@conference {
	title = {Multi-scale Analysis of Long Range Dependent Traffic for Anomaly Detection in Wireless Sensor Networks},
	author = {Zheng, Shanshan., Baras, John S.},
	year = {2011},
	month = {12/2011},
	abstract = {Anomaly detection is important for the correct functioning of wireless sensor networks. Recent studies have shown that node mobility along with spatial correlation of the monitored phenomenon in sensor networks can lead to observation data that have long range dependency, which could significantly increase the difficulty of anomaly detection. In this paper, we develop an anomaly detection scheme based on multiscale analysis of the long range dependent traffic to address this challenge. In this proposed detection scheme, discrete wavelet transform is used to approximately de-correlate the traffic data and capture data characteristics in different time scales. The remaining dependencies are then captured by a multi-level hidden Markov model in the wavelet domain. To estimate the model parameters, we propose an online discounting Expectation Maximization (EM) algorithm, which also tracks variations of the estimated models over time. Network anomalies are detected as abrupt changes in the tracked model variation scores. We evaluate our detection scheme numerically using typical long range dependent time series.},
	address = {Orlando USA},
	booktitle = {50th IEEE Conference on Decision and Control and European Control Conference (CDC-ECC 2011)},
	pages = {pp. 4060-4065}
}
@conference {
	title = {Power Allocation Policy for Distributed Estimation in Wireless Networks},
	author = {Matei, Ion., Baras, John S.},
	year = {2011},
	month = {12/2011},
	abstract = {We consider a sensor network monitoring a stochastic process. The sensors exchange information over wireless communication channels affected by noise. The goal of the sensors is to compute accurate estimates of the state of the stochastic process under limited energy available for communications. We introduce a distributed algorithm which computes a power allocation scheme aimed at ensuring accurate state estimates and at saving communication energy. The distributed algorithm arise from solving an approximate convex optimization problem with constraints. We present how the power allocation scheme can be used for performing distributed estimation in the case where measurements are shared between sensors.},
	address = {Orlando, FL},
	booktitle = {50th IEEE Conference on Decision and Control Conference (CDC-ECC 2011)},
	pages = {pp. 7275-7280}
}
@conference {
	title = {Learning Behaviors for Coordination in Networked Systems and a Generalized Consensus Protocol},
	author = {Hovareshti, Pedram., Baras, John S.},
	year = {2011},
	month = {12/2011},
	abstract = {We consider the problem of coordination for efficient joint decision making in networks of autonomous agents. When making a decision, an agent is influenced by its knowledge about others{\textquoteright} behaviors. Agents{\textquoteright} understanding of others{\textquoteright} behaviors is shaped through observing their actions over a long time. We have modeled the decision making on whether to cooperate in a group effort as a result of a series of two-person games between agents, where the payoff of each agent is computed as the sum of its payoffs from each of these games. The agents initially have different behaviors. In order to maximize their pay-off, they need to learn the others{\textquoteright} behavior and coordinate with them. We consider a behavior learning algorithm for a class of behavior functions and study its effects on the emergence of coordination in the network. The conditions under which the learning algorithm converges are studied. We show that for a class of linear functions the learning algorithm results in an extension of non-homogeneous consensus protocol to the more general case of block-stochastic matrices.},
	address = {Orlando, Florida},
	booktitle = {50th IEEE Conference on Decision and Control and European Control Conference (CDC-ECC 2011)},
	pages = {pp. 2447-2452}
}
@conference {
	title = {Distributed Medium Access and Opportunistic Scheduling for Ad-Hoc Networks: An Analysis of the Constant Access Time Problem},
	author = {Chen, Hua., Hovareshti, Pedram., Baras, John S.},
	year = {2011},
	month = {12/2011},
	abstract = {In this paper, we study the problem of medium access and distributed opportunistic scheduling to exploit channel fluctuations for wireless ad-hoc networks. This work focuses on the Constant Access Time (CAT) problem, where the total time duration of channel probing and data transmission is slotted into fixed block length. In particular, we consider the dependence between channel rates at different time instances during the channel probing phase and its impact on the overall system throughput. We first analyze the system performance of the CAT problem under independent channel rate assumption and compare our result to the existing work on the Constant Data Time (CDT) problem. We then propose a protocol to reduce the channel probing costs based on this analysis. We show analytical results of the proposed protocol for systems with a sufficiently large number of users. We compare the system performance of the proposed protocol with that of the original protocol under independent channel rate assumption. We mathematically prove that the proposed protocol improves the system performance.},
	address = {Houston Texas},
	booktitle = {IEEE Globecom 2011},
	pages = {pp. 1-6}
}
@conference {
	title = {Thoughts Towards {\textquotedblleft}Science of Fingerprints},
	author = {Baras, John S.},
	year = {2011},
	month = {11/2011},
	address = {Salt Lake City, Utah},
	booktitle = {ARO Workshop on Fingerprinting}
}
@conference {
	title = {Factor Join Trees in Systems Exploration},
	author = {Yang, Shahan., Baras, John S.},
	year = {2011},
	month = {11/2011},
	abstract = {The interaction of connected components creates complexity impeding the analysis of large systems. Thorough exploration, appearing as formal verification, optimization or constraint satisfaction typically has a complexity that is either a high order polynomial or an exponential function of system size. However, for a large class of systems the essential complexity is linear in system size and exponential in treewidth which makes the previous notion of exponential complexity in system size an accidental overestimate.

