Recent events, such as the Northeast Blackout of 2003, have highlighted the need for accurate real-time stability assessment techniques to detect when an electric power system is on the brink of voltage collapse. While many techniques exist, most techniques are computationally demanding and cannot be used in an on-line application. A voltage stability index (VSI) can be designed to estimate the distance of the current operating point to the voltage marginally stable point during the system operation. In this research work, a new VSI was developed that not only can detect the system voltage marginally stable point but also is computationally efficient for on-line applications. Starting with deriving a method to predict three types of maximum transferable power of a single source power system, the new VSI is based on the three calculated load margins. In order to apply the VSI to large power systems, a method has been developed to simplify the large network behind a load bus into a single source and a single transmission line given the synchronized phasor measurements of the power system variables and network parameters. The simplified system model, to which the developed VSI can be applied, preserves the power flow and the voltage of the particular load bus. The proposed voltage stability assessment method, therefore, provides a VSI of each individual load bus and can identify the load bus that is the most vulnerable to voltage collapse. Finally, the new VSI was tested on three power systems. Results from these three test cases provided validation of the applicability and accuracy of the proposed VSI.

Submitted in partial compliance with the requirements for the Master of Technology: Chiropractic, Durban University of Technology, 2014. / Background: Poor balance is a risk factor for injury in adolescent sport including soccer. Despite the rapid growth in female adolescent soccer especially in South Africa, the association between balance and injury in this population has not been fully explored. This study aimed to determine the relationship between injury and balance. Static and dynamic balance was monitored as sway index (SI) and limits of stability direction control (LOSDC). Objectives: The objectives of this study were to determine the body mass index of adolescent female soccer players; to determine the prevalence of injury in adolescent female soccer players; to determine static balance as revealed by the sway index (SI); to determine dynamic stability as revealed by limits of stability direction control (LOSDC) and to correlate body mass index (BMI) to sway index and limits of stability. Method: Eighty adolescent female soccer players, between the ages of fourteen and eighteen, were recruited through convenience sampling from schools in the eThekwini district of KwaZulu-Natal. After obtaining informed consent and assent, participants completed questionnaires and were scheduled for the balance and BMI assessments. The objective data for each participant consisted of height, weight, Sway Index (SI) and Limits of Stability Direction Control (LOSDC) readings, measured using a stadiometer, electronic scale and Biodex Biosway Balance System (Biodex Medical Systems Inc., Shirley, New York) respectively. The subjective and objective data were analyzed using SPSS version 21.0 (SPSS Inc. Chicago, Ill, USA). Statistical tests included descriptive statistics using frequency and cross-tabulation. Inferential statistics using t-tests and Pearson’s correlations at a significance level of 0.05 was also incorporated. The testing of hypotheses was performed using Fisher’s Exact tests for nominal data and ordinal data. A p value of < 0.05 was considered as statistically significant. The statistical analysis also included Odds Ratio calculations. Results: The mean body mass index of the injured participants was 23.54±3.56 kg/m2 and the mean body mass index of the uninjured participants was 23.00±4.63. Only 27.5% of the participants sustained an injury. Injured participants performed poorly on average in the SI assessment involving their eyes open when standing on a soft surface. The results were similar for the LOSDC in the overall, right, left, backward-right and backward-left directions. However, there were no significant correlations calculated. Significant relationships existed between BMI and the SI assessments in the injured participants which involved standing on a firm surface with their eyes open (p = 0.05), their eyes closed when also standing on a firm surface (p = 0.05), their eyes open when standing on a soft surface (p = 0.02), and their eyes closed when standing on a soft surface (p = 0.04). A significant relationship also existed between BMI and LOS right direction control (p = 0.02). Conclusion: This research paper revealed that the body mass index as investigated in this study is similar to other studies involving female adolescents; soccer injury as investigated in this study is similar to other studies involving female adolescents; poor static and dynamic balance is not associated with injury in adolescent female soccer players and lastly, body mass index is linked to the balance of an individual.

