Engineered versus standard evolutionary algorithms: A case study in batch scheduling with recourse

An engineered evolutionary algorithm for a realistic chemical batch scheduling problem with uncertain data is developed systematically. The problem is formulated as a two stage stochastic integer program with discrete scenarios. The model is solved by a stage decomposition-based hybrid algorithm using an evolutionary algorithm combined with mixed-integer programming. Earlier experiments with a standard evolutionary algorithm led to the hypothesis that the constrained search space is not covered well such that in some cases the population converges to a subset of the solution space which does not include the best known solution. An efficient engineered evolutionary algorithm is developed which is shown to cover the feasible set significantly better such that a high quality feasible schedule can be generated comparatively fast. As the hierarchical structure of the case study is typical for many batch scheduling problems, some general principles may be postulated from the experience gained here.     

Managing standards compliance

Software engineering standards determine practices that “compliant” software processes shall follow. Standards generally define practices in terms of constraints that must hold for documents. The document types identified by standards include typical development products, such as user requirements, and also process-oriented documents, such as progress reviews and management reports. The degree of standards compliance can be established by checking these documents against the constraints. It is neither practical nor desirable to enforce compliance at all points in the development process. Thus, compliance must be managed rather than imposed. We outline a model of standards and compliance and illustrate it with some examples. We give a brief account of the notations and method we have developed to support the use of the model and describe a support environment we have constructed. The principal contributions of our work are: the identification of the issue of standards compliance; the development of a model of standards and support for compliance management; the development of a formal model of product state with associated notation; a powerful policy scheme that triggers checks; and a flexible and scalable compliance management view     

Phase-Field Modeling of Eutectic Growth in a Ti-Fe System with Multiple Nuclei and Misorientations

In this article a phase-field model to investigate the formation of eutectic structures in a Ti-Fe alloy with high elastic misfit is introduced. Based on linear microelasticity theory, an elastic model is designed to incorporate the elastic energy into the phase-field formalism and later on adopted to growth of multiple nuclei with arbitrary orientations by including the orientation energy in phase-field ansatz. By using this model, we investigate the free growth of a limited number of eutectic nuclei and examine the influence of orientation free energies on elastic fields and the resulting microstructure.     

A reference model of virtual service production networks

Virtual organisation of collaborative networks frequently demands for information and communication technology to support coordination of cross-organisational business process chains. Service-oriented software technologies provide promising means to regulate and enforce coordination of cross-organisational software service interactions but miss organisational abstractions and methodology. This paper proposes a conceptual reference model of collaborative network coordination that satisfies flexibility and agility requirements of virtual organisation by building on common software service abstractions and lifecycle methodology. In particular, the model focuses collaborative service networks and introduces the concept of virtual business service that represents business service processes as software service abstractions and supports flexible regulation and agile enforcement of their coordination by means of software service lifecycle methodology. For demonstration and evaluation purpose, we present a case study of service-oriented systems analysis for virtual organisation of a collaborative e-science network that adopts our conceptual reference model.     

CARISMA: context-aware reflective middleware system for mobile applications

Mobile devices, such as mobile phones and personal digital assistants, have gained wide-spread popularity. These devices will increasingly be networked, thus enabling the construction of distributed applications that have to adapt to changes in context, such as variations in network bandwidth, battery power, connectivity, reachability of services and hosts, etc. In this paper, we describe CARISMA, a mobile computing middleware which exploits the principle of reflection to enhance the construction of adaptive and context-aware mobile applications. The middleware provides software engineers with primitives to describe how context changes should be handled using policies. These policies may conflict. We classify the different types of conflicts that may arise in mobile computing and argue that conflicts cannot be resolved statically at the time applications are designed, but, rather, need to be resolved at execution time. We demonstrate a method by which policy conflicts can be handled; this method uses a microeconomic approach that relies on a particular type of sealed-bid auction. We describe how this method is implemented in the CARISMA middleware architecture and sketch a distributed context-aware application for mobile devices to illustrate how the method works in practice. We show, by way of a systematic performance evaluation, that conflict resolution does not imply undue overheads, before comparing our research to related work and concluding the paper.     

Citrate Starch — Application as Resistant Starch in Different Food Systems

Chemically modified starch was used as resistant starch (RS) to enhance the dietary fibre content in foods. Citrate starch was produced by esterification of starches of various origins and added to toast bread, wafers, pasta and extruded products. The RS content as well as relevant product features were determined and results compared to those of products without any citrate starch addition. The results show that the RS content in toast bread could be increased by approximately 3%, when 7.5% citrate starch was added, compared to non-fortified bread. Changes in product features due to addition of citrate starch could be compensated for by variation in the recipe, such as increasing the amount of water. Thus, appealing products could be obtained with an enriched dietary fibre content. The extend of the RS enhancement depends highly on the food system chosen.     

Urinary excretion of proteolyzed alpha1-antitrypsin: specificity, quantitation, and relation to therapy response in patients with acute myeloid leukemia

The purpose of this study was to characterize the long-term safety and efficacy of the stainless-steel Greenfield filter. All patients who underwent Greenfield filter placement at three institutions during tenure of the senior author (L.J.G.) were entered prospectively into a filter registry and followed on an annual basis. Follow-up consisted of clinical examination to evaluate the status of venous disease or recurrence of pulmonary embolism, abdominal radiographs to determine the stability of the filter and an evaluation of the patency of the inferior vena cava and lower extremities. This report summarizes the 20-year experience. The rate of recurrent pulmonary embolism was 4% and the caval patency rate was 96%. Some filter movement of no clinical significance was seen in 8% of cases. There was no procedural mortality and morbidity was minimal. Greenfield filter insertion provides long-term protection from pulmonary embolism while preserving caval patency.