North Carolina State University

Displaying 41-80 of 258 results

  • White Papers // Jun 2012

    CuNesl: Compiling Nested Data-Parallel Languages for SIMT Architectures

    Data-parallel languages feature fine-grained parallel primitives that can be supported by compilers targeting modern many-core architectures where data parallelism must be exploited to fully utilize the hardware. Previous research has focused on converting data-parallel languages for SIMD (Single Instruction Multiple Data) architectures. However, directly applying them to today's SIMT (Single...

    Provided By North Carolina State University

  • White Papers // Jun 2012

    From Glauber Dynamics to Metropolis Algorithm: Smaller Delay in Optimal CSMA

    Since the seminal work by Tassiulas and Ephremides on throughput-optimal scheduling, referred to as Max-Weight, a huge array of research has been made to develop distributed MAC scheduling with high performance guarantee and low complexity. The tradeoff between complexity and efficiency has been, however, observed in many cases, or even...

    Provided By North Carolina State University

  • White Papers // May 2012

    Enabling Adaptive Rate and Relay Selection for 802.11 Mobile Ad Hoc Networks

    Mobile Ad hoc NETworks (MANETs) are self-configuring wireless networks that lack permanent infrastructure and are formed among mobile nodes on demand. Rapid node mobility results in dramatic channel variation, or fading, that degrades MANET performance. Employing Channel State Information (CSI) at the transmitter can improve the throughput of routing and...

    Provided By North Carolina State University

  • White Papers // May 2012

    An Algorithm for Joint Guidance and Power Control for Electric Vehicles in the Smart Grid

    A massive amount of energy consumption currently stems from the transportation sector. Therefore, improvements in power usage by commuting vehicles are being studied and becoming an increasingly popular research topic. In particular, there is a growing need to model the envisioned smart infrastructure, including charging stations, some of which might...

    Provided By North Carolina State University

  • White Papers // May 2012

    Geo-Dissemination in Vehicular Ad Hoc Networks

    Vehicular Ad hoc NETworks (VANETs) aim to improve road safety and convenience through vehicle-to-vehicle and vehicle-to-roadside communications. Traffic information and accident warnings are often disseminated to vehicles in certain areas where driving could be affected by hazardous situations. Such message dissemination with destinations confined in specific geographic regions is referred...

    Provided By North Carolina State University

  • White Papers // May 2012

    Balancing Network Connectivity and the Life-Time of Sensors Through Percolation and Consensus

    Due to replacement infeasibility, methods to extend the life-time of sensors have been an issue in Wireless Sensor Networks (WSNs) and these should consider network connectivity simultaneously. Controlling the sleep/awake of sensors is one simple way to reduce their energy consumption. However, this causes a network connectivity degradation by varying...

    Provided By North Carolina State University

  • White Papers // May 2012

    On the Connectivity of Large Multi-Channel Cognitive Radio Networks

    Cognitive Radio Networks (CRNs) have become promising network components to improve spectrum utilization efficiency, where secondary (unlicensed) users exploit spectrum opportunistically without interfering with the coexisting primary users. A challenging yet open question is how to ensure that information can be disseminated to the entire CRN, which is a prerequisite...

    Provided By North Carolina State University

  • White Papers // May 2012

    Communication Theory Perspective on Antenna Selection for Compact Transceivers

    Traditional antenna selection applied to MIMO systems ignores the presence of unselected (or inactive) antennas. However, compact arrays offer a unique advantage in that mutual coupling can be exploited to improve the system performance. Previous studies on selection with coupling have not considered the effects of the inactive-antenna terminations and...

    Provided By North Carolina State University

  • White Papers // May 2012

    Fundamental Capacity Limits on Compact MIMO-OFDM Systems

    The authors undertake an information-theoretic approach to characterize the optimal design of a broadband multi-antenna system in the presence of mutual coupling. It was shown recently that mutual coupling effectively decomposes otherwise spectrally identical spatial modes of an antenna array into spectrally non-identical eigen-modes. They shall use Shannon's information theory...

    Provided By North Carolina State University

  • White Papers // May 2012

    Understanding the Limits of Capacity Sharing in CMP Private Caches

    Chip Multi Processor (CMP) systems present interesting design challenges at the lower levels of the cache hierarchy. Private L2 caches allow easier processor-cache design reuse, thus scaling better than a system with a shared L2 cache, while offering better performance isolation and lower access latency. While some private cache management...

