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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.
541

Likevekt i læring, læring i likevekt? : En studie av kjemisk likevekt i forhold til undervisning. / Equilibrium in learning, learning in equilibrium? : A study of chemical equilibrium in relation to teaching.

Brimi, Aslak Opsahl, Hansen, Mari Roen January 2008 (has links)
Kjemisk likevekt i forhold til undervisning er overordnet tema for denne masteroppgaven, og dette har vi sett på fra flere sider. Den første er fra et historisk perspektiv, inkludert temaets plass i eldre norske lærebøker. Så har vi sett på presentasjonen av kjemisk likevekt i nyere 2KJ-lærebøker i forhold til læring og forståelse. Til sist har vi studert forsøk, der hensikten med disse er å illustrere kjemisk likevekt. Kunnskapen om kjemisk likevekt kan kanskje sies å ha sitt utgangspunkt tidlig på 1700-tallet, i arbeidet med å forstå kjemiske reaksjoner. Det var affinitet som bestemte utfallet av reaksjoner (Geoffroys affinitetstabell, 1718). Først i andre halvdel av 1800-tallet skjøt utviklingen av temaet kjemisk likevekt for alvor fart, og det er i denne sammenhengen nordmennene Guldberg og Waage ofte nevnes, spesielt med deres første utkast til massevirkningsloven i 1864. Termodynamikken ble etter hvert mer framtredende etter 1850, og ut på 1900-tallet var affinitetsbegrepet stort sett borte. Gibbs fri energi hadde da tatt over som drivkraften i kjemiske reaksjoner. I dag mener mange at Guldberg og Waages utledning av massevirkningsloven, gjort med utgangspunkt i affinitetskrefter, er ufullstendig og at en termodynamisk begrunnelse må til. I de norske lærebøkene i kjemi har omfanget av, og dybden i forklaringen av kjemisk likevekt endret seg mye fra første gang det ble omtalt i Waages lærebok i 1908, til idag. Fram til krigens dager ble kjemisk likevekt stort sett kort forklart, gjerne sammen med massevirkningsloven. Etter 1940 ble det gitt en fyldigere forklaring i enkelte bøker, for eksempel ble forskyvning av likevektsposisjonen tatt med, men det er ikke noen entydig trend de neste tiårene. Mer fagstoff ble generelt presentert, med store variasjoner avhengig av forfatter. Først på 1970-tallet, hos Salveson og Wang Lund, ble temaet kjemisk likevekt belyst på nærmest samme måte som i dag. Le Châteliers prinsipp nevnes av få forfattere før 1950-tallet, men deretter presenteres det i de fleste av lærebøkene. Mange lærebokforfattere, helt fra begynnelsen av 1900-tallet, påpeker i forordene at kjemi må forståes ved forsøk, og dette tatt i betraktning er det overraskende få forsøk med kjemisk likevekt før fra 1970-tallet. Kjemisk likevekt er et svært vanskelig tema generelt, både for elever og lærere. Studier har vist at det for eksempel er problematisk å forstå reversibilitet, og å skille mellom reaksjonshastighet og likevektsposisjon, samt at et likevektsystem er dynamisk. Det er heller ikke enkelt å forutsi og forklare forskyvning av likevektsposisjonen. I følge R94 er kjemisk likevekt sentralt, noe som reflekteres i lærebøkene etter reformen. Lærebøkene har stort sett det samme fagstoffet med: En introduksjon med generell teori, noe om forskyvning av likevekt (bruk av Le Châteliers prinsipp) og litt om massevirkningsloven. Vi har sett at ikke alle lærebøkene er like konsekvente når det omtales hva som er i likevekt og hva dobbeltpilen står for. Sammen med at kjemisk likevekt er et vanskelig tema generelt, kan uklarheter i læreboktekster gjøre det ekstra problematisk. For å forutsi og forklare forskyvning av likevektsposisjonen blir Le Châteliers prinsipp nesten alltid brukt, selv om en slik bruk har blitt diskutert og kritisert i mange år. Flere forsøk med hensikt å illustrere kjemisk likevekt har blitt brukt, og brukes, i norsk kjemiundervisning. Disse viser reversibilitet og forskyvning av likevektsposisjonen, og kan derfor bidra til at elevene bedre forstår noe av det som er vanskelig med kjemisk likevekt.
542

