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1

Fuzzy fractional order PI controller for a multilevel inverter for grid-connected photovoltaic systems (PV)

Mechgoug Raihane, Boucheritte Wafa, Benguesmia Hani

Przegląd Elektrotechniczny

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2023

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R. 99, nr 8

146--153

EN

These Applications of fractional calculus are becoming more and more effective, adaptable, and have produced positive outcomes in a variety of engineering and scientific domains. In this paper, a fuzzy fractional-order PI-based control approach for grid-connected photovoltaic (PV) systems is presented. The various advantages of multi-level inverters (MLIs) in industrial and grid-connected applications have resulted to their increasing application in recent years. A five-level neutral point (NPC) inverter is used to integrate PV electricity into the electrical grid with minimal harmonic distortions and highest power capacity. The output voltage of the inverter must be maintained in order to connect to a grid, even though that the photovoltaic output voltage varies considerably with solar radiation. To achieve this, three fuzzy fractional order PI (FFOPI)controllers were used to control the inverter output voltage (Vdc), direct current (Id), and quadratic current (Iq) around a reference values. A further comparison is made with the fuzzy PI (FPI). According to research, the FFOPI controller outperforms the FPI controller in terms of performance.

PL

Te zastosowania rachunku ułamkowego stają się coraz bardziej efektywne, elastyczne i dają pozytywne rezultaty w różnych dziedzinach inżynierii i nauki. W tym artykule przedstawiono podejście oparte na rozmytym ułamkowym rzędzie sterowania PI dla systemów fotowoltaicznych (PV) podłączonych do sieci. Różne zalety falowników wielopoziomowych (MLI) w zastosowaniach przemysłowych i podłączonych do sieci spowodowały ich rosnące zastosowanie w ostatnich latach. Falownik z pięciopoziomowym punktem neutralnym (NPC) służy do włączania energii elektrycznej z fotowoltaiki do sieci elektrycznej przy minimalnych zniekształceniach harmonicznych i najwyższej mocy. Napięcie wyjściowe falownika musi być utrzymywane w celu podłączenia do sieci, mimo że napięcie wyjściowe fotowoltaiki znacznie się zmienia w zależności od promieniowania słonecznego. Aby to osiągnąć, zastosowano trzy rozmyte regulatory PI ułamkowego rzędu (FFOPI) do sterowania napięciem wyjściowym falownika (Vdc), prądem stałym (Id) i prądem kwadratowym (Iq) wokół wartości odniesienia. Dalsze porównanie przeprowadza się z rozmytym PI (FPI). Według badań kontroler FFOPI przewyższa kontroler FPI pod względem wydajnoś.

2

Effect of Power Quality on the Performance of Explosion-Proof Transformers in Mining in Vietnam

Do Nhu Y., Ngo Xuan Cuong, Nguyen Thi Hong

Inżynieria Mineralna

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2023

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no. 2, vol. 1

65--69

EN

When meeting customer demand, utility companies must consider power quality. Currently, the industrial power network in general and the underground mine power network in particular have long feeder lines, supplying power to many nonlinear loads and power electronic converters, which reduces power quality. Poor power quality can damage sensitive equipment and lead to costly repairs, leading to lost time, data corruption, and lower productivity. In this paper, a fuzzy system is developed to determine the power quality of the power network for different operating conditions and study its influence on the performance of the explosion-proof transformer in the underground mine power network in Vietnam. The simulations and calculations were performed on Matlab-Simulink software for a three-phase, 630-kVA, 6/1.2 kV explosion-proof transformer in power networks with variable power quality. A fuzzy system is developed with four measurable inputs, including frequency deviation, voltage unbalance factor, total harmonic distortion of supply voltage, total harmonic distortion of current, and an output variable, power quality. The simulation results show that the explosion-proof transformer's performance decreases when the power quality degrades, and the proposed fuzzy system can accurately diagnose this.

