The rise of disruptive technologies and the rapid growth of innovative initiatives have led to a trend of decentralization, deregulation, and distribution of regulated/centralized services. As a result, there is an increasing number of requests for the connection of distributed generators to distribution networks and the need for power utilities to quickly assess the impacts of distributed generators (DGs) to keep up with these requests. Grid integration of DGs brings about protection issues. Current protection systems were not designed for bi-directional power flow, thus the protective devices in the network lose their ability to perform their main functions. To mitigate the impact of distributed generation (DG), some standards and policies constrain the number of DG that can be connected to the distribution network. The problem with these limits is that they are based only on overload and overvoltage, and do not adequately define the DG size/threshold before the occurrence of a protection issue (NRS 097-2-3). The other problem with distributed generation is the vast difference in the technology, location, size, connection sequence, and protection scheme requirements which results in future DG network planning inadequacies – The Network DG Planning Dilemma. To determine the amount of DG to connect to the network, a detailed analysis is required which often involves the use of a simulation tool such as DIgSILENT to model the entire network and perform load flow studies. Modelling networks on DIgSILENT is relatively easy for simple networks but becomes time-consuming for complex, large, and real networks. This brings about a limitation to this method, planning inadequacies, and longer connection approval periods. Thus, there is a need for a fast but accurate system-wide tool that can assess the amount of DG that can be connected to a network. This research aims to present a technique used for calculating protection-based DG penetration limits on MV networks and develop a model to determine medium voltage opportunity network maps. These maps indicate the maximum amount of DG that can be connected to a network without the need for major protection scheme changes in South Africa. The approach to determining protection-based penetration limits is based on supervised machine learning methods. The aim is to rely on protection features present in the distribution network data i.e. fault level, Inverse Definite Minimum Time (IDMT) curve, pick-up current settings, Time Multiplier Settings (TMS), calculated relay operating times and relay positions to see how the network responds at certain DG penetration levels (‘actual' relay operating times). The dataset represents carefully anonymized distribution networks with accepted protection philosophy applied. A supervised machine learning algorithm is applied after nontrivial data pre-processing through recommendation systems and shuffling. The planning dilemma is cast into three parts: the first part is an automated pattern classification (logistic regression for classification of protection miscoordination), the second part involves regression (predicting operating time after different levels of DG penetration), and the last part involves developing a recommendation system (where, when and how much photovoltaic (PV) DG will be connected). Gradient descent, which is an optimisation algorithm that iterates and finds optimal values of the parameters that correspond to the local or global minimum values of the cost function using calculus was used to measure the accuracy of each model's hypothesis function. The cost function (one half mean squared error) for the models that predict ‘actual' relay operating times before DG penetration, at 35%, 65%, and 75% DG penetration converged to values below 120, 20, 15, and 15 seconds2 , respectively, within the first 100 iterations. A high variance problem was observed (cross-validation error was high and training error was low) for the models that used all the network protection features as inputs. The cross-validation and training errors approached the desired performance of 0.3±0.1 for the models that had second-order polynomials added. A training accuracy of 91.30%, 73.91%, 82.61%, and a validation accuracy of 100%, 55.56%, 66.67% was achieved when classifying loss of coordination, loss of grading and desensitization, respectively. A high bias problem was observed (cross-validation error was high and training error was high) for the loss of grading classification (relay positions eliminated) model. When the models (horizontal network features) were applied to four MV distribution networks, loss of coordination was not predicted, the loss of grading model had one false positive and the de-sensitization model had one false negative. However, when the results were compared to the vertical analysis (comparing the operating times of upstream and downstream relays/reclosers), 28 points indicated a loss of coordination (2 at 35%, 1 at 65% and 25 at 75% DG penetration). Protection coordination reinforcements (against loss of grading and desensitization) were found to be a requirement for DG connections where the MV transformer circuit breaker TMS is between 0.5 and 1.1, and where the network fault level is between 650 and 800A. Distribution networks in affluent neighbourhoods similar to those around the Western CapeSomerset West area and Gauteng- Centurion area need to be reinforced to accommodate maximum DG penetration up to the limit of 75% of the After Diversity Maximum Demand (ADMD). For future work, the collection of more data points (results from detailed analytical studies on the impact of DG on MV feeders) to use as training data to solve the observed high variance problem is recommended. Also, modifying the model by adding upstream and downstream network features as inputs in the classification model to solve the high bias problem is recommended.

