scholarly journals Risk-Oriented Product Assembly System Health Modeling and Predictive Maintenance Strategy

Sensors ◽  
2019 ◽  
Vol 19 (9) ◽  
pp. 2086 ◽  
Author(s):  
Fengdi Liu ◽  
Yihai He ◽  
Yixiao Zhao ◽  
Anqi Zhang ◽  
Di Zhou
Keyword(s):  
Health Risk ◽  
High Reliability ◽  
Health Assessment ◽  
Assessment Method ◽  
Predictive Maintenance ◽  
Assembly System ◽  
Health State ◽  
Maintenance Strategy ◽  
Health States ◽  
Operational Data

Assembly quality is the barometer of assembly system health, and a healthy assembly system is an important physical guarantee for producing reliable products. Therefore, for ensuring the high reliability of products, the operational data of the assembly system should be analyzed to manage health states. Therefore, based on the operational data of the assembly system collected by intelligent sensors, from the perspective of quality control based on risk thinking, a risk-oriented health assessment method and predictive maintenance strategy for managing assembly system health are proposed. First, considering the loss of product reliability, the concept of assembly system health risk is proposed, and the risk formation mechanism is expounded. Second, the process variation data of key reliability characteristics (KRCs) collected by different sensors are used to measure and assess the health risk of the running assembly system to evaluate the health state. Third, the assembly system health risk is used as the maintenance threshold, the predictive maintenance decision model is established, and the optimal maintenance strategy is determined through stepwise optimization. Finally, the case study verifies the effectiveness and superiority of the proposed method. Results show that the proposed method saves 37.40% in costs compared with the traditional method.

scholarly journals Bearing Health Assessment Based on Chaotic Characteristics

2013 ◽  
Vol 20 (3) ◽  
pp. 519-530 ◽  
Author(s):  
Chen Lu ◽  
Qian Sun ◽  
Laifa Tao ◽  
Hongmei Liu ◽  
Chuan Lu
Keyword(s):  
Health Assessment ◽  
Vibration Signal ◽  
Assessment Method ◽  
Largest Lyapunov Exponent ◽  
Health State ◽  
Self Organizing Map ◽  
Linear Complex ◽  
Vibration Signals ◽  
Confidence Value

Vibration signals extracted from rotating parts of machinery carry a lot of useful information about the condition of operating machine. Due to the strong non-linear, complex and non-stationary characteristics of vibration signals from working bearings, an accurate and reliable health assessment method for bearing is necessary. This paper proposes to utilize the selected chaotic characteristics of vibration signal for health assessment of a bearing by using self-organizing map (SOM). Both Grassberger-Procaccia algorithm and Takens' theory are employed to calculate the characteristic vector which includes three chaotic characteristics, such as correlation dimension, largest Lyapunov exponent and Kolmogorov entropy. After that, SOM is used to map the three corresponding characteristics into a confidence value (CV) which represents the health state of the bearing. Finally, a case study based on vibration datasets of a group of testing bearings was conducted to demonstrate that the proposed method can reliably assess the health state of bearing.

scholarly journals Cost-oriented predictive maintenance based on mission reliability state for cyber manufacturing systems

2018 ◽  
Vol 10 (1) ◽  
pp. 168781401775146 ◽  
Author(s):  
Yihai He ◽  
Xiao Han ◽  
Changchao Gu ◽  
Zhaoxiang Chen
Keyword(s):  
Preventive Maintenance ◽  
Manufacturing Systems ◽  
Predictive Analytics ◽  
Predictive Maintenance ◽  
Dynamic State ◽  
Maintenance Strategy ◽  
Health States ◽  
Decision Making Problem ◽  
Periodic Preventive Maintenance ◽  
Maintenance Mode

With the advent of Industry 4.0, maintenance strategy faces new demands to avoid the hysteresis of the conventional passive maintenance mode and the non-feasibility of the periodic preventive maintenance model. In view of the inherent polymorphism of manufacturing systems and with the objective of maximizing benefits, a novel cost-oriented predictive maintenance based on mission reliability state for manufacturing systems is proposed. First, the cyber-physical system is adopted to organize and analyze big data in the operational process of manufacturing systems in terms of predictive analytics in cyber manufacturing environment. Second, a new connotation of mission reliability is defined based on the big operational data to comprehensively characterize the dynamic state of the equipment health states and the qualified degree of the production task. Third, the predictive maintenance mode based on mission reliability state is quantified by the comprehensive cost, and the relationship between mission reliability and cost is established. Thereafter, cost-oriented dynamic predictive maintenance strategy is proposed. Finally, a case study on the maintenance decision-making problem of a cylinder head manufacturing system is presented. The final result shows that the comprehensive cost can be further reduced by the proposed method relative to the traditional periodic preventive maintenance strategy.

