VNU-UET Repository: No conditions. Results ordered -Date Deposited. 2021-01-20T01:03:52ZEPrintshttps://eprints.uet.vnu.edu.vn/images/sitelogo.pnghttps://eprints.uet.vnu.edu.vn/eprints/23172012021-01-06T02:44:08Z2021-01-06T02:44:08Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/4364This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/43642021-01-06T02:44:08ZImpact of blast and mechanical loads on the shear deformable stiffened sandwich plate with an auxetic core layer in thermal environmentNgoc Thinh PhamDinh Quang Vuquangvd2510@gmail.comThi Thuy Anh Vuanhvutt@vnu.edu.vnDinh Duc Nguyenducnd@vnu.edu.vn2021-01-06T02:43:57Z2021-01-06T02:43:57Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/4363This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/43632021-01-06T02:43:57ZNonlinear dynamic response and vibration of imperfect eccentrically stiffened sandwich third-order shear deformable FGM cylindrical panels in thermal environmentshis study follows an analytical approach to investigate the nonlinear dynamic response and vibration of eccentrically stiffened sandwich functionally graded material (FGM) cylindrical panels with metal–ceramic layers on elastic foundations in thermal environments. It is assumed that the FGM cylindrical panel is reinforced by the eccentrically longitudinal and transversal stiffeners and subjected to mechanical and thermal loads. The material properties are assumed to be temperature dependent and graded in the thickness direction according to a simple power law distribution. Based on the Reddy’s third-order shear deformation shell theory, the motion and compatibility equations are derived taking into account geometrical nonlinearity and Pasternak-type elastic foundations. The outstanding feature of this study is that both FGM cylindrical panel and stiffeners are assumed to be deformed in the presence of temperature. Explicit relation of deflection–time curves and frequencies of FGM cylindrical panel are determined by applying stress function, Galerkin method and fourth-order Runge-Kutta method. The influences of material and geometrical parameters, elastic foundations and stiffeners on the nonlinear dynamic and vibration of the sandwich FGM panels are discussed in detail. The obtained results are validated by comparing with other results in the literature.Dinh Duc Nguyenducnd@vnu.edu.vnDuc Tuan NgoTran PhuongQuoc Quan TranVan Thanh Nguyen2021-01-06T02:43:47Z2021-01-06T02:43:47Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/4361This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/43612021-01-06T02:43:47ZNonlinear post-buckling and vibration of 2D penta-graphene composite platesThe newly developed penta-graphene is a two-dimensional (2D) carbon allotrope with promising mechanical properties. This paper investigates the nonlinear post-buckling and vibration of imperfect three-dimensional penta-graphene composite plates resting on elastic foundations and subjected to uniform external pressure and axial compressive load. The elastic constants of the single-layer penta-graphene are fully determined by the density functional theory by fitting the equation of strain energy to the density functional theory energy. Specifically, the elastic constant C66 which has not been considered by other authors is also determined. The motion and compatibility equations are derived based on the classical plate theory taking into account von Karman geometrical nonlinearity, initial geometrical imperfection and Pasternak type elastic foundations. For nonlinear post-buckling, the Bubnov–Galerkin method is applied to obtain the load–deflection amplitude curves while the Runge–Kutta method and harmonic balance method are used to obtain the deflection amplitude–time curves and the amplitude–frequency curves for nonlinear vibration. Numerical results show the effects of geometrical parameters, initial imperfection and elastic foundations on the nonlinear post-buckling and vibration of the imperfect 2D penta-graphene plates. The present results are also compared to others to validate the accuracy of the applied method and approach.Dinh Duc Nguyenducnd@vnu.edu.vnTien Lam PhamQuoc Quan TranMinh Quang PhamVan Quyen Nguyen2021-01-06T02:43:39Z2021-01-06T02:43:39Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/4360This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/43602021-01-06T02:43:39ZNonlinear vibration of FGM moderately thick toroidal shell segment within the framework of Reddy’s third order-shear deformation shell theoryNonlinear vibration and dynamic response of functionally graded moderately thick toroidal