Northwestern University

Displaying 1-40 of 154 results

  • White Papers // Aug 2013

    Scheduled Voltage Scaling for Increasing Lifetime in the Presence of NBTI

    Negative Bias Temperature Instability (NBTI) is a leading reliability concern for Integrated Circuits (ICs). It gradually increases the threshold voltages of PMOS transistors, thereby increasing delay. The authors propose scheduled voltage scaling, a technique that gradually increases the operating voltage of the IC to compensate for NBTI-related performance degradation. Scheduled...

    Provided By Northwestern University

  • White Papers // Apr 2013

    Guarded Execution of Privileged Code in the Guest

    Allowing a guest to have direct, privileged access to hardware can enhance its performance and functionality. Privileged access to hardware and the VMM also enables and improves the performance of virtualization services by allowing portions of their implementations to be hoisted into the guest, even uncooperatively. However, granting such privilege...

    Provided By Northwestern University

  • White Papers // Apr 2013

    VMM-based Emulation of Intel Hardware Transactional Memory

    The authors describe the design, implementation, and evaluation of emulated hardware transactional memory, specifically the Intel Haswell Restricted Transactional Memory (RTM) architectural extensions for x86/64, within a virtual machine monitor (VMM). Their system allows users to investigate RTM on hardware that does not provide it, debug their RTM-based transactional software,...

    Provided By Northwestern University

  • White Papers // Apr 2013

    Making JavaScript Better By Making It Even Slower

    On mobile devices, such as Smartphones and tablets, client-side JavaScript is a significant contributor to power consumption, and thus battery lifetime. The authors claim that this is partially due to JavaScript interpretation running faster than is necessary to maintain a satisfactory user experience, and they propose that JavaScript implementations include...

    Provided By Northwestern University

  • White Papers // Mar 2013

    The Public Safety Broadband Network: A Novel Architecture with Mobile Base Stations

    A nationwide interoperable public safety broadband network is being planned by the United States government. The network will be based on Long Term Evolution (LTE) standards and use recently designated spectrum in the 700 MHz band. The public safety network has different objectives and traffic patterns than commercial wireless networks....

    Provided By Northwestern University

  • White Papers // Mar 2013

    Evaluating Android Anti-Malware Against Transformation Attacks

    Mobile malware threats (e.g., on Android) have recently become a real concern. In this paper, the authors evaluate the state-of-the-art commercial mobile anti-malware products for Android and test how resistant they are against various common obfuscation techniques (even with known malware). Such an evaluation is important for not only measuring...

    Provided By Northwestern University

  • White Papers // Jan 2013

    AppsPlayground: Automatic Security Analysis of Smartphone Applications

    Today's smartphone application markets host an ever increasing number of applications. The sheer number of applications makes their review a daunting task. The authors propose AppsPlayground, a framework for automatically driving smartphone applications using their user interface characteristics, supporting complex user interactions, including the ability to create and supply login...

    Provided By Northwestern University

  • White Papers // Jan 2013

    Trying Broadband Characterization at Home

    In recent years the quantity and diversity of Internet-enabled consumer devices in the home have increased significantly. These trends complicate device usability and home resource management and have implications for crowdsourced approaches to broadband characterization. The UPnP protocol has emerged as an open standard for device and service discovery to...

    Provided By Northwestern University

  • White Papers // Jan 2013

    Spectrum Markets with Interference Complementarities

    Extensive spectrum markets have the potential to enable more efficient use of this limited resource. Such markets must account for particular properties of the underlying wireless medium. In this paper the authors focus on one such aspect: the role of interference created among different agents who may purchase the right...

    Provided By Northwestern University

  • White Papers // Nov 2012

    Multi-Cell Distributed Interference Cancellation for Co-Operative Pico-Cell Clusters

    Alternative wireless topologies, e.g., an underlay network of Pico-cells, are increasingly seen as being necessary to enhance capacity and coverage in next generation wireless systems. Such networks of closely-spaced base-sites have to contend with high interference issues, wherein interference mitigation via power control or interference co-ordination may not be sufficient....

