University of Tennessee

Displaying 1-40 of 52 results

  • White Papers // Jul 2014

    Multi-Elimination ILU Preconditioners on GPUs

    Iterative solvers for sparse linear systems often benefit from using preconditioners. While there are implementations for many iterative methods that leverage the computing power of accelerators, porting the latest developments in preconditioners to accelerators has been challenging. In this paper, the authors develop a self-adaptive multi-elimination preconditioner for Graphics Processing...

    Provided By University of Tennessee

  • White Papers // Jul 2014

    Optimizing Krylov Subspace Solvers on Graphics Processing Units

    Krylov subspace solvers are often the method of choice when solving sparse linear systems iteratively. At the same time, hardware accelerators such as Graphics Processing Units (GPUs) continue to offer significant floating point performance gains for matrix and vector computations through easy-to-use libraries of computational kernels. However, as these libraries...

    Provided By University of Tennessee

  • White Papers // Aug 2012

    Joint Congestion Control and Routing Subject to Dynamic Interruptions in Cognitive Radio Networks

    Cognitive radio networks suffer from dynamic interruptions from primary users. The joint congestion control and routing are tackled using stochastic control techniques. Centralized dynamic programming is applied for the primal optimization, which provides a performance upper bound. Q-learning is applied when the primary user knowledge is unknown. Dual optimization based...

    Provided By University of Tennessee

  • White Papers // Apr 2012

    Efficient and Secure Wireless Communications for Advanced Metering Infrastructure in Smart Grids

    An experiment is carried out to measure the power consumption of households. The analysis on the real measurement data shows that the significant change of power consumption arrives in a Poisson manner. Based on this experiment, a novel wireless communication scheme is proposed for the Advanced Metering Infrastructure (AMI) in...

    Provided By University of Tennessee

  • White Papers // Jan 2012

    Fine-Grained Private Matching for Proximity-Based Mobile Social Networking

    Proximity-based Mobile Social Networking (PMSN) refers to the social interaction among physically proximate mobile users directly through the Bluetooth/WiFi interfaces on their smartphones or other mobile devices. It becomes increasingly popular due to the recently explosive growth of smartphone users. Profile matching means two users comparing their personal profiles and...

    Provided By University of Tennessee

  • White Papers // Oct 2011

    Collaborative Scheduling in Highly Dynamic Environments Using Error Inference

    Energy constraint is a critical hurdle hindering the practical deployment of long-term wireless sensor network applications. Turning off (i.e., duty cycling) sensors could reduce energy consumption, however at the cost of low sensing fidelity due to sensing gaps introduced. Existing techniques have studied how to collaboratively reduce the sensing gap...

    Provided By University of Tennessee

  • White Papers // Jun 2011

    Evaluation of the HPC Challenge Benchmarks in Virtualized Environments

    This paper evaluates the performance of the HPC Challenge benchmarks in several virtual environments, including VMware, KVM and VirtualBox. The HPC Challenge benchmarks consist of a suite of tests that examine the performance of HPC architectures using kernels with memory access patterns more challenging than those of the High Performance...

    Provided By University of Tennessee

  • White Papers // Apr 2011

    Cross-Network Spectrum Sensing for Mission-Critical Cognitive Radio Networks: Collaboration Through Gateways

    In this paper, the cross-network spectrum sensing is considered for future mission-critical wireless networks employing cognitive radio technology. In military operations and disaster relief efforts, multiple cognitive radio networks may be deployed in the same geographical area for different organizations to access the spectrum collaboratively and provide much needed interoperability...

    Provided By University of Tennessee

  • White Papers // Apr 2011

    Cache-Aware Utilization Control for Energy Efficiency in Multi-Core Real-Time Systems

    Multi-core processors are anticipated to become a major development platform for real-time systems. However, existing power management algorithms are not designed to sufficiently utilize the features available in many multi-core processors, such as shared L2 caches and per-core DVFS, to effectively minimize processor energy consumption while providing real-time guarantees. In...

