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EN
This article deals with an optimisation procedure of inner geometry of rolling elements designed for spherical roller bearings. A process of selection of the most appropriate solution to increase spherical roller bearing durability is understood under the term optimisation in this case. The aim of this article is to examine the impact of a change of inner geometry on the durability and reliability of spherical roller bearings regarding production technology and competitiveness. Contact strain along with a spherical roller by means of Finite Element Method (FEM) in contact points of components of a spherical roller bearing by means of designed 3D parametric models. The most appropriate shape of inner geometry of a bearing from the standpoint of calculated durability will be determined based on the results of analyses.
EN
Purpose: This article aims to present the theoretical solution to the problem of waste management. Design/methodology/approach: This model is a proposal for the assessment of bids, which enables the unification of assessments against the criteria expressed in various measures, includes determining the importance of individual criteria, and thus the simulation of assessments when changing the criteria weight values. Findings: The article presents the theoretical optimization model of waste collection and management, which may be helpful in solving the problem of waste more effectively. Research limitations/implications: The article is limited to presenting only the basic model of waste management optimization. Due to the fact that in individual administrative units of the country solving the problem of waste is a local issue, it was impossible to present a solution that would be adequate for each region of the country. Practical implications: The article presents a theoretical model that can form the basis of a practical optimal solution to the problem of waste in individual administrative units of the country. Social implications: Optimal waste management is an extremely important social issue. In addition to efficient waste management, increasing public awareness of the impact of precipitation segregation and recycling on the environment is an extremely important issue. Originality/value The presented model is a flexible model that can be used by individual administrative units, taking into account the specificities of waste management possibilities and restrictions in a given region.
EN
The subject of this paper is the inventory-production problem, which is a one of the optimization problems in a decision area in which inventory volume and production volume are considered together. There are many approaches to this problem but for the first time, this problem is modelled by means of a capacitated graph network and a solution to the problem is proposed on the basis of this model which consists of finding the maximum flow with the minimum sum of production and inventory cost. In this article, only a solution for one kind of product for the deterministic inventory-production optimisation problem is presented and for this one kind of product, a maximum flow with a minimum cost for each considered demand period is calculated. The maximum flow with minimum cost is a solution to the homogenous inventory-production optimisation problem. The solution to the one kind of product for the inventoryproduction problem consist of maximum flow with minimum cost for a total demand from all periods, which has been taken into consideration.
EN
The paper presents a mathematical model of a positional game of the safe control of a vessel in collision situations at sea, containing a description of control, state variables and state constraints as well as sets of acceptable ship strategies, as a multi-criteria optimisation task. The three possible tasks of multi-criteria optimisation were formulated in the form of non-cooperative and cooperative multi-stage positional games as well as optimal non-game controls. The multicriteria control algorithms corresponding to these tasks were subjected to computer simulation in Matlab/Simulink software based on the example of the real navigational situation of the passing of one’s own vessel with eighteen objects encountered in the North Sea.
PL
Aby umożliwić w praktyce optymalizację procesu realizacji inwestycji drogowych, Ministerstwo Infrastruktury zleciło opracowanie Katalogu typowych drogowych obiektów mostowych oraz towarzyszącego mu Podręcznika projektowania drogowych obiektów mostowych według Eurokodów w praktyce.
EN
In order to enable the optimisation of the road investment completion process in practice, the Ministry of Infrastructure has commissioned the development of the Catalogue of typical road bridge structures and the associated Manual of designing road bridge structures according to Eurocodes in practice.
EN
The article discusses the problem of choosing the optimal frequency of functional tests, taking into account the reliability and law requirements, but also the impact of business aspects in the company. The subject of functional test interval is well described for purposes of the process industry. Unfortunately, this is not the case for the machinery safety functions with low demand mode. This is followed by a presentation of the current business approach, which, in order to achieve industrial excellence, monitor their performance through the appropriate selection of key performance indicators. In addition, companies are increasingly exploring potential risks in the following areas: new challenges in advanced risk management, including the perception of the company’s facilities as a safe workplace insight of customers and business partners. Eliminating potential hazards is increasingly taking into account, especially the impact of human activity and its interaction with machines. The case study has been presented based on the machines used for the production of tire semi-finished products. In this article, the authors propose a solution for selecting the interval of functional tests of safety functions and additional machine protection measures as a compromise to achieve satisfactory results in terms of safety requirements, performance and legal requirements.
