Minimum Cost Criterion Research Articles

Optimal life-testing plans for joint progressively Type-II censored Birnbaum-Saunders distributions with compound optimal criteria

ABSTRACT In this paper, we first derive the maximum likelihood estimates (MLEs) of the parameters of Birnbaum-Saunders (BISA) distributions based on the joint progressive Type-II censored (JPC) samples. We also discuss using the EM algorithm to obtain the MLEs of the model parameters. Then, we determine the single-objective-criterion optimal JPC schemes for BISA distributions based on the cost minimization criterion, A -optimality criterion, and D -optimality criterion by the complete search method, variable neighborhood search (VNS) algorithm and modified VNS (MVNS) algorithm. These algorithms are compared in terms of accuracy and computation time. In addition, we determine the compound-criterion optimal JPC schemes based on different optimal criteria and the reasonably efficient compound optimal JPC schemes for two competing statistical models, such as the inverse Gaussian and BISA models. The advantages of using the compound optimal scheme over the single-objective-criterion optimal scheme are demonstrated through a real-life data set on the micro-indentation test about the hardness of polymeric bone cement.

Mathematical Modeling for the Optimal Cost Design of Circular Isolated Footings with Eccentric Column

This article shows a model for the design of circular isolated footings and the column placed anywhere in the footing under minimum cost criteria. Some designs for obtaining the diameter, effective depth, and steel areas of the footing under biaxial bending assume the maximum and uniform pressure at the bottom of the footing supported on elastic soils. All these works consider the column placed at the center of the footing. Three numerical problems are given (each problem presents four variants) to determine the lowest cost to design the circular footings under biaxial bending. Problem 1: Column without eccentricity. Problem 2: Column with eccentricity in the direction of the X axis of one quarter of the diameter of the footing. Problem 3: Column placed at the end furthest from the center of the footing on the X axis. The results are verified by the balance of moments, one-way shear or shear and two-way shear or punching. The new model shows a saving of 17.92% in the contact area with soil and of 31.15% in cost compared to the model proposed by other authors. In this way, the proposed minimum cost design model for circular footings will be of great help for the design when the column is placed on the center or edge of the footing.

Optimization of normal operation mode of an electric system with renewable energy sources in Mongolia

This article is aimed at developing an algorithm for optimizing the operation modes of the electric power system of Mongolia, particularly the central power system that include not only conventional thermal power plants, but also renewable sources (wind and solar power plants). This power system accounts for a large share of electricity consumption and generation in Mongolia. The method of linear programming was chosen to minimize financial costs and active power losses during power generation at thermal power plants, while Newton’s method was used to minimize power losses. In addition, the article uses load schedules of each node of the studied power system for its modeling based on the ranking model. Load graphs are predicted using ensemble machine learning algorithms. After the optimization by the criterion of power loss minimization in the grid, power losses were found to be 3.05% of the total power consumption (with power losses in the basic variant of 3.12% and the average selling price of thermal power plants of 0.51 units). Thus, the reduction in losses amounted to 0.07 percentage points, or 2.24%. In terms of the cost minimization criterion, the average selling price of electricity was 0.49 units, i.e., decreased by 3.92%. Average losses of electric power in the grid decreased by 0.6%. According to empirical data, the suggested algorithms can be applied to the optimization of power distribution between thermal power plants by given criteria. The suggested algorithms are implemented using pandapower, a Python-based tool for power system analysis, thus creating a unified system of predictive analytics of power system operation modes

Formation of alternative routes for passenger trains in the event of non-standard situations

