• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.8
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• pp.5369-5377
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• 2014

Korean pagodas were constructed in the shape of a wood pagoda, brick pagoda, stone pagoda, etc. On the other hand, the currently remaining traditional pagodas are those having nonflammable materials, such as brick, stone, etc. Compared to the stone pagoda, there is data regarding brick pagodas, but there is little literature data on how to construct these pagodas. This appears to be because there are relatively few Korean brick pagodas currently remaining, they are locally restricted, the material limit is not overcome, pagoda's historical and regional problems have not been analyzed, and pagoda construction is centered on pagoda construction. Therefore, this study examined the local cultural characteristics on the construction of brick pagodas. As a result, cultural exchange between Korea and China was performed through the silk road and there was a marine route for cultural exchange. Such exchange was shared with the East Asia area as well, which can be found by comparing remains at related areas. Exchange with China can be mentioned as the selective exchange of local powers as well as blind learning. Second, brick pagoda were constructed in Korea because of the good quality soil easily. Uisang's Hwaeomjong was negotiated with the main power not agreeing with Buddhism, which was popularized and the local power. Third, brick pagoda construction was influenced by negotiation related between Balhae and Silla, in which the ethnic influence was locally affected and could be mentioned as being a culturally selective result transferred from China. As a result, brick pagodas can be oriented by forming a unitary state rather than a small country within China's influence range as well as cultural transfer through the silk road.

• Journal of Broadcast Engineering
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• v.10 no.2
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• pp.210-220
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• 2005

This paper presents and analyzes laboratory test results of Equalization Digital On-Channel Repeater (EDOCR) using ATSC(Advanced Television Systems Committee) terrestrial digital TV broadcasting system. The EDOCR laboratory test, which is done at CRC(Communications Research Centre) Canada, is classified to receiver test, transmitter test, and synchronization test between transmission and reception frequencies. The receiver part includes feedback signal, random noise, single echo, multi-path ensemble, and NTSC/DTV interference test. The transmitter part includes out-of channel emission, quality of transmitting signal, and phase noise test. By the field test results, the receiver part of the EDOCR eliminates average 5.5 dB of feedback or single echo signal in range of 0 to 11 ${\mu}s$ and has average 18.6 dB at TOV(Threshold of Visibility) under random noise environment. Also, the transmitter part of the EDOCR satisfies the specification of US FCC(Federal Communications Commission), and frequency difference between transmitter and receiver is zero.

• Applied Chemistry for Engineering
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• v.24 no.6
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• pp.656-662
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• 2013

The iron oxide ($Fe_3O_4$) particles in the coolant of the secondary system of a nuclear power plant reduce the heat transfer performance or induce corrosion on the surface of the heat transfer tube. To prevent these problems, we conducted a study to improve the dispersion stability of iron oxide using polymeric dispersant injection in simulated secondary system water. The three kinds of anionic polymers containing carboxyl groups were selected. The dispersion characteristics of the iron oxide particles with the polymeric dispersants were evaluated by performing a settling test and measuring the transmission, the zeta potential, and the hydrodynamic particle size of the colloid solutions. Polymeric dispersants had a significant impact on the iron oxide dispersion stability in an aqueous solution. While the dispersant injection tended to improve the dispersion stability, the dispersion stability of iron oxide did not increase linearly with an increase in the dispersant concentration. This non-linearity is due to the agglomerations between the iron oxide particles above a critical dispersant concentration. The effect of the dispersant on the dispersion stability improvement was significant when the dispersant concentration ratio (ppm, dispersant/magnetite) was in the range of 0.1 to 0.01. This suggests that the optimization of dispersant concentration is required to maximize the iron oxide removal effect with the dispersant injection considering the applied environments, the iron oxide concentration and the concentration ratio of dispersant to iron oxide.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.2A
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• pp.114-126
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• 2011

Video streaming over wireless multi-hop networks(WMNs) contains the following challenges from channel fading and variable bandwidth of wireless channel, and it cause degradation of video streaming performance. To overcome the challenges, currently, WMNs can use Forward Error Correction (FEC) mechanism. In WMNs, traditional FEC schemes, E2E-FEC and HbH-FEC, for video streaming are applied, but it has long transmission delay, high computational complexity and inefficient usage of resource. Also, to distinguish network status in streaming path, it has limitation. In this paper, we propose monitoring-based coordination of network-adaptive hop-to-end(H2E) FEC scheme. To enable proposed scheme, we apply a centralized coordinator. The coordinator has observing overall monitoring information and coordinating H2E-FEC mechanism. Main points of H2E-FEC is distinguishing operation range as well as selecting FEC starting node and redundancy from monitored results in coordination. To verify the proposed scheme, we perform extensive experiment over the OMF(Orbit Measurement Framework) and IEEE 802.1la-based multi-hop WMN testbed, and we carry out performance improvement, 17%, from performance comparison by existing FEC scheme.

