• Journal of the Korean Geotechnical Society
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• v.20 no.9
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• pp.133-144
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• 2004

Pre-reinforcement ahead of a tunnel face using long steel or FRP (Fiberglass Reinforced Plastic) pipes in NATM(New Austrian Tunnelling Method), known as the RPUM(Reinforced Protective Umbrella Method) or UAM (Umbrella Arch Method), is the promising method to sustain the stability of a shallow tunnel face and reduce the ground settlements. In addition, horizontal reinforcing of the face is recently emphasized to improve the stability of the face. However, the characteristics on longitudinal arching around the face have not yet been established quantitatively with the RPUM (crown-reinforcing) and/or the face horizontal reinforcing. In this study, therefore, the behavior of cohesionless soil around the face reinforced by the reinforcing member representing the RPUM and horizontal reinforcing is investigated through two-dimensional laboratory model tests. A series of tests were carried out on various conditions by changing lengths and angles of the reinforcing members. Based on the vertical pressure around the face, the characteristics of longitudinal arching have been found for the case of the non-reinforced and the reinforced.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.12 no.4
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• pp.1-10
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• 2009

This study has intended to build ecological networks in consideration of life-zones inside Cheongju city through biotope grade, GIS network analysis etc. This study consisted of following three steps. First, we selected core districts and core spot districts using land use patten and biotope grade. The core district included the first grade of biotope and forest land. The core district consisted of two sectors : east axis core, Uam mountain; west axis core, Bumo mountain. The core spot district included the first grade of biotope. The core spot districts consisted of two sectors : north axis base core, Myongshim park; south axis base core, Guryong park. Second, the base district included the second grade of biotope and park and school. We used buffering analysis within 500m of the base district and selected the new base district. Third, we connected core districts and base core districts using least cost analysis of GIS. Thus we built comprehensive ecological networks in consideration of life-zones through GIS.

• Journal of Communications and Networks
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• v.16 no.2
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• pp.130-139
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• 2014

Due to the unpredictable nature of channel availability, carrying delay-sensitive traffic in cognitive radio networks (CRNs) is very challenging. Spectrum leasing of radio resources has been proposed in the so called coordinated CRNs to improve the quality of service (QoS) experienced by secondary users (SUs). In this paper, the performance of coordinated CRNs under fixed-rate with hard-delay-constraints traffic is analyzed. For the adequate and fair performance comparison, call admission control strategies with fractional channel reservation to prioritize ongoing secondary calls over new ones are considered. Maximum Erlang capacity is obtained by optimizing the number of reserved channels. Numerical results reveal that system performance strongly depends on the value of the mean secondary service time relative to the mean primary service time. Additionally, numerical results show that, in CRNs without spectrum leasing, there exists a critical utilization factor of the primary resources from which it is not longer possible to guarantee the required QoS of SUs and, therefore, services with hard delay constraints cannot be even supported in CRNs. Thus, spectrum leasing can be essential for CRN operators to provide the QoS demanded by fixed-rate applications with hard delay constraints. Finally, the cost per capacity Erlang as function of both the utilization factor of the primary resources and the maximum allowed number of simultaneously rented channels is evaluated.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.38 no.3
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• pp.247-257
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• 2001

New methods are proposed for printing a full resolution image on a limited output device. The proposed algorithm uses a dot-pattern database that models overlapping phenomena among neighbor printing dots. To solve the problem of dot-overlap, the gray levels of dot-pattern sets were calculated using a circular dot-overlap model and then measured by a spectrometer. Thereafter, in order to improve the visual quality of the color dithering, the contrast sensitivity function of the human visual system was used. As a result, the optimal dot-pattern can be selected from the database. Consequently, the proposed algorithm can produce high quality images while using low-cost color devices.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.10 no.1
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• pp.91-99
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• 2007

