scholarly journals Kriteriji za izbiro kakovostnih in zanesljivih UPS-ov v bolnišnicah

2021 ◽  
Author(s):  
Žiga Bobek ◽  
Vojko Matko
Keyword(s):  
Reliability Function ◽  
Power Outage ◽  
Uninterruptible Power Supply ◽  
Mean Time Between Failures ◽  
Time Between Failures ◽  
Operating Temperatures ◽  
Uninterruptible Power ◽  
Reliability Of Operation ◽  
Mean Time ◽  
Selection Of

Uninterruptible Power Supply (UPS) management is one of the important factors in hospitals. With the help of UPSes, vital and critical electrical devices (especially in operating rooms and intensive care units) are not left without power in the event of a power outage. Therefore, when choosing these devices, it is important that they work reliably and that they have the longest possible period of operation. The article describes important criteria in the selection of UPS devices that affect the reliability of operation, which is especially important when updating equipment. The most important standards and methods for evaluating the reliability of operation and the calculation of MTBF (Mean Time Between Failures) in the case of UPS are presented, which indicate when the equipment needs to be replaced. As a result, the reliable functions of the UPS at three operating temperatures are given. We also calculated the values of the reliability function, where we checked the different qualities of the installed elements at two different operating temperatures.

scholarly journals DEGRADATION ANALYSIS OF PROBABILISTIC PARALLEL CHOICE SYSTEMS

2014 ◽  
Vol 21 (03) ◽  
pp. 1450012
Author(s):  
AVINASH SAXENA ◽  
SHRISHA RAO
Keyword(s):  
Complete System ◽  
System Failure ◽  
Time To Failure ◽  
Probabilistic Choice ◽  
Mean Time Between Failures ◽  
System Parameters ◽  
Time Between Failures ◽  
Degradation Analysis ◽  
Mean Time ◽  
Selection Of

Degradation analysis is used to analyze the useful lifetimes of systems, their failure rates, and various other system parameters like mean time to failure (MTTF), mean time between failures (MTBF), and the system failure rate (SFR). In many systems, certain possible parallel paths of execution that have greater chances of success are preferred over others. Thus we introduce here the concept of probabilistic parallel choice. We use binary and n-ary probabilistic choice operators in describing the selections of parallel paths. These binary and n-ary probabilistic choice operators are considered so as to represent the complete system (described as a series-parallel system) in terms of the probabilities of selection of parallel paths and their relevant parameters. Our approach allows us to derive new and generalized formulae for system parameters like MTTF, MTBF, and SFR. We use a generalized exponential distribution, allowing distinct installation times for individual components, and use this model to derive expressions for such system parameters.

Review of Technological Advancements and HSE-Based Safety Model for Deep-Water Human Occupied Vehicles

2014 ◽  
Vol 48 (3) ◽  
pp. 25-42 ◽  
Author(s):  
Narayanaswamy Vedachalam ◽  
Gidugu Ananada Ramadass ◽  
Malayath Aravindakshan Atmanand
Keyword(s):  
Deep Water ◽  
Capital Expenditure ◽  
Mean Time Between Failures ◽  
Safety Integrity Level ◽  
Geological Surveys ◽  
Time Between Failures ◽  
High Resolution Bathymetry ◽  
Safety Systems ◽  
Mean Time ◽  
Safety And Environment

AbstractThis paper reviews the latest advancements in subsea technologies associated with the safety of deep-water human occupied vehicles. Human occupied submersible operations are required for deep-water activities, such as high-resolution bathymetry, biological and geological surveys, search activities, salvage operations, and engineering support for underwater operations. As this involves direct human presence, the system has to be extremely safe and reliable. Based on applicable IEC 61508 Standards for health, safety, and environment (HSE), the safety integrity level requirements for the submersible safety systems are estimated. Safety analyses are done on 10 critical submersible safety systems with the assumption that the submersible is utilized for 10 deep-water missions per year. The results of the analyses are compared with the estimated target HSE requirements, and it is found that, with the present technological maturity and safety-centered design, it is possible to meet the required safety integrity levels. By proper maintenance, it is possible to keep the mean time between failures to more than 9 years. The results presented shall serve as a model for designers to arrive at the required trade-off between the capital expenditure, operating expenditure, and required safety levels.

