• 대한안전경영과학회지
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• 제11권1호
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• pp.121-130
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• 2009

This paper considers a six sigma project for reducing the cost copper of the cable materials in a electric wire company. The project follows a disciplined process of five macro phases: define, measure, analyze, improve, and control (DMAIC). A process map is used to identify process input variables. Three key process input variables are selected by using an input variables are selected by using an input variable evaluation table: large cable, plating, and a twisted pair. DOE is utilized for finding the optimal process conditions of the three key process input variables. The implementing result of this six sigma project is enable for reducing of the 2.8% copper materials.

• 대한안전경영과학회지
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• 제22권4호
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• pp.9-15
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• 2020

As of 2018, total yield of lettuce and strawberry amounted to 93,543 tons (representing 1.0 percent) and 183,639 tons (2.0 percent), respectively, among total yields worth 9,185,889 tons in South Korea. Lettuce is affected by a combination of numerous elements such as varieties, cultivation methods and pests during each growth phase (Lee et al., 1999). It is mainly cultivated in spring and fall. Especially due to respiration rate after harvest leading to reduced quality and poor storage, maintaining annual supply is unavailable (Jang et al., 2018). With the distribution of new varieties, forcing culture and indoor insulated facilities for plant cultivation during winter, strawberries are produced every year except for late summer and early fall. Due to active respiration, transpiration, soft flesh and high water content, the fruit is vulnerable to go bad and got rotten compared to other fruits. Furthermore, it is difficult to maintain freshness due to the possibility of softening, discoloration and fungi (Lee et al., 2012). In this regard, developing improved storage and package techniques is needed to ensure maintaining quality and safety even just two to three days after harvest. In order to ensure improved quality and safety of strawberries and lettuce after harvest, the present study applied a modified atmosphere packaging (MAP) technology (Mostofi et. al., 2008). Going forward, it compared the quality and safety of the two products while being stored in a way that put them in an MAP-applied container and a plastic container at room temperature and 4 degree Celsius.

• 한국안전학회지
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• 제34권4호
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• pp.111-118
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• 2019

Accidents occurring due to natural disasters in chemical process facilities where technologies are concentrated can cause secondary damage. The concept of the relationship between natural disasters and highly intensive technologies has evolved into the Natech (Natural Hazards Triggered Technological Disaster) research. Currently, the number of earthquakes is increasing all over the Korean peninsula. To assess the risk of Natech when an earthquake has occurred in South Korea, the Rapid Natech Risk Assessment Tool (RAPID-N) developed by the European Commission's Joint Research Center (EC JRC) was used in the present study. The RAPID-N can be used for Natech risk assessment based on mapping and can be utilized for sufficient preparation for reduction of the effects of Natech accidents. A total of 261 chemical facilities actually existing in Pohang were initially analyzed to select eight facilities and the Pohang earthquake that occurred in 2017 was implemented in the RAPID-N utilizing the shake map. High risk areas were selected through Natech risk assessments for the selected eight work places and countermeasures for the areas were suggested. High risk areas exist depending on the location, since the damage influence ranges could be overlapped and each chemical facility has an independent probability of Natech. Therefore, studies on Natech emergency plans and emergency evacuation routes should be actively conducted considering such high risk areas. The present study was conducted to demonstrate the feasibility of Natech risk assessment in South Korea through the RAPID-N. These findings can be used as a reference material to lay a foundation for Natech risk assessment and related policies in South Korea.

• Proceedings of the National Institute of Ecology of the Republic of Korea
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• 제1권1호
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• pp.74-82
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• 2020

Predictions of suitable habitat areas can provide important information pertaining to the risk assessment and management of alien plants at early stage of their establishment. Here, we predict the invasion potential of Muhlenbergia capillaris (pink muhly) in South Korea using five bioclimatic variables. We adopt four models (generalized linear model, generalized additive model, random forest (RF), and artificial neural network) for projection based on 630 presence and 600 pseudo-absence data points. The RF model yielded the highest performance. The presence probability of M. capillaris was highest within an annual temperature range of 12 to 24℃ and with precipitation from 800 to 1,300 mm. The occurrence of M. capillaris was positively associated with the precipitation of the driest quarter. The projection map showed that suitable areas for M. capillaris are mainly concentrated in the southern coastal regions of South Korea, where temperatures and precipitation are higher than in other regions, especially in the winter season. We can conclude that M. capillaris is not considered to be invasive based on a habitat suitability map. However, there is a possibility that rising temperatures and increasing precipitation levels in winter can accelerate the expansion of this plant on the Korean Peninsula.

