Relating the behavior of predators to prey density is an important aspect of foraging theory. Changes in prey accessibility may have contributed to a greater-than 80% decline in Steller sea lions (Eumetopias jubatus) throughout the western portion of their range during the last 30 years. A new method was developed for inferring prey accessibility to juveniles of this otariid, from observable features of diving and ranging behavior. Seventeen juveniles (9F, 8M) were monitored in multiple seasons and locations in the Gulf of Alaska via satellite telemetry. Twelve of the 17 had experienced 1-3 months of temporary captivity. Effects of temporary captivity on endurance, habitat use and development of diving and ranging behavior were tested. Diving and ranging patterns of previously captive juveniles were consistent with data reported for freeranging juveniles. Development in mean dive depth and duration after release was likely due to increased foraging. "Focus in time spent at depth" was tested as a proxy for prey accessibility using predictions based on foraging theory. 'Focus...' was defined as vertical concentration in dive distribution and was calculated by comparing the observed time spent at depth with an expected distribution. There was significantly more focus in summer than winter, and more focus at depth (>62 m) in winter. Focus at depth was significantly greater during midday for juveniles monitored in winter. Significant negative correlation between maximum focus and trip duration provided the best indication that focus may be related to prey accessibility. Short trips had significantly greater maximum focus than long trips, using a matched-pairs approach. Analysis of focus in time-at-depth data can elucidate small scale interactions between juvenile otariids and their prey. This new method of measuring the dive behavior of otariids can be applied to individual foraging trips and holds promise as a proxy for assessing seasonal, annual and developmental changes in individual prey accessibility.

Localization is very important for self-organizing wireless networks. The localization process involves two main steps: ranging, i.e., estimating the distance between an unlocalized node and the anchor nodes within its range, and the localization algorithm to compute the location of the unlocalized nodes using the anchor coordinates and the estimated ranges. To be able to estimate the distance, the receiver needs to detect the arrival time of the received signals precisely. Thus, the first part of this research is related to time synchronization. We propose two new symbol timing offset estimation (STO) algorithms that can detect the start of an orthogonal frequency division multiplexing (OFDM) symbol more accurately than others in a Rayleigh fading channel. OFDM is used to perform timing synchronization because it is incorporated inmany current and future wireless systems such as 802.11, WiMAX, wireless USB, and WiMedia. The first proposed algorithm uses a metric that is calculated recursively. Two estimation methods are considered: one using the average of the metric results, and the other using the median. The second approach uses a preamble designed to have a maximum timing metric for the correct location and very small values otherwise. These algorithms are shown to outperform recent algorithms in the literature. In the second part of this dissertation we explore the second step of the localization problem. There are two kinds of localization: range-free and range-based. A new distributed range-free localization algorithm is proposed where every unlocalized node forms two sets of anchors. The first set contains one-hop anchors from the unlocalized node. The second set contains two-hop and three-hop anchors away from the unlocalized node. Each unlocalized node uses the intersections between the ranging radii of these anchors to estimate its position. Four different range-based localization algorithms are proposed. These algorithms use techniques from data mining to process the intersection points between an unlocalized node and nearby anchors. The first proposed scheme is based on decision tree classification to select a group of intersection points. The second is based on the decision tree classification and K-means clustering algorithms applied to the selected intersection points by the decision trees. The third is based on decision tree classification and the density-based spatial clustering of applications with noise (DBSCAN) algorithm applied to the intersection points selected by decision trees. The last approach uses the density-based outlier detection (DBOD) algorithm. DBOD assigns density values to each point being used in the location estimation. The mean of these densities is calculated and those points having a density larger than the mean are kept as candidate points. These proposed approaches are shown to outperform recent algorithms in the literature. / Graduate

A method for estimating distance, in one dimension, to a transmitter for a receiver in motion relative to that transmitter is given with simulation data. The method relies on a stateful preprocessor filter and does not require envelopment of the transmitter.

