• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.66 no.6
• /
• pp.995-1000
• /
• 2017

In this paper, we present an electrical arc detection algorithm using the mash-up analysis technique which is the core technology for the autonomous electrical safety management system(AESMS) of the multi-unit dwellings. The mash-up analysis technique analyzes the voltage, load current, zero phase current data simultaneously to judge arc faults. In order to develop the arc fault detection algorithm, the characteristics of series arc and parallel arc were analyzed. Also, we propose the mash-up analysis technique that analyzes waveforms of voltage, load current, and zero phase current at the same time. The arc fault detection algorithm was developed using the mash-up analysis technique. The developed algorithm can prevent electrical disasters in an effective way through accident prediction, and it will be used as a basic technology to introduce an autonomous electrical safety management system.

• Journal of the Korean Society of Safety
• /
• v.36 no.3
• /
• pp.50-59
• /
• 2021

The main purpose of accident analysis is to identify the causal factors and the mechanisms of those factors leading to the accident. However, current accident analysis techniques focus only on finding the factors related to the accident without providing more insightful results, such as structures or mechanisms. For this reason, preventive actions for safety management are concentrated on the elimination of causal factors rather than blocking the connection or chain of accident processes. This greatly reduces the effectiveness of safety management in practice. In the present study, a technique to model the correlational structure of accident risk factors is proposed by using the co-occurrence keyword network analysis technique. To investigate the effectiveness of the proposed technique, a case study involving a portable ladder fall accident is conducted. The results indicate that the proposed technique can construct the correlational structure model of the risk factors of a portable ladder fall accident. This proves the effectiveness of the proposed technique in modeling the correlational structure of accident risk factors.

• Nuclear Engineering and Technology
• /
• v.51 no.5
• /
• pp.1289-1296
• /
• 2019

Non-functional requirements plays a critical role in designing variety of applications domain ranges from safety-critical systems to simple gaming applications. Performance is one of the crucial non-functional requirement, especially in control and safety systems, that validates the design. System risk can be quantified as a product of probability of system failure and severity of its impact. In this paper, we devise a technique to do the performance analysis of safety critical and control systems and to estimate performance based risk factor. The technique elaborates Petri nets to estimate performability to ensure system dependability requirements. We illustrate the technique on a case study of Nuclear Power Plant system. The technique has been validated on 17 safety critical and control systems of Nuclear Power Plant.

• Journal of the Korean Society of Safety
• /
• v.29 no.3
• /
• pp.79-84
• /
• 2014

Human error is one of the major contributors to the accidents. A lot of risk assessment techniques have been developed for prevention of accidents. Nevertheless, most of them were interested in physical factors, because quantitative evaluation of human errors was difficult quantitatively. According to lack of risk assessment techniques about human errors, most of industrial risk assessment for human errors were based on data of accident analysis. In order to develop an effective countermeasure to reduce the risk caused by human errors, a systematic analysis is needed. Generally, risk assessment system is composed of 5 step(classification of work activity, identification of hazards, risk estimation, evaluation and improvement). This study aimed to develop a risk identification technique for human errors that could mainly be applied to industrial fields. In this study, Ergo-HAZOP and Comprehensive Human Error Analysis Technique were used for developing the risk identification technique. In the proposed risk identification technique, Ergo-HAZOP was used for broad-brush risk identification. More critical risks were analysed by Comprehensive Human Error Analysis Technique. In order to verify applicability, the proposed risk identification technique was applied to the work of pile head cutting. As a consequence, extensive hazards were identified and fundamental countermeasures were established. It is expected that much attention would be paid to prevent accidents by human error in industrial fields since safety personnel can easily fint out hazards of human factors if utilizing the proposed risk identification technique.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2002.03a
• /
• pp.643-650
• /
• 2002

The large planar failure has occurred in a rock cut slope of highway construction site in Boeun. This area is considered as unstable since the discontinuities whose orientations are similar to the orientation of the failure plane, are observed in many areas. Therefore, several analysis techniques such as SMR, stereographic analysis, limit equilibrium, numerical analysis, which are commonly used in rock slope stability analysis, are adopted in this area. In order to analyze the stress redistribution and nonlinear displacement caused by cut, which are not obtained in limit equilibrium method, the UDEC and shear strength reduction technique were used in this study Then the factors of safety evaluated by shear strength reduction technique and limit equilibrium were compared. In addition, the factor of safety under fully saturated slope condition was calculated and subsequently, the effect of the reinforcement was evaluated.

