A shelf-space optimization model when demand is stochastic and space-elastic

The more customer demand is impulse-driven, the more it is space-dependent and the more it is subject to variation. We investigate the corresponding problem of retail shelf-space planning when demand is stochastic and sensitive to the number and position of facings. We develop a model to maximize a retailer׳s profit by selecting the number of facings and their shelf position under the assumption of limited space. The model is particularly applicable to promotional or temporary products.We develop the first optimization model and solution approach that takes stochastic demand into account, since the current literature applies deterministic models for shelf-space planning. By the means of an innovative modeling approach for the case with space- and positioning effects and the conversion of our problem into a mixed-integer problem, we obtain optimal results within very short run times for large-scale instances relevant in practice. Furthermore, we develop a solution approach to account for cross-space elasticity, and solve it using an own heuristic, which efficiently yields near-optimal results. We demonstrate that correctly considering space elasticity and demand variation is essential. The corresponding impacts on profits and solution structures become even more significant when space elasticity and stochastic demand interact, resulting in up to 5% higher profits and up to 80% differences in solution structures, if both effects are correctly accounted for. We develop an efficient modeling approach, compare the model results with approaches applied in practice and derive rules-of-thumb for planners.     

Approach and Positive Affect in Toddlerhood Predict Early Childhood Behavior Problems

The aim of the study was to examine the moderating role of positive affect on the relation between approach behaviors and adjustment outcomes. One hundred eleven toddlers participated in a laboratory assessment of approach and positive affect at 24 months. Behavior problems were reported by a parent in the fall of the child's kindergarten year. Results supported our hypotheses that children who displayed high approach and high positive affect in both non‐threat and low‐threat contexts were rated as higher in externalizing behavior problems. On the other hand, for children showing low positive affect, increases in approach in a moderate‐threat context lowered the risk of developing internalizing behavior problems. Implications for these findings are discussed, including methodological considerations of differences among eliciting contexts and advantages of separating positive affect and approach.     

Is Tattooing a Risk Factor for Adolescents’ Criminal Behavior? Empirical Evidence from an Administrative Data Set of Juvenile Detainees in Taiwan

Juvenile crime affects not only the victims of the crime but also the delinquents’ future. How to prevent adolescent criminal behavior has become an important public policy issue. This study contributes to this interesting issue by examining the relationship between tattooing and adolescents’ criminal behavior. In particular, this study investigates whether or not having a tattoo/tattoos is connected to the incidence of various criminal activities, including: larceny, robbery, fraud, assault, drug use, and homicide. A unique sample of 973 juvenile detainees drawn from the administrative profiles in Taiwan and the coarsened exact matching method were utilized. Results show that compared to their nontattooed counterparts, tattooed juvenile detainees were significantly more likely to commit fraud, assault, drug abuse, and homicide by 3%, 13%, 9%, and 9%, respectively. In contrast, tattooing was not significantly associated with larceny or robbery. From a policy perspective, given the significant link between tattooing and criminal behavior, the presence of a tattoo in adolescents may serve as a valuable indicator regarding adolescents’ high probability of committing crimes.     

An access network design problem with end-to-end QoS constraints

In this paper, we present an access network design problem with end-to-end quality of service (QoS) requirement. The problem can be conceptualized as a two-level hierarchical location-allocation problem on the tree topology with nonlinear side constraints. The objective function of the nonlinear mixed integer programming model minimizes the total cost of switch and fiber cable, while satisfying demand within the prescribed level of QoS. By exploiting the inherent structure of the nonlinear QoS constraints, we develop linearization techniques for finding an optimal solution. Also, we devise an effective exact optimal algorithm within the context of disjunctive constraint generation. We present promising computational results that demonstrate the effectiveness of the proposed solution procedure.     

Transient detailed balance and product form for reaction networks

This paper explores the boundary of the set of reaction networks that have an exact transient (truncated) multidimensional Poisson or product-form distribution for the number of particles of different types. Motivated by the birth–death process, we introduce the notions of transient detailed balance and delay functions, and use these notions to obtain the novel transient product-form distribution in a coagulation-fragmentation process for polymers with a tree-like structure from that of the pure coagulation process.     

