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Antenatal anxiety in the first trimester: Risk factors and effects on anxiety and depression in the third trimester and 6-week postpartum

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Open Journal of Psychiatry 2013年第3期3卷 301-310页

作者： Chui Yi Chan Antoinette Marie Lee siu keung lam Chin Peng Lee Kwok Yin Leung Yee Woen Koh Catherine So Kum Tang Department of Obstetrics and Gynaecology LKS Faculty of Medicine The University of Hong Kong Hong Kong China Department of Obstetrics and Gynaecology Queen Elizabeth Hospital Hong Kong China Department of Psychiatry LKS Faculty of Medicine The University of Hong Kong Hong Kong China Department of Psychology National University of Singapore Singapore City Singapore

Objective: Anxiety is common among pregnant women. However, research attention in the area of reproductive mental health has mainly focused on postpartum depression in past decades. Given adverse outcomes of antenatal anxiety, there is an urgent need to fill the research gaps. The objectives of the present study were to determine the prevalence of antenatal anxiety symptoms and examine the risk factors and effects of anxiety symptoms in early pregnancy on anxiety and depressive symptoms in later pregnancy and early postpartum period. Methodology: A prospective longitudinal design with quantitative approach was adopted. A consecutive sample of 1470 Chinese pregnant women from hospitals in Hong Kong was invited to participate in the study and was assessed using standardized instruments on 3 time points including first and third trimesters of pregnancy and 6-week postpartum. Results: The results showed that 17.7% of pregnant women manifested anxiety symptoms in the first trimester of pregnancy. Single mothers, younger mothers, mothers who smoked before pregnancy and mothers who received low education level reported significantly higher levels of anxiety symptoms in the first trimester. Unwanted pregnancy, low self esteem, low marital satisfaction and perceived low social support were significant psychosocial risk factors for anxiety symptoms in the first trimester. Anxiety symptoms in the first trimester were independent predictors for anxiety symptoms in the third trimester ( QUOTE β = 0.26, t = 5.74, p < 0.001), however anxiety symptoms in the first trimester no longer significantly predicted anxiety and depressive symptoms in 6 weeks postpartum after adjusting for the effects of potential confounders. Discussions: The present study points to the need for greater research and clinical attention to antenatal anxiety given that antenatal anxiety is a prevalent problem and has serious impacts on maternal well-being. Such findings also contribute to the understanding of

关键词： Pregnancy Antenatal Anxiety Postpartum Anxiety and Depression

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Finite-Time Fuzzy Sliding Mode Control for Nonlinear Descriptor Systems

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IEEE/CAA Journal of Automatica Sinica 2021年第6期8卷 1141-1152页

作者： Zhixiong Zhong Xingyi Wang Hak-keung lam Key Laboratory of Information Processing and Intelligent Control Minjiang UniversityFuzhou 350121China College of Mechanical and Electronic Engineering Fujian Agriculture and Forestry UniversityFuzhou 350108China Department of Engineering King’s College LondonLondonWC2R 2LSUnited Kingdom

This article addresses the finite-time boundedness(FTB)problem for nonlinear descriptor ***,the nonlinear descriptor system is represented by the Takagi-Sugeno(T-S)model,where fuzzy representation is assumed to be appearing not only in both the state and input matrices but also in the derivative *** using a descriptor redundancy approach,the fuzzy representation in the derivative matrix is reformulated into a linear ***,we introduce a fuzzy sliding mode control(FSMC)law,which ensures the finite-time boundedness(FTB)of closed-loop fuzzy control systems over the reaching phase and sliding motion ***,by further employing the descriptor redundancy representation,the sufficient condition for designing FSMC law,which ensures the FTB of the closed-loop control systems over the entire finite-time interval,is derived in terms of linear matrix inequalities(LMIs).Finally,a simulation study with control of a photovoltaic(PV)nonlinear system is given to show the effectiveness of the proposed method.

