Three investigations were conducted on the nature of the radiance field in clear ocean water. It is important to understand the sunlight intensity below the sea surface because this leads to an understanding of how ocean creatures navigate in shallow and deep water. The nature of the radiance field is also gives an understanding of the living environment for ocean animals. Hydrolight 4.1, a simulation software developed by Curtis D. Mobley, was used to calculate the spectral radiance in clear ocean water for multiple wavelengths from the surface down through the asymptotic region. The first study found, as expected, that Raman scattering has little effect on wavelengths of light that are less than 500 nm. The effect of Raman scattering increases with increasing wavelength, and with increasing depth. The second study found the region of the water column where the radiance field is asymptotic. The third investigation found the effect of changing the mean square slope, or variance of the water-wave slope distribution. This effect is greatest near the surface and for a more truncated mean square slope integral. There are three peaks in percent difference to the ideal case, near the surface, one in the solar beam and the others near the critical angle of water.

In this thesis, we investigate the CDMA (Code Division Multiple Access) multi- user detection scheme where the DD (Decorrelating Detector) is used to eliminate the multiple access interference. The DD algorithm need to compute the inverse of the matrix involves a great deal of computation, especially when the number of users is large. A recursive method with the LMS (Least-Mean-Square) algorithm, namely the decorrelating transversal filter, to detect users¡¦ signals adaptively can reduce greatly the computational complexity of a CDMA multi-user detector. In this thesis, we focus on the hardware FPGA (Fdield Programmable Gate Array) implementation of the decorrelating transversal filter. The functional system simulation of the decorrelating transversal filter is carried out by using Matlab first. Then this filter is implemented by the Xilinx FPGA and its system performance is also verified.

Microscopic traffic simulation is useful tool in analysing traffic and estimating the capacity and level of service of road networks. In this thesis, the four legged Idrottsparken roundabout in the city of Norrkoping in Sweden is analysed by using the microscopic traffic simulation package AIMSUN. For this purpose, data regarding traffic flow counts, travel times and queue lengths were collected for three consecutive weekdays during both the morning and afternoon peak periods. The data were then used in model building for simulation of traffic of the roundabout. The Root Mean Square Error (RMSE) method is used to get the optimal parameter value between queue length and travel time data and validation of travel time data are carried out to obtain the basic model which represents the existing condition of the system. Afterward, the results of the new models were evaluated and compared to the results of a SUMO model for the same scenario model. Based on calibrated and validated model, three alternative scenarios were simulated and analysed to improve efficiency of traffic network in the roundabout. The three scenarios includes: (1) add one free right turn in the north and east sections; (2) add one free right turn in the east and south sections; and (3) addition of one lane in roundabout. The analysis of these scenarios shows that the first and second scenario are only able to reduce the queue length and travel time in two or three legs, while the third scenario is not able to improve the performance of the roundabout. In this research, it can be concluded that the first scenario is considered as the best scenario compared to the second scenario and the third scenario. The comparison between AIMSUN and SUMO for the same scenario shows that the results have no significance differences. In calibration process, to get the optimal parameter values between the model measurements and the field measurements, both of AIMSUN and SUMO uses two significantly influencing parametersfor queue and travel time. AIMSUN package uses parameter of driver reaction time and the maximum acceleration, while SUMO package uses parameter of driver imperfection and also the driver rection time.

In this thesis, we investigate the problem of channel estimation in the amplify-and-forward cooperative communication systems when the networks could be in the presence of selfish relays. The information received at the destination will be detected and then used to estimate the channel. In previous studies, the relays will deliver the information under the prerequisite for cooperation and the destination can receive the information sent from the source without any possible selfish relay. Therefore, the channel will be estimated under this over idealistic assumption. Unfortunately, the assumption does not make sense in real applications. Currently, we don¡¦t have a mechanism to guarantee the relays will always be cooperative. The performance of channel estimation will be significantly degraded when the selfish relays present in the network. Therefore, this thesis considers an amplify-and-forward cooperative communication system with direct transmission and proposes a detection mechanism to overcome the misbehaving relay problem. The detection mechanism employed estimation is based on likelihood ratio test using both direct transmission and relayed information. The detection result will then be used to reconstruct the codeword used for estimating product channel gain of the source-to-relay and relay- to-destination links. The mathematical derivation for the considered problem is developed and numerical simulations for illustration is also carried out in the thesis. The numerical simulation results verify that the proposed method is indeed able to achieve robust channel estimation.

