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Wyświetlanie 16-30 z 86
Tytuł:
Performance Evaluation of a Zone-based Three-level Heterogeneous Clustering Protocol for WSNs
Autorzy:
Rao, Sanapala Shanmukha
Shilpi
Kumar, Arvind
Powiązania:
https://bibliotekanauki.pl/articles/24200745.pdf
Data publikacji:
2023
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
clustering
heterogeneous
network lifetime
stability period
zone-based WSN
Opis:
This paper proposes a zone-based three-level heterogeneous clustering protocol (ZB-TLHCP) for heterogeneous WSNs. In ZB-TLHCP, the sensor field/region is divided into zones where super, advance, and normal nodes are deployed uniformly and randomly. The performance of the proposed ZB-TLHCP system is compared with that of zonal-stable election protocol (Z-SEP), distributed energy efficient clustering (DEEC), and threshold-based DEEC (TDEEC) protocol by varying the number of super and advance nodes, their energy levels for the fixed sensor field, and the total number of nodes. Matlab simulation results revealed that the proposed ZB-TLHCP solution performed better than Z-SEP, DEEC, and TDEEC protocols, as it increased the instability period, prolonged the network's lifetime, and achieved higher throughput values.
Źródło:
Journal of Telecommunications and Information Technology; 2023, 3; 85--93
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A method for estimating the probability distribution of the lifetime for new technical equipment based on expert judgement
Autorzy:
Andrzejczak, Karol
Bukowski, Lech
Powiązania:
https://bibliotekanauki.pl/articles/2038033.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
uncertainty
expert elicitation of lifetime
quantile function
Weibull distribution
Opis:
Managing the exploitation of technical equipment under conditions of uncertainty requires the use of probabilistic prediction models in the form of probability distributions of the lifetime of these objects. The parameters of these distributions are estimated with the use of statistical methods based on historical data about actual realizations of the lifetime of examined objects. However, when completely new solutions are introduced into service, such data are not available and the only possible method for the initial assessment of the expected lifetime of technical objects is expert methods. The aim of the study is to present a method for estimating the probability distribution of the lifetime for new technical facilities based on expert assessments of three parameters characterizing the expected lifetime of these objects. The method is based on a subjective Bayesian approach to the problem of randomness and integrated with models of classical probability theory. Due to its wide application in the field of maintenance of machinery and technical equipment, a Weibull model is proposed, and its possible practical applications are shown. A new method of expert elicitation of probabilities for any continuous random variable is developed. A general procedure for the application of this method is proposed and the individual steps of its implementation are discussed, as well as the mathematical models necessary for the estimation of the parameters of the probability distribution are presented. A practical example of the application of the developed method on specific numerical values is also presented.
Źródło:
Eksploatacja i Niezawodność; 2021, 23, 4; 757-769
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hybrid reliability modelling under general uncertainty
Autorzy:
Guo, R.
Cui, Y.
Thiart, C.
Guo, D.
Powiązania:
https://bibliotekanauki.pl/articles/2069636.pdf
Data publikacji:
2010
Wydawca:
Uniwersytet Morski w Gdyni. Polskie Towarzystwo Bezpieczeństwa i Niezawodności
Tematy:
uncertain measure
hybrid lifetime
uncertain parameter
average chance reliability
Opis:
The real world phenomena are often facing the co-existence reality of different formality of uncertainty and thus the probabilistic reliability modeling practices are very doubtful. Under complicated uncertainty environments, hybrid variable modeling is important in reliability and risk analysis, which includes Bayesian distributional theory, random fuzzy distributional theory, as well as fuzzy random distributional theory as special distribution families. In this paper, we define a new hybrid lifetime which is specified by a random lifetime distribution with an uncertain distributed parameter, which is called as random uncertain hybrid lifetime. We furthermore define the average chance distribution as a quality index for quantifying the hybrid lifetime and accordingly the average chance reliability is derived.
