Boston University

Displaying 1-40 of 168 results

  • White Papers // Jun 2014

    Distributed Real-Time Fault Tolerance on a Virtualized Multi-Core System

    In this paper, the authors present different approaches for real-time fault tolerance using redundancy methods for multi-core systems. Using hardware virtualization, a distributed system on a chip is created, where the cores are isolated from one another except through explicit communication channels. Using this system architecture, redundant tasks that would...

    Provided By Boston University

  • White Papers // May 2014

    Learning Modular Structures from Network Data and Node Variables

    A standard technique for understanding underlying dependency structures among a set of variables posits a shared conditional probability distribution for the variables measured on individuals within a group. This approach is often referred to as module networks, where individuals are represented by nodes in a network, groups are termed modules,...

    Provided By Boston University

  • White Papers // Mar 2014

    Profiling EEMBC MultiBench Programs Using Full-System Simulations

    In this paper, the authors present the profiling of EEMBC parallel benchmark programs that is designed for the evaluation and future development of scalable SMP architectures. Modern Multi-Processor System-on-Chip (MPSoC) includes tens of IP blocks, such as CPUs, memories, input/output devices, and HW accelerators,. Figure 1 shows an example of...

    Provided By Boston University

  • White Papers // Jan 2014

    Strategies for Anticipating Risk in Heterogeneous System Design

    Heterogeneous design presents an opportunity to improve energy efficiency but raises a challenge in resource management. Prior design methodologies aim for performance and efficiency, yet a deployed system may miss these targets due to run-time effects, which the authors denote as risk. They propose design strategies that explicitly aim to...

    Provided By Boston University

  • White Papers // Jan 2014

    On the Integration of Real-time Asynchronous Event Handling Mechanisms with Existing Operating System Services

    In this paper, the authors present an asynchronous event handling mechanism for real-time applications that leverages existing system services in COTS systems. In their implementation, event dispatching is initiated within bottom-half interrupt handling routines, in order to support predictable, safe, and efficient event handling functionality at user-level. They compare their...

    Provided By Boston University

  • White Papers // Jan 2014

    Quest-V: A Virtualized Multikernel for High-Confidence Systems

    In this paper, the authors outline the design of 'Quest-V', which is implemented as a collection of separate kernels operating together as a distributed system on a chip. Quest-V uses virtualization techniques to isolate kernels and prevent local faults from affecting remote kernels. This leads to a high-confidence multikernel approach,...

    Provided By Boston University

  • White Papers // Jan 2014

    Mutable Protection Domains: Towards a Component-based System for Dependable and Predictable Computing

    The increasing complexity of software poses significant challenges for real-time and embedded systems beyond those based purely on timeliness. With embedded systems and applications running on everything from mobile phones, PDAs, to automobiles, aircraft and beyond, an emerging challenge is to ensure both the functional and timing correctness of complex...

    Provided By Boston University

  • White Papers // Oct 2013

    The Quest-V Separation Kernel for Mixed Criticality Systems

    Embedded systems are increasingly featuring multi and many-core processors, due in part to their power, performance and price benefits. These processors offer new opportunities for an increasingly significant class of mixed criticality systems. In mixed criticality systems, there is a combination of application and system components with different safety and...

    Provided By Boston University

  • White Papers // Sep 2013

    Optimizing Communication and Cooling Costs in HPC Data Centers via Intelligent Job Allocation

    Nearly half of the energy in the computing clusters today is consumed by the cooling infrastructure. It is possible to reduce the cooling cost by allowing the data center temperatures to rise; however, component reliability constraints impose thermal thresholds as failure rates are exponentially dependent on the processor temperatures. Existing...

    Provided By Boston University

  • White Papers // Aug 2013

    Autonomous Resource Sharing for Multi-Threaded Workloads in Virtualized Servers

    Multi-threaded applications from many application domains have started to appear on the cloud resources. Multi-threaded applications bring additional challenges to the management of the cloud resources, due to characteristics such as inter/intra-thread communication. In tandem, as the energy spent on computing continues to increase, the ability to provide energy-performance tradeoffs...

