| Mitigation Approaches for Optical Imaging through Clouds and Fog |
Nov-2009 |
191 pages |
| Authors:
Mohsen Kavehrad; PENNSYLVANIA STATE UNIV UNIVERSITY PARK
|
 | This report offers novel designs for active optical imaging through clouds and fog, motivated by many military applications, such as laser range-finder, target designation for seekers and laser radar. The report focuses on jointly-optimized wireless optical multi-input multi-output (MIMO) transceivers for through-clouds airborne active optical imaging systems. Photolithographic techniques are employed in designing the optical transceiver subsystems. Our design goal is to select the diversity receiver branches field-of-view (FOV) in ... |
|
| Lines of Energy Deposition for Supersonic/Hypersonic Temperature/ Drag-Reduction and Vehicle Control |
06-Oct-2009 |
15 pages |
| Authors:
Michael P Reilly; George H Miley; Kevin Kremeyer; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
|
| Lines of energy are deposited ahead of supersonic and hypersonic vehicles in order to create a low-density channel, through which a vehicle can travel with dramatically reduced drag. Temperature and pressure are both also reduced on the front surfaces of the vehicle, while density and pressure are increased at the vehicle base. When applied off-center, this technique can be used to control the vehicle, employing the entire body as the ... |
|
| Navy Nuclear Aircraft Carrier (CVN) Homeporting at Mayport: Background and Issues for Congress |
23-Sep-2009 |
|
| Authors:
Ronald O'Rourke; LIBRARY OF CONGRESS WASHINGTON DC CONGRESSIONAL RESEARCH SERVICE
|
 | On January 14, 2009, the Navy announced that it wants to transfer one of its nuclear-powered aircraft carriers (CVNs) to the Navy home port at Mayport, FL, known formally as Naval Station (NAVSTA) Mayport. On April 10, 2009, the Department of Defense (DOD) announced that it had decided to delay a final decision on whether to propose transferring a CVN to Mayport until it reviews the issue as part of ... |
|
| Performance Analysis of a Link-16/JTIDS Compatible Waveform With Noncoherent Detection, Diversity and Side Information |
Sep-2009 |
70 pages |
| Authors:
Ioannis Kagioglidis; NAVAL POSTGRADUATE SCHOOL MONTEREY CA DEPT OF ELECTRICAL AND COMPUTER ENGINEERING
|
| The Joint Tactical Information Distribution System (JTIDS) is a hybrid frequency-hopped, direct sequence spread spectrum system. A (31, 15) Reed-Solomon (RS) code is used for forward error correction coding, and cyclical code-shift keying (CCSK) M-ary modulation is used, where each encoded symbol represents five bits. In this thesis, a compatible waveform consistent with the existing JTIDS channel waveform is analyzed. The system considered uses the same (31, 15) RS encoding ... |
|
| Development of the Phase Synchronization Circuit for Wirelessly Distributed Digital Phased Array |
Sep-2009 |
129 pages |
| Authors:
Yen-Chang Tsai; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| The Wirelessly Distributed Digital Phased Array (WDDPA) is an ongoing research program at the Naval Postgraduate School (NPS) which has numerous possible applications in radar and communication systems. The WDDPA incorporates many array elements randomly or nonuniformly in the environment or on a platform. Array elements are synchronized and controlled over a wireless channel. Compared to conventional phased array systems, its advantages are adaptability, survivability and flexibility. Phase synchronization is ... |
|
| Monitoring of Streambank Stabilization and River Restoration Structures on Ice-Affected Rivers in Northern Vermont |
Aug-2009 |
59 pages |
| Authors:
Andrew M Tuthill; ENGINEER RESEARCH AND DEVELOPMENT CENTER HANOVER NH COLD REGIONS RESEARCH AND ENGINEERING LAB
|
| Modern river restoration and streambank stabilization designs are taking more natural approaches. Examples include vanes and weirs constructed of rocks or logs that encourage bank sedimentation and direct flow toward the channel center, also rock riffles and weirs to control grade. Successful projects help control bed and bank erosion, re-connect floodplains, increase flow diversity and improve habitat for fish and wildlife. To date, the design of these increasingly popular structures ... |
|
| Effect of a Compressive Uniaxial Strain on the Critical Current Density of Grain Boundaries in Superconducting YBa2Cu3O7-delta Films |
09-Jul-2009 |
6 pages |
| Authors:
