Wyniki wyszukiwania - BazTech

1

A linearisation approach to solving a non-linear shelf space allocation problem with multi-oriented capping in retail store and distribution centre

Czerniachowska Kateryna, Hernes Marcin, Lutosławski Krzysztof

Operations Research and Decisions

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2022

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Vol. 32, No. 4

33--56

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.

2

Global optimal vessel capacity for LNG production and transportation

Igboanusi Cninemerem, Amuji Harrison Obiora, Onukwube Obioma G., Chikadibia Nwosu Azuwueze

Journal of Sustainable Development of Transport and Logistics

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2022

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Vol. 7, No. 1

82--89

EN

In this paper, developed a linear programming model to determine the volume of vessels that will give an optimal return on investment. The solution to the developed model was carried out using the Interior Point algorithm with the help of the MATLAB package. The analysis observed that the production and transporting of the LNG with a vessel of capacity 178,5006m3 would give an optimal profit of 633,640 million USD. And from the results of the analysis, we observed that the decision to take the maximum modern capacity instead of lower capacities yields the highest profit.

3

Optymalizacja kosztów transportu gazu skroplonego LNG pod względem lokalizacji magazynów na przykładzie Polski

Popławski Tomasz, Kurkowski Bartosz

Rynek Energii

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2021

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Nr 4

3--8

PL

Wielu ekspertów zarówno z Polski jak i UE jednoznacznie stwierdza, że Gazociąg Nordstream 2 zmniejsza bezpieczeństwo gazowe zarówno Polski jaki i państw z Europy środkowowschodniej. W związku z tym konieczne są różne przedsięwzięcia w celu dywersyfikacji dostaw gazu do Polski. Przy istniejącej i wciąż rozwijającej się infrastrukturze drogowej oraz kolejowej, jak również w obliczu istnienia terminali do odbioru gazu w Świnoujściu i Gdańsku, jednym z możliwych działań w tym kierunku jest budowa nowych magazynów lub rozbudowa starych w taki sposób, aby można było przewozić i przechowywać tam skroplony gaz LNG. Jednak, aby przedsięwzięcie to było opłacalne, lokalizacje tych magazynów muszą tak zostać dobrane, aby zminimalizować przyszłe koszty transportowe. W niniejszym artykule zaproponowano metodę opartą o programowanie liniowe, która pozwala na optymalną alokację magazynów LNG. Jej innowacyjnym względem istniejących metod elementem jest dynamicznie aktualizująca się waga dostawcy, w zależności od przypisanych do niego odbiorców. Dla zaprezentowanego przykładu zaproponowana metoda pozwoliła na zmniejszenie kosztów drogowych o ponad 25%.

EN

Many experts from both Poland and the EU clearly state that the Nordstream 2 gas pipeline reduces gas safety both in Poland and in Central and Eastern European countries. With the existing and still developing road and rail infrastructure, as well as the gas receiving terminals in Świnoujście and Gdańsk, one of the possible actions is the construction of new warehouses or expansion of old ones so that LNG can be transported and stored there. However, for this venture to be profitable, the locations of these warehouses must be selected to minimize future transport costs. This article proposes a method based on linear programming that allows for the optimal allocation of LNG storage facilities. Its innovative element compared to the existing methods is the dynamically updating weight of the supplier, depending on the recipients assigned to it. For the example shown, the proposed method allowed to reduce road costs by more than 25%.

4

An optimal design of non-causal recursive digital filters with zero phase shift using Chebyshev approximation and linear programming

Mouffak Adnane

Przegląd Elektrotechniczny

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2021

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R. 97, nr 9

100--105

EN

This paper presents an optimal design for the special class of Non-Causal Recursive (NR) digital filters with zero phase shift. The design is based on the Chebyshev approximation problem. It can be transformed to an equivalent linear program under linear constraints of the zero phase. The given design yields more interesting pole-zero patterns that are not necessarily restricted to the classical design of Kormylo and Jain. The proposed optimal design allows an accurate zero phase shift and better magnitude characteristics in passband and stopband.

