Journal of Science and Technique最新文献_第2页

DYNAMIC RESPONSE ANALYSIS OF h-FGS PLATES SUBJECTED TO CONSECUTIVE BLAST LOADING 受到连续冲击载荷的 h-FGS 平板的动态响应分析

Journal of Science and Technique Pub Date : 2024-07-08 DOI: 10.56651/lqdtu.jst.v7.n01.826.sce

Manh Tuan Duong

引用次数: 0

ASSESSMENT OF IMPERVIOUS SURFACE CHANGES FROM MULTI-TEMPORAL LANDSAT DATA AND MACHINE LEARNING TECHNIQUES. A CASE STUDY IN HO CHI MINH CITY 从多时空陆地卫星数据和机器学习技术评估不透水表面的变化。胡志明市案例研究

Journal of Science and Technique Pub Date : 2024-07-08 DOI: 10.56651/lqdtu.jst.v7.n01.827.sce

Van Phu Le

{"title":"ASSESSMENT OF IMPERVIOUS SURFACE CHANGES FROM MULTI-TEMPORAL LANDSAT DATA AND MACHINE LEARNING TECHNIQUES. A CASE STUDY IN HO CHI MINH CITY","authors":"Van Phu Le","doi":"10.56651/lqdtu.jst.v7.n01.827.sce","DOIUrl":"https://doi.org/10.56651/lqdtu.jst.v7.n01.827.sce","url":null,"abstract":"Impervious surface is an artificial surface that prevents water from seeping into the ground. Impervious surface is not only an indicator of the level of urbanization but also a key indicator of the quality of the urban environment. This article presents the results of an impervious surface classification in the Ho Chi Minh City area from multi-temporal Landsat image data. Three Landsat image scenes from 2010 - 2020, including Landsat 5 images taken on February 11, 2010, Landsat 8 images taken on February 9, 2015 and February 23, 2020 are used to classify land cover/land use, including impervious surface. Three machine learning algorithms (Random Forest, Support Vector Machine, Classification and Regression Tree) and maximum likelihood method are tested to select the algorithm with the highest accuracy. The results indicate that the Random Forest algorithm achieves the highest accuracy in classifying impervious surfaces, with an overall accuracy exceeding 93% and a Kappa coefficient of 0.915. The results received in the study also show an increase in impervious surface area in Ho Chi Minh City in the period 2010 - 2020. This is important information, helping managers in monitoring and planning urban areas.","PeriodicalId":476702,"journal":{"name":"Journal of Science and Technique","volume":"10 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141668087","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

IMPROVING THE LOCALIZATION IN THE DOCKING PROBLEM OF THE VIBOT-2 MOBILE ROBOT 改进 vibot-2 移动机器人对接问题中的定位功能

Journal of Science and Technique Pub Date : 2023-12-12 DOI: 10.56651/lqdtu.jst.v18.n03.644

Dinh-Quan Nguyen

{"title":"IMPROVING THE LOCALIZATION IN THE DOCKING PROBLEM OF THE VIBOT-2 MOBILE ROBOT","authors":"Dinh-Quan Nguyen","doi":"10.56651/lqdtu.jst.v18.n03.644","DOIUrl":"https://doi.org/10.56651/lqdtu.jst.v18.n03.644","url":null,"abstract":"This article presents a positioning solution for a mobile robot system, the Vibot-2 robot, in the docking problem where the robot must move backwards precisely to the charging position or the location to pick up the delivery cart (or return the cart) during the execution tasks. The localization system needs to calculate the robot's posture (including position coordinates and heading angle) in a fixed coordinate system attached to a fixed station with an accuracy within an allowable limit. The solution to build a positioning module for the Vibot-2 robot uses a stereo camera in combination with AprilTags mounted on a locator plate fixed at the station. Compared with the previous positioning solution applied to the Vibot-2 system, the proposed solution in this article changes the camera type and fiducial tag layout. Experimental results show that the new solution helps to increase the field of view of the positioning module by 30%, increase the measurement accuracy by more than 4 times in term of the average error in the horizontal axis, and at the same time, reduce the rate of measurements with errors outside the allowable limit in term of position by more than 1.5 times and in term of heading angle by more than 2 times.","PeriodicalId":476702,"journal":{"name":"Journal of Science and Technique","volume":"11 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139008697","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

INTEGRATING ANN AND CS TO IMPROVE TOOL WEAR PREDICTION IN HIGH-SPEED DRY TURNING OF SKD11 STEEL 整合 ann 和 cs 以改进 skd11 钢高速干车削过程中的刀具磨损预测

Journal of Science and Technique Pub Date : 2023-12-12 DOI: 10.56651/lqdtu.jst.v18.n03.722

Thi Dieu Hoang

引用次数: 0

MINOR HEAD LOSS ANALYSIS OF LAMINAR FLUID FLOW IN COMPLEX GEOMETRIES 复杂几何结构中层流流体流动的小水头损失分析

Journal of Science and Technique Pub Date : 2023-12-12 DOI: 10.56651/lqdtu.jst.v18.n03.728

Manh Hung Nguyen

{"title":"MINOR HEAD LOSS ANALYSIS OF LAMINAR FLUID FLOW IN COMPLEX GEOMETRIES","authors":"Manh Hung Nguyen","doi":"10.56651/lqdtu.jst.v18.n03.728","DOIUrl":"https://doi.org/10.56651/lqdtu.jst.v18.n03.728","url":null,"abstract":"Minor head loss occurs in most hydraulic equipment because the flow is affected by a shape change. Head loss analysis is essential in designing and fabricating hydraulic equipment and systems. In the general case, the evaluation of head losses is challenging and usually done by experimental methods. Recently, the calculation has been more convenient using the computational fluid dynamics (CFD) method. This article employs the finite element method (FEM) to evaluate the local hydraulic losses in complex geometries discretized by unstructured mesh. The method is applied to the laminar flow of Newtonian fluid. First, the code is validated by comparing the numerical solution with experimental data and previous numerical results. The code is then employed to simulate different problems, including a complex geometry that mimics the control valve in hydraulic systems. Simultaneously, the minor loss coefficient is calculated for different Re numbers. From the results, the minor loss coefficient is large for low Re, and can be up to 700 for Re = 10 of complicated geometry. For a high Re, the minor loss coefficient is rapidly decreased and close to the value of a turbulent model.","PeriodicalId":476702,"journal":{"name":"Journal of Science and Technique","volume":"34 8","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139007584","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

SIMULATION OF DISCRETE GUST ACCORDING TO AIRSHIP SAFETY STANDARDS 根据飞艇安全标准模拟离散阵风

Journal of Science and Technique Pub Date : 2023-12-12 DOI: 10.56651/lqdtu.jst.v18.n03.652

Xuan Tung Ta

引用次数: 0

NONLINEAR STABILITY CONTROL OF INVERTED PENDULUM ON A CART USING LQR-BASED T-S FUZZY CONTROL 利用基于 LQR 的 T-S 模糊控制实现小车上倒摆的非线性稳定控制

Journal of Science and Technique Pub Date : 2023-12-12 DOI: 10.56651/lqdtu.jst.v18.n03.693

Thi-Van-Anh Nguyen

引用次数: 0

RESEARCH ON AERODYNAMIC NOISE CHARACTERISTICS OF HELICOPTER ROTORS CONSIDERING THE INFLUENCE OF BLADE SHAPES 考虑叶片形状影响的直升机旋翼气动噪声特性研究

Journal of Science and Technique Pub Date : 2023-12-12 DOI: 10.56651/lqdtu.jst.v18.n03.613

Quang Quyen Le

引用次数: 0