University of Connecticut

Displaying 1-40 of 54 results

  • White Papers // Jul 2012

    Exploiting the Error-Correcting Capabilities of Low Density Parity Check Codes in Distributed Video Coding using Optical Flow

    The authors consider Distributed Video Coding (DVC) in presence of communication errors. Thereafter methods for exploiting the error-correcting capabilities of the LDPCA code in DVC are investigated. The proposed frame interpolation includes a symmetric flow constraint to the standard forward-backward frame interpolation scheme, which improves quality and handling of large...

    Provided By University of Connecticut

  • White Papers // Sep 2011

    NAMS: A Networked Acoustic Modem System for Underwater Applications

    In this paper, the authors present a Networked Acoustic Modem System (NAMS) by integrating a high-speed OFDM modem and a comprehensive underwater network protocol stack for underwater applications. This integrated system allows different underwater network protocols to run on top of the OFDM modem platform and can provide high-speed, reliable...

    Provided By University of Connecticut

  • White Papers // Aug 2011

    Per-Cluster-Prediction Based Sparse Channel Estimation for Multicarrier Underwater Acoustic Communications

    In this paper, the authors present a sparse channel estimator for Zero-Padded Orthogonal Frequency Division Multiplexing (ZP-OFDM) modulation in clustered sparse UnderWater Acoustic (UWA) channels. The proposed channel estimator consists of two stages. In the first stage, channel prediction from the previous block to the current block is carried out...

    Provided By University of Connecticut

  • White Papers // Jul 2011

    Blind CFO Estimation for Zero-Padded OFDM Over Underwater Acoustic Channels

    In this paper, the authors studied the use of three existing blind CFO estimation algorithms for ZP-OFDM transmissions in underwater acoustic channels. They provided both numerical and experimental results. Simulations showed that the Y-G algorithm can perform as well as the null subcarrier based method, while having lower complexity, as...

    Provided By University of Connecticut

  • White Papers // Jul 2011

    Adaptive Routing in Underwater Delay Tolerant Sensor Networks

    Underwater Sensor Network (UWSN) has attracted significant attention from both academia and industry. Different from terrestrial sensor nodes, underwater sensor nodes are usually mobile, much bigger, more energy-consuming, harder to recharge and suffer from more severe environmental conditions. Thus, an UWSN can be easily partitioned and no persistent routes from...

    Provided By University of Connecticut

  • White Papers // Apr 2011

    Turbo Equalization for OFDM Modulated Physical Layer Network Coding

    In this paper, the authors consider a practical Orthogonal Frequency Division Multiplexing (OFDM) modulated and Low-Density Parity-Check (LDPC) channel coded two-way relay system employing Physical-Layer Network Coding (PLNC), where two terminals A and B desire to exchange information with each other with the help of a relay R which can...

    Provided By University of Connecticut

  • White Papers // Feb 2011

    MobiCom 2010 Poster: Passive Online Wireless LAN Health Monitoring From a Single Measurement Point

    Wireless LANs that are deployed in corporations and university campuses can contain a large number of access points and wireless hosts. In this paper, the authors develop a scalable approach that relies on measurements collected by a single monitor for WLAN health monitoring. They propose two metrics, local RTT and...

    Provided By University of Connecticut

  • White Papers // Feb 2011

    SDC: A Distributed Clustering Protocol

    Network clustering is an important technique used in many large-scale distributed systems. Given good design and implementation, network clustering can significantly enhance the system's scalability and efficiency. However, it is very challenging to design a good clustering protocol for networks that scale fast and change continuously. In this paper, the...

    Provided By University of Connecticut

  • White Papers // Jan 2011

    Dynamic Isoline Extraction for Visualization of Streaming Data

    Queries over streaming data offer the potential to provide timely information for modern database applications, such as sensor networks and web services. Isoline-based visualization of streaming data has the potential to be of great use in such applications. Dynamic (real-time) isoline extraction from the streaming data is needed in order...

    Provided By University of Connecticut

  • White Papers // Nov 2010

    The Issuer-Pay Rating Model And Rating Inflation: Evidence From Corporate Credit Ratings

    The author demonstrates that the issuer-pay rating model adopted by major credit rating agencies contributes to their incentives to issue inflated ratings. Employing a unique dataset, the author compare credit ratings based on the issuer-pay rating model to those based on the investor-pay model. The author finds that when the...

