• Proceedings of the Korean Society of Embryo Transfer Conference
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• 2003.10a
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• pp.29-48
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• 2003

It is remarkable that nuclear transfer using differentiated donor cells can produce physiologically normal cloned animals, but the process is inefficient and highly prone to epigenetic errors. Aberrant patterns of gene expression in clones contribute to the cumulative losses and abnormal phenotypes observed throughout development. Any long lasting effects from cloning, as revealed in some mouse studies, need to be comprehensively evaluated in cloned livestock. These issues raise animal welfare concerns that currently limit the acceptability and applicability of the technology. It is expected that improved reprogramming of the donor genome will increase cloning efficiencies realising a wide range of new agricultural and medical opportunities. Efficient cloning potentially enables rapid dissemination of elite genotypes from nucleus herds to commercial producers. Initial commercialisation will, however, focus on producing small numbers of high value animals for natural breeding especially clones of progeny-tested sires. The continual advances in animal genomics towards the identification of genes that influence livestock production traits and human health increase the ability to genetically modify animals to enhance agricultural efficiency and produce superior quality food and biomedical products for niche markets. The potential opportunities inanimal agriculture are more challenging than those in biomedicine as they require greater biological efficiency at reduced cost to be economically viable and because of the more difficult consumer acceptance issues. Nevertheless, cloning and transgenesis are being used together to increase the genetic merit of livestock; however, the integration of this technology into farming systems remains some distance in the future.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2023.05a
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• pp.152-153
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• 2023

AIS has been widely used for maritime traffic assessment for its convenience. However, AIS has problems with position missing due to radio interference and transmission distance limit. On the other hand, satellite radar determines the location of ships over a wide sea regardless of the problems. This study proposes a noble method of stepwise threshold determination to detect ships from Sentinel-1. The proposed method is up to 25 times faster than the existing moving window-based threshold determination method, and the detection accuracy is similar.

• Journal of the Korean Society of Safety
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• v.38 no.6
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• pp.9-15
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• 2023

Hydrogen is gaining attention as a sustainable and renewable energy source, potentially replacing fossil fuels. Its high diffusivity, wide flammable range, and low ignition energy make it prone to ignition even with minimal friction, potentially leading to fire and explosion risks. Workplaces manage ignition risks by classifying areas with explosive atmospheres. However, the effective installation of a blast wall can significantly limit the spread of hydrogen, thereby enhancing workplace safety. To optimize the wall installation of this barrier, we employed the response surface methodology (RSM), considering variables such as wall distance, height, and width. We performed 17 simulations using the Box-Behnken design, conducted using FLACS software. This process yielded two objective functions: explosion likelihood near the barrier and explosion overpressure affecting the blast wall. We successfully achieved the optimal solution using multi-objective optimization for these two functions. We validated the optimal solution through verification simulations to ensure reliability, maintaining a margin of error of 5%. We anticipated that this method would efficiently determine the most effective installation of a blast wall while enhancing workplace safety.

• Journal of the Earthquake Engineering Society of Korea
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• v.22 no.6
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• pp.323-332
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• 2018

Recent two moderate earthquakes (2016 $M_w=5.4$ Gyeongju and 2017 $M_w=5.5$ Pohang) in Korea provided the unique chance of developing a set of relations to estimate instrumental seismic intensity in Korea by augmenting the time-history data from MMI seismic intensity regions above V to the insufficient data previously accumulated from the MMI regions limited up to IV. The MMI intensity regions of V and VI was identified by delineating the epicentral distance from the reference intensity statistics in distance derived by using the integrated MMI data obtained by combining the intensity survey results of KMA (Korea Meteorological Administration) and 'DYFI (Did You Feel It)' MMIs of USGS. The time-histories of the seismic stations from the MMI intensity regions above V were then preprocessed by applying the previously developed site-correction filters to be converted to a site-equivalent condition in a manner consistent with the previous study. The average values of the ground-motion parameters for the three ground motion parameters of PGA, PGV and BSPGA (Bracketed Summation of PGA per second for 30 seconds) were calculated for the MMI=V and VI and used to generate the dataset of the average values of the ground-motion parameters for the individual MMIs from I to VI. Based on this dataset, the linear regression analysis resulted in the following relations with proposed valid ranges of MMI. $MMI=2.36{\times}log_{10}(PGA(gal))+1.44$ ($I{\leq}MMI$$MMI=2.44{\times}log_{10}(PGV(kine))+4.86$ ($I{\leq}MMI$$MMI=2.59{\times}log_{10}(BSPGA(gal{\cdot}sec))-1.02$ ($I{\leq}MMI$

• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.5
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• pp.809-822
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• 2018

A quantitative risk assessment has been introduced to quantitatively evaluate fire risk as a means of performance based fire protection design in the design of railway tunnel disaster prevention facilities. However, there are insufficient studies to examine the effect of various risk factors on the risk. Therefore, in this study, the risk assessment was conducted on the model tunnel in order to examine the effects of the evacuation start time delay and the fire growth curve on the quantitative risk assessment. As a result of the analysis of the scenario, the fatalities occurred mainly when escapes in the same direction as the direction of the fire smoke movement. In addition, after the FED exceeded 0.3, the maximum fatalities occurred within 10 minutes. In the range of relatively low risk, distance between cross passages, evacuation delay time and fire growth curve were found to affect the risk, but they were found to have little effect on the condition that the risk reached the limit. Especially, in this study, it was evaluated that the evacuation delay time reduction, fire intensity and duration reduction effect were not observed when the distance between cross passages was more than 1500 m.

