Open Access. Powered by Scholars. Published by Universities.®
- Institution
- Publication
- Publication Type
Articles 1 - 12 of 12
Full-Text Articles in Entire DC Network
Improved Quantification Of Small Objects In Near-Infrared Diffuse Optical Tomography, Subhadra Srinivasan, Brian W. Pogue, Hamid Dehghani, Shudong Jiang, Xiaomei Song, Keith D. Paulsen
Improved Quantification Of Small Objects In Near-Infrared Diffuse Optical Tomography, Subhadra Srinivasan, Brian W. Pogue, Hamid Dehghani, Shudong Jiang, Xiaomei Song, Keith D. Paulsen
Dartmouth Scholarship
Diffuse optical tomography allows quantification of hemoglobin, oxygen saturation, and water in tissue, and the fidelity in this quantification is dependent on the accuracy of optical properties determined during image reconstruction. In this study, a three-step algorithm is proposed and validated that uses the standard Newton minimization with Levenberg-Marquardt regularization as the first step. The second step is a modification to the existing algorithm using a two-parameter regularization to allow lower damping in a region of interest as compared to background. This second stage allows the recovery of the actual size of an inclusion. A region-based reconstruction is the final …
Integrated Coverage And Connectivity Configuration For Energy Conservation In Sensor Networks, Guoliang Xing, Xiaorui Wang, Yuanfang Zhang, Chenyang Lu, Robert Pless, Christopher Gill
Integrated Coverage And Connectivity Configuration For Energy Conservation In Sensor Networks, Guoliang Xing, Xiaorui Wang, Yuanfang Zhang, Chenyang Lu, Robert Pless, Christopher Gill
All Computer Science and Engineering Research
An effective approach for energy conservation in wireless sensor networks is scheduling sleep intervals for extraneous nodes, while the remaining nodes stay active to provide continuous service. For the sensor network to operate successfully, the active nodes must maintain both sensing coverage and network connectivity. Fur-thermore, the network must be able to configure itself to any feasible degrees of coverage and connectivity in order to support different applications and environments with diverse requirements. This paper presents the design and analysis of novel protocols that can dynamically configure a network to achieve guaranteed degrees of coverage and connectivity. This work differs …
A Three-Dimensional Fdtd Subgridding Algorithm Based On Interpolation Of Current Density, Kai Xiao, David Pommerenke, James L. Drewniak
A Three-Dimensional Fdtd Subgridding Algorithm Based On Interpolation Of Current Density, Kai Xiao, David Pommerenke, James L. Drewniak
Electrical and Computer Engineering Faculty Research & Creative Works
A three-dimensional subgridding algorithm for the finite difference time domain (FDTD) method is proposed in this paper. The method is based on interpolation of electric and magnetic current densities. The coarse-fine mesh ratio can be either 1:2 or 1:3. Results of a test model utilizing a lossless cavity excited with a dipole show no tendency of instability after 500000 time steps. The reflection in time domain at the subgridding interface was calculated to test the accuracy of the subgridding algorithm.
An Extrapolation Procedure To Shorten Time Domain Simulations, Giuseppe Selli, James L. Drewniak, David Pommerenke
An Extrapolation Procedure To Shorten Time Domain Simulations, Giuseppe Selli, James L. Drewniak, David Pommerenke
Electrical and Computer Engineering Faculty Research & Creative Works
Time-domain simulation algorithms are widely used in the anaylsis and design of electromagnetic systems. Many of them are characterized by high Q's. Thus, the simulations have to employ many time steps in order to achieve a complete characterization of these systems. This time-consuming computational effort can be avoided if the late instants of time are extrapolated by applying a parametric estimation algorithm. An optimized implementation of a time-domain extrapolation method and a stop criterion are discussed in this paper. The latter criterion is based upon a normalized squared difference between the waveforms extrapolated from two different sets of initial data …
Identifying Variable-Length Meaningful Phrases With Correlation Functions, Hyoung-Rae Kim, Philip K. Chan
Identifying Variable-Length Meaningful Phrases With Correlation Functions, Hyoung-Rae Kim, Philip K. Chan
Electrical Engineering and Computer Science Faculty Publications
Finding meaningful phrases in a document has been studied in various information retrieval systems in order to improve the performance. Many previous statistical phrase finding methods had different aim such as document classification. Some are hybridized with statistical and syntactic grammatical methods; others use correlation heuristics between words. We propose a new phrase-finding algorithm that adds correlated words one by one to the phrases found in the previous stage, maintaining high correlation within a phrase. Our results indicate that our algorithm finds more meaningful phrases than an existing algorithm. Furthermore, the previous algorithm could be improved by applying different correlation …
Fault Localization In Reversible Circuits Is Easier Than For Classical Circuits, Kavitha Ramasamy, Radhika Tagare, Edward Perkins, Marek Perkowski
Fault Localization In Reversible Circuits Is Easier Than For Classical Circuits, Kavitha Ramasamy, Radhika Tagare, Edward Perkins, Marek Perkowski
Electrical and Computer Engineering Faculty Publications and Presentations
There is recently an interest in test generation for reversible circuits, but nothing has been published about fault localization in such circuits. This paper deals with fault localization for binary reversible (permutative) circuits. We concentrate on functional test based fault localization, to detect and locate “stuck-at” faults in a reversible circuit by creating an adaptive tree. A striking property of reversible circuits is that they exhibit “symmetric” adaptive trees. This helps considerably by being able to generate only half of the tree, and the other half is created as the mirror image of the first half. Because each test covers …
