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Today, it is well known that galaxies like the Milky Way consist not only of stars but also of gas and dust. The galactic halo, a sphere of gas that surrounds the stellar disk of a galaxy, is especially interesting. It provides a wealth of information about in and outflowing gaseous material towards and away from galaxies and their hierarchical evolution. For the Milky Way, the so-called high-velocity clouds (HVCs), fast moving neutral gas complexes in the halo that can be traced by absorption-line measurements, are believed to play a crucial role in the overall matter cycle in our Galaxy. Over the last decades, the properties of these halo structures and their connection to the local circumgalactic and intergalactic medium (CGM and IGM, respectively) have been investigated in great detail by many different groups. So far it remains unclear, however, to what extent the results of these studies can be transferred to other galaxies in the local Universe. In this thesis, we study the absorption properties of Galactic HVCs and compare the HVC absorption characteristics with those of intervening QSO absorption-line systems at low redshift. The goal of this project is to improve our understanding of the spatial extent and physical conditions of gaseous galaxy halos in the local Universe. In the first part of the thesis we use HST /STIS ultraviolet spectra of more than 40 extragalactic background sources to statistically analyze the absorption properties of the HVCs in the Galactic halo. We determine fundamental absorption line parameters including covering fractions of different weakly/intermediately/highly ionized metals with a particular focus on SiII and MgII. Due to the similarity in the ionization properties of SiII and MgII, we are able to estimate the contribution of HVC-like halo structures to the cross section of intervening strong MgII absorbers at z = 0. Our study implies that only the most massive HVCs would be regarded as strong MgII absorbers, if the Milky Way halo would be seen as a QSO absorption line system from an exterior vantage point. Combining the observed absorption-cross section of Galactic HVCs with the well-known number density of intervening strong MgII absorbers at z = 0, we conclude that the contribution of infalling gas clouds (i.e., HVC analogs) in the halos of Milky Way-type galaxies to the cross section of strong MgII absorbers is 34%. This result indicates that only about one third of the strong MgII absorption can be associated with HVC analogs around other galaxies, while the majority of the strong MgII systems possibly is related to galaxy outflows and winds. The second part of this thesis focuses on the properties of intervening metal absorbers at low redshift. The analysis of the frequency and physical conditions of intervening metal systems in QSO spectra and their relation to nearby galaxies offers new insights into the typical conditions of gaseous galaxy halos. One major aspect in our study was to regard intervening metal systems as possible HVC analogs. We perform a detailed analysis of absorption line properties and line statistics for 57 metal absorbers along 78 QSO sightlines using newly-obtained ultraviolet spectra obtained with HST /COS. We find clear evidence for bimodal distribution in the HI column density in the absorbers, a trend that we interpret as sign for two different classes of absorption systems (with HVC analogs at the high-column density end). With the help of the strong transitions of SiII λ1260, SiIII λ1206, and CIII λ977 we have set up Cloudy photoionization models to estimate the local ionization conditions, gas densities, and metallicities. We find that the intervening absorption systems studied by us have, on average, similar physical conditions as Galactic HVC absorbers, providing evidence that many of them represent HVC analogs in the vicinity of other galaxies. We therefore determine typical halo sizes for SiII, SiIII, and CIII for L = 0.01L∗ and L = 0.05L∗ galaxies. Based on the covering fractions of the different ions in the Galactic halo, we find that, for example, the typical halo size for SiIII is ∼ 160 kpc for L = 0.05L∗ galaxies. We test the plausibility of this result by searching for known galaxies close to the QSO sightlines and at similar redshifts as the absorbers. We find that more than 34% of the measured SiIII absorbers have galaxies associated with them, with the majority of the absorbers indeed being at impact parameters ρ ≤160 kpc.
