Algorithmic Proof Methods and Cut Elimination for Implicational Logics Part I: Modal Implication

In this work we develop goal-directed deduction methods for the implicational fragment of several modal logics. We give sound and complete procedures for strict implication of K, T, K4, S4, K5, K45, KB, KTB, S5, G and for some intuitionistic variants. In order to achieve a uniform and concise presentation, we first develop our methods in the framework of Labelled Deductive Systems [Gabbay 96]. The proof systems we present are strongly analytical and satisfy a basic property of cut admissibility. We then show that for most of the systems under consideration the labelling mechanism can be avoided by choosing an appropriate way of structuring theories. One peculiar feature of our proof systems is the use of restart rules which allow to re-ask the original goal of a deduction. In case of K, K4, S4 and G, we can eliminate such a rule, without loosing completeness. In all the other cases, by dropping such a rule, we get an intuitionistic variant of each system. The present results are part of a larger project of a goal directed proof theory for non-classical logics; the purpose of this project is to show that most implicational logics stem from slight variations of a unique deduction method, and from different ways of structuring theories. Moreover, the proof systems we present follow the logic programming style of deduction and seem promising for proof search [Gabbay and Reyle 84, Miller et al. 91].     

Process, Content, and Feminist Reflexivity: One Researcher's Exploration

This article explores the unraveling of the relationship between research methodology, process, and content as revealed through my own feminist research project. I examine the evolution of my research process with one participant from a larger study, as I sought to better understand a story she told about racism. First, I address the theoretical underpinnings of feminist reflexivity and research, which challenge traditional paradigms. Next, I present the participant's (a white family day care provider's) story about racism in her practice which was revealed during an interview process. Subsequently, I present a second dialogue around the story in which we (researcher and participant) later engaged. In the process, I analyze my struggles, as a researcher trained in positivist methods, to engage in reflexive research methods. Finally, I evaluate the gains made for me as a researcher in the process and content of research conducted with a feminist reflexive frame and suggest their utility in deconstructing White racism.     

A test for conditional independence between response time and accuracy

An important distinction between different models for response time and accuracy is whether conditional independence (CI) between response time and accuracy is assumed. In the present study, a test for CI given an exponential family model for accuracy (for example, the Rasch model or the one‐parameter logistic model) is proposed and evaluated in a simulation study. The procedure is based on the non‐parametric Kolmogorov–Smirnov tests. As an illustrative example, the CI test was applied to data from an arithmetics test for secondary education.     

Detection of differential item functioning in Rasch models by boosting techniques

Methods for the identification of differential item functioning (DIF) in Rasch models are typically restricted to the case of two subgroups. A boosting algorithm is proposed that is able to handle the more general setting where DIF can be induced by several covariates at the same time. The covariates can be both continuous and (multi‐)categorical, and interactions between covariates can also be considered. The method works for a general parametric model for DIF in Rasch models. Since the boosting algorithm selects variables automatically, it is able to detect the items which induce DIF. It is demonstrated that boosting competes well with traditional methods in the case of subgroups. The method is illustrated by an extensive simulation study and an application to real data.     

Moving in Parallel Toward a Modern Modeling Epistemology: Bayes Factors and Frequentist Modeling Methods

The Bayesian-frequentist debate typically portrays these statistical perspectives as opposing views. However, both Bayesian and frequentist statisticians have expanded their epistemological basis away from a singular focus on the null hypothesis, to a broader perspective involving the development and comparison of competing statistical/mathematical models. For frequentists, statistical developments such as structural equation modeling and multilevel modeling have facilitated this transition. For Bayesians, the Bayes factor has facilitated this transition. The Bayes factor is treated in articles within this issue of Multivariate Behavioral Research. The current presentation provides brief commentary on those articles and more extended discussion of the transition toward a modern modeling epistemology. In certain respects, Bayesians and frequentists share common goals.     

Bayesian Factor Analysis as a Variable-Selection Problem: Alternative Priors and Consequences

Factor analysis is a popular statistical technique for multivariate data analysis. Developments in the structural equation modeling framework have enabled the use of hybrid confirmatory/exploratory approaches in which factor-loading structures can be explored relatively flexibly within a confirmatory factor analysis (CFA) framework. Recently, Muthén & Asparouhov proposed a Bayesian structural equation modeling (BSEM) approach to explore the presence of cross loadings in CFA models. We show that the issue of determining factor-loading patterns may be formulated as a Bayesian variable selection problem in which Muthén and Asparouhov's approach can be regarded as a BSEM approach with ridge regression prior (BSEM-RP). We propose another Bayesian approach, denoted herein as the Bayesian structural equation modeling with spike-and-slab prior (BSEM-SSP), which serves as a one-stage alternative to the BSEM-RP. We review the theoretical advantages and disadvantages of both approaches and compare their empirical performance relative to two modification indices-based approaches and exploratory factor analysis with target rotation. A teacher stress scale data set is used to demonstrate our approach.     

Shoppers in the Spiritual Supermarket: A Quantitative Study of Visitors to Scandinavia’s Largest Alternative Fair

Presenting data from a quantitative survey (N=362) at ‘The Great Alternative Fair’ in Lillestrøm, Norway, this article explores the demographic and religious profiles of the ‘customers’ in the ‘spiritual marketplace’. Many adhere to ideas that are historically associated with different religious traditions. At the same time, there are strong positive statistical correlations between belief in alternative ideas, such as healing, reincarnation, channelling, and clairvoyance. This indicates that such ideas constitute a clustered and shared set of beliefs. Against this background, the article questions the widely held assumption that people who are oriented towards alternative spiritualities are independent of institutions and authorities and it argues that they are informed to a large extent by a set of collective resources. It is suggested that the marketplace, which constitutes a common framework of interaction, plays a key role in connecting various ideas and actors and in creating a common ideological profile.     