    Provided By North Carolina State University

  • White Papers // May 2012

    Efficient Intranode Communication in GPU-Accelerated Systems

    Current implementations of MPI are unaware of accelerator memory (i.e., GPU device memory) and require programmers to explicitly move data between memory spaces. This approach is inefficient, especially for intranode communication where it can result in several extra copy operations. In this paper, the authors integrate GPU-awareness into a popular...

    Provided By North Carolina State University

  • White Papers // Apr 2012

    PREPARE: Predictive Performance Anomaly Prevention for Virtualized Cloud Systems

    Virtualized cloud systems are prone to performance anomalies due to various reasons such as resource contentions, software bugs, and hardware failures. In this paper, the authors present a novel PREdictive Performance Anomaly pREvention (PREPARE) system that provides automatic performance anomaly prevention for virtualized cloud computing infrastructures. PREPARE integrates online anomaly...

    Provided By North Carolina State University

  • White Papers // Apr 2012

    Beyond Random Walk and Metropolis-Hastings Samplers: Why You Should Not Backtrack for Unbiased Graph Sampling

    Graph sampling via crawling has been actively considered as a generic and important tool for collecting uniform node samples so as to consistently estimate and uncover various characteristics of complex networks. The so-called Simple Random Walk with re-weighting (SRW-rw) and Metropolis-Hastings (MH) algorithm have been popular in the literature for...

    Provided By North Carolina State University

  • White Papers // Apr 2012

    Advertising Cached Contents in the Control Plane: Necessity and Feasibility

    A key feature of Information-Centric Networking architectures is universal caching where anyone can cache any content and users can obtain the content from anywhere as long as the content itself is intact. This powerful feature benefits the content providers, the Internet Service Providers (ISPs) as well as end users since...

    Provided By North Carolina State University

  • White Papers // Mar 2012

    Inferring Method Specifications From Natural Language API Descriptions

    Application Programming Interface (API) documents are a typical way of describing legal usage of reusable software libraries, thus facilitating software reuse. However, even with such documents, developers often overlook some documents and build software systems that are inconsistent with the legal usage of those libraries. Existing software verification tools require...

    Provided By North Carolina State University

  • White Papers // Mar 2012

    Making Exceptions on Exception Handling

    The exception-handling mechanism has been widely adopted to deal with exception conditions that may arise during program executions. To produce high-quality programs, developers are expected to handle these exception conditions and take necessary recovery or resource-releasing actions. Failing to handle these exception conditions can lead to not only performance degradation,...

    Provided By North Carolina State University

  • White Papers // Mar 2012

    Fault Resilient Real-Time Design for NoC Architectures

    Performance and time to market requirements cause many real-time designers to consider Components, Off The Shelf (COTS) for real-time cyber-physical systems. Massive multi-core embedded processors with Network-on-Chip (NoC) designs to facilitate core-to-core communication are becoming common in COTS. These architectures benefit real-time scheduling, but they also pose predictability challenges. in...

    Provided By North Carolina State University

  • White Papers // Mar 2012

    Low ContentionMapping of Real-Time Tasks onto a TilePro 64 Core Processor

    Predictability of task execution is paramount for real-time systems so that upper bounds of execution times can be determined via static timing analysis. Static timing analysis on Network-on-Chip (NoC) processors may result in unsafe underestimations when the underlying communication paths are not considered. This stems from contention on the underlying...

    Provided By North Carolina State University

  • White Papers // Mar 2012

    Low Contention Mapping of Real-Time Tasks onto a TilePro 64 Core Processor

    Predictability of task execution is paramount for real-time systems so that upper bounds of execution times can be determined via static timing analysis. Static timing analysis on Network-on-Chip (NoC) processors may result in unsafe underestimations when the underlying communication paths are not considered. This stems from contention on the underlying...

    Provided By North Carolina State University

  • White Papers // Mar 2012

    Isolating Failure-Inducing Combinations in Combinatorial Testing Using Test Augmentation and Classification

    Combinatorial Testing (CT) is a systematic way of sampling input parameters of the Software Under Test (SUT). A t-way combinatorial test set can exercise all behaviors of the SUT caused by interactions between t input parameters or less. Although combinatorial testing can provide fault detection capability, it is often desirable...