Railway passenger transportation has always had a significant place in the economic, material and technical development of Ukraine. The current conditions are no exception, when in connection with the beginning of a full-scale military invasion of our country, passenger transport assumed responsibility for the timely evacuation of people and their safe relocation to other regions of the country or abroad. Due to the fact that railway transport is of strategic importance for Ukraine, its infrastructure has increased risks of destruction. Each destruction of the railway infrastructure has serious consequences for the organization of the movement of passenger trains, in particular high-speed trains. Therefore, with the aim of reducing the possible costs of organizing the movement of high-speed passenger trains in the event of the destruction of the railway infrastructure and increasing the reliability of the functioning of the high-speed railway passenger transport system in Ukraine, an automated technology for providing an alternative route for the trains of the branch “Ukrainian Railway High-Speed Company” (UZShK) is proposed. The formation of this technology is considered on the example of the most popular passenger direction, namely - Kyiv-Lviv, the topology of which is represented by a weighted graph, where the vertices are railway stations, and the edges are railway sections with a weight in the form of a tuple (time to overcome each section, presence of electrification, bandwidth). The proposed technology also provides for the possibility of attracting additional “shuttle” trains or road transport, in cases where it is necessary to significantly reduce the travel time by an alternative route or the possibility of the arrival of railway transport to the station where it is necessary to board/disembark passengers is excluded. The formalization of this process was carried out by forming an optimization mathematical model according to the criterion of minimum operating costs. The formation of a set of alternative routes was carried out using the adjacency matrix of the graph representing the Kyiv-Lviv transportation direction. The developed technology is proposed to be integrated in the form of a software product for automated workplaces (AWP) of operative personnel in the form of a decision support system (DSP), the algorithm of which is also given in this publication.

Guidelines for minimum cost transition planning to a 100% renewable multi-regional energy system

The paper deals with the energy transition, focusing on the decisions to be taken about the change in the energy conversion capacity of specified portion of the universe, such as industrial or domestic districts, regions, countries, etc. Conversion capacity is intended here as the set of all energy conversion and storage units characterized by type, size and number, and interacting with the natural gas and electricity grids. The goal is to find guidelines for new installations, obtained by simulations of a model able to describe properly the behavior of each energy conversion technology and the interaction with grids. The model is based on a traditional MILNP approach, but contains unique features in the literature, which allow to obtain results of general validity for applications to very different geographical areas, or to countries including very different regions that transmit energy with each other or export/import it from abroad. The main novelty of this work is to identify the best planning for the decarbonisation of energy demand sectors, according to the criterion of minimum cost, both at global and at regional level. The results applied to the case of Italy allow identifying clearly the energy demand sectors to which new installations should be applied first to minimize the cost for the total energy system, and the units that must be foreseen to satisfy these energy demands, i.e. a precise strategy for the energy transition towards a 100% renewable system.

METHODICAL APPROACHES TO ENHANCING BUSINESS PROCESSES THROUGH INNOVATION IMPLEMENTATION AT THE ENTERPRISE

Abstract. This article describes the importance of developing high technology and a competitive economy in Kazakhstan, as well as the significance of improving business processes and mechanisms to achieve this goal. The success of enterprises depends on the right strategy, competent leadership, the availability of resources and markets, and efficient business processes.
 The authors discuss the role of innovation in increasing turnover and production growth of enterprises in the modern world. They emphasize the need to quickly adapt production programs to changing customer demands and short product life cycles.
 Special attention is given to the complexity of assessing the beneficial effect of innovations, and two evaluation criteria are presented: the minimum cost criterion and the integrated quality indicator of innovations. It also mentions the use of expert or statistical methods when it is impossible to establish a quantitative relationship between quality indicators and costs.
 In addition, the article describes the establishment of a relationship between costs and comprehensive indicators of technical level and economic efficiency using correlation and regression modeling. A methodology is proposed, including traditional normative approaches and the "cost-effectiveness" method.
 Keywords: foreign economic relations, competitiveness, national economy, innovations, efficiency, quality, technology.

