• Korean Journal of Applied Biomechanics
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• v.19 no.1
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• pp.37-47
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• 2009

This study develops a technique training program to enhance the completion of Kolman, the high air flight technique, and applies it to two national athletes of the horizontal bar, one of the gymnastic events, for eight weeks. After that, their improvement was measured through 3D motion analysis to help them elevate their performance. The training program includes swing, hand release, twist, and bar hold, and its implementation produced the results stated below. They were made to practice the motion in the following way. After the hand-standing of giant swing which initiates the motion, they lift their body upward a little bit more. Next, they take their body down almost like a vertical descent and make a deep tap swing. Instead of doing the tap swing which widens the flection of hip and shoulder joints, while body revolution is more emphasized in particular, they release the bar as raising the centroid of their body sufficiently. During the flight, they try to narrow every joint in their body. As a result, the bar's elasticity becomes greatly increased, and since the backing rate of their body gets higher, the centripetal force of the swing is improved that they can release the bar in the higher position. In addition, because they can erect their body faster during the flight, they can perform comfortable twist and revolution in the air. They can also adjust the direction of the flight easily without too much concern for the proper timing of hand release as they rise. Thereby, they can not only maintain adequate distance from the bar for the bar hold but also ensure enough distance for body revolution and twist.

• 한국지구물리탐사학회:학술대회논문집
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• 2008.10a
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• pp.51-56
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• 2008

The waveform inversion for isotropic media has ever been studied since the 1980s, but there has been few studies for anisotropic media. We present a seismic waveform inversion algorithm for 2-D heterogeneous transversely isotropic structures. A cell-based finite difference algorithm for anisotropic media in time domain is adopted. The steepest descent during the non-linear iterative inversion approach is obtained by backpropagating residual errors using a reverse time migration technique. For scaling the gradient of a misfit function, we use the pseudo Hessian matrix which is assumed to neglect the zero-lag auto-correlation terms of impulse responses in the approximate Hessian matrix of the Gauss-Newton method. We demonstrate the use of these waveform inversion algorithm by applying them to a two layer model and the anisotropic Marmousi model data. With numerical examples, we show that it's difficult to converge to the true model when we assumed that anisotropic media are isotropic. Therefore, it is expected that our waveform inversion algorithm for anisotropic media is adequate to interpret real seismic exploration data.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.9 no.2
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• pp.161-168
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• 2015

In this paper, we present an inertial sensor-based gait distance measurement system using accelerometer, gyroscope, and magnetometer. To minimize offset and gain error of inertial sensors, we performed the calibration using the self-made calibration jig with 9 degrees of freedom. For measuring accurate gait distance, we used gradient descent algorithm to remove gravity error and used analysis of gait pattern to remove drift error. Finally, we measured a gait distance by double-integration of the error-removed acceleration data. To evaluate the performance of our system, we walked 10m in a straight line indoors to observe the improvement of removing error which compared un-calibrated to calibrated data. Also, the gait distance measured by the system was compared to the measurement of the Vicon motion capture system. The evaluation resulted in the improvement of $31.4{\pm}14.38%$(mean${\pm}$S.D.), $78.64{\pm}10.84%$ and $69.71{\pm}26.25%$ for x, y and z axis, respectively when walked in a straight line, and a root mean square error of 0.10m, 0.16m, and 0.12m for x, y and z axis, respectively when compared to the Vicon motion capture system.

• Journal of the Korean Society for Railway
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• v.18 no.4
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• pp.309-316
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• 2015

The contribution of exterior devices such as bogie fairings and pantographs to running resistance was estimated on the basis of coasting tests at up to 350 km/h with the help of the Korean Next Generation High speed train (HEMU-430X). In order to assess the reduction of air resistance by nose car's bogie fairing, coasting tests were conducted with a removable bogie fairing at various speed ranges. And, the contribution of the pantograph to air resistance was also estimated with coasting tests that include the pantograph's rising and descent modes. The linear regression method was used to examine decelerations from time-velocity data and the equation of resistance to motion is proposed from the deceleration data. From the aerodynamic term of the equation of resistance to motion, the contribution to air resistance by nose car's bogie fairing and pantograph was estimated. The results show that the air resistance was reduced by about 3.8% by the nose car's bogie fairing. And, the 3.9% increase of air resistance by the pantograph (open knee mode) has been found.

