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Proceedings of the 2nd Pan African International Conference on Science, Computing and Telecommunications (PACT 2014)最新文献

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Synchronization of chaotic flows with variable nonlinear hyperbolic functions via hybrid feedback control 基于混合反馈控制的变非线性双曲函数混沌流同步
E. Umoh
The YU-WANG autonomous chaotic system is a three-dimensional system that possesses a quadratic cross-product and a hyperbolic nonlinear term in its system equations. The resulting complex dynamics formed by these nonlinearities can be manipulated to evolve two- and four-wing attractors which form intricate attractors with distinct dynamic properties. This paper presents the synchronization of the system with identical and non-identical hyperbolic nonlinear terms using hybrid feedback control techniques. The results of the various simulations show that the coupled systems are mildly susceptible to varying hyperbolic nonlinearities using the synchronization scheme. However, the folding trajectories are highly sensitive to parametric perturbation in the controller-deactivated architecture of the original system.. The synchronized signals holding possibilities of applications in secure communication system modelling and design.
YU-WANG自治混沌系统是一个具有二次叉积和双曲非线性项的三维系统。这些非线性所形成的复杂动力学可以被操纵成两翼和四翼吸引子,从而形成具有不同动力学性质的复杂吸引子。本文利用混合反馈控制技术,研究了具有相同和非相同双曲型非线性项的系统同步问题。各种仿真结果表明,采用同步方案的耦合系统对变化的双曲型非线性有轻微的敏感性。然而,在原始系统的控制器停用结构中,折叠轨迹对参数摄动高度敏感。同步信号在安全通信系统建模和设计中应用的可能性。
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引用次数: 3
Road map towards eco-efficient cloud computing adoption in higher learning institutions in Tanzania 坦桑尼亚高等院校采用生态高效云计算的路线图
Rodrick Mero, J. Mwangoka
Cloud computing has been trusted in academic environment. Despite the flexibility and cost effective services offered by cloud computing, none of the higher learning institutions in Tanzania (HLIT) has jumped onto the bandwagon. HLIT use traditional computing (TC) that has been proved uneconomical in terms of maintenance and software purchase costs. It is important for HLIT to leverage the low operation costs and flexibility of ICT services offered by cloud computing. The adoption of cloud computing in HLIT need to be examined from the benefits and limitations points of view. Clear adoption stages should be followed to ensure cloud computing services reflect institution's policy and strategy. This work explores TC environment in HLIT towards cloud computing adoption and hence proposes necessary stages for HLIT to move into cloud.
云计算在学术环境中得到了广泛的信任。尽管云计算提供了灵活性和成本效益高的服务,但坦桑尼亚没有一家高等教育机构(HLIT)加入这一潮流。HLIT使用传统计算(TC),在维护和软件购买成本方面已被证明是不经济的。HLIT必须利用云计算提供的信息和通信技术服务的低运营成本和灵活性。在HLIT中采用云计算需要从好处和限制的角度进行审查。应遵循明确的采用阶段,以确保云计算服务反映机构的政策和战略。本工作探讨了HLIT面向云计算采用的TC环境,从而提出了HLIT进入云计算的必要阶段。
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引用次数: 11
Analysis of new crosstalk multiple access systems for inductive communication systems 感应通信系统新型串扰多址系统分析
J. Agbinya
Crosstalk is a major concern which impacts the performance of inductive systems including wireless power transfer, inductive communication systems and embedded inductive powering of biomedical devices. In this paper we seek to show that crosstalk can be either an incentive or a disadvantage if it is not harnessed properly. Therefore we propose as a major contribution a new multiple access system based on crosstalk, the new crosstalk multi-access system (CMAS) for inductive communication channels. To achieve CMAS multiple-input-multiple-output (MIMO) communication is used. Mutual coupling channels are designed to use block coding to identify system nodes and to also decouple the multi-channel responses into orthogonal sources. This provides crosstalk diversity at the receivers. A receiver is able to assemble multiple received signals from multiple sources, eliminating inductive co-channel interference thereby increasing the system signal-to-noise ratio (SNR) and overall system capacity.
