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Optimal dispatching of electric vehicles based on optimized deep learning in IoT J. Comb. Optim. (IF 0.9) Pub Date : 2024-12-26 V. Agalya, M. Muthuvinayagam, R. Gandhi
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
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Lollipop and cubic weight functions for graph pebbling J. Comb. Optim. (IF 0.9) Pub Date : 2024-12-25 Marshall Yang, Carl Yerger, Runtian Zhou
Given a configuration of pebbles on the vertices of a graph G, a pebbling move removes two pebbles from a vertex and puts one pebble on an adjacent vertex. The pebbling number of a graph G 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 G through some sequence of pebbling moves. Through constructing
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Discrete circles: analytical definition and generation in the hexagonal grid J. Comb. Optim. (IF 0.9) Pub Date : 2024-12-19 Rita Zrour, Lidija Čomić, Eric Andres, Gaëlle Largeteau Skapin
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
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Optimal blocks for maximizing the transaction fee revenue of Bitcoin miners J. Comb. Optim. (IF 0.9) Pub Date : 2024-12-19 Mohsen Alambardar Meybodi, Amir Goharshady, Mohammad Reza Hooshmandasl, Ali Shakiba
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
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Sidon sets, thin sets, and the nonlinearity of vectorial Boolean functions J. Comb. Theory A (IF 0.9) Pub Date : 2024-12-19 Gábor P. Nagy
The vectorial nonlinearity of a vector-valued function is its distance from the set of affine functions. In 2017, Liu, Mesnager, and Chen conjectured a general upper bound for the vectorial linearity. Recently, Carlet established a lower bound in terms of differential uniformity. In this paper, we improve Carlet's lower bound. Our approach is based on the fact that the level sets of a vectorial Boolean
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Facial expression-based emotion recognition across diverse age groups: a multi-scale vision transformer with contrastive learning approach J. Comb. Optim. (IF 0.9) Pub Date : 2024-12-16 G. Balachandran, S. Ranjith, T. R. Chenthil, G. C. Jagan
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
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Online multiple one way non-preemptive time series search with interrelated prices J. Comb. Optim. (IF 0.9) Pub Date : 2024-12-16 Jinghan Zhao, Yongxi Cheng, Jan Eube, Haodong Liu
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
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Spectral influence in networks: an application to input-output analysis J. Comb. Optim. (IF 0.9) Pub Date : 2024-12-16 Nizar Riane
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
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Np-completeness and bounds for disjunctive total domination subdivision J. Comb. Optim. (IF 0.9) Pub Date : 2024-12-14 Canan Çiftçi, Aysun Aytaç
A subset \( S\subseteq V(G) \), where V(G) is the vertex set of a graph G, is a disjunctive total dominating set of G if each vertex has a neighbour in S or has at least two vertices in S 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.
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A study on $$k$$ - $$walk$$ generation algorithm to prevent the tottering in graph edit distance heuristic algorithms J. Comb. Optim. (IF 0.9) Pub Date : 2024-12-07 SeongCheol Yoon, Daehee Seo, Su-Hyun Kim, Im-Yeong Lee
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 \(walk\) generate unnecessary sequences because
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New bounds on the price of anarchy of selfish bin packing with partial punishment J. Comb. Optim. (IF 0.9) Pub Date : 2024-12-04 Xiaowei Li, Peihai Liu, Xiwen Lu
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 \(s_i\) moves to another bin, it has to pay the partial punishment of \(\alpha s_{i}\), where \(0<\alpha <1\). We prove that the price of anarchy
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Customer segmentation using flying fox optimization algorithm J. Comb. Optim. (IF 0.9) Pub Date : 2024-12-04 Konstantinos Zervoudakis, Stelios Tsafarakis
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
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Online scheduling on an unbounded parallel-batch machine to minimize the weighted makespan J. Comb. Optim. (IF 0.9) Pub Date : 2024-12-04 Han Zhang, Lingfa Lu, Jinjiang Yuan
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
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Greedy algorithms for stochastic monotone k-submodular maximization under full-bandit feedback J. Comb. Optim. (IF 0.9) Pub Date : 2024-12-04 Xin Sun, Tiande Guo, Congying Han, Hongyang Zhang
In this paper, we theoretically study the Combinatorial Multi-Armed Bandit problem with stochastic monotone k-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 k-submodular reward. The k-submodularity enriches the application scenarios of the problem we consider
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Approximation algorithms for the airport and railway problem J. Comb. Optim. (IF 0.9) Pub Date : 2024-12-04 Mohammad R. Salavatipour, Lijiangnan Tian
In this paper, we present approximation algorithms for the Airport and Railway problem (AR) on several classes of graphs. The \(\text{ AR }\) 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 Capacitated
