Computer Engineering Commons^™

Dynamic Interactions For Network Visualization And Simulation, Cigdem Yetisti

Theses and Dissertations

Most network visualization suites do not interact with a simulator, as it executes. Nor do they provide an effective user interface that includes multiple visualization functions. The subject of this research is to improve the network visualization presented in the previous research [5] adding these capabilities to the framework. The previous network visualization did not have the capability of altering specific visualization characteristics, especially when detailed observations needed to be made for a small part of a large network. Searching for a network event in this topology might cause large delays leading to lower quality user interface. In addition to …

Stochastic Estimation And Control Of Queues Within A Computer Network, Mingook Kim

Theses and Dissertations

Captain Nathan C. Stuckey implemented the idea of the stochastic estimation and control for network in OPNET simulator. He used extended Kalman filter to estimate packet size and packet arrival rate of network queue to regulate queue size. To validate stochastic theory, network estimator and controller is designed by OPNET model. These models validated the transient queue behavior in OPNET and work of Kalman filter by predicting the queue size and arrival rate. However, it was not enough to verify a theory by experiment. So, it needed to validate the stochastic control theory with other tools to get high validity. …

Optimized Robust Adaptive Networks In Supervisory Control And Data Acquisition Systems, Luis A. Oquendo Class

Theses and Dissertations

This thesis investigates the application of a Exponential Weighted Moving Average (EWMA) to be used as a memory buffer in conjunction with Special Protection Schemes (SPS) using the Electric Power and Communication Synchronizing Simulator (EPOCHS). It is proposed that using an SPS incorporating EWMA can compensate for the network layer lack of guarantee of packet delivery and provide for the stability and integrity of the power grid under a catastrophic event. The performance of the proposed SPS is evaluated using a discrete event computer simulation developed using the NS2 network simulator and the Power System Simulator for Engineering (PSS/E) power …

A Neutral Network Based Vehicle Classification System For Pervasive Smart Road Security, Naixue Xiong, Jing (Selena) He, Jong Hyuk Park, Donald Cooley

Faculty Articles

Pervasive smart computing environments make people get accustomed to convenient and secure services. The overall goal of this research is to classify vehicles along the I215 freeway in Salt Lake City, USA. This information will be used to predict future roadway needs and the expected life of a roadway. The classification of vehicles will be performed by a synthesis of multiple sets of features. All feature sets have not yet been determined; however, one such set will be the reduced wavelet transform of the image of a vehicle. In order to use such a feature, it is necessary that the …

Sharing And Fusing Landmark Information In A Team Of Autonomous Robots, Damian M. Lyons

Faculty Publications

A team of robots working to explore and map a space may need to share information about landmarks so as register local maps and to plan effective exploration strategies. In this paper we investigate the use of spatial histograms (spatiograms) as a common representation for exchanging landmark information between robots. Each robot can use sonar, stereo, laser and image information to identify potential landmarks. The sonar, laser and stereo information provide the spatial dimension of the spatiogram in a landmark-centered coordinate frame while video provides the image information. We call the result a terrain spatiogram. This representation can be shared …

Empirical Formulas For Economic Fluctuations: Towards A New Justification, Tanja Magoc, Vladik Kreinovich

Departmental Technical Reports (CS)

To avoid crisis developments, it is important to make financial decisions based on the models which correct predict the probabilities of large-scale economic fluctuations. At present, however, most financial decisions are based on Gaussian random-walk models, models which are known to underestimate the probability of such fluctuations. There exist better empirical models for describing these probabilities, but economists are reluctant to use them since these empirical models lack convincing theoretical explanations. To enhance financial stability and avoid crisis situations, it is therefore important to provide theoretical justification for these (more) accurate empirical models. Such a justification is provided in this …

Guesstimation: A New Justification Of The Geometric Mean Heuristic, Olga Kosheleva, Vladik Kreinovich

Departmental Technical Reports (CS)

In many practical situations in which the only information we have about the quantity x is that its value is within an interval [x,X], a reasonable estimate for this quantity is the geometric mean of the bounds, i.e., the square root of the product x*X. In this paper, we provide a new justification for this geometric mean heuristic.