• Journal of the Korea Safety Management & Science
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• v.13 no.4
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• pp.109-116
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• 2011

This study examined into property of flour dust explosion to get the basic data for safety of industry by protecting accident of dust explosion. The experiment was conducted to know the effect of distance between explodes in the experiment device, effect of flour dust concentration, effect of humidity, effect of explosion pressure to the dust concentration and effect of inactive substance additive. The study indicated that explosion was happened effectively at the optimum distance 100mm or less in inter-polar distance, and minimum ignition energy was measured at 6mm. The data of feed concentration to the probability of explosion showed that the smaller the particle diameter was, the larger probability of explosion was, and the higher the dust concentration was, the more increased the pressure of explosion was, but more than upper limit of dust concentration, then the explosion of pressure decreased. For the effect of humidity, the more it contained water, the more decreased the ignition energy of dust was, so increased minimum explosive concentration, and effective water content was minimum 10% or more. Inactive substance additive was effective in adding more than 15% CaCO3 and CaO as substance inhibiting dust explosion, in which CaCO3 was more effective than CaO. the analysis of the flame of dust explosion was performed by high-speed video camera, it showed the size of flame bacame smaller in order that sub feed, main feed, wheat powder. As a result, sub feed was expected to be less dangerous than others.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.1
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• pp.15-21
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• 2011

In the range-based localization, the localization accuracy will be high dependent on the accuracy of distance measurement between two nodes. The received signal strength(RSS) is one of the simplest methods of distance measurement, and can be easily implemented in a ranging-based method. However, a RSS-based localization scheme has few problems. One problem is that the signal in the communication channel is affected by many factors such as fading, shadowing, obstacle, and etc, which makes the error of distance measurement occur and the localization accuracy of sensor node be low. The other problem is that the sensor node estimates its location for itself in most cases of the RSS-based localization schemes, which makes the sensor network life time be reduced due to the battery limit of sensor nodes. Since beacon nodes usually have more resources than sensor nodes in terms of computation ability and battery, the beacon node based localization scheme can expand the life time of the sensor network. In this paper, therefore we propose a beacon node based localization algorithm using received signal strength(RSS) and path loss calibration in order to overcome the aforementioned problems. Through simulations, we prove the efficiency of the proposed scheme.

• The Journal of Engineering Geology
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• v.27 no.2
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• pp.153-164
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• 2017

The geological factors for causing ground subsidence are very diverse. It can be affected by any geological or extrinsic influences, and even within the same geological factor, the soil depression impact factor can be determined by different physical properties. As a result of reviewing a large number of papers and case histories, it can be seen that there are seven categories of ground subsidence factors. The depth and thickness of the overburden can affect the subsidence depending on the existence of the cavity, whereas the depth and orientation of the boundary between soil and rock are dominant factors in the ground composed of soil and rock. In case of soil layers, more various influencing factors exist such as type of soil, shear strength, relative density and degree of compaction, dry unit weight, water content, and liquid limit. The type of rock, distance from the main fracture and RQD can be influential factors in the bedrock. When approaching from the hydrogeological point of view, the rainfall intensity, the distance and the depth from the main channel, the coefficient of permeability and fluctuation of ground water level can influence to ground subsidence. It is also possible that the ground subsidence can be affected by external factors such as the depth of excavation and distance from the earth retaining wall, groundwater treatment methods at excavation work, and existence of artificial facilities such as sewer pipes. It is estimated that to evaluate the ground subsidence factor during the construction of underground structures in urban areas will be essential. It is expected that ground subsidence factors examined in this study will contribute for the reliable evaluation of the ground subsidence risk.

• Journal of Korean Society of Steel Construction
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• v.26 no.1
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• pp.43-53
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• 2014

A single plate connection(SPC) consists of a plate welded to the columns and bolts connected to the beam web. The SPC is widely used for a simple shear connection of steel structure because it is easy-to-fabricated, easy-to-installed and economical. The conventional SPC is used for 2 to 12 bolts in a single vertical row. It is designed to limit the plate thickness by bolt diameter to obtain flexible and ductile connections. The design strength for eccentric shear shall be the lesser of the shear strength of bolts or bearing strength of plate and when the design strength is decided by edge distance failure, the results can be very conservative. Although the research on special solution for 'weak-plate/strong-bolt' model with 2 to 4 bolts has been conducted by L. S. Muir, and W. A. Thonton, 2004, study on generalized design procedures did not conduct. This study proposed design procedure for evaluation of the design strength of eccentric shear bolt groups on a single plate connection based on the actual edge distance and the direction of bolt reaction forces by using elastic vector method(EVM) and instantaneous center of rotation method(ICM).

• Journal of the Korean Institute of Gas
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• v.25 no.6
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• pp.7-13
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• 2021

Various research has been done on fires and explosions at gas stations at home and abroad. However, only studies of off-site damage in the event of fire at the gas station were conducted, and research on fire at the auxiliary facilities in the gas station was insufficient. The gas station is a place where anyone can easily access dangerous goods. As the risk of fire increases due to the recent increase of auxiliary facilities such as convenience stores and car repair shops in gas stations, it is important to detect the effects of fire on the main oil refinery in case of fire and to verify the validity of existing regulations. In this thesis, we conducted a study to find out the effect of radiation heat on the separation between fixed and fixed oil reactors in the event of fire at an auxiliary facility. Simulation was modelled using FDS 5.5.3 Version, and the size of the fire source was configured with 13 fire assessment devices and the heat emission rate per unit area was entered. Simulation shows that the separation distance of 2 m does not secure the safety of the gas pump in the event of fire at the auxiliary facilities, and radiation heat does not damage at the separation distance of at least 4 m. Accordingly, facilities that can block radiant heat in the event of fire at auxiliary facilities, and measures to limit the use of auxiliary facilities or to re-impose the separation between buildings and fixtures will be needed.