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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
261

Dynamics of Coupled Human-Water Infrastructure Systems Under Water Main Breaks and Water-Rates Increase Events

Hamed Zamenian (8781884) 30 April 2020 (has links)
<p>The aging water infrastructure system in the United States has posed considerable hindrance to policy-makers as they seek to provide safe, reliable, and clean drinking water for communities. The deterioration of the physical water infrastructure negatively affects the economics of water utilities and can lead to increases in water rates for consumers, so that utilities can recover the financial losses. However, the dynamics emerging from the interactions among changes in water service reliability, water-rates, consumer behavior (with respect to water consumption and willingness to support water-rate changes in response to changes in water rates, and water utility economics, are still unknown factors in the management of water infrastructure systems. </p> <p>The overarching objective of this dissertation is the creation and demonstration of the dynamics of coupled human and water infrastructure systems under conditions of water main breaks and water-rate increases. First, using water-main break data for a 21-year period from two U.S. cities in the Great Lakes region, the dissertation demonstrates a methodology to estimate the system-wide monthly frequency of water main breaks as a function of a number of explanatory variables. Using a random-parameters negative-binomial approach, the statistical estimations show that pipe diameters, average pipe age, distribution of pipe age, pipe material, time of year, and mean monthly temperature all have a significant impact on monthly water main break frequencies. The results can assist asset managers in quantifying the effect of factors may have on the likelihood of water main breaks, as well as in making cost-effective decisions regarding pipe renewal.</p> <p>Next, by incorporating qualitative survey data and using quantitative econometric methods, consumer behaviors in responses to the water-rate increases, and based on perceptions of water service reliability and quality in a Midwestern U.S. city was evaluated. Using a multivariate binary probit approach, the results provide insights as to how individuals are likely to respond to water-rate increases based on the reliability of current water services and the quality of the supplied water. The outputs of the econometric enable utility managers to better understand the behavior of consumers under different rate conditions and help water utilities in their long-term and short-term financial analyses.</p> <p>Finally, the aforementioned two components are integrated into the interdependency analysis to evaluate the interactive effects of features of the physical water infrastructure (pipeline characteristics, water and associated energy losses, and the revenue loss for water utilities) and the behavior of stakeholders (water utilities and consumers). The developed hybrid system dynamics and agent-based model examines interdependencies between the physical water infrastructure, the water utility, and the water consumers to explore possible emergent behavior patterns of water users during water rate increases over time. The model is demonstrated over the 2001–2010 period on a case study city with a large water distribution system that includes 4,000 miles of pipeline and nine water treatment plants serving a population of 863,000. This model was then verified and validated throughout the development of simulation models and included the following steps: 1) data validity, 2) conceptual model validity, 3) computerized model validity, and 4) operational validity. The results suggest the simulated behavior of the model was reasonable and the output of the simulation model regrading water main break frequency, amount of water and associated energy losses, generated revenue, and payoff periods for implementing proactive maintenance strategies had the accuracy required for the model’s intended purpose. </p> <p>The framework developed in this doctoral study can be applied to different size classifications of cities, as well as different classifications of utility companies (such as electricity and gas) by updating the parameters in the model to reflect the characteristics of the infrastructure system components. The distinctive methodological approach in this doctoral work could capture the emergent behaviors of human-water infrastructure interactions such as the impact of increasing water-rates on residential consumers, the impact of water price elasticity cascading into the water utility revenue, and the impact of residential consumers’ water consumption on water utility revenues. In conclusion, the results of this doctoral research can assist asset managers in understanding their systems, identify pathways for growing revenue through reducing non-revenue water and increasing water-rates, and implementing a proactive pipeline asset management program towards the provision for safe, reliable, and clean drinking water.</p>
262

Erweiterung des CRC-Karten-Konzeptes um Rollen

Hamann, Markus 07 September 2017 (has links)
Die rollenbasierte Modellierung ist ein aktueller Forschungszweig, welcher Verfahren für die Analyse und die Lehre benötigt. Zu diesem Zweck präsentiert die Arbeit eine Erweiterung des klassischen, objektorientierten CRC-Karten-Verfahrens um rollenbasierte Konzepte. Diese basiert auf grundlegenden Eigenschaften rollenbasierter Elemente, wie Rollen, Objekte und Kontexte, welche modular in das CRC-Karten- Verfahren eingebunden werden. Weiterhin soll anhand einer empirische Studie ermittelt werden, wie gut das rollenerweiterte R-CRC-Karten-Verfahren für die Aufgaben in Analyse und Lehre geeignet ist. Das R-CRC-Karten-Verfahren soll letztendlich eine effiziente Möglichkeit bieten, Problemstellungen rollenbasiert zu analysieren und rollenbasierte Konzepte in der Lehre zu vermitteln.
263

