@conference {
	title = {Maximum Entropy Models, Dynamic Games and Robust Output Feedback Control of Nonlinear Systems},
	author = {Baras, John S.},
	year = {2006},
	month = {12/2006},
	abstract = {In this paper, we develop a framework for designing controllers for general, partially observed discretetime nonlinear systems which are robust with respect to uncertainties (disturbances). A general deterministic model for uncertainties is introduced, leading to a dynamic game formulation of the robust control problem. This problem is solved using an appropriate information state. We derive a partially observed nonlinear stochastic model as the maximum entropy stochastic model for the nonlinear system. A risk-sensitive stochastic control problem is formulated and solved for this partially observed stochastic model. The two problems are related using small noise limits. These small noise asymptotics are for the first time justified as the appropriate randomization, using time asymptotics of the Lagrange multipliers involved in the maximum entropy model construction. Thus for the first time a complete unification of deterministic and randomized uncertainty models is achieved. Various interpretations, consequences and applications of this unification are explained and discussed.},
	address = {San Diego, CA},
	booktitle = {45th IEEE Conference on Decision and Control},
	pages = {pp. 4899-4906}
}
@conference {
	title = {Gibbs Sampler Based Control of Autonomous Vehicle Swarms in the Presence of Sensor Errors},
	author = {Xi, Wei., Baras, John S.},
	year = {2006},
	month = {12/2006},
	abstract = {In earlier work of the authors[1], [2], [3], [4], [5], it was shown that Gibbs sampler based annealing algorithms could be used for vehicle swarms to achieve self-organization. Nevertheless, the earlier convergence analyses were based on the assumption that the Gibbs potential can be precisely evaluated. In practice, Gibbs potentials have to be measured via sensors, which usually introduce errors. The robustness of the stochastic algorithm under sensor errors is studied in this paper. Two types of sensor error, range-error and random error, are investigated. Analytical results on convergence are derived for sensor errors with limited support, and are further validated through simulations.},
	address = {San Diego, CA},
	booktitle = {45th IEEE Conference on Decision and Control},
	pages = {pp. 5084-5090}
}
@conference {
	title = {Multiple Sampling for Estimation on a Finite Horizon},
	author = {Rabi, Maben., Moustakides, George V., Baras, John S.},
	year = {2006},
	month = {12/2006},
	abstract = {We discuss some multiple sampling problems that arise in finite horizon real-time estimation when there is an upper limit on the number of allowable samples. Measuring estimation quality by the aggregate squared error, we compare the performances of the best deterministic, level-triggered and the optimal sampling schemes. We restrict the signal to be either a Wiener or an Ornstein-Uhlenbeck process. For the Wiener process, we provide closed form expressions and series expansions, whereas for the Ornstein Uhlenbeck process, procedures for numerical computation. Our results indicate that the best level-triggered sampling is almost optimal when the signal is stable.},
	address = {San Diego, CA},
	booktitle = {45th IEEE Conference on Decision and Control},
	pages = {pp. 1351-1357}
}
@conference {
	title = {Coalition Formation in MANETS},
	author = {Jiang, Tao., Theodorakopoulos, George., Baras, John S.},
	year = {2006},
	month = {11/2006},
	abstract = {Wireless ad-hoc networks rely on the cooperation of participating nodes for almost all their functions. However, due to resource constraints, nodes are generally selfish and try to maximize their own benefit when participating in the network. Therefore, it is important to study mechanisms which can be used as incentives to form coalitions inside the network. In this paper, we study coalition formation based on game theory, especially cooperative game theory. First, the dynamics of coalition formation proceeds via pairwise bargaining. We show that the size of the maximum coalition is a decreasing function of the cost for establishing a link. After the coalition formation process reaches the steady state, we are interested in the stability of coalitions. We prove that coalitions are stable in terms of both pairwise stability and coalitional stability.},
	address = {Orlando, FL},
	booktitle = {25th Army Science Conference},
	pages = {pp.1-8}
}
@conference {
	title = {A Unified Framework of Information Assurance for the Design and Analysis fo Security Algorithms},
	author = {Cardenas, Alvaro A., Taban, Gelareh., Baras, John S.},
	year = {2006},
	month = {11/2006},
	abstract = {Most information security algorithms cannot achieve perfect security without incurring severe operational costs such as false alarms, network congestion, capital investment etc. Operating or designing an algorithm with perfect security is therefore not an economically rational alternative and thus the question arises of how to find the appropriate tradeoff between security and its costs. Although several other researchers have recognized that there is a tradeoff, there is very little work in formally characterizing it. This paper provides the first steps towards a more systematic and general approach for cost-effective security management.},
	address = {Orlando, FL},
	booktitle = {25th Army Science Conference},
	pages = {pp. 1-8}
}
@conference {
	title = {Component Based Routing: A New Methodology for Designing Routing Protocols for MANET},
	author = {Huang, H., Baras, John S.},
	year = {2006},
	month = {11/2006},
	abstract = {Large variation of performance due to various environment inputs is a major impediment of implementing existing routing protocols for MANET in the battlefield. Therefore, it is a major challenge to design a routing protocol that can adapt its behavior to environment alteration. In consideration of adaptability to the environment and flexibility in protocol construction, a novel component based routing protocol methodology is proposed in this paper. Distinguished from conventional investigation of routing protocols as individual entities, this paper will firstly generalize four fundamental components for MANET routing protocols. Then, a weak component diagnosis process is proposed to improve a weak component and enhance the overall performance. Finally, preliminary simulation results demonstrate the power of the component based methodology for improving overall performance and reducing performance variation. In conclusion, the evaluation and improvement at the component level is more insightful and effective than that at the protocol level.},
