UC Regents

Displaying 1-40 of 330 results

  • White Papers // Oct 2013

    Algebraic MACs and Keyed-Verification Anonymous Credentials

    The authors consider the problem of constructing anonymous credentials for use in a setting where the issuer of credentials is also the verifier, or more generally where the issuer and verifier have a shared key. In this setting they can use Message Authentication Codes (MACs) instead of public key signatures...

    Provided By UC Regents

  • White Papers // Oct 2013

    New Trapdoor Projection Maps for Composite-Order Bilinear Groups

    An asymmetric pairing over groups of composite order is a bilinear map e: G1 G2 - GT for groups G1 and G2 of composite order N = pq. The authors observe that a recent construction of pairing-friendly elliptic curves in this setting by the researcher exhibits surprising and unprecedented structure:...

    Provided By UC Regents

  • White Papers // Jun 2013

    Measuring the Practical Impact of DNSSEC Deployment

    DNSSEC extends DNS with a public-key infrastructure, providing compatible clients with cryptographic assurance for DNS records they obtain, even in the presence of an active network attacker. As with many internet protocol deployments, administrators deciding whether to deploy DNSSEC for their DNS zones must perform cost/benefit analysis. For some fraction...

    Provided By UC Regents

  • White Papers // Jun 2012

    Establishing Browser Security Guarantees through Formal Shim Verification

    Web browsers mediate access to valuable private data in domains ranging from health care to banking. Despite this critical role, attackers routinely exploit browser vulnerabilities to exfiltrate private data and take over the underlying system. The authors present QUARK, a browser whose kernel has been implemented and verified in Coq....

    Provided By UC Regents

  • White Papers // Aug 2011

    Improved Spectrum Access Control of Cognitive Radios Based on Primary ARQ Signals

    Cognitive radio systems capable of opportunistic spectrum access represent a new paradigm for improving the efficiency of current spectrum utilization. In this paper, the authors present a novel cognitive channel access method based on learning from both primary channel transmissions and the receiver ARQ feedback signals. This new sensing-plus-confirmation scheme...

    Provided By UC Regents

  • White Papers // Aug 2011

    Quality-of-Information Aware Networking for Tactical Military Networks

    In tactical military networks, decisions must often be made quickly based on information at hand. It is a challenge to provide decision makers with a notion of the quality of the information they have, or to provide a method by which decision makers can specify a required quality of information....

    Provided By UC Regents

  • White Papers // Aug 2011

    FERMI: A FEmtocell Resource Management System for Interference Mitigation in OFDMA Networks

    The demand for increased spectral efficiencies is driving the next generation broadband access networks towards deploying smaller cells (femtocells) and sophisticated air interface technologies (Orthogonal Frequency Division Multiple Access or OFDMA). The dense deployment of femtocells however, makes interference and hence resource management both critical and extremely challenging. In this...

    Provided By UC Regents

  • White Papers // Aug 2011

    LEISURE: A Framework for Load-Balanced Network-Wide Traffic Measurement

    Network-wide traffic measurement is of interest to network operators to uncover global network behavior for the management tasks of traffic accounting, debugging or troubleshooting, security, and traffic engineering. Increasingly, sophisticated network measurement tasks such as anomaly detection and security forensic analysis are requiring in-depth fine-grained flow-level measurements. However, performing in-depth...

    Provided By UC Regents

  • White Papers // Jul 2011

    On the Empirical Performance of Self-Calibrating WiFi Location Systems

    The pervasive deployment of 802.11 in modern enterprise buildings has long made it an attractive technology for constructing indoor location services. To this end, a broad range of algorithms have been proposed to accurately estimate location from 802.11 signal strength measurements, some without requiring manual calibration for each physical location....

    Provided By UC Regents

  • White Papers // Jul 2011

    Enhanching in Vehicle Digital Maps Via GPS Crowdsourcing

    In this paper, the authors propose a simple and effective method to extend digital maps with the location and timing of stop-signs and traffic lights in a city, given GPS traces collected by on-road vehicles. Their system finds the location and timing of traffic lights and stop-signs using a small...

