• 한국농공학회논문집
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• 제60권4호
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• pp.37-48
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• 2018

The extreme 2017 spring drought affected a large portion of central and western South Korea, and was one of the most climatologically driest spring seasons over the 1961-2016 period of record. This drought was characterized by exceptionally low precipitation, with total precipitation from January to June being 50% lower than the mean normal precipitation (1981-2010) over most of western South Korea. In this study, for the quantitative drought impact analysis, the widely-used Standardized Precipitation Index (SPI) and the statistical drought frequency are compared with observed meteorological characteristics and anomalies. According to the drought frequency analysis of monthly cumulative precipitation during January and May in 2017, Gyeonggi-do, Chungcheong-do, and Jeollanam-do areas showed more than drought frequency over 100 years. Gyeongsangnam-do area showed more than drought frequency over 200 years based on annual precipitation in 2017. The South Korean government (Ministry of Agriculture, Food and Rural Affairs (MAFRA) and Korea Rural Community Corporation (KRC)) have been operating a government-level drought monitoring system since 2016. Results from this study can be used to improve the drought monitoring applications of future drought events, as well as drought planning and preparedness in South Korea.

• 한국초등과학교육학회지:초등과학교육
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• 제20권1호
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• pp.59-73
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• 2001

The National Science Fairs has been held in every year for the promotion of science and technology and scientific civil life. The purpose of this study is to survey the current problems in National Science Fairs by making up a question and to improve them. The study makes up a questionnaires about the existing Science Fairs to the teachers who have submitted their works to the Science Fairs and suggest the ways of improvement. The result of questionnaires is that little availability of reference materials, difficulty of paying proper attention to regular classes because of frequent travels, and absence of experimental devices and experimental rooms are perceived as major obstacles in preparing for the exhibition. Respondents teacher also pointed out some problems with the current organization of the exhibition; non-voluntary selection process for the potential authors, separation of research content from regular teaching materials, unrealistically high standard, low participation rate of teachers, so many exhibited works, lack of professionalism in the screening process. The majority however, agreed that the exhibition event should be continuously done, after remedial measures have been taken about the problems. First, the side of science education is emphasized in a purpose of the science fairs to let activity related to science fair be closely connected with school education. Second, students have to be divided according to grade. Third, research level have to be set not too higher than regular instruction content. Fourth, hand book related to science fairs have to be manufactured and spread. Fifth, data of local science fair have to be arranged. Sixth, judging section have to be subdivided and people related to science education have to be included to a judge. Seventh, excellent works have to be support to participate in ISEF.

• 대기
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• 제26권1호
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• pp.159-183
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• 2016

On 31 July 2014, there was a localized torrential rainfall ($58.5mm\;hr^{-1}$) caused by a strong convective cell with thunder showers over Daegwallyeong. In the surface synoptic chart, a typhoon was positioned in the East China Sea and the subtropical high was expanded to the Korean peninsula. A WRF (Weather Research and Forecasting) numerical simulation with a resolution of 1 km was performed for a detailed analysis. The simulation result showed a similar pattern in a reflectivity distribution particularly over the Gangwon-do region, compared with the radar reflectivity. According to the results of the WRF simulation, the process and mechanism of the localized heavy rainfall over Daegwallyeong are as follows: (1) a convective instability over the middle part of the Korean peninsula was enhanced due to the low level advection of warm and humid air from the North Pacific high. (2) There was easterly flow from the coast to the mountainous regions around Daegwallyeong, which was generated by the differential heating of the insolation among Daegwallyeong and the Yeongdong coastal plain, and nearby coastal waters. (3) In addition, westerly flow from the western part of Daegwallyeong caused a strong convergence in this region, generating a strong upward motion combined by an orographic effect. (4) This brought about a new convective cell over Daegwallyeong. And this cell was more developed by the outflow from another thunderstorm cell to the south, and finally these two cells were merged to develop as a strong convective cell with thunder showers, leading to the record breaking maximum rainfall per hour ($58.5mm\;hr^{-1}$) in July.

