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Sensitivity of Lagrangian Particle Tracking Based on a 3D Numerical Model

Journal of Modern Physics 2012年第12期3卷 1972-1978页

作者： dang huu chung Nguyen Thi Kieu Duyen Institute of Mechanics Vietnamese Academy of Science and Technology Hanoi Vietnam

The aim of the paper is to investigate in detail the sensitivity of particles displacement based on method of Lagrangian particle tracking in combination with a 3D Eulerian numerical model that was developed by the first author, namely FSUM. The characteristic parameters used for this research include the possibilities of random movement, settling velocity of solid particle, horizontal and vertical diffusion coefficients and condition of particle fixed with a constant distance under water surface. The first part is on the fluid flow model. It includes 3D Navier-Stokes equations together with the initial and boundary conditions that were numerically solved with the finite difference method and coded with FORTRAN 90/95 using parallel technique with OpenMP. A semi-Lagrangian treatment of the advective terms was used. The second part is related to Lagrangian particle tracking model and was solved with the fourth Runge-Kutta method. Model was applied for Strait of Johor and has been calibrated by using measured data on water level and velocity at one station. Eight cases of simulations with many different options were carried out. Through computed cases it shows that random term and settling velocity are very important factors for the behavior of particle trajectory. Although the random diffusion is minor in comparison with flow velocity, but it can rearrange the initial distribution of particles then the cluster of particles become more dispersive during the process of movement. In addition, introducing settling velocity of particle makes a big change on the trajectory of particle that becomes more suitable to sediment transport. The study gave a comprehensive picture on particle movement. The model also showed its possibilities of multiform applications in simulation and prediction for the different problems in practice.

关键词： 3D FSUM Model Random Walk Settling Velocity Numerical Simulations

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Prediction of the Local Scour at the Bridge Square Pier Using a 3D Numerical Model

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Open Journal of Applied Sciences 2014年第2期4卷 34-42页

作者： Nguyen Viet Thanh dang huu chung Tran Dinh Nghien University of Transport and Communication Hanoi Viet Nam Vietnam Academy of Science and Technology Hanoi Viet Nam

In this paper, the problem on local scour around a single square pier was studied by using both the numerical and physical models. The numerical model for the study is FSUM based on a finite-difference method to solve the Reynolds averaged Navier-Stokes equations (RANS) and the equations for suspended sediment concentration and bed morphology. The computed result was verified through data measured in the experimental flume with a sand bed. In general, the typical features of local scour around the pier were successfully simulated by FSUM, such as stream flow, bow flow, down flow, horseshoe vortex. The comparison between the computation and experiment data shows a quite good fitness. Both numerical model and experiment results show that the maximum scour depth occurs at two front edges of the pier. Although the computed result shows a little bigger scour depth in comparison with the measurement in the physical model, it still confirms the reliability of numerical model in some measure.

关键词： Numerical Modeling Experiment Bridge Square Pier Local Scour FSUM Model

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Dyna-QUF:Dyna-Q based univector field navigation for autonomous mobile robots in unknown environments

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Journal of Central South University 2013年第5期20卷 1178-1188页

作者： VIET Hoang-huu CHOI Seung-yoon chung Tae-choong Department of Computer Engineering Kyung Hee University

A novel approach was presented to solve the navigation problem of autonomous mobile robots in unknown environments with dense obstacles based on a univector field method. In an obstacle-free environment, a robot is ensured to reach the goal position with the desired posture by following the univector field. Contrariwise, the univector field cannot guarantee that the robot will avoid obstacles in environments. In order to create an intelligent mobile robot being able to perform the obstacle avoidance task while following the univector field, Dyna-Q algorithm is developed to train the robot in learning moving directions to attain a collision-free path for its navigation. Simulations on the computer as well as experiments on the real world prove that the proposed algorithm is efficient for training the robot in reaching the goal position with the desired final orientation.

关键词： Dyna-Q mobile robot reinforcement learning univector field

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An Ontology-Based Question Answering System for University Admissions Advising

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Intelligent Automation & Soft Computing 2023年第4期36卷 601-616页

作者： Thi Thanh Sang Nguyen dang huu Trong Ho Ngoc Tram Anh Nguyen School of Computer Science and Engineering International UniversityVNU-HCMCVietnam National UniversityHo Chi Minh CityVietnam

Question-Answer systems are now very popular and crucial to support human in automatically responding frequent questions in manyﬁ***,these systems depend on learning methods and training ***,it is necessary to prepare such a good dataset,but it is not an easy *** ontol-ogy-based domain knowledge base is able to help to reason semantic information and make effective answers given user *** study proposes a novel chatbot model involving ontology to generate efﬁcient responses automatically.A case study of admissions advising at the International University–VNU HCMC is taken into account in the proposed chatbot.A domain ontology is designed and built based on the domain knowledge of university admissions using Protégé.The Web user interface of the proposed chatbot system is developed as a prototype using *** includes a search engine reasoning the ontology and generat-ing answers to users’*** experiments are carried out to test how the system reacts to different ***ﬁrst experiment examines questions made from some templates,and the second one examines normal questions taken from frequent *** results have shown that the ontology-based chatbot can release meaningful and long *** results are analysed to prove the proposed chatbot is usable and promising.

