Strongly Essential Coalitions and the Nucleolus of Peer Group Games

Most of the known efficient algorithms designed to compute the nucleolus for special classes of balanced games are based on two facts: (i) in any balanced game, the coalitions which actually determine the nucleolus are essential; and (ii) all essential coalitions in any of the games in the class belong to a prespeci ed collection of size polynomial in the number of players.We consider a subclass of essential coalitions, called strongly essential coalitions, and show that in any game, the collection of strongly essential coalitions contains all the coalitions which actually determine the core, and in case the core is not empty, the nucleolus and the kernelcore.As an application, we consider peer group games, and show that they admit at most 2n - 1 strongly essential coalitions, whereas the number of essential coalitions could be as much as 2n-1. We propose an algorithm that computes the nucleolus of an n-player peer group game in O(n2) time directly from the data of the underlying peer group situation.game theory;algorithm;cooperative games;kernel estimation;peer games

Type Monotonic Allocation Schemes for Multi-Glove Games

Multiglove markets and corresponding games are considered.For this class of games we introduce the notion of type monotonic allocation scheme.Allocation rules for multiglove markets based on weight systems are introduced and characterized.These allocation rules generate type monotonic allocation schemes for multiglove games and are also helpful in proving that each core element of the corresponding game is extendable to a type monotonic allocation scheme.The T-value turns out to generate a type monotonic allocation scheme with nice extra properties.The same holds true for the nucleolus, for in multi glove games these two solutions coincide.allocation;games;t-value

London, UK

This chapter reports the results of a survey on sexual transit crime with 109 respondents. An analysis of the types of sexual harassment experienced by students found that 70 respondents (59 %) reported experiencing some form of sexual harassment at least once in the last three years, either walking to, waiting for, or on board some mode of transport. In total only five students said that they had reported experiences of sexual harassment on transit, and 17 said they had not. These small numbers do not allow a more detailed exploration. Overall, 30% of respondents reported rarely or never feeling safe when either using or waiting for the bus either during the day or after dark, compared to 18% who reported the same for the train or tram. The main precautionary responses identified across both bus and rail were avoiding carrying purses or wallets, and traveling only during daytime. The chapter briefly summarizes the main findings from the case study and makes suggestions for research and practice

Strongly Essential Coalitions and the Nucleolus of Peer Group Games

Most of the known efficient algorithms designed to compute the nucleolus for special classes of balanced games are based on two facts: (i) in any balanced game, the coalitions which actually determine the nucleolus are essential; and (ii) all essential coalitions in any of the games in the class belong to a prespeci ed collection of size polynomial in the number of players.We consider a subclass of essential coalitions, called strongly essential coalitions, and show that in any game, the collection of strongly essential coalitions contains all the coalitions which actually determine the core, and in case the core is not empty, the nucleolus and the kernelcore.As an application, we consider peer group games, and show that they admit at most 2n - 1 strongly essential coalitions, whereas the number of essential coalitions could be as much as 2n-1. We propose an algorithm that computes the nucleolus of an n-player peer group game in O(n2) time directly from the data of the underlying peer group situation.

Exploring spatial and temporal variation in perception of crime and place using crowdsourced data

To advance and widen the scope of research into the perception of crime and place, innovations in technology for data collection can be utilized as research tools. To date, there has been little exploration into these new methods of data capture. This thesis presents the possibilities of using crowdsourced data collection methods for application to research in environmental criminology. The lack of detailed data on people's experiences and movements at a micro geographical and temporal resolution have impeded the exploration of many of the subtleties of the relationship between crime and place, but this data-gap can be filled by creatively applying new technologies for data collection. The core chapters in this thesis give empirical examples, which demonstrate that spatiotemporal data on people's experiences with crime and disorder during their routine activities can be collected and used to study perception of crime and place. By exploring such crowdsourced data from an environmental criminology framework, I demonstrate how fear of crime varies in place and time, dynamically within individuals, which is not reflected in current measurement approaches. I also propose crowdsourced collection of volunteered geographic information as a proxy measurement for within-day fluctuations for active guardianship, possibly highlighting areas of temporarily increased crime risk. Such information also shows promise in identifying when people are likely to encounter signal disorders as part of their everyday routine activities, leading to possible experiences of fear of crime. These findings provide novel insight into fear of crime, signal disorders, and active guardianship, which allows for the exploration of these concepts as situation-dependent, dynamic experiences. Theoretical development of this thesis is the application of the framework of environmental criminology to the study of subjective perceptions, and the possibility to gather empirical data to support this approach is made possible by the methodological developments presented within. This approach serves as a guideline for studying perception in a way that allows for situational prevention measures to be introduced. Making use of new insight into dynamic variation in context allows for identification of areas with temporarily increased risk of crime, disorder or fear of crime. This thesis contributes to theoretical and methodological growth in the study of perception of crime and place by applying crowdsourcing theory and practice to its measurement

Matching structure and bargaining outcomes in buyer–seller networks

We examine the relationship between the matching structure of a bipartite (buyer-seller) network and the (expected) shares of the unit surplus that each connected pair in this network can create. We show that in different bargaining environments, these shares are closely related to the Gallai-Edmonds Structure Theorem. This theorem characterizes the structure of maximum matchings in an undirected graph. We show that the relationship between the (expected) shares and the tructure Theorem is not an artefact of a particular bargaining mechanism or trade centralization. However, this relationship does not necessarily generalize to non-bipartite networks or to networks with heterogeneous link values