PL

W artykule przedstawiono optymalną procedurę projektowania dla specjalnej klasy nieprzyczynowych filtrów rekurencyjnych (NR) z zerowym przesunięciem fazowym. Projekt opiera się na problemie aproksymacji Czebyszewa. Można go przekształcić do równoważnego programu liniowego przy ograniczeniach liniowych fazy zerowej. Projekt daje bardziej interesujące wzory bieguna zerowego, które niekoniecznie ograniczają się do klasycznego projektu Kormylo i Jaina. Zaproponowana optymalna procedura umożliwia dokładne zerowe przesunięcie fazowe i lepszą charakterystykę amplitudy w paśmie przepuszczania i zatrzymywania.

5

Comparative Study of AMPL, Pyomo and JuMP Optimization Modeling Languages on a Network Linear Programming Problem Example

Karbowski Andrzej, Wyskiel Krzysztof

Pomiary Automatyka Robotyka

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2021

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R. 25, nr 3

23--30

EN

The purpose of this work is a comparative study of three languages (environments) of optimization modeling: AMPL, Pyomo and JuMP. The comparison will be based on three implementations of the shortest path problem formulated as a linear programming problem. The codes for individual models and differences between them will be presented and discussed. Various aspects will be taken into account, such as: simplicity and intuitiveness of implementation, availability of specific data structures for a LP network problems, etc.

PL

Celem pracy jest zbadanie i porównanie możliwości trzech języków (środowisk) modelowania optymalizacyjnego: AMPL, Pyomo i JuMP. Porównanie zostanie oparte na trzech implementacjach zadania najkrótszej ścieżki sformułowanego jako zadanie programowania liniowego. Przedstawione i omówione zostaną kody poszczególnych modeli oraz różnice między nimi. Pod uwagę będą brane różne aspekty, takie jak: prostota i intuicyjność implementacji, dostępność określonych struktur danych dla problemów z siecią LP itp.

6

An example to illustrate several aspects of optimization theory in Managerial Economics

Lahiri Somdeb

Managerial Economics

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2021

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Vol. 22, no. 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

Cost optimization and risk minimization during teamwork organization

Krynke Marek, Mielczarek Krzysztof, Kiriliuk Olga

Management Systems in Production Engineering

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2021

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nr 2 (29)

145--150

EN

In the paper the problem of personnel allocation under threat was presented. The possibilities of undertaking optimization measures in the process of workers’ health and safety and expenses incurred were emphasized. A mathematical model for this issue has been formulated. An algorithm solving the problem of staff allocation was presented. The evaluation criterion for this assignment was the minimization of worker safety risks. Simultaneous optimization of expenses incurred in the implementation of production tasks was taken into account. The productivity of the staff and all existing jobs with the skills of the employees also was considered. This problem was solved using GNU Octave. The example presented in the paper shows that in case of the most unfavorable allocation of tasks to employees, it will lead to a significant reduction in profits and may increase the risk of undesirable situations. The proposed analysis is the starting point for determining the risk in case of multi-position work.

8

Optimum transportation of relief materials aftermath the disaster

Nautiyal A., Kumar A., Poddar A., Parajuli N.

Journal of Achievements in Materials and Manufacturing Engineering

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2021

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Vol. 109, nr 1

26--41

EN

Purpose: Natural disasters disrupt not only the lives of individuals but also the functioning of society. Given the unpredictability of disasters and the uncertainty associated with them, preparation is the best way to mitigate and reduce the effects of the disaster. Design/methodology/approach: The study presents a mathematical model in the form of a multi-objective linear programming problem for the relief distribution from the airports which minimizes the total operational cost as well as travel time. Further, the solution approach and analytical results have also been discussed. Findings: The main aims at the preparedness stage are to identify and build infrastructures that might function as useful operation centres during a disaster. The study also provides decisions that include the type and number of vehicles for each affected location. Research limitations/implications: Airports can function as centres for relief collection and distribution. However, relief operations carried out through airports are often subject to problems such as stockpiling. Further, various modes are available for the transport of relief supplies- air, water, and land transport modes primarily. While aircraft and helicopters are faster, their costs of operation are too high. Instead, trucks are economical but very slow as compared to aircraft. Practical implications: The choice of model depends on many factors including the availability of vehicles, availability of routes, and criticality of situations. The choices made in turn affect the costs and the time of operations. Originality/value: The model converts a disaster scenario into a demand-supply problem with the aim being to decide allocations at specified intervals of time.