• 대한원격탐사학회지
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• 제15권4호
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• pp.289-295
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• 1999

Space Physics Sensor (SPS) on-board the KOMPSAT-1 consists of the High Energy Particle Detector (HEPD) and the Ionospheric Measurement Sensor (IMS). The HEPD is to characterize the low altitude high energy particle environment and the effects on the microelectronics due to these high energy particles. It is composed of four sensors: Proton and Electron Spectrometer(PES), Linear Energy Transfer Spectrometer (LET), Total Dose Monitor (TDM), and Single Event Monitor (SEM). 35 MeV proton beam from the medical KCCH cyclotron, at Korea Cancer Center Hospital in Seoul, is used to calibrate the PES. Primary proton beam of 35MeV scattered by polypropylene target is converted to various energy protons according to the elastic collision kinematics. In this calibration, the threshold level of the proton in the PES can be determined and the energy ranges of PES channels are also calibrated.

• 대기
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• 제31권4호
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• pp.433-443
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• 2021

The wind speed and wind direction in Yeongdong are one of the crucial meteorological factors for forecasting snowfall in this area. To improve the snowfall forecast in Yeongdong region, Yeongdong Extreme Snowfall-Windstorm Experiment, YES-WEX was designed. We examined the wind field variation simulated with Local Data Assimilation and Prediction System (LDAPS) using observed wind field during YES-WEX period. The simulated wind speed was overestimated over the East Sea and especially 2 to 4 times in the coastal line. The vertical wind in Yeongdong region, which is a crucial factor in the snowfall forecast, was not well simulated at the low level (850 hPa~1000 hPa) until 12 hours before the forecast. The snowfall distribution was also not accurately simulated. Three hours after the snowfall on the East Sea coast was observed, the snowfall was simulated. To improve the forecast accuracy of snowfall in Yeongdong region, it is important to understand the weather conditions using the observed and simulated data. In the future, data in the northern part of the East Sea and the mountain slope of Taebaek observed from the meteorological aircraft, ship, and drone would help in understanding the snowfall phenomenon and improving forecasts.

• Earthquakes and Structures
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• 제23권3호
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• pp.271-282
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• 2022

Seismic resisting self-centering bridge piers with high energy dissipation and negligible residual displacement after an earthquake event are focus topics of current structural engineering. The energy dissipation components of typical bridge piers are often relatively single; and exhibit a certain level of damage under earthquakes, leading to large residual displacements and low cumulative energy dissipation. In this paper, a novel socket self-centering bridge pier with a hybrid energy dissipation system is proposed. The seismic resilience of bridge piers can be improved through the rational design of annular grooves and rubber cushions. The seismic response was evaluated through the finite element method. The effects of rubber cushion thickness, annular groove depth, axial compression ratio, and lateral strength contribution ratio of rubber cushion on the seismic behavior of bridge piers are systematically studied. The results show that the annular groove depth has the greatest influence on the seismic performance of the bridge pier. Especially, the lateral strength contribution ratio of the rubber cushion mainly depends on the depth of the annular groove. The axial compression ratio has a significant effect on the ultimate bearing capacity. Finally, the seismic design method is proposed according to the influence of the above research parameters on the seismic performance of bridge piers, and the method is validated by an example. It is suggested that the range of lateral strength contribution ratio of rubber cushion is 0.028 ~ 0.053.

• Smart Structures and Systems
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• 제32권3호
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• pp.153-166
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• 2023

Health monitoring of civil infrastructures, in particular, old bridges that are still in service, has become more than necessary, given the risk that a possible degradation or failure of these infrastructures can induce on the safety of users in addition to the resulting commercial and economic impact. Bridge integrity assessment has attracted significant research efforts over the past forty years with the aim of developing new damage identification methods applicable to real structures. The bridge of Ouled Mimoun (Tlemcen, Algeria) is one of the oldest railway structure in the country. It was built in 1889. This bridge, which is too low with respect to the level of the road, has suffered multiple shocks from various machines that caused considerable damage to its central part. The present work aims to analyze the stability of this bridge by identifying damages and evaluating the damage rate in different parts of the structure on the basis of a finite element model. The applied method is based on an inverse analysis of the normal stress responses that were calculated from the corresponding recorded strains, during the passage of a real train, by means of a set of strain gauges placed on certain elements of the bridge. The results obtained from the inverse analysis made it possible to successfully locate areas that were really damaged and to estimate the damage rate. These results were also used to detect an excessive rigidity in certain elements due to the presence of plates, which were neglected in the numerical reference model. In the case of the continuous bridge monitoring, this developed method will be a very powerful tool as a smart health monitoring system, allowing engineers to take in time decisions in the event of bridge damage.

