Wyniki wyszukiwania - BazTech

1

Optimising the management of arriving baggage at a Kuwait Airways passenger terminal using mathematical programming and simulation

Abdullah Ahmad A., Al-Sultan Ahmad T., Alsaber Ahmad

Operations Research and Decisions

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2024

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Vol. 34, No. 1

1--16

EN

Handling luggage systems is a critical component of a passenger terminal’s operations. The proposed study attempts to find the optimal solution for a manually operated terminal concerning the luggage offloading process from arrival flights carried by a limited number of ground handling agents. Handling agents start the offloading process from the aircraft to the cargo luggage containers carried by a cargo car that will take the containers’ trolleys to the cargo area to offload them into the reserved luggage belt carousel. This study aims to improve airport service quality by minimizing the baggage handling process time for arrival flights which leads to minimizing passenger waiting time in the baggage claim area. We proposed both a deterministic and stochastic approach. The integer programming method is provided to minimize the total number of flights assigned to the belt carousel under the realistic constraint of minimizing the luggage load on each belt carousel. Simulation tools were used so that the offloading process could be modeled to study the effects of various parameters such as the number of ground handling agents for different flights with different amounts of luggage.

2

An integrated modelling approach for an optimal location of warehouses in the defence industry organisation

Bayrakcı Melda Gelibolu, Baykoç Ömer Faruk

Operations Research and Decisions

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2023

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Vol. 33, No. 2

35--52

EN

Countries’ defence industries are the leading indicator of their global power. The warehouse is the place where the materials are kept until the customer order arrives so that the companies are viable and can respond appropriately to internal/external customer demands. In this regard, warehouse location plays a vital role in the defence industry in terms of storage options with increased flexibility, a simplified supply chain with cost management and optimal positioning according to deployment locations. In this study, the decision on the location of warehouses for logistic support during the warranty period of military vehicles manufactured and supplied to the armed forces by a defence company was made. It is aimed to propose the best solution to a real-life problem with high complexity, containing many data and constraints. In this context, the criteria that are thought to be most relevant to this problem have been determined by taking expert opinions. Having determined the order of importance of the requirements by the analytical hierarchy process (AHP) with the Super Decisions V 2.10, their weights were included as a coefficient of the objective function in the goal programming (GP) model. As a result of solving the GP model using GAMS (general algebraic modelling system), it was decided to select the warehouses that provided the optimal results among the alternative warehouse locations in 9 different locations. Furthermore, to see the impact of changes in criterion weights, sensitivity analysis has also been included. The significance of this research lies within the integrated usage of AHP and GP in the defence industry when determining warehouse locations by the experts’ opinions. With this study, not only a solution strategy was developed, but also a basis for the warehouse location decision in the defence industry projects already signed or to be signed was given.

3

Method of electrical equipment assembly rescheduling for assembly lines without intermediate buffers

Magiera Marek

Przegląd Elektrotechniczny

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2021

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R. 97, nr 1

95--99

EN

The method presented herein is used to build new schedules, particularly when it is necessary to modify previous schedules for assembly operations. It is used to include new, urgent orders in a schedule, as well as if at least one machine malfunctions. This method applies to assembly of electrical equipment in a one-way assembly line without parallel machines and without local storages. Due to lack of intermediate buffers in the assembly line setup, two cases were taken into account: possibility of the machines being blocked by products awaiting further operations and nowait scheduling. The assembly schedules concerning these cases were compared by conducting computational experiments. These experiments were conducted on constructed integer programming task models.

PL

Przedstawiona metoda służy do budowy nowych harmonogramów, zwłaszcza gdy jest konieczne dokonanie zmian w uprzednich uszeregowaniach operacji montażowych. Jest ona stosowana w celu uwzględnienia w harmonogramie nowych, pilnych zleceń, a także w przypadku awarii co najmniej jednej maszyny. Metoda dotyczy montażu sprzętu elektrycznego w jednokierunkowej linii montażowej bez maszyn równoległych oraz bez lokalnych magazynów. W związku z brakiem buforów międzyoperacyjnych w konfiguracji linii montażowej uwzględniono dwa przypadki: możliwość blokowania maszyn przez produkty oczekujące na wykonanie kolejnych operacji oraz szeregowanie „bez czekania”. Harmonogramy montażu dotyczące tych przypadków zostały porównane za pomocą przeprowadzonych eksperymentów obliczeniowych. Eksperymenty te przeprowadzono na zbudowanych modelach zadań programowania całkowitoliczbowego.