    Provided By UC Regents

  • White Papers // Jul 2011

    TouchLogger: Inferring Keystrokes On Touch Screen From Smartphone Motion

    Attacks that use side channels, such as sound and electromagnetic emanation, to infer keystrokes on physical keyboards are ineffective on smartphones without physical keyboards. The authors describe a new side channel, motion, on touch screen smartphones with only soft keyboards. Since typing on different locations on the screen causes different...

    Provided By UC Regents

  • White Papers // Jul 2011

    Cooperative Jamming for Secure Communications in MIMO Relay Networks

    Secure communications can be impeded by eavesdroppers in conventional relay systems. This paper proposes cooperative jamming strategies for two-hop relay networks where the eavesdropper can wiretap the relay channels in both hops. In these approaches, the normally inactive nodes in the relay network can be used as cooperative jamming sources...

    Provided By UC Regents

  • White Papers // Jul 2011

    No Plan Survives Contact: Experience With Cybercrime Measurement

    An important mode of empirical security research involves analyzing the behavior, capabilities, and motives of adversaries. By definition, such measurements cannot be conducted in controlled settings and require "Engagement" directly with adversaries, their infrastructure or their ecosystem. However, the operational complexities required to successfully carry out such measurements are significant...

    Provided By UC Regents

  • White Papers // Jul 2011

    Improving the Way We Design Games for Learning by Examining How Popular Video Games Teach

    One of the reasons why commercial video games are popular is that they effectively teach players how to play the game - in many cases as the player plays the game itself. This paper focuses on how to effectively integrate teaching "How to play a game" with teaching an "Instructional...

    Provided By UC Regents

  • White Papers // Jul 2011

    Variability of Location Management Costs With Different Mobilities and Timer Periods to Update Locations

    In this paper, the authors examine the location management costs in mobile communication networks utilizing the timer-based method. From the study of the probabilities that a mobile terminal changes a number of Location Areas between two calls, they identify a threshold value of 0.7 for the Call-to-Mobility Ratio (CMR) below...

    Provided By UC Regents

  • White Papers // Jun 2011

    BOTMAGNIFIER: Locating Spambots on the Internet

    Unsolicited bulk email (spam) is used by cyber-criminals to lure users into scams and to spread malware infections. Most of these unwanted messages are sent by spam botnets, which are networks of compromised machines under the control of a single (malicious) entity. Often, these botnets are rented out to particular...

    Provided By UC Regents

  • White Papers // Jun 2011

    Measuring Pay-Per-Install: The Commoditization of Malware Distribution

    Recent years have seen extensive diversification of the "Underground economy" associated with malware and the subversion of Internet-connected systems. This trend towards specialization has compelling forces driving it: miscreants readily apprehend that tackling the entire value-chain from malware creation to monetization in the presence of ever-evolving countermeasures poses a daunting...

    Provided By UC Regents

  • White Papers // May 2011

    Authenticated and Misuse-Resistant Encryption of Key-Dependent Data

    This paper provides a comprehensive treatment of the security of Authenticated Encryption (AE) in the presence of key-dependent data, considering the four variants of the goal arising from the choice of universal nonce or random nonce security and presence or absence of a header. The authors present attacks showing that...

    Provided By UC Regents

  • White Papers // May 2011

    Just-in-Time Compilation for FPGA Processor Cores

    Portability benefits have encouraged the trend of distributing applications using processor-independent instructions, a.k.a. bytecode, and executing that bytecode on an emulator running on a target processor. Transparent Just-In-Time (JIT) compilation of bytecode to native instructions is often used to increase application execution speed without sacrificing portability. Recent work has proposed...

    Provided By UC Regents

  • White Papers // May 2011

    Concurrently Secure Computation in Constant Rounds

    The authors study the problem of constructing concurrently secure computation protocols in the plain model, where no trust is required in any party or setup. While the well established UC framework for concurrent security is impossible to achieve in this setting, a meaningful notion of concurrent security based on Super-Polynomial...