    Provided By Boston University

  • White Papers // Aug 2013

    Dynamic Server Power Capping for Enabling Data Center Participation in Power Markets

    Today's US power markets offer new opportunities for the energy consumers to reduce their energy costs by first promising an average consumption rate for the next hour and then by following a regulation signal broadcast by the Independent System Operators (ISOs), who need to match supply and demand in real...

    Provided By Boston University

  • White Papers // Jul 2013

    Dynamic Cache Pooling for Improving Energy Efficiency in 3D Stacked Multicore Processors

    Resource pooling, where multiple architectural components are shared among multiple cores, is a promising technique for improving the system energy efficiency and reducing the total chip area. 3D stacked multicore processors enable efficient pooling of cache resources owing to the short interconnect latency between vertically stacked layers. This paper introduces...

    Provided By Boston University

  • White Papers // Jun 2013

    vCap: Adaptive Power Capping for Virtualized Servers

    Power capping on server nodes has become an essential feature in data centers for controlling energy costs and peak power consumption. More than half of the server nodes are virtualized in today's data centers; thus, providing a practical power capping technique for consolidated virtual environments is a significant research problem....

    Provided By Boston University

  • White Papers // Jun 2013

    Navigating Heterogeneous Processors with Market Mechanisms

    As datacenters proliferate and access to them is democratized, increasingly diverse cloud applications will demand computation. To accommodate the rise in demand, traditional datacenter servers have relied on Moore's Law. This strategy is insufficient as Dennard scaling ends and constrains the power efficiency of processor servers. Instead of relying on...

    Provided By Boston University

  • White Papers // Feb 2013

    Intra-Car Wireless Sensors Data Collection: A Multi-Hop Approach

    The authors experimentally investigate the benefits of multi-hop networking for intra-car data aggregation under the current state-of-the-art Collection Tree Protocol (CTP). They show how this protocol actively adjusts collection routes according to channel dynamics in various practical car environments, resulting in performance gains over single-hop aggregation. Throughout their experiments, they...

    Provided By Boston University

  • White Papers // Jan 2013

    Real-Time USB Communication in the Quest Operating System

    In this paper, the authors describe a real-time USB 2 subsystem for the quest operating system. Quest is designed for real-time embedded systems. Such systems need to interact with their environment using sensors and actuators. On many embedded platforms today there is support for basic serial, USB 2.0 and 100...

    Provided By Boston University

  • White Papers // Jan 2013

    CCM: Scalable, On-Demand Compute Capacity Management for Cloud Datacenters

    Multi-tenant cloud computing datacenters run diverse workloads with time varying resource demands. This continuously leads to areas of high and low resource utilization throughout the cloud infrastructure. The authors present CCM (Cloud Capacity Manager) - a prototype system, and, methods for dynamically multiplexing the compute capacity of cloud datacenters at...

    Provided By Boston University

  • White Papers // Jan 2013

    Probabilistic Indoor Tracking of Mobile Wireless Nodes Relative to Landmarks

    The profile-based approach is known to be advantageous when it comes to inferring positions of mobile wireless devices in complex indoor environments. The past decade has seen a significant body of work that explores different implementations of this approach, with varying degrees of success. Here, the authors cast the profile-based...

    Provided By Boston University

  • White Papers // Jan 2013

    Spatio-Temporal Network Anomaly Detection by Assessing Deviations of Empirical Measures

    The authors introduce an Internet traffic anomaly detection mechanism based on large deviations results for empirical measures. Using past traffic traces they characterize network traffic during various time-of-day intervals, assuming that it is anomaly-free. They present two different approaches to characterize traffic: a model-free approach based on the method of...

    Provided By Boston University

  • White Papers // Dec 2012

    Verifying Search Results Over Web Collections

    Web searching accounts for one of the most frequently performed computations over the Internet as well as one of the most important applications of outsourced computing, producing results that critically affect users' decision-making behaviors. As such, verifying the integrity of Internet-based searches over vast amounts of web contents is essential....