Organizations try to gain competitive advantages, and to increase customer satisfaction. To ensure the quality and efficiency of their business processes, they perform business process management. An important part of process management that happens on the daily operational level is process controlling. A prerequisite of controlling is process monitoring, i.e., keeping track of the performed activities in running process instances. Only by process monitoring can business analysts detect delays and react to deviations from the expected or guaranteed performance of a process instance. To enable monitoring, process events need to be collected from the process environment. When a business process is orchestrated by a process execution engine, monitoring is available for all orchestrated process activities. Many business processes, however, do not lend themselves to automatic orchestration, e.g., because of required freedom of action. This situation is often encountered in hospitals, where most business processes are manually enacted. Hence, in practice it is often inefficient or infeasible to document and monitor every process activity. Additionally, manual process execution and documentation is prone to errors, e.g., documentation of activities can be forgotten. Thus, organizations face the challenge of process events that occur, but are not observed by the monitoring environment. These unobserved process events can serve as basis for operational process decisions, even without exact knowledge of when they happened or when they will happen. An exemplary decision is whether to invest more resources to manage timely completion of a case, anticipating that the process end event will occur too late. This thesis offers means to reason about unobserved process events in a probabilistic way. We address decisive questions of process managers (e.g., "when will the case be finished?", or "when did we perform the activity that we forgot to document?") in this thesis. As main contribution, we introduce an advanced probabilistic model to business process management that is based on a stochastic variant of Petri nets. We present a holistic approach to use the model effectively along the business process lifecycle. Therefore, we provide techniques to discover such models from historical observations, to predict the termination time of processes, and to ensure quality by missing data management. We propose mechanisms to optimize configuration for monitoring and prediction, i.e., to offer guidance in selecting important activities to monitor. An implementation is provided as a proof of concept. For evaluation, we compare the accuracy of the approach with that of state-of-the-art approaches using real process data of a hospital. Additionally, we show its more general applicability in other domains by applying the approach on process data from logistics and finance.
The objective and motivation behind this research is to provide applications with easy-to-use interfaces to communities of deaf and functionally illiterate users, which enables them to work without any human assistance. Although recent years have witnessed technological advancements, the availability of technology does not ensure accessibility to information and communication technologies (ICT). Extensive use of text from menus to document contents means that deaf or functionally illiterate can not access services implemented on most computer software. Consequently, most existing computer applications pose an accessibility barrier to those who are unable to read fluently. Online technologies intended for such groups should be developed in continuous partnership with primary users and include a thorough investigation into their limitations, requirements and usability barriers. In this research, I investigated existing tools in voice, web and other multimedia technologies to identify learning gaps and explored ways to enhance the information literacy for deaf and functionally illiterate users. I worked on the development of user-centered interfaces to increase the capabilities of deaf and low literacy users by enhancing lexical resources and by evaluating several multimedia interfaces for them. The interface of the platform-independent Italian Sign Language (LIS) Dictionary has been developed to enhance the lexical resources for deaf users. The Sign Language Dictionary accepts Italian lemmas as input and provides their representation in the Italian Sign Language as output. The Sign Language dictionary has 3082 signs as set of Avatar animations in which each sign is linked to a corresponding Italian lemma. I integrated the LIS lexical resources with MultiWordNet (MWN) database to form the first LIS MultiWordNet(LMWN). LMWN contains information about lexical relations between words, semantic relations between lexical concepts (synsets), correspondences between Italian and sign language lexical concepts and semantic fields (domains). The approach enhances the deaf users’ understanding of written Italian language and shows that a relatively small set of lexicon can cover a significant portion