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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
221

Kulturmiljöhänsyn inom skogsbruket : En studie om fornlämningar och gränsmärken

Hägglund, Julia January 2012 (has links)
Bakgrund      Skogsmaskiner har under många år förstört både fornlämningar och gränsmärken. Idén till databasen/tjänsten uppkom av egna erfarenheter vid en förrättning, där flertalet gränsmärken hade blivit överkörda av skogsmaskiner. Syfte              Examensarbetets syfte är att lyfta fram en ny idé för att minska skadorna på fornlämningar och gränsmärken som skogsmaskiner orsakar, samt hur lägesnoggrannheten påverkar den nya tjänstens ändamål. Metod           Examensarbetet består av en litteraturstudie med syfte att besvara och ge en bakgrund till problemställningen. För att undersöka hur vanligt det är att lantmätare/mätingenjörer stöter på att gränsmärken blivit skadade av skogsmaskiner genomfördes en enkätundersökning. För en djupare inblick av lägesnoggrannheten på utrustningen i skogsmaskiner och vilken kvalitet på koordinaterna som krävs för en mer ändamålsenligt tjänst gjordes en intervjustudie. Slutsats         De uppgifter som finns tillängliga idag ska vara användbara när det gäller fornlämningar, för en ändamålsenlig tjänst som ska fungera ute i skogen där lägesnoggrannheten inte alltid är den bästa. Däremot är kvaliteten på gränspunkter i DRK inte helt perfekt för att kunna användas. / Background  Forest machines has for many years destroyed both ancient monuments and boundary marks. The Idea for the database/service grew out of personal experience at a land parceling ceremony, where most boundary markings had been run over by forest machinery. Objective      Purpose of this thesis is to present a new idea to reduce the damage to ancient monuments and boundary marks that forestry machinery causes, and how positional accuracy affects the new service use. Method         The thesis consists of a literature study aimed to answer and give a background to the issue. To investigate how common, surveyors come across that boundary markings are damaged by forest machines a questionnaire survey was made. For a deeper insight of the positional accuracy and quality of coordinates required for a more appropriate service, an interview study was made. Conclusion    The information available today should be useful in the case of ancient monuments, for an efficient service that will work in the woods where positional accuracy is not always the best. However, the quality of the boundary points in the DRK may not be perfect for use.
222

Development and Engineering Application of Flat Shell Element by the Vector Form Intrinsic Finite Element Method

Chung, Pei-yin 30 August 2010 (has links)
Abstract This study focuses on the development of a plate-shell element using the vector form intrinsic finite element (VFIFE) method to analyze the structural behavior of thin shell structure subjected to various exerting forces. The shell element employed here is the flat three-node triangular shell element proposed by Bathe and Ho, which is obtained by superimposing CST (constant strain triangle) element with DKT (discrete Kirchhoff theory) triangular plate element. The nodal coordinates, displacements, rotations, and the motion equations of the structure are defined in a fixed global set of coordinates. The strains of the shell element, the element internal nodal forces and the element stiffness matrix are defined in terms of co-rotational coordinates, which are corresponding to the configuration of the shell element. Based on the co-rotational coordinate principle, the nodal displacement between two adjacent time steps can be separated into displacements induced from rigid body motion or deformation, and the incremental internal nodal forces can also be obtained. Finally, following the Newton's 2nd law, the equations of motion can be built to analyze the dynamic responses of thin shell structures. The theory derived in this study, were further verified to be able to simulate the behavior of thin shell structures subjected to both static and dynamic loadings. This new analytical model was proved to be an effective tool that can be an alternertive to traditional finite element procedure to solve for complicated engineering problems in thin shell structures.
223

三次元一般曲線座標系に対するCIP法粘性流解法

高下, 和浩, KOHGE, Kazuhiro, 峯村, 吉泰, MINEMURA, Kiyoshi, 内山, 知実, UCHIYAMA, Tomomi 03 1900 (has links)
No description available.
224

