Perform Reliability Analysis Research Articles

Prediction Model of Magnetorheological (MR) Fluid Damper Hysteresis Loop using Extreme Learning Machine Algorithm

Abstract Magnetorheological (MR) fluid is among the smart materials that can change its default properties with the influence of a magnetic field. Typical application of an MR fluid based device involves an adjustable damper which is commercially known as an MR fluid damper. It is used in vibration control as an isolator in vehicles and civil engineering applications. As part of the device development process, proper understanding of the device properties is essential for reliable device performance analysis. This study introduce an accurate and fast prediction model to analyse the dynamic characteristics of the MR fluid damper. This study proposes a new modelling technique called Extreme Learning Machine (ELM) to predict the dynamic behaviour of an MR fluid damper hysteresis loop. This technique was adopted to overcome the limitations of the existing models using Artificial Neural Networks (ANNs). The results indicate that the ELM is extremely faster than ANN, with the capability to produce high accuracy prediction performance. Here, the hysteresis loop, which represents the relationship of force-displacement for the MR fluid damper, was modelled and compared using three different activation functions, namely, sine, sigmoid and hard limit. Based on the results, it was found that the prediction performance of ELM model using the sigmoid activation functions produced highest accuracy, and the lowest Root Mean Square Error (RMSE).

Adoption of a Bayesian Network for the Operational Reliability Analysis of Aircraft Systems

To assess and analyze the operational reliability of aircraft systems, an aircraft system Bayesian network (ASBN) method is proposed with the functional and logical coupling relationship of aircraft components, which integrates the characteristics of components related to aircraft operation, is built for analyzing the operational reliability under considering the effect of stochastic features. The aircraft system operating reliability is first assessed by forward inference of ASBN. And the most likely failure component or subsystem under the appearance of different failure condition severity categories are identified. The results show that the aircraft system operating reliability is not as high as the reliability of its components; the most likely failure component or subsystem are those tightly connected to other components or subsystems. The efforts of this paper provide a useful way for deriving operational reliability analysis of complex systems.

전시참가기업의 내부특성이 전시회 참가성과 및 시장성과에 미치는 영향

This study examines not only Exhibitor’s internal characteristics but also effects of Trade Show participation performance on market performance. Theoretical study on literature review and empirical study on Trade Show participation of Exhibitor were observed in this study in order to achieve a goal, In addition, this study is to define internal characteristics of Exhibitor, Trade Show participation performance and market performance and implement factor derivation through literature review. With verification of reliability and validity, this study performed reliability analysis and factor analysis. Regression analysis was used in order to analyze relationship among internal characteristics of Exhibitor, Trade Show participation performance and market performance. As a result, 1)sale's scale of the Trade Show participation performance's structural characteristics affects sale's performance, and both sale's scale and a number of employee affect communication performance. 2)Overseas market experience and previous business experience with buyer of Trade Show participation Exhibitor's knowledge traits analyzed as statistically significant to the communication performance acquisition. 3) the Trade Show participation performance and the market performance of regression analysis showed that the sales performance and communication performance had both statistically significant impact on overseas and domestic market performance. 4)Trade Show participation performance and market performance's longitudinal research analysis result showed that both sale's performance and market performance had statistically significant effect on domestic market performance, however, the significance gradually decreases. 5)communication performance in influencing relationship of overseas market performance had the greatest impact between 6~12months after the exhibition terminated, but gradually decreased and dissipated. sale's performance had no influence within 12months after the exhibition ended, however, sale's performance had influence between 12~18months after Trade Show.

