University of Michigan

Displaying 1-40 of 213 results

  • White Papers // Jan 2015

    Signature-based SER Analysis and Design of Logic Circuits

    In this paper, the authors explore the use of signatures, i.e., partial truth tables generated via bit-parallel functional simulation, during soft error analysis and logic synthesis. They first present a signature based CAD framework that incorporates tools for the logic-level Analysis of Soft Error Rate (AnSER) and for Signature-based Design...

    Provided By University of Michigan

  • White Papers // Jan 2015

    Data Structures and Algorithms for Simplifying Reversible Circuits

    Reversible logic is motivated by low-power design, quantum circuits and nanotechnology. The authors develop a compact representation of small reversible circuits to generate and store optimal circuits for all 40,320 three-input reversible functions and millions of four-input circuits. This allows implementing a function optimally in constant time for use in...

    Provided By University of Michigan

  • White Papers // Jan 2015

    On the Role of Timing Masking in Reliable Logic Circuit Design

    Soft errors, once only of concern in memories, are beginning to affect logic as well. Determining the Soft Error Rate (SER) of a combinational circuit involves three main masking mechanisms: logic, timing and electrical. Most previous papers focus on logic and electrical masking. In this paper, the authors develop static...

    Provided By University of Michigan

  • White Papers // Jan 2015

    Automating Post-Silicon Debugging and Repair

    Modern IC (Integrated Circuit) designs have reached unparalleled levels of complexity, resulting in more and more bugs discovered after design tape-out However, so far only very few EDA tools for post-silicon debugging have been reported in the literature. In this paper, the authors develop a methodology and new algorithms to...

    Provided By University of Michigan

  • White Papers // Jan 2015

    InVerS: An Incremental Verification System with Circuit Similarity Metrics and Error Visualization

    Dramatic increases in design complexity and advances in IC manufacturing technology affect all aspects of circuit performance and functional correctness. As interconnect increasingly dominates delay and power at the latest technology nodes, much effort is invested in physical synthesis optimizations, posing great challenges in validating the correctness of such optimizations....

    Provided By University of Michigan

  • White Papers // Jan 2015

    Automatic Error Diagnosis and Correction for RTL Designs

    Recent improvements in design verification strive to automate the error-detection process and greatly enhance engineers' ability to detect functional errors. However, the process of diagnosing the cause of these errors and fixing them remains difficult and requires significant ad-hoc manual effort. The authors' paper proposes improvements to this aspect of...

    Provided By University of Michigan

  • White Papers // Jan 2015

    Enhancing Design Robustness with Reliability-aware Resynthesis and Logic Simulation

    While circuit density and power efficiency increase with each major advance in IC technology, reliability with respect to soft errors tends to decrease. Current solutions to this problem such as TMR (Triple Modular Redundancy) require high area and power overhead. In this paper, soft-error reliability is improved with minimal area...

    Provided By University of Michigan

  • White Papers // Jan 2015

    On-Chip Test Generation using Linear Subspaces

    A central problem in Built-In Self-Test (BIST) is how to efficiently generate a small set of test vectors that detect all targeted faults. The authors propose a novel solution that uses linear algebraic concepts to partition the vector space of tests into subspaces (clusters). A subspace is defined by a...

    Provided By University of Michigan

  • White Papers // Mar 2014

    Towards a General Method for Building Predictive Models of Learner Success Using Educational Time Series Data

    In this paper, the authors present a pedagogical and instructional-technology general method for building predictive models for education from time series log data. While it is common for models of learner achievement to include cognitive features, they instead are data mining only resource accesses in the learning environment. This has...

    Provided By University of Michigan

  • White Papers // Sep 2013

    Quipu: High-performance Simulation of Quantum Circuits using Stabilizer Frames

    As quantum information processing gains traction, its simulation becomes increasingly significant for engineering purposes - evaluation, testing and optimization - as well as for theoretical research. Generic quantum-circuit simulation appears intractable for conventional computers. However, the researchers identified an important subclass, called stabilizer circuits, which can be simulated efficiently using...

