University of Wisconsin-Madison

Displaying 1-40 of 52 results

  • White Papers // Jan 2012

    DiskRouter: A Flexible Infrastructure for High Performance Large Scale Data Transfers

    The steady increase in data sets of scientific applications, the trend towards collaborative research and the emergence of grid computing has created a need to move large quantities of data over wide-area networks. The dynamic nature of network makes it difficult to tune data transfer protocols to use the full...

    Provided By University of Wisconsin-Madison

  • White Papers // Nov 2011

    Multi-Instance Security and Its Application to Password-Based Cryptography

    This paper develops a theory of multi-instance (mi) security and applies it to provide the first proof-based support for the classical practice of salting in password-based cryptography. Mi-security comes into play in settings (like password-based cryptography) where it is computationally feasible to compromise a single instance (si), and provides a...

    Provided By University of Wisconsin-Madison

  • White Papers // Sep 2011

    On Some Sufficient Conditions for Distributed QoS 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 complexity. The...

    Provided By University of Wisconsin-Madison

  • White Papers // Jul 2011

    Exploiting Route Diversity in Multi-Packet Transmission Using Mutual Information Accumulation

    The authors consider cooperative communication in a given network using rateless codes. Given a network, a source and a destination, they investigate routing and resource allocation for delivering multiple packets through the network. They propose and design a centralized algorithm which minimizes a given objective under different network resource constraints....

    Provided By University of Wisconsin-Madison

  • White Papers // Apr 2011

    The Best of Both Worlds With On-Demand Virtualization

    Virtualization offers many benefits such as live migration, resource consolidation, and checkpointing. However, there are many cases where the overhead of virtualization is too high to justify for its merits. Most desktop and laptop PCs and many large web properties run natively because the benefits of virtualization are too small...

    Provided By University of Wisconsin-Madison

  • White Papers // Jan 2011

    Profiling Heterogeneous Multi-GPU Systems to Accelerate Cortically Inspired Learning Algorithms

    Recent advances in neuroscientific understanding make parallel computing devices modeled after the human neocortex a plausible, attractive, fault-tolerant, and energy efficient possibility. Such attributes have once again sparked an interest in creating learning algorithms that aspire to reverse engineer many of the abilities of the brain. In this paper the...

    Provided By University of Wisconsin-Madison

  • White Papers // Jan 2011

    A Comparative Study of Handheld and Non-Handheld Traffic in Campus Wi-Fi Networks

    Handheld devices such as smartphones have become a major platform for accessing Internet services. The small, mobile nature of these devices results in a unique mix of network usage. Other studies have used Wi-Fi and 3G wireless traces to analyze session, mobility, and performance characteristics for handheld devices. The authors...

    Provided By University of Wisconsin-Madison

  • White Papers // Jan 2011

    Selectivity Estimation for XML Twigs

    Twig queries represent the building blocks of declarative query languages over XML data. A twig query describes a complex traversal of the document graph and generates a set of element tuples based on the intertwined evaluation (i.e., join) of multiple path expressions. Estimating the result cardinality of twig queries or,...

    Provided By University of Wisconsin-Madison

  • White Papers // Jan 2011

    A Framework for Reliable and Efficient Data Placement in Distributed Computing Systems

    Data placement is an essential part of today's distributed applications since moving the data close to the application has many benefits. The increasing data requirements of both scientific and commercial applications and collaborative access to these data make it even more important. In the current approach, data placement is regarded...

    Provided By University of Wisconsin-Madison

  • White Papers // Jan 2011

    Cortical Columns: Building Blocks for Intelligent Systems

    The neocortex appears to be a very efficient, uniformly structured, and hierarchical computational system. Researchers have made significant efforts to model intelligent systems that mimic these neocortical properties to perform a broad variety of pattern recognition and learning tasks. Unfortunately, many of these systems have drifted away from their cortical...

