University of Massachusetts

Displaying 1-40 of 147 results

  • White Papers // Feb 2013

    Yank: Enabling Green Data Centers to Pull the Plug

    Balancing a data center's reliability, cost, and carbon emissions is challenging. For instance, data centers designed for high availability require a continuous flow of power to keep servers powered on, and must limit their use of clean, but intermittent, renewable energy sources. In this paper, the authors present Yank, which...

    Provided By University of Massachusetts

  • White Papers // Dec 2012

    Compiling Relational Database Schemata Into Probabilistic Graphical Models

    A majority of scientific and commercial data is stored in relational databases. Probabilistic models over such datasets would allow probabilistic queries, error checking, and inference of missing values, but to this day machine learning expertise is required to construct accurate models. Fortunately, current probabilistic programming tools ease the task of...

    Provided By University of Massachusetts

  • White Papers // Oct 2012

    Everlasting Secrecy by Exploiting Non-Idealities of the Eavesdropper's Receiver

    Secure communication over a memoryless wiretap channel in the presence of a passive eavesdropper is considered. Traditional information-theoretic security methods require an advantage for the main channel over the eavesdropper channel to achieve a positive secrecy rate, which in general cannot be guaranteed in wireless systems. Here, the authors exploit...

    Provided By University of Massachusetts

  • White Papers // Aug 2012

    CloudCast: Cloud Computing for Short-term Mobile Weather Forecasts

    Since today's weather forecasts only cover large regions every few hours, their use in severe weather is limited. In this paper, the authors present CloudCast, an application that provides short-term weather forecasts depending on user's current location. Since severe weather is rare, CloudCast leverages pay-as-you-go cloud platforms to eliminate dedicated...

    Provided By University of Massachusetts

  • White Papers // Jun 2012

    Designing Privacy-Preserving Smart Meters with Low-Cost Microcontrollers

    Smart meters that track ne-grained electricity usage and implement sophisticated usage-based billing policies, e.g., based on time-of-use, are a key component of recent smart grid initiatives that aim to increase the electric grid's efficiency. A key impediment to widespread smart meter deployment is that ne-grained usage data indirectly reveals detailed...

    Provided By University of Massachusetts

  • White Papers // May 2012

    An Empirical Study of Memory Sharing in Virtual Machines

    Content-based page sharing is a technique often used in virtualized environments to reduce server memory requirements. Many systems have been proposed to capture the benefits of page sharing. However, there have been few analyses of page sharing in general, both considering its real-world utility and typical sources of sharing potential....

    Provided By University of Massachusetts

  • White Papers // Mar 2012

    ETransform: Transforming Enterprise Data Centers by Automated Consolidation

    Modern day enterprises have a large IT infrastructure comprising thousands of applications running on servers housed in tens of data centers geographically spread out. These enterprises periodically perform a transformation of their entire IT infrastructure to simplify, decrease operational costs and enable easier management. However, the large number of different...

    Provided By University of Massachusetts

  • White Papers // Jan 2012

    SmartCap: Flattening Peak Electricity Demand in Smart Homes

    Flattening household electricity demand reduces generation costs, since costs are disproportionately affected by peak demands. While the vast majority of household electrical loads are interactive and have little scheduling flexibility (TVs, microwaves, etc.), a substantial fraction of home energy use derives from background loads with some, albeit limited, flexibility. Examples...

    Provided By University of Massachusetts

  • White Papers // Jan 2012

    Providing End-to-End Secure Communications in Wireless Sensor Networks

    In many Wireless Sensor Networks (WSNs), providing end to end secure communications between sensors and the sink is important for secure network management. While there have been many works devoted to hop by hop secure communications, the issue of end to end secure communications is largely ignored. In this paper,...

    Provided By University of Massachusetts

  • White Papers // Jan 2012

    Physical Layer Security From Inter-Session Interference in Large Wireless Networks

    Physical layer secrecy in wireless networks in the presence of eavesdroppers of unknown location is considered. In contrast to prior schemes, which have expended energy in the form of cooperative jamming to enable secrecy, the authors develop schemes where multiple transmitters send their signals in a cooperative fashion to confuse...

