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Wyszukujesz frazę "Condition analysis" wg kryterium: Temat


Tytuł:
Reliability analysis method of coupling optimal importance sampling density and multi-fidelity Kriging model
Autorzy:
Xie, Jiayu
Tian, Zongrui
Zhi, Pengpeng
Zhao, Yadong
Powiązania:
https://bibliotekanauki.pl/articles/24200829.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
reliability analysis
multifidelity model
learning function
stopping condition
Opis:
The commonly used reliability analysis approaches for Kriging-based models are usually conducted based on high-fidelity Kriging models. However, high-fidelity surrogate models are commonly costly. Therefore, in order to balance the calculation expense and calculation time of the surrogate model, this paper proposes a multi-fidelity Kriging model reliability analysis approach with coupled optimal important sampling density (OISD+MFK). First, the MEI learning function is proposed considering the training sample distance, model computation cost, expected improvement function, and model relevance. Second, a dynamic stopping condition is proposed that takes into account the failure probability estimation error. Finally, the optimal importance sampling density is incorporated into the reliability analysis process, which can effectively reduce failure probability estimation error. The results of the study show that the approach proposed in this paper can reduce the calculation cost while outputting relatively accurate failure probability evaluation results.
Źródło:
Eksploatacja i Niezawodność; 2023, 25, 2; art. no. 161893
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Service and maintenance of marine steam turbogenerators with the assistance of vibration diagnostics
Autorzy:
Adamkiewicz, A.
Drzewieniecki, J.
Powiązania:
https://bibliotekanauki.pl/articles/260346.pdf
Data publikacji:
2013
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
turbogenerator
vibration diagnostic
service
maintenance
condition monitoring
signal analysis
Opis:
The paper discusses the problem of maintenance of the marine steam turbogenerator sets used in power systems on VLCC type oil tankers. The analysis of operation, monitoring and applied diagnostic methods of a selected turbogenerator working in the AT series waste energy system produced by Mitsubishi is presented. The analysis focuses on the applied maintenance method and its credibility and effectiveness in terms of technical assessment. The results of the performed maintenance actions and applied operational procedures making use of technical diagnostics and supported by a wider range of measurement capabilities of external service are presented and evaluated. The range of the study includes the readiness, reliability and safety of the use of turbogenerators being the result of the maintenance performed in accordance with the applied strategy of operation.
Źródło:
Polish Maritime Research; 2013, 1; 31-38
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Possibilities of using in Poland the foreign models of predicting the fiscal distress in local government units
Autorzy:
Malinowska-Misiąg, Elżbieta
Powiązania:
https://bibliotekanauki.pl/articles/2128126.pdf
Data publikacji:
2018
Wydawca:
Uniwersytet w Białymstoku. Wydawnictwo Uniwersytetu w Białymstoku
Tematy:
fiscal distress
financial condition of local government units
ratio analysis
Opis:
The aim of the paper is to analyze the usefulness of foreign models of assessing financial condition for predicting financial distress in local governments and to verify whether they may be applied to Polish local government units. The selection of models and indicators was based on a review of foreign literature. Next, a quantitative survey was conducted to verify the assessments resulting from the theoretical analysis of the examined models. The studied group comprised municipalities with populations under 100,000 and the research covered the years 2010-2016. The study uses data from budget reports and consolidated balance sheets of local government units.
Źródło:
Optimum. Economic Studies; 2018, 3(93); 115-125
1506-7637
Pojawia się w:
Optimum. Economic Studies
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Quantitative and qualitative analysis of live sheep production from mass breeding system. Part II. Slaughter value of live sheep and the analysis of conditions of the functioning of the sheep breeding sector
Ilościowa i jakościowa analiza produkcji owczego żywca rzeźnego z chowu masowego. Cz.II. Wartość rzeźna żywca owczego i analiza uwarunkowań funkcjonowania sektora owczarskiego
Autorzy:
Liśkiewicz, M.J.
Gruszecki, T.M.
Greguła-Kania, M.