    Provided By University of Tennessee

  • White Papers // Apr 2011

    Identity-Based Cryptography for Cloud Security

    Cloud computing is a style of computing in which dynamically scalable and commonly virtualized resources are provided as a service over the Internet. This paper, first presents a novel Hierarchical Architecture for Cloud Computing (HACC). Then, Identity-Based Encryption (IBE) and Identity-Based Signature (IBS) for HACC are proposed. Finally, an Authentication...

    Provided By University of Tennessee

  • White Papers // Mar 2011

    Towards Optimal Sensor Placement for Hot Server Detection in Data Centers

    Recent studies have shown that a significant portion of the total energy consumption of many data centers is caused by the inefficient operation of their cooling systems. Without effective thermal monitoring with accurate location information, the cooling systems often use unnecessarily low temperature set points to overcool the entire room,...

    Provided By University of Tennessee

  • White Papers // Feb 2011

    AONT-RS: Blending Security and Performance in Dispersed Storage Systems

    Dispersing files across multiple sites yields a variety of obvious benefits, such as availability, proximity and reliability. Less obviously, it enables security to be achieved without relying on encryption keys. Standard approaches to dispersal either achieve very high security with correspondingly high computational and storage costs, or low security with...

    Provided By University of Tennessee

  • White Papers // Jan 2011

    Color in influence on Accuracy of 3D Scanners Based on Structured Light

    The characterization of commercial 3D scanners allows acquiring precise and useful data. The accuracy of range and, more recently, color for 3D scanners is usually studied separately, but when the 3D scanner is based on structured light with a color coding pattern, color influence on range accuracy should be investigated....

    Provided By University of Tennessee

  • White Papers // Jan 2011

    A Progressive Approach to Distributed Multiple Target Detection in Sensor Networks

    In this paper, the authors study the multiple target detection problem in sensor networks. Due to the resource limitations of sensor networks, the multiple target detection approach has to be energy-efficient and bandwidth-efficient. The existing centralized solutions cannot satisfy these requirements. They present a progressive detection approach based on the...

    Provided By University of Tennessee

  • White Papers // Jan 2011

    Effective VM Sizing in Virtualized Data Centers

    In this paper, the authors undertake the problem of server consolidation in virtualized data centers from the perspective of approximation algorithms. They formulate server consolidation as a stochastic bin packing problem, where the server capacity and an allowed server overflow probability p are given, and the objective is to assign...

    Provided By University of Tennessee

  • White Papers // Dec 2010

    R-Kernel: An Operating System Foundation for Highly Reliable Networked Embedded Systems

    In this paper, the authors present r-kernel, an operating system kernel enhancement specifically designed to improve software reliability in networked embedded systems. The key novelty of r-kernel lies in that it exploits the time dimension of software execution to improve robustness. Specifically, r-kernel keeps track of the execution of applications...

    Provided By University of Tennessee

  • White Papers // Dec 2010

    Learning Restricted Bayesian Network Structures

    Bayesian networks are basic graphical models, used widely both in statistics and artificial intelligence. These statistical models of conditional independence structure are described by acyclic directed graphs whose nodes correspond to (random) variables in consideration. A quite important topic is the learning of Bayesian network structures, which is determining the...

    Provided By University of Tennessee

  • White Papers // Oct 2010

    Adaptive Power Control With Online Model Estimation for Chip Multiprocessors

    As Chip Multiprocessors (CMPs) become the main trend in processor development, various power and thermal management strategies have recently been proposed to optimize system performance while controlling the power or temperature of a CMP chip to stay below a constraint. The availability of per-core DVFS (Dynamic Voltage and Frequency Scaling)...

    Provided By University of Tennessee

  • White Papers // Oct 2010

    Combating False Reports for Secure Networked Control in Smart Grid Via Trustiness Evaluation

    Smart grid, equipped with modern communication infrastructures, is subject to possible cyber attacks. Particularly, false report attacks which replace the sensor reports with fraud ones may cause the instability of the whole power grid or even result in a large area blackout. In this paper, a trustiness system is introduced...

    Provided By University of Tennessee

  • White Papers // Oct 2010

    Decoding the 'Nature Encoded' Messages for Distributed Energy Generation Control in Microgrid

    The communication for the control of Distributed Energy Generation (DEG) in microgrid is discussed. Due to the requirement of real-time transmission, weak or no explicit channel coding is used for the message of system state. To protect the reliability of the uncoded or weakly encoded messages, the system dynamics are...