    Provided By University of Wisconsin-Madison

  • White Papers // Jan 2011

    NiagaraCQ: A Scalable Continuous Query System for Internet Databases

    Continuous queries are persistent queries that allow users to receive new results when they become available. While continuous query systems can transform a passive web into an active environment, they need to be able to support millions of queries due to the scale of the Internet. No existing systems have...

    Provided By University of Wisconsin-Madison

  • White Papers // Jan 2011

    Form-Based Proxy Caching for Database-Backed Web Sites

    The authors explore a new proxy-caching framework that exploits the query semantics of HTML forms. They identify a common class of form-based queries, and study two representative caching schemes for them within this framework: traditional passive query caching, and active query caching, in which the proxy cache can service a...

    Provided By University of Wisconsin-Madison

  • White Papers // Jan 2011

    IDB: Toward the Scalable Integration of Queryable Internet Data Sources

    As the number of databases accessible on the Web grows, the ability to execute queries spanning multiple heterogeneous queryable sources is becoming increasingly important. To date, research in this area has focused on providing semantic completeness, and has generated solutions that work well when querying over a relatively small number...

    Provided By University of Wisconsin-Madison

  • White Papers // Jan 2011

    A Case for Fractured Mirrors

    The Decomposition Storage Model (DSM) vertically partitions all attributes of a given relation. DSM has excellent I/O behavior when the number of attributes touched in the query is small. It also has a better cache footprint than the N-ary Storage Model (NSM) that is used by most database systems. However,...

    Provided By University of Wisconsin-Madison

  • White Papers // Jan 2011

    Improved Histograms for Selectivity Estimation of Range Predicates

    Many commercial database systems maintain histograms to summarize the contents of relations and permit efficient estimation of query result sizes and access plan costs. Although several types of histograms have been proposed in the past, there has never been a systematic study of all histogram aspects, the available choices for...

    Provided By University of Wisconsin-Madison

  • White Papers // Jan 2011

    DBMSs on a Modern Processor: Where Does Time Go?

    Recent high-performance processors employ sophisticated techniques to overlap and simultaneously execute multiple computation and memory operations. Intuitively, these techniques should help database applications, which are becoming increasingly compute and memory bound. Unfortunately, recent studies report that faster processors do not improve database system performance to the same extent as scientific...

    Provided By University of Wisconsin-Madison

  • White Papers // Jan 2011

    A Comparison of Three Methods for Join View Maintenance in Parallel RDBMS

    In a typical data warehouse, materialized views are used to speed up query execution. Upon updates to the base relations in the warehouse, these materialized views must also be maintained. The need to maintain these materialized views can have a negative impact on performance that is exacerbated in parallel RDBMSs,...

    Provided By University of Wisconsin-Madison

  • White Papers // Jan 2011

    Rate-Based Query Optimization for Streaming Information Sources

    Query optimizers typically attempt to minimize response time. While this approach has been and continues to be very successful in traditional environments, in the presence of information sources of differing rates and non-blocking query execution something else is needed. In this paper, the authors propose a framework for rate-based optimization,...

    Provided By University of Wisconsin-Madison

  • White Papers // Jan 2011

    Dynamic Re-Grouping of Continuous Queries

    In this paper, the authors design and evaluate an efficient and dynamic regrouping approach to optimize a large continuous query workload. The key idea of the authors' regrouping algorithm is to find a best solution by removing redundant groups within the existing solution from incremental group optimization. Since the existing...

    Provided By University of Wisconsin-Madison

  • White Papers // Dec 2010

    Calvin: Deterministic or Not? Free Will to Choose

    Most shared memory systems maximize performance by unpredictably resolving memory races. Unpredictable memory races can lead to non-determinism in parallel programs, which can suffer from hard-to-reproduce hiesenbugs. The authors introduce Calvin, a shared memory model capable of executing in a conventional nondeterministic mode when performance is paramount and a deterministic...

