• Journal of the Korean Wood Science and Technology
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• v.43 no.2
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• pp.274-285
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• 2015

In view of the environmental and health hazards posed by synthetic insecticides, the use of plant products as botanical insecticides has gained increasing in recent years. In this study, we reported the insecticidal activity of extracts isolated from Coptis chinensis. On crude extraction, among the various solvent types tested (water, 1% (w/v) of sodium hydroxide, 70% ethanol), the 70% ethanol extract showed the best insecticidal activity (36.5%). Three different fractions (n-hexane, chloroform and ethyl acetate) were obtained from crude extract (70% ethanol) of the chloroform fraction and found to have noteworthy insecticidal activity (62.9%) by filter paper contact bioassay. Their chemical structures were identified as 2-methoxy-4-vinylphenol and aniline by head space-GC-MS analysis. Both compounds displayed a dose-dependent insecticidal activity of Myzus persicae (Sulzer). Insecticidal activity at the lowest concentration tested (500 ppm) approached 85.4% in the aniline compared with 79.9% in the 2-methoxy-4-vinylphenol. The insecticidal activity was greater for the aniline than 2-methoxy-4-vinylphenol. It is believed that the insecticidal activity is due mainly to the presence of aniline.

• Journal of Astronomy and Space Sciences
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• v.30 no.4
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• pp.231-239
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• 2013

To identify seasonal and latitudinal variations of F2 layer during magnetic storm, we examine the change of daily averages of foF2 observed at Kokubunji and Hobart during high (2000~2002) and low (2006~2008) solar activity intervals. It is found that geomagnetic activity has a different effect on the ionospheric F2-layer electron density variation for different seasons and different latitudes. We, thus, investigate how the change of geomagnetic activity affects the ionospheric F2-layer electron density with season and latitude. For this purpose, two magnetic storms occurred in equinox (31 March 2001) and solstice (20 November 2003) seasons are selected. Then we investigate foF2, which are observed at Kokubunji, Townsville, Brisbane, Canberra and Hobart, Dst index, Ap index, and AE index for the two magnetic storm periods. These observatories have similar geomagnetic longitude, but have different latitude. Furthermore, we investigate the relation between the foF2 and the [O]/[$N_2$] ratio and TEC variations during 19-22 November 2003 magnetic storm period. As a result, we find that the latitudinal variations of [O]/[$N_2$] ratio and TEC are closely related with the latitudinal variation of foF2. Therefore, we conclude that the seasonal and latitudinal variations of foF2 during magnetic storm are caused by the seasonal and latitudinal variations of mean meridional circulation of the thermosphere, particularly upwelling and downwelling of neutral atmosphere during magnetic storm.

• Monthly Notices of the Royal Astronomical Society
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• v.491 no.3
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• pp.4045-4056
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• 2020

We examine whether galaxy environments directly affect triggering nuclear activity in Sloan Digital Sky Survey (SDSS) local spiral galaxies using a volume-limited sample with the r-band absolute magnitude M_r < -19.0 and 0.02 <z< 0.055 selected from the SDSS Data Release 7. To avoid incompleteness of the central velocity dispersion σ of the volume-limited sample and to fix the black hole mass affecting AGN activity, we limit the sample to a narrow σ range of 130 km s^-1 <σ< 200 km s^-1. We define a variety of environments as a combination of neighbour interactions and local density on a galaxy. After the central star formation rate (which is closely related to AGN activity level) is additionally restricted, the direct impact of the environment is unveiled. In the outskirts of rich clusters, red spiral galaxies show a significant excess of the AGN fraction despite the lack of central gas. We argue that they have been pre-processed before entering the rich clusters, and due to mergers or strong encounters in the in-fall region, their remaining gases efficiently lose angular momentum. We investigate an environment in which many star-forming galaxies coexist with a few starburst-AGN composite hosts having the highest [O_III] luminosity. We claim that they are a gas-rich merger product in groups or are group galaxies in-falling into clusters, indicating that many AGN signatures may be obscured following the merger events.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.1
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• pp.83.2-83.2
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• 2015

The Goheung radio interferometer with three 1.8-m antennas has been installed at National Youth Space Center in Goheung, Korea. The interferometric observation of the Sun using the Goheung radio interferometer was carried out and the observed data was analysed to construct the radio contour map of the Sun in 2014. The specifications of Goheung radio interferometer and the synthesized interferometer map of the Sun are provided. As a science activity center for youth, we currently provide students some experimental activities based on the principle of radio observation and interferometer. Our goal is to encourage youth to be interested in astronomy by engaging real experience of radio observation and constructing a synthesized interferometer map with observed data.