    Provided By UC Regents

  • White Papers // May 2011

    RFID Assisted Vehicle Positioning in VANETs

    With technological advancement, recent VANET applications such as safe driving and emergency rescue often demand high position accuracy. Unfortunately, however, conventional localization systems, e.g., GPS, hardly meet new accuracy requirements. To overcome this limitation, this paper proposes an RFID-assisted localization system. The proposed system employs the DGPS concept to improve...

    Provided By UC Regents

  • White Papers // May 2011

    Exploring the Effects of Feed-Forward and Feedback on Information Disclosure and User Experience in a Context-Aware Recommender System

    When disclosing information to a recommender system, users need to trade off its usefulness for receiving better recommendations with the privacy risks incurred through its disclosure. The paper describes a series of studies that will investigate the use of feed-forward and feedback messages to inform users about the potential usefulness...

    Provided By UC Regents

  • White Papers // May 2011

    Some Issues in WSN, MANET and Cellular Security

    In this position paper, the authors address some current limitations and challenges as well as emerging directions in three related areas of secure communication: security in Wireless Sensor Networks - WSNs, security in Mobile Ad hoc NETworks - MANETs, and security in Cellular Phone Networks. Sensors that obtain information by...

    Provided By UC Regents

  • White Papers // May 2011

    Analyzing Interaction Communication Networks in Enterprises and Identifying Hierarchies

    With the proliferation of electronic modes of communication (e.g., e-mails, short messages), a group of people in an enterprise can form several distinct Communication Interaction Networks, or CINs for short. A CIN is essentially a graph representation of "Who talks to whom" among a group of individuals. In this paper,...

    Provided By UC Regents

  • White Papers // May 2011

    Correlated-Input Secure Hash Functions

    The authors undertake a general study of hash functions secure under correlated inputs, meaning that security should be maintained when the adversary sees hash values of many related high-entropy inputs. Such a property is satisfied by a random oracle, and its importance is illustrated by study of the "Avalanche effect,"...

    Provided By UC Regents

  • White Papers // May 2011

    Database-Agnostic Transaction Support for Cloud Infrastructures

    In this paper, the authors present and empirically evaluate the performance of Database-Agnostic Transaction (DAT) support for the cloud. Their design and implementation of DAT is scalable, fault-tolerant, and requires only that the datastore provide atomic, row-level access. Their approach enables applications to employ a single transactional datastore API that...

    Provided By UC Regents

  • White Papers // May 2011

    SAIL: A Scalable Approach for Wide-Area IP Mobility

    The Internet is becoming increasingly mobile, with not only smartphones outnumbering stationary hosts, but also cars, buses, trains and airplanes all coming online. This makes Internet mobility support more important than ever. However, the existing standard mobility support protocols, mainly Mobile IPv6 and NEtwork MObility (NEMO), suffer from triangle routing...

    Provided By UC Regents

  • White Papers // May 2011

    On the Symmetry of User Mobility in Wireless Networks

    In this paper analyzed WLAN - GPS -and synthetic traces that record mobility in a variety of network environments. The authors observe that from a macroscopic level, human mobility is symmetric. In other words, the number of users that move from point A to point B approximates the number of...

    Provided By UC Regents

  • White Papers // May 2011

    GQ: Practical Containment for Measuring Modern Malware Systems

    Measurement and analysis of modern malware systems such as botnets relies crucially on execution of specimens in a setting that enables them to communicate with other systems across the Internet. Ethical, legal, and technical constraints, however, demand containment of resulting network activity in order to prevent the malware from harming...

    Provided By UC Regents

  • White Papers // May 2011

    A Comparitive Study of Achievability of Security Against Related-Key Attack

    This paper begins with a practical contribution, namely a way to leverage the RKA security of blockciphers to provide RKA security for a suite of high-level primitives. This motivates a more general theoretical question, namely, when is it possible to transfer RKA security from a primitive P1 to a primitive...

