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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.
301

Modelling and verification of web services protocols.

Ramsokul, Pemadeep Kumar, Computer Science & Engineering, Faculty of Engineering, UNSW January 2008 (has links)
Among the plethora of solutions to the Business-to-Business interoperability problem, no other solution has obtained as much attention asWeb Services Technology (WST), which allows entities to exchange data regardless of their underlying platforms. WST also allows services to be composed in order to provide high quality customer service over the web. In order to perform transactions across different service providers, standard protocols need to be supported by participating providers. Many useful protocols are coming into the market, but are often ambiguously specified by protocol designers and not fully verified. Furthermore, even if the specifications are reasonably clear, programmers often make subtle assumptions, possibly leading to errors that are hard to detect and locate, especially when the number of participating entities is dynamic. Consequently, these can lead to interoperability problems among implementations of the same protocol and high software maintenance costs. To address these issues, a hierarchical automata-based framework is proposed to model the functional aspects of Web Services (WS) protocols that also assists in verifying their correctness. The modelling formalism has a sound mathematical foundation and aims to reconcile desirable features while still maintaining syntactic and semantic simplicity. The properties to be verified are specified using a pattern system and/or 'observer' states, which have been adapted for WS protocols. In particular, always in a positive observer state implies proper termination and partial functional correctness while reachability of a negative observer state signifies deadlock and/or violation of a safety property. Verification itself is handled by automatic translation of the model and its properties into a model-checker's input code and interpretation of the output produced by the model-checker. A test-bed is proposed to check the conformance of a protocol implementation to its specification It helps in locating errors in the implementations of WS protocols especially where the number of participating entities is dynamic. Conformance checking is achieved by capturing sequences of exchanged messages of the actual implementations and checking them against the formal specification. Experience using the framework is also described and illustrated using two non-trivial WS protocols, namely WS-BusinessActivity and WS-AtomicTransaction.
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302

Modelling and verification of web services protocols.

Ramsokul, Pemadeep Kumar, Computer Science & Engineering, Faculty of Engineering, UNSW January 2008 (has links)
Among the plethora of solutions to the Business-to-Business interoperability problem, no other solution has obtained as much attention asWeb Services Technology (WST), which allows entities to exchange data regardless of their underlying platforms. WST also allows services to be composed in order to provide high quality customer service over the web. In order to perform transactions across different service providers, standard protocols need to be supported by participating providers. Many useful protocols are coming into the market, but are often ambiguously specified by protocol designers and not fully verified. Furthermore, even if the specifications are reasonably clear, programmers often make subtle assumptions, possibly leading to errors that are hard to detect and locate, especially when the number of participating entities is dynamic. Consequently, these can lead to interoperability problems among implementations of the same protocol and high software maintenance costs. To address these issues, a hierarchical automata-based framework is proposed to model the functional aspects of Web Services (WS) protocols that also assists in verifying their correctness. The modelling formalism has a sound mathematical foundation and aims to reconcile desirable features while still maintaining syntactic and semantic simplicity. The properties to be verified are specified using a pattern system and/or 'observer' states, which have been adapted for WS protocols. In particular, always in a positive observer state implies proper termination and partial functional correctness while reachability of a negative observer state signifies deadlock and/or violation of a safety property. Verification itself is handled by automatic translation of the model and its properties into a model-checker's input code and interpretation of the output produced by the model-checker. A test-bed is proposed to check the conformance of a protocol implementation to its specification It helps in locating errors in the implementations of WS protocols especially where the number of participating entities is dynamic. Conformance checking is achieved by capturing sequences of exchanged messages of the actual implementations and checking them against the formal specification. Experience using the framework is also described and illustrated using two non-trivial WS protocols, namely WS-BusinessActivity and WS-AtomicTransaction.
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303

Network syslog monitor

Gummadi, Surender Reddy 01 January 2007 (has links)
The purpose of this project to develope a network syslog monitoring system to monitor network devices like printers, switches, etc. and to help the network technical help desk personnel to handle issues promptly and effectively based on the syslog messages captured by the syslog server.
304

