Pub Date : 2023-11-15DOI: 10.23919/SAIEE.2023.10319382
{"title":"Notes for authors","authors":"","doi":"10.23919/SAIEE.2023.10319382","DOIUrl":"https://doi.org/10.23919/SAIEE.2023.10319382","url":null,"abstract":"","PeriodicalId":42493,"journal":{"name":"SAIEE Africa Research Journal","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10319382","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138138388","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}
Pub Date : 2023-11-15DOI: 10.23919/SAIEE.2023.10319376
{"title":"Editors and reviewers","authors":"","doi":"10.23919/SAIEE.2023.10319376","DOIUrl":"https://doi.org/10.23919/SAIEE.2023.10319376","url":null,"abstract":"","PeriodicalId":42493,"journal":{"name":"SAIEE Africa Research Journal","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10319376","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138138382","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}
Pub Date : 2023-11-15DOI: 10.23919/SAIEE.2023.10319378
Asmaa Hilmi;Soufiane Mezroui;Ahmed El Oualkadi
The chaotic map including 2D-Henon and Tent maps, have been widely used in modern cryptography, due to its high level of security and low cost of computation, compared to traditional algorithms. This study suggests a method for sharing images that are dependent on both confusion and diffusion for securing a gray-scale image. First, a new perturbation method of pixels based on Henon map to generate the permutation matrix for scrambling the plain image is proposed. The confused image should be encrypted, in which we combine the Frobenius endomorphism and Tent chaotic map to generate a key encryption. Using the eXclusive-OR operation, the substitution process is realized between the key encryption and confused image. The simulation results of the proposed scheme maintain a lossless encryption quality, and the security analysis, which includes differential attack entropy, correlation coefficient, and histogram analysis illustrate that the proposed approach reveals a high performance.
{"title":"An image encryption based on confusion-diffusion using two chaotic maps and Frobenius endomorphism","authors":"Asmaa Hilmi;Soufiane Mezroui;Ahmed El Oualkadi","doi":"10.23919/SAIEE.2023.10319378","DOIUrl":"https://doi.org/10.23919/SAIEE.2023.10319378","url":null,"abstract":"The chaotic map including 2D-Henon and Tent maps, have been widely used in modern cryptography, due to its high level of security and low cost of computation, compared to traditional algorithms. This study suggests a method for sharing images that are dependent on both confusion and diffusion for securing a gray-scale image. First, a new perturbation method of pixels based on Henon map to generate the permutation matrix for scrambling the plain image is proposed. The confused image should be encrypted, in which we combine the Frobenius endomorphism and Tent chaotic map to generate a key encryption. Using the eXclusive-OR operation, the substitution process is realized between the key encryption and confused image. The simulation results of the proposed scheme maintain a lossless encryption quality, and the security analysis, which includes differential attack entropy, correlation coefficient, and histogram analysis illustrate that the proposed approach reveals a high performance.","PeriodicalId":42493,"journal":{"name":"SAIEE Africa Research Journal","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10319378","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138138384","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}
Pub Date : 2023-11-15DOI: 10.23919/SAIEE.2023.10319380
Adedotun T. Ajibare;Sunday O. Oladejo;Stephen O. Ekwe;Lateef A. Akinyemi;Daniel Ramotsoela
In this study, the specific absorption rate (SAR) and exposure index (EI) of access points (APs) and user equipment (UEs) in fourth-generation (4G) and fifth-generation (5G) wireless technologies are examined with regard to the effects of exposure to radiofrequency (RF) electromagnetic fields (EMF) radiation and the implications of their reduction. We characterize the EI using a classical mathematical method while considering the power density, the SAR, the electric field strength, and the tissue's density and conductivity. As such, a novel exposure-index open-loop power control algorithm is proposed to evaluate the realistic RF-EMF radiation exposure on human users from both the downlink (DL) and uplink (UL) communication devices. To solve an EI minimization problem using the open-loop power control algorithm, we formulate it in the form of a mixed-integer nonlinear programming (MINLP) problem. As the energy capacity (i.e., power density) in wireless networks determines the radiation exposure (SAR and EI), it minimizes the EI by controlling and managing the transmitted and received powers under the restrictions of Quality of Service (QoS), interference, and power, while ensuring the users' QoS requirements are met. Our proposed scheme is numerically compared to other heuristic algorithms and exposure limits established by the International Commission on Non-Ionizing Radiation Protection (ICNIRP) and other similar organizations. Lastly, we compare the emissions from 4G and 5G networks to the emissions from UL and DL transmissions. Our simulation findings indicate that our proposed technique is a good alternative. Our assessment, in terms of numerical results and evaluation, also verifies that the exposures are bearable, fall within the recommended limits, and are minimized without impairing the users' QoS.