    Provided By University of Michigan

  • White Papers // Mar 2012

    Off-Path TCP Sequence Number Inference Attack How Firewall Middleboxes Reduce Security

    In this paper, the authors report a newly discovered "Off-path TCP sequence number inference" attack enabled by firewall middle-boxes. It allows an off-path (i.e., not man-in-the-middle) attacker to hijack a TCP connection and inject malicious content, effectively granting the attacker write-only permission on the connection. For instance, with the help...

    Provided By University of Michigan

  • White Papers // Jan 2012

    Low Power Interconnects for SIMD Computers

    Driven by continued scaling of Moore's Law, the number of processing elements on a die is increasing dramatically. Recently there has been a surge of wide single instruction multiple data architectures designed to handle computationally intensive applications like 3D graphics, high definition video, image processing, and wireless communication. A limit...

    Provided By University of Michigan

  • White Papers // Jan 2012

    Trusted Collaborative Spectrum Sensing for Mobile Cognitive Radio Networks

    Collaborative spectrum sensing is a key technology in Cognitive Radio Networks (CRNs). It is inaccurate if spectrum sensing nodes are malicious. Although mobility is an inherent property of wireless networks, there has been no prior work studying the detection of malicious users for collaborative spectrum sensing in mobile CRNs. Existing...

    Provided By University of Michigan

  • White Papers // Jan 2012

    System-Level Implications of Disaggregated Memory

    Recent research on memory disaggregation introduces a new architectural building block - the memory blade - as a cost-effective approach for memory capacity expansion and sharing for an ensemble of blade servers. Memory blades augment blade servers' local memory capacity with a second-level (remote) memory that can be dynamically apportioned...

    Provided By University of Michigan

  • White Papers // Jan 2012

    Is Diversity Gain Worth the Pain: Performance Comparison Between Opportunistic Multi-Channel MAC and Single-Channel MAC

    In this paper, the authors analyze the delay performance of an opportunistic multi-channel medium access control scheme and compare it to that of the corresponding single channel MAC scheme. In the opportunistic multi-channel MAC scheme, they assume that the pair of sender/receiver is able to evaluate the channel quality after...

    Provided By University of Michigan

  • White Papers // Jan 2012

    Approximately Optimal Adaptive Learning in Opportunistic Spectrum Access

    In this paper, the authors develop an adaptive learning algorithm which is approximately optimal for an Opportunistic Spectrum Access (OSA) problem with polynomial complexity. In this OSA problem each channel is modeled as a two state discrete time Markov chain with a bad state which yields no reward and a...

    Provided By University of Michigan

  • White Papers // Jan 2012

    BulletProof: A Defect?Tolerant CMP Switch Architecture

    As silicon technologies move into the nanometer regime, transistor reliability is expected to wane as devices become subject to extreme process variation, particle-induced transient errors, and transistor wear-out. Unless these challenges are addressed, computer vendors can expect low yields and short mean-times-to-failure. In this paper, the authors examine the challenges...

    Provided By University of Michigan

  • White Papers // Jan 2012

    SODA: A Lowpower Architecture for Software Radio

    The physical layer of most wireless protocols is traditionally implemented in custom hardware to satisfy the heavy computational requirements while keeping power consumption to a minimum. These implementations are time consuming to design and difficult to verify. A programmable hardware platform capable of supporting software implementations of the physical layer,...

    Provided By University of Michigan

  • White Papers // Jan 2012

    SPEX: A Programming Language for Software Defined Radio

    High-throughput, low-power Software Defined Radio(SDR) solutions require multi-core SIMD DSP processors to meet real-time performance requirements. Given the difficulty in programming traditional DSPs, these new multi-core signal processors provide even greater challenges for programmers and compilers. In this paper, the authors describe SPEX, a programming language which is aimed at...

    Provided By University of Michigan

  • White Papers // Jan 2012

    Data Access Partitioning for Fine-Grain Parallelism on Multicore Architectures

    The recent design shift towards multicore processors has spawned a significant amount of research in the area of program parallelization. The future abundance of cores on a single chip requires programmer and compiler intervention to increase the amount of parallel work possible. Much of the recent work has fallen into...

