• Tuberculosis and Respiratory Diseases
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• v.83 no.4
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• pp.268-275
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• 2020

Background: It is not evident that the attributable risk of smoking on mortality in Korea has decreased. We investigated the impact of smoking on all-cause mortality and estimated the attributable risk of smoking in Korean adults. Methods: Those aged ≥20 years with smoking history in the Korean National Health and Nutrition Examination Surveys (KNHANES) 2007-2015 were enrolled. We categorized the participants into three groups as follows: never smoker, <20 pack-years (PY) smokers, and ≥20 PY smokers. We applied inverse probability weighting using propensity scores to control various confounders between the groups. All-cause mortality risks were compared between the groups using the Kaplan-Meier log-rank test. The effects of smoking-attributable risks (ARs) on mortality were also calculated. Results: A total of 50,458 participants were included. Among them, 19,334 (38.3%) were smokers and 31,124 (61.7%) were never smokers. Those with a smoking history of 20 PY or more (≥20 PY smokers), those with a smoking history of less than 20 PY (<20 PY smokers), and never smokers were 18.1%, 20.2%, and 61.7%, respectively, of the study population. Smokers had a higher risk of all-cause mortality compared to never smokers (log-rank test p<0.01). The ARs of smoking were 21.8% (95% confidence interval [CI], 5.7%-37.9%) and 9.0% (95% CI, 6.1%-12.0%) in males and females, respectively. ARs decreased from 24.2% to 19.5% in males and from 9.5% to 4.1% in females between 2007-2010 and 2011-2015. Conclusion: Our study using KNHANES IV-VI data demonstrated that smoking increased the risk of all-cause mortality in a dose-response manner and the ARs of smoking on mortality were 21.8% in males and 9.0% in females during 2007-2015. This suggests that the ARs of smoking on mortality have decreased since around 2010.

• Journal of Fisheries and Marine Sciences Education
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• v.25 no.3
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• pp.716-723
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• 2013

The postal or group questionnaire survey was conducted to inquire into the cause of collision between fishing vessel and non-fishing vessel targeting fishing vessel personnel(FVP), non-NFVP and a person involved in a marine accident. As a result, we could verify the root cause of collision, a negligence of lookout which noted overwork for FVP and careless for non-FVP. The cause of collision by inappropriate avoid action was poor communications for FVP and non-FVP. To reduce collision, we need to be trained to take a sharp lookout, a radio communication by VHF and the collision avoidance actions by early and substantial action to keep well clear. The results are expected to contribute for the reduction of collision and victims.

• Journal of the Korean Statistical Society
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• v.29 no.3
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• pp.319-336
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• 2000

A mixed model with a white noise process and an IMA(0,1,1) process is considered as a process model. It is assumed that the process is a white noise in the absence of a special cause and the process changes to an IMA(0,1,1) due to a special cause. One useful scheme in measuring the process level is to use the variable measurement interval (VMI) between measurement times according to the value of the previous chart statistic. The advantage of the VMI scheme is to measure the process level infrequently when in control to save the measurement cost and to measure frequently when out of control to save the off-target cost. This paper considers the VMI scheme in order to detect changes in the process model from a white noise to an IMA(0,1,1). The VMI scheme is shown to be effective compared to the standard fixed measurement interval (FMI) scheme in both statistical and economic contexts.

• Computers and Concrete
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• v.9 no.2
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• pp.99-118
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• 2012

Marine Structures are very costly and need a continuous inspection and maintenance routine. The most effective way to control the structural health is the application of an expert system that can evaluate the importance of any distress on the structure and provide a maintenance program. An extensive literature review, interviews with expert supervisors and a national survey are used to build a decision support system for concrete structures in sea environment. Decision trees are the main rules in this system. The system input is inspection information and the system output is the main cause(s) of distress(es) and the best repair method(s). Economic condition, severity of distress, distress situation, and new technologies and the most repeated classical methods are considered to choose the best repair method. A case study demonstrates the application of the developed decision support system for a type of marine structure.

• Journal of Korean Society of Water and Wastewater
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• v.10 no.1
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• pp.96-111
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• 1996

The failure of water pipelines is progressed by several compound factors and the collection and analysis of data about pipeline failure are inevitable for effective pipeline rehabilitation. Data analysis of pipeline failure was already performed in USA and Europe. Based on such phenomena, failure characteristics about metropolitan pipelines in Korea were analyzed: The conclusions of this study are as followings. 1. The failure cause of pipelines can be classified into natural cause and artificial cause. Artificial cause is 32% of total causes, so artificial failure as several constructions happens frequently in Korea. Although the failure by old pipe is greatest of any other causes m classtfied cause, failure cause is not classified in detail now. 2. The damaged part of pipelines is affected by cities, distribution system inventory, bedding conditions, and so on. In this study, the failure of pipeline body(67%) is greater than the failure of pipeline joint(33%) in natural failure. 3. In regard to pipe materials, failure rate of DCIP(0.8456), PEP(0.7288), and GSP(0.6643) is greater than that of CIP(0.3985) and CWSP(0.2348). 4. Usually, faIlure rate is increased in proportion to diameter of pipeline. In this study, CIP, DCIP, and CWSP have clear trends. But the trends of PEP is reverse, the case of GSP, HP is obscure due to data shortage. 5. There are no direct relationships between burial age and failure rate of pipelines. 6. Annual breaks and winter(Nov.~Feb.) breaks of pipelines are investigated. As a result, WInter breaks to annual breaks of CIP is 51.3%(Seoul), 51.1%(Taegu),38.7%(Pusan). This phenomena have direct correlation with average winter temp. of cities.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.39 no.2
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• pp.129-137
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• 2016

