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Efficient branch-and-bound algorithms for finding triangle-constrained 2-clubs J. Comb. Optim. (IF 0.9) Pub Date : 2024-09-21 Niels Grüttemeier, Philipp Heinrich Keßler, Christian Komusiewicz, Frank Sommer
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Wasserstein-Kaplan-Meier Survival Regression J. Comput. Graph. Stat. (IF 1.4) Pub Date : 2024-09-17 Yidong Zhou, Hans-Georg Müller
Survival analysis plays a pivotal role in medical research, offering valuable insights into the timing of events such as survival time. One common challenge in survival analysis is the necessity to...
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Efficient Large-scale Nonstationary Spatial Covariance Function Estimation Using Convolutional Neural Networks J. Comput. Graph. Stat. (IF 1.4) Pub Date : 2024-09-12 Pratik Nag, Yiping Hong, Sameh Abdulah, Ghulam A. Qadir, Marc G. Genton, Ying Sun
Spatial processes observed in various fields, such as climate and environmental science, often occur at large-scale and demonstrate spatial nonstationarity. However, fitting a Gaussian process with...
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Bayesian nowcasting with Laplacian-P-splines J. Comput. Graph. Stat. (IF 1.4) Pub Date : 2024-09-12 Bryan Sumalinab, Oswaldo Gressani, Niel Hens, Christel Faes
During an epidemic, the daily number of reported infected cases, deaths or hospitalizations is often lower than the actual number due to reporting delays. Nowcasting aims to estimate the cases that...
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Optimal Subsampling for Functional Quasi-Mode Regression with Big Data J. Comput. Graph. Stat. (IF 1.4) Pub Date : 2024-09-12 Tao Wang
We propose investigating optimal subsampling for functional regression with massive datasets based on the mode value, which is referred to as functional quasi-mode regression, to reduce data volume...
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Efficient convex PCA with applications to Wasserstein GPCA and ranked data J. Comput. Graph. Stat. (IF 1.4) Pub Date : 2024-09-12 Steven Campbell, Ting-Kam Leonard Wong
Convex PCA, which was introduced in Bigot et al. (2017), modifies Euclidean PCA by restricting the data and the principal components to lie in a given convex subset of a Hilbert space. This setting...
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The structure of quasi-transitive graphs avoiding a minor with applications to the domino problem J. Comb. Theory B (IF 1.2) Pub Date : 2024-09-02 Louis Esperet, Ugo Giocanti, Clément Legrand-Duchesne
An infinite graph is quasi-transitive if its vertex set has finitely many orbits under the action of its automorphism group. In this paper we obtain a structure theorem for locally finite quasi-transitive graphs avoiding a minor, which is reminiscent of the Robertson-Seymour Graph Minor Structure Theorem. We prove that every locally finite quasi-transitive graph avoiding a minor has a tree-decomposition
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The matroid of a graphing J. Comb. Theory B (IF 1.2) Pub Date : 2024-08-30 László Lovász
Graphings serve as limit objects for bounded-degree graphs. We define the “cycle matroid” of a graphing as a submodular setfunction, with values in , which generalizes (up to normalization) the cycle matroid of finite graphs. We prove that for a Benjamini–Schramm convergent sequence of graphs, the total rank, normalized by the number of nodes, converges to the total rank of the limit graphing.
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Minmax regret 1-sink location problems on dynamic flow path networks with parametric weights J. Comb. Optim. (IF 0.9) Pub Date : 2024-08-26 Tetsuya Fujie, Yuya Higashikawa, Naoki Katoh, Junichi Teruyama, Yuki Tokuni
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Co-factor analysis of citation networks J. Comput. Graph. Stat. (IF 1.4) Pub Date : 2024-08-27 Alex Hayes, Karl Rohe
One compelling use of citation networks is to characterize papers by their relationships to the surrounding literature. We propose a method to characterize papers by embedding them into two distinc...