关键词： Finite-time boundedness(FTB) fuzzy sliding mode control(FSMC) Takagi-Sugeno(T-S)fuzzy descriptor system

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Compensated methods for networked control system with packet drops based on compressed sensing

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Journal of Systems Engineering and Electronics 2021年第6期32卷 1539-1556页

作者： FAN Ruifeng YIN Xunhe LIU Zhenfei lam Hak keung Optoelectronic System Division North China Research Institute of Electro-OpticsChina Electronics Technology Group Corpora-tionBeijing 100015China School of Electronic and Information Engineering Beijing Jiaotong UniversityBeijing 100044China Department of Informatics Kings College LondonLondon WC2R 2NDUK

Due to unreliable and bandwidth-limited characteristics of communication link in networked control systems,the realtime compensated methods for single-output systems and multioutput systems are proposed in this paper based on the compressed sensing(CS)theory and sliding window technique,by which the estimates of dropping data packets in the feedback channel are obtained and the performance degradation induced by packet drops is ***,in order to reduce the cumulative error caused by the algorithm,the compensated estimates for single-output systems are corrected via the regularization term;considering the process of single-packet transmission,a new sequential CS framework of sensor data streams is introduced to effectively compensate the dropping packet on single-channel of multi-output systems;in presence of the medium access constraints on multi-channel,the communication sequence for scheduling is coupled to the algorithm and the estimates of the multiple sensors for multi-output systems are obtained via the regularization *** results illustrate that the proposed methods perform well and receive satisfactory performance.

关键词： networked control systems packet drop compensated method compressed sensing(CS)

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Non-conventional modeling of extreme significant wave height through random sets

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Acta Oceanologica Sinica 2014年第7期33卷 125-130页

作者： ZHANG Yi lam Jasmine siu Lee Division of Infrastructure Systems and Maritime Studies School of Civil and Environmental EngineeringN1-B1a-25 Nanyang Technological UniversitySingapore Division of Infrastructure Systems and Maritime Studies School of Civil and Environmental EngineeringN1-01b-43 Nanyang Technological UniversitySingapore

The analysis and design of offshore structures necessitates the consideration of wave loads. Realistic modeling of wave loads is particularly important to ensure reliable performance of these structures. Among the available methods for the modeling of the extreme significant wave height on a statistical basis, the peak over threshold method has attracted most attention. This method employs Poisson process to character- ize time-varying properties in the parameters of an extreme value distribution. In this paper, the peak over threshold method is reviewed and extended to account for subjectivity in the modeling. The freedom in selecting the threshold and the time span to separate extremes from the original time series data is incorpo- rated as imprecision in the model. This leads to an extension from random variables to random sets in the probabilistic model for the extreme significant wave height. The extended model is also applied to different periods of the sampled data to evaluate the significance of the climatic conditions on the uncertainties of the parameters.

关键词： offshore engineering extreme value distribution wave height peak over threshold randomset Pareto distribution

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Adaptive PID controller based on Q-learning algorithm

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CAAI Transactions on Intelligence Technology 2018年第4期3卷 235-244页

作者： Qian Shi Hak-keung lam Bo Xiao Shun-Hung Tsai Department of Informatics King’s College LondonBush HouseStrand Campus30 AldwychLondon WC2B 4BGUK Hamlyn Centre for Robotic Surgery Imperial College LondonLondon SW7 2AZUK Graduate Institute of Automation Technology National Taipei University of TechnologyTaipei 10608Taiwan

An adaptive proportional–integral–derivative(PID)controller based on Q-learning algorithm is proposed to balance the cart–pole system in simulation *** controller was trained using Q-learning algorithm and implemented the learned Q-tables to change the gains of linear PID controllers according to the state of the system during the control *** adaptive PID controller based on Q-learning algorithm was trained from a set of fixed initial positions and was able to balance the system starting from a series of initial positions that are different from the ones used in the training session,which achieved equivalent or even better performances in comparison with the conventional PID controller and the controller only uses Q-learning *** indicates the advantage of the adaptive PID controller based on Q-learning algorithm both in the generality of balancing the cart–pole system from a relatively wide range of initial positions and in the stabilisability of achieving smaller steady-state error.

