This master thesis examines technical requirements for small hydro power plants (HPP) to operate proximate parts of the power grid in island mode. The work examines how small hydropower can be modified and complemented with additional technologies to achieve sufficient frequency control capabilities. A case study was performed within the concession area of power grid operator Ålem Energy. One of the HPPs, located in Skälleryd, is owned by Ålem Energy and became the focal point of the study. Relevant parts of the concession area were surveyed for properties such as system inertia, electric load and available power. Furthermore, a model of Kaplan turbine 1 in Skälleryd HPP was created with the purpose of studying the benefits of bypassing regulation control from the wicket gates directly to the runner. The method was tested in an off-grid islanding test. Frequency control of the turbine was tested powering electric heaters and, using a new method, controlling a virtual power grid. Finally, a theory was developed to estimate the transient disturbance resilience (TDR) of a power grid. The theory was applied to the HPP in Skälleryd to suggest modifications for the plant to achieve sufficient islanding capabilities. The survey of the power system revealed a promising potential for the HPPs to operate in island mode, especially at later stages when the grid spans several HPPs for more system inertia. The available power from the HPPs was however strongly seasonal which imposes flexibility on a future plan of action for engaging the grid in island mode. The method of controlling the turbine power from the runner proved to have several difficulties. Firstly, the current hydraulics system was not able to freely control the runner as the hydrodynamic forces on the runner blades were too large. Secondly, the method was found to be unstable due to inherent amplification of speed deviations. Furthermore, the low inertia at Skälleryd is likely detrimental to the lone frequency control of the turbine. Therefore other methods for improving frequency control were suggested. The developed theory for TDR was used to create charts describing the TDR for various combinations of system inertia and regulation speed. By studying the proprieties of Skälleryd HPP in the charts the necessary modifications could be rationally chosen. A frequency regulating dummy load was found to be the simplest option. A control scheme was suggested with the dummy load performing primary frequency control and the turbines at Skälleryd performing secondary control, restoring the dummy load to its nominal state.

Esta dissertação de mestrado apresenta os resultados de uma investigação sobre os métodos de co-estimativa comumente utilizados em geoestatística. Estes métodos são: cokrigagem ordinária; cokrigagem colocalizada e krigagem com deriva externa. Além disso, a krigagem ordinária foi considerada apenas a título de ilustração como esse método trabalha quando a variável primária estiver pobremente amostrada. Como sabemos, os métodos de co-estimativa dependem de uma variável secundária amostrada sobre o domínio a ser estimado. Adicionalmente, esta variável deveria apresentar correlação linear com a variável principal ou variável primária. Geralmente, a variável primária é pobremente amostrada enquanto a variável secundária é conhecida sobre todo o domínio a ser estimado. Por exemplo, em exploração petrolífera, a variável primária é a porosidade medida em amostras de rocha retiradas de testemunhos e a variável secundária é a amplitude sísmica derivada de processamento de dados de reflexão sísmica. É importante mencionar que a variável primária e a variável secundária devem apresentar algum grau de correlação. Contudo, nós não sabemos como eles funcionam dependendo do grau de correlação. Esta é a questão. Assim, testamos os métodos de co-estimativa para vários conjuntos de dados apresentando diferentes graus de correlação. Na verdade, esses conjuntos de dados foram gerados em computador baseado em algoritmos de transformação de dados. Cinco valores de correlação foram considerados neste estudo: 0,993, 0,870, 0,752, 0,588 e 0,461. A cokrigagem colocalizada foi o melhor método entre todos testados. Este método tem um filtro interno que é aplicado no cálculo do peso da variável secundária, que por sua vez depende do coeficiente de correlação. De fato, quanto maior o coeficiente de correlação, maior é o peso da variável secundária. Então isso significa que este método funciona mesmo quando o coeficiente de correlação entre a variável primária e a variável secundária é baixo. Este é o resultado mais impressionante desta pesquisa. / This master dissertation presents the results of a survey into co-estimation methods commonly used in geostatistics. These methods are ordinary cokriging, collocated cokriging and kriging with an external drift. Besides that ordinary kriging was considered just to illustrate how it does work when the primary variable is poorly sampled. As we know co-estimation methods depend on a secondary variable sampled over the estimation domain. Moreover, this secondary variable should present linear correlation with the main variable or primary variable. Usually the primary variable is poorly sampled whereas the secondary variable is known over the estimation domain. For instance in oil exploration the primary variable is porosity as measured on rock samples gathered from drill holes and the secondary variable is seismic amplitude derived from processing seismic reflection data. It is important to mention that primary and secondary variables must present some degree of correlation. However, we do not know how they work depending on the correlation coefficient. That is the question. Thus, we have tested co-estimation methods for several data sets presenting different degrees of correlation. Actually, these data sets were generated in computer based on some data transform algorithms. Five correlation values have been considered in this study: 0.993; 0.870; 0.752; 0.588 and 0.461. Collocated simple cokriging was the best method among all tested. This method has an internal filter applied to compute the weight for the secondary variable, which in its turn depends on the correlation coefficient. In fact, the greater the correlation coefficient the greater the weight of secondary variable is. Then it means this method works even when the correlation coefficient between primary and secondary variables is low. This is the most impressive result that came out from this research.

