Evaluation Of Partitioning Schemes Of The Nested Partitions Method In The Context Of Simulation Based Optimization

Author : Nejat Arinik
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (127 download)

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Download or read book Multiplicity in the Partitioning of Signed Graphs written by Nejat Arinik and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: According to the structural balance theory, a signed graph is considered structurally balanced when it can be partitioned into a number of modules such that positive edges are located inside the modules and negatives ones are in-between them. In practice, real-world networks are rarely perfectly balanced. When it is not the case, one wants to measure the magnitude of the imbalance and to identify the set of edges related to the network imbalance. The Correlation Clustering (CC) problem is precisely defined as finding the partition with minimal imbalance. Signed graph partitioning is an important task, which has many applications, as finding a balanced partition helps understanding the system modeled by the graph. However, the standard approach used in the literature is to find a single partition and focus the rest of the analysis on it, as if it was sufficient to fully characterize the studied system. Yet, it may not reflect the meso-structure of the network, and one may need to seek for other partitions to build a better picture. Although this need to look for multiplicity is extremely important from the end user's perspective, only a very few works took it into consideration in their analysis, up to now. In this thesis, we want to relax this traditional single-partition assumption to allow searching for multiple partitions in two separate situations. The first one arises in the context of signed multiplex networks. All traditional approaches proposed to partition multiplex networks in general are based on the single-partition assumption. To overcome this limitation, we propose a new partitioning method that integrates a meta-clustering process before merging the partitions of individual layers, which allows identifying structurally similar layers. The second situation is specific to the CC problem. When solving an instance of such problem, several or even many optimal partitions may coexist. If multiple optimal partitions coexist, one can then wonder how different/diverse they are. Put differently, we want to know what we loose when considering only one partition, while there might be multiple ones. In order to answer these questions, one should ideally enumerate completely the space of optimal partitions, and perform its analysis. To this end, we propose a new efficient solution space enumeration method and a cluster analysis-based framework in order to first enumerate the space of optimal partitions and then empirically study such space. Lastly, each of these previous situations requires to compute the similarity between partitions. In the context of graph partitioning, this task can be done through a so-called external evaluation measure. However, there exist many such measures, each having different characteristics. This makes it challenging to select the most appropriate for a given situation for the end user. To this end, we propose a new empirical evaluation framework in order to produce results that end users can easily interpret. For a collection of candidate measures, it first consists in describing their behavior by computing them for a generated dataset of parametric partitions, obtained by applying a set of predefined parametric partition transformations. Second, our framework characterizes the measures in terms of how they are affected by these parameters and transformations.