University of Wisconsin

Displaying 41-80 of 133 results

  • White Papers // Jan 2011

    Trace Cache: A Low Latency Approach to High Bandwidth Instruction Fetching

    As the issue width of superscalar processors is increased, instruction fetch bandwidth requirements will also increase. It will become necessary to fetch multiple basic blocks per cycle. Conventional instruction caches hinder this effort because long instruction sequences are not always in contiguous cache locations. The authors propose supplementing the conventional...

    Provided By University of Wisconsin

  • White Papers // Jan 2011

    Matchmaking: Distributed Resource Management for High Throughput Computing

    Conventional resource management systems use a system model to describe resources and a centralized scheduler to control their allocation. The authors argue that this paradigm does not adapt well to distributed systems, particularly those built to support high-throughput computing. Obstacles include heterogeneity of resources, which make uniform allocation algorithms difficult...

    Provided By University of Wisconsin

  • White Papers // Jan 2011

    Program Analysis Via Graph Reachability

    This paper describes how a number of program-analysis problems can be solved by transforming them to graph-reachability problems. Some of the program-analysis problems that are amenable to this treatment include program slicing, certain dataflow-analysis problems, one version of the problem of approximating the possible "Shapes" that heap-allocated structures in a...

    Provided By University of Wisconsin

  • White Papers // Jan 2011

    An Incremental Algorithm for Maintaining the Dominator Tree of a Reducible Flowgraph

    The authors present a new incremental algorithm for the problem of maintaining the dominator tree of a reducible flowgraph as the flowgraph undergoes changes such as the insertion and deletion of edges. Such an algorithm has applications in incremental dataflow analysis and incremental compilation. The contribution of this paper is...

    Provided By University of Wisconsin

  • White Papers // Jan 2011

    Model Checking X86 Executables With CodeSurfer/x86 and WPDS++

    This paper presents a toolset for model checking x86 executables. The members of the toolset are CodeSurfer/x86, WPDS++, and the Path Inspector. CodeSurfer/x86 is used to extract a model from an executable in the form of a weighted pushdown system. WPDS++ is a library for answering generalized reachability queries on...

    Provided By University of Wisconsin

  • White Papers // Jan 2011

    Implementing OKBC Knowledge Model Using Object Relational Capabilities of Oracle 8

    PERK is a storage system that loads Knowledge Bases (KB) from the Oracle DBMS. Its current limitation is the inability to do client-side memory flushing out. In this paper, the authors present a new architecture, named PERK-II, which utilizes the object relational capabilities provided by Oracle 8. It can do...

    Provided By University of Wisconsin

  • White Papers // Jan 2011

    HijackGL: Reconstructing From Streams for Stylized Rendering

    This work shows that intercepting a low-level graphics library command stream and reconstructing a declarative representation is practical and useful, especially for exploring new rendering styles. The authors show not only how the basic mechanics of intercepting an OpenGL command stream lead to a non-invasive extension mechanism for graphics applications,...

    Provided By University of Wisconsin

  • White Papers // Jan 2011

    On Generalized Authorization Problems

    This paper defines a framework in which one can formalize a variety of authorization and policy issues that arise in access control of shared computing resources. Instantiations of the framework address such issues as privacy, recency, validity, and trust. The paper presents an efficient algorithm for solving all authorization problems...

    Provided By University of Wisconsin

  • White Papers // Jan 2011

    High Throughput Data Transfers Using the Tornado Transport Protocol

    The need to transfer extremely large files over very high bandwidth network paths is becoming more and more common. Current window based transport protocols often limit throughput to a level well below what might otherwise be achievable. In this paper the authors describe and evaluate the Tornado Transport Protocol (TTP)...

    Provided By University of Wisconsin

  • White Papers // Jan 2011

    Evaluating and Modeling Window Synchronization in Highly Multiplexed Flows

    In this paper, the authors investigate issues of synchronization in highly aggregated flows such as would be found in the Internet backbone. Understanding this phenomenon is important since it leads to reduced network utilization. The hypothesis is that regularly spaced loss events lead to window synchronization in long lived flows....

