Data association problem for multitarget tracking is determination of the relationship between targets and the incoming measurements from sensors of the target tracking system. Performance of a multitarget tracking system is strongly related to the chosen method for data association and target tracking algorithm. Incorrect data association effects state estimation of targets. In this thesis, we propose a new multi-scan data association algorithm for multitarget tracking systems. This algorithm was implemented by using MATLAB programming tool. Performances of the new algorithm and JPDA method for multiple targets tracking are compared. During simulations linear models are used and the uncertainties in the sensor and motion models are modeled by Gaussian density. Simulation results are presented. Results show that the new algorithm&#039 / s performance is better than that of JPDA method. Moreover, a survey over target tracking literature is presented including basics of multitarget tracking systems and existing data association methods.

In this thesis, we considered the problem of frame synchronization and channel estimation in Orthogonal Frequency Division Multiplexing (OFDM) systems. Since framing error may cause severe ISI and may disturb the orthogonality of the subcarriers, frame synchronization must be accomplished at the OFDM receiver. Furthermore, the effects of channel must be compensated to obtain the symbols accurately. We investigated several frame synchronization algorithms including a maximum likelihood (ML) synchronizer which relies on the periodicity induced in the OFDM structure, and a robust synchronizer which uses a special training symbol. These algorithms are evaluated in AWGN and Rayleigh fading multipath channels and performances are compared in terms of percentage of ISI-free synchronization, mean squared error and symbol error rate. The IEEE 802.11a framework is used to compare these algorithms with the standard system which utilizes training symbols dedicated for synchronization. It is shown that an adjustment for the frame start estimates must be done to avoid the effects of the channel delay spread. It is also pointed that ideal synchronization is not necessary unless symbol boundaries are detected inside an ISI-free region and the error aroused in ISI-free synchronization can be compensated by applying channel estimation and equalization regarding the same symbol boundaries.

Sampling and reconstruction is used as a fundamental signal processing operation since the history of signal theory. Classically uniform sampling is treated so that the resulting mathematics is simple. However there are various instances that nonuniform sampling and reconstruction of signals from their nonuniform samples are required. There exist two broad classes of reconstruction methods. They are the reconstruction according to a deterministic, and according to a stochastic model. In this thesis, the most fundamental aspects of nonuniform sampling and reconstruction, according to a deterministic model, is analyzed, implemented and tested by considering specific nonuniform reconstruction algorithms. Accuracy of reconstruction, computational efficiency and noise stability are the three criteria that nonuniform reconstruction algorithms are tested for. Specifically, four classical closed form interpolation algorithms proposed by Yen are discussed and implemented. These algorithms are tested, according to the proposed criteria, in a variety of conditions in order to identify their performances for reconstruction quality and robustness to noise and signal conditions. Furthermore, a filter bank approach is discussed for the interpolation from nonuniform samples in a computationally efficient manner. This approach is implemented and the efficiency as well as resulting filter characteristics is observed. In addition to Yen&#039 / s classical algorithms, a trade off algorithm, which claims to find an optimal balance between reconstruction accuracy and noise stability is analyzed and simulated for comparison between all discussed interpolators. At the end of the stability tests, Yen&#039 / s third algorithm, known as the classical recurrent nonuniform sampling, is found to be superior over the remaining interpolators, from both an accuracy and stability point of view.

In this thesis, reduction of the Peak-to-Average Power Ratio (PAPR) of Orthogonal Frequency Division Multiplexing (OFDM) is studied. A new PAPR reduction method is proposed that is based on block coding the input data and modifying the codeword until the PAPR is reduced below a certain threshold. The method makes use of the error correction capability of the block code employed. The performance of the algorithm has been investigated through theoretical models and computer simulations. For performance evaluation, a new gain parameter is defined. The gain parameter considers the SNR loss caused by modification of the codeword together with the PAPR reduction achieved. The gain parameter is used to compare a plain OFDM system with the system employing the PAPR reduction algorithm. The algorithm performance is examined through computer simulations and it is found that power reductions around 2-3 dB are obtained especially for low to moderate number of channels and relatively strong codes.

