首页 > 最新文献

Symmetry-Basel最新文献

英文 中文
A Secure Trajectory Planning Method for Connected Autonomous Vehicles at Mining Site 矿区联网自动驾驶车辆安全轨迹规划方法
3区 综合性期刊 Q1 Mathematics Pub Date : 2023-10-25 DOI: 10.3390/sym15111973
Han Li, Yiming Li, Peng Chen, Guizhen Yu, Yaping Liao
Recently, with the assistance of 5G networks and the Internet of Things, specialized applications of autonomous driving to mining sites have been explored, with the goal of realizing the unmanned operation of mining systems and enhancing the safety of the mining industry. After receiving the loading task, the autonomous driving system will generate a feasible trajectory for the mining truck. It requires that the trajectory be generated in advanced within a limited-time high-latency network. In addition, the secure trajectory planning for mining sites involves factors in the complex environment and an unstable network. Thus, a secure trajectory planning method for autonomous trucks at mining sites is proposed. It simplifies the planning by decoupling the planning into front-end path searching and back-end trajectory generation. First, the planner enhances the Hybrid A* search algorithm to find the hauling path within the boundary of the mining site, and then, it post-processes the path with a well-designed symmetric optimization-based method. Then, considering the interaction with other autonomous trucks, a topology-guided search method for secure decision making is proposed, considering the possibility of cybersecurity. The proposed method was validated in real scenarios of the mining environment. The results verify that the planner can generate the secure trajectory under network delay 2.0 s conditions.
最近,在5G网络和物联网的辅助下,探索了自动驾驶在采矿现场的专门应用,目的是实现采矿系统的无人操作,提高采矿业的安全性。自动驾驶系统接收装载任务后,为矿用卡车生成可行的轨迹。它要求在有限时间的高延迟网络中提前生成轨迹。此外,矿山安全轨迹规划还涉及复杂环境和不稳定网络等因素。在此基础上,提出了矿区自动驾驶卡车安全轨迹规划方法。将规划解耦为前端路径搜索和后端轨迹生成,简化了规划过程。该规划器首先对Hybrid A*搜索算法进行改进,找到矿区边界内的牵引路径,然后对路径进行基于对称优化的后处理。然后,考虑到与其他自动驾驶卡车的交互,考虑到网络安全的可能性,提出了一种拓扑引导的安全决策方法。该方法在采矿环境的实际场景中得到了验证。结果验证了规划器在网络时延2.0条件下能够生成安全轨迹。
{"title":"A Secure Trajectory Planning Method for Connected Autonomous Vehicles at Mining Site","authors":"Han Li, Yiming Li, Peng Chen, Guizhen Yu, Yaping Liao","doi":"10.3390/sym15111973","DOIUrl":"https://doi.org/10.3390/sym15111973","url":null,"abstract":"Recently, with the assistance of 5G networks and the Internet of Things, specialized applications of autonomous driving to mining sites have been explored, with the goal of realizing the unmanned operation of mining systems and enhancing the safety of the mining industry. After receiving the loading task, the autonomous driving system will generate a feasible trajectory for the mining truck. It requires that the trajectory be generated in advanced within a limited-time high-latency network. In addition, the secure trajectory planning for mining sites involves factors in the complex environment and an unstable network. Thus, a secure trajectory planning method for autonomous trucks at mining sites is proposed. It simplifies the planning by decoupling the planning into front-end path searching and back-end trajectory generation. First, the planner enhances the Hybrid A* search algorithm to find the hauling path within the boundary of the mining site, and then, it post-processes the path with a well-designed symmetric optimization-based method. Then, considering the interaction with other autonomous trucks, a topology-guided search method for secure decision making is proposed, considering the possibility of cybersecurity. The proposed method was validated in real scenarios of the mining environment. The results verify that the planner can generate the secure trajectory under network delay 2.0 s conditions.","PeriodicalId":48874,"journal":{"name":"Symmetry-Basel","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135216520","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Multiple Soliton Solutions for Coupled Modified Korteweg–de Vries (mkdV) with a Time-Dependent Variable Coefficient 时变系数耦合修正Korteweg-de Vries (mkdV)的多孤子解
3区 综合性期刊 Q1 Mathematics Pub Date : 2023-10-25 DOI: 10.3390/sym15111972
Haroon D. S. Adam, Khalid I. A. Ahmed, Mukhtar Yagoub Youssif, Marin Marin
In this manuscript, we implement analytical multiple soliton wave and singular soliton wave solutions for coupled mKdV with a time-dependent variable coefficient. Based on the similarity transformation and Hirota bilinear technique, we construct both multiple wave kink and wave singular kink solutions for coupled mKdV with a time-dependent variable coefficient. We implement the Hirota bilinear technique to compute analytical solutions for the coupled mKdV system. Such calculations are made by using a software with symbolic computation software, for instance, Maple. Recently some researchers used Maple in order to show that the bilinear method of Hirota is a straightforward technique which can be used in the approach of differential, nonlinear models. We analyzed whether the experiments proved that the procedure is effective and can be successfully used for many other mathematical models used in physics and engineering. The results of this study display that the profiles of multiple-kink and singular-kink soliton types can be efficiently controlled by selecting the particular form of a similar time variable. The changes in the solitons based on the changes in the arbitrary function of time allows for more applications of them in applied sciences.