To identify the cause of the error and maintain the health of system, an administrator usually analyzes event log data since it contains useful information to infer the cause of the error. However, because today's systems are huge and complex, it is almost impossible for administrators to manually analyze event log files to identify the cause of an error. In particular, as OpenStack, which is being widely used as cloud management system, operates with various service modules being linked to multiple servers, it is hard to access each node and analyze event log messages for each service module in the case of an error. For this, in this paper, we propose a novel message-based log analysis method that enables the administrator to find the cause of an error quickly. Specifically, the proposed method 1) consolidates event log data generated from system level and application service level, 2) clusters the consolidated data based on messages, and 3) analyzes interrelations among message groups in order to promptly identify the cause of a system error. This study has great significance in the following three aspects. First, the root cause of the error can be identified by collecting event logs of both system level and application service level and analyzing interrelations among the logs. Second, administrators do not need to classify messages for training since unsupervised learning of event log messages is applied. Third, using Dynamic Time Warping, an algorithm for measuring similarity of dynamic patterns over time increases accuracy of analysis on patterns generated from distributed system in which time synchronization is not exactly consistent.

• Journal of the Korean Institute of Gas
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• v.4 no.4 s.12
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• pp.65-70
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• 2000

We develop the database program for accident cause analysis which can help to increase domestic safety custom and prevent recurrence of gas accident and analyze accidents easily The program developed in this study consists of two parts. one part uses accident case database applied if than rule, so it finds root causes by inference of some input values. The other uses Root Cause Analysis Map which divided human errors and equipment difficulties and so we get general root cause by reply some proper questions.

• Quality Improvement in Health Care
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• v.11 no.1
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• pp.4-14
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• 2004

Background : To examine the problems involved in writing practice of death certificates, we compared the determination of underlying cause of death for vital statistics using recorded underlying cause of death in issued death statistics. Methods : We collected 688 mortality certificates issue in year of 2,000 from 3 university hospitals. And we also collected vital statistics from ministry of statistics. The causes of death were coded by experienced medical record specialists. And causes of death determined at ministry of statistics for national vital statistics were mapped to causes of death recorded at each death certificates. The rate that underlying causes of death for vital statistics were derived from underlying causes of death recorded at issued death certificates were analysed. Results : 64.5% of underlying cause of death for could be derived from underlying cause of death recorded at issued death certificates, 8.6% derived from intermediate cause of death, and 3.9% derived from direct cause of death. In 23% of cases, underlying cause of death could not be derived using issued death certificates. The rate that underlying cause of death for vital statistics could be derived from underlying cause of death recorded at death certificates was different between 3 university hospitals. And the rate was also different between death certificates and postmortem certificates. We classified the causes of death using 21 major categories. The rate was different between diseases or conditions that caused death too. Conclusion : When we examined the correctness of death certificate writing practice using above methods, correctness of writing could not be told as satisfactory. There was difference in correctness of writing between hospitals, between death certificates and postmortem certificates, and between diseases and conditions that caused death. With this results, we suggested some strategy to improve the correctness of death certificate writing practice.

• Journal of the Korean Institute of Gas
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• v.18 no.4
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• pp.86-94
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• 2014

To develop a Root Cause Analysis Map which determines the cause of the accident in chemical laboratory, The Root Cause Analysis(RCA) Map for the laboratory areas was sketched from Phase 1 of the accident element to Phase 3 of the accident element, based on the RCA Map which is applied in the petrochemical industry. On the basis of laboratory RCA Map which was classified by using such method. The root causes of the 211 accident cases in laboratories were classified from Phase 4 to Phase 5 by the Cause Factor Charting technique and The cause of the accident data were inputted to EXCEL program. After that, The causes of the accident data were sorted and classified by type and each step. So 'Approximate Primary RCA Map Draft' was written. In addition, it was reaffirmed whether the root causes of 211 accidents of laboratory were appropriate to 'Primary RCA Map Draft'. By complementing the cause which was expected to cause future accidents, the RCA Map for chemical laboratories was developed. Based on 'RCA Map' proposed in this study, the causes of accidents were analysed management systems 35%, monitoring 12.2%, Human Factor Eng. 15.1% and education training 12.1% by the size of the frequency from Phase 1 to Phase 5.

• 한국방재학회:학술대회논문집
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• 2007.02a
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• pp.94-97
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• 2007

This study aims to find the characteristics of damage and states of natural disasters at Gimhae, Gyeongsangnam-do from 1985 to 2004. Using the data of Statistical yearbook of calamities issued by the National Emergency Management Agency and Annual Climatological Report issued by the Korea Meteorological Administration. we have analyzed the cause, elements, and vulnerable regions for natural disasters. Major causes of natural disaster at Gimhae are four, such as a heavy rain, heavy rain typhoon, typhoon, storm snow, and storm. The cause of disaster recorded the most amount of damage is typhoon. The areas of Hallim-myeon, Sangdong-myeon, and Saengnim-myeon are classified the vulnerable region for the natural disasters in Gimhae. Therefore, it seems necessary to build natural disaster mitigation plan each cause of disaster to control water resources and to reduce damage for these areas.