14 results on '"Sherwood W. Samn"'
Search Results
2. Radar and Sonar Sensor Networks
- Author
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Qilian Liang, Xiuzhen Cheng, Scott. C.-H. Huang, Sherwood W. Samn, Lingming Wang, and Zheng Zhou
- Subjects
Telecommunication ,TK5101-6720 ,Electronics ,TK7800-8360 - Published
- 2010
- Full Text
- View/download PDF
3. A Propagation Environment Modeling in Foliage
- Author
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Sherwood W. Samn, Jing Liang, and Qilian Liang
- Subjects
Telecommunication ,TK5101-6720 ,Electronics ,TK7800-8360 - Abstract
Foliage clutter, which can be very large and mask targets in backscattered signals, is a crucial factor that degrades the performance of target detection, tracking, and recognition. Previous literature has intensively investigated land clutter and sea clutter, whereas foliage clutter is still an open-research area. In this paper, we propose that foliage clutter should be more accurately described by a log-logistic model. On a basis of pragmatic data collected by ultra-wideband (UWB) radars, we analyze two different datasets by means of maximum likelihood (ML) parameter estimation as well as the root mean square error (RMSE) performance. We not only investigate log-logistic model, but also compare it with other popular clutter models, namely, log-normal, Weibull, and Nakagami. It shows that the log-logistic model achieves the smallest standard deviation (STD) error in parameter estimation, as well as the best goodness-of-fit and smallest RMSE for both poor and good foliage clutter signals.
- Published
- 2010
- Full Text
- View/download PDF
4. Guest Editorial Special Issue on Internet of Mission-Critical Things (IoMCT)
- Author
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Jing Liang, Sherwood W. Samn, Qilian Liang, Tariq S. Durrani, Xin Wang, and Jinhwan Koh
- Subjects
Focus (computing) ,Computer Networks and Communications ,Computer science ,business.industry ,Mission critical ,Control (management) ,Computer security ,computer.software_genre ,Computer Science Applications ,Hardware and Architecture ,Order (business) ,Signal Processing ,Bandwidth (computing) ,The Internet ,Adaptation (computer science) ,business ,Internet of Things ,computer ,Information Systems - Abstract
Internet of Things is coming to critical missions such as battlefield, border patrol, search and rescue, critical structure monitoring and surveillance, etc. Internet of Things (IoT) in Critical Missions or Internet of Mission-Critical Things (IoMCT) is propelled by the convergence of sensing, communication, computing, and control. To support IoMCT, the mission-critical networks will need to be flexible and interactive, and still work despite limited bandwidth, intermittent connectivity and with a large number of devices on the network. The focus of IoMCT is to improve surveillance utilizing a network, not fusion of disparate sensor products. Such adaptation, management, and re-organization of information sources, devices, and networks must be accomplished almost entirely autonomously, in order to avoid imposing additional burdens on the humans, and without much reliance on support and maintenance services.
- Published
- 2018
5. Signal processing for heterogeneous sensor networks
- Author
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Yiming Pi, Qilian Liang, Tariq S. Durrani, and Sherwood W. Samn
- Subjects
Signal processing ,Computer science ,010401 analytical chemistry ,Real-time computing ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Key distribution in wireless sensor networks ,Control and Systems Engineering ,Sensor node ,Signal Processing ,Computer Vision and Pattern Recognition ,Electrical and Electronic Engineering ,0210 nano-technology ,Wireless sensor network ,Software - Published
- 2016
6. Hybrid Wireless Sensor Networks: Theory and Design
- Author
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Tariq S. Durrani, Sherwood W. Samn, Yiming Pi, and Qilian Liang
- Subjects
Wi-Fi array ,Article Subject ,Computer Networks and Communications ,Computer science ,business.industry ,Wireless network ,General Engineering ,lcsh:QA75.5-76.95 ,Key distribution in wireless sensor networks ,Mobile wireless sensor network ,lcsh:Electronic computers. Computer science ,business ,Wireless sensor network ,Computer network - Published
- 2016
- Full Text
- View/download PDF
7. NEW: Network-Enabled Electronic Warfare for Target Recognition
- Author
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Xiuzhen Cheng, Sherwood W. Samn, and Qilian Liang
- Subjects
Engineering ,Electronic warfare support measures ,business.industry ,Doppler radar ,Aerospace Engineering ,law.invention ,Diversity combining ,Automatic target recognition ,law ,Electronic engineering ,Waveform ,Electrical and Electronic Engineering ,Radar ,Electronic warfare ,business ,Wireless sensor network - Abstract
Network-enabled electronic warfare (NEW) is the development of modeling and simulation efforts that explore the advantages and limitations of NEW concepts. The advantages of linking multiple electronic support measures (ESM) and electronic attack (EA) assets to achieve improved capabilities across a networked battle force have yet to be quantified. In this paper, we utilize radar sensors as ESM and EA assets to demonstrate the advantages of NEW in collaborative automatic target recognition (CATR). Signal (waveform) design for radar sensor networks (RSN) in NEW is studied theoretically. The conditions for waveform coexistence and the interferences among waveforms in RSN are analyzed. We apply the NEW to CATR via waveform diversity combining and propose maximum-likelihood (ML)-ATR algorithms for nonfluctuating targets as well as fluctuating targets. Simulation results indicate that our NEW-CATR performs much better than the single sensor-based ATR algorithm for nonfluctuating and fluctuating targets.