4

A novel approach to optimize the maintenance strategies: a case in the hydroelectric power plant

Özcan Evrencan, Yumuşak Rabia, Eren Tamer

Eksploatacja i Niezawodność

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2021

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Vol. 23, no. 2

324--337

EN

Countries need to develop sustainable energy policies based on the principles of environmental sensitivity, reliability, efficiency, economy and uninterrupted service and to maintain their energy supply in order to increase their global competitiveness. In addition to this impact of sustainable energy supply on the global world, maintenance processes in power plants require high costs due to allocated time, materials and labor, and generation loss. Thus, the maintenance needs to be managed within a system. This makes analytical and feasible maintenance planning a necessity in power plants. In this context, this study focuses on maintenance strategy optimization which is the first phase of maintenance planning for one of the large-scale hydroelectric power plants with a direct effect on Turkey's energy supply security with its one fifth share in total generation. In this study, a new model is proposed for the maintenance strategy optimization problem considering the multi-objective and multicriteria structure of hydroelectric power plants with hundreds of complex equipment and the direct effect of these equipment on uninterrupted and cost-effective electricity generation. In the model, two multi-criteria decision-making methods, AHP and COPRAS methods, are integrated with integer programming method and optimal maintenance strategies are obtained for 571 equipment.

5

Hierarchical method of rescheduling for assembly lines with intermediate buffers

Magiera Marek

Technologia i Automatyzacja Montażu

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2020

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nr 2

4--8

EN

A method of scheduling assembly in flexible assembly lines without parallel machines is presented. The method applies to lines fitted with intermediate buffers with limited capacities. The developed method is distinguished by the possibility of rescheduling. This is very significant in the case of a need to provide for new, urgent orders, as well as machine failures. The first level of the method concerns balancing the load of the assembly machines. Starting times of individual operations are determined at the second level of the method. Integer programming was used to solve the tasks allocated to both levels of the method. The results of computational experiments regarding the method are described.

PL

Zaprezentowano metodę budowy harmonogramów montażu w elastycznych liniach montażowych bez maszyn równoległych. Metoda dotyczy linii wyposażonych w bufory międzyoperacyjne o ograniczonych pojemnościach. Opracowaną metodę wyróżnia możliwość reharmonogramowania. Ma to duże znaczenie w przypadku konieczności uwzględnienia nowych, pilnych zleceń, a także awarii maszyn. Pierwszy poziom metody dotyczy równoważenia obciążeń maszyn montażowych. Wyznaczenie czasów rozpoczęcia wykonywania poszczególnych operacji dokonywane jest na poziomie drugim metody. Do rozwiązania zadań przyporządkowanych obu poziomom metody zastosowano programowanie całko-witoliczbowe. Zamieszczono wyniki eksperymentów obliczeniowych dotyczących metody.

6

An optimum scheduling method for multi-option product flows through production lineswithout intermediate buffers

Magiera Marek

Management and Production Engineering Review

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2020

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Vol. 11, No. 1

86--94

EN

The presented method is constructed for optimum scheduling in production lines with parallel machines and without intermediate buffers. The production system simultaneously performs operations on various types of products. Multi-option products were taken into account – products of a given type may differ in terms of details. This allows providing for individual requirements of the customers. The one-level approach to scheduling for multioption products is presented. The integer programming is used in the method – optimum solutions are determined: the shortest schedules for multi-option products. Due to the lack of the intermediate buffers, two possibilities are taken into account: no-wait scheduling, possibility of the machines being blocked by products awaiting further operations. These two types of organizing the flow through the production line were compared using computational experiments, the results of which are presented in the paper.