{"title":"Radiofrequency electromagnetic radiation exposure assessment, analysis, computation, and minimization technique in 5G networks: A perspective on QoS trade-offs","authors":"Adedotun T. Ajibare;Sunday O. Oladejo;Stephen O. Ekwe;Lateef A. Akinyemi;Daniel Ramotsoela","doi":"10.23919/SAIEE.2023.10319380","DOIUrl":"https://doi.org/10.23919/SAIEE.2023.10319380","url":null,"abstract":"In this study, the specific absorption rate (SAR) and exposure index (EI) of access points (APs) and user equipment (UEs) in fourth-generation (4G) and fifth-generation (5G) wireless technologies are examined with regard to the effects of exposure to radiofrequency (RF) electromagnetic fields (EMF) radiation and the implications of their reduction. We characterize the EI using a classical mathematical method while considering the power density, the SAR, the electric field strength, and the tissue's density and conductivity. As such, a novel exposure-index open-loop power control algorithm is proposed to evaluate the realistic RF-EMF radiation exposure on human users from both the downlink (DL) and uplink (UL) communication devices. To solve an EI minimization problem using the open-loop power control algorithm, we formulate it in the form of a mixed-integer nonlinear programming (MINLP) problem. As the energy capacity (i.e., power density) in wireless networks determines the radiation exposure (SAR and EI), it minimizes the EI by controlling and managing the transmitted and received powers under the restrictions of Quality of Service (QoS), interference, and power, while ensuring the users' QoS requirements are met. Our proposed scheme is numerically compared to other heuristic algorithms and exposure limits established by the International Commission on Non-Ionizing Radiation Protection (ICNIRP) and other similar organizations. Lastly, we compare the emissions from 4G and 5G networks to the emissions from UL and DL transmissions. Our simulation findings indicate that our proposed technique is a good alternative. Our assessment, in terms of numerical results and evaluation, also verifies that the exposures are bearable, fall within the recommended limits, and are minimized without impairing the users' QoS.","PeriodicalId":42493,"journal":{"name":"SAIEE Africa Research Journal","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10319380","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138138386","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}
Pub Date : 2023-11-15DOI: 10.23919/SAIEE.2023.10319379
Paula Akossiwa Atchike;Jamal Zbitou;Ahmed El Oualkadi;Pascal Dherbécourt
Electronic devices with high performances like Power Amplifiers (PA) are very important for Wireless communications. This paper proposes a design of a class AB power amplifier operating at 2.45 GHz, in the S-band frequency. The Cree's CG2H40045F GaN HEMT (High Electron Mobility Transistor) is used for this design. The Gallium Nitride (GaN) technology has been chosen in light of its advantageous properties such as high breakdown voltage, high band gap, as well as high thermal conditions. The paper investigates the different design trade-offs for finding a good balance between various key parameters of the PA (linearity, efficiency, and gain). A design approach has been proposed and the microstrip lines based on the Smith Chart tool available in ADS software have been used for the matching process. The class AB was selected to reach a good agreement between linearity and efficiency, provided by this class. After various process applications from DC characterization to simulations, the proposed design achieves a power added efficiency more than 50% at power saturation with a gain of 15 dB in schematic simulation. The layout dimensions are 55.5 × 64.45 mm 2 on PCB technology.
