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EN
The paper presents a production scheduling problem in a foundry equipped with two furnaces and one casting line, where the line is a bottleneck and furnaces, of the same capacity, work in parallel. The amount of produced castings may not exceed the capacity of the line and the furnaces, and their loads determine metal type from which the products are manufactured on the casting line. The purpose of planning is to create the processing order of metal production to prevent delays in the delivery of the ordered products to the customers. The problem is a mix of a lot-sizing and scheduling problems on two machines (the furnaces) run in parallel. The article gives a mathematical model that defines the optimization problem, and its relaxed version based on the concept of a rolling-horizon planning. The proposed approaches, i.e. commercial solver and Iterated Local Search (ILS) heuristic, were tested on a sample data and different problem sizes. The tests have shown that rolling horizon approach gives the best results for most problems, however, developed ILS algorithm gives better results for the largest problem instances with tight furnace capacity.
EN
The cooperation of wind farms with the power system requires that they meet the requirements related to reactive power management. In practice, it concerns both generation and production of this power in accordance with the requirements of network operators and EU Regulation 2016/631. The regulatory capacity of wind turbine generators is not sufficient to meet these requirements, in particular for farms connected to the power system via a 110 kV cable line with a length of several dozen kilometers. It is required to use various additional devices – fixed or variable shunt reactor, capacitor batteries, static VAR compensators (SVC). In the article, a compensation quality indicator was defined, by means of which it is possible to assess and select the optimal set of devices supporting the farm’s generation and reactive power consumption capabilities. Due to the application of multicriteria optimization, this indicator unifies both the technical effectiveness of individual systems and the economies of their use.
3
EN
This paper explores selected heuristics methods, namely CDS, Palmer’s slope index, Gupta’s algorithm, and concurrent heuristic algorithm for minimizing the makespan in permutation flow shop scheduling problem. Its main scope is to explore how different instances sizes impact on performance variability. The computational experiment includes 12 of available benchmark data sets of 10 problems proposed by Taillard. The results are computed and presented in the form of relative percentage deviation, while outputs of the NEH algorithm were used as reference solutions for comparison purposes. Finally, pertinent findings are commented.
4
Content available remote Forecasting and predicting in engineering tasks
EN
The work analyzes the tasks of solving problems, which consist in determining the events that may occur through some time after the completion of the process of solving the problem. One of the possible classifications of such tasks is proposed. The analysis of differences between different types of tasks is carried out, features of implementing the processes of their resolution are revealed. The paper considers in detail such types of tasks as prognosis and prediction. Differences are described between these processes with each other and the characteristics that determine each of the processes. The comparison of various types of processes in the overall forecasting process is presented.
PL
Tematem publikacji jest rozwiązywanie problemów polegających na określaniu zdarzeń, które mogą mieć miejsce po zakończeniu procesu rozwiązywania problemu. W artykule zaproponowano jedną z możliwych klasyfikacji takich zadań. Ponadto, przeprowadzono analizę różnic rozmaitych zadań. Przedstawiono także cechy wdrażania procesów ich rozwiązywania. W artykule szczegółowo rozważano takie rodzaje zadań, jak prognozowanie i przewidywanie. Opisano różnice między tymi procesami oraz cechy charakterystyczne, które określają każdy z wymienionych procesów. Przedstawiono porównanie różnych rodzajów procesów w całościowym procesie prognozowania.
PL
W artykule opisany jest rzeczywisty problem przydziału pracowników do stanowisk pracy występujący w jednostkach administracji celnej. Zakłada się, że alokacja pracowników do stanowisk powinna być losowa, niemożliwa do przewidzenia dla pracowników. W poszukiwanej alokacji zalecane jest również unikanie przydziału pracowników do stanowisk, na których w ostatnim czasie pracowali najczęściej. Proponowany jest model matematyczny przydziału pracowników do stanowisk, który bierze pod uwagę rotację stanowisk. Dla tego modelu opracowany jest algorytm heurystyczny, który tworzy losową alokację pracowników.