Some Topics in Roc Curves Analysis

Huang, Xin 07 May 2011 (has links)
The receiver operating characteristic (ROC) curves is a popular tool for evaluating continuous diagnostic tests. The traditional definition of ROC curves incorporates implicitly the idea of "hard" thresholding, which also results in the empirical curves being step functions. The first topic is to introduce a novel definition of soft ROC curves, which incorporates the idea of "soft" thresholding. The softness of a soft ROC curve is controlled by a regularization parameter that can be selected suitably by a cross-validation procedure. A byproduct of the soft ROC curves is that the corresponding empirical curves are smooth. The second topic is on combination of several diagnostic tests to achieve better diagnostic accuracy. We consider the optimal linear combination that maximizes the area under the receiver operating characteristic curve (AUC); the estimates of the combination's coefficients can be obtained via a non-parametric procedure. However, for estimating the AUC associated with the estimated coefficients, the apparent estimation by re-substitution is too optimistic. To adjust for the upward bias, several methods are proposed. Among them the cross-validation approach is especially advocated, and an approximated cross-validation is developed to reduce the computational cost. Furthermore, these proposed methods can be applied for variable selection to select important diagnostic tests. However, the above best-subset variable selection method is not practical when the number of diagnostic tests is large. The third topic is to further develop a LASSO-type procedure for variable selection. To solve the non-convex maximization problem in the proposed procedure, an efficient algorithm is developed based on soft ROC curves, difference convex programming, and coordinate descent algorithm.
225

Development of a micro-milling force model and subsystems for miniature Machine Tools (mMTs)

Goo, Chan-Seo 29 July 2011 (has links)
Nowadays, the need for three-dimensional miniaturized components is increasing in many areas, such as electronics, biomedics, aerospace and defence, etc. To support the demands, various micro-scale fabrication techniques have been further introduced and developed over the last decades, including micro-electric-mechanical technologies (MEMS and LIGA), laser ablation, and miniature machine tools (mMTs). Each of these techniques has its own benefits, however miniature machine tools are superior to any others in enabling three-dimensional complex geometry with high relative accuracy, and the capability of dealing with a wide range of mechanical materials. Thus, mMTs are emerging as a promising fabrication process. In this work, various researches have been carried out based on the mMTs. The thesis presents micro-machining, in particular, micro-milling force model and three relevant subsystems for miniature machine tools (mMTs), to enhance machining productivity/efficiency and dimensional accuracy of machined parts. The comprehensive force model that predicts micro-endmilling dynamics has been developed. Unlike conventional macro-machining, the cutting mechanism in micro-machining is complex with high level of non-linearity due to the combined effects of edge radius, size, and minimum chip thickness effect, etc., resulting in no chip formation when the chip thickness is below the minimum chip forming thickness. Instead, part of the work material deforms plastically under the edge of a tool and the rest of the material recovers elastically. The developed force model for micro-endmilling is effective to understand the micro-machining process. As a result, the micro-endmilling force model is helpful to improve the quality of machined parts. In addition, three relevant subsystems which deliver maximum machining productivity and efficiency are also introduced. Firstly, ultrasonic atomization-based cutting fluid application system is introduced. During machining, cutting fluid is required at the cutting zone for cooling and lubricating the cutting tool against the workpiece. Improper cutting fluid application leads to significantly increased tool wear, and which results in overall poor machined parts quality. For the micro-machining, conventional cooling methods using high pressure cutting fluid is not viable due to the potential damage and deflection of weak micro-cutting tools. The new atomization-based cutting fluids application technique has been proven to be quite effective in machinability due to its high level of cooling and lubricating. Secondly, an acoustic emission (AE)-based tool tip positioning method is introduced. Tool tip setting is one of the most important factors to be considered in the CNC machine tool. Since several tools with different geometries are employed during machining, overall dimensional accuracy of the machined parts are determined by accurate coordinates of each tool tip. In particular, tool setting is more important due to micro-scale involved in micro-machining. The newly developed system for tool tip positioning determines the accurate coordinates of the tool tip through simple and easy manipulation. At last, with the advance of the 3D micro-fabrication technologies, the machinable miniaturized components are getting complex in geometry, leading to increased demand on dimensional quality control. However, the system development for micro-scale parts is slow and difficult due to complicated detection devices, algorithm, and fabrication of a micro-probe. Consequently, the entire dimensional probing system tends to become bulky and expensive. A new AE-based probing system with a wire-based probe was developed to address this issue with reduced cost and size, and ease of application. / Graduate
226

Ad Hoc Packet Routing Simulation And Tactical Picture Display Tool For Navy

Aymak, Onur 01 August 2004 (has links) (PDF)
The importance of communication is vital in wartime. The capability of having all the position information of the allied and enemy forces in a single Tactical Information Display System (TIDS), maintains a great advantage for deciding what to do before the enemy reacts. A Naval Information Distributing System (NIDS) is developed for building an effective communication infrastructure between the war ships. In the designed network, besides the mobile platforms (ships), some fixed platforms (land stations) are used to transfer the information coming from these mobile platforms to all the other platforms. To demonstrate the performance and effectiveness of the Naval Information Distribution System, a discrete event simulation model is developed on a Geographic Information System. The goal of this thesis is to describe and experimentally evaluate an effective and feasible information sharing and routing system for Navy.
227

