• Journal of Astronomy and Space Sciences
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• 제20권2호
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• pp.123-132
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• 2003

1995년 11월부터 1999년 12월까지 총 10일간 W형 접촉쌍성 AB And를 소백산천문대의 61cm 망원경과 BVR필터를 사용하여 CCD 측광관측을 수행하였다. 우리의 관측으로부터 AB And의 1995, 1996그리고 1999년에 걸친 년도별 광도곡선을 완성하였고, 8개의 새로운 극심시각을 결정하였다. 새로 얻은 광도곡선은 AB And가 지난 5년 동안 심한 광도변화를 겪어왔음을 보여주고 있다. 기준 광도곡선으로 선정된 1996년의 광도곡선을 Wilson-Devinney쌍성모델의 접촉모드에 적용하여 AB And의 측광해를 구하였다. 이 분석에서 광도변화의 원인을 흑점에 의한 것으로 가정하여 시스템 인자들을 산출한 후, 단지 흑점만을 조정인자로 하여 1995년과 1999년 광도곡선을 분석하였다. 그 결과, 우리는 광도변화가 반성 표면 위에 hot spot과 cool spot가 동시에 존재해서 일어난다고 해석하였다. 반성 표면 위의 hot spot는 이재우(1999)가 제안한 질량교환에 의한 것으로 유추할 수 있다.

• Journal of Astronomy and Space Sciences
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• 제21권2호
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• pp.73-82
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• 2004

Samec et al.(1997)의 UBV 광도곡선과 Lu ＆ Rucinski(1999)의 시선속도곡선을 2003년에 개정한 Wilson-Devinney 쌍성모델을 적용하여 W형 과접촉쌍성 V417 Aql의 측광 및 분광학적 해를 새롭게 산출하였다. 광도곡선 분석에서 Qian(2003)이 제안한 제3천체의 광도를 광도곡선 분석에서 고려한 결과, 삼체의 광도가 U, B, V 필터에서 각각 2.7%, 2.2%, 0.4% 존재하고, 삼체의 광도를 고려한 경우가 그렇지 않은 경우보다 이론치와 관측치가 극심 부근에서 더 잘 일치하였다. 우리의 해로부터 V417 Aql의 절대 물리량을 $M_1$= 0.53 $M_{ }$, $M_2$= 1.45 $M_{*}$, $R_1$= 0.84 $R_{*}$, 그리고 $R_2$= 1.31 $M_{*}$으로, 거리를 216pc으로 산출하였다. 우리가 구한 거리는 Rucinski ＆ Duerbeck(1997)의 관계식 $M_{v}$ = $M_{v}$(log P, B-V)으로부터 계산한 거리(204pc)와 잘 일치하는 반면, Hipparcos 삼각시차에 의한 거리(131$\pm$40pc)보다 멀다. 그 차이는 Hipparcos 시차의 비교적 큰 오차 때문에 생긴 것일 수 있다. 수 있다.

• Asian-Australasian Journal of Animal Sciences
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• 제30권7호
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• pp.1054-1060
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• 2017

Objective: This study was aimed at evaluating effects of cattle breed resources and alternative mixed-feeding practices on meat productivity and emission intensities from household farming systems (HFS) in Daklak Province, Vietnam. Methods: Records from Local $Yellow{\time}Red$ Sindhi (Bos indicus; Lai Sind) and 1/2 Limousin, 1/2 Drought Master, and 1/2 Red Angus cattle during the growth (0 to 21 months) and fattening (22 to 25 months) periods were used to better understand variations on meat productivity and enteric methane emissions. Parameters were determined by the ruminant model. Four scenarios were developed: (HFS1) grazing from birth to slaughter on native grasses for approximately 10 h plus 1.5 kg dry matter/d (0.8% live weight [LW]) of a mixture of guinea grass (19%), cassava (43%) powder, cotton (23%) seed, and rice (15%) straw; (HFS2) growth period fed with elephant grass (1% of LW) plus supplementation (1.5% of LW) of rice bran (36%), maize (33%), and cassava (31%) meals; and HFS3 and HFS4 computed elephant grass, but concentrate supplementation reaching 2% and 1% of LW, respectively. Results: Results show that compared to HFS1, emissions ($72.3{\pm}0.96kg\;CH_4/animal/life$; least squares $means{\pm}standard$ error of the mean) were 15%, 6%, and 23% lower (p<0.01) for the HFS2, HFS3, and HFS4, respectively. The predicted methane efficiencies ($CO_2eq$) per kg of LW at slaughter ($4.3{\pm}0.15$), carcass weight ($8.8{\pm}0.25kg$) and kg of edible protein ($44.1{\pm}1.29$) were also lower (p<0.05) in the HFS4. In particular, irrespective of the HSF, feed supply and ratio changes had a more positive impact on emission intensities when crossbred 1/2 Red Angus cattle were fed than in their crossbred counterparts. Conclusion: Modest improvements on feeding practices and integrated modelling frameworks may offer potential trade-offs to respond to climate change in Vietnam.

