Journal of Combinatorial Optimization最新文献

{"title":"Social media actors: perception and optimization of influence across different types","authors":"Alexander A. Kharlamov, Aleksey N. Raskhodchikov, Maria Pilgun","doi":"10.1007/s10878-024-01238-3","DOIUrl":"https://doi.org/10.1007/s10878-024-01238-3","url":null,"abstract":"<p>The paper deals with the analysis of the communicative behavior of various types of actors, speech perception and optimization of influence based on social media data and is an extended version of the report presented at CSoNet 2020 and published based on the deliverables of the conference. The paper proposes an improved methodology that is tested on the new material of conflicts regarding urban planning. The research was conducted on the material of social media concerning the construction of the South-East Chord in Moscow (Russia). The study involved a cross-disciplinary approach using neural network technologies, complex networks analysis. The dataset included social networks, microblogs, forums, blogs, videos, reviews. This paper presents the semantic model for the influence maximization analysis in social networks using neural network technologies, also proposed a variant of analyzing the situation with individual and collective actors, multiple opinion leaders, with a dynamic transformation of the hierarchy and ratings according to various parameters.</p>","PeriodicalId":50231,"journal":{"name":"Journal of Combinatorial Optimization","volume":"107 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2025-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142990260","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optimal dispatching of electric vehicles based on optimized deep learning in IoT","authors":"V. Agalya, M. Muthuvinayagam, R. Gandhi","doi":"10.1007/s10878-024-01251-6","DOIUrl":"https://doi.org/10.1007/s10878-024-01251-6","url":null,"abstract":"<p>Recent years have witnessed a growing trend in the utilization of Electric Vehicles (EVs), however with the increased usage of EVs, appropriate strategies for supporting the charging demands has not garnered much attention. The absence of adaptable plans in charging may result in minimized participation; further, the charging demands have to be addressed with utmost care for ensuring reliability and efficiency of the grid. In this paper, an efficient EV charging technique based on blockchain based user transaction and smart contract is devised. Here, charge scheduling is performed by acquiring the information the charging demand of the EV over Internet of things. In case the EV does not have sufficient power to reach the target, nearest Charging Station (CS) with the minimal electricity price is identified. The CS is selected considering various factors, such average waiting time, distance, power, traffic, and so on. Here, power prediction is performed using the Deep Maxout Network (DMN), whose weights are adapted based on the devised Exponentially Snake Optimization (ESO) algorithm. Furthermore, the efficacy of the devised ESO-DMN is examined considering metrics, like average waiting time, distance, and number of EVs charged and power and is found to have attained values of 1.937 s, 13.952 km, 55 and 2.876 J.</p>","PeriodicalId":50231,"journal":{"name":"Journal of Combinatorial Optimization","volume":"15 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2024-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142888180","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Lollipop and cubic weight functions for graph pebbling","authors":"Marshall Yang, Carl Yerger, Runtian Zhou","doi":"10.1007/s10878-024-01248-1","DOIUrl":"https://doi.org/10.1007/s10878-024-01248-1","url":null,"abstract":"<p>Given a configuration of pebbles on the vertices of a graph <i>G</i>, a pebbling move removes two pebbles from a vertex and puts one pebble on an adjacent vertex. The pebbling number of a graph <i>G</i> is the smallest number of pebbles required such that, given an arbitrary initial configuration of pebbles, one pebble can be moved to any vertex of <i>G</i> through some sequence of pebbling moves. Through constructing a non-tree weight function for <span>(Q_4)</span>, we improve the weight function technique, introduced by Hurlbert and extended by Cranston et al., that gives an upper bound for the pebbling number of graphs. Then, we propose a conjecture on weight functions for the <i>n</i>-dimensional cube. We also construct a set of valid weight functions for variations of lollipop graphs, extending previously known constructions.</p>","PeriodicalId":50231,"journal":{"name":"Journal of Combinatorial Optimization","volume":"132 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2024-12-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142884405","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optimal blocks for maximizing the transaction fee revenue of Bitcoin miners","authors":"Mohsen Alambardar Meybodi, Amir Goharshady, Mohammad Reza Hooshmandasl, Ali Shakiba","doi":"10.1007/s10878-024-01249-0","DOIUrl":"https://doi.org/10.1007/s10878-024-01249-0","url":null,"abstract":"<p>In this work, we consider a combinatorial optimization problem with direct applications in blockchain mining, namely finding the most lucrative blocks for Bitcoin miners, and propose optimal algorithmic solutions. Our experiments show that our algorithms increase the miners’ revenues by more than a million dollars per month. Modern blockchains reward their miners in two ways: (i) a base reward for each block that is mined, and (ii) the transaction