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

Physical Sciences and Mathematics Commons™

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

Other

Discipline
Institution
Keyword
Publication Year
Publication
Publication Type

Articles 1921 - 1950 of 2111

Full-Text Articles in Physical Sciences and Mathematics

Studies Toward The Enantioselective Total Synthesis Of The Martinella Alkaloids, Vivek Badarinarayana Jun 2006

Studies Toward The Enantioselective Total Synthesis Of The Martinella Alkaloids, Vivek Badarinarayana

Chemistry & Biochemistry Dissertations - Archive

This dissertation consists of two parts. The first part describes the enantioselective total synthesis of martinellic acid. The Martinella alkaloids have attracted considerable attention in the synthetic community over the past few years. This interest is due in large part to their unique structure and useful biological activity (bradykinin receptor antagonist). In model systems we have successfully used the [3+2] azomethine ylide-alkene cycloaddition to construct the heterocyclic core of these alkaloids. The enantioselective approach described herein also involves the azomethine ylide-alkene cycloaddition as a key step in the total synthesis. The pyrrolo[3,2-c]quinoline core of this alkaloid was constructed in an …

Go to article

Relative Clock Drift Rate Based Secure Time Synchronization For Wireless Sensor Networks, Jae Sung Choi May 2006

Relative Clock Drift Rate Based Secure Time Synchronization For Wireless Sensor Networks, Jae Sung Choi

Computer Science and Engineering Theses - Archive

Time synchronization is critical issue to many wireless sensor network applications such that target tracking, TDMA radio scheduling, and secure localization. However, the most of existing time synchronization algorithms in wireless sensor networks did not consider malicious attacks in hostile environments. In this thesis, we propose a Relative Clock Drift Rate Based Secure Time Synchronization (RSTS) schemes to address security problems. RSTS alleviates delay attacks and incorrect time stamp transmissions caused by external or internal malicious attackers. We discuss a simple estimation technique to calculate a relative clock drift rate between sender-receiver clocks, because the estimated relative clock drift rate …

Go to article

Towards Optimum Play-Out Buffering Delay In Voice Over Ip, Ruchir Pramod Shende May 2006

Towards Optimum Play-Out Buffering Delay In Voice Over Ip, Ruchir Pramod Shende

Computer Science and Engineering Theses - Archive

Voice over Internet Protocol (VoIP) or transmission of real-time voice packets over the Internet is slowly emerging as a cost-effective alternative to the traditional Public Switched Telephone Network (PSTN). However, varying end-to-end delay and packet loss, which are inherent in a packet-switched network like the Internet, lead to relatively lower quality of VoIP calls. The call quality can be improved by adaptively adjusting the play-out buffer at the receiver to reduce the impact of the delay and jitter. A standard play-out strategy uses a weighted moving average of the mean and variance of network delay to adaptively set the play-out …

Go to article

Concept-Based Search Using Parallel Query Expansion, Rahul Rajiv Joshi May 2006

Concept-Based Search Using Parallel Query Expansion, Rahul Rajiv Joshi

Computer Science and Engineering Theses - Archive

We address the problem of irrelevant results for short queries on Web search engines. Short queries fail to provide sufficient context to disambiguate possible meanings associated with the search terms resulting in a set of irrelevant pages that the user has to filter through navigation and sometimes examination. First, we predict the potential concept topics, which are the domains for the search terms. This prediction is based on word occurrences and relationships observed in the various domains (categories) of a corpus. Next, we expand the search terms in each of the predicted domains in parallel. We then submit separate queries, …

Go to article

Ubca: A Utility Based Clustering Architecture For Peer-To-Peer Networks, Brent Lagesse May 2006

Ubca: A Utility Based Clustering Architecture For Peer-To-Peer Networks, Brent Lagesse

Computer Science and Engineering Theses - Archive

Use of the Peer-to-Peer (P2P) architecture has recently spread in popularity. File sharing and ad hoc networks have contributed to the architecture's usage. P2P generates new challenges in scalability, fairness, and quality of service. Current solutions tend to fall into two main areas: incentives and system design. Incentive-based approaches appeal to the self-interested nature of peers by requiring service to the system in order to access resources. System design includes distributed hash tables and graph-theoretical based designs which have seen some success, but also result in new problems. We introduce a Utility-Based Clustering Architecture, UBCA, designed to address scalability, fairness, …

Go to article

Alternative Architectures For Improving Document Readability, Ankur Bora May 2006

