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Articles 1 - 13 of 13
Full-Text Articles in Engineering
H-Infinity Estimation For Fuzzy Membership Function Optimization, Daniel J. Simon
H-Infinity Estimation For Fuzzy Membership Function Optimization, Daniel J. Simon
Electrical and Computer Engineering Faculty Publications
Given a fuzzy logic system, how can we determine the membership functions that will result in the best performance? If we constrain the membership functions to a specific shape (e.g., triangles or trapezoids) then each membership function can be parameterized by a few variables and the membership optimization problem can be reduced to a parameter optimization problem. The parameter optimization problem can then be formulated as a nonlinear filtering problem. In this paper we solve the nonlinear filtering problem using H∞ state estimation theory. However, the membership functions that result from this approach are not (in general) sum normal. …
Dynamic Voltage Scaling Techniques For Power Efficient Video Decoding, Ben Lee, Eriko Nurvitadhi, Reshma Dixit, Chansu Yu, Myungchul Kim
Dynamic Voltage Scaling Techniques For Power Efficient Video Decoding, Ben Lee, Eriko Nurvitadhi, Reshma Dixit, Chansu Yu, Myungchul Kim
Electrical and Computer Engineering Faculty Publications
This paper presents a comparison of power-aware video decoding techniques that utilize dynamic voltage scaling (DVS). These techniques reduce the power consumption of a processor by exploiting high frame variability within a video stream. This is done through scaling of the voltage and frequency of the processor during the video decoding process. However, DVS causes frame deadline misses due to inaccuracies in decoding time predictions and granularity of processor settings used. Four techniques were simulated and compared in terms of power consumption, accuracy, and deadline misses. In addition, this paper proposes the frame-data computation aware (FDCA) technique, which is …
A Dsp-Based Active Disturbance Rejection Control Design For A 1-Kw H-Bridge Dc-Dc Power Converter, Bosheng Sun, Zhiqiang Gao
A Dsp-Based Active Disturbance Rejection Control Design For A 1-Kw H-Bridge Dc-Dc Power Converter, Bosheng Sun, Zhiqiang Gao
Electrical and Computer Engineering Faculty Publications
This paper presents the design and implementation of an advanced digital controller for a 1-kW H-bridge dc-dc power converter. A new control algorithm based on the active disturbance rejection concept is developed to cope with the highly nonlinear dynamics of the converter and the disturbances. An experimental digital control system is used to implement the new control strategy. It consists of a digital control board based on the TMS320C6711 digital signal processor chip, an analogy I/O board, and a complex programmable logic device pulsewidth-modulation generation board. Using a newly developed bandwidth-parametrization technique, an autotuning method based on noise quantification is …
Partition-Based Interpolation For Color Filter Array Demosaicking And Super-Resolution Reconstruction, Min Shao, Kenneth E. Barner, Russell C. Hardie
Partition-Based Interpolation For Color Filter Array Demosaicking And Super-Resolution Reconstruction, Min Shao, Kenneth E. Barner, Russell C. Hardie
Electrical and Computer Engineering Faculty Publications
A class of partition-based interpolators that addresses a variety of image interpolation applications are proposed. The proposed interpolators first partition an image into a finite set of partitions that capture local image structures. Missing high resolution pixels are then obtained through linear operations on neighboring pixels that exploit the captured image structure. By exploiting the local image structure, the proposed algorithm produces excellent performance on both edge and uniform regions. The presented results demonstrate that partition-based interpolation yields results superior to traditional and advanced algorithms in the applications of color filter array (CFA) demosaicking and super-resolution reconstruction.
On Optimization Of Sensor Selection For Aircraft Gas Turbine Engines, Ramgopal Mushini, Daniel J. Simon
On Optimization Of Sensor Selection For Aircraft Gas Turbine Engines, Ramgopal Mushini, Daniel J. Simon
Electrical and Computer Engineering Faculty Publications
Many science and management problems can be formulated as global optimization problems. Conventional optimization methods that make use of derivatives and gradients are not, in general, able to locate or identify the global optimum. Sometimes these problems can be solved using exact methods like brute force. Unfortunately, these methods become computationally intractable because of multidimensional search spaces. Hence, the application of heuristics for a class of problems that incorporates knowledge about the problem helps solve optimization problems. Optimization of sensor selection using heuristics can lead to significant improvements in the controllability and observability of a dynamic system. The aim of …
Scene-Based Nonuniformity Correction Technique For Focal-Plane Arrays Using Readout Architecture, Balaji Narayanan, Russell C. Hardie, Robert A. Muse
Scene-Based Nonuniformity Correction Technique For Focal-Plane Arrays Using Readout Architecture, Balaji Narayanan, Russell C. Hardie, Robert A. Muse
Electrical and Computer Engineering Faculty Publications
Spatial fixed pattern noise is a common and major problem in modern infrared imagers due to the nonuniform response of the photodiodes in the focal plane array of the imaging system. In addition, the nonuniform response of the readout and the digitization electronics, involved in multiplexing the signals from the photodiodes, causes further nonuniformity. In this paper, we describe a novel scene based nonuniformity correction algorithm that treats the aggregate nonuniformity in separate stages. Firstly, the nonuniformity from the readout amplifiers is corrected using knowledge of the readout architecture of the imaging system. In the second stage, the nonuniformity resulting …
A Wavelet-Based Multiresolution Pid Controller, Shahid Parvez, Zhiqiang Gao
A Wavelet-Based Multiresolution Pid Controller, Shahid Parvez, Zhiqiang Gao
Electrical and Computer Engineering Faculty Publications
