Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 14 of 14

Full-Text Articles in Physical Sciences and Mathematics

Trust-Based Service Selection, Zainab Aljazzaf Nov 2011

Trust-Based Service Selection, Zainab Aljazzaf

Electronic Thesis and Dissertation Repository

Service Oriented Architecture (SOA) is an architectural style that builds enterprise solutions based on services. In SOA, the lack of trust between different parties affects the adoption of such architecture. Trust is as significant a factor for successful online interactions as it is in real life communities, and consequently, it is an important factor that is used as a criterion for service selection. In the context of online services and SOA, the literature shows that the field of trust is not mature. Trust definition and the consideration of the essentials of trust aspects do not reflect the true nature of …


Classic Mosaics And Visual Correspondence Via Graph-Cut Based Energy Optimization, Yu Liu Oct 2011

Classic Mosaics And Visual Correspondence Via Graph-Cut Based Energy Optimization, Yu Liu

Electronic Thesis and Dissertation Repository

Computer graphics and computer vision were traditionally two distinct research fields focusing on opposite topics. Lately, they have been increasingly borrowing ideas and tools from each other. In this thesis, we investigate two problems in computer vision and graphics that rely on the same tool, namely energy optimization with graph cuts.

In the area of computer graphics, we address the problem of generating artificial classic mosaics, still and animated. The main purpose of artificial mosaics is to help a user to create digital art. First we reformulate our previous static mosaic work in a more principled global optimization framework. Then, …


Three-Dimensional Modeling Of Electrostatic Precipitator Using Hybrid Finite Element - Flux Corrected Transport Technique, Niloofar Farnoosh Oct 2011

Three-Dimensional Modeling Of Electrostatic Precipitator Using Hybrid Finite Element - Flux Corrected Transport Technique, Niloofar Farnoosh

Electronic Thesis and Dissertation Repository

This thesis presents the results of a three-dimensional simulation of the entire precipitation process inside a single-electrode one-stage electrostatic precipitator (ESP). The model was designed to predict the motion of ions, gas and solid particles. The precipitator consists of two parallel grounded collecting plates with a corona electrode mounted at the center, parallel to the plates and excited with a high dc voltage. The complex mutual interaction between the three coexisting phenomena of electrostatic field, fluid dynamics and the particulate transport, which affect the ESP process, were taken into account in all the simulations. The electrostatic field and ionic space …


Addressing Computational Complexity Of High Speed Distributed Circuits Using Model Order Reduction, Ehsan Rasekh Sep 2011

Addressing Computational Complexity Of High Speed Distributed Circuits Using Model Order Reduction, Ehsan Rasekh

Electronic Thesis and Dissertation Repository

Advanced in the fabrication technology of integrated circuits (ICs) over the last couple of years has resulted in an unparalleled expansion of the functionality of microelectronic systems. Today’s ICs feature complex deep-submicron mixed-signal designs and have found numerous applications in industry due to their lower manufacturing costs and higher performance levels. The tendency towards smaller feature sizes and increasing clock rates is placing higher demands on signal integrity design by highlighting previously negligible interconnect effects such as distortion, reflection, ringing, delay, and crosstalk. These effects if not predicted in the early stages of the design cycle can severely degrade circuit …


Improving Search Engine Results By Query Extension And Categorization, Guo Mei Sep 2011

Improving Search Engine Results By Query Extension And Categorization, Guo Mei

Electronic Thesis and Dissertation Repository

Since its emergence, the Internet has changed the way in which information is distributed and it has strongly influenced how people communicate. Nowadays, Web search engines are widely used to locate information on the Web, and online social networks have become pervasive platforms of communication.

Retrieving relevant Web pages in response to a query is not an easy task for Web search engines due to the enormous corpus of data that the Web stores and the inherent ambiguity of search queries. We present two approaches to improve the effectiveness of Web search engines. The first approach allows us to retrieve …


Advances In Graph-Cut Optimization: Multi-Surface Models, Label Costs, And Hierarchical Costs, Andrew T. Delong Sep 2011

Advances In Graph-Cut Optimization: Multi-Surface Models, Label Costs, And Hierarchical Costs, Andrew T. Delong

Electronic Thesis and Dissertation Repository

Computer vision is full of problems that are elegantly expressed in terms of mathematical optimization, or energy minimization. This is particularly true of "low-level" inference problems such as cleaning up noisy signals, clustering and classifying data, or estimating 3D points from images. Energies let us state each problem as a clear, precise objective function. Minimizing the correct energy would, hypothetically, yield a good solution to the corresponding problem. Unfortunately, even for low-level problems we are confronted by energies that are computationally hard—often NP-hard—to minimize. As a consequence, a rather large portion of computer vision research is dedicated to proposing …


Active Learning With Generalized Queries, Jun Du Sep 2011

Active Learning With Generalized Queries, Jun Du

Electronic Thesis and Dissertation Repository

We study active learning with generalized queries in the thesis.