    Provided By Boston University

  • White Papers // Sep 2012

    A Two Phase Hybrid RSS/AoA Algorithm for Indoor Device Localization Using Visible Light

    A two phase hybrid algorithm for estimating the location of a mobile node, which has the capability of measuring signal strength, azimuth, and elevation, in a smart space environment over the visible light channel is proposed. In contrast to conventional triangulation approaches which are performed in a simplified plane, the...

    Provided By Boston University

  • White Papers // Sep 2012

    Dynamic Pricing of Preemptive Service for Elastic Demand

    The authors consider a service provider that accommodates two classes of users: Primary Users (PUs) and Secondary Users (SUs). SU demand is elastic to price whereas PU demand is inelastic. When a PU arrives to the system and finds all channels busy, it preempts an SU unless there are no...

    Provided By Boston University

  • White Papers // Aug 2012

    Scheduling Mobile Nodes for Cooperative Data Transport in Sensor Networks

    Message Ferrying has been shown to be an effective approach to support routing in sparse ad hoc or sensor networks. Considering a generic network model where each node in the network wishes to send data to some (or possibly all) other nodes with known (and possibly different) rates, the authors...

    Provided By Boston University

  • White Papers // Aug 2012

    Optimal Admission Control in Two-Class Preemptive Loss Systems

    The authors study optimal admission control in a two-class preemptive loss system. A class-1 customer arrival aborts service of a class-2 customer if the system is full upon arrival. Each successfully serviced class-2 customer leads to a reward, whereas each aborted class-2 customer incurs a cost. Using dynamic programming, they...

    Provided By Boston University

  • White Papers // Aug 2012

    Online Pricing of Secondary Spectrum Access With Unknown Demand Function

    The authors consider a wireless provider who caters to two classes of customers, namely Primary Users (PUs) and Secondary Users (SUs). PUs has long term contracts while SUs are admitted and priced according to current availability of excess spectrum. The average rate at which SUs attempt to access the spectrum...

    Provided By Boston University

  • White Papers // Aug 2012

    Competition in Secondary Spectrum Markets: Price War or Market Sharing?

    Recent initiatives allow cellular providers to offer spot service of their licensed spectrum, paving the way to dynamic secondary spectrum markets. This paper characterizes market outcomes when multiple providers are drawn into competition for secondary demand. The authors study a game-theoretic model in which each provider aims to enhance its...

    Provided By Boston University

  • White Papers // Aug 2012

    Prioritized Data Synchronization for Disruption Tolerant Networks

    The authors consider the problem of synchronizing prioritized data on two distinct hosts in Disruption-Tolerant Networks (DTNs). To this effect, they propose and analyze a new interactive protocol for priority-oriented synchronization, called P-CPI that is especially efficient in terms of bandwidth usage. This middleware protocol has features that are particularly...

    Provided By Boston University

  • White Papers // Jul 2012

    Profit-Robust Policies for Dynamic Sharing of Radio Spectrum

    The authors investigate profitability from secondary spectrum provision under unknown relationships between price charged for spectrum use and demand drawn at the given price. They show that profitability is governed by the applied admission policy and the price charged to secondary users. They explicitly identify a critical price (market entry...

    Provided By Boston University

  • White Papers // Jul 2012

    Economic Viability of Private Commons: Framework and Guidelines for Profitability

    Ongoing regulatory reforms have led to several novel spectrum sharing models under the general umbrella of dynamic spectrum sharing. The private commons model introduced by FCC in 2004 allows spectrum licensees to provide secondary access to spectrum on an opportunistic basis while retaining ownership. Since wireless communication systems are typically...

    Provided By Boston University

  • White Papers // Jul 2012

    Jamming-Resistant Rate Control in Wi-Fi Networks

    Recent experimental studies reveal that several well-known and widely deployed Rate Adaptation Algorithms (RAAs) in 802.11 WLANs are vulnerable to selective jamming attacks. However, previous work resorts to complex jamming strategies that are hard to implement and does not provide applicable solutions to this problem. In this paper, the authors...

