• The Journal of the Acoustical Society of Korea
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• v.15 no.6
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• pp.47-51
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• 1996

The Cylindrical Shell Equation is one of the fundamental tools in the study of the noise analysis in the cylindrical shell. Therefore, lot of the acousticians induced many cylindrical shell motion equations.[1] In the Reference[6], we introduced the newly induced cylindrical Shell Equation and Junger and Feit's shell equation[5], and computed the free wave number with the linear Equation with the supposed solution, in the case of the free motion of the shell. In this paper, we compared above cylindrical shell equations by using dispersion curve of free wave number and we describe the physical mean for the dispersion curve with ring-frequency and ring-extention-frequency. With this result, we proves the useful of a newly induced cylindrical shell equation and we can analyse the Structure-Borne Sound of the shell with this equation in the application.

• Annual Conference on Human and Language Technology
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• 1998.10c
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• pp.177-185
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• 1998

한글의 가로쓰기와 세로쓰기 체계의 상대적 효율성을, 글을 읽을 때 관찰되는 시선 이동을 측정하여 비교하였다. 실험 1에서는 동일한 글을 가로와 세로 방향으로 제시하고, 글을 읽는 동안 시선 운동(머리 운동과 안구 운동의 합)을 공막탐지코일법(scleral search coil method)으로 측정하였다. 가로글 읽기의 경우, 시선도약(saccade)의 크기가 더 컸으며, 동일한 크기의 도약운동을 비교할 때, 세로글 읽기에 비해 상대적으로 도약운동의 속도가 높았다. 평균 고정기간(fixation duration)은 글의 읽기 방향에 따른 유의미한 차이를 보이지 않았다. 시선 도약크기와 도약운동 속도에서의 차이는 가로글을 읽는 속도를 높여 글을 읽는 시선 이동의 효율성이 가로글에서 상대적으로 높았다. 실험 2에서는 팔의 읽기 방향에 따른 시선 이동 변수에서의 차이가 글자극의 독특한 자극 특성에 기인한 것인지 혹은 시각 및 안구 운동 체계에서의 차이를 반영하는 것인지를 결정하고자 하였는데, 의미정보가 없는 점자극을 수평과 수직방향으로 제시하고, 방향에 따른 시선 이동의 차이가 글자극을 사용한 경우와 동일하게 나타나는지를 보았다. 점자극에서도 수평 방향의 시선도 약 운동이 보다 크고 정확한 경향성이 있었다. 이 결과는 사람의 시각 운동 체계가 수평 방향의 시선 이동에 대해 선호성을 보이고 있으며, 이러한 시각 및 안구 운동 체계에서의 차이가 글을 읽는 행동에도 반영되고 있음을 보여준다.

• Journal of the Korean Magnetics Society
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• v.6 no.5
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• pp.281-286
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• 1996

For the accurate analysis of motional characteristics of electrical machines, it is needed to solve the motion equations together with the electromagnetic field equations. In this paper the sequential coupling of systems, the spring mass system and the electromagnetic system, is adopted. The induced current and the magnetic fields are calculated by finite element method(FEM) with given speed. And then, with the computed elec-tromagnetic force, the mechanical equations are solved by the Runge-Kutta method. The above two processes are repeated sequentially to obtain the time domain solutions. The resultant values are applied to the energy conservation law to prove the usefulness of the proposed sequential method.

• Journal of the Korea Convergence Society
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• v.11 no.4
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• pp.119-124
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• 2020

In this paper, in order to encourage the user's exercise, we presented an exercise goal that considers the user's weight and exercise state, and dealt with a study on an app that gives a goal using GPS information. Unlike the vague numbers and times suggested in the existing app, it is presented specifically with the surrounding buildings or structures using GPS information. In addition, to use competitive psychology to exercise encouragement, it shows the movement information of people connected to the app and allows users to use the competitive psychology to get the effect of exercising many people. The app creates coordinates of major buildings and sets markings using the Naver Map SDK location information to present specific targets. It is easy for users to get bored if they give a goal every time, and the boredom that the user feels decreases the interest in the exercise. In order to not to lose interest in athletic interest. the app switches to game mode and give a light goal that doesn't matter user's weight or exercise status, and rewards user for achieving the suggested goals. Game mode is added to app that connects a person's will to practice. It adds fun elements to create interest, and uses competitiveness to help you live a healthy life with a steady workout. Technically, to improve the accuracy of smart-phone map display using GPS and the tilt processing was to be able to display the exact location.

