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32nd Annual European Symposium on Algorithms, ESA 2024

作者： Wu, Pu Gu, Huanyu Jiang, Huiqin Shao, Zehui Xu, Jin School of Computer Science Peking University Beijing China Institute of Computing Science and Technology Guangzhou University China Key Laboratory of High Confidence Software Technologies Peking University Ministry of Education Beijing China

ISBN: (纸本)9783959773386

We explore the 4-coloring problem, a fundamental combinatorial NP-hard problem. Given a graph G, the 4-coloring problem asks whether there exists a function f from the vertex set of G to {1, 2, 3, 4} such that f(u) ≠ f(v) for each edge uv of G. Such function f is referred to as a 4-coloring of G. The fastest known algorithm for the 4-coloring problem, introduced by Fomin, Gaspers, and Saurabh (COCOON 2007), exhibits a time complexity of O(1.7272n) and exponential space. In this paper, we propose an enhanced algorithm for the 4-coloring problem with a time complexity of O(1.7159n) and polynomial space. Our algorithm is deterministic and built upon a novel method. Specifically, inspired by previous algorithmic approaches for the 4-coloring problem, such as the aforementioned O(1.7272n) time algorithm, we consider the instance (G, I, S), where G is a graph and I, S are subsets of its vertex set representing vertices colored with 1 and vertices unable to be colored with 1, respectively. For a given instance (G, I, S), we aim to determine the existence of a 4-coloring f of G such that f(v) = 1 for v ∈ I and f(v) ≠ 1 for v ∈ S. Our key innovation lies in recognizing that, leveraging certain combinatorial properties, the instance (G, I, S) can be efficiently solved when G − I − S is a union of K3's and K4's (where K3 and K4 denote complete graphs with 3 and 4 vertices, respectively). The ability to efficiently solve instances (G, I, S), where G − I − S is comprised solely of K3's and K4's, enables us to devise a branching algorithm capable of efficiently addressing instances (G, I, S), where G − I − S is not a union of K3's and K4's (the other case). Based on this innovative method, we derive our final enhanced algorithm. © Pu Wu, Huanyu Gu, Huiqin Jiang, Zehui Shao, and Jin Xu;licensed under Creative Commons License CC-BY 4.0.

关键词： Graph algorithms

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A New Method for Evaluating Core Developers In Open Source Software 13

A New Method for Evaluating Core Developers In Open Source S...

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13th IEEE International Conference on Software Engineering and Service Science, ICSESS 2022

作者： Song, Yulin Wang, Tao Shen, Yang Chang, Junsheng National University of Defense Technology National Laboratory for Parallel and Distributed Processing Hunan Province Changsha China National University of Defense Technology Institute for Quantum Information State Key Laboratory of High Performance Computing Hunan Province Changsha China

ISBN: (数字)9781665410328

ISBN: (纸本)9781665410311

The high-quality development of Open Source Software(OSS) benefits from the contributions of developers. An important research question is how to truly assess the extent of contribution of all developers in open source software and effectively identify the core developers to avoid their loss. In this paper, we use the undirected weighted network model to build a Developer Collaboration Network(DCN) based on developers and their contributions to the GitHub community's open source software Rails, analyse the characteristics of developer partnerships through the Developer Collaboration Network, and propose a Developer Personal Impact Factor(DPIF) to evaluate the importance of developer, select the top 10 core developers in Rails, focus on their participation in the open source software process, and predicting the changes of their contributions. The experimental results show that core developers with extensive partnerships are more likely to associate with developers with fewer partnerships. The average degree of developer contribution does not increase with more developers. Developer partnerships are characterized by close localization and loose overall relationships. The Developer Personal Impact Factor identifies the core developers in open source software well. The Developer Personal Impact Factor gives a ranking in which the core team members rank in the top 1.17% on average. © 2022 IEEE.

关键词： Open source software

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Multi-Restricted Point Cloud Adversarial Attack based on Sensitivity Maps

Multi-Restricted Point Cloud Adversarial Attack based on Sen...

