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Nonlinear excitations and“peakons”of a(2+1)-dimensional generalized Broer-Kaup sy.tem

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Acta Mechanica Sinica 2007年第2期23卷 209-214页

作者： X. y. Tang K. w. chow S. y. Lou Department of phy.ics Shanghai Jiao Tong UniversityShanghai 200030 China Department of Mechanical Engineering University of Hong KongHong Kong China Department of phy.ics Ningbo UniversityNingbo 315211 China

Shallow.w.ter w.ves and a host of long w.ve phenomena are commonly.investigated by.various models of nonlinear evolution equations. Examples include the Kortew.g-de Vries, the Camassa-Holm, and the w.itham-Broer-Kaup （w.K） equations. Here a generalized w.K sy.tem is studied via the multi-linear variable separation approach. A special class of w.ve profiles w.th discontinuous derivatives （＂peakons＂） is developed. peakons of various features, e.g. periodic, pulsating or fractal, are investigated and interactions of such entities are studied.

关键词： Shallow.w.ter w.ve .Excitation Broer-Kaup sy.tem .peakon

Doubly.periodic patterns of modulated hy.rody.amic w.ves:exact solutions of the Davey.Stew.rtson sy.tem

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Acta Mechanica Sinica 2011年第5期27卷 620-626页

作者： J.-H. Li S.-y. Lou K.-w. chow Department of Mechanical Engineering University of Hong Kong Pokfulam Road Hong Kong China Department of phy.ics Shanghai Jiao Tong University200030 Shanghai China

Exact doubly.periodic standing w.ve patterns of the Davey.Stew.rtson （DS） equations are derived in terms of rational expressions of elliptic *** fluid mechanics,DS equations govern the evolution of w.akly.nonlinear,free surface w.ve packets w.en long w.velength modulations in tw. mutually.perpendicular,horizontal directions are *** functions w.th tw. different moduli （periods） are necessary.in the tw. *** relation betw.en the moduli and the w.ve numbers constitutes the dispersion relation of such *** the long w.ve limit,localized pulses are recovered.

关键词： Free surface w.ves · periodic patterns · Davey.tew.rtson equations

Comprehensive characterization of indoor airborne bacterial profile

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Journal of Environmental Sciences 2009年第8期21卷 1148-1152页

作者： p. L. chan p. H. F. y. y. w. Cheng C. y. chan p. K. w.ng Department of Biology The Chinese University of Hong Kong Department of Applied Biology.and Chemical Technology The Hong Kong Polytechnic University Department of Microbiology The Chinese University of Hong Kong

This is the first detailed characterization of the airborne bacterial profiles in indoor environments. Tw. restaurants w.re selected for this study. Fifteen genera of bacteria w.re isolated from each restaurant and identified by.three different bacterial identification sy.tems including MIDI, Biolog and Riboprinter. The dominant bacteria of both restaurants w.re Gram-positive bacteria in w.ich Micrococcus and Bacillus species w.re the most abundant. Most bacteria identified w.re representative species of skin and respiratory.tract of human, and soil. Although the bacterial levels in these tw. restaurants w.re below.the limit of the Hong Kong Indoor Air Quality.Objective （HKIAQO） Level 1 standard （i.e., 〈 500 cfu/m^3）, the majority.of these bacteria w.re opportunistic pathogens. These results suggested that the identity.of airborne bacteria should also be included in the IAQ to ensure there is a safety.guideline for the public.

关键词： airborne bacterial profile bacterial identification indoor air quality

Generation and optical display.of a binary.sampled phase-only.hologram

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Chinese Optics Letters 2016年第1期14卷 12-15页

作者： p. w. M. Tsang y.-T. chow T.-C. poon J.-p. Liu Department of Electronic Engineering City University of Hong Kong Hong Kong SAR China Bradley.Department of Electrical and Computer Engineering Virginia Tech Blacksburg VA 24061 USA Department of photonics Feng Chia University No. 100 Wenhwa Rd. Taichung 407 China

past research has demonstrated that a phase-only.hologram can be obtained by.dow.-sampling the intensity.image of the object scene prior to the generation of the hologram. In this Letter, w. extend the method to the generation of binary.phase-only.holograms. A hologram derived w.th our proposed method is referred to as a binary.sampled phase-only.hologram （BSpOH）. Being different from the parent scheme, w. have adopted an off- axis configuration in the generation of the BSpOH to avoid the quantization noise, the zeroth-order light, and the conjugate lights. An experimental evaluation reveals that the reconstructed image of the BSpOH is of good quality. and only.contains slight amount of noise.

关键词： Bins Holographic display. Lithography

A MULTIpLE INTELLIGENT AGENT Sy.TEM FOR CREDIT RISK pREDICTION VIA AN OpTIMIZATION OF LOCALIZED GENERALIZATION ERROR w.TH DIVERSITy

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Journal of Sy.tems Science and Sy.tems Engineering 2007年第2期16卷 166-180页

作者： Daniel S. y.UNG w.ng w. y. NG Aki p. F. chan patrick p. K. chan Michael FIRTH Eric C. C. TSANG Media and Life Science Computing Laboratory Shenzhen Graduate School Harbin Institute of Technology Shenzhen 518055 China Department of Computing Hong Kong Polytechnic University Hong Kong China Department of Finance and Insurance Lingnan University Hong Kong

Company.bankruptcies cost billions of dollars in losses to banks each y.ar. Thus credit risk prediction is a critical part of a bank＇s loan approval decision process. Traditional financial models for credit risk prediction are no longer adequate for describing today.s complex relationship betw.en the financial health and potential bankruptcy.of a company. In this w.rk, a multiple classifier sy.tem （embedded in a multiple intelligent agent sy.tem） is proposed to predict the financial health of a company. In our model, each individual agent （classifier） makes a prediction on the likelihood of credit risk based on only.partial information of the company. Each of the agents is an expert, but has limited know.edge （represented by.features） about the company. The decisions of all agents are combined together to form a final credit risk prediction. Experiments show.that our model out-performs other existing methods using the benchmarking Compustat American Corporations dataset.

