Reliability analysis of complex systems based on the probability dynamics of subsystem failures and deviation of parameters

Grishko, А. К.; Yurkov, N. К.; Goryachev, N. V.

doi:10.1109/cadsm.2017.7916109

Cited by 16 publications

(5 citation statements)

References 5 publications

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“…By turning to reliability engineering, we can see that as the number of independent elements increase in a complex machine, the reliability decreases. 29 , 30 Specifically, “it is the active interfaces (i.e., moving surfaces) that are the most common regions for failures to occur.” 30 Figure 3 shows mechanical faults as the prevailing issue, and it is established that leaf motors needing to be replaced accounts for a majority of the replacement resolutions. Having fewer leaves would decrease the number of leaf motors used and decrease the total contact surface area between leaves in an MLC.…”

Section: Discussionmentioning

confidence: 99%

“…An alternative that might cause the least amount of disruption to workflow is changing the parameters of the leaves or the design of the existing MLCs. By turning to reliability engineering, we can see that as the number of independent elements increase in a complex machine, the reliability decreases 29,30 . Specifically, “it is the active interfaces (i.e., moving surfaces) that are the most common regions for failures to occur.” 30 Figure 3 shows mechanical faults as the prevailing issue, and it is established that leaf motors needing to be replaced accounts for a majority of the replacement resolutions.…”

Section: Discussionmentioning

confidence: 99%

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Failure modes and downtime of radiotherapy LINACs and multileaf collimators in Indonesia

Pawiro

Kasim

et al. 2022

J Applied Clin Med Phys

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Background and purpose The lack of equitable access to radiotherapy (RA) linear accelerators (LINACs) is a substantial barrier to cancer care in low‐ and middle‐income countries (LMICs). These nations are expected to bear up to 75% of cancer‐related deaths globally by 2030. State‐of‐the‐art LINACs in LMICs experience major issues in terms of robustness, with mechanical and electrical breakdowns resulting in downtimes ranging from days to months. While existing research has identified the higher failure frequency and downtimes between LMICs (Nigeria, Botswana) compared to high‐income countries (HICs, the UK), there has been a need for additional data and study particularly relating to multileaf collimators (MLCs). Materials and methods This study presents for the first time the analysis of data gathered through a dedicated survey and workshop including participants from 14 Indonesian hospitals, representing a total of 19 LINACs. We show the pathways to failure of radiotherapy LINACs and frequency of breakdowns with a focus on the MLC subsystem. Results This dataset shows that LINACs throughout Indonesia are out of operation for seven times longer than HICs, and the mean time between failures of a LINAC in Indonesia is 341.58 h or about 14 days. Furthermore, of the LINACs with an MLC fitted, % of all mechanical faults are due to the MLC, and % of cases requiring a replacement component are related to the MLC. Conclusion These results highlight the pressing need to improve robustness of RT technology for use in LMICs, highlighting the MLC as a particularly problematic component. This work motivates a reassessment of the current generation of RT LINACs and demonstrates the need for dedicated efforts toward a future where cancer treatment technology is robust for use in all environments where it is needed.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Failure modes and downtime of radiotherapy LINACs and multileaf collimators in Indonesia

Pawiro

Kasim

et al. 2022

J Applied Clin Med Phys

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“…Визначити ступінь варіабельності процесів генерації, споживання та накопичення енергії в системі розосередженої генерації та дослідити їх еволюцію можна шляхом оцінки розподілу ймовірностей параметрів системи [22][23][24]. Для вирішення цього завдання використовують ентропійний аналіз, що базується на використанні різних видів ентропій [25][26][27]…”

Section: Iunclassified

The First Selective Entropy as a Function of the State of a Scattered Generation System

Klen¹

2021

Microsyst., Electron. & Acoust.

