• 지질공학
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• 제25권4호
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• pp.485-498
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• 2015

울산광역시 매곡동 일대에서 새롭게 발견된 단층대의 기하학적, 운동학적 특성 및 제4기 단층운동에 대해 알아보고자 야외조사를 통한 지질구조분석을 실시하였다. 그 결과, 퇴적암이 분포하는 첫 번째 조사지점에서는 100 m 내외의 절취사면을 따라 반복층서, 소규모 단층, 단열대, 변형띠대 등이 연속적으로 관찰되고 있어, 이 지점은 대규모 단층의 손상대에 속하는 것으로 해석된다. 한편 주로 화강암 암편으로 구성된 쇄설성 퇴적층이 분포하는 두 번째 조사지점에서는 저각의 경사를 보이는 여러 조의 단층이 서로 분지 또는 결합하는 형태로 발달하고 있어 대규모 역단층이 발달하는 것으로 판단된다. 이 단층의 단층비지 내에 포함된 유기물의 방사성탄소연대에 기초해 추론된 단층의 최후기 운동시기는 33,275 ± 355년 전 이후로 제한된다. 이번 조사에서 확인된 단층대의 손상대 규모, 운동감각, 운동시기 등은 이 단층대가 연구지역 인근의 대규모 신기단층으로 알려진 울산단층 또는 연일구조선과 밀접한 관련이 있음을 시사한다. 따라서 연구지역 일대에 조성 중인 산업단지와 아파트를 비롯한 여러 시설물에 대한 지진 및 지질학적 안정성을 확보하고 이 지역에서의 지질재해에 대비하기 위해서는 보다 정밀한 구조지질학 및 고지진학 관점에서 이 단층에 대한 연구가 필요할 것으로 판단된다.

• 한국농공학회지
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• 제30권3호
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• pp.58-68
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• 1988

Most of the Korean watersheds are mountaineous and consist of various soil types and land uses And seldom watersheds are found to have long term hydrologic records. The SNUA, a hydrologic watershed model was developed to meet the unique characteristics of Korean watershed and simulate the storm hydrographs from a small mountaineous watershed. Also the applicability of the model was tested by comparing the simulated storm hydrographs and the observed from Dochuk watershed, Gwangjugun, Kyunggido The conclusions obtained in this study could be summarized as follows ; 1. The model includes the simulation of interception, evaporation and infiltration for land surface hydrologic cycle on the single storm basis and the flow routing features for both overland and channel systems. 2. Net rainfall is estimated from the continuous computation of water balance at the surface of interception storage accounting for the rainfall intensities and the evaporation losses at each time step. 3. Excess rainfall is calculated by the abstraction of infiltration loss estimated by the Green and Ainpt Model from the net rainfall. 4. A momentum equation in the form of kinematic wave representation is solved by the finite differential method to obtain the runoff rate at the exit of the watershed. 5. The developed SNUA Model is a type of distributed and event model that considers the spatial distribution of the watershed parameters and simulates the hydrograph on a single storm basis. 6. The results of verification test show that the simulated peak flows agree with the observed in the occurence time but have relative enors in the range of 5.4-40.6% in various flow rates and also show that the simulated total runoff have 6.9-32% of relative errors against the observed. 7. To improve the applicability of the model, it was thought that more studies like the application test to the other watersheds of various types or the addition of the other hydrologk components describing subsurface storages are needed.

• 한국운동역학회지
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• 제21권4호
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• pp.495-501
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• 2011

The purpose of this study was to develop the inertial sensor module system to detect gait event using single angular rate sensor(gyroscope), and evaluate the accuracy of this system. This sensor module is attached at the heel and gait events such as heel strike, foot flat, heel off, toe off are detected by using proposed automatic event detection algorithm. The developed algorithm detect characteristics of pitch data of the gyroscope to find gait event. To evaluate the accuracy of system, 3D motion capture system was used and synchronized with sensor module system for comparison of gait event timings. In experiment, 6 subjects performed 5 trials level walking with 3 different conditions such as slow, preferred and fast. Results showed that gait event timings by sensor module system are similar to that by kinematic data, because maximum absolute errors were under 37.4msec regardless of gait velocity. Therefore, this system can be used to detect gait events. Although this system has advantages of small, light weight, long-term monitoring and high accuracy, it is necessary to improve the system to get other gait information such as gait velocity, stride length, step width and joint angles.

• 대한기계학회논문집A
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• 제37권8호
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• pp.1043-1050
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• 2013

병렬로봇은 구조적 특성 때문에 정밀성 및 고강성이 요구되는 분야와 고속성이 요구되는 분야에서 주로 적용되고 있다. 물류 분야에서 고속이송의 중요성은 날이 갈수록 증가하고 있으며, 본 연구에서도 동일한 목적으로 고속 이송에 적용될 병렬로봇이 개발되었다. 개발된 로봇은 최대 3kg의 부하를 이송할 수 있으며 0.1kg의 부하조건에서의 최대 운전 조건은 싸이클 타임 0.3sec로 최대 속도 약 4.5m/sec로 운전할 수 있으며(Pick & Place 작업, Adept cycle) 이때 최대 가속도는 약 13G에 달한다. 본 논문에서는 개발된 고속 병렬로봇의 설계 및 해석에 관한 연구결과와 개발된 로봇의 성능에 관해 소개하고자 한다.

• 한국수자원학회논문집
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• 제45