TY - RPRT A1 - Nastansky, Andreas T1 - Topologische Datenanalyse BT - Eine Einführung in die Persistente Homologie und Mapper T2 - Statistische Diskussionsbeiträge N2 - Bei der Analyse von höherdimensionalen Daten kann deren Gestalt wichtige Informationen über den Datensatz liefern. Bei einer gegebenen Punktwolke, die aus einem unbekannten topologischen Raum ausgewählt wurde, versucht die Topologische Datenanalyse (TDA) den ursprünglichen Raum zu rekonstruieren. Dieser Beitrag soll eine Einführung in die Topologische Datenanalyse geben und konzentriert sich dabei auf zwei wichtige Aspekte: die Persistente Homologie und den Mapper. Dabei werden zuerst die notwendigen theoretischen Grundlagen vorgestellt und anschließend wird die Methodik bei der Visualisierung von Daten eingesetzt. Die Persistente Homologie ist eines der Standardwerkzeuge in der TDA. Sie findet ihre Anwendung beispielsweise in den Bereichen Formerkennung und -beschreibung. Der Mapper als zweites wichtiges Konzept der TDA wandelt umfangreiche, höherdimensionale Datensätze in Simplizialkomplexe um und kann dadurch geometrische und topologische Eigenschaften der Daten bestimmen. Des Weiteren ist die Mapper-Methode ein brauchbares Werkzeug zur Visualisierungen von mehrdimensionalen Daten, woran statistische Verfahren scheitern. N2 - In the analysis of higher-dimensional data their shape can provide important information about the dataset. Given a point cloud sampled from an unknown topological space, topological data analysis tries to reconstruct the original space. This paper provides an introduction into topological data analysis (TDA) and focuses on two important aspects: Persistent Homology and Mapper. First, the theoretical basics are introduced and then the methodology is applied to visualize data. Persistent Homology represents a standard tools in the TDA. This approach is used, for example, in shape recognition and description. The Mapper is a second important concept of the TDA and converts wide, higher-dimensional datasets into simplicial complexes. By that it can determine geometric and topological properties of the data. Furthermore, the Mapper method is a useful tool for the visualization of multi-dimensional data, where statistical methods fail. T3 - Statistische Diskussionsbeiträge - 53 Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-431420 IS - 53 ER - TY - RPRT A1 - Drechsler, Denis T1 - Unemployment in Germany and the Eurosclerosis debate BT - Can the Hartz reforms induce higher employment? N2 - Many European countries have experienced a significant increase of unemployment in recent years. This paper reviews several theoretical models that try to explain this phenomenon. Predominantly, these models claim a link between the poor performance of European labor markets and the high level of market regulation. Commonly referred to as the Eurosclerosis debate, prominent approaches consider insider-outsider relationships, search-models, and the influence of hiring and firing costs on equilibrium employment. The paper presents empirical evidence of each model and studies the relevance of the identified rigidities as a determinant of high unemployment in Europe. Furthermore, a case study analyzes the unemployment problem in Germany and critically discusses new reform efforts. In particular this section analyzes whether the recently enacted Hartz reforms can induce higher employment. T3 - Finanzwissenschaftliche Diskussionsbeiträge - 48 Y1 - 2005 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-9036 ER - TY - RPRT A1 - Borck, Rainald A1 - Schrauth, Philipp T1 - Urban pollution BT - A global perspective T2 - CEPA Discussion Papers N2 - We use worldwide satellite data to analyse how population size and density affect urban pollution. We find that density significantly increases pollution exposure. Looking only at urban areas, we find that population size affects exposure more than density. Moreover, the effect is driven mostly by population commuting to core cities rather than the core city population itself. We analyse heterogeneity by geography and income levels. By and large, the influence of population on pollution is greatest in Asia and middle-income countries. A counterfactual simulation shows that PM2.5 exposure would fall by up to 36% and NO2 exposure up to 53% if within countries population size were equalized across all cities. T3 - CEPA Discussion Papers - 60 KW - population density KW - air pollution KW - gridded data Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-572049 SN - 2628-653X IS - 60 ER - TY - RPRT A1 - Bachelet, Marion A1 - Kalkuhl, Matthias A1 - Koch, Nicolas T1 - What if working from home will stick? BT - Distributional and climate impacts for Germany T2 - CEPA Discussion Papers N2 - The COVID-19 pandemic created the largest experiment in working from home. We study how persistent telework may change energy and transport consumption and costs in Germany to assess the distributional and environmental implications when working from home will stick. Based on data from the German Microcensus and available classifications of working-from-home feasibility for different occupations, we calculate the change in energy consumption and travel to work when 15% of employees work full time from home. Our findings suggest that telework translates into an annual increase in heating energy expenditure of 110 euros per worker and a decrease in transport expenditure of 840 euros per worker. All income groups would gain from telework but high-income workers gain twice as much as low-income workers. The value of time saving is between 1.3 and 6 times greater than the savings from reduced travel costs and almost 9 times higher for high-income workers than low-income workers. The direct effects on CO₂ emissions due to reduced car commuting amount to 4.5 millions tons of CO₂, representing around 3 percent of carbon emissions in the transport sector. T3 - CEPA Discussion Papers - 41 KW - commuting KW - home office KW - COVID-19 KW - energy expenditure KW - carbon emissions Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-532384 SN - 2628-653X IS - 41 ER -