Operation of Unmanned Air Vehicles (UAVs) has increased significantly over the past few years. However, routine operation in non-segregated airspace remains a challenge, primarily due to nature of the environment and restrictions and challenges that accompany this. Currently, tight human control is envisaged as a means to achieve the oft quoted requirements of transparency , equivalence and safety. However, the problems of high cost of human operation, potential communication losses and operator remoteness remain as obstacles. One means of overcoming these obstacles is to devolve authority, from the ground controller to an on-board system able to understand its situation and make appropriate decisions when authorised. Such an on-board system is known as an Autonomous System. The nature of the autonomous system, how it should be designed, when and how authority should be transferred and in what context can they be allowed to control the vehicle are the general motivation for this study. To do this, the system must overcome the negative aspects of differentiators that exist between UASs and manned aircraft and introduce methods to achieve required increases in the levels of versatility, cost, safety and performance. The general thesis of this work is that the role and responsibility of an airborne autonomous system are sufficiently different from those of other conventionally controlled manned and unmanned systems to require a different architectural approach. Such a different architecture will also have additional requirements placed upon it in order to demonstrate acceptable levels of Transparency, Equivalence and Safety. The architecture for the system is developed from an analysis of the basic requirements and adapted from a consideration of other, suitable candidates for effective control of the vehicle under devolved authority. The best practices for airborne systems in general are identified and amalgamated with established principles and approaches of robotics and intelligent agents. From this, a decision architecture, capable of interacting with external human agencies such as the UAS Commander and Air Traffic Controllers, is proposed in detail. This architecture has been implemented and a number of further lessons can be drawn from this. In order to understand in detail the system safety requirements, an analysis of manned and unmanned aircraft accidents is made. Particular interest is given to the type of control moding of current unmanned aircraft in order to make a comparison, and prediction, with accidents likely to be caused by autonomously controlled vehicles. The effect of pilot remoteness on the accident rate is studied and a new classification of this remoteness is identified as a major contributor to accidents A preliminary Bayesian model for unmanned aircraft accidents is developed and results and predictions are made as an output of this model. From the accident analysis and modelling, strategies to improve UAS safety are identified. Detailed implementations within these strategies are analysed and a proposal for more advanced Human-Machine Interaction made. In particular, detailed analysis is given on exemplar scenarios that a UAS may encounter. These are: Sense and Avoid , Mission Management Failure, Take Off/Landing, and Lost Link procedures and Communications Failure. These analyses identify the nature of autonomous, as opposed to automatic, operation and clearly show the benefits to safety of autonomous air vehicle operation, with an identifiable decision architecture, and its relationship with the human controller. From the strategies and detailed analysis of the exemplar scenarios, proposals are made for the improvement of unmanned vehicle safety The incorporation of these proposals into the suggested decision architecture are accompanied by analysis of the levels of benefit that may be expected. These suggest that a level approaching that of conventional manned aircraft is achievable using currently available technologies but with substantial architectural design methodologies than currently fielded.

The first part of this work was to synthesise partially fluorinated reactive compounds and then to study their reactivity towards nucleophiles and electrophiles. These reactive compounds were obtained in a two step process from both cyclopentane and adamantane and in a three step process for cyclopentanol. The first step was the free radical addition of the cycloalkanes, cycloalcohol to hexafluoropropene via thermal and/or radiochemical alkylations. For the cyclic alkane derivatives, the second step was a stereospecific dehydrofluorination of the fluorocarbon chain, whereas for the cyclic alcohol, a dehydration and then dehydrofluorination were performed to give the conjugated diene. Finally, the fluoroalkene reactivity was studied via nucleophilic and electrophilic addition reactions. The second part of my work was to study the free radical addition of tertiary amines to hexafluoropropene, an example is illustrated below.