• 지식경영연구
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• 제17권2호
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• pp.131-163
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• 2016

The purpose of this study is to empirically analyze how social comparative learning of forum participants affects learning effects with an emphasis on participants' characteristics. As today's society is changing at a fast pace, the desire for new knowledge and information has grown accordingly. To quench this thirst for knowledge and information, seminars, symposiums, conferences, forums, conventions, exhibitions, and more are taking place as part of knowledge sharing events across the world. Also, the increased need for knowledge and information exchange has led the development and growth of the convention industry and Meetings, Incentives, Conferences, and Events (Exhibitions)(MICE) industry. Especially, forum is a type of event which invites professionals and specialists to discuss diverse topics and share their knowledge and experience with the audience. The participants utilize it as an opportunity to get close to information providers and enjoy the pleasure of knowledge exchange. However, there have been few empirical analyses on who the participants are, why they attend forum, how they pick up and learn new information and knowledge, and what kinds of learning effects they achieve after the event. This paper is to analyze how social comparative learning of the forum's participants influences learning effects based on Albert Bandura's Social Learning Theory (1977, 1997, 1982. 2001) and Leon Festinger's Social Comparative Theory (1950, 1954). By dividing the participants into two groups, one with high level of self-efficacy and the other with low level of self-efficacy, we have examined the differences in learning effects between the two groups using them as moderating variables. This study was conducted in 'MBN Y Forum 2016,' which is one of the most representative knowledge exchange forums of South Korea. An online survey was distributed out and, 1,307(39.2%) out of the total participants of 3,338 have completed the survey. The survey included questions about whether the participants have gained positive or negative motivations by comparing themselves to the speakers (upward comparison learning) and other participants (lateral comparison learning). The results have shown the quality of messages that the speakers are presenting as knowledge providers is the most significant factor that acts on learning effects. Particularly, the participants had higher levels of self-efficacy and self-esteem than average people. They had a clear goal to learn from the speakers (upward comparison) and received positive motivations from them. In other words, no negative learning effects had been found. This presents a managerial implication that having a qualified speaker is necessary for a forum to be successful. On the other hand, the results from the comparison with the other participants (lateral comparison) were different. The participants were likely to compare themselves to the other participants through observational learning. They could compare listening attitudes, language skills, or capabilities to ask a question. The results have showed the participants received positive motivations from the lateral group but at the same time were jealous of abilities of the others. When the quality of a question by a participant is not good enough, it can have a negative influence on the participants' learning effects. The first group with high levels of self-efficacy and self-esteem had no correlation to negative learning effects from the speakers. They rather had a strong desire to learn from the speakers. On the contrary, the participants perceived the lateral group as a learning subset and competitor. The second group with low levels of self-efficacy and self-esteem saw the quasi-group as a rival. This presents that the individual learning effects can be different depending on the participants' characteristics.