Characterization of nonlinear systems is a challenging task as the output can not be expressed simply in terms of input signal. Therefore, a universal analysis method is essential to simplify this procedure. Modeling of the input signal is a crucial part of such analysis. In this thesis, multi-tone representation is employed to model arbitrary, stochastically not well-defined input signals and thereafter characterize nonlinear systems. In order to verify the validity of multitone representation, multi-tone modeling concept is primarily applied to real life amplifier characterization in single amplifier configuration. This experiment demonstrated potential of multi-tone modeling concept in nonlinear system characterization and encouraged application of the concept to analysis of feedforward linearizers, which are complicated systems due to the presence of two nonlinear amplifiers and the requirement of strict amplitude, phase and delay matching within two loops of the circuit. It has been assumed that main and error amplifiers can be modeled with third order AM/AM nonlinearities and there exists no delay mismatch within the loops. Hence, closed form expressions relating the main and adjacent channel power at the output of the feedforward system to the system parameters are obtained. The developed model is verified by RF and system simulations. As a result, a mathematical handy tool to specify circuit parameters rapidly for optimum linearity performance and efficiency is achieved.

In this work interception and spreading sequence estimation of Direct Sequence Spread Spectrum (DSSS) signals, in low signal to noise power ratios is discussed. For interception an approach based on autocorrelation fluctuations is employed and also symbol period is estimated from this interception process. Spreading sequence estimation is performed by using eigenanalysis of the correlation matrix and estimated symbol period. These approaches are applied on different kinds of DSSS signals including 3rd generation UMTS signal and LPI radar signals. In order to examine the channel effects such as / multipath, interference and colored noise, on the performance of applied techniques, detailed analysis results are obtained. The results are compared with the performances of alternative interception techniques.

Frequency modulated continuous wave (FM-CW) radar altimeters are used in civil and military applications. Proximity fuses, automatic cruise control systems of cars, radar altimeter of planes are examples to these applications. The goal of this thesis is to present a method for altitude determination using an FM-CW radar. For this purpose principles of radars and FM-CW systems are studied and related subjects are inspected. After this inspection, algorithms for altitude determination are evaluated. Consequently signal detection and processing methods are proposed to build an altitude determining algorithm. Also an analytical test environment for altitudes between 100 m and 4000 m is developed in computer as a result of researches. Test environment simulated the performance of altitude determining algorithm and FM-CW Radar Altimeter. The hardware is designed and implemented accordingly.

In this thesis, the target tracking problem with input estimation is investigated. The estimation performance of the optimum decoding based smoothing algorithm and a target tracking scheme based on the Kalman filter is compared by performing simulations. The advantages and the disadvantages of these algorithms are presented.

