Mathematics最新文献_第10页

Quantitative and Qualitative Analysis of Aircraft Round-Trip Times Using Phase Type Distributions 利用相位类型分布对飞机往返时间进行定量和定性分析

IF 2.4 3区数学

Mathematics Pub Date : 2024-09-09 DOI: 10.3390/math12172795

Srinivas R. Chakravarthy

{"title":"Quantitative and Qualitative Analysis of Aircraft Round-Trip Times Using Phase Type Distributions","authors":"Srinivas R. Chakravarthy","doi":"10.3390/math12172795","DOIUrl":"https://doi.org/10.3390/math12172795","url":null,"abstract":"One of the major issues facing commercial airlines is the time that it takes to board passengers. Further, most airlines wish to increase the number of trips that an aircraft can make between two or more cities. Thus, reducing the overall boarding times by a few minutes will have a significant impact on the number of trips made by an aircraft, as well as enabling improvements in key measures such as the median and 75th and 95th percentiles. Looking at such measures other than the mean is critical as it is well known that the mean can under- or overestimate the performance of any model. While there is considerable literature on the study of strategies to decrease boarding times, the same cannot be said about the study of the boarding time given a particular strategy for boarding. Thus, the focus of this paper is to study analytically (using suitable stochastic models) and numerically the impact of reducing the average time on the key measures to help the system to plan accordingly. This is achieved using a well-known probability distribution, namely the phase type distribution, to model various events involved in the boarding process. Illustrative numerical results show a reduction in the percentile values when the average boarding times are decreased. Understanding the percentiles of the boarding times, as opposed to relying only on the average boarding times, will help management to adopt a better boarding strategy that in turn will lead to an increase in the number of trips that an aircraft can make.","PeriodicalId":18303,"journal":{"name":"Mathematics","volume":"12 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142177119","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Coarse-Gridded Simulation of the Nonlinear Schrödinger Equation with Machine Learning 利用机器学习对非线性薛定谔方程进行粗网格模拟

IF 2.4 3区数学

Mathematics Pub Date : 2024-09-09 DOI: 10.3390/math12172784

Benjamin F. Akers, Kristina O. F. Williams

引用次数: 0

A Novel Brillouin and Langevin Functions Dynamic Model for Two Conflicting Social Groups: Study of R&D Processes 两个冲突社会群体的新型布里渊和朗格文函数动态模型：研发过程研究

IF 2.4 3区数学

Mathematics Pub Date : 2024-09-09 DOI: 10.3390/math12172788

Ekaterina V. Orlova

{"title":"A Novel Brillouin and Langevin Functions Dynamic Model for Two Conflicting Social Groups: Study of R&D Processes","authors":"Ekaterina V. Orlova","doi":"10.3390/math12172788","DOIUrl":"https://doi.org/10.3390/math12172788","url":null,"abstract":"We consider a two-group social conflict under the corporates’ research and development (R&D) business processes. Conflict participants are divided into two groups depending on their attitude to new ideas, technologies, and behavioral style for R&D creative problems—innovators and adapters. We reveal the contradiction that arises between the need to include both types of employees in one project team and their objectively antagonistic positions regarding the methods and approaches to R&D processes. The proposed research methodology is based on a modern post-non-classical paradigm formed on the principles of coherence, interdisciplinarity, openness, and nonlinearity, as well as a sociophysical approach to the social conflicts modeling. We use the general theories of magnetism, paramagnetism, and functions of P. Langevin and L. Brillouin to describe the dynamics of group participants’ preferences regarding the style of conflict behavior. The analogy of paramagnetism, consisting in the orienting effect of the magnetic field, is used to describe social groups interactions that have not only their own interests, but are also influenced by the opinions of opposite social groups. A two-dimensional, four-parameter map represents the dynamics of group conflict. Modeling results show that regardless of the initial states and with certain parameters of intra-group and intergroup interactions, the trajectories eventually converge to an attractor (limit cycle) in a two-dimensional space. No non-periodic or chaotic modes are identified in the two-group conflict, which determines the controllability of the described conflict. The results of the simulation experiments are used as decision support and contradictions resolution aimed at forming the required modes of the corporates’ research and development business processes and ensuring the group participants’ cohesion and depolarization. The results of testing the model at an industrial enterprise are presented.","PeriodicalId":18303,"journal":{"name":"Mathematics","volume":"7 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142177094","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Few-Shot Learning Sensitive Recognition Method Based on Prototypical Network 基于原型网络的少量学习敏感识别方法

