Open-source cloud platforms provide a feasible alternative of deploying cloud computing in low-cost commodity hardware and operating systems. To enhance the reliability of an open-source cloud, we design and implement CloudVS, a practical add-on system that enables version control for virtual machines (VMs). CloudVS targets a commodity cloud platform that has limited available resources. It exploits content similarities across different VM versions using redundancy elimination (RE), such that only non-redundant data chunks of a VM version are transmitted over the network and kept in persistent storage. Using RE as a building block, we propose a suite of performance adaptation mechanisms that make CloudVS amenable to different commodity settings. Specifically, we propose a tunable mechanism to balance the storage and disk seek overheads, as well as various I/O optimization techniques to minimize the interferences to other co-resident processes. We further exploit a higher degree of content similarity by applying RE to multiple VM images simultaneously, and support the copy-on-write image format. Using real-world VM snapshots, we experiment CloudVS in an open-source cloud testbed built on Eucalyptus. We demonstrate how CloudVS can be parameterized to balance the performance trade-offs between version control and normal VM operations. / 開源雲端平台為供低成本硬件及作業系統提供一個可行的替代方案。為了提高開源雲的可靠性，我們設計及實踐了CloudVS，一個針對虛擬機的實用版本控制系統。CloudVS針對有限資源的低成本硬件雲平台，利用內容相似性，在不同的虛擬機版本使用冗餘消除。這樣，在虛擬機版本數據中只有非冗餘的部分在網絡上傳輸，並保存在持久存儲。使用冗餘消除作為構建塊，我們提出了一套性能適應機制，使CloudVS適合於不同的低成本硬件配置。具體而言，我們提出了一種可調諧的機制來平衡存儲和磁盤尋道開銷，以及應用各種I/O優化技術去最大限度地減少對其他同時運行進程的干擾。我們應用冗餘消除多個虛擬機影像去進一步利用其內容相似度，同時，我們更進一步支持寫時複製格式。使用來自真實世界的虛擬機快照，我們嘗試在開放源碼的雲測試平台Eucalyptus中測試CloudVS。我們演示CloudVS如何可以參數化，以平衡版本控制和正常的虛擬機操作之間的性能取捨。 / Tang, Chung Pan. / Thesis M.Phil. Chinese University of Hong Kong 2013. / Includes bibliographical references (leaves 57-65). / Abstracts also in Chinese. / Title from PDF title page (viewed on 07, October, 2016). / Detailed summary in vernacular field only.

