Boston University

Displaying 81-120 of 185 results

  • White Papers // Jan 2011

    An Information Theoretic Framework for Field Monitoring Using Autonomously Mobile Sensors

    The authors consider a mobile sensor network monitoring a spatio-temporal field. Given limited caches at the sensor nodes, the goal is to develop a distributed cache management algorithm to efficiently answer queries with a known probability distribution over the spatial dimension. First, they propose a novel distributed information theoretic approach...

    Provided By Boston University

  • White Papers // Jan 2011

    A Typed Model for Encoding-Based Protocol Interoperability

    Documentation of the HTTP protocol includes precise descriptions of the syntax of the protocol, but lacks similarly precise specification of the semantics of messages and message bodies. Semantics are stated in English prose; while this makes the document more intuitively accessible, it makes any sort of formal claims of correctness...

    Provided By Boston University

  • White Papers // Jan 2011

    Authenticated Index Structures for Outsourced Databases

    In an Outsourced DataBase (ODB) system the database owner publishes data through a number of remote servers, with the goal of enabling clients at the edge of the network to access and query the data more efficiently. As servers might be untrusted or can be compromised, query authentication becomes an...

    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 // 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 // Jan 2011

    Characterizing and Exploiting Reference Locality in Data Stream Applications

    In this paper, the authors investigate a new approach to process queries in data stream applications. They show that reference locality characteristics of data streams could be exploited in the design of superior and flexible data stream query processing techniques. They identify two different causes of reference locality: popularity over...

    Provided By Boston University

  • White Papers // Jan 2011

    Programming With Dependently Typed Data Structures

    The mechanism for declaring datatypes in functional programming languages such as ML and Haskell is of great use in practice. This mechanism, however, often suffers from its imprecision in capturing various invariants inherent in data structures. The introduction of dependent datatypes in Dependent ML (DML) can partly remedy the situation,...

    Provided By Boston University

  • White Papers // Jan 2011

    Dependent Types for Program Termination Verification

    Program termination verification is a challenging research subject of significant practical importance. While there is already a rich body of literature on this subject, it is still undeniably a difficult task to design a termination checker for a realistic programming language that supports general recursion. In this paper, the authors...

    Provided By Boston University

  • White Papers // Jan 2011

    Dependent ML: An Approach to Practical Programming With Dependent Types

    The authors present an approach to enriching the type system of ML with a restricted form of dependent types, where type index terms are required to be drawn from a given type index language that is completely separate from run-time programs, leading to the DML language schema. This enrichment allows...

    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

    Throughput-Competitive Advance Reservation With Bounded Path Dispersion

    In response to the high throughput needs of grid and cloud computing applications, several production networks have recently started to support advance reservation of dedicated circuits. An important open problem within this context is to devise advance reservation algorithms that can provide provable throughput performance guarantees, independently of the specific...

    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 2010

    Monetary Policy, Leverage, And Bank Risk-Taking

    The recent global financial crisis has ignited a debate on whether easy monetary conditions can lead to greater bank risk-taking. The authors study this issue in a model of leveraged financial intermediaries that endogenously choose the riskiness of their portfolios. When banks can adjust their capital structures, monetary easing unequivocally...

    Provided By Boston University

  • White Papers // Dec 2010

    Assessing the Security of a Clean-Slate Internet Architecture

    The TCP/IP architecture was originally designed without taking security measures into consideration. Over the years, it has been subjected to many attacks, which has led to many patches to counter them. The investigations into the fundamental principles of networking have shown that carefully following an abstract model of Inter-Process Communication...

    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 // Oct 2010

    Customizable Keyboard

    Customizable Keyboard is an on-screen keyboard designed to be flexible and expandable. Instead of giving the user a keyboard layout Customizable Keyboard allows the user to create a layout that is accommodating to the user's needs. Customizable Keyboard also allows the user to select from a variety of ways to...

    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 // Oct 2010

    Online Cache Modeling for Commodity Multicore Processors

    Modern Chip-level Multi-Processors (CMPs) contain multiple processor cores sharing a common last-level cache, memory interconnects, and other hardware resources. Workloads running on separate cores compete for these resources, often resulting in highly variable performance. It is generally desirable to co-schedule workloads that have minimal resource contention, in order to improve...

    Provided By Boston University

  • White Papers // Oct 2010

    Exact Analysis of Rate Adaptation Algorithms in Wireless LANs

    Rate adaptation plays a key role in determining the performance of wireless LANs. In this paper, the authors introduce a semi-Markovian framework to analyze the performance of two of the most popular rate adaptation algorithms used in wireless LANs, namely Automatic Rate Fallback (ARF) and Adaptive Automatic Rate Fallback (AARF)....

