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Sampling-efficient path planning and improved actor-critic-based obstacle avoidance for autonomous robots

Science China(Information Sciences) 2024年第5期67卷 197-214页

作者： Yefeng YANG Tao HUANG Tianqi WANG Wenyu YANG Han CHEN Boyang LI Chih-yung WEN Department of Aeronautical and Aviation Engineering The Hong Kong Polytechnic University Center for control Theory and Guidance Technology Harbin Institute of Technology School of Engineering The University of Newcastle Research Center for Unmanned Autonomous Systems The Hong Kong Polytechnic University

Autonomous robots have garnered extensive utilization in diverse fields. Among the critical concerns for autonomous systems, path planning holds paramount importance. Notwithstanding considerable efforts in its development over the years, path planning for autonomous systems continues to grapple with challenges related to low planning efficiency and inadequate obstacle avoidance response in a timely manner.This study proposes a novel and systematic solution to the path planning problem within intricate office buildings. The solution consists of a global planner and a local planner. To handle the global planning aspect, an adaptive clustering-based dynamic programming rapidly exploring random tree(ACDP-RRT) algorithm is proposed. ACDP-RRT effectively identifies obstacles on the map by leveraging geometric features.These obstacles are then represented as a collection of sequentially arranged convex polygons, optimizing the sampling region and significantly enhancing sampling efficiency. For local planning, a network decoupling actor-critic(ND-AC) algorithm is employed. The proposed ND-AC simplifies the local planner design process by integrating planning and control loops into a neural network(NN) trained via an end-to-end model-free deep reinforcement learning(DRL) framework. Moreover, the adoption of network decoupling(ND) techniques leads to an improved obstacle avoidance success rate when compared to conventional actor-critic(AC)-based methods. Extensive simulations and experiments are conducted to demonstrate the effectiveness and robustness of the proposed approach.

关键词： rapidly exploring random tree (RRT) adaptive clustering network decoupling actor critic (AC) path planning

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Influence of Aggregate Grain Size on the Formulation of Sand Concrete in the Construction Industry in Congo

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Geomaterials 2019年第4期9卷 81-96页

作者： Charlène Bassolokidi Nkengue Narcisse Malanda Gilbert Ganga Paul Louzolo-Kimbembe Guy Richard Mouengue National Higher Polytechnic School Marien Ngouabi University Brazzaville Congo office of control of buildings and public works Brazzaville Congo

The main objective of this study is to contribute to the optimization of the formulation of sand concretes and its valorisation according to natural sands from different quarries or extraction sites. Physical characteristics of natural sands have been determined and improved by the addition of crushing sand, taking into account the too fine elements of the sand. Four types of sand were used (Congo River, Djiri, Mfilou, crushed sand). The concrete formulations proposed from improved sands (30% crushed sand and 70% natural sand) reveal an increase in mechanical strength. Thus, it appeared that this improvement of the natural fine sands by the crushing sand has brought a clear increase in the maneuverability of the concretes and the physico-mechanical characteristics of nearly 50%, although this crushing sand has a sand equivalent value of less than 70%. These results augur well for the durability of structures in the construction industry in Congo.

关键词： Sand Formulation Recovery Materials Sand Concrete Physico-Mechanical Characteristics Construction

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Characterization of the Activity, Mineralogy and Correlations between the Properties of Clayey Soils

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Journal of Minerals and Materials Characterization and Engineering 2022年第5期10卷 410-428页

作者： Louis Ahouet Sorel Dzaba Brice Dublin Mbossa Elenga Sylvain Ndinga Okina Fabien T. Kimbatsa Higher Institute of Architecture Urbanism Building and Public Works Denis Sassou N’guesso University Brazzaville Congo Higher Polytechnic National School (ENSP) Marien Ngouabi University Brazzaville Congo Building and publics works control office (BCBTP) Brazzaville Congo

The activity is related to the mineralogy and geological history of clays. Soils with the same value of the liquidity limit or plasticity index can have very different characteristics depending on the amount and type of clay minerals. The methylene blue value characterizes the activity of the clays and reflects the surface activity. Ten inactive soils contain minerals (kaolinite, illite), these soils absorb little water. Two swelling soils have normal activity and are composed of minerals (kaolinite, illite, Montmorillonite). The relationships between clayey soils properties, their activities and between the activity and the liquidity limit are defined. The correlations obtained are linear fit and exponential and sigmoidal fits. The correlations obtained with a coefficient of determination of R2 (0.859 - 0.999) can be used to characterize and predict certain parameters of fine-grained soils as a function of clay content.

