Multi-criteria Optimization Method Research Articles

Analysis of Influential Parameters in the Dynamic Loading and Stability of the Swing Drive in Hydraulic Excavators

The proper design and configuration of the swing drive mechanism of a hydraulic excavator are crucial to improve energy consumption and efficiency and ensure operational stability. This paper analyzes the influence of the relationship between the parameters of a hydraulic motor and a reducer, which form the integrated transmission of a swing drive, the dynamic characteristics of a hydraulic excavator on loading, and the dynamic stability of the drive. The analysis deals with an excavator model that has the same parameters of the kinematic chain members, the same parameters of the upper structure drive mechanisms, and two variants of the swing drive that, with different integrated transmission parameters, provide the upper structure with the identical number of revolutions and equal rotating moment. One swing drive variant possesses an integrated transmission with a hydraulic motor with a low specific flow and a reducer with a high transmission ratio, while the other drive variant has the opposite parameters. Understanding this relationship is essential for optimizing the design of excavators to achieve better performance and dynamic stability under varying operational conditions. As an example, this paper provides the analysis results regarding the influence of the relationship between the parameters of the integrated transmission hydraulic motor and reducer on the loading and dynamic stability of the swing drive in a tracked hydraulic excavator of 100,000 kg in mass and 4.4 m3 in loading bucket volume, as obtained from the developed dynamic mathematical models of the excavator using the MSC ADAMS program. The results indicate that the dynamic loads on the swing drive’s axial bearing are higher in the variant with a low-specific-flow motor and high transmission ratio reducer during the acceleration and deceleration phases. However, this configuration demonstrated better dynamic stability, with lower oscillation amplitudes and shorter damping times compared to the variant with a high-flow motor and low transmission ratio. Those findings provide valuable criteria for the optimal synthesis of swing drive mechanisms in large hydraulic excavators using multi-criteria optimization methods.

Practical Approach to Studying Evolutionary Methods for Setting Weight Coefficients of Artificial Neural Networks

The article describes the problems of developing neurocontrollers for controlling dynamic objects, including the complexity of forming training data sets. It is indicated that one of the known methods for training an artificial neural network controlling an object is the neuroevolutionary approach, which involves using a genetic algorithm to adjust the synaptic weighting coefficients of an artificial neural network. The idea of using a means of demonstrating the evolutionary approach to adjusting the weighting coefficients of an artificial neural network for practical training of students in the basics of the neuroevolutionary approach is proposed. Software has been developed to demonstrate the neuroevolutionary approach using the example of the evolution of an artificial neural network of a given structure intended to control a simplified computer model of an autonomous vehicle. A method for resolving the problem of stagnation when using the evolutionary approach to training an artificial neural network is described. Options for using the developed software in teaching students the basics of artificial intelligence technologies and evolutionary methods of multicriteria optimization are proposed.

Methods of multi-criteria optimization of technological objects: a systematic review of scientific publications for the period 2013–2023

The article presents a systematic review of scientific articles devoted to applications of multi-criteria optimization methods, published in open sources in 2013-2023, conducted in accordance with the PRISMA recommendations. The main optimization methods with respect to a set of conflicting objective functions, such as energy efficiency, accuracy of achieving final states, economic feasibility, reliability of operation, compliance with environmental standards, etc. are considered. Particular attention is paid to the theoretical foundations and practical applications of these methods aimed at increasing the efficiency of technological processes and improving the quality of decisions. The main objective of the review is to analyze the current state of research in this area, to identify trends and limitations in the use of multi-criteria methods for optimization of specific technological processes and objects. The study showed that, despite significant progress in the development of the theoretical foundations of multi-criteria optimization, the number of works aimed at applying these methods to real technological problems remains limited. The article emphasizes the importance of further research and development aimed at adapting optimization methods to the specific features of technological processes. This review aims to provide a deeper understanding of current trends and issues related to the application of multi-objective optimization methods to improve technological processes, thereby contributing to the development of research in this promising area.