Lai, Tsz Wai. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 193-207). / Abstracts in English and Chinese. / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Overview --- p.1 / Chapter 1.2 --- Contributions --- p.2 / Chapter 1.3 --- Organization --- p.2 / Chapter 2 --- Literature Review --- p.4 / Chapter 2.1 --- Taxonomy --- p.4 / Chapter 2.2 --- Design of Infrastructure --- p.6 / Chapter 2.2.1 --- Facility Location Models --- p.7 / Chapter 2.2.1.1 --- Random Breakdowns --- p.7 / Chapter 2.2.1.2 --- Deliberate Attacks --- p.8 / Chapter 2.2.2 --- Network Design Models --- p.9 / Chapter 2.3 --- Protection of Existing Components --- p.10 / Chapter 2.3.1 --- Interdiction Models --- p.11 / Chapter 2.3.2 --- Facility Location Models --- p.12 / Chapter 2.3.2.1 --- Random Breakdowns --- p.12 / Chapter 2.3.2.2 --- Deliberate Attacks --- p.12 / Chapter 2.3.3 --- Network Design Models --- p.14 / Chapter 3 --- Identifying Critical Facilities: Median Problem --- p.16 / Chapter 3.1 --- Introduction --- p.16 / Chapter 3.2 --- Problem Formulation --- p.18 / Chapter 3.2.1 --- The p-Median Problem --- p.18 / Chapter 3.2.1.1 --- A Toy Example --- p.19 / Chapter 3.2.1.2 --- Problem Definition --- p.21 / Chapter 3.2.1.3 --- Mathematical Model --- p.22 / Chapter 3.2.2 --- The r-Interdiction Median Problem --- p.24 / Chapter 3.2.2.1 --- The Toy Example --- p.24 / Chapter 3.2.2.2 --- Problem Definition --- p.27 / Chapter 3.2.2.3 --- Mathematical Model --- p.28 / Chapter 3.2.3 --- The r-Interdiction Median Problem with Fortification --- p.29 / Chapter 3.2.3.1 --- The Toy Example --- p.30 / Chapter 3.2.3.2 --- Problem Definition --- p.32 / Chapter 3.2.3.3 --- Mathematical Model --- p.33 / Chapter 3.2.4 --- The r-Interdiction Median Problem with Fortification (Bilevel Formulation) --- p.35 / Chapter 3.2.4.1 --- Mathematical Model --- p.36 / Chapter 3.3 --- Solution Methodologies --- p.38 / Chapter 3.3.1 --- Model Reduction --- p.38 / Chapter 3.3.2 --- Variable Consolidation --- p.40 / Chapter 3.3.3 --- Implicit Enumeration --- p.45 / Chapter 3.4 --- Results and Discussion --- p.48 / Chapter 3.4.1 --- Data Sets --- p.48 / Chapter 3.4.1.1 --- Swain --- p.48 / Chapter 3.4.1.2 --- London --- p.49 / Chapter 3.4.1.3 --- Alberta --- p.49 / Chapter 3.4.2 --- Computational Study --- p.50 / Chapter 3.4.2.1 --- The p-Median Problem --- p.50 / Chapter 3.4.2.2 --- The r-Interdiction Median Problem --- p.58 / Chapter 3.4.2.3 --- The r-Interdiction Median Problem with Fortification --- p.63 / Chapter 3.4.2.4 --- The r-Interdiction Median Problem with Fortification (Bilevel Formulation) --- p.68 / Chapter 3.5 --- Summary --- p.76 / Chapter 4 --- Hybrid Approaches --- p.79 / Chapter 4.1 --- Framework --- p.80 / Chapter 4.2 --- Tabu Assisted Heuristic Search --- p.81 / Chapter 4.2.1 --- A Tabu Assisted Heuristic Search Construct --- p.83 / Chapter 4.2.1.1 --- Search Space --- p.84 / Chapter 4.2.1.2 --- Initial Trial Solution --- p.85 / Chapter 4.2.1.3 --- Neighborhood Structure --- p.85 / Chapter 4.2.1.4 --- Local Search Procedure --- p.86 / Chapter 4.2.1.5 --- Form of Tabu Moves --- p.88 / Chapter 4.2.1.6 --- Addition of a Tabu Move --- p.88 / Chapter 4.2.1.7 --- Maximum Size of Tabu List --- p.89 / Chapter 4.2.1.8 --- Termination Criterion --- p.89 / Chapter 4.3 --- Hybrid Simulated Annealing Search --- p.90 / Chapter 4.3.1 --- A Hybrid Simulated Annealing Construct --- p.91 / Chapter 4.3.1.1 --- Random Selection of Immediate Neighbor --- p.92 / Chapter 4.3.1.2 --- Cooling Schedule --- p.93 / Chapter 4.3.1.3 --- Termination Criterion --- p.94 / Chapter 4.4 --- Hybrid Genetic Search Algorithm --- p.95 / Chapter 4.4.1 --- A Hybrid Genetic Search Construct --- p.99 / Chapter 4.4.1.1 --- Search Space --- p.99 / Chapter 4.4.1.2 --- Initial Population --- p.100 / Chapter 4.4.1.3 --- Selection --- p.104 / Chapter 4.4.1.4 --- Crossover --- p.105 / Chapter 4.4.1.5 --- Mutation --- p.106 / Chapter 4.4.1.6 --- New Population --- p.108 / Chapter 4.4.1.7 --- Termination Criterion --- p.109 / Chapter 4.5 --- Further Assessment --- p.109 / Chapter 4.6 --- Computational Study --- p.114 / Chapter 4.6.1 --- Parameter Selection --- p.115 / Chapter 4.6.1.1 --- Tabu Assisted Heuristic Search --- p.115 / Chapter 4.6.1.2 --- Hybrid Simulated Annealing Approach --- p.121 / Chapter 4.6.1.3 --- Hybrid Genetic Search Algorithm --- p.124 / Chapter 4.6.2 --- Expected Performance --- p.128 / Chapter 4.6.2.1 --- Tabu Assisted Heuristic Search --- p.128 / Chapter 4.6.2.2 --- Hybrid Simulated Annealing Approach --- p.138 / Chapter 4.6.2.3 --- Hybrid Genetic Search Algorithm --- p.146 / Chapter 4.6.2.4 --- Overall Comparison --- p.150 / Chapter 4.7 --- Summary --- p.153 / Chapter 5 --- A Special Case of the Median Problems --- p.156 / Chapter 5.1 --- Introduction --- p.157 / Chapter 5.2 --- Problem Formulation --- p.158 / Chapter 5.2.1 --- The r-Interdiction Covering Problem --- p.158 / Chapter 5.2.1.1 --- Problem Definition --- p.159 / Chapter 5.2.1.2 --- Mathematical Model --- p.160 / Chapter 5.2.2 --- The r-Interdiction Covering Problem with Fortification --- p.162 / Chapter 5.2.2.1 --- Problem Definition --- p.163 / Chapter 5.2.2.2 --- Mathematical Model --- p.164 / Chapter 5.2.3 --- The r-Interdiction Covering Problem with Fortification (Bilevel Formulation) --- p.167 / Chapter 5.2.3.1 --- Mathematical Model --- p.168 / Chapter 5.3 --- Theoretical Relationship --- p.170 / Chapter 5.4 --- Solution Methodologies --- p.172 / Chapter 5.5 --- Results and Discussion --- p.175 / Chapter 5.5.1 --- The r-Interdiction Covering Problem --- p.175 / Chapter 5.5.2 --- The r-Interdiction Covering Problem with Fortification --- p.178 / Chapter 5.5.3 --- The r-Interdiction Covering Problem with Fortification (Bilevel Formulation) --- p.182 / Chapter 5.6 --- Summary --- p.187 / Chapter 6 --- Conclusion --- p.189 / Chapter 6.1 --- Summary of Our Work --- p.189 / Chapter 6.2 --- Future Directions --- p.192

