1. Multiple allocation p-hub location problem for content placement in VoD services: a differential evolution based approachSoumen Atta, Goutam Sen, 2020, original scientific article Abstract: In video-on-demand (VoD) services, large volumes of digital data are kept at hubs which are spatially distributed over large geographic areas and users are connected to these hubs based on their demands. In this article, we consider a large database of video files, that are pre-partitioned to multiple segments based on the demand patterns of users. These segments are restricted to be located only in hubs. Here, users are allowed to be allocated to multiple hubs and all hubs are assumed to be connected with each other. We jointly decide the location of hubs, the placement of segments to these hubs and then the assignment of users to these hubs as per their demand patterns and finally, we find the optimal paths to route the demands of users for different segments having the objective of minimizing the total routing cost. In this article, a differential evolution (DE) based method is proposed to solve the problem. The proposed DE-based method utilizes an efficient function to evaluate the objective value of a candidate solution to the proposed problem. It also incorporates two problem-specific solution refinement techniques for faster convergence. Instances of the problem are generated from the real world movie database and the proposed method is applied to these instances and the performance is evaluated against the benchmark results obtained from CPLEX. Keywords: Video-on-demand (VoD) services, Content distribution networks, Database segment location, Hub location, Multiple hub allocation, Differential evolution (DE), IBM ILOG CPLEX Published in RUNG: 17.04.2023; Views: 525; Downloads: 0 This document has many files! More... |
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6. Hidden periodicity in Stripe 82 with Saraswati supercluster—a fractal analysisVimal Raj, Mohanachandran Nair Sindhu Swapna, Sankaranarayana Iyer Sankararaman, 2021, original scientific article Abstract: The manuscript attempts to explore the periodicity in the distribution of galaxies in the recently
reported Saraswati supercluster and the Stripe 82 region containing it as an example. The report
of 120 Mpc periodicity in the Abell galaxy clusters by power spectrum analysis is the motivation
behind the study. The power spectral analysis across the central part of the Stripe 82 region
shows a periodic variation of 3.09° or 71 Mpc in fractal dimension whereas an average angular
periodicity of 3.45° or 94 Mpc is observed across the Stripe 82 region. This refers to the
periodicity of complexity or cluster density of galaxy distribution. The texture of the distribution
pattern understood through lacunarity analysis indicates a near symmetric distribution. Fractal
dimensions like box-counting dimension, information dimension and correlation dimension are
also found through multifractal analysis. While the information dimension tells about the
distribution density of galactic points, the correlation dimension details the distribution of
galaxies in the neighbourhood Keywords: galaxy distribution, fractal analysis, multifractals, lacunarity, Saraswati supercluster, Stripe 82 Published in RUNG: 04.07.2022; Views: 827; Downloads: 0 This document has many files! More... |
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