T J Haugan; P N van der Barnes; D C Laan; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH PROPULSION DIRECTORATE
|
| The mechanism by which grain boundaries impede current flow in high-temperature superconductors has resisted explanation for over two decades. We provide evidence that the strain fields around grain boundary dislocations in YBa2Cu3O7-delta thin films substantially suppress the local critical current density Jc. The removal of strain from the superconducting grain boundary channels by the application of compressive strain causes a remarkable increase in Jc. Contrary to previous understanding, the strain-free ... |
|
| Enhancing the Delivery and Reception of Information Objects Over Deprived Channels and Computational Devices (Postprint) |
Jul-2009 |
12 pages |
| Authors:
John Spina; Ivan Bradaric; Gerard T Capraro; Christopher T Capraro; James M Scherzi; CAPRARO TECHNOLOGIES INC UTICA NY
|
| A brief history of mathematical information and communication theory is presented with examples to illustrate the communications aspects of transmitting and receiving information over a channel. We wish to extend these concepts and modify the messages or information objects themselves and yet maintain the meaning of the messages. Our approach is to reduce the quality of the original messages without severely degrading a message's intent before compressing the resultant messages ... |
|
| Successive Interference Cancellation in Rake Receiver for CDMA Signals |
Jun-2009 |
77 pages |
| Authors:
Stamatios Gkiokas; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| The objective of this thesis is to investigate various techniques of Successive Intracell Interference Cancellation (SIIC) for Wideband-Code Division Multiple Access (W-CDMA). These techniques can improve the performance of CDMA interceptors and enhance the operation of cellular mobile communication systems. The research focuses on the forward link (downlink) where orthogonal covering is employed. We examine three interference cancellation techniques that suppress the intracell multiuser interference. The first method is called ... |
|
| Gas Transport Through Channels |
25-Mar-2009 |
43 pages |
| Authors:
Walter F Boron; YALE UNIV NEW HAVEN CT SCHOOL OF MEDICINE
|
| The aforementioned grant supports all work related to Gas Channels in Walter Boron's laboratory. He and his colleagues published four papers that were supported by ONR funds awarded to Yale University during the above period. For the two papers published in 2009, the work was completed at Case Western Reserve University, supported by funds for the subsequent period of support. |
|
| Bit-Error-Rate-Minimizing Channel Shortening Using Post-FEQ Diversity Combining and a Genetic Algorithm |
10-Mar-2009 |
90 pages |
| Authors:
Gokhan Altin; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
|
| Channel shortening filter design is a widely examined topic in the literature. Most of the channel shortening equalizer proposals depend on perfect channel state information (CSI). However, this information may not be available in all situations. In cases where the channel state information is not needed, blind adaptive equalization techniques are appropriate. In wireline communication systems, the CSE design is based on maximizing the bit rate, but in wireless systems, ... |
|
| Design and Development of a Single Channel RSNS Direction Finder |
Mar-2009 |
95 pages |
| Authors:
Jessica A Benveniste; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| This thesis carried out the design and development of a single channel Robust Symmetrical Number System (RSNS) virtual spacing direction finding (DF) system. This was based on previous work on a three-channel RSNS virtual spacing DF system. Various moduli sets were chosen and run through MATLAB simulations. The results showed unacceptably large errors at low signal-to-noise ratios (SNRs) for all sets. Large dynamic range moduli sets yielded relatively high errors ... |
|
| Maximizing Situational Awareness: Improving Situational Awareness with Global Positioning System Data in the Maritime Environment |
Mar-2009 |
79 pages |
| Authors:
J M Ferebee; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| U.S. Coast Guard mission is to daily conduct law enforcement in the dynamic and challenging maritime environment. Rapid advances in technology have the potential to dramatically improve the organization's capacity to conduct this mission. The ability to track and monitor suspect vessels, as well as the law enforcement personnel that board them, is a critical next step in the evolution of Maritime Interdiction. With the development of the Global Positioning ... |
