• Journal of Korea Water Resources Association
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• v.40 no.1 s.174
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• pp.11-24
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• 2007

There exist various difficulties in runoff analysis due to many ungauged basins in Korea and the runoff phenomena is also more and more complicated by the change of geologic characteristics due to the urbanization. So, we use GIS technique which is widely used in hydrologic field and cell runoff concept for the fast and effective runoff simulation. This study uses the observations of 6 stage stations in Wi-Cheon watershed and simulates the watershed parameters by using WMS model. We construct DEM by the grids which are consisted based on the criteria of minimum area according to land use. The cell runoff is estimated by an average weighted method using mean annual streamflow and mean maximum daily streamflow obtained from six stage stations. The runoff ratio at arbitrary site is estimated by conducting the direction analysis of streamflow and by removing sinkhole. We compare the simulated and observed runoffs and know that the simulated runoff shows the valid results. So, we could use the geographical information and cell runoff concept for more fast and effective runoff simulation studies.

• The Korean Journal of Petroleum Geology
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• v.14 no.1
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• pp.12-20
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• 2008

Oil sands in Canada are representative example of unconventional resources whose reserve estimates are as large as those in Saudi Arabia. Typical reservoir rocks of oil sands consist of channel-related deposits formed in a tide-dominated depositional setting. The tidal deposits are commonly characterized by spatially complicated and heterogeneous properties. Successful engineering methods to develop oil sands require in-depth understanding in the spatial distribution of reservoir properties. Geological model for oil sand reservoir characterization can be built on the basis of comparative studies of ancient and modem analogues. In particular, modern analogue studies become increasingly indispensable, since they provide better understanding in the reservoir-rock forming process and more importantly in the external mechanism responsible for the reservoir heterogeneity. Tide-dominated environment along the west coast of Korea is considered as one of the most excellent modem analogues of oil-sand forming depositional environment. Korean tidal environment provides insights on the origin of mud breccia, facies and stratigraphic architecture which are key issues to the characterization of oil sand reservoirs.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.8
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• pp.1456-1464
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• 2007

The research of skin-tone detection has been conducting continuously to enlarge the importance in security, surveillance and administration of the information and 'Password Control System' for using face and skin recognition in airports, harbors and general companies. As well as tile rapid diffusion of the application range in image communications and an electron transaction using wide range of communication network, the importance of the accurate detection of skin color has been augmenting recently. In this paper, it will set up the boundaries of skin colors using the information of Cb and Cr in YCbCr color model of human skin color which is from hundreds compiled portrait images for each race, and suggest a efficient yet simple structure about the skin detection which has been followed by whether the comprehension of the boundaries of skin or not with adaptive skin-range set. With the possibility of the 1D Processes which does not use any memory, it is able to be applied to relatively small-sized hardware and system such as mobile apparatuses. To add the selective mode, it is not only available the improvement of tie skin detection, but also showing the correspondent results about previous face recognition technologies using complicated algorithm.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.11
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• pp.594-603
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• 2018

Recently, according to the development of measurement techniques, it has become possible to take complicated and time-consuming field measurements in a simple and convenient manner. In this background, this study estimated the tension of cables under ambient vibration using minimized measurement and signal processing. The VBDM using video-only by low-cost equipment was used as a minimized measurement. An estimation of the natural frequency using the mirror frequency concept was also proposed to solve the shortage of frequency band in this case. Furthermore, the FDD method was adopted for a natural frequency estimation in the ambient vibration related to field application. Experimental studies using a cable-stayed bridge model were carried out to examine the properties of the mirror frequency and the applicability of FDD with the proposed minimized system. The results showed that FDD for ambient vibration also works properly in an estimation of the natural frequency using the minimized system. In addition, the mirror frequency concept can allow a high natural frequency estimation even in a distorted signal by low-speed recording, which can overcome the limit of the minimized system. Overall, the proposed minimized system can be effective for the tension estimations of a cable under ambient vibration.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.1
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• pp.59-66
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• 2022

In order to solve the problem of urban traffic congestion, Urban Air Mobility (UAM) concept using Electric Vertical Take-off and Landing (eVTOL) aircraft has been gaining popularity, and many domestic and international studies are underway. However, since these aircraft inevitably fly over densely populated areas, it is essential to ensure safety, which starts with accurately analyzing the crash risk. In this paper, the locations and impact speeds of crash are computed using six degree-of-freedom simulations of an eVTOL aircraft in a fixed-wing mode. System malfunction was modeled by a sudden loss of thrust with control surfaces being stuck during cruise. Because most of these eVTOL aircraft are still under development, a methodology of constructing a six degree-of-freedom dynamics model from generic specification is also developed. The results show that the crash locations are highly concentrated right under the aircraft within a square that has an edge length similar to the cruise altitude. Speed distribution is more complicated because almost identical crash locations can be achieved by two very different paths resulting in a large variation in the speeds.

• Journal of the Korea Society for Simulation
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• v.18 no.3
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• pp.103-112
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• 2009

In a nuclear power plant (NPP), periodic sensor calibrations are required to assure sensors are operating correctly. However, only a few faulty sensors are found to be calibrated. For the safe operation of an NPP and the reduction of unnecessary calibration, on-line calibration monitoring is needed. In this paper, principal component-based Auto-Associative support vector regression (PCSVR) was proposed for the sensor signal validation of the NPP. It utilizes the attractive merits of principal component analysis (PCA) for extracting predominant feature vectors and AASVR because it easily represents complicated processes that are difficult to model with analytical and mechanistic models. With the use of real plant startup data from the Kori Nuclear Power Plant Unit 3, SVR hyperparameters were optimized by the response surface methodology (RSM). Moreover the statistical techniques are integrated with PCSVR for the failure detection. The residuals between the estimated signals and the measured signals are tested by the Shewhart Control Chart, Exponentially Weighted Moving Average (EWMA), Cumulative Sum (CUSUM) and generalized likelihood ratio test (GLRT) to detect whether the sensors are failed or not. This study shows the GLRT can be a candidate for the detection of sensor drift.