9

Conditions and a computation method of the constrained regulation problem for a class of fractional-order nonlinear continuous-time systems

Si Xindong, Yang Hongli, Ivanov Ivan G.

International Journal of Applied Mathematics and Computer Science

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2021

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Vol. 31, no. 1

17--28

EN

The constrained regulation problem (CRP) for fractional-order nonlinear continuous-time systems is investigated. New existence conditions of a linear feedback control law for a class of fractional-order nonlinear continuous-time systems under constraints are proposed. A computation method for solving the CRP for fractional-order nonlinear systems is also presented. Using the comparison principle and positively invariant set theory, conditions guaranteeing positive invariance of a polyhedron for fractional-order nonlinear systems are established. A linear feedback controller model and the corresponding algorithm of the CRP for fractional nonlinear systems are also proposed by using the obtained conditions. The presented model of the CRP is formulated as a linear programming problem, which can be easily implemented from a computational point of view. Numerical examples illustrate the proposed method.

10

A locally polynomial method for solving a system of linear inequalities

Evtushenko Yuri, Szkatuła Krzysztof, Tretyakov Alexey

Control and Cybernetics

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2021

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Vol. 50, No. 2

301--314

EN

The paper proposes a method for solving systems of linear inequalities. This method determines in a finite number of iterations whether the given system of linear ineqalities has a solution. If it does, the solution for the given system of linear inequalities is provided. The computational complexity of the proposed method is locally polynomial.

11

On transformation of conditional, conformant and parallel planning to linear programming

Galuszka Adam, Probierz Eryka

Archives of Control Sciences

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2021

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Vol. 31, No. 2

375--399

EN

Classical planning in Artificial Intelligence is a computationally expensive problem of finding a sequence of actions that transforms a given initial state of the problem to a desired goal situation. Lack of information about the initial state leads to conditional and conformant planning that is more difficult than classical one. A parallel plan is the plan in which some actions can be executed in parallel, usually leading to decrease of the plan execution time but increase of the difficulty of finding the plan. This paper is focused on three planning problems which are computationally difficult: conditional, conformant and parallel conformant. To avoid these difficulties a set of transformations to Linear Programming Problem (LPP), illustrated by examples, is proposed. The results show that solving LPP corresponding to the planning problem can be computationally easier than solving the planning problem by exploring the problem state space. The cost is that not always the LPP solution can be interpreted directly as a plan.

12

Discovering Communities in Networks: A Linear Programming Approach Using Max-Min Modularity

Ferdowsi Arman, Khanteymoori Alireza

Annals of Computer Science and Information Systems

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2021

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Vol. 25

329–-335

EN

Community detection is a fundamental challenge in network science and graph theory that aims to reveal nodes' structures. ‎While most methods consider Modularity as a community quality measure‎, ‎Max-Min Modularity improves the accuracy of the measure by penalizing the Modularity quantity when unrelated nodes are in the same community‎. ‎In this paper‎, ‎we propose a community detection approach based on linear programming using Max-Min Modularity‎. ‎The experimental results show that our algorithm has a better performance than the previously known algorithms on some well-known instances‎.

13

Risk management in the process of personnel allocation to jobs

Krynke Marek

System Safety : Human - Technical Facility - Environment

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2020

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Vol. 2, nr 1

82--99

EN

The strategy should be designed in such a way as the risk management can operate not only as a system for avoiding losses, but also risk management should allow recognizing and making use of occasions and create new opportunities for the organization. Risk management includes both an evaluation (analytical and evaluation) undertaking as well as planning and control activities aimed at minimizing (reducing) risk or maintaining it at an acceptable level. Security management can in particular be reduced to the issue of risk management, because risk is a quantitative expression of the functioning of systems in an environment where there are active sources of threats to system security. The article presents the problem of personnel allocation in hazardous conditions, emphasizing the possibilities of undertaking optimization actions in the safety management process. A mathematical model was formulated for this issue. An algorithm solving the problem of personnel allocation is presented. The proposed analysis is the starting point for determining the risk when using multi-station work.

