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A fully distributed robust optimal control approach for air-conditioning systems considering uncertainties of communication link in IoT-enabled building automation systems

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Energy and Built Environment

Energy and Built Environment 2024年第3期5卷 446-454页

作者： Wenzhuo Li Rui Tang Shengwei Wang Institute for Environmental Design and Engineering The BartlettUniversity College LondonUK Department of Building Environment and Energy Engineering The Hong Kong Polytechnic UniversityKowloonHong Kong research Institute for Smart Energy The Hong Kong Polytechnic UniversityKowloonHong Kong

Internet of Things(IoT)technologies are increasingly implemented in buildings as the cost-effective smart sens-ing infrastructure of building automation systems(BASs).They are also dispersed computing resources for novel distributed optimal control ***,wireless communication networks are critical to fulfill these tasks with the performance influenced by inherent uncertainties in networks,e.g.,unpredictable occurrence of link *** and hierarchical distributed approaches are vulnerable against link failure,while the robustness of fully distributed approaches depends on the algorithms *** study therefore proposes a fully distributed robust optimal control approach for air-conditioning systems considering uncertainties of com-munication link in IoT-enabled *** distributed algorithm is adopted that agents know their out-neighbors *** directly coordinate with the connected neighbors for global *** are conducted to test and validate the proposed approach by comparing with existing approaches,i.e.,the centralized,the hierarchical distributed and the fully distributed *** show that different approaches are vulnerable against to uncertainties of communication link to different *** proposed approach always guarantees the optimal control performance under normal conditions and conditions with link failures,verifying its high *** also has low computation complexity and high optimization efficiency,thus applicable on IoT-enabled BASs.

关键词： Multi-agent system Edge computing Air-conditioning system Internet of Things(IoT) Communication link failure

Directly predicting N2 electroreduction reaction free energy using interpretable machine learning with non-DFT calculated features

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Journal of Energy Chemistry 2024年第10期97卷 139-148页

作者： Yaqin Zhang Yuhang Wang Ninggui Ma Jun Fan Department of Materials Science and Engineering City University of Hong Kong Center for Advanced Nuclear Safety and Sustainable Development City University of Hong Kong Department of Mechanical Engineering City University of Hong Kong

Electrocatalytic nitrogen reduction to ammonia has garnered significant attention with the blooming of single-atom catalysts（SACs）,showcasing their potential for sustainable and energy-efficient ammonia ***,cost-effectively designing and screening efficient electrocatalysts remains a *** this study,we have successfully established interpretable machine learning（ML） models to evaluate the catalytic activity of SACs by directly and accurately predicting reaction Gibbs free *** models were trained using non-density functional theory（DFT） calculated features from a dataset comprising 90 graphene-supported *** results underscore the superior prediction accuracy of the gradient boosting regression（GBR） model for both Δg（N2→NNH） and ΔG（NH2→NH3）,boasting coefficient of determination（R2） score of 0.972 and 0.984,along with root mean square error（RMSE） of 0.051 and 0.085 eV,***,feature importance analysis elucidates that the high accuracy of GBR model stems from its adept capture of characteristics pertinent to the active center and coordination environment,unveilling the significance of elementary descriptors,with the colvalent radius playing a dominant ***,Shapley additive explanations（SHAP） analysis provides global and local interpretation of the working mechanism of the GBR *** analysis identifies that a pyrrole-type coordination（flag=0）,d-orbitals with a moderate occupation（Nd=5）,and a moderate difference in covalent radius(rTM-avenear 140 pm) are conducive to achieving high ***,we extend the prediction of activity to more catalysts without additional DFT calculations,validating the reliability of our feature engineering,model training,and design *** findings not only highlight new opportunity for accelerating catalyst design using non-DFT calculated features,but also shed light on the working mechanism of "black box" ML ***,the model provides valuable guidanc

关键词： Graphene Interpretable machine learning Nitrogen reduction Non-DFT features Single-atom catalyst

Predicting building ventilation performance in the era of an indoor air crisis

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Building Simulation 2023年第5期16卷 663-666页

