• Geophysics and Geophysical Exploration
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• v.11 no.1
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• pp.68-77
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• 2008

We have developed an inversion algorithm for loop-loop electromagnetic (EM) data, based on the localised non-linear or extended Born approximation to the solution of the 2.5D integral equation describing an EM scattering problem. Source and receiver configuration may be horizontal co-planar (HCP) or vertical co-planar (VCP). Both multi-frequency and multi-separation data can be incorporated. Our inversion code runs on a PC platform without heavy computational load. For the sake of stable and high-resolution performance of the inversion, we implemented an algorithm determining an optimum spatially varying Lagrangian multiplier as a function of sensitivity distribution, through parameter resolution matrix and Backus-Gilbert spread function analysis. Considering that the different source-receiver orientation characteristics cause inconsistent sensitivities to the resistivity structure in simultaneous inversion of HCP and VCP data, which affects the stability and resolution of the inversion result, we adapted a weighting scheme based on the variances of misfits between the measured and calculated datasets. The accuracy of the modelling code that we have developed has been proven over the frequency, conductivity, and geometric ranges typically used in a loop-loop EM system through comparison with 2.5D finite-element modelling results. We first applied the inversion to synthetic data, from a model with resistive as well as conductive inhomogeneities embedded in a homogeneous half-space, to validate its performance. Applying the inversion to field data and comparing the result with that of dc resistivity data, we conclude that the newly developed algorithm provides a reasonable image of the subsurface.

• Korean Journal of Poultry Science
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• v.41 no.4
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• pp.305-311
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• 2014

Copy number variation (CNV) is a form of structural variation that shows various numbers of copies in segments of the DNA. It has been shown to account for phenotypic variations in human diseases and agricultural production traits. Currently, most of chicken breeds in the poultry industry are based on European-origin breeds that have been mostly provided from several international breeding companies. Therefore, National Institute of Animal Science, RDA has been trying to restore and improve Korean native chicken breeds (12 lines of 5 breeds) for about 20 years. Thanks to the recent advance of sequencing technologies, genome-wide CNV can be accessed in the higher resolution throughout the genome of species of interest. However, there is no systematic study available to dissect the CNV in the native chicken breed in Korea. Here, we report genome-wide copy number variations identified from a genome of Korean native chicken (Line L) by comparing between the chicken reference sequence assembly (Gallus gallus) and a de novo sequencing assembly of the Korean native chicken (Line L). Throughout all twenty eight chicken autosomes, we identified a total of 501 CNVs; defined as gain and loss of duplication and deletion respectively. Furthermore, we performed gene ontology (GO) analysis for the putative CNVs using DAVID, leading to 68 GO terms clustered independently. Of the clustered GO terms, genes related to transcription and gene regulation were mainly detected. This study provides useful genomic resource to investigate potential biological implications of CNVs with traits of interest in the Korean native chicken.

• Journal of the Korean Society of Radiology
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• v.11 no.7
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• pp.571-578
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• 2017

Bubbles are generated by the boiling of the cooling water when an accident occurs in the reactor and then in order to measure the void fraction, the Optical Fiber Probe(OFP) and optical camera are used in thermal hydraulic safety research. However, such an optical method is not suitable for measuring the void fraction in a $17{\times}17$ array of fuel rods due to the geometrical limitations. This study was conducted as a preliminary study using x-ray system and various phantoms before applying to rod bundles. Through radiographic and tomographic experiments, the tube voltage of the x-ray generator was 130 kVp and the tube current was 1 mA. In addition, it is possible to measure the hole of 1mm in size visually through the bubble resolution phantom, and it is confirmed that the contrast is relatively decreased in the inside of the freon in the case of the contrast evaluation using the road phantom. However, we could obtain good image without distortion when reconstructing the image. Bubble generation phantom experiments were used to confirm the flow direction of the bubbles and to acquire tomography images. The image J tool was used to measure the void fraction of 18 % for a single tomography image. This study has carried out previous researches for the measurement of the bubble rate around the nuclear fuel and could be used as a basic research for continuous research.