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Optimal spread for spanning subgraphs of Dirac hypergraphs J. Comb. Theory B (IF 1.2) Pub Date : 2024-08-26 Tom Kelly, Alp Müyesser, Alexey Pokrovskiy
Let and be hypergraphs on vertices, and suppose has large enough minimum degree to necessarily contain a copy of as a subgraph. We give a general method to randomly embed into with good “spread”. More precisely, for a wide class of , we find a randomised embedding with the following property: for every , for any partial embedding of vertices of into , the probability that extends is at most . This
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Efficient estimation of the modified Gromov–Hausdorff distance between unweighted graphs J. Comb. Optim. (IF 0.9) Pub Date : 2024-08-23 Vladyslav Oles, Nathan Lemons, Alexander Panchenko
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Kruskal–Katona-type problems via the entropy method J. Comb. Theory B (IF 1.2) Pub Date : 2024-08-22 Ting-Wei Chao, Hung-Hsun Hans Yu
In this paper, we investigate several extremal combinatorics problems that ask for the maximum number of copies of a fixed subgraph given the number of edges. We call problems of this type Kruskal–Katona-type problems. Most of the problems that will be discussed in this paper are related to the joints problem. There are two main results in this paper. First, we prove that, in a 3-edge-colored graph
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Meta-heuristic-based hybrid deep learning model for vulnerability detection and prevention in software system J. Comb. Optim. (IF 0.9) Pub Date : 2024-08-20 Lijin Shaji, R. Suji Pramila
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Fast Bayesian Inference for Spatial Mean-Parameterized Conway–Maxwell–Poisson Models J. Comput. Graph. Stat. (IF 1.4) Pub Date : 2024-08-21 Bokgyeong Kang, John Hughes, Murali Haran
Count data with complex features arise in many disciplines, including ecology, agriculture, criminology, medicine, and public health. Zero inflation, spatial dependence, and non-equidispersion are ...
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The prize-collecting single machine scheduling with bounds and penalties J. Comb. Optim. (IF 0.9) Pub Date : 2024-08-16 Guojun Hu, Pengxiang Pan, Suding Liu, Ping Yang, Runtao Xie
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Extremal spectral radius of nonregular graphs with prescribed maximum degree J. Comb. Theory B (IF 1.2) Pub Date : 2024-08-12 Lele Liu
Let be a graph attaining the maximum spectral radius among all connected nonregular graphs of order with maximum degree Δ. Let be the spectral radius of . A nice conjecture due to Liu et al. (2007) asserts that for each fixed Δ. Concerning an important structural property of the extremal graphs , Liu and Li (2008) put forward another conjecture which states that has exactly one vertex of degree strictly
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Degrees of Freedom: Search Cost and Self-consistency J. Comput. Graph. Stat. (IF 1.4) Pub Date : 2024-08-08 Lijun Wang, Hongyu Zhao, Xiaodan Fan
Model degrees of freedom ( df ) is a fundamental concept in statistics because it quantifies the flexibility of a fitting procedure and is indispensable in model selection. To investigate the gap b...
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Beyond time-homogeneity for continuous-time multistate Markov models J. Comput. Graph. Stat. (IF 1.4) Pub Date : 2024-08-08 Emmett B. Kendall, Jonathan P. Williams, Gudmund H. Hermansen, Frederic Bois, Vo Hong Thanh
Multistate Markov models are a canonical parametric approach for data modeling of observed or latent stochastic processes supported on a finite state space. Continuous-time Markov processes describ...
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Scalable Estimation for Structured Additive Distributional Regression J. Comput. Graph. Stat. (IF 1.4) Pub Date : 2024-08-08 Nikolaus Umlauf, Johannes Seiler, Mattias Wetscher, Thorsten Simon, Stefan Lang, Nadja Klein
Obtaining probabilistic models is of high relevance in many recent applications. However, estimation of such distributional models with very large datasets remains a difficult task. In particular, ...