    Provided By University of Wisconsin-Madison

  • White Papers // Dec 2010

    Safe and Efficient Supervised Memory Systems

    Supervised Memory systems use out-of-band metabits to control and monitor accesses to normal data memory for such purposes as transactional memory and memory type state trackers. Previous proposals demonstrate the value of supervised memory systems, but have typically assumed sequential consistency (while most deployed systems use weaker models), and used...

    Provided By University of Wisconsin-Madison

  • White Papers // Nov 2010

    Inflation Persistence, Price Indexation And Optimal Simple Interest Rate Rules

    The authors study the properties of the optimal nominal interest rate policy under different levels of price indexation. In the model indexation regulates the sources of inflation persistence. When indexation is zero, the inflation gap is purely forward-looking and inflation persistence depends only on the level of trend inflation, while...

    Provided By University of Wisconsin-Madison

  • White Papers // Oct 2010

    Training, Search And Wage Dispersion Technical Appendix

    This paper combines on-the-job search and human capital theory to study the coexistence of firm-funded general training and frequent job turnovers. Although ex ante identical, firms differ in their training decisions. The model generates correlations between various firm characteristics that are consistent with the data. Wage dispersion exists among ex...

    Provided By University of Wisconsin-Madison

  • White Papers // Jul 2010

    Scalable WiFi Media Delivery Through Adaptive Broadcasts

    Current WiFi Access Points (APs) choose transmission parameters when emitting wireless packets based solely on channel conditions. In this work the authors explore the benefits of deciding packet transmission parameters in a content-dependent manner. They demonstrate the benefits specifically for media delivery applications in WiFi environments by designing, implementing and...

    Provided By University of Wisconsin-Madison

  • White Papers // Jul 2010

    Explaining Export Varieties: The Role Of Comparative Advantage

    This paper examines how factor proportions determine product varieties, or the extensive margin, in exports of countries. A model of the economy with two countries, two factors, and a multitude of industries with productivity-heterogeneous firms explains the relative number of export varieties in each country. A quasi-Heckscher-Ohlin prediction on export...

    Provided By University of Wisconsin-Madison

  • White Papers // Jun 2010

    MadCache: A PC-Aware Cache Insertion Policy

    While the field of computer architecture is always looking for novel research directions to bring improved performance and efficiency, it is often simple improvements to more mature topics that have the most substantial impact. Cache replacement policy is one such research area, where innovations are highly sought after because of...

    Provided By University of Wisconsin-Madison

  • White Papers // May 2010

    A First Look at Problems in the Cloud

    Cloud computing provides a revolutionary model for the deployment of enterprise applications and Web services alike. In this new model, cloud users save on the cost of purchasing and managing base infrastructure, while the cloud providers save on the cost of maintaining underutilized CPU, memory, and network resources. In migrating...

    Provided By University of Wisconsin-Madison

  • White Papers // Apr 2010

    Get the Parallelism Out of My Cloud

    The hardware trend toward multicore processors has so far been driven by technology limitations of wire delays, power efficiency, and limited capability to exploit instruction-level parallelism. Software evolution has lead to the rise of the cloud. This multicore + cloud evolution provides several challenges and has led to a call...

    Provided By University of Wisconsin-Madison

  • White Papers // Jan 2010

    Compressed Channel Sensing: A New Approach to Estimating Sparse Multipath Channels

    High-rate data communication over a multipath wireless channel often requires that the channel response be known at the receiver. Training-based methods, which probe the channel in time, frequency, and space with known signals and reconstruct the channel response from the output signals, are most commonly used to accomplish this task....

    Provided By University of Wisconsin-Madison

  • White Papers // Jan 2010

    Turning Cluster Management Into Data Management: A System Overview

    This paper introduces the CondorJ2 cluster management system. Traditionally, cluster management systems such as Condor employ a process-oriented approach with little or no use of modern database system technology. In contrast, CondorJ2 employs a data-centric, 3-tier web-application architecture for all system functions (e.g., job submission, monitoring and scheduling; node configuration,...