MobIS 2010 - Modellierung betrieblicher Informationssysteme, Modellgestütztes Management: 15.-17. September 2010 in Dresden, Germany

Esswein, Werner, Turowski, Klaus, Juhrisch, Martin January 2010 (has links)
This volume contains contribution form the refereed “MobIS 2010” main program and selected papers of its tracks. The conference on information systems modeling was held in Dresden September 15-17, 2010. The guiding theme for MobIS 2010 focused on modeling topics between model-based management and component and service engineering.:Vorwort..................................................................................................................7 Modellgestütztes Management Esswein Werner, Stark Jeannette, Schlieter Hannes The selection of modeling grammars...................................................................13 Trojahner Iris, Weller Jens, Fürstenau Bärbel, Esswein Werner Der Einfluss von Modellierungswerkzeugen auf Qualität und Quantität von Modellen – Eine empirische Untersuchung.........................................................29 Weller Jens, Helbig Michaela, Großmann Knut Eine Methode fu!r den praktischen Einsatz von Konfigurationsmanagement in verteilten Modellierungsprojekten.......................................................................47 Fengel Janina, Rebstock Michael Domänensemantik-orientierte Integration heterogener konzeptueller Modelle................................................................................................................63 Bögel Stephan, Esswein Werner Vertikale Modellintegration in Rahmenwerken – Evaluation von Integrationsansätzen und Untersuchung der Implementierbarkeit anhand eines Fallbeispiels.........................................................................................................79 Fellmann Michael, Hogrebe Frank, Thomas Oliver, Nüttgens Markus An ontology-driven approach to support semantic verification in business process modeling.................................................................................................99 Juhrisch Martin, Dietz Gunnar Context-based Modeling: Introducing a Novel Modeling Approach................111 Strecker Stefan, Heise David, Frank Ulrich Toward modeling constructs for audit risk assessment: Reflections on internal controls modeling..............................................................................................131 Schlieter Hannes, Bürger Maik, Esswein Werner Konstruktion eines adaptiven Referenzmodells für den ambulanten Sektor.....149 Deindl Matthias, Naß Eric, Beckhoff Tim Anwendung der enhanced Telecom Operations Map auf Dienstleistungsunternehmen in der Stromwirtschaft am Beispiel eines Prozesses im Bereich Messwesen.........................................................................................................171 Komponentenorientierte betriebliche Anwendungssysteme Schrödl Holger Service- und komponentenorientierte Informationssystemarchitekturen für die strategische Beschaffung von hybriden Produkten – ein Vergleichsrahmen.....................................................................................195 Houy Constantin, Reiter Markus, Fettke Peter, Loos Peter Potentiale serviceorientierter Architekturen für Software-Werkzeuge des Geschäftsprozessmanagements..........................................................................211 Sadek Tim, Meuris Daniel Datentechnische Integration und Visualisierung von Anforderungen innerhalb von CAD-Systemen...........................................................................................229
264

Feasibility of Game Theory and Mechanism Design Techniques to Understand Game Balance

Prajwal Balasubramani (9192782) 03 August 2020 (has links)
Game balance has been a challenge for game developers since the time games have become more complex. There have been a handful of proposals for game balancing processes outside the manual labor-intensive play testing methods, which most game developers often are forced to use simply due to the lack of better methods. Simple solutions, like restrictive game play, are limited because of their inability to provide insight on interdependencies among the mechanisms in the game. Complex techniques framed around the potential of AI algorithms are limited by computational budgets or cognition inability to assess human actions. In order to find a middle ground we investigate Game Theory and Mechanism Design concepts. Both have proven to be effective tools to analyse strategic situations among interacting participants, or in this case `players'. We test the feasibility of using these techniques in an Real Time Strategy (RTS) game domain to understand game balance. MicroRTS, a small and simple execution of an RTS game is employed as our model. The results provide promising insight on the effectiveness of the method in detecting imbalances and further inspection to find the cause. An additional benefit out of this technique, besides detecting for game imbalances, the approach can be leveraged to create imbalances. This is useful when the designer or player desires to do so.
265

