14,709 results
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2. A novel artificial neural network approach for residual life estimation of paper insulation in oil‐immersed power transformers.
- Author
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Nezami, Md. Manzar, Equbal, Md. Danish, Ansari, Md. Fahim, Alotaibi, Majed A., Malik, Hasmat, García Márquez, Fausto Pedro, and Hossaini, Mohammad Asef
- Subjects
- *
ARTIFICIAL neural networks , *POWER transformers , *TRANSFORMER insulation , *ARTIFICIAL intelligence , *MATHEMATICAL optimization - Abstract
Avoiding financial losses requires preventing catastrophic oil‐filled power transformer breakdowns. Continuous online transformer monitoring is needed. The authors use paper insulation to evaluate transformer health for continuous online transformer monitoring. The study suggests a new artificial intelligence method for estimating paper insulation residual life in oil‐immersed power transformers. The four artificial intelligence models use backpropagation‐based neural networks to predict paper insulation lifespan. Four primary transformer insulating paper failure indices—degree of polymerisation, 2‐furfuraldehyde, carbon monoxide, and carbon dioxide—form the basis of these models. Each model, including the backpropagation‐based neural networks, estimates paper insulation life using one failure index, along with moisture and temperature data. Optimisation techniques enhance hidden layer neurons and epoch count for improved performance. Results are validated against literature‐based life models, establishing a precise input–output correlation. This method accurately predicts the remaining useable life of power transformer paper insulation, enabling utilities to take proactive measures for safe and efficient transformer operation. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
3. Scheduling Heating Tasks on Parallel Furnaces with Setup Times and Conflicts
- Author
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Lange, Julia, Fath, Philipp, Sayah, David, Barbosa-Povoa, Ana Paula, Editorial Board Member, de Almeida, Adiel Teixeira, Editorial Board Member, Gans, Noah, Editorial Board Member, Gupta, Jatinder N. D., Editorial Board Member, Heim, Gregory R., Editorial Board Member, Hua, Guowei, Editorial Board Member, Kimms, Alf, Editorial Board Member, Li, Xiang, Editorial Board Member, Masri, Hatem, Editorial Board Member, Nickel, Stefan, Editorial Board Member, Qiu, Robin, Editorial Board Member, Shankar, Ravi, Editorial Board Member, Slowiński, Roman, Editorial Board Member, Tang, Christopher S., Editorial Board Member, Wu, Yuzhe, Editorial Board Member, Zhu, Joe, Editorial Board Member, Zopounidis, Constantin, Editorial Board Member, Trautmann, Norbert, editor, and Gnägi, Mario, editor
- Published
- 2022
- Full Text
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4. Theoretical analysis and design of roller mower straight blade.
- Author
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Zhang, Lingyan, Yao, Cheng, Ying, Weiqiang, Luo, Shijian, and Ying, Fangtian
- Subjects
- *
PAPER arts , *MATHEMATICAL optimization , *STRUCTURAL optimization , *ENERGY consumption , *CONSUMPTION (Economics) - Abstract
In order to study the cutting performance of the straight edge hob and reduce the cutting power consumption model of the straight edge hob, this paper takes the cutting power of the straight edge hob as the minimum goal, and establishes the mathematical model of the optimization design of the straight edge hob based on the composite optimization method. The mathematical model is solved by MATLAB software. At the same time,the mowing characteristics of a roller blade were studied by investigating the relationship between the hob and the coordination of variables such as rotational speed and roller diameter with the mowing parameters. The parameter analysis of straight edge hob before and after structural parameter optimization is generated, and a design method is proposed based on this. After defining the objective function and constraint conditions, the influence of structural parameters on the power consumption and efficiency of the hob was determined by optimising the complex method; this could significantly adjust the hob parameters to lower its power consumption. The energy consumption of the optimized design is reduced by 11.1 % compared with the original scheme, and the optimization effect is remarkable. The results show that the best working parameters of the hob are cutting speed of 1000 r/min, sliding cutting angle and grinding edge angle of 25~30°. Moreover, practical tests demonstrated the feasibility of using the proposed method to design the straight edge hob to improve mowing performance and hob stability. This study can provide parameter foundation and an optimization method for lowering chopping power consumption of the roller mower blade. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
5. Web Development and Performance Comparison of Web Development Frameworks: A Review Paper.
- Author
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Vayadande, Kuldeep, Purohit, Shlok, Rathod, Chaitanya, Rathod, Manish, Rathi, Parth, and Rathi, Purvesh
- Subjects
WEB development ,HEALTH websites ,MATHEMATICAL optimization ,OPTICAL disks ,DECISION making ,SCALABILITY - Abstract
Web development frameworks help in streamlining and speedy-tracking the system of constructing web packages. There is an array of frameworks which makes it hard for developers to decide the nice option to use in their tasks. This survey paper is extensive and a comparative internet development framework, thinking about the primary additives, strengths and weaknesses of every utility. This paper involves stringent assessment technique for performance measurement metrics inclusive of reaction time, scalability, and memory. Optimization of techniques and the issues on protection for each framework also are taken into consideration. To wrap up, this paper offers steering to be able to help the readers to choose the most appropriate framework depending on their task needs. The data offered on this survey are supposed to guide developers as well as decision makers towards making quality decisions that culminate in appropriate utility on websites. [ABSTRACT FROM AUTHOR]
- Published
- 2024
6. The Collected Papers of Leonid Hurwicz : Volume 1
- Author
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Samiran Banerjee and Samiran Banerjee
- Subjects
- Economics, Mathematical, Mathematical optimization
- Abstract
Leonid Hurwicz (1917-2008) was a major figure in modern theoretical economics whose contributions over sixty-five years spanned at least five areas: econometrics, nonlinear programming, decision theory, microeconomic theory, and mechanism design. In 2007, at age ninety, he received the Nobel Memorial Prize in Economics (shared with Eric Maskin and Roger Myerson) for pioneering the field of mechanism design and incentive compatibility. Hurwicz made seminal contributions in the other areas as well. In non-linear programming, he contributed to the understanding of Lagrange-Kuhn-Tucker problems (along with co-authors Kenneth Arrowand Hirofumi Uzawa). In econometrics, the Hurwicz bias in the least-squares analysis of time series is a fundamental and commonly cited benchmark. In decision theory, the Hurwicz criterion for decision-making under ambiguity is routinely invoked, sometimes without a citation since his original paper was never published. In microeconomic theory, Hurwicz (along with Arrow and H.D. Block) initiated the study of stability of the market mechanism, and (with Uzawa) solved the classic integrability of demand problem, a core result in neoclassical consumer theory. While some of Hurwicz's work were published in journals, many remain scattered as chapters in books which are difficult to access; yet others were never published at all. The Collected Papers of Leonid Hurwicz is the first volume in a series of four that will bring his oeuvre in one place, to bring to light the totality of his intellectual output, to document his contribution to economics and the extent of his legacy, with the express purpose to make it easily available for future generations of researchers to build upon.
- Published
- 2022
7. Trend and current practices of coagulation-based hybrid systems for pulp and paper mill effluent treatment: mechanisms, optimization techniques and performance evaluation.