|
| Dynamic Channel Allocation in Wireless Networks Using Adaptive Learning Automata (Preprint) |
Mar-2009 |
8 pages |
| Authors:
Behdis Eslamnour; Maciej Zawodniok; S Jagannathan; MISSOURI UNIV-ROLLA DEPT OF MECHANICAL AND AEROSPACE ENGINEERING
|
| The bandwidth utilization of a single channel-based wireless networks decreases due to congestion and interference from other sources and therefore transmission on multiple channels are needed. In this paper, we propose a distributed dynamic channel allocation scheme for wireless networks using adaptive learning automata whose nodes are equipped with single radio interfaces so that a more suitable channel can be selected. The proposed scheme, Adaptive Pursuit Reward-Inaction, runs periodically on ... |
|
| Tulane/Xavier Vaccine Development/Engineering Project |
Feb-2009 |
8 pages |
| Authors:
Lucy Freytag; Vijay John; Tarun Mandal; John D Clements; TULANE UNIV NEW ORLEANS LA SCHOOL OF MEDICINE
|
| The Tulane/Xavier Biodefense Vaccine Development/Engineering project will develop new vaccines against biological threat agents to aid the war-fighter. Through the innovative use of nanotechnology, researchers and engineers from the Tulane University Schools of Medicine and Science & Engineering and the Xavier College of Pharmacy will fabricate nanoparticulate systems that are effective for transdermal and mucosal delivery of life-saving vaccines. One aim of this project will be to compare different nanocarriers ... |
|
| Extending the Conventional Information Theory: Theory and Designs of Layered Partially Decodable Codes |
29-Jan-2009 |
5 pages |
| Authors:
Lizhong Zheng; MASSACHUSETTS INST OF TECH CAMBRIDGE RESEARCH LAB OF ELECTRONICS
|
| This project is aimed at extending the conventional information theory, which is based on the idea of reliably transmitting all data bits through communication channels, by differentiating different types of data and providing different levels of error protections and thus allowing different parts of the data to be decoded at different nodes in the network. The main challenge addressed in this project is to develop new notions of partial information, ... |
|
| Distributed Optimization in an Energy-Constrained Network Using a Digital Communication Scheme |
22-Jan-2009 |
6 pages |
| Authors:
Zhi-Quan Luo; Alireza Razavi; MINNESOTA UNIV MINNEAPOLIS DEPT OF ELECTRICAL AND COMPUTER ENGINEERING
|
| We consider a distributed optimization problem where n nodes, S_I,I\in{1,...,n}), wish to minimize a common strongly convex function f(x),x=[x_1,...,x_n]T, and suppose that node S_I only has control of variable x_I. The nodes locally update their respective variables and periodically exchange their values over noisy channels. Previous studies of this problem have mainly focused on the convergence issue and the analysis of convergence rate. In this work, we focus on the ... |
|
| The Mechanosensitive Ca2+ Channel as a Central Regular of Prostate Tumor Cell Migration and Invasiveness |
Jan-2009 |
126 pages |
| Authors:
Owen P Hamill; Rosario Maroto; TEXAS UNIV MEDICAL BRANCH AT GALVESTON
|
| Our patch clamp studies indicate MscCa is expressed by the invasive prostate tumor cell PC-3. Anti-MscCa agents, Gd3+, GsmTx-4, and an anti-TRPC1 antibody block PC-3 cell migration. MscCa activity can be recorded over the surface of the PC-3 cell but is expressed at higher density on the rear compared with the front of the cell. This channel density gradient combined with a higher density of thapsigargin-sensitive Ca2+ stores in the ... |
|
| Evaluation of Output Phase Stability in a Fiber-Optic Two-Way Frequency Distribution System |
01-Dec-2008 |
9 pages |
| Authors:
Sven-Christian Ebenhag; Kenneth Jaldehag; Per Jarlemark; Per O Hedekvist; Carsten Rieck; Hakan Skoogh; SP TECHNICAL RESEARCH INST OF SWEDEN BORAS (SWEDEN)
|
| The assembly of a real-time actively controlled fiber-optic frequency transfer link based on additions to an existing static solution is proposed and evaluated. The dynamic variations of transmission delays, caused mainly by temperature dependence of the fiber, is continuously measured and used to adjust a delay at the transmitter for net cancellation of the effect. The resulting link shows no visible temperature dependence; however, the feedback induces added noise at ... |