    Provided By University of Wisconsin

  • White Papers // Jan 2011

    Resource Deployment Based on Autonomous System Clustering

    Effective placement of resources used to support distributed services in the Internet depends on an accurate representation of Internet topology and routing. Representations of Autonomous System (AS) level topology derived solely from BGP tables show only a subset of the connections that actually get used. However, in many cases, missing...

    Provided By University of Wisconsin

  • White Papers // Jan 2011

    Using Slicing to Identify Duplication in Source Code

    Programs often have a lot of duplicated code, which makes both understanding and maintenance more difficult. This problem can be alleviated by detecting duplicated code, extracting it into a separate new procedure, and replacing all the clones (The instances of the duplicated code) by calls to the new procedure. This...

    Provided By University of Wisconsin

  • White Papers // Jan 2011

    Failure Analysis of SGI XFS File System

    Commodity file systems expect a fail stop disk. But to-days disks fail in unexpected ways. Disks exhibit latent sector errors, silent corruption and transient failures to name a few. In this paper the authors study the behavior of SGI XFS to such errors. File systems play a key role in...

    Provided By University of Wisconsin

  • White Papers // Dec 2010

    Analyzing Capsicum for Usability and Performance

    In this paper the author investigates Capsicum, an ex-tension to UNIX that introduces a new security model on top of existing UNIX architecture. This model consists of several new security primitives and system calls that re-place existing UNIX functionality. The author focused on two aspects of Capsicum: performance and usability....

    Provided By University of Wisconsin

  • White Papers // Dec 2010

    Tuffy: Scaling Up Statistical Inference in Markov Logic Networks

    Markov Logic Networks (MLNs) have emerged as a powerful framework that combines statistical and logical reasoning; they have been applied to many data intensive problems including information extraction, entity resolution, and text mining. Current implementations of MLNs do not scale to real-world data sets, which is preventing their wide-spread adoption....

    Provided By University of Wisconsin

  • White Papers // Dec 2010

    Identifying Activity

    Identification of active constraints in constrained optimization is of interest from both practical and theoretical viewpoints, as it holds the promise of reducing an inequality-constrained problem to an equality-constrained problem, in a neighborhood of a solution. The authors study this issue in the more general setting of composite nonsmooth minimization,...

    Provided By University of Wisconsin

  • White Papers // Dec 2010

    Liquidity, Risk, And Occupational Choices

    The authors explore which financial constraints matter the most in the choice of becoming an entrepreneur. They consider a randomly assigned welfare program in rural Mexico and show that cash transfers significantly increase entry into entrepreneurship. They then exploit the cross-household variation in the timing of these transfers and find...

    Provided By University of Wisconsin

  • White Papers // Oct 2010

    On the Success of Network Topology Inference Using a Markov Random Walk Model for Nested Routing Policies

    Network topology inference is a topic of ongoing interest, as researchers continue to try to identify the topology of the internet, other networks, and the people own networks for maintenance purposes. In this paper, the authors explain why a simple algorithm based on network co-occurrence measurements and a Markov random...

    Provided By University of Wisconsin

  • White Papers // Sep 2010

    Secure Computations on Non-Integer Values

    In this paper the authors present for the first time a framework that allows secure two-party computations on approximations of real valued signals. In the solution, they use a quantized logarithmic representation of the signal samples, which enables to represent both very small and very large numbers with bounded relative...

    Provided By University of Wisconsin

  • White Papers // Sep 2010

    Towards Automatically Checking Thousands of Failures With Micro-Specifications

    Recent data-loss incidents have shown that existing large distributed systems are still vulnerable to failures. To improve the situation, the authors propose two new testing approaches: Failure Testing Service (FTS) and Declarative Testing Specification (DTS). FTS enables one to systematically push a system into thousands of failure scenarios, leading to...