3

Agregacja ocen decydentów dla systemu predykcji czasów realizacji procesów budowlanych

Tomczak Michał, Polat Gül

Builder

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2023

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R.27, nr 12

95--99

PL

Jednym z najistotniejszych i najbardziej wymagających zagadnień występujących w ramach inżynierii przedsięwzięć budowlanych jest problem opóźnień w realizacji przedsięwzięć budowalnych. Znaczna liczba czynników ryzyka niezbędnych do uwzględnienia oraz stopień skomplikowania opisu ich wpływu na poszczególne procesy przedsięwzięcia budowlanego sprawiają, że zagadnienie predykcji czasów realizacji procesów i przedsięwzięć budowlanych jest zagadnieniem trudnym. W odpowiedzi na dostrzeżony problem opracowano metodę agregacji ocen decydentów za pomocą rozmytej obwiedni typu 2 rozszerzonego wahającego się rozmytego zbioru terminów lingwistycznych służącą predykcji czasów realizacji procesów budowlanych. W proponowanym podejściu decydenci mogą wyrażać swoje oceny poprzez porównywanie parami, tak jak ma to miejsce w powszechnie akceptowanej metodzie AHP. Decydenci mogą wyrażać swoje preferencje tak swobodnie, jak to możliwe, za pomocą wyrażeń językowych zamiast wartości liczbowych, co jest bliższe ludzkiej kognitywistce i naturze. Decydenci nie muszą ograniczać się do wyrażania preferencji za pomocą pojedynczych słów, mogą używać całych wyrażeń dostarczonych przez zdefiniowaną gramatykę. W celu zobrazowania funkcjonowania metody wykonano predykcję czasów realizacji przykładowego przedsięwzięcia budowlanego z wykorzystaniem opracowanej metody.

EN

One of the most important and challenging issues occurring in construction project engineering is the problem of delays in the execution of construction projects. The significant number of risk factors necessary to take into account and the complexity of describing their impact on the various processes of a construction project make the issue of predicting the execution times of construction processes and projects a difficult one. In response to the perceived problem, a method of aggregating decision makers' assessments using a fuzzy envelope type-2 extended hesitant fuzzy set of linguistic terms was developed for predicting the execution times of construction processes. In the proposed approach, decision makers can express their evaluations through pairwise comparisons, as in the widely accepted AHP method. Decision makers can express their preferences as freely as possible using linguistic expressions instead of numerical values, which is closer to human cognition and nature. Decision makers do not have to limit themselves to expressing preferences with single words, they can use whole expressions provided by a defined grammar. In order to illustrate how the method works, a prediction of the execution times of an example construction project was made using the developed method.

4

A cloud-based urban monitoring system by using a quadcopter and intelligent learning techniques

Khanmohammadi Sohrab, Samadi Mohammad

Journal of Automation Mobile Robotics and Intelligent Systems

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2022

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Vol. 16, No. 2

11--19

EN

The application of quadcopter and intelligent learning techniques in urban monitoring systems can improve flexibility and efficiency features. This paper proposes a cloud-based urban monitoring system that uses deep learning, fuzzy system, image processing, pattern recognition, and Bayesian network. The main objectives of this system are to monitor climate status, temperature, humidity, and smoke, as well as to detect fire occurrences based on the above intelligent techniques. The quadcopter transmits sensing data of the temperature, humidity, and smoke sensors, geographical coordinates, image frames, and videos to a control station via RF communications. In the control station side, the monitoring capabilities are designed by graphical tools to show urban areas with RGB colors according to the predetermined data ranges. The evaluation process illustrates simulation results of the deep neural network applied to climate status and effects of the sensors’ data changes on climate status. An illustrative example is used to draw the simulated area using RGB colors. Furthermore, circuit of the quadcopter side is designed using electric devices.

5

Fuzzy Brain Emotional Controller for Heart Disease Diagnosis

Pham Duc Hung, Nguyen Viet-Ngu, Le Thi Minh-Tam

Annals of Computer Science and Information Systems

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2022

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Vol. 33

33--36

EN

This article provides a new way for classifying heart disease. A classifier using a controller for brain emotional learning and a fuzzy system is presented. The controller's parameter updating laws are built using the gradient descent method. The method's convergence and stability are ensured by the Lyapunov function. Using the heart disease dataset from the University of California, Irvine (UCI), the performance of the system is examined. In addition, a comparison with different classifiers is provided. The outcomes of our experiments illustrate the efficacy of our strategy.