Powiązania:
https://bibliotekanauki.pl/articles/2196921.pdf
Data publikacji:
2013
Wydawca:
Uniwersytet Przyrodniczy w Lublinie. Wydawnictwo Uniwersytetu Przyrodniczego w Lublinie
Tematy:
quantitative analysis
qualitative analysis
sheep
lamb
animal production
breeding system
slaughter value
animal condition
animal breeding
SWOT analysis
Źródło:
Annales Universitatis Mariae Curie-Skłodowska. Sectio EE: Zootechnica; 2013, 31, 3; 18-26
0239-4243
2083-7399
Pojawia się w:
Annales Universitatis Mariae Curie-Skłodowska. Sectio EE: Zootechnica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Smart wireless sensor network and configuration of algorithms for condition monitoring applications
Autorzy:
Uhlmann, E.
Laghmouchi, A.
Geisert, C.
Hohwieler, E.
Powiązania:
https://bibliotekanauki.pl/articles/99644.pdf
Data publikacji:
2017
Wydawca:
Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Tematy:
condition monitoring
data analysis
sensor network
algorithm
MEMS sensor
cloud
Opis:
Due to high demand on availability of production systems, condition monitoring is increasingly important. In recent years, the technical development have improved for realization of condition monitoring applications as a result of technological progress in fields such as sensor technology, computer performance and communication technology. Especially, the approaches of Industrie 4.0 and the use of the Internet of Things (IoT) technologies offer high potential to implement condition monitoring solutions. The connection of several sensor data of components to the cloud allows the identification of anomalies or defect pattern, this information can be used for predictive maintenance and new data-driven business models in production industry. This paper illustrates a concept of a smart wireless sensor network for condition monitoring application based on simple electronic components such as the single-board computer Raspberry Pi 2 modules and MEMS (Micro-Electro-Mechanical Systems) vibration sensors and communication standards MQTT (Message Queue Telemetry Transport). The communication architecture used for decentralized data analysis using machine learning algorithms and connection to the cloud is explained. Furthermore, a procedure for rapid configuration of condition monitoring algorithms to classify the current condition of the component is demonstrated.
Źródło:
Journal of Machine Engineering; 2017, 17, 2; 45-55
1895-7595
2391-8071
Pojawia się w:
Journal of Machine Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Condition Monitoring of Rotating Machines: A Review
Autorzy:
Goyal, Deepam
Chaudhary, Anurag
Dang, Rajeev Kumar
Pabla, B. S.
Dhami, S. S.
Powiązania:
https://bibliotekanauki.pl/articles/1159447.pdf
Data publikacji:
2018
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Condition monitoring
fault detection
motor current signature analysis
wireless monitoring
Opis:
An uninterrupted health monitoring of machine is essential in various applications where failure of machine leads to loss of quality control, productivity and safety against catastrophic failure. Condition monitoring of machine involves continuous assessment on the performance of rotating components i.e. bearings, gears and motors and anticipating the faults before it cause any adversity. Rotating machines are commonly used in the industry for different applications such as railways, pumps, conveyors, blowers, elevator, mining industry, etc. Condition monitoring of rotating machines has been an important task for technicians, engineers, and researchers mainly to enhance structural reliability in a real time. This paper presents an enlarged survey on the expansion and the recent approaches in the condition monitoring of rotating machines. In current scenario, condition monitoring has proved their ability for fault detection of incipient faults in mechanical machines and equipments. Several techniques such as vibration monitoring, acoustic emission monitoring, invasive monitoring, oil monitoring are available for determining the health of rotating machines but all these monitoring methods needs expensive transducers and sensors.
Źródło:
World Scientific News; 2018, 113; 98-108
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Shape optimization for dynamic contact problems
Autorzy:
Myśliński, Andrzej
Powiązania:
https://bibliotekanauki.pl/articles/729249.pdf
Data publikacji:
2000
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
dynamic unilateral problem
shape optimization
sensitivity analysis
necessary optimality condition
Opis:
The paper deals with shape optimization of dynamic contact problem with Coulomb friction for viscoelastic bodies. The mass nonpenetrability condition is formulated in velocities. The friction coefficient is assumed to be bounded. Using material derivative method as well as the results concerning the regularity of solution to dynamic variational inequality the directional derivative of the cost functional is calculated and the necessary optimality condition is formulated.