关键词： Ontology chatbots answer-question systems domain knowledge base admissions advising

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Optical properties and dynamic process in metal ions doped on CdSe quantum dots sensitized solar cells

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Chinese Optics Letters 2018年第7期16卷 71-77页

作者： Ha Thanh Tung dang huu Phuc Institute of Research and Development Duy Tan University Theoretical Physics Research Group Advanced Institute of Materials Science Ton Duc Thang University Faculty of Applied Sciences Ton Duc Thang University

In recent years, the nanostructure for solar cells have attracted considerable attention from scientists as a result of a promising candidate for low cost devices. In this work, quantum dots sensitized solar cells with effective performance based on a co-sensitized Cd S∕Cd Se：Mn2＋（or Cu2＋） nanocrystal, which was made by successive ionic layer absorption and reaction, are discussed. The optical, physical, chemical, and photovoltaic properties of quantum dots sensitized solar cells were sensitized to Mn2＋and Cu2＋dopants. Therefore, the short current（JSC）of the quantum dot sensitized solar cells is boosted dramatically from 12.351 mA∕cm2 for pure Cd Se nanoparticles to 18.990 mA∕cm2 for Mn2＋ions and 19.915 mA∕cm2 for Cu2＋ions. Actually, metal dopant extended the band gap of pure Cd Se nanoparticles, reduced recombination, enhanced the efficiency of devices, and improved the charge transfer and collection. In addition, Mn2＋and Cu2＋dopants rose to the level of the conduction band of pure Cd Se nanoparticles, which leads to the reduction of the charge recombination, enhances the lightharvesting efficiency, and improves the charge diffusion and collection. The results also were confirmed by the obtained experimental data of photoluminescence decay and electrochemical impedance spectroscopy.

关键词： CdS Cu Mn FTO Optical properties and dynamic process in metal ions doped on CdSe quantum dots sensitized solar cells

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Univector field method-based multi-agent navigation for pursuit problem in obstacle environments

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Journal of Central South University 2017年第4期24卷 1002-1012页

作者： Le Pham Tuyen Hoang huu Viet Sang Hyeok An Seung Gwan Lee Dong-Han Kim Tae Choong chung Department of Computer Science and Engineering Kyung Hee University Yongin Gyeonggi 446-701 Korea Department of Information Technology Vinh University 182-Le Duan Vinh City Nghe An 461056 Vietnam Humanitas College Kyung Hee University Yongin Gyeonggi 446-701 Korea Department of Electronics and Radio Engineering Kyung Hee University Yongin Gyeonggi 446-701 Korea

The pursuit problem is a well-known problem in computer science. In this problem, a group of predator agents attempt to capture a prey agent in an environment with various obstacle types, partial observation, and an infinite grid-world. Predator agents are applied algorithms that use the univector field method to reach the prey agent, strategies for avoiding obstacles and strategies for cooperation between predator agents. Obstacle avoidance strategies are generalized and presented through strategies called hitting and following boundary(HFB); trapped and following shortest path(TFSP); and predicted and following shortest path(PFSP). In terms of cooperation, cooperation strategies are employed to more quickly reach and capture the prey agent. Experimental results are shown to illustrate the efficiency of the method in the pursuit problem.

关键词： pursuit problem predator agent prey agent univector field method multi-agent systems

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Anti-inflammatory effects of Solanum procumbens on a low dose complete Freund's adjuvant-induced arthritis rat model

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Asian Pacific Journal of Tropical Biomedicine 2023年第5期13卷 214-221页

