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1

A novel structure of multi-level high voltage source inverter  

Microsoft Academic Search

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

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

1993-01-01

2

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

3

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

Microsoft Academic Search

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

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

1999-01-01

4

Fault-tolerant three-level inverter  

DOEpatents

A method for driving a neutral point clamped three-level inverter is provided. In one exemplary embodiment, DC current is received at a neutral point-clamped three-level inverter. The inverter has a plurality of nodes including first, second and third output nodes. The inverter also has a plurality of switches. Faults are checked for in the inverter and predetermined switches are automatically activated responsive to a detected fault such that three-phase electrical power is provided at the output nodes.

Edwards, John; Xu, Longya; Bhargava, Brij B.

2006-12-05

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

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

Microsoft Academic Search

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

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

1999-01-01

7

Multi-Input Inverter for Grid-Connected Hybrid PV\\/Wind Power System  

Microsoft Academic Search

The objective of this paper is to propose a novel multi-input inverter for the grid-connected hybrid photovoltaic (PV)\\/wind power system in order to simplify the power system and reduce the cost. The proposed multi-input inverter consists of a buck\\/buck-boost fused multi-input dc-dc converter and a full-bridge dc-ac inverter. The output power characteristics of the PV array and the wind turbine

Yaow-Ming Chen; Yuan-Chuan Liu; Shih-Chieh Hung; Chung-Sheng Cheng

2007-01-01

8

A three-level MOSFET inverter for low power drives  

Microsoft Academic Search

This paper proposes operating a three-level neutral point clamped (NPC) inverter using a two-level PWM method. This allows for the clamping diodes to be rated at a fraction of the main switches due to their low average current requirement. The use of a charge pump as a low cost method to obtain the isolated gate drive power supplies is extended

B. A. Welchko; M. Bde. R. Correa; T.A. Lipo

2002-01-01

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

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

E-print Network

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

Tolbert, Leon M.

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

Short circuit and overcurrent protection of IGCT-based three-level NPC inverters  

Microsoft Academic Search

In this paper, a new method for protection of IGCT based three-level NPC inverters is introduced and compared with other protection methods already presented in the technical literature. A system for fast overcurrent detection and inverter tripping is also presented as well as a complete discussion of the inverter design issues involved in the proposed protection scheme. Simulation results are

Manoel EUstAquio dos Santos; Bde. J. C. Filho

2004-01-01

13

Multi-level converters for three-phase photovoltaic applications  

E-print Network

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

Lehman, Brad

14

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

Microsoft Academic Search

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

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

2007-01-01

15

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

Microsoft Academic Search

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

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

2006-01-01

16

11Level cascaded H-bridge grid-tied inverter interface with solar panels  

Microsoft Academic Search

This paper presents a single-phase 11-level (5 H-bridges) cascade multilevel DC-AC grid-tied inverter. Each inverter bridge is connected to a 200 W solar panel. OPAL-RT lab was used as the hardware in the loop (HIL) real-time control system platform where a Maximum Power Point Tracking (MPPT) algorithm was implemented based on the inverter output power to assure optimal operation of

Faete Filho; Yue Cao; Leon M. Tolbert

2010-01-01

17

Performance of FOC IM drive in SVM controlled five-level diode-clamped inverter  

Microsoft Academic Search

Multilevel inverters provide cost-effective solution in the medium voltage energy market. These converters synthesize the output voltage waveform from several steps of dc input source which approaches to sinusoidal waveform and minimizes the harmonic distortions. This paper discusses the features of 5-level diode-clamped inverter. The application of diode clamped multilevel inverter in Field-Oriented-Control (FOC) scheme of induction motor drive using

U. V Patil; H. M. Suryawanshi; M. M. Renge

2012-01-01

18

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

Microsoft Academic Search

Design and fabrication of a novel four cell cylindrically inverted multi-cell (CIM) solar thermionic converter for space power applications is in progress. When heated externally, the converter (8 cm diameter and 35 cm long) is capable of producing up to 492 W of electric power. The emitters operate at 2000 K while the collectors operate at 1050 K. Key components

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

2005-01-01

19

An Active Anti-Islanding Algorithm for Inverter Based Multi-Source DER Systems  

Microsoft Academic Search

Islanding detection is an essential function for safety and reliability in grid connected distributed generation (DG) systems. Several methods for islanding detection are proposed, but most of them are not efficient for multi-source configurations, or they may produce important power quality degradation getting worst with DG penetration increasing. This paper presents an active islanding detection algorithm for voltage source inverter

Alben Cardenas; Kodjo Agbossou; Mamadou L. Doumbia

2009-01-01

20

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

Microsoft Academic Search

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

T. Bruckner; S. Bemet

2001-01-01

21

Reduced switching stress in high-voltage IGBT inverters via a three-level structure  

Microsoft Academic Search

High voltage (3.3-4.5 kV) insulated gate bipolar transistors (HVIGBTs) are limited in SOA and ability to be effectively used in hard switched 2-level PWM inverters. The proposed operation sequence for the well known 3-level inverter allows use of HVIGBTs at near-rated voltage while cutting switching loss in half and allowing 3-level PWM for improved harmonics spectrum. Simulation and laboratory results

W. E. Brumsickle; D. M. Divan; T.A. Lipo

1998-01-01

22

Three Level DC-to-AC Power Inverter for Power Grid Operation  

Microsoft Academic Search

In case of medium voltage (several tens up to hundred volts on DC-side) solar inverter applications a DC- to-DC converter for voltage level adaptation is required in front of the DC-to-AC inverter. This leads to a two-stage concept with accumulation of the losses. In our case a concept was chosen, where the efficiency in each stage is maximized by usage

K. H. EDELMOSER

23

Soft-switched three-level capacitor clamping inverter with clamping voltage stabilization  

Microsoft Academic Search

This paper proposes a zero-voltage-switching scheme for the three-level capacitor clamping inverter. The proposed small-rating auxiliary circuit ensures not only zero-voltage switching of the main switches and zero-current switching of the auxiliary switches, but the clamping capacitor voltage of the inverter is also stabilized. The scheme prevents any voltage or current spikes from happening over the main or auxiliary switches

Xiaoming Yuan; Ivo Barbi

2000-01-01

24

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

SciTech Connect

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

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

2010-07-15

25

A novel multilevel inverter topology based on multi-winding multi-tapped transformers for improved wave shape requirements  

Microsoft Academic Search

The present work proposes a simple cost effective multilevel topology for generating high quality sinusoidal AC waveform based onmulti-tapped multi-winding transformer switching technique. Multi-winding multi-tapped transformers are used to aid the multi-level switching process which guarantees a large number of intermediate switching levels. Each secondary tapping can act as a separate DC source derived from the single DC supply input

E. S Deepak; C. S Anil; S Sanjay; C Febi; K. R Sajina

2011-01-01

26

Applications of cascade multilevel inverters.  

PubMed

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

Peng, Fang-zen; Qian, Zhao-ming

2003-01-01

27

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

Microsoft Academic Search

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

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

1996-01-01

28

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

SciTech Connect

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

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

2009-01-01

29

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

E-print Network

dielectric breakdown of individual MOS capacitors and MOSFETs (for an overview, see [3]). However, there have) of degraded inverters are simulated using a new circuit model. At the transistor level, both the PMOSFET breakdown and reliability has become an important issue because it might be a limiting factor in the future

Baker, R. Jacob

30

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

Microsoft Academic Search

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

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

2000-01-01

31

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

Microsoft Academic Search

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

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

1999-01-01

32

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

33

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

E-print Network

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

Tolbert, Leon M.

34

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

35

Static Var Compensator and Active Power Filter With Power Injection Capability, Using 27Level Inverters and Photovoltaic Cells  

Microsoft Academic Search

An active power filter and static var compensator with active power generation capability has been implemented using a 27-level inverter. Each phase of this inverter is composed of three ldquoHrdquo bridges, all of them connected to the same dc link and their outputs connected through output transformers scaled in the power of three. The filter can compensate load currents with

Patricio Flores; Juan Dixon; Micah Ortúzar; Rodrigo Carmi; Pablo Barriuso; Luis Moran

2009-01-01

36

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

Microsoft Academic Search

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

F. Wang

2000-01-01

37

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

Microsoft Academic Search

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

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

1997-01-01

38

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

Microsoft Academic Search

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

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

1994-01-01

39

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

40

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

PubMed Central

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

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

2014-01-01

41

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

Microsoft Academic Search

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

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

1998-01-01

42

Multi-level modulation codes and multi-stage decoding  

NASA Technical Reports Server (NTRS)

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

Lin, Shu

1990-01-01

43

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

E-print Network

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

Mi, Chunting "Chris"

44

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

45

Jupiter's Multi-level Clouds  

NASA Technical Reports Server (NTRS)

Clouds and hazes at various altitudes within the dynamic Jovian atmosphere are revealed by multi-color imaging taken by the Near-Infrared Mapping Spectrometer (NIMS) onboard the Galileo spacecraft. These images were taken during the second orbit (G2) on September 5, 1996 from an early-morning vantage point 2.1 million kilometers (1.3 million miles) above Jupiter. They show the planet's appearance as viewed at various near-infrared wavelengths, with distinct differences due primarily to variations in the altitudes and opacities of the cloud systems. The top left and right images, taken at 1.61 microns and 2.73 microns respectively, show relatively clear views of the deep atmosphere, with clouds down to a level about three times the atmospheric pressure at the Earth's surface.

By contrast, the middle image in top row, taken at 2.17 microns, shows only the highest altitude clouds and hazes. This wavelength is severely affected by the absorption of light by hydrogen gas, the main constituent of Jupiter's atmosphere. Therefore, only the Great Red Spot, the highest equatorial clouds, a small feature at mid-northern latitudes, and thin, high photochemical polar hazes can be seen. In the lower left image, at 3.01 microns, deeper clouds can be seen dimly against gaseous ammonia and methane absorption. In the lower middle image, at 4.99 microns, the light observed is the planet's own indigenous heat from the deep, warm atmosphere.

The false color image (lower right) succinctly shows various cloud and haze levels seen in the Jovian atmosphere. This image indicates the temperature and altitude at which the light being observed is produced. Thermally-rich red areas denote high temperatures from photons in the deep atmosphere leaking through minimal cloud cover; green denotes cool temperatures of the tropospheric clouds; blue denotes cold of the upper troposphere and lower stratosphere. The polar regions appear purplish, because small-particle hazes allow leakage and reflectivity, while yellowish regions at temperate latitudes may indicate tropospheric clouds with small particles which also allow leakage. A mix of high and low-altitude aerosols causes the aqua appearance of the Great Red Spot and equatorial region.

The Jet Propulsion Laboratory manages the Galileo mission for NASA's Office of Space Science, Washington, DC.

This image and other images and data received from Galileo are posted on the World Wide Web Galileo mission home page at http://galileo.jpl.nasa.gov.

1997-01-01

46

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

E-print Network

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

Tolbert, Leon M.

47

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

SciTech Connect

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

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

2007-01-01

48

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

49

Multi-stage decoding of multi-level modulation codes  

NASA Technical Reports Server (NTRS)

Various types of multi-stage decoding for multi-level modulation codes are investigated. It is shown that if the component codes of a multi-level modulation code and types of decoding at various stages are chosen properly, high spectral efficiency and large coding gain can be achieved with reduced decoding complexity. Particularly, it is shown that the difference in performance between the suboptimum multi-stage soft-decision maximum likelihood decoding of a modulation code and the single-stage optimum soft-decision decoding of the code is very small, only a fraction of dB loss in signal to noise ratio at a bit error rate (BER) of 10(exp -6).

Lin, Shu; Kasami, Tadao; Costello, Daniel J., Jr.

1991-01-01

50

Achievement of a 10 kV IMD system by 6 kV three-level NPC inverter with IGCTs in series connection applied in water works  

Microsoft Academic Search

A high power 10 kV IMD (induction motor drives) system supplied by a 6 kV three-level NPC (neutral point clamped) inverter with IGCTs (integrated gate commutated thyristors) in series connection, which applied in water works has been developed and achieved. The designed three-level inverter system includes a 24 pulses rectifier, a diode NPC three-level medium voltage VSI (voltage source inverter).

Qingguang Yu; Xiaoming Zhang; Wenhua Liu; Qiang Song

2004-01-01

51

Space Vector based pulse Density Modulation scheme for two level voltage source inverter  

Microsoft Academic Search

A Space Vector based Pulse Density Modulation scheme for spreading the spectra of Voltage Source Inverters is proposed in this paper. The proposed scheme employs first order Sigma-Delta Modulator. The principle of Vector Quantization is applied for quantizing the reference voltage Space Vector in the Sigma Delta Modulator. For the spatial quantization, the inverter voltage vector space is divided into

Biji Jacob; M. R. Baiju

2011-01-01

52

Performance comparison of DTC and FOC induction motor drive in five level diode clamped inverter  

Microsoft Academic Search

Robustness, fast dynamic response and simplicity of direct torque control and field oriented control methods of induction motor can successfully replace dc motors. The development in multilevel inverter topologies and their control techniques made has improved the performance of these drives to the industrial requirements. The performances of these drives with diode-clamped multilevel inverter are compared and the results presented

U. V Patil; H. M. Suryawanshi; M. M. Renge

2012-01-01

53

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

Microsoft Academic Search

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

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

1998-01-01

54

Space vector modulation strategy applied to interphase transformers-based five-level current source inverters for electric propulsion  

Microsoft Academic Search

A propulsion system based on the multilevel current source inverter (MCSI), which enables voltageboosting and high current handling capabilities, is an interesting solution for electric propulsion. In such a system, the associated capacitance values are small and the voltages at the motor terminals are nearly sinusoidal. Such a MCSI employing interphase transformers to produce different input current levels presents the

Bruno S. Dupczak; Marcelo L. Heldwein; Arnaldo J. Perin

2011-01-01

55

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

56

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; Lai, Jih-Sheng

2001-04-03

57

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

58

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

59

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

NASA Astrophysics Data System (ADS)

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

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

2014-03-01

60

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

Microsoft Academic Search

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

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

1997-01-01

61

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

Microsoft Academic Search

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

Fei Wang

2002-01-01

62

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

Microsoft Academic Search

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

Thomas Brückner; Steffen Bernet

2001-01-01

63

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

64

Multi-level coupled cluster theory.  

PubMed

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. PMID:25494730

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

2014-12-14

65

Level set method for simulating multi-phase multi-component dendritic solidification  

E-print Network

Level set method for simulating multi-phase multi-component dendritic solidification Lijian Tan to model microstructure evolution in multi-phase multi-component alloy systems. The `constraint-based level analytical solutions as well as with numerical solutions based on the phase-field method and front tracking

Zabaras, Nicholas J.

66

Electronic multi-purpose material level sensor  

DOEpatents

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

McEwan, T.E.

1997-03-11

67

Electronic multi-purpose material level sensor  

DOEpatents

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

McEwan, Thomas E. (Livermore, CA)

1997-01-01

68

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

NASA Astrophysics Data System (ADS)

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

Draou, Azeddine

2012-12-01

69

Probabilistic Multi-Scale, Multi-Level, Multi-Disciplinary Analysis and Optimization of Engine Structures  

NASA Technical Reports Server (NTRS)

Aircraft engines are assemblies of dynamically interacting components. Engine updates to keep present aircraft flying safely and engines for new aircraft are progressively required to operate in more demanding technological and environmental requirements. Designs to effectively meet those requirements are necessarily collections of multi-scale, multi-level, multi-disciplinary analysis and optimization methods and probabilistic methods are necessary to quantify respective uncertainties. These types of methods are the only ones that can formally evaluate advanced composite designs which satisfy those progressively demanding requirements while assuring minimum cost, maximum reliability and maximum durability. Recent research activities at NASA Glenn Research Center have focused on developing multi-scale, multi-level, multidisciplinary analysis and optimization methods. Multi-scale refers to formal methods which describe complex material behavior metal or composite; multi-level refers to integration of participating disciplines to describe a structural response at the scale of interest; multidisciplinary refers to open-ended for various existing and yet to be developed discipline constructs required to formally predict/describe a structural response in engine operating environments. For example, these include but are not limited to: multi-factor models for material behavior, multi-scale composite mechanics, general purpose structural analysis, progressive structural fracture for evaluating durability and integrity, noise and acoustic fatigue, emission requirements, hot fluid mechanics, heat-transfer and probabilistic simulations. Many of these, as well as others, are encompassed in an integrated computer code identified as Engine Structures Technology Benefits Estimator (EST/BEST) or Multi-faceted/Engine Structures Optimization (MP/ESTOP). The discipline modules integrated in MP/ESTOP include: engine cycle (thermodynamics), engine weights, internal fluid mechanics, cost, mission and coupled structural/thermal, various composite property simulators and probabilistic methods to evaluate uncertainty effects (scatter ranges) in all the design parameters. The objective of the proposed paper is to briefly describe a multi-faceted design analysis and optimization capability for coupled multi-discipline engine structures optimization. Results are presented for engine and aircraft type metrics to illustrate the versatility of that capability. Results are also presented for reliability, noise and fatigue to illustrate its inclusiveness. For example, replacing metal rotors with composites reduces the engine weight by 20 percent, 15 percent noise reduction, and an order of magnitude improvement in reliability. Composite designs exist to increase fatigue life by at least two orders of magnitude compared to state-of-the-art metals.

Chamis, Christos C.; Abumeri, Galib H.

2000-01-01

70

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

NASA Astrophysics Data System (ADS)

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

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

2012-05-01

71

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

72

Multi-Level Annotation of Natural Scenes Using Dominant Image  

E-print Network

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

Fan, Jianping

73

Investigation of Circuit-Level Oxide Degradation and its Effect on CMOS Inverter Operation and MOSFET Characteristics  

E-print Network

reliability, CMOS, dielectric breakdown, gate oxide reliability, inverter degradation, MOSFEET degradation on gate dielectric breakdown of individual MOS capacitors and an increasing number on MOSFETs (for) of various magnitudes to the input of the inverter. A novel circuit model is used to simulate the voltage

Baker, R. Jacob

74

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

E-print Network

significantly reduced. The filter was designed to work as voltage source and operates as harmonic isolator frequencies), parallel and series resonance with source-voltage harmonics, and filtering Manuscript received-Level Inverter for Hybrid-Series Active Power Filter, Using Industrial Controller Alexander Varschavsky, Juan

Catholic University of Chile (Universidad Católica de Chile)

75

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.

76

Multi-Level Sequential Pattern Mining Based on Prime Encoding  

NASA Astrophysics Data System (ADS)

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

Lianglei, Sun; Yun, Li; Jiang, Yin

77

Squeezed light from conventionally pumped multi-level lasers  

NASA Technical Reports Server (NTRS)

We have calculated the amplitude squeezing in the output of several conventionally pumped multi-level lasers. We present results which show that standard laser models can produce significantly squeezed outputs in certain parameter ranges.

Ralph, T. C.; Savage, C. M.

1992-01-01

78

Hydraulic Design of A MultiLevel Intake Structure  

Microsoft Academic Search

\\u000a In the present work design of a multi level intake is explained for a 65m high rock fill dam. This multi-level intake structure\\u000a was designed for irrigation purposes with a design discharge of 20 m3\\/s. This structure, standing vertically in the reservoir,\\u000a was 65m high and had a rectangular cross section which its dimensions were different at different elevations. Four

K. Safavi; A. R. Karaminejad; H. Jamali; H. A Sarkardeh; A. R. Zarrati

79

Multilevel DC link inverter  

DOEpatents

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

Su, Gui-Jia

2003-06-10

80

Robust Multi-Partite Multi-Level Quantum Protocols  

E-print Network

We present a tripartite three-level state that allows a secret sharing protocol among the three parties, or a quantum key distribution protocol between any two parties. The state used in this scheme contains entanglement even after one system is traced out. We show how to utilize this residual entanglement for quantum key distribution purposes, and propose a realization of the scheme using entanglement of orbital angular momentum states of photons.

Hideomi Nihira; C. R. Stroud Jr

2004-12-13

81

A general circuit topology of multilevel inverter  

Microsoft Academic Search

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

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

1991-01-01

82

A dual inverter with integrated energy storage for wind power systems  

Microsoft Academic Search

This paper explores the possibility of using grid side inverter as an interface to connect energy storage systems. A dual inverter system, formed by cascading two 2-level inverters through a coupling transformer, is used as the testing model. The inverters are named as “main inverter” and “auxiliary inverter”. The main inverter is powered by the rectified output of the wind

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

2010-01-01

83

Perennial Dreams ognition is a complex, multi-faceted and multi-level phenomenon. Unraveling it,  

E-print Network

Prologue Perennial Dreams ognition is a complex, multi-faceted and multi-level phenomenon, and intellectual threads that can be best understood through the relationships among its components. AI is a dream -- a dream of the creation of things in the human image, a dream that reveals the human quest for immortality

Indiana University

84

Transforming loops to recursion for multi-level memory hierarchies  

Microsoft Academic Search

Recently, there have been several experimental and theoretical results showing significant performance benefits of recursive algorithms on both multi-level memory hierarchies and on shared-memory systems. In particular, such algorithms have the data reuse characteristics of a blocked algorithm that is simultaneously blocked at many different levels. Most existing applications, however, are written using ordinary loops. We present a new compiler

Qing Yi; Vikram S. Adve; Ken Kennedy

2000-01-01

85

Multi-level Partition of Unity Implicits  

E-print Network

inverse-distance singular weights. ·Nonnegative compactly supported set #12;Partition of Unity ·Blend-controlled approximation of signed distance function from surface. · Surface is zero-level of the distance function. #12 distance function: 0 near points, positive inside, negative outside. · If shape function isn't accurate

Kazhdan, Michael

86

Adaptive Multi-level Explicit Congestion Notification  

E-print Network

of the Internet [4]. Congestion remains the main obstacle to Quality of Serivce (QoS) on the Internet. Although and the level of congestion. This average queuing delay is a very importent for QoS applications. So setting the parameters of MECN is very importent and maintain a constant delay at the routers, is a must, to give any QoS

Jain, Raj

87

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

88

Cascaded Multi-Level Linear-Optical Quantum Router  

NASA Astrophysics Data System (ADS)

Quantum router is the requisite element in the future quantum network. In this paper, we describe an approach for constructing the cascaded multi-level quantum router, which is based on the previous work of Lemr et al. (Phys. Rev. A 87, 062333 (2013)). We show that the signals in the router output ports of the ith level can be regarded as the input signals of the (i + 1)th level. In this way, the cascaded multi-level quantum router can be constructed. We can obtain a K level quantum router with 2 K output ports. We also show that with the help of tunable c-phase gate, the success probability of the quantum router can be increased. Moreover, by exploiting the quantum nondemolition (QND) measurement, the control qubits can be reused to decrease the resource of the router. This protocol is useful for future quantum network.