Źródło:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization; 2000, 20, 1; 79-91
1509-9407
Pojawia się w:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fault diagnosis of rotating machines using vibration and bearing temperature measurements
Autorzy:
Nembhard, A. D.
Sinha, J. K.
Pinkerton, A. J.
Elbhbah, K.
Powiązania:
https://bibliotekanauki.pl/articles/328481.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
Tematy:
vibration monitoring
condition monitoring
rotating machinery
fault diagnosis
principal component analysis
Opis:
Acquisition and subsequent processing of vibration data for fault diagnosis of rotating machinery with multiple bearings, such as Turbo-generator (TG) sets, can be quite involved, as data are usually required in three mutually perpendicular directions for reliable diagnosis. Consequently, the task of diagnosing faults on such systems may be daunting for even an experienced analyst. Hence, the current study aims to develop a simplified fault diagnosis (FD) method that uses just a single vibration and a single temperature sensor on each bearing. Initial trials on an experimental rotating rig indicate that supplementing vibration data with temperature measurements gave improved FD when compared with FD using vibration data alone. Observations made from the initial trials are presented in this paper.
Źródło:
Diagnostyka; 2013, 14, 3; 45-51
1641-6414
2449-5220
Pojawia się w:
Diagnostyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Predicting motor oil condition using artificial neural networks and principal component analysis
Prognozowanie stanu oleju silnikowego za pomocą sztucznych sieci neuronowych i analizy składowych głównych
Autorzy:
Rodrigues, Joao
Costa, Ines
Farinha, J. Torres
Mendes, Mateus
Margalho, Luis
Powiązania:
https://bibliotekanauki.pl/articles/1841873.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
condition monitoring
oil analysis
multivariate analysis
predictive maintenance
monitorowanie stanu
analiza oleju
analiza wielowymiarowa
konserwacja predykcyjna
Opis:
The safety and performance of engines such as Diesel, gas or even wind turbines depends on the quality and condition of the lubricant oil. Assessment of engine oil condition is done based on more than twenty variables that have, individually, variations that depend on the engines’ behaviour, type and other factors. The present paper describes a model to automatically classify the oil condition, using Artificial Neural Networks and Principal Component Analysis. The study was done using data obtained from two passenger bus companies in a country of Southern Europe. The results show the importance of each variable monitored for determining the ideal time to change oil. In many cases, it may be possible to enlarge intervals between maintenance interventions, while in other cases the oil passed the ideal change point.
Bezpieczeństwo i wydajność silników takich, jak silniki Diesla czy gazowe, a nawet turbiny wiatrowe, zależą od jakości i stanu oleju smarowego. Stanu oleju silnikowego ocenia się na podstawie ponad dwudziestu zmiennych, z których każda ulega wahaniom w zależności od typu i zachowania silnika oraz innych czynników. W niniejszym artykule opisano model, który pozwala na automatyczną klasyfikację stanu oleju, z wykorzystaniem sztucznych sieci neuronowych i analizy składowych głównych. Badania przeprowadzono na podstawie danych uzyskanych od dwóch przewoźników pasażerskich działających na terenie jednego z krajów położonych na południu Europy. Wyniki pokazują, że każda z monitorowanych zmiennych ma znaczenie dla określenia idealnego czasu na wymianę oleju. Podczas gdy w wielu przypadkach w badanych przedsiębiorstwach możliwe było zwiększenie odstępów czasowych między działaniami konserwacyjnymi, w innych, idealny moment wymiany oleju został przekroczony.
