University of Virginia

Displaying 1-40 of 103 results

  • White Papers // May 2012

    A Model and Decision Procedure for Data Storage in Cloud Computing

    Cloud computing offers many possibilities for prospective users; there are however many different storage and compute services to choose from between all the cloud providers and their multiple datacenters. In this paper, the authors focus on the problem of selecting the best storage services according to the application's requirements and...

    Provided By University of Virginia

  • White Papers // Mar 2012

    A Systematic Study of Automated Program Repair: Fixing 55 Out of 105 Bugs for $8 Each

    There are more bugs in real-world programs than human programmers can realistically address. This paper evaluates two research questions: "What fraction of bugs can be repaired automatically?" and "How much does it cost to repair a bug automatically?" In previous work, the authors presented GenProg, which uses genetic programming to...

    Provided By University of Virginia

  • White Papers // Mar 2012

    Synthesizing API Usage Examples

    Key program interfaces are sometimes documented with usage examples: concrete code snippets that characterize common use cases for a particular data type. While such documentation is known to be of great utility, it is burdensome to create and can be incomplete, out of date, or not representative of actual practice....

    Provided By University of Virginia

  • White Papers // Dec 2011

    Assessing the Value of Cloudbursting: A Case Study of Satellite Image Processing on Windows Azure

    To perform computational experiments at greater scale and in less time, enterprises are increasingly looking to dynamically expand their computing capabilities through the temporary addition of cloud resources (aka "Cloud-bursting"). Computational infrastructure can be dismantled in minutes with no long-term capital investments. However, research is needed to identify which properties...

    Provided By University of Virginia

  • White Papers // Jun 2011

    GuardRails: A Data-Centric Web Application Security Framework

    Modern web application frameworks have made it easy to create powerful web applications. Developing a secure web application, however, still requires a developer to posses a deep understanding of security vulnerabilities and attacks. Even for experienced developers it is tedious, if not impossible, to find and eliminate all vulnerabilities. This...

    Provided By University of Virginia

  • White Papers // Jun 2011

    Kicking The Dog: Korea's Bureaucratic Resistance To Globalization In Reaction To Democratization

    Seven years have passed since the Korean economy was engulfed by the 1997 Asian Financial Crisis. Arguably, the country is still not fully recovered from the catastrophe almost a decade later. In those intervening years, numerous books and papers have attempted to diagnose the origins of the extraordinarily sharp downturn...

    Provided By University of Virginia

  • White Papers // May 2011

    Private Editing Using Untrusted Cloud Services

    The authors present a general methodology for protecting the confidentiality and integrity of user data for a class of on-line editing applications. The key insight is that many of these applications are designed to perform most of their data-dependent computation on the client side, so it is possible to maintain...

    Provided By University of Virginia

  • White Papers // Apr 2011

    Feasibility of Dynamic Binary Parallelization

    This paper proposes DBP, an automatic technique that transparently parallelizes a sequential binary executable while it is running. A prototype implementation in simulation was able to increase sequential execution speeds by up to 1.96x, averaged over three benchmarks suites. Fundamental issues in microprocessor technologies have led designers to increase the...

    Provided By University of Virginia

  • White Papers // Apr 2011

    Interest Rates And Inflation

    For some time now the author have been intrigued by the apparent relationship between the behavior of various interest rates and that of inflation. As a physicist, the author views economics the same way the author views physical systems. Namely, describe them by a model which is amenable to mathematical...

    Provided By University of Virginia

  • White Papers // Mar 2011

    An Analysis of Using High-Frequency Sinusoidal Illumination to Measure the 3D Shape of Translucent Objects

    Using optical triangulation methods to measure the shape of translucent objects is difficult because subsurface scattering contaminates measurements of the "Direct" reflection at the surface. A number of recent papers have shown that high-frequency sinusoidal illumination patterns allow isolating this direct component, which in turn enables accurate estimation of the...