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Using rejection sampling probability of acceptance as a measure of independence J. Comput. Graph. Stat. (IF 1.4) Pub Date : 2024-08-06 Markku Kuismin
This paper proposes a new association statistic for determining whether random variables are statistically independent. The proposed association statistic can also be used to examine the strength o...
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Augmentation Samplers for Multinomial Probit Bayesian Additive Regression Trees J. Comput. Graph. Stat. (IF 1.4) Pub Date : 2024-08-05 Yizhen Xu, Joseph Hogan, Michael Daniels, Rami Kantor, Ann Mwangi
The multinomial probit (MNP) (Imai and van Dyk, 2005) framework is based on a multivariate Gaussian latent structure, allowing for natural extensions to multilevel modeling. Unlike multinomial logi...
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Blocked Gibbs sampler for hierarchical Dirichlet processes J. Comput. Graph. Stat. (IF 1.4) Pub Date : 2024-08-05 Snigdha Das, Yabo Niu, Yang Ni, Bani K. Mallick, Debdeep Pati
Posterior computation in hierarchical Dirichlet process (HDP) mixture models is an active area of research in nonparametric Bayes inference of grouped data. Existing literature almost exclusively f...
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Models for two-dimensional bin packing problems with customer order spread J. Comb. Optim. (IF 0.9) Pub Date : 2024-08-07 Mateus Martin, Horacio Hideki Yanasse, Maristela O. Santos, Reinaldo Morabito
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Approximating the probabilistic p-Center problem under pressure J. Comb. Optim. (IF 0.9) Pub Date : 2024-08-07 Marc Demange, Marcel A. Haddad, Cécile Murat
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On the complexity of minimum maximal acyclic matchings J. Comb. Optim. (IF 0.9) Pub Date : 2024-08-07 Juhi Chaudhary, Sounaka Mishra, B. S. Panda
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Polynomial algorithms for sparse spanners on subcubic graphs J. Comb. Optim. (IF 0.9) Pub Date : 2024-08-07 R. Gómez, F. K. Miyazawa, Y. Wakababayashi
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r-Euler-Mahonian statistics on permutations J. Comb. Theory A (IF 0.9) Pub Date : 2024-08-06 Shao-Hua Liu
Let and denote the permutation statistics -descent number and -excedance number, respectively. We prove that the pairs of permutation statistics and are equidistributed, where denotes the -major index defined by Don Rawlings and denotes the -Denert's statistic defined by Guo-Niu Han. When , this result reduces to the equidistribution of and , which was conjectured by Denert in 1990 and proved that
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Customer churn prediction using a novel meta-classifier: an investigation on transaction, Telecommunication and customer churn datasets J. Comb. Optim. (IF 0.9) Pub Date : 2024-08-03 Fatemeh Ehsani, Monireh Hosseini
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The automorphism group of a complementary prism J. Comb. Theory B (IF 1.2) Pub Date : 2024-08-02 Marko Orel
Given a finite simple graph Γ on vertices its complementary prism is the graph that is obtained from Γ and its complement by adding a perfect matching where each its edge connects two copies of the same vertex in Γ and . It generalizes the Petersen graph, which is obtained if Γ is the pentagon. The automorphism group of is described for an arbitrary graph Γ. In particular, it is shown that the ratio
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The q-Onsager algebra and the quantum torus J. Comb. Theory A (IF 0.9) Pub Date : 2024-08-02 Owen Goff
The -Onsager algebra, denoted , is defined by two generators and two relations called the -Dolan-Grady relations. Recently, Terwilliger introduced some elements of , said to be alternating. These elements are denoted
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An infinite family of hyperovals of Q+(5,q), q even J. Comb. Theory A (IF 0.9) Pub Date : 2024-08-01 Bart De Bruyn
We construct an infinite family of hyperovals on the Klein quadric , even. The construction makes use of ovoids of the symplectic generalized quadrangle that is associated with an elliptic quadric which arises as solid intersection with . We also solve the isomorphism problem: we determine necessary and sufficient conditions for two hyperovals arising from the construction to be isomorphic.