|
| Performance Analysis of an Alternative Link-16/JTIDS Waveform Transmitted Over a Channel with Pulse-Noise Interference |
Dec-2008 |
66 pages |
| Authors:
Ho K Wei; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| The Joint Tactical Information Distribution System (JTIDS) is a hybrid frequency-hopped direct sequence spread spectrum system that utilizes a (31, 15) Reed- Solomon (RS) code and cyclical code-shift keying modulation for the data packets, where each encoded symbol consists of five bits. The primary drawback to JTIDS is the limited data rate. In this thesis, an alternative waveform consistent with the existing JTIDS waveform but with twice the data rate ... |
|
| Performance Analysis of Alternative Link-16/JTIDS Compatible Waveforms with Complex 64-Bi-Orthogonal-Keyed Modulation |
Dec-2008 |
139 pages |
| Authors:
Cheng H Kee; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| The Joint Tactical Information Distribution System (JTIDS)/Link-16 is a hybrid frequency-hopped, direct sequence spread spectrum system which is used for the exchange of real-time tactical data. The five-bit data symbols are encoded with a (31,15) Reed-Solomon (RS) code and transmitted over the channel with cyclical code-shift keying modulation. Although JTIDS/Link-16 has proven to be operationally useful, one of its primary drawbacks is its limited data rate. This thesis focuses on ... |
|
| Optimal Data Transmission on MIMO OFDM Channels |
Dec-2008 |
105 pages |
| Authors:
Luis M M Simoes; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| This thesis investigates the Physical Layer performance of single-input single-output (SISO) wireless communications systems, as well as multi antenna techniques such as multiple-input single-output (MISO) and multiple-input multiple-output (MIMO) systems, the last two utilizing the Alamouti-based space-time block coding (STBC) technique. All cases are based on the IEEE 802.16-2004 standard with OFDM using different values of coding rates. International Telecommunications Union (ITU) channel models are selected for the wireless channel ... |
|
| Gestural Communication With Accelerometer-Based Input Devices and Tactile Displays |
Dec-2008 |
8 pages |
| Authors:
Paul D Varcholik; James L Merlo; UNIVERSITY OF CENTRAL FLORIDA ORLANDO INST FOR SIMULATION AND TRAINING
|
| In this work, we introduce a communication system for common military hand and arm gestures which does not require a visual connection between the transmitter and receivers. Specifically, we present a computer mediated gesture recognition system that employs a wireless, accelerometer-based input device for collecting and classifying one- and two-hand and arm gestures. This system delivers message output through an audible channel and through a tactile display. The tactile display ... |
|
| Power Allocation Tradeoffs in Multicarrier Authentication Systems |
Dec-2008 |
9 pages |
| Authors:
P L Yu; J S Baras; B M Sadler; MARYLAND UNIV COLLEGE PARK
|
| Physical layer authentication techniques exploit signal characteristics to uniquely identify radios. We describe how multicarrier systems may use such techniques to stealthily authenticate while maintaining high levels of security and robustness. We show that with channel state information (CSI) at the transmitter and receiver, multicarrier authentication systems can further improve performance by carefully allocating the authentication power over each carrier. |
|
| Analysis Using Surface Wave Methods to Detect Shallow Manmade Tunnels |
Dec-2008 |
11 pages |
| Authors:
Niklas H Putnam; Ali Nasseri-Moghaddam; Oleg Kovin; Evgeniy Torgashov; Neil L Anderson; S Grant; MISSOURI UNIV-ROLLA DEPT OF GEOLOGY
|
| Multi-channel Rayleigh wave data were acquired across a 1 meter diameter spillway tunnel along three parallel traverses with surface to tunnel separations of 0.90 meters, 2.15 meters and 3.13 meters depth, respectively. These surface wave data were acquired by placing a 24- channel geophone array perpendicular to the center-line of the spillway tunnel and incrementally moving the array across the tunnel. The near source-receiver offset was 6 meters; the 4.5 ... |
|
| Performance Analysis of a Link-16/JTIDS Compatible Waveform Transmitted Over a Channel with Pulse-Noise Interference |
01-Sep-2008 |
110 pages |
| Authors:
Dimitrios Lekkakos; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| The Joint Tactical Information Distribution System (JTIDS) is a hybrid frequency-hoped, direct sequence spread spectrum system that utilizes a (31, 15) Reed-Solomon (RS) code and cyclical code-shift keying (CCSK) modulation for the data packets, where each encoded symbol consists of five bits. In this thesis, an alternative waveform consistent with the existing JTIDS channel waveform is analyzed. The system to be considered uses (31, 15) RS encoding as the original ... |
|
| Digital Communications Over Non-Fading and Fading Channels |
01-Sep-2008 |
95 pages |
| Authors:
Hernandez; Jose H Jr; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| The objective of this thesis is to enhance the ability of the Improved Many-on-Many (IMOM) software package to analyze modern digital communication systems using available intelligence. Currently, IMOM can only be used to analyze analog communication systems, but modern systems are, increasingly digital. In this thesis, the probability of bit error expressions for many common digital modulation techniques, both binary and non-binary, are inverted to obtain expressions for the required ... |
|
| A Conceptual Framework for Tactical Private Satellite Networks |
01-Sep-2008 |
207 pages |
| Authors:
Brian H Conrad; Ioannis Tzanos; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| The purpose of this research is three-fold. First is to examine the current state of military satellite communications and to analyze current trends in the commercial satellite communications market that support military Command and Control, as well as facilitate network operations. Second is the operational implementation of such private satellite networks within the context of Net Centric Operations, as well as within the context of a coalition environment. Third, this ... |
|
| Performance of Adaptive Coded Modulation Enabled by Long-Range Fading Prediction with Data-Aided Noise Reduction |
29-Aug-2008 |
9 pages |
| Authors:
Alexandra Duel-Hallen; Hans Hallen; Tao Jia; NORTH CAROLINA STATE UNIV AT RALEIGH OFFICE OF CONTRACTS AND GRANTS
|
| Performance of uncoded adaptive modulation (UAM) and adaptive coded modulation (ACM) enabled by the long-range prediction (LRP) that utilizes data-aided noise reduction (DANR) is investigated for rapidly varying mobile radio channels. Due to improved prediction accuracy and low pilot rate, the DANR-aided LRP outperforms previously proposed prediction methods that rely on oversampled pilots to achieve noise reduction (NR). While ACM is more sensitive to prediction errors than UAM, utilization of ... |
|
| Improved Channel Allocation for Multicarrier CDMA with Adaptive Frequency Hopping and Multiuser Detection |
29-Aug-2008 |
27 pages |
| Authors:
Alexandra Duel-Hallen; Tao Jia; NORTH CAROLINA STATE UNIV AT RALEIGH OFFICE OF CONTRACTS AND GRANTS
|
| Multicarrier code-division multiple access (MC-CDMA) system with adaptive frequency hopping (AFH) has attracted attention of researchers due to its excellent spectral efficiency. A suboptimal water-filling (WF) channel allocation algorithm was previously proposed for the reverse link of this system. To overcome the limitations of the WF algorithm in the presence of fading-induced near-far problem, a new allocation algorithm is proposed and demonstrated to improve performance when the conventional matched filter ... |
|
| Wireless Channel Modeling Based on Finite-State Markov Model |
01-Jul-2008 |
19 pages |
| Authors:
Chang-Wen Chen; FLORIDA INST OF TECH MELBOURNE
|
| The main objective of the overall proposed research was to develop a robust video communication over Airborne Networks that are operational under time varying and error prone battlefield environments with limited bandwidth and potentially transmitting/receiving with mobile and portable devices. The overall robust video communication system aiming at providing high performance video transmission under dynamic and time varying Airborne Networks will be explained in the technology background section. The objective ... |
|
| Performance Analysis of an Alternative to Trellis Coded Modulation for Waveforms Transmitted over a Channel with Pulse-Noise Interference |
01-Jun-2008 |
59 pages |
| Authors:
Monteiro; Mario R Marques; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| The performance of a communication system having almost the same spectral efficiency as a trellis coded modulation (TCM) system with r = 2/3 convolutional encoding and 8-ary phase-shift keying (8-PSK) modulation is investigated. TCM is a common solution to the problem of adding forward error correction (FEC) coding without an attendant increase in channel bandwidth. The primary drawback to TCM is that the achievable coding gain is limited by the ... |
|
| Enhanced Cyberspace Defense through Covert Publish-Subscribe Broker Pattern Communications |
01-Jun-2008 |
|
| Authors:
Steven G Paxton; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| In this thesis, we propose a novel cyberspace defense solution to the growing sophistication of threats facing networks within the Department of Defense. Current network defense strategies, including traditional intrusion detection and firewall-based perimeter defenses, are ineffective against increasingly sophisticated social engineering attacks such as spear-phishing which exploit individuals with targeted information. These asymmetric attacks are able to bypass current network defense technologies allowing adversaries extended and often unrestricted access ... |
|
| Impact of the Boundary Layer on Pointing and Tracking in Airborne Free-Space Laser Communication Links |
JUN 2008 |
120 pages |
| Authors:
Ross A. Conrad; MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF AERONAUTICS AND ASTRONAUTICS
|
| Free-space laser communication is a developing technology with enormous potential to revolutionize the way people communicate across the globe. Of specific interest are air-to-space lasercom links. Such a link experiences atmospheric scintillation, platform jitter, and boundary layer turbulence. This research investigated the tracking challenge using a focal plane array sensor with centroid and peak tracking algorithms. Also investigated was the use of a deformable mirror to recreate optical phase distortions ... |
|
| Rapid Discovery of Continuous-Performance Compounds and Powernap Compounds Through Large-Scale Mutagenesis in Drosophila |
22-Apr-2008 |
10 pages |
| Authors:
Giulio Tononi; Ruth Benca; Chiara Cirelli; WISCONSIN UNIV-MADISON BOARD OF REGENTS/RESEARCH SPONSORED PROGRAMS
|
| This Phase II proposal (G. Tononi-PI) resulted from the combination of two independent projects in Phase I: Rapid discovery of continuous performance and power-nap compounds through large-scale mutagenesis in Drosophila (G. Tononi-PI, C. Cirelli-CoPI) and Avian models of sustained wakefulness (R. Benca-PI, N. Rattenborg-CoPI). The goal of both projects was to find ways to postpone temporarily the need for sleep, and do so in a way that is completely safe. ... |
|
| A Comparison of Continuous SPD Processes for Improving the Mechanical Properties of Aluminum Alloy 6111 |
Apr-2008 |
31 pages |
| Authors:
S L Semiatin; R Lapovok; L S Toth; M Winkler; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND MANUFACTURING DIRECTORATE
|
| Microstructure evolution, mechanical properties, formability, and texture development were determined for AA6111 samples processed by asymmetric rolling (ASR) with different roll friction, velocity, or diameters, conventional rolling (CR), and equal-channel-angular pressing (ECAP). Highly elongated or sheared grain structures were developed during ASR/CR and ECAP, respectively. ASR led to improved r-values and formability compared to CR primarily as a result of the development of moderate shear-texture components analogous to those developed ... |
|
| Optimal Adaptive Transmission for a Cognitive Radio With Sensing |
Apr-2008 |
5 pages |
| Authors:
Lang Tong; Saswat Misra; Stefan Geirhofer; ARMY RESEARCH LAB ADELPHI MD
|
| We propose a randomized transmission scheme for minimizing a time-averaged cost metric in a cognitive radio. We assume that a single cognitive radio (i.e., a transmitter and receiver) hops over N orthogonal channels, each occupied by a primary user whose ON-OFF activity is modeled by a two-state Markov chain. We assume that the cognitive radio senses the activity in each channel at the beginning of every symbol period, and that ... |
|
| Applying Frequency-Domain Equalization to Code-Division Multiple Access and Transform-Domain Communications Systems |
01-Mar-2008 |
73 pages |
| Authors:
Tamayo; Alfred A III; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
|