7

New models and algorithms for RNA pseudoknot order assignment

Zok Tomasz, Badura Jan, Swat Sylwester, Figurski Kacper, Popenda Mariusz, Antczak Maciej

International Journal of Applied Mathematics and Computer Science

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2020

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Vol. 30, no. 2

315--324

EN

The pseudoknot is a specific motif of the RNA structure that highly influences the overall shape and stability of a molecule. It occurs when nucleotides of two disjoint single-stranded fragments of the same chain, separated by a helical fragment, interact with each other and form base pairs. Pseudoknots are characterized by great topological diversity, and their systematic description is still a challenge. In our previous work, we have introduced the pseudoknot order: a new coefficient representing the topological complexity of the pseudoknotted RNA structure. It is defined as the minimum number of base pair set decompositions, aimed to obtain the unknotted RNA structure. We have suggested how it can be useful in the interpretation and understanding of a hierarchy of RNA folding. However, it is not trivial to unambiguously identify pseudoknots and determine their orders in an RNA structure. Therefore, since the introduction of this coefficient, we have worked on the method to reliably assign pseudoknot orders in correspondence to the mechanisms that control the biological process leading to their formation in the molecule. Here, we introduce a novel graph coloring-based model for the problem of pseudoknot order assignment. We show a specialized heuristic operating on the proposed model and an alternative integer programming algorithm. The performance of both approaches is compared with that of state-of-the-art algorithms which so far have been most efficient in solving the problem in question. We summarize the results of computational experiments that evaluate our new methods in terms of classification quality on a representative data set originating from the non-redundant RNA 3D structure repository.

8

Optimization of underground mine access layout and production scheduling

Hou Jie, Li Guoqing, Hu Nailian

Gospodarka Surowcami Mineralnymi

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2020

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T. 36, z. 2

87--108

EN

Optimization in mine planning could improve the economic benefit for mining companies. The main optimization contents in an underground mine includes stope layout, access layout and production scheduling. It is common to optimize each part sequentially, where optimal results from one phase are treated as the input for the next phase. The production schedule is based on the mining design. Access layout plays an important role in determining the connection relationships between stopes. This paper proposes a shortest-path search algorithm to design a network that automatically connects each stope. Access layout optimization is treated as a network flow problem. Stopes are viewed as nodes, and the roads between the stopes are regarded as edges. Moreover, the decline location influences the ore transport paths and haul distances. Tree diagrams of the ore transportation path are analyzed when each stope location is treated as an alternative decline location. The optimal decline location is chosen by an enumeration method. Then, Integer Programming (IP) is used to optimize the production scheduling process and maximize the Net Present Value (NPV). The extension sequence of access excavation and stope extraction is taken into account in the optimization model to balance access development and stope mining. These optimization models are validated in an application involving a hypothetical gold deposit, and the results demonstrate that the new approach can provide a more realistic solution compared with those of traditional approaches.

PL

Optymalizacja w planowaniu kopalni może poprawić korzyści gospodarcze dla przedsiębiorstw górniczych. Główna część optymalizacji w kopalni podziemnej obejmuje układ wyrobisk eksploatacyjnych, schemat udostepnienia i harmonogram wydobycia. Zazwyczaj każdy etap optymalizowany jest sekwencyjnie, gdzie optymalne wyniki z jednej fazy są traktowane jako dane wejściowe do następnej fazy. Harmonogram produkcji opiera się na projekcie górniczym. Struktura udostępnienia odgrywa ważną rolę w określaniu połączeń pomiędzy przodkami eksploatacyjnymi. Ten artykuł proponuje algorytm wyszukiwania najkrótszej ścieżki, aby zaprojektować sieć, która automatycznie łączy każdy przodek. Optymalizacja struktury udostępnienia jest traktowana jako problem przepływu w sieci. Przodki są traktowane jako węzły, a drogi pomiędzy nimi jako krawędzie. Ponadto lokalizacja upadowej udostępniającej wpływa na drogi transportu rudy i odległości odstawy. Analiza ścieżek drzew zdarzeń odbywa się przy założeniu alternatywnych lokalizacji upadowych. Optymalna lokalizacja upadowej jest wybierana metodą wyliczania. Następnie, za pomocą programowania zintegrowanego (Integer Programming – IP) optymalizuje się proces planowania produkcji i maksymalizacji wartości bieżącej netto (NPV).Rozwinięty układ wyrobisk udostępniających i eksploatacyjnych jest uwzględniany w modelu optymalizacji do zbilansowania udostępnienia i eksploatacji złoża. Te modele optymalizacji są walidowane w aplikacji uwzględniającej hipotetyczne złoże rud złota, której wyniki pokazują, że nowe podejście może dostarczyć bardziej realistyczne rozwiązanie w porównaniu z tradycyjnymi metodami.