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Incentive mechanism design for value-decreasing tasks in dynamic competitive edge computing networks J. Comb. Optim. (IF 0.9) Pub Date : 2024-12-03 Qie Li, Zichen Wang, Hongwei Du
With the rapid development of network architectures and application technologies, there is an increasing number of latency-sensitive tasks generated by user devices, necessitating real-time processing on edge servers. During peak periods, user devices compete for limited edge resources to execute their tasks, while different edge servers also compete for transaction opportunities. This article focus
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On joint short minimal zero-sum subsequences over finite abelian groups of rank two J. Comb. Theory A (IF 0.9) Pub Date : 2024-12-03 Yushuang Fan, Qinghai Zhong
Let (G,+,0) be a finite abelian group and let ηN(G) be the smallest integer ℓ such that every sequence over G∖{0} of length ℓ has two joint short minimal zero-sum subsequences. In 2013, Gao et al. obtained that ηN(Cn⊕Cn)=3n+1 for every n≥2 and solved the corresponding inverse problem for groups Cp⊕Cp, where p is a prime. In this paper, we determine the precise value of ηN(G) for all finite abelian
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Sequence reconstruction problem for deletion channels: A complete asymptotic solution J. Comb. Theory A (IF 0.9) Pub Date : 2024-11-27 Van Long Phuoc Pham, Keshav Goyal, Han Mao Kiah
Transmit a codeword ▪, that belongs to an (ℓ−1)-deletion-correcting code of length n, over a t-deletion channel for some 1≤ℓ≤t
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A classification of the flag-transitive 2-(v,k,2) designs J. Comb. Theory A (IF 0.9) Pub Date : 2024-11-26 Hongxue Liang, Alessandro Montinaro
In this paper, we provide a complete classification of 2-(v,k,2) designs admitting a flag-transitive automorphism group of affine type with the only exception of the semilinear 1-dimensional group. Alongside this analysis, we provide a construction of seven new families of such flag-transitive 2-designs, one of them infinite, and some of them involving remarkable objects such as t-spreads, translation
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Distributions of reciprocal sums of parts in integer partitions J. Comb. Theory A (IF 0.9) Pub Date : 2024-11-26 Byungchan Kim, Eunmi Kim
Let Dn be the set of partitions of n into distinct parts, and srp(λ) be the sum of reciprocals of the parts of the partition λ. We show that as n→∞,E[srp(λ):λ∈Dn]∼log(3n)4andVar[srp(λ):λ∈Dn]∼π224. Moreover, for Pn, the set of ordinary partitions of n, we show that as n→∞,E[srp(λ):λ∈Pn]∼πn6andVar[srp(λ):λ∈Pn]∼π215n. To prove these asymptotic formulas in a uniform manner, we derive a general asymptotic
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Non-empty pairwise cross-intersecting families J. Comb. Theory A (IF 0.9) Pub Date : 2024-11-26 Yang Huang, Yuejian Peng
Two families A and B are cross-intersecting if A∩B≠∅ for any A∈A and B∈B. We call t families A1,A2,…,At pairwise cross-intersecting families if Ai and Aj are cross-intersecting for 1≤i
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Enhanced deterministic approximation algorithm for non-monotone submodular maximization under knapsack constraint with linear query complexity J. Comb. Optim. (IF 0.9) Pub Date : 2024-11-22 Canh V. Pham
In this work, we consider the Submodular Maximization under Knapsack (\(\textsf{SMK}\)) constraint problem over the ground set of size n. The problem recently attracted a lot of attention due to its applications in various domains of combinatorial optimization, artificial intelligence, and machine learning. We improve the approximation factor of the fastest deterministic algorithm from \(6+\epsilon
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Dominance complexes, neighborhood complexes and combinatorial Alexander duals J. Comb. Theory A (IF 0.9) Pub Date : 2024-11-16 Takahiro Matsushita, Shun Wakatsuki
We show that the dominance complex D(G) of a graph G coincides with the combinatorial Alexander dual of the neighborhood complex N(G‾) of the complement of G. Using this, we obtain a relation between the chromatic number χ(G) of G and the homology group of D(G). We also obtain several known results related to dominance complexes from well-known facts of neighborhood complexes. After that, we suggest
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Different due-window assignment scheduling with deterioration effects J. Comb. Optim. (IF 0.9) Pub Date : 2024-11-13 Yurong Zhang, Xi Wang, Li-Han Zhang, Xue Jia, Ji-Bo Wang
This paper studies a due-window assignment scheduling problem with deterioration effects on a single-machine. Under different due-window assignment, i.e., the due-window of a job without any restriction, our goal is to make a decision on the optimal due-window and sequence of all jobs to minimize the weighted sum of earliness and tardiness, number of early and delayed, due-window starting time and
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An upper bound for neighbor-connectivity of graphs J. Comb. Optim. (IF 0.9) Pub Date : 2024-11-13 Hongliang Ma, Baoyindureng Wu
