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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.
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Showing 661 to 670 of 671 (0.067 seconds)Spelling suggestions: "subject:"defined"" "subject:"efined""
| 661 |
Renforcement de la sécurité à travers les réseaux programmablesAbou El Houda, Zakaria 09 1900 (has links)
La conception originale d’Internet n’a pas pris en compte les aspects de sécurité du réseau; l’objectif prioritaire était de faciliter le processus de communication. Par conséquent, de nombreux protocoles de l’infrastructure Internet exposent un ensemble de vulnérabilités. Ces dernières peuvent être exploitées par les attaquants afin de mener un ensemble
d’attaques. Les attaques par déni de service distribué (Distributed Denial of Service ou DDoS) représentent une grande menace et l’une des attaques les plus dévastatrices causant des dommages collatéraux aux opérateurs de réseau ainsi qu’aux fournisseurs de services Internet.
Les réseaux programmables, dits Software-Defined Networking (SDN), ont émergé comme
un nouveau paradigme promettant de résoudre les limitations de l’architecture réseau actuelle
en découplant le plan de contrôle du plan de données. D’une part, cette séparation permet
un meilleur contrôle du réseau et apporte de nouvelles capacités pour mitiger les attaques
par déni de service distribué. D’autre part, cette séparation introduit de nouveaux défis en
matière de sécurité du plan de contrôle.
L’enjeu de cette thèse est double. D’une part, étudier et explorer l’apport de SDN
à la sécurité afin de concevoir des solutions efficaces qui vont mitiger plusieurs vecteurs
d’attaques. D’autre part, protéger SDN contre ces attaques. À travers ce travail de
recherche, nous contribuons à la mitigation des attaques par déni de service distribué sur
deux niveaux (intra-domaine et inter-domaine), et nous contribuons au renforcement de
l’aspect sécurité dans les réseaux programmables. / The original design of Internet did not take into consideration security aspects of the
network; the priority was to facilitate the process of communication. Therefore, many of the
protocols that are part of the Internet infrastructure expose a set of vulnerabilities that can
be exploited by attackers to carry out a set of attacks. Distributed Denial-of-Service (DDoS)
represents a big threat and one of the most devastating and destructive attacks plaguing
network operators and Internet service providers (ISPs) in a stealthy way.
Software defined networks (SDN), an emerging technology, promise to solve the limitations
of the conventional network architecture by decoupling the control plane from the data
plane. On one hand, the separation of the control plane from the data plane allows for more
control over the network and brings new capabilities to deal with DDoS attacks. On the
other hand, this separation introduces new challenges regarding the security of the control
plane.
This thesis aims to deal with various types of attacks including DDoS attacks while
protecting the resources of the control plane. In this thesis, we contribute to the mitigation
of both intra-domain and inter-domain DDoS attacks, and to the reinforcement of security
aspects in SDN.
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| 662 |
EFFECT OF FLOW PARAMETERS OF WATER AND AIR ATOMIZED SPRAYS ON COOLING INTENSITY OF HOT SURFACES / EFFECT OF FLOW PARAMETERS OF WATER AND AIR ATOMIZED SPRAYS ON COOLING INTENSITY OF HOT SURFACESBoháček, Jan January 2011 (has links)
Práce komplexně popisuje vodní a vodovzdušné chlazení pomocí metod CFD (Computational Fluid Dynamics) konkrétně s využitím software ANSYS FLUENT. Skládá se ze dvou hlavních částí, z nichž první se zabývá numerickým popisem jediné vodní kapky a druhá popisem směsí kapek představující paprsek válcové a ploché trysky. Je založena převážně na vícefázových modelech proudění a vlastních uživatelsky definovaných funkcí (User Defined Functions, UDF) představujících stěžejní část práce. Uvedené výpočtové modely jsou ve většině případů verifikovány pomocí experimentálních dat nebo jiných numerických modelů. V první části práce jsou teoreticky postupně rozebrány všechny tři použité vícefázové modely