Strategic Defense and Attack for Series and Parallel Reliability Systems: Reply on Comment

Kovenock and Roberson’s (2010) paper has the potential to advance the research frontier, but has deficiencies. This paper suggests how Kovenock and Roberson’s (2010) paper can be developed into a more substantial paper. Kovenock and Roberson’s (2010) paper consists of three sections. The first section is an introduction which is OK but has no results. The second section, titled “Model and Main Result”, provides no contribution beyond Hausken (2008a). It consists of equations (1)-(10) which are equivalent to equations developed by Hausken (2008a), and equation (11) which is equivalent to the requirement u≥0 and U≥0 provided after equation (17) in Hausken (2008a). The third section quotes Hausken (2008a) once in one sentence which means that section 3 does not belong as a comment on the paper written by Hausken (2008a). The authors are encouraged to develop a new paper based on many interesting ideas in this note. The new paper should develop further the idea of mixed strategies presented in section 3. The new paper may be titled: “Strategic Defense and Attack for Series and Parallel Reliability Systems when Allowing Mixed Strategies”.Game theory; Reliability theory; OR in military; Conflict; Contest; Network

Strategic Defense and Attack for Series and Parallel Reliability Systems: Comment

The contest-theoretic literature on the attack and defense of networks of targets focuses primarily on pure-strategy Nash equilibria. Hausken\u27s 2008 European Journal of Operational Research article typifies this approach, and many of the models in this literature either build upon this model or utilize similar techniques. We show that Hausken\u27s characterization of Nash equilibrium is invalid for much of the parameter space examined and provides necessary conditions for his solution to hold. The complete characterization of mixed-strategy equilibria remains an open problem, although there exist solutions in the literature for special prominent cases

Strategic Defense and Attack for Series and Parallel Reliability Systems: Reply on Comment

Kovenock and Roberson’s (2010) paper has the potential to advance the research frontier, but has deficiencies. This paper suggests how Kovenock and Roberson’s (2010) paper can be developed into a more substantial paper. Kovenock and Roberson’s (2010) paper consists of three sections. The first section is an introduction which is OK but has no results. The second section, titled “Model and Main Result”, provides no contribution beyond Hausken (2008a). It consists of equations (1)-(10) which are equivalent to equations developed by Hausken (2008a), and equation (11) which is equivalent to the requirement u≥0 and U≥0 provided after equation (17) in Hausken (2008a). The third section quotes Hausken (2008a) once in one sentence which means that section 3 does not belong as a comment on the paper written by Hausken (2008a). The authors are encouraged to develop a new paper based on many interesting ideas in this note. The new paper should develop further the idea of mixed strategies presented in section 3. The new paper may be titled: “Strategic Defense and Attack for Series and Parallel Reliability Systems when Allowing Mixed Strategies”

Strategic Defense and Attack for Series and Parallel Reliability Systems: Reply on Comment

Kovenock and Roberson’s (2010) paper has the potential to advance the research frontier, but has deficiencies. This paper suggests how Kovenock and Roberson’s (2010) paper can be developed into a more substantial paper. Kovenock and Roberson’s (2010) paper consists of three sections. The first section is an introduction which is OK but has no results. The second section, titled “Model and Main Result”, provides no contribution beyond Hausken (2008a). It consists of equations (1)-(10) which are equivalent to equations developed by Hausken (2008a), and equation (11) which is equivalent to the requirement u≥0 and U≥0 provided after equation (17) in Hausken (2008a). The third section quotes Hausken (2008a) once in one sentence which means that section 3 does not belong as a comment on the paper written by Hausken (2008a). The authors are encouraged to develop a new paper based on many interesting ideas in this note. The new paper should develop further the idea of mixed strategies presented in section 3. The new paper may be titled: “Strategic Defense and Attack for Series and Parallel Reliability Systems when Allowing Mixed Strategies”

