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See detailStrategic Safety Stock Placement in Supply Networks with Static Dual Supply
Klosterhalfen, Steffen UL; Minner, Stefan; Willems, Sean

in Manufacturing & Service Operations Management (2014), 16(2), 204-219

Many real-world supply networks source required materials from multiple suppliers. Existing multiechelon inventory optimization approaches either restrict their scope to multiple supply sources in two ... [more ▼]

Many real-world supply networks source required materials from multiple suppliers. Existing multiechelon inventory optimization approaches either restrict their scope to multiple supply sources in two-echelon systems or single suppliers in multiechelon systems. We develop an exact mathematical model for static dual supply in a general acyclic N-echelon network structure, which builds on the guaranteed-service framework for safety stock optimization. It is assumed that the suppliers are allocated static fractions of demand. We prove that for normally distributed demand an extreme point property holds. We present a real example from the industrial electronics industry consisting of five echelons and three dual-sourced materials. This example forms the basis for a numerical analysis. Compared with the only previously published approximate solution, our exact approach results in considerable cost savings because the exact model captures inventory pooling in a way that the approximation is unable to do. For a set of test problems, total safety stock cost savings are 9.1%, on average. [less ▲]

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See detailRail Car Fleet Design: Optimization of Structure and Size
Klosterhalfen, Steffen UL; Kallrath, J.; Fischer, G.

in International Journal of Production Economics (2014), 157

We develop a model to determine the optimal structure and size of a rail car fleet at a chemical company under uncertainty in demand and travel times as well as substitution between rail car types. First ... [more ▼]

We develop a model to determine the optimal structure and size of a rail car fleet at a chemical company under uncertainty in demand and travel times as well as substitution between rail car types. First, we formulate an MILP model that accounts for the substitution relations between the types and minimizes the total direct rail car cost under given rail car availability constraints and a predefined maximum number of types. Second, based on the fleet structure obtained by the MILP model, the fleet size is computed by using an approximation from inventory theory that considers the existing uncertainties. Compared to the current approach of the rail car fleet management team, the model produces a reduction in safety stock of 120 rail cars and thus direct cost savings of 8% as well as further indirect cost savings due to a smaller number of rail car types, which reduces the switching effort of the rail cars on the storage tracks. [less ▲]

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See detailInvited talk - Schulübergangsentscheidung in Luxemburg
Krolak-Schwerdt, Sabine UL

Conference given outside the academic context (2013)

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See detailDiscussant - Session 5
Krolak-Schwerdt, Sabine UL

Scientific Conference (2013, November)

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See detailPanel discussion - Challenges in measuring methodology
Cao, Li; Fox, Jean-Paul; Hambleton, Ronald K. et al

Scientific Conference (2013, November)

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See detailInvited talk - Diagnostische Kompetenzen
Gräsel, Cornelia; Krolak-Schwerdt, Sabine UL

Scientific Conference (2013, October)

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See detailTeacher judgment accuracy
Krolak-Schwerdt, Sabine UL

Scientific Conference (2013, July)

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See detailThe owl of Minerva flies only at dusk? British diplomacy on the eve of Yugoslav wars
Glaurdic, Josip UL

in East European Politics & Societies (2013), 27(3), 545-563

Could the Western foreign policy makers have done anything to prevent the violence accompanying the breakup of Yugoslavia? The answer to that question largely depends on their level of awareness of what ... [more ▼]

Could the Western foreign policy makers have done anything to prevent the violence accompanying the breakup of Yugoslavia? The answer to that question largely depends on their level of awareness of what was happening in the South Slavic federation in the run-up to war. This article analyzes a string of newly declassified documents of the British Foreign Office related to the February 1991 visit of a high-level British political delegation to Yugoslavia, together with interviews with some of the meetings’ protagonists. These declassified documents and interviews offer a unique snapshot in the development of the Yugoslav crisis and Britain’s policy in the region. They give us a clear picture of the goals and strategies of the principal Yugoslav players and show us what the West knew about the true nature of the Yugoslav crisis and when. The article’s conclusions are clear. Yugoslavia’s breakup and impending violence did not require great foresight. Their cause was known well in advance because it was preannounced— it was the plan of the Serbian regime of Slobodan Milošević to impose a centralized Yugoslavia upon the other republics or, if that failed, to use force to create a Greater Serbia on Yugoslavia’s ruins. Crucially, British policy at the time did nothing to dissuade Milošević from his plan and likely contributed to his confidence in using violence to pursue the creation of a new and enlarged Serbian state. [less ▲]

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See detailInvited talk - TRANSINTER - erste Ergebnisse und zukünftige Pläne
Pit, Ineke UL; Glock, Sabine; Krolak-Schwerdt, Sabine UL

Conference given outside the academic context (2013)

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See detailVicarious pain while observing another in pain: an experimental approach.
Vandenbroucke, S.; Crombez, G.; van Ryckeghem, Dimitri UL et al

in Frontiers in human neuroscience (2013), 7

OBJECTIVE: This study aimed at developing an experimental paradigm to assess vicarious pain experiences. We further explored the putative moderating role of observer's characteristics such as ... [more ▼]