- Author
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Jagaba, Ahmad Hussaini, Birniwa, Abdullahi Haruna, Usman, Abdullahi Kilaco, Mu'azu, Nuhu Dalhat, Yaro, Nura Shehu Aliyu, Soja, Usman Bala, Abioye, Kunmi Joshua, Almahbashi, Najib Mohammed Yahya, Al-dhawi, Baker Nasser Saleh, Noor, Azmatullah, and Lawal, Ibrahim Mohammed
- Subjects
- *
WATER purification , *HYBRID systems , *PAPER pulp , *MATHEMATICAL optimization , *PULP mills , *SANITATION , *DECONTAMINATION (From gases, chemicals, etc.) - Abstract
This paper presents an overview of pulp and paper mills (PPM) production processes, the resulting release of wastewater effluent loaded with wide range of pollutants and associated environmental impacts. The review highlighted the different types of functional materials and their modified forms employed as coagulants for pulp and paper mills industries effluent (PPME) treatment that have been intensively studied as a promising strategy for PPM to achieve cleaner and sustainable treatments in accordance with sustainable development goals (SDGs) "6-Clean water and sanitation", "9-Industry, innovation, and infrastructure", and "12-Responsible consumption and production". Standalone coagulation treatment processes are inherently ineffective towards meeting the increasingly stringent discharge requirements, coupled with their higher energy demand, and increased operational and maintenance costs. Owing to the recalcitrant nature of PPME contaminants, this review explored the effectiveness of the coagulation processes for decontamination of PPME. Furthermore, the review provides a state-of-the-art coagulation-based hybrid systems employed for enhanced PPME treatment. The process limitations, influencing factors and optimization techniques are highlighted. The review also highlights how sustained research in the subject area impacts on achieving cleaner production. The review also discusses coagulant classifications and the synergistic, antagonistic and shock load toxic effects of hybrid coagulants on toxicant biodegradation and their associated system efficiency. Moreover, it offers a guide for the development and application of sustainable hybrid-based coagulants for PPME treatment. The findings presented herein provide a vital theoretical foundation for sustainable solutions to improve coagulation-based hybrid systems efficiency and their scale-up towards potential commercialization. [Display omitted] • Pulp and paper mills produce effluents containing diverse and emerging contaminants. • Different materials and their modified forms are used as coagulants for PPME treatment. • The synergistic and shock load toxic effects of hybrid-based coagulants could be identified. • Hybrid systems are highly efficient techniques for PPME treatment. • The review highlights process weaknesses, influencing factors and optimization techniques. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
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8. A note on the paper 'Necessary and sufficient optimality conditions using convexifactors for mathematical programs with equilibrium constraints'
- Author
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N. Gadhi
- Subjects
Mathematical optimization ,Work (electrical) ,Computer science ,Management Science and Operations Research ,Fault (power engineering) ,Computer Science Applications ,Theoretical Computer Science ,Counterexample - Abstract
In this work, some counterexamples are given to refute some results in the paper by Kohli [RAIRO:OR 53 (2019) 1617–1632]. We correct the fault in some of his results.
- Published
- 2021
9. Topological optimization of the stiffness of an irregular structure based on an element size independent filter.
- Author
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Diao, Shijing, Wang, Deshi, and Wang, Xudong
- Subjects
- *
STRUCTURAL optimization , *FILTER paper , *CONSTRUCTION materials , *MATHEMATICAL optimization - Abstract
Because of the overly averaged element sensitivity in the topological optimization of an irregular structure with a grid independent filter, a topological optimization model was built for the structural domain. The maximization of stiffness was first taken as the goal for the topological optimization of irregular structure stiffness. Subsequently, an element size filter was proposed to address the overly averaged local element sensitivity with the grid independent filter when the designed domain element size varied dramatically. Finally, the element sensitivity of the objective function was derived under the given constraints. A case study was then conducted on a naval gun mount with the maximization of structural flexibility as the objective function and the volume of structural material as a constraint. A stiffness optimization model based on the bi-directional evolutionary structural optimization algorithm was adopted for the topological optimization of the gun mount. Structural optimization was conducted for the gun mount with different shooting angles to realize its optimal stiffness and strength under the constraint of consistent material volume. The optimization results proved that the element independent filter proposed in this paper could be effectively applied in the topological optimization of an irregular structure and used to explore the topological optimization of the supporting structure under impact. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
10. The UAM service network: multi-objective and multi-period design for UAM airports
- Author
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Boo, Jeongjoon, Lee, Seung Yeob, and Song, Byung Duk
- Published
- 2023
- Full Text
- View/download PDF
11. Preface for the Special Issue Optimization, Variational Analysis, and Applications in Honor of Professor Franco Giannessi.
- Author
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Ansari, Qamrul Hasan, Mordukhovich, Boris S., and Pappalardo, Massimo
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SIMPLEX algorithm ,LINEAR complementarity problem ,MATHEMATICAL optimization ,CONTACT mechanics ,LIPSCHITZ continuity ,COMPLEMENTARITY constraints (Mathematics) - Abstract
The numerical algorithm by Cristofari et al. modifies the augmented Lagrangian method ALGENCAN proposed by Andreani and his collaborators by incorporating certain second-order information into the augmented Lagrangian framework. Professor Franco Giannessi, University of Pisa, is an outstanding mathematician whose contributions to optimization theory and its applications and to the world optimization community are difficult to overstate. The paper by Izmailov and Solodov introduces and develops a novel perturbed augmented Lagrangian method framework for constrained optimization problems. [Extracted from the article]
- Published
- 2022
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12. Reliability-Optimal Designs in MEC Networks with Finite Blocklength Codes and Outdated CSI: (Invited Paper)
- Author
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M. Cenk Gursoy, Yulin Hu, and Yang Yang
- Subjects
Reliability theory ,Mathematical optimization ,Base station ,Mobile edge computing ,Optimization problem ,Computer science ,Reliability (computer networking) ,Server ,Computational resource ,Edge computing - Abstract
There has been an increasing interest in mobile edge computing (MEC) in recent years. Different from the traditional centralized cloud computing, MEC servers are deployed at the edges of networks such as at base stations (BSs) and access points (APs), in order to support computation-intensive and latency-critical applications. In this paper, we consider a multi-user mobile edge computing (MEC) network in which the wireless data transmission/offloading is performed using finite blocklength (FBL) codes to satisfy the latency constraints. The reliability in the communication phase is characterized in the FBL regime, while the event of queue length violation in the computation phase is investigated via exploiting the extreme value theory. We first formulate the overall optimization problem in the scenario of multiple user equipments (UEs) aiming to minimize the maximal end-to-end error probability among all UEs under both the FBL and energy consumption constraints. We further propose a two-level learning-based approach to jointly determine time allocations in the FBL regime, the UEs' offloading decisions and MEC computational resource allocations to solve the overall optimization problem. Simulation results demonstrate that the proposed two-level learning-based algorithm solves the problem efficiently.
- Published
- 2021
13. The Power of Parallelism in Stochastic Search for Global Optimum: Keynote Paper
- Author
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Ali Sheikholeslami
- Subjects
symbols.namesake ,Mathematical optimization ,education.field_of_study ,Optimization problem ,Local optimum ,Population ,Monte Carlo method ,symbols ,Parallelism (grammar) ,Markov chain Monte Carlo ,Hamming distance ,Parallel tempering ,education - Abstract
We explore the power of parallelism in a stochastic search for global optimum in high-dimensional optimization problems. This search, that often navigates a large solution space through a Markov-Chain Monte Carlo (MCMC) process, needs to make stochastic decisions at every step and needs to escape from local optima. Through parallelism, we are able to survey an entire neighbourhood (all states with Hamming distance of 1) to make efficient moves, use multiple replicas at different temperatures, such as in parallel tempering, or deploy a population of replicas at the same temperature. Once combined, these methods of parallelism can yield 100x to 10,000x speedups.
- Published
- 2021
14. A note on the paper 'Sufficient optimality conditions using convexifactors for optimistic bilevel programming problem'
- Author
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N. Gadhi
- Subjects
0209 industrial biotechnology ,Mathematical optimization ,021103 operations research ,Control and Optimization ,Computer science ,Applied Mathematics ,Strategy and Management ,0211 other engineering and technologies ,02 engineering and technology ,Mathematical proof ,Bilevel optimization ,Atomic and Molecular Physics, and Optics ,020901 industrial engineering & automation ,Work (electrical) ,Bellman equation ,Business and International Management ,Electrical and Electronic Engineering - Abstract
In this work, some reasoning's mistakes in the paper by Kohli (doi:10.3934/jimo.2020114) are highlighted. Furthermore, we correct the flaws, propose a correct formulation of the main result (Theorem 5.1) and give alternative proofs.
- Published
- 2022
15. Special issue "Discrete optimization: Theory, algorithms and new applications".
- Author
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Werner, Frank
- Subjects
MATHEMATICAL optimization ,METAHEURISTIC algorithms ,ONLINE algorithms ,LINEAR matrix inequalities ,ALGORITHMS ,ROBUST stability analysis ,NONLINEAR integral equations - Abstract
This document is an editorial for a special issue of the journal AIMS Mathematics on the topic of discrete optimization. The issue includes 21 papers covering a range of subjects, including molecular trees, network systems, variational inequality problems, scheduling, image restoration, spectral clustering, integral equations, convex functions, graph products, optimization algorithms, air quality prediction, humanitarian planning, inertial methods, neural networks, transportation problems, emotion identification, fixed-point problems, structural engineering design, single machine scheduling, and ensemble learning. The papers present new theoretical results, algorithms, and applications in these areas. The guest editor expresses gratitude to the journal staff and reviewers and hopes that readers will find inspiration for their own research. [Extracted from the article]
- Published
- 2024
- Full Text
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16. 2023 MMOR best paper award.