6

Performance analysis of rough set–based hybrid classification systems in the case of missing values

Nowicki Robert K., Seliga Robert, Żelasko Dariusz, Hayashi Yoichi

Journal of Artificial Intelligence and Soft Computing Research

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2021

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Vol. 11, No. 4

307--318

EN

The paper presents a performance analysis of a selected few rough set–based classification systems. They are hybrid solutions designed to process information with missing values. Rough set-–based classification systems combine various classification methods, such as support vector machines, k–nearest neighbour, fuzzy systems, and neural networks with the rough set theory. When all input values take the form of real numbers, and they are available, the structure of the classifier returns to a non–rough set version. The performance of the four systems has been analysed based on the classification results obtained for benchmark databases downloaded from the machine learning repository of the University of California at Irvine.

7

A numerically efficient fuzzy MPC algorithm with fast generation of the control signal

Marusak Piotr M.

International Journal of Applied Mathematics and Computer Science

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2021

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Vol. 31, no. 1

59--71

EN

Model predictive control (MPC) algorithms are widely used in practical applications. They are usually formulated as optimization problems. If a model used for prediction is linear (or linearized on-line), then the optimization problem is a standard, i.e., quadratic, one. Otherwise, it is a nonlinear, in general, nonconvex optimization problem. In the latter case, numerical problems may occur during solving this problem, and the time needed to calculate control signals cannot be determined. Therefore, approaches based on linear or linearized models are preferred in practical applications. A novel, fuzzy, numerically efficient MPC algorithm is proposed in the paper. It can offer better performance than the algorithms based on linear models, and very close to that of the algorithms based on nonlinear optimization. Its main advantage is the short time needed to calculate the control value at each sampling instant compared with optimization-based numerical algorithms; it is a combination of analytical and numerical versions of MPC algorithms. The efficiency of the proposed approach is demonstrated using control systems of two nonlinear control plants: the first one is a chemical CSTR reactor with a van de Vusse reaction, and the second one is a pH reactor.

8

On explainable fuzzy recommenders and their performance evaluation

Rutkowski Tomasz, Łapa Krystian, Nielek Radosław

International Journal of Applied Mathematics and Computer Science

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2019

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Vol. 29, no. 3

595--610

EN

This paper presents a novel approach to the design of explainable recommender systems. It is based on the Wang–Mendel algorithm of fuzzy rule generation. A method for the learning and reduction of the fuzzy recommender is proposed along with feature encoding. Three criteria, including the Akaike information criterion, are used for evaluating an optimal balance between recommender accuracy and interpretability. Simulation results verify the effectiveness of the presented recommender system and illustrate its performance on the MovieLens 10M dataset.

9

Fuzzy system for decision support of post-mining regions reclamation (FSDR)

Król-Korczak Jadwiga, Brzychczy Edyta

Archives of Mining Sciences

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2019

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Vol. 64, no. 1

35--50

EN

Open pit mining of rock minerals and the affected areas requiring further development are a serious challenge for shaping the positive image of the mining industry among the public. The direction and method of post-mining land reclamation are important for this image, which should take into account various factors describing the mining area, including social preferences. The article presents an example solution – fuzzy system (FSDR) – which supports the selection of the direction of reclamation of post-mining areas created after the termination of operations of open pit gravel and sand natural aggregate mines. The article presents selected factors determining the selection of the direction and possible reclamation variants as input and output data of the fuzzy system. The rules base of the developed system, as well as the mechanisms of inference and defuzzification, were also characterized. The application of the developed system is presented on selected examples.

