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Articles 2191 - 2220 of 2429

Full-Text Articles in Physical Sciences and Mathematics

A Relational Database Approach For Frequent Subgraph Mining, Subhesh Kumar Pradhan Jul 2006

A Relational Database Approach For Frequent Subgraph Mining, Subhesh Kumar Pradhan

Computer Science and Engineering Theses - Archive

Data mining aims at discovering interesting and previously unknown patterns from data sets. Further more, graph-based data mining represents a collection of techniques for mining the relational aspects of data represented as a graph. Complex relationships in data can be represented using graphs and hence graph mining is appropriate for analyzing data that is rich in structural relationships. Database mining of graphs, on the other hand, aims at directly mining graphs stored in a database using SQL queries. Several SQL-based mining algorithms have been developed successfully and their efficiency and scalability have been established. One of them is HDB-Subdue which …

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Selenium Speciation Along A Groundwater Flow Path In The Carrizo Aquifer, Southeastern Texas, Usa, Rituparna Basu Jul 2006

Selenium Speciation Along A Groundwater Flow Path In The Carrizo Aquifer, Southeastern Texas, Usa, Rituparna Basu

Earth & Environmental Sciences Theses - Archive

Selenium concentration and speciation [Se (VI), Se (IV) and Se (-II)] was determined along a flow path in the Carrizo Sand aquifer (southeastern Texas). Groundwater sampling was carried out in March 2006, from ten wells located along the flow path. The collected samples were filtered through 0.45 µm filters and then acidified to pH <2 using ultra pure HCl. Analysis for Se concentration and speciation was done using selective hydride generation>- Atomic Absorption spectrometry (HG-AAS). Additional in situ measurements from each well included determination of pH, alkalinity, oxidation-reduction potential (Eh in mV), dissolved iron speciation, dissolved sulfide concentrations and dissolved manganese concentrations. Selenium concentrations in groundwaters of the Carrizo Sand aquifer are very low (i.e., nanomolal …

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Investigation Of Ruthenium (Ii) Polypyridyl Dimers As Potential Chemotherapeutic Agents, Thamara K. Janaratne Jul 2006

Investigation Of Ruthenium (Ii) Polypyridyl Dimers As Potential Chemotherapeutic Agents, Thamara K. Janaratne

Chemistry & Biochemistry Dissertations - Archive

The exploration of transition metal complexes as chemotherapeutic agents is still a relatively unexplored but promising area of research. Chapter 1 highlights the most successful anticancer drugs and potential drugs based on metal complexes, with an emphasis of platinum and ruthenium complexes. In Chapter 2, the biological activity of a series of novel ruthenium dimers is investigated with special attention given to evaluating their potential as anticancer chemotherapeutic agents. A partial list of the compound prepared includes: [Ru(bpy)(CO)2}2tpphz]4+ (74+), [Ru(bpy)(CH3CN)2}2tpphz]4+ (84+),[Ru(bpy)(C2O4)}2tpphz] (9), [Ru(bpy)(CO)(Cl)}2tpphz]2+ (102+), [(bpy)2Ru(tpphz)Ru(bpy)2]4+ (114+), [(phen)2Ru(tpphz)Ru(phen)2]4+ (124+), [(phen)2Ru(tatpp)Ru(phen)2]4+ (Pp4+), [(phen)2Ru(tatpq)Ru(phen)2]4+ (Qp4+), [(bpy)2Ru(tatpp)Ru(bpy)2]4+ (Pb4+) and [(bpy)2Ru(tatpq)Ru(bpy)2]4+ (Qb4+). Systematic changes in …

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A Graph-Based Approach For Modeling And Indexing Video Data, Jeongkyu Lee Jun 2006

A Graph-Based Approach For Modeling And Indexing Video Data, Jeongkyu Lee

Computer Science and Engineering Dissertations - Archive

With the advances in electronic imaging, storage, networking and computing, the amount of digital video has grown tremendously. The proliferation of video data has led to significant amount of research on techniques and systems for efficient video database management. In particular, extensive research has been done on video data modeling to manage and organize the data that is semantically rich and complicated. However, the enormous amount of data size and its complexity have restricted the progress on video data modeling, indexing and retrieval. In order to get around the problems, we turn to a graph theoretical approach for video database. …