• Journal of Forest and Environmental Science
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• 제30권2호
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• pp.233-242
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• 2014

Estimating above-ground biomass is important in establishing an applicable methodology of Measurement, Reporting and Verification (MRV) System for Reducing Emissions from Deforestation and Forest Degradation-Plus (REDD+). We developed an estimation model of diameter at breast height (DBH) from IKONOS-2 image that led to above-ground biomass estimation (AGB). The IKONOS image was preprocessed with dark object subtraction and topographic effect correction prior to watershed segmentation for tree crown delineation. Compared to the field observation, the overall segmentation accuracy was 64%. Crown detection percent had a strong negative correlation to tree density. In addition, satellite-based crown area had the highest correlation with the field measured DBH. We then developed the DBH allometric model that explained 74% of the data variance. In average, the estimated DBH was very similar to the measured DBH as well as for AGB. Overall, this method can potentially be applied to estimate AGB over a relatively large and remote tropical forest in Northern Borneo.

• 천문학회지
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• 제53권2호
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• pp.43-48
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• 2020

We report an analysis of two poorly studied eclipsing binary stars, GSC 04396-00605 and GSC 04395-00485 (recently named V455 Dra and V454 Dra, respectively). Photometric data of the two stars were obtained using the 1-m Korean telescope of the LOAO operated by KASI while monitoring the cataclysmic variable DO Dra in the frame of the Inter-Longitude Astronomy (ILA) project. We derived periods of 0.434914 and 0.376833 days as well as initial epochs JD 2456480.04281 and JD 2456479.0523, respectively, more accurate than previously published values by factors 9 and 6. The phenomenological characteristics of the mean light curves were determined using the New Algol Variable (NAV) algorithm. The individual times of maxima/minima (ToM) were determined using the newly developed software MAVKA, which outputs accurate parameters using "asymptotic parabola" approximations. The light curves were approximated using phenomenological and physical models. In the NAV algorithm, the phenomenological parameters are well determined. We derived physical parameters using the Wilson-Devinney model. In this model, the best-fit parameters are highly correlated, thus some of them were fixed to reasonable values. For both systems, we find evidence for the presence of a cool spot and estimate its parameters. Both systems can be classified as overcontact binaries of EW type.

• 대한간호학회지
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• 제50권2호
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• pp.178-190
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• 2020

Purpose: The purpose of this study was to identify trends of nursing concept development in Korean journal papers to improve accurate understanding of nursing concepts. Methods: A systematic review of 216 concept development articles published from 1970 to 2018 that met the inclusion criteria was conducted using Research Information Sharing Service (RISS) databases. Results: The most common method of concept development was Walker and Avant's concept analysis method, identified in 139 (64.3%) of the 216 studies, followed by 48 examples of hybrid models (22.2%) and 15 examples of evolutionary methods (6.9%). Chinn and Kramer's method, Norris's clarification, Wilson's method, and others were also used. The concepts of "spirituality" and "fatigue" were most frequently analyzed. Among the 139 studies that used Walker and Avant's concept analysis method, 127 studies (91.4%) applied all the recommended steps; the others applied the recommended steps partially, omitting description of model cases/additional cases, antecedents/consequences, and empirical indicators. Among the studies using the hybrid model, among two (5.7%) did not describe attributes, three (8.5%) did not provide definitions, and 16 (45.7%) did not present empirical indicators in the final stage. Conclusion: Among concept development studies published in Korean journals, Walker and Avant's concept analysis method is most commonly used. In case of most studies using Walker and Avant's method a suitable concept analysis process is applied, but in case of other studies using the other concept development method, a suitable concept analysis process is not applied. Therefore, a suitable concept analysis process must be applied for concept development in nursing research.

• 천문학회보
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• 제36권2호
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• pp.141.1-141.1
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• 2011

New CCD BVR light curves of BD And are presented. Our light curves with nearly equal depths for both primary and secondary eclipses show well-defined photometric waves outside eclipse for all of BVR bandpasses. The orbital period is greatly revised as $0.^d92580519$ which is twice longer than that known previously. Sixteen timings from our observations and thirteen ones from the SuperWASP measurements were calculated. All available timings over 76 years, including ours, were analyzed to figure out the dynamical behavior of the system. It was found that the recent CCD O-C residuals varied in a cyclical way with a period of $9.^y18$ and a semi-amplitude of $0.^d0046$. The secondary period of $9.^y18$ is the most shortest one among those which have been ever found in the short period RS CVn binary stars. The periodic variation most likely arises from the light-travel time effect due to a low-mass ($m_3{\sim}0.88\;M_{\odot}$) tertiary companion moving in an orbit with an large eccentricity ($e_3$=0.70) and a low inclination ($i_3{\sim}28^{\circ}$). The Applegate mechanism could not operate properly in both components because the model parameters require too much large luminosity changes of ${\Delta}L/L_{p,s}$ > 10. The new light curves were synthesized using the 2003 version of Wilson-Divinney code. It was found useful to model two huge spots on the surface of the hotter star and a third-light in order to minimize the residuals from the observations. Astronomical basic parameters were deduced from our photometric solution.