作者： Xuan-Hai Do Trong Nghia Nguyen Thanh chung dang Thi Thanh Mai Nguyen Trung Nhan Nguyen Van Nhat Truong Do huu Tho Le Xuan Hai Nguyen Hoang Phu dang Giang-Linh Nguyen Dinh-Khanh Hoang Van-Quan Le Van-Mao Can Department of Practical and Experimental Surgery Vietnam Military Medical UniversityHanoi 10000Vietnam Department of Reconstructive and Microsurgery Craniofacial and Reconstructive Surgery CentreMilitary Central Hospital 108Hanoi 10000Vietnam Department of Anatomic Pathology Military Hospital 103Vietnam Military Medical UniversityHanoi 10000Vietnam Faculty of Chemistry University of ScienceVietnam National University Ho Chi Minh CityHo Chi Minh City 70000Vietnam Faculty of Medicine University of Medicine and PharmacyVietnam National UniversityHanoi 10000Vietnam Department of Ultrasound Imaging Diagnostics CentreMilitary Hospital 103Vietnam Military Medical UniversityHanoi 10000Vietnam Department of Functional Diagnostics Military Hospital 103Vietnam Military Medical UniversityHanoi 10000Vietnam Department of Pathophysiology Vietnam Military Medical UniversityHanoi 10000Vietnam

Objective:To investigate the anti-inflammatory and analgesic effects of Solanum procumbens on complete Freund’s adjuvantinduced arthritis rat ***:We isolated and identified five compounds in the ethanolsoluble Solanum procumbens extract(SP)with anti-inflammatory effects,including ursolic acid,β-sitosterol,hexadecanoic acid,cisvaccenic acid,and vanillic ***,we investigated the anti-inflammatory effects of SP on rheumatoid arthritis symptoms,including paw volumes,local temperatures,withdrawal latency,and mechanical withdrawal threshold at the hind paw and white blood cell(WBC)number from complete Freund’s adjuvant-induced arthritis rat ***:We have successfully established a complete Freund’s adjuvant-induced arthritis rat model at a low dose(1 mg/mL).SP extract significantly reduced paw volumes(P<0.05),prolonged withdrawal latencies(P<0.05),decreased local temperature,and increased the mechanical withdrawal threshold(P<0.05),but only SP extract at the dose of 300 mg/kg significantly decreased WBC ***:SP extract could be a potential medication candidate with anti-inflammatory effects for arthritis,but it requires further investigation into the mechanism of the SP and its effectiveness on other models as well as clinical trials.

关键词： Solanum procumbens Arthritis Anti-inflammation Complete Freund's adjuvant Rats

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A new species of the genus Leptolalax (Anura： Megophryidae) from southern Vietnam

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Zoological Research 2018年第3期39卷 185-201页

作者： Tang Van Duong dang Trong Do chung Dac Ngo Truong Quang Nguyen Nikolay A. Poyarkov Vietnam National Museum of Nature Vietnam Academy of Science and Technology Hanoi Vietnam Department of Vertebrate Zoology Biological FacultyLomonosov Moscow State University Moscow 119234 Russia Faculty of Natural Sciences Phu Yen University Tuy Hoa Phu Yen Vietnam College of Education Hue University Hue Vietnam Institute of Ecology and Biological Resources Vietnam Academy of Science and Technology Hanoi Vietnam Graduate University of Science and Technology Vietnam Academy of Science and Technology Cau Giay Hanoi Vietnam Joint Russian- Vietnamese Tropical Research and Technological Center Nghia Do Cau Giay Hanoi Vietnam

We describe a new species of megophryid frog from Phu Yen Province in southern Vietnam. Leptolalax macrops sp. nov. is distinguished from its congeners by a combination of the following morphological attributes：（1） body size medium （SVL 28.0-29.3 mm in three adult males, 30.3 mm in single adult female）; （2） supra-axillary glands present, creamy white; ventrolateral glands indistinct; （3） tympanum externally distinct; （4） dorsal skin roughly granular with larger tubercles, dermal ridges on dorsum absent; （5） rudimentary webbing present between fingers I-II and I1-111; rudimentary webbing between all toes; fingers and toes without dermal fringes; （6） in life ventral surface greyish-violet with white speckling; （7） supratympanic fold distinct, dark brown in life; （8） iris bicolored, typically golden in upper half, fading to golden green in lower half; （9） tibia short （TbL/SVL 0.44-0.45 in males）; and （10） eyes large and protuberant （ED/SVL 0.15-0.16 in males） From all congeners for which comparable sequences are available, the new species differs markedly in the 16S rRNA mitochondrial gene sequence （P-distance〉5.7%）. The new species is currently known only from montane evergreen tropical forests of Song Hinh District, Phu Yen Province, and M＇Drak District of Dak Lak Province at elevations of 470-630 m a.s.l.. We suggest the new species should be considered as Data Deficient following the IUCN＇s Red List categories. We also report a previously unknownLeptolalax mtDNA lineage from an evergreen tropica forest in the Hoa Thinh District of Phu Yen Province which may also represent an undescribed species.

