Pinar Yolum

Computer and Information Sciences - ISCIS 2005

Invited Speakers.- Keeping Viruses Under Control.- Online Auctions: Notes on Theory, Practice, and the Role of Agents.- Computer Networks.- A Unified Approach to Survivability of Connection-Oriented Networks.- SCTP Based Framework for Mobile Web Agent.- An Agent-Based Scheme for Efficient Multicast Application in Mobile Networks.- An Enhanced One Way Function Tree Rekey Protocol Based on Chinese Remainder Theorem.- Admission Control for Multicast Routing with Quality of Service in Ad Hoc Networks.- An Efficient On-line Job Admission Control Scheme to Guarantee Deadlines for QoS-Demanding Applications.- A Methodology of Resilient MPLS/VPN Path Management Under Multiple Link Failures.- Sensor and Satellite Networks.- Comparison of Hyper-DAG Based Task Mapping and Scheduling Heuristics for Wireless Sensor Networks.- A Markov-Based Model to Analyze the Temporal Evolution and Lifetime of a Sensor Network.- Power-Efficient Seamless Publishing and Subscribing in Wireless Sensor Networks.- Group-Oriented Channel Protection for Mobile Devices in Digital Multimedia Broadcasting.- IP Traffic Load Distribution in NGEO Broadband Satellite Networks - (Invited Paper).- Cross-Layer Management of Radio Resources in an Interactive DVB-RCS-Based Satellite Network-(Invited Paper).- Aggressive Back off Strategy in Congestion Management Algorithm for DBS-RCS - (Invited Paper).- TCP-Peach++: Enhancement of TCP-Peach+ for Satellite IP Networks with Asymmetrical Bandwidth and Persistent Fades-(Invited Paper).- Security and Cryptography.- Automatic Translation of Serial to Distributed Code Using CORBA Event Channels.- Fault Tolerant and Robust Mutual Exclusion Protocol for Synchronous Distributed Systems.- Exact Best-Case End-to-End Response Time Analysis for Hard Real-Time Distributed Systems.- A Formal Policy Specification Language for an 802.11 WLAN with Enhanced Security Network.- A Generic Policy-Conflict Handling Model.- A Truly Random Number Generator Based on a Continuous-Time Chaotic Oscillator for Applications in Cryptography.- A New Cryptanalytic Time-Memory Trade-Off for Stream Ciphers.- SVM Approach with a Genetic Algorithm for Network Intrusion Detection.- Performance Evaluation.- Modeling Access Control Lists with Discrete-Time Quasi Birth-Death Processes.- Stochastic Bounds on Partial Ordering: Application to Memory Overflows Due to Bursty Arrivals.- QoS Evaluation Method in Multimedia Applications Using a Fuzzy Genetic Rule-Based System.- Impact of Setup Message Processing and Optical Switch Configuration Times on the Performance of IP over Optical Burst Switching Networks.- Characterizing Gnutella Network Properties for Peer-to-Peer Network Simulation.- Computing Communities in Large Networks Using Random Walks.- Fame as an Effect of the Memory Size.- Keeping Viruses Under Control.- Distributed Evaluation Using Multi-agents.- Classification of Volatile Organic Compounds with Incremental SVMs and RBF Networks.- E-Commerce and Web Services.- Agent Based Dynamic Execution of BPEL Documents.- A Fair Multimedia Exchange Protocol.- A Pervasive Environment for Location-Aware and Semantic Matching Based Information Gathering.- A Web Service Platform for Web-Accessible Archaeological Databases.- A WSDL Extension for Performance-Enabled Description of Web Services.- A Novel Authorization Mechanism for Service-Oriented Virtual Organization.- Metrics, Methodology, and Tool for Performance-Considered Web Service Composition.- Brazilian Software Process Reference Model and Assessment Method.- Multiagent Systems.- A Secure Communication Framework for Mobile Agents.- A Novel Algorithm for the Coordination of Multiple Mobile Robots.- Multiagent Elite Search Strategy for Combinatorial Optimization Problems.- Managing Theories of Trust in Agent Based Systems.- Applying Semantic Capability Matching into Directory Service Structures of Multi Agent Systems.- Self-organizing Distribution of Agents over Hosts.- Machine Learning.- Evolutionary Design of Group Communication Schedules for Interconnection Networks.- Memetic Algorithms for Nurse Rostering.- Discretizing Continuous Attributes Using Information Theory.- System Identification Using Genetic Programming and Gene Expression Programming.- ARKAQ-Learning: Autonomous State Space Segmentation and Policy Generation.- Signature Verification Using Conic Section Function Neural Network.- Fusion of Rule-Based and Sample-Based Classifiers - Probabilistic Approach.- Construction of a Learning Automaton for Cycle Detection in Noisy Data Sequences.- Information Retrieval and Natural Language Processing.- A New Trend Heuristic Time-Variant Fuzzy Time Series Method for Forecasting Enrollments.- Using GARCH-GRNN Model to Forecast Financial Time Series.- Boosting Classifiers for Music Genre Classification.- Discriminating Biased Web Manipulations in Terms of Link Oriented Measures.- ORF-NT: An Object-Based Image Retrieval Framework Using Neighborhood Trees.- Text Categorization with Class-Based and Corpus-Based Keyword Selection.- Aligning Turkish and English Parallel Texts for Statistical Machine Translation.- The Effect of Windowing in Word Sense Disambiguation.- Pronunciation Disambiguation in Turkish.- Image and Speech Processing.- Acoustic Flow and Its Applications.- A DCOM-Based Turkish Speech Recognition System: TREN - Turkish Recognition ENgine.- Speaker Recognition in Unknown Mismatched Conditions Using Augmented PCA.- Real Time Isolated Turkish Sign Language Recognition from Video Using Hidden Markov Models with Global Features.- An Animation System for Fracturing of Rigid Objects.- 2D Shape Tracking Using Algebraic Curve Spaces.- A Multi-camera Vision System for Real-Time Tracking of Parcels Moving on a Conveyor Belt.- Selection and Extraction of Patch Descriptors for 3D Face Recognition.- Implementation of a Video Streaming System Using Scalable Extension of H.264.- Blotch Detection and Removal for Archive Video Restoration.- Performance Study of an Image Restoration Algorithm for Bursty Mobile Satellite Channels.- Algorithms and Database Systems.- Polymorphic Compression.- Efficient Adaptive Data Compression Using Fano Binary Search Trees.- Word-Based Fixed and Flexible List Compression.- Effective Early Termination Techniques for Text Similarity Join Operator.- Multimodal Video Database Modeling, Querying and Browsing.- Semantic Load Shedding for Prioritized Continuous Queries over Data Streams.- Probabilistic Point Queries over Network-Based Movements.- Effective Clustering by Iterative Approach.- Recursive Lists of Clusters: A Dynamic Data Structure for Range Queries in Metric Spaces.- Incremental Clustering Using a Core-Based Approach.- Indexing of Sequences of Sets for Efficient Exact and Similar Subsequence Matching.- An Investigation of the Course-Section Assignment Problem.- Crympix: Cryptographic Multiprecision Library.- Optimal Control for Real-Time Feedback Rate-Monotonic Schedulers.- Graphical User Interface Development on the Basis of Data Flows Specification.- Theory of Computing.- Generalizing Redundancy Elimination in Checking Sequences.- A Computable Version of Dinis Theorem for Topological Spaces.- Improved Simulation of Quantum Random Walks.- An Alternative Proof That Exact Inference Problem in Bayesian Belief Networks Is NP-Hard.- Recovering the Lattice of Repetitive Sub-functions.- Epilogue.- Erol Gelenbes Career and Contributions.

