Wyniki wyszukiwania - BazTech

1

Deployment of a predictive-like optimal control law on a servo drive system using linear programming approach

Horla Dariusz, Pinczewski Piotr

Archives of Electrical Engineering

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2023

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Vol. 72, nr 4

1005--1016

EN

Current drive control systems tend to push control loops to the limits of their performance. One of the ways of doing so is to use advanced optimization algorithms, usually related to model-based off-line calculations, such as genetic algorithms, the particle swarmoptimisation or the others. There is, however, a simpler way, namely to use predictive control formalism and by formulation of a simple linear programming problem which is easy to solve using powerful solvers, without excessive computational burden, what is a reliable solution, as whenever the optimization problem has a feasible solution, a global minimizer can be efficiently found. This approach has been deployed for a servo drive system operated by a real-time sampled-data controller, verified between model-in-the-loop and hardwarein- the-loop configurations, for a range of prediction horizons, as an attractive alternative to classical quadratic programming-related formulation of predictive control task.

2

Comparative analysis of static and dynamic facility layouts design using the modeling of plantain flour as case study

Adeyeri Michael Kanisuru, Ayodeji Sesan Peter

Production Engineering Archives

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2022

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Vol. 28, Iss. 1

12--20

EN

Profit optimization at the expense of minimal resource utilization for product development has been the major focus of prospective investors. In an attempt to realize this goal, the present research consideration is tailored towards investigating the effect of introducing dynamic facility layout design. Therefore, this research study uses an existing designed plantain flour processing plant that consists of a washing machine, grating machine, dryer, milling machine and sieving machine. Modeling techniques incorporated with software development were employed on the existing static plant layout to optimize production time and cost of each of the processing units along with the layout. Also, dynamic constraints were introduced into the layouts while mathematical models were formulated to visualize how the output and production process would be. With these models, software for the optimization of static and dynamic layouts was developed. The comparative study was carried out based on the processing time, the number of machines needed for each layout type, the cost of operation and machine procurement cost for both static and dynamic layouts. The constraints introduced ensured that the system improved within the cost limit based on the current market situation and prevented unnecessary enlargement in the plant facility size while minimizing material congestion in the system. The distinction between static and dynamic layout configurations was further established by comparing the results from the layout configurations for a set of throughput masses ranging from 50 kg to 250 kg. Results showed that the cost of operation drops drastically by 69.6 % under dynamic layout configuration.

3

Insects as Food – Opportunities and Constraints®

Nasir Syifa Qolbiyah, Świąder Katarzyna

Postępy Techniki Przetwórstwa Spożywczego

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2022

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nr 2

137--154

EN

The interest of the food and feed industry in animal protein alternatives is increasing worldwide. Among the most commonly used alternatives are plant proteins, but interest in insect proteins as well as the use of whole insects in food is still growing. The aim of this study was to analyze the possibilities of using edible insects in food as well as the limitations associated with their use in food products. The production process, safety issues, consumer opinion, popularity of insects in different corners of the world, nutritional value, as well as the sustainability of insect production as a protein source compared to conventional production are discussed. The opportunities as well as the limitations in the use of insects in food were highlighted. Many examples of the use of insects in equal food products were also given. Despite the emerging economic and environmental opportunities associated with the use of edible insects as a protein alternative in the future, there are still some limitations and restrictions on the industrialization of edible insects in food products, from the breeding, processing and promotion of edible insects to their acceptance among consumers.

PL

Zainteresowanie przemysłu spożywczego jak i paszowego alternatywami białka zwierzęcego jest coraz większe na świecie. Wśród najczęściej wykorzystywanych alternatyw są biała roślinne, niemniej jednak zainteresowanie białkiem owadzim jak również wykorzystaniem całych owadów w żywności nadal rośnie. Celem artykułu była analiza możliwości wykorzystania jadalnych owadów w żywności jak również ograniczeń związanych z ich użyciem w produktach spożywczych. Omówiono proces produkcji, kwestie dotyczące bezpieczeństwa, opinii konsumenckiej, popularności owadów w różnych zakątkach świata, wartości odżywczej, jak również zrównoważonej produkcji owadów jako źródła białka w porównaniu do produkcji konwencjonalnej. Zwrócono uwagę na możliwości jak i ograniczenia w zastosowaniu owadów w żywności. Podano również wiele przykładów wykorzystania owadów w różnych produktach spożywczych. Pomimo pojawiających się możliwości ekonomicznych i środowiskowych związanych z wykorzystaniem jadalnych owadów jako alternatywy dla białka w przyszłości, nadal istnieją pewne ograniczenia i restrykcje w uprzemysłowieniu jadalnych owadów w produktach spożywczych, od hodowli, przetwarzania i promowania jadalnych owadów po ich akceptację wśród konsumentów.