    Provided By University of Wisconsin

  • White Papers // Aug 2010

    Accelerated Block-Coordinate Relaxation for Regularized Optimization

    The authors discuss minimization of a smooth function to which is added a regularization function that induces structure in the solution. A block-coordinate relaxation approach with proximal linearized subproblems yields convergence to stationary points, while identification of the optimal manifold (Under a nondegeneracy condition) allows acceleration techniques to be applied...

    Provided By University of Wisconsin

  • White Papers // Jun 2010

    Dynamic Processors Demand Dynamic Operating Systems

    The rise of multicore processors has lead to techniques that dynamically vary the set and characteristics of cores or threads available to the operating system. For example, Core Fusion merges multiple cores for faster processing. While the mechanics of the change, such as merging two cores into a more powerful...

    Provided By University of Wisconsin

  • White Papers // Jun 2010

    The Case for Fine-Grained Traffic Engineering in Data Centers

    In recent years, several techniques have been suggested for routing and traffic engineering in data centers. However, not much is known about how these techniques perform relative to each other under realistic data center traffic patterns. The preliminary study reveals that existing techniques can only achieve 80% to 85% of...

    Provided By University of Wisconsin

  • White Papers // Jun 2010

    Automatic Generation of Remediation Procedures for Malware Infections

    Despite the widespread deployment of malware detection software, in many situations it is difficult to preemptively block a malicious program from infecting a system. Rather, signatures for detection are usually available only after malware have started to infect a large group of systems. Ideally, infected systems should be reinstalled from...

    Provided By University of Wisconsin

  • White Papers // May 2010

    FlashVM: Virtual Memory Management on Flash

    With the decreasing price of flash memory, systems will increasingly use solid-state storage for virtual-memory paging rather than disks. FlashVM is a system architecture and a core virtual memory subsystem built in the Linux kernel that uses dedicated flash for paging. FlashVM focuses on three major design goals for memory...

    Provided By University of Wisconsin

  • White Papers // May 2010

    Garuda: A Cloud-Based Job Scheduler

    The authors present the design and implementation details of Garuda, a cloud based job scheduler using Google App Engine as the underlying cloud provider. The goal of the project is to demonstrate the concept of a centralized cloud based job scheduler that manages a pool of worker machines and schedules...

    Provided By University of Wisconsin

  • White Papers // Apr 2010

    Extensible and Scalable Network Monitoring Using OpenSAFE

    Administrators of today's networks are highly interested in monitoring traffic for purposes of collecting statistics, detecting intrusions, and providing forensic evidence. Unfortunately, network size and complexity can make this a daunting task. Aside from the problems in analyzing network traffic for this information - an extremely difficult task itself -...

    Provided By University of Wisconsin

  • White Papers // Mar 2010

    Model Evolution: An Incremental Approach to Non-Rigid Structure From Motion

    In this paper, the authors present a new framework for Non-Rigid Structure From Motion (NRSFM) that simultaneously addresses three significant challenges: severe occlusion, perspective camera projection, and large non-linear deformation. They introduce a concept called a model graph, which greatly reduces the computational cost of discovering groups of input images...

    Provided By University of Wisconsin

  • White Papers // Mar 2010

    Financial Crises And Labor Market Turbulence

    Financial crises cause a significant reallocation of labor as relative prices change drastically and economies confront a variety of shocks. Using household survey data for Mexico, the authors show that gross and net labor flows between industries and occupations increase substantially during the 1994-95 crises. They also find significant wage...

    Provided By University of Wisconsin

  • White Papers // Mar 2010

    Peeking Into the Cloud: Toward User-Driven Cloud Management

    The emergence and growing popularity of cloud computing signals an evolution in the way IT infrastructure and services are delivered and consumed. Cloud services have a number of essential characteristics, such as self-service on-demand consumption, location independence, and rapid elasticity. There are also evolving cloud delivery models, including Infrastructure-as-a-Service (IaaS),...

