scholarly journals On the functional safety of a complex technical control system with digital twins

Dependability ◽  
2021 ◽  
Vol 21 (1) ◽  
pp. 38-44
Author(s):  
I. B. Shubinsky ◽  
Hendrik Schabe ◽  
E. N. Rozenberg
Keyword(s):  
Time To Failure ◽  
Wrong Side ◽  
Safety Improvement ◽  
Digital Twins ◽  
Technical Control ◽  
Initial Item ◽  
Additional Costs ◽  
System Developer ◽  
The Mean ◽  
Mean Time

The Aim of this paper is to evaluate the advantages of digital twin technology as compared with the conventional approaches to the design of a vital two-channel system. Methods. The system is described with a Markovian model. This model allows defining the quantitative safety characteristics if the system is affected by right-side failures. Results. The system’s primary quantitative safety indicators were identified as the mean time to wrong-side failure and mean time to right-side failure along with the quantitative relations of the prime and additional costs for a batch of products. Conclusion. Transforming the initial item into a system with digital twins allows significantly reducing the rate of wrong-side failures. This effect may be obtained not only with the use of digital twins, but also as the result of the system transitioning into the state of right-side failure in each event of discrepancy betwin the initial item and/or the digital twins. It has been established that the mean time to right-side failure under such conditions is not less than the mean time to failure of the initial item. That means that highly efficient measures for safety improvement allow maintaining the system dependability at a level not lower than that of the initial item. The introduction of digital twins into a system is a new, not yet tested way of ensuring system safety. The decision on the benefits of additional costs is taken by the customer and system developer together. At the same time, it must be taken into consideration that in case of large batches of manufactured technical systems, the effect of additional costs is reduced and the effect of significantly improved safety is maintained.

scholarly journals Surveillance System in Smart Cities: A Dependability Evaluation Based on Stochastic Models

Electronics ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 876
Author(s):  
Igor Gonçalves ◽  
Laécio Rodrigues ◽  
Francisco Airton Silva ◽  
Tuan Anh Nguyen ◽  
Dugki Min ◽  
...  
Keyword(s):  
Surveillance System ◽  
Smart Cities ◽  
Heterogeneous Data ◽  
Time To Failure ◽  
Video Streams ◽  
Dependability Evaluation ◽  
The Mean ◽  
Mean Time ◽  
The Internet Of Things

Surveillance monitoring systems are highly necessary, aiming to prevent many social problems in smart cities. The internet of things (IoT) nowadays offers a variety of technologies to capture and process massive and heterogeneous data. Due to the fact that (i) advanced analyses of video streams are performed on powerful recording devices; while (ii) surveillance monitoring services require high availability levels in the way that the service must remain connected, for example, to a connection network that offers higher speed than conventional connections; and that (iii) the trust-worthy dependability of a surveillance system depends on various factors, it is not easy to identify which components/devices in a system architecture have the most impact on the dependability for a specific surveillance system in smart cities. In this paper, we developed stochastic Petri net models for a surveillance monitoring system with regard to varying several parameters to obtain the highest dependability. Two main metrics of interest in the dependability of a surveillance system including reliability and availability were analyzed in a comprehensive manner. The analysis results show that the variation in the number of long-term evolution (LTE)-based stations contributes to a number of nines (#9s) increase in availability. The obtained results show that the variation of the mean time to failure (MTTF) of surveillance cameras exposes a high impact on the reliability of the system. The findings of this work have the potential of assisting system architects in planning more optimized systems in this field based on the proposed models.

On classes of life distributions based on the mean time to failure function

2021 ◽  
Vol 58 (2) ◽  
pp. 289-313
Author(s):  
Ruhul Ali Khan ◽  
Dhrubasish Bhattacharyya ◽  
Murari Mitra
Keyword(s):  
Damage Model ◽  
Replacement Policy ◽  
Time To Failure ◽  
Mean Time To Failure ◽  
Moment Convergence ◽  
Life Distributions ◽  
Cumulative Damage Model ◽  
The Mean ◽  
Age Replacement ◽  
Mean Time

AbstractThe performance and effectiveness of an age replacement policy can be assessed by its mean time to failure (MTTF) function. We develop shock model theory in different scenarios for classes of life distributions based on the MTTF function where the probabilities $\bar{P}_k$ of surviving the first k shocks are assumed to have discrete DMTTF, IMTTF and IDMTTF properties. The cumulative damage model of A-Hameed and Proschan [1] is studied in this context and analogous results are established. Weak convergence and moment convergence issues within the IDMTTF class of life distributions are explored. The preservation of the IDMTTF property under some basic reliability operations is also investigated. Finally we show that the intersection of IDMRL and IDMTTF classes contains the BFR family and establish results outlining the positions of various non-monotonic ageing classes in the hierarchy.