scholarly journals The Use of Statistical Inference in the Water Supply Network Managing Operation Process

2019 ◽  
Vol 49 (4) ◽  
pp. 221-244
Author(s):  
Izabela Piegdoń
Keyword(s):  
Water Supply ◽  
Time To Failure ◽  
Supply Network ◽  
Water Supply Network ◽  
Time Between Failures ◽  
Operation Process ◽  
Safety And Reliability ◽  
Mean Time ◽  
Operational Data ◽  
Selection Of

Abstract Based on operational data concerning the dates of failure of the water supply network, a mean time to failure was performed. The calculations were performed for the main network, distribution network and water supply connections. The hypothesis about exponential working time between failures was verified using the Pearson test (χ2). The presented analyses provide an attitude of further analyses related to modelling the work of renovation and repair teams, associated with the selection of their appropriate number, and also to ensure the required level of safety and reliability of water supply to the consumers.

scholarly journals A Statistical State Analysis of a Marine Gas Turbine

Actuators ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 54 ◽  
Author(s):  
Suzana Lampreia ◽  
Valter Vairinhos ◽  
Victor Lobo ◽  
José Requeijo
Keyword(s):  
Gas Turbine ◽  
Point Of View ◽  
Operating Conditions ◽  
Environmental Data ◽  
Statistical Point ◽  
Mean Time Between Failures ◽  
Time Between Failures ◽  
Intervention Plan ◽  
Mean Time

This paper describes the analysis, from a statistical point of view, of a maritime gas turbine, under various operating conditions, so as to determine its state. The data used concerns several functioning parameters of the turbines, such as temperatures and vibrations, environmental data, such as surrounding temperature, and past failures or quasi-failures of the equipment. The determination of the Mean Time Between Failures (MTBF) gives a rough estimate of the state of the turbine, but in this paper we show that it can be greatly improved with graphical and statistical analysis of data measured during operation. We apply the Laplace Test and calculate the gas turbine reliability using that data, to define the gas turbine failure tendency. Using these techniques, we can have a better estimate of the turbine’s state, and design a preventive observation, inspection and intervention plan.

Comparison of the Mean Time Between Failures for Two Systems Under Short Tests

2009 ◽  
Vol 58 (4) ◽  
pp. 589-596 ◽  
Author(s):  
Y.H. Michlin ◽  
G.Y. Grabarnik ◽  
E. Leshchenko
Keyword(s):  
Mean Time Between Failures ◽  
Time Between Failures ◽  
Two Systems ◽  
The Mean ◽  
Mean Time

A warranty based bilateral multi-issue negotiation approach

2015 ◽  
Vol 22 (7) ◽  
pp. 1247-1280 ◽  
Author(s):  
Prashant M. Ambad ◽  
Makarand S. Kulkarni
Keyword(s):  
Real Life ◽  
Spare Parts ◽  
Negotiation Process ◽  
Design Stage ◽  
Automated Negotiation ◽  
Content Type ◽  
Mean Time Between Failures ◽  
Time Between Failures ◽  
Target Values ◽  
Mean Time

Purpose – The purpose of this paper is to propose a warranty-based bilateral automated multi-issue negotiation approach. Design/methodology/approach – A methodology for bilateral automated negotiation process is developed considering the targets such as warranty attractiveness, warranty cost, mean time between failures, spare parts cost to the end user over the useful life of the life. The negotiation methodology is explained using different cases of negotiation. The optimization for each negotiation step is carried out using genetic algorithm with elitism strategy. Findings – The result after optimization indicates that the desired target values are achieved and manufacturer obtained desired profit margin. Practical implications – Application of automated negotiation model is illustrated using a real life case of an automobile engine manufacturer. The proposed approach helps the manufacturer of any product to develop a methodology for carrying out the negotiation process. The approach also results into taking warranty-related decisions at the design stage. Originality/value – This paper contributes in proposing a generalized methodology for warranty-based negotiation in which the negotiation is carried out between the manufacturer and the customer.

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