Nonparametric self-exciting models for computer network traffic

Statistics and Computing - Connectivity patterns between nodes in a computer network can be interpreted and modelled as point processes where events in a process indicate connections being...     

Reactive and proactive aggression in children with and without ADHD and negative emotional lability

Children with attention‐deficit/hyperactivity disorder (ADHD) exhibit marked difficulty with frequent and intense shifts in negative or positive emotions, referred to as emotional lability. This study examines the relationships between negative emotional lability (NEL), ADHD, and reactive and proactive aggression. A community sample of 96 children (53 with ADHD, 43 control) ages 8–12 and their parents completed a baseline session include a diagnostic structured interview and the Reactive–Proactive Aggression Questionnaire (RPAQ). Parents then rated their child's NEL using the Positive and Negative Affect Scale as part of an Ecological Momentary Assessment protocol 3 times a day for 28 days. Seventy‐three participants (37 with ADHD, 36 control) completed the RPAQ at follow‐up. Hierarchical regression analyses indicated that NEL significantly and independently estimates reactive aggression at baseline and follow‐up, regardless of ADHD status. NEL and ADHD status significantly estimates concurrent proactive aggression, but not at follow‐up. Results of this study suggest that NEL accounts for a significant amount of the variability in reactive aggression, a common difficulty in children with ADHD. Further, individuals that are reportedly emotionally labile become more reactively aggressive over time. Both ADHD diagnostic and NEL are predictors of proactive aggression at baseline, although no interaction occurred.     

The Determinants of Retail Productivity: A Critical Review of the Evidence

This paper discusses the literature on the established determinants of productivity in the retail sector. It also draws attention to some neglected strands of research which provide useful insights into strategies that could allow productivity enhancements in this area of the economy. To date, very few attempts have been made to integrate different specialisms in order to explain what drives productivity in retail. Here this paper rectifies this omission by putting together studies from economics, geography, knowledge management and employment studies. It is the authors’ view that quantitative studies of retail productivity should focus on total factor productivity in retailing as the result of competition/composition effects, planning regulations, information and communications technology, the multinational operation element and workforce skills. Further, the fact that retail firms possess advantages that are transferable between locations suggests that investment in strategies enhancing the transfer of explicit and tacit knowledge between and within businesses are crucial to achieve productivity gains.     

Core self-evaluations mediate the association between leaders' facial appearance and their professional success: Adults' and children's perceptions

Although the link between facial appearance and success is well established, the mechanisms responsible for this association have remained elusive. Evolutionary theory suggests that perceived leadership characteristics should be important for men's self-concept. Drawing on implicit leadership theory and evolutionary perspectives, we therefore examined the associations between first impressions based on facial appearance, core self-evaluations (CSEs), leadership role occupancy, and career success among a sample of working men. In Study 1, we found that CSEs mediated the relationship between individuals' facial appearance and measures of their success as leaders. In Study 2, we replicated these results using children's ratings of facial appearance, thus suggesting that basic properties of the targets' faces communicated their leadership ability more than the perceivers' life experience or acquired knowledge. These results suggest that people may use facial appearance as a diagnostic tool to determine the leadership ability of others.     

互补品天才

安德烈和爱德华当初是怎么想的？ 1900年，就在两兄弟刚刚接管家族设在克莱蒙一费朗市橡胶生意之后不久，他们决定为旅行者出版一本指导手册。在他们的《米其林指南》一书当中，作者提供了大量加油站、酒店、餐厅和观光景点的信息，并配有详尽的地图和旅行提示。该书第一版印刷了35000册，米其林公司免费将其发放给那些感兴趣的读者们。他们的这一做法后来被证明是一个极其天才的举动。     

Dynamic Pricing to Minimize Maximum Regret

We consider a dynamic pricing problem that involves selling a given inventory of a single product over a short, two‐period selling season. There is insufficient time to replenish inventory during this season, hence sales are made entirely from inventory. The demand for the product is a stochastic, nonincreasing function of price. We assume interval uncertainty for demand, that is, knowledge of upper and lower bounds but not a probability distribution, with no correlation between the two periods. We minimize the maximum total regret over the two periods that results from the pricing decisions. We consider a dynamic model where the decision maker chooses the price for each period contingent on the remaining inventory at the beginning of the period, and a static model where the decision maker chooses the prices for both periods at the beginning of the first period. Both models can be solved by a polynomial time algorithm that solves systems of linear inequalities. Our computational study demonstrates that the prices generated by both our models are insensitive to errors in estimating the demand intervals. Our dynamic model outperforms our static model and two classical approaches that do not use demand probability distributions, when evaluated by maximum regret, average relative regret, variability, and risk measures. Further, our dynamic model generates a total expected revenue which closely approximates that of a maximum expected revenue approach which requires demand probability distributions.     

Theorizing Managerial Work: a Pragmatic Pluralist Approach to Interdisciplinary Research

Management research is especially open to the benefits of using insights from a variety of social science disciplines but it should not use these indiscriminately. A strategy of pragmatic pluralism is proposed as a way of ensuring that concepts taken from different social science paradigms or disciplines are drawn together into a single coherent perspective to shape the particular study to which they relate. This is illustrated with reference to an ethnographic study of managerial work carried out by the author.     

The ℓ1 oblique procrustes problem

In this paper, we reconsider the well-known oblique Procrustes problem where the usual least-squares objective function is replaced by a more robust discrepancy measure, based on the ₁ norm or smooth approximations of it.We propose two approaches to the solution of this problem. One approach is based on convex analysis and uses the structure of the problem to permit a solution to the ₁ norm problem. An alternative approach is to smooth the problem by working with smooth approximations to the ₁ norm, and this leads to a solution process based on the solution of ordinary differential equations on manifolds. The general weighted Procrustes problem (both orthogonal and oblique) can also be solved by the latter approach. Numerical examples to illustrate the algorithms which have been developed are reported and analyzed.     

Resources and strategies of interest groups and industry representatives involved in federal forest policy

This study analyzes the resources and strategies of public interest groups and industry representatives involved in federal forest policy in the state of Oregon during the early 1990s. While many studies have examined the role of interest groups in the policy process, few have compared empirically the resources available and strategies pursued by industry representatives and public interest groups in a particular policy domain. Utilizing survey data from 133 business representatives and 326 public interest groups involved in federal forest policy, the study argues that public interest group influence derives primarily from the ability to mobilize human resources; the financial resources of these groups tend to be modest. Industry and industry-supported groups, in contrast, possess considerable financial power while enjoying less support from the public. Consequently, industry interests tend to focus their efforts on more traditional forms of influence such as the persistent lobbying of natural resource agencies and elected officials. Public interest groups, in contrast, tend to devote considerable efforts to building public support in urban core areas to build the capacity to pressure governmental decision-makers.     

THE FAMILY FIRO MODEL: A MODEST PROPOSAL FOR ORGANIZING FAMILY TREATMENT

This paper presents a model for organizing family issues and family treatment. Schutz's FIRO model is offered as a framework for organizing family issues into inclusion, control and affection categories. Following Schutz's theory of group development, we propose that inclusion, control and affection constitute a logical hierarchy of core issues to be dealt with in treating multiproblem families-inclusion first, then control, and then affection (intimacy). Furthermore, we propose that the FIRO model can be used to organize theories of family therapy. We attempt to demonstrate that different family therapies are best suited for one of the three core issues of family interaction. We advocate an "intelligent eclecticism" based on the premise that when an issue is appropriately matched with a therapy, therapeutic effectiveness should be enhanced. We also discuss implications of our Family FIRO model for clinical practice.