关键词： Activity Specific Surface Area Cation Exchange Capacity Mineralogy Atterberg Limit

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Exploring the association of paid sick leave with healthcare utilization and health outcomes in the United States:a rapid evidence review

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Global Health Journal 2023年第1期7卷 9-17页

作者： Suhang Song Brian H.Calhoun James E.Kucik Kristin J.Konnyu Renata Hilson Policy Research Analysisand Development OfficeOffice of the Associate Director for Policy and StrategyUS Centers for Disease Control and PreventionAtlantaGA 30329USA The Oak Ridge Institute for Science and Education Oak RidgeTN 37830USA Department of Health Policy and Management College of Public HealthUniversity of GeorgiaAthenGA 30602USA Center for Evidence Synthesis in Health School of Public HealthBrown UniversityProvidence RI02912USA

Objective:Paid sick leave(PSL)laws mandate employers give workers paid time off when they are sick or injured.This current study aims to examine whether access to PSL is associated with healthcare utilization and health outcomes and to summarize the types of utilization and outcomes which have been reported to be associated with PSL.Methods:We conducted a rapid evidence review.Our search of seven databases,including Medline,Embase,PsycINFO,Cochrane Library,CINAHL,Scopus,and JSTOR,on September 21,2020,identified 757 studies,30 of which were retained.Results:Previous evidence is mostly provided by cross-sectional studies with survey data.In this study,evidence suggests that PSL is significantly associated with some types of healthcare utilization and health outcomes.In terms of healthcare utilization,findings indicate PSL is associated with an increase in the use of some preventive sendees and a decrease in the use of emergency care;while findings are mixed regarding associations of PSL with health provider visits and the use of mammograms and pap smears.As for health outcomes,findings suggest PSL is associated with improved mental and self-rated health,decreased incidence of influenza-like illness,and lower occupational injuries and mortality rates.Conclusion:PSL may be an effective tool in improving some healthcare utilization and health outcomes.Future research could help identify mechanisms through which PSL access works and identify what policy components lead to better outcomes.

关键词： Paid sick leave Healthcare utilization Health outcomes Rapid evidence revie

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Geotechnical Characterization of Termite Mound Soils of Congo

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Open Journal of Civil Engineering 2022年第3期12卷 370-389页

作者： Louis Ahouet Mondésire Odilon Ngoulou Sylvain Ndinga Okina Sorel Dzaba Higher Institute of Architecture Urbanism Building and Public Works Denis Sassou Nguesso University Brazzaville Congo Laboratory of Materials and Energies (LME) Faculty of Sciences and Technics Marien Ngouabi University Brazzaville Congo Higher Polytechnic National School (ENSP) Marien Ngouabi University Brazzaville Congo Building and publics works control office (BCBTP) Brazzaville Congo

This study is to determine the activities and correlations in the fundamental properties of the termite mounds soils Cubitermes spp and Macrotermes sp. The Intrinsic properties depend on the mineralogy, organic composition and texture of soil. Grain size, Atterberg limits and soil blue values are geotechnical properties that were used to characterize the two soils. On the basis of the geotechnical properties, specific surface area, cation exchange capacity, relative activity, surface activity and soil activity were determined. The correlations obtained in the intrinsic soil properties are linear and polynomial fits. Indeed, the relationship between the plasticity index and the blue value of a soil on the one hand and between the specific surface area and the cation exchange capacity on the other hand, is a linear fit for all soils in general. The relationship between plasticity index and specific surface area is a linear fit for the soils (C, M). Correlations in intrinsic soil properties that have a coefficient of determination close to 1 can be used in geotechnical engineering to predict one of the two desired parameters.

关键词： Activity Relative Activity Surface Activity Cation Exchange Capacity Specific Surface Termite Mound Soil

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Concrete Formulation Study for Informal and Semi-Informal Construction Sectors

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Open Journal of Civil Engineering 2019年第1期9卷 57-79页

作者： Narcisse Malanda Paul Louzolo-Kimbembe Louis Ahouet Jarlon Brunel Makela Guy-Richard Mouengue National Polytechnic High School Marien Ngouabi University Brazzaville Congo Normal High School Marien Ngouabi University Brazzaville Congo Building and public works control office Brazzaville Congo