MANAGEMENT OF FINANCIAL RISKS OF ENTERPRISES AS A PREVENTION COMPONENT OF THEIR FINANCIAL INSTABILITY AND BANKRUPTCY FOR THE SUSTAINABLE DEVELOPMENT ACHIEVING

The development is impossible without ups and downs, as a result the stability is disrupted. It is hypothesized that development cannot occur continuously, and therefore it does not exclude the possibility of unstable states. The enterprise unsustainable development is characterized by its financial failure, which is identified with its bankruptcy. At the same time, bankruptcy and liquidation of enterprises in Ukraine is currently a fairly common phenomenon. The purpose of the article is to systematize the methods of financial risk management of enterprises as an ingredient prevention of their financial instability and bankruptcy for achieving sustainable development. A set of general scientific and special research methods were used to solve the set tasks, in particular: generalization and comparison - to establish similarities and differences between the results of research by other authors regarding their understanding of the essence of the categories "development", "sustainable development" and "risk"; grouping of indicators - to operate with information of the kinds and types of risks existing in the scientific literature and to operate with statistical data of the initiated bankruptcy procedures number of legal entities in Ukraine; mathematical - to develop a model for determining the maximum allowable value of lost cash flow of the enterprise, graphic - to visualize the presentation of information, etc. It is substantiated that the prevention of bankruptcy of enterprises is a tool for the sustainable development ensuring. An economic and legal tool is the plan of sustainable development of the enterprise that helps to solve the problem. Its component should be an economic analysis of the company's financial condition. At the same time, any enterprise carries risks related with its business activities. Scientists mostly recommend to use the minimum cost criterion for measures to reduce risk to its acceptable level as the main criterion for risk management. However, the question arises: what risk is considered to be acceptable? For the determination it is advisable to model the movement of the company's cash flows and to identify the limits that lead to unacceptable results for the company, For example, that can lead to the deterioration of the company's financial condition as well as to its bankruptcy and even liquidation. It is taken into account that the economic activity of the enterprise can take place both under normal operating conditions and burdened by certain extraordinary events. The method of determining the maximum permissible risks for enterprises of two groups is substantiated: for the ones, which violation of the bankruptcy procedure in general is possible; for the ones, which violation of the bankruptcy procedure is unlikely. The events that determine the risks during the export of products are considered.

Supply option purchasing decisions via mismatch cost minimization

In this paper, the optimal purchasing decisions of the option procurement of newsvendor-type commodities are studied. Based on the mismatch cost minimization criterion, the present study analyzes the option purchasing decisions of a risk-averse newsvendor under the measure of Conditional Value-at-Risk (CVaR). For the purpose of controlling the procurement risk, it is found that a newsvendor’s optimal option purchasing decision under the CVaR measure increases at the quantile level under certain conditions. The result provides alternative explanations for a newsvendor’s over-purchasing behaviors in reality. To mitigate the conservativeness of the CVaR measure, a combined objective defined as the mean-CVaR on mismatch cost is introduced, and the optimal option purchasing decision of a newsvendor minimizing the combined objective is derived. The combined objective can strike a balance between the minimization of CVaR of mismatch cost as well as the minimization of expected mismatch cost. In addition, a sensitivity analysis is performed to exhibit the results and managerial insights are presented to hedge against the potential risks for newsvendors in the option purchasing decision-making.

Optimal scale selection based on multi-scale single-valued neutrosophic decision-theoretic rough set with cost-sensitivity

The selection of optimal scale has always been the essential problem of multi-scale system. However, most of the current studies only consider the consistency of the system, and ignore the cost information. Therefore, based on the ranking methods of single-valued neutrosophic number, this paper constructs a multi-scale dominant single-valued neutrosophic system. Furthermore, the test cost is defined according to the relative distance preference degree, and the risk cost of Bayesian theory introduced by decision-theoretic rough set is used as the decision cost of accepting, delaying and rejecting decisions. Therefore, we establish a multi-scale dominant single-valued neutrosophic decision-theoretic rough set based on test and decision cost. In addition, we also propose a scale updating algorithm to find out all consistent scales. Afterwards, we further raise an optimal scale selection algorithm based on the minimum total cost criterion. Finally, the algorithm is verified and analyzed by UCI data sets. The algorithm and model proposed in this paper further expand the application of single-valued neutrosophic rough set in multi-scale system, and provide a reference for subsequent research in this field.