In this paper, we demonstrate how this reduced complexity can be achieved using summary propagation on factor graphs. We describe summary propagation in terms of operations belonging to a commutative semiring-weighted relational algebra. We show how by appropriate selection of the commutative semiring, the same solution applies to propositional satisfiability, inference on Bayesian networks and a mixed integer linear optimization problem motivated by the power restoration problem for distributed, autonomous networks. This solution leads to a non-iterative distributed algorithm that operates on local data.

While weighted relational algebraic operators are used as the basic means of calculation, the algorithm presented works only on factor graphs that are trees. This requires the calculation of a non-unique structure called a join tree, which can be trivially generated from a unique structure called a cliqueseparator graph, which can be computed in linear time from a SysML Parametric Diagram description of the system for chordal systems1 . Interesting artifacts arise from this structural analysis which may be interpreted as interfaces and components. The framework also contains mathematical artifacts that may be interpreted as hierarchy and abstraction. We develop a tool to assist in the structural analysis described and implementations of the described algorithms.},
	address = {Paris, France},
	booktitle = {23rd International Conference on Software and Systems Engineering and their Applications (ICSSEA 2011)},
	pages = {pp. 1-12}
}
@conference {
	title = {Performance Evaluation of Single Channel Virtual-Circuit Medium Access Protocols for MANETs},
	author = {Perumal, Senni., Baras, John S.},
	year = {2011},
	month = {11/2011},
	abstract = {In this paper, we develop and evaluate models for estimating various performance metrics for unicast traffic using a single frequency channel virtual-circuit Medium Access Control (MAC) protocol in mobile wireless ad-hoc networks. Time is divided into periodic frames with a portion reserved for control traffic and the rest divided into timeslots for data traffic. In order to avoid interference between neighboring links, the virtualcircuit MAC protocol uses a set of reservation rules to assign timeslots to links. One such virtual-circuit MAC protocol is the hard scheduling mode of the reservation based Unifying Slot Assignment Protocol (USAP) with the number of frequency channels in a frame set to one. USAP uses a set of generic reservation rules to avoid interference between neighboring links. We model the performance of a single frequency channel virtualcircuit MAC protocol using reduced load loss network models that couple the physical, MAC, and routing layers effects. The blocking probability of a call at a particular link is calculated by considering cliques of neighboring interfering links that cannot transmit simultaneously. These neighboring interfering links and the conflict graph are calculated using the virtualcircuit reservation rules. We compare our results with simulation and show good match for large networks across various offered loads.},
	address = {Baltimore, Maryland},
	booktitle = {Milcom 2011},
	pages = {pp. 926-931},
	organization = {Baltimore Convention Center}
}
@conference {
	title = {Communication Network Challenges for Collaborative Vehicles},
	author = {Chen, Hua., Hovareshti, Pedram., Baras, John S.},
	year = {2011},
	month = {11/2011},
	abstract = {Networked systems of autonomous mobile agents have emerged in a variety of applications such as collaborative robotics, unmanned aerial/ground vehicles, mobile sensor networks and disaster relief operations. These agents utilize wireless communications for distributed computing, control and decision-making. Due to their limitations on energy supply, design and implementation of efficient distributed algorithms are crucial for these systems. This paper reviews different design aspects of networks of collaborative vehicles. We survey existing methods of addressing physical (PHY) and medium access control (MAC) layer, routing, and geometric connectivity issues for such networks and show limitations of these designs that address only single layer issues. We argue that a system engineering framework is needed for the design of such systems.},
	address = {Pacific Grove CA},
	booktitle = {Asilomar Conference on Signals, Systems, and Computers},
	pages = {pp. 1472-1476}
}
@conference {
	title = {A Model Based Platform for Design and Optimization of Multi-hop 802.11 Wireless Networks},
	author = {Baras, John S., Tabatabaee, Vahid., Jain, Kaustubh.},
	year = {2011},
	month = {10/2011},
	abstract = {We develop a loss model for multi-hop wireless networks based on IEEE 802.11 MAC. Given a multi-hop network topology, connection demands and routes, we model the working of 802.11 MAC in DCF mode to find good approximations to average MAC layer losses, service times and carried load. The model is defined as an implicit function amongst the variables in the model and solved using a fixed point approach. Further, using Automatic Differentiation (AD) on the implicit function , we perform sensitivity analysis and use it in an optimization framework. As an illustration of how this model can help in design and optimization of wireless networks, we optimize the network throughput by appropriate load splitting along multiple paths. We validate our models using network simulations.},
	address = {Miami Beach, Florida},
	booktitle = {8th ACM International Symposium on Performance Evaluation of Wireless Ad Hoc, Sensor and Ubiquitous Networks (PE-WANSUN 201},
