Wyniki wyszukiwania - BazTech

1

A generalized composition approach in network data envelopment analysis for complex structures : an application of higher education institutions in Poland

Sotiros Dimitrios, Koronakos Gregory, Żołądkiewicz Julia

Operations Research and Decisions

|

2025

|

Vol. 35, No. 1

108--139

EN

We present in this paper the pitfalls of the most established approach in network data envelopment analysis for units with a parallel internal structure. We show that these pitfalls are the cause of deficiencies of prevalent models employed for general series structures. To overcome these issues, we build a general composition approach that can be applied to units with any type of structure. Our approach relies on multi-objective programming and, unlike existing methods in the literature, we identify the divisional efficiency scores in a min-max and max-min sense simultaneously. This allows us to identify unique and unbiased efficiency scores that are not affected by the different magnitude of scores that the divisions can attain. Comparisons with other approaches, under various structures and assumptions, highlight the advantages of the proposed approach. We further employ this new approach to evaluate the teaching and research efficiency of the top 19 public higher education institutions in Poland with data drawn from the period 2020–2021. The proposed assessment framework departs from the employment of standard metrics such as number of publications and journal rankings, commonly used to evaluate the quantity and quality of research outcomes, and relies on other proxies, such as field-weighted citation impact factor and volume of research grants, that may provide more reliable results.

2

Optimal Operator Assignment and Cell Loading in Labor-Intensive Manufacturing Systems with Inter-Cell Operator Sharing

Kuo Yiyo, Chen Shih-Chen

Management and Production Engineering Review

|

2025

|

Vol. 16, No. 4

[nr art. 6], s. 1--12

EN

This research deals with an operator assignment and cell loading problem in multi-cell production systems with inter-cell operator sharing. A two-phase methodology is proposed to minimize the total manpower requirement. In the first phase, manpower configurations for all products with all levels of manpower available will be generated taking inter-cell operator sharing into consideration. The second phase optimizes the cell loading and selects the manpower configuration for all cells when given a product mix. In order to further reduce manpower requirements, lot-splitting is considered. For both phases, the corresponding mathematical models, which can be optimized by commercial software, LINGO 17, are developed. A case study of a jewelry manufacturing company proposed taken from the literature is adopted to test the proposed methodology. The results show the strategy of inter-cell operator sharing can save 11.56% manpower at most. Moreover, if lot-splitting is considered, at most 14.66% of manpower can be saved.

3

Method of truck crew work coordination on international routes

Taran Igor, Zhumatayeva Gaziza, Oliskevych Myroslav, Szarata Mateusz

Transport Problems

|

2024

|

T. 19, z. 2

205--218

EN

The article deals with the problem of increasing the productivity of trucks in the performance of international road freight transportation in Eastern Europe and the European Union. There are restrictions on cabotage transportation (domestic cabotage), as well as time limits for the execution of orders and penalties for the execution of the entire volume of transportation in this case in addition to the restrictions of the European Agreement E/ECE/TRANS/564. The task of optimizing the required number of vehicles, drivers/driving crews, and route configuration was formulated and solved by mathematical programming with time constraints. At the same time, a variable method of organizing the work of drivers on adjacent routes was applied, by which drivers/crews are not assigned to a specific vehicle but are changed after a certain number of work hours. This minimized the non-productive idling of trucks, ensured compliance with the work and rest regulations of drivers, and minimized truck mileage on routes. In contrast to known methods and research results, the problem is solved with a guaranteed achievement of the optimum in an acceptable search time. This result was achieved due to the appropriate formulation of the solution conditions. The results can be applied in the logistic planning of transport processes.