Methods of Multi-Criteria Optimization of Technological Processes in a Fuzzy Environment Based on the Simplex Method and the Theory of Fuzzy Sets

Many modern technological objects in practice are characterized by the uncertainty of the initial information necessary for their management. Recently, one of the pressing scientific and practical problems is the development of new optimization methods for controlling the operating modes of such objects in a fuzzy environment. In this regard, the objective of this study is to develop methods of multi-criteria optimization in a fuzzy environment by modifying the simplex method and various optimality principles based on fuzzy mathematics methods. The methodology of the proposed study is based on a hybrid approach, which consists of the integrated use and modification of simplex methods and optimization methods with various optimality principles for working in a fuzzy environment. The main results are as follows: a simplex method of multi-criteria optimization of immeasurable criteria (here, we are talking about the impossibility of physical measurements of criteria, the values of which are estimated by decision maker); a theorem on the convergence of the solution sequence obtained using the proposed method to the minimum value of the criteria; a heuristic method based on a modification for fuzziness and a combination of the maximin and Pareto optimality principles, which allows effectively solving multi-criteria optimization problems in a fuzzy environment. The heuristic method proposed will be used to solve a real production problem—optimization of the technological process of benzene production.

Nature's Load-Bearing Design Principles and Their Application in Engineering: A Review.

Biological structures optimized through natural selection provide valuable insights for engineering load-bearing components. This paper reviews six key strategies evolved in nature for efficient mechanical load handling: hierarchically structured composites, cellular structures, functional gradients, hard shell-soft core architectures, form follows function, and robust geometric shapes. The paper also discusses recent research that applies these strategies to engineering design, demonstrating their effectiveness in advancing technical solutions. The challenges of translating nature's designs into engineering applications are addressed, with a focus on how advancements in computational methods, particularly artificial intelligence, are accelerating this process. The need for further development in innovative material characterization techniques, efficient modeling approaches for heterogeneous media, multi-criteria structural optimization methods, and advanced manufacturing techniques capable of achieving enhanced control across multiple scales is underscored. By highlighting nature's holistic approach to designing functional components, this paper advocates for adopting a similarly comprehensive methodology in engineering practices to shape the next generation of load-bearing technical components.

Renewable Energy Technology Selection for Hotel Buildings: A Systematic Approach Based on AHP and VIKOR Methods

This study provides an assessment of renewable energy technology utilization in hotel buildings, which are significant structures in terms of energy consumption. The aim of the study is to determine suitable renewable energy technologies (RETs) for hotel buildings by defining criteria for evaluating RETs, assessing the relative importance of these criteria, and proposing a multi-criteria decision-making framework to solve the problem of selecting the most appropriate RETs during the design stage. The alternatives for RETs and the criteria for their evaluation are gathered through a literature review and expert consultations. Eight fundamental RETs used in hotel buildings (such as heat pumps, solar panels, biomass boilers, etc.) are examined, and nine selection criteria are analyzed. According to the weights determined by the Analytic Hierarchy Process (AHP) method, the initial investment cost is the most influential decision criterion, with a weight of 0.314. As a result of applying the AHP and VIKOR (Multi-Criteria Optimization and Compromise Solution) methods for technology selection, photovoltaic panels emerge as the top-ranked choice. This comprehensive evaluation provides stakeholders in the building production process of hotel buildings with detailed analyses and multi-criteria decision-making methods for selecting RETs.

An experimental investigation on copper square electrode wear in electric discharge machining of Hastelloy B2

Hastelloy B2 is a high-performance nickel-molybdenum alloy and has been used in micro reactor, pump, pipe, and corrosion-resistant equipment. Square holes are required in the above application components. Although square holes are easily produced by spending more electrodes wear in Electrical Discharge Machining (EDM). Moreover, the square hole with small electrode wear achieved is a challenging task in thermal machining. Hence, in this work, the effects of EDM process parameters on electrode taper angle, electrode radius, electrode wear length and cutting time of Hastelloy B2 are studied. Taguchi based VišekriterijumskoKompromisnoRangiranje (VIKOR) method is used to find the optimum process parameters and compared with Taguchi based Grey Relational Analysis (GRA) method for validation. The results showed that current and pulse duration greatly affects the electrode wear out surface and edges. The square electrodes with sharp edges and surfaces are fully transformed into hemispherical shapes at electrode ends due to an unstable spark with diffusion of heat. Also, the VIKOR method provides an alternative multi-criteria optimization method that enhances the process performance over the grey relational analysis due to comparability, uniqueness, assessment and prediction.

