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1

The need for simulation in complex industrial systems

100%
Aboura K., Kljajić M., Eskandarian A.
Organizacija
|
2012
|
vol. 45
|
issue 5
219-227
EN
We discuss the concept of simulation and its application in the resolution of problems in complex industrial systems. Most problems of serious scale, be it an inventory problem, a production and distribution problem, a management of resources or process improvement, all real world problems require a mix of generic, data algorithmic and Ad-hoc solutions making the best of available information. We describe two projects in which analytical solutions were applied or contemplated. The first case study uses linear programming in the optimal allocation of advertising resources by a major internet service provider. The second study, in a series of projects, analyses options for the expansion of the production and distribution network of mining products, as part of a sensitive strategic business review. Using the examples, we make the case for the need of simulation in complex industrial problems where analytical solutions may be attempted but where the size and complexity of the problem forces a Monte Carlo approach.
2
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Linear programming models for optimal workload and batching in pick-and-pass warehousing systems

100%
TARCZYŃSKI G.
Operations Research and Decisions
|
2023
|
vol. 33
|
issue 3
141-158
EN
Pick-and-pass systems are a part of picker-to-parts order-picking systems and constitute a very common storage solution in cases where customer orders are usually small and need to be completed very quickly. As workers pick items in the zones connected by conveyor, their work needs to be coordinated. The paper presents MILP models that optimize the order-picking process. The first model uses information about expected demand for items to solve the storage location problem and balance the workload across zones. The task of the next model is order-batching and sequencing – two concepts are presented that meet different assumptions. The results of the exemplary tasks solved with the use of the proposed MILP models show that the total picking time of a set of orders can be reduced by about 35-45% in comparison with random policies. The paper presents an equation for the lower bound of a makespan. Recommendations about the number of zones that guarantee the required system efficiency are also introduced.
3
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The use of rank and optimisation methods in strategic management in higher education

100%
Ryńca R., Piórkowska N.
Operations Research and Decisions
|
2023
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vol. 33
|
issue 1
EN
The article presents proposals for a university management model supporting the process of strategic management at a university. The proposed model is based on the use of multi-criteria methods such as the 0–10 technique, object ranking, and optimisation methods – linear programming. The proposed solution integrates ranking and optimisation methods, the use of which may be helpful in the hands of managers in making management decisions. The proposed approach may also be helpful in developing a strategic scorecard, especially in the stage of formulating goals. It also enables the optimal selection of goals with the existing time constraints for the implementation of the strategy. The article presents a proposal for the use of the strategy implementation model and an example of its use. The strengths and weaknesses of the model were also indicated.
4
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Modified optimization model for selecting project risk response strategies

100%
MARCHWICKA E., KUCHTA D.
Operations Research and Decisions
|
2017
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vol. 27
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issue 2
77-90
EN
The authors present modifications of the optimization model for selecting project risk response strategies proposed by Zhang and Fan. The weaknesses of the original model has been identified and an improved model with the main suggestions has been proposed. The main improvement concerned the objective function. The modified model was tested using a real project in the electrical industry – engineering and construction of the main low voltage switchboard for a live fish carrier (Helix Q7000) in Norway. Project team members report that the analysis is time consuming but results are satisfying – the model allows more systematic and efficient risk management.
5
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Linear programming models for optimal workload and batching in pick-and-pass warehousing systems

100%
Tarczyński G.
Operations Research and Decisions
|
2023
|
vol. 33
|
issue 3
EN
Pick-and-pass systems are a part of picker-to-parts order-picking systems and constitute a very common storage solution in cases where customer orders are usually small and need to be completed very quickly. As workers pick items in the zones connected by conveyors, their work needs to be coordinated. The paper presents MILP models that optimize the order-picking process. The first model uses information about the expected demand for items to solve the storage location problem and balance the workload across zones. The task of the next model is order-batching and sequencing – two concepts are presented that meet different assumptions. The results of the exemplary tasks solved with the use of the proposed MILP models show that the total picking time of a set of orders can be reduced by about 35-45% in comparison with random policies. The paper presents an equation for the lower bound of a makespan. Recommendations about the number of zones that guarantee the required system efficiency are also introduced.
6
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An example to illustrate several aspects of optimization theory in Managerial Economics