4

Matheuristics for the Order-picking Problem with Sequence-dependant Constraints in a Logistic Center with a One-directional Conveyor Between Buffers

Czerniachowska Kateryna, Wichniarek Radosław, Żywicki Krzysztof

Management and Production Engineering Review

|

2024

|

Vol. 15, No. 1

140--160

EN

In the logistics center (warehouse or distribution center), customer orders need to be picked up by the pickers. In this research, we examine the order-picking problem with sequencedependent constraints with two decision variables (container start time and product quantity) in a distribution center with a one-directional conveyor. The decision-making is based on the developed two variations of two-step matheuristics. At first, the main order-picking problem is divided into two subproblems. Next, each step of each variant of the subproblem is solved using a mathematical programming-based technique. Both matheuristics were better in 85 of 120 test instances compared to the initial model solved by mathematical programming. Pickers matheuristics were better on average at 46.56%, while Buffers matheuristics were better on average at 46.87%. The proposed matheuristics approach allows distributors to schedule orders in the logistics center fast enough and with fewer resources.

5

Optimization programming tools supporting supply chain management

Szkutnik-Rogoż Joanna, Małachowski Jerzy

Bulletin of the Polish Academy of Sciences. Technical Sciences

|

2023

|

Vol. 71, nr 3

art. no. e145570

EN

The issue of transportation is a particular type of mathematical programming that facilitates searching for and determining an optimal distribution network, considering the set of suppliers and recipients. This paper uses a numerical example to present a solution to a transport problem utilizing classical computation methods, i.e., the northwest corner, the least cost in a matrix, and the VAM approximation method. The objective of the paper was to develop tools in the form of algorithms that would then be implemented in three various computing environments (R, GNU Octave, and Matlab) that allow us to optimize transport costs within an assumed supply network. The model involved determining decision variables and indicating limiting conditions. Furthermore, the authors interpreted and visualized the obtained results. The implementation of the proposed solution enables users to determine an optimal transport plan for individually defined criteria.

6

Toward an Optimal Solution to the Network Partitioning Problem

Ferdowsi Arman, Chenary Maryam Dehghan

Annals of Computer Science and Information Systems

|

2023

|

Vol. 35

111--117

EN

This paper delves into the realm of community detection in network science and graph theory‎ ‎with the overarching objective of unraveling the underlying structures between nodes within a network‎. ‎In this pursuit‎, ‎we put forth a novel and comprehensive approach to ascertain the optimal solution to maximizing the renowned community quality metric known as Max-Min Modularity‎. ‎Through a series of experiments encompassing diverse case studies‎, ‎we substantiate the efficacy and validity of our proposed approach‎, ‎further bolstering its credibility‎.

7

Koncepcja modelu matematycznego do optymalnego doboru urządzeń drukujących z uwzględnieniem kosztów zużycia energii elektrycznej

Kaszyński Przemysław, Rój Roman

Rynek Energii

|

2021

|

Nr 2

65--70

PL

Rosnące ceny energii elektrycznej stanowią istotny składnik kosztów przedsiębiorstw funkcjonujących na rynku i konkurujących z innymi podmiotami. W związku z powyższym, poszukiwane są metody umożliwiające redukcję zużycia energii, a w konsekwencji kosztów z tym związanych w poszczególnych obszarach działalności przedsiębiorstw. Do rozwiązania tego rodzaju problemów zastosowanie mogą mieć metody analizy systemowej z zakresu modelowania matematycznego. W artykule przedstawiono koncepcję opracowania modelu matematycznego optymalizującego dobór i rozmieszczenie urządzeń drukujących w przedsiębiorstwie, w celu redukcji kosztów całkowitych związanych z realizacją wydruków w danym okresie. Koszty te obejmują zarówno koszty zakupu i serwisu urządzeń drukujących oraz koszty zakupu materiałów eksploatacyjnych, jak również koszty zużycia energii elektrycznej oraz koszty związane z odległością instalacji wspomnianych urządzeń od stanowisk pracy.

