Wyniki wyszukiwania - Biblioteka Nauki

1

Performance evaluation based fault tolerant control with actuator saturation avoidance

100%

Boussaid B. , Aubrun C. , Abdelkrim M. , Gayed M.

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tom 21

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nr 3

457-466

EN

In this paper, a new approach regarding a reconfigured system is proposed to improve the performance of an active fault tolerant control system. The system performance is evaluated with an intelligent index of performance. The reconfiguration mechanism is based on a model predictive controller and reference trajectory management techniques. When an actuator fault occurs in the system, a new degraded reference trajectory is generated and the controller calculates new admissible controls. A constraint set and cost function are established to avoid actuator saturation and reduce the control energy spent in closed loop dynamics. The effectiveness of the proposed method is illustrated using a hydrothermal system subject to actuator faults and constraints on actuator dynamic ranges.

2

Optimisation of the performance of a pyrolysis reactor for G50 chips

100%

Dhaundiyal A. , Singh S.

Archives of Thermodynamics

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2020

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tom Vol. 41, no 1

245--263

EN

The aim of any industrial plant, which is dealing in the energy sector, is to maximise the revenue generation at the lowest production cost. It can be carried out either by optimizing the manpower or by improving the performance index of the overall unit. This paper focuses on the optimisation of a biomass power plant which is powered by G50 hardwood chips (Austrian standard for biomass chips). The experiments are conducted at different operating conditions. The overall effect of the enhanced abilities of a reactor on the power generation is examined. The output enthalpy of a generated gas, the gas yield of a reactor and the driving mechanism of the pyrolysis are examined in this analysis. The thermal efficiency of the plant is found to vary from 44 to 47% at 400°C, whereas it is 44 to 48% for running the same unit at 600°C. The transient thermal condition is solved with the help of the lumped capacitance method. The thermal efficiency of the same design, within the constraint limit, is enhanced by 5.5%, whereas the enthalpy of the produced gas is magnified by 49.49% through nonlinear optimisation. The temperature of biomass should be homogenous, and the ramping rate must be very high. The 16% rise in temperature of the reactor is required to reduce the mass yield by 20.17%. The gas yield of the reactor is increased by up to 85%. The thermal assessment indicates that the bed is thermally thin, thus the exterior heat transfer rate is a deciding factor of the pyrolysis in the reactor.

3

Control system with the specific performance index for an evaporator

100%

Świtalski S.

Control and Cybernetics

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1999

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tom Vol. 28, no 2

315--329

EN

In some cases the classical performance indexes are not adequate for the performance evaluation of the concentration control systems. Therefore, the specific performance index is proposed in this paper. This index depends on the product of the product flow rate and some function of the deviation of the product concentration from the set point. In order to minimize this performance index the special control system is proposed. This special control system used to the forced circulation evaporator is studied using simulation techniques. The simulation results show that the system described in this paper produces the performance index less than classical control system.

4

Mathematical model of operational management technological complex continuous type

100%

Ladanyuk A. , Prokopenko T. , Reshetiuk V.

Annals of Warsaw University of Life Sciences - SGGW. Agriculture

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2017

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nr 69

5

Uogólniony wskaźnik jakości dla układów regulacji cyfrowej

100%

Mitkowski W. , Oprzędkiewicz K.

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2003

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tom T. 7, z. 1-2

165-172

PL

W pracy omówiono propozycję nowego uogólnionego wskaźnika jakości dla układów regulacji cyfrowej. Proponowany wskaźnik jakości łączy w sobie dwa różne i często sprzeczne czynniki, które muszą zawsze być uwzględniane podczas syntezy algorytmu sterowania. Pierwszym z nich jest jakość regulacji oceniana na podstawie klasycznych wskaźników jakości (np. czas regulacji lub wskaźniki całkowe). Drugim czynnikiem jest czynnik uwzględniający aspekt ekonomiczny realizacji algorytmu. W prezentowanej pracy czynnik ekonomiczny został powiązany ze złożonością obliczeniową algorytmu. Z kolei złożoność obliczeniowa algorytmu jest zależna od modelu matematycznego algorytmu sterowania, opisanego dyskretnym równaniem stanu lub transmitancją dyskretną. Jako przykład rozważono syntezę układu regulacji z predyktorem Smitha dla obiektu o parametrach rozłożonych. Zastosowanie proponowanego wskaźnika jakości pozwoliło w tym wypadku na wyznaczenie najważniejszego parametru dyskretnego układu regulacji, jakim jest okres próbkowania algorytmu.

