Sample selection of prognostics validation test based on multi-stage Wiener process

2018 ◽  
Vol 233 (4) ◽  
pp. 605-614
Author(s):  
Zhiao Zhao ◽  
Yong Zhang ◽  
Guanjun Liu ◽  
Jing Qiu
Keyword(s):  
Wiener Process ◽  
Process Model ◽  
Failure Modes ◽  
Early Stage ◽  
Sample Selection ◽  
Degradation Process ◽  
Time Interval ◽  
Degradation Data ◽  
Multi Stage ◽  
Selection Of

Sample allocation and selection technology is of great significance in the test plan design of prognostics validation. Considering the existing researches, the importance of prognostics samples of different moments is not considered in the degradation process of a single failure. Normally, prognostics samples are generated under the same time interval mechanism. However, a prognostics system may have low prognostics accuracy because of the small quantity of failure degradation and measurement randomness in the early stage of a failure degradation process. Historical degradation data onto equipment failure modes are collected, and the degradation process model based on the multi-stage Wiener process is established. Based on the multi-stage Wiener process model, we choose four parameters to describe different degradation stages in a degradation process. According to four parameters, the sample selection weight of each degradation stage is calculated and the weight of each degradation stage is used to select prognostics samples. Taking a bearing wear fault of a helicopter transmission device as an example, its degradation process is established and sample selection weights are calculated. According to the sample selection weight of each degradation process, we accomplish the prognostics sample selection of the bearing wear fault. The results show that the prognostics sample selection method proposed in this article has good applicability.

Two-Phase Degradation Process Model With Abrupt Jump at Change Point Governed by Wiener Process

2017 ◽  
Vol 66 (4) ◽  
pp. 1345-1360 ◽  
Author(s):  
Dejing Kong ◽  
Narayanaswamy Balakrishnan ◽  
Lirong Cui
Keyword(s):  
Wiener Process ◽  
Change Point ◽  
Process Model ◽  
Degradation Process ◽  
Two Phase ◽  
Abrupt Jump

scholarly journals Strategi Pemasaran Agribisnis Ikan Nila Dalam Di Kecamatan Babirik Kabupaten Hulu Sungai Utara

2013 ◽  
Vol 3 (1) ◽  
pp. 116-123
Author(s):  
Rum Van Royensyah
Keyword(s):  
Sampling Method ◽  
Sample Selection ◽  
Internal Factor ◽  
Internal Factors ◽  
Multi Stage ◽  
Group Members ◽  
Factor Evaluation ◽  
Production Strategy ◽  
Evaluation Matrix ◽  
Selection Of

       This study aims to analyze the strategy of developing tilapia agribusiness in Babirik District, North Hulu Sungai Regency. Sampling was done by multi stage sampling and the selection of sub-district locations was carried out by purposive sampling method, namely the sub-districts which most cultivated tilapia in karamba, namely Babirik District. Fish farmers as samples were selected by stratified proportional random sampling, as many as 8 people (30% of 27 UPP group members), and 57 people (30% of 191 were not UPP group members). The number of samples is 65 people. Collector samples (collectors) were selected by snow ball sampling, which was 20 people (30% of 65 collectors). The sample of retailers was chosen by accidental sampling in the fish market in North Hulu Sungai Regency, as many as 5 people. The selection of Fisheries UPP internal factor samples was 8 people (30% of 27 people), and the sample selection of non Fisheries UPP internal factors was 20 people (30% of 191 people), while 2 external factors were selected from the relevant institutions. The results of the internal factor evaluation matrix are 3,163, while the results of the external factor evaluation matrix are 2,538. The results of the internal external matrix are in cell IV, namely in the growth and building position, and the indigo agribusiness strategy in karamba in Babirik District is a market development and production strategy.

scholarly journals Accelerated Degradation Process Analysis Based on the Nonlinear Wiener Process with Covariates and Random Effects

2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
Li Sun ◽  
Xiaohui Gu ◽  
Pu Song
Keyword(s):  
Diffusion Coefficient ◽  
Wiener Process ◽  
Random Effects ◽  
Process Analysis ◽  
Likelihood Estimation ◽  
Degradation Process ◽  
Unknown Parameters ◽  
Accelerated Degradation ◽  
Degradation Data ◽  
Drift Parameter

It is assumed that the drift parameter is dependent on the acceleration variables and the diffusion coefficient remains the same across the whole accelerated degradation test (ADT) in most of the literature based on Wiener process. However, the diffusion coefficient variation would also become obvious in some applications with the stress increasing. Aiming at the phenomenon, the paper concludes that both the drift parameter and the diffusion parameter depend on stress variables based on the invariance principle of failure mechanism and Nelson assumption. Accordingly, constant stress accelerated degradation process (CSADP) and step stress accelerated degradation process (SSADP) with random effects are modeled. The unknown parameters in the established model are estimated based on the property of degradation and degradation increment, separately for CASDT and SSADT, by the maximum likelihood estimation approach with measurement error. In addition, the simulation steps of accelerated degradation data are provided and simulated step stress accelerated degradation data is designed to validate the proposed model compared to other models. Finally, a case study of CSADT is conducted to demonstrate the benefits of our model in the practical engineering.