	pages = {pp. 17-24}
}
@conference {
	title = {A Systems Biology Model Studying the Role of Cholesterol in Alzheimer{\textquoteright}s Disease Progression},
	author = {Kyrtsos, C Rose., Baras, John S.},
	year = {2011},
	month = {10/2011},
	abstract = {A simplified network describing the interactions between the cholesterol and beta amyloid (Aβ) synthesis pathways was generated using information available from literature and the KEGG database. A system of non-linear differential equations was developed and modeled using several different initial conditions. Rate constants were approximated using ratiometric data from the literature, or by fitting parameters to obtain a stable simulation within given biological constraints. Simulations demonstrated the importance of negative feedback control by cholesterol in the regulation of beta-amyloid levels. Additionally, the effect of reduced LRP-1 levels and oscillatory cholesterol generation was studied.},
	address = {Kos Island, Greece},
	booktitle = {10th IEEE International Workshop on Biomedical Engineering (10thBioEng)},
	pages = {pp. 1-7}
}
@conference {
	title = {Return Channel Performance Evaluation of Enhanced SAMA VSAT with FMCSA and ACM Capability},
	author = {Perumal, Senni., Baras, John S., Roy-Chowdhury, Ayan., Petluri, Hemant S., Robinson, Mitch.},
	year = {2011},
	month = {10/2011},
	abstract = {In this paper, we describe our work on developing and evaluating detailed OPNET simulation models of an enhanced Very Small Aperture Terminal (VSAT) satellite Internet gateway and an enhanced satellite hub based on Cerona SkySPAN technology with capacity and latency optimizations in the return channel so as to allow significantly higher number of users and a better user experience. The Cerona SkySPAN technology uses Digital Video Broadcast via Satellite 2nd standard (DVB-S2) in the forward channel and Spread Aloha Multiple Access (SAMA) protocol in the return channel. We augment the SAMA return channel protocol with Fast Multi-Channel Slotted Aloha (FMCSA) protocol and Adaptive Coding and Modulation (ACM). FMCSA combines Multi-Channel Slotted Aloha (MCSA) with packet level forward error correction (FEC) for new messages and scheduled retransmissions for partially received messages. This protocol increases the maximum possible throughput of SAMA, thus supporting higher number of users. FMCSA also reduces the delay of multi-slot short messages (e.g., HTTP requests) while providing more robust delay performance with respect to load fluctuations, thus resulting in a better user experience. We incorporate Adaptive Coding and Modulation in the return channel in order to automatically adapt the coding and modulation to changing channel conditions so as to ensure remote data service irrespective of the channel degradation due to interference, rain fade or other conditions. We show via OPNET simulations that the enhanced SAMA VSAT with FMCSA and ACM improves the throughput, latency and robustness of the SkySPAN SAMA system. We also compare, via OPNET simulations, the enhanced SAMA system (with FMCSA and ACM) with a DVBRCS system to show improvements in user experience.},
	address = {Palermo, Italy},
	booktitle = {17th Ka and Broadband Communications, Navigation and Earth Observation Conference},
	pages = {pp. 417-424}
}
@conference {
	title = {Wireless Information Infrastructures and the Future Internet:  Protocol Components, System Architectures, Security and Privacy},
	author = {Baras, John S.},
	year = {2011},
	month = {10/2011},
	abstract = {Broadband Communication Infrastructures are expanding rapidly and are becoming ubiquitous. They are affecting every aspect of life and work. They are shaping the architecture, protocols and operation of the evolving future Internet. In this tutorial we describe major recent advances, challenges and opportunities in this critical area, from an integrated systems perspective. Hardware and physical layer advances are making possible new programmable types of networks and services. In the wireless arena physical layer advances mitigate interference (OFDM, MIMO, etc.) and will provide energy and bandwidth efficient and reliable communications. Services over the Future Internet and associated architectures are rapidly expanding and are increasingly interacting and integrated.},
	address = {Brest, France},
	booktitle = {Wireless Personal Multimedia Communications Symposium (WPMC{\textquoteright}11)}
}
@conference {
	title = {Multi-layer Coalitional Games and Agent Communications},
	author = {Baras, John S.},
	year = {2011},
	month = {09/2011},
	address = {Montecello, Illinois},
	booktitle = {49th Annual Allerton Conference}
}
@conference {
	title = {Control Science and Engineering: Providing Foundations for the Emerging Model-Based Systems engineering Discipline},
	author = {Baras, John S.},
	year = {2011},
	month = {09/2011},
	address = {Niskayuna, NY},
	booktitle = {General Electric Research Controls Symposium}
}
@conference {
	title = {Convergence results for the agreement problem on Markovian random topologies},
	author = {Matei, Ion., Baras, John S.},
	year = {2011},
	month = {08/2011},
