• Journal of Preventive Medicine and Public Health
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• v.30 no.2 s.57
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• pp.392-401
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• 1997

Generally working environment and worker's health status of small scale industries (SSI) which employ less than 50 workers are known to be poorer than those of large scale industries(LSI) which employ more than 500 workers. However, according to the analysis of occupational injuries in Korea, prevalence rate of occupational injuries of SSI was 3.1 times as high as LSI. But there was no difference in prevalence rate of occupational disease and werkers with suspected occupational disease(D1) between SSI and LSI. To confirm these two different facts, we surveyed working environment and worker's health status of SSI and LSI in Kyeungin industrial complex. Workers in SSI were 10,878 and workers in LSI were 8,291 and number of hazardous agents in SSI were 3,554 and those of LSI were 1,916. We found following results. First, proportion of male workers and workers who were less than 30 yens old and more than 50 yens old was higher in SSI compared to LSI. Second, worker in SSI had more liver disease, viral hepatitis, and pneumoconiosis than in LSI, and there were more worker with suspected occupational disease, general disease, and worker needed close observation in SSI. But these effects had not statistical significance under the condition controlled by age and sex with logistic regression. Third, the numbers measured for specific chemicals, organic solvents, and heavy metals in SSI was more than in LSI. However there was on difference in the excess rate of each hazardous agent between SSI and LSI. As the above results workers' health status in SSI was poorer than in LSI, but these results were mainly due to the population structure difference. Although there were some limitation of this study and problems of sensitivity and validity for periodic health examination and working environment evaluation method, the concept that working environment and worker's health status in SSI should be reviewed. In future the study that will reveal the real weak point of SSI should be performed.

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.6
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• pp.148-156
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• 2018

The integrity assessment of the bridge behavior is generalized by field data of a static load-deformation curve and dynamic properties such as impact factors and natural frequencies. Evaluating it with numerical analysis is a reasonable method. The results of the mockup test and the numerical analysis are corresponded with each other since the behavior of service load proceeds in elastic region. In case of the dynamic behavior of structure, especially for the analysis of vibration, the result of the mockup test differs from the result of numerical analysis a little due to the geometric shape and non-homogeneous materials. In order to converge on these tolerances, this study suggested several numerical models, analyzed the sensitivity and finally offered a practical modeling method for the estimation of bridge on the basis of the result of mockup test. Based on the model substituted concrete section for strands section, the natural frequency of the model composed with axial stiffness of strands or the model applied the modified modulus of elasticity was closest with the result of the mockup test.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.04a
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• pp.32-32
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• 2019

Mutation breeding is the useful tool to improve agronomic traits in various crop species. Soybean is most important crop and is rich in protein and oil contents. Despite of the importance as economic value and various genetic resource of soybean, there have been limited studies of genetic relationship among mutant resources through radiation breeding. In this study, the agronomical phenotype for selecting various genetic resources was evaluated in 528 soybean mutant lines. As a result, 210 soybean mutants with their original cultivars were selected with various traits. We named 210 selected lines as Mutant Diversity Pool (MDP). The genetic diversity and the relationship of the MDP were investigated using TRAP and TE-TRAP markers. In TRAP analysis, sixteen primer combination (PC)s were used and a total of 551 fragments were amplified. The highest (84.00%) and the lowest (32.35%) polymorphism levels were showed in PC MIR157B+Ga5 and B14G14B+Ga3, respectively. The mean of PIC values was 0.15 ranging from 0.07 in B14G14B+Sa12 to 0.23 in MIR157B+Sa4. Phylogenetic and population structure analysis indicated that the 210 MDP lines dispersed to four groups among the wild types and their mutants. The highest genetic diversity among populations was observed between lines Paldal and 523-7 (Fst=0.409), whereas the lowest genetic diversity was between population KAS360-22 and 94seori (Fst=0.065). AMOVA showed 11.583 (21.0%) and 43.532 (79.0%) variations in inter and intra mutant population, respectively. Overall, the genetic similarity of each intra mutant populations was closer than that of inter mutant population. A total of 408 fragments were amplified in the 210 MDP using twelve PCs of TE-TRAP markers that were obtained from a combination of three TIR sequence of transposable elements (MITE-stowaway; M-s, MITE-tourist; M-t, PONG). The highest (77.42%) and the lowest (56.00%) polymorphism levels were showed in PONG+Sa4 and PONG+Sa12, respectively. The mean of PIC values was 0.15 ranging from 0.09 in M-s+Sa4 and M-s+Ga5 to 0.21 in M-t+Ga5. AMOVA of M-s showed 2.209 (20%) and 8.957 (80%) variations in inter and intra mutant population, respectively. AMOVA of M-t showed 2.766 (18%) and 12.385 (82%) variations in inter and intra mutant population, respectively. AMOVA of PONG showed 3.151 (29%) and 7.646 (71%) variations in inter and intra mutant population, respectively. According to our study, the PONG had higher inter mutant population and lower intra mutant population. This mean was that for aspect of radiation sensitivity, M-s and M-t showed higher mobility than that of PONG. Our results suggest that the TRAP and the TE-TRAP markers may be useful for assessing the genetic diversity and relationship among soybean MDP and help to improve our knowledge of soybean mutation/radiation breeding.