88%
Lahiri S.
Managerial Economics
|
2021
|
vol. 22
|
issue 1
23-34
EN
We provide a single example that illustrates all aspects of linear, integer and dynamic programming, including such concepts such as value of perfect and imperfect information. Such problems, though extremely plausible and realistic are hardly ever discussed in managerial economics.
7
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Modele ekonometryczne jako narzędzie sterowania procesami technologicznymi

88%
Wołkowicz A.
Econometrics. Ekonometria. Advances in Applied Data Analytics
|
2015
|
issue 2 (48)
67-77
EN
This paper presents a proposal for process control applications based on econo-metric models. They are a tool which aim is to determine short-term forecasts, which are the basis to control the devices of production infrastructure. The article describes the application of the method of forecast errors corrective device in a real production process. Econometric models are presented: the exponential smoothing model and creeping trend adaptive model with harmonic scales. The calculations are used and the regression function is indicated by the linear programming problem. The method is presented on the example of classical tech-nological process used in the energy sector. The study indicates the possibility of another perspective on the control processes, not necessarily based on the existing methods of regu-lation. The idea of this study is to demonstrate the possibility of using econometrics in the industry.
8
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A linearisation approach to solving a non-linear shelf space allocation problem with multi-oriented capping in retail store and distribution centre

88%
Czerniachowska K., Hernes M., Lutosławski K.
Operations Research and Decisions
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2022
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vol. 32
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issue 4
EN
Shelf space is one of the essential resources in logistic decisions. Order picking is the most time-consuming and labourintensive of the distribution processes in distribution centres. Current research investigates the allocation of shelf space on a rack in a distribution centre and a retail store. The retail store, as well as the distribution centre, offers a large number of shelf storage locations. In this research, multi-orientated capping as a product of the rack allocation method is investigated. Capping allows additional product items to be placed on the rack. We show the linearisation technique with the help of which the models with capping could be linearised and, therefore, an optimal solution could be obtained. The computational experiments compare the quality of results obtained by non-linear and linear models. The proposed technique does not increase the complexity of the initial non-linear problem.
9
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On the binary classification problem in discriminant analysis using linear programming methods

88%
OLUSOLA M. O., ONYEAGU S. I.
Operations Research and Decisions
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2020
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vol. 30
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issue 1
119-130
EN
This paper is centred on a binary classification problem in which it is desired to assign a new object with multivariate features to one of two distinct populations as based on historical sets of samples from two populations. A linear discriminant analysis framework has been proposed, called the minimised sum of deviations by proportion (MSDP) to model the binary classification problem. In the MSDP formulation, the sum of the proportion of exterior deviations is minimised subject to the group separation constraints, the normalisation constraint, the upper bound constraints on proportions of exterior deviations and the sign unrestriction vis-à-vis the non-negativity constraints. The two-phase method in linear programming is adopted as a solution technique to generate the discriminant function. The decision rule on group-membership prediction is constructed using the apparent error rate. The performance of the MSDP has been compared with some existing linear discriminant models using a previously published dataset on road casualties. The MSDP model was more promising and well suited for the imbalanced dataset on road casualties.
10
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Irrigation of farm land under the EU Water Framework Directive

75%
Theuvsen L., Battermann H. W.
Problemy Rolnictwa Światowego
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2011
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vol. 11(26)
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issue 3
EN
With the Water Framework Directive (WFD), the European Union has established a legal framework for the protection of all aquatic ecological systems, including groundwater. This directive may have advantages for the water regime in ecologically sensitive areas but may also bring some economic disadvantages for farmers. The economic implications of the WFD for irrigated agriculture with regard to various scenarios and the implementation of alternative water policy measures are analysed. The results show that demand for irrigation water, farmers’ reactions with regard to operational and strategic decisions and income effects strongly depend on the water policy measures implemented.
11
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On the one-shot two-person zero-sum game in football from a penalty kicker’s perspective