Qu, Chang-Cheng; Zhou, Lan; Sheng, Yu-Bo

2015-01-01

89

Voltage Source Active Power Filter, Based on Multi-Stage Converter and Ultracapacitor DC-Link.  

E-print Network

Voltage Source Active Power Filter, Based on Multi-Stage Converter and Ultracapacitor DC, used for single phase inverters. These converters are able to produce three levels of voltage-41-246-999 e-mail lmoran@renoir.die.udec.cl Abstract. A multi-stage inverter using three-state converters

Catholic University of Chile (Universidad Católica de Chile)

90

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

E-print Network

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

Sussex, University of

91

A PORTABLE RUNTIME INTERFACE FOR MULTI-LEVEL MEMORY HIERARCHIES  

E-print Network

A PORTABLE RUNTIME INTERFACE FOR MULTI-LEVEL MEMORY HIERARCHIES A DISSERTATION SUBMITTED important challenges in program optimization. Moreover, efficient use of the memory hierarchy, a programming language we have developed at Stanford to facilitate the development of memory hierarchy aware

Pratt, Vaughan

92

Learning Dictionaries for Information Extraction by MultiLevel Bootstrapping  

Microsoft Academic Search

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

Ellen Riloff; Rosie Jones

1999-01-01

93

Original Article Using Europe: Strategic action in multi-level  

E-print Network

of the European political system. With its emphasis on the micro-foundations of personal motivations, trajectoriesOriginal Article Using Europe: Strategic action in multi-level politics Cornelia Woll* and Sophie. The recent turns towards constructivism and comparative political sociology allow analyzing the rationality

Paris-Sud XI, Université de

94

Multi-level Transformation from Conceptual Models to  

E-print Network

Chapter 1 Multi-level Transformation from Conceptual Models to Databases in ReMoDeL Ahmad F. Subahi of a sys- tem (merging) [1, 2]. Model transformation is defined as a process of converting one model.simons}@dcs.shef.ac.uk This chapter presents a framework for model transformation, organised around Java agents. Internally

Simons, Anthony J. H.

95

Priority Assignment Procedures in MultiLevel Assembly Job Shops  

Microsoft Academic Search

This paper deals with the design of priority rules for job shops that process multi-level assembly jobs. Specifically, it explores the means by which the structural complexity of jobs can be incorporated explicitly into priority rules to reduce job lead times. The job lead time is viewed as consisting of two components: flow time and job staging delays. The primary

Nabil R. Adam; J. Will M. Bertrand; Julius Surkis

1987-01-01

96

A Novel MultiLevel High Voltage Pulsed Power Generator  

Microsoft Academic Search

This paper presents a novel solid-state and high power pulse generation technique that is suitable for a wide range of pulsed power applications. The technique, termed as multi-level pulsed power converter, can be considered as a hybrid of the direct discharge type and the Marx generator but with considerably less complexity in both control and circuitry. It has the ability

D. J. Thrimawithana; U. K. Madawala

2007-01-01

97

Multi-Level Alert Clustering for Intrusion Detection Sensor Data*  

E-print Network

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

Siraj, Ambareen

98

PROCEEDINGS Open Access MKEM: a Multi-level Knowledge Emergence  

E-print Network

PROCEEDINGS Open Access MKEM: a Multi-level Knowledge Emergence Model for mining undiscovered Swanson proposed the Undiscovered Public Knowledge (UPK) model, there have been many approaches to uncover Language Processing techniques such as Link Grammar and Ontologies such as Unified Medical Language System

Lee, Doheon

99

The multi-level trigger system of the HADES detector  

Microsoft Academic Search

HADES is a second-generation di-electron spectrometer currently under commissioning at GSI Darmstadt. Its multi-level trigger system allows to select dilepton events in hadron- and heavy-ion induced reactions, leading to a suppression of events lacking lepton pairs by up to 4 orders of magnitude. The first level trigger is based on the charged particle multiplicity measured in a time-of-flight wall. The

I. Fröhlich; J. Lehnert; E. Lins; M. Petri; J. Ritman; M. Traxler; A. Toia

2002-01-01

100

Multi-level overlay techniques for improving DPL overlay control  

NASA Astrophysics Data System (ADS)

Overlay continues to be one of the key challenges for lithography in semiconductor manufacturing, especially in light of the accelerated pace of device node shrinks. This reality will be especially evident at 20nm node where DPL and multi-layer overlay will require 4nm or less in overlay control across many critical layers in order to meet device yield entitlements. The motivation for this paper is based on improving DPL overlay control in face of the high complexity involved with multi-layer overlay requirements. For example, the DPL-2nd-litho layer will need to achieve tight registration with the DPL-1st-litho layer, and at the same time, it will need to achieve tight overlay to the reference-litho layer, which in some cases can also be a DPL layer. Of course, multi-level overlay measurements are not new, but the combination of increased complexity of multi-DPL layers and extremely challenging overlay specifications for 20nm node together will necessitate a better understanding of multi-level overlay control, specifically in terms of root cause analysis of multi-layer related overlay errors and appropriate techniques for improvement In this paper, we start with the identification of specific overlay errors caused by multi-layer DPL processing on full film stack product wafers. After validation of these findings with inter-lot and intra-lot controlled experiments, we investigate different advanced control techniques to determine how to optimize overlay control and minimize both intra-lot and inter-lot sources of error. A new approach to overlay data analysis will also be introduced that combines empirical data with target image quality data to more accurately determine and better explain the root cause error mechanism as well as provide effective strategies for improved overlay control.

Chen, Charlie; Pai, Y. C.; Yu, Dennis; Pang, Peter; Yu, Chun Chi; Wu, Robert (Hsing-Chien); Huang, Eros (Chien Jen); Chen, Marson (Chiun-Chieh); Tien, David; Choi, Dongsub

2012-03-01

101

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

102

Multi-slot and multi-level coding technique over amplitude-shift keying modulation for optical communication links  

Microsoft Academic Search

A new multi-slot and multi-level coding technique, which is a combination of multiplexing and coding technique, known as Multi Slot Amplitude Coding (MSAC) is presented. This technique offers better flexibility in terms of defining the symbol based on time slot and signal level in order to generate more unique symbols as a line code with better clock information since all

R. Talib; M. F. L. Abdullah; A. Malekmohammadi; M. K. Abdullah

2011-01-01

103

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

104

Multi-level Hybrid Cache: Impact and Feasibility  

SciTech Connect

Storage class memories, including flash, has been attracting much attention as promising candidates fitting into in today's enterprise storage systems. In particular, since the cost and performance characteristics of flash are in-between those of DRAM and hard disks, it has been considered by many studies as an secondary caching layer underneath main memory cache. However, there has been a lack of studies of correlation and interdependency between DRAM and flash caching. This paper views this problem as a special form of multi-level caching, and tries to understand the benefits of this multi-level hybrid cache hierarchy. We reveal that significant costs could be saved by using Flash to reduce the size of DRAM cache, while maintaing the same performance. We also discuss design challenges of using flash in the caching hierarchy and present potential solutions.

Zhang, Zhe [ORNL; Kim, Youngjae [ORNL; Ma, Xiaosong [ORNL; Shipman, Galen M [ORNL; Zhou, Yuanyuan [University of California, San Diego

2012-02-01

105

Discrimination with jointly equicorrelated multi-level multivariate data  

Microsoft Academic Search

In this article we study a linear as well as a quadratic discriminant function for multi-level multivariate repeated measurement\\u000a data under the assumption of multivariate normality. We assume that the m-variate observations have jointly equicorrelated covariance structure in addition to a Kronecker product structure on the\\u000a mean vector. The new discriminant functions are very effective in discriminating individuals when the

Anuradha Roy; Ricardo Leiva

2007-01-01

106

Semantic modeling for multi-level medical image semantics retrieval  

Microsoft Academic Search

In this study, a multi-level medical image semantic modeling approach based on fuzzy Bayesian networks is proposed. Its two forms are built. The one is a Bayesian network embedding Conditional Gaussian (CG) models, called BN-CG, and another is a Bayesian network embedding Gaussian mixture model (GMM), called BN-GMM. CG and GMM are employed to implement a fuzzy procedure to perform

Chunyi Lin; Lihong Ma; Jianyu Chen

2010-01-01

107

On decoding of multi-level MPSK modulation codes  

NASA Technical Reports Server (NTRS)

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

Lin, Shu; Gupta, Alok Kumar

1990-01-01

108

On codes with multi-level error-correction capabilities  

NASA Technical Reports Server (NTRS)

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

Lin, Shu

1987-01-01

109

MultiLevel Organization for Learning A MultiLevel Organization of Semantic Primitives for Learning  

E-print Network

. Any agent that addresses the DAL task is confronted with a task of transforming the underlying causes explore the possibility of such a transformation through a hierarchical order of discretizations each. The machine learning research has identified formulation of environment models through multiple levels

Prabhakar, Sattiraju

110

A double-level-Vth select gate array architecture for multi-level NAND flash memories  

Microsoft Academic Search

This paper first explains that gate array noise during a bit-by-bit program verify operation, named source line noise, is estimated to have a crucial adverse effect on the threshold voltage (V th) control and causes a serious problem in Multi-Level NAND Flash Memories. Then a new array architecture, a Double-Level-Vth Select Gate Array Architecture, is introduced to eliminate this noise

K. Takeuchi; T. Tanaka; H. Nakamura

1995-01-01

111

The Importance of Proximal Fusion Level Selection for Outcomes of Multi-Level Lumbar Posterolateral Fusion  

PubMed Central

Background There are few studies about risk factors for poor outcomes from multi-level lumbar posterolateral fusion limited to three or four level lumbar posterolateral fusions. The purpose of this study was to analyze the outcomes of multi-level lumbar posterolateral fusion and to search for possible risk factors for poor surgical outcomes. Methods We retrospectively analyzed 37 consecutive patients who underwent multi-level lumbar or lumbosacral posterolateral fusion with posterior instrumentation. The outcomes were deemed either 'good' or 'bad' based on clinical and radiological results. Many demographic and radiological factors were analyzed to examine potential risk factors for poor outcomes. Student t-test, Fisher exact test, and the chi-square test were used based on the nature of the variables. Multiple logistic regression analysis was used to exclude confounding factors. Results Twenty cases showed a good outcome (group A, 54.1%) and 17 cases showed a bad outcome (group B, 45.9%). The overall fusion rate was 70.3%. The revision procedures (group A: 1/20, 5.0%; group B: 4/17, 23.5%), proximal fusion to L2 (group A: 5/20, 25.0%; group B: 10/17, 58.8%), and severity of stenosis (group A: 12/19, 63.3%; group B: 3/11, 27.3%) were adopted as possible related factors to the outcome in univariate analysis. Multiple logistic regression analysis revealed that only the proximal fusion level (superior instrumented vertebra, SIV) was a significant risk factor. The cases in which SIV was L2 showed inferior outcomes than those in which SIV was L3. The odds ratio was 6.562 (95% confidence interval, 1.259 to 34.203). Conclusions The overall outcome of multi-level lumbar or lumbosacral posterolateral fusion was not as high as we had hoped it would be. Whether the SIV was L2 or L3 was the only significant risk factor identified for poor outcomes in multi-level lumbar or lumbosacral posterolateral fusion in the current study. Thus, the authors recommend that proximal fusion levels be carefully determined when multi-level lumbar fusions are considered. PMID:25729522

Nam, Woo Dong

2015-01-01

112

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

113

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@et.aau.dk, ret@et.aau.dk) Keywords: Modular Multi-level Converters (MMC), Wind Power Plants (WPP), Voltage explores the application of modular multi-level converters (MMC) as a means for harnessing the power from

Chaudhary, Sanjay

114

Coercive Region-level Registration for Multi-modal Images  

E-print Network

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

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

2015-01-01

115

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

116

Union leadership and member attitudes: a multi-level analysis.  

PubMed

Analyses of union leadership roles show that union presidents should have both a within-union focus and an external focus. The authors combined multi-level survey data from 3,871 union members in 248 local teachers' unions with archival and field staff data to examine relationships between leadership and members' perceptions of union instrumentality and justice, union commitment, and participation. The results showed significant union-level effects on members' beliefs about, and attitudes toward, their unions, attributable to the presidents' internal and external leadership, wage outcomes, and union characteristics. Relationships between internally focused leadership and members' loyalty and willingness to work for the union were partially mediated by perceptions of union instrumentality and justice. These perceptions fully mediated the relationship between externally focused leadership and union loyalty. PMID:19271797

Hammer, Tove Helland; Bayazit, Mahmut; Wazeter, David L

2009-03-01

117

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

118

Multi-Level Analysis of Pulsed Detonation Engines  

NASA Technical Reports Server (NTRS)

The present study explores some issues concerning the operational performance of pulsed detonation engines. Zero-, one- and two-dimensional, transient models are employed in a synergistic manner to elucidate the various characteristics that can be expected from each level of analysis. The zero-dimensional model provides rapid parametric trends that help to identify the global characteristics of pulsed detonation engines. The one-dimensional model adds key wave propagation issues that are omitted in the zero-dimensional model and helps to assess its limitations. Finally, the two-dimensional model allows estimates of the first-order multi-dimensional effects and provides an initial multi-dimensional end-correction for the one-dimensional model. The zero-dimensional results indicate that the pulsed detonation engine is competitive with a rocket engine when exhausting to vacuum conditions. At finite back pressures, the PDE out-performs the rocket if the combustion pressure rise from the detonation is added to the chamber pressure in the rocket. If the two peak pressures are the same, the rocket performance is higher. Two-dimensional corrections added to the one-dimensional model result in a modest improvement in predicted specific impulse over the constant pressure boundary condition.

Ebrahimi, Houshang B.; Mohanraj, Rajendran; Merkle, Charles L.

2001-01-01

119

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

PubMed Central

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

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

2010-01-01

120

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

NASA Technical Reports Server (NTRS)

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

1980-01-01

121

Multi-Level Barriers to LTBI Treatment: A Research Note  

PubMed Central

Background This study describes the barriers to effective and timely LTBI treatment encountered in a research study on INH adherence in Latino adolescents. Method Participant study logs were reviewed, results of continuing medical education pretests for medical providers were examined, and participating medical facilities were contacted in order to construct a profile of multi-level barriers to LTBI treatment. Results A total of 285 TST positive Latino (96%) high school students were recruited into the trial. We encountered a lack of understanding of the gravity of tuberculosis infection among both the public and providers of health care. Parents and adolescents cited competing priorities, transportation problems and financial constraints as reasons for non-compliance. Discussion Improved education of the public and physicians is needed regarding the gravity of the disease and the value of treatment, as well as public and financial support for LTBI treatment by both the government and the medical community. PMID:19085104

Blumberg, Elaine; Sipan, Carol; Schmitz, Katharine; West, Joshua; Kelley, Norma; Hovell, Melbourne

2008-01-01

122

Biomechanics of actin filaments: a computational multi-level study.  

PubMed

The actin microfilament (F-actin) is a structural and functional component of the cell cytoskeleton. Notwithstanding the primary role it plays for the mechanics of the cell, the mechanical behaviour of F-actin is still not totally explored. In particular, the relationship between the mechanics of F-actin and its molecular architecture is not completely understood. In this study, the mechanical properties of F-actin were related to the molecular topology of its building monomers (G-actin) by employing a computational multi-level approach. F-actins with lengths up to 500 nm were modelled and characterized, using a combination of equilibrium molecular dynamics (MD) simulations and normal mode analysis (NMA). MD simulations were performed to analyze the molecular rearrangements of G-actin in physiological conditions; NMA was applied to compute the macroscopic properties of F-actin from its vibrational modes of motion. Results from this multi-level approach showed that bending stiffness, bending modulus and persistence length are independent from the length of F-actin. On the contrary, the orientations and motions of selected groups of residues of G-actin play a primary role in determining the filament flexibility. In conclusion, this study (i) demonstrated that a combined computational approach of MD and NMA allows to investigate the biomechanics of F-actin taking into account the molecular topology of the filament (i.e., the molecular conformations of G-actin) and (ii) that this can be done using only crystallographic G-actin, without the need of introducing experimental parameters nor of reducing the number of residues. PMID:21130998

Deriu, Marco A; Bidone, Tamara C; Mastrangelo, Francesco; Di Benedetto, Giacomo; Soncini, Monica; Montevecchi, Franco M; Morbiducci, Umberto

2011-02-24

123

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

PubMed

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

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

2013-01-01

124

Monitoring the nociception level: a multi-parameter approach.  

PubMed

The aim of the present study was to develop and validate an objective index for nociception level (NoL) of patients under general anesthesia, based on a combination of multiple physiological parameters. Twenty-five patients scheduled for elective surgery were enrolled. For clinical reference of NoL, the combined index of stimulus and analgesia was defined as a composite of the surgical stimulus level and a scaled effect-site concentration of opioid. The physiological parameters heart rate, heart rate variability (0.15-0.4 Hz band power), plethysmograph wave amplitude, skin conductance level, number of skin conductance fluctuations, and their time derivatives, were extracted. Two techniques to incorporate these parameters into a single index representing the NoL have been proposed: NoLlinear, based on an ordinary linear regression, and NoLnon-linear, based on a non-linear Random Forest regression. NoLlinear and NoLnon-linear significantly increased after moderate to severe noxious stimuli (Wilcoxon rank test, p < 0.01), while the individual parameters only partially responded. Receiver operating curve analysis showed that NoL index based on both techniques better discriminated noxious and non-noxious surgical events [area under curve (AUC) = 0.97] compared with individual parameters (AUC = 0.56-0.74). NoLnon-linear better ranked the level of nociception compared with NoLlinear (R = 0.88 vs. 0.77, p < 0.01). These results demonstrate the superiority of multi-parametric approach over any individual parameter in the evaluation of nociceptive response. In addition, advanced non-linear technique may have an advantage over ordinary linear regression for computing NoL index. Further research will define the usability of the NoL index as a clinical tool to assess the level of nociception during general anesthesia. PMID:23835792

Ben-Israel, Nir; Kliger, Mark; Zuckerman, Galit; Katz, Yeshayahu; Edry, Ruth

2013-12-01

125

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

126

Hybrid Cascaded Multilevel Inverter with PWM Control Method  

E-print Network

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

Tolbert, Leon M.

127

Challenge of multi-level governance in developing countries and possible GIS applications  

Microsoft Academic Search

Of the three most prominent issues in governance discourse—the horizontal coordination of markets, government hierarchies and networks, global governance and multi-level governance—this paper argues that the last, developing and sustaining structures of multi-level governance, constitutes the most profound governance challenge for most developing countries.The paper identifies the major forces promoting change in favor of multi-level governance in developing countries. Using

Dele Olowu

2003-01-01

128

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

Microsoft Academic Search

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

Masatoshi Sakawa; Ichiro Nishizaki; Yoshio Uemura

2000-01-01

129

Multi-Level Modeling of Dyadic Data in Sport Sciences: Conceptual, Statistical, and Practical Issues  

ERIC Educational Resources Information Center

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…

Gaudreau, Patrick; Fecteau, Marie-Claude; Perreault, Stephane

2010-01-01

130

System Level Methodology for Programming CMP based Multi-threaded Network Processor Architectures  

E-print Network

System Level Methodology for Programming CMP based Multi-threaded Network Processor Architectures led to the advent of chip multi-processor (CMP) based multi-threaded network processor (NP) architectures. The CMP based architectures include a multitude of heteroge- neous memory units ranging from on

Chatha, Karam S.

131

Multi-level recordable disc using signal waveform modulation recording method  

NASA Astrophysics Data System (ADS)

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

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

132

Control techniques for multilevel voltage source inverters  

Microsoft Academic Search

A multilevel inverter is a power electronic device built to synthesize a desired AC voltage from several levels of DC voltages. Recent advances in power electronics have made the multilevel concept practical. In fact, the concept is so advantageous that several major drives manufacturers have obtained recent patents on multilevel power converters and associated switching techniques. Multilevel inverters have been

V. K. Chinnaiyan; J. Jerome; J. Karpagam; T. Suresh

2007-01-01

133

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

NASA Astrophysics Data System (ADS)

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

Kathalingam, Sebasthi Rani; Karantharaj, Porkumaran

2012-07-01

134

Physics of Polarized Scattering at Multi-level Atomic Systems  

NASA Astrophysics Data System (ADS)

The symmetric peak observed in linear polarization in the core of the solar sodium D1 line at 5896 Å 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 D1 enigma is a problem of solar physics or quantum physics revealed that the D1 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. Radiative couplings between the allowed dipole transitions generate coherences in the initial state. Corresponding coherences in the final state are then demanded by a phase closure selection rule. The experimental results for the well understood D2 line are used to constrain the two free parameters of the experiment, collision rate and optical depth, to suppress the need for free parameters when fitting the D1 results.

Stenflo, J. O.

2015-03-01

135

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

136

Design of a Multi-Level/Analog Ferroelectric Memory Device  

NASA Technical Reports Server (NTRS)

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

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

2006-01-01

137

Recognising interdependence and defining multi-level governance in city sustainability plans  

Microsoft Academic Search

A growing number of city governments in the USA have developed plans to pursue sustainable development and mitigate climate change. City governments do not act alone on such complex environmental and social policies, but participate in a web of multi-level governance relationships, interacting with other local governments, community organisations, state and federal government agencies, and international organisations. How is multi-level

Eric Zeemering

2012-01-01

138

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

E-print Network

in Copper CMP Direct Overlap: Structure Metal 1 Metal 2 Oxide Oxide M1 Bottom Pad M1 Top Pad M2 Top Pad M2T. 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

Boning, Duane S.

