SAIEE Africa Research Journal最新文献_第6页

Substrate Integrated Waveguide - Dielectric Resonator Antenna for Future Wireless Communication 用于未来无线通信的衬底集成波导-介质谐振天线

IF 1.4

SAIEE Africa Research Journal Pub Date : 2022-08-09 DOI: 10.23919/SAIEE.2022.9853021

Emmanuel K. Chemweno;Pradeep Kumar;Thomas J. O. Afullo

{"title":"Substrate Integrated Waveguide - Dielectric Resonator Antenna for Future Wireless Communication","authors":"Emmanuel K. Chemweno;Pradeep Kumar;Thomas J. O. Afullo","doi":"10.23919/SAIEE.2022.9853021","DOIUrl":"10.23919/SAIEE.2022.9853021","url":null,"abstract":"A substrate integrated waveguide (SIW) fed rectangular-shaped dielectric resonator antenna (DRA) is proposed for application in the D - Band frequency regime. The Dielectric Resonator (DR) is designed to operate in higher order modes. A rectangular-shaped narrow slot is used to excite the DR element, leading to multiple resonances. The resulting structure is a multi-resonant antenna operating at six frequencies at 123.64 GHz, 125.76 GHz, 127.4 GHz, 129.9 GHz, 134.9 GHz and 137.7 GHz frequencies. These are identified as TE10δ1, TE7δ5, TEδ31, TEδ25, TEδ31 and TEδ35 modes of operation of the resonator, respectively. These resonances are merged to achieve a −10 dB impedance bandwidth ranging between 122.58 GHz and 139.51 GHz, equivalent to 13.4% at a center frequency of 125.76 GHz. Moreover, the antenna possesses a stable radiation pattern in the broadband direction, across the entire frequency band of operation. Simulation results show that the antenna has a peak gain of 12.3 dBi, maximum directivity of 13.14 dBi and maximum efficiency of 84% at a frequency of 126 GHz. Simulated results show that the proposed design has potential and suitability for utilization in future wireless communications.","PeriodicalId":42493,"journal":{"name":"SAIEE Africa Research Journal","volume":"113 3","pages":"119-128"},"PeriodicalIF":1.4,"publicationDate":"2022-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/iel7/8475037/9853016/09853021.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46649222","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 7

Notes for authors 作者须知

IF 1.4

SAIEE Africa Research Journal Pub Date : 2022-08-09 DOI: 10.23919/SAIEE.2022.9853023

引用次数: 0

Editors and reviewers 编辑和评审

IF 1.4

SAIEE Africa Research Journal Pub Date : 2022-08-09 DOI: 10.23919/SAIEE.2022.9853018

引用次数: 0

A New Method to Distinguish between Nearby and Direct Lightning Strikes for Long Operational Medium Voltage Lines 长运行中压线路近雷击与直雷击判别新方法

IF 1.4

SAIEE Africa Research Journal Pub Date : 2022-08-09 DOI: 10.23919/SAIEE.2022.9853020

Willem J. Dirkse van Schalkwyk;Chandima Gomes;John M. van Coller

{"title":"A New Method to Distinguish between Nearby and Direct Lightning Strikes for Long Operational Medium Voltage Lines","authors":"Willem J. Dirkse van Schalkwyk;Chandima Gomes;John M. van Coller","doi":"10.23919/SAIEE.2022.9853020","DOIUrl":"10.23919/SAIEE.2022.9853020","url":null,"abstract":"Lightning strikes near Medium Voltage (MV) electricity distribution lines cause voltage transients to be induced onto the conductors of the power lines. The resultant Lightning Induced Overvoltage (LIOV) on the phase conductors may be estimated using computer models or measurements. Models and measurements are mostly limited to short floating lines to simplify calculations and to ensure accurate results that can be easily compared between different models. Existing measurement methods cannot be used to distinguish between nearby lightning and direct lightning strikes to an operational MV network by using only one instrument on a line that is more than 100 km long. The instrument needs to be less than a hundred meters from where the LIOV amplitude on the line is the highest. The new method described in this paper allows one to distinguish between nearby and direct lightning strikes to the line; by comparing the polarity of the current transient recorded at the substation to the lightning return-stroke polarity obtained from a lightning detection network. The new method also allows one to determine whether the LIOV of a particular lightning transient exceeded the Basic Insulation Level (BIL) of the line, by observing the power frequency fault current. The new method was applied to an operational 714 km network operating at 22 kV, and the results were compared with predictions in IEEE Std 1410-2010. Significantly fewer line faults due to nearby lightning were observed than predicted; the reason for this is explained.","PeriodicalId":42493,"journal":{"name":"SAIEE Africa Research Journal","volume":"113 3","pages":"108-118"},"PeriodicalIF":1.4,"publicationDate":"2022-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/iel7/8475037/9853016/09853020.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42114931","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Research on Payment Settlement Mode in Cross-Border Business Trade Based on Blockchain Technology 基于区块链技术的跨境贸易支付结算模式研究