    Provided By Northwestern University

  • White Papers // Oct 2012

    Enhancing Parallelism of Pairwise Statistical Significance Estimation for Local Sequence Alignment

    Pairwise Statistical Significance (PSS) has been found to be able to accurately identify related sequences (homology detection), which is a fundamental step in numerous applications relating to sequence analysis. Although more accurate than database statistical significance, it is both computationally intensive and data intensive to construct the empirical score distribution...

    Provided By Northwestern University

  • White Papers // Sep 2012

    Complexity of Allocation Problems in Spectrum Markets with Interference Complementarities

    Markets are often viewed as a key ingredient in facilitating more efficient dynamic spectrum access. In this paper the authors consider how such spectrum markets are influenced by a key property of the wireless medium: interference. Interference can result in "Complementarities" among the "Spectrum goods" being traded, which complicates the...

    Provided By Northwestern University

  • White Papers // Aug 2012

    Selective Behavior in Online Social Networks

    According to the classical communication theories, known as Gatekeeping and Selective Exposure, individuals tend to have selective behavior when they disseminate and receive information based on their psychological preferences. Selective behavior related to these two theories have been broadly studied separately. While, thanks to the advent of Online Social Networks...

    Provided By Northwestern University

  • White Papers // Jul 2012

    Dynamic Directories: A Mechanism for Reducing On-Chip Interconnect Power in Multicores

    On-chip interconnection networks consume a significant fraction of the chip's power, and the rapidly increasing core counts in future technologies is going to further aggravate their impact on the chip's overall power consumption. A large fraction of the traffic originates not from data messages exchanged between sharing cores, but from...

    Provided By Northwestern University

  • White Papers // Jun 2012

    HAPPE: Human and Application Driven Frequency Scaling for Processor Power Efficiency

    Conventional dynamic voltage and frequency scaling techniques use high CPU utilization as a predictor for user dissatisfaction, to which they react by increasing CPU frequency. In this paper, the authors demonstrate that for many interactive applications, perceived performance is highly-dependent upon the particular user and application, and is not linearly...

    Provided By Northwestern University

  • White Papers // May 2012

    Security of Electrostatic Field Persistent Routing: Attacks and Defense Mechanisms

    Electrostatic Field-based Routing (EFR) is a form of geographical multi-path routing where packets are routed along a collection of electrostatic field lines, defined by electrostatic charges associated with source and sink nodes. EFR provides an efficient and scalable solution to the workload balancing problem. However, it assumes that nodes behave...

    Provided By Northwestern University

  • White Papers // May 2012

    On the Path to Sustainable, Scalable, and Energy-efficient Data Analytics: Challenges, Promises, and Future Directions

    As scientific data is reaching exascale, scalable and energy efficient data analytics is quickly becoming a top notch priority. Yet, a sustainable solution to this problem is hampered by a number of technical challenges that get exacerbated with the emerging hardware and software technology trends. In this paper, the authors...

    Provided By Northwestern University

  • White Papers // Apr 2012

    Wireless MIMO Switching With MMSE Relaying

    A wireless relay which forms a one-to-one mapping from the inputs (uplinks) to the outputs (downlinks) is called a Multiple-Input-Multiple-Output (MIMO) switch. The MIMO switch carries out pre-code-and-forward, where all users send their signals in the uplink and then the MIMO switch pre-codes the received vector signal for broadcasting in...

    Provided By Northwestern University

  • White Papers // Apr 2012

    A Sparse Octree Gravitational N-Body Code That Runs Entirely on the GPU Processor

    The authors present the implementation and performance of a new gravitational N- body tree-code that is specifically designed for the Graphics Processing Unit (GPU). All parts of the tree-code algorithm are executed on the GPU. They present algorithms for parallel construction and traversing of sparse oc-trees. These algorithms are implemented...

    Provided By Northwestern University

  • White Papers // Mar 2012

    Virtual-Machine-Based Emulation of Future Generation High-Performance Computing Systems

    In this paper, the authors describe the design of a system to enable research, development, and testing of new software stacks and hardware features for future high-end computing systems. Motivating uses include both small-scale research and development on simulated individual nodes of proposed high-performance computing systems, and large scaling studies...

