• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.3
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• pp.362-367
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• 2015

We followed the development of Pacific herring Clupea pallasii larvae after natural hatching in Korean coastal waters off Dadaepo, where the water temperature was $9^{\circ}C$. Twenty days after hatching, the larvae had (i) reached a total length (TL) of 10.8-12.2 mm, (ii) developed 9-11 dorsal fin rays, and (iii) branched melanophores along the dorsal line of the gut in the anterior half of the body and along the posterior half of the dorsal and ventral line. Thirty days after hatching, the larvae had reached 12.2-13.5 mm TL, and the number of dorsal fin rays had increased to 13-14. Thirty-five days days after hatching, the larvae had reached 14.0-14.7 mm TL, and the posterior ends of their notochords had begun to flex upward. Forty-five days days after hatching, the larvae had (i) reached 15.6-15.9 mm TL, (ii) a complete set of dorsal fin rays (15-16), (iii) 12-13 anal fin rays, and (iv) branched melanophores along the dorsal part of the lateral surfaces of the head behind the caudal terminus. Preflexion, flexion and postflexion stage larvae had TL values of 13.5 mm, 14.0-15.3 mm, and 15.6-15.9 mm, respectively.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.214-221
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• 2001

The Great Hall of Incheon International Airport Transportation Center has irregular curved roof structure. The structure consists of 13 main steel trusses. (the longest span of 162m, 480ton) The total weight of the truss is 6,300ton and the whole truss is made of 9,600 pieces which has the joint connected to maximum 13 different parts at one point and Roof Truss is supported by 12 Fabric Foundation. Considering the economical efficiency and the schedule, the Sliding Construction Method was used other than conventional erection method. The roof truss structure was divided into two blocks, 3,550ton and 2,700ton, each block was pre-erected on the Giant Sleigh off the site and was pulled 181m by using Tandem Pulling Jack and Strand to be set in place.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.7
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• pp.907-911
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• 2017

Objective: Intramuscular fat is one of the meat quality traits that is considered in the selection strategies for Hanwoo (Korean cattle). Different methods are used to estimate the breeding value of selection candidates. In the present work we focused on accuracy of different genotype relationship matrices as described by forni and pedigree based relationship matrix. Methods: The data set included a total of 778 animals that were genotyped for BovineSNP50 BeadChip. Among these 778 animals, 72 animals were sires for 706 reference animals and were used as a validation dataset. Single trait animal model (best linear unbiased prediction and genomic best linear unbiased prediction) was used to estimate the breeding values from genomic and pedigree information. Results: The diagonal elements for the pedigree based coefficients were slightly higher for the genomic relationship matrices (GRM) based coefficients while off diagonal elements were considerably low for GRM based coefficients. The accuracy of breeding value for the pedigree based relationship matrix (A) was 13% while for GRM (GOF, G05, and Yang) it was 0.37, 0.45, and 0.38, respectively. Conclusion: Accuracy of GRM was 1.5 times higher than A in this study. Therefore, genomic information will be more beneficial than pedigree information in the Hanwoo breeding program.

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.1
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• pp.71-77
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• 2014

According to the increasement of demand for energy around globe, the concern degree of advanced countries for ocean energy including offshore wind power becomes excited. In domestic case, the government set up a goal that jumps up to the third ranked powerful nation of offshore wind in the world until 2020 and announced "The plan for 2.5-gigawatt wind farm off the south-west coast by 2019". Also the legal basis was created in order to support development of offshore wind power as 'A law on development, use, supply and promotion for New energy and renewable energy' was established by law. However to promote offshore wind power projects, there are much difficulties that developers should be applied by permitting use of public water surface and regulations of several domestic public institution. Therefore in this paper, we suggested an alternative to promote efficient offshore wind power projects by comparative analysis between domestic and foreign on regulatory pathways for siting and permitting offshore wind facilities.

• Journal of the Korea Society of Computer and Information
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• v.13 no.1
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• pp.143-151
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• 2008

Execute IP traceback at this paper as target an intruder's attacking that Bypass Attack in order to avoid an exposure of own Real IP address Design IP traceback server and agent module, and install in Internet network system for Real IP traceback. Set up detection and chase range aggressive loop around connection arbitrariness, and attack in practice, and generate Real IP data cut off by fatal attacks after data and intrusion detection accessed general IP, and store to DB. Generate the Forensic data which Real IP confirms substance by Whois service, and ensured integrity and the reliability that buy to early legal proof data, and was devoted to of an invader Present the cyber criminal preventive effect that is dysfunction of Ubiquitous Information Society and an effective Real IP traceback system, and ensure a Forensic data generation basis regarding a judge's robe penalty through this paper study.