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Artificial Intelligence, Networking and Information technology (AINIT), International Seminar on

作者： Geng Chen Teng Li State Key Laboratory of High-Performance Computing National University of Defense Technology Changsha China The College of Advanced Interdisciplinary Studies National University of Defense Technology Changsha China

ISBN: (数字)9798350385557

ISBN: (纸本)9798350385564

The point cloud classification networks have been widely applied in 3D Reconstruction and Remote Sensing. The backbone of these networks is often implemented based on Deep Neural Networks (DNNs). Currently, a series of studies confirm that DNNs are vulnerable and susceptible to interference from adversarial samples. The existing strategies for attack and defense are primarily focused on the image domain. Due to the unordered and unstructured nature of point clouds, there has been limited research on attack algorithms for point clouds. Current black-box transferable attack algorithms face a challenge in balancing adversary and imperceptibility. They often lead to either a low Attack Success Rate (ASR) or the emergence of significant outlier points, which can be removed by Statistical Outlier Removal (SOR) methods easily. Inspired by principles from attack algorithm in image domain, this article introduces a novel approach. After extensive evaluation on several mainstream recognition models (such as $\text{PointNet}++$ and DGCNN), we have demonstrated that our black-box transferable attack method achieves state-of-the-art performance. To the best of our knowledge, we are the first to propose a point cloud black box transferable attack algorithm based on improved MI-FGSM.

关键词： Point cloud compression Seminars Adaptation models Solid modeling Three-dimensional displays Sensitivity Closed box

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Abnormal thermal conductivity enhancement in covalently bonded bilayer borophene allotrope

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Nano Research 2022年第4期15卷 3818-3824页

作者： Yan Yin Yanxiao Hu Shichang Li Guangqian Ding Shifa Wang Dengfeng Li Gang Zhang School of Science Chongqing University of Posts and TelecommunicationsChongqing 400065China Chongqing Key Laboratory of Geological Environment Monitoring and Disaster Early-warning in Three Gorges Reservoir Area Chongqing Three Gorges UniversityChongqing 404000China Institute of High Performance Computing A*STARSingapore 138632Singapore

Thermal conductivity of two-dimensional(2D)materials has gained prominence due to the attractive applications in thermal management and thermoelectric *** this work,we present a new member of bilayer 2D boron allotropes,denoted as bilayerβ12 borophene,and study the thermal transport properties by solving phonon Boltzmann transport equation based on density functional *** on quantitative chemical bonding analysis,we identify large degrees of covalent bonding of the interlayer *** comparison to its monolayer counterpart,the bilayer exhibits much higher in-plane thermal conductivity despite the lower phonon group velocity and buckling structure,inferring a new physical *** thermal conductivity(κ)of bilayerβ_(12)borophene at 300 K is 140.5(86.3)W·m^(-1)·K^(-1)along armchair(zigzag)direction,andκ_(armchair)is about 52.7%higher than that of monolayerβ12 *** abnormal enhancement is attributed to the suppressed phonon scattering possibility and elongation of phonon *** interesting,after forming bilayerβ12 borophene through interlayer covalent bonding,the dominated phonon branch to thermal conductivity changes to transverse acoustic phonons from out-of-plane flexural acoustic(ZA)phonons in the monolayer *** study elucidates the rich thermal transport characteristics in bilayer covalently bonded 2D materials,and injects fresh insights into the phonon engineering of 2D borophene relevant for emergent thermal management applications.

关键词： theory conductivity phonon

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Associations Between Specific Diets, Dietary Diversity, and Cognitive Frailty in Older Adults — China, 2002–2018

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China CDC weekly 2023年第39期5卷 872-876,I0005,I0006页

作者： Qingmei Huang Wenfang Zhong Ziting Chen Zhihao Li Peidong Zhang Yujie Zhang Peiliang Chen Qi Fu Weiqi Song Yuebin Lyu Xiaoming Shi Chen Mao Department of Epidemiology School of Public HealthSouthern Medical UniversityGuangzhou CityGuangdong ProvinceChina Southern Medical University High Performance Computing Center Guangzhou CityGuangdong ProvinceChina China CDC Key Laboratory of Environment and Population Health National Institute of Environmental HealthChinese Center for Disease Control and PreventionBeijingChina.

Summary What is already known about this topic?The relationship between specific dietary patterns and dietary diversity with cognitive frailty continues to be a subject of *** is added by this report?This research revealed that regular consumption of fruit,meat,bean products,garlic,and tea was connected to a decreased risk of cognitive *** to participants with dietary diversity score(DDS)≤6 points,those with DDS of 9–10,11–12,and≥12 had a lower risk of cognitive frailty.

关键词： DDS ambiguity continue

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Dynamic Task Allocation for Heterogeneous Multi-Robot System under Communication Constraints

Dynamic Task Allocation for Heterogeneous Multi-Robot System...

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IEEE Information technology, Networking, Electronic and Automation Control Conference

作者： Jun Li Zhongxuan Cai Minglong Li Wanrong Huang Yongjun Zhang Institute for Quantum Information & State Key Laboratory of High Performance Computing College of Computer National University of Defense Technology China

Multi-robot system has important application potential in disaster rescue and other dangerous scenarios, in which task allocation is the basis for multi-robot cooperation to complete tasks. Due to the limited ability of individual robots, many complex scenarios requires coordination of different types of robot, e.g. robots for search, communication, rescue and so on. At the same time, communication is often limited in a wide range of scenarios. This brings two challenges in the realistic environment: heterogeneous multi-robot cooperation problem and communication constraint problem. This paper proposes a task allocation method based on hierarchical auction and dynamic grouping. By introducing a dynamic grouping algorithm to the general allocation procedure, we simultaneously optimize the number of robots in each group and the communication distance between robots. Then the communication loss rate can be reduced to improve task execution efficiency. Simulations of a communication constrained search and rescue scenario are conducted to verify the proposed algorithm, which are compared with the vanilla auction algorithm and a hierarchical approach on static grouping. The results show that our method surpasses the baseline on both task achievement and communication performance.

关键词： Uncertainty Automation Adaptive systems Robot kinematics Heuristic algorithms Dynamic scheduling Resource management

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Hopf and double Hopf bifurcations in a delayed lateral vibration model of footbridges induced by pedestrians

arXiv

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arXiv 2025年

作者： Li, Xuemei Liu, Yechi Key Laboratory of High Performance Computing and Stochastic Information Processing Department of Mathematics Hunan Normal University Hunan Changsha410081 China

In this paper, we investigate the dynamical behaviors of a delayed lateral vibration model of footbridges proposed based on the facts that pedestrians will reduce their walking speed or stop walking when the response of the footbridge becomes sufficiently large, and that the bridge velocity can not be changed at once when the pedestrians begin to walk on the bridge. By analyzing the distribution of roots of the associated characteristic equation, we find that there are only two types of bifurcations in this model: Hopf bifurcation and double Hopf bifurcation, and give the condition on the stability of the trivial solution. By using the center manifold theorem and bifurcation theory of delayed differential equations, we obtain the dynamical behavior in these bifurcations, specially including the stability of periodic solutions and invariant tori bifurcating from the trivial solution in these bifurcations. Finally, we prove that this model exhibits quasi-periodic vibrations by KAM theorems, besides periodic vibrations. © 2025, CC BY-NC-ND.

关键词： Hopf bifurcation

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Energy-Constrained Task Scheduling in Heterogeneous Distributed Systems 26

Energy-Constrained Task Scheduling in Heterogeneous Distribu...

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26th International Conference on Computer Supported Cooperative Work in Design, CSCWD 2023

作者： Chen, Chen Zhu, Jie Huang, Haiping Gao, Yingmeng Nanjing University of Posts & Telecommunications Nanjing210003 China Institute of Computing Technology Academy of Sciences State Key Laboratory Chinese of Computer Architecture Beijing100864 China Jiangsu High Technology Research Key Laboratory for Wireless Sensor Networks Nanjing210003 China

ISBN: (纸本)9798350331684

The resource-constrained task scheduling problem has been one of the popular research topics in cloud computing systems. By employing the dynamic voltage and frequency scaling (DVFS) techniques, the task scheduling can be further constrained by energy consumption. The paper investigates the DAG task scheduling considering both the resource and energy constraints in heterogeneous distributed systems. The objective is to minimize the scheduling length. An energy-constrained task scheduling framework is employed, where tasks are initially scheduled according to their upward rank values. Then two heuristics are proposed to improve the initial solution, namely, the simulated annealing local search method and the frequency adjustment method. Experiments are conducted by testing a large number of instances with multiple parameter settings, and the results show that the proposed algorithms are effective and efficient. © 2023 IEEE.

关键词： Energy utilization

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Accumulative Time Based Ranking Method to Reputation Evaluation in Information Networks

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Journal of Computer Science & technology 2022年第4期37卷 960-974页

作者： Hao Liao Qi-Xin Liu Ze-Cheng Huang Ke-Zhong Lu Chi Ho Yeung Yi-Cheng Zhang National Engineering Laboratory on Big Data System Computing Technology College of Computer Science and SoftwareEngineeringShenzhen UniversityShenzhen 518060China Guangdong Province Key Laboratory of Popular High Performance Computers Shenzhen UniversityShenzhen 518060China Guangdong Province Engineering Center of China-Made High Performance Data Computing System College of ComputerScience and Software EngineeringShenzhen UniversityShenzhen 518060China Institute of Big Data Intelligent Management and Decision Shenzhen UniversityShenzhen 518060China Department of Science and Environmental Studies The Education University of Hong KongHong Kong 999077China Department of Physics University of FribourgFribourg 1700Switzerland

Due to over-abundant information on the Web, information filtering becomes a key task for online users to obtain relevant suggestions and how to extract the most related item is always a key topic for researchers in various fields. In this paper, we adopt tools used to analyze complex networks to evaluate user reputation and item quality. In our proposed Accumulative Time Based Ranking (ATR) algorithm, we take into account the growth record of the network to identify the evolution of the reputation of users and the quality of items, by incorporating two behavior weighting factors which can capture the hidden facts on reputation and quality dynamics for each user and item respectively. Our proposed ATR algorithm mainly combines the iterative approach to rank user reputation and item quality with temporal dependence compared with other reputation evaluation methods. We show that our algorithm outperforms other benchmark ranking algorithms in terms of precision and robustness on empirical datasets from various online retailers and the citation datasets among research publications. Therefore, our proposed method has the capability to effectively evaluate user reputation and item quality.

关键词： temporal network behavior dynamics reputation evaluation ranking algorithm

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LprViT:An Efficient ViT for LiDAR-Based Place Recognition Using Range Image

LprViT:An Efficient ViT for LiDAR-Based Place Recognition Us...

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Communication, Image and Signal Processing (CCISP), International Conference on

作者： Rui He Yunzhe Xiao Shaowu Yang Quantum Information & State Key Laboratory of High Performance Computing College of Computer Science and Technology National University of Defense Technology Changsha China

Place recognition is a crucial component in the realm of simultaneous localization and mapping (SLAM) and autonomous driving. It can also enhance the performance of loop closure detection and global localization. LiDAR-based place recognition usually relies on global feature descriptors to accurately express the similarity between LiDAR scans. However, it is time-consuming to extract and generate the global feature descriptors from the original LiDAR data. As a result, treating LiDAR-based point clouds place recognition as a 2D image problem using range projection is becoming an increasingly common and successful strategy. Vision Transformer (ViT) is a Transformer model based on self-attention mechanism for image classification. Through self-attention mechanism, ViT out-performs CNN at modeling the global information of images. We investigate that whether ViT can be transferred to LiDAR-based place recognition tasks. Firstly, we introduce a new convolutional stem to replace the original linear embedding layer in ViT. Secondly, we establish synergy by integrating low-level fine-grained features from new convolution layer with high-level coarse-grained features from ViT by skip connections. Thirdly, we aggregate these features to construct the global feature descriptor via the NetVLAD technique. The results of experiments on KITTI confirm that our method can operate online and achieve superior performance on par with existing approaches.

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