A hybrid genetic algorithm for the batch sequencing problem on identical parallel machines

The batch sequencing problem (BSP) has been the focus of much research thanks to its practical applicability and NP-hard nature. This study aims to solve an extension of the problem from single machine case to parallel machine case. A dispatching rule called the EDD (Earliest Due Date)-Greedy heuristic and a pure genetic algorithm (GA) are proposed, and then combine them through an insertion method called the Gene Bank Strategy. Several test cases of up to 12 machines and 60 jobs are randomly generated and solved. Those experiments show that the introduced hybrid GA can provide far better results than its two component algorithms that can also independently solve the problem.     

Children's Vocational Development: A Research Rationale

Vocational development research and interventions have focused primarily on adolescents and young adults. The lack of attention to career development antecedents in children has led to a serious neglect of this period of life when the foundation is laid for career choices and outcomes in later life. A harmful by‐product is the frequent preclusion of gender‐atypical occupational pathways by boys and especially by girls. To address this situation, the authors recommend identifying a core set of constructs that describe children's vocational development and developing sound instruments to measure them, leading to a longitudinal study ranging from childhood to early adulthood.     

Approximability of the subset sum reconfiguration problem

The subset sum problem is a well-known NP-complete problem in which we wish to find a packing (subset) of items (integers) into a knapsack with capacity so that the sum of the integers in the packing is at most the capacity of the knapsack and at least a given integer threshold. In this paper, we study the problem of reconfiguring one packing into another packing by moving only one item at a time, while at all times maintaining the feasibility of packings. First we show that this decision problem is strongly NP-hard, and is PSPACE-complete if we are given a conflict graph for the set of items in which each vertex corresponds to an item and each edge represents a pair of items that are not allowed to be packed together into the knapsack. We then study an optimization version of the problem: we wish to maximize the minimum sum among all packings in a reconfiguration. We show that this maximization problem admits a polynomial-time approximation scheme, while the problem is APX-hard if we are given a conflict graph.     

Unrepresentative Information: The Case of Newspaper Reporting on Campaign Finance

This article examines evidence of sampling or statistical biasin newspaper reporting on campaign finance. We compile all storiesfrom the five largest circulation newspapers in the United Statesthat mention a dollar amount for campaign expenditures, contributions,or receipts from 1996 to 2000. We compare these figures to thoserecorded by the Federal Election Commission (FEC). The averagefigures reported in newspapers exceed the figures from the FECby as much as eightfold. Press reports also focus excessivelyon corporate contributions and soft money, rather than on themore common types of donors—individual—and typesof contributions—hard money. We further find that thesebiases are reflected in public perceptions of money in elections.Survey respondents overstate the amount of money raised andthe share from different groups by roughly the amount foundin newspapers, and better-educated people (those most likelyto read newspapers) showed the greatest discrepancy betweentheir beliefs and the facts.     

Career Adaptability in Childhood

Childhood marks the dawn of vocational development, involving developmental tasks, transitions, and change. Children must acquire the rudiments of career adaptability to envision a future, make educational and vocational decisions, explore self and occupations, and problem solve. The authors situate child vocational development within human life span and life course development paradigms and career development theory. They then consider the theoretical origins of career adaptability and examine it as a critical construct for construing vocational development. Two models derived from career construction theory offer guides for research and counseling practice designed to foster development through work and other social roles.     

Ill health and social conditions amongst migrants and refugees—the case of Sweden

The present article delineates the state of health and socioeconomic situation of migrants and refugees in Sweden. Special attention is given to refugees. Migrants appear to have more extensive health problems and a shorter longevity span than native Swedes. The refugees constitute an especially exposed group of migrants. Experiences in the home country that relate to organised violence is a specific problem for this group. It has been estimated that 20 to 25 per cent of all adult refugees who have arrived to Sweden during the recent years have experienced torture in their native countries. Swedish migrant and refugee policy operates according to a model of decentralisation, aiming to avoid ethnic segregation in the big city areas. However, the integration policy seems, in many instances, to have had a negative affect on the situation of the refugees. During the period of time, in which the refugees wait for a residence permit, they are not permitted to work. The long period of forced inactivity—in some instances up to a couple of years—seems frequently to have aggravated the health of the refugees. In addition it appears to contribute to the ever increasing animosity towards them.     

Static versus dynamic analysis of the interaction between female labour-force participation and fertility

Numerous studies have found a negative relationship between female labour-force participation and fertility. In theory, there could be three explanations of this finding: (i) causality runs from labour-force participation to fertility, (ii) causality runs from fertility to labour-force participation, (iii) causality runs both ways. Alternatively, the relationship may not be a causal one. In practice, empirical studies covering a wide range of Western countries at different times, and utilizing a great variety of methods and techniques, have shown all four possibilities to be plausible. This may be because outcomes differ from country to country for socio-cultural reasons, or from period to period for historical ones. If so, applying various methodologies to data for one country at a particular point in time should yield consistent results that all point in one direction only. If they did not outcomes would appear to be method-dependent. The single data set used in this study refers to the Netherlands in 1984 (ORIN project). The relationship between fertility and labour-force participation in this data set is investigated by means of three methodologies, ranging from ‘static’ to ‘dynamic’, i.e., differing according to the degree in which they take the temporal aspects of the decision-making process underlying this relationship into account: simultaneous logit analysis, Granger analysis and Markov analysis. Each main approach is applied in two different ways or on two different subgroups, for a total of six applications. In spite of diverging operationalizations of the basic variables, it turns out that four of these six analyses favour the inference that fertility decisions do have an impact on labour force participation decisions but not the other way around, whereas the other two confirm earlier findings (from data sets collected during the 1970s) that the relationship is reciprocal. Substantively, this might indicate that the pattern of covariance is changing. But ‘static’ simultaneous logit analysis is the only method to consistently point at this causal unidirectionality, while outcomes from Granger and Markov analysis depend on the modality applied. Methodologically, this means that the issue of method-dependency, at least in this area, remains largely unresolved.     

Importance of active listening in treating workers with musculoskeletal disorders

Female assembly workers reporting constant neck and shoulder pain, despite ergonomically acceptable working conditions, were interviewed. As a starting point in the interviews, the patients were asked to describe their general situation at work. Their reports were fed back and discussed with company management in a wider group meeting and resulted in an improvement in their attitudes to those workers. A climate of confidence and well-being was created, which the women experienced as genuine. The workers' report of pains improved dramatically and absence due to musculoskeletal disorders was reduced by more than 90% during the following year.