University of Wisconsin

Displaying 1-40 of 127 results

  • 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 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 // 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 // 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 // Nov 2011

    Design and Performance of Distributed Mechanisms for Flow Admission in Wireless Adhoc 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 complexity. The...

    Provided By University of Wisconsin

  • White Papers // Oct 2011

    Polymorphic Type Inference for Scripting Languages With Object Extensions

    This paper presents a polymorphic type inference algorithm for a small subset of JavaScript. The goal is to prevent accessing undefined members of objects. The authors define a type system that allows explicit extension of objects through add operation and implicit extension through method calls. The type system also permits...

    Provided By University of Wisconsin

  • White Papers // Jul 2011

    Optimal Scheduling Policies With Mutual Information Accumulation in Wireless Networks

    In this paper, the authors aim to develop scheduling policies to maximize the stability region of a wireless network under the assumption that mutual information accumulation is implemented at the physical layer. This enhanced physical layer capability enables the system to accumulate information even when the link between two nodes...

    Provided By University of Wisconsin

  • White Papers // May 2011

    How National And International Financial Development Affect Industrial R&D

    The authors examine the impacts of both domestic and international financial market development on R&D intensities in 22 manufacturing industries in 18 OECD countries for the period 1990- 2003. They take account of such industry characteristics as the need for external financing and the amount of tangible assets. Multiple forms...

    Provided By University of Wisconsin

  • White Papers // Mar 2011

    Flexible Traffic and Host Profiling Via DNS Rendezvous

    The ability to accurately classify network traffic and to perform timely detection of the presence of unwanted classes of traffic has important implications for network operations and security. In recent years, classification has become more challenging due to applications that use ports that are not well-known that overload or masquerade...

    Provided By University of Wisconsin

  • White Papers // Mar 2011

    Power-Awareness Extensions for Network Testbeds

    The escalation in power consumption of networking and communications equipment is of concern to technologists and environmentalists alike. Understanding how and when networking devices consume power is complicated by their lack of instrumentation. Furthermore, standard networking devices are not typically flexible enough to support experiments with new techniques for reducing...

    Provided By University of Wisconsin

  • White Papers // Mar 2011

    Fingerprinting 802.11 Rate Adaptation Algorithms

    The effectiveness of rate adaptation algorithms is an important determinant of 802.11 wireless network performance. The diversity of algorithms that has resulted from efforts to improve rate adaptation has introduced a new dimension of variability into 802.11 wireless networks, further complicating the already difficult task of understanding and debugging 802.11...

    Provided By University of Wisconsin

  • White Papers // Mar 2011

    PIE in the Sky: Online Passive Interference Estimation for Enterprise WLANs

    Trends in enterprise WLAN usage and deployment point to the need for tools that can capture interference in real time. A tool for interference estimation can not only enable WLAN managers to improve network performance by dynamically adjusting operating parameters like the channel of operation and transmit power of access...

    Provided By University of Wisconsin

  • White Papers // Feb 2011

    Secret Key Generation Through OFDM Multipath Channel

    The authors analyze the fundamental limits of key generation and describe an implementation based on error correcting codes. They show that key extraction based on channel coefficients significantly outperforms key extraction based on Received Signal Strength Indicators (RSSI). The development in this paper is based on an IEEE 802.11a Orthogonal...

    Provided By University of Wisconsin

  • White Papers // Jan 2011

    DomainImpute: Inferring Unseen Components in the Internet

    Despite many efforts over the past decade, the ability to generate topological maps of the Internet at the router-level accurately and in a timely fashion remains elusive. Mapping campaigns commonly involve traceroute-like probing that are usually non-adaptive and incomplete, thus revealing only a portion of the underlying topology. In 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 // 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

    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

    Static Program Analysis Via 3-Valued Logic

    This paper reviews the principles behind the paradigm of "Abstract interpretation via 3-valued logic," discusses recent work to extend the approach, and summarizes ongoing research aimed at overcoming remaining limitations on the ability to create program analysis algorithms fully automatically. Static analysis concerns techniques for obtaining information about the possible...