• International Journal of Advanced Culture Technology
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• v.8 no.1
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• pp.199-206
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• 2020

I suggested the design learning environment based on affordance concept approach for supporting and improving learners' behavior and outcome for convergent design education in this study. The design learning space should be applied teaching and learning activity, especially learners' behavior, physical space condition to support the design thinking process. The design learning space needs openness, individuality and connectivity to support the learners' behavioral to immerse, participate, cooperate, understand, think and fulfill the design thinking process. The composition principles of the learning environment for convergent design education supports communication and collaboration among members for independence and interaction. The spaces for design research and teaching needs high privacy while facilitating visual communications through special materials and wall structure design. Also, for connectivity to improve the learners' physical and visual contact, the environment of the classrooms requires flexibility and mobility by providing an open space integrating unit cells for realizing learning purpose. These are provided by formed of an open structure for inducing visual communication and physical contact to involve the design activities and the mutual interchange.

• Journal of Korea Game Society
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• v.9 no.4
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• pp.33-43
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• 2009

The Digital Space that is generated by combining the development of computer technology with the imagination of utopia is entering upon the new phase no more playground than the space of creation. This study focused on the persona of digital space included the digital game and the virtual world. This paper compared with the persona formation processes -creation, activity, death phase- and interpreted the distinctive features of digital game and virtual world. This is a valuable study for avatar design in digital game and virtual world.

• Journal of Korea Multimedia Society
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• v.13 no.12
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• pp.1778-1785
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• 2010

This paper proposes a new video-based method of analyzing human gait which is a highly variable dynamic process. It captures a human gait of varying directions as a trajectory in the phase space. The proposed method includes two options of a stochastic process model and a self-organizing feature map as the tool of feature space representation and analysis. Test results show that the model is highly intuitive and we believe it can contribute to our understanding of human activity as well as gait behavior.

• Journal of the Korean housing association
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• v.13 no.3
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• pp.33-43
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• 2002

The purpose of this paper is to develop a space program of the new community center in multi-family housing. The community center defined in this study is a communal facility which integrate cultural and welfare facilities and activity programs into a complex. Through the analysis of the community programs and spaces for multi-family housing community, a new community center program is proposed. And basic area guidelines are proposed through the making of the space modelling of the important area of the center. According to the guidelines, more spaces compared to the present standards and conditions are needed for a new community center. However, the adjustment of area regulation is essential, considering the fast changing trend of resident's social needs. A new regulation system that controls the total area of function spaces of a community center, rather than controlling each function and area, is required. This kind of system makes it possible to decide programs freely within the limit of total floor area regulation by neighborhood's characteristics and residents'preference.

• Korean Journal of Human Ecology
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• v.6 no.2
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• pp.173-185
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• 1997

This study intends to suggest the considerations in the planning of production space of rice farming houses, based on their needs on the space and machinery for rice production. The 30 rice farming houses, in a village in Chungbuk province, responded for this study. Larger stalls and new built storehouses for grain or machinery showed changes in attached buildings after 1970s. Despite of the broad use of machinery in rice terming, however, only 1 or 2 houses in a village own and run it, and the planning of storehouse for machinery has to be done respectively. The sort and location of attached houses depend on the scale of rice farming. And because the production activities in the riceplanting or harvesting period collide with household ones, the considerations on the planning of efficient activity-oriented production space are offered in this study.

• Journal of The Korean Digital Architecture Interior Association
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• v.4 no.1
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• pp.10-16
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• 2004

Territory is determined by physical elements that provide the occupants an obvious boundary in a space. The creation of boundary is a interpersonal process by which a person or group regulates interactions with others. The perception of territory needs boundary regulations that mean the composition of horizontal and vertical elements in architectural space. The perception of territory can be defined as perceptual reaction considering not only visual perception on the physical elements in the architectural space and also various kinds of social activity in architectural environment. To achiever territory in architectural space, visible and invisible boundary regulation should be need. It means that territorial boundary regulation needs visual and audial boundary regulation as well as spatial boundary regulation.