4

The characteristics of selected triaxiality measures of the stresses for a C(T) specimen dominated by the plane strain state

Graba M.

International Journal of Applied Mechanics and Engineering

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2020

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Vol. 25, no. 1

52--74

EN

The paper presents a comprehensive analysis of the stress field and selected triaxiality parameters near the crack tip for C(T) specimen dominated by the plane strain state using the finite element method. It includes some theoretical information about elastic-plastic fracture mechanics, the basics of the FEM modeling and presentation of the numerical results. The FEM analysis includes calculations with large strain assumptions. The influence of the external load and crack length is discussed. Additional elements of the paper are a qualitative assessment of the size of plastic zones and the crack tip opening displacement.

5

Methodology for bottleneck identification in a production system when implementing TOC

Urban Wieslaw, Rogowska Patrycja

Engineering Management in Production and Services

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2020

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Vol. 12, no. 2

74--82

EN

For TOC (Theory of Constraints) implementation in a production system, the determination of the system’s bottleneck is a crucial step. Effective bottleneck identification allows setting priorities for the improvement of a production system. The article deals with a significant problem for the manufacturing industry related to the location of a bottleneck. The article aims for a detailed analysis of methods for bottleneck identification based on a comprehensive literature review and the design of a generalised methodology for bottleneck identification in the production system. The article uses two research methods, first, the combination of a narrative and scoping literature review, and second, the logical design. Several methods for bottleneck identification are reviewed and compared, finding some being similar, and others giving new insights into the evaluated production system. A methodology for bottleneck identification is proposed. It contains several detailed methods arranged in coherent steps, which are suggested to be followed when aiming for the recognition of a production system’s bottleneck. The proposed methodology is expected to be helpful in the practical TOC implementation. The presented methodology for the identification of bottlenecks in a production system is a practical tool for managers and experts dealing with TOC. However, it is still a conceptual proposal that needs to be tested empirically. The proposed methodology for bottleneck identification is an original concept based on the current literature output. It contributes to the production management theory as a practical managerial tool.

6

Elaboration of an expert system for sizing, designing and verifying flexible pavements

Bouacha Nadjet, Belachia Mouloud

Civil and Environmental Engineering Reports

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2020

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Vol. 30, no. 3

94--121

EN

The use of expert systems in the world of civil engineering, and in particular for roads, has become a necessity for the reason of the particularity, complexity, and diversity of the influencing parameters at the level of the design calculation, the latter of which represents the major source of subsequent degradation. This system consists of proposing a tool for helping the user firstly to size the body of the roadway, with several analytical methods and models (Pre-project, Boussinesq, Westgaard, and Burmister), and secondly, to offer different design possibilities (thickness and type of the material) that make up the layers. Lastly, it is to calculate the stresses and strains in order to compare them with admissible limits. The management of a knowledge base of complex natures (words, sentences, numbers, symbols, tables, calculation methods, equations, conditions, etc.) requires an adequate methodology which goes beyond the simple use of the technology but enables you to imagine the process of regrouping this mass of complex data and classifying the data, which can then be integrated into a database or spreadsheets and external programs designed with code compatible with the expert system generator. Our contribution relates initially to the formulation, organization, and preparation of the algorithms, and then the starting of the programs in order to conceive fully executable programs, the latter of which we can call the expert system. The validation of such a system was made as the work progressed, changes were made in the formulation of the rules, and the order and orientation of the data in the knowledge that the advantage of this type of system is the possibility of permanently reinforcing the database with human expertise in the field, or in books, especially so that we can avoid data loss due to illnesses, retirement, etc.

7

Elimination of constraints in the production process of power equipment components and the analysis of the resulting benefits

Knop Krzysztof

Production Engineering Archives

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2019

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Vol. 24

37--42

EN

The article presents the results regarding the elimination of constraints in the production process of a power equipment subassembly, a boiler chamber, together with an analysis of the benefits resulting from this, both financial and non-financial. The significance of bottlenecks in the production process, ways of its identification and limitations - in general - are presented. The article is a case-study of an attempt to eliminate the bottleneck in the production process of the boiler chamber, which turned out to be the process of drilling and marking-off, and work stations representing these processes. In order to eliminate the limitation, it was decided to replace the existing tracing and drilling work with a numerically controlled device - a boring machine moved from the liquidated department.. As a result, labor-intensive, manual chambers marking-off and the process of drilling holes with a smaller diameter drill have been eliminated. A number of benefits has been demonstrated resulting from the elimination of the bottleneck in the process, first of all, it was possible to reduce the duration of the marking-off and drilling operations and reduce the costs of the boiler chamber production process.

