The work deals with two problems of mass rapid transit system operation: The development of flexible timetables and the realisation of flexible timetables. In both cases, genetic algorithms are used. In the process of (flexible) timetabling in suburban railways, a transport offer perfectly adapted to demand is searched for (temporal and spatial adaptation of demand as well as adaptation of capacity of the trains). After determination of the number of train runs per line and hour and their capacity, optimal departure times have to be found (with a precision of a minute down to 10 s), which fulfil criterias of the passengers (short waiting times) as well as of the operator (small number of vehicles needed). Two different codings for use with genetic algorithms have therefore been developed. They are tested on several case studies of the Dresden suburban railway network, assuming different degrees of flexibilisation. In the process of realising a flexible timetable, transitions between train headways as well as running time and dwell time reserves (margins in the order of a few seconds) are slightly modified in order to coordinate braking and accelerating trains and thereby reduce energy costs of a system of trains. Genetic algorithms can be applied for this problem as well, the proposed methods are tested on several case studies (S-Bahn Berlin, Metro Lille). / Die Arbeit behandelt zwei Probleme der Betriebsplanung von Stadtschnellbahnen: Die Erstellung flexibler Fahrpläne und die Umsetzung flexibler Fahrpläne. In beiden Fällen werden zur Lösung Genetische Algorithmen verwendet. Bei der Ermittlung flexibler Fahrpläne von S-Bahnen wird ein bestmöglich an die Verkehrsnachfrage angepasstes Verkehrsangebot gesucht (zeitlich, räumlich und bezüglich der Kapazität der einzelnen Züge angepasst). Nach stundenfeiner Festlegung der Fahrtenhäufigkeiten und Kapazitäten der einzelnen, sich überlagernden Linien werden deren Abfahrtszeiten gesucht (mit einer Genauigkeit von Minuten bis etwa 10 s), so dass sowohl die Wünsche der Fahrgäste nach gleichmäßigen Zugfolgezeiten als auch Betreiberwünsche (geringe Fahrzeuganzahl) erfüllt werden. Hierzu werden zwei verschiedene Kodierungen für die Verwendung mit Genetischen Algorithmen vorgestellt und das geschaffene Verfahren an verschiedenen Flexibilisierungsszenarien für die S-Bahn Dresden erprobt. Bei der Umsetzung flexibler Fahrpläne, die sich im Bereich weniger Sekunden abspielt, werden Übergänge zwischen Zugfolgezeiten, Fahr- und Haltezeitreserven geringfügig modifiziert, so dass durch bestmögliche Koordination von Anfahr- und Bremsvorgängen eines Systems von Zügen die Energiekosten minimal werden. Methodisch werden wiederum Genetische Algorithmen verwendet, die Erprobung des Verfahrens erfolgt anhand von Linien der S-Bahn Berlin und der Metro in Lille.

Increased use of variable energy and integration of electricity markets in the European Union have led to new challenges when balancing supply and demand in the grid. Load management is a possible way to manage these challenges by adjusting electricity consumption in order to balance the power system. Household appliances can be used for this purpose, for example by providing automatic frequency control. The aim of this master thesis is to investigate the potential of load management from private households and to examine how the power system is affected by a more flexible electricity consumption. The thesis focuses on fridges as automatic frequency control reserves and the ability of fridges to balance the power system. Attributes such as capacity, activation time, persistence and the effect of load reconnection has been modelled in Simulink, Matlab. Complementary interviews with actors from the electricity industry have been done to summarize their insights on demand response. The results indicate that fridges can be used as a part of the automatic frequency controlled reserve FCR-N, based on assumptions made in this study. However, current requirements imposed on balancing resources are not fully met by the fridges. In order for household appliances to provide the needed flexibility, some requirements might need to be rephrased. The results also show that the capacity for providing balancing services differs for positive and negative imbalances, as consumption can be reduced with 30 MW and increased with 66 MW. When controlling the fridges by moving the reference temperature, there is a risk that the appliances will synchronize with each other, i.e. reconnect or disconnect at the same time, resulting in frequency oscillations. It is therefore important that load management is designed to avoid this kind of behavior.

