Journal of Combinatorial Optimization最新文献

{"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}

{"title":"New bounds on the price of anarchy of selfish bin packing with partial punishment","authors":"Xiaowei Li, Peihai Liu, Xiwen Lu","doi":"10.1007/s10878-024-01239-2","DOIUrl":"https://doi.org/10.1007/s10878-024-01239-2","url":null,"abstract":"<p>The selfish bin packing with partial punishment is studied in this paper. In this problem, the utility of an item is defined as the load of the bin it is in. Each item plays the role of a selfish agent and wants to maximize its own utility. If an item with size <span>(s_i)</span> moves to another bin, it has to pay the partial punishment of <span>(alpha s_{i})</span>, where <span>(0&lt;alpha &lt;1)</span>. We prove that the price of anarchy (<i>PoA</i>) of this game is at least 1.6424 for any <span>(alpha in (0,1))</span>. In particular, the <i>PoA</i> of this game is at least <span>(5/3 approx 1.6667)</span> for any <span>(alpha in (frac{2}{5},1))</span>. Furthermore, we obtain a new upper bound of <span>(h(alpha ) le 31/18 approx 1.7222)</span> on the <i>PoA</i>.</p>","PeriodicalId":50231,"journal":{"name":"Journal of Combinatorial Optimization","volume":"66 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2024-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142776402","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":"Greedy algorithms for stochastic monotone k-submodular maximization under full-bandit feedback","authors":"Xin Sun, Tiande Guo, Congying Han, Hongyang Zhang","doi":"10.1007/s10878-024-01240-9","DOIUrl":"https://doi.org/10.1007/s10878-024-01240-9","url":null,"abstract":"<p>In this paper, we theoretically study the Combinatorial Multi-Armed Bandit problem with stochastic monotone <i>k</i>-submodular reward function under full-bandit feedback. In this setting, the decision-maker is allowed to select a super arm composed of multiple base arms in each round and then receives its <i>k</i>-submodular reward. The <i>k</i>-submodularity enriches the application scenarios of the problem we consider in contexts characterized by diverse options. We present two simple greedy algorithms for two budget constraints (total size and individual size) and provide the theoretical analysis for upper bound of the regret value. For the total size budget, the proposed algorithm achieves a <span>(frac{1}{2})</span>-regret upper bound by <span>(tilde{mathcal {O}}left( T^frac{2}{3}(kn)^{frac{1}{3}}Bright) )</span> where <i>T</i> is the time horizon, <i>n</i> is the number of base arms and <i>B</i> denotes the budget. For the individual size budget, the proposed algorithm achieves a <span>(frac{1}{3})</span>-regret with the same upper bound. Moreover, we conduct numerical experiments on these two algorithms to empirically demonstrate the effectiveness.</p>","PeriodicalId":50231,"journal":{"name":"Journal of Combinatorial Optimization","volume":"37 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2024-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142776406","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 scheduling on an unbounded parallel-batch machine to minimize the weighted makespan","authors":"Han Zhang, Lingfa Lu, Jinjiang Yuan","doi":"10.1007/s10878-024-01242-7","DOIUrl":"https://doi.org/10.1007/s10878-024-01242-7","url":null,"abstract":"<p>In this paper we study the online over-time scheduling on an unbounded parallel-batch machine to minimize the weighted makespan. First, we show that the general problem has a low bound 2 and then design a 4-competitive online algorithm. Furthermore, we consider a special case in which the jobs have agreeable processing times and weights. When all jobs have the same weights (the task is to minimize the makespan), an online algorithm with the best possible competitive ratio <span>(frac{sqrt{5}+1}{2}approx 1.618)</span> has been established in the literature. We show that, after a slightly modification, this known online algorithm also has the best possible competitive ratio <span>(frac{sqrt{5}+1}{2}approx 1.618)</span> for our problem. Finally, we introduce limited restarts into the above special case and present an online algorithm with a better competitive ratio <span>(frac{11}{7}approx 1.571)</span>.</p>","PeriodicalId":50231,"journal":{"name":"Journal of Combinatorial Optimization","volume":"41 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2024-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142776405","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":"Approximation algorithms for the airport and railway problem","authors":"Mohammad R. Salavatipour, Lijiangnan Tian","doi":"10.1007/s10878-024-01237-4","DOIUrl":"https://doi.org/10.1007/s10878-024-01237-4","url":null,"abstract":"&lt;p&gt;In this paper, we present approximation algorithms for the &lt;span&gt;Airport and Railway&lt;/span&gt; problem (AR) on several classes of graphs. The &lt;span&gt;(text{ AR })&lt;/span&gt; problem, introduced as reported by Adamaszek et al. (in: Ollinger, Vollmer (eds) 33rd symposium on