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Modelling and simulation of adaptive frequency relaying for distributed generation 分布式发电自适应频率继电器的建模与仿真
2013 Africon Pub Date : 2013-09-01 DOI: 10.1109/AFRCON.2013.6757837
C. Buque, S. Chowdhury, S. Chowdhury
{"title":"Modelling and simulation of adaptive frequency relaying for distributed generation","authors":"C. Buque, S. Chowdhury, S. Chowdhury","doi":"10.1109/AFRCON.2013.6757837","DOIUrl":"https://doi.org/10.1109/AFRCON.2013.6757837","url":null,"abstract":"Modern utilities around the world have started the implementation of small scale local generation to support power supply. Introduction of distributed generation presents new challenges and opportunities for electrical engineers. One of the challenges is the change of network electrical characteristics. Network regulators have accommodated these changes in Grid Codes. One of the recent regulations is such that, the allowable system frequency variation changes according to mode of Microgrid operation. This poses a challenge to frequency protection engineers because currently frequency relays are non-adaptive, they operate based on fixed limits and thresholds for operation. An adaptive relay that can change its settings to suit the mode of Microgrid operation is advantageous. This paper presents an adaptive frequency relay model that can automatically change its settings to accommodate both modes of operation.","PeriodicalId":159306,"journal":{"name":"2013 Africon","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129270249","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: 2
Measurement of loss mechanisms in microwave coaxial resonator filters 微波同轴谐振器滤波器损耗机制的测量
2013 Africon Pub Date : 2013-09-01 DOI: 10.1109/AFRCON.2013.6757636
S. Maas, P. Meyer, P. V. D. Walt
{"title":"Measurement of loss mechanisms in microwave coaxial resonator filters","authors":"S. Maas, P. Meyer, P. V. D. Walt","doi":"10.1109/AFRCON.2013.6757636","DOIUrl":"https://doi.org/10.1109/AFRCON.2013.6757636","url":null,"abstract":"Various loss mechanisms in microwave coaxial resonators are investigated through measurement. The effects of structure, manufacturing techniques, polishing techniques and plating on the Q-factor are compared for an S-band resonator. It is experimentally established that wire-cutting followed by silver plating results in the highest Q-values, which are also comparable with simulation results.","PeriodicalId":159306,"journal":{"name":"2013 Africon","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116865755","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: 2
Characterization of the polarization mode dispersion of single mode fibre in KAT-7 telescope array network, South Africa 南非KAT-7望远镜阵列网络中单模光纤偏振模色散特性
2013 Africon Pub Date : 2013-09-01 DOI: 10.1109/AFRCON.2013.6757860
E. K. Kipnoo, H. Kourouma, R. Gamatham, A. Leitch, T. Gibbon, R. Julie, R. Siebrits, F. Kapp
{"title":"Characterization of the polarization mode dispersion of single mode fibre in KAT-7 telescope array network, South Africa","authors":"E. K. Kipnoo, H. Kourouma, R. Gamatham, A. Leitch, T. Gibbon, R. Julie, R. Siebrits, F. Kapp","doi":"10.1109/AFRCON.2013.6757860","DOIUrl":"https://doi.org/10.1109/AFRCON.2013.6757860","url":null,"abstract":"We experimentally investigate the differential group delay (DGD) in KAT-7 optical fibre network using polametric measurement technique. Low PMD values in the femtosecond range are obtained over the 10 km single mode fibre. It is also established that deployment of the fibre alters the DGD of the network. This study is paramount in ensuring accurate and stable clock signal as well as error free transmission at very high bit rates in the optical network.","PeriodicalId":159306,"journal":{"name":"2013 Africon","volume":"259 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114172990","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: 2
Modeling and control of the offshore wind energy system based on 5MW DFIG connected to grid 基于5MW DFIG并网的海上风电系统建模与控制
2013 Africon Pub Date : 2013-09-01 DOI: 10.1109/AFRCON.2013.6757850
M. S. Camara, M. Camara, B. Dakyo, H. Gualous
{"title":"Modeling and control of the offshore wind energy system based on 5MW DFIG connected to grid","authors":"M. S. Camara, M. Camara, B. Dakyo, H. Gualous","doi":"10.1109/AFRCON.2013.6757850","DOIUrl":"https://doi.org/10.1109/AFRCON.2013.6757850","url":null,"abstract":"This paper presents the control strategies of an offshore wind energy system based on 5MW Doubly Fed Induction Generator (DFIG). The DFIG seems to be interesting for such high power wind generator systems. The proposed control strategies include the Maximum Power Tracking (MPPT) for the DFIG speed control, the active/reactive power control, and the DC-bus voltage control method. To show the performances of the control strategies, some simulation results are presented and analyzed using Matlab/Simulink software.","PeriodicalId":159306,"journal":{"name":"2013 Africon","volume":"197 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114662397","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: 15