Det globala konsultföretaget CGI är leverantör för Sametingets nätverk. Behovet av en förbättrad övervakning på Sametingets nätverk efterfrågades av CGI. Genom att förnya och förbättra övervakningen säkerställs en snabbare felsökning och en högre tillgänglighet. Plattformen som skulle användas för att förverkliga målet heter CA Unified Infrastructure Management (CA UIM).   Eftersom slutprodukten skulle övervaka en skarp miljö så började arbetet med att upprätta en testmiljö där experiment kunde utföras. En liten del av arbetet bestod av att kartlägga det nätverk som skulle övervakas. Det huvudsakliga arbetet gick ut på att lära känna programvaran. UIM bygger på att prober utför insamling av data som sedan transporteras vidare till en gemensam databas för den specifika domänen. Databasen kan i sin tur leverera data till exempelvis dashboards på front-end sidan.  Följande prober har använts i vårt arbete: Net_Connect – Använder ICMP för att bekräfta en enhets tillgänglighet. Interface_Traffic - Övervakar nätverkstrafiken med SNMP-agenter. CDM - Ansvar för övervakningen av CPU, disk och minnesutnyttjande på servrar.   Efter att designen av våra dashboards var färdigställda och övervakningen fungerade så gick vi över till den skarpa miljön och upprättade samma koncept där. Arbetet presenteras sedan för CGI i Kiruna med positiva reaktioner.