    Provided By University of Massachusetts

  • White Papers // Jan 2012

    Energy-Aware Load Balancing in Content Delivery Networks

    Internet-scale distributed systems such as Content Delivery Networks (CDNs) operate hundreds of thousands of servers deployed in thousands of data center locations around the globe. Since, the energy costs of operating such a large IT infrastructure are a significant fraction of the total operating costs, the authors argue for redesigning...

    Provided By University of Massachusetts

  • White Papers // Jan 2012

    Formal Analysis of Passive Measurement Inference Techniques

    Verifying the accuracy of a passive measurements-based inference technique under all possible network scenarios is a difficult challenge - the measurement point has limited observability of events along the path, and monitored paths can exhibit a wide range of network properties (packet loss, reordering, end-end delay, route changes). In this...

    Provided By University of Massachusetts

  • White Papers // Jan 2012

    An Effective Architecture and Algorithm for Detecting Worms With Various Scan Techniques

    Since the days of the Morris worm, the spread of malicious code has been the most imminent menace to the Internet. Worms use various scanning methods to spread rapidly. Worms that select scan destinations carefully can cause more damage than worms employing random scan. This paper analyzes various scan techniques....

    Provided By University of Massachusetts

  • White Papers // Jan 2012

    Achievable Rates of Physical Layer Network Coding Schemes on the Exchange Channel

    Network coding, where relay nodes combine the information received from multiple flows rather than simply replicating and forwarding the received packets, has shown the promise of significantly improving system performance. In very recent work, researchers have presented methods for increasing system throughput by employing methods inspired by network coding to...

    Provided By University of Massachusetts

  • White Papers // Sep 2011

    Evaluation of the Universal Geocast Scheme for VANETs

    Recently, a number of communications schemes have been proposed for Vehicular Ad hoc NETworks (VANETs). A promising approach, the Universal Geocast Scheme (UGS), provides for a diverse variety of VANET-specific characteristics such as time-varying topology, protocol variation based on road congestion, and support for non line-of-sight communication. In this paper,...

    Provided By University of Massachusetts

  • White Papers // Sep 2011

    Analytical Design of Inter-Vehicular Communications for Collision Avoidance

    The authors address the analytical design of a communications system that seeks to provide timely safety information for drivers who are unaware of an imminent collision. They develop a model to characterize the delay requirements needed to prevent such collisions. By simultaneously addressing the multiuser interference and propagation effects such...

    Provided By University of Massachusetts

  • White Papers // Sep 2011

    Predico: A System for What-If Analysis in Complex Data Center Applications

    Modern data center applications are complex distributed systems with tens or hundreds of interacting software components. An important management task in data centers is to predict the impact of a certain workload or reconfiguration change on the performance of the application. Such predictions require the design of "What-if" models of...

    Provided By University of Massachusetts

  • White Papers // Jul 2011

    On Managing Quality of Experience of Multiple Video Streams in Wireless Networks

    Managing the Quality-of-Experience (QoE) of video streaming for wireless clients is becoming increasingly important due to the rapid growth of video traffic on wireless networks. The inherent variability of the wireless channel as well as the Variable Bit Rate (VBR) of the compressed video streams make managing the QoE a...

    Provided By University of Massachusetts

  • White Papers // Jun 2011

    Exploring the Feasibility of Low Cost Fault Injection Attacks on Sub-Threshold Devices Through an Example of a 65nm AES Implementation

    The continuous scaling of VLSI technology and the aggressive use of low power strategies (such as sub-threshold voltage) make it possible to implement standard cryptographic primitives within the very limited circuit and power budget of RFID devices. On the other hand, such cryptographic implementations raise concerns regarding their vulnerability to...

    Provided By University of Massachusetts

  • White Papers // Jun 2011

    Forensic Triage for Mobile Phones With DEC0DE

    The authors present DEC0DE, a system for recovering information from phones with unknown storage formats, a critical problem for forensic triage. Because phones have myriad custom hardware and software, they examine only the stored data. Via flexible descriptions of typical data structures, and using a classic dynamic programming algorithm, they...