• Korean Journal of Applied Biomechanics
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• v.19 no.2
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• pp.323-336
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• 2009

The purpose of the current study was to research scientific basis and necessity of supplementary materials for field lesson out of golf swing teaching methods. As the subject of study, skillful tour pro golfers were chosen to reinterpret field lesson results for driver swing from the viewpoint of kinematics. In addition, through precise analysis, this study developed a case to verify the validity and error of field lesson. As a result, field lesson showed a slight difference among qualitative evaluation of kinematical analysis of techniques, subjects of study, and items. Accordingly, there was a little difference between two methods in view of evaluation of errors that 5 subjects of the study have shown. However, there was a significant difference in compensation to prevent causes of error and errors. Based on instructor's experience most errors could be evaluated. Therefore, feedback for error correction based on instructor's experience showed a significant difference from qualitative evaluation of kinematical analysis of techniques. In conclusion, the following are required for correct golf swing lesson; instant feedback through field lesson and qualitative evaluation of kinematical analysis of techniques to determine fundamental causes correctly.

• KIPS Transactions on Computer and Communication Systems
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• v.8 no.4
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• pp.93-102
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• 2019

As interest in wellness grows, There is a lot of research about monitoring individual health using wearable devices. Accordingly, a variety of methods have been studied to distinguish exercise from daily activities using wearable devices. Most of these existing studies are machine learning methods. However, there are problems with over-fitting on individual person's learning, data discontinuously recognition by independent segmenting and fake activity. This paper suggests a detection method for exercise activity based on the physiological response principle of heart rate up and down during exercise. This proposed method calculates activity intensity and heart rate from triaxial and photoplethysmography sensor to determine a heart rate recovery, then detects exercise by estimating activity intensity or detecting a heart rate rising state. Experimental results show that our proposed algorithm has 98.64% of averaged accuracy, 98.05% of averaged precision and 98.62% of averaged recall.

• Journal of Navigation and Port Research
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• v.45 no.1
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• pp.16-25
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• 2021

Hydrodynamic coefficients should be accurately estimated to predict the maneuverability of underwater vehicles. Various captive model tests have been performed as part of estimation methods for these coefficients. Estimating hydrodynamic coefficients related to roll motion is important because underwater vehicles are sensitive to changes of roll moment. In this research, a pure roll motion equipment was newly designed to simply estimate hydrodynamic coefficients with respect to roll motion. Roll motion was implemented through a brief mechanical mechanism. The principle of operation, application process, and system identification of the equipment are described. An analysis method of the pure roll test is also suggested. Repeated tests of the newly equipment were carried out to check its reproducibility.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.5
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• pp.63-70
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• 2023

In this paper, we propose a Mixed Reality based rehabilitation exercise solution with the goal of mitigating one of the most common chronic conditions among the elderly, musculoskeletal disorders. In modern society, as the number of elderly increases, more people engage in office work and engage in more sedentary activities. Due to repetitive work in the office, muscle strength decreases and this causes many difficulties in daily life. In this study, we developed a mixed reality based exercise platform to solve these chronic musculoskeletal diseases. VR is not appropriate for elderly because of dizziness. In addition, we developed a wearable sensor based on IMU and attached it to important parts of the upper body to motion tracking. We developed a algorithm synchronize to raw data from wearable sensor with in a vr avatar. Ederly can check in real time whether rehabilitation exercises are being performed accurately through the avatar.

• Journal of Korea Foundry Society
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• v.22 no.6
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• pp.299-303
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• 2002

수정된 SIMPLE법과 VOF의 결합으로 predictor-two step corrector-VOF라고 불리는 새로운 알고리즘이 주조 시 용탕 충전과정을 해석하기 위해 개발되었다. 운동량보존으로부터 유도된 새 2단계 속도 경계조건 처리법은 용탕의 자유표면을 추적하는 데 사용되었다. 본 연구에서는 2개의 예제 계산을 통해 계산정확도와 속도에 대한 Courant 수의 영향을 살펴보았다. 그 결과 적당한 Courant 수의 증가는 계산 정확도의 감소 없이 용탕 계산 속도를 향상시킬 수 있는 것으로 나타났다. 또한 만족할 만한 계산 정확도와 효율이 이 알고리즘의 실제 제품 해석을 통해 얻어졌다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.10a
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• pp.178-180
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• 2022

An application implementation that allows users to train yoga posture based on the landmark of yoga posture of yoga instructors obtained from the Google Firebase ML Kit was introduced. Using the ML Kit, the user's posture is classified and landmarks corresponding to each joint are obtained. The accuracy measurement reference value for the yoga posture is set through the angle formed by the joints of the obtained landmark. The accuracy between the reference landmark for the yoga posture of professional yoga instructors and the landmark for the user's pose through the ML Kit was compared. According to the accuracy reference value, information on malfunction and correct motion is provided to the user through Text-to-Speech (TTS). Users are managed effectively with Firebase, and a system that displays the amount of exercise through a counter and timer when the user performs an exercise that meets the accuracy reference value was explained.