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Table of Contents
Reverberation Chamber Low Frequency Field Uniformity Improvement with Conducting Pyramidal Structures
A Comparative Study on the Distance-Optimality for Distance-Preserving Mappings Constructions with Cyclic-Shift Prefix Technique
Modified Earliest Decoding in Networks that Implement Random Linear Network Coding
Investigating the Effects of Subsidy on Network Resource Utilization in Multi-tier Communities
Reverberation Chamber Low Frequency Field Uniformity Improvement with Conducting Pyramidal Structures by M. Roman, R. R. van Zyl, H. C. Reader and J. Andriambeloson
Abstract: Reverberation chambers are commonly used in industry for measuring electromagnetic interference because they are cost-effective. We attempt to stir modes more evenly inside reverberation chambers by introducing passive field uniformity enhancement (PFUE) structures. These structures augment the existing rotating stirrers. Measured results for a 2.445 x 2.475 x 3.72 m reverberation chamber are presented. The results show that the inclusion of passive structures improves the field uniformity in the low 300 - 400 MHz band. The standard deviation of the electric field distribution in this band is improved by up to 0.93 dB. The PFUE structures also reduced the dynamic range, in the worst case, by 2 dB at high frequencies.
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A Comparative Study on the Distance-Optimality for Distance-Preserving Mappings Constructions with Cyclic-Shift Prefix Technique by K. Ouahada, L. Cheng and H. C. Ferreira
Abstract: This paper presents a comparative study on the distance optimality for Distance-Preserving Mappings codes generated from different constructions. Few constructions are considered to investigate the reasons behind making codes optimum when they reach the upper bound on the sum of the Hamming distances for certain lengths of the permutation sequences. The technique of cyclic-shift prefix or suffix of permutation symbols is used to investigate the conditions making distance-preserving mappings codes optimum.
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Modified Earliest Decoding in Networks that Implement Random Linear Network Coding by S. von Solms and A.S.J. Helberg
Abstract: In this paper we present a formalised description of Modified Earliest Decoding. We simulate the performance of the method in comparison with Earliest Decoding in networks that implement random linear network coding. We show that Modified Earliest Decoding has a smaller decoding complexity than Earliest Decoding and Gaussian Elimination as well as a smaller decoding delay.
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Investigating the Effects of Subsidy on Network Resource Utilization in Multi-tier Communities by M. Sumbwanyambe and A. L. Nel
Abstract: One of the main aims of telecommunication subsidies in developing countries is to extend information and communication services to the information “have nots” through subsidized communication services. However, subsidies may have an impact on network resource utilization, Quality of Service (QoS) and the number of users subscribing to an Internet Service Provider (ISP). For example, subsidies may lead to low QoS and high resource utilization while in some instances unsubsidized services may lead to high QoS and low utilization of resources. This see-saw effect may eventually lead to market failure and it may, now and then, destroy market efficiency. Thus far, this phenomenon calls for a combined study, in which the relationship between subsidy, price, QoS and resource utilization is investigated. In this paper, the impact of subsidies on QoS and resource utilization in multi-tier communities is investigated. We try to find a middle ground between implementation of a subsidy discount rate policy for socio-economic development and its effects on QoS and resource utilization in a network.
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