	abstract = {We study the linear distributed asymptotic agreement(consensus) problem for a network of dynamic agents whose communication network is modeled by a randomly switching graph. The switching is determined by a finite state, Markov process, each topology corresponding to a state of the process. We address both the cases where the dynamics of the agents is expressed in continuous and discrete time. We show that, if the consensus matrices are doubly stochastic, convergence to average consensus is achieved in the mean square and almost sure sense, if and only if the graph resulted from the union of graphs corresponding to the states of the Markov process is strongly connected. The aim of this paper is to show how techniques from the theory of Markovian jump linear systems, in conjunction with results inspired by matrix and graph theory, can be used to prove convergence results for stochastic consensus problems.},
	address = {Milano, Italy},
	booktitle = {2011 IFAC World Conference},
	pages = {pp. 8860-8865}
}
@conference {
	title = {A systems biology model studying the role of cholesterol in Alzheimer{\textquoteright}s disease progression},
	author = {Kyrtsos, C Rose., Baras, John S.},
	year = {2011},
	month = {08/2011},
	abstract = {A simplified network describing the interactions between the cholesterol and beta amyloid (Aβ) synthesis pathways was generated using information available from literature and the KEGG database.~ A system of non-linear differential equations was developed and modeled using several different initial conditions.~ Rate constants were approximated using ratio-metric data from the literature, or by fitting parameters to obtain a stable simulation within given biological constraints.~ Simulations demonstrated the importance of negative feedback control by cholesterol in the regulation of beta-amyloid levels.~ Additionally, the effect of reduced LRP-1 levels and oscillatory cholesterol generation was studied.~},
	address = {Chicago, Illinois},
	booktitle = {ACM Conference on Bioinformatics, Computational Biology and~Biomedicine 2011}
}
@conference {
	title = {Generalized, Multi-criteria, Shortest path Problems on graphs, Idempotent Semirings, Dualities and the Value of Information},
	author = {Baras, John S.},
	year = {2011},
	month = {07/2011},
	abstract = {We investigate generalized shortest path problems on graphs with multiple metrics, that are generalized functions of numerical or logical link "weights". We demonstrate that these problems can be formulated as "linear Optimization or tradeoff problems over partially ordered semirings. We establish conditions for the semirings that guarantee distributed solutions. Considering the information needed for these computations~leads to convexity and duality notions, that help quantify the value of information in these distributed optimization problems.},
	address = {Baltimore, Maryland},
	booktitle = {2011 SIAM Control Conference}
}
@conference {
	title = {Learning and resilience to information deception in adversarial networked systems: the necessity and structure of a trusted core},
	author = {Baras, John S.},
	year = {2011},
	month = {07/2011},
	abstract = {We investigate disturbed inference and learning problems in networked systems with adversaries. We Analyze the effects of adversarial attacks on the solutions and characterize the solution robustness and resiliency as functions of~network topology and adversary distribution. We demonstrate that existence of a small subnetwork of "trusted nodes" (trusted core) could provide substantial improvements to solution robustness and resilience. We characterize these improvements as~functions of the degree of trust, connectivities and location of trusted nodes.},
	address = {Baltimore, Maryland},
	booktitle = {2011 SIAM Control Conference}
}
@conference {
	title = {Cooperative Swarms: the Interplay Between the Collaboration and Communication Multigraphs},
	author = {Baras, John S.},
	year = {2011},
	month = {07/2011},
	address = {Budapest, Hungary},
	booktitle = {Workshop on Flocking, Swarming and Control of Distributed Systems, Foundations of Computational Mathematics (FoCM{\textquoteright}11)}
}
@conference {
	title = {Studying Alzeihmer{\textquoteright}s disease pathogenesis using a systems biology approach},
	author = {Kyrtsos, C Rose., Baras, John S.},
	year = {2011},
	month = {07/2011},
	abstract = {Alzheimer{\textquoteright}s disease (AD) is the most common form of dementia among the elderly, affecting approximately 1 in 6 individuals over the age of 65. To help study the progression of AD, we have developed a mixed metabolic-lipidomic-proteomic network to represent the key interactions in pathways that have been linked to AD. We will present simulation results which study how robust feedback plays an important role in the disease process, as well as how varying cholesterol and LRP concentration levels affects the level of beta amyloid in the system, such as is seen in AD.},
	address = {Seattle, Washington},
	booktitle = {Systems Biology Symposium 2011 (ISB 2011)}
}
@conference {
	title = {Selfish response to Epidemic Propagation},
	author = {Theodorakopoulos, George., Le Boudec, Jean-Yves., Baras, John S.},
	year = {2011},
	month = {06/2011},
	abstract = {An epidemic spreading in a network calls for a decision on the part of the network members: They should decide whether to protect themselves or not. Their decision depends on the trade-off between their perceived risk of being infected and the cost of being protected. The network members can make decisions repeatedly, based on information that they receive about the changing infection level in the network. We study the equilibrium states reached by a network whose members increase (resp. decrease) their security deployment when learning that the network infection is higher (resp. lower). Our main result is that as the learning rate of the members increases, the equilibrium level of infection increases. We demonstrate this result both when members are strictly rational and when they are not. We characterize the domains of attraction of the equilibrium points.We validate our conclusions with simulations on human mobility traces.},