    Provided By University of Michigan

  • White Papers // Jan 2012

    Extending Multicore Architectures to Exploit Hybrid Parallelism in Single-Thread Applications

    Chip multiprocessors with multiple simpler cores are gaining popularity because they have the potential to drive future performance gains without exacerbating the problems of power dissipation and complexity. Current chip multiprocessors increase throughput by utilizing multiple cores to perform computation in parallel. These designs provide real benefits for server-class applications...

    Provided By University of Michigan

  • White Papers // Jan 2012

    Transform Coding of Densely Sampled Gaussian Data

    With mean-squared error D as a goal, it is well known that one may approach the Rate-Distortion function R(D) of a non-bandlimited, continuous-time Gaussian source by sampling at a sufficiently high rate, applying the Karhunen-Loeve transform to sufficiently long blocks, and then independently coding the transform coefficients of each type....

    Provided By University of Michigan

  • White Papers // Jan 2012

    Representation of Correlated Sources Into Graphs for Transmission Over Broadcast Channels

    In this paper, the authors consider the communication problem that involves transmission of correlated sources over broadcast channels. They consider a graph-based framework for this information transmission problem. The system involves a source coding module and a channel coding module. In the source coding module, the sources are efficiently represented...

    Provided By University of Michigan

  • White Papers // Jan 2012

    The Effect of Node Density and Propagation Model on Throughput Scaling of Wireless Networks

    The paper has led to many studies of scaling laws for the asymptotically achievable throughput in wireless networks under a variety of network models and assumptions. Such scaling laws help one understand the fundamental performance limits of these networks and how efficiency changes as network conditions change. Some examples include...

    Provided By University of Michigan

  • White Papers // Dec 2011

    Atomic Congestion Games on Graphs and Its Applications in Networking

    In this paper, the authors introduce and analyze the properties of a class of game, the Atomic Congestion Game on Graphs (ACGG), which is a generalization of the classical congestion game. In particular, the ACGG captures the spatial information which is often ignored in the classical congestion game. This is...

    Provided By University of Michigan

  • White Papers // Dec 2011

    Securely Sealing Multi-FPGA Systems

    The importance of hardware security of electronic systems is rapidly increasing due to the increasing reliance of mass-produced and mission-critical systems on embedded electronics and the ever-growing supply chains that disentangle chip designers and manufacturers from OEMs. The authors work shows how to dramatically reduce vulnerability to Trojan-horse injection and...

    Provided By University of Michigan

  • White Papers // Dec 2011

    Full-System Analysis and Characterization of Interactive Smartphone Applications

    Smartphones have recently overtaken PCs as the primary consumer computing device in terms of annual unit shipments. Given this rapid market growth, it is important that mobile system designers and computer architects analyze the characteristics of the interactive applications users have come to expect on these platforms. With the introduction...

    Provided By University of Michigan

  • White Papers // Dec 2011

    Information Rates of Densely Sampled Gaussian Data: Distributed Vector Quantization and Scalar Quantization With Transforms

    Motivated by the question of the efficiency of dense sensor networks for sampling and encoding spatial random fields, this paper investigates the rates attainable by several lossy schemes for coding a Gaussian random field to a specified mean-squared error distortion based on sampling at asymptotically large rates. In the first,...

    Provided By University of Michigan

  • White Papers // Dec 2011

    Scalability and Efficiency of Push-Driven P2PTV Systems

    TeleVision transmitted over IP (IPTV) presents numerous opportunities for users as well as service providers, and has attracted significant interest from industry as well as research communities in recent years. Among the emerging IPTV delivery architectures, the peer-to-peer based delivery mechanism is considered attractive due to the relative ease of...

    Provided By University of Michigan

  • White Papers // Nov 2011

    You Can Run, But You Can't Hide: Exposing Network Location for Targeted DoS Attacks in Cellular Networks

    An important class of attacks against cellular network infrastructures, i.e., signaling DoS attack, paging channel overload, and channel exhaustion attack, operates by sending low rate data traffic to a large number of mobile devices at a particular location to exhaust bottleneck resources such as radio resource and radio resource controller....

