• Journal of the Korean Society of Safety
• /
• v.20 no.4 s.72
• /
• pp.20-28
• /
• 2005

In this paper, the methodology for the reliability estimation of buried pipeline with longitudinal gouges and dent is presented and the limit state of buried pipeline is formulated by failure assessment diagram(FAD). The reliability of buried pipeline with defects has been estimated by using a theory of failure probability. The failure probability is calculated by using the FORM(first order reliability method) and Monte Carlo simulation. The results out of two procedures have been compared each other. It is found that the FORM and Monte Carlo simulation give similar results for varying boundary conditions and various random variables. Furthermore, it is also recognized that the failure probability increases with increasing of dent depth, gouge depth, gouge length, operating pressure, pipe outside radius and decreasing the wall thickness. And it is found that the analysis by using the failure assessment diagram gives highly conservative results than those by using the theory of failure probability.

• Journal of the Korean Society of Safety
• /
• v.27 no.3
• /
• pp.111-116
• /
• 2012

This study is about the quantitative safety assessment of hydrogen station in Korea operating with on-site type. This was written by background information that before qualitative safety assessment to write. For the qualitative safety assessment method, the study used FMEA(failure mode & effect analysis) and HAZOP(hazard & operability), and adopted the FTA(fault tree analysis) as the quantitative safety assessment method. To write the FTA, we wrote FT by Top event that hydrogen leakage can be called most serious accident of hydrogen station. Each base event collect reliability data by reliability data handbook, THERP-HRA and estimation of the engineering. Assessment looked at the high frequency and the possible risk through Gate, Importance, m.cutsets analysis.

• 제어로봇시스템학회:학술대회논문집
• /
• 2001.10a
• /
• pp.40.2-40
• /
• 2001

The protection system of the system communication, nuclear reactor and chemical reactor are representative of reliable system. This reliable system must be designed based on reliability as well as concept of safety, which is a failed system go a way of safe. Reliable system is composed of part of data acquisition, calculator, communication with redundancy, and a voter is important factor of reliability. Because it is serially connected. This paper presents a Design and Analysis of a Voting Mechanism considering Safety for reliable system Using EPLD. In the case of digital implementation a coincidence logic (voter) of reliable system, it needs CPU and memory, so increase a number of units. Therefore the failure rate and cost are increased on contrary when it is designed EPLD or FPGA.

• Proceedings of the Korean Reliability Society Conference
• /
• 2001.06a
• /
• pp.376-383
• /
• 2001

This study reviewed the national standards for risk management to judge whether they are suitable for a product safety management program. Among the standards issued from Australia, New Zealand, Canada, Japan, and UK, the risk management guideline (AS/NZS 4360: 2000) issued jointly from both Australia and New Zealand have better features of product safety management program such as a broad definition of risk concept including opportunities of loss and gain, stepwise composition of processes applicable iteratively, and integrable composition of processes for the existing other management practice. Comparing the three product safety management programs suggested by several authors yielded common features of product safety management program model: (1) organization for product safety, (2) risk identification, (3) risk evaluation, (4) risk treatment, (5) monitoring/communication, and (6) documentation. All of these activities can be performed within risk management framework.

• Journal of Applied Reliability
• /
• v.1 no.2
• /
• pp.109-120
• /
• 2001

This study reviewed the national standards for risk management to judge whether they are suitable for a product safety management program. Among the standards issued from Australia, New Zealand, Canada, Japan, and UK, the risk management guideline (AS/NZS 4360: 2000) issued jointly from both Australia and New Zealand have better features for product safety management program than any other risk management standards in view point of broad definition of risk concept including opportunities of loss and gain, stepwise composition of management processes applicable iteratively, and integrable form of structure addible to existing management practice. Comparing the three product safety management programs suggested by several authors yielded common features of product safety management program model: (1) organization for product safety, (2) risk identification, (3) risk evaluation, (4) risk treatment, (5) monitoring/communication, and (6) documentation. All of these activities can be performed within risk management framework proposed by AS/NZS 4360.

• Proceedings of the KSR Conference
• /
• 2011.10a
• /
• pp.188-194
• /
• 2011

The purpose of this paper is to explain the implementation method in order to enhance stability and reliability of embedded system. In this research, Texas Instrument (TI)'s TMS570 MCU(Micro Controller Unit) is used to satisfy the standard of stability that is IEC 61508. IEC 61508 suggest SIL(Safety Integrity Level) from 1 to 4 and TMS570 is satisfied SIL3. Also, TMS570 can provide several stability functions can be used in realtime system. To use such functions, this paper suggest the solution about the defect that can be used in realtime system. In basic way TMR(Triple Modular Redundancy) suggested in addition to explain about the way to improve safety and reliability. Also this paper will suggest the method that reinforce the stability of calculation by using multiplex voter and memory.

• Proceedings of the KIEE Conference
• /
• 2000.07d
• /
• pp.2557-2560
• /
• 2000

The protection system of the nuclear reactor and chemical reactor are representative of PPC(Plant Protection Controller). This PPC must be designed based on reliability as well as concept of safety, which is a failed system go a way of safe. PPC is consist of part of data acquisition, calculator, communication with redundancy, and a voter is important factor of reliability. Because it is serial connected. This paper presents a Design and Analysis of a Voting Mechanism considering Safety for NMR PPC Using EPLD. In the case of digital implementation a coincidence logic(voter) of PPC, it needs CPU and memory, so increase a number of units. Therefore the failure rate and cost is increased. On the contrary when it is designed EPLD or FPGA.

• Journal of Korean Society for Quality Management
• /
• v.41 no.1
• /
• pp.135-148
• /
• 2013

Purpose: This paper presents a method to evaluate the stockpile reliability of propelling charge for performance and storage safety with storage time. Methods: We consider a performance failure level is the amount of muzzle velocity drop which is the maximum allowed standard deviation multiplied by 6. The lifetime for performance is estimated by non-linear regression analysis. The state failure level is assumed that the content of stabilizer is below 0.2%. Because the degradation of stabilizer with storage time has both distribution of state and distribution of lifetime, it must be evaluated by stochastic process method such as gamma process. Results: It is estimated that the lifetime for performance is 59 years. The state distribution at each storage time can be shown from probability density function of degradation. It is estimated that the average lifetime as $B_{50}$ life is 33 years from cumulative failure distribution function curve. Conclusion: The lifetime for storage safety is shorter than for performance and we must consider both the lifetime for storage safety and the lifetime performance because of variation of degradation rate.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2009.10a
• /
• pp.259-262
• /
• 2009

This paper in order to reduce the electric disaster damage which is caused by with electric equipment of traditional market developed the electric safety monitoring system which is suitable in traditional market. With for this did the actual condition investigation about electrical equipment of traditional market and we constructed Test-bed for testing reliability of electric safety monitoring system. Also experiment led in Test-bed and confirmed a stability. This paper following will be used with the data for the reliability security of the electric safe system operation which follows in the traditional market actual proof equipment construction which will be advanced.

• Journal of Hydrogen and New Energy
• /
• v.17 no.3
• /
• pp.272-278
• /
• 2006

This study is quantitatively assessing of safety about dispenser of hydrogen station because it is hydrogen energy to efficient safety use. The large leakage of hydrogen gas is the most important accident among others occurrence possibility in hydrogen station. It had written FT by top event and calculated unavailability, m-cutsets, leakage frequency, etc with FTA after each base event collect reliability data by reliability data handbook, THERP-HRA and estimation of the engineering.