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Articles 241 - 270 of 370

Full-Text Articles in Electrical and Computer Engineering

Consistency Restoration In Point And Interval Spatio-Temporal Reasoning, Florent Launay, Debasis Mitra Apr 2004

Consistency Restoration In Point And Interval Spatio-Temporal Reasoning, Florent Launay, Debasis Mitra

Electrical Engineering and Computer Science Faculty Publications

In this work, we first have proposed a technique to define the “causes” of inconsistency on an online point based reasoning constraint network. Second, we introduce an algorithm that proposes the user a minimal set of relations to remove when inconsistencies are detected. We have developed and implemented a battery of algorithms for the purpose of this type of reasoning. Some useful theorems and properties are defined for proving the ‘minimal’ aspect of the algorithm. Finally, we found that our investigation was a polynomially solvable sub problem of the vertex cover problem.

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Semi-Automatic Road Extraction From Aerial Images, Somkait Udomhunsakul, Samuel Peter Kozaitis, Uthai Thai Sritheeravirojana Feb 2004

Semi-Automatic Road Extraction From Aerial Images, Somkait Udomhunsakul, Samuel Peter Kozaitis, Uthai Thai Sritheeravirojana

Electrical Engineering and Computer Science Faculty Publications

In this work, we proposed a method to detect roads in aerial imagery. In our approach, we applied the wavelet transform in a multiresolution sense by forming the products of wavelet coefficients at the different scales to locate and identify roads. After detecting possible road pixels, we used a graph searching algorithm to identify roads. We found that our approach leads to an effective method to form the basis of a road extraction approach.

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On The Implementation Of Swarmlinda? A Linda System Based On Swarm Intelligence (Extended Version), Ahmed Charles, Ronaldo Menezes, Robert Tolksdorf Feb 2004

On The Implementation Of Swarmlinda? A Linda System Based On Swarm Intelligence (Extended Version), Ahmed Charles, Ronaldo Menezes, Robert Tolksdorf

Electrical Engineering and Computer Science Faculty Publications

Natural-forming multi-agent systems (aka Swarms) can grow to enormous sizes and perform seemingly complex tasks without the existence of any centralized control. Their success comes from the fact that agents are simple and the interaction with the environment and neighboring agents is local in nature. In this paper we discuss the implementation of SwarmLinda, a Linda-based system that abstracts Linda concepts in terms of swarm intelligence constructs such as scents and stigmergy. The goal of this implementation is to achieve many characteristics such as scalability, adaptiveness and some level of fault tolerance. This paper describes our initial version of SwarmLinda …

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A Faster Technique For Distributed Constraint Satisfaction And Optimization With Privacy Enforcement, Marius C. Silaghi Jan 2004

A Faster Technique For Distributed Constraint Satisfaction And Optimization With Privacy Enforcement, Marius C. Silaghi

Electrical Engineering and Computer Science Faculty Publications

A problem that received recent attention is the development of negotiation/cooperation techniques for solving naturally distributed problems with privacy requirements. An important amount of research focused on those problems that can be modeled with distributed constraint satisfaction, where the constraints are the secrets of the participants. Distributed AI develops techniques where the agents solve such problems without involving trusted servers. Some of the existing techniques aim for various tradeoffs between complexity and privacy guarantees [MTSY03], some aim only at high efficiency [ZM04], while others aim to offer maximal privacy [Sil03]. While the last mentioned work achieves an important level of …

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Effective Quality Analysis For Video Streaming Over Wireless Ad Hoc Network, Zhihai He, Chang Wen Chen Jan 2004

Effective Quality Analysis For Video Streaming Over Wireless Ad Hoc Network, Zhihai He, Chang Wen Chen