A method is proposed to infer stability properties for non-linear switching under continuous state feedback. Continuous-time systems which are dissipative in the multiple storage function sense are considered. A partition of the state space, induced by the cross-supply rates and the feedback function, is used to derive a restriction on switching. Then, conditions are proposed, under which, systems controlled by the feedback function and switching according to the rule are stable. In particular, Lyapunov and asymptotic stability are proved, both in a local and in a global context. Further, it is shown that the approach can be extended when one uses multiple controllers, and, therefore, is able to construct multiple partitions; conditions for this case are also presented. Finally, it is shown that, for the switching families that satisfy the switching rule posited by the results, one is able to find elements (that is, stabilising switching laws for the system) which are non-Zeno. Additional rule-sets that allow this are provided. It is argued that the conditions proposed here are easier to verify and apply, and that they offer additional flexibility when compared to those proposed by other approaches in the literature. The same infrastructure is used in the study of hybrid systems. For a general class of non-linear hybrid systems, a new property is proposed, that retains some of the properties of dissipativity, but it differs from it, crucially in the fact that it is not purely input-output. For systems having this property, it is shown that the partition used in the switching case can also be used. This, along with a set of conditions allows for the characterisation of the system behaviour in two scenaria. First, when the continuous behaviours and the jumping scheme act co-operatively, leading the system to lower energy levels (from the dissipativity point of view). Second, when the continuous behaviours are allowed to increase the stored energy, but the jumping is able to 6 compensate this increase. In the first case, it is shown that the equilibrium point under study is stable; in the second, it is shown that the system exhibits a type of attractivity, and, under additional conditions, it is asymptotically stable. Besides stability, a collection of stabilisation results are given for the case of dissipative switching systems. It is shown that one may design state feedback functions (controllers) with the objective that they satisfy the conditions of the stability theorems in this work. Then, systems under the designed controllers are shown to be stable, provided that the switching adheres to a specific switching rule. This problem is approached using a variety of tools taken from analysis, multi-valued functions and the space of non-switching stabilisation. In addition to the main results, an extensive overview of the literature in the area of switching and hybrid systems is offered, with emphasis on the topics of stability and dissipativity. Finally, a collection of numerical examples are given, validating the results presented here.

by Ching-Ting, Ng. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1996. / Includes bibliographical references (leaves 79-82). / Abstract --- p.i / Acknowledgement --- p.iii / Chapter 1 --- Introduction --- p.1 / Chapter 2 --- Background --- p.5 / Chapter 2.1 --- Protocols tackling site failure --- p.5 / Chapter 2.2 --- Protocols tackling Partition Failure --- p.6 / Chapter 2.2.1 --- Primary site --- p.6 / Chapter 2.2.2 --- Quorum Consensus Protocol --- p.7 / Chapter 2.2.3 --- Missing Writes --- p.10 / Chapter 2.2.4 --- Virtual Partition Protocol --- p.11 / Chapter 2.3 --- Protocols to enhance the Performance of Updating --- p.11 / Chapter 2.3.1 --- Independent Updates and Incremental Agreement in Replicated Databases --- p.12 / Chapter 2.3.2 --- A Transaction Replication Scheme for a Replicated Database with Node Autonomy --- p.13 / Chapter 3 --- Transaction Replication Scheme --- p.17 / Chapter 3.1 --- A TRS for a Replicated Database with Node Autonomy --- p.17 / Chapter 3.1.1 --- Example --- p.17 / Chapter 3.1.2 --- Problem --- p.18 / Chapter 3.1.3 --- Network Model --- p.18 / Chapter 3.1.4 --- Transaction and Data Model --- p.19 / Chapter 3.1.5 --- Histories and One-Copy Serializability --- p.20 / Chapter 3.1.6 --- Transaction Broadcasting Scheme --- p.21 / Chapter 3.1.7 --- Local Transactions --- p.22 / Chapter 3.1.8 --- Public Transactions --- p.23 / Chapter 3.1.9 --- A Conservative Timestamping Algorithm --- p.24 / Chapter 3.1.10 --- Decentralized Two-Phase Commit --- p.25 / Chapter 3.1.11 --- Partition Failures --- p.27 / Chapter 4 --- Simulation Model --- p.29 / Chapter 4.1 --- Simulation Model --- p.29 / Chapter 4.1.1 --- Model Design --- p.29 / Chapter 4.2 --- Implement at ion --- p.37 / Chapter 4.2.1 --- Simulation --- p.37 / Chapter 4.2.2 --- Simulation Language --- p.37 / Chapter 5 --- Performance Results and Analysis --- p.39 / Chapter 5.1 --- Simulation Results and Data Analysis --- p.39 / Chapter 5.1.1 --- Experiment 1 : Variation of TRS Period --- p.44 / Chapter 5.1.2 --- Experiment 2 : Variation of Clock Synchronization --- p.47 / Chapter 5.1.3 --- Experiment 3 : Variation of Ratio of Local to Public Transaction --- p.49 / Chapter 5.1.4 --- Experiment 4 : Variation of Number of Operations --- p.51 / Chapter 5.1.5 --- Experiment 5 : Variation of Message Transmit Delay --- p.55 / Chapter 5.1.6 --- Experiment 6 : Variation of the Interarrival Time of Transactions --- p.58 / Chapter 5.1.7 --- Experiment 7 : Variation of Operation CPU cost --- p.61 / Chapter 5.1.8 --- Experiment 8 : Variation of Disk I/O time --- p.64 / Chapter 5.1.9 --- Experiment 9 : Variation of Cache Hit Ratio --- p.66 / Chapter 5.1.10 --- Experiment 10 : Variation of Number of Data Access --- p.68 / Chapter 5.1.11 --- Experiment 11 : Variation of Read Operation Ratio --- p.70 / Chapter 5.1.12 --- Experiment 12 : Variation of One Site Failed --- p.72 / Chapter 5.1.13 --- Experiment 13 : Variation of Sites Available --- p.74 / Chapter 6 --- Conclusion --- p.77 / Bibliography --- p.79 / Chapter A --- Implementation --- p.83 / Chapter A.1 --- Assumptions of System Model --- p.83 / Chapter A.1.1 --- Program Description --- p.83 / Chapter A.1.2 --- TRS System --- p.85 / Chapter A. 1.3 --- Common Functional Modules for Majority Quorum and Tree Quo- rum Protocol --- p.88 / Chapter A.1.4 --- Majority Quorum Consensus Protocol --- p.90 / Chapter A. 1.5 --- Tree Quorum Protocol --- p.91

