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        검색결과 121

        1.
        2024.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, we addressed the prevention of fire extinguishing device malfunction caused by noise in the fire detector of automatic fire extinguishing devices applied to mobile equipment such as armored vehicles and tanks. The automatic fire extinguishing system consists of a fire detection unit, an automatic control unit, and a fire suppression unit. In the case of a fire detector, it is a major component of the fire detection unit. Even though no fire occurred during operation in the field, a number of fire extinguisher sprays occurred, and the malfunction of the fire detector, which is a fire detection unit, was reproduced. The cause was identified as noise in the fire detector connector due to vibration and shock that may occur during operation of the mobility equipment. In order to solve this problem, noise generated momentarily from a fire detector is treated as an exception, and when a fire signal is transmitted from the fire detector to the automatic control unit for more than a certain period of time, Software has been improved to enable fire extinguishers to operate. This study analyzed the causes of malfunctions in automatic fire extinguishing devices, which are components of mobile equipment, and derived improvement measures to improve the reliability of automatic fire extinguishing devices.
        4,000원
        2.
        2024.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : Driving simulations are widely used for safety assessment because they can minimize the time and cost associated with collecting driving behavior data compared to real-world road environments. Simulator-based driving behavior data do not necessarily represent the actual driving behavior data. An evaluation must be performed to determine whether driving simulations accurately reflect road safety conditions. The main objective of this study was to establish a methodology for assessing whether simulation-based driving behavior data represent real-world safety characteristics. METHODS : A 500-m spatial window size and a 100-m moving size were used to aggregate and match the driving behavior indicators and crash data. A correlation analysis was performed to identify statistically significant indicators among the various evaluation metrics correlated with crash frequency on the road. A set of driving behavior evaluation indicators highly correlated with crash frequency was used as inputs for the negative binomial and decision tree models. Negative binomial model results revealed the indicators used to estimate the number of predicted crashes. The decision-tree model results prioritized the driving behavior indicators used to classify high-risk road segments. RESULTS : The indicators derived from the negative binomial model analysis were the standard deviation of the peak-to-peak jerk and the time-varying volatility of the yaw rate. Their importance was ranked first and fifth, respectively, using the proposed decision tree model. Each indicator has a significant importance among all indicators, suggesting that certain indicators can accurately reflect actual road safety. CONCLUSIONS : The proposed indicators are expected to enhance the reliability of driving-simulator-based road safety evaluations.
        4,600원
        3.
        2024.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본고는 현대 중국어의 생성 및 도출 과정에서 실현되는 언어 단위를 구분 짓고 체 계화하여 그 언어 표현 및 운용의 정체성을 구명하였다. 언어는 인간 뇌리의 우주 세계를 말소리라는 형식을 빌려 근사(近似)하게 표현하여 소통하는 정보 처리 기제 이다. 그 과정은 내용과 형식의 층차별 연계를 통하여 구조와 역할의 병행 처리 방 식으로 실현된다. 즉, 은현적(covert) 내부 구조 체계와 외현적(overt) 실제 조작 모 듈(Module)로 구분되어 운용된다. 이를 현대 중국어로 연결하여 살펴보면 다음과 같 다. 첫째, 내용과 형식에 따른 언어 단위의 층차별 연계 관계는 의미자질-음운자질, 의미소-형태소, 개념-어휘, 구성-어절(단어, 구, 절), 판단-문장, 추리-단락 등으로 연결된다. 둘째, 구조와 역할의 관계로 본다면 구조소와 역할체로 나눌 수 있다. 구조 소로는 음운자질, 형태소, 단어, 구, 절과 그것이 갖는 속성인 명사성, 동사성, 형용사 성, 부사성 등이 있으며, 역할체로는 어절(語節)과 그것이 갖는 역할인 성분이 있다. 셋째, 형식과 구조의 측면에서는 음운자질이, 내용과 역할의 측면에서는 어절(語節) 이 현대 중국어를 생성 및 도출하는 데 핵심적인 역할을 수행하고 있다고 할 수 있 다.