• Composites Research
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• v.32 no.1
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• pp.65-70
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• 2019

The aircraft composites wing parts are usually integrated with adhesive or fastener. These laminated composites have weak interlaminar strength, which can lead to delamination. In order to compensate the disadvantages of laminated composites, it is possible to improve the strength, durability, shock and fatigue resistance by reinforcing the fiber in the thickness direction. In addition, using a single structure near-net-shape saves the manufacturing time and the number of fasteners, thus can reduce the overall cost of the composite parts. In this study, compression test, tensile test and open-hole tensile test are carried out for three structural architecture of 3D (three-dimensional) textile preforms: orthogonal(ORT), layer-to-layer(LTL) and through-the-thickness(TTT) patterns. Among these, the orthogonal textile composite shows the highest Young's modulus and strength in tensile and compression. The notch sensitivity of the orthogonal textile composite was the smallest as compared with UD (unidirectional) and 2D (two-dimensional) fabric laminates.

• Journal of Korean Tunnelling and Underground Space Association
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• v.25 no.1
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• pp.13-26
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• 2023

Recently, as the development of underground spaces has become active due to rapid urbanization and population density, interest in the ground behavior according to the construction of underground spaces is increasing. In large cities with high population density and many buildings, ground subsidence has a great impact on structures and there may be a risk of collapse, so the analysis of ground behavior due to underground construction is essential. Previous studies have been conducted on the subsidence pattern of the surface and the deformation of the tunnel when constructing the tunnel, but analysis has rarely been conducted by using actual topographic information. Therefore, this study analyzed the difference in ground behavior between the actual topography and the flat topography. As a result, it was confirmed that ground settlement occurs at higher elevations, such as in mountainous topography, and when the numerical analysis is performed considering topographical information, the crown settlement of the tunnel is up to about approx. It showed a difference of 10 mm, and it was found that the sensitivity was less in the case of displacement of tunnel wall compared to the crown settlement and ground settlement. The numerical analysis considering the actual GIS-based topographic information presented in this study can be used to obtain more accurate surface subsidence data to understand the behavior of the upper structure due to tunnel excavation.

• Journal of the Korean Geotechnical Society
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• v.22 no.6
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• pp.15-26
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• 2006

Although numerous investigations have been performed over the years to predict the behavior and bearing capacity of piles, the mechanisms are not yet entirely understood. The prediction of bearing capacity is a difficult task, because large numbers of factors affect the capacity and also have complex relationship one another. Therefore, it is extremely difficult to search the essential factors among many factors, which are related with ground condition, pile type, driving condition and others, and then appropriately consider complicated relationship among the searched factors. The present paper describes the application of Artificial Neural Network (ANN) in predicting the capacity including its components at the tip and along the shaft from dynamic load test of the driven piles. Firstly, the effect of each factor on the value of bearing capacity is investigated on the basis of sensitivity analysis using ANN modeling. Secondly, the authors use the design methodology composed of ANN and genetic algorithm (GA) to find optimal neural network model to predict the bearing capacity. The authors allow this methodology to find the appropriate combination of input parameters, the number of hidden units and the transfer structure among the input, the hidden and the out layers. The results of this study indicate that the neural network model serves as a reliable and simple predictive tool for the bearing capacity of driven piles.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.29 no.3
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• pp.139-152
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• 2024

This study conducted various sensitivity experiments to assess and improve the performance of low-resolution global ocean circulation models. The MOM6 (Modular Ocean Model Version 6), developed by the Geophysical Fluid Dynamics Laboratory, was utilized. We focused on analyzing the effects of implementing the ePBL (energetics based planetary boundary layer) mixed layer scheme, including tidal simulation, and applying hybrid vertical coordinate system on the simulation accuracy of ocean circulation. The results revealed that the ePBL scheme effectively mitigated excessive mixed layer thickness and high temperature biases in the equatorial Pacific, while tidal simulations contributed to improving the oceanic structures in the Yellow Sea and the East Sea. Additionally, the hybrid vertical coordinate system enabled more accurate simulations of the vertical structure of temperature and salinity, enhancing model performance. This study proposes specific approaches to enhance the accuracy of ocean circulation models, contributing to global ocean and climate modeling efforts.