    Provided By University of Virginia

  • White Papers // Mar 2011

    Extending SAT Solvers to Cryptographic Problems

    Cryptography ensures the con confidentiality and authenticity of information but often relies on unproven assumptions. SAT solvers are a powerful tool to test the hardness of certain problems and have successfully been used to test hardness assumptions. This paper extends a SAT solver to efficiently work on cryptographic problems. The...

    Provided By University of Virginia

  • White Papers // Feb 2011

    Where Is the Data? Why You Cannot Debate CPU Vs. GPU Performance Without the Answer

    General Purpose GPU Computing (GPGPU) has taken off in the past few years, with great promises for increased desktop processing power due to the large number of fast computing cores on high-end graphics cards. Many publications have demonstrated phenomenal performance and have reported speedups as much as 1000x over code...

    Provided By University of Virginia

  • White Papers // Feb 2011

    Improving Region Selection Through Loop Completion

    Dynamic binary translation is a powerful technique for program analysis and modification that operates on binary code as it executes, thus availing itself of information only available at run-time. However, by intervening between the software and hardware, a significant slowdown may be introduced into program execution, which can hinder widespread...

    Provided By University of Virginia

  • White Papers // Feb 2011

    Improving Indirect Branch Translation in Dynamic Binary Translators

    Dynamic Binary Translators (DBTs) have a wide range of applications including program instrumentation, dynamic optimization, and security. One of the main issues with DBTs is their performance overhead. A significant part of this overhead is caused by Indirect Branch (IB) translation. In this paper, the authors show that the percentage...

    Provided By University of Virginia

  • White Papers // Feb 2011

    Distributed Uplink Resource Allocation in Cognitive Radio Networks - Part II: Equilibria and Algorithms for Joint Access Point Selection and Power Allocation

    The main objective of this two part paper is to formulate and address the problem of distributed uplink resource allocation in multi-carrier Cognitive Radio Networks (CRN) with multiple Access Points (APs). When the APs operate on non-overlapping spectrum bands, such problem is essentially a joint spectrum decision and spectrum sharing...

    Provided By University of Virginia

  • White Papers // Feb 2011

    Joint Distributed Access Point Selection and Power Allocation in Cognitive Radio Networks

    Spectrum management has been identified as a crucial step towards enabling the technology of the Cognitive Radio Network (CRN). Most of the current works dealing with spectrum management in the CRN focus on a single task of the problem, e.g., spectrum sensing, spectrum decision, spectrum sharing or spectrum mobility. In...

    Provided By University of Virginia

  • White Papers // Feb 2011

    Efficient Privacy-Preserving Biometric Identification

    The authors present an efficient matching protocol that can be used in many privacy-preserving biometric identification systems in the semi-honest setting. The most general technical contribution is a new backtracking protocol that uses the byproduct of evaluating a garbled circuit to enable efficient oblivious information retrieval. They also present a...

    Provided By University of Virginia

  • White Papers // Feb 2011

    A Sub-0.5V Lattice-Based Public-Key Encryption Scheme for RFID Platforms in 130nm CMOS

    Implementing public-key cryptography on passive RFID tags is very challenging due to the limited die size and power available. Typical public-key algorithms require complex logical components such as modular exponentiation in RSA. The authors demonstrate the feasibility of implementing public-key encryption on low-power, low cost passive RFID tags to large-scale...

    Provided By University of Virginia

  • White Papers // Jan 2011

    Bandwidth Allocation in Hexagonal Wireless Sensor Networks for Real-Time Communications

    This paper presents an algorithm for bandwidth allocation for delay-sensitive traffic in multi-hop wireless sensor networks. The solution considers both periodic as well as a periodic real-time traffic in an unified manner. The authors also present a distributed MAC protocol that conforms to the bandwidth allocation and thus satisfies the...

    Provided By University of Virginia

  • White Papers // Jan 2011

    Heterogeneous Chip Multiprocessor Design for Virtual Machines

    Multi-core architectures provide an alternative to increasing clock frequencies to improve performance of modern processors. The best design for these chip multiprocessors, including structure sizes or whether to use homogeneous or heterogeneous cores, remains open for exploration. One potential design path involves using heterogeneous cores that are specialized for a...