- Author
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Stein, Oliver
- Subjects
AWARDS ,MATHEMATICAL optimization - Abstract
The MMOR Best Paper Award is given annually to an outstanding article published in the Mathematical Methods of Operations Research journal. The 2023 award was presented to Zhuoyi Xu, Linbin Li, and Yong Xia for their paper on a partial ellipsoidal approximation scheme for nonconvex homogeneous quadratic optimization with quadratic constraints. The authors propose an efficient method to find an approximation solution for this type of optimization problem. Linbin Li is currently pursuing a Ph.D. in applied mathematics, Yong Xia is a full professor and deputy dean at Beihang University, and Zhuoyi Xu is a lecturer at Capital University of Economics and Business. Congratulations to the authors on behalf of the MMOR editorial board. [Extracted from the article]
- Published
- 2024
- Full Text
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17. Bibliometric Survey on Particle Swarm Optimization Algorithms (2001–2021).
- Author
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Ajibade, Samuel-Soma M. and Ojeniyi, Adegoke
- Subjects
MATHEMATICAL optimization ,METAHEURISTIC algorithms ,BIBLIOMETRICS ,CONFERENCE papers ,PROBLEM solving - Abstract
Particle swarm optimization algorithms (PSOA) is a metaheuristic algorithm used to optimize computational problems using candidate solutions or particles based on selected quality measures. Despite the extensive research published, studies that critically examine its recent scientific developments and research impact are lacking. Therefore, the publication trends and research landscape on PSOA research were examined. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and bibliometric analysis techniques were applied to identify and analyze the published documents indexed in Scopus from 2001 to 2021. The published documents on PSOA increased from 8 to 1,717 (21,362.50%) due to the growing applications of PSOA in solving computational problems. "Conference papers" is the most common document type, whereas the most prolific researcher on PSOA is Andries P. Engelbrecht (South Africa). The most active affiliation (Ministry of Education) and funding organization (National Natural Science Foundation) are based in China. The research landscape on PSOA revealed high levels of publications, citations, and collaborations among the top authors, institutions, and countries worldwide. Keywords co-occurrence analysis revealed that "particle swarm optimization (PSO)" occurred more frequently than others. The findings of the study could provide researchers and policymakers with insights into the prospects and challenges of PSOA research relative to similar algorithms in the literature. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
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18. Multi-objective optimization for biomass and lipid production by oleaginous bacteria using vegetable waste as feedstock.
- Author
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Patnaik, Suryakanta, Saravanabhupathy, Sarveshwaran, Singh, Sangeeta, Daverey, Achlesh, and Dutta, Kasturi
- Subjects
FEEDSTOCK ,VEGETABLES ,WASTE paper ,REFUSE containers ,ORGANIC wastes ,BIOMASS production ,MATHEMATICAL optimization ,LIPIDS - Abstract
In this study, pretreated organic wastes such as waste paper cups, cardboard waste, and vegetable waste were screened for the growth and lipid production of oleaginous bacteria DS-7 (isolated from the dairy effluent scum). The pretreated vegetable waste was found to be the best feedstock for biomass and lipid production by the DS-7. Further, process parameters such as inoculation time, substrate concentration (w/v) (amount of pretreated vegetable waste), pH, and inoculum size were optimized using a multi-objective optimization technique to enhance the biomass and lipid productions. The optimization study successfully enhanced the biomass concentration (g/L) and lipid content (%) by 47.9% and 15.84%, respectively in comparison with the unoptimized state. The biomass and lipid productivities were 42% (1.449 g/L/d) and 51% (1.267 g/L/d) greater than unoptimized conditions. The characteristics of the biodiesel obtained from the valorization of vegetable waste were comparable to the standard. Thus, the vegetable waste can be utilized as a potential feedstock for microbial biodiesel production. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
19. A 2-dimensional guillotine cutting stock problem with variable-sized stock for the honeycomb cardboard industry.
- Author
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Terán-Viadero, Paula, Alonso-Ayuso, Antonio, and Javier Martín-Campo, F.
- Subjects
CUTTING stock problem ,LEAD time (Supply chain management) ,HONEYCOMB structures ,STOCKS (Finance) ,MATHEMATICAL optimization ,CARDBOARD - Abstract
This paper introduces novel mathematical optimisation models for the 2-Dimensional guillotine Cutting Stock Problem with Variable-Sized Stock that appears in a Spanish company in the honeycomb cardboard industry. This problem mainly differs from the classical cutting stock problems in the stock, which is considered variable-sized, i.e. we have to decide the panel dimensions, width, and length. This approach is helpful in industries where the stock is produced simultaneously with the cutting process. The stock is then cut into smaller rectangular pieces that must meet the customers' requirements, such as the type of item, dimensions, demands, and technical specifications. Furthermore, in the problem tackled in this paper, the cuts are guillotine, performed side to side. The proposed mathematical models are validated using real data from the company, obtaining results that drastically reduce the produced material and leftovers, reducing operation times and economic costs. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
20. The Intelligent Layout of the Ship Piping System Based on the Optimization Algorithm.
- Author
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Wei, Zhiguo, Wu, Jun, Li, Zhe, Cheng, Shangfang, Yan, Xiaojiang, and Wang, Shunsen
- Subjects
OPTIMIZATION algorithms ,MATHEMATICAL optimization ,PARTICLE swarm optimization ,NAVAL architecture ,GENETIC algorithms ,ELBOW - Abstract
The ship piping layout is one of the essential tasks in the detailed design stage of a ship. Traditional manual expert design has disadvantages such as low efficiency, reliance on experience, and subjective influence. Therefore, this paper systematically proposes an intelligent arrangement method for ships' single, parallel, and branch pipelines. Firstly, the traditional genetic algorithm is improved and combined with the A* algorithm to solve the intelligent arrangement problem of a single pipeline in ships. Then, the parallel pipeline and branch pipeline are split into multiple single pipelines by combining with the connection point strategy to solve the arrangement problem of parallel pipeline and branch pipeline. Finally, the optimized A*-genetic algorithm proposed in this paper is compared with the A* algorithm, particle swarm algorithm, and the labyrinth-genetic algorithm used in previous research through simulation experiments. The results show that the A*-genetic algorithm of this paper is optimal in six indexes, including length, number of elbows, energy value, fitness value, number of optimal solutions, and average number of convergence generations, in the arrangement of the single pipeline. In solving the parallel pipeline and branch pipeline arrangement problems, the all-around performance of this paper's algorithm is better than that of A*-genetic algorithm and maze–genetic algorithm, respectively. The A*-genetic algorithm of this paper considers the quality of pipeline arrangement and the solution's efficiency. It verifies the adaptability and superiority of the algorithm for the intelligent arrangement of various types of pipelines in ship pipelines. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
21. DESIGNING A SEQUENTIAL-MODULAR STEADY-STATE SIMULATOR FOR KRAFT RECOVERY CYCLE EVAPORATIVE SYSTEMS.
- Author
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Vianna Neto, Márcio R., Cardoso, Marcelo, Sermyagina, Ekaterina, Vakkilainen, Esa K., and Oliveira, Eder D.
- Subjects
SULFATE waste liquor ,PAPER industry ,EVAPORATORS ,MATHEMATICAL optimization ,C++ - Abstract
A sequential-modular process simulator was developed for simulating Kraft recovery cycle evaporation plants under steadystate conditions. The simulation engine was written in C++ and has been made freely available to the scientific and technical communities. The engine included subroutines for ordering, partitioning, and tearing flowsheets, as well as for converging torn flowsheet streams. In this paper, these core subroutines are described. Evaporator calculations are based on steam table correlations and black liquor enthalpy correlations described in literature. The numerical method used for converging torn streams in this implementation was the well-known Wegstein Method. Five multiple-effect counter-current evaporator scenarios, ranging from 3 to 7 effects, were used to profile the simulator. The simulator was shown to be robust enough to be used for simulating evaporator arrangements that are typically found in the pulp and paper industry. The robustness of convergence found in the tested scenarios suggests that the simulator could be extended to accommodate more complex systems. The simulator converged quickly to all solutions, suggesting that it may be used for performing optimization of evaporative systems. [ABSTRACT FROM AUTHOR]
- Published
- 2022
22. Voltage Optimization in Active Distribution Networks—Utilizing Analytical and Computational Approaches in High Renewable Energy Penetration Environments.