Stochastic Volatility Models And Financial Risk Measures: Towards New Justifications, Hung T. Nguyen, Vladik Kreinovich, Songsak Sriboonchitta

Departmental Technical Reports (CS)

We provide theoretical justifications for the empirical successes of (1) the asymmetric heteroskedasticity models of stochastic volatility in mathematical finance and (2) Wang's distorted probability risk measures in actuarial and investment sciences, using a unified framework of symmetry groups.

Mobility Handling In Mac For Wireless Ad Hoc Networks, Anjali Raja, Xiao Su

Faculty Publications

Wireless Sensor Networks (WSNs) are becoming popular in a wide variety of applications. In a WSN, sensor nodes can be static or mobile, depending on applications. Handling mobility in a sensor network can pose interesting challenges in sensor protocol design, and special algorithms are needed to adapt to mobility in the network. In this paper, we survey the current state of art in handling mobility in sensor networks. We first study how mobility affects the design of different layers in the sensor network architecture, and then take a closer look at mobility handling in the MAC layer. We also describe …

Propitious Checkpoint Intervals To Improve System Performance, Sarala Arunagiri, John T. Daly, Patricia J. Teller

Departmental Technical Reports (CS)

The large scale of current and next-generation massively parallel processing (MPP) systems presents significant challenges related to fault tolerance. For applications that perform periodic checkpointing, the choice of the checkpoint interval, the period between checkpoints, can have a significant impact on the execution time of the application and the number of checkpoint I/O operations performed by the application. These two metrics determine the frequency of checkpoint I/O operations performed by the application, and thereby, the contribution of the checkpoint operations to the I/O bandwidth demand made by the application. In a computing environment where there are concurrent applications competing for …

Experiments In Teaching An Engaging And Demystifying Introduction To Algorithms: Installment 1: Huffman Codes, Alan Siegel, Eric Freudenthal

Departmental Technical Reports (CS)

As is well known -- the Huffman algorithm is a remarkably simple, and is a wonderfully illustrative example of the greedy method in algorithm design. However, the Huffman problem, which is to design an optimal binary character code (or an optimal binary tree with weighted leaves) is intrinsically technical, and its specification is ill-suited for students with modest mathematical sophistication.

This difficulty is circumvented by introducing an alternative 'precursor' problem that is easy to understand, and where this understanding can lead to student-devised solutions: how to merge k sorted lists of varying length together as efficiently as possible. Once students …

Fast Convolution And Fast Fourier Transform Under Interval Uncertainty, Guoqing Liu, Vladik Kreinovich

Departmental Technical Reports (CS)

Convolution y(t), defined as an integral of a(t-s)*x(s) ds, is one of the main techniques in digital signal processing. A straightforward computation of the convolution y(t) requires O(n^2) steps, where n is the number of observations x(t0),...,x(t(n-1)). It is well known that by using the Fast Fourier Transform (FFT) algorithm, we can compute convolution much faster, with computation time O(n*log(n)).

In practice, we only know the signal x(t) and the function a(t) with uncertainty; sometimes, we know them with interval uncertainty, i.e., we know intervals [x-(t),x+(t)] and [a-(t),a+(t)] that contain the actual (unknown) functions x(t) and a(t). In such situations, …

Vivisimo Customer Case Study, Vivisimo

Library Press and Events

Capitalizing on the power of the Internet, the Houston Academy of Medicine-Texas Medical Center (HAM-TMC) Library is using search to reinvent itself in this digital age. By using the Vivisimo Velocity Search Platform to search its multiple repositories, the library has helped users find information they never knew existed as well as positioned the library as a thought leader in its community.

Enhancing The Ns-2 Network Simulator For Near Real-Time Control Feedback And Distributed Simulation Breaks, John S. Weir

Theses and Dissertations

A network simulator coupled with a visualization package enables the human visual system to analyze the results of network modeling as a supplement to analytical data analysis. This research takes the next step in network simulator and visualization suite interaction. A mediator (or run-time infrastructure (RTI) in the literature) provides researchers the potential to interact with a simulation as it executes. Utilizing TCP/IP sockets, the mediator has the capability to connect multiple visualization packages to a single simulation. This new tool allows researchers to change simulation parameters on the y without restarting the network simulation.