Mechanistic modeling of evaporating thin liquid film instability on a bwr fuel rod with parallel and cross vapor flow

Hu, Chih-Chieh 20 January 2009 (has links)
This work has been aimed at developing a mechanistic, transient, 3-D numerical model to predict the behavior of an evaporating thin liquid film on a non-uniformly heated cylindrical rod with simultaneous parallel and cross flow of vapor. Interest in this problem has been motivated by the fact that the liquid film on a full-length boiling water reactor fuel rod may experience significant axial and azimuthal heat flux gradients and cross flow due to variations in the thermal-hydraulic conditions in surrounding subchannels caused by proximity to inserted control blade tip and/or the top of part-length fuel rods. Such heat flux gradients coupled with localized cross flow may cause the liquid film on the fuel rod surface to rupture, thereby forming a dry hot spot. These localized dryout phenomena can not be accurately predicted by traditional subchannel analysis methods in conjunction with empirical dryout correlations. To this end, a numerical model based on the Level Contour Reconstruction Method was developed. The Standard k- turbulence model is included. A cylindrical coordinate system has been used to enhance the resolution of the Level Contour Reconstruction Model. Satisfactory agreement has been achieved between the model predictions and experimental data. A model of this type is necessary to supplement current state-of-the-art BWR core thermal-hydraulic design methods based on subchannel analysis techniques coupled with empirical dry out correlations. In essence, such a model would provide the core designer with a "magnifying glass" by which the behavior of the liquid film at specific locations within the core (specific axial node on specific location within a specific bundle in the subchannel analysis model) can be closely examined. A tool of this type would allow the designer to examine the effectiveness of possible design changes and/or modified control strategies to prevent conditions leading to localized film instability and possible fuel failure.
228

Uma arquitetura para coordenar a interação de agentes na internet / An architecture to coordinate the interaction of agents in the internet

Cazella, Silvio Cesar January 1997 (has links)
O grande salto tecnológico ocorrido nos últimos decênios em áreas como a informática e as telecomunicações já começa a causar uma verdadeira revolução social. Com o advento da Internet, a possibilidade de substituir a presença física de pessoas por assistentes inteligentes ou agentes é uma realidade que começa a tomar forma. O objetivo principal deste trabalho é definir como deve ser feita a interação entre agentes, nas sociedades de agentes dentro da Internet. Para tanto, é apresentada uma proposta de arquitetura geral para coordenar a interação de agentes na Internet, de forma a possibilitar, entre outros, a localização de agentes, a conexão entre os agentes, a identificação de agentes (nomes de agentes, função e endereços destes na rede) sem que ocorra a repetição de nomes na sociedade, a entrada e saída de agentes da sociedade, a troca de mensagens entre os agentes e a procura de agentes com determinadas características. Inicialmente, é apresentada uma visão geral sobre Inteligência Artificial Distribuída, área em que o trabalho se insere, e alguns exemplos de aplicações agentes. A seguir, as principais características da linguagem Java são introduzidas, por ser a linguagem utilizada nas implementações realizadas. Estas implementações foram feitas, a nível de protótipos, para permitir a obtenção de experiência no trabalho com agentes. Toda a programação destes agentes foi feita utilizando a linguagem Java, e a sua escolha como linguagem para estas implementações, foi feita devido a características próprias. Por exemplo. a linguagem Java é independente da plataforma de trabalho, o que no caso de programação para Internet, torna-se um característica muito desejável. Após, dois sistemas para o desenvolvimento de agentes na Internet são: apresentados em suas principais características do ponto de vista da arquitetura geral. Estes sistemas são o SodaBot e o sistema Java Agent Template. Este último totalmente implementado com a utilização da linguagem Java. Finalmente, apresenta-se em detalhes a arquitetura proposta, com um exemplo de utilização e perspectivas para a continuação do trabalho. O resultado obtido com todos os estudos realizados diz respeito a proposta de uma arquitetura que tem por objetivo permitir coordenar a interação entre os agentes que vierem a ser implementados na Internet. Toda a proposta foi acompanhada por estudos reais da viabilidade da implementação futura da arquitetura. / Technological breakthroughs which occurred in the last decades in areas such as Computer Science and Telecommunications have started to cause an undeniable social revolution. With the Internet, the possibility of replacing the physical presence of people by intelligent assistants or agents is now becoming a reality. This thesis aims at defining how the interaction among agents in the Internet should be achieved. An architecture to coordinate the interaction of agents in the Internet is presented, so as to make it possible, among other things, the localization of agents, the connection among agents, the identification of agents (their names, function, and addresses in the net), the way in and the way out of a gents of the society, the exchange of messages among agents and the search for agents with specific characteristics. First, a general view on Distributed Artificial Intelligence, the area in which this work is inserted, and some examples of agents are given. Next, the main characteristics of the Java language are introduced, since it is the language used in the implementations carried out. These implementations accomplished were prototypes which aim at gaining experience in the work with agents. All the programming of these a gents was carried out using the Java language, which was chosen for these implementations due to its characteristics. For example, the Java lan guage is Architecture Neutral, which in the case of programming for the Internet, becomes very desirable. After that, the main characteristics of two systems for the development of agents in the Internet, concerning their general architecture, were presented. These systems are SodaBot and Java Agent Template, the latter being totally implemented in the Java language. Finally, the architecture which was proposed is described in detail with an example of utilization and perspectives for a continuation of the work. The result obtained from this work is related to the proposal of an architecture which aims at making it possible to coordinate the interaction among agents which will be implemented in the Internet. The entire proposal was accompanied by studies of the feasibility of a future implementation of this architecture.
229