Patient-reported outcomes of ductoscopy procedures for pathologic nipple discharge

BackgroundPathologic nipple discharge (PND) is a common complaint often associated with breast cancer. However, when ultrasound and mammography are negative, the chances of malignancy are lower than 5%. Currently, major duct excision and microdochectomy are often recommended to alleviate symptoms and definitely rule out malignancy, but can cause infections and breastfeeding problems. Ductoscopy is a minimally invasive endoscopy technique that allows visualization of the mammary ducts and may not only obviate surgery but also detect malignancy. The aim of this study was to determine quality of life (QOL) after ductoscopy in patients with PND.Materials and methodsAll PND patients referred for ductoscopy between 2014 and 2015 to our hospital were included. Ductoscopy procedures were performed under local anaesthesia in the outpatient clinic. Patients were asked to fill out questionnaires (Breast-Q, EQ-5D-5L and SF-36) on the day of ductoscopy, and after 2 weeks, 3 and 6 months. Additionally, we performed reliability analysis to determine if these questionnaires were suitable for PND patients.ResultsFifty consecutive patients underwent ductoscopy of whom 47 patients participated in this study. One domain of SF-36 (vitality) varied significantly over time. Breast-Q, SF-36 and EQ-5D-5L showed that QOL after ductoscopy for PND was unaffected by ductoscopy. Success of the ductoscopy procedure was a significant predictor for satisfaction with the result domain.ConclusionDuctoscopy is a minimally invasive technique that does not seem to impact QoL of PND patients over time. Breast-Q, SF-36 and EQ-5D-5L seem to be suitable existing QOL tests for PND patients undergoing ductoscopy, whereas SF-36 would require modifications.

Mathematical modeling of the influence of defects in structures of an on-farm network of rice systems on their operational reliability

This article presents the results of mathematical modeling of the effects of defects in the structures of an on-farm network of rice systems over a long period of work on their operational reliability. This year marks the ninety years since the first rice system was built in 1929 in the Kuban. In the Krasnodar Territory, rice systems have been used that have been in continuous operation for more than thirty years. Therefore, it is necessary to scientifically substantiate the costs of maintenance and overhaul, and a numerical experiment was carried out on various defects in the structures of the on-farm network of rice systems. Based on field studies, mathematical modeling was performed for the most common defects by the ground- penetrating radar (GPR) sounding—a transverse crack crossing the drainage structure, as well as the destruction of the sides of the well. All calculations were performed on the SCAD Office calculation complex. In the course of mathematical modeling, it was found that the drainage pipeline with a well has a margin of operational reliability, which decreases over the years of use of the structure. In the formulation of mathematical modeling of a model of a drainage structure with a well without defects and damages, the aim was to establish the adequacy of the solid-state model of the stress-strain state at maximum water pressure with existing field tests under various boundary conditions. According to the data of the technical analysis of operational reliability, the operational reliability of the structures of the on-farm network of rice systems is determined and characterized. Provision of the operational reliability of rice systems is to carry out engineering, technical and land reclamation measures for sustainable and effective water conservation, rational use and development of the water management complex as a whole.

Performance Tuning and Reliability Analysis of the Electrostatically Configured Nanotube Tunnel FET with Impact of Interface Trap Charges

This paper examines, an electrostatically configured Nano-Tube Tunnel Field-Effect Transistor (ED-NTTFET). During the fabrication process, different charges such as fixed charge, oxide trapped charge, and interface trapped charge have been produced at the gate oxide interface. So the effect of positive and negative interface trapped charge (+ITC & -ITC) has been proposed for the first time for electrostatic doped-based Nano-Tube TFET (ED-NTTFET). There are two types of techniques, charge plasma (EP) based technique and electrostatic doped (ED) technique is used to produce the induced charge in the intrinsic channel region. In the charged plasma (CP) technique, the metal work-function is used to produce the induced charge while in the electrostatic doped (ED) technique electrostatic voltage is applied across the source and drain side to produce the induced charge in the intrinsic channel region. Analysis of the various device parameters such as hole/electron concentration, energy diagram, electric field, tunneling rate, driving current, OFF current, ON current, ION/IOFF, threshold voltage, and average sub-threshold slope in the presence of interface trapped charge (ITC). Due to positive interface trapped charge electric field and band to band tunneling rates are improved. So the drain current of the device also improved from the 2.94*10−5 A/um2 to 5.35*10−5A/um2. Linearity parameters such as second & third order trans-conductance (gm2 & gm3), second & third order voltage intercept point (VIP2 & VIP3), second & third order harmonics distortions (HD2 & HD3) and intermodulation distortions (IMD) have been discussed. The negative interface trapped charge (-ITC) degrades the linearity parameter of the device and the positive interface trapped charge (+ITC) improves the linearity parameter of the device. The proposed electrostatic doped nano-tube TFET (ED-NTTFET) produced higher cut-off frequency at lowers operating gate voltage.