14

Managing the effectiveness of machines during the assignment of tasks to the production

Krynke Marek

Quality Production Improvement - QPI

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2020

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Vol. 2, Iss. 1

188--196

EN

The allocation of production tasks to specific production resources is an important part of preparing the manufacturing process. The amount of profit and costs incurred depends on this division. The efficiency of production resources depends not only on the technologies used, but also on the tasks that will be carried out on them. Therefore, the management of machine efficiency includes both an evaluation (analytical and assessment undertaking, e.g. OEE) and planning activities aimed at maximizing the efficiency of machines by appropriately assigning production tasks to them. The article presents the problem of the allocation of production of various products to various production resources, including the efficiency of the use of machines and devices, emphasizing the possibilities of undertaking optimization actions in the cost management process. A mathematical model was formulated for this issue. An algorithm solving the problem of allocation of production tasks is presented. The solution was obtained using the Octave computing environment.

15

On the binary classification problem in discriminant analysis using linear programming methods

Olusola Michael O., Onyeagu Sydney I.

Operations Research and Decisions

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2020

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Vol. 30, No. 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.

16

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.

17

A linear programming methodology for approximate dynamic programming

Díaz Henry, Sala Antonio, Armesto Leopoldo

International Journal of Applied Mathematics and Computer Science

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2020

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Vol. 30, no. 2

363--375

EN

The linear programming (LP) approach to solve the Bellman equation in dynamic programming is a well-known option for finite state and input spaces to obtain an exact solution. However, with function approximation or continuous state spaces, refinements are necessary. This paper presents a methodology to make approximate dynamic programming via LP work in practical control applications with continuous state and input spaces. There are some guidelines on data and regressor choices needed to obtain meaningful and well-conditioned value function estimates. The work discusses the introduction of terminal ingredients and computation of lower and upper bounds of the value function. An experimental inverted-pendulum application will be used to illustrate the proposal and carry out a suitable comparative analysis with alternative options in the literature.

18

Numerical checking method for positive invariance of polyhedral sets for linear dynamical systems

Yang H., Hu Y.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2020

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Vol. 68, nr 3

593--599

EN

Positively invariant sets play an important role in the theory and applications of dynamical systems. The stability in Lyapunov sense of equilibrium x = 0 is equivalent to the existence of the ellipsoidal positively invariant sets. The constraints on the state and control vectors of dynamical systems can be formulated as polyhedral positively invariant sets in practical engineering problems. Numerical checking method of positive invariance of polyhedral sets is addressed in this paper. The validation of the positively invariant sets can be done by solving LPs which can be easily implemented numerically. The effectiveness of the proposed checking method is illustrated by examples. Compared with the now existing algebraic methods, numerical checking method is attractive and, importantly, easy to be implemented.

19

An output sensitivity problem for a class of linear distributed systems with uncertain initial state

Larrache Abdelilah, Lhous Mustapha, Rhila Soukina Ben, Rachik Mostafa, Tridane Abdessamad

Archives of Control Sciences

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2020

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Vol. 30, No. 1

139--155

EN

In this paper,we consider an infinite dimensional linear systems. It is assumed that the initial state of system is not known throughout all the domain Ω C Rn, the initial state x0 ϵ L2(Ω) is supposed known on one part of the domain Ω and uncertain on the rest. That means Ω = ω1 U ω2 U... U ωt with ωi ∩ ωj = ∅, ∀i ≠ j ϵ {1,...,t}, i ≠ j where ωi ≠ ∅ and x0(θ) = αi for θ ϵ ωi, ∀i, i.e., x0(θ) = [wzór] (θ) where the values α1,...,αr are supposed known and αr+1,...,αt unknown and 1ωi is the indicator function. The uncertain part (α1,...,(α)rof the initial state x0 is said to be (ɛ1,...,ɛr )-admissible if the sensitivity of corresponding output signal (yi)i≥0 relatively to uncertainties (αk)1≤k≤r is less to the treshold ɛk, i.e., ∥∂yi)/(∂αk∥ ≤ ɛk, ∀i≥ 0, ∀k ϵ {1,...,r]. The main goal of this paper is to determine the set of all possible gain operators that makes the system insensitive to all uncertainties. The characterization of this set is investigated and an algorithmic determination of each gain operators is presented. Some examples are given.

20

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.