    Provided By University of Massachusetts

  • White Papers // Jun 2011

    iMapReduce: A Distributed Computing Framework for Iterative Computation

    Relational data are pervasive in many applications such as data mining or social network analysis. These relational data are typically massive containing at least millions or hundreds of millions of relations. This poses demand for the design of distributed computing frameworks for processing these data on a large cluster. MapReduce...

    Provided By University of Massachusetts

  • White Papers // Jun 2011

    Financialization, Household Credit And Economic Slowdown In The U.S.

    Three important features of the U.S. economy during the neoliberal era since the mid-1970s have been: growing financialization, increasing household debt, and stagnant real wages for production and nonsupervisory workers. This paper develops a discrete-time Marxian circuit of capital model to analyze the links between these three features and economic...

    Provided By University of Massachusetts

  • White Papers // May 2011

    Entropy Extraction in Metastability-Based TRNG

    True Random Number Generators (TRNG) implemented in Deep Sub Micron (DSM) technologies become biased in bit generation due to process variations and fluctuations in operating conditions. A variety of mechanisms ranging from analog and digital circuit techniques to algorithmic post-processing can be employed to remove bias. In this paper, the...

    Provided By University of Massachusetts

  • White Papers // May 2011

    Empirical Analysis of the Evolution of Follower Network: A Case Study on Douban

    Follower networks such as Twitter and Digg are becoming popular form of social information networks. This paper seeks to gain insights into how they evolve and the relationship between their structure and their ability to spread information. By studying the Douban follower network, which is a popular online social network...

    Provided By University of Massachusetts

  • White Papers // May 2011

    BenchLab: An Open Testbed for Realistic Benchmarking of Web Applications

    Web applications have evolved from serving static content to dynamically generating Web pages. Web 2.0 applications include JavaScript and AJAX technologies that manage increasingly complex interactions between the client and the Web server. Traditional benchmarks rely on browser emulators that mimic the basic network functionality of real Web browsers but...

    Provided By University of Massachusetts

  • White Papers // Apr 2011

    A Hybrid Self-Calibration Technique to Mitigate the Effect of Variability in TRNG

    In this paper, the authors briefly study the effect of variability in process and operating conditions on the statistics and performance of on-chip True Random Number Generator (TRNG), using the cryptographic measure of bit entropy. Circuits designed in deep submicron technologies are susceptible to variation in process. The variability may...

    Provided By University of Massachusetts

  • White Papers // Apr 2011

    A New Virtual Indexing Method for Measuring Host Connection Degrees

    The authors present a new virtual indexing method for estimating host connection degrees for high-speed links. It is based on the virtual connection degree sketch where a compact sketch of network traffic is built by generating the associated virtual bitmaps for each host. Each virtual bitmap consists of a fixed...

    Provided By University of Massachusetts

  • White Papers // Mar 2011

    BenchLab: Benchmarking With Real Web Applications and Web Browsers

    Popular benchmarks such as TPC-W and RUBiS that are commonly used for evaluation by the systems community are no longer representative of modern Web applications. Many of these benchmarks lack the features such as JavaScript and AJAX that are essential to real Web 2.0 applications. Further, traditional benchmarks rely on...

    Provided By University of Massachusetts

  • White Papers // Mar 2011

    Finding a "Kneedle" in a Haystack: Detecting Knee Points in System Behavior

    Computer systems often reach a point at which the relative cost to increase some tunable parameter is no longer worth the corresponding performance benefit. These "Knees" typically represent beneficial points that system designers have long selected to best balance inherent trade-offs. While prior work largely uses ad hoc, system-specific approaches...

    Provided By University of Massachusetts

  • White Papers // Mar 2011

    E2R: Energy Efficient Routing for Multi-Hop Green Wireless Networks

    Wireless communication consumes a significant amount of energy in wireless networks. Most multi-hop wireless routing protocols are adopted from wired network routing protocols and use pre-selected single or multiple minimum cost paths to forward data packets. However, unlike wired networks, a wireless network has unique characteristics such as unreliable wireless...