功率放大器(PA)等高性能电子器件对无线通信非常重要。本文提出了一种工作频率为2.45 GHz的s波段AB类功率放大器的设计方案。该设计使用Cree的CG2H40045F GaN HEMT(高电子迁移率晶体管)。氮化镓(GaN)技术具有高击穿电压、高带隙和高热条件等优点。本文研究了不同的设计权衡，以找到PA的各种关键参数(线性度，效率和增益)之间的良好平衡。提出了一种设计方法，并利用ADS软件中的史密斯图工具绘制微带线进行匹配。选择AB级是为了在线性度和效率之间达到很好的一致性，这是AB级提供的。经过从直流表征到仿真的各种工艺应用，所提出的设计在功率饱和时的功率增加效率超过50%，原理图仿真的增益为15 dB。PCB工艺上的布局尺寸为55.5 × 64.45 mm2。
{"title":"GaN HEMT power amplifier design for 2.45 GHz wireless applications","authors":"Paula Akossiwa Atchike;Jamal Zbitou;Ahmed El Oualkadi;Pascal Dherbécourt","doi":"10.23919/SAIEE.2023.10319379","DOIUrl":"https://doi.org/10.23919/SAIEE.2023.10319379","url":null,"abstract":"Electronic devices with high performances like Power Amplifiers (PA) are very important for Wireless communications. This paper proposes a design of a class AB power amplifier operating at 2.45 GHz, in the S-band frequency. The Cree's CG2H40045F GaN HEMT (High Electron Mobility Transistor) is used for this design. The Gallium Nitride (GaN) technology has been chosen in light of its advantageous properties such as high breakdown voltage, high band gap, as well as high thermal conditions. The paper investigates the different design trade-offs for finding a good balance between various key parameters of the PA (linearity, efficiency, and gain). A design approach has been proposed and the microstrip lines based on the Smith Chart tool available in ADS software have been used for the matching process. The class AB was selected to reach a good agreement between linearity and efficiency, provided by this class. After various process applications from DC characterization to simulations, the proposed design achieves a power added efficiency more than 50% at power saturation with a gain of 15 dB in schematic simulation. The layout dimensions are 55.5 × 64.45 mm\u0000<sup>2</sup>\u0000 on PCB technology.","PeriodicalId":42493,"journal":{"name":"SAIEE Africa Research Journal","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10319379","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138138385","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}
Pub Date : 2023-08-09DOI: 10.23919/SAIEE.2023.10214184
{"title":"Editors and reviewers","authors":"","doi":"10.23919/SAIEE.2023.10214184","DOIUrl":"https://doi.org/10.23919/SAIEE.2023.10214184","url":null,"abstract":"","PeriodicalId":42493,"journal":{"name":"SAIEE Africa Research Journal","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/iel7/8475037/10214182/10214184.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67845945","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}
Pub Date : 2023-08-09DOI: 10.23919/SAIEE.2023.10214186
Casey J. Bryant;P. Gideon Wiid
This article describes an antenna characterization measurement technique that can be achieved using low-cost equipment on a sports field. It is an adaptation of a reflection range measurement and results were compared to control measurements done at an open-area-test-site as well as in an anechoic chamber. This technique was capable of obtaining results with accuracy to within 2 dB for boresight gain and within 2 dB for the main beam of the antenna pattern. Its purpose is not to be highly accurate, but rather to show that it is possible to cost-sensitively introduce students to radio frequency equipment, as well as have access to a pre-characterization test method for inhouse, student-built antennas at tertiary education institutions.
{"title":"A cost-sensitive technique to pre-characterize UHF antennas at tertiary education institutions","authors":"Casey J. Bryant;P. Gideon Wiid","doi":"10.23919/SAIEE.2023.10214186","DOIUrl":"10.23919/SAIEE.2023.10214186","url":null,"abstract":"This article describes an antenna characterization measurement technique that can be achieved using low-cost equipment on a sports field. It is an adaptation of a reflection range measurement and results were compared to control measurements done at an open-area-test-site as well as in an anechoic chamber. This technique was capable of obtaining results with accuracy to within 2 dB for boresight gain and within 2 dB for the main beam of the antenna pattern. Its purpose is not to be highly accurate, but rather to show that it is possible to cost-sensitively introduce students to radio frequency equipment, as well as have access to a pre-characterization test method for inhouse, student-built antennas at tertiary education institutions.","PeriodicalId":42493,"journal":{"name":"SAIEE Africa Research Journal","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/iel7/8475037/10214182/10214186.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44684305","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}
Pub Date : 2023-08-09DOI: 10.23919/SAIEE.2023.10214228
Samantha Woods;Callen Fisher
Thumb loss can diminish one's hand's functionality by up to 40% and the loss of one's entire hand can severely impact a person's ability to perform simple day-to-day tasks. Therefore, there exists a need to focus on the development of a thumb mechanism which supports dexterous grasping activities in anthropomorphic robotic hands. This paper documents the design process of a novel robotic hand, and shows experimental results validating its overall performance. A large focus was placed on developing a novel thumb mechanism which could replicate the thumb's characteristic movement types, namely flexion-extension, abduction-adduction, and oppositionreposition. Additional focus was placed on developing a mechanism for flexion-extension movement of the fingers which did not incorporate passive components and on producing a fully self-contained prototype — with the electronics and actuators contained inside the palm, and the power supply inset against the back of the palm. The hand successfully followed motion commands from a sensor glove, and was able to replicate 14 grasp configurations which demonstrated its dexterous grasping abilities.