OBJECTIVE: This study aimed at developing an experimental paradigm to assess vicarious pain experiences. We further explored the putative moderating role of observer's characteristics such as hypervigilance for pain and dispositional empathy. METHODS: Two experiments are reported using a similar procedure. Undergraduate students were selected based upon whether they reported vicarious pain in daily life, and categorized into a pain responder group or a comparison group. Participants were presented a series of videos showing hands being pricked whilst receiving occasionally pricking (electrocutaneous) stimuli themselves. In congruent trials, pricking and visual stimuli were applied to the same spatial location. In incongruent trials, pricking and visual stimuli were in the opposite spatial location. Participants were required to report on which location they felt a pricking sensation. Of primary interest was the effect of viewing another in pain upon vicarious pain errors, i.e., the number of trials in which an illusionary sensation was reported. Furthermore, we explored the effect of individual differences in hypervigilance to pain, dispositional empathy and the rubber hand illusion (RHI) upon vicarious pain errors. RESULTS: RESULTS of both experiments indicated that the number of vicarious pain errors was overall low. In line with expectations, the number of vicarious pain errors was higher in the pain responder group than in the comparison group. Self-reported hypervigilance for pain lowered the probability of reporting vicarious pain errors in the pain responder group, but dispositional empathy and the RHI did not. CONCLUSION: Our paradigm allows measuring vicarious pain experiences in students. However, the prevalence of vicarious experiences of pain is low, and only a small percentage of participants display the phenomenon. It remains however unknown which variables affect its occurrence. [less ▲]

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See detailThe predictive value of attentional bias towards pain-related information in chronic pain patients: a diary study.
van Ryckeghem, Dimitri UL; Crombez, Geert; Goubert, Liesbet et al

in Pain (2013), 154(3), 468-75

Theoretical accounts of chronic pain hypothesize that attentional bias towards pain-related information is a maintaining or exacerbating factor, fuelling further pain, disability, and distress. However ... [more ▼]

Theoretical accounts of chronic pain hypothesize that attentional bias towards pain-related information is a maintaining or exacerbating factor, fuelling further pain, disability, and distress. However, empirical research testing this idea is currently lacking. In the present study, we investigated whether attentional bias towards pain-related information predicts daily pain-related outcomes in a sample of chronic pain patients (n=69; M(age)=49.64 years; 46 females). During an initial laboratory session, attentional bias to pain-related information was assessed using a modified spatial cueing task. In advance, patients completed a number of self-report measures assessing current pain intensity, current disability, and pain duration. Subsequently, daily pain outcomes (self-reported pain severity, disability, avoidance behaviour, and distractibility) were measured for 2 weeks by means of an electronic diary. Results indicated that, although an attentional bias towards pain-related information was associated with the current level of disability and pain severity, it had no additional value above control variables in predicting daily pain severity, avoidance, distractibility, and disability. Attentional bias towards pain-related information did, however, moderate the relationship between daily pain severity and both daily disability and distractibility, indicating that, particularly in those patients with a strong attentional bias, increases in pain were associated with increased disability and distractibility. The use of interventions that diminish attentional bias may therefore be helpful to reduce daily disability and the level of distraction from current tasks despite the presence of pain in chronic pain patients. [less ▲]

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See detailAttentional bias to pain-related information: a meta-analysis.
Crombez, Geert; van Ryckeghem, Dimitri UL; Eccleston, Christopher et al

in Pain (2013), 154(4), 497-510

This meta-analysis investigated whether attentional bias, that is, the preferential allocation of attention to information that is related to pain, is a ubiquitous phenomenon. We also investigated whether ... [more ▼]

This meta-analysis investigated whether attentional bias, that is, the preferential allocation of attention to information that is related to pain, is a ubiquitous phenomenon. We also investigated whether attentional bias effects are related to the methodological quality of the study, to procedural differences in their measurement, or to individual differences in pain severity, pain-related fear, anxiety, and depression. Results indicated that individuals who experience chronic pain (n=1023) display an attentional bias towards pain-related words or pictures, but this bias was of a small effect size (d=0.134), and did not differ from that in control groups (d=0.082; n=1398). No evidence was found for an attentional bias towards pain-related words and pictures for acute pain (d=0.049), procedural pain (d=0.142), and experimental pain (d=0.069). However, research in which attentional bias towards signals of impending experimental pain in healthy volunteers was investigated, revealed an attentional bias of medium effect size (d=0.676). Moderator analyses in the chronic pain group identified important procedural variables that affected the presence and magnitude of an attentional bias towards pain-related words and pictures, that is, type and exposure time of pain-related information. None of the individual difference variables affected the magnitude of the attentional bias. Implications of current findings and future directions are discussed. [less ▲]

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See detailOdgovor na prikaz knjige Vrijeme Europe
Glaurdic, Josip UL

in Casopis za Suvremenu Povijest (2013), 44(3), 747-754

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