Điều trị tăng liều Imatinib trên bệnh nhân u mô đệm đường tiêu hoá giai đoạn muộn tiến triển sau điều trị bước 1 liều chuẩn

2020 ◽  
Author(s):  
Kien Do Hung
Keyword(s):  
Primary Tumor ◽  
Standard Dose ◽  
Performance Status ◽  
Gastric Tumor ◽  
High Dose ◽  
Time To Failure ◽  
Gastrointestinal Stromal Tumours ◽  
Mean Time To Failure ◽  
The Mean ◽  
Mean Time

Objective: Evaluating the result of high-dose imatinib for metastatic gastrointestinal stromal tumours after failure standard-dose first line. Patients and method: Restrospective analysis of 46 patients with metastatic gastrointestinal stromal tumours after failure standard-dose imatinib treated with high-dose imatinib at K hospital from 1/2015 đến 10/2019. Results: Median age was 54.6±9.5, male was 58.7%. The common primary tumor was gastric tumor. The mean time to failure of imatinib standard-dose 400mg/day was 38.2±5.3 months. Liver lesions were the most common lesions progressed after imatinib standard-dose failure (71.7%), primary tumor progressed was 39.1%. There was no patient who had complete response with treatment, the proportion of partial response accounted for 21.7% and stable disease was 45.7%. The clinical benefit rate was 67.4%. The sex-female, primary gastric tumor, good ECOG performance status, neutrophils, hemoglobine and albumin before treatment were the significant prognostic factors affecting the treatment response, p <0.05. The mean time to failure was 22.5 ± 3.4 (months), (min: 2.0; max: 58.0), median was 11.0 months. Conclusion: Treatment of high-dose imatinib after failure standard-dose 400mg/day showed the efficacy and good tolerance in metastatic GISTs.

ELECTROCHEMICAL MIGRATION BEHAVIOR OF Sn-3.0Ag-0.5Cu SOLDER ALLOY UNDER THIN ELECTROLYTE LAYERS

2019 ◽  
Vol 26 (06) ◽  
pp. 1850208 ◽  
Author(s):  
BOKAI LIAO ◽  
WENFENG JIA ◽  
RUIYAN SUN ◽  
ZHENYU CHEN ◽  
XINGPENG GUO
Keyword(s):  
Solder Alloy ◽  
Electrochemical Migration ◽  
Migration Behavior ◽  
Time To Failure ◽  
Sac305 Solder ◽  
Maximum Value ◽  
The Mean ◽  
Mean Time ◽  
Observation Results

The electrochemical migration (ECM) behavior of Sn-3.0Ag-0.5Cu solder alloy under thin electrolyte layers was investigated using a technique based on the coupling of in situ electrochemical measurements and optical observation. Results showed that the mean time to failure first increased and then decreased as thickness of the electrolyte layer increased, the maximum value was present at 200[Formula: see text][Formula: see text]m. The higher the bias voltage applied, the faster was the rate of dendrite growth. And, Sn leaded the ECM of SAC305 solder alloy. Mechanisms relevant have been proposed to explain the ECM behavior of Sn-3.0Ag-0.5Cu solder alloy.

On estimating the mean time to failure with unknown censoring

1989 ◽  
Vol 38 (3) ◽  
pp. 343-347 ◽  
Author(s):  
R. Shanmugam ◽  
D.O. Richards
Keyword(s):  
Time To Failure ◽  
Mean Time To Failure ◽  
The Mean ◽  
Mean Time

RELIABILITY PROPERTIES OF MEAN TIME TO FAILURE IN AGE REPLACEMENT MODELS

2010 ◽  
Vol 17 (01) ◽  
pp. 15-26 ◽  
Author(s):  
G. ASHA ◽  
N. UNNIKRISHNAN NAIR
Keyword(s):  
Residual Life ◽  
Stochastic Orders ◽  
Mean Residual Life ◽  
Time To Failure ◽  
Mean Time To Failure ◽  
Replacement Model ◽  
The Mean ◽  
Age Replacement ◽  
The Relationship ◽  
Mean Time

In this article some properties of the mean time to failure in an age replacement model is presented by examining the relationship it has with hazard (reversed hazard) rate and mean (reversed mean) residual life functions. An ordering based on mean time to failure is used to examine its implications with other stochastic orders.

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