75%
EKHOSUEHI V. U.
Operations Research and Decisions
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2018
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vol. 28
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issue 3
17-27
EN
A penalty kicker’s problem in football has been modelled. The study took into consideration different directions in which the ball can be struck and goalkeepers’ success at defending shots. The strategic form of the game that can be used to predict how the kicker should optimally randomise his strategies has been modelled as a non-linear game-theoretic problem from a professional kicker’s viewpoint. The equilibrium of the game (i.e., the pair of mutually optimal mixed strategies) was obtained from the game-theoretic problem by reducing it to a linear programming problem and the two-phase simplex method was adopted to solve this problem. The optimal solution to the game indicates that the kicker never chooses to kick the ball off target, to the goalpost or to the crossbar, but rather chooses to kick the ball in the opposite direction to the one where the goalkeeper is most likely to successfully defend from past history.
12
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ZASTOSOWANIE PROGRAMOWANIA MATEMATYCZNEGO DO WYBORU TRAS DOSTAW W SIECI DYSTRYBUCJI

63%
Liana M., Pisula T.
Metody Ilościowe w Badaniach Ekonomicznych
|
2014
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vol. 15
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issue 3
199-207
PL
Tematyka artykułu mieści się w zakresie logistyki dystrybucji i dotyczy planowania przewozów. Dla danej sieci dystrybucji można wyznaczyć zbiór opłacalnych tras dostaw. Problem decyzyjny sprowadza się do takiego wyboru tras z tego zbioru, żeby zminimalizować koszty transportu, załadunku i rozładunku. Do znalezienia optymalnego rozwiązania problemu zaproponowano programowanie matematyczne. W pracy przedstawiono liniowy model matematyczny zagadnienia. Model zawiera zarówno zmienne rzeczywiste, jak i zmienne binarne.
EN
The subject of article is within the scope of the distribution logistics and relates to transportation planning. For the given distribution network it is possible to appoint the set of cost-effective delivery routes. The decision problem comes down to such a choice of routes from this set to minimize transport, loading and unloading costs. The mathematical programming is proposed for finding an optimal solution of the problem. In the paper a linear mathematical model of the problem is presented. The model includes both real variables and binary variables.
13
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Metoda określania wielkości kontraktów na energię elektryczną

63%
GŁADYSZ B.
Operations Research and Decisions
|
2009
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vol. 19
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issue 3
19-26
PL
W artykule zaproponowano metodę określania wielkości kontraktów na rynku energii. Do wyznaczania wielkości kontraktów zaproponowano model binarnego programowania liniowego. Jako funkcję kryterium przyjęto minimalizację kosztów zakupu/sprzedaży energii, związanych z błędnym oszacowaniem zapotrzebowania na energię. W podanym przykładzie porównano koszty zakupu/sprzedaży energii w sytuacji, gdy prognoza jest oparta na modelu ekonometrycznym, wyznaczonym klasyczną metodą najmniejszych kwadratów oraz modelu wyznaczonym przedstawioną w artykule techniką. W obu modelach przyjęto ten sam zbiór zmiennych endogenicznych.
EN
The distributors of electrical energy have to manage supplies efficiently, in order to minimize the costs of its purchase/sale. In practice, the cost depends on the difference between the current energy demand and the contract value. In the literature, methods for forecasting demand and valuing energy contracts are thus developed in parallel. This paper presents a two-step method for calculating the value of an energy contract. In the first step independent factors, on which the demand for energy depends, are identified; for example: energy load in past periods, meteorological data and the type of day according to the calendar. In the second step binary linear programming is used to determine the value of the energy contract. The criterion used is the minimization of the cost of energy purchase/sale. An example is presented comparing the cost of an energy contract based on the proposed method to the cost based on regression forecasts.
14
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Accounting the scale and synergies in the DEA-analysis