在本文中,我们实现了具有时变系数的耦合mKdV的多孤子波和奇异孤子波解析解。基于相似变换和Hirota双线性技术,构造了具有时变系数的耦合mKdV的多重波扭结解和波奇异扭结解。我们实现了Hirota双线性技术来计算耦合mKdV系统的解析解。这种计算是通过使用符号计算软件,如Maple软件来完成的。最近一些研究者使用Maple来证明Hirota的双线性方法是一种简单的技术,可以用于微分、非线性模型的处理。我们分析了实验是否证明该方法是有效的,并且可以成功地用于物理和工程中使用的许多其他数学模型。研究结果表明,通过选择相似时间变量的特定形式,可以有效地控制多扭结和单扭结孤子类型的轮廓。随着任意时间函数的变化,孤子的变化使得它们在应用科学中有了更多的应用。
{"title":"Multiple Soliton Solutions for Coupled Modified Korteweg–de Vries (mkdV) with a Time-Dependent Variable Coefficient","authors":"Haroon D. S. Adam, Khalid I. A. Ahmed, Mukhtar Yagoub Youssif, Marin Marin","doi":"10.3390/sym15111972","DOIUrl":"https://doi.org/10.3390/sym15111972","url":null,"abstract":"In this manuscript, we implement analytical multiple soliton wave and singular soliton wave solutions for coupled mKdV with a time-dependent variable coefficient. Based on the similarity transformation and Hirota bilinear technique, we construct both multiple wave kink and wave singular kink solutions for coupled mKdV with a time-dependent variable coefficient. We implement the Hirota bilinear technique to compute analytical solutions for the coupled mKdV system. Such calculations are made by using a software with symbolic computation software, for instance, Maple. Recently some researchers used Maple in order to show that the bilinear method of Hirota is a straightforward technique which can be used in the approach of differential, nonlinear models. We analyzed whether the experiments proved that the procedure is effective and can be successfully used for many other mathematical models used in physics and engineering. The results of this study display that the profiles of multiple-kink and singular-kink soliton types can be efficiently controlled by selecting the particular form of a similar time variable. The changes in the solitons based on the changes in the arbitrary function of time allows for more applications of them in applied sciences.","PeriodicalId":48874,"journal":{"name":"Symmetry-Basel","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135217335","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
New Subclass of Close-to-Convex Functions Defined by Quantum Difference Operator and Related to Generalized Janowski Function 由量子差分算子定义的与广义Janowski函数相关的近凸函数的新子类
3区 综合性期刊 Q1 Mathematics Pub Date : 2023-10-25 DOI: 10.3390/sym15111974
Suha B. Al-Shaikh, Mohammad Faisal Khan, Mustafa Kamal, Naeem Ahmad
This work begins with a discussion of the quantum calculus operator theory and proceeds to develop and investigate a new family of close-to-convex functions in an open unit disk. Considering the quantum difference operator, we define and study a new subclass of close-to-convex functions connected with generalized Janowski functions. We prove the necessary and sufficient conditions for functions that belong to newly defined classes, including the inclusion relations and estimations of the coefficients. The Fekete–Szegő problem for a more general class is also discussed. The results of this investigation expand upon those of the previous study.