    Provided By Boston University

  • White Papers // Oct 2010

    On Supporting Mobility and Multihoming in Recursive Internet Architectures

    As the Internet has evolved and grown, an increasing number of nodes (hosts or autonomous systems) have become multihomed, i.e., a node is connected to more than one network. Mobility can be viewed as a special case of multihoming - as a node moves, it unsubscribes from one network and...

    Provided By Boston University

  • White Papers // Oct 2010

    On Unconditionally Secure Computation With Vanishing Communication Cost

    The authors propose a novel distortion-theoretic approach to a secure three-party computation problem. Alice and Bob have deterministic sequences, and Charlie wishes to compute a normalized sum-type function of those sequences. They construct three-party protocols that allow Charlie to compute the function with arbitrarily high accuracy, while maintaining unconditional privacy...

    Provided By Boston University

  • White Papers // Sep 2010

    Trade & Cap: A Customer-Managed, Market-Based System for Trading Bandwidth Allowances at a Shared Link

    This paper proposes Trade & Cap (T&C), an economics-inspired mechanism that incentivizes users to voluntarily coordinate their consumption of the bandwidth of a shared network link so as to converge on what they perceive to be an equitable allocation, while ensuring efficient resource utilization. Under T&C, rather than acting as...

    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 // Aug 2010

    Private Equity Fund Returns: Do Managers Actually Leave Money On The Table?

    Evidence indicates that private equity funds, unlike mutual funds, deliver persistent abnormal returns and that top performing funds are often oversubscribed. Why do private equity funds appear to leave money on the table, rather than, say, increasing fund size and/or fees? The authors argue that private equity funds are fundamentally...

    Provided By Boston University

  • White Papers // Aug 2010

    Angels in the Cloud a Peer-Assisted Bulk-Synchronous Content Distribution Service

    Leveraging client upload capacity through peer-assisted content distribution was shown to decrease the load on content providers, while also improving average distribution times. These benefits, however, are limited by the disparity between client upload and download speeds, especially in scenarios requiring a Minimum Distribution Time (MDT) of a piece of...

    Provided By Boston University

  • White Papers // Aug 2010

    A Modality for Safe Resource Sharing and Code Reentrancy

    The potential of linear logic in facilitating reasoning on resource usage has long been recognized. However, convincing uses of linear types in practical programming are still rather rare. In this paper, the authors present a general design to effectively support practical programming with linear types. In particular, they introduce and...

    Provided By Boston University

  • White Papers // Aug 2010

    Example-Based Image Registration Via Boosted Classifiers

    The authors propose a novel image registration framework which uses classifiers trained from examples of aligned images to achieve registration. The approach is designed to register images of medical data where the physical condition of the patient has changed significantly and image intensities are drastically different. They use two boosted...

    Provided By Boston University

  • White Papers // Aug 2010

    International Risk Cycles

    This paper presents a two-country real business cycle model with two novel features: exogenous shocks to worldwide uncertainty, heterogeneous exposures to the world aggregate shock. The authors show that these two features lead to significant progress in tackling international finance puzzles. When world risk increases, investment decreases and a worldwide...

    Provided By Boston University

  • White Papers // Aug 2010

    Reconstruction and Analysis of 3D Trajectories of Brazilian Free-Tailed Bats in Flight

    The Brazilian free-tailed bat, Tadarida brasiliensis, roosts in very large colonies, consisting of hundreds of thousands of individuals. Each night, bats emerge from their day roosts in dense columns in a highly coordinated manner. The authors recorded short segments of an emergence using three spatially-calibrated and temporally synchronized thermal infrared...

    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 // Jul 2010

    Towards a Multi-Camera Mouse-Replacement Interface

    The authors present the efforts towards a multi-camera mouse-replacement system for computer users with severe motion impairments. They have worked with individuals with cerebral palsy or multiple sclerosis who use a publicly available interface that tracks the user's head movements with a single video camera and translates them into mouse...

    Provided By Boston University

  • White Papers // Jul 2010

    Camera-Based Interfaces and Assistive Software for People With Severe Motion Impairments

    Intelligent assistive technology can greatly improve the daily lives of people with severe paralysis, who have limited communication abilities. People with motion impairments often prefer camera-based communication interfaces, because these are customizable, comfortable, and do not require user-borne accessories that could draw attention to their disability. The authors present an...

    Provided By Boston University

  • White Papers // Jul 2010

    Learning Actions From The Web

    This paper proposes a generic method for action recognition in uncontrolled videos. The idea is to use images collected from the Web to learn representations of actions and use this knowledge to automatically annotate actions in videos. The authors approach is unsupervised in the sense that it requires no human...