    Provided By University of Michigan

  • White Papers // Nov 2011

    Error Exponent for Multiple-Access Channels: Upper Bounds

    The problem of bounding the reliability function of a Multiple-Access Channel (MAC) is studied. Two new upper bounds on the error exponent of a two-user Discrete Memoryless (DM) Multiple-Access Channel (MAC) are derived. The first bound (sphere packing) is an upper bound on the average error exponent and is the...

    Provided By University of Michigan

  • White Papers // Oct 2011

    PEPSC: A Power-Efficient Processor for Scientific Computing

    The rapid advancements in the computational capabilities of the Graphics Processing Unit (GPU) as well as the deployment of general programming models for these devices have made the vision of a desktop supercomputer a reality. It is now possible to assemble a system that provides several TFLOPs of performance on...

    Provided By University of Michigan

  • White Papers // Oct 2011

    Automatic Root-Cause Diagnosis of Performance Anomalies in Production Software

    Troubleshooting the performance of complex production software is challenging. Most existing tools, such as profiling, tracing, and logging systems, reveal what events occurred during performance anomalies. However, the users of such tools must then infer why these events occurred during a particular execution; e.g., that their execution was due to...

    Provided By University of Michigan

  • White Papers // Sep 2011

    Low Overhead Control Channels in Wireless Networks

    Low-latency, low-overhead and reliable control channels are essential to the efficient operation of wireless networks. However, control channels that utilize current in-band and out-of-band designs do not fully meet this requirement. In this paper, the authors design and implement Aileron, a novel control channel based on automatic modulation recognition that...

    Provided By University of Michigan

  • White Papers // Sep 2011

    Algorithmic Tuning of Clock Trees and Derived Non-Tree Structures

    Clock-network synthesis significantly impacts the performance, area and power dissipation of an integrated circuit and this impact is aggravated when architectural-level pipelining increases the number of clocked elements. This mini-tutorial covers recent research on clock network tuning. It starts with SPICE-accurate optimizations used in winning entries at the ISPD 2009...

    Provided By University of Michigan

  • White Papers // Sep 2011

    Detecting and Surviving Data Races Using Complementary Schedules

    Data races are a common source of errors in multithreaded programs. In this paper, the authors show how to protect a program from data race errors at runtime by executing multiple replicas of the program with complementary thread schedules. Complementary schedules are a set of replica thread schedules crafted to...

    Provided By University of Michigan

  • White Papers // Aug 2011

    Network Coding Aware Dynamic Subcarrier Assignment in OFDMA Based Wireless Networks

    Orthogonal Frequency Division Multiple Access (OFDMA) has been integrated into emerging broadband wireless systems such as the 802.16 wirelessMAN. A critical problem in OFDMA is to assign multiple frequency bands (called subcarriers) to different users. Taking advantage of the frequency diversity and multiuser diversity in OFDMA systems, dynamic subcarrier assignment...

    Provided By University of Michigan

  • White Papers // Aug 2011

    Towards Name-Based Trust and Security for Content-Centric Network

    Trust and security have been considered as built-in properties for future Internet architecture. Leveraging the concept of named content in recently proposed information centric network, the authors propose a name-based trust and security protection mechanism. Their scheme is built with Identity-Based Cryptography (IBC), where the identity of a user or...

    Provided By University of Michigan

  • White Papers // Aug 2011

    Functional Correctness for CMP Interconnects

    As transistor counts continue to scale, modern designs are transitioning towards large Chip Multi-Processors (CMPs). In order to match the advancing performance of CMPs, on-chip interconnects are becoming increasingly complex, commonly deploying advanced Network-on-Chip (NoC) structures. Ensuring the correct operation of these system-level infrastructures has become increasingly problematic and, in...

    Provided By University of Michigan

  • White Papers // Aug 2011

    Post-Silicon Bug Diagnosis With Inconsistent Executions

    The complexity of modern chips intensifies verification challenges, and an increasing share of this verification effort is shouldered by post-silicon validation. Focusing on the first silicon prototypes, post-silicon validation poses critical new challenges such as intermittent failures, where multiple executions of a same test do not yield a consistent outcome....

