Electrical and Electronic Engineering - Research Publications

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    Intelligent Radio Resource Allocation for Human-Robot Collaboration
    Feng, Y ; Ruan, L ; Nirmalathas, A ; Wong, E (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2022)
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    Novel Spatial Modulation Channel Index Detection in Optical Wireless Communications with Signal Space Diversity
    Song, T ; Wong, E ; Nirmalathas, A ; Alameh, K ; Lim, C ; Wang, K (IEEE, 2020)
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    Mobility-Aware Energy Optimization in Hosts Selection for Computation Offloading in Multi-Access Edge Computing
    Thananjeyan, S ; Chan, CA ; Wong, E ; Nirmalathas, A (Institute of Electrical and Electronics Engineers (IEEE), 2020-07-15)
    Multi-access edge computing (MEC) has been proposed as an approach capable of addressing latency and bandwidth issues in application computation offloading to extend the capabilities beyond the computational and storage limitations of mobile devices. However, there is a critical challenge in MEC to maintain the service continuity between the offloaded user application that is running on the MEC host and the mobile device when a user is moving from radio node to radio node. Furthermore, energy consumption of application computation offloading is an important consideration for MEC service providers in terms of operational costs. Therefore, we formulate the MEC host selection and user application migration problem as a shortest path problem of network energy minimization. We simulate the problem in a hierarchical MEC network deployment environment. We also propose the metric, computational intensity (CI), that can be used by MEC service providers to address the MEC host selection problem. Our results show that with the increment of CI, the selection of MEC hosts tends to move toward level 3 (central deployment) due to energy efficiency and then return to the deployment at level 1 (radio node level) due to latency constraint of the user application. We show that with high accuracy in predicting the user mobility and the available resources in the MEC network, latency- and mobility-aware MEC host selection and user application migration can be pre-calculated to improve response time and energy efficiency.
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    Gigabit/s Optical Wireless Access and Indoor Networks
    Nirmalathas, TA ; Song, T ; Edirisinghe, S ; Tian, L ; Lim, C ; Wong, E ; Wang, K ; Ranaweera, C ; Alameh, K (OSA - Optical Society of America, 2020)
    Optical wireless networks are being explored as a wireless alternative for provision of multi gigabits/second wireless and this paper presents an overview of recent progress and outstanding challenges. and technologies.
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    Estimating Video Popularity From Past Request Arrival Times in a VoD System
    Wang, T ; Jayasundara, C ; Zukerman, M ; Nirmalathas, A ; Wong, E ; Ranaweera, C ; Xing, C ; Moran, B (Institute of Electrical and Electronics Engineers (IEEE), 2020-01-31)
    Efficient provision of Video-on-Demand (VoD) services requires that popular videos are stored in a cache close to users. Video popularity (defined by requested count) prediction is, therefore, important for optimal choice of videos to be cached. The popularity of a video depends on many factors and, as a result, changes dynamically with time. Accurate video popularity estimation that can promptly respond to the variations in video popularity then becomes crucial. In this paper, we analyze a method, called Minimal Inverted Pyramid Distance (MIPD), to estimate a video popularity measure called the Inverted Pyramid Distance (IPD). MIPD requires choice of a parameter, $k$ , representing the number of past requests from each video used to calculate its IPD. We derive, analytically, expressions to determine an optimal value for $k$ , given the requirement on ranking a certain number of videos with specified confidence. In order to assess the prediction efficiency of MIPD, we have compared it by simulations against four other prediction methods: Least Recency Used (LRU), Least Frequency Used (LFU), Least Recently/Frequently Used (LRFU), and Exponential Weighted Moving Average (EWMA). Lacking real data, we have, based on an extensive literature review of real-life VoD system, designed a model of VoD system to provide a realistic simulation of videos with different patterns of popularity variation, using the Zipf (heavy-tailed) distribution of popularity and a non-homogeneous Poisson process for requests. From a large number of simulations, we conclude that the performance of MIPD is, in general, superior to all of the other four methods.