Alternative Architectures For Improving Document Readability, Ankur Bora

Computer Science and Engineering Theses - Archive

A number of tools have been developed to improve the readability of documents. These tools assist users to make changes which result in an easy to read document. Most of these tools were developed for users who work independently with little interaction with other users. However, in recent years, because of the proliferation of Internet, there has been increased collaboration between users. A user may need to share his document repositories with others so that both can benefit. Another set of users may work with information from a specific domain. These domains may be located in different geographical areas. Some …

Go to article

Anytime Top-K Queries On Exact And Fuzzy Data, Bhushan P. Chaudhari May 2006

Anytime Top-K Queries On Exact And Fuzzy Data, Bhushan P. Chaudhari

Computer Science and Engineering Theses - Archive

Top-k queries on large multi-attribute data sets are fundamental operations in information retrieval and ranking applications. In this thesis, we initiate research on the anytime behavior of top-k algorithms on exact and fuzzy data. In particular given specific topk algorithms we are interested in studying their progress towards identification of the correct result at any point of the algorithms' execution. We adopt a probabilistic approach where we seek to report at any point the scores of the top-k results the algorithm has identified, as well as associate a confidence with this prediction. Such functionality can be a valuable asset when …

Go to article

Towards A Stronger Peer-To-Peer Anonymous System, Arjun R. Nambiar May 2006

Towards A Stronger Peer-To-Peer Anonymous System, Arjun R. Nambiar

Computer Science and Engineering Theses - Archive

Anonymous communications systems on the Internet provides protection against eavesdroppers and others that seek to link users with their communications. These systems have many important applications in areas such as law enforcement, intelligence gathering, business privacy, anonymous publishing, and personal privacy. Currently deployed systems rely on a relatively small set of advertised servers to forward messages for the user. These systems can suffer from scalability problems, with potentially large bandwidth and system overhead costs, and the servers themselves can be targets of direct attacks. Peer-to-peer anonymous communications systems, such as Tarzan[1] and MorphMix [2], have been proposed as a way …

Go to article

Investigation Of Techniques To Increase The Scalability Of Graph-Based Data Mining Algorithms., Srilatha Inavolu May 2006

Investigation Of Techniques To Increase The Scalability Of Graph-Based Data Mining Algorithms., Srilatha Inavolu

Computer Science and Engineering Theses - Archive

Frequent subgraph pattern recognition and graph-based relational learning have been an emerging area of data mining research with scientific and commercial applications. At the kernel of these algorithms are the computationally-expensive graph and subgraph isomorphism tests. The graph isomorphism problem consists in deciding whether two graphs are isomorphic i.e., whether there is a one-one mapping between the vertices of the two graphs that respects the edge connections. Many graphs will be depicted quite differently but in actuality have the same inherent structure. This leads to the isomorphism problem. The graph isomorphism problem belongs to the class of NP problems and …

Go to article

Multiple Object Tracking Using Particle Filters, Hwangryol Ryu May 2006

Multiple Object Tracking Using Particle Filters, Hwangryol Ryu

Computer Science and Engineering Theses - Archive

We describe a novel extension to the Particle filter algorithm for tracking multiple objects. The recently proposed algorithms and the variants for multiple object tacking algorithms estimate multi-modal posterior distributions that potentially represent the multiple peaks (i.e., multiple tracked objects). However, the speci¯c state representation does not demonstrate birth, death and more importantly partial/complete occlusion of the objects. Furthermore, the weakness of the Particle Filter such that the representation may increasingly bias the posterior density estimates toward objects with dominant likelihood makes the multiple object tracking algorithms more di±cult. To circumvent a sample depletion problem and maintain the computational complexity …

Go to article

Supervised Learning From Embedded Subgraphs, Joseph T. Potts May 2006

Supervised Learning From Embedded Subgraphs, Joseph T. Potts

Computer Science and Engineering Dissertations - Archive

We develop a machine learning algorithm which learns rules for classification from training examples in a graph representation. However, unlike most other such algorithms which use one graph for each example, ours allows all of the training examples to be in a single, connected graph. We employ the Minimum Description Length principle to produce a novel performance metric for judging the value of a learned classification. We implement the algorithm by extending the Subdue graph-based learning system. Finally, we demonstrate the use of the new system in two different domains, earth science and homeland security.

