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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.
1

Investigation of highly flexible, deployable structures : review, modelling, control, experiments and application

Friedman, Noémi 09 December 2011 (has links) (PDF)
In this thesis, an extensive review on different transformable systems used in architecture and civil engineering is given. After the review, structures undergoing large displacements and instability phenomenon were highlighted. The main goal of the dissertation was to investigate the general behavior of a specific, immature self-deploying system, the antiprismatic structure proposed by Hegedus. The emphasis was mainly taken to the analysis of the packing behavior. First, a simplified planar model was identified sharing similar, highly nonlinear packing behavior. For both the 2D and the 3D structures numerical simulation of the packing was performed with different type of controls and the results were confirmed by analytical investigations. The research clarifies the mechanical behavior of the chosen system, provides tools to simulate the packing of the structure, options for control, and gives very simple approximations for main mechanical characteristics of the antiprismatic system in order to facilitate preliminary design and verification of the numerical results. The significance of snap-back behavior, occurring at the force-displacement diagram during packing was analyzed. Within the framework of the thesis a novel type of system, slightly deviating from the original one was also investigated. For the specific systems, small physical models were built and presented in this work, which led to the proposal of a novel type of expandable tube. An attempt was given to provide ideas for application of antiprismatic structures by combining the investigated system and different learnt existing systems from the architectural review.
2

An analysis of the risk exposure of adopting IPV6 in enterprise networks

Berko, Istvan Sandor January 2015 (has links)
The IPv6 increased address pool presents changes in resource impact to the Enterprise that, if not adequately addressed, can change risks that are locally significant in IPv4 to risks that can impact the Enterprise in its entirety. The expected conclusion is that the IPv6 environment will impose significant changes in the Enterprise environment - which may negatively impact organisational security if the IPv6 nuances are not adequately addressed. This thesis reviews the risks related to the operation of enterprise networks with the introduction of IPv6. The global trends are discussed to provide insight and background to the IPv6 research space. Analysing the current state of readiness in enterprise networks, quantifies the value of developing this thesis. The base controls that should be deployed in enterprise networks to prevent the abuse of IPv6 through tunnelling and the protection of the enterprise access layer are discussed. A series of case studies are presented which identify and analyse the impact of certain changes in the IPv6 protocol on the enterprise networks. The case studies also identify mitigation techniques to reduce risk.
3

Investigation of highly flexible, deployable structures : review, modelling, control, experiments and application / Mécanique et application d'ingénieur des constructions élancées, notamment des structures déployables

Friedman, Noémi 09 December 2011 (has links)
Dans cette thèse, nous nous intéressons d’abord à de possibilités d’application des structures déployables en architecture et dans l’industrie de construction. Le thème principale de la recherche a été l’étude des structures subissant de grandes déformations et en passent par état d’instabilité au cours d’un programme de chargement. Le but était la description générale du comportement mécanique d’un système modèle d’une structure antiprismatique, auto-déployablée proposée par Hegedus. La plus grande importance a été mis sur exploitation du comportement de la structure au cours de son emballement, de qui a été examine en considérant différentes possibilités de contrôle de procédure. En utilisant des simulations numériques, dont les résultats ont été vérifiés par les approches analytiques, on a clarifié le comportement mécanique du système anti prismatique, et on a donné des formules simple permettant d’évaluer de principaux paramètres géométriques et mécaniques pour facilité le pré-dimensionnement de la structure. L’importance de l'influence de l’intensité et de la fréquence du déplacement relatif interne généré brusquement au cours d’emballement a été également étudiée. Dans le cadre de la thèse on a analysé également les caractéristiques mécaniques d’une système différent de la structure d’origine. Pour les deux différent systèmes structuraux on a préparé des modèles physiques expérimentaux, dont les résultat ont conduit aux nouveaux types des structures, lesquelles sont les structures spatiales pliables á plat. On a proposé alors quelques idées et schémas pour la possibilité d’application architecturale de systèmes treillis antiprismatiques. / In this thesis, an extensive review on different transformable systems used in architecture and civil engineering is given. After the review, structures undergoing large displacements and instability phenomenon were highlighted. The main goal of the dissertation was to investigate the general behavior of a specific, immature self-deploying system, the antiprismatic structure proposed by Hegedus. The emphasis was mainly taken to the analysis of the packing behavior. First, a simplified planar model was identified sharing similar, highly nonlinear packing behavior. For both the 2D and the 3D structures numerical simulation of the packing was performed with different type of controls and the results were confirmed by analytical investigations. The research clarifies the mechanical behavior of the chosen system, provides tools to simulate the packing of the structure, options for control, and gives very simple approximations for main mechanical characteristics of the antiprismatic system in order to facilitate preliminary design and verification of the numerical results. The significance of snap-back behavior, occurring at the force-displacement diagram during packing was analyzed. Within the framework of the thesis a novel type of system, slightly deviating from the original one was also investigated. For the specific systems, small physical models were built and presented in this work, which led to the proposal of a novel type of expandable tube. An attempt was given to provide ideas for application of antiprismatic structures by combining the investigated system and different learnt existing systems from the architectural review.
4

FairyBox:具個人化空間設置能力的桌上型智慧容器 / FairyBox: a customizable personal desktop container