    Provided By University of Tennessee

  • White Papers // Oct 2010

    Integrating Utilization Control With Task Consolidation for Power Optimization in Multi-Core Real-Time Systems

    Since multi-core processors have become a primary trend in processor development, new scheduling algorithms are needed to minimize power consumption while achieving the desired timeliness guarantees for multi-core (and many-core) real-time embedded systems. Although various power/energy efficient scheduling algorithms have recently been proposed, existing studies may have degraded runtime performance...

    Provided By University of Tennessee

  • White Papers // Oct 2010

    Cache-Aware Utilization Control for Energy-Efficient Multi-Core Real-Time Systems

    Multi-core processors are anticipated to become a major development platform for real-time systems. However, existing power management algorithms are not designed to sufficiently utilize the features available in many multi-core processors, such as shared L2 caches and per-core DVFS, to effectively minimize processor energy consumption while providing real-time guarantees. In...

    Provided By University of Tennessee

  • White Papers // Oct 2010

    Dynamic Multi-Layer Signature Based Intrusion Detection System Using Mobile Agents

    Intrusion detection systems have become a key component in ensuring the safety of systems and networks. As networks grow in size and speed continues to increase, it is crucial that efficient scalable techniques should be developed for IDS systems. Signature based detection is the most extensively used threat detection technique...

    Provided By University of Tennessee

  • White Papers // Sep 2010

    Power Optimization With Performance Assurance for Multi-Tier Applications in Virtualized Data Centers

    Modern data centers must provide performance assurance for complex system software such as multi-tier web applications. In addition, the power consumption of data centers needs to be minimized to reduce operating costs and avoid system overheating. Various power-efficient performance management strategies have been proposed based on Dynamic Voltage and Frequency...

    Provided By University of Tennessee

  • White Papers // Sep 2010

    Deep Spatiotemporal Feature Learning With Application to Image Classification

    Deep machine learning is an emerging framework for dealing with complex high-dimensionality data in a hierarchical fashion which draws some inspiration from biological sources. Despite the notable progress made in the field, there remains a need for an architecture that can represent temporal information with the same ease that spatial...

    Provided By University of Tennessee

  • White Papers // Aug 2010

    Application Feedback in Guiding a Deep-Layered Perception Model

    Deep-layer machine learning architectures continue to emerge as a promising biologically-inspired framework for achieving scalable perception in artificial agents. State inference is a consequence of robust perception, allowing the agent to interpret the environment with which it interacts and map such interpretation to desirable actions. However, in existing deep learning...

    Provided By University of Tennessee

  • White Papers // Jun 2010

    Resource Allocation With EGOS Constraint in Multicell OFDMA Communication Systems: Combating Intercell Interference

    Resource (power and bandwidth) allocation is an important issue in Orthogonal Frequency Division Multiple Access (OFDMA) systems. For multicell systems, the interference across different cells makes the optimization of resource allocation difficult. For finite systems, a constraint on the Rise Over Thermal (ROT) is placed to alleviate the intercell interference....

    Provided By University of Tennessee

  • White Papers // Jun 2010

    Dynamic Thermal and Timeliness Guarantees for Distributed Real-Time Embedded Systems

    Distributed real-time embedded systems have stringent requirements for key performance properties, such as end-to-end timeliness and reliability, in order to operate properly. In recent years, with the continuously decreasing feature size and increasing demand for computation capabilities, today's real-time embedded systems face an increasing probability of overheating and even thermal...

    Provided By University of Tennessee

  • White Papers // Jun 2010

    Virtual Batching: Request Batching for Energy Conservation in Virtualized Servers

    Many power management strategies have been proposed for enterprise servers based on Dynamic Voltage and Frequency Scaling (DVFS), but those solutions cannot further reduce the energy consumption of a server when the server processor is already at the lowest DVFS level and the server utilization is still low (e.g., 5%...