Źródło:
Journal of Polish Safety and Reliability Association; 2010, 1, 1; 115--122
2084-5316
Pojawia się w:
Journal of Polish Safety and Reliability Association
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Technological solutions to extend the operating cycle of tools and industrial machinery
Autorzy:
Lukarski, Y.
Tashev, P.
Argirov, C.
Kondov, H.
Powiązania:
https://bibliotekanauki.pl/articles/391484.pdf
Data publikacji:
2017
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Odlewnictwa
Tematy:
operational lifetime
new materials
overlay welding
thermo-chemical treatment
Opis:
One of the most significant problems that engineers and researchers face is the development of technological solutions to extend the exploitation cycle of tools and industrial machinery. The research shows there are a few possibilities to solve this problem: 1. Development of new materials of enhanced working characteristics compared to those currently used. An example of this is the introduction of new metals and alloys in the automotive industry, the mining industry, etc. 2. Preventive processing of assemblies and parts prior to their use consisting mainly in overlay welding with wear resistant layers or thermo-chemical surface treatment of the parts. 3. Recovering assemblies and parts after their resource has been depleted. This is mainly applied in the mining industry, road construction, etc. Worn-out tools are overlay welded and reused. It has been proven that the price of the recovered details is 2 to 20 times lower than that of the new ones. Moreover, it should be pointed out that the recovery saves energy and ore resources and thus a significant environmental impact is achieved.
Źródło:
Prace Instytutu Odlewnictwa; 2017, 57, 4; 253-258
1899-2439
Pojawia się w:
Prace Instytutu Odlewnictwa
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Identification of heredity kernels and their influence on the life time of glass/polyester composites
Autorzy:
Olodo, E. T.
Adjovi, E. C.
Adanhounme, V.
Powiązania:
https://bibliotekanauki.pl/articles/955255.pdf
Data publikacji:
2014
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
lepkosprężystość
parametry sprężyste
kompozyty
heredity kernels
viscoelastic parameters
lifetime
Opis:
One of the major problems encountered in prediction of hereditary viscoelastic behavior of polymeric composites is the determination of heredity kernels. This issue comes down to identification of the model characterizing the viscoelastic properties of these materials. The purpose of this work is to propose a model for prediction of viscoelastic nonlinear behavior of laminate composite with polyester matrix, through the study and analysis of heredity kernels and their influence on the life time of this material. Identification of this model required experimental determination at room temperature, of viscoelastic parameters of heredity kernels by macroscopic approach. These data provide predictive tools for establishment of the life time and long term stress limit under static complex loading for this type of material.
Źródło:
International Journal of Applied Mechanics and Engineering; 2014, 19, 4; 725-734
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Gas turbine reliability model based on tangent hyperbolic reliability function
Autorzy:
Djeddi, A. Z.
Hafaifa, A.
Salam, A.
Powiązania:
https://bibliotekanauki.pl/articles/280120.pdf
Data publikacji:
2015
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
reliability estimation
reliability algorithms
lifetime distribution
Weibull distribution
availability
Opis:
The present work deals with the exploration of a new model proposed for the reliability analysis of industrial production systems. This proposed model is mainly based on the tangent hyperbolic function, where the survival function is determined and used in the lifetime distribution modeling taking into account of estimation the parameters of the proposed function. On the other side, tests validation is performed using the real data of a gas turbine installation. The obtained results allow the modeling of damage effects, hence the prediction of the performance of the examined gas turbine using the proposed model gives good results in terms of validity.
Źródło:
Journal of Theoretical and Applied Mechanics; 2015, 53, 3; 723-730
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research on preventive maintenance strategies and systems for in-service ship equipment
Autorzy:
Song, Tingxin
Tan, Taiyang
Han, Guochen
Powiązania:
https://bibliotekanauki.pl/articles/32887248.pdf
Data publikacji:
2022
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
preventive maintenance
FMEA
lifetime prediction
decision system
ship equipment
Opis:
With continuous improvements in the function and performance of ship equipment, mechanisms of failure have become more and more complicated. To avoid over-maintenance or under-maintenance in existing routine ship maintenance strategies, a ship-level method for repair decisions based on the preventive maintenance concept is proposed in this paper. First, the anticipated repair demand levels of key components are calculated using an improved failure mode and effects analysis (FMEA) method; second, a Weibull distribution model is established, and the parameters are estimated using the maximum likelihood estimation (MLE) to predict the characteristic life of the equipment; then, logical decision principles and rule-based reasoning (RBR) are used to determine the ship repair level and repair timing. Finally, the feasibility and application value of the proposed repair strategy were verified by case studies, and a ship-level system for repair decisions was established.
