• Structural Engineering and Mechanics
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• 제91권1호
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• pp.25-38
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• 2024

After the mainshock, whether the train can be allowed to pass the bridges plays an important role in ensuring the transport of supplies and rescue works for example, in the "12 May" earthquake in China, after evaluation, the bridge was still used for transportation in rescue at a very slow speed, engineers usually evaluate whether the train can pass the bridge safely based on the experience, lacks sufficient calculation basis and does not fully consider the risk caused by aftershocks. To address this issue, this paper comprehensively considers the randomness of track irregularity, the randomness of aftershock intensity and other multiple random sources in train-bridge interaction system (TBIS). The sensitivity of train to various random parameters after earthquake is analyzed from the perspective of probability, the most sensitive random variable in this paper is PGA of aftershocks, both for bridge and trailer car, With the increase of epicentral distance, the sensitivity of PGA will decrease, and correspondingly, for trailer car, the sensitivity of other random variables will increase, research in this paper provides a basis for the subsequent random analysis of post-earthquake driving safety.

• 기술혁신학회지
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• 제9권1호
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• pp.1-25
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• 2006

세계화, 다변화 경쟁 속에 연구개발을 통한 기술혁신은 기업의 지속가능한 성장을 위한 경쟁우위의 핵심역량으로 인식되고 있다. 이에 기술혁신과 기업성과의 관계에 대한 관심이 집중되고 있으나, 기존 연구는 이를 개념적이거나 정성적 수준에서 다루어 왔으며, 주로 혁신활동에 집중되어 왔다. 본 연구에서는 기업의 특성에 따라 기술혁신과 기업성과의 관계를 11년간 162개 국내 하이테크 기업을 대상으로 횡단면 시계열자료를 통해 실증적으로 분석하였다. 국내기업의 기술혁신 특성으로 규모효과를 제거한 특허강도, 연구개발강도, 무형자산강도를 대리지표로 사용하였고, 기업성과를 위해 순이익을 대리지표로 사용하였다. 11년간의 장기분석을 위해 변수를 실질가치화하여 분석한 결과 기업성과는 특허강도와 연구개발강도와 양의 관계를 가짐을 확인하였다. 또한 기업의 기술혁신 특성에 따라 분류한 8개 범주별 기업성과의 차이가 나타남을 밝혔다. 이를 통해 높은 특허강도와 연구개발강도를 보이는 기업일수록 높은 기업성과를 향유하고 있음을 알 수 있었다.

• 한국물환경학회지
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• 제20권5호
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• pp.494-499
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• 2004

Growth in population and urbanization has progressively increased the loadings of pollutants from non-point sources as well as point sources. Therefore, it is necessary to manage both point and non-point sources contaminations for protecting water environment and improving water quality. This study investigated the characteristics of pollutant release over a wide range of rainfall intensities as a requisite to control road runoff that accounts for the largest portion of non-point source contamination in urban areas. Samples of runoff rainwater collected from real road surfaces were analyzed for physicochemical parameters such as pH, suspended solids, and heavy metals. A experimental model road ($30cm{\times}30cm$) was also used to evaluate wash-off properties of pollutants deposited on the surface as functions of time and rainfall intensity. Analysis of runoff samples on rain events showed that the pollutant wash-off patterns for heavy metal and suspended solids were similar. This implies that the particles in rainwater adsorb heavy metals. Experiments using the model road made of impervious asphalt demonstrate a strong first flush phenomenon. At high rainfall intensity, approximately 80% of total pollutants were released within 15 min. The pollutant wash-off rates rapidly increase from 9 mm/hr to 12 mm/hr of rainfall intensity and decrease over 12 mm/hr of rainfall intensity.