• Proceedings of the KIPE Conference
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• 2008.06a
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• pp.103-105
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• 2008

In grid-interconnection system, a fast, robust and precise phase angle detector is most important to grid synchronization and the active power control. The phase angle can be easily estimated by synchronous dq PLL system. On the other hand under unbalanced voltage condition, synchronous dq PLL system has problem that harmonics occur to phase angle or magnitude of grid voltage because of the effect of the negative sequence components. So, To eliminate the negative sequence components, the PLL method using APF (All Pass Filter) in a stationery reference frame to extract positive sequence components under unbalanced voltage condition is researched. In this paper, we propose a new PLL method with decoupling network using APF in a synchronous reference frame to extract the positive sequence components of the grid voltage under unbalanced grid. The cut-off frequency of APF in a synchronous reference frame can be set to twice of the fundamental frequency comparing with that of APF in a stationery reference frame which is the fundamental frequency. The proposed PLL strategy can detect the phase angle quickly and accurately under unbalanced gird voltages. Simulation and experimental results are presented to verify the proposed strategy under different kind of voltage dips.

• The Transactions of the Korean Institute of Power Electronics
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• v.23 no.2
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• pp.77-85
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• 2018

Renewable energy has been increasingly used and widely acclaimed as one of the solutions to rampant environmental problems. Among numerous kinds of renewable sources, the penetration rate of the PV system is relatively higher than that of others due to ease of installation. However, one disadvantage of the PV system is its dependence on weather condition. The PV system is especially critical when it is used for standalone systems because it cannot operate when the power generated from a PV module is not enough. Therefore, PV systems are often used with an energy storage system, such as batteries, to store backup energy when the weather condition is insufficient to supply power to the system. Blackout time can be reduced by increasing the size of the energy storage system, but it is a trade-off with system cost. In this work, optimal sizing of a standalone PV system is proposed to supply power to the system without blackout. The sizing of PV modules and batteries is performed by a simulation based on actual irradiation data collected during the past five years. The Life cycle costing of each system is evaluated to determine an optimal set of PV modules and batteries among several different combinations. The standalone PV system designed by the proposed method can supply power to the system with no interruption as long as the weather condition is similar to those of the past five years.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.6
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• pp.446-453
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• 2013

Clustering schemes have been adopted as an efficient solution to prolong network lifetime and improve network scalability. In such clustering schemes cluster ratio is represented by the rate of the number of cluster heads and the number of total nodes, and affects the performance of clustering schemes. In this paper, we mathematically analyze an optimal clustering ratio in wireless sensor networks. We consider a multi-hop to one-hop transmission case and aim to provide the optimal cluster ratio to minimize the system hop-count and maximize packet reception ratio between nodes. We examine its performance through a set of simulations. The simulation results show that the proposed optimal cluster ratio effectively reduce transmission count and enhance energy efficiency in wireless sensor networks.

• Journal of Korean Society for Atmospheric Environment
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• v.17 no.E3
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• pp.91-99
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• 2001

Plasma reactor was used to generate a high potential difference between two surfaces of concentric pyrex tubes by electrical current. The annular gap of the reactor was calculated by trial and error from the breakdown voltage equation and set at 0.45 cm. The overall objective of this research was to know the effects of the frequency, humidity, and residence time on the formation of nitrogen oxides in a plasma reactor. The primary voltage varied from 50 to 90 volts and the frequency was varied in increments of 10 Hz from 60 to 650 Hz at the primary voltage of 90. The increase in the secondary voltage was not linear but exponential at high frequencies. At a maximum concentration of about 745 ppm, the frequency and secondary voltage was 600 Hz and 4,200 volts, respectively. All tests for the effects of humidity on NO$_{x}$ production were performed at the optimal setting of 90 colts and 600 Hz frequency. Since the NO$_{x}$ production was not an one dimensional phenomenon, competing reactions were assumed to occur in the discharge chamber. The sharp peak concentration of 1,810 ppm was observed at 38% of relative humidity, The enhanced production was choked off, and the production rate rapidly dropped to 3 ppm at above 40% of relative humidity. It is assumed that the corona attacks the most vulnerable molecules in the reaction chamber before attacking other more lightly bonded molecules, possibly at humidities above 38% and the optimized 90 volt setting. Thus, there was not enough energy left after attacking all water molecules to decompose an appreciable amount of $N_2$. If nitrogen breakdown does not occur, then oxides of nitrogen are not likely to be produced.ced.

• Journal of the Korean Graphic Arts Communication Society
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• v.24 no.2
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• pp.61-68
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• 2006

Rubber rollers in off-set printing process are one of the most important factor, transferring the ink and water to the plate. Each different roughness of roller surface and different rubber compounds could effect to ink transparency and printability. Three different rubber compounds (NBR, EPDM, PU) and each different roughness of roller surface would show us different result of ink transparency and density of actual printing result. There might be a differences from actual printing result not only the amount of transferred ink, but there is also some other point we should check it out. According to the result of this studies, we found that different rubber compounds and their surface roughness directly effect to the rate of ink transfer. It also shows that the amount of transferred ink is not even and stable amount what we expect to get optimum printability. To reach a targeted printability with rollers, firstly it is necessary to choose correct rubber compounds with certain purpose and the roughness of roller surface has to be as smooth as less than $5{\mu}m{\sim}7{\mu}m$.