	address = {Orlando, FL},
	booktitle = {25th Army Science Conference},
	pages = {pp. 1-8}
}
@conference {
	title = {A Game for Ad Hoc Network Connectivity in the Presence of Malicious Users},
	author = {Theodorakopoulos, George., Baras, John S.},
	year = {2006},
	month = {11/2006},
	abstract = {Ad hoc network users are resource constrained: Before transmitting data, they have to take into account the energy expenditure involved. Even if a user is, in principle, willing to spend energy to improve network connectivity, his actual decision will be heavily influenced by the decisions of his neighboring users, since they act as relay nodes for him. Moreover, some of the neighbors may not be as benign as he is; in fact, they could be outright malicious. We are abstracting the tradeoff between spending energy and increasing connectivity by modeling the interaction of a user with his one-hop neighbors in a game theoretic fashion. Two types of users exist: Good users willingly trade energy for connectivity, but only if they expect their neighbors to do the same; Bad users try to destroy connectivity, but also lure the Good users to waste energy. Within our model for user behavior and sophistication, we explore outcomes that can arise in this graphical game.},
	address = {San Francisco, CA},
	booktitle = {2006 IEEE Globecom Technical Conference},
	pages = {pp. 1-5}
}
@conference {
	title = {Energy Efficient Millimeter Wave Radio Link Establishment for Low Probability of Intercept with Smart Antenna Arrays},
	author = {Neekzad, Behnam., Baras, John S., Sayrafian, Kamran.},
	year = {2006},
	month = {11/2006},
	abstract = {Consider a system of two millimeter wave transceiver nodes A and B. We assume that each node is equipped with a circular array antenna that has beamforming capability. We are interested in using the beamforming capability to find the best possible directions for transmission and reception such that the communication link between two nodes provides maximal SNR at the receiver. A protocol that in most cases achieves the optimal solution is developed and simulation results are provided to show the effectiveness of the algorithm.},
	address = {Orlando, FL},
	booktitle = {25th Army Science Conference},
	pages = {pp. 1-6}
}
@conference {
	title = {A Testbed for Comparing Trust Computation Algorithms},
	author = {Theodorakopoulos, George., Baras, John S.},
	year = {2006},
	month = {11/2006},
	abstract = {Trust is the expectation of a person about another person{\textquoteright}s behavior. Trust is important for many security related decisions about, e.g., granting or revoking privileges, controlling access to sensitive resources and information, or evaluating intelligence gathered from multiple sources. More often than not, the issue is complicated even further because the person making the decision has no direct trust relationship with every single subject whose trustworthiness needs to be evaluated. So, the decision maker needs to rely on recommendations by others, and then somehow aggregate the trust related information that is collected. In this work we provide an algebraic framework in which we can describe multiple ways that trust related information can be aggregated to form a single value. We show the similarities and differences that the various so called trust computation algorithms have, and associate these with the algebraic properties of the frame- work that we consider.},
	address = {Orlando, FL},
	booktitle = {25th Army Science Conference},
	pages = {pp. 1-8}
}
@conference {
	title = {Two-Level Dynamic Bandwidth Allocation for A Space-To-Ground Relay Network},
	author = {Zeng, Hui., Hadjitheodosiou, Michael., Baras, John S.},
	year = {2006},
	month = {11/2006},
	abstract = {We address issues related to efficiency, fairness, end to- end delay minimization and Quality-of-Service in order to enable a flexible access and dynamic mission operation capability in the next generation NASA space-to-ground communication infrastructure. To provide efficient and fair utilization while guaranteeing specific service requirements for different traffic classes, we propose a two-level (long-term and short-term) sharing of a slotted high data rate satellite communication link. The implemented long-term optimal bandwidth allocation provides per-user/per-flow service guarantee and gives the inputs to the next level. In our short-term bandwidth allocation with threshold regulation, a small portion of bandwidth is still assigned to all active spacecraft in advance, but most bandwidth is dynamically allocated per frame by solving an optimal timeslot scheduling problem. We finally discuss simulation results and our design optimization approach.},
	address = {San Francisco, CA},
	booktitle = {2006 IEEE Globecom Technical Conference},
	pages = {pp. 1-6}
}
@conference {
	title = {Detection and Performance Analysis of Greedy Individual and Colluding MAC Layer Attackers},
	author = {Radosavac, Svetlana., Baras, John S.},
	year = {2006},
	month = {11/2006},
	abstract = {Selfish behavior at the Medium Access (MAC) Layer can have devastating side effects on the performance of wireless networks, with effects similar to those of Denial of Service (DoS) attacks. In this paper we consider the problem of misbehavior detection at the MAC layer, focusing on the back-off manipulation by colluding selfish nodes. We cast the problem within a minimax robust detection framework, providing a detection rule of optimum performance for the worst-case attack. We analyze the effects of a single optimal attacker with respect to the detection delay and average number of backoff slots and compare them with the effects of colluding attackers.},
	address = {Myconos, Greece},
	booktitle = {2006 Information Society Technologies Conference}
}
@conference {
	title = {Distributed Trust in MANET: New Analytical Approaches},
	author = {Baras, John S.},
	year = {2006},
	month = {11/2006},
	address = {Adelphi, Maryland},
	booktitle = {Collaborative Technology Alliance on Communications and Networks},
	organization = {Army Research Laboratory}
}