Methodology for determining technical, economic and environmental performance of combined power plants

Consideration of the feasibility of building combined power plants (CPP) based on renewable energy sources (RES) and the choice of parameters, type of equipment, layout, and design solutions is based on an assessment of economic efficiency, the indicator of which is the ratio between the required investments and the achieved technical and economic effect. An accurate assessment of economic efficiency is a rather difficult task since it is necessary to take into account a large number of factors, for example, specific features of design solutions, operating conditions of the CPP depending on the requirements of the consumer, the stochastic nature of the manifestation of energy resources, the possible mode of operation of the CPP for the needs of individual consumers and others. An approach based on the minimum cost criteria has been widely used for the economic justification of the objects under construction for a long time. In rigidly centralized economic management, such an approach based on ensuring optimal construction planning played an important role in increasing the scientific validity of economic decisions. It proceeded from the global and national economic goals of economic development. In the conditions of a free market economy, a method of evaluating the effectiveness of taking into account all the main features of it is necessary.

ОПТИМИЗАЦИЯ СИСТЕМЫ ОБЕСПЕЧЕНИЯ ЗАПАСНЫМИ ЧАСТЯМИ ПРОИЗВОДСТВЕННЫХ ПОДРАЗДЕЛЕНИЙ АЭРОПОРТОВОЙ СЕТИ

The problem of optimal design of the spare parts supply system for the baggage handling systems of a group of airports is solved. It is assumed that the airports belonging to the group will be equipped with baggage systems of one manufacturer, which will supply them with spare parts during the operational phase. One of the airports will function as a passenger transfer center (hub) for a hub-forming airline, which will organize mass transfer flights between the airports of the group. The proposed system will consist of a tiered system for spare parts supply, including warehouses at the manufacturer's, hub airport and other (peripheral) airports, and a combined strategy of spare parts supplies, including periodic supplies from the manufacturer's warehouse to the warehouses of airports, on-line supplies from the hub warehouse to the warehouses of peripheral airports, and, in case of deficit, on-line supplies to the hub airport's warehouse. The aim of the solution of the problem is to determine the volume of spare parts production which is optimal by the criterion of minimum costs of production, storage and stock replenishment. The results of model examples, testifying to the validity of the considered statement of the problem and efficiency of the proposed system of spare parts supply, are presented.

Active learning for ordinal classification based on expected cost minimization

To date, a large number of active learning algorithms have been proposed, but active learning methods for ordinal classification are under-researched. For ordinal classification, there is a total ordering among the data classes, and it is natural that the cost of misclassifying an instance as an adjacent class should be lower than that of misclassifying it as a more disparate class. However, existing active learning algorithms typically do not consider the above ordering information in query selection. Thus, most of them do not perform satisfactorily in ordinal classification. This study proposes an active learning method for ordinal classification by considering the ordering information among classes. We design an expected cost minimization criterion that imbues the ordering information. Meanwhile, we incorporate it with an uncertainty sampling criterion to impose the query instance more informative. Furthermore, we introduce a candidate subset selection method based on the k-means algorithm to reduce the computational overhead led by the calculation of expected cost. Extensive experiments on nine public ordinal classification datasets demonstrate that the proposed method outperforms several baseline methods.

Mathematical model of the passage of audio signals in network-based audio analytics systems

Relevance. Nowadays, more and more audio and video analytics systems work together. But in many cases, it is necessary to quickly transfer the audio stream. Therefore, the task of reducing delays in transmission of audio streams in network-based audio analytics systems becomes relevant. The object of research is the process of audio signal transmission. The subject of research is mathematical models of audio and video streams in network systems. The purpose of this paper is to develop a mathematical model for the passage of audio signals in network-based audio analytics systems. Research results. The statement of the problem of optimizing the network of connecting lines according to the criterion of minimum capital costs is proposed. Optimization equations for a unidirectional three-node basic structure are compiled based on the problem of minimizing capital costs. Optimization equations are obtained for a bidirectional three-node basic structure. Obtained optimization equations are generalized to any structure of a network of connecting lines. The direction of further research is the development of an approximate method for quickly solving optimization equations for a network of connecting lines and assessing the adequacy of the developed model.

