (NARX network) impose more effects on the output than those of the hidden layer (Elman NN) do; and the NARX network performs the best in real-time forecasting. The NARX network produces coefficients of efficiency within 0.9-0.7 (scenario I) and 0.7-0.5 (scenario II) in the testing stages for 10-60-min-ahead forecasts accordingly. This study suggests that the proposed NARX models can be valuable and beneficial to the government authority for urban flood control.

Chang, Fi-John; Chen, Pin-An; Lu, Ying-Ray; Huang, Eric; Chang, Kai-Yao

2014-09-01

373

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

E-print Network

the greater their longevity (Rogers, Hummer and Nam 2000). Many scholars shy away from the impact that spirituality has on longevity. They are hesitant to point to faith as the factor that decreases the religious person’s risk of mortality. But some... to year. As of 1995 they were monitoring a core list including 615 chemicals, though over 8000 hazardous chemicals have been identified as being released by manufacturing facilities (Thomas and Qin 2001). The state-level data set also included two...

Lewinski, Christi Nicole

2007-09-17

374

Multi-Level Adaptive Techniques (MLAT) for singular-perturbation problems  

NASA Technical Reports Server (NTRS)

The multilevel (multigrid) adaptive technique, a general strategy of solving continuous problems by cycling between coarser and finer levels of discretization is described. It provides very fast general solvers, together with adaptive, nearly optimal discretization schemes. In the process, boundary layers are automatically either resolved or skipped, depending on a control function which expresses the computational goal. The global error decreases exponentially as a function of the overall computational work, in a uniform rate independent of the magnitude of the singular-perturbation terms. The key is high-order uniformly stable difference equations, and uniformly smoothing relaxation schemes.

Brandt, A.

1978-01-01

375

Multi-level slug tests in highly permeable formations: 1. Modification of the Springer-Gelhar (SG) model  

USGS Publications Warehouse

A multi-level slug test model and a method for the evaluation of vertical profiles of hydraulic conductivity in highly permeable formations are developed. A double-packer system is employed to estimate local hydraulic conductivity. Depending on the formation and double-packer system parameters, the water level recovery in the tested well can exhibit a monotonic or oscillatory response. To discern information on aquifer properties from artifacts introduced by the measurement system, the theory of flow in an aquifer and a double-packer system is developed. The mathematical model incorporates features of the Springer and Gelhar (1991) model and reduces to the Bouwer and Rice (1976) model in a special case. The model involves equations of momentum and mass conservation for the double-packer system with quasi-steady well-aquifer interaction equations. The method is uniformly applicable for both monotonic and oscillatory well responses and can produce profiles of hydraulic conductivity for the tested well. The criterion is given to determine the type of well response for given slug test conditions.A multi-level slug test model and a method for the evaluation of vertical profiles of hydraulic conductivity in highly permeable formations are developed. A double-packer system is employed to estimate local hydraulic conductivity. Depending on the formation and double-packer system parameters, the water level recovery in the tested well can exhibit a monotonic or oscillatory response. To discern information on aquifer properties from artifacts introduced by the measurement system, the theory of flow in an aquifer and a double-packer system is developed. The mathematical model incorporates features of the Springer and Gelhar (1991) model and reduces to the Bouwer and Rice (1976) model in a special case. The model involves equations of momentum and mass conservation for the double-packer system with quasi-steady well-aquifer interaction equations. The method is uniformly applicable for both monotonic and oscillatory well responses and can produce profiles of hydraulic conductivity for the tested well. The criterion is given to determine the type of well response for given slug test conditions.

Zlotnik, V.A.; McGuire, V.L.

1998-01-01

376

The principle of coherence in multi-level brain information processing.  

PubMed

Synchronisation has become one of the major scientific tools to explain biological order at many levels of organisation. In systems neuroscience, synchronised subthreshold and suprathreshold oscillatory neuronal activity within and between distributed neuronal assemblies is acknowledged as a fundamental mode of neuronal information processing. Coherent neuronal oscillations correlate with all basic cognitive functions, mediate local and long-range neuronal communication and affect synaptic plasticity. However, it remains unclear how the very fast and complex changes of functional neuronal connectivity necessary for cognition, as mediated by dynamic patterns of neuronal synchrony, could be explained exclusively based on the well-established synaptic mechanisms. A growing body of research indicates that the intraneuronal matrix, composed of cytoskeletal elements and their binding proteins, structurally and functionally connects the synapses within a neuron, modulates neurotransmission and memory consolidation, and is hypothesised to be involved in signal integration via electric signalling due to its charged surface. Theoretical modelling, as well as emerging experimental evidence indicate that neuronal cytoskeleton supports highly cooperative energy transport and information processing based on molecular coherence. We suggest that long-range coherent dynamics within the intra- and extracellular filamentous matrices could establish dynamic ordered states, capable of rapid modulations of functional neuronal connectivity via their interactions with neuronal membranes and synapses. Coherence may thus represent a common denominator of neurophysiological and biophysical approaches to brain information processing, operating at multiple levels of neuronal organisation, from which cognition may emerge as its cardinal manifestation. PMID:22986048

Plankar, Matej; Brežan, Simon; Jerman, Igor

2013-01-01

377

A complete, multi-level conformational clustering of antibody complementarity-determining regions  

PubMed Central

Classification of antibody complementarity-determining region (CDR) conformations is an important step that drives antibody modelling and engineering, prediction from sequence, directed mutagenesis and induced-fit studies, and allows inferences on sequence-to-structure relations. Most of the previous work performed conformational clustering on a reduced set of structures or after application of various structure pre-filtering criteria. In this study, it was judged that a clustering of every available CDR conformation would produce a complete and redundant repertoire, increase the number of sequence examples and allow better decisions on structure validity in the future. In order to cope with the potential increase in data noise, a first-level statistical clustering was performed using structure superposition Root-Mean-Square Deviation (RMSD) as a distance-criterion, coupled with second- and third-level clustering that employed Ramachandran regions for a deeper qualitative classification. The classification of a total of 12,712 CDR conformations is thus presented, along with rich annotation and cluster descriptions, and the results are compared to previous major studies. The present repertoire has procured an improved image of our current CDR Knowledge-Base, with a novel nesting of conformational sensitivity and specificity that can serve as a systematic framework for improved prediction from sequence as well as a number of future studies that would aid in knowledge-based antibody engineering such as humanisation. PMID:25071986

Nikoloudis, Dimitris; Pitts, Jim E.

2014-01-01

378

Multi-level examination of correlates of active transportation to school among youth living within 1 mile of their school  

PubMed Central

Background Active transportation to school is a method by which youth can build physical activity into their daily routines. We examined correlates of active transportation to school at both individual- (characteristics of the individual and family) and area- (school and neighborhood) levels amongst youth living within 1 mile (1.6?km) of their school. Methods Using the 2009/10 Canadian Health Behaviour in School-Aged Children (HBSC) survey, we selected records of students (n?=?3 997) from 161 schools that resided in an urban setting and lived within 1 mile from their school. Student records were compiled from: (1) individual-level HBSC student questionnaires; (2) area-level administrator (school) questionnaires; and (3) area-level geographic information system data sources. The outcome, active transportation to school, was determined via a questionnaire item describing the method of transportation that individual students normally use to get to school. Analyses focused on factors at multiple levels that potentially contribute to student decisions to engage in active transportation. Multi-level logistic regression analyses were employed. Results Approximately 18% of the variance in active transportation was accounted for at the area-level. Several individual and family characteristics were associated with engagement in active transportation to school including female gender (RR vs. males?=?0.86, 95% CI: 0.80-0.91), having ?2 cars in the household (RR vs. no cars?=?0.87, 0.74-0.97), and family socioeconomic status (RR for ‘not well off’ vs. ‘very well off’?=?1.14, 1.01-1.26). Neighborhood characteristics most strongly related to active transportation were: the length of roads in the 1?km buffer (RR in quartile 4 vs. quartile 1?=?1.23, 1.00-1.42), the amount of litter in the neighborhood (RR for ‘major problem’ vs. ‘no problem’?=?1.47, 1.16-1.57), and relatively hot climates (RR in quartile 4 vs. quartile 1?=?1.33 CI, 1.05-1.53). Conclusion Engagement in active transportation to school was related to multiple factors at multiple levels. We identified gender, perception of residential neighborhood safety, the percentage of streets with sidewalks, and the total length of roads as the most important correlates of active transportation to school. PMID:23067247

2012-01-01

379

A multi-source satellite data approach for modelling Lake Turkana water level: calibration and validation using satellite altimetry data  

NASA Astrophysics Data System (ADS)

Lake Turkana is one of the largest desert lakes in the world and is characterized by high degrees of inter- and intra-annual fluctuations. The hydrology and water balance of this lake have not been well understood due to its remote location and unavailability of reliable ground truth datasets. Managing surface water resources is a great challenge in areas where in-situ data are either limited or unavailable. In this study, multi-source satellite-driven data such as satellite-based rainfall estimates, modelled runoff, evapotranspiration, and a digital elevation dataset were used to model Lake Turkana water levels from 1998 to 2009. Due to the unavailability of reliable lake level data, an approach is presented to calibrate and validate the water balance model of Lake Turkana using a composite lake level product of TOPEX/Poseidon, Jason-1, and ENVISAT satellite altimetry data. Model validation results showed that the satellite-driven water balance model can satisfactorily capture the patterns and seasonal variations of the Lake Turkana water level fluctuations with a Pearson's correlation coefficient of 0.90 and a Nash-Sutcliffe Coefficient of Efficiency (NSCE) of 0.80 during the validation period (2004-2009). Model error estimates were within 10% of the natural variability of the lake. Our analysis indicated that fluctuations in Lake Turkana water levels are mainly driven by lake inflows and over-the-lake evaporation. Over-the-lake rainfall contributes only up to 30% of lake evaporative demand. During the modelling time period, Lake Turkana showed seasonal variations of 1-2 m. The lake level fluctuated in the range up to 4 m between the years 1998-2009. This study demonstrated the usefulness of satellite altimetry data to calibrate and validate the satellite-driven hydrological model for Lake Turkana without using any in-situ data. Furthermore, for Lake Turkana, we identified and outlined opportunities and challenges of using a calibrated satellite-driven water balance model for (i) quantitative assessment of the impact of basin developmental activities on lake levels and for (ii) forecasting lake level changes and their impact on fisheries. From this study, we suggest that globally available satellite altimetry data provide a unique opportunity for calibration and validation of hydrologic models in ungauged basins.

Velpuri, N. M.; Senay, G. B.; Asante, K. O.

2012-01-01

380

Rapid and multi-level characterization of trastuzumab using sheathless capillary electrophoresis-tandem mass spectrometry  

PubMed Central

Monoclonal antibodies (mAbs) are highly complex proteins that display a wide range of microheterogeneity that requires multiple analytical methods for full structure assessment and quality control. As a consequence, the characterization of mAbs on different levels is particularly product - and time - consuming. This work presents the characterization of trastuzumab sequence using sheathless capillary electrophoresis (referred as CESI) – tandem mass spectrometry (CESI-MS/MS). Using this bottom-up proteomic-like approach, CESI-MS/MS provided 100% sequence coverage for both heavy and light chain via peptide fragment fingerprinting (PFF) identification. The result was accomplished in a single shot, corresponding to the analysis of 100 fmoles of digest. The same analysis also enabled precise characterization of the post-translational hot spots of trastuzumab, used as a representative widely marketed therapeutic mAb, including the structural confirmation of the five major N-glycoforms. PMID:23563524

Gahoual, Rabah; Burr, Alicia; Busnel, Jean-Marc; Kuhn, Lauriane; Hammann, Phillipe; Beck, Alain; François, Yannis-Nicolas; Leize-Wagner, Emmanuelle

2013-01-01

381

Probing single- to multi-cell level charge transport in Geobacter sulfurreducens DL-1  

NASA Astrophysics Data System (ADS)

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 DL-1 to elucidate the fundamental limits and factors determining maximum power output from a microbial fuel cell. Quantized stepwise current outputs of 92(±33) and 196(±20)?fA are generated from microelectrode arrays confined in isolated wells. Simultaneous cell imaging/tracking and current recording reveals that the current steps are directly correlated with the contact of one or two cells with the electrodes. This work establishes the amount of current generated by an individual Geobacter cell in the absence of a biofilm and highlights the potential upper limit of microbial fuel cell performance for Geobacter in thin biofilms.