• 디지털융복합연구
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• 제15권1호
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• pp.527-536
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• 2017

연구는 체육계열 대학생이 인식한 경력개발지원과 구직강도의 관계에서 구직효능감의 매개효과의 관계를 규명하는데 목적이 있다. 이러한 연구 목적을 달성하기 위한 연구대상은 서울, 충남, 경상권에 소재한 대학교의 체육전공자 중 3, 4학년을 대상으로 223명의 자료를 수집하였다. 수집된 자료는 SPSS 20.0 프로그램을 이용하여 설문지의 신뢰도와 타당도검사, 상관분석을 실시하였으며, 경로분석은 AMOS 20.0 프로그램을 이용하여 분석을 실시하였다. 이러한 과정을 통해 얻어진 결과는 다음과 같다. 첫째, 체육계열 대학생이 인식한 경력개발지원은 구직효능감에는 통계적으로 정적인 영향을 미치고, 구직강도에는 통계적으로 유의미한 영향을 미치지 못했다. 둘째, 체육계열 대학생의 구직효능감은 구직강도에 통계적으로 정적인 영향을 미쳤다. 셋째, 체육계열 대학생이 인식한 경력개발지원과 구직강도 사이에서 구직효능감은 완전 매개효과가 있는 것으로 나타났다.

• Radiation Oncology Journal
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• 제34권1호
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• pp.64-75
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• 2016

Purpose: In order to evaluate the relationship between the dose to the liver parenchyma and focal liver reaction (FLR) after stereotactic ablative body radiotherapy (SABR), we suggest a novel method using a three-dimensional dose distribution and change in signal intensity of gadoxetate disodium-gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) hepatobiliary phase images. Materials and Methods: In our method, change of the signal intensity between the pretreatment and follow-up hepatobiliary phase images of Gd-EOB-DTPA-enhanced MRI was calculated and then threshold dose (TD) for developing FLR was obtained from correlation of dose with the change of the signal intensity. For validation of the method, TDs for six patients, who had been treated for liver cancer with SABR with 45-60 Gy in 3 fractions, were calculated using the method, and we evaluated concordance between volume enclosed by isodose of TD by the method and volume identified as FLR by a physician. Results: The dose to normal liver was correlated with change in signal intensity between pretreatment and follow-up MRI with a median $R^2$ of 0.935 (range, 0.748 to 0.985). The median TD by the method was 23.5 Gy (range, 18.3 to 39.4 Gy). The median value of concordance was 84.5% (range, 44.7% to 95.9%). Conclusion: Our method is capable of providing a quantitative evaluation of the relationship between dose and intensity changes on follow-up MRI, as well as determining individual TD for developing FLR. We expect our method to provide better information about the individual relationship between dose and FLR in radiotherapy for liver cancer.

• 한국방사선학회논문지
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• 제7권4호
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• pp.265-269
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• 2013

뇌척수액을 생산하고 있는 choroid plexuse를 확산강조영상 검사기법에 따라 신호강도를 분석하여 임상적인 유용성을 알아보고자 하였다. $T2^*$-DW-EPI 기법을 적용하여 choroid plexus가 고 신호 강도를 보이는 대상자를 추가적으로 FLAIR-DW-EPI 기법을 적용하여 영상을 얻었다. 두 기법으로 얻은 확산강조영상을 가지고 choroid plexus의 신호강도와 확산계수를 구하여 비교하였다. 그 결과 FLAIR-DW-EPI 기법에서는 choroid plexus의 신호가 뇌 실질과 같거나 저 신호로 나타나 두 기법간의 신호강도의 차이가 있음을 확인하였다. 이는 $T2^*$-DW-EPI 확산강조영상에서 choroid plexus가 고 신호를 보인 환자의 경우 FLAIR-DW-EPI 기법을 추가로 검사하여 정보를 제공함으로서 choroid plexus의 질병 유무를 진단하는데 도움이 될 것으로 생각한다.

• 품질경영학회지
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• 제49권1호
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• pp.17-29
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• 2021

Purpose: During 2015-2019, the average amount of political donation to the national assembly members in Korea was 1,000 won per person. Despite its benefits such as receiving tax credits, the donation system has not been actively practiced. This paper aims to promote political donations by suggesting a recommendation system of national assembly members by analysing the bills they proposed. Methods: In this paper, we propose a recommendation system based on two aspects: how similar the newly proposed or ammended bills are to the sponsors' interest (similarity index) and how much effort national assembly members put into those bills (intensity index). More than 25,000 bills were used to measure the recommendation quality index consisted with both the similarity and the intensity indices. Word2vec was used to calculate the similarity index of the bills proposed by the national assembly member to the sponsor's interest. The intensity index is calculated by diving the number of newly proposed or entirely revised bills with the number of senators who took part in those bills. Subsequently, we multiply the similarity index by the intensity index to obtain the recommendation quality index that can assist sponsors to identify potential assembly members for their donation. Results: We apply the proposed recommendation system to personas for illustration. The recommendation system showed an average f1 score about 0.69. The analysis results provide insights in recommendation for donation. Conclusion: n this study, the recommendation system was proposed to promote a political donation for national assembly members by creating the recommendation quality index based on the similarity and the intensity indices. We expect that the system presented in this paper will lower user barriers to political information, thereby boosting political sponsorship and increasing political participation.