串扰是影响感应系统性能的主要问题,包括无线电力传输、感应通信系统和生物医学设备的嵌入式感应供电。在本文中,我们试图表明,如果不适当地利用,相声既可以是一种激励,也可以是一种劣势。因此,我们提出了一种新的基于串扰的多址系统,即用于感应通信信道的新型串扰多址系统(CMAS)。为了实现CMAS的多输入多输出(MIMO)通信。互耦通道被设计成使用分组编码来识别系统节点,并将多通道响应解耦成正交源。这在接收器处提供了串扰分集。接收器能够组装来自多个源的多个接收信号,消除感应共信道干扰,从而增加系统信噪比(SNR)和整体系统容量。
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引用次数: 1
Multifunctional network monitoring system using SMS 采用短信的多功能网络监控系统
A. Kijazi, Michael Kisangiri
Network monitoring is very important for the reliable operation of any network, monitoring is not only concerned with the monitoring of its performance and availability, but also monitoring of network operating environment, because they are both contributing to the reliable operated network. For the effective network monitoring, it is better for Network administrators being intact with both instant network operations as well as different hazards such as fire, water, humidity, power fluctuation and temperature even if they are not physically present in the network operation room. The objective of this paper is to provide an efficient remote Local area Network (LAN) monitoring, mainly focusing on Server room devices and its environment sensors for network administrators.
网络监控对于任何网络的可靠运行都是非常重要的,监控不仅涉及对其性能和可用性的监控,还涉及对网络运行环境的监控,因为它们都有助于网络的可靠运行。为了进行有效的网络监控,最好是网络管理员既能对网络进行即时的操作,也能对火灾、水、湿度、电力波动、温度等不同的危害保持完整,即使这些危害不在网络操作室中。本文的目的是为网络管理员提供一种高效的远程局域网监控,主要针对服务器机房设备及其环境传感器。
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引用次数: 4
Deployment of wireless sensor networks (WSN) in automated irrigation management and scheduling systems: a review 无线传感器网络(WSN)在自动化灌溉管理和调度系统中的应用综述
J. Haule, Kisangiri Michael
Wireless sensor networks (WSN) is an important and exciting technology with great potential for application in various fields including medicine, transportation, agriculture, industrial process control, global-scale environmental monitoring and precision agriculture. This paper reviews the application of WSN in automating irrigation management and rescheduling. Irrigation management and rescheduling based on WSN are potential solutions for optimum water management via automatic access to in-field soil moisture conditions and control of irrigation systems.
无线传感器网络(WSN)是一项重要的、令人兴奋的技术,在医疗、交通、农业、工业过程控制、全球范围的环境监测和精准农业等各个领域具有巨大的应用潜力。本文综述了无线传感器网络在灌溉自动化管理和调度中的应用。基于WSN的灌溉管理和重新调度是通过自动获取田间土壤湿度条件和控制灌溉系统实现最佳水管理的潜在解决方案。
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引用次数: 50
Low-cost tuning of Fuzzy Controllers in a chaotic system stabilization problem 混沌系统镇定问题中模糊控制器的低成本整定
E. Umoh
A heuristic tuning of a Fuzzy Controller to examine the limits of gains that assures a unique control law for stabilization of a Rucklidge chaotic system is presented in this paper. The Rucklidge system is one of the paradigms of chaos that holds possibilities of applications in secure communication schemes and electrical power distribution systems where two identical or hybrid systems can be antisynchronized or synchronized for signal masking over public channels and power outage minimization and control. In this work, a low-cost and less rigorous fuzzy controller tuning strategy is presented where the controller output gain coefficients are tuned within a given bounds to produce unique solutions with better settling times in the context of state vectors stabilization problems. The strategy is less tedious when compared to other tuning methods used for controllers in some chaotic and non-chaotic systems. The approach has been validated on other chaotic systems to be robust for a class of chaotic system control.
本文提出了一种启发式整定模糊控制器来检查增益的极限,以保证Rucklidge混沌系统的稳定具有唯一的控制律。Rucklidge系统是混沌的范例之一,它在安全通信方案和电力分配系统中具有应用的可能性,其中两个相同或混合系统可以反同步或同步,用于公共通道上的信号屏蔽和停电最小化和控制。在这项工作中,提出了一种低成本和不太严格的模糊控制器整定策略,其中控制器输出增益系数在给定的范围内进行整定,从而在状态向量稳定问题中产生具有更好沉降时间的唯一解。在一些混沌和非混沌系统中,与其它用于控制器的整定方法相比,该策略不那么繁琐。该方法已在其他混沌系统上得到验证,对一类混沌系统具有鲁棒性。
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引用次数: 0
Adaptive carrier frequency synchronization using virtual subcarriers in OFDM systems OFDM系统中基于虚拟子载波的自适应载波频率同步
Kwame Ibwe, H. Kundaeli
The inherent immunity of OFDM to multipath limitations comes with the price of increased sensitivity to inaccuracies in the reference frequency. A carrier offset at the OFDM receiver causes losses in subcarrier orthogonality, and thus introduces inter-channel interference (ICI) which degrades the system performance. In mobile communication technology, adaptive algorithms are mostly chosen in real time signal processing because of their high speed to acquire and track changes in parameters. Unfortunately, the existing adaptive methods are not suitable in doubly selective fading channels. In this paper, an adaptive carrier frequency synchronization algorithm is proposed for applications under double dispersive fading channels. The algorithm takes advantage of the known structure of the subspace of OFDM signals. It is shown that the mean square errors of frequency offset estimates are much lower than those of existing adaptive and some non-adaptive algorithms. Simulations also show that it takes only one symbol for the proposed algorithm to track the changes in the channel, leading to high accuracy in the compensation. Since no matrix inversion is involved in the algorithm, excellent transient behaviors with very low complexity are obtained. The proposed algorithm is robust and outperforms the existing adaptive algorithms particularly in doubly dispersive channels.