of MWN. Integration of LIS signs with MWN made it useful tool for computational linguistics and natural language processing. The rule-based translation process from written Italian text to LIS has been transformed into service-oriented system. The translation process is composed of various modules including parser, semantic interpreter, generator, and spatial allocation planner. This translation procedure has been implemented in the Java Application Building Center (jABC), which is a framework for extreme model driven design (XMDD). The XMDD approach focuses on bringing software development closer to conceptual design, so that the functionality of a software solution could be understood by someone who is unfamiliar with programming concepts. The transformation addresses the heterogeneity challenge and enhances the re-usability of the system. For enhancing the e-participation of functionally illiterate users, two detailed studies were conducted in the Republic of Rwanda. In the first study, the traditional (textual) interface was compared with the virtual character-based interactive interface. The study helped to identify usability barriers and users evaluated these interfaces according to three fundamental areas of usability, i.e. effectiveness, efficiency and satisfaction. In another study, we developed four different interfaces to analyze the usability and effects of online assistance (consistent help) for functionally illiterate users and compared different help modes including textual, vocal and virtual character on the performance of semi-literate users. In our newly designed interfaces the instructions were automatically translated in Swahili language. All the interfaces were evaluated on the basis of task accomplishment, time consumption, System Usability Scale (SUS) rating and number of times the help was acquired. The results show that the performance of semi-literate users improved significantly when using the online assistance. The dissertation thus introduces a new development approach in which virtual characters are used as additional support for barely literate or naturally challenged users. Such components enhanced the application utility by offering a variety of services like translating contents in local language, providing additional vocal information, and performing automatic translation from text to sign language. Obviously, there is no such thing as one design solution that fits for all in the underlying domain. Context sensitivity, literacy and mental abilities are key factors on which I concentrated and the results emphasize that computer interfaces must be based on a thoughtful definition of target groups, purposes and objectives.
The contractile vacuole (CV) is an osmoregulatory organelle found exclusively in algae and protists. In addition to expelling excessive water out of the cell, it also expels ions and other metabolites and thereby contributes to the cell's metabolic homeostasis. The interest in the CV reaches beyond its immediate cellular roles. The CV's function is tightly related to basic cellular processes such as membrane dynamics and vesicle budding and fusion; several physiological processes in animals, such as synaptic neurotransmission and blood filtration in the kidney, are related to the CV's function; and several pathogens, such as the causative agents of sleeping sickness, possess CVs, which may serve as pharmacological targets. The green alga Chlamydomonas reinhardtii has two CVs. They are the smallest known CVs in nature, and they remain relatively untouched in the CV-related literature. Many genes that have been shown to be related to the CV in other organisms have close homologues in C. reinhardtii. We attempted to silence some of these genes and observe the effect on the CV. One of our genes, VMP1, caused striking, severe phenotypes when silenced. Cells exhibited defective cytokinesis and aberrant morphologies. The CV, incidentally, remained unscathed. In addition, mutant cells showed some evidence of disrupted autophagy. Several important regulators of the cell cycle as well as autophagy were found to be underexpressed in the mutant. Lipidomic analysis revealed many meaningful changes between wild-type and mutant cells, reinforcing the compromised-autophagy observation. VMP1 is a singular protein, with homologues in numerous eukaryotic organisms (aside from fungi), but usually with no relatives in each particular genome. Since its first characterization in 2002 it has been associated with several cellular processes and functions, namely autophagy, programmed cell-death, secretion, cell adhesion, and organelle biogenesis. It has been implicated in several human diseases: pancreatitis, diabetes, and several types of cancer. Our results reiterate some of the observations in VMP1's six reported homologues, but, importantly, show for the first time an involvement of this protein in cell division. The mechanisms underlying this involvement in Chlamydomonas, as well as other key aspects, such as VMP1's subcellular localization and interaction partners, still await elucidation.