9

Mimimizing the cost of using tractors at agricultural operations

Zaynagabdinov Rishat, Gabitov Ildar, Bakiev Ilshat, Gafurov Ildar, Kostarev Konstantin

Diagnostyka

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2020

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Vol. 21, No. 2

41--49

EN

The paper shows the economic efficiency of the optimal use of technology in crop production. A totally new model has been developed ,that allows planning the operation of each tractor individually, as well as an integer programming method with Boolean variables based on the formation of a lexicographic sequence. The paper shows the calculation according to the optimization criterion of the minimum duration of the work. The developed method of integer programming is original because it allows to solve problems typical of agricultural planning. For this, the authors derived a formula for the formation of any member of the lexicographic sequence and developed the AgroMaster + computer program, which also carries out the search for the optimal solution using the method of truncated exhaustive search. Due to optimal planning, the total duration of agricultural operations is reduced by 1.7 times compared to their actual duration. The cost of additional products received per 1 moto-hour is 7.3 dollars. The testing the results of studies in one of the farms of the Republic of Bashkortostan showed the possibility of practical application of the above developments for optimal planning of tractors in any agricultural enterprises.

10

Bi-objective routing in a dynamic network: An application to maritime logistics

Maskooki Alaleh, Nikulin Yury

Control and Cybernetics

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2020

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Vol. 49, No. 2

211--232

EN

A bi-objectiveMILP model for optimal routing in a dynamic network with moving targets (nodes) is developed, where all targets are not necessarily visited. Hence, our problem extends the moving target travelling salesman problem. The two objectives aim at finding the sequence of targets visited in a given time horizon by minimizing the total travel distance and maximizing the number of targets visited. Due to a huge number of binary variables, such a problem often becomes intractable in the real life cases. To reduce the computational burden, we introduce a measure of traffic density, based on which we propose a time horizon splitting heuristics. In a real-world case study of greenhouse gas emissions control, using Automatic Identification System data related to the locations of ships navigating in the Gulf of Finland, we evaluate the performance of the proposed method. Different splitting scenarios are analysed numerically. Even in the cases of a moderate scale, the results show that near-efficient values for the two objectives can be obtained by our splitting approach with a drastic decrease in computational time compared to the exact MILP method. A linear value function is introduced to compare the Pareto solutions obtained by different splitting scenarios. Given our results, we expect that the present study is valuable in logistic applications, specifically maritime management services and autonomous navigation.

11

Pipe-lining Dynamic Programming Processes in Order to Synchronize Energy Production and Consumption

Bendali Fariha, Quilliot Alain, Mole Kamga Eloise, Mailfert Jean, Toussaint Hélène

Annals of Computer Science and Information Systems

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2020

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Vol. 21

303--306

EN

Synchronizing heterogeneous processes remains a difficult issue in Scheduling area. Related ILP models are in trouble, because of large gaps induced by rational relaxation. We propose here a pipe-line decomposition of a dynamic programming process for energy production and consumption scheduling, and describe the way related sub-processes interact in order to achieve efficient synchronization.

12

An Experimental Study on Symmetry Breaking Constraints Impact for the One Dimensional Bin-Packing Problem

Hadj Salem Khadija, Kieffer Yann

Annals of Computer Science and Information Systems

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2020

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Vol. 21

317--326

EN

We consider the classical One-Dimensional Bin Packing Problem (1D-BPP), an NP-hard optimization problem, where, a set of weighted items has to be packed into one or more identical capacitated bins. We give an experimental study on using symmetry breaking constraints for strengthening the classical integer linear programming proposed to optimally solve this problem. Our computational experiments are conducted on the data-set found in BPPLib and the results have confirmed the theoretical results.