Źródło:
Eksploatacja i Niezawodność; 2020, 22, 3; 440-448
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Time-frequency Representation -enhanced Transfer Learning for Tool Condition Monitoring during milling of Inconel 718
Autorzy:
Zhou, Yuqing
Sun, Wei
Ye, Canyang
Peng, Bihui
Fang, Xu
Lin, Canyu
Wang, Gonghai
Kumar, Anil
Sun, Weifang
Powiązania:
https://bibliotekanauki.pl/articles/24200823.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
tool condition monitoring
time-frequency analysis
Markov Transition Field
transfer learning
Opis:
Accurate tool condition monitoring (TCM) is important for the development and upgrading of the manufacturing industry. Recently, machine-learning (ML) models have been widely used in the field of TCM with many favorable results. Nevertheless, in the actual industrial scenario, only a few samples are available for model training due to the cost of experiments, which significantly affects the performance of ML models. A time-series dimension expansion and transfer learning (TL) method is developed to boost the performance of TCM for small samples. First, a time-frequency Markov transition field (TFMTF) is proposed to encode the cutting force signal in the cutting process to two-dimensional images. Then, a modified TL network is established to learn and classify tool conditions under small samples. The performance of the proposed TFMTF-TL method is demonstrated by the benchmark PHM 2010 TCM dataset. The results show the proposed method effectively obtains superior classification accuracies for small samples and outperforms other four benchmark methods.
Źródło:
Eksploatacja i Niezawodność; 2023, 25, 2; art. no. 165926
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Conditioning and error estimates in LQG design
Autorzy:
Petkov, P. Hr.
Konstantinov, M. M.
Christov, N. D.
Powiązania:
https://bibliotekanauki.pl/articles/971012.pdf
Data publikacji:
2008
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
LQG control
Riccati equations
perturbation analysis
condition numbers
forward error estimation
Opis:
Efficient conditioning and error estimates are presented for the numerical solution of matrix Riccati equations in the continuous-time and discrete-time LQG design. The estimates implemented involve the solution of triangular Lyapunov equations along with usage of the LAPACK norm estimator.
Źródło:
Control and Cybernetics; 2008, 37, 1; 85-87
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Morphological description of plant root status in the different-structured soils
Autorzy:
Slowinska-Jurkiewicz, A.
Domzal, H.
Pranagal, J.
Powiązania:
https://bibliotekanauki.pl/articles/25972.pdf
Data publikacji:
1998
Wydawca:
Polska Akademia Nauk. Instytut Agrofizyki PAN
Tematy:
biopore
soil structure
soil compaction
morphological analysis
life condition
root
plant
Źródło:
International Agrophysics; 1998, 12, 2
0236-8722
Pojawia się w:
International Agrophysics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Rip currents in the non-tidal surf zone with sandbars: numerical analysis versus field measurements
Autorzy:
Dudkowska, A.
Borun, A.
Malicki, J.
Schonhofer, J.
Gic-Grusza, G.
Powiązania:
https://bibliotekanauki.pl/articles/2079185.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
coastal zone
non-tidal surf zone
hydromorphological condition
bathymetry
hydroengineering
numerical analysis
Opis:
Rip currents, which are local seaward-directed jets with their mean velocity exceeding 0.5 m/s, have been a subject of many studies since the 1940s. They are an important part of the nearshore current system and in specific hydro- and litomorphological conditions can cause changes in the local bathymetry. Thus, a detailed analysis of the characteristics of this phenomenon is crucial both to public safety and hydroengineering. The main purpose of this research is to determine the wave conditions of a multi-bar non-tidal coastal zone environment in which rip currents can occur. In this study, we focus on a multi-bar non-tidal coastal zone environment located in the Southern Baltic Sea, where rip current driving forces are mostly reduced to the wind and wind-induced waves. This is one of very few comprehensive approaches to exploring the possibility of rip currents occurrence in such environmental conditions. During two field expeditions, there were carried out in situ measurements exploiting two GPS drifters. The results indicate the formation of irregular non-longshore flows (related to rip currents) in the studied area. To answer the question under what conditions the formation of rip currents takes place, an extended modelling experiment was performed. Deep-water wave conditions typical of the studied area were chosen due to bouy measurements. The total of 589 combinations of the significant wave height, the mean period and wave direction values were examined as test cases. The coastal flow in the area and tracks of virtual drifters were simulated by XBeach numerical model for all test cases. As a result, 589 nearshore currents fields were generated and two scenarios were indicated: a regular circulation (dominated by the longshore current) which is typical of this area (547 cases), and flows with rip current features (42 cases). This reflects the results of the field measurements carried out. It can be concluded that the wave direction is a dominating factor in the formation of rip currents. Namely the flows of this type may occur in the area of interest when the direction of a deep water wave is almost perpendicular to the shore. Such situations occur rarely. They cover about 7% of the days of the year. Thus, rip currents do not appear to be a significant factor in the reconstruction of the sea bottom in the studied area.