139

A high speed programming scheme for multi-level NAND flash memory  

Microsoft Academic Search

A new scheme for page programming of multi-level NAND flash memory has been developed. It maintains the 528 byte page size of 32 Mb NAND flash memories with a high throughput of 0.5 MB\\/s. The circuitry has been successfully implemented into an experimental 128 Mb multi-level flash memory

Young-Joon Choi; Kang-Deog Suh; Yong-Nam Koh; Jong-Wook Park; Ki-Jong Lee; Yun-Jin Cho; Byung-Hoon Suh

1996-01-01

140

Antibiotic resistance shaping multi-level population biology of bacteria  

PubMed Central

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

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

2013-01-01

141

A multi-level fast multipole BEM for 3-D elastodynamics in the frequency domain  

Microsoft Academic Search

To reduce computational complexity and memory requirement for 3-D elastodynamics using the boundary element method (BEM), a multi-level fast multipole BEM (FM-BEM) is proposed. The diagonal form for the expansion of the elastodynamic fundamental solution is used, with a truncation parameter adjusted to the subdivision level, a feature necessary for achieving optimal computational efficiency. Both the single-level and multi-level forms

Stéphanie Chaillat; Marc Bonnet; Jean-François Semblat

2008-01-01

142

Grief recovery from the loss of a family business: A multi- and meso-level theory  

Microsoft Academic Search

In this article I develop a multi- and meso-level theory of grief recovery time from the loss of a family business. The multi-level aspect of the model suggests how primarily micro theories of grief and sense-making can help explain grief recovery time at the family group level. The meso-level aspect of the model provides insight into recovery from the loss

Dean A. Shepherd

2009-01-01

143

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

144

Multi-system, multi-signal GNSS-reflectometry for sea level observations  

NASA Astrophysics Data System (ADS)

Information on sea level and its changes are important in connection to global change processes. For centuries sea level has been observed with coastal tide gauges and since some decades with satellite altimetry. Furthermore, during recent years also the application of GNSS-reflectometry for sea level observations has been developed. Various methods exist, using ground-based, airborne and space-borne systems, and using different analysis methods. We present results from a dedicated GNSS-based tide gauge installed at the Onsala Space Observatory at the Swedish west coast. This installation consists of two sets of commercially-off-the-shelf GNSS equipment, including geodetic-type choke-ring antennae and geodetic-type receivers. The two antennae are mounted on a beam extending in southward direction over the coastline. The antennae are aligned along the local vertical with one antenna facing toward zenith direction and the other facing toward nadir. The zenith-looking antenna is Right-Hand-Circular-Polarised (RHCP) while the nadir-looking antenna is Left-Hand-Circular-Polarised (LHCP). The zenith-looking antenna receives predominantly the direct RHCP satellite signals, while the nadir-looking antenna receives predominantly signals that are reflected off the sea surface and thus have changed polarisation to LHCP in the reflection process. The GNSS-receivers are connected to one antenna each and individually record multi-frequency signals of several GNSS. The recorded data can be analysed in different ways to derive information on the sea level and its variation. For example, data from both receivers can be analysed together applying geodetic-type phase-delay analysis with a single-difference and/or double-difference strategy. These analysis methods determine the baseline between the two antennae, which is proportional to the height of the installation above the sea surface. Another analysis method exploits the multipath oscillations in the recorded Signal-to-Noise Ratio (SNR) data observed with the zenith-looking antenna/receiver to determine the distance between the sea surface and the antenna. The different approaches have advantages and disadvantages, and they can be combined with standard positioning of the zenith-looking antenna to give absolute sea level information. In the presentation we describe the installation, the analysis methods and present the corresponding results. The focus is in particular on GPS and GLONASS observations in both L-band frequency bands, and the result obtained are from the different analysis approaches are compared with independently derived sea level observations from a co-located traditional tide gauge. Our results show that GPS and GLONASS phase-delay analysis method using signals in the L1 and L2 frequency bands gives a root-mean-square (RMS) agreement on the order of 3-4 cm when compared to independently observed sea level data. The corresponding results derived from the SNR-analysis method are worse by a factor of about 1.5 and 3 for the L1 and L2 frequency bands, respectively. However, the SNR-method appears to have advantages in conditions of high sea surface roughness. References: Löfgren J, Haas R, Scherneck H-G, Bos M (2011) Three months of local sea level derived from reflected GNSS signals. Radio Science, 46 (RS0C05) Larson K, Löfgren J, Haas R (2013) Coastal Sea Level Measurements Using a Single Geodetic GPS Receiver. Advances in Space Research, 51 (8) pp. 1301-1310.

Löfgren, Johan; Haas, Rüdiger

2014-05-01

145

Parallel operation control technique of voltage source inverters in UPS  

Microsoft Academic Search

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

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

1999-01-01

146

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

147

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

148

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

E-print Network

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

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

1999-06-14

149

Real-Time Systems Performance Improvement with MultiLevel Cache Memory  

Microsoft Academic Search

Cache memory is known to be of great significance for system performance. One of the most important performance attributes of modern computing systems is speed. The current article presents and explores a technique applied to multi-level cache memory to reduce contention in a multi-tasking environment and at the same time to increase predictability and speed. Because of its unpredictable behavior,

Hyacinthe Aboudja; Jonathan Simonson

2006-01-01

150

Song-level Multi-pitch Tracking by Heavily Constrained Clustering  

E-print Network

Song-level Multi-pitch Tracking by Heavily Constrained Clustering Zhiyao Duan, Jinyu Han and Bryan://music.cs.northwestern.edu For presentation in ICASSP 2010, Dallas, Texas, USA. #12;Multi-pitch Estimation & Tracking Task · Given polyphonic music played by several monophonic harmonic instruments (Num known) · Estimate a pitch trajectory

Pardo, Bryan

151

A multi-level computational model for multi-scale damage analysis in composite and porous materials  

Microsoft Academic Search

An adaptive multi-level methodology is developed in this paper to create a hierarchy of computational sub-domains with varying resolution for multiple scale problems. It is intended to concurrently predict evolution of variables at the structural and microstructural scales, as well as to track the incidence and propagation of microstructural damage in composite and porous materials. The microstructural analysis is conducted

Somnath Ghosh; Kyunghoon Lee; Prasanna Raghavan

2001-01-01

152

Switching Characteristics of Ferroelectric Transistor Inverters  

NASA Technical Reports Server (NTRS)

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

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

2010-01-01

153

Making the most of clustered data in laboratory animal research using multi-level models.  

PubMed

In the following review article, I address the fitting of multi-level models for the analysis of hierarchical data in laboratory animal medicine. Using an example of paternal dietary effects on the weight of offspring in a mouse model, this review outlines the reasons and benefits of using a multi-level modeling approach. To start, the concept of clustered/autocorrelated data is introduced, and the implications of ignoring the effects of clustered data on measures of association/model coefficients and their statistical significance are discussed. The limitations of other methods compared with multi-level modeling for analyzing clustered data are addressed in terms of statistical power, control of potential confounding effects associated with group membership, proper estimation of associations and their statistical significance, and adjusting for multiple levels of clustering. In addition, the benefits of being able to estimate variance partition coefficients and intra-class correlation coefficients from multi-level models is described, and the concepts of more complex correlation structures and various methods for fitting multi-level models are introduced. The current state of learning materials including textbooks, websites, and software for the nonstatistician is outlined to describe the accessibility of multi-level modeling approaches for laboratory animal researchers. PMID:25541550

Pearl, David L

2014-01-01

154

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

E-print Network

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

Lewinski, Christi Nicole

2007-09-17

155

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...

156

PWM current controller design for multi-level DC-DC converter via singular perturbation technique  

Microsoft Academic Search

The problem of current regulation for a multi- level DC-DC converter is discussed. The paper addresses PI control with an additional low-pass filtering and a high- frequency pulse-width modulation (PWM) in control loop. The problem of controller design is reduced to the continu- ous-time controller design based on the Filippov's average model of the multi-level DC-DC converter. The design meth-

Valery D. Yurkevich; Gennady S. Zinoviev; Artem A. Gordeev

2011-01-01

157

Pruned multi-level successive elimination algorithm for TV commercial recognition  

Microsoft Academic Search

In this paper, an efficient duplicate matching algorithm, called pruned multi-level successive elimination (PMSE), is proposed for TV commercial recognition. To enhance the efficiency of filtering out the irrelevant candidates from a sizable database, a felicitous pruning strategy is adapted to the multi-level successive elimination by exploiting the similarity relations of all candidates that can be constructed off-line. By progressively

Houde Yang; Nan Liu; Yao Zhao; Zhenfeng Zhu

2011-01-01

158

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

Microsoft Academic Search

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

Maria Seniorou; Nicky Thompson; Marian Harrington; Tim Theologis

2007-01-01

159

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

160

A development of experimental education program: computer control of multi-stage level control system  

Microsoft Academic Search

We developed an experimental education program and the apparatus with computer software for chemical process control. A multi-stage liquid level control system is chosen as a target process because it is one of the simplest chemical processes to understand. The target process is composed of one storage tank, two series liquid level tanks and one more interactive liquid level tank

Jae Hak Jung; Moonyong Lee; Lee Jietae; Chonghun Han

2000-01-01

161

Rule-based multi-level modeling of cell biological systems  

PubMed Central

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

2011-01-01

162

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

163

Novel multilevel inverter carrier-based PWM method  

SciTech Connect

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

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

1999-10-01

164

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

165

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

166

a Decision Level Fusion Method for Object Recognition Using Multi-Angular Imagery  

NASA Astrophysics Data System (ADS)

Spectral similarity and spatial adjacency between various kinds of objects, shadow and occluded areas behind high rise objects as well as complex relationships lead to object recognition difficulties and ambiguities in complex urban areas. Using new multi-angular satellite imagery, higher levels of analysis and developing a context aware system may improve object recognition results in these situations. In this paper, the capability of multi-angular satellite imagery is used in order to solve object recognition difficulties in complex urban areas based on decision level fusion of Object Based Image Analysis (OBIA). The proposed methodology has two main stages. In the first stage, object based image analysis is performed independently on each of the multi-angular images. Then, in the second stage, the initial classified regions of each individual multi-angular image are fused through a decision level fusion based on the definition of scene context. Evaluation of the capabilities of the proposed methodology is performed on multi-angular WorldView-2 satellite imagery over Rio de Janeiro (Brazil).The obtained results represent several advantages of multi-angular imagery with respect to a single shot dataset. Together with the capabilities of the proposed decision level fusion method, most of the object recognition difficulties and ambiguities are decreased and the overall accuracy and the kappa values are improved.

Tabib Mahmoudi, F.; Samadzadegan, F.; Reinartz, P.

2013-09-01

167

Extreme multi-level anterior cervical discectomy and fusion.  

PubMed

The use of anterior cervical discectomy and fusion (ACDF) is a common procedure used to treat those who suffer from degenerative disc disease (DDD) of the cervical spine which may result in spondylolisthesis, spinal stenosis, disc herniation, nerve root and/or cord compression. ACDF is regularly used for the fusion of one to four cervical spine levels; however, the literature documenting the fusion of 5 or 6 levels is surprisingly lacking. In this retrospective review of our case series, we document two 5-level and two 6-level ACDF in elderly patients using custom made titanium fusion plates and patellar allograft bone for interbody placement without posterior fixation. The documentation of these long anterior constructs without supplemental posterior fixation or the use of a halo vest apparatus, but a simple neck collar for three months, is an important contribution to the literature illustrating that with utilization of appropriate technique, a high number of levels can be safely fused in the elderly patients necessitating this particular procedure. PMID:23957113

Morgan, Jeremy P; Asfora, Wilson T

2013-07-01

168

Multi -risk assessment at a national level in Georgia  

NASA Astrophysics Data System (ADS)

Work presented here was initiated by national GNSF project " Reducing natural disasters multiple risk: a positive factor for Georgia development " and two international projects: NATO SFP 983038 "Seismic hazard and Rusk assessment for Southern Caucasus-eastern Turkey Energy Corridors" and EMME " Earthquake Model for Middle east Region". Methodology for estimation of "general" vulnerability, hazards and multiple risk to natural hazards (namely, earthquakes, landslides, snow avalanches, flash floods, mudflows, drought, hurricanes, frost, hail) where developed for Georgia. The electronic detailed databases of natural disasters were created. These databases contain the parameters of hazardous phenomena that caused natural disasters. The magnitude and intensity scale of the mentioned disasters are reviewed and the new magnitude and intensity scales are suggested for disasters for which the corresponding formalization is not yet performed. The associated economic losses were evaluated and presented in monetary terms for these hazards. Based on the hazard inventory, an approach was developed that allowed for the calculation of an overall vulnerability value for each individual hazard type, using the Gross Domestic Product per unit area (applied to population) as the indicator for elements at risk exposed. The correlation between estimated economic losses, physical exposure and the magnitude for each of the six types of hazards has been investigated in detail by using multiple linear regression analysis. Economic losses for all past events and historical vulnerability were estimated. Finally, the spatial distribution of general vulnerability was assessed, and the expected maximum economic loss was calculated as well as a multi-risk map was set-up.

Tsereteli, Nino; Varazanashvili, Otar; Amiranashvili, Avtandil; Tsereteli, Emili; Elizbarashvili, Elizbar; Saluqvadze, Manana; Dolodze, Jemal

2013-04-01

169

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

ERIC Educational Resources Information Center

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

Mayhew, Matthew J.

2012-01-01

170

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

E-print Network

Programs Management, Supply Chain, Budget/COA, and Monthly Financial. This report can be run by ManagerGL074 Financial Summary with Management Level & Project Purpose (Excluding Agency and Multi with Management Level & Project Purpose © 2010 Northwestern University Page 1 of 3 This job aid explains some

Shull, Kenneth R.

171

A Multi-level Transformation from Conceptual Data Models to Database Scripts using Java Agents  

E-print Network

A Multi-level Transformation from Conceptual Data Models to Database Scripts using Java Agents transformation is defined as a process of converting one model into another using transformation rules acting on models at different levels of abstraction [3, 4]. A goal is to identify modular and reusable

Simons, Anthony J. H.

172

Towards Multi-application Workload Modeling in Sesame for System-level Design Space Exploration  

E-print Network

Towards Multi-application Workload Modeling in Sesame for System-level Design Space Exploration and simulation framework aims at early and thus efficient system-level design space exploration of embedded design space exploration. Such early design space exploration is of eminent importance as early design

Pimentel, Andy D.

173

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

174

MULTI-LEVEL PATTERN EFFECTS IN COPPER CMP Tae Park, Tamba Tugbawa, Duane Boning,  

E-print Network

MULTI-LEVEL PATTERN EFFECTS IN COPPER CMP Tae Park, Tamba Tugbawa, Duane Boning, *Steve Hymes, *Tom structures. The test vehicle used is a set of two level (metal 1 and metal 2) masks with electrical bond pads overlap cases including direct, half, dual, and cross overlaps. CMP polished surface profiles

Boning, Duane S.

175

Collaborative systems development in disaster relief: The impact of multi-level governance  

Microsoft Academic Search

Disaster management information systems for international humanitarian relief are developed in contexts involving local, national\\u000a and inter-governmental organizations together with local and international non-governmental organizations (NGOs). While the\\u000a multi-organizational nature of disaster response is known to create challenges for information systems development, to date,\\u000a less attention has been paid to their multi-level nature. This research sheds light on the implications

Edgar A. Maldonado; Carleen F. Maitland; Andrea Hoplight Tapia

2010-01-01

176

MultiLevel Parallelism for the Cardiac Bidomain Equations  

Microsoft Academic Search

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

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

2009-01-01

177

Embedding secret information into a dithered multi-level image  

Microsoft Academic Search

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

Kiyoshi TANAKA; Yasuhiro NAKAMURA; Kineo MATSUI

1990-01-01

178

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

PubMed

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

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

2013-01-01

179

Multi-level manual and autonomous control superposition for intelligent telerobot  

NASA Technical Reports Server (NTRS)

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

Hirai, Shigeoki; Sato, T.

1989-01-01

180

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

NASA Astrophysics Data System (ADS)

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

Shao, Meng; Pei, Jing; Yang, Bo

2013-12-01

181

Synchronized overmodulation techniques for the neutral-clamped inverters  

Microsoft Academic Search

The paper presents detailed analysis of the synchronized overmodulation control modes for three-level neutral-clamped inverters with control algorithms which eliminate the common-mode voltages. Two basic versions of discontinuous pulsewidth modulation (PWM) for control of inverters in the zone of overmodulation have been analysed in the paper. The spectra of the output voltage of inverters do not contain even harmonics and

V. Oleschuk; B. K. Bose; Zhe Chen

2003-01-01

182

Multi-level arc combination with stochastic parameters  

NASA Astrophysics Data System (ADS)

The method of square root information filtering and smoothing (SRIF/S) is reviewed and has been implemented in the combined square root information filter and smoother (CSRIFS) program. CSRIFS is a part of the GEOSAT space geodesy software developed at Forsvarets forskningsinstitutt (FFI, The Norwegian Defence Research Establishment). The state vectors and complete variance-covariance matrices from the analyses of a number of independent arcs of space geodesy data can be combined using CSRIFS. Four parameter levels are available and any parameter can, at each level, be represented as either a constant or a stochastic parameter (white noise, colored noise, or random walk). The batch length (i.e. the time interval between the addition of noise to the SRIF array) can be made time and parameter dependent. CSRIFS was applied in the combination of 623 very long baseline interferometry (VLBI) observing sessions. The purpose of this test was to validate the computer implementation of the SRIF/S method and to give an example of how this method can be used in the analysis of a large number of space geodetic observations. The results show that the implementation is very satisfactory.

Andersen, P. H.

2000-11-01

183

Squeezed light from multi-level closed-cycling atomic systems  

NASA Technical Reports Server (NTRS)

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

Xiao, Min; Zhu, Yi-Fu

1994-01-01

184

Fabrication and characterization of multi-level hierarchical surfaces.  

PubMed

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

Bhushan, Bharat; Lee, Hyungoo

2012-01-01

185

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

186

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

NASA Technical Reports Server (NTRS)

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

Horton, Graham; Leutenegger, Scott T.

1993-01-01

187

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

E-print Network

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

Atsushi Noguchi; Kenji Toyoda; Shinji Urabe

2012-09-05

188

Energy Efficient Multi-Level Clustering To Prolong The Lifetime of Wireless Sensor Networks  

E-print Network

Clustering in wireless sensor networks (WSNs) is an important technique to ease topology management and routing. Clustering provides an effective method for prolonging lifetime of a WSN. This paper proposes energy efficient multi-level clustering schemes for wireless sensor networks. Wireless sensor nodes are extremely energy constrained with a limited transmission range. Due to large area of deployment, the network needs to have a multi-level clustering protocol that will enable far-off nodes to communicate with the base station. Simulation is used to analyze the proposed protocols and compare their performance with existing protocol EEMC. Simulation results demonstrate that our proposed protocols are effective in prolonging the network lifetime.

Soni, Surender

2010-01-01

189

Multi-level hot zone identification for pedestrian safety.  

PubMed

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

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

2015-03-01

190

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

E-print Network

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

191

Deformation-induced inverted metamorphic eld gradients: an example from the southeastern Canadian Cordillera  

E-print Network

Deformation-induced inverted metamorphic ®eld gradients: an example from the southeastern Canadian analysis of diachronous metamorphism and associated deformation. At the deepest exposed level allochthon and Monashee complex, exhibits an inverted metamorphic ®eld gradient. New data presented

Gibson, Dan

192

SONG-LEVEL MULTI-PITCH TRACKING BY HEAVILY CONSTRAINED CLUSTERING Zhiyao Duan, Jinyu Han and Bryan Pardo  

E-print Network

SONG-LEVEL MULTI-PITCH TRACKING BY HEAVILY CONSTRAINED CLUSTERING Zhiyao Duan, Jinyu Han and Bryan voices or wind instruments), multi-pitch estimation (MPE) is the task of determining the instantaneous pitches of each source. Multi-pitch tracking (MPT) connects the instantaneous pitch estimates provided

Pardo, Bryan

193

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

194

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

195

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

196

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

197

Multi-level model for the investigation of oncoantigen-driven vaccination effect  

PubMed Central

Background Cancer stem cell theory suggests that cancers are derived by a population of cells named Cancer Stem Cells (CSCs) that are involved in the growth and in the progression of tumors, and lead to a hierarchical structure characterized by differentiated cell population. This cell heterogeneity affects the choice of cancer therapies, since many current cancer treatments have limited or no impact at all on CSC population, while they reveal a positive effect on the differentiated cell populations. Results In this paper we investigated the effect of vaccination on a cancer hierarchical structure through a multi-level model representing both population and molecular aspects. The population level is modeled by a system of Ordinary Differential Equations (ODEs) describing the cancer population's dynamics. The molecular level is modeled using the Petri Net (PN) formalism to detail part of the proliferation pathway. Moreover, we propose a new methodology which exploits the temporal behavior derived from the molecular level to parameterize the ODE system modeling populations. Using this multi-level model we studied the ErbB2-driven vaccination effect in breast cancer. Conclusions We propose a multi-level model that describes the inter-dependencies between population and genetic levels, and that can be efficiently used to estimate the efficacy of drug and vaccine therapies in cancer models, given the availability of molecular data on the cancer driving force. PMID:23734974

2013-01-01

198

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

PubMed

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

Omar, R Z; Thompson, S G

2000-10-15

199

A multi-band, multi-level, multi-electron model for efficient FDTD simulations of electromagnetic interactions with semiconductor quantum wells  

E-print Network

We report a new computational model for simulations of electromagnetic interactions with semiconductor quantum well(s) (SQW) in complex electromagnetic geometries using the finite difference time domain (FDTD) method. The presented model is based on an approach of spanning a large number of electron transverse momentum states in each SQW sub-band (multi-band) with a small number of discrete multi-electron states (multi-level, multi-electron). This enables accurate and efficient two dimensional (2-D) and 3-D simulations of nanophotonic devices with SQW active media. The model includes the following features: (1) Optically induced interband transitions between various SQW conduction and heavy-hole or light-hole sub-bands are considered. (2) Novel intra sub-band and inter sub-band transition terms are derived to thermalize the electron and hole occupational distributions to the correct Fermi-Dirac distributions. (3) The terms in (2) result in an explicit update scheme which circumvents numerically cumbersome ite...

Ravi, Koustuban; Ho, Seng-Tiong

2015-01-01

200

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

201

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

202

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

E-print Network

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

Bruck, Jehoshua (Shuki)

203

Multi-level surface enhanced Raman scattering using AgOx thin film  

E-print Network

, F. Tam, and N. J. Halas, "Surface-enhanced Raman spectroscopy of DNA," J. Am. Chem. Soc. 130Multi-level surface enhanced Raman scattering using AgOx thin film Ming Lun Tseng,1,2 Chia Min@phys.ntu.edu.tw Abstract: Ag nanostructures with surface-enhanced Raman scattering (SERS) activities have been fabricated

Leung, Pui-Tak "Peter"

204

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

Microsoft Academic Search

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

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

2010-01-01

205

Statistical Methods in Medical Research 2006; 15: 4761 Multi-level zero-inflated Poisson regression  

E-print Network

Statistical Methods in Medical Research 2006; 15: 47­61 Multi-level zero-inflated Poisson of such data is to use a zero-inflated Poisson (ZIP) regression model. Often, because of the hierarchical study design or the data collection procedure, zero-inflation and lack of independence may occur simultaneously

McLachlan, Geoff

206

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

207

PROPORTION OF MODERATELY EXERCISING INDIVIDUALS RESPONDING TO LOW-LEVEL, MULTI-HOUR OZONE EXPOSURE  

EPA Science Inventory

The purpose of this study was to describe the proportion of moderately exercising individuals experiencing significant respiratory responses to low-level, multi-hour ozone exposure as a function of ozone concentration and exposure duration. ixty-eight healthy, nonsmoking adults, ...

