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The need for a continuous supply of electric power is vital to providing the basic services of modern life. The energy infrastructure that the vast majority of the world depends on, while very reliable, is also very vulnerable. This infrastructure is particularly vulnerable to disruptions caused by natural disasters. Interruptions of electric service can bring an end to virtually all the basic services that people are dependent on. Recent natural disasters have highlighted the vulnerabilities of large, economically developed, regions to disruptions to their supply of electricity. The widespread devastation from the 2011 Japanese Tsunami and Hurricane Irene in North America, have demonstrated both the vulnerability of the contemporary power grids to long term interruption of service and also the potential of microgrids to ride through these interruptions. Microgrids can be used before, during, and after a major natural disaster to supply electricity, after the main grid source has been interrupted. This thesis researches the potential of clean energy microgrids for disaster recovery. Also a model of a proposed residential microgrid for transient analysis is developed. As the world demands more energy at increasingly higher levels of reliability, the role of microgrids is expected to grow aggressively to meet these new requirements. This thesis will look at one potential application for a microgrid in a residential community for the purpose of operating in an independent island mode operation. / Master of Science

Advances in technology have led to fully integrated operator consoles which offer a broad range of solutions. Industry's move towards networking has resulted in the operator consoles being located at critical sites throughout the plant-floor. However, a lot of programming effort is required in order to use these consoles effectively. <p>The project addressed the problem by developing a software interface for the future user in a distributed automation environment. The system developed is capable of operating on IBM industrial computers, connected through a communications network on a DAE environment. By using the functions provided, the future user is insulated from the lower level control sequences of the operator interface and need only be concerned about the operation of these functions. <p>A description of the development of each phase project is given, and the purpose and operation subroutines are also presented in this report. / Master of Science

Although the Task Team on leadership and development (DoE, 1996) has introduced the notion of shared (collaborative) leadership as embodied among others in school management teams, considerable doubt remains about its practical implementation (DoE, 1996). It seems that there may be widespread failure to implement the idea of collaborative (shared) leadership (DoE, 1996). The problem this research explores is whether, in the opinion of school management team members, the traditional approach to leadership has changed (DoE, 1996). According to Grant (2006 in Grant&Singh, 2009), despite an enabling democratic policy framework the leadership at many South African schools seems to remain firmly entrenched within the formal, hierarchical management structure. During the period of colonialism and apartheid in South Africa government legislation perpetuated a society of inequality based on race, class and gender (Grant 2006 in Grant & Singh, 2009). To control and maintain this inequality, government policies promoted centralised, authoritarian control of education at all levels within the system (Grant 2006 in Grant&Singh, 2009). Today, within a democratic South Africa, the South African Schools Act (1996), the Government Gazette of the Norms and Standards for Educators (2000) and the Task Team Report on Education Management Development (DoE, 1996) challenge schools to review their management policies, which have traditionally been top-down, and create a whole new approach to managing schools where management is seen as an activity in which all members of education engage and should not be seen as the task of a few (DoE, 1996:27). According to Moloi (2002 in Grant&Singh, 2009), although our education policies call for new ways of managing schools, many remain unresponsive and retain their rigid structures because educators are unable to make a shift away from patriarchal ways of thinking. It is against this backdrop that I explore whether leadership has indeed shifted to become more participatory and inclusive. One form of leadership that would reflect this shift is termed collaborative leadership (Grant&Singh, 2009). This form of leadership is based on the premise that leadership should be shared throughout an organisation such as a school (Grant&Singh, 2009). This alternate form of leadership allows for the emergence of teachers as one of the multiple sources of guidance and direction (Grant&Singh, 2009). According to Grant and Singh (2009), collaborative leadership offers a radical departure from the traditional understanding of leadership because it deconstructs the notion of leadership in relation to position in the school. It constructs leadership as a process which involves working with all stakeholders in a collegial and creative way to seek out the untapped leadership potential of people and develop this potential in a supportive environment for the betterment of the school (Grant&Singh, 2009). The general aim of this research is to investigate school management teams’ understanding of the implementation of collaborative leadership in primary schools in Gauteng District 4 in Pretoria. In this research I discuss important issues relating to collaborative leadership. My findings reveal that schools management teams indeed understand and implement collaborative leadership in their schools but also that collaborative leadership is much more than just working together as a team. My argument is that there must be a radical reconceptualisation of the concept of collaborative leadership as well as an attempt to move towards more dispersed and democratic forms of it. / Dissertation (MEd)--University of Pretoria, 2012. / Education Management and Policy Studies / unrestricted