• Journal of The Korean Astronomical Society
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• v.43 no.1
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• pp.9-23
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• 2010

In this paper we examined the association of Infrared Dark Cloud (IRDC) cores with YSOs and the geometric properties of the IRDC cores. For this study a total of 13,650 IRDC cores were collected mainly from the catalogs of the IRDC cores published from other studies and partially from our catalog of IRDC cores containing new 789 IRDC core candidates. The YSO candidates were searched for using the GLIMPSE, MSX, and IRAS point sources by the shape of their SED or using activity of water or methanol maser. The association of the IRDC cores with these YSOs was checked by their line-of-sight coincidence within the dimension of the IRDC core. This work found that a total of 4,110 IRDC cores have YSO candidates while 9,540 IRDC cores have no indication of the existence of YSOs. Considering the 12,200 IRDC cores within the GLIMPSE survey region for which the YSO candidates were determined with better sensitivity, we found that 4,098 IRDC cores (34%) have at least one YSO candidate and 1,072 cores among them seem to have embedded YSOs, while the rest 8,102 (66%) have no YSO candidate. Therefore, the ratio of [N(IRDC core with protostars)]/[N(IRDC core without YSO)] for 12,200 IRDC cores is about 0.13. Taking into account this ratio and typical lifetime of high-mass embedded YSOs, we suggest that the IRDC cores would spend about $10^4\sim10^5$ years to form high-mass stars. However, we should note that the GLIMPSE point sources have a minimum detectable luminosity of about $1.2 L_{\odot}$ at a typical IRDC core's distance of ~4 kpc. Therefore, the ratio given here should be a 100ver limit and the estimated lifetime of starless IRDC cores can be an upper limit. The physical parameters of the IRDC cores somewhat vary depending on how many YSO candidates the IRDC cores contain. The IRDC cores with more YSOs tend to be larger, more elongated, and have better darkness contrast than the IRDC cores with fewer or no YSOs.

• Journal of the Korean earth science society
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• v.37 no.3
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• pp.162-172
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• 2016

Since the Northridge earthquake in 1994 and the Kobe earthquake in 1995 occurred, the concept of performance based design has been introduced for designing various kinds of important structures and buildings. Uniform hazard spectra (UHS), with annual exceedance probabilities, corresponding to the performance level of each structure, are required for performance-based design. The probabilistic seismic hazard analysis was performed using spectral ground motion prediction equations, which were developed from both Korean Peninsula and Central and Eastern US region, and several seismotectonic models suggested by 10 expert panel members in seismology and tectonics. The uniform hazard spectra for 5 highly populated cities in Korea, with recurrence period of 500, 1,000, and 2,500 years using the seismic hazard at the frequencies of 0.5, 1.0, 2.0, 5.0, 10.0 Hz and Peak ground acceleration (PGA) were analyzed using the probabilistic seismic hazard analysis. The sensitivity analysis suggests that spectral ground motion prediction equations impact much more on seismic hazard than what seismotectonic models do. The uniform hazard spectra commonly showed a maximum hazard at the frequency of 10 Hz and also showed the similar shape characteristics to the previous study and related technical guides to nuclear facilities.

• Archives of design research
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• v.13 no.4
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• pp.95-103
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• 2000

In order to satisfy customers' desire that is becoming more diverse, and to create the unique character of a product in the fast changing social structure and living environment, today's designers have to make efforts to provide new ideas continuously. In the twentieth century, the development of design in various aspects could be possible through an epoch-making progress of technology and industrialization, and thus the meaning and style of design has changed differently according to the current of the times. The retro design, which borrows the designs and styles which were popular in the past and recreates the design of modern meaning and concept, is widely applied now and in the spotlight as a latest design trend. This phenomenon of revival style appears as an image that makes us recollect the past in various fields while being recognized as an another value of new sense. Considered from the history of style changes for the past 100 years, the automobile design, the most representative in product design fields, has gradually changed in its types according to continuous historical, social, and cultural changes and technological progress, while a variety of designs have been continuously presented. The recent current of automobile styles, according to the rapid progress of advanced scientific technology, shows the fast and various changes and the retro style is becoming a new trend arousing people's interests and reintroducing the past designs. The revival trend in automobile designs is expected to stimulate human sensitivity and restore humanity on a different level before the trend, and also expected to be recreated as a new design trend in modern sense, connecting us with the past culture and expanding the realms of future designs.