    Provided By Boston University

  • White Papers // Jun 2012

    Posit: A Lightweight Approach for IP Geolocation

    Location-specific Internet services are predicated on the ability to identify the geographic position of IP hosts accurately. Fundamental to current state-of-the-art geolocation techniques is reliance on heavyweight traceroute-like probes that put a significant traffic load on networks. In this paper, the authors introduce a new lightweight approach to IP geolocation...

    Provided By Boston University

  • White Papers // Jun 2012

    Adaptive Energy-Efficient Resource Sharing for Multi-threaded Workloads in Virtualized Systems

    Computational demand on today's data centers is continuously increasing, as computing trends are shifting towards the cloud. The corresponding increases in energy consumption and management complexity remain as major challenges for data centers. Server virtualization provides opportunities to improve energy efficiency by reducing the number of physical servers through workload...

    Provided By Boston University

  • White Papers // Jun 2012

    Time Management in the Quest-V RTOS

    Quest-V is a new system currently under development for multicore processors. It comprises a collection of separate kernels operating together as a distributed system on a chip. Each kernel is isolated from others using virtualization techniques, so that faults do not propagate throughout the entire system. This multikernel design supports...

    Provided By Boston University

  • White Papers // Apr 2012

    Optimal Admission Control of Secondary Users in Preemptive Cognitive Radio Networks

    The authors study optimal admission control of Secondary Users (SUs) in Cognitive Radio (CR) networks in presence of preemption. In this model, when a Primary User (PU) arrives to the system and finds all the channels busy, it preempts an SU unless all the users in the system are PUs....

    Provided By Boston University

  • White Papers // Apr 2012

    Universally Composable Security With Local Adversaries

    The traditional approach to formalizing ideal-model based definitions of security for multi-party protocols model adversaries (both real and ideal) as centralized entities that control all parties that deviate from the protocol. While this centralized-adversary modeling suffices for capturing basic security properties such as secrecy of local inputs and correctness of...

    Provided By Boston University

  • White Papers // Apr 2012

    On Delay-Minimized Data Harvesting With Mobile Elements in Wireless Sensor Networks

    The authors consider the problem of routing and scheduling a set of mobile elements that act as mechanical carriers of data, harvesting them from sensor nodes and delivering them to a sink. The objective is to minimize the data delivery latency. Most of the existing work has focused on designing...

    Provided By Boston University

  • White Papers // Mar 2012

    Connected Identifying Codes

    The authors consider the problem of generating a connected identifying code for an arbitrary graph. After a brief motivation, they show that the decision problem regarding the existence of such a code is NP-complete, and they propose a novel polynomial-time approximation ConnectID that transforms any identifying code into a connected...

    Provided By Boston University

  • White Papers // Mar 2012

    Performance and Power Analysis of RCCE Message Passing on the Intel Single-Chip Cloud Computer

    The number of cores integrated on a single chip increases with each generation of computers. Traditionally, a single Operating System (OS) manages all the cores and resource allocation on a multi-core chip. Intel's Single-chip Cloud Computer (SCC), a manycore processor built for research use with 48 cores, is an implementation...

    Provided By Boston University

  • White Papers // Feb 2012

    Reliable Rateless Wireless Broadcasting With Near-Zero Feedback

    The authors examine the problem of minimizing feedback in reliable wireless broadcasting, by pairing rateless coding with extreme value theory. Their key observation is that, in a broadcast environment, this problem resolves into estimating the maximum number of packets dropped among many receivers rather than for each individual receiver. With...

    Provided By Boston University

  • White Papers // Feb 2012

    Scheduling Algorithms and Bounds for Rateless Data Dissemination in Dense Wireless Networks

    Many applications in wireless cellular networks rely on the ability of the network to reliably and efficiently disseminate data to a large client audience. The stochastic nature of packet loss across receivers and channel interference constraints between cells complicate this task, however. In this paper, the authors analyze the problem...