In contrast to supervised learning, active learning can usually achieve the same predictive accuracy with much fewer labeled training examples, thus significantly reducing the labeling cost. However, previous studies of active learning mostly assume that the learner can only ask specific queries (i.e., require labels for specific examples by providing all feature values). For instance, if the task is to predict osteoarthritis based on a patient data set with 30 features, the previous active learners could only ask the specific queries as: does this patient have osteoarthritis, if ID is …


Solving Polynomial Systems Via Triangular Decomposition, Changbo Chen Aug 2011

Solving Polynomial Systems Via Triangular Decomposition, Changbo Chen

Electronic Thesis and Dissertation Repository

Finding the solutions of a polynomial system is a fundamental problem with numerous applications in both the academic and industrial world. In this thesis, we target on computing symbolically both the real and the complex solutions of nonlinear polynomial systems with or without parameters. To this end, we improve existing algorithms for computing triangular decompositions. Based on that, we develop various new tools for solving polynomial systems and illustrate their effectiveness by applications.

We propose new algorithms for computing triangular decompositions of polynomial systems incrementally. With respect to previous works, our improvements are based on a weakened notion of a …


Some Single And Combined Operations On Formal Languages: Algebraic Properties And Complexity, Bo Cui Aug 2011

Some Single And Combined Operations On Formal Languages: Algebraic Properties And Complexity, Bo Cui

Electronic Thesis and Dissertation Repository

In this thesis, we consider several research questions related to language operations in the following areas of automata and formal language theory: reversibility of operations, generalizations of (comma-free) codes, generalizations of basic operations, language equations, and state complexity.

Motivated by cryptography applications, we investigate several reversibility questions with respect to the parallel insertion and deletion operations. Among the results we obtained, the following result is of particular interest. For languages L1, L2Σ, if L2 satisfies the condition L2ΣL2 ∩ Σ+L2Σ+ = ∅, then …


Workflow-Net Based Cooperative Multi-Agent Systems, Yehia T. Kotb Aug 2011

Workflow-Net Based Cooperative Multi-Agent Systems, Yehia T. Kotb

Electronic Thesis and Dissertation Repository

Workflow-nets are mathematical frameworks that are used to formally describe, model and implement workflows. First, we propose critical section workflow nets (abbreviated WFCSnet). This framework allows feedbacks in workflow systems while ensuring the soundness of the workflow. Feedback is generally not recommended in workflow systems as they threaten the soundness of the system. The proposed WFCSnet allows safe feedback and limits the maximum number of activities per workflow as required. A theorem for soundness of WFCSnet is presented. Serializability, Separability, Quasi-liveness and CS-Properties of WFCSnet are examined and some theorems and lemmas are proposed to mathematically formalize them. In this …


Models, Techniques, And Metrics For Managing Risk In Software Engineering, Andriy Miranskyy Jun 2011

Models, Techniques, And Metrics For Managing Risk In Software Engineering, Andriy Miranskyy

Electronic Thesis and Dissertation Repository

The field of Software Engineering (SE) is the study of systematic and quantifiable approaches to software development, operation, and maintenance. This thesis presents a set of scalable and easily implemented techniques for quantifying and mitigating risks associated with the SE process. The thesis comprises six papers corresponding to SE knowledge areas such as software requirements, testing, and management. The techniques for risk management are drawn from stochastic modeling and operational research.

The first two papers relate to software testing and maintenance. The first paper describes and validates novel iterative-unfolding technique for filtering a set of execution traces relevant to a …


Finding Faulty Functions From The Traces Of Field Failures, Syed Shariyar Murtaza Mar 2011

Finding Faulty Functions From The Traces Of Field Failures, Syed Shariyar Murtaza

Electronic Thesis and Dissertation Repository

Corrective maintenance, which rectifies field faults, consumes 30-60% time of software maintenance. Literature indicates that 50% to 90% of the field failures are rediscoveries of previous faults, and that 20% of the code is responsible for 80% of the faults. Despite this, identification of the location of the field failures in system code remains challenging and consumes substantial (30-40%) time of corrective maintenance. Prior fault discovery techniques for field traces require many pass-fail traces, discover only crashing failures, or identify faulty coarse grain code such as files as the source of faults. This thesis (which is in the integrated article …


Architecture Supporting Computational Trust Formation, Chern Har Yew Feb 2011

Architecture Supporting Computational Trust Formation, Chern Har Yew

Electronic Thesis and Dissertation Repository

Trust is a concept that has been used in computing to support better decision making. For example, trust can be used in access control. Trust can also be used to support service selection. Although certain elements of trust such as reputation has gained widespread acceptance, a general model of trust has so far not seen widespread usage. This is due to the challenges of implementing a general trust model. In this thesis, a middleware based approach is proposed to address the implementation challenges.

The thesis proposes a general trust model known as computational trust. Computational trust is based on research …


Algorithmic Contributions To The Theory Of Regular Chains, Wei Pan Jan 2011

Algorithmic Contributions To The Theory Of Regular Chains, Wei Pan

Electronic Thesis and Dissertation Repository

Regular chains, introduced about twenty years ago, have emerged as one of the major

tools for solving polynomial systems symbolically. In this thesis, we focus on different

algorithmic aspects of the theory of regular chains, from theoretical questions to high-

performance implementation issues.

The inclusion test for saturated ideals is a fundamental problem in this theory.

By studying the primitivity of regular chains, we show that a regular chain generates

its saturated ideal if and only if it is primitive. As a result, a family of inclusion tests

can be detected very efficiently.

The algorithm to compute the regular GCDs …