    Provided By Northwestern University

  • White Papers // Mar 2012

    Uplink Distributed Power and Receiver Optimization Across Multiple Cells

    Interference mitigation approaches in the presence of multiple receive antennas in the uplink of a multi-cell wireless communications system are studied in this paper. A formulation based on interference pricing is proposed, where it is shown that a single price per base-station can be computed and exchanged, in order to...

    Provided By Northwestern University

  • White Papers // Mar 2012

    Characterization of Vision-Aided Indoor Localization and Landmark Routing

    GPS is the premier method of localization and way-finding in outdoor environments. Indoor environments prevent GPS from functioning properly or at all. RF-based solutions have been proposed using varieties of radio triangulation and spectral fingerprinting. Such technically attractive methods have not seen widespread adoption in places where the demand is...

    Provided By Northwestern University

  • White Papers // Mar 2012

    VirtualKnotter: Online Virtual Machine Shuffling for Congestion Resolving in Virtualized Datacenter

    The authors measurements on production datacenter traffic together with recently-reported results suggest that datacenter networks suffer from long-lived congestion caused by core network oversubscription and unbalanced workload placement. In contrast to traditional traffic engineering approaches that optimize flow routing, in this paper, they explore the opportunity to address the continuous...

    Provided By Northwestern University

  • White Papers // Jan 2012

    Supporting Computational Data Model Representation with High-Performance I/O in Parallel NetCDF

    Parallel computational scientific applications have been described by their computation and communication patterns. From a storage and I/O perspective, these applications can also be grouped into separate data models based on the way data is organized and accessed during simulation, analysis, and visualization. Parallel netCDF is a popular library used...

    Provided By Northwestern University

  • White Papers // Jan 2012

    Improving the Average Response Time in Collective I/O

    In collective I/O, MPI processes exchange requests so that the rearranged requests can result in the shortest file system access time. Scheduling the exchange sequence determines the response time of participating processes. Existing implementations that simply follow the increasing order of file offsets do not necessary produce the best performance....

    Provided By Northwestern University

  • White Papers // Jan 2012

    Reliability Constrained Packet-Sizing for Linear Multi-Hop Wireless Networks

    The authors consider optimizing the packet-sizes and the reuse factor to minimize the delay required to send a message between two nodes in a linear multi-hop wireless network subject to a reliability constraint. Initially, assuming no re-use, they give a bound on the required delay. Next, in an infinite system...

    Provided By Northwestern University

  • White Papers // Sep 2011

    Sum-Capacity of a Class of K-user Gaussian Interference Channels within O(K) Bits

    Though the capacity of the 2-user Gaussian interference channel has long eluded information theorists, recent progress has been made by focusing on approximations with provable bounds. However, extensions to a general K-user network has proven to be non-obvious, in particular due to the role of interference alignment in these cases....

    Provided By Northwestern University

  • White Papers // Sep 2011

    Wireless MIMO Switching With Zero-Forcing Relaying

    A wireless relay with multiple antennas is called a Multiple-Input-Multiple-Output (MIMO) switch if it forms a one-to-one mapping from the inputs (uplinks) to the outputs (downlinks). This paper studies the case with N source stations and N destination stations (which may be the same set), so that the mapping is...

    Provided By Northwestern University

  • White Papers // Aug 2011

    Achieving Target MTTF by Duplicating Reliability-Critical Components in High Performance Computing Systems

    Mean Time To failure, MTTF, is a commonly accepted metric for reliability. In this paper, the authors present a novel approach to achieve the desired MTTF with minimum redundancy. They analyze the failure behavior of large scale systems using failure logs collected by Los Alamos National Laboratory. They analyze the...

    Provided By Northwestern University

  • White Papers // Jul 2011

    An Efficient FPGA Implementation of Principle Component Analysis Based Network Intrusion Detection System

    Modern Network Intrsuion Detection Systems (NIDSs) use anomaly detection to capture malicious attacks. Since such connections are described by large set of dimensions, processing these huge amounts of network data becomes extremely slow. To solve this time-efficiency problem, statistical methods like Principal Component Analysis (PCA) can be used to reduce...

