Finding longest increasing and common subsequences in streaming data

We present algorithms and lower bounds for the Longest Increasing Subsequence (LIS) and Longest Common Subsequence (LCS) problems in the data-streaming model. To decide if the LIS of a given stream of elements drawn from an alphabet αbet has length at least k, we discuss a one-pass algorithm using O(k log αbetsize) space, with update time either O(log k) or O(log log αbetsize); for αbetsize = O(1), we can achieve O(log k) space and constant-time updates. We also prove a lower bound of Ω(k) on the space requirement for this problem for general alphabets αbet, even when the input stream is a permutation of αbet. For finding the actual LIS, we give a ⌈log (1 + 1/ɛ)-pass algorithm using O(k^1+ɛlog αbetsize) space, for any ɛ > 0. For LCS, there is a trivial Θ(1)-approximate O(log n)-space streaming algorithm when αbetsize = O(1). For general alphabets αbet, the problem is much harder. We prove several lower bounds on the LCS problem, of which the strongest is the following: it is necessary to use Ω(n/ρ²) space to approximate the LCS of two n-element streams to within a factor of ρ, even if the streams are permutations of each other. A preliminary version of this paper appears in the Proceedings of the 11th International Computing and Combinatorics Conference (COCOON'05), August 2005, pp. 263–272.     

Hugo Münsterberg and the Origins of Vocational Guidance

Hugo Münsterberg was among the most famous psychologists in the world at the turn of the 20th century. Despite his preeminence and associations with prominent leaders in several disciples, including Frank Parsons, his abrasive personality and unpopular politics led to his work being largely ignored during the 20th century. One such work is H. Münsterberg's (1910c) Vocation and Learning: A Popular Reading Course, which represents an early trait‐and‐factor psychological model of vocation. This triangular model suggests that people and vocations are composed of thinking, feeling, and willing dimensions that must be aligned to find the most suitable vocation for the person.     

Sequential sharing rules for river sharing problems

We analyse the redistribution of a resource amongst agents who have claims to the resource and who are ordered linearly. A well known example of this particular situation is the river sharing problem. We exploit the linear order of agents to transform the river sharing problem to a sequence of two-agent river sharing problems. These reduced problems are mathematically equivalent to bankruptcy problems and can therefore be solved using any bankruptcy rule. Our proposed class of solutions, that we call sequential sharing rules, solves the river sharing problem. Our approach extends the bankruptcy literature to settings with a sequential structure of both the agents and the resource to be shared. In the paper, we first characterise the class of sequential sharing rules. Subsequently, we apply sequential sharing rules based on four classical bankruptcy rules, assess their properties, provide two characterisations of one specific rule, and compare sequential sharing rules with three alternative solutions to the river sharing problem.     

Empowering the activist: Using framing devices on activist organizations’ web sites

The researchers analyzed activist organization web sites to determine the framing techniques employed in their public relations messages. The macro framework for this study was based on the work of sociologists David Snow and Robert Benford, who focus on how social activist organizations frame their messages. At the micro level, the researchers examined the web sites for the presence or absence of five devices identified by Gamson and Modigliani (American Journal of Sociology 1989;95:1–37) as commonly used when framing issues.     

The relationship between perceived employability and subsequent health

Being capable of getting new employment may enable an employee to cope with turbulent situations or deteriorating job conditions. Individuals who have higher perceived employability are likely to appraise a situation at work more favourably, and consequently experience better health and well-being. The aim of the present study was to investigate the relationship between perceived employability and subsequent health, while controlling for baseline health, background factors, and work environment exposures. The study is based on 53 items in the National Working Life Cohort in Sweden from two data collections (2004 and 2005), comprising 1918 individuals. Forced entry hierarchical regression analysis showed that, after controlling for demographics, psychological demands, control, and ergonomic exposures, perceived employability was positively associated with global health and mental well-being, but unrelated to physical complaints. When baseline health status was added, perceived employability was still a significant predictor of two out of three outcome variables. Individuals with higher perceived employability had a tendency to report better health and well-being a year later. It is concluded that how an employee perceives his or her possibilities in regard to acquiring new employment is relevant for well-being at a later stage. Perceived employability, which has been little studied before, is therefore a useful concept in health promotion, both at the individual and at the organizational level.     