Jiang, Xiaocheng; Hu, Jinsong; Petersen, Emily R.; Fitzgerald, Lisa A.; Jackan, Charles S.; Lieber, Alexander M.; Ringeisen, Bradley R.; Lieber, Charles M.; Biffinger, Justin C.

2013-11-01

382

Multi-level ecotoxicity assay on the aquatic midge, Chironomus tentans (Diptera, Chironomidae) exposed to octachlorostyrene.  

PubMed

Octachlorostyrene (OCS) is a ubiquitously distributed compound, of which, ecotoxicological property is little known. To investigate the ecotoxicity of OCS, short- and long-term experiments were conducted under controlled laboratory conditions, using the aquatic midge, Chironomus tentans, as a biological model system. Ecophysiological responses using organism/population level endpoints, such as growth, reproduction and development, were investigated. Moreover, oxidative stress-related parameters and the expression of heat shock protein and hemoglobin gene were also investigated as potential biomarkers for OCS exposure. Significant disturbance in male/female adult ratio and on oviposition by chronic exposure to OCS suggests that this compound may have serious consequences on Chironomus population by affecting reproduction. To elucidate the mechanism of these speculated phenomena, direct experimental demonstrations on the relationships between observed ecotoxicological response and upstream-induced molecular/biochemical events may be needed. PMID:21784015

Lee, Si-Won; Choi, Jinhee

2009-09-01

383

Stepping up ELISpot: Multi-Level Analysis in FluoroSpot Assays  

PubMed Central

ELISpot is one of the most commonly used immune monitoring assays, which allows the functional assessment of the immune system at the single cell level. With its outstanding sensitivity and ease of performance, the assay has recently advanced from the mere single function cell analysis to multifunctional analysis by implementing detection reagents that are labeled with fluorophores (FluoroSpot), allowing the detection of secretion patterns of two or more analytes in a single well. However, the automated evaluation of such assays presents various challenges for image analysis. Here we dissect the technical and methodological requirements for a reliable analysis of FluoroSpot assays, introduce important quality control measures and provide advice for proper interpretation of results obtained by automated imaging systems. PMID:25437440

Janetzki, Sylvia; Rueger, Markus; Dillenbeck, Tomas

2014-01-01

384

Stepping up ELISpot: Multi-Level Analysis in FluoroSpot Assays.  

PubMed

ELISpot is one of the most commonly used immune monitoring assays, which allows the functional assessment of the immune system at the single cell level. With its outstanding sensitivity and ease of performance, the assay has recently advanced from the mere single function cell analysis to multifunctional analysis by implementing detection reagents that are labeled with fluorophores (FluoroSpot), allowing the detection of secretion patterns of two or more analytes in a single well. However, the automated evaluation of such assays presents various challenges for image analysis. Here we dissect the technical and methodological requirements for a reliable analysis of FluoroSpot assays, introduce important quality control measures and provide advice for proper interpretation of results obtained by automated imaging systems. PMID:25437440

Janetzki, Sylvia; Rueger, Markus; Dillenbeck, Tomas

2014-01-01

385

Multi-level Association Rules and Directed Graphs for the Lagrangian Analysis of the Mediterranean Ocean Forecasting System (MFS)  

NASA Astrophysics Data System (ADS)

The Lagrangian method is one of basic methods for modeling the transport of water parcels and the dispersion of biological species. Lagrangian data analysis uses various tools which include classical statistics; however, a visual inspection of individual trajectories is also important for a first sight of the underlying dynamics. The difficulty of the analysis of a large number of trajectories and its visual presentation implies the need for more sophisticated methods. In this study we propose a new methodology which includes data mining and different visualization techniques, namely, association rules and directed graphs. Association rules mining is a representative of unsupervised data mining methods, used to find interesting and important relationships between subsets of attributes in large databases. Oceanographic data exhibit strong spatial and temporal dependencies, so we have extended the basic association rules discovery to spatial and temporal association rules mining. In addition, we need efficient methods for the visualization of the rules and thus we suggest a novel method which uses multi-level graphs with different levels of space and time granularity. Moreover, we can intertwine the knowledge from various disciplines related to oceanography, e.g. marine ecology, and form the graphs of connections among quantities with different granularity and refinement. The motivation for our work comes from the modeling of marine meta-populations where the persistence of local populations strongly depends on the topology and cycles of the connectivity networks. The results of first experiments with the Lagrangian trajectories obtained from the climatologically averaged results of the Adriatic Sea Forecasting System (AFS) show many similarities with previous findings concerning the circulation in the Adriatic Sea, especially regarding the currents along the Italian coast and cyclonic circulation in the southern Adriatic. In this study we present a case study on several thousands of Lagrangian trajectories, obtained from the velocity fields of the currents from the numerical results of the Mediterranean Ocean Forecasting System (MFS) during the period 1999-2011. We show the multi-level graphs derived from the given mass of trajectories, and demonstrate the usefulness of the algorithms on these graphs for the discovery of information from different branches of science that are related to oceanography. The association rules mining of graphs reveals typical frequent substructures of ocean circulation and assists in the identification of similar patterns of circulation during different seasons and year spans. Additionally we use the Markov models to find the distribution of particles, i.e., biological species, and their most probable paths in the model domain after a given number of time intervals. The aforementioned models can also show the degree of connectivity between different regions in the area of study.

Petelin, B.; Malacic, V.; Malej, A.; Kukar, M.; Kononenko, I.

2012-04-01

386

Multi-stage filtering for improving confidence level and determining dominant clusters in clustering algorithms of gene expression data.  

PubMed

A drastic improvement in the analysis of gene expression has lead to new discoveries in bioinformatics research. In order to analyse the gene expression data, fuzzy clustering algorithms are widely used. However, the resulting analyses from these specific types of algorithms may lead to confusion in hypotheses with regard to the suggestion of dominant function for genes of interest. Besides that, the current fuzzy clustering algorithms do not conduct a thorough analysis of genes with low membership values. Therefore, we present a novel computational framework called the "multi-stage filtering-Clustering Functional Annotation" (msf-CluFA) for clustering gene expression data. The framework consists of four components: fuzzy c-means clustering (msf-CluFA-0), achieving dominant cluster (msf-CluFA-1), improving confidence level (msf-CluFA-2) and combination of msf-CluFA-0, msf-CluFA-1 and msf-CluFA-2 (msf-CluFA-3). By employing double filtering in msf-CluFA-1 and apriori algorithms in msf-CluFA-2, our new framework is capable of determining the dominant clusters and improving the confidence level of genes with lower membership values by means of which the unknown genes can be predicted. PMID:23930805

Kasim, Shahreen; Deris, Safaai; Othman, Razib M

2013-09-01

387

Image quality improvements of electronic portal imaging devices by multi-level gain calibration and temperature correction  

NASA Astrophysics Data System (ADS)

Amorphous silicon (aSi:H) flat panel detectors are prevalent in radiotherapy for megavoltage imaging tasks. Any clinical and dosimetrical application requires a well-defined dose response of the system to achieve meaningful results. Due to radiation damages, panels deteriorate and the linearity of pixel response to dose as well as the stability with regard to changing operating temperatures get worse with time. Using a single level gain correction can lead to an error of about 23% when irradiating a flood field image with 100 MU min-1 on an old detector. A multi-level gain (MLG) correction is introduced, emending the nonlinearities and subpanel-related artifacts caused by insufficient radiation hardness of amplifiers in the read-out electronics. With rising temperature, offset values typically increase (up to 300 gray values) while the response at higher dose values per frame remain constant for a majority of pixels. To account for temperature-related image artifacts, two additional temperature correction methods have been developed. MLG in combination with temperature corrections can re-establish the aSi:H image quality to the performance required by reliable medical verification tools. Furthermore, the life span and recalibration intervals of these costly devices can be prolonged decisively.

Huber, S.; Mooslechner, M.; Mitterlechner, B.; Weichenberger, H.; Serpa, M.; Sedlmayer, F.; Deutschmann, H.

2013-09-01

388

Image quality improvements of electronic portal imaging devices by multi-level gain calibration and temperature correction.  

PubMed

Amorphous silicon (aSi:H) flat panel detectors are prevalent in radiotherapy for megavoltage imaging tasks. Any clinical and dosimetrical application requires a well-defined dose response of the system to achieve meaningful results. Due to radiation damages, panels deteriorate and the linearity of pixel response to dose as well as the stability with regard to changing operating temperatures get worse with time. Using a single level gain correction can lead to an error of about 23% when irradiating a flood field image with 100 MU min(-1) on an old detector. A multi-level gain (MLG) correction is introduced, emending the nonlinearities and subpanel-related artifacts caused by insufficient radiation hardness of amplifiers in the read-out electronics. With rising temperature, offset values typically increase (up to 300 gray values) while the response at higher dose values per frame remain constant for a majority of pixels. To account for temperature-related image artifacts, two additional temperature correction methods have been developed. MLG in combination with temperature corrections can re-establish the aSi:H image quality to the performance required by reliable medical verification tools. Furthermore, the life span and recalibration intervals of these costly devices can be prolonged decisively. PMID:23999060

Huber, S; Mooslechner, M; Mitterlechner, B; Weichenberger, H; Serpa, M; Sedlmayer, F; Deutschmann, H

2013-09-21

389

Civic Participation and Self-rated Health: A Cross-national Multi-level Analysis Using the World Value Survey  

PubMed Central

Objectives: Civic participation, that which directly influences important decisions in our personal lives, is considered necessary for developing a society. We hypothesized that civic participation might be related to self-rated health status. Methods: We constructed a multi-level analysis using data from the World Value Survey (44 countries, n=50 859). Results: People who participated in voting and voluntary social activities tended to report better subjective health than those who did not vote or participate in social activities, after controlling for socio-demographic factors at the individual level. A negative association with unconventional political activity and subjective health was found, but this effect disappeared in a subset analysis of only the 18 Organization for Economic Cooperation and Development (OECD) countries. Moreover, social participation and unconventional political participation had a statistically significant contextual association with subjective health status, but this relationship was not consistent throughout the analysis. In the analysis of the 44 countries, social participation was of borderline significance, while in the subset analysis of the OECD countries unconventional political participation was a stronger determinant of subjective health. The democratic index was a significant factor in determining self-rated health in both analyses, while public health expenditure was a significant factor in only the subset analysis. Conclusions: Despite the uncertainty of its mechanism, civic participation might be a significant determinant of the health status of a country. PMID:25652707

Kim, Saerom; Kim, Chang-yup; You, Myung Soon

2015-01-01

390

Multi-level slug tests in highly permeable formations: 1. Modification of the Springer-Gelhar (SG) model  

NASA Astrophysics Data System (ADS)

A multi-level slug test model and a method for the evaluation of vertical profiles of hydraulic conductivity in highly permeable formations are developed. A double-packer system is employed to estimate local hydraulic conductivity. Depending on the formation and double-packer system parameters, the water level recovery in the tested well can exhibit a monotonic or oscillatory response. To discern information on aquifer properties from artifacts introduced by the measurement system, the theory of flow in an aquifer and a double-packer system is developed. The mathematical model incorporates features of the Springer and Gelhar (1991) model and reduces to the Bouwer and Rice (1976) model in a special case. The model involves equations of momentum and mass conservation for the double-packer system with quasi-steady well-aquifer interaction equations. The method is uniformly applicable for both monotonic and oscillatory well responses and can produce profiles of hydraulic conductivity for the tested well. The criterion is given to determine the type of well response for given slug test conditions.

Zlotnik, Vitaly A.; McGuire, Virginia L.

1998-01-01

391

Theoretical investigation of the oceanic inverted barometer response  

NASA Technical Reports Server (NTRS)

Dynamic tidal theory is generalized in order to predict the oceanic response to atmospheric pressure variations. The oceans are found to exhibit distinct dynamic behavior when forced at periods less than one week; depending on the harmonic type of forcing, the amplitude of the response can differ by about 20 percent or more from the static response. Even at roughly two months the traditional 'inverted barometer' may not be sufficiently accurate for applications in which detection of long-term sea level trends or vertical crustal motion is the goal. For forcing at periods of order one year the oceanic response differs by at most a few percent from the static (not the inverted barometer) response; thus calculations of meteorological excitation of the annual and Chandler wobbles can employ the static approximation without reservation.

Dickman, S. R.