    Provided By North Carolina State University

  • White Papers // Mar 2012

    Gossip-Based Information Spreading in Mobile Networks

    Mobile networks receive increasing research interest recently due to their increasingly wide applications in various areas; Mobile Ad hoc NETworks (MANET) and Vehicular Ad hoc NETworks (VANET) are two prominent examples. Mobility introduces challenges as well as opportunities: it is known to improve the network throughput as shown in. In...

    Provided By North Carolina State University

  • White Papers // Mar 2012

    Energy Efficient Iterative Waterfilling for the MIMO Broadcasting Channels

    Optimizing Energy Efficiency (EE) for the MIMO Broadcasting Channels (BC) is considered in this paper, where a practical power model is taken into account. Although the EE of the MIMO BC is non-concave, the authors reformulate it as a quasi-concave function based on the uplink-downlink duality. After that, an energy...

    Provided By North Carolina State University

  • White Papers // Mar 2012

    Packet Aggregation Based Back-Pressure Scheduling in Multi-Hop Wireless Networks

    The back-pressure based scheduling policy originally proposed by Tassiulas et al. in has shown the potential of solving many fairness and network utilization related problems of wireless multi-hop networks. Recently, the scheduling policy has been adapted in random medium access protocols such as CSMA/CA using prioritization of MAC layer transmissions....

    Provided By North Carolina State University

  • White Papers // Mar 2012

    Dissecting Android Malware: Characterization and Evolution

    The popularity and adoption of Smartphones has greatly stimulated the spread of mobile malware, especially on the popular platforms such as Android. In light of their rapid growth, there is a pressing need to develop effective solutions. However, their defense capability is largely constrained by the limited understanding of these...

    Provided By North Carolina State University

  • White Papers // Feb 2012

    Evaluating Dynamics and Bottlenecks of Memory Collaboration in Cluster Systems

    With the fast development of highly-integrated distributed systems (cluster systems), designers face interesting memory hierarchy design choices while attempting to avoid the notorious disk swapping. Swapping to the free remote memory through Memory Collaboration has demonstrated its cost-effectiveness compared to over-provisioning the cluster for peak load requirements. Recent memory collaboration...

    Provided By North Carolina State University

  • White Papers // Feb 2012

    Locality Principle Revisited: A Probability-Based Quantitative Approach

    This paper revisits the fundamental concept of the locality of references and proposes to quantify it as a conditional probability: in an address stream, given the condition that an address is accessed, how likely the same address (temporal locality) or an address within its neighborhood (spatial locality) will be accessed...

    Provided By North Carolina State University

  • White Papers // Feb 2012

    CPU-Assisted GPGPU on Fused CPU-GPU Architectures

    This paper presents a novel approach to utilize the CPU resource to facilitate the execution of GPGPU programs on fused CPU-GPU architectures. In the authors' model of fused architectures, the GPU and the CPU are integrated on the same die and share the on-chip L3 cache and off-chip memory, similar...

    Provided By North Carolina State University

  • White Papers // Feb 2012

    Data Sharing in MultiThreaded Applications and Its Impact on Chip Design

    Analytical modeling is becoming an increasingly important technique used in the design of chip multiprocessors. Most such models assume multi-programmed workload mixes and either ignore or oversimplify the behavior of multi-threaded applications. In particular, data sharing observed in multi-threaded applications, and its impact on chip design decisions, has not been...

    Provided By North Carolina State University

  • White Papers // Feb 2012

    On the Capacity Region for Cognitive Multiple Access Over White Space Channels

    Cognitive Radio (CR) has stirred great interest with its potential to exploit the already scarce spectrum resource. The Cognitive Multiple Access Channels (CogMAC) are commonly seen in many applications, such as the Cognitive Radio Sensor Networks (CRSN), and the 802.22 cognitive Wireless Regional Area Networks (WRAN). In this paper, the...

    Provided By North Carolina State University

  • White Papers // Jan 2012

    ScalaBenchGen: Auto-Generation of Communication Benchmarks Traces

    Benchmarks are essential for evaluating HPC hardware and software for petascale machines and beyond. But benchmark creation is a tedious manual process. As a result, benchmarks tend to lag behind the development of complex scientific codes. This work contributes an automated approach to the creation of communication benchmarks. Given an...