EN

In paper the proposition of a new general performance index for digital control systems is discussed. The proposed performance index covers two different and often contradictory factors, which have always to be considered during construction of the real digital control system. The first is the control performance estimated with the typical performance indexes use (for example: the settling time, the integral square performance indexes, u.a.). The second is the factor considering the economic aspect of control algorithm's realisation. In presented paper as the economic factor was connected with the computational complexity of the control algorithm. Further, the algorithm's complexity depends on it's mathematical model described by the discrete state-space equation or by the discrete transfer function. As an example the synthesis of the digital Smith predictor for the distributed parameter object was considered. The use of the proposed general performance index allowed us to assign the optimal sample time, which is the most important parameter of digital control system.

6

A graphical interpretation of a fractional-order backward-difference/Sum

86%

Ostalczyk P.

Pomiary Automatyka Kontrola

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2010

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tom R. 56, nr 5

418-422

EN

In this paper an attempt to formulate a graphical interpretation of a fractional-order backward difference/sum (FOBD/S) is presented. The FOBD/S is a very important mathematical tool in dynamical systems identification and control strategies synthesis. A good understanding of the FOBD/S operation may lead to a definition of new performance indices grounded on FOBSs preserving desired transients.

PL

Artykuł jest próbą określenia graficznej interpretacji różnicy i sumy wstecznej niecałkowitego rządu (R/SNCR). R/SNCR staje się ważnym narzędziem matematycznym wykorzystywanym w identyfikacji oraz sterowania obiektami dynamicznymi. Dobre zrozumienie operacji R/SNCR, analogiczne do graficznej interpretacji sumy i różnicy wstecznej pierwszego rzędu, w oczywisty sposób zwiększy obszar zastosowań R/SNCR. W niniejszej pracy pojęcie SNCR pozwoliło sformułować definicję nowych całkowych wskaźników jakości, w których rząd całkowania reprezentuje tzw. funkcje wagi (kary) stosowane w całkowych wskaźnikach jakości regulacji. Odpowiedni dobór rzędu całkowania (numerycznego sumowania) całkowego wskaźnika jakości pozwoli zaprojektować regulator zapewniający wymagane przebiegi przejściowe zamkniętych układów regulacji. Rozważania zilustrowane zostały doborem optymalnego, względem przyjętego kryterium, klasycznego regulatora PI w liniowym układzie regulacji.

7

Evaluation of a high-precision digital multimeter by the laboratory of calibration of multifunction electrical instruments of INRIM

86%

Galliana F. , Lanzillotti M.

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tom 26

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nr 2

8

Minimum energy control of degenerate Cauchy problem with skew-Hermitian pencil

86%

Benaoued M. , Bouagada D.

Journal of Applied Analysis

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2022

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tom Vol. 28, nr 2

251--261

EN

The present research paper deals with the effectiveness of the control of an infinite-dimensional degenerate Cauchy problem with variable operator coefficients, skew-Hermitian pencil and bounded input condition. This study explores the minimum energy control problem. The investigation follows a set of methods to examine the procedure for developing a new result to solve the problem. Indeed, by the use of decomposition transformation of the considered system and the application of the Gramian operator, the formula of the process for controlling the system with minimum energy is obtained. Afterwards, a procedure to compute the optimal input for minimizing the performance index is then proposed. In a nutshell, the obtained results indicate that optimal control for minimizing the performance index ensures the solution of the minimum energy control of an infinite-dimensional degenerate Cauchy problem.

9

Pokazateli gazoturbinnojj ustanovki s termokhimicheskojj regeneraciejj tepla

86%

Cherednichenko O. , Oschip O.

Motrol. Motoryzacja i Energetyka Rolnictwa

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2013

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tom 15

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nr 2

10

Rezul'taty ehksperimental'nogo issledovanija parametrov vibropluga s gidravlicheskimi vibratorami

86%

Loveykin V. , Dyachenko L.

