University of British Columbia

Displaying 1-40 of 98 results

  • White Papers // Oct 2012

    Profit Maximization Over Social Networks

    Influence maximization is the problem of finding a set of influential users in a social network such that the expected spread of influence under a certain propagation model is maximized. Much of the previous work has neglected the important distinction between social influence and actual product adoption. However, as recognized...

    Provided By University of British Columbia

  • White Papers // Dec 2011

    Evolutionary Search-Based Test Generation for Software Product Line Feature Models

    Product line-based software engineering is a paradigm that models the commonalities and variabilities of different applications of a given domain of interest within a unique framework and enhances rapid and low cost development of new applications based on reuse engineering principles. Despite the numerous advantages of software product lines, it...

    Provided By University of British Columbia

  • White Papers // Nov 2011

    Bounding Interference in Wireless Ad Hoc Networks With Nodes in Random Position

    The interference at a wireless node s can be modelled by the number of wireless nodes whose trans-mission ranges cover s. Given a set of positions for wireless nodes, the interference minimization problem is to assign a transmission radius (equivalently, a power level) to each node such that the resulting...

    Provided By University of British Columbia

  • White Papers // Sep 2011

    Admission Control and Resource Optimization for Multiple-User OFDMA Cognitive Radio Systems

    In Cognitive Radio (CR) systems, the fluctuating nature of the available frequency resource due to Primary Users (PUs) activity necessitates the introduction of admission and eviction measures at the CR system if a guaranteed Quality of Service (QoS) is required by Real Time (RT) Secondary Users (SUs). This problem has...

    Provided By University of British Columbia

  • White Papers // Sep 2011

    Neighborhood-Knowledge Based Routing in PLC

    One of the challenges of employing Power Line Communication (PLC) in power distribution grids is routing messages using multihop transmission or, in other words, by relaying information through decode and forward packets. In this contribution, the authors show a possible compromise between energy consumption and delivery delay that are performance...

    Provided By University of British Columbia

  • White Papers // Sep 2011

    Inferring Power Line Network Topology Using Frequency Domain Reflectometry

    Power Line Communications (PLC) is an attractive means of data communication for a variety of scenarios and applications, including in-home multimedia and utility applications, the latter of which have gained renewed attention under the label of Smart Grid. The analysis and design of PLC systems should rely on sufficiently accurate...

    Provided By University of British Columbia

  • White Papers // Jul 2011

    A Stackelberg Game for Cooperative Transmission and Random Access in Cognitive Radio Networks

    In cognitive radio networks, the Secondary Users (SUs) can be selected as the cooperative relays to assist the transmission of the Primary User (PU). In order to increase the utility, the PU needs to consider whether it is beneficial to use cooperative transmission and which SU should be chosen as...

    Provided By University of British Columbia

  • White Papers // Jul 2011

    Optimal Real-Time Pricing Algorithm Based on Utility Maximization for Smart Grid

    In this paper, the authors consider a smart power infrastructure, where several subscribers share a common energy source. Each subscriber is equipped with an Energy Consumption Controller (ECC) unit as part of its smart meter. Each smart meter is connected to not only the power grid but also a communication...

    Provided By University of British Columbia

  • White Papers // Jul 2011

    Design of Pre-Rake DS-UWB Downlink With Pre-Equalization

    The authors consider the design of Ultra-WideBand (UWB) systems that enable high data rate communications for short-range wireless applications. In particular, they consider the downlink of a Direct Sequence UWB (DS-UWB) system in which the base station is equipped with multiple antennas and employs pre-rake combining, while each user employs...

    Provided By University of British Columbia

  • White Papers // Jul 2011

    A Coalition Formation Game for Energy-Efficient Cooperative Spectrum Sensing in Cognitive Radio Networks With Multiple Channels

    Spectrum sensing is one of the key technologies to realize spectrum reuse and increase the spectrum efficiency in Cognitive Radio Networks (CRNs). In this paper, the authors study energy-efficient cooperative multi-channel spectrum sensing in CRNs. They first propose a Cooperative Spectrum Sensing and Accessing (CSSA) scheme for all the Secondary...

