Performance Evaluation of Vision-Based Algorithms for MAVs

An important focus of current research in the field of Micro Aerial Vehicles (MAVs) is to increase the safety of their operation in general unstructured environments. Especially indoors, where GPS cannot be used for localization, reliable algorithms for localization and mapping of the environment are necessary in order to keep an MAV airborne safely. In this paper, we compare vision-based real-time capable methods for localization and mapping and point out their strengths and weaknesses. Additionally, we describe algorithms for state estimation, control and navigation, which use the localization and mapping results of our vision-based algorithms as input.Comment: Presented at OAGM Workshop, 2015 (arXiv:1505.01065

Catastrophe management: riverine flooding

Losses from natural disasters are on the rise and risk management options for lessening direct as well as indirect consequences are gaining in importance. Riverine flooding is one key concern and climate change is globally projected to increase intensity and frequency of flooding burden - albeit, due to numerous uncertainties there is only low confidence in projected changes. On the other hand, there is high confidence that today's and future losses are rising as more assets and people are moving in harm's way. The quantitative assessment of flood risk is complex, as such extreme event risk is characterized by few observations (low probability) associated with massive consequences (hihg impact), which by definition means substantial uncertainty around any estimates, particularly if future drivers, such as from climate change, need to be addressed as well. The methodology of choice is probabilistic catastrophe modelling, which combines hazard (flood intensity and frequency) with exposure (people and assets) and their vulnerability (susceptibility of exposed people and assets to incur losses for a given hazard). In order to properly account for uncertainty, we present three different catastrophe risk modelling approaches that outline the scope for possible changes in flood risk in Austria over the next 90 years. The analysis and findings are particularly relevant for Austria's Natural Disaster Fund, which is the primary disater loss financing vehicle in Austria. Large uncertainties between the different approaches and various limitations restrict our general conclusion as well as a full comparison between the approaches. However, we discuss possibilities to overcome these barriers in the future including suggestions how to arrive at more robust solutions in the face of such large uncertainties

Automated End-to-End Workflow for Precise and Geo-accurate Reconstructions using Fiducial Markers

Photogrammetric computer vision systems have been well established in many scientific and commercial fields during the last decades. Recent developments in image-based 3D reconstruction systems in conjunction with the availability of affordable high quality digital consumer grade cameras have resulted in an easy way of creating visually appealing 3D models. However, many of these methods require manual steps in the processing chain and for many photogrammetric applications such as mapping, recurrent topographic surveys or architectural and archaeological 3D documentations, high accuracy in a geo-coordinate system is required which often cannot be guaranteed. Hence, in this paper we present and advocate a fully automated end-to-end workflow for precise and geoaccurate 3D reconstructions using fiducial markers. We integrate an automatic camera calibration and georeferencing method into our image-based reconstruction pipeline based on binary-coded fiducial markers as artificial, individually identifiable landmarks in the scene. Additionally, we facilitate the use of these markers in conjunction with known ground control points (GCP) in the bundle adjustment, and use an online feedback method that allows assessment of the final reconstruction quality in terms of image overlap, ground sampling distance (GSD) and completeness, and thus provides flexibility to adopt the image acquisition strategy already during image recording. An extensive set of experiments is presented which demonstrate the accuracy benefits to obtain a highly accurate and geographically aligned reconstruction with an absolute point position uncertainty of about 1.5 times the ground sampling distance

Catastrophic Risk and Egalitarian Principles for Risk Transfer Mechanisms

Financial aid for the worst off victims of earthquakes and other catastrophes seems tobe a morally unquestioned principle for the allocation of public funds. This paper shows however, that this principle is ambiguous if the decision is viewed as a dynamic choice problem where such resources need to be allocated in two periods: before and after the event takes place (before and after uncertainty is resolved). The literature on social choice suggests that utilitarian principles fare better in such situations. This paper provides a uniform formal framework to relate one such result, namely a multi-profile version of Harsanyis 1955 theorem by Mongin (1994) to another one by Myerson (1981), stated in a somewhat unconventional social choice framework. It shows that the Linearity condition, that is met only by welfare functions of the utilitarian type, has a natural interpretation in terms of an equivalence of ex ante and ex post evaluation, a concept that is related to but not equivalent with dynamic consistency

Qualitative insights into the effect on travel behavior of joining a carshare

Carsharing organizations (carshares) provide collectively available vehicles that can be booked for exclusive use on a pay-as-you-go basis. Previous research has shown that two groups join carshares: (a) accessors, who do not have a car when they join the carshare and therefore gain access to one, and (b) shedders, who give up a car when they join the carshare. The paper examines the circumstances and motivations that cause accessors and shedders to join a carshare, the changes in their travel behavior in the short and longer run, and how the travel behavior might have changed if the carshare had not been joined. These objectives were achieved through in-depth interviews with 16 members of a carshare in Bath, United Kingdom. The interviewed members were selected to achieve a mix of accessors, shedders, recent members, and longstanding members. It was found that carshare attracted people who were already contemplating giving up their cars or who had been triggered by life events to consider giving up their cars. Joining a carshare prevented the acquisition of cars for some members, but some subsequently took opportunities to acquire a car as their circumstances changed. Once shedders became members, they adapted to managing without a personal car, used a variety of transport modes, planned their activity-travel schedules in advance, and took into account the costs and convenience of different options. The increasing popularity of new mobility options, such as carsharing, also has implications for the methods used to analyze and model travel behavior. The option of joining a carshare and using carshare vehicles should be included in transport models for areas in which carshares operate