    Provided By University of Michigan

  • White Papers // May 2010

    Security and Privacy in Emerging Wireless Networks

    Wireless communication continues to make in-roads into many facets of the society and gradually becomes more and more ubiquitous. While, in the past, wireless communication (as well as mobility) was largely limited to first and last transmission hops, today's wireless networks are starting to offer purely wireless, often mobile, and...

    Provided By University of Michigan

  • White Papers // Apr 2011

    Recognizing Human Actions by Attributes

    In this paper, the authors explore the idea of using high-level se-mantic concepts, also called attributes, to represent human actions from videos and argue that attributes enable the construction of more descriptive models for human action recognition. They propose a unified framework wherein manually specified attributes are: selected in a...

    Provided By University of Michigan

  • White Papers // Sep 2009

    Application-Layer Intrusion Detection in MANETs

    Security has become important to Mobile Ad hoc NETworks (MANETs) due mainly to their use for many mission- and life-critical applications. However, the broadcast nature of inter-node communications and node mobility in MANETs make it very challenging to secure MANETs. Moreover, their constantly-changing topology causes network node density and neighbor...

    Provided By University of Michigan

  • White Papers // Sep 2010

    The Effects Of The Financial Crisis On The Well?]Being Of Older Americans: Evidence From The Cognitive Economics Study

    This paper uses the Cognitive Economics Study (CogEcon) to assess the effect of the financial crisis on the well-being of older Americans. Financial wealth fell by about 15 percent for the median household. These financial losses were concentrated among households with high levels of wealth and high cognitive capacities, which...

    Provided By University of Michigan

  • White Papers // Feb 2011

    Automated Construction of Fast and Accurate System-Level Models for Wireless Sensor Networks

    Rapidly and accurately estimating the impact of design decisions on performance metrics is critical to both the manual and automated design of wireless sensor networks. Estimating system-level performance metrics such as lifetime, data loss rate, and network connectivity is particularly challenging because they depend on many factors, including network design...

    Provided By University of Michigan

  • White Papers // Sep 2009

    Defeating Vanish With Low-Cost Sybil Attacks Against Large DHTs

    Researchers at the University of Washington recently proposed Vanish, a system for creating messages that automatically "Self-destruct" after a period of time. Vanish works by encrypting each message with a random key and storing shares of the key in a large, public Distributed Hash Table (DHT). Normally, DHTs expunge data...

    Provided By University of Michigan

  • White Papers // Sep 2010

    Mortgage Contract Decisions And Mortgage Distress: Family And Financial Life-cycle Factors

    The U.S. economy experienced a dramatic rise in the price of owner occupied housing during 1999-2007, and then a precipitous decline from 2007 through 2009. In this paper, the authors utilize data from the Panel Study of Income Dynamics (PSID) during 1999-2009 to study first the factors and borrowing decisions...

    Provided By University of Michigan

  • White Papers // Jan 2011

    Supporting Africa's Post-Crisis Growth: The Role Of Macroeconomic Policies

    The objective of this paper is to discuss macroeconomic policies that would help African countries, especially the low income countries, reach strong, sustained and shared growth in the post-crisis world. The paper first reviews, with a special focus on LICs, macroeconomic policies in Africa prior to the crisis. It then...

    Provided By University of Michigan

  • White Papers // Sep 2009

    Attack-Tolerant Distributed Sensing for Dynamic Spectrum Access Networks

    Accurate sensing of the spectrum condition is of crucial importance to the mitigation of the spectrum scarcity problem in Dynamic Spectrum Access (DSA) networks. Specifically, distributed sensing has been recognized as a viable means to enhance the incumbent signal detection by exploiting the diversity of sensors. However, it is challenging...

    Provided By University of Michigan

  • White Papers // Sep 2010

    Automating Configuration Troubleshooting With Dynamic Information Flow Analysis

    Software misconfigurations are time-consuming and enormously frustrating to troubleshoot. In this paper, the authors show that dynamic information flow analysis helps solve these problems by pinpointing the root cause of configuration errors. They have built a tool called ConfAid that instruments application binaries to monitor the causal dependencies introduced through...