本工作从量子微积分算子理论的讨论开始,并继续发展和研究开单位盘上的一组新的近凸函数。考虑量子差分算子,定义并研究了一类与广义Janowski函数连通的近凸函数的新子类。我们证明了新定义类函数的充要条件,包括包含关系和系数的估计。本文还讨论了一类更一般的fekete - szegov问题。这项调查的结果在先前研究的基础上得到了扩展。
{"title":"New Subclass of Close-to-Convex Functions Defined by Quantum Difference Operator and Related to Generalized Janowski Function","authors":"Suha B. Al-Shaikh, Mohammad Faisal Khan, Mustafa Kamal, Naeem Ahmad","doi":"10.3390/sym15111974","DOIUrl":"https://doi.org/10.3390/sym15111974","url":null,"abstract":"This work begins with a discussion of the quantum calculus operator theory and proceeds to develop and investigate a new family of close-to-convex functions in an open unit disk. Considering the quantum difference operator, we define and study a new subclass of close-to-convex functions connected with generalized Janowski functions. We prove the necessary and sufficient conditions for functions that belong to newly defined classes, including the inclusion relations and estimations of the coefficients. The Fekete–Szegő problem for a more general class is also discussed. The results of this investigation expand upon those of the previous study.","PeriodicalId":48874,"journal":{"name":"Symmetry-Basel","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135168545","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
A Systematic Mapping: Exploring Internet of Everything Technologies and Innovations 系统映射:探索万物互联技术与创新
3区 综合性期刊 Q1 Mathematics Pub Date : 2023-10-24 DOI: 10.3390/sym15111964
Fazlina Mohd Ali, Nur Arzilawati Md Yunus, Nur Nabila Mohamed, Marizuana Mat Daud, Elankovan A. Sundararajan
The Internet of Everything (IoE) represents a paradigm shift in the world of connectivity. While the Internet of Things (IoT) initiated the era of interconnected devices, the IoE takes this concept to new heights by interlinking objects, individuals, data, and processes. Symmetry in IoE innovation and technology is essential for creating a harmonious and efficient ecosystem to ensure that the benefits are accessible to a broad spectrum of society while minimizing potential drawbacks. This comprehensive review paper explores the multifaceted landscape of the IoE, delving into its core concepts, enabling technologies, real-world applications, and the intricate web of challenges it presents. A focal point of this review is the diverse array of real-world applications spanning healthcare, smart cities, industry 4.0, agriculture, and sustainability. Previous works and examples illustrate how the IoE reshapes these domains, leading to greater efficiency, sustainability, and improved decision making. However, the transformative power of the IoE is accompanied by a host of challenges, including security and privacy concerns, interoperability issues, and the ethical implications of ubiquitous connectivity. These challenges are dissected in order to comprehensively understand the obstacles and potential solutions in the IoE landscape. As we stand on the cusp of an IoE-driven future, this review paper serves as a valuable resource for researchers, policy makers, and industry professionals seeking to navigate the complexities of this emerging paradigm. By illuminating the intricacies of the IoE, this review fosters a deeper appreciation for the transformative potential and the multifaceted challenges that lie ahead in the Internet of Everything era.
万物互联(IoE)代表了连接世界的范式转变。物联网(IoT)开启了设备互联的时代,而IoE通过将物体、个人、数据和流程互联,将这一概念提升到了新的高度。物联网创新和技术的对称性对于创建一个和谐高效的生态系统至关重要,以确保广泛的社会范围能够获得好处,同时最大限度地减少潜在的缺点。这篇全面的综述论文探讨了物联网的多面性,深入研究了它的核心概念、使能技术、现实世界的应用以及它所带来的复杂挑战网络。本综述的重点是涵盖医疗保健、智慧城市、工业4.0、农业和可持续性的各种实际应用。以前的工作和示例说明了物联网如何重塑这些领域,从而提高效率、可持续性和改进决策。然而,物联网的变革力量伴随着一系列挑战,包括安全和隐私问题、互操作性问题以及无处不在的连接的伦理影响。为了全面了解物联网领域的障碍和潜在解决方案,我们将对这些挑战进行剖析。当我们站在物联网驱动的未来的尖端时,这篇综述论文为研究人员、政策制定者和行业专业人士寻求驾驭这一新兴范式的复杂性提供了宝贵的资源。通过阐释错综复杂的物联网,本综述加深了对万物互联时代的变革潜力和多方面挑战的认识。
{"title":"A Systematic Mapping: Exploring Internet of Everything Technologies and Innovations","authors":"Fazlina Mohd Ali, Nur Arzilawati Md Yunus, Nur Nabila Mohamed, Marizuana Mat Daud, Elankovan A. Sundararajan","doi":"10.3390/sym15111964","DOIUrl":"https://doi.org/10.3390/sym15111964","url":null,"abstract":"The Internet of Everything (IoE) represents a paradigm shift in the world of connectivity. While the Internet of Things (IoT) initiated the era of interconnected devices, the IoE takes this concept to new heights by interlinking objects, individuals, data, and processes. Symmetry in IoE innovation and technology is essential for creating a harmonious and efficient ecosystem to ensure that the benefits are accessible to a broad spectrum of society while minimizing potential drawbacks. This comprehensive review paper explores the multifaceted landscape of the IoE, delving into its core concepts, enabling technologies, real-world applications, and the intricate web of challenges it presents. A focal point of this review is the diverse array of real-world applications spanning healthcare, smart cities, industry 4.0, agriculture, and sustainability. Previous works and examples illustrate how the IoE reshapes these domains, leading to greater efficiency, sustainability, and improved decision making. However, the transformative power of the IoE is accompanied by a host of challenges, including security and privacy concerns, interoperability issues, and the ethical implications of ubiquitous connectivity. These challenges are dissected in order to comprehensively understand the obstacles and potential solutions in the IoE landscape. As we stand on the cusp of an IoE-driven future, this review paper serves as a valuable resource for researchers, policy makers, and industry professionals seeking to navigate the complexities of this emerging paradigm. By illuminating the intricacies of the IoE, this review fosters a deeper appreciation for the transformative potential and the multifaceted challenges that lie ahead in the Internet of Everything era.","PeriodicalId":48874,"journal":{"name":"Symmetry-Basel","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135274240","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Deep Learning-Based Cross-Layer Power Allocation for Downlink Cell-Free Massive Multiple-Input–Multiple-Output Video Communication Systems 基于深度学习的下行无小区大规模多输入多输出视频通信系统跨层功率分配
3区 综合性期刊 Q1 Mathematics Pub Date : 2023-10-24 DOI: 10.3390/sym15111968
Wen-Yen Lin, Tin-Hao Chang, Shu-Ming Tseng
We propose a deep learning-based cross-layer power allocation method for asymmetric cell-free massive MIMO video communication systems. The proposed cross-layer approach considers physical layer channel state information (CSI) and the application layer rate distortion (RD) function, and it aims to enhance video quality in terms of peak signal-to-noise ratio (PSNR). Our study develops a decentralized deep neural network (DNN) model to capture intricate system patterns, enabling accurate and efficient power allocation decisions. The proposed cross-layer approach includes unsupervised and hybrid (supervised/unsupervised) learning models. The numerical results show that the hybrid method achieves convergence with just 50% of the iterations required by the unsupervised learning model and that it achieves a 1 dB gain in PSNR over the baseline physical layer scheme.