• 여성건강간호학회지
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• 제28권3호
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• pp.187-196
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• 2022

Purpose: The purpose of this study was to investigate factors related to the levels of health-related quality of life (HRQoL) in elderly women based on Wilson and Cleary's HRQoL model. Methods: This study analyzed data from the eighth Korea National Health and Nutrition Examination Survey 2019 on 868 women over the age of 65 years. Based on the HRQoL model, parameters were categorized as personal, environmental, and physiological characteristics; symptom status; functional status; and perception of health status. The data were analyzed by quantile regression. Results: The overall level of HRQoL was 0.87. Factors related to HRQoL in the 10% quantile were higher education level, higher economic status, economic activity, more walking days, fewer diseases, lower stress, less activity limitation, and higher perceived health status. Factors related to the 25% quantile of HRQoL were more walking days, fewer diseases, less activity limitation, and higher perceived health status. Factors related to the 50% quantile were age, economic activity, more walking days, fewer disease, lower stress, less activity limitation, and higher perceived health status. Factors related to the 75% quantile of HRQoL were smoking, more walking days, fewer diseases, lower stress, less activity limitation, and higher perceived health status. Conclusion: While differing parameters were identified according to the level of HRQoL of elderly women in Korea, there were five common factors. Interventions that focus on increasing walking, mitigating diseases, stress, and activity limitations, and improving perceived health status can improve HRQoL.

• 한국환경복원기술학회지
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• 제18권6호
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• pp.135-149
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• 2015

Korean fir(Abies koreana E.H.Wilson 1920), endemic tree species of Korean peninsula, is considered as vulnerable and endangered species to recent rapid environmental changes such as land use and climate change. There are limited activities and efforts to find natural habitats of Korean fir for conservation of the species and habitats. In this study, by applying SDMs (Species Distribution Models) based on climate and topographic factors of Korean fir, we developed Korean fir's predicted distribution model and explored novel natural habitats. In Mt. Shinbulsan, Youngnam region and Mt. Songnisan, we could find korean fir's two novel habitat and the former was the warmest($13^{\circ}C$ in annual mean temperature), the driest(1,200mm~1,600mm in annual rainfall) and relatively low altitude environment among Korean fir's habitats in Korea. The result of SDMs did not include mountain areas of Gangwon-do as habitats of A. nephrolepis, because there were different contributions of key habitat environment factors, summer rainfall, winter mean temperature and winter rainfall, between A. koreana and A. nephrolepis. Our results raise modification of other distribution models on Korean fir. Novel habitat of Korean fir in Mt. Shinbulsan revealed similar habitat affinity of the species, ridgy and rocky site, with other habitats in Korea. Our results also suggest potential areas for creation of Korea fir's alternative habitats through species reintroduction in landscape and ecosystem level.

• Journal of Astronomy and Space Sciences
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• 제32권2호
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• pp.127-136
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• 2015

We present a by-product of our long term photometric monitoring of cataclysmic variables. 2MASS J18024395 +4003309 = VSX J180243.9 +400331 was discovered in the field of the intermediate polar V1323 Her observed using the Korean 1-m telescope located at Mt. Lemmon, USA. An analysis of the two-color VR CCD observations of this variable covers all the phase intervals for the first time. The light curves show this object can be classified as an Algol-type variable with tidally distorted components, and an asymmetry of the maxima (the O'Connell effect). The periodogram analysis confirms the cycle numbering of Andronov et al. (2012) and for the initial approximation, the ephemeris is used as follows: Min I. BJD = 2456074.4904+0.3348837E. For phenomenological modeling, we used the trigonometric polynomial approximation of statistically optimal degree, and a recent method "NAV" ("New Algol Variable") using local specific shapes for the eclipse. Methodological aspects and estimates of the physical parameters based on analysis of phenomenological parameters are presented. As results of our phenomenological model, we obtained for the inclination $i=90^{\circ}$, $M_1=0.745M_{\odot}$, $M_2=0.854M_{\odot}$, $M=M_1+M_2=1.599M_{\odot}$, the orbital separation $a=1.65{\cdot}10^9m=2.37R_{\odot}$ and relative radii $r_1=R_1/a=0.314$ and $r_2=R_2/a=0.360$. These estimates may be used as preliminary starting values for further modeling using extended physical models based on the Wilson & Devinney (1971) code and it's extensions