The neighbor-connectivity of a graph G, denoted by \(\kappa _{NB}(G)\), is the least number of vertices such that removing their closed neighborhoods from G results in a graph that is empty, complete, or disconnected. In the paper, we show that for any graph G of order n, \(\kappa _{NB}(G)\le \lceil \sqrt{2n}\ \rceil -2\). We pose a conjecture that \(\kappa _{NB}(G)\le \lceil \sqrt{n}\ \rceil -1\)
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A novel arctic fox survival strategy inspired optimization algorithm J. Comb. Optim. (IF 0.9) Pub Date : 2024-11-14 E. Subha, V. Jothi Prakash, S. Arul Antran Vijay
In the field of optimization algorithms, nature-inspired techniques have garnered attention for their adaptability and problem-solving prowess. This research introduces the Arctic Fox Algorithm (AFA), an innovative optimization technique inspired by the adaptive survival strategies of the Arctic fox, designed to excel in dynamic and complex optimization landscapes. Incorporating gradient flow dynamics
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Dynamic time window based full-view coverage maximization in CSNs J. Comb. Optim. (IF 0.9) Pub Date : 2024-11-13 Jingfang Su, Zeqing Li, Hongwei Du, Shengxin Liu
In order to maximize full-view coverage of moving targets in Camera Sensor Networks (CSNs), a novel method known as “group set cover” is presented in this research. Choosing the best camera angles and placements to accomplish full-view coverage of the moving targets is one of the main focuses of the research in CSNs. Discretize the target into multiple views of [0, 2\(\pi \)], use a set of views of
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On injective chromatic index of sparse graphs with maximum degree 5 J. Comb. Optim. (IF 0.9) Pub Date : 2024-11-07 Jian Lu, Zhen-Mu Hong, Zheng-Jiang Xia
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High-Dimensional Block Diagonal Covariance Structure Detection Using Singular Vectors J. Comput. Graph. Stat. (IF 1.4) Pub Date : 2024-11-05 Jan O. Bauer
The assumption of independent subvectors arises in many aspects of multivariate analysis. In most real-world applications, however, we lack prior knowledge about the number of subvectors and the sp...
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The vector space generated by permutations of a trade or a design J. Comb. Theory A (IF 0.9) Pub Date : 2024-11-06 E. Ghorbani, S. Kamali, G.B. Khosrovshahi
Motivated by a classical result of Graver and Jurkat (1973) and Graham, Li, and Li (1980) in combinatorial design theory, which states that the permutations of t-(v,k) minimal trades generate the vector space of all t-(v,k) trades, we investigate the vector space spanned by permutations of an arbitrary trade. We prove that this vector space possesses a decomposition as a direct sum of subspaces formed
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Upper bounds for the number of substructures in finite geometries from the container method J. Comb. Theory A (IF 0.9) Pub Date : 2024-11-06 Sam Mattheus, Geertrui Van de Voorde
We use techniques from algebraic and extremal combinatorics to derive upper bounds on the number of independent sets in several (hyper)graphs arising from finite geometry. In this way, we obtain asymptotically sharp upper bounds for partial ovoids and EKR-sets of flags in polar spaces, line spreads in PG(2r−1,q) and plane spreads in PG(5,q), and caps in PG(3,q). The latter result extends work due to
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The sum of root-leaf distance interdiction problem with cardinality constraint by upgrading edges on trees J. Comb. Optim. (IF 0.9) Pub Date : 2024-11-05 Xiao Li, Xiucui Guan, Qiao Zhang, Xinyi Yin, Panos M. Pardalos
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Non-submodular maximization with a decomposable objective function J. Comb. Optim. (IF 0.9) Pub Date : 2024-11-05 Cheng Lu, Wenguo Yang
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Counting cycles in planar triangulations J. Comb. Theory B (IF 1.2) Pub Date : 2024-11-05 On-Hei Solomon Lo, Carol T. Zamfirescu
We investigate the minimum number of cycles of specified lengths in planar n-vertex triangulations G. We prove that this number is Ω(n) for any cycle length at most 3+max{rad(G⁎),⌈(n−32)log32⌉}, where rad(G⁎) denotes the radius of the triangulation's dual, which is at least logarithmic but can be linear in the order of the triangulation. We also show that there exist planar hamiltonian n-vertex triangulations
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Some conjectures of Ballantine and Merca on truncated sums and the minimal excludant in congruences classes J. Comb. Theory A (IF 0.9) Pub Date : 2024-11-05 Olivia X.M. Yao
In 2012, Andrews and Merca proved a truncated theorem on Euler's pentagonal number theorem. Since then, a number of results on truncated theta series have been proved. In this paper, we find the connections between truncated sums of certain partition functions and the minimal excludant statistic which has been found to exhibit connections with a handful of objects such as Dyson's crank. We present
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Optimal Subsampling for Data Streams with Measurement Constrained Categorical Responses J. Comput. Graph. Stat. (IF 1.4) Pub Date : 2024-10-31 Jun Yu, Zhiqiang Ye, Mingyao Ai, Ping Ma
High-velocity, large-scale data streams have become pervasive. Frequently, the associated labels for such data prove costly to measure and are not always available upfront. Consequently, the analys...