Źródło:
Oceanologia; 2020, 62, 3; 291-308
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Degradation-Threshold-Shock model for a system. The case of dependent causes of failure in finite-time
Autorzy:
Caballé, N. C.
Castro, I. T.
Powiązania:
https://bibliotekanauki.pl/articles/2069176.pdf
Data publikacji:
2016
Wydawca:
Uniwersytet Morski w Gdyni. Polskie Towarzystwo Bezpieczeństwa i Niezawodności
Tematy:
condition-based maintenance
degradation-threshold-shock models
finite-time analysis
gamma process
Opis:
This paper deals with a condition-based maintenance strategy (CBM) in finite-time horizon for a system subject to two different causes of failure, internal degradation and sudden shocks. Internal degradation is modelled under a gamma process and sudden shocks arrive at the system following a non-homogeneous Poisson process (NHPP). Both causes of failure are considered as dependent. When a sudden shock takes places, the system fails. In addition, the system is regarded to fail when the deterioration level reaches a critical threshold. Under this functioning scheme, a CBM strategy is developed for controlling the reliability of the system. Traditionally, this strategy is developed under an asymptotic approach. Hence, considering an infinite-time horizon is not always possible. In this paper, we analyse a CBM strategy under a finite-time horizon developing a recursive method which estimates the expected cost rate based on numerical integration and Monte Carlo simulation. A numerical example is provided in order to illustrate this complex maintenance model.
Źródło:
Journal of Polish Safety and Reliability Association; 2016, 7, 1; 13--20
2084-5316
Pojawia się w:
Journal of Polish Safety and Reliability Association
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evaluation of sensor-based condition monitoring methods as in-process tool wear and breakage indices - case study: drilling
Autorzy:
Tsanakas, J. A.
Botsaris, P. N.
Amirids, I. G.
Galeridis, G. G.
Powiązania:
https://bibliotekanauki.pl/articles/329544.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
Tematy:
tool condition monitoring
vibration signals
thermal signatures
spindle motor current
tool wear
statistical analysis
frequency domain analysis
Opis:
Today, effective unmanned machining operations and automated manufacturing are unthinkable without tool condition monitoring (TCM). Undoubtedly, the implementation of an adaptable, reliable TCM and its successful employment in industry, emerge as major instigations over the recent years. In this work, a sensor-based approach was deployed for the in-process monitoring and detection of tool wear and breakage in drilling. In particular, four widely reported indirect methods for tool wear monitoring, i.e. vibration signals together with thermal signatures, spindle motor and feed motor current measurements were obtained during numerous drillings, under fixed conditions. The acquired raw data was, then, processed both statistically and in the frequency domain, in order to distinguish the meaningful information. The study of the latter is influential in identifying the trend of specific signals toward tool wear mechanism. The efficiency of this information as a tool wear and/or breakage index is the feature that determines the effectiveness and reliability of a potential indirect TCM approach based on a multisensor integration. The paper concludes with a discussion of both advantages and limitations of this effort, stressing the necessity to develop simple, fast condition monitoring methods which are, generally, less likely to fail.
Źródło:
Diagnostyka; 2012, 2(62); 3-13
1641-6414
2449-5220
Pojawia się w:
Diagnostyka
Dostawca treści:
Biblioteka Nauki
Artykuł

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