In Chapter 1 of the dissertation, the role of social networks is analyzed as an important determinant in the search behavior of the unemployed. Based on the hypothesis that the unemployed generate information on vacancies through their social network, search theory predicts that individuals with large social networks should experience an increased productivity of informal search, and reduce their search in formal channels. Due to the higher productivity of search, unemployed with a larger network are also expected to have a higher reservation wage than unemployed with a small network. The model-theoretic predictions are tested and confirmed empirically. It is found that the search behavior of unemployed is significantly affected by the presence of social contacts, with larger networks implying a stronger substitution away from formal search channels towards informal channels. The substitution is particularly pronounced for passive formal search methods, i.e., search methods that generate rather non-specific types of job offer information at low relative cost. We also find small but significant positive effects of an increase of the network size on the reservation wage. These results have important implications on the analysis of the job search monitoring or counseling measures that are usually targeted at formal search only. Chapter 2 of the dissertation addresses the labor market effects of vacancy information during the early stages of unemployment. The outcomes considered are the speed of exit from unemployment, the effects on the quality of employment and the short-and medium-term effects on active labor market program (ALMP) participation. It is found that vacancy information significantly increases the speed of entry into employment; at the same time the probability to participate in ALMP is significantly reduced. Whereas the long-term reduction in the ALMP arises in consequence of the earlier exit from unemployment, we also observe a short-run decrease for some labor market groups which suggest that caseworker use high and low intensity activation measures interchangeably which is clearly questionable from an efficiency point of view. For unemployed who find a job through vacancy information we observe a small negative effect on the weekly number of hours worked. In Chapter 3, the long-term effects of participation in ALMP are assessed for unemployed youth under 25 years of age. Complementary to the analysis in Chapter 2, the effects of participation in time- and cost-intensive measures of active labor market policies are examined. In particular we study the effects of job creation schemes, wage subsidies, short-and long-term training measures and measures to promote the participation in vocational training. The outcome variables of interest are the probability to be in regular employment, and participation in further education during the 60 months following program entry. The analysis shows that all programs, except job creation schemes have positive and long-term effects on the employment probability of youth. In the short-run only short-term training measures generate positive effects, as long-term training programs and wage subsidies exhibit significant locking-in'' effects. Measures to promote vocational training are found to increase the probability of attending education and training significantly, whereas all other programs have either no or a negative effect on training participation. Effect heterogeneity with respect to the pre-treatment level education shows that young people with higher pre-treatment educational levels benefit more from participation most programs. However, for longer-term wage subsidies we also find strong positive effects for young people with low initial education levels. The relative benefit of training measures is higher in West than in East Germany. In the evaluation studies of Chapters 2 and 3 semi-parametric balancing methods of Propensity Score Matching (PSM) and Inverse Probability Weighting (IPW) are used to eliminate the effects of counfounding factors that influence both the treatment participation as well as the outcome variable of interest, and to establish a causal relation between program participation and outcome differences. While PSM and IPW are intuitive and methodologically attractive as they do not require parametric assumptions, the practical implementation may become quite challenging due to their sensitivity to various data features. Given the importance of these methods in the evaluation literature, and the vast number of recent methodological contributions in this field, Chapter 4 aims to reduce the knowledge gap between the methodological and applied literature by summarizing new findings of the empirical and statistical literature and practical guidelines for future applied research. In contrast to previous publications this study does not only focus on the estimation of causal effects, but stresses that the balancing challenge can and should be discussed independent of question of causal identification of treatment effects on most empirical applications. Following a brief outline of the practical implementation steps required for PSM and IPW, these steps are presented in detail chronologically, outlining practical advice for each step. Subsequently, the topics of effect estimation, inference, sensitivity analysis and the combination with parametric estimation methods are discussed. Finally, new extensions of the methodology and avenues for future research are presented.