• 아태비즈니스연구
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• 제14권4호
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• pp.175-189
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• 2023

Purpose - The purpose of this study was to examine the relationship between CEO name uncommonness and R&D intensity while focusing on CEO ownership and CEO tenure as moderators of the relationship. Design/methodology/approach - This study collected data from various American databases such as national data on given names from Social Security Administration, COMPUSTAT, and Execucomp. The sample of this study includes 2,494 (firm-year) observations from U.S. firms between 2005-2011. This study conducts Feasible Generalized Least Square (FGLS) regression analysis to test the hypotheses. Findings - First, we found CEO name uncommonness was positively related to R&D intensity. In other words, CEOs with unusual names prefer being distinctive by increasing R&D investments. Second, we examine the moderating roles of CEO characteristics (i.e., CEO ownership and tenure). The results show that CEO tenure strengthens the positive relationship between CEO name uncommonness and R&D intensity. Research implications or Originality - First, this study extends the CEO characteristics and R&D literature by investigating how CEO name uncommonness affects R&D intensity. In addition, our study also supports the intitutionalization of CEO power arguments by showing that CEOs with unusual names are more likely to pursue distinctive strategies when they have longer tenure. For practical implications, our results allow the investors to better predict corporate future R&D expenses. It suggests that ceteris paribus, CEOs with unusual names, vis-a-vis CEOs with common names, are more likely to increase R&D expenses.

• 대기
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• 제20권2호
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• pp.131-151
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• 2010

This study establishes a conceptual model to analyze heavy rainfall events in Korea using multi-functional transport satellite-1R satellite images. Three heavy rainfall episodes in two major synoptic types, such as synoptic low (SL) type and synoptic flow convergence (SC) type, are analyzed through a conceptual model procedure which proceeds on two steps: 1) conveyer belt model analysis to detect convective area, and 2) cloud top temperature analysis from black body temperature (TBB) data to distinguish convective cloud from stratiform cloud, and eventually estimate heavy rainfall area and intensity. Major synoptic patterns causing heavy rainfall are Changma, synoptic low approach, upper level low in the SL type, and upper level low, indirect effect of typhoon, convergence of tropical air in the SC type. The relationship between rainfall and TBBs in overall well resolved areas of heavy rainfall. The SC type tended to underestimate the intensity of heavy rainfall, but the analysis with the use of water vapor channel has improved the performance. The conceptual model improved a concrete utilization of images and data of satellite, as summarizing characteristics of major synoptic type causing heavy rainfall and composing an algorism to assess the area and intensity of heavy rainfall. The further assessment with various cases is required for the operational use.

• 한국산학기술학회논문지
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• 제12권7호
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• pp.2975-2981
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• 2011

본 논문에서는 얼굴 영상 처리와 음성 신호처리를 적용하여 오미자차가 인체 장기에 효과가 있는 차인지 그리고 있다면 어느 장기에 효용이 있는지에 대한 분석 방법을 제안하고자 한다. 이를 위해 우선 영상처리를 통해 오미자차를 섭취하기 전과 후의 얼굴 영상에서 우측 뺨 영역의 색상 변화를 비교 분석하였다. 아울러 오미자차 효능에 대해 보다 많은 사실 확보를 위해 성대 진동 및 음성 에너지의 크기를 분석하는 음성분석 실험을 수행하였다. 실험 결과 오미자차 섭취에 의해 폐의 기능이 원활해지면서 성대 진동 및 에너지 크기가 안정적으로 변했으며 오른쪽 뺨 부위의 b값이 증가하는 현상이 나타났다.