Esta dissertação de mestrado apresenta os resultados de uma investigação sobre os métodos de co-estimativa comumente utilizados em geoestatística. Estes métodos são: cokrigagem ordinária; cokrigagem colocalizada e krigagem com deriva externa. Além disso, a krigagem ordinária foi considerada apenas a título de ilustração como esse método trabalha quando a variável primária estiver pobremente amostrada. Como sabemos, os métodos de co-estimativa dependem de uma variável secundária amostrada sobre o domínio a ser estimado. Adicionalmente, esta variável deveria apresentar correlação linear com a variável principal ou variável primária. Geralmente, a variável primária é pobremente amostrada enquanto a variável secundária é conhecida sobre todo o domínio a ser estimado. Por exemplo, em exploração petrolífera, a variável primária é a porosidade medida em amostras de rocha retiradas de testemunhos e a variável secundária é a amplitude sísmica derivada de processamento de dados de reflexão sísmica. É importante mencionar que a variável primária e a variável secundária devem apresentar algum grau de correlação. Contudo, nós não sabemos como eles funcionam dependendo do grau de correlação. Esta é a questão. Assim, testamos os métodos de co-estimativa para vários conjuntos de dados apresentando diferentes graus de correlação. Na verdade, esses conjuntos de dados foram gerados em computador baseado em algoritmos de transformação de dados. Cinco valores de correlação foram considerados neste estudo: 0,993, 0,870, 0,752, 0,588 e 0,461. A cokrigagem colocalizada foi o melhor método entre todos testados. Este método tem um filtro interno que é aplicado no cálculo do peso da variável secundária, que por sua vez depende do coeficiente de correlação. De fato, quanto maior o coeficiente de correlação, maior é o peso da variável secundária. Então isso significa que este método funciona mesmo quando o coeficiente de correlação entre a variável primária e a variável secundária é baixo. Este é o resultado mais impressionante desta pesquisa. / This master dissertation presents the results of a survey into co-estimation methods commonly used in geostatistics. These methods are ordinary cokriging, collocated cokriging and kriging with an external drift. Besides that ordinary kriging was considered just to illustrate how it does work when the primary variable is poorly sampled. As we know co-estimation methods depend on a secondary variable sampled over the estimation domain. Moreover, this secondary variable should present linear correlation with the main variable or primary variable. Usually the primary variable is poorly sampled whereas the secondary variable is known over the estimation domain. For instance in oil exploration the primary variable is porosity as measured on rock samples gathered from drill holes and the secondary variable is seismic amplitude derived from processing seismic reflection data. It is important to mention that primary and secondary variables must present some degree of correlation. However, we do not know how they work depending on the correlation coefficient. That is the question. Thus, we have tested co-estimation methods for several data sets presenting different degrees of correlation. Actually, these data sets were generated in computer based on some data transform algorithms. Five correlation values have been considered in this study: 0.993; 0.870; 0.752; 0.588 and 0.461. Collocated simple cokriging was the best method among all tested. This method has an internal filter applied to compute the weight for the secondary variable, which in its turn depends on the correlation coefficient. In fact, the greater the correlation coefficient the greater the weight of secondary variable is. Then it means this method works even when the correlation coefficient between primary and secondary variables is low. This is the most impressive result that came out from this research.