    Provided By University of Connecticut

  • White Papers // Nov 2010

    Progressive MIMO-OFDM Reception Over Time-Varying Underwater Acoustic Channels

    MIMO-OFDM has been actively studied for high data rate communications over the bandwidth-limited UnderWater Acoustic (UWA) channels. Unlike existing receivers that treat the InterCarrier Interference (ICI) as additive noise, in this paper, the authors deal with ICI explicitly together with the Co-Channel Interference (CCI) due to parallel transmissions in MIMO-OFDM....

    Provided By University of Connecticut

  • White Papers // Oct 2010

    A Paradigm for Channel Assignment and Data Migration in Distributed Systems

    In this paper, the authors consider the problems of channel assignment in wireless networks and data migration in heterogeneous storage systems. They show that a soft edge coloring approach to both problems gives rigorous approximation guarantees. In the channel assignment problem arising in wireless networks, they are given a graph...

    Provided By University of Connecticut

  • White Papers // Sep 2010

    Is the Cheating Risk Always Higher in Online Instruction Compared to Face-to-Face Instruction?

    This paper analyzes the exposure to cheating risk of online courses relative to face-to-face courses at a single institution. For a sample of 20 online courses the authors report that the cheating risk is higher than for equivalent face-to-face courses because of reliance on un-proctored multiple choice exams. The authors...

    Provided By University of Connecticut

  • White Papers // Aug 2010

    Underwater Localization Based on Multicarrier Waveforms

    In this paper, the authors investigate the problem of localizing an underwater sensor node based on message broadcasting from multiple surface nodes. With the time-of-arrival measurements from a DSP-based multicarrier modem, each sensor node localizes itself based on the travel time differences among multiple senders to the receiver. Using one-way...

    Provided By University of Connecticut

  • White Papers // Aug 2010

    A Factor-Graph Based ZP-OFDM Receiver for Deep Water Acoustic Channels

    In this paper, the authors present a factor-graph based receiver for Zero-Padded Orthogonal Frequency Division Multiplexing (ZP-OFDM) transmissions over deep water channels with extremely long delay spreads. Due to the geometric structure of deep oceans, the channel delay spread between the direct paths and surface/bottom reflections can be on the...

    Provided By University of Connecticut

  • White Papers // Aug 2010

    Blind Channel Shortening for Zero-Padded OFDM

    When the channel delay spread is larger than the guard interval of Zero-Padded (ZP) OFDM transmissions, InterBlock Interference (IBI) might lead to significant performance degradation. Without altering the signal design, a Time-domain EQualizer (TEQ) can be applied at the receiver to shorten the channel for IBI suppression. In this paper,...

    Provided By University of Connecticut

  • White Papers // Jul 2010

    Prediction Assisted Single-Copy Routing in Underwater Delay Tolerant Networks

    One challenge in Delay Tolerant Networks (DTNs) is efficient routing, as the lack of contemporaneous end-to-end paths makes conventional routing schemes inapplicable. Many existing DTN routing protocols adopt multi-copy replication and/or are incognizant of mobility models. Hence they are not suitable for networks with extremely stringent resources and time-varying mobility...

    Provided By University of Connecticut

  • White Papers // Jul 2010

    Capability and Fidelity of Mote-Class Wireless Sniffers

    Monitoring the health of a sensor network is important for maintaining the health and normal operation of the network. For large-scale cost-effective monitoring, using inexpensive motes as sniffers is an attractive choice. In this paper, the authors quantify the capability and fidelity of mote-class sniffers for sensor network monitoring. In...

    Provided By University of Connecticut

  • White Papers // Jun 2010

    Technical Appendix For ^Transitional Dynamics Of Dividend And Capital Gains Tax Cuts^

    In this appendix, the authors present the details of the extended model with debt in the paper "Transitional Dynamics of Dividend and Capital Gains Tax Cuts." Section 1 presents the extended model and results. Section 2 presents the numerical algorithm to solve this model. Section 3 presents an additional figure...

    Provided By University of Connecticut

  • White Papers // Apr 2010

    Iterative Sparse Channel Estimation and Decoding for Underwater MIMO-OFDM

    The authors propose a block-by-block iterative receiver for underwater MIMO-OFDM that couples channel estimation with Multiple-Input Multiple-Output (MIMO) detection and Low-Density Parity-Check (LDPC) channel decoding. In particular, the channel estimator is based on a compressive sensing technique to exploit the channel sparsity, the MIMO detector consists of a hybrid use...

