University of Massachusetts

Displaying 1-40 of 178 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

    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 // 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 // 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

    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 // 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 // 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

    On the Benefits of Random Linear Coding for Unicast Applications in Disruption Tolerant Networks

    In this paper, the authors investigate the benefits of using a form of network coding known as Random Linear Coding (RLC) for unicast communications in a mobile Disruption Tolerant Network (DTN) under epidemic routing. Under RLC, DTN nodes store and then forward random linear combinations of packets as they encounter...

    Provided By University of Massachusetts

  • White Papers // Oct 2010

    On Bit Error Rate Performance of Polar Codes in Finite Regime

    Polar codes have been recently proposed as the first low complexity class of codes that can provably achieve the capacity of symmetric binary-input memoryless channels. Here, the authors study the bit error rate performance of finite-length polar codes under Belief Propagation (BP) decoding. They analyze the stopping sets of polar...

    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 // Apr 2009

    Using Randomized Caches in Probabilistic Real-Time Systems

    While hardware caches are generally effective at improving application performance, they greatly complicate performance prediction. Slight changes in memory layout or data access patterns can lead to large and systematic increases in cache misses, degrading performance. In the worst case, these misses can effectively render the cache useless. These pathological...

    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

    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 // Dec 2008

    Matilda: A Generic and Customizable Framework for Direct Model Execution in Model-Driven Software Development

    Traditional Model Driven Development (MDD) frameworks have three critical issues: abstraction gap between modeling and programming layers, a lack of traceability between models and programs, and a lack of customizability to support various combinations of modeling technologies and implementation/deployment technologies. In order to address these issues, this paper proposes a...

    Provided By University of Massachusetts

  • White Papers // Nov 2008

    iNetLab: A Model-Driven Development and Performance Engineering Environment for Autonomic Network Applications

    A key software engineering challenge in autonomic computing is the complexity of administrating operational policies of applications. In order to address this challenge, this paper proposes and evaluates a new development environment, called iNetLab, which is designed to improve the productivity of designing, maintaining and tuning operational policies in autonomic...

    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 // 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 // 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 // May 2009

    Separation of Sensor Control and Data in Closed-Loop Sensor Networks

    Sensor networks are prone to congestion due to bursty and high-bandwidth data traffic, combined with wireless links and many-to-one data routing to a sink. Delayed and dropped packets then degrade the performance of the sensing application. In this paper, the authors investigate the value of separate handling of sensor control...

    Provided By University of Massachusetts

  • White Papers // Jul 2009

    Evaluating the Control Overhead of Routing Protocols in Dynamic Ad Hoc Networks

    Wireless and Mobile Ad-hoc NETworks (MANETs) are distinguished by time-varying link characteristics and network topology. In such dynamic environments, the network must accommodate these changes, providing end-end packet delivery while at the same time incurring low control overhead. Yet this ideal is difficult to meet in practice: end-end delivery requires...

    Provided By University of Massachusetts

  • White Papers // Jun 2010

    Publish/Subscribe Techniques for P2P Networks

    As P2P is a popular networking paradigm in today's Internet, many research and development efforts are geared toward services that can be useful to the users of P2P networks. This paper is focused particularly on publish/subscribe services and discusses recent techniques that enable these services in P2P networks. The publish/subscribe...

    Provided By University of Massachusetts

  • White Papers // Oct 2008

    Machine Learning Based Localization

    A vast majority of localization techniques proposed for sensor networks are based on triangulation methods in Euclidean geometry. They utilize the geometrical properties of the sensor network to infer the sensor locations. A fundamentally different approach is presented in this chapter. This approach is based on machine learning, in which...

    Provided By University of Massachusetts

  • White Papers // Jul 2010

    Spatial Reuse in Underwater Acoustic Networks Using RTS/CTS MAC Protocols

    Using analytic models and simulation results, the authors examine spatial reuse and the effectiveness of RTS/CTS MAC protocols in underwater acoustic networks. They are not looking at the question of network throughput, which is affected mostly by propagation delay, but rather the protocol's ability to prevent collisions. RTS/CTS-based collision-avoidance protocols...

    Provided By University of Massachusetts

  • White Papers // Aug 2009

    On the Mitigation of Traffic Correlation Attacks on Router Queues

    Traffic burstiness is known to be undesirable for a router as it increases the router's queue length and hence the queueing delays of data flows. This poses a security problem in which an attacker intentionally introduces traffic burstiness into routers. The authors consider a correlation attack, whose fundamental characteristic is...

    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 // 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 // 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 2009

    Trojan Side-Channels: Lightweight Hardware Trojans Through Side-Channel Engineering

    The general trend in semiconductor industry to separate design from fabrication leads to potential threats from untrusted integrated circuit foundries. In particular, malicious hardware components can be covertly inserted at the foundry to implement hidden back-doors for unauthorized exposure of secret information. This paper proposes a new class of hardware...

    Provided By University of Massachusetts

  • White Papers // Jun 2009

    Strictly Declarative Specification of Sophisticated Points-To Analyses

    The authors present the Doop framework for points-to analysis of Java programs. Doop builds on the idea of specifying pointer analysis algorithms declaratively, using Datalog: a logic-based language for defining (recursive) relations. They carry the declarative approach further than past work by describing the full end-to-end analysis in Datalog and...