    Provided By University of Massachusetts

  • White Papers // Mar 2011

    Dolly: Virtualization-Driven Database Provisioning for the Cloud

    Cloud computing platforms are becoming increasingly popular for e-commerce applications that can be scaled on-demand in a very cost effective way. Dynamic provisioning is used to autonomously add capacity in multi-tier cloud-based applications that see workload increases. While many solutions exist to provision tiers with little or no state in...

    Provided By University of Massachusetts

  • White Papers // Mar 2011

    TCP Over Optical Burst-Switched Networks With Controlled Burst Retransmission

    For Optical Burst-Switched (OBS) networks in which TCP is implemented at a higher layer, the loss of bursts can lead to serious degradation of TCP performance. Due to the bufferless nature of OBS, random burst losses may occur, even at low traffic loads. Consequently, these random burst losses may be...

    Provided By University of Massachusetts

  • White Papers // Mar 2011

    Improving TCP Performance Over Optical Burst-Switched (OBS) Networks Using Forward Segment Redundancy

    Random contentions occur in Optical Burst-Switched (OBS) networks because of one-way signaling and lack of optical buffers. These contentions can occur at low loads and are not necessarily an indication of congestion. The loss caused by them, however, causes TCP at the transport layer to reduce its send rate drastically,...

    Provided By University of Massachusetts

  • White Papers // Mar 2011

    Employer-Provided Health Insurance And Labor Supply Of Married Women

    This paper presents new evidence on the effect of husbands' health insurance on wives' labor supply. Previous cross-sectional studies have estimated a significant negative effect of spousal coverage on wives' labor supply. However, these estimates potentially suffer from bias due to the simultaneity of wives' labor supply and the health...

    Provided By University of Massachusetts

  • White Papers // Feb 2011

    Defending Against XML-Based Attacks Using State-Based XML Firewall

    With the proliferation of service-oriented systems and cloud computing, web services security has gained much attention in recent years. Web service attacks, called XML-based attacks, typically occur at the SOAP message level, thus they are not readily handled by existing security mechanisms such as a conventional firewall. In order to...

    Provided By University of Massachusetts

  • White Papers // Feb 2011

    Dynamic Anycast Routing and Wavelength Assignment in WDM Networks Using Ant Colony Optimization (ACO)

    Ant Colony Optimization (ACO) is a probabilistic technique used for solving complex computational problems, such as finding optimal routes in networks. It has been proved to perform better than simulated annealing and genetic algorithm approaches for solving dynamic problems. ACO algorithms can quickly adapt to real-time changes in the system....

    Provided By University of Massachusetts

  • White Papers // Feb 2011

    Employment Effects Under Planned Changes To The EPA's Air Pollution Rules

    The U.S. electric power sector is changing and modernizing in response to societal and market forces. Power companies face a business imperative to meet increasing pressures for cleaner, more efficient energy that will safeguard public health and protect the world's climate. These forces are already transforming the industry. Significant capital...

    Provided By University of Massachusetts

  • White Papers // Feb 2011

    Identifying Mobiles Hiding Behind Wireless Routers

    The Network Address Translation technique (NAT) is widely used in wireless routers. It is a low cost solution to IPv4 address space limitations. However, cyber criminals may abuse NAT and hide behind wireless routers to use mobile devices and conduct crimes. To identify a suspect mobile device, the authors should...

    Provided By University of Massachusetts

  • White Papers // Jan 2011

    Robust Multipath Routing in Large Wireless Networks

    One of the challenges of wireless networks is to provide a reliable end-to-end path between two end hosts in the face of link and node outages. These can occur due to fluctuations in channel quality, node movement, or node failure. One mechanism that has been proposed is based on multipath...

    Provided By University of Massachusetts

  • White Papers // Jan 2011

    Dynamic Cache Reconfiguration Strategies for a Cluster-Based Streaming Proxy

    The high bandwidth and the relatively longlived characteristics of digital video are key limiting factors in the wide-spread usage of streaming content over the Internet. The problem is further complicated by the fact that the video popularity changes over time. This paper studies caching issues for a cluster-based streaming proxy...