针对非对称无小区大规模MIMO视频通信系统,提出了一种基于深度学习的跨层功率分配方法。该跨层方法考虑了物理层信道状态信息(CSI)和应用层速率失真(RD)函数,旨在从峰值信噪比(PSNR)方面提高视频质量。我们的研究开发了一个分散的深度神经网络(DNN)模型来捕获复杂的系统模式,从而实现准确有效的功率分配决策。提出的跨层方法包括无监督和混合(监督/无监督)学习模型。数值结果表明,混合方法的收敛速度仅为无监督学习模型所需迭代次数的50%,并且比基线物理层方案的PSNR增益为1 dB。
{"title":"Deep Learning-Based Cross-Layer Power Allocation for Downlink Cell-Free Massive Multiple-Input–Multiple-Output Video Communication Systems","authors":"Wen-Yen Lin, Tin-Hao Chang, Shu-Ming Tseng","doi":"10.3390/sym15111968","DOIUrl":"https://doi.org/10.3390/sym15111968","url":null,"abstract":"We propose a deep learning-based cross-layer power allocation method for asymmetric cell-free massive MIMO video communication systems. The proposed cross-layer approach considers physical layer channel state information (CSI) and the application layer rate distortion (RD) function, and it aims to enhance video quality in terms of peak signal-to-noise ratio (PSNR). Our study develops a decentralized deep neural network (DNN) model to capture intricate system patterns, enabling accurate and efficient power allocation decisions. The proposed cross-layer approach includes unsupervised and hybrid (supervised/unsupervised) learning models. The numerical results show that the hybrid method achieves convergence with just 50% of the iterations required by the unsupervised learning model and that it achieves a 1 dB gain in PSNR over the baseline physical layer scheme.","PeriodicalId":48874,"journal":{"name":"Symmetry-Basel","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135316311","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Symmetric Adaptive Higher-Order Energy-Preserving Methods for a Charged Particle System and Guiding Center System 带电粒子系统和导向中心系统的对称自适应高阶能量守恒方法
3区 综合性期刊 Q1 Mathematics Pub Date : 2023-10-24 DOI: 10.3390/sym15111969
Beibei Zhu, Hongji Zhou
We propose higher-order adaptive energy-preserving methods for a charged particle system and a guiding center system. The higher-order energy-preserving methods are symmetric and are constructed by composing the second-order energy-preserving methods based on the averaged vector field. In order to overcome the energy drift problem that occurs in the energy-preserving methods based on the average vector field, we develop two adaptive algorithms for the higher-order energy-preserving methods. The two adaptive algorithms are developed based on using variable points of Gauss–Legendre’s quadrature rule and using two different stepsizes. The numerical results show that the two adaptive algorithms behave better in phase portrait and energy conservation than the Runge–Kutta methods. Moreover, it is shown that the energy errors obtained by the two adaptive algorithms can be bounded by the machine precision over long time and do not show energy drift.