@conference {
	title = {Impact of Optimal MAC Layer Attacks on the Network Layer},
	author = {Radosavac, Svetlana., Baras, John S., Moustakides, George V.},
	year = {2006},
	month = {10/2006},
	abstract = {Node misbehavior in wireless ad hoc networks leads to sudden unpredictable changes in network topology, resulting in fluctuation of traffic load and capacity for already existing links. In this work we consider node misbehavior in the Medium Access Control (MAC) layer and its effects on the performance of the network layer. In order to capture uncertainty of the attacker{\textquoteright}s strategy as well as the unpredictable nature of the wireless medium, we quantify the optimal attack strategy by using the principle of minimum cross entropy. Following that, we apply the obtained results for analysis of the IEEE 802.11 DCF MAC protocol and investigate the effects of such optimal attacks on the network layer. Finally, we evaluate the robustness of two different routing protocols against the worst-case MAC layer attacks and justify the need for the MAC layer-based Intrusion Detection Systems (IDS).},
	address = {Alexendria, VA},
	booktitle = {Fourth ACM Workshop on Security of Ad Hoc and Sensor Networks (SASN 2006)},
	pages = {pp. 135-145}
}
@conference {
	title = {Autonomic Wireless Networks and Computational Problems on Graphs},
	author = {Baras, John S.},
	year = {2006},
	month = {10/2006},
	address = {Stockholm, Sweden},
	organization = {Center for Industrial and Applied Mathematics, Royal Institute of Technology (CIAM KTH)}
}
@conference {
	title = {Analytical Methods for Trust Management in Autonomic Networks},
	author = {Baras, John S.},
	year = {2006},
	month = {10/2006},
	address = {Leuven, Belgium},
	booktitle = {Study Day of the Interuniversity Attraction Pole IAP V/22 Dynamical Systems and Control: Computation, Identification and Modelling, the UCL research action on Large Graphs and Networks and the Francqui Foundation},
	organization = {Katholieke Universiteit Leuven}
}
@conference {
	title = {Component Based Design and Synthesis of Cyber-Physical Systems},
	author = {Baras, John S.},
	year = {2006},
	month = {10/2006},
	address = {Austin, Texas},
	booktitle = {NSF Workshop on Cyber-Physical Systems}
}
@conference {
	title = {Incentive Compatible Medium Access Control in Wireless Networks},
	author = {Benammar, Nassir., Baras, John S.},
	year = {2006},
	month = {10/2006},
	abstract = {The current IEEE 802.11 medium access control standard is being deployed in coffee shops, in airports and even across major cities. The terminals accessing these wi-fi access points do not belong to the same entity, as in corporate networks,but are usually individually owned and operated. Entities sharing these network resources have no incentive in following protocol rules other than to optimize their overall utility, usually a function of throughput and delay. We briefly discuss shortfalls of the current IEEE 802.11 standard in environments where terminals are competing for a common bandwidth resource, and then we introduce a new MAC protocol designed with the above considerations. Thus the new Incentive Compatible MAC (ICMAC) protocol is more suited for these open environments, without compromising the overall network performance.},
	address = {Pisa, Italy},
	booktitle = {2006 Workshop on Game Theory for Networks (GameNets 2006)}
}
@conference {
	title = {Systems Engineering for Automating V\&V of Dependable Systems},
	author = {Baras, John S.},
	year = {2006},
	month = {10/2006},
	address = {Alexendria, VA},
	booktitle = {NITRD HCSS-AS National Workshop on Aviation Software Systems: Design for Certifiably Dependable Systems}
}
@conference {
	title = {Dynamic Path Planning Around Moving Obstacles by Collaborating Robots for Space Exploration},
	author = {Brezina, Matthew, Baras, John S.},
	year = {2006},
	month = {09/2006},
	abstract = {We investigate dynamic control of collaborating robots by integrating methodologies from path planning and dynamic prediction of moving obstacles. Predicting for a finite horizon, instead of one step ahead, provides far better results. Efficient distributed algorithms are implemented and demonstrated via simulations. A combination of optimization and logic is needed for best performance and efficiency.},
	address = {San Jose, CA},
	booktitle = {Space 2006},
	pages = {pp. 1-5}
}
@conference {
	title = {An Integrative Principled Approach to Network Science for Autonomic Networks},
	author = {Baras, John S.},
	year = {2006},
	month = {08/2006},
	address = {Athens, Greece},
	booktitle = {ARO-AFOSR Network Science Workshop}
}
@conference {
	title = {An Integrative Principled Approach to Network Science for Autonomic Networks},
	author = {Baras, John S.},
	year = {2006},
	month = {08/2006},
	address = {Athens, Greece},
	booktitle = {ARO-AFOSR Network Science Workshop}
}
@conference {
	title = {Emerging Wireless Technologies and Services for Better Quality of Life and Work},
	author = {Baras, John S.},
	year = {2006},
	month = {08/2006},
	address = {Athens, Greece},
	booktitle = {45th Congress of the Federation of Telecommunications Engineers of the European Community (FITCE)}
}
@conference {
	title = {Enhancing Benign User Cooperation in the Presence of Malicious Adversaries in Ad Hoc Networks},
	author = {Theodorakopoulos, George., Baras, John S.},
	year = {2006},
	month = {08/2006},
	abstract = {Decentralized and unstructured networks are becoming more prevalent today (e.g. ad hoc networks). Like every network, they depend on the cooperation of their users to survive. However, each user does not necessarily know who the others are, or what their intentions are. Since there is no centralized infrastructure, the users can only base their decision on what they observe themselves. Ideally, they would like to cooperate only with users that have common interests with them. In this paper, we use a game theoretic model for the above situation. We assume there are only two kinds of users, Good (benign) and Bad (malicious). Good users receive a high game theoretic payoff when they cooperate with other Good users, but a low payoff when they cooperate with Bad users. We propose behavior rules (strategies) to achieve equilibria that enable as many Good users as possible to cooperate with each other, and at the same time minimize the number of Good-Bad cooperations.},
	address = {Baltimore, MD},