    Provided By University of Virginia

  • White Papers // Jan 2011

    Enviro-Track: Towards an Environmental Computing Paradigm for Distributed Sensor Networks

    Distributed sensor networks are quickly gaining recognition as viable embedded computing platforms. Current techniques for programming sensor networks are cumbersome, inflexible, and low-level. This paper introduces EnviroTrack, an object-based distributed middleware system that raises the level of programming abstraction by providing a convenient and powerful interface to the application developer...

    Provided By University of Virginia

  • White Papers // Jan 2011

    CMP Design Space Exploration Subject to Physical Constraints

    This paper explores the multi-dimensional design space for chip multiprocessors, exploring the inter-related variables of core count, pipeline depth, superscalar width, L2 cache size, and operating voltage and frequency, under various area and thermal constraints. The results show the importance of joint optimization. Thermal constraints dominate other physical constraints such...

    Provided By University of Virginia

  • White Papers // Jan 2011

    A Performance Study of General Purpose Applications on Graphics Processors

    Graphic Processors Unit (GPUs), with many light-weight data-parallel cores, can provide substantial parallel computational power to accelerate general purpose applications. To best utilize the GPU's parallel computing resources, it is crucial to understand how GPU architectures and programming models can be applied to different categories of traditionally CPU applications. In...

    Provided By University of Virginia

  • White Papers // Jan 2011

    Accelerating Compute-Intensive Applications With GPUs and FPGAs

    Accelerators are special purpose processors designed to speed up compute-intensive sections of applications. Two extreme endpoints in the spectrum of possible accelerators are FPGAs and GPUs, which can often achieve better performance than CPUs on certain workloads. FPGAs are highly customizable, while GPUs provide massive parallel execution resources and high...

    Provided By University of Virginia

  • White Papers // Jan 2011

    Thunder: Towards Practical, Zero Cost Acoustic Localization for Outdoor Wireless Sensor Networks

    Localization for outdoor wireless sensor networks has been a challenge for real applications. Although many solutions have been proposed, few of them can be used in real applications because of their high cost, low accuracy or infeasibility due to practical issues. In this paper, the authors propose a practical acoustic...

    Provided By University of Virginia

  • White Papers // Jan 2011

    An Entity Maintenance and Connection Service for Sensor Networks

    In this paper, the authors present a middleware architecture for coordination services in sensor networks that facilitates interaction between groups of sensors which monitor different environmental events. It sits on top of the native routing infrastructure and exports the abstraction of mobile communication endpoints maintained at the locations of such...

    Provided By University of Virginia

  • White Papers // Jan 2011

    A Communication Architecture and Programming Abstractions for Real-Time Embedded Sensor Networks

    Data distribution in embedded real-time sensor networks requires new protocols and programming environments that achieve time-sensitive message delivery and provide useful abstractions to the application programmer. Attainment of these goals requires changes to multiple layers of the communication protocol stack. In this paper, the authors review a protocol suite developed...

    Provided By University of Virginia

  • White Papers // Dec 2010

    Modeling and Analyzing NBTI in the Presence of Process Variation

    With continuous scaling of transistors in each technology generation, NBTI and Process Variation (PV) have become very important silicon reliability problems for the microprocessor industry. In this paper, the authors develop an analytical model to capture the impact of NBTI in the presence of PV for use in architecture simulations....

    Provided By University of Virginia

  • White Papers // Dec 2010

    Looking For Local-Labor-Market Effects Of NAFTA

    Using US Census data for 1990 and 2000, the authors estimate effects of the NAFTA agreement on the US wages. They look for any indication of effects of the agreement on the local labor markets dependent on industries vulnerable to import competition from Mexico, and the workers employed in industries...

    Provided By University of Virginia

  • White Papers // Dec 2010

    Looking For Local Labor-Market Effects Of The NAFTA

    Using US Census data for 1990 and 2000, the authors estimate effects of the NAFTA agreement on the US wages. They look for any indication of effects of the agreement on local labor markets dependent on industries vulnerable to import competition from Mexico, and workers employed in industries competing with...