Resolving Commitments among Autonomous Agents

Commitments are a powerful representation for modeling multiagent interactions. Previous approaches have considered the semantics of commitments and how to check compliance with them. However, these approaches do not capture some of the subtleties that arise in real-life applications, e.g., e-commerce, where contracts and institutions have implicit temporal references. The present paper develops a rich representation for the temporal content of commitments. This enables us to capture realistic contracts and institutions rigorously, and avoid subtle ambiguities. Consequently, this approach enables us to reason about whether and when exactly a commitment is satisfied or breached and whether it is or ever becomes unenforceable.

Emergent properties of referral systems

Agents must decide with whom to interact, which is nontrivial when no central directories are available. A classical decentralized approach is referral systems, where agents adaptively give referrals to one another. We study the emergent properties of referral systems, especially those dealing with their quality, efficiency, and structure. Our key findings are (1) pathological graph structures can emerge due to some neighbor selection policies and (2) if these are avoided, quality and efficiency depend on referral policies. Further, authorities emerge automatically and the extent of their relative authoritativeness depends on the policies.

Research directions in agent communication

Increasingly, software engineering involves open systems consisting of autonomous and heterogeneous participants or agents who carry out loosely coupled interactions. Accordingly, understanding and specifying communications among agents is a key concern. A focus on ways to formalize meaning distinguishes agent communication from traditional distributed computing: meaning provides a basis for flexible interactions and compliance checking. Over the years, a number of approaches have emerged with some essential and some irrelevant distinctions drawn among them. As agent abstractions gain increasing traction in the software engineering of open systems, it is important to resolve the irrelevant and highlight the essential distinctions, so that future research can be focused in the most productive directions. This article is an outcome of extensive discussions among agent communication researchers, aimed at taking stock of the field and at developing, criticizing, and refining their positions on specific approaches and future challenges. This article serves some important purposes, including identifying (1) points of broad consensus; (2) points where substantive differences remain; and (3) interesting directions of future work.