Like many organizations, critical infrastructures and essential services are adopting cloud computing. The many benefits are however clouded with security concerns. These types of organizations and services are associated with severe societal and individual consequences from failures or incidents. They are naturally subject to strict regulations and requirements. Even if critical and essential services are adopting and utilizing cloud computing, organizations hesitate due to unsolved challenges with cloud computing for critical and essential services. To mitigate such unnecessary impediments and to enhance secure Health-CC, there is a need for an exploration of existing solutions for Health-CC, as well as investigating gaps, to provide improving considerations. To address this problem, the thesis investigated existing challenges and solutions for cloud computing security, regarding cloud computing within essential healthcare. Here, called “Health-CC”, and encompasses settings and processes where cloud computing is highly involved and where system, assets, and data protection are intensively actualized. The research question required the author to identify cloud computing challenges, thematize related solutions, patterns, gaps, and laying a basis for a well-based discussion on possible improving considerations – from a pertinent critical infrastructure protection perspective, for essential healthcare services. The chosen research question necessitated a problem-driven mixed methods approach, where a systematic literature review was utilized for the overall research guidance and selection procedures. Selection criteria were formulated to capture the mentioned Health-CC security settings. An integrated traditional literature review was added for the purpose of the scientific base. At the analysis level, the mixed methods approach facilitated a thematic synthesis analysis – to identify themes, patterns, and gaps or shortcomings, as well as lay the basis for following discussion of improving security considerations. Three solution groups were identified: specific techniques, software architecture, and assessment models. Further analysis of their solution types from a pertinent critical infrastructure protection perspective, identified multiple patterns: from recurring techniques or administrative components, targeted security issues, Health-CC environment focus, framework coverage, to the type of aspects and perspectives involved. This resulted in general patterns of solution components and perspectives, although revealing several shortcomings and possible improving considerations for enhanced Health-CC security: explicit critical infrastructure protection perspective; focus on continuity aspects; multi-party and multi-actor nature of Health-CC arrangement deserves more focus; system protection emphasis; availability concept and deterring properties highly considered; cloud environment specified when possible; data protection concerns only crucial and sensitive data required by law. Its conclusions on the exploration of solutions as well as improving considerations contribute to the HealthCC security field, to a satisfying degree.

Clostridium difficile est un pathogène entérique pouvant causer des diarrhées allant de modérées à sévères, des colites pseudomembraneuses et même la mort. Les traitements actuels contre la bactérie ont des taux de rechutes élevés. De plus, il n'existe pas à ce jour de vaccin permettant de prévenir l'infection. Cette étude épidémiologique porte sur la protection contre la colonisation et/ou la maladie conférée par la présence d'anticorps sériques naturels spécifiques aux antigènes de la bactérie. Nous avons développé un test ELISA (Enzyme-Linked ImmunoSorbent Assay) pour la détection des anticorps contre les toxines A et B de C. difficile et contre les protéines du flagelle (flagellines) dans des échantillons de sérum. Notre test ELISA servant à détecter les anticorps dirigés contre la toxine B a été calibré de façon à obtenir la meilleure corrélation possible avec le test de neutralisation de la cytotoxicité de la toxine B. Les paramètres du test ELISA ainsi mis au point ont été appliqués aux autres antigènes (toxine A et flagellines), pour lesquels un test de référence n'existe pas. Par la suite, nous avons tenté de définir le rôle de la réponse immunitaire humorale de l'hôte en corrélant les résultats de l'analyse des sérums de deux groupes de patients hospitalisés avec les informations sur le suivi des symptômes et la recherche de la présence de la bactérie dans les selles. Le premier groupe de patients nous a permis d'étudier la relation entre la survenue de la colonisation ou de l'infection par C. difficile et la production d'anticorps. Nos résultats montrent que les anticorps sériques ne semblent pas protéger le patient de l'implantation de la bactérie au tube digestif mais que suite à l'infection, une réponse humorale est mise en place contre les toxines du pathogène. Les patients du deuxième groupe, des patients hospitalisés infectés par C. difficile, ont été surveillés pour la survenue de symptômes sévères, du décès ou de rechutes suite à un épisode de maladie. Nous avons observé une plus grande prévalence d'anticorps sériques dirigés contre la toxine B et contre certaines flagellines chez les patients ayant eu une infection simple, sans complications ni rechutes. Les résultats de nos travaux indiquent donc que certains patients développent une réponse humorale contre les antigènes de C. difficile et que les anticorps produits, particulièrement ceux dirigés contre la toxine B, semblent impliqués dans la défense du patient contre la survenue de complications et de rechutes. Nos données laissent toutefois sous-entendre que d'autres caractéristiques de l'hôte contribuent de façon importante à la défense contre la colonisation et l'infection par C. difficile. Des travaux supplémentaires sont nécessaires afin de définir les paramètres qui permettront d'élaborer un protocole de vaccination optimal contre C. difficile.