我们提出了带电粒子系统和导向中心系统的高阶自适应能量守恒方法。高阶保能方法是对称的,由基于平均向量场的二阶保能方法组合而成。为了克服基于平均向量场的能量守恒方法中存在的能量漂移问题,我们开发了两种高阶能量守恒方法的自适应算法。基于高斯-勒让德正交规则的可变点,采用两种不同的步长,提出了两种自适应算法。数值结果表明,两种自适应算法在相位刻画和能量节约方面都优于龙格-库塔方法。结果表明,两种自适应算法得到的能量误差在较长时间内都能以机器精度为界,且不存在能量漂移。
{"title":"Symmetric Adaptive Higher-Order Energy-Preserving Methods for a Charged Particle System and Guiding Center System","authors":"Beibei Zhu, Hongji Zhou","doi":"10.3390/sym15111969","DOIUrl":"https://doi.org/10.3390/sym15111969","url":null,"abstract":"We propose higher-order adaptive energy-preserving methods for a charged particle system and a guiding center system. The higher-order energy-preserving methods are symmetric and are constructed by composing the second-order energy-preserving methods based on the averaged vector field. In order to overcome the energy drift problem that occurs in the energy-preserving methods based on the average vector field, we develop two adaptive algorithms for the higher-order energy-preserving methods. The two adaptive algorithms are developed based on using variable points of Gauss–Legendre’s quadrature rule and using two different stepsizes. The numerical results show that the two adaptive algorithms behave better in phase portrait and energy conservation than the Runge–Kutta methods. Moreover, it is shown that the energy errors obtained by the two adaptive algorithms can be bounded by the machine precision over long time and do not show energy drift.","PeriodicalId":48874,"journal":{"name":"Symmetry-Basel","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135266601","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
A New Model for Determining Factors Affecting Human Errors in Manual Assembly Processes Using Fuzzy Delphi and DEMATEL Methods 用模糊德尔菲和DEMATEL方法确定人工装配过程中人为错误影响因素的新模型
3区 综合性期刊 Q1 Mathematics Pub Date : 2023-10-24 DOI: 10.3390/sym15111967
Fahad M. Alqahtani, Mohammed A. Noman, Saad A. Alabdulkarim, Ibrahim Alharkan, Mohammed H. Alhaag, Faisal M. Alessa
Human errors (HEs) are common problems in manual assembly processes, impacting product quality and resulting in additional costs. Based on expert judgments, this study aims to identify the most significant factors affecting HEs in manual assembly processes and explore the cause-and-effect relationships among those factors. In order to achieve this objective, a proposed model is constructed using two types of Multi-Criteria Decision-Making (MCDM) techniques. Firstly, using two rounds of the fuzzy Delphi method (FDM), twenty-seven factors with an influence score of 0.7 or higher were found to have a major impact on HEs during manual assembly processes, with at least a 75% consensus among experts. After that, the twenty-seven factors affecting HEs were given to experts in a third round to analyze the cause-and-effect relationships among those factors using the fuzzy decision-making trial and evaluation laboratory (DEMATEL) method. In MCDM techniques, symmetry refers to an important property that can be used to find relationships between variables. It is based on the principle that the relative importance or preference between two variables should remain the same regardless of their positions or roles. Therefore, symmetry is a factor that MCDM approaches take into account to ensure that the relationships between variables are accurately represented, leading to more reliable decision-making outcomes. The reliability and normality of the surveying data were examined using the SPSS 22.0 software program. The study results revealed that training level, poor workplace layout, a lack of necessary tools, and experience were the major factors affecting HEs as root causes. Moreover, a failure to address the error-causing problem, unintentional unsafe acts, fatigue, and poor error visual perception were found to be effect (dependent) factors. The findings of this study can help organizations make better-informed decisions on how to reduce worker errors and interest in the factors that contribute to assembly errors and provide a good basis for reaching the quality of final assembled parts.
人为错误(HEs)是人工组装过程中的常见问题,会影响产品质量并导致额外的成本。在专家判断的基础上,本研究旨在找出影响手工装配过程HEs的最显著因素,并探讨这些因素之间的因果关系。为了实现这一目标,采用两种多准则决策(MCDM)技术构建了一个模型。首先,采用两轮模糊德尔菲法(FDM),发现27个影响得分在0.7及以上的因素对人工装配过程中的HEs有重大影响,专家的共识度至少为75%。然后,第三轮将27个影响HEs的因素交给专家,采用模糊决策试验与评价实验室(DEMATEL)方法分析各因素之间的因果关系。在MCDM技术中,对称性是一种重要的属性,可以用来发现变量之间的关系。它所依据的原则是,无论两个变量的位置或作用如何,它们之间的相对重要性或偏好应该保持不变。因此,对称性是MCDM方法考虑的一个因素,以确保变量之间的关系得到准确表示,从而产生更可靠的决策结果。采用SPSS 22.0软件对调查数据的信度和正态性进行检验。研究结果显示,培训水平、工作场所布局不良、缺乏必要的工具和经验是影响医疗服务人员的主要因素。此外,未能解决导致错误的问题,无意的不安全行为,疲劳和错误视觉感知差被发现是影响(依赖)因素。本研究的结果可以帮助组织在如何减少工人错误和对导致装配错误的因素的兴趣方面做出更明智的决策,并为达到最终装配零件的质量提供良好的基础。