PL

Eksploatacja surowców skalnych metodą odkrywkową oraz pozostające po niej tereny wymagające dalszego zagospodarowania stanowią poważne wyzwanie dla kształtowania pozytywnego wizerunku branży górniczej w odbiorze społecznym. Dla tego wizerunku istotnym jest przede wszystkim kierunek i sposób rekultywacji terenu poeksploatacyjnego, który powinien brać pod uwagę różne czynniki charakteryzujące teren pogórniczy, w tym preferencje społeczne. W artykule zaprezentowano przykład opracowanego rozwiązania – systemu rozmytego (FSDR) – który wspomaga wybór kierunku rekultywacji terenów pogórniczych powstałych po zakończeniu działalności kopalń odkrywkowych kruszyw naturalnych żwirowo – piaszczystych. W artykule przedstawiono wybrane czynniki determinujące wybór kierunku i możliwe warianty rekultywacji jako dane wejściowe i wyjściowe systemu rozmytego. Scharakteryzowano również bazę reguł opracowanego systemu oraz mechanizm wnioskowania i defuzyfikacji. Przedstawiono zastosowanie opracowanego systemu na wybranych przykładach.

10

Implementacja systemu rozmytego przeznaczonego do sterowania instalacją centralnego ogrzewania

Popławski M., Słowik A.

Przegląd Elektrotechniczny

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2018

|

R. 94, nr 7

78--81

PL

Artykuł opisuje implementację systemu rozmytego w mikrokontrolerze, dedykowanego dla instalacji centralnego ogrzewania. System ten dedykowany jest do automatyzacji pracy urządzeń instalacji w zależności od ustawień użytkownika. W tym celu dedykowana architektura kontrolera (sterownika) logiki rozmytej została opracowana. System ten, posiada 3 niezależne wejścia i 2 wyjścia; oraz wbudowane 3 wewnętrzne bloki fuzyfikacji, wnioskowania i wyostrzania.

EN

This paper describes an implementation of a fuzzy system in the microcontroller, dedicated for the central heating installation. This system is dedicated to automate work of devices of heating installation depending on user settings. For this purpose, a dedicated architecture of a fuzzy logic controller system was elaborated. This system has 3 independent inputs and 2 outputs and is composed of 3 internal blocks: fuzzification, inference and defuzzification.

11

PD terminal sliding mode control using fuzzy genetic algorithm for mobile robot in presence of disturbances

Benaziza W., Slimane N., Mallem A.

Journal of Automation Mobile Robotics and Intelligent Systems

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2018

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Vol. 12, No. 2

52--60

EN

This paper presents a new approach in the field of trajectory tracking for nonholonomic mobile robot in presence of disturbances. The proposed control design is constructed by a kinematic controller, based on PD sliding surface using fuzzy sliding mode for the angular and linear velocities disturbances, in order to tend asymptotically the robot posture error to zero. Thereafter a dynamic controller is presented using as a sliding surface design, a fast terminal function (FTF) whose parameters are generated by a genetic algorithm in order to converge the velocity errors to zero in finite time and guarantee the asymptotic stability of the system using a Lyapunov candidate. The elaborated simulation works in the case of different trajectories confirm the robustness of the proposed approach.

12

Optimization of membership function parameters for fuzzy controllers of an autonomous mobile robot using the flower pollination algorithm

Carvajal O. R., Castillo O., Soria J.

Journal of Automation Mobile Robotics and Intelligent Systems

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2018

|

Vol. 12, No. 1

44--49

EN

In this work we describe the optimization of a Fuzzy Logic Controller (FLC) for an autonomous mobile robot that needs to follow a desired path. The FLC is for the simulation of its trajectory, the parameters of the membership functions of the FLC had not been previously optimized. We consider in this work with the flower pollination algorithm (FPA) as a method for optimizing the FLC. For this reason, we use the FPA to find the best parameters with the objective of minimizing the error between the trajectory of the robot and the reference. A comparative study of results with different metaheuristics is also presented in this work.

13

Data-driven techniques for the fault diagnosis of a wind turbine benchmark

Simani S., Farsoni S., Castaldi P.