208

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

E-print Network

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

Wachs, Juan

209

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

210

Multi-Level Direction of Autonomous Creatures for Real-Time Virtual Environments  

E-print Network

Multi-Level Direction of Autonomous Creatures for Real-Time Virtual Environments Bruce M. Blumberg-based autonomous creatures. While competent autonomous action is highly desirable, there is an important need animated creatures for interactive virtual environ- ments which are also capable of being directed

211

MultiLevel Direction of Autonomous Creatures for RealTime Virtual Environments  

E-print Network

Multi­Level Direction of Autonomous Creatures for Real­Time Virtual Environments Bruce M. Blumberg­based autonomous creatures. While competent autonomous action is highly desirable, there is an important need animated creatures for interactive virtual environ­ ments which are also capable of being directed

Pratt, Vaughan

212

Simulation of Multi-Robot Teams with Flexible Level of Detail  

E-print Network

robots equipped with cameras and laser scanners. In this paper the core functionalities of Mu- lation of laser scanners are presented. The performance of these features is tested in an urban scenario experiment. For example, a high level of detail in robot motion simulation using multi-body dynamics

Stryk, Oskar von

213

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

214

A Study On Optimal Hierarchy in Multi-Level Hierarchical Mobile IPv6 Networks  

E-print Network

A Study On Optimal Hierarchy in Multi-Level Hierarchical Mobile IPv6 Networks Sangheon Pack, Minji, Korea Email: {shpack, mjnam}@mmlab.snu.ac.kr and yhchoi@snu.ac.kr Abstract-- Hierarchical Mobile IPv6 (HMIPv6) is an enhanced Mobile IPv6 in order to reduce signaling overhead and to support seamless handoff

215

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...

216

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

Microsoft Academic Search

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

Sumita Ketkar; P. K. Sett

2009-01-01

217

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

E-print Network

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

Grujicic, Mica

218

Multi-Level Research on Youth Participation in the Haitian Reconstruction  

ERIC Educational Resources Information Center

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

Pluim, Gary W. J.

2012-01-01

219

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

E-print Network

over policy, mitigation strategies and capacity for adaptation to climate change require construction integrated regional policies for climate change aware sustainable development can be achieved through for future research. Key words Multi-level, climate change, participatory process, decision-making, water

Paris-Sud XI, Université de

220

Training Data Recycling for Multi-Level Learning Jingchen Liu1  

E-print Network

Training Data Recycling for Multi-Level Learning Jingchen Liu1 , Scott McCloskey2 , Yanxi Liu1 1 consequences. By recycling the knowledge obtained during the base-classifier-training stage, we make the most-fitting. While cross-validation can provide similar benefits in some cases, generating balanced partitions

221

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

222

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

E-print Network

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

Skubic, Marjorie

223

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

224

Error correction for multi-level NAND flash memory using Reed-Solomon codes  

Microsoft Academic Search

Prior research efforts have been focusing on using BCH codes for error correction in multi-level cell (MLC) NAND flash memory. However, BCH codes often require highly parallel implementations to meet the throughput requirement. As a result, large area is needed. In this paper, we propose to use Reed-Solomon (RS) codes for error correction in MLC flash memory. A (828, 820)

Bainan Chen; Xinmiao Zhang; Zhongfeng Wang

2008-01-01

225

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

Microsoft Academic Search

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

Stephen A. Ehmann; Ming C. Lin

2000-01-01

226

Understanding multi-level institutional convergence effects on international market segments and global marketing strategy  

Microsoft Academic Search

Dynamic changes in the global marketplace have increased opportunities for marketing strategy standardization due to the convergence of cross-national market segments. An oversimplified understanding of the complexities of this convergence could lead to ineffective global marketing strategy execution. This study develops a multi-level institutional approach to address level-based convergence effects necessary to understanding market segment convergence and its influence on

David A. Griffith

2010-01-01

227

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

228

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

229

Hybrid Multilevel Inverter with Single DC Haiwen Liu1  

E-print Network

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

Tolbert, Leon M.

230

Parallel operation of voltage source inverters with minimal intermodule reactors  

Microsoft Academic Search

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

Bin Shi; Giri Venkataramanan

2004-01-01

231

Invert emulsion well servicing fluids  

Microsoft Academic Search

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

Carnicom

1982-01-01

232

Invertibility of irreducible matrices  

Microsoft Academic Search

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

Shangjun Yang; Xiaodong Zhang

1997-01-01

233

Inverting the Achievement Pyramid  

ERIC Educational Resources Information Center

Attempting to invert the pyramid to improve student achievement and increase all students' chances for success is not a new endeavor. For decades, educators have strategized, formed think tanks, and developed school improvement teams to find better ways to improve the achievement of all students. Currently, the No Child Left Behind Act (NCLB) is…

White-Hood, Marian; Shindel, Melissa

2006-01-01

234

Inverted Echo Sounder Development  

Microsoft Academic Search

The Inverted Echo Sounder (IES) is now being widely used to study the temporal variability in large-scale features of the temperature field of the oceans. The latest generation of instruments is microprocessor controlled for functional flexibility. Optional additional measurements of bottom pressure, temperature and ambient noise are now available. The latest system incorporates new echo detection electronics and a simplified

G. Chaplin; D. Watts

1984-01-01

235

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

PubMed Central

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

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

2013-01-01

236

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

PubMed

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

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

2013-01-01

237

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

NASA Astrophysics Data System (ADS)

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

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

2013-07-01

238

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

239

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

240

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

Microsoft Academic Search

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

Allan B. Plunkett; Fred G. Turnbull

1984-01-01

241

Fabrication of multi-level carbon nanotube arrays with adjustable patterns  

NASA Astrophysics Data System (ADS)

Multi-level carbon nanotube (CNT) arrays with adjustable patterns were prepared by a combination of the breath figure (BF) process and chemical vapor deposition. Polystyrene-b-poly(acrylic acid)/ferrocene was dissolved in carbon disulfide and cast onto a Si substrate covered with a transmission electron microscope grid in saturated relative humidity. A two-level microporous hybrid film with a block copolymer skeleton formed on the substrate after evaporation of the organic solvent and water. One level of ordered surface features originates from the contour of the hard templates; while the other level originates from the condensation of water droplets (BF arrays). Ultraviolet irradiation effectively cross-linked the polymer matrix and endowed the hybrid film with improved thermal stability. In the subsequent pyrolysis, the incorporated ferrocene in the hybrid film was oxidized and turned the polymer skeleton into the ferrous inorganic micropatterns. Either the cross-linked hybrid film or the ferrous inorganic micropatterns could act as a template to grow the multi-level CNT patterns, e.g. isolated and honeycomb-structured CNT bundle arrays perpendicular to the substrate.Multi-level carbon nanotube (CNT) arrays with adjustable patterns were prepared by a combination of the breath figure (BF) process and chemical vapor deposition. Polystyrene-b-poly(acrylic acid)/ferrocene was dissolved in carbon disulfide and cast onto a Si substrate covered with a transmission electron microscope grid in saturated relative humidity. A two-level microporous hybrid film with a block copolymer skeleton formed on the substrate after evaporation of the organic solvent and water. One level of ordered surface features originates from the contour of the hard templates; while the other level originates from the condensation of water droplets (BF arrays). Ultraviolet irradiation effectively cross-linked the polymer matrix and endowed the hybrid film with improved thermal stability. In the subsequent pyrolysis, the incorporated ferrocene in the hybrid film was oxidized and turned the polymer skeleton into the ferrous inorganic micropatterns. Either the cross-linked hybrid film or the ferrous inorganic micropatterns could act as a template to grow the multi-level CNT patterns, e.g. isolated and honeycomb-structured CNT bundle arrays perpendicular to the substrate. Electronic supplementary information (ESI) available. See DOI: 10.1039/c1nr11191d

Gong, Jianliang; Sun, Lichao; Zhong, Yawen; Ma, Chunyin; Li, Lei; Xie, Suyuan; Svrcek, Vladimir

2011-12-01

242

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

PubMed

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

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

2006-02-01

243

Multi-level Split Cord Malformation: Do We Need a New Classification?  

PubMed Central

Split cord malformations (SCMs) are thought to be rare abnormalities representing 3.8-5% of all spinal cord anomalies. The prevalence is estimated to be 1 in 5499 live births (0.02%), with a slight female predominance (1.3:1). Although the estimates of prevalence vary, Type I SCM occurs more frequently than Type II SCM. In this paper, we are reporting the clinical presentation and imaging findings of multi-level SCM in a 27-year-old male. A literature review of the embryological background of SCM and pathological hypothesis for this entity is provided. A systematic review has been conducted to identify multi-level SCM cases reported in the literature, followed by proposing a new classification system to further our understanding and management of SCMs. PMID:25161801

Alzhrani, Gmaan A; Al-Jehani, Hosam M; Melançon, Denis

2014-01-01

244

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

Microsoft Academic Search

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

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

2002-01-01

245

Grid connected DG systems based on Z-source NPC inverters  

Microsoft Academic Search

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

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

2011-01-01

246

Inverter ratio failure detector  

NASA Technical Reports Server (NTRS)

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

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

1974-01-01

247

Fatigue properties of RPC under cyclic loads of single-stage and multi-level amplitude  

Microsoft Academic Search

Fatigue properties of Reactive Powder Concrete (RPC) under axial compression of single-stage and multi-level amplitude in\\u000a cycles were studied. The tests reveal the fatigue life, the strain and residual life of the RPC samples. Through the analysis\\u000a of the test results under cyclic loads of single amplitude, the S-N curve of RPC and the evolution rule of macro-damage of\\u000a RPC

Mingzhe An; Ziruo Yu; Meili Sun; Shuaiquan Zheng; Lei Liang

2010-01-01

248

An adaptive, multi-level method for elliptic boundary value problems  

NASA Technical Reports Server (NTRS)

Subroutine PLTMG is a FORTRAN program for solving self-adjoint elliptic boundary value problems in general regions of R-squared. It is based on a piecewise linear triangle finite element method, an adaptive grid refinement procedure, and a multi-level iterative method to solve the resulting sets of linear equations. This paper describes the method and presents some numerical results and comparisons.

Bank, R. E.; Sherman, A. H.

1981-01-01

249

An 8 Gb multi-level NAND flash memory with 63 nm STI CMOS process technology  

Microsoft Academic Search

An 8 Gb multi-level NAND flash memory is fabricated in a 63 nm CMOS technology with shallow trench isolation. The cell and chip sizes are 0.02 ?m2 and 133 mm2, respectively. Performance improves to 4.4 MB\\/s by using the 2× program mode and by decreasing the cycle time from 50 ns to 30 ns. This also improves the read throughput

Dae-Seok Byeon; Sung-Soo Lee; Young-Ho Lim; Jin-Sung Park; Wook-Kee Han; Pan-Suk Kwak; Dong-Hwan Kim; Dong-Hyuk Chae; Seung-Hyun Moon; Seung-Jae Lee; Hyun-Chul Cho; Jung-Woo Lee; Moo-Sung Kim; Joon-Sung Yang; Young-Woo Park; Duk-Won Bae; Jung-Dal Choi; Sung-Hoi Hur; Kang-Deog Suh

2005-01-01

250

8 Gb MLC (multi-level cell) NAND flash memory using 63 nm process technology  

Microsoft Academic Search

For the first time, 8 Gb multi-level cell (MLC) NAND flash memory with 63 nm design rule is developed for mass storage applications. Its unit cell size is 0.0164 ?m2, the smallest ever reported. ArF lithography with off-axis illumination (OAI) was employed for critical layers. In addition, self-aligned floating poly-silicon gate (SAP), tungsten gate with an optimized re-oxidation process, oxide

Jong-Ho Park; Sung-Hoi Hur; Joon-Hee Leex; Jin-Taek Park; Jong-Sun Sel; Jong-Won Kim; Sang-Bin Song; Jung-Young Lee; Ji-Hwon Lee; Suk-Joon Son; Yong-Seok Kim; Min-Cheol Park; Soo-Jin Chai; Jung-Dal Choi; U-In Chung; Joo-Tae Moon; Kyeong-Tae Kim; Kinam Kim; Byung-Il Ryu

2004-01-01

251

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

252

Cross-Ontology Multi-level Association Rule Mining in the Gene Ontology  

PubMed Central

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

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

2012-01-01

253

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

254

Multi-level model of missed nursing care in the context of hospital merger.  

PubMed

The aim of this study was to delineate the multi-level relationships of individual registered nurse (RN) and nursing unit factors on missed nursing care. This was a quantitative model-building study using a descriptive, cross-sectional design. Surveys (N = 553) and administrative unit records from nurses in one hospital system undergoing merger were included. The results showed that 36% of the variation in missed nursing care is due to the unit context, with a corresponding 64% due to individual nurse differences. At the unit level, workload, skill mix, and critical unit type affected the amount of missed nursing care. At the individual nurse level, more experience, supplies problems, communication problems, and involvement in errors of commission all increased the perception of the amount of missed nursing care. Education level was not related to the amount of missed nursing care. The findings highlight the importance of unit- and individual-level interventions to redesign hospital nursing care. PMID:24869493

Castner, Jessica; Wu, Yow-Wu B; Dean-Baar, Susan

2015-04-01

255

Advanced inverter technology  

NASA Astrophysics Data System (ADS)

APL has three existing series resonant inverter-based power converters: Power--10kW, 5kW, 200kW, Topology--dc/dc 1/2 Bridge, ac/dc Full Bridge, dc/dc Dual Full Bridge, the control and protection circuits are different for the three units. The purpose of this program was to produce a control and protection architecture and functional circuits that would work with all three power stage topologies. The requirements for the three existing power stages were determined. The three existing control and protection circuits were analyzed. An IC technology study was performed to determine the optimum technology and fabrication method for SRI control and protection circuits. A control and protection architecture utilizing common functional circuits that would work with the three existing topologies was developed and block diagrams drawn. The functional tasks were portitioned into five custom parts. The requirements for the custom parts were described. A study was performed to assess the potential present and future functions for a microprocessor in a series resonant inverter. Packaging and thermal study was performed to investigate the problems associated with space deployment of a 200-kW series resonant inverter. Recommendations for control and protection architecture, functional circuits, parts selection, and fabrication as hybrid circuits are made.

Moser, R. L.

1984-07-01

256

Serving the army as secretaries: intersectionality, multi-level contract and subjective experience of citizenship.  

PubMed

With the growing elusiveness of the state apparatus in late modernity, military service is one of the last institutions to be clearly identified with the state, its ideologies and its policies. Therefore, negotiations between the military and its recruits produce acting subjects of citizenship with long-lasting consequences. Arguing that these negotiations are regulated by multi-level (civic, group, and individual) contracts, we explore the various meanings that these contracts obtain at the intersectionality of gender, class, and ethnicity; and examine how they shape the subjective experience of soldierhood and citizenship. More particularly, we analyse the meaning of military service in the retrospective life stories of Israeli Jewish women from various ethno-class backgrounds who served as army secretaries - a low-status, feminine gender-typed occupation within a hyper-masculine organization. Findings reveal that for women of the lower class, the organizing cultural schema of the multi-level contract is that of achieving respectability through military service, which means being included in the national collective. Conversely, for middle-class women, it is the sense of entitlement that shapes their contract with the military, which they expect to signify and maintain their privileged status. Thus, while for the lower class, the multi-level contract is about inclusion within the boundaries of the national collective, for the dominant groups, this contract is about reproducing social class hierarchies within national boundaries. PMID:25469654

Lomsky-Feder, Edna; Sasson-Levy, Orna

2015-03-01

257

Multi-level determinants of parasitic fly infection in forest passerines.  

PubMed

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

258

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

259

A Multi-Level Approach to Outreach for Geologic Sequestration Projects  

USGS Publications Warehouse

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

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

2009-01-01

260

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

NASA Astrophysics Data System (ADS)

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

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

2012-06-01

261

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

262

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

263

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

264

In good company? A multi-study, multi-level investigation of the effects of coworker relationships on employee well-being  

Microsoft Academic Search

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 government employees. Study 2 replicated and extended Study 1 by examining

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

2010-01-01

265

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

NASA Astrophysics Data System (ADS)

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.

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

2015-02-01

266

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

267

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

268

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

269

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

NASA Astrophysics Data System (ADS)

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

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

2001-06-01

270

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

271

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

PubMed

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

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

2013-08-21

272

Push pull microfluidics on a multi-level 3D CD  

PubMed Central

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

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

2013-01-01

273

A 3.3 V 128 Mb multi-level NAND flash memory for mass storage applications  

Microsoft Academic Search

The NAND flash memory was originally designed to target solid-state mass storage applications. Key requirements of mass storage, low cost and high serial access throughput, have been achieved by sacrificing a non-critical feature, fast random access. For a quantum step in cost reduction, the multi-level cell is combined with NAND flash memory. This 128 Mb multi-level NAND flash memory stores

Tae-Sung Jung; Young-Joon Choi; Kang-Deog Suh; Byung-Hoon Suh; Jin-Ki Kim; Young-Ho Lim; Yong-Nam Koh; Jong-Wook Park; Ki-Jong Lee; Jung-Hoon Park; Kee-Tae Park; Jang-Rae Kim; Jeong-Hyong Lee; Hyung-Kyu Lim

1996-01-01

274

Multi-objective optimization of tire carcass contours using a systematic aspiration-level adjustment procedure  

NASA Astrophysics Data System (ADS)

While forming a basic tire configuration and supporting most static and dynamic loads of automobiles, tire carcass influences major tire performances according to its contour. Among significant tire performances, we in this study intend to improve the automobile maneuverability and the tire durability by optimizing the sidewall carcass contour. In order to effectively maximize these multi-objectives, we refine the conventional satisficing trade-off methods (STOM) which were proposed originally for the multi-objective structural optimization, by introducing a systematic aspiration-level adjustment procedure. According to the systematic procedure, we perform the sidewall contour optimization that ideally distributes the sidewall carcass tension and minimizes strain-energy density at the belt edge. Since the tire analysis is highly nonlinear problem we employ an incremental analysis scheme, together with the finite-difference sensitivity scheme. Through the numerical experiment, we confirmed that the refined multi-objective optimization technique systematically leads to a final optimum sidewall contour, together with the stable and rapid convergence.

Cho, J. R.; Jeong, H. S.; Yoo, W. S.

275

Critical network effect induces business oscillations in multi-level marketing systems  

E-print Network

The "social-networking revolution" of late (e.g., with the advent of social media, Facebook, and the like) has been propelling the crusade to elucidate the embedded networks that underlie economic activity. An unexampled synthesis of network science and economics uncovers how the web of human interactions spurred by familiarity and similarity could potentially induce the ups and downs ever so common to our economy. Zeroing in on the million-strong global industry known as multi-level marketing, this study finds that such a socially-powered enterprise can only work stably through discrimination about who to make entrepreneurial connections with.

Juanico, Dranreb Earl

2012-01-01

276

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

277

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

E-print Network

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

Tolbert, Leon M.

278

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

279

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

SciTech Connect

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

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

2011-10-03

280

A New Carrier-Based PWM Providing Common-Mode-Current Reduction and DC-Bus Balancing for Three-Level Inverters  

Microsoft Academic Search

Adjustable-speed drives involve common-mode voltages, which generate common-mode currents flowing to the ground through stray capacitances of electric machines. These currents are known to provoke premature motor-bearing failures, as well as electromagnetic interferences disturbing neighbor electronic devices. Furthermore, high-voltage applications involve high levels of these conducted emissions, which must be lowered by using bulky and expensive filters. This paper aims

Arnaud Videt; Philippe Le Moigne; Nadir Idir; Philippe Baudesson; Xavier Cimetiere

2007-01-01

281

VLBI-resolution radio-map algorithms: Performance analysis of different levels of data-sharing on multi-socket, multi-core architectures  

NASA Astrophysics Data System (ADS)

A broad area in astronomy focuses on simulating extragalactic objects based on Very Long Baseline Interferometry (VLBI) radio-maps. Several algorithms in this scope simulate what would be the observed radio-maps if emitted from a predefined extragalactic object. This work analyzes the performance and scaling of this kind of algorithms on multi-socket, multi-core architectures. In particular, we evaluate a sharing approach, a privatizing approach and a hybrid approach on systems with complex memory hierarchy that includes shared Last Level Cache (LLC). In addition, we investigate which manual processes can be systematized and then automated in future works. The experiments show that the data-privatizing model scales efficiently on medium scale multi-socket, multi-core systems (up to 48 cores) while regardless of algorithmic and scheduling optimizations, the sharing approach is unable to reach acceptable scalability on more than one socket. However, the hybrid model with a specific level of data-sharing provides the best scalability over all used multi-socket, multi-core systems.

Tabik, S.; Romero, L. F.; Mimica, P.; Plata, O.; Zapata, E. L.

2012-09-01

282

Nanoreplicated positive and inverted submicrometer  

E-print Network

scattering (SERS) substrates with a pair of complementary structures--positive and inverted pyramid array while 1.6Ã?106 for inverted pyramid substrates with Rhodamine 6G as the target analyte. Based, the coinage metals including gold, silver, and copper are most commonly used as enhancing metal because

Cunningham, Brian

283

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

PubMed Central

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

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

2013-01-01

284

Microseismic mapping of hydraulic fractures using multi-level wireline receivers  

SciTech Connect

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

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

1995-07-01

285

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

286

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

287

Measurement of Low Level Explosives Reaction in Gauged Multi-dimensional Steven Impact Tests  

NASA Astrophysics Data System (ADS)

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

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

2002-07-01

288

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

289

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

SciTech Connect

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

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

2001-05-31

290

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

291

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

292

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

NASA Astrophysics Data System (ADS)

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.

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

2014-07-01

293

Geometric Phases, Noise and Non-adiabatic Effects in Multi-level Superconducting Systems  

NASA Astrophysics Data System (ADS)

Geometric phases depend neither on time nor on energy, but only on the trajectory of the quantum system in state space. In previous studies [1], we have observed them in a Cooper pair box qubit, a system with large anharmonicity. We now make use of a superconducting transmon-type qubit with low anharmonicity to study geometric phases in a multi-level system. We measure the contribution of the second excited state to the geometric phase and find very good agreement with theory treating higher levels perturbatively. Furthermore, we quantify non-adiabatic corrections by decreasing the manipulation time in order to optimize our geometric gate. Geometric phases have also been shown to be resilient against adiabatic field fluctuations [2]. Here, we analyze the effect of artificially added noise on the geometric phase for different system trajectories. [1] P. J. Leek et al., Science 318, 1889 (2007) [2] S. Filipp et al., Phys. Rev. Lett. 102, 030404 (2009)

Berger, S.; Pechal, M.; Abdumalikov, A. A.; Steffen, L.; Fedorov, A.; Wallraff, A.; Filipp, S.