EN

Soaring electricity prices substantially impact the costs of companies operating on the market and competing with other enterprises. Therefore, the development of decision-support tools that enable the reduction of electricity consumption and electricity costs in various areas of their operation is highly desirable. Methods for system analysis in the field of mathematical modeling may be used to solve such problems. The paper presents the concept of a mathematical model that optimizes the selection and allocation of printing devices in a company. The mathematical framework aims to minimize the total costs associated with the use of the printing fleet by considering the costs of purchasing and servicing printing devices, costs of purchasing consumables, costs of electricity consumption, and costs related to the distance between printing devices and workstations.

8

A Method to Improve Planning of Product Placement on a Printing Sheet

Czerniachowska Kateryna, Żywicki Krzysztof, Wichniarek Radosław

Management and Production Engineering Review

|

2021

|

Vol. 12, No. 1

119--128

EN

Major manufactures are moving towards a sustainability goal. This paper introduces the results of collaboration with the leading company in the packaging and advertising industry in Germany and Poland. The problem addresses the manufacturing planning problem in terms of minimizing the total cost of production. The challenge was to bring a new production planning method into cardboard manufacturing and paper processing which minimizes waste, improves the return of expenses, and automates daily processes heavily dependent on the production planners’ experience. The authors developed a module that minimizes the total cost, which reduces the overproduction and is used by the company’s manufacturing planning team. The proposed approach incorporates planning allowances rules to compromise the manufacturing requirements and production cost minimization.

9

An Algorithm for Choosing, Ordering a New Criteria of a Bi-Objective Flow Problem

Belkacem Salima Nait

Foundations of Computing and Decision Sciences

|

2021

|

Vol. 46, No. 1

11--26

EN

In this paper, we propose an algorithm which is based on many things: the notions well-known of the simplex network method, Ford Fulkerson’s algorithm and our new idea, which is << the gain cycles >>, applied on a bi-objective minimum cost flow problem. This algorithm permits us to have a good order of many criteria in a rapid and an efficient way; because this classification permits us to structure the optimal area, in which we can choose the best action among the others which exist in the objective space. From this one, we distinguish, that the resolution of this problem comes to find an under set of good actions, among which the decider can select an action of best compromise, or make a decision, in the case where reference indications of the deciders may change. A didactic example is done to illustrate our algorithm.

10

On the strong metric subregularity in mathematical programming

Osmolovskii Nikolai P., Veliov Vladimir M.

Control and Cybernetics

|

2021

|

Vol. 50, No. 4

457--471

EN

This note presents sufficient conditions for the property of strong metric subregularity (SMSr) of the system of first order optimality conditions for a mathematical programming problem in a Banach space (the Karush-Kuhn-Tucker conditions). The constraints of the problem consist of equations in a Banach space setting and a finite number of inequalities. The conditions, under which SMSr is proven, assume that the data are twice continuously Fréchet differentiable, the strict Mangasarian-Fromovitz constraint qualification is satisfied, and the second-order sufficient optimality condition holds. The obtained result extends the one known for finite-dimensional problems. Although the applicability of the result is limited to the Banach space setting (due to the twice Fréchet differentiability assumptions and the finite number of inequality constraints), the paper can be valuable due to the self-contained exposition, and provides a ground for extensions. One possible extension was recently implemented in Osmolovskii and Veliov (2021).

11

Social Network Optimization for Cluster Ensemble Selection

Zhao Chenyue, Alizadeh Hosein, Minaei Behrouz, Mohamadpoor Majid, Parvin Hamid, Mahmoudi Mohammad Reza

Fundamenta Informaticae

|

2020

|

Vol. 176, nr 1

79--102

EN

This paper studies the cluster ensemble selection problem for unsupervised learning. Given a large ensemble of clustering solutions, our goal is to select a subset of solutions to form a smaller yet better performing cluster ensemble than using all available solutions. The common way of aggregating the chosen solutions is accumulating the information of the selected results to a similarity matrix. This paper suggests transforming the similarity matrix to a modularity matrix and then applying a new consensus function which optimizes modularity measure in it. We represent the modularity maximization problem as a 0-1 quadratic program which can be exactly solved for small datasets. We also established a new greedy algorithm, namely sum linkage, to optimize the objective function specially for large scale datasets in a very short time. We show that the proposed consensus partition gets much closer to the actual cluster structure than the partitions obtained from the direct application of common cluster ensemble methods. The promising results compared with other most cited consensus functions show the excellent efficiency of the proposed method.