    Provided By North Carolina State University

  • White Papers // Jan 2012

    BitTrickle: Defending Against Broadband and High-Power Reactive Jamming Attacks

    Reactive jamming is not only cost effective, but also hard to track and remove due to its intermittent jamming behaviors. Frequency Hopping Spread Spectrum (FHSS) and Direct Sequence Spread Spectrum (DSSS) have been widely used to defend against jamming attacks. However, both will fail if the jammer jams all frequency...

    Provided By North Carolina State University

  • White Papers // Jan 2012

    Enhanced Wireless Channel Authentication Using Time-Synched Link Signature

    Wireless link signature is a physical layer authentication mechanism, which uses the unique wireless channel characteristics between a transmitter and a receiver to provide authentication of wireless channels. A vulnerability of existing link signature schemes has been identified by introducing a new attack, called mimicry attack. To defend against the...

    Provided By North Carolina State University

  • White Papers // Jan 2012

    Efficient, Compromise Resilient and Append-Only Cryptographic Schemes for Secure Audit Logging

    Due to the forensic value of audit logs, it is vital to provide compromise resiliency and append-only properties in a logging system to prevent active attackers. Unfortunately, existing symmetric secure logging schemes are not publicly verifiable and cannot address applications that require public auditing (e.g., public financial auditing), besides being...

    Provided By North Carolina State University

  • White Papers // Jan 2012

    Hey, You, Get Off of My Market: Detecting Malicious Apps in Official and Alternative Android Markets

    In this paper, the authors present a systematic study for the detection of malicious applications (or apps) on popular Android Markets. To this end, they first propose a permission-based behavioral foot-printing scheme to detect new samples of known Android malware families. Then they apply a heuristics-based filtering scheme to identify...

    Provided By North Carolina State University

  • White Papers // Jan 2012

    Internet Service Tiering as a Market Segmentation Strategy

    The authors consider Internet broadband access as an elastic service whose value varies across segments of the user population. They show that introducing multiple tiers of service can be an effective market segmentation strategy that can lead to an increase of profits for the ISP. They also develop an efficient...

    Provided By North Carolina State University

  • White Papers // Jan 2012

    A Step Toward Realistic Performance Evaluation of High-Speed TCP Variants

    In this paper, the authors' work on designing realistic evaluation suites for testing high-speed TCP variants. They have created an experimental network model that captures some of the complex characteristics of propagation delays and background traffic. They use their network model to evaluate a large collection of recently proposed TCPs...

    Provided By North Carolina State University

  • White Papers // Jan 2012

    Fundamental Limits of Passive Attacks on Wireless Link Signatures

    The goal of this paper is to gain a fundamental understanding of the potential vulnerability of existing wireless link schemes subject to passive eavesdropping and inference. From the adversary's perspective, the feasibility and fundamental limit of this new attack is explored. In addition, how the theoretical results are instantiated in...

    Provided By North Carolina State University

  • White Papers // Nov 2011

    Systematic Detection of Capability Leaks in Stock Android Smartphones

    Recent years have witnessed a meteoric increase in the adoption of Smartphones. To manage information and features on such phones, Android provides a permission-based security model that requires each application to explicitly request permissions before it can be installed to run. In this paper, the authors analyze eight popular Android...

    Provided By North Carolina State University

  • White Papers // Nov 2011

    Time-Traveling Forensic Analysis of VM-Based High-Interaction Honeypots

    Honeypots have proven to be an effective tool to capture computer intrusions (or malware infections) and analyze their exploitation techniques. However, forensic analysis of compromised honeypots is largely an ad-hoc and manual process. In this paper, the authors propose Timescope, a system that applies and extends recent advances in deterministic...

    Provided By North Carolina State University

  • White Papers // Oct 2011

    AutoGeneration of Communication Benchmark Traces

    Benchmarks are essential for evaluating HPC hardware and software for petascale machines and beyond. But benchmark creation is a tedious manual process. As a result, benchmarks tend to lag behind the development of complex scientific codes. The authors' paper automates the creation of communication benchmarks. Given an MPI application, they...