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First zagreb spectral radius of unicyclic graphs and trees J. Comb. Optim. (IF 0.9) Pub Date : 2024-07-30 Parikshit Das, Kinkar Chandra Das, Sourav Mondal, Anita Pal
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Algorithms for a two-machine no-wait flow shop scheduling problem with two competing agents J. Comb. Optim. (IF 0.9) Pub Date : 2024-07-30 Qi-Xia Yang, Long-Cheng Liu, Min Huang, Tian-Run Wang
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H-factors in graphs with small independence number J. Comb. Theory B (IF 1.2) Pub Date : 2024-07-31 Ming Chen, Jie Han, Guanghui Wang, Donglei Yang
Let be an -vertex graph. The vertex arboricity of is the least integer such that can be partitioned into parts and each part induces a forest in . We show that for sufficiently large , every -vertex graph with and contains an -factor, where or . The result can be viewed an analogue of the Alon–Yuster theorem in Ramsey–Turán theory, which generalizes the results of Balogh–Molla–Sharifzadeh and Knierim–Su
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An improved upper bound for the online graph exploration problem on unicyclic graphs J. Comb. Optim. (IF 0.9) Pub Date : 2024-07-29 Koji M. Kobayashi, Ying Li
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A weak box-perfect graph theorem J. Comb. Theory B (IF 1.2) Pub Date : 2024-07-30 Patrick Chervet, Roland Grappe
A graph is called if for every induced subgraph of , where is the clique number of and its chromatic number. The Weak Perfect Graph Theorem of Lovász states that a graph is perfect if and only if its complement is perfect. This does not hold for box-perfect graphs, which are the perfect graphs whose stable set polytope is box-totally dual integral.
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Risk-adjusted exponential gradient strategies for online portfolio selection J. Comb. Optim. (IF 0.9) Pub Date : 2024-07-28 Jin’an He, Fangping Peng, Xiuying Xie
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Maximizing stochastic set function under a matroid constraint from decomposition J. Comb. Optim. (IF 0.9) Pub Date : 2024-07-28 Shengminjie Chen, Donglei Du, Wenguo Yang, Suixiang Gao
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A proof of the Etzion-Silberstein conjecture for monotone and MDS-constructible Ferrers diagrams J. Comb. Theory A (IF 0.9) Pub Date : 2024-07-24 Alessandro Neri, Mima Stanojkovski
Ferrers diagram rank-metric codes were introduced by Etzion and Silberstein in 2009. In their work, they proposed a conjecture on the largest dimension of a space of matrices over a finite field whose nonzero elements are supported on a given Ferrers diagram and all have rank lower bounded by a fixed positive integer . Since stated, the Etzion-Silberstein conjecture has been verified in a number of
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Boundary rigidity of CAT(0) cube complexes J. Comb. Theory B (IF 1.2) Pub Date : 2024-07-22 Jérémie Chalopin, Victor Chepoi
In this note, we prove that finite CAT(0) cube complexes can be reconstructed from their boundary distances (computed in their 1-skeleta). This result was conjectured by Haslegrave, Scott, Tamitegama, and Tan (2023). The reconstruction of a finite cell complex from the boundary distances is the discrete version of the boundary rigidity problem, which is a classical problem from Riemannian geometry
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Fractional coloring with local demands and applications to degree-sequence bounds on the independence number J. Comb. Theory B (IF 1.2) Pub Date : 2024-07-22 Tom Kelly, Luke Postle
In a fractional coloring, vertices of a graph are assigned measurable subsets of the real line and adjacent vertices receive disjoint subsets; the fractional chromatic number of a graph is at most if it has a fractional coloring in which each vertex receives a subset of of measure at least . We introduce and develop the theory of “fractional colorings with local demands” wherein each vertex “demands”
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The Erdős-Gyárfás function [formula omitted] — So Gyárfás was right J. Comb. Theory B (IF 1.2) Pub Date : 2024-07-22 Patrick Bennett, Ryan Cushman, Andrzej Dudek, Paweł Prałat
A -coloring of is an edge-coloring of where every 4-clique spans at least five colors. We show that there exist -colorings of using colors. This settles a disagreement between Erdős and Gyárfás reported in their 1997 paper. Our construction uses a randomized process which we analyze using the so-called differential equation method to establish dynamic concentration. In particular, our coloring process
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An oriented discrepancy version of Dirac's theorem J. Comb. Theory B (IF 1.2) Pub Date : 2024-07-22 Andrea Freschi, Allan Lo
The study of graph discrepancy problems, initiated by Erdős in the 1960s, has received renewed attention in recent years. In general, given a 2-edge-coloured graph , one is interested in embedding a copy of a graph in with large discrepancy (i.e. the copy of contains significantly more than half of its edges in one colour).