Uma arquitetura para coordenar a interação de agentes na internet / An architecture to coordinate the interaction of agents in the internet

Cazella, Silvio Cesar January 1997 (has links)
O grande salto tecnológico ocorrido nos últimos decênios em áreas como a informática e as telecomunicações já começa a causar uma verdadeira revolução social. Com o advento da Internet, a possibilidade de substituir a presença física de pessoas por assistentes inteligentes ou agentes é uma realidade que começa a tomar forma. O objetivo principal deste trabalho é definir como deve ser feita a interação entre agentes, nas sociedades de agentes dentro da Internet. Para tanto, é apresentada uma proposta de arquitetura geral para coordenar a interação de agentes na Internet, de forma a possibilitar, entre outros, a localização de agentes, a conexão entre os agentes, a identificação de agentes (nomes de agentes, função e endereços destes na rede) sem que ocorra a repetição de nomes na sociedade, a entrada e saída de agentes da sociedade, a troca de mensagens entre os agentes e a procura de agentes com determinadas características. Inicialmente, é apresentada uma visão geral sobre Inteligência Artificial Distribuída, área em que o trabalho se insere, e alguns exemplos de aplicações agentes. A seguir, as principais características da linguagem Java são introduzidas, por ser a linguagem utilizada nas implementações realizadas. Estas implementações foram feitas, a nível de protótipos, para permitir a obtenção de experiência no trabalho com agentes. Toda a programação destes agentes foi feita utilizando a linguagem Java, e a sua escolha como linguagem para estas implementações, foi feita devido a características próprias. Por exemplo. a linguagem Java é independente da plataforma de trabalho, o que no caso de programação para Internet, torna-se um característica muito desejável. Após, dois sistemas para o desenvolvimento de agentes na Internet são: apresentados em suas principais características do ponto de vista da arquitetura geral. Estes sistemas são o SodaBot e o sistema Java Agent Template. Este último totalmente implementado com a utilização da linguagem Java. Finalmente, apresenta-se em detalhes a arquitetura proposta, com um exemplo de utilização e perspectivas para a continuação do trabalho. O resultado obtido com todos os estudos realizados diz respeito a proposta de uma arquitetura que tem por objetivo permitir coordenar a interação entre os agentes que vierem a ser implementados na Internet. Toda a proposta foi acompanhada por estudos reais da viabilidade da implementação futura da arquitetura. / Technological breakthroughs which occurred in the last decades in areas such as Computer Science and Telecommunications have started to cause an undeniable social revolution. With the Internet, the possibility of replacing the physical presence of people by intelligent assistants or agents is now becoming a reality. This thesis aims at defining how the interaction among agents in the Internet should be achieved. An architecture to coordinate the interaction of agents in the Internet is presented, so as to make it possible, among other things, the localization of agents, the connection among agents, the identification of agents (their names, function, and addresses in the net), the way in and the way out of a gents of the society, the exchange of messages among agents and the search for agents with specific characteristics. First, a general view on Distributed Artificial Intelligence, the area in which this work is inserted, and some examples of agents are given. Next, the main characteristics of the Java language are introduced, since it is the language used in the implementations carried out. These implementations accomplished were prototypes which aim at gaining experience in the work with agents. All the programming of these a gents was carried out using the Java language, which was chosen for these implementations due to its characteristics. For example, the Java lan guage is Architecture Neutral, which in the case of programming for the Internet, becomes very desirable. After that, the main characteristics of two systems for the development of agents in the Internet, concerning their general architecture, were presented. These systems are SodaBot and Java Agent Template, the latter being totally implemented in the Java language. Finally, the architecture which was proposed is described in detail with an example of utilization and perspectives for a continuation of the work. The result obtained from this work is related to the proposal of an architecture which aims at making it possible to coordinate the interaction among agents which will be implemented in the Internet. The entire proposal was accompanied by studies of the feasibility of a future implementation of this architecture.
230