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Simulation Of Sensor Responses Of Advanced Security Systems, Janakiram Natarajan Jun 2006

Simulation Of Sensor Responses Of Advanced Security Systems, Janakiram Natarajan

Computer Science and Engineering Theses - Archive

Security systems are becoming an increasingly important area of research. Advanced security detection and surveillance systems that integrates a variety of detection mechanisms, like signals from different kinds of sensors, is expected to yield more accurate assessment than any one sensor analyzed individually. Designing and investigating these systems, to date, has relied primarily on physical deployments and experimentation. While the quality of the results from such efforts is excellent, the need to work with the physical systems directly imposes a substantial research impediment. One obvious possibility for widening the scope of what can be investigated is to employ simulation as …

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Exception Handling Using Class Diversity, Qizhi Ye Jun 2006

Exception Handling Using Class Diversity, Qizhi Ye

Computer Science and Engineering Theses - Archive

Software reliability has been received more and more attention not only in mission critical system but also in commercial software system. Developing robust software must consider faults caused by abnormal situations or exceptions. Although modern programming languages like Java and C++ provide sophisticated exception handling mechanisms for detecting and handling exceptions, many potential runtime exceptions are not caught and handled because runtime exceptions could occur anywhere and could be numerous in a typical program. If an uncaught runtime exception occurs during program execution, then the execution will terminate abnormally, resulting in a system crash. The thesis proposes a framework that …

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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 …

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The Effect Of Temperature And Humidity On The Bionomics Of Six African Egg Parasitoids (Hymenoptera: Trichogrammatidae), A. Kalyebi, W. A. Overholt, F. Schulthess, J. M. Mueke, S. Sithanantham Jun 2006

The Effect Of Temperature And Humidity On The Bionomics Of Six African Egg Parasitoids (Hymenoptera: Trichogrammatidae), A. Kalyebi, W. A. Overholt, F. Schulthess, J. M. Mueke, S. Sithanantham

All Peer-Reviewed Publications

The life table statistics of six native Kenyan species/strains of Trichogramma and Trichogrammatoidea were established using a factitious host Corcyra cephalonica, Stainton (Lepidoptera: Pyralidae), at eight different temperatures (10, 15, 20, 25, 28, 30, 32 and 35°C) and two humidity levels (40-50 and 70-80%). The objective was to select insects with superior attributes for augmentative release against lepidopteran pests in horticultural crops. Both temperature and humidity affected developmental time and life table parameters of the parasitoids but temperature played a more critical role. Developmental time was inversely related to temperature. The intrinsic and finite rates of increase increased with temperature …

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Spatially Targeting Culex Quinquefasciatus Aquatic Habitats On Modified Land Cover For Implementing An Integrated Vector Management (Ivm) Program In Three Villages Within The Mwea Rice Scheme, Kenya, Benjamin G. Jacob, Josephat Shililu, Ephantus J. Muturi, Joseph M. Mwangangi, Simon M. Muriu, Jose Funes, John Githure, James L. Regens, Robert J. Novak May 2006

Spatially Targeting Culex Quinquefasciatus Aquatic Habitats On Modified Land Cover For Implementing An Integrated Vector Management (Ivm) Program In Three Villages Within The Mwea Rice Scheme, Kenya, Benjamin G. Jacob, Josephat Shililu, Ephantus J. Muturi, Joseph M. Mwangangi, Simon M. Muriu, Jose Funes, John Githure, James L. Regens, Robert J. Novak

All Peer-Reviewed Publications

Background: Continuous land cover modification is an important part of spatial epidemiology because it can help identify environmental factors and Culex mosquitoes associated with arbovirus transmission and thus guide control intervention. The aim of this study was to determine whether remotely sensed data could be used to identify rice-related Culex quinquefasciatus breeding habitats in three rice-villages within the Mwea Rice Scheme, Kenya. We examined whether a land use land cover (LULC) classification based on two scenes, IKONOS at 4 m and Landsat Thematic Mapper at 30 m could be used to map different land uses and rice planted at different …

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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 …

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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 …

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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, …

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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, …

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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 …

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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 …

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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 …

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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 …

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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 …

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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.

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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 …

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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 …

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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 …

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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 …

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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 …

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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 …

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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) …

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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 …

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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 …

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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, …

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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 …

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