EN
The article describes the real problem of assignment of workers to workplaces occurring in customs administrations. This problem assumes that the allocation of employees to stations should be random, unpredictable for workers. It is also advisable to avoid assigning staff to workplaces where they have worked most recently. A mathematical model of the allocation of staff is proposed to the position, which takes into account the job rotation. For this model a heuristic algorithm, which creates random allocation of employees, is developed.
EN
The problem of sequencing jobs on a single machine to minimize total cost (earliness and tardiness) is nowadays not just important due to traditional concerns but also due to its importance in the context of Collaborative Networked Organizations and Virtual Enterprises, where precision about promptly responses to customers’ requests, along with other important requirements, assume a crucial role. In order to provide a contribution in this direction, in this paper the authors contribute with an applied constructive heuristics that tries to find appropriate solutions for single machine scheduling problems under different processing times and due dates, and without preemption allowed. In this paper, two different approaches for single-machine scheduling problems, based on external and internal performance measures are applied to the problem and a comparative analysis is performed. Computational results are presented for the problem under Just-in-Time and agile conditions on which each job has a due date, and the objective is to minimize the sum of holding costs for jobs completed before their due date and tardiness costs for jobs completed after their due date. Additional computational tests were developed based on different customer and enterprise oriented performance criteria, although preference is given to customer-oriented measures, namely the total number of tardy jobs and the maximum tardiness.
PL
W pracy omówiono heurystyczne metody rozwiązania problemu komiwojażera za pomocą algorytmów sztucznej inteligencji. Oprócz niemal klasycznych algorytmów opartych na sztucznych sieciach neuronowych i algorytmach genetycznych (ewolucyjnych) zostały przeanalizowane nowoczesne algorytmy korzystające z tzw. inteligencji roju (stada). W tej grupie zostały przeanalizowane algorytmy kolonii pszczół i stada ptaków. Szerzej zostały przedyskutowane algorytmy mrówkowe, bardzo ściśle związane z suboptymalizacją tras komunikacyjnych.
EN
The paper discusses the heuristic methods of solving the traveling salesman problem using artificial intelligence algorithms. In addition to almost classic algorithms based on artificial neural networks and genetic (evolutionary) algorithms, modern algorithms using the so-called swarm intelligence (herd). In this group, the algorithms for colonies of bees and flocks of birds have been analyzed. The formic algorithms, very closely related to the suboptimization of communication routes, have been discussed in more detail.
8
Content available Fast truck-packing of 3D boxes
EN
We present formulation and heuristic solution of a container packing problem observed in a household equipment factory’s sales and logistics department. The main feature of the presented MIP model is combining several types of constraints following from the considered application field. The developed best-fit heuristic is tested on the basis of a computational experiment. The obtained results show that the heuristic is capable of constructing good solutions in a very short time. Moreover, the approach allows easy adjustment to additional loading constraints.
EN
There is high demand for storage related services supporting scientists in their research activities. Those services are expected to provide not only capacity but also features allowing for more exible and cost ecient usage. Such features include easy multiplatform data access, long term data retention, support for performance and cost dierentiating of SLA restricted data access. The paper presents a policy-based SLA storage management model for distributed data storage services. The model allows for automated management of distributed data aimed at QoS provisioning with no strict resource reservation. The problem of providing users with the required QoS requirements is complex, and therefore the model implements heuristic approach for solving it. The corresponding system architecture, metrics and methods for SLA focused storage management are developed and tested in a real, nationwide environment. Keywords distributed storage systems, quality of service, service level agreement, management model, heuristics.
PL
Praca poświęcona jest problemowi znajdowania najkrótszej drogi w grafie poszukiwań. Zastosowano do tego celu algorytmy mrówkowe. Zbudowano model optymalizacyjny. Wybrano 8 różnych algorytmów mrówkowych. Przedstawiono i omówiono uzyskane wyniki optymalizacji długości drogi.