关键词： Adaptive PID the controller

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ON EVALUATING THE RUN LENGTH PROPERTIES OF  CHARTS WITH ESTIMATED CONTROL LIMITS

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Journal of Systems Science & Complexity 2002年第4期15卷 436-444页

作者： LI Guoying YANG Chunyan siu-keung TSE Academy of Mathematics and systems Science Chinese

X charts with estimated control limits are commonly used in practice and treated as if the in-control process parameters were known. However, the former can behave quite differently from the latter. To understand the differences, it is necessary to study the run length distribution (RLD), its mean (ARL) and standard deviation (SDRL) of the X charts when the control limits are estimated. However, ARL and SDRL are integrals over an infinite region with a boundless integrand, the finiteness has not been proved in literature. In this paper, we show the finiteness and uniform integrability of ARL and SDRL. Furthermore, we numerically evaluate the ARL, SDRL and the RLD using number theory method. A numerical study is conducted to assess the performance of the proposed method and the results are compared with those given by Quesenberry and Chen.

关键词： Average run length uniform integrability numerical integration number theory method.

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Metabolites of Marine Fungus Aspergillus sp. Collected from Soft Coral Sarcophyton tortuosum

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Chemical Research in Chinese Universities 2010年第3期26卷 415-419页

作者： LI Hou-jin CAI Yong-tong CHEN Yun-yun lam Chi-keung LAN Wen-jian School of Chemistry and Chemical Engineering Sun Yat-sen University Guangzhou 510275 P. R. China School of Pharmaceutical Sciences Sun Yat-sen University Guangzhou 510006 P. R. China

Fungus Aspergillus sp., which was isolated from soft coral Sarcophyton tortuosum, was cultured in the GPY medium containing glucose 10 g/L, peptone 5 g/L, yeast extract 2 g/L, sea water 1 L, at pH=7.5. Four com pounds, 3,6-diisobutyl-2（1H）-pyrazinone（1）, 3-isobutyl-6-（1-hydroxy-2-methylpropyl）-2（1H）-pyrazinone（2）, 3-methoxy-4-methyl-2,4-dien-pentanoic acid（3） and penicillic acid（4） were obtained from the AcOEt extract of the culture broth. Their structures were elucidated mainly based on the NMR, HR-EI-MS and X-ray single crystal diffraction experimental data. Compound 3 is a new compound. Compound 1 was previously proposed to be the tautomer of flavacol（3,6-diisobutylpyrazin-2-ol, 5）. However, the evaluation of the NMR and X-ray single crystal diffraction experimental data permitted us to propose that compound 1 existed as amide form instead oftautomers. Compound 1 is stable both in solution and crystal due to strong intermolecular hydrogen bonds. Incidentally supplying anthracenone to the GPY medium with a dose of 100 mg/L, the yield of penicillic acid（4） in the culture broth of the strain Aspergillus sp. was increased dramatically from 6 mg/L to 57 mg/L.

关键词： Aspergillus sp. 3,6-diisobutyl-2(1H)-pyrazinone Penicillic acid Flavacol

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Mortality in relation to changes in physical activity in middle-aged to older Chinese:An 8-year follow-up of the Guangzhou Biobank Cohort Study

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Journal of Sport and Health Science 2021年第4期10卷 430-438页

作者： Yingyue Huang Chaoqiang Jiang Lin Xu Weisen Zhang Feng Zhu Yali Jin Kar keung Cheng Tai Hing lam School of Public Health Sun Yat-sen UniversityGuangzhou 510080China Molecular Epidemiology Research Centre Guangzhou No.12 HospitalGuangzhou 510620China School of Public Health the University of Hong KongHong Kong 999077China Institute of Applied Health Research University of BirminghamBirmingham B152TTUK