Im Rahmen der Dissertation wird die Anwendung und Wirkung von Kernelementen des New Public Management (NPM) am Beispiel der Bürgerdienste der sechs europäischen Hauptstädte Berlin, Brüssel, Kopenhagen, Madrid, Prag und Warschau analysiert. Hierbei steht der Vergleich von Hauptstädten der MOE-Staaten mit Hauptstädten alter EU-Mitgliedsstaaten im Vordergrund. Es wird die folgende Forschungshypothese untersucht: Die Verwaltungen in den Hauptstädten der östlichen Mitgliedsstaaten der EU haben in Folge der grundsätzlichen gesellschaftlichen und politischen Umbrüche in den 1990er Jahren bedeutend mehr Kernelemente des NPM beim Neuaufbau ihrer öffentlichen Verwaltungen eingeführt. Durch den folgerichtigen Aufbau kundenorientierter und moderner Verwaltungen sowie der strikten Anwendung der Kernelemente des New Public Management arbeiten die Bürgerdienste in den Hauptstädten östlicher EU-Mitgliedsstaaten effizienter und wirkungsvoller als vergleichbare Bürgerdienste in den Hauptstädten westlicher EU-Mitgliedsstaaten. Zur Überprüfung der Forschungshypothese werden die Vergleichsstädte zunächst den entsprechenden Rechts- und Verwaltungstraditionen (kontinentaleuropäisch deutsch, napoleonisch und skandinavisch) zugeordnet und bezüglich ihrer Ausgangslage zum Aufbau einer modernen Verwaltung (Westeuropäische Verwaltung, Wiedervereinigungsverwaltung und Transformations-verwaltung) kategorisiert. Im Anschluss werden die institutionellen Voraussetzungen hinterfragt, was die deskriptive Darstellung der Stadt- und Verwaltungsgeschichte sowie die Untersuchung von organisatorischen Strukturen der Bürgerdienste, die Anwendung der NPM-Instrumente als auch die Innen- und Außenperspektive des NPM umfasst. Es wird festgestellt, ob und in welcher Form die Bürgerdienste der Vergleichsstädte die Kernelemente des NPM anwenden. Im Anschluss werden die Vergleichsstädte bezüglich der Anwendung der Kernelemente miteinander verglichen, wobei der Fokus auf dem persönlichen Vertriebsweg und der Kundenorientierung liegt. Der folgende Teil der Dissertation befasst sich mit dem Output der Bürgerdienste, der auf operative Resultate untersucht und verglichen wird. Hierbei stellt sich insbesondere die Frage nach den Leistungsmengen und der Produktivität des Outputs. Es werden aber auch die Ergebnisse von Verwaltungsprozessen untersucht, insbesondere in Bezug auf die Kundenorientierung. Hierfür wird ein Effizienzvergleich der Bürgerdienste in den Vergleichsstädten anhand einer relativen Effizienzmessung und der Free Disposal Hull (FDH)-Methode nach Bouckaert durchgeführt. Es ist eine Konzentration auf populäre Dienstleistungen aus dem Portfolio der Bürgerdienste notwendig. Daher werden die vergleichbaren Dienstleistungen Melde-, Personalausweis-, Führerschein- und Reisepass-angelegenheiten unter Einbeziehung des Vollzeitäquivalents zur Berechnung der Effizienz der Bürgerdienste herangezogen. Hierfür werden Daten aus den Jahren 2009 bis 2011 genutzt, die teilweise aus verwaltungsinternen Datenbanken stammen. Anschließend wird der Versuch unternommen, den Outcome in die Effizienzanalyse der Bürgerdienste einfließen zu lassen. In diesem Zusammenhang wird die Anwendbarkeit von verschiedenen erweiterten Best-Practice-Verfahren und auch eine Erweiterung der relativen Effizienzmessung und der FDH-Methode geprüft. Als Gesamtfazit der Dissertation kann festgehalten werden, dass die Bürgerdienste in den untersuchten Hauptstädten der MOE-Staaten nicht mehr Kernelemente des NPM anwenden, als die Hauptstädte der westlichen Mitgliedsstaaten der EU. Im Gegenteil wendet Prag deutlich weniger NPM-Instrumente als andere Vergleichsstädte an, wohingegen Warschau zwar viele NPM-Instrumente anwendet, jedoch immer von einer westeuropäischen Vergleichsstadt übertroffen wird. Auch die Hypothese, dass die Bürgerdienste in den Hauptstädten der MOE-Staaten effizienter arbeiten als vergleichbare Bürgerdienste in den Hauptstädten westlicher EU-Mitgliedsstaaten wurde durch die Dissertation entkräftet. Das Gegenteil ist der Fall, da Prag und Warschau im Rahmen des Effizienzvergleichs lediglich durchschnittliche oder schlechte Performances aufweisen. Die aufgestellte Hypothese ist durch die Forschungsergebnisse widerlegt, lediglich das gute Abschneiden der Vergleichsstadt Warschau bei der Anwendungsanalyse kann einen Teil der These im gewissen Umfang bestätigen.