        5,700원
        6.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        of hazardous risk factors, risk estimation and determination steps by reflecting the trend of overseas risk assessment. METHODS : In deriving, estimating and determining risk factors, comparing the procedures presented by the ILO with the domestic guidline to find out the differences in procedural. and, According to the domestic manual, after setting the criteria for determining a deterministic perspective, analyze the risk assessment data of a specific domestic company and three overseas risk assessment research data to analyze the differences in methodology domestic and abroad. RESULTS : Within the country, there is a possibility that a deterministic view may be applied to all stages of procedure, and certain corporate data to the risk estimation and determination stage. In the case of overseas, the trend of applying deterministic perspectives to the risk determination stage was confirmed. CONCLUSIONS : Present the need for a standard model for improving deterministic methods in the other two stages, excluding risk determination in the domestic evaluation procedure.
        4,000원
        7.
        2023.11 구독 인증기관·개인회원 무료
        When the parent radionuclide decays, the progeny radionuclide is produced. Accordingly, the dose contribution of the progeny radionuclide should be considered when assessing dose. For this purpose, European Commission (EC) and International Atomic Energy Agency (IAEA) provide weighting factors for dose coefficient. However, these weighting factors have a limitation that does not reflect the latest nuclide data. Therefore, in this study, we analyzed the EC and IAEA methodology for derivation of weighting factor and used the latest nuclide data from ICRP 107 to derive weighting factors for dose coefficient. Weighting factor calculation is carried out through 1) selection of nuclide, 2) setting of evaluation period, and 3) derivation based on ICRP 107 radionuclide data. Firstly, in order to derive the weighting factor, we need to select the radionuclides whose dose contribution should be considered. If the half-life of progeny radionuclides sufficiently short compared to the parent radionuclide to achieve radioactive equilibrium, or if the dose coefficient is greater of similar to that of the parent radionuclide and cannot be ignored, the dose contribution of the progeny radionuclide should be considered. In order not to underestimate the dose contribution of progeny radionuclides, the weighting factors for the progeny nuclides are taken as the maximum activity ratio that the respective progeny radionuclides will reach during a time span of 100 years. Finally, the weighting factor can be derived by considering the radioactivity ratio and branch fraction. In order to calculate the weighting factor, decay data such as the half-life of the radionuclide, decay chain, and branch fraction are required. In this study, radionuclide data from ICRP 107 was used. As a result of the evaluation, for most radionuclides, the weighting factors were derived similarly to the existing EC and IAEA weighting factors. However, for some nuclides, the weighting factors were significantly different from EC and IAEA. This is judged to be a difference in the half-life and branch fraction of the radionuclide. For example, in the case of 95Zr, the weighting factor for 95mNb showed a 35.8% difference between this study and previous study. For ICRP 38, when 95Zr decays, the branch fraction for 95mNb is 6.98×10-3. In contrast, for ICRP 107, the branch fraction is 1.08×10-2, a difference of 54.7%. Therefore, the weighting factor for the dose coefficient based on ICRP 107 data may differ from existing studies depending on the half-life and decay information of the nuclide. This suggests the need for a weighting factor based on the latest nuclide data. The results of this study can be used as a basis for the consideration of dose contributions for progeny radionuclides in various dose assessments.
        8.
