Invited Talks -- The Unpredictable Deviousness of Models -- Security Issues in Collaborative Computing -- Session A -- A Simplicial Approach for Discrete Fixed Point Theorems -- On Incentive Compatible Competitive Selection Protocol -- Edge Pricing of Multicommodity Networks for Selfish Users with Elastic Demands -- Aggregating Strategy for Online Auctions -- On Indecomposability Preserving Elimination Sequences -- Improved Algorithms for the Minmax Regret 1-Median Problem -- Partitioning a Multi-weighted Graph to Connected Subgraphs of Almost Uniform Size -- Characterizations and Linear Time Recognition of Helly Circular-Arc Graphs -- Varieties Generated by Certain Models of Reversible Finite Automata -- Iterated TGR Languages: Membership Problem and Effective Closure Properties -- On the Negation-Limited Circuit Complexity of Sorting and Inverting k-tonic Sequences -- Robust Quantum Algorithms with ?-Biased Oracles -- The Complexity of Black-Box Ring Problems -- Lower Bounds and Parameterized Approach for Longest Common Subsequence -- Finding Patterns with Variable Length Gaps or Don't Cares -- The Matrix Orthogonal Decomposition Problem in Intensity-Modulated Radiation Therapy -- A Polynomial-Time Approximation Algorithm for a Geometric Dispersion Problem -- A PTAS for Cutting Out Polygons with Lines -- On Unfolding Lattice Polygons/Trees and Diameter-4 Trees -- Restricted Mesh Simplification Using Edge Contractions -- Enumerating Non-crossing Minimally Rigid Frameworks -- Sequences Characterizing k-Trees -- On the Threshold of Having a Linear Treewidth in Random Graphs -- Reconciling Gene Trees with Apparent Polytomies -- Lower Bounds on the Approximation of the Exemplar Conserved Interval Distance Problem of Genomes -- Computing Maximum-Scoring Segments in Almost Linear Time -- Session B.-Enumerate and Expand: New Runtime Bounds for Vertex Cover Variants -- A Detachment Algorithm for Inferring a Graph from Path Frequency -- The d-Identifying Codes Problem for Vertex Identification in Graphs: Probabilistic Analysis and an Approximation Algorithm -- Reconstructing Evolution of Natural Languages: Complexity and Parameterized Algorithms -- On Dynamic Bin Packing: An Improved Lower Bound and Resource Augmentation Analysis -- Improved On-Line Broadcast Scheduling with Deadlines -- A Tight Analysis of Most-Requested-First for On-Demand Data Broadcast -- On Lazy Bin Covering and Packing Problems -- Creation and Growth of Components in a Random Hypergraph Process -- Optimal Acyclic Edge Colouring of Grid Like Graphs -- An Edge Ordering Problem of Regular Hypergraphs -- Efficient Partially Blind Signature Scheme with Provable Security -- A Rigorous Analysis for Set-Up Time Models - A Metric Perspective -- Geometric Representation of Graphs in Low Dimension -- The On-Line Heilbronn's Triangle Problem in d Dimensions -- Counting d-Dimensional Polycubes and Nonrectangular Planar Polyominoes -- Approximating Min-Max (Regret) Versions of Some Polynomial Problems -- The Class Constrained Bin Packing Problem with Applications to Video-on-Demand -- MAX-SNP Hardness and Approximation of Selected-Internal Steiner Trees -- Minimum Clique Partition Problem with Constrained Weight for Interval Graphs -- Overlap-Free Regular Languages -- On the Combinatorial Representation of Information -- Finding Small OBDDs for Incompletely Specified Truth Tables Is Hard -- Bimodal Crossing Minimization -- Fixed Linear Crossing Minimization by Reduction to the Maximum Cut Problem -- On the Effectiveness of the Linear Programming Relaxation of the 0-1 Multi-commodity Minimum Cost Network Flow Problem.