{"title":"A New Model for Determining Factors Affecting Human Errors in Manual Assembly Processes Using Fuzzy Delphi and DEMATEL Methods","authors":"Fahad M. Alqahtani, Mohammed A. Noman, Saad A. Alabdulkarim, Ibrahim Alharkan, Mohammed H. Alhaag, Faisal M. Alessa","doi":"10.3390/sym15111967","DOIUrl":"https://doi.org/10.3390/sym15111967","url":null,"abstract":"Human errors (HEs) are common problems in manual assembly processes, impacting product quality and resulting in additional costs. Based on expert judgments, this study aims to identify the most significant factors affecting HEs in manual assembly processes and explore the cause-and-effect relationships among those factors. In order to achieve this objective, a proposed model is constructed using two types of Multi-Criteria Decision-Making (MCDM) techniques. Firstly, using two rounds of the fuzzy Delphi method (FDM), twenty-seven factors with an influence score of 0.7 or higher were found to have a major impact on HEs during manual assembly processes, with at least a 75% consensus among experts. After that, the twenty-seven factors affecting HEs were given to experts in a third round to analyze the cause-and-effect relationships among those factors using the fuzzy decision-making trial and evaluation laboratory (DEMATEL) method. In MCDM techniques, symmetry refers to an important property that can be used to find relationships between variables. It is based on the principle that the relative importance or preference between two variables should remain the same regardless of their positions or roles. Therefore, symmetry is a factor that MCDM approaches take into account to ensure that the relationships between variables are accurately represented, leading to more reliable decision-making outcomes. The reliability and normality of the surveying data were examined using the SPSS 22.0 software program. The study results revealed that training level, poor workplace layout, a lack of necessary tools, and experience were the major factors affecting HEs as root causes. Moreover, a failure to address the error-causing problem, unintentional unsafe acts, fatigue, and poor error visual perception were found to be effect (dependent) factors. The findings of this study can help organizations make better-informed decisions on how to reduce worker errors and interest in the factors that contribute to assembly errors and provide a good basis for reaching the quality of final assembled parts.","PeriodicalId":48874,"journal":{"name":"Symmetry-Basel","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135267076","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Wind-Induced Vibrations and Gust Response Factors of the Cabin–Cable–Tower System 舱室-索-塔系统的风致振动及阵风响应系数
3区 综合性期刊 Q1 Mathematics Pub Date : 2023-10-24 DOI: 10.3390/sym15111965
De-Xiu Mo, Hong-Nan Li, Qing-Wei Li
A large-scale radio astronomical telescope is a typical complex coupled system, consisting of a feed cabin, cables, and supporting structures. The system is extremely sensitive to wind loads, especially the feed cabin, which has high requirements for vibration displacement during operation, and excessive vibration may affect normal operation. To investigate the wind-induced vibration characteristics of such coupled systems, this study takes the Five-hundred-meter Aperture Spherical Radio Telescope (FAST) as an example to conduct research. First, a refined finite element model of FAST is established, and a dynamic analysis using simulated random wind loads is conducted. The influence of the cable boundary on the time–frequency domain responses of the feed cabin is particularly considered. Then, the gust response factor (GRF) for different structural components within the coupled system is calculated. Finally, the evolution law of the GRF under various wind speeds and directions is revealed by parametric analysis. The parameter analysis only considers the wind directions ranging from 0° to 60°, because FAST is a symmetric structure. The results indicate that obvious differences are observed in both the rotational and translational displacements of the feed cabin under northward wind, especially the results along the east–west axis. When the supporting towers are considered, there is no change in the power spectral density (PSD) of the feed cabin in the low-frequency range. However, in the high-frequency range, taking the supporting towers into account leads to an increase in PSD and a resonance near the first-order natural frequency of the supporting tower. The GRF based on the dynamic response exhibits substantial deviations compared to those obtained from design codes, highlighting the need for an independent analysis when determining GRF for such coupled systems.
大型射电天文望远镜是一个典型的复杂耦合系统,由馈源舱、电缆和支撑结构组成。系统对风荷载极为敏感,尤其是进料舱,在运行过程中对振动位移有很高的要求,过大的振动可能会影响正常运行。为了研究这类耦合系统的风致振动特性,本研究以500米口径球面射电望远镜(FAST)为例进行研究。首先,建立了FAST的精细化有限元模型,并进行了模拟随机风荷载的动力分析。特别考虑了电缆边界对馈电舱时频域响应的影响。然后,计算了耦合系统中不同结构构件的阵风响应因子(GRF)。最后,通过参数分析揭示了不同风速和风向下GRF的演化规律。由于FAST为对称结构,故参数分析只考虑0°~ 60°风向范围。结果表明:在北风作用下,进料舱的转动和平动位移有明显的差异,特别是在东西方向上的差异较大;在考虑支撑塔的情况下,低频范围内进料舱功率谱密度(PSD)没有变化。然而,在高频范围内,考虑支承塔会导致PSD增加,并且在支承塔一阶固有频率附近产生共振。与设计规范相比,基于动态响应的GRF存在较大偏差,这突出表明在确定此类耦合系统的GRF时需要进行独立分析。