• Journal of Acupuncture Research
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• v.17 no.3
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• pp.219-232
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• 2000

Objective : The meridian and the acupuncture point of oriental medicine are very important in the department of acupuncture and moxibustion. Recently, we needed to study on the phenomenon of the meridian and acupuncture point with objective data. And then, I made a study of effects on the thermal changes of Five-shu-points(五輸穴) of the Lung meridian with acupuncture on Taeyon($L_9$, 太淵), using Digital infrared thermal imaging(D.I.T.I). Method : This study researched into clinical statistics for 60 men who are in good health. The objective was divided into two groups, one was the control group(CON, N=30) and the other was acupuncture group(ACU, N=30). The first, I took a picture for 60 men with the Digital infrared thermal imaging(D.I.T.I.). After 10 minutes, I took a second picture for each group following experimental methods. Results : I. The Mean temperature of Sasang($L_{11}$), Oje($L_{10}$), Taeyon($L_9$), Kyonggo($L_8$), Choldaek($L_5$) and Taenung($P_7$) area in adult men with good health, made a no significant difference with left and right side points. 2. Acupuncture group with acupuncture stimularion on Taeyon($L_9$) had a effect on much thermal changes of Sasang($L_{11}$), Oje($L_{10}$), Taeyon($L_9$), Kyonggo($L_8$) and Choldaek($L_5$) than control group. The thermal changes of the area which is a meridian point in the Lung Meridian of acupuncture group differed from control group with significant decrease and increase following the decreasing or increasing temperature class. Each class of ascent and descent thermal change was statistically significant value compared with control group. 3. Acupuncture group with acupuncture stimulation on Taeyon($L_9$) had not a effect on thermal changes of Taenung($P_7$) area than control group. And the increasing and decreasing temperature class of the acupuncture group did not significantly differ from control group. Conclusion : I could think that the acupuncture on Taeyon($L_9$) affected the thermal change of the area which is the Five-shu-points in the Lung Meridian. And then I could relate these results with the existence of the meridian and acupuncture point.

• KOMUNHWA
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• no.70
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• pp.17-34
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• 2007

Jigangkooksa's Monument at Beopchonsa is a monument representing the Goryeo Era, registered as the National Treasure No. 59. Haerin was a descent of a small regional clan, who overcame a number of challenges to become the leader of the nation at the age of 75. The tower and monument built after his death are among the finest works of the Goryeo Era. The Yongwha-world of the Jigangkooksa's Monument is the expression of a new utopia, which cannot be found in numerous Buddhist arts including Buddhist holy picture's art or other Codex. After passing through the pillar of cloud where 4 heavenly birds play, the new world of vault unfolds. Below are the 13 mountains which stand for 13th Heaven. In the center stands Tusita, the sky. On the top of Tusita is a Nagapuspa. The Nagapuspa in general has wooden pillars of treasure dragon patterns with dragonhead-shaped flowers on top. On the bottom, indrajala hang down. The Yongwha-world of the Jigangkooksa's Monument is carved with patterns related to Maitreya entering Nirvana. Jigangkooksa was active in the Moonjong Kingdom, the most prosperous times of the Goryeo Era, and led the publication of the Buddhism's Collection of Sacred Writings, the holiest work of the Goryeo people. At the time, people have offered on his tower a picture of him as the owner of Yongwha-world, with the utmost respect. This was the ideal utopia perceived by the people of Goryeo.

• Journal of the Korean Geographical Society
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• v.46 no.6
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• pp.673-692
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• 2011

Advances in computer technology have enabled us to develop and use numerical landscape evolution models (NLEMs) for exploring the dynamics of geomorphic system from a variety of viewpoints which previously could have not been taken. However, as of yet there have been no trials using or developing NLEMs in Korea. The purpose of this research is to develop a 2 dimensional NLEM on a geological time scale and evaluate its usefulness. The newly developed NLEM (ND-NLEM) treats bedrock weathering as one of the major geomorphic processes and attempts to simulate the thickness of soil. As such it is possible to model the weathering-limited as well as the transport-limited environment on hillslopes. Moreover the ND-NLEM includes not only slow and continuous mass transport like soil creep, but also rapid and discrete mass transport like landslides. Bedrock incision is simulated in the ND-NLEM where fluvial transport capacity is large enough to move all channel bed loads, such that ND-NLEM can model the detachment-limited environment. Furthermore the ND-NLEM adopts the D-infinity algorithm when routing flows in the model domain, so it reduces distortion due to the use of the steepest descent slope flow direction algorithm. In the experiments to evaluate the usefulness of the ND-NLEM, characteristics of the channel network observed from the model results were similar to those of the case study area for comparison, and the hypsometry curve log during the experiment showed rational evidence of landscape evolution. Therefore, the ND-NLEM is shown to be useful for simulating landscape evolution on a geological time scale.