Les tâches réalisées en traitement d'image tendent à devenir de plus en plus complexes. Par exemple, dans le contexte routier, les systèmes d'aide à la conduite, (Advanced driver-assistance systems), visent à une automatisation complète de la tâche de conduite. L’évaluation de la fiabilité représente un enjeu important pour ce type d’application. Face à la difficulté des tâches à réaliser, les chaînes de traitements sont souvent divisées en de nombreuses étapes de calculs de sorte qu'il est difficile de caractériser les sorties de la chaîne en fonction des perturbations des entrées. Les étapes du traitement consistent le plus souvent en des problèmes formulés comme la minimisation d'une énergie. Cette énergie est généralement difficile à optimiser, ce qui nécessite la mise en œuvre de méthodes d’optimisation adaptées. Dans cette thèse, nous cherchons à caractériser la solution d’un traitement à partir des calculs réalisés au cours de l’étape d'optimisation. Cette approche nous a permis de proposer des indices de stabilité de la solution dans le cadre de deux méthodes d’optimisation discrètes : la coupure de graphe et la programmation dynamique. Tout d’abord, nous nous sommes intéressés au problème de la reconstruction stéréoscopique en contexte routier et au dé-bruitage, dans le cadre de l’optimisation par coupure de graphe. Les modèles issus de l’interprétation bayésienne amènent à optimiser des énergies qui ne peuvent pas être traitées avec les schémas d’optimisation classiques par fusion binaire. Nous avons proposé un schéma adapté qui met en jeu des fusions binaires par expansion et par saut. L’application de ce schéma aux problèmes de la reconstruction stéréoscopique et au dé-bruitage, nous a permis d’obtenir des solutions possédant les caractéristiques que nous recherchions : des contours d’objets nets et des dégradés progressifs dans les zones homogènes. Ensuite, dans le contexte de la programmation dynamique, nous avons réinterprété l’a priori mis en jeu dans la méthode de reconstruction Semi-Global Matching ainsi que certaines de ses variantes. Nous avons proposé d’ajouter un paramètre à ces méthodes afin de modifier les directions privilégiées par l’a priori. Enfin, nous avons proposé des indices de stabilité de la solution dans le cadre de la coupure de graphe et de la programmation dynamique. La prise en compte de ces indices, dans une étape de raffinement des solutions, permet une amélioration des résultats / Problems solved by image processing tend to be more and more complex. For instance, in road context, ADAS (Advanced driver-assistance systems) aim to a completely automatic diving tack. Evaluating system reliability is an important challenge in that case. These tasks being hard to perform, processing chains are often divide in numerous processing steps. As a consequence, characterizing the output using the input of the chain is not obvious. Most of the time, image processing steps are formulate as an energy minimization. These energies are often hard to minimize and need to apply suitable optimization methods. In this thesis, we aim to characterize the solution during the optimization step. Using this approach, we proposed stability index with two discrete optimization methods : graph-cut and dynamic optimization. First, we focused on stereoscopic reconstruction problem in road context and on denoising problem using graph-cut. Models obtained by Bayesian interpretation lead to optimize energies witch cannot be handled by classical binary fusion optimization scheme. We proposed a suitable scheme composed of fusion by expansion and fusions by step. When this scheme is apply to stereoscopic reconstruction and denoising, obtained solution have the wanted characteristics : sharp edges and shading in homogeneous areas. Next, in dynamic programming context, we reinterpreted the prior used in Semi-Global Matching (SGM) stereoscopic reconstruction method and in some of its variants. We proposed an additional parameter in order to modify the favored direction in the prior. At last, we proposed stability index of the solution in graph-cut and dynamic programing context. Using this index in a solution refinement step shows improvements

An increase in demand for electric power has forced utility transmission systems to continuously operate under stressed conditions, which are close to instability limits. Operating power systems under such conditions along with inadequate reactive power reserves initiates a sequence of voltage instability points and can ultimately lead to a system voltage collapse. Significant research have been focused on time-synchronized measurements of power systems which can be used to frequently determine the state of a power system and can lead to a more robust protection, control and operation performance. This thesis discusses the applicability of two voltage stability synchrophasor-based indices from literature to analyze the stability of a power system. Various load flow scenarios were conducted on the BPA 10-Bus system and the IEEE 39-Bus System using PowerWorld Simulator. The two indices were analyzed and compared against each other along with other well-known methods. Results show that their performances are coherent to each other regarding to voltage stability of the system; the indices can also predict voltage collapse as well as provide insight on other locations within the system that can contribute to instability.