        2023.11 구독 인증기관·개인회원 무료
        The Derived Concentration Guideline Level (DCGL) is required to release the facility from the nuclear safety act at the stage of site restoration of the decommissioning nuclear power plant. In order to evaluate DCGL, there are various requirements, and among them, the selection of input parameters based on the application scenario is the main task. Especially, it is important to select input parameters that reflect site characteristics, and at this time, a single deterministic value or a probabilistic distribution can be applied. If it is inappropriate to apply a particular single value, it may be reasonable to apply various distributions, and the RESRAD code provides for evaluation using probabilistic methods. Therefore, this study aims to analyze the difference between the application of the deterministic method and the application of the probabilistic method to the area and thickness of the contaminated zone among the site characteristics data. This study analyzed the thickness and area of the contaminated zone, and in the case of thickness, the deterministic method was applied by changing the thickness at regular intervals from the minimum depth considered by MARSSIM to the thickness of the unsaturated zone identified in previous research data. In addition, a probabilistic analysis was performed by applying a distribution to the thickness of contaminated zone. Second, for the area of the contaminated zone, the dose was evaluated for each area in consideration of the areas to be considered when deriving Area Factor (AF), and the resulting change in DCGL was observed. As a result, the DCGL tends to decrease as the thickness increases, and it seems to be saturated when the thickness exceeds a certain thickness. Therefore, It was confirmed that the level of saturated values is similar to that of entering a probabilistic distribution, and in the case of a parameter that is reasonable to enter as a distribution rather than as a single value, it is sufficiently conservative to perform a probabilistic evaluation. In the case of area change, the DCGL evaluation result showed that the DCGL increased as the scale decreased. The magnitude of the change varies depending on the characteristics of each radionuclide, and in the case of radionuclides where external exposure gamma rays have a major exposure effect, the change is relatively small. It can be seen that the change in DCGL according to the area has the same tendency as the AF applicable to the survey unit for small survey units applied in the final status survey.
        9.
        2023.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : The purpose of this study is to derive dropout rates according to various international roughness index (IRI) specifications using ProVAL, develop a comparative methodology, and indirectly assess the level of road management in each country. METHODS : Based on a literature review, the IRI specifications for each country were collected, and the ProVAL analysis tool was used to compare and analyze dropout rates according to each specification. Thus, the dropout rate rankings for each country were calculated. Additionally, by analyzing the correlation between dropout rates according to each threshold, a model was created to convert the threshold between the most commonly used baseline distances of 100 m and 161 m. RESULTS : Dropout rates were derived according to the standards of each country and rankings were assigned. Comparing 51 standards, the IRI level of New Mexico appeared to be the highest, whereas the domestic specifications ranked 36th. A model was created to convert the threshold between the standard distances of 100 m and 161 m. CONCLUSIONS : This study objectively assessed the roughness standards in various countries using the dropout rate and IRI ranking specifications. The highest specification was found for the asphalt of New Mexico in the USA, with the domestic specification ranking 36th. A model that converts the thresholds between the most commonly used baseline distances of 100 m and 161 m was developed, with slight differences across sections. For a precise conversion, individual models may be required for each section.
        4,000원
        10.
        2023.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 난대상록수종인 종가시나무에 대한 수간곡선식의 도출과 재적표의 작성 및 탄소배출계수를 이용하여 탄소저장, 흡수량을 추정하고자 수행하였다. 분석에 사용된 공시목은 전남, 경남, 제주 등에서 수집된 468본이며, 수간형태를 도출하기 위하여 적용한 수간곡선 모형은 Kozak 모델이다. 이 모델의 적합도는 0.9452, 편의는 0.0807, 추정치 표준오차의 백분율은 1.7145, 평균절대편차는 1.2655로 각각 나타났다. 종가시나무의 개체목 재적은 Kozak 수간곡선 모델에 Smalian 재적식을 적용시켜 산출하였으며, 수고와 흉고직경급별로 재적표를 작성하였다. 그리고 붉가시나무 재적표와 이번에 만든 종가시나무 재적표를 서로 비교한 결과(t-test), 통계적으로 두 집단 간에 차이가 없는 것으로 나타났다. 따라서 이들 재적표는 두 수종 중 하나만 이용하거나, 둘을 하나로 통합하여도 문제가 없을 것으로 판단된다. 한편 종가시나무림의 탄소저장 및 흡수량은 산림바이오소재연 구소 시험림의 조사구를 대상으로 하였다. 이들 조사구를 대상으로 탄소저장 및 흡수량을 계산한 결과, 생육상태가 양호한 시험구(A)에서 탄소저장량 은 93.17 C ton/ha, 그리고 탄소흡수량은 13.14 CO2 ton/ha/yr 인 것으로 나타났다. 반면에 생육이 저조한 시험구(B)의 탄소 저장 및 흡수량은 양호한 시험구보다 약 1/3 정도 낮게 나타났다.
