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Decision support in international long-haul freight transportation for the planning of rest periods, breaks and vehicle refueling
Full text linkIn international long-haul freight transportation, truck drivers are often on the road for several consecutive days or even weeks. During their trips, they must comply with the rules on driving time, breaks and rest periods which in the European Union are governed by Regulation (EC) No 561/2006. As the regulation has a high influence on the transport durations, it has to be taken into account when planning arrival times at customer locations and choosing among multiple customer time windows. Considering transport costs, a high attention should be paid to fuel costs as fuel is one main cost driver in the road haulage sector. An analysis of diesel price variations across different European countries showed that a significant potential for cutting fuel expenditure can be found in international long-haul freight transportation. Thus, fuel costs and driver rest periods and breaks are two important issues that transport companies have to take into account to be profitable
Resolving Leads in Sea-Ice Models : New Analysis Methods for Frontier Resolution Arctic Simulations
Full text linkSea ice deforms constantly under the forcing of winds and ocean currents. Eventually the ice cover of the Arctic Ocean breaks into a multitude of ice floes. Strips of open ocean, so-called leads, and pressure ridges, where the collision of floes piled up the ice, are found along the floe boundaries. These features have a strong impact on the interaction of sea ice with the atmosphere and the ocean, as they affect heat loss and surface drag. Currently, climate models do not resolve leads and pressure ridges in simulated sea ice fields due to their coarse resolution. They parameterize the effects of leads on the Arctic climate, if at all. The goal of this thesis is to develop Arctic simulations that reproduce leads sufficiently to be used in climate simulations. By decreasing the horizontal grid-spacing, a numerical ocean sea-ice model is shown to resolve leads explicitly. To test how realistic these lead-resolving sea-ice simulations are, the following research questions are addressed: (1) what are good metrics to evaluate the simulated leads with observational data? (2) Which observed characteristics of sea ice deformation and deformation features are reproduced by the model? In a first step, the sea ice deformation in a 1-km lead-resolving sea-ice simulation is analyzed with a spatio-temporal scaling analysis. The simulated sea ice deformation is strongly localized in failure zones and dominated by spontaneous fracture. This heterogeneity and intermittency of sea ice deformation shows that the simulation captures the fracture processes that form leads. In a second step, two new algorithms are described that detect and track leads and pressure ridges, combined into Linear Kinematic Features (LKFs). Both algorithms are applied to deformation data observed from satellite to establish a data set of deformation features that can be used as a reference in model evaluation. LKFs in two lead-resolving sea-ice simulations are extracted with the same algorithms, and found to agree with the LKF data set with respect to their spatial characteristics and temporal evolutions. In conclusion, high resolution sea-ice simulations can explicitly resolve leads. These simulations reproduce the characteristics of sea ice deformation and the representation of LKFs that are both observed from satellite. In future work, these simulations could be used as prototypes for the configuration of the sea-ice component in a climate model to directly simulate air-ice-ocean interaction processes in the Arctic
Stakeholderbasierte Ermittlung und Auswahl von Nachhaltigkeitsindikatoren : Fallstudie und Systemaufstellung in einem Unternehmen der Bio-Lebensmittelbranche
Full text linkCompanies face challenges where traditional management models are increasingly reaching their limits. This is particularly evident in the conflicting goals that arise from the socio-cultural and political sustainability debate, because companies operate in a field of conflicts between social responsibility, ecological awareness and economic success. Reference Points are given by multidimensional reporting guidelines, which require the disclosure of standardized performance criteria based on generally applicable indicators. This work comprises a participatory process for the stakeholder-based determination and selection of sustainability indicators for the implementation of a sustainability strategy for the purpose of sustainable corporate management. The implementation of a sustainability target system also serves as the basis for the preparation of sustainability reporting and certification. The entire procedure is based on the G4-guidelines of the GRI and is reflected in a classic project completion analysis and an organizational constellation
