TY - JOUR A1 - Daviter, Falk T1 - Coping, taming or solving BT - alternative approaches to the governance of wicked problems JF - Policy studies N2 - One of the truisms of policy analysis is that policy problems are rarely solved. As an ever-increasing number of policy issues are identified as an inherently ill-structured and intractable type of wicked problem, the question of what policy analysis sets out to accomplish has emerged as more central than ever. If solving wicked problems is beyond reach, research on wicked problems needs to provide a clearer understanding of the alternatives. The article identifies and explicates three distinguishable strategies of problem governance: coping, taming and solving. It shows that their intellectual premises and practical implications clearly contrast in core respects. The article argues that none of the identified strategies of problem governance is invariably more suitable for dealing with wicked problems. Rather than advocate for some universally applicable approach to the governance of wicked problems, the article asks under what conditions different ways of governing wicked problems are analytically reasonable and normatively justified. It concludes that a more systematic assessment of alternative approaches of problem governance requires a reorientation of the debate away from the conception of wicked problems as a singular type toward the more focused analysis of different dimensions of problem wickedness. KW - Wicked problems KW - complex problems KW - governance KW - problem-solving KW - policy analysis Y1 - 2017 U6 - https://doi.org/10.1080/01442872.2017.1384543 SN - 0144-2872 SN - 1470-1006 VL - 38 IS - 6 SP - 571 EP - 588 PB - Routledge, Taylor & Francis Group CY - Abingdon ER - TY - GEN A1 - Kühn, Michael A1 - Schöne, Tim T1 - Multivariate regression model from water level and production rate time series for the geothermal reservoir Waiwera (New Zealand) T2 - Energy procedia N2 - Water management tools are necessary to guarantee the preservation of natural resources while ensuring optimum utilization. Linear regression models are a simple and quick solution for creating prognostic capabilities. Multivariate models show higher precision than univariate models. In the case of Waiwera, implementation of individual production rates is more accurate than applying just the total production rate. A maximum of approximately 1,075 m3/day can be pumped to ensure a water level of at least 0.5 m a.s.l. in the monitoring well. The model should be renewed annually to implement new data and current water level trends to keep the quality. KW - geothermal reservoir KW - water management KW - data based model KW - multivariate regression KW - coefficient of determination KW - scenario analysis Y1 - 2017 U6 - https://doi.org/10.1016/j.egypro.2017.08.196 SN - 1876-6102 VL - 125 SP - 571 EP - 579 PB - Elsevier CY - Amsterdam ER - TY - GEN A1 - Wetzel, Maria A1 - Kempka, Thomas A1 - Kühn, Michael T1 - Predicting macroscopic elastic rock properties requires detailed information on microstructure T2 - Energy procedia N2 - Predicting variations in macroscopic mechanical rock behaviour due to microstructural changes, driven by mineral precipitation and dissolution is necessary to couple chemo-mechanical processes in geological subsurface simulations. We apply 3D numerical homogenization models to estimate Young’s moduli for five synthetic microstructures, and successfully validate our results for comparable geometries with the analytical Mori-Tanaka approach. Further, we demonstrate that considering specific rock microstructures is of paramount importance, since calculated elastic properties may deviate by up to 230 % for the same mineral composition. Moreover, agreement between simulated and experimentally determined Young’s moduli is significantly improved, when detailed spatial information are employed. KW - digital rock physics KW - effective elastic properties KW - numerical Y1 - 2017 U6 - https://doi.org/10.1016/j.egypro.2017.08.195 SN - 1876-6102 VL - 125 SP - 561 EP - 570 PB - Elsevier CY - Amsterdam ER - TY - GEN A1 - Kühn, Michael A1 - Li, Qi A1 - Nakaten, Natalie Christine A1 - Kempka, Thomas T1 - Integrated subsurface gas storage of CO2 and CH4 offers capacity and state-of-the-art technology for energy storage in China T2 - Energy procedia N2 - Integration and development of the energy supply in China and worldwide is a challenge for the years to come. The innovative idea presented here is based on an extension of the “power-to-gas-to-power” technology by establishing a closed carbon cycle. It is an implementation of a low-carbon energy system based on carbon dioxide capture and storage (CCS) to store and reuse wind and solar energy. The Chenjiacun storage project in China compares well with the German case study for the towns Potsdam and Brandenburg/Havel in the Federal State of Brandenburg based on the Ketzin pilot site for CCS. KW - gas storage KW - carbon dioxide