• 천문학회보
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• 제40권2호
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• pp.42.2-43
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• 2015

Massive stars play a major role in the interstellar energy budget and the shaping of the galactic environment. The water molecule is thought to be a sensitive tracer of physical conditions and dynamics in star-forming regions because of its large abundance variations between hot and cold regions. Herschel/HIFI allows us to observe the multiple rotational transitions of H2O including the ground-state levels, and its isotopologues toward high-mass star-forming regions in different evolutionary stages. Photodissociation regions (PDRs) are also targeted to investigate the distribution of water and its chemistry. We present line profiles and maps of H2O using data from two guaranteed-time key programs "Water In Star-forming regions with Herschel" and "Herschel observations of EXtra-Ordinary Sources". We analyze the temperature and density structures using LTE and non-LTE methods. We also estimate turbulent and expansion velocities, and abundance of water in the inner and outer envelopes using the 1D radiative transfer code. Around high-mass protostars we find H2O abundances of ~10-8-10-9 for the outer envelope and ~10-4-10-5 for the inner envelope, and expansion and turbulent velocities range from 1.0 km s-1 to 2.0 km s-1. The abundances and kinematic parameters of the sources do not show clear trends with evolutionary indicators. The Herschel/HIFI mapping observations of H2O toward the Orion Bar PDR show that H2O emission peaks between the shielded dense gas and the radicals position, in agreement with the theoretical and the observational PDR structure. The derived H2O abundance is ~10-7 and peaks at the depth of AV ~8 mag from the ionization front. Together with the low ortho-to-para ratio of H2O (~1) presented by Choi et al. (2014), our results show that the chemistry of water in the Orion Bar is dominated by photodesorption and photodissociation.

• 천문학회보
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• 제37권1호
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• pp.83.2-83.2
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• 2012

We have carried out simultaneous 22GHz $H_2O$ and 44GHz Class I $CH_3OH$ maser survey of 112 ultra-compact HII regions (UCHIIs) twice in 2010 and 2011. We detected $H_2O$ maser and $CH_3OH$ maser emission from 76(68%) and 49(44%) UCHIIs, respectively. Among them 15 $H_2O$ masers and 32 $CH_3OH$ masers are new detections. These high detection rates suggest that the occurrence periods of both masers are significantly overlapped with the UCHII phase. $CH_3OH$ masers always have small (<10 km s-1) relative velocities with respect to the natal molecular cores, while $H_2O$ masers often show larger velocities. We find 20 UCHIIs with $H_2O$ maser lines at relative velocities >30 km s-1. The formation and disappearance of $H_2O$ masers is frequent over one-year time interval. In contrast, $CH_3OH$ masers usually do not show substantial variation in intensity, velocity, or shape. The isotropic luminosities of both masers well correlate with the bolometric luminosities of the central stars when data points of lowand intermediate-mass protostars are added: $L_{H_2O}=5.89{\times}10^{-9}{(L_{bol})^{0.69}}$ and $L_{CH_3OH}=4.27{\times}10^{-9}{(L_{bol})^{0.62}}$. They also tend to increase with the 2cm radio continuum luminosity of UCHIIs and the 850 um continuum luminosity of the associated molecular cores. We discuss some individual sources.

• 치위생과학회지
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• 제20권2호
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• pp.97-106
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• 2020