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Minimum $$ s-t $$ hypercut in (s, t)-planar hypergraphs J. Comb. Optim. (IF 0.9) Pub Date : 2024-11-01 Abolfazl Hassanpour, Massoud Aman, Alireza Ebrahimi
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Maximizing diversity and persuasiveness of opinion articles in social networks J. Comb. Optim. (IF 0.9) Pub Date : 2024-11-01 Liman Du, Wenguo Yang, Suixiang Gao
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Multi-task Learning for Gaussian Graphical Regressions with High Dimensional Covariates J. Comput. Graph. Stat. (IF 1.4) Pub Date : 2024-10-31 Jingfei Zhang, Yi Li
Gaussian graphical regression is a powerful approach for regressing the precision matrix of a Gaussian graphical model on covariates, which permits the response variables and covariates to outnumbe...
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Latent Markov time-interaction processes J. Comput. Graph. Stat. (IF 1.4) Pub Date : 2024-10-31 Rosario Barone, Alessio Farcomeni, Maura Mezzetti
We present parametric and semiparametric latent Markov time-interaction processes, that are point processes where the occurrence of an event can increase or reduce the probability of future events....
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Multi-label Random Subspace Ensemble Classification1 J. Comput. Graph. Stat. (IF 1.4) Pub Date : 2024-10-28 Fan Bi, Jianan Zhu, Yang Feng
In this work, we develop a new ensemble learning framework, multi-label Random Subspace Ensemble (mRaSE), for multi-label classification. Given a base classifier (e.g., multinomial logistic regress...
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Heterogeneous functional regression for subgroup analysis J. Comput. Graph. Stat. (IF 1.4) Pub Date : 2024-10-28 Yeqing Zhou, Fei Jiang
With ever increasing number of features of modern datasets, data heterogeneity is gradually becoming the norm rather than the exception. Whereas classical regressions usually assume all the samples...
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On greedy approximation algorithm for the minimum resolving dominating set problem J. Comb. Optim. (IF 0.9) Pub Date : 2024-10-28 Hao Zhong
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Fashion game on graphs with more than two actions J. Comb. Optim. (IF 0.9) Pub Date : 2024-10-28 Qi Wang, Wensong Lin
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Qini Curves for Multi-Armed Treatment Rules J. Comput. Graph. Stat. (IF 1.4) Pub Date : 2024-10-24 Erik Sverdrup, Han Wu, Susan Athey, Stefan Wager
Qini curves have emerged as an attractive and popular approach for evaluating the benefit of data-driven targeting rules for treatment allocation. We propose a generalization of the Qini curve to m...
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Distortion corrected kernel density estimator on Riemannian manifolds J. Comput. Graph. Stat. (IF 1.4) Pub Date : 2024-10-24 Fan Cheng, Rob J Hyndman, Anastasios Panagiotelis
Manifold learning obtains a low-dimensional representation of an underlying Riemannian manifold supporting high-dimensional data. Kernel density estimates of the low-dimensional embedding with a fi...