shell segments resting on Pasternak type elastic foundation are investigated in this paper. Functionally graded materials are made from ceramic and metal, and the volume fraction of constituents are assumed to vary through the thickness direction according to a power law function. Reddy’s third order shear deformation, von Karman nonlinearity, Airy stress function method and analytical solutions are used to derive the governing equations. Galerkin method is used to convert the governing equation into nonlinear differential equation, then the explicit expressions of natural frequencies and nonlinear frequency–amplitude relations are obtained. Using Runge–Kutta method, the nonlinear differential equation of motion is solved, and then nonlinear vibration and dynamic response of shells are analyzed. The effects of temperature, material and geometrical properties, and foundation parameters on nonlinear vibration and dynamic characteristics are investigated and discussed in detail.Minh Vuong PhamDinh Duc Nguyenducnd@vnu.edu.vn2021-01-06T02:43:28Z2021-01-06T02:43:28Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/4359This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/43592021-01-06T02:43:28ZEffect of eccentrically oblique stiffeners and temperature on the nonlinear static and dynamic response of S-FGM cylindrical panelsThis work aims to study the effect of obique stiffeners on the nonlinear static and dynamic buckling behaviors of S-FGM cylindrical panels based on the classical shell theory (CST) with the geometrical nonlinearity in von Kármán Donnell sense. The dynamic critical buckling load is obtainted by Budiansky-Roth criterion. The cylindrical panels are reinforced by oblique stiffeners on the top layer, and supported by elastic foundations on the bottom layer. Numerical results are given to evaluate effects of inhomogeneous, dimensional parameters, temperature increment, compressive pressure, oblique angles of stiffeners, the imperfection of original shape, and elastic foundations to the nonlinear static and dynamic response of S-FGM cylindrical panels in the thermal environment.Dinh Duc Nguyenducnd@vnu.edu.vnSeung-Eock KimTuan Manh DuongDinh Nguyen Phamnguyenpd@vnu.edu.vn2021-01-06T02:43:14Z2021-01-06T02:43:14Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/4358This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/43582021-01-06T02:43:14ZFree vibration of cracked FGM plates with variable thickness resting on elastic foundationsMinh Phuc PhamTuan Manh DuongDinh Duc Nguyenducnd@vnu.edu.vn2021-01-06T02:43:02Z2021-01-06T02:43:02Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/4354This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/43542021-01-06T02:43:02ZEnhanced nodal gradient finite elements with new numerical integration schemes for 2D and 3D geometrically nonlinear analysisThe consecutive-interpolation procedure (CIP) has been recently proposed as an enhanced technique for traditional finite element method (FEM) with various desirable properties such as continuous nodal gradients and higher accuracy without increasing the total number of degrees of freedom (DOFs). It is common knowledge that linear finite elements, e.g., four-node quadrilateral (Q4) or eight-node hexahedral (HH8) elements, are not highly suitable for geometrically nonlinear analysis. The elements with quadratic interpolation functions have to be used instead. In this paper, the CIP-enhanced four-node quadrilateral element (CQ4), and the CIP-enhanced eight-node hexahedral element (CHH8), are for the first time extended to investigate geometrically nonlinear problems of two- (2D) and three-dimensional (3D) structures. To further enhance the efficiency of the present approaches, novel numerical integration schemes based on the concept of mid-point rules, namely element mid-points (EM) and element mid-edges (EE) are integrated into the present CQ4 element. For CHH8, the 3D-version of EM (namely 3D-EM) and the element mid-faces (EF) scheme are investigated. The accuracy and computational efficiency of the two novel quadrature schemes in both regular and irregular (distorted) meshes are analyzed. Numerical results indicate that the new integration approaches perform more efficiently than the well-known Gaussian quadrature while gaining equivalent accuracy. The performance of the CIP-enhanced elements, which is examined through numerical experiments, is found to be equivalent to that of quadratic Lagrangian finite element counterparts, while having the same discretization with that by the linear finite elements. In addition, we also apply