• Nuclear Engineering and Technology
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• 제37권6호
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• pp.575-586
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• 2005

In a CANDU (CANada Deuterium Uranium) reactor, fuel channel integrity depends on the coolability of the moderator as an ultimate heat sink under transient conditions such as a loss of coolant accident (LOCA) with coincident loss of emergency core cooling (LOECC), as well as normal operating conditions. This study presents assessments of moderator thermal-hydraulic characteristics in the normal operating conditions and one transient condition for CANDU-6 reactors, using a general purpose three-dimensional computational fluid dynamics code. First, an optimized calculation scheme is obtained by many-sided comparisons of the predicted results with the related experimental data, and by evaluating the fluid flow and temperature distributions. Then, using the optimized scheme, analyses of real CANDU-6 in normal operating conditions and the transition condition have been performed. The present model successfully predicted the experimental results and also reasonably assessed the thermal-hydraulic characteristics of a real CANDU-6 with 380 fuel channels. A flow regime map with major parameters representing the flow pattern inside a calandria vessel has also proposed to be used as operational and/or regulatory guidelines.

• Nuclear Engineering and Technology
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• 제55권1호
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• pp.131-143
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• 2023

Constitutive equations in a nuclear reactor safety analysis code are mostly empirical correlations developed from experiments, which always accompany uncertainties. The accuracy of the code can be improved by modifying the constitutive equations fitting wider range of data with less uncertainty. Thus, the sensitivity of the code with respect to the constitutive equations is evaluated quantitatively in the paper to understand the room for improvement of the code. A new methodology is proposed which first starts by dividing the thermal hydraulic conditions into multiple sub-regimes using self-organizing map (SOM) clustering method. The sensitivity analysis is then conducted by multiplying an arbitrary set of coefficients to the constitutive equations for each sub-divided thermal-hydraulic regime with SOM to observe how the code accuracy varies. The randomly chosen multiplier coefficient represents the uncertainty of the constitutive equations. Furthermore, the set with the smallest error with the selected experimental data can be obtained and can provide insight which direction should the constitutive equations be modified to improve the code accuracy. The newly proposed method is applied to a steady-state experiment and a transient experiment to illustrate how the method can provide insight to the code developer.

• 한국지리정보학회지
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• 제21권1호
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• pp.23-34
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• 2018

최근 대도심지를 중심으로 지반침하, 지반함몰 등 지하공간에서의 안전사고가 빈번히 발생하고 있다. 이에 정부차원에서의 다양한 대응방안을 마련하고 있으며, 이의 일환으로 지하공간통합지도 구축을 추진 중에 있다. 3차원 지반정보는 지하공간통합지도의 핵심 구성요소이며, "지하안전관리에 관한 특별법"에 따라 의무화된 지하안전영향평가의 주요 데이터로 활용된다. 3차원 지반정보의 구축 방법은 지하공간통합지도 구축 기본계획 수립 시 도출되고 국토지반정보 통합DB센터에서 지속적인 구축을 추진하고 있으나, 정확성, 효율성, 활용성을 고려한 구체적인 방안 도출이 필요한 실정이다. 본 연구에서는 지하안전관리 지원을 위해 3차원 지반정보의 정확성, 활용성, 구축 효율성을 고려한 구축 방안을 도출하고자 하였다. 이를 위해 국토지반정보 포털시스템에서 보유한 시추정보와 지반정보 구축 소프트웨어인 MVS, MakeJiban을 활용하여 표고와 지층 기반의 구축 높이 정확도를 비교하였다. 종합적인 분석결과 정확성, 활용성, 효율성 측면에서 원표고 기반의 전체 지층 일괄 구축이 가장 적합한 것으로 판단되었다. 향후, 본 연구결과를 바탕으로 일괄성 있는 3차원 지반정보 구축을 추진할 계획이다.