    Provided By University of British Columbia

  • White Papers // Jul 2011

    Downlink Scheduling With Transmission Strategy Selection for Two-Cell MIMO Networks

    Multiple-Input Multiple-Output (MIMO) processing is a promising technique to achieve high speed data service in next generation cellular networks. However, the performance of multi-cell MIMO networks is limited by the cell-edge users who experience significant inter-cell interference. In this paper, the authors propose to use interference alignment to mitigate interference...

    Provided By University of British Columbia

  • White Papers // Jul 2011

    Context-Aware Mobility Management in Heterogeneous Network Environments

    Context-aware mobility management can provide major enhancements for future mobile communication systems. Not only it considers device mobility, but session mobility is also considered. Context-awareness is a key ingredient in any ubiquitous and pervasive system and provides intelligence to the system, allowing computing devices make appropriate and timely decisions on...

    Provided By University of British Columbia

  • White Papers // Jun 2011

    Profiling-as-a-Service: Adaptive Scalable Resource Profiling for the Cloud in the Cloud

    Run-time profiling of Web-based applications and services is an effective method to aid in the provisioning of required resources, for monitoring server-level objectives, and for detecting implementation defects. Unfortunately, it is difficult to obtain accurate profile data on live client workloads due to the high overhead of instrumentation. This paper...

    Provided By University of British Columbia

  • White Papers // Jun 2011

    Strategic Investments, Technological Uncertainty, And Expected Return Externalities

    The authors study the effect of competition in technological innovation on asset prices. Using a model of an innovation race in which firms face both technological and market-wide uncertainty when they exercise innovation options, they show that a firm's investment in innovation imposes an expected return "Externality" on its rivals....

    Provided By University of British Columbia

  • White Papers // May 2011

    Calibration And Filtering For Multi Factor Commodity Models With Seasonality: Incorporating Panel Data From Futures Contracts

    The authors examine a general multi-factor model for commodity spot prices and futures valuation. They extend the multi-factor long-short model in and in two important aspects: firstly, they allow for both the long and short term dynamic factors to be mean reverting incorporating stochastic volatility factors and secondly, they develop...

    Provided By University of British Columbia

  • White Papers // May 2011

    Exposing File System Mappings With MapFS

    The conventional model of a file as a contiguous array of bytes hides information about the physical location of data from users. While this simplifying abstraction can be useful in some cases, it can also lead to suboptimal performance and unnecessary overhead. A growing number of applications - even those...

    Provided By University of British Columbia

  • White Papers // Apr 2011

    Schedule Data, Not Code

    In this paper, the authors argue that the scheduler, as the intermediary between hardware and software, needs to be fully data-aware. The old paradigm of envisioning tasks as amorphous blobs of 'Work' to be assigned to processors is incomplete and needs be expanded. Some techniques and projects have emerged that...

    Provided By University of British Columbia

  • White Papers // Apr 2011

    On Cooperative Coding for Narrowband PLC Networks

    Low-Frequency NarrowBand (LF NB) Power Line Communications (PLC) is an old data-communication concept that has received renewed interest in industry, standardization, and academia for its potential to become an important element of the communication infrastructure supporting Smart Grid applications. In this paper, dedicated to Prof. Johannes Huber on the occasion...

    Provided By University of British Columbia

  • White Papers // Apr 2011

    Second Order Cone Programming for Sensor Network Localization With Anchor Position Uncertainty

    The authors consider the problem of node localization in sensor networks, and they focus on networks in which the ranging measurements are subject to errors and anchor positions are subject to uncertainty. They consider a statistical model for the uncertainty in the anchor positions and formulate the robust localization problem...

    Provided By University of British Columbia

  • White Papers // Mar 2011

    VMFlock: Virtual Machine Co-Migration for the Cloud

    This paper presents VMFlockMS, a migration service optimized for cross-datacenter transfer and instantiation of groups of Virtual Machine (VM) images that comprise an application-level solution (e.g., a three-tier web application). The authors dub these groups of related VM images VMFlocks. VMFlockMS employs two main techniques: first, data deduplication within the...