Analysis of the Multi Objective Optimization by Ratio Analysis (MOORA) Method in Determining Pilot Areas at PT. XYZ

This research analyzes the application of the Multi Objective Optimization by Ratio Analysis (MOORA) method model in determining the Pilot Area at PT XYZ. This method is used to evaluate various performance criteria, including customer satisfaction, productivity, service quality, and operational efficiency. Currently, the Pilot Area assessment and selection process at PT XYZ is still done manually, which causes a lack of accuracy and efficiency. MOORA was chosen for its ability to handle multi-criteria decision-making problems more systematically and objectively. The analysis results showed that Alternative Area 7 obtained the highest final score of 0.39, placing it as an area with superior performance. The application of MOORA is proven to improve accuracy and efficiency in the Pilot Area determination process, providing a more objective basis for decision-making. By using MOORA, PT XYZ can evaluate area performance more comprehensively and accountably. This research recommends that PT XYZ implement the MOORA method thoroughly and conduct periodic evaluations of the methods used. For theory development, PT XYZ can add specific evaluation criteria according to company needs. The implementation of these suggestions is expected to improve the quality of service and competitiveness of PT XYZ in the global market. Further research is expected to compare MOORA with other methods to strengthen the validity of the results. Thus, this research not only provides a practical contribution to PT XYZ but also adds academic insight into the application of multi-criteria optimization methods in the context of performance management and service improvement.

Multicriteria optimization of radiation therapy: Towards empowerment and standardization of reverse planning for head and neck squamous cell carcinoma

PurposeThe purpose of this study was to assess if multicriteria optimization could limit interoperator variability in radiation therapy planning and assess if this method could contribute to target volume coverage and sparing of organ at risk for intensity-modulated curative radiation therapy of head and neck cancers. Material and methodsWe performed a retrospective analysis on 20 patients treated for an oropharyngeal or oral cavity squamous cell carcinoma. We carried out a comparative dosimetric study of manual plans produced with Precision® software, compared with the plans proposed using the multicriteria optimization method (RayStation®). We assessed interoperator reproducibility on the first six patients, and dosimetric contribution in sparing organs at risk using the multicriteria optimization method. ResultsMedian age was 69 years, most lesions were oropharyngeal carcinoma (65%), and 35% lesions were stage T3. First, we obtained a high degree of similarity between the four operator measurements for each patient at the level of each organ. Intraclass correlation coefficients were greater than 0.85. Second, we observed a significant dosimetric benefit for contralateral parotid gland, homolateral and contralateral masseter muscles, homolateral and contralateral pterygoid muscles and for the larynx (P<0.05). For the contralateral parotid gland, the mean dose difference between the multicriteria optimization and manual plans was −2.0Gy (P=0.01). Regarding the larynx, the mean dose difference between the two plans was −4.6Gy (P<0.001). ConclusionMulticriteria optimization is a reproducible technique and faster than manual optimization. It allows dosimetric advantages on organs at risk, especially for those not usually taken into consideration in manual dosimetry. This may lead to improved quality of life.

The need for renewal of the real estate cadastre on the territory of Vojvodina, Republic of Serbia

The aim of this paper is to perform ranking of five cadastral municipalities in the territory of the administrative municipality of Pancevo, in which land consolidation was not carried out, in order to determine the sequence for carrying out work on the renewal of the geodetic survey. The authors used the VIKOR method, as one of the multi-criteria optimization methods. The list of eight criterion functions (fi) and six sub-criteria (kij) was adopted for the multi-criteria optimization of the renewal of real estate cadastre in the research area. The multi-criteria ranking list of cadastral municipalities as alternative solutions, and the proposal of a compromise solution were determined for four different combinations of weights ωi, by which different relative importance of criterion functions is expressed. The obtained results, in a form of ranking lists for every combination of weights, allowed creating the hierarchy of the urgency of the commencement of works on the renewal of real estate cadastre. One of the problems in Serbian cadastre is that in all cadastral municipalities on the territory of Vojvodina, in which land consolidation has not been carried out, cadastral plans of the "old" graphical survey are still in use. The fact that real estate cadastre is still dealing with graphical survey data points to the need for the renewal of the real estate cadastre in the cadastral municipalities in which land consolidation was not carried out. The renewed, which would also mean contemporary and current, real estate cadastre represents a good foundation for making well-informed decisions relating to nature conservation, resolution of water-related issues, or enhancement of agricultural practices.