the present CQ4 and CHH8 elements associated with different numerical integration techniques to nearly incompressible materials.Dinh Du NguyenMinh Ngoc NguyenDinh Duc Nguyenducnd@vnu.edu.vnRungamornrat JaroonQuoc Tinh Bui2020-12-31T02:00:05Z2020-12-31T02:00:05Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/4353This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/43532020-12-31T02:00:05ZQuy trình kiểm tra trùng lặp trong nhóm văn bảnDinh Hieu Vohieuvd@vnu.edu.vnNgọc Sơn NguyễnMinh Tuấn TrầnVăn Sơn Nguyễn2020-12-31T01:59:52Z2020-12-31T01:59:52Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/4352This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/43522020-12-31T01:59:52ZCảm biến khí O2 ứng dụng trong ôtôTruong Giang NguyenNgoc Ha NgoNgoc Khai NguyenDinh Tuan Phamtuanpd@vnu.edu.vnThi Hien HoangTruong Giang Ho2020-12-31T01:56:47Z2020-12-31T01:56:47Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/4350This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/43502020-12-31T01:56:47ZTÌNH TRẠNG PIN LƯU TRỮ (LiFePO4) SỬ DỤNG TRONG ĐÈN BÁO HIỆU
ĐƯỜNG THỦY NỘI ĐỊAPin Li-ion LiFePO4 được dùng phổ biến trong đèn báo hiệu đường thủy nội địa ở
Việt Nam do giá thành rẻ, và hiệu quả trong hệ thống đèn sử dụng nguồn năng lượng pin mặt trời và chiếu sáng LED. Tuy vậy, hiện tại đèn báo hiệu dạng này có thời gian sống khá thấp so với thời gian sống thông thường của pin LiFePO4. Trong bài báo này, chúng tôi trình bày tình trạng và một số tham số có thể ảnh hưởng làm giảm tuổi thọ hoạt động của loại pin LiFePO4 dùng trong hệ thống đèn báo hiệu đường thủy nội địa. Các tham số điều kiện môi trường hoạt động như độ ẩm, nhiệt độ, ánh sáng và quá trình sạc/xả được cho là nguyên nhân chính tác động đến thời gian sống của pin trong các đèn báo hiệu.Truong Giang Nguyenntgiang@utc.edu.vnSy Hieu NguyenTruong Giang HoNgoc Khai NguyenDinh Tuan Phamtuanpd@vnu.edu.vnThi Hoa Nguyennthoaly@utc.edu.vn2020-12-31T01:54:55Z2020-12-31T01:54:55Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/4349This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/43492020-12-31T01:54:55ZLand-Cover Mapping from Sentinel Time-Series Imagery on the Google Earth Engine: A Case Study for HanoiOver the past decade, satellite image processing is an overwhelming bulk of work. Recently, with rapid development in information technology, Google released Google Earth Engine (GEE), which is a powerful cloud computing platform, to help to improve the performance of geospatial big data archives and processing. In this study, we deployed a machine learning model to evaluate the capability of time series Sentinel imagery (Sentinel 2 A/B and Sentinel 1A) in landcover mapping for Hanoi in 2019. First, we evaluated several traditional machine learning models, as a result, XGBoost classifier stands
out as the best model with 86% overall accuracy (OA). As Hanoi is a frequent cloud-covered area, the combination of optical data and radar data helps to improve the quality of the landcover map in 2019. The use of GEE has made it easier and faster through the provided JavaScript API when ensuring high accuracy.Ba Nam Buinambb@fimo.edu.vnAnh Phananhp@fimo.edu.vnThi Nhat Thanh Nguyenthanhntn@vnu.edu.vn2020-12-26T09:29:35Z2020-12-26T09:29:35Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/4330This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/43302020-12-26T09:29:35ZThe new design of cows' behavior classifier based on acceleration data and proposed feature setMonitor and classify behavioral activities in cows is a helpful support solution for livestock based on the analysis of data from sensors attached to the animal. Accelerometers are particularly suited for monitoring cow behaviors due to small size, lightweight and high accuracy. Nevertheless, the interpretation of the data collected by such sensors when characterizing the type of behaviors still brings major challenges to developers, related to activity complexity (i.e., certain behaviors contain similar gestures). This paper presents a new design of cows' behavior classifier based on acceleration data and proposed feature set. Analysis of cow acceleration data is used to extract features for classification using machine learning algorithms. We found that with 5 features (mean, standard deviation, root mean square, median, range) and 16-second window of data (1 sample/second), classification of seven cow behaviors (including feeding, lying, standing, lying down, standing up, normal walking, active walking) achieved the overall highest performance. We validated the results with acceleration data from a public source. Performance