    Provided By University of British Columbia

  • White Papers // Feb 2011

    Optimal Data Transmission and Channel Code Rate Allocation in Multi-Path Wireless Networks

    Wireless links are often unreliable and prone to transmission error due to varying channel conditions. These can degrade the performance in wireless networks, particularly for applications with tight quality-of-service requirements. A common remedy is to use channel coding where the transmitter node adds redundant bits to the transmitted packets in...

    Provided By University of British Columbia

  • White Papers // Feb 2011

    Dynamic Optimal Random Access for Vehicle-to-Roadside Communications

    In a drive-thru scenario where vehicles drive by a roadside Access Point (AP) to obtain temporary Internet access, it is important to design efficient resource allocation schemes to fully utilize the limited communication opportunities. In this paper, the authors study the random access problem in drive-thru communications in a dynamic...

    Provided By University of British Columbia

  • White Papers // Feb 2011

    Dynamic Decode-and-Forward Relaying Using Raptor Codes

    Dynamic Decode-and-Forward (DDF) is a version of decode-and-forward relaying in which the duration of the listening phase at relays is not fixed. In this paper, the authors investigate half-duplex DDF relaying based on rateless codes. The use of rateless codes allows relays to autonomously switch from listening to the source...

    Provided By University of British Columbia

  • White Papers // Feb 2011

    Economics Of Cross-border Travel

    National borders have been shown to segment markets and generate price differences. The resulting arbitrage opportunities vary over time with the exchange rate and cross-sectionally with distance to the border. The authors estimate a structural model of the border crossing decision using a new dataset containing the residence of each...

    Provided By University of British Columbia

  • White Papers // Jan 2011

    Bursty Impulse Noise Detection by Compressed Sensing

    Impulse Noise (IN) is one of the major impairments for data transmission over power lines. For Power Line Communications (PLC) systems with bandwidths in the high kHz to MHz range, IN occurs in bursts. As long as those bursts are sufficiently short compared to a signal-processing (e.g. coding) frame, there...

    Provided By University of British Columbia

  • White Papers // Jan 2011

    Robust Cyclic Space-Frequency Filtering for BICM-OFDM With Outdated CSIT

    In this paper, the authors introduce robust Cyclic Space - Frequency (CSF) filtering for systems combining Bit - Interleaved Coded Modulation (BICM) and Orthogonal Frequency Division Multiplexing (OFDM). The proposed robust CSF filtering scheme exploits outdated Channel State Information at the Transmitter (CSIT) and takes into account the reliability of...

    Provided By University of British Columbia

  • White Papers // Dec 2010

    Capo: Recapitulating Storage for Virtual Desktops

    Fast and reliable data storage is something that organizations are prepared to pay a premium for, both in the capital costs of enterprise storage hardware and the operational costs of ensuring that important data is written to it. Interestingly, the deployment of virtualization has inverted the historical imperative that systems...

    Provided By University of British Columbia

  • White Papers // Dec 2010

    Evaluation of Wireless Body Area Sensor Placement for Mobility Support in Healthcare Monitoring Systems

    The authors present a 2-tier wireless system for healthcare monitoring of convalescing patients in non-critical condition. A network of sensors adhered to the patient's body used for vital signs collection, and a portable coordinator device forms one tier, whereas a point-to-point link between the coordinator and a fixed access point...

    Provided By University of British Columbia

  • White Papers // Oct 2010

    RLAB: A Reinforcement Learning-Based Adaptive Broadcasting for Vehicular Ad-Hoc Networks

    Effective context-aware broadcasting of information to the Areas of Interest (AoI) is a challenging problem in vehicular ad-hoc networks. It is usually assumed that the information about these AoI are a priori known, either by a centralized source of information or by the entire set of vehicles. In this paper,...

    Provided By University of British Columbia

  • White Papers // Sep 2010

    Outage Rate and Outage Duration of Decode-and-Forward Cooperative Diversity Systems

    A complete evaluation of the benefits of cooperative diversity schemes should not only include the outage and error rate performance but also the second-order statistics of the achievable information-theoretic capacity. In a non-ergodic fading channel, the system is said to be in outage when the destination cannot decode the fixed-rate...