    Provided By University of Tennessee

  • White Papers // Jun 2010

    Dynamic Duty Cycle Control for End-to-End Delay Guarantees in Wireless Sensor Networks

    It is well known that periodically putting nodes into sleep can effectively save energy in wireless sensor networks, at the cost of increased communication delays. However, most existing work mainly focuses on static sleep scheduling, which cannot guarantee the desired delay when the network conditions change dynamically. In many applications...

    Provided By University of Tennessee

  • White Papers // May 2010

    Mean Time to Meaningless: MTTDL, Markov Models, and Storage System Reliability

    Mean Time To Data Loss (MTTDL) has been the standard reliability metric in storage systems for more than 20 years. MTTDL represents a simple formula that can be used to compare the reliability of small disk arrays and to perform comparative trending analyses. The MTTDL metric is often misused, with...

    Provided By University of Tennessee

  • White Papers // Apr 2010

    Alerts Visualization and Clustering in Network-Based Intrusion Detection

    Today's Intrusion detection systems when deployed on a busy network overload the network with huge number of alerts. This behavior of producing too much raw information makes it less effective. The authors propose a system which takes both raw data and Snort alerts to visualize and analyze possible intrusions in...

    Provided By University of Tennessee

  • White Papers // Apr 2010

    Coordinated Energy Management in Virtualized Data Centers

    Energy management in large-scale virtualized data centers has become increasingly important. In this paper, the authors first study the data center workload characteristics based on a large data trace, which includes CPU workload data of 5,416 servers in more than 10 data centers during a one-week period. Informed by the...

    Provided By University of Tennessee

  • White Papers // Mar 2010

    Compressed Meter Reading for Delay-Sensitive and Secure Load Report in Smart Grid

    It is a key task in smart grid to send the readings of smart meters to an Access Point (AP) in a wireless manner. The requirements of scalability, realtimeness and security make the wireless meter reading highly challenging. On assuming that the number of smart meters is large and the...

    Provided By University of Tennessee

  • White Papers // Feb 2010

    Cloud Service Reliability: Modeling and Analysis

    Cloud computing is a recently developed new technology for complex systems with massive scale service sharing, which is different from the resource sharing of the grid computing systems. Cloud reliability analysis and modeling are not easy tasks because of the complexity and large scale of the system. This paper systematically...

    Provided By University of Tennessee

  • White Papers // Feb 2010

    Minimum Transmission Power Configuration in Real-Time Sensor Networks With Overlapping Channels

    Multi-channel communications can effectively reduce channel competition and interferences in a wireless sensor network, and thus achieve increased throughput and improved end-to-end delay guarantees with reduced power consumption. However, existing work relies only on a small number of orthogonal channels, resulting in degraded performance when a large number of data...

    Provided By University of Tennessee

  • White Papers // Jan 2010

    A Fast and Stable Incremental Clustering Algorithm

    Clustering is a pivotal building block in many data mining applications and in machine learning in general. Most clustering algorithms in the literature pertain to off-line (or batch) processing, in which the clustering process repeatedly sweeps through a set of data samples in an attempt to capture its underlying structure...

    Provided By University of Tennessee

  • White Papers // Dec 2009

    Hierarchical Utilization Control for Real-Time and Resilient Power Grid

    Blackouts in the daily life can be disastrous with enormous economic loss. Blackouts usually occur when appropriate corrective actions are not effectively taken for an initial contingency, resulting in a cascade failure. Therefore, it is critical to complete those tasks that are running power grid computing algorithms in the Energy...

    Provided By University of Tennessee

  • White Papers // Dec 2009

    On Controllability and Feasibility of Utilization Control in Distributed Real-Time Systems

    Feedback control techniques have recently been applied to a variety of real-time systems. However, a fundamental issue that was left out is guaranteeing system controllability and the feasibility of applying feedback control to such systems. No control algorithms can effectively control a system which itself is uncontrollable or infeasible. In...

    Provided By University of Tennessee

  • White Papers // Dec 2009

    Exploiting Overlapping Channels for Minimum Power Configuration in Real-Time Sensor Networks

    Multi-channel communications can effectively reduce channel competition and interferences in a wireless sensor network, and thus achieve increased throughput and improved end-to-end delay guarantees with reduced power consumption. However, existing work relies only on a small number of orthogonal channels, resulting in degraded performance when a large number of data...