2012-02-01

294

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

PubMed

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

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

2014-01-01

295

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

296

Multilevel conversion: high voltage choppers and voltage-source inverters  

Microsoft Academic Search

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

T. A. Meynard; H. Foch

1992-01-01

297

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

298

ARRA-Multi-Level Energy Storage and Controls for Large-Scale Wind Energy Integration  

SciTech Connect

The Project Objective is to design innovative energy storage architecture and associated controls for high wind penetration to increase reliability and market acceptance of wind power. The project goals are to facilitate wind energy integration at different levels by design and control of suitable energy storage systems. The three levels of wind power system are: Balancing Control Center level, Wind Power Plant level, and Wind Power Generator level. Our scopes are to smooth the wind power fluctuation and also ensure adequate battery life. In the new hybrid energy storage system (HESS) design for wind power generation application, the boundary levels of the state of charge of the battery and that of the supercapacitor are used in the control strategy. In the controller, some logic gates are also used to control the operating time durations of the battery. The sizing method is based on the average fluctuation of wind profiles of a specific wind station. The calculated battery size is dependent on the size of the supercapacitor, state of charge of the supercapacitor and battery wear. To accommodate the wind power fluctuation, a hybrid energy storage system (HESS) consisting of battery energy system (BESS) and super-capacitor is adopted in this project. A probability-based power capacity specification approach for the BESS and super-capacitors is proposed. Through this method the capacities of BESS and super-capacitor are properly designed to combine the characteristics of high energy density of BESS and the characteristics of high power density of super-capacitor. It turns out that the super-capacitor within HESS deals with the high power fluctuations, which contributes to the extension of BESS lifetime, and the super-capacitor can handle the peaks in wind power fluctuations without the severe penalty of round trip losses associated with a BESS. The proposed approach has been verified based on the real wind data from an existing wind power plant in Iowa. An intelligent controller that increases battery life within hybrid energy storage systems for wind application was developed. Comprehensive studies have been conducted and simulation results are analyzed. A permanent magnet synchronous generator, coupled with a variable speed wind turbine, is connected to a power grid (14-bus system). A rectifier, a DC-DC converter and an inverter are used to provide a complete model of the wind system. An Energy Storage System (ESS) is connected to a DC-link through a DC-DC converter. An intelligent controller is applied to the DC-DC converter to help the Voltage Source Inverter (VSI) to regulate output power and also to control the operation of the battery and supercapacitor. This ensures a longer life time for the batteries. The detailed model is simulated in PSCAD/EMTP. Additionally, economic analysis has been done for different methods that can reduce the wind power output fluctuation. These methods are, wind power curtailment, dumping loads, battery energy storage system and hybrid energy storage system. From the results, application of single advanced HESS can save more money for wind turbines owners. Generally the income would be the same for most of methods because the wind does not change and maximum power point tracking can be applied to most systems. On the other hand, the cost is the key point. For short term and small wind turbine, the BESS is the cheapest and applicable method while for large scale wind turbines and wind farms the application of advanced HESS would be the best method to reduce the power fluctuation. The key outcomes of this project include a new intelligent controller that can reduce energy exchanged between the battery and DC-link, reduce charging/discharging cycles, reduce depth of discharge and increase time interval between charge/discharge, and lower battery temperature. This improves the overall lifetime of battery energy storages. Additionally, a new design method based on probability help optimize the power capacity specification for BESS and super-capacitors. Recommendations include experimental imp

David Wenzhong Gao

2012-09-30

299

Towards Consistent Characterization of Quality and Uncertainty in Multi-sensor Aerosol Level 3 Satellite Data  

NASA Astrophysics Data System (ADS)

Climate models and various environmental monitoring and protection applications have been increasingly relying on satellite measurements. However, the user communities generally prefer not to deal with the complexities and peculiarities of Level 2 (swath) data from the different sensors. Instead, these users seek good quality gridded contiguous (no gaps) satellite data (Level 3), with uncertainties provided for each grid cell. There are various issues in quality and uncertainty associated with Level 3 satellite data, for which other communities (e.g., sea-surface temperature and precipitation) have developed specific solutions, based on their multi-satellite/sensor/year experience. The aerosol community will also benefit from addressing these issues and leveraging the lessons learned from other communities. Our objective is to develop a framework for aerosol data users to systematically characterize, capture, and provision quality and uncertainties in Level 3 satellite data. In particular, we note the semantic differences in quality/bias/uncertainty at the pixel, granule, product, and record levels. We outline various factors contributing to uncertainty or error budget: (1) physical factors (e.g., instrument, retrieval algorithm, aerosol spatial and temporal variability); (2) input errors associated with ancillary data used by the retrieval algorithm; (3) classification errors resulting from erroneous flagging of the data; (4) simulation errors resulting from the geophysical model used for the retrieval; and (5) sampling errors resulting from the averaging within the retrieval footprint. We describe the errors introduced by Level 2 to Level 3 and Level 3 to Level 4 processing steps, including gridding, aggregation, merging and analysis algorithm errors (e.g., representation, bias correction, and gap interpolation). We outline various methods for propagating (1) validation results from just a few points to global data uncertainty and (2) calibration and algorithm uncertainties to Level 3 gridded data. We attempt to capture requirements for quality vs. coverage for the needs of different communities. Finally, we address the question of how to label Level 3 data as validated. The larger community goal is to come up with recommendations for consistent generation of Levels 3 and 4 aerosol products, and consistent characterization of quality and uncertainty.

Leptoukh, G. G.

2010-12-01

300

Multi-level behaviours in agent-based simulation: colonic crypt cell populations  

NASA Astrophysics Data System (ADS)

Agent-based modelling and simulation is now beginning to establish itself as a suitable technique for studying biological systems. However, a major issue in using agent-based simulations to study complex systems such as those in Systems Biology is the fact that simulations are `opaque'. While we have knowledge of individuals' behaviour through agent rules and have techniques for evaluating global behaviour by aggregating the states of individuals, methods for identifying the interactive mechanisms giving rise to this global behaviour are lacking. Formulating precise hypotheses about these multi-level behaviours is also difficult without an established formalism for describing them. The complex event formalism allows relationships between agent-rule-generated events to be defined so that behaviours at different levels of abstraction to be described. Complex event types define categories of these behaviours, which can then be detected in simulation, giving us computational method for distinguishing between alternative interactive mechanisms underlying a higher level behaviour. We apply the complex event formalism to an agent-based model of cell populations in the colonic crypt and demonstrate how competition and selection events can be identified in simulation at both the individual and clonal level, allowing us to computationally test hypotheses about the interactive mechanisms underlying a clone's success.

Chen, Chih-Chun; Nagl, Sylvia B.; Clack, Christopher D.

301

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

302

Multi-component molecular-level body composition reference methods: evolving concepts and future directions.  

PubMed

Excess adiposity is the main phenotypic feature that defines human obesity and that plays a pathophysiological role in most chronic diseases. Measuring the amount of fat mass present is thus a central aspect of studying obesity at the individual and population levels. Nevertheless, a consensus is lacking among investigators on a single accepted 'reference' approach for quantifying fat mass in vivo. While the research community generally relies on the multi-component body volume class of 'reference' models for quantifying fat mass, no definable guide discerns among different applied equations for partitioning the four (fat, water, protein and mineral mass) or more quantified components, standardizes 'adjustment' or measurement system approaches for model-required labelled water dilution volumes and bone mineral mass estimates, or firmly establishes the body temperature at which model physical properties are assumed. The resulting differing reference strategies for quantifying body composition in vivo leads to small, but under some circumstances, important differences in the amount of measured body fat. Recent technological advances highlight opportunities to expand model applications to new subject groups and measured components such as total body protein. The current report reviews the historical evolution of multi-component body volume-based methods in the context of prevailing uncertainties and future potential. PMID:25645009

Heymsfield, S B; Ebbeling, C B; Zheng, J; Pietrobelli, A; Strauss, B J; Silva, A M; Ludwig, D S

2015-04-01

303

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

PubMed

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

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

2009-06-01

304

RH 1.5D: Polarized multi-level radiative transfer with partial frequency distribution  

NASA Astrophysics Data System (ADS)

RH 1.5D performs Zeeman multi-level non-local thermodynamical equilibrium calculations with partial frequency redistribution for an arbitrary amount of chemical species. Derived from the RH code and written in C, it calculates spectra from 3D, 2D or 1D atmospheric models on a column-by-column basis (or 1.5D). It includes optimization features to speed up or improve convergence, which are particularly useful in dynamic models of chromospheres. While one should be aware of its limitations, the calculation of spectra using the 1.5D or column-by-column is a good approximation in many cases, and generally allows for faster convergence and more flexible methods of improving convergence. RH 1.5D scales well to at least tens of thousands of CPU cores.

Pereira, Tiago M. D.; Uitenbroek, Han

2015-02-01

305

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

306

A multi-level pore-water sampler for permeable sediments  

USGS Publications Warehouse

The construction and operation of a multi-level piezometer (multisampler) designed to collect pore water from permeable sediments up to 230 cm below the sediment-water interface is described. Multisamplers are constructed from 1 1/2 inch schedule 80 PVC pipe. One-quarter-inch flexible PVC tubing leads from eight ports at variable depths to a 1 1/2 inch tee fitting at the top of the PVC pipe. Multisamplers are driven into the sediments using standard fence-post drivers. Water is pumped from the PVC tubing with a peristaltic pump. Field tests in Banana River Lagoon, Florida, demonstrate the utility of multisamplers. These tests include collection of multiple samples from the permeable sediments and reveal mixing between shallow pore water and overlying lagoon water.

Martin, J.B.; Hartl, K.M.; Corbett, D.R.; Swarzenski, P.W.; Cable, J.E.

2003-01-01

307

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

308

Multi-objective analysis of ground-level ozone concentration control.  

PubMed

To develop sound air quality plans, regional authorities should have instruments that link the complex behaviour of pollutants both in time and space with costs of emission reduction. The problem is particularly important for ground level ozone which forms kilometres away, hours later from the emission of its precursors. To approach this problem, a method (1) to identify local pollutant-precursor models on the basis of results from a large photochemical model (CALGRID), (2) to integrate them in a multi-objective mathematical program, together with an estimate of the emission reduction costs, is suggested. The method has been used to assess action priorities in Lombardy (Northern Italy). This area, characterised by a complex terrain, high urban and industrial emissions and a dense road network is often affected by severe photochemical pollution episodes during summer. PMID:15084357

Guariso, Giorgio; Pirovano, Guido; Volta, Marialuisa

2004-05-01

309

Performance evaluation of high voltage super junction MOSFETs for zero-voltage soft-switching inverter applications  

Microsoft Academic Search

This paper evaluates three different 600V-level super junction (SJ) MOSFETs employed in zero-voltage soft-switching inverter applications. Inverter efficiency was measured and compared with the same inverter test setup by only changing different MOSFETs. Besides high efficiency requirement, better switching performance is also highly appreciated in various inverter applications. Comparison test was done on each super junction MOSFET to investigate its

Sung-Yeul Park; Pengwei Sun; Wensong Yu; Jih-Sheng Lai

2010-01-01

310

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

311

Discovering context-specific relationships from biological literature by using multi-level context terms  

PubMed Central

Background The Swanson's ABC model is powerful to infer hidden relationships buried in biological literature. However, the model is inadequate to infer relations with context information. In addition, the model generates a very large amount of candidates from biological text, and it is a semi-automatic, labor-intensive technique requiring human expert's manual input. To tackle these problems, we incorporate context terms to infer relations between AB interactions and BC interactions. Methods We propose 3 steps to discover meaningful hidden relationships between drugs and diseases: 1) multi-level (gene, drug, disease, symptom) entity recognition, 2) interaction extraction (drug-gene, gene-disease) from literature, 3) context vector based similarity score calculation. Subsequently, we evaluate our hypothesis with the datasets of the "Alzheimer's disease" related 77,711 PubMed abstracts. As golden standards, PharmGKB and CTD databases are used. Evaluation is conducted in 2 ways: first, comparing precision of the proposed method and the previous method and second, analysing top 10 ranked results to examine whether highly ranked interactions are truly meaningful or not. Results The results indicate that context-based relation inference achieved better precision than the previous ABC model approach. The literature analysis also shows that interactions inferred by the context-based approach are more meaningful than interactions by the previous ABC model. Conclusions We propose a novel interaction inference technique that incorporates context term vectors into the ABC model to discover meaningful hidden relationships. By utilizing multi-level context terms, our model shows better performance than the previous ABC model. PMID:22595086

2012-01-01

312

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

313

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

NASA Astrophysics Data System (ADS)

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

Gentile, Martin J.; Barnes, William L.

2014-09-01

314

Segmentation of abdominal organs from CT using a multi-level, hierarchical neural network strategy.  

PubMed

Precise measurements on abdominal organs are vital prior to the important clinical procedures. Such measurements require accurate segmentation of these organs, which is a very challenging task due to countless anatomical variations and technical difficulties. Although, several features with various classifiers have been designed to overcome these challenges, abdominal organ segmentation via classification is still an emerging field in order to reach desired precision. Recent studies on multiple feature-classifier combinations show that hierarchical systems outperform composite feature-single classifier models. In this study, how hierarchical formations can translate to improved accuracy, when large size feature spaces are involved, is explored for the problem of abdominal organ segmentation. As a result, a semi-automatic, slice-by-slice segmentation method is developed using a novel multi-level and hierarchical neural network (MHNN). MHNN is designed to collect complementary information about organs at each level of the hierarchy via different feature-classifier combinations. Moreover, each level of MHNN receives residual data from the previous level. The residual data is constructed to preserve zero false positive error until the last level of the hierarchy, where only most challenging samples remain. The algorithm mimics analysis behaviour of a radiologist by using the slice-by-slice iteration, which is supported with adjacent slice similarity features. This enables adaptive determination of system parameters and turns into the advantage of online training, which is done in parallel to the segmentation process. Proposed design can perform robust and accurate segmentation of abdominal organs as validated by using diverse data sets with various challenges. PMID:24480371

Selver, M Alper

2014-03-01

315

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

316

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

317

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

318

A novel hysteresis current controller for multilevel single phase voltage source inverters  

Microsoft Academic Search

The application and benefits of hysteresis current control for two level voltage source inverters are well understood, but the extension of the strategy to multilevel inverters is much less established. Previous approaches have used either multiple hysteresis bands or a time based lockout strategy to decide when to switch to successive voltage levels, but these approaches are either complex, and\\/or

G. H. Bode; D. N. Zmood; P. C. Loh; D. G. Holmes

2001-01-01

319

A time-based double band hysteresis current regulation strategy for single-phase multilevel inverters  

Microsoft Academic Search

Most multilevel inverter hysteresis current regulators use either multiple hysteresis bands, or a time-based switching logic that forces the current error back to zero by recursively stepping through successive voltage levels. Of these two alternatives, the time-based approach has the merit of only requiring simple analog circuitry and digital logic to implement the voltage level selection process for inverters of

P. C. Loh; G. H. Bode; D. G. Holmes; T.A. Lipo

2002-01-01

320

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

NASA Astrophysics Data System (ADS)

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

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

2014-01-01

321

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

322

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

323

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

324

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

SciTech Connect

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

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

2014-05-01

325

RAETRAD model extensions for radon entry into multi-level buildings with basements or crawl spaces  

SciTech Connect

The RAETRAD model was generalized to characterize radon generation and movement from soils and building materials into multi-level buildings with basements or crawl spaces. With the generalization, the model retains its original simplicity and ease of use. The model calculates radon entry rates that are consistent with measurements published for basement test structures at Colorado State University, confirming approximately equal contributions from diffusion and pressure-driven air flow at indoor-outdoor air pressure differences of {Delta}P{sub i-o} = -3.5 Pa. About one-fourth of the diffusive radon entry comes from concrete slabs and three-fourths comes from the surrounding soils. Calculated radon entry rates with and without a barrier over floor-wall shrinkage cracks generally agree with Colorado State University measurements when a sustained pressure of {Delta}P{sub i-o} = -2 Pa is used to represent calm wind (<1 m, s{sup -1}) conditions. Calculated radon distributions in a 2-level house also are consistent with published measurements and equations.

Nielson, K.K.; Rogers, V.C.; Rogers, V.; Holt, R.B. [Rogers and Associates Engineering Corp., Salt Lake City, UT (United States)

1997-10-01

326

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

SciTech Connect

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

Baker, J.E.

1994-09-01

327

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

NASA Astrophysics Data System (ADS)

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

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

2012-02-01

328

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

PubMed

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

Jackson, Nicki; Denny, Simon; Ameratunga, Shanthi

2014-08-01

329

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

SciTech Connect

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

Baker, J.E.

1993-05-01

330

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

SciTech Connect

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

Baker, J.E.

1993-05-01

331

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

332

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

333

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

E-print Network

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

Kung, Andy

334

The tandem inverter: combining the advantages of voltage-source and current-source inverters  

Microsoft Academic Search

A combination of a current-source primary inverter and a voltage-source secondary inverter is proposed as the so-called tandem inverter. The primary inverter operates in the square-wave mode, handling most of the converted power, while its output harmonic currents are compensated by the much smaller secondary inverter. As a result, the tandem inverter, to be used for AC motor control, combines

A. M. Trznadlowski; F. Blaabjerg; J. K. Pedersen; N. Patriciu

1998-01-01

335

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

ERIC Educational Resources Information Center

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

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

2011-01-01

336

Studying Directory Access Patterns via Reuse Distance Analysis and Evaluating Their Impact on Multi-Level Directory Caches  

E-print Network

Studying Directory Access Patterns via Reuse Distance Analysis and Evaluating Their Impact on Multi-Level Directory Caches Minshu Zhao, and Donald Yeung Department of Electrical and Computer Engineering University core count. One of the key limiters to scaling will be the on-chip directory cache. Our work

Yeung, Donald

337

Multi-level transparent touchscreen for mobile applications Siarhei Vishniakou, Francis Tsui, Frank WangTeam 7  

E-print Network

Multi-level transparent touchscreen for mobile applications Siarhei Vishniakou, Francis Tsui, Frank and capacitive · Capacitive touchscreens require conducting object to operate · Resistive touchscreens degrade location and amount of applied pressure · Each pixel is a transparent zinc-oxide thin-film transistor (Zn

California at San Diego, University of

338

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

339

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

340

Plasma N terminal pro-brain natriuretic peptide levels and its determinants in a multi-ethnic population  

Microsoft Academic Search

This study documents the determinants and plasma levels of N-terminal pro-brain natriuretic peptide (NT-proBNP) among hypertensive and normotensive subjects in a multi-ethnic population in the United Arab Emirates (UAE). We obtained demographic, anthropometric and clinical data, together with fasting NT-proBNP and biochemical indices from 128 hypertensive patients and 138 normotensive subjects matched for age, gender and ethnicity. Plasma NT-proBNP levels

A M Abdulle; N J D Nagelkerke; A Adem; S Abouchacra; J Y Pathan; M Al-Rukhaimi; M N Suleiman; M C Mathew; M G Nicholls; E N Obineche

2007-01-01

341

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

PubMed Central

With the availability of newer and cheaper sequencing methods, genomic data are being generated at an increasingly fast pace. In spite of the high degree of complexity of currently available search routines, the massive number of sequences available virtually prohibits quick and correct identification of large groups of sequences sharing common traits. Hence, there is a need for clustering tools for automatic knowledge extraction enabling the curation of large-scale databases. Current sophisticated approaches on sequence clustering are based on pairwise similarity matrices. This is impractical for databases of hundreds of thousands of sequences as such a similarity matrix alone would exceed the available memory. In this paper, a new approach called MultiLevel Clustering (MLC) is proposed which avoids a majority of sequence comparisons, and therefore, significantly reduces the total runtime for clustering. An implementation of the algorithm allowed clustering of all 344,239 ITS (Internal Transcribed Spacer) fungal sequences from GenBank utilizing only a normal desktop computer within 22 CPU-hours whereas the greedy clustering method took up to 242 CPU-hours. PMID:25355642

Vu, Duong; Szöke, Szániszló; Wiwie, Christian; Baumbach, Jan; Cardinali, Gianluigi; Röttger, Richard; Robert, Vincent

2014-01-01

342

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

343

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

344

A multi-level spatial clustering algorithm for detection of disease outbreaks.  

PubMed

In this paper, we proposed a Multi-level Spatial Clustering (MSC) algorithm for rapid detection of emerging disease outbreaks prospectively. We used the semi-synthetic data for algorithm evaluation. We applied BARD algorithm [1] to generate outbreak counts for simulation of aerosol release of Anthrax. We compared MSC with two spatial clustering algorithms: Kulldorff's spatial scan statistic [2] and Bayesian spatial scan statistic [3]. The evaluation results showed that the areas under ROC had no significant difference among the three algorithms, so did the areas under AMOC. MSC demonstrated significant computational efficiency (100 + times faster) and higher PPV. However, MSC showed 2-6 hours delay on average for outbreak detection when the false alarm rate was lower than 1 false alarm per 4 weeks. We concluded that the MSC algorithm is computationally efficient and it is able to provide more precise and compact clusters in a timely manner while keeping high detection accuracy (cluster sensitivity) and low false alarm rates. PMID:18999304

Que, Jialan; Tsui, Fu-Chiang

2008-01-01

345

A Multi-level Spatial Clustering Algorithm for Detection of Disease Outbreaks  

PubMed Central

In this paper, we proposed a Multi-level Spatial Clustering (MSC) algorithm for rapid detection of emerging disease outbreaks prospectively. We used the semi-synthetic data for algorithm evaluation. We applied BARD algorithm[1] to generate outbreak counts for simulation of aerosol release of Anthrax. We compared MSC with two spatial clustering algorithms: Kulldorff’s spatial scan statistic[2] and Bayesian spatial scan statistic[3]. The evaluation results showed that the areas under ROC had no significant difference among the three algorithms, so did the areas under AMOC. MSC demonstrated significant computational effciency (100+ times faster) and higher PPV. However, MSC showed 2–6 hours delay on average for outbreak detection when the false alarm rate was lower than 1 false alarm per 4 weeks. We concluded that the MSC algorithm is computationally efficient and it is able to provide more precise and compact clusters in a timely manner while keeping high detection accuracy (cluster sensitivity) and low false alarm rates. PMID:18999304

Que, Jialan; Tsui, Fu-Chiang

2008-01-01

346

InSbTe Phase-Change Materials for High Performance Multi-Level Recording  

NASA Astrophysics Data System (ADS)

Eutectic-based InSbTe phase-change materials have been developed for low sigma-to-dynamic range (SDR) multi-level (ML) performance at linear track velocities (LTVs) of 1.9 m/s to 6 m/s. Compositions with the stoichiometry Inx(Sb72Te28)100-x (3.9

Daly-Flynn, Kelly; Strand, David

2003-02-01

347

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.

