TY - JOUR A1 - Schlosser, Rainer A1 - Walther, Carsten A1 - Boissier, Martin A1 - Uflacker, Matthias T1 - Automated repricing and ordering strategies in competitive markets JF - AI communications : AICOM ; the European journal on artificial intelligence N2 - Merchants on modern e-commerce platforms face a highly competitive environment. They compete against each other using automated dynamic pricing and ordering strategies. Successfully managing both inventory levels as well as offer prices is a challenging task as (i) demand is uncertain, (ii) competitors strategically interact, and (iii) optimized pricing and ordering decisions are mutually dependent. We show how to derive optimized data-driven pricing and ordering strategies which are based on demand learning techniques and efficient dynamic optimization models. We verify the superior performance of our self-adaptive strategies by comparing them to different rule-based as well as data-driven strategies in duopoly and oligopoly settings. Further, to study and to optimize joint dynamic ordering and pricing strategies on online marketplaces, we built an interactive simulation platform. To be both flexible and scalable, the platform has a microservice-based architecture and allows handling dozens of competing merchants and streams of consumers with configurable characteristics. KW - Dynamic pricing KW - inventory management KW - demand learning KW - oligopoly competition KW - e-commerce Y1 - 2019 U6 - https://doi.org/10.3233/AIC-180603 SN - 0921-7126 SN - 1875-8452 VL - 32 IS - 1 SP - 15 EP - 29 PB - IOS Press CY - Amsterdam ER - TY - JOUR A1 - Krummenauer, Linda A1 - Prahl, Boris F. A1 - Costa, Luís Fílípe Carvalho da A1 - Holsten, Anne A1 - Walther, Carsten A1 - Kropp, Jürgen T1 - Global drivers of minimum mortality temperatures in cities JF - The science of the total environment : an international journal for scientific research into the environment and its relationship with man N2 - Human mortality shows a pronounced temperature dependence. The minimum mortality temperature (MMT) as a characteristic point of the temperature-mortality relationship is influenced by many factors. As MMT estimates are based on case studies, they are sporadic, limited to data-rich regions, and their drivers have not yet been clearly identified across case studies. This impedes the elaboration of spatially comprehensive impact studies on heat-related mortality and hampers the temporal transfer required to assess climate change impacts. Using 400 MMTs from cities, we systematically establish a generalised model that is able to estimate MMTs (in daily apparent temperature) for cities, based on a set of climatic, topographic and socio-economic drivers. A sigmoid model prevailed against alternative model setups due to having the lowest Akaike Information Criterion (AICc) and the smallest RMSE. We find the long-term climate, the elevation, and the socio-economy to be relevant drivers of our MMT sample within the non-linear parametric regression model. A first model application estimated MMTs for 599 European cities ( >100 000 inhabitants) and reveals a pronounced decrease in MMTs (27.8-16 degrees C) from southern to northern cities. Disruptions of this pattern across regions of similar mean temperatures can be explained by socio-economic standards as noted for central eastern Europe. Our alternative method allows to approximate MMTs independently from the availability of daily mortality records. For the first time, a quantification of climatic and non-climatic MMT drivers has been achieved, which allows to consider changes in socio-economic conditions and climate. This work contributes to the comparability among MMTs beyond location-specific and regional limits and, hence, towards a spatially comprehensive impact assessment for heat-related mortality. KW - City population KW - Minimum mortality temperature KW - Climate KW - Topography KW - Socio-economy KW - Sigmoid model Y1 - 2019 U6 - https://doi.org/10.1016/j.scitotenv.2019.07.366 SN - 0048-9697 SN - 1879-1026 VL - 695 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Gudipudi, Venkata Ramana A1 - Fluschnik, Till A1 - Ros, Anselmo Garcia Cantu A1 - Walther, Carsten A1 - Kropp, Jürgen T1 - City density and CO2 efficiency JF - Energy policy : the international journal of the political, economic, planning, environmental and social aspects of energy N2 - Cities play a vital role in the global climate change mitigation agenda. City population density is one of the key factors that influence urban energy consumption and the subsequent GHG emissions. However, previous research on the relationship between population density and GHG emissions led to contradictory results due to urban/rural definition conundrum and the varying methodologies for estimating GHG emissions. This work addresses these ambiguities by employing the City Clustering Algorithm (CCA) and utilizing the gridded CO2 emissions data. Our results, derived from the analysis of all inhabited areas in the US, show a sub-linear relationship between population density and the total emissions (i.e. the sum of on-road and building emissions) on a per capita basis. Accordingly, we find that doubling the population density would entail a reduction in the total CO2 emissions in buildings and on-road sectors typically by at least 42%. Moreover, we find that population density exerts a higher influence on on-road emissions than buildings emissions. From an energy consumption point of view, our results suggest that on-going urban sprawl will lead to an increase in on-road energy consumption in cities and therefore stresses the importance of developing adequate local policy measures to limit urban sprawl. (C) 2016 Elsevier Ltd. All rights reserved. KW - Population density KW - City boundaries KW - Urban energy KW - Sectoral emissions KW - Urban sprawl Y1 - 2016 U6 - https://doi.org/10.1016/j.enpol.2016.01.015 SN - 0301-4215 SN - 1873-6777 VL - 91 SP - 352 EP - 361 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Olonscheck, Mady A1 - Walther, Carsten A1 - Lüdeke, Matthias K. B. A1 - Kropp, Jürgen T1 - Feasibility of energy reduction targets under climate change: The case of the residential heating energy sector of the Netherlands JF - Energy N2 - In order to achieve meaningful climate protection targets at the global scale, each country is called to set national energy policies aimed at reducing energy consumption and carbon emissions. By calculating the monthly heating energy demand of dwellings in the Netherlands, our case study country, we contrast the results with the corresponding aspired national targets. Considering different future population scenarios, renovation measures and temperature variations, we show that a near zero energy demand in 2050 could only be reached with very ambitious renovation measures. While the goal of reducing the energy demand of the building sector by 50% until 2030 compared to 1990 seems feasible for most provinces and months in the minimum scenario, it is impossible in our scenario with more pessimistic yet still realistic assumptions regarding future developments. Compared to the current value, the annual renovation rate per province would need to be at least doubled in order to reach the 2030 target independent of reasonable climatic and population changes in the future. Our findings also underline the importance of policy measures as the annual renovation rate is a key influencing factor regarding the reduction of the heating energy demand in dwellings. (C) 2015 Elsevier Ltd. All rights reserved. KW - Climate change KW - Heating energy demand KW - Reduction targets KW - Residential building stock KW - Renovation KW - The Netherlands Y1 - 2015 U6 - https://doi.org/10.1016/j.energy.2015.07.080 SN - 0360-5442 SN - 1873-6785 VL - 90 SP - 560 EP - 569 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Klein, Daniel R. A1 - Olonscheck, Mady A1 - Walther, Carsten A1 - Kropp, Jürgen T1 - Susceptibility of the European electricity sector to climate change JF - Energy N2 - The electricity system is particularly susceptible to climate change due to the close interconnectedness between electricity production, consumption and climate. This study provides a country based relative analysis of 21 European countries' electricity system susceptibility to climate change. Taking into account 14 quantitative influencing factors, the susceptibility of each country is examined both for the current and projected system with the result being a relative ranked index. Luxembourg and Greece are the most susceptible relatively due in part to their inability to meet their own electricity consumption demand with inland production, and the fact that the majority of their production is from more susceptible sources, primarily combustible fuels. Greece experiences relatively warm mean temperatures, which are expected to increase in the future leading to greater summer electricity consumption, increasing susceptibility. Norway was found to be the least susceptible, relatively, due to its consistent production surplus, which is primarily from hydro (a less susceptible source) and a likely decrease of winter electricity consumption as temperatures rise due to climate change. The findings of this study enable countries to identify the main factors that increase their electricity system susceptibility and proceed with adaptation measures that are the most effective in decreasing susceptibility. KW - Thermal electricity production KW - Energy security KW - Heating and cooling electricity consumption KW - Vulnerability KW - Air conditioners KW - Electricity generation by source Y1 - 2013 U6 - https://doi.org/10.1016/j.energy.2013.06.048 SN - 0360-5442 VL - 59 IS - 6 SP - 183 EP - 193 PB - Elsevier CY - Oxford ER -