• Journal of the Korean Magnetics Society
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• v.20 no.1
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• pp.18-23
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• 2010

Ferromagnetic resonance (FMR) measurement is an important experimental technique for the study of magnetic dynamics. We designed and set up the vector network analyzer ferromagnetic resonance (VNA-FMR) measurement system with home made coplanar waveguides (CPW). We examined 10-, 20-, 40-nm thick Py thin films to test the performance of the VNA-FMR measurement system. We measured S-parameter (transmission/reflection coefficient) of Py thin films on a CPW. Resonance frequency is investigated from 2.5 to 7 GHz for a field range from 0 to 490 Oe. The VNA-FMR data shows the resonance frequency increment when the external magnetic field increases. We also investigated Gilbert damping constant of Py thin film using resonance frequency (${\omega}_r$) and linewidth ($\Delta\omega$). After investigating dependence of thickness, we find that an decrease in S-parameter intensity as Py thin film thickness decreases. And the FMR results show that the effective saturation magnetization, $M_{eff}$, increase from 7.205($\pm$0.013) kOe to 7.840($\pm$0.014) kOe, while the film thickness varies from 10 to 40 nm.

• Mycobiology
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• v.45 no.3
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• pp.160-171
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• 2017

Larvae of Bradysia agrestis, an insect vector that transports plant pathogens, were sampled from geographically isolated regions in Korea to identify their cutaneous fungal and bacterial flora. Sampled areas were chosen within the distribution range of B. agrestis; each site was more than 91 km apart to ensure geographical segregation. We isolated 76 microbial (fungi and bacteria) strains (site 1, 29; site 2, 29; site 3, 18 strains) that were identified on the basis of morphological differences. Species identification was molecularly confirmed by determination of universal fungal internal transcribed spacer and bacterial 16S rRNA gene sequences in comparison to sequences in the EzTaxon database and the NCBI GenBank database, and their phylogenetic relationships were determined. The fungal isolates belonged to 2 phyla, 5 classes, and 7 genera; bacterial species belonged to 23 genera and 32 species. Microbial diversity differed significantly among the geographical groups with respect to Margalef's richness (3.9, 3.6, and 4.5), Menhinick's index (2.65, 2.46, and 3.30), Simpson's index (0.06, 0.12, and 0.01), and Shannon's index (2.50, 2.17, and 2.58). Although the microbial genera distribution or diversity values clearly varied among geographical groups, common genera were identified in all groups, including the fungal genus Cladosporium, and the bacterial genera Bacillus and Rhodococcus. According to classic principles of co-evolutionary relationship, these genera might have a closer association with their host insect vector B. agrestis than other genera identified. Some cutaneous bacterial genera (e.g., Pseudomonas) displaying weak interdependency with insect vectors may be hazardous to agricultural environments via mechanical transmission via B. agrestis. This study provides comprehensive information regarding the cutaneous microflora of B. agrestis, which can help in the control of such pests for crop management.

• Journal of the Korean Solar Energy Society
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• v.34 no.5
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• pp.89-99
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• 2014