A Combined Formal Model for Relational Context-Dependent Roles

Kühn, Thomas, Böhme, Stephan, Götz, Sebastian, Aßmann, Uwe 08 June 2021 (has links)
Role-based modeling has been investigated for over 35 years as a promising paradigm to model complex, dynamic systems. Although current software systems are characterized by increasing complexity and context-dependence, all this research had almost no influence on current software development practice, still being discussed in recent literature. One reason for this is the lack of a coherent, comprehensive, readily applicable notion of roles. Researchers focused either on relational roles or context-dependent roles rather then combining both natures. Currently, there is no role-based modeling language sufficiently incorporating both the relational and context-dependent nature of roles together with the various proposed constraints. Hence, this paper formalizes a full-fledged role-based modeling language supporting both natures. To show its sufficiency and adequacy, a real world example is employed.
266

FRaMED: Full-Fledge Role Modeling Editor (Tool Demo)

Kühn, Thomas, Bierzynski, Kay, Richly, Sebastian, Aßmann, Uwe 09 June 2021 (has links)
Since the year 1977, role modeling has been continuously investigated as promising paradigm to model complex, dynamic systems. However, this research had almost no influence on the design of todays increasingly complex and context-sensitive software systems. The reason for that is twofold. First, most modeling languages focused either on the behavioral, relational or context-dependent nature of roles rather than combining them. Second, there is a lack of tool support for the design, validation, and generation of role-based software systems. In particular, there exists no graphical role modeling editor supporting the three natures as well as the various proposed constraints. To overcome this deficiency, we introduce the Full-fledged Role Modeling Editor (FRaMED), a graphical modeling editor embracing all natures of roles and modeling constraints featuring generators for a formal representation and source code of a rolebased programming language. To show its applicability for the development of role-based software systems, an example from the banking domain is employed.
267

A Systems-Level Approach to the Design, Evaluation, and Optimization of Electrified Transportation Networks Using Agent-Based Modeling

Willey, Landon Clark 16 June 2020 (has links)
Rising concerns related to the effects of traffic congestion have led to the search for alternative transportation solutions. Advances in battery technology have resulted in an increase of electric vehicles (EVs), which serve to reduce the impact of many of the negative consequences of congestion, including pollution and the cost of wasted fuel. Furthermore, the energy-efficiency and quiet operation of electric motors have made feasible concepts such as Urban Air Mobility (UAM), in which electric aircraft transport passengers in dense urban areas prone to severe traffic slowdowns. Electrified transportation may be the solution needed to combat urban gridlock, but many logistical questions related to the design and operation of the resultant transportation networks remain to be answered. This research begins by examining the near-term effects of EV charging networks. Stationary plug-in methods have been the traditional approach to recharge electric ground vehicles; however, dynamic charging technologies that can charge vehicles while they are in motion have recently been introduced that have the potential to eliminate the inconvenience of long charging wait times and the high cost of large batteries. Using an agent-based model verified with traffic data, different network designs incorporating these dynamic chargers are evaluated based on the predicted benefit to EV drivers. A genetic optimization is designed to optimally locate the chargers. Heavily-used highways are found to be much more effective than arterial roads as locations for these chargers, even when installation cost is taken into consideration. This work also explores the potential long-term effects of electrified transportation on urban congestion by examining the implementation of a UAM system. Interdependencies between potential electric air vehicle ranges and speeds are explored in conjunction with desired network structure and size in three different regions of the United States. A method is developed to take all these considerations into account, thus allowing for the creation of a network optimized for UAM operations when vehicle or topological constraints are present. Because the optimization problem is NP-hard, five heuristic algorithms are developed to find potential solutions with acceptable computation times, and are found to be within 10% of the optimal value for the test cases explored. The results from this exploration are used in a second agent-based transportation model that analyzes operational parameters associated with UAM networks, such as service strategy and dispatch frequency, in addition to the considerations associated with network design. General trends between the effectiveness of UAM networks and the various factors explored are identified and presented.
268