    Provided By University of Connecticut

  • White Papers // Mar 2010

    COPE-MAC: A Contention-Based Medium Access Control Protocol With Parallel Reservation for Underwater Acoustic Networks

    Long propagation delays of acoustic signals in underwater networks pose grand challenges in Medium Access Control (MAC) protocol design, often significantly undermining network performance if not handled appropriately. In this paper, the authors propose a novel MAC protocol, called COntention based Parallel rEservation MAC (COPE-MAC) for underwater acoustic networks. In...

    Provided By University of Connecticut

  • White Papers // Mar 2010

    DSP Implementation of SISO and MIMO OFDM Acoustic Modems

    Significant progress has been made recently on the use of multicarrier modulation in the form of Orthogonal Frequency Division Multiplexing (OFDM) for high data rate underwater acoustic communications. This paper presents implementation results of OFDM acoustic modems under both single-input single-output and multi-input multi-output two transmitters and two receiver's settings....

    Provided By University of Connecticut

  • White Papers // Mar 2010

    Comparison of Basis Pursuit Algorithms for Sparse Channel Estimation in Underwater Acoustic OFDM

    UnderWater Acoustic (UWA) channels are doubly selective channels, having large delay spread and significant Doppler effects. Channel estimation, which is one critical task in the receiver design, is extremely challenging in the UWA communication context due to the large number of unknowns as a result of large delay and Doppler...

    Provided By University of Connecticut

  • White Papers // Mar 2010

    A Standard-Driven Implementation of WS-BPEL 2.0

    The authors present a systematic study of the WS-BPEL 2.0 standard based on two complementary methods: the process of constructing a new high-level WS-BPEL implementation driven by the structure of the standard, and an empirical evaluation of existing interpretations of the standard reflected in five widely available WS-BPEL-implementations, both commercial...

    Provided By University of Connecticut

  • White Papers // Mar 2010

    A Framework for the Sound Specification of Cryptographic Tasks

    Nowadays it is widely accepted to formulate the security of a protocol carrying out a given task via the "Trusted-party paradigm," where the protocol execution is compared with an ideal process where the outputs are computed by a trusted party that sees all the inputs. A protocol is said to...

    Provided By University of Connecticut

  • White Papers // Mar 2010

    Mobi-Sync: Efficient Time Synchronization for Mobile Underwater Sensor Networks

    Time synchronization is a critical service for distributed network systems. In this work, the authors investigate this problem in the context of Underwater Sensor Networks (UWSNs). Although there are many time synchronization protocols proposed for terrestrial wireless sensor networks, none of them could be directly applied to UWSNs. This is...

    Provided By University of Connecticut

  • White Papers // Feb 2010

    Efficient Vector-Based Forwarding for Underwater Sensor Networks

    UnderWater Sensor Networks (UWSNs) are significantly different from terrestrial sensor networks in the following aspects: low bandwidth, high latency, node mobility, high error probability, and 3-dimensional space. These new features bring many challenges to the network protocol design of UWSNs. In this paper, the authors tackle one fundamental problem in...

    Provided By University of Connecticut

  • White Papers // Feb 2010

    Vertical Partitioning of Relational OLTP Databases Using Integer Programming

    A way to optimize performance of relational row store databases is to reduce the row widths by vertically partitioning tables into table fractions in order to minimize the number of irrelevant columns/attributes read by each transaction. This paper considers vertical partitioning algorithms for relational row-store OLTP databases with an H-store-like...

    Provided By University of Connecticut

  • White Papers // Jan 2010

    Distributed Channel Assignment for Multi-Radio Wireless Networks

    This paper considers the channel assignment problem for multihop wireless networks in which nodes have multiple interfaces. Given the number of interfaces at each node and available channels in the system, the authors find a feasible channel assignment to improve network performance. Even when routing is given, finding a channel...

    Provided By University of Connecticut

  • White Papers // Dec 2009

    Pressure Routing for Underwater Sensor Networks

    A SEA Swarm (Sensor Equipped Aquatic Swarm) is a sensor cloud that drifts with water currents and enables 4D (Space and time) monitoring of local underwater events such as contaminants, marine life and intruders. The swarm is escorted at the surface by drifting sonobuoys that collect the data from underwater...