	booktitle = {2006 IEEE Communications Society/CreateNet International Conference on Security and Privacy in Communication Networks}
}
@conference {
	title = {Broadband Mobile Wireless Infrastructures: The Next {\textquoteleft}Massive Impact{\textquoteright} Paradigm Shift},
	author = {Baras, John S.},
	year = {2006},
	month = {07/2006},
	address = {Tokyo, Japan},
	organization = {Fujitsu Laboratories, Kawasaki}
}
@conference {
	title = {Vehicle Wireless Networks},
	author = {Baras, John S.},
	year = {2006},
	month = {07/2006},
	address = {Tochigi, Japan},
	organization = {HONDA R\&D Center}
}
@conference {
	title = {Scalable and Distributed Control Laws for Network flow Optimization},
	author = {Chen, Huigang., Baras, John S.},
	year = {2006},
	month = {07/2006},
	abstract = {We investigate the design of scalable and distributed control laws for flow control in a large network - equivalently an optimization problem. We identify the implications of the desired "plug-and-play{\textquoteright} property of of such protocols and propose design principles upon which our algorithm should be built: the class of our algorithms must achieve little extra communication cost and global asymptotic stability. General structural properties of such algorithms are presented and we finally provide an algorithm which satisfies our design principles for a network with heterogeneous delays.},
	address = {Kyoto, Japan},
	booktitle = {17th International Symposium on Mathematical Networks and Systems},
	pages = {pp. 42-49}
}
@conference {
	title = {Linear Iterations on Ordered Semirings for Trust Metric Computation and Attack Resiliency Evaluation},
	author = {Theodorakopoulos, George., Baras, John S.},
	year = {2006},
	month = {07/2006},
	abstract = {Within the realm of network security, we interpret the concept of trust as a relation among entities that participate in various protocols. Trust relations are based on evidence created by the previous interactions of entities within a protocol. In this work, we are focusing on the evaluation of trust evidence in Ad Hoc Networks. Because of the dynamic nature of Ad Hoc Networks. Because of the dynamic nature of Ad Hoc Networks, trust evidence may be uncertain and incomplete. Also, no pre-established infrastructure can be assumed. The evaluation process is modelled as a path problem on a directed graph, where nodes represent entities, and edges represent trust relations. We develop a novel formation of trust computation as linear interactions on ordered semirings. Using the theory of semirings, we analyze several key problems on the performance of trust algorithms. We also analyze the resilience to attacks of the resulting schemes.},
	address = {Kyoto, Japan},
	booktitle = {Proceedings of the 17th International Symposium on Mathematical Networks and Systems},
	pages = {pp. 509-514}
}
@conference {
	title = {B-ROC Curves for the Assessment of Classifiers over Imbalanced Data Sets},
	author = {Cardenas, Alvaro A., Baras, John S.},
	year = {2006},
	month = {07/2006},
	abstract = {The class imbalance problem appears to be ubiquitous to a large portion of the machine learning and data mining communities. One of the key questions in this setting is how to evaluate the learning algorithms in the case of class imbalances. In this paper we introduce the Bayesian Receiver Operating Characteristic (B-ROC) curves, as a set of tradeoff curves that combine in an intuitive way, the variables that are more relevant to the evaluation of classifiers over imbalanced data sets. This presentation is based on section 4 of (C{\textasciiacute}ardenas, Baras, \&amp; Seamon 2006).},
	address = {Boston, Massachusetts},
	booktitle = {21st National Conference on Artificial Intelligence, (AAAI 06) Nectar track,},
	pages = {pp. 1581-1584}
}
@conference {
	title = {Evaluation of Classifiers Practical Considerations for Security Applications},
	author = {Cardenas, Alvaro A., Baras, John S.},
	year = {2006},
	month = {07/2006},
	abstract = {In recent years several tools based on statistical methods and machine learning have been incorporated in security related tasks involving classification, such as intrusion detection systems (IDSs), fraud detection, spam filters, biometrics and multimedia forensics. Measuring the security performance of these classifiers is an essential part for facilitating decision making, determining the viability of the product, or for comparing multiple classifiers. There are however relevant considerations for security related problems that are sometimes ignored by traditional evaluation schemes. In this paper we identify two pervasive problems in securityrelated applications. The first problem is the usually large class imbalance between normal events and attack events. This problem has been addressed by evaluating classifiers based on cost-sensitive metrics and with the introduction of Bayesian Receiver Operating Characteristic (B-ROC) curves. The second problem to consider is the fact that the classifier or learning rule will be deployed in an adversarial environment. This implies that good performance on average might not be a good performance measure, but rather we look for good performance under the worst type of adversarial attacks. In order to address this notion more precisely we provide a framework to model an adversary and define security notions based on evaluation metrics},
	address = {Boston, MA},
	booktitle = {AAAI Workshop on Evaluation Methods for Machine Learning}
}
@conference {
	title = {Evaluation of Classifiers: Practical Considerations for Security Applications},
	author = {Cardenas, Alvaro A., Baras, John S.},
	year = {2006},
	month = {07/2006},
	abstract = {In recent years several tools based on statistical methods and machine learning have been incorporated in security related tasks involving classification, such as intrusion detection systems (IDSs), fraud detection, spam filters, biometrics and multimedia forensics. Measuring the security performance of these classifiers is an essential part for facilitating decision making, determining the viability of the product, or for comparing multiple classifiers. There are however relevant considerations for security related problems that are sometimes ignored by traditional evaluation schemes. In this paper we identify two pervasive problems in security related applications. The first problem is the usually large class imbalance between normal events and attack events. This problem has been addressed by evaluating classifiers based on cost-sensitive metrics and with the introduction of Bayesian Receiver Operating Characteristic (B-ROC) curves. The second problem to consider is the fact that the classifier or learning rule will be deployed in an adversarial environment. This implies that good performance on average might not be a good performance measure, but rather we look for good performance under the worst type of adversarial attacks. In order to address this notion more precisely we provide a framework to model an adversary and define security notions based on evaluation metrics.},