Knowledge transfer, transitional dynamics and optimal Research & Development policy in a dynamic monopoly setting
Full text linkThis paper focuses on the question whether or not a reduction of the knowledge barrier is good for welfare. Based on a dynamic monopoly setting with simultaneous investment decisions in process as well as in product Research & Development (R&D), we show that a reduction of the knowledge barrier has ambiguous welfare consequences: Due to a lower knowledge barrier, product quality and welfare increase in the short-run. However, this may not necessarily be the case in the long-run. One reason is that a positive long-lasting knowledge barrier shock triggers the monopolist to sub-optimally lower its product R&D investments today and in the future at the cost of future product quality. This in turn may reduce welfare. Accordingly, to realize the first-best level of product quality, the long-run optimal R&D subsidy rate for product innovations increase with a reduction of the knowledge barrier
Le differenti memorie della guerra in Jugoslavia (1991-1995) nel romanzo europeo occidentale in prospettiva transnazionale
No full textThe present doctoral thesis is an analysis of novels about the war in Yugoslavia from 1995 to 2015 from a transnational perspective The literary corpus comprises 13 novels, written in Italian, German, Spanish and published in French. Based on Erll and Nünning's definition of memory in literature , the memory of the Yugoslavian war in contemporary novels is examined. The three macro themes of Gender and Generations , Violence and Literature and Memory, Media and Propaganda will be elaborated and deepened. ---------------------------- La tesi di dottorato analizzata un corpus letterario composto da tredici romanzi scritti in francese (1), spagnolo (2), tedesco (4) e italiano (6), anche da autori provenienti dalla ex-Jugoslavia. Partendo dalla definizione di Erll e Nünning Gedächtnis in der Literatur si sviluppa uno studio sulla memoria della guerra in Jugoslavia (1991-1995) nel romanzo contemporaneo di alcuni paesi dell'Europa occidentale. L'analisi letteraria dei testi letterari approfondisce tre macrotemi centrali: generi e generazioni , violenza e letteratura , e memoria, media e propaganda . ----------- Bei der vorliegenden Doktorarbeit handelt es sich um eine Analyse von Romanen über den Jugoslawienkrieg aus den Jahren 1995 bis 2015 aus einer transnationalen Perspektive. Der literarische Korpus umfasst 13 Romane, die auf italienisch, deutsch, spanisch und französisch veröffentlicht wurden. Ausgehend von der Definition Gedächtnis in der Literatur von Erll und Nünning wird die Erinnerung an den Jugoslawienkrieg im Gegenwartsromanen untersucht. Hierbei werden die drei Makrothemen Gender und Generationen , Gewalt und Literatur sowie Gedächtnis, Medien und Propaganda herausgearbeitet und vertieft
Transitioning towards sustainability : practices and outcomes in European and West African ports
Full text linkThe dissertation analyses the transitioning of the port sector towards sustainability in environmental and social terms. In specific, it explores how port authorities in Europe and West Africa engage with the globalising green port idea, and what role is played by contextual factors in determining the choice of policy measures and technological tools they adopt or implement in their different contexts. The dissertation further examines the extent to which sustainability-oriented port network(ing) bring to bear positive influence on sustainability practices of participating ports (authorities) and facilitates environmental upgrading along the maritime value chain. Finally, it interrogates outcomes of stakeholder-inclusive port development discourses and mechanisms. It does this by combining concepts and theories such as policy mobilities, sustainability fix and critical debates on network theory and network governance. Methodologically, the dissertation draws on information collected through a triangulation of qualitative research methods and document analysis. The findings show that sustainability schemes and green initiatives of ports are crucially 'translocal', and draws attention to contested outcomes in port networks and stakeholder-inclusive initiatives and discourses of ports
Causes for variable hydrothermal vent fluid compositions in intraoceanic arcs : insights from fluid compositions and mineral precipitates of the South Kermadec Arc
Full text linkThis work presents investigations of high-T hydrothermal vent fluids, associated mineral precipitates and volcanic rocks from three submarine volcanos in the South Kermadec intraoceanic arc (Brothers Caldera, Haungaroa Volcano, Macauley Caldera). Mineralogical investigations, vent fluid compositions and fluid inclusion studies are discussed. Reaction path models simulate the influence of host rock compositions and the integrated fluid flux on the formation of massive sulfides. Further models demonstrate how addition of magmatic SO2 to hydrothermal systems generates arc typical magmatic-hydrothermal fluids and influences their REE composition. Vent fluid compositions, as well as salinities and formation temperatures in mineral precipitates from seawater-dominated hydrothermal fluids, point to boiling processes of rising solutions. The investigations demonstrate how magma degassing and boiling are key processes responsible for the chemical diversity of arc hydrothermal fluids