    Provided By University of Wisconsin

  • White Papers // Jan 2011

    Automatic Verification of Strongly Dynamic Software Systems

    Strongly dynamic software systems are difficult to verify. By strongly dynamic, the authors mean that the actors in such systems change dynamically, that the resources used by such systems are dynamically allocated and deallocated, and that for both sets, no bounds are statically known. In this position paper, they describe...

    Provided By University of Wisconsin

  • White Papers // Jan 2011

    A Non-Blocking Parallel Spatial Join Algorithm

    Interest in incremental and adaptive query processing has led to the investigation of equijoin evaluation algorithms that are non-blocking. This investigation has yielded a number of algorithms, including the symmetric hash join, the XJoin, the Ripple Join, and their variants. However, to the knowledge no one has proposed a non-blocking...

    Provided By University of Wisconsin

  • White Papers // Jan 2011

    Analysis of SPKI/SDSI Certificates Using Model Checking

    SPKI/SDSI is a framework for expressing naming and authorization issues that arise in a distributed-computing environment. In this paper, the authors establish a connection between SPKI/SDSI and a formalism known as Pushdown Systems (PDSs). They show that the SPKI/SDSI-to-PDS connection provides a framework for formalizing a variety of certificate-analysis problems....

    Provided By University of Wisconsin

  • White Papers // Jan 2011

    Efficient Context-Sensitive Intrusion Detection

    Model-based intrusion detection compares a process's execution against a program model to detect intrusion attempts. Models constructed from static program analysis have historically traded precision for efficiency. The authors address this problem with the Dyck model, the first efficient statically-constructed context-sensitive model. This model species both the correct sequences of...

    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 // Jan 2011

    Dynamic Interference Adaptation for Wireless Mesh Networks

    Most wireless meshes will have to operate within the crowded unlicensed spectrum that is also shared by numerous uncoordinated 802.11 hotspots. This creates an unpredictable and variable spectrum space that mesh networks need to co-exist within. The authors propose a novel method for adapting to such external interference by dynamically...

    Provided By University of Wisconsin

  • White Papers // Jan 2011

    Heterogeneity in Large Scale Low-Power Ad-Hoc Wireless Sensor Networks

    Wireless sensor networks have recently become a growing area of research and development due to the tremendous number of applications that can greatly benefit from such systems. In the past the majority of research efforts have implicitly assumed homogenous networks. While this is true of certain applications, in this paper...

    Provided By University of Wisconsin

  • White Papers // Jan 2011

    Two Formal Analyses of Attack Graphs

    An attack graph is a succinct representation of all paths through a system that end in a state where an intruder has successfully achieved his goal. Today Red Teams determine the vulnerability of networked systems by drawing gigantic attack graphs by hand. Constructing attack graphs by hand is tedious, error-prone,...

    Provided By University of Wisconsin

  • White Papers // Jan 2011

    Towards Automatic Generation of Vulnerability-Based Signatures

    In this paper the authors explore the problem of creating vulnerability signatures. A vulnerability signature matches all exploits of a given vulnerability, even polymorphic or metamorphic variants. The work departs from previous approaches by focusing on the semantics of the program and vulnerability exercised by a sample exploit instead of...

    Provided By University of Wisconsin

  • White Papers // Jan 2011

    Efficient Filtering in Publish-Subscribe Systems Using Binary Decision Diagrams

    Implicit invocation or publish-subscribe has become an important architectural style for large-scale system design and evolution. The publish-subscribe style facilitates developing large-scale systems by composing separately developed components because the style permits loose coupling between various components. One of the major bottlenecks in using publish-subscribe systems for very large scale...

    Provided By University of Wisconsin

  • White Papers // Jan 2011

    View Learning for Statistical Relational Learning: With an Application to Mammography

    Statistical Relational Learning (SRL) constructs probabilistic models from relational databases. A key capability of SRL is the learning of arcs (In the Bayes net sense) connecting entries in different rows of a relational table, or in different tables. Nevertheless, SRL approaches currently are constrained to use the existing database schema....

