La guerre des irresponsables

Actuellement, le recours aux drones armés fait largement débat. Dans son livre intitulé Théorie du drone, Grégoire Chamayou donne une vue générale de leurs enjeux, contestant la pertinence de l’utilisation d’une telle arme. C’est à partir de son propos, dont je partage pour l’essentiel le contenu, que j’aimerais interroger les manières de penser ces dispositifs. Je commencerai par baliser un terrain connu – l’éthique de la guerre –, avant de proposer certaines inflexions à ce sujet. En mati..

Permutation Flow Shop Scheduling unter Einbezug von Lot Streaming bei auftragsspezifischen Lieferterminvektoren für Due Window-bezogene Zielfunktionen

In dieser Arbeit wird eine Untersuchung vorgestellt zur Aufteilung von Auftragslosen mit mehreren identischen Einheiten in mehrere sog. Sublots, angewandt auf mehrere Liefertermine pro Auftrag. Hierfür werden zwei Zielsetzungen verfolgt, die Minimierung von Terminabweichungen sowie die Minimierung der nicht termingerecht fertiggestellten Menge. Diese Problemstellung wurde bislang in der Literatur nicht untersucht, hat aber praktische Relevanz in allen Fragestellungen, bei denen mehrere identische Einheiten zu fertigen und an verschiedenen Zeitpunkten auszuliefern sind. Die bisherige Forschung hat in den vergangenen knapp fünfzig Jahren die Aufteilung von Auftragslosen intensiv für die Problemstellung einer Minimierung der Gesamtdurchlaufzeit untersucht und hierzu eine Reihe optimierender wie heuristischer Verfahren vorgestellt. Es wurden in dieser Zeit jedoch nur wenige Untersuchungen unter Einbezug von Lieferterminzielsetzungen publiziert, welche zudem alle auf nur einen Liefertermin pro Auftrag ausgelegt waren. Es ist somit die Frage bislang offen geblieben, inwiefern eine Aufteilung von Aufträgen geeignet ist, mehrere Liefertermine pro Auftrag mit geringeren Terminabweichungen zu bedienen. In der vorliegenden Arbeit werden erstmalig auftragsspezifische Lieferterminvektoren und damit verbunden die Zuordnung von Sublots zu diesen Lieferterminen untersucht, angewandt auf Reihenfertigungsprozesse unter Einbezug von Maschinenrüstzeiten. Hierzu wird ein gemischt-ganzzahliges Modell zur Bestimmung der Sublot-Anzahlen sowie ihrer -Größen vorgestellt. Dieses setzt im Rahmen eines zweistufigen Lösungsverfahrens auf einer zuvor bestimmten Zuordnungsmatrix von Auftrags-Sublots in sog. Einlastungspositionen auf den Maschinen auf. Die Bestimmung der Positionen erfolgt zunächst mit Hilfe von Prioritätsregeln und wird durch ein heuristisches Verfahren in Form eines Genetischen Algorithmus anschließend verbessert. Das vorgestellte Verfahren wurde in einer numerischen Untersuchung validiert. In dieser konnte aufgezeigt werden, dass mit steigendem Rüstaufwand mehrere Liefertermine durch ein Sublot bedient werden, während die Zuordnung mehrerer Sublots zu einem Liefertermin abnahm. In allen Testinstanzen führte das Verfahren zu besseren Zielfunktionswerten im Vergleich zu einer Produktion ohne Aufteilung in Teillose. Mit der vorliegenden Arbeit wird die bisherige Forschung zu Lot Streaming um eine neue Richtung erweitert und ein neues Lösungsverfahren vorgestellt.The present thesis introduces a study concerning the splitting of jobs consisting of several identical items into sublots under the assumption of several due windows per job. The two objectives regarded are minimizing the time deviation from due windows and minimizing the number of parts not finished on time. This research question has not been addressed before, but is highly important for any practical situation in which several identical items have to be produced and delivered to customers in various time slots. Previous research within the past fifty years has focused intensively on splitting jobs into sublots to minimize the makespan. Therefore, optimizing and heuristic solution procedures were provided. During this time research involving due dates has received only little attention, which all focused on a single due date per job. Therefore the question remains open if splitting a job into sublots is appropriate to serve several due dates per job to reduce deviations from due dates. This thesis introduces for the first time several due windows per job und investigates the allocation of sublots to due windows, under the assumption of flow shop environments including setups. To achieve this, a mixed integer programming formulation is presented to simultaneously determine sublot number and sizes per job. This approach is based on a two-stage solution method which provides an allocation of job sublots into so-called dispatching positions on the machines in the first stage. The dispatchment of positions is firstly done by using priority rules and afterwards improved by a heuristic procedure based on a Genetic Algorithm. To prove the effectiveness of the proposed method, numerical examples were calculated. These experiments are presented to show that higher setup durations lead to more due windows being served by a single sublot, whereas the number of sublots serving only a single due window diminishes. All of the test instances prove the solution procedure presented in this thesis to be effective to reduce the objective function value compared to a production without using the splitting possibility. The present thesis extends the previously published work on lot streaming to a new research direction which has not been explored before

Zukunfts-Wissen im Diskurs: Eine Didaktik Wissenschaftlicher Weiterbildung für organisationspädagogische Professionalisierung