An attack-defense game on interdependent networks

This paper analyzes the optimal strategies for an attacker and a defender in an attack-defense game on a network consisting of interdependent subnetworks. The defender moves first and allocates its resource to protect the network nodes. The attacker then moves and allocates its resources to attack the network nodes. The binary decision diagram is employed to obtain all potential states of the network system after attack. Considering each of its opponent’s strategies, the game player tries to maximize its own cumulative prospect value. The backward induction method is employed to obtain the game players’ optimal strategies, respectively. Different resource relationships are analyzed to testify the robustness of the main conclusions and players’ risk attitudes are also investigated. Numerical examples are used to illustrate the analysis

Protection optimale des réseaux logistiques contre des attaques

L’évolution des réseaux logistiques s'accompagne du risque inquiétant d'attaques intentionnelles et ils deviennent de plus en plus des cibles potentielles. Il est donc essentiel de les protéger contre ces attaques. Cette thèse développe une méthode d’allocation optimale des ressources de défense des entités de réseaux logistiques contre des attaques intentionnelles, dans le contexte de l’optimisation de la localisation des installations. Cette méthode permet de calculer les dégâts, d’évaluer la valeur d'une cible critique et de répartir de façon optimale des ressources limitées de défense, et ce, en tenant compte de la stratégie de l’attaquant. Trois cas de réseaux logistiques sont étudiés dans cette thèse. Nous considérons tout d’abord le contexte de localisation d’installations à capacité illimitée où une stratégie de protection optimale est sélectionnée. Ensuite, la notion de capacité supplémentaire est utilisée comme moyen de protection indirecte, permettant de réduire le dommage encouru. Enfin, comme l'efficacité d’un réseau logistique est largement déterminée par le bon fonctionnement des entrepôts, ces derniers sont également protégés de la même façon que les usines. Alors que l’objectif du défendeur est de minimiser les dégâts, l’attaquant va chercher à maximiser ces dégâts. Dans les trois cas considérés, le problème sera défini comme un jeu non coopératif min-max à deux périodes dans lequel le défendeur joue en premier. Cela signifie que le défendeur choisit une stratégie à la première période qui minimise le dégât maximal que l’attaquant pourrait causer à la seconde période. Dans le but d’estimer les utilités des joueurs, la méthode proposée évalue l’espérance mathématique de plusieurs coûts : le coût nécessaire à la restauration des installations endommagées, les coûts encourus en raison de l'augmentation possible des coûts de transport suite à des attaques, et le coût dû à une rupture de stock. Un algorithme est développé afin de déterminer la solution d'équilibre et la stratégie de défense optimale. Dans chacun des cas étudiés, notre méthode est comparée à d'autres stratégies. Les résultats obtenus montrent clairement l’efficacité de notre modèle et l’apport de la capacité supplémentaire comme moyen de protection indirecte, ainsi que l’importance de protéger les entrepôts.The evolution of logistic networks is accompanied by the worrisome risk of intentional attacks and these networks increasingly become potential targets. It is essential to protect them against these attacks. This thesis develops a method for the optimal allocation of defensive resources among the entities’ logistic networks to protect against intentional attacks in the context of facility location optimization. This method is developed to calculate the expected damage, evaluate the value of a critical target and optimally distribute the limited defensive resources, taking the attacker’s strategy into account. Three cases of logistics networks are studied in this thesis. We first of all consider the context of the uncapacitated fixed-charge location where a strategy of optimal protection is selected. Then, extra-capacity is used as a means for indirect protection, allowing the reduction of the expected damage. Lastly, as the efficiency and effectiveness in any logistics network is largely determined by the correct operation of the warehouses, the latter are also protected in the same way as the plants. Whereas the defender’s objective is to minimize the damage, the attacker seeks to maximize this damage. In the three cases considered the problem formulation as a two-period game where the defender invests in the first period. This means that the defender selects a strategy in the first period that minimizes the maximum loss the attacker may cause in the second period. A method is developed to evaluate the utilities of the players. This method evaluates many expected costs, including the cost needed to restore disabled facilities, the backorder cost, and the cost incurred because of the change in transportation costs after attacks. An algorithm is developed to find the equilibrium solution and the optimal defence strategy. Our method is compared to other suggested strategies. Obtained results clearly indicate the effectiveness of our model and the indirect protection by extra-capacity deployment, as well as the importance of protecting the warehouses