51%
Novikov V., Shipulina L., Sapun O.
LogForum
|
2016
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vol. 12
|
issue 2
123-128
EN
Background: Proposed to take into account non-linear performance in terms of synergy when make DEA (Data Envelopment Analysis). The solution of the problem is done for interacting schools, which can be regarded as business clusters. The inputs and outputs are selected by them importance at author's opinion. However the technique does not change when taking into account other factors that have a numeric expression. Methods: It is proposed to reduce the number of the inputs and outputs to one input and one output using weighting factors. Thus the solution can be found by linear programming. The DEA algorithm is easily coded in Mathcad. Results: As a result, we get a vector of the effectiveness of each element of the business cluster, including stand-effective and super-efficient elements. Conclusions: Proposed a model of DEA taking into account the scale and synergies of a business cluster. This allows getting a performance rating against the collective interaction.
PL
Wstęp: Poddano analizie metodę nieliniową dla synergii przy zastosowaniu metody DEA (Data Envelopment Analysis). Rozwiązanie zostało zrealizowane dla współpracujących szkół, które mogą być traktowane, jako klastery biznesowe. Dane wejściowe i wyjściowe zostały wyselekcjonowane według ważności (w opinii autora). Aczkolwiek należy zaznaczyć, że metoda postępowania nie zmienia się przy analizie innych czynników, mogących być przedstawione w formie liczbowej. Metody: Zaproponowano redukcję liczby danych wejściowych i wyjściowych przy zastosowaniu współczynnika wagi. Następnie poszukano rozwiązania przy użyciu programowaniu liniowego. Algorytm DEA może być z łatwością zaimplementowany przy użyciu MATCAD. Wyniki: Otrzymano wektor efektywności każdego elementu klastera biznesowego, łącznie z elementami o stałej i bardo dużej efektywności. Wnioski: zaproponowano model DAE, uwzględniający skalę oraz synergię klastera biznesowego. Umożliwia to uszeregowanie zachowań wobec zbiorowych interakcji.
15
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Generowanie struktur harmonogramuz jednoczesnym rozwiązywaniem zadańpoziomu dolnego różnymi metodami

51%
Mirosław Dytczak M.
Zeszyty Naukowe Wyższej Szkoły Bankowej we Wrocławiu
|
2013
|
issue 2(34)
115-129
PL
W artykule rozważono zagadnienie identyfikacji najbardziej korzystnego uporządkowania operacji technologicznych przedsięwzięcia budowlanego. Problem jest trudny do rozwiązania z uwagi na zwykle bardzo dużą liczbę dopuszczalnych uporządkowań operacji. Przedstawiono też wielokryterialny model wykorzystujący wybrane dopuszczalne uporządkowania operacji przedsięwzięcia pozwalający na rozwiązanie tego zagadnienia. Do identyfikacji optymalnego z uwagi na czas i koszt realizacji przedsięwzięcia uporządkowania operacji wykorzystuje się dwuetapowe podejście. W pierwszym etapie są generowane dopuszczalne uporządkowania technologicznych operacji przedsięwzięcia przy wykorzystaniu symulacji Monte Carlo oraz algorytmów ewolucyjnych. Drugi etap służy przydzieleniu odpowiednich sposobów wykonania poszczególnym operacjom. Uwzględnia się przy tym ograniczoną dostępność zasobów odnawialnych w postaci zestawów środków technicznych niezbędnych do wykonania operacji poszczególnymi sposobami. Do optymalizacji wykorzystuje się programowanie liniowe (podejście MC-PL) oraz losowe przydziały sposobów wykonania operacji (podejście MC-MC). Zastosowane metody optymalizacji uzupełniają się, ponieważ pierwsza okazuje się bardziej skuteczna w przypadku przedsięwzięć o mniejszych, druga zaś – o większych rozmiarach.
EN
The problem of identification of the most beneficial order of technological operations of a complex construction project is dealt with in the paper. The problem is hard to solve because of a large number of feasible orders. A special approach is proposed to effectively solve the matter in question. The approach applies multi-criteria optimisation to project realisation based on selected feasible orders of operations. The paper proposes a two-step approach to determine the best, in terms of project execution time and cost, schedule of the project. Simulation is utilised in the first stage to determine feasible orders of project operations. Monte Carlo simulations and evolutionary algorithms are applied for generating of the operation orders. The second stage is devoted to identification of the best ways to perform different technological project operations, taking into account limited availability of required renewable resources – sets of technical measures. Different methods are applied with this regard. The MC-LP and MC-AE methods concern linear programming to allocate execution modes to operations, while MC-MC applies a random assignment with this regard. Utilised optimisation methods are complementary as they allow to identify optimal assignments of execution modes to project operations for both less and more complex construction projects.
16
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Optymalizacja przypisania zadania za pomocą liniowego narzędzia programującego PESBAT