    Provided By University of Wisconsin-Madison

  • White Papers // Jan 2010

    Eliminating Handoff Latencies in 802.11 WLANs Using Multiple Radios: Applications, Experience, and Evaluation

    Deployment of Voice-over IP (VoIP) and other real-time streaming applications has been somewhat limited in wireless LANs today, partially because of the high handoff latencies experienced by mobile users. The goal in this work is to eliminate handoff latency by exploiting the potential of multiple radios in WLAN devices. The...

    Provided By University of Wisconsin-Madison

  • White Papers // Jan 2010

    Pro Ling Grid Data Transfer Protocols and Servers

    The trend of data intensive grid applications has brought grid storage protocols and servers into focus. The objective of this study is to gain an understanding of how time is spent in the storage protocols and servers. The storage protocols have a variety of tuning parameters. Some parameters improve single...

    Provided By University of Wisconsin-Madison

  • White Papers // Jan 2010

    Network-Level QoS Assurances Through Adaptive Allocation of CDMA Resources

    In a Code Division Multiple Access (CDMA) network, multiple Mobile Hosts (MHs) can simultaneously transmit over the wireless channel by using different codes. To assure an acceptable Quality of Service (QoS) for all MHs' flows, the network usually tunes the transmit powers of all MHs to achieve a certain level...

    Provided By University of Wisconsin-Madison

  • White Papers // Jan 2010

    Multiscalar Processors

    Multiscalar processors use a new, aggressive implementation paradigm for extracting large quantities of instruction level parallelism from ordinary high level language programs. A single program is divided into a collection of tasks by a combination of software and hardware. The tasks are distributed to a number of parallel processing units...

    Provided By University of Wisconsin-Madison

  • White Papers // Jan 2010

    MobiStream: Error-Resilient Video Streaming in Wireless WANs Using Virtual Channels

    This paper presents MobiStream - a video streaming system that exploits the perceptual value in video content and the characteristics of the link layer and physical layer channels to enable error-resilient video streaming over Wireless Wide-Area Networks (WWANs). The key building block in MobiStream is the use of link-layer based,...

    Provided By University of Wisconsin-Madison

  • White Papers // Dec 2009

    Leveraging Progress in Neurobiology for Computing Systems

    Whether future technologies will be ultra-small CMOS transistors, nanotubes, or even individual molecules or biological cells, these elementary components all share several common properties: they will be available in great numbers, they will not be much faster or may even be slower than current transistors, they may be hard to...

    Provided By University of Wisconsin-Madison

  • White Papers // Oct 2009

    Power Awareness in Network Design and Routing

    Increased scaling of bandwidth has been a prime driving force behind the growth and popularity of Internet. However, increase in various bandwidths has led to greater power consumption. Several sustained design efforts have been made to address power needs but significant technological challenges continue to exist and threaten the future...

    Provided By University of Wisconsin-Madison

  • White Papers // Oct 2009

    Building and Testing a Production Quality Grid Software Distribution for Open Science Grid

    The authors describe how the authors integrate, build, and test the Open Science Grid (OSG) software stack, which is used to provide a production quality infrastructure for grid sites and users across OSG to run their grid jobs. The software stack is sufficiently complex that building and testing the software...

    Provided By University of Wisconsin-Madison

  • White Papers // Oct 2009

    Leadership And Reform: Mapping The Causal Pathways Of Performance Information Use

    This paper offers empirical evidence on a specific question: how does leadership foster the use of performance data? More broadly, it informs the ways in which the people understand how leadership can influence the implementation of management reforms. Previous research suggests that leadership matters to performance information use among their...

    Provided By University of Wisconsin-Madison

  • White Papers // Sep 2009

    StealthTest: Low Overhead Online Software Testing Using Transactional Memory

    Software testing is hard. The emergence of multicore architectures and the proliferation of bug-prone multithreaded software makes testing even harder. To this end, researchers have proposed methods to continue testing software after deployment, e.g., In Vivo (IV) testing and Delta Execution (DE) patch testing. These on-line techniques typically fork new...

