SPIN is an efficient verification system for models of distributed software systems. It has been used to detect design errors in applications ranging from high-level descriptions of distributed algorithms to detailed code for controlling telephone exchanges. The paper gives an overview of the design and structure of the verifier, reviews its theoretical foundation, and gives an overview of significant practical applications.

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The model checker SPIN

The objective of this paper is to give a comprehensive introduction to applied cryptography with an engineer or computer scientist in mind. The emphasis is on the knowledge needed to create practical systems which supports integrity, confidentiality, or authenticity. Topics covered includes an introduction to the concepts in cryptography, attacks against cryptographic systems, key use and handling, random bit generation, encryption modes, and message authentication codes. Recommendations on algorithms and further reading is given in the end of the paper. This paper should make the reader able to build, understand and evaluate system descriptions and designs based on the cryptographic components described in the paper.

[서평]「Applied Cryptography」

This chapter is devoted to a more detailed examination of game theory. Game theory is an important tool for analyzing strategic behavior, is concerned with how individuals make decisions when they recognize that their actions affect, and are affected by, the actions of other individuals or groups. Strategic behavior recognizes that the decision-making process is frequently mutually interdependent. Game theory is the study of the strategic behavior involving the interaction of two or more individuals, teams, or firms, usually referred to as players. Two game theoretic scenarios were examined in this chapter: Simultaneous-move and multi-stage games. In simultaneous-move games the players effectively move at the same time. A normal-form game summarizes the players, possible strategies and payoffs from alternative strategies in a simultaneous-move game. Simultaneous-move games may be either noncooperative or cooperative. In contrast to noncooperative games, players of cooperative games engage in collusive behavior. A Nash equilibrium, which is a solution to a problem in game theory, occurs when the players’ payoffs cannot be improved by changing strategies. Simultaneous-move games may be either one-shot or repeated games. One-shot games are played only once. Repeated games are games that are played more than once. Infinitely-repeated games are played over and over again without end. Finitely-repeated games are played a limited number of times. Finitely-repeated games have certain or uncertain ends.

An Introduction to Game Theory

Computer communications

A senior undergraduate or graduate level computer science textbook on algorithm design for distributed computer systems.

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An Introduction to Distributed Algorithms

Wireless Sensor Networks are without a doubt one of the central issues in current research topics due to the harsh environmental conditions in which such networks can be deployed and their unique sensor network characteristics,specifically limited power supply, sensing, processing and communication capabilities. Presented with many challenges and design issues that affect the data routing, a need for a fault tolerant routing protocol becomes essential. In this paper, we summarize and highlight the key ideas of existing fault tolerant techniques of routing protocols, survey existing routing protocols proposed to support fault tolerance. Finally, we provide some future research directions in the area of fault tolerance in wireless sensor networks routing.

A Survey on Fault Tolerant Routing Techniques in Wireless Sensor Networks

This paper introduces an accurate analysis using three dimensional Markov chain modeling to compute the IEEE 802.11 DCF performance under heavy traffic conditions and absence of hidden terminals. The proposed model matches the real implementation of the DCF as presented in the standard through considering the impact of retry limits of control and data frames jointly on the performance of DCF mechanism. Moreover, transmission errors are added to the model as constant frame error probabilities. In addition to the throughout efficiency, this analytical analysis calculates the average packet delay, the packet drop probability and the average packet drop time for the DCF access modes, basic and RTS/CTS. We show that our proposed model is a more general model compared to the other models that are presented in the literature, which leads to more accurate performance analysis. Simulation results validate the accuracy of our analytical analysis. Moreover, we prove the generality and validate the correctness of our analysis by showing that other models appeared in literature are special cases from our proposed model. Moreover, the impact of the retry limits and the network size on the performance of IEEE 802.11 DCF is presented.

Three-Dimensional Markov Chain Model for Performance Analysis of the IEEE 802.11 Distributed Coordination Function

The design of good host overload/underload detection and virtual machine (VM) placement algorithms plays a vital role in assuring the smoothness of VM live migration. The presence of the dynamic environment that leads to a changing load on the VMs motivates us to propose a Markov prediction model to forecast the future load state of the host. We propose a host load detection algorithm to find the future overutilized/underutilized hosts state to avoid immediate VMs migration. Moreover, we propose a VM placement algorithm to determine the set of candidates hosts to receive the migrated VMs in a way to reduce their VM migrations in near future. We evaluate our proposed algorithms through CloudSim simulation on different types of PlanetLab real and random workloads. The experimental results show that our proposed algorithms have a significant reduction in terms of service-level agreement violation, the number of VM migrations, and other metrics than the other competitive algorithms.

Markov Prediction Model for Host Load Detection and VM Placement in Live Migration

Wireless mesh networks (WMNs) have emerged recently to extend internet access and other networking services. WMNs routers provide network access to the clients and other networking functions such as routing, and packet forwarding. Bandwidth scarcity is the main challenge that limits the performance of WMNs. Although considerable research has been conducted on spectrum allocation, spectrum management is still considered an important open problem. This problem can be solved using cognitive radio technology that allows radios to intelligently locate free frequencies and use them efficiently. In this work, we propose a new spectrum management scheme that supports local and global management for a wireless network. Our scheme is based on clusters where the coordinator for each cluster manages spectrum information by keeping the required information at cluster level and for the whole network. Our scheme provides robust operation against any cluster head failure, as well as clients mobility.

Cluster-Based Spectrum Management Using Cognitive Radios in Wireless Mesh Network

A rapid increase in wireless communication services has occurred during the last years. Infrastructure-less ad-hoc networks emerge as an interesting option to provide pervasive wireless services, although several challenges must be resolved first. Our paper focuses on issues related to signalling and presence management in mobile wireless ad-hoc networks. We present a framework to use SIP in this kind of networks. The objective of this framework is to allow the users of ad-hoc networks to communicate with each other and exchange instant messages. This framework permits the discovery of participants, the establishment, the publishing and the ending of two-party or multiparty sessions by providing SIP (session initiation protocol) extensions. To cope with the bandwidth limitation problem, it is proposed to unify the network layer routing protocols and the application layer SIP REGISTER methods. Scalability of the framework is improved by introducing a clustering approach that group nodes together into clusters.

Anjali Agarwal

Papers

A Survey on Fault Tolerant Routing Techniques in Wireless Sensor Networks

Three-Dimensional Markov Chain Model for Performance Analysis of the IEEE 802.11 Distributed Coordination Function

Markov Prediction Model for Host Load Detection and VM Placement in Live Migration

Cluster-Based Spectrum Management Using Cognitive Radios in Wireless Mesh Network

A framework to use SIP in ad-hoc networks