Digitale Nomaden in der Arbeitswelt von morgen : ein Lebenskonzept zwischen Vision und Illusion
Full text linkIn vorliegender Arbeit wird das Phänomen des digitalen Nomadismus dargestellt, welches sich innerhalb der letzten Jahre rasant entwickelt hat und bislang in weiten Teilen als nicht ausreichend erforscht bewertet werden kann. Das Lebenskonzept der Digitalen Nomaden, welches sich im Kern durch örtliche Ungebundenheit und die Erwerbstätigkeit im digitalen Raum auszeichnet, bietet die Möglichkeit aus dem konservativen Entwurf des Normalarbeitsverhältnisses auszubrechen und neue Wege zu beschreiten. Das weitverbreitete Image des Lebensstils verspricht ein glückliches Leben in Freiheit und Selbstbestimmung, jedoch bleibt die Frage, ob diese Vorstellung der Realität entspricht zunächst offen. Die Auswertung von leitfadengestützten Interviews, die im Rahmen der vorliegenden Arbeit mit Digitalen Nomaden geführt wurden, gibt Aufschluss darüber, ob sich die Erwartungen derjenigen erfüllen, die sich für das multiflexible Lebenskonzept entschieden haben, welche Schwierigkeiten aus dem Lebensstil resultieren und ob er als langfristige Lebensart bewertet werden kann
Functional Role of Critical Dynamics in Flexible Visual Information Processing
Full text linkRecent experimental and theoretical work has established the hypothesis that cortical neurons operate close to a critical state which signifies a phase transition from chaotic to ordered dynamics. Critical dynamics are suggested to optimize several aspects of neuronal information processing. However, although signatures of critical dynamics have been demonstrated in recordings of spontaneously active cortical neurons, little is known about how these dynamics are affected by task-dependent changes in neuronal activity when the cortex is engaged in stimulus processing. In fact, some in vivo investigations of the awake and active cortex report either an absence of signatures of criticality or relatively weak ones. In addition, the functional role of criticality in optimizing computation is often reported in abstract theoretical studies, adopting minimalistic models with homogeneous topology and slowly-driven networks. Consequently, there is a lack of concrete links between information theoretical benefits of the critical state and neuronal networks performing a behaviourally relevant task. In this thesis we explore such concrete links by focusing on the visual system, which needs to meet major computational challenges on a daily basis. Among others, the visual system is responsible for the rapid integration of relevant information from a large number of single channels, and in a flexible manner depending on the behavioral and environmental contexts. We postulate that critical neuronal dynamics in the form of cascades of activity spanning large populations of neurons may support such quick and complex computations. Specifically, we consider two notable examples of well-known phenomena in visual information processing: First the enhancement of object discriminability under selective attention, and second, a feature integration and figure-ground segregation scenario. In the first example, we model the top-down modulation of the activity of visuocortical neurons in order to selectively improve the processing of an attended region in a visual scene. In the second example, we model how neuronal activity may be modulated in a bottom-up fashion by the properties of the visual stimulus itself, which makes it possible to perceive different shapes and objects. We find in both scenarios that the task performance may be improved by employing critical networks. In addition, we suggest that the specific task- or stimulus-dependent modulations of information processing may be optimally supported by the tuning of relevant local neuronal networks towards or away from the critical point. Thus, the relevance of this dissertation is summarized by the following points: We formally extend the existing models of criticality to inhomogeneous systems subject to a strong external drive. We present concrete functional benefits for networks operating near the critical point in well-known experimental paradigms. Importantly, we find emergent critical dynamics only in the parts of the network which are processing the behaviourally relevant information. We suggest that the implied locality of critical dynamics in space and time may help explain why some studies report no signatures of criticality in the active cortex
