• Mass Spectrometry Letters
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• 제6권1호
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• pp.13-16
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• 2015

This study demonstrated the stabilizing role of a cyclodextrin on Keggin $[PW_{12}O_{40}]^{3-}$ via hydrogen bonding complexation unveiled by ESI-MS. The distinctive fragmentation pathways of the $\{PW_{12}\}/{\gamma}$-CD complexes from that of discrete $[PW_{12}O_{40}]^{3-}$ showed that the so-called "weak" non-covalent interactions can effectively change the dissociation chemistry of POM in the gas phase. The influence of different types of solvents and organic additives such as ${\gamma}$-CD on the stability of Keggin $[PW_{12}O_{40}]^{3-}$ was also addressed firstly by ESI-MS.

• Journal of Astronomy and Space Sciences
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• 제35권2호
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• pp.93-103
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• 2018

Non-specular, vertically upward transit, fast-moving radar echoes are observed in the summer polar upper mesosphere near 90 km using 52 MHz VHF radar at Esrange, Sweden. By resolving maximum echo power movement, the unusual meteor trails propagate vertically upward with taking horizontal displacements at an initial speed of 10 km/s exponentially decreasing with increasing height from 85-89 km, lasting for 3.5 sec. Another upward transit is observed as following a downward transit echo target in about ~1 sec, lasting over 5 sec. The upward motion cannot be explained with the dynamics of penetrating meteors or by atmospheric dynamics. The observation proposes that secondary produced plasma jets occurring from meteor trail are possibly responsible for upward fast moving echoes. The long-lasting (3-5 sec), ascending meteor trails at speeds of a few $10^4m/s$ are distinctive from any previous occurrences of meteors or upper atmospheric electrical discharges in the aspect of long-lasting upward/downward motions. This result possibly suggests a new type of meteor-trail leader discharge occurring in the summer polar upper mesosphere and lower thermosphere.

• 한국게임학회 논문지
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• 제8권4호
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• pp.45-53
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• 2008

전 세계적으로 인기를 구가하고 있는 블리자드사(社)의 "World of warcraft"의 서사구조를 살펴보았다. 서사학(narratology)과 게임학(Ludology)은 별도의 이론으로 존재하기 보다는 예술이라는 거대 담론 속에서 서로 상호적인 교류가 이루어져야 하며, 놀이의 환경 속에 게임의 룰이 접목되어 상호 융합되었을 때, 게임의 극적인 서사가 구성된다고 보았다. "와우"의 전체적인 서사구조와 퀘스트 및 PvP 혹은 일반적인 사냥에서 드러나는 부분적인 서사구조를 통해 "와우"가 지닌 폭발적인 인기의 힘을 살펴보았다. 게임에 숨겨진 선형적 오리지널 스토리와 멀티시나리오의 스토리 줄기에서 랜덤하게 드러나는 비선형적인 자유도에서 베어 나오는 이야기의 흐름은 "와우"가 지닌 서사의 특징이다.

• 비파괴검사학회지
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• 제32권1호
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• pp.7-11
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• 2012

기존 진단법과 달리 동적 하중조건하 회전체의 마모 단계에 따른 결함 진단을 위해 비접촉, 비파괴의 적외선 열화상 기법이 제안된다. 본 연구에서는 시험시편인 단열 깊은 홈의 볼 베어링을 설정하여 기존의 스펙트럼 분석과 같은 고장탐지법에 대한 대안으로써 수동형 열화상시험이 수행되었다. 본 연구로부터, 적외선 열화상시험은 신뢰성을 평가하기 위해 기존 진동 스펙트럼 분석시험과 비교, 분석되었다. 연구의 비파괴시험의 결과로써, 마모 단계에 따른 볼 베어링의 온도 특성이 분석되었다.

• 한국병원경영학회지
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• 제spc호
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• pp.85-95
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• 2016

This study is to introduce a comprehensive framework of a crisis management system developed at a prominent hospital in South Korea. Throughout recent decades, especially in the recent years, the way in which to cope with both internal and external challenges has been one of the most critical issues. Since the incident management system in the U.S. is acknowledged as the most advanced crisis management model in the world, a portion of this study refers to the Hospital Incident Command System(HICS) provided by the California Emergency Medical Services Authority(EMSA). Nevertheless, the framework suggested in this article was designed based on a distinctive Korean hospital setting. The main contents of this study are as follows; categorization of each type of crisis, organization of a crisis management team in a non-crisis or crisis state, crisis assessment by life cycle stage, and establishment of crisis management protocol. Even though many types of crises are unspecified, those can be categorized into external crisis, medical crisis, and utility & activity failure. A crisis management organization should be operated and consisted differently- depending on a crisis or non-crisis situation. From a life-cycle perspective, the range by which the crisis should be managed extends from pre-stage to post-stage of the crisis. It is important to set proper scenarios and manuals by crisis type to develop a crisis management framework of high quality. With continuous efforts, hospitals can prepare for the uncertainty to better concentrate on core business operations.

• 한국게임학회 논문지
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• 제7권4호
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• pp.81-92
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• 2007

최근 들어 NPR(Non-Photorealistic Rendering) 기법을 이용한 게임들이 많아지고 있다. 그렇지만 게임에서 적용하고 있는 NPR 기법들은 몇 가지 종류로 한정되며, 특히 카툰렌더링에 집중되고 있다. 본 논문에서는 그간 연구가 거의 이루어지지 않았던 게임에 적용 가능한 코믹북 스타일의 NPR 기법을 제안한다. 이를 위해 먼저 코믹북의 비주얼과 셀 애니메이션 비주얼의 차이점을 비교, 분석하여 코믹북 스타일의 비주얼에 대한 표현 요소를 도출한다. 다음으로, 도출된 세 가지 표현 요소, 외곽선 스케치, 톤, 해칭을 효과적으로 구현하기 위한 렌더링 알고리즘들을 제시한다. 마지막으로 이 알고리즘이 적용된 게임을 제작함으로써 게임을 위한 알고리즘으로 적용이 가능한지를 검증한다.