    Provided By University of Connecticut

  • White Papers // Dec 2009

    Delay Monitoring for Wireless Sensor Networks: An Architecture Using Air Sniffers

    Wireless sensor networks have been used for many delay-sensitive applications, e.g., emergency response and plant automation. In such networks, delay measurement is important for a number of reasons, e.g., real-time control of the networked system, and abnormal delay detection. In this paper, the authors propose a measurement architecture using distributed...

    Provided By University of Connecticut

  • White Papers // Dec 2009

    Evaluating Health Care Externality Costs Generated By Risky Consumption Goods

    The authors present an OverLapping-Generations (OLG) macroeconomic model that applies a behavioral interpretation of preferences for goods that generate health risks. In this paper, proneness to poor health is viewed as a cognitive miscalculation by economic agents between their expected health state over various consumption bundles and the actual health...

    Provided By University of Connecticut

  • White Papers // Nov 2009

    Economics And Policy Preferences: Causal Evidence Of The Impact of Economic Conditions On Support For Redistribution And Other Ballot Proposals

    Using California ballot proposition returns and exogenous shifts to labor demand, the authors provide the first large-scale causal evidence of the impact of economic conditions on policy preferences. In accord with economic theory, they find that positive economic shocks lead to large decreases in neighborhood residents' support for redistributive policies....

    Provided By University of Connecticut

  • White Papers // Oct 2009

    Workers' Compensation Resource Guide

    Workers' Compensation is a type of insurance intended to provide wage replacement, medical bill coverage, and other benefits to employees and their families due to occupational injuries and illnesses. It is a mandated program governed primarily by laws found in the Connecticut General Statutes. The Workers' Compensation program for state...

    Provided By University of Connecticut

  • White Papers // Sep 2009

    Target Tracking for Multistatic Radar With Transmitter Uncertainty

    The authors present a target tracking system for a specific sort of passive radar, that using a Digital Audio/Video Broadcast (DAB/DVB) network for illuminators of opportunity. The system can measure bi-static range and range-rate. Angular information is assumed here unavailable. The DAB/DVB network operates in a single frequency mode; this...

    Provided By University of Connecticut

  • White Papers // Sep 2009

    Randomness-Optimal Steganography

    Steganographic protocols enable one to "Embed" covert messages into inconspicuous data over a public communication channel in such a way that no one, aside from the sender and the intended receiver can even detect the presence of the secret message. In this paper, the authors provide a new provably-secure, private-key...

    Provided By University of Connecticut

  • White Papers // Sep 2009

    Efficient Steganography With Provable Security Guarantees

    The authors provide a new provably-secure steganographic encryption protocol that is proven secure in the complexity-theoretic framework of Hopper et al. The fundamental building block of the steganographic encryption protocol is a "One-time stegosystem" that allows two parties to transmit messages of length shorter than the shared key with information-theoretic...

    Provided By University of Connecticut

  • White Papers // Aug 2009

    Handling Triple Hidden Terminal Problems for Multi-Channel MAC in Long-Delay Underwater Sensor Networks

    In this paper, the authors investigate the multi-channel MAC problem in underwater acoustic sensor networks. To reduce hardware cost, only one acoustic transceiver is often preferred on every node. In a single-transceiver multichannel long-delay underwater network, new hidden terminal problems, namely multi-channel hidden terminal and long-delay hidden terminal (together with...

    Provided By University of Connecticut

  • White Papers // Jun 2009

    Analysis of the WS-BPEL 2.0 Standard Using Standard-Driven Implementation

    The authors present a systematic study of the OASIS WS-BPEL 2.0 standard (henceforth simply called BPEL) based on two complementary methods: the process of constructing a new high-level BPEL implementation driven by the structure of the standard, and an empirical evaluation of existing interpretations of the standard reflected in five...

    Provided By University of Connecticut

  • White Papers // Jun 2009

    Architectural Enhancement and System Software Support for Program Code Integrity Monitoring in Application-Specific Instruction Set Processors

    Program code in a computer system can be altered either by malicious security attacks or by various faults in microprocessors. At the instruction level, all code modifications are manifested as bit flips. In this work, the authors present a generalized methodology for monitoring code integrity at run-time in Application-Specific Instruction...