Źródło:
Polish Maritime Research; 2022, 1; 85-96
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Scheduling Based Wireless Sensor Networks Integrated with IoT Environment
Autorzy:
Mahendran, N.
Powiązania:
https://bibliotekanauki.pl/articles/1193556.pdf
Data publikacji:
2016
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Data Scheduling Schemes
Energy Efficient
IoT
Network lifetime
Sensor Network
Opis:
Wireless Sensor networks are widely adopt in military, target tracking, signal processing and monitoring applications like traffic and structural, the small and low cost unreliable sensor nodes in these applications uses batteries as the sole energy source. The energy efficiency becomes difficult task as the tiny and less weight battery act as source of each node. Scheduling the different category of data packets is a way to reduce the power consumption and increasing the lifetime of sensor nodes. The existing scheduling algorithms are not adapted to the environment changes. The basic FCFS (First Come First Serve) suffered by long delay while transmit the real time data packets. In DMP (Dynamic Multilevel Priority) real time data packets occupies highest priority, the remaining non real time data packets sent to lower priority level queues. Some real time task holds the resources for longer time, the other task have to wait, it makes the deadlock condition. The NJN (Nearest Job Next) will select the nearest requesting sensor node for service, real time packets have to wait long time. The proposed Adaptive weighted scheduling scheme changes the behavior of the network queue by adaptively changes the weights based on network traffic. Simulation results proof that, adaptive weighted scheduling algorithm works better than the FCFS and DMP data scheduling in terms of energy consumption and lifetime. Our future scheme to integrate Internet of Things (IoT) with the WSN to increase the performance of the wireless networks.
Źródło:
World Scientific News; 2016, 41; 116-127
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
EEULA: an energy-aware event-driven unicast algorithm for wireless sensor network by learning automata
Autorzy:
Kashani, A. A. S.
Noori, A. M. M.
Powiązania:
https://bibliotekanauki.pl/articles/102180.pdf
Data publikacji:
2016
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
network lifetime
wireless sensor network
learning automata
energy efficiency algorithm
Opis:
Energy consumption is one of the major challenges in wireless sensor networks, thus necessitating an approach for its minimization and for load balancing data. The network lifetime ends with the death of one of its nodes, which, in turn, causes energy depletion in and partition of the network. Furthermore, the total energy consumption of nodes depends on their location; that is, because of the loaded data, energy discharge in the nodes close to the base station occurs faster than other nodes, the model presented here, through using learning automata, selects the path appropriate for data transferring; the selected path is rewarded or penalized taking the reaction of surrounding paths into account. We have used learning automata for energy management in finding the path; the routing protocol was simulated by NS2 simulator; the lifetime, energy consumption and balance in an event-driven network in our proposed method were compared with other algorithms.
Źródło:
Advances in Science and Technology. Research Journal; 2016, 10, 30; 9-18
2299-8624
Pojawia się w:
Advances in Science and Technology. Research Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Estimation of high temperature fatigue lifetime of SUS304 steel with an energy parameter in the critical plane
Ocena wysokotemperaturowej trwałości zmęczeniowej stali SUS304 za pomocą parametru energetycznego w płaszczyźnie krytycznej
Autorzy:
Łagoda, T.
Macha, E.
Sakane, M.