• 대한공간정보학회지
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• 제24권1호
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• pp.17-24
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• 2016

현재 우리나라는 기후변화로 인해 여름철 집중호우와 국지성 호우가 증가하고 있다. 이에 토사유실 예방에 관한 연구들이 활발하게 이루어지고 있고 산림청에서는 산사태 위험지도를 제공하고 있다. 산사태 위험지도는 9가지의 요소들로 가중치를 주어 5등급화 하여 위험도를 나타낸다. 2014년 8월 25일 부산시 금정구 오륜터널 일대에서 국지성 호우로 인한 토사유실이 발생했으며 산사태위험지도와 비교해 본 결과 실제 토사유실이 발생한 지역은 위험지도상의 안전지대였다. 토사유실이 발생한 오륜터널 일대를 강우량, 토양도, 지질도, 임상도, 경사도, 하계망, 분수령, 유역형상, 유출량을 분석하였다. 분석한 결과 산사태가 발생한 지점의 토양, 임상, 다량의 유출량과 첨두유량, 수계망의 차수, 유역의 형상이 토사유실의 원인요소라고 판단된다. 이 요소 중 산사태 위험지도에서는 고려하지 않은 집중 강우량에 의한 유출량과 첨두유량, 수계망의 차수, 유역의 형상이 산사태의 가장 큰 원인이라고 분석되었다. 기록적인 국지성 호우로 인해 많은 재산피해가 있었던 발생지점 중 하나인 오륜터널 일대의 토사유실원인분석 연구를 통하여 강수량에 의한 유출량, 첨두유량, 유역의 형상이 중요하다고 판단된다. 이 요소들을 산사태 위험지역 판정 시 고려하여 집중호우 시 토사유실에 대비하여야 한다.

• 한국지리정보학회지
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• 제26권4호
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• pp.17-26
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• 2023

지하공간통합지도는 7종의 지하시설물, 6종의 지하구조물, 3종의 지반을 포함한 16종이 하나로 통합된 3차원의 지도이다. 지하공간통합지도의 체계적인 구축·관리·활용을 위해 「지하안전관리에 관한 특별법」으로 제도화 되었다. 그러나 지하공간통합지도 갱신 자동화 기술 등 새로운 기술의 개발과 지하공간통합지도 활용성 확대를 위한 제도적 장치가 부족한 실정이다. 이에 본 연구에서는 지하공간통합지도의 현황을 살펴보고 「지하안전관리에 관한 특별법」의 개정방안과 세부 운영관리규정(안)을 통해 현행 제도의 개선방향을 제시하고자 했다. 개선방향은 크게 3가지로 지하공간통합지도의 제출 창구를 명시화 하고 운영관리규정을 통해 절차를 세분화함으로써 업무의 혼란을 줄일 수 있을 것이다. 그리고 지하공간통합지도 활용 의무대상 사업의 공간적 제약에 대한 내용을 삭제함으로써 모든 굴착공사에서 활용할 수 있도록 하는 등의 개선 방향을 제시하였다. 이와 같은 개선 사항이 제도적으로 반영된다면 디지털트윈 국토의 핵심정보로 지속적인 활용이 될 수 있을 것이다.

• 대한안전경영과학회지
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• 제23권3호
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• pp.57-66
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• 2021

Along with the increase in demand for rescue services, the types of rescue services are also diversifying. Accordingly, rescue workers are exposed to various unpredictable dangerous situations, and the possibility of safety accidents is increasing, so the need for systematic management of safety accidents by rescue teams is emerging. It is necessary to present a roadmap for improving the quality of rescue services. An integrated technology roadmap tool that can be used immediately to improve structural quality was applied. The driving elements of the roadmap are composed of three elements that constitute the improvement of structural quality. It can be divided into safety management, professional competence and other (policy support) fields. This study intends to present a long-term and short-term roadmap by dividing it into safety management, professional competency, and other (policy support) fields.