The term Linked Data refers to connected information sources comprising structured data about a wide range of topics and for a multitude of applications. In recent years, the conceptional and technical foundations of Linked Data have been formalized and refined. To this end, well-known technologies have been established, such as the Resource Description Framework (RDF) as a Linked Data model or the SPARQL Protocol and RDF Query Language (SPARQL) for retrieving this information. Whereas most research has been conducted in the area of generating and publishing Linked Data, this thesis presents novel approaches for improved management. In particular, we illustrate new methods for analyzing and processing SPARQL queries. Here, we present two algorithms suitable for identifying structural relationships between these queries. Both algorithms are applied to a large number of real-world requests to evaluate the performance of the approaches and the quality of their results. Based on this, we introduce different strategies enabling optimized access of Linked Data sources. We demonstrate how the presented approach facilitates effective utilization of SPARQL endpoints by prefetching results relevant for multiple subsequent requests. Furthermore, we contribute a set of metrics for determining technical characteristics of such knowledge bases. To this end, we devise practical heuristics and validate them through thorough analysis of real-world data sources. We discuss the findings and evaluate their impact on utilizing the endpoints. Moreover, we detail the adoption of a scalable infrastructure for improving Linked Data discovery and consumption. As we outline in an exemplary use case, this platform is eligible both for processing and provisioning the corresponding information.
Anorexia nervosa und unipolare Affektive Störungen stellen häufige und schwerwiegende kinder- und jugendpsychiatrische Störungsbilder dar, deren Pathogenese bislang nicht vollständig entschlüsselt ist. Verschiedene Studien zeigen bei erwachsenen Patienten gravierende Auffälligkeiten in den kognitiven Funktionen. Dahingegen scheinen bei adoleszenten Patienten lediglich leichtere Einschränkungen in den kognitiven Funktionen vorzuliegen. Die Prävalenz der Anorexia nervosa und unipolaren Affektiven Störung ist mit Beginn der Adoleszenz deutlich erhöht. Es ist anzunehmen, dass kognitive Dysfunktionen, die sich bereits in diesem Alter abzeichnen, den weiteren Krankheitsverlauf bis in das Erwachsenenalter, die Behandlungsergebnisse und die Prognose maßgeblich beeinträchtigen könnten. Zudem ist von einem höheren Chronifizierungsrisiko auszugehen. In der vorliegenden Arbeit wurden daher kognitive Funktionen bei adoleszenten Patientinnen mit Anorexia nervosa sowie Patienten mit unipolaren Affektiven Störungen untersucht. Die Überprüfung der kognitiven Funktionen bei Patientinnen mit Anorexia nervosa erfolgte vor und nach Gewichtszunahme. Weiterhin wurden zugrundeliegende biologische Mechanismen überprüft. Zudem wurde die Spezifität kognitiver Dysfunktionen für beide Störungsbilder untersucht und bei Patienten mit unipolaren Affektiven Störungen geschlechtsbezogene Unterschiede exploriert. Insgesamt gingen 47 Patientinnen mit Anorexia nervosa (mittleres Alter 16,3 + 1,6 Jahre), 39 Patienten mit unipolaren Affektiven Störungen (mittleres Alter 15,5 + 1,3 Jahre) sowie 78 Kontrollprobanden (mittleres Alter 16,5 + 1,3 Jahre) in die Untersuchung ein. Sämtliche Studienteilnehmer durchliefen eine neuropsychologische Testbatterie, bestehend aus Verfahren zur Überprüfung der kognitiven Flexibilität sowie visuellen und psychomotorischen Verarbeitungsgeschwindigkeit. Neben einem Intelligenzscreening wurden zudem das Ausmaß der depressiven Symptomatik sowie die allgemeine psychische Belastung erfasst. Die Ergebnisse legen nahe, dass bei adoleszenten Patientinnen mit Anorexia nervosa, sowohl im akut untergewichtigen Zustand als auch nach Gewichtszunahme, lediglich milde Beeinträchtigungen in den kognitiven Funktionen vorliegen. Im akut untergewichtigen Zustand offenbarten sich deutliche Zusammenhänge zwischen dem appetitregulierenden Peptid Agouti-related Protein und kognitiver Flexibilität, nicht jedoch zwischen Agouti-related Protein und visueller oder psychomotorischer Verarbeitungsgeschwindigkeit. Bei dem Vergleich von Anorexia