<div>In recent years, the amount of data in the information processing systems has significantly increased, which is also referred to as big-data. The design of systems handling big-data calls for a scalable approach, which brings distributed systems into the picture. In contrast to centralized systems, data are spread across the network of agents in the distributed system, and agents cooperatively complete tasks through local communications and local computations. However, the design and analysis of distributed systems, in which no central coordinators with complete information are present, are challenging tasks. In order to support communication among agents to enable multi-agent coordination among others, practical communication constraints should be taken into consideration in the design and analysis of such systems. The focus of this dissertation is to provide design and analysis of distributed network processing using finite-rate communications among agents. In particular, we address the following open questions: 1) can one design algorithms balancing a graph weight matrix using finite-rate and simplex communications among agents? 2) can one design algorithms computing the average of agents’ states using finite-rate and simplex communications? and 3) going beyond of ad-hoc algorithmic designs, can one design a black-box mechanism transforming a general class of algorithms with unquantized communication to their finite-bit quantized counterparts?</div><div><br></div><div>This dissertation addresses the above questions. First, we propose novel distributed algorithms solving the weight-balancing and average consensus problems using only finite-rate simplex communications among agents, compliant to the directed nature of the network topology. A novel convergence analysis is put forth, based on a new metric inspired by the</div><div>positional system representations. In the second half of this dissertation, distributed optimization subject to quantized communications is studied. Specifically, we consider a general class of linearly convergent distributed algorithms cast as fixed-point iterate, and propose a novel black-box quantization mechanism. In the proposed mechanism, a novel quantizer preserving linear convergence is proposed, which is proved to be more communication efficient than state-of-the-art quantization mechanisms. Extensive numerical results validate our theoretical findings.</div>

Uno de los compromisos que tiene el Estado Peruano es dotar a la población de los medios necesarios para preservar su salud; uno de estos medios es proporcionar la medicina necesaria a través de sus instituciones y organizaciones públicas de salud. Sin embargo, en el Perú, el 60% de los medicamentos que requiere la población, la cual se atienden en las instituciones de salud pública, son adquiridos en las farmacias privadas, esta situación es debido a una falencia en los procesos de adquisición de medicamentos, pues estos principalmente se focalizan en el movimiento de stock de las farmacias públicas y no en la necesidad real de medicamentos, en adición, estos procesos son inadecuados y no cuentas con soporte tecnológico. El presente trabajo, tiene como objetivos el desarrollar una propuesta de salud que proponga un proceso y herramientas tecnológicas que promueva la colaboración entre toda la red de salud dedicada a la adquisición de medicamentos, así como dotar de una herramienta tecnológica que no solo se centre en el stock de las farmacias, sino también, en la prescripción de la medicina y la morbilidad de cada rincón del país. Así mismo, la solución contempla una arquitectura tecnológica al alcance del Estado Peruano, con redundancia, alta disponibilidad y escalabilidad. Es importante destacar que la solución propuesta, se ha elaborado siguiendo enfoques de arquitectura empresarial, donde se prima los objetivos organizacionales, así como técnicas y métodos vigentes de arquitectura empresarial que permiten un fácil entendimiento y su posterior implementación. / One of the commitments that the Peruvian State has is to provide the population with the necessary means to preserve their health. One of these means is to provide the necessary medicines through its institutions and public health organizations. However, in Peru, 60% of the medicines required by the population are purchased in private pharmacies, despite the fact that these medicines are prescribed by public physicians. This situation is due to a failure in the medicines procurement processes, since these are mainly focused on the movement of stock in public pharmacies and not on the real medicines demands; in addition, these processes are not proper defined and do not have specific technological tools. The objective of this work is develop a proposal for improving the procurement process and provide the architecture design of a technological tool; this proposal wants to promote the collaboration between the entire health networks dedicated to the acquisition of medicines. This solution will be focusing not only in the stock from pharmacies, but also in the prescription of medicine and the morbidity of each corner of the country. Likewise, the solution contemplates a technological architecture within the reach of the Peruvian State, with redundancy, high availability and scalability. It is important to highlight that the proposed solution has been elaborated following business architecture approaches, where organization objectives prevail, and current techniques and methods of business architecture that allow easy understanding and subsequent implementation. / Tesis