    Provided By University of Wisconsin

  • White Papers // Mar 2010

    A Decision Procedure for Detecting Atomicity Violations for Communicating Processes With Locks

    The problem of interest is to verify data consistency of a concurrent Java program. In particular, the authors present a new decision procedure for verifying that a class of data races caused by inconsistent accesses on multiple fields of an object cannot occur (So-called atomic-set serializability). Atomic-set serializability generalizes the...

    Provided By University of Wisconsin

  • White Papers // Mar 2010

    EndRE: An End-System Redundancy Elimination Service for Enterprises

    In many enterprises today, WAN optimizers are being deployed in order to eliminate redundancy in network traffic and reduce WAN access costs. In this paper, the authors present the design and implementation of EndRE, an alternate approach where Redundancy Elimination (RE) is provided as an end system service. Unlike middleboxes,...

    Provided By University of Wisconsin

  • White Papers // Mar 2010

    Cheap and Large CAMs for High Performance Data-Intensive Networked Systems

    The authors show how to build cheap and large CAMs, or CLAMs, using a combination of DRAM and flash memory. These are targeted at emerging data-intensive networked systems that require massive hash tables running into a hundred GB or more, with items being inserted, updated and looked up at a...

    Provided By University of Wisconsin

  • White Papers // Jan 2010

    Scientific Workflow Management by Database Management

    In several working environments, production involves repeated executions of certain procedures. A workflow describes the individual tasks performed in these procedures and their interrelationships. Current Workflow Management Systems (WFMSs) use a Database Management System (DBMS) to store task descriptions, and implement all workflow functionality in modules that run on top...

    Provided By University of Wisconsin

  • White Papers // Jan 2010

    Laying the Foundation for the Investigation of the Quality of Service for Resource Management in Grid Computing

    By pooling the resources of virtually any functional machine, grids have quickly become a powerful, low-cost, attractive solution in a number of application domains. As a result of the surge in interest in grid computing, a variety of implementations have emerged. The availability of grid systems in commercial industry is...

    Provided By University of Wisconsin

  • White Papers // Jan 2010

    Nest - A Grid Enabled Storage Appliance

    This paper describes NeST, a flexible software-only storage appliance designed to meet the storage needs of the Grid. NeST has three key features that make it well suited for deployment in a Grid environment. First, NeST provides a generic data transfer architecture that supports multiple data transfer protocols including GridFTP...

    Provided By University of Wisconsin

  • White Papers // Jan 2010

    Phase III: Data Recovery and Mitigation

    Data recovery may be undertaken as a form of mitigation at an archeological site determined eligible for listing on the National Register of Historic Places and that will be impacted by a proposed federal undertaking. Data recovery is undertaken when neither preservation in place nor avoidance through project redesign is...

    Provided By University of Wisconsin

  • White Papers // Jan 2010

    A DBMS Engine Simulator to Assist in Classroom Understanding of Oracle Query Execution

    Oracle's DBMS query execution process consists of a complicated series of steps which can be difficult for many students and professionals to understand. It is also difficult to find resources which provide a compiled description of this process and all of the components involved. The authors have researched Oracle's DBMS...

    Provided By University of Wisconsin

  • White Papers // Dec 2009

    Multi-View 3D Geometry Reconstruction: Exploiting Massive Parallelism

    3D geometric reconstruction from digital images captured from consumer cameras is an inexpensive, but computationally demanding application. In this experimental study, the authors have explored parallelism in the best known public domain software (Bundler and PMVS2) and found that massive parallelism exists at various levels that can be exploited on...

    Provided By University of Wisconsin

  • White Papers // Dec 2009

    E-Mobile: A Heterogeneous Agent-Based, Remote Off-Loading Framework for Efficient Energy Management of Mobile Devices

    Web applications are becoming increasingly popular on mobile/wireless devices. As more desktop applications that are inherently computational intensive and resource-demanding are being ported to the mobile platforms, the energy consumption of the devices is shooting up, thereby decreasing the battery life. An alternate approach is to off-load the resource intensive...