348

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

349

Multi-antenna RF Ion Source at a High RF Power Level  

SciTech Connect

A multi-antenna radio-frequency ion source with a Faraday shield is newly tested at a high RF power level in a large area negative ion source of 1/5th scale of the Large Helical Device-NNBI ion source. Inductively coupled dense hydrogen plasmas were generated uniformly over an area of 25x25 cm{sup 2} at an RF input power up to 300 kW for a 10 ms pulse duration. A large negative plasma potential for the non-Faraday shielded antenna was remarkably reduced by introducing a Faraday shield. The positive ion saturation current density measured by Langmuir probe reached 148 mA/cm{sup 2} at 174 kW around the center of the plasma. The optimal hydrogen filling pressure ranged around 0.13 Pa- 0.4 Pa for the positive ions. Ion beam extraction with a single hole ({phi} 0.5 cm) extractor has been studied systematically. A maximum H{sup -} ion beam current density of 1.6 mA/cm{sup 2} was obtained preliminarily. It was confirmed that the plasma profile was controllable by both the number and configuration of the antennas.

Oka, Y.; Kaneko, O.; Takeiri, Y.; Tsumori, K.; Osakabe, M.; Ikeda, K.; Nagaoka, K.; Asano, E.; Sato, M.; Kondo, T.; Shibuya, M.; Komada, S. [National Institute for Fusion Science/-NINS-, Oroshi, Toki 509-5292, Gifu (Japan); Shoji, T. [Nagoya university, Chikusa, Nagoya 464-8603 (Japan)

2009-03-12

350

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

351

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

NASA Astrophysics Data System (ADS)

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

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

2011-08-01

352

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

353

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

354

MultiLevel NAND Flash Memory with 63 nm-Node TANOS (Si-Oxide-SiN-Al2O3TaN) Cell Structure  

Microsoft Academic Search

For the first time, multi-level NAND flash memories with a 63 nm design rule are developed successfully using charge trapping memory cells of Si\\/SiO2\\/SiN\\/Al2O3\\/TaN (TANOS). We successfully integrated TANOS cells into multi-gigabit multi-level NAND flash memory without changing the memory window and circuit design of the conventional floating-gate type NAND flash memories by improving erase speed. The evolved TANOS cells

Chang-Hyun Lee; Jungdal Choi; Changseok Kang; Yoocheol Shin; Jang-Sik Lee; Jongsun Sel; Jaesung Sim; Sanghun Jeon; Byeong-In Choe; Dukwon Bae; Kinam Kim

2006-01-01

355

Evaluation of a high power ARCP voltage source inverter with IGCTs  

Microsoft Academic Search

An evaluation and comparison of a two-level conventional voltage source inverter (VSI) and an auxiliary resonant commutated pole voltage source inverter (ARCPVSI) featuring IGCTs for a 3 MVA application is presented. Design issues of both topologies are addressed. The IGCT loss approximations are based on extensive measurements of the devices under hard and soft switching conditions. The results show that

S. Bernet; R. Teichmann; J. Weber; P. K. Steimer

1999-01-01

356

Abstract--A reconfiguration technique for multilevel inverters incorporating a diagnostic system based on neural  

E-print Network

it uses several level dc voltage sources which would be available from batteries or fuel cells [1 will disconnect the power sources from the multilevel inverter system whenever a fault occurs, stopping source inverter (VSI) system. The various fault modes for an induction motor are investigated in [3

Tolbert, Leon M.

357

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

358

A multi-level strategy for anticipating future glacier lake formation and associated hazard potentials  

NASA Astrophysics Data System (ADS)

Due to the expected atmospheric warming, mountain glaciers will retreat, potentially collapse or even vanish completely during the 21st century. When overdeepened parts of the glacier bed are exposed in the course of glacier retreat, glacier lakes can form. Such lakes have a potential for hydropower production, which is an important source of renewable energy. Furthermore they are important elements in the perception of high-mountain landscapes and they can compensate the loss of landscape attractiveness from glacier shrinkage to a certain degree. However, glacier lakes are also a potential source of serious flood and debris flow hazards, especially in densely populated mountain ranges. Thus, methods for early detection of sites with potential lake formation are important for early planning and development of protection concepts. In this contribution we present a multi-scale approach to detect sites with potential future lake formation on four different levels of detail. The methods are developed, tested and - as far as possible - verified in the Swiss Alps; but they can be applied to mountain regions all over the world. On a first level, potential overdeepenings are estimated by selecting flat parts (slope < 5°) of the current glacier surface based on a digital elevation model (DEM) and digital glacier outlines. The same input data are used on the second level for a manual detection of overdeepenings, which are expected at locations where the following three criteria apply: (a) A distinct increase of the glacier surface slope in down-glacier direction; (b) an enlarged width followed by a narrow glacier part; and (c) regions with compressive flow (no crevasses) followed by extending flow (heavily crevassed). On the third level, more sophisticated approaches to model the glacier bed topography are applied to get more quantitative information on potential future lakes. Based on the results of this level, scenarios of future lake outbursts can be modeled with simple flow routing models. Finally, for potentially critical or dangerous situations, on-site geophysical measurements such as ground penetrating radar applied on different sections of a glacier can be performed on the fourth level to investigate the overdeepenings in more detail. These methods are verified based on historical data from the Trift glacier in the Bernese Alps, where a lake formed in front of the glacier since the 1990s up to the present. Potential future lake scenarios are presented for two regions in the Swiss Alps and the outburst potential of such future lakes is investigated for the Bernina region. The proposed method is an important step towards early detection of new potential flood hazards related to rapid glacier retreat. At the same time, it can form a basis for an integrative risk and benefit management relating to new glacier lakes.

Frey, Holger; Haeberli, Wilfried; Huggel, Christian; Linsbauer, Andreas

2010-05-01

359

1412 IEEE TRANSACTIONS ON VERY LARGE SCALE INTEGRATION (VLSI) SYSTEMS, VOL. 18, NO. 10, OCTOBER 2010 Improving Multi-Level NAND Flash Memory  

E-print Network

2010 Improving Multi-Level NAND Flash Memory Storage Reliability Using Concatenated BCH-TCM Coding Shu, multi-level per cell (MLC) NAND flash memories are dominating global flash memory market due to their appealing storage den- sity advantage. However, continuous technology scaling makes MLC NAND flash memories

Zhang, Tong

360

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

361

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

NASA Astrophysics Data System (ADS)

Dairy farming in California's Central Valley is a significant source of nitrate to underlying aquifers. One approach to mitigation is to implement farm-scale management plans that reduce nutrient loading to groundwater while sustaining crop yield. While the effect of different management practices on crop yield is easily measured, their effect on groundwater quality has only infrequently been evaluated. Documenting and predicting the impact of management on water quality requires a quantitative assessment of transport (including timescale and mixing) through the vadose and saturated zones. In this study, we measured tritium, helium isotopic composition, and noble gas concentrations in groundwater drawn from monitor wells on several dairies in the Lower San Joaquin Valley and Tulare Lake Basin of California's Central Valley in order to predict the timescales on which changes in management may produce observable changes in groundwater quality. These dairies differ in age (from <10 to >100 years old), thickness of the vadose zone (from <10 to 60 m), hydrogeologic setting, and primary source of irrigation water (surface or groundwater). All of the dairies use manure wastewater for irrigation and fertilization. Three of the dairies have implemented management changes designed to reduce nutrient loading and/or water usage. Monitor wells in the southern Tulare Lake Basin dairies were installed by UC-Davis as multi-level nested wells allowing depth profiling of tritium and noble gases at these sites. Tritium/helium-3 groundwater ages, calculated using a simple piston-flow model, range from <2 to >50 years. Initial tritium (the sum of measured tritium and tritiogenic helium-3) is close to or slightly above precipitation in the calculated recharge year for young samples; and significantly above the precipitation curve for older samples. This pattern is consistent with the use of 20-30 year old groundwater recharged before 1980 for irrigation, and illustrates how irrigation with groundwater can complicate the use of tritium alone for age dating. The presence of radiogenic helium-4 in several samples with measurable tritium provides evidence of mixing between pre-modern and younger groundwater. Groundwater age-depth relationships are complicated, consistent with transient flow patterns in shallow agricultural groundwaters affected by irrigation pumping and recharge. For the multi-level installations in the southern dairies, both depth profiles and re-sampling after significant changes in groundwater elevation emphasize the need to sample groundwater within 3 meters of the water table to obtain "first-encounter" groundwater with a tritium/helium-3 age of less than 5 years, and to use age tracers to identify wells and groundwater conditions suitable for monitoring and assessment of best management practice impacts on underlying groundwater quality. This work was carried out with funding from Sustainable Conservation and the California State Water Resources Control Board in collaboration with UC-Davis, and was performed under the auspices of the U.S. DOE by LLNL under Contract DE-AC52-07NA27344.

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

2011-12-01

362

Inverted spectra of SWCNT films  

Microsoft Academic Search

Diffuse Reflectance for purified single wall carbon nanotube (SWCNT) films and its relation to absorptance in the wavelength range 0.6 mum to 2 mum are inverted when compared to absorptivity data in the literature. This surprising behavior has been corroborated by diffuse reflectance measurements and shows that the reflectance is a substantial part of the unique optical behavior. Typically, the

John Lehman; Katherine Hurst; Lara Roberson; Kathryn Nield; John Hamlin

2008-01-01

363

Stroboscopic study of the inverted pendulum  

NASA Astrophysics Data System (ADS)

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, London, 1965)] theories are used as analogs to study the behavior of the inverted and the partially inverted pendulum.

Michaelis, M. M.

1985-11-01

364

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

365

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

366

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

367

AN "AC INDUCTOR" BASED GRID CONNECTED INVERTER  

E-print Network

sourcing inverters where the small disturbance at the line voltage may lead to current run away inverters, most of them share a common feature - their outputs are basically voltage sources. Consequently, is to apply an inverter with an Output Current Sourcing (OCS) behavior rather than the voltage sourcing one

368

Parallel operation of voltage source inverters  

Microsoft Academic Search

Parallel operating systems of voltage source inverters with other inverters or with the utility source are sensitive to disturbances from the load or other sources and can easily be damaged by overcurrent. Thus extremely careful attention should be given to the system design of parallel operating inverters. Types of system configuration, control methods, and means of protection against failure are

T. Kawabata; S. Higashino

1988-01-01

369

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

370

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

PubMed Central

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

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

2013-01-01

371

Multi-Ethnic Curriculum Units Primary, Intermediate, and Secondary Levels. A Model Program in Multi-Ethnic Heritage Studies.  

ERIC Educational Resources Information Center

This curriculum guide contains a preface and an introduction for each level of learning plus three parts. The preface and introduction make a case for reversing the trend in American schools of teaching children to be well-assimilated Americans. They state, rather, that children should be encouraged to know and be proud of their ethnic heritage as…

Mankato State Univ., Minn.

372

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

373

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

374

Taming HotSpots in DHT Inverted Indexes  

Microsoft Academic Search

DHT systems are structured overlay networks capable of using P2P resources as a scalable platform for very large data storage applications. However, their eciency expects a level of uni- formity in the association of data to index keys that is often not present in inverted indexes. Index data tends to follow non- uniform distributions, often power law distributions, creating in-

Nuno Lopes; Carlos Baquero

375

Suspended Patch Antenna Array With Electromagnetically Coupled Inverted Microstrip Feed  

NASA Technical Reports Server (NTRS)

The paper demonstrates a four-element suspended patch antenna array, with a parasitic patch layer and an electromagnetically coupled inverted microstrip feed, for linear polarization at K-Band frequencies. This antenna has the following advantages over conventional microstrip antennas: First, the inverted microstrip has lower attenuation than conventional microstrip; hence, conductor loss associated with the antenna corporate feed is lower resulting in higher gain and efficiency. Second, conventional proximity coupled patch antennas require a substrate for the feed and a superstrate for the patch. However, the inverted microstrip fed patch antenna makes use of a single substrate, and hence, is lightweight and low cost. Third, electromagnetic coupling results in wider bandwidth. Details regarding the design and fabrication will be presented as well as measured results including return loss, radiation patterns and cross-polarization levels.

Simons, Rainee N.

2000-01-01

376

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

377

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

378

Low-Power High-Throughput BCH Error Correction VLSI Design for MultiLevel Cell NAND Flash Memories  

Microsoft Academic Search

As the reliability is a critical issue for new generation multi-level cell (MLC) flash memories, there is growing call for fast and compact error correction code (ECC) circuit with minimum impact on memory access time and chip area. This paper presents a high-throughput and low-power ECC scheme for MLC NAND flash memories. The BCH encoder and decoder architecture features byte-wise

Wei Liu; Junrye Rho; Wonyong Sung

2006-01-01

379

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

380

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

381

The IHMC CmapTools software in research and education: a multi-level use case in Space Meteorology  

NASA Astrophysics Data System (ADS)

The IHMC (Institute for Human and Machine Cognition, Florida University System, USA) CmapTools software is a powerful multi-platform tool for knowledge modelling in graphical form based on concept maps. In this work we present its application for the high-level development of a set of multi-level concept maps in the framework of Space Meteorology to act as the kernel of a space meteorology domain ontology. This is an example of a research use case, as a domain ontology coded in machine-readable form via e.g. OWL (Web Ontology Language) is suitable to be an active layer of any knowledge management system embedded in a Virtual Observatory (VO). Apart from being manageable at machine level, concept maps developed via CmapTools are intrinsically human-readable and can embed hyperlinks and objects of many kinds. Therefore they are suitable to be published on the web: the coded knowledge can be exploited for educational purposes by the students and the public, as the level of information can be naturally organized among linked concept maps in progressively increasing complexity levels. Hence CmapTools and its advanced version COE (Concept-map Ontology Editor) represent effective and user-friendly software tools for high-level knowledge represention in research and education.

Messerotti, Mauro

2010-05-01

382

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

383

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

384

OptCom: a multi-level optimization framework for the metabolic modeling and analysis of microbial communities.  

PubMed

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

2012-02-01

385

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

NASA Astrophysics Data System (ADS)

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

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

2014-08-01

386

Development and applications of a multi-level strain energy method for detecting finite element modeling errors  

NASA Technical Reports Server (NTRS)

A computational procedure is described which can be used efficiently in identifying modeling errors which may arise from development of a structural finite element model. The procedure, which is referred to as the multi-level strain energy check, is set up in the form of a set of NASTRAN DMAP alters which provide sufficient information about the modeling errors at G-Set, N-Set, and F-Set levels. This technique was applied to two NASTRAN models, namely, the AH-64A and AH-1G models. Two modeling errors were identified for the AH-1G, which were then corrected.

Hashemi-Kia, Mostafa; Kilroy, Kevin L.; Parker, G.

1990-01-01

387

Fabrication of organic complementary inverter  

NASA Astrophysics Data System (ADS)

We have fabricated organic complementary inverter comprised of p-channel copper phthalocyanine(CuPc) and n-channel hexadecafluoro phthalocyanine (F16CuPc) based organic thin film transistors (OTFTs) with single Cu metal electrode for both type of OTFTs. The work function of Cu is nearly equal to the highest occupied molecular orbital (HOMO) of CuPc and lowest unoccupied molecular orbital (LUMO) of F16CuPc hence it can be used as source/drain electrode for both type of OTFTs which shows field effect mobilities of CuPc and F16CuPc based OTFTs are 1.27x10-3cm2V-1S-1 and 3.30x10-4cm2V- 1S-1 respectively. Voltage transfer characteristics of complementary inverter show high noise margins and switching voltage around VDD/2 with a maximum gain in the order of 20.

Yadav, Sarita; Ghosh, Subhasis

2012-10-01

388

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

389

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

390

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

391

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

392

Bayesian mixed hidden Markov models: a multi-level approach to modeling categorical outcomes with differential misclassification.  

PubMed

Questionnaire-based health status outcomes are often prone to misclassification. When studying the effect of risk factors on such outcomes, ignoring any potential misclassification may lead to biased effect estimates. Analytical challenges posed by these misclassified outcomes are further complicated when simultaneously exploring factors for both the misclassification and health processes in a multi-level setting. To address these challenges, we propose a fully Bayesian mixed hidden Markov model (BMHMM) for handling differential misclassification in categorical outcomes in a multi-level setting. The BMHMM generalizes the traditional hidden Markov model (HMM) by introducing random effects into three sets of HMM parameters for joint estimation of the prevalence, transition, and misclassification probabilities. This formulation not only allows joint estimation of all three sets of parameters but also accounts for cluster-level heterogeneity based on a multi-level model structure. Using this novel approach, both the true health status prevalence and the transition probabilities between the health states during follow-up are modeled as functions of covariates. The observed, possibly misclassified, health states are related to the true, but unobserved, health states and covariates. Results from simulation studies are presented to validate the estimation procedure, to show the computational efficiency due to the Bayesian approach and also to illustrate the gains from the proposed method compared to existing methods that ignore outcome misclassification and cluster-level heterogeneity. We apply the proposed method to examine the risk factors for both asthma transition and misclassification in the Southern California Children's Health Study. PMID:24254432

Zhang, Yue; Berhane, Kiros

2014-04-15

393

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

394

Integration of multi-level biomarker responses to cadmium and benzo[k]fluoranthene in the pale chub (Zacco platypus).  

PubMed

The Cd exposure for 14 days significantly increased both the molecular (DNA single-strand breaks) and biochemical (metallothionein concentrations) biomarkers in the freshwater pale chub, Zacco platypus, whereas changes in the histological and physiological biomarker responses were negligible. The BkF exposure for 14 days led to significant increases in the mRNA expression of catalase and superoxide dismutase, 7-ethoxyresorufin-O-deethylase enzymatic activity and DNA single-strand breakage at the molecular and biochemical levels. In addition, exposure to 50?g/L of BkF induced histological alteration in the liver, with significant changes to the liver somatic index and condition factor at the physiological level. The integration of multi-level biomarker responses at the molecular, biochemical and physiological levels was highly correlated with the concentrations of Cd and BkF. PMID:25217733

Kim, Woo-Keun; Lee, Sung-Kyu; Park, June-Woo; Choi, Kyungho; Cargo, Jordan; Schlenk, Daniel; Jung, Jinho

2014-12-01

395

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

USGS Publications Warehouse

Partitioning the variance of a response by design levels is challenging for binomial and other discrete outcomes. Goldstein (2003) proposed four definitions for variance partitioning coefficients (VPC) under a two-level logistic regression model. In this study, we explicitly derived formulae for multi-level logistic regression model and subsequently studied the distributional properties of the calculated VPCs. Using simulations and a vegetation dataset, we demonstrated associations between different VPC definitions, the importance of methods for estimating VPCs (by comparing VPC obtained using Laplace and penalized quasilikehood methods), and bivariate dependence between VPCs calculated at different levels. Such an empirical study lends an immediate support to wider applications of VPC in scientific data analysis.

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

2008-01-01

396

A public health framework to translate risk factors related to political violence and war into multi-level preventive interventions.  

PubMed

Political violence, armed conflicts and human rights violations are produced by a variety of political, economic and socio-cultural factors. Conflicts can be analyzed with an interdisciplinary approach to obtain a global understanding of the relative contribution of risk and protective factors. A public health framework was designed to address these risk factors and protective factors. The framework resulted in a matrix that combined primary, secondary and tertiary interventions with their implementation on the levels of the society-at-large, the community, and the family and individual. Subsequently, the risk and protective factors were translated into multi-sectoral, multi-modal and multi-level preventive interventions involving the economy, governance, diplomacy, the military, human rights, agriculture, health, and education. Then the interventions were slotted in their appropriate place in the matrix. The interventions can be applied in an integrative form by international agencies, governments and non-governmental organizations, and molded to meet the requirements of the historic, political-economic and socio-cultural context. The framework maps the complementary fit among the different actors while engaging themselves in preventive, rehabilitative and reconstructive interventions. The framework shows how the economic, diplomatic, political, criminal justice, human rights, military, health and rural development sectors can collaborate to promote peace or prevent the aggravation or continuation of violence. A deeper understanding of the association between risk and protective factors and the developmental pathways of generic, country-specific and culture-specific factors leading to political violence is needed. PMID:19883967

De Jong, Joop T V M

2010-01-01

397

A time-based double-band hysteresis current regulation strategy for single-phase multilevel inverters  

Microsoft Academic Search

Most multilevel inverter hysteresis current regulators use either multiple hysteresis bands, or a time-based switching logic that forces the current error back to zero by recursively stepping through successive voltage levels. Of these two alternatives, the time-based approach has the merit of only requiring simple analog circuitry and digital logic to implement the voltage level selection process for inverters of

Poh Chiang Loh; Gerwich H. Bode; Donald Grahame Holmes; Thomas A. Lipo

2003-01-01

398

Weight gain prevention in the school worksite setting: Results of a multi-level cluster randomized trial  

PubMed Central

Objective To describe the effectiveness, reach and implementation of a weight gain prevention intervention among public school employees. Method A multi-level intervention was tested in a cluster randomized trial among 782 employees in 12 central Massachusetts public high schools from 2009 to 2012. The intervention targeted the nutrition and physical activity environment and policies, the social environment and individual knowledge, attitudes and skills. The intervention was compared to a materials only condition. The primary outcome measures were change in weight and body mass index (BMI) at 24-month follow-up. Implementation of physical environment, policy and social environment strategies at the school and interpersonal levels, and intervention participation at the individual level were assessed. Results At 24-month follow-up, there was a net change (difference of the difference) of ?3.03 pounds (p=.04) and of ?.48 BMI units (p=.05) between intervention and comparison conditions. The majority of intervention strategies were successfully implemented by all intervention schools, although establishing formal policies was challenging. Employee participation in programs targeting the physical and social environment was maintained over time. Conclusion This study supports that a multi-level intervention integrated within the organizational culture can be successfully implemented and prevent weight gain in public high school employees. PMID:24345602

Lemon, Stephenie C.; Wang, Monica L.; Wedick, Nicole M.; Estabrook, Barbara; Druker, Susan; Schneider, Kristin L.; Li, Wenjun; Pbert, Lori

2014-01-01

399

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

400

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

401

Multi-objective meta level soft computing-based evolutionary structural design  

Microsoft Academic Search

Evolutionary structural design has been the topic of much recent research; however, such designs are usually hampered by the time-consuming stage of prototype evaluations using standard finite element analysis (FEA). Replacing the time-consuming FEA by neural network approximations may be a computationally efficient alternative, but the error in such approximation may misguide the optimization procedure. In this paper, a multi-objective

Amir-R. Khorsand; Mohammad-R. Akbarzadeh-T

2007-01-01

402

Multi-scale environmental accounting: methodological lessons from the application of NAMEA at sub-national levels.  

