The graphs with the max-Mader-flow-min-multiway-cut property

We are given a graph $G$, an independant set $\mathcal{S} \subset V(G)$ of \emph{terminals}, and a function $w:V(G) \to \mathbb{N}$. We want to know if the maximum $w$-packing of vertex-disjoint paths with extremities in $\mathcal{S}$ is equal to the minimum weight of a vertex-cut separating $\mathcal{S}$. We call \emph{Mader-Mengerian} the graphs with this property for each independant set $\mathcal{S}$ and each weight function $w$. We give a characterization of these graphs in term of forbidden minors, as well as a recognition algorithm and a simple algorithm to find maximum packing of paths and minimum multicuts in those graphs

Multi-hop Byzantine reliable broadcast with honest dealer made practical

We revisit Byzantine tolerant reliable broadcast with honest dealer algorithms in multi-hop networks. To tolerate Byzantine faulty nodes arbitrarily spread over the network, previous solutions require a factorial number of messages to be sent over the network if the messages are not authenticated (e.g., digital signatures are not available). We propose modifications that preserve the safety and liveness properties of the original unauthenticated protocols, while highly decreasing their observed message complexity when simulated on several classes of graph topologies, potentially opening to their employment

A study of young firm performance in France between 2006 and 2009 using the process theory of organisation

This thesis studies the performance of a cohort of French firms between 2006 and 2009 using a theoretical framework developed for this purpose. This framework is based on the author’s entrepreneurial experience and conviction that firm performance is dependent on solving a managerial problem with two components: (i) an entrepreneurial component which focuses on creating market power with respect to customer wants, resources, means of production, and technology and (ii) an organisational component aiming to implement adequate labour division and coordination and motivation mechanisms in the firm. Solving both aspects of the managerial problem in firms is expected to increase frim performance over time. This book describes the origins of the managerial problem in the economic literature, studies its dual organisational and entrepreneurial aspect, and measures its effect on firm performance.:INTRODUCTION PART I: LITERATURE REVIEW, RESEARCH QUESTION, AND RESEARCH PLAN CHAPTER 1 : LITERATURE REVIEW CHAPTER 2 : RESEARCH QUESTION CHAPTER 3 : RESEARCH PLAN PART II: THEORETICAL DEVELOPMENT CHAPTER 4 : THE PROCESS THEORY OF ORGANISATION CHAPTER 5 : A MODEL OF FIRM PERFORMANCE CHAPTER 6 : LEVERAGES ON FIRM PERFORMANCE CHAPTER 7 : THE MANAGERIAL PROBLEM PART III: EMPIRICAL ANALYSIS CHAPTER 8 : BUILDING A MODEL TO ASSESS FIRM PERFORMANCE CHAPTER 9 : ENTREPRENEURIAL ABILITY AND ITS CHARACTERISTICS CHAPTER 10 : ORGANISATIONAL ABILITY AND ITS CHARACTERISTICS CHAPTER 11 : THE IMPACT OF MANAGEMENT ON FIRM PERFORMANCE PART IV: OUTLOOK APPENDIX A: THE AUSTRIAN SCHOOL OF THOUGHTS AND ITS EVOLUTION APPENDIX B: A CALCULATED EXAMPLE OF FIRM PERFORMANCE WITH NESTED PROCESSES APPENDIX C: ON STRUCTURING AND DRIVING THE FIRM APPENDIX D: LANDMARKS TO UNDERSTANDING THE ENTREPRENEURIAL PROCESS APPENDIX E: DESCRIPTIVE STATISTICS APPENDIX F: MODEL SPECIFICATION REFERENCE

Multi-hop Byzantine Reliable Broadcast with Honest Dealer Made Practical

We revisit Byzantine tolerant reliable broadcast with honest dealer algorithms in multi-hop networks. To tolerate Byzantine faulty nodes arbitrarily spread over the network, previous solutions require a factorial number of messages to be sent over the network if the messages are not authenticated (e.g. digital signatures are not available). We propose modifications that preserve the safety and liveness properties of the original unauthenticated protocols, while highly decreasing their observed message complexity when simulated on several classes of graph topologies, potentially opening to their employment

Multi-hop Byzantine Reliable Broadcast with Honest Dealer Made Practical

We revisit Byzantine tolerant reliable broadcast with honest dealer algorithms in multi-hop networks. To tolerate Byzantine faulty nodes arbitrarily spread over the network, previous solutions require a factorial number of messages to be sent over the network if the messages are not authenticated (e.g. digital signatures are not available). We propose modifications that preserve the safety and liveness properties of the original unauthenticated protocols, while highly decreasing their observed message complexity when simulated on several classes of graph topologies, potentially opening to their employment

Finding Second-Order Clubs

Modeling data entities and their pairwise relationships as a graph is a popular technique to visualizing and mining information from datasets in a variety of fields such as social networks, biological networks, web graphs, and document networks. A powerful technique in this setting involves the detection of clusters. Clique, a subset of pairwise adjacent vertices, is often viewed as an idealized representation of a cluster. However, in the presence of errors in the data on which the graph is based, clique requirement may be too restrictive, resulting in small clusters or clusters that miss key members. Consequently, graph-theoretic clique generalizations based on the principle of relaxing elementary structural properties of a clique have been proposed in diverse fields to describe clusters of interest. For example, an s-club is a distance-based clique relaxation originally introduced in social network analysis to model cohesive social subgroups. In this dissertation, we consider low-diameter clusters that require another property like robustness, heredity, or connectedness (parameterized by r) to hold, in addition to the diameter. Specifically, we study s-clubs with side-constraints to make them less “fragile”, i.e., less susceptible to increase in the diameter if vertices (and edges) are deleted. The overall goal of this dissertation is to develop effective exact algorithms with an emphasis on s = 2, 3, 4 and low values of r to solve the maximum r-robust s-club and r-hereditary s-club problems on moderately large instances (around 10,000 vertices and less than 5% density). We analyze the complexity of the associated feasibility testing and optimization problems. Cut-like formulations are proposed for the maximum r-robust s-club problem with r ≥ 2 and s ∈ {2, 3, 4}. We explore preprocessing techniques and develop a graph decomposition approach for solving such problems. The computational benefits of each of the algorithmic ideas are empirically evaluated through our computational studies. Our approach permits us to solve problems optimally on very large and sparse real-life networks