    Provided By University of Wisconsin

  • White Papers // Jan 2011

    Caching for Multi-Dimensional Data Mining Queries

    Multi-dimensional data analysis and online analytical processing are standard querying techniques applied on today's data warehouses. Data mining algorithms, on the other hand, are mostly run in stand-alone, batch mode on at les extracted from relational databases. In this paper the authors propose a general querying model combining the power...

    Provided By University of Wisconsin

  • White Papers // Jan 2011

    Multiprocessor Scheduling Using Dynamic Performance Measurement and Analysis

    In this paper the authors address using dynamic performance metrics when making scheduling decisions. The focus is on the problem of cache affinity in multiprocessor CPU schedulers. The Linux 2.4 kernel uses a simplistic method to determine cache affinity, one that does not take into account the working set size...

    Provided By University of Wisconsin

  • White Papers // Jan 2011

    Program Generalization for Software Reuse: From C to C++

    The authors consider the problem of software generalization: Given a program component C, create a parameterized program component C' such that C' is usable in a wider variety of syntactic contexts than C. Furthermore, C' should be a semantically meaningful generalization of C; namely, there must exist an instantiation of...

    Provided By University of Wisconsin

  • White Papers // Jan 2011

    Modeling Congestion in Backbone Routers

    Traffic engineering models based on end-to-end loss probabilities and delays do not scale well to fast backbone links. In this paper, the authors investigate the nature of congestion events in highly aggregated flows. An examination of congestion events shows distinct phases of queue buildup, packet dropping followed later by TCP...

    Provided By University of Wisconsin

  • White Papers // Aug 2010

    Accelerated Block-Coordinate Relaxation for Regularized Optimization

    The authors discuss minimization of a smooth function to which is added a regularization function that induces structure in the solution. A block-coordinate relaxation approach with proximal linearized subproblems yields convergence to stationary points, while identification of the optimal manifold (Under a nondegeneracy condition) allows acceleration techniques to be applied...

    Provided By University of Wisconsin

  • White Papers // Jan 2011

    Inferring Regulatory Networks From Time Series Expression Data and Relational Data Via Inductive Logic Programming

    In this paper, the authors are interested in learning rules that will reveal the causal genes for the expression variation from various relational data sources in addition to gene expression data. Following the previous work where they showed that time series gene expression data could potentially uncover causal effects, they...

    Provided By University of Wisconsin

  • White Papers // Dec 2010

    Identifying Activity

    Identification of active constraints in constrained optimization is of interest from both practical and theoretical viewpoints, as it holds the promise of reducing an inequality-constrained problem to an equality-constrained problem, in a neighborhood of a solution. The authors study this issue in the more general setting of composite nonsmooth minimization,...

    Provided By University of Wisconsin

  • White Papers // Apr 2009

    A Thread-Wise Strategy for Incremental Crawling of Web Forums

    The authors study in this paper the problem of incremental crawling of web forums, which is a very fundamental yet challenging step in many web applications. Traditional approaches mainly focus on scheduling the revisiting strategy of each individual page. However, simply assigning different weights for different individual pages are usually...

    Provided By University of Wisconsin

  • White Papers // Dec 2010

    Tuffy: Scaling Up Statistical Inference in Markov Logic Networks

    Markov Logic Networks (MLNs) have emerged as a powerful framework that combines statistical and logical reasoning; they have been applied to many data intensive problems including information extraction, entity resolution, and text mining. Current implementations of MLNs do not scale to real-world data sets, which is preventing their wide-spread adoption....

    Provided By University of Wisconsin

  • White Papers // Sep 2009

    Network Anomaly Confirmation, Diagnosis and Remediation

    Identifying and diagnosing network traffic anomalies, and rectifying their effects are standard, daily activities of network operators. While there is a large and growing literature on techniques for detecting network anomalies, there has been little or no treatment of what to do after a candidate anomaly has been identified. In...