Risk-Based Decision Making Method for Selecting Slope Stabilization System in an Abandoned Open-Pit Mine

Background:The construction and stabilization of deep excavations are associated with several uncertainties due to heterogeneous geological conditions. Therefore, the conventional methods of slope stability analysis do not provide reasonable results.Aim:Hence, it is logical to perform reliability analysis and also risk assessment to make a wiser decision under uncertainty for choosing the proper stabilization method of slopes.Methods:In this regard, a real case study, a 50-meter-deep abandoned open-pit mine, is considered. In the past, the studied deep excavation was located in a rural area, away from the important structures. However, due to the development of the city, the open-pit mine is now located in the city. Furthermore, the Kan River is located on the eastern side of the excavation. Deterministic analysis showed that that Factor of Safety is not sufficient for permanent condition; thus, the deep excavation may have destructive impacts on the adjacent structures and infrastructures by putting them in danger in the case of failure.Results:These circumstances resulted in using reliability analysis and risk assessment using non-deterministic approach. Random Set Finite Element Method (RS-FEM), a non-probabilistic method, is used in determining how much the slope is reliable. The upper and lower bounds of probability of excessive displacement and probability of failure are obtained using RS-FEM by Plaxis2D software. Afterward, HAZUS is successfully used to quantify the economic risk of different stabilization alternatives by defining various scenarios in order to consider the consequences of excavation failure on adjacent utilities and infrastructures.Conclusion:The best alternative is defined as the stabilization method with the lowest economic risk. As a result, it is noticeable that this paper provides a comprehensive methodology for decision making, based on reliability analysis and risk assessment, in stabilizing slopes.

DETERMINATION OF THE TREND OF CHANGES OF RELIABILITY INDICATORS OF STATE AVIATION HELICOPTERS ACCORDING TO OPERATING DATA

The most important characteristics of the processes efficiency in aircraft equipment technical operation are the operational reliability characteristics. High reliability of aviation equipment is the main condition for its readiness, efficiency and safety.
 The aircraft equipment reliability is its ability to perform specified functions, maintaining during some time the values of the established flight and technical and operational indicators within the specified limits, which correspond to the specified modes and conditions of use, maintenance, repair, storage and transportation.
 Despite the quick scientific and technological progress in aviation, the problem of flights safety has become extremely acute in the present time. Empirical data statistical processing is an urgent task in monitoring of the Ukrainian Armed Forces aircrafts operation and determining trends in maintenance and repair, areas of modernization of armaments and military equipment.
 The subject of the work is the analysis and system approach based on the developed estimation technique of aviation equipment reliability indicators. The results of determined helicopters and their functional systems reliability are presented. The trend and the main reasons for the change in reliability indicators for 2016-2019 are determined.
 The main purpose of reliability analysis is to determine the causal relationships between quantitative and qualitative reliability indicators and the level of flight safety that lead to aviation accidents.
 Statistical information in the form of fault records and reports, where the generalized operational data are sent by the State aviation units according to the methodical recommendations.
 Indicators analysis of operational reliability and flights safety for helicopters according to statistical data of failures, damages and incidents is done. Moreover, the trend and the main reasons for the helicopters reliability indicators changes for the period 2016-2019 are defined.
 The results of research are presented in the final tables, which show the average values of operational reliability, flight safety and the level of combat flight task for different types of helicopters in all specialties.
 The causes of malfunctions that affect the level of operational reliability, flight safety and non-fulfillment of the flight task on helicopters for the period 2015-2019 were taken into account.
 According to the statistics analysis of the malfunctions reported causes , it is determined that the total number of reported malfunctions on different types of helicopters in 2019 increased by 11.0% compared to 2018, compared to 2017 by 43.7%, compared to 2016 by 58.4%, compared to 2015 by 70.0%.