	address = {Boston, Massachusetts},
	booktitle = {AAAI Workshop on Evaluation Methods for Machine Learning}
}
@conference {
	title = {Modeling and Synthesis of Networked Systems},
	author = {Baras, John S.},
	year = {2006},
	month = {07/2006},
	address = {Paris, France},
	booktitle = {Joint CTS-HYCON Workshop on Nonlinear Research and Hybrid Control}
}
@conference {
	title = {Ray-Tracing Simulation of the NICT Channel Measurements},
	author = {Sayrafian, Kamran., Neekzad, Behnam., Perez, Julio., Baras, John S.},
	year = {2006},
	month = {07/2006},
	address = {San Diego, CA},
	booktitle = {IEEE Standard 802.15.3c mm-Wave channel modeling subgroup}
}
@conference {
	title = {Modeling Key Agreement in Multi-Hop Ad Hoc Networks},
	author = {Crescenzo, Giovanni Di., Striki, Maria., Baras, John S.},
	year = {2006},
	month = {07/2006},
	abstract = {Securing multicast communications in ad hoc networks has become one of the most challenging research directions in the areas of wireless networking and security. This is especially true as ad hoc networks are emerging as the desired environment for an increasing number of civilian, commercial and military applications, also addressing an increasingly large number of users. In this paper we study a very basic security question for Ad Hoc Networks: Key Agreement against passive adversaries. Despite being a widely studied area in wired networks, the problem becomes significantly more challenging for ad hoc networks, and even more for sensor networks, due to lack of trusted entities, infrastructures, full connectivity, routing structures, and due to severe limitations on the resources and capabilities of network nodes. In this paper we perform a comprehensive investigation of Key Agreement over resource constrained ad hoc networks. First, we formally model the key agreement problem over multi-hop ad hop networks, and we directly extend known key agreement protocols for wired networks, and evaluate the efficiency of such approaches. We then go beyond natural extensions of such protocols, by proposing non-trivial extensions based on efficient topology-driven simulations of logical networks over an arbitrary physical network, in order to optimize the most significant metrics of interest for such networks: i.e. bandwidth, latency, processing cost. Indeed, the resulting protocols are significantly more efficient in some or all of the above metrics, as our analytical results indicate},
	address = {Vancouver, Canada},
	booktitle = {2006 International Wireless Communications and Mobile Computing Conference},
	pages = {pp. 39-44}
}
@conference {
	title = {Distributed Control of Autonomous Swarms by Using Parallel Simulated Annealing Algorithm},
	author = {Xi, Wei., Baras, John S.},
	year = {2006},
	month = {06/2006},
	abstract = {In early work of the authors, it was shown that Gibbs sampler based sequential annealing algorithm could be used to achieve self-organization in swarm vehicles based only on local information. However, long travelling time presents barriers to implement the algorithm in practice. In this paper we study a popular acceleration approach, the parallel annealing algorithm, and its convergence properties. We first study the convergence and equilibrium properties of the synchronous parallel sampling algorithm. A special example based on a battle field scenario is then studied. Sufficient conditions that the synchronous algorithm leads to desired configurations (global minimizers) are derived. While the synchronized algorithm reduces travelling time, it also raises delay and communication cost dramatically, in order to synchronize moves of a large group of vehicles. An asynchronous version of the parallel sampling algorithm is then proposed to solve the problem. Convergence properties of the asynchronous algorithm are also investigated.},
	address = {Anconia, Italy},
	booktitle = {14th Mediterranean Conference on Control and Automation},
	pages = {pp. 1-6}
}
@conference {
	title = {Efficient Sampling for Keeping Track of an Ornstein-Uhlenbeck Process},
	author = {Rabi, Maben., Moustakides, George V., Baras, John S.},
	year = {2006},
	month = {06/2006},
	abstract = {We consider estimation and tracking problems in sensor networks with constraints in the hierarchy of inference making, on the sharing of data and inter-sensor communications. We identify as a typical representative for such problems tracking of a process when the number and type of measurements are constrained. As the simplest representative of such problems, which still encompasses all the key issues involved, we analyze efficient sampling schemes for tracking an Ornstein- Uhlenbeck process. We consider sampling based on time, based on amplitude (event-triggered sampling) and optimal sampling (optimal stopping). We obtain the best sampling rule in each case as the solution to a constrained optimization problem. We compare the performances of the various sampling schemes and show that the event-triggered sampling performs close to optimal. Implications and extensions are discussed.},
	address = {Anconia, Italy},
	booktitle = {14th Mediterranean Conference on Control and Automation},
	pages = {pp. 1-6}
}
@conference {
	title = {Control and Security of Networked Embedded Systems: Component Based Synthesis},
	author = {Baras, John S.},
	year = {2006},
	month = {06/2006},
	address = {Helsinki, Finland},
	booktitle = {, NSF-EU/IST TEKES Workshop: Long Term Challenges in High Confidence Embedded Systems}
}
@conference {
	title = {Distributed Trust Management in Wireless Autonomic Networks},
	author = {Baras, John S.},
	year = {2006},
	month = {06/2006},
	address = {Canberra, Australia},
	organization = {Research School of Information Sciences and Engineering (RSISE), Australian National University}
