发布求助
文献互助 智能选刊 最新文献

Journal of Science and Technology Issue on Information and Communications Technology最新文献

筛选
英文 中文
Wideband MIMO Antenna for 5G Base Station 5G基站宽带MIMO天线
Journal of Science and Technology Issue on Information and Communications Technology Pub Date : 2023-06-30 DOI: 10.31130/ud-jst.2023.105
Hien Huynh Thi Ngoc
{"title":"Wideband MIMO Antenna for 5G Base Station","authors":"Hien Huynh Thi Ngoc","doi":"10.31130/ud-jst.2023.105","DOIUrl":"https://doi.org/10.31130/ud-jst.2023.105","url":null,"abstract":"In this paper, we present a configuration of a wideband MIMO antenna array for 5G terminals. The single-element antenna has compact size, dual polarization, wide operating bandwidth covering the 5G N78 frequency band, and high isolation between the two input ports (>40 dB). The 4×1 radiation sub-array has dual polarization, low mutuality and high spatial diversity characteristics over the entire operating frequency range. The large-scale MIMO antenna array with a single 4×8 configuration can provide 8 independent beams azimuth sweep and 8 independent beams sweep azimuth. When exciting all ports in either horizontal or vertical bias, a large-scale MIMO antenna array can produce a main beam with a maximum realized gain of about 22 dBi. With many advantages of low profile, wideband, low mutuality, this large-scale MIMO antenna array can be applied to the current generation of 5G mobile base stations.","PeriodicalId":262140,"journal":{"name":"Journal of Science and Technology Issue on Information and Communications Technology","volume":"108 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130278347","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
A Review of Achieving Frequency Reconfiguration for Antennas in Wireless Communications 无线通信中天线频率重构的实现综述
Journal of Science and Technology Issue on Information and Communications Technology Pub Date : 2023-06-30 DOI: 10.31130/ud-jst.2023.090ict
Hoang Thi Phuong Thao
{"title":"A Review of Achieving Frequency Reconfiguration for Antennas in Wireless Communications","authors":"Hoang Thi Phuong Thao","doi":"10.31130/ud-jst.2023.090ict","DOIUrl":"https://doi.org/10.31130/ud-jst.2023.090ict","url":null,"abstract":"Reconfigurable antennas are a type of smart antenna that is able to change whose properties, including resonant frequency, polarization, radiation pattern, and a combination of these properties. Reconfigurable antennas can switch between their configuration states to operate at different frequency bands for multiple standards, change their radiation patterns for direction finding, or change their polarization for polarization diversity. Therefore, they are a solution for modern wireless communications to meet the requirements of the system’s multi-functionality. This paper presents different reconfigurable antennas with various techniques to obtain antenna reconfiguration. The reconfigurable antenna can be achieved using electrical components (PIN diodes, RFMEMSs, varactors, FETs), optical diodes, smart materials (liquid crystal or ferrites), or physical alteration of antenna structures. The comparison and summarization of different reconfiguration techniques are described in the paper. The publications on reconfigurable antennas are mentioned and illustrated with discussions.","PeriodicalId":262140,"journal":{"name":"Journal of Science and Technology Issue on Information and Communications Technology","volume":"267 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121154722","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
Assessment of Methods to Limit The Impact of Hot Spot Phenomenon on Photovoltaic Power 限制热点现象对光伏发电影响的方法评估
Journal of Science and Technology Issue on Information and Communications Technology Pub Date : 2023-06-30 DOI: 10.31130/ud-jst.2023.064
Trung Hieu Trinh, D. Nguyen, Thi-Thanh-Quynh Nguyen, Dinh T. Ha
