• Ocean Systems Engineering
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• v.7 no.2
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• pp.107-120
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• 2017

Spud-can is used for fixing jack-up rig on seabed. It needs to be inserted up to the required depth during the installation process to secure enough soil reaction and prevent overturning accidents. On the other hand, it should be extracted from seabed soils as fast as possible during the extraction process to minimize the corresponding operational cost. To achieve such goals, spud-can may be equipped with water-jetting system including monitoring and control. To develop such a smart spud-can, a reliable numerical simulation tool is essential and it has also to be validated against physical model tests. In this regard, authors developed a numerical simulation tool by using a commercial program ANSYS with extended Drucker-Prager (EDP) formula. Authors also conducted small-scale (1/100) physical model tests for verification and calibration purpose. By using the numerical model, a systematic parametric study is conducted both for sand and K(kaolin)-clay with varying important soil parameters and the best estimated soil properties of the physical test are deduced. Then, by using the selected soil properties, the numerical and experimental results for a sand/K-clay multi-layer case are cross-checked to show reasonably good agreement. The validated numerical model will be useful in the next-stage study which includes controllable water-jetting.

• Journal of Wetlands Research
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• v.10 no.3
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• pp.99-109
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• 2008

This research focused on analyzing and comparing between the results of hydraulic physical modeling and the results of numerical modeling of continuous block system in river bank protection which is newly developed in-situ block system. To verify the hydraulic physical modeling and review the effectiveness, the numerical modeling was needed against the model test results for vegetation application or not. HEC-RAS model was for 1 dimensional numerical analysis and SMS was for 2 dimensional numerical analysis. The results of the two dimensional numerical simulation, under the condition of roughness coefficient calibration, show similar and rational consequence against the physical modeling. These satisfactory results show that the accomplished results of hydraulic modeling and the predicted results of numerical modeling corresponded reasonably each others.

• Journal of Acupuncture Research
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• v.38 no.2
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• pp.140-145
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• 2021

Background: Aconitum sinomontanum Nakai (ASN) has been reported to have analgesic effects. In this study an animal model of pharmacopuncture using ASN (100-500 mg/kg) was examined. Methods: Sprague-Dawley (SD) rats (n = 40) were randomly assigned to ASN-Low (1 mg/mL, 1.8 mL, ASN-L), ASN-Intermediate (5 mg/mL, 1.8 mL, ASN-M), ASN-High (10 mg/mL, 1.8 mL, ASN-H), negative control (0.2 mL normal saline), and positive control (0.2 mL 0.5% lidocaine) groups. All experiments were administered to the rats' left hind leg. The analgesic response was assessed by monitoring the physical (hot plate, and von Frey test) and chemical (formalin) responses to pain. Results: All ASN pharmacopuncture groups demonstrated significant differences in pain response to the hot plate test, von Frey test, and formalin test, compared to the control group (p < 0.05). The response of the ASN-M group and ASN-H groups to the hot plate, the formalin, and the von Frey tests were significantly different, compared to the lidocaine group (p < 0.05). Conclusion: ASN pharmacopuncture had a significant analgesic effect on SD rats in response to physical and chemical models of pain.

• Journal of the Society of Naval Architects of Korea
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• v.60 no.6
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• pp.450-459
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• 2023

According to Korea Maritime Safety Tribunal, there have been 14,100 maritime accidents from 2017 to 2021. Among those accidents, ship collision accidents have been up to 1,275 cases. But in the accidents relating to small ships like a fishing vessel, analyzing the causes of the accidents would depend on statements of the persons related because there is often no navigational data. But those statements can be incorrect and give rise to disagreements between them so that it causes conflicts with each other during the trial. So a replay system of ship collision accident (RESCA) has been developed in order to reproduce the ship collision accident by using AIS, V-PASS or radar data. But the reproduced trajectory of ship collision accident is needed to be verified because it can be unreasonable physically. So a method to verify the reproduced trajectory and collect the physical data on ship collision accident is newly designed by using free running test. In the RESCA, the accident is reproduced using the navigational data from the trajectory for a ship and measured from free running model test for the other ship at the same time. Through free running test, the behavior of the model ship is transformed from model scale into real scale. In order to check into the accuracy of the new method, free running model tests by using RESCA are carried out on the actual ship collision accidents.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.2
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• pp.64.2-64.2
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• 2016