- Author
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Alshehri, Mohammed and Yang, Jin
- Subjects
OPTIMIZATION algorithms ,RENEWABLE energy sources ,ENERGY storage ,BATTERY storage plants ,VOLTAGE ,SMART power grids ,MATHEMATICAL optimization - Abstract
This review paper synthesizes the recent advancements in voltage regulation techniques for active distribution networks (ADNs), particularly in contexts with high renewable energy source (RES) penetration, using photovoltaics (PVs) as a highlighted example. It covers a comprehensive analysis of various innovative strategies and optimization algorithms aimed at mitigating voltage fluctuations, optimizing network performance, and integrating smart technologies like smart inverters and energy storage systems (ESSs). The review highlights key developments in decentralized control algorithms, multi-objective optimization techniques, and the integration of advanced technologies such as soft open points (SOPs) to enhance grid stability and efficiency. The paper categorizes these strategies into two main types: analytical methods and computational methods. In conclusion, this review underscores the critical need for advanced analytical and computational methods in the voltage regulation of ADNs with high renewable energy penetration levels, highlighting the potential for significant improvements in grid stability and efficiency. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
23. Performance Optimization Techniques in Object Oriented Programming in PHP.
- Author
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Vayadande, Kuldeep, Telsang, Shreyash, Thakare, Manthan, Thigale, Om, Thenge, Aniket, and Tarade, Shreya
- Subjects
OBJECT-oriented programming ,MATHEMATICAL optimization - Abstract
Object-Oriented Programming (OOP) in PHP is gaining traction due to its flexibility and control. This research paper delves into the best practices for optimizing OOP in PHP. The primary focus is on strategies such as designing classes, leveraging inheritance, and implementing caching to expedite processes. The paper also emphasizes the importance of other optimization techniques such as polymorphism, method access optimization, property access optimization, and memory management. Polymorphism allows objects of different classes to be treated as objects of a common superclass, enabling more flexible and dynamic code. Method and property access optimization involve using the most efficient ways to access methods and properties of objects, while memory management ensures that resources are used effectively. Overall, this research provides a comprehensive guide to optimizing PHP OOP, covering a wide range of techniques and strategies. It serves as a valuable resource for PHP developers looking to improve the performance and efficiency of their object-oriented applications. By employing tactics like class design, inheritance, caching, and profiling, developers can harness the full potential of OOP in PHP and build robust, high-performing applications. This paper is a must-read for anyone interested in PHP OOP and its optimization. [ABSTRACT FROM AUTHOR]
- Published
- 2024
24. Optimal operation of flexible interconnected distribution grids based on improved virtual synchronous control techniques.
- Author
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Wang, Zeyi, Liu, Guangzhi, Pang, Dan, Wang, Yao, Yu, Bin, Wang, Zhenhao, Xiao, Huangqing, and Shi, Linjun
- Subjects
POWER resources ,MAXIMUM power point trackers ,MATHEMATICAL optimization ,ELECTRIC transformers - Abstract
With distributed energy sources connected to the distribution grid on a large scale for distributed photovoltaic power randomness, this paper proposes a flexible interconnection system optimization operation strategy. First, the virtual synchronous control technology is improved to improve the DC bus voltage stability; second, it analyzes the system operation mode to judge the output logic of PV and storage units, takes DC bus power balance as the underlying logic, and puts forward the power coordination optimization strategy and fault power supply restoration strategy with full consideration of factors such as the load balance degree of the distribution station area, the economic operation of the main transformer, and the amount of power lost in the faulty station area. It also establishes a multi-objective optimization model to obtain the power commands of each port and achieves the power flexibility mutualization of the flexible interconnected system through the accurate regulation of the soft normally open point (SNOP). Finally, a simulation model of the flexible interconnection system is built using MATLAB/Simulink to verify the effectiveness of the proposed optimization strategy. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
25. Optimisation of the Distribution System Reliability with Shielding and Grounding Design Under Various Soil Resistivities.
- Author
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Jia-Wen Tang, Chin-Leong Wooi, Wen-Shan Tan, Afrouzi, Hadi Nabipour, Halim, Hana Abdull, and Md Arshad@Hashim, Syahrun Nizam
- Subjects
RELIABILITY in engineering ,MATHEMATICAL optimization ,ELECTRIC transients ,LIGHTNING protection ,METAHEURISTIC algorithms ,ICE shelves - Abstract
Lightning strikes can cause equipment damage and power outages, so the distribution system's reliability in withstanding lightning strikes is crucial. This research paper presents a model that aims to optimise the configuration of a lightning protection system (LPS) in the power distribution system and minimise the System Average Interruption Frequency Index (SAIFI), a measure of reliability, and the associated cost investment. The proposed lightning electromagnetic transient model considers LPS factors such as feeder shielding, grounding design, and soil types, which affect critical current, flashover rates, SAIFI, and cost. A metaheuristic algorithm, PSOGSA, is used to obtain the optimal solution. The paper's main contribution is exploring grounding schemes and soil resistivity's impact on SAIFI. Using 4 grounding rods arranged in a straight line under the soil with 10 Ωm resistivity reduces grounding resistance and decreases SAIFI from 3.783 int./yr (no LPS) to 0.146 int./yr. Unshielded LPS has no significant effect on critical current for soil resistivity. Four test cases with different cost investments are considered, and numerical simulations are conducted. Shielded LPSs are more sensitive to grounding topologies and soil resistivities, wherein higher investment, with 10 Ωm soil resistivity, SAIFI decreases the most by 73.34%. In contrast, SAIFIs for 1 kΩm and 10 kΩm soil resistivities show minor decreases compared to SAIFIs with no LPS. The study emphasises the importance of considering soil resistivity and investment cost when selecting the optimal LPS configuration for distribution systems, as well as the significance of LPS selection in reducing interruptions to customers. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
26. A game model based optimisation approach for generalised shared energy storage and integrated energy system trading.
- Author
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Tao, Caixia, Duan, Yunxin, Gao, Fengyang, and Zhang, Jiangang
- Subjects
MATHEMATICAL optimization ,ENERGY industries ,INTEGRATED marketing ,ECONOMIC systems ,ENERGY storage - Abstract
In the context of integrated energy systems, the synergy between generalised energy storage systems and integrated energy systems has significant benefits in dealing with multi-energy coupling and improving the flexibility of energy market transactions, and the characteristics of the multi-principal game in the integrated energy market are becoming more and more obvious, but it is difficult to improve the flexibility of the transactions between "source-load-storage" in a one-way master–slave game structure, and the problem of how to establish an optimisation strategy for the coordination of integrated energy systems and energy storage systems is an urgent issue. How to establish a coordinated optimisation strategy of integrated energy system and energy storage system is an urgent problem. Therefore, this paper proposes a generalised shared energy storage and integrated energy system transaction optimisation method based on a two-stage game model, which improves the flexibility of the system transaction by constructing a two-stage game energy transaction model in which the subject acts as a leader and a gamer. Compared with the current one-way game model that does not consider the game on the energy storage side, the coordinated optimisation method proposed in this paper enables the energy storage side to participate more actively in the scheduling, which improves its revenue by 20.6%, the revenue on the energy-using side by 6.3%, and the overall revenue of the system by 5.4%, and at the same time, the load demand response regulation effect is more obvious, so the energy scheduling strategy proposed in this paper is able to weigh the interests of each subject and increase the overall economic benefits of the system. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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27. Efficient Compiler Design for a Geometric Shape Domain-Specific Language: Emphasizing Abstraction and Optimization Techniques.