Background Many trials in the USA, Canada, Europe and Australia have attempted to evaluate the effectiveness of preventive in-home health assessment and home care programs for older people. Trials have differed widely in their processes, including the dependence levels of subjects, assessment components and locations (clinic/home), intensity of case management (frequency of contact, length of follow-up period, scope of interventions) and methods of case management (telephone/visits). Preventive programs use valuable health resources and, although there has been inconclusive evidence of their effectiveness, programs combining preventive in-home health assessment and home care for older people have been introduced into public policy in Australia and internationally. Ongoing research is therefore essential in order to identify the positive benefits for older people, and establish their effectiveness with regard to health resource utilisation. Purpose The purpose of the study was to maintain the health status of older people living alone in the community by implementing a preventive health assessment and follow-up home care program. Research Design An experimental group was compared with a control group using a cluster randomised controlled trial methodology. Health outcomes were measured pre and post intervention, including health perception, functional ability, psychosocial status, client satisfaction, and health resource utilisation. Population and Sample The population for this study consisted of people aged 75 years and over who lived alone in Independent Living Units within managed retirement facilities, and who were highly independent in their activities of daily living. The final sample totalled 124, comprising of an experimental group (n=61) and a control group (n=63). The sample resided in South East Queensland. Intervention The intervention for the study "A Community Preventive Health Model for over 75s Living Alone" comprised of five major elements: 1) targeting before health and/or social crisis, and while community care needs were low; 2) linking clients with a community nurse; 3) comprehensive health assessments and identification of needs; 4) introduction of basic health care and community services and referrals if required; and 5) case management by three-monthly telephone contact. Assessments and case management were carried out by experienced community care registered nurses, and case management was performed for a one year period. The control group received health assessments and phone calls similar to the experimental group for data collection purposes, and to balance the risk of a Hawthorne effect due to regular contacts with participants. However all aspects of case management were omitted from all episodes of contact with the control group. For ethical reasons control group participants were supplied with a summary of their health assessment results to share with their GP if they wished. Data Collection and Instruments Measures of health perception, functional ability and psychosocial status occurred at two points (baseline and after 12 months). Measures of health resource utilisation, mortality and client satisfaction were measured after twelve months. A combination of several widely-used, valid and reliable instruments, as well as some newly developed data collection tools, were used to measure health outcomes. Data Analysis Independent group t-tests and Chi-square tests were used to examine for baseline differences between the experimental and control groups, and also to analyse health resource utilisation data at Time 2. A series of ANCOVA tests were applied to test the remaining hypotheses, so that the effects of Time 1 scores and potential confounding variables could be incorporated into the analyses. Results The experimental group and control group were homogenous at baseline for all demographic variables and all major outcome variables. The intervention model was applied for one year, with 66% (n = 40) in the experimental group having at least one unmet need identified and appropriate interventions undertaken. Only a small proportion of interventions (16%) were recorded as not being followed through by clients, and the majority (59%) resulted in needs being met or problems resolved. Results showed no benefits were gained from the program after one year for experimental group participants for the outcomes of health perception, functional ability, psychosocial status, health resource utilisation and mortality. However, the experimental group did show a statistically significantly higher level of satisfaction with care. Conclusions Comprehensive assessments performed by Registered Nurses with expertise in gerontology resulted in the identification of previously undetected unmet needs. When comprehensive assessment was combined with low intensity case management for a one year period, higher levels of client satisfaction with care were achieved. Therefore a model involving Registered Nurses with advanced knowledge and experience in aged care, working in collaboration with General Practitioners and community service organisations, could have considerable benefits in identifying unmet needs and improving client satisfaction. However, no client benefit was detected for quality of life outcomes, nor was a reduction in health resource utilisation found. This result from an Australian cohort is consistent with findings from many other international trials (Van Haastregt et al., 2000). It is possible that methodological issues are masking the effect of the intervention. Are we measuring appropriate outcomes? Are we expecting long-term outcomes in short time frames? Are we applying the model appropriately across a diverse older population? Further research to explore these questions is recommended for the future.

Background: Older adults experience health deconditioning during hospitalization. There are many facets of care impacting on older adults' health characteristics and their self confidence in managing their health. The aim of this follow-up study is to examine the long term effect of comprehensive discharge planning and nursing in-home follow-up for older adults (over 65 year old) incorporating physiotherapy exercise strategies on health characteristics. No published studies were located that had examined the impact of a comprehensive discharge program on the functional status and psychosocial among older frail adults at 12 months post-discharge. Design and methodology: Rehabilitation in Older People (RIO program) is a randomised controlled trial which evaluates the intervention of a comprehensive discharge program, exercise program incorporating nursing follow up. Participants of the RIO study were randomly allocated into usual care control group and an intervention group. The intervention group received a comprehensive training from an advanced practice gerontic nurse (APGN) and exercise strategies by physiotherapists. The APGN visited the participants in their home 48 hours post discharge, followed by telephone follow-up at 4, 8, 12 and 24 weeks. This study followed-up this cohort at 12 month via telephone interviews to evaluate their functional ability, quality of life, psychosocial characteristics and the levels of self-efficacy. The General Self-efficacy Scale (GSE) was used to measure their self-efficacy. Results: There is no difference between the demographic and health characteristics between the control and intervention group. There are significant difference in their functional ability, psychosocial health, measured by the tools mentioned above at 4 weeks (p < 0.05), 12 weeks (p < 0.05), and 24 weeks (p < 0.05), but not at 52 weeks. The possible reason could be due to lack of telephone follow up. Moreover, the levels of self-efficacy in this sample have been found to correlate with the functional ability and psychosocial at 12 months after discharge from an acute hospital.