Simultaneous optimization of inventory, maintenance, and quality for production systems subject to multiple mean and variance shifts

This article presents a general, integrated production, quality, and condition-based maintenance model for imperfect processes with multiple out-of-control operating states. The production system is subject to multiple quality disruptions, which affect both the process mean and variance, and failures. The quality of the production process output is monitored by a fully adaptive control scheme, and the state of deterioration is estimated through periodic sampling inspection. The proposed control scheme’s operation is modeled through a Markov chain, and the optimal quality control, maintenance, and inventory policy are defined based on an expected total cost minimization criterion. Finally, an illustrative example is employed to demonstrate the operation of the proposed model, sensitivity analysis is conducted to generate insights into how the process parameters misspecification affects the economic performance, and a comparative study is performed to evaluate the model’s superiority against the respective single quality shift model.

Statistical inference and optimum life-testing plans with joint progressively type-II censoring scheme

ABSTRACT This article discusses the estimation of model parameters and the determination of optimal life-testing plans for Weibull-distributed lifetimes under a joint progressive Type-II censoring scheme. We obtain the maximum likelihood estimates numerically and propose a modified variable-neighborhood-search-based approach for determining the optimum joint progressive Type-II censoring scheme. Different optimal criteria, including a cost minimization criterion, the A-optimality criterion, and the D-optimality criterion, are considered. A sensitivity analysis is used to study the effect of misspecification of parameter values on the optimal schemes.

Пути повышения эффективности логистического обеспечения деятельности международной транспортной системы «Агроэкспресс» на основе инструментария однокритериальной оптимизации

Purpose: To develop technology variants to provide for necessary level of cargo traffic for trains “Agroexpress” and mathematical model proposal for these purposes. Methods: System analysis, operation mathematical optimization and linear programming. Results: Work flows on provision of agricultural cargos of the being considered train are analyzed. Mathematical model of provision of agro-production of “Agroexpress” trains in Uzbekistan is developed. With the help of the model, there is a possibility to improve work technology on provision of cargo traffic of “Agroexpress” in sufficient quantity by minimal expenditure criterion. Practical importance: The proposed model creates favorable conditions for increasing foreign cargo traffic of Russia and Uzbekistan. With the help of the model it is possible to improve the technology of work to ensure the cargo traffic in a sufficient number of “Agroexpress” on the criterion of minimum costs.

Optimization-based analysis of integrated lignocellulosic biorefineries in Spain focusing on building blocks

Spain, in the framework of the European Green Deal, has set ambitious climate and energy goals for 2030. Lignocellulosic biorefineries can make a strong contribution to these goals; however, advanced biofuels generally cannot be produced in a profitable way compared to fossil and first-generation fuels. To address this problem, the efficient production of a wide range of bioproducts, not only biofuels and bioenergy, may be the solution. Therefore, a systematic evaluation of the near-term economic potential bio-building blocks (xylitol, sorbitol, succinic, glutamic, glucaric, levulinic, lactic, and itaconic acids) is presented. Many possible combinations of feedstock and conversion technologies can be considered feasible pathways to manufacture advanced biofuels and bio-based building blocks. To map the optimal groups of technologies in the framework of Spain’s biorefineries, we apply a methodology based on a network optimization approach that combines minimum cost and energy criteria together with feedstock availability and demand constraints. The feedstocks analyzed are pine and eucalyptus residues and olive tree pruning wastes, being three largely available agroforesty residues in Spain. The results show that building blocks show good economic and energy performance compared to advanced transportation biofuels, and although their demand is much lower, they should be considered to improve the profitability of biorefineries. Secondly, advanced gasoline, bioethanol, hydrogen, and building blocks demands can be satisfied with pine, eucalyptus, and olive residues available in Spain. Finally, lactic acid production is profitable, but the remaining routes do not reach the break-even point, suggesting that further research is still needed.

