Operator performance and subjective response in control of flexible manufacturing systems

In this study, allocation of functions and system size (number of machines) were manipulated to test their effects on operator performance and subjective response in a flexible manufacturing system (FMS). An experiment was conducted using a cross-over design with three independent variables: number of machines, task allocation, and sequence of task presentation. Operator performance was measured by response time, and subjective response assessed using two questionnaires. Physiological measures were also taken (EKG and respiratory rate). The results revealed that the number of machines in the system did not affect performance or subjective or physiological response while the effect of allocation level was significant for both performance and subjective response.     

Random Pooling Designs Under Various Structures

Balding et al. (1995) showed that randomizing over the k-set space yields much better pooling designs than the random pooling design without the k-restriction. A natural question arises as to whether a smaller subspace, i.e., a space with more structure, will yield even better results. We take the random subset containment design recently proposed by Macula, which randomizes over a subspace of the k-set space, as our guinea pig to compare with the k-set space. Unfortunately the performance of the subset containment design is hard to analyze and only approximations are given. For a set of parameters, we are able to produce either an exact analysis or very good approximations. The comparisons under these parameters seem to favor the k-set space.     

A fuzzy set approach for R&D portfolio selection using a real options valuation model

Making R&D portfolio decision is difficult, because long lead times of R&D and market and technology dynamics lead to unavailable and unreliable collected data for portfolio management. The objective of this research is to develop a fuzzy R&D portfolio selection model to hedge against the R&D uncertainty. Fuzzy set theory is applied to model uncertain and flexible project information. Since traditional project valuation methods often underestimate the risky project, a fuzzy compound-options model is used to evaluate the value of each R&D project. The R&D portfolio selection problem is formulated as a fuzzy zero–one integer programming model that can handle both uncertain and flexible parameters to determine the optimal project portfolio. A new transformation method based on qualitative possibility theory is developed to convert the fuzzy portfolio selection model into a crisp mathematical model from the risk-averse perspective. The transformed model can be solved by an optimization technique. An example is used to illustrate the proposed approach. We conclude that the proposed approach can assist decision makers in selecting suitable R&D portfolios, while there is a lack of reliable project information.     

Constraints to the fulfillment of residential preferences among Texas homebuyers

A 1983 survey of Texas homebuyers reveals a high degree of mismatch between their preferred and actual residences. Analysis indicates that the logit of fulfilling residential preference is largely determined by the type of area preferred and the occupation and age of the homebuyer. Mismatch is most common among homebuyers preferring a suburban location, less so for those preferring nonmetropolitan residences, and lowest among people preferring central cities. Occupation as a social structural variable also affects homebuyers ’ chance of fulfilling residential preference. Professionals are more likely to fulfill their residential preferences than persons in other occupations. Finally, younger persons suffer a higher degree of residential mismatch than older persons.     

Unmet Expectations and Symptoms of Depression among the Three Gorges Project Resettlers

To successfully resettle 1.27 million Chinese for the construction of the Three Gorges Project (TGP), the Chinese government employed a new re-resettlement policy which emphasizes infrastructural development of the resettlement sites to assure resettlers a sustainable livelihood following resettlement. Unfortunately, many benefits the policy promised have not materialized. As a result, many resettlers have suffered an increase in depressive symptoms associated with unmet expectations. Using panel data collected before and after relocation from a sample of Three Gorges resettlers, we found that a high proportion of resettlers reported unmet expectations which were significantly associated with an increase in depressive symptoms. Our findings indicate that undeliverable promises can backfire and further aggravate the harm inflicted on the displaced caused by the project-induced displacement. From the perspective of resettlers, a sound coping strategy to minimize the harm caused by the displacement on their mental wellbeing is to expect for the worst.     

What difference do different settings in residential care make for young people? A comparison of family‐style homes and institutions in Sweden

Residential care in Sweden has undergone great change in recent decades. With new small family-style institutions, the boundaries between residential care and foster care have been blurred. Almost all residential care used to be run by the public sector. Today about 80 per cent is privately run. This study compares three different settings in residential care: institutions run by the public sector, privately run institutions and family-style homes. Among other things, it is found that the institutions run by the public sector have better educated staff and a higher staff–resident ratio than privately run institutions. Despite this, they are more restrictive in their intake and they have youths with fewer problems, especially delinquency and other antisocial behaviour. The results are discussed in relation to developments in the residential care sector in Sweden and in relation to the balance between care and treatment.     

‘If I were given the chance’: understanding the use of leisure time by adults with learning disabilities

Despite UK government policy emphasising the rights and choices of people with learning disabilities, opportunities to choose fulfilling leisure activities remain severely constrained. Following a brief literature review we present a co-inquiry study developing a deeper understanding of the persistent space between actual and desired use of leisure time. We explore the potential of the capability approach to aid understanding of learning disabled people’s constrained choices of leisure activities, and constrained roles as researchers, as matters of human rights and social justice.     

How to Approximate a Histogram by a Normal Density

Which normal density curve best approximates the sample histogram? The answer suggested here is the normal curve that minimizes the integrated squared deviation between the histogram and the normal curve. A simple computational procedure is described to produce this best-fitting normal density. A few examples are presented to illustrate that this normal curve does indeed provide a visually satisfying fit, one that is better than the traditional , s answer. Some further aspects of this procedure are investigated. In particular it is shown that there is a satisfactory answer that is independent of the bar width of the histogram. It is also noted that this graphical procedure provides highly robust estimates of the sample mean and standard deviation. We demonstrate our technique by using data including Newcomb's data of passage time of light and Fisher's iris data.