Optical variability is one way to probe the nature of the central engine of AGN at smaller linear scales and previous studies have shown that optical variability is more prevalent at longer timescales and at shorter wavelengths. Especially, intra-night variability can be explained through the damped random walk model but small samples and inhomogeneous data have made constraining this model hard. To understand the properties and physical mechanism of optical variability, we are performing the KMTNet Active Nuclei Variability Survey (KANVaS). Test data of KMTNet in the COSMOS field was obtained over 2 separate nights during 2015, in B, V, R, and I bands. Each night was composed of 5 and 9 epochs with ~30 min cadence. To find AGN in the COSMOS field, we applied multi-wavelength selection methods. Different selection methods means we are looking different region in unification model of AGN, and 100~120, 400~500, 50~100 number of AGN are detected in X-ray, mid-infrared, and radio selection of AGN, respectively. We performed image convolution to reflect seeing fluctuation, then differential photometry between the selected AGN and nearby stars to achieve photometric uncertainty ~0.01mag. We employed one of the standard time-series analysis tools to identify variable AGN, chi-square test. Preliminarily results indicate that intra-night variability is found for X-ray selected, Type1 AGN are 23.6%, 26.4%, 21.3% and 20.7% in the B, V, R, and I band, respectively. The majority of the identified variable AGN are classified as Type 1 AGN, with only a handful of Type 2 AGN showing evidence for variability. The work done so far confirms that there are type and wavelength dependence of intra-night optical variability of AGN.

• Journal of Preventive Medicine and Public Health
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• v.36 no.1
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• pp.11-23
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• 2003

Objectives : The 1990s has seen advances in the conceptualization of self-perceived health status which has important roles for individual health and the quality of life. Many types of standardized questionnaires have been developed with the current wide use of SF-36, NHP, andEuroQol. However, the outcomes of these tools may be different with regard to regional, cultural and emotional backgrounds. The purpose of this study was to trial the development of a Korean Health Profile (KHP 1.0) to measure the self-perceived health stati of Koreans. Methods : The KHP 1.0 was designed on the basis of the Medical Outcome Study Form 36 (SF-36), the Nottingham Health Profile (NHP), and the EuroQOL. It was composed of 9 scales; physical functioning, role limitation-physical, pain, general health, energy, social isolation, sleep, role limitation-emotional, and e-motional health. Self-reported chronic disease conditions, and the Zung's Self-Rating Depression Scale (SDS), were also checked for the evaluation of clinical validity. This study was conducted, from December 2000 to January 2001, on 800 middle-aged parents, with four high school students, with 100 retest sets being conducted two weeks later. From the 800 subjects there were 588 complete responses (effective response 73.5%). The reliability of the test-retest results, and the factor analysis on the validity of the KHP 1.0 components, were evaluated using the SPSS (ver 10.0) software. Results : The reliability of the KHP 1.0 was good with Cronbach's alpha (>0.6), test-retest correlation coefficients (>0.5), but with no significant differences from the paired t-test. From the psychometric validity tests, the 9 scales of the KHP 1.0 were divided into two components; physical and mental, and trimmed to the established model with 55% of the total variance, with the exception of role limitation-emotional. The clinical validity on the basis of the comparison for the four characteristic groups; healthy, physical conditions only, mental conditions only, and physical and mental conditions were also good. Conclusions : The KHP 1.0 appears to be a valid measurement tool of self-perceived health stati of Koreans, although there are limitations, i.e. sample size was too small, a limited number of middle-aged subjects, and it was based on unconfirmed diagnoses, etc. Therefore, further study is required to standardize the assessment.

• Journal of IKEEE
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• v.20 no.1
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• pp.94-102
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• 2016

This paper proposes a new prediction method to reduce times and labor of repetitive multi-physics simulation. To achieve exact results from the whole simulation processes, complex modeling and huge amounts of time are required. Current multi-physics analysis focuses on the simulation method itself and the simulation environment to reduce times and labor. However this paper proposes an alternative way to reduce simulation times and labor by exploiting machine learning algorithm trained with data set from simulation results. Through comparing each machine learning algorithm, Gaussian Process Regression showed the best performance with under 100 training data and how similar results can be achieved through machine-learning without a complex simulation process. Given trained machine learning algorithm, it's possible to predict the result after changing some features of the simulation model just in a few second. This new method will be helpful to effectively reduce simulation times and labor because it can predict the results before more simulation.