    Provided By University of Virginia

  • White Papers // Dec 2010

    Applicability of the Willow Architecture for Cloud Management

    The differences between grids and clouds arguably include objectives, organization, scale, and workload. By examining these fundamental characteristics and requirements in detail, the authors assess the degree to which a generic management infrastructure for grid computing can be applied to cloud infrastructures. The analysis is further refined by considering a...

    Provided By University of Virginia

  • White Papers // Dec 2010

    Relaxing Non-Volatility for Fast and Energy-Efficient STT-RAM Caches

    Spin-Transfer Torque RAM (STT-RAM) is an emerging non-volatile memory technology that is a potential universal memory that could replace SRAM in processor caches. This paper presents a novel approach for redesigning STT-RAM memory cells to reduce the high dynamic energy and slow write latencies. The authors lower the retention time...

    Provided By University of Virginia

  • White Papers // Dec 2010

    Fault Tolerance and Scaling in e-Science Cloud Applications: Observations From the Continuing Development of MODISAzure

    It can be natural to believe that many of the traditional issues of scale have been eliminated or at least greatly reduced via cloud computing. That is, if one can create a seemingly well-functioning cloud application that operates correctly on small or moderate-sized problems, then the very nature of cloud...

    Provided By University of Virginia

  • White Papers // Dec 2010

    CSAL: A Cloud Storage Abstraction Layer to Enable Portable Cloud Applications (work-in-Progress)

    One of the large impediments for adoption of cloud computing is perceived vendor lock-in with respect to both low-level resource management and application level storage services. Application portability is essential to both avoid lock-in as well as leverage the ever changing landscape of cloud offerings. The authors present a storage...

    Provided By University of Virginia

  • White Papers // Dec 2010

    Shouting To Be Heard In Advertising

    Advertising competes for consumer attention, but attention is scarce. More profitable senders send more messages to break through the clutter. There may be multiple equilibria: more messages in aggregate induce more "Shouting to be heard" among senders trying to break through the advertising clutter, which creates a "Lottery ticket" dimension...

    Provided By University of Virginia

  • White Papers // Oct 2010

    A Human Study of Fault Localization Accuracy

    Localizing and repairing defects are critical software engineering activities. Not all programs and not all bugs are equally easy to debug, however. They present formal models, backed by a human study involving 65 participants (from both academia and industry) and 1830 total judgments, relating various software- and defect-related features to...

    Provided By University of Virginia

  • White Papers // Oct 2010

    Economic Effects Of Health Care Reform On Virginia

    This paper estimates the impact of the 2010 health care reform law (the Patient Protection and Affordable Care Act/Health Care and Education Reconciliation Act) on Virginia's economy. Health care reform is a complex and multifaceted law that was enacted with the joint goals of improving health insurance coverage for U.S....

    Provided By University of Virginia

  • White Papers // Aug 2010

    University Of Virginia Equal Opportunity Report 2010

    The University of Virginia's 2010 Equal Opportunity Report contains information and data from the October 2008 to October 2009 reporting period that provides a broad range of undertakings and good faith efforts taken by schools and departments to ensure equal opportunity for faculty and staff. The units have increased their...

    Provided By University of Virginia

  • White Papers // Aug 2010

    U.S. International Equity Investment

    U.S. investors are the largest group of international equity investors in the world, but to date conclusive evidence on which types of foreign firms are able to attract U.S. investment is not available. Authors use a comprehensive dataset of all U.S. investment in all foreign equities to address this issue....

    Provided By University of Virginia

  • White Papers // Aug 2010

    Cloud Auto-Scaling With Deadline and Budget Constraints

    Clouds have become an attractive computing platform which offers on-demand computing power and storage capacity. Its dynamic scalability enables users to quickly scale up and scale down underlying infrastructure in response to business volume, performance desire and other dynamic behaviors. However, challenges arise when considering computing instance non-deterministic acquisition time,...

