“Minimax length links” of a dissimilarity matrix and minimum spanning trees

A theorem is proved stating that the set of all minimax links, defined as links minimizing, over paths, the maximum length of links in any path connecting a pair of objects comprising nodes in an undirected weighted graph, comprise the union of all minimum spanning trees of that graph. This theorem is related to methods of fitting network models to dissimilarity data, particularly a method called Pathfinder due to Schvaneveldt and his colleagues, as well as to single linkage clustering, and results concerning the relationship between minimum spanning trees and single linkage hierarchical trees.Acknowledgments: The author thanks Phipps Arabie, Lawrence J. Hubert, and K. Christoph Klauer for a number of helpful suggestions and comments on various aspects of this paper.     

不同年级青少年的友伴网络结构

选择小六、初二和高一学生共１０４０名作被试,采用十项友伴提名法,要求被试至多提名１０个友伴,通过网络分析,从友伴提名数、友伴选择的双向性两个方面探讨不同年级学生友伴网络结构,结果显示,青少年平均拥有６～７个友伴,在这些友伴关系中,单向选择占明显的优势。性别、年级和学习成绩之间的交互作用以及父母受教育水平和家庭结构之间的交互作用（包括两两之间的交互作用）除个别外,均不明显;性别、年级和学习成绩的主效应较明显,而父母受教育水平和家庭结构的主效应却不明显。     

Peer networks and bullying in schools

This study looked at how the social constellations in school classes relate to bullying problems. Using peer-evaluation questionnaires, the peer networks of children with different participant roles (such as victim, bully, assistant of bully, reinforcer of bully, defender of victim, outsider) were explored. The subjects were 459 sixth-grade-children (218 girls, 241 boys), aged 11 to 12 years, in Finland. The main findings were: 1) Children who tended to behave in either similar or complementary participant roles in situations of bullying formed networks with each other. The individual child's behavior in bullying situations was strongly connected to how the members of his/her network behaved in such situations. 2) Bullies, assistants, and reinforcers belonged to larger networks than did defenders, outsiders and victims. 3) Children outside the networks were most often victims. It was concluded that behavior in bullying situations can be said to be one feature around which the peer networks in school classes are organized. Thus prevention, as well as intervention strategies against bullying should focus not only on individual children, but also on the wider social context of the class.     

Deconstructing trait anxiety: a network perspective

Background and objectives: For decades, the dominant paradigm in trait anxiety research has regarded the construct as signifying the underlying cause of the thoughts, feelings, and behaviors that supposedly reflect its presence. Recently, a network theory of personality has appeared. According to this perspective, trait anxiety is a formative construct emerging from interactions among its constitutive features (e.g., thought, feelings, behaviors); it is not a latent cause of these features.

Design: In this study, we characterized trait anxiety as a network system of interacting elements.

Methods: To do so, we estimated a graphical gaussian model via the computation of a regularized partial correlation network in an unselected sample (N?=?611). We also implemented modularity-based community detection analysis to test whether the features of trait anxiety cohere as a single network system.

Results: We find that trait anxiety can indeed be conceptualized as a single, coherent network system of interacting elements.

Conclusions: This radically new approach to visualizing trait anxiety may offer an especially informative view of the interplay between its constitutive features. As prior research has implicated trait anxiety as a risk factor for the development of anxiety-related psychopathology, our findings also set the scene for novel research directions.     

What if they are right? Network approval,expectations, and relationship maintenance behaviors

This study drew on uncertainty reduction and decision‐making theories to investigate how perceptions of approval of romantic relationships from family and friends can influence romantic partners' dynamics. Using a dyadic approach, the authors examined whether expectations of a partner's behavior in the relationship mediated the associations between perceived social network approval and relationship maintenance behaviors in a sample of 137 couples. The actor–partner interdependence mediation model (APIMeM) was applied. Results showed that women's and men's perceptions of approval from their own and their partner's network were associated with their own level of expectations of their partner's behaviors. In turn, women's and men's expectations were associated with their own and their partner's maintenance behaviors.     

Modelling the human lane-change execution behaviour through Multilayer Perceptrons and Convolutional Neural Networks

Driving is a highly complex task that involves the execution of multiple cognitive tasks belonging to different levels of abstraction. Traffic emerges from the interaction of a big number of agents implementing those behaviours, but until recent years, modelling it by the interaction of these agents in the so called micro-simulators was a nearly impossible task as their number grows. However, with the growing computing power it is possible to model increasingly large quantities of individual vehicles according to their individual behaviours. These models are usually composed of two sub-models for two well-defined tasks: car-following and lane-change. In the case of lane-change the literature proposes many different models, but few of them use Computational Intelligence (CI) techniques, and much less use personalization for reaching individual granularity. This study explores one of the two aspects of the lane-change called lane-change acceptance, where the driver performs or not a lane-change given his intention and the vehicle environment. We demonstrate how the lane-change acceptance of a specific driver can be learned from his lane change intention and surrounding environment in an urban scenario using CI techniques such as feed-forward Artificial Neural Network (ANN). We work with Multilayer Perceptron (MLP) and Convolutional Neural Networks (CNN) architectures. How they perform one against the other and how the different topologies affect both to the generalization of the problem and the learning process are studied.     

Enterprise credit risk evaluation based on neural network algorithm

To explore the enterprise credit risk evaluation, the application effect of several common neural network models in Chinese small and medium-sized enterprise data sets was compared and the optimal parameters for each model were determined. In addition, the classification accuracy and the applicability of the model were compared, and finally the common problem of optimization neural network algorithm based on population was solved: need to determine the dimensions in advance. The experimental results showed that the probabilistic neural network (PNN) had the minimum error rate and second types of errors, while the PNN model had the highest AUC value and was robust. To sum up, the algorithm makes some contributions to solve the financing problem of small and medium-sized enterprises in China.     

Attentional orienting and awareness: evidence from a discrimination task

We used several cue–target SOAs (100, 500, 1000 ms) and three different degrees of cue predictability (Non-predictive-50%, Predictive-75%, Counter-predictive-25%), to investigate the role of awareness of cue–target predictability on cueing effects. A group of participants received instructions about the informative value of the cue, while another group did not receive such instructions. Participants were able to extract the predictive value of a spatially peripheral cue and use it to orient attention, whether or not specific instructions about the predictive value of the cue were given, and no matter their ability to correctly report it in a post-test questionnaire. In the non-predictive block, bad estimators who received no instructions showed regular cueing effects, while good estimators exhibited smaller and non-significant facilitatory effects at the short SOA and an absence of significant IOR at longer SOAs. However, for the instructions group, the pattern of results reversed.     

Un regard structural sur l’inégalité des genres au travail : La causalité des différences « genrées » dans les caractéristiques de réseau de l’employé

This study aims at identifying gender differences in network structure and, hence, at understanding the underlying nature of gender inequalities in organisations. The hypotheses address four ego-network characteristics: network size and density, and ego’s centrality and brokerage. Contrary to the existing body of literature, none significant isolated gender difference in network structure is identified. Instead, those gender differences are triggered exclusively by organisational status, that is to say, they are due to the increased level of power. Thus, organisational status is considered as moderating the relationship between gender and network structure’s characteristics. Some further perspectives are suggested to clarify and generalise the phenomena observed.