- Published
- 2010
8. UAV-based passive geolocation based on channel estimation
- Author
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Qilian Liang and Sherwood W. Samn
- Subjects
Computer science ,business.industry ,Transmitter ,Radio receiver ,Multilateration ,law.invention ,Geolocation ,Signal-to-noise ratio ,law ,Rician fading ,Embedded system ,FDOA ,Wireless ,Fading ,business ,Algorithm ,Communication channel - Abstract
In this paper, we propose a Time Difference of Arrival (TDoA) algorithm for passive geolocation based on delay estimation of two correlated wireless channels. It's assumed that the passive receiver is carried by a small flying UAV in the sky, and the transmitter is located on the ground (static or mobile), so Rician flat fading model should be used. To estimate the delay of two correlated channels, Block Phase Estimation (BPE) is used for each wireless channel estimation, and then the two estimated channels are compared to get the best time delay. We also compare it against a cross-correlation-based TDoA algorithm. Simulation results show that our TDoA algorithm performs much better than the cross-correlation-based TDoA algorithm with a lower level of magnitude in terms of average TDoA error and Root-Mean-Square-Error (RMSE). Four different Rician fading channel groups are evaluated, and conclusions are drawn for our TDoA algorithm and the cross-correlation-based TDoA algorithm.
- Published
- 2010
9. Radar and Sonar Sensor Networks
- Author
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Lingming Wang, Zheng Zhou, Xiuzhen Cheng, Qilian Liang, Scott C.-H. Huang, and Sherwood W. Samn
- Subjects
Computer Networks and Communications ,Computer science ,business.industry ,lcsh:Electronics ,lcsh:TK7800-8360 ,Archaeology ,lcsh:Telecommunication ,Computer Science Applications ,law.invention ,Beijing ,law ,lcsh:TK5101-6720 ,George (robot) ,Signal Processing ,Sonar sensor ,Radar ,Telecommunications ,business - Abstract
1Department of Electrical Engineering, University of Texas at Arlington, Arlington, TX 76019-0016, USA 2Department of Computer Science, The George Washington University, Washington, DC 20052, USA 3Department of Electrical Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan 4Air Force Research Laboratory/RHX, Brooks City Base, San Antonio, TX 78235, USA 5Core Software Department, iBiquity Digital Corporation, 150 Allen Road, Suite 201, Basking Ridge, NJ 07920, USA 6School of Information and Telecommunications, Beijing University of Posts and Telecommunications, Beijing 100876, China
- Published
- 2010
10. Sense-Through-Wall Channel Modeling Using UWB Noise Radar
- Author
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Jing Liang, Sherwood W. Samn, Ram M. Narayanan, and Qilian Liang
- Subjects
Signal processing ,Computer science ,Noise (signal processing) ,business.industry ,Delay spread ,Time of arrival ,Amplitude ,Radar imaging ,Telecommunications ,business ,Algorithm ,Multipath propagation ,Impulse response ,Computer Science::Information Theory ,Communication channel - Abstract
Sensing-through-wall will benefit various applica- tions such as emergence rescues and military operations. In order to add more signal processing functionality, it is vital to understand the characterization of sense-through-wall channel. In this paper, we propose a statistical channel model on a basis of real experimental data using UWB noise radar. We employ CLEAN algorithm to obtain the multipath channel impulse response (CIR) and observe that the channel amplitude at each path can be accurately characterized as T location-scale distribution. We also analyze that the multipath contributions arrive at the receiver are grouped into clusters. The time of arrival of clusters can be modeled as a Poisson arrival process, while within each cluster, subsequent multipath contributions or rays also arrive according to a Poisson process. However, these arrival rates are much smaller than those of indoor UWB channels.