International Journal of Applied Mathematics and Computer Science

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2018

|

Vol. 28, no. 2

247--268

EN

This paper deals with the fault diagnosis of wind turbines and investigates viable solutions to the problem of earlier fault detection and isolation. The design of the fault indicator, i.e., the fault estimate, involves data-driven approaches, as they can represent effective tools for coping with poor analytical knowledge of the system dynamics, together with noise and disturbances. In particular, the proposed data-driven solutions rely on fuzzy systems and neural networks that are used to describe the strongly nonlinear relationships between measurement and faults. The chosen architectures rely on nonlinear autoregressive models with exogenous input, as they can represent the dynamic evolution of the system along time. The developed fault diagnosis schemes are tested by means of a high-fidelity benchmark model that simulates the normal and the faulty behaviour of a wind turbine. The achieved performances are also compared with those of other model-based strategies from the related literature. Finally, a Monte-Carlo analysis validates the robustness and the reliability of the proposed solutions against typical parameter uncertainties and disturbances.

14

BIBO stabilisation of continuous-time Takagi–Sugeno systems under persistent perturbations and input saturation

Salcedo J. V., Martínez M., García-Nieto S., Hilario A.

International Journal of Applied Mathematics and Computer Science

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2018

|

Vol. 28, no. 3

457--472

EN

This paper presents a novel approach to the design of fuzzy state feedback controllers for continuous-time non-linear systems with input saturation under persistent perturbations. It is assumed that all the states of the Takagi–Sugeno (TS) fuzzy model representing a non-linear system are measurable. Such controllers achieve bounded input bounded output (BIBO) stabilisation in closed loop based on the computation of inescapable ellipsoids. These ellipsoids are computed with linear matrix inequalities (LMIs) that guarantee stabilisation with input saturation and persistent perturbations. In particular, two kinds of inescapable ellipsoids are computed when solving a multiobjective optimization problem: the maximum volume inescapable ellipsoids contained inside the validity domain of the TS fuzzy model and the smallest inescapable ellipsoids which guarantee a minimum *-norm (upper bound of the 1-norm) of the perturbed system. For every initial point contained in the maximum volume ellipsoid, the closed loop will enter the minimum *-norm ellipsoid after a finite time, and it will remain inside afterwards. Consequently, the designed controllers have a large domain of validity and ensure a small value for the 1-norm of closed loop.

15

Zmodyfikowana metoda użycia funkcji progowych w modelach relacyjnych rozmytych map kognitywnych

Słoń G.

Informatyka, Automatyka, Pomiary w Gospodarce i Ochronie Środowiska

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2017

|

T. 7, nr 3

86--89

PL

W artykule przedstawiono sposób wprowadzenia funkcji progowej do modelu Relacyjnej Rozmytej Mapy Kognitywnej, wykorzystującego arytmetykę liczb rozmytych. Funkcyjne przetwarzanie liczby rozmytej powoduje deformacje kształtu liczby i jej nośnika. Zaproponowano „geometryczne” podejście do tego problemu, pozwalające zachować niezmienność nośnika oraz utrzymać kształt przetwarzanej liczby rozmytej przy jednoczesnym odpowiednim przesunięciu centrum tej liczby. Metoda została przetestowana na liczbach rozmytych o różnych funkcjach przynależności.

EN

The article describes the method for introducing a threshold function into a model of the Relational Fuzzy Cognitive Map that uses fuzzy numbers arithmetic. Processing the fuzzy number by function causes deformations of the shape if this number and its support. It is proposed a geometrical approach to this problem, allowing to maintain constancy of the support and to keep the shape of the processed fuzzy number with an appropriate shift of the center of this number. The method was tested on fuzzy numbers with different membership functions.

16

Synthesis of intellectual subsystems of dynamic diagnosis of the condition of turbine units thermal power

Suleimenov A., Suleimenov B., Zhirnova O., Suleimenov A.