Estimating Utility Values for Health States of DFU Patients Using EQ-5D-5L and cTTO

2021 ◽  
pp. 153473462110143
Author(s):  
Morteza Arab-Zozani ◽  
Hossein Safari ◽  
Zoha Dori ◽  
Somayeh Afshari ◽  
Hosein Ameri ◽  
...  
Keyword(s):  
Foot Ulcer ◽  
Diabetic Foot Ulcer ◽  
Economic Modeling ◽  
Health State ◽  
Health States ◽  
Utility Values ◽  
The Mean ◽  
The Difference ◽  
Diabetes Center ◽  
Health State Utility Values

Health-state utility values of diabetic foot ulcer (DFU) patients are necessary for clinical praxis and economic modeling. The purpose of this study was to estimate utility values in DFU patients using the EuroQol-5-dimension-5-level (EQ-5D-5L) and composite time trade-off (cTTO). The EQ-5D-5L and cTTO were used for estimating utility values. Data were collected from 228 patients referred to the largest governmental diabetes center in the South of Iran, Yazd province. When appropriate, independent sample t-test or analysis of variance test was used to test the difference in the utility values in each of the demographic and clinical characteristics of the patients. Finally, the BetaMix was used to identify predictors of the utility values. The means of EQ-5D-5L and cTTO values were 0.55( SD 0.21) and 0.67( SD 0.23), respectively. Anxiety and pain were the most common problems reported by the patients. The difference between the mean EQ-5D-5L values was significant for age, grade of ulcer, number of comorbidities, and having complications. In addition, variables of gender, age, grade of ulcer, and having complications were significant predictors of the EQ-5D-5L. The difference between the mean cTTO values was significant for age, employment status, grade of ulcer, number of comorbidities, and having complications. Moreover, variables of gender, age, grade of ulcer, number of comorbidities, and developing complications were significant predictors of cTTO. The current study provided estimates of utility values for DFU patients for clinical praxis and economic modeling. These estimates, similar to utilities reported in other studies, were low. Identifying strategies to decrease anxiety/depression and pain in patients is important to improve the utility values.

scholarly journals Estimating an EQ-5D-3L Value Set for Romania Using Time Trade-Off

2021 ◽  
Vol 18 (14) ◽  
pp. 7415
Author(s):  
Marian Sorin Paveliu ◽  
Elena Olariu ◽  
Raluca Caplescu ◽  
Yemi Oluboyede ◽  
Ileana-Gabriela Niculescu-Aron ◽  
...  
Keyword(s):  
Health Technology Assessment ◽  
Technology Assessment ◽  
Health Technology ◽  
Assessment Process ◽  
Computer Assisted ◽  
Health State ◽  
Health States ◽  
Value Set ◽  
Health Technologies ◽  
Related Quality

Objective: To provide health-related quality of life (HRQoL) data to support health technology assessment (HTA) and reimbursement decisions in Romania, by developing a country-specific value set for the EQ-5D-3L questionnaire. Methods: We used the cTTO method to elicit health state values using a computer-assisted personal interviewing approach. Interviews were standardized following the most recent version of the EQ-VT protocol developed by the EuroQoL Foundation. Thirty EQ-5D-3L health states were randomly assigned to respondents in blocks of three. Econometric modeling was used to estimate values for all 243 states described by the EQ-5D-3L. Results: Data from 1556 non-institutionalized adults aged 18 years and older, selected from a national representative sample, were used to build the value set. All tested models were logically consistent; the final model chosen to generate the value set was an interval regression model. The predicted EQ-5D-3L values ranged from 0.969 to 0.399, and the relative importance of EQ-5D-3L dimensions was in the following order: mobility, pain/discomfort, self-care, anxiety/depression, and usual activities. Conclusions: These results can support reimbursement decisions and allow regional cross-country comparisons between health technologies. This study lays a stepping stone in the development of a health technology assessment process more driven by locally relevant data in Romania.

scholarly journals Metal Contents in Fish from the Bay of Bengal and Potential Consumer Exposure—The EAF-Nansen Programme

Foods ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 1147
Author(s):  
Amalie Moxness Reksten ◽  
Zillur Rahman ◽  
Marian Kjellevold ◽  
Esther Garrido Gamarro ◽  
Shakuntala H. Thilsted ◽  
...  
Keyword(s):  
Health Risk ◽  
Bay Of Bengal ◽  
Health Assessment ◽  
Sri Lankan ◽  
Marine Fish Species ◽  
Daily Consumption ◽  
Potential Health ◽  
Potential Consumer ◽  
Metal Contents ◽  
Adults And Children