Powiązania:
https://bibliotekanauki.pl/articles/281113.pdf
Data publikacji:
2003
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
low-cycle fatigue
multiaxial fatigue
energy approach
lifetime
high temperature
Opis:
The paper studies the application of the energy parameter, a sum of elastic and plastic strain energy densities in the critical plane, for the correlation of two series of proportional biaxial low-cycle lives using SUS304 stainless steel at elevated temperature. The first data used thin-walled cylinder specimens subjected to 7 proportional strain paths of combined tension-torsion and the other used cruciform specimens subjected to 5 proportional strain paths of biaxial tension-compression. These tests were done at the temperature of 923 K. The normal total strain energy density in the plane with the maximum damage was a suitable parameter for describing the test results.
Praca dotyczy zastosowania parametru energetycznego, sumy gęstości energii sprężystej i plastycznej odkształcenia w płaszczyźnie krytycznej do korelacji dwóch serii proporcjonalnych, dwuosiowych, niskocyklowych trwałości zmęczeniowych stali nierdzewnej SUS303 w podwyższonej temperaturze.Badano cienkościenne próbki cylindryczne poddane siedmiu proporcjonalnym torom odkształcenia w warunkach kombinacji rozciągania-skręcania oraz próbki krzyżowe poddane pięciu proporcjonalnym torom odkształcenia w warunkach dwuosiowego rozciągania-ściskania. Badania prowadzono w temperaturze 923 K. Gęstość energii całkowitego odkształcenia normalnego w płaszczyźnie maksymalnego uszkodzenia była odpowiednim parametrem do opisania wyników badań.
Źródło:
Journal of Theoretical and Applied Mechanics; 2003, 41, 1; 55-73
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Steady and transient thermal state of turbine disc estimation for life time monitoring
Stałe i przejściowe oszacowanie stanu termicznego tarczy turbiny w celu monitorowania jej żywotności
Autorzy:
Martseniuk, Yevhen
Powiązania:
https://bibliotekanauki.pl/articles/36416847.pdf
Data publikacji:
2020
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Lotnictwa
Tematy:
lifetime
monitoring
thermal-stress state
model
żywotność
stan naprężenia termicznego
Opis:
In connection with increasing intensification of the working process in a gas turbine engine and increasing requirements for economy, the problem of defining and monitoring the main parts lifetime is becoming more vital. Modern algorithms of the monitoring systems are based on taking into account the levels of part temperature and total equivalent stress throughout the flight cycle. Thermal and stressstrain states of the critical zones of the main parts are determined on the basis of information received from the sensors installed in the engine gas path. Turbine disks are located in the internal cavities of the engine and are cooled by air from the compressor. However, in some designs, the disk cavity can be separated from the place of cooling air bleed by several stages of non-contact labyrinth seals, which will lead to some delay in changing the parameters of the cooling air flow when changing the engine operating mode. It has been observed that if this situation is not taken into account, it can lead to significant errors (more than 40%) in determining the lifetime for the peripheral zone of the disk. At the same time, this error is minimal for the hub and the middle zone of the disk, and the existing monitoring algorithms can be used.
W związku z coraz większą intensyfikacją procesu pracy w silniku turbiny gazowej i rosnącymi wymaganiami ekonomicznymi, coraz bardziej zaostrza się problem definiowania i monitorowania żywotności głównych części. Nowoczesne algorytmy systemów monitorowania opierają się na uwzględnianiu poziomów temperatury części i całkowitego równoważnego obciążenia w całym cyklu lotu. Stany termiczne i naprężeniowo-odkształceniowe stref krytycznych części głównych określane są na podstawie informacji otrzymywanych z czujników zainstalowanych w torze gazowym silnika. Tarcze turbinowe umieszczone są w wewnętrznych wnękach silnika i są chłodzone powietrzem ze sprężarki. Jednak w niektórych konstrukcjach wnęka tarczowa może być oddzielona od miejsca upustu powietrza chłodzącego kilkoma stopniami bezdotykowych uszczelnień labiryntowych, co spowoduje pewne opóźnienie zmiany parametrów przepływu powietrza chłodzącego przy zmianie trybu pracy silnika. Wykazano, że jeśli sytuacja ta nie będzie brana pod uwagę, może to prowadzić do znacznych błędów (ponad 40%) w określeniu okresu eksploatacji dla strefy peryferyjnej tarczy. Jednocześnie błąd ten jest minimalny dla koncentratora i strefy środkowej dysku, a istniejące algorytmy monitorujące mogą być stosowane.