12

Exact and approximation algorithms for joint routing and flow rate optimization

Junosza-Szaniawski Konstanty, Nogalski Dariusz

Annals of Computer Science and Information Systems

|

2019

|

Vol. 20

29--36

EN

This paper addresses comparison of algorithms for a version of the NUM problem. The joint formulation of routing and transmission rate control within the multi-user and single-path setting is assumed within the NUM. Since problem is NP-hard, the efficient heuristics are designed, implemented and compared experimentally with other existing heuristics and exact linear programming solver. The linear approximation is applied for nonlinear utility function. The results of experiments demonstrate a trade-off between computing time and precision of goal value.

13

Python programming language as a tool for creating three-dimensional figures of glider aerobatics

Linka A., Wróblewska A.

Journal of KONES

|

2018

|

Vol. 25, No. 4

247--253

EN

The article presents the possibilities and validity of the implementation in the field of developing mathematical models for aerobatics trajectory. Proposing a catalogue of three-dimensional figures and those described mathematically will allow improving judging and scoring level, as well as the art of piloting in aerobatics. In the first chapter, article describes the processes of aerobatic flight, judge evaluation method and the current state of technology supporting the scoring process. The second chapter presents the capabilities of the Python programming language, which will be a tool for the construction of three-dimensional models. The third chapter of this article is a description of the comparative analysis of ideal trajectories and obtained in real flight. This chapter also demonstrates the validity and necessity of introducing new standards for assessing aerobatic flights. Aerobatics flights and judging, intelligent system to control aerobatic flights, three-dimensional models of aerobatic flights are presented in the article. The article concerns on use modern technologies to support the judges during the competition. The introduction of ASSD + PL system and the possibility of implementing designed models of aerobatic figures open new paths for improving the art of pilotage and arbitration.

14

Optimal shakedown of the thin-wall metal structures under strength and stiffness constraints

Alawdin P., Liepa L.

Civil and Environmental Engineering Reports

|

2017

|

No. 25(2)

25--41

EN

Classical optimization problems of metal structures confined mainly with 1st class cross-sections. But in practice it is common to use the cross-sections of higher classes. In this paper, a new mathematical model for described shakedown optimization problem for metal structures, which elements are designed from 1st to 4th class cross-sections, under variable quasi-static loads is presented. The features of limited plastic redistribution of forces in the structure with thin-walled elements there are taken into account. Authors assume the elastic-plastic flexural buckling in one plane without lateral torsional buckling behavior of members. Design formulae for Methods 1 and 2 for members are analyzed. Structures stiffness constrains are also incorporated in order to satisfy the limit serviceability state requirements. With the help of mathematical programming theory and extreme principles the structure optimization algorithm is developed and justified with the numerical experiment for the metal plane frames.

PL

Klasyczne problemy optymalizacji konstrukcji metalowych dotyczą głównie klasy 1 przekrojów. Jednak w rzeczywistych konstrukcjach cienkościennych często stosują się przekroje wyższych klas. W niniejszej pracy zaproponowano nowy model matematyczny dla optymalizacji przystosowania konstrukcji metalowych, w których przekroje elementów odnoszą się zarówno do klasy 1 jak i do 4 łącznie, przy obciążeniach zmiennych quasi-statycznych. Uwzględniono możliwości ograniczonej redystrybucji sił resztkowych w konstrukcji z elementów cienkościennych. Autorzy zakładają sprężysto-plastyczne wyboczenie na skutek zginania w jednej płaszczyźnie, bez wyboczenia bocznego na skutek skręcania. Wzory obliczeniowe według Metody 1 i 2 dla elementów są analizowane. Ograniczenia sztywności są również zastosowane w celu spełnienia wymogów stanu granicznego użytkowalności. Za pomocą teorii programowania matematycznego i ekstremalnych zasad stworzono algorytm optymalizacji konstrukcji i uzasadniono w eksperymencie numerycznym dla płaskich ram metalowych.