    Provided By University of Tennessee

  • White Papers // Aug 2008

    A Performance Comparison of Open-Source Erasure Coding Libraries for Storage Applications

    Recent years have seen surge of erasure codes in preventing data loss in storage systems composed of multiple disks. Storage companies such as Cleversafe, Data Domain, Network Appliance and Panasas are offering products that use erasure codes for data availability. Technology majors like HP, IBM and Microsoft are performing active...

    Provided By University of Tennessee

  • White Papers // Apr 2009

    Cloud Computing and Software Services: Theory and Technique

    Distributed computing can be daunting even for experienced programmers. Although many projects have been created to facilitate developing distributed applications, they are often quite complex in themselves. While many scientific applications could benefit from distributed computing, the complexity of the programming models can be a high barrier to entry, especially...

    Provided By University of Tennessee

  • White Papers // Dec 2009

    SHIP: Scalable Hierarchical Power Control for Large-Scale Data Centers

    In today's data centers, precisely controlling server power consumption is an essential way to avoid system failures caused by power capacity overload or overheating due to increasingly high server density. While various power control strategies have been recently proposed, existing solutions are not scalable to control the power consumption of...

    Provided By University of Tennessee

  • White Papers // Feb 2010

    Cloud Service Reliability: Modeling and Analysis

    Cloud computing is a recently developed new technology for complex systems with massive scale service sharing, which is different from the resource sharing of the grid computing systems. Cloud reliability analysis and modeling are not easy tasks because of the complexity and large scale of the system. This paper systematically...

    Provided By University of Tennessee

  • White Papers // Oct 2010

    Integrating Utilization Control With Task Consolidation for Power Optimization in Multi-Core Real-Time Systems

    Since multi-core processors have become a primary trend in processor development, new scheduling algorithms are needed to minimize power consumption while achieving the desired timeliness guarantees for multi-core (and many-core) real-time embedded systems. Although various power/energy efficient scheduling algorithms have recently been proposed, existing studies may have degraded runtime performance...

    Provided By University of Tennessee

  • White Papers // Dec 2009

    Hierarchical Utilization Control for Real-Time and Resilient Power Grid

    Blackouts in the daily life can be disastrous with enormous economic loss. Blackouts usually occur when appropriate corrective actions are not effectively taken for an initial contingency, resulting in a cascade failure. Therefore, it is critical to complete those tasks that are running power grid computing algorithms in the Energy...

    Provided By University of Tennessee

  • White Papers // Dec 2009

    On Controllability and Feasibility of Utilization Control in Distributed Real-Time Systems

    Feedback control techniques have recently been applied to a variety of real-time systems. However, a fundamental issue that was left out is guaranteeing system controllability and the feasibility of applying feedback control to such systems. No control algorithms can effectively control a system which itself is uncontrollable or infeasible. In...

    Provided By University of Tennessee

  • White Papers // Oct 2010

    Adaptive Power Control With Online Model Estimation for Chip Multiprocessors

    As Chip Multiprocessors (CMPs) become the main trend in processor development, various power and thermal management strategies have recently been proposed to optimize system performance while controlling the power or temperature of a CMP chip to stay below a constraint. The availability of per-core DVFS (Dynamic Voltage and Frequency Scaling)...

    Provided By University of Tennessee

  • White Papers // Dec 2009

    Exploiting Overlapping Channels for Minimum Power Configuration in Real-Time Sensor Networks

    Multi-channel communications can effectively reduce channel competition and interferences in a wireless sensor network, and thus achieve increased throughput and improved end-to-end delay guarantees with reduced power consumption. However, existing work relies only on a small number of orthogonal channels, resulting in degraded performance when a large number of data...

    Provided By University of Tennessee

  • White Papers // Jun 2010

    Dynamic Thermal and Timeliness Guarantees for Distributed Real-Time Embedded Systems

    Distributed real-time embedded systems have stringent requirements for key performance properties, such as end-to-end timeliness and reliability, in order to operate properly. In recent years, with the continuously decreasing feature size and increasing demand for computation capabilities, today's real-time embedded systems face an increasing probability of overheating and even thermal...