Increased use of variable energy and integration of electricity markets in the European Union have led to new challenges when balancing supply and demand in the grid. Load management is a possible way to manage these challenges by adjusting electricity consumption in order to balance the power system. Household appliances can be used for this purpose, for example by providing automatic frequency control. The aim of this master thesis is to investigate the potential of load management from private households and to examine how the power system is affected by a more flexible electricity consumption. The thesis focuses on fridges as automatic frequency control reserves and the ability of fridges to balance the power system. Attributes such as capacity, activation time, persistence and the effect of load reconnection has been modelled in Simulink, Matlab. Complementary interviews with actors from the electricity industry have been done to summarize their insights on demand response. The results indicate that fridges can be used as a part of the automatic frequency controlled reserve FCR-N, based on assumptions made in this study. However, current requirements imposed on balancing resources are not fully met by the fridges. In order for household appliances to provide the needed flexibility, some requirements might need to be rephrased. The results also show that the capacity for providing balancing services differs for positive and negative imbalances, as consumption can be reduced with 30 MW and increased with 66 MW. When controlling the fridges by moving the reference temperature, there is a risk that the appliances will synchronize with each other, i.e. reconnect or disconnect at the same time, resulting in frequency oscillations. It is therefore important that load management is designed to avoid this kind of behavior.

Parks and protected areas are crucial for the health of the biosphere and long-term sustainability of the planet. However challenges these areas face include: there are simply not enough of them, the existing ones are often too small and fragmented, and there is not always public support for them. Regional parks are specific types of protected areas that can help contribute to conservation and sustainability. The effectiveness of protected areas for conservation can be enhanced through a variety of strategies such as “biosphere reserves”. This research looks at stakeholder perceptions regarding potential benefits of the Mount Arrowsmith Massif Regional Park and the importance of the Mount Arrowsmith Biosphere Reserve Operating Framework. This study has contributed to the larger Protected Areas and Poverty Reduction (PAPR) research initiative as it discusses the flow of costs and benefits from protected areas and alternate forms of protected area governance.

Thesis (M.Tech.: Information Technology)-Durban Institute of Technology, 2005 iii, iii, 85 leaves / Throughout Africa, growing human populations and resulting loss of wildlife habitat is a critical issue for most animal species. It is more and more common for privately owned small or medium sized farms to reintroduce wildlife on their land and such protected areas are fast becoming the only refuges available to wild animals. However a comprehensive understanding of the complex ecological processes taking place is vital for the effective management of restricted areas and the conservation of biodiversity. Due to the enormous complexity of an ecological system and the long periods of the related dynamics, it is very difficult to analyse the interaction between animals and plant populations without suitable computer models. In this thesis, the dynamics between elephant and trees (a major food source) are considered using computer simulations.

This thesis seeks to contribute to the improved understanding of social systems analysis in management effectiveness research on protected areas. It develops and applies propositions for incorporating the analysis of social systems into management effectiveness research. The propositions are designed as theoretical constructs which represent some aspects of social reality in protected area management. They signify an organized way of thinking about the social domain of protected area management. It is argued that an analysis of management effectiveness must recognize the need to take into account the inherent interactive nature of the connections among three variables, relationships, learning and demands. It is suggested that the three variables do not exist in isolation, but are interconnected and exert influence on each other. The interactions among the variables provide this study with a conceptual structure for analyzing the social domain of protected area management. The thesis conceives the management of relationships as a behavioral process in which protected area management agencies influence the decisions and actions of other parties, and vice versa, over a period of time in order to advance shared interests. The effectiveness of relationship management depends on integrated learning, a collective process of managing information in a timely manner so as to enhance the responsiveness of social actors involved with protected areas. Demand management is viewed as a social process in which protected area management agencies develop timely and defensible responses to current and emerging demands from stakeholders. The management of demands is expressed through relationship management and integrated learning. Important in this context is the capability of social actors to cope with complexity, change and surprises. The thesis should be seen as a theoretical premise that focuses on the learning competence of social actors by aligning and fostering their ability to respond timely to the ever-changing demands on protected areas through the effective management of relationships. It should be viewed as making a contribution to the move in protected area management towards developing learning organizations and institutions through a systems approach. This should be interpreted as enhancing learning about the human dimensions of protected area management. And more specifically, effective learning generates timely responses in the management of demands and relationships. The implications of failure to respond quickly enough are epitomized in a number of South African examples such as rivers that stop flowing and conflicts over resource use. The thesis makes a contribution to management effectiveness research by examining in some important ways why research should not be determined solely by biophysical components, but should be extended to the broader social issues that define the nature and quality of management. It is argued that a deep appreciation of management effectiveness requires an understanding of relationships, learning and demands to provide a foundation for systemic social analyses. The thesis illustrates why a behavioral approach to relationships theory provides a foundation for resilient social relationships in collaborative processes. It shows why the establishment and maintenance of an integrated learning system take place in a complex context which links elements of governance learning and management learning. It also evinces why protected area management agencies have to incorporate mental models into adaptive management of demands. These insights imply that the opportunities for effective protected area management are largely contingent on systemic insights into the underlying social structures and processes responsible for emergent problems. By exposing the insights, research on management effectiveness is poised to take new direction. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2007.