    Provided By University of Wisconsin-Madison

  • White Papers // Jan 2011

    Selectivity Estimation for XML Twigs

    Twig queries represent the building blocks of declarative query languages over XML data. A twig query describes a complex traversal of the document graph and generates a set of element tuples based on the intertwined evaluation (i.e., join) of multiple path expressions. Estimating the result cardinality of twig queries or,...

    Provided By University of Wisconsin-Madison

  • White Papers // Nov 2010

    Inflation Persistence, Price Indexation And Optimal Simple Interest Rate Rules

    The authors study the properties of the optimal nominal interest rate policy under different levels of price indexation. In the model indexation regulates the sources of inflation persistence. When indexation is zero, the inflation gap is purely forward-looking and inflation persistence depends only on the level of trend inflation, while...

    Provided By University of Wisconsin-Madison

  • White Papers // Oct 2009

    Leadership And Reform: Mapping The Causal Pathways Of Performance Information Use

    This paper offers empirical evidence on a specific question: how does leadership foster the use of performance data? More broadly, it informs the ways in which the people understand how leadership can influence the implementation of management reforms. Previous research suggests that leadership matters to performance information use among their...

    Provided By University of Wisconsin-Madison

  • White Papers // Jan 2009

    How Does Finance Affect Growth? Evidence From A Natural Experiment In Venezuela

    This paper examines the relation between financial development and economic growth by looking at plant-level evidence. The author argues that by focusing on a largely exogenous event, the implementation of exchange controls in Venezuela in 1983, this approach avoids many of the challenges facing the literature. Most importantly this quasi-experimental...

    Provided By University of Wisconsin-Madison

  • White Papers // Jan 2011

    A Comparative Study of Handheld and Non-Handheld Traffic in Campus Wi-Fi Networks

    Handheld devices such as smartphones have become a major platform for accessing Internet services. The small, mobile nature of these devices results in a unique mix of network usage. Other studies have used Wi-Fi and 3G wireless traces to analyze session, mobility, and performance characteristics for handheld devices. The authors...

    Provided By University of Wisconsin-Madison

  • White Papers // Sep 2011

    On Some Sufficient Conditions for Distributed QoS 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 complexity. The...

    Provided By University of Wisconsin-Madison

  • White Papers // Apr 2011

    The Best of Both Worlds With On-Demand Virtualization

    Virtualization offers many benefits such as live migration, resource consolidation, and checkpointing. However, there are many cases where the overhead of virtualization is too high to justify for its merits. Most desktop and laptop PCs and many large web properties run natively because the benefits of virtualization are too small...

    Provided By University of Wisconsin-Madison

  • White Papers // Jul 2011

    Exploiting Route Diversity in Multi-Packet Transmission Using Mutual Information Accumulation

    The authors consider cooperative communication in a given network using rateless codes. Given a network, a source and a destination, they investigate routing and resource allocation for delivering multiple packets through the network. They propose and design a centralized algorithm which minimizes a given objective under different network resource constraints....

    Provided By University of Wisconsin-Madison

  • White Papers // Jan 2010

    Compressed Channel Sensing: A New Approach to Estimating Sparse Multipath Channels

    High-rate data communication over a multipath wireless channel often requires that the channel response be known at the receiver. Training-based methods, which probe the channel in time, frequency, and space with known signals and reconstruct the channel response from the output signals, are most commonly used to accomplish this task....

    Provided By University of Wisconsin-Madison

  • White Papers // Jan 2012

    DiskRouter: A Flexible Infrastructure for High Performance Large Scale Data Transfers

    The steady increase in data sets of scientific applications, the trend towards collaborative research and the emergence of grid computing has created a need to move large quantities of data over wide-area networks. The dynamic nature of network makes it difficult to tune data transfer protocols to use the full...