Understanding the Psychological Pathways to Terrorism & Radicalisation: An Explorative Analysis of the Narratives Given by those Identified as Terrorists or a Radicalised Threat Within the UK

The focus of this study is to gain a deeper insight into the subjective and salient belief systems that are held by those individuals who have previously been detained or arrested under the counter terrorism legislation in the UK. Embedded in the theoretical work of Personal Construct Theory, 8 participants completed an extensive life narrative interview alongside a reparatory grid highlighting core constructs and belief systems. A thematic analysis of the corresponding data was undertaken from which a number of themes were identified. The most prominent emerging theme centred around the concept of empathy and empathic anger. i.e. the participants expressed a strong empathy connection towards those in conflict situations who were seen as victims and equally presented with a strong disapproval or empathic anger towards those who were viewed as aggressors and penultimately responsible for the atrocities. Although further research is required the implications of this emerging theme are significant in developing a holistic understanding of the factors which affect motivational drive of individuals who are 'radicalised'. This study builds upon the theoretical work of Hutson, Long & Page, (2009), Taylor & Horgan, (2006) and Moghaddam, (2005) who respectively identify a series of social and psychological processes which potentially exert an influence on the motivational drive. This study therefore suggests that the modulating factor or the spark which maintains an individual on the path of radicalisation is centred around this notion of empathic anger. This study suggests that individuals who are regarded as a radicalised threat go through a series of subjective experiences and processes are catapulted by this empathic response from merely feeling a grievance to actually rationalising a potential action. A number of additional themes centring around relationships (particularly the father), racisms and the impact of life changing events or trauma were also identified but would benefit from further investigation. The study also attempts to provide a critical look at the discourses around terrorism and radicalisation particularly the subjective and emotive uses of the terminology and the inevitable effects of political biases. A potential area for further study is suggested in the form of a theoretical model which suggests that depending upon the individual’s personal attributes the individual may gravitate towards one of 5 roles i.e. an idealist, soldier, Intellectual-Recruiter, Opportunist-Financier or Patsy. The limitations of the study centre around the relative small sample and the lack of diversity within the sample

Perspectives on the relationship between local interactions and global outcomes in spatially explicit models of systems of interacting individuals

Understanding the behaviour of systems of interacting individuals is a key aim of much research in the social sciences and beyond, and a wide variety of modelling paradigms have been employed in pursuit of this goal. Often, systems of interest are intrinsically spatial, involving interactions that occur on a local scale or according to some specific spatial structure. However, while it is recognised that spatial factors can have a significant impact on the global behaviours exhibited by such systems, in practice, models often neglect spatial structure or consider it only in a limited way, in order to simplify interpretation and analysis. In the particular case of individual-based models used in the social sciences, a lack of consistent mathematical foundations inevitably casts doubt on the validity of research conclusions. Similarly, in game theory, the lack of a unifying framework to encompass the full variety of spatial games presented in the literature restricts the development of general results and can prevent researchers from identifying important similarities between models. In this thesis, we address these issues by examining the relationship between local interactions and global outcomes in spatially explicit models of interacting individuals from two different conceptual perspectives. First, we define and analyse a family of spatially explicit, individual-based models, identifying and explaining fundamental connections between their local and global behaviours. Our approach represents a proof of concept, suggesting that similar methods could be effective in identifying such connections in a wider range of models. Secondly, we define a general model for spatial games of search and concealment, which unites many existing games into a single framework, and we present theoretical results on its optimal strategies. Our model represents an opportunity for the development of a more broadly applicable theory of spatial games, which could facilitate progress and highlight connections within the field