Flow shop batching and scheduling with sequence-dependent setup times

This paper addresses the flow shop batching and scheduling problem where sequence-dependent family setup times are present and the objective is to minimize makespan. We consider violating the group technology assumption by dividing product families into batches. In order to reduce setup times, inconsistent batches are formed on different machines, which lead to non-permutation schedules. To the best of our knowledge, this is the first time that the splitting of job families into inconsistent batches has been considered in a flow shop system. A tabu search algorithm is developed which contains several neighbourhood functions, double tabu lists and a multilevel diversification structure. Compared to the state-of-the-art meta-heuristics for this problem, the proposed tabu search algorithm achieves further improvement when the group scheduling assumption is dropped. Also, various experiments conducted on the benchmark problem instances confirm the benefits of batching. Therefore, it will be prudent for the practitioners to consider adopting inconsistent batches and non-permutation schedules to improve their operational efficiency within a reasonable amount of computational effort.     

Optimal allocation of change points in simple step-stress experiments under Type-II censoring

In simple step-stress experiments under Type-II censoring with the cumulative exposure model and exponentially distributed lifetimes, maximum likelihood estimates (MLE) of the expected lifetimes may not exist due to the absence of failure times either before or after the stress change point. For this reason, when planning a step-stress experiment, the change point could be chosen so as to minimize the probability of non-existence of the MLE. These non-existence probabilities are examined and compared in the one- as well as the two-sample situations. Moreover, the optimal allocations of the change points are discussed and the effects of the use of non-optimal choices for the change points are assessed.     

Vorwort der Herausgeber

Ohne Zusammenfassung     

Die Restspannungen in der Umgebung der kaltverfestigten Bohrung

Zusammenfassung Gegenstand der Untersuchung ist die Spannungsverteilung in der unendlichen elastisch-plastischen Scheibe, die durch die Druckbelastung einer kreisf?rmigen Bohrung hervorgerufen wird. Der Rechnung liegt die Trescasche Flie?bedingung, die zugeordnete Flie?regel sowie lineare isotrope Verfestigung zugrunde. Bestimmt werden ferner die Restspannungen und die Aufweitung der Bohrung.     

Making understanders out of parsers: Semantically driven parsing as a key concept for realistic text understanding applications

Semantically driven natural language parsers have found wide-spread application as a text processing methodology for knowledge-based information retrieval systems. It is argued that this parsing technique particularly corresponds to the requirements inherent to large-scale text analysis. Unfortunately, this approach suffers from several shortcomings which demand a thorough reformulation of its paradigm. Incorporating principles from conceptual analysis and word expert parsing in a model of lexically distributed text parsing, the focus of the modifications proposed in this article, is on a clean declarative separation of linguistio and other knowledge representation levels, abstraction mechanisms leading to a small collection of specification primitives for the parser, and an attempt to incorporate linguistic generalizations and modularization principles into the design of a semantic text grammar. A sample parse illustrates the operation and linguistic coverage of a lexically distributed text parser based on these theoretical considerations with respect to the semantic analysis of noun groups, simple assertional sentences, nominal anaphora, and textual ellipsis.     

Herstellung,Verarbeitung und Eigenschaften höherfester Stähle für den Einsatz in Windenergieanlagen

Production, processing and properties of higher‐strength steel plates for application in wind energy plants. The mechanical and technological demands on steels for offshore wind energy plants are high. Advanced technologies in steel production make normalized or thermomechanically rolled plates with minimum yield strengths up to 460 MPa as well as quenched and tempered steels with minimum yield strengths from 520 up to 1100 MPa available for construction. Plates with up to 460 MPa are well established for building wind energy plants. Material properties and processing of these steel grades are well known. High‐strength steels offer further possibilities for construction. These steels are characterised by high yield strength and at the same time high toughness and excellent processing behaviour. By modern fracture mechanical safety concepts, it could be shown, that even under critical service conditions there can be guaranteed a high level of safety against brittle failure.     

In Situ Mine Water Treatment: Field Experiment at the Flooded Königstein Uranium Mine (Germany)

Within the WISMUT environmental remediation programme, the rehabilitation of the former uranium mine at Königstein is a very special case due to its use of underground leaching and its location near the Elbe River. The mine water is acidic, oxidizing, and polluted with uranium and other contaminants, and must be pumped to the surface and treated. In-situ water treatment approaches have been investigated to optimise further flooding and shorten the period of conventional water treatment. In 2010/2011, a field-scale experiment was carried out: about 120 t of alkalinity were successfully injected into the partially flooded mine. Tracer signals and geochemical reactions achieved general expectations. Based on the results, a site-specific technology concept was developed to flood the mine to its natural decant level.