    Provided By University of Wisconsin-Madison

  • White Papers // Nov 2011

    Multi-Instance Security and Its Application to Password-Based Cryptography

    This paper develops a theory of multi-instance (mi) security and applies it to provide the first proof-based support for the classical practice of salting in password-based cryptography. Mi-security comes into play in settings (like password-based cryptography) where it is computationally feasible to compromise a single instance (si), and provides a...

    Provided By University of Wisconsin-Madison

  • White Papers // May 2009

    On the Accuracy of TCP Throughput Prediction for Opportunistic Wireless Networks

    The increasing density of WiFi Access Points (APs) in metropolitan areas is enabling an opportunistic model of wireless networking, whereby a "Guest" user within range of one or more wireless APs can gain temporary Internet access through these APs. This paper addresses the problem of TCP throughput prediction for opportunistic...

    Provided By University of Wisconsin-Madison

  • White Papers // Dec 2008

    Towards Eco-Friendly Database Management Systems

    Database Management Systems (DBMSs) have largely ignored the task of managing the energy consumed during query processing. Both economical and environmental factors now require that DBMSs pay close attention to energy consumption. This paper approaches this issue by considering energy consumption as a first-class performance goal for query processing in...

    Provided By University of Wisconsin-Madison

  • White Papers // Dec 2008

    An Empirical Study of Malware Evolution

    The diversity, sophistication and availability of malicious software (malcode/malware) pose enormous challenges for securing networks and end hosts from attacks. This paper analyzes a large corpus of malcode meta data compiled over a period of 19 years. The aim is to understand how malcode has evolved over the years, and...

    Provided By University of Wisconsin-Madison

  • White Papers // Apr 2009

    Enhancing the Reliability of TCP With Network Coding

    Reliable transport protocols such as TCP are tuned to perform well in traditional networks where packet losses occur mostly because of congestion. However, networks with wireless and other lossy links also suffer from significant non-congestion related losses due to reasons such as bit errors, fading and handoffs. TCP responds to...

    Provided By University of Wisconsin-Madison

  • White Papers // Jul 2009

    Router-Level Spam Filtering Using TCP Fingerprints: Architecture and Measurement-Based Evaluation

    Email spam has become costly and difficult to manage in recent years. Many of the mechanisms used for controlling spam are located at local SMTP servers and end-host machines. These mechanisms can place a significant burden on mail servers and end-host machines as the number spam messages received continues to...

    Provided By University of Wisconsin-Madison

  • White Papers // Jul 2009

    RouterLevel Spam Filtering Using TCP Fingerprints: Architecture and Measurement-Based Evaluation

    Email spam has become costly and difficult to manage in recent years. Many of the mechanisms used for controlling spam are located at local SMTP servers and end-host machines. These mechanisms can place a significant burden on mail servers and end-host machines as the number spam messages received continues to...

    Provided By University of Wisconsin-Madison

  • White Papers // Oct 2009

    Power Awareness in Network Design and Routing

    Increased scaling of bandwidth has been a prime driving force behind the growth and popularity of Internet. However, increase in various bandwidths has led to greater power consumption. Several sustained design efforts have been made to address power needs but significant technological challenges continue to exist and threaten the future...

    Provided By University of Wisconsin-Madison

  • White Papers // Jan 2010

    Eliminating Handoff Latencies in 802.11 WLANs Using Multiple Radios: Applications, Experience, and Evaluation

    Deployment of Voice-over IP (VoIP) and other real-time streaming applications has been somewhat limited in wireless LANs today, partially because of the high handoff latencies experienced by mobile users. The goal in this work is to eliminate handoff latency by exploiting the potential of multiple radios in WLAN devices. The...

    Provided By University of Wisconsin-Madison

  • White Papers // Jan 2010

    Turning Cluster Management Into Data Management: A System Overview

    This paper introduces the CondorJ2 cluster management system. Traditionally, cluster management systems such as Condor employ a process-oriented approach with little or no use of modern database system technology. In contrast, CondorJ2 employs a data-centric, 3-tier web-application architecture for all system functions (e.g., job submission, monitoring and scheduling; node configuration,...

