4,777 research outputs found
Discovery of the human genome sequence in the public and private databases
No full textAbstractGenomes: Much heat has been generated in discussions about the key human genome sequence databases, generated by the Human Genome Project and Celera, and what specific features each offers genome researchers. Stephen W. Scherer and Joseph Cheung, who are intense users of both, offer a personal assessment of the developing contents
Adaptive equalisers for wideband time division multiple access mobile radio
No full textThe detection of partial response continuous phase modulated (CPM) signals transmission over wideband time division multiple access (TDMA) mobile radio channels is addressed. The design of adaptive equalisers to accommodate channels having long excess delays while maintaining an acceptable performance is the central core of the investigation. Maximum likelihood sequence estimation (MLSE) detector in the form of the Viterbi equaliser is described and its performance in narrowband and wideband radio channels is studied. Binary digital phase modulation (DPM) employing a three-bit raised-cosine (3-RC) phase shaping filter and a modulation index of 1.08 was used to convey data over a flat Rayleigh fading channel. A signal-to-noise ratio of 27dB was required to achieve a bit error rate (BER) of 10-3. For transmission to DPM data over Rician fading channels, the BER improved with the K-factor values. The DPM transmissions over wideband channels yielded performance gains provided the entire length of the channel impulse response was utilised by the Viterbi equaliser. A 9dB gain in SNR was obtained with two-path Rayleigh fading channels compared to flat Rayleigh fading channel. In channels exhibiting exceedingly large excess path delays, as found in mountainous regions, the complexity required by the conventional Viterbi equaliser is prohibitively high. To accommodate these massive path delays we propose a modified Viterbi equaliser which explicitly exploits the inherent diversity effect innate in wideband radio channels. A separate metric calculator is used for each resolvable component in the channel impulse response and these metric calculator outputs are combined to give the overall metric for a simple Viterbi processor. The equaliser performance was found to be nearly identical to that of the original Viterbi equaliser for SNR< 15dB. The complexity was only about 25% of that required by the original Viterbi equaliser capable of handling channels having the same excess delay. Decision feedback equalisation (DFE) for CPM signals is also considered. The error propagation caused by incorrect decision in the feedback filter is addressed. A hybrid combination of the DFE and the Viterbi processor is proposed which allows soft-decisions to be made and incorrect decisions to be changed to curtail error propagation in the DFE. This arrangement we designated as the Soft-Decision Feedback Equaliser (SDFE). The performance of the SDFE approaches that of the original Viterbi equaliser with discrepancies in channel SNR of 1.5dB and 2dB at BERs of 10-2 and 10-3, respectively when transmission as over a two-path Rayleigh fading channel. For the GSM hilly terrain (HT) and the equaliser test (EQ) channel models, up to 75% of the sequence feedback changes made to the DFE were successful for moderate SNR, say 15dB. The SDFE has the attractive characteristic of being able to trade complexity and performance by operating between a full Viterbi equaliser and a simple DFE. For typical implementation of the SDFE, the complexity ranged from 25% to 50% of the original Viterbi equaliser.</p
Some Weighted Hardy-type Inequalities of Vector-Valued Functions
No full textBy adopting the C-technique of Cheung and Pečrić, we establish some interesting weighted Hardy-type inequalities of vector-valued functions. These generalize and improve some existing results of Cheung, Cheung-Hanjš-Pēcarić, Hanjš-Love-Pečarić, Levinson, and Pachpatte. [ABSTRACT FROM AUTHOR
Supplemental material for The subjective well-being of academically gifted students in the Chinese cultural context
No full textSupplemental material for The subjective well-being of academically gifted students in the Chinese cultural context by Xinjie Chen, Xitao Fan, Hoi Yan Cheung and Joseph Wu in School Psychology International</p
Computer modelling of transient heat flow in mines
No full textPhD ThesisThe traditional method to predict air temperatures in mine roadways is based on
the assumption that the ventilation air temperature remains constant over the
ventilated age of the roadway. Hence, a steady-state solution prevails. As the capital
investment of providing an acceptable working environment in hot and deep mines is
increasing, more accurate and reliable temperature predictions in mine roadways will
be needed in future mine ventilation planning. For this reason, a transient model to
predict weekly air temperatures in mine roadways is developed.
The transient model is presented in the form of a computer program. It is
constructed from the mathematical techniques developed for calculating the transient
heat flow from strata (Cheung, 1988), conveyed coal (Cheung and Rabia, 1989) and
structural steel (Maneylaws, 1988), and the empirical equations developed by
Browning et al (1981) for estimating the heat from machinery. Duhamel's Theorem
is used in the mathematical technique for calculating the transient heat flow from
strata and conveyed coal. Details of these techniques are derived. In addition, the
algorithm of the computer program is presented in terms of flow charts.
Climatic investigations were undertaken at British Coal Collieries; three sites at
Wearmouth Colliery, Sunderland, and one site at Whitemoor Colliery, Selby. During
the investigations, temperature surveys were conducted at all the sites. Using the data
collected from these sites, the transient model is validated against field measurements
and agreeable correlation achieved. Moreover, recommendations are made to improve
the model
汉英同传中删减与增译现象的案例分析
No full textAuthor name used in this publication: 张其帆, Cheung Kay-fan AndrewTitle in Traditional Chinese: 漢英同傳中刪減與增譯現象的案例分析Journal title in Traditional Chinese: 中國翻譯2011-2012 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishedVoR allowe
Xin li ji jiu yu wei ji shi jian he zai nan zhong zuo wei gong gong wei sheng zai nan ying dui zhun bei de ce lüe
No full textCheung, Yee Lai.Thesis Ph.D. Chinese University of Hong Kong 2014.Includes bibliographical references (leaves 193-207).Abstracts and some appendixes also in Chinese.Title from PDF title page (viewed on 02, December, 2016).Cheung, Yee Lai
Characterization of Human Papillomavirus Type 58 E7 Protein Variant T20I/G63S
No full textCheung, Pui Yiu Grace.Thesis M.Phil. Chinese University of Hong Kong 2016.Includes bibliographical references (leaves ).Abstracts also in Chinese.Title from PDF title page (viewed on …)
Minority Media Production Practices and Cultural Citizenship in Hong Kong
No full textChong, Cheung Kwan Cindy.Thesis Ph.D. Chinese University of Hong Kong 2016.Includes bibliographical references (leaves ).Abstracts also in Chinese.Title from PDF title page (viewed on …)
Directed Multigraph of Networks
No full textCheung, King Chau.Thesis Ph.D. Chinese University of Hong Kong 2016.Includes bibliographical references (leaves ).Abstracts also in Chinese.Title from PDF title page (viewed on …)
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