15

Management decisions in logistic systems

Kuhan S.

Studia i Materiały / Europejska Uczelnia Informatyczno-Ekonomiczna w Warszawie

|

2016

|

Nr 2(12)

27--36

EN

Adoption of administrative decisions in logistic systems is rather important problem of management. Being the difficult cybernetic system having feedback, the logistic system consists, as a rule, of several subsystems and has the developed communications with the external environment. Analyzing and choosing versions of administrative decisions it is necessary to use mathematical methods that will allow to assess correctly a real situation and to receive optimum values of the set parameters of economic objects.

PL

Podejmowanie decyzji dotyczących zarządzania w systemach logistycznych jest bardzo ważnym zagadnieniem. Będąc złożonym systemem cybernetycznym, posiadającym sprzężenie zwrotne, system logistyczny składa się z reguły z kilku podsystemów i posiada rozbudowane powiązania z zewnętrznym otoczeniem. W trakcie analizy mającej na celu podjęcie najlepszej decyzji konieczne jest zastosowanie metod matematycznych, które pozwolą właściwie ocenić sytuację i uzyskać optymalne wartości parametrów ekonomicznych.

16

Scheduling preemptable jobs on identical processors under varying availability of an additional continuous resource

Różycki R., Waligóra G., Węglarz J.

International Journal of Applied Mathematics and Computer Science

|

2016

|

Vol. 26, no. 3

693--706

EN

In this work we consider a problem of scheduling preemptable, independent jobs, characterized by the fact that their processing speeds depend on the amounts of a continuous, renewable resource allocated to jobs at a time. Jobs are scheduled on parallel, identical machines, with the criterion of minimization of the schedule length. Since two categories of resources occur in the problem: discrete (set of machines) and continuous, it is generally called a discrete-continuous scheduling problem. The model studied in this paper allows the total available amount of the continuous resource to vary over time, which is a practically important generalization that has not been considered yet for discrete-continuous scheduling problems. For this model we give some properties of optimal schedules on a basis of which we propose a general methodology for solving the considered class of problems. The methodology uses a two-phase approach in which, firstly, an assignment of machines to jobs is defined and, secondly, for this assignment an optimal continuous resource allocation is found by solving an appropriate mathematical programming problem. In the approach various cases are considered, following from assumptions made on the form of the processing speed functions of jobs. For each case an iterative algorithm is designed, leading to an optimal solution in a finite number of steps.

17

Application of the mathematical programming in solving the managerial problems encountered in the production, trade of construction materials and purchases organization

Boroń J., Bartyla P.

Czasopismo Techniczne. Budownictwo

|

2016

|

Y. 113, iss. 2-B

17--36

EN

The article presents, in a manager friendly way, three practical applications of methods of mathematical programming as tools for computer-aided purchase organisation and sawmill order realisation. The problems are illustrated by examples of optimising: the head saw use in planning the timber production realisation, the purchases for small warehouse and the supply of cement to the network of concrete plants or precast plants.

PL

W niniejszej pracy zaprezentowano w sposób przyjazny dla menedżerów budownictwa trzy skrajnie różne przykłady praktycznego zastosowania programowania matematycznego w planowaniu produkcji tartacznej, zaopatrzenia małej hurtowni materiałów budowlanych i organizacji dostaw do sieci zakładów produkujących prefabrykaty betonowe.

18

Optimization of the structures at shakedon and Rosen's optimality criterion

Alawdin P., Atkociunas J., Liepa L.