    Provided By University of Virginia

  • White Papers // Mar 2011

    Extending SAT Solvers to Cryptographic Problems

    Cryptography ensures the con confidentiality and authenticity of information but often relies on unproven assumptions. SAT solvers are a powerful tool to test the hardness of certain problems and have successfully been used to test hardness assumptions. This paper extends a SAT solver to efficiently work on cryptographic problems. The...

    Provided By University of Virginia

  • White Papers // Aug 2010

    Eliminating Voltage Emergencies Via Software-Guided Code Transformations

    In recent years, circuit reliability in modern high-performance processors has become increasingly important. Shrinking feature sizes and diminishing supply voltages have made circuits more sensitive to microprocessor supply voltage fluctuations. These fluctuations result from the natural variation of processor activity as workloads execute, but when left unattended, these voltage fluctuations...

    Provided By University of Virginia

  • White Papers // Dec 2009

    Protocols for Secure Multi-party Computation: Design, Implementation and Performance Evaluation

    Protocols for secure multi-party computation allow participants to share a computation while each party learns only what can be inferred from their own inputs and the output of the computation. However, the execution time of a secure protocol may be too high so that it is not practical unless some...

    Provided By University of Virginia

  • White Papers // Jan 2011

    Heterogeneous Chip Multiprocessor Design for Virtual Machines

    Multi-core architectures provide an alternative to increasing clock frequencies to improve performance of modern processors. The best design for these chip multiprocessors, including structure sizes or whether to use homogeneous or heterogeneous cores, remains open for exploration. One potential design path involves using heterogeneous cores that are specialized for a...

    Provided By University of Virginia

  • White Papers // May 2009

    Challenges and Opportunities at All Levels: Interactions Among Operating Systems, Compilers, and Multicore Processors

    The tremendous advances in process technology have opened the doors to many opportunities, but have also introduced a wealth of challenges. On one hand, microprocessor designers can pack several cores, whether homogeneous or heterogeneous, on a single chip, enabling more parallelism. On the other hand, programmers must focus on producing...

    Provided By University of Virginia

  • White Papers // May 2010

    Design of a Custom VEE Core in a Chip Multiprocessor

    Chip multiprocessors provide an opportunity for continuing performance growth in the face of limited single-thread parallelism. Although the best design path for such chips remains open, application-specific core designs have shown promise. This work considers the design of an application-specific core for a virtual execution environment. The authors use Pin,...

    Provided By University of Virginia

  • White Papers // Feb 2011

    Improving Region Selection Through Loop Completion

    Dynamic binary translation is a powerful technique for program analysis and modification that operates on binary code as it executes, thus availing itself of information only available at run-time. However, by intervening between the software and hardware, a significant slowdown may be introduced into program execution, which can hinder widespread...

    Provided By University of Virginia

  • White Papers // Feb 2011

    Improving Indirect Branch Translation in Dynamic Binary Translators

    Dynamic Binary Translators (DBTs) have a wide range of applications including program instrumentation, dynamic optimization, and security. One of the main issues with DBTs is their performance overhead. A significant part of this overhead is caused by Indirect Branch (IB) translation. In this paper, the authors show that the percentage...

    Provided By University of Virginia

  • White Papers // Jun 2009

    A Cross-Layer Approach to Heterogeneity and Reliability

    As modern hardware becomes increasingly complex, it becomes more difficult to create efficient software for common computing workloads. One way to manage this complexity is to employ holistic solutions that consider multiple layers of hardware and software in conjunction, allowing software to adapt and react to changing conditions at run...

    Provided By University of Virginia

  • White Papers // Feb 2011

    Where Is the Data? Why You Cannot Debate CPU Vs. GPU Performance Without the Answer

    General Purpose GPU Computing (GPGPU) has taken off in the past few years, with great promises for increased desktop processing power due to the large number of fast computing cores on high-end graphics cards. Many publications have demonstrated phenomenal performance and have reported speedups as much as 1000x over code...