Les Sicydiinae amphidromes constituent une part importante des peuplements piscicoles insulaires de la région Indo-Pacifique et sont vulnérables à de nombreuses pressions anthropiques (i.e. pêcherie, dégradation et fragmentation des habitats). La reproduction a lieu en eau douce, puis les jeunes dévalent en mer où ils débutent leur croissance pendant quelques mois avant de coloniser les rivières. L’objectif est d’acquérir des connaissances sur les traits de vie de S. lagocephalus (cosmopolite) et de C. acutipinnis (endémique). Les travaux de terrain démontrent que le choix de l’habitat quotidien est fortement lié aux interactions sociales, alors que l’habitat de fraie montre une forte sélection pour des conditions morphodynamiques favorisant l’oxygénation des oeufs. Les mâles sélectionnent des sites de ponte et gardent les oeufs. L’étude expérimentale de la survie en eau douce confirme que tous les embryons libres possèdent la capacité à rejoindre la mer. L’analyse des traits de vie marins à partir des otolithes des post-larves révèle des variations saisonnières d’âge et de taille au recrutement, en lien avec la croissance et la température marine. L’examen histologique des ovaires permet de décrire les variations spatiales et temporelles de l’activité de reproduction chez les femelles en rivière et de déterminer la fécondité et la taille de première reproduction. Les variations inter et intra-spécifiques des traits de vie sontcomparées en lien avec la répartition géographique des deux espèces. Ces travaux permettent d’identifier des perspectives concrètes dans le domaine de la gestion et de la conservation sur la base des caractéristiques de la stratégie amphidrome. / Amphidromous Sicydiinae are particularly widespread among fish freshwater assemblages of the Indo-Pacific region and are vulnerable to anthropogenic pressures (i.e. fishery, degradation and fragmentation of habitats). Spawning and hatching happen in freshwater, then offspring drift downstream to the sea where they begin their growth for a few months before recruiting in the rivers. This study aims at acquire knowledge about life traits of S. lagocephalus (cosmopolite) and C. acutipinnis (endemic). Field sampling shows that the usual habitat choice is related to social interactions, whereasspawning habitat shows a strong selection for morphodynamic conditions which favor eggs oxygenation. Males select spawning sites and care for the eggs. The experimental study of freshwater survival confirms that free embryos survival and swimming capacities are enough to drift to the ocean. Marine life history analysis, based on postlarvae otoliths examination, reveals a seasonal variation of both age and size-atrecruitment related to the larval growth rate and the sea temperature. Histological examination of ovaries is used to describe the spatial and temporal variation of reproductive activity of mature females in the rivers, and to determine fecundity and size at first reproduction. Inter and intra-specific variations of life history traits are compared in relation to the respective geographical distribution of both species. This study identifies concrete prospects for management and conservation based on the features of amphidromous life history strategy.

無人飛行載具(Unmanned Aerial Vehicle, UAV)於要求精度之圖資測製應用時，因飛行高度較低並可在雲下飛行取像，與大型載具相比可更機動性獲取空間解析度較高之影像，雖無法如大型載具酬載大像幅感測器供大區域圖資製作，但於小區域之圖資更新卻相當適合。但一般UAV因酬載重量限制，僅可酬載體積小且重量輕之感測器，如非量測型相機及低精度定位定向系統，即AHRS系統。因此，本研究嘗試在UAV上酬載Trimble BD970 GNSS OEM GPS接收模組，此GPS接收模組體積小且重量輕可安置於UAV上，並透過VBS-RTK GPS定位技術獲取UAV精確飛行軌跡資訊，再經時間內插相機曝光瞬時的GPS資訊供空中控制使用，輔助UAV影像空中三角測量(簡稱空三)平差，以降低地面控制點需求。 但欲引入GPS觀測量供空中控制使用必須考量GPS天線與相機投影中心偏移量之問題，但因UAV所酬載之非量測型相機，將造成此偏移量不易透過地面測量方式測得，於本研究將於空三平差時使用線性漂移參數克服此偏移量無法量測之問題；此外，UAV所酬載之非量測型相機，相機參數乃透過地面近景攝影測量以自率光束法平差方式率定所得，但率定所得相機參數無法完全描述相機在航拍取像時的情況，故本研究於空三平差將採用自率光束法克服相機參數率定不完全之問題。