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nr 4

11

The influence of stocking density on the performance of pigs and welfare

86%

Novak P. , Paseka A. , Bernardy J. , Odehnal J. , Slegerova S. , Novak L.

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2004

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tom 52

EN

The objective of this research was to determine the effect of group size on pig performance. A field study was carried out during 15 months. The building had 52 pens in total, which housed grower pigs to 35-38 kg body weight. During the first 8 months the average number of animals was 726. During the time of most significant decrease of performance in months 9 and 10 the average number went up to 751 animals. A reduction in total feed intake was observed during months 9, 10 and 11 and the average consumption of compound feed per animal and day dropped to 1.68, 1.32 and 1.09 kg. Consequently the weight gain decreased to 615, 535 and 505 g, respectively. The example showed the negative influence of overstocking of grower pigs on the essential performance indicators, such as weight gain, compound feed consumption per feeding day and feed conversion. The number of animals in pens should be decided on the basis of stocking density which influence positively performance. The size of the lying area for this particular age group and this particular building should be between 0.48 and 0.51 sq m per animal.

PL

Celem badań było określenie wpływu efektu obsady zwierząt w budynku na wyniki użytkowości trzody chlewnej. Badania terenowe trwały 15 miesięcy. Obserwowany budynek posiadał ogółem 52 kojce do utrzymywania warchlaków do masy ciała 35-38 kg. W pierwszych 8 miesiącach średnia obsada budynku wynosiła 726 szt. W okresie istotnego pogorszenia się wyników użytkowości warchlaków, w 9 i 10 miesiącu, średnia obsada zwiększyła się do 751 zwierząt. Zaobserwowano zmniejszone zużycie paszy w miesiącach 9, 10 i 11 i korespondowało to ze zmniejszonym średnim dobowym pobraniem paszy przez warchlaka, które obniżyło się odpowiednio do 1,68; 1,32 i 1,09 kg. Odpowiednio obniżeniu uległy średnie przyrosty dobowe do 615, 535 i 505 g. Na przykładzie tym wykazano negatywny wpływ przegęszczenia obsady warchlaków na podstawowe wskaźniki użytkowości tucznej, takie jak przyrost masy ciała, pobranie paszy na dobę i konwersję paszy na przyrost masy ciała. O zagęszczeniu zwierząt w kojcach powinno się decydować w oparciu o obsadę, która wpływa korzystnie na wyniki użytkowości. Dla grupy wiekowej warchlaków w badanym budynku określono optymalną wielkość powierzchni legowiskowej dla 1 sztuki na 0,48 -0,51 m2.

12

Evaluation of a high-precision digital multimeter by the laboratory of calibration of multifunction electrical instruments of INRIM

86%

Galliana F. , Lanzillotti M.

Metrology and Measurement Systems

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2019

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tom Vol. 26, nr 2

283--296

EN

A metrological verification of a high precision digital multimeter was made by the laboratory of calibration of programmable electrical multifunction instruments of the National Institute of Metrological Research (INRIM) in order to verify its accuracy and stability. The instrument had been tested for a period of six months for five low-frequency electrical quantities (DC and AC Voltage and Current and DC Resistance). Its stability and precision were compared with the accuracy specifications of the manufacturer. As a new approach, a performance index of the DMM was introduced and evaluated for each examined measurement point. The DMM showed a satisfactory agreement with its specifications to be considered at the level of other top-class DMMs and even better in some measurements points.

13

Performance evaluation based fault tolerant control with actuator saturation avoidance

72%

Boussaid B. , Aubrun C. , Abdelkrim M. N. , Ben Gayed M. K.

International Journal of Applied Mathematics and Computer Science

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2011

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tom Vol. 21, no 3

457-466

EN

In this paper, a new approach regarding a reconfigured system is proposed to improve the performance of an active fault tolerant control system. The system performance is evaluated with an intelligent index of performance. The reconfiguration mechanism is based on a model predictive controller and reference trajectory management techniques. When an actuator fault occurs in the system, a new degraded reference trajectory is generated and the controller calculates new admissible controls. A constraint set and cost function are established to avoid actuator saturation and reduce the control energy spent in closed loop dynamics. The effectiveness of the proposed method is illustrated using a hydrothermal system subject to actuator faults and constraints on actuator dynamic ranges.