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Algorithms for the bin packing problem with scenarios J. Comb. Optim. (IF 0.9) Pub Date : 2024-10-24 Yulle G. F. Borges, Vinícius L. de Lima, Flávio K. Miyazawa, Lehilton L. C. Pedrosa, Thiago A. de Queiroz, Rafael C. S. Schouery
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Efficient Sampling From the Watson Distribution in Arbitrary Dimensions J. Comput. Graph. Stat. (IF 1.4) Pub Date : 2024-10-23 Lukas Sablica, Kurt Hornik, Josef Leydold
In this paper, we present two efficient methods for sampling from the Watson distribution in arbitrary dimensions. The first method adapts the rejection sampling algorithm from Kent et al. (2018), ...
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Sampling random graphs with specified degree sequences J. Comput. Graph. Stat. (IF 1.4) Pub Date : 2024-10-24 Upasana Dutta, Bailey K. Fosdick, Aaron Clauset
The configuration model is a standard tool for uniformly generating random graphs with a specified degree sequence, and is often used as a null model to evaluate how much of an observed network’s s...
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A MILP model for the connected multidimensional maximum bisection problem J. Comb. Optim. (IF 0.9) Pub Date : 2024-10-22 Zoran Lj. Maksimović
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Reconstruction of hypermatrices from subhypermatrices J. Comb. Theory A (IF 0.9) Pub Date : 2024-10-22 Wenjie Zhong, Xiande Zhang
For a given n, what is the smallest number k such that every sequence of length n is determined by the multiset of all its k-subsequences? This is called the k-deck problem for sequence reconstruction, and has been generalized to the two-dimensional case – reconstruction of n×n-matrices from submatrices. Previous works show that the smallest k is at most O(n12) for sequences and at most O(n23) for
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Optimizing hospital bed allocation for coordinated medical efficiency and quality improvement J. Comb. Optim. (IF 0.9) Pub Date : 2024-10-21 Haiyue Yu, Ting Shen, Liwei Zhong
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The hamiltonian path graph is connected for simple s, t paths in rectangular grid graphs J. Comb. Optim. (IF 0.9) Pub Date : 2024-10-19 Rahnuma Islam Nishat, Venkatesh Srinivasan, Sue Whitesides
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Direct constructions of column-orthogonal strong orthogonal arrays J. Comb. Theory A (IF 0.9) Pub Date : 2024-10-18 Jingjun Bao, Lijun Ji, Juanjuan Xu
Strong orthogonal arrays have better space-filling properties than ordinary orthogonal arrays for computer experiments. Strong orthogonal arrays of strengths two plus, two star and three minus can improve the space-filling properties in low dimensions and column orthogonality plays a vital role in computer experiments. In this paper, we use difference matrices and generator matrices of linear codes
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AddiVortes: (Bayesian) Additive Voronoi Tessellations J. Comput. Graph. Stat. (IF 1.4) Pub Date : 2024-10-16 Adam. J. Stone, John Paul Gosling
The Additive Voronoi Tessellations (AddiVortes) model is a multivariate regression model that uses Voronoi tessellations to partition the covariate space in an additive ensemble model. Unlike other...
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Sample efficient nonparametric regression via low-rank regularization J. Comput. Graph. Stat. (IF 1.4) Pub Date : 2024-10-15 Jiakun Jiang, Jiahao Peng, Heng Lian
Nonparametric regression suffers from curse of dimensionality, requiring a relatively large sample size for accurate estimation beyond the univariate case. In this paper, we consider a simple metho...
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Scalable Clustering: Large Scale Unsupervised Learning of Gaussian Mixture Models with Outliers J. Comput. Graph. Stat. (IF 1.4) Pub Date : 2024-10-14 Yijia Zhou, Kyle A. Gallivan, Adrian Barbu
Clustering is a widely used technique with a long and rich history in a variety of areas. However, most existing algorithms do not scale well to large datasets, or are missing theoretical guarantee...
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Efficient heuristics to compute minimal and stable feedback arc sets J. Comb. Optim. (IF 0.9) Pub Date : 2024-10-15 Claudia Cavallaro, Vincenzo Cutello, Mario Pavone
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Trees with many leaves in tournaments J. Comb. Theory B (IF 1.2) Pub Date : 2024-10-15 Alistair Benford, Richard Montgomery
Sumner's universal tournament conjecture states that every (2n−2)-vertex tournament should contain a copy of every n-vertex oriented tree. If we know the number of leaves of an oriented tree, or its maximum degree, can we guarantee a copy of the tree with fewer vertices in the tournament? Due to work initiated by Häggkvist and Thomason (for number of leaves) and Kühn, Mycroft and Osthus (for maximum