fees of those transactions that are included in the mined block. The base reward is fixed by the respective blockchain’s protocol and is not under the miner’s control. Hence, for a miner who wishes to maximize earnings, the fundamental problem is to form a valid block with maximal total transaction fees and then try to mine it. Moreover, in many protocols, including Bitcoin itself, the base reward halves at predetermined intervals, hence increasing the importance of maximizing transaction fees and mining an optimal block. This problem is further complicated by the fact that transactions can be prerequisites of each other or have conflicts (in case of double-spending). In this work, we consider the problem of forming an optimal block, i.e. a valid block with maximal total transaction fees, given a set of unmined transactions. On the theoretical side, we first formally model our problem as an extension of <span>Knapsack</span> and then show that, unlike classical <span>Knapsack</span>, our problem is strongly NP-hard. We also show a hardness-of-approximation result. As such, there is no hope in solving it efficiently for general instances. However, we observe that its real-world instances are quite sparse, i.e. the transactions have very few dependencies and conflicts. Using this fact, and exploiting three well-known graph sparsity parameters, namely treedepth, treewidth and pathwidth, we present exact linear-time parameterized algorithms that are applicable to the real-world instances and obtain optimal results. On the practical side, we provide an extensive experimental evaluation demonstrating that our approach vastly outperforms the current Bitcoin miners in practice, obtaining a significant per-block average increase of 11.34 percent in transaction fee revenues which amounts to almost one million dollars per month.\u0000</p>","PeriodicalId":50231,"journal":{"name":"Journal of Combinatorial Optimization","volume":"263 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2024-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142858386","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Discrete circles: analytical definition and generation in the hexagonal grid","authors":"Rita Zrour, Lidija Čomić, Eric Andres, Gaëlle Largeteau Skapin","doi":"10.1007/s10878-024-01246-3","DOIUrl":"https://doi.org/10.1007/s10878-024-01246-3","url":null,"abstract":"<p>We propose an analytical definition of discrete circles in the hexagonal grid. Our approach is based on a non-constant thickness function. We determine the thickness using the (edge and vertex) flake model. Both types of circles are connected. We prove that edge flake circles are without simple points for integer radii. Incremental generation algorithms are deduced from the analytical characterization of both edge and vertex flake circles. We compare our approach with existing algorithms for the circle generation on the hexagonal grid. Our approach offers simpler algorithm and an analytical characterization that the other algorithms do not offer. The benefit of an analytical characterization is that it makes the question of the membership of a point to a primitive trivial.</p>","PeriodicalId":50231,"journal":{"name":"Journal of Combinatorial Optimization","volume":"7 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2024-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142858338","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Online multiple one way non-preemptive time series search with interrelated prices","authors":"Jinghan Zhao, Yongxi Cheng, Jan Eube, Haodong Liu","doi":"10.1007/s10878-024-01247-2","DOIUrl":"https://doi.org/10.1007/s10878-024-01247-2","url":null,"abstract":"<p>This paper studies the online multiple time series search problem with interrelated prices (MTSS-ip). This perspective narrows the distance between the problem and the reality of market prices with limited variation. In MTSS-ip, the products arrive periodically, and the decision maker has a limited storage size without knowing future prices. The prices of two adjacent periods are interrelated. This study proposes an online zero-inventory algorithm (ZIA) and proves an upper bound of <span>(K+1-frac{K}{theta _2})</span> on the competitive ratio of ZIA. In addition, a lower bound on the competitive ratio of problem MTSS-ip for any deterministic online algorithm is established. For the case with a large storage size <i>K</i>, a lower bound of <span>(frac{K}{48log _{theta _2} K})</span> on the competitive ratio for MTSS-ip is proved.</p>","PeriodicalId":50231,"journal":{"name":"Journal of Combinatorial Optimization","volume":"27 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142832113","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Facial expression-based emotion recognition across diverse age groups: a multi-scale vision transformer with contrastive learning approach","authors":"G. Balachandran, S. Ranjith, T. R. Chenthil, G. C. Jagan","doi":"10.1007/s10878-024-01241-8","DOIUrl":"https://doi.org/10.1007/s10878-024-01241-8","url":null,"abstract":"<p>Facial expression-based Emotion Recognition (FER) is crucial in human–computer interaction and affective computing, particularly when addressing diverse age groups. This paper introduces the Multi-Scale Vision Transformer with Contrastive Learning (MViT-CnG), an age-adaptive FER approach designed to enhance the accuracy and interpretability of emotion recognition models across different classes. The MViT-CnG model leverages vision transformers and contrastive learning to capture intricate facial features, ensuring