The Evaluation Of Rekeying Protocols Within The Hubenko Architecture As Applied To Wireless Sensor Networks, Cory J. Antosh

Theses and Dissertations

This thesis investigates the impact of using three different rekeying protocols–pair-wise, hierarchical, and Secure Lock within a wireless sensor network (WSN) under the Hubenko architecture. Using a Matlab computer simulation, the impact of the three rekeying protocols on the number of bits transmitted across the network and the amount of battery power consumed in WSN nodes during rekey operations is investigated. Baseline pair-wise rekeying performance can be improved by using either Secure Lock or hierarchical rekeying. The best choice depends on the size of the WSN and the size of the key used. Hierarchical rekeying is the best choice for …

Opinion Mining With The Sentwordnet Lexical Resource, Bruno Ohana

Dissertations

Sentiment classification concerns the application of automatic methods for predicting the orientation of sentiment present on text documents. It is an important subject in opinion mining research, with applications on a number of areas including recommender and advertising systems, customer intelligence and information retrieval. SentiWordNet is a lexical resource of sentiment information for terms in the English language designed to assist in opinion mining tasks, where each term is associated with numerical scores for positive and negative sentiment information. A resource that makes term level sentiment information readily available could be of use in building more effective sentiment classification methods. …

Visual Word Proximity And Linguistics For Semantic Video Indexing And Near-Duplicate Retrieval, Yu-Gang Jiang, Chong-Wah Ngo

Research Collection School Of Computing and Information Systems

Bag-of-visual-words (BoW) has recently become a popular representation to describe video and image content. Most existing approaches, nevertheless, neglect inter-word relatedness and measure similarity by bin-to-bin comparison of visual words in histograms. In this paper, we explore the linguistic and ontological aspects of visual words for video analysis. Two approaches, soft-weighting and constraint-based earth mover’s distance (CEMD), are proposed to model different aspects of visual word linguistics and proximity. In soft-weighting, visual words are cleverly weighted such that the linguistic meaning of words is taken into account for bin-to-bin histogram comparison. In CEMD, a cross-bin matching algorithm is formulated such …

Chip To Chip Optical Interconnection Using Mems Mirrors, Tod V. Laurvick

Theses and Dissertations

This experiment explores the use of MEMS mirrors to direct subsurface optical signals to another device and reception of those signals for use in chip to chip communications. Devices were built in PolyMUMPs to control horizontal and vertical beam direction and tilting in the outgoing signal and MEMS beam splitters for the incoming signal. Several elements of the outgoing beam path were successful and those which needed improvement indicate a high probability of success with limited trials needed and currently successful design elements could still be improved within the scope of PolyMUMPs. The incoming beam path elements were not successful …

Automated Virtual Machine Introspection For Host-Based Intrusion Detection, Brett A. Pagel

Theses and Dissertations

This thesis examines techniques to automate configuration of an intrusion detection system utilizing hardware-assisted virtualization. These techniques are used to detect the version of a running guest operating system, automatically configure version-specific operating system information needed by the introspection library, and to locate and monitor important operating system data structures. This research simplifies introspection library configuration and is a step toward operating system independent introspection. An operating system detection algorithm and Windows virtual machine system service dispatch table monitor are implemented using the Xen hypervisor and a modified version of the XenAccess library. All detection and monitoring is implemented from …

Adaptive Control Of Woofer-Tweeter Adaptive Optics, Jimmie J. Perez

Theses and Dissertations

Adaptive optics applies advanced sensing and control to improve the ability of optical systems to collect images through a turbulent atmosphere. The results of this research effort demonstrate that the combination of two recent approaches improves the performance of adaptive optics in directed energy and laser communication scenarios. The first approach is adaptive control, which offers improved performance over fixed-gain controllers in the presence of rapidly changing turbulence. The second approach incorporated into the study is a dual-mirror system. The two mirrors are a high-bandwidth, low-actuator-stroke (tweeter) mirror and a low-bandwidth, large actuator-stroke (woofer) mirror. The woofer-tweeter combination allows for …

Subjective Audio Quality Over A Secure Ieee 802.11n Draft 2.0 Wireless Local Area Network, Benjamin W. Ramsey

Theses and Dissertations

This thesis investigates the quality of audio generated by a G.711 codec and transmission over an IEEE 802.11n draft 2.0 wireless local area network (WLAN). Decline in audio quality due to additional calls or by securing the WLAN with transport mode Internet Protocol Security (IPsec) is quantified. Audio quality over an IEEE 802.11n draft 2.0 WLAN is also compared to that of IEEE 802.11b and IEEE 802.11g WLANs under the same conditions. Audio quality is evaluated by following International Telecommunication Union Telecommunication Standardization Sector (ITU-T) Recommendation P.800, where human subjects rate audio clips recorded during various WLAN configurations. The Mean …