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In this thesis a UWB-based ranging scheme is designed, simulated, implemented and tested. This system was designed to address the problem of safely unloading cargo crates to ships in the open seas. UWB antennas are placed on the four corners of the cargo crate, providing the information needed to a ranging/positioning algorithm that estimates the orientation and distance of the ship's deck from the crate. Furthermore, the system is successfully tested in a 1/24 scale demonstration. In addition to the UWB ranging application, this thesis evaluates an already proposed modification to the traditional narrowband link budget based on the Friis transmission formula. The proposed modification replaces frequency-domain parameters with time-domain values to handle the wide bandwidth of UWB systems. The proposed approach is shown via measurements to be much more accurate than the traditional technique. / Master of Science

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ACCURATE ACOUSTIC RANGING SYSTEM USING ANDROID SMARTPHONES By Mohammadbagher Fotouhi, Master of Science A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science at Virginia Commonwealth University Virginia Commonwealth University 2017 Major Director: Dr. Ruixin Niu, Associate Professor of Department of Electrical and Computer Engineering In this thesis, we present the design, implementation, and evaluation of an android ranging system, a high-accuracy acoustic-based ranging system which allows two android mobile phones to learn their physical distance from each other. In this system we propose a practical solution for accurate ranging based on acoustic communication between speakers and microphones on two smartphones. Using the audible-band acoustic signal with the Wi-Fi assistance without the sound disturbance is promising for large deployment. Our method is a pure software-based solution and uses only the most basic set of commodity hardware: a speaker, a microphone, and Wi-Fi communication. So it is readily applicable to many commercial-off-the-shelf mobile devices like cell phones. Our system is the result of several design goals, including user privacy, decentralized administration, and low cost. Rather than relying on any centralized management which tracks the user’s location to help them find their distance, our system helps devices learn their distance from each other without advertising their location information with any centralized management. Compared to alternatives that require special-purpose hardware or pre-existence of precision location infrastructure , our system is applicable on most of off-the-shelf components so it is a commodity-based solution will obviously have wider applications and is cost effective. Currently, two smartphones are used to estimate the distance between them through Wi-Fi and audio communications. The basic idea is estimating the distance between two phones by estimating the traveling time of audio signal from one phone to the other as the speed of sound is known. The preliminary results of ranging demonstrate that our algorithm could achieve high accuracy, and stable and reliable results for real time smartphone-based indoor ranging.

International Telemetering Conference Proceedings / October 22-25, 2001 / Riviera Hotel and Convention Center, Las Vegas, Nevada / In response to a NASDA decision to upgrade their satellite ground network (GN) to provide worldwide coverage as well as interoperability with other agencies, MELCO has assembled remote ground stations that include the L-3 Communications Telemetry & Instrumentation (L-3 T&I) NETstar 20001 TT&C system. Software developed by Mitsubishi Electric Corporation (MELCO) controls a variety of COTS products in the remote stations, including the L-3 T&I system. L-3 T&I’s TT&C system provides modem services, high accuracy ranging, Doppler compensation, command verification, and CCSDS protocol processing for a wide range of LEO/MEO/GEO satellites.

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Since March 2006 the Institute of Meteorology in Leipzig (LIM) is owner of a commercial Mini-SODAR. The Mini-SODAR is very small in size and therefore mobile. It can be set up with low effort in short time at any place. The first testmeasurement was operated in June 2006 at the boundary layer field site Falkenberg that belongs to the Meteorological Observatory Lindenberg (MOL) of the German Meteorological Service (DWD) and was parallel accompanied by the measurement of a windtower and a Doppler-SODAR. The results of this six-hour-measurement are presented here. A statistical comparison between Mini-SODAR, tower data and Doppler-SODAR was performed. Also backscatter intensity and profile data from Mini-SODAR were analysed and interpreted. / Seit März 2006 ist das Leipziger Institut für Meteorologie (LIM) in Besitz eines kommerziellen Mini-SODARs. Das Mini-SODAR ist auf Grund seiner Größe sehr mobil und lässt sich unter geringem Aufwand schnell an einem beliebigen Standort aufbauen. Die erste größere Testmessung und gleichzeitig Vergleichsmessung dieses Gerätes mit einem Windmast und einem Doppler-SODAR fand im Juni 2006 auf dem Grenzschichtmessfeld in Falkenberg statt, welches zum Meteorologischen Observatorium (MOL) des Deutschen Wetterdienstes (DWD) gehört. Die Auswertung dieser 6-stündigen Messung wird hier vorgestellt. Es wurde ein statistischer Vergleich zwischen Mini-SODAR, Windmast und Doppler-SODAR durchgeführt. Weiterhin wurden das Sodargramm und die gemessenen Profildaten des Mini-SODARs untersucht und interpretiert.