Secure Mobile Authentication for Linux Workstation log on

Habib, Usman January 2010 (has links)
Password based logon schemes have many security weaknesses. For secure environments smart card and biometric based authentication solutions are available as replacement for standard password based systems. Nevertheless, the cost of deployment and maintenance of these systems is quite high. On the other hand, mobile network operators have a huge base of deployed smart cards that can be reused to provide authentication in other spheres significantly reducing costs. In this project we present a study of how mobile phones can be used to provide a secure low-cost two-factor workstation logon solution.To find and study the available mobile phone based authentication architectures and come up with workstation logon architecture the study of relevant technologies utilized in these solutions: UMTS networks, Bluetooth communication, Remote Authentication Dial in User Service (RADIUS), authentication and authorization in Windows, Linux, and MAC OS X. The analysis of available mobile phone based authentication schemes like SIM Strong schemes based on EAP-SIM, Session-ID based schemes, and OTP based schemes are also added.A solution for Linux workstation logon process has been proposed in the thesis using the Pluggable Authentication Module (PAM). The Solution uses 2 factors for authentication, one is the static password and the second factor is the mobile based authentication using a 13 character long OTP. With adding the existing technology and giving the administrator the option of selecting the authentication method for user makes the solution more suitable for an enterprise.
543

Service Discovery for Future Mobile Services

Bhatti, Atif, Choudhary, Imran Aslam January 2010 (has links)
The pervasive computing environment for heterogeneous network is on a continuous rise. The ability to interact and control network devices with different functionalities within office and home environment could be very beneficial to a lot of users. The service discovery in computers and mobile devices enabled them to interact with one another through wireless and heterogeneous wired networks. Services advertise their existence in a dynamic way and devices are designed with this capability to discover these services and its properties automatically. These devices are though based on different technologies but are still able to communicate and discover one another based on existing service discovery architectures. It is notable that a significant number of networked devices are now mobile and these mobile devices make service discovery more challenging.In future mobile multi-domain multi-language environments, a service can be anything and introduced by anybody. Consequently, same or equivalent services may have different names and services with same name or type may be completely different. Existing service discovery systems are incapable of handling these situations. We have implemented a service discovery system which supports semantics to service descriptions. It allows any user to act as a service provider and introduce any service at any time. The service provider can define any service as equivalent to any existing service and in any language as wanted. In addition, it is capable to find services that are not exact matches of the requested ones. More semantics are introduced through attributes like EquivalenceClass, ParentType and Keywords. The test conducted on this system in real time proves that the system is efficient and can be applied in real life.
544

Multi Protocol Label Switching – Transport Profile (MPLS-TP) in OpMiGua hybrid network

Katsavos, Christos January 2010 (has links)
This thesis presents the combination of MPLS-TP protocol with an integrated hybridnetwork, the Opmigua network. It is presented that the MPLS-TP protocol is applicableand follows all the requirements to be compatible with an Opmigua network. Differentnetwork scenarios, combining packet and circuit switching properties with MPLS-TPlabels, are presented. At the beginning of this thesis, are provided the characteristics and requirements of MPLS-TP protocol which the standardization of this is on going. Furthermore, it is explained how the MPLS-TP management and the forwarding plane work. Some references are also given not only to OAM mechanisms, but also to control plane that the MPLS-TP uses. We use both, global and local significance MPLS-TP labels for distinguishing theGuaranteed Service Traffic (GST) packets from Statistical Multiplexing (SM) packets.Using this method, we have concluded some results, as it concerns GST and SMtraffic. GST packets take a global significance label value until to reach the destination node. On the other hand, SM packets take local significance labels for each path into an Opmigua network which follow Optical Packet Switch (OPS) networks. We have proposed a new method for differentiation of packets from low to high priority using extension headers of Internet Protocol v6 either Destination Options Header(DOH) or MPLS-TP as an extension header. The result that we have derived is highand low priority packets are differentiated at ingress Opmigua network which GST packets take global significance MPLS-TP label following Optical Cross Connect (OXC) network and SM packets change per each Label Switched Path (LSP) local significance MPLS-TP labels until to reach the destination. Finally, two MPLS-TP path protection schemes, facility bypass and restoration usingdetours were combined with Opmigua network to provide failures for both, GuaranteedService Traffic (GST) packets and Statistical Multiplexing (SM) packets.
545