    Provided By Boston University

  • White Papers // Jan 2011

    iJoin: Importance-Aware Join Approximation Over Data Streams

    The authors consider approximate join processing over data streams when memory limitations cause incoming tuples to overflow the available space, precluding exact processing. Selective eviction of tuples (load-shedding) is needed, but is challenging since data distributions and arrival rates are unknown a priori. Also, in many real-world applications such as...

    Provided By Boston University

  • White Papers // Feb 2010

    Scale Invariant Properties Of Public Debt Growth

    Public debt is one of the important economic variables that quantitatively describe a nation's economy. Because bankruptcy is a risk faced even by institutions as large as governments (e.g. Iceland), national debt should be strictly controlled with respect to national wealth. Also, the problem of eliminating extreme poverty in the...

    Provided By Boston University

  • White Papers // Dec 2009

    The Structure And Growth Of Weighted Networks

    The authors develop a simple theoretical framework for the evolution of weighted networks that is consistent with a number of stylized features of real-world data. In the framework, the Barabasi-Albert model of network evolution is extended by assuming that link weights evolve according to a geometric Brownian motion. The model...

    Provided By Boston University

  • White Papers // Oct 2010

    Communicating Technical Knowledge

    In patent theory, the cost of communicating technical knowledge is small. In human capital theory, it is large. But evidence suggests that these costs are actually endogenous. Firms invest in reducing communication costs, but only when technology is sufficiently advanced. This can make competition different for early stage technologies: patents...

    Provided By Boston University

  • White Papers // Nov 2010

    Bankruptcy Risk Model And Empirical Tests

    The authors analyze the size-dependence and temporal stability of firm bankruptcy risk in the US economy by applying Zipf scaling techniques. They focus on a single risk factor - the debt-to-asset ratio R - in order to study the stability of the Zipf distribution of R over time. They find...

    Provided By Boston University

  • White Papers // Mar 2011

    A Copula Approach On The Dynamics Of Statistical Dependencies In The US Stock Market

    The authors analyze the statistical dependency structure of the S&P 500 constituents in the 4-year period from 2007 to 2010 using intraday data from the New York Stock Exchange's TAQ database. With a copula-based approach, they find that the statistical dependencies are very strong in the tails of the marginal...

    Provided By Boston University

  • White Papers // Jan 2011

    Basis Token Consistency: Supporting Strong Web Cache Consistency

    With web caching and cache-related services like CDNs and edge services playing an increasingly significant role in the modern Internet, the problem of the weak consistency and coherence provisions in current web protocols is drawing increasing attention. Toward this end, the authors differentiate definitions of consistency and coherence for web-like...

    Provided By Boston University

  • White Papers // Feb 2011

    Quantifying And Modeling Long-range Cross-correlations In Multiple Time Series With Applications To World Stock Indices

    The authors propose a modified time lag random matrix theory in order to study time lag cross-correlations in multiple time series. They apply the method to 48 world indices, one for each of 48 different countries. They find long-range power-law cross-correlations in the absolute values of returns that quantify risk,...

    Provided By Boston University

  • White Papers // May 2011

    A Domain-Specific Language for the Incremental and Modular Design of Large-Scale Verifiably-Safe Flow Networks

    Flow networks are inductively defined, assembled from small networks or modules to produce arbitrarily large ones, with interchangeable functionally-equivalent parts. The authors carry out this induction formally using a Domain-Specific Language (DSL). Associated with the authors' DSL is a typing system (or static semantics), a system of formal annotations that...

    Provided By Boston University

  • White Papers // Feb 2011

    The Filter-Placement Problem and Its Application to Content De-Duplication

    In many information networks, data items - such as updates in social networks, news flowing through interconnected RSS feeds and blogs, measurements in sensor networks, route updates in ad-hoc networks, etc. - propagate in an uncoordinated manner: nodes often relay information they receive to neighbors, independent of whether or not...

    Provided By Boston University

  • White Papers // Jan 2010

    Does Lumpy Investment Matter For Business Cycles?