Climate-induced changes on the hydrology of mediterranean basins - a research concept to reduce uncertainty and quantify risk

The presented project initiative CLIMB ('Climate Induced Changes on the Hydrology of Mediterranean Basins Reducing Uncertainty and Quantifying Risk') has recently signed a Grant Agreement in EC's 7th Framework Program (FP7-ENV.2009.1.1.5.2). In its 4-year design, starting from January 2010, the collaborative project for specific cooperation actions (SICA) dedicated to international partner countries shall analyze ongoing and future climate-induced changes in hydrological budgets and extremes across the Mediterranean and neighboring regions. This is undertaken in study sites located in Sardinia, Northern Italy, Southern France, Tunisia, Turkey, Egypt and the Palestinian-administered area Gaza. The work plan is targeted to selected river or aquifer catchments, where the consortium will employ a combination of novel field monitoring and remote sensing concepts, data assimilation, integrated hydrologic modeling and socioeconomic factor analyses to reduce existing uncertainties in climate change impact analysis. Advanced climate scenario analysis will be employed and available ensembles of regional climate model simulations will be downscaled. This process will provide the drivers for an ensemble of hydro(-geo)logical models with different degrees of complexity in terms of process description and level of integration. The results of hydrological modeling and socio-economic factor analysis will enable the development of a GIS-based Vulnerability and Risk Assessment Tool. This tool will serve as a platform for the dissemination of project results, including communication with and planning for local and regional stakeholders. An important output of the research in the individual study sites will be the development of a set of recommendations for an improved monitoring and modeling strategy for climate change impact assessment. CLIMB is forming a cluster of independent projects with WASSERMed from the Environment and CLICO from Socio-Economic Sciences and Humanities Call of FP7 in 2009 (see Fig. 2). The intention of this clustering is to foster scientific synergy and cooperation between the partner projects to achieve improvements in policy outreach on different spatial scales

Changements induits par le climat sur l'hydrologie des bassins Méditerranéens : un concept de recherche pour réduire les incertitudes et quantifier les risques

International audienceThe presented project initiative CLIMB (Climate Induced Changes on the Hydrology of Mediterranean Basins Reducing Uncertainty and Quantifying Risk) has recently signed a Grant Agreement in EC's 7th Framework Program (FP7-ENV.2009.1.1.5.2). In its 4-year design, starting from January 2010, the collaborative project for specific cooperation actions (SICA) dedicated to international partner countries shall analyze ongoing and future climate-induced changes in hydrological budgets and extremes across the Mediterranean and neighboring regions. This is undertaken in study sites located in Sardinia, Northern Italy, Southern France, Tunisia, Turkey, Egypt and the Palestinian-administered area Gaza. The work plan is targeted to selected river or aquifer catchments, where the consortium will employ a combination of novel field monitoring and remote sensing concepts, data assimilation, integrated hydrologic modeling and socioeconomic factor analyses to reduce existing uncertainties in climate change impact analysis. Advanced climate scenario analysis will be employed and available ensembles of regional climate model simulations will be downscaled. This process will provide the drivers for an ensemble of hydro(-geo)logical models with different degrees of complexity in terms of process description and level of integration. The results of hydrological modeling and socio-economic factor analysis will enable the development of a GIS-based Vulnerability and Risk Assessment Tool. This tool will serve as a platform for the dissemination of project results, including communication with and planning for local and regional stakeholders. An important output of the research in the individual study sites will be the development of a set of recommendations for an improved monitoring and modeling strategy for climate change impact assessment. CLIMB is forming a cluster of independent projects with WASSERMed from the Environment and CLICO from Socio-Economic Sciences and Humanities Call of FP7 in 2009 (see Fig. 2). The intention of this clustering is to foster scientific synergy and cooperation between the partner projects to achieve improvements in policy outreach on different spatial scales.Le projet FP7 CLIMB (Climate Induced Changes on the Hydrology of Mediterranean Basins Reducing Uncertainty and Quantifying Risk) (FP7-ENV.2009.1.1.5.2), d'une durée de 4 ans, avec un démarrage en janvier 2010 a pour objectif d'analyser l'impact du changement climatique sur l'hydrologie des bassins Méditerranéens. Des sites d'études en Italie, France (bassin de Thau), Tunisie, Turquie, Egypte et la bande de Gaza seront étudiés. Le consortium va employer des techniques nouvelles de télédétection et de géophysique, d'assimilation de données, de modélisation hydrologique et une analyse de facteurs socio économiques pour réduire les incertitudes dans les modèles et analyser l'impact du changement climatique