theoretical aspects of computer science (STACS 2016). Leibniz international proceedings in informatics (LIPIcs), Dagstuhl, 2016), is a combination of the &lt;span&gt;Capacitated Facility Location&lt;/span&gt; problem (CFL) and the &lt;span&gt;Network Design Problem&lt;/span&gt; (NDP). An &lt;span&gt;(text{ AR })&lt;/span&gt; instance consists of a set of points (cities) &lt;i&gt;V&lt;/i&gt; in a metric &lt;i&gt;d&lt;/i&gt;(., .), each of which is associated with a non-negative cost &lt;span&gt;(f_v)&lt;/span&gt; and a number &lt;i&gt;k&lt;/i&gt;, which represent respectively the cost of establishing an airport (facility) in the corresponding point, and the universal airport capacity. A feasible solution is a network of airports and railways providing services to all cities without violating any capacity, where railways are edges connecting pairs of points, with their costs equivalent to the distance between the respective points. The objective is to find such a network with the least cost. In other words, find a forest, each component having at most &lt;i&gt;k&lt;/i&gt; points and one open facility, minimizing the total cost of edges and airport opening costs. As reported by Adamaszek et al. (in: Ollinger, Vollmer (eds) 33rd symposium on theoretical aspects of computer science (STACS 2016). Leibniz international proceedings in informatics (LIPIcs), Dagstuhl, 2016) presented a PTAS for &lt;span&gt;(text{ AR })&lt;/span&gt; in the two-dimensional Euclidean metric &lt;span&gt;(mathbb {R}^2)&lt;/span&gt; with a uniform opening cost. In subsequent work (as reported by Adamaszek et al. (in: Niedermeier, Vallée (eds) 35th symposium on theoretical aspects of computer science (STACS 2018). Leibniz international proceedings in informatics (LIPIcs), Dagstuhl, 2018).) presented a bicriteria &lt;span&gt;(frac{4}{3}left( 2+frac{1}{alpha }right) )&lt;/span&gt;-approximation algorithm for &lt;span&gt;(text{ AR })&lt;/span&gt; with non-uniform opening costs but violating the airport capacity by a factor of &lt;span&gt;(1+alpha )&lt;/span&gt;, i.e. &lt;span&gt;((1+alpha )k)&lt;/span&gt; capacity where &lt;span&gt;(0&lt;alpha le 1)&lt;/span&gt;, a &lt;span&gt;(left( 2+frac{k}{k-1}+varepsilon right) )&lt;/span&gt;-approximation algorithm and a bicriteria Quasi-Polynomial Time Approximation Scheme (QPTAS) for the same problem in the Euclidean plane &lt;span&gt;(mathbb {R}^2)&lt;/span&gt;. In this work, we give a 2-approximation for &lt;span&gt;(text{ AR })&lt;/span&gt; with a uniform opening cost for general metrics and an &lt;span&gt;(O(log n))&lt;/span&gt;-approximation for non-uniform opening costs. We also give a QPTAS for &lt;span&gt;(text{ AR })&lt;/span&gt; with a uniform opening cost in graphs of bounded treewidth and a QPTAS for a slightly relaxed version in the non-uniform setting. The latter implies &lt;i&gt;O&lt;/i&gt;(1)-approximation on graphs of bounded doubling dimensions, graphs of bounded highway dimensions and planar graphs in quasi-","PeriodicalId":50231,"journal":{"name":"Journal of Combinatorial Optimization","volume":"77 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2024-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142776407","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":"Customer segmentation using flying fox optimization algorithm","authors":"Konstantinos Zervoudakis, Stelios Tsafarakis","doi":"10.1007/s10878-024-01243-6","DOIUrl":"https://doi.org/10.1007/s10878-024-01243-6","url":null,"abstract":"<p>Customer segmentation, a critical strategy in marketing, involves grouping consumers based on shared characteristics like age, income, and geographical location, enabling firms to effectively establish different strategies depending on the target group of customers. Clustering is a widely utilized data analysis technique that facilitates the identification of diverse groups, each distinguished by their unique set of characteristics. Traditional clustering techniques often lack in handling the complexity of consumer data. This paper introduces a novel approach employing the Flying Fox Optimization algorithm, inspired by the survival strategies of flying foxes, to determine customer segments. Applied to two different datasets, this method demonstrates superior capability in identifying distinct customer groups, thereby facilitating the development of targeted marketing strategies. Our comparative analysis with existing state-of-the-art as well as recently developed clustering methods reveals that the proposed method outperforms them in terms of segmentation capabilities. This research not only presents an innovative clustering technique in market segmentation but also showcases the potential of computational intelligence in improving marketing strategies, enhancing their alignment with each customer’s needs.</p>","PeriodicalId":50231,"journal":{"name":"Journal of Combinatorial Optimization","volume":"78 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2024-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142776404","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}