• Korean Journal of Ichthyology
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• v.27 no.3
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• pp.189-198
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• 2015

This research has been launched in order to observe the osteological development of sevenband grouper, Epinephelus septemfasciatus larvae and juveniles and will be used for the basic data of phylogenetically systematics research. We got some samples of larvae and juveniles from a adult fish which belongs to the sea cage in Geomun-do, Yeosu-si, Jeolla-namdo province, and we have watched them. The average of breeding water temperature was $21.5{\sim}24.5^{\circ}C$ (average $23.0{\pm}1.5^{\circ}C$). In yolk-sac larvae just after hatching, ossification was not observed at all, and when the average total length reached 2.66 mm, the premaxillary and maxillary forming the upper jaw, dentary forming the lower jaw, and parasphenoid forming the skull base were ossified. In addition, the preopercle and opercle forming the opercular region began to be ossified. The caudal skeleton supporting the caudal fin is built with the caudal complex consisting of the malleus and incus. Until the average total length reached 2.59 mm, ossification did not occur at all and the urostyle bent at 45-degree angle. As to the ossification of the pterygiophore, when the average total length was 6.12 mm, the first interhemal spine began to be ossified in articulation with two spines of the anal fin, and the synapse also began to be ossified in articulation with two spines of the dorsal fin. When the average total length was 21.9 mm, individuals with completed ossification of the interhemal spines and synaptic clefts began to appear.

• Journal of Advanced Marine Engineering and Technology
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• v.41 no.4
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• pp.323-329
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• 2017

Nowadays, considering global warming and enhanced prohibition to discharge pollutants at sea, all of existing operation-ships must lead to the reduction of fuel consumption. International standards of International Maritime Organization and EU rules governing harbor pollutants are being strengthened. Therefore, ship-owners and operators are seeking ways to reduce $CO_2$, SOx, and NOx emissions. Although world trade continues to expand, total fuel usage for sea transport tends to diminish. However, ICS(International Chamber of Shipping) has set a goal of reducing $CO_2$ emissions from shipping by 50% until 2050. In addition, with respect to the Paris Climate Change Accord in 2015, IMO proposes to set up a reduction target of GHG emission from existing operation-ships. For setting up a reduction target of GHG from international maritime transport, "A data collection system for fuel consumption" will be introduced in the near future. In order to effectively reduce the use of fuel in a ship in accordance with the trend of compulsory fuel saving from operation ships, this paper suggested adoption of an Incentive-Penalty scheme based on Emission-Trading-Scheme, Carbon Tax, and basic calculation formula after verifying the EEOI level for a year.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2002.11a
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• pp.147-153
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• 2002

Due to the growth of population and industrial development at the coastal cities, there has been much increase in necessity to effective control of the wastes into the coastal water and river. The amount of disposal at those waters has been increased rapidly and it is necessary for us to track of it in order to keep the water clean. The investigation and research related to the water quality in this region have been conducted continuously but the systematic survey of the disposed wastes at the bottom was neglected and/or minor. In this study we surveyed the status of disposed waste distribution at the bottom coastal water and river from the scanned images. The intensity of sound received by the side scan sonar tow vehicle from the sea floor provides information as to the general distribution and characteristics of the superficial wastes. The port and starboard side scanned images produced from a transducer borne on a tow fish connected by tow cable to a tug boat have the area with width of 22m∼112m, and band of 44m∼224m. All data are displayed in real-time on a high-resolution color display (1280 ${\times}$ 1024 pixels) together with position information by DGPS. From the field measurement and analysis of the recorded images, we could draw the location and distribution of bottom disposals. Furthermore, we made a database system which might be fundamental for planning the waste reception and process control system.