Active learning relevant vector machine for reliability analysis

In this study, an adaptive relevant vector machine, which is developed within a probabilistic Bayesian learning framework, is combined with Monte Carlo simulation (MCS) to perform reliability analysis with high efficiency and accuracy. A new active learning function is proposed that comprehensively considers the probability of mis-predictions and spatial locations of the existing sampling points to search for the best next point to enrich the training samples. To avoid redundant original model evaluations, an efficient stopping criterion is adopted to terminate the active learning process in a timely manner. The proposed method is tested with five examples involving non-differentiability, high non-linearity, and practical engineering problems. The proposed method can obtain highly accurate failure probability predictions with a small number of evaluations of the original model in comparison with the direct MCS and other methods in the literature. In conclusion, the proposed method is recommended for structural reliability analyses in engineering practice.

Modeling Spatial Variance and Investigating the Effects of Variability on Intact Rock Strength and Stability of Entries in a Longwall Mine

Spatial variance of rock properties is an important characteristic of rock which addresses the heterogeneity of mechanical and physical properties and their effect on underground mining. Assessing spatial variance can be useful for both locating potential difficult grounds and performing reliability analysis in the mining support system. This study shows a microscale numerical model for rock material based on continuum mechanics. To consider the spatial correlation factor of mechanical properties in realistic rock mass, this study introduces a spatial correlation concept into the traditional type III extreme value distribution model. Based on the improved microscale random model, we conducted a series of numerical uniaxial compressive tests and one longwall mine model to investigate the progressive failure of rock. The results show that spatial correlation factor can significantly affect the load-deformation curves and fracture patterns. The spatial variance model was applied to a longwall mine that included several cutting sequences to observe the influence of the spatial variance on roof behavior. The cohesion and friction random fields induced failure that propagated randomly through the immediate roof in different entries. The results showed that the spatial variance provides an accurate prediction of erratic roof falls in coal mines.

Reliability Analysis of Distribution Network Operation Based On Short-Term Future Big Data Technology

This paper firstly establishes a four-dimensional index system for distribution network operation reliability. Using principal component analysis method, it extracts the main evaluation indicators from a large amount of data, and analyzes the influencing factors of the indicators according to the main evaluation indicators. According to the parallel association rules The method establishes the relevant model, and extracts the main indicators of operational reliability and the strong correlation rules between each influencing factors, so as to obtain the main influencing factors. The artificial neural network is proposed to predict, based on historical data and real-time data. The main influencing factors are used as the input and output of the forecast, and the output is expressed by the main evaluation index, and the operational reliability index for a period of time is judged. The calculation of the proposed strategy can quickly and effectively predict the operational reliability of the distribution network.

Software Reliability Prediction and Estimation

The rapid growth of the software products tends to increase the software application complexity. The complexity affects the software quality which is achieved by means of software reliability. It is desirable to perform reliability analysis at the early phase of Software Development Life Cycle. The paper conducts a thorough analysis on Bayesian model and Markov model which are common for both reliability prediction and estimation. We evaluate the state based model and path based model for reliability assessment and results obtained in both are same.