1988-01-01

392

A multi-level model for analyzing whole genome sequencing family data with longitudinal traits.  

PubMed

Compared with microarray-based genotyping, next-generation whole genome sequencing (WGS) studies have the strength to provide greater information for the identification of rare variants, which likely account for a significant portion of missing heritability of common human diseases. In WGS, family-based studies are important because they are likely enriched for rare disease variants that segregate with the disease in relatives. We propose a multilevel model to detect disease variants using family-based WGS data with longitudinal measures. This model incorporates the correlation structure from family pedigrees and that from repeated measures. The iterative generalized least squares algorithm was applied to estimation of parameters and test of associations. The model was applied to the data of Genetic Analysis Workshop 18 and compared with existing linear mixed-effect models. The multilevel model shows higher power at practical p-value levels and a better type I error control than linear mixed-effect model. Both multilevel and linear mixed-effect models, which use the longitudinal repeated information, have higher power than the methods that only use data collected at one time point. PMID:25519414

Chen, Taoye; Santawisook, Patchara; Wu, Zheyang

2014-01-01

393

Multi-Level Communication of Human Retinal Pigment Epithelial Cells via Tunneling Nanotubes  

PubMed Central

Background Tunneling nanotubes (TNTs) may offer a very specific and effective way of intercellular communication. Here we investigated TNTs in the human retinal pigment epithelial (RPE) cell line ARPE-19. Morphology of TNTs was examined by immunostaining and scanning electron microscopy. To determine the function of TNTs between cells, we studied the TNT-dependent intercellular communication at different levels including electrical and calcium signalling, small molecular diffusion as well as mitochondrial re-localization. Further, intercellular organelles transfer was assayed by FACS analysis. Methodology and Principal Findings Microscopy showed that cultured ARPE-19 cells are frequently connected by TNTs, which are not attached to the substratum. The TNTs were straight connections between cells, had a typical diameter of 50 to 300 nm and a length of up to 120 µm. We observed de novo formation of TNTs by diverging from migrating cells after a short time of interaction. Scanning electron microscopy confirmed characteristic features of TNTs. Fluorescence microscopy revealed that TNTs between ARPE-19 cells contain F-actin but no microtubules. Depolymerisation of F-actin, induced by addition of latrunculin-B, led to disappearance of TNTs. Importantly, these TNTs could function as channels for the diffusion of small molecules such as Lucifer Yellow, but not for large molecules like Dextran Red. Further, organelle exchange between cells via TNTs was observed by microscopy. Using Ca2+ imaging we show the intercellular transmission of calcium signals through TNTs. Mechanical stimulation led to membrane depolarisation, which expand through TNT connections between ARPE-19 cells. We further demonstrate that TNTs can mediate electrical coupling between distant cells. Immunolabelling for Cx43 showed that this gap junction protein is interposed at one end of 44% of TNTs between ARPE-19 cells. Conclusions and Significance Our observations indicate that human RPE cell line ARPE-19 cells communicate by tunneling nanotubes and can support different types of intercellular traffic. PMID:22457742

Wittig, Dierk; Wang, Xiang; Walter, Cindy; Gerdes, Hans-Hermann; Funk, Richard H. W.; Roehlecke, Cora

2012-01-01

394

From continental priorities to local conservation: a multi-level analysis for African tortoises.  

PubMed

Terrestrial tortoises are the most endangered group of vertebrates but they are still largely ignored for defining global conservation priorities. In this paper, we explored within a hierarchical framework the potential contribution of prioritization studies at the continental scale to the planning of local initiatives for the conservation of African tortoises at the regional level. First, we modeled the distribution of all the African tortoise species, we calculated three indicators of conservation priority (i.e., species richness, conservation value, and complementarity), and we carried out a gap analysis at continental scale. Second, we focused on the most important region for tortoise conservation and performed the same analyses at higher resolution. Finally, we compared the results from the two scales for understanding the degree to which they are complementary. Southern Africa emerged from the continental analysis as the most important region for tortoises. Within this area, the high-resolution analysis pointed out specific core sites for conservation. The relative degree of species protection was assessed similarly at the two different resolutions. Two species appeared particularly vulnerable at both scales. Priority indices calculated at high resolution were correlated to the values calculated for the corresponding cells at low resolution but the congruence was stronger for species richness. Our results suggest to integrate the calculation of conservation value and complementarity into a hierarchical framework driven by species richness. The advantages of large scale planning include its broad perspective on complementarity and the capability to identify regions with greatest conservation potential. In this light, continental analyses allow targeting fine scale studies toward regions with maximum priority. The regional analyses at fine scale allow planning conservation measure at a resolution similar to that required for the practical implementation, reducing the uncertainty associated with low resolution studies. PMID:24116208

Bombi, Pierluigi; D'Amen, Manuela; Luiselli, Luca

2013-01-01

395

Multi-level analysis of electronic health record adoption by health care professionals: A study protocol  

PubMed Central

Background The electronic health record (EHR) is an important application of information and communication technologies to the healthcare sector. EHR implementation is expected to produce benefits for patients, professionals, organisations, and the population as a whole. These benefits cannot be achieved without the adoption of EHR by healthcare professionals. Nevertheless, the influence of individual and organisational factors in determining EHR adoption is still unclear. This study aims to assess the unique contribution of individual and organisational factors on EHR adoption in healthcare settings, as well as possible interrelations between these factors. Methods A prospective study will be conducted. A stratified random sampling method will be used to select 50 healthcare organisations in the Quebec City Health Region (Canada). At the individual level, a sample of 15 to 30 health professionals will be chosen within each organisation depending on its size. A semi-structured questionnaire will be administered to two key informants in each organisation to collect organisational data. A composite adoption score of EHR adoption will be developed based on a Delphi process and will be used as the outcome variable. Twelve to eighteen months after the first contact, depending on the pace of EHR implementation, key informants and clinicians will be contacted once again to monitor the evolution of EHR adoption. A multilevel regression model will be applied to identify the organisational and individual determinants of EHR adoption in clinical settings. Alternative analytical models would be applied if necessary. Results The study will assess the contribution of organisational and individual factors, as well as their interactions, to the implementation of EHR in clinical settings. Conclusions These results will be very relevant for decision makers and managers who are facing the challenge of implementing EHR in the healthcare system. In addition, this research constitutes a major contribution to the field of knowledge transfer and implementation science. PMID:20416054

2010-01-01

396

Project Invert WP6 Case Studies Case studies  

E-print Network

Project Invert ­ WP6 Case Studies Case studies (update, June 2005) Final Report of Work Phase 6 Invert ­ WP6 Case Studies - The Invert project: Research project within the Altener Program Printed in Austria ­ June 2005 #12;Project Invert ­ WP6 Case Studies I CONTENT Page FIGURES

397

A multilevel inverter topology for inductively-coupled power transfer  

Microsoft Academic Search

This paper describes a multilevel inverter for delivering power to a set of frequency selectable induction heating targets for stimulating temperature sensitive polymer actuators. The proposed inverter topology overcomes the capacitor voltage balancing issue common to traditional multilevel inverters. This inverter is suitable for sustained real power transfer.

John I. Rodriguez; Steven B. Leeb

2003-01-01

398

Self-balancing of the clamping-capacitor-voltages in the multilevel capacitor-clamping-inverter under sub-harmonic PWM modulation  

Microsoft Academic Search

The paper explores the spontaneous coupled clamping-capacitor-current control loops and the resultant self-balancing property of the clamping-capacitor-voltages in the multilevel capacitor-clamping-inverter. The case of the three-level capacitor-clamping-inverter under sub-harmonic PWM modulation is dealt with first. The case of the multilevel capacitor-clamping-inverter (M>3) under sub-harmonic PWM modulation is then analyzed. Test results on a half-bridge three-level capacitor-clamping-inverter prototype under sub-harmonic PWM

Xiaoming Yuang; Herbert Stemmler; Ivo Barbi

2001-01-01

399

An Analysis of Series Inverter Circuits  

Microsoft Academic Search

This paper presents an unified approach to obtain the steady-state solutions for some inverter circuits. It is also proved incidentally that these systems actually exhibit a stable limit cycle phenomena.

R. Kasturi

1975-01-01

400

Integrated Inverter For Driving Multiple Electric Machines  

DOEpatents

An electric machine drive (50) has a plurality of inverters (50a, 50b) for controlling respective electric machines (57, 62), which may include a three-phase main traction machine (57) and two-phase accessory machines (62) in a hybrid or electric vehicle. The drive (50) has a common control section (53, 54) for controlling the plurality of inverters (50a, 50b) with only one microelectronic processor (54) for controlling the plurality of inverters (50a, 50b), only one gate driver circuit (53) for controlling conduction of semiconductor switches (S1-S10) in the plurality of inverters (50a, 50b), and also includes a common dc bus (70), a common dc bus filtering capacitor (C1) and a common dc bus voltage sensor (67). The electric machines (57, 62) may be synchronous machines, induction machines, or PM machines and may be operated in a motoring mode or a generating mode.

Su, Gui-Jia [Knoxville, TN; Hsu, John S [Oak Ridge, TN

2006-04-04

401

Removing Barriers to Utility Interconnected Photovoltaic Inverters  

SciTech Connect

The Million Solar Roofs Initiative has motivated a renewed interest in the development of utility interconnected photovoltaic (UIPV) inverters. Government-sponsored programs (PVMaT, PVBONUS) and competition among utility interconnected inverter manufacturers have stimulated innovations and improved the performance of existing technologies. With this resurgence, Sandia National Laboratories (SNL) has developed a program to assist industry initiatives to overcome barriers to UIPV inverters. In accordance with newly adopted IEEE 929-2000, the utility interconnected PV inverters are required to cease energizing the utility grid when either a significant disturbance occurs or the utility experiences an interruption in service. Compliance with IEEE 929-2000 is being widely adopted by utilities as a minimum requirement for utility interconnection. This report summarizes work done at the SNL balance-of-systems laboratory to support the development of IEEE 929-2000 and to assist manufacturers in meeting its requirements.

Gonzalez, S.; Bonn, R.H.; Ginn, J.W.

2000-10-03

402

Inverted (Reverse) Takotsubo Cardiomyopathy following Cerebellar Hemorrhage  

PubMed Central

Background. First described in 2005, inverted takotsubo is one of the four stress-induced cardiomyopathy patterns. It is rarely associated with subarachnoid hemorrhage but was not previously reported after intraparenchymal bleeding. Purpose. We reported a symptomatic case of inverted takotsubo pattern following a cerebellar hemorrhage. Case Report. A 26-year-old woman presented to the emergency department with sudden headache and hemorrhage of the posterior fossa was diagnosed, probably caused by a vascular malformation. Several hours later, she developed acute pulmonary edema due to acute heart failure. Echocardiography showed left ventricular dysfunction with hypokinetic basal segments and hyperkinetic apex corresponding to inverted takotsubo. Outcome was spontaneously favorable within a few days. Conclusion. Inverted takotsubo pattern is a stress-induced cardiomyopathy that could be encountered in patients with subarachnoid hemorrhage and is generally of good prognosis. We described the first case following a cerebellar hematoma. PMID:24826313

Piérard, Sophie; Vinetti, Marco

2014-01-01

403

Schneiderian Inverted Papilloma: Report of a Case  

PubMed Central

A case of Schneiderian inverted papilloma is presented. Etiology, gross and microscopic pathology, and clinical course are discussed along with a plan of treatment. ImagesFigure 1Figure 2Figure 3Figure 4 PMID:722828

Jones, Beulah D.