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In the given paper, it is proposed to use the first selective entropy as a parameter that characterizes the variability of energy generation, consumption and storage processes in distributed generation systems with renewable energy sources, for short-term forecasting to ensure efficient operation of such systems. As an example, the first selective entropy of the power at the output of solar panels is determined, considering other environmental parameters unchanged. The method of calculation of the first sample entropy of the "ideal" daily curve of solar radiation power is given. The ideal daily curve of solar radiation for May 2, 2019 for the city of Zagreb, Republic of Croatia is given. The values of the first selective entropy of the ideal and real solar radiation power curves depending on the number of partition subintervals are given. The schedule of change of power at the output of solar panels for the week from April 27 to May 3, 2019, taken from LARES laboratory, Zagreb, Croatia, is given. The values of the first selective entropy at the output of the solar panels depending on the number of subintervals of the partition are given. The "imperfection" of the power curve at the output of solar panels leads to a decrease in the first selective entropy, which indicates an increase in the variability of the energy generation process. To correct the real power distribution at the output of solar panels and bring it closer to the ideal, it is necessary to use an electric energy storage device with an entropy equal to the modulus of entropy of solar panels, but taken with the opposite sign. The values of the first sample power entropy at the output of solar panels for the week are calculated and their change is shown on the figure. Using Newton's linear interpolation, the values of the first selective entropy for the day 8 and day 2 were predicted. The prediction error of the first selective entropy for the 8th day is 4%, and for the 2nd day - 7%. In the case of significant data deviations, the prediction error increases almost 2 times, but to reduce the magnitude of the prediction error can be performed sequentially with a correction on each prediction interval. It is shown that the implementation of predictive control of the distributed generation system using the first selective entropy, as an integral characteristic of the system state, allows to estimate and compare random processes of energy generation, consumption and accumulation, without finding the laws of their distribution.

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“…The specific domains used in this article are first manufacturability, which is defined as ''the capability to produce the product in a robust and efficient way to meet the design specifications for functions and reliability of the product'' (Bralla, 2004). Second, the reliability which is presented as ''the probability that the system will adequately perform its intended function for a specified interval of a time'' (Grishko et al, 2017).…”

Section: State Of the Artmentioning

confidence: 99%

Integrating model-based system engineering with set-based concurrent engineering principles for reliability and manufacturability analysis of mechatronic products

Borchani

Hammadi

Yahia

et al. 2018

Concurrent Engineering

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The point-based approach consists of committing a set of requirements and a single design solution from the design space. This approach is time-consuming and often leads to deadline excess when developing a new complex system such as mechatronic systems. In fact, this approach could generate iterative loops between engineers in the downstream design stage to evaluate the manufacturability and the quality of the developed system. To overcome this issue, introducing a model-based system engineering (MBSE) approach in the upstream design stage hinged on set-based concurrent engineering (SBCE) principles is a good solution to diminish the exchange loops between engineers and to enhance efficiency in the design process. This approach consists in evaluating a large set of system solutions, then gradually narrowing these solutions until converging to a limited set of optimized solutions. In this article, a novel approach entitled ''Model based for reliability and manufacturability analysis (MBRMA)'' and based on model-based system engineering and set-based concurrent engineering in the preliminary design phases is used to filter out weak or costly solutions over time and to assess system engineer when adopting trade-off analysis. First, customer requirements, functional and structural aspect of the system are defined using SysML diagrams. Next, the application of the algorithm allows narrowing the design space, and finally, a trade-off analysis is carried out to select the best system architecture. The first contribution of this article is the creation of novel stereotypes of composition and allocation flows in a profile diagram between functions and alternative solutions. The second contribution is the implementation of an algorithm to analyze system robustness and to converge on the final set of optimized solutions. To test this newly developed model ''model based for reliability and manufacturability analysis (MBRMA),'' a case study of an air conditioning electrical compressor is considered to illustrate the various stages of this concurrent engineering approach.

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Reliability analysis of complex systems based on the probability dynamics of subsystem failures and deviation of parameters

Cited by 16 publications

References 5 publications

Failure modes and downtime of radiotherapy LINACs and multileaf collimators in Indonesia

Failure modes and downtime of radiotherapy LINACs and multileaf collimators in Indonesia

The First Selective Entropy as a Function of the State of a Scattered Generation System

Integrating model-based system engineering with set-based concurrent engineering principles for reliability and manufacturability analysis of mechatronic products

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