A novel controller based on multiresolution decomposition using wavelets is presented. The controller is similar to a proportional-integral-derivative (PID) controller in principle and application. The output from a motion control system represents the cumulative effect of uncertainties such as measurement noise, frictional variation, and external torque disturbances, which manifest at different scales. The wavelet is used to decompose the error signal into signals at different scales. These signals are then used to compensate for the uncertainties in the plant. This approach provides greater expanse over the degree of control applied to the system. Through hardware and simulation results on motion …
Study Of Behavior Of Digital Modulations For Beam Steerable Reflectarray Antennas, Fuqin Xiong, Robert R. Romanofsky
Study Of Behavior Of Digital Modulations For Beam Steerable Reflectarray Antennas, Fuqin Xiong, Robert R. Romanofsky
Electrical and Computer Engineering Faculty Publications
This paper investigates the bit error rate (BER) performance of digital modulations in a system with a scanning reflectarray antenna. A reflectarray causes intersymbol interference (ISI) in a digitally modulated signal, its phase shifters' phase errors cause signal distortion, and its phase shifters' phase transient causes beam pattern degradation during direction switching. In this paper, composite signal models of the reflectarray are established for both static and transient states. Due to different feed-to-element distances and the element-to-observation distances, different delays exist in signal components. These delays cause ISI whose effect is analyzed and evaluated. Effects of phase shifters' phase errors …
Signal Flow Analysis, Partha P. Banerjee
Signal Flow Analysis, Partha P. Banerjee
Electrical and Computer Engineering Faculty Publications
Signal flow graphs are a viable alternative to block diagrammatic representation of a system. What makes signal flow graphs attractive is that certain features from graph theory can be applied to the simplification and the synthesis of complex systems.
Design Of A Satellite Cluster System In Distributed Simulation, Jong Sik Lee, Thong Luu, Vijaya K. Konangi
Design Of A Satellite Cluster System In Distributed Simulation, Jong Sik Lee, Thong Luu, Vijaya K. Konangi
Electrical and Computer Engineering Faculty Publications
This article presents the design and development of a satellite cluster system that supports an interfederation communication in High Level Architecture (HLA)-compliant distributed simulation. The interfederation communication enables the execution of a complex, large-scale cluster system of distributed satellites that share the dispersed data assets among satellite components collaboratively. After a brief review of the HLA bridge for interfederation communication, the authors discuss the design issues related to a satellite cluster system that provides cluster management, interfederation communication, and communication data management. They analyze system performance and scalability for centralized and decentralized configurations. The empirical results on the heterogeneous …
Unification Of Transactions And Replication In Three-Tier Architectures Based On Corba, Wenbing Zhao, Louise E. Moser, P. Michael Melliar-Smith
Unification Of Transactions And Replication In Three-Tier Architectures Based On Corba, Wenbing Zhao, Louise E. Moser, P. Michael Melliar-Smith
Electrical and Computer Engineering Faculty Publications
In this paper, we describe a software infrastructure that unifies transactions and replication in three-tier architectures and provides data consistency and high availability for enterprise applications. The infrastructure uses transactions based on the CORBA object transaction service to protect the application data in databases on stable storage, using a roll-backward recovery strategy, and replication based on the fault tolerant CORBA standard to protect the middle-tier servers, using a roll-forward recovery strategy. The infrastructure replicates the middle-tier servers to protect the application business logic processing. In addition, it replicates the transaction coordinator, which renders the two-phase commit protocol nonblocking and, thus, …
Power Analysis And Optimization Techniques For Energy Efficient Computer Systems, Wissam Chedid, Chansu Yu, Ben Lee
Power Analysis And Optimization Techniques For Energy Efficient Computer Systems, Wissam Chedid, Chansu Yu, Ben Lee
Electrical and Computer Engineering Faculty Publications
Reducing power consumption has become a major challenge in the design and operation of to-day’s computer systems. This chapter describes different techniques addressing this challenge at different levels of system hardware, such as CPU, memory, and internal interconnection network, as well as at different levels of software components, such as compiler, operating system and user applications. These techniques can be broadly categorized into two types: Design time power analysis versus run-time dynamic power management. Mechanisms in the first category use ana-lytical energy models that are integrated into existing simulators to measure the system’s power consumption and thus help engineers to …
Functional Nanoparticles In Thin Films As Sensing Media, Elena A. Guliants, Ryan Schwarb, Hope Bearbower, James R. Gord, Christopher E. Bunker
Functional Nanoparticles In Thin Films As Sensing Media, Elena A. Guliants, Ryan Schwarb, Hope Bearbower, James R. Gord, Christopher E. Bunker
Electrical and Computer Engineering Faculty Publications
The combination of unique properties offered by materials on the nanoscale with the increased role of surface chemistry in nanostructured solids makes core-shell nanoparticles extremely attractive for application to "smart" thin-film coatings. Sensing properties of nanoparticle-based thin films were studied in several systems containing organic-coated semiconductor and metallic particles. In semiconductors, the interaction of organic shell and/or thin-film "matrix" with the environment results in changes in the nanoparticle's surface states, altering the optical properties of the thin film. Measuring the electrical properties of thin films composed of metallic cores with hydrocarbon shells offers another mechanism to monitor the local environment …