Dubbed the "most murderous" and "deadliest" city in the United States during 2006, 2007 and 2008, New Orleans has wrestled with crime and murder since its founding in 1718. Following Hurricane Katrina the city saw an increase in the murder rate despite a sharp decrease in population. The focus of this project was to map homicide data trends in the city of New Orleans over a period of seven years, 2002 to 2008, and compare spatial and temporal patterns via GIS. NOPD homicide location data were geocoded and analyzed in ESRI's ArcGIS geospatial software. Methodologies of hotspot detection included point maps, choropleth graduated color maps, and quartic kernel density maps. The project's goal was to not only detect hotspots, but to create a synoptic view of shifting homicide trends throughout the city of New Orleans, highlighting the impact of Hurricane Katrina.

Cougars (Puma concolor) are a growing concern for managers of Pacific Rim National Park Reserve and Clayoquot Sound UNESCO Biosphere Reserve on the west coast of Vancouver Island, British Columbia. Since the mid-1990s, the frequency and intensity of human-cougar interactions have dramatically increased. Concurrently, these areas have become increasingly popular for human activities. The primary goal of my study was to recommend ways to reduce the potential risk of human-cougar interactions to ensure long-term conservation of cougars while minimizing risks to visitor safety. To achieve this goal, I examined the use of two noninvasive approaches. First, during 2005-2006, I compared the rate of detection, cost and time required for a detector dog, sign surveys, scented rub pads and remotely triggered cameras to detect cougars in coastal temperate rainforests. Sign surveys were the most effective method due to the availability of good tracking substrate throughout the study areas. Cameras were also practical because they could be used by less skilled personnel and had the capacity to detect several species of wildlife. Second, I demonstrated the utility of pre-existing data by analysing the spatiotemporal trends of human-cougar interactions on the West Coast Trail from 1993-2006. My results showed a moderate increase of reported human-cougar interactions (n = 157) despite a steady decline in hiker numbers across these years. I identified four areas where activities of people and cougars repeatedly overlapped (hotspots). In general, interaction locations were primarily associated with high human activity: near campsites and landscape characteristics that were associated with campsites (i.e., beaches and freshwater drainages >20 m wide). However, the distribution of hotspots suggests that the co-occurrence of human-use areas (e.g., campsites) and important travel routes (e.g., freshwater drainages and logging roads) used by cougars may increase the likelihood of interactions. These findings will allow protected area managers to proactively mitigate human-cougar conflict through visitor education and protocols that reduce people and cougars from intersecting in space and time.

Indiana University-Purdue University Indianapolis (IUPUI) / Law enforcement agencies across the U.S. use maps of crime to inform their practice and make efforts to reduce crime. Hotspot maps using historic crime data can show practitioners concentrated areas of criminal offenses and the types of offenses that have occurred; however, not all of these hotspot crime mapping techniques produce the same results. This study compares three hotspot crime mapping techniques and four crime types using the Predictive Accuracy Index (PAI) to measure the predictive accuracy of these mapping techniques in Marion County, Indiana. Results show that the grid hotspot mapping technique and crimes of robbery are most predictive. Understanding the most effective crime mapping technique will allow law enforcement to better predict and therefore prevent crimes.

Undichte Abwassersysteme sind in unserer urbanisierten Welt allgegenwärtig, und aufgrund ihrer versteckten Infrastruktur und der schwierigen Überwachung bleiben ihre Leckagen oft in der Anfangsphase unbemerkt. Trotz der umfangreichen technologischen Entwicklung bei den Kanalinspektionsmethoden und den dazugehörigen Techniken ist die Überwachung von Abwasserkanälen auf städtischer Ebene nach wie vor kostspielig und schwierig. Daher werden ein Empfehlungsverfahren und eine Methodenklassifizierung benötigt, um einen nachhaltigen und kosteneffizienten Kanalinspektionsplan auf Stadtebene zu erstellen. In diesem Zusammenhang kann diese Studie im Wesentlichen in drei Teile gegliedert werden. Zunächst wurde eine umfassende Literaturstudie zu den verfügbaren Kanalinspektionsmethoden durchgeführt, um ein umfassenderes Verständnis für deren Wirkungsbereich und technischen Grad zu erhalten. Darüber hinaus wurden diese Inspektionsmethoden auf der Grundlage ihres Wirkungsbereichs in drei Stufen eingeteilt, wobei Stufe 1 die Methoden mit dem größten Wirkungsbereich umfasst, wie z. B. die Verschlechterungsmodellierung, die ein umfassendes und dennoch zuverlässiges Verständnis der Integrität des Abwassersystems ermöglicht. Stufe 2 bietet intermediäre Inspektionsmethoden wie Wärmebildaufnahmen aus der Luft und geoelektrische Inspektionstechniken, die eine zerstörungsfreie Inspektion, der von Stufe 1 vorgeschlagenen Bereiche ermöglichen. Bei den Methoden der Stufe 3 handelt es sich in erster Linie um Inspektionstechniken in der Rohrleitung, die häufig eine Rohrentwässerung erfordern und im Gegenzug für eine hohe Erkennungsgenauigkeit kostspielig zu implementieren sind. Zweitens wurde als Beitrag zu den Tier-1-Methoden das Vulnerability Hotspot Mapping entwickelt, ein GIS-gestütztes Modell, das die am häufigsten von den Entleerungsmodellen verwendeten Faktoren berücksichtigt und Bereiche des Abwassersystems anbietet, die besonders anfällig für Leckagen sind. Die Validierungs- und Sensitivitätsanalysen ergaben, dass die Fließgeschwindigkeit, das Rohralter und die Oberflächenvegetation die sinnvollsten Faktoren für das Modell sind. Darüber hinaus ergab das lineare Modell einen Wirkungsgrad von 76 % und einen mittleren quadratischen Fehler von 0,918, während es durch den Random-Forest-Algorithmus mit 400 Bäumen verbessert wurde, was auf das Potenzial der Schwachstellen-Kartierung als frühzeitige Methode zur Kanalinspektion auf Stadtebene hinweist. Drittens wurden die Tier-2-Methoden aktualisiert, indem das Potenzial der elektrischen Widerstandstomographie und der Mise-la-masse-Techniken als geoelektrische und zerstörungsfreie Methoden hervorgehoben wurde, die experimentell in einem Holzrahmen mit einer Matrix aus Sensoren und Elektroden getestet wurden. Der Versuchsbehälter besteht aus drei Schichten von Elektroden in gesättigten und ungesättigten Zonen, in denen verschiedene Leckageszenarien durchgeführt wurden, um die Sichtbarkeit von Leckagen mit diesen Methoden zu untersuchen. Trotz der Fähigkeit dieser Methoden zur Leckageerkennung wurde festgestellt, dass die elektrische Widerstandstomographie eine höhere Leckageerkennungsempfindlichkeit als die Mise à la masse hat, während sie eine geringere Flexibilität bietet, was ein wichtiger Punkt bei der Methodenauswahl ist. Darüber hinaus wurde festgestellt, dass Mise à-la-masse empfindlicher auf das Vorhandensein von Leckagen reagiert als auf Feuchtigkeits- und Temperaturschwankungen, was zu einem Pearson's r und R2 von 0,8 bzw. 0,7 im Vergleich zu den während der Leckageszenarien gesammelten Daten führte. Insgesamt schlägt diese Studie vor, dass mindestens zwei (vorzugsweise drei) Inspektionstechniken, die zu verschiedenen Ebenen gehören, eingesetzt werden sollten, um einen nachhaltigen Inspektionsplan auf Stadtebene zu haben. Der vorgeschlagene Ansatz hilft dabei, ein Gleichgewicht zwischen Kosten und Präzision sowie ein Gleichgewicht zwischen Zeit und Einwirkungsbereich herzustellen, was einen dezentralisierten und nachhaltigen Inspektionsplan ermöglicht.:List of Abbreviations .......................................................................................... IX List of Peer-Reviewed Publications on the Ph.D. Topic .................................. X List of Co-authored Peer-Reviewed Publications on the Ph.D. Topic ............ X 1 General Introduction........................................................................... 1 1.1 Background ....................................................................................................... 1 1.2 Aim and Objectives .......................................................................................... 3 1.3 Structure of the Document ............................................................................. 3 2 Towards a Decentralized Solution for Sewer Leakage Detection .............................................................................................. 8 2.1 Introduction ...................................................................................................... 10 2.2 Sewer inspection methods (SIMs) overview ................................................. 11 2.2.1 Tier-one (T-I) ................................................................................................................. 11 Deterioration models ....................................................................................................... 12 Hotspot mapping .............................................................................................................. 14 2.2.2 Tier-two (T-II) methods ............................................................................................... 15 Aerial thermal imaging (ATI) ............................................................................................ 15 Ground penetration radar (GPR) .................................................................................... 16 Electrical resistivity tomography (ERT) ........................................................................... 17 Mise-à-la-masse method (MLM)...................................................................................... 18 Soil Sampling ..................................................................................................................... 18 2.2.3 Tier-three (T-III) methods ........................................................................................... 20 General approaches ......................................................................................................... 20 Laser scanning ................................................................................................................... 21 Visual inspection ............................................................................................................... 21 Acoustic methods ............................................................................................................. 22 Ultrasonic inspection ........................................................................................................ 24 Multi-sensor robots .......................................................................................................... 24 Electromagnetic Inspection ............................................................................................. 26 Thermography Inspection ............................................................................................... 26 Tracer Test ......................................................................................................................... 27 VII 2.3 Discussion.......................................................................................................... 30 2.4 Conclusion and outlook ................................................................................... 33 2.5 References ......................................................................................................... 34 3 Vulnerability Hotspot Mapping (VHM) of Sewer Pipes based on Deterioration Factors .................................................................... 42 3.1 Introduction ...................................................................................................... 43 3.2 Materials and Methods.................................................................................... 44 3.2.1 Overview of the sewer deterioration factors. .......................................................... 45 Pipe Age .............................................................................................................................. 46 Pipe Material ...................................................................................................................... 47 Sewer Type ......................................................................................................................... 48 Flow Velocity ...................................................................................................................... 48 Node Degree...................................................................................................................... 49 Surface Vegetation ............................................................................................................ 50 Criticality class and weighting matrix ............................................................................. 50 3.3 Case study ......................................................................................................... 52 3.4 Results and discussions ................................................................................... 54 3.4.1 Network assessment .................................................................................................. 54 3.4.2 Validation and sensitivity analysis ............................................................................ 56 3.5 Summary and conclusion ................................................................................ 61 3.6 Reference........................................................................................................... 63 4 Laboratory Application of the Mise-à-la-Masse (MALM) for Sewer Leakage Detection as an intermediary inspection method. ................................................................................................ 67 4.1 Introduction ...................................................................................................... 68 4.2 Methodology ..................................................................................................... 70 4.2.1 Mise-à-la-Masse method (MALM) .............................................................................. 70 4.2.2 Experimental setup ..................................................................................................... 70 4.2.3 Measurement principles ............................................................................................ 