• Journal of the Korean Geotechnical Society
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• v.25 no.7
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• pp.35-46
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• 2009

Pressure grouting is a common technique in geotechnical engineering to increase the stiffness and strength of the ground mass and to fill boreholes or void space in a tunnel lining and so on. Recently, the pressure grouting has been applied to a soil-nailing system which is widely used to improve slope stability. The soil-nailing design has been empirically performed in most geotechnical applications because the interaction between pressurized grouting paste and the adjacent ground mass is complicated and difficult to analyze. The purpose of this study is to analyze the increase of pullout resistance induced by pressurized grouting with the aid of performing laboratory model tests and field tests. In this paper, two main causes of pullout resistance increases induced by pressurized grouting were verified: the increase of mean normal stress and the increase of coefficient of pullout friction. From laboratory tests, it was found that dilatancy angle could be estimated by modified cavity expansion theory using the measured wall displacements. The radial displacement increases with dilatancy angle decrease and the dilatancy angle increases with injection pressure increase. The measured pullout resistance obtained from field tests is in good agreement with the estimated one from the modified cavity expansion theory.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.1A
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• pp.11-19
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• 2006

In this study ship collision risk analysis is performed to determine the design vessel for collision impact analysis of suspension bridge. Method II in AASHTO LRFD bridge design specifications which is a more complicated probability based analysis procedure is used to select the design vessel for collision impact. From the assessment of ship collision risk for each bridge pier exposed to ship collision, the design impact lateral strength of bridge pier is determined. The analysis procedure is an iterative process in which a trial impact resistance is selected for a bridge component and a computed annual frequency of collapse(AF) is compared to the acceptance criterion, and revisions to the analysis variables are made as necessary to achieve compliance. The acceptance criterion is allocated to each pier using allocation weights based on the previous predictions. This AF allocation method is compared to the pylon concentration allocation method to obtain safety and economy in results. This method seems to be more reasonable than the pylon concentration allocation method because AF allocation by weights takes the design parameter characteristics quantitatively into consideration although the pylon concentration allocation method brings more economical results when the overestimated design collision strength of piers compared to the strength of pylon is moderately modified. The design vessel for each pier corresponding with the design impact lateral strength obtained from the ship collision risk assessment is then selected. The design impact lateral strength can vary greatly among the components of the same bridge, depending upon the waterway geometry, available water depth, bridge geometry, and vessel traffic characteristics. Therefore more researches on the allocation model of AF and the selection of design vessel are required.

• Genomics & Informatics
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• v.21 no.3
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• pp.33.1-33.11
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• 2023

Type 2 diabetes mellitus (T2DM) is a multifactorial, polygenic, and metabolically complicated disease. A large number of genes are responsible for the biogenesis of T2DM and calpain10 (CAPN10) is one of them. The association of numerous CAPN10 genetic polymorphisms in the development of T2DM has been widely studied in different populations and noticed inconclusive results. The present study is an attempt to evaluate the plausible association of CAPN10 polymorphism SNP-19 (rs3842570) with T2DM and T2DM-related anthropometric and metabolic traits in the Noakhali region of Bangladesh. This case-control study included 202 T2DM patients and 75 healthy individuals from different places in Noakhali. A significant association (p < 0.05) of SNP-19 with T2DM in co-dominant 2R/3R vs. 3R/3R (odds ratio [OR], 2.7; p=0.0014) and dominant (2R/3R) + (2R/2R) vs. 3R/3R (OR, 2.47; p=0.0011) genetic models was observed. High-risk allele 2R also showed a significant association with T2DM in the allelic model (OR, 1.67; p=0.0109). The genotypic frequency of SNP-19 variants showed consistency with Hardy-Weinberg equilibrium (p > 0.05). Additionally, SNP-19 genetic variants showed potential associations with the anthropometric and metabolic traits of T2DM patients in terms of body mass index, systolic blood pressure, diastolic blood pressure, total cholesterol, and triglycerides. Our approach identifies the 2R/3R genotype of SNP-19 as a significant risk factor for biogenesis of T2DM in the Noakhali population. Furthermore, a large-scale study could be instrumental to correlate this finding in overall Bangladeshi population.

• Korea Trade Review
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• v.48 no.2
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• pp.45-69
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• 2023

The advent of the 4th industrial technology brought about various changes and innovations in the overall industry, but the digitalization of the logistics industry, which involved complicated paperwork processes and various stakeholders, was somewhat behind compared to other industries. However, changes and innovations related to digitalization in the logistics industry began to accelerate due to the impact of COVID-19. This study is to check the digitalization status of container liners accelerated by these changes, analyze the impact of such changes on customer satisfaction and behavioral intention. In this study, a questionnaire survey was conducted for 30 days targeting workers in the logistics industry who had experience using digitalization products of container shipping companies, and a total of 144 questionnaire responses were used to verify hypotheses. To summarize the results of this study, first, it was confirmed that perceived ease of use has a positive (+) effect on perceived usefulness. Second, perceived ease of use was found to have a positive (+) effect on customer satisfaction. Third, it was found that perceived usefulness had a positive (+) effect on customer satisfaction. Fourth, perceived usefulness has a positive (+) effect on behavioral intention. Fifth, it was found that customer satisfaction had a positive (+) effect on behavioral intention. Summarizing the results of the study, it can be summarized that the digitization of regular shipping companies is convenient to use and has a positive effect on customer satisfaction and behavioral intention if it is useful.