{"title":"Assessment of Methods to Limit The Impact of Hot Spot Phenomenon on Photovoltaic Power","authors":"Trung Hieu Trinh, D. Nguyen, Thi-Thanh-Quynh Nguyen, Dinh T. Ha","doi":"10.31130/ud-jst.2023.064","DOIUrl":"https://doi.org/10.31130/ud-jst.2023.064","url":null,"abstract":"Most solar systems consist of small power, low voltage panels connected in series or parallel to increase voltage and power. However, connecting the panels in series can lead to certain operational limitations. In the case where the panels are partially shaded by clouds, trees, or damaged elements, the current flowing through the solar system is reduced to the level of weakest panel in the string. The paper introduces the distributed maximum power point tracking (DMPPT) model to obtain the maximum power of the solar system when working in shaded conditions. PSIM software is used to evaluate the performance of the DMPPT model for a solar system consisting of 4 TP250MBZ panels. The simulation results show that when the shading occurs, the use of the DMPPT model will obtain a higher power than the central maximum power point tracking model (CMPPT).","PeriodicalId":262140,"journal":{"name":"Journal of Science and Technology Issue on Information and Communications Technology","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129326824","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
A combination of forensic-based investigation algorithm and density peak-based fuzzy clustering for custom segmentation 基于取证的调查算法和基于密度峰的模糊聚类相结合的自定义分割
Journal of Science and Technology Issue on Information and Communications Technology Pub Date : 2023-06-30 DOI: 10.31130/ud-jst.2023.081e
T. Nguyen
{"title":"A combination of forensic-based investigation algorithm and density peak-based fuzzy clustering for custom segmentation","authors":"T. Nguyen","doi":"10.31130/ud-jst.2023.081e","DOIUrl":"https://doi.org/10.31130/ud-jst.2023.081e","url":null,"abstract":"Custom segmentation is a process of classifying potential customers based on their mutual features such as shopping habits, consumption trends, and demand to provide an effective marketing campaign for each customer group. Data clustering is one of the most common methods for custom segmentation. This study proposed a novel clustering method that employs density peak-based fuzzy c-means (DP-FCM) and forensic-based investigation (FBI) algorithms. The proposed method (denoted as DP-FBI-FCM) aims to provide an effective clustering technique that can exploit the global optimal solution for custom segmentation problems. Besides, the proposed DP-FBI-FCM is used to segment wholesale customer data of a supermarket. As a result, four distinct customer groups are classified. Businesses can implement different strategies in each cluster to retain and attract their customers.","PeriodicalId":262140,"journal":{"name":"Journal of Science and Technology Issue on Information and Communications Technology","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126738122","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
Internal force analysis of beams on elastic foundation using differential evolutionary optimization algorithm based on hybrid mutation technique 基于混合突变技术的弹性地基梁内力分析
Journal of Science and Technology Issue on Information and Communications Technology Pub Date : 2023-06-30 DOI: 10.31130/ud-jst.2023.180e
Lê Cong Duy, Nguyen Quang Hoa, Nguyen Thi Van Loan
{"title":"Internal force analysis of beams on elastic foundation using differential evolutionary optimization algorithm based on hybrid mutation technique","authors":"Lê Cong Duy, Nguyen Quang Hoa, Nguyen Thi Van Loan","doi":"10.31130/ud-jst.2023.180e","DOIUrl":"https://doi.org/10.31130/ud-jst.2023.180e","url":null,"abstract":"The paper presents the Finite element method (FEM) that calculates the internal force and the displacement of beams on elastic foundation in the case of the uncertainty input parameters described in terms of the number intervals. Using the interval function optimization algorithm combined with the FEM to determine the internal force values of the span reinforced concrete beam structure. This study applies the hybrid differential evolutionary optimization algorithm combined with FEM interval functions to determine the required internal force results of reinforced concrete beams placed on an elastic foundation. The calculation process is programmed using Maple.17 software to determine the displacement output and the resulting internal force in the beam. To check the correctness of the program calculated on Maple.17, the input declared dataset corresponds to the central values of the interval numbers and is recalculated by SAP2000v21 software, then evaluates the results error of internal force on the beam under consideration.","PeriodicalId":262140,"journal":{"name":"Journal of Science and Technology Issue on Information and Communications Technology","volume":"94 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134466363","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