51%
Yanch U., Wiechetek Ł.
Annales Universitatis Mariae Curie-Skłodowska, sectio H – Oeconomia
|
2018
|
vol. 52
|
issue 2
EN
The article presents task assignment problem and the role that modern linear programming tools may play in its solving. Task assignment problem is a case of the assignment problem, which is one of the fundamental combinatorial optimization problems. Its specific formulations can be found in logistics (e.g. driver assignment problem), computer science (e.g. memory management) and other fields of science and business. Various methods and algorithms have been created or adapted to solve the assignment problem, and modern linear programming and optimization tools like Microsoft Excel Solver, which contain implementations of these algorithms, provide a possibility to solve diverse cases of the assignment problem with minimum effort and time.The article addresses widely known task assignment problem in business, its sources and ways of solving or reducing its negative impact on business processes effectiveness. The paper contains also a general overview of modern linear programming tools that can be used for task assignment and describes Microsoft Excel Solver Add-in as a tool for business process optimization.The main part of the article is a presentation of VBA based optimization tool called PESBAT developed by the authors and the case of task assignment process optimization in the enterprise that offers photoanalytical services. Pilot use of a PESBAT tool showed that it allows reducing the time needed for task assignment, gives more balanced workload for employees but also indicated the optimization possibilities of other areas of described company, like route optimization and reports preparation.
PL
W artykule przedstawiono problem przypisywania zadań oraz rolę, jaką mogą odegrać w ich rozwiązywaniu nowoczesne narzędzia programowania liniowego. Problem przydziału zadań jest przypadkiem problemu przypisania, będącym jednym z podstawowych problemów optymalizacji kombinatorycznej. Jego specyficzne sformułowania można znaleźć w logistyce (np. problem przypisywania sterowników), informatyce (np. w zarządzaniu pamięcią) oraz innych dziedzinach nauki i biznesu. Opracowano lub zaadaptowano różne metody i algorytmy, aby rozwiązać problem przydziału, a nowoczesne narzędzia do programowania i optymalizacji liniowej, takie jak Microsoft Excel Solver, które zawierają implementację tych algorytmów, zapewniają możliwość rozwiązywania różnorodnych przypadków problemu przydziału przy minimalnym wysiłku i czasie.W opracowaniu szeroko omówiono znany problem przypisywania zadań w biznesie, jego źródła i sposoby rozwiązywania lub ograniczania jego negatywnego wpływu na efektywność procesów biznesowych. Praca zawiera również ogólny przegląd nowoczesnych narzędzi programowania liniowego, które można wykorzystać do przypisania zadań. Ponadto autorzy opisali dodatek Microsoft Solver Add-in jako narzędzie do optymalizacji procesów biznesowych.Główną częścią artykułu jest prezentacja opracowanego przez autorów narzędzia optymalizacyjnego VBA o nazwie PESBAT oraz przypadku optymalizacji procesu przydzielania zleceń w przedsiębiorstwie, które oferuje usługi fotoanalityczne. Pilotażowe wykorzystanie narzędzia PESBAT pokazało, że pozwala ono na skrócenie czasu potrzebnego na przypisanie zadań, zapewnia bardziej zrównoważony nakład pracy dla pracowników, ale także wskazało możliwości optymalizacji innych obszarów opisywanej firmy, takie jak optymalizacja trasy i przygotowanie raportów.
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SZACOWANIE KOSZTU SPRAWIEDLIWOŚCI ALOKACJI OBCIĄŻEŃ W SIECI DLA METODY OPTYMALIZACJI UPORZĄDKOWANEJ ŚREDNIEJ WAŻONEJ