13

Wpływ sposobu doboru drzew rountingowych na przepustowość ruchową multicastowych sieci radiowych

Nowak Mateusz, Ostrowski Bartłomiej, Kalesnikau Ilya

Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne

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2019

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nr 7

709--712, CD

PL

W artykule rozpatrujemy problem maksymalizacji przepustowości ruchowej kratowych sieci radiowych z pakietowym ruchem multicastowym obsługiwanym w trybie wielodostępu czasowego TDMA. W tego typu sieciach pakiety kierowane są od źródeł do ujść po drogach określonych za pomocą drzewa routingowego. W przedstawionych rozważaniach, zilustrowanych obliczeniowo, badamy, jak rożne sposoby doboru drzew routingowych wpływają na przepustowość ruchową sieci. Badania takie mogą być pomocne przy konfigurowaniu sieci sensorowych.

EN

In this paper we consider an optimization problem of maximizing traffic throughput in wireless mesh networks with multicast packet traffic. In such networks the way packets are transmitted from sources to destinations is controlled by means of routing trees. In the presented numerical study we examine impact of different routing trees selection methods on network’s traffic throughput efficiency. The considerations can be helpful in wireless sensor networks operation.

14

Flexible measure in the presence of the partial input to output impacts process

Shakouri Rita, Salahi Maziar, Kordrostami Sohrab, Wu Jie

Operations Research and Decisions

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2019

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Vol. 29, No. 3

77--98

EN

Precise recognition of the nonparametric measurement approach in the production process and proper application of accurate techniques to categorise the variables play a key role in the process of improving performance of decision-making units (DMUs). The classical data envelopment analysis (DEA) models require that the status of all inputs and outputs measures be precisely specified in advance. However, there are situations where a performance measure can play input role for some DMUs and output role for the others. This paper introduces an approach to determine the situation of such flexibility where in the presence of resource sharing among subunits, the partial input will impact output in DEA. As a result, DMUs have a fair evaluation when compared to each other. Likewise, the maximum improvement is obtained in aggregate efficiency due to partial input to output impacts. The proposed approach is applied to a set of real data collected from 30 branches of an Iranian bank.

15

Simultaneous integrated optimization for underground mine planning: application and risk analysis of geological uncertainty in a gold deposit

Hou Jie, Li Guoqing, Hu Nailian, Wang Hao

Gospodarka Surowcami Mineralnymi

|

2019

|

T. 35, z. 2

153--174

EN

The main optimized objects in underground mines include: stope layout, access layout and production scheduling. It is common to optimize each component sequentially, where optimal results from one phase are regarded as the input data for the next phase. Numerous methods have been developed and implemented to achieve the optimal solution for each component. In fact, the interaction between different phases is ignored in the tradition optimization models which only get the suboptimal solution compared to the integrated optimization model. This paper proposes a simultaneous integrated optimization model to optimize the three components at the same time. The model not only optimizes the mining layout to maximize the Net Present Value (NPV), but also considers the extension sequence of stope extraction and access excavation. The production capacity and ore quality requirement are also taken into account to keep the mining process stable in all mine life. The model is validated to a gold deposit in China. A two-dimensional block model is built to do the resource estimation due to the clear boundary of the hanging wall and footwall. The thickness and accumulation of each block is estimated by Ordinary Kriging (OK). In addition, the conditional simulation method is utilized to generate a series of orebodies with equal possibility. The optimal solution of optimization model is carried out on each simulated orebody to evaluate the influence of geological uncertainty on the optimal mining design and production scheduling. The risk of grade uncertainty is quantified by the possibility of obtaining the expected NPV. The results indicate that the optimization model has the ability to produce an optimal solution that has a good performance under the uncertainty of grade variability.

