Not All Explanations Predict Satisfactorily, and Not All Good Predictions Explain

This short comment on Epstein's (2008) paper and on the response by Thompson and Derr argues that the symmetry between explanation and prediction cannot satisfactorily be discussed without making clear what prediction means - depending on which connotations the authors have with 'prediction' their arguments can or cannot be accepted.[No keywords]

The Development of Social Simulation as Reflected in the First Ten Years of JASSS: a Citation and Co-Citation Analysis

Social simulation is often described as a multidisciplinary and fast-moving field. This can make it difficult to obtain an overview of the field both for contributing researchers and for outsiders who are interested in social simulation. The Journal for Artificial Societies and Social Simulation (JASSS) completing its tenth year provides a good opportunity to take stock of what happened over this time period. First, we use citation analysis to identify the most influential publications and to verify characteristics of social simulation such as its multidisciplinary nature. Then, we perform a co-citation analysis to visualize the intellectual structure of social simulation and its development. Overall, the analysis shows social simulation both in its early stage and during its first steps towards becoming a more differentiated discipline.Citation Analysis, Co-Citation Analysis, Lines of Research, Multidisciplinary, Science Studies, Social Simulation

Epistemological Perspectives on Simulation

This special section includes papers originally presented at a workshop on \'Epistemological Perspectives on Simulation\' in July 2004 at the University of Koblenz, in which some thirty colleagues participated. It had been our impression that there was (and still is) a small, but growing number of researchers who are interested in investigating the preconditions of successfully deploying simulation as a research tool. We were convinced that discussing the epistemological status of simulation in a cross-disciplinary setting could contribute to a deeper understanding of relevant issues and so it proved.Simulation, Epistemology, Methodology

Epistemological Perspectives on Simulation. An Introduction

LNAI Book Serie

Netzfehler in vermaschten HGÜ-Netzen: ein Verfahren zur Berechnung, Detektion, Fehlerklärung

Weltweit wird der Aufbau von Energieübertragungsnetzen basierend auf Hochspannungsgleichstromübertragung (HGÜ) diskutiert. Eine mögliche Anwendung ist der Transport verbraucherfern regenerativ erzeugter Energie in die Lastzentren, wodurch bestehende Drehstromübertragungssysteme entlastet werden. Aus diesem Grund sind die Verfügbarkeit von HGÜ-Netzen und damit der Umgang mit DC-Fehlern von enormer Bedeutung. Durch die fehlenden natürlichen Nulldurchgänge und großen Anstiege der Fehlerströme ist eine Anwendung bestehender AC-Schutztechniken nicht möglich. Dies erfordert den Entwurf neuartiger HGÜ-Netzschutzkonzepte, die die in Drehstromsystemen etablierten Anforderungen hinsichtlich Schnelligkeit, Zuverlässigkeit, Empfindlichkeit, Selektivität und Wirtschaftlichkeit erfüllen. Der Gegenstand dieser Arbeit ist die Ermittlung von Netzfehlercharakteristiken in ausgedehnten vermaschten HGÜ-Netzen und daraus abgeleitet die Konzeption und Analyse von Fehlerdetektions- und Fehlerklärungsverfahren. Dabei wird der Fokus auf DC-Leitungsfehler gelegt

Muscle Fiber Viability, a Novel Method for the Fast Detection of Ischemic Muscle Injury in Rats

Acute lower extremity ischemia is a limb- and life-threatening clinical problem. Rapid detection of the degree of injury is crucial, however at present there are no exact diagnostic tests available to achieve this purpose. Our goal was to examine a novel technique - which has the potential to accurately assess the degree of ischemic muscle injury within a short period of time - in a clinically relevant rodent model. Male Wistar rats were exposed to 4, 6, 8 and 9 hours of bilateral lower limb ischemia induced by the occlusion of the infrarenal aorta. Additional animals underwent 8 and 9 hours of ischemia followed by 2 hours of reperfusion to examine the effects of revascularization. Muscle samples were collected from the left anterior tibial muscle for viability assessment. The degree of muscle damage (muscle fiber viability) was assessed by morphometric evaluation of NADH-tetrazolium reductase reaction on frozen sections. Right hind limbs were perfusion-fixed with paraformaldehyde and glutaraldehyde for light and electron microscopic examinations. Muscle fiber viability decreased progressively over the time of ischemia, with significant differences found between the consecutive times. High correlation was detected between the length of ischemia and the values of muscle fiber viability. After reperfusion, viability showed significant reduction in the 8-hour-ischemia and 2-hour-reperfusion group compared to the 8-hour-ischemia-only group, and decreased further after 9 hours of ischemia and 2 hours of reperfusion. Light- and electron microscopic findings correlated strongly with the values of muscle fiber viability: lesser viability values represented higher degree of ultrastructural injury while similar viability results corresponded to similar morphological injury. Muscle fiber viability was capable of accurately determining the degree of muscle injury in our rat model. Our method might therefore be useful in clinical settings in the diagnostics of acute ischemic muscle injury

Transformation of Cs-IONSIV® into a ceramic wasteform by hot isostatic pressing

A simple method to directly convert Cs-exchanged IONSIV® IE-911 into a ceramic wasteform by hot isostatic pressing (1100 °C/190 MPa/2 hr) is presented. Two major Cs-containing phases, Cs2TiNb6O18 and Cs2ZrSi6O15, and a series of mixed oxides form. The microstructure and phase assemblage of the samples as a function of Cs content were examined using XRD, XRF, SEM and TEM/EDX. The chemical aqueous durability of the materials was investigated using the MCC-1 and PCT-B standard test methods. For HIPed Cs-IONSIV® samples, the MCC-1 normalised release rates of Cs were <1.57 × 10−1 g m−2 d−1 at 0–28 days, and <3.78 × 10−2 g m−2 d−1 for PCT-B at 7 days. The low rates are indicative of a safe long-term immobilisation matrix for Cs formed directly from spent IONSIV®. It was also demonstrated that the phase formation can be altered by adding Ti metal due to a controlled redox environment