• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 276
  • 248
  • Tagged with
  • 524
  • 427
  • 362
  • 121
  • 80
  • 78
  • 66
  • 51
  • 48
  • 48
  • 40
  • 38
  • 32
  • 29
  • 29
  • 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.
61

Searching and Classifying non-textual information

Arentz, Will Archer January 2004 (has links)
This dissertation contains a set of contributions that deal with search or classification of non-textual information. Each contribution can be considered a solution to a specific problem, in an attempt to map out a common ground. The problems cover a wide range of research fields, including search in music, classifying digitally sampled music, visualization and navigation in search results, and classifying images and Internet sites. On classification of digitally sample music, as method for extracting the rhythmic tempo was disclosed. The method proved to work on a large variety of music types with a constant audible rhythm. Furthermore, this rhythmic properties showed to be useful in classifying songs into music groups or genre. On search in music, a technique is presented that is based on rhythm and pitch correlation between the notes in a query theme and the notes in a set of songs. The scheme is based on a dynamic programming algorithm which attempts to minimize the error between a query theme and a song. This operation includes finding the best alignment, taking into account skipped notes and additional notes, use of different keys, tempo variations, and variances in pitch and time information. On image classification, a system for classifying whole Internet sites based on the image content, was proposed. The system was composed of two parts; an image classifier and a site classifier. The image classifier was based on skin detection, object segmentation, and shape, texture and color feature extraction with a training scheme that used genetic algorithms. The image classification method was able to classify images with an accuracy of 90%. By classifying multi-image Internet web sites this accuracy was drastically increased using the assumption that a site only contains one type of images. This assumption can be defended for most cases. On search result visualization and navigation, a system was developed involving the use of a state-of-the-art search engine together with a graphical front end to improve the user experience associated with search in unstructured data. Both structured and unstructured data with the help of entity extraction can be indexed in a modern search engine. Combining this with a multidimensional visualization based on heatmaps with navigation capabilities showed to improve the data value and search experience on current search systems. / Paper III reprinted with kind permission of Elsevier Publishing, sciencedirect.com.
62

Study of security aspects for Session Initiation Protocol / Analys av säkerheten kring Session Initiation Protocol

Kullenwall, Jonas January 2002 (has links)
The objective with this thesis is to describe security mechanisms that are inte-grated or are proposed to be integrated with the Session Initiation Protocol (SIP). SIP is used for establishing, modifying, and terminating multimedia ses-sions over the IP network. This thesis is divided into two main parts, where the first part describes the implemented security mechanisms in SIP and the second part describes a number of proposed security mechanisms that may be implemented in SIP. At the end of the report there is a section that presents the scripts and results from different security tests that were performed on two implementations of SIP. Apart from describing different security mechanisms in the first part of this thesis, this section also contains an analysis on how possible security threats against SIP may be used to launch different attacks. The analysis also describes how these attacks may be prevented, if possible, by using the secu-rity mechanisms provided by SIP. The second part also contains an analysis section, which is focusing on finding the advantages and disadvantages of using a specific security mechanism compared to a similar security mechanism that is currently used or has been used in SIP. In the last section of this thesis I present my conclusions and a summary of the results.
63

Säkerhet i Wireless Local Area Networks : En studie i säkerhetslösningar utförd på uppdrag av Saab Bofors Dynamics AB. / Security in Wireless Local Area Networks

Thorn, Evelina January 2004 (has links)
Saab Bofors Dynamics AB is looking for ways to let the employees work wireless in the future. The security in Wireless Local Area Networks (WLAN) has not been considered very reliable, but new standards and protocols have been developed to enhance the security in WLAN. Since most wireless components soon will have built in support for wireless communication, it is important to have a model to deal with secure wireless communication ready. This is necessary because it is important to protect the company’s information related systems, ensure contingency in the daily work and maintaining the trust of the market and the authorities. With the release of the standard IEEE802.11i, the possibility to build a secure WLAN has improved considerably. With the combination of standards such as IEEE802.1X and IEEE802.11i, and improved encryption with Advanced Encryption Standard (AES) it is possible to make the wireless network more secure. It is important to ensure secure wireless communication between the client and the accesspoint, and to install a personal firewall on every wireless client in the network. There are many aspects to take into consideration when building a WLAN, some are discussed in this report and some are discussed in the secret part of the report for Saab Bofors Dynamics AB only.
64

Contingency planning for Bofors Defence AB, an application of existing methods / Upprättande av avbrottsplaner för Bofors Defence AB, ett tillämpningsexempel