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Bayesian Federated Learning with Hamiltonian Monte Carlo: Algorithm and Theory J. Comput. Graph. Stat. (IF 1.4) Pub Date : 2024-07-15 Jiajun Liang, Qian Zhang, Wei Deng, Qifan Song, Guang Lin
This work introduces a novel and efficient Bayesian federated learning algorithm, namely, the Federated Averaging stochastic Hamiltonian Monte Carlo (FA-HMC), for parameter estimation and uncertain...
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Using early rejection Markov chain Monte Carlo and Gaussian processes to accelerate ABC methods J. Comput. Graph. Stat. (IF 1.4) Pub Date : 2024-07-15 Xuefei Cao, Shijia Wang, Yongdao Zhou
Approximate Bayesian computation (ABC) is a class of Bayesian inference algorithms that targets problems with intractable or unavailable likelihood functions. It uses synthetic data drawn from the ...
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New string attractor-based complexities for infinite words J. Comb. Theory A (IF 0.9) Pub Date : 2024-07-18 Julien Cassaigne, France Gheeraert, Antonio Restivo, Giuseppe Romana, Marinella Sciortino, Manon Stipulanti
A is a set of positions in a word such that each distinct factor has an occurrence crossing a position from the set. This definition comes from the data compression field, where the size of a smallest string attractor represents a lower bound for the output size of a large family of string compressors exploiting repetitions in words, including BWT-based and LZ-based compressors. For finite words, the
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Embedding and the first Laplace eigenvalue of a finite graph J. Comb. Optim. (IF 0.9) Pub Date : 2024-07-16 Takumi Gomyou, Toshimasa Kobayashi, Takefumi Kondo, Shin Nayatani
Göring–Helmberg–Wappler introduced optimization problems regarding embeddings of a graph into a Euclidean space and the first nonzero eigenvalue of the Laplacian of a graph, which are dual to each other in the framework of semidefinite programming. In this paper, we introduce a new graph-embedding optimization problem, and discuss its relation to Göring–Helmberg–Wappler’s problems. We also identify
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Improved bounds for the zeros of the chromatic polynomial via Whitney's Broken Circuit Theorem J. Comb. Theory B (IF 1.2) Pub Date : 2024-07-16 Matthew Jenssen, Viresh Patel, Guus Regts
We prove that for any graph of maximum degree at most Δ, the zeros of its chromatic polynomial (in ) lie inside the disc of radius 5.94Δ centered at 0. This improves on the previously best known bound of approximately 6.91Δ.