proudění. První z nich, Volume Of Fluid model (VOF), byl použit pro modelování jediné kapky (mikromodel). Zatímco zbývající dva, Euler-Euler model a Euler-Lagrange model, byly aplikovány v modelu celého paprsku trysky (makromodel). Mikromodel popisuje dynamiku volného pádu vodní kapky. Pro malé průměry kapek (~100µm) standardní model povrchového napětí (Continuum Surface Force, CSF) způsoboval tzv. parazitní proudy. Z toho důvodu je v práci rozebrána problematika výpočtu normál, křivostí volných povrchů a povrchového napětí jako zdroje objemových sil v pohybových rovnicích. Makromodel se zabývá studiem dynamiky celého paprsku tj. oblastí od ústí trysky po dopad na horký povrch, bere v úvahu kompletní geometrii, tzn. např. podpůrné válečky, bramu, spodní část krystalizátoru apod. V práci je rozebrána 2D simulace dopadu paprsku válcové trysky pomocí VOF modelu Euler-Lagrange modelu na horký povrch. Pro případ s VOF modelem byl navržen model blánového varu. Euler-Euler model a Euler-Lagrange model byly využity pro simulaci paprsku ploché trysky horizontálně ostřikující horkou bramu přímo pod krystalizátorem nad první řadou válečků. Pro Euler-Euler model byl navržen model sekundárního rozpadu paprsku založený na teorii nejstabilnější vlnové délky (Blob jet model). Jelikož diskrétní Lagrangeovy částice tvořily v určitých místech spíše kontinuální fázi, byl navržen a otestován model pro konverzi těchto částic do VOF.
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| 663 |
Automatic Modulation Classifier - A Blind Feature-Based ToolCutno, Patrick 29 November 2016 (has links)
No description available.
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| 664 |
[en] COGNITIVE RADIO PERFORMANCE WITH COOPERATIVE SPECTRUM SENSING / [pt] DESEMPENHO DE REDES DE RÁDIO COGNITIVO COM SENSORIAMENTO COOPERATIVO DO ESPECTROJUSSIF JUNIOR ABULARACH ARNEZ 18 May 2020 (has links)
[pt] Nesta tese de doutorado foi investigado, por meio de simulações computacionais e em laboratório utilizando Matlab, GNU Radio e GNU Radio Companion (GRC), o desempenho de redes de Rádio Cognitivo com sensoriamento individual (SS) e com sensoriamento cooperativo (CSS) do espectro considerando o algoritmo não paramétrico de detecção de energia e diferentes abordagens deste método de detecção. Foi também implementado um cenário de medição em tempo real usando os equipamentos de rádio definido por software (SDR por suas siglas em inglês) conhecidos como Universal Software Radio Peripheral (USRP).
Os cenários de medição consideram a cooperação, baseada na utilização de regras de fusão de dados do tipo hard, no sensoriamento local de sinais de TV Digital por usuários cognitivos não licenciados.
A principal contribuição desta tese de doutorado baseia-se na formulação do método de energia combinando os conceitos da teoria clássica do sensoriamento de espectro das redes de Rádio Cognitivo, tanto com sensoriamento individual (SS) como sensoriamento cooperativo (CSS) de espectro, com um cenário de implementação em laboratório levando em conta os requisitos, parâmetros técnicos e de operação do equipamento de medição SDR. / [en] This PhD thesis investigate the performance of cognitive radio networks with single sensing (SS) and cooperative spectrum sensing (CSS) networks through computational and laboratory simulations using Matlab, GNU Radio and the GNU Radio Companion (GRC) computational radio software, considering the
non-parametric energy detection method and different approaches to this method.
The implementation also includes a real-time measurement testbed scenario using Software Defined Radio (SDR) equipment, known as Universal Software Radio Peripheral (USRP). The measurement scenarios consider the cooperative local sensing of the digital TV by non-licensed cognitive radio users, based on hard
fusion rules.
The main contribution of this doctoral thesis is based on the formulation of the energy detection method combining the concepts of the classical theory of the spectrum sensing of Cognitive Radio networks, with both individual sensing (SS) and cooperative spectrum sensing (CSS), in a laboratory implementation scenario according to the requirements, technical parameters and operation of the SDR measuring equipment.