• Nuclear Engineering and Technology
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• 제55권7호
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• pp.2373-2379
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• 2023

In sodium systems, leakage is one of the safety concerns; it can cause chemical reactions, which may result in fires. There are contact and non-contact types of leak detectors, and the conventional method of non-contact type detection is by gas sampling. Because of the complexity of this method, there has always been a need for a simple gas sensor, and the resistive-type nanostructure ZnO sensor is a promising option with various advantages. In this study, a ZnO sensor was fabricated, and the concept was tested as a leak detector using a dedicated experiment facility. The experiment results showed distinctive changes in resistance with the presence of sodium aerosol under various conditions. Replacing the conventional gas sampling with the ZnO sensors is expected to enable identification of the leakage location if used as a point-wise instrumentation and to greatly reduce the total cost, making the system simple, light, and effective. For further study, more tests will be performed to evaluate the sensitivity of key parameters under various conditions.

• Educational Technology International
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• 제15권2호
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• pp.71-88
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• 2014

A variety of studies to predict students' performance have been conducted since educational data such as web-log files traced from Learning Management System (LMS) are increasingly used to analyze students' learning behaviors. However, it is still challenging to predict students' learning achievement in blended learning environment where online and offline learning are combined. In higher education, diverse cases of blended learning can be formed from simple use of LMS for administrative purposes to full usages of functions in LMS for online distance learning class. As a result, a generalized model to predict students' academic success does not fulfill diverse cases of blended learning. This study compares two blended learning classes with each prediction model. The first blended class which involves online discussion-based learning revealed a linear regression model, which explained 70% of the variance in total score through six variables including total log-in time, log-in frequencies, log-in regularities, visits on boards, visits on repositories, and the number of postings. However, the second case, a lecture-based class providing regular basis online lecture notes in Moodle show weaker results from the same linear regression model mainly due to non-linearity of variables. To investigate the non-linear relations between online activities and total score, RF (Random Forest) was utilized. The results indicate that there are different set of important variables for the two distinctive types of blended learning cases. Results suggest that the prediction models and data-mining technique should be based on the considerations of diverse pedagogical characteristics of blended learning classes.

• Journal of Korean Neurosurgical Society
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• 제59권6호
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• pp.584-589
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• 2016

Objective : A rare subtype of meningioma, sclerosing meningioma is not included in the current World Health Organization classification of meningiomas and is classified into the category of other morphological variation subtypes. Sclerosing meningioma is often misdiagnosed to other non-benign meningioma or malignant neoplasm, so it is important to diagnose sclerosing type correctly. We analyzed the radiological and clinical characteristics of a series of sclerosing meningiomas. Methods : Twenty-one patients who underwent surgery in one institute with a histopathologically proven sclerosing meningioma were included from 2006 to 2014. Eighteen tumors were diagnosed as a pure sclerosing-type meningioma, and 3 as mixed type. Magnetic resonance image was taken for all patients including contrast enhancement image. Computed tomography (CT) scan was taken for 16 patients. One neuroradiologist and 1 neurosurgeon reviewed all images retrospectively. Results : In the all 16 patients with preoperative CT images, higher attenuation was observed in the meningioma than in the brain parenchyma, and calcification was observed in 11 (69%). In 15 of the 21 patients (71%), a distinctive very low signal intensity appeared as a dark color in T2-weighted images. Nine of these 15 tumors (60%) exhibited heterogeneous enhancement, and 6 (40%) exhibited homogeneous enhancement that was unlike the homogeneous enhancing pattern shown by conventional meningiomas. Ten patients had a clear tumor margin without peritumoral edema. Conclusion : Although these peculiar radiological characteristics are not unique to sclerosing meningioma, we believe that they are distinctive features that may be helpful for distinguishing sclerosing meningioma from other subtypes.

• Journal of the korean society of oceanography
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• 제33권4호
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• pp.185-195
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• 1998

Two piston cores (94PC-2 and 95PC-4) taken from the East Sea (Sea of Japan) are studied to evaluate the paleoceanographic changes and its interaction with climatic variation. The bulk geochemistry of the non-biogenic fractions of 54 sediment samples is determined using X-ray fluorescence. Four geochemical stratigraphic units at both core sediments are recognized based on the variations in major element concentration. These chemical stratigraphic units correspond well with the sedimentological and paleontological facies. Source materials are considered as basic and/or intermediate rocks judging from silica content. A distinctive boundary around 11 kyr may correspond to Younger Dryas event. The switch of most major elements at this level and the distinctive changes in concentration of typical terrigenous elements (TiO$_2$ and Al$_2$O$_3$) are the strong evidence for the difference in sources of terrigenous materials. The weathering indices exhibit high degree in Core 94PC-2 and low degree in Core 95PC-4. The changes in weathering degree can be distinguished by the lowest value occurred at 11 kyr in Core 94PC-2 and by a gradual decrease from top to bottom in Core 95PC-4. The profiles of potassium and sodium exhibit specific excursions between the Holocene and the late Pleistocene. This implies that sediments of the two cores originating from different sources with different weathering degrees. The distinct two-group distributions in K$_2$O/CaO vs. Na$_2$O/K$_2$O also support the difference in provenance of aluminosilicate materials at the boundary of 11 kyr. Thus, supply patterns of terrigenous materials are stable in Holocene and more complicated in the last glacial period.