1978-01-01

404

The Research Process in a Multi-Level Mixed-Methods Case Study: International Organization Headquarters and Field Employee Perspectives of a Program in Southern Sudan  

ERIC Educational Resources Information Center

This article provides an overview of the methods and data-collection process for a multi-level mixed-methods case study. Data for the study were gathered through phone interviews and electronic surveys from individuals working on the same educational program in Southern Sudan, though some were supporting the program from outside the country. The…

Eschenbacher, Heidi

2012-01-01

405

The use of multi?level modelling in risk research. A secondary analysis of a study of public perceptions of genetically modified food  

Microsoft Academic Search

Many studies have examined the relationship between various individual variables and people's perceptions of genetically modified (GM) food. A problem with this type of research is that contextual factors are completely ignored. This article explores the use of multi?level modelling in the field of risk research, by re?analysing a recent British study of public perceptions of GM food. As the

Wouter Poortinga

2005-01-01

406

To appear in Proceedings of the Sixteenth National Conference on Artificial Intelligence (AAAI99) Learning Dictionaries for Information Extraction by MultiLevel  

E-print Network

bootstrapping technique that learns extraction patterns from the seed words and then exploits the learned ex) Learning Dictionaries for Information Extraction by Multi­Level Bootstrapping Ellen Riloff Department extraction systems usually require two dictionaries: a semantic lexicon and a dictionary of ex­ traction

Olsson, Fredrik

407

Self-Complementary Inverted-FL Antenna Using Electromagnetic Coupling Feed for Mobile Phone  

NASA Astrophysics Data System (ADS)

In this paper, the author proposes an electromagnetic coupling fed inverted-FL antenna design. The inverted-FL antenna with a self-complementary structure has been reported as a way to achieve a constant impedance of 188 ohms without the need for a matching load, since the axially symmetric self-complementary antenna has constant impedance, even though it has a finite structure. This design has been realized by integrating an inverted-F antenna with a self-complementary structure for achieving a broadband characteristic and an inverted-L element for operation on a frequency lower than the minimum frequency of the antenna. The proposed antenna realizes a broadband characteristic without attaching the matching load and the impedance transformer to match 50 ohms. The impedance transformer necessary for the inverted-FL antenna with a self-complementary structure is removed by using an electromagnetic coupling feed structure. This antenna, which has a volume of 10×10×45mm3, obtained broadband and multi-band characteristics covering the GSM850/GSM900/DCS/PCS/UMTS2100/UMTS2600 bands and the 2.5G/3.5G bands for Mobile-WiMAX in simulation and measurement.

Takemura, Nobuyasu

408

Experiment on Changeover Voltage Surge Suppression in Gradationally Controlled Voltage Inverter Model without Transformers for Maglev System  

NASA Astrophysics Data System (ADS)

The converter in the Yamanashi Maglev system, which has PWM inverters connected in series via output transformers, has some points to be improved. One is that the transformers are costly and require a large space the other is that a large filter is required to suppress the zero sequence current. In this paper, we propose a gradationally controlled voltage inverter without transformers for the Maglev system. It has one set of three-phase, 3-level inverters and three sets of 7-level, single-phase inverters, which are connected in series. It can output 21 gradational voltage levels and can suppress the zero-sequence voltage which causes the zero sequence current. We at first explain the principle, features, and expected problems of the inverter system. Then we demonstrate the generation of a gradationally controlled voltage with an experimental inverter model. Finally, we explain how to suppress the changeover voltage surge which occurs at the point when changing the level. We conclude that the gradationally controlled voltage inverter without transformers will be useful for the Maglev system.

Kishida, Yukimori; Iwata, Akihiko; Yonehata, Yuzuru; Yoshiyasu, Hajimu; Higashi, Kotaro; Morishima, Naoki; Enomoto, Jun; Kitano, Jun-Ichi; Ikeda, Haruo

409

Base drive for paralleled inverter systems  

NASA Technical Reports Server (NTRS)

In a paralleled inverter system, a positive feedback current derived from the total current from all of the modules of the inverter system is applied to the base drive of each of the power transistors of all modules, thereby to provide all modules protection against open or short circuit faults occurring in any of the modules, and force equal current sharing among the modules during turn on of the power transistors.

Nagano, S. (inventor)

1980-01-01

410

Safety and Efficacy of Bioabsorbable Cervical Spacers and Low-Dose rhBMP-2 in Multi-Level ACDF  

PubMed Central

Introduction Many options for interbody spacer and graft biologic exist for multilevel anterior cervical discectomy and fusion (ACDF). The objective of this study is to evaluate the safety and efficacy of a bioabsorbable cervical spacer (BCS) (Cornerstone HSR, Medtronic Sofamor Danek) filled with low-dose rhBMP-2 (INFUSE, Medtronic Sofamor Danek) in multilevel ACDF. Methods 72 consecutive patients treated with a multi-level ACDF using BCS and rhBMP-2 (dosage between 0.5 to 0.7 mg per level) at a single institution were followed in an IRB-approved, prospective registry. A total of 187 levels were treated (mean = 2.6), with 37 (51%) patients undergoing a 2-level procedure and 35 (49%) undergoing a 3- or 4-level procedure. Statistical analysis included frequency and ANOVA tests. Significance was accepted for p < 0.001. Results Average follow-up was 13.8 months. Mean patient age was 55.3 years, 70.8% were female, and 16.7% had undergone a previous cervical procedure. 29 (40%) patients had cervical spondylitic myelopathy, 27 (38%) had radiculopathy, 15 (21%) had a combination of both, and 1 (1%) patient had a previous nonunion. A total of 187 levels were treated with an ACDF, with 37 (51%) 2-level, 27 (38%) 3-level, and 8 (11%) 4-level cases. Average OR time, EBL, and LOS were 144 minutes, 49 mL, and 1.1 days, respectively. Major complications occurred in 5 (7%) patients: 2 returns to OR (1 nonunion, 1 seroma), 1 recurrent laryngeal nerve injury, and 2 hospital readmissions for excessive pre-vertebral swelling/dysphagia treated with steroids and observation. Minor complications occurred in 3 (4%) patients: 2 exacerbations of pre-existing medical conditions (1 atrial fibrillation, 1 COPD), and 1 hospital readmission for nausea/ headache due to narcotics. At last follow-up, NDI improved 43% from 43.6% to 25.0%. VAS neck pain improved 60% from 5.5 to 2.2 and VAS arm pain improved 52% from 5.8 to 2.6. SF-36 PCS improved 24% from 37.5 to 46.3 and MCS improved 18% from 43.2 to 50.9. All clinical improvements were statistically significant (p < 0.001). Patient satisfaction was high, with 97% of patients reported being satisfied with their surgical outcome, and 90% would undergo the procedure again. Conclusion Patients in this series experienced significant clinical improvements, low complication rates, and high patient satisfaction. Symptomatic pseudoarthrosis was rare. BCS filled with low-dose rhBMP-2 appears to be a safe and effective option in multilevel ACDF. Further investigation is warranted.

Khajavi, Kaveh; Shen, Alessandria

2014-01-01

411

Environmental Risk Score as a New Tool to Examine Multi-Pollutants in Epidemiologic Research: An Example from the NHANES Study Using Serum Lipid Levels  

PubMed Central

Objective A growing body of evidence suggests that environmental pollutants, such as heavy metals, persistent organic pollutants and plasticizers play an important role in the development of chronic diseases. Most epidemiologic studies have examined environmental pollutants individually, but in real life, we are exposed to multi-pollutants and pollution mixtures, not single pollutants. Although multi-pollutant approaches have been recognized recently, challenges exist such as how to estimate the risk of adverse health responses from multi-pollutants. We propose an “Environmental Risk Score (ERS)” as a new simple tool to examine the risk of exposure to multi-pollutants in epidemiologic research. Methods and Results We examined 134 environmental pollutants in relation to serum lipids (total cholesterol, high-density lipoprotein cholesterol (HDL), low-density lipoprotein cholesterol (LDL) and triglycerides) using data from the National Health and Nutrition Examination Survey between 1999 and 2006. Using a two-stage approach, stage-1 for discovery (n?=?10818) and stage-2 for validation (n?=?4615), we identified 13 associated pollutants for total cholesterol, 9 for HDL, 5 for LDL and 27 for triglycerides with adjustment for sociodemographic factors, body mass index and serum nutrient levels. Using the regression coefficients (weights) from joint analyses of the combined data and exposure concentrations, ERS were computed as a weighted sum of the pollutant levels. We computed ERS for multiple lipid outcomes examined individually (single-phenotype approach) or together (multi-phenotype approach). Although the contributions of ERS to overall risk predictions for lipid outcomes were modest, we found relatively stronger associations between ERS and lipid outcomes than with individual pollutants. The magnitudes of the observed associations for ERS were comparable to or stronger than those for socio-demographic factors or BMI. Conclusions This study suggests ERS is a promising tool for characterizing disease risk from multi-pollutant exposures. This new approach supports the need for moving from a single-pollutant to a multi-pollutant framework. PMID:24901996

Park, Sung Kyun; Tao, Yebin; Meeker, John D.; Harlow, Siobán D.; Mukherjee, Bhramar

2014-01-01

412

Probing the interactions between carboxylated multi-walled carbon nanotubes and copper-zinc superoxide dismutase at a molecular level.  

PubMed

In order to evaluate the toxicity of multi-walled carbon nanotubes (MWCNTs-COOH) at a molecular level, the effect of MWCNTs-COOH on antioxidant enzyme copper-zinc superoxide dismutase (Cu/ZnSOD) was investigated using fluorescence spectroscopy, UV/vis absorption spectroscopy, circular dichroism (CD) spectroscopy and isothermal titration calorimetry (ITC). By deducting the inner filter effect (IFE), the fluorescence emission spectra and synchronous fluorescence spectra indicated that there were interactions between MWCNTs-COOH and Cu/ZnSOD. Moreover, the microenvironment of the amino acid residues in the enzyme was changed slightly. The UV/vis absorption and CD spectroscopic results showed appreciable conformational changes in Cu/ZnSOD. However, the results of a Cu/ZnSOD activity determination did not show any significant difference. In other words, MWCNTs-COOH has no significant effect on enzyme activity. The ITC results showed that the binding of MWCNTs-COOH to Cu/ZnSOD was a weak endothermic process, indicating that the predominant force of the binding was hydrophobic interaction. Moreover, it was essential to consider the IFE in fluorescence assays, which might affect the accuracy and precision of the results. The above results are helpful in evaluating the oxidative stress induced by MWCNTs-COOH in vivo. Copyright © 2014 John Wiley & Sons, Ltd. PMID:25351393

Guan, Jin; Liu, Guiliang; Cai, Kai; Gao, Canzhu; Liu, Rutao

2014-10-29

413

A taxonomy and comparison of parallel block multi-level preconditioners for the incompressible Navier-Stokes equations.  

SciTech Connect

In recent years, considerable effort has been placed on developing efficient and robust solution algorithms for the incompressible Navier-Stokes equations based on preconditioned Krylov methods. These include physics-based methods, such as SIMPLE, and purely algebraic preconditioners based on the approximation of the Schur complement. All these techniques can be represented as approximate block factorization (ABF) type preconditioners. The goal is to decompose the application of the preconditioner into simplified sub-systems in which scalable multi-level type solvers can be applied. In this paper we develop a taxonomy of these ideas based on an adaptation of a generalized approximate factorization of the Navier-Stokes system first presented in [25]. This taxonomy illuminates the similarities and differences among these preconditioners and the central role played by efficient approximation of certain Schur complement operators. We then present a parallel computational study that examines the performance of these methods and compares them to an additive Schwarz domain decomposition (DD) algorithm. Results are presented for two and three-dimensional steady state problems for enclosed domains and inflow/outflow systems on both structured and unstructured meshes. The numerical experiments are performed using MPSalsa, a stabilized finite element code.

Shadid, John Nicolas (Sandia National Laboratories, Albuquerque, NM); Elman, Howard (University of Maryland, College Park, MD); Shuttleworth, Robert R. (University of Maryland, College Park, MD); Howle, Victoria E.; Tuminaro, Raymond Stephen

2007-04-01

414

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

PubMed

A multi-residue HPLC-ESI-MS/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 target concentration. The method was in-house validated and meets all criteria of European legislation (2002/657/EC). The precision of the method was determined under repeatability and within-laboratory reproducibility conditions; RSD(r) and RSD(R) were below the maximum permitted values for every tested concentration. The specificity was checked by analysing representative blank samples and blank samples fortified with potentially interfering substances (benzimidazoles, corticosteroides, triphenylmethane dyes, quinolones, nitrofurans, nitroimidazoles, phenicols); no interference were found. Concerning quantification, a quadratic regression model was fitted to every calibration curve with a regression coefficient r2 above 0.99 on each data set. Finally, the expanded uncertainty U was calculated with data obtained within the laboratory while applying the method during validation and in routine tests. PMID:20198524

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

2010-06-01

415

Multi-level three-dimensional Mg-Al layered double hydroxide hierarchical microstructures with enhanced basic catalytic property.  

