• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.4
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• pp.764-771
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• 2005

As high-speed class broadband communication services have come in earnest broadband communication services are well regularized, utilizing not only wire but also wireless. One of wireless communication systems named B-WLL system, which provides high-speed broadband communication services, gives users inconvenience because it utilizes wire in the service area. In order to overcome this drawback, local wireless construction with ubiquitous environment has been considered in a new service demand area. We bring forth a scheme of cell Planning with 2 GHz frequency for wireless LAN construction which provides connection and mobility with no restrictions in time and locations.

• Journal of Korean Society for Atmospheric Environment
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• v.16 no.6
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• pp.585-594
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• 2000

Through an application of Micrometerorological methods, we conducted measurements of Hg fluxes from Nan-Ji-Do which is well known as one of the major local areal sources in Seoul metropolitan area during Match/April of 2000. In the course of our study, we determined the concentration gradients of total gaseous Hg(between 20 and 2000 cm heights) and combined these data with Micrometerorological components to derive is fluxes. It turned out that emission from and dry deposition to soil surfaces occurred at the ratio of 72:27 from a total of 271 hourly measurements. The validity of measured concentration gradients( or resulting fluxes) was evaluated in terms of percent gradient. Accordingly, about more than 95% of gradient data derived were statistically significant. The mean fluxes of Hg across soil-air interface, when computed using the concentrations gradients and relevant parameters, were found at 253(during emission) and -846ng/$m^2$/h(during dry deposition) The occurrences of abnormalously high exchange rates appear to be the combined effects of enormously high gradient values and high transfer coefficients. While the emissions of Hg occurred constantly during the whole study periods, the occurrences of dry deposition events were observed most intensively during very limited time periods(3/29 and 4/3). The results of our study cleary indicated that the studied area is a strong local areal source, while exhibiting great potential as a major sink simultaneously.

• International Journal of Aeronautical and Space Sciences
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• v.5 no.1
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• pp.94-100
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• 2004

Ionospheric time delay is the biggest error source for single-frequency DGPSapplications, including time transfer and Wide Area Differential GPS (WADGPS).Currently, there are many attempts to develop real-time ionospheric time delayestimation techniques to reduce positioning error due to the ionospheric time delay.Klobuchar model is now widely used for ionosphehc time delay calculation forsingle-frequency users. It uses flat surface at night time and cosine surface atdaytime[1], However, the model was developed for worldwide ionosphere fit, it isnot adequate for local area single-frequency users who want to estimateionospheric time delay accurate1y[2]. Therefore, 3-D ionosphere model usingtomographic estimation has been developed. 3-D tomographic inversion modelshows better accuracy compared with prior a1gorithms[3]. But that existing 3-Dmodel still has problem that it requires many coefficients and measurements forgood accuracy. So, that algorithm has Umitation with many coefficients incontinuous estimation at the small region which is obliged to have fewermeasurements.In this paper, we developed an modified 3-D ionosphehc time delay modelusing tomography, which requires only fewer coefficients. Because the combinationsof our base coefficients correspond to the full coefficients of the existing model, ourmodel has equivalent accuracy to the existing. We confirmed our algorithm bysimulations. The results proved that our modified algohthm can perform continuousestimation with fewer coefficients.

• Journal of Environmental Science International
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• v.14 no.7
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• pp.629-637
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• 2005

Polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) were investigated in soil and pine needle samples taken from 16 sites of industrial and residential areas in Changwon, Korea to assess their distribution levels and to suggest the influence of industrial activities, PCDDs/DFs levels in the soil samples ranged from 0.57 to 20.79 pg I-TEQ/g dry weight with a mean value of 4.20 pg I-TEQ/g dry weight. PCDDs/DFs levels in the pine needle samples ranged from 0.39 to 8.75 pg I-TEQ/g dry weight with a mean value of 4.09 pg I-TEQ/g dry weight. In both soil and pine needle samples, the PCDDs/DFs concentrations in the industrial area sites were higher than those in the residential area sites. Homologue profiles in pine needle samples showed different patterns compared with soil samples. Based on the results of principal component analysis (PCA), it was confirmed that pine needles reflected a direct influence from local potential sources of PCDDs/DFs, showing a much higher degree of reflection than in soils. Pine needles are very useful as an indicator for monitoring or estimating the contamination of PCDDs/DFs in other areas which have been impacted by point pollution sources.

• Journal of the Korean housing association
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• v.18 no.2
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• pp.105-112
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• 2007

This research has been implemented based on the area of #369 Dowon-dong, Dalseo-gu, Dae-gu which is considered as a place with satisfactory characteristics for the flow of fresh air into the city. Simulations of the target area both prior to the development plan and after apartment complex blocking were analyzed in regard to blocking planning and pilotis based on the main direction of wind, $90^{\circ}$ (east wind) and $180^{\circ}$ (south wind). In addition, congested wind corridor flow in the target place was identified through a pollution spread simulation according to the wind corridor. Therefore, the flow of wind in the one area is affected by the blocking of the complex and the main direction of the wind. Also blocking, in regard of pilotis, provides a better flow of wind. This study was implemented based on wind formation by apartment complex planning, so further study on the other factors affecting the flow of a wind corridor along with block planning and pilotis need to be carried out. Sustainable environmental factors through analysis of the environmental factors have to be analyzed. Moreover, building and complementing fundamental resources and systematic devices should be supported.