實驗中，首先確定GPS模組BD970在VBS-RTK GPS定位技術下在地面高速移動時可獲得高精度的定位成果；接續驗證線性漂移參數及自率光束法平差於此研究的適用性；最後亦探討不同地面控制點配置及來源對空三平差之精度探討，並提出1/5000基本圖圖資測製精度要求下，VBS-RTK GPS輔助UAV影像自率光束法空三平差的地面控制點最適配置。 / UAV(Unmanned Aerial Vehicle) is currently used in civil purpose such as mapping and disaster monitoring. One of UAV advantages is to collect images with high resolution for mapping demand. However, due to payload limitations of UAV, it is difficult to mount metric aerial camera and precise POS(Positioning and Orientation System) device. Instead, only the non-metric camera and the low accurate AHRS (Attitude and Heading Reference System) can be installed. For mapping demands, Trimble BD970 GNSS OEM board will be carried on the UAV to collect the high accurate flying trajectory as control information for AT (aerial triangulation) by VBS-RTK(Virtual Base Station - Real Time Kinematic) GPS technique. Meanwhile self-calibration bundle adjustment will be employed for AT(Aerial Triangulation) to overcome the imperfect calibration of non-metric camera by the close-range photogrammetric approach. The precise offset between image perspective center and GPS antenna center, called GPS antenna-camera offset, is hard to measure in centimenter level by terrestrial measurement approach. Therefore the drift parameters will be utilized to solve the problem of GPS antenna-camera offset while performing bundle adjustment with self-calibration for AT of UAV images. In the experiments of this study, the height positioning accuracy of BD970 by VBS-RTK GPS approach at high speed movement will be proved firstly. Then the adaptability of drift parameters and self-calibration for GPS supported AT of UAV images will be verified. Finally, the accuracy of AT by using different control information will be analized and appropriate configuration of GCPs(Ground Control Points) for VBS-RTK GPS supported self-calibration bundle adjustment for AT of UAV images will be proposed under the mapping demand with the scale of 1 : 5000.

Cable-actuated manipulators (or 'cable robots') constitute a relatively new classification of robots which use motors, located at fixed remote locations, to manipulate an end-effector by extending or retracting cables. These manipulators possess a number of unique properties which make them proficient with tasks involving high payloads, large workspaces, and dangerous or contaminated environments. However, a number of challenges exist which have limited the mainstream emergence of cable robots. This thesis addresses two of the most important of these issues-- workspace analysis and disturbance compensation. Workspace issues are particularly important, as many large-scale applications require the end-effector to operate in regions of a particular shape, and to exert certain minimum forces throughout those regions. The 'Force-Feasible Workspace' represents the set of end-effector positions, for a given robot design, for which the robot can exert a set of required forces on its environment. This can be considered as the robot's 'usable' workspace, and an analysis of this workspace shape for point-mass cable robots is therefore presented to facilitate optimal cable robot design. Numerical simulation results are also presented to validate the analytical results, and to aid visualization of certain complex workspace shapes. Some cable robot applications may require mounting motors to moving bases (i.e. mobile robots) or other surfaces which are subject to disturbances (i.e. helicopters or crane arms). Such disturbances can propagate to the end-effector and cause undesired motion, so the rejection of motor mount disturbances is also of interest. This thesis presents a strategy for measuring these disturbances and compensating for them. General approaches and implementation issues are explored qualitatively with a simple one-degree-of-freedom prototype (including a strategy for mitigating accelerometer drift), and quantitative simulation results are presented as a proof of concept.