This study was designed to capture the complexity of man-to-forest relationships in the endangered, world-renowned tropical rain forests of the Congo Basin in Africa. Their biological complexity and integrity have been challenged by human development and new knowledge is urgently needed to save these forests and the people dependent on them. The scope of the study was enormous because of the complexity of the resource, the diversity of forest-dependent people and actors. The major benefit of this research was in accessing and exposing new and quantitative information in remote settlements of the region by applying innovative methodologies and analytical techniques. These included: 1. The definition of forest-dependency based on detailed annual inventories of sources of households’ incomes, their statistical ranking and interpretation with logistic regressions, and the Kuznets ratio and Gini coefficients as introduced by the World Bank; 2. critical appraisal of the international parks in the region based on auto-financing principles and tested with contingent valuation and tax maximization techniques, such as Laffer’s curves, and leading to the development of new conservation models of financial self-sufficiency and a new formula for practical park management; 3. the critique of poaching by explaining and exposing food insecurities, especially deficient supplies of animal protein and associated malnutrition among the rural poor; 4. assessment of housing inadequacy among forest dwellers and its impact on forest regeneration and resources; 5. clarification of the impacts of timber logging by accessing detailed unpublished information from timber companies; 6. the introduction of survey-based valuation techniques as essential prerequisites to policy formulation and the sustainable management of forests; 7. proposing a flow chart that embraced the resources and stakeholders through the flow of market values and services for further exploration. Contrary to traditional beliefs; the results showed that both poor and wealthy households are equally dependent on forest resources for their livelihoods with no significant difference in consumed forest products between the 25% higher income earners and the 25% lower income households. Forests contribute over 57% of wage income in the region and forest-derived income is of a higher total value than any other source, including agriculture. Among forest foods, wild fruit and bushmeat are by far the most important. Therefore, the clearing of forests for agriculture or instituting conservation policies that completely keep local people away from forests will result in constrained access to resources of immense importance to local livelihoods. However, the findings contradict the commonly propagated views that timber harvesting in the region is directly responsible for deforestation, the loss of forest structure and biodiversity. It was shown that the harvesting of saplings and poles for housing may endanger forest regeneration and species composition of forests neighbouring the villages. The desired financing of national parks should be through internally generated revenues, requiring deliberate investments in facilities and infrastructure. The necessity to satisfy the basic needs of the forest-dependent people remains urgent. The complexity of man-to-forest relationships is beyond one study and needs to be further expanded on, in our quest to sustainable forest management based on participatory principles. Such management needs to provide for and be supported by various stakeholders including the local communities, state agencies, donors, NGOs, and commercial conglomerates. Moreover, the need to understand forest values beyond market principles is required in order to translate the concept of sustainable forest management from a theoretical concept in the Congo Basin to one that can reduce conflicts, deforestation, poverty and famine.