An integrative model of leadership behavior

Decades of questionnaire and interview studies have revealed various leadership behaviors observed in successful leaders. However, little is known about the actual behaviors that cause those observations. Given that lay observers are prone to cognitive biases, such as the halo effect, the validity of theories that are exclusively based on observed behaviors is questionable. We thus follow the call of leading scientists in the field and derive a parsimonious model of leadership behavior that is informed by established psychological theories. Building on the taxonomy of Yukl (2012), we propose three task-oriented behavior categories (enhancing understanding, strengthening motivation and facilitating implementation) and three relation-oriented behavior categories (fostering coordination, promoting cooperation and activating resources), each of which is further specified by a number of distinct behaviors. While the task-oriented behaviors are directed towards the accomplishment of shared objectives, the relation-oriented behaviors support this process by increasing the coordinated engagement of the team members. Our model contributes to the advancement of leadership behavior theory by (1) consolidating current taxonomies, (2) sharpening behavioral concepts of leadership behavior, (3) specifying precise relationships between those categories and (4) spurring new hypotheses that can be derived from existing findings in the field of psychology. To test our model as well as the hypotheses derived from this model, we advocate the development of new measurements that overcome the limitations associated with questionnaire and interview studies.     

茶叶供应者质量安全认知与行为分析——基于浙江500位茶叶供应者的问卷调查

茶叶质量安全问题制约了中国茶叶产业的可持续发展。通过构建茶叶供应质量控制主要环节结构体系,对各环节供应者质量安全认知与质量控制行为考察,利用TOPSIS模型对茶叶供应质量控制关键点进行分析,归纳出当下茶叶供应链质量控制关键环节、重要环节和普通环节。研究表明:茶叶种植者、加工者质量安全基本认知程度较低;供应者在产前环节、种植管理环节、加工环节、储运销售环节中的部分质量控制行为薄弱。茶叶供应者素质良莠不齐是质量安全认知层次不同的主要原因,因此,需对不同供应者有针对性地进行质量安全认知强化。     

The shifting landscape of LGBT organizational research

Over the past generation, sexual minorities—particularly lesbian, gay, bisexual, and transgender (LGBT) persons—have gained increased visibility in the public arena. Yet organizational research has lagged behind in recognizing and studying this category of organizational members. This article offers a critical review of this growing body of research. More specifically, we identify and discuss four dominant scholarly frames that have informed LGBT organizational research from the late nineteenth century to date. The frames include a “medical abnormality,” “deviant social role,” “collective identity,” and “social distinctiveness” view of sexual minorities. We argue that these frames have profoundly shaped the scope and range of organizational scholarship devoted to sexual minorities by showing that scholars using such contrasted frames have been drawn to very different research questions with respect to sexual minorities. We document and discuss the main and contrasted questions asked within each of these frames and show how they have both enabled and constrained LGBT organizational research. We conclude by calling for more attention to the frames organizational scholars adopt when studying sexual minorities, but also for more research on both minority and majority sexual orientations in organizations.     

高职高专学生金工实习模式的探索与实践

金工实习是高职高专学生实现理论知识与实践过程相结合的重要途径,对学生树立正确的就业观,掌握职业技能至关重要。以行为导向教育思想为基础,探讨了高职高专学生体验真实工程过程,获取真实职业能力的金工实习模式,以真正培养出既有理论基础更有实践能力的高技能人才。     

Awareness of low self-control: Theory and evidence from a homeless shelter

Survey measures of self-control provide a potential low-cost alternative to incentivized elicitation. However, asking respondents to introspect on their self-control problems may instead measure their awareness of them, especially in populations with low self-control. We illustrate this with the Ameriks, Caplin, Leahy, and Tyler (2007) survey, which captures self-control problems through the deviation between self-reported ideal and predicted behavior (Expected Deviation, ED). Previous empirical evidence from high income or highly educated populations correlates larger ED with worse outcomes. We theoretically show that the reverse will be true in settings where awareness can play a large role: when self-control is low and costly commitment devices are available. We empirically show that, for residents of a homeless shelter, ED is positively correlated to savings in shelter lockboxes, a costly commitment device. This correlation is stronger for those likely to experience more self-control problems: individuals with past addiction problems.