    Provided By Northwestern University

  • White Papers // Jul 2011

    Evaluating Voltage Islands in CMPs under Process Variations

    Parameter variations are a major factor causing power-performance asymmetry in chip multiprocessors. In this paper, the authors analyze the effects of With-In-Die (WID) process variations on chip multicore processors and then apply a variable voltage island scheme to minimize power dissipation. Their idea is based on the observation that due...

    Provided By Northwestern University

  • White Papers // Jul 2011

    Exploring I/O Strategies for Parallel Sequence-Search Tools with S3aSim

    Parallel sequence-search tools are rising in popularity among computational biologists. With the rapid growth of sequence databases, database segmentation is the trend of the future for such search tools. While I/O currently is not a significant bottleneck for parallel sequence-search tools, future technologies including faster processors, customized computational hardware such...

    Provided By Northwestern University

  • White Papers // Jul 2011

    Challenges for Parallel I/O in Grid Computing

    With virtually limitless resources, GRID computing has the potential to solve large-scale scientific problems that eclipse even applications that run on the largest computing clusters today. The architecture of a computing GRID simply consists of a heterogeneous network infrastructure connecting heterogeneous machines presumed to be larger than most clusters of...

    Provided By Northwestern University

  • White Papers // Jul 2011

    VNET/P: Bridging the Cloud and High Performance Computing Through Fast Overlay Networking

    Overlay networking with a layer 2 abstraction provides a powerful model for virtualized wide-area distributed computing resources, including for High Performance Computing (HPC) on collections of Virtual Machines (VMs). With the emergence of cloud computing, it is now possible to allow VMs hosting tightly-coupled HPC applications to seamlessly migrate between...

    Provided By Northwestern University

  • White Papers // Jul 2011

    Medium Access Control for Wireless Networks With Peer-to-Peer State Exchange

    Distributed Medium Access Control (MAC) protocols are proposed for wireless networks assuming that one-hop peers can periodically exchange a small amount of state information. Each station maintains a state and makes state transitions and transmission decisions based on its state and recent state information collected from its one-hop peers. A...

    Provided By Northwestern University

  • White Papers // Jul 2011

    Delay Performance of CSMA in Networks With Bounded Degree Conflict Graphs

    The authors analyze packet delay in CSMA-based random access schemes in networks under the protocol interference model. Using a stochastic coupling argument they identify a subset of the throughput-region where queue lengths can be bounded uniformly for all network sizes. This conclusion provides a throughput-region of interest for delay sensitive...

    Provided By Northwestern University

  • White Papers // Jun 2011

    High Performance Data Mining Using R on Heterogeneous Platforms

    The exponential increase in the generation and collection of data has led users in a new era of data analysis and information extraction. Conventional systems based on general-purpose processors are unable to keep pace with the heavy computational requirements of data mining techniques. High performance coprocessors like GPUs and FPGAs...

    Provided By Northwestern University

  • White Papers // Jun 2011

    Learning and Leveraging the Relationship Between Architecture-Level Measurements and Individual User Satisfaction

    The ultimate goal of computer design is to satisfy the end-user. In particular computing domains, such as interactive applications, there exists a variation in user expectations and user satisfaction relative to the performance of existing computer systems. In this paper, the authors leverage this variation to develop more efficient architectures...

    Provided By Northwestern University

  • White Papers // Jun 2011

    Understanding Crowds' Migration on the Web

    Consider a network where nodes are websites and the weight of a link that connects two nodes corresponds to the average number of users that visits both of the two websites over longer timescales. Such user-driven Web network is not only invaluable for understanding how crowds' interests collectively spread on...

    Provided By Northwestern University

  • White Papers // May 2011

    Exploiting Peer-to-Peer State Exchange for Distributed Medium Access Control

    Distributed Medium Access Control (MAC) protocols are proposed for wireless networks assuming that one-hop peers can exchange a small amount of state information periodically. Each station maintains a state and makes state transitions and transmission decisions based on its state and recent state information collected from its one-hop peers. A...