IF 1.4

SAIEE Africa Research Journal Pub Date : 2022-08-09 DOI: 10.23919/SAIEE.2022.9853022

Xiaoyan Wang

引用次数: 0

Notes for authors 作者须知

IF 1.4

SAIEE Africa Research Journal Pub Date : 2022-03-30 DOI: 10.23919/SAIEE.2022.9785544

引用次数: 0

Low Complexity Deep Learning-Assisted Golden Code Sphere-Decoding with Sorted Detection Subsets 基于检测子集排序的低复杂度深度学习辅助金码球解码

IF 1.4

SAIEE Africa Research Journal Pub Date : 2022-03-30 DOI: 10.23919/SAIEE.2022.9785542

Bhekisizwe Mthethwa;Hongjun Xu

{"title":"Low Complexity Deep Learning-Assisted Golden Code Sphere-Decoding with Sorted Detection Subsets","authors":"Bhekisizwe Mthethwa;Hongjun Xu","doi":"10.23919/SAIEE.2022.9785542","DOIUrl":"10.23919/SAIEE.2022.9785542","url":null,"abstract":"Golden code is a space-time block coding (STBC) scheme that has spatial multiplexing gain over the Alamouti STBC which is widely used in modern wireless communication standards. Golden code has not been widely adopted in modern wireless standards because of its inherent high detection complexity. However, detection algorithms like the sphere-decoding with sorted detection subsets (SD-SDS) have been developed to lower this detection complexity. Literature indicates that the SD-SDS algorithm has lower detection complexity relative to the traditional sphere-decoding (SD) algorithm, for all signal-to-noise ratio (SNR) values. The SD-SDS algorithm exhibits low detection complexity at high SNR; however, at low SNR the detection complexity is higher. We propose a deep neural network (DNN) aided SD-SDS algorithm (SD-SDS-DNN) that will lower the Golden code's SD-SDS low SNR detection complexity, whilst maintaining the bit-error-rate (BER) performance. The proposed SD-SDS-DNN is shown to achieve a 75% reduction in detection complexity relative to SD-SDS at low SNR values for 16-QAM, whilst maintaining the BER performance. For 64-QAM, the SD-SDS-DNN achieves 99% reduction in detection complexity relative to the SD-SDS at low SNR, whilst maintaining the BER performance. The SD-SDS-DNN has also shown to achieve low detection complexity comparable to that of the Alamouti linear maximum likelihood (ML) detector for a spectral efficiency of 8 bits/s/Hz. For a spectral efficiency of 12 bits/s/Hz, the SD-SDS-DNN achieves a detection complexity that is 90% lower than the Alamouti linear ML detector.","PeriodicalId":42493,"journal":{"name":"SAIEE Africa Research Journal","volume":"113 2","pages":"88-101"},"PeriodicalIF":1.4,"publicationDate":"2022-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/iel7/8475037/9785536/09785542.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47953830","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Applied Quasi-Distributed Fibre Bragg Grating Strain Sensors in Structural Damage Sensing of a Bridge Structure 准分布式光纤光栅应变传感器在桥梁结构损伤检测中的应用