        4,000원
        11.
        2023.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구의 목적은 인지적 안녕감 수준에 따라 감정 경험에 차이를 보이는지 확인하고, 인지적 안녕감 수준을 강하 게 예측하는 대표적인 구체적 감정들이 무엇인지 확인함으로써 일상에서 사람들이 어떠한 감정을 관리하는 것이 전 체적인 삶의 만족도 증진에 효과적인지에 대한 실용적 방안을 모색하고자 함에 있다. 이를 위해 참가자간 요인설계 (between-subjects factorial design)를 채택하여 학부생 438명을 대상으로 인지적 안녕감 수준에 따른 감정 경험 빈도 를 측정하였다. 인지적 안녕감은 생활만족도 척도(SWLS)로 측정하였으며, 감정 빈도는 PANAS-X 척도로 측정하였고, 조사 후 인지적 안녕감의 평균값을 기준으로 집단을 나누어 감정 프로파일을 살펴보았다. 연구결과, 첫째, 인지적 안녕감이 높은 집단은 낮은 집단에 비해 전반적으로 긍정감정, 놀람감정의 경험빈도가 높았고 부정감정 경험빈도가 낮았다. 둘째, 인지적 안녕감에 영향을 미치는 대표적인 감정은 긍정 8개, 부정 7개, 놀람 1개임을 확인하였다. 특히 긍정은 ‘즐거운(happy)’, ‘자신감 있는(confident)’, 부정은 ‘나 자신에게 만족하지 못하는(dissatisfied with self)’, ‘나 자신이 역겨운(disgusted with self)’, 놀람은 ‘경탄을 자아내는(amazed)’ 감정이 인지적 안녕감에 가장 큰 영향력을 미쳤다. 본 결과를 통해 일상에서 경험하는 감정을 무조건 긍정-부정으로만 살펴볼 것이 아니라, 인지적 안녕감을 증진시키기 위해서는 특정한 감정들의 경험 빈도는 높이고(ex. 즐거움, 자신감), 특정한 감정의 경험 빈도는 줄이는 것(ex. 자신에 대한 불만족, 역겨움)이 더 효과적일 수 있음을 시사한다.
        5,200원
        12.
        2023.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Seismic fragility curves play a crucial role in assessing potential seismic losses and predicting structural damage caused by earthquakes. This study compares non-sampling-based methods of seismic fragility curve derivation, particularly the probabilistic seismic demand model (PSDM) and finite element reliability analysis (FERA), both of which require employing sophisticated finite element analysis to evaluate and predict structural damage caused by earthquakes. In this study, a three-dimensional finite element model of API 5L X65, a buried gas pipeline widely used in Korea, is constructed to derive seismic fragility curves. Its seismic vulnerability is assessed using nonlinear time-history analysis. PSDM and a FERA are employed to derive seismic fragility curves for comparison purposes, and the results are verified through a comparison with those from the Monte Carlo Simulation (MCS). It is observed that the fragility curves obtained from PSDM are relatively conservative, which is attributed to the assumption introduced to consider the uncertainty factors. In addition, this study provides a comprehensive comparison of seismic fragility curve derivation methods based on sophisticated finite element analysis, which may contribute to developing more accurate and efficient seismic fragility analysis.
        4,000원
        13.