Background: In Korea, laws for many medical technicians were revised in the Enforcement Decree of the Medical Technicians Act (MTA), which was announced on December 2018, whereas those related to dental hygienists remained unchanged. This study aimed to determine the awareness and opinions of dental hygienists regarding MTA. Methods: Dental hygienist were recruited as participants via convenient sampling in Seoul, Gyeonggi-do, and Chungcheong-do; data from 291 self-reported questionnaire responses were used for the final analysis. We investigated the participants' general characteristics, awareness, and request for the amendment of the MTA. The compliance with the work scope specified in the MTA and level of demand for revision of the MTA were analyzed by independent t-test and one-way analysis of variance. For all statistical analyses, the significance level was set at 0.05. Results: For the 2018 MTA revision, 99 (34.02%) knew that dental treatment assistance and surgery assistance were excluded, whereas 192 (65.98%) did not know. The item "The current medical technician law must be revised" was scored 4.13±0.80 out of 5 points, and significant differences were identified according to the education level, career, and position (p<0.05). The item "It is necessary to institutionalize the expanded work scope beyond the work scope of dental hygienists specified in the MTA" was scored 4.02±1.04 out of 5 points, and significant differences were identified according to age (p<0.05). Conclusion: The participants wanted the MTA to be revised to reflect the real-world work performed by dental hygienists in the dental clinical field. The legal system must ensure the legal protection of the work area of the dental hygienist as an oral health professional, and recognize the legal work scope of the dental hygienist.

• 방송공학회논문지
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• 제24권1호
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• pp.41-47
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• 2019

HEVC(High Efficiency Video Coding) 보다 뛰어난 압축 성능을 갖는 차세대 비디오 압축 표준으로 진행중인 VVC(Versatile Video Coding)에서는 보다 향상된 움직임 병합(Merge) 모드를 위한 기법들이 다루어지고 있다. 기존의 병합 모드에서는 다수의 주변 블록에서 움직임 정보가 존재하지 않으면 현재 블록의 움직임 정보로 사용할 병합 후보 리스트에 제로(zero) 움직임 벡터가 후보에 삽입될 수 있으며 이는 부호화 효율을 저하시킬 수 있다. 본 논문에서는 병합 후보 리스트에 제로 움직임 후보가 삽입되는 경우를 줄이기 위해 대체 움직임 정보를 생성하여 병합 후보 리스트에 삽입하는 효율적인 병합 모드 후보 리스트 구성 기법을 제시한다. 실험결과 제안 기법은 VTM1.0 대비 3% 복호화 복잡도 증가와 함께 0.2%의 부호화 성능 향상을 보였다.

• 한국화재소방학회:학술대회논문집
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• 한국화재소방학회 2008년도 추계학술논문발표회 논문집
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• pp.434-437
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• 2008

In this study, we developed a fuel moisture variation prediction model on each day after precipitation during a spring forest fire exhibition period. For this research, we selected plots in pine forest on Sam-Chuck si and Dong-hae si in Kangwon do according to a forest density(low, mediate, high) and classified a surface woody fuel by a diameter.(below 0.6cm, $0.6{\sim}3cm$, $3{\sim}6cm$, and above 6cm). A validity of this model was verified by applying a fuel moisture variation after precipitation in this spring. In the result, $R^2$ was $0.76{\sim}0.92$. This model will be a useful for improvement of a forest fire danger rate forcast through a prediction a fule moisture in forest.

• 한국항만경제학회지
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• 제29권3호
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• pp.1-23
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• 2013

본 연구는 1992년부터 2011년까지 월별자료를 사용하여 여러 가지 시계열 추정모델과 승법 계절 ARIMA 모형을 설정하여 부산항의 컨테이너 물동량을 추정하고 예측하였다. 여러 가지 모델로 추정한 결과 부산항의 컨테이너 물동량과 물동량 변동 모두 계절을 승법한 ARIMA 모델 $(1,0,1){\times}(1,0,1)_{12}$로 추정하였을 때, 추정결과와 Akaike information, Schwarz, Hannan-Quin 기준 등으로 보아, 가장 좋은 ARIMA 추정과 예측 모형으로 나타났다. 그리하여 부산항 물동량 추정의 최적모형인 ARIMA $(1,0,1){\times}(1,0,1)_{12}$ 모형에 의해 향후 8년간 96개월에 대한 부산항 물동량 미래 예측치(2013-2020년)를 월별로 추정하여 예측한 결과 2013년부터 부산의 물동량은 연도별로 조금씩 지속적으로 증가하는 추세를 보일 것으로 나타났다. ARIMA $(1,0,1){\times}(1,0,1)_{12}$ 모형에 의한 부산항의 컨테이너 물동량의 연도별 예측량은 2013년 1천 891만 TEU, 2014년 2천 34만 TEU, 2015년 2천 188만 TEU, 2016년 2천 353만 TEU, 2017년 2천 531만 TEU, 2018년 2천 722만 TEU 그리고 2020년 3천 148만 TEU 등으로 나타났다.