Background:Physical activity(PA)is generally *** from developed countries in the West have shown that maintenance of adequate PA or increasing PA are associated with lower mortality *** is unclear whether these associations apply to an older Chinese ***,we examined the changes in PA prospectively among a middle-aged and older Chinese population over an average of 4 years and explored their subsequent mortality ***:Metabolic equivalent scores of PA among participants in the Guangzhou Biobank Cohort Study were *** were divided into 3 groups related to PA level,and changes in PA were classified into 9 *** on vital status and causes of death from March 2008 to December 2012(the first repeated examination)until December 31,2017,was obtained via record linkage with the Death ***:Of 18,104 participants aged 61.21±6.85 years(mean±SD),1461 deaths occurred within 141,417 *** to participants who maintained moderate PA,those who decreased PA from moderate or high levels to a low level had increased risks for all-cause mortality(hazard ratio(HR)=1.47,95%confidence interval(95%CI):1.11-1.96).Participants who maintained a high level of PA(HR=0.83,95%CI:0.70-0.98)or increased PA from low to high levels(HR=0.71,95%CI:0.52-0.97)showed lower all-cause mortality *** who maintained low PA levels showed a higher all-cause mortality risk,whereas those who increased their PA levels showed a non-significantly lower *** results were found for cardiovascular disease ***:Even at an older age,maintaining a high PA level or increasing PA from low to high levels results in lower mortality risks,suggesting that substantial health benefits might be achieved by maintaining or increasing engagement in adequate levels of *** increased risk of maintaining a low PA level or decreasing PA to a low level warrants the attention of public health officials and clinic

关键词： All-cause mortality Cardiovascular disease mortality Change in physical activity

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基于模型的网络控制系统设计:切换控制的平均驻留时间法

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系统工程与电子技术 2016年第8期38卷 1899-1908页

作者：赵顺利尹逊和魏学业 lam Hak-keung 北京交通大学电子信息工程学院北京100044 伦敦大学国王学院信息系

利用平均驻留时间方法对基于模型的网络控制系统(model-based networked control system,MBNCS)进行了研究。MB-NCS由于能够在保证系统性能的前提下有效地减少系统对网络带宽的占用,自提出以来就受到了学者的广泛关注。首先总结了网络... 详细信息

利用平均驻留时间方法对基于模型的网络控制系统(model-based networked control system,MBNCS)进行了研究。MB-NCS由于能够在保证系统性能的前提下有效地减少系统对网络带宽的占用,自提出以来就受到了学者的广泛关注。首先总结了网络控制系统中常用的几种减少网络带宽占用的策略;其次,将基于模型的网络控制系统建模为切换系统,并在所建立的切换系统模型的基础上,利用平均驻留时间方法给出了使得此切换系统稳定的充分条件;最后,借助Lyapunov稳定性理论和线性矩阵不等式(linear matrix inequality,LMI)方法设计了使得此系统稳定的控制器,并且通过仿真验证了所提出方法的有效性。

关键词：基于模型的网络控制系统切换系统平均驻留时间 Lyapunov稳定性线性矩阵不等式

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Nine-year experience of doxorubicin-eluting beads chemoembolization for hepatocellular carcinoma

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Hepatobiliary & Pancreatic Diseases International 2016年第5期15卷 493-498页

作者： Alvin Ho-Kwan Cheung Colin siu-Chi lam Henry Shiu-Cheung Tam Tan-To Cheung Roberta Pang Ronnie Tung-Ping Poon Department of Surgery University of Hong Kong and Queen Mary Hospital

BACKGROUND: Chemoembolization with doxorubucin-eluting beads (DEB) has been used to treat hepatocellular carcinoma (HCC) since 2007. This study compared the efifcacy and sur-vival between transarterial chemoembolization (TACE) with DEB and conventional approach (cTACE) in HCC treatment. METHODS: This retrospective case-control study compared the overall survival and tumor response of HCC patients to cTACE (n=190) and DEB (n=143) by the reassessment of com-puted tomography and serum alpha-fetoprotein (AFP). Mul-tivariate analysis was used to determine the factors affecting tumor response. RESULTS: The median post-treatment to pre-treatment AFP level was 0.8 for a DEB session (n=258) and 1.0 for a cTACE session (n=452), showing a signiifcantly greater decrease in AFP after DEB (P80 months after the ifrst TACE session in the DEB group. CONCLUSION: DEB is a safe alternative to cTACE in HCC pa-tients with better therapeutic efifcacy.

关键词： doxorubicin-eluting beads transarterial chemoembolization hepatocellular carcinoma

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