Electrical Engineering and Computer Science Faculty Publications

Video encoding and streaming over wireless ad hoc network operates under severe conditions, such as time-varying channel characteristics with bursty errors, limit power for data transmission, and dynamic topology of the self-organized network, stringent time delay for packet delivery, etc. Due to the dynamic topology, complex mechanism, and time-varying nature of the wireless ad hoc network, the network system and the streaming service often exhibit unpredictable behaviors. The ultimate goal in the wireless video streaming service is to provide the end user with the best possible video presentation quality. The video streaming quality, often measured by the end-to-end picture distortion, …

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Collaborative Image Transmission Over Wireless Sensor Networks, Min Wu, Chang Wen Chen Jan 2004

Collaborative Image Transmission Over Wireless Sensor Networks, Min Wu, Chang Wen Chen

Electrical Engineering and Computer Science Faculty Publications

The imaging sensors are able to provide intuitive visual information for quick recognition and decision. However, imaging sensors usually generate vast amount of data. Thus, processing of image data collected in the sensor network for the purpose of energy efficient transmission poses a significant technical challenge. In particular, when a cluster of imaging sensors is activated to track certain moving target, multiple sensors may be collecting similar visual information simultaneously. With correlated image data, we need to intelligently reduce the redundancy among the neighboring sensors so as to minimize the energy for transmission, the primary source of sensor energy consumption. …

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Layered Unequal Loss Protection For Progressive Image Transmission Over Packet Loss Channels, Jianfei Cai, Xiangjun Li, Chang Wen Chen Jan 2004

Layered Unequal Loss Protection For Progressive Image Transmission Over Packet Loss Channels, Jianfei Cai, Xiangjun Li, Chang Wen Chen

Electrical Engineering and Computer Science Faculty Publications

In the past, many schemes have been proposed for progressive image transmission using unequal error protection (UEP) or unequal loss protection (ULP). However, most existing UEP/ULP schemes do not consider the minimum image quality requirement and usually have high computation complexity. In this paper, we propose a layered ULP (L-ULP) scheme for progressive image transmission over packet loss channels, which is able to solve the mentioned problems of existing ULP schemes by smartly choosing the layers. The numerical results show that the proposed L-ULP scheme is quite promising for fast image transmission over packet loss networks.

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A Half D1 Mpeg-4 Encoder On The Bsp-15 Dsp, Lulin Chen, Zhihai He, Chang Wen Chen, Michael A. Isnardi Jan 2004

A Half D1 Mpeg-4 Encoder On The Bsp-15 Dsp, Lulin Chen, Zhihai He, Chang Wen Chen, Michael A. Isnardi

Electrical Engineering and Computer Science Faculty Publications

In this paper, we present the work on implementation of a half-Dl interlaced MPEG-4 encoder with Equator Technology DSP chip, BSP-15. The BSP-15 DSP consists mainly of a VLIW core, Co-processors, and media I/O interfaces. The encoder utilizes several BSP-15 functional blocks in parallel. In general, the VLIW performs pixel processing that is computationally intensive. The VLx coprocessor completes variable length coding. Further parallelism is obtained by pre-loading data cache and doubling data buffers. Given the DSP processing power and real time requirements, a complexity control scheme is implemented. A frame-level quantization scheme with quality and rate control is employed. …

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Ubiquitous Map-Image Access Through Wireless Overlay Networks, Jianfei Cai, Haijie Huang, Zefeng Ni, Chang Wen Chen Jan 2004

Ubiquitous Map-Image Access Through Wireless Overlay Networks, Jianfei Cai, Haijie Huang, Zefeng Ni, Chang Wen Chen

Electrical Engineering and Computer Science Faculty Publications

With the availability of various wireless link-layer technologies, such as Bluetooth, WLAN and GPRS, in one wireless device, ubiquitous communications can be realized through managing vertical handoff in the environment of wireless overlay networks. In this paper, we propose a vertical handoff management system based on mobile IPv6, which can automatically manage the multiple network interfaces on the mobile device, and make decisions on network interface selection according to the current situation. Moreover, we apply our proposed vertical handoff management with JPEG-2000 codec to the wireless application of map image access. The developed system is able to provide seamless communications, …