    Provided By Northwestern University

  • White Papers // Jan 2012

    Improving the Average Response Time in Collective I/O

    In collective I/O, MPI processes exchange requests so that the rearranged requests can result in the shortest file system access time. Scheduling the exchange sequence determines the response time of participating processes. Existing implementations that simply follow the increasing order of file offsets do not necessary produce the best performance....

    Provided By Northwestern University

  • White Papers // Jun 2011

    High Performance Data Mining Using R on Heterogeneous Platforms

    The exponential increase in the generation and collection of data has led users in a new era of data analysis and information extraction. Conventional systems based on general-purpose processors are unable to keep pace with the heavy computational requirements of data mining techniques. High performance coprocessors like GPUs and FPGAs...

    Provided By Northwestern University

  • White Papers // Feb 2011

    Accelerating Data Mining Workloads: Current Approaches and Future Challenges in System Architecture Design

    Conventional systems based on general-purpose processors cannot keep pace with the exponential increase in the generation and collection of data. It is therefore important to explore alternative architectures that can provide the computational capabilities required to analyze ever-growing datasets. Programmable Graphics Processing Units (GPUs) offer computational capabilities that surpass even...

    Provided By Northwestern University

  • White Papers // Mar 2011

    Voice of the Customers: Mining Online Customer Reviews for Product Feature-Based Ranking

    Increasingly large numbers of customers are choosing online shopping because of its convenience, reliability, and cost. As the number of products being sold online increases, it is becoming increasingly difficult for customers to make purchasing decisions based on only pictures and short product descriptions. On the other hand, customer reviews,...

    Provided By Northwestern University

  • White Papers // Mar 2011

    pFANGS: Parallel High Speed Sequence Mapping for Next Generation 454-Roche Sequencing Reads

    Millions of DNA sequences (reads) are generated by Next Generation Sequencing machines every day. There is a need for high performance algorithms to map these sequences to the reference genome to identify single nucleotide polymorphisms or rare transcripts to fulfill the dream of personalized medicine. In this paper, the authors...

    Provided By Northwestern University

  • White Papers // Mar 2011

    Detecting/Preventing Information Leakage on the Memory Bus due to Malicious Hardware

    An increasing concern amongst designers and integrators of military and defense-related systems is the underlying security of the individual microprocessor components that make up these systems. Malicious circuitry can be inserted and hidden at several stages of the design process through the use of third-party Intellectual Property (IP), design tools,...

    Provided By Northwestern University

  • White Papers // Nov 2008

    Temperature-Aware Test Scheduling for Multiprocessor Systems-On-Chip

    Increasing power densities due to process scaling, combined with high switching activity and poor cooling environments during testing, have the potential to result in high Integrated Circuit (IC) temperatures. This has the potential to damage ICs and cause good ICs to be discarded due to temperature-induced timing faults. The authors...

    Provided By Northwestern University

  • White Papers // Jun 2011

    Learning and Leveraging the Relationship Between Architecture-Level Measurements and Individual User Satisfaction

    The ultimate goal of computer design is to satisfy the end-user. In particular computing domains, such as interactive applications, there exists a variation in user expectations and user satisfaction relative to the performance of existing computer systems. In this paper, the authors leverage this variation to develop more efficient architectures...

    Provided By Northwestern University

  • White Papers // Jul 2011

    An Efficient FPGA Implementation of Principle Component Analysis Based Network Intrusion Detection System

    Modern Network Intrsuion Detection Systems (NIDSs) use anomaly detection to capture malicious attacks. Since such connections are described by large set of dimensions, processing these huge amounts of network data becomes extremely slow. To solve this time-efficiency problem, statistical methods like Principal Component Analysis (PCA) can be used to reduce...

    Provided By Northwestern University

  • White Papers // Jul 2011

    Evaluating Voltage Islands in CMPs under Process Variations

    Parameter variations are a major factor causing power-performance asymmetry in chip multiprocessors. In this paper, the authors analyze the effects of With-In-Die (WID) process variations on chip multicore processors and then apply a variable voltage island scheme to minimize power dissipation. Their idea is based on the observation that due...