    Provided By University of British Columbia

  • White Papers // Sep 2010

    Bit-Interleaved Coded Modulation With Mismatched Decoding Metrics

    Bit-Interleaved Coded Modulation (BICM) has become the de facto coding standard for communication systems. Recently, BICM has been cast as a mismatched decoding scheme due to the assumption of independent bit metrics. In addition to this inherent mismatch, practical demodulators may produce mismatched decoding metrics because of implementation constraints, such...

    Provided By University of British Columbia

  • White Papers // Aug 2010

    Content Caching and Replication Schemes for Peer-to-Peer File Sharing in Wireless Mesh Networks

    Wireless Mesh Networks (WMNs) have emerged as an important technology in building next generation fixed wireless broadband networks that provide low cost Internet access for fixed and mobile users. An orthogonal evolution in computer networking has been the rise of Peer-to-Peer (P2P) applications such as P2P file sharing. It is...

    Provided By University of British Columbia

  • White Papers // Aug 2010

    Pyramidal Ownership And The Creation Of New Firms

    The authors study the role of pyramidal ownership in the creation of new firms using a comprehensive panel of manufacturing firms in Europe. Pyramidal ownership structures are used to supply inside funds to new firms that are unable to raise enough external financing, namely, those with large investment requirements and...

    Provided By University of British Columbia

  • White Papers // Aug 2010

    DoDOM: Leveraging DOM Invariants for Web 2.0 Application Robustness Testing

    Web 2.0 applications are increasing in popularity. However, they are also prone to errors because of their dynamic nature. This paper presents DoDOM, an automated system for testing the robustness of Web 2.0 applications based on their Document Object Models (DOMs). DoDOM repeatedly executes the application under a trace of...

    Provided By University of British Columbia

  • White Papers // Aug 2010

    Technological Progress, Industry Rivalry, And Stock Returns

    In this paper the authors investigate the link between competition in technological innovation and asset prices. They develop a model of an innovation race in which firms are subject to technological as well as market-wide uncertainty and optimally exercise their options to innovate. The model predicts that the race leader...

    Provided By University of British Columbia

  • White Papers // Jun 2010

    Fast and Cautious Evolution of Cloud Storage

    When changing a storage system, the stakes are high. Any modification can undermine stability, causing temporary downtime, a permanent loss of data, and still worse - a loss of user confidence. This results in a cautious conservatism among storage developers. On one hand, the risks do justify taking great care...

    Provided By University of British Columbia

  • White Papers // May 2010

    Achieving Fairness in Distributed Cognitive Radio Networks Using a Timer Mechanism

    The authors consider the issue of fairness in scheduler design for distributed Cognitive Radio Networks (CRN). They first distinguish between intra- and inter-class fairness as a result of hierarchical resource access right in a secondary spectrum allocation regime. Further, they develop a timer mechanism to achieve round-robin, max-min and proportional...

    Provided By University of British Columbia

  • White Papers // Apr 2010

    Evaluating Two Window Manipulation Techniques on a Large Screen Display

    Large screen displays are a common feature of modern meeting rooms, conference halls, and classrooms. The large size and often high resolution of these displays make them inherently suitable for collaborative work, but these attributes cause traditional windowing systems to become difficult to use because the interaction handles become smaller...

    Provided By University of British Columbia

  • White Papers // Apr 2010

    What Determines European Real Exchange Rates?

    The authors study a newly constructed panel data set of relative prices of a large number of consumer goods among 31 European countries. They find that there is a substantial and non-diminishing deviation from PPP at all levels of aggregation, even among euro zone members. However, real exchange rates are...

    Provided By University of British Columbia

  • White Papers // Feb 2010

    A Linear Algebraic Approach for Loss Tomography in Mesh Topologies Using Network Coding

    Loss tomography aims to infer link loss rates using end-to-end measurements. The authors investigate active loss tomography on mesh topologies. When network coding is applied, based on the content of the received probe packet, a receiver should distinguish which paths have successfully transmitted a probe and which paths have not....

    Provided By University of British Columbia

  • White Papers // Aug 2009

    Reliability-Based Rate Allocation in Wireless Inter-Session Network Coding Systems

    Network coding has recently received increasing attention to improve performance and increase capacity in both wired and wireless communication networks. In this paper, the authors focus on inter-session network coding, where multiple unicast sessions jointly participate in network coding. Wireless links are often unreliable because of varying channel conditions. They...