| This research examined the theory and application of using discrete multi-tone (DMT) frequency-domain equalization (FEQ) with communications systems that inherently possess null-tones in their respective transmission frequencies. DMT-FEQ relies on null-tones to equalize a non-ideal channel. A Hadamard encoded code division multiple access (CDMA) communications system with up to 32 synchronous users and a transform domain communications system (TDCS) with one user were investigated. Both communications systems were simulated while ... |
|
| An Examination into How Group Performance is influenced by Various Communication Channels |
MAR 2008 |
49 pages |
| Authors:
Jason C. Norgaard; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
|
| This purpose of this research was to look at the how group performance is influenced by various communication channels. Specifically, this research sought to determine what communication factors are affected when groups are forced to use different communications channels. The three communications channels tested were face-to-face communications, audio conferencing, and computer-mediated communications through an Internet chat program. Each channel was measured on accuracy, efficiency, and total number of ideas generated. ... |
|
| User's Guide to STAT The SHADWELL Test Analysis Tool (Version 2.0) |
29 FEB 2008 |
34 pages |
| Authors:
John B. Hoover; NAVY TECHNOLOGY CENTER FOR SAFETY AND SURVIVABILITY WASHINGTON DC
|
| The SHADWELL Test Analysis Tool, orginally developed to aid in the analysis of large-scale fire test data, has been updated. The new version removes the dependency on proprietary, third-party software and adds support for several new data input formats, including SHADWELL LabVIEW test data and the Fire and Smoke Simulator (FSSIM) fire model output. Methods are provided for definition of data channels, selection of data based on instrument type and ... |
|
| Modeling the Transformational Communications System Urban Land Mobile Satellite Channel |
DEC 2007 |
225 pages |
| Authors:
Timothy A. Gillespie; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| The success of the Transformational Communications System depends on providing high quality communications to the mobile user in any environment. A hurdle to this success is the urban Land Mobile Satellite Channel which experiences frequent and extended deep signal fades due to shadowing by man-made structures. The problem is exacerbated for the Communications-on-the-Move channel due to use of a directional antenna. This dissertation evaluates available empirical test data, develops an ... |
|
| Acoustic Doppler Current Profiler (ADCP) Velocity Verification Experiments in the Navy's Large Cavitation Channel (LCC) |
DEC 2007 |
38 pages |
| Authors:
Dylan A. Chirchella; NAVAL SURFACE WARFARE CENTER CARDEROCK DIV BETHESDA MD
|
| The Resistance and Powering Division (Code 5200) of The Naval Surface Warfare Center, Carderock Division (NSWCCD) conducted verification experiments on a 20 degree Acoustic Doppler Current Profiler (ADCP) unit produced by RD Instruments (RDI) of San Diego, California. These experiments were conducted in the Navy's Large Cavitation Channel (LCC) located in Memphis, Tennessee. Although they have many other possible future uses, currently the ADCP units tested during this series are ... |
|
| Company and Below Command and Control Information Exchange Study |
22 OCT 2007 |
56 pages |
| Authors:
Joseph T. Coyne; Roy Stripling; Kent C. Pfluger; Zina La Budde; Daniel Afergan; NAVAL RESEARCH LAB WASHINGTON DC
|
| This report presents the results of a recently conducted task analysis on the communications needs for the Marine Corps Distributed Operations (DO) concept of infantry operations and recommendations based on currently available technologies for outfitting future DO small units. The results of this task analysis should be of use not only to DO but also to other rapidly paced collective/team-oriented operations that would benefit from distributed command and control decision ... |
|
| Polarimeter Blind Deconvolution Using Image Diversity |
SEP 2007 |
135 pages |
| Authors:
David M. Strong; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
|
| This research presents an algorithm that improves the ability to view objects using an electro-optical imaging system with at least one polarization sensitive channel in addition to the primary channel. An innovative algorithm for detection and estimation of the defocus aberration present in an image is also developed. Using a known defocus aberration, an iterative polarimeter deconvolution algorithm is developed using a generalized expectation-maximization (GEM) model. The polarimeter deconvolution algorithm ... |