Reinforcing resilience for integrated design of green and grey infrastructure with real-time control rules by considering system failures

The mutual benefits of real-time control and green and grey infrastructure for urban drainage system (UDS) renovations have drawn great attention. However, risks emerged due to equipment and structural failures, and no studies considered such failures while optimizing the renovation scheme. To address this issue, this study proposed a multi-criteria optimization method for the integrated design of green and grey infrastructure with real-time control rules, where the economic cost and system performance under normal and exceptional conditions were optimized simultaneously. Failure probabilities of equipment and structure were quantified using homogeneous Poisson process models, and failure losses were estimated with the aid of a machine learning-based surrogate model. This approach was tested with a combined UDS in China. Results indicate that: (1) More investment does not necessarily increase system resilience to failures. Equipment and structural failures can significantly lower the effectiveness of grey infrastructure and real-time control. Therefore, solutions with more investments in grey infrastructure, which indicate higher costs, experience greater failure losses. (2) System resilience to failures can be significantly improved while maintaining other objectives when compared with the traditional design scheme. The proposed method allows for a new perspective in addition to the cost-and-resilience two-objectives design of UDS renovations, especially for systems threatened by various failures.

The model of choosing a microcontroller for the environmental monitoring system module

Problem. The development and application of modern digital technologies for environmental monitoring is an extremely relevant issue. Such environmental monitoring systems allow for dynamic monitoring of the current state of the studied territories in order to further analyze changes and make decisions on their conservation and development. To improve the environmental situation, it is necessary to constantly improve environmental monitoring systems by creating local environmental monitoring systems operating in real time. Goal. The aim of the study is to develop a model for selecting a microcontroller for an environmental monitoring module based on many functional and cost criteria, which will reduce the time of information collection for a regional environmental monitoring system. Methodology. To achieve this goal, we analyzed the characteristics of microcontrollers. A model for selecting a microcontroller for an environmental monitoring module has been developed based on many functional and cost criteria. An example of using the microcontroller selection model for the environmental monitoring module is given. The method of multicriteria optimization allows the selection of a microcontroller for the module of the environmental monitoring system by calculating the utility function. Results. The paper considers the main tasks of the environmental monitoring system. A mathematical model for selecting a microcontroller for the module of an environmental monitoring system has been developed. It belongs to the class of multicriteria discrete programming models and, unlike the known ones, takes into account the system requirements for the module of the environmental monitoring system as a whole. Originality. The developed model allows us to make a microcontroller according to many functional and cost criteria under conditions of fuzzy input information. Practical value. The use of the proposed model for selecting a microcontroller for the module of the environmental monitoring system will reduce the time of collecting information for the regional environmental monitoring system.

Are the Nutritional Properties of Organic Tomatoes Altered by Single and Combined Microbial Soil Inoculants?: A Multiperspective Approach

Biologically active compounds are key-important ingredients of tomato fruits, especially those produced by organic agricultural practices. Being biologically effective soil treatments, microbial inoculants can improve soil quality through a variety of mechanisms. Their activity can influence soil properties and plant development, thereby determining the quantity and quality of the crop. However, little research was done on how these inoculants affect the nutritional quality of the tomato fruit and on the antioxidant status of the fruits. This study investigated lycopene content and total antioxidant capacity of organically grown tomato fruits (Solanum lycopersicum L. var. ‘Mobil’) using various types of single and combined bioeffector products in two growing seasons. Single inoculation contained Trichoderma harzianum, plant growth promoting Pseudomonas sp., and phosphorus-mobilizing Bacillus amyloliquefaciens strains. The combined treatment consisted of biotic Trichoderma harzianum, Pseudomonas fluorescens, and Bacillus subtilis strains with abiotic micronutrients of zinc and manganese. Sum of ranking differences method, as a multicriteria optimization method, was used to rank the treatments and identify the ones deviating the least from the reference treatment. The results showed that all microbial soil inoculants positively affected tomato lycopene content. The combined treatment showed significantly higher lycopene content than the Control in both years. We found that weather and climate conditions also greatly influence the total antioxidant capacity. Based on our results, we recommend the use of combined bioeffective treatments to improve the food quality value of tomato fruits.