    Provided By University of Wisconsin

  • White Papers // Jan 2012

    Phantom: Physical Layer Cooperation for Location Privacy Protection

    Localization techniques that allow inferring the location of wireless devices directly from received signals have exposed mobile users to new threats. Adversaries can easily collect required information (such as signal strength) from target users, however, techniques securing location information at the physical layer of the wireless communication systems have not...

    Provided By University of Wisconsin

  • White Papers // May 2012

    A Passive Measurement System for Network Testbeds

    The ability to capture and process packet-level data is of intrinsic importance in network testbeds that offer broad experimental capabilities to researchers. In this paper, the authors describe the design and implementation of a passive measurement system for network testbeds called GIMS. The system enables users to specify and centrally...

    Provided By University of Wisconsin

  • White Papers // Dec 2009

    Enhancing Simulation Mode Operation of Ospfd

    In this paper, the authors describe their modifications to ospfd, a popular open-source implementation of OSPF routing protocol. The ospfd software can also be run in simulation mode, where processes, representing individual routers, communicate with each other over UDP sockets. Even though ospfd provides a fine-granularity implementation of OSPF protocol,...

    Provided By University of Wisconsin

  • White Papers // Jun 2009

    Analyzing the Hold Time Schemes to Limit the Routing Table Calculations in OSPF Protocol

    OSPF is a popular interior gateway routing protocol. Commercial OSPF routers limit their processing load by using a hold time between successive routing table calculations as new Link State Advertisements (LSAs) arrive following a topology change. A large hold time value limits the frequency of routing table calculations but also...

    Provided By University of Wisconsin

  • White Papers // Jun 2008

    Scheduling Routing Table Calculations to Achieve Fast Convergence in OSPF Protocol

    Fast convergence to topology changes is now a key requirement in routing infrastructures while reducing the routing protocol's processing overhead continues to be as important as before. In this paper, the authors examine the problem of scheduling routing table updates in link state routing protocols. Commercial routers typically use a...

    Provided By University of Wisconsin

  • White Papers // May 2012

    Obtaining Representative Measurements of Cellular Network Performance

    Network service providers, and other parties, require an accurate understanding of the performance cellular networks deliver to users. In particular, they often seek a measure of the network performance users experience solely when they are interacting with their device - a measure the authors call representative. Acquiring such measures is...

    Provided By University of Wisconsin

  • White Papers // Aug 2012

    Towards Energy-Efficient Database Cluster Design

    Energy is a growing component of the operational cost for many "Big data" deployments, and hence has become increasingly important for practitioners of large-scale data analysis who require scale-out clusters or parallel DBMS appliances. Although a number of recent studies have investigated the energy efficiency of DBMSs, none of these...

    Provided By University of Wisconsin

  • White Papers // Jun 2012

    Reducing Memory Reference Energy With Opportunistic Virtual Caching

    Most modern cores perform a highly-associative Translation Look aside Buffer (TLB) lookup on every memory access. These designs often hide the TLB lookup latency by overlapping it with L1 cache access, but this overlap does not hide the power dissipated by TLB lookups. It can even exacerbate the power dissipation...

    Provided By University of Wisconsin

  • White Papers // May 2010

    FlashVM: Virtual Memory Management on Flash

    With the decreasing price of flash memory, systems will increasingly use solid-state storage for virtual-memory paging rather than disks. FlashVM is a system architecture and a core virtual memory subsystem built in the Linux kernel that uses dedicated flash for paging. FlashVM focuses on three major design goals for memory...

    Provided By University of Wisconsin

  • White Papers // Aug 2009

    Tolerating Hardware Device Failures in Software

    Hardware devices can fail, but many drivers assume they do not. When confronted with real devices that misbehave, these assumptions can lead to driver or system failures. While major operating system and device vendors recommend that drivers detect and recover from hardware failures, the authors find that there are many...