    Provided By University of Michigan

  • White Papers // Mar 2011

    Is Economic Growth Associated With Reduction In Child Undernutrition In India?

    Economic growth is widely perceived as a major policy instrument in reducing childhood undernutrition in India. The authors assessed the association between changes in state per capita income and the risk of undernutrition among children in India. Data for this analysis came from three cross-sectional waves of the National Family...

    Provided By University of Michigan

  • White Papers // Jan 2011

    How Prior Military Experience Influences The Future Militarized Behavior Of Leaders

    This paper joins a growing number of studies that are moving beyond the question of simply whether leaders matter for international politics to examine the scope conditions under which leaders matter. This is not to say that structural and unit-level variables do not matter. The people should, however, take full...

    Provided By University of Michigan

  • White Papers // Jan 2010

    On Sensing - Access Tradeoff in Cognitive Radio Networks

    In Cognitive Radio Networks (CRNs), the design of an optimal spectrum sensing scheme is an important problem that has recently been drawing consideration attention. Various sensing-related performance tradeoffs have been studied as an efficient means to maximize the secondary network performance. Despite its importance, however, the sensing - access tradeoff...

    Provided By University of Michigan

  • White Papers // Dec 2010

    Cognitive Radios for Dynamic Spectrum Access: From Concept to Reality

    This paper provides a comprehensive survey of cognitive radio technology, focusing on its application to dynamic spectrum access, especially from the perspective of realizing consumer-oriented CR networks. They first overview the state of the art in CR technology and identify its key functions across the protocol stack, such as spectrum...

    Provided By University of Michigan

  • White Papers // Jan 2011

    Opportunistic Spectrum Access for Mobile Cognitive Radios

    Abstract - Cognitive Radios (CRs) can mitigate the impending spectrum scarcity problem by utilizing their capability of accessing licensed spectrum bands opportunistically. While most existing work focuses on enabling such opportunistic spectrum access for stationary CRs, mobility is an important concern to Secondary Users (SUs) because future mobile devices are...

    Provided By University of Michigan

  • White Papers // Feb 2011

    Wi-Fi 2.0: Price and Quality Competitions of Duopoly Cognitive Radio Wireless Service Providers With Time-Varying Spectrum Availability

    The WhiteSpaces (WS) in the legacy spectrum provide new opportunities for the future Wi-Fi-like Internet access, often called Wi-Fi 2.0, since service quality can be greatly enhanced thanks to the better propagation characteristics of the WS than the ISM bands. In the Wi-Fi 2.0 networks, each Wireless Service Provider (WSP)...

    Provided By University of Michigan

  • White Papers // Jun 2011

    Access Point Selection Under Emerging Wireless Technologies

    Users of wireless networks increasingly face a choice among multiple available access points. Clients generally make this decision with limited information about the access points or traffic trends in the system. The authors examine the strategic implications of an emerging wireless technology: utilizing multiple Access Points (APs) simultaneously. Clients using...

    Provided By University of Michigan

  • White Papers // Feb 2011

    Robust Cooperative Sensing Via State Estimation in Cognitive Radio Networks

    Cooperative sensing, a key enabling technology for dynamic spectrum access, is vulnerable to various sensing targeted attacks, such as the primary user emulation or spectrum sensing data falsification. These attacks can easily disrupt the primary signal detection process, thus crippling the operation of dynamic spectrum access. While such sensing-targeted attacks...

    Provided By University of Michigan

  • White Papers // Dec 2009

    Chorus: Collision Resolution for Efficient Wireless Broadcast

    Traditional wireless broadcast protocols rely heavily on the 802.11-based CSMA/CA model, which avoids interference and collision by conservatively scheduling transmissions. While CSMA/CA is amenable to multiple concurrent unicasts, it tends to degrade broadcast performance, especially when there are a large number of nodes and links are lossy. In this paper,...

    Provided By University of Michigan

  • White Papers // Dec 2009

    Spatio-Temporal Fusion for Small-Scale Primary Detection in Cognitive Radio Networks

    In Cognitive Radio Networks (CRNs), detecting small-scale primary devices - such as Wireless Microphones (WMs) - is a challenging, but very important, problem that has not yet been addressed well. The authors identify the data-fusion range as a key factor that enables effective cooperative sensing for detection of small-scale primary...