nervosa und unipolaren Affektiven Störungen prädizierte die Zugehörigkeit zu der Patientengruppe Anorexia nervosa ein Risiko für das Vorliegen kognitiver Dysfunktionen. Es zeigte sich zudem, dass adoleszente Patienten mit unipolaren Affektiven Störungen lediglich in der psychomotorischen Verarbeitungsgeschwindigkeit tendenziell schwächere Leistungen offenbarten als gesunde Kontrollprobanden. Es ergab sich jedoch ein genereller geschlechtsbezogener Vorteil für weibliche Probanden in der visuellen und psychomotorischen Verarbeitungsgeschwindigkeit. Die vorliegenden Befunde unterstreichen die Notwendigkeit der Überprüfung kognitiver Funktionen bei adoleszenten Patienten mit Anorexia nervosa sowie unipolaren Affektiven Störungen in der klinischen Routinediagnostik. Die Patienten könnten von spezifischen Therapieprogrammen profitieren, die Beeinträchtigungen in den kognitiven Funktionen mildern bzw. präventiv behandeln.
Planetary research is often user-based and requires considerable skill, time, and effort. Unfortunately, self-defined boundary conditions, definitions, and rules are often not documented or not easy to comprehend due to the complexity of research. This makes a comparison to other studies, or an extension of the already existing research, complicated. Comparisons are often distorted, because results rely on different, not well defined, or even unknown boundary conditions. The purpose of this research is to develop a standardized analysis method for planetary surfaces, which is adaptable to several research topics. The method provides a consistent quality of results. This also includes achieving reliable and comparable results and reducing the time and effort of conducting such studies. A standardized analysis method is provided by automated analysis tools that focus on statistical parameters. Specific key parameters and boundary conditions are defined for the tool application. The analysis relies on a database in which all key parameters are stored. These databases can be easily updated and adapted to various research questions. This increases the flexibility, reproducibility, and comparability of the research. However, the quality of the database and reliability of definitions directly influence the results. To ensure a high quality of results, the rules and definitions need to be well defined and based on previously conducted case studies. The tools then produce parameters, which are obtained by defined geostatistical techniques (measurements, calculations, classifications). The idea of an automated statistical analysis is tested to proof benefits but also potential problems of this method. In this study, I adapt automated tools for floor-fractured craters (FFCs) on Mars. These impact craters show a variety of surface features, occurring in different Martian environments, and having different fracturing origins. They provide a complex morphological and geological field of application. 433 FFCs are classified by the analysis tools due to their fracturing process. Spatial data, environmental context, and crater interior data are analyzed to distinguish between the processes involved in floor fracturing. Related geologic processes, such as glacial and fluvial activity, are too similar to be separately classified by the automated tools. Glacial and fluvial fracturing processes are merged together for the classification. The automated tools provide probability values for each origin model. To guarantee the quality and reliability of the results, classification tools need to achieve an origin probability above 50 %. This analysis method shows that 15 % of the FFCs are fractured by intrusive volcanism, 20 % by tectonic activity, and 43 % by water & ice related processes. In total, 75 % of the FFCs are classified to an origin type. This can be explained by a combination of origin models, superposition or erosion of key parameters, or an unknown fracturing model. Those features have to be manually analyzed in detail. Another possibility would be the improvement of key parameters and rules for the classification. This research shows that it is possible to conduct an automated statistical analysis of morphologic and geologic features based on analysis tools. Analysis tools provide additional information to the user and are therefore considered assistance systems.
