• 한국안전학회지
• /
• 제27권5호
• /
• pp.64-69
• /
• 2012

The concept of SIL is applied in the most of all standards relating to functional system safety. However there are problems for the people to apply SIL to their plants. as these standards don't include sufficient informations. In this regards, this paper will suggest the direction of SIL application and concept based on IEC 61508 and IEC 61511. A Safety Integrity Level(SIL) is the discrete level(one out of possible fours), corresponding to a range of the probability of an E/E/PE (Electric/Electrical/Programmable Electrical) safety-related system satisfactorily performing the specific safety functions under all the stated conditions within a stated period of time. SIL can be divided into the target SIL(or required SIL) and the result SIL. The target SIL is determined by the risk analysis at the analysis phase of safety lifecycle and the result SIL is calculated during SIL verification at the realization phase of safety lifecycle. The target SIL is determined by the risk analysis like LOPA(Layer Of Protection Analysis), Risk Graph, Risk Matrix and the result SIL is calculated by HFT(Hardware Fault Tolerance), SFF(Safe Failure Fraction) and PFDavg(average Probability of dangerous Failure on Demand). SIL is applied to various areas such as process safety, machinery(road vehicles, railway application, rotating equipment, etc), nuclear sector which functional safety is applied. The functional safety is the part of the overall safety relating to the EUC and the EUC control system that depends on the correct functioning of the E/E/PE safety-related systems and other risk reduction measures. SIL is applied only to the functional safety of SIS(Safety Instrumented System) in safety. EUC is the abbreviation of Equipment Under Control and is the equipment, machinery, apparatus or plant used for manufacturing, process, transportation, medical or other activities.

• 디지털융복합연구
• /
• 제17권8호
• /
• pp.105-113
• /
• 2019

본 연구는 원자력 발전소등의 국가 핵심기반시설에 대한 기존의 사이버 보안 위험 모델링 기법을 분석하고 이의 한계점 및 개선방안을 도출하는데 목적이 있다. 연구 대상은 전력 및 원자력 발전소, SCADA등의 국가 핵심기반시설의 사이버 보안 위험 모델링 기법이다. 연구에서는 SCADA, 전력, 원자력 발전의 사이버 보안 위험 모델링 분야의 총 26편에 대한 선행 연구 사례를 분석하고, 이를 정성적 모델링과 정량적 모델링 기법으로 구분하여 각각의 특징과 한계점에 대해 분석하였다. 최근 핵심기반시설은 디지털화 되어 가는 추세이며 Windows등의 운영체제를 사용하는 시스템들로 구성되어 있지만, 상시 운영되어야 하는 요구사항으로 인해, 취약점이 발견되더라도 패치등을 즉각 행할 수가 없는 특징이 있다. 본 연구에서는 이러한 제약사항들을 감안하여 취약점들이 핵심기반시설의 생명주기동안 어떤 특성으로 전파되고 예방 할 수 있는지에 대한 모델링 기법 방안을 제시하고 있다.

• 한국멀티미디어학회논문지
• /
• 제18권11호
• /
• pp.1367-1374
• /
• 2015

In this paper, we propose a model which can prioritize the performance improvement work by analyzing the major risks and their influence, which can cause performance degradation in the system and show an example of a performance improvement using this model. In presentation-tier, as a result of log data analysis before and after the performance improvement of key processes which handle financial transactions, this model brought the CPU utilization and memory enhancement in the performance improvement work of the financial system which was carried out by applying the proposed model. It has been confirmed that the entire end-user can be accommodated. In the web-tier, the available memory increased by 200MB and we were able to improve the server restart(Recycling) that was sustained in the existing system. In the business logic-tier, we have been able to see better figures after performance improvements through the graph which analyzes the log collected with the key performance counters such as CPU%, Batch Requests/sec. In the data-tier, it has been confirmed that CPU usage and standby operation were reduced and the throughput was found to increase.