PubMed

Novel three-dimensional (3D) rosette-like carbonate-type Mg-Al layered double hydroxide (MgAl-LDH) hierarchical microstructures were fabricated successfully by a surfactant-assisted coprecipitation method in the presence of hexamethylenetetramine as precipitant, and the morphology-dependent basic catalytic property was exploited. The morphologies of MgAl-LDH aggregates were diversified depending on the synthesis parameters including the type of precipitant, concentration of sodium stearate surfactant, and hydrothermal aging time. Specifically, the morphology of MgAl-LDH particles could change progressively from platelet-like aggregates to rosette-like microspheres with the increasing concentration of sodium stearate. A possible formation mechanism for special 3D flower-like MgAl-LDH microstructures was proposed based on the synergistic effect of precipitant with surfactant. Moreover, the resulting activated rosette-like MgAl-LDH, which was prepared through calcination-rehydration process, showed a higher catalytic activity in the transesterification of tributyrin with methanol, compared with that derived from the conventional platelet-like MgAl-LDH precursor, which was attributed to its higher specific basicity originating from multi-level hierarchical superstructure offering an advantage in contact with more exposed base sites. PMID:25036381

Yu, Jiaying; Fan, Guoli; Yang, Yang; Li, Feng

2014-10-15

416

A wafer-level multi-chip module process with thick photosensitive benzocyclobutene as the dielectric for microwave application  

NASA Astrophysics Data System (ADS)

A wafer-level microwave multi-chip module (MMCM) packaging process is presented. Thick photosensitive-benzocyclobutene (photo-BCB) polymer (about 25 µm/layer) is used as the dielectric for its simplified process and the capability of obtaining desirable electrical, chemical and mechanical properties at high frequencies. The MMCM packaging structure contains a monolithic microwave integrated circuit (MMIC) chip embedded in a lossy-silicon wafer, a microwave band-pass filter (BPF) and two layers of BCB/Au interconnection. Key processes of fabrication are described in detail. The non-uniformity of BCB film and the sidewall angle of the via-holes for inter-layer connection are tested. Via-chains prepared by metal/BCB multilayer structures are tested through the Kelvin test structure to investigate the resistances of inter-layer connection. The average value is measured to be 73.5 m?. The electrical characteristic of this structure is obtained by a microwave transmission performance test from 15 to 30 GHz. The measurement results show good consistency between the bare MMIC die and the packaged die in the test frequency band. The gain of the MMIC chip after packaging is better than 18 dB within the designed operating frequency range (from 23 to 25 GHz). When the packaged MMIC chip is connected to a BPF, the maximum gain is still measured to reach 11.95 dB at 23.8 GHz.

Tang, Jiajie; Sun, Xiaowei; Luo, Le

2011-06-01

417

ENSO to multi-decadal time scale changes in East Australian Current transports and Fort Denison sea level: Oceanic Rossby waves as the connecting mechanism  

NASA Astrophysics Data System (ADS)

The connection between East Australian Current (EAC) transport variability and Australia's east coast sea level has received little treatment in the literature. This is due in part to the complex interacting physical processes operating in the coastal zone combined with the sparsity of observations available to improve our understanding of these possible connections. This study demonstrates a statistically significant (at the >90% level) relationship between interannual to decadal time scale variations in observed estimates of the EAC transport changes and east coast sea level measured at the high-quality, long record Fort Denison tide-gauge in Sydney Harbour, Australia (33°51'18?S, 151°13'32?E). We further demonstrate, using a linear reduced-gravity ocean model, that ENSO to decadal time-scale variations and the ocean-adjusted multi-decadal trend (approx. 1 cm/decade) in observed sea level at Fort Denison are strongly connected to modulations of EAC transports by incoming westward propagating oceanic Rossby waves. We show that EAC transport and Fort Denison sea level vary in a manner expected from both Tasman Sea generated Rossby waves, which account for the interannual and multi-annual variability, and remotely forced (from east of New Zealand) Rossby wave connections through the mid-latitudes, accounting for the ocean-adjusted multi-decadal trend observed at the New South Wales coast - with the regional-Tasman Sea forcing explaining the greatest overall proportion of EAC transport and sea-level variances.

Holbrook, Neil J.; Goodwin, Ian D.; McGregor, Shayne; Molina, Ernesto; Power, Scott B.

2011-03-01

418

DC-AC Cascaded H-Bridge Multilevel Boost Inverter With No Inductors for Electric/Hybrid Electric Vehicle Applications  

SciTech Connect

This paper presents a cascaded H-bridge multilevel boost inverter for electric vehicle (EV) and hybrid EV (HEV) applications implemented without the use of inductors. Currently available power inverter systems for HEVs use a dc-dc boost converter to boost the battery voltage for a traditional three-phase inverter. The present HEV traction drive inverters have low power density, are expensive, and have low efficiency because they need a bulky inductor. A cascaded H-bridge multilevel boost inverter design for EV and HEV applications implemented without the use of inductors is proposed in this paper. Traditionally, each H-bridge needs a dc power supply. The proposed design uses a standard three-leg inverter (one leg for each phase) and an H-bridge in series with each inverter leg which uses a capacitor as the dc power source. A fundamental switching scheme is used to do modulation control and to produce a five-level phase voltage. Experiments show that the proposed dc-ac cascaded H-bridge multilevel boost inverter can output a boosted ac voltage without the use of inductors.

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

2009-01-01

419

The clubfoot assessment protocol (CAP); description and reliability of a structured multi-level instrument for follow-up  

PubMed Central

Background In most clubfoot studies, the outcome instruments used are designed to evaluate classification or long-term cross-sectional results. Variables deal mainly with factors on body function/structure level. Wide scorings intervals and total sum scores increase the risk that important changes and information are not detected. Studies of the reliability, validity and responsiveness of these instruments are sparse. The lack of an instrument for longitudinal follow-up led the investigators to develop the Clubfoot Assessment Protocol (CAP). The aim of this article is to introduce and describe the CAP and evaluate the items inter- and intra reliability in relation to patient age. Methods The CAP was created from 22 items divided between body function/structure (three subgroups) and activity (one subgroup) levels according to the International Classification of Function, Disability and Health (ICF). The focus is on item and subgroup development. Two experienced examiners assessed 69 clubfeet in 48 children who had a median age of 2.1 years (range, 0 to 6.7 years). Both treated and untreated feet with different grades of severity were included. Three age groups were constructed for studying the influence of age on reliability. The intra- rater study included 32 feet in 20 children who had a median age of 2.5 years (range, 4 months to 6.8 years). The Unweighted Kappa statistics, percentage observer agreement, and amount of categories defined how reliability was to be interpreted. Results The inter-rater reliability was assessed as moderate to good for all but one item. Eighteen items had kappa values > 0.40. Three items varied from 0.35 to 0.38. The mean percentage observed agreement was 82% (range, 62 to 95%). Different age groups showed sufficient agreement. Intra- rater; all items had kappa values > 0.40 [range, 0.54 to 1.00] and a mean percentage agreement of 89.5%. Categories varied from 3 to 5. Conclusion The CAP contains more detailed information than previous protocols. It is a multi-dimensional observer administered standardized measurement instrument with the focus on item and subgroup level. It can be used with sufficient reliability, independent of age, during the first seven years of childhood by examiners with good clinical experience. A few items showed low reliability, partly dependent on the child's age and /or varying professional backgrounds between the examiners. These items should be interpreted with caution, until further studies have confirmed the validity and sensitivity of the instrument. PMID:16022741

Andriesse, Hanneke; Hägglund, Gunnar; Jarnlo, Gun-Britt

2005-01-01

420

Towards people-centred health systems: a multi-level framework for analysing primary health care governance in low- and middle-income countries  

PubMed Central

Although there is evidence that non-government health system actors can individually or collectively develop practical strategies to address primary health care (PHC) challenges in the community, existing frameworks for analysing health system governance largely focus on the role of governments, and do not sufficiently account for the broad range of contribution to PHC governance. This is important because of the tendency for weak governments in low- and middle-income countries (LMICs). We present a multi-level governance framework for use as a thinking guide in analysing PHC governance in LMICs. This framework has previously been used to analyse the governance of common-pool resources such as community fisheries and irrigation systems. We apply the framework to PHC because, like common-pool resources, PHC facilities in LMICs tend to be commonly owned by the community such that individual and collective action is often required to avoid the ‘tragedy of the commons’—destruction and degradation of the resource resulting from lack of concern for its continuous supply. In the multi-level framework, PHC governance is conceptualized at three levels, depending on who influences the supply and demand of PHC services in a community and how: operational governance (individuals and providers within the local health market), collective governance (community coalitions) and constitutional governance (governments at different levels and other distant but influential actors). Using the example of PHC governance in Nigeria, we illustrate how the multi-level governance framework offers a people-centred lens on the governance of PHC in LMICs, with a focus on relations among health system actors within and between levels of governance. We demonstrate the potential impact of health system actors functioning at different levels of governance on PHC delivery, and how governance failure at one level can be assuaged by governance at another level. PMID:25274638

Abimbola, Seye; Negin, Joel; Jan, Stephen; Martiniuk, Alexandra

2014-01-01

421

Characterization of Post-traumatic Stress Disorder Using Resting-State fMRI with a Multi-level Parametric Classification Approach.  

PubMed

Functional neuroimaging studies have found intra-regional activity and inter-regional connectivity alterations in patients with post-traumatic stress disorder (PTSD). However, the results of these studies are based on group-level statistics and therefore it is unclear whether PTSD can be discriminated at single-subject level, for instance using the machine learning approach. Here, we proposed a novel framework to identify PTSD using multi-level measures derived from resting-state functional MRI (fMRI). Specifically, three levels of measures were extracted as classification features: (1) regional amplitude of low-frequency fluctuations (univariate feature), which represents local spontaneous synchronous neural activity; (2) temporal functional connectivity (bivariate feature), which represents the extent of similarity of local activity between two regions, and (3) spatial functional connectivity (multivariate feature), which represents the extent of similarity of temporal correlation maps between two regions. Our method was evaluated on 20 PTSD patients and 20 demographically matched healthy controls. The experimental results showed that the features of each level could successfully discriminate PTSD patients from healthy controls. Furthermore, the combination of multi-level features using multi-kernel learning can further improve the classification performance. Specifically, the classification accuracy obtained by the proposed framework was 92.5 %, which was an increase of at least 5 and 17.5 % from the two-level and single-level feature based methods, respectively. Particularly, the limbic structure and prefrontal cortex provided the most discriminant features for classification, consistent with results reported in previous studies. Together, this study demonstrated for the first time that patients with PTSD can be identified at the individual level using resting-state fMRI data. The promising classification results indicated that this method may provide a complementary approach for improving the clinical diagnosis of PTSD. PMID:25078561

Liu, Feng; Xie, Bing; Wang, Yifeng; Guo, Wenbin; Fouche, Jean-Paul; Long, Zhiliang; Wang, Wenqin; Chen, Heng; Li, Meiling; Duan, Xujun; Zhang, Jiang; Qiu, Mingguo; Chen, Huafu

2015-03-01

422

Addressable inverter matrix for process and device characterization  

NASA Technical Reports Server (NTRS)

The addressable inverter matrix consists of 222 inverters each accessible with the aid of a shift register. The structure has proven useful in characterizing the variability of inverter transfer curves and in diagnosing processing faults. For good 3-micron CMOS bulk inverters investigated in this study, the percent standard deviation of the inverter threshold voltage was less than one percent and the inverter gain (the slope of the inverter transfer curve at the inverter threshold voltage) was less than 3 percent. The average noise margin for the inverters was near 2 volts for a power supply voltage of 5 volts. The specific faults studied included undersize pull-down transistor widths and various open contacts in the matrix.

Buehler, M. G.; Sayah, H. R.

1985-01-01

423

Addressable inverter matrix for process and device characterization  

NASA Technical Reports Server (NTRS)

The addressable inverter matrix consists of 222 inverters each accessible with the aid of a shift register. The structure has proven useful in characterizing the variability of inverter transfer curves and in diagnosing processing faults. For good 3-micron CMOS bulk inverters investigated, the percent standard deviation of the inverter threshold voltage was less than one percent and the inverter gain (the slope of the inverter transfer curve at the inverter threshold vltage) was less than 3 percent. The average noise margin for the inverters was near 2 volts for a power supply voltage of 5 volts. The specific faults studied included undersize pull-down transistor widths and various open contacts in the matrix.

Buehler, M. G.; Sayah, H. R.