• The Journal of Korean Medicine
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• v.37 no.2
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• pp.76-84
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• 2016

Objectives: We evaluated the anti-fatigue effects of Rh2-enriched Korean ginseng (Ginseng Rh2+) using a forced exercise-induced chronic fatigue mouse model. Methods: ICR male mice were subjected to running wheel for 1 h, 5 days/week during 4 weeks, and running velocity was gradually increased. Each running session was followed by oral administration of distilled water, Ginseng Rh2+ (150 or 300 mg/kg), or N-acetyl-L-cysteine (NAC, 100 mg/kg) 1 h later. The exercise tolerance and forced swimming test were performed to evaluate the fatigue condition. Results: Chronic forced exercise reduced the physical activity, as evidenced by the behavioral tests, which were notably ameliorated by Ginseng Rh2+ treatment. Ginseng Rh2+ treatment also attenuated the alterations of energy metabolism and oxidative stress in skeletal muscle tissues and/or sera, including malondialdehyde (MDA), lactate concentration and its related factors (lactate dehydrogenase, blood urea nitrogen, and glucose levels). Conclusion: These findings strongly suggest that Ginseng Rh2+ exerts a potent anti-fatigue effect through modulation of energy metabolism and oxidative response.

• Journal of The Korean Society of Integrative Medicine
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• v.2 no.4
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• pp.91-100
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• 2014

Purpose : The purpose of this experiment is to find out the effectiveness which exert influence on cognitive skills by using the Driver Rehabilitation program for senior citizens who are over 65 years old and live in Busan. Method : From July first, 2014 to August 28th, 2014, we researched the 60 elderly people who are over 65 and go to community relief center which is in Busan. - 30 are experimental group and the other is control group. In the experimental group, we used Nintendo wii's driving simulation program and RC Car driving program in the model road. For estimation, we used MVPT-3(Motor-Free Visual Perception Test-3), Trail Making Test - 1, Trail making Test - 2 and LOTCA(Loewenstein Occupational Therapy Cognitive Assessment). Result : Nintendo wii's driving simulation program and RC Car driving program in model road results efficient visual perception ability. This programs results effectively in visual perception ability and space perception ability. This programs results effectively in motor apraxia ability. This programs results effectively in control ability for visual perception. This programs results effectively in thinking operation. Conclusion : Nintendo Wii's driving simulation program and RC Car driving program in model road positively influence improving for visual perceptual ability and cognitive function of elderly people. Also it is considered as being more efficient for improving visual perceptual ability and cognitive function to implement basic rehabilitation training with driving rehabilitation program than basic training itself.

• Geomechanics and Engineering
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• v.27 no.6
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• pp.551-560
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• 2021

Due to the low strength and high compressibility characteristics, the loess deposits tunnels are prone to large deformations and collapse. An accurate stability evaluation for loess deposits is of considerable significance in deformation control and safety work during tunnel construction. 37 groups of representative data based on real loess deposits cases were adopted to establish the stability evaluation model for the tunnel project in Yan'an, China. Physical and mechanical indices, including water content, cohesion, internal friction angle, elastic modulus, and poisson ratio are selected as index system on the stability level of loess. The data set is randomly divided into 80% as the training set and 20% as the test set. Firstly, principal component analysis (PCA) is used to convert the five index system to three linearly independent principal components X1, X2 and X3. Then, the principal components were used as input vectors for probabilistic neural network (PNN) to map the nonlinear relationship between the index system and stability level of loess. Furthermore, Leave-One-Out cross validation was applied for the training set to find the suitable smoothing factor. At last, the established model with the target smoothing factor 0.04 was applied for the test set, and a 100% prediction accuracy rate was obtained. This intelligent classification method for loess deposits can be easily conducted, which has wide potential applications in evaluating loess deposits.