14

Enhancing effectiveness of linking EFQM excellence model criteria by means of balanced scorecard in the wood processing businesses

72%

Paulova I.

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tom 24

15

Wskaźniki osiągnięć w praktyce zarządzania lokalnej administracji publicznej

72%

Nowak J.

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2007

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tom 06

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nr 3

16

Solvent retention capacity (src’s) profiles and technological quality parameters of selected Czech wheat varieties

72%

Svec I. , Hruskova M. , Karas J.

Electronic Journal of Polish Agricultural Universities. Series Food Science and Technology

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2013

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tom 16

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nr 3

17

Uproszczone metody oceny gospodarki paszowej

58%

Ufnowska J.

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nr 10

24-26

18

Influence of qualitative and dimensional classification of Pinewood raw material as an efficiency indicator in the production of selected timber assortments

58%

Wieruszewski M. , Mirski R. , Kawalerczyk J. , Trocinski A.

Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology

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2019

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tom 107

19

Effect of dietary supplementation with extracts of rosemary, olive leaves, pine bark and quercetin on selected performance indices of broiler chickens and microbiological status of their ileum

58%

Sierzant K. , Orda J. , Korzeniowska M. , Malicki A.

Medycyna Weterynaryjna

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2019

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tom 75

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nr 04

EN

A total of 180 1-day-old male Hubbard Flex broiler chickens were used in a 32-day model experiment to determine the effects of dietary supplementation with quercetin (Q) and with polyphenolic extracts of rosemary (RO), olive leaves (OL) and pine bark (PB) on the performance of the birds and the microbiological status of their ileum. The chickens were randomly allocated into 9 groups: the control group (with 6 replicates, 6 birds per cage) and 8 treatment groups (with 3 replicates in each, 6 birds per cage), and fed ad libitum throughout the experimental period with a basal isoenergetic and isoprotein control diet or with the same basal diet containing two concentrations of RO, OL and PB extracts (2.50 and 5.00 g/kg), and Q (0.25 and 0.50 g/kg). The body weight gain (BWG) and the feed conversion ratio (FCR) were determined during the experiment. At day 32, two randomly selected birds from each cage were slaughtered, and 5-centimetre-long pieces of the ileum beginning from the Meckel's diverticulum were collected to analyze the number of microorganisms in the intestinal content. Chickens’ weight gain and FCR were not affected by the OL-, PB- and Q-enriched diets, but supplementation with RO significantly (P < 0.05) impaired FCR. BWG was significantly (P < 0.05) reduced when chickens were fed with mixtures containing 2.50 and 0.25 g/kg of the polyphenolic additives. The number of CFUs of intestinal microorganisms was not significantly affected (P > 0.05) by the diet modification. However, a large decrease (P > 0.05) was observed in the CFUs of coliform bacteria (up to 96%), E. coli (up to 93%), Lactobacillus spp. (up to 89%), molds and yeasts (up to 95%) and anaerobic Clostridium spp. (up to 52%) in the ileum content of chickens supplemented with the additives containing polyphenols.

20

Evaluation of ecological concrete using multi-criteria ecological index and performance index approach

58%

Kubissa W. , Jaskulski R. , Chen J. , Ng P.-L. , Godlewska W. , Reiterman P.

Architecture Civil Engineering Environment

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2019

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tom Vol. 12, no. 1

97--107

EN

This paper proposes a new method of rational and quantitative assessment of ecological concrete in terms of the ecological impact and engineering performance. The concrete mix is evaluated through the multi-criteria Ecological Index (EI) and Performance Index (PI) approach. The EI accounts for the impact of the concrete on environment including the carbon emission and raw materials usage, whereas the PI accounts for the engineering performance of the concrete such as compressive strength and water sorptivity. Depending on the applications of the concrete, different criteria may be chosen for the evaluation. Concrete mixes reported in the literature comprising different types of cement, supplementary cementitious materials and aggregates are analyzed to illustrate the applicability of the proposed multi-criteria assessment method. It is shown that the proposed method is able to effectively reflect the concurrent ecological impact and engineering performance of concrete mixes, and hence facilitate rational design of ecological concrete to suit practical engineering applications.