Go to article

Conditions For Wave Propagation Along Solar Magnetic Flux Tubes, Swati Routh May 2006

Conditions For Wave Propagation Along Solar Magnetic Flux Tubes, Swati Routh

Physics Theses - Archive

There is an intimate relation between all aspects of the solar activity and the presence of solar magnetic fields. Observations showed that the magnetic field at the photospheric level consists of magnetic flux tubes, which are located at supergranule boundaries. The flux tubes interact with the solar granulation and convection and, as a result, longitudinal, transverse and torsional magnetic tube waves are generated. These waves are responsible for carrying the energy to the upper parts of the solar atmosphere and heating the atmosphere to temperatures much higher than the solar photosphere. The energy carried by transverse and torsional waves may …

Go to article

Derivation Of Generalized Lorenz Systems To Study The Onset Of Chaos In High Dimension, Dipanjan Roy May 2006

Derivation Of Generalized Lorenz Systems To Study The Onset Of Chaos In High Dimension, Dipanjan Roy

Physics Theses - Archive

This thesis provides a new method to derive high dimensional generalized Lorenz systems. Lorenz system is a celebrated nonlinear dynamical dissipative system which was originally derived by Lorenz to study chaos in weather pattern. The classical two dimensional and dissipative Rayleigh-Benard convection can be approximated by Lorenz model, which was originally derived by taking into account only the lowest three Fourier modes. Numerous attempts have been made to generalize this 3D Lorenz model as the study of this high dimensional model will pave the way to better understand the onset of chaos in high dimensional systems of current interest in …

Go to article

Power And Distortion Optimized Video Coding For Pervasive Computing Applications, Yongfang Liang Apr 2006

Power And Distortion Optimized Video Coding For Pervasive Computing Applications, Yongfang Liang

Computer Science and Engineering Dissertations - Archive

This dissertation investigates video encoding schemes for pervasive computing applications that must ensure low power consumption in addition to high compression efficiency. The contribution of the dissertation is the formulation of a theoretical problem that captures the joint optimization of power and distortion in video coding. The study of the complexity distribution of typical video encoders helps to develop a complexity-scalable video encoding architecture that includes several control parameters to adjust the power consumption of the major modules of the encoder. An analytic framework to model, control and optimize the power-rate-distortion is developed, which facilitates the development of optimization schemes …

Go to article

New Developments Of The Deformation Method, Jie Liu Apr 2006

New Developments Of The Deformation Method, Jie Liu

Mathematics Dissertations - Archive

New developments of deformation method for grid generation are presented in this work. Theorems for three different cases and different methods for implementing deformation method are presented. One of the new developments is a 3D multi-block moving grid method. In this version, a Poisson equation is solved by finite difference method to get the vector field for moving grid. Special treatment applies to the common boundary of different blocks. Another new development is a numerical method for reconstructing a given differentiable transformations by solving a system of div-curl equation directly formed from each point of the graph. The determinacy and …

Go to article

Application Of Software Engineering Best Practices And Principles To Small Development Teams, Miles Phillips Apr 2006

Application Of Software Engineering Best Practices And Principles To Small Development Teams, Miles Phillips

Computer Science and Engineering Theses - Archive

The motivation of this thesis comes from the professional experience of the author. Having worked with very small software development teams in various capacities, he realized that significant improvements could be achieved by the application of modern software engineering practices and principles. This paper is the result of researching how the principles and practices promoted by the leading software development authors can be applied to the small development team as they transition from "programming in the small" to "programming in the medium." This paper investigates the best practices and principles in various case studies with the objective to clearly define …

Go to article

The Advantages Of Implementing Software Engineering Process Models, Ricky Don Preuninger Apr 2006

The Advantages Of Implementing Software Engineering Process Models, Ricky Don Preuninger

Computer Science and Engineering Theses - Archive

The North Atlantic Treaty Organization Science Committee had discussions on the topic concerned the state of Computer Science. There were worldwide issues with the development of software, the crisis being that software projects did not seem ever to complete. The study group coined the term "software engineering" to be provocative and implying need for software manufacturing to be similar to traditional branches of engineering. In the beginning, individual programmers used whatever means worked to build software. Formal methods of design or programming did not exist. Programmers were never able to give a definitive estimate as to how long a project …

Go to article

A Performance Evaluation Of Alternate Numbering Based Xml Indexing Techniques, Chul Ho Ahn Apr 2006

A Performance Evaluation Of Alternate Numbering Based Xml Indexing Techniques, Chul Ho Ahn

Computer Science and Engineering Theses - Archive

Since XML became a standard of representing semi-structured data and exchanging format over the web, the sheer volume of XML data has become larger. While relational database represents data as a structured format, XML represents data in a self-describing way as a hierarchical tree structure. For expediting query processing over XML, many different types of indexing techniques have emerged. We will focus on numbering-based indexing techniques in this thesis. We will present performance comparison according to different XPath queries among three distinct numbering based XML indexing named GENE (Generic numbering based), XISS (Range based numbering), and XACC (Dimension based numbering) …