EN
Purpose: The aim of the work is to build physically sound engineering and design schemes that take into account the behaviour of polycrystalline metal systems under intense loads and allow optimization of surface treatment technologies to increase the operational reliability parameters of products. Design/methodology/approach: Using the approaches of thermodynamics, a methodological scheme is proposed, on the basis of which it is possible to optimize surface engineering technologies to increase the contact durability of details. Findings: It was found that the maximum increase in the durability of steel 40X13 (AISI 420) is achieved with thermocyclic ion nitriding in a cycle of ± 50°C, and the minimum with isothermal nitriding. Research limitations/implications: In this paper, the optimization of technological solutions to increase the contact durability of structural elements operating under prevailing power loads is given. Practical implications: Using the proposed mathematical relationships, optimal technological regimes of ion-plasma nitriding were established for various operating conditions, under which the maximum durability and wear resistance of 40X13 (AISI 420) steel are ensured. Originality/value: The paper proposes an approach to the formation of functionally gradient surface layers of steel with specified operational parameters when choosing optimal nitriding technology modes based on nonlocal mathematical models.
EN
The Bluetooth Low Energy (BLE) MESH network technology gains popularity in low duty IoT systems. Its advantage is a low energy consumption that enables long lifetime of IoT systems. The paper proposes and evaluates new MRT management methods, i.e. exact and heuristic, that improves energy efficiency of BLEMESH network by minimizing the number of active relay nodes. The performed experiments confirm efficiency of the MRT methods resulting in significantly lower energy consumption of BLE MESH network.
EN
The performance of some map applications can be improved not only through the compression of raster files or appropriate data server configuration, but also by using source file minification. Minification can be more or less effective. The objective of the paper is to perform a comparative analysis of selected online tools for minifying JavaScript code and to measure the impact of such minification on the performance of a map application. Minification and performance tests were conducted on a prototype map application. The application was developed as a ZoomLens component extending the functionality of any website. Various tools yielded similar results of the JavaScript file minification, and it did not affect the values of aggregate performance indices. In most cases, it reduced the JavaScript file size by over a half. It has been demonstrated that minification of JavaScript code alone may not be sufficient to improve the application performance noticeably.
EN
Industry, which on average accounts for about 60% of commodity exports in the EU-28, with over 58% resulting from the processing industry, plays a key role in ensuring the competitiveness of EU countries. The article aims to simulate the influence of structural processing industry parameters on the industry’s efficiency. Correlation methods and the regression analysis were used to substantiate the hypotheses regarding the effect that the share comprised of high-tech and medium-high-tech industries has on the output structure, and the impact made by the share of imports in the intermediate consumption of those industries on the efficiency (the share of gross value added (GVA) in output) of the processing industry. Based on the criteria indicating the increased technological level and reduced import dependence, economic and mathematical models of optimisation were created for the output structure and intermediate consumption of the processing industry, which were then solved using the linear programming method. The authors present the mathematical proof of the relationship between the change in structural parameters (shares of high-tech and medium-tech industries and the share of imports in the structure of their intermediate consumption) of the processing industry and the ratio of the gross value added/output. The results of the simulation, which were based on data from the European Statistical Office and the Organization for Economic Cooperation and Development, provide an analytical basis for selecting industrial policy benchmarks.
EN
This paper deals with genetic algorithms as an optimisation method and its use for optimisation of the machining process in the CAM system. Tool path verification and optimisation are two best ways of dramatically improving manufacturing operations while saving money with relatively little work. Genetic algorithms can be used for improvement of these operations and considerably reduce length of tool paths leading to the reduction of machine times and optimisation of cutting parameters. Provides the software application created to optimise processes of boring and local milling (Incomplete sentence; what or who provides).
EN
This article presents the results of a survey regarding architects’ expectations towards software for automated floor plan generation (AFPG) and optimisation processes in architectural design. More than 150 practising architects from Poland and abroad took part in the survey. Survey results were then extracted, ordered and interpreted with the use of data mining. The survey structure, methodology and analytical tools used are described in the paper.
EN
Some proposition of mathematical logic application for optimization of logistic nets describing motor transport has been presented in this paper. Some algorithm for optimization steps has been proposed in the article. In presented example has been elaborated some optimization of logistic net for motor transport. The optimized logistics network for motor transport significantly improves reliability and contributes to the economical use of the vehicle.