Structural and semantic similarity metrics for web service matchmaking

Service matchmaking is the process of finding appropriate services for a given set of requirements. We present a novel service matchmaking approach based on the internal process of services. We model service internal processes using finite state machines and use various heuristics to find structural similarities between services. Further, we use a process ontology that captures the semantic relations between processes. This semantic information is then used to determine semantic similarities between processes and to compute match rates of services. We develop a case study to illustrate the benefits of using process-based matchmaking of services and to evaluate strengths of the different heuristics we propose.

Design time analysis of multiagent protocols

Interaction protocols enable agents to communicate with each other effectively. Whereas several approaches exist to specify interaction protocols, none of them has design tools that can help protocol designers catch semantic protocol errors at design time. As research in networking protocols has shown, flawed specifications of protocols can have disastrous consequences. Hence, it is crucial to systematically analyze protocols in time to ensure effective specification. This paper first studies and formalizes important generic properties of commitment protocols that can ease their effective and consistent development significantly. Next, we identify robustness properties of protocols that are useful in determining the applicability of protocols in different settings. Since these properties are formal, they can easily be incorporated in a software tool to (semi-)automate the design and specification of commitment protocols. Where appropriate we provide algorithms that can directly be used to check these properties in such a design tool.

A framework for formal modeling and analysis of organizations

A new, formal, role-based, framework for modeling and analyzing both real world and artificial organizations is introduced. It exploits static and dynamic properties of the organizational model and includes the (frequently ignored) environment. The transition is described from a generic framework of an organization to its deployed model and to the actual agent allocation. For verification and validation of the proposed model, a set of dedicated techniques is introduced. Moreover, where most computational models can handle only two or three layered organizational structures, our framework can handle any arbitrary number of organizational layers. Henceforth, real-world organizations can be modeled and analyzed, as illustrated by a case study, within the DEAL project line

Designing and executing protocols using the event calculus

Multiagent protocols regulate the interactions between agents. In addition to ensuring meaningful conversations, protocols should also respect agents’ autonomy and enable them to interact flexibly to exploit opportunities and to handle exceptions. Our approach to specifying protocols is based on capturing the intrinsic meaning of actions and explicitly representing them as part of the protocol. We model these intrinsic meanings through social commitments. Conceptually, social commitments capture the obligations from one party to another. Operations to create and manipulate commitments, combined with the reasoning rules, enable agents to reason about their interactions. By representing the intrinsic meaning of the actions, we develop protocols that permit the agents to reason about their and others’ behavior during the execution of the protocol, and to modify their actions as best suits them.

Heuristic-Based Approaches for CP-Nets in Negotiation

CP-Nets have proven to be an effective representation for capturing preferences. However, their use in multiagent negotiation is not straightforward. The main reason for this is that CP-Nets capture partial ordering of preferences, whereas negotiating agents are required to compare any two outcomes based on the request and offers. This makes it necessary for agents to generate total orders from their CP-Nets. We have previously proposed a heuristic to generate total orders from a given CP-Net. This paper proposes another heuristic based on Borda count, applies it in negotiation, and compares its performance with the previous heuristic.

Constraint satisfaction as a tool for modeling and checking feasibility of multiagent commitments

Commitments are being used to specify interactions among autonomous agents in multiagent systems. Various formalizations of commitments have shown their strength in representing and reasoning on multiagent interactions. These formalizations mostly study commitment lifecycles, emphasizing fulfillment of a single commitment. However, when multiple commitments coexist, fulfillment of one commitment may have an effect on the lifecycle of other commitments. Since agents generally participate in more than one commitment at a time, it is important for an agent to determine whether it can honor its commitments. These commitments may be the existing commitments of the agent as well as any prospective commitments that the agent plans to participate in. To address this, we develop the concept of commitment feasibility, i.e., whether it is possible for an agent to fulfill a set of commitments all together. To achieve this we generalize the fulfillment of a single commitment to the feasibility of a set of commitments. We then develop a solid method to determine commitment feasibility. Our method is based on the transformation of feasibility into a constraint satisfaction problem and use of constraint satisfaction techniques to come up with a conclusion. We show soundness and completeness of our method and illustrate its applicability over realistic cases.