    Provided By University of British Columbia

  • White Papers // Feb 2011

    Optimal Data Transmission and Channel Code Rate Allocation in Multi-Path Wireless Networks

    Wireless links are often unreliable and prone to transmission error due to varying channel conditions. These can degrade the performance in wireless networks, particularly for applications with tight quality-of-service requirements. A common remedy is to use channel coding where the transmitter node adds redundant bits to the transmitted packets in...

    Provided By University of British Columbia

  • White Papers // Feb 2011

    Dynamic Optimal Random Access for Vehicle-to-Roadside Communications

    In a drive-thru scenario where vehicles drive by a roadside Access Point (AP) to obtain temporary Internet access, it is important to design efficient resource allocation schemes to fully utilize the limited communication opportunities. In this paper, the authors study the random access problem in drive-thru communications in a dynamic...

    Provided By University of British Columbia

  • White Papers // Feb 2009

    Random Access Protocols for WLANs Based on Mechanism Design

    In Wireless Local Area Networks (WLANs), Quality of Service (QoS) can be provided by mapping applications with different requirements (e.g., delay and throughput) into one of the available Access Categories (ACs), as is done in the IEEE 802.11e standard. With the increasing programmability of network adapters, a malicious user can...

    Provided By University of British Columbia

  • White Papers // Feb 2010

    A Linear Algebraic Approach for Loss Tomography in Mesh Topologies Using Network Coding

    Loss tomography aims to infer link loss rates using end-to-end measurements. The authors investigate active loss tomography on mesh topologies. When network coding is applied, based on the content of the received probe packet, a receiver should distinguish which paths have successfully transmitted a probe and which paths have not....

    Provided By University of British Columbia

  • White Papers // Jul 2011

    A Coalition Formation Game for Energy-Efficient Cooperative Spectrum Sensing in Cognitive Radio Networks With Multiple Channels

    Spectrum sensing is one of the key technologies to realize spectrum reuse and increase the spectrum efficiency in Cognitive Radio Networks (CRNs). In this paper, the authors study energy-efficient cooperative multi-channel spectrum sensing in CRNs. They first propose a Cooperative Spectrum Sensing and Accessing (CSSA) scheme for all the Secondary...

    Provided By University of British Columbia

  • White Papers // Jul 2011

    A Stackelberg Game for Cooperative Transmission and Random Access in Cognitive Radio Networks

    In cognitive radio networks, the Secondary Users (SUs) can be selected as the cooperative relays to assist the transmission of the Primary User (PU). In order to increase the utility, the PU needs to consider whether it is beneficial to use cooperative transmission and which SU should be chosen as...

    Provided By University of British Columbia

  • White Papers // Feb 2010

    Optimal MISO UWB Pre-Equalizer Design With Spectral Mask Constraints

    In this paper, the authors propose a novel optimizationbased Pre-Equalization Filter (PEF) design for Multiple-Input Single-Output (MISO) Direct-Sequence Ultra-WideBand (DS-UWB) systems with pre-Rake combining. The key feature in their design is that they explicitly take into account spectral mask constraints which are usually imposed by telecommunications regulation and standardization bodies....

    Provided By University of British Columbia

  • White Papers // Oct 2008

    Simple, Optimal, and Robust Random Access

    In this paper, the authors propose two distributed contention-based Medium Access Control (MAC) algorithms to solve a Network Utility Maximization (NUM) problem in wireless ad hoc networks. Most of the previous NUM-based random access algorithms have one or more of the following performance bottlenecks: extensive signaling among nodes, synchronous updates...

    Provided By University of British Columbia

  • White Papers // Feb 2009

    A Game-Theoretic Analysis of Inter-Session Network Coding

    A common assumption in the network coding literature is that the users are cooperative and will not pursue their own interests. However, this assumption can be violated in practice. In this paper, the authors analyze inter-session network coding in a wired network, assuming that the users are selfish and act...

    Provided By University of British Columbia

  • White Papers // Dec 2009

    Bargaining and Price-of-Anarchy in Repeated Inter-Session Network Coding Games

    Most of the previous work on network coding has assumed that the users are not selfish and always follow the designed coding schemes. However, recent results have shown that selfish users do not have the incentive to participate in inter-session network coding in a static non-cooperative game setting. As a...