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Speckle Denoising Using Wavelet Transforms And Higher-Order Statistics, Samuel Peter Kozaitis, Anurat Ingun Jan 2004

Speckle Denoising Using Wavelet Transforms And Higher-Order Statistics, Samuel Peter Kozaitis, Anurat Ingun

Electrical Engineering and Computer Science Faculty Publications

We reduced speckle noise in SAR imagery by retaining only those wavelet coefficients with significant third-order correlation coefficients. These coefficients were generated from the cross-correlation functions of the image and wavelet basis functions. Using this approach, we compared the results between directly applying our denoising method, and first preprocessing by taking the logarithm of an image. In our approach, we examined wavelet coefficients in an environment where the contribution from the second-order moment of the noise had been reduced.

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Extended Hough Methodology For 3d Feature Detection, Rufus H. Cofer, Samuel Peter Kozaitis, Jihun Cha Nov 2003

Extended Hough Methodology For 3d Feature Detection, Rufus H. Cofer, Samuel Peter Kozaitis, Jihun Cha

Electrical Engineering and Computer Science Faculty Publications

In an effort to make automatically detect image features for pattern recognition, we described a 3-dimensional (3-D) Hough transform. We describe two interlocking theoretical extensions to greatly enhance the Hough transform's ability to handle finite lineal features and allow directed search for various features while balancing memory and computational complexity. We computed the 2-D Hough transform of 1-D slices of an image which results in a 2-D to 3-D transform. Features such as line segments will cluster in a particular location so that both line orientation and spatial extent can be determined. This approach allows the Hough transform to be …

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Hgcdte Focal Plane Array Cost Modeling, Thomas J. Sanders, Glenn T. Hess Oct 2003

Hgcdte Focal Plane Array Cost Modeling, Thomas J. Sanders, Glenn T. Hess

Electrical Engineering and Computer Science Faculty Publications

Focal plane arrays (FPAs) are used in many applications for detecting infrared (IR) radiation where normal sight with light in the visible spectrum is not possible. To effectively detect this IR radiation, complex semiconductor diodes, cooled to low temperatures, are usually used. The most common of these semiconductor materials is the II-VI alloy semiconductor system using HgCdTe, which is often called MCT. Focal plane arrays with over 1000 pixels have been fabricated. The cost of these very complex systems is becoming a very important consideration in decisions of where to use these FPAs. The focal plane array actually consists of …

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Line Detection Using Wavelet Filters, Somkait Udomhunsakul, Samuel Peter Kozaitis, Uthai Thai Sritheeravirojana, A. Khempila Sep 2003

Line Detection Using Wavelet Filters, Somkait Udomhunsakul, Samuel Peter Kozaitis, Uthai Thai Sritheeravirojana, A. Khempila

Electrical Engineering and Computer Science Faculty Publications

We proposed a new line detection method in noisy images using Mexican hat wavelet filters. In our approach, we applied the wavelet transform in a multiresolution sense by forming the products of wavelet coefficients at the different scales to locate and identify lines at different scales. In addition, we also considered shifting line locations through multiple scales for robust line detection in the presence of noise. We found that our approach leads to an effective method to form the basis of a line detection approach.

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Reduction Of Multiplicative Noise Using Higher-Order Statistics, Samuel Peter Kozaitis, Anurat Ingun, Rufus H. Cofer Sep 2003

Reduction Of Multiplicative Noise Using Higher-Order Statistics, Samuel Peter Kozaitis, Anurat Ingun, Rufus H. Cofer

Electrical Engineering and Computer Science Faculty Publications

We used a higher-order correlation-based method for signal denoising of images corrupted by multiplicative noise. Using the logarithm of an image, we applied a third-order correlation technique for identification of wavelet coefficients that contained mostly signal. In our approach, we examined wavelet coefficients in an environment where the contribution from the second-order moment of the noise had been reduced. Our results compared favorably and were less sensitive to threshold selection when compared to a second-order wavelet denoising method.