OFDM固有的抗多径限制的代价是对参考频率误差的灵敏度增加。OFDM接收端的载波偏移会导致子载波正交性的损失,从而引入信道间干扰(ICI),从而降低系统性能。在移动通信技术中,实时信号处理多采用自适应算法,因为自适应算法能够快速地获取和跟踪参数的变化。然而,现有的自适应方法不适用于双选择性衰落信道。提出了一种适用于双色散衰落信道的自适应载波同步算法。该算法充分利用了OFDM信号子空间的已知结构。结果表明,频率偏移估计的均方误差远低于现有的自适应算法和一些非自适应算法。仿真结果表明,该算法只需要一个符号即可跟踪信道的变化,补偿精度高。由于该算法不涉及矩阵反演,因此获得了复杂度极低的优良暂态行为。该算法鲁棒性好,在双色散信道中性能优于现有的自适应算法。
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引用次数: 0
Monitoring and evaluation of the e-readers project in rural Tanzania 监测和评价坦桑尼亚农村的电子阅读器项目
D. Machuve, I. Zlotnikova, D. Nyambo
This study provides recommendations on the monitoring and evaluation conducted for an ICT in Education project in two rural primary schools in Tanzania. The objective of the study was to evaluate the effectiveness of e-readers introduction at the schools. The e-readers introduction aimed at complementing the traditional print books. Print books are insufficient in primary schools in Tanzania; this ultimately leads to lack of reading skills in pupils and poor overall academic performance. As a conceptual framework the study adopted the InfoDev Monitoring and Evaluation framework for ICT in Education projects and adjusted it to local conditions. The study has shown that pupils at both schools considerably improved their reading skills as a result of the e-readers introduction. The introduction of e-readers also resulted in teachers and pupils being more motivated and engaged in learning. Survey results for parents demonstrate readiness on cost-sharing for acquiring the devices. This also indicates the feasibility of up-scaling the project to other schools in the country.
本研究为坦桑尼亚两所农村小学的信息和通信技术教育项目的监测和评价提供了建议。本研究的目的是评估在学校引进电子阅读器的效果。电子阅读器的引入旨在补充传统的纸质书。坦桑尼亚小学的纸质书不足;这最终导致学生缺乏阅读技能,整体学习成绩不佳。作为一个概念框架,研究采用了教育资讯及通讯科技项目的资讯发展监察及评估框架,并根据本地情况作出调整。研究表明,两所学校的学生在引进电子阅读器后,阅读能力都有了很大的提高。电子阅读器的引入也使教师和学生更有动力,更投入到学习中。针对家长的调查结果表明,他们愿意分担购买这些设备的费用。这也表明将该项目扩大到该国其他学校的可行性。
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引用次数: 5
Implementing wireless network performance optimization for Small and Medium Enterprises 为中小企业实现无线网络性能优化
Topside E. Mathonsi, Okuthe P. Kogeda
There is a high growth rate in number of Small and Medium Enterprises (SMEs) in South Africa and the role they play in the growth of South African economy is very vital. These organizations set up networks to ease communication and share resources. However, due to rapid growth in most of the SMEs, they face network performance limitations including high link congestion, intermediate node loss, high end-to-end delay and poor Quality of Service (QoS). These limitations lead to poor network performance, because a more reliable path is not selected before packet transmission starts and the available bandwidth is properly allocated between communicating users. In this paper, we designed and implemented an enhanced bandwidth sharing scheme by integrating cooperative game theory, multiple routing metrics and standard-Dijkstra algorithm, in order to reduce link congestion, end-to-end delay and minimize number of packets lost during transmission. The enhanced bandwidth sharing scheme first select a more reliable path then allocate the available bandwidth between communicating users based on the packet size they want to send at a particular time. The Network Simulator 2 (NS2) simulation results showed that the enhanced bandwidth sharing scheme produced the desired QoS and there is high bandwidth utilization. It also reduced link congestion, end-to-end delay and minimized number of packets lost at various packet sizes.