    The authors present an analytically tractable general equilibrium business cycle model that features micro-level investment lumpiness. They prove an exact irrelevance proposition which provides sufficient conditions on preferences, technology, and the fixed cost distribution such that any positive upper support of the fixed cost distribution yields identical equilibrium dynamics of...

    Provided By Boston University

  • White Papers // Sep 2010

    Credit Risk And Business Cycles

    The authors incorporate long-term defaultable corporate bonds and credit risk in a dynamic stochastic general equilibrium business cycle model. Credit risk amplifies aggregate technology shocks. The debt-capital ratio is a new state variable and its endogenous movements provide a propagation mechanism. The model can match the persistence and volatility of...

    Provided By Boston University

  • White Papers // Jun 2010

    On The Dynamics Of Unemployment And Wage Distributions

    Postel-Vinay and Robin's (2002) sequential auction model is extended to allow for aggregate productivity shocks. Workers exhibit permanent differences in ability while firms are identical. Negative aggregate productivity shocks induce job destruction by driving the surplus of matches with low ability workers to negative values. Endogenous job destruction coupled with...

    Provided By Boston University

  • White Papers // Feb 2011

    Entangled Financial Systems

    This paper analyzes counterparty risk in entangled financial systems in which banks hedge risks using a network of bilateral over-the-counter contracts. If banks have large exposures to a few counterparties, they do not buy insurance against a low probability counterparty default even though it is socially desirable. This is because...

    Provided By Boston University

  • White Papers // Oct 2009

    Impact of Asymmetric Traffic Densities on Delay Tolerant Vehicular Ad Hoc Networks

    Vehicular networking can be achieved with short, medium, or long-range communication technologies. However, there are trade-offs in the adoption of these technologies including data capacity, continuity of connections, energy use and contention with other users. The authors focus on short range technologies that support both near-neighbor communication, for safety applications,...

    Provided By Boston University

  • White Papers // Jan 2011

    Virtual-CPU Scheduling in the Quest Operating System

    This paper describes the scheduling framework for a new operating system called "Quest." The three main goals of Quest are to ensure safety, predictability and efficiency of software execution. For this paper, the authors focus on one aspect of predictability, involving the integrated management of tasks and I/O events such...

    Provided By Boston University

  • White Papers // May 2011

    Inverse Compute-and-Forward: Extracting Messages From Simultaneously Transmitted Equations

    The authors consider the transmission of independent messages over a Gaussian relay network with interfering links. Using the compute-and-forward framework, relays can efficiently decode equations of the transmitted messages. The relays can then send their collected equations to the destination, which solves for its desired messages. Here, they study a...

    Provided By Boston University

  • White Papers // Aug 2011

    Phase Transition of Message Propagation Speed in Delay Tolerant Vehicular Networks

    Delay Tolerant Network (DTN) architectures have recently been proposed as a means to enable efficient routing of messages in Vehicular Area NETworks (VANETs), which are characterized by alternating periods of connectivity and disconnection. Under such architectures, when multi-hop connectivity is available, messages propagate at the speed of radio over connected...

    Provided By Boston University

  • White Papers // Jul 2010

    Reservation Policies for Revenue Maximization From Secondary Spectrum Access in Cellular Networks

    The authors consider the problem of providing opportunistic spectrum access to secondary users in wireless cellular networks. From the standpoint of spectrum license holders, achieving benefits of secondary access entails balancing the revenue from such access and its impact on the service of primary users. While dynamic optimization is a...

    Provided By Boston University

  • White Papers // Sep 2009

    Asymptotically Optimal Data Dissemination in Multi-Channel Wireless Sensor Networks: Single Radios Suffice

    The authors analyze the performance limits of data dissemination with multi-channel, single radio sensors under random packet loss. They formulate the problem of minimizing the average delay of data dissemination as a stochastic shortest path problem and show that, for an arbitrary topology network, an optimal control policy can be...