    Provided By UC Regents

  • White Papers // Apr 2011

    Seeker - A Bandwidth-Based Association Control Framework for Wireless Mesh Networks

    The rapid deployment of wireless mesh networks across universities and enterprises, and the pervasiveness of mobile devices equipped with Wi-Fi connectivity, has resulted in a scenario wherein end users have the option to choose from a multitude of access points at any given location. Moreover, with the increasing availability of...

    Provided By UC Regents

  • White Papers // Apr 2011

    Programming Support for Distributed Optimization and Control in Cyber-Physical Systems

    Large-scale actuator control problems in Cyber-Physical Systems (CPSs) are often expressed within the networked optimization model. While significant advances have taken place in optimization techniques, their widespread adoption in practical implementations is impeded by the complexity of inter-node coordination and lack of programming support that is necessary for sharing information...

    Provided By UC Regents

  • White Papers // Apr 2011

    (Im)Possible Frontiers: A Comment

    The existence of mean-variance efficient positive portfolios - portfolios with no negative weights - is a key requirement for equilibrium in the Capital Asset Pricing Model (CAPM). Brennan and Lo (2010) define an "Impossible frontier" as a frontier on which all portfolios have at least one negative weight. They prove...

    Provided By UC Regents

  • White Papers // Apr 2011

    Collusion-Resilient Quality of Information Evaluation Based on Information Provenance

    The quality of information is crucial for decision making in many dynamic information sharing environments such as sensor and tactical networks. Information trustworthiness is an essential parameter in assessing the information quality. In this paper, the authors present a trust model to evaluate the trustworthiness of information as well as...

    Provided By UC Regents

  • White Papers // Apr 2011

    Systemic Sovereign Credit Risk: Lessons From The U.S. And Europe

    The authors study the nature of systemic sovereign credit risk using CDS spreads for the U.S. Treasury, individual U.S. states, and major European countries. Using a multifactor affine framework that allows for both systemic and sovereign-specific credit shocks, they find that there is considerable heterogeneity across U.S. and European issuers...

    Provided By UC Regents

  • White Papers // Apr 2011

    Digitizing Physical Objects in the Home

    Technology in the home has brought about a number of changes in the way things are being done. Particularly interesting is the question as to whether some ways of doing activities are now being replaced given the availability of technology at an affordable cost. The ownership of a home computer...

    Provided By UC Regents

  • White Papers // Mar 2011

    Database Scalability, Elasticity, and Autonomy in the Cloud

    The proliferation of technology in the past two decades has created an interesting dichotomy for users. There is very little disagreement that an individual's life is significantly enriched as a result of easy access to information and services using a wide spectrum of computing platforms such as personal workstations, laptop...

    Provided By UC Regents

  • White Papers // Mar 2011

    SenSec: A Scalable and Accurate Framework for Wireless Sensor Network Security Evaluation

    The use of Wireless Sensor Networks (WSNs) is expanding rapidly in a variety of fields. As the use of sensors evolves from merely capturing data to real-time event detection and response, sensor networks must provide accurate and authentic data to guarantee operational integrity. Security solutions are necessary to prevent malicious...

    Provided By UC Regents

  • White Papers // Mar 2011

    Learning From Repetitive Acquisitions: Evidence From The Time Between Deals

    Repetitive acquisitions involve benefits and costs. Benefits accrue from learning about the takeover process while costs involve integrating the combined firms. These benefits and costs are not directly observable from outside the firm but this paper proposes a simple model to infer their relative importance from the time between successive...

    Provided By UC Regents

  • White Papers // Mar 2011

    Usability of Display-Equipped RFID Tags for Security Purposes

    Recent emergence of high-end RFID tags capable of performing public key operations enables some new applications in commerce (e.g., RFID-enabled credit cards) and security (e.g., ePassports and access control badges). While the use of public key cryptography mitigates many difficult security issues, certain important usability-related issues remain, particularly, when RFID...

