This paper introduces a new, reference trajectory following, sliding-mode control strategy for disturbed discrete-time systems. The strategy uses an external trajectory generator based on a switching type reaching law. The trajectory following strategy not only ensures all the properties of the quasi-sliding-mode as defined by Gao et al., but with a certain choice of the control parameters it also guarantees a significant reduction of the quasisliding-mode band width and the errors of all the state variables. This paper also considers the problem of error calculation in the discrete-time, reaching law based sliding-mode control systems. It is shown that the limitation of the sliding variable in the sliding phase directly results in bounded errors of all state variables. The results are verified with a simulation example.
This paper presents a new reaching law-based model reference quasi-sliding mode control strategy for discrete-time dynamical systems. The strategy ensures the quasi-sliding mode attributes defined in the seminal paper of Gao et al, but at the same time, it offers essentially improved system robustness. In particular, it is demonstrated that the application of the reference model results in the decreased width of the quasi-sliding mode band and guarantees smaller errors of all state variables. KEYWORDS discrete-time systems, model reference sliding mode control, reaching law 1440
The paper addresses the problem of chattering elimination in sliding mode control for sampled data dynamical systems and proposes an innovative control scheme. The key to the proposed control method is utilizing a pregenerated nonswitching type reference sliding variable profile to control the disturbed plant. As sampled data systems contain sample-and-hold devices in their input and output channels, we carry out a discrete time analysis. We consider the discretization effects on the controller in two aspects: the pace of convergence of the system and the ultimate band width. Consequently, in the reference sliding variable generator, we analyse two reaching laws, differently adapting to changes of the controller’s frequency. We prove that this approach not only minimizes the chattering phenomenon but also provides a reduction of the quasi-sliding mode band width, which in general case remains of O(T) order. Furthermore, the proposed control method incorporates a disturbance compensation algorithm, which results in the ultimate band width of O(T2) order. Finally, we also show that a certain selection of the sliding plane guarantees limitation of all the state variables’ errors to O(T2) order as well. Therefore, the proposed control algorithm significantly improves the system’s robustness.
STRESZCZENIEWiedza mieszkańców wsi na temat raka jelita grubego Cel pracy. Analiza wiedzy, dorosłych mieszkańców wsi, na temat raka jelita grubego. Materiał i metodyka. W badaniu wzieło udział 100 pełnoletnich mieszkańców wsi. Badania były dobrowolne i anonimowe badania ankietowe. Kwestionariusz ankiety zawierał 13 pytań. Zebrany materiał poddano analizie opisowej. Wartości analizowanych parametrów zostały zmierzone w skali nominalnej i scharakteryzowane za pomocą liczebności oraz wartości procentowych. Wyniki. Większość badanych nie znała sposobów zapobiegania rakowi jelita grubego. Większość z nich wskazała kolonoskopię jako badanie najbardziej znaczące w diagnostyce tego nowotworu. Ogromny odsetek ankietowanych uznał badania przesiewowe za trudno dostępne. Prawie połowa badanych za główne źródło wiedzy o chorobie uznała środki masowego przekazu. W subiektywnej ocenie uznali swoją wiedzę na temat raka jelita grubego jako niewystarczającą. Wnioski. Badana grupa posiadała niską wiedzę na temat raka jelita grubego. Zdaniem respondentów istnieje trudność w dostępie do badań skriningowych dla ludności z terenów wiejskich. Mieszkańcy wsi nisko ocenili edukację zdrowotną prowadzoną przez profesjonalistów ochrony zdrowia.Słowa kluczowe: wiedza, rak jelita grubego, profilaktyka ABSTRACT The country dwellers' knowledge of colon cancer Aim. The analysis of the adult country dwellers' knowledge of colon cancer. Material and methods. 100 adult inhabitants of Oleśnica (a village in Masovian Voivodeship of Poland.) They filled out a voluntary and anonymous questionnaire survey consisting of 13 questions. The collected material has been analyzed and described. The values of the analyzed parameters have been measured in a nominal scale and characterized with the use of numbers and percentages.Results. The majority of respondents were not aware of any ways to prevent colon cancer. Most of them found colonoscopy the most significant diagnostic examination. A large proportion of the people surveyed claimed that preventive screening was not easily available. Nearly a half of the subjects pointed to mass media as the most reliable source of knowledge about colon cancer. Also, they subjectively claimed that their knowledge about colon cancer was not sufficient. Conclusions. The surveyed group had little knowledge of colon cancer. According to the respondents there is difficulty in an access to preventive screening for country dwellers. Country dwellers did not value the health education provided by healthcare professionals.
The paper explores possibility of improving Support Vector Machine-based classification performance by introducing an input data dimensionality reduction step. Feature extraction by means of two different kernel methods are considered: kernel Principal Component Analysis (kPCA) and Supervised kernel Principal Component Analysis. It is hypothesized that input domain transformation, aimed at emphasizing between-class differences, would facilitate classification problem. Experiments, performed on three different datasets show that one can benefit from the proposed approach, as it provides lower variability in classification performance at similar, high recognition rates.
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