作者： Yuguo Li Pan Cheng Li Liu Ao Li Wei Jia Nan Zhang Department of Mechanical Engineering The University of Hong KongPokfulamHong KongChina Faculty of Architecture The University of Hong KongPokfulamHong KongChina School of Architecture Tsinghua UniversityBeijingChina Beijing Key Laboratory of Green Built Environment and Energy Efficient Technology Beijing University of TechnologyBeijingChina

Background Coronavirus disease 2019(COVID-19)is caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2),which is continuing to *** alone has not completely controlled the COVID-19 pandemic,and infection with SARS-CoV-2—particularly with the omicron variant—continues to threaten human health and life and thus negatively affect economies worldwide.

关键词： acute respiratory alone

Optimal Selling Time in Stock Market over a Finite Time Horizon

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Acta Mathematicae Applicatae Sinica 2012年第3期28卷 557-570页

作者： S.C.P.YAM S.P.YUNG W.ZHOU The Chinese University of Hong Kong China The University of Hong Kong China

In this paper, we examine the best time to sell a stock at a price being as close as possible to its highest price over a finite time horizon [0, T], where the stock price is modelled by a geometric Brownian motion and the ＇closeness＇ is measured by the relative error of the stock price to its highest price over [0, T]. More precisely, we want to optimize the expression：V^＊=sup 0≤τ≤T E[Vτ/MT],where （Vt）t≥0 is a geometric Drownian motion with constant drift α and constant volatility σ 〉 0, Mt = max Vs 0≤a〈t is the running maximum of the stock price, and the supremum is taken over all possible stopping times 0 ≤ τ≤T adapted to the natural filtration （Ft）t≥0 of the stock price. The above problem has been considered by Shiryacv, Xu and Zhou （2008） and Du Toit and Peskir （2009）. In this paper we provide an independent proof that when α=1/ 2 σ^2 , a selling strategy is optimal if and only if it sells the stock either at the terminal time T or at the 1 2 moment when the stock price hits its maximum price so far. Besides, when α 〉1/2σ^2 , selling the stock at the terminal time T is the unique optimal selling strategy. Our approach to the problem is purely probabilistic and has been inspired by relating the notion of dominant stopping pr of a stopping time τ to the optimal stopping strategy arisen in the classical ＂Secretary Problem＂.

关键词： optimal Stopping stock selling buy and hold local time

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Gut Microbiome in Colorectal Cancer:Clinical Diagnosis and Treatment

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Genomics, Proteomics & Bioinformatics 2023年第1期21卷 84-96页

作者： Yali Liu Harry Cheuk-Hay Lau Wing Yin Cheng Jun Yu Institute of Digestive Disease and The Department of Medicine and Therapeutics State Key Laboratory of Digestive DiseaseLi Ka Shing Institute of Health SciencesCUHK Shenzhen Research InstituteThe Chinese University of Hong KongHong Kong Special Administrative Region 999077China

Colorectal cancer(CRC)is one of the most frequently diagnosed cancers and the leading cause of cancer-associated *** studies have shown that both genetic and environmental risk factors contribute to the development of *** metagenomic studies of CRC have identified gut dysbiosis as a fundamental risk factor in the evolution of colorectal *** enormous efforts and substantial progresses have been made in understanding the relationship between human gut microbiome and CRC,the precise mechanisms involved remain *** data have shown a direct causative role of the gut microbiome in DNA damage,inflammation,and drug resistance in CRC,suggesting that modulation of gut microbiome could act as a powerful tool in CRC prevention and ***,we provide an overview of the relationship between gut microbiome and CRC,and explore relevant mechanisms of colorectal *** next highlight the potential of bacterial species as clinical biomarkers,as well as their roles in therapeutic *** limiting the clinical translation of gut microbiome and strategies for resolving current challenges are further discussed.