EN
The presented research results indicate the usefulness of ant algorithms in the optimization of the road length. Admittedly, ant algorithms do not guarantee an optimal solution, but they provide a suboptimal (rational) solution. In a situation where we have limited time to solve the optimization problem, the guarantee of terminating the algorithm and obtaining a rational, acceptable solution is an attractive alternative for conducting long-term calculations and finding a little better solution.
PL
W artykule postawiona zostaje teza, że polityka gospodarcza, wbrew popularnym opiniom nie może opierać się na wiedzy naukowej. Teza zostaje poparta szeregiem argumentów wskazujących problematyczność stosowania twierdzeń naukowych w praktycznym działaniu. Nie oznacza to jednak, że decydent skazany jest na działanie nieracjonalne. W tym kontekście wykazane zostaje, że właściwym narzędziem umożliwiającym podejmowanie lepszych decyzji jest strategia. Strategia pojmowana jako pewien system reguł decyzyjnych a nie jako plan działania. Egzemplifikacją tego rozumowania staje się zaprezentowanie zasady ostrożności, która jest jedną z najbardziej fundamentalnych i uniwersalnych reguł decyzyjnych, na których może opierać się polityka gospodarcza państwa.
EN
The article puts forward a hypothesis according to which economic policy, contrary to popular opinion, cannot be based on scientific knowledge. This thesis is supported by a series of arguments indicating how problematic is to apply scientific theories in practical action. Especially in the field of economic policy. This doesn’t mean however, that a decision maker must be irrational. In this context, it is demonstrated, that strategy is a right tool to make better decisions. A strategy, understood as a system of decision rules, not as an action plan. This reasoning is being exemplified by the introduction of precaussionary principle, which is one of the most fundamental and universal decision rules on which economic policy of the state can be based.
12
EN
Automatic Identification System (AIS) is primarily used as a tracking system for ships, but with the launch of satellites to collect these data, new and previously untested possibilities are emerging. This paper presents the development of heuristics for establishing the specific ship type using information retrieved from AIS data alone. These heuristics expand the possibilities of AIS data, as the specific ship type is vital for several transportation research cases, such as emission analyses of ship traffic and studies on slow steaming. The presented method for developing heuristics can be used for a wider range of vessels. These heuristics may form the basis of large-scale studies on ship traffic using AIS data when it is not feasible or desirable to use commercial ship data registers.
EN
The article seeks to clarify some concepts and principles that are used in constructing algorithms that utilize particle swarm as a tool for searching extremes of target functions, including heuristic algorithms. The author also draws attention to some philosophical aspects of creating metaphors by ordering basic ways of constructing the transition vectors.
EN
Scheduling is one of the most important decisions in production control. An approach is proposed for supporting users to solve scheduling problems, by choosing the combination of physical manufacturing system configuration and the material handling system settings. The approach considers two alternative manufacturing scheduling configurations in a two stage product oriented manufacturing system, exploring the hybrid flow shop (HFS) and the parallel flow shop (PFS) environments. For illustrating the application of the proposed approach an industrial case from the automotive components industry is studied. The main aim of this research to compare results of study of production scheduling in the hybrid and the parallel flow, taking into account the makespan minimization criterion. Thus the HFS and the PFS performance is compared and analyzed, mainly in terms of the makespan, as the transportation times vary. The study shows that the performance HFS is clearly better when the work stations’ processing times are unbalanced, either in nature or as a consequence of the addition of transport times just to one of the work station processing time but loses advantage, becoming worse than the performance of the PFS configuration when the work stations’ processing times are balanced, either in nature or as a consequence of the addition of transport times added on the work stations’ processing times. This means that physical layout configurations along with the way transport time are including the work stations’ processing times should be carefully taken into consideration due to its influence on the performance reached by both HFS and PFS configurations.