1985-01-01

424

Trade liberalization and tuberculosis incidence: a longitudinal multi-level analysis in 22 high burden countries between 1990 and 2010  

PubMed Central

Background Trade liberalization is promoted by the World Trade Organization (WTO) through a complex architecture of binding trade agreements. This type of trade, however, has the potential to modify the upstream and proximate determinants of tuberculosis (TB) infection. We aimed to analyse the association between trade liberalization and TB incidence in 22 high-burden TB countries between 1990 and 2010. Methods and findings A longitudinal multi-level linear regression analysis was performed using five different measures of trade liberalization as exposure [WTO membership, duration of membership, trade as % of gross domestic product, and components of both the Economic Freedom of the World Index (EFI4) and the KOF Index of Globalization (KOF1)]. We adjusted for a wide range of factors, including differences in human development index (HDI), income inequality, debts, polity patterns, conflict, overcrowding, population stage transition, health system financing, case detection rates and HIV prevalence. None of the five trade indicators was significantly associated with TB incidence in the crude analysis. Any positive effect of EFI4 on (Log-) TB incidence over time was confounded by differences in socio-economic development (HDI), HIV prevalence and health financing indicators. The adjusted TB incidence rate ratio of WTO member countries was significantly higher [RR: 1.60; 95% confidence interval (CI): 1.12–2.29] when compared with non-member countries. Conclusion We found no association between specific aggregate indicators of trade liberalization and TB incidence. Our analyses provide evidence of a significant association between WTO membership and higher TB incidence, which suggests a possible conflict between the architecture of WTO agreements and TB-related Millennium Development Goals. Further research is needed, particularly on the relation between the aggregate trade indices used in this study and the hypothesized mediators and also on sector-specific indices, specific trade agreements and other (non-TB) health outcomes. PMID:23595571

Bozorgmehr, Kayvan; San Sebastian, Miguel

2014-01-01

425

Multi-Level Ewald: A hybrid multigrid / Fast Fourier Transform approach to the electrostatic particle—mesh problem  

PubMed Central

We present a new method for decomposing the one convolution required by standard Particle-Particle Particle-Mesh (P3M) electrostatic methods into a series of convolutions over slab-shaped subregions of the original simulation cell. Most of the convolutions derive data from separate regions of the cell and can thus be computed independently via FFTs, in some cases with a small amount of zero padding so that the results of these sub-problems may be reunited with minimal error. A single convolution over the entire cell is also performed, but using a much coarser mesh than the original problem would have required. This “Multi-Level Ewald” (MLE) method therefore requires moderately more FFT work plus the tasks of interpolating between different sizes of mesh and accumulating the results from neighboring sub-problems, but we show that the added expense can be less than 10% of the total simulation cost. We implement MLE as an approximation to the Smooth Particle Mesh Ewald (SPME) style of P3M, and identify a number of tunable parameters in MLE. With reasonable settings pertaining to the degree of overlap between the various sub-problems and the accuracy of interpolation between meshes, the errors obtained by MLE can be smaller than those obtained in molecular simulations with typical SPME settings. We compare simulations of a box of water molecules performed with MLE and SPME, and show that the energy conservation, structural, and dynamical properties of the system are more affected by the accuracy of the SPME calculation itself than by the additional MLE approximation. We anticipate that the MLE method’s ability to break a single convolution into many independent sub-problems will be useful for extending the parallel scaling of molecular simulations. PMID:22039358

Cerutti, David S.; Case, David A.

2010-01-01

426

Vocal communication in a complex multi-level society: constrained acoustic structure and flexible call usage in Guinea baboons  

PubMed Central

Background To understand the evolution of acoustic communication in animals, it is important to distinguish between the structure and the usage of vocal signals, since both aspects are subject to different constraints. In terrestrial mammals, the structure of calls is largely innate, while individuals have a greater ability to actively initiate or withhold calls. In closely related taxa, one would therefore predict a higher flexibility in call usage compared to call structure. In the present study, we investigated the vocal repertoire of free living Guinea baboons (Papio papio) and examined the structure and usage of the animals’ vocal signals. Guinea baboons live in a complex multi-level social organization and exhibit a largely tolerant and affiliative social style, contrary to most other baboon taxa. To classify the vocal repertoire of male and female Guinea baboons, cluster analyses were used and focal observations were conducted to assess the usage of vocal signals in the particular contexts. Results In general, the vocal repertoire of Guinea baboons largely corresponded to the vocal repertoire other baboon taxa. The usage of calls, however, differed considerably from other baboon taxa and corresponded with the specific characteristics of the Guinea baboons’ social behaviour. While Guinea baboons showed a diminished usage of contest and display vocalizations (a common pattern observed in chacma baboons), they frequently used vocal signals during affiliative and greeting interactions. Conclusions Our study shows that the call structure of primates is largely unaffected by the species’ social system (including grouping patterns and social interactions), while the usage of calls can be more flexibly adjusted, reflecting the quality of social interactions of the individuals. Our results support the view that the primary function of social signals is to regulate social interactions, and therefore the degree of competition and cooperation may be more important to explain variation in call usage than grouping patterns or group size. PMID:24059742

2013-01-01

427

Multi-level modeling of light-induced stomatal opening offers new insights into its regulation by drought.  

PubMed

Plant guard cells gate CO2 uptake and transpirational water loss through stomatal pores. As a result of decades of experimental investigation, there is an abundance of information on the involvement of specific proteins and secondary messengers in the regulation of stomatal movements and on the pairwise relationships between guard cell components. We constructed a multi-level dynamic model of guard cell signal transduction during light-induced stomatal opening and of the effect of the plant hormone abscisic acid (ABA) on this process. The model integrates into a coherent network the direct and indirect biological evidence regarding the regulation of seventy components implicated in stomatal opening. Analysis of this signal transduction network identified robust cross-talk between blue light and ABA, in which [Ca2+]c plays a key role, and indicated an absence of cross-talk between red light and ABA. The dynamic model captured more than 10(31) distinct states for the system and yielded outcomes that were in qualitative agreement with a wide variety of previous experimental results. We obtained novel model predictions by simulating single component knockout phenotypes. We found that under white light or blue light, over 60%, and under red light, over 90% of all simulated knockouts had similar opening responses as wild type, showing that the system is robust against single node loss. The model revealed an open question concerning the effect of ABA on red light-induced stomatal opening. We experimentally showed that ABA is able to inhibit red light-induced stomatal opening, and our model offers possible hypotheses for the underlying mechanism, which point to potential future experiments. Our modelling methodology combines simplicity and flexibility with dynamic richness, making it well suited for a wide class of biological regulatory systems. PMID:25393147

Sun, Zhongyao; Jin, Xiaofen; Albert, Réka; Assmann, Sarah M

2014-11-01

428

A multi-level approach of evaluating crew resource management training: a laboratory-based study examining communication skills as a function of team congruence.  

PubMed

The article proposes a multi-level approach for evaluating communication skills training (CST) as an important element of crew resource management (CRM) training. Within this methodological framework, the present work examined the effectiveness of CST in matching or mismatching team compositions with regard to hierarchical status and competence. There is little experimental research that evaluated the effectiveness of CRM training at multiple levels (i.e. reaction, learning, behaviour) and in teams composed of members of different status and competence. An experiment with a two (CST: with vs. without) by two (competence/hierarchical status: congruent vs. incongruent) design was carried out. A total of 64 participants were trained for 2.5 h on a simulated process control environment, with the experimental group being given 45 min of training on receptiveness and influencing skills. Prior to the 1-h experimental session, participants were assigned to two-person teams. The results showed overall support for the use of such a multi-level approach of training evaluation. Stronger positive effects of CST were found for subjective measures than for objective performance measures. STATEMENT OF RELEVANCE: This work provides some guidance for the use of a multi-level evaluation of CRM training. It also emphasises the need to collect objective performance data for training evaluation in addition to subjective measures with a view to gain a more accurate picture of the benefits of such training approaches. PMID:20967655

Sauer, J; Darioly, A; Mast, M Schmid; Schmid, P C; Bischof, N

2010-11-01

429

Calf-Level Factors Associated with Bovine Neonatal Pancytopenia – A Multi-Country Case-Control Study  

PubMed Central

Bovine neonatal pancytopenia (BNP), a high fatality condition causing haemorrhages in calves aged less than 4 weeks, was first reported in 2007 in Germany and subsequently observed at low incidence in other European countries and New Zealand. A multi-country matched case-control study was conducted in 2011 to identify calf-level risk factors for BNP. 405 BNP cases were recruited from 330 farms in Belgium, France, Germany and the Netherlands by laboratory confirmation of farmer-reported cases. Up to four calves of similar age from the same farm were selected as controls (1154 calves). Risk factor data were collected by questionnaire. Multivariable modelling using conditional logistic regression indicated that PregSure®BVD (PregSure, Pfizer Animal Health) vaccination of the dam was strongly associated with BNP cases (adjusted matched Odds Ratio - amOR 17.8 first lactation dams; 95% confidence interval – ci 2.4, 134.4; p?=?0.005), and second or more lactation PregSure-vaccinated dams were more likely to have a case than first lactation vaccinated dams (amOR 2.2 second lactation; ci 1.1, 4.3; p?=?0.024; amOR 5.3 third or more lactation; ci 2.9, 9.8; p?=?<0.001). Feeding colostrum from other cows was strongly associated with BNP if the dam was not PregSure-vaccinated (amOR 30.5; ci 2.1, 440.5; p?=?0.012), but the effect was less if the dam was PregSure-vaccinated (amOR 2.1; ci 1.1, 4.0; p?=?0.024). Feeding exclusively dam’s milk was a higher risk than other types of milk (amOR 3.4; ci 1.6, 7.5; p?=?0.002). The population attributable fractions were 0.84 (ci 0.68, 0.92) for PregSure vaccination, 0.13 (ci 0.06, 0.19) for feeding other cows’ colostrum, and 0.15 (ci 0.08, 0.22) for feeding dam’s milk. No other calf-level factors were identified, suggesting that there are other important factors that are outside the scope of this study, such as genetics, which explain why BNP develops in some PregSure-colostrum-exposed calves but not in others. PMID:24312485

Jones, Bryony A.; Sauter-Louis, Carola; Henning, Joerg; Stoll, Alexander; Nielen, Mirjam; Van Schaik, Gerdien; Smolenaars, Anja; Schouten, Matthijs; den Uijl, Ingrid; Fourichon, Christine; Guatteo, Raphael; Madouasse, Aurélien; Nusinovici, Simon; Deprez, Piet; De Vliegher, Sarne; Laureyns, Jozef; Booth, Richard; Cardwell, Jackie M.; Pfeiffer, Dirk U.