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Extended Hough Methodology In Geo-Spatial Image Exploitation, Rufus H. Cofer, Samuel Peter Kozaitis, Jihun Cha Aug 2003

Extended Hough Methodology In Geo-Spatial Image Exploitation, Rufus H. Cofer, Samuel Peter Kozaitis, Jihun Cha

Electrical Engineering and Computer Science Faculty Publications

Hough transform theory provides a heuristically appealing approach toward finding lineal features in imagery. Unfortunately direct algorithmic implementation of its theory results in many practical problems. We provide two interlocking theoretical extensions to greatly enhances the Hough transform's ability to handle finite lineal features and allow directed search for parallel lines within the scene while balancing memory and computational complexity. Both extensions involve expansion of the Hough space concept to allow easier access to processed data for both dedicated silicon and general-purpose computer implementations.

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Linear Feature Detection Of Rural Imagery Using Multiresolution Filters, Samuel Peter Kozaitis, Rufus H. Cofer Aug 2003

Linear Feature Detection Of Rural Imagery Using Multiresolution Filters, Samuel Peter Kozaitis, Rufus H. Cofer

Electrical Engineering and Computer Science Faculty Publications

We detected roads in aerial imagery using a method based on lineal feature detection. Our method used the products of wavelet coefficients at several scales were to identify and locate lineal features. Using our approach effectively increased the size of the region we examined when looking for possible road pixels, and decreased the probability of false positive road pixels. Then, we used a shortest path algorithm to link road pixels to form road networks. Our approach restricted possible road network solutions based on the initial detection of road pixels. We found that our approach leads to an effective method for …

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Imagery Chain Assessment For Feature Extraction, Rufus H. Cofer, Samuel Peter Kozaitis Aug 2003

Imagery Chain Assessment For Feature Extraction, Rufus H. Cofer, Samuel Peter Kozaitis

Electrical Engineering and Computer Science Faculty Publications

It is shown that the image chain has important effects upon the quality of feature extraction. Exact analytic ROC results are given for the case where arbitrary multivariate normal imagery is passed to a Bayesian feature detector designed for multivariate normal imagery with a diagonal covariance matrix. Plots are provided to allow direct visual inspection of many of the more readily apparent effects. Also shown is an analytic tradeoff that says doubling background contrast is equal to halving sensor to scene distance or sensor noise. It is also shown that the results provide a lower bound to the ROC of …

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Wavelet-Based Image Compression Using Perceptual Distortion Metric, Hemen Goswami, Samuel Peter Kozaitis Aug 2003

Wavelet-Based Image Compression Using Perceptual Distortion Metric, Hemen Goswami, Samuel Peter Kozaitis

Electrical Engineering and Computer Science Faculty Publications

Bits are allocated to various subbands to minimize a particular cost function to achieve compression in subband coding. The most common cost function is the L2 norm based on mean squared error (MSE). However, the MSE often fails to correspond to the perceptual quality of the image, especially at low bit rate. In this paper, we allocate bits into various subbands by minimizing the Minkowsky metric - a commonly used perceptual distortion measure. We then design the quantizer for each subband independent of each other based on the allocated bits. Experimental results indicate improved perceptual quality for the compressed images …

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An Artificial Immune System For Securing Mobile Ad Hoc Networks Against Intrusion Attacks, William S. Hortos Aug 2003

An Artificial Immune System For Securing Mobile Ad Hoc Networks Against Intrusion Attacks, William S. Hortos

Electrical Engineering and Computer Science Faculty Publications

An artificial immune system (AIS) for securing mobile ad hoc networks (MANET) against intrusion attacks was presented. A state vector of features and metrics based on the published Secure Routing Protocol (SRP) for MANETs was constructed to encode network security characteristics. The results were reported along with a performance analysis comparing the AIS approach with competing techniques.