Karlsson, Terése January 2002 (has links)
Bofors Defence AB is in the process of updating and documenting the company’s routines for information security. The object is to be certified according to the standard ISO 17799-1 during 2003. Among other things updating means that the company will be provided with contingency plans who should insure a reliable IT-environment. Basically it is all about protecting the company’s information related systems, ensure contingency in the daily work and maintaining the trust of the market and the authorities. The aim of the Thesis was to apply existing methods in the making of contingency plans. The plans are focused on the information related systems that are critical to the company and takes in consideration the threats, which might stop them from operating as desired. The contingency plans cover a limited numberof systems, which for example handle e-mail and order intake. The plans comprise the servers and platforms (for example operating systems), which are essential to the systems. The Thesis is focused on the aspect of availability. The aspects of confidentiality (for example fire walls) and integrity (for example access restrictions) are handled by the company’s own personnel. To ensure contingency is only a minor part of the work that needs to bee done before a company can be certified according to ISO 7799-1. This Thesis needs complementary additions before it can be incorporated in the documentation presented to the accreditation agency. However the result is in line with the company’s commission.
65

Heuristisk detektering av trojaner / Heuristic Detection of Trojans

Mischel, Magnus January 2005 (has links)
The heuristic methods used by the anti-trojan application TrojanHunter have been evaluated. The evaluation shows that the heuristic scan engine of TrojanHunter has a very good detection ratio and that the detection ratio can be even further improved by implementing the suggested improvements, the most important of which is a white list to avoid misidentifying files that are known not to be trojans.
66

On access network selection models and mobility support in heterogeneous wireless networks

Andersson, Karl January 2010 (has links)
The aim of this thesis is to define a solution offering end-users seamless mobility in a multi-radio access technology environment. Today an increasing portion of cell phones and PDAs have more than one radio access technology and wireless access networks of various types are commonly available with overlapping coverage. This creates a heterogeneous network environment in which mobile devices can use several networks in parallel. In such environment the device needs to select the best network for each application to use available networks wisely. Selecting the best network for individual applications constitutes a major core problem.The thesis proposes a host-based solution for access network selection in heterogeneous wireless networking environments. Host-based solutions use only information available in mobile devices and are independent of information available in the networks to which these devices are attached. The host-based decision mechanism proposed in this thesis takes a number of constraints into account including network characteristics and mobility patterns in terms of movement speed of the user. The thesis also proposes a solution for network-based mobility management contrasting the other proposals using a host-based approach. Finally, this thesis proposes an architecture supporting mobility for roaming users in heterogeneous environments avoiding the need for scanning the medium when performing vertical handovers.Results include reduced handover latencies achieved by allowing hosts to use multihoming, bandwidth savings on the wireless interface by removing the tunneling overhead, and handover guidance through the usage of directory-based solutions instead of scanning the medium. User-perceived quality of voice calls measured on the MOS (Mean Opinion Score) scale shows no or very little impact from the mobility support procedures proposed in this thesis. Results also include simulation models, real-world prototypes, and testbeds that all could be used in future work. The proposed solutions in this thesis are mainly evaluated using simulations and experiments with prototypes in live testbeds. Analytical methods are used to complement some results from simulations and experiments / Godkänd; 2010; 20100811 (karand); DISPUTATION Ämnesområde: Mobila system/Mobile Systems Opponent: Universitetslektor, docent Marcus Fiedler, Blekinge tekniska högskola Ordförande: Universitetslektor, docent Christer Åhlund, Luleå tekniska universitet Tid: Fredag den 12 november 2010, kl 11.00 Plats: A1514 Demostudion, Luleå tekniska universitet
67

Lärares användning av "IKT" i undervisningen

Jacobsen Andersson, Janet, Johansson, Marita January 2006 (has links)
<p>Bakgrund:1973 inleddes ett stort arbete med att få in datorer i skolmiljön. Genom åren har olika projekt genomförts och idag handlar det om att lärarna skall ledaskolutveckling med stöd av regionala nätverk. Den nuvarande läroplanen, Lpo 94 lägger stor vikt vid att elever skall kunna orientera sig i en komplex verklighet, medett stort informationsflöde och en snabb förändringstakt. Vidare går att läsa i läroplanen att varje elev också skall kunna använda informationsteknik som ettverktyg för sitt eget lärande. Piagets och Vygotskijs utvecklingspsykologiska teori är att kunskap inte kan tillhandahållas av läraren utan att kunskap måste konstrueras av den som lär.</p><p>Under elevens egen lärandeprocess är det viktigt att eleven har en lärare som handleder. På samma sätt som andra alternativa pedagogiker, metoder ochverktyg erbjuder ”IKT” olika möjligheter att bidra till elevens lärande.</p><p>Syfte:Uppsatsen syftar till att ta reda på om lärare använder IKT i undervisningen och i så fall omfattningen.</p><p>Metod:Vi har gjort en enkät med slutna och öppna svarsalternativ vilka skickades ut till lärare i en västsvensk medelstor stad. Svaren bearbetades såväl kvantitativt somkvalitativt. Resultatet av undersökningen redovisas i löpande text och med citat inlagda för att illustrera och belägga våra tolkningar.</p><p>Resultat:I vår undersökning visar resultatet att det är de äldre, mer erfarna lärarna som har någon form av datautbildning. Resultatet visar också att de äldre lärarna med mererfarenhet använder IKT i undervisningen oftare och i fler situationer än de yngre lärarna med mindre erfarenhet.</p>
68