Geração de conjuntos de base para alguns átomos do 5º e 6º período da tabela periódica utilizando o método da coordenada geradora polinomial Hartree-Fock / Generation of basis sets for some atoms of the 5th and 6th periods of the periodic table using the Hartree-Fock Polynomial Generating Coordinate Method

Júlia Maria Aragon Alves 20 February 2017 (has links)
A equação de Schrödinger possui solução exata para átomos monoeletrônicos, porém devido ao nível de complexidade das soluções para átomos polieletrônicos e moléculas houve a necessidade de métodos aproximados que descrevessem satisfatoriamente as propriedades de interesse. O Método da Coordenada Geradora Hartree-Fock (MCG-HF) é um método variacional que permitiu desenvolver conjuntos de base acurados para átomos, entretanto, utilizando apenas a discretização integral, os conjuntos de base requeriam um maior número de expoentes, deixando-os extensos. Barbosa e da Silva (2009) introduziram o conceito de discretização integral polinomial que diminuiu a quantidade de expoentes necessários para descrever adequadamente um átomo, gerando conjuntos de base menores. Os conjuntos de primitivas gerados pelo p-MCG-HF foram contraídos utilizando o método de contração geral para a qualidade 5Z e em seguida, polarizados, utilizando dois métodos de polarização, ou seja, a pinçada e otimizada, para descrever melhor propriedades químicas como ligação química, estados excitados, entre outros. As energias obtidas por esses métodos de polarização são semelhantes, porém o tempo computacional é menor para a polarização pinçada (na maioria dos casos). Ao comparar os resultados obtidos neste trabalho com aqueles da literatura, os resultados obtidos utilizando o p-MCG-HF são de alta qualidade e com a enorme vantagem de ter tempo computacionais muito reduzidos. Esse método já está sendo aplicado por este grupo de pesquisa para gerar conjunto base para átomos do 1º ao 2º períodos da tabela periódica e os metais de transição e têm demonstrado resultados satisfatórios. Então, no intuito de estudar todos os átomos da tabela periódica até o bário, os átomos Gálio, Germânio, Arsênio, Selênio, Bromo, Criptônio, Rubídio, Estrôncio, Índio, Estanho, Antimônio, Telúrio, Iodo, Xenônio, Césio e Bário serão o foco deste trabalho. / The Schrödinger equation has exact solution for monoelectronic atoms, but the high complexity for the exact solution for many electron systems, lead to the use of approximation methods that satisfactorily. The Hartree-Fock Generating Coordinate Method (MCG-HF) is a variational method that allows the development of accurate basis sets for atoms with many electrons. However, using only an integral discretization, the basis sets generated with the MCG-HF requires a larger number of exponentes. Barbosa and da Silva (2009) introduced the concept of integral polynomial discretization that reduced the amount of exponents required to properly describe an atom, generating smaller basis sets. The sets of primitives generated with p-MCG-HF were contracted using the general contraction method for 5Z quality and then polarized using two different polarization methods (pinched and optimized) to better describe chemical properties such as chemical bonding, excited states, etc. The energies obtained with these polarization methods are similar, but the computational cost is smaller for pinched polarization (in most cases). Comparing the results obtained in this work with those of the literature, the results obtained by using the p-MCG-HF have a high quality and a large advantage of having very reduced computational cost. This method is already being applied in ours research group to generate basis set for atoms of the 1st to 2nd period of the periodic table and the transition metals showing satisfactory results. In order to study all the atoms in the periodic table, the atoms Gallium, Germanium, Arsenic, Selenium, Bromine, Crypton, Rubidium, Strontium, Indium, Tin, Antimony, Tellurium, Iodine, Xenium, Cesium and Barium will be focused in this work.

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