Wissenschaftliche Weiterbildung ermöglicht die systematische Verknüpfung von Praxis mit Hochschule und bietet zukunftsgestaltende Impulse für Organisationsentwicklung und regionale Nachhaltigkeitsstrategien. Eine diskurs- und zukunftsorientierte Didaktik knüpft makrodidaktisch an Diskursorientierung, Reflexivierung, Zukunfts- und Gestaltungsorientierung an. Mesodidaktisch werden vernetzte Innovationslabore zwischen Hochschule und Region zu geeigneten Organisations- und Wissensformen kollektiver Gestaltungsfähigkeit. Mikrodidaktische Lehr- und Lernarrangements verweisen auf Übergangsfähigkeit, Habitusreflexivität, das Entwerfen sozialer Innovationen und die Entwicklung von Zukunftsstrategien

Understanding Deviations between Spatially Resolved and Homogenized Cathode Models of Lithium‐Ion Batteries

Porous electrode models are essential for inexpensively predicting the performance and lifetime of lithium‐ion batteries. Physics‐based models range from microscopic 3D models, which spatially resolve the microstructural characteristics of all phases in porous electrodes, to reduced and computationally effective models, which do not resolve the microstructure. The homogenized Newman model, also known as the pseudo‐2D (P2D) model, is well established and widely used. However, the necessary simplification shows its weaknesses, especially for high charge and discharge rates, and these lead to significant differences in comparison with the microscopic 3D model. Herein, the validity of the homogenized Newman model is investigated with respect to variations of the microstructural characteristics of a porous cathode. The effects of 1) a homogenized conductive additive; 2) non‐spherical particle geometries; and 3) overlapping particles on charge/discharge curves are analyzed. The result is a better understanding of the validity limits of P2D models. These new insights about the individual influences of the simplifications will be used to improve the homogenized model. The simulation of complex cathode structures, where several homogenization assumptions are violated, shows that the improved homogenized model reaches a very high accuracy, and, thus, overcomes the existing limitations of the P2D model approach

Reward System Dysfunction as a Neural Substrate of Symptom Expression Across the General Population and Patients With Schizophrenia

Dysfunctional patterns of activation in brain reward networks have been suggested as a core element in the pathophysiology of schizophrenia. However, it remains unclear whether this dysfunction is specific to schizophrenia or can be continuously observed across persons with different levels of nonclinical and clinical symptom expression. Therefore, we sought to investigate whether the pattern of reward system dysfunction is consistent with a dimensional or categorical model of psychosis-like symptom expression. 23 patients with schizophrenia and 37 healthy control participants with varying levels of psychosis-like symptoms, separated into 3 groups of low, medium, and high symptom expression underwent event-related functional magnetic resonance imaging while performing a Cued Reinforcement Reaction Time task. We observed lower activation in the ventral striatum during the expectation of high vs no reward to be associated with higher symptom expression across all participants. No significant difference between patients with schizophrenia and healthy participants with high symptom expression was found. However, connectivity between the ventral striatum and the medial orbitofrontal cortex was specifically reduced in patients with schizophrenia. Dysfunctional local activation of the ventral striatum depends less on diagnostic category than on the degree of symptom expression, therefore showing a pattern consistent with a psychosis continuum. In contrast, aberrant connectivity in the reward system is specific to patients with schizophrenia, thereby supporting a categorical view. Thus, the results of the present study provide evidence for both continuous and discontinuous neural substrates of symptom expression across patients with schizophrenia and the general populatio

Structural dynamics in Ni–Fe catalysts during CO₂ methanation - role of iron oxide clusters

Bimetallic Ni–Fe catalysts show great potential for CO$_{2}$ methanation concerning activity, selectivity and long-term stability even under transient reaction conditions as required for Power-to-X applications. Various contrary suggestions on the role of iron in this system on CO$_{2}$ activation have been proposed, hence, its actual task remained still unclear. In this study, we used X-ray absorption spectroscopy (XAS) combined with X-ray diffraction (XRD), XAS in combination with modulation excitation spectroscopy (MES) and density functional theory (DFT) to shed detailed light on the role of iron in a bimetallic Ni–Fe based CO$_{2}$ methanation catalyst. During catalyst activation we observed a synergistic effect between nickel and iron that led to higher fractions of reduced nickel compared to a monometallic Ni-based catalyst. By XAS–XRD combined with DFT, we found formation of FeO$_{x}$ clusters on top of the metal particles. Modulation excitation coupled XAS data complemented with DFT calculations provided evidence of a Fe$^{0}$ ⇌ Fe$^{2+}$+ ⇌ Fe$^{3+}$ redox mechanism at the interface of these FeO$_{x}$ clusters. This may promote CO$_{2}$ dissociation. This is the first time that this highly dynamic role of iron has been experimentally confirmed in bimetallic Ni–Fe based catalysts with respect to CO$_{2}$ activation during the methanation reaction and may also be at the origin of better performance of other CO$_{2}$-hydrogenation catalysts. The insight into the structural surface changes reported in this study show the dynamics of the Fe–Ni system and allow the development of realistic surface models as basis for CO$_{2}$ activation and possible intermediates in these bimetallic systems