    Provided By University of Massachusetts

  • White Papers // Dec 2010

    Exploiting Half-Wits: Smarter Storage for Low-Power Devices

    This work analyzes the stochastic behavior of writing to embedded flash memory at voltages lower than recommended by a microcontroller's specifications to reduce energy consumption. Flash memory integrated within a microcontroller typically requires the entire chip to operate on common supply voltage almost double what the CPU portion requires. The...

    Provided By University of Massachusetts

  • White Papers // Oct 2009

    Replication Routing in DTNs: A Resource Allocation Approach

    Routing protocols for Disruption-Tolerant Networks (DTNs) use a variety of mechanisms, including discovering the meeting probabilities among nodes, packet replication, and network coding. The primary focus of these mechanisms is to increase the likelihood of finding a path with limited information, and so these approaches have only an incidental effect...

    Provided By University of Massachusetts

  • White Papers // Aug 2008

    MAP: A Scalable Monitoring System for Dependable 802.11 Wireless Networks

    As individuals and enterprises increasingly depend on 802.11 wireless LANs for mission-critical applications, in particular time-sensitive applications such as voice and video, the need to detect malicious attacks and protect legitimate users becomes even more important. Detecting 802.11 attacks, however, requires measurement at the Media Access Control (MAC) layer, which...

    Provided By University of Massachusetts

  • White Papers // Oct 2009

    How The Campaign Finance System Affected Party Organizations In The 2008 Elections

    This paper explores changes and continuities in how parties organized themselves in the 2008 elections through the lens of party financing. Two questions motivate this analysis. First, how do changes in campaign finance laws affect political parties? In this study the author observes changes wrought by the Bipartisan Campaign Reform...

    Provided By University of Massachusetts

  • White Papers // Jan 2011

    Dynamic Cache Reconfiguration Strategies for a Cluster-Based Streaming Proxy

    The high bandwidth and the relatively longlived characteristics of digital video are key limiting factors in the wide-spread usage of streaming content over the Internet. The problem is further complicated by the fact that the video popularity changes over time. This paper studies caching issues for a cluster-based streaming proxy...

    Provided By University of Massachusetts

  • White Papers // Jan 2011

    A Comparison of Sender-Initiated and Receiver-Initiated Reliable Multicast Protocols

    Sender-initiated reliable multicast protocols based on the use of positive Acknowledgments (ACKs) can suffer performance degradation as the number of receivers increases. This degradation is due to the fact that the sender must bear much of the complexity associated with reliable data transfer (e.g., maintaining state information and timers for...

    Provided By University of Massachusetts

  • White Papers // Jan 2011

    Pre-Analyzed Resource and Time Provisioning in Distributed Real-Time Systems: An Application to Mobile Robotics

    The work is motivated by mobile robotic applications where a team of autonomous robots cooperate in achieving a goal, e.g., using sensor feeds to locate trapped humans in a building on fire. To attain the goal, kinematic Line-Of-Sight (LOS) constraints must be enforced to build interference free communication paths, and...

    Provided By University of Massachusetts

  • White Papers // Jan 2011

    Effectiveness of Dynamic Resource Allocation for Handling Internet Flash Crowds

    Internet data centers host multiple Web applications on shared hardware resources. These data centers are typically provisioned to meet the expected peak demands of the hosted applications based on normal time-of-day effects. Such an over-provisioning approach is not robust to flash crowd scenarios, where the load increase of some hosted...

    Provided By University of Massachusetts

  • White Papers // Jan 2011

    Resource Overbooking and Application Profiling in Shared Hosting Platforms

    In this paper, the authors present techniques for provisioning CPU and network resources in shared hosting platforms running potentially antagonistic third-party applications. The primary contribution of the work is to demonstrate the feasibility and benefits of overbooking resources in shared platforms. Since an accurate estimate of an application's resource needs...

    Provided By University of Massachusetts

  • White Papers // Jan 2011

    An Online Optimization-Based Technique for Dynamic Resource Allocation in GPS Servers

    Since web workloads are known to vary dynamically with time, in this paper, the authors argue that dynamic resource allocation techniques are necessary in the presence of such workloads to provide guarantees to web applications running on shared data centers. To address this issue, they present an analytic model of...