    Provided By University of Wisconsin

  • White Papers // Jan 2011

    Tracking the Role of Adversaries in Measuring Unwanted Traffic

    Measurements related to security are being carried out on many sites on the Internet at network ingress points, between specific points on the Internet, and across the wide area Internet. The goals range from identifying sources of and possibly filtering unwanted traffic, to characterizing and coming up with new mechanisms...

    Provided By University of Wisconsin

  • White Papers // Jan 2011

    Design and Evaluation of Alternative Selection Placement Strategies in Optimizing Continuous Queries

    In this paper, the authors design and evaluate alternative selection placement strategies for optimizing a very large number of continuous queries in an Internet environment. Two grouping strategies, PushDown and PullUp, in which selections are either pushed below, or pulled above, joins are proposed and investigated. While the earlier research...

    Provided By University of Wisconsin

  • White Papers // Jan 2011

    Semantics-Preserving Procedure Extraction

    Procedure extract ion is an important program transformation that can be used to make programs easier to understand and maintain, to facilitate code reuse, and to convert "Monolithic" code to modular or object - oriented code. Procedure extraction involves the following steps: The statements to be extracted are identified (by...

    Provided By University of Wisconsin

  • White Papers // Jan 2011

    Adaptive Control for Anonymous Network-Attached Storage

    The authors describe techniques for building an anonymous network-attached storage system. Central to the design is adaptation, which enables higher performance without administrative tuning. Via a range of simulation experiments and a prototype implementation, they quantify the costs of providing anonymous storage and explore the parameters to which system performance...

    Provided By University of Wisconsin

  • White Papers // Jan 2011

    Change of Representation for Statistical Relational Learning

    Statistical Relational learning (SRL) algorithms learn statistical models from relational data, such as that stored in a relational database. The authors previously introduced view learning for SRL, in which the view of a relational database can be automatically modified, yielding more accurate statistical models. The present paper presents SAYU-VISTA, an...

    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 // Oct 2009

    Multi-Byte Regular Expression Matching With Speculation

    Intrusion prevention systems determine whether incoming traffic matches a database of signatures, where each signature in the database represents an attack or a vulnerability. IPSs need to keep up with ever-increasing line speeds, which leads to the use of custom hardware. A major bottleneck that IPSs face is that they...

    Provided By University of Wisconsin

  • White Papers // Jul 2009

    Using Proximity Search to Estimate Authority Flow

    Authority flow and proximity search have been used extensively in measuring the association between entities in data graphs, ranging from the Web to relational and XML databases. These two ranking factors have been used and studied separately in the past. In addition to their semantic differences, a key advantage of...

    Provided By University of Wisconsin

  • White Papers // Apr 2009

    FlashVM: Revisiting the Virtual Memory Hierarchy

    Flash memory is the largest change to storage in recent history. Most research to date has focused on integrating flash as persistent storage in file systems, with little emphasis on virtual memory paging. However, the VM architecture in most of the commodity operating systems is heavily customized for using disks...

    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 // 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 // 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 // Dec 2009

    Protecting Commodity Operating System Kernels From Vulnerable Device Drivers

    Device drivers on commodity operating systems execute with kernel privilege and have unfettered access to kernel data structures. Several recent attacks demonstrate that such poor isolation exposes kernel data to exploits against vulnerable device drivers, for example through buffer overruns in packet processing code. Prior architectures to isolate kernel data...

    Provided By University of Wisconsin

  • White Papers // Aug 2009

    Verifying Information Flow Control Over Unbounded Processes

    Decentralized Information Flow Control (DIFC) systems enable programmers to express a desired DIFC policy, and to have the policy enforced via a reference monitor that restricts interactions between system objects, such as processes and les. Past research on DIFC systems focused on the reference-monitor implementation, and assumed that the desired...

    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 // Aug 2009

    Static Verification of Data-Consistency Properties

    To leverage the increased processing power of modern multicore processors, programmers are left with the burden of writing concurrent programs. A popular language for writing concurrent programs is Java. In Java, a concurrent program consists of multiple threads that execute in parallel and communicate through shared memory. Because the number...

    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 // May 2009

    Tolerating File-System Mistakes With EnvyFS

    The authors introduce EnvyFS, an N-version local file system designed to improve reliability in the face of file-system bugs. EnvyFS, implemented as a thin VFS-like layer near the top of the storage stack, replicates file-system metadata and data across existing and diverse commodity file systems (E.g., ext3, ReiserFS, JFS). It...