• Journal of Navigation and Port Research
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• v.39 no.1
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• pp.29-35
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• 2015

As the numbers of users of domestic passenger ships increased up to 14.5 millions at 2012, the numbers of ships accidents also increased as 2 times than ever. It will be very important to develop technologies related with safety design for onboard passengers and disclose the potential problems. This study performed consciousness survey on ordinary peoples' way finding who have not got any regular anti-disaster training, to develop evacuation models for evacuation feasibility studies. Followings are the results answered by 83 participants for 33 way finding questions. Respondents selected right ways more than 6~18% for 2 ways like T type, U type, Y type passages. But when there are some walkers and/or runners, respondents preferred to select the way where walkers or runners are. And more over the ratio of the ways that runners are on is comparatively higher than walkers. On 'ㅏ'type, 'ㅓ'type and 3 way type passages, even though the walkers and/or runners are affected to answerers, straight way were most preferred. And it is clear that peoples like bright passages. On the other hands, peoples responded as they like right, downward and near stairs more than left, upward and far stairs, respectively. and very few selected escalator and elevator for as evacuation stairs.

• Korean Journal of Construction Engineering and Management
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• v.11 no.3
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• pp.125-133
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• 2010

Although work-efficiency of construction machinery is a critical factor for estimating its workable-quantity perunit time, the efficiency figure table presented in the Poom-Sam that is used for Construction Cost Estimation of public sectors in Korea is very subjective for practical usage. In order to suggest objective work-efficiency table for a Pump-Dredger, domestic and overseas documentary records were investigated and on-going construction sites were also visited. Moreover, actual work quantities collected from the site visits were compared with the ones calculated based on the Standard Measurement Methods used in Japan. The research found that the table can be revised by means of detailing down by several factors, namely project type, depth of soil, undersea-site shape, and condition on the sea for better estimation of its workable-quantity. The research will be the foundation for applying the rapid development of Construction Equipment and technology to the appropriate cost estimations and the ground work of related studies.

• Proceedings of the Korean Society for Rock Mechanics Conference
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• 2008.03a
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• pp.79-88
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• 2008

Since the hydraulic fracturing field testing method was introduced first to Korean geotechnical engineers in 1994, there have been lots of progresses in a hardware system as well as an interpretation tool. The hydrofracturing system of first generation was the pipe-line type, so it was not easy to handle. It had been modified to a wire-line system at their second generation. It was more compact one but it also needed an additional air-compressor. Our current system is much more compact and operated by all-in-one system, so it doesn't need an additional air-compressor. With a progress in a hardware system, the software for analyzing the in-situ stress regime has also been progressed. For example, the shut-in pressure, which is the most ambiguous parameter to be obtained from hydrofracturing pressure curves, can now be acquired automatically from the various methods. While the hardware and software for hydrofracturing tests are being developed during the last decade, the author could accumulate the field test results which can cover the almost whole area of South Korea. Currently these field data are used widely in a feasibility study or a preliminary design step for tunnel construction in Korea. Regarding the difficulties in a site selection and a test performance for the in-situ stress measurement at an off-shore area, the in-situ stress regime obtained from the field experiences in the land area can be used indirectly for the design of a sub-sea tunnel. From the hydrofracturing stress measurements, the trend of magnitude and direction of in-situ stress field was shown identically with the geological information in Korea.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.36 no.4
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• pp.281-286
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• 2000

To analyze the shape of the net mouth of bottom trawl which is composed with 6 seams net, the field experiment was carried out on the sea near Kokunsan Is, Western sea of Korea. The distance of otter board, net height, trawl speed and resistance of the fishing gear were respectively measured according to the change of warp length and towing speed. The results obtained are summarized as follows : 1. The spreading distance of the otter board has been increased straightly according to the increment of towing speed and warp length. The rate of increase by the warp length has been greatly higher than the rate of increase by the towing speed. The total variation of the spreading distance was 57.0-82.8m, and it was occupied 43-62% of the hand rope, net pendent and the length of nets. 2. The height of net mouth has been decreased straightly according to the increment of towing speed and warp length. The rate of decrease by the towing speed has been greatly higher than the decrease rate of the warp length. The total variation of the net height was 3.1-4.0m. 3. When the distance of wing tip is increased, the height of net mouth is decreased, but the ratio of the decreasing rate of the height of net mouth for the increasing rate of the distance of wing tip was gradually low according to the increment of warp length. 4. The ratio of the distance of both wing tip for the height of net mouth has been increased gradually according to the increment of towing speed and warp length, and the total variation of the ratio was 4.17-7.81 times.