Fish represent an important part of the Sri Lankan and Bangladeshi diet. However, fish is also a source of contaminants that may constitute a health risk to consumers. The aim of this study was to analyse the contents of arsenic, cadmium, mercury, and lead in 24 commonly consumed marine fish species from the Bay of Bengal and to assess the potential health risk associated with their consumption. Mercury and lead contents did not exceed the maximum limits for any of the sampled species, and consumer exposure from estimated daily consumption was assessed to be minimal for adults and children. Numerous samples exceeded the maximum limit for cadmium (58%), particularly those of small size (≤25 cm). However, consumer exposure was insignificant, and health assessment showed no risk connected to consumption. These data represent an important contribution to future risk/benefit assessments related to the consumption of fish.

scholarly journals NCOG-36. FIRST HEALTH UTILITIES OF GLIOBLASTOMA PATIENTS USING TTFIELDS TREATMENT

2020 ◽  
Vol 22 (Supplement_2) ◽  
pp. ii137-ii137
Author(s):  
Gordon Chavez ◽  
Christina Proescholdt
Keyword(s):  
Population Sample ◽  
National Health System ◽  
Medical Decision ◽  
Economic Evaluations ◽  
Health State ◽  
High Quality ◽  
Health States ◽  
Tumor Treating Fields ◽  
Health State Utilities ◽  
The Uk

Abstract BACKGROUND Despite the importance of Health State Utilities for health policy and medical decision making, there are no publications that provide high quality utility values estimated from glioblastoma multiforme (GBM) patients. Published health economic evaluations for GBM treatments rely on utilities determined by Garside et al. (2007), which used the standard gamble method in healthy panel members of the UK National Health System. There are no published utilities for GBM estimated from a general population sample, and there are no utility estimates whatsoever for Tumor Treating Fields (TTFields) users. METHODS We designed a study to remedy this major deficit by eliciting utilities directly from GBM patients using the EuroQol 5-Dimension (EQ-5D) survey. The EQ-5D is a widely used and NICE-recommended tool for the estimation of health state utilities. The survey is composed of a questionnaire that asks patients to specify their health state along 5 dimensions: Mobility, Self-Care, Usual Activities, Pain/Discomfort, and Anxiety/Depression. Statistical models provided by EuroQol’s network of researchers convert this data into health state utility estimates. RESULTS The EQ-5D questionnaire is administered to active patients using TTFields treatment during the study duration, allowing the elicitation of health preference measures for different glioblastoma health states based on: progression status (progressed vs. non-progressed), current treatments (TTFields only vs. TTFields + others) and time-from-diagnosis (0-12 months vs. > 12 months) CONCLUSION These results are important for understanding the patient preferences using TTFields treatment and communicating these preferences to decision makers. This study is the first to provide direct, high quality utility measures in glioblastoma patients using TTFields treatment.

scholarly journals Valuation of the EQ-5D-3L in Russia

2021 ◽  
Author(s):  
Vitaly Omelyanovskiy ◽  
Nuriya Musina ◽  
Svetlana Ratushnyak ◽  
Tatiana Bezdenezhnykh ◽  
Vlada Fediaeva ◽  
...  
Keyword(s):  
Health Problems ◽  
Cost Utility ◽  
Economic Evaluations ◽  
Computer Assisted ◽  
Health State ◽  
Primary Analysis ◽  
Health States ◽  
Value Set ◽  
Model Combining ◽  
Life Years

Abstract Purpose The most widely used generic questionnaire to estimate the quality of life for yielding quality-adjusted life years in economic evaluations is EQ-5D. Country-specific population value sets are required to use EQ-5D in economic evaluations. The aim of this study was to establish an EQ-5D-3L value set for Russia. Methods A representative sample aged 18+ years was recruited from the Russia`s general population. Computer-assisted face–to–face interviews were conducted based on the standardized valuation protocol using EQ-Portable Valuation Technology. Population preferences were elicited utilizing both composite time trade-off (cTTO) and discrete choice experiment (DCE) techniques. To estimate the value set, a hybrid regression model combining cTTO and DCE data was used. Results A total of 300 respondents who successfully completed the interview were included in the primary analysis. 120 (40.0%) respondents reported no health problems of any dimension, and 56 (18.7%) reported moderate health problems in one dimension of the EQ‐5D‐3L. Median self-rated health using EQ‐VAS was 80 with IQR 70–90. Comparing cTTO and DCE-predicted values for 243 health states resulted in a similar pattern. This supports the use of hybrid models. The predicted value based on the preferred model for the worst health state “33333” was −0.503. Mobility dimension had the most significant impact on the utility decrement, and anxiety/depression had the lowest decrement. Conclusion Determining a Russian national value set may be considered the first step towards promoting cost-utility analysis use to increase comparability among studies and improve the transferability of healthcare decision-making in Russia.

scholarly journals Online Health Management for Complex Nonlinear Systems Based on Hidden Semi-Markov Model Using Sequential Monte Carlo Methods