    Provided By University of British Columbia

  • White Papers // Feb 2010

    Pre-Equalization for DS-UWB Systems With Spectral Mask Constraints

    In this paper, the authors propose a novel optimization-based Pre-Equalization Filter (PEF) design for Direct-Sequence Ultra-WideBand (DS-UWB) systems with pre-Rake combining. The key feature in their design is that they explicitly take into account the spectral mask constraints that are usually imposed by the telecommunication regulation bodies. This avoids the...

    Provided By University of British Columbia

  • White Papers // Aug 2009

    Randomized Multi-Channel Interrogation Algorithm for Large-Scale RFID Systems

    A Radio Frequency IDentification (RFID) system consists of a set of readers and several objects, equipped with small computer chips, called tags. In a dense RFID system, where several readers are placed together to improve the read rate and correctness, readers and tags can frequently experience packet collision. A common...

    Provided By University of British Columbia

  • White Papers // Dec 2009

    Optimal SINR-Based Random Access

    Random access protocols, such as Aloha, are commonly modeled in wireless ad-hoc networks by using the protocol model. However, it is well-known that the protocol model is not accurate and particularly it cannot account for aggregate interference from multiple interference sources. In this paper, the authors use the more accurate...

    Provided By University of British Columbia

  • White Papers // Oct 2009

    Optimal and Autonomous Incentive-Based Energy Consumption Scheduling Algorithm for Smart Grid

    In this paper, the authors consider deployment of Energy Consumption Scheduling (ECS) devices in smart meters for autonomous demand side management within a neighborhood, where several buildings share an energy source. The ECS devices are assumed to be built inside smart meters and to be connected to not only the...

    Provided By University of British Columbia

  • White Papers // Jul 2011

    Downlink Scheduling With Transmission Strategy Selection for Two-Cell MIMO Networks

    Multiple-Input Multiple-Output (MIMO) processing is a promising technique to achieve high speed data service in next generation cellular networks. However, the performance of multi-cell MIMO networks is limited by the cell-edge users who experience significant inter-cell interference. In this paper, the authors propose to use interference alignment to mitigate interference...

    Provided By University of British Columbia

  • White Papers // Jul 2011

    Optimal Real-Time Pricing Algorithm Based on Utility Maximization for Smart Grid

    In this paper, the authors consider a smart power infrastructure, where several subscribers share a common energy source. Each subscriber is equipped with an Energy Consumption Controller (ECC) unit as part of its smart meter. Each smart meter is connected to not only the power grid but also a communication...

    Provided By University of British Columbia

  • White Papers // Aug 2009

    Anonymous Cardinality Estimation in RFID Systems With Multiple Readers

    In this paper, the authors study the anonymous cardinality estimation problem in Radio Frequency IDentification (RFID) systems. To preserve privacy and anonymity, each tag only transmits a portion of its ID to the reader when it is being queried. To achieve complete system coverage and increase the accuracy of measurement,...

    Provided By University of British Columbia

  • White Papers // Aug 2010

    Content Caching and Replication Schemes for Peer-to-Peer File Sharing in Wireless Mesh Networks

    Wireless Mesh Networks (WMNs) have emerged as an important technology in building next generation fixed wireless broadband networks that provide low cost Internet access for fixed and mobile users. An orthogonal evolution in computer networking has been the rise of Peer-to-Peer (P2P) applications such as P2P file sharing. It is...

    Provided By University of British Columbia

  • White Papers // Jul 2011

    Design of Pre-Rake DS-UWB Downlink With Pre-Equalization

    The authors consider the design of Ultra-WideBand (UWB) systems that enable high data rate communications for short-range wireless applications. In particular, they consider the downlink of a Direct Sequence UWB (DS-UWB) system in which the base station is equipped with multiple antennas and employs pre-rake combining, while each user employs...