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| 665 |
員工持股計畫中受任人義務之研究 / A study of fiduciary duty under employee stock ownership plan李松諺 Unknown Date (has links)
員工持股計畫是由財經律師Louis Kelso所創，在美國已行之多年，廣為美國企業所採。最早的員工持股計畫是一種為了和平地從資本家手中移轉資本給員工、縮減貧富差距的工具。為了使這個計畫可以持續有效地運作下去，立法者將員工持股計畫為退休金計畫的一種，使員工必須長期持有股票，直到退休。然而在實務運作上，員工持股信託經常被運用為防止敵意併購的工具。尤有甚者，某些公司內部人會利用員工持股計畫為自己取得大量資金、移轉投資風險,但仍可保留對於公司的控制力。這些行為都有可能對股東及員工造成不利的影響，但在現行法制下，只能仰賴司法者透過判決保護這些經濟及資訊上的弱勢族群。
在台灣，員工持股計畫雖然已廣為許多企業所採用，但是發展了將近20年，只能成為另一種員工持有股票的工具。員工擁有的股票數量並不足以使其在股東會上贏得一個受公司內部人重視的地位，也不足以倚賴這些股票作為退休金之用。這種規模上的差異是台美員工持股計畫最關鍵的不同點。小規模雖然使員工持股計畫帶來的優勢少了許多，但相對地也減低許多代理成本，至今未有員工持股計畫侵害大量員工利益的事件爆發。然而這不表示員工持股計畫在台灣就是個可以被忽略的問題，若能在未來建立一套有效率的立法制度，使員工持股計畫的規模擴大，員工將可因此享受到更多公司盈餘，並且使其退休生活受到保障。相對地，參考美國員工持股計畫的問題後，也可以預先設想未來可能發生的弊端，未雨綢繆。本文相信，一個有效率的員工持股計畫，可以實現解決貧富不均的理想。 / Employee stock ownership plan (ESOP) which is created by Louis Kelso is brought to practice for many years. Many enterprises use it as their retirement pension plan. The earliest employee stock ownership plan to transfer the capital frome capitalists to labors and reduce the disparity between the rich and the poor.In order to make the plan work out continueously and effectively, the legislator devise ESOP as a pension fund which makes employee own stock chronically until they retires. However, in practice, ESOP is usually exercised for preventing hostile takeover. Moreover, some company insiders may use ESOP TTO get a great deal of capital and transfer the investment risk, but still own the controlling power to their company. This behaviors will cause some harmful effects to the shareholders and the employees, but in the current legal system,the only one we can depend is the judge who can protect the minority in the economic and the information.
ESOP is exercised by many enterprises in Taiwan. But after 20 years, it can only become one of the tools which assist employees to acquire company stocks.The number of shares which employees owns can’t make them have a posi-tion which let the company insiders take account in the shareholder committee and have enough amounts for their retirement pensions.This disparity in scale is the keypoint what is different between Tiwan and the U.S. ESOP. Althoygh small scale makes the adventage of ESOP decrease, it reduce lots of agency costs. To this day, there’re not any events which injure the interests of employees by ESOP. Never-theless, it doesn’t mean that ESOP in Taiwan is a issue which can be neglected. If we can establish an efficient legal system and extend the scale of ESOP, employees can obtain more company interests and have a security of their retirement life.In the opposite, after researching the problem of the U.S. ESOP, we can assume the culpably misconduct which will happen in the future and repair the house before it rains。Ｉ believe that a efficient ESOP can realize the ideal to solve the problem of uneven distribution of the wealth.
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| 666 |
The role of the lecturer in cultivating a relationship of trust with the student teacher with special reference to teaching practice in the former Transkei regionMsengana, Enid Ntombizolundi 11 1900 (has links)
This study deals with the problem relating to the prevalence of a lack of
trust amongst members of today's society generally, and in particular
between college lecturers and student teachers.
The aim of the dissertation is to investigate the role of the lecturer in
cultivating a relationship of trust with the student teacher, especially
during teaching practice. The study reveals that the trust relationship
manifests itself in various moments. Some characteristics of an effective
supervising lecturer are also reflected upon.
The major research consists of an empirical investigation into which
characteristics of an effective supervising lecturer contribute most towards
cultivating a relationship of trust with student teachers during teaching
practice. A survey of colleges of education and schools in the former
Transkei region participating in the empirical investigation is also
conducted.