• 로봇학회논문지
• /
• 제15권4호
• /
• pp.341-349
• /
• 2020

Recently, interest in ground subsidence in urban areas has increased after a large sinkhole occurred near the high-story building area in Jamsil, Seoul, Korea, in 2014. If a massive sinkhole occurs in an urban area, it is crucial to assess its risk rapidly. Access to humans for on-site safety diagnosis may be difficult because of the additional risk of collapse in the disaster area. Generally, inspection using drones equipped with high-speed lidar sensors can be utilized. However, if the sinkhole is created vertically to a depth of 100 m, similar to the sinkhole in Guatemala, the drone cannot be applied because of the wireless communication limit and turbulence inside the sinkhole. In this study, a three-dimensional (3D) scanning system was fabricated and operated using a towed cable in a massive vertical sinkhole to a depth of 200 m. A high-speed lidar sensor was used to obtain a continuous cross-sectional shape at a certain depth. An inertial-measuring unit was applied to compensate for the error owing to the rotation and pendulum movement of the measuring unit. A reconstruction algorithm, including the compensation scheme, was developed. In a vertical hole with a depth of 180 m in the mining area, the fabricated system was applied to scan 0-165 m depth. The reconstructed shape was depicted in a 3D graph.

• 한국안전학회지
• /
• 제21권5호
• /
• pp.60-71
• /
• 2006

In recent years, the most safety studies have been focused on identifying the relationship between safety climate and safe work behavior in accordance with the awareness that prime causes of accidents are organizational, managerial, and human factors rather than pure technical failures across the world. This study focused empirical research aimed at finding out the safety climate factors and examining the relationships of the safety climate and safe work behavior in construction site in Korea, too. A 10 numbers of safety climate factors were adapted from the Mohamed's study(2002) and tested using PLS-GRAPH 3.0 expecting same results as Mohamed' study. And then the relationship between safety climate and safe work behavior was examined. Only two safety climate factors-personal risk appreciation and worker's safety competence-were found and a strong positive relationship between safety climate and safe work behavior was identified in this study. Discussed in details about the results and implications and suggested further studies.

• 한국콘텐츠학회논문지
• /
• 제5권2호
• /
• pp.107-114
• /
• 2005

기업 네트워크 환경 및 인터넷상에서 발생할 수 있는 보안상의 취약점들은 악의를 가진 내외부의 공격자들에게 악용될 가능성이 있다. 이러한 상황은 기업으로 하여금 정보 자산의 유출 및 파괴 등의 물리적인 피해와 더불어 복구를 위한 인력 및 시간의 소요 등 금전적인 손해를 야기시킨다. 이에 정확한 네트워크 보안 위험을 분석하여 이러한 피해의 가능성을 사전에 파악하고, 예방할 수 있는 방안을 마련하여 최대한의 보안성을 확보하여야 한다. 본 고는 이를 해결하기 위한 네트워크의 보안 수준을 측정하고 분석할 수 있는 국내에서의 접근 방법론을 살펴보고, 적절한 평가 절차 및 평가 수행 방법, 점검 항목을 도출한다.

• 한국철도학회논문집
• /
• 제10권2호
• /
• pp.131-136
• /
• 2007

In this paper, the methodology to predict the number of deaths and possible fire propagation scenarios will be described in case of fire on a train in a tunnel. We use a probabilistic analysis method for the evaluation of possibility for each scenario and the deaths tolls are calculated with the help of the passenger evacuation simulation program. The resulting safety of passengers is displayed on a F/N graph, which could be used in part as a guideline to predict the safety level of the tunnel in fire.