    Provided By UC Regents

  • White Papers // Apr 2009

    TRUST:A General Framework for Truthful Double Spectrum Auctions (Extended)

    The authors design truthful double spectrum auctions where multiple parties can trade spectrum based on their individual needs. Open, market-based spectrum trading motivates existing spectrum owners (as sellers) to lease their selected idle spectrum to new spectrum users, and provides new users (as buyers) the spectrum they desperately need. The...

    Provided By UC Regents

  • White Papers // Apr 2009

    Strongly Regular Grammars and Regular Approximation of Context-Free Languages

    The authors consider algorithms for approximating context - free grammars by regular grammars, making use of Chomsky's characterization of non-self-embedding grammars as generating regular languages and a transformation by Mohri and Nederhof on sets of mutually recursive non-terminals. They give an exposition of strongly regular grammars and this transformation, and...

    Provided By UC Regents

  • White Papers // Aug 2009

    Thread Cooperation in Multicore Architectures for Frequency Counting Over Multiple Data Streams

    Many real-world data stream analysis applications such as network monitoring, click stream analysis and others require combining multiple streams of data arriving from multiple sources. This is referred to as multi-stream analysis. To deal with high stream arrival rates, it is desirable that such systems be capable of supporting very...

    Provided By UC Regents

  • White Papers // Jun 2009

    Anonymizing Edge-Weighted Social Network Graphs

    The increasing popularity of social networks has initiated a fertile research area in information extraction and data mining. Although such analysis can facilitate better understanding of sociological, behavioral, and other interesting phenomena, there is growing concern about personal privacy being breached, thereby requiring effective anonymization techniques. If the authors consider...

    Provided By UC Regents

  • White Papers // Jan 2009

    On Stateless Multicounter Machines

    The authors investigate the computing power of stateless multicounter machines with reversal-bounded counters. Such a machine hasm-counters operating on a one-way input delimited by left and right end markers. The move of the machine depends only on the symbol under the input head and the signs of the counters (zero...

    Provided By UC Regents

  • White Papers // Nov 2008

    Clouded Data: Comprehending Scalable Data Management Systems

    Managing petabytes of data for millions of users has been a challenge for big internet based enterprises such as Google, Yahoo!, and Amazon. Even though database management systems have a long history of managing enterprise level data and information, they are deemed to be unsuitable in this context. This resulted...

    Provided By UC Regents

  • White Papers // Nov 2008

    Gaussian Elimination Based Algorithms on the GPU

    The authors implemented and evaluated several Gaussian elimination based algorithms on Graphic Processing Units (GPUs). These algorithms, LU decomposition without pivoting, all-pairs shortest-paths, and transitive closure, all have similar data access patterns. The impressive computational power and memory bandwidth of the GPU make it an attractive platform to run such...

    Provided By UC Regents

  • White Papers // Jan 2011

    Efficient Algorithms and Routing Protocols for Handling Transient Single Node Failures

    Single node failures represent more than 85% of all node failures in the today's large communication networks such as the Internet. Also, these node failures are usually transient. Consequently, having the routing paths globally recomputed does not pay off since the failed nodes recover fairly quickly, and the recomputed routing...

    Provided By UC Regents

  • White Papers // Jan 2011

    MIST: Distributed Indexing and Querying in Sensor Networks using Statistical Models

    The modeling of high level semantic events from low level sensor signals is important in order to understand distributed phenomena. For such content-modeling purposes, transformation of numeric data into symbols and the modeling of resulting symbolic sequences can be achieved using statistical models - Markov Chains (MCs) and Hidden Markov...

    Provided By UC Regents

  • White Papers // Dec 2010

    Managing Traffic Growth in Next-Generation Telecom Networks

    This dissertation investigates how to optimally manage the traffic and its growth as well as the resources in a telecom network using optical Wavelength-Division Multiplexing (WDM) technology. A part of this dissertation addresses the Traffic Engineering (TE) problem, which determines how to set up explicit routes between source-destination pairs for...

    Provided By UC Regents

  • White Papers // Dec 2009

    Adaptivity in Data Stream Mining

    In recent years data streams became a ubiquitous source of information, and thus stream mining emerged as a new field in database research. Due to the inherently dynamic nature of data streams, stream mining algorithms benefit from being adaptive to changes in the properties of a data stream. In addition,...