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Cross-Layer Protocols Optimized For Real-Time Multimedia Services In Energy-Constrained Mobile Ad Hoc Networks, William S. Hortos Jul 2003

Cross-Layer Protocols Optimized For Real-Time Multimedia Services In Energy-Constrained Mobile Ad Hoc Networks, William S. Hortos

Electrical Engineering and Computer Science Faculty Publications

The optimization of cross-layer protocols for real-time multimedia services in energy-constrained mobile ad hoc networks (MANET) was presented. The cross-layer optimization was based on stochastic dynamic programming conditions derived from time-dependent models of MANET packet flows. The performance of the optimized cross-layer protocols was also determined by using dynamic programming conditions.

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Boundary Detection In Tokenizing Network Application Payload For Anomaly Detection, Rachna Vargiya, Philip K. Chan Jun 2003

Boundary Detection In Tokenizing Network Application Payload For Anomaly Detection, Rachna Vargiya, Philip K. Chan

Electrical Engineering and Computer Science Faculty Publications

Most of the current anomaly detection methods for network traffic rely on the packet header for studying network traffic behavior. We believe that significant information lies in the payload of the packet and hence it is important to model the payload as well. Since many protocols exist and new protocols are frequently introduced, parsing the payload based on the protocol specification is time-consuming. Instead of relying on the specification, we propose four different characteristics of streams of bytes, which can help us develop algorithms for parsing the payload into tokens. We feed the extracted tokens from the payload to anomaly …

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Determining The Number Of Clusters/Segments In Hierarchical Clustering/Segmentation Algorithms, Stan Salvador, Philip K. Chan Jun 2003

Determining The Number Of Clusters/Segments In Hierarchical Clustering/Segmentation Algorithms, Stan Salvador, Philip K. Chan

Electrical Engineering and Computer Science Faculty Publications

We investigate techniques to automatically determine the number of clusters to return from hierarchical clustering and segmentation algorithms. We propose an efficient algorithm, the L Method, that finds the "knee" in a '# of clusters vs. clustering evaluation metric' graph. Using the knee is well-known but is not a particularly well-understood method to determine the number of clusters. We explore the feasibility of this method, and attempt to determine in which situations it will and will not work.

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Improving Learning Implicit User Interest Hierarchy With Variable Length Phrases, Hyoung-Rae Kim, Philip K. Chan Jun 2003

Improving Learning Implicit User Interest Hierarchy With Variable Length Phrases, Hyoung-Rae Kim, Philip K. Chan

Electrical Engineering and Computer Science Faculty Publications

A continuum of general to specific interests of a user called a user interest hierarchy (UIH) represents a user's interests at different abstraction levels. A UIH can be learned from a set of web pages visited by a user. In this paper, we focus on improving learning the UIH by adding phrases. We propose the VPF algorithm that can find variable length phrases without any user-defined parameter. To identify meaningful phrases, we examine various correlation functions with respect to well-known properties and other properties that we propose.

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Learning Rules From System Call Arguments And Sequences For Anomaly Detection, Guarav Tandon, Philip K. Chan Jun 2003

Learning Rules From System Call Arguments And Sequences For Anomaly Detection, Guarav Tandon, Philip K. Chan

Electrical Engineering and Computer Science Faculty Publications

Many approaches have been suggested and various systems have been modeled to detect intrusions from anomalous behavior of systems calls as a result of an attack. Though these techniques have been shown to be quite effective, a key element seems to be missing -- the inclusion and utilization of the system call arguments to create a richer, more valuable signature and to use this information to model the intrusion detection system more accurately. We put forth the idea of adopting a rule learning approach that mobilizes rules based upon system calls and models the system for normal traffic using system …

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Identifying Outliers Via Clustering For Anomaly Detection, Muhammad H. Arshad, Philip K. Chan Jun 2003

Identifying Outliers Via Clustering For Anomaly Detection, Muhammad H. Arshad, Philip K. Chan