    Provided By Northwestern University

  • White Papers // Jul 2011

    Exploring I/O Strategies for Parallel Sequence-Search Tools with S3aSim

    Parallel sequence-search tools are rising in popularity among computational biologists. With the rapid growth of sequence databases, database segmentation is the trend of the future for such search tools. While I/O currently is not a significant bottleneck for parallel sequence-search tools, future technologies including faster processors, customized computational hardware such...

    Provided By Northwestern University

  • White Papers // Jul 2011

    Challenges for Parallel I/O in Grid Computing

    With virtually limitless resources, GRID computing has the potential to solve large-scale scientific problems that eclipse even applications that run on the largest computing clusters today. The architecture of a computing GRID simply consists of a heterogeneous network infrastructure connecting heterogeneous machines presumed to be larger than most clusters of...

    Provided By Northwestern University

  • White Papers // Aug 2010

    Asymptotic Analysis of Downlink OFDMA Capacity

    The authors consider asymptotic performance of a downlink OFDMA system as the number of users and sub-channels increase. Specifically, they study the asymptotic growth in the weighted sum capacity, where each user is assigned a weight to reflect its quality of service. They begin by considering a limited feedback scheme,...

    Provided By Northwestern University

  • White Papers // Sep 2008

    Distributed Interference Pricing with MISO Channels

    The authors study a distributed algorithm for adapting transmit beamforming vectors in a multi-antenna peer-to-peer wireless network. The algorithm attempts to maximize a sum of per-user utility functions, where each user's utility is a function of his transmission rate, or equivalently the received Signal-to-Interference plus Noise Ratio (SINR). This is...

    Provided By Northwestern University

  • White Papers // Nov 2009

    Incentives and Resource Sharing in Spectrum Commons

    It has been suggested that light regulation in the form of etiquette protocols, device design and bargaining amongst users will suffice to mitigate a tragedy of the commons in unlicensed spectrum. In this paper, the authors propose a game theoretic model to examine this claim. In this game, each user...

    Provided By Northwestern University

  • White Papers // Nov 2009

    Spectrum Markets for Wireless Services

    It has been widely recognized that the current under-utilization of spectrum across many bands could be alleviated through the application of spectrum markets. So far, discussions of market mechanisms for spectrum allocations have focused primarily on secondary markets, which are managed by licensees. Here the authors explore the consequences of...

    Provided By Northwestern University

  • White Papers // Apr 2009

    Information Theory Meets Game Theory on The Interference Channel

    The authors consider a game theoretic model for two users communicating over an interference channel, in which each user can autonomously select its encoding and decoding strategy with the objective of maximizing its own rate. They give an information theoretic formulation for this game, which enables users to define a...

    Provided By Northwestern University

  • White Papers // Nov 2009

    Distributed Interference Pricing for the MIMO Interference Channel

    The authors study distributed algorithms for updating transmit precoding matrices for a two-user Multi-Input/Multi-Output (MIMO) interference channel. Their objective is to maximize the sum rate with linear Minimum Mean Squared Error (MMSE) receivers, treating the interference as additive Gaussian noise. An iterative approach is considered in which given a set...

    Provided By Northwestern University

  • White Papers // Apr 2009

    Monotonic Convergence of Distributed Interference Pricing in Wireless Networks

    The authors study distributed algorithms for allocating powers and/or adjusting beamforming vectors in a peer-to-peer wireless network which may have Multiple-Input-Single-Output (MISO) links. The objective is to maximize the total utility summed over all users, where each user's utility is a function of the received Signal-to-Interference-plus-Noise Ratio (SINR). Each user...

    Provided By Northwestern University

  • White Papers // Aug 2009

    Scalable Video Coding and Packet Scheduling for Multiuser Video Transmission Over Wireless Networks

    Wireless video transmission is prone to potentially low data rates and unpredictable degradations due to time-varying channel conditions. Such degradations are difficult to overcome using conventional video coding techniques. Scalable video coding offers a flexible bitstream that can be dynamically adapted to t the prevailing channel conditions. Advances in scalable...