Elasticsearch and Cassandra are two of the widely used databases today withElasticsearch showing a more recent resurgence due to its unique full text searchfeature, akin to that of a search engine, contrasting with the conventional querylanguage-based methods used to perform data searching and retrieval operations. The demand for more powerful and better performing yet more feature rich andflexible databases has ever been growing. This project attempts to study how the twodatabases perform under a specific workload of 2,000,000 fixed sized logs and underan environment where the two can be compared while maintaining the results of theexperiment meaningful for the production environment which they are intended for. A total of three benchmarks were carried, an Elasticsearch deployment using defaultconfiguration and two Cassandra deployments, a default configuration a long with amodified one which reflects a currently running configuration in production for thetask at hand. The benchmarks showed very interesting performance differences in terms of CPU,memory and disk space usage. Elasticsearch showed the best performance overallusing significantly less memory and disk space as well as CPU to some degree. However, the benchmarks were done in a very specific set of configurations and a veryspecific data set and workload. Those differences should be considered whencomparing the benchmark results.

The use of virtualized environments continues to grow for efficient utilization of the available compute resources. Hypervisors virtualize the underlying hardware resources and allow multiple Operating Systems to run simultaneously on the same infrastructure. Since the hypervisor is installed at a higher privilege level than the Operating Systems in the software stack it is vulnerable to rootkits that can modify the environment to gain control, crash the system and even steal sensitive information. Thus, runtime integrity measurement of the hypervisor is essential. The currently proposed solutions achieve the goal by relying either partially or entirely on the features of the hypervisor itself, causing them to lack stealth and leaving themselves vulnerable to attack. We have developed a performance sensitive methodology for identifying rootkits in hypervisors from System Management Mode (SMM) while using the features of SMI Transfer Monitor (STM). STM is a recent technology from Intel and it is a virtual machine manager at the firmware level. Our solution extends a research prototype called EPA-RIMM, developed by Delgado and Karavanic at Portland State University. Our solution extends the state of the art in that it stealthily performs measurements of hypervisor memory and critical data structures using firmware features, keeps performance perturbation to acceptable levels and leverages the security features provided by the STM. We describe our approach and include experimental results using a prototype we have developed for Xen hypervisor on Minnowboard Turbot, an open hardware platform.

This thesis develops and presents a design methodology that enables designers to work with the moving body in the design and evaluation of interactive, immersive environments built on motion-sensing technologies. The notion of making strange, that underpins the methodology, calls for designers to re-examine and revitalise their assumptions and conceptions of the moving body through bodily-based movement inquiries. This thesis addresses research questions about ways of understanding human movement, of describing and representing human movement and of accessing the felt experience of the moving body in the emerging field of movement-based interaction design. The research questions were explored through a series of three distinct, yet related, projects, each one focusing on different aspects of designing for moving bodies in interactive, immersive environments. The first project analysed an existing interactive product, Sony Playstation2c EyetoyTM, as a prototype of future movement-based interactive, immersive environments. The second project involved the design and development of a specific interactive, immersive artwork, Bystander. The third project worked with trained dancers and physical performers in a constructed design situation. The contributions of this research are first and foremost the design methodology of Moving and Making Strange: a design approach to movement-based interaction that prioritises the lived experience of movement by both designers and users and values the creative potential of the experiential, moving body. It consists of methods and tools for exploring, experiencing, describing, representing and generating movement that enable designers to shift between the multiple perspectives of the mover, the observer and the machine. It makes particular contributions as follows: • Laban movement analysis and Labanotation as a design tool. • Moving-Sensing schema: Suchman’s analytic framework adapted as a design tool. • Extension of existing human-centred design tools to explicitly represent moving bodies, in the form of movement-oriented personas and movementoriented scenarios. • Patterns of watching: a catalogue of audience behaviour in terms of movements and stillness in relation to engagement with a specific interactive, immersive artwork. • New methods for generating, enacting and experiencing movement, sourced from dance and movement improvisation practices.