IF 2.4 3区数学

Mathematics Pub Date : 2024-09-09 DOI: 10.3390/math12172791

Guoquan Yuan, Xinjian Zhao, Liu Li, Song Zhang, Shanming Wei

引用次数: 0

Accelerating the Speed of Convergence for High-Order Methods to Solve Equations 加快高阶方程求解方法的收敛速度

IF 2.4 3区数学

Mathematics Pub Date : 2024-09-09 DOI: 10.3390/math12172785

Ramandeep Behl, Ioannis K. Argyros, Sattam Alharbi

引用次数: 0

Enhanced Parameter Estimation of DENsity CLUstEring (DENCLUE) Using Differential Evolution 利用差分进化增强 DENsity CLUstEring (DENCLUE) 的参数估计

IF 2.4 3区数学

Mathematics Pub Date : 2024-09-09 DOI: 10.3390/math12172790

Omer Ajmal, Shahzad Mumtaz, Humaira Arshad, Abdullah Soomro, Tariq Hussain, Razaz Waheeb Attar, Ahmed Alhomoud

{"title":"Enhanced Parameter Estimation of DENsity CLUstEring (DENCLUE) Using Differential Evolution","authors":"Omer Ajmal, Shahzad Mumtaz, Humaira Arshad, Abdullah Soomro, Tariq Hussain, Razaz Waheeb Attar, Ahmed Alhomoud","doi":"10.3390/math12172790","DOIUrl":"https://doi.org/10.3390/math12172790","url":null,"abstract":"The task of finding natural groupings within a dataset exploiting proximity of samples is known as clustering, an unsupervised learning approach. Density-based clustering algorithms, which identify arbitrarily shaped clusters using spatial dimensions and neighbourhood aspects, are sensitive to the selection of parameters. For instance, DENsity CLUstEring (DENCLUE)—a density-based clustering algorithm—requires a trial-and-error approach to find suitable parameters for optimal clusters. Earlier attempts to automate the parameter estimation of DENCLUE have been highly dependent either on the choice of prior data distribution (which could vary across datasets) or by fixing one parameter (which might not be optimal) and learning other parameters. This article addresses this challenge by learning the parameters of DENCLUE through the differential evolution optimisation technique without prior data distribution assumptions. Experimental evaluation of the proposed approach demonstrated consistent performance across datasets (synthetic and real datasets) containing clusters of arbitrary shapes. The clustering performance was evaluated using clustering validation metrics (e.g., Silhouette Score, Davies–Bouldin Index and Adjusted Rand Index) as well as qualitative visual analysis when compared with other density-based clustering algorithms, such as DPC, which is based on weighted local density sequences and nearest neighbour assignments (DPCSA) and Variable KDE-based DENCLUE (VDENCLUE).","PeriodicalId":18303,"journal":{"name":"Mathematics","volume":"11 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142177096","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Design and Comparison of Fractional-Order Controllers in Flotation Cell Banks and Flotation Columns Used in Copper Extraction Processes 铜提取工艺中使用的浮选池组和浮选柱中分阶控制器的设计与比较

IF 2.4 3区数学

Mathematics Pub Date : 2024-09-09 DOI: 10.3390/math12172789

Manuel A. Duarte-Mermoud, Abdiel Ricaldi-Morales, Juan Carlos Travieso-Torres, Rafael Castro-Linares

{"title":"Design and Comparison of Fractional-Order Controllers in Flotation Cell Banks and Flotation Columns Used in Copper Extraction Processes","authors":"Manuel A. Duarte-Mermoud, Abdiel Ricaldi-Morales, Juan Carlos Travieso-Torres, Rafael Castro-Linares","doi":"10.3390/math12172789","DOIUrl":"https://doi.org/10.3390/math12172789","url":null,"abstract":"This work explores efficiency improvements in the copper flotation stage, a complex nonlinear, multivariable process subject to numerous perturbations. The primary objective is to design a fractional-order PID (FOPID) control strategy and a fractional-order model reference adaptive control (FOMRAC) system. The parameters for these controllers are optimized using the particle swarm optimization (PSO) algorithm with an objective function tailored to the control goals. This study employs models of both a bank series of five flotation cells and a flotation column. Their performance results are compared against traditional controllers, such as an integer-order PID and MRAC. The findings reveal that fractional-order controllers offer notable advantages over their integer-order counterparts, showing improved performance metrics with minimal changes to the existing control framework. This research highlights the effectiveness of fractional control in enhancing flotation processes and introduces a novel application of fractional control techniques in this area.","PeriodicalId":18303,"journal":{"name":"Mathematics","volume":"4 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142177097","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Hybrid Fuzzy Method for Performance Evaluation of City Construction 城市建设绩效评价的混合模糊法

