An Investigation of Fuzzy Multiple Heuristic Orderings in the Construction of University Examination Timetables

In this paper, we present an investigation into using fuzzy methodologies to guide the construction of high quality feasible examination timetabling solutions. The provision of automated solutions to the examination timetabling problem is achieved through a combination of construction and improvement. The enhancement of solutions through the use of techniques such as metaheuristics is, in some cases, dependent on the quality of the solution obtained during the construction process. With a few notable exceptions, recent research has concentrated on the improvement of solutions as opposed to focusing on investigating the ‘best’ approaches to the construction phase. Addressing this issue, our approach is based on combining multiple criteria in deciding on how the construction phase should proceed. Fuzzy methods were used to combine three single construction heuristics into three different pair wise combinations of heuristics in order to guide the order in which exams were selected to be inserted into the timetable solution. In order to investigate the approach, we compared the performance of the various heuristic approaches with respect to a number of important criteria (overall cost penalty, number of skipped exams, number of iterations of a rescheduling procedure required and computational time) on twelve well-known benchmark problems. We demonstrate that the fuzzy combination of heuristics allows high quality solutions to be constructed. On one of the twelve problems we obtained lower penalty than any previously published constructive method and for all twelve we obtained lower penalty than when any of the single heuristics were used alone. Furthermore, we demonstrate that the fuzzy approach used less backtracking when constructing solutions than any of the single heuristics. We conclude that this novel fuzzy approach is a highly effective method for heuristically constructing solutions and, as such, has particular relevance to real-world situations in which the construction of feasible solutions is often a difficult task in its own right.

An examination of the rheological and mucoadhesive properties of poly(Acrylic acid) organogels designed as platforms for local drug delivery to the oral cavity

This study examined the rheological/mucoadhesive properties of poly (acrylic acid) PAA organogels as platforms for drug delivery to the oral cavity. Organogels were prepared using PAA (3%, 5%, 10% w/w) dissolved in ethylene glycol (EG), propylene glycol (PG), 1,3-propylene glycol (1,3-PG), 1,5-propanediol (1,5-PD), polyethylene glycol 400 (PEG 400), or glycerol. All organogels exhibited pseudoplastic flow. The increase in storage (G') and loss (G '') moduli of organogels as a function of frequency was minimal, G '' was greater than G '' (at all frequencies), and the loss tangent <1, indicative of gel behavior. Organogels prepared using EG, PG, and 1,3-propanediol (1,3-PD) exhibited similar flow/viscoelastic properties. Enhanced rheological structuring was associated with organogels prepared using glycerol (in particular) and PEG 400 due to their interaction with adjacent carboxylic acid groups on each chain and on adjacent chains. All organogels (with the exception of 1,5-PD) exhibited greater network structure than aqueous PAA gels. Organogel mucoadhesion increased with polymer concentration. Greatest mucoadhesion was associated with glycerol-based formulations, whereas aqueous PAA gels exhibited the lowest mucoadhesion. The enhanced network structure and the excellent mucoadhesive properties of these organogels, both of which may be engineered through choice of polymer concentration/solvent type, may be clinically useful for the delivery of drugs to the oral cavity.

Econometric analysis of microscopic simulation models

Microscopic simulation models are often evaluated based on visual inspection of the results. This paper presents formal econometric techniques to compare microscopic simulation (MS) models with real-life data. A related result is a methodology to compare different MS models with each other. For this purpose, possible parameters of interest, such as mean returns, or autocorrelation patterns, are classified and characterized. For each class of characteristics, the appropriate techniques are presented. We illustrate the methodology by comparing the MS model developed by He and Li [J. Econ. Dynam. Control, 2007, 31, 3396-3426, Quant. Finance, 2008, 8, 59-79] with actual data.

Coercion in the Community: A Situated Approach to the Examination of Ethical Challenges for Mental Health Social Workers

Increasingly, mental health social workers in the United Kingdom and elsewhere in the world are employing coercive interventions with clients. This paper explores this trend in the context of community-based settings, using national and international research literature on this subject. It begins with a discussion about the complex, contested nature of ideas on coercion. The authors then explore debates about how coercion is perceived and applied in practice. They choose two forms of coercion*/informal types of leverage, and the legally mandated use of Community Treatment Orders*/to highlight the range of ethical problems and dilemmas that confront practitioners in this field. The authors conclude by developing a tentative, explanatory model to explain how and why mental health social workers should consider a more holistic, situated approach to help deal with ethical concerns about the use of coercion.