Application of The Aggregation and Multicriteria Optimization Method in Assessing the Level of the Knowledge Economy of World Regions in Industry 4.0

The article proposes a new methodology for determining the level of the knowledge economy of countries in terms of the possibilities of using Industry 4.0 technologies. The relevance of the study is due to the transition to a new technological structure – “Industry 4.0” in the world. The aim of the study is to analyze data on the main sub-indices of the knowledge economy associated with Industry 4.0 for countries around the world based on the author’s methodology. As a tool for this analysis, the k-means++ clustering method was used to classify countries according to their characteristics. The assessment of the potential of Industry 4.0 is determined on the basis of 5 criteria characterizing various aspects of the development of countries at the level of economic knowledge. In the calculation process, determining the extent to which the indicators used describe the level of the knowledge economy, and the use of the aggregation formula and multi-criteria optimization, constitutes the scientific novelty of the study. It was concluded that as a result of clustering the countries of the world using the formula Aggregation and Multicriteria Optimization, the number of clusters decreased and the distribution of countries between clusters began to more adequately reflect reality. The results of the study can be used in the process of assessing the competitiveness of countries during the transition to the Industry 4.0 economy, as well as in developing strategies and concepts for countries.

Dry milling of stir-cast and heat-treated EV31A magnesium alloy: An experimental investigation based on the multi-criteria optimization method

The purpose of this study is to examine the impact of various milling parameters and sample preparation methods on the end-milling of EV31A Mg alloy under as-cast, T4, and T6 heat-treated conditions. The test specimens were prepared through stir-casting and heat-treated according to T4 and T6 conditions. The CNC vertical milling machine with the HSS tool was used for the end-milling process based on Taguchi's L9 orthogonal array. Three levels of variation are applied to the process parameters, including spindle speed (S), feed rate (f), depth of cut (d), and test specimen (as-cast, T4, and T6 EV31A). The parameters of surface roughness (Ra, Rz, Sa, Sz), the rate of material removal (MRR), and the cutting force (Fr) were similarly measured. For surface roughness, optical profilometry was used, while the weight loss method and dynamometer were employed, respectively, to assess MRR and Fr. In order to improve the process parameters, TOPSIS (techniques order preferences by similarity to ideal solution) is employed. This method reduces several responses to a single measurable response (the closeness coefficient). S = 1500 rpm, f = 150 mm/min, and aP = 1.5 mm are the ideal process parameters to achieve the maximum closeness coefficient (Ci) of 0. 917129 under as-cast circumstances. Furthermore, analysis of variance (ANOVA) verifies that sample preparation methods of 24.59 % and depth of cut of 38.19 % significantly impact response characteristics.

Analysis of scenarios for transforming the object "Ukryttya" into an environmentally safe system by the method of multicriteria optimization

Based on the criteria for comparative analysis of scenarios grouped into factors, the value of scenarios was determined using the multicriteria optimization methodology. The evaluation methodology includes indicators of weights of factor groups and weights of criteria for the relevant factors. Scenario value assessment is determined by calculating a generalized weighted additive function. It is used to rank the scenarios with the established parametric characteristics of the criteria. The results of the scenario assessment and their ranking are recommendations for making decisions on the sequence of scenario implementation.

A novel cost-palatability bi-objective approach to the menu planning problem with an innovative similarity metric using a path relinking algorithm

Bad eating habits are considered with low exercise, tobacco, and alcohol use, among the greatest health risk factors in high-income countries. Here, the spread of non-communicable diseases related to diet contrasts with the increasing availability of diet guidelines and health information. We are all left wondering, why are we not eating healthier? Palatability and cost appear as the two most important barriers to adherence to any prescribed diet. This work aims to generate high-adherence healthy menus attending to Mediterranean standards, modelling and solving a cost palatability bi-objective optimisation problem. Although the latter is implicitly considered in most current models, its use as a quantifiable objective is novel. For this, a novel Similarity Function is introduced, which evaluates the proximity of two different menus and returns a similarity metric between 0 and 1. A multi-criteria optimisation method is used to design nutritious menu plans and analyse the trade-off between the cost and palatability of menus. A Path Relinking algorithm is later applied to improve the objective values, with specific considerations to palatability, designing healthy menus that can beat those adherence barriers.