State-of-the-art solar-thermal flat-plate collectors suffer from a limited potential to decrease production costs for the necessary higher economic benefit of so-lar-thermal systems. Costly metallic materials and corresponding manufactur-ing processes prevent further cost reductions. For that issues, plastic materials can offer a promising approach. The main hurdle for the use of cost-effective plastics lies in the high thermal loads on the collector components — absorber and insulation — which were identified in a field-testing. The necessary overheating protection approaches to lower these thermal loads were investigated in a literature review. A large number of relevant concepts was evaluated related to achievable temperature reduction, influence on solar yield, additional costs and intrinsic safety. There-fore, a mathematical model was developed to determine the solar-thermal col-lector´s behaviour in a solar-thermal system for hot water and space heating. This way, the most promising overheating concepts were simulated and ana-lysed with regard to component temperatures and system performance. Omitting the selective absorber coating and reducing the backside insulation was found to be the most suitable solution for component materials with limited temperature resistance like polypropylene. In the second part of the research, collector design concepts were developed on the basis of the characteristics of plastic material processing. The identified unit costs showed savings of more than 50 % in comparison to stateof- the-art collectors. The analysis regarding temperature loads and annual solar yield by simulation proved the performance of the concepts. The collector costs and the simulation results were used to define the total costs of the solar-thermal sys-tems and to evaluate the economic benefits by means of the collector con-cepts. The benefits were similar to state-of-the-art set-ups. Thus, further adjustments at system level are necessary to lower the total costs. Therefore, the system set-up has to be harmonised with the collector requirements and investigated in detail.

This study has aimed at examining the nature and function of the support and protection that is offered and provided to human rights defenders trough a selected few international as well as regional human rights instruments and mechanisms, among them the Declaration on Human Rights Defenders, the EU Guidelines on Human Rights Defenders as well as the Inter-American Commission on Human Rights and the Inter-American Court on Human Rights. In order to conduct such a study in a fairly limited and concrete way a number of cases were selected of human rights defenders who have undergone or are currently undergoing criminal prosecution and are incarcerated in Guatemala. The selection was based on the notion that apart from murder, criminal prosecution and incarceration of human rights defenders constitutes one of the most harmful and effective ways to actively hinder the continuance of valuable human rights work. Consequently, it impedes the promotion, implementation and protection of human rights on a general level. In regards to this States such as Guatemala have found ways to circumvent their international human rights duties by allowing others or themselves to label human rights defenders as criminal and violent actors, thus taking away the legitimate aspect of their roles and functions when it comes to promoting and safeguarding the enjoyment and exercise of human rights. The examined cases were meant to shed light on the situation for defenders in Guatemala but most importantly they were meant to illustrate a context in which one can examine the role and function that international human rights instruments and mechanisms have to combat such types of situations. The study found that although the concerned instruments and mechanisms such as the Declaration on Human Rights Defenders, the EU-guidelines on Human Rights Defenders, the Inter-American Commission on Human Rights and the Inter-American Court on Human Rights have a positive, important and impacting role in providing support to human rights defenders they have not yet reached/obtained the function of preventing persecution of human rights defenders, most notably of the legal kind. Since these mechanisms can only recommend but not force States to recognize and treat advocates of rights as “human rights defenders” their role and function for this specific purpose becomes less effective. All is not negative however, and the instruments and mechanisms that exist today are an illustration of the ambitions of States to follow international human rights principles and standards, at least to some extent.