    Provided By University of Tennessee

  • White Papers // Dec 2009

    Power-Efficient Response Time Guarantees for Virtualized Enterprise Servers

    Both power and performance are important concerns for enterprise data centers. While various management strategies have been developed to effectively reduce server power consumption by transitioning hardware components to lower-power states, they cannot be directly applied to today's data centers that rely on virtualization technologies. Virtual machines running on the...

    Provided By University of Tennessee

  • White Papers // Oct 2010

    Cache-Aware Utilization Control for Energy-Efficient Multi-Core Real-Time Systems

    Multi-core processors are anticipated to become a major development platform for real-time systems. However, existing power management algorithms are not designed to sufficiently utilize the features available in many multi-core processors, such as shared L2 caches and per-core DVFS, to effectively minimize processor energy consumption while providing real-time guarantees. In...

    Provided By University of Tennessee

  • White Papers // Nov 2009

    Dynamic Power Partitioning and Control for Performance Optimization in Chip Multiprocessors

    Since power consumption has become a major constraint for the further throughput improvement of Chip MultiProcessors (CMPs), a key challenge is to optimize the performance of a CMP within a power budget limited by the CMP's cooling, packaging, and power supply capacities. Most existing solutions rely solely on Dynamic Voltage...

    Provided By University of Tennessee

  • White Papers // Nov 2009

    Coordinating Processor and Main Memory for Server Power Capping

    With the number of high-density servers in data centers rapidly increasing, power capping with performance optimization has become a key challenge to gain a high return on investment by accommodating the maximized number of servers allowed by the limited power supply and cooling facilities. Various power capping solutions have been...

    Provided By University of Tennessee

  • White Papers // Feb 2010

    Minimum Transmission Power Configuration in Real-Time Sensor Networks With Overlapping Channels

    Multi-channel communications can effectively reduce channel competition and interferences in a wireless sensor network, and thus achieve increased throughput and improved end-to-end delay guarantees with reduced power consumption. However, existing work relies only on a small number of orthogonal channels, resulting in degraded performance when a large number of data...

    Provided By University of Tennessee

  • White Papers // Dec 2009

    Exploring Power-Performance Tradeoffs in Database Systems

    With the total energy consumption of computing systems increasing in a steep rate, much attention has been paid to the design of energy-efficient computing systems and applications. So far, database system design has focused on improving performance of query processing. The objective of this study is to experimentally explore the...

    Provided By University of Tennessee

  • White Papers // Sep 2009

    Achieving Fair or Differentiated Cache Sharing in Power-Constrained Chip Multiprocessors

    Limiting the peak power consumption of Chip Multi Processors (CMPs) has recently received a lot of attention. In order to enable chip-level power capping, the peak power consumption of on-chip L2 caches in a CMP often needs to be constrained by dynamically transitioning selected cache banks into low-power modes. However,...

    Provided By University of Tennessee

  • White Papers // Dec 2009

    Co-Con: Coordinated Control of Power and Application Performance for Virtualized Server Clusters

    Today's data centers face two critical challenges. First, various customers need to be assured by meeting their required service-level agreements such as response time and throughput. Second, server power consumption must be controlled in order to avoid failures caused by power capacity overload or system overheating due to increasing high...

    Provided By University of Tennessee

  • White Papers // Dec 2009

    Integrated Control of Matching Delay and CPU Utilization in Information Dissemination Systems

    The demand for high performance information dissemination is increasing in many applications, such as ecommerce and security alerting systems. These applications usually require that the desired information be matched between sources and sinks based on established subscriptions in a timely manner while a maximal system throughput be achieved to find...

    Provided By University of Tennessee

  • White Papers // Jun 2010

    Virtual Batching: Request Batching for Energy Conservation in Virtualized Servers

    Many power management strategies have been proposed for enterprise servers based on Dynamic Voltage and Frequency Scaling (DVFS), but those solutions cannot further reduce the energy consumption of a server when the server processor is already at the lowest DVFS level and the server utilization is still low (e.g., 5%...