Too individualistic for safety culture? Non-traffic related work safety among heavy goods vehicle drivers

IntroductionThis article reports on a study of non-traffic related work safety among drivers of heavy goods vehicles in Denmark. In the heavy goods vehicle transport (HGV) sector only 6.4% of workplace accidents involving drivers are traffic related. HGV work is characterised by solitary work, as drivers tend to work at a physical distance from their own company and their working environment is also influenced by the working environment of other companies e.g. the places where they deliver goods. This study focuses on an analysis of HGV drivers’ and managers’ differentiated understandings of risk and safety and its management within an organisational context. The situational focus involves viewing HGV drivers’ working environment as a part of the organisational structure as well as of other social relationships. An understanding of safety culture as practice is applied with the view of identifying values and attitudes as well as organisational and technical aspects in relation to how individualist or collectivist understandings of risk and safety influence the working environment in HGVs.MethodThe study applied a mixed methods approach and in this article the qualitative interviews conducted with drivers and managers is the primary data source.ResultsThis study suggests a widespread understanding of drivers as being individually oriented in their work, from drivers and management alike. However, the study also demonstrates that, in conducting their work, the drivers are actually interdependent, and share knowledge frequently, albeit informally. The organisational structure of the company shapes their individual attitudes towards safety but they also report being dependent on relationships with, and information from, their fellow colleagues, former colleagues and friends who shape their understandings and attitudes towards hazards and safety practices. The analysis points to risk-taking and unsafe practices as prevalent among HGV drivers, who often refer to risk as trivial and the management of such risks as one’s own responsibility. Knowledge of how to manage risks in everyday practice is shown to be principally related to personal experiences but also to the good advice and examples of fellow drivers.ConclusionsThe analysis points to interdependent and collectivist practices among HGV drivers even though they are perceived as being individualistically oriented when it comes to safety. Therefore, non-traffic related safety practices, in this case the loading and unloading of vehicles, occur in the grey zone of organisational safety management. Despite the fact that organisational safety initiatives are initiated, the management sees limited possibilities for enforcing them and hence safety practice is often left to the individual driver.Practical applicationsA safety culture perspective might enhance work safety among HGV drivers if we are able to understand workplace culture in a pluralistic way. Collectivist practice among the drivers can be utilised in order to improve knowledge sharing and situational safety practices. The informal communication identified among the drivers might offer a new model for safety initiatives based on more collectivist, albeit informal, safety culture practices on behalf of HGV companies.     

Health behaviour change theory meets falls prevention: Feasibility of a habit-based balance and strength exercise intervention for older adults

ObjectivesHabit formation is a proposed mechanism for behaviour maintenance. Very few falls prevention studies have adopted this as an intervention framework and outcome. Therefore, we tested feasibility of a theory-based behaviour change intervention that encouraged women to embed balance and strength exercises into daily life routines (e.g., eating, self-care routines).DesignThe EASY LiFE study was a mixed-methods, 4-month feasibility intervention that included seven group-based sessions and two telephone calls.Main outcome measuresWe obtained performance-based (i.e., Short-Physical-Performance-Battery) and psychological self-report measures (i.e., intention, self-efficacy, planning, action control, habit strength, quality of life) from 13 women at baseline (T1) and 4-month follow-up (T2). We applied the Framework-Method to post-intervention, semi-structured interviews to evaluate program content and delivery.ResultsIn total, 10 of 13 women completed the program (M_age = 66.23, SD = 3.98) and showed changes in their level of action control [mean difference_T1−T2 = 1.7, 95% CI (−2.2 to −0.8)], action planning [mean difference_T1−T2 = 0.8, 95% CI (−1.1 to −0.2)], automaticity [mean difference_T1−T2 = 2.5, 95% CI (−3.7 to −1.2)], and exercise identity [mean difference_T1−T2 = 2.0, 95% CI (−3.2 to −0.8)]. Based on the Theoretical Domains Framework we identified knowledge, behavioural regulation, and social factors as important themes. For program delivery, dominant themes were engagement, session facilitators and group format.ConclusionThe theory-based framework showed feasibility for promoting lifestyle integrated balance and strength exercise habits. Using activity and object-based cues may be particularly effective in generating action and automaticity.     

KAGAWA TOYOHIKO (1888–1960): WITNESS TO THE COSMIC DRAMA

At home and abroad, Kagawa Toyohiko was probably the best‐known Japanese Christian evangelist, social reformer, writer, and public intellectual of the twentieth century, nominated for the Nobel Prize in Literature twice (1947, 1948) and the Nobel Peace Prize three times (1954, 1955, 1956). Appealing to the masses with little knowledge of Christian faith, Kagawa believed that a positive, religio‐aesthetic interpretation of nature and science was a key missiological concern in Japan. He reasoned that a faith rooted in the kenotic movement of incarnation and self‐giving must strongly support the scientific quest. A voracious reader of science and especially biology, he argues for “directionality,” or what he calls “initial purpose” in the long, painful, cosmic journey from matter to life to mind (or consciousness). Through an antireductionistic, a posteriori methodological pluralism that sought to “see all things whole,” this “scientific mystic” employed Christian, Buddhist, Neo‐Confucian, personalist, and vitalist ideas to envision complementary roles for science and religion in modern society.