}
@conference {
	title = {Flexible and Dynamic Communication Architecture for Lunar Exploration},
	author = {Zeng, Hui., Roy-Chowdhury, Ayan., Rentz, Nicolas., Hadjitheodosiou, Michael., Baras, John S.},
	year = {2006},
	month = {06/2006},
	abstract = {We present work related to designing a communication network for lunar exploration. We discuss the important requirements for future space missions that influence the design of this network. We list some characteristics of the network, and highlight important issues and constraint related to performance, cost, and future network evolution. We address issues related to efficiency, fairness, end-to-end delay minimization and Quality-of-Service (QoS) framework in order to enable a flexible access and dynamic mission operation. To provide optimal or near-optimal efficient utilization and fair allocation of bandwidth of the downlink channel while guaranteeing specific QoS requirements for different service classes, we propose two-level (long-term static and short-term dynamic) sharing of a slotted high data rate satellite communication link. The long-term optimal bandwidth allocation is implemented to provide per-stream/per-user QoS guarantee and give the inputs to the next level, short-term dynamic bandwidth allocation. In our time-varying short-term bandwidth allocation with threshold regulation, a small portion of bandwidth is still assigned to all active spacecrafts in advance, but most bandwidth is dynamically allocated by the requests from them, per frame, by solving an optimal timeslot scheduling problem.},
	address = {San Diego, CA},
	booktitle = {24th American Institute of Aeronautics and Astronautics},
	pages = {pp. 1-9}
}
@conference {
	title = {Flow Control and Active Queue Management for Integrated Services in an Aeronautical Satellite Network},
	author = {Shang, Yadong., Hadjitheodosiou, Michael., Baras, John S.},
	year = {2006},
	month = {06/2006},
	abstract = {The IP-based broadband aeronautical satellite network will provide numerous new applications and services for both airspace system operations and passenger communications. Application of commercial off the shelf technologies and techniques has the potential to make network operations economically and technically realizable. However the performance of data communication protocols and applications over aeronautical satellite networks is degraded dramatically. For the satellite channel, the window based flow control algorithm may cause transient congestion. The flow control mechanisms with or without explicit feedback from the congested resource are limited in performance and not effective. We propose a hierarchical scheduler for satellite gateways. Different service disciplines are used for integrated services. A Random Early Detection Flow Control (REDFC) algorithm is proposed for best-effort traffic at the satellite gateways. In REDFC, each packet is transmitted with a probability that is a function of the queue length. If the packet is not transmitted successfully, it will be retransmitted after certain time interval. We also propose a virtual parallel queue structure as a new active queue management scheme for short life and long life web traffic. The new flow control and active queue management schemes will provide better performance for integrated services in aeronautical satellite networks.},
	address = {San Diego, CA},
	booktitle = {24th American Institute of Aeronautics and Astronautics},
	pages = {pp. 1-10}
}
@conference {
	title = {A Robust Distributed TGDH-based Scheme for Secure Group Communications in MANET{\textquoteright}s},
	author = {Striki, Maria., Baras, John S., Manousakis, Kyriakos.},
	year = {2006},
	month = {06/2006},
	abstract = {Securing multicast communications in Mobile Ad Hoc Networks (MANET) is considered among the most challenging research directions in the areas of wireless networking and security. MANET is emerging as the desired environment for an increasing number of commercial and military applications, addressing also a growing number of users. Security, on the other hand, is now an indispensable requirement for these applications. However, the limitations of the dynamic, infrastructure-less nature of MANET impose major difficulties in establishing a secure framework suitable for such services. The design of efficient key management (KM) schemes for MANET is of paramount importance since the performance of the KM functions imposes an upper limit on the efficiency and scalability of the whole secure group communication system. In this work, we contribute towards this direction by extending TGDH to a novel distributed scheme: DS-TGDH. Our aim is to modify TGDH to: a) be feasible in the most general resource-constrained MANET where no nodes with special capabilities exist, b) produce considerably lower overhead for the network nodes involved, c) handle disruptions with low cost. We consider the underlying routing protocol in our design, and we apply a distributed TGDH version over a robust schedule, optimizing parameters of interest. We focus on the design and analysis of the {\textquotedblleft}stealthy{\textquotedblright} TGDH and compare it with the original. Through our analysis and results, we shed insight on the actual feasibility of these protocols for MANET and provide realistic and fair comparison results that more accurately advocate the pros and cons of each protocol over the environment of study.},
	address = {Istanbul, Turkey},
	booktitle = {ICC2006 - IEEE International Conference on Communications},
	pages = {pp. 2249-2255}
}
@conference {
	title = {Future of Mobile Communications: Distributed Trust Management in Wireless Autonomic Networks},
	author = {Baras, John S.},
	year = {2006},
	month = {06/2006},
	address = {Mykonos, Greece},
	booktitle = {15th IST Mobile and Wireless Communication Research Summit}
}
@conference {
	title = {An Integrative Principled Approach to Network Science},
	author = {Baras, John S.},
	year = {2006},
	month = {05/2006},
	booktitle = {ARL Network Science STI Workshop}
}
@conference {
	title = {Consensus Problems on Small World Graphs: A Structural Study},
	author = {Hovareshti, Pedram., Baras, John S.},
	year = {2006},
	month = {05/2006},