The research was carried out to define the morphological and growth characteristics of Poa pratensis L. (Kentucky bluegrass) 'Pureundul' native to Korea. Poa pratensis 'Pureundul' was collected from the belt highway around Mt. Uam located in Naedeok-dong, Cheongju City, Chungcheongbuk-do Province on May 5, 1995. The morphological characteristics of 'Pureundul' were compared with those of 205 individuals of native Poa pratensis collected throughout the nation from June 11, 2000 to June 21, 2003. The findings were as follows : The height of plant was 28.2cm but increased to 40.0cm at the flowering time. The height of first node from the base was 6.8cm and the length and width of leaf were 17.3cm and 2.9mm, respectively. The length of a spike was 7.9cm. Based on these morphological characteristics, 'Pureundul' was defined medium type Kentucky bluegrass. Visual quality(1~9), visual color and visual density were measured. The visual quality, color and density of 'Pureundul' were not superior to those of introduced species but above the average other native species. The damages from the diseases during summer resulted in poorer visual quality of color of 'Pureundul'. But the spread of the diseases was slower in 'Pureundul' than other native species, and accordingly 'Pureundul' didn't suffer from more quality deterioration from July to September during which the diseases broke out. Entering fall, 'Pureundul' showed high quality comparable to that of the introduced species. If 'Pureundul' is put to breeding by implementing pest control in summer and introducing disease tolerant genes, it will be used to make greens of greater quality than now.

• Journal of Advanced Navigation Technology
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• v.24 no.5
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• pp.348-357
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• 2020

An important challenge in commercialization of eVTOL PAV is to reduce noise for urban air mobility (UAM) operation. Therefore, in this paper, noise priority routes were created to minimize the number of people affected by noise using aviation environmental design tool (AEDT) software and population distribution data for administrative districts, and noise analyses during operation were performed. Also, it was analyzed how much noise exposure could be reduced compared to the number of people affected by noise in the shortest route. Considering that the eVTOL PAV developers do not provide data, the analysis was conducted using a helicopter model. As a result, it was shown that the noise priority route that minimized the amount of noise exposure was more efficient than other routes.

• Journal of the Korean Home Economics Association
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• v.45 no.2
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• pp.1-22
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• 2007

The purpose of this study was to investigate the effect of mother's characteristics, mediated by disciplinary methods and young children's emotional regulation, on young children's aggression. Subjects of this study consisted of 342 young children drawn from seven preschools in Cheongju city. The pilot study was used to examine the applicability of survey instrument. Data were analyzed by the method of frequency, percentage, Cronbach' ${\alpha}$, factor analysis, T-test. F-test, and Duncan post-hoc test using SPSSWIN program. The test of model was done with analysis of correlational matrix in LISREL VII package using a maximum likehood estimation. The results of this research were as follows: First, there were statistically significant differences in mother's characteristics consisting of neurosis symptom and extroversions, disciplinary methods consisting of coercive-punishment and indifferent-irresponsibility, young children's emotional regulation, and young children's aggression consisting of relation and overtness according to some socio-demographic variables. Girls had the higher emotional regulation than boys. Second, the direct effects of disciplinary methods and emotional regulation on boys' aggression were different in between relational and overt aggression. Third, the variables predicting boys' emotional regulation directly were the same in both relational and overt aggression. Forth, the direct effect of mother's characteristics on disciplinary methods was different in between coercive-punishment and indifferent-irresponsibility. Fifth, the indirect effects of mother's characteristics, mediated by disciplinary methods and young children's emotional regulation, on young children's aggression were partly supported in this study. Sixth, the theoretical model of the impact of mother's characteristics, disciplinary methods, and young children's emotional regulation on young children's aggression was different according to gender.

• Journal of Navigation and Port Research
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• v.29 no.10 s.106
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• pp.921-926
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• 2005

The purpose of this paper is to conduct a comparative analysis of container terminal operation in Busan and Kwangyang port. The research method used for this study is DEA(Data Envelopment Analysis} and among DEA methods CCR and BCC model has been used. According to the results of CCR model Gamman in 2004 and Gamcheon in 2004 are found to be the most efficient terminals in the sample and the inefficient terminals include Gwangyang Phase 2 terminal. Based on BCC model Gamcheon and Uam are identified as the most efficient terminals in three consecutive years including Gamman terminal in 2004. The inefficient terminals include New Gamman in 2002 and Hutchison in 2002. The research findings show that inefficient terminals need to fully utilise their terminal facilities and increase container throughput through effective marketing activities.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.31 no.2
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• pp.70-81
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• 2013