Recursive MMSE-based iterative channel estimation for OFDM-IDMA systems 基于递归 MMSE 的 OFDM-IDMA 系统迭代信道估计
2013 Africon Pub Date : 2013-09-01 DOI: 10.1109/AFRCON.2013.6757863
O. Oyerinde, S. Mneney
{"title":"Recursive MMSE-based iterative channel estimation for OFDM-IDMA systems","authors":"O. Oyerinde, S. Mneney","doi":"10.1109/AFRCON.2013.6757863","DOIUrl":"https://doi.org/10.1109/AFRCON.2013.6757863","url":null,"abstract":"Combination of IDMA with Orthogonal Frequency Division Multiplexing (OFDM) transmission technique to form OFDM-IDMA system has been considered as a better option to Multicarrier-CDMA (MC-CDMA) systems. However, as the case with other multiple access schemes-based communication systems, availability of accurate estimate of channel state information (CSI) at the receiver end of the system remains a crucial factor for optimum performance of the OFDM-IDMA systems. In this paper we propose a linear algorithm for the implementation of the iterative channel estimation schemes OFDM-IDMA systems. In the scheme, a recursive minimum mean square error (RMMSE) algorithm is employed for the iterative channel estimation. The achievable results associated with the proposed RMMSE-based iterative channel estimator are documented in comparison with results associated with iterative channel estimator employing Least Mean Square (LMS), Normalized Least Mean Square (NLMS), and Variable Step Size Normalized Least Mean Square (VSSNLMS) algorithms. From the simulation results, it is evident that the proposed RMMSE-based iterative channel estimator outperforms the estimator based on the adaptive algorithms.","PeriodicalId":159306,"journal":{"name":"2013 Africon","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126094426","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: 6
Probabilistic object and viewpoint models for active object recognition 主动目标识别的概率目标和视点模型
2013 Africon Pub Date : 2013-09-01 DOI: 10.1109/AFRCON.2013.6757598
N. Govender, J. Warrell, Philip H. S. Torr, F. Nicolls
{"title":"Probabilistic object and viewpoint models for active object recognition","authors":"N. Govender, J. Warrell, Philip H. S. Torr, F. Nicolls","doi":"10.1109/AFRCON.2013.6757598","DOIUrl":"https://doi.org/10.1109/AFRCON.2013.6757598","url":null,"abstract":"For mobile robots to perform certain tasks in human environments, fast and accurate object verification and recognition is essential. Bayesian approaches to active object recognition have proved effective in a number of cases, allowing information across views to be integrated in a principled manner, and permitting a principled approach to data acquisition. Existing approaches however mostly rely on probabilistic models which make simplifying assumptions such as that features may be treated independently and that objects will appear without clutter at test time. We develop a number of probabilistic object and viewpoint models which are explicitly designed to cope with situations in which these assumptions fail, and show these to perform well in a Bayesian active recognition setting using test data in which objects appear in cluttered environments with significant occlusion.","PeriodicalId":159306,"journal":{"name":"2013 Africon","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126717681","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
Chaos synchronization on Visible Light Communication with application for secure data communications 可见光通信中的混沌同步及其在安全数据通信中的应用
2013 Africon Pub Date : 2013-09-01 DOI: 10.1109/AFRCON.2013.6757743
P. Canyelles-Pericas, A. Burton, H. Le‐Minh, Zabih Ghassemlooy, K. Busawon
{"title":"Chaos synchronization on Visible Light Communication with application for secure data communications","authors":"P. Canyelles-Pericas, A. Burton, H. Le‐Minh, Zabih Ghassemlooy, K. Busawon","doi":"10.1109/AFRCON.2013.6757743","DOIUrl":"https://doi.org/10.1109/AFRCON.2013.6757743","url":null,"abstract":"This paper studies the possibility of implementing a chaos synchronization scheme in the context of Visible Light Communication (VLC) with potential application to message encryption. For this, a unidirectional transmitter-receiver configuration is employed whereby the encrypted data is sent over a VLC optical wireless channel. More precisely, the classical chaotic masking, with the use of a Rossler oscillator and a corresponding nonlinear observer, and the inverse system approach with Lorenz oscillators, have been employed to demonstrate the proof of concept of chaos synchronization in VLC. By employing a pseudo random binary data sequence as a message it is shown that acceptable message recovery is obtained despite the presence of delay, attenuation and noise in the channel. Simulations results using Matlab Simulink are provided to show the performance and the level of the synchronization achieved for both methods.","PeriodicalId":159306,"journal":{"name":"2013 Africon","volume":"82 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126287233","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: 9