The findings of the research indicate that the following categories need
to be enhanced 'through training : personal, professional and guidance. / Education / M. Ed. (Philosophy of Education)
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| 667 |
The role of the lecturer in cultivating a relationship of trust with the student teacher with special reference to teaching practice in the former Transkei regionMsengana, Enid Ntombizolundi 11 1900 (has links)
This study deals with the problem relating to the prevalence of a lack of
trust amongst members of today's society generally, and in particular
between college lecturers and student teachers.
The aim of the dissertation is to investigate the role of the lecturer in
cultivating a relationship of trust with the student teacher, especially
during teaching practice. The study reveals that the trust relationship
manifests itself in various moments. Some characteristics of an effective
supervising lecturer are also reflected upon.
The major research consists of an empirical investigation into which
characteristics of an effective supervising lecturer contribute most towards
cultivating a relationship of trust with student teachers during teaching
practice. A survey of colleges of education and schools in the former
Transkei region participating in the empirical investigation is also
conducted.
The findings of the research indicate that the following categories need
to be enhanced 'through training : personal, professional and guidance. / Education / M. Ed. (Philosophy of Education)
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| 668 |
Three Essays on the Consequences of TransparencyWitter, Tobias 01 September 2023 (has links)
This dissertation comprises three essays which empirically investigate consequences of transparency. The first essay investigates how transparency, demanded by the government as a customer of firms, affects firms’ financial reporting. It provides evidence that, relative to firms without government customers, government suppliers have a higher quality of financial reporting. Findings indicate that government procurement requirements, which are linked to internal control over financial reporting, can positively affect the external information environment of firms. The second essay examines how managers react to a stricter transparency mandate in pension accounting, if this mandate increases the expected volatility of balance sheet items. Managers of affected firms change decisions on pension plans which mitigate volatility and in addition, affected firms exhibit less volatile accruals but more volatile discretionary real actions suggesting managers reduce volatility in balance sheets. Findings imply that a transparency mandate in pension accounting may have (unintended) consequences for managerial decision-making if the mandate reveals more economic volatility on balance sheets. The third essay studies how (data-transparently) researchers visualize their quantitative findings and how this affects the impact of academic work. It finds that, compared to articles in field-specific economics journals, articles in economics journals with a broader audience use more figures than tables and that articles visualizing (data-transparently) with figures receive more citations. An online experiment, which manipulates how a fictive study visualizes scientific results, finds that participants assess the internal validity of research as being higher and are more willing to cite research if it visualizes results data-transparently. The findings imply that (data-transparent) visualization can enhance the impact of academic work. / Die Dissertation besteht aus drei Aufsätzen, die die Auswirkungen von Transparenz untersuchen. Im ersten Aufsatz wird analysiert, wie sich die von einer Regierung im Rahmen der öffentlichen Auftragsvergabe geforderte Unternehmenstransparenz auf die Finanzberichterstattung von Unternehmen auswirkt. Lieferanten der Regierung weisen eine höhere Qualität der Finanzberichterstattung auf als Vergleichsunternehmen. Der zweite Aufsatz untersucht, wie Manager auf strengere Transparenzanforderungen in der Pensionsbilanzierung reagieren, wenn diese die Bilanzvolatilität erhöhen. Die Manager nehmen Bilanzanpassungen vor, die die Volatilität reduzieren, was auf eine beabsichtigte Bilanzglättung hindeutet. Der dritte Aufsatz untersucht den Zusammenhang zwischen der Visualisierung von quantitativen Forschungsergebnissen in wirtschaftswissenschaftlichen Zeitschriften und dem Einfluss akademischer Forschung. Economics-Journals verwenden mehr Abbildungen als Business-Journals, was Zitationen zu fördern scheint. Experimentelle Evidenz zeigt weiterhin, dass datentransparente Visualisierungen den Einfluss akademischer Forschung positiv beeinflussen können, dass dies aber auch stark disziplinabhängig ist.
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| 669 |
The legalisation and regulation of online gambling in South AfricaMorgan, Kirsty Kate January 2017 (has links)
Magister Legum - LLM (Mercantile and Labour Law)
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| 670 |
Snižování hluku kolejových vozidel v traťových obloucích / Reduction of noise of the railway vehicles in line arcsNavrátil, Václav January 2019 (has links)
reducing noise, noise in railway transport, management of application of products for modification of adhesion
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