PL

Główne optymalizowane obiekty w kopalniach podziemnych to parametry struktury przodka wybierkowego, optymalnego udostępnienia oraz planowanie robót górniczych. Powszechne jest optymalizowanie każdego komponentu po kolei, przy czym optymalne wyniki jednej fazy są uważane za dane wejściowe dla następnej. Opracowano i wdrożono wiele metod w celu uzyskania optymalnego rozwiązania dla każdego komponentu. W rzeczywistości interakcja między różnymi fazami jest ignorowana w tradycyjnych modelach optymalizacji, które prowadzą do nieoptymalnych rozwiązań w porównaniu ze zintegrowanym modelem optymalizacji. Niniejszy artykuł przedstawia zintegrowany model optymalizacji optymalizujący trzy komponenty w tym samym czasie. Model nie tylko optymalizuje układ wydobywczy, aby zmaksymalizować wartość bieżącą netto (NPV), ale także uwzględnia parametry przodka wybierkowego oraz wkopu udostępniającego złoże. Aby utrzymać proces wydobycia na stałym poziomie przez cały czas trwania eksploatacji, pod uwagę brane są również zdolności produkcyjne oraz wymagania dotyczące jakości rudy. Omawiany model jest opracowany na potrzeby złoża złota w Chinach. Powstały dwuwymiarowy model blokowy do oszacowania zasobów ze względu na wyraźną granicę między skrzydłem wiszącym a spągowym. Grubość i akumulacja każdego bloku jest szacowana za pomocą krigingu zwyczajnego (OK). Dodatkowo wykorzystywana jest warunkowa symulacja w celu generowania szeregu złóż rudy. Optymalny model optymalizacji jest przeprowadzany na każdym symulowanym złożu w celu oceny wpływu niepewności geologicznej na optymalne planowanie robót górniczych i produkcji. Ryzyko odnośnie do niepewności jakości złoża jest kwantyfikowane przez możliwość uzyskania oczekiwanej wartości bieżącej netto (NPV). Wyniki wskazują, że model optymalizacji ma zdolność do tworzenia optymalnego rozwiązania w warunkach niepewności.

16

A novel integer linear programming model for routing and spectrum assignment in optical networks

Hadhbi Youssouf, Kerivin Hervé, Wagler Annegret

Annals of Computer Science and Information Systems

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2019

|

Vol. 18

127--134

EN

The routing and spectrum assignment problem is an NP-hard problem that receives increasing attention during the last years. Existing integer linear programming models for the problem are either very complex and suffer from tractability issues or are simplified and incomplete so that they can optimize only some objective functions. The majority of models uses edge-path formulations where variables are associated with all possible routing paths so that the number of variables grows exponentially with the size of the instance. An alternative is to use edge-node formulations that allow to devise compact models where the number of variables grows only polynomially with the size of the instance. However, all known edge-node formulations are incomplete as their feasible region is a superset of all feasible solutions of the problem and can, thus, handle only some objective functions. Our contribution is to provide the first complete edge-node formulation for the routing and spectrum assignment problem which leads to a tractable integer linear programming model. Indeed, computational results show that our complete model is competitive with incomplete models as we can solve instances of the RSA problem larger than instances known in the literature to optimality within reasonable time and w.r.t. several objective functions. We further devise some directions of future research.

17

A Minimum set-cover problem with several constraints

Dörpinghaus Jens, Düing Carsten, Weil Vera

Annals of Computer Science and Information Systems

|

2019

|

Vol. 18

115--122

EN

A lot of problems in natural language processing can be interpreted using structures from discrete mathematics. In this paper we will discuss the search query and topic finding problem using a generic context-based approach. This problem can be described as a a Minimum Set Cover Problem with several constraints. The goal is to find a minimum covering of documents with the given context for a fixed weight function. The aim of this problem reformulation is a deeper understanding of both the hierarchical problem using union and cut as well as the non-hierarchical problem using the union. We thus choose a modeling using bipartite graphs and suggest a novel reformulation using an integer linear program as well as novel graph-theoretic approaches.

18

Monolityczna a hierarchiczna metoda harmonogramowania montażu wielowariantowych produktów – porównanie dwóch koncepcji

Magiera M.