{"title":"Development of a self-contained robotic hand with dexterous grasping capabilities for research applications","authors":"Samantha Woods;Callen Fisher","doi":"10.23919/SAIEE.2023.10214228","DOIUrl":"10.23919/SAIEE.2023.10214228","url":null,"abstract":"Thumb loss can diminish one's hand's functionality by up to 40% and the loss of one's entire hand can severely impact a person's ability to perform simple day-to-day tasks. Therefore, there exists a need to focus on the development of a thumb mechanism which supports dexterous grasping activities in anthropomorphic robotic hands. This paper documents the design process of a novel robotic hand, and shows experimental results validating its overall performance. A large focus was placed on developing a novel thumb mechanism which could replicate the thumb's characteristic movement types, namely flexion-extension, abduction-adduction, and oppositionreposition. Additional focus was placed on developing a mechanism for flexion-extension movement of the fingers which did not incorporate passive components and on producing a fully self-contained prototype — with the electronics and actuators contained inside the palm, and the power supply inset against the back of the palm. The hand successfully followed motion commands from a sensor glove, and was able to replicate 14 grasp configurations which demonstrated its dexterous grasping abilities.","PeriodicalId":42493,"journal":{"name":"SAIEE Africa Research Journal","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/iel7/8475037/10214182/10214228.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42831271","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}
Pub Date : 2023-08-09DOI: 10.23919/SAIEE.2023.10214227
Callen Fisher;Dean Pretorius;Nathan Weiss
Humans and animals leverage agility to negotiate the unpredictable environments we occupy. In order for legged robots to leave sterile lab environments, they need to be agile enough to negotiate our lives. Currently, human agility is far superior to the state-of-the-art robotic platforms. Replicating this on robotic platforms require a profound understanding of how contact events are leveraged to complete agile tasks. In line with this aim, this letter was an initial investigation into bipedal turning, to gain insight into how turning was achieved, and to identify any kinematic trends that emerged from the optimization results. This research was conducted on a simulated 10 DoF non-planar bipedal platform with point feet, and made use of a realistic friction cone, and not a linearized approximation. The mathematical model used was based on the bipedal robot currently under development. Two experiments were conducted: rapid turns with a fixed turn angle at varying speeds, and rapid turns with varying turn angles at a fixed speed. Results indicated that slip occurred 93.32% of the contact duration, and turn overshoot was present in all trajectories analyzed. Additionally, a long-time-horizon trajectory was presented to motivate the feasibility and stability of the turn trajectories studied.
{"title":"Initial investigation into bipedal turning: A trajectory optimization study","authors":"Callen Fisher;Dean Pretorius;Nathan Weiss","doi":"10.23919/SAIEE.2023.10214227","DOIUrl":"10.23919/SAIEE.2023.10214227","url":null,"abstract":"Humans and animals leverage agility to negotiate the unpredictable environments we occupy. In order for legged robots to leave sterile lab environments, they need to be agile enough to negotiate our lives. Currently, human agility is far superior to the state-of-the-art robotic platforms. Replicating this on robotic platforms require a profound understanding of how contact events are leveraged to complete agile tasks. In line with this aim, this letter was an initial investigation into bipedal turning, to gain insight into how turning was achieved, and to identify any kinematic trends that emerged from the optimization results. This research was conducted on a simulated 10 DoF non-planar bipedal platform with point feet, and made use of a realistic friction cone, and not a linearized approximation. The mathematical model used was based on the bipedal robot currently under development. Two experiments were conducted: rapid turns with a fixed turn angle at varying speeds, and rapid turns with varying turn angles at a fixed speed. Results indicated that slip occurred 93.32% of the contact duration, and turn overshoot was present in all trajectories analyzed. Additionally, a long-time-horizon trajectory was presented to motivate the feasibility and stability of the turn trajectories studied.","PeriodicalId":42493,"journal":{"name":"SAIEE Africa Research Journal","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/iel7/8475037/10214182/10214227.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45594063","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}
Pub Date : 2023-08-09DOI: 10.23919/SAIEE.2023.10214229
{"title":"Notes for authors","authors":"","doi":"10.23919/SAIEE.2023.10214229","DOIUrl":"https://doi.org/10.23919/SAIEE.2023.10214229","url":null,"abstract":"","PeriodicalId":42493,"journal":{"name":"SAIEE Africa Research Journal","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/iel7/8475037/10214182/10214229.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67845942","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}
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