Thesis (MEng) -- Stellenbosch University, 2014. / ENGLISH ABSTRACT: The Dorsiflexometer is a device designed and built for the assessment of a patient’s balance capabilities. The birth of the Dorsiflexometer is due to a serious need for physiological balance assessment equipment, capable of conducting dynamic tests in the clinical setting. This is accomplished by recording and analysing the patient’s response to sagittal plane perturbations. The Dorsiflexometer is operated from a computer software interface program. It uses the measurements from a single force plate to calculate four balance metrics’ characterising a patient’s ability to maintain balance. These balance metrics include the sway index, equilibrium score, postural stability index and radius parameter. A single and a double inverted pendulum model of the human body is derived to calculate a patient’s centre of mass movement in the sagittal plane with the measured force plate data and body parameters. Three experiments, involving 48 subjects, were conducted. The experimental tests proved the competency of the machine, the accuracy of both inverted pendulum models and the balance response of seafarers aboard an Antarctic research and supply vessel during rough sea conditions. The tests concluded that the inverted pendulum models can be used to calculate the body centre of mass displacement. The double inverted pendulum model results are more accurate compared with the single inverted pendulum model. During rough sea conditions, the body movement and postural response of seafarers are increased in order to keep themselves upright. The body is furthermore exposed to a fluctuating ground reaction force which may lead to the progression of osteoarthritis and musculoskeletal injuries. The Dorsiflexometer proved to be capable of conducting repeatable assessments and yielding accurate results which can be used to distinguish between balance capabilities. / AFRIKKANSE OPSOMMING: Die Dorsiflexometer is ’n apparaat wat die balansvermoë van pasiënte analiseer. Die masjien is ontwerp en vervaardig weens die groot behoefte aan fisiologiese balans assesserings toerusting wat dinamiese toetse in die mediese sektor kan bepaal. Dit word bereik deur pasiënte se liggaamsreaksie in die sagittale vlak te meet en te assesseer. Die Dorsiflexometer is beheerbaar vanaf ’n rekenaar sagteware koppelvlak program. Die masjien maak gebruik van ’n enkele kragplaat om pasiënte se balans statistieke te meet. Hierdie balans statistieke wat die pasiënte se balans vermoë beskryf en karakteriseer behels die sogenaamde: swaai indeks, balans telling, posturale stabiliteit indeks en die radius parameter. ’n Enkel en dubbel inverse slinger model van die liggaam is afgelei. Hierdie modelle maak gebruik van ’n pasiënt se kragplaat metings en sy liggaamlike parameters om die swaartepunt tydens beweging te bereken. Drie eksperimente, waarin 48 persone betrokke was, is gedoen. Die eksperimente is gedoen om die apparaat se bevoegdheid te bewys, die akkuraatheid van altwee inverse slinger modelle te toets en verder die balans van seevaarders op die Antarktiese navorsings en toevoer skip tydens rowwe see toestande te analiseer. Die toetse het bewys dat die inverse modelle gebruik kan word om die liggaam se swaartepunt te bereken. Die dubbel inverse slinger model resultate is wel akkurater as die enkel slinger model. Daar is bevind dat seevaarders van meer liggaamsbeweging en posturale reaksies gebruik moet maak om orent te bly tydens rowwe seetoestande. Verder word hul liggame blootgestel aan ’n wisselende grond reaksie krag wat kan lei tot die ontwikkeling van osteoarthritis en muskuloskeletale beserings. Die Dorsiflexometer is bewys as ’n aparaat wat wat akurate resultate lewer vir herhaalbare assesserings. Dit kan gebruik word om te onderskei tussen verskillende balans vermoëns.

The diploma thesis focuses on the fluctuation of production workers specific establishment company Vodňanská poultry, a. s. The first part is devoted to explanation of the theoretical notions related to the topic - the most frequent causes, the methods of measurement or the costs associated with the departures of employees. Theoretical knowledges are in the next stage applicate for analysis and evaluation of the situation of the selected company. The final part contains suggestions for improving identified problems to reduce fluctuation.

This diploma thesis is focused on the fluctuation of employees of the finance department in a selected company. The first part is devoted to the issue of employee’s fluctuation and human resources management related to this topic. Theoretical knowledge is used in the next phase to analyze and evaluate the situation in the selected company. Finally, solutions will be proposed that will reduce fluctuations in society.