Technologia i Automatyzacja Montażu

|

2018

|

nr 3

13--18

PL

W artykule porównano dwie metody przeznaczone do budowy najkrótszych harmonogramów montażu. Dotyczą one linii montażowych z maszynami równoległymi, wyposażonymi w bufory między operacyjne o ograniczonych pojemnościach. Uwzględniono sztywne, a także alternatywne marszruty montażu. Metody przeznaczone są dla produktów wielowariantowych – każdy z produktów określonego typu może posiadać wyróżniające go cechy, uwzględniające wymagania odbiorców. W przypadku przedstawionej w artykule metody hierarchicznej najpierw dokonywany jest przydział operacji do maszyn, a następnie wyznaczane są czasy rozpoczęcia danych operacji. Zastosowano programowanie całkowitoliczbowe – poszczególnym poziomom metody przyporządkowano liniowe modele matematyczne zadań programowania całkowitoliczbowego. Zaprezentowaną w pracy metodę hierarchiczną porównano z metodą monolityczną, dzięki której operacje równocześnie rozdzielane są w przestrzeni i w czasie. W rezultacie zastosowaniu programowania całkowitoliczbowego metoda monolityczna umożliwia wyznaczanie optymalnych harmonogramów montażu. Przedstawiono wyniki eksperymentów obliczeniowych, których celem było porównanie obu koncepcji wyznaczania harmonogramu montażu.

EN

The monolithic and the hierarchical method are compared in the paper. They are intended to build as short assembly schedules as possible. The methods are constructed for assembly lines with parallel machines and with intermediate buffers. A fixed and an alternative assembly routes are regarded. The most important, distinctive feature of these methods, is that they are provided for multi-option products. Assembly of various products in different variants is the reply to the contemporary challenges faced by the manufacturers, who try to satisfy the demands of individual customers. The hierarchical method consists of two levels. The first level of the hierarchical method is connected with balancing machine workloads. The task scheduling is accomplished on the second level of the method. The mathematical models of integer programming tasks were built for its specific levels. The presented in the paper hierarchical method was compared with the monolithic method. The problems of balancing machine workloads and scheduling are solved simultaneously using the monolithic method. Using integer programming and the monolithic concept allowed to determine optimum solutions. The results of computational experiments with the proposed approaches for scheduling for assembly of multi-option products are presented.

19

An integer optimization model and algorithms to support the cost-revenue study and provisory designing warehouses or other storage objects

Miatselski M., Staruch B., Staruch B.

Technical Sciences / University of Warmia and Mazury in Olsztyn

|

2018

|

nr 21(4)

257--269

EN

An optimization model for the cost–revenue study at the stage of system analysis and preliminary designs of storage objects such as warehouses, containers, packs and similar objects are developed. Our assumptions motivated by warehouses design lead us to a nonlinear integer optimization problem with the only basic constraint. We present algorithmic methods for obtaining the exact solution to the general problem with emphasizing the special case when both the objective and the constraint functions are increasing. The results of the paper may be used in developing software tools intended for supporting designers.

20

A no-wait scheduling method for assembly operations concerning multi-option electric devices

Magiera M.

Przegląd Elektrotechniczny

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2018

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R. 94, nr 4

187--190

EN

The monolithic method of no-wait scheduling is presented. The individual requirements of recipients of the electric devices are regarded. The method is for assembly lines with parallel machines, without intermediate buffers. The mathematical models of integer programming are constructed for this configuration of assembly lines – for no-wait scheduling. The results of computational experiments with the proposed method are presented – fixed and alternative assembly routes are compared, among others.

PL

Przedstawiono monolityczną metodę szeregowania operacji montażowych dotyczących sprzętu elektrycznego uwzgledniającego indywidualne wymagania odbiorców. Metodę zbudowano dla linii montażowych z maszynami równoległymi, bez buforów międzyoperacyjnych. Skonstruowane modele matematyczne zadań programowania całkowitoliczbowego, w których uwzględniono opisane konfiguracje linii montażowych, przeznaczone są do budowy harmonogramów montażu zgodnie z ideą szeregowania „bez czekania”. Zamieszczono wyniki eksperymentów obliczeniowych – porównano m.in. dwie różne organizacje przepływów produktów dotyczące sztywnych i alternatywnych marszrut montażu.