Informatyka, Automatyka, Pomiary w Gospodarce i Ochronie Środowiska

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2017

|

T. 7, nr 2

40--43

EN

Technique of creating a sub-line diagnostics status turbine unit thermal power plant based on an analysis of its diagnostic features. Rapid assessment of the technical state of turbine unit allows an early stage to detect the possibility of an emergency and to localize it. It involves the integration of the subsystems of the existing process control system (PCS), which will allow more efficient use of its information, hardware and software. Evaluation of the technical condition of the turbine unit thermal power plant is proposed to determine the use of modern intelligent technologies. The proposed method was used in the development of rapid diagnostic subsystems technical state of turbine of thermal power in Almaty.

PL

Zaproponowano metodykę opracowania podsystemu dynamicznej diagnostyki stanu turbogeneratora elektrowni cieplnej, która bazuje na analizie jego cech diagnostycznych. Dynamiczna ocena technicznego stanu turbogeneratora pozwala na wykrycie we wczesnym stadium awaryjnych sytuacji i jej lokalizacji. Proponuje się integrację tego podsystemu z istniejącym systemem automatycznego sterowania procesem technologicznym, co pozwoli bardziej efektywnie wykorzystać jego informacyjne, techniczne i programowe zabezpieczenia. Ocena technicznego stanu turbogeneratora elektrowni cieplnej proponuje się określić z wykorzystaniem współczesnych technologii inteligentnych. Zaproponowana metodyka była wykorzystana przy opracowaniu podsystemu diagnostyki dynamicznej stanu technicznego turbogeneratora w elektrowni cieplnej w Ałmaty.

17

Optimization of Packing Density of M30 Concrete with Steel Slag as Coarse Aggregate Using Fuzzy Logic

Arivoli M., Malathy R.

Archives of Metallurgy and Materials

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2017

|

Vol. 62, iss. 3

1903--1913

EN

Concrete plays a vital role in the design and construction of the infrastructure. To meet the global demand of concrete in future, it is becoming a challenging task to find suitable alternatives to natural aggregates. Steel slag is a by-product of steel making process. The steel slag aggregates are characterized by studying particle size and shape, physical and chemical properties, and mechanical properties as per IS: 2386-1963. The characterization study reveals the better performance of steel slag aggregate over natural coarse aggregate. M30 grade of concrete is designed and natural coarse aggregate is completely replaced by steel slag aggregate. Packing density of aggregates affects the characteristics of concrete. The present paper proposes a fuzzy system for concrete mix proportioning which increases the packing density. The proposed fuzzy system have four sub fuzzy system to arrive compressive strength, water cement ratio, ideal grading curve and free water content for concrete mix proportioning. The results show, the concrete mix proportion of the given fuzzy model agrees with IS method. The comparison of results shows that both proposed fuzzy system and IS method, there is a remarkable increase in compressive strength and bulk density, with increment in the percentage replacement of steel slag.

18

Implementacja interfejsu użytkownika przeznaczonego do sterowania elektrycznym wózkiem inwalidzkim

Popławski M., Słowik A.

Przegląd Elektrotechniczny

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2016

|

R. 92, nr 8

66--69

PL

W pracy przedstawiono implementację modelu interfejsu użytkownika przeznaczonego do sterowania elektrycznym wózkiem inwalidzkim. W tym celu, dedykowana architektura sterownika systemu rozmytego została zaimplementowana w systemie Raspberry Pi. Głównym zadaniem sterownika systemu rozmytego jest generowanie wyjściowych sygnałów (lewo/prawo – l/p, przód/tył – p/t) sterujących pracą dwóch silników typu D.C. na podstawie sygnałów wejściowych, generowanych przez operatora; w tym celu opracowano wejściowe i wyjściowe zmienne lingwistyczne.

EN

This paper describes an implementation of a user interface model for guiding a wheelchair. For this purpose, a dedicated architecture of fuzzy logic controller was elaborated in Raspberry Pi system. The task of fuzzy logic controller is a generation of output signals (left/ right – l/r, front/back – f/b) steering two permanent magnet DC motors of the wheelchair based on input signals, created by the operator. Input and output linguistic variables and corresponding fuzzy sets were defined.