• Korean Journal of Biological Psychiatry
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• v.27 no.1
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• pp.18-26
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• 2020

Objectives The aim was to find effective vectorization and classification models to predict a psychiatric diagnosis from text-based medical records. Methods Electronic medical records (n = 494) of present illness were collected retrospectively in inpatient admission notes with three diagnoses of major depressive disorder, type 1 bipolar disorder, and schizophrenia. Data were split into 400 training data and 94 independent validation data. Data were vectorized by two different models such as term frequency-inverse document frequency (TF-IDF) and Doc2vec. Machine learning models for classification including stochastic gradient descent, logistic regression, support vector classification, and deep learning (DL) were applied to predict three psychiatric diagnoses. Five-fold cross-validation was used to find an effective model. Metrics such as accuracy, precision, recall, and F1-score were measured for comparison between the models. Results Five-fold cross-validation in training data showed DL model with Doc2vec was the most effective model to predict the diagnosis (accuracy = 0.87, F1-score = 0.87). However, these metrics have been reduced in independent test data set with final working DL models (accuracy = 0.79, F1-score = 0.79), while the model of logistic regression and support vector machine with Doc2vec showed slightly better performance (accuracy = 0.80, F1-score = 0.80) than the DL models with Doc2vec and others with TF-IDF. Conclusions The current results suggest that the vectorization may have more impact on the performance of classification than the machine learning model. However, data set had a number of limitations including small sample size, imbalance among the category, and its generalizability. With this regard, the need for research with multi-sites and large samples is suggested to improve the machine learning models.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.27 no.1
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• pp.9-16
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• 2014

Using a level set method and topological derivatives, a topological shape optimization method that is independent of an initial design is developed for linearly elastic structures. In the level set method, the initial domain is kept fixed and its boundary is represented by an implicit moving boundary embedded in the level set function, which facilitates to handle complicated topological shape changes. The "Hamilton-Jacobi(H-J)" equation and computationally robust numerical technique of "up-wind scheme" lead the initial implicit boundary to an optimal one according to the normal velocity field while minimizing the objective function of compliance and satisfying the constraint of allowable volume. Based on the asymptotic regularization concept, the topological derivative is considered as the limit of shape derivative as the radius of hole approaches to zero. The required velocity field to update the H-J equation is determined from the descent direction of Lagrangian derived from optimality conditions. It turns out that the initial holes are not required to get the optimal result since the developed method can create holes whenever and wherever necessary using indicators obtained from the topological derivatives. It is demonstrated that the proper choice of control parameters for nucleation is crucial for efficient optimization process.

• Journal of Sasang Constitutional Medicine
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• v.10 no.2
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• pp.283-290
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• 1998

Sasang Constitutional Medicine focuses on the different constitutional manifestations of the individual's nature and emotions. The nature and emotions drive the ascending and descending of Qi in the body. And this dynamics of the Qi's ascent and descent shapes the different types of structures, functions and temperaments. Although Sasang Constitutional Medicine has many advantages, its diagnosis of the constitution still depends on the doctors' own idea and has no objective identification. So many doctors in Korea have been trying to solve this problem. Recently, there are several efforts to find out the relationship between genetic information and constitution. By the way, May, 1998 there is a astonishing report about the gene which determines the human performance, that is ACE(angiotensin converting enzyme). And it suggests that the I allele was associated with improved endurance performance. ACE has three genotype including II, ID and DD. "I" means insertion and "D" means deletion. We determined the type of the Sasang constitution with QSCCII questionaire and the one's ACE genotype with PCR of the 127 people and we discovered the relationship between the constitution and the ACE genotype. The result is as follow. Among 39 people who have the II genotype, 7(18%) belong to Taeum(Taiyin), 9(23.1%) belong to Soyang(Shaoyang) and 23(59%) belong to Soeum(Shaoyin). Among 62 people who have the ID genotype, 18(29%) belong to Taeum(Taiyin), 21(33.9%) belong to Soyang(Shaoyang) and 23(37.1%) belong to Soeum(Shaoyin). Among 26 people who have DD genotype, 11(42.3%) belong to Taeum(Taiyin), 4(15.4%) belong to Soyang(Shaoyang) and 11(42.3%) belong to Soeum(Shaoyin). This data indicates that there are implicable relationship between the Sasang constitution and ACE genotype. Especially people who have II genotype have much possibility to be a Soeum(Shaoyin) person (59%) and Soyang(Shaoyang) person have less possibility to have DD genotype (15.4%). With this conclusion, we suggest further study of relationship between the Sasang constitution and ACE genotype and we think that other polymorphism can be a candidate of the partner of Sasang constitution.