Invariance of fluid limits for the Shortest Remaining Processing Time and Shortest Job First policies

We consider a single-server queue with renewal arrivals and i.i.d. service times, in which the server employs either the preemptive Shortest Remaining Processing Time (SRPT) policy, or its non-preemptive variant, Shortest Job First (SJF). We show that for given stochastic primitives (initial condition, arrival and service processes), the model has the same fluid limit under either policy. In particular, we conclude that the well-known queue length optimality of preemptive SRPT is also achieved, asymptotically on fluid scale, by the simpler-to-implement SJF policy. We also conclude that on fluid scale, SJF and SRPT achieve the same performance with respect to response times of the longest-waiting jobs in the system.Comment: 24 page

Coping with Requirements Uncertainty: An Interpretive Case Study

Information systems development projects (ISDPs) often face requirements uncertainty. Thus, coping with this issue is an important project management task in ISDPs. In order to gain insights into which different requirements uncertainty situations exist and how to cope with them, we conducted a longitudinal interpretive case study. We investigated the requirements analysis of an ISDP in an international insurance company for 17 months. Thereby, we identified eight distinct requirements uncertainty situation types, observed ten requirements engineering (RE) techniques applied in practice and their impact on requirements uncertainty situation types, and finally derived recommendations for applying RE techniques in requirements uncertainty situations based on our observations. We combine these findings and contribute to RE literature by making a first step towards a framework for coping with requirements uncertainty in ISDPs. We believe that RE researchers as well as practitioners in ISDPs can make use of this article’s insights

Geschichte und Theorie der abgestuften Integration Europas

Die aktuelle "Euro-Krise" hat viele Europapolitiker dazu veranlasst, die bisherigen Integra- tionsstrategien der Europäischen Union verstärkt in Frage zu stellen. Mit Schlagwörtern wie "Kerneuropa" oder "Europa der zwei Geschwindigkeiten" wird zunehmend über die Etablierung alternativer, abgestufter Integrationsmethoden nachgedacht. So argumentiert selbst José Manuel Barroso im September 2011, die dringend notwendigen wirtschaft- und währungspolitischen Reformen der Europäisch en Union könnten angesichts der Blockadehaltung einiger Mitgliedstaaten nur auf dem Wege der abgestuften Integration umgesetzt werden. Die aktuelle Brisanz dieser Debatte und die steigende Anzahl der Forderungen nach einem abgestuften Europa werden hier zum Anlass genommen, um der Frage nachzugehen, welche Erfahrungen die EU bereits mit der Anwendung abgestufter Integrationsstrategien hat. Was bedeutet überhaupt die Rede von einem „Kerneuropa“ oder einem „Europa der zwei Geschwindigkeiten“ und welche politischen Konzepte wurden in diesem Bereich bisher entwickelt? Ein historischer Überblick über die Ideen einer abgestuften Integration Europas zeigt zunächst, dass diese Strategien keineswegs neu sind, sondern schon seit Beginn der Integrationsentwicklung von verschiedenen politischen Akteuren entwickelt wurden. Im empirischen Teil des Papers wird anschließend die Frage diskutiert, inwieweit diese Ideen im Laufe der europäischen Integration bereits verwirklicht wurden. Der Versuch, die Entstehung von abgestuften Integrationsideen und -strukturen theoretisch zu erklären, schließt das Paper ab.The current "Euro-Crisis" caused many European politicians to challenge the common strategy of European integration. They consider new strategies, such as the method of differentiated integration. In reference to the continuous vetos of some member states, even José Manuel Barroso argued in September 2011 that the European Union can realise the sorely needed politico-economic reforms in the way of differentiated integration only. In the light of this debate it seems vital to analyze the history and the theory of differentiated integration in this essay. The essay intends to show what it means, when European politicians talk about "Kerneuropa" (Core Europe) or "Europa der zwei Geschwindigkeiten" (Two-paced Europe). A historical overview will evidence that these ideas of a differentiated integration are not new but have indeed been present from the very beginning of the development of the European Communities. Subsequently, the paper will explore the empirical question whether these ideas have ever been realised. The conclusion of this paper will attempt to provide a theoretical explanation of the development of these ideas and structures of differentiated integration in the European history

Towards Mindful Case Study Research in IS: A Critical Analysis of the Past Ten Years