        2023.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Recently, small and medium-sized manufacturing companies have shown increased interest in and participation in smart factories in order to survive in market competition. However, many SMEs build smart factories without a systematic review or preparation, which leads to them not being able to use them properly. This study considers the main reason for the low utilization rate of smart factories to be a lack of sufficient reflection of user requirements. Therefore, a method and procedure for deriving the priority of smart factory requirement functions and operating performance indicators based on QFD is proposed as a solution to this issue.
        4,800원
        14.
        2023.05 구독 인증기관·개인회원 무료
        Radioactive waste generated during nuclear power plant decommissioning is classified as radioactive waste before the concentration is identified, but more than 90% of the amount generated is at a level that can be by clearance. However, due to a problem in the analysis procedure, the analysis is not carried out at the place of on-site but is transported to an external institution to identify concentration, which implies a problem of human error because 100% manual. As a way to solve this problem, research is underway to develop a mobile radioactive waste nuclide analysis facility. The mobile radionuclide analysis facility consists of a preparation room, a sample storage room, a measurement room, a pretreatment room, and a waste storage room, and is connected to an external ventilation facility. In addition, since the automation module is built-in from the sample pre-threatening step to the separation step, safety can be improved and rapid analysis can be performed by being located in the decommissioning site. As an initial study for the introduction of a mobile nuclide analysis facility, Visiplan, a preliminary external exposure evaluation code, was used to derive the analysis workload by a single process and evaluate the exposure dose of workers. Based on this, as a follow-up study, the amount of analysis work according to the continuous process and the exposure dose of workers were evaluated. As a result of the evaluation, the Regulatory dose limit was satisfied, and in future studies, internal and external exposure doses were evaluated in consideration of the route of movement, and it is intended to be used as basic data in the field introduction process.
        15.
        2023.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        To transform old words into new words is a very efficient mode of word derivation in contemporary Chinese, which mainly involves the transformation of word form and the transformation of meaning. In the process of transforming the old words language users have created a lot of new words that are very novel in form or meaning based on the relationship between Chinese characters in terms of sound, shape and meaning or the structural features of Chinese characters. This paper lists more than 130 new appellations including sound-based words, form-based words, meaning-based words and words produced by changing the structure of Chinese characters, names the ways how old words transform into new words as JieYinFuXing, XieYinFuYi, BieJieFuYi, FanBeiFuYi, GaiZiBianXing and describes the transformation process of these words. These lexical phenomenons reflect some language psychology such as pursuing new differences, playing jokes and mental association. They have some impacts on the lexical system of contemporary Chinese as they open up new ways for the generation and change of contemporary Chinese words, they supplement the word-making methods and lead to some unconventional combinations in contemporary Chinese lexis. This paper intends to further clarify the important role of Chinese characters in word creation and word development, and deepen the understanding of Chinese Character study and contemporary Chinese lexicology.
        5,800원
        16.
        2023.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In modern society, the delivery service market has grown explosively due to rapid changes in social structure and the recent COVID-19 pandemic. Therefore, various problems such as injury to workers and an increase in human accidents are occurring due to the loading and unloading of parcels. In order to solve this problem, domestic company n is developing a “robot-based cargo loading and unloading system”. In developing a new technology system, quantitative reliability targets should be set for efficient operation and development. In this paper, reliability analysis was conducted through field data for the pneumatic gripper of the “robot-based cargo loading system”. The reliability of the failure data was analyzed to estimate the distribution parameters and MTTF. Random data was derived for the probability of occurrence of a failure with the estimated value. By repeating the simulation to predict the number and year of failures according to the estimated parameters of the probability distribution, it was proposed as a method that reflects realistic probabilities rather than calculating with simple arithmetic using the average MTTF previously used in the field.
        4,000원
        17.