Inventory Control of Vegetable Oil Products Using Continuous Review System (Q) Approach and Periodic Review System (P) Methods in Retail Companies: A Case Study of Indonesia

Retail companies are businesses that have a significant role in providing quality staples to improve public health. Every retail company wants the production inventory control system to run well to meet consumer demand. Suppose the amount of inventory ina retail company is too small. In that case, it will disrupt consumer demand for products that consumers want to buy and lose the opportunity to earn profits if an order is more significant than forecast. Meanwhile, if product inventory exceeds the need for a product, it will cause high costs, and if stock is stored for too long, it will result in damage and expiration. This retail company sells quality products and provides a wide range of excellent and complete products and makes it easier for customers to find their needs as one of the best. A company that needs to have a product control system to maintain sales and sell quality products and finally compete with other national and foreign retail companies. However, the current product inventory processing is not optimal because it is only based on previous inventory data. It can be seen from the varying amount of inventory and the high frequency of ordering. This study aims to obtain the most optimal comparison results by using the minimum total cost criteria and minimizing the cost of purchasing the product. This study compares two methods, namely the Continuous Review System (Q) method and the Periodic Review System (P) method. The most suitable method was the Q method with the total inventory cost of Vegetable Oil Products of Rp in this study. 13,371,600 with an efficiency of 42% of the entire inventory costs incurred by retail companies.

Optimal Energy Management Solutions Using Artificial Intelligence Techniques for Photovoltaic Empowered Water Desalination Plants Under Cost Function Uncertainties

Two modern methods of the energy management system (EMS) based on a modified cost function are addressed in this paper. Fuzzy logic (FL) and Harris Hawks Optimization (HHO) is implemented to achieve the optimal performance of seawater desalination plants (SWDP) within the minimum feed-in tariff (FiT). The technical difficulties involved in the variation of energy price from one time to another and the system parameters uncertainties. For example, the price of energy is higher at the peak time and the price is lower at normal times. Also, the peak time can change from one day to another day. The proposed management system can deal with these variations and uncertainty cases. The suggested EMS is achieved through a bidirectional electrical energy interchange approach (π-EEIA). The main concept behind the proposed π-EEIA is how and when to inject the excess generated energy of renewable energy into the utility grid or charge the battery depending on the minimum dynamic cost criterion and vice versa. To accomplish this study a 700 m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> /day SWDP located in Egypt fed on solar energy and a utility network has been constructed and analyzed. The system includes SWDP fed from a photovoltaic (PV) array as well as the utility grid in addition to a battery energy storage system (BESS). The main objective of this study is the management and coordination between the energy exchange process from the solar energy, the utility network, and BESS to provide sufficient electrical energy for SWDP within the minimum FiT. The system is constructed and validated using the MATLAB/SIMULINK <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">TM</sup> software package. The proposed FL and HHO-based EMSs are investigated in the presence of the system uncertainties such as the change in the energy (excess or shortage) as well as the change in the energy price in the utility network (high or low) with (normal or peak) time. The attained results demonstrate that the proposed FL and HHO-based EMSs provide high dynamic performance and accurate coordination between various energy resources and BESS. The results show that FL-based EMS achieves a profit of 10.28 $ but the HHO-based EMS achieves a profit of 10.11 $ in the same period.

ОПТИМИЗАЦИЯ ФУНКЦИОНИРОВАНИЯ ПОДВИЖНОГО СОСТАВА ДЛЯ ПЛАНИРОВАНИЯ ГРУЗОВЫХ АВТОМОБИЛЬНЫХ ПЕРЕВОЗОК В УСЛОВИЯХ КРАЙНЕГО СЕВЕРА

The article develops a mathematical model for planning road freight transportation, which corresponds to the practice of rolling stock functioning in the conditions of the Far North. The formation of the optimal list of standard sizes of the rolling stock is carried out according to the criterion of minimum costs using an iterative optimization method. The limitations of the mathematical model are formulated taking into account the operating conditions, the conditions of the Customers, ensuring the operability of the rolling stock, the technology for performing transportation, the relationship between the operation of the rolling stock and special equipment.