IT-användandet i distribuerade projekt

Johansson, Jenny, Nielsen, Maria, Persson, Martin January 2002 (has links)
No description available.
69

IT i skolan : en studie av hur datorer används i skolan

Niotis, Dimitrios January 2007 (has links)
<p>SAMMANFATTNING</p><p>Syfte och frågeställningar</p><p>Syftet med denna uppsats är att ta reda på hur datorerna som finns i skolan används.</p><p>* Kan man se några tydliga skillnader mellan en innerstadsskola och en förortsskola?</p><p>* Hur ser elevernas datavanor ut?</p><p>Metod</p><p>Min uppsats är en kvantitativ studie. För att besvara mina frågeställningar har jag använt mig av en enkät. Enkäten som jag har gjort är till stora delar hämtad från examensarbetet Datorer i skolan som skrevs på Idrottshögskolan för 10 år sedan. Jag tyckte att många av deras frågor var intressanta och fortfarande aktuella.</p><p>Resultat</p><p>Svaren från enkäten visade att datorn används mest i ämnen som matematik, svenska och engelska i förortsskolan medan i innerstadsskolan har man använt datorn i svenska, engelska och bild. I innerstaden använder man ofta datorn till att hämta information från Internet och göra presentationer i t.ex. PowerPoint. Förortseleverna använder också datorn till att hämta information från Internet. En annan skillnad mellan de två skolorna är att man i förorten låter eleverna i högre grad använda datorn även till annat än skolarbete medan det sällan händer i innerstaden.</p><p>Det fanns många fler likheter än olikheter mellan skolorna. Alla barnen i båda skolorna tyckte om att arbeta med datorer vilket inte är så förvånande i dessa tider då datorerna har blivit så vanliga.</p><p>Slutsats</p><p>Datorn har blivit en naturlig del i elevernas sökning efter information. Datorn används också mycket till att jobba med skolans kärnämnen som t.ex. matematik, svenska och engelska vilket är bra för den ökade måluppfyllelsen som det ofta pratas om i dagens skola. Mycket hänger dock på lärarens datautbildning och inställning till att integrera datorn i undervisningen.</p> / Grundskollärarutbildningen 1999-2003
70

Lärares användning av "IKT" i undervisningen

Jacobsen Andersson, Janet, Johansson, Marita January 2006 (has links)
Bakgrund:1973 inleddes ett stort arbete med att få in datorer i skolmiljön. Genom åren har olika projekt genomförts och idag handlar det om att lärarna skall ledaskolutveckling med stöd av regionala nätverk. Den nuvarande läroplanen, Lpo 94 lägger stor vikt vid att elever skall kunna orientera sig i en komplex verklighet, medett stort informationsflöde och en snabb förändringstakt. Vidare går att läsa i läroplanen att varje elev också skall kunna använda informationsteknik som ettverktyg för sitt eget lärande. Piagets och Vygotskijs utvecklingspsykologiska teori är att kunskap inte kan tillhandahållas av läraren utan att kunskap måste konstrueras av den som lär. Under elevens egen lärandeprocess är det viktigt att eleven har en lärare som handleder. På samma sätt som andra alternativa pedagogiker, metoder ochverktyg erbjuder ”IKT” olika möjligheter att bidra till elevens lärande. Syfte:Uppsatsen syftar till att ta reda på om lärare använder IKT i undervisningen och i så fall omfattningen. Metod:Vi har gjort en enkät med slutna och öppna svarsalternativ vilka skickades ut till lärare i en västsvensk medelstor stad. Svaren bearbetades såväl kvantitativt somkvalitativt. Resultatet av undersökningen redovisas i löpande text och med citat inlagda för att illustrera och belägga våra tolkningar. Resultat:I vår undersökning visar resultatet att det är de äldre, mer erfarna lärarna som har någon form av datautbildning. Resultatet visar också att de äldre lärarna med mererfarenhet använder IKT i undervisningen oftare och i fler situationer än de yngre lärarna med mindre erfarenhet.

Page generated in 0.112 seconds