Systems-of-Systems (SoS) represent an emerging research field in the Software Engineering area. In particular, SoS refer to systems that make possible the interoperability of distributed, complex systems, cooperating among them to reach a common mission. Several SoS have already been developed and used, but there is no consensus about diverse terms and concepts in this field, what can make difficult the communication among different stakeholders involved in the development and evolution of SoS, besides lacking of a standardization and common understanding among researchers and practitioners. This Masters project established OntoSoS, an ontology to formalize terms and concepts in the SoS field, expliciting and allowing sharing and reuse of knowledge contained in such ontology. As a result, this project intends to contribute to the field of SoS, also supporting activities related to SoS Engineering. It is also expected that this ontology can serve as a learning material in courses related to SoS. / Sistemas-de-Sistemas (do inglês, Systems-of-Systems ou simplesmente SoS) representam um campo emergente de pesquisa na Engenharia de Software. Em particular, SoS referem-se a sistemas que possibilitam a interoperabilidade de sistemas complexos, distribuídos, cooperando entre si para atingir uma missão comum. Diversos SoS têm sido desenvolvidos e utilizados, mas não há um consenso sobre os diversos termos e conceitos nesse campo, o que pode dificultar a comunicação entre os diferentes interessados envolvidos no desenvolvimento e evolução dos SoS, além da falta de padronização e entendimento comum entre pesquisadores e profissionais. Este projeto de Mestrado estabeleceu a OntoSoS, uma ontologia para formalizar termos e conceitos no campo de SoS, explicitando e permitindo o compartilhamento e reúso do conhecimento contido na ontologia. Como resultado, este projeto pretende contribuir para o campo de SoS, auxiliando também nas atividades relacionadas à Engenharia de SoS. É também esperado que essa ontologia possa servir como um material de ensino em cursos relacionados à Engenharia de SoS.

Advances in wireless networking technology have engendered a new paradigm of computing, called mobile computing; in which users carrying portable devices have access to a shared infrastructure independent of their physical location. Mobile computing has matured rapidly as a field of computer science. In environments of mobile computing, the mobility and disconnection of portable computing devices introduce many new challenging problems that have never been encountered in conventional computer networks. New research issues combine different areas of computer science: networking, operating systems, data and knowledge management, and databases. This thesis studies data and knowledge transaction in mobile environments. To study transaction processing at the fundamental and theoretical level in mobile environments, a range of classical notions and protocols of transaction processing are rechecked and redefined in this thesis, and form the foundation for studying transaction processing in mobile environments. A criterion for mobile serial history is given and two new concurrency theorems are proved in mobile environments. In addition to data transaction, this thesis explores knowledge transaction in mobile environments. To study knowledge transaction in mobile environments this thesis presents and formalizes a knowledge transaction language and model for use in mobile computing environments. The thesis further formalizes a framework/model for a mobile logic programming multi-agent system which can be used to study knowledge transaction in multi-agent systems in mobile environments and is a very early effort towards a formal study of knowledge base and intelligent agents in mobile environments. This work provides a foundation for the formal specification and development of real-world mobile software systems, in the same way as traditional software systems have developed. / Doctor of Philosophy (PhD) (Science)

Thesis (MSc)--University of Stellenbosch, 2006. / Bibliography. Also available via the Internet.

Thesis (M.A. in Security Studies (Homeland Security and Defense))--Naval Postgraduate School, December 2009. / Thesis Advisor(s): Bergin, Richard. Second Reader: Munks, Jeffrey. "December 2009." Description based on title screen as viewed on January 27, 2010. Author(s) subject terms: Interoperable communications; multi-discipline, multi-jurisdictional radio communications; risk and governance; shared governance; policy and consensus teams, Monterey Police Department. Includes bibliographical references (p. 71-73). Also available in print.

Thesis (Ph. D.)--School of Electrical and Computer Engineering, Georgia Institute of Technology, 2004. Directed by D. Scott Wills. / Vita. Includes bibliographical references (leaves 105-111).

Thesis (Ph. D.)--University of Hong Kong, 2001. / Includes bibliographical references (leaves 187-198).