8

The characterization of the stress fields near a crack tip for a compact specimen for elastic-plastic materials dominated by the plane strain state

Graba M.

International Journal of Applied Mechanics and Engineering

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2019

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Vol. 24, no. 3

549--576

EN

The paper presents a comprehensive analysis of the stress field near a crack tip for a compact specimen dominated by the plane strain state using the finite element method. The analysis also includes the calculation of some parameters of in-plane constraints, both for small and large strain assumptions. It discusses the influence of the material characteristic, relative crack length and external load for the stress field, and the in-plane constraint parameter. The approximation formulas for some in-plane constraint parameters are presented.

9

Condensers with infinitely many touching Borel plates and minimum energy problems

Zorii Natalia

Bulletin of the Polish Academy of Sciences. Mathematics

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2019

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Vol. 67, no. 2

125--163

EN

Defining a condenser in a locally compact space as a locally finite, countable collection of Borel sets Ai, i ϵ I, with the sign si = ±1 prescribed such that Ai ∩ Aj = Ø; whenever sisj = −1, we consider a minimum energy problem with an external field over infinite-dimensional vector measures (µi) i ϵ I, where µi is a suitably normalized positive Radon measure carried by Ai and such that µi ≤ ξi for all i ϵ I0, I0 ⊂ I and constraints ξi, i ϵ I0, being given. If I0 = Ø, the problem reduces to the (unconstrained) Gauss variational problem, which is in general unsolvable even for a condenser of two closed, oppositely signed plates in R3 and the Coulomb kernel. Nevertheless, we provide sufficient conditions for the existence of solutions to the stated problem in its full generality, establish the vague compactness of the solutions, analyze their uniqueness, describe their weighted potentials, and single out their characteristic properties. The strong and the vague convergence of minimizing nets to the minimizers is studied. The phenomena of non-existence and non-uniqueness of solutions to the problem are illustrated by examples. The results obtained are new even for the classical kernels on Rn, n ≥ 2, and closed Ai, i ϵ I, which is import ant for applications.

10

Analysis of glass forming ability using percolation concept and tunability of physical parameters of a-Ge12Se76 – xAs12Bix glassy semiconductors

Sharma I., Sunder S.

Materials Science Poland

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2018

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Vol. 36, No. 2

242--254

EN

Glass forming ability of lone-pair semiconductors was analyzed for (x = 0, 2, 4, 6, 8, 10) system. Values of lone pair electrons L were calculated using average coordination number of valence electrons. These values were found to decrease, as the system was moving towards the rigid region. L > 3 values showed vitreous state. Deviation of the stoichiometry confirmed the chalcogen-rich region. A linear correlation was found between the mean bond energy and glass transition temperature. Chemical Bond Approach model was applied to calculate the cohesive energy of the system. A linear relationship was found to exist between the cohesive energy and the theoretical band gap, calculated using Shimakawa relation. A decrease in both parameters was explained on the basis of average stabilization energy and electronegativity of the system. The density values were found to increase and may account for higher refractive index of the system. Large Bohr radius of the Bi atom accounted for an increase in the polarizability. Other parameters viz. degree of covalency, packing density, compactness, molar volume, free volume percentage, excess volume and polaron radius were also calculated. An effort was made to correlate the effect of Bi addition to Ge12Se76 – xAs12Bix lone-pair semiconductor on the basis of the structure of the glassy matrix or the connectedness of the material.

11

Sharp and laterally constrained multitrace impedance inversion based on blocky coordinate descent

Wang Y., Lin W., Cheng S., She B., Hu G., Liu W.

Acta Geophysica

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2018

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Vol. 66, no. 4

623--631

EN

Seismic impedance inversion is a well-known method used to obtain the image of subsurface geological structures. Utilizing the spatial coherence among seismic traces, the laterally constrained multitrace impedance inversion (LCI) is superior to trace-by-trace inversion and can produce a more realistic image of the subsurface structures. However, when the traces are numerous, it will take great computational cost and a lot of memory to solve the large-scale matrix in the multitrace inversion, which restricts the efficiency and applicability of the existing multitrace inversion algorithm. In addition, the multitrace inversion methods are not only needed to consider the lateral correlation but also should take the constraints in temporal dimension into account. As usual, these vertical constraints represent the stratigraphic characteristics of the reservoir. For instance, total-variation regularization is adopted to obtain the blocky structure. However, it still limits the magnitude of model parameter variation and therefore somewhat distorts the real image. In this paper, we propose two schemes to solve these issues. Firstly, we introduce a fast algorithm called blocky coordinate descent (BCD) to derive a new framework of laterally constrained multitrace impedance inversion. This new BCD-based inversion approach is fast and spends fewer memories. Next, we introduce a minimum gradient support regularization into the BCD-based laterally constrained inversion. This new approach can adapt to sharp layer boundaries and keep the spatial coherence. The feasibility of the proposed method is illustrated by numerical tests for both synthetic data and field seismic data.