廖云瑄, Liao, Yun-Hsuan Unknown Date (has links)
近年來隨著人口往都市集中,且高房價的時代來臨,導致生活空間更形狹小,而在狹小的生活空間中,桌子扮演了各式日常活動不可或缺的角色,不同種類、大小、高低的桌子輔助人們從事不同活動。其中,工作桌為使用情境最複雜的桌面環境,工作桌使用情境多卻又受限於狹小桌面環境,易導致工作空間不足、桌面堆滿許多物品。堆積雜亂的物品不但影響工作效率,在從事特定活動時看到不相干的物品,也會對使用者的情緒產生影響,干擾思緒。此外,放置在桌上的物品數量越多,重配置就越困難,所以無形中也限縮了使用者對桌面空間配置權。基於上述的觀察,本論文提出「FairyBox」桌上型智慧容器概念與原形實作,此裝置讓使用者將不同活動會用到的物品放在不同的容器中,從事特定活動時,配置相關物品的容器,並依照自己的喜好放置於桌面特定位置。這些容器將記得使用者所放置的位置,在往後從事該活動時,自動行進到桌面上的固定位置,類似桌面上的自走車。透過「FairyBox」,即使在狹小桌面從事多種活動,也可以避免影響情緒與專注力,並重拾對桌面的配置權,打造客製化的理想桌面空間。 / The workspace is one of the most complicated spaces in a living environment. One that works in a small workspace typically use a small table to handle tasks and activities. Thus, objects spread over the table in short time. Because objects arouse emotions, one’s thinking often interferes when a user observes many irrelevant objects spread on the table. Moreover, human creativity and efficiency are usually restricted because of the losing of the right of deploying things. This study aims to develop a device called “FairyBox,” which is a customizable personal desktop container. A user can put the objects into the FairyBox. Before a user is going to perform an activity, needing some objects previously placed in the FairyBox, the user just deploys FairyBox on the table wherever one wants. Then, when the activity is performed, the FairyBox goes to the deployed location autonomously. Using FairyBox, the user has more space when performing the activities in the workspace and thus is more focused on the activities.
5

Knowledge discovery using pattern taxonomy model in text mining

Wu, Sheng-Tang January 2007 (has links)
In the last decade, many data mining techniques have been proposed for fulfilling various knowledge discovery tasks in order to achieve the goal of retrieving useful information for users. Various types of patterns can then be generated using these techniques, such as sequential patterns, frequent itemsets, and closed and maximum patterns. However, how to effectively exploit the discovered patterns is still an open research issue, especially in the domain of text mining. Most of the text mining methods adopt the keyword-based approach to construct text representations which consist of single words or single terms, whereas other methods have tried to use phrases instead of keywords, based on the hypothesis that the information carried by a phrase is considered more than that by a single term. Nevertheless, these phrase-based methods did not yield significant improvements due to the fact that the patterns with high frequency (normally the shorter patterns) usually have a high value on exhaustivity but a low value on specificity, and thus the specific patterns encounter the low frequency problem. This thesis presents the research on the concept of developing an effective Pattern Taxonomy Model (PTM) to overcome the aforementioned problem by deploying discovered patterns into a hypothesis space. PTM is a pattern-based method which adopts the technique of sequential pattern mining and uses closed patterns as features in the representative. A PTM-based information filtering system is implemented and evaluated by a series of experiments on the latest version of the Reuters dataset, RCV1. The pattern evolution schemes are also proposed in this thesis with the attempt of utilising information from negative training examples to update the discovered knowledge. The results show that the PTM outperforms not only all up-to-date data mining-based methods, but also the traditional Rocchio and the state-of-the-art BM25 and Support Vector Machines (SVM) approaches.
6

Värdering av minor för mekaniserad strid / Assessment of landmines in mechanized battle

Bengtsson, Fred January 2021 (has links)
Stridsvagnsminans utveckling i helhet har under de senaste 20 åren mer eller mindre stått still. I försvarsberedningens slutrapport Värnkraft beskrivs fördröjande fältarbeten med minor som ett av de prioriterade områdena för Försvarsmaktens ingenjörförband. Med denna prioritering finns ett syfte att undersöka hur vidare minor fortsatt kommer att påverka den mekaniserade striden i framtiden.  För att studera minors påverkan på den mekaniserade striden har den här studien använt Totalförsvarets forskningsinstituts simuleringsverktyg Suss-mek. Minvapnet finns sedan tidigare inte implementerat i programmet. Därför undersöks också vilka nyckelegenskaper som bör ingå i simulering med minor i strid.  Resultatet visar att effekten av framtidens minor på den mekaniserade striden kommer i grunden vara densamma som idag. Däremot kommer teknologin för framtidens minor göra att minan i sig kommer att bli effektivare med högre sannolikhet att nedkämpa motståndaren. Studien kommer också fram till flera relevanta nyckelegenskaper, till exempel front, djup, densitet och fasta beteenden vid sammanstötminering. Det är egenskaper som måste tas hänsyn till vid modellering av minor i ett simuleringsverktyg. / The development of the antitank mine has more or less stood still for the past 20 years. In the Defense Committee's final report Värnkraft, counter-mobility operations with landmines is described as one of the priority areas for the Swedish Armed Forces' combat engineer units. With this priority, there is a purpose to investigate how mines will continue to affect the mechanized battle in the future.  To study the impact of antitank mines on the mechanized battle, this study has used the Swedish Defense Research Agency's simulation tool Suss-mek. The mine weapon has not previously been implemented in the program. Therefore, it is also investigated which key characteristics that should be included in simulation with mines in battle.  The results show that the impact of future antitank- mines in mechanized battle will basically be the same as today. On the other hand, the technology of the future mines will make the mine itself more efficient with a higher probability to kill. The study also shows several relevant key characteristics for example: front, depth, density and fixed behaviours during entering minefield. They are characteristics that must be considered when modelling mines in a simulation tool.

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