Testing Layered Interconnection Networks, Bin Liu, Fabrizio Lombardi, Nohpill Park, Minsu Choi
Testing Layered Interconnection Networks, Bin Liu, Fabrizio Lombardi, Nohpill Park, Minsu Choi
Electrical and Computer Engineering Faculty Research & Creative Works
We present an approach for fault detection in layered interconnection networks (LINs). An LIN is a generalized multistage interconnection network commonly used in reconfigurable systems; the nets (links) are arranged in sets (referred to as layers) of different size. Switching elements (made of simple switches such as transmission-gate-like devices) are arranged in a cascade to connect pairs of layers. The switching elements of an LIN have the same number of switches, but the switching patterns may not be uniform. A comprehensive fault model for the nets and switches is assumed at physical and behavioral levels. Testing requires configuring the LIN …
Autonomous Control Of A Scale Model Of A Trailer-Truck Using An Obstacle-Avoidance Path-Planning Hierarchy, Robert S. Woodley, Levent Acar
Autonomous Control Of A Scale Model Of A Trailer-Truck Using An Obstacle-Avoidance Path-Planning Hierarchy, Robert S. Woodley, Levent Acar
Electrical and Computer Engineering Faculty Research & Creative Works
A scale model of a tractor-trailer truck was developed as a testbed for control algorithms. The truck operates in autonomous or semi-autonomous modes. An on-board Pentium computer with a PC104 bus performs the computations and data collection. Various sensors and a wireless transceiver are on-board the truck. Our research focus has been in the autonomous control of vehicles using intelligent systems. For this document we have employed a multi-resolutional hierarchy to plan a path for the tractor-trailer truck. The hierarchy starts with a simple path then warps it around obstacles. The modular construction of the hierarchy allows more intelligent agents …
Dynamic Shared State Maintenance In Distributed Virtual Environments, Felix George Hamza-Lup
Dynamic Shared State Maintenance In Distributed Virtual Environments, Felix George Hamza-Lup
Electronic Theses and Dissertations
Advances in computer networks and rendering systems facilitate the creation of distributed collaborative environments in which the distribution of information at remote locations allows efficient communication. Particularly challenging are distributed interactive Virtual Environments (VE) that allow knowledge sharing through 3D information. In a distributed interactive VE the dynamic shared state represents the changing information that multiple machines must maintain about the shared virtual components. One of the challenges in such environments is maintaining a consistent view of the dynamic shared state in the presence of inevitable network latency and jitter. A consistent view of the shared scene will significantly increase …
Quantum Lattice Representation Of Dark Solitons, George Vahala, Linda L. Vahala, Jeffrey Yepez
Quantum Lattice Representation Of Dark Solitons, George Vahala, Linda L. Vahala, Jeffrey Yepez
Electrical & Computer Engineering Faculty Publications
The nonlinear Schrodinger (NLS) equation in a self-defocusing Kerr medium supports dark solitons. Moreover the mean field description of a dilute Bose-Einstein condensate (BEC) is described by the Gross-Pitaevskii equation, which for a highly anisotropic (cigar-shaped) magnetic trap reduces to a one-dimensional (1D) cubic NLS in an external potential. A quantum lattice algorithm is developed for the dark solitons. Simulations are presented for both black (stationary) solitons as well as (moving) dark solitons. Collisions of dark solitons are compared with the exact analytic solutions and coupled dark-bright vector solitons are examined. The quantum algorithm requires 2 qubits per scalar field …
Including Organizational Cultural Parameters In Work Processes, Holly A. H. Handley, Nancy J. Heacox
Including Organizational Cultural Parameters In Work Processes, Holly A. H. Handley, Nancy J. Heacox
Engineering Management & Systems Engineering Faculty Publications
Recent work in modeling decision-making work processes has focused on including the national culture of individual decision-makers in order to emphasize the differences in decision criteria between decision-makers of different nationalities. In addition to nationality, a decision-maker is also a member of an organization and brings this organizational culture to his role in the work process, where it may also affect his task performance. In order to represent the organizational impact on the work process, five organizational cultural parameters were identified and included in an algorithm for modeling and simulation of cultural difference in human decision-making. While the five modifiers …
Boost Integrated Push-Pull Rectifier With Power Factor Correction And Output Voltage Regulation Using A New Digital Control Technique, Zhong Nie, Mehdi Ferdowsi, Ali Emadi
Boost Integrated Push-Pull Rectifier With Power Factor Correction And Output Voltage Regulation Using A New Digital Control Technique, Zhong Nie, Mehdi Ferdowsi, Ali Emadi
Electrical and Computer Engineering Faculty Research & Creative Works
An integrated converter is a synthesized converter based on the overall system integration, which is simplified by the system objective and can implement the system functions similar to the discrete converters. An integrated converter consists of converter sets; each converter set has a special function defined by the designer. A family of DC/DC Boost based integrated rectifiers with two active switches can be derived by the integration concept. In this paper, Boost + Push-Pull integrated converter is introduced and derived. To regulate the output voltage and shape the input current, a new simple digital control method is applied. In contrast …