    Provided By Boston University

  • White Papers // Jan 2011

    Asymptotically Optimal Transmission Policies for Large-Scale Low-Power Wireless Sensor Networks

    The authors consider wireless sensor networks with multiple gateways and multiple classes of traffic carrying data generated by different sensory inputs. The objective is to devise joint routing, power control and transmission scheduling policies in order to gather data in the most efficient manner while respecting the needs of different...

    Provided By Boston University

  • White Papers // Dec 2010

    Connected Identifying Codes for Sensor Network Monitoring

    Identifying codes have been proposed as an abstraction for implementing monitoring tasks such as indoor localization using wireless sensor networks. In this approach, sensors' radio coverage overlaps in unique ways over each identifiable region, according to the codewords of an identifying code. While connectivity of the underlying identifying code is...

    Provided By Boston University

  • White Papers // Dec 2009

    Reliable Wireless Broadcasting With Near-Zero Feedback

    The authors examine the problem of minimizing feedbacks in reliable wireless broadcasting, by pairing rateless coding with extreme value theory. Their key observation is that, in a broadcast environment, this problem resolves into estimating the maximum number of packets dropped among many receivers rather than for each individual receiver. With...

    Provided By Boston University

  • White Papers // Dec 2009

    On-Line Pricing of Secondary Spectrum Access With Unknown Demand Function and Call Length Distribution

    The authors consider a wireless provider who caters to two classes of customers, namely primary and secondary users. Primary users have long term contracts while secondary users are admitted and priced according to current availability of excess spectrum. Secondary users accept an advertised price with a certain probability defined by...

    Provided By Boston University

  • White Papers // Jul 2011

    Gait-Based User Classification Using Phone Sensors

    The authors investigate whether smartphones can be used to distinguish different users based on their gait, the rhythmical body movements of human beings as they walk. To this end, they propose, describe, and experimentally evaluate a system that classifies peoples' gait patterns using the tri-axial accelerometer of the Motorola Droid...

    Provided By Boston University

  • White Papers // Oct 2011

    Handover in VLC Systems With Cooperating Mobile Devices

    Visible Light Communications (VLC) is emerging as viable means to overcome the crowded radio spectrum for highly-localized communications systems. With such an approach, luminaires can be adopted for supporting data communication in addition to illumination in what the authors call Cellular Lighting. However, in these systems, the directionality of light...

    Provided By Boston University

  • White Papers // Jul 2011

    A V2X-Based Approach for Reduction of Delay Propagation in Vehicular Ad-Hoc Networks

    In this paper, the authors investigate the time delay propagation rates in a Vehicular Ad-Hoc Network, where vehicular connectivity is supported by both Vehicle-To-Vehicle (V2V) and Vehicle-To-Infrastructure (V2I) protocols. In their vision, seamless connectivity issues in a VANET with nearby network infrastructure, can be fixed by an opportunistic choice of...

    Provided By Boston University

  • White Papers // May 2010

    Role of Directional Wireless Communication in Vehicular Networks

    Enabling safety in vehicles is an ongoing challenge for the automotive sector. One approach towards enhancing safety is to increase knowledge within a vehicle of the actions of vehicles in the vicinity. Increased awareness is essential for activating the safety systems to take evasive or precautionary actions in the event...

    Provided By Boston University

  • White Papers // May 2010

    A Message Propagation Model for Hybrid Vehicular Communication Protocols

    This paper addresses a hybrid approach on message propagation in vehicular networks. Short-range Vehicle-To-Vehicle (V2V) communications cannot always guarantee connectivity to the network cloud, especially when traffic density is very low. By utilizing existing wireless network infrastructure it is possible to greatly enhance the capabilities of short range V2V technologies....

    Provided By Boston University

  • White Papers // Mar 2010

    QoS-Enabled Video Streaming in Wireless Sensor Networks

    Recent advances in wireless communications technology and low-power, low-cost CMOS imaging sensors enable a new sensing modality employing ubiquitous distributed video sensing. In many video sensing applications multimedia streams are often required by the base station to provide detailed information of the target spot in the sensor field. However, limited...