- Author
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Gupta, Priya, ManiKiran, Terala, Purushotham, Mailapalli, Suriya, L. Jeya, Venkata, Rasamsetty Naga, and Nanda, Sambhudutta
- Subjects
COMPILERS (Computer programs) ,GEOMETRIC shapes ,MATHEMATICAL optimization ,COMPUTER software development - Abstract
The research paper represents a novel approach to the design and optimization of a compiler for a domain-specific language (DSL) focused on geometric shape creation and manipulation. The primary objective is to develop a compiler capable of generating efficient machine code while offering users a high level of abstraction. The paper begins with an overview of DSLs and compilers, emphasizing their importance in software development. Next, it outlines the specific requirements of the geometric shape DSL and proposes a compiler design that addresses them. This innovative approach considers DSL's unique features, such as shape creation and manipulation, and aims to generate high-quality machine code. The paper also discusses optimization techniques to enhance the generated code's quality and performance, including loop unrolling and instruction scheduling. These optimizations are particularly suited to the DSL, which focuses on geometric shape creation and manipulation and are integral to achieving efficient machine code generation. In conclusion, the paper emphasizes the novelty of this approach to DSL compiler design and anticipates exciting results from testing the compiler developed for the geometric shape DSL. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
28. An overview on human-centred technologies, measurements and optimisation in assembly systems.
- Author
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Slama, Rim, Slama, Ilhem, Tlahig, Houda, Slangen, Pierre, and Ben-Ammar, Oussama
- Subjects
MATHEMATICAL optimization ,MOTION capture (Human mechanics) ,OPERATIONS research ,INDUSTRY 4.0 ,ECONOMIC impact - Abstract
This paper offers an in-depth examination of the ergonomics of human-centred assembly systems in Industry 4.0, where manual tasks remain essential. The use of advanced technologies such as motion capture (MOCAP) and virtual reality (VR) is analysed as ways to enhance system efficiency and improve worker well-being. The paper highlights the importance of optimising assembly system performance while considering both economic and human factors. Metrics to assess ergonomic risk and productivity are discussed based on human-centred technologies, and existing operational research models are explored to analyse how human factors could be considered in optimising system performance. Additionally, the paper explores potential future directions and how they could play a role in Industry 4.0. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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- View/download PDF
29. Optimisation of mooring line parameters for offshore floating structures: A review paper.
- Author
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Ja'e, Idris Ahmed, Osman Ahmed Ali, Montasir, Yenduri, Anurag, Nizamani, Zafarullah, and Nakayama, Akihiko
- Subjects
- *
OFFSHORE structures , *MATHEMATICAL optimization , *MOORING of ships , *EVOLUTIONARY algorithms , *DIFFERENTIAL evolution , *GENETIC algorithms - Abstract
The increased application of Information and Communications Technology in automation and digitization is the driving concept towards the actualization of the Industrial Revolution 4.0. Many aspects of industrial design and operations including offshore engineering have been automated. However, the selection procedure of mooring design parameters including azimuth angle, pretension, diameter, fairlead slope, and mooring radius, which is a critical aspect of mooring system design has remained heavily based on a manual approach despite the availability of sophisticated hydrodynamic analysis software. Up to date, there is no proper review on optimisation techniques that have the potential of automating these procedures. In the past, some of the few available mooring optimisation procedures consider only the mooring lines for the prediction of optimal platform offset without due consideration to the integrity of the risers. Thus, the significance of adopting an integrated riser-mooring design methodology in the optimisation of mooring design variables is discussed in this paper where the integrity of the riser is adequately represented using a Safe Operation (SAFOP) zone polar diagram. We also review the developmental transition from the use of classical to Evolutionary Algorithms (EA) in the optimisation procedure. EA has been acknowledged as a practical alternative for solving mooring optimisation problems. Hence, some of the EA techniques are presented and their computational capabilities explored. In the last part, a concise review of the application of optimisation techniques for mooring optimisation of the different offshore floating platforms is presented based on their capabilities in minimizing platform offset and efficiency in terms of simulation time. So far, EA techniques like the Differential Evolution (DE), variants of Genetic Algorithms (GA) and Particle Swarm Optimisation (PSO) have been used to optimize mooring line design variables. Based on the discussions, the potentials of DE, RegPSO and other variants of PSO can be further explored for better efficiency. • Previous studies addressing differential evolution (DE), genetic algorithm (GE) and particle swarm optimisation (PSO) techniques used for optimisation of mooring parameters have been critically reviewed. • The integrated riser -mooring design methodology is effective in accounting for integrity of riser and mooring systems. • The application of evolutionary algorithms, particularly the variants and hybrids of DE ,PSO and GA, have proven to be efficient optimisation of mooring systems. • Some variants of PSO like the RegPSO have demonstrated improved capability in terms of escaping premature convergence , thereby resulting in better computational efficiency. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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30. Kimberly-Clark streamlines order fulfillment & optimizes transportation
- Author
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McCrea, Bridget
- Subjects
Kimberly-Clark Corp. ,Paper industry ,Transportation ,Consumer goods ,Transportation industry ,Mathematical optimization ,Personal care industry ,Machine learning ,Advertising, marketing and public relations ,Business ,Transportation industry - Abstract
As part of a larger effort to digitize its global supply chain, Kimberly-Clark is putting a combination of machine learning and optimization algorithms to work to optimize its transportation networks-- [...]
- Published
- 2023
31. Adaptive Network Sustainability and Defense Based on Artificial Bees Colony Optimization Algorithm for Nature Inspired Cyber Security.
- Author
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Ganguli, Chirag, Shandilya, Shishir Kumar, Gregus, Michal, and Basystiuk, Oleh
- Subjects
BEES algorithm ,MATHEMATICAL optimization ,INTERNET security ,CYBERTERRORISM ,DENIAL of service attacks ,CYBER physical systems ,DATA packeting ,CONFIDENTIAL communication access control - Abstract
Cyber Defense is becoming a major issue for every organization to keep business continuity intact. The presented paper explores the effectiveness of a meta-heuristic optimization algorithm-Artificial Bees Colony Algorithm (ABC) as an Nature Inspired Cyber Security mechanism to achieve adaptive defense. It experiments on the Denial- Of-Service attack scenarios which involves limiting the traffic flow for each node. Businesses today have adapted their service distribution models to include the use of the Internet, allowing them to effectively manage and interact with their customer data. This shift has created an increased reliance on online services to store vast amounts of confidential customer data, meaning any disruption or outage of these services could be disastrous for the business, leaving them without the knowledge to serve their customers. Adversaries can exploit such an event to gain unauthorized access to the confidential data of the customers. The proposed algorithm utilizes an Adaptive Defense approach to continuously select nodes that could present characteristics of a probable malicious entity. For any changes in network parameters, the cluster of nodes is selected in the prepared solution set as a probable malicious node and the traffic rate with the ratio of packet delivery is managed with respect to the properties of normal nodes to deliver a disaster recovery plan for potential businesses. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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32. Optimization of earthworks planning: a systematic mapping study.
- Author
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Fernandes, Pedro G.P.S., Júnior, Ernesto F. Nobre, and Prata, Bruno de A.
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EARTHWORK ,MIXED integer linear programming ,MATHEMATICAL optimization ,SNOWBALL sampling ,LINEAR programming ,GENETIC algorithms ,BUDGET - Abstract
Copyright of Canadian Journal of Civil Engineering is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
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- 2022
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33. Dynamic Robust Optimization Method Based on Two-Stage Evaluation and Its Application in Optimal Scheduling of Integrated Energy System.
- Author
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Zhou, Bo and Li, Erchao
- Subjects
ROBUST optimization ,OPTIMIZATION algorithms ,MATHEMATICAL optimization ,ENERGY storage ,DYNAMIC testing ,OPERATING costs - Abstract
As an emerging energy allocation method, shared energy storage devices play an important role in modern power systems. At the same time, with the continuous improvement in renewable energy penetration, modern power systems are facing more uncertainties from the source side. Therefore, a robust optimization algorithm that considers both shared energy storage devices and source-side uncertainty is needed. Responding to the above issues, this paper first establishes an optimal model of a regional integrated energy system with shared energy storage. Secondly, the uncertainty problem is transformed into a dynamic optimization problem with time-varying parameters, and a modified robust optimization over time algorithm combined with scenario analysis is proposed to solve such optimization problems. Finally, an optimal scheduling objective function with the lowest operating cost of the system as the optimization objective is established. In the experimental part, this paper first establishes a dynamic benchmark test function to verify the validity of proposed method. Secondly, the multi-mode actual verification of the proposed algorithm is carried out through a regional integrated energy system. The simulation results show that the modified robust optimization over time (ROOT) algorithm could find solutions with better robustness in the same dynamic environment based on the two-stage evaluation strategy. Compared with the existing algorithms, the average fitness and survival time of the robust solution obtained by the modified ROOT algorithm are increased by 94.41% and 179.78%. At the same time, the operating cost of the system is reduced by 11.65% by using the combined optimization scheduling method proposed in this paper. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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- View/download PDF
34. K OUT OF N INTEGRATED RELIABILITY MODEL WITH MULTIPLE STAGE OPTIMIZATION USING FOUR COMPONENTS OF HEURISTIC PROGRAMMING APPROACH.
- Author
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VELAMPUDI, SRINIVASA RAO and KRISHNA, M.
