Traffic Partition in WDM/SONET Rings to Minimize SONET ADMs

SONET (Synchronous Optical NETworks) add-drop multiplexers (ADMs) are the dominant cost factor in the WDM(Wavelength Division Multiplexing)/SONET rings. The number of SONET ADMs required by a set of traffic streams is determined by the routing and wavelength assignment of the traffic streams. Previous works took as input the traffic streams with routings given a priori and developed various heuristics for wavelength assignment to minimize the SONET ADM costs. However, little was known about the performance guarantees of these heuristics. This paper contributes mainly in two aspects. First, in addition to the traffic streams with pre-specified routing, this paper also studies minimizing the ADM requirement by traffic streams without given routings, a problem which is shown to be NP-hard. Several heuristics for integrated routing and wavelength assignment are proposed to minimize the SONET ADM costs. Second, the approximation ratios of those heuristics for wavelength assignment only and those heuristics for integrated routing and wavelength assignment are analyzed. The new Preprocessed Iterative Matching heuristic has the best approximation ratio: at most 3/2.     

Re-evaluating the Community Question from a German perspective

The far-reaching effects of the social systemic division of labor on the organization and contents of primary ties make the Community Question an important issue for many sociologists. This paper looks at the personal embeddedness of families in three German cities (Berlin, Hamburg, and Stuttgart) and examines the Community Question with data collected at the end of 2003. It is based on the theoretical views of Wellman [Wellman, B., 1979. The community question. The intimate networks of East Yorkers. American Journal of Sociology 84, 1201–1231], who used a network analysis perspective to conceptualize “the Community Question”. The results of this German study generally support the results of Wellman's second East York Study. However, the network structures analyzed in my study vary from the three ideal-type models. Cluster analysis shows that Wellman's typology can be replicated relatively well in Germany. In contrast to traditional discourse related to the Community Question, particular network types are not associated with low levels of social relations. Moreover, structural factors do not explain the existence of different network types. Thus, the networks are not a product of only one community model. They suggest that it is less helpful to talk about “Saved”, “Lost”, or “Liberated” communities than it is to regard communities as a mixture of strongly-knit nuclear clusters and of broader, sparsely-knit relations that provide access to different groups and their resources.     

Multivariate log-skewed distributions with normal kernel and their applications

We introduce two classes of multivariate log-skewed distributions with normal kernel: the log canonical fundamental skew-normal (log-CFUSN) and the log unified skew-normal. We also discuss some properties of the log-CFUSN family of distributions. These new classes of log-skewed distributions include the log-normal and multivariate log-skew normal families as particular cases. We discuss some issues related to Bayesian inference in the log-CFUSN family of distributions, mainly we focus on how to model the prior uncertainty about the skewing parameter. Based on the stochastic representation of the log-CFUSN family, we propose a data augmentation strategy for sampling from the posterior distributions. This proposed family is used to analyse the US national monthly precipitation data. We conclude that a high-dimensional skewing function lead to a better model fit.     

The sand lizard moves downtown – habitat analogues for an endangered species in a metropolitan area

Urban Ecosystems - Urbanisation can be dangerous to biological diversity, but on the other hand cities can enhance local and regional biodiversity by providing habitat analogues for many –...     

Long memory estimation for complex-valued time series

Statistics and Computing - Long memory has been observed for time series across a multitude of fields, and the accurate estimation of such dependence, for example via the Hurst exponent, is crucial...     

Participant roles in preschool bullying: The impact of emotion regulation,social preference,and quality of the teacher–child relationship

The present work investigated whether emotion regulation and social preference were associated with participant roles in bullying as a function of the quality of the relationship with teachers. Participants were 332 children (172 boys), in the age of 42–76 months (M = 58.74; SD = 7.84). Peer nominations were employed to assess social preference and participant roles (bullying, victimization, defending the victim, and outsider behavior). Teachers completed the Emotion Regulation Checklist, which yields the dimensions of emotion regulation and lability/negativity, and the Student – Teacher Relationships Scale, to evaluate conflict and closeness with the teacher. Multilevel models highlighted that emotional lability was positively associated with bullying and outsider behavior, emotion regulation was positively related to bullying and defending behavior, and social preference was negatively associated with bullying and victimization and positively with defending behavior. Interactions indicated that lability and low social preference were associated with bullying, and emotion regulation with outsider behavior, in children with a conflictual relationship with the teacher whereas social preference was related to defending behavior in children with a close relationship with the teacher. Results are discussed highlighting the importance of the quality of teacher–child relationship and the relevance of intervention programs aimed at promoting social wellbeing in preschool.     

Decomposing the increase in men’s time on childcare during the great recession

In this paper, I examine the time men spent on childcare during the recession of 2007–2009. The recession provides a sudden change in the employment opportunities of men relative to women in the United States. Using the American Time Use Survey and the linked Current Population Survey, I show that this lopsided shock to employment opportunities was accompanied by an increase in the average amount of time men spent on childcare. In particular, men’s average time on physical care for children increased during the recession; this is an element of childcare that men perform less than women. I decompose the total change in average time on childcare into behavioral, compositional, and between group change. A behavioral change among employed men accounted for the majority of the total increase in the average time spent on childcare; among men who are out of the labor force, the increase is entirely due to compositional changes.     

In search of rigor, relevance, and legitimacy: what drives the impact of publications?

In this study, we introduce the concept of legitimacy to the rigor-relevance debate and investigate empirically how rigor, relevance, and legitimacy are related to the process of knowledge dissemination within a research field. We argue that this analysis has been a missing piece in the debate on rigor and relevance when institutional logics about what constitutes both elements lead researchers to act according to what they perceive to be appropriate behavior in the research field. We draw on insights from the micro and macro levels of institutional theory to show how researchers aiming to bestow legitimacy on their own work conform to these “rules of the game”. Using meta-analytical techniques, we focus on the field of strategic entrepreneurship and analyze how rigor- and relevance-related characteristics of studies in this field are linked to their legitimacy and therefore to the impact they have in the research community.     

Observed and parent‐reported conscience in childhood: Relations with bullying involvement in early primary school

This exploratory study aimed to examine which components of early childhood conscience predicted bullying involvement around school entry. In the population‐based Generation R Study, teacher reports of bullying involvement and parent reports of conscience were available for 3,244 children (M age = 6.7 years). Higher levels of overall conscience predicted lower bullying perpetration scores, independently of intelligence quotient, temperamental traits and sociodemographic characteristics. Particularly, the subscales guilt, confession, and internalized conduct, and to a lesser extent empathy, predicted bullying perpetration. Conscience was not related to victimization. Similar results were found using observations during so‐called ‘cheating games’ (subsample N = 450 children). Findings suggest that improving children's understanding of moral standards and norms may be a potential target for bullying intervention programs in early primary school.