    Provided By North Carolina State University

  • White Papers // Jun 2009

    Randomized Differential DSSS: Jamming-Resistant Wireless Broadcast Communication

    Jamming resistance is crucial for applications where reliable wireless communication is required. Spread spectrum techniques such as Frequency Hopping Spread Spectrum (FHSS) and Direct Sequence Spread Spectrum (DSSS) have been used as countermeasures against jamming attacks. Traditional anti-jamming techniques require that senders and receivers share a secret key in order...

    Provided By North Carolina State University

  • White Papers // Apr 2009

    Structured Variational Methods for Distributed Inference: Convergence Analysis and Performance-Complexity Tradeoff

    In this paper, the asymptotic performance of a recently proposed distributed inference framework, structured variational methods, is investigated. The authors first distinguish the intra- and inter-cluster inference algorithms as vertex and edge processes respectively. Their difference is illustrated, and convergence rate is derived for the intra-cluster inference procedure which is...

    Provided By North Carolina State University

  • White Papers // Jan 2009

    Adaptive Quickest Change Detection With Unknown Parameter

    Quickest detection of an abrupt distribution change with an unknown time varying parameter is considered. A novel adaptive approach is proposed to tackle this problem, which is shown to outperform the celebrated Parallel CUSUM Test. Performance is evaluated through theoretical analysis and numerical simulations. Quickest detection is a technique to...

    Provided By North Carolina State University

  • White Papers // Jan 2009

    Structured Variational Methods for Distributed Inference in Wireless Ad Hoc and Sensor Networks

    In this paper, a variational message passing framework is proposed for Markov random fields, which is computationally more efficient and admits wider applicability compared to the belief propagation algorithm. Based on this framework, structured variational methods are explored to take advantage of both the simplicity of variational approximation (for inter-cluster...

    Provided By North Carolina State University

  • White Papers // Jan 2012

    BitTrickle: Defending Against Broadband and High-Power Reactive Jamming Attacks

    Reactive jamming is not only cost effective, but also hard to track and remove due to its intermittent jamming behaviors. Frequency Hopping Spread Spectrum (FHSS) and Direct Sequence Spread Spectrum (DSSS) have been widely used to defend against jamming attacks. However, both will fail if the jammer jams all frequency...

    Provided By North Carolina State University

  • White Papers // Jan 2012

    Enhanced Wireless Channel Authentication Using Time-Synched Link Signature

    Wireless link signature is a physical layer authentication mechanism, which uses the unique wireless channel characteristics between a transmitter and a receiver to provide authentication of wireless channels. A vulnerability of existing link signature schemes has been identified by introducing a new attack, called mimicry attack. To defend against the...

    Provided By North Carolina State University

  • White Papers // Jan 2012

    Efficient, Compromise Resilient and Append-Only Cryptographic Schemes for Secure Audit Logging

    Due to the forensic value of audit logs, it is vital to provide compromise resiliency and append-only properties in a logging system to prevent active attackers. Unfortunately, existing symmetric secure logging schemes are not publicly verifiable and cannot address applications that require public auditing (e.g., public financial auditing), besides being...

    Provided By North Carolina State University

  • White Papers // Apr 2009

    Remote Attestation to Dynamic System Properties: Towards Providing Complete System Integrity Evidence

    Remote attestation of system integrity is an essential part of trusted computing. However, current remote attestation techniques only provide integrity proofs of static properties of the system. To address this problem the authors present a novel remote dynamic attestation system named ReDAS (Remote Dynamic Attestation System) that provides integrity evidence...

    Provided By North Carolina State University

  • White Papers // Apr 2012

    Beyond Random Walk and Metropolis-Hastings Samplers: Why You Should Not Backtrack for Unbiased Graph Sampling

    Graph sampling via crawling has been actively considered as a generic and important tool for collecting uniform node samples so as to consistently estimate and uncover various characteristics of complex networks. The so-called Simple Random Walk with re-weighting (SRW-rw) and Metropolis-Hastings (MH) algorithm have been popular in the literature for...

    Provided By North Carolina State University

  • White Papers // May 2012

    Efficient Intranode Communication in GPU-Accelerated Systems

    Current implementations of MPI are unaware of accelerator memory (i.e., GPU device memory) and require programmers to explicitly move data between memory spaces. This approach is inefficient, especially for intranode communication where it can result in several extra copy operations. In this paper, the authors integrate GPU-awareness into a popular...