	address = {San Francisco, CA},
	booktitle = {2011 American Control Conference},
	pages = {pp. 4069-4074}
}
@conference {
	title = {The Geometry of a Probabilistic Consensus of Opinion Algorithm},
	author = {Matei, Ion., Baras, John S.},
	year = {2011},
	month = {06/2011},
	abstract = {We consider the problem of a group of agents whose objective is to asymptotically reach agreement of opinion. The agents exchange information subject to a communication topology modeled by a time-varying graph. The agents use a probabilistic algorithm under which at each time instant an agent updates its state by probabilistically choosing from its current state/opinion and the ones of its neighbors. We show that under some minimal assumptions on the communication topology (infinitely often connectivity and bounded intercommunication time between agents), the agents reach agreement with probability one. We show that this algorithm has the same geometric properties as the linear consensus algorithm in Rn. More specifically, we show that the probabilistic update scheme of an agent is equivalent to choosing a point from the (generalized) convex hull of its current state and the states of its neighbors; convex hull defined on a particular convex metric space where the states of the agents live and for which a detailed description is given.},
	address = {San Francisco, CA},
	booktitle = {2011 American Control Conference},
	pages = {pp.  2198-2205}
}
@conference {
	title = {Trust-Assisted Anomaly Detection and Localization in Wireless Sensor Networks},
	author = {Zheng, Shanshan., Baras, John S.},
	year = {2011},
	month = {06/2011},
	abstract = {Fast anomaly detection and localization is critical to ensure effective functioning of wireless sensor networks. The low bandwidth and power constraints in wireless sensor networks are the main challenges for achieving this task, especially for large scale networks. In this paper, we propose a trust-assisted framework for detecting and localizing network anomalies in a hierarchical sensor network. The proposed method makes inference based on end-to-end measurements collected by a set of measurement nodes. Network heterogeneity is exploited for better bandwidth and energy efficiency. The trustworthiness of network links is utilized to design an efficient two-phase probing strategy that can achieve a flexible tradeoff between inference accuracy and probing overhead. We performed experiments with different network settings and demonstrated the effectiveness of our proposed algorithms.},
	address = {Salt Lake City, Utah},
	booktitle = {8th Annual IEEE Communications Society Conference on Sensor, Mesh and Ad Hoc Communications and Networks (SECON) 2011},
	pages = {pp.  386-394}
}
@conference {
	title = {On the complexity of a social behavior model},
	author = {Somarakis, Christoforos., Baras, John S.},
	year = {2011},
	month = {06/2011},
	abstract = {In this paper, we discuss a social behavior model in cellular automata. This model came as a result of research in dynamical structures of networks as these were constructed out of game theory and statistical physics. We define it a dynamical system on the planar grid and study its behavior by varying its parameters under different initial configurations.},
	address = {Quincy, MA},
	booktitle = {Eighth International Conference on Complex Systems (ICCS 2011)},
	pages = {pp.  1330-1344},
	organization = {Boston Marriott}
}
@conference {
	title = {Motif-based Topology Design for Effective Performance by Networks of Mobile Autonomous Vehicles},
	author = {Hovareshti, Pedram., Chen, Hua., Baras, John S.},
	year = {2011},
	month = {06/2011},
	abstract = {To design efficient local connectivity patterns, we have used the idea of network motifs, which was first proposed in the context of biological networks. Network motifs are task specific local connectivity patterns, which exist with much higher frequency in real biological networks compared to those in random networks. These are sub-networks of a low number of nodes (usually 3-4) whose persistence in networks performing similar tasks in different contexts, imply their efficiency in the sense that they optimize certain performance metric in a local scale. We use a simulation test bed to find network motifs for local level communication structures in a collaborative vehicles framework. Here, the group mission consists of several tasks that the agents participate in. The tasks include search operation, data gathering/processing, target finding and leader-follower explorations. Each task gives rise to certain motifs that are specific to that task and the partial knowledge of the environment specifications that the agents operate in. In this way, given the subtasks that are necessary for the mission accomplishment, the most efficient task-specific local topologies are extracted. Switching suitable graphs when the mode of operation is changing can be handled by solving the resulting reachability problem using methods for symbolic planning such as graph grammars. Based on such switching, we also address the effects of split/merge operations on the spectral characteristics of the resulting connectivity graphs.},
	address = {Quincy, MA},
	booktitle = {Eighth International Conference on Complex Systems (ICCS 2011),},
	pages = {pp.  571-573}
}
@conference {
	title = {Cooperative networked systems: Multiple graphs, coalitional games, new probabilistics models},
	author = {Baras, John S.},