Mapping the energy usage in Brazilian public schools

Understanding the actual conditions in school buildings regarding energy usage and environmental satisfaction gives way to the development of consistent building stock modelling. In the Brazilian context, a deep-rooted inefficient structure of energy management implies a lack of mapping the actual conditions of the public schools. Therefore, this paper aimed to assess the actual energy performance of school buildings in Brazil. This paper innovates by integrating questionnaire responses and billed energy data to allow the construction of an evidence-based stock model through a statistical approach, which was never performed for the Brazilian building stock. Moreover, the association of energy use intensity (EUI) with the core aspects of building characteristics, occupancy, environmental satisfaction and necessary improvements mapped the relevance of such aspects in energy usage patterns. Additionally, a discussion of the EUI indicators was addressed. Results showed an unprecedented broad panorama of the school building stock in Brazil and its main features. In terms of statistical analysis, the Weibull distribution was appropriate for representing the continuous variables of the stock. The EUI as a function of the number of students was more suitable than the floor-plan area to achieve a reliable energy performance analysis. Several tests were performed to assess if the energy management, environmental satisfaction and maintenance practices impacted the EUI or not. Finally, the main conclusion was that the stock model obtained was simple and fit the energy management structure in the Brazilian scenario.

Efficient reliability analysis of earth dam slope stability using extreme gradient boosting method

Reliability analysis approach provides a rational means to quantitatively evaluate the safety of geotechnical structures from a probabilistic perspective. However, it suffers from a known criticism of extensive computational requirements and poor efficiency, which hinders its application in the reliability analysis of earth dam slope stability. Until now, the effects of spatially variable soil properties on the earth dam slope reliability remain unclear. This calls for a novel method to perform reliability analysis of earth dam slope stability accounting for the spatial variability of soil properties. This paper develops an efficient extreme gradient boosting (XGBoost)-based reliability analysis approach for evaluating the earth dam slope failure probability. With the aid of the proposed approach, the failure probability of earth dam slope can be evaluated rationally and efficiently. The proposed approach is illustrated using a practical case adapted from Ashigong earth dam. Results show that the XGBoost-based reliability analysis approach is able to predict the earth dam slope failure probability with reasonable accuracy and efficiency. The coefficient of variations and scale of fluctuations of soil properties affect the earth dam slope failure probability significantly. Moreover, the earth dam slope failure probability is highly dependent on the selection of auto-correlation function (ACF), and the widely used single exponential ACF tends to provide an unconservative estimate in this study.

Introduction of S5000F Specification and Its Application on Operational Reliability Analysis and Feedback of Civil Aircraft

Introduction of S5000F Specification and Its Application on Operational Reliability Analysis and Feedback of Civil Aircraft

On the reliability of structures equipped with a class of friction-based devices under stochastic excitation

This work presents a general framework for performing reliability analyses of involved structural models equipped with friction-based devices under stochastic excitation. An experimentally validated model that takes into account main sources of performance degradation that these devices experience during seismic events is considered. To deal with the variability of future excitations, a stochastic excitation model is adopted in the present formulation. First excursion probabilities are used as measures of system reliability. The associated reliability analysis is carried out by combining an advanced simulation technique with an adaptive parametric meta-model. The proposed framework is suitable for direct implementation in realistic applications. The effectiveness of the methodology is demonstrated by means of two application problems involving relatively large finite element models.

Reliability assessment of RC frames rehabilitated by eccentrically braces having vertical shear link

A considerable number of existing reinforced concrete (RC) structures need to seismic rehabilitation due to several reasons such as being designed just based on gravity loading and/or having an unsatisfactory level of ductility. One of the types of steel bracing can be referred to eccentrically braced frames with a vertical link. This system has some advantages such as an increase in ductility, stiffness and lateral strength, the ability to adapt to the architecture, and also the minimum weight added to the structure. In this study, reliability analysis assessment of two existing 3-, and 9-story RC frames in two cases including original and rehabilitated with an eccentrically braced frame having a vertical link is presented. Two limit states are defined as: maximum roof displacement and maximum inter-story displacement. The seismic behavior of frames was assessed by nonlinear static pushover analysis with finite element program OpenSees in two performance levels, including collapse prevention and life safety. Five random variables represented the variability in resistance of concrete material, bars and steel profiles yield stress, beams height, columns dimension, and also bars cross-section. Sensitivity analysis was carried out to recognize the effect of random variables on the reliability index. The reliability analysis was performed by two different methods: Hasofer–Lind and Monte Carlo with 25, 100, 1000, 10,000 and 100,000 simulated samples by considering two distributions including Normal and Log-Normal. Finally, a comparison between two common reliability methods was carried out in order to select the most appropriate method for performing the best seismic performance reliability analysis of RC frames rehabilitated by the proposed system.