- Published
- 2009
11. UWB Radar Sensor Networks for Sense-Through-Foliage Target Detection
- Author
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Sherwood W. Samn, Xiuzhen Cheng, and Qilian Liang
- Subjects
Ideal (set theory) ,business.industry ,Computer science ,Rake ,Object detection ,Ultra wideband radar ,Image (mathematics) ,Radar imaging ,Discrete cosine transform ,Computer vision ,Artificial intelligence ,Hardware_ARITHMETICANDLOGICSTRUCTURES ,business ,Telecommunications - Abstract
In this paper, we propose a discrete-cosine-transform (DCT)-based approach for sense-through-foliage target detection when the echo signal quality is good, and a radar sensor network (RSN) and DCT-based approach when the echo signal quality is poor. A RAKE structure which can combine the echos from different cluster-members is proposed for clusterhead in the RSN. We compared our approach with the ideal case when both echos are available, i.e., echos with target and without target. We also compared our approach against the scheme in which 2-D image was created via adding voltages with the appropriate time offset. Simulation results show that our DCT-based scheme works much better than the existing approach, and our RSN and DCT-based approach can be used for target detection successfully while even the ideal case fails to do it.
- Published
- 2008
12. Foliage Clutter Modeling Using the UWB Radar
- Author
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Sherwood W. Samn, Jing Liang, and Qilian Liang
- Subjects
Mean squared error ,Computer science ,law ,Estimation theory ,Statistics ,Clutter ,Statistical model ,Nakagami distribution ,Radar ,Ultra wideband radar ,Standard deviation ,Constant false alarm rate ,law.invention - Abstract
In this paper, we propose that the foliage clutter follows log-logistic model using maximum likelihood (ML) parameter estimation as well as the root mean square error (RMSE) on PDF curves between original clutter and statistical model data. The measured clutter data is provided by Air Force Office of Scientific Research (AFOSR). In addition to investigating the log-logistic model, we also compare it with other popular clutter models, namely log-normal, Weibull and Nakagami. We show that the log-logistic model not only achieves the smallest standard deviation (STD) error on estimated model parameters, but also has the best goodness-of-fit and smallest RMSE. Further, the performance of detection at presence of foliage clutter is theoretically analyzed.
- Published
- 2008
13. NEW-CATR: Network-enabled Electronic Warfare for Collaborative Automatic Target Recognition
- Author
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Qilian Liang and Sherwood W. Samn
- Subjects
Engineering ,Electronic warfare support measures ,business.industry ,Real-time computing ,law.invention ,Modeling and simulation ,Diversity combining ,Automatic target recognition ,Intelligent sensor ,law ,Electronic engineering ,Electronic warfare ,Radar ,business ,Diversity scheme - Abstract
Network-enabled Electronic Warfare (NEW) is to develop modeling and simulation efforts to explore the advantages and limitations of network-enabled electronic warfare concepts. The advantages of linking multiple electronic support measures (ESM) and electronic attack (EA) assets to achieve improved capabilities across a networked battleforce have yet to be quantified. In this paper, we will use radar sensors as ESM and EA assets to demonstrate the advantages of NEW in Collaborative Automatic Target Recognition (CATR). We apply the NEW to CATR via waveform diversity combining and and propose maximum-likehood (ML)-ATR algorithms for nonfluctuating target as well as fluctuating target. Simulation results show that our NEW-CATR performs much better than single sensor-based ATR algorithm for nonfluctuating targets or fluctuating targets. Conclusions are drawn based on our analysis and simulations and future research works on this research topic are discussed.
- Published
- 2007
14. Mathematical Modeling of the Temperature Rise in a Thin Cell Culture Exposed to High Frequency Electromagnetic Irradiation
- Author
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Sherwood W. Samn
- Subjects
Physics ,Optics ,Mathematical model ,Infrared ,business.industry ,Finite-difference time-domain method ,Extrapolation ,Time domain ,Irradiation ,Absorption (electromagnetic radiation) ,business ,Electromagnetic radiation ,Computational physics - Abstract
This report describes a mathematical model to predict the temperature increase in a thin layer of tissue culture exposed to electromagnetic energy at a frequency of 35 gigahertz (GHz). The goal of the modeling effort was to compare the calculated temperature rise with experimental valves obtained with mouse microphage cell cultures using an infrared camera. The expected temperature increase was calculated using a commercial finite difference time domain code (FDTD). Two problems arise when using FDTD to simulate high frequency electromagnetic radiation of a thin culture to obtain temperature information important to biologists: small time step (necessitating long simulation time) and extrapolation of temperature from specific absorption rates (SARs). In this paper we describe our numerical calculations and compare their results with experimental observations.
- Published
- 2003
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