	year = {2011},
	month = {06/2011},
	abstract = {The consideration of cooperative networked systems has raised fundamental new questions and challenges. We consider networked systems from various domains including control, communications, sensing, sociology, economics, and biology. We first describe a general model for modeling such systems that involve several interacting dynamic multigraphs. These multigraphs evolve in at least three planes. At the higher plane (layer) we have the network of cognitive agents, where decisions are made and executed. At the intermediate plane (layer) we have the information network, where data, models, observations and signaling are represented. At the lower plane (layer) we have the communication network that supports the information and agent networks. There are several ways to capture these ideas and principles, and the one presented here is one of the simpler possible representations. The lower layer is more connected to the physical layer, while the middle and higher layer is more logical. The networks involve have links and nodes that are annotated by weights that can be scalar, vector or even policies and rules. Furthermore, the networks are dynamic. The resulting dynamic models are very complex and require a combination of methods from analysis, algebra, logic and optimization. The simplest possible model involves two interacting multigraphs: (a) the collaboration multigraph, which describes the time varying relation of collaboration between the agents; and (b) the communication multigraph, which describes the time-varying communications that occur between the agents. We link these concepts to ideas from distributed computing, distributed programs, and distributed computer hardware. We also link this representation to the behavior and structure models used in modern model-based-systems engineering. We describe a novel path-oriented characterization of these activities in networked dynamic systems. Next, we introduce three fundamental problems and challenges emerging from this framework. The first addresses the joint analysis of the collaboration and communication multigraphs and their impact on the performance of the networked system. The second fundamental problem addresses the development of a taxonomy of collaboration and communication multigraphs, from the perspective of system performance. The third fundamental problem addresses the need for different probability models for such cooperative networked systems. We relate the new framework, emerging from the results of the first and second problems, and its basic constructs, to information and control patterns, generalized information theory and entropy, and to distributed computing with local states. This new framework indicates the need for a new kind of probability over dynamical logical structures that is reminiscent of the axiomatic framework of quantum physics.},
	address = {Corfu Island, Greece},
	booktitle = {Control \&amp; Automation (MED), 2011 19th Mediterranean Conference},
	pages = {pp. no. 798-800}
}
@conference {
	title = {Sequential Anomaly Detection in Wireless Networks and Effects of Long Range Dependent Data},
	author = {Baras, John S., Zheng, Shanshan.},
	year = {2011},
	month = {06/2011},
	abstract = {Anomaly detection is an important but difficult task for wireless networks such as mobile ad hoc networks (MANET) and wireless sensor networks (WSN). We present various sequential detection schemes for anomaly detection in such networks including protocol violation, wormhole attacks, fraudulent data injection or algorithm modification. We present both parametric and non parametric algorithms, as well as centralized and distributed schemes. Recent studies have shown that node mobility along with spatial correlations of the monitored traffic in such wireless networks can lead to long range dependent (LRD) traffic, which could significantly increase the difficulty of anomaly detection. We next analyze the effects of LRD traffic on these sequential anomaly detection schemes. Various models of LRD traffic are considered. In the proposed schemes, wavelet transforms are used to approximately de-correlate the traffic data and capture data characteristics at different time scales. The remaining dependencies are then captured by a multilevel hidden Markov model in the wavelet domain. To estimate the model parameters, we proposed an online discounting Expectation Maximization (EM) algorithm, which also tracks variations of the estimated models over time. Network anomalies are then detected as abrupt changes in the tracked model variation scores. We develop statistical properties of these detection schemes as well as performance results, especially stemming from using incorrect short range dependent traffic models.},
	address = {Palo Alto, CA},
	booktitle = {International Workshop on Sequential Methodologies (IWSM 2011)},
	organization = {Stanford University}
}
@conference {
	title = {Challenges and Opportunities for Future Broadband Networks: From Physical to Services to Social},
	author = {Baras, John S.},
	year = {2011},
	month = {06/2011},
	booktitle = {Kick-off meeting of the new center of excellence Labex Comin Labs}
}
@conference {
	title = {Performance Analysis of Time-Critical Peer-to-Peer Communications in IEEE 802.15.4 Networks},
	author = {Wang, Baobing., Baras, John S.},
	year = {2011},
	month = {06/2011},