Portfolio decision-making genres: A case study

This article addresses the portfolio management practices and challenges of contemporary firms. Based on a review of the extant literature on project selection, termination and deletion decisions, we conducted an in-depth interview study with 19 key informants in 11 multinational firms. We identified three genres of portfolio management decision making: formalist-reactive, intuitive, and integrative. Each genre can be described by a unique set of portfolio management practices. For example, formalist-reactive firms rely on quantitative criteria while intuitive firms prefer qualitative criteria. In addition, each genre has to overcome a unique set of challenges. We discuss the three genres in detail and provide several implications for portfolio management decision making.     

The Sample Selection Model from a Method of Moments Perspective

It is shown how the usual two-step estimator for the standard sample selection model can be seen as a method of moments estimator. Standard GMM theory can be brought to bear on this model, greatly simplifying the derivation of the asymptotic properties of this model. Using this setup, the asymptotic variance is derived in detail and a consistent estimator of it is obtained that is guaranteed to be positive definite, in contrast with the estimator given in the literature. It is demonstrated how the MM approach easily accommodates variations on the estimator, like the two-step IV estimator that handles endogenous regressors, and a two-step GLS estimator. Furthermore, it is shown that from the MM formulation, it is straightforward to derive various specification tests, in particular tests for selection bias, equivalence with the censored regression model, normality, homoskedasticity, and exogeneity.     

“Nothing goes as planned”: Practitioners reflect on matching children and foster families

Matching children with foster carers is an important step in every nonkinship family foster care placement. Although guidelines for matching are provided in several studies, the case‐specific context of the decision can influence the practitioners' ability to adhere to these guidelines. Therefore, this study answers the following question: “How does the case‐specific context influence the practitioners' decision‐making process regarding matching in family foster care?” Using a qualitative design, 20 semistructured interviews were conducted with practitioners matching children with foster families. Three themes emerged representing different layers of practitioners' everyday decision‐making: matching as planned, matching being tailored, and matching being compromised. The results show that exceptions are part of practitioners' daily work, either due to the belief that it might benefit those involved or because of obstacles presented during the decision‐making process. When the decision is compromised, matching practitioners lower their standards, while at the same time safeguarding the quality of the match. This proves that matching in practice is more than choosing a family, and guidelines are needed to determine what “good‐enough” matching should entail.     

Integration of immigrants: the role of language proficiency and experience

In this article, the authors evaluate a Swedish pilot scheme that targeted immigrants with weak Swedish-language skills registered as unemployed at public employment offices. By sandwiching work-oriented language teaching and practical workplace training, the project aimed at enhancing the employability of project participants but also at alerting them to and preparing them for available training and further education opportunities. For the evaluation, a comparison group of nonparticipants was selected using a propensity score methodology. The results show that participation in the pilot scheme project resulted in much speedier transfers from open unemployment to employment, training, and education.     

Regulations, policies and practices concerning work stress in five European countries

A comparative inventory of regulations, policies and practices in The Netherlands, Sweden, UK, Germany and France with regard to the prevention of work stress was carried out. In each country data were collected by means of interviews with key informants and through exploring relevant documents and literature. It was found that Sweden, The Netherlands and the UK—those countries with framework legislation in the field of health and safety—recognize stress as an important health and safety topic, whereas Germany and France do not yet recognize stress as an important policy issue. However, even in the first group of countries less attention is being paid towards psychosocial work characteristics when compared with traditional health and safety issues, such as noise, machine safety and toxic agents. There is a clear lack of well-documented (national) 'examples of good preventive practice', even in Sweden and The Netherlands. Recommendations are being formulated concerning type of legislation, guidance and information, monitoring and risk assessment, costs and benefits, examples of good practice and European networking.