2013-01-01

430

Endogenous cholinergic tone modulates spontaneous network level neuronal activity in primary cortical cultures grown on multi-electrode arrays  

PubMed Central

Background Cortical cultures grown long-term on multi-electrode arrays (MEAs) are frequently and extensively used as models of cortical networks in studies of neuronal firing activity, neuropharmacology, toxicology and mechanisms underlying synaptic plasticity. However, in contrast to the predominantly asynchronous neuronal firing activity exhibited by intact cortex, electrophysiological activity of mature cortical cultures is dominated by spontaneous epileptiform-like global burst events which hinders their effective use in network-level studies, particularly for neurally-controlled animat (‘artificial animal’) applications. Thus, the identification of culture features that can be exploited to produce neuronal activity more representative of that seen in vivo could increase the utility and relevance of studies that employ these preparations. Acetylcholine has a recognised neuromodulatory role affecting excitability, rhythmicity, plasticity and information flow in vivo although its endogenous production by cortical cultures and subsequent functional influence upon neuronal excitability remains unknown. Results Consequently, using MEA electrophysiological recording supported by immunohistochemical and RT-qPCR methods, we demonstrate for the first time, the presence of intrinsic cholinergic neurons and significant, endogenous cholinergic tone in cortical cultures with a characterisation of the muscarinic and nicotinic components that underlie modulation of spontaneous neuronal activity. We found that tonic muscarinic ACh receptor (mAChR) activation affects global excitability and burst event regularity in a culture age-dependent manner whilst, in contrast, tonic nicotinic ACh receptor (nAChR) activation can modulate burst duration and the proportion of spikes occurring within bursts in a spatio-temporal fashion. Conclusions We suggest that the presence of significant endogenous cholinergic tone in cortical cultures and the comparability of its modulatory effects to those seen in intact brain tissues support emerging, exploitable commonalities between in vivo and in vitro preparations. We conclude that experimental manipulation of endogenous cholinergic tone could offer a novel opportunity to improve the use of cortical cultures for studies of network-level mechanisms in a manner that remains largely consistent with its functional role. PMID:23530974

2013-01-01

431

Total cost estimation for implementing genome-enabled selection in a multi-level swine production system  

PubMed Central

Background Determining an animal’s genetic merit using genomic information can improve estimated breeding value (EBV) accuracy; however, the magnitude of the accuracy improvement must be large enough to recover the costs associated with implementing genome-enabled selection. One way to reduce costs is to genotype nucleus herd selection candidates using a low-density chip and to use high-density chip genotyping for animals that are used as parents in the nucleus breeding herd. The objective of this study was to develop a tool to estimate the cost structure associated with incorporating genome-enabled selection into multi-level commercial breeding programs. Results For the purpose of this deterministic study, it was assumed that a commercial pig is created from a terminal line sire and a dam that is a cross between two maternal lines. It was also assumed that all male and female selection candidates from the 1000 sow maternal line nucleus herds were genotyped at low density and all animals used for breeding at high density. With the assumptions used in this analysis, it was estimated that genome-enabled selection costs for a maternal line would be approximately US$0.082 per weaned pig in the commercial production system. A total of US$0.164 per weaned pig is needed to incorporate genome-enabled selection into the two maternal lines. Similarly, for a 600 sow terminal line nucleus herd and genotyping only male selection candidates with the low-density panel, the cost per weaned pig in the commercial herd was estimated to be US$0.044. This means that US$0.21 per weaned pig produced at the commercial level and sired by boars obtained from the nucleus herd breeding program needs to be added to the genetic merit value in order to break even on the additional cost required when genome-enabled selection is used in both maternal lines and the terminal line. Conclusions By modifying the input values, such as herd size and genotyping strategy, a flexible spreadsheet tool developed from this work can be used to estimate the additional costs associated with genome-enabled selection. This tool will aid breeders in estimating the economic viability of incorporating genome-enabled selection into their specific breeding program. PMID:24885089

2014-01-01

432

An SCR inverter for electric vehicles  

NASA Technical Reports Server (NTRS)

An inverter for an electric vehicle propulsion application has been designed and constructed to excite a polyphase induction motor from a fixed propulsion battery source. The inverter, rated at 35kW peak power, is fully regenerative and permits vehicle operation in both the forward and reverse directions. Thyristors are employed as the power switching devices arranged in a dc bus commutated topology. This paper describes the major role the controller plays in generating the motor excitation voltage and frequency to deliver performance similar to dc systems. Motoring efficiency test data for the controller are presented. It is concluded that an SCR inverter in conjunction with an ac induction motor is a viable alternative to present dc vehicle propulsion systems on the basis of performance and size criteria.

Latos, T.; Bosack, D.; Ehrlich, R.; Jahns, T.; Mezera, J.; Thimmesch, D.

1980-01-01

433

Transparent Multi-level Resistive Switching Phenomena Observed in ITO/RGO/ITO Memory Cells by the Sol-Gel Dip-Coating Method  

NASA Astrophysics Data System (ADS)

A reduced graphene oxide (RGO)-based transparent electronic memory cell with multi-level resistive switching (RS) was successfully realized by a dip-coating method. Using ITO/RGO/ITO structures, the memory device exhibited a transmittance above 80% (including the substrate) in the visible region and multi-level RS behavior in the 00, 01, 10, and 11 states by varying the pulse height from 2 V to 7 V. In the reliability test, the device exhibited a good endurance of over 105 cycles and a long data retention of over 105 s at 85°C in each state. We believe that the RGO-based transparent memory presented in this work could be a milestone for future transparent electronic devices.

Kim, Hee-Dong; Yun, Min Ju; Lee, Jae Hoon; Kim, Kyoeng Heon; Kim, Tae Geun

2014-04-01

434

Transparent Multi-level Resistive Switching Phenomena Observed in ITO/RGO/ITO Memory Cells by the Sol-Gel Dip-Coating Method  

PubMed Central

A reduced graphene oxide (RGO)-based transparent electronic memory cell with multi-level resistive switching (RS) was successfully realized by a dip-coating method. Using ITO/RGO/ITO structures, the memory device exhibited a transmittance above 80% (including the substrate) in the visible region and multi-level RS behavior in the 00, 01, 10, and 11 states by varying the pulse height from 2?V to 7?V. In the reliability test, the device exhibited a good endurance of over 105 cycles and a long data retention of over 105?s at 85°C in each state. We believe that the RGO-based transparent memory presented in this work could be a milestone for future transparent electronic devices. PMID:24714566

Kim, Hee-Dong; Yun, Min Ju; Lee, Jae Hoon; Kim, Kyoeng Heon; Kim, Tae Geun

2014-01-01

435

A study on the oil flow characteristics in the inverter rotary compressor  

NASA Astrophysics Data System (ADS)

In order to secure the reliability of the oil in the inverter rotary compressor used in the system multi-air conditioners in heating and cooling modes, it is necessary to study the oil flow characteristics which affect to the compressor efficiency. In this study, sight glasses were installed at the compressor and accumulator for oil flow measurements, and various experiments were performed to measure the amount of discharged oil for different refrigerant pipe lengths. On the basis of the experimental measurements, we compared the OCR (Oil Circulation Rate) results of the system multi-air conditioner for various operating conditions. The results are graphically depicted.

Kim, H. J.; Kim, Y. J.

2013-12-01

436

A Soft-Switching Inverter for High-Temperature Advanced Hybrid Electric Vehicle Traction Motor Drives  

SciTech Connect

The state-of-the-art hybrid electric vehicles (HEVs) require the inverter cooling system to have a separate loop to avoid power semiconductor junction over temperatures because the engine coolant temperature of 105?C does not allow for much temperature rise in silicon devices. The proposed work is to develop an advanced soft-switching inverter that will eliminate the device switching loss and cut down the power loss so that the inverter can operate at high-temperature conditions while operating at high switching frequencies with small current ripple in low inductance based permanent magnet motors. The proposed tasks also include high-temperature packaging and thermal modeling and simulation to ensure the packaged module can operate at the desired temperature. The developed module will be integrated with the motor and vehicle controller for dynamometer and in-vehicle testing to prove its superiority. This report will describe the detailed technical design of the soft-switching inverters and their test results. The experiments were conducted both in module level for the module conduction and switching characteristics and in inverter level for its efficiency under inductive and dynamometer load conditions. The performance will be compared with the DOE original specification.

None, None

2012-01-31

437

Experimental study on the performance of an inverter heat pump system with bypass orifices  

SciTech Connect

An experimental study was performed to investigate the optimum cycle of an inverter heat pump as a function of frequency. The performance of an inverter heat pump was measured with a variation of frequency and length of capillary tube, and applying a newly designed bypass orifice. The inverter heat pump with the standard capillary tube that was optimum size at the rated frequency and ASHRAE test condition ``A'' was tested by varying frequency. The optimum cycles were also investigated by changing the length of capillary tube at individual level of low, rated, and high frequency. Since the inverter heat pump with a capillary tube does not provide optimal cycles at all operating frequencies, a bypass orifice was invented to improve the performance of the system at the wide frequency range. The flow rate change of the bypass orifice with respect to frequency was higher than that of the capillary tube. As a results of applying the bypass orifice to the inverter heat pump system, the performance was enhanced in the low frequency level compared with the conventional expansion device of a capillary tube.

Choi, J.; Kim, Y.

1999-07-01

438

Collapse-revival phenomenon for different configurations of a three-level atom interacting with a field via multi-photon process and nonlinearities  

NASA Astrophysics Data System (ADS)

General formalisms of a three-level atom interacting with quantized fields under the mechanism of the multi-photon transition are investigated. The wave function is calculated in the context of the framework of the dressed states. The collapse-revival phenomenon dependence on the photon number is discussed. The influences of detuning, Kerr-like, coupling constants and various forms of the intensity-dependent coupling functional are analyzed. General conclusions reached are illustrated through numerical results.

Fahmy Obada, Abdel-Shafy; Hanoura, Sadek Ahmed; Eied, Abdel-Hameed

2014-02-01

439

Using multi-source satellite data for lake level modelling in ungauged basins: a case study for Lake Turkana, East Africa  

Microsoft Academic Search

Managing limited surface water resources is a great challenge in areas where ground-based data are either limited or unavailable. Direct or indirect measurements of surface water resources through remote sensing offer several advantages of monitoring in ungauged basins. A physical based hydrologic technique to monitor lake water levels in ungauged basins using multi-source satellite data such as satellite-based rainfall estimates,

N. M. Velpuri; G. B. Senay; K. O. Asante

2011-01-01

440

Multi-resolution level sets with shape priors: a validation report for 2D segmentation of prostate gland in T2W MR images.  

PubMed

The level set approach to segmentation of medical images has received considerable attention in recent years. Evolving an initial contour to converge to anatomical boundaries of an organ or tumor is a very appealing method, especially when it is based on a well-defined mathematical foundation. However, one drawback of such evolving method is its high computation time. It is desirable to design and implement algorithms that are not only accurate and robust but also fast in execution. Bresson et al. have proposed a variational model using both boundary and region information as well as shape priors. The latter can be a significant factor in medical image analysis. In this work, we combine the variational model of level set with a multi-resolution approach to accelerate the processing. The question is whether a multi-resolution context can make the segmentation faster without affecting the accuracy. As well, we investigate the question whether a premature convergence, which happens in a much shorter time, would reduce accuracy. We examine multiple semiautomated configurations to segment the prostate gland in T2W MR images. Comprehensive experimentation is conducted using a data set of a 100 patients (1,235 images) to verify the effectiveness of the multi-resolution level set with shape priors. The results show that the convergence speed can be increased by a factor of ??2.5 without affecting the segmentation accuracy. Furthermore, a premature convergence approach drastically increases the segmentation speed by a factor of ??17.9. PMID:24865859

Al-Qunaieer, Fares S; Tizhoosh, Hamid R; Rahnamayan, Shahryar

2014-12-01

441

Variable universe adaptive fuzzy control on the quadruple inverted pendulum  

Microsoft Academic Search

This paper focuses on the control problem of the quadruple inverted pendulum by variable universe adaptive fuzzy control.\\u000a First, the mathematical model on the quadruple inverted pendulum is described and its controllability is versified. Then,\\u000a an efficient controller on the quadruple inverted pendulum is designed by using variable universe adaptive fuzzy control theory.\\u000a Finally the simulation of the quadruple inverted

Hongxing Li; Miao Zhihong; Wang Jiayin

2002-01-01

442

"In Situ" Generation of Compressed Inverted Files.  

ERIC Educational Resources Information Center

Discussion of index construction for large text collections highlights a new indexing algorithm designed to create large compressed inverted indexes "in situ." Topics include a computational model, inversion, index compression, merging, experimental test results, effect on retrieval performance, memory restrictions, and dynamic collections.…

Moffat, Alistair; Bell, Timothy A. H.

1995-01-01

443

Inverted drop testing and neck injury potential.  

PubMed

Inverted drop testing of vehicles is a methodology that has long been used by the automotive industry and researchers to test roof integrity and is currently being considered by the National Highway Traffic Safety Administration as a roof strength test. In 1990 a study was reported which involved 8 dolly rollover tests and 5 inverted drop tests. These studies were conducted with restrained Hybrid III instrumented Anthropometric Test Devices (ATD) in production and rollcaged vehicles to investigate the relationship between roof strength and occupant injury potential. The 5 inverted drop tests included in the study provided a methodology producing "repeatable roof impacts" exposing the ATDs to the similar impact environment as those seen in the dolly rollover tests. Authors have conducted two inverted drop test sets as part of an investigation of two real world rollover accidents. Hybrid-III ATD's were used in each test with instrumented head and necks. Both test sets confirm that reduction of roof intrusion and increased headroom can significantly enhance occupant protection. In both test pairs, the neck force of the dummy in the vehicle with less crush and more survival space was significantly lower. Reduced roof crush and dynamic preservation of the occupant survival space resulted in only minor occupant contact and minimal occupant loading, establishing a clear causal relationship between roof crush and neck injuries. PMID:12724903

Forrest, Stephen; Herbst, Brian; Meyer, Steve; Sances, Anthony; Kumaresan, Srirangam

2003-01-01

444

Attitude control of a triple inverted pendulum  

Microsoft Academic Search

The paper is concerned with the attitude control of a triple inverted pendulum. The lowest hinge is free for rotation and the torques of the upper two hinges are manipulated not only to stabilize the pendulum but also to control its attitude. The control system is designed by using CAD developed by the author and is realized by a minicomputer.