	abstract = {Existing works on the performance analysis of IEEE 802.15.4 networks with peer-to-peer (P2P) topologies assume the non-beacon unslotted mode in the MAC layer, which is not suitable for time-critical communications required by many applications, such as control, actuation and monitoring applications. In this paper, we introduce an enhanced guaranteed timeslot (GTS) mechanism which can support time-critical P2P communications in wireless sensor networks (WSNs). A Markov chain that takes into account retransmission limits, acknowledgements, unsaturated traffic and packet delivery ratios of links is proposed to model P2P communications using this enhanced GTS mechanism. Based on this model, we analyze the expected reliability and energy consumptions under various traffic conditions. In addition, the impacts of MAC parameters on these performance indexes are analyzed. Monte Carlo simulations show that our theoretical analysis is quite accurate, and thus can be used as guidance for networks configuration in WSNs.},
	address = {Kyoto, Japan},
	booktitle = {IEEE International Conference on Communications (ICC 2011)},
	pages = {pp. 1-6}
}
@conference {
	title = {Exploiting Trust Relations for Nash Equilibrium Efficiency in Ad Hoc Networks},
	author = {Zheng, Shanshan., Jiang, Tao., Baras, John S.},
	year = {2011},
	month = {06/2011},
	abstract = {Ad hoc networks rely on the mutual cooperation among individual nodes to achieve network-wide objectives. However, individual nodes may behave selfishly in order to maximize their own benefits without considering the global benefits of the network. One approach to incentivize nodes cooperation for better global benefits is to establish trust relations among nodes to guide their decision making. In this paper, we present a game theoretic analysis for the efficiency of establishing trust for improving node cooperation. The trust relations among nodes are modeled as a trust-weighted network, and we study a graphical game in this network where the nodes{\textquoteright} payoffs are affected by their trust relations. We characterize the Nash equilibrium and the social optimum of this game and show that the game efficiency has a close relationship to the Bonacich centralities of nodes in the trust-weighted network. Furthermore, we propose to improve game efficiency by introducing heterogeneous resources to nodes according to their centralities. We provide both experimental and theoretical analysis on the improvement of the game efficiency.},
	address = {Kyoto, Japan},
	booktitle = {IEEE International Conference on Communications (ICC 2011)},
	pages = {pp.1-5}
}
@conference {
	title = {A Robust Collaborative Filtering Algorithm Using Ordered Logistic Regression},
	author = {Zheng, Shanshan., Jiang, Tao., Baras, John S.},
	year = {2011},
	month = {06/2011},
	abstract = {The Internet offers tremendous opportunities for information sharing and content distribution. However, without proper filtering and selection, the large amount of information may likely swarm the users rather than benefit them. Collaborative filtering is a technique for extracting useful information from the large information pool generated by interconnected online communities. In this paper, we develop a probabilistic collaborative filtering algorithm, which is based on ordered logistic regression and takes into account both similarities among the users and similarities among the items. We make inference with maximum likelihood and Bayesian frameworks, and propose a Markov Chain Monte Carlo based Expectation Maximization algorithm to optimize model parameters. The power of our proposed algorithm is its extensibility. We show that it can incorporate content and contextual information. More importantly, it can be easily extended to include the trustworthiness of users, thus being more robust to malicious data manipulation. The experimental results on a real world data set show that our proposed algorithm with the trust extension is robust under different types of attacks in recommendation systems.},
	address = {Kyoto, Japan},
	booktitle = {IEEE International Conference on Communications (ICC 2011)},
	pages = {pp. 1-6}
}
@conference {
	title = {Chaos On A Simple Rational Planar Map},
	author = {Somarakis, Christoforos., Baras, John S.},
	year = {2011},
	month = {05/2011},
	abstract = {The dynamics of a 2-D rational map are studied for various values of it{\textquoteright}s control parameters. Despite it{\textquoteright}s simple structure this model is very rich in non-linear phenomena such as, multi-scroll strange attractors, transitions to chaos via period doubling bifurcations, quasi-periodicity as well as intermittency, interior crisis, hyper-chaos etc. In this work, strange attractors, bifurcation diagrams, periodic indows, invariant characteristics are investigated both analytically and numerically.},
	address = {Crete, Greece},
	booktitle = {4th Chaotic Modeling and Simulation International Conference (CHAOS 2011)},
	pages = {pp. 1-9},
	organization = {Agios Nikolaos }
}
@conference {
	title = {AUTHENTICATION OF FINGERPRINT SCANNERS},
	author = {Ivanov, Vladimir I., Baras, John S.},
	year = {2011},
	month = {05/2011},