Modeling economic resilience / Modéliser la résilience économique

Colon, Célian 02 December 2016 (has links)
De grandes transformations écologiques et climatiques sont aujourd'hui à l’œuvre. Elles sont sources d’instabilité environnementale, à l’image d’évènements climatiques extrêmes devenus plus fréquents, plus intenses, et touchant de nouvelles régions du globe. A défaut de pouvoir empêcher ces changements, comment les sociétés humaines pourraient-elles s'y adapter ? Pour beaucoup de chercheurs et de décideurs, c’est par la résilience qu’elles y parviendront. Ce concept semble renfermer des solutions nouvelles, adaptées à un monde turbulent et incertain. Par définition, les systèmes résilients sont capables de rebondir face à des chocs inattendus, d’apprendre rapidement et de s'adapter à des conditions inédites. Malgré l’intérêt suscité par cette notion, les processus qui permettent à une société d’être résiliente restent encore mal connus. Cette thèse développe un cadre conceptuel nouveau permettant, via la modélisation mathématique, d'explorer les liens théoriques entre mécanismes économiques et résilience. Ce cadre repose sur une analyse critique de la résilience en écologie — domaine d’origine du concept — et en économie — notre champ d’application. Nous l’appliquons aux systèmes de production économique, modélisés comme des réseaux de firmes et analysés à travers la théorie des systèmes dynamiques. Cette thèse évalue l’aptitude de tels modèles, dits multi-agents, à générer des profils de bifurcations, étape incontournable de l’analyse mathématique de la résilience. Nous étudions pour cela une dynamique proie–prédateur très générale en écologie et en économie. Ensuite, cette thèse s'attaque à un facteur majeur qui entrave la résilience : les fortes interdépendances entre activités économiques, par lesquelles les retards et interruptions de production se propagent d’une entreprise à l’autre. En utilisant des réseaux de production réalistes, nous montrons comment les délais d'approvisionnement, lorsque intégrés dans des topologies particulières, démultiplient ces phénomènes de propagation. Ensuite, grâce à un modèle évolutionnaire, nous mettons en lumière l’existence d’un risque systémique : les cascades d’incidents ont lieu alors même que tous les agents possèdent des inventaires adaptés au niveau de risque. Ce phénomène s’amplifie lorsque les chaînes d'approvisionnement se spécialisent et se fragmentent. Ces résultats théoriques ont une valeur générale, et pourront servir à orienter de futures recherches empiriques. Cette thèse fait en outre avancer les connaissances sur des méthodes et objets mathématiques très récents, comme les équations booléennes à retard formant un réseau complexe, et les dynamiques évolutionnaires sur les graphes. Les modèles et le cadre conceptuel proposés ouvrent de nouvelles perspectives de recherche sur la résilience, en particulier sur l’impact des rétroactions environnementales sur l'évolution structurelle des réseaux de production. / A wide range of climatic and ecological changes are unfolding around us. These changes notably manifest themselves through an increased environmental variability, such as shifts in the frequency, intensity, and spatial distribution of weather-related extreme events. If human societies cannot mitigate these transformations, to which conditions should they adapt? To many researchers and stakeholders, the answer is resilience. This concept seems to subsume a variety of solutions for dealing with a turbulent and uncertain world. Resilient systems bounce back after unexpected events, learn novel conditions and adapt to them. Theoretical models, however, to explore the links between socioeconomic mechanisms and resilience are still in their infancy. To advance such models, the present dissertation proposes a novel conceptual framework. This framework relies on an interdisciplinary and critical review of ecological and economic studies, and it is based on the theory of dynamical systems and on the paradigm of complex adaptive systems. We identify agent-based models as crucial for socioeconomic modeling. To assess their applicability to the study of resilience, we test at first whether such models can reproduce the bifurcation patterns of predator–prey interactions, which are a very important factor in both ecological and economic systems. The dissertation then tackles one of the main challenges for the design of resilient economic system: the large interconnectedness of production processes, whereby disruption may propagate and amplify. We next investigate the role of delays in production and supply on realistic economic networks, and show that the interplay between time delays and topology may greatly affect a network’s resilience. Finally, we investigate a model that encompasses adaptive responses of agents to shocks, and describes how disruptions propagate even though all firms do their best to mitigate risks. In particular, systemic amplification gets more pronounced when supply chains are fragmented. These theoretical findings are fairly general in character and may thus help the design of novel empirical studies. Through the application of several recent ideas and methods, this dissertation advances knowledge on innovative mathematical objects, such as Boolean delay equations on complex networks and evolutionary dynamics on graphs. Finally, the conceptual models herein open wide perspectives for further theoretical research on economic resilience, especially the study of environmental feedbacks and their impacts on the structural evolution of production networks.
269