    Provided By University of Virginia

  • White Papers // Aug 2010

    University Of Virginia Equal Opportunity Report 2010

    The University of Virginia's 2010 Equal Opportunity Report contains information and data from the October 2008 to October 2009 reporting period that provides a broad range of undertakings and good faith efforts taken by schools and departments to ensure equal opportunity for faculty and staff. The units have increased their...

    Provided By University of Virginia

  • White Papers // Jan 2010

    ControlWare: A Middleware Architecture for Feedback Control of Software Performance

    Attainment of software performance assurances in open, largely unpredictable environments has recently become an important focus for real-time research. Unlike closed embedded systems, many contemporary distributed real-time applications operate in environments where offered load and available resources suffer considerable random fluctuations, thereby complicating the performance assurance problem. Feedback control theory...

    Provided By University of Virginia

  • White Papers // Jan 2010

    Research Challenges for Wireless Sensor Networks

    Wireless Sensor Networks (WSN) are currently receiving significant attention due to their unlimited potential. However, it is still very early in the lifetime of such systems and many research challenges exist. In this paper, I concentrate on six key research challenges for wireless sensor networks. I conclude with a brief...

    Provided By University of Virginia

  • White Papers // Jan 2010

    ALARM-NET: Wireless Sensor Networks for Assisted-Living and Residential Monitoring

    This paper describes ALARM-NET, a wireless sensor network for assisted-living and residential monitoring. It integrates environmental and physiological sensors in a scalable, heterogeneous architecture. A query protocol allows real-time collection and processing of sensor data by user interfaces and back-end analysis programs. One such program determines circadian activity rhythms of...

    Provided By University of Virginia

  • White Papers // Apr 2009

    Fully Predictable HPC Infrastructure Using Admission Control With Virtualization

    Historically, batch scheduling has dominated in managing HPC workloads despite its unpredictability regarding job's wait time. Although existing researches such as reservation partially solved the problem, fully predictable HPC system still remains elusive goal while emerging adaptive applications urge its realization. The earlier study presented a control-theoretic, VM-based approach that...

    Provided By University of Virginia

  • White Papers // Dec 2010

    CSAL: A Cloud Storage Abstraction Layer to Enable Portable Cloud Applications (work-in-Progress)

    One of the large impediments for adoption of cloud computing is perceived vendor lock-in with respect to both low-level resource management and application level storage services. Application portability is essential to both avoid lock-in as well as leverage the ever changing landscape of cloud offerings. The authors present a storage...

    Provided By University of Virginia

  • White Papers // Apr 2010

    EScience in the Cloud: A MODIS Satellite Data Reprojection and Reduction Pipeline in the Windows Azure Platform

    The combination of low-cost sensors, low-cost commodity computing, and the Internet is enabling a new era of data-intensive science. The dramatic increase in this data availability has created a new challenge for scientists: how to process the data. Scientists today are envisioning scientific computations on large scale data but are...

    Provided By University of Virginia

  • White Papers // Aug 2010

    U.S. International Equity Investment

    U.S. investors are the largest group of international equity investors in the world, but to date conclusive evidence on which types of foreign firms are able to attract U.S. investment is not available. Authors use a comprehensive dataset of all U.S. investment in all foreign equities to address this issue....

    Provided By University of Virginia

  • White Papers // Mar 2010

    Automatically Exporting TinyOS Modules as Web Services

    As embedded devices become increasingly useful and ubiquitous, it will be important to incorporate them into enterprise applications through Web services and service-oriented architectures. Existing approaches have limitations in terms of either resource consumption or burden on the programmer. This paper presents a new framework to automatically export TinyOS modules...

    Provided By University of Virginia

  • White Papers // Feb 2010

    Using Height Sensors for Biometric Identification in Multi-Resident Homes

    In this paper the authors evaluate the use of height for biometric identification of residents, by mounting ultrasonic distance sensors above the doorways in a home. Height sensors are cheap, are convenient for the residents, are simple to install in an existing home, and are perceived to be less invasive...

    Provided By University of Virginia

  • White Papers // May 2010

    QueueTrak: Automated Line Length Detection Using a Wireless Sensor Network

    This paper describes QueueTrak, an automated wireless sensor system designed to detect and report the length of lines in retail environments. QueueTrak has two components. First, it uses a series of custom active infrared sensors to detect the length of a line in a store or restaurant. Second, a web...