2012 ◽  
Vol 2012 ◽  
pp. 1-22
Author(s):  
Qinming Liu ◽  
Ming Dong
Keyword(s):  
Monte Carlo ◽  
Nonlinear System ◽  
Nonlinear Systems ◽  
Markov Model ◽  
Sequential Monte Carlo ◽  
Health Management ◽  
Health State ◽  
Health States ◽  
Complex Nonlinear System ◽  
Complex Nonlinear Systems

Health management for a complex nonlinear system is becoming more important for condition-based maintenance and minimizing the related risks and costs over its entire life. However, a complex nonlinear system often operates under dynamically operational and environmental conditions, and it subjects to high levels of uncertainty and unpredictability so that effective methods for online health management are still few now. This paper combines hidden semi-Markov model (HSMM) with sequential Monte Carlo (SMC) methods. HSMM is used to obtain the transition probabilities among health states and health state durations of a complex nonlinear system, while the SMC method is adopted to decrease the computational and space complexity, and describe the probability relationships between multiple health states and monitored observations of a complex nonlinear system. This paper proposes a novel method of multisteps ahead health recognition based on joint probability distribution for health management of a complex nonlinear system. Moreover, a new online health prognostic method is developed. A real case study is used to demonstrate the implementation and potential applications of the proposed methods for online health management of complex nonlinear systems.

Integrity Assessment of Non-Piggable Pipeline Through Direct Assessment

2013 ◽  
Author(s):  
Jai Prakash Sah ◽  
Mohammad Tanweer Akhter
Keyword(s):  
Hydrostatic Pressure ◽  
Natural Gas ◽  
Stress Corrosion ◽  
Health Assessment ◽  
Assessment Method ◽  
Pipeline System ◽  
Internal Corrosion ◽  
Integrity Assessment ◽  
Direct Assessment ◽  
External Corrosion

Managing the integrity of pipeline system is the primary goal of every pipeline operator. To ensure the integrity of pipeline system, its health assessment is very important and critical for ensuring safety of environment, human resources and its assets. In long term, managing pipeline integrity is an investment to asset protection which ultimately results in cost saving. Typically, the health assessment to managing the integrity of pipeline system is a function of operational experience and corporate philosophy. There is no single approach that can provide the best solution for all pipeline system. Only a comprehensive, systematic and integrated integrity management program provides the means to improve the safety of pipeline systems. Such programme provides the information for an operator to effectively allocate resources for appropriate prevention, detection and mitigation activities that will result in improved safety and a reduction in the number of incidents. Presently GAIL (INDIA) LTD. is operating & maintaining approximately 10,000Kms of natural gas/RLNG/LPG pipeline and HVJ Pipeline is the largest pipeline network of India which transports more than 50% of total gas being consumed in this country. HVJ pipeline system consists of more than 4500 Kms of pipeline having diameter range from 04” to 48”, which consist of piggable as well as non-piggable pipeline. Though, lengthwise non-piggable pipeline is very less but their importance cannot be ignored in to the totality because of their critical nature. Typically, pipeline with small length & connected to dispatch terminal are non-piggable and these pipelines are used to feed the gas to the consumer. Today pipeline industries are having three different types of inspection techniques available for inspection of the pipeline. 1. Inline inspection 2. Hydrostatic pressure testing 3. Direct assessment (DA) Inline inspection is possible only for piggable pipeline i.e. pipeline with facilities of pig launching & receiving and hydrostatic pressure testing is not possible for the pipeline under continuous operation. Thus we are left with direct assessment method to assess health of the non-piggable pipelines. Basically, direct assessment is a structured multi-step evaluation method to examine and identify the potential problem areas relating to internal corrosion, external corrosion, and stress corrosion cracking using ICDA (Internal Corrosion Direct Assessment), ECDA (External Corrosion Direct Assessment) and SCCDA (Stress Corrosion Direct Assessment). All the above DA is four steps iterative method & consist of following steps; a. Pre assessment b. Indirect assessment c. Direct assessment d. Post assessment Considering the importance of non-piggable pipeline, integrity assessment of following non piggable pipeline has done through direct assessment method. 1. 30 inch dia pipeline of length 0.6 km and handling 18.4 MMSCMD of natural gas 2. 18 inch dia pipeline of length 3.65 km and handling 4.0 MMSCMD of natural gas 3. 12 inch dia pipeline of length 2.08 km and handling 3.4 MMSCMD of natural gas In addition to ICDA, ECDA & SCCDA, Long Range Ultrasonic Thickness (LRUT-a guided wave technology) has also been carried out to detect the metal loss at excavated locations observed by ICDA & ECDA. Direct assessment survey for above pipelines has been conducted and based on the survey; high consequence areas have been identified. All the high consequence area has been excavated and inspected. No appreciable corrosion and thickness loss have observed at any area. However, pipeline segments have been identified which are most vulnerable and may have corrosion in future.

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