• Journal of fish pathology
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• v.13 no.2
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• pp.121-127
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• 2000

From August to October 1998, over 60% mortality of cultured striped beakperch Oplegnathus fasciatus was occurred in net cages along the southern coast of Korea. Moribund fish showed some clinical signs of lethargic behavior, dark coloration or decoloration, severe gill anemia and enlargement of spleen. Also enlarged basophilic cells showing Feulgen -positive reaction were observed in the tissue section of spleen, kidney, liver and heart of the diseased fish. GF cells inoculated with spleen homogenate of diseased fish produced cytopathic effect of enlarged and rounded cells, therefore the causative virus was isolated from diseased fish. Striped beakperch fingerlings intraperitoneally inoculated with the causative virus ($10^4TCID_{50}$/0.1 ml) revealed symptoms similar to those of naturally infected fish and died from 7 to 14 days post injection. Transmission electron microscopy revealed that the causative virus was enveloped icosahedral particle with 120~130 nm in diameter. PCR products of the expected size (500 bp) were amplified with a primer set based on the ATPase gene of RSIV(red sea bream iridovirus) using template DNAs which were extracted from the spleen of diseased fish and GF cells inoculated with the causative virus. According to the analysis of nucleotide sequence of these PCR products, the sequence from ATPase cDNA gene of the causative virus showed 95% homology with that of RSIV. These results indicate that the mass mortality in the cultured striped beakperch was caused by the infection of iridovirus similar to RSIV.

• Korean Journal of Environmental Biology
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• v.35 no.4
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• pp.476-491
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• 2017

The water spider (Argyroneta aquatica), a rare member of its species, is one of the few insects known to live under water all over the world. In Korea, the water spider can be found only in the Eundae-ri, Yeoncheon, Gyeonggi province, where they are designated as a natural monument. However, loss of habitat is obvious, as the Eundae-ri wetland undergoes hydrarch succession. Loss of habitat has a direct impact on the water spider population. Thus protective measures for the water spider are needed to preserve the water spider habitat. In this study, a sweeping and visual survey of insect species was conducted in the water spider habitat from May to September 2015. The characteristics of each one of the different insect species and the community features were analyzed in this study. A total of 3,929 insects representing 276 species from 13 orders collected for the analysis. The most frequently collected insects from the Order Hemiptera represented 24.2% of total species and 82.3% of the total number of insects. Community analyses showed dominance, diversity, evenness, and richness indices of 0.23, 2.27, 0.41, and 31.2, respectively. Compared with the previous survey data, these results showed that reduction of the spider's wetland habitat caused the most commonly collected insects to adapt and spread to the surrounding terrestrial environment.

• Korean Journal of Food Science and Technology
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• v.12 no.2
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• pp.109-114
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• 1980

Protein efficiency ratio (PER), net protein utilization (NPU), nitrogen digestibility (ND), organ weights, and amino acid composition were investigated for rapeseed protein isolates (RPI) prepared by alkaline countercurrent extraction and isoelectric precipitation of defatted rapeseed meal (DRM). The PER values for 3 kinds of RPI obtained at pI of 6.7, 5.6 and 5.0 were 2.8, 3.1 and 2.9, and for DRM 2.5 while the NPU values for these RPI appeared to be 68, 73 and 71 %, and for DRM 56 %, respectively. Mean ND (85%), food intake (87), and weight gain (37.6) for RPI were significantly different from those of DRM (71 %, 77, and 28, respectively). There was no signicant difference in the PER among three RPI and casein (3.0), nor in the NPU among those proteins and casein (74%). These data attributed to the favorable amino acid patterns of proteins isolated which contained balanced essential amino acids in proportions which meet the requirements of human adult(FAO/WHO, 1973).