    Provided By University of Tennessee

  • White Papers // Jun 2010

    Dynamic Duty Cycle Control for End-to-End Delay Guarantees in Wireless Sensor Networks

    It is well known that periodically putting nodes into sleep can effectively save energy in wireless sensor networks, at the cost of increased communication delays. However, most existing work mainly focuses on static sleep scheduling, which cannot guarantee the desired delay when the network conditions change dynamically. In many applications...

    Provided By University of Tennessee

  • White Papers // Dec 2009

    Power-Aware CPU Utilization Control for Distributed Real-Time Systems

    CPU utilization control has recently been demonstrated to be an effective way of meeting end-to-end deadlines for distributed real-time systems running in unpredictable environments. However, current research on utilization control focuses exclusively on task rate adaptation, which cannot effectively handle rate saturation and discrete task rates. Since the CPU utilization...

    Provided By University of Tennessee

  • White Papers // Sep 2010

    Power Optimization With Performance Assurance for Multi-Tier Applications in Virtualized Data Centers

    Modern data centers must provide performance assurance for complex system software such as multi-tier web applications. In addition, the power consumption of data centers needs to be minimized to reduce operating costs and avoid system overheating. Various power-efficient performance management strategies have been proposed based on Dynamic Voltage and Frequency...

    Provided By University of Tennessee

  • White Papers // Dec 2009

    Cluster-Level Feedback Power Control for Performance Optimization

    Power control is becoming a key challenge for effectively operating a modern data center. In addition to reducing operating costs, precisely controlling power consumption is an essential way to avoid system failures caused by power capacity overload or overheating due to increasing high server density. Control-theoretic techniques have recently shown...

    Provided By University of Tennessee

  • White Papers // Mar 2011

    Towards Optimal Sensor Placement for Hot Server Detection in Data Centers

    Recent studies have shown that a significant portion of the total energy consumption of many data centers is caused by the inefficient operation of their cooling systems. Without effective thermal monitoring with accurate location information, the cooling systems often use unnecessarily low temperature set points to overcool the entire room,...

    Provided By University of Tennessee

  • White Papers // Apr 2010

    Coordinated Energy Management in Virtualized Data Centers

    Energy management in large-scale virtualized data centers has become increasingly important. In this paper, the authors first study the data center workload characteristics based on a large data trace, which includes CPU workload data of 5,416 servers in more than 10 data centers during a one-week period. Informed by the...

    Provided By University of Tennessee

  • White Papers // Jan 2011

    Effective VM Sizing in Virtualized Data Centers

    In this paper, the authors undertake the problem of server consolidation in virtualized data centers from the perspective of approximation algorithms. They formulate server consolidation as a stochastic bin packing problem, where the server capacity and an allowed server overflow probability p are given, and the objective is to assign...

    Provided By University of Tennessee

  • White Papers // Aug 2012

    Joint Congestion Control and Routing Subject to Dynamic Interruptions in Cognitive Radio Networks

    Cognitive radio networks suffer from dynamic interruptions from primary users. The joint congestion control and routing are tackled using stochastic control techniques. Centralized dynamic programming is applied for the primal optimization, which provides a performance upper bound. Q-learning is applied when the primary user knowledge is unknown. Dual optimization based...

    Provided By University of Tennessee

  • White Papers // Jan 2011

    A Progressive Approach to Distributed Multiple Target Detection in Sensor Networks

    In this paper, the authors study the multiple target detection problem in sensor networks. Due to the resource limitations of sensor networks, the multiple target detection approach has to be energy-efficient and bandwidth-efficient. The existing centralized solutions cannot satisfy these requirements. They present a progressive detection approach based on the...

    Provided By University of Tennessee

  • White Papers // Dec 2010

    R-Kernel: An Operating System Foundation for Highly Reliable Networked Embedded Systems

    In this paper, the authors present r-kernel, an operating system kernel enhancement specifically designed to improve software reliability in networked embedded systems. The key novelty of r-kernel lies in that it exploits the time dimension of software execution to improve robustness. Specifically, r-kernel keeps track of the execution of applications...