    Provided By University of Massachusetts

  • White Papers // Jan 2011

    Evaluation of Object Placement Techniques in a Policy-Managed Storage System

    Storage management cost is a significant fraction of the total cost of ownership of large, enterprise storage systems. Consequently, software automation of common storage management tasks so as to reduce the total cost of ownership is an active area of research. In this paper, the authors consider a policy-managed storage...

    Provided By University of Massachusetts

  • White Papers // Jan 2011

    Dynamic Provisioning of Multi-Tier Internet Applications

    Dynamic capacity provisioning is a useful technique for handling the multi-time-scale variations seen in Internet workloads. In this paper, the authors propose a novel dynamic provisioning technique for multi-tier Internet applications that employs a flexible queuing model to determine how much resources to allocate to each tier of the application,...

    Provided By University of Massachusetts

  • White Papers // Jun 2010

    Exploiting the Interplay Between Memory and Flash Storage in Embedded Sensor Devices

    Although memory is an important constraint in embedded sensor nodes, existing embedded applications and systems are typically designed to work under the memory constraints of a single platform and do not consider the interplay between memory and flash storage. In this paper, the authors present the design of a memory-adaptive...

    Provided By University of Massachusetts

  • White Papers // Jan 2011

    Scalable Techniques for Memory-efficient CDN Simulations

    Since CDN simulations are known to be highly memory-intensive, in this paper, the authors argue the need for reducing the memory requirements of such simulations. They propose a novel memory-efficient data structure that stores cache state for a small subset of popular objects accurately and uses approximations for storing the...

    Provided By University of Massachusetts

  • White Papers // Jan 2011

    Proxy-Assisted Power-Friendly Streaming to Mobile Devices

    Since multimedia applications are known to be resource-hungry and mobile devices are resource-poor, in this paper, the authors propose techniques to reduce the energy consumption of streaming media applications running on mobile hosts. The proposed techniques are proxy-based and involve power-friendly transformations on the requested streams so as to limit...

    Provided By University of Massachusetts

  • White Papers // Jan 2011

    Impact of Space-Time Multiplexing Granularity on Provisioning in On-Demand Data Centers: Opportunities and Challenges

    On-demand data centers efficiently host multiple applications on shared hardware by dynamically provisioning resources in response to workload variations. In this paper, the authors use real-world e-commerce workloads to demonstrate that the efficiency of such dynamic provisioning is critically dependent on the granularity of reallocation. Specifically, they show that the...

    Provided By University of Massachusetts

  • White Papers // Oct 2010

    TREC 2010 Web Track Notebook: Term Dependence, Spam Filtering and Quality Bias

    Many existing retrieval approaches treat all the documents in the collection equally, and do not take into account the content quality of the retrieved documents. In the submissions for TREC 2010 Web Track, the authors utilize quality-biased ranking methods that are aimed to promote documents that potentially contain high-quality content,...

    Provided By University of Massachusetts

  • White Papers // Dec 2009

    Dynamic Resource Scheduling in Disruption-Prone Software Development Environments

    Good resource scheduling plays a pivotal role in successful software development projects. However, effective resource scheduling is complicated by such disruptions as requirements changes, urgent bug fixing, incorrect or unexpected process execution, and staff turnover. Such disruptions demand immediate attention, but can also impact the stability of other ongoing projects....

    Provided By University of Massachusetts

  • White Papers // Jan 2010

    Secure Wireless Communication With Dynamic Secrets

    This paper introduces a set of low-complexity algorithms that when coupled with link layer retransmission mechanisms, strengthen wireless communication security. The basic idea is to generate a series of secrets from inevitable transmission errors and other random factors in wireless communications. Because these secrets are constantly extracted from the communication...

    Provided By University of Massachusetts

  • White Papers // Mar 2010

    Applying Software Engineering Technology to Support the Clear and Precise Specification of Scientific Processes

    With the availability of powerful computational and communication systems, scientists now readily access large, complicated derived datasets and build on those results to produce, through further processing, yet other derived datasets of interest to themselves and others. The scientific processes used to create such datasets must be clearly documented so...

