Showing papers by "Ming-Yang Kao published in 2007"

Reversible sketches: enabling monitoring and analysis over high-speed data streams

Abstract: A key function for network traffic monitoring and analysis is the ability to perform aggregate queries over multiple data streams. Change detection is an important primitive which can be extended to construct many aggregate queries. The recently proposed sketches are among the very few that can detect heavy changes online for high speed links, and thus support various aggregate queries in both temporal and spatial domains. However, it does not preserve the keys (e. g., source IP address) of flows, making it difficult to reconstruct the desired set of anomalous keys. To address this challenge, we propose the reversible sketch data structure along with reverse hashing algorithms to infer the keys of culprit flows. There are two phases. The first operates online, recording the packet stream in a compact representation with negligible extra memory and few extra memory accesses. Our prototype single FPGA board implementation can achieve a throughput of over 16 Gb/s for 40-byte packet streams (the worst case). The second phase identifies heavy changes and their keys from the representation in nearly real time. We evaluate our scheme using traces from large edge routers with OC-12 or higher links. Both the analytical and experimental results show that we are able to achieve online traffic monitoring and accurate change/intrusion detection over massive data streams on high speed links, all in a manner that scales to large key space size. To the best of our knowledge, our system is the first to achieve these properties simultaneously.

Detecting Stealthy Spreaders Using Online Outdegree Histograms

Abstract: We consider the problem of detecting the presence of a sufficiently large number of hosts that connect to more than a certain number of unique destinations within a given time window, over high-speed networks. We call such hosts stealthy spreaders. In practice, stealthy spreaders can be symptomatic of botnet scans or moderate worm propagation. Previous techniques have focused on detecting sources with an extremely large outdegree. However, such techniques fail to detect spreaders such as bot scans in which each scanning host scans only a moderate, fixed number of destinations. In contrast, our scheme maintains a small, fixed size memory usage, and is still able to detect stealthy spreader scenarios by approximating outdegree histograms from continuous traffic. To the best of our knowledge, we are the first to study the efficient outdegree histogram estimation and stealthy spreader detection problems. Evaluation based on real Internet traffic and botnet scan events show that our scheme is highly accurate and can operate online.

Address generation for nanowire decoders

Abstract: Nanoscale crossbars built from nanowires can form high density memories and programmable logic devices. To integrate such nanoscale devices with CMOS circuits, nanowire decoders were invented. Due to the stochastic nature of the nanoscale fabrication, the decoder addresses that address the nanowires selectively must be generated after fabrication. In this paper, we develop a mathematical model of the nanowire decoders for the generation of the proper addresses. Assuming a simple testing approach calledon-off measurement, we prove that the maximum number of the proper addresses can be generated in finite time. We design the algorithms to generate the required number of the proper addresses. Experimental results confirm the efficiency of our algorithms.

Using nash implementation to achieve better frugality ratios

Abstract: Most of the recent works on algorithmic mechanism design exploit the solution concept of dominant strategy equilibria. Such work designs a proper payment scheme so that selfish agents maximize their utility by truthfully revealing their types. It has been pointed out that these truthful mechanisms, the famous among them being the VCG mechanisms, often incur high payments and fruglity ratios. In this work, we exploit the solution concept of Nash implementation to overcome this problem. Our mechanisms induce a set of Nash equilibria so that selfish agents have incentive to act based on a Nash equilibrium. We prove that our mechanisms enjoy substantial advantages over the truthful mechanisms in terms of payment and frugality.

Algorithmic aspects in information and management : Third International Conference, AAIM 2007, Portland, OR, USA, June 6-8, 2007 : proceedings

Abstract: Contributed Papers To AAIM 2007.- Solving Generalized Maximum Dispersion with Linear Programming.- Significance-Driven Graph Clustering.- An Improved Approximation Algorithm for Maximum Edge 2-Coloring in Simple Graphs.- Digraph Strong Searching: Monotonicity and Complexity.- Algorithms for Counting 2-Sat Solutions and Colorings with Applications.- Collaborative Ranking: An Aggregation Algorithm for Individuals' Preference Estimation.- A Compact Encoding of Rectangular Drawings with Efficient Query Supports.- A New Efficient Algorithm for Computing the Longest Common Subsequence.- Scheduling a Flexible Batching Machine.- Global Search Method for Parallel Machine Scheduling.- Releasing and Scheduling of Lots in a Wafer Fab.- Mixed Criteria Packet Scheduling.- Efficient Algorithms for k-Disjoint Paths Problems on DAGs.- Acyclic Edge Colouring of Outerplanar Graphs.- Smallest Bipartite Bridge-Connectivity Augmentation (Extended Abstract).- Approximation Algorithms for the Graph Orientation Minimizing the Maximum Weighted Outdegree.- An Efficient Algorithm for the Evacuation Problem in a Certain Class of a Network with Uniform Path-Lengths.- Online OVSF Code Assignment with Resource Augmentation.- Optimal Joint Rate and Power Allocation in CDMA Networks.- Suppressing Maximum Burst Size Throughout the Path with Non-work Conserving Schedulers.- How to Play the Majority Game with Liars.- On Satisfiability Games and the Power of Congestion Games.- The Complexity of Algorithms Computing Game Trees on Random Assignments.- An Efficient, and Fast Convergent Algorithm for Barrier Options.- An Ingenious, Piecewise Linear Interpolation Algorithm for Pricing Arithmetic Average Options.- Optimal Order Allocation with Discount Pricing.- Convex Hulls of Point-Sets and Non-uniform Hypergraphs.- Optimal st-Orientations for Plane Triangulations.- Minimum Spanning Tree with Neighborhoods.- An Almost Linear Time 2.8334-Approximation Algorithm for the Disc Covering Problem.- Optimal Field Splitting with Feathering in Intensity-Modulated Radiation Therapy.- Approximating the Maximum Independent Set and Minimum Vertex Coloring on Box Graphs.- BMA *: An Efficient Algorithm for the One-to-Some Shortest Path Problem on Road Maps.- Strip Packing vs. Bin Packing.- Probe Matrix Problems: Totally Balanced Matrices.- Efficiency of Data Distribution in BitTorrent-Like Systems.- Design of a Fuzzy PI Controller to Guarantee Proportional Delay Differentiation on Web Servers.- Improved Approximation Algorithms for Predicting RNA Secondary Structures with Arbitrary Pseudoknots.- A Heuristic Method for Selecting Support Features from Large Datasets.- Invited Lecture.- Game and Market Equilibria: Computation, Approximation, and Smoothed Analysis.- Ad Auctions - Current and Future Research.- Expressive Commerce and Its Application to Sourcing: How We Conducted $25 Billion of Generalized Combinatorial Auctions.