In this study, the locational and constructional characteristics of Jukrimseowon, pavilion Imrijeong, and Palgwaejeong located in Nonsan, Ganggyung-eup were reviewed and the interrelation of these three places were studied through references including records of those days; Sagyeyonbo(沙溪年譜), Jukrimseowon dorok(竹林書院都錄), Imrijeonggi(臨履亭記), Jukrimseowon Myojeongbi(竹林書院廟庭碑), Namyurok(南遊錄). The result is as follows. Jukrimseowon enshrining Yukhyeon(六賢) is arranged as 'Hongsalmoon-Woisalmoon-Dongjae(憲章堂; Heonjangdang)' and 'LIbrary-Naesammoon(神門; shin moon)-Sau(竹林祠: Jukimsa)', excluding a lecture hall. In case of Sagye Jangsang Kim's Imrijeong(沙溪金長生) and Uam Shiyoel Song(尤庵宋時烈)'s Palgwaejeong respectively constructed 50 meters and 10 meters each away from Jurimseowon, detail designs such as scale, roofs, surface, windows, doors, and tablets as well as its prospect are nearly identified. Especially Taking Imrijeong and Palgwaejeong's locational conditions composed of rocks centered on Jukrimseowon, those are maintain the bilateral symmetry as much as possible and surround the shrine. It appeared that the Jukrimseowon's shrine enshrining Yulgok(栗谷) and Ugye(牛溪) was rebuilt during the reconstruction of auditoriums because of political conditions after the renovation of Kiing Injo and it was called as 'Hwangsanseowon(黃山書院)' with Imrijeong which was a lecture hall. It was an inevitable consequence to keep the bilateral symmetry which is a basic order of auditorium structure by maintaining and using Imrijeong and Palgwaejeong as a lecture hall of the auditorium after the reconstruction at least. Consequently, the desperate attempt to adjust the arrangement and visual imbalance of Imrijeong built with periodical differences and Hwangsanseowon resulted from the construction of shrine was Palgwaejeong built under Monggoibyuk of Hwansan Taken these circumstances together, Jukrimseowon is a 'shrine-centered auditorium' with characteristics of auditorium, constructed by integrating Imrijeong which was used as a lecture hall after the construction of shrine and Palgwaejeong repaired through the reconstruction. The construction of Palgwaejeong and the formative conformity with Imrijeong are assumed as an consequence intended for the compensation of Jukrimseowon's function and role as an auditorium. This study will provide an opportunity to focus on the auditorium and pavilion's complementary function as well as the Confucian and constructional functions by revealing the fact that pavilions were established as a complementary facility for the lecture hall of auditorium.

• Journal of Environmental Science International
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• v.11 no.5
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• pp.419-436
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• 2002

The current paper reports on the enhancement of O$_3$, CO, NO$_2$, and aerosols during the Asian dust event that occurred over Korea on 1 May 1999. To confirm the origin and net flux of the O$_3$, CO, NO$_2$, and aerosols, the meteorological parameters of the weather conditions were investigated using Mesoscale Meteorological Model 5(MM5) and the TOMS total ozone and aerosol index, the back trajectory was identified using the Hybrid Single-Particle Lagrangian Integrated Trajectory Model(HYSPLIT), and the ozone and ozone precursor concentrations were determined using the Urban Ashed Model(UAM). In the presence of sufficiently large concentrations of NO$\sub$x/, the oxidation of CO led to O$_3$ formation with OH, HO$_2$, NO, and NO$_2$ acting as catalysts. The sudden enhancement of O$_3$, CO, NO$_2$ and aerosols was also found to be associated with a deepening cut-off low connected with a surface cyclone and surface anticyclone located to the south of Korea during the Asian dust event. The wave pattern of the upper trough/cut-off low and total ozone level remained stationary when they came into contact with a surface cyclone during the Asian dust event. A typical example of a stratosphere-troposphere exchange(STE) of ozone was demonstrated by tropopause folding due to the jet stream. As such, the secondary maxima of ozone above 80 ppbv that occurred at night in Busan, Korea on 1 May 2001 were considered to result from vertical mixing and advection from a free troposphere-boundary layer exchange in connection with an STE in the upper troposphere. Whereas the sudden enhancement of ozone above 100 ppbv during the day was explained by the catalytic reaction of ozone precursors and transport of ozone from a slow-moving anticyclone area that included a high level of ozone and its precursors coming from China to the south of Korea. The aerosols identified in the free troposphere over Busan, Korea on 1 May 1999 originated from the Taklamakan and Gobi deserts across the Yellow River. In particular, the 1000m profile indicated that the source of the air parcels was from an anticyclone located to the south of Korea. The net flux due to the first invasion of ozone between 0000 LST and 0600 LST on 1 May 1999 agreed with the observed ground-based background concentration of ozone. From 0600 LST to 1200 LST, the net flux of the second invasion of ozone was twice as much as the day before. In this case, a change in the horizontal wind direction may have been responsible for the ozone increase.