PL
Artykuł poświęcony jest metodą heurystycznym w zadaniu optymalizacji procesów magazynowych. Ze względu na dużą złożoność procesów zachodzących w magazynie aby dobrze opisać i oszacować te procesy tradycyjne metody analizy danych nie spełniają swojego zastosowania. W celu agregacji reguł postępowania i znalezienie jak najlepszych czyli optymalnych procesów magazynowych autor zaproponował metodę heurystyczną. W tym celu zostały przedstawione kolejne etapy tworzenia modelu w programie AnyLogic. Pozwala to na budowę modelu magazynu oraz poprzez parametryzowanie jego czynników szukanie najlepszych rozwiązań. Metoda oparta na heurystykach mająca zastosowanie w programie AnyLogic pozwala na tworzeni optymalnych rozwiązań oraz wskazuje na wąskie gardła jakie mogą pojawić się przy równych obciążeniach systemu.
EN
The article is devoted to the heuristic method in the task of optimizing warehouse processes. Due to the high complexity of the processes in the warehouse, in order to describe and evaluate these processes well, traditional data analysis methods do not meet their application. In order to aggregate the rules of conduct and find the best or optimal warehouse processes, the author proposed a heuristic method. For this purpose, the next steps in creating a model in AnyLogic were presented. This allows you to build a warehouse model and by parameterizing its factors to find the best solution. AnyLogic's heuristic-based heuristics method makes it possible to create optimal solutions and pinpoint the bottlenecks that can occur with equal load on the system.
EN
In the paper, we present a coordinated production planning and scheduling problem for three major shops in a typical alloy casting foundry, i.e. a melting shop, molding shop with automatic line and a core shop. The castings, prepared from different metal, have different weight and different number of cores. Although core preparation does not required as strict coordination with molding plan as metal preparation in furnaces, some cores may have limited shelf life, depending on the material used, or at least it is usually not the best organizational practice to prepare them long in advance. Core shop have limited capacity, so the cores for castings that require multiple cores should be prepared earlier. We present a mixed integer programming model for the coordinated production planning and scheduling problem of the shops. Then we propose a simple Lagrangian relaxation heuristic and evolutionary based heuristic to solve the coordinated problem. The applicability of the proposed solution in industrial practice is verified on large instances of the problem with the data simulating actual production parameters in one of the medium size foundry.
EN
The need for flexibility of layout planning puts higher requirements for uti-lisation of layout and location problem solving methods. Classical methods, like linear programming, dynamic programming or conventional heuristics are being replaced by advanced evolutionary algorithms, which give better solutions to large-scale problems. One of these methods are also genetic algorithms. This article describes the genetic algorithm utilisation in the production layout planningunder the terms of the digital factory concept.
EN
This paper describes research related to the use of heuristics in diagnostic tasks of complex technical objects. To build heuristics, the use of text models for technical objects is proposed. Therefore, this paper examines output methods of heuristics from text models and their transformation into logical formulae suitable for use in diagnostic algorithms. Analysis has been carried out for tasks solved during diagnostics, and methods of using heuristics in certain tasks have been reviewed. It is proposed to use heuristics for decision making while implementing certain algorithm steps of monitoring tasks for diagnostic parameters that are solved during diagnostics.
EN
The dynamic development of information technologies has significantly improved the process of planning and controlling the operation of electrical power systems, nevertheless, we are still looking for methods and solutions which will allow to optimize EPS. The article describes heuristic methods which can be used in electrical power engineering and which will be used to solve OPF (Optimal Power Flow) problems.
EN
The Internet shopping optimization problem arises when a customer aims to purchase a list of goods from a set of web-stores with a minimum total cost. This problem is NP-hard in the strong sense. We are interested in solving the Internet shopping optimization problem with additional delivery costs associated to the web-stores where the goods are bought. It is of interest to extend the model including price discounts of goods. The aim of this paper is to present a set of optimization algorithms to solve the problem. Our purpose is to find a compromise solution between computational time and results close to the optimum value. The performance of the set of algorithms is evaluated through simulations using real world data collected from 32 web-stores. The quality of the results provided by the set of algorithms is compared to the optimal solutions for small-size instances of the problem. The optimization algorithms are also evaluated regarding scalability when the size of the instances increases. The set of results revealed that the algorithms are able to compute good quality solutions close to the optimum in a reasonable time with very good scalability demonstrating their practicability.
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