K. FURUT; T. OCHIAI; N. ONO

1984-01-01

445

Delta modulation strategies for resonant link inverters  

Microsoft Academic Search

The suitability of delta modulation strategies for resonant link inverters is explored in detail. The control and spectral characteristics of various delta modulators are examined in an effort to develop a model for the same. The more fundamental question of comparing delta modulation systems with conventional pulse-width-modulated (PWM) systems, given similar devices, is addressed, and it shown that the former

MUSTANSIR H. KHERALUWALA; DEEPAKRAJ M. DIVAN

1990-01-01

446

The Internet and the Inverted Classroom.  

ERIC Educational Resources Information Center

Describes a Web site that is for an undergraduate principles of microeconomics course and a main component of "The Inverted Classroom" in which lectures take place outside of class. Explains that the Web site is divided into four sections: (1) the classroom; (2) the desk; (3) the coffee shop; and (4) the library. (CMK)

Lage, Maureen J.; Platt, Glenn

2000-01-01

447

A Prefix Trie Index for Inverted Files.  

ERIC Educational Resources Information Center

Applies a prefix trie index, or trie hashing, to the problem of providing fast search times, fast load times, and fast update properties in a bibliographic or full-text retrieval system with inverted files. Statistics are given for a test database consisting of an online catalog at the University of Western Ontario. (Author/LRW)

Nelson, Michael J.

1997-01-01

448

Source Inverter for Residential Photovoltaic Systems  

Microsoft Academic Search

This paper proposes a Z-source inverter system for a split-phase grid-connected photovoltaic system. The operation principle, control method, and characteristics of the system are presented. A comparison between the new and traditional system configurations is performed. Simulation and experimental results are also shown to verify the proposed circuit and analysis

Yi Huang; Miaosen Shen; Fang Z. Peng; Jin Wang

2006-01-01

449

Pulse width modulation inverter with battery charger  

DOEpatents

An inverter is connected between a source of DC power and a three-phase AC induction motor, and a microprocessor-based circuit controls the inverter using pulse width modulation techniques. In the disclosed method of pulse width modulation, both edges of each pulse of a carrier pulse train are equally modulated by a time proportional to sin .theta., where .theta. is the angular displacement of the pulse center at the motor stator frequency from a fixed reference point on the carrier waveform. The carrier waveform frequency is a multiple of the motor stator frequency. The modulated pulse train is then applied to each of the motor phase inputs with respective phase shifts of 120.degree. at the stator frequency. Switching control commands for electronic switches in the inverter are stored in a random access memory (RAM) and the locations of the RAM are successively read out in a cyclic manner, each bit of a given RAM location controlling a respective phase input of the motor. The DC power source preferably comprises rechargeable batteries and all but one of the electronic switches in the inverter can be disabled, the remaining electronic switch being part of a "flyback" DC-DC converter circuit for recharging the battery.

Slicker, James M. (Union Lake, MI)

1985-01-01

450

Pulse width modulation inverter with battery charger  

NASA Technical Reports Server (NTRS)

An inverter is connected between a source of DC power and a three-phase AC induction motor, and a microprocessor-based circuit controls the inverter using pulse width modulation techniques. In the disclosed method of pulse width modulation, both edges of each pulse of a carrier pulse train are equally modulated by a time proportional to sin .theta., where .theta. is the angular displacement of the pulse center at the motor stator frequency from a fixed reference point on the carrier waveform. The carrier waveform frequency is a multiple of the motor stator frequency. The modulated pulse train is then applied to each of the motor phase inputs with respective phase shifts of 120.degree. at the stator frequency. Switching control commands for electronic switches in the inverter are stored in a random access memory (RAM) and the locations of the RAM are successively read out in a cyclic manner, each bit of a given RAM location controlling a respective phase input of the motor. The DC power source preferably comprises rechargeable batteries and all but one of the electronic switches in the inverter can be disabled, the remaining electronic switch being part of a flyback DC-DC converter circuit for recharging the battery.

Slicker, James M. (Inventor)

1985-01-01

451

A delta configured auxiliary resonant snubber inverter  

SciTech Connect

A delta ({Delta}) configured auxiliary resonant snubber inverter is developed to overcome the voltage floating problem in a wye (Y) configured resonant snubber inverter. The proposed inverter is to connect auxiliary resonant branches between phase outputs to avoid a floating point voltage which may cause over-voltage failure of the auxiliary switches. Each auxiliary branch consists of a resonant inductor and a reverse blocking auxiliary switch. Instead of using an anti-paralleled diode to allow resonant current to flow in the reverse direction, as in the Y-configured version, the resonant branch in the {Delta}-configured version must block the negative voltage, typically done by a series diode. This paper shows single-phase and three-phase versions of {Delta}-configured resonant snubber inverters and describes in detail the operating principle of a single-phase version. The extended three-phase version is proposed with non-adjacent state space vector modulation. For hardware implementation, a single-phase 1-kW unit and a three-phase 100-kW unit were built to prove the concept. Experimental results show the superiority of the proposed topology.

Lai, J.S.; Young, R.W.; Ott, G.W. Jr.; McKeever, J.W. [Oak Ridge National Lab., TN (United States). Engineering Technology Div.; Peng, F.Z. [Univ. of Tennessee, Knoxville, TN (United States)]|[Oak Ridge National Lab., TN (United States)

1995-09-01

452

New Inverter Supplies for High Horsepower Drives  

Microsoft Academic Search

A review of basic ac induction motor characteristics establishes the requirements of a static ac variable-speed drive. Both voltage and frequency impressed onto an ac motor must be programmed in correct proportion if required operating torque is to be maintained. The means of voltage control used characterizes the various inverter designs and likewise dictates their limitations. Pulsewidth modulation for variable

Richard P. Veres

1970-01-01

453

Inverter Matrix for the Clementine Mission  

NASA Technical Reports Server (NTRS)

An inverter matrix test circuit was designed for the Clementine space mission and is built into the RRELAX (Radiation and Reliability Assurance Experiment). The objective is to develop a circuit that will allow the evaluation of the CMOS FETs using a lean data set in the noisy spacecraft environment.

Buehler, M. G.; Blaes, B. R.; Tardio, G.; Soli, G. A.

1994-01-01

454

Two-Stage Series-Resonant Inverter  

NASA Technical Reports Server (NTRS)

Two-stage inverter includes variable-frequency, voltage-regulating first stage and fixed-frequency second stage. Lightweight circuit provides regulated power and is invulnerable to output short circuits. Does not require large capacitor across ac bus, like parallel resonant designs. Particularly suitable for use in ac-power-distribution system of aircraft.

Stuart, Thomas A.

1994-01-01

455

Inverted Fluorescent Microscope Procedure Taking an Image  

E-print Network

Inverted Fluorescent Microscope Procedure Taking an Image 1. Load the program "QCapture Pro" 2 on the White Light Source using the button on the main body of the microscope (it is coordinate with the box. Click on the "Preview" Tab. 8. Click on "Start Preview" to get a live feed from the Microscope. 9

456

Epi-Fluorescence Inverted Microscope (Zeiss,  

E-print Network

Epi-Fluorescence Inverted Microscope (Zeiss, Observer Z1) April 2013 #12;Start Up cont. · Turn on the microscope power supply · Press the ON/OFF button on the microscope to turn on the microscope control panel the power switch). · Press "Microscope" on the small touchscreen to setup the microscope settings

Subramanian, Venkat

457

High-power, null-type, inverted pendulum thrust stand.  

PubMed

This article presents the theory and operation of a null-type, inverted pendulum thrust stand. The thrust stand design supports thrusters having a total mass up to 250 kg and measures thrust over a range of 1 mN to 5 N. The design uses a conventional inverted pendulum to increase sensitivity, coupled with a null-type feature to eliminate thrust alignment error due to deflection of thrust. The thrust stand position serves as the input to the null-circuit feedback control system and the output is the current to an electromagnetic actuator. Mechanical oscillations are actively damped with an electromagnetic damper. A closed-loop inclination system levels the stand while an active cooling system minimizes thermal effects. The thrust stand incorporates an in situ calibration rig. The thrust of a 3.4 kW Hall thruster is measured for thrust levels up to 230 mN. The uncertainty of the thrust measurements in this experiment is +/-0.6%, determined by examination of the hysteresis, drift of the zero offset and calibration slope variation. PMID:19485530

Xu, Kunning G; Walker, Mitchell L R

2009-05-01

458

A Novel Inductor-less DC-AC Cascaded H-bridge Multilevel Boost Inverter for Electric/Hybrid Electric Vehicle Applications  

SciTech Connect

This paper presents an inductorless cascaded H- bridge multilevel boost inverter for EV and HEV applications. Currently available power inverter systems for HEVs use a DC- DC boost converter to boost the battery voltage for a traditional 3-phase inverter. The present HEV traction drive inverters have low power density, are expensive, and have low efficiency because they need a bulky inductor. An inductorless cascaded H-bridge multilevel boost inverter for EV and HEV applications is proposed in this paper. Traditionally, each H-bridge needs a DC power supply. The proposed inductorless cascaded H-bridge multilevel boost inverter uses a standard 3-leg inverter (one leg for each phase) and an H-bridge in series with each inverter leg which uses a capacitor as the DC power source. Fundamental switching scheme is used to do modulation control and to produce a 5-level phase voltage. Experiments show that the proposed inductorless DC-AC cascaded H-bridge multilevel boost inverter can output a boosted AC voltage.

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

2007-01-01

459

Aggregation-Based Learning in the Inverted Pendulum Problem  

E-print Network

Aggregation-Based Learning in the Inverted Pendulum Problem Gerald van den Berg Advised by Prof to the inverted pendulum task. This is a particularly challenging task as we work with a relatively uninformative The task of balancing an inverted pendulum (also known as the pole-balancing problem) was originally used

Torquato, Salvatore

460

Hybrid Stabilizing Control for the Spatial Double Inverted Pendulum  

E-print Network

Hybrid Stabilizing Control for the Spatial Double Inverted Pendulum Xinjilefu, Vincent Hayward, and Hannah Michalska Abstract The spatial double inverted pendulum actuated at the hip, but not at the foot is the double spatial inverted pendulum which is seen in Fig. 1. Xinjelifu and Hannah Michalska Mc

Hayward, Vincent

461

Design for control of wheeled inverted pendulum Hari Vasudevan  

E-print Network

Design for control of wheeled inverted pendulum platforms Hari Vasudevan Department of Mechanical of design for wheeled inverted pendulum (WIP) platforms with the aim of under- standing the effect of design and constructed with minimal iterative experimen- tation. 1 Introduction The inverted pendulum has widely

Dollar, Aaron M.

462

MODELLING AND STABILISATION OF A SPHERICAL INVERTED PENDULUM  

E-print Network

MODELLING AND STABILISATION OF A SPHERICAL INVERTED PENDULUM Guangyu Liu ,1 Dragan Nesi´c Iven inverted pendulum based on the forwarding technique. We first explore the forwarding structure of the spherical inverted pendulum model and then find a control law to stabilize the angle variables. Next, we

Nesic, Dragan

463

Multiple time scale numerical methods for the inverted pendulum problem  

E-print Network

Multiple time scale numerical methods for the inverted pendulum problem Richard Sharp1, Yen (HMM) [1]. We apply the methods to compute the averaged path of the inverted pendulum under a highly and thus compute the average path of the inverted pendulum. 1 Introduction The focus of this paper

Tsai, Yen-Hsi Richard

464

MULTIPLE TIME SCALE NUMERICAL METHODS FOR THE INVERTED PENDULUM PROBLEM  

E-print Network

MULTIPLE TIME SCALE NUMERICAL METHODS FOR THE INVERTED PENDULUM PROBLEM RICHARD SHARP, YEN-HSI TSAI multiscale methods (HMM) [1]. We apply the methods to compute the averaged path of the inverted pendulum approximate the averaged equation and thus compute the average path of the inverted pendulum. 1. INTRODUCTION

Soatto, Stefano

465