{"title":"Wind-Induced Vibrations and Gust Response Factors of the Cabin–Cable–Tower System","authors":"De-Xiu Mo, Hong-Nan Li, Qing-Wei Li","doi":"10.3390/sym15111965","DOIUrl":"https://doi.org/10.3390/sym15111965","url":null,"abstract":"A large-scale radio astronomical telescope is a typical complex coupled system, consisting of a feed cabin, cables, and supporting structures. The system is extremely sensitive to wind loads, especially the feed cabin, which has high requirements for vibration displacement during operation, and excessive vibration may affect normal operation. To investigate the wind-induced vibration characteristics of such coupled systems, this study takes the Five-hundred-meter Aperture Spherical Radio Telescope (FAST) as an example to conduct research. First, a refined finite element model of FAST is established, and a dynamic analysis using simulated random wind loads is conducted. The influence of the cable boundary on the time–frequency domain responses of the feed cabin is particularly considered. Then, the gust response factor (GRF) for different structural components within the coupled system is calculated. Finally, the evolution law of the GRF under various wind speeds and directions is revealed by parametric analysis. The parameter analysis only considers the wind directions ranging from 0° to 60°, because FAST is a symmetric structure. The results indicate that obvious differences are observed in both the rotational and translational displacements of the feed cabin under northward wind, especially the results along the east–west axis. When the supporting towers are considered, there is no change in the power spectral density (PSD) of the feed cabin in the low-frequency range. However, in the high-frequency range, taking the supporting towers into account leads to an increase in PSD and a resonance near the first-order natural frequency of the supporting tower. The GRF based on the dynamic response exhibits substantial deviations compared to those obtained from design codes, highlighting the need for an independent analysis when determining GRF for such coupled systems.","PeriodicalId":48874,"journal":{"name":"Symmetry-Basel","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135273097","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Neutrino Oscillations in Finite Time Path Out-of-Equilibrium Thermal Field Theory 有限时间路径非平衡热场理论中的中微子振荡
3区 综合性期刊 Q1 Mathematics Pub Date : 2023-10-24 DOI: 10.3390/sym15111970
Ivan Dadić, Dubravko Klabučar
We demonstrate that the Finite-Time-Path Field Theory is an adequate tool for calculating neutrino oscillations. We apply this theory using a mass-mixing Lagrangian which involves the correct Dirac spin and chirality structure and a Pontecorvo–Maki–Nakagawa–Sakata (PMNS)-like mixing matrix. The model is exactly solvable. The Dyson–Schwinger equations transform propagators of the input free (massless) flavor neutrinos into a linear combination of oscillating (massive) neutrinos. The results are consistent with the predictions of the PMNS matrix while allowing for extrapolation to early times.
我们证明了有限时间路径场论是计算中微子振荡的适当工具。我们使用了包含正确的狄拉克自旋和手性结构的质量混合拉格朗日量和类似Pontecorvo-Maki-Nakagawa-Sakata (PMNS)的混合矩阵来应用这一理论。模型是精确可解的。Dyson-Schwinger方程将输入自由(无质量)中微子的传播子转换为振荡(有质量)中微子的线性组合。结果与PMNS矩阵的预测一致,同时允许外推到早期。
{"title":"Neutrino Oscillations in Finite Time Path Out-of-Equilibrium Thermal Field Theory","authors":"Ivan Dadić, Dubravko Klabučar","doi":"10.3390/sym15111970","DOIUrl":"https://doi.org/10.3390/sym15111970","url":null,"abstract":"We demonstrate that the Finite-Time-Path Field Theory is an adequate tool for calculating neutrino oscillations. We apply this theory using a mass-mixing Lagrangian which involves the correct Dirac spin and chirality structure and a Pontecorvo–Maki–Nakagawa–Sakata (PMNS)-like mixing matrix. The model is exactly solvable. The Dyson–Schwinger equations transform propagators of the input free (massless) flavor neutrinos into a linear combination of oscillating (massive) neutrinos. The results are consistent with the predictions of the PMNS matrix while allowing for extrapolation to early times.","PeriodicalId":48874,"journal":{"name":"Symmetry-Basel","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135266599","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Action Principle for Scale Invariance and Applications (Part I) 尺度不变性的作用原理及其应用(第一部分)
3区 综合性期刊 Q1 Mathematics Pub Date : 2023-10-24 DOI: 10.3390/sym15111966
Andre Maeder, Vesselin G. Gueorguiev
On the basis of a general action principle, we revisit the scale invariant field equation using the cotensor relations by Dirac (1973). This action principle also leads to an expression for the scale factor λ, which corresponds to the one derived from the gauging condition, which assumes that a macroscopic empty space is scale-invariant, homogeneous, and isotropic. These results strengthen the basis of the scale-invariant vacuum (SIV) paradigm. From the field and geodesic equations, we derive, in current time units (years, seconds), the Newton-like equation, the equations of the two-body problem, and its secular variations. In a two-body system, orbits very slightly expand, while the orbital velocity keeps constant during expansion. Interestingly enough, Kepler’s third law is a remarkable scale-invariant property.