    Provided By University of Wisconsin-Madison

  • White Papers // Apr 2010

    Get the Parallelism Out of My Cloud

    The hardware trend toward multicore processors has so far been driven by technology limitations of wire delays, power efficiency, and limited capability to exploit instruction-level parallelism. Software evolution has lead to the rise of the cloud. This multicore + cloud evolution provides several challenges and has led to a call...

    Provided By University of Wisconsin-Madison

  • White Papers // Jan 2010

    Pro Ling Grid Data Transfer Protocols and Servers

    The trend of data intensive grid applications has brought grid storage protocols and servers into focus. The objective of this study is to gain an understanding of how time is spent in the storage protocols and servers. The storage protocols have a variety of tuning parameters. Some parameters improve single...

    Provided By University of Wisconsin-Madison

  • White Papers // Jan 2010

    Network-Level QoS Assurances Through Adaptive Allocation of CDMA Resources

    In a Code Division Multiple Access (CDMA) network, multiple Mobile Hosts (MHs) can simultaneously transmit over the wireless channel by using different codes. To assure an acceptable Quality of Service (QoS) for all MHs' flows, the network usually tunes the transmit powers of all MHs to achieve a certain level...

    Provided By University of Wisconsin-Madison

  • White Papers // Dec 2004

    Learning By Design: Good Video Games As Learning Machines

    Many good computer and video games, games like Deus Ex, The Elder Scrolls III: Morrowind, or Rise of Nations, are long, complex, and difficult, especially for beginners [from now on I will simply use the term "Video games" for both computer games and games on platforms like the Playstation 2,...

    Provided By University of Wisconsin-Madison

  • White Papers // Feb 2009

    Condition Variables and Transactional Memory: Problem or Opportunity?

    Condition variables complement locks by allowing a program to specify the order of execution. They have been in use, largely unchanged, for three decades and have proved to be a robust and scalable synchronization mechanism. However, most Transactional Memory (TM) systems provide no complementary mechanism. While new synchronization constructs have...

    Provided By University of Wisconsin-Madison

  • White Papers // Dec 2010

    Safe and Efficient Supervised Memory Systems

    Supervised Memory systems use out-of-band metabits to control and monitor accesses to normal data memory for such purposes as transactional memory and memory type state trackers. Previous proposals demonstrate the value of supervised memory systems, but have typically assumed sequential consistency (while most deployed systems use weaker models), and used...

    Provided By University of Wisconsin-Madison

  • White Papers // Dec 2010

    Calvin: Deterministic or Not? Free Will to Choose

    Most shared memory systems maximize performance by unpredictably resolving memory races. Unpredictable memory races can lead to non-determinism in parallel programs, which can suffer from hard-to-reproduce hiesenbugs. The authors introduce Calvin, a shared memory model capable of executing in a conventional nondeterministic mode when performance is paramount and a deterministic...

    Provided By University of Wisconsin-Madison

  • White Papers // Jan 2011

    A Framework for Reliable and Efficient Data Placement in Distributed Computing Systems

    Data placement is an essential part of today's distributed applications since moving the data close to the application has many benefits. The increasing data requirements of both scientific and commercial applications and collaborative access to these data make it even more important. In the current approach, data placement is regarded...

    Provided By University of Wisconsin-Madison

  • White Papers // Jan 2011

    Profiling Heterogeneous Multi-GPU Systems to Accelerate Cortically Inspired Learning Algorithms

    Recent advances in neuroscientific understanding make parallel computing devices modeled after the human neocortex a plausible, attractive, fault-tolerant, and energy efficient possibility. Such attributes have once again sparked an interest in creating learning algorithms that aspire to reverse engineer many of the abilities of the brain. In this paper the...

    Provided By University of Wisconsin-Madison

  • White Papers // Jan 2009

    The Case for a Structured Approach to Managing Unstructured Data

    The challenge of managing unstructured data represents per-haps the largest data management opportunity for the community since managing relational data. And yet the authors are risking letting this opportunity go by, ceding the playing field to other players, ranging from communities such as AI, KDD, IR, Web, and Semantic Web,...