Civil and Environmental Engineering Reports

|

2016

|

No. 22(3)

5--23

EN

Paper focuses on the problems of application of extreme energy principles and nonlinear mathematical programing in the theory of structural shakedown. By means of energy principles, which describe the true stress-strain state conditions of the structure, the dual mathematical models of analysis problems are formed (static and kinematic formulations). It is shown how common mathematical model of the structures optimization at shakedown with safety serviceability constraints (according to the ultimate limit state (ULS) and serviceability limit state (SLS) requirements) on the basis of previously mentioned mathematical models is formed. The possibilities of optimization problem solution in the context of physical interpretation of optimality criterion of Rosen‘s algorithm are analyzed.

PL

W pracy przedstawiono problemy zastosowania ekstremalnych zasad energetycznych i nieliniowego programowania matematycznego w teorii przystosowania konstrukcji. Za pomocą zasad energetycznych, które opisują rzeczywiste stany naprężenia-odkształcenia konstrukcji, tworzone są dualne modele matematyczne analizowanych problemów (sformułowania statyczne i kinematyczne). Pokazano jak na podstawie wyżej wymienionych modeli matematycznych formułowany jest ogólny model matematyczny optymalizacji konstrukcji przy uwzględnieniu ograniczeń w postaci stanów granicznych nośności/bezpieczeństwa i użytkowalności. Analizowane są możliwości rozwiązania problemu optymalizacji w kontekście fizycznej interpretacji kryterium optymalności algorytmu Rosena.

19

Reprezentacja zapotrzebowania na moc w długoterminowych modelach systemów paliwowo-energetycznych

Kamiński J., Kaszyński P., Malec M.

Rynek Energii

|

2015

|

Nr 3

3--9

PL

Artykuł prezentuje problem implementacji zapotrzebowania na moc w długoterminowych modelach systemów paliwowo-energetycznych. Przedstawiono dwa najczęściej stosowane podejścia, a mianowicie: (i) wykorzystanie reprezentatywnych krzywych obciążeń oraz (ii) zastosowanie krzywych trwania obciążeń. Następnie przedstawiono przykład implementacji zapotrzebowania na moc w długoterminowym modelu krajowego sektora wytwórczego PolPower_LR. Na podstawie przyjętych scenariuszy badawczych, różniących się stopniem szczegółowości odwzorowania zapotrzebowania na moc, przeanalizowano wpływ założeń scenariuszowych na liczbę zmiennych i równań modelu, czas obliczeń oraz jakość uzyskanych wyników. W podsumowaniu zestawiono najważniejsze konkluzje wynikające z przeprowadzonej analizy.

EN

The paper presents the problem of representation of power demand in the long-run computable models of energy systems Two general approaches are analysed, namely: (i) application of the representative load curve and (ii) application of the load duration curve. A case study of the implementation of power demand in long-run mathematical model of the Polish power generation sector (PolPower_LR) is presented. Five scenarios assuming different resolutions of demand curve (each scenario with different level of detail of representative levels of power demand) are analysed. The impact of scenario assumptions on the number of variables and equations of the model, as well as the computation time and the quality of results is discussed. In conclusions the most important findings are summarised.

20

Milk runs model with overtime: application to cluster supply chain

Tomczak M., Bucoń R.

Budownictwo i Architektura

|

2015

|

Vol. 14, nr 4

139--147

EN

Paper identifies obstacles limiting functioning and development of small and medium construction enterprises. It also includes a description of cluster supply chain (CSC) idea as a suggested solution to some of the problems resulting from the small scale of company activities. One of more important issues of every distribution centre, i.e. portions of deliveries smaller than truck capacity for particular consumers, is also discussed. This problem was formulated for the first time in dairy industry, therefore, it was called milk runs. Moreover, the authors of this paper presented the outcome analysis of survey carried out among construction engineers and managers. This study aimed at determining organizational principles for logistic centre working with CSC framework. The mathematical model depicting milk runs deliveries with overtime consideration, done for many construction sites within a distribution centre is presented hereunder. This model may be potentially used to optimize distribution centres working within cluster supply chain framework.