关键词： Leptolalax macrops sp. nov. Phu YenProvince Dak Lak Province Southern coastal regionof Vietnam

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A Ray Tracing and Joint Spectrum Based Clustering and Tracking Algorithm for Internet of Intelligent Vehicles

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Journal of Communications and Information Networks 2020年第3期5卷 265-281页

作者： Luoyan Zhu Danping He Bo Ai Ke Guan Shuping dang Junhyeong Kim Heesang chung Zhangdui Zhong State Key Laboratory of Rail Traffic Control and Safety Beijing Jiaotong UniversityBeijing 100044China Beijing Engineering Research Center of High-speed Railway Broadband Mobile Communications Beijing 100044China CEMSE Division King Abdullah University of Science and Technology(KAUST)Thuwal 23955-6900Saudi Arabia Moving Wireless Network Research Section Electronics and Telecommunications Research Institute(ETRI)Daejeon 34129Republic of Korea

Driven by the rapid growth in information services provided by the Internet and the appearance of new multimedia applications,millimeter wave is foreseen as a key enabler towards the Internet of intelligent vehicles(IoIV)for urban traffic safety *** this regard,cluster-based channel modeling has become an important research topic in the realm of emergency *** fully understand the cluster-based channel model,a series of vehicle-to-infrastructure(V2I)channel simulations at 22.6 GHz are conducted by a three-dimensional ray tracing(RT)*** clustering and tracking algorithm is proposed and analyzed from three aspects by the obtained simulation *** multiple signal classification estimation spectrum is applied to restrain the influence of antenna sidelobes and identify targets at *** on the fundamentals,the clusters can be identified and subsequently tracked using the proposed *** impacts of antenna sidelobes,angle resolution of beam rotation,and non-line-of-sight propagation path on the performance of clustering and tracking are *** multi-component-level RT results are adopted as comparison benchmarks,which reflect the ground *** work aims to provide a full picture of the clustering characteristics for designing and analyzing emergency communication systems.

关键词： clustering and tracking algorithm Internet of intelligent vehicles(IoIV) millimeter-wave channel modeling ray tracing vehicle-to-infrastructure(V2I)communications

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Biomass accumulation of Panax vietnamensis in cell suspension cultures varies with addition of plant growth regulators and organic additives

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Asian Pacific Journal of Tropical Medicine 2017年第9期10卷 907-915页

作者： Tuan Tran Trong Dieu-Hien Truong Hoang Chinh Nguyen Dieu-Thai Tran Huyen-Trang Nguyen Thi Giap Do dang Ho Nguyen huu Plant Cell Technology Department Institute of Tropical BiologyVietnam Academy of Science and Technology9/621 Ha Noi HighwayLinh TrungThu DucHo Chi Minh CityViet Nam Faculty of Applied Sciences Ton Duc Thang University19 Nguyen Huu ThoTan PhongDistrict 7Ho Chi Minh CityViet Nam Genetic Engineering Department Institute of Tropical BiologyVietnam Academy of Science and Technology9/621 Ha Noi HighwayLinh TrungThu DucHo Chi Minh CityViet Nam

Objective: To evaluate the impact of plant growth regulators including kinetin(KN),benzyl adenine and naphthalene acetic acid, yeast extract and casein hydrolyzate on biomass accumulation of Vietnamese ginseng Panax vietnamensis(P. vietnamensis) in cell suspension ***: Cell suspension cultures were established from friable calluses derived from leaves and petioles of 3-year-old in-vitro P. vietnamensis plants. The cell suspension cultures were grown in Murashige and Skoog basal media supplemented with various concentrations of KN, benzyl adenine, naphthalene acetic acid, and yeast extract and casein ***: All tested factors generated an increase in the cell biomass of P. vietnamensis in suspension culture, but the impact of each varies depended on the factor type, concentration, and incubation period. Addition of 2.0 mg/L KN resulted in the largest biomass increase after 24 d,(57.0 ± 0.9) and(3.1 ± 0.1) mg/m L fresh and dry weight, respectively,whereas addition of benzyl adenine or naphthalene acetic acid produced optimum levels of Panax cell biomass at 1.0 and 1.5 mg/L, respectively. Addition of the elicitor yeast extract led to a 1.4–2.4 fold increase in biomass of P. vietnamensis, while addition of casein hydrolyzate enhanced biomass accumulation 1.8–2.6 ***: The addition of each factor causes significant changes in biomass accumulation of P. vietnamensis. The largest biomass accumulation is from cultures grown in MS media containing 2.0 mg/L KN for 24 d. The outcome of the present study provides new insights into the optimal suspension culture conditions for studies on the in vitro cell biomass production of P. vietnamensis.

关键词： Panax vietnamensis Plant cell suspension culture Plant regulators Yeast extract Casein hydrolyzate Biomass

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