    Provided By University of Wisconsin

  • White Papers // Feb 2009

    On the Effectiveness of Pre-Acceptance Spam Filtering

    Modern SMTP servers apply a variety of mechanisms to stem the volume of spam delivered to users. These techniques can be broadly classified into two categories: pre-acceptance approaches, which apply prior to a message being accepted (e.g. blacklisting and whitelisting), and post-acceptance techniques which apply after a message has been...

    Provided By University of Wisconsin

  • White Papers // Mar 2010

    EndRE: An End-System Redundancy Elimination Service for Enterprises

    In many enterprises today, WAN optimizers are being deployed in order to eliminate redundancy in network traffic and reduce WAN access costs. In this paper, the authors present the design and implementation of EndRE, an alternate approach where Redundancy Elimination (RE) is provided as an end system service. Unlike middleboxes,...

    Provided By University of Wisconsin

  • White Papers // Sep 2010

    Secure Computations on Non-Integer Values

    In this paper the authors present for the first time a framework that allows secure two-party computations on approximations of real valued signals. In the solution, they use a quantized logarithmic representation of the signal samples, which enables to represent both very small and very large numbers with bounded relative...

    Provided By University of Wisconsin

  • White Papers // Jun 2009

    On some sufficient conditions for distributed Quality-of-Service support in wireless networks

    Given a wireless network where some pairs of communication links interfere with each other, the authors study sufficient conditions for determining whether a given set of minimum bandwidth Quality of Service (QoS) requirements can be satisfied. They are especially interested in algorithms which have low communication overhead and low processing...

    Provided By University of Wisconsin

  • White Papers // Jan 2009

    Mass Collaboration Systems on the World-Wide Web

    Mass collaboration systems enlist a multitude of humans to help solve a wide variety of problems. Over the past decade, numerous such systems have appeared on the World Wide Web. Prime examples include Wikipedia, Linux, Yahoo! Answers, Amazon's Mechanical Turk, and much effort is being directed at developing many more....

    Provided By University of Wisconsin

  • White Papers // Dec 2009

    Toward Industrial-Strength Keyword Search Systems Over Relational Data

    KeyWord Search (KWS) over relational data, where the answers are multiple tuples connected via joins, has received significant attention in the past decade. Numerous solutions have been proposed and many prototypes have been developed. Building on this rapid progress and on growing user needs, recently several RDBMS and Web companies...

    Provided By University of Wisconsin

  • White Papers // Apr 2009

    Flash Aware RAID

    Flash based SSDs are increasing in popularity, performance, and capacity. The advancements made in capacity come at a cost of decreased reliability. Traditional error correcting codes capable of repairing single-bit errors are no longer completely effective as multiple-bit errors grow more common. Because of this, flash based storage should leverage...

    Provided By University of Wisconsin

  • White Papers // Mar 2009

    Detecting and Measuring Similarity in Code Clones

    Most previous work on code-clone detection has focused on finding identical clones, or clones that are identical up to identifiers and literal values. However, it is often important to find similar clones, too. One challenge is that the definition of similarity depends on the context in which clones are being...

    Provided By University of Wisconsin

  • White Papers // Feb 2009

    Evaluating GPUs for Network Packet Signature Matching

    Modern network devices employ deep packet inspection to enable sophisticated services such as intrusion detection, traffic shaping, and load balancing. At the heart of such services is a signature matching engine that must match packet payloads to multiple signatures at line rates. However, the recent transition to complex regular-expression based...

    Provided By University of Wisconsin

  • White Papers // Jan 2011

    Updates for Structure Indexes

    The problem of indexing path queries in semistructured/XML databases has received considerable attention recently, and several proposals have advocated the use of structure indexes as supporting data structures for this problem. In this paper, the authors investigate efficient update algorithms for structure indexes. They study two kinds of updates-the addition...