robust performance despite diverse and dynamic facial features. By utilizing contrastive learning, the model's interpretability is significantly enhanced, which is vital for building trust in automated systems and facilitating human–machine collaboration. Additionally, this approach enriches the model's capacity to discern shared and distinct features within facial expressions, improving its ability to generalize across different age groups. Evaluations using the FER-2013 and CK + datasets highlight the model's broad generalization capabilities, with FER-2013 covering a wide range of emotions across diverse age groups and CK + focusing on posed expressions in controlled environments. The MViT-CnG model adapts effectively to both datasets, showcasing its versatility and reliability across distinct data characteristics. Performance results demonstrated that the MViT-CnG model achieved superior accuracy across all emotion recognition labels on the FER-2013 dataset with a 99.6% accuracy rate, and 99.5% on the CK + dataset, indicating significant improvements in recognizing subtle facial expressions. Comprehensive evaluations revealed that the model's precision, recall, and F1-score are consistently higher than those of existing models, confirming its robustness and reliability in facial emotion recognition tasks.</p>","PeriodicalId":50231,"journal":{"name":"Journal of Combinatorial Optimization","volume":"21 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142832112","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spectral influence in networks: an application to input-output analysis","authors":"Nizar Riane","doi":"10.1007/s10878-024-01244-5","DOIUrl":"https://doi.org/10.1007/s10878-024-01244-5","url":null,"abstract":"<p>This paper introduces the concepts of spectral influence and spectral cyclicality, both derived from the largest eigenvalue of a graph’s adjacency matrix. These two novel centrality measures capture both diffusion and interdependence from a local and global perspective respectively. We propose a new clustering algorithm that identifies communities with high cyclicality and interdependence, allowing for overlaps. To illustrate our method, we apply it to input-output analysis within the context of the Moroccan economy.</p>","PeriodicalId":50231,"journal":{"name":"Journal of Combinatorial Optimization","volume":"85 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142832114","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Np-completeness and bounds for disjunctive total domination subdivision","authors":"Canan Çiftçi, Aysun Aytaç","doi":"10.1007/s10878-024-01245-4","DOIUrl":"https://doi.org/10.1007/s10878-024-01245-4","url":null,"abstract":"<p>A subset <span>( Ssubseteq V(G) )</span>, where <i>V</i>(<i>G</i>) is the vertex set of a graph <i>G</i>, is a disjunctive total dominating set of <i>G</i> if each vertex has a neighbour in <i>S</i> or has at least two vertices in <i>S</i> at distance two from it. The minimum cardinality of such a set is the disjunctive total domination number. There are some graph modifications on the edge or vertex of a graph, one of which is subdividing an edge. The disjunctive total domination subdivision number of <i>G</i> is the minimum number of edges which must be subdivided (each edge in <i>G</i> can be subdivided exactly once) to increase the disjunctive total domination number. Firstly, we prove that the disjunctive total domination subdivision problem is NP-complete in bipartite graphs. We next establish some bounds on disjunctive total domination subdivision.</p>","PeriodicalId":50231,"journal":{"name":"Journal of Combinatorial Optimization","volume":"244 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2024-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142823187","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A study on $$k$$ - $$walk$$ generation algorithm to prevent the tottering in graph edit distance heuristic algorithms","authors":"SeongCheol Yoon, Daehee Seo, Su-Hyun Kim, Im-Yeong Lee","doi":"10.1007/s10878-024-01236-5","DOIUrl":"https://doi.org/10.1007/s10878-024-01236-5","url":null,"abstract":"<p>Graph edit distance is usually used for graph similarity checking due to its low information loss and flexibility advantages. However, graph edit distance can’t be used efficiently because it is an NP-Hard problem. Many graph edit distance heuristic algorithms have been proposed to solve this problem. However, some heuristic algorithms for generating <span>(walk)</span> generate unnecessary sequences because of the tottering, which leads to many problems. Because of this, various problems arise, like a decrease in approximation accuracy and an increase in execution time. In this paper, we propose an accurate and efficient graph edit distance heuristic algorithm that prevents tottering when generating <span>(walk)</span>. When generating <span>(walk)</span>, the traversed node‘s information is saved into the queue and then proceeds to traverse the next node. Then, it is possible to prevent the tottering by comparing an existing traversed node with an enqueued one. Through this, we propose a new <span>(walk)</span> generation algorithm that prevents generating unnecessary <span>(walk)</span> and applies it to existing algorithms to prevent the tottering.</p>","PeriodicalId":50231,"journal":{"name":"Journal of Combinatorial Optimization","volume":"27 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2024-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142788409","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}