of our proposed classifier was evaluated and compared to existing ones in terms of the sensitivity, the accuracy, the positive predictive value, and the negative predictive value.Phung Cong Phi KhanhDuc-Tan TranVan Tu DuongNguyen Hong ThinhDuc-Nghia Tran2020-12-26T09:07:33Z2020-12-26T09:07:33Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/4328This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/43282020-12-26T09:07:33ZAdaptive Noise Filter for Real-Time Stress ECG Signal AnalysisThe stress Electrocardiogram (ECG) gives more efficient results for the diagnosis of cardiovascular diseases, which may not be apparent when the patients are at rest. However, the noise produced by the movement of the patient and the environment often contaminates the ECG signal. Motion artifact is the most prevalent and difficult type of interference to filter in stress test ECG. It corrupts the quality of the desired signal thus reducing the reliability of the stress test. In this work, we first describe a quantitative study of adaptive filtering for processing the stress ECG signals. The proposed method uses the motion information obtained from a 3-axis accelerometer as a noise reference signal for the adaptive filter and the optimal weight of the adaptive filter is adjusted by the Modified Error Data Normalized Step-Size (MEDNSS) algorithm. Finally, the performance of the proposed algorithm is tested on the stress ECG signal from the subject.Van Manh Hoangmanhhv87@vnu.edu.vnManh Thang Phamthangpm@vnu.edu.vn2020-12-26T09:05:53Z2020-12-26T09:05:53Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/4324This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/43242020-12-26T09:05:53ZHệ thống bốc số xếp hàng đồng bộ thời gian thực đa giao thức
Multi-protocol real-time synchronous queuing systemTheo thống kê mới nhất của Adsota Việt Nam, đầu năm 2020, gần 50% dân số Việt Nam đang dùng điện thoại thông minh (smartphone) với tổng số khoảng 43,7 triệu smartphone; Nhiều người cùng lúc sử dụng hơn 2 chiếc điện thoại với tỷ lệ sở hữu máy trung bình là 1,7 máy/người; Nhiều người Việt lên mạng bằng điện thoại nhiều hơn cả máy tính, con số cụ thể là 68%. Hiện nay, tại Việt Nam có 70% các thuê bao di động đang sử dụng internet từ 3G hoặc 4G với tốc độ trung bình là 14,6 Mbps [1].Nguyen Thuc Vuthucvn@vnu.edu.vnHoang Gia Nguyen2020-12-26T09:05:11Z2020-12-26T09:05:11Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/4323This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/43232020-12-26T09:05:11ZHệ thống bốc số xếp hàng đồng bộ thời gian thực đa giao thức
Multi-protocol real-time synchronous queuing systemTheo thống kê mới nhất của Adsota Việt Nam, đầu năm 2020, gần 50% dân số Việt Nam đang dùng điện thoại thông minh (smartphone) với tổng số khoảng 43,7 triệu smartphone; Nhiều người cùng lúc sử dụng hơn 2 chiếc điện thoại với tỷ lệ sở hữu máy trung bình là 1,7 máy/người; Nhiều người Việt lên mạng bằng điện thoại nhiều hơn cả máy tính, con số cụ thể là 68%. Hiện nay, tại Việt Nam có 70% các thuê bao di động đang sử dụng internet từ 3G hoặc 4G với tốc độ trung bình là 14,6 Mbps [1].Nguyen Thuc Vuthucvn@vnu.edu.vnHoang Gia Nguyen2020-12-25T11:15:15Z2020-12-25T11:15:15Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/4335This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/43352020-12-25T11:15:15ZOn the Gaussian Cramér-Rao Bound for Blind Single-Input
Multiple-Output System Identification: Fast and Asymptotic
ComputationsThe Cramér-Rao Bound (CRB) is a powerful tool to assess the performance limits of a parameter estimation problem for a given statistical model. In particular, the Gaussian CRB (i.e., the CRB obtained assuming the data are Gaussian) corresponds to the worst case; giving the largest CRB among a large class of data distributions. This makes it very useful in practice since optimizing under the Gaussian data assumption can be interpreted as a min-max optimization (i.e., minimizing the largest CRB). The Gaussian CRB is also the corresponding bound of Second-Order Statistics (SOS)-based estimation methods, which are frequently used in practice. Despite its practicality, computing this bound might be cumbersome in some cases, particularly in the case where the input is assumed deterministic and has a large number of samples. In this paper, we address this computational issue by proposing a fast computation for the deterministic Gaussian CRB of Single-Input Multiple Output (SIMO) blind system identification. More precisely, we exploit circulant matrix properties to reduce the cost from cubic to quadratic with respect to the sample