Pandemics can significantly impact public health and society, for instance, the 2009 H1N1<br />and the 2003 SARS. In addition to analyzing the historic epidemic data, computational simulation of epidemic propagation processes and disease control strategies can help us understand the spatio-temporal dynamics of epidemics in the laboratory. Consequently, the public can be better prepared and the government can control future epidemic outbreaks more effectively. Recently, epidemic propagation simulation systems, which use high performance computing technology, have been proposed and developed to understand disease propagation processes. However, run-time infection situation assessment and intervention adjustment, two important steps in modeling disease propagation, are not well supported in these simulation systems. In addition, these simulation systems are computationally efficient in their simulations, but most of them have<br />limited capabilities in terms of modeling interventions in realistic scenarios.<br />In this dissertation, we focus on building a modeling and simulation environment for epidemic propagation and propagation control strategy. The objective of this work is to<br />design such a modeling environment that both supports the previously missing functions,<br />meanwhile, performs well in terms of the expected features such as modeling fidelity,<br />computational efficiency, modeling capability, etc. Our proposed methodologies to build<br />such a modeling environment are: 1) decoupled and co-evolving models for disease propagation, situation assessment, and propagation control strategy, and 2) assessing situations and simulating control strategies using relational databases. Our motivation for exploring these methodologies is as follows: 1) a decoupled and co-evolving model allows us to design modules for each function separately and makes this complex modeling system design simpler, and 2) simulating propagation control strategies using relational databases improves the modeling capability and human productivity of using this modeling environment. To evaluate our proposed methodologies, we have designed and built a loosely coupled and database supported epidemic modeling and simulation environment. With detailed experimental results and realistic case studies, we demonstrate that our modeling environment provides the missing functions and greatly enhances many expected features, such as modeling capability, without significantly sacrificing computational efficiency and scalability. / Ph. D.

Le déploiement des réseaux optiques d'accés et métropolitains à crée un besoin incessant de débits élevés et de portées étendues. Une demande pour des sources optiques compactes, polyvalentes, de bas coût et de consommation réduite a vu le jour dans ce contexte. Le but de cette thèse consiste à étudier expérimentalement et par la simulation deux techniques pour combattre les effets de la dispersion chromatique à travers l’ingénierie du chirp de la source. La première technique concerne les lasers DFB (Distributed Feedback Laser) modulés directement. Premièrement, un modèle complet et flexible d’un laser DFB développé au cours de la thèse a été exploité pour confirmer l’étude expérimentale des effets de phases du réseau de Bragg aux facettes sur le comportement du chirp. Les résultats ont montré l’existence de deux familles de lasers définies suivant la position du mode d’émission par rapport à la bande interdite. Deuxiémement, une étude théorique et expérimentale a montré la stabilisation et le contrôle du chirp des lasers DFB via la présence d'une rétroaction optique externe bien ajustée. La deuxième technique concerne le concept de la modulation duale des lasers modulateurs intégrés (D-EML : Dual Electroabsorption Modulated Laser) exploitant l’ajustement de la dérive en fréquence résultant de la juxtaposition d’une modulation de fréquence appliquée sur le laser et une modulation d’intensité appliquée sur le modulateur. L’évaluation expérimentale et théorique des performances du D-EML a permis de prouver sa compatibilité aux hauts débits (20, 25 et 40 Gb/s) ainsi que son efficacité par rapport à la modulation simple de l’EAM (Electro-Absorption Modulator). / Today, new higher-speed, low cost and low consumption optical sources are becoming a necessity for the deployment of access and metropolitan networks.The aim of this thesis is to study experimentally and by simulation two techniques in order to combat the chromatic dispersion effects through the chirp engineering of the source. The first technique concerns directly modulated DFB (Distributed FeedBack) lasers. First, a complete and flexible model of a DFB laser developed during the thesis has been used to confirm the experimental study of the facet phase effect on the chirp behavior. The results showed the existence of two laser’s families according to the position of the lasing mode with respect to the bandgap. Second, a theoretical and experimental study showed the chirp stabilization and control of DFB lasers due to the presence of a well adjusted external optical feedback.The second technique concerns the dual modulation concept of integrated modulated laser (D-EML : Dual Electroabsorption Modulated Laser) exploiting the adjustment of the chirp resulting from the juxtaposition of the frequency modulation applied to the laser and the intensity modulation applied to the modulator. Experimental and theoretical evalutation of D-EML performances has proven its compatibitlity with high bit-rates (20, 25 and 40 Gb/s) and its effectiveness with respect to the simple modulation of the EAM (Electroabsorption Modulator).