45%
Zalewski G., Ogryczak W.
Metody Ilościowe w Badaniach Ekonomicznych
|
2015
|
vol. 16
|
issue 4
230-241
PL
Jednym z wielu problemów podczas wymiarowania sieci telekomunikacyjnych jest optymalizacja przepływów zapotrzebowań między zadanymi węzłami. Jednym ze sposobów wykorzystywanych do tego celu jest formułowanie zadania programowania liniowego. W niniejszej pracy skupiono się na optymalizacji ulokowania przepływów na danych ścieżkach w grafie nieskierowanym. Dodatkowo ważnym elementem zadania jest fakt, że ścieżki dzielą między sobą ograniczone zasoby przepustowości, co sprawia zaistnienie rzeczywistego problemu decyzyjnego. Dla tak sformułowanego problemu wykorzystano formułę krawędź-ścieżka programowania liniowego oraz implementację zadania w standardzie AMPL. W pracy oszacowano koszt rozwiązania sprawiedliwego dla modelu OWA (Ordered Weighted Averaging) w porównaniu do rozwiązania maksymalizującego przepływy na ścieżkach oraz do rozwiązania modelu MMF (maximin fairness). Efektem końcowym pracy jest przedstawienie wyników oraz podsumowanie analizy otrzymanych rozwiązań na bazie danych przykładowych, stanowiących odniesienie do sieci telekomunikacyjnej szkieletowej Polski, gdzie głównym miernikiem jest różnica wartości funkcji celu dla wymienionych metod sprawiedliwej optymalizacji oraz rozwiązania maksymalizującego przepływ całkowity.
EN
An important problem when designing a telecommunication network is to optimize the flow demands at the network between pre-defined nodes. One of the solutions used for this purpose is to formulate the linear programming. In this paper we focus on the optimization of locating the data flow path in an undirected network. It provides an actual decision-making problem. For such a problem the link-path formula has been chosen. Problem also has brought to linear programming and implemented in AMPL standard. The study estimated the price of fairness for the considered model OWA (Ordered Weighted Averaging) compared to solve maximizing flows on the paths and to solve the model MMF (Maximin fairness). The final effect of the work is to present the results and a summary of the analysis, obtained solutions based on sample data by reference to the telecommunication network which in this case was the backbone Polish net. The main measure is the difference between the value of the objective function for these fair methods and solutions maximizing total flow.
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Metody zarządzania zasobami na przykładzie służby zdrowia

45%
UZIAŁKO J., RADOSIŃSKI E.
Operations Research and Decisions
|
2009
|
vol. 19
|
issue 1
121-142
PL
W artykule przedstawiono i zanalizowano problem zarządzania zasobami w służbie zdrowia. Omówiono podstawowe zagadnienia w procesie alokacji zasobów medycznych. Zaprezentowano przykłady zastosowania wybranych metod: programowania matematycznego (liniowego, całkowitoliczbowego, celowego, sieciowego), teorii kolejek, modelowania symulacyjnego, systemów hybrydowych oraz standardowych metod kosztowo-efektywnościowych do analizy zagadnień, związanych z podziałem zasobów w systemach opieki zdrowotnej. Przedyskutowano użyteczność tych metod do rozwiązywania szczegółowych problemów dotyczących zarządzania zasobami medycznymi.
EN
Various issues referring to general problems of resource allocation in the area of healthcare were discussed in the article. Fundamental questions regarding the process of allocating healthcare resources were pointed out. The topics were presented according to the categories of methods used to potentially solve these problems. The following approaches were considered: chosen methods of mathematical programming, queuing theory, simulation, hybrid algorithms combining, among others, artificial intelligence and other techniques, as well as standard cost-effectiveness methods. Such methods were applied to the following problems: analyzing the current state of health care units and presenting proposals of changes to such systems. The modifications suggested referred to: allocation of material resources, planning the work schedules of medical personnel and patient admission. The question of determining the effectiveness of various medical strategies was also discussed. The article clearly underlined the importance and complexity of the problem of managing healthcare resources.
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