    Provided By University of Virginia

  • White Papers // Apr 2010

    Melange: Supporting Heterogeneous QoS Requirements in Delay Tolerant Sensor Networks

    In sparse mobile sensor networks, nodes have a small number of neighbors with intermittent connectivity. This paper presents a new networking protocol for this type of network, aimed at maximizing system performance in terms of both delay and reliability. The system is motivated by the observation that many applications on...

    Provided By University of Virginia

  • White Papers // Dec 2009

    IAA: Interference Aware Anticipatory Algorithm for Scheduling and Routing Periodic Real-Time Streams in Wireless Sensor Networks

    This paper provides a polynomial time heuristic for the real-time communication scheduling problem in multi-hop wireless sensor networks. Wireless networks add a new dimension to the real-time communication problem because of interference: a transmission cannot be scheduled on a radio link if another transmission is scheduled on any interfering link....

    Provided By University of Virginia

  • White Papers // Dec 2010

    Looking For Local-Labor-Market Effects Of NAFTA

    Using US Census data for 1990 and 2000, the authors estimate effects of the NAFTA agreement on the US wages. They look for any indication of effects of the agreement on the local labor markets dependent on industries vulnerable to import competition from Mexico, and the workers employed in industries...

    Provided By University of Virginia

  • White Papers // Dec 2009

    Flashpower: A Detailed Power Model for Nand Flash Memory

    Flash memory is widely used in consumer electronics products, such as cell-phones and music players, and is increasingly displacing hard disk drives as the primary storage device in laptops, desktops, and even servers. There is a rich micro architectural design space for flash memory and there are several architectural options...

    Provided By University of Virginia

  • White Papers // Apr 2010

    Object Localization Using RFID

    Object localization is a key primitive in pervasive computing environments, where numerous applications depend on the rapid and accurate position estimation of objects. This paper presents a general RFID - based localization framework that reliably determines the positions of objects with unprecedented accuracy and speed. This is achieved by varying...

    Provided By University of Virginia

  • White Papers // Dec 2009

    On Mitigating Covert Channels in RFID-Enabled Supply Chains

    In a competitive business environment, RFID technology can help a business to optimize its supply chain. However, it may also enable an adversary using covert channels to surreptitiously learn sensitive information about the supply chain of a target business. The authors argue that the tracking of tags and the compromising...

    Provided By University of Virginia

  • White Papers // Jan 2011

    Bandwidth Allocation in Hexagonal Wireless Sensor Networks for Real-Time Communications

    This paper presents an algorithm for bandwidth allocation for delay-sensitive traffic in multi-hop wireless sensor networks. The solution considers both periodic as well as a periodic real-time traffic in an unified manner. The authors also present a distributed MAC protocol that conforms to the bandwidth allocation and thus satisfies the...

    Provided By University of Virginia

  • White Papers // Dec 2009

    ACR: Active Collision Recovery in Dense Wireless Sensor Networks

    Packet collision causes packet loss and wastes resources in wireless networks. It becomes even worse in dense WSNs, due to burst-traffic and congestion around sinks. In this paper, the authors propose a novel protocol to recover collided packets. The experiments on a testbed reveal that collisions between long packets and...

    Provided By University of Virginia

  • White Papers // Apr 2009

    Online Coding for Reliable Data Transfer in Lossy Wireless Sensor Networks

    Bulk transport underlies data exfiltration and code update facilities in WSNs, but existing approaches are not designed for highly lossy and variable-quality links. The authors observe that Maymounkov's rateless online codes are asymptotically more efficient, but can perform poorly in the WSN operating region. This paper analyzes and optimizes coding...

    Provided By University of Virginia

  • White Papers // Sep 2009

    Towards Stable Network Performance in Wireless Sensor Networks

    Many applications in wireless sensor networks require communication performance that is both consistent and high quality. Unfortunately, performance of current network protocols can vary significantly because of various interferences and environmental changes. Current protocols estimate link quality based on the reception of probe packets over a short time period is...