Au cours des dix dernières années, l’impact des questions de sécurité sur le développement et la mise en oeuvre des systèmes embarqués distribués n’a jamais cessé de croître. Ceci est principalement lié à l’interconnexion toujours plus importante de ces systèmes qui les rend vulnérables aux attaques, ainsi qu’à l’intérêt économique d’attaquer ces systèmes qui s’est simultanément accru. Dans un tel contexte, méthodologies et outils d’ingénierie des exigences de sécurité sont devenus indispensables pour prendre des décisions appropriées quant a` la sécurité, et ce le plus tôt possible. L’ingénierie des exigences devrait donc fournir une aide substantielle à l’explicitation et à la spécification des problèmes et solutions de sécurité des logiciels bien avant que concepteurs et développeurs ne soient engagés dans une implantation en particulier. Toutefois, et c’est particulièrement vrai dans les systèmes embarqués, les exigences de sécurité ne doivent pas être considérées seulement comme l’expression abstraite d’un ensemble de propriétés indépendamment de l’architecture système ou des menaces et des attaques qui pourraient y survenir. Nous estimons que cette considération est d’une importance capitale pour faire de l’ingénierie des exigences un guide et un moteur de la conception et de la mise en œuvre d’un système sécurisé. Notre approche s’appuie en particulier sur une approche centrée sur les connaissances de l’ingénierie des exigences de sécurité, applicable dès les premières phases de conception du système jusqu’à la mise en application des exigences de sécurité dans l’implantation. / During the last ten years, the impact of security concerns on the development and exploration of distributed embedded systems never ceased to grow. This is mainly related to the fact that these systems are increasingly interconnected and thus vulnerable to attacks, and that the economic interest in attacking them has simultane- ously increased. In such a context, requirement engineering methodologies and tools have become necessary to take appropriate decisions regarding security early on. Security requirements engineering should thus strongly support the elicitation and specifica- tion of software security issues and solutions well before designers and developers are committed to a particular implementation. However, and that is especially true in embedded systems, security requirements should not be considered only as the abstract expression of a set of properties independently from the system architecture or from the threats and attacks that may occur. We believe this consideration is of utmost importance for security requirements engineering to be the driving force behind the design and implementation of a secure system. We thus describe in this thesis a security engineering requirement methodology depending upon a constant dialog between the design of system functions, the requirements that are attached to them, the design and development of the system architecture, and the assessment of the threats to system assets. Our approach in particular relies on a knowledge-centric approach to security requirement engineering, applicable from the early phases of system conceptualization to the enforcement of security requirements.

Indiana University-Purdue University Indianapolis (IUPUI) / As the size of Twitter© data is increasing, so are undesirable behaviors of its users. One such undesirable behavior is cyberbullying, which could lead to catastrophic consequences. Hence, it is critical to efficiently detect cyberbullying behavior by analyzing tweets, in real-time if possible. Prevalent approaches to identifying cyberbullying are mainly stand-alone, and thus, are time-consuming. This thesis proposes a new approach called distributed-collaborative approach for cyberbullying detection. It contains a network of detection nodes, each of which is independent and capable of classifying tweets it receives. These detection nodes collaborate with each other in case they need help in classifying a given tweet. The study empirically evaluates various collaborative patterns, and it assesses the performance of each pattern in detail. Results indicate an improvement in recall and precision of the detection mechanism over the stand- alone paradigm. Further, this research analyzes scalability of the approach by increasing the number of nodes in the network. The empirical results obtained from experimentation show that the system is scalable. The study performed also incorporates the experiments that analyze behavior distributed-collaborative approach in case of failures in the system. Additionally, the proposed thesis tests this approach on a different domain, such as politics, to explore the possibility of the generalization of results.