72 4.2.4 Assessed Scenarios ..................................................................................................... 73 4.3 Results and discussions ................................................................................... 74 VIII Inhaltsverzeichnis 4.3.1 Contour Visualization ................................................................................................. 74 First Leakage scenario ...................................................................................................... 74 Other leakage scenarios .................................................................................................. 75 4.3.2 Trend Analyses ............................................................................................................ 77 Leakage proximity ............................................................................................................. 77 Vertical Assessment .......................................................................................................... 78 4.3.3 Data Validation and Sensitivity Analyses ................................................................. 79 Data Validation .................................................................................................................. 79 Sensitivity Analyses ........................................................................................................... 80 4.3.4 Application in practice ................................................................................................ 82 4.4 Summary and Conclusion ............................................................................... 83 4.5 References ......................................................................................................... 85 5 Conclusions and Outlooks .................................................................. 88 5.1 Discussion and Conclusions ............................................................................ 88 5.2 Outlooks ............................................................................................................ 89 6 Supplementary Information ............................................................... 92 / Leaky sewer systems are present in our urbanized world and due to their hidden infrastructure and monitoring challenges, their leakages tend to remain unnoticed often at initial stages. Despite an extensive technological development in sewer inspection methods and their implemented techniques, sewer monitoring at the city scale remains costly and challenging. Therefore, a recommendation procedure and method classification are needed to have a sustainable and cost-effective sewer inspection plan at the city scale. In this context, this study can be mainly divided into three parts. First, an extensive study literature was conducted on available sewer inspection methods to have a wider understanding on their area of impacts and technicality levels, Furthermore, these inspection methods were categorized into three tiers based on their area of impact where Tier-1 consists of largest area of impact methods such as deterioration modelling, which provide a vast yet reliable understanding of the sewer system integrity. Tier-2 offers intermediatory inspection methods such as aerial thermal imagery and geo-electrical inspection techniques, which can provide a non-destructive inspection on areas suggested from Tier-1 techniques. Following the area of impact, Tier-3 methods are mostly in-pipe inspection techniques, which often demand pipe dewatering and are costly to implement in returns of a high detection precision. Second, as a contribution to Tier-1 methods, Vulnerability Hotspot Mapping was developed, which is a GIS-based model according to the most frequently used factors by deterioration models and offers areas of the sewer system more prone to leakage. The validation and sensitivity analyses revealed that flow velocity, pipe age, and surface vegetation are the most sensible factors to the model respectively. Furthermore, the linear model resulted in 76% of efficiency and mean squared error of 0,918 while it was improved with random forest algorithm with 400 trees, which points out the vulnerability mapping potential as an early sewer inspection method at the city scale. Third, Tier-2 methods were updated by emphasizing on the potential of Electrical Resistivity Tomography and Mise à-la-masse techniques as geo-electrical and non-destructive methods, which were experimentally tested within a wooden frame with a matrix of sensors and electrodes implemented. The experimental tank consists of three layers of electrodes in saturated and unsaturated zones, when various leakage scenarios were conducted to investigate on leakage visibility by these methods. Despite the capability of these methods for leakage detection, it was assessed that Electrical Resistivity Tomography has higher leakage detection sensibility than Mise à-la-masse while offering less mobility, which is a considerable point in method selection process. Moreover, it was observed that Mise à-la-masse is more sensitive to leakage presence rather than humidity and temperature variations and resulted in 0.8 and 0.7 in Pearson’s r and R2 respectively in comparison to sampled data during the leakage scenarios. All over, this study suggests that at least two (preferably 3) inspection techniques belonging to different tiers should be implemented to have a sustainable inspection plan at the city scale. The proposed approach helps to have a balance between cost and precision as well as an equilibrium between time and area of impact, which provides a decentralized and sustainable inspection plan.:List of Abbreviations .......................................................................................... IX List of Peer-Reviewed Publications on the Ph.D. Topic .................................. X List of Co-authored Peer-Reviewed Publications on the Ph.D. Topic ............ X 1 General Introduction........................................................................... 1 1.1 Background ....................................................................................................... 1 1.2 Aim and Objectives .......................................................................................... 3 1.3 Structure of the Document ............................................................................. 3 2 Towards a Decentralized Solution for Sewer Leakage Detection .............................................................................................. 8 2.1 Introduction ...................................................................................................... 10 2.2 Sewer inspection methods (SIMs) overview ................................................. 11 2.2.1 Tier-one (T-I) ................................................................................................................. 11 Deterioration models ....................................................................................................... 12 Hotspot mapping .............................................................................................................. 14 2.2.2 Tier-two (T-II) methods ............................................................................................... 