南非的中小企业(SMEs)数量增长率很高,它们在南非经济增长中发挥的作用非常重要。这些组织建立网络以方便交流和共享资源。然而,由于大多数中小企业的快速增长,它们面临着网络性能的限制,包括高链路拥塞、中间节点丢失、高端到端延迟和低服务质量(QoS)。这些限制导致网络性能较差,因为在开始数据包传输之前没有选择更可靠的路径,并且在通信用户之间合理分配可用带宽。为了减少链路拥塞、端到端延迟和减少传输过程中的丢包数,结合合作博弈理论、多路由度量和标准dijkstra算法,设计并实现了一种增强型带宽共享方案。增强型带宽共享方案首先选择一条更可靠的路径,然后根据通信用户在特定时间想要发送的数据包大小在用户之间分配可用带宽。网络模拟器2 (Network Simulator 2, NS2)的仿真结果表明,增强的带宽共享方案能够产生期望的QoS,并且具有较高的带宽利用率。它还减少了链路拥塞、端到端延迟,并最大限度地减少了各种数据包大小的数据包丢失数量。
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引用次数: 7
Scale factor considerations for SDF technique SDF技术的尺度因子考虑
Thanh T. Nguyen, J. Devlin, D. Elton, E. Custovic, B. Bienvenu
The Tasman International Geospace Environment Radars (TIGER) form part of an international network of similar HF radars called Super Dual Auroral Radar Network (SuperDARN) which explore the impact of solar disturbances on Earth. These radars utilise an Auto Correlation Function (ACF) to measure the changing phase of the ACF between lag times to determine the Doppler frequency and the target velocity.With the development of TIGER-3, an all digital radar platform, a novel method of determining target velocities has been proposed. In the proposed methoThe Tasman International Geospace Environment Radars (TIGER) form part of an international network of similar HF radars called Super Dual Auroral Radar Network (SuperDARN) which explore the impact of solar disturbances on Earth. These radars utilise an Auto Correlation Function (ACF) to measure the changing phase of the ACF between lag times to determine the Doppler frequency and the target velocity.With the development of TIGER-3, an all digital radar platform, a novel method of determining target velocities has been proposed. In the proposed method, a comparison of the transmit and receive signal magnitude spectrums is performed to determine the Spectrum Difference Function (SDF). The gradient of SDF in the vicinity of the carrier frequency is calculated, from this value the Doppler Frequency Shift fd can be deduced. The result is then multiplied by a precalculated Scale Factor which is necessary to compensate for the systematic error due to the method. This paper will address all the factors which have influence on the value of Scale Factor, therefore minimize the error associated with the process of calculating Scale Factor.d, a comparison of the transmit and receive signal magnitude spectrums is performed to determine the Spectrum Difference Function (SDF). The gradient of SDF in the vicinity of the carrier frequency is calculated, from this value the Doppler Frequency Shift fd can be deduced. The result is then multiplied by a precalculated Scale Factor which is necessary to compensate for the systematic error due to the method. This paper will address all the factors which have influence on the value of Scale Factor, therefore minimize the error associated with the process of calculating Scale Factor.
塔斯曼国际地球空间环境雷达(TIGER)是一个名为超级双极光雷达网(superdam)的类似高频雷达国际网络的一部分,该网络探索太阳扰动对地球的影响。这些雷达利用自相关函数(ACF)来测量ACF在滞后时间之间的相位变化,以确定多普勒频率和目标速度。随着全数字雷达平台TIGER-3的发展,提出了一种确定目标速度的新方法。在提出的方法中,塔斯曼国际地球空间环境雷达(TIGER)是一个类似的高频雷达国际网络的一部分,该网络被称为超级双极光雷达网络(superdam),用于探索太阳扰动对地球的影响。这些雷达利用自相关函数(ACF)来测量ACF在滞后时间之间的相位变化,以确定多普勒频率和目标速度。随着全数字雷达平台TIGER-3的发展,提出了一种确定目标速度的新方法。在该方法中,通过比较发射和接收信号的幅值频谱来确定频谱差函数(SDF)。计算载波频率附近SDF的梯度,由此可以推导出多普勒频移fd。然后将结果乘以预先计算的比例因子,该比例因子是补偿该方法引起的系统误差所必需的。本文将解决所有影响尺度因子值的因素,从而最大限度地减少与计算尺度因子过程中的误差。d,对发射和接收信号的幅度频谱进行比较,以确定频谱差函数(SDF)。计算载波频率附近SDF的梯度,由此可以推导出多普勒频移fd。然后将结果乘以预先计算的比例因子,该比例因子是补偿该方法引起的系统误差所必需的。本文将解决所有影响尺度因子值的因素,从而最大限度地减少与计算尺度因子过程中的误差。
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引用次数: 2
期刊
Proceedings of the 2nd Pan African International Conference on Science, Computing and Telecommunications (PACT 2014)
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