• 척추신경추나의학회지
• /
• 제17권2호
• /
• pp.131-139
• /
• 2022

Objectives This study aimed to analyze the medical utilization of low back pain (LBP) patients after back surgery and estimate the medical costs of Korean and Western medicine collaborative treatment, odds ratio, and hazard ratio between the two groups using the 2019 Health Insurance Review and Assessment Service-National Patient Sample (HIRA-NPS-2019). Methods Data management and descriptive analysis, logistic regression, and survival analysis were conducted for defining and estimating the LBP patients after back surgery in the NPS 2019 dataset. Results A total of 216,424 patients out of 991,189 were identified as having LBP. Among the patients with LBP, 1,734 were treated with surgery while 214,690 were not. Among those who had surgery, 937 were treated with conventional treatments only and 797 underwent Korean medicine treatments. The odds ratio of the logistic regression analysis was 0.7129, suggesting that Korean medical treatment experience group had a 28.7% lower risk of reoperation than the Western medical treatments only group. The hazard ratio of the survival analysis was 0.9145; thus, the risk probability of reoperation was estimated to be approximately 8.55% lower. The 50% risk of reoperation was 69 days (0.5044) for the conventional group, and 97 days (0.5008) for the Korean medical group in the survival analysis using the Kaplan-Meier graph. Conclusions These results could be utilized in future studies in conducting economic evaluation for estimating cost-effectiveness of Western medicine and Korean medicine treatment compared to Western medicine alone in LBP patients after back surgery in a South Korean perspective. mended and should be applied while taking the necessary precautions.

• Journal of the Korean Wood Science and Technology
• /
• 제51권4호
• /
• pp.295-308
• /
• 2023

This study applied a real-time IoT (Internet of Things) environmental monitoring system to wooden cultural heritages (WCHs) located in suburbs and forests in Korea. It automated the graphs of seasonal Temperature (T) and relative humidity (RH) changes inside the heritage structures and seasonal Performance Index (PI) values. While utilizing line graphs of the existing T and RH change trends and a bar graph expressing the PI values, this study examined the current status of the conservation environment inside the WCHs throughout the year and its diagnosis. Consequently, at higher latitudes, the organic cultural heritage repeatedly experienced large T fluctuations, and the risk of physical and chemical degradation of the materials was greater. However, the RH showed significant seasonal differences, even within the same latitude, indicating that the impact of latitude was not significant. Therefore, the staff in charge must manage RH by considering the surrounding environmental conditions and adjusting the internal environment of the structures. The PI values for the year-round T and RH inside the heritages were confirmed to only be a maximum of approximately 60% of the environmental suitability for conservation throughout the year, depending on the season. The relationship between the germination and growth potential period of xerophilic fungi and the monthly internal temperature and humidity in five heritages located at different latitudes was analyzed. As a result, we could thus determine that four particular months of the year (June-September) represent the periods with the highest risk of damage from xerophilic fungi in the country, regardless of latitude.

• 대한교통학회지
• /
• 제35권2호
• /
• pp.160-168
• /
• 2017

지난 10년 간 졸음운전은 전체 고속도로 사고건수의 약 23%로 교통사고 사망원인 중 가장 높은 비중을 차지하고 있다. 과속, 주시태만 등 운전자 과실이 주요원인인 일반적인 사고유형과 달리, 졸음운전은 졸음이라는 불가항력적 원인에 의해 발생한다는 점에서 타 사고유형과 차별화된 접근이 요구된다. 그 동안의 졸음운전 감소대책은 일반적인 교통사고 대책과 마찬가지로 사고다발지점과 같은 특정지점(spot)에 집중하였으나, 도로특성(해당구간의 화물차 비율 등) 또는 시간특성(누적주행시간에 따른 위험 운전행동 증가 등)을 고려한 감소대책이 필요함에 따라, 본 연구에서는 시 공간적으로 확대한 구간(link) 개념을 도입하였다. 고속도로 졸음운전 위험구간 분석을 위해 화물차 디지털 운행기록계(digital tacho graph: DTG) 자료를 활용하였으며, 이를 바탕으로 졸음운전 위험구간을 산정하였다. 위험 행동지표와 사고 발생건수 간의 상관 분석을 위해 음이항 회귀모형(negative binomial regression)을 통한 졸음사고 예측모형을 추정하였으며 모형의 결과 값을 바탕으로 경험적 베이즈(empirical Bayes: EB) 추정치와 구간별 잠재적 안전개선 지수(potential for safety improvement: PSI)를 산출하여 졸음운전 위험 구간을 선정하였다. 졸음사고 모형 추정 결과, 연평균 일교통량, 화물차 비율, DTG 수집 자료건수, 평균 과속비율(20km/h 초과), 평균 급감속비율 및 평균 급차로변경비율이 늘어날 경우 졸음운전 사고건수 역시 증가하는 것으로 분석되었다.