15 Aerial thermal imaging (ATI) ............................................................................................ 15 Ground penetration radar (GPR) .................................................................................... 16 Electrical resistivity tomography (ERT) ........................................................................... 17 Mise-à-la-masse method (MLM)...................................................................................... 18 Soil Sampling ..................................................................................................................... 18 2.2.3 Tier-three (T-III) methods ........................................................................................... 20 General approaches ......................................................................................................... 20 Laser scanning ................................................................................................................... 21 Visual inspection ............................................................................................................... 21 Acoustic methods ............................................................................................................. 22 Ultrasonic inspection ........................................................................................................ 24 Multi-sensor robots .......................................................................................................... 24 Electromagnetic Inspection ............................................................................................. 26 Thermography Inspection ............................................................................................... 26 Tracer Test ......................................................................................................................... 27 VII 2.3 Discussion.......................................................................................................... 30 2.4 Conclusion and outlook ................................................................................... 33 2.5 References ......................................................................................................... 34 3 Vulnerability Hotspot Mapping (VHM) of Sewer Pipes based on Deterioration Factors .................................................................... 42 3.1 Introduction ...................................................................................................... 43 3.2 Materials and Methods.................................................................................... 44 3.2.1 Overview of the sewer deterioration factors. .......................................................... 45 Pipe Age .............................................................................................................................. 46 Pipe Material ...................................................................................................................... 47 Sewer Type ......................................................................................................................... 48 Flow Velocity ...................................................................................................................... 48 Node Degree...................................................................................................................... 49 Surface Vegetation ............................................................................................................ 50 Criticality class and weighting matrix ............................................................................. 50 3.3 Case study ......................................................................................................... 52 3.4 Results and discussions ................................................................................... 54 3.4.1 Network assessment .................................................................................................. 54 3.4.2 Validation and sensitivity analysis ............................................................................ 56 3.5 Summary and conclusion ................................................................................ 61 3.6 Reference........................................................................................................... 63 4 Laboratory Application of the Mise-à-la-Masse (MALM) for Sewer Leakage Detection as an intermediary inspection method. ................................................................................................ 67 4.1 Introduction ...................................................................................................... 68 4.2 Methodology ..................................................................................................... 70 4.2.1 Mise-à-la-Masse method (MALM) .............................................................................. 70 4.2.2 Experimental setup ..................................................................................................... 70 4.2.3 Measurement principles ............................................................................................ 72 4.2.4 Assessed Scenarios ..................................................................................................... 73 4.3 Results and discussions ................................................................................... 74 VIII Inhaltsverzeichnis 4.3.1 Contour Visualization ................................................................................................. 74 First Leakage scenario ...................................................................................................... 74 Other leakage scenarios .................................................................................................. 75 4.3.2 Trend Analyses ............................................................................................................ 77 Leakage proximity ............................................................................................................. 77 Vertical Assessment .......................................................................................................... 78 4.3.3 Data Validation and Sensitivity Analyses ................................................................. 79 Data Validation .................................................................................................................. 79 Sensitivity Analyses ........................................................................................................... 80 4.3.4 Application in practice ................................................................................................ 82 4.4 Summary and Conclusion ............................................................................... 83 4.5 References ......................................................................................................... 85 5 Conclusions and Outlooks .................................................................. 88 5.1 Discussion and Conclusions ............................................................................ 88 5.2 Outlooks ............................................................................................................ 89 6 Supplementary Information ............................................................... 92