KW - methane KW - hydrogen KW - renewable energy KW - carbon cycle Y1 - 2017 U6 - https://doi.org/10.1016/j.egypro.2017.08.039 SN - 1876-6102 VL - 125 SP - 14 EP - 18 PB - Elsevier CY - Amsterdam ER - TY - GEN A1 - Kühn, Michael A1 - Kempka, Thomas A1 - de Lucia, Marco A1 - Scheck-Wenderoth, Magdalena T1 - Dissolved CO2 storage in geological formations with low pressure, low risk and large capacities T2 - Energy procedia N2 - Geological CO2 storage is a mitigation technology to reduce CO2 emissions from fossil fuel combustion. However, major concerns are the pressure increase and saltwater displacement in the mainly targeted deep groundwater aquifers due to injection of supercritical CO2. The suggested solution is storage of CO2 exclusively in the dissolved state. In our exemplary regional case study of the North East German Basin based on a highly resolved temperature and pressure distribution model and a newly developed reactive transport coupling, we have quantified that 4.7 Gt of CO2 can be stored in solution compared to 1.5 Gt in the supercritical state. KW - carbon dioxide KW - dissolved KW - storage capacity KW - numerical simulation KW - saline aquifer KW - Buntsandstein Y1 - 2017 U6 - https://doi.org/10.1016/j.egypro.2017.03.1607 SN - 1876-6102 VL - 114 SP - 4722 EP - 4727 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Pyšek, Petr A1 - Pergl, Jan A1 - Essl, Franz A1 - Lenzner, Bernd A1 - Dawson, Wayne A1 - Kreft, Holger A1 - Weigelt, Patrick A1 - Winter, Marten A1 - Kartesz, John A1 - Nishino, Misako A1 - Antonova, Liubov A. A1 - Barcelona, Julie F. A1 - Cabezas, Francisco José A1 - Cárdenas López, Dairon A1 - Cárdenas-Toro, Juliana A1 - Castańo, Nicolás A1 - Chacón, Eduardo A1 - Chatelain, Cyrille A1 - Dullinger, Stefan A1 - Ebel, Aleksandr L. A1 - Figueiredo, Estrela A1 - Fuentes, Nicol A1 - Genovesi, Piero A1 - Groom, Quentin J. A1 - Henderson, Lesley A1 - Inderjit, A1 - Kupriyanov, Andrey A1 - Masciadri, Silvana A1 - Maurel, Noëlie A1 - Meerman, Jan A1 - Morozova, Olʹga V. A1 - Moser, Dietmar A1 - Nickrent, Daniel A1 - Nowak, Pauline M. A1 - Pagad, Shyama A1 - Patzelt, Annette A1 - Pelser, Pieter B. A1 - Seebens, Hanno A1 - Shu, Wen-sheng A1 - Thomas, Jacob A1 - Velayos, Mauricio A1 - Weber, Ewald A1 - Wieringa, Jan J. A1 - Baptiste, Maria P. A1 - Kleunen, Mark van T1 - Naturalized alien flora of the world T1 - Naturalizovaná nepůvodní flóra světa BT - species diversity, taxonomic and phylogenetic patterns, geographic distribution and global hotspots of plant invasion BT - druhová diverzita, taxonomické a fylogenetické složení, geografické zákonitosti a globální ohniska rostlinných invazí JF - Preslia : the journal of the Czech Botanical Society N2 - Using the recently built Global Naturalized Alien Flora (GloNAF) database, containing data on the distribution of naturalized alien plants in 483 mainland and 361 island regions of the world, we describe patterns in diversity and geographic distribution of naturalized and invasive plant species, taxonomic, phylogenetic and life-history structure of the global naturalized flora as well as levels of naturalization and their determinants. The mainland regions with the highest numbers of naturalized aliens are some Australian states (with New South Wales being the richest on this continent) and several North American regions (of which California with 1753 naturalized plant species represents the world’s richest region in terms of naturalized alien vascular plants). England, Japan, New Zealand and the Hawaiian archipelago harbour most naturalized plants among islands or island groups. These regions also form the main hotspots of the regional levels of naturalization, measured as the percentage of naturalized aliens in the total flora of the region. Such hotspots of relative naturalized species richness appear on both the western and eastern coasts of North America, in north-western Europe, South Africa, south-eastern Australia, New Zealand, and India. High levels of island invasions by naturalized plants are concentrated in the Pacific, but also occur on individual islands across all oceans. The numbers of naturalized species are closely correlated with those of native species, with a stronger correlation and steeper increase for islands than mainland regions, indicating a greater vulnerability of islands to invasion by species that become successfully naturalized. South Africa, India, California, Cuba, Florida, Queensland and Japan have the highest numbers of invasive species. Regions in temperate and tropical zonobiomes harbour in total 9036 and 6774 naturalized species, respectively, followed by 3280 species naturalized in the Mediterranean zonobiome, 3057 in the subtropical zonobiome and 321 in the Arctic. The New World is richer in naturalized alien plants, with 9905 species compared to 7923 recorded in the Old World. While isolation is the key factor driving the level of naturalization on islands, zonobiomes differing in climatic regimes, and