	abstract = {Consensus problems arise in many instances of collaborative control of multi-agent complex systems; where it is important for the agents to act in coordination with the other agents. To reach coordination, agents need to share information. In large groups of agents the information sharing should be local in some sense, due to energy limitation, reliability, and other constraints. A consensus protocol is an iterative method that provides the group with a common coordination variable. However, local information exchange limits the speed of convergence of such protocols. Therefore, in order to achieve high convergence speed, we should be able to design appropriate network topologies. A reasonable conjecture is that the small world graphs should result in good convergence speed for consensus problems because their low average pairwise path length should speed the diffusion of information in the system. In this paper we address this conjecture by simulations and also by studying the spectral properties of a class of matrices corresponding to consensus problems on small world graphs.},
	address = {Boston, Massachusetts},
	booktitle = {2006 International Conference on Complex Systems},
	pages = {pp. 1-8}
}
@conference {
	title = {A Framework for the Evaluation of Intrusion Detection Systems},
	author = {Cardenas, Alvaro A., Baras, John S., Seamon, Karl.},
	year = {2006},
	month = {05/2006},
	abstract = {Classification accuracy in intrusion detection systems (IDSs) deals with such fundamental problems as how to compare two or more IDSs, how to evaluate the performance of an IDS, and how to determine the best configuration of the IDS. In an effort to analyze and solve these related problems, evaluation metrics such as the Bayesian detection rate, the expected cost, the sensitivity and the intrusion detection capability have been introduced. In this paper, we study the advantages and disadvantages of each of these performance metrics and analyze them in a unified framework. Additionally, we introduce the intrusion detection operating characteristic (IDOC) curves as a new IDS performance tradeoff which combines in an intuitive way the variables that are more relevant to the intrusion detection evaluation problem. We also introduce a formal framework for reasoning about the performance of an IDS and the proposed metrics against adaptive adversaries. We provide simulations and experimental results to illustrate the benefits of the proposed framework.},
	address = {Oakland, California},
	booktitle = {2006 IEEE Symposium on Security and Privacy}
}
@conference {
	title = {Networked Embedded Systems: Component Based System Synthesis},
	author = {Baras, John S.},
	year = {2006},
	month = {05/2006},
	booktitle = {Office of the Secretary of Defense (OSD) Software-Intensive Systems Producibility Workshop}
}
@conference {
	title = {Dynamic Bandwidth Allocation for a Space Relay Communications Network},
	author = {Zeng, Hui., Hadjitheodosiou, Michael., Baras, John S.},
	year = {2006},
	month = {04/2006},
	abstract = {We address issues related to efficiency, fairness, end-to-end delay minimization and Quality-of-Service framework in order to enable a flexible access and dynamic mission operation capability in the next generation NASA space-to-ground communication infrastructure. To provide optimal or near-optimal efficient utilization and fair allocation of bandwidth of the downlink channel while guaranteeing specific service requirements for different service classes, we propose two-level (long-term static and short-term dynamic) sharing of a slotted high data rate satellite communication link. The long-term optimal bandwidth allocation is implemented to provide per-stream/per-user service guarantee and give the inputs to the next level short-term dynamic bandwidth allocation. In our time-varying short-term bandwidth allocation with threshold regulation, a small portion of bandwidth is still assigned to all active spacecraft in advance but most bandwidth is dynamically allocated by the requests from them per frame by solving an optimal time slot scheduling problem.},
	address = {Charlottesville, Virginia},
	booktitle = {2006 IEEE Systems and Information Engineering Design Symposium (SIEDS06)},
	pages = {pp.75-80}
}
@conference {
	title = {Analyzing BGP ASPATH Behavior in the Internet},
	author = {Blazakis, Dionysus., Karir, Manish., Baras, John S.},
	year = {2006},
	month = {04/2006},
	abstract = {In this paper we introduce a new metric for analyzing the behaviour of ASPATH values in the Border Gateway Protocol (BGP) routing protocol. We base our metric on the edit distance algorithm, an algorithm used for approximate string matching. We modify this basic algorithm by adding features that embed BGP domain knowledge. This allows us to perform meaningful comparisons of ASPATH values contained in BGP update messages. We call our modified metric ASPATH Edit Distance(AED). We illustrate the application of this metric to characterize ASPATH changes at a global scale using the example of a major Internet routing anomaly. At the other end of the spectrum we illustrate how this metric can be used to quantify and model the behaviour of ASPATH values for individual Autonomous Systems. AED provides us with an important measure with which we can study the behaviour of ASPATHS in the Internet. With sufficient refinement, AED can be suitably adapted and used alongside other metrics in BGP routing anomaly detection algorithms and tools.},
	address = {Barcelona, Spain},
	booktitle = {Proceedings of the 9th IEEE Global Internet 2006 Symposium}
}
@conference {
	title = {Trust Evaluation in Anarchy: A Case Study on Autonomous Networks},
	author = {Jiang, Tao., Baras, John S.},
	year = {2006},
	month = {04/2006},
	abstract = {With the explosive growth of network techniques, in particular wireless communications, the traditional centralized, fixed networks can no longer satisfy the enormous demands on network connectivity, data storage and information exchanges. New types of networks, such as pervasive computing networks, mobile ad hoc networks and P2P networks, emerged in recent years in order to provide solutions for the increasing requirements on networked services. All those networks are autonomous networks, because they are distributed and self-organized. As a case study, we employ a specific application {\textendash} distributed trust management {\textendash} to understand and analyze the behavior and properties of these {\textquotedblleft}anarchical{\textquotedblright} autonomous networks. We propose a statistical trust evaluation rule, prove its convergence and investigate its characteristics when the system is at the steady state. Our investigation results in several conclusions for the design of trust evaluation rules, some of which are unexpected if we do not have the stationary distribution at hand. Our study shows the importance and necessity of applying theoretical analyses to understand the complex characteristics of distributed, self-organized, autonomous networks.},