Autentisering og tilgangskontroll i system for eSporing / Authentication and Access Control in System for eSporing

Martinsen, Fredrik Folgerø January 2010 (has links)
eSporing er et prosjekt for å lage en nasjonal infrastruktur for elektronisk sporing i matkjeden. Denne infrastrukturen, betegnet som eSporingsløsningen, er basert på en tjenesteorientert arkitektur.Med tjenesteorienterte arkitekturer stilles det nye krav til sikkerheten da tradisjonelle mekanismer for sikkerhet ikke er gode nok. Oppgaven har sett på sikkerhetsaspekter i tjenesteorienterte arkitekturer, med fokus på autentisering og tilgangskontroll. En løsning, betegnet som en revidert arkitektur, er presentert som et av resultatene til oppgaven. Arkitekturen er utarbeidet fra en sikkerhetsanalyse på en konseptuell arkitektur. Den konseptuelle arkitekturen, med utgangspunkt i eSporing, innlemmer den funksjonalitet og oppbygning som er spesifikk for tjenesteorienterte arkitekturer. Med dette viser den reviderte arkitekturen til en måte å sikre nettverket og tjenester på som oppgaven har kommet fram til er den mest ideelle for gitt situasjon.Oppgaven har også sett på eSporingsløsningen og sammenlignet denne med den reviderte arkitekturen. Sammenligningen er det andre resultatet til oppgaven og er brukt til å vise til hvordan autentisering og tilgangskontroll kunne vært gjort annerledes i eSporingsløsningen.
546

Coordination Patterns for Reactive Services

Fatima, Urooj January 2010 (has links)
In our everyday life we come across countless reactive systems. These are the systems that engage in stimulus-response behaviour. The development of distributed reactive systems is quite complex. Being able to rapidly develop and incrementally deploy new services, while avoiding interactions with existing ones, is a challenging task. In this thesis, service examples of a distributed reactive system are modeled using the service engineering approach proposed by Humberto Nicolás Castejón in his PhD thesis; Collaborations in Service Engineering: Modeling, Analysis and Execution. First, services are modeled as collaborations between roles. Thereafter, the behaviour of each system component is designed as a composition of the roles it plays in the different services. In many cases, a component may be requested to participate simultaneously in several occurrences of the same service, or of different services (e.g. a UserAgent representing a user in a telecommunication system may be requested to participate in several phone calls simultaneously). To address such problems, extra coordination functionality is introduced in this thesis to coordinate the roles or role instances that a system component may play at a given point in time. For this, another role is defined, which is external to the service roles and serves to coordinate role binding. This role is named as ‘Controller’. The Controller is designed to keep track of the resource status, assign the resource if it is free, and if it is not then respond to the service invitation requests according to the preferences of the actors that receive them. Depending upon how the Controller performs the coordination functionality, some coordination patterns have been investigated. Apart from modeling the service from scratch and investigating the coordination patterns for it, it has been explored in this thesis how this coordination functionality can be added into an existing service model in a modular way. Some solutions are discussed but these are the initial thoughts which can be further explored in depth. The general structure of the coordination patterns has also been identified, which further strengthened the generality of the coordination patterns.
547

RFID implementation and performance analysis of a short MQQ digital signature

Soomro, Kamran Saleem January 2010 (has links)
Contactless smart cards (RFID cards) have been widely used for manyapplications such as epassport, ebanking, transit fare payment and accesscontrol systems. These cards have limited resources for performing arithmeticand logical operations and storing data along with program code. Asasymmetric cryptographic algorithms, performs time consuming complexoperations and demands more resources therefore these operations are performedin the special co-processors inside smart cards. The implementationof these extra co-processors increase the cost of smart cards.Recently a new algorithm Multivariate Quadratic Quasigroup (MQQ) hasbeen proposed for asymmetric cryptography and it is claimed that decryptionoprations are faster than already existing algorithms (RSA, ECC) [17].Eventually, a digital signature scheme based on MQQ has been proposedand it is named as MQQ-SIG [28]. In original MQQ public key algorithmthe size of private and public key was quite large in (KBytes). The size ofprivate key has been significantly reduced in MQQ-SIG scheme. Due tothis improvement in the private key size, it becomes possible to implementsigning procedure of MQQ-SIG inside contactless smart card. The fastsigning speed and simple operations performed in signing makes MQQSIGan appealing choice for smart cards which has constrained resourcescomparatively to other devices such as mobile cell phones and personalcomputers (PC).In this thesis we have implemented the digital signature part of MQQ-SIGalgorithm in Java for the 8-bit contactless smart card from the NXP familyJCOP 41 V2.2.1. These cards have Java Card Virtual Machine (JCVM)which enables limited features of Java. This is a completely original workand as far as we know there are no other Java implementations of MQQSIGdigital signature.Key generation part of MQQ is quite time consuming and therefore can notbe implemented inside smart cards. Similarly, verification part of MQQSIGutilize public key for verification of signed message. The public keyof MQQ scheme is quite large in hundreds of KBytes and therefore cannot be stored inside smart cards. These two parts of MQQ-SIG has beenimplemented on desktop computers and are not part of our Master thesis.
548