Imperfect information on aspects of biodiversity conservation will constrain the extent to which tourists’ preferences for biodiversity conservation are revealed in game reserve (GR) tariffs, reducing the incentive for tourism businesses to invest in biodiversity conservation. Accreditation is an institutional approach to addressing the issue of imperfect information on biodiversity conservation. In this study, Choice Experiments (CE) and the Contingent Valuation Method (CVM) are used to estimate tourist’s willingness-to-pay (WTP) to visit biodiversity conservation accredited terrestrial nature-based tourism (NBT) destinations in selected areas of South Africa (SA). A survey of 97 domestic tourists and 96 foreign tourists was conducted at 16 private and public GR camps in north-eastern KwaZulu-Natal (NEKZN) and Mpumalanga/Limpopo Provinces (MP/LP) during October and November 2004. The survey captured socio-economic data to be used in discriminating between market segments, eighteen hypothetical CE questions and a CVM question. Analyses comparing the preferences of domestic tourists from foreign tourists, tourists visiting NEKZN from tourists visiting MP/LP and tourists visiting private GRs from tourists visiting public GRs were performed. In addition, Hierarchical Cluster Analysis (HCA) was used to identify groups of tourists with similar preferences. Respondents are grouped into three market segments according to their revealed preferences using HCA. Linear Discriminant Analysis (LDA) was used to discriminate the three groups based on socio-economic characteristics. These groups were named “Conservation Vacationers”, “Incidental Sightseers” and “Big 5 Brigade” based on socioeconomic characteristics unique to each group. The region (NEKZN or MP/LP), level of education and itinerary (independent travellers or part of tour group) were the most powerful in discriminating “Big 5 Brigade” from the other two groups in the first function. The second function primarily discriminates Conservation Vacationers from Incidental Sightseers based on membership to a wildlife society, gender and education. Results of the CE and CVM studies respectively, indicate that, overall, respondents were willing to pay premiums of R114.41 and R87.67 per person per night (all premiums are presented as per person per night, unless otherwise stated) to stay at a GR accredited with having a high standard of biodiversity conservation. Foreign tourists were, on average, willing to pay the highest premium of R136.35 for biodiversity conservation accreditation, while tourists visiting private GRs were, on average, willing to pay the lowest premium of R 96.42. A further three market segments were identified using HCA. The average WTP estimates for biodiversity conservation accreditation for Groups 1(Conservation Vacationer), 2(Incidental Sightseer) and 3(Big 5 Brigade), identified by HCA were R171.41, R66.15 and R14.94, respectively. On average, respondents in all groups, game-viewing quality was most highly valued, followed by the level of congestion. Results of this study may be useful to NBT operators and managers in developing marketing strategies targeting specific market segments. Analysis of the results by market segments indicates that CE may be a more reliable technique than CVM. Further research on the costs and benefits of biodiversity conservation accreditation is necessary to predict the extent to which NBT businesses are likely to adopt biodiversity conservation accreditation. / Thesis (M.Agric.Man.)-University of KwaZulu-Natal, Pietermaritzburg, 2007.

Cette thèse comprend trois essais en économie de l’environnement et des ressources naturelles sous incertitude. Le premier essai propose un modèle de jeu différentiel qui analyse la pollution globale à travers la quête à l’hégémonie politique entre pays. Le second essai utilise des données boursières pour estimer une version stochastique de la règle de Hotelling et ainsi inférer sur le rôle des ressources naturelles non renouvelables dans la diversification du risque. Le troisième essai montre comment la prise en compte des perspectives futures modifie la règle de Hotelling dans un contexte de diversification du risque. / My thesis is composed of three essays on environmental and natural resource economics under uncertainty. The first essay proposes a differential game analysis of the quest for hegemony among countries as a generator of global pollution. The second essay uses stock market data on market capitalization to estimate a stochastic version of the Hotelling rule of exhaustible resource exploitation and uses it to infer on the riskiness of investment in nonrenewable resources and its effect on the resource price paths. The third essay shows how uncertainty about future prospects modifies the Hotelling rule in a context of risk diversification.

This Research investigates the potential impacts that free-ranging lions have within a small (<100 000 hectare), enclosed protected area, and it also investigates the subsequent challenges to the managers of areas such as these. A comprehensive literature review reveals that the smaller the protected area, the more intensively it needs to be managed via active adaptive management, because perimeter fences do not allow for immigration and emigration. The consequences of this are over-population; inbreeding depression; the decline of prey and other predator species; conflict with neighbouring communities as a result of break-outs; and, in some cases, the spreading of intra- and interspecies disease. Lions are very proficient breeders and, in all cases investigated, reserves exceeded their local carrying capacity within a relatively short period of time. A range of management interventions can potentially achieve short- and/or long-term reserve objectives. These interventions include relocation, contraception, hunting and artificial takeovers. These interventions are described in terms of the preparation required, the biological consequences and the sociological influences. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2007.