Resource management in IP networks

Wahabi, Abdoul Rassaki 12 1900 (has links)
Thesis (MSc)--University of Stellenbosch, 2001. / ENGLISH ABSTRACT: lP networks offer scalability and flexibility for rapid deployment of value added lP services. However, with the increased demand and explosive growth of the Internet, carriers require a network infrastructure that is dependable, predictable, and offers consistent network performance. This thesis examines the functionality, performance and implementation aspects of the MPLS mechanisms to minimize the expected packet delay in MPLS networks. Optimal path selection and the assignment of bandwidth to those paths for minimizing the average packet delay are investigated. We present an efficient flow deviation algorithm (EFDA) which assigns a small amount of flow from a set of routes connecting each OD pair to the shortest path connecting the OD pair in the network. The flow is assigned in such a way that the network average packet delay is minimized. Bellman's algorithm is used to find the shortest routes between all OD pairs. The thesis studies the problem of determining the routes between an OD pair and assigning capacities to those routes. The EFDA algorithm iteratively determines the global minimum of the objective function. We also use the optimal flows to compute the optimal link capacities in both single and multirate networks. The algorithm has been applied to several examples and to different models of networks. The results are used to evaluate the performance of the EFDA algorithm and compare the optimal solutions obtained with different starting topologies and different techniques. They all fall within a close cost-performance range. They are all within the same range from the optimal solution as well. / AFRIKAANSE OPSOMMING: lP-netwerke voorsien die skaleerbaarheid en buigsaamheid vir die vinnige ontplooing van toegevoegde-waarde lP-dienste. Die vergrote aanvraag en eksplosiewe uitbreiding van die Internet benodig betroubare, voorspelbare en bestendige netwerkprestasie. Hierdie tesis ondersoek die funksionaliteit, prestasie en implementering van die MPLS(multiprotokoletiketskakel)- meganismes om die verwagte pakketvertraging te minimeer. Ons bespreek 'n doeltreffende algoritme vir vloei-afwyking (EFDA) wat 'n klein hoeveelheid vloei toewys uit die versameling van roetes wat elke OT(oorsprong-teiken)- paar verbind aan die kortste pad wat die OT-paar koppel. Die vloei word toegewys sodanig dat die netwerk se gemiddelde pakketvertraging geminimeer word. Bellman se algoritme word gebruik om die kortste roetes tussen alle OT-pare te bepaal. Die tesis bespreek die probleem van die bepaling van roetes tussen 'n OT-paar en die toewysing van kapasiteite aan sulke roetes. Die EFDA-algoritme bepaal die globale minimum iteratief. Ons gebruik ook optimale vloeie vir die berekening van die optimale skakelkapasiteite in beide enkel- en multikoers netwerke. Die algoritme is toegepas op verskeie voorbeelde en op verskillende netwerkmodelle. Die skakelkapasiteite word aangewend om die prestasie van die EFDAalgoritme te evalueer en dit te vergelyk met die optimale oplossings verkry met verskillende aanvangstopologieë en tegnieke. Die resultate val binne klein koste-prestasie perke wat ook na aan die optimale oplossing lê.
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305

Performance analysis and algorithm design for data-driven IP/ATM labelswitching systems

Zheng, Jun, 鄭軍 January 2000 (has links)
published_or_final_version / Electrical and Electronic Engineering / Doctoral / Doctor of Philosophy
306

iMAC : improved medium access control for multi-channel multi-hop wireless networks

Maiya, Megha 02 September 2010 (has links)
Trends in wireless networks are increasingly pointing towards a future with multi-hop networks deployed in multi-channel environments. In this thesis, we present the design for iMAC—a protocol targeted at medium access control in such environments. iMAC uses control packets on a common control channel to faciliate a three-way handshake between the sender and receiver for every packet transmission. This handshake enables the sender and receiver to come to consensus on a channel to use for data transmission and also signals to neighboring nodes about the contention on that channel. iMAC then uses a mechanism similar to 802.11 for data communication. Our evaluation of iMAC shows that it provides significant gains in throughput in comparison with uninformed channel selection, especially when contention for channel bandwidth is neither too low nor too high; intelligent selection of channels by iMAC is necessary to harness available bandwidth resources in the presence of medium levels of contention. / Graduation date: 2011
307

A SYSTEM ANALYSIS OF A MULTILEVEL SECURE LOCAL AREA NETWORK (COMPUTER).

Benbrook, Jimmie Glen, 1943- January 1986 (has links)
No description available.
308

SIP-based location service provision

Wu, YanHao January 2005 (has links)
Location-based service (LBS) is a geographical location-related service that provides highly personalized services for users. It is a platform for network operators to provide new and innovative ways of increasing profits from new services. With the rapidly growing trend toward LBS, there is a need for standard LBS protocols. This thesis started with introducing the Internet Engineering Task Force GEOPRIV working group, which endeavors to provide standard LBS protocols capable of transferring geographic location information for diverse location-aware applications. Through careful observation, it was found that Session Initiation Protocol (SIP) is well suited to the GEOPRIV requirements. The aim of this research was therefore to explore the possibility of the integration of LBS and the SIP protocol and, to some extent fulfill the GEOPRIV requirements.
309

SIP-based content development for wireless mobile devices with delay constraints.

Lakay, Elthea Trevolee January 2006 (has links)
<p>SIP is receiving much attention these days and it seems to be the most promising candidate as a signaling protocol for the current and future IP telephony services. Realizing this, there is the obvious need to provide a certain level of quality comparable to the traditional telephone service signalling system. Thus, we identified the major costs of SIP, which were found to be delay and security. This thesis discusses the costs of SIP, the solutions for the major costs, and the development of a low cost SIP application. The literature review of the components used to develop such a service is discussed, the networks in which the SIP is used are outlined, and some SIP applications and services previously designed are discussed. A simulation environment is then designed and implemented for the instant messaging service for wireless devices. This environment simulates the average delay in LAN and WLAN in different scenarios, to analyze in which scenario the system has the lowest costs and delay constraints.</p>
310

The resolution of domain name disputes : a comparison of Jordan, United Kingdom, United States, and ICANN rules

AbuGhazaleh, Shereen N. A. January 2010 (has links)
Domain names constitute a valuable key element in electronic commerce. However, some intend to benefit from this fact by registering identical or similar trademarks as domain names, thereby depriving the legitimate owners from obtaining the domain name. This thesis aims to evaluate the protection provided for domain names, by illustrating several models that are under civil, common and international jurisdiction, namely, Jordan, the United Kingdom, the United States and by ICANN. In the first model there are no special regulations. In the second model alternative regulations are applied while, in the third model, a special act is provided; the fourth model constitutes a global protection for specific types of domain name disputes. It is concluded that the absence of a unified legal identity for domain names is the reason why diverse positions are required to protect them; concomitantly, domain name disputes have not been sufficiently addressed, and there is a necessity to provide domain names with a globally comprehensive protection mechanism.

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