    Provided By Boston University

  • White Papers // May 2010

    Throughput Estimation for Singleton Video Streaming Application Over Wireless Sensor Network

    Recent advances in wireless communications technology and low-power, low-cost CMOS imaging sensors enable a new sensing modality employing ubiquitous distributed video sensing. In many video sensing applications multimedia streams are often required by the base station to provide detailed information of the target spot in the sensor field. Such applications...

    Provided By Boston University

  • White Papers // Oct 2009

    PhD Forum: Routing Protocol and Performance Modeling in Delay Tolerant Vehicular Networks

    Development of networking protocols is essential for an emerging class of applications described as Vehicular Ad hoc NETworks (VANETs). The scope and requirements of applications vary significantly, and existing techniques do not apply. The nature of data exchange varies in time and space and thus, the protocols need to accommodate...

    Provided By Boston University

  • White Papers // Oct 2009

    On Fair Sharing of Spectrum Via CSMA

    The authors contrast CSMA and TDMA schemes for medium access in spatially dispersed wireless networks under the primary interference model. CSMA is based on random access via dynamically tuned parameters, whereas TDMA involves periodic bursts that are offset in time so as to avoid packet collisions. They study TDMA in...

    Provided By Boston University

  • White Papers // Feb 2011

    Profitability of Dynamic Spectrum Provision for Secondary Use

    The authors characterize policies and prices for secondary spectrum provision whose profitability is insensitive to the demand curve. In more explicit terms, the paper provides a critical price value such that if secondary access is priced above that value then allowing secondary access is profitable for the licensee as long...

    Provided By Boston University

  • White Papers // Aug 2009

    Pricing Strategies for Spectrum Lease in Secondary Markets

    The authors develop analytical models to characterize pricing of spectrum rights in cellular CDMA networks. Specifically, they consider a primary license holder that aims to lease its spectrum within a certain geographic sub-region of its network. Such a transaction has two contrasting economic implications: On the one hand the lessor...

    Provided By Boston University

  • White Papers // Jan 2014

    On the Integration of Real-time Asynchronous Event Handling Mechanisms with Existing Operating System Services

    In this paper, the authors present an asynchronous event handling mechanism for real-time applications that leverages existing system services in COTS systems. In their implementation, event dispatching is initiated within bottom-half interrupt handling routines, in order to support predictable, safe, and efficient event handling functionality at user-level. They compare their...

    Provided By Boston University

  • White Papers // Jan 2007

    Hijack: Taking Control of COTS Systems for Real-Time User-Level Services

    In this paper, the authors focus on a technique to empower Commercial-Off-The-Shelf (COTS) systems with an execution environment, and corresponding services, to support real-time and embedded applications. By leveraging COTS systems, they are able to reduce the potentially expensive maintenance and development costs of proprietary solutions. They describe a system...

    Provided By Boston University

  • White Papers // Oct 2006

    Process-Aware Interrupt Scheduling and Accounting

    In most operating systems, the handling of interrupts is typically performed within the address space of the kernel. Moreover, interrupt handlers are invoked asynchronously during the execution of arbitrary processes. Unfortunately, this allows for a process's time quantum to be consumed by arbitrary interrupt handling. To avoid significant impact to...

    Provided By Boston University

  • White Papers // Jan 2014

    Quest-V: A Virtualized Multikernel for High-Confidence Systems

    In this paper, the authors outline the design of 'Quest-V', which is implemented as a collection of separate kernels operating together as a distributed system on a chip. Quest-V uses virtualization techniques to isolate kernels and prevent local faults from affecting remote kernels. This leads to a high-confidence multikernel approach,...

    Provided By Boston University

  • White Papers // Jun 2014

    Distributed Real-Time Fault Tolerance on a Virtualized Multi-Core System

    In this paper, the authors present different approaches for real-time fault tolerance using redundancy methods for multi-core systems. Using hardware virtualization, a distributed system on a chip is created, where the cores are isolated from one another except through explicit communication channels. Using this system architecture, redundant tasks that would...

    Provided By Boston University