PubMed

Extending the application of integrated environmental and economic accounts from the national to the local level of government serves several purposes. They can be used not only as an instrument for communicating on the state of the environment and reporting the results of policies, but also as an operational tool - for setting the objectives and designing policies - if made available to the local authorities who have responsibility over the administration of natural resources, land use and conservation policies. The aim of the paper is to test the feasibility of applying hybrid flow accounts at the intermediate and local government levels. As an illustration, NAMEA for air emissions and wastes is applied to a Region, a Province and a Municipality, thus covering the three nested levels of local government in Italy. The study identifies the main issues raised by multi-scale environmental accounting and provides an applied discussion of feasible solutions. PMID:24141065

Dalmazzone, Silvana; La Notte, Alessandra

2013-11-30

403

Evaluation of multi-level social learning for sustainable landscapes: perspective of a development initiative in Bergslagen, Sweden.  

PubMed

To implement policies about sustainable landscapes and rural development necessitates social learning about states and trends of sustainability indicators, norms that define sustainability, and adaptive multi-level governance. We evaluate the extent to which social learning at multiple governance levels for sustainable landscapes occur in 18 local development initiatives in the network of Sustainable Bergslagen in Sweden. We mapped activities over time, and interviewed key actors in the network about social learning. While activities resulted in exchange of experiences and some local solutions, a major challenge was to secure systematic social learning and make new knowledge explicit at multiple levels. None of the development initiatives used a systematic approach to secure social learning, and sustainability assessments were not made systematically. We discuss how social learning can be improved, and how a learning network of development initiatives could be realized. PMID:23475659

Axelsson, Robert; Angelstam, Per; Myhrman, Lennart; Sädbom, Stefan; Ivarsson, Milis; Elbakidze, Marine; Andersson, Kenneth; Cupa, Petr; Diry, Christian; Doyon, Frederic; Drotz, Marcus K; Hjorth, Arne; Hermansson, Jan Olof; Kullberg, Thomas; Lickers, F Henry; McTaggart, Johanna; Olsson, Anders; Pautov, Yurij; Svensson, Lennart; Törnblom, Johan

2013-03-01

404

Research on self-inverting exhaust muffler  

Microsoft Academic Search

Self-inverting exhaust muffler is an active control muffler based on acoustic interference principle. Compared with the passive exhaust muffler, the exhaust resistance of self-inverting exhaust muffler is smaller. Therefore, the engine power loss is smaller. Compared with the active exhaust muffler, the electric power loss of self-inverting exhaust muffler is smaller and structure is simpler, so that it can be

Zhang Daizhi; Chen Daimin; Yang Yanjun; Sun Binghan

2010-01-01

405

Inverted Troughs and Their Associated Precipitation Regimes  

NSDL National Science Digital Library

This Webcast features Phil Schumacher, NWS Sioux Falls, South Dakota discussing the conditions that dictate the location of precipitation relative to inverted troughs. Phil presents a composite case study based on collaborative research with Dr. R. Weisman and others, as well as two examples of inverted trough events in the Central Plains. This presentation is based on his presentation at the MSC Winter Weather Course, December 2002, in Boulder, Colorado. The webcast is accompanied by a case exercise, Inverted Trough Case Exercise.

2014-09-14

406

Optical network-on-chip reconfigurable model for multi-level analysis  

Microsoft Academic Search

Optical network-on-chip (ONoC) is a well accepted emerging technology for use as a communication platform for systems-on-chip (SoC). Its heterogeneous nature dictates developing a hierarchical model and tools for its design and analysis. This paper presents a reconfigurable ONoC model that can be used for analyzing the network at three hierarchical levels: system level, behavioral level, and physical level. At

Atef Allam; Ian O'Connor; Alberto Scandurra

2010-01-01

407

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

NASA Astrophysics Data System (ADS)

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

Chambers, D. P.

2015-03-01

408

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

NASA Astrophysics Data System (ADS)

An efficient perturbational treatment of spin-orbit coupling within the framework of high-level multi-reference techniques has been implemented in the most recent version of the Columbus quantum chemistry package, extending the existing fully variational two-component (2c) multi-reference configuration interaction singles and doubles (MRCISD) method. The proposed scheme follows related implementations of quasi-degenerate perturbation theory (QDPT) model space techniques. Our model space is built either from uncontracted, large-scale scalar relativistic MRCISD wavefunctions or based on the scalar-relativistic solutions of the linear-response-theory-based multi-configurational averaged quadratic coupled cluster method (LRT-MRAQCC). The latter approach allows for a consistent, approximatively size-consistent and size-extensive treatment of spin-orbit coupling. The approach is described in detail and compared to a number of related techniques. The inherent accuracy of the QDPT approach is validated by comparing cuts of the potential energy surfaces of acrolein and its S, Se, and Te analoga with the corresponding data obtained from matching fully variational spin-orbit MRCISD calculations. The conceptual availability of approximate analytic gradients with respect to geometrical displacements is an attractive feature of the 2c-QDPT-MRCISD and 2c-QDPT-LRT-MRAQCC methods for structure optimization and ab inito molecular dynamics simulations.

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

2014-08-01

409

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

410

Control strategy of a solar power inverter (analysis of a fifth order system-II)  

Microsoft Academic Search

To interface solar power inverter structures to the power grid mostly multi-stage filter structures are used for coupling and to fulfil EMI requirements. The resulting topology leads to a high system order, which is difficult to control and problematic to realize due to unknown, unpredictable mains impedance behavior. In this paper a conventional structure is analyzed in detail, giving hints

K. H. Edelmoser; F. A. Himmelstoss

2002-01-01

411

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

SciTech Connect

A multi-scale approach is used to construct a continuum strength model for vanadium. The model is formulated assuming plastic deformation by dislocation motion and strain hardening due to dislocation interactions. Dislocation density is adopted as the state variable in the model. Information from molecular statics, molecular dynamics and dislocation dynamics simulations is combined to create kinetic relations for dislocation motion, strain hardening relations and evolution equations for the dislocation density. Implicit time integration of the constitutive equations is described in the context of implementation in a finite element code. Results are provided illustrating the strain, strain rate, temperature and pressure dependence of the constitutive model.

Lawrence Livermore National Laboratory

2009-08-17

412

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

413

Review of PV Inverter Technology Cost and Performance Projections  

SciTech Connect

The National Renewable Energy Laboratory (NREL) has a major responsibility in the implementation of the U.S. Department of Energy's (DOE's) Solar Energy Technologies Program. Sandia National Laboratories (SNL) has a major role in supporting inverter development, characterization, standards, certifications, and verifications. The Solar Energy Technologies Program recently published a Multiyear Technical Plan, which establishes a goal of reducing the Levelized Energy Cost (LEC) for photovoltaic (PV) systems to $0.06/kWh by 2020. The Multiyear Technical Plan estimates that, in order to meet the PV system goal, PV inverter prices will need to decline to $0.25-0.30 Wp by 2020. DOE determined the need to conduct a rigorous review of the PV Program's technical and economic targets, including the target set for PV inverters. NREL requested that Navigant Consulting Inc.(NCI) conduct a review of historical and projected cost and performance improvements for PV inverters, including identification of critical barriers identified and the approaches government might use to address them.

Navigant Consulting Inc.

2006-01-01

414

Counteracting moment device for reduction of earthquake-induced excursions of multi-level buildings.  

PubMed

A vibration-control mechanism for beams and columns was presented in our previous report in which the earthquake force was transformed into a vibration-control force by using a gear train mechanism. In our previous report, however, only the principle of transforming the earthquake force into the control force was presented; the discussion for real structures and the design method were not presented. The present article provides a theoretical analysis of the column which is used in multi-layered buildings. Experimental tests were carried out for a model of multi-layered buildings in the frequency range of a principal earthquake wave. Theoretical results are compared to the experimental data. The optimal design of the control mechanism, which is of importance in the column design, is presented. Numerical calculations are carried out for the optimal design. It is shown that vibrations of the column involving the mechanism are suppressed remarkably. The optimal design method and the analytical results are applicable to the design of the column. PMID:10335620

Nagaya, K; Fukushima, T; Kosugi, Y

1999-05-01

415

An adaptive framework to differentiate receiving water quality impacts on a multi-scale level.  

PubMed

The paradigm shift in recent years towards sustainable and coherent water resources management on a river basin scale has changed the subject of investigations to a multi-scale problem representing a great challenge for all actors participating in the management process. In this regard, planning engineers often face an inherent conflict to provide reliable decision support for complex questions with a minimum of effort. This trend inevitably increases the risk to base decisions upon uncertain and unverified conclusions. This paper proposes an adaptive framework for integral planning that combines several concepts (flow balancing, water quality monitoring, process modelling, multi-objective assessment) to systematically evaluate management strategies for water quality improvement. As key element, an S/P matrix is introduced to structure the differentiation of relevant 'pressures' in affected regions, i.e. 'spatial units', which helps in handling complexity. The framework is applied to a small, but typical, catchment in Flanders, Belgium. The application to the real-life case shows: (1) the proposed approach is adaptive, covers problems of different spatial and temporal scale, efficiently reduces complexity and finally leads to a transparent solution; and (2) water quality and emission-based performance evaluation must be done jointly as an emission-based performance improvement does not necessarily lead to an improved water quality status, and an assessment solely focusing on water quality criteria may mask non-compliance with emission-based standards. Recommendations derived from the theoretical analysis have been put into practice. PMID:23168645

Blumensaat, F; Tränckner, J; Helm, B; Kroll, S; Dirckx, G; Krebs, P

2013-01-01

416

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

417

An integrated bi-directional power electronic converter with multi-level AC-DC\\/DC-AC converter and non-inverted buck-boost converter for PHEVs with minimal grid level disruptions  

Microsoft Academic Search

In order to increase energy independency and decrease harmful vehicle emissions, plug-in hybrid electric vehicles (PHEVs) have been suggested as viable replacements for conventional internal combustion (IC) vehicles. In the event that PHEVs do command a large market share, their interactions with the grid could either become a large asset or a large burden for the grid, depending on the

Dylan C. Erb; Omer C. Onar; A. Khaligh

2010-01-01

418

Multi-level consistency tests in paleointensity determinations from the welded tuffs of the Aso pyroclastic-flow deposits  

NASA Astrophysics Data System (ADS)

We have performed multi-level consistency tests in an LTD-DHT Shaw paleointensity study on the welded tuffs of the Aso pyroclastic-flow deposits (Aso-1, Aso-2, Aso-3, and Aso-4) in order to obtain reliable mean paleointensities from each unit. For a unit-level consistency test, we collected samples at three or more sites in each unit. To enhance a site-level consistency test, we conducted paleointensity experiments on both whole-rock and glass samples from the same sites. Thermal demagnetization curves of the samples indicate that the main magnetic carrier is titanium-poor titanomagnetite to pure magnetite. Hysteresis parameters are different among the sites of the same units. Also, differences in unblocking spectra and hysteresis parameters are recognized between the whole-rock and glass samples from the same sites. Therefore, these samples of various properties are expected to work effectively for multi-level consistency test. Twenty-nine out of 65 whole-rock samples and 10 out of 31 glass samples gave accepted paleointensity results. At the site-level, consistency of paleointensity estimates is observed with the exception of one site. Two paleointensity estimates from glass samples of a site of Aso-4 are inconsistent and are excluded from further analysis. At the unit-level, consistency or inconsistency among the sites is observed for individual units. For Aso-1, inconsistency in paleointensity estimates among the sites is observed and we can recognize more reliable results from two sites. For Aso-2, consistency in paleointensity estimates from glass and whole-rock samples supports the acceptance of a site. For Aso-3, all paleointensity estimates from two sites are thought to be reliable because consistency between the site-means of the two sites as well as site-level consistency between the glass and whole-rock samples for each site is recognized. For Aso-4, some difference among the sites is observed, but there is no obvious reason to exclude the results of particular sites. Overall, both the site-level and unit-level consistency checks work effectively in these samples which confirm the reliability of the paleointensity estimates or highlights the erroneous ones. On the basis of the reliable paleointensity estimates, unit-mean values are obtained as 24.9 ± 2.2 (1?) ?T (N = 9) for Aso-1, 22.9 ± 1.6 ?T (N = 5) for Aso-2, 28.3 ± 3.4 ?T (N = 10) for Aso-3, and 40.1 ± 6.2 ?T (N = 7) for Aso-4.

Mochizuki, Nobutatsu; Maruuchi, Toru; Yamamoto, Yuhji; Shibuya, Hidetoshi

2013-10-01

419

A multi-level analysis of the relationship between environmental factors and questing Ixodes ricinus dynamics in Belgium  

PubMed Central

Background Ticks are the most important pathogen vectors in Europe. They are known to be influenced by environmental factors, but these links are usually studied at specific temporal or spatial scales. Focusing on Ixodes ricinus in Belgium, we attempt to bridge the gap between current “single-sided” studies that focus on temporal or spatial variation only. Here, spatial and temporal patterns of ticks are modelled together. Methods A multi-level analysis of the Ixodes ricinus patterns in Belgium was performed. Joint effects of weather, habitat quality and hunting on field sampled tick abundance were examined at two levels, namely, sampling level, which is associated with temporal dynamics, and site level, which is related to spatial dynamics. Independent variables were collected from standard weather station records, game management data and remote sensing-based land cover data. Results At sampling level, only a marginally significant effect of daily relative humidity and temperature on the abundance of questing nymphs was identified. Average wind speed of seven days prior to the sampling day was found important to both questing nymphs and adults. At site level, a group of landscape-level forest fragmentation indices were highlighted for both questing nymph and adult abundance, including the nearest-neighbour distance, the shape and the aggregation level of forest patches. No cross-level effects or spatial autocorrelation were found. Conclusions Nymphal and adult ticks responded differently to environmental variables at different spatial and temporal scales. Our results can advise spatio-temporal extents of environment data collection for continuing empirical investigations and potential parameters for biological tick models. PMID:22830528

2012-01-01

420

Gaze constancy in upright and inverted faces.  

PubMed

The dual-route model (Otsuka, Mareschal, Calder, & Clifford, 2014) posits that constancy in the perception of gaze direction across lateral head rotation depends on the integration of information from the eye region and information about head rotation. Incorporation of information about head rotation serves to compensate for the change in eye-region information when viewing a rotated head. We tested the ability of this model to predict the magnitude of Wollaston's effect: When eyes from a frontal pose are inserted into an angled face, the perceived direction of gaze appears attracted towards the direction of the head. The framework of the dual-route model explains Wollaston's effect as a result of the misapplication of this same integration operation without any change in eye-region information. To test this explanation, we compared the magnitude of the integration occurring for Wollaston's effect to that for normal faces. Here, participants performed categorical judgment of gaze direction across head rotation poses in three image conditions: normal face, eyes-only, and Wollaston. Integration of eye and head information was inferred by comparing the effect of pose between the eyes-only condition and the normal face condition, and by examining the effect of pose in the Wollaston condition. Consistent with the dual-route model, the magnitude of integration was similar between the normal face condition and the Wollaston condition. Further, upright and inverted faces yielded similar levels of gaze constancy, showing that the dual-route model applies to the perception of gaze direction in inverted faces as well as in upright faces. PMID:25613759

Otsuka, Yumiko; Mareschal, Isabelle; Clifford, Colin W G

2015-01-01

421

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

422

A multi-level systems approach for the development of tools, equipment and work processes for the construction industry.  

PubMed

Ergonomics is a key issue in the construction industry. Many work tasks and associated equipment and tools are not designed with ergonomics principles in mind. Often, in the development of power tools for construction, any attention to ergonomics is restricted to the human-machine interface and handle design. The need for ergonomics intervention in the development process originates from considerations of safety, health, physical work load, and productivity. It is argued that in each of these respects, the construction industry has lower standards than other industries and therefore has a need and opportunity for improvement. A multi-level ergonomics approach is proposed addressing these issues. The approach defines five levels of ergonomics intervention, from designing individual tools for safety, to designing wider aspects of construction and work flow for optimal productivity. This holistic approach is illustrated using case study examples of the development of power tools and work methods. PMID:15892941

Vedder, Joachim; Carey, Eilís

2005-07-01

423

Concurrent multi-level model for damage evolution in microstructurally debonding composites  

E-print Network

damage model developed in a preceding paper [Raghavan, P., Ghosh, S., 2005. A continuum damage mechanics) level-0 of pure macroscopic analysis using a continuum damage mechanics (CDM) model; (b) level-1; Continuum damage mechanics 1. Introduction Analysis of composite materials with microstruc- tural

Ghosh, Somnath

424

Predictors of Self-Directed Learning for Low-Qualified Employees: A Multi-Level Analysis  

ERIC Educational Resources Information Center

Purpose: This study aims to examine which variables at the level of the individual employee and at the company level are predictors of self-directed learning in low-qualified employees. Methodology: Results were obtained from a sample of 408 low-qualified employees from 35 different companies. The companies were selected from the energy sector,…

Raemdonck, Isabel; van der Leeden, Rien; Valcke, Martin; Segers, Mien; Thijssen, Jo

2012-01-01

425

Multi-temporal, high spatial resolution water level monitoring of the Everglades  

NASA Astrophysics Data System (ADS)

Water level information in South Florida's Everglades is very important for understanding the hydrology of this fragile ecosystem. Currently water levels are determined by a dense stage (water level) network providing high spatial resolution observation. However, because there are a finite number of stage stations in Everglades, water levels in areas located between stage stations can only be estimated by interpolation. Space-borne Interferometric Synthetic Aperture Radar (InSAR) techniques were successfully used to detect high spatial resolution (20-50 meter pixel resolution) water level changes in the Everglades and other wetlands. However, the InSAR observations are relative, providing measure of water level changes (not absolute). In this study we presents a new InSAR technique which enables to estimate a time series of absolute water levels using radar observations acquired successively over the Everglades. In this preliminary stage, we limit our study to Water Conservation Area 1 (WCA1), which is a managed area located in the northern section of the Everglades. The main advantage of the new technique is the reconstruction of absolute water level information instead of previous approaches calculating only relative water level changes. The new technique is called Small Temporal Baseline Subset (STBAS), which utilizes highly coherent interferometric phases obtained only with relatively short time difference between two SAR acquisitions (e.g. 24 or 48 recurrence periods in Radarsat-1 SAR system). The observed interferometric observations have to be calibrated with ground truth data as the reference wetland sheet flow vary daily. We use daily stage data measured at 13 stage stations in WCA1 to calibrate the space-based observations. This information is integrated using the Singular Value Decomposition (SVD) method to generate a time series of absolute water levels. Our calibration-validation study shows a very good fit to the stage data. The correlation coefficient between estimated water levels with STBAS technique and observed stage station data (SITE 7) is 0.99, and the root mean square error (RMSE) of the difference is 5.8 cm. We also developed a new tool, STBAS-viewer that allows an interactive display of water level maps, time series, and water level profiles. This new tool can be very useful for both research and management purposes. Keywords: Wetland interferometric synthetic aperture radar (InSAR), Small temporal baseline subset (STBAS), Absolute water level change, Everglades, Water Construction Area (WCA1).

Hong, S.; Wdowinski, S.; Kim, S.

2008-05-01

426

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

SciTech Connect

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

Ma, Wenjing; Krishnamoorthy, Sriram; Agrawal, Gagan

2011-04-01

427

A Vulcano Expert System: Automatic Alert Level Estimation and GIS Visualization on top of a multi-parameter Data Base  

NASA Astrophysics Data System (ADS)

The success of volcano fast response systems including early warning of an imminent eruption lives through its connection capability to already installed monitoring systems. Also new temporary, possible wireless networks as well as combination of different raw and model data needs to be covered. In practice this means a high-dimensional, complicated (raw or already parameterised) data stream with different sampling rates and time histories that have to be stored and analysed. In the framework of the Exupery project (GEOTECHNOLOGIEN, German Ministry for Education and Research - BMBF) the SeisHub Database handles multi-parameter data resulting from modern volcano monitoring networks simultaneously. This is a quite common situation today in order to assess volcanic activity. The warning system, here a GIS and an automatic alert level estimation, connects to the data base to retrieve the relevant information. The GIS provides access to the data as well as analysis results. By overlaying various parameters in the GIS systems the expert can analyse the situation and base his/her decision easily on multi-parameter data. In addition to data interactive visualization via the GIS the alert level of the volcano is automatically estimated using a Bayesian Belief Network (BBN) approach. This allows the expert to verify his own assessment versus the automatic system. In case there are major differences, the expert can identify the origin of the difference in the graphical representation of the BBN and if necessary adapt the BBN. BBNs are chosen because of their transparency (graphical representation), flexibility, probabilistic architecture and their possibility to incorporate expert knowledge. The probabilistic architecture allows to compute a confidence measure for the given alert level. A high, automatically estimated alert level with either high or low confidence can certainly lead to different decisions by the human interpreter.

Beyreuther, Moritz; Barsch, Robert; Bernsdorf, Stefan; Zakšek, Klemen; Wassermann, Joachim

2010-05-01

428

Multi-decadal sea level fluctuations in the North Pacific based on the historical ocean hydrographic data  

NASA Astrophysics Data System (ADS)

Using a historical ocean hydrographic data, decadal to multi-decadal baroclinic sea level changes from 1951 to 2007 in the North Pacific are investigated. The fluctuations of the baroclinic sea level anomalies are decomposed to the first baroclinic mode and the rest, considering two oceanic physical processes: dynamical response of the main pycnocline to wind forcing and steric contribution of substantial water mass density change in the upper ocean. The first baroclinic sea level change exhibits the changes in the subtropical gyre in the North Pacific as suggested by previous studies. The sea level change around the Kuroshio Extension (KE) has bi-decadal and penta-decadal fluctuations, which are mainly explained as the first baroclinic response to the basin-scale wind stress change. In addition to this, the rest of baroclinic modes are not negligible around the KE recirculation region over penta-decadal fluctuation. This fluctuation results from mainly density change of the upper ocean, which is consistent with the heat transport change due to the changes in the strength of the Kuroshio and the KE shown in the first mode. The fluctuations of the composite of the rest modes are also dominant in the central North Pacific, in which ocean surface heat flux plays an important role. These sea level changes affect ocean surface currents as well as that in the first mode.

Suzuki, T.; Ishii, M.