The present work consisted in carrying out a study on the effective formulation of concrete for an optimal resistance to compression (fc28) between 20 and 30 MPa for the sites animated by the actors of the informal and semi-informal sectors of the construction. Studies have been carried out on projects under construction, by taking samples of fresh concrete in order to evaluate their real compressive strengths. These surveys show that there is a problem in the concrete formulation, as nearly 2/3 of the results show the lack of technical knowledge on concrete formulation practices. Indeed, on eight sites surveyed and whose fresh concrete samples were taken, only two sites (7 and 8) report fairly consistent results. Their 28-day compressive strength values are respectively 35.36 and 22.18 MPa. In addition, various formulations proposed with aggregates from different quarries or extracts from the bed of the Congo River, were determined in the laboratory. This study allowed us to obtain fairly objective results overall, which is characteristic of concretes of required quality. Of the six (06) formulation proposals, average resistances of 19.6 MPa at 07 days and 25.28 MPa at 28 days were obtained. These results at 28 days are in the range of 20 to 30 MPa, set as objective in this study. These formulations can be a reliable source for concrete manufacturers in these construction sectors. Similarly, the statistical study based on principal component factor analysis tests has shown that the most appropriate formulation, in terms of mechanical resistance, is that proposed with sand extracted from the Congo River (formulation 3). This is justified by the fact that this sand is consistent and has a good granular distribution.

关键词： Formulation Concretes Aggregates Cement Physico-Mechanical Characteristics Informal and Semi-Formal Sectors

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Severe acute hepatitis of unknown causes in children–Current findings,questions,opinions,and recommendations,a mini-review

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Pediatric Investigation 2022年第3期6卷 211-218页

作者： Getu Zhaori Editorial office Pediatric InvestigationBeijing Children’s HospitalCapital Medical UniversityNational Center for Children’s HealthBeijingChina

Since October 2021 in Alabama,the United States,and March 2022 in central Scotland,the United Kingdom,the number of cases of severe acute hepatitis of unknown etiology/causes in children was found to increase,and the total number of cases has reached 920 worldwide by June 22 this year,45 cases(5%)required liver transplantation,and 18 cases(2%)died according to World Health Organization(WHO).To understand the basic characteristics of this disease/syndrome,a literature search was performed at PubMed,websites of WHO,UK Health Security Agency,and US and European Centers for Disease control and Prevention,and more than 20 reports were enrolled as references for this review.The main clinical manifestations are anorexia,vomiting,fatigue,jaundice,and so forth.Most of the cases seemed to have a self-limited course of the disease,about 6%of cases may develop life-threatening acute liver failure.The disease seems to be transmissible from person to person.Human adenovirus was detected in up to 75%of cases,but this virus seems not to be the only and major etiologic agent,other cofactors probably are involved.Researchers proposed many hypotheses concerning the etiology and pathogenesis,and many important works and studies are ongoing.This mini-review is aimed at summarizing,reviewing,and further understanding the characteristics of the disease,raising some clinically relevant questions,and trying to discuss some questions that may be related to the treatment of the disease for consideration.

关键词： Acute liver failure Children Severe acute hepatitis of unknown causes

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REVIEW AND PROSPECTS OF HYDROLOGICAL COMPONENT DEVELOPMENT OF ESCAP/WMO TYPHOON COMMITTEE

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Tropical Cyclone Research and Review 2018年第1期7卷 11-22页

作者： JINPING LIU YOSHIO TOKUNAGA HYOSEOB CHO JINXING WANG ESCAP/WMO Typhoon Committee Secretariat International Centre for Water Hazard and Risk Management Public Works Research Institute Han River Flood control office Ministry of Land Infrastructure and Transport Water Information Center Ministry of Water Resources

Hydrological Component has been one of three essential parts of ESCAP/WMO Typhoon Committee.The Working Group on Hydrology(WGH)established at TC 33rd Session in 2000 is the first working group among three basic components of the Committee,which has been repeatedly recognized as the most active component in the Committee who has integrated conducted successfully a number of cooperation projects and integrated actions among Members.In the past decade,WGH has implemented wide range activities under the framework of Strategic Plan of the Committee.The achievement of those cooperation projects played very important roles in promoting the capacity building on hydrological monitoring,forecasting and early warning among Members.This paper introduced the Term of Reference for WGH and its high priorities,and summarized the activities conducted in recent decade.The paper also reviewed the progresses in TC Members on hydrological observation and monitoring network,hydrological data collection and transmission,hydrological information and forecasting,and establishment of flood forecasting system.The paper also pointed out the development direction and the area to be enhanced for hydrological component in future,including:(1)application of QPE/QPF in flood forecasting and establishment of the coupled hydro-meteorological modeling;(2)development of impact-based,risk-based and community-based flood forecasting and warning system,including storm surge,urban flood,sediment disaster(flash flood,landslide and mudflow);and(3)application of internet of things(IOT),big data,cloud computing,and mobile internet in flood monitoring,forecasting and early warning,and better response,particularly in flood inundation mapping and QPE/QPF products application.