This research applies a recently developed dynamic state-estimation based protection scheme, the settingless protection, to the photovoltaic (PV) industry for the first time. At this time, the proposed protection algorithm has been implemented on traditional protection zones for individual power system devices, but this research extends this protection to a microgrid, specifically, a system of PV network composed of several PV modules. Several illustrative examples on various anomalies such as high impedance faults and shorted-out PV modules have been provided to demonstrate the effectiveness of this protection scheme. The detection of these anomalies has been demonstrated in the presence of changing atmospheric conditions, and with the operation of maximum power point tracking (MPPT) equipped dc-dc converters. This protection scheme requires an accurate model of the PV module, therefore, a two-diode PV model has been developed using quadratic integration modeling. In this PV model development, a scaling factor is applied to the Taylor series expansion of the exponential terms of the model of the PV module. Then the higher order terms of the Taylor series expansion are reduced to at most second order terms using the quadratization technique. Furthermore, a novel approach for extracting the PV parameters, namely, the ideality constants, leakage currents, PV module internal current, shunt and series resistances, has been presented. A comparison was performed between numerically generated data using the determined PV module parameters and data measurements from a physical PV module. It was shown that the maximum error from this comparison was below 0.12A, and less than 0.05A around the maximum power point region of the PV modules used for this research. The residual data from the PV array protection scheme has been used to develop a method for identifying the location of faulted PV modules. Also, condition-based monitoring of the PV array system has also been presented with examples. From the PV array system monitoring, the shading and underperformance of a PV module have been identified. From the contributions of this research, an accurate module of the PV array has been developed in a form that can be integrated with other power system devices. This accurate module can be used for state estimation of the PV array, load flow analysis, short circuit analysis, and other power system analytical studies. Also, by determining the location of the faulted PV module, the time to identify this faulted PV module in a large PV installation is drastically reduced. Lastly, by identifying shading conditions and underperforming PV modules, the PV system operator can quickly bring the underperforming module or modules to optimal performance, thereby, maximizing the power yield of the PV array, and maximizing the revenue of the PV system owner.

Escherichia coli has evolved in environments which may commonly be acidic and thus developed adaptive mechanisms to minimise acid-induced damage. It has previously been observed that adapted bacteria to moderately acidic conditions can grow in media considerably below their optimum growth pH. To explain this phenomenon, a hypothesis which suggested that diffusible molecules (alarmones) may serve as early warning systems of acidic conditions was proposed. Alarmones are thought to be produced upon exposure to mildly-acidic conditions. They then diffuse in the environment and elicit a protective response against acid in recipient cells. The protective activity of those putative alarmones against lethal acid was investigated. The main aim of this project is to determine the mode of action of those alarmones at the molecular level. Preliminary experiments confirmed acid resistance conferred by alarmones to populations of E. coli C600. The stability of those alarmones at different temperatures and following proteinase K treatment was investigated. Moreover, investigations into whether alarmones are autoinducer-2 (AI-2) molecules and whether alarmones increase the percentage of persisters in an E. coli population were undertaken. Subsequently, microarray analyses of both alarmone-induced and non-induced cultures were performed to reveal E. coli genes induced by alarmones. Moreover, proteomic studies using two-dimensional gel electrophoresis were conducted to reveal proteins induced by alarmones. Supernatants from alarmone-induced cultures conferred statistically significant protection (p<0.01) on recipient cultures against lethal acid (pH3). Alarmones were inactivated by heat (60oC) and by proteinase K. The autoinducer-2 (AI-2) assay revealed that alarmones are not AI-2 molecules. In addition, alarmones did not increase the percentage of persisters. In order to elucidate potential mechanisms for alarmone-mediated protection, the genomic expression and protein induction of alarmone-induced cells using microarray analysis and two-dimensional gel electrophoresis, respectively, were performed. Two-dimensional gel electrophoresis of transduced cultures indicated that around 13 proteins were induced in the alarmone-protected populations of E. coli C600. Mass-spectrometric analysis revealed that these alarmone-inducible proteins include the acid stress chaperone HdeB and the DNA-binding transcriptional dual regulator, H-NS which plays an important role in stress adaptation. Microarray analyses of transduced cultures indicated that 671 open reading frames (ORFs) were significantly differentially expressed between alarmone-protected and control populations (p<0.05). 508 ORFs were upregulated in the induced cells including 10 genes related to acid-resistance and 36 different genes related to multidrug efflux system proteins whereas 163 ORFs including the autoinducer-2 system were downregulated. E. coli releases diffusible signalling compounds which mediate adaptation to acid stress of recipient cells. Microarray and proteomic data show that two acid fitness island genes (hdeB and hdeD) and three genes that encode the antiporters of the three amino-acid-dependent acid resistance mechanisms (gadC, adiC and cadB) were among the upregulated genes. This work confirms that there is communication between bacterial cells in general and warning messages amongst E. coli C600 cells in particular in the presence of stress.