2012-12-01

429

Challenges and opportunities for inverters in microgrids  

Microsoft Academic Search

Microgrids are local low voltage power systems that offer many advantages over grid power in terms of security, power autonomy and the ability to incorporate distributed generation, including renewable energy. In low voltage AC microgrids the use of renewable energy requires DC to AC conversion using inverters. With a large number of inverters in a microgrid, there are issues relating

David Cornforth; Tim Moore; Saad Sayeef

2011-01-01

430

Inverted File Compression through Document Identifier Reassignment.  

ERIC Educational Resources Information Center

Discusses the use of inverted files in information retrieval systems and proposes a document identifier reassignment method to reduce the average gap values in an inverted file. Highlights include the d-gap technique; document similarity; heuristic algorithms; file compression; and performance evaluation from a simulation environment. (LRW)

Shieh, Wann-Yun; Chen, Tien-Fu; Shann, Jean Jyh-Jiun; Chung, Chung-Ping

2003-01-01

431

Reliability and maintainability in photovoltaic inverter design  

Microsoft Academic Search

The renewable energy market is booming due to the shortage of conventional energies and the requirement of environment protection. A large number of PV systems are being installed throughout the world. The PV inverter is a critical sub-system in the PV system. To increase availability and secure maximum return on investment, a PV system requires high PV inverter reliability to

Zhiqiang Janet Ma; Spyros Thomas

2011-01-01

432

INVERTIBILITY OF SOBOLEV MAPPINGS UNDER MINIMAL HYPOTHESES  

E-print Network

INVERTIBILITY OF SOBOLEV MAPPINGS UNDER MINIMAL HYPOTHESES LEONID V. KOVALEV, JANI ONNINEN, AND KAI, finite distortion. Kovalev was supported by the NSF grant DMS­0913474. Onninen was supported by the NSF LEONID V. KOVALEV, JANI ONNINEN, AND KAI RAJALA Jacobian [15, Example 18]. To quantify the invertibility

Jyväskylä, University of

433

Circuit controls transients in SCR inverters  

NASA Technical Reports Server (NTRS)

Elimination of starting difficulties in SCR inverters is accomplished by the addition of two taps of the output winding of the inverter. On starting or under transient loads, the two additional taps deliver power through diodes without requiring quenching of SCR currents in excess of normal starting load.

Moore, E. T.; Wilson, T. G.

1964-01-01

434

Inverters for interfacing of solar cells with the power grid  

Microsoft Academic Search

In this work, based on a research course in the Engineering Dep. Cambridge University, some non-classical inverter circuits are studied. They can be used for interfacing solar cells with the power grid at low voltage (230V) and at low power level. They are based on d.c. choppers which have a fast switching transistor. Their theoretical efficiency is 100 percent and

G. N. Karamanzanis; R. D. Jackson

1984-01-01

435

High-level synthesis with multi-objective genetic algorithm: A comparative encoding analysis  

Microsoft Academic Search

The high-level synthesis process involves three interdependent and NP-complete optimization problems: (i) the operation scheduling, (ii) the resource allocation, and (iii) the controller synthesis. Evolutionary algorithms have been effectively applied to high level synthesis in presence conflicting design objectives for finding good tradeoffs in the design space. However, so far the design space exploration has been performed using single-objective evolutionary

Christian Pilato; Daniele Loiacono; Fabrizio Ferrandi; Pier Luca Lanzi; Donatella Sciuto

2008-01-01

436

Multi-level magmatic system of El Hierro Island (Canary Islands) constrained by multi-satellite radar interferometry measurements during the 2011-2012 eruption  

NASA Astrophysics Data System (ADS)

Starting from July 2011, anomalous seismicity was observed at El Hierro Island (Canary Islands, Spain). During the following three months, seismic activity increased both in number of events and in magnitude, while expanding over a large area. In early October 2011 the process led to a submarine eruption, with some uncertainty about the location and timing of vent(s) opening. The site of the eruption was ~10 km from the initial and main earthquake loci, indicative of significant lateral migration. Here, we conduct a multi-frequency, multi-sensor interferometric analysis of space-borne radar images acquired using three different satellites (Radarsat-2, ASAR-ENVISAT and COSMO-SkyMed). Radar interferometry is used to measure the deformation that occurred from December 2009 to July 2012. InSAR data fully captures both the pre-, co- and post-eruptive phases. Subsequently, elastic modeling of the ground deformation is employed to constrain the dynamics associated with the magmatic and eruptive activity. This study represents one of the first geodetically-constrained active magmatic plumbing system model for any of the Canary Islands volcanoes, and one of the few examples of geodetic measurement of submarine volcanic activity to date. It reveals a complex magmatic system with multiple levels of stagnation, a deeper central system (~8.5 km depth) and a shallower magma reservoir at the flank of the southern rift (~4 km depth). Before eruption, magma propagated ~5 km downrift towards the eruption fissure. From mid-November 2011 to early January 2012 the system was continuously recharged from source(s) deeper than 10 km, which contributed to a relatively atypical long duration for a basaltic eruption (~5 months). The submarine eruption finished on early March 2012. However, on June 24, 2012 the seismic activity resumed and intense ground deformation has been recorded. The anomalous seismicity continued for a month depicting a clear, but different migration path with respect to the previous period. At the time of the writing of this abstract (early August 2012), the activity has subsided. The most recently acquired InSAR (Radarsat-2 and COSMO-SkyMed) data will be presented and interpreted. The El Hierro Island magmatic plumbing system is a much more complex system that previously believed. It is composed with at least three main stagnation levels, i) a petrologically-constrained level at 20-26 km depth, ii) a level at the moho, base of the oceanic crust at 8-12 km depth, and iii) a 4 km depth level at the base of the volcanic edifice, coinciding with the typical seafloor depth at El Hierro region. Acknowledgments: Our research was supported by an Ontario Early Researcher Award, the CSRN NSERC Strategic Network Grant, and the NSERC, and the Banting Postdoctoral Fellowship. Additional support was provided by the Spanish MICINN project AYA2010-17448, and the Moncloa Campus of Excellence (UCM-UPM, CSIC). Data was provided by ESA (European Space Agency) through project CAT1:6745; CSA (Canadian Space Agency) by SOAR-E project #28209; and ASI (Italian Space Agency) SAR4Volcanoes project (agreement I/034/11/0).

Gonzalez, P. J.; Samsonov, S. V.; Pepe, S.; Tiampo, K. F.; Tizzani, P.; Fernandez, J.; Sansosti, E.

2012-12-01

437

The evolutionary impact of androgen levels on prostate cancer in a multi-scale mathematical model  

PubMed Central

Background Androgens bind to the androgen receptor (AR) in prostate cells and are essential survival factors for healthy prostate epithelium. Most untreated prostate cancers retain some dependence upon the AR and respond, at least transiently, to androgen ablation therapy. However, the relationship between endogenous androgen levels and cancer etiology is unclear. High levels of androgens have traditionally been viewed as driving abnormal proliferation leading to cancer, but it has also been suggested that low levels of androgen could induce selective pressure for abnormal cells. We formulate a mathematical model of androgen regulated prostate growth to study the effects of abnormal androgen levels on selection for pre-malignant phenotypes in early prostate cancer development. Results We find that cell turnover rate increases with decreasing androgen levels, which may increase the rate of mutation and malignant evolution. We model the evolution of a heterogeneous prostate cell population using a continuous state-transition model. Using this model we study selection for AR expression under different androgen levels and find that low androgen environments, caused either by low serum testosterone or by reduced 5?-reductase activity, select more strongly for elevated AR expression than do normal environments. High androgen actually slightly reduces selective pressure for AR upregulation. Moreover, our results suggest that an aberrant androgen environment may delay progression to a malignant phenotype, but result in a more dangerous cancer should one arise. Conclusions The model represents a useful initial framework for understanding the role of androgens in prostate cancer etiology, and it suggests that low androgen levels can increase selection for phenotypes resistant to hormonal therapy that may also be more aggressive. Moreover, clinical treatment with 5?-reductase inhibitors such as finasteride may increase the incidence of therapy resistant cancers. Reviewers This article was reviewed by Ariosto S. Silva (nominated by Marek Kimmel) and Marek Kimmel. PMID:20406442

2010-01-01

438

Nanostructured Inverted Organic Photovoltaic Cells  

NASA Astrophysics Data System (ADS)

Organic photovoltaic cells (OPVs)are promising devices for inexpensive power generation from sunlight. Organic semiconductors, the basic materials for OPVs, can be fabricated using a broad range of fabrication technologies from vapor deposition to solution processing. Upon light absorption, a strongly bound exciton is generated which can diffuse to a donor-acceptor heterojunction. At this interface it can be dissociated into free charge carriers which can be collected by the device electrodes. A major challenge for OPVs are short exciton diffusion lengths of up to 20 nm. Morphology engineering is required in order to harvest the exciton before it recombines and improve OPV performance. This work focuses on the study of nanostructured morphologies for use in inverted architecture OPVs. Glancing angle deposition (GLAD)is employed to fabricate nanocolumnar acceptor films. Through combining these nanostructured C60 films with a conjugated polymer donor P3CBT and a small molecule 3-Q, inverted OPVs are fabricated with the goal to analyze effect of morphology engineering on device performance. A major challenge was that C60 were found to be soluble in most commonly used organic solvents such as dichlorobenzene or chloroform. Although this challenge has limited the donor choice and therefore has limited device performance, a significant effect of morphology engineering could be observed. All GLAD structured C60 OPVs outperformed state of the art architectures such as planar films and bulk heterojunctions fabricated with the same materials. For P3CBT in particular the GLAD structured devices exhibited a twofold increase in power conversion efficiency compared with bulk heterojunctions and a fourfold increase compared with planar devices. In a further study, the acceptor materials PTCDA and C60 were co-evaporated into a single film. PTCDA is stable against non-polar organic solvents while C60 provides a high electron mobility. Nanocolumnar acceptor blended PTCDA:C60 films were proven to remain stable when treated with dichlorobenzene. Furthermore, optical and electronic properties of these acceptor blends were investigated.

Thomas, Michael

439

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

440

A multilevel voltage-source inverter with separate DC sources for static VAr generation  

Microsoft Academic Search

A new multilevel voltage-source inverter with 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

Fang Zheng Peng; Jih-Sheng Lai; John McKeever; J. VanCoevering

1995-01-01

441

A multilevel voltage-source inverter with separate DC sources for static VAr generation  

Microsoft Academic Search

A new multilevel voltage-source inverter with 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

Fang Zheng Peng; Jih-Sheng Lai; J. W. McKeever; J. VanCoevering

1996-01-01

442

The generalized discontinuous PWM scheme for three-phase voltage source inverters  

Microsoft Academic Search

This paper presents analytical techniques for the determination of the expressions for the modulation signals used in the carrier-based sinusoidal and generalized discontinuous pulse-width modulation schemes for two-level, three-phase voltage source inverters. The proposed modulation schemes are applicable to inverters generating balanced or unbalanced phase voltages. Some results presented in this paper analytically generalize the several expressions for the modulation

Olorunfemi Ojo

2004-01-01

443

A novel vector control scheme for transistor PWM inverter-fed induction motor drive  

Microsoft Academic Search

A novel vector control scheme for a transistor pulse-width-modulation (PWM)-inverter-fed induction motor drive is presented. The system is based on a current control loop that consists of two independent nonlinear controllers that regulate the DC (field-oriented) components of the stator current vector. Three-level hysteresis comparators are used as current controllers. The outputs of the comparators select the appropriate inverter output

Marian P. Kazmierkowski; Waldemar Sulkowski

1991-01-01

444

Inverted Alu repeats unstable in yeast are excluded from the human genome.  

PubMed

The nearly one million ALU: repeats in human chromosomes are a potential threat to genome integrity. ALU:s form dense clusters where they frequently appear as inverted repeats, a sequence motif known to cause DNA rearrangements in model organisms. Using a yeast recombination system, we found that inverted ALU: pairs can be strong initiators of genetic instability. The highly recombinagenic potential of inverted ALU: pairs was dependent on the distance between the repeats and the level of sequence divergence. Even inverted ALU:s that were 86% homologous could efficiently stimulate recombination when separated by <20 bp. This stimulation was independent of mismatch repair. Mutations in the DNA metabolic genes RAD27 (FEN1), POL3 (polymerase delta) and MMS19 destabilized widely separated and diverged inverted ALU:s. Having defined factors affecting inverted ALU: repeat stability in yeast, we analyzed the distribution of ALU: pairs in the human genome. Closely spaced, highly homologous inverted ALU:s are rare, suggesting that they are unstable in humans. ALU: pairs were identified that are potential sites of genetic change. PMID:10899135

Lobachev, K S; Stenger, J E; Kozyreva, O G; Jurka, J; Gordenin, D A; Resnick, M A

2000-07-17

445

Inverted Alu repeats unstable in yeast are excluded from the human genome  

PubMed Central

The nearly one million Alu repeats in human chromosomes are a potential threat to genome integrity. Alus form dense clusters where they frequently appear as inverted repeats, a sequence motif known to cause DNA rearrangements in model organisms. Using a yeast recombination system, we found that inverted Alu pairs can be strong initiators of genetic instability. The highly recombinagenic potential of inverted Alu pairs was dependent on the distance between the repeats and the level of sequence divergence. Even inverted Alus that were 86% homologous could efficiently stimulate recombination when separated by <20 bp. This stimulation was independent of mismatch repair. Mutations in the DNA metabolic genes RAD27 (FEN1), POL3 (polymerase ?) and MMS19 destabilized widely separated and diverged inverted Alus. Having defined factors affecting inverted Alu repeat stability in yeast, we analyzed the distribution of Alu pairs in the human genome. Closely spaced, highly homologous inverted Alus are rare, suggesting that they are unstable in humans. Alu pairs were identified that are potential sites of genetic change. PMID:10899135

Lobachev, Kirill S.; Stenger, Judith E.; Kozyreva, Olga G.; Jurka, Jerzy; Gordenin, Dmitry A.; Resnick, Michael A.

2000-01-01

446

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

447

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

448

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

PubMed Central

Humans are fundamentally social. They form societies which consist of hierarchically layered nested groups of various quality, size, and structure. The anthropologic literature has classified these groups as support cliques, sympathy groups, bands, cognitive groups, tribes, linguistic groups, and so on. Anthropologic data show that, on average, each group consists of approximately three subgroups. However, a general understanding of the structural dependence of groups at different layers is largely missing. We extend these early findings to a very large high-precision large-scale internet-based social network data. We analyse the organisational structure of a complete, multi-relational, large social multiplex network of a human society consisting of about 400,000 odd players of an open-ended massive multiplayer online game for which we know all about their various group memberships at different layers. Remarkably, the online players' society exhibits the same type of structured hierarchical layers as found in hunter-gatherer societies. Our findings suggest that the hierarchical organisation of human society is deeply nested in human psychology. PMID:25283998

Fuchs, Benedikt; Sornette, Didier; Thurner, Stefan

2014-01-01

449

Retrieval of tea polyphenol at leaf level using spectral transformation and multi-variate statistical approach  

NASA Astrophysics Data System (ADS)

In the present study, field based hyperspectral data was used to estimate the tea (Camellia sinensis L.) polyphenol at Deha Tea garden of Assam state, India. Leaf reflectance spectra were first filtered for noise and then transformed into normalized and first derivative reflectance for further analysis. Stepwise discriminant analysis was carried out to select sensitive bands for a range of polyphenol concentration by minimizing the effects of other factors such as age of the bushes and management practices. The wavelengths at 358, 369, 484, 845, 916, 1387, 1420, 1435, 1621 and 2294 nm were identified as sensitive to tea polyphenol, among which 2294 nm was found to be the most recurring band. The noise removed selected bands, their transformed derivatives and principal components were regressed with the tea polyphenol using univariate and multi-variate analysis. In univariate analysis the correlation was very poor with RMSE more than 3.0. A significant improvement in R2 values were observed when multivariate analyses like stepwise multiple linear regression (SMLR) and partial least square regression (PLSR) was carried out. The PLSR of first derivative reflectance was most accurate (R2 = 0.81 and RMSE = 1.39 mg g-1) among all the uni- and multivariate analysis for predicting the polyphenol of fresh tea leaves.

Dutta, Dibyendu; Das, Prabir Kumar; Bhunia, Uttam Kumar; Singh, Upasana; Singh, Shalini; Sharma, Jaswant Raj; Dadhwal, Vinay Kumar

2015-04-01

450

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

NASA Astrophysics Data System (ADS)

Humans are fundamentally social. They form societies which consist of hierarchically layered nested groups of various quality, size, and structure. The anthropologic literature has classified these groups as support cliques, sympathy groups, bands, cognitive groups, tribes, linguistic groups, and so on. Anthropologic data show that, on average, each group consists of approximately three subgroups. However, a general understanding of the structural dependence of groups at different layers is largely missing. We extend these early findings to a very large high-precision large-scale internet-based social network data. We analyse the organisational structure of a complete, multi-relational, large social multiplex network of a human society consisting of about 400,000 odd players of an open-ended massive multiplayer online game for which we know all about their various group memberships at different layers. Remarkably, the online players' society exhibits the same type of structured hierarchical layers as found in hunter-gatherer societies. Our findings suggest that the hierarchical organisation of human society is deeply nested in human psychology.

Fuchs, Benedikt; Sornette, Didier; Thurner, Stefan

2014-10-01

451

Sensitivity of Aerosol Multi-Sensor Daily Data Intercomparison to the Level 3 Dataday Definition  

NASA Technical Reports Server (NTRS)

Topics include: why people use Level 3 products, why someone might go wrong with Level 3 products, differences in L3 from different sensors, Level 3 data day definition, MODIS vs. MODIS, AOD MODIS Terra vs. Aqua in Pacific, AOD Aqua MODIS vs. MISR correlation map, MODIS vs MISR on Terra, MODIS atmospheric data day definition, orbit time difference for Terra and Aqua 2009-01-06, maximum time difference for Terra (Calendar day), artifact explains, data day definitions, local time distribution, spatial (local time) data day definition, maximum time difference between Terra and Aqua, Removing the artifact in 16-day AOD correlation, MODIS cloud top pressure, and MODIS Terra and Aqua vs. AIRS cloud top pressure.

Leptoukh, Gregory; Lary, David; Shen, Suhung; Lynnes, Christopher

2010-01-01

452

The learner’s perspective in GP teaching practices with multi-level learners: a qualitative study  

PubMed Central

Background Medical students, junior hospital doctors on rotation and general practice (GP) registrars are undertaking their training in clinical general practices in increasing numbers in Australia. Some practices have four levels of learner. This study aimed to explore how multi-level teaching (also called vertical integration of GP education and training) is occurring in clinical general practice and the impact of such teaching on the learner. Methods A qualitative research methodology was used with face-to-face, semi-structured interviews of medical students, junior hospital doctors, GP registrars and GP teachers in eight training practices in the region that taught all levels of learners. Interviews were audio-recorded and transcribed. Qualitative analysis was conducted using thematic analysis techniques aided by the use of the software package N-Vivo 9. Primary themes were identified and categorised by the co-investigators. Results 52 interviews were completed and analysed. Themes were identified relating to both the practice learning environment and teaching methods used. A practice environment where there is a strong teaching culture, enjoyment of learning, and flexible learning methods, as well as learning spaces and organised teaching arrangements, all contribute to positive learning from a learners’ perspective. Learners identified a number of innovative teaching methods and viewed them as positive. These included multi-level learner group tutorials in the practice, being taught by a team of teachers, including GP registrars and other health professionals, and access to a supernumerary GP supervisor (also termed “GP consultant teacher”). Other teaching methods that were viewed positively were parallel consulting, informal learning and rural hospital context integrated learning. Conclusions Vertical integration of GP education and training generally impacted positively on all levels of learner. This research has provided further evidence about the learning culture, structures and teaching processes that have a positive impact on learners in the clinical general practice setting where there are multiple levels of learners. It has also identified some innovative teaching methods that will need further examination. The findings reinforce the importance of the environment for learning and learner centred approaches and will be important for training organisations developing vertically integrated practices and in their training of GP teachers. PMID:24645670

2014-01-01

453

The role of school and individual differences in the academic attainment of learners with special educational needs and disabilities: a multi-level analysis  

Microsoft Academic Search

Students with special educational needs and disabilities (SEND) are at a greatly increased risk of poor academic outcomes. Understanding the factors that influence their attainment is a crucial first step towards developing more effective provision. In the current study we present a multi-level, natural variation analysis which highlights important determinants at school and individual levels in two core academic subjects

Neil Humphrey; Michael Wigelsworth; Alexandra Barlow; Garry Squires

2012-01-01

454

Multi-Level Testing In a Net-Centric Environment Interoperability or lack thereof, is the characteristic that highlights the fact that systems  

E-print Network

Multi-Level Testing In a Net-Centric Environment Interoperability or lack thereof testing in net-centric environments including that of the SOA over the Global Information Grid (GIG). We of increased rigor and faster test development in a net-centric environment. Levels of Information Systems

455

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

456

Exploiting Multi-level Parallelism for Homology Search using General Purpose Xiandong Meng  

E-print Network

for sequence homology database searches. The results show that the classic Smith Waterman sequence alignment method such as the Needleman-Wunsch [16] and Smith-Waterman algorithms [20], provide optimal solutions level of sensitivity for similarity searching at high speed. OSEARCH and SSEARCH [18] are two Smith

Chaudhary, Vipin

457

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

458

Batch-assembled multi-level micromachined mechanisms from bulk silicon  

Microsoft Academic Search

The authors report on the development of a new technology intended for the wafer level fabrication and assembly of fully integrated micromechanisms. The technology is based on a boron-doped bulk silicon dissolved wafer process that has been used to fabricate a variety of micromechanical devices. The overall process utilizes three wafers: two silicon and one glass. All the major mechanical

Y. Gianchandani; K. Najafi

1992-01-01

459

Batch fabrication and assembly of micromotor-driven mechanisms with multi-level linkages  

Microsoft Academic Search

The development of a new technology for the wafer-level fabrication and assembly of fully integrated mechanisms is reported. It is based on a boron-doped bulk silicon dissolved wafer process that has been used to fabricate a variety of micromechanical devices. The overall process consists of three wafers, two silicon and one glass. The first silicon wafer is processed to create

Yogesh Gianchandani; Khalil Najafi

1992-01-01

460

Acoustic scattering solver based on single level FMM for multi-GPU systems  

Microsoft Academic Search

In this paper, we present a heterogeneous parallel solver of a high frequency single level Fast Multipole Method (FMM) for the Helmholtz equation applied to acoustic scattering. The developed solution uses multiple GPUs to tackle the compute bound steps of the FMM (aggregation, disaggregation, and near interactions) while the CPU handles a memory bound step (translation) using OpenMP. The proposed

Miguel López-Portugués; Jesús A. López-Fernández; Jonatan Menéndez-Canal; Alberto Rodríguez-Campa; José Ranilla