    Provided By UC Regents

  • White Papers // Jul 2011

    Improving the Way We Design Games for Learning by Examining How Popular Video Games Teach

    One of the reasons why commercial video games are popular is that they effectively teach players how to play the game - in many cases as the player plays the game itself. This paper focuses on how to effectively integrate teaching "How to play a game" with teaching an "Instructional...

    Provided By UC Regents

  • White Papers // Aug 2011

    Improved Spectrum Access Control of Cognitive Radios Based on Primary ARQ Signals

    Cognitive radio systems capable of opportunistic spectrum access represent a new paradigm for improving the efficiency of current spectrum utilization. In this paper, the authors present a novel cognitive channel access method based on learning from both primary channel transmissions and the receiver ARQ feedback signals. This new sensing-plus-confirmation scheme...

    Provided By UC Regents

  • White Papers // May 2009

    Optimal Transmission Strategies for Dynamic Spectrum Access in Cognitive Radio Networks

    Cognitive radio offers a promising technology to mitigate spectrum shortage in wireless communications. It enables Secondary Users (SUs) to opportunistically access low-occupancy primary spectral bands as long as their negative effect on the Primary User (PU) access is constrained. This PU protection requirement is particularly challenging for multiple SUs over...

    Provided By UC Regents

  • White Papers // Sep 2009

    Cognitive Spectrum Access Control Based on Intrinsic Primary ARQ Information

    The authors explore a flexible and non-intrusive opportunistic spectrum access control mechanism for cognitive radios that goes beyond the standard "Listen-Before-Talk" (LBT) strategy. They exploit the bi-directional nature of many primary communication systems to control cognitive radio access that is based on both spectral sensing and primary receiver acknowledgements. In...

    Provided By UC Regents

  • White Papers // Feb 2009

    Feedback-Based Access and Power Control for Distributed Multiuser Cognitive Networks

    Cognitive radio networks enable secondary users to utilize spare bandwidth of primary users by limiting their interference. Moving beyond the traditional listen-before-talk paradigm, the authors propose a cognitive access methodology that exploits the feedback channel in two-way primary communication links for better spectrum utility and protection against interference. They let...

    Provided By UC Regents

  • White Papers // Jan 2011

    Traffic-Tracing Gateway (TTG)

    Traffic density in wireless networks is time- and space-varying as users move from one area to another. For example, the majority of traffic stays in residential areas in the early morning and late evening; but moves to business or commercial areas in daytime. Therefore, it is challenging to efficiently locate...

    Provided By UC Regents

  • White Papers // Aug 2008

    Short Paper: On Optimal Sensing and Transmission Strategies for Dynamic Spectrum Access

    The Listen-Before-Talk (LBT) strategy has been prevalent in cognitive radio networks where secondary users opportunistically access under-utilized primary band. To minimize the amount of disruption from secondary users to primary signals, secondary users generally are required to detect the presence of the primary user reliably, and access the spectrum intelligently....

    Provided By UC Regents

  • White Papers // Aug 2008

    Opportunistic Spectrum Access in Heterogeneous User Environments

    Cognitive Radio (CR) is an attractive technology to alleviate spectrum scarcity in wireless communications. It allows Secondary Users (SUs) to opportunistically access the licensed spectrum of primary users (PUs) so long as these users' communications are protected. Therefore, protection of the PUs is central to the adoption of this technology....

    Provided By UC Regents

  • White Papers // Aug 2009

    Markov Decision Process (MDP) Framework for Optimizing Software on Mobile Phones

    The authors present a framework based on Markov decision process to optimize software on mobile phones. Unlike previous approaches in literature that focus on energy optimization while meeting a specific task-related time constraint, they model the desired talk-time as an explicit user given parameter and formulate the optimization of resources...