Electrical Engineering and Computer Science Faculty Publications

Detecting known vulnerabilities (Signature Detection) is not sufficient for complete security. This has raised recent interest in Anomaly Detection (AD), in which a model is built from normal behavior and significant deviations from this model are flagged anomalous. However, most AD algorithm assume clean training data, which could be hard to obtain. Our proposed algorithm relaxes. For this, we define the notion a strong outlier, which is suspicious at both local and global levels. Finally we illustrate the effectiveness of our approach on the DARPA '99 dataset and find that our approach is at par in number of detections at …

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A Local Search Optimization Algorithm Based On Natural Principles Of Gravitation, Barry Webster, Philip J. Bernhard Apr 2003

A Local Search Optimization Algorithm Based On Natural Principles Of Gravitation, Barry Webster, Philip J. Bernhard

Electrical Engineering and Computer Science Faculty Publications

This paper discusses the concept of an algorithm designed to locate the optimal solution to a problem in a (presumably) very large solution space. The algorithm attempts to locate the optimal solution to the problem by beginning a search at an arbitrary point in the solution space and then searching in the "local" area around the start point to find better solutions. The algorithm completes either when it locates what it thinks is the optimal solution or when predefined halt conditions have been met. The algorithm is repair-based, that is, it begins with a given solution and attempts to "repair" …

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Denoising Using Higher-Order Statistics, Samuel Peter Kozaitis, Sunghee Kim Apr 2003

Denoising Using Higher-Order Statistics, Samuel Peter Kozaitis, Sunghee Kim

Electrical Engineering and Computer Science Faculty Publications

We used a higher-order correlation-based method for signal denoising. In our approach, we determined which wavelet coefficients contained mostly noise, or signal, based on higher-order statistics. Because the higher that second-order moments of the Gaussian probability function are zero, the third-order correlation coefficient will not have a statistical contribution from Gaussian noise. We obtained results for both 1-D signals and images. In all cases, our approach showed improved results when compared to a more popular denoising method.

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A Representation Scheme For Finite Length Strings, Guarav Tandon, Debasis Mitra Apr 2003

A Representation Scheme For Finite Length Strings, Guarav Tandon, Debasis Mitra

Electrical Engineering and Computer Science Faculty Publications

This study is an attempt to create a canonical representation scheme for finite length strings to simplify the study of the theory behind different classes of patterns and to ease the understanding of the underlying separability issues. This could then be used to determine what kinds of techniques are suitable for what class of separability (linear, multi-linear, or non-linear). This representation can then be used in intrusion detection, biological sequences, pattern recognition/classification and numerous other applications.

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A Machine Learning Approach To Anomaly Detection, Philip K. Chan, Matthew V. Mahoney, Muhammad H. Arshad Mar 2003

A Machine Learning Approach To Anomaly Detection, Philip K. Chan, Matthew V. Mahoney, Muhammad H. Arshad

Electrical Engineering and Computer Science Faculty Publications

Much of the intrusion detection research focuses on signature (misuse) detection, where models are built to recognize known attacks. However, signature detection, by its nature, cannot detect novel attacks. Anomaly detection focuses on modeling the normal behavior and identifying significant deviations, which could be novel attacks. In this paper we explore two machine learning methods that can construct anomaly detection models from past behavior. The first method is a rule learning algorithm that characterizes normal behavior in the absence of labeled attack data. The second method uses a clustering algorithm to identify outliers.

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Learning States And Rules For Time Series Anomaly Detection, Stan Salvador, Philip K. Chan, John Brodie Mar 2003

Learning States And Rules For Time Series Anomaly Detection, Stan Salvador, Philip K. Chan, John Brodie

Electrical Engineering and Computer Science Faculty Publications

In this paper, we investigate machine learning techniques for discovering knowledge that can be used to monitor the operation of devices or systems. Specifically, we study methods for generating models that can detect anomalies in time series data. The normal operation of a device can usually be characterized in different temporal states. To identify these states, we introduce a clustering algorithm called Gecko that can automatically determine a reasonable number of clusters using our proposed "L" method. We then use the RIPPER classification algorithm to describe these states in logical rules. Finally, transitional logic between the states is added to …

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