    Provided By University of Tennessee

  • White Papers // Apr 2012

    Efficient and Secure Wireless Communications for Advanced Metering Infrastructure in Smart Grids

    An experiment is carried out to measure the power consumption of households. The analysis on the real measurement data shows that the significant change of power consumption arrives in a Poisson manner. Based on this experiment, a novel wireless communication scheme is proposed for the Advanced Metering Infrastructure (AMI) in...

    Provided By University of Tennessee

  • White Papers // Jan 2012

    Fine-Grained Private Matching for Proximity-Based Mobile Social Networking

    Proximity-based Mobile Social Networking (PMSN) refers to the social interaction among physically proximate mobile users directly through the Bluetooth/WiFi interfaces on their smartphones or other mobile devices. It becomes increasingly popular due to the recently explosive growth of smartphone users. Profile matching means two users comparing their personal profiles and...

    Provided By University of Tennessee

  • White Papers // Oct 2011

    Collaborative Scheduling in Highly Dynamic Environments Using Error Inference

    Energy constraint is a critical hurdle hindering the practical deployment of long-term wireless sensor network applications. Turning off (i.e., duty cycling) sensors could reduce energy consumption, however at the cost of low sensing fidelity due to sensing gaps introduced. Existing techniques have studied how to collaboratively reduce the sensing gap...

    Provided By University of Tennessee

  • White Papers // Jul 2014

    Multi-Elimination ILU Preconditioners on GPUs

    Iterative solvers for sparse linear systems often benefit from using preconditioners. While there are implementations for many iterative methods that leverage the computing power of accelerators, porting the latest developments in preconditioners to accelerators has been challenging. In this paper, the authors develop a self-adaptive multi-elimination preconditioner for Graphics Processing...

    Provided By University of Tennessee

  • White Papers // Jul 2014

    Optimizing Krylov Subspace Solvers on Graphics Processing Units

    Krylov subspace solvers are often the method of choice when solving sparse linear systems iteratively. At the same time, hardware accelerators such as Graphics Processing Units (GPUs) continue to offer significant floating point performance gains for matrix and vector computations through easy-to-use libraries of computational kernels. However, as these libraries...

    Provided By University of Tennessee

  • White Papers // Feb 2011

    AONT-RS: Blending Security and Performance in Dispersed Storage Systems

    Dispersing files across multiple sites yields a variety of obvious benefits, such as availability, proximity and reliability. Less obviously, it enables security to be achieved without relying on encryption keys. Standard approaches to dispersal either achieve very high security with correspondingly high computational and storage costs, or low security with...

    Provided By University of Tennessee

  • White Papers // May 2010

    Mean Time to Meaningless: MTTDL, Markov Models, and Storage System Reliability

    Mean Time To Data Loss (MTTDL) has been the standard reliability metric in storage systems for more than 20 years. MTTDL represents a simple formula that can be used to compare the reliability of small disk arrays and to perform comparative trending analyses. The MTTDL metric is often misused, with...

    Provided By University of Tennessee

  • White Papers // Dec 2010

    Learning Restricted Bayesian Network Structures

    Bayesian networks are basic graphical models, used widely both in statistics and artificial intelligence. These statistical models of conditional independence structure are described by acyclic directed graphs whose nodes correspond to (random) variables in consideration. A quite important topic is the learning of Bayesian network structures, which is determining the...

    Provided By University of Tennessee

  • White Papers // Apr 2011

    Cache-Aware Utilization Control for Energy Efficiency in Multi-Core Real-Time Systems

    Multi-core processors are anticipated to become a major development platform for real-time systems. However, existing power management algorithms are not designed to sufficiently utilize the features available in many multi-core processors, such as shared L2 caches and per-core DVFS, to effectively minimize processor energy consumption while providing real-time guarantees. In...

    Provided By University of Tennessee

  • White Papers // Oct 2010

    Combating False Reports for Secure Networked Control in Smart Grid Via Trustiness Evaluation

    Smart grid, equipped with modern communication infrastructures, is subject to possible cyber attacks. Particularly, false report attacks which replace the sensor reports with fraud ones may cause the instability of the whole power grid or even result in a large area blackout. In this paper, a trustiness system is introduced...

    Provided By University of Tennessee