Go to article

Monitorexplorer: A State-Space Exploration Based Tool To Test Java Monitors Implementations, Vidur Gupta Apr 2006

Monitorexplorer: A State-Space Exploration Based Tool To Test Java Monitors Implementations, Vidur Gupta

Computer Science and Engineering Theses - Archive

A monitor is a concurrency construct that encapsulates data. There are many application classes which are written using the Java Monitors and these are difficult to test due to the inherent complexities of the concurrent programs. The key challenge is to be able to trace all possible execution paths and then able to reproduce them for regression testing. Our work explores the state-space of the monitor application. The state space is explored in the depth first fashion. At each state the next possible transition is executed. This process is repeated till a duplicate or invalid state is detected. The key …

Go to article

Bridging Two Grids: The Sam-Grid/Lcg Integration Project, Tummalapalli Sudhamsh Reddy Apr 2006

Bridging Two Grids: The Sam-Grid/Lcg Integration Project, Tummalapalli Sudhamsh Reddy

Computer Science and Engineering Theses - Archive

SAM-Grid is an integrated data, job, and information management system. SAM-Grid addresses the distributed computing needs of the Dzero experiment at Fermi National Accelerator Laboratory, Batavia, IL. The system typically relies on SAM-Grid specific services deployed at the remote sites in order to manage the computing and storage resources. Such deployment requires special agreements with each resource provider, and it is a labor intensive process. Some members of the Dzero VO also have access to computing resources through the Large Hydron Collider Computing Grid (LCG) infrastructure. Therefore, Dzero users can enter into resource sharing agreements and deployment of standard middleware …

Go to article

Preparation And Characterization Of Hard Magnetic Nanoparticles, Daren Li Apr 2006

Preparation And Characterization Of Hard Magnetic Nanoparticles, Daren Li

Physics Theses - Archive

Hard-magnetic nanoparticles with uniform size distribution have attracted huge attention in the past several years because of their unique magnetic properties and potential for many applications such as high density recording media, exchange-coupled nanocomposite permanent magnets and biomedical applications. In this thesis, preparation and characterization of hard magnetic nanoparticles with different sizes are reported. Monodisperse FePt nanoparticles with face-centered cubic (fcc) structure were synthesized by chemical solution method and particle diameter was tuned from 2 to 15 nm by varying reaction conditions. Monodisperse hard-magnetic FePt nanoparticles with ordered face-centered tetragonal (fct) structure were prepared by the salt-matrix annealing technique. Morphological, …

Go to article

Creation Of Crm Selection Methodology For The Aerospace & Defense Industry, Reggie Arsenault Feb 2006

Creation Of Crm Selection Methodology For The Aerospace & Defense Industry, Reggie Arsenault

Regis University Student Publications (comprehensive collection)

The Aerospace and Defense Industry is rebounding from one of the worst financial downturns in the history of the market. What has emerged is a realization that the future for Aerospace and Defense manufacturing requires a focus on “services†versus supplying high quality products alone. In order to support such a complex offering of products and services, manufacturing organizations in the Aerospace and Defense Industry must migrate to a customer-centric business structure within their people, processes, and tools. To support the shift, companies must deploy a robust, enterprise, CRM (Customer Relationship Management) technology. The difficulty is in the selection process …

Go to article

Projects That Assist With Content In A Traditional Organic Chemistry Course, John J. Esteb, John R. Magers, Luanne Mcnulty, Anne M. Wilson Jan 2006

Projects That Assist With Content In A Traditional Organic Chemistry Course, John J. Esteb, John R. Magers, Luanne Mcnulty, Anne M. Wilson

Scholarship and Professional Work - LAS

Projects that engage undergraduate students in content-based courses, such as organic chemistry, must relate to the material and provide useful tools for the divergent needs of the students. There are few examples of these types of projects in the literature. Herein, we describe two projects, the reaction notebook and the end-of-semester synthesis activity. Each project is designed to stimulate student ownership of the material and leads to engagement with the content of the course.

Go to article

You Should Run For Office (Video), Kevin O'Brien, Grace Drake Jan 2006

You Should Run For Office (Video), Kevin O'Brien, Grace Drake

All Maxine Goodman Levin School of Urban Affairs Publications

No abstract provided.

Go to article

Use Of Bootable Linux Cds For The Delivery Of Educational Course Content, Craig Valli Jan 2006

Use Of Bootable Linux Cds For The Delivery Of Educational Course Content, Craig Valli

Research outputs pre 2011

This paper outlines the processes involved in creating and using bootable Linux/Knoppix compact discs (CDs) as a means of delivering course content to students. An outline of experiences in using these CDs to deliver courses in totally on-line mode is also given.