Źródło:
Transactions on Aerospace Research; 2020, 3 (260); 21-29
0509-6669
2545-2835
Pojawia się w:
Transactions on Aerospace Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimal credit period and ordering quantity for credit dependent trended demand and deteriorating items with maximum lifetime
Autorzy:
Shah, N. H.
Shah, D. B.
Patel, D. G.
Powiązania:
https://bibliotekanauki.pl/articles/970075.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
inventory
trended demand
trade credit
default risk
deterioration
maximum lifetime
Opis:
In this paper, an inventory system is analyzed regarding a trended demand. The seller offers its buyer a credit period for settling the account, which attracts more buyers and enhances market demand. However, the offer of credit period leads to default risk for the supplier. The units in inventory are deteriorating continuously and also have definite maximum lifetime. The aim is to maximize the profit of the retailer. Numerical examples are given to validate the developed mathematical model. Sensitivity analysis is performed to obtain the critical inventory parameters and deduce the managerial strategies.
Źródło:
Control and Cybernetics; 2015, 44, 2; 311-320
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Lifetime distributions with wave-like bathtub hazard
Autorzy:
Guo, R.
Thiart, C.
Cui, Y.
Guo, D.
Powiązania:
https://bibliotekanauki.pl/articles/2069543.pdf
Data publikacji:
2011
Wydawca:
Uniwersytet Morski w Gdyni. Polskie Towarzystwo Bezpieczeństwa i Niezawodności
Tematy:
lifetime distribution
hazard
bathtub hazard
likelihood function
maximum likelihood estimation
Opis:
In this paper, we argue the necessity of dealing with lifetime distributions with wave-like bathtub hazard function. Four classes of wave-like bathtub hazards are investigated. For preparing maximum likelihood estimation of the hazard parameters, the first-order and second-order partial derivatives are derived.
Źródło:
Journal of Polish Safety and Reliability Association; 2011, 2, 1; 115--122
2084-5316
Pojawia się w:
Journal of Polish Safety and Reliability Association
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Weibull lifetime model with randomised failure-free time
Autorzy:
Sulewski, Piotr
Szymkowiak, Magdalena
Powiązania:
https://bibliotekanauki.pl/articles/2156948.pdf
Data publikacji:
2022-12-15
Wydawca:
Główny Urząd Statystyczny
Tematy:
Weibull lifetime model
randomised failure-free time
compound Weibull distributions
Opis:
The paper shows that treating failure-free time in the three-parameter Weibull distribution not a constant, but as a random variable makes the resulting distribution much more flexible at the expense of only one additional parameter.
Źródło:
Statistics in Transition new series; 2022, 23, 4; 59-76
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimization of critical infrastructure operation and safety with considering climate-weather change influence : maximizing safety lifetime
Autorzy:
Kołowrocki, K.
Kuligowska, E.
Soszyńska-Budny, J.
Powiązania:
https://bibliotekanauki.pl/articles/2068785.pdf
Data publikacji:
2018
Wydawca:
Uniwersytet Morski w Gdyni. Polskie Towarzystwo Bezpieczeństwa i Niezawodności
Tematy:
critical infrastructure
safety
operation process
climate-weather change
optimization
safety lifetime
Opis:
The method based on the results of the joint model linking a semi-Markov modelling of the critical infrastructure operation process with a multistate approach to critical infrastructure safety and linear programming are proposed to the critical infrastructure operation and safety optimization. This method determining the optimal values of limit transient probabilities at the critical infrastructure operation states that maximize the critical infrastructure safety lifetime in the safety state subsets is proposed.
Źródło:
Journal of Polish Safety and Reliability Association; 2018, 9, 1; 1--10
2084-5316
Pojawia się w:
Journal of Polish Safety and Reliability Association
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 16-30 z 86

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