    Provided By University of Michigan

  • White Papers // May 2011

    Does Low-Power Design Imply Energy Efficiency for Data Centers?

    Data center efficiency has quickly become a first-class design goal. In response, many studies have emerged from the academic community and industry using low-power design to help improve the energy efficiency of server hardware. Generally, these proposals hold the assumption that low-power design is inherently better for energy efficiency; this...

    Provided By University of Michigan

  • White Papers // Feb 2011

    Towards a Scalable Data Center-Level Evaluation Methodology

    As the popularity of Internet services continues to rise, the need to understand the design of the data center systems hosting these workloads becomes increasingly important. Unfortunately, research in this area has been stifled, primarily due to a lack of tools, workloads, and rigorous evaluation methodology. Traditional tools, such as...

    Provided By University of Michigan

  • White Papers // Oct 2009

    Multi-Channel Opportunistic Access: A Case of Restless Bandits With Multiple Plays

    This paper considers the following stochastic control problem that arises in opportunistic spectrum access: a system consists of n channels where the state ("Good" or "Bad") of each channel evolves as independent and identically distributed Markov processes. A user can select exactly k channels to sense and access (based on...

    Provided By University of Michigan

  • White Papers // Jan 2011

    Minimizing Power Consumption in Sensor Networks With Quality of Service Requirement

    Minimizing energy and power consumption in wireless sensor networks is critical in extending the lifetime of the network. In this paper the authors consider efficient power/rate allocation strategies with certain quality of service constraints. The transmission rate achieved and the power used are related by a power-rate function for a...

    Provided By University of Michigan

  • White Papers // Jul 2009

    Do You Know Where Your Data's Been? - Tamper-Evident Database Provenance

    Database provenance chronicles the history of updates and modifications to data, and has received much attention due to its central role in scientific data management. However, the use of provenance information still requires a leap of faith. Without additional protections, provenance records are vulnerable to accidental corruption, and even malicious...

    Provided By University of Michigan

  • White Papers // Jul 2009

    SPAN: A Unified Framework and Toolkit for Querying Heterogeneous Access Policies

    Incorrect policy configurations are a major cause of security failures in large-scale systems. Policy analyzers and testing tools can help with this, but often the tools are specific to one type of policy (e.g., firewalls). In contrast, the most insidious security problems often require understanding the interactions of policies across...

    Provided By University of Michigan

  • White Papers // Mar 2010

    Sensor Scheduling for Multi-Parameter Estimation Under an Energy Constraint

    The authors consider a sensor scheduling problem for estimating multiple independent Gaussian random variables under an energy constraint. The sensor measurements are described by a linear observation model; the observation noise is assumed to be Gaussian. They formulate this problem as a stochastic sequential allocation problem. Due to the Gaussian...

    Provided By University of Michigan

  • White Papers // Feb 2011

    Power Allocation and Spectrum Sharing in Multi-User, Multi-Channel Systems With Strategic Users

    The authors consider the decentralized power allocation and spectrum sharing problem in multi-user, multichannel systems with strategic users. They resent a mechanism/game form that has the following desirable features. It is individually rational. It is budget balanced at every Nash equilibrium of the game induced by the game form as...

    Provided By University of Michigan

  • White Papers // Feb 2010

    Channel Estimation for Opportunistic Spectrum Sensing: Uniform and Random Sensing

    The knowledge of channel statistics, as a result of random fading, interference, and primary user activities, can be very helpful for a secondary user in making sound opportunistic spectrum access decisions in a cognitive radio network. It is therefore desirable to be able to efficiently and accurately estimate channel statistics,...

    Provided By University of Michigan

  • White Papers // Jan 2011

    Asymptotic Connectivity of Low Duty-Cycled Wireless Sensor Networks

    In this paper the authors study the asymptotic connectivity of a low duty-cycled wireless sensor network, where all sensors are randomly duty-cycled such that they are on/active at any time with a fixed probability. A wireless network is often said to be asymptotically connected if there exists a path from...