    Provided By North Carolina State University

  • White Papers // Apr 2012

    PREPARE: Predictive Performance Anomaly Prevention for Virtualized Cloud Systems

    Virtualized cloud systems are prone to performance anomalies due to various reasons such as resource contentions, software bugs, and hardware failures. In this paper, the authors present a novel PREdictive Performance Anomaly pREvention (PREPARE) system that provides automatic performance anomaly prevention for virtualized cloud computing infrastructures. PREPARE integrates online anomaly...

    Provided By North Carolina State University

  • White Papers // Jul 2011

    IEEE 802.11 Saturation Throughput Analysis in the Presence of Hidden Terminals

    Due to its usefulness and wide deployment, IEEE 802.11 has been the subject of numerous studies but still lacks a complete analytical model. Hidden terminals are common in IEEE 802.11 and cause the degradation of throughput. Despite the importance of the hidden terminal problem, there have been a relatively small...

    Provided By North Carolina State University

  • White Papers // Aug 2012

    Network Virtualization: Technologies, Perspectives, and Frontiers

    Network virtualization refers to a broad set of technologies. Commercial solutions have been offered by the industry for years, while more recently the academic community has emphasized virtualization as an enabler for network architecture research, deployment, and experimentation. The authors review the entire spectrum of relevant approaches with the goal...

    Provided By North Carolina State University

  • White Papers // Aug 2012

    A Fast Path-Based ILP Formulation for Offline RWA in Mesh Optical Networks

    RWA is a fundamental problem in the design and control of optical networks. The authors introduce the concept of symmetric RWA solutions and present a new ILP formulation to construct optimally such solutions. The formulation scales to mesh topologies representative of backbone and regional networks. Numerical results demonstrate that the...

    Provided By North Carolina State University

  • White Papers // Oct 2010

    Demonstration of QoS-Aware Video Streaming Over a Metro-Scale Optical Network Using a Cross-Layer Architectural Design

    QoS-aware video streaming is demonstrated on an optical network using a service-oriented architecture and a NetFPGA-based optical control plane. Dynamic optical power fluctuations are either compensated or the lightpath is rerouted to ensure the QoS. The layered architecture of the current Internet is becoming increasingly strained in supporting the ever-increasing...

    Provided By North Carolina State University

  • White Papers // Jan 2012

    Internet Service Tiering as a Market Segmentation Strategy

    The authors consider Internet broadband access as an elastic service whose value varies across segments of the user population. They show that introducing multiple tiers of service can be an effective market segmentation strategy that can lead to an increase of profits for the ISP. They also develop an efficient...

    Provided By North Carolina State University

  • White Papers // Jul 2009

    A Hierarchical Model for Multigranular Optical Networks

    The authors present a hierarchical algorithm for grooming light-paths into wavebands, and routing wavebands over a network of multi-granular switching nodes. This algorithm focuses on lowering the number of wavelengths W and ports over the network while being conceptually simple, scalable, and consistent with the way networks are operated and...

    Provided By North Carolina State University

  • White Papers // May 2012

    Geo-Dissemination in Vehicular Ad Hoc Networks

    Vehicular Ad hoc NETworks (VANETs) aim to improve road safety and convenience through vehicle-to-vehicle and vehicle-to-roadside communications. Traffic information and accident warnings are often disseminated to vehicles in certain areas where driving could be affected by hazardous situations. Such message dissemination with destinations confined in specific geographic regions is referred...

    Provided By North Carolina State University

  • White Papers // May 2012

    Balancing Network Connectivity and the Life-Time of Sensors Through Percolation and Consensus

    Due to replacement infeasibility, methods to extend the life-time of sensors have been an issue in Wireless Sensor Networks (WSNs) and these should consider network connectivity simultaneously. Controlling the sleep/awake of sensors is one simple way to reduce their energy consumption. However, this causes a network connectivity degradation by varying...