- Subjects
HEURISTIC programming ,RELIABILITY in engineering ,ENGINEERING reliability theory ,MATHEMATICAL optimization ,BOOSTING algorithms ,INTEGERS - Abstract
Integer variables are among the neo-logistic programming issues that most frequently pertain to system reliability improvement. If 'k' out of 'n' elements are present in each technology, then the configuration can be employed with 'k' out of 'n' systems. Only particular objective function structures and restrictions may be used in a heuristic technique to precisely address a dependability optimization problem. As more constraints are placed on it, the more useful it becomes; it is worthless for boosting dependability in a large system. This paper analyzes existing research on integrated reliability models with redundancy and explores system reliability optimization before proposing new recommendations. [ABSTRACT FROM AUTHOR]
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- 2024
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35. On the Integrity of Large-Scale Direct-Drive Wind Turbine Electrical Generator Structures: An Integrated Design Methodology for Optimisation, Considering Thermal Loads and Novel Techniques.
- Author
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Bichan, Magnus, Jaen-Sola, Pablo, Gonzalez-Delgado, Daniel, and Oterkus, Erkan
- Subjects
TURBINE generators ,WIND power ,AUTOMOBILE power trains ,MATHEMATICAL optimization ,FINITE element method ,WIND turbines ,DESIGN techniques ,COMPUTATIONAL fluid dynamics - Abstract
With the rapid expansion of offshore wind capacity worldwide, minimising operation and maintenance requirements is pivotal. Regarded as a low-maintenance alternative to conventional drivetrain systems, direct-drive generators are increasingly commonplace for wind turbines in hard-to-service areas. To facilitate higher torque requirements consequent to low-speed operation, these machines are bulky, greatly increasing nacelle size and mass over their counterparts. This paper therefore details the structural optimisation of the International Energy Agency 15 MW Reference Wind Turbine rotor through iterative Parameter and Topology Optimisation and the inclusion of additional structural members, with consideration to its mechanical, modal, and thermal performances. With temperature found to have a significant impact on the structural integrity of multi-megawatt direct-drive machines, a Computational Fluid Dynamics analysis was carried out to map the temperature of the structure during operation and inform a consequent Finite Element Method analysis. This process, novel to this paper, found that topologically optimised structures outperform parametrically optimised structures thermally and that integrated heatsinks can be employed to further reduce deformation. Lastly, generative design techniques were used to further optimise the structure, reducing its mass, deformation, and maximum stress and expanding its operating envelope. This study reaches several key conclusions, demonstrating that significant mass reductions are achievable through the removal of cylinder wall geometry areas as well as through the implementation of structural supports and iterative parametric and topology optimisation techniques. Through the flexibility it grants, generative design was found to be a powerful tool, delivering further improvements to an already efficient, yet complex design. Heatsinks were found to lower generator structural temperatures, which may yield lower active cooling requirements whilst providing structural support. Lastly, the link between the increased mass and the increased financial and environmental impact of the rotor was confirmed. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
36. A Review of Peer-to-Peer Energy Trading Markets: Enabling Models and Technologies.
- Author
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Islam, Shama Naz
- Subjects
ENERGY industries ,MATHEMATICAL optimization ,MARKETING models ,BIDDING strategies ,PEER-to-peer architecture (Computer networks) ,MACHINE learning - Abstract
This paper presents a detailed review of the existing literature on peer-to-peer (P2P) energy trading considering market architectures, trading strategies, and enabling technologies. P2P energy trading enables individual users in the electricity network to act as sellers or buyers and trade energy among each other. To facilitate the discussion on different aspects of P2P energy trading, this paper focuses on P2P market mechanisms, relevant bidding strategies, and auction models. In addition, to solve the energy management problems associated with P2P energy trading, this paper investigates widely used solution methods such as game-theoretic models, mathematical optimisation, as well as more recent machine learning techniques and evaluates them in a critical manner. The outcomes of this investigation along with the identification of the challenges and limitations will allow researchers to find suitable P2P energy trading mechanisms based on different market contexts. Moreover, the discussions on potential future research directions are expected to improve the effectiveness of P2P energy trading technologies. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
37. Echo State Network Optimization: A Systematic Literature Review.
- Author
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Soltani, Rebh, Benmohamed, Emna, and Ltifi, Hela
- Subjects
PARTICLE swarm optimization ,EVIDENCE gaps ,MATHEMATICAL optimization - Abstract
In the recent years, numerous studies have demonstrated the importance and efficiency of reservoir computing (RC) approaches. The choice of parameters and architecture in reservoir computing, on the other hand, frequently leads to an optimization task. This paper attempts to present an overview of the related work on echo state network (ESN) and deep echo state network (DeepESN) optimization and to collect research papers through a systematic literature review (SLR). This review covers 129 items published from 2004 to 2022 that are concerned with the issue of our focus. The collected papers are selected, analysed and discussed. The results indicate that there are two techniques of parameters optimization (bio-inspired and non-bio-inspired methods) have been extensively used for various reasons. But Different models employ bio-inspired methods for optimizing in a variety of fields. The potential use of particle swarm optimization (PSO) has also been noted. A significant portion of the research done in this field focuses on the study of reservoirs and how they behave in relation to their unique qualities. In order to test reservoirs with varied parameters, topologies, or training techniques, NARMA, the Mackey glass, and Lorenz time-series prediction dataset are the most commonly employed in the literature. This review debate diverse point of view about ESN's hyper-parameter optimization, metrics, time series benchmarks, real word applications, evaluation measures, and bio-inspired and non-bio-inspired techniques, this paper identifies and explores a number of research gaps. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
38. Editorial for the Special Issue on Advanced Manufacturing Technology and Systems, 2nd Edition.
- Author
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Xing, Youqiang, Hao, Xiuqiang, and Duan, Duanzhi
- Subjects
MANUFACTURING processes ,LIBRARY users ,MATHEMATICAL optimization ,LIBRARY resources ,ELECTRONIC journals ,MICROELECTROMECHANICAL systems - Abstract
This document is an editorial for a special issue of the journal Micromachines on Advanced Manufacturing Technology and Systems (AMTS). The special issue contains 32 original papers covering various research fields, including manufacturing technology, structure design, system optimization, and precision measurement. Each paper focuses on a specific aspect of AMTS, such as the performance of coated tools, fabrication processes, optimization strategies, and measurement techniques. The editorial provides a comprehensive overview of the topics covered in the special issue, making it a valuable resource for library patrons conducting research in this field. The document also includes an acknowledgment section, expressing gratitude to the contributors, reviewers, and assistant editors for their efforts in improving the quality of the submitted papers. [Extracted from the article]
- Published
- 2023
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39. Intelligent fault diagnosis algorithm of rolling bearing based on optimization algorithm fusion convolutional neural network.
- Author
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Wang, Qiushi, Sun, Zhicheng, Zhu, Yueming, Song, Chunhe, and Li, Dong
- Subjects
CONVOLUTIONAL neural networks ,FAULT diagnosis ,ROLLER bearings ,MATHEMATICAL optimization ,DIFFERENTIAL evolution - Abstract
As an essential component of mechanical equipment, the fault diagnosis of rolling bearings may not only guarantee the systematic operation of the equipment, but also minimize any financial losses caused by equipment shutdowns. Fault diagnosis algorithms based on convolutional neural networks (CNN) have been widely used. However, traditional CNNs have limited feature representation capabilities, thereby making it challenging to determine their hyperparameters. This paper proposes a fault diagnosis method that combines a 1D-CNN with an attention mechanism and hyperparameter optimization to overcome the aforementioned limitations; this method improves the search speed for optimal hyperparameters of CNN models, improves the diagnostic accuracy, and enhances the representation of fault feature information in CNNs. First, the 1D-CNN is improved by combining it with an attention mechanism to enhance the fault feature information. Second, a swarm intelligence algorithm based on Differential Evolution (DE) and Grey Wolf Optimization (GWO) is proposed, which not only improves the convergence accuracy, but also increases the search efficiency. Finally, the improved 1D-CNN alongside hyperparameters optimization are used to diagnose the faults of rolling bearings. By using the Case Western Reserve University (CWRU) and Jiangnan University (JNU) datasets, when compared to other common diagnosis models, the results demonstrate the usefulness and dependability of the DE-GWO-CNN algorithm in fault diagnosis applications by demonstrating the increased diagnostic accuracy and superior anti-noise capabilities of the proposed method. The fault diagnosis methodology presented in this paper can accurately identify faults and provide dependable fault classification, thereby assisting technicians in promptly resolving faults and minimizing equipment failures and operational instabilities. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
40. Comprehensive review of solar radiation modeling based on artificial intelligence and optimization techniques: future concerns and considerations.