Submitted in partial compliance with the requirements for the Master of Technology: Chiropractic, Durban University of Technology, 2014. / Background: Poor balance is a risk factor for injury in adolescent sport including soccer. Despite the rapid growth in female adolescent soccer especially in South Africa, the association between balance and injury in this population has not been fully explored. This study aimed to determine the relationship between injury and balance. Static and dynamic balance was monitored as sway index (SI) and limits of stability direction control (LOSDC). Objectives: The objectives of this study were to determine the body mass index of adolescent female soccer players; to determine the prevalence of injury in adolescent female soccer players; to determine static balance as revealed by the sway index (SI); to determine dynamic stability as revealed by limits of stability direction control (LOSDC) and to correlate body mass index (BMI) to sway index and limits of stability. Method: Eighty adolescent female soccer players, between the ages of fourteen and eighteen, were recruited through convenience sampling from schools in the eThekwini district of KwaZulu-Natal. After obtaining informed consent and assent, participants completed questionnaires and were scheduled for the balance and BMI assessments. The objective data for each participant consisted of height, weight, Sway Index (SI) and Limits of Stability Direction Control (LOSDC) readings, measured using a stadiometer, electronic scale and Biodex Biosway Balance System (Biodex Medical Systems Inc., Shirley, New York) respectively. The subjective and objective data were analyzed using SPSS version 21.0 (SPSS Inc. Chicago, Ill, USA). Statistical tests included descriptive statistics using frequency and cross-tabulation. Inferential statistics using t-tests and Pearson’s correlations at a significance level of 0.05 was also incorporated. The testing of hypotheses was performed using Fisher’s Exact tests for nominal data and ordinal data. A p value of < 0.05 was considered as statistically significant. The statistical analysis also included Odds Ratio calculations. Results: The mean body mass index of the injured participants was 23.54±3.56 kg/m2 and the mean body mass index of the uninjured participants was 23.00±4.63. Only 27.5% of the participants sustained an injury. Injured participants performed poorly on average in the SI assessment involving their eyes open when standing on a soft surface. The results were similar for the LOSDC in the overall, right, left, backward-right and backward-left directions. However, there were no significant correlations calculated. Significant relationships existed between BMI and the SI assessments in the injured participants which involved standing on a firm surface with their eyes open (p = 0.05), their eyes closed when also standing on a firm surface (p = 0.05), their eyes open when standing on a soft surface (p = 0.02), and their eyes closed when standing on a soft surface (p = 0.04). A significant relationship also existed between BMI and LOS right direction control (p = 0.02). Conclusion: This research paper revealed that the body mass index as investigated in this study is similar to other studies involving female adolescents; soccer injury as investigated in this study is similar to other studies involving female adolescents; poor static and dynamic balance is not associated with injury in adolescent female soccer players and lastly, body mass index is linked to the balance of an individual.