    Provided By North Carolina State University

  • White Papers // May 2012

    On the Connectivity of Large Multi-Channel Cognitive Radio Networks

    Cognitive Radio Networks (CRNs) have become promising network components to improve spectrum utilization efficiency, where secondary (unlicensed) users exploit spectrum opportunistically without interfering with the coexisting primary users. A challenging yet open question is how to ensure that information can be disseminated to the entire CRN, which is a prerequisite...

    Provided By North Carolina State University

  • White Papers // May 2012

    Communication Theory Perspective on Antenna Selection for Compact Transceivers

    Traditional antenna selection applied to MIMO systems ignores the presence of unselected (or inactive) antennas. However, compact arrays offer a unique advantage in that mutual coupling can be exploited to improve the system performance. Previous studies on selection with coupling have not considered the effects of the inactive-antenna terminations and...

    Provided By North Carolina State University

  • White Papers // May 2012

    Fundamental Capacity Limits on Compact MIMO-OFDM Systems

    The authors undertake an information-theoretic approach to characterize the optimal design of a broadband multi-antenna system in the presence of mutual coupling. It was shown recently that mutual coupling effectively decomposes otherwise spectrally identical spatial modes of an antenna array into spectrally non-identical eigen-modes. They shall use Shannon's information theory...

    Provided By North Carolina State University

  • White Papers // Feb 2009

    Lightweight Remote Image Management for Secure Code Dissemination in Wireless Sensor Networks

    Wireless sensor networks are considered ideal candidates for a wide range of applications. It is desirable and sometimes necessary to reprogram sensor nodes through wireless links after they are deployed to remove bugs or add new functionalities. Several approaches (e.g., Seluge, Sluice) have been proposed recently for secure code dissemination...

    Provided By North Carolina State University

  • White Papers // Jun 2009

    ReFormat: Automatic Reverse Engineering of Encrypted Messages

    Automatic protocol reverse engineering has recently received significant attention due to its importance to many security applications. However, previous methods are all limited in analyzing only plain-text communications wherein the exchanged messages are not encrypted. In this paper, the authors propose ReFormat, a system that aims at deriving the message...

    Provided By North Carolina State University

  • White Papers // Aug 2009

    Power Efficient Traffic Grooming in Optical WDM Networks

    Power-awareness in networking attracts more attention as the trends in the energy consumption of the Internet raise growing concerns about the environmental impacts and sustainability of the network expansion. Building energy efficient equipment is definitely an integral part of the solution. However, such a strategy should be complemented with appropriate...

    Provided By North Carolina State University

  • White Papers // Jan 2011

    Using Prime Numbers for Cache Indexing to Eliminate Conflict Misses

    Using alternative cache indexing/hashing functions is a popular technique to reduce conflict misses by achieving a more uniform cache access distribution across the sets in the cache. Although various alternative hashing functions have been demonstrated to eliminate the worst case conflict behavior, no study has really analyzed the pathological behavior...

    Provided By North Carolina State University

  • White Papers // Aug 2010

    First Step Towards Automatic Correction of Firewall Policy Faults

    In this paper, the authors make three major contributions. First, they propose the first comprehensive fault model for firewall policies including five types of faults. For each type of fault, they present an automatic correction technique. Second, they propose the first systematic approach that employs these five techniques to automatically...

    Provided By North Carolina State University

  • White Papers // Jan 2009

    DiffQ: Practical Differential Backlog Congestion Control for Wireless Networks

    Congestion control in wireless multi-hop networks is challenging and complicated because of two reasons. First, interference is ubiquitous and causes loss in the shared medium. Second, wireless multihop networks are characterized by the use of diverse and dynamically changing routing paths. Traditional end point based congestion control protocols are ineffective...

    Provided By North Carolina State University

  • White Papers // Feb 2009

    Guided Path Exploration for Regression Test Generation

    Regression test generation aims at generating a test suite that can detect behavioral differences between the original and the modified versions of a program. Regression test generation can be automated by using Dynamic Symbolic Execution (DSE), a state-of-the-art test generation technique, to generate a test suite achieving high structural coverage....

    Provided By North Carolina State University

  • White Papers // Jul 2009

    The Impact Of Exchange Rate Volatility On Plant-level Investment: Evidence From

    The authors estimate the impact of exchange rate volatility on firms' investment decisions in a developing country setting. Employing plant-level panel data from the Colombian Manufacturing Census, they estimate a dynamic investment equation using the system-GMM estimator developed by Arellano and Bover (1995) and Blundell and Bond (1998). They find...