    Provided By Northwestern University

  • White Papers // Jan 2013

    Trying Broadband Characterization at Home

    In recent years the quantity and diversity of Internet-enabled consumer devices in the home have increased significantly. These trends complicate device usability and home resource management and have implications for crowdsourced approaches to broadband characterization. The UPnP protocol has emerged as an open standard for device and service discovery to...

    Provided By Northwestern University

  • White Papers // Aug 2012

    Selective Behavior in Online Social Networks

    According to the classical communication theories, known as Gatekeeping and Selective Exposure, individuals tend to have selective behavior when they disseminate and receive information based on their psychological preferences. Selective behavior related to these two theories have been broadly studied separately. While, thanks to the advent of Online Social Networks...

    Provided By Northwestern University

  • White Papers // Feb 2011

    Towards Street-Level Client-Independent IP Geolocation

    A highly accurate client-independent geolocation service stands to be an important goal for the Internet. Despite an extensive research effort and significant advances in this area, this goal has not yet been met. Motivated by the fact that the best results to date are achieved by utilizing additional 'Hints' beyond...

    Provided By Northwestern University

  • White Papers // Aug 2009

    Googling the Internet: Profiling Internet Endpoints via the World Wide Web

    Understanding Internet access trends at a global scale, i.e., how people use the Internet, is a challenging problem that is typically addressed by analyzing network traces. However, obtaining such traces presents its own set of challenges owing to either privacy concerns or to other operational difficulties. The key hypothesis of...

    Provided By Northwestern University

  • White Papers // Mar 2010

    Strange Bedfellows: Community Identification in BitTorrent

    While P2P systems benefit from large numbers of interconnected nodes, each of these connections provides an opportunity for eavesdropping. Using only the connection patterns gathered from 10,000 BitTorrent (BT) users during a one-month period, the authors determine whether randomized connection patterns give rise to communities of users. Even though connections...

    Provided By Northwestern University

  • White Papers // Apr 2010

    Network Positioning From the Edge: An Empirical Study of the Effectiveness of Network Positioning in P2P Systems

    Network positioning systems provide an important service to large-scale P2P systems, potentially enabling clients to achieve higher performance, reduce cross-ISP traffic and improve the robustness of the system to failures. Because traces representative of this environment are generally unavailable, and there is no platform suited for experimentation at the appropriate...

    Provided By Northwestern University

  • White Papers // May 2009

    Distributed or Centralized Traffic Advisory Systems-The Application's Take

    The authors consider the problem of data dissemination in vehicular networks. Their main goal is to compare the application-level performance of fully distributed and centralized data dissemination approaches in the context of traffic advisory systems. Vehicular networks are emerging as a new distributed system environment with myriad promising applications. Wirelessly-connected,...

    Provided By Northwestern University

  • White Papers // Mar 2009

    Down the Block and Around the Corner - The Impact of Radio Propagation on Inter-Vehicle Wireless Communication

    Vehicular networks are emerging as a new distributed system environment with myriad possible applications. Most studies on vehicular networks are carried out via simulation, given the logistical and economical problems with large-scale deployments. This paper investigates the impact of realistic radio propagation settings on the evaluation of VANET-based systems. Using...

    Provided By Northwestern University

  • White Papers // Apr 2009

    On the Effectiveness of Measurement Reuse for Performance-Based Detouring

    For both technological and economic reasons, the default path between two end systems in the wide-area Internet can be suboptimal. This observation has motivated a number of systems that attempt to improve reliability and performance by routing over one or more hops in an overlay. Most of the proposed solutions,...

    Provided By Northwestern University

  • White Papers // Jan 2013

    AppsPlayground: Automatic Security Analysis of Smartphone Applications

    Today's smartphone application markets host an ever increasing number of applications. The sheer number of applications makes their review a daunting task. The authors propose AppsPlayground, a framework for automatically driving smartphone applications using their user interface characteristics, supporting complex user interactions, including the ability to create and supply login...

