MIMO Channel Estimation and Tracking Based on Polynomial Prediction With Application to Equalization

This paper presents a multiple-input-multiple-output (MIMO) receiver design with integrated channel estimation and tracking for a time-varying frequency-selective Rician or Rayleigh fading environment. It first extends a polynomial-predictor-based channel estimation and tracking approach to a MIMO system. The structure and complexity of the estimator are similar to that of an optimum estimator using a Kalman filter, but it does not require a priori knowledge of the channel statistics. It employs a fixed-state transition matrix using precomputed polynomial coefficients and can be used in a Rician fading environment without reconfiguration. It is integrated with a MIMO minimum-mean-squared-error decision feedback equalizer, and simulation results show that the system performance using the estimator can be made comparable to that employing a Kalman estimator under a broad range of channel conditions.     

Design Of Robust Pid Controllers

In this paper, a new method is proposed to design the robust PID controllers for uncertain linear time‐invariant systems. We describe a simple and programming procedure for designing PID controllers by applying Kharitonov's theorem and LMI method. Such a controller enables the resulting control system to achieve robust stability as well as asymptotic tracking.     

Pentagon-shaped 0 degrees -cut BaTiO3 as an efficient self-pumped phase conjugator

A pentagon-shaped 0(o)-cut undoped BaTiO(3) crystal was used to construct a high-quality self-pumped phase conjugator. The conjugator shows a steady phase-conjugate output with a high reflectivity (as high as ~68%), a fast rising time, and a large angular range of acceptance. It also shows a good fidelity in the phase-conjugate reconstructed image; the resolution reaches 17 mum.     

Equilibrium theory of a pressure swing adsorption process

An equilibrium theory of the separation of two-component gaseous mixtures via the pressure swing adsorption process known as heatless adsorption is presented. Both components of the mixture are adsorbable. One is present at a trace level and is preferentially adsorbed.Principal predictions of the theory for the condition of complete removal of the trace component from the high pressure product stream when using the least possible amount of adsorbent are as follows. When the separation factor is large, high recovery of purified high pressure product is obtained and blowdown and purge losses are small. Recovery is increased and losses decreased by increasing the pressure ratio. Conversely, recovery of the purif high pressure product is small and blowdown and purge losses are large when the separation factor is small. In this case the use of high pressure ratio not improve performance.The trace level component in the combined blowdown and purge stream is derived increasingly from the blowdown as the pressure ratio is increased.     

Formation of Al2Cu and AlCu intermetallics in Al(Cu) alloy matrix composites by reaction sintering

We report the fabrication and characterization of a series of Al(Cu) alloy-based matrix composites. The composites were produced by sintering and rapid quenching three powder mixtures of Al and Cu with hypoeutectic, eutectic, and hypereutectic compositions. The morphology of the reinforcements formed in the Al(Cu) matrices of these composites was found to be variable. A two-phase Al₂Cu–Al(Cu) nanoeutectic, with lamellar spacing of 200–300 nm, was found in the Al(Cu) matrix of the sample having hypoeutectic composition after it was oil-quenched from 1000 °C to room temperature. While oil quenching the sample with eutectic composition, produced single Al₂Cu crystals of 2–2.5 μm size, embedded in a lamellar nanoeutectic matrix. As for the hypereutectic alloy, the matrix of the oil-quenched sample consisted mainly of Al₂Cu intermetallic, and a secondary phase of AlCu dendrites with dendrite arms spacing of 1–1.5 μm.     

Genus zero surface conformal mapping and its application to brain surface mapping

We developed a general method for global conformal parameterizations based on the structure of the cohomology group of holomorphic one-forms for surfaces with or without boundaries (Gu and Yau, 2002), (Gu and Yau, 2003). For genus zero surfaces, our algorithm can find a unique mapping between any two genus zero manifolds by minimizing the harmonic energy of the map. In this paper, we apply the algorithm to the cortical surface matching problem. We use a mesh structure to represent the brain surface. Further constraints are added to ensure that the conformal map is unique. Empirical tests on magnetic resonance imaging (MRI) data show that the mappings preserve angular relationships, are stable in MRIs acquired at different times, and are robust to differences in data triangulation, and resolution. Compared with other brain surface conformal mapping algorithms, our algorithm is more stable and has good extensibility.     

Risk factors affecting the severity of single vehicle traffic accidents in Hong Kong

A population-based case-control study was conducted to examine factors affecting the severity of single vehicle traffic accidents in Hong Kong. In particular, single vehicle accident data of three major vehicle types, namely private vehicles, goods vehicles and motorcycles, which contributed to over 80% of all single vehicle accidents during the 2-year-period 1999-2000, were considered. Data were obtained from the newly implemented traffic accident data system (TRADS), which was developed jointly by the Transport Department, Police Force and Information Technology Services Department, Hong Kong. The effect of district, human, vehicle, safety, environmental and site factors on injury severity of an accident was examined. Unique risk factors associated with each of the vehicle types were identified by means of stepwise logistic regression models. For private vehicles, district board, gender of driver, age of vehicle, time of the accident and street light conditions are significant factors determining injury severity. For goods vehicles, seat-belt usage and weekday occurrence are the only two significant factors associated with injury severity. For motorcycles, age of vehicle, weekday and time of the accident were determined to be important factors affecting the injury severity. Identification of potential risk factors pertinent to the particular vehicle type has important implications to relevant official organisations in modifying safety measures in order to reduce the occurrence of severe traffic accidents, which would help to promote a safe road environment.     

A bivariate zero-inflated Poisson regression model to analyze occupational injuries

The aim of many occupational safety interventions is to reduce the incidence of injury. However, when measuring intervention effectiveness within a period, population-based accident count data typically contain a large proportion of zero observations (no injury). This situation is compounded where injuries are categorized in a binary manner according to an outcome of interest. The distribution thus comprises a point mass at zero mixed with a non-degenerate parametric component, such as the bivariate Poisson. In this paper, a bivariate zero-inflated Poisson (BZIP) regression model is proposed to evaluate a participatory ergonomics team intervention conducted within the cleaning services department of a public teaching hospital. The findings highlight that the BZIP distribution provided a satisfactory fit to the data, and that the intervention was associated with a significant reduction in overall injury incidence and the mean number of musculoskeletal (MLTI) injuries, while the decline in injuries of a non-musculoskeletal (NMLTI) nature was marginal. In general, the method can be applied to assess the effectiveness of intervention trials on other populations at high risk of occupational injury.