• 천문학회보
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• 제40권2호
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• pp.36.1-36.1
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• 2015

We present $5-14{\mu}m$ Infrared Spectrograph spectra of 14 T Tauri stars which show Polycyclic Aromatic Hydrocarbon (PAH) features and reside in 0.7 pc from ${\Theta}_1$ Ori C. The spectral types of nine out of 11 stars have spectral type information, with types ranging from K7-M5. These stars do not supply strong enough UV photons to excite PAH emission in their disks. Therefore, we consider the detection of PAH emission in disks around low mass stars illuminated by an external source of UV photons, namely, from Trapezium OB association, including ${\Theta}_1$ Ori C. The morphological features of PAH emission from most disks around K-M type host stars are unique, not belonging to any known classes of PAH features. We found that the PAH emission strengths decrease as the projected distance of the objects from ${\Theta}_1$ Ori C increase. We suggest future far-IR and submm/mm observations for better understanding of the characteristics and distribution of PAHs in these disks.

• 한국컴퓨터정보학회논문지
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• 제23권10호
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• pp.181-188
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• 2018

In this paper, we tried to investigate whether the influence of 'I' in a heterogeneous network of physical network and virtual network can be quantitatively measurable. To do this, we used Networked Community(NC) methodology to devise a concrete model of influence assessment in heterogeneous network. In order to test the model, we conducted an experiment with Donald J. Trump and his surroundings to evaluate the effectiveness of this influence assessment model. Experimentation included the measurement of impacts on the physical and virtual networks, and the impact on the networked community. Using Trump's case, we found that analyzing only one of the two networks can not accurately analyze the impact on others.

• International Journal of Contents
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• 제1권2호
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• pp.39-43
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• 2005

In this paper, we describe a generation mechanism of semantic-based queries for high accuracy information retrieval and question answering. It is difficult to offer the correct retrieval result because general information retrieval systems do not analyze the semantic of user's natural language question. We analyze user's question semantically and extract semantic features, and we .generate semantic-based queries using them. These queries are generated using the se-mantic-based question analysis grammar and the query generation rule. They are represented as semantic features and grammatical morphemes that consider semantic and syntactic structure of user's questions. We evaluated our mechanism using 100 questions whose answer type is a person in the TREC-9 corpus and Web. There was a 0.28 improvement in the precision at 10 documents when semantic-based queries were used for information retrieval.

• 환경정책연구
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• 제7권1호
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• pp.101-118
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• 2008

본 논문은 환경산업에 의한 노동수요 창출에 대해 알아보았다. 이를 위해 정부에서 발표하는 통계, 특히 환경부의 환경산업조사통계를 기초로 하여 오차항에 대한 다양한 가정을 통해 부분균형적인 단일 노동수요함수를 추정하여 보았다. 추정결과 환경산업의 환경부문 매출액 증가를 통한 노동수요 탄력도는 최소 0.193에서 최대 0.256에 해당하는 것으로 계산되어 각 산업별 환경기업들의 10억원의 매출증가를 통해 7.7에서 10.3명의 노동수요가 증가하는 것으로 계측되었다. 이는 특히 정부의 정책지원이 환경산업의 총매출액 1%에 해당하는 금액의 매출증가를 유도한다면 연간 $1,600{\sim}2,300$명의 직접 고용을 증대시키는 것으로 계측되었다. 그러나 안타깝게도 환경산업 노동력의 많은 부문이 단순노무직으로 구성되어 있어 향후 환경산업의 발전을 극대화하고 우리나라 경제성장의 중추 산업으로 육성하기 위해서는 정부의 기술개발과 수요증대에 대한 지속적인 지원이 필요하다 하겠다. 결국 이러한 정책적인 지원이 우리나라의 지속가능발전의 가능성을 극대화할 것이다.