Assessing the Cooling Effects of Different Vegetation Settings in a Hong Kong Golf Course

published_or_final_versio

Estimation of fast fading channel in impulse noise environment

This paper studies the estimation of fast fading channel in the present of impulse noise. Fast fading channel in wireless communications system is typically modeled as autoregressive (AR) process. Least-square algorithm and Kalman filter are previously proposed for estimating the AR parameters and the channel impulse response respectively using training sequence. The performance of these algorithms, however, is very sensitive to impulse noise. In this paper, a robust Kalman filter and a robust recursive least M-estimate algorithm are employed to jointly estimate the channel impulse response and the AR parameters of fast fading channel under impulse noise. Simulation showed that the proposed algorithms are much less sensitive to impulse noise than the conventional algorithms.published_or_final_versio

A multistage filterbank-based channelizer and its multiplier-less realization

This paper proposes a multistage filterbank-based channelizer for software radio base stations. The proposed channelizer is capable of receiving channels with potentially different bandwidths as required in a multi-standard cellular based station. It consists of multiple stages of DFT filter banks and efficient sample rate changers. The front-end DFT filter bank of the channelizer has a fixed number of channels but the passband supports overlap with each other. The received signals selected by a given output of this filter bank are fed into sample rate changers so that they can fit into the fixed channel spacing of the DFT filter banks in the following stages. Due to the lowered sample rate, these back-end DFT filter banks can have either fixed or variable number of channels. Repeatedly using this multistage architecture, channels with different bandwidths can be isolated. The design and implementation of the proposed channelizer are discussed in detail.published_or_final_versio

Influence of nitrogen on tunneling barrier heights and effective masses of electrons and holes at lightly-nitrided SiO2/Si interface

We have determined both the effective masses and the barrier heights for electrons and holes in pure SiO2 and lightly nitrided oxides with various nitrogen concentrations up to 4.5 at %. In contrast to previous studies which were usually carried out by assuming a value for either the effective mass or the barrier height, this study does not make such an assumption. The approach is proven to be reliable by examining the result for the well-studied pure SiO2 thin films. It is observed that with the increase of the nitrogen concentration the effective masses increase while both the barrier heights and the energy gap decrease. © 2004 American Institute of Physics.published_or_final_versio

Nitrite/nitrate levels in patients after stem cell transplant

published_or_final_versio

Very short answer questions: a novel approach to summative assessments in pathology

Background A solid understanding of the science underpinning treatment is essential for all doctors. Pathology teaching and assessment are fundamental components of the undergraduate medicine curriculum. Assessment drives learning and the choice of assessments influences students’ learning behaviours. The use of multiple-choice questions is common but is associated with significant cueing and may promote ‘rote learning’. Essay-type questions and Objective Structured Clinical Examinations (OSCEs) are resource-intensive in terms of delivery and marking, and do not allow adequate sampling of the curriculum. To address these limitations, we used a novel online tool to administer Very Short Answer questions (VSAQs) and evaluated the utility of the VSAQs in an undergraduate summative pathology assessment. Methods A group of 285 medical students took the summative assessment, comprising 50 VSAQs, 50 single best answer questions (SBAQs), and 75 extended matching questions (EMQs). The VSAQs were machine-marked against pre-approved responses, and subsequently reviewed by a panel of pathologists, with the software remembering all new marking judgements. Results The total time taken to mark all 50 VSAQs for all 285 students was 5 hours, compared to 70 hours required to manually mark an equivalent number of questions in a paper-based pathology exam. The median percentage score for the VSA test (72%) was significantly lower than that of the SBAQs (80%) and EMQs (84%), p <0.0001. VSAQs had a higher Cronbach alpha (0.86) than SBAQs (0.76), and EMQs (0.77). VSAQs, SBAQs and EMQs had a mean point-biserial of 0.35, 0.30 and 0.28, respectively. Conclusions VSAQs are an acceptable, reliable and discriminatory method for assessing pathology, and may enhance students’ understanding of how pathology supports clinical decision-making and clinical care by changing learning behaviour

Randomised trial of candesartan and enalapril (RACE) in the treatment of hypertension - final results

published_or_final_versio

The depth-profiled carrier concentration and scattering mechanism in undoped GaN film grown on sapphire

The carrier concentration and scattering mechanism in undoped GaN film grown on sapphire were investigated. The film was grown on sapphire using metal organic chemical vapor deposition (MOCVD). Confocal micro-Raman spectroscopic measurements and temperature-dependant Hall (TDH) measurements were performed for the study of the depth distribution of the carrier density across the GaN film. The existence of a nonuniform spatial distribution of free carriers in the film with a highly conductive layer of ∼1 μm thickness near the GaN sapphire boundary was confirmed from the study. The electron mobility limiting effect of nitrogen vacancies on GaN bulk film was also discussed.published_or_final_versio