This thesis, within the subfield of computer science known as computer vision, deals with the use of scale-space analysis in early low-level processing of visual information. The main contributions comprise the following five subjects: The formulation of a scale-space theory for discrete signals. Previously, the scale-space concept has been expressed for continuous signals only. We propose that the canonical way to construct a scale-space for discrete signals is by convolution with a kernel called the discrete analogue of the Gaussian kernel, or equivalently by solving a semi-discretized version of the diffusion equation. Both the one-dimensional and two-dimensional cases are covered. An extensive analysis of discrete smoothing kernels is carried out for one-dimensional signals and the discrete scale-space properties of the most common discretizations to the continuous theory are analysed. A representation, called the scale-space primal sketch, which gives a formal description of the hierarchical relations between structures at different levels of scale. It is aimed at making information in the scale-space representation explicit. We give a theory for its construction and an algorithm for computing it. A theory for extracting significant image structures and determining the scales of these structures from this representation in a solely bottom-up data-driven way. Examples demonstrating how such qualitative information extracted from the scale-space primal sketch can be used for guiding and simplifying other early visual processes. Applications are given to edge detection, histogram analysis and classification based on local features. Among other possible applications one can mention perceptual grouping, texture analysis, stereo matching, model matching and motion. A detailed theoretical analysis of the evolution properties of critical points and blobs in scale-space, comprising drift velocity estimates under scale-space smoothing, a classification of the possible types of generic events at bifurcation situations and estimates of how the number of local extrema in a signal can be expected to decrease as function of the scale parameter. For two-dimensional signals the generic bifurcation events are annihilations and creations of extremum-saddle point pairs. Interpreted in terms of blobs, these transitions correspond to annihilations, merges, splits and creations. Experiments on different types of real imagery demonstrate that the proposed theory gives perceptually intuitive results. / <p>QC 20120119</p>

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De uppgifter som revisorn presenterar i sin revisionsberättelse bör intressenter och företag ha förtroende för. Revisorn ska vara en oberoende länk mellan intressenter och företag. Läsaren förväntar sig finna eventuella ekonomiska problem i årsredovisningen. Detta är dock inte alltid fallet. Det är viktigt att revisorerna kan göra en pålitlig bedömning över företagets möjligheter till fortsatt drift. Beslut om going concern-varning måste grunda sig på oberoende och god kunskap om företagets situation. En felaktig going concern-varning kan orsaka problem och intäktsbortfall för både företaget och revisionsbyrån. Intressenterna kan förlora förtroendet för företaget och företaget kan i sin tur byta revisor. Studien fokuserar på huruvida revisorerna kan vara sparsamma med att utge going concern-varning för att inte riskera att förlora företaget som klient och därmed förlora revisionsintäkter. Därför undersöker studien om det finns ett samband mellan förlorade revisionsarvoden och utfärdandet av en första going concern-varning bland svenska företag. Studien vill också visa ifall en going concern- varning ökar sannolikheten för konkurs den s.k. självuppfyllande profetian. Ett bidrag till tidigare forskning är att studien beaktar revisionsuppdragets längd i förhållande till going concern-varning. Från databasen Affärsdata har 432 företag selekterats ut från bokslutsåret 2009. Av dessa hade 216 erhållit en going concern- varning. Denna testgrupp har sedan jämförts med en kontrollgrupp med samma antal som varit finansiellt stressade men inte erhållit någon varning. Studien har använt SPSS som statistiskt program för att kunna göra önskade beräkningar. Studiens resultat visar at det finns ett samband mellan en första going concern-varning och revisorbyte. Studien visar också att längden på revisionsuppdraget påverkar benägenheten att ge en going concern-varning. Däremot finner undersökningen inte något belägg för den s.k. självuppfyllande profetian. / The information that the auditor provides in their audit report should be valid in the eyes of the stakeholders of the company. The auditor should be the independent link between the company and its stakeholders. When reading the audit report, one expects to find all the possible economic problems identified in it, however this is not always the case. It is crucial that the audit of a company’s going concern is reliable. Decisions regarding going concern-modified opinions should be independent and be based on valid information regarding the company’s economic situation. One faulty going concern-modified opinion can set off a whole range of issues and revenue loss for both the company and the audit firm. Consequently stakeholders can lose their trust in the company resulting in a change of audit firm. This thesis is focused on whether or not auditors might be reluctant to hand out going concern-modified opinions in fear of losing a client and the revenue associated with it. Therefore, the thesis investigates whether or not there is a relationship between lost revenue and the first instance of issuing a going concern-modified opinion for Swedish companies. This thesis is also investigating whether the issuance of a going concern-modified opinion will increase the possibility of the company going bankrupt, the so-called self-fulfilling prophecy. A contribution to the previous research regarding the going concern issue is the consideration of audit tenure. We have used 432 companies with fiscal year 2009 extracted from the database Affärsdata. Out of this selection, 216 had been issued a going concern-modified opinion. This test group is then compared to the control group with the same number of companies that were identified as financially distressed but without receiving a going concern- modified opinion. The thesis has used the statistical program SPSS to complete the calculations needed to complete the analysis. The result shows a positive relationship between the first going concern-modified opinion and the change of audit firms. The period of time the auditing requires also effects the predisposition to issue a going concern-modified opinion. However the study was unable to find any statistical evidence for the so-called self-fulfilling prophecy.