        2022.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        마을숲은 농촌마을의 대표적 경관이자 녹지 환경으로서의 생태적 기능을 비롯하여 마을의 다양한 문화가 이루어지는 공간 제공의 기능을 가지고 있다. 본 연구에서는 생태계서비스의 개념적 틀을 응용하여 마을숲의 가치를 측정할 수 있는 평가 지표를 도출하고자 하였다. 먼저 생태계서비스 평가와 관련한 국제 기준의 검토를 통하여 평가지표로 공급, 조절, 지지, 문화의 4개 대분류를 설정하고 28개의 세부항목을 설정하였다. 마을숲과 관련된 21개의 문헌에서 나타난 마을숲의 기능, 역할, 효과 등을 평가 항목에 맞추어 분류하고 각 유형별 세부 내용을 고찰하였다. 과거와 현재의 마을숲 기능을 고려하여 전문가 브레인스토밍을 통해 4개 유형 24개의 평가 항목을 선정하였다. 도출된 평가 항목으로 4개 마을숲의 주민을 대상으로 중요도를 평가하여 신뢰성을 분석한 결과 24개 문항의 크론바흐 알파 계수가 0.857로, 신뢰성이 높은 수준이나, 공급의 3개 항목, 지지의 1개 항목을 제외하면 신뢰성이 더 높아진다. 또한 각 항목별로 중요도를 분석하면 공급기능은 중요도가 보통보다 낮은 수준이었으며 이는 현재 마을숲에서의 공급기능은 거의 이루어지지 않기 때문인 것으로 판단된다. 신뢰도와 중요도의 결과를 바탕으로 최근 마을숲에서 중요도가 낮은 공급 기능 3개 항목과 신뢰성이 낮았던 지지 기능 1개 항목 등 4개 항목을 제외한 20개 항목을 마을숲의 생태계서비스 평가지표로 도출하였다.
        4,000원
        18.
        2022.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        최근 도심항공모빌리티(UAM) 상용화에 앞서 도심 내 항공 교통수단 관련 산업에 대한 연구개발 중요성이 급격히 증가하고 있다. 도심항공모빌리티(UAM) 환경을 조성하기 위해서 핵심 항공 이동 수단 비행체인 개인용 항공기 (PAV) 기체에 관한 연구가 수행되고 있으나, 탑승자 관점의 연구가 상대적으로 부족한 상황이다. 특히 PAV는 탑승 자의 새로운 생활공간으로 활용될 것으로 예상되기 때문에 탑승자의 실내행위를 지원하는 실내공간 설계를 위해서 는 PAV 기체에서 발생하는 물리적 요소가 인체에 미치는 영향에 관한 연구가 필수적으로 이루어져야 한다. 이에 본 연구의 목적은 PAV의 공중 운항 특성으로 인해 인체에 영향을 주는 제약 요소를 도출하고, 이러한 제약 요소가 실내행위를 수행하는 탑승자 인체에 미치는 영향을 파악하는 것이다. 본 연구 결과, 항공 이동 수단 비행 기체 PAV 는 4,000ft 이하에서 운항해야 하는 기준에 따라, 운항고도에 따른 제약 요소는 소음, 진동, 저주파 운동에 의한 멀미 로 나타났다. 이러한 제약 요소가 실내행위에 영향을 미친다는 관점에서 PAV에서 행할 수 있는 실내행위를 자율주 행 자동차, 비행기, PAV 컨셉 사례를 활용하여 도출하고 인체에 미치는 영향과 수준을 고려하여 실내행위 지원을 위한 제약 요소 권장기준을 설정하였다. 또한 실내행위 지원을 위한 제약 요소의 인체 영향 수준을 감소시키기 위해 서는 시트의 형태 및 내장기능(진동 저감 기능, 온도조절, LED조명 등), 개인 좌석별 지향성 스피커를 활용한 외부소 음 감소, 소음과 진동 감소를 위한 내장재 등을 실내공간 설계에 반영해야 함을 제시하였다. 본 연구는 PAV 실내행 위에 영향을 주는 제약 요소를 도출하였고, 인체에 미치는 영향 수준을 확인하였으며, 추후 PAV 실내 설계 시 기초 자료로써 활용할 수 있다는 점에서 의미가 있다.
        5,200원
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