Agent-Based Overlapping Generations Modeling for Educational Policy Analysis

Wang, Connie Hou-Ning 01 January 2017 (has links)
Educational systems are complex adaptive systems (CAS). The macroeffects of an educational policy emerge from and depend on individual students' reactions to the policy. However, educational policymakers traditionally rely on equation-based models, which are deficient in reflecting the work of microbehaviors. Using inappropriate tools to make policies may be a reason why there were many unintended educational consequences in history. A proper methodology to design and analyze policies for complex educational systems is agent-based modeling (ABM). Grounded in the theories of CAS and computational irreducibility, ABM is capable of connecting microbehaviors with macropatterns. The purpose of this study was to contribute to the application of ABM in educational policy analysis by constructing an agent-based overlapping generations model with hypothesized inputs to qualitatively represent the environment of the Taipei School District. Four research questions explored the effects of Taipei's 2016 student-assignment mechanism and its free tuition policy on educational opportunity and school quality under different assumptions of students' school-choice strategies. The simulated outputs were analyzed using descriptive statistics and paired samples t tests. The findings, which could hardly be revealed by traditional models, showed that the effects were complex and depended on students' strategies along with the number of choices students were allowed to make; the assignment outcomes for elite students were robust to the mechanism, and the free tuition policy worsened school quality. Although exploratory, these findings can serve as hypotheses and a guide for Taipei's policymakers to collect empirical data in evaluating their 2016 mechanism and tuition policy.
270

ADAPTIVE DECISION SUPPORT SYSTEM TO NAVIGATE THE COMPLEXITY OF POST-DISASTER DEBRIS MANAGEMENT

Jooho Kim (7818005) 05 November 2019 (has links)
<div>Disaster debris management is critical to the success of disaster recovery systems. While there are multiple disaster mitigation strategies and post-disaster debris management plans, it is hard to implement because of: (i) the uniqueness of disaster incidents and randomness of its impacts; (ii) complexity of disaster debris removal operations, policy and regulations and (iii) interdependency of multiple infrastructure networks. Also, delayed debris removal operation affects following emergency response activities. Furthermore, uncontrolled debris removal activities can result in significant environmental and public health consequences. Therefore, there is a need for a systematic approach to optimizing post-disaster debris management systems. </div><div><br></div><div>This research is aimed to understand the complexity of debris management and associated emergent dynamics through the lens of an adaptive system-of-systems (SoS). To develop the adaptive decision support system, this research (a) identifies the interdependent infrastructure network within a community and its relative importance; (b) develops real-time GIS database to integrate the data associated with critical infrastructure and geographical characteristics in the community map; (c) designs and selects a TDMS network to analyze the required number, capacity and resources, based on engineering-technical, managerial, and social-political dynamics; (d) simulate the productivity of debris-management SoS based on the real-time GIS database to gain insight into the impact of the dynamical nature of a disaster-affected area; and (e) develop a visualized interactive GIS-based platform for debris management to communicate real-time debris clearance strategies and operations among different agencies and organizations.</div><div><br></div><div>To evaluate the proposed framework and decision support system, this research conducted a case study, debris removal operation in the city of Baton Rouge, after the 2016 Louisiana flood. The results demonstrated the influence of sub-systems such as TDMS locations and capacity, road network condition, available resources, existing regulations and policies, characteristics of community on the behavior of the entire disaster debris removal management as a whole. </div><div><br></div><div>The proposed decision support system for effective disaster debris management will be beneficial for emergency agencies and disaster-prone communities to evaluate and optimize their disaster debris management system. Also, the system can be systematically integrated with other emergency response systems to maximize the efficiency of the entire disaster responses during post-disaster situations. </div><div><br></div>

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