En Guadeloupe, l'utilisation de composts se heurte à de nombreux freins, aussi bien en termes de leur qualité qu’en termes d’un manque de plateformes de compostage à grande échelle et de proximité. Des études récentes ont montré que la qualité des composts locaux était plus faible qu’en milieu tempéré, ce qui constituerait un verrou majeur à l’adoption de la pratique et l’utilisation des composts industriels locaux. Pourtant, les objectifs de valorisation des déchets organiques fixés par les instances publiques sont ambitieux et le gisement local, bien que diffus et actuellement mal géré ou négligé, présenterait un réel intérêt pour la profession agricole à être orienté vers la valorisation biologique telle que le compostage. Dans ce contexte, l’objectif de ce travail était d'évaluer la qualité des composts élaborés en milieu tropical et d'apporter des éléments factuels pour son amélioration et, plus spécifiquement, d’apporter de l’information sur les potentialités agronomiques du compostage des effluents d’élevage en Guadeloupe, présentant ainsi le compostage comme une alternative durable pour le recyclage des déchets d’origine animale.Une méta-analyse de 442 composts d'origine diverse, la première réalisée sur le sujet, nous a permis de démontrer que les composts produits en milieu tropical présentent des teneurs en carbone, azote, potassium et fraction soluble de la matière organique plus faibles que celles des composts produits en milieu tempéré, et que cela pourrait notamment être dû à l’influence des conditions climatiques lors du compostage. En revanche, nous avons pu mettre en évidence que certaines matières premières permettaient l’obtention de composts de meilleure qualité quelque soit le climat considéré, il s’agissait entre autres des effluents d’élevage.Les résultats issus d'une série d’expérimentations menée sur la production de composts d’effluents d’élevage avec co-compostage et vermicompostage ont été traités avec une approche méthodologique innovante dans ce domaine, les Réseaux Bayésiens. L’évaluation réalisée sur le co-compostage effluents/déchets verts nous a permis d’identifier l’"effet de concentration" du carbone et de la lignine, comme celui qui définit la qualité des composts en termes de quantité et de stabilité de la matière organique. En revanche, dans le cas des nutriments, seule la qualité des matières premières a été identifiée comme le facteur déterminant de la qualité des produits finaux. Ces résultats nous ont amené à considérer les effluents d’élevage de bovin comme la matière première la plus efficace pour produire des co-composts de qualité satisfaisante, répondant à la problématique d’usure de la matière organique des sols guadeloupéens et permettant de satisfaire les attentes de la profession agricole.De plus des expérimentations réalisées sur les composts domestiques ont montré que la gamme analysée présentait une variabilité trop importante pour être considérée comme acceptable par la profession agricole. Le compostage domestique peut permettre de produire des composts de bonne qualité agronomique à utiliser à la petite échelle des jardins particuliers et des jardins créoles. / In Guadeloupe, the practice of composting faces many obstacles and preconceptions both in terms of quality and in terms of lack of large-scale composting plants as well as local composting facilities. Recent studies have shown that the quality of local composts was lower compared to those from temperate regions. This constitutes an important constraint for the adoption of the former by farmers. However, organic waste recovery targets set by the government are ambitious and local resources, although diffused and currently poorly managed or neglected would be of real interest for the farming profession by being directed towards organic recycling such as composting. In this context, the aim of this thesis was to evaluate the quality of compost produced in the tropics, provide factual elements for improvement and, more specifically, to provide information on the agronomic potential of composting livestock manure in Guadeloupe, presenting composting as a sustainable alternative for the recycling of animal waste.A meta-analysis of 442 composts from various sources, the first one to be conducted on the subject enabled us to demonstrate that composts produced in the tropics present lower contents of carbon, nitrogen, potassium and soluble fraction of organic matter than those produced in temperate environments. This could especially be due to the influence of climatic conditions during composting. However, we were able to show that some raw materials allow better quality composts whatever the considered climate, especially the case of livestock manure.A series of experiments conducted on the production of livestock manure composts with co-composting and vermicomposting were treated with an innovative methodological approach in this field, the Bayesian Networks. The evaluation carried out on co-composting has allowed us to identify that the "concentration effect" was the main factor affecting compost quality in terms of amount and stability of organic matter. While in the case of nutrients, only the quality of raw materials has been identified as the determining factor affecting the quality of the end products. These results led us to consider manure, mainly cattle manure, as the most efficient feedstock for producing satisfactory quality composts, meeting the needs of loss of soil organic matter in Guadeloupe and the needs of the farming profession.Further experiments performed on household composts showed that their quality exhibited a too important variability to be considered acceptable by farmers. Our results indicate that household composts could be suitable for use in small-scale private gardens and Creole gardens.

The thesis deals with the analysis of competitiveness of the Visegrad Group. The aim of this thesis is to analyze the competitiveness of the Visegrad countries - the Czech Republic, Hungary, Poland and Slovakia. The countries will be examined in today's competitive environment within the Visegrad Group and the European Union. The analyze is based on data available from public sources and statistics. The work is divided into three chapters. The first part is devoted to the theoretical definition of competitiveness and methods of how to measure the competitiveness of the state. The second chapter introduces Visegrad Group and its common characteristics. The another part of the work is focused on the macroeconomic indicators - inflation, government debt and GDP per capita. The foreign trade and territorial and commodity structure of exports in the last ten years are also examined in this part. In the third chapter there is an analysis of the competitiveness based on investigation of labor productivity, labor costs, expenditures on research and development and tertiary education. In conclusion there is an evaluation of competitiveness of Visegrad Group based on the Global Competitiveness Index in 2011-2012.