    Provided By Boston University

  • White Papers // Jul 2010

    HAIL: Hierarchical Adaptive Interface Layout

    The authors present a framework to adapt software to the needs of individuals with severe motion disabilities who use mouse substitution interfaces. Typically, users are required to adapt to the interfaces that they wish to use. They propose interfaces that change and adapt to the user and their individual abilities....

    Provided By Boston University

  • White Papers // Jul 2010

    A Novel Web-Based Approach for Balancing Usability and Security Requirements of Text Passwords

    Many Internet applications, for example e-commerce or email services require that users create a username and password which serves as an authentication mechanism. Though text passwords have been around for a while, not much has been done in helping naive Internet users in creating strong passwords. Generally users prefer easy-to-remember...

    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 // 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 // May 2010

    A Video Delivery in Wireless Sensor Networks

    Recent advances in wireless communications technology and low-power, low-cost CMOS imaging sensors stimulate research on the analysis and design of ubiquitous video sensing and delivery in wireless sensor networks. However, scalable deployments remain limited or impractical. Critical challenges such as radio interference, limited channel capacity, and constrained energy resources are...

    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 // 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 // Oct 2009

    Safe Compositional Network Sketches: The Formal Framework

    NetSketch is a tool for the specification of constrained-flow applications and the certification of desirable safety properties imposed thereon. NetSketch is conceived to assist system integrators in two types of activities: Modeling and design. As a modeling tool, it enables the of an existing system while retaining sufficient information about...

    Provided By Boston University

  • White Papers // Aug 2009

    Angels: In-Network Support for Minimum Distribution Time in P2P Overlays

    This paper proposes the use of in-network caches (which the authors call Angels) to reduce the Minimum Distribution Time (MDT) of a file from a seeder - a node that possesses the file - to a set of leechers - nodes who are interested in downloading the file. An Angel...

    Provided By Boston University

  • White Papers // Aug 2009

    Principles of Safe Policy Routing Dynamics

    This paper introduces the Dynamic Policy Routing (DPR) model that captures the propagation of route updates under arbitrary changes in topology or path preferences. DPR introduces the notion of causation chains where the route flap at one node causes a flap at the next node along the chain. Using DPR,...

    Provided By Boston University

  • White Papers // Jan 2011

    Authenticated Index Structures for Outsourced Databases

    In an Outsourced DataBase (ODB) system the database owner publishes data through a number of remote servers, with the goal of enabling clients at the edge of the network to access and query the data more efficiently. As servers might be untrusted or can be compromised, query authentication becomes an...

    Provided By Boston University

  • White Papers // Aug 2010

    Reconstruction and Analysis of 3D Trajectories of Brazilian Free-Tailed Bats in Flight

    The Brazilian free-tailed bat, Tadarida brasiliensis, roosts in very large colonies, consisting of hundreds of thousands of individuals. Each night, bats emerge from their day roosts in dense columns in a highly coordinated manner. The authors recorded short segments of an emergence using three spatially-calibrated and temporally synchronized thermal infrared...

    Provided By Boston University

  • White Papers // Jul 2010

    HAIL: Hierarchical Adaptive Interface Layout

    The authors present a framework to adapt software to the needs of individuals with severe motion disabilities who use mouse substitution interfaces. Typically, users are required to adapt to the interfaces that they wish to use. They propose interfaces that change and adapt to the user and their individual abilities....

    Provided By Boston University

  • White Papers // Oct 2010

    Customizable Keyboard

    Customizable Keyboard is an on-screen keyboard designed to be flexible and expandable. Instead of giving the user a keyboard layout Customizable Keyboard allows the user to create a layout that is accommodating to the user's needs. Customizable Keyboard also allows the user to select from a variety of ways to...

    Provided By Boston University

  • White Papers // Mar 2011

    Camera Canvas: Image Editing Software for People With Disabilities

    The authors developed Camera Canvas, photo editing and picture drawing software for individuals who cannot use their hands to operate a computer mouse. Camera Canvas is designed for use with camera-based mouse-replacement interfaces that allow a user with severe motion impairments to control the mouse pointer by moving his or...

    Provided By Boston University

  • White Papers // Mar 2011

    Adaptive Mouse-Replacement Interface Control Functions for Users With Disabilities

    The authors discuss the experiences employing a video-based mouse-replacement interface system, called the Camera Mouse, at various care facilities for individuals with severe motion impairments and propose adaptations of the system. People with severe motor disabilities face many challenges with assistive technology. Traditional approaches to assistive technology are often inflexible,...

    Provided By Boston University

  • White Papers // Mar 2011

    Menu Controller: Making Existing Software More Accessible for People With Motor Impairments

    Menu Controller was developed to make existing software more accessible for people with severe motor impairments, especially individuals who use mouse-replacement input systems. Windows applications have menus that are difficult to access by users with limited muscle control, due to the size and placement of the menu entries. The goal...