Go to article

Structural Evolution And Vorticity Of Flow During Extrusion And Exhumation Of The Greater Himalayan Slab, Mount Everest Massif, Tibet/Nepal: Implications For Orogen-Scale Flow Partitioning, M. J. Jessup, R. D. Law, M. P. Searle, Mary S. Hubbard Jan 2006

Structural Evolution And Vorticity Of Flow During Extrusion And Exhumation Of The Greater Himalayan Slab, Mount Everest Massif, Tibet/Nepal: Implications For Orogen-Scale Flow Partitioning, M. J. Jessup, R. D. Law, M. P. Searle, Mary S. Hubbard

Geosciences Faculty Publications

The Greater Himalayan Slab (GHS) is composed of a north-dipping anatectic core, bounded above by the South Tibetan detachment system (STDS_ and below by the Main Central thrust zone (MCTZ). Assuming simultaneous movement on the MCTZ and STDS, the GHS can be modelled as a southward-extruding wedge or channel. New insights into extrusion-related flow with the GHS emerge from detailed kinematic and vorticity analyses in the Everest region. At the highest structural levels, mean kinematic vorticity number (Wm) estimates of 0.74-0.91 (c. 45-28% pure shear) were obtained from sheared Tethyan limestone and marble from the Yellow Band on Mount Everest. …

Go to article

Interactive Animated Concept Map Generation - Using Dynamic Animations, Suneel Vana Dec 2005

Interactive Animated Concept Map Generation - Using Dynamic Animations, Suneel Vana

Computer Science and Engineering Theses - Archive

We present a visualization tool, which is useful for the illustration of educational concepts using interactive animated concept maps. This system serves as a presentation tool which provides a collection of multimedia elements (images, animations, audios clips and video clips), a collection of animated presentation templates and an interface by using which users can retrieve the multimedia elements from the multimedia database and generate the dynamic animations by placing the selected elements into the placeholders of the templates. The system generates the animated presentation by replacing embedded multimedia objects and their properties as desired by its users. A multimedia information …

Go to article

On The Existence And Stability Of Carbon -Based Silicon Fullerenes -A Density Functional Theoretic Study, Aravind Srinivasan Dec 2005

On The Existence And Stability Of Carbon -Based Silicon Fullerenes -A Density Functional Theoretic Study, Aravind Srinivasan

Physics Theses - Archive

The electronic and geometric properties of silicon-carbon fullerene-like nanostructures with two, four, six, twenty and twenty four carbon atoms on the surface of the Si60 cages by substitution, as well as inside the cage at various symmetry orientations have been studied within the generalized gradient approximation to density functional theory (GGA-DFT). The Perdew-Wang 91 (PW91) functional has been used to treat exchange and correlation energies. Full geometry and spin optimizations have been performed using Gaussian 03 suite of programs and the LANL2DZ basis set. Thus for the silicon atom, the Hay-Wadt pseudopotential with the associated basis set are used for …

Go to article

Monitoring Health By Detecting Drifts And Outliers In Patterns Of An Inhabitant In A Smart Home, Gaurav Jain Dec 2005

Monitoring Health By Detecting Drifts And Outliers In Patterns Of An Inhabitant In A Smart Home, Gaurav Jain

Computer Science and Engineering Theses - Archive

The elderly, along with people with disabilities or chronic illness, are most often dependent on some kind of formal or informal care. They are forced to move to a place where they can be cared for. Automatic health monitoring allows them to maintain their independence and continue living at home longer by continuously providing key health and activity information to caregivers. In this thesis, we present a novel technique, called the Health Monitoring System (HMS), which is a data-driven automated monitoring system for detecting changes in the patterns of activities/inactivity, health data and the living environment. HMS classifies these changes …

Go to article

Infosearch: A System For Searching And Retrieving Documents Using Complex Queries, Nikhil Deshpande Dec 2005

Infosearch: A System For Searching And Retrieving Documents Using Complex Queries, Nikhil Deshpande

Computer Science and Engineering Theses - Archive

The colossal amount of information available online has resulted in overloading users who need to navigate this information for their routine requirements. Although search engines have been effective in reducing this information overload, they support only queries involving keywords and Boolean operators. There are certain application domains where more expressive ways of searching are necessary. Consider searching a full-text patent database for documents containing more than n occurrences of a pattern, or for documents that have a particular pattern followed by another pattern within a specified interval. Such complex patterns involving pattern frequency and sequence, as well as patterns involving …

Go to article

First Prev Next Last