Multi-attribute decision making based on VIKOR with probabilistic linguistic term sets: An application to the risk evaluation of foreign direct investment.

The multiple global environments have triggered changes in the international environment, leading to a sharp decline of foreign direct investment (FDI) compared to pre-pandemic level. To evaluate the investment risk of FDI and make optimal investment decision becomes the most important issue for investors. This paper focuses on the evaluation of investment risk for FDI. First, an index system for risk evaluation of FDI is constructed. Then, we introduce the probabilistic linguistic entropy and cross entropy measures, based on which, a programming model is developed to identify the objective attribute weights. A composite weight derivation method, which takes both the objective attribute weights and the subjective attribute weights into account, is further introduced. In view of attributes' uncertainty and fuzziness and the conflicting characteristics of some attributes, the VIKOR (the Serbian name: VlseKriterijumska Optimizacija I Kompromisno Resenje, means multi-criteria optimization and compromise solution) method is used to evaluate the risk of FDI under the probabilistic linguistic environment. Furthermore, a case study is presented to illustrate the proposed method. The comparative analysis and some further discussions verify the validity of the proposed method for the FDI risk evaluation.

Information technology of synthesis of liquid dosing process control

Problem. Currently, different solutions are available on the global market for liquid dosing. There is no universal technology, as the same substances can be dosed using different types of equipment. Therefore, manufacturers face the complex task of determining the most optimal kind of equipment to achieve their goals. These issues are a complex multi-criteria scientific problem, and to effectively address them, it is necessary to develop a technology for synthesizing a liquid dosing control system using multi-criteria optimization methods in different conditions of information determinacy. Goal. The paper aims to increase the efficiency of liquid dosing control by developing information technology for the control system synthesizing. The object of the paper is the process of information technology development for synthesizing the liquid dosing control system. The subject of the paper is the models for the selection of hardware and software for the liquid dosing control system. Methodology. The study analyses and provides a classification of liquid dosing technology and analyses existing liquid dosing control systems. A structural model of information technology for synthesising a liquid dosing control system is developed, and criteria for selecting the elements of the liquid dosing control system are justified. A model for selecting PLC and SCADA systems for synthesising the liquid dosing control system is also developed using hierarchical analysis methods and multi-criteria evaluation and optimisation. Results. The paper resulted in the following: analysis and classification of liquid dosing technology; analysis of existing liquid dosing control systems; development of a structural model of the information technology of synthesising a liquid dosing control system; justification of criteria for selecting the elements of the liquid dosing control system, and the development of a model for selecting PLC and SCADA systems for the synthesis of the liquid dosing control system using hierarchical analysis methods and multi-criteria evaluation and optimisation. Originality. Further development of the methods of hierarchy analysis and multi-criteria assessment and optimization has been achieved by applying them to a specific field – the development of models for selecting hardware and software for the liquid dosing process control system. Practical value. The proposed information technology of synthesising a liquid dosing control system, as well as the mathematical models for selecting hardware and software for the liquid dosing process control system, will reduce the time and cost required to develop such a system.

Energy-efficient torque distribution strategy for four wheel drive electric vehicles based on Traffic zone

This paper presents a four-wheel electric vehicle control system. It incorporates a two-level control strategy for stability and optimal torque distribution to improve fuel efficiency and extend the vehicle’s operational range. The control architecture is structured hierarchically, with a higher level responsible for determining yaw moment and traction forces based on the desired vehicle dynamics. At the lower level, a multi-criteria constrained optimization method is employed, considering both vehicle stability and energy consumption. Additionally, this study takes into consideration the vehicle’s operational context, such as the specific Traffic zone, and the adhesion properties of the tires. This ensures a delicate balance between instantaneous power consumption and overall vehicle stability. The control system’s performance is tested and assessed through three distinct scenarios within the Matlab/Simulink environment. The co-simulation involves the nonlinear vehicle model simulation software, Carsim, and the results are comprehensively compared to the literature.