No description available.

No description available.

This report presents an initial design effort for a high-speed, constant Frequency data extractor, which can be used to identify and track a particular constant frequency signal in the presence of other signals. Several factors must be included in the design considerations. The detection and acquisition of the correct signal should be accomplished at high speed to remain as close as possible to real time. Once detection has occurred, the system should generate a track-predict gate signal that enables the input line only when the real input pulse is expected. If track is lost, which happens whenever the track-predict gate and input pulse do not occur simultaneously, the initial detection method must be re-entered. The detectable frequency should be selectable over a wide range of values. Furthermore, the system should be able to detect and acquire the desired signal in the presence of large numbers of interfering signals, yet be flexible enough to adapt easily to other pulse modulation methods. Because of the above design factors as well as speed, size, and cost, a high-speed bipolar microprocessor was selected for this system implementation. A microprocessor allows most of the detection and acquisition to be accomplished in the software, thus making the system very adaptable to the host system's requirements.

We develop a general three-stage Moving Average Matched Filter (MAMF) receiver system for digital communications in an environment where the noise conditions are unknown a priori and change constantly and significantly with time. The MAMF is a subset of the class of matched filters which are optimal with respect to enhancing the signal energy relative to the noise power in order to improve discrimination between signals at the receiver. In a time-varying noise environment, a fixed signal cannot be designed and used for transmission which will provide optimal performance at the receiver under all noise conditions. Designing a signal for optimality in a particular noise environment will typically lead to a deteriorated performance in another noise environment relative to a signal which is chosen for the new environment. This deterioration in performance can be so severe that the signal-to-noise ratio (SNR) from the input to the output of the filter is degraded. Ideally, to achieve performance which is more nearly optimal under all noise conditions, the transmitted signal should change or adapt in response to variations in the noise environment. For practical reasons, it is desirable to concentrate all adaptivity in the receiver rather than the transmitter. Typically, a MAMF receiver consists of two stages - a filtering stage and a detection stage. We develop the general design expressions for a three-stage MAMF receiver in which the additional stage is a linear pre-filter placed before the filtering and detection stages. Obviously, if the MAMF is optimal for a given noise condition, any operation performed on the received signal plus noise prior to filtering will potentially reduce performance at that given noise condition by some amount. We accept this performance loss in favor of a pre-filtering operation which can effectively manipulate the transmitted signal upon arrival at the receiver and provide more robust performance in the time-varying noise environment. Specifically, we compare a pre-filter consisting of a unity gain with a prefilter that linearly combines k M x 1 partitions of the transmitted signal vector (i.e. transmitted signal vector of length N = k x M). Proper design of the transmitted signals can ensure that the partitions are linearly independent. In this case, we can view the transmitted signal as representing a k-dimensional subspace of the original M-dimensional signal space. By linearly combining these partitions at the receiver we can achieve any vector within this subspace. We show that we can select these partitions such that the resulting signal vector represents an optimum signal subspace for k noise environments. This is contrasted with the fixed 1-dimensional subspace of the original N-dimensional signal subspace when the pre-filter is a constant gain. The two MAMF receivers are compared by measuring the signal-to-noise ratio improvement (SNRI) of the filters. The SNRI is defined as the output signal-to-noise ratio (OSNR) measured at the output of the filtering stage over the input signal-to-noise ratio (ISNR) measured at the input to the pre-filtering stage. We demonstrate through simulation that the signal subspace version can be more robust with respect to deviation from the absolute maximum SNRI achievable by either system. Using maximum likelihood techniques, we derive an optimal detector for an arbitrary bank of L linear pre-filter and MAMF sections. This is shown to outperform a detection scheme that has been derived for use solely in an optimal binary communication scenario. / Master of Science

Submitted in fulfillment of the academic requirements for the Degree Master of Engineering: Electrical: Electronic Engineering, Durban University of Technology. Durban. South Africa, 2015. / A two element correlating radio telescope interferometer is the fundamental building block of modern radio telescope aperture synthesis arrays. Early radio telescopes consisted of a single antenna, usually a dish antenna. Larger and larger antennas were constructed in order to improve the resolution of the measurement of the direction and extent of radio frequency radiation coming from the sky. Telescope resolution is fundamentally limited by the ratio of the telescope aperture to the wavelength of the received radiation. For single element radio telescopes to approach the resolution of their optical telescope counterparts, they would need to be impractically large. Mathematical analysis of correlating two element radio telescope interferometers shows that very large aperture radio telescopes can be synthesized from a number of two element interferometers. An array of two element correlating radio telescope interferometers can be used to produce a synthesized aperture equal to the largest distance between two receiving antennas in the array. Telescope arrays thus enable very high resolution since the angular resolution of a telescope is proportional to the wavelength of the received signal divided by the aperture diameter. A spread of separation distances between antenna pairs is required to produce a complete image of the radiating sources in the field of view. Modern digital signal processing techniques can be used to provide cost effective performance and flexibility in two element correlating radio telescope interferometer design. The aim of this research project was to design and construct a two element correlating radio telescope interferometer using modern digital signal processing techniques and hardware. The relevant theory has been investigated together with suitable hardware and software platforms and tools used to produce such a system. The two element correlating radio telescope interferometer produced, will be used as a platform for further investigative research into its design, performance and application. The outcome of this research project was the successful completion of a working two element correlating radio telescope interferometer. The development process has been analysed and carefully documented. Some fringe measurements for a simple single frequency radiating point source have been taken and these measurements have been analysed according to theoretical expectation. Potential for further research, using the two element correlating radio telescope interferometer produced, has been identified and discussed.