Cryptanalysis of IEEE 802.11i TKIP.

Lodhi, Ammar January 2010 (has links)
This thesis is based upon the work of Beck and Tews [ 24 ]. It presents and experimentally Validate the Beck and Tews attack on a network with QoS client Associated with a Non- QoS AP.This is done by Slightly extending the source code Provided by Beck and Tews . A detailed study of the wireless security protocols has Also Been done followed by description of how the original Beck and Tews attack works.Martin Beck define a new approach of obtaining keystreams [ 1 ] Which has Been Thoroughly analyzed . A description of how the different packets are exceptional in obtaining more usable keystreams has Been dealer. The experimental validation of how extra keystream bytes are Obtained through the new approach [ 1 ] has Been done . This was done Using one of the network security tools.
549

Furthering Educational Program Delivery through Master Gardener Speakers Bureaus

Fry, Jayla 2012 May 1900 (has links)
Although the demand for public presentations exists, barriers prevent many Master Gardener Volunteers from participating in speaking events. This study identifies the perspectives of both County Extension Agents and Master Gardener Volunteers on effective Master Gardener Speakers Bureaus. Characteristics and best practices of successful Speakers Bureaus are identified as well as barriers to their development and growth. A parallel mixed method study was designed to simultaneously gather qualitative and quantitative data. The results conclude for Master Gardener Speakers Bureaus to be successful, both agents and volunteers need to have a positive attitude and be support of the Speakers Bureau’s efforts. Utilizing volunteer leadership and offering training are the two best practices that emerged from the data and are recommended to overcome the barriers for Master Gardener Speakers Bureaus.
550

Undervisning av kjemisk binding som gir økt innsikt i stoffers oppbygning og egenskaper / Teaching of Chemical Bonds that Provides a Better Understanding of Structure, Composition and Properties of Substances

Brekke, Elisabeth Raknes January 2012 (has links)
Det overordnede temaet for denne masteroppgaven er undervisning av kjemiske bindinger, og da spesielt med tanke på elever i den videregående skolen. Temaet er likevel så generelt behandlet at prinsippene også kan overføres til andre undervisningstrinn. I oppgaven blir alternative oppfatninger av kjemiske bindinger sett i lys av forklaringsmodeller som kan gi elevene et forvrengt "kjemisk verdensbilde". Det er derfor viktig å benytte forklaringsmodeller som ikke blir til hinder for videre læring. I den sammenheng blir det foreslått her å legge mer vekt på elektrostatiske krefter. For at elevene skal få størst mulig læringsutbytte av emnet bør læreren videre utfordre elevene til å bruke informasjonen om kjemiske bindinger i møte med nye problemstillinger. I oppgaven blir det også lagt vekt på at stoffer kan tilnærmes via det makroskopiske, det molekylære og det elektriske nivået, og en viktig erkjennelse er at kjemiske bindinger bør belyse sider ved oppbygning og egenskaper knyttet til de konkrete stoffene vi kan erfare på det makroskopiske nivået - ikke motsatt. For at elevene skal utvikle forståelse av kjemiske bindinger er det viktig at disse tre nivåene som er nevnt over blir koblet sammen. Avslutningsvis blir det anbefalt å legge vekt på at alle kjemiske bindinger kan knyttes til elektrostatiske tiltreknings- og frastøtningskrefter. Det blir også lagt frem et forslag om å benytte partikkelmodellen mer aktivt, samt å legge mer vekt på fysiske egenskaper for å skape en sammenheng mellom det makroskopiske, det molekylære og det elektriske nivået.

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