12

Numerical analysis of the foods nature effect on the mechanical behavior of dental implants

Sifi M., Serier B., Merdji A., Benaissa A, Mootanah R.

Mechanics and Mechanical Engineering

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2017

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Vol. 21, nr 4

1021--1032

EN

This study focuses on a three-dimensional numerical analysis by the finite element method, the mechanical behavior of the dental prosthesis implant composed of a single implant. The effect of the nature of food on the level and distribution of the Von Mises equivalent stress generated in the bone and the elements that constitute this prosthesis have been highlighted. It has been shown that this level is particularly important that the Crushed masticated foods are rigid. This work was carried out to answer questions whose purpose was to analyze the risk of overload in the mandibular region. Loads transfer mechanisms and the possible failure of osseointegrated implants, the shape of the implant, the geometrical and mechanical properties of the placement site and bone resorption of the crest. A proper estimation of these effects allows the correct design of the implant.

13

Design Supported by Many-Sorted First-Order Logic Constraints with Aggregate Operators

Palacz W.

Machine Dynamics Research

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2017

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Vol. 41, No. 4

43--50

EN

This paper is concerned with automatic checking of design constraints. It continues the work presented in (Palacz, 2015) by proposing an enhanced version of the constraint specification language described in that paper. The language is based on many-sorted first-order logic formulas - the proposed extension adds five new operators which calculate aggregates of single values. This considerably increases the expressive power of the language and makes it applicable to a wider range of design tasks.

14

Reconstructing Binary Matrices under Window Constraints from their Row and Column Sums

Alpers A., Gritzmann P.

Fundamenta Informaticae

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2017

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Vol. 155, nr 4

321--340

EN

The present paper deals with the discrete inverse problem of reconstructing binary matrices from their row and column sums under additional constraints on the number and pattern of entries in specified minors. While the classical consistency and reconstruction problems for two directions in discrete tomography can be solved in polynomial time, it turns out that these window constraints cause various unexpected complexity jumps back and forth from polynomialtime solvability to NP-hardness.

15

Representing syntax by means of properties : a formal framework for descriptive approaches

Blache P.

Journal of Language Modelling

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2016

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Vol. 4, No. 2

183--224

EN

Linguistic description and language modelling need to be formalny sound and complete while still being supported by data. We present a linguistic framework that bridges such formal and descriptive requirements, based on the representation of syntactic information by means of local properties. This approach, called Property Grammars, provides a formal basis for the description of specific characteristics as well as entire constructions. In contrast with other formalisms, all information is represented at the same level (no property playing a more important role than another) and independently (any property being evaluable separately). As a consequence, a syntactic description, instead of a complete hierarchical structure (typically a tree), is a set of multiple relations between words. This characteristic is crucial when describing unrestricted data, including spoken language. We show in this paper how local properties can implement any kind of syntactic information and constitute a formal framework for the representation of constructions (seen as a set of interacting properties). The Property Grammars approach thus offers the possibility to integrate the description of local phenomena into a general formal framework.

16

Controllability criteria for time-delay fractional systems with a retarded state

Sikora B.

International Journal of Applied Mathematics and Computer Science

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2016

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Vol. 26, no. 3

521--531

EN

The paper is concerned with time-delay linear fractional systems with multiple delays in the state. A formula for the solution of the discussed systems is presented and derived using the Laplace transform. Definitions of relative controllability with and without constraints for linear fractional systems with delays in the state are formulated. Relative controllability, both with and without constraints imposed on control values, is discussed. Various types of necessary and sufficient conditions for relative controllability and relative U-controllability are established and proved. Numerical examples illustrate the obtained theoretical results.

17

Performance evaluation of iterative minimization methods for nonlinear programming problems with constraints

Szukalski M., Horla D.

Studia z Automatyki i Informatyki

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2015

|

T. 40

7--36

EN

The paper considers performance issues of a class of iterative minimization methods for nonlinear problems with constraints, leading to presentation of information of the algorithm that has superior properties for a given size of the problem.