    Provided By UC Regents

  • White Papers // Dec 2009

    Distributed Power Control for Cognitive User Access Based on Primary Link Control Feedback

    The authors venture beyond the "Listen-before-talk" strategy that is common in many traditional cognitive radio access schemes. They exploit the bi-directional nature of most primary communication systems. By intelligently choosing their transmission parameters based on the observation of Primary User (PU) communications, Secondary Users (SUs) in a cognitive network can...

    Provided By UC Regents

  • White Papers // Jan 2010

    Throughput Improvement in 802.11 WLANs Using Collision Probability Estimates in Link Adaptation

    The 802.11 standard includes several modulation rates, each of which is optimal for a different channel condition. However, there are no simple and reliable methods for nodes to determine their current channel conditions. Existing link adaptation techniques use packet losses as an indication of poor channel conditions; however, when there...

    Provided By UC Regents

  • White Papers // Jul 2010

    Packet Length Adaptation in WLANs With Hidden Nodes and Time-Varying Channels

    In a Wireless Local Area Network (LAN), packets can be lost due to a multitude of reasons. It is possible to reduce the probability of occurrence of some of these loss mechanisms by reducing packet length at the Medium Access Control (MAC) layer. However, using shorter packets decreases efficiency with...

    Provided By UC Regents

  • White Papers // Aug 2009

    Local Estimation of Probabilities of Direct and Staggered Collisions in 802.11 WLANs

    Current 802.11 networks do not typically achieve the maximum potential throughput despite link adaptation and cross-layer optimization techniques designed to alleviate many causes of packet loss. A primary contributing factor is the difficulty in distinguishing between various causes of packet loss, including collisions caused by high network use, co-channel interference...

    Provided By UC Regents

  • White Papers // May 2009

    Adaptive Packetization for Error-Prone Transmission Over 802.11 WLANs With Hidden Terminals

    Collision and fading are the two main sources of packet loss in Wireless Local Area Networks (WLANs) and as such, both are affected by the packetization at the Medium Access Control (MAC) layer. While a larger packet is preferred to balance protocol header overhead, a shorter packet is less vulnerable...

    Provided By UC Regents

  • White Papers // Jul 2010

    Collection of Time series of appetite-related sensations using a handheld computer: a case study

    The authors present a case study in the design and subsequent use of "OKMO", a software program for the quantitative assessment of subjective appetite-related sensations, using a visual scale and running on a handheld computing device. OKMO runs on inexpensive Palm devices (PalmOS 4), and was built using only free...

    Provided By UC Regents

  • White Papers // Oct 2010

    The Combinatorial BLAS: Design, Implementation, and Applications

    This paper presents a scalable high-performance software library to be used for graph analysis and data mining. Large combinatorial graphs appear in many applications of high-performance computing, including computational biology, informatics, analytics, web search, dynamical systems, and sparse matrix methods. Graph computations are difficult to parallelize using traditional approaches due...

    Provided By UC Regents

  • White Papers // Sep 2010

    Scalable Nearest Neighbors with Guarantees in Large and Composite Networks

    The authors address the problem of k Nearest Neighbor (kNN) search in networks, according to a random walk proximity measure called Effective Importance. Their approach retrieves the exact top neighbors at query time without relying on off-line indexing or summaries of the entire network. This makes it suitable for very...

    Provided By UC Regents

  • White Papers // Jul 2010

    Concurrent Collection as an Operating System Service for Cross-Runtime Cross-Language Memory Management

    The authors present GC-as-a-Service (GaS), a cross-runtime, cross-language Garbage Collection (GC) library that can be used to simplify the implementation of runtime systems, and that exploits available multicore technologies. GaS decouples GC from other runtime components and exposes a fine-grain API for use by GC-cooperative runtimes of different programming languages...

    Provided By UC Regents

  • White Papers // Aug 2010

    Understanding the Potential of Interpreter-based Optimizations for Python

    The increasing popularity of scripting languages as general purpose programming environments calls for more efficient execution. Most of these languages, such as Python, Ruby, PHP, and JavaScript are interpreted. Interpretation is a natural implementation given the dynamic nature of these languages and interpreter portability has facilitated wide-spread use. In this...