    Provided By University of Wisconsin-Madison

  • White Papers // Dec 2008

    Information Extraction Challenges in Managing Unstructured Data

    Over the past few years, the authors have been trying to build an end-to-end system at Wisconsin to manage unstructured data, using extraction, integration, and user interaction. This paper describes the key Information Extraction (IE) challenges that they have run into, and sketches the solutions. The authors discuss in particular...

    Provided By University of Wisconsin-Madison

  • White Papers // Jun 2010

    MadCache: A PC-Aware Cache Insertion Policy

    While the field of computer architecture is always looking for novel research directions to bring improved performance and efficiency, it is often simple improvements to more mature topics that have the most substantial impact. Cache replacement policy is one such research area, where innovations are highly sought after because of...

    Provided By University of Wisconsin-Madison

  • White Papers // Dec 2009

    Leveraging Progress in Neurobiology for Computing Systems

    Whether future technologies will be ultra-small CMOS transistors, nanotubes, or even individual molecules or biological cells, these elementary components all share several common properties: they will be available in great numbers, they will not be much faster or may even be slower than current transistors, they may be hard to...

    Provided By University of Wisconsin-Madison

  • White Papers // Jan 2011

    Cortical Columns: Building Blocks for Intelligent Systems

    The neocortex appears to be a very efficient, uniformly structured, and hierarchical computational system. Researchers have made significant efforts to model intelligent systems that mimic these neocortical properties to perform a broad variety of pattern recognition and learning tasks. Unfortunately, many of these systems have drifted away from their cortical...

    Provided By University of Wisconsin-Madison

  • White Papers // Oct 2010

    Training, Search And Wage Dispersion Technical Appendix

    This paper combines on-the-job search and human capital theory to study the coexistence of firm-funded general training and frequent job turnovers. Although ex ante identical, firms differ in their training decisions. The model generates correlations between various firm characteristics that are consistent with the data. Wage dispersion exists among ex...

    Provided By University of Wisconsin-Madison

  • White Papers // Jan 2011

    NiagaraCQ: A Scalable Continuous Query System for Internet Databases

    Continuous queries are persistent queries that allow users to receive new results when they become available. While continuous query systems can transform a passive web into an active environment, they need to be able to support millions of queries due to the scale of the Internet. No existing systems have...

    Provided By University of Wisconsin-Madison

  • White Papers // Jan 2011

    Form-Based Proxy Caching for Database-Backed Web Sites

    The authors explore a new proxy-caching framework that exploits the query semantics of HTML forms. They identify a common class of form-based queries, and study two representative caching schemes for them within this framework: traditional passive query caching, and active query caching, in which the proxy cache can service a...

    Provided By University of Wisconsin-Madison

  • White Papers // Jan 2011

    IDB: Toward the Scalable Integration of Queryable Internet Data Sources

    As the number of databases accessible on the Web grows, the ability to execute queries spanning multiple heterogeneous queryable sources is becoming increasingly important. To date, research in this area has focused on providing semantic completeness, and has generated solutions that work well when querying over a relatively small number...

    Provided By University of Wisconsin-Madison

  • White Papers // Jan 2011

    A Case for Fractured Mirrors

    The Decomposition Storage Model (DSM) vertically partitions all attributes of a given relation. DSM has excellent I/O behavior when the number of attributes touched in the query is small. It also has a better cache footprint than the N-ary Storage Model (NSM) that is used by most database systems. However,...

    Provided By University of Wisconsin-Madison

  • White Papers // Jan 2011

    Improved Histograms for Selectivity Estimation of Range Predicates

    Many commercial database systems maintain histograms to summarize the contents of relations and permit efficient estimation of query result sizes and access plan costs. Although several types of histograms have been proposed in the past, there has never been a systematic study of all histogram aspects, the available choices for...

    Provided By University of Wisconsin-Madison