    Provided By University of Connecticut

  • White Papers // May 2009

    Fault Localization Using Passive End-to-End Measurement and Sequential Testing for Wireless Sensor Networks

    Faulty components in a network need to be localized and repaired to sustain the health of the network. This paper proposes a novel approach that carefully combines active and passive measurements to localize faults in wireless sensor networks. More specifically, the authors formulate a problem of optimal sequential testing guided...

    Provided By University of Connecticut

  • White Papers // Jun 2009

    Architectural Enhancement and System Software Support for Program Code Integrity Monitoring in Application-Specific Instruction Set Processors

    Program code in a computer system can be altered either by malicious security attacks or by various faults in microprocessors. At the instruction level, all code modifications are manifested as bit flips. In this work, the authors present a generalized methodology for monitoring code integrity at run-time in Application-Specific Instruction...

    Provided By University of Connecticut

  • White Papers // Dec 2009

    Pressure Routing for Underwater Sensor Networks

    A SEA Swarm (Sensor Equipped Aquatic Swarm) is a sensor cloud that drifts with water currents and enables 4D (Space and time) monitoring of local underwater events such as contaminants, marine life and intruders. The swarm is escorted at the surface by drifting sonobuoys that collect the data from underwater...

    Provided By University of Connecticut

  • White Papers // Oct 2010

    A Paradigm for Channel Assignment and Data Migration in Distributed Systems

    In this paper, the authors consider the problems of channel assignment in wireless networks and data migration in heterogeneous storage systems. They show that a soft edge coloring approach to both problems gives rigorous approximation guarantees. In the channel assignment problem arising in wireless networks, they are given a graph...

    Provided By University of Connecticut

  • White Papers // Jan 2009

    Comparison of Strategies for Serving Two Streams of Jobs

    Highly varying job demands generally consist of many short jobs mixed with several long jobs. In this paper, the authors consider a simple scenario where two job streams with different level of demands must be processed by the same server. They study the performance of several round-robin variants and FCFSP...

    Provided By University of Connecticut

  • White Papers // Jan 2009

    Analysis of Round-Robin Variants: Favoring Newly Arrived Jobs

    Highly varying job demands generally consist of many short jobs mixed with several long jobs. In principle, without fore knowledge of exact service times of individual jobs, processor sharing is an effective theoretical strategy for handling such demands. In practice, however, processor sharing must be implemented by time-slicing, which incurs...

    Provided By University of Connecticut

  • White Papers // Sep 2009

    Efficient Steganography With Provable Security Guarantees

    The authors provide a new provably-secure steganographic encryption protocol that is proven secure in the complexity-theoretic framework of Hopper et al. The fundamental building block of the steganographic encryption protocol is a "One-time stegosystem" that allows two parties to transmit messages of length shorter than the shared key with information-theoretic...

    Provided By University of Connecticut

  • White Papers // Sep 2009

    Randomness-Optimal Steganography

    Steganographic protocols enable one to "Embed" covert messages into inconspicuous data over a public communication channel in such a way that no one, aside from the sender and the intended receiver can even detect the presence of the secret message. In this paper, the authors provide a new provably-secure, private-key...

    Provided By University of Connecticut

  • White Papers // Jun 2010

    Technical Appendix For ^Transitional Dynamics Of Dividend And Capital Gains Tax Cuts^

    In this appendix, the authors present the details of the extended model with debt in the paper "Transitional Dynamics of Dividend and Capital Gains Tax Cuts." Section 1 presents the extended model and results. Section 2 presents the numerical algorithm to solve this model. Section 3 presents an additional figure...

    Provided By University of Connecticut

  • White Papers // Jan 2011

    Dynamic Isoline Extraction for Visualization of Streaming Data

    Queries over streaming data offer the potential to provide timely information for modern database applications, such as sensor networks and web services. Isoline-based visualization of streaming data has the potential to be of great use in such applications. Dynamic (real-time) isoline extraction from the streaming data is needed in order...

    Provided By University of Connecticut

  • White Papers // Mar 2010

    A Framework for the Sound Specification of Cryptographic Tasks

    Nowadays it is widely accepted to formulate the security of a protocol carrying out a given task via the "Trusted-party paradigm," where the protocol execution is compared with an ideal process where the outputs are computed by a trusted party that sees all the inputs. A protocol is said to...

