Hiermit versichere ich, die vorliegende Diplomarbeit selbstständig und unter ausschliesslicher Verwendung der angegebenen Quellen und Hilfsmittel angefertigt zu haben. Diese Arbeit hat in gleicher oder ähnlicher Form noch keiner Prüfungsbehörde vorgelegen. Darmstadt, 14. Februar 2006

aimed at enabling secure access to services astride organizational boundaries. Also, Kerberos has continued to evolve as new functionalities are added to the basic protocol and one of well-known these protocols is PKINIT. First, I review and analyze the structure of Kerberos recently proposed

I declare that this thesis is my own account of my research and contains as its main content work which has not previously been submitted for a degree at any tertiary education institution.

This thesis presents CraneTracker, a multi-modal sensing and communication system for monitoring migratory species at the continental level. By exploiting the robust and extensive cellular infrastructure across the continent, traditional mobile wireless sensor networks can be extended to enable reliable, low-cost monitoring of migratory species. The developed multi-tier architecture yields ecologists with unconventional behavior in-formation not furnished by alternative tracking systems at such a large scale and for a low-cost. The simulation, development and implementation of the CraneTracker soft-ware system is presented. The system is shown effective through multiple proxy deploy-

applications, developing software for these types of networks is extremely dffcult, preventing their wide-spread use. Three primary challenges are (1) the high level of dynamics within the network in terms of changing wireless links and node hardware con gurations, (2) the wide variety of hardware present

This Open Access Dissertation is brought to you for free and open access by the Dissertations and Theses at ScholarWorks@UMass Amherst. It has

1. Networking trends 2. QoS over data networks 3. Label switching 4. Gigabit, 10 Gb Ethernet, RPR 5. Storage area networks 6. IP over DWDM 7. Wireless 8. Voice over IP

April 29, 2011Für UnsShe had never before seen a rabbit with either a waistcoat-pocket, or a watch to take out of it, and burning with curiosity, she ran across the field after it Lewis CarrollThe following document, written under the supervision of Dr. reviewed by:

Abstract not found

Messaging is a basic service in sensornets. Yet the unique system and application prop-erties of sensornets pose substantial challenges for the messaging design: Firstly, dynamic wireless links, constrained resources, and application diversity challenge the architecture and protocol design of sensornet messaging; Secondly, complex faults and large system scale introduce new challenges to the design of fault-tolerant protocols. The objective of this dissertation is to address the aforementioned challenges of sensornet messaging. Despite the extensive effort in studying sensornet messaging, the lack of a basic un-derstanding of its essential components has been an obstacle for reliable, efcient, and reusable messaging services in sensornets. To address this problem, one task of this dis-sertation is to identify the basic components of sensornet messaging and to study the re-lated algorithmic design issues. More specically, we propose the messaging architecture SMA that consists of three components: trafc-adaptive link estimation and routing (TLR), application-adaptive structuring (AST), and application-adaptive scheduling (ASC). TLR deals with dynamic wireless links as well as the impact of application trafc patterns on