|
| Signal Detection and Frame Synchronization of Multiple Wireless Networking Waveforms |
SEP 2007 |
191 pages |
| Authors:
Keith C. Howaland; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| This thesis investigates the detection, classification, frame synchronization, and demodulation of wireless networking waveforms by a digital receiver. The approach is to develop detection thresholds for wireless networking signals based upon the probability density functions of the signal present or signal absent scenarios. A Neyman-Pearson test is applied to determine decision thresholds and the associated probabilities of detection. With a chosen threshold, MATLAB simulations are run utilizing models developed to ... |
|
| Misuse Case Driven Development of Secure Information Sharing for Coalition Environment |
SEP 2007 |
82 pages |
| Authors:
Seung S. Baek; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| Sharing information among communities can result in more informed decisions being made faster. Information sharing involves the flow of unclassified and classified information, and consequently should be carefully engineered to avoid flow-based mistakes such as creating covert channels inadvertently. This thesis uses misuse cases to identify such misuses of a sharing system. We show that an appropriate distributed role-based access control model imposed upon information brokers can prevent enumerate misuse ... |
|
| Review and Synopsis of Natural and Human Controls on Fluvial Channel Processes in the Arid West |
SEP 2007 |
62 pages |
| Authors:
John J. Field; Robert W. Lichvar; ENGINEERING RESEARCH AND DEVELOPMENT CENTER HANOVER NH COLD REGIONS RESEARCH AND ENGINEERING LAB
|
| Parallel to ongoing efforts to revise the U.S. Army Corps of Engineers wetland delineation manual for support of Section 404 under the Clean Water Act, the Corps has initiated an effort to develop an "Ordinary High Water" (OHW) delineation manual. The Arid West region is dominated by watersheds with intermittent and ephemeral dry washes. Consequently, many aquatic resources lack the three characteristic features of a wetland, but they still perform ... |
|
| Fluvial Instability and Channel Degradation of Amite River and its Tributaries, Southwest Mississippi and Southeast Louisiana |
SEP 2007 |
126 pages |
| Authors:
Ryan Hood; David M. Patrick; Maureen K. Corcoran; ENGINEER RESEARCH AND DEVELOPMENT CENTER VICKSBURG MS GEOTECHNICAL AND STRUCTURES LAB
|
| Abstract: The Amite River is a Gulf Coastal Plain stream in southwestern Mississippi and eastern Louisiana. Since the early 1970s, riparian sand and gravel mining has been conducted on a 48-km reach of the river centered on Grangeville, LA. Riparian mining has been considered responsible for instability and changes in the hydraulic and geomorphic regime of the river and local extirpation of the inflated heelsplitter mussel. Field and rotary-wing aerial ... |
|
| A Planar Hall Thruster for Investigating Electron Mobility in ExB Devices (Preprint) |
24 AUG 2007 |
13 pages |
| Authors:
Joshua L. Rovey; Matthew P. Giacomi; Robert A. Stubbers; Brian E. Jurczyk; STARFIRE INDUSTRIES LLC CHAMPAIGN IL
|
| Stable operation of a Hall thruster that emits and collects the Hall current across a planar discharge channel is described. The planar Hall thruster (PHT) is being investigated for use as a test bed to study electron mobility in ExB devices. The planar geometry attempts to de-couple the complex electron motion found in annular thrusters by using simplified geometry. During this initial test, the PHT was operated at discharge voltages ... |
|
| Adaptive Transceivers for Wireless Spectrum Networks |
21 AUG 2007 |
18 pages |
| Authors:
Michael L. Honig; NORTHWESTERN UNIV EVANSTON IL OFFICE OF RESEARCH SPONSORED PROJECTS
|
| This project has been concerned with joint transmitter-receiver adaptation in a distributed, peer-to-peer wireless network. Parameters that can be adapted at the transmitter include rate, power, and signatures in space-time-frequency. In this report we summarize our work on the following topics: (1) Limited feedback schemes for optimizing spatial signatures for Multi-Input Multi-Output (MIMO) channels, and power and rates for multi-carrier transmission; (2) Optimization of training overhead for MIMO block fading ... |
|
Reports by Keyword(s)
CHANNELS