    Provided By University of Massachusetts

  • White Papers // May 2010

    Physical-Layer-Enhanced Wireless Secret Key Exchange

    This paper addresses the problem of efficiently establishing a shared secret key over an open wireless channel in the presence of an active (Jamming) adversary. A commonly employed technique in practice for key sharing is the cryptographic elliptic-curve Diffie-Hellman (DH) protocol; however, its communication cost in a jammed environment is...

    Provided By University of Massachusetts

  • White Papers // Jan 2010

    A Relay Assisted Cooperative Transmission Protocol for Wireless Multiple Access Systems

    This paper proposes a spectrally efficient cooperative transmission protocol for multiple access scenarios. The key feature is to utilize multi-user diversity and fully exploit the dynamic nature of radio propagation. In particular, by carefully scheduling the multiple sources and relays' transmissions, a source with a poor connection to the destination...

    Provided By University of Massachusetts

  • White Papers // Dec 2010

    Efficient Algorithms for Neighbor Discovery in Wireless Networks

    Wireless ad hoc networks and sensor networks are typically deployed without any communication infrastructure and are required to "Configure" themselves upon deployment. For instance, immediately upon deployment, a node has no knowledge of other nodes in its transmission range and needs to discover its neighbors in order to communicate with...

    Provided By University of Massachusetts

  • White Papers // May 2010

    Multi-User Diversity for Secrecy in Wireless Networks

    The ability to transmit a message securely in the presence of eavesdroppers in a dense wireless network is considered. As with a number of recent schemes, system nodes other than the transmitter and receiver are chosen to generate noise that confuses the eavesdropper. By exploiting the dynamics of the fading,...

    Provided By University of Massachusetts

  • White Papers // Jan 2011

    Cloudy Computing: Leveraging Weather Forecasts in Energy Harvesting Sensor Systems

    To sustain perpetual operation, systems that harvest environmental energy must carefully regulate their usage to satisfy their demand. Regulating energy usage is challenging if a system's demands are not elastic and its hardware components are not energy-proportional, since it cannot precisely scale its usage to match its supply. Instead, the...

    Provided By University of Massachusetts

  • White Papers // Jan 2011

    Quantifying the Benefits of Resource Multiplexing in On-Demand Data Centers

    On-demand data centers host multiple applications on server farms by dynamically provisioning resources in response to workload variations. The efficiency of such dynamic provisioning on the required server farm capacity is dependent on several factors the granularity and frequency of reallocation, the number of applications being hosted, the amount of...

    Provided By University of Massachusetts

  • White Papers // Jan 2011

    Design Considerations for the Symphony Integrated Multimedia File System

    A multimedia file system supports diverse application classes that access data with heterogeneous characteristics. In this paper, the authors describe the experiences in the design and implementation of the Symphony multimedia file system. They first discuss various methodologies for designing multimedia file systems and examine their tradeoffs. They examine the...

    Provided By University of Massachusetts

  • White Papers // Feb 2010

    Towards a Virtualized Sensing Environment

    While deploying a sensor network is necessary for proof-of-concept experimentation, it is a time-consuming and tedious task that dramatically slows innovation. Treating sensor networks as shared testbeds and integrating them into a federated test bed infrastructure, such as FIRE, GENI, AKARI, or CNGI, enables a broad user community to benefit...

    Provided By University of Massachusetts

  • White Papers // Jan 2010

    JReq: Database Queries in Imperative Languages

    Instead of writing SQL queries directly, programmers often prefer writing all their code in a general purpose programming language like Java and having their programs be automatically rewritten to use database queries. Traditional tools such as object-relational mapping tools are able to automatically translate simple navigational queries written in object-oriented...

    Provided By University of Massachusetts

  • White Papers // Apr 2010

    Resource Management in Data-Intensive Clouds: Opportunities and Challenges

    Today's cloud computing platforms have seen much success in running compute-bound applications with time-varying or one-time needs. In this position paper, the authors will argue that the cloud paradigm is also well suited for handling data-intensive applications, characterized by the processing and storage of data produced by high-bandwidth sensors or...