    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 // 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 // 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 // Oct 2008

    Finding Concurrency-Related Bugs Using Random Isolation

    This paper describes the methods used in Empire, a tool to detect concurrency-related bugs, namely atomic-set serializability violations in Java programs. The correctness criterion is based on atomic sets of memory locations, which share a consistency property, and units of work, which preserve consistency when executed sequentially. Empire checks that,...

    Provided By University of Wisconsin

  • White Papers // Jan 2011

    Static Program Analysis Via 3-Valued Logic

    This paper reviews the principles behind the paradigm of "Abstract interpretation via 3-valued logic," discusses recent work to extend the approach, and summarizes ongoing research aimed at overcoming remaining limitations on the ability to create program analysis algorithms fully automatically. Static analysis concerns techniques for obtaining information about the possible...

    Provided By University of Wisconsin

  • White Papers // Jan 2011

    Automatic Verification of Strongly Dynamic Software Systems

    Strongly dynamic software systems are difficult to verify. By strongly dynamic, the authors mean that the actors in such systems change dynamically, that the resources used by such systems are dynamically allocated and deallocated, and that for both sets, no bounds are statically known. In this position paper, they describe...

    Provided By University of Wisconsin

  • White Papers // Jan 2011

    A Non-Blocking Parallel Spatial Join Algorithm

    Interest in incremental and adaptive query processing has led to the investigation of equijoin evaluation algorithms that are non-blocking. This investigation has yielded a number of algorithms, including the symmetric hash join, the XJoin, the Ripple Join, and their variants. However, to the knowledge no one has proposed a non-blocking...

    Provided By University of Wisconsin

  • White Papers // May 2009

    Content-Preserving Warps for 3D Video Stabilization

    The authors describe a technique that transforms a video from a hand-held video camera so that it appears as if it were taken with a directed camera motion. The method adjusts the video to appear as if it were taken from nearby viewpoints, allowing 3D camera movements to be simulated....

    Provided By University of Wisconsin

  • White Papers // Jan 2011

    Analysis of SPKI/SDSI Certificates Using Model Checking

    SPKI/SDSI is a framework for expressing naming and authorization issues that arise in a distributed-computing environment. In this paper, the authors establish a connection between SPKI/SDSI and a formalism known as Pushdown Systems (PDSs). They show that the SPKI/SDSI-to-PDS connection provides a framework for formalizing a variety of certificate-analysis problems....

    Provided By University of Wisconsin

  • White Papers // Jan 2011

    Efficient Context-Sensitive Intrusion Detection

    Model-based intrusion detection compares a process's execution against a program model to detect intrusion attempts. Models constructed from static program analysis have historically traded precision for efficiency. The authors address this problem with the Dyck model, the first efficient statically-constructed context-sensitive model. This model species both the correct sequences of...

    Provided By University of Wisconsin

  • White Papers // Nov 2008

    Avoiding File System Micromanagement With Range Writes

    The authors introduce range writes, a simple but powerful change to the disk interface that removes the need for file system micromanagement of block placement. By allowing a file system to specify a set of possible address targets, range writes enable the disk to choose the final on-disk location of...

    Provided By University of Wisconsin

  • White Papers // Mar 2009

    Some New Directions in Graph-Based Semi-Supervised Learning

    In this position paper, the authors first review the state-of-the-art in graph-based semi-supervised learning, and point out three limitations that are particularly relevant to multimedia analysis: Rich data is restricted to live on a single manifold; learning must happen in batch mode; and the target label is assumed smooth on...

    Provided By University of Wisconsin

  • White Papers // Sep 2008

    Toward a Multicore Architecture for Real-Time Ray-Tracing

    Significant improvement to visual quality for real-time 3D graphics requires modeling of complex illumination effects like soft-shadows, reflections, and diffuse lighting interactions. The conventional Z-buffer algorithm driven GPU model does not provide sufficient support for this improvement. This paper targets the entire graphics system stack and demonstrates algorithms, a software...

    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 // 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