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.10
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• pp.520-526
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• 2016

This study aims to develop a distress prediction model, in order to evaluate the distress prediction power for first-class hotels and to calculate the average financial ratio in the Seoul area by using the financial ratios of hotels in 2015. The sample data was collected from 19 first-class hotels in Seoul and the financial ratios extracted from 14 of these 19 hotels. The results show firstly that the seven financial ratios, viz. the current ratio, total borrowings and bonds payable to total assets, interest coverage ratio to operating income, operating income to sales, net income to stockholders' equity, ratio of cash flows from operating activities to sales and total assets turnover, enable the top-level corporations to be discriminated from the failed corporations and, secondly, by using these seven financial ratios, a discriminant function which classifies the corporations into top-level and failed ones is estimated by linear multiple discriminant analysis. The accuracy of prediction of this discriminant capability turned out to be 87.9%. The accuracy of the estimates obtained by discriminant analysis indicates that the distress prediction model's distress prediction power is 78.95%. According to the analysis results, hotel management groups which administrate low level corporations need to focus on the classification of these seven financial ratios. Furthermore, hotel corporations have very different financial structures and failure prediction indicators from other industries. In accordance with this finding, for the development of credit evaluation systems for such hotel corporations, there is a need for systems to be developed that reflect hotel corporations' financial features.

• Current Research on Agriculture and Life Sciences
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• v.4
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• pp.70-76
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• 1986

The purpose of this study is to offer the basic data of the tidal river development program by grasping the diffusion between the high density-sea water and the low density-fresh water in the tidal river. The tidal range of Hyungsan river which flows at Youngil bay in Pohang was selected to analysis the phenomenon of density current. The results obtained are as follows ; The tide of Youngil bay was one time a day, 0.104m in high tide difference and 0.085m in mean tidy difference. The change of sea level by tide was negligible. The volume of reserved water by sea water was $2,700,000m^3$ and available water of irrigation was $1,200,000m^3$ that salt density is below $750{\mu}{\mho}/cm$ out of total volume. Salt intrusion phenomenon by density current was a little water level change, however, it become a salt wedge type by the much salt invasion during the spring tide and it makes a well-mixed type by the retreating salt wedge during the neap tide. As long as there were some density differences between sea water and fresh water, net upstream flow was existed along the bottom of water way from the estuary to the upstream channel.

• Journal of the Korean Geotechnical Society
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• v.33 no.11
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• pp.73-82
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• 2017

Recently, offshore bucket cut-off walls were developed to solve several problems in conventional offshore cut-off walls. In this study, a numerical analysis was carried out to investigate the seepage stability of offshore bucket cut-off walls. The ground was assumed as uniform homogeneous sand and steady state flow conditions were applied. The flow condition was compared among 2-dimensional flow (2-D), 2-dimensional concentrated flow (2-DC), and axisymmetric flow. The analysis results showed that the seepage velocities in axisymmetric flow were about 1.5 and 2 times larger than those of 2-DC and 2-D flow conditions, respectively. Thereafter, the axisymmetric flow condition was applied because the seepage flow was concentrated toward the center of the circular-shaped wall. A parametric study was performed varying bucket radius, penetration depth, total head difference between in and outside of the wall. The exit gradient, which used for the calculation of piping stability, decreased with increase of the penetration depth and bucket radius. Design charts were proposed to estimate the factor of safety and the exit gradient at various analysis conditions. Finally, the design equation was proposed to calculate the exit gradient for the preliminary design of the bucket cut-off wall.

• Review of Culture and Economy
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• v.17 no.2
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• pp.63-80
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• 2014

This study evaluates the importance of negotiation agendas and the possibility of reaching the Korea-China FTA agreement. It assesses the current situation of trade barriers in the audiovisual service sector of China and then examines a survey of practitioners and experts to screen important regulations. The results are as follows: First, considering the national economic situation in Korea and the environment of the Chinese trade barrier, an important agenda is to enable the direct service of online games and to reach a co-production agreement in the audiovisual service sector. Second, an agenda regarding the co-production agreement of an audio-visual service sector has high potential to be realized, followed by agendas regarding online game and music services. In the broadcasting and film service sectors, with their high cultural identity, a mutual cooperative approach is needed. Korea bringing up the agenda regarding online service may allow it to gain a net benefit for the next FATs. To realize a mutual cooperative approach, it is necessary to form a frame of mutual interests and cooperation through a co-production agreement of audio-visual service. If both countries agree to acknowledge co-produced content as each country's contents, both would benefit.