    Provided By University of Massachusetts

  • White Papers // Jan 2011

    Cataclysm: Policing Extreme Overloads in Internet Services

    In this paper the authors present the Cataclysm server platform for handling extreme overloads in hosted Internet applications. The primary contribution of the work is to develop a comprehensive overload control approach that brings together admission control, dynamic provisioning of platform resources, and adaptive degradation of QoS. Cataclysm provides several...

    Provided By University of Massachusetts

  • White Papers // Jan 2011

    Design and Analysis of a Demand Adaptive and Locality Aware Streaming Media Server Cluster

    The wide availability of broadband networking technologies such as cable modems and DSL coupled with the growing popularity of the Internet has led to a dramatic increase in the availability and the use of online streaming media. With the "Last mile" network bandwidth no longer a constraint, the bottleneck for...

    Provided By University of Massachusetts

  • White Papers // Aug 2010

    Networked Cloud Orchestration: A GENI Perspective

    This paper describes the experience of developing a system for creation of distributed linked configurations of heterogeneous resources (slices) in GENI. The work leverages a number of unique architectural solutions (distributed architecture, declarative resource specifications, unique approach to slice instantiation) which is applicable to a wider set of problems related...

    Provided By University of Massachusetts

  • White Papers // Aug 2010

    Prioritizing Approaches To Economic Development In New England: Skills, Infrastructure, And Tax Incentives

    Along with the rest of the country, New England is beginning to pull out of the "Great Recession," but the recovery is expected to be slow and uneven. With hundreds of thousands of workers having lost their jobs, tens of thousands of families having lost their homes, and the prospect...

    Provided By University of Massachusetts

  • White Papers // Dec 2009

    The Potential Revenue From Financial Transactions Taxes

    The economic crisis of the last two years has led to serious concerns about the sharp growth in the federal government's fiscal deficit as well as the government's overall debt burden as a share of total U.S. GDP. Many analysts also believe that an excessive share of the economy's resources...

    Provided By University of Massachusetts

  • White Papers // Apr 2010

    Generating Jobs Through State Employer Tax Credits: Is There A Better Way?

    The Governors of Massachusetts, Connecticut, Rhode Island and several other states have recently proposed employer tax credits as measures to fight high unemployment in their states. Such policies have recently been passed at the federal level. The authors find that such policies, in fact, do little to increase aggregate demand,...

    Provided By University of Massachusetts

  • White Papers // Dec 2010

    Financial Stress And Asymmetric Financial Decisions

    Building wealth requires saving, borrowing, and investing. These decisions may depend on stress due to the lack of financial security (low financial assets). Stress should influence personal responses - emotional, behavioral, and cognitive - that in turn could determine financial decisions. The link between stress and financial decisions could be...

    Provided By University of Massachusetts

  • White Papers // Feb 2011

    Employment Effects Under Planned Changes To The EPA's Air Pollution Rules

    The U.S. electric power sector is changing and modernizing in response to societal and market forces. Power companies face a business imperative to meet increasing pressures for cleaner, more efficient energy that will safeguard public health and protect the world's climate. These forces are already transforming the industry. Significant capital...

    Provided By University of Massachusetts

  • White Papers // Aug 2010

    Have Differences In Credit Access Diminished In An Era Of Financial Market Deregulation?

    Over the past few decades, financial markets became increasingly deregulated and household debt expanded, sometimes rapidly. It is thus possible that greater deregulation led to improved credit access for typically underserved groups, such as minorities and low-income families, relative to their counterparts. Credit access is measured here by loan denials,...

    Provided By University of Massachusetts

  • White Papers // Jul 2010

    Boosting the Accuracy of Differentially Private Histograms Through Consistency

    The authors show that it is possible to significantly improve the accuracy of a general class of histogram queries while satisfying differential privacy. The approach carefully chooses a set of queries to evaluate, and then exploits consistency constraints that should hold over the noisy output. In a postprocessing phase, the...

    Provided By University of Massachusetts