19

Fuzzy logic-decision-making system dedicated to evaluation of logistics project effectiveness

Pisz I., Łapuńka I.

LogForum

|

2016

|

Vol. 12, no. 3

199--213

EN

Background: Project effectiveness is synonymous with project success. It is measured or assessed in terms of the degree to which project objectives are achieved. This paper presents an approach to evaluating the effectiveness of logistics projects. The starting point is the analysis of the current state of knowledge in the area of assessing project effectiveness, including logistics projects. The purpose of the study was to identify the critical factors determining the success of logistics projects and develop a model of logistics project effectiveness. Methods: The paper is based on the available recent scientific-theoretical research and publications and on practical studies in 25 enterprises seated in Poland. The study carried out by the authors had the form of questionnaires. The authors used a case study to validate the model of fuzzy decision-making system dedicated to estimate the level of logistics project effectiveness. Results: Based on a literature review and research findings, the authors propose the key success factors for logistics project effectiveness. In the paper the authors propose an approach to measure the level of logistics project effectiveness using their model based on fuzzy logic. This model laid the foundations for a fuzzy decision-making system in MATLAB environmental. The paper describes the implementation of the model via a case study. Conclusions: This approach allows for a more detailed description of logistics project effectiveness. The proposed model may be implemented by logisticians in an enterprise and/or supply chain. The approach can be useful to assess the level to which logistics project objectives are achieved - logistics project effectiveness.

PL

Wstęp: Efektywność projektu jest często utożsamiana z sukcesem projektu. Praca podejmuje zagadnienia związane z pomiarem i oceną skuteczności projektów, w tym przypadku projektów logistycznych. Autorzy dokonali analizy literatury tematu. Wyodrębnili kluczowe mierniki sukcesu projektów logistycznych. Na bazie przeprowadzonych badań zbudowano model skuteczności projektów logistycznych, który następnie zaimplementowano w systemie MATLAB. Metody: Praca została przygotowana w oparciu o dostępne badania zarówno teoretyczne, jak i praktyczne. Przeprowadzono badania ankietowe w 25 przedsiębiorstwach w Polsce. Wykorzystano studium przypadku celem ilustracji podjętego problemu. Rezultaty: Przygotowano zestaw mierników umożliwiających dokonanie oceny stopnia skuteczności realizacji celów projektów. Przygotowano model umożliwiający pomiar i ocenę skuteczności działań projektowych, który wykorzystuje logikę rozmytą. Opracowany model został zaimplementowany w systemie MATLAB. Wnioski: Proponowane podejście umożliwia opis problemu pomiaru i oceny skuteczności realizacji projektów logistycznych. Zaproponowane podejście może zostać wykorzystane przez logistyków, menedżerów projektów w ocenie skuteczności działań podejmowanych przez nich projektów logistycznych.

20

A new approach to nonlinear modelling of dynamic systems based on fuzzy rules

Bartczuk Ł., Przybył A., Cpałka K.

International Journal of Applied Mathematics and Computer Science

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2016

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Vol. 26, no. 3

603--621

EN

For many practical weakly nonlinear systems we have their approximated linear model. Its parameters are known or can be determined by one of typical identification procedures. The model obtained using these methods well describes the main features of the system’s dynamics. However, usually it has a low accuracy, which can be a result of the omission of many secondary phenomena in its description. In this paper we propose a new approach to the modelling of weakly nonlinear dynamic systems. In this approach we assume that the model of the weakly nonlinear system is composed of two parts: a linear term and a separate nonlinear correction term. The elements of the correction term are described by fuzzy rules which are designed in such a way as to minimize the inaccuracy resulting from the use of an approximate linear model. This gives us very rich possibilities for exploring and interpreting the operation of the modelled system. An important advantage of the proposed approach is a set of new interpretability criteria of the knowledge represented by fuzzy rules. Taking them into account in the process of automatic model selection allows us to reach a compromise between the accuracy of modelling and the readability of fuzzy rules.