• Journal of Convergence for Information Technology
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• v.9 no.12
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• pp.141-146
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• 2019

Economic analysis predicts that the drone market will grow, and the growth of the toy and hobby drone market is expected to gradually expand. Drone expectations are rising due to the net economic function of drone market growth, but accidents due to improper management and operations are also increasing. The difference in toy drone performance is incomparably small compared to industrial drone performance, but the ordinary buyer can not know whether the difference can cause an accident during use. The toy drones used in this study were obtained from KC and CE certification, and 20 kinds of drones were used. The flight time ranged from a minimum of 3 minutes to a maximum of 12 minutes, and the control distance ranged from a minimum of 20m to a maximum of 380m. Therefore, it is necessary to secure product safety through sampling inspection of the radio wave output of toy drones, and it is also necessary to mount an algorithm that automatically lowers the altitude or hover when exceeding the limit flight distance. For future research, we will build data to establish toy drone safety standards through a altitude testing and impact testing of toy drone.

• Korea journal of population studies
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• v.9 no.2
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• pp.67-78
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• 1986

With Economic Development Plan, the Korean National Family Plan Program was introduced in early 1960's. The program, which has been a way for constraining population increase, has obtained excellent results. In other word, it has had an important role in controlling the increase in population. The purpose of this study is to analyze the change of fertility rates since 1970 and the lever of completed fertility of Korean women since 1960. There are Age-specific Fertility Rate(ASFR), Total Fertility Rate(TFR), Gross Reproduction Rate(GRR) and Net Reproduction Rate(NRR) etc. in indices of period fertility. It is also possible to be seen the completed fertility rates by using Parity Progression Ratio. The data necessary for this study were obtained from Population & Housing Census Report from the year of 1960 to 1980 and Vital Statistics from 1980 to 1984, which conducted by Economic Planning Board, Republic of Korea. The summarized results of this study were as follows : 1. Age-specific Fertility Fertility Rate(ASFR) has been continuously decreasing till now. The ASFR for the women aged 25 to 29 was higher than those of any other groups and the ASFR for the women aged 20 to 24 was higher than that of the women aged 30 to 34 since the mid 1970's. 2. There are Total Fertility Rate(TFR), Gross Reproduction Rate(GRR) and Ney Reproduction Rate(NRR) etc. in reproduction rates. First of all, TFR and GRR have been declining except late of 1970's and TFR showed 2.23 per ever-married women, GRR was 1.05 in 1982. Next, the change of NRR could not be found without life table by year and only NRR for the time of census was to be found. In 1980, NRR showed 1.27 per ever-married women and the level was still out of reach at replacement level of population. 3. Specific Fertility Rate by Birth Order(SFRBO) showed to be declined continually since 1972. Especially the SFRBO of the third live birth was decreased from about 22 per 1,000 ever-married women in 1972 to 12 or so in 1982. 4. To know the level of completed fertility, the mean number of completed live births per ever-married women was calculated from 1960 to 1980. The number of completed live births was more than 5 per ever-married women by the year of 1975 but have been declining and resulted in 4.69 in 1980.

• Nuclear Engineering and Technology
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• v.53 no.10
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• pp.3217-3228
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• 2021

Flow blockage of the fuel assembly in the lead-based fast reactor (LFR) may produce critical local spots, which will result in cladding failure and threaten reactor safety. In this study, the flow blockage characteristics were analyzed with the sub-channel analysis method, and the circumferentially-varied method was employed for considering the non-uniform distribution of circumferential temperature. The developed sub-channel analysis code SACOS-PB was validated by a heat transfer experiment in a blocked 19-rod bundle cooled by lead-bismuth eutectic. The deviations between the predicted coolant temperature and experimental values are within ±5%, including small and large flow blockage scenarios. And the temperature distributions of the fuel rod could be better simulated by the circumferentially-varied method for the small blockage scenario. Based on the validated code, the analysis of blockage characteristics was conducted. It could be seen from the temperature and flow distributions that a large blockage accident is more destructive compared with a small one. The sensitivity analysis shows that the closer the blockage location is to the exit, the more dangerous the accident is. Similarly, a larger blockage length will lead to a more serious case. And a higher exit temperature will be generated resulting from a higher peak coolant temperature of the blocked region. This work could provide a reference for the future design and development of the LFR.