    Provided By Northwestern University

  • White Papers // Mar 2012

    VirtualKnotter: Online Virtual Machine Shuffling for Congestion Resolving in Virtualized Datacenter

    The authors measurements on production datacenter traffic together with recently-reported results suggest that datacenter networks suffer from long-lived congestion caused by core network oversubscription and unbalanced workload placement. In contrast to traditional traffic engineering approaches that optimize flow routing, in this paper, they explore the opportunity to address the continuous...

    Provided By Northwestern University

  • White Papers // Jul 2012

    Dynamic Directories: A Mechanism for Reducing On-Chip Interconnect Power in Multicores

    On-chip interconnection networks consume a significant fraction of the chip's power, and the rapidly increasing core counts in future technologies is going to further aggravate their impact on the chip's overall power consumption. A large fraction of the traffic originates not from data messages exchanged between sharing cores, but from...

    Provided By Northwestern University

  • White Papers // Jan 2012

    Supporting Computational Data Model Representation with High-Performance I/O in Parallel NetCDF

    Parallel computational scientific applications have been described by their computation and communication patterns. From a storage and I/O perspective, these applications can also be grouped into separate data models based on the way data is organized and accessed during simulation, analysis, and visualization. Parallel netCDF is a popular library used...

    Provided By Northwestern University

  • White Papers // Oct 2010

    Virtual Full-Duplex Wireless Communication Via Rapid On-Off-Division Duplex

    This paper introduces a novel paradigm for designing the physical and Medium Access Control (MAC) layers of mobile ad hoc or peer-to-peer networks formed by half-duplex radios. A node equipped with such a radio cannot simultaneously transmit and receive useful signals at the same frequency. Unlike in conventional designs, where...

    Provided By Northwestern University

  • White Papers // Dec 2010

    The Dynamics Of Innovation

    The authors analyze social learning and innovation in an overlapping generations model in which available technologies have correlated payoffs. Each generation experiments within a set of policies whose payoffs are initially unknown and drawn from the path of a Brownian motion with drift. Marginal innovation consists in choosing a technology...

    Provided By Northwestern University

  • White Papers // Aug 2010

    Sequential Rationality in Cryptographic Protocols

    Much of the literature on rational cryptography focuses on analyzing the strategic properties of cryptographic protocols. However, due to the presence of computationally bounded players and the asymptotic nature of cryptographic security, a definition of sequential rationality for this setting has thus far eluded researchers. The authors propose a new...

    Provided By Northwestern University

  • White Papers // Apr 2010

    Synergy Between Automatic Content Generation and Social Media

    Finding out about a topic online involves visiting multiple news sites, encyclopedia entries, video repositories and other resources while discarding irrelevant information. MakeMy-Page aims to speed the search process by combining automatic aggregation of information with social media to build persistent web pages with images, videos and links to important...

    Provided By Northwestern University

  • White Papers // Dec 2010

    WebShield: Enabling Various Web Defense Techniques Without Client Side Modifications

    Today, web attacks are increasing in frequency, severity and sophistication. Existing solutions are either host based which suffer deployment problems or middlebox approaches that can only accommodate certain security protection mechanisms with limited protection. In this paper, the authors propose four design principles for general middlebox frameworks of web protection,...

    Provided By Northwestern University

  • White Papers // Jan 2011

    Hamsa: Fast Signature Generation for Zero-Day Polymorphic Worms With Provable Attack Resilience

    Zero-day polymorphic worms pose a serious threat to the security of Internet infrastructures. Given their rapid propagation, it is crucial to detect them at edge networks and automatically generate signatures in the early stages of infection. Most existing approaches for automatic signature generation need host information and are thus not...

    Provided By Northwestern University

  • White Papers // May 2009

    Sonar-Based Measurement of User Attention

    The authors describe a technique to determine presence and attention levels of computer users. This technique relies on sonar using hardware that already exists on commodity laptop computers and other electronic devices. It leverages the fact that human bodies have a different effect on sound waves than air and other...

    Provided By Northwestern University