Asian elephants utilize two chemical signals that have been described to function in reproduction: (1) (Z)-7-dodecenyl acetate (Z7-12:Ac) is released by females near ovulation, and (2) frontalin is released by males around the time of musth. Signaling theory posits that the concentration at which either compound is emitted should have implications for the response of the receiver, varying with factors such as sex and reproductive experience. Here, the objectives were to: (1) investigate the effect of concentration on receiver chemosensory behavior in an effort to identify detection thresholds and concentrations of maximum response for reproductively experienced or inexperienced male and female Asian elephants, and (2) characterize the broader behavioral impacts of each of these compounds in an effort for application as environmental enrichment in captive settings. Concentrations from 0.0 mM to 2.0 mM of both frontalin and Z7-12:Ac were bioassayed simultaneously with captive elephants housed at facilities across North America in two experiments: one that tested mid-range concentrations and a second that tested low and high concentrations. There was a general increase in chemosensory response with increasing concentration of both compounds regardless of sex or reproductive experience. Females exhibited a lower detection threshold for frontalin, and the opposite was true for males with Z7-12:Ac. Reproductive experience also influenced thresholds: inexperienced males had a higher threshold than experienced males for frontalin (the same was true for females), and experienced males were able to detect Z7-12:Ac samples as low as 10–7 mM. Aside from inexperienced males, all elephants responded maximally to the 1.0 mM samples of both compounds. Elephants exposed to mid-range concentrations of either compound showed no notable changes in behavior after application of the signals, although inexperienced males spent less time inactive and more time walking after frontalin bioassays, and inexperienced females foraged more after exposure to Z7-12:Ac. Interpreted together, this suggests that the concentration at which either compound is emitted has strong implications for chemosensory response based on the identity of the receiver in Asian elephants, although it is unclear whether these compounds have other behavioral effects that can be targeted for a goal-oriented olfactory enrichment program.

This research is concerned with algorithmic representation of technoeconomic growth concerning modern and next-generation telecommunications including the Internet service. The goal of this study thereof is to emphasize efforts to establish the associated forecasting and, the envisioned tasks thereof include : (i) Reviewing the technoeconomic considerations prevailing in telecommunication (telco) service industry and their implicating features; (ii) studying relevant aspects of underlying complex system evolution (akin to biological systems), (iii) pursuant co-evolution modeling of competitive business structures using dichotomous (flip-flop) states as seen in predator evolutions ; (iv) conceiving a novel algorithm based on information-theoretic principles toward technoeconomic forecasting on the basis of modified Fisher-Kaysen model consistent with proportional fairness concept of comsumers' willingness-to-pay, and (v) evaluating forecast needs on inter-office facility based congestion sensitive traffics encountered. Commensurate with the topics indicated above, necessary algorithms, analytical derivations and compatible models are proposed. Relevant computational exercises are performed with MatLab[TM] using data gathered from open-literature on the service profiles of telecommunication companies (telco); and ad hoc model verifications are performed on the results. Lastly, discussions and inferences are made with open-questions identified for further research. / by Raef Rashad Yassin. / Thesis (Ph.D.)--Florida Atlantic University, 2012. / Includes bibliography. / Mode of access: World Wide Web. / System requirements: Adobe Reader.

This thesis presents a comparative analysis of various low-frequency sonar signature representations and their ability to discriminate between proud targets of varying physical parameters. The signature representations used include: synthetic aperture sonar (SAS) beamformed images, acoustic color plot images, and bispectral images. A relative Mean-Square Error (rMSE) performance metric and an effective Signal-to-Noise Ratio (SNReff) performance metric have been developed and implemented to quantify the target differentiation. The analysis is performed on a subset of the synthetic sonar stave data provided by the Naval Surface Warfare Center - Panama City Division (NSWC-PCD). The subset is limited to aluminum and stainless steel, thin-shell, spherical targets in contact with the seafloor (proud). It is determined that the SAS signature representation provides the best, least ambiguous, target differentiation with a minimum mismatch difference of 14.5802 dB. The acoustic color plot and bispectrum representations resulted in a minimum difference of 9.1139 dB and 1.8829 dB, respectively / by Brenton Mallen. / Thesis (M.S.C.S.)--Florida Atlantic University, 2012. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2012. Mode of access: World Wide Web.

Abstract not available

Naveed Akhtar Malik. / Originally published as thesis (Dept. of Electrical Engineering and Computer Science, Sc.D., 1981). / Bibliography: p. 115-117.