A5050353111- Millimeter-Wave Propagation and Modeling
- Advanced MIMO Systems Optimization
- Power Line Communications and Noise
- Planetary Science and Exploration
- Ultra-Wideband Communications Technology
- Indoor and Outdoor Localization Technologies
- Wireless Communication Networks Research
- Fluid Dynamics and Turbulent Flows
- Radio Wave Propagation Studies
- Advanced Wireless Communication Techniques
- Antenna Design and Analysis
- Microwave Engineering and Waveguides
- Vehicular Ad Hoc Networks (VANETs)
- Space Satellite Systems and Control
- Precipitation Measurement and Analysis
- Astro and Planetary Science
- Computational Fluid Dynamics and Aerodynamics
- Bluetooth and Wireless Communication Technologies
- Fluid Dynamics and Vibration Analysis
- Wireless Body Area Networks
- Satellite Communication Systems
- Microwave Imaging and Scattering Analysis
- Quantum and electron transport phenomena
- Cognitive Radio Networks and Spectrum Sensing
- Advanced Adaptive Filtering Techniques
Institute for Telecommunication Sciences
2024
National Telecommunications and Information Administration
2023-2024
United States Naval Academy
2014-2023
University of Manchester
2023
Mathematical Sciences Research Institute
2022
Simon Fraser University
2021
Virginia Tech
2002-2020
United States Naval Research Laboratory
2015
United States Navy
2011
University of California, Los Angeles
1993-2010
Contributions to understanding organization-environment interaction from the policy and organization areas are integrated through a perceptual model of strategy formulation. Key inputs in model...
This paper contains measured data and empirical models for 2.5 & 60 GHz in-building propagation path loss multipath delay spread.Path measurements were recorded using a broadband sliding correlator channel sounder which over 39,000 Power Delay Profiles (PDPs) in 22 separate locations modern office building.Transmitters receivers separated by distances ranging from 3.5 to 27.4 meters, variety of obstructions, order create realistic environments future single-cell-per-room wireless...
We give error estimates for fully discretized two- and three-dimensional vortex methods introduce a new wy of evaluating the stretching vorticity in methods. The convergence theory Beale Majda is discussed simple proof Cottet's consistency result presented. also describe how to obtain accurate two-dimensional which initial computational points are distributed on nodes nonrectangular grids, compare several
Previous work has shown that UWB systems can be used for remote vital-signs monitoring, with the major applications of these being in health monitoring and rescue scenarios. In this paper, we demonstrate use impulse-based signals robust detection chest-cavity motion accurate estimation respiration heart-beat rates, even presence physical obstructions between subject antennas. The main contribution paper is an analytical framework development signal processing algorithms to estimate heart...
Near-ground radio-wave propagation is of interest for emerging military applications such as battlefield sensor networks and wireless communication between dismounted soldiers. Narrowband wideband channel measurement results at 300 1900 MHz are presented near-ground propagation, characterising the effect antenna heights, radiation patterns foliage environments. An additional set measurements was performed to study rain on in a forest environment. Measured power–delay profiles indicate...
Results of a test managerial response to environmentally induced stress indicated that locus control was highly related perception in- the environment and use decision or ...
Broadband access is key to ensuring robust economic development and improving quality of life. Unfortunately, the communication infrastructure deployed in rural areas throughout world lags behind its urban counterparts due low population density economics. This article examines motivations challenges providing broadband over vast regions, with an emphasis on wireless aspect view irreplaceable role closing digital gap. Applications opportunities for future communications are discussed a...
The wireless spectrum is a natural resource upon which we all depend in more ways than realize. While our personal and professional lives thrive on mobile broadband, plethora of other applications, such as weather forecasting, climate science, astronomy, space exploration, civil/military navigation also critically the radio spectrum. Although these technologies are vastly different, they share common need for increasingly converge to same bands. Currently, technological policy frameworks...
On-frequency repeaters provide network operators with a cost-effective means of extending coverage to areas low signal strength. Their ability transmit and receive on the same channel essentially renders their operation transparent rest network. The maximum gain an on-frequency repeater is, however, limited by amount isolation that exists between transmitter receiver antennas. Adaptive cancellation techniques may be used mitigate lack isolation, but performance is track time-varying...
This paper is a step toward defining the characteristics of suitable antenna to exploit inherent advantages in pulsed communication systems, specifically that ultra-wideband. In this respect, several traditional broadband architectures are evaluated with an emphasis given towards time-domain perspective. addition, good UWB should be reasonably efficient over entire frequency band allocated by Federal Communications Commission (FCC) enable operators employ different systems without having use...