    Provided By University of Wisconsin

  • White Papers // Mar 2009

    Symbolic Analysis Via Semantic Reinterpretation

    The paper presents a novel technique to create implementations of the basic primitives used in symbolic program analysis: forward symbolic evaluation, weakest liberal precondition, and symbolic composition. The authors used the technique to create a system in which, for the cost of writing just one specification - an interpreter for...

    Provided By University of Wisconsin

  • White Papers // Aug 2009

    Reducing Concurrent Analysis Under a Context Bound to Sequential Analysis

    This paper addresses the analysis of concurrent programs with shared memory. Such an analysis is undecidable in the presence of multiple procedures. One approach used in recent work obtains decidability by providing only a partial guarantee of correctness: the approach bounds the number of context switches allowed in the concurrent...

    Provided By University of Wisconsin

  • White Papers // Jul 2009

    Light Field Video Stabilization

    The authors describe a method for producing a smooth, stabilized video from the shaky input of a hand-held light field video camera - specifically, a small camera array. Traditional stabilization techniques dampen shake with 2D warps, and thus have limited ability to stabilize a significantly shaky camera motion through a...

    Provided By University of Wisconsin

  • White Papers // Jan 2011

    The Design, Implementation, and Evaluation of mpiBLAST

    mpiBLAST is an open-source parallelization of BLAST that achieves superlinear speed-up by segmenting a BLAST database and then having each node in a computational cluster search a unique portion of the database. Database segmentation permits each node to search a smaller portion of the database, eliminating disk I/O and vastly...

    Provided By University of Wisconsin

  • White Papers // Jan 2009

    Estimating Hop Distance Between Arbitrary Host Pairs

    Establishing a clear and timely picture of Internet topology is complicated by many factors including the vast size and dynamic nature of the infrastructure. In this paper, the authors describe a methodology for estimating an important characteristic of Internet topology - the hop distance between arbitrary pairs of end hosts....

    Provided By University of Wisconsin

  • White Papers // Jul 2009

    An Efficient Algorithm for Co-Segmentation

    This paper is focused on the Co-segmentation problem - where the objective is to segment a similar object from a pair of images. The background in the two images may be arbitrary; therefore, simultaneous segmentation of both images must be performed with a requirement that the appearance of the two...

    Provided By University of Wisconsin

  • White Papers // Jan 2011

    Locking Protocols for Materialized Aggregate Join Views

    The maintenance of materialized aggregate join views is a well-studied problem. However, to date the published literature has largely ignored the issue of concurrency control. Clearly immediate materialized view maintenance with transactional consistency, if enforced by generic concurrency control mechanisms, can result in low levels of concurrency and high rates...

    Provided By University of Wisconsin

  • White Papers // Jan 2011

    Formalizing Sensitivity in Static Analysis for Intrusion Detection

    A key function of a host-based intrusion detection system is to monitor program execution. Models constructed using static analysis have the highly desirable feature that they do not produce false alarms; however, they may still miss attacks. Prior work has shown a trade-off between efficiency and precision. In particular, the...

    Provided By University of Wisconsin

  • White Papers // Jan 2011

    Trace Cache: A Low Latency Approach to High Bandwidth Instruction Fetching

    As the issue width of superscalar processors is increased, instruction fetch bandwidth requirements will also increase. It will become necessary to fetch multiple basic blocks per cycle. Conventional instruction caches hinder this effort because long instruction sequences are not always in contiguous cache locations. The authors propose supplementing the conventional...

    Provided By University of Wisconsin

  • White Papers // Jun 2010

    Automatic Generation of Remediation Procedures for Malware Infections

    Despite the widespread deployment of malware detection software, in many situations it is difficult to preemptively block a malicious program from infecting a system. Rather, signatures for detection are usually available only after malware have started to infect a large group of systems. Ideally, infected systems should be reinstalled from...

    Provided By University of Wisconsin