    Provided By North Carolina State University

  • White Papers // Dec 2010

    A Timed Logic for Modeling and Reasoning About Security Protocols

    Many logical methods are usually considered suitable to express the static properties of security protocols while unsuitable to model dynamic processes or properties. However, a security protocol itself is in fact a dynamic process over time, and sometimes it is important to be able to express time-dependent security properties of...

    Provided By North Carolina State University

  • White Papers // Jan 2011

    The Incremental Deployability of RTT-Based Congestion Avoidance for High Speed TCP Internet Connections

    The research focuses on end-to-end congestion avoidance algorithms that use Round Trip Time (RTT) fluctuations as an indicator of the level of network congestion. The algorithms are referred to as delay-based congestion avoidance or DCA. Due to the economics associated with deploying change within an existing network, the authors are...

    Provided By North Carolina State University

  • White Papers // Jan 2011

    Asymmetric Multiprocessing for Simultaneous Multithreading Processors

    Simultaneous Multithreading (SMT) has become common in commercially available processors with hardware support for dual contexts of execution. However, performance of SMT systems has been disappointing for many applications. Consequently, many SMT systems are operated in a single-context configuration to achieve better average throughput, depending on the application domain. This...

    Provided By North Carolina State University

  • White Papers // Mar 2009

    Feedback-Directed Page Placement for CcNUMA Via Hardware-Generated Memory Traces

    Non-Uniform Memory Architectures with cache coherence (ccNUMA) are becoming increasingly common, not just for large-scale high performance platforms but also in the context of multi-cores architectures. Under ccNUMA, data placement may influence overall application performance significantly as references resolved locally to a processor/core impose lower latencies than remote ones. This...

    Provided By North Carolina State University

  • White Papers // Mar 2011

    Probabilistic Communication and I/O Tracing With Deterministic Replay at Scale

    With today's petascale supercomputers, applications often exhibit low efficiency, such as poor communication and I/O performance that can be diagnosed by analysis tools. However, these tools either produce extremely large trace files that complicate performance analysis, or sacrifice accuracy to collect high-level statistical information using crude averaging. This work contributes...

    Provided By North Carolina State University

  • White Papers // Apr 2011

    Static Task Partitioning for Locked Caches in Multi-Core Real-Time Systems

    Massive multi-core architectures with tens of cores are becoming more prevalent in embedded systems. However, their acceptance in the real-time systems domain is rather low due to challenges in system analysis and predictability. Recent real-time systems research has focused on shared cache architectures. In such systems, tasks across all cores...

    Provided By North Carolina State University

  • White Papers // Jan 2011

    Challenges for Cyber-Physical Systems: Security, Timing Analysis and Soft Error Protection

    The power grid represents a distributed cyber-physical system that is essential to the every-day life. Larger-scale black-outs are known to have a severe economic and safety impact, as historical events have shown. The severity in impact of power outage on the life is increasing continuously as the power distribution grid...

    Provided By North Carolina State University

  • White Papers // May 2010

    Making DRAM Refresh Predictable

    Embedded control systems with hard real-time constraints require that deadlines are met at all times or the system may malfunction with potentially catastrophic consequences. Schedulability theory can assure deadlines for a given task set when periods and Worst-Case Execution Times (WCETs) of tasks are known. While periods are generally derived...

    Provided By North Carolina State University

  • White Papers // Apr 2009

    FREEDM Software Controller Architecture for a Solid State Transformer

    The Future Renewable Electric Energy Delivery and Management (FREEDM) project aims at providing an efficient electric power grid integrating alternative generating sources and storage with existing power systems to facilitate a green energy in a highly distributed and scalable manner. One of the central aspects of the Reliable and Secure...

    Provided By North Carolina State University

  • White Papers // May 2010

    Fault Tolerant Network Routing Through Software Overlays for Intelligent Power Grids

    Control decisions of intelligent devices in critical infrastructure can have a significant impact on human life and the environment. Insuring that the appropriate data is available is crucial in making informed decisions. Such considerations are becoming increasingly important in today's cyber-physical systems that combine computational decision making on the cyber...

    Provided By North Carolina State University