    Provided By University of Virginia

  • White Papers // Mar 2009

    Single-Threaded Mode AVF Prediction During Redundant Execution

    Transient faults can lead to serious errors in execution. Providing protection for the processor core against these faults requires redundant execution, which leads to a performance loss. However, not all bit flips have equal impact on the processor. The Architectural Vulnerability Factor (AVF) quantifies when a soft error is likely...

    Provided By University of Virginia

  • White Papers // Mar 2009

    NBTI-Aware Dynamic Instruction Scheduling

    NBTI is an important emerging silicon reliability problem. In this paper the authors explore a microarchitecture-level approach to mitigate NBTI related failures in the functional units of a superscalar processor.They analyze the impact of dynamic instruction scheduling on NBTI and show that the conventional approach to instruction scheduling can accelerate...

    Provided By University of Virginia

  • White Papers // Apr 2010

    Recovery Boosting: A Technique to Enhance NBTI Recovery in SRAM Arrays

    Negative Bias Temperature Instability (NBTI) is an important lifetime reliability problem in microprocessors. SRAM-based structures within the processor are especially susceptible to NBTI since one of the PMOS devices in the memory cell always has an input of '0'. Previously proposed recovery techniques for SRAM cells aim to balance the...

    Provided By University of Virginia

  • White Papers // Dec 2010

    Modeling and Analyzing NBTI in the Presence of Process Variation

    With continuous scaling of transistors in each technology generation, NBTI and Process Variation (PV) have become very important silicon reliability problems for the microprocessor industry. In this paper, the authors develop an analytical model to capture the impact of NBTI in the presence of PV for use in architecture simulations....

    Provided By University of Virginia

  • White Papers // Jan 2011

    Enviro-Track: Towards an Environmental Computing Paradigm for Distributed Sensor Networks

    Distributed sensor networks are quickly gaining recognition as viable embedded computing platforms. Current techniques for programming sensor networks are cumbersome, inflexible, and low-level. This paper introduces EnviroTrack, an object-based distributed middleware system that raises the level of programming abstraction by providing a convenient and powerful interface to the application developer...

    Provided By University of Virginia

  • White Papers // Feb 2011

    Distributed Uplink Resource Allocation in Cognitive Radio Networks - Part II: Equilibria and Algorithms for Joint Access Point Selection and Power Allocation

    The main objective of this two part paper is to formulate and address the problem of distributed uplink resource allocation in multi-carrier Cognitive Radio Networks (CRN) with multiple Access Points (APs). When the APs operate on non-overlapping spectrum bands, such problem is essentially a joint spectrum decision and spectrum sharing...

    Provided By University of Virginia

  • White Papers // Feb 2011

    Joint Distributed Access Point Selection and Power Allocation in Cognitive Radio Networks

    Spectrum management has been identified as a crucial step towards enabling the technology of the Cognitive Radio Network (CRN). Most of the current works dealing with spectrum management in the CRN focus on a single task of the problem, e.g., spectrum sensing, spectrum decision, spectrum sharing or spectrum mobility. In...

    Provided By University of Virginia

  • White Papers // Aug 2010

    Characterization of User-Perceived Quality of Service (QoS) in Mobile Devices Using Network Pairwise Comparisons

    This paper presents a user-centric and application-specific QoS assessment methodology for cellular communication networks. Specifically, it uses the Analytic Hierarchy Process (AHP) to evaluate QoS as a multi-criteria decision problem that represents how well cellular networks' data services are perceived given particular sets of application classes and relative to other...

    Provided By University of Virginia

  • White Papers // Feb 2011

    Efficient Privacy-Preserving Biometric Identification

    The authors present an efficient matching protocol that can be used in many privacy-preserving biometric identification systems in the semi-honest setting. The most general technical contribution is a new backtracking protocol that uses the byproduct of evaluating a garbled circuit to enable efficient oblivious information retrieval. They also present a...

    Provided By University of Virginia