In-vitro antibacterial activity of the fractions from Cleistocalyx operculatus (Roxb.) Merr. et Perry against Staphylococcus aureus 闭锁花提取物的体外抗菌活性研究稳定。让佩里对抗金黄色葡萄球菌
Journal of Science and Technology Issue on Information and Communications Technology Pub Date : 2023-06-30 DOI: 10.31130/ud-jst.2023.056e
Van Ngo Thai Bich, Thao Dao Thi Thu, Thanh Hoa Tran, Phu Tran Vinh Phu
{"title":"In-vitro antibacterial activity of the fractions from Cleistocalyx operculatus (Roxb.) Merr. et Perry against Staphylococcus aureus","authors":"Van Ngo Thai Bich, Thao Dao Thi Thu, Thanh Hoa Tran, Phu Tran Vinh Phu","doi":"10.31130/ud-jst.2023.056e","DOIUrl":"https://doi.org/10.31130/ud-jst.2023.056e","url":null,"abstract":"The prevalence of Gram-positive Staphylococcus aureus in infectious diseases is increasing in Vietnam for recent years. Therefore, novel class of antibiotic or active compounds is indispensable to treat this common worldwide pathogen. In the present study, we investigated the antibacterial activities of Cleistocalyx operculatus (Roxb.) Merr. et Perry leaves collected in Quang Nam. The results showed that ethanolic crude extract and three fractions partitioned in different polar solvents suppressed Staphylococcus aureus ATCC 6538. The ethyl acetate and n-hexan fractions exhibited a significant inhibitory effect, with minimum inhibitory concentrations (MIC) values of 0.1 mg/ml and 0.2 mg/ml, respectively. And flavonoids was possibly the active substances responsible for the antimicrobial activity of this medical plant. These initial findings are the premise of further studies for the treatment of infection. It also provides the scientific evidences for the traditional utilization of Cleistocalyx operculatus (Roxb.) Merr. et Perry leaves.","PeriodicalId":262140,"journal":{"name":"Journal of Science and Technology Issue on Information and Communications Technology","volume":"80 1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128980642","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
Computation Initial Degree and Waldschmidt Constant for Sets of Small Number of Multiple Points 少量多点集的初始度和Waldschmidt常数的计算
Journal of Science and Technology Issue on Information and Communications Technology Pub Date : 2023-06-30 DOI: 10.31130/ud-jst.2023.098ict
Nguyen Chanh Tu
{"title":"Computation Initial Degree and Waldschmidt Constant for Sets of Small Number of Multiple Points","authors":"Nguyen Chanh Tu","doi":"10.31130/ud-jst.2023.098ict","DOIUrl":"https://doi.org/10.31130/ud-jst.2023.098ict","url":null,"abstract":"Waldschmidt constant is firstly introduced by Waldschmidt in 1975. Since then, many results of this constant was achieved mostly about finding lower bounds. That is recently one of active, fascinating and important topics. However, computation of Waldschmidt constant or the initial degree is very hard in general, even for cases of small numbers of points  in the projective plane. Recently, the constants were computed for certain sets of points with one, two and three supporting lines. The paper shows values of the initial degree and Waldschmidt constant for sets with at most 6 points in all configurations in projective plane. These constants represent the complexity of optimal solutions in repeated path problems that have many applications in computer science, informatics theory and telecommunications.","PeriodicalId":262140,"journal":{"name":"Journal of Science and Technology Issue on Information and Communications Technology","volume":"85 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131389664","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: 1
The impact of policy uncertainty on stock liquidity in Vietnam’s M&A market 政策不确定性对越南并购市场股票流动性的影响
Journal of Science and Technology Issue on Information and Communications Technology Pub Date : 2023-06-30 DOI: 10.31130/ud-jst.2023.117e
Dang Huu Man, Nguyen Manh Toan