关键词： Gut microbiome Colorectal cancer Diagnostic biomarker Immunotherapy Chemotherapy

Estimation of exponential growth rate and basic reproduction number of the coronavirus disease 2019 (COVID-19)in Africa

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Infectious Diseases of Poverty 2020年第4期9卷 60-65页

作者： Salihu S.Musa Shi Zhao Maggie H.Wang Abdurrazaq G.Habib Umar T.Mustapha Daihai He Department of Applied Mathematics Hong Kong Polytechnic UniversityHong KongChina Department of Mathematics Kano University of Science and TechnologyWudilNigeria JC School of Public Health and Primary Care Chinese University of Hong KongHong KongChina Shenzhen research Institute of Chinese University of Hong Kong ShenzhenChina Collage of Health Sciences Bayero UnuversityKanoNigeria Department of Mathematics Federal University DutseDutseNigeria

Background:Since the first case of coronavirus disease 2019(COVID-19)in Africa was detected on February 14,2020,the cumulative confirmations reached 15207 including 831 deaths by April 13,*** has been described as one of the most vulnerable region with the COVID-19 infection during the initial phase of the outbreak,due to the fact that Africa is a great commercial partner of China and some other EU and American *** result in large volume of travels by traders to the region more frequently and causing African countries face even bigger health threat during the COVID-19 ***,the fact that the control and management of COVID-19 pandemic rely heavily on a country's health care system,and on average Africa has poor health care system which make it more vulnerable indicating a need for timely intervention to curtail the *** this paper,we estimate the exponential growth rate and basic reproduction number(R0)of COVID-19 in Africa to show the potential of the virus to spread,and reveal the importance of sustaining stringent health measures to control the disease in ***:We analyzed the initial phase of the epidemic of COVID-19 in Africa between 1 March and 13 April 2020,by using the simple exponential growth *** examined the publicly available materials published by the WHO situation report to show the potential of COVID-19 to spread without sustaining strict health *** Poisson likelihood framework is adopted for data fitting and parameter *** modelled the distribution of COVID-19 generation interval(GI)as Gamma distributions with a mean of 4.7 days and standard deviation of 2.9 days estimated from previous work,and compute the basic reproduction ***:We estimated the exponential growth rate as 0.22 per day(95%CI:0.20-0.24),and the basic reproduction number,R0,as 2.37(95%CI:2.22-2.51)based on the assumption that the exponential growth starting from 1 March *** an R0 at 2.37,we quantif

关键词： COVID-19 Reproduction number Pandemic Statistical modelling

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High Sensitivity of Shotgun Metagenomic Sequencing in Colon Tissue Biopsy by Host DNA Depletion

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Genomics, Proteomics & Bioinformatics 2023年第6期21卷 1195-1205页

作者： Wing Yin Cheng Wei-Xin Liu Yanqiang Ding Guoping Wang Yu Shi Eagle S.H.Chu Sunny Wong Joseph J.Y.Sung Jun Yu State Key Laboratory of Digestive Disease Institute of Digestive Disease and The Department of Medicine and TherapeuticsLi Ka Shing Institute of Health SciencesShenzhen Research InstituteThe Chinese University of Hong KongHong Kong Special Administrative Region 999077China Lee Kong Chian School of Medicine Nanyang Technology UniversitySingapore 639798Singapore

The high host genetic background of tissue biopsies hinders the application of shotgun metagenomic sequencing in characterizing the tissue *** proposed an optimized method that removed host DNA from colon biopsies and examined the effect on metagenomic *** or mouse colon biopsies were divided into two groups,with one group undergoing host DNA depletion and the other serving as the *** DNA was removed through differential lysis of mammalian and bacterial cells before *** impact of host DNA depletion on microbiota was compared based on phylogenetic diversity analyses and regression *** host DNA enhanced bacterial sequencing depth and improved species discovery,increasing bacterial reads by 2.46±0.20 folds while reducing host reads by 6.80%±1.06%.Moreover,2.40 times more of bacterial species were detected after host DNA *** was confirmed from mouse colon tissues,increasing bacterial reads by 5.46±0.42 folds while decreasing host reads by 10.2%±0.83%.Similarly,significantly more bacterial species were detected in the mouse colon tissue upon host DNA depletion(P<0.001).Furthermore,an increased microbial richness was evident in the host DNA-depleted samples compared with non-depleted controls in human colon biopsies and mouse colon tissues(P<0.001).Our optimized method of host DNA depletion improves the sensitivity of shotgun metagenomic sequencing in bacteria detection in the biopsy,which may yield a more accurate taxonomic profile of the tissue microbiota and identify bacteria that are important for disease initiation or progression.