    Provided By University of Connecticut

  • White Papers // Nov 2010

    The Issuer-Pay Rating Model And Rating Inflation: Evidence From Corporate Credit Ratings

    The author demonstrates that the issuer-pay rating model adopted by major credit rating agencies contributes to their incentives to issue inflated ratings. Employing a unique dataset, the author compare credit ratings based on the issuer-pay rating model to those based on the investor-pay model. The author finds that when the...

    Provided By University of Connecticut

  • White Papers // Dec 2009

    Evaluating Health Care Externality Costs Generated By Risky Consumption Goods

    The authors present an OverLapping-Generations (OLG) macroeconomic model that applies a behavioral interpretation of preferences for goods that generate health risks. In this paper, proneness to poor health is viewed as a cognitive miscalculation by economic agents between their expected health state over various consumption bundles and the actual health...

    Provided By University of Connecticut

  • White Papers // Jul 2011

    Adaptive Routing in Underwater Delay Tolerant Sensor Networks

    Underwater Sensor Network (UWSN) has attracted significant attention from both academia and industry. Different from terrestrial sensor nodes, underwater sensor nodes are usually mobile, much bigger, more energy-consuming, harder to recharge and suffer from more severe environmental conditions. Thus, an UWSN can be easily partitioned and no persistent routes from...

    Provided By University of Connecticut

  • White Papers // Nov 2009

    Economics And Policy Preferences: Causal Evidence Of The Impact of Economic Conditions On Support For Redistribution And Other Ballot Proposals

    Using California ballot proposition returns and exogenous shifts to labor demand, the authors provide the first large-scale causal evidence of the impact of economic conditions on policy preferences. In accord with economic theory, they find that positive economic shocks lead to large decreases in neighborhood residents' support for redistributive policies....

    Provided By University of Connecticut

  • White Papers // Feb 2011

    MobiCom 2010 Poster: Passive Online Wireless LAN Health Monitoring From a Single Measurement Point

    Wireless LANs that are deployed in corporations and university campuses can contain a large number of access points and wireless hosts. In this paper, the authors develop a scalable approach that relies on measurements collected by a single monitor for WLAN health monitoring. They propose two metrics, local RTT and...

    Provided By University of Connecticut

  • White Papers // Feb 2010

    Efficient Vector-Based Forwarding for Underwater Sensor Networks

    UnderWater Sensor Networks (UWSNs) are significantly different from terrestrial sensor networks in the following aspects: low bandwidth, high latency, node mobility, high error probability, and 3-dimensional space. These new features bring many challenges to the network protocol design of UWSNs. In this paper, the authors tackle one fundamental problem in...

    Provided By University of Connecticut

  • White Papers // Aug 2009

    Handling Triple Hidden Terminal Problems for Multi-Channel MAC in Long-Delay Underwater Sensor Networks

    In this paper, the authors investigate the multi-channel MAC problem in underwater acoustic sensor networks. To reduce hardware cost, only one acoustic transceiver is often preferred on every node. In a single-transceiver multichannel long-delay underwater network, new hidden terminal problems, namely multi-channel hidden terminal and long-delay hidden terminal (together with...

    Provided By University of Connecticut

  • White Papers // May 2009

    Sniffer Channel Selection for Monitoring Wireless LA

    Wireless sniffers are often used to monitor APs in Wireless LANs (WLANs) for network management, fault detection, traffic characterization, and optimizing deployment. It is cost effective to deploy single-radio sniffers that can monitor multiple nearby APs. However, since nearby APs often operate on orthogonal channels, a sniffer needs to switch...

    Provided By University of Connecticut

  • White Papers // Apr 2010

    Iterative Sparse Channel Estimation and Decoding for Underwater MIMO-OFDM

    The authors propose a block-by-block iterative receiver for underwater MIMO-OFDM that couples channel estimation with Multiple-Input Multiple-Output (MIMO) detection and Low-Density Parity-Check (LDPC) channel decoding. In particular, the channel estimator is based on a compressive sensing technique to exploit the channel sparsity, the MIMO detector consists of a hybrid use...