• 정신신체의학
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• 제7권1호
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• pp.124-133
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• 1999

연구목적 : 산후우울증은 여러 요인이 관여하여 발생하며, 이들 위험요인에는 다양한 심리사회적 요인이 포함된다. 이전의 여러 연구결과들을 통해 산후우울증의 위험요인이 알려지고 있지만 아직까지 국내에서 산후우울증을 대상으로 위험요인을 연구한 경우는 별로 없다. 본 연구는 국내에서 산후우울증의 심리사회적 위험요인으로는 어떤 것이 있는지를 알아보기 위하여 시행되었다. 방법 : 일신기독병원을 방문한 출산 후 약 6~8주에 있는 산모 119명을 대상으로 하였다. 설문지를 이용하여 산후우울증의 위험요인에 대하여 조사하고 산후우울의 정도를 측정하였다. 설문지는 이전 연구들을 통해 알려진 위험요인들을 참고하고 산모들의 스트레스와 관계되는 요인들을 추가하여 작성하였다. 산후 우울증을 평가하기 위해 EPDS(Edinburgh postnatal depression scale)를 번안해서 사용하였고, 산후우울의 정도는 측정된 EPDS 접수에 따라 판단하였다. 결과 : 총 대상 산모 119명 중 EPDS에 의해 산후우울증으로 진단될 수 있는 고위험군은 16명으로, 13.45%의 빈도를 보였다. 고위험군에서는 과거 우울증상을 경험한 경우와 결혼생활에 대한 만족도가 낮은 경우가 저위험군에 비해 유의하게 많았다, 또 과거 우울증상을 경험하였던 군, 임신중 우울과 불안증상을 경험한 군, 임신 및 산욕기동안 스트레스 생활사를 경험하였다고 보고한 군, 결혼생활에 대한 만족도가 낮은 군, 그리고 나이가 많을수록 EPDS 접수가 유의하게 높았다. 반면, 산모의 교육수준, 종교, 직업의 유무, 임신과 출산에 따른 직업중단 희망임신 여부 분만방법 수유방법, 유아의 입원여부, 그리고 기대했던 유아의 성별 및 실제 유아의 성별은 우울증상에 영향을 미치지 않았다. 결론 : 이상의 결과로 볼 때 산후우울증은 산후에 비교적 높은 빈도로 발생 가능하며, 우울증의 과거력, 임신동안 우울과 불안증상의 경험, 스트레스 생활사, 결혼생활에 대한 낮은 만족도, 그리고 산모의 연령과 같은 요소들이 산후우울증의 위험요인이었다. 임신과 산욕기 동안 산모에 대하여 적절히 정신의학적으로 개입함으로서 조기에 산후우울증을 발견하고 치료할 수 있으며, 산후우울증으로 인하여 산모와 유아에게 미치는 다양한 손실을 예방할 수 있을 것으로 생각된다.

• 한국지구과학회지
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• 제27권6호
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• pp.643-652
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• 2006

동아시아에서 일산화탄소의 지역적 배경 농도 수준을 분석하기 위해, 1991년부터 2004년까지 장기간 중국 Waliguan(WLG), 몽골이아의 Ulaan Uul(UUM), 한국의 태안반도(TAP), 일본의 Ryori(RYO)에서 관측한 일산화탄소 농도를 분석하였다. 연평균 일산화탄소 농도는 $WLG(135{\pm}22ppb),\;UUM(155{\pm}26ppb),\;RYO(171{\pm}36ppb),\;TAP(233{\pm}41ppb)$ 순서로 높은 농도를 보이고 있었다. WLG를 제외하고 전체적으로 봄철에 높고 여름철에 낮은 계절 변동의 특징은 동아시아 다른 지점들에서도 공통적으로 나타나고 있다. TAP는 WLG, UUM, RYO와 비교하여 전체 계절에 높은 일산화탄소 농도를 보이고 있으며 히스토그램에서 넓은 농도 분포를 보이는데 동아시아 대륙, 특히 중국의 가까운 풍하측에 위치하고 있어 광역적 대기 오염의 영향이 크기 때문이다. TAP는 중국 동부 지역을 경유하는 RPC가 봄, 가을, 겨울에서 높은 농도를 나타내었고, 여름철에는 저위도 북태평양으로부터의 OBG에 의해 낮은 일산화탄소 농도를 갖고 있는 해양성 기단의 영향을 받고 있다. NOAA 위성 영상과 GEOS-CHEM 모델 시뮬레이션은 중국 남동부 연안으로부터 황해를 거쳐 한반도와 동해로 확산하고 있는 광역적 대기오염 이동 사례를 확인하고 있다.