关键词： Typhoon Committee Hydrological Component development review prospect

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Associated risk factors of knee osteoarthritis： a population survey in Taiyuan, China

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Chinese Medical Journal 2006年第18期119卷 1522-1527页

作者： ZENG Qing-yu ZANG Chang-hai LI Xiao-feng DONG Hai-yuan ZHANG Ai-lian LIN Ling Department of Rheumatology First Affiliated Hospital of Shantou University Medical College Shantou 515041 China Department of Rheumatology Second Hospital of Shanxi Medical University Taiyuan 030001 China Editorial office of Chinese Journal of Rheumatology Taiyuan 030013 China School of public Health Shanxi Medical University Taiyuan 030001 China

Background Since knee osteoarthritis （KOA） is one of the common diseases, identification of its associated risk factors is of preventive significance. This investigation was designed to investigate the prevalence of KOA in Taiyuan, and identify the associated risk factors of KOA. Methods A population sample was surveyed of 2188 adults aged from 35 to 64 years, living in 6-story buildings without elevators. The protocol of Asia Pacific League of Associations for Rheumatology （APLAR） Community Oriented Program for control of Rheumatic Diseases （COPCORD） core questionnaire was implemented. The data on knee pain and KOA were collected and analyzed. Variables such as sex, age, body mass index （BMI）, waist circumference （WC）, education level, and smoking history, were included in binary logistic regression model for further analysis. Results The prevalence rates of knee pain and KOA were 13.6% and 10.9%, respectively, significantly higher than those in Shantou of south China and similar to those in Beijing of north China. The prevalence of KOA was significantly higher in women than in men （18.3% versus 8.7% and 15.1% versus 6.3%）, with a tendency of increase with age. The prevalence was increased more obviously in women after 40 years old and in men after 45 years old. BMI in KOA group was significantly higher than that in non-KOA group. Binary Logistic regression revealed that age, sex, and BMI were significantly associated with KOA, whereas no significant correlation was seen between KOA and other factors such as climbing stairs, WC, time length of occupation service, education level, smoking history and religious belief. Conclusion Geography, age, sex, and BMI might be the risk factors of KOA, but climbing stairs, WC, time length of occupation service, education level, smoking history and religious belief are not correlated with KOA. Prevention of KOA should be initiated before the middle-age, especially in female adults, and weight control is necessary. Other factors might also contribute to the development o

关键词： osteoarthritis, knee epidemiology risk factors

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Prevalence of Opportunistic Pathogens and Diversity of Microbial Communities in the Water System of a Pulmonary Hospital

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Biomedical and Environmental Sciences 2020年第4期33卷 248-259页

作者： TANG Wei MAO Yu LI Qiu Yan MENG Die CHEN Ling WANG Hong ZHU Ren ZHANG Wei Xian State Key Laboratory for Pollution control and Resource Reuse College of Environmental Science and EngineeringTongji UniversityShanghai 200092China Department of In fection control Shanghai Pulmonary HospitalTongji UniversityShanghai 200433China Shanghai Institute of Pollution control and Ecological Security Shanghai 200092China

Objective Our objective was to investigate the occurrence of opportunistic pathogens and characterize the bacterial community structures in the water system of a pulmonary hospital.Methods The water samples were collected from automatic and manual faucets in the consulting room,treatment room,dressing room,respiratory ward,and other non-medical rooms in three buildings of the hospital.Quantitative polymerase chain reaction was used to quantify the load of several waterborne opportunistic pathogens and related microorganisms,including Legionella spp.,Mycobacterium spp.,and M.avium.Illumina sequencing targeting 16 S r RNA genes was performed to profile bacterial communities.Results The occurrence rates of Legionella spp.,Mycobacterium spp.,and M.avium were 100%,100%,and 76%,respectively in all samples.Higher occurrence rates of M.avium were observed in the outpatient service building(building 1,91.7%)and respiration department and wards(building 2,80%)than in the office building(building 3),where no M.avium was found.M.avium were more abundant in automatic faucets(average 2.21×10~4 gene copies/L)than in manual faucets(average 1.03×10~4 gene copies/m L)(P<0.01).Proteobacteria,Actinobacteria,Bacteroidetes,Cyanobacteria,Firmicutes,and Acidobacteria were the dominant bacterial phyla.Disinfectant residuals,nitrate,and temperature were found to be the key environmental factors driving microbial community structure shifts in water systems.Conclusion This study revealed a high level of colonization of water faucets by opportunistic pathogens and provided insight into the characteristics of microbial communities in a hospital water system and approaches to reduce risks of microbial contamination.

关键词： Opportunistic pathogen Microbial community Hospital water system Mycobacterium avium

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