The determination of the solar and thermal performance of fenestration is required for the evaluation of fenestration energy performance, estimating building load. Presently, there exist several methods for determining the thermal transmission(U-value) and solar heat gain coefficient (SHGC) of fenestration system. These method are commonly grouped under calculation or experimental methods. While U-value testing and calculation methods have been long established, SHGC has been evaluated only by the method of calculation under the lack of any established testing method. However, it is difficult to assess the exact SHGC for various types of fenestration with sun-shading or other solar control systems. The purpose of this study was to evaluate the effect of interior venetian blind and roll screen on the SHGC of glazing system. SHGC has been evaluated by the KS L 9107 test method and exiting calculation method for precise comparison of the energy performances of various shading devices. In this research, the test sample consists of three different types of double glazing unit with venetian blind and roll screen. Slat angles of venetian blind were changed to $-45^{\circ}$, $0^{\circ}$, and$-45^{\circ}$. For the roll screen, measurements were taken with the roll screen in the closed position. In result, the venetian blind reduced SHGC by 21.2~28.4% at $45^{\circ}$, when compared to the double glazing unit. The roll screen reduced SHGC by 34.4~41.7% at closed. The differences between the measured and calculated SHGC were found to range between 0.001(0.2%) and 0.047(11.1%) for all test cases. For the cases of venetian blind $-45^{\circ}$, $0^{\circ}$ and $45^{\circ}$, the deviation ratio were 3.6~9.8%, 1.1~2.6%, 4.2~11.1%, respectively. For the case of roll screen, the deviation ratio were 4.1~5.7%.

• Journal of Korea Water Resources Association
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• v.50 no.12
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• pp.803-813
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• 2017

Recently, various studies have been conducted to optimize the pump operation scheduling and/or the pump/tank size minimizing the system cost of water distribution network. Prior to that, it is important to understand the sensitivity of pump/tank size on the system cost and overall water quality. Here, we have performed the sensitivity analysis to investigate the effect of pump/tank size on the economic cost (construction and operation) and water quality (water age). The analysis was applied on a real, large-scale water transmission network currently operating in South Korea. The results revealed that the pump/tank size has a strong influence on system construction/operation costs. Especially, the tank size has a significant effect on the system-wide water quality. In the case of applied networks, the operating cost decreases as the capacity of the facility increases, but the design cost increases. Using a sensitivity analysis, a suitable range of pump/tank size could be suggested to minimize costs and stabilize the water quality at the same time prior to a system design.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.3
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• pp.361-366
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• 1997

To determine the physiological, biochemical characteristics and toxicity of hemolysin produced by a novel sucrose positive Vibrio (Vibrio sp. D5) isolated from estuary of Kum river, it was compared with already known sucrose positive Vibrio. Salinity, pH, temperature and conductivity of place where Vibrio sp. D5 was isolated were $4.7\%_{\circ},\;7.6,\;24^{\circ}C$ and $7800{\mu}MHOS$, respectively. Physiological and biochemical characteristics distingiushed Vibrio sp. D5 from other sucrose positive Vibrio: V. alginoipicus, V. cholerae, V. cincinnatiensis, V. fluvialis, V. furnissii and V. metschnikovii. The range of salinity and pH for growth of Vibrio sp. D5 were $0.5\%\~7.5\%$ and $4.5\~9.5$, respectively. Vibrio sp. D5 exhibited typical yellow colony on TCBS agar plate and curved rod type upon transmission electron microscopy (TEM). Vibrio sp. D5 had lethal toxicity against mouse in case of intraperitoneal injection with its culture and showed hemolysin activity on human blood agar and sheep blood agar. Ubrio sp. D5 also demonstrated vascular permeability activity toward rat. From the above results, Vibrio sp. D5 was ascertained to be a novel pathogenic Vibrio.

• Korean Journal of Agricultural Science
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• v.14 no.1
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• pp.16-25
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• 1987

Colletotrichum acutatum, C. coccodes, C. dematium and C. gloeosporioides were detected in seed samples of red pepper (Capsicum annuum). C. dematium and C. gloeosporioides were the predominant species, maximum seed infection of the species in some samples were 84% and 28%, respectively. C. acutatum and C. coccodes were recorded only in low percentages of 1-2. The blotter method proved more suitable for detecting Colletotricum spp. than the deep freezing blotter or agar plate methods. Plating of seed components showed that C. dematium and C. gloeosporioides were recovered more frequently from seed coat, and decreasing amounts of infection were observed in the endosperm and cotyledon. Seed-borne C. dematium and C. gloeosporioides caused seed rot, damping-off, seedling blight and brown discoloration of cotyledon and hypocotyl when infected seeds were sown in agar of test tube or in soil. Inoculation experiments showed that C. acutatum was pathogenic to red fruit of red pepper and C. coccodes was highly pathogenic to red fruit and weakly pathogenic to leaf of the plant. C. dematium was highly pathogenic to leaf and green fruit and C. gloeosporioides was pathogenic to not only leaf but also green and red fruits. Host range of the four seed-borne species of Colletotrichum was also investigated.