IF 2.4 3区数学

Mathematics Pub Date : 2024-09-09 DOI: 10.3390/math12172792

Chun-Ming Yang, Chang-Hsien Hsu, Tian Chen, Shiyao Li

{"title":"Hybrid Fuzzy Method for Performance Evaluation of City Construction","authors":"Chun-Ming Yang, Chang-Hsien Hsu, Tian Chen, Shiyao Li","doi":"10.3390/math12172792","DOIUrl":"https://doi.org/10.3390/math12172792","url":null,"abstract":"Evaluating the performance of city construction not only helps optimize city functions and improve city quality, but it also contributes to the development of sustainable cities. However, most of the scoring rules for evaluating the performance of city construction are overly cumbersome and demand very high data integrity. Moreover, the properties, change scale, and scope of different evaluation indicators of city construction often lead to uncertain and ambiguous results. In this study, a hybrid fuzzy method is proposed to conduct the performance evaluation of city construction in two phases. Firstly, a city performance index (CPI) was developed by combining the means and standard deviations of indicators of city construction to address the volatility of historical statistical data as well as different types of data. Considering the sampling errors in data analysis, the parameter estimation method was used to derive the 100% × (1 − α) confidence interval of the CPI. Buckley’s fuzzy approach was then adopted to extend the statistical estimators from the CPI into fuzzy estimators, after which a fuzzy CPI was proposed. To identify the specific improvement directions for city construction, the fuzzy axiom design (fuzzy AD) method was applied to explore the relationship between the targets set by city managers and actual performance. Finally, an example of six cities in China is provided to illustrate the effectiveness and practicality of the proposed method. The results show that the performance of Chongqing on several evaluation indicators is lower than that of other cities. The proposed method takes into account the issues of uniformity and diversity in the performance evaluation of city construction. It can enable a quantitative assessment of the city construction level in all cities and provide theoretical support and a decision-making basis for relevant government departments to optimize city construction planning and scientifically formulate city construction policies.","PeriodicalId":18303,"journal":{"name":"Mathematics","volume":"151 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142177117","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A Method for Transforming Non-Convex Optimization Problem to Distributed Form 将非凸优化问题转化为分布式形式的方法

IF 2.4 3区数学

Mathematics Pub Date : 2024-09-09 DOI: 10.3390/math12172796

Oleg O. Khamisov, Oleg V. Khamisov, Todor D. Ganchev, Eugene S. Semenkin

引用次数: 0

Robust Liu Estimator Used to Combat Some Challenges in Partially Linear Regression Model by Improving LTS Algorithm Using Semidefinite Programming 通过使用半无限编程改进 LTS 算法来应对部分线性回归模型中的一些挑战的鲁棒刘估计器

IF 2.4 3区数学

Mathematics Pub Date : 2024-09-09 DOI: 10.3390/math12172787

Waleed B. Altukhaes, Mahdi Roozbeh, Nur A. Mohamed

{"title":"Robust Liu Estimator Used to Combat Some Challenges in Partially Linear Regression Model by Improving LTS Algorithm Using Semidefinite Programming","authors":"Waleed B. Altukhaes, Mahdi Roozbeh, Nur A. Mohamed","doi":"10.3390/math12172787","DOIUrl":"https://doi.org/10.3390/math12172787","url":null,"abstract":"Outliers are a common problem in applied statistics, together with multicollinearity. In this paper, robust Liu estimators are introduced into a partially linear model to combat the presence of multicollinearity and outlier challenges when the error terms are not independent and some linear constraints are assumed to hold in the parameter space. The Liu estimator is used to address the multicollinearity, while robust methods are used to handle the outlier problem. In the literature on the Liu methodology, obtaining the best value for the biased parameter plays an important role in model prediction and is still an unsolved problem. In this regard, some robust estimators of the biased parameter are proposed based on the least trimmed squares (LTS) technique and its extensions using a semidefinite programming approach. Based on a set of observations with a sample size of n, and the integer trimming parameter h ≤ n, the LTS estimator computes the hyperplane that minimizes the sum of the lowest h squared residuals. Even though the LTS estimator is statistically more effective than the widely used least median squares (LMS) estimate, it is less complicated computationally than LMS. It is shown that the proposed robust extended Liu estimators perform better than classical estimators. As part of our proposal, using Monte Carlo simulation schemes and a real data example, the performance of robust Liu estimators is compared with that of classical ones in restricted partially linear models.","PeriodicalId":18303,"journal":{"name":"Mathematics","volume":"28 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142177091","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0