socioeconomy represented by per capita GDP, are central for mainland regions. The 11 most widely distributed species each occur in regions covering about one third of the globe or more in terms of the number of regions where they are naturalized and at least 35% of the Earth’s land surface in terms of those regions’ areas, with the most widely distributed species Sonchus oleraceus occuring in 48% of the regions that cover 42% of the world area. Other widely distributed species are Ricinus communis, Oxalis corniculata, Portulaca oleracea, Eleusine indica, Chenopodium album, Capsella bursa-pastoris, Stellaria media, Bidens pilosa, Datura stramonium and Echinochloa crus-galli. Using the occurrence as invasive rather than only naturalized yields a different ranking, with Lantana camara (120 regions out of 349 for which data on invasive status are known), Calotropis procera (118), Eichhornia crassipes (113), Sonchus oleraceus (108) and Leucaena leucocephala (103) on top. As to the life-history spectra, islands harbour more naturalized woody species (34.4%) thanmainland regions (29.5%), and fewer annual herbs (18.7% compared to 22.3%). Ranking families by their absolute numbers of naturalized species reveals that Compositae (1343 species), Poaceae (1267) and Leguminosae (1189) contribute most to the global naturalized alien flora. Some families are disproportionally represented by naturalized aliens on islands (Arecaceae, Araceae, Acanthaceae, Amaryllidaceae, Asparagaceae, Convolvulaceae, Rubiaceae, Malvaceae), and much fewer so on mainland (e.g. Brassicaceae, Caryophyllaceae, Boraginaceae). Relating the numbers of naturalized species in a family to its total global richness shows that some of the large species-rich families are over-represented among naturalized aliens (e.g. Poaceae, Leguminosae, Rosaceae, Amaranthaceae, Pinaceae), some under-represented (e.g. Euphorbiaceae, Rubiaceae), whereas the one richest in naturalized species, Compositae, reaches a value expected from its global species richness. Significant phylogenetic signal indicates that families with an increased potential of their species to naturalize are not distributed randomly on the evolutionary tree. Solanum (112 species), Euphorbia (108) and Carex (106) are the genera richest in terms of naturalized species; over-represented on islands are Cotoneaster, Juncus, Eucalyptus, Salix, Hypericum, Geranium and Persicaria, while those relatively richer in naturalized species on the mainland are Atriplex, Opuntia, Oenothera, Artemisia, Vicia, Galium and Rosa. The data presented in this paper also point to where information is lacking and set priorities for future data collection. The GloNAF database has potential for designing concerted action to fill such data gaps, and provide a basis for allocating resources most efficiently towards better understanding and management of plant invasions worldwide. KW - alien species KW - distribution KW - Global Naturalized Alien Flora (GloNAF) database KW - invasive species KW - islands KW - life history KW - mainland KW - naturalized species KW - phylogeny KW - plant invasion KW - regional floras KW - species richness KW - taxonomy KW - zonobiome Y1 - 2017 U6 - https://doi.org/10.23855/preslia.2017.203 SN - 0032-7786 VL - 89 IS - 3 SP - 203 EP - 274 PB - Czech Botanical Soc. CY - Praha ER - TY - GEN A1 - Plauth, Max A1 - Sterz, Christoph A1 - Eberhardt, Felix A1 - Feinbube, Frank A1 - Polze, Andreas T1 - Assessing NUMA performance based on hardware event counters T2 - IEEE International Parallel and Distributed Processing Symposium Workshops (IPDPSW) N2 - Cost models play an important role for the efficient implementation of software systems. These models can be embedded in operating systems and execution environments to optimize execution at run time. Even though non-uniform memory access (NUMA) architectures are dominating today's server landscape, there is still a lack of parallel cost models that represent NUMA system sufficiently. Therefore, the existing NUMA models are analyzed, and a two-step performance assessment strategy is proposed that incorporates low-level hardware counters as performance indicators. To support the two-step strategy, multiple tools are developed, all accumulating and enriching specific hardware event counter information, to explore, measure, and visualize these low-overhead performance indicators. The tools are showcased and discussed alongside specific experiments in the realm of performance assessment. KW - Parallel programming KW - Performance analysis KW - Memory management Y1 - 2017 SN - 978-0-7695-6149-3 U6 - https://doi.org/10.1109/IPDPSW.2017.51 SN - 2164-7062 SP - 904 EP - 913 PB - Institute of Electrical and Electronics Engineers CY - New York ER - TY - GEN A1 - Torkura, Kennedy A. A1 - Sukmana, Muhammad Ihsan Haikal A1 - Cheng, Feng A1 - Meinel, Christoph T1 - Leveraging cloud native design patterns for security-as-a-service applications T2 - IEEE International Conference