	address = {Barcelona, Spain},
	booktitle = {Proceedings of the 25th IEEE Conference on Computer Communications (Infocom06)}
}
@conference {
	title = {BGP-Inspect - Extracting Information from Raw BGP Data},
	author = {Blazakis, Dionysus., Karir, Manish., Baras, John S.},
	year = {2006},
	month = {04/2006},
	abstract = {While BGP routing datasets, consisting of raw routing data, are freely available and easy to obtain, extracting any useful information is tedious. Currently, researcher and network operators implement their own custom data processing tools and scripts. A single tool that provides easy access to the information within large raw BGP data-sets could be used by both communities to avoid re-writing these tools each time. Moreover, providing not just raw BGP messages, but some commonly used summary statistics as well can help guide deeper custom analyses. Based on these observations this paper describes the first steps towards building a scalable tool. We describe the various techniques and algorithms we have used to build an efficient generic tool called BGP-Inspect. When dealing with large datasets, dataset size, lookup speed, and data processing time are the most challenging issues. We describe our implementations of chunked compressed files and B+ tree indices that attempt to address these issues. We then provide an evaluation of our implementations. Finally, we provide some example scenarios and case studies where BGP-Inspect can provide useful insight into the management and operation of complex BGP based networks. An efficient and flexible back-end custom BGP message database, coupled with an intuitive and easy to use web-based query front-end makes BGP-Inspect a unique and powerful tool.},
	address = {Vancouver, Canada},
	booktitle = {10th IEEE/IFIP Network Operations and Management Symposium},
	pages = {pp.174-185}
}
@conference {
	title = {Networked Embedded Systems: Component Based Design and Security},
	author = {Baras, John S.},
	year = {2006},
	month = {03/2006},
	booktitle = {Joint US-EU Workshop: ICT Enabled Critical Infrastructures and Interdependencies}
}
@conference {
	title = {Collaborative Networked Control: Stochastic Algorithms},
	author = {Baras, John S.},
	year = {2006},
	month = {03/2006},
	address = {Champaign, IL},
	booktitle = {Decision and Control Seminar},
	organization = {University of Illinois Urbana-Champaign}
}
@conference {
	title = {Cooperative Games, Statistical Physics and Trust in Ad Hoc Networks},
	author = {Baras, John S.},
	year = {2006},
	month = {03/2006},
	address = {Champaign, IL},
	organization = {Information Trust Institute, University of Illinois Urbana-Champaign}
}
@conference {
	title = {On Trust Models and Trust Evaluation Metrics for Ad Hoc Networks},
	author = {Theodorakopoulos, George., Baras, John S.},
	year = {2006},
	month = {02/2006},
	abstract = {Within the realm of network security, we interpret the concept of trust as a relation among entities that participate in various protocols. Trust relations are based on evidence created by the previous interactions of entities within a protocol. In this work, we are focusing on the evaluation of trust evidence in ad hoc networks. Because of the dynamic nature of ad hoc networks, trust evidence may be uncertain and incomplete. Also, no preestablished infrastructure can be assumed. The evaluation process is modeled as a path problem on a directed graph, where nodes represent entities, and edges represent trust relations. We give intuitive requirements and discuss design issues for any trust evaluation algorithm. Using the theory of semirings, we show how two nodes can establish an indirect trust relation without previous direct interaction. We show that our semiring framework is flexible enough to express other trust models, most notably PGP{\textquoteright}s Web of Trust. Our scheme is shown to be robust in the presence of attackers.},
	booktitle = {IEEE Journal on Selected Areas in Communications},
	pages = {pp. 318-328}
}
@conference {
	title = {Collaborative Networked Control: Stochastic Algorithms},
	author = {Baras, John S.},
	year = {2006},
	month = {01/2006},
	address = {Athens, Greece},
	organization = {Institute of Communication and Computer Systems (ICCS), National Technical University of Athens}
}
@conference {
	title = {Collaborative Networked Control: Stochastic Algorithms},
	author = {Baras, John S.},
	year = {2006},
	month = {01/2006},
	address = {Vienna, Austria},
	organization = {Institute of Econometrics, Operations Research and Systems Theory, University of Technology Vienna}
}
@conference {
	title = {Trust in Self-organized Mobile Ad Hoc Networks},
	author = {Baras, John S.},
	year = {2006},
	month = {01/2006},
	address = {Lausanne, Switzerland},
	organization = {Center for Telecommunications Research, Ecole Federale Polytechnique de Lausanne (EPFL)}
}
@conference {
	title = {Coalition Formation in MANET and Other Networks},
	author = {Jiang, Tao., Theodorakopoulos, George., Baras, John S.},
	year = {2006},
	month = {01/2006},
	abstract = {Wireless ad-hoc networks rely on the cooperation of participating nodes for almost all their functions. However, due to resource constraints, nodes are generally selfish and try to maximize their own benefit when participating in the network. Therefore, it is important to study mechanisms which can be used as incentives to form coalitions inside the network. In this paper, we study coalition formation based on game theory, especially cooperative game theory. First, the dynamics of coalition formation proceeds via pairwise bargaining. We show that the size of the maximum coalition is a decreasing function of the cost for establishing a link. After the coalition formation process reaches the steady state, we are interested in the stability of coalitions. We prove that coalitions are stable in terms of both pairwise stability and coalitional stability.},
	address = {Orlando, FL},
	booktitle = {25th Army Science Conference}
}