    Provided By University of Michigan

  • White Papers // Jan 2011

    Counting Twig Matches in a Tree

    The authors describe efficient algorithms for accurately estimating the number of matches of a small node-labeled tree, i.e., a twig, in a large node-labeled tree, using a summary data structure. This problem is of interest for queries on XML and other hierarchical data, to provide query feedback and for cost-based...

    Provided By University of Michigan

  • White Papers // Jul 2008

    Do Choice & Speed Of Reforms Matter For Human Rights During Transition?

    Conventional wisdom posits absence of systematic relationship between economic reforms and human rights. Taking the case of transition economies, Vadlamannati & Soysa (2008) shows significant positive relationship between economic reforms and various forms of human rights. This brings us to the next question on the impact of choice and speed...

    Provided By University of Michigan

  • White Papers // Aug 2010

    The Role Of Financial Factors In The Trade Collapse: A Skeptics View

    This paper explores the role of financial factors in the 2008-9 collapse of U.S. imports and exports. Using highly disaggregated international trade data, the authors examine whether the cross-sectoral variation in how much imports or exports fell during this episode can be explained by financial variables. To do this, they...

    Provided By University of Michigan

  • White Papers // Aug 2009

    Extending Likages Between Organizational Analysis And Social Structure: A Case Study Of The Celebrity-construction Of A Chinese Marketplace

    This paper examines the emergence of firm-celebrity, both an intangible-asset, and a facilitator of competitive advantage. Institutional approaches have asserted that organizations from the same organizational field and characterized by comparable structural positions face similar structural forces. These result in isomorphic tendencies, and similarities among firms. But, in any organizational...

    Provided By University of Michigan

  • White Papers // Aug 2009

    Chinese State?s Economic Cooperation Related Investment: An Investigation Of Its Direction And Some Implications For Outward Investment

    The Chinese state undertakes large scale investments in a number of countries under the auspices of Economic Cooperation related Investment (ECI). While there are suggestions that it is an extension of China's soft power aimed at facilitating Chinese FDI in those countries, often for access to natural resources, there is...

    Provided By University of Michigan

  • White Papers // Sep 2010

    Price Convergence And Market Integration In Russia

    After a period of growing disconnectedness of regional markets following the 1992 price liberalization in Russia, a process of improvement in market integration started since about 1994. This paper analyzes the spatial pattern of goods market integration in the country in 1994-2000, characterizing Russian regions into three states: integrated with...

    Provided By University of Michigan

  • White Papers // Sep 2010

    Bank Efficiency In Transitional Countries: Sensitivity To Stochastic Frontier Design

    This paper provides an empirical insight on the heterogeneity in the estimates of banking efficiency produced by the stochastic frontier approach. Using data from five countries of Central and Eastern Europe, the authors study the sensitivity of the efficiency score and the efficiency ranking to a change in the design...

    Provided By University of Michigan

  • White Papers // Jun 2010

    EU Enlargement And Monetary Regimes From The Insurance Model Perspectives

    Some ten years ago, Michael Dooley (Dooley, 1997; Dooley, 2000) put forward an insurance model of currency crises, which after some modifications gives a good theoretical basis for explanation of the overall dynamics of the post communist transformation and diversity across countries and periods. The paper analyses, within the framework...

    Provided By University of Michigan

  • White Papers // Jun 2010

    Which Foreigners Are Worth Wooing? A Meta-analysis Of Vertical Spillovers From FDI

    The principal argument for subsidizing foreign investment, especially in developing and transition economies, is the assumed spillover of technology to local firms. Yet researchers report mixed results on spillovers. To examine the phenomenon in a systematic way, the authors collected 3,626 estimates from 57 empirical studies on between-sector spillovers and...

    Provided By University of Michigan

  • White Papers // Jun 2010

    Environmental Regulation And Competitiveness: Evidence From Romania

    According to the pollution haven hypotheses differences in environmental regulation affect trade flows and plant location. Specifically, environmental stringency should decrease exports and increase imports of "Dirty" goods. This paper estimates a gravity model to establish whether the implementation of more stringent regulations in Romania has indeed affected its competitiveness...

    Provided By University of Michigan