Case study research (CSR) has gained strong acceptance in information systems (IS) research in the recent decades. This article examines how CSR has been used in IS research practice. Contrasting the currently used CSR approaches to methodological prescriptions can lead to recommendations for researchers applying this research strategy as well as to advances in the methodological literature. Our study design comprises two steps. First, we identified case studies published in six major IS journals from 2001 to 2010. Second, we critically examined CSR practices in the identified studies. We observed a dualism, as CSR currently consists of a positivist and an equally strong interpretive research stream. Case studies with other philosophical underpinnings were rarely found. We describe the CSR practice and contrast it to the methodological prescriptions. Thereby, we clearly point out the shortcomings, aiming to initiate a debate on how our community should further develop its use of CSR to become more mindful. This study is the first broad examination of CSR in IS (focusing on more than just the positivist research stream) and thus contributes to the methodological literature by providing recommendations for improvements

Experimental and Theoretical Identification of the Origin of Magnetic Anisotropy in Intermediate Spin Iron(III) Complexes

The complexes [(FeLX)-X-N2S2] [in which L-N2S2 = 2,2'-(2,2'-bipryridine-6,6'-diyl)bis(1,1'-diphenylethanethiolate) and X = Cl, Br and I], characterized crystallographically earlier and here (Fe(L)Br), reveal a square pyramidal coordinated Fe-III ion. Unusually, all three complexes have intermediate spin ground states. Susceptibility measurements, powder cw X- and Q-band EPR spectra, and zero-field powder Mossbauer spectra show that all complexes display distinct magnetic anisotropy, which has been rationalized by DFT calculations.Supplementary material: [http://cherry.chem.bg.ac.rs/handle/123456789/3204

Coherence and transparency: some advice for qualitative researchers

This is an Open Access Article. It is published by Brazilian Association of Production Engineering (ABEPRO) under the Creative Commons Attribution 4.0 International Licence (CC BY). Full details of this licence are available at: http://creativecommons.org/licenses/by/4.0/There is relatively little advice in the Engineering domain for undertaking qualitative studies. Researchers have to rely on generic guidance that may result in imprecise application of qualitative methods. A related discipline to Engineering is Information Systems (IS) and the experiences of the IS domain may provide some useful insights for undertaking qualitative studies. This paper synthesizes the guidance from the IS community for crafting high quality qualitative studies and manuscripts. It reports on five themes: i) Establishing philosophical underpinnings; ii) Clarifying theoretical aims; iii) Selecting qualitative methods; iv) Demonstrating rigour in qualitative data analysis; and v) Grappling with generalisation. The review stresses the importance of coherence and transparency for crafting qualitative research manuscripts and provides a list of reflective questions for qualitative research design

New perspectives on rare connective tissue calcifying diseases

Connective tissue calcifying diseases (CTCs) are characterized by abnormal calcium deposition in connective tissues. CTCs are caused by multiple factors including chronic diseases (Type II diabetes mellitus, chronic kidney disease), the use of pharmaceuticals (e.g. warfarin, glucocorticoids) and inherited rare genetic diseases such as pseudoxanthoma elasticum (PXE), generalized arterial calcification in infancy (GACI) and Keutel syndrome (KTLS). This review explores our current knowledge of these rare inherited CTCs, and highlights the most promising avenues for pharmaceutical intervention. Advancing our understanding of rare inherited forms of CTC is not only essential for the development of therapeutic strategies for patients suffering from these diseases, but also fundamental to delineating the mechanisms underpinning acquired chronic forms of CTC

Psychologie in Testen und Testing-Mindset: Oder warum Entwickler und Tester sich (manchmal) nicht verstehen

Haben Sie sich schon mal gefragt, wie es um die Kommunikation in Ihrem Team zwischen Software Entwicklern und Software Testern steht und wie diese verbessert werden kann? Beide sprechen quasi ihre eigene Sprache und die jeweiligen Mitarbeiter weisen bestimmte Merkmale auf, seien sie nun wirklich charakterlich nachweisbar oder im Denkprozess anderer Beteiligter vorhanden. Einige Unstimmigkeiten basieren auf Missverständnissen zwischen den beiden Gruppen und ihren Tätigkeiten. Mit diesem Vortrag sollen Möglichkeiten für ein besseres Verständnis und ein besseres Miteinander bewusst werden, sodass die Zusammenarbeit künftig noch besser und reibungsloser funktioniert. Dabei wird die Zusammenarbeit von beiden Seiten beleuchtet – und trotz der unterschiedlichen Anforderungen eine gemeinsame Basis herausgearbeitet und aufgezeigt. Themen, auf die eingegangen wird sind unter anderem das Mindset und der Umgang mit und die Reaktion auf Testergebnisse, sowie Mitarbeiterqualifikationen

Über die Zweckmässigkeit in der Natur bei Schopenhauer

von Otto KeutelProgr.-Nr. 57