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Empowered by linear precoding and decoding, a spatially multiplexed multiple-input multiple-output (MIMO) system becomes a convenient framework to offer high data rate, diversity and interference management. While most of the current precoding/decoding designs have assumed perfect channel state information (CSI) at the receiver, and sometimes even at the transmitter, in this thesis we design the precoder and decoder with imperfect CSI at both the transmit and the receive sides, and investigate the joint impact of channel estimation errors and channel correlation on system structure and performance. The mean-square error (MSE) related performance metrics are used as the design criteria. We begin with the minimum total MSE precoding/decoding design for a single-user MIMO system assuming imperfect CSI at both ends. Here the CSI includes the channel estimate and channel correlation information. The structures of the optimum precoder and decoder are determined. Compared to the perfect CSI case, linear filters are added to the transceiver structure to improve system robustness against imperfect CSI. The effects of channel estimation error and channel correlation are quantified by simulations. With imperfect CSI at both ends, the exact capacity expression for a single-user MIMO channel is difficult to obtain. Instead, a tight capacity lower-bound is used for system design. The optimum structure of the transmit covariance matrix for the lower-bound has not been found in the existing literature. By transforming the transmitter design into a joint precoding/decoding design problem, we derive the expression of the optimum transmit covariance matrix. The close relationship between the maximum mutual information design and the minimum total MSE design is also discovered assuming imperfect CSI. For robust multiuser MIMO communications, minimum average sum MSE transceiver (precoder-decoder pairs) design problems are formulated for both the uplink and the downlink, assuming imperfect channel estimation and channel correlation at the base station (BS). We propose improved iterative algorithms based on the associated Karush-Kuhn-Tucker (KKT) conditions. Under the assumption of imperfect CSI, an uplink--downlink duality in average sum MSE is proved. As an alternative for the uplink optimization, a sequential semidefinite programming (SDP) method is proposed. Simulation results are provided to corroborate the analysis. / Thesis (Ph.D, Electrical & Computer Engineering) -- Queen's University, 2008-07-25 10:53:45.175

This paper investigates the effect of parameter selection for the decision feedback equalization (DFE) on communication performance through a dispersive underwater acoustic wireless channel (UAWC). A DFE based on minimum mean-square error (MMSE-DFE) criterion has been employed in the implementation for evaluation purposes. The output from the MMSE-DFE is input to the decoder to estimate the transmitted bit sequence. The main goal of this experimental simulation is to determine the best selection, such that the reduction in the computational overload is achieved without altering the performance of the system, where the computational complexity can be reduced by selecting an equalizer with a proper length. The system performance is tested for BPSK, QPSK, 8PSK and 16QAM modulation and a simulation for the system is carried out for Proakis channel A and real underwater wireless acoustic channel estimated during SPACE08 measurements to verify the selection.

An optical study of Mn and Mo isotopes has been performed in two contrasting regions of the nuclear chart. Collinear laser spectroscopic methods were employed using the Ion Guide Separator On-Line (IGISOL) at the University of Jyväskylä, Finland. Optical pumping in an ion-trap with the use of frequency quadrupled titanium sapphire lasers, greatly improved the efficiency of the spectroscopy performed.For the first time, the change in mean-square charge radius was determined for ground and isomeric states in 50-56Mn with a sharp shell closure seen across N = 28. Nuclear quadrupole moments in 50m,53,54,56Mn were also extracted, displaying trends similar to those of the charge radii. Newly extracted hyperfine structures and isotope shifts of 90-92,94-98,100,102-106,108Mo span the N = 50 shell closure and well-known N = 60 shape change. Unlike the Z = 38 - 41 isotopic chains, Mo exhibits a smooth increase in mean-square charge radius, with no sudden onset of deformation at N = 60. These measurements signify the end point of this strongly deformed A ~ 100 region in both Z and N. In the Z ~ 40 region, the charge radii follow the trends in the mass measurements near perfectly. However, in the Mn measurements a clear disparity between the mass and charge radii measurements is seen across the N = 28 magic shell closure. The absence of any shell effects in the Mn mass measurements show the importance of charge radii measurements, with pertinent implications for future investigations in the N = 40 region. Additionally, a portable data acquisition system for laser spectroscopy has been successfully tested. It is based on the LabJack system which will directly interface to a USB connection. It is able to register individual photons from amplified and converted photomultiplier tube signals (with bunched or continuous ion beams). The device drives a Cooknell voltage supply, which steps the voltage across the laser-ion interaction region. The introduction of an accurate 100 ms time window into the LabJack system has enabled a precise photon detection system for future off-line testing and on-line use. Further to this, a new method of locating hyperfine resonances has been introduced into our spectroscopy.

In this dissertation, new theoretical results are obtained for bounding convergence and mean-square error in conditional coding. Further new statistical methods for the practical application of conditional coding are developed. Criteria for the uniform convergence are first examined. Conditional coding Markov chains are aperiodic, π-irreducible, and Harris recurrent. By applying the general theories of uniform ergodicity of Markov chains on genera l state space, one can conclude that conditional coding Markov cha ins are uniformly ergodic and further, theoretical convergence rates based on Doeblin's condition can be found. Conditional coding Markov chains can be also viewed as having finite state space. This allows use of techniques to get bounds on the second largest eigenvalue which lead to bounds on convergence rate and the mean-square error of sample averages. The results are applied in two examples showing that these bounds are useful in practice. Next some algorithms for perfect sampling in conditional coding are studied. An application of exact sampling to the independence sampler is shown to be equivalent to standard rejection sampling. In case of single-site updating, traditional perfect sampling is not directly applicable when the state space has large cardinality and is not stochastically ordered, so a new procedure is developed that gives perfect samples at a predetermined confidence interval. In last chapter procedures and possibilities of applying conditional coding to mixture models are explored. Conditional coding can be used for analysis of a finite mixture model. This methodology is general and easy to use.

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