The IEEE Standard 754-1985 for binary floating-point arithmetic [19] was revised [20], and an important addition is the definition of decimal [8], [24]. This intended mainly to provide a robust reliable framework financial applications that are often subject legal requirements concerning rounding precision results, because may introduce small but unacceptable errors. Using calculations emulate in order correct this issue has led existence numerous proprietary software packages, each with its...
Radio tomographic imaging (RTI) has recently been proposed for tracking object location via radio waves without requiring the objects to transmit or receive signals. The position is extracted by inferring which voxels are obstructing a subset of links in dense wireless sensor network. This paper proposes variety modeling and algorithmic improvements RTI scenario roadside surveillance. These include use more physically motivated weight matrix, method mitigating negative (aphysical) data due...
Magnetoreception has been demonstrated in all five vertebrate classes. In rodents, nest building experiments have shown the use of magnetic cues by two families molerats, Siberian hamsters and C57BL/6 mice. However, assays widely used to study rodent spatial cognition (e.g. water maze, radial arm maze) failed provide evidence for cues. Here we show that mice can learn direction a submerged platform 4-armed (plus) maze. Naïve were given brief training trials. each trial, mouse was confined...
Software-defined radio is a rapidly developing field that driving the development of and innovation in communications technology, promises to significantly impact all sectors. Entities these SDR systems require trained workforce has been prepared with mindset, knowledge, skills, tools required address both system (breadth) technical (depth) aspects systems. Developing SDRs necessarily involves collection disciplines including, but not limited to, electromagnetics, radio-frequency...
This paper contains measured data for 2.5 and 60 GHz in-building partition loss. Path loss measurements were recorded using a broadband sliding correlator channel sounder which over 39000 power delay profiles (PDP) in 22 separate locations modern office building. Transmitters receivers separated by distances ranging from 3.5 to 27.4 meters, variety of obstructions, order emulate future single-cell-per-room wireless networks. These may aid the development networks unlicensed 2.4 bands.
This paper presents a pioneering study based on series of experiments the operation commercial Time-Division Long-Term Evolution (TD-LTE) systems in presence pulsed interfering signals 3550-3650 MHz band. TD-LTE operations were carried out channels overlapping and adjacent to high power SPN-43 radar with various frequency offsets between two evaluate susceptibility LTE signal. Our results demonstrate that communication using low antenna heights was not adversely affected by signal operating...
The goal of this article is to investigate the propagation behavior 28-GHz millimeter wave in coniferous forests and model its basic transmission loss. Field measurements were conducted with a custom-designed sliding correlator sounder. Relevant foliage regions extracted from high-resolution LiDAR data satellite images. Our results show that traditional analysis models for lower-frequency wireless communications fail consistently output correct path loss predictions. Novel fully automated...
Wideband measurements were performed using a direct-sequence spread-spectrum measurement system in the air-to-ground radio environment to characterize propagation between an airborne transmitter and ground-based receiving antenna array at center frequency of 2.05 GHz. The was flown along constant-radius arcs low altitudes around receiver location obtain results for 7.5, 15, 22.5, 30 degree elevation angles. An 80 megachip per second (Mcps) modulating PN sequence transmitted by station....
Impulse ultrawideband (UWB) communication promises a number of benefits for use in wireless sensor networks, particularly forest environments, where it has the potential to provide robust operation, along with ability combine communications precision position location. In this paper, we present measurement results and empirical models UWB signal propagation environment. Path-loss measurements were performed using 620-ps duration pulse frequency range 830-4200 MHz. More than 22 000 recorded...
A global optimization technique is applied to solve the optimal transmitter placement problem for indoor wireless systems. An efficient pattern search algorithm - DIviding RECTangles (DIRECT) of Jones et al.- has been connected a parallel three-dimensional radio propagation ray tracing modeler running on 200-node Beowulf cluster Linux workstations. Surrogate functions wideband code-division multiple-access (WCDMA) simulator were used estimate system performance algorithm. Power coverage and...
Vital-signs monitoring devices continue to utilize invasive sensing methodologies, ranging from skin surface contact techniques such as the use of electrodes for measuring cardiac signals (ECG test), more intrusive utilization a facial mask gas exchange during respiration. In this paper, we present wireless radar technique based on ultra-wideband (UWB) technology non-invasive heart and respiration rates. Our is detection chest-cavity motion through measurement UWB signal displacements due...