RHINO Cluster Control and management system RHINO集群控制与管理系统
2013 Africon Pub Date : 2013-09-01 DOI: 10.1109/AFRCON.2013.6757640
V. Chiriseri, S. Winberg, S. Rajan
{"title":"RHINO Cluster Control and management system","authors":"V. Chiriseri, S. Winberg, S. Rajan","doi":"10.1109/AFRCON.2013.6757640","DOIUrl":"https://doi.org/10.1109/AFRCON.2013.6757640","url":null,"abstract":"The objective of this paper is to present the RHINO ARM API Cluster Control System (RAACMS) that will enable a user to access and control networked Reconfigurable Hardware Interface for computing and radio (RHINO) platforms. The framework is designed to run on a reconfigurable platforms consisting of FPGA and an ARM processor connected in a cluster. This system is built around a client-server design, and includes an API on the ARM and control PC, that enables users to execute their code on the control PC and control and change variables on a cluster of RHINO platforms. This paper will present the design and implementation of the RAACMS on the cluster of RHINOs at the University of Cape Town. Tests are performed on a prototype version of the framework. The conclusions discuss uses of the systems, together with further plans for improving the framework.","PeriodicalId":159306,"journal":{"name":"2013 Africon","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126330374","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 colour image watermarking technique resistant to affine geometric attacks 一种抗仿射几何攻击的彩色图像水印技术
2013 Africon Pub Date : 2013-09-01 DOI: 10.1109/AFRCON.2013.6757681
Felix O. Owalla, E. Mwangi
{"title":"A colour image watermarking technique resistant to affine geometric attacks","authors":"Felix O. Owalla, E. Mwangi","doi":"10.1109/AFRCON.2013.6757681","DOIUrl":"https://doi.org/10.1109/AFRCON.2013.6757681","url":null,"abstract":"This paper presents a colour image watermarking scheme resistant to affine geometric distortions. The technique involves embedding of the watermark in the host image in the Discrete Cosine Transform (DCT) domain in a spread-spectrum format. Harris corner detector based feature-points are then employed to get Delaunay triangulation which is used to reverse geometric attacks before attempting to extract the watermark. In some instances the geometric attack may lead to loss of feature-points resulting in the recovery of low quality watermark. In this paper we propose a scheme of estimating geometric attacks by taking the mean of selected triangles in the Delaunay tessellation. Computer simulation using MATLAB has been used to show the robustness of the proposed scheme.","PeriodicalId":159306,"journal":{"name":"2013 Africon","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130585294","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: 2
A small-plant PID temperature controller for thermoluminescence measurement 用于热释光测量的小型工厂PID温度控制器
2013 Africon Pub Date : 2013-09-01 DOI: 10.1109/AFRCON.2013.6757856
R. Ocaya, Mduduzi Mbongo
{"title":"A small-plant PID temperature controller for thermoluminescence measurement","authors":"R. Ocaya, Mduduzi Mbongo","doi":"10.1109/AFRCON.2013.6757856","DOIUrl":"https://doi.org/10.1109/AFRCON.2013.6757856","url":null,"abstract":"An integral part of thermoluminescence (TL) measurement system is a temperature controller. Many of the low-cost TL instruments surveyed employ open-loop methods based on external, discrete components to control the temperature of the sample. The repeatability of one such method was found to be low. The motivation for the present implementation was to exert fine and repeatable heating by including temperature feedback. The plant was first modeled mathematically and then simulated with MATLAB. A digital control algorithm was then derived from the simulation results. The completed system uses the PIC18f2520 to implement the digital pulse-width modulation (PWM) closed-loop temperature control with minimum resolution of ±0.5°C. The linear temperature ramping performance of the constructed PID controller was verified over the temperature range of 100°C to 400°C.","PeriodicalId":159306,"journal":{"name":"2013 Africon","volume":"81 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123094178","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: 2
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