    Provided By University of Connecticut

  • White Papers // Sep 2011

    NAMS: A Networked Acoustic Modem System for Underwater Applications

    In this paper, the authors present a Networked Acoustic Modem System (NAMS) by integrating a high-speed OFDM modem and a comprehensive underwater network protocol stack for underwater applications. This integrated system allows different underwater network protocols to run on top of the OFDM modem platform and can provide high-speed, reliable...

    Provided By University of Connecticut

  • White Papers // Jul 2011

    Blind CFO Estimation for Zero-Padded OFDM Over Underwater Acoustic Channels

    In this paper, the authors studied the use of three existing blind CFO estimation algorithms for ZP-OFDM transmissions in underwater acoustic channels. They provided both numerical and experimental results. Simulations showed that the Y-G algorithm can perform as well as the null subcarrier based method, while having lower complexity, as...

    Provided By University of Connecticut

  • White Papers // Aug 2011

    Per-Cluster-Prediction Based Sparse Channel Estimation for Multicarrier Underwater Acoustic Communications

    In this paper, the authors present a sparse channel estimator for Zero-Padded Orthogonal Frequency Division Multiplexing (ZP-OFDM) modulation in clustered sparse UnderWater Acoustic (UWA) channels. The proposed channel estimator consists of two stages. In the first stage, channel prediction from the previous block to the current block is carried out...

    Provided By University of Connecticut

  • White Papers // Apr 2011

    Turbo Equalization for OFDM Modulated Physical Layer Network Coding

    In this paper, the authors consider a practical Orthogonal Frequency Division Multiplexing (OFDM) modulated and Low-Density Parity-Check (LDPC) channel coded two-way relay system employing Physical-Layer Network Coding (PLNC), where two terminals A and B desire to exchange information with each other with the help of a relay R which can...

    Provided By University of Connecticut

  • White Papers // Nov 2010

    Progressive MIMO-OFDM Reception Over Time-Varying Underwater Acoustic Channels

    MIMO-OFDM has been actively studied for high data rate communications over the bandwidth-limited UnderWater Acoustic (UWA) channels. Unlike existing receivers that treat the InterCarrier Interference (ICI) as additive noise, in this paper, the authors deal with ICI explicitly together with the Co-Channel Interference (CCI) due to parallel transmissions in MIMO-OFDM....

    Provided By University of Connecticut

  • White Papers // Aug 2010

    Underwater Localization Based on Multicarrier Waveforms

    In this paper, the authors investigate the problem of localizing an underwater sensor node based on message broadcasting from multiple surface nodes. With the time-of-arrival measurements from a DSP-based multicarrier modem, each sensor node localizes itself based on the travel time differences among multiple senders to the receiver. Using one-way...

    Provided By University of Connecticut

  • White Papers // Aug 2010

    A Factor-Graph Based ZP-OFDM Receiver for Deep Water Acoustic Channels

    In this paper, the authors present a factor-graph based receiver for Zero-Padded Orthogonal Frequency Division Multiplexing (ZP-OFDM) transmissions over deep water channels with extremely long delay spreads. Due to the geometric structure of deep oceans, the channel delay spread between the direct paths and surface/bottom reflections can be on the...

    Provided By University of Connecticut

  • White Papers // Jul 2012

    Exploiting the Error-Correcting Capabilities of Low Density Parity Check Codes in Distributed Video Coding using Optical Flow

    The authors consider Distributed Video Coding (DVC) in presence of communication errors. Thereafter methods for exploiting the error-correcting capabilities of the LDPCA code in DVC are investigated. The proposed frame interpolation includes a symmetric flow constraint to the standard forward-backward frame interpolation scheme, which improves quality and handling of large...

    Provided By University of Connecticut

  • White Papers // Jan 2009

    Engineering an HL7 Interface and Wireless Infrastructure to Improve the Efficiency of ECG Analysis at Hartford Hospital

    This paper describes the integration of Hartford Hospital's current 12-lead electrocardiogram (ECG) software with the hospital's information systems (Admit, Discharge, Transfer (ADT); orders; and billing) by engineering a Health Level Seven Standard Interface (HL7) specifically for the hospital's unique software amalgamation. Data formats for the wireless transmission of information were...