• Proceedings of the Korean Nuclear Society Conference
• /
• 1997.05a
• /
• pp.153-158
• /
• 1997

This paper describes a formal safety analysis technique which is demonstrated by performing empirical formal safety analysis with the case study of beamline hutch door Interlock system that is developed by using PLC(Programmable Logic Controller) systems at the Pohang Accelerator Laboratory. In order to perform formal safety analysis, we have built the Z formal specifications representation from user requirement written in ambiguous natural language and target PLC ladder logic, respectively. We have also studied the effective method to express typical PLC timer component by using specific Z formal notation which is supported by temporal history. We present a formal proof technique specifying and verifying that the hazardous states are not introduced into ladder logic in the PLC-based safety critical system.

• Proceedings of the KIEE Conference
• /
• 2011.07a
• /
• pp.2130-2131
• /
• 2011

Electric fire breaks out by various causes such as electric short, overload(over current), leakage current, poor contact, static electricity, insulation deterioration, partial disconnection and etc. In this paper, we studied analysis technique for scientific and systematic judgment for distinction of electricity fire existence and nonexistence, and described about electricity fire cause analysis process for collecting physical evidences. We handled external form analysis, Substance extension analysis, X-ray transmission analysis, cross-section analysis, thermal analysis, chemical structure analysis, surface structure analysis, component analysis, electrical properties analysis, and circuit analysis by analysis technique for electricity fire cause judgment. We expect that analysis technic elevation and correct cause of fire analysis of scene of a fire investigators and analysts through this paper which see help.

• International conference on construction engineering and project management
• /
• 2009.05a
• /
• pp.432-439
• /
• 2009

This research project was carried out to develop the technique to assess quantitatively and rapidly the stability of a tunnel by using the measured displacement at the tunnel construction site under excavation. To achieve this purpose, a critical strain concept was introduced and applied to an assessment of a tunnel under construction. The new technique calculates numerically the strains of the surrounding ground by using the measured displacements during excavation. A numerical practical system was developed based on the proposed analysis technique in this study. The feasibility of the developed analysis module was verified by incorporating the analysis results obtained by commercial programs into the developed analysis module. To verify the feasibility of the developed analysis module, analysis results of models both elastic and elasto-plastic grounds were investigated for the circular tunnel design. Then the measured displacements obtained in the field are utilized practically to assess the safety of tunnels using critical strain concept. It was verified that stress conditions of in-situ ground and ground material properties were accurately assessed by inputting the calculated displacement obtained by commercial program into this module for the elastic ground. However for the elasto-plastic ground, analysis module can reproduce the initial conditions more closely for the soft rock ground than for the weathered soil ground. The stability of tunnels evaluated with two types of strains, that is, the strains obtained by dividing the crown displacement into a tunnel size and the strains obtained by using the analysis module. From this study, it is confirmed that the critical strain concept can be fully adopted within the engineering judgment in practical tunnel problems and the developed module can be used as a reasonable tool for the assessment of the tunnel stability in the field.

• Journal of the Korean Society of Safety
• /
• v.26 no.1
• /
• pp.27-35
• /
• 2011

There are many countermeasures collected by field experts, safety managers with their subjective decisions, without analysis. Subcontractor does not know which one of those can be more defective countermeasures. More weighted countermeasures should be taken for subcontractor's economical aspects. But there are almost no measures with useful weight so that subcontractors can select some as they need more effective even though there are not many measures at construction sites. AHP technique has been introduced into the analysis of counter measures for subcontractor. Countermeasures which car collected from field-experienced safety engineers have been weighed with frequency rate saying how many responders selected. And then, they are analyzed by AHP Technique for making out relative important level of the countermeasures, by each step such as Direct, Indirect, Management level, and policy level, quantitatively. AHP level in the study is composed of two stories, not three stories, in order to make respondents easier when they are asked. At least 15-year-experienced expert are asked for AHP questionnaire.

• Journal of the Ergonomics Society of Korea
• /
• v.23 no.3
• /
• pp.53-72
• /
• 2004

Today we are observing a lot of injuries, casualties, and property losses that are mainly caused by the defects of products. In order to derive safety designs, which minimize the possibility of such product liability-related accidents, we need to take into account the user-product interaction as an important part of the danger factor analysis. Existing risk analysis techniques, however, have some limitations in detecting comprehensive danger factors that are peculiarly involved in human errors and the functional defects of products. Researches on danger factor analysis regarding the user-product interaction have been carried out actively in ergonomics. In this paper, we suggest a novel product risk analysis technique, which is more objective and systematic compared to the previous ones, by combining a modified TAFEI (Task Analysis For Error Identification) technique with SASA (Systematic Approach to Accident Scenario Analysis) technique. By applying this technique to the product design practice in industry, corporations will be able to improve the product safety, consequently strengthening the competitiveness.