• Korean Institute of Interior Design Journal
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• v.21 no.6
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• pp.121-128
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• 2012

This study is designed to find out the difference of life satisfaction and depression between urban and rural elderly. The research method is a questionnaire that surveys those aged 60 and older. The collected data were analyzed by categorizing them into two groups, 503 residing in the elderly who live in Daejeon city and 676 in those who live in Chungnam area. The result of analysis indicated that; First, life satisfaction of the urban elderly was higher than that of the rural elderly(t=3.67, p<.001). But depression between the two groups, the elderly who live in urban area and those who live in rural area, did not show a statistically significant difference. Second, the factors influencing the life satisfaction of urban elderly were convenience of housing, economic level, health status, local safety, life attitude, and period of residence. Third, the depression of urban elderly significantly related to health status, life attitude, economic level, age, and convenience of housing. Fourth, the factors influencing the life satisfaction of rural elderly were health status, economic level, convenience of housing, local safety, life attitude, type of residence, and period of residence. Fifth, the depression of rural elderly significantly related to health status, life attitude, and economic level.

• Journal of Wetlands Research
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• v.4 no.2
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• pp.57-66
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• 2002

The local storm occurred Nakdong river basin from August 4 to 11 of the year 2002, resulting in a record 500-600mm rainfall. The heavy rain continued for more than 10 days and especially between 3 to 4 am of August 9, 50mm per hour local storm occurred in Hanrim-myun area, Kimhae. 8 days after the storm, the water level of Nakdong river rose rapidly and the river flowed backward the branches. T he draining of the protected low wetland was unable and the water level of the inner bank area rose suddenly, causing the inundation in several areas. Baeksan bank of Nam river, Gahyun(Samhak) bank of Hwang river, and Kwangam bank of Shinban river, where the draining facilities were under construction or constructed recently, were failed by the piping around the draining culvert. This study analyze the cause of the damage in Nakdong river banks and suggests the countermeasures for future improvement. The damaged spot of the river bank was surveyed, and the rainfall and the fluctuation in the water levels were reviewed. Finally for the flood inundation prevention at the inner bank area, new floodplain management plan as the protect of low wetland established.

• Structural Engineering and Mechanics
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• v.84 no.2
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• pp.269-283
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• 2022

In this paper, a particular type of all-steel HSS brace members with a locally reduced cross-sectional area was experimentally and numerically investigated. The brace member was strengthened against local buckling with inner and outer boxes in the reduced area. Four single-span braced frames were tested under cyclic lateral loadings. Specimens included a simple steel frame with a conventional box-shaped brace and three other all-steel reduced section buckling-restrained braces. After conducting the experimental program, numerical models of the proposed brace were developed and verified with experimental results. Then the length of the proposed fuse was increased and its effect on the cyclic behavior of the brace was investigated numerically. Eventually, the brace was detailed with a fuse-to-brace length of 30%, as well as the cross-sectional area of the fuse-to-brace of 30%, and the cyclic behavior of the system was studied numerically. The study showed that the proposed brace is stable up to a 2% drift ratio, and the plastic cumulative deformation requirement of AISC (2016) is easily achieved. The proposed brace has sufficient ductility and stability and is lighter, as well as easier to be fabricated, compared to the conventional mortar-filled BRB and all-steel BRB.

• Journal of Environmental Science International
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• v.32 no.9
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• pp.647-657
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• 2023

The study analyzes the forest status of each local government for Korean forests and believes that it can be used as basic data for setting the direction pursued by each local government. The study took into account the fact that the forest rate in Korea was 63.5%, because it was judged that the higher the proportion of forest area, the more important it was to use the characteristics of forests. The characteristics of forests were analyzed based on four factors in 12 factors to identify the location of the ground body by dividing seven types. In addition, basic information on carbon absorption sources was provided by grasping the ability of carbon absorption sources per year through the amount of forest resources to be analyzed. In addition, as a result of analyzing the characteristics of the weather for the promotion of carbon absorption sources, the flat area on the side of Gangneung Mountain was a warm forest with a warm index of 106.0.

• The Journal of the Korea Contents Association
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• v.18 no.2
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• pp.450-458
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• 2018

The purpose of this study is to investigate the impact of university knowledge capital on the local business activity in the Korean local governments in the year 2015. We found that the increase of the standard deviation of university patent, scientific publications, incumbent firms, and industrial property rights raised the number of new knowledge-intensive firms to 15%, 11%, 54%, and 22%, respectively, in the local economy. In addition, the coefficient which reflects the interaction effects of the knowledge capital between universities and local industries was significant in the given area in the year. On the other hand, in the control variables, the coefficients for the size of local government, population density, and percentage of 20s~40s out of the total population in the local government were significant, showing above 90% level except for the variable of the distance between a local government and Seoul. In particular, when the knowledge capital of the university and industry coexists, the synergistic effect which has influence on the foundation of knowledge-intensive firms was meaningful despite the small scale, and these two types of knowledge capital could be complementary in creating new knowledge-intensive firms in the Korean local economy.