关键词： Gut microbiota Colon tissue Host DNAdepletion Shotgun metagenomic sequencing

The impact of COVID-19 vaccination campaign in Hong Kong SAR China and Singapore

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Infectious Disease Modelling 2023年第1期8卷 101-106页

作者： Boyu Yu Qiong Li Jing Chen Daihai He Department of Applied Mathematics Hong Kong Polytechnic UniversityHong KongChina BNU-HKBU United International College ZhuhaiChina

Background:Vaccination has been the most important measure to mitigate the COVID-19 *** vaccination coverage was relatively low in Hong Kong Special Administrative Region China,compared to Singapore,in early ***,if the two regions,Hong Kong(HK)and Singapore(SG),swap their vaccination coverage rate,what outcome would occur?Method:We adopt the Susceptible e Vaccinated e Exposed e Infectious e Hospitalized e Death-Recovered model with a time-varying transmission rate and fit the model to weekly reported COVID-19 deaths(the data up to 2022 Nov 4)in HK and SG using R package *** we obtain a reasonable fitting,we rerun our model with the estimated parameter values and swap the vaccination rates between HK and SG to explore what would ***:Our model fits the data *** reconstructed transmission rate was higher in HK than in SG in *** a higher vaccination rate as in SG,the death total reported in HK would decrease by 37.5%and the timing of the peak would delay by 3 *** a lower vaccination rate as in HK,the death total reported in SG would increase to 5.5-fold high with a peak 6 weeks earlier than the actual during the Delta variant ***:Vaccination rate changes in HK and SG may lead to very different *** is likely due that the estimated transmission rates were very different in HK and SG which reflect the different control policies and dominant *** of strong control measures,HK avoided large-scale community transmission of the Delta *** the high breakthrough infection rate and transmission rate of the Omicron variant,increasing the vaccination rate in HK will likely yield a mild(but significant)contribution in terms of lives *** in SG,lower vaccination coverage to the level of HK will be disastrous.

关键词： likely breakthrough impact

The genetic and epigenetic alterations in human hepatocellular carcinoma： a recent update

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Protein & Cell 2014年第9期5卷 673-691页

作者： Ming Liu Lingxi Jiang Xin-Yuan Guan Department of Clinical Oncology University of Hong Kong Hong Kong China

Hepatocellular carcinoma （HCC） is one of the most frequent human malignancies worldwide with very poor prognosis. It is generally accepted that the progression of HCC is a long-term process with accumulation of multiple genetic and epigenetic alterations, which further lead to the activation of critical oncogenes or inactivation of tumor suppressor genes. HCC is characterized with multiple cancer hallmarks including their ability to proliferate, anti-poptosis, invade, metastasis, as well as the emerging features such as stem cell properties and energy metabolic switch. The irreversible alterations at genetic level could be detected as early as in the pre-neoplastic stages and accumulate during cancer progression. Thus, they might account for the cancer initiating steps and further malignant transformation. In addition to genetic alterations, epigenetic alterations can affect the cancer transcriptome more extensively. Alterations in DNA methylation, histone modification, miRNAs, RNA editing, and IncRNAs might result in disrupted gene regulation networks and substantially contribute to HCC progression. In this review, the genetic and epigenetic alterations which significantly contribute to the malignant capabilities of HCC will be updated and summarized in detail. Further characterization of those critical molecular events might better elucidate the pathogenesis of HCC and provide novel therapeutic targets for treatment of this deadly disease.

关键词： hepatocellular carcinoma (HCC) cancerhallmarks genetic regulation epigenetic regulation,therapeutic targets HCC progression

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