IF 1.4

SAIEE Africa Research Journal Pub Date : 2022-03-30 DOI: 10.23919/SAIEE.2022.9785541

P. Banda;M. Della Tamin;J. Meyer

{"title":"Applied Quasi-Distributed Fibre Bragg Grating Strain Sensors in Structural Damage Sensing of a Bridge Structure","authors":"P. Banda;M. Della Tamin;J. Meyer","doi":"10.23919/SAIEE.2022.9785541","DOIUrl":"10.23919/SAIEE.2022.9785541","url":null,"abstract":"Bridge structural decay is a prevalent problem around the world. Consequently, most structurally deficient bridges are characterized by unknown levels of damage, which impose high socio-economic risks to society. To address these concerns, this study is aimed at determining how to accurately sense the damage present in a bridge structure. Owing to the pitfalls of conventional sensing technologies and the complexities associated with civil structure instrumentation, the use of fibre optics sensors is found to be relevant for this study. While the employment of quasi distributed fibre Bragg grating strain sensors is not a relatively new concept, research is still necessary for their effective deployment in structural damage monitoring systems. A proof of concept for the developed sensing system is primarily simulated and thereafter demonstrated in the laboratory through a series of strain measurements tests conducted on a reinforced concrete slab. The experimental set-up consisted of a serial array of five wavelength division multiplexed fibre Bragg grating sensors, which were coupled with swept wavelength laser scanning technology. The experimental sensing resolution of less than 0.5 με was achieved. Structural damage information was extracted from the measured multipoint flexural strains, using our developed macro-modal strain ratio cross correlation algorithm. Alternatively, to simulate our sensor system response, vibration field tests, and finite element analysis were conducted on the Beatrice Bridge in Zimbabwe. Therefore, this paper presents the simulation and experimental results of a simulated and designed structural damage sensing system, based on quasi-distributed fibre Bragg grating strain sensors.","PeriodicalId":42493,"journal":{"name":"SAIEE Africa Research Journal","volume":"113 2","pages":"75-87"},"PeriodicalIF":1.4,"publicationDate":"2022-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/iel7/8475037/9785536/09785541.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46521837","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Measurement-based load parameter modelling for technical and tariff studies of medium voltage feeders 中压馈线技术和电价研究中基于测量的负荷参数建模

IF 1.4

SAIEE Africa Research Journal Pub Date : 2022-03-30 DOI: 10.23919/SAIEE.2022.9785540

Johannes L. Buys;Charles T. Gaunt

{"title":"Measurement-based load parameter modelling for technical and tariff studies of medium voltage feeders","authors":"Johannes L. Buys;Charles T. Gaunt","doi":"10.23919/SAIEE.2022.9785540","DOIUrl":"10.23919/SAIEE.2022.9785540","url":null,"abstract":"Transformation in the South African power sector and new load patterns necessitated a review of load models used for financial, technical and tariff analysis. This pilot study took advantage of available data of customer measurements on medium Voltage (MV) feeders in Eskom's database. Load models with distinct profiles for typical days were developed for non-overlapping customer classes using a set of coherent parameters derived from MV chronological load profiles and the k-means algorithm. The results suggested that two profiles can be used to for summer and two profiles can be used for winter instead of using 365 hourly profiles for simulations. The results also reveal that load classification can be improved when the parameters are directed towards specific objectives, and also when the k-means algorithm is supervised using exogenous (external) parameters of loads. A comparison of the results to the economic activity class suggests that there are sub-clusters identifiable within the economic classes. The proposed process is practical, implementable with available data and suitable for various studies on MV networks.","PeriodicalId":42493,"journal":{"name":"SAIEE Africa Research Journal","volume":"113 2","pages":"64-74"},"PeriodicalIF":1.4,"publicationDate":"2022-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/iel7/8475037/9785536/09785540.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48743960","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Editors and reviewers 编辑和评审

IF 1.4

SAIEE Africa Research Journal Pub Date : 2022-03-30 DOI: 10.23919/SAIEE.2022.9785538

引用次数: 0