Indonesien zählt zu den weltweit führenden Ländern bei der Nutzung von geothermischer Energie. Die geothermischen Energiequellen sind im Wesentlichen an den aktiven Vulkanismus gebunden, der durch die Prozesse an der indonesischen Subduktionszone verursacht wird. Darüber hinaus sind geotektonische Strukturen wie beispielsweise die Sumatra-Störung als verstärkende Faktoren für das geothermische Potenzial von Bedeutung. Bei der geophysikalischen Erkundung der indonesischen Geothermie-Ressourcen konzentrierte man sich bisher vor allem auf die Magnetotellurik. Passive Seismologie wurde dahingegen ausschließlich für die Überwachung von im Betrieb befindlichen Geothermie-Anlagen verwendet. Jüngste Untersuchungungen z.B. in Island und in den USA haben jedoch gezeigt, dass seismologische Verfahren bereits in der Erkundungsphase wichtige Informationen zu den physikalischen Eigenschaften, zum Spannungsfeld und zu möglichen Fluid- und Wärmetransportwegen liefern können. In der vorgelegten Doktorarbeit werden verschiedene moderne Methoden der passiven Seismologie verwendet, um beispielhaft ein neues, von der indonesischen Regierung für zukünftige geothermische Energiegewinnung ausgewiesenes Gebiet im nördlichen Teil Sumatras (Indonesien) zu erkunden. Die konkreten Ziele der Untersuchungen umfassten (1) die Ableitung von 3D Strukturmodellen der P- und S-Wellen Geschwindigkeiten (Parameter Vp und Vs), (2) die Bestimmung der Absorptionseigenschaften (Parameter Qp), und (3) die Kartierung und Charakterisierung von Störungssystemen auf der Grundlage der Seismizitätsverteilung und der Herdflächenlösungen. Für diese Zwecke habe ich zusammen mit Kollegen ein seismologisches Netzwerk in Tarutung (Sumatra) aufgebaut und über einen Zeitraum von 10 Monaten (Mai 2011 – Februar 2012) betrieben. Insgesamt wurden hierbei 42 Stationen (jeweils ausgestattet mit EDL-Datenlogger, 3-Komponenten, 1 Hz Seismometer) über eine Fläche von etwa 35 x 35 km verteilt. Mit dem Netzwerk wurden im gesamten Zeitraum 2568 lokale Erdbeben registriert. Die integrierte Betrachtung der Ergebnisse aus den verschiedenen Teilstudien (Tomographie, Erdbebenverteilung) erlaubt neue Einblicke in die generelle geologische Stukturierung sowie eine Eingrenzung von Bereichen mit einem erhöhten geothermischen Potenzial. Das tomographische Vp-Modell ermöglicht eine Bestimmung der Geometrie von Sedimentbecken entlang der Sumatra-Störung. Für die Geothermie besonders interessant ist der Bereich nordwestlich des Tarutung-Beckens. Die dort abgebildeten Anomalien (erhöhtes Vp/Vs, geringes Qp) habe ich als mögliche Aufstiegswege von warmen Fluiden interpretiert. Die scheinbar asymetrische Verteilung der Anomalien wird hierbei im Zusammenhang mit der Seismizitätsverteilung, der Geometrie der Beben-Bruchflächen, sowie struktur-geologischen Modellvorstellungen diskutiert. Damit werden wesentliche Informationen für die Planung einer zukünftigen geothermischen Anlage bereitgestellt.