    Provided By University of Massachusetts

  • White Papers // Feb 2010

    Leveraging Multi-Radio Communication for Mobile Wireless Sensor Networks

    An important challenge in mobile sensor networks is to enable energy-efficient communication over a diversity of distances while being robust to wireless effects caused by node mobility. In this paper, the authors argue that the pairing of two complementary radios with heterogeneous range characteristics enables greater range and interference diversity...

    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

    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 // Jun 2010

    Performance Modeling of HS-RR-TCP Over Load-Balanced Optical Burst-Switched (OBS) Networks

    TCP-over-OBS is a promising transport paradigm to support next-generation Internet. It is well-known that load-balanced routing generally improves loss performance over OBS. The authors identify that implementing TCP over load-balanced OBS could lead to persistent out-of-order delivery of TCP segments, resulting in unnecessary timeouts and fast retransmissions. In this paper...

    Provided By University of Massachusetts

  • White Papers // Jul 2010

    Multi-Layer Loss Recovery in TCP Over Optical Burst-Switched (OBS) Networks

    It is well-known that the bufferless nature of OBS networks causes random burst loss even at low traffic loads. When TCP is used over OBS, these random losses make the TCP sender decrease its congestion window even though the network may not be congested. This results in significant TCP throughput...

    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 // Sep 2010

    Load-Aware Anycast Routing in IP-Over-WDM Networks

    In this paper, the authors propose anycast routing methods to improve the performance of reconfigurable WDM networks under the variations in the IP traffic. They first investigate anycast communication via Impairment-Aware Anycast Routing (IAAR); their simulation results show significant improvement in the blocking probability. They also investigate the proposed Load-Aware...

    Provided By University of Massachusetts

  • White Papers // Nov 2010

    Dynamic Circuits With Lightpath Switching OverWavelength Routed Networks

    In this paper, the authors examine provisioning holding-time-aware dynamic circuits using a technique called Light-Path Switching (LPS). Instead of using the same lightpath for the duration of the data transmission, in LPS they allow a request to switch lightpaths over time. Data transmission may begin on one lightpath from the...

    Provided By University of Massachusetts

  • White Papers // Sep 2009

    Coordinated Multi-Layer Loss Recovery in TCP Over Optical Burst-Switched (OBS) Networks

    It is well-known that the bufferless nature of OBS networks causes random burst loss even at low traffic loads. When TCP is used over OBS, these random losses make the TCP sender decrease its congestion window even though the network may not be congested. This results in significant TCP throughput...

    Provided By University of Massachusetts

  • White Papers // Sep 2009

    Tabu Search Meta-Heuristic for Static Manycast Routing And Wavelength Assignment Over Wavelength-Routed Optical WDM Networks

    This paper presents a tabu search meta-heuristic to solve the static MAnycast Routing and Wavelength Assignment problem (MA-RWA). The problem is to route a set of static manycast requests over a wavelength-routed WDM network such that the number of wavelengths required is minimized. The authors present the details of a...

    Provided By University of Massachusetts

  • White Papers // Nov 2009

    Static Manycast Routing and Wavelength Assignment Over Wavelength-Routed Optical WDM Networks

    The authors present their initial work for static MAnycast Routing and Wavelength Assignment (MA-RWA) over wavelength-routed optical WDM networks. The goal is to route a set of static manycast requests over a wavelength-routed WDM network while minimizing the number of wavelengths required. This is the first time the problem has...

    Provided By University of Massachusetts

  • White Papers // Nov 2009

    Unfairness in TCP Performance Over Lossy Optical Burst-Switched (OBS) Networks

    One of TCP's primary objectives is to provide fairness to all flows competing for resources in a network. Since the popular flavors of TCP were designed to work with electronic packet-switched networks, they behave differently when used over Optical Burst-Switched networks (OBS). In OBS, burst loss occurs due to random...

    Provided By University of Massachusetts

  • White Papers // Nov 2010

    Precisely Serializable Snapshot Isolation (PSSI)

    Many popular database management systems provide Snapshot Isolation (SI) for concurrency control, either in addition to or in place of full serializability based on locking. Snapshot isolation was introduced in 1995, with noted anomalies that can lead to serializability violations. Full serializability was provided in 2008 and improved in 2009...

    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 // Dec 2008

    On the Performance of Random Linear Network Coding in Relay Networks

    The authors compare the reliability performance gain of Random Linear Network Coding (RLNC) with Automatic Repeat ReQuest (ARQ) for a wireless relay network taking into account overhead and complexity of feedback mechanism as well as overhead due to encoding vector embedded in packet header under RLNC. The authors' goal is...

    Provided By University of Massachusetts

  • White Papers // Feb 2009

    Autonomic and Coevolutionary Sensor Networking With BiSNET/e

    Wireless Sensor Networks (WSNs) applications are often required to balance the tradeoffs among conflicting operational objectives (e.g., latency and power consumption) and operate at an optimal tradeoff. This chapter proposes and evaluates a Biologically-inspired architecture, called BiSNET/e, which allows WSN applications to overcome this issue. BiSNET/e is designed to support...

    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 // Aug 2010

    Multi-Target Tracking Using Proximity Sensors

    The authors consider the problem of tracking multiple moving targets in a continuous field using proximity sensors, which are binary sensors that can sense target presence by performing local energy detection subject to noise. Compared with more sophisticated sensors, proximity sensors have the advantage of having lower costs and lower...

    Provided By University of Massachusetts