    Provided By University of British Columbia

  • White Papers // Apr 2011

    On Cooperative Coding for Narrowband PLC Networks

    Low-Frequency NarrowBand (LF NB) Power Line Communications (PLC) is an old data-communication concept that has received renewed interest in industry, standardization, and academia for its potential to become an important element of the communication infrastructure supporting Smart Grid applications. In this paper, dedicated to Prof. Johannes Huber on the occasion...

    Provided By University of British Columbia

  • White Papers // Feb 2011

    Dynamic Decode-and-Forward Relaying Using Raptor Codes

    Dynamic Decode-and-Forward (DDF) is a version of decode-and-forward relaying in which the duration of the listening phase at relays is not fixed. In this paper, the authors investigate half-duplex DDF relaying based on rateless codes. The use of rateless codes allows relays to autonomously switch from listening to the source...

    Provided By University of British Columbia

  • White Papers // Sep 2010

    Bit-Interleaved Coded Modulation With Mismatched Decoding Metrics

    Bit-Interleaved Coded Modulation (BICM) has become the de facto coding standard for communication systems. Recently, BICM has been cast as a mismatched decoding scheme due to the assumption of independent bit metrics. In addition to this inherent mismatch, practical demodulators may produce mismatched decoding metrics because of implementation constraints, such...

    Provided By University of British Columbia

  • White Papers // Jan 2010

    Opportunistic Spectral Access Through Suppression of Impulsive Interference

    Cognitive radios are slated to be the next generation of smart transceivers that can opportunistically access spectrum through dynamic sensing of their immediate Radio Frequency (RF) environment. Such spectral sharing will be limited primarily by the interference that a cognitive user may potentially cause to the licensed primary user of...

    Provided By University of British Columbia

  • White Papers // Aug 2009

    An Analytical Approach for Performance Evaluation of BICM Transmission over Nakagami-m Fading Channels

    Bit-Interleaved Coded Modulation (BICM) has established itself as a quasi-standard for bandwidth- and power-efficient wireless communication. In this paper, the authors present an analytical approach to evaluate the performance of BICM transmission over frequency-flat fading additive white Gaussian noise channels. The statistic of the fading envelope is modeled as Nakagami-m...

    Provided By University of British Columbia

  • White Papers // Aug 2009

    A Compressed Sensing Receiver for UWB Impulse Radio in Bursty Applications Like Wireless Sensor Networks

    The authors propose a novel receiver for Ultra-Wide-band Impulse-Radio communication in Wireless Sensor Networks, which are characterized by bursty traffic and severe power constraints. The receiver is based on the principle of Compressed Sensing, and exploits the sparsity of the transmitted signal to achieve reliable demodulation from a relatively small...

    Provided By University of British Columbia

  • White Papers // Mar 2009

    An RL-Based Scheduling Algorithm for Video Traffic in High-Rate Wireless Personal Area Networks

    The emerging high-rate Wireless Personal Area Network (WPAN) technology is capable of supporting high-speed and high-quality real-time multimedia applications. In particular, video streams are deemed to be a dominant traffic type, and require Quality of Service (QoS) support. However, in the current IEEE 802.15.3 standard for MAC (Media Access Control)...

    Provided By University of British Columbia

  • White Papers // Jun 2011

    Profiling-as-a-Service: Adaptive Scalable Resource Profiling for the Cloud in the Cloud

    Run-time profiling of Web-based applications and services is an effective method to aid in the provisioning of required resources, for monitoring server-level objectives, and for detecting implementation defects. Unfortunately, it is difficult to obtain accurate profile data on live client workloads due to the high overhead of instrumentation. This paper...

    Provided By University of British Columbia

  • White Papers // May 2011

    Exposing File System Mappings With MapFS

    The conventional model of a file as a contiguous array of bytes hides information about the physical location of data from users. While this simplifying abstraction can be useful in some cases, it can also lead to suboptimal performance and unnecessary overhead. A growing number of applications - even those...

    Provided By University of British Columbia

  • White Papers // Nov 2008

    Block Mason

    Hardware virtualization gives administrators the flexibility to rapidly create, destroy and relocate virtual machines across physical hosts. Unfortunately, the storage systems upon which these systems depend are not nearly as agile. To facilitate the rapid, safe development of block devices that can meet the needs of virtual machines, the authors...