The connection between water and human wellbeing is increasingly causing concern about the implications of water scarcity on poverty. The primary fear is that water scarcity may not only worsen poverty, but may also undermine efforts to alleviate poverty and food insecurity. A review of literature revealed that the relationship between water scarcity and poverty is a complex one, with water scarcity being both a cause and consequence of poverty. Furthermore, water scarcity is multidimensional, which makes it difficult to define, while it can also vary considerably, both temporally and spatially. Finally, the relationship between water scarcity and poverty is a difficult one to quantify. Within the context of water scarcity, indicators are viewed by many development analysts as appropriate tools for informing and orienting policy-making, for comparing situations and for measuring performance. However, simplistic traditional indicators cannot capture the complexity of the water-poverty link; hence a proliferation of more sophisticated indicators and indices since the early 1990s. The Water Poverty Index (WPI), one of these new indices, assesses water scarcity holistically. Water poverty derives from the conceptualisation of this index which relates dimensions of poverty to access to water for domestic and productive use. However, the WPI has not been applied extensively at meso-catchment scale, the scale at which water resources managers operate. In South Africa, the Thukela Catchment -in the province of KwaZulu-Natal presents a unique opportunity to assess the WPI at this scale. The Thukela is a diverse catchment with respect to physiography, climate and (by extension) natural vegetation, land use, demography, culture and economy. While parts of the catchment are suitable for intensive agricultural production and others are thriving economic centres, a large percentage of the population in the catchment lives in poverty in high risk ecosystems, with their vulnerability exacerbated by policies of the erstwhile apartheid government. Many rural communities, a high percentage of which occupy these naturally harsh areas, have low skills levels, with a high proportion of unemployed people, low or no income and low services delivery. Infrastructural development, which relates to municipal service delivery, is often made prohibitively expensive by the rugged terrain in which many people live. As in other catchments in South Africa, the Thukela is affected by policies and initiatives aimed at accomplishing the objectives of post-1994 legislation such as the South Africa Constitution and the National Water Act. The potential of the WPI to assess the impacts of these initiatives on human wellbeing and to inform decision .making in the Thukela catchment was investigated. An analysis of a 46 year long series of monthly summations of daily values of streamflows output by the ACRU agrohydrological simulation model has shown that the Thukela, in its entirety , is a water-rich catchment. The reliability of the streamflows, which has implications for communities who collect water directly from 1 streams, is high along main channels but can be considerably less along low order tributaries of the main streams. The flow reliability along the small tributaries is less in winter than in summer. A high percentage of the catchment's population, in addition to being poor and not having access to municipal services, live near, and rely on, the small tributaries for their water supplies. Admittedly, this analysis addresses only one dimension of water poverty, viz. physical water shortage. Nevertheless, the study revealed that despite the Thukela's being a water-rich catchment, many communities are still water stressed. A more holistic characterisation of the water scarcity situation in the Thukela catchment was achieved using the WPI. A review of possible information sources for computing the WPI in South Africa found that many monitoring programmes, information systems and databases are either in existence and are active, or being restructured, or are under different stages of development. If and when they are all fully functional , they should be able to support national assessments of the WPI at meso-scale without the need to collect additional information. A combination of information from some of the active databases and secondary data from other local studies was used to compute the WPI in the Thukela catchment. The assessment uncovered the following: • There is an apparent association between water poverty and socio-economic disadvantage in the Thukela catchment. • There was an improvement in the water poverty situation in most parts of the Thukela catchment between 1996 and 2001, although the degree of improvement varied from subcatchment to subcatchment. Climate change, if it manifests itself by higher temperatures and reduced rainfall, will most likely worsen water poverty throughout the Thukela catchment, with the subcatchments in which many of the poor communities are located being more likely to experience the most severe impacts as the coping capacities of those communities are already strained under current climatic conditions. The findings of this study illustrate the potential of WPI as a tool for informing decision making and policy evaluation at the meso-catchment scale at which many water-related decisions are made. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2006.