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Linkages and removable paths avoiding vertices J. Comb. Theory B (IF 1.2) Pub Date : 2024-07-15 Xiying Du, Yanjia Li, Shijie Xie, Xingxing Yu
A graph is -linked if, for any distinct vertices in , there exist disjoint connected subgraphs of such that and . A fundamental result in structural graph theory is the characterization of -linked graphs. It appears to be difficult to characterize -linked graphs for . In this paper, we provide a partial characterization of -linked graphs. This implies that every -connected graphs is -linked and for
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Spectral arbitrariness for trees fails spectacularly J. Comb. Theory B (IF 1.2) Pub Date : 2024-07-14 Shaun M. Fallat, H. Tracy Hall, Rupert H. Levene, Seth A. Meyer, Shahla Nasserasr, Polona Oblak, Helena Šmigoc
Given a graph , consider the family of real symmetric matrices with the property that the pattern of their nonzero off-diagonal entries corresponds to the edges of . For the past 30 years a central problem has been to determine which spectra are realizable in this matrix class. Using combinatorial methods, we identify a family of graphs and multiplicity lists whose realizable spectra are highly restricted
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Computational methods for fast Bayesian model assessment via calibrated posterior p-values J. Comput. Graph. Stat. (IF 1.4) Pub Date : 2024-07-11 Sally Paganin, Perry de Valpine
Posterior predictive p-values (ppps) have become popular tools for Bayesian model assessment, being general-purpose and easy to use. However, interpretation can be difficult because their distribut...
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Stochastic Block Smooth Graphon Model J. Comput. Graph. Stat. (IF 1.4) Pub Date : 2024-07-08 Benjamin Sischka, Göran Kauermann
In this paper, we propose combining the stochastic blockmodel and the smooth graphon model, two of the most prominent modeling approaches in statistical network analysis. Stochastic blockmodels are...
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A Tidy Framework and Infrastructure to Systematically Assemble Spatio-temporal Indexes from Multivariate Data J. Comput. Graph. Stat. (IF 1.4) Pub Date : 2024-07-08 H. Sherry Zhang, Dianne Cook, Ursula Laa, Nicolas Langrené, Patricia Menéndez
Indexes are useful for summarizing multivariate information into single metrics for monitoring, communicating, and decision-making. While most work has focused on defining new indexes for specific ...
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Continuous-time multivariate analysis J. Comput. Graph. Stat. (IF 1.4) Pub Date : 2024-07-08 Biplab Paul, Philip T. Reiss, Erjia Cui, Noemi Foà
The starting point for much of multivariate analysis (MVA) is an n × p data matrix whose n rows represent observations and whose p columns represent variables. Some multivariate data sets, however,...
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Fast Computer Model Calibration using Annealed and Transformed Variational Inference J. Comput. Graph. Stat. (IF 1.4) Pub Date : 2024-07-08 Dongkyu Derek Cho, Won Chang, Jaewoo Park
Computer models play a crucial role in numerous scientific and engineering domains. To ensure the accuracy of simulations, it is essential to properly calibrate the input parameters of these models...
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Cluster braid groups of Coxeter-Dynkin diagrams J. Comb. Theory A (IF 0.9) Pub Date : 2024-07-10 Zhe Han, Ping He, Yu Qiu
Cluster exchange groupoids are introduced by King-Qiu as an enhancement of cluster exchange graphs to study stability conditions and quadratic differentials. In this paper, we introduce the cluster exchange groupoid for any finite Coxeter-Dynkin diagram Δ and show that its fundamental group is isomorphic to the corresponding braid group associated with Δ.
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Functional Time Series Analysis and Visualization Based on Records J. Comput. Graph. Stat. (IF 1.4) Pub Date : 2024-07-08 Israel Martínez-Hernández, Marc G. Genton
In many phenomena, data are collected on a large scale and at different frequencies. In this context, functional data analysis (FDA) has become an important statistical methodology for analyzing an...
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Restricted bargraphs and unimodal compositions J. Comb. Theory A (IF 0.9) Pub Date : 2024-07-05 Rigoberto Flórez, José L. Ramírez, Diego Villamizar
In this paper, we present a study on , which are polygons created by connecting unit squares along their edges. Specifically, we focus on a related concept called a , which is a path on a lattice in traced along the boundaries of a column convex polyomino where the lower edge is on the -axis. To explore new variations of bargraphs, we introduce the notion of , which incorporate an additional restriction
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A hybrid grey wolf optimizer for engineering design problems J. Comb. Optim. (IF 0.9) Pub Date : 2024-07-03 Shuilin Chen, Jianguo Zheng