Reliability Analysis of Large Span Cable-stayed Bridges Based on Support Vector Machine

a method of combining the support vector machine and the intelligent algorithm to perform reliability analysis on large span cable-stayed bridges was proposed in this paper. The algorithm is verified by an example, which shows that the algorithm has higher precision and can be extended to the actual project. Therefore, this paper takes Jiangmen North Street Waterway Bridge as the engineering background, uses the finite element software ANSYS to establish the cable-stayed bridge model and MATLAB software to compile the intelligent algorithm and data processing. It mainly analyzes the reliability of the main beam mid-span deflection, the cable stress and main tower stress of the North Street Waterway Bridge. Finally, the general limit range method is used to estimate the reliability index of the North Street waterway bridge structure system. The results show that the cable stay failure has the greatest impact on the reliability of the entire structural system, so it is necessary to pay attention to the maintenance and monitoring of stay cables.

Performance Margin Modeling and Reliability Analysis for Harmonic Reducer Considering Multi-Source Uncertainties and Wear

The harmonic reducer of the space drive mechanism is one of the critical components of the satellite remote sensing system and its reliability is always required strictly in practice. During the manufacturing and usage processes of the harmonic reducer, uncertainties are ubiquitous and performance degradation is inevitable, which is mainly caused by the wear between the meshed tooth surfaces. They influence the reliability of harmonic reducer. In this paper, a performance margin modeling and reliability analysis for harmonic reducer considering multi-source uncertainties and wear is proposed. Firstly, based on the functional principle and the influence of wear, the performance margin model is established using hysteresis and transmission errors as key performance parameters. Then multi-source uncertainties are analyzed and quantified, including manufacturing errors, uncertainties in operational and environmental conditions, and uncertainties in performance thresholds. Finally, the reliability model is constructed based on the performance margin. A case study of a harmonic reducer is applied and the reliability sensitivity analysis is implemented to show the practicability of the proposed method. The results show that the proposed method can provide some suggestions to the design and manufacturing phases of the harmonic reducer.

Experimental Study and Reliability Analysis of Flexural Capacity of RC Beams Reinforced with 600 MPa Grade Steel

Flexural capacity of beams reinforced with 400 or 500 MPa grade steel can be accurately estimated by using equations provided in design codes. Recently, 600 MPa grade steel has evolved in the construction industry, and the applicability of existing equations for this grade of steel should be verified by performing experimental investigation. By conducting tests on concrete beams reinforced with 600 MPa grade high‐strength steel, this study investigates the flexural performance for different concrete strength grades and different reinforcement ratios. Flexural capacities of concrete beams reinforced with 400 MPa, 500 MPa, and 600 MPa grade steel are analyzed based on equations in various codes and based on experimental studies in the literature. Furthermore, this study performs reliability analysis and verifies the three design values of 600 MPa grade steel yield strength in relation to the experimental performance and recommends the appropriate design values of 600 MPa grade steel yield strength. Research results show that when the measured values of yield strength of the steel bars and concrete strength are used, the ratio of the measured failure moment value to the calculated value for various beams based on different codes is nearly 1.0, demonstrating the high degree of fitting. Finally, the reliability analysis shows that the design yield strength of the 600 MPa grade high‐strength steel bars should be taken as 520 MPa.