    Provided By University of Connecticut

  • White Papers // Mar 2010

    DSP Implementation of SISO and MIMO OFDM Acoustic Modems

    Significant progress has been made recently on the use of multicarrier modulation in the form of Orthogonal Frequency Division Multiplexing (OFDM) for high data rate underwater acoustic communications. This paper presents implementation results of OFDM acoustic modems under both single-input single-output and multi-input multi-output two transmitters and two receiver's settings....

    Provided By University of Connecticut

  • White Papers // Sep 2010

    Is the Cheating Risk Always Higher in Online Instruction Compared to Face-to-Face Instruction?

    This paper analyzes the exposure to cheating risk of online courses relative to face-to-face courses at a single institution. For a sample of 20 online courses the authors report that the cheating risk is higher than for equivalent face-to-face courses because of reliance on un-proctored multiple choice exams. The authors...

    Provided By University of Connecticut

  • White Papers // Jan 2010

    Distributed Channel Assignment for Multi-Radio Wireless Networks

    This paper considers the channel assignment problem for multihop wireless networks in which nodes have multiple interfaces. Given the number of interfaces at each node and available channels in the system, the authors find a feasible channel assignment to improve network performance. Even when routing is given, finding a channel...

    Provided By University of Connecticut

  • White Papers // Jan 2009

    Approximation Algorithms for Data Broadcast in Wireless Networks

    Broadcasting is a fundamental operation in wireless networks and plays an important role in the communication protocol design. In multihop wireless networks, however, interference at a node due to simultaneous transmissions from its neighbors makes it non-trivial to design a minimum-latency broadcast algorithm, which is known to be NP-complete. This...

    Provided By University of Connecticut

  • White Papers // Oct 2009

    Workers' Compensation Resource Guide

    Workers' Compensation is a type of insurance intended to provide wage replacement, medical bill coverage, and other benefits to employees and their families due to occupational injuries and illnesses. It is a mandated program governed primarily by laws found in the Connecticut General Statutes. The Workers' Compensation program for state...

    Provided By University of Connecticut

  • White Papers // Feb 2011

    SDC: A Distributed Clustering Protocol

    Network clustering is an important technique used in many large-scale distributed systems. Given good design and implementation, network clustering can significantly enhance the system's scalability and efficiency. However, it is very challenging to design a good clustering protocol for networks that scale fast and change continuously. In this paper, the...

    Provided By University of Connecticut

  • White Papers // Mar 2010

    Mobi-Sync: Efficient Time Synchronization for Mobile Underwater Sensor Networks

    Time synchronization is a critical service for distributed network systems. In this work, the authors investigate this problem in the context of Underwater Sensor Networks (UWSNs). Although there are many time synchronization protocols proposed for terrestrial wireless sensor networks, none of them could be directly applied to UWSNs. This is...

    Provided By University of Connecticut

  • White Papers // Mar 2009

    Performance Enhancement of Web Server System

    The invention of the Internet has ushered in advances in information era which has revolutionized the way the authors conduct business, advances the knowledge and promote lifelong learning. Each second a web server computer is bombarded with queries from numerous clients. It is then the web server system that responds...

    Provided By University of Connecticut

  • White Papers // Jul 2010

    Prediction Assisted Single-Copy Routing in Underwater Delay Tolerant Networks

    One challenge in Delay Tolerant Networks (DTNs) is efficient routing, as the lack of contemporaneous end-to-end paths makes conventional routing schemes inapplicable. Many existing DTN routing protocols adopt multi-copy replication and/or are incognizant of mobility models. Hence they are not suitable for networks with extremely stringent resources and time-varying mobility...

    Provided By University of Connecticut

  • White Papers // Jul 2010

    Capability and Fidelity of Mote-Class Wireless Sniffers

    Monitoring the health of a sensor network is important for maintaining the health and normal operation of the network. For large-scale cost-effective monitoring, using inexpensive motes as sniffers is an attractive choice. In this paper, the authors quantify the capability and fidelity of mote-class sniffers for sensor network monitoring. In...

    Provided By University of Connecticut

  • White Papers // Dec 2009

    Delay Monitoring for Wireless Sensor Networks: An Architecture Using Air Sniffers

    Wireless sensor networks have been used for many delay-sensitive applications, e.g., emergency response and plant automation. In such networks, delay measurement is important for a number of reasons, e.g., real-time control of the networked system, and abnormal delay detection. In this paper, the authors propose a measurement architecture using distributed...

    Provided By University of Connecticut