    Provided By UC Regents

  • White Papers // Jul 2010

    HengHa: Data Harvesting Detection on Hidden Databases

    The back-end databases of web-based applications are a major data security concern to enterprises. The problem becomes more critical with the proliferation of enterprises hosted web applications in the cloud. While much prior work has concentrated on the malicious attacks that try to break into the database by using vulnerabilities...

    Provided By UC Regents

  • White Papers // Jul 2010

    TranslatAR: A Mobile Augmented Reality Translator on the Nokia N900

    Researchers have long been interested in the synergy between portability and computing power but had been limited by unwieldy, uncommonly used devices. The latest generation of mobile phones, i.e. 'Smartphones', are equipped with hardware powerful enough to develop novel, interesting applications which allow users to directly interact with the world...

    Provided By UC Regents

  • White Papers // Jun 2010

    Highly Parallel Sparse Matrix-Matrix Multiplication

    Generalized sparse matrix-matrix multiplication is a key primitive for many high performance graph algorithms as well as some linear solvers such as multigrid. The authors present the first parallel algorithms that achieve increasing speedups for an unbounded number of processors. Their algorithms are based on two-dimensional block distribution of sparse...

    Provided By UC Regents

  • White Papers // Jul 2010

    Live Database Migration for Elasticity in a Multitenant Database for Cloud Platforms

    The growing popularity of cloud computing as a platform for deploying internet scale applications has seen a large number of web applications being deployed in the cloud. These applications (or tenants) are typically characterized by small data footprints, different schemas, and variable load patterns. Scalable multitenant DataBase Management Systems (DBMS)...

    Provided By UC Regents

  • White Papers // Apr 2010

    Who's Driving this Cloud? Towards Efficient Migration for Elastic and Autonomic Multitenant Databases

    The success of cloud computing as a platform for deploying web-applications has led to a deluge of applications characterized by small data footprints but unpredictable access patterns. An autonomic and scalable multitenant DataBase Management System (DBMS) is therefore an important component of the software stack for platforms supporting these applications....

    Provided By UC Regents

  • White Papers // Mar 2010

    ElasTraS: An Elastic, Scalable, and Self Managing Transactional Database for the Cloud

    Cloud computing has emerged as a pervasive platform for deploying scalable and highly available Internet applications. To facilitate the migration of data-driven applications to the cloud: elasticity, scalability, fault-tolerance, and self-manageability (henceforth referred to as cloud features) are fundamental requirements for DataBase Management Systems (DBMS) driving such applications. Even though...

    Provided By UC Regents

  • White Papers // Feb 2010

    Key-Value Datastores Comparison in AppScale

    The authors present a simple framework that employs a single API - the Datastore API from the Google App Engine cloud computing platform - to interface to different open source distributed database technologies in use today. They use the framework to "Plug in" different databases to the API so that...

    Provided By UC Regents

  • White Papers // Oct 2009

    Vshmem: Shared-Memory OS-Support for Multicore-based HPC systems

    As a result of the huge performance potential of multi-core microprocessors, HPC infrastructures are rapidly integrating them into their architectures in order to expedite the performance growth of the next generation HPC systems. However, as the number of cores per processor increase to 100 or 1000s of cores, they are...

    Provided By UC Regents

  • White Papers // Aug 2009

    Verification of String Manipulating Programs Using Multi-Track Automata

    Verification of string manipulation operations is a crucial problem in computer security. The authors present a new symbolic string verification technique that can be used to prove that vulnerabilities that result from improper string manipulation do not exist in a given program. They formally characterize the string verification problem as...

    Provided By UC Regents

  • White Papers // Aug 2009

    Tackling Bidder Collusion in Dynamic Spectrum Auctions (Extended)

    Dynamic spectrum auction is an effective solution to manage spectrum across many small networks. As the number of participants grows, collusion poses a serious threat to auction performance. Small groups of colluding bidders can make use of the interference constraints to manipulate auction outcomes, leading to unfair spectrum distribution and...

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