size. Moreover, we derive a closed-form formula for the asymptotic (large sample size) Gaussian CRB and show how it can be computed using the residue theorem.Nait-Meziane MohamedAbed Meraim Karimkarim.abed-meraim@univ-orleans.frZhao ZhipengLinh Trung Nguyenlinhtrung@vnu.edu.vn2020-12-25T10:22:48Z2020-12-26T05:21:54Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/4333This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/43332020-12-25T10:22:48ZA Comprehensive Survey of Enabling and Emerging Technologies for Social Distancing——Part II: Emerging Technologies and Open IssuesThis two-part paper aims to provide a comprehensive survey on how emerging technologies, e.g., wireless and networking, artificial intelligence (AI) can enable, encourage, and even enforce social distancing practice. In Part I, an extensive background of social distancing is provided, and enabling wireless technologies are thoroughly surveyed. In this Part II, emerging technologies such as machine learning, computer vision, thermal, ultrasound, etc., are introduced. These technologies open many new solutions and directions to deal with problems in social distancing, e.g., symptom prediction, detection and monitoring quarantined people, and contact tracing. Finally, we discuss open issues and challenges (e.g., privacy-preserving, scheduling, and incentive mechanisms) in implementing social distancing in practice. As an example, instead of reacting with ad-hoc responses to COVID-19-like pandemics in the future, smart infrastructures (e.g., next-generation wireless systems like 6G, smart home/building, smart city, intelligent transportation systems) should incorporate a pandemic mode in their standard architectures/designs.Thanh Cong NguyenSaputra Yuris MulyaYurisMulya.Saputra@student.uts.edu.auVan Nguyen HuynhNgoc Tan Nguyennguyen.tan170@gmail.comViet Khoa Trankhoatv.uet@vnu.edu.vnTuan Bui Minhtuanbm.uet@vnu.edu.vnNguyen DiepDiep.Nguyen@uts.edu.auThai Hoang DinhHoang.Dinh@uts.edu.auXuan Thang Vuthang.vu85@gmail.comDutkiewicz Erykeryk.dutkiewicz@uts.edu.auChatzinotas SymeonOttersten Bjorn2020-12-25T10:12:57Z2020-12-25T10:12:57Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/4332This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/43322020-12-25T10:12:57ZA Comprehensive Survey of Enabling and Emerging Technologies for Social Distancing—Part I: Fundamentals and Enabling TechnologiesSocial distancing plays a pivotal role in preventing the spread of viral diseases illnesses such as COVID-19. By minimizing the close physical contact among people, we can reduce the chances of catching the virus and spreading it across the community. This two-part paper aims to provide a comprehensive survey on how emerging technologies, e.g., wireless and networking, artificial intelligence (AI) can enable, encourage, and even enforce social distancing practice. In this Part I, we provide a comprehensive background of social distancing including basic concepts, measurements, models, and propose various practical social distancing scenarios. We then discuss enabling wireless technologies which are especially effectin social distancing, e.g., symptom prediction, detection and monitoring quarantined people, and contact tracing. The companion paper Part II surveys other emerging and related technologies, such as machine learning, computer vision, thermal, ultrasound, etc., and discusses open issues and challenges (e.g., privacypreserving, scheduling, and incentive mechanisms) in implementing social distancing in practice.Thanh Cong NguyenSaputra Yuris MulyaYurisMulya.Saputra@student.uts.edu.auNgoc Tan Nguyennguyen.tan170@gmail.comViet Khoa Trankhoatv.uet@vnu.edu.vnMinh Tuan Buituanbm.uet@vnu.edu.vnNguyen DiepThai Hoang DinhXuan Thang Vuthang.vu85@gmail.comDutkiewicz Erykeryk.dutkiewicz@uts.edu.auChatzinotas SymeonOttersten Bjorn2020-12-23T14:22:37Z2020-12-23T14:22:37Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/4322This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/43222020-12-23T14:22:37ZAnalysis of CALIPSO satellite imagery for air pollution source identification in Hanoi, VietnamTuan Vinh TranVan Ha PhamThanh Thuy Nguyennguyenthanhthuy@vnu.edu.vnThi Nhat Thanh Nguyenthanhntn@vnu.edu.vn2020-12-23T14:20:27Z2020-12-23T14:20:27Zhttp://eprints.uet.vnu.edu.vn/eprints/id/eprint/4320This item is in the repository with the URL: http://eprints.uet.vnu.edu.vn/eprints/id/eprint/43202020-12-23T14:20:27ZParticulate Matter Concentration Mapping from Satellite ImageryThi Nhat Thanh Nguyenthanhntn@vnu.edu.vnViet Hung LuuVan Ha PhamQuang Hung Buihungbq@vnu.edu.vnThi Kim Oanh Nguyen