{"title":"The impact of policy uncertainty on stock liquidity in Vietnam’s M&A market","authors":"Dang Huu Man, Nguyen Manh Toan","doi":"10.31130/ud-jst.2023.117e","DOIUrl":"https://doi.org/10.31130/ud-jst.2023.117e","url":null,"abstract":"This study investigates the impact of policy uncertainty on stock liquidity in Vietnam’s M&A market. Using a comprehensive sample of M&A acquisition deals over the 2005-2020 period, we find that policy uncertainty is negatively associated with stock liquidity of target firms, indicating that firms should increase their information disclosure to improve the information environment during periods of increased asymmetric information due to policy uncertainty. We also find that higher levels of policy uncertainty lead to lower market valuations of target firms, reflecting greater market skepticism about the completion of the transaction and related synergy benefits. This study highlights the importance of transparency in improving stock liquidity and suggests that policymakers need to consider the impact of domestic economic and investment policies on M&A activity and stock liquidity in Vietnam.","PeriodicalId":262140,"journal":{"name":"Journal of Science and Technology Issue on Information and Communications Technology","volume":"84 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115770824","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 Electric Truck Brake System Operating in Industrial Plants 电动卡车制动系统在工业厂房中的运行仿真
Journal of Science and Technology Issue on Information and Communications Technology Pub Date : 2023-06-30 DOI: 10.31130/ud-jst.2023.482ict
M. Le, Dinh Nghia Duong, Cong Tin Le
{"title":"Simulation of Electric Truck Brake System Operating in Industrial Plants","authors":"M. Le, Dinh Nghia Duong, Cong Tin Le","doi":"10.31130/ud-jst.2023.482ict","DOIUrl":"https://doi.org/10.31130/ud-jst.2023.482ict","url":null,"abstract":"This study analyzes the quarter car braking model to determine the effect of the wheel slip ratio (λ) on  the friction coefficient (µ) during the braking of the car. The friction coefficient reaches a minimum when the slip ratio λ ∼ 1; maximum friction coefficient at the optimal slip ratio value from 0.18 to 0.2. Dynamic Model of the vehicle in the ABS brake study should consider in detail the dynamic aspects of braking and the interaction between the tire and the road profile. CarSim software is used in this study to simulate the braking system of a vehicle operating in industrial plant; Simulation is performed on both cases of ABS and non-ABS braking systems. The results of braking distance, deceleration, and brake pressure are considered and analyzed to select a suitable braking system for the operating conditions of the designed truck.","PeriodicalId":262140,"journal":{"name":"Journal of Science and Technology Issue on Information and Communications Technology","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133236318","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
Estimating Traffic Density in Uncertain Environment: A Case Study of Danang, Vietnam 不确定环境下的交通密度估算:以越南岘港为例
Journal of Science and Technology Issue on Information and Communications Technology Pub Date : 2023-06-30 DOI: 10.31130/ud-jst.2023.045e
Do Mien, Tran The Vu, Ngo Van Si
{"title":"Estimating Traffic Density in Uncertain Environment: A Case Study of Danang, Vietnam","authors":"Do Mien, Tran The Vu, Ngo Van Si","doi":"10.31130/ud-jst.2023.045e","DOIUrl":"https://doi.org/10.31130/ud-jst.2023.045e","url":null,"abstract":"The road traffic monitoring system in Vietnam faces significant challenges due to the impact of uncertain factors. The problems of blurred lanes, many types of vehicles in traffic, the view from remote surveillance cameras, etc, directly affect the intelligent traffic management system. We propose an algorithm to estimate the traffic density in an uncertain environment to identify and solve the above problems. Through empirical evaluation of the data set from cameras collected on the website http://0511.vn, it has been proved that this proposed method has high performance in real-time and has an equivalent accuracy to other high-complexity methods.","PeriodicalId":262140,"journal":{"name":"Journal of Science and Technology Issue on Information and Communications Technology","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115406660","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
首页 上一页 下一页 尾页
0
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
提示
您的信息不完整，为了账户安全，请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
现在去查看 取消
×
提示
确定
请完成安全验证×
相关产品
×
本文献相关产品
联系我们：info@booksci.cn Book学术提供免费学术资源搜索服务，方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。 Copyright © 2023 布克学术 All rights reserved.
京ICP备2023020795号-1
ghs 京公网安备 11010802042870号
Book学术文献互助
Book学术文献互助群
群 号：604180095
Book学术官方微信