EN
Block caving is an underground mining technique which extracts ore from the base, rather than from the top, of typically massive deposits. Mining infrastructure is developed below the deposit before extraction commences. A network of tunnels provides access to a collection of drawpoints from which ore is mucked and hauled. With large deposits, not all drawpoints are developed simultaneously and the opening of drawpoints is sequenced to facilitate orderly extraction of ore columns above drawpoints. Sequencing fixes the initiation point for the entire block cave, or a part of it, as well as identifying the direction of cave advancement. The sequence of opening drawpoints influences the mine economics and is an integral aspect of planning a block cave mine. This paper discusses the optimisation of sequencing based on the net present value associated with extraction over the life-of-mine. It is shown that the maximum attainable net present value is obtained by a sequence in which ore columns are ranked in descending order of value. If significant variation of grade is present inside columns, an iterative procedure is given which corrects the sequence which yields the maximum net present value. The sequence with maximum net present value may not be practical or attractive from a caving perspective. Systematic design of sequences which permit orderly development of a block cave is discussed. To provide context, the net present value obtained from these feasible sequences is compared with the maximum attainable net present value. It is shown that the best feasible sequences in terms of net present value are preferentially initiated in zones with columns of high-grade ore.
EN
The article addressed the problem of the allocation of tasks in one of the warehouse processes (order picking). The objective was to obtain the optimum solution, which guarantees the minimum execution time of particular tasks by warehouse personnel. To optimise the issue mentioned above Excel spreadsheet with the Solver module was applied.
PL
W artykule poddany został analizie problem przydziału zadań w jednym z procesów magazynowych (kompletacji). Celem było uzyskanie rozwiązania optymalnego gwarantującego minimalny czas realizacji określonych zadań przez pracowników magazynowych. W celu optymalizacji ww. zagadnienia zastosowano arkusz kalkulacyjny Excel z wykorzystaniem dodatku Solver.
16
Content available Edge Weight Power and Frequency Assignment Algorithm
EN
In cellular networks, cells are grouped more densely around highly populated areas to provide more capacity. Antennas are pointed in accordance with local terrain and clutter to reduce signal shadows and interference. Hardware parameters are easily set during installation but difficult to change thereafter. In a dynamic environment of population migration, there is need to continuously tune network parameters to adapt the network performance. Modern mobile equipment logs network usage patterns and statistics over time. This information can be used to tune soft parameters of the network. These parameters may include frequency channel assignment or reuse, and transmitter radiation power assignment to provide more capacity on demand. The paper proposes that by combining the frequency and power assignments, further optimisation in resource allocation can be achieved over a traditional frequency assignment. The solution considers the interference, traffic intensity and use of priority flags to bias some edges. An Edge Weight Power and Frequency Assignment Algorithm is presented to solve the resource allocation problem in cellular networks. The paper also analyses the performance improvements obtained over that of the Edge Weight Frequency Assignment Algorithm. The results show that the proposed algorithm improves the performance of the Edge Weight Frequency Assignment Algorithm depending on the initial structure of the graph.
PL
Artykuł dotyczy optymalizacji eksploatacji gazowej sieci przesyłowej wysokiego ciśnienia. Analizowano algorytmy optymalizacji przyjmując różne postaci funkcji celu. Porównywano algorytm minimalizujący koszty eksploatacji tłoczni z algorytmem zapewniającym maksymalną masę gazu zgromadzoną w systemie oraz algorytm dwukryterialny którego funkcja celu uwzględnia zarówno koszty eksploatacji jak również koszty zwiększonego magazynowania gazu w rurach.
EN
The article concerns the optimization of the operation of the gas high-pressure transmission network. Optimization algorithms were analyzed assuming three different forms of the objective function. The algorithm minimizing the running costs of the compressor stations, the algorithm ensuring the maximum linepack of the system and the dual-objective function which takes into account the running costs and the costs of linepack maximisation in gas system have been compared.
EN
This paper presents a method of selection of an optimal (the best possible) thermochemical treatment of a steel guide of yarn for a ring spinning frame with the use of an optimisation procedure based on assumed criteria, and with consideration of their importance. Yarn guides for a ring spinning frame were manufactured from three brands of steel and were subjected to the following types of thermochemical treatment: 50SiCr4 steel (chrome hardening, diffusion boronising, and titanising); 41CrAlMo7 steel (nitrosulfiding and nitrogen case hardening), and C45 steel (diffusion boronizing). Unit manufacturing costs and six criteria of manufacturing quality: four parameters of surface texture (Rq, Rp, RΔq, rw), maximal hardness of the surface layer (HV0,1), and the case depth of the surface layer (gww), were taken as criteria for assessment. Values of the assessment criteria obtained from calculations and measurements were subjected to normalisation. The knowledge of experts and importance matrix B, evaluated with the use of the Saaty method (consisting in pairwise comparison of the successive criteria) were used to determine the importance of the criteria taken for the assessment. Using the Power method, eigenvalues of matrix B were found, as well as corresponding coordinates yt of the eigenvector, which are simultaneously the weights of the corresponding criteria. Normalised decisions were created in the next step by raising each component of the normalised assessments to a power equal to the corresponding weight. In the last step of the procedure, a single optimal lining-up was created comprising the smallest s-th components of the individual decisions d1, d2, ..., dm. The best variant of the thermochemical treatment was recognised as corresponding to the largest component of the optimal lining-up, which in our case is the diffusion boronizing. Key words: optimisation, thermochemical treatment, yarn guide.