- Author
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Attar, Nasrin Fathollahzadeh, Sattari, Mohammad Taghi, Prasad, Ramendra, and Apaydin, Halit
- Subjects
SOLAR radiation ,ARTIFICIAL intelligence ,MATHEMATICAL optimization ,RENEWABLE energy sources ,SOLAR energy ,FEATURE selection - Abstract
An alternative energy source such as solar is one of the most important renewable resources. A reliable solar radiation prediction is essential for various applications in agriculture, industry, transport, and the environment because they reduce greenhouse gases and are environmentally friendly. Solar radiation data series have embedded fluctuations and noise signals due to complexity, stochasticity, non-stationarity, and nonlinearity with uncertain and time-varying nature. Aside from being highly nonlinear, solar radiation is highly influenced by the environment and environmental parameters such as air temperature, cloud cover, surface reflectivity, and aerosols. In addition, the spatial measurements of these variables are not readily available. To tackle these challenges, it is necessary to consider data preprocessing techniques and to develop and test precise solar radiation predicting models at different forecast horizons. There is, however, controversy regarding the performance of such models in various studies. Comparisons are not conducted systematically among the different studies. Using a critical literature review, the authors hope to answer these questions and believe that further investigation of solar radiation can benefit researchers and practitioners alike. This study presents a comprehensive evaluation of solar radiation modeling using artificial intelligence in the last 15 years and provides a novel detailed analysis of the available models. The studies conducted in different climates of the world that were published in distinguished journals were considered (i.e., 90 papers in total) for this purpose. Newly discovered procedures for optimizing forecasts, data cleaning, feature selection, classification methods, and stand-alone or hybrid data-driven models for solar radiation prediction and modeling were evaluated. The results strikingly showed that the most used artificial intelligence methods were artificial neural network, adaptive neuro-fuzzy inference system, and decision tree family of models. In addition, the extreme learning machine, support vector machine, and particle swarm optimization were the most used optimization techniques in solar radiation modeling. In terms of forecast horizons, the most common forecast horizon found in papers was on the daily scale (51% of studies), followed by the hourly scale (26%), and the least common was the monthly scale (18%). Based on the regional studies, the highest number of solar radiation papers originated from Asia, with Europe in second place and African countries in third place. An increasing trend in the number of papers from 2011 to 2015 was noted, and the second peak started from 2018 till the present. Under each section, a summary of findings is provided. The paper concludes with future thoughts and directions on solar radiation modeling. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
41. Performance Analysis for 3D Reconstruction Objects in Meshroom and Agisoft—A Comparative Study.
- Author
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Enesi, Indrit and Kuqi, Anduel
- Subjects
SPARE parts ,FREEWARE (Computer software) ,GEOMETRIC shapes ,THREE-dimensional printing ,MATHEMATICAL optimization - Abstract
3D reconstruction of objects is with interest nowadays, mainly in production industry. The main challenge of them is accuracy and processing time, especially for small and detailed objects. The field of photogrammetry realizes the 3D reconstruction of objects through 2D photos. Different software, free or non-free exists, providing different quality and performance. Accurate 3D reconstruction is important in cloning objects, especially in the industry of spare parts or in the production of prostheses in medicine, etc. Determining accurately the sizes of the object, especially those with complex geometric shapes is very important in the 3D printing process. The purpose of this paper is the analysis of the performance of 3D reconstruction in terms of accuracy for objects of different sizes regarding the number of its photos and the time evaluation of this process. The 3D reconstruction will be performed by free software Meshroom, measurement will be done in MeshLab and non-free software Agisoft. Experimental results show that quality and performance of 3D reconstruction depends on the number of photos of the object, concluding in finding the optimal balance between these parameters. By comparing obtained results from MeshRoom and Meshlag versus Agisoft, it is claimed that Agisoft performs better than MeshRoom. It offers more optimization techniques, reduces processing time, more visual quality in the reconstructed 3D object as well as more accuracy in measurement. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
42. A new design of positive functional H∞ filters for positive linear time-delay systems.
- Author
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Ezzine, Montassar, Darouach, Mohamed, Souley Ali, Harouna, and Messaoud, Hassani
- Subjects
POSITIVE systems ,SYLVESTER matrix equations ,LINEAR systems ,MATHEMATICAL optimization ,SYSTEM dynamics - Abstract
This paper solves the problem of designing positive functional $ H_{\infty } $ H ∞ filters for positive linear time-delay systems. In fact, we propose a new positive reduced order $ H_{\infty } $ H ∞ filter for positive linear constant state time-delay systems for which the states remain in the nonnegative orthant of the state space, subject to disturbances and unknown inputs. This paper is a first attempt to design positive unknown inputs functional $ H_{\infty } $ H ∞ filter for such positive linear delayed systems. The proposed approach is based on the positivity of an augmented system composed of dynamics of both considered system and proposed filter, on the unbiasedness of the estimation error by the resolution of Sylvester equation and also on Lyapunov-Krasovskii stability theory; then conditions for the establishment of such filters are formulated in terms of an optimization problem. An algorithm that summarizes the different steps of the proposed positive functional $ H_{\infty } $ H ∞ filter design is given. Finally, numerical example and simulation results are given to illustrate the effectiveness of the proposed design method. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
43. Hybrid Tabu-Grey wolf optimizer algorithm for enhancing fresh cold-chain logistics distribution.
- Author
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Zhang, Hao, Yan, Jianing, and Wang, Liling
- Subjects
METAHEURISTIC algorithms ,GREY Wolf Optimizer algorithm ,PARTICLE swarm optimization ,HEURISTIC algorithms ,MATHEMATICAL optimization - Abstract
The increasing public demand for fresh products has catalyzed the requirement for cold chain logistics distribution systems. However, challenges such as temperature control and delivery delays have led a significant product loss and increased costs. To improve the current situation, a novel approach to optimize cold chain logistics distribution for fresh products will be presented in the paper, utilizing a hybrid Tabu-Grey wolf optimizer (TGWO) algorithm. The proposed hybrid approach combines Tabu search (TS) and Grey wolf optimizer (GWO), employing TS for exploration and GWO for exploitation, aiming to minimize distribution costs in total and establish efficient vehicle scheduling schemes considering various constraints. The effectiveness of the TGWO algorithm is demonstrated through experiments and case studies compared to other heuristic algorithms. Comparative analysis against traditional optimization methods, including Particle swarm optimization (PSO), Whale optimization algorithm (WOA), and original GWO, highlights its superior efficiency and solution quality. This study contributes theories by demonstrating the efficacy of hybrid optimization techniques in complex supply chain networks and dynamic market environments. The practical implication lies in the implementation of TGWO to bolster distribution efficiency, cost reduction, and product quality maintenance throughout the logistics process, offering valuable insights for operational and strategic improvements by decision-makers. However, the study has limitations in generalizability and assumptions, suggesting future research areas including exploring new search operators, applying additional parameters, and using the algorithm in diverse real-life scenarios to improve its effectiveness and applicability. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
44. Model for dimensioning borehole heat exchanger applied to mixed-integer-linear-problem (MILP) energy system optimization.