PL

W artykule poruszono zagadnienie szybkości działania metod minimalizacji funkcji nieliniowej przy ograniczeniach za pomocą metod iteracyjnych. Wskazano algorytmy, które działają szybciej dla zadań o określonej strukturze.

18

System zabezpieczenia logistycznego sytuacji kryzysowej część 2 - model decyzyjny

Ficoń K.

Gospodarka Materiałowa i Logistyka

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2015

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nr 5

159--172

PL

W pracy został zaprezentowany model decyzyjny systemu zabezpieczenia logistycznego sytuacji kryzysowych stanowiący dopełnienie modelu identyfikacyjnego przedstawionego w części 1. Zgodnie z metodologią badań systemowych model decyzyjny zawiera: formułę funkcji kryterium, zbiór ograniczeń i warunków brzegowych oraz formuły budowania docelowych planów i harmonogramów działań operacyjnych. Szczególnie krytyczne ograniczenia generuje wielka dynamika zdarzeń kryzysowych i związana z nią presja czynnika czasowego oraz konieczność spełnienia rygorów zasady Just in Time.

EN

This paper was presented to the decision-making model of logistics security system constitutes complement emergency identification model presented in part 1. According to the methodology of systems analysis decision model contains a formula criterion function, a set of constraints and boundary conditions and the formula of the target building plans and schedules operations. Particularly critical constraints generates a great event dynamics of crisis and the associated pressure on the time factor and the need to meet the rigors of rules Just in Time.

19

Przestrzenno-środowiskowe determinanty rozwoju energetyki wiatrowej w województwie podlaskim

Kolendo Ł.

Ekonomia i Środowisko

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2015

|

nr 3

42--55

PL

W polskiej i zagranicznej literaturze przedmiotu wielokrotnie poruszano zagadnienia związane z doborem zestawu czynników lokalizacyjnych pozwalających na wskazanie przestrzeni właściwych do posadowienia elektrowni wiatrowych. Tego typu badania podejmowano lokalnie w odniesieniu do obszarów województw: podkarpackiego, dolnośląskiego, lubelskiego, pomorskiego, opolskiego oraz warmińsko-mazurskiego. W kontekście tych uwarunkowań, celem niniejszej pracy jest próba wyznaczenia na terenie województwa podlaskiego obszarów predysponowanych do rozwoju energetyki wiatrowej w oparciu o przyjęty zestaw kryteriów wykluczających, a także konfrontacja uzyskanych wyników z obecnym stanem wykorzystania energii ze źródeł odnawialnych.

EN

The paper proposes an analytical approach for supporting the choice of the suitable areas for wind energy development. At the beginning the actual state of renewable energy resources use in Poland and podlaskie voivodeship was analyzed. Then the predisposed locations for wind energy development areas were chosen from the study area based on infrastructural, environmental, socio-cultural and hydrogeological constraints. Spatial research problem was solved by author, using tools of Geographic Information Systems.

20

Implementation of A Geometric Constraint Regularization For Multibody System Models

Müller A.

Archive of Mechanical Engineering

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2014

|

Vol. LXI, nr 2

365--383

EN

Redundant constraints in MBS models severely deteriorate the computational performance and accuracy of any numerical MBS dynamics simulation method. Classically this problem has been addressed by means of numerical decompositions of the constraint Jacobian within numerical integration steps. Such decompositions are computationally expensive. In this paper an elimination method is discussed that only requires a single numerical decomposition within the model preprocessing step rather than during the time integration. It is based on the determination of motion spaces making use of Lie group concepts. The method is able to reduce the set of loop constraints for a large class of technical systems. In any case it always retains a sufficient number of constraints. It is derived for single kinematic loops.

PL

Nadmiarowe więzy w układach wieloczłonowych (MBS) poważnie pogarszają wydajność obliczeniową i dokładność numerycznych metod symulacji systemów MBS. Klasycznym podejściem do rozwiązania tego problemu jest numeryczna dekompozycja Jakobianu więzów w kolejnych krokach całkowania cyfrowego. Dekompozycje takie są jednak kosztowne obliczeniowo. W artykule zaprezentowano metodę eliminacji, która wymaga tylko pojedynczej dekompozycji na etapie wstępnego przetwarzania modelu, a nie w trakcie integracji czasowej. Metoda jest oparta na wyznaczaniu przestrzeni ruchu przy wykorzystaniu koncepcji grup Liego. Pozwala ona zredukować zbiór więzów pętli dla szerokiej klasy systemów technicznych, przy czym w każdym przypadku zachowuje ona dostateczną liczbę więzów. Metoda została wyprowadzona i zilustrowana dla pojedynczych pętli kinematycznych.