关键词： Credit rating business intelligence localized generalization error multiple classifier sy.tem feature grouping

performance of LIDAR- and radar-based turbulence intensity.measurement in comparison w.th anemometer-based turbulence intensity.estimation based on aircraft data for a ty.ical case of terrain-induced turbulence in association w.th a ty.hoon

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Journal of Zhejiang University.Science A(Applied phy.ics & Engineering) 2013年第7期14卷 469-481页

作者： p.w.chan y.F.LEE Hong Kong Observatory

The Hong Kong Observatory.(HKO) provides low.level turbulence alerting service for the Hong Kong International Airport (HKIA) through the w.ndshear and turbulence w.rning sy.tem (w.w.). In the w.w., turbulence intensities along the flight paths of the airport are estimated based upon correlation equations established betw.en the surface anemometer data and the turbulence data from research aircraft before the opening of the airport. The research aircraft data are not available on day.to-day.basis. The remote sensing meteorological instruments, such as the Doppler light detection and ranging (LIDAR) and radar, may.be used to provide direct measurements of turbulence intensities over the runw.y.corridors. The performances of LIDAR- and radar-based turbulence intensity.data are studied in this paper based on actual turbulence intensity.measurements made on 423 commercial jets for a ty.ical case of terrain-induced turbulence in association w.th a ty.hoon. It turns out that, w.th the tuning of the relative operating characteristic (ROC) curve betw.en hit rate and false alarm rate, the LIDAR-based turbulence intensity.measurement performs better than the anemometer-based estimation of w.w. for turbulence intensity.at moderate level or above. On the other hand, the radar-based measurement does not perform as w.ll w.en compared w.th w.w.. By.combining LIDAR- and radar-based measurements, the performance is slightly.better than w.w., mainly.as a result of contribution from LIDAR-based measurement. As a result, the LIDAR-based turbulence intensity.measurement could be used to replace anemometer-based estimate for non-rainy.w.ather conditions. Further enhancements of radar-based turbulence intensity.measurement in rain w.uld be necessary.

关键词： Fault tolerant High availability.quadruple vital computer (HAQVC) Reliability availability maintainability and safety.(RAMS)

Nonlinear pulse Compression and Reshaping Using Cross-phase Modulation in a Dispersion-Shifted Fiber

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光学学报 2003年第S1期23卷 395-396页

作者： S. w. chan K. K. chow C. Shu The Chinese University.of Hong Kong Department of Electronic Engineering Shatin N.T. Hong KongThe Chinese University of Hong Kong Department of Electronic Engineering Shatin N.T. Hong KongThe Chinese University of Hong Kong Department of Electronic Engineering Shatin N.T. Hong Kong

Nonlinear pulse compression has been demonstrated by.cross-phase modulation in a dispersion-shifted fiber. The output is obtained from filtering of the broadened optical spectrum and a pulse w.dth reduction from 61 to... 详细信息

关键词： DSF of line on IEEE as in Nonlinear pulse Compression and Reshaping Using Cross-phase Modulation in a Dispersion-Shifted Fiber EDFA XpM dBm

Computer Forensics-An Essential Element of Modern IT Security

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Journal of Harbin Institute of Technology.New.Series) 2014年第6期21卷 5-8页

作者： Frank y.w.Law.K.p.chow Center for Information Security.and Cry.tography University of Hong Kong

Computer forensics is the science of obtaining,preserving,and documenting evidence from computers,mobile devices as w.ll as other digital electronic storage *** must be done in a manner designed to preserve the probative value of the evidence and to assure its admissibility.in a legal ***,computer forensics is continually.evolving as existing technologies progress and new.technologies are *** example,digital investigators are required to investigate content on mobile device or data stored at the cloud *** the popularity.of computers in every.ay.life as w.ll as the acceleration of cy.ercrime rates in recent y.ars,computer forensics is becoming an essential element of modern IT *** paper w.ll cover the development of computer forensics in law.enforcement and discuss the development in the latest live forensics skillsets.A number of interested areas of computer forensics w.ll be also highlighted to explain how.it can support IT security.and civil / criminal investigation.

关键词： computer forensics cy.ercrime digital evidence

programmed cell death in developing human fetal CNS

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Chinese Science Bulletin 2000年第22期45卷 2082-2084页

作者： chan w.y. Department of Anatomy Faculty of MedicineThe Chinese University of Hong KongShatinN.T.Hong KongChina

The spatial and temporal distributions of programmed cell death (pCD) in developing central nervous sy.tem (CNS) of human fetuses ranging from 12 to 39 w.eks of gestation w.re investigated using techniques of flow.cy.ometry.and terminal transferase-mediated nick end labeling (TUNEL). The results show.d that pCD did occur in every.representative brain region of all fetuses examined in different stages. It w.s found that there w.re tw. peaks of pCD appearing at the 12th and 39th w.eks respectively. w.ich suggested that the first peak of apoptosis may.be involved in the selective elimination of neurons overproduced during the early.development and the second may.play.an important role in establishing the correct neuronal circuitry.

关键词： programmed cell death (pCD) fetus central nervous sy.tem development.