    Provided By University of British Columbia

  • White Papers // Jun 2009

    Modeling Post-Techmapping and Post-Clustering FPGA Circuit Depth

    This paper presents an analytical model that relates FPGA architectural parameters to the expected speed of FPGA implementation. More precisely, the model relates the lookup-table size, cluster size, and number of inputs per cluster to the depth of the circuit after technology mapping and after clustering. Comparison to experimental results...

    Provided By University of British Columbia

  • White Papers // Jun 2009

    Modeling the Relationship Between FPGA Architecture and Place and Route Runtime

    This paper presents an analytical model that relates the architectural parameters of an FPGA to the place-and-route runtimes of the FPGA CAD tools. The authors consider both a simulated annealing based placement algorithm employing a bounding-box wire-length cost function, and a negotiation-based A router. They also show an example application...

    Provided By University of British Columbia

  • White Papers // Sep 2008

    A System-Level Stochastic Circuit Generator for FPGA Architecture Evaluation

    The authors describe a stochastic circuit generator that can be used to automatically create benchmark circuits for use in FPGA architecture studies. The circuits consist of a hierarchy of interconnected modules, reflecting the structure of circuits designed using a system-on-chip design flow. Within each level of hierarchy, modules can be...

    Provided By University of British Columbia

  • White Papers // Jul 2009

    Simultaneous PVT-Tolerant Voltage-Island Formation and Core Placement for Thousand-Core Platforms

    In this paper, the authors propose a novel approach to voltage island formation and core placement for energy optimization in many-core architectures under parameter variations at pre-fabrication stage. They group the cores into irregular "Cloud-shaped" voltage islands. The islands are created by balancing the desire to limit the spatial extent...

    Provided By University of British Columbia

  • White Papers // Apr 2009

    Charge-Borrowing Decap: A Novel Circuit for Removal of Local Supply Noise Violations

    The authors propose a novel circuit called Charge-Borrowing Decap (CBD) as a drop-in replacement for passive decaps to reduce supply noise for removal of "Hot-spot" IR-drop problems found late in the design process. Measurement results on a 90nm test chip show that a noise reduction improvement between 42%-55% at 100MHz-1.5GHz...

    Provided By University of British Columbia

  • White Papers // Sep 2011

    Neighborhood-Knowledge Based Routing in PLC

    One of the challenges of employing Power Line Communication (PLC) in power distribution grids is routing messages using multihop transmission or, in other words, by relaying information through decode and forward packets. In this contribution, the authors show a possible compromise between energy consumption and delivery delay that are performance...

    Provided By University of British Columbia

  • White Papers // Sep 2011

    Inferring Power Line Network Topology Using Frequency Domain Reflectometry

    Power Line Communications (PLC) is an attractive means of data communication for a variety of scenarios and applications, including in-home multimedia and utility applications, the latter of which have gained renewed attention under the label of Smart Grid. The analysis and design of PLC systems should rely on sufficiently accurate...

    Provided By University of British Columbia

  • White Papers // Oct 2009

    Conditional Risk And Performance Evaluation: Volatility Timing, Overconditioning, And New Estimates Of Momentum Alphas

    Unconditional alpha estimates are biased when conditional beta covaries with the market risk premium ("Market-timing") or volatility ("Volatility-timing"). Whereas prior literature focuses on market-timing, the authors demonstrate that volatility-timing has a plausible impact 2 to 10 times larger. Moreover, they identify a novel and potentially substantial bias ("Overconditioning") that can...

    Provided By University of British Columbia

  • White Papers // May 2009

    Consumption Volatility Risk

    Empirically, the conditional volatility of aggregate consumption growth varies over time. While many papers test the consumption CAPM based on realized consumption growth, little is known about how the time-variation of consumption growth volatility affects asset prices. The authors show that in a model where the agent has recursive preferences,...

    Provided By University of British Columbia

  • White Papers // Aug 2010

    Pyramidal Ownership And The Creation Of New Firms

    The authors study the role of pyramidal ownership in the creation of new firms using a comprehensive panel of manufacturing firms in Europe. Pyramidal ownership structures are used to supply inside funds to new firms that are unable to raise enough external financing, namely, those with large investment requirements and...

    Provided By University of British Columbia