- Author
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Blanke, Tobias, Born, Holger, Döring, Bernd, Göttsche, Joachim, Herrmann, Ulf, Frisch, Jérôme, and van Treeck, Christoph
- Subjects
HEAT exchangers ,GEOTHERMAL resources ,MATHEMATICAL optimization ,LINEAR equations ,INTEGERS ,MIXED integer linear programming - Abstract
This paper introduces three novel approaches to size geothermal energy piles in a MILP, offering fresh perspectives and potential solutions. The research overlooks MILP models that incorporate the sizing of a geothermal borefield. Therefore, this paper presents a new model utilizing a g-function model to regulate the power limits. Geothermal energy is an essential renewable source, particularly for heating and cooling. Complex energy systems, with their diverse sources of heating and cooling and intricate interactions, are crucial for a climate-neutral energy system. This work significantly contributes to the integration of geothermal energy as a vital energy source into the modelling of such complex systems. Borehole heat exchangers help generate heat in low-temperature energy systems. However, optimizing these exchangers using mixed-integer-linear programming (MILP), which only allows for linear equations, is complex. The current research only uses R-C, reservoir, or g-function models for pre-sized borefields. As a result, borehole heat exchangers are often represented by linear factors such as 50 W/m for extraction or injection limits. A breakthrough in the accuracy of borehole heat exchanger sizing has been achieved with the development of a new model, which has been rigorously compared to two simpler models. The geothermal system was configured for three energy systems with varying ground and bore field parameters. The results were then compared with existing geothermal system tools. The new model provides more accurate depth sizing with an error of less than 5 % compared to simpler models with an error higher than 50 %, although it requires more calculation time. The new model can lead to more accurate borefield sizing in MILP applications to optimize energy systems. This new model is especially beneficial for large-scale projects that are highly dependent on borefield size. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
45. Application of Electrical Protection on Subsea Electrically Trace Heated Pipe-in-Pipe Line.
- Author
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Jez, Radoslaw, Lazarczyk, Michal, Ejma-Multanski, Jakub, Kowalik, Ryszard, Januszewski, Marcin, Kurek, Karol, Nogal, Lukasz, Szreder, Radosław, and Szewczyk, Marcin
- Subjects
POWER system simulation ,PHENOMENOLOGICAL theory (Physics) ,MATHEMATICAL optimization ,SIMULATION methods & models - Abstract
The deployment of Electrically Trace Heated Pipe-in-Pipe (ETH-PiP) brings the challenges of reliable protection selection and setting. This paper presents a study of relays and protection function optimization for ETH-PiP systems. The study is based on the developed simulation model of a typical ETH-PiP system. The paper presents simulation studies of physical phenomena occurring during electrical disturbances in the ETH-PiP system and offers detailed analyses applicable to system protection, including detection of disturbances, location, and elimination. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
46. Production optimization with the maintenance of environmental sustainability based on multi-criteria decision analysis.
- Author
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Khan, Debdip and Gupta, Ranjan Kumar
- Subjects
MULTIPLE criteria decision making ,SUSTAINABILITY ,DECISION making ,MATHEMATICAL optimization ,SOCIAL development ,CORPORATE sustainability - Abstract
Over the last few decades, researches related to the impact of production and industrial manufacturing on environmental sustainability, coupled with multi-dimensional multi-criteria decision analysis and performance evaluation has consistently gained importance. However, no significant work in which an effort to optimize the total production process with the consideration of the positive and negative impacts of each input and output on Environmental sustainability has been noticed. The main aim of our paper is to address this gap. In this paper, an effort has been made to develop a realistic optimization model wherein a manufacturing firm has been considered to function with several decision-making units taking into account the effects of factors like profit, employment generation, social development, environmental pollution and sustainability. The various inputs employed and outputs produced by the firm are responsible for having negative impacts on the environment, besides creative value generation. With due consideration to both these values instead of mere profit, the model determines and explores the firm's decision considering different objectives. The optimization problem has been solved by a GA developed by us and demonstrated with numerical examples. The solutions of the numerical examples point towards some interesting revelations and indicate some prospective future research directions which contributes to this field of research. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
47. Software-Defined Wide Area Networks (SD-WANs): A Survey.
- Author
-
Fu, Chunle, Wang, Bailing, and Wang, Wei
- Subjects
ENGINEERING services ,COMPUTER systems ,TRAFFIC engineering ,MATHEMATICAL optimization ,SOFTWARE-defined networking ,WIDE area networks - Abstract
SD-WANs are an innovative software-defined network (SDN) technology used to reinvent networks, services, and applications in wide area network (WANs). The development of SD-WANs ranges from network optimization in the past to service provision platforms at present and distributed computing systems in the future. The existing surveys on SD-WANs are fragmented, covering specific problems only, and are not comprehensive with detailed research directions. This paper seeks to provide a systematic survey on SD-WANs by introducing major research directions and stating specific problems. Therefore, four major research directions related to traffic engineering, network optimization and systems, service orchestration, and the security issues of SD-WANs are sequentially introduced, along with detailed statements relating to specific problems and the classification of state-of-the-art research. Finally, the trends and challenges regarding SD-WANs are summarized and our future work is described. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
48. Optimisation of a multilevel logistics network for prepositioned warehouses under an omni-channel retail model.
- Author
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Li, Chenxing and Shi, Xianliang
- Subjects
RETAIL industry ,COVID-19 pandemic ,AGRICULTURAL processing ,WAREHOUSES ,MATHEMATICAL optimization - Abstract
A new omni-channel retailing mode, prepositioned warehouses, which developed rapidly in China during the COVID-19 pandemic, was introduced, and a three-level logistics network optimisation model for agricultural products was presented. This study takes into account the characteristics of the omni-channel retail model, which combines the two delivery methods of vehicle delivery and consumer in-store purchase, adds the freshness penalty incurred by fresh agricultural products in the storage process of the prepositioned warehouse, and establishes a mathematical optimisation model of the three-stage logistics network of the prepositioned warehouse that meets the characteristics of omni-channel retailing on the basis of the classical EOQ inventory model. In this work, the shortest delivery time and the smallest total cost are set as the optimisation objectives, and the multi-objective problem is transformed into a single objective through normalisation and linear weighting methods to obtain a mixed-integer optimisation model. This paper solves the problems of site selection for prepositioned warehouses, merchandise replenishment strategies, and optimisation of delivery routes based on data from real cases. Additionally, through sensitivity analysis, the management inspiration of the enterprise is obtained. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
49. Optimizing storage on fog computing edge servers: A recent algorithm design with minimal interference.
- Author
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Zhao, Xumin, Xie, Guojie, Luo, Yi, Chen, Jingyuan, Liu, Fenghua, and Bai, HongPeng
- Subjects
OPTIMIZATION algorithms ,MINIMAL design ,MATHEMATICAL optimization ,CLOUD storage ,STORAGE ,DATA management - Abstract
The burgeoning field of fog computing introduces a transformative computing paradigm with extensive applications across diverse sectors. At the heart of this paradigm lies the pivotal role of edge servers, which are entrusted with critical computing and storage functions. The optimization of these servers' storage capacities emerges as a crucial factor in augmenting the efficacy of fog computing infrastructures. This paper presents a novel storage optimization algorithm, dubbed LIRU (Low Interference Recently Used), which synthesizes the strengths of the LIRS (Low Interference Recency Set) and LRU (Least Recently Used) replacement algorithms. Set against the backdrop of constrained storage resources, this research endeavours to formulate an algorithm that optimizes storage space utilization, elevates data access efficiency, and diminishes access latencies. The investigation initiates a comprehensive analysis of the storage resources available on edge servers, pinpointing the essential considerations for optimization algorithms: storage resource utilization and data access frequency. The study then constructs an optimization model that harmonizes data frequency with cache capacity, employing optimization theory to discern the optimal solution for storage maximization. Subsequent experimental validations of the LIRU algorithm underscore its superiority over conventional replacement algorithms, showcasing significant improvements in storage utilization, data access efficiency, and reduced access delays. Notably, the LIRU algorithm registers a 5% increment in one-hop hit ratio relative to the LFU algorithm, a 66% enhancement over the LRU algorithm, and a 14% elevation in system hit ratio against the LRU algorithm. Moreover, it curtails the average system response time by 2.4% and 16.5% compared to the LRU and LFU algorithms, respectively, particularly in scenarios involving large cache sizes. This research not only sheds light on the intricacies of edge server storage optimization but also significantly propels the performance and efficiency of the broader fog computing ecosystem. Through these insights, the study contributes a valuable framework for enhancing data management strategies within fog computing architectures, marking a noteworthy advancement in the field. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
50. Existence and convergence of fixed points for noncyclic φ-contractions.
- Author
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Safari-Hafshejani, Akram
- Subjects
FIXED point theory ,BANACH spaces ,MATHEMATICS ,LAGRANGE equations ,MATHEMATICAL optimization - Abstract
In the paper, we introduce a new class of noncyclic φ-contractions as a generalization of the class of noncyclic contractions which was first introduced in the paper [R. Esp'ınola, M. Gabeleh, On the structure of minimal sets of relatively nonexpansive mappings, Numerical Functional Analysis and Optimization 34 (8), 845-860, 2013] and study the existence, uniqueness and convergence of a fixed point for such class of noncyclic mapping in the framework of uniformly convex Banach spaces. We obtain existence results of the best proximity points for cyclic φ-contractions as a consequence of our main theorems. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
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