PL
W pracy przedstawiono dobór optymalnej (najlepszej) obróbki cieplno-chemicznej stalowego prowadnika przędzy przędzarki obrączkowej z zastosowaniem metody postępowania optymalizacyjnego ze względu na przyjęte kryteria z uwzględnieniem ich ważności. Prowadniki przędzy przędzarki obrączkowej wykonano z trzech rodzajów stali i poddano następującym rodzajom obróbki cieplno-chemicznej: 50SiCr4 (chromowaniu, borowaniu i tytanowaniu dyfuzyjnemu), 41CrAlMo7 (azotonasiarczaniu i azotowaniu) oraz C45 (borowaniu dyfuzyjnemu). Jako kryteria oceny przyjęto jednostkowy koszt wytwarzania oraz sześć kryteriów jakości wytwórczej: cztery parametry struktury geometrycznej powierzchni (Rq, Rp, RΔq, rw) i maksymalną twardość na powierzchni HV0,1 oraz głębokość utwardzenia warstwy wierzchniej gww. Wartości kryteriów ocen uzyskane z obliczeń i pomiarów poddano normalizacji. Do określenia ważności przyjętych do oceny kryteriów wykorzystano wiedzę ekspertów oraz macierz ważności B wyznaczoną metodą Saaty’ego, polegającą na porównaniu kolejnych par kryteriów. Stosując metodę Powera znaleziono wartości własne macierzy B i odpowiadające im współrzędne yt wektora własnego, które są równocześnie wagami odpowiadających kryteriów. Następnie utworzono decyzje unormowane przez podniesienie każdego składnika ocen unormowanych do potęgi równej odpowiedniej wadze. W ostatnim etapie utworzono jedno uszeregowanie optymalne, którego składnikami są najmniejsze s-te składniki poszczególnych decyzji d1, d2, ..., dm. Wariantem najlepszym obróbki cieplno-chemicznej jest ten, któremu odpowiada największy składnik uszeregowania optymalnego, w naszym przypadku jest to borowanie dyfuzyjne.
PL
Energia promieniowana słonecznego (Słońce) docierająca do powierzchni Ziemi jest coraz częściej wykorzystywana jako alternatywne źródło energii elektrycznej. W artykule przedstawiono eksperymentalne badania optymalizacji sprawności trzech krystalicznych ogniw krzemowych o różnej zawartości fosforu w warunkach naturalnych i laboratoryjnych. Wykazano, że badane ogniwa posiadają zdolność konwersji energii świetlnej na energię elektryczną. Maksymalna wartość sprawności wynosi ~14% przy wartości górowania Słońca 39,45°. Parametr sprawności jest dobrym narzędziem do badania optymalizacji efektu fotowoltaicznego i jakości wykonanego ogniwa fotowoltaicznego.
EN
Energy of solar radiation reaching the Earth’s surface is increasingly used as an alternative source of electric energy. Presented are experimental investigations conducted in natural and laboratory conditions and concernig the efficiency optimisation of three cristalline silicon cells with different phosphorus content. It is proved that the investigated cells are able to convert light energy into the electric one. Maximum efficiency value is ~14% with the angular highest position of the Sun equal 39,45°. Efficiency parameter is a good tool to investigate the optimisation of the PV effect and the quality of the constructed PV cell.
EN
This paper presents results of evolutionary minimisation of peak-to-peak value of a?multi-tone signal. The signal is the sum of multiple tones (channels) with constant amplitudes and frequencies combined with variable phases. An exemplary application is emergency broadcasting using widely used analogue broadcasting techniques: citizens band (CB) or VHF FM commercial broadcasting. The work presented illustrates a?relatively simple problem, which, however, is characterised by large combinatorial complexity, so direct (exhaustive) search becomes completely impractical. The process of minimisation is based on genetic algorithm (GA), which proves its usability for given problem. The final result is a?significant reduction of peak-to-peak level of given multi-tone signal, demonstrated by three real-life examples.
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