An Fpga-Based System For Tracking Digital Information Transmitted Via Peer-To-Peer Protocols, Karl R. Schrader

Theses and Dissertations

This thesis addresses the problem of identifying and tracking digital information that is shared using peer-to-peer file transfer and Voice over IP (VoIP) protocols. The goal of the research is to develop a system for detecting and tracking the illicit dissemination of sensitive government information using file sharing applications within a target network, and tracking terrorist cells or criminal organizations that are covertly communicating using VoIP applications. A digital forensic tool is developed using an FPGA-based embedded software application. The tool is designed to process file transfers using the BitTorrent peer-to-peer protocol and VoIP phone calls made using the Session …

Virta-Flaneurazine-Sl, Clinical Study, Collaborative Project

Dyson College- Seidenberg School of CSIS : Collaborative Projects and Presentations

This entry adheres to the use of the quad chart template to provide a succint description only of the current research project undertaken by the participants. It provides for the following information:

1. Participants and Affiliations
2. Overall Project Goals
3. Illustrative picture
4. Specific research/artistic/pedagogic foci

Programmable Media Conference - Pace, Collaborative Project

Dyson College- Seidenberg School of CSIS : Collaborative Projects and Presentations

This entry adheres to the use of the quad chart template to provide a succint description only of the current research project undertaken by the participants. It provides for the following information:

1. Participants and Affiliations
2. Overall Project Goals
3. Illustrative picture
4. Specific research/artistic/pedagogic foci

Egyptian Fractions Revisited, Olga Kosheleva, Vladik Kreinovich

Departmental Technical Reports (CS)

It is well known that the ancient Egyptians represented each fraction as a sum of unit fractions -- i.e., fractions with unit numerators; this is how they, e.g., divided loaves of bread. What is not clear is why they used this representation. In this paper, we propose a new explanation: crudely speaking, that the main idea behind the Egyptian fractions provides an optimal way of dividing the loaves. We also analyze the related properties of fractions.

A New Justification Of Wang Transform Operator In Financial Risk Analysis, Vladik Kreinovich, Hung T. Nguyen, Songsak Sriboonchitta

Departmental Technical Reports (CS)

One of the most widely used (and most successful) methods for pricing financial and insurance instruments under risk is the Wang transform method. In this paper, we provide a new explanation for the empirical success of Wang's method -- by providing a new simpler justification for the Wang transform.

Is Parallel Programming Hard, And If So, Why?, Paul E. Mckenney, Maged M. Michael, Manish Gupta, Philip William Howard, Josh Triplett, Jonathan Walpole

Computer Science Faculty Publications and Presentations

Of the 200+ parallel-programming languages and environments created in the 1990s, almost all are now defunct. Given that parallel systems are now well within the budget of the typical hobbyist or graduate student, it is not unreasonable to expect a new cohort in excess of several thousand parallel languages and environments to appear in the 2010s. If this expected new cohort is to have more practical impact than did its 1990s counterpart, a robust and widely applicable framework will be required that encompasses exactly what, if anything, is hard about parallel programming. This paper revisits the fundamental precepts of concurrent …

Integrated Cognitive Architectures: A Survey, Hui-Qing Chong, Ah-Hwee Tan, Gee-Wah Ng

Research Collection School Of Computing and Information Systems

This article aims to present an account of the state of the art research in the field of integrated cognitive architectures by providing a review of six cognitive architectures, namely Soar, ACT-R, ICARUS, BDI, the subsumption architecture and CLARION. We conduct a detailed functional comparison by looking at a wide range of cognitive components, including perception, memory, goal representation, planning, problem solving, reasoning, learning, and relevance to neurobiology. In addition, we study the range of benchmarks and applications that these architectures have been applied to. Although no single cognitive architecture has provided a full solution with the level of human …

Label Oriented Clustering For Social Network Groups, Ahmed El Kholy

Archived Theses and Dissertations

No abstract provided.

Collaborative Filtering For Domain Independent Recommendation, Rami El-Gawly

Archived Theses and Dissertations

No abstract provided.