The Architect Test Sample Selection Model and its Application Based on Genetic Algorithm

2012 ◽  
Vol 174-177 ◽  
pp. 2029-2035
Author(s):  
Qiang Li ◽  
Hui Min Li ◽  
Hai Lan Jiang ◽  
Feng Yuan
Keyword(s):  
Genetic Algorithm ◽  
Process Model ◽  
Sample Selection ◽  
Test Sample ◽  
Selection Model ◽  
Model Property ◽  
Sample Selection Model ◽  
Model Sample ◽  
Property Model ◽  
Selection Of

This paper introduces the researches and applications based on genetic algorithm in the sample selection of papers. We followed the steps of the work and separate the model of four sub models: the pre-process model, sample selection model, property model and reefed model. We consider form all aspect which may affects the decision of sample selection and solve them. Form the instance, the genetic algorithm we discussed can improve the reliability and efficiency of the national first degree architecture test on some degree.

scholarly journals Methodical Approach for Process Selection in Additive Manufacturing

2019 ◽  
Vol 1 (1) ◽  
pp. 779-788
Author(s):  
Nadine Wortmann ◽  
Christoph Jürgenhake ◽  
Tobias Seidenberg ◽  
Roman Dumitrescu ◽  
Dieter Krause
Keyword(s):  
Additive Manufacturing ◽  
Process Model ◽  
Early Stage ◽  
Cost Model ◽  
Methodological Approach ◽  
Reaction Times ◽  
Design Guidelines ◽  
Process Selection ◽  
Potential Part ◽  
Selection Of

AbstractIn recent years, rapid technical progress has led to additive manufacturing achieving a high degree of technological maturity that enables a broad range of applications. This is reinforced in particular by the advantages of the technology, such as the production of complex components, smaller quantities and fast reaction times. However, a lack of knowledge of the various process techniques, such as insufficient potential assessment, specific design guidelines or even of process restrictions, often lead to different errors.This paper presents a methodological approach to support designers in the manufacturing process selection of specific parts at an early stage of product development. In a four-stage procedure, potential part candidates are first identified and part classes formed on the basis of characteristics. Building on this, AM thinking is to be stimulated, for example, with the aid of design guidelines. A comparison between conventionally and additively manufactured parts can be made using a simplified cost model. The results are incorporated into a process model that supports companies in the systematic selection of manufacturing processes.

scholarly journals Synovium-Synovial Fluid Axis in Osteoarthritis Pathology: A Key Regulator of the Cartilage Degradation Process

Genes ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 989
Author(s):  
Dhanashri Ingale ◽  
Priya Kulkarni ◽  
Ali Electricwala ◽  
Alpana Moghe ◽  
Sara Kamyab ◽  
...  
Keyword(s):  
Synovial Fluid ◽  
Early Stage ◽  
Challenge Test ◽  
Degradation Process ◽  
Cartilage Degradation ◽  
Gene Expressions ◽  
Inflammatory Microenvironment ◽  
Protein Levels ◽  
Advanced Stages ◽  
Inflammatory Milieu

Failure of conventional anti-inflammatory therapies in osteoarthritis (OA) underlines the insufficient knowledge about inflammatory mechanisms, patterns and their relationship with cartilage degradation. Considering non-linear nature of cartilage loss in OA, a better understanding of inflammatory milieu and MMP status at different stages of OA is required to design early-stage therapies or personalized disease management. For this, an investigation based on a synovium-synovial fluid (SF) axis was planned to study OA associated changes in synovium and SF along the progressive grades of OA. Gene expressions in synovial-biopsies from different grades OA patients (N = 26) revealed a peak of IL-1β, IL-15, PGE2 and NGF in early OA (Kellgren–Lawrence (KL) grade-I and II); the highest MMP levels were found in advanced stages (KL grade-III and IV). MMPs (MMP-1, 13, 2 and 9) abundance and FALGPA activity estimated in forty SFs of progressive grades showed the maximum protein levels and activity in KL grade-II and III. In an SF challenge test, SW982 and THP1 cells were treated with progressive grade SFs to study the dynamics of MMPs modulation in inflammatory microenvironment; the test yielded a result pattern, which matched with FALGPA and the protein-levels estimation. Inflammatory mediators in SFs served as steering factor for MMP up-regulation. A correlation-matrix of IL-1β and MMPs revealed expressional negative correlation.