    Provided By Boston University

  • White Papers // Jul 2010

    Camera-Based Interfaces and Assistive Software for People With Severe Motion Impairments

    Intelligent assistive technology can greatly improve the daily lives of people with severe paralysis, who have limited communication abilities. People with motion impairments often prefer camera-based communication interfaces, because these are customizable, comfortable, and do not require user-borne accessories that could draw attention to their disability. The authors present an...

    Provided By Boston University

  • White Papers // Feb 2009

    Movement and Recovery Analysis of a Mouse-Replacement Interface for Users With Severe Disabilities

    The Camera Mouse is a mouse-replacement interface for users with movement impairments. It tracks a selected body feature, such as the nose, eyebrow or finger, through a web camera and translates the user's movements to movements of the mouse pointer. Occasionally, the Camera Mouse loses the feature being tracked, when...

    Provided By Boston University

  • White Papers // May 2009

    RefLink: An Interface That Enables People With Motion Impairments to Analyze Web Content and Dynamically Link to References

    In this paper, the authors present RefLink, an interface that allows users to analyze the content of web page by dynamically linking to an online encyclopedia such as Wikipedia. Upon opening a webpage, RefLink instantly provides a list of terms extracted from the webpage and annotates each term by the...

    Provided By Boston University

  • White Papers // Jul 2010

    Towards a Multi-Camera Mouse-Replacement Interface

    The authors present the efforts towards a multi-camera mouse-replacement system for computer users with severe motion impairments. They have worked with individuals with cerebral palsy or multiple sclerosis who use a publicly available interface that tracks the user's head movements with a single video camera and translates them into mouse...

    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 // 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 // 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 // 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 // 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 // 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 // Dec 2008

    Influence Of Corruption On Economic Growth Rate And Foreign Investments

    In order to investigate whether government regulations against corruption can affect the economic growth of a country, the authors analyze the dependence between Gross Domestic Product (GDP) per capita growth rates and changes in the Corruption Perceptions Index (CPI). For the period 1999-2004 on average for all countries in the...

    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 // 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 // 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 // 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 // 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 // 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 // Nov 2008

    Tracking Multiple Targets Using Binary Decisions from Wireless Sensor Networks

    This paper introduces a framework for tracking multiple targets over time using binary decisions collected by a wireless sensor network, and applies the methodology to two case studies - an experiment involving tracking people and a project tracking zebras. The tracking approach is based on a penalized maximum likelihood framework,...

    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 // 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 // Jan 2011

    Characterizing and Exploiting Reference Locality in Data Stream Applications

    In this paper, the authors investigate a new approach to process queries in data stream applications. They show that reference locality characteristics of data streams could be exploited in the design of superior and flexible data stream query processing techniques. They identify two different causes of reference locality: popularity over...

    Provided By Boston University

  • White Papers // Sep 2010

    Trade & Cap: A Customer-Managed, Market-Based System for Trading Bandwidth Allowances at a Shared Link

    This paper proposes Trade & Cap (T&C), an economics-inspired mechanism that incentivizes users to voluntarily coordinate their consumption of the bandwidth of a shared network link so as to converge on what they perceive to be an equitable allocation, while ensuring efficient resource utilization. Under T&C, rather than acting as...

    Provided By Boston University

  • White Papers // Jan 2011

    Programming With Dependently Typed Data Structures

    The mechanism for declaring datatypes in functional programming languages such as ML and Haskell is of great use in practice. This mechanism, however, often suffers from its imprecision in capturing various invariants inherent in data structures. The introduction of dependent datatypes in Dependent ML (DML) can partly remedy the situation,...

    Provided By Boston University

  • White Papers // Jan 2011

    Dependent Types for Program Termination Verification

    Program termination verification is a challenging research subject of significant practical importance. While there is already a rich body of literature on this subject, it is still undeniably a difficult task to design a termination checker for a realistic programming language that supports general recursion. In this paper, the authors...

    Provided By Boston University

  • White Papers // Jan 2011

    Dependent ML: An Approach to Practical Programming With Dependent Types

    The authors present an approach to enriching the type system of ML with a restricted form of dependent types, where type index terms are required to be drawn from a given type index language that is completely separate from run-time programs, leading to the DML language schema. This enrichment allows...

    Provided By Boston University

  • White Papers // Mar 2011

    A Token Based Approach to Distributed Computation in Sensor Networks

    The authors consider distributed algorithms for data aggregation and function computation in sensor networks. The algorithms perform pairwise computations along edges of an underlying communication graph. A token is associated with each sensor node, which acts as a transmission permit. Nodes with active tokens have transmission permits; they generate messages...

    Provided By Boston University