	abstract = {Fingerprint scanners have unique patterns that can be used to distinguish one scanner from another one. The pattern, which we call scanner pattern, stems from the variability of device characteristics at silicon level and is caused by imperfections of the conversion from the input to the scanner (i.e., the object applied to it) to its output (i.e., the digital image). The scanner pattern is a sufficiently unique and persistent intrinsic characteristic of the fingerprint scanners even to those of the same technology, manufacturer, and model. We propose a simple and extremely accurate algorithm that is able to distinguish the pattern of one scanner from the pattern of another scanner of exactly the same model by extracting the pattern from a single image, acquired with each scanner. In this way, the scanner pattern can be used to enhance the security of a biometric system by authenticating the scanner, used to acquire a particular fingerprint image, and thus detect attacks on the scanner. Combining the biometric authentication with a scanner authentication leads to a two-part authentication, which we call bipartite authentication, that verifies both the identity of the user and the {\textquotedblleft}identity{\textquotedblright} of the fingerprint scanner.},
	address = {Prague, Czech Republic},
	booktitle = {1993 IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP 2011)},
	pages = {pp.  1912-1915}
}
@conference {
	title = {Physical Layer Security and Trust Mechanisms: Critical and Indispensable},
	author = {Baras, John S.},
	year = {2011},
	month = {04/2011},
	address = {Washington DC},
	booktitle = {2nd Army Research Office Special Workshop on Hardware Assurance}
}
@conference {
	title = {Network Science Principles and Cooperative Networked Systems},
	author = {Baras, John S.},
	year = {2011},
	month = {03/2011},
	address = {Beijing, China},
	booktitle = {The Institute of Systems Science (ISS) of the Chinese Academy of Mathematics and Systems Science (AMSS)}
}
@conference {
	title = {Studying Real-time Traffic in Multi-hop Networks Using the EMANE Emulator: Capabilities and Limitations},
	author = {Jain, Kaustubh., Roy-Chowdhury, Ayan., Somasundaram, Kiran K., Wang, Baobing., Baras, John S.},
	year = {2011},
	month = {03/2011},
	abstract = {In this paper, we provide an open-source software emulator setup for MANETs and study its fidelity in providing reliable performance estimates for real-time traffic. We emulate the IEEE 802.11 MAC/PHY (DCF) using the EMANE software emulator deployed on a cluster and run experiments for different multi-hop wireless scenarios. As an instance, we study the performance of real-time streaming media over a mesh network supported by OLSR. We also use the setup to analyze the impact of the wireless network on the self-similarity of the traffic.},
	address = {Barcelona, Spain},
	booktitle = {SIMUTools 2011- 4th International Conference on Simulation Tools and Techniques},
	pages = {pp. 93-95}
}
@conference {
	title = {Component-based Architectures for the Synthesis of Intelligent Networked Systems},
	author = {Baras, John S.},
	year = {2011},
	month = {03/2011},
	abstract = {Advances in Information Technology have enabled the design of complex networked systems, with large number of heterogeneous components and capable of multiple complex functions. These advances have at the same time increased the capabilities of such systems and have increased their complexity to such an extent that systematic design towards predictable performance is extremely difficult if not unfeasible today. This is especially manifested in the area of cyber-physical systems, of all scales, that have become ubiquitous. In addition, the need for systems that can rapidly adapt to new situations and change their structure and behavior accordingly has also increased dramatically. We present methodologies that show promise in addressing these challenges. They include model-based systems engineering, component-based synthesis and architectural design towards efficiency and adaptability. We demonstrate their effectiveness in various applications: collaborative robotics, collaborative heterogeneous sensor networks, cyber security of critical infrastructures, human-machine teams and organizations, and composite trust.},
	address = {Kunming, China},
	booktitle = {IEEE-CYBER 2011},
	pages = {pp. 10-11}
}
@conference {
	title = {Modeling Alzheimer{\textquoteright}s Disease Using A Systems Biology Approach},
	author = {Kyrtsos, C Rose., Baras, John S.},
	year = {2011},
	month = {03/2011},
	abstract = {Alzheimers disease (AD) is the most common form of dementia afflicting the elderly today and is believed to be caused by the buildup of the beta amyloid protein (A{\ss}) within the brain and cerebral vasculature. Although a vast amount of knowledge exists, there is currently no definitive understanding of the initiating factor and subsequent pathogenesis, partially due to the difficulty in directly studying or manipulating the brain experimentally. To overcome this problem, we have developed a systems-level network that encompasses metabolic, lipidomic, and proteomic network topologies, taking into account known feedback and regulation mechanisms. By studying the interactions between the different networks computationally, we have identified several nodes which may be key for initiating a change from a healthy network state to a disease state. We have also performed in vivo experiments in APP/Swe/PS1 transgenic mice to study the effect of simvastatin, a cholesterol inhibitor and potent anti-inflammatory, on the expression levels of A{\ss}, APP, LRP-1 and apoE. These experiments, in combination with our computational model, help to identify crucial feedback points and provide the first known attempt to model AD from a systems-level standpoint.},
	address = {Baltimore, MD},
	booktitle = {Proceedings of the 2011 Biophysical Society}
}
@conference {
	title = {Cooperative Networked Systems: Multiple Graphs and Games},
	author = {Baras, John S.},
	year = {2011},
	month = {02/2011},
	address = {Atlanta, Georgia},
	booktitle = {Decision and Control Laboratory Seminar},
	organization = {Georgia Institute of Technology}
}