on Smart Cloud (SmartCloud) N2 - This paper discusses a new approach for designing and deploying Security-as-a-Service (SecaaS) applications using cloud native design patterns. Current SecaaS approaches do not efficiently handle the increasing threats to computer systems and applications. For example, requests for security assessments drastically increase after a high-risk security vulnerability is disclosed. In such scenarios, SecaaS applications are unable to dynamically scale to serve requests. A root cause of this challenge is employment of architectures not specifically fitted to cloud environments. Cloud native design patterns resolve this challenge by enabling certain properties e.g. massive scalability and resiliency via the combination of microservice patterns and cloud-focused design patterns. However adopting these patterns is a complex process, during which several security issues are introduced. In this work, we investigate these security issues, we redesign and deploy a monolithic SecaaS application using cloud native design patterns while considering appropriate, layered security counter-measures i.e. at the application and cloud networking layer. Our prototype implementation out-performs traditional, monolithic applications with an average Scanner Time of 6 minutes, without compromising security. Our approach can be employed for designing secure, scalable and performant SecaaS applications that effectively handle unexpected increase in security assessment requests. KW - Cloud-Security KW - Security-as-a-Service KW - Vulnerability Assessment KW - Cloud Native Applications Y1 - 2017 SN - 978-1-5386-3684-8 U6 - https://doi.org/10.1109/SmartCloud.2017.21 SP - 90 EP - 97 PB - Institute of Electrical and Electronics Engineers CY - New York ER - TY - JOUR A1 - Ette, Ottmar T1 - Welterleben/Weiterleben BT - On Vectopia in Georg Forster, Alexander von Humboldt, and Adelbert von Chamisso JF - Daphnis : Zeitschrift für mittlere deutsche Literatur N2 - Welterleben and Weiterleben are what determine the second globalization (of four previously explored) whose constantly accelerating dynamic, vectorization, this essay explores. On the basis of selected writings of Georg Forster, Alexander von Humboldt, and Adelbert von Chamisso, the author highlights the increasing speed with which knowledge, especially in the experiential sciences, is produced and disseminated following the routes of ever-widening trade speeded along by globalization. The notion of ‘vectopia’ stands for the connection of utopia and uchronia in space and time in such a way that the experience of the world, expanded worldwide, contains within it a Weiter-Leben, a ‘living-further’ that is to be understood first in a spatial, and not yet temporal, sense, of what Forster called Erfahrungswissen, or ‘experiential knowledge.’ Vectopia, as elaborated here, has a material dimension that relates to the physical person, the body, the experience of the world that cannot occur without the constant changing of place, without a journeying that is again and again recommenced. Vectopia develops the projection of a life not from space or from time alone, but by their combination. Vectopia is more than a concept, it is a thought-figure: it is vitally connected to life, and thus a life-figure. It opens itself to a type of knowledge that stands almost at the threshold of a further life, indeed, of a Weiterleben that, opening itself to a ‘living-onward,’ resides beyond space, time, and movement. KW - travel literature KW - transdisciplinary KW - accelerated globalization KW - experiential knowledge KW - Weiter-Leben Y1 - 2017 U6 - https://doi.org/10.1163/18796583-04503002 SN - 0300-693X SN - 1879-6583 VL - 45 IS - 3-4 SP - 343 EP - 388 PB - Editions Rodopi BV CY - Amsterdam ER - TY - GEN A1 - Limberger, Daniel A1 - Scheibel, Willy A1 - Trapp, Matthias A1 - Döllner, Jürgen Roland Friedrich T1 - Mixed-projection treemaps BT - a novel approach mixing 2D and 2.5D treemaps T2 - 21st International Conference Information Visualisation (IV) N2 - This paper presents a novel technique for combining 2D and 2.5D treemaps using multi-perspective views to leverage the advantages of both treemap types. It enables a new form of overview+detail visualization for tree-structured data and contributes new concepts for real-time rendering of and interaction with treemaps. The technique operates by tilting the graphical elements representing inner nodes using affine transformations and animated state transitions. We explain how to mix orthogonal and perspective projections within a single treemap. Finally, we show application examples that benefit from the reduced interaction overhead. KW - Information Visualization KW - Overview plus Detail KW - Treemaps KW - 2.5D Treemaps KW - Multi-perspective Views Y1 - 2017 SN - 978-1-5386-0831-9 U6 - https://doi.org/10.1109/iV.2017.67 SN - 2375-0138 SP - 164 EP - 169 PB - Institute of Electrical and Electronics Engineers CY - Los Alamitos ER -