scholarly journals Temporal changes of quantitative CT findings from 102 patients with COVID-19 in Wuhan, China: A longitudinal study

2021 ◽  
Vol 29 ◽  
pp. 297-309
Author(s):  
Xiaohui Chen ◽  
Wenbo Sun ◽  
Dan Xu ◽  
Jiaojiao Ma ◽  
Feng Xiao ◽  
...  
Keyword(s):  
Lung Diseases ◽  
Early Stage ◽  
Temporal Changes ◽  
Time Interval ◽  
Lesion Area ◽  
Quantitative Ct ◽  
Diagnosis And Prognosis ◽  
Ct Findings ◽  
Stage 4 ◽  
Stage 1

BACKGROUND: Computed tomography (CT) imaging combined with artificial intelligence is important in the diagnosis and prognosis of lung diseases. OBJECTIVE: This study aimed to investigate temporal changes of quantitative CT findings in patients with COVID-19 in three clinic types, including moderate, severe, and non-survivors, and to predict severe cases in the early stage from the results. METHODS: One hundred and two patients with confirmed COVID-19 were included in this study. Based on the time interval between onset of symptoms and the CT scan, four stages were defined in this study: Stage-1 (0 ∼7 days); Stage-2 (8 ∼ 14 days); Stage-3 (15 ∼ 21days); Stage-4 (> 21 days). Eight parameters, the infection volume and percentage of the whole lung in four different Hounsfield (HU) ranges, ((-, -750), [-750, -300), [-300, 50) and [50, +)), were calculated and compared between different groups. RESULTS: The infection volume and percentage of four HU ranges peaked in Stage-2. The highest proportion of HU [-750, 50) was found in the infected regions in non-survivors among three groups. CONCLUSIONS: The findings indicate rapid deterioration in the first week since the onset of symptoms in non-survivors. Higher proportion of HU [-750, 50) in the lesion area might be a potential bio-marker for poor prognosis in patients with COVID-19.

scholarly journals Evaluation of Energy Absorption Capabilities of Polyethylene Foam under Impact Deformation

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3613
Author(s):  
Baohui Yang ◽  
Yangjie Zuo ◽  
Zhengping Chang
Keyword(s):  
Energy Absorption ◽  
Failure Modes ◽  
High Strain ◽  
Early Stage ◽  
High Energy ◽  
Test Method ◽  
Test Theory ◽  
Strain Rates ◽  
Impact Properties ◽  
The Impact

Foams are widely used in protective applications requiring high energy absorption under impact, and evaluating impact properties of foams is vital. Therefore, a novel test method based on a shock tube was developed to investigate the impact properties of closed-cell polyethylene (PE) foams at strain rates over 6000 s−1, and the test theory is presented. Based on the test method, the failure progress and final failure modes of PE foams are discussed. Moreover, energy absorption capabilities of PE foams were assessed under both quasi-static and high strain rate loading conditions. The results showed that the foam exhibited a nonuniform deformation along the specimen length under high strain rates. The energy absorption rate of PE foam increased with the increasing of strain rates. The specimen energy absorption varied linearly in the early stage and then increased rapidly, corresponding to a uniform compression process. However, in the shock wave deformation process, the energy absorption capacity of the foam maintained a good stability and exhibited the best energy absorption state when the speed was higher than 26 m/s. This stable energy absorption state disappeared until the speed was lower than 1.3 m/s. The loading speed exhibited an obvious influence on energy density.

scholarly journals Membrane Distillation for the Production of Pharmaceutical-Grade Water—Investigation into the Application of AGMD and VMD

2021 ◽  
Vol 18 (11) ◽  
pp. 6058
Author(s):  
Cornelius Nellessen ◽  
Thomas Klein ◽  
Hans-Jürgen Rapp ◽  
Frank Rögener
Keyword(s):  
Energy Demand ◽  
Tap Water ◽  
Membrane Distillation ◽  
Pharmaceutical Products ◽  
Optimum Process ◽  
The European Union ◽  
Pharmaceutical Ingredients ◽  
Multi Stage ◽  
One Step ◽  
Selection Of

The production of pharmaceutical ingredients, intermediates and final products strongly depends on the utilization of water. Water is also required for the purification and preparation of reagents. Each specific application determines the respective water quality. In the European Union, the European Pharmacopeia (Ph. Eur.) contains the official standards that assure quality control of pharmaceutical products during their life cycle. According to this, the production of water for pharmaceutical use is mainly based on multi-stage distillation and membrane processes, especially, reverse osmosis. Membrane distillation (MD) could be an alternative process to these classical methods. It offers advantages in terms of energy demand and a compact apparatus design. In the following study, the preparation of pharmaceutical-grade water from tap water in a one-step process using MD is presented. Special emphasis is placed on the performance of two different module designs and on the selection of optimum process parameters.

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