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)

This thesis is concerned with temporal factors from the perspective of the interactive designer/interface designer and usability as a construct for guiding design activity. The research reported herein examines the many factors which emerge when considering the name of interaction at the user interface. Temporal Aspects of Usability (TAU) is presented as a multivariate construct. It is neither a property that exists 'in the head alone' not is it an aspect of the system but rather an emergent property arising from task based interactions. From a theoretical perspective, it is argued that the inclusion of temporal considerations to the task model more fully specifies 'Usability' as a design construct. A model of TAU is evolved and validated utilizing situated interviews with designers. This resulted in an Enhanced model of TAU. A method for developing temporally informed task models, KAT-LITTER (Leveraging Interactions Through Effective Responses), provides temporal design heuristics as the confluence of, KAT (Knowledge Analysis of Task) a task analysis method, and the enhanced TAU model. As a method, KAT-LITTER is device independent, data centered, domain specific and necessarily independent of existing implementations. A process evaluation of KAT-LITTER showed that it influenced the design process in two significant ways: firstly, designers using KAT-LITTER spent more time reasoning about temporal issues than designers using KAT alone, and secondly these same designers considered a broader spectrum of temporal issues. The development of TAU, its accompanying method, KAT-LITTER, complete with a notational system for analysis represent a significant step forward.

Batch processing is a means of improving the efficiency of transaction processing systems. Despite the maturity of this field, there is no rigorous theory that can assist in the design of batch systems. This thesis proposes such a theory, and shows that it is practical to use it to automate system design. This has important consequences; the main impediment to the wider use of batch systems is the high cost of their development and intenance. The theory is developed twice: informally, in a way that can be used by a systems analyst, and formally, as a result of which a computer program has been developed to prove the feasibility of automated design. Two important concepts are identified, which can aid in the decomposition of any system: 'separability', and 'independence'. Separability is the property that allows processes to be joined together by pipelines or similar topologies. Independence is the property that allows elements of a large set to be accessed and updated independently of one another. Traditional batch processing technology exploits independence when it uses sequential access in preference to random access. It is shown how the same property allows parallel access, resulting in speed gains limited only by the number of processors. This is a useful development that should assist in the design of very high throughput transaction processing systems. Systems are specified procedurally by describing an ideal system, which generates output and updates its internal state immediately following each input event. The derived systems have the same external behaviour as the ideal system except that their outputs and internal states lag those of the ideal system arbitrarily. Indeed, their state variables may have different delays, and the systems as whole may never be in consistent state. A 'state dependency graph' is derived from a static analysis of a specification. The reduced graph of its strongly-connected components defines a canonical process network from which all possible implementations of the system can be derived by composition. From these it is possible to choose the one that minimises any imposed cost function. Although, in general, choosing the optimum design proves to be an NP-complete problem, it is shown that heuristics can find it quickly in practical cases. / Thesis (Ph.D.)--Mathematical and Computer Sciences (Department of Computer Science), 1999.

This thesis develops and presents a design methodology that enables designers to work with the moving body in the design and evaluation of interactive, immersive environments built on motion-sensing technologies. The notion of making strange, that underpins the methodology, calls for designers to re-examine and revitalise their assumptions and conceptions of the moving body through bodily-based movement inquiries. This thesis addresses research questions about ways of understanding human movement, of describing and representing human movement and of accessing the felt experience of the moving body in the emerging field of movement-based interaction design. The research questions were explored through a series of three distinct, yet related, projects, each one focusing on different aspects of designing for moving bodies in interactive, immersive environments. The first project analysed an existing interactive product, Sony Playstation2c EyetoyTM, as a prototype of future movement-based interactive, immersive environments. The second project involved the design and development of a specific interactive, immersive artwork, Bystander. The third project worked with trained dancers and physical performers in a constructed design situation. The contributions of this research are first and foremost the design methodology of Moving and Making Strange: a design approach to movement-based interaction that prioritises the lived experience of movement by both designers and users and values the creative potential of the experiential, moving body. It consists of methods and tools for exploring, experiencing, describing, representing and generating movement that enable designers to shift between the multiple perspectives of the mover, the observer and the machine. It makes particular contributions as follows: • Laban movement analysis and Labanotation as a design tool. • Moving-Sensing schema: Suchman’s analytic framework adapted as a design tool. • Extension of existing human-centred design tools to explicitly represent moving bodies, in the form of movement-oriented personas and movementoriented scenarios. • Patterns of watching: a catalogue of audience behaviour in terms of movements and stillness in relation to engagement with a specific interactive, immersive artwork. • New methods for generating, enacting and experiencing movement, sourced from dance and movement improvisation practices.