Products that children get in contact with every day, such as toys, paints, electronics and detergents have recently been discovered that they contain harmful chemicals. Children are more susceptible than adults because of their thin skin and yet not fully developed bodies. The purpose of this work is to identify the risks from chemicals that children in the indoor nursery get in contact with, and how these products affect the health of children, and to describe how these chemicals affect children's health and the environment. The aim is also to find out how great the level of the staff's knowledge is about the harmful chemicals, as well as the preventive measures taken.  This is done through a survey among the staff at nurseries in Båstad municipality. The report consists of three parts, two practical parts in the form of an on-site investigation at nine kindergartens in Båstad municipality and a survey among the staff who worked there. The third theoretical part was in the form of literature.  The results of this study show that the indoor environment in nurseries has important significance for children's health. The inventory of nursery in Båstad municipality showed that today there are goods and products with harmful chemicals among kids at nurseries. The products that have been found in nurseries in Båstad municipality where most contain harmful chemicals such as phthalates, flame retardants, perfluorinated substances and bisphenol A. It was above all the electronic toys such as cell phones, keyboards, computers, and even in the older toys or soft and semi-soft toys.  To reduce the amounts of chemicals found in nurseries one should start to throw away old toys, old electronic toys, avoid toys with batteries or electronics that do not have their batteries covered, stop using cleaning products containing chemicals and also increase the number of times that the nurseries are cleaned thoroughly. The questionnaire study showed that most nurseries were not sufficiently aware of the dangerous chemicals in toys and detergents used. There was a certain part of the staff that was aware of what "green flag" means.  To achieve this is the best way, the municipality, and politicians should help the nurseries. Improvements by the municipality, and politicians should provide important training for both nurseries staff and for the various pictures within the community that directly or indirectly impact. In order to improve knowledge in this area it is needed to train nurseries staff, cleaning staff, parents and others in the business. To get a non-toxic nursery, it is important that the municipality, the nurseries staff, cleaning staff and parents all gain knowledge about chemicals in materials and products.

This study investigates the role of privacy and data protection in the implementation of e-government in developing countries. It examines the privacy and data protection issues which arise when e-government is introduced in Ghana. E-government is a way that governments liaise with their various departments and agencies through the use of information and communication technologies (ICTs). Through e-government, governments are able to provide better, effective and efficient services to their citizens. This new form of governments’ delivering services electronically to their citizens, businesses and various departments potentially offers benefits (for example, economic development, low costs and improved services) to society. However the implementation of e-government carries potential risks to users. The potential for online identity theft and fraud raises privacy concerns. From a theoretical foundation, fieldwork in Ghana, through interviews and focus groups, is used to investigate the issue of privacy and data protection in e-government implementation in an empirical setting. Interviewees included senior civil servants, political leaders, members of the Select Committee on Communication, academics, university students as well as stakeholders from private and public organisations. The research borrowed from the Straussian grounded theory approach as a technique to analyse the fieldwork data. The results of the study indicate that privacy and data protection does not currently play a significant role in e-government implementation in a developing country such as Ghana. Other factors such as access to information and communication technologies (Internet accessibility) and e-skills were found to be challenges which significantly impact individuals’ use of e-government. The study found that there is a low privacy concern among Ghanaian citizens. This was found to be significantly related to a lack of awareness of privacy issues; and also the national cultural dimensions of Ghanaian society. The study concludes by emphasising the importance of government investing in ICT infrastructure and public education to raise awareness of e-government services, as well as privacy and data protection issues. Implications for research and policy makers are discussed. The study suggests future research to investigate the further impact of privacy awareness on individuals’ adoption of e-government in a collectivist society such as Ghana.

published_or_final_version / Computer Science and Information Systems / Master / Master of Philosophy