在一般作用原理的基础上,我们用狄拉克(1973)的协张量关系重新讨论了尺度不变场方程。这一作用原理也导致了尺度因子λ的表达式,它对应于测量条件,假设宏观空间是尺度不变的,均匀的,各向同性。这些结果加强了尺度不变真空(SIV)范式的基础。从场方程和测地线方程中,我们以当前的时间单位(年、秒)推导出类牛顿方程、二体问题方程及其长期变化。在双体系统中,轨道会轻微膨胀,而在膨胀过程中轨道速度保持恒定。有趣的是,开普勒第三定律是一个显著的尺度不变性质。
{"title":"Action Principle for Scale Invariance and Applications (Part I)","authors":"Andre Maeder, Vesselin G. Gueorguiev","doi":"10.3390/sym15111966","DOIUrl":"https://doi.org/10.3390/sym15111966","url":null,"abstract":"On the basis of a general action principle, we revisit the scale invariant field equation using the cotensor relations by Dirac (1973). This action principle also leads to an expression for the scale factor λ, which corresponds to the one derived from the gauging condition, which assumes that a macroscopic empty space is scale-invariant, homogeneous, and isotropic. These results strengthen the basis of the scale-invariant vacuum (SIV) paradigm. From the field and geodesic equations, we derive, in current time units (years, seconds), the Newton-like equation, the equations of the two-body problem, and its secular variations. In a two-body system, orbits very slightly expand, while the orbital velocity keeps constant during expansion. Interestingly enough, Kepler’s third law is a remarkable scale-invariant property.","PeriodicalId":48874,"journal":{"name":"Symmetry-Basel","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135268102","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 1
期刊
Symmetry-Basel
全部 Acc. Chem. Res. ACS Applied Bio Materials ACS Appl. Electron. Mater. ACS Appl. Energy Mater. ACS Appl. Mater. Interfaces ACS Appl. Nano Mater. ACS Appl. Polym. Mater. ACS BIOMATER-SCI ENG ACS Catal. ACS Cent. Sci. ACS Chem. Biol. ACS Chemical Health & Safety ACS Chem. Neurosci. ACS Comb. Sci. ACS Earth Space Chem. ACS Energy Lett. ACS Infect. Dis. ACS Macro Lett. ACS Mater. Lett. ACS Med. Chem. Lett. ACS Nano ACS Omega ACS Photonics ACS Sens. ACS Sustainable Chem. Eng. ACS Synth. Biol. Anal. Chem. BIOCHEMISTRY-US Bioconjugate Chem. BIOMACROMOLECULES Chem. Res. Toxicol. Chem. Rev. Chem. Mater. CRYST GROWTH DES ENERG FUEL Environ. Sci. Technol. Environ. Sci. Technol. Lett. Eur. J. Inorg. Chem. IND ENG CHEM RES Inorg. Chem. J. Agric. Food. Chem. J. Chem. Eng. Data J. Chem. Educ. J. Chem. Inf. Model. J. Chem. Theory Comput. J. Med. Chem. J. Nat. Prod. J PROTEOME RES J. Am. Chem. Soc. LANGMUIR MACROMOLECULES Mol. Pharmaceutics Nano Lett. Org. Lett. ORG PROCESS RES DEV ORGANOMETALLICS J. Org. Chem. J. Phys. Chem. J. Phys. Chem. A J. Phys. Chem. B J. Phys. Chem. C J. Phys. Chem. Lett. Analyst Anal. Methods Biomater. Sci. Catal. Sci. Technol. Chem. Commun. Chem. Soc. Rev. CHEM EDUC RES PRACT CRYSTENGCOMM Dalton Trans. Energy Environ. Sci. ENVIRON SCI-NANO ENVIRON SCI-PROC IMP ENVIRON SCI-WAT RES Faraday Discuss. Food Funct. Green Chem. Inorg. Chem. Front. Integr. Biol. J. Anal. At. Spectrom. J. Mater. Chem. A J. Mater. Chem. B J. Mater. Chem. C Lab Chip Mater. Chem. Front. Mater. Horiz. MEDCHEMCOMM Metallomics Mol. Biosyst. Mol. Syst. Des. Eng. Nanoscale Nanoscale Horiz. Nat. Prod. Rep. New J. Chem. Org. Biomol. Chem. Org. Chem. Front. PHOTOCH PHOTOBIO SCI PCCP Polym. Chem.
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
0
微信
客服QQ
Book学术公众号 扫码关注我们
反馈
×
意见反馈
请填写您的意见或建议
请填写您的手机或邮箱
×
提示
您的信息不完整,为了账户安全,请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
现在去查看 取消
×
提示
确定
Book学术官方微信
Book学术文献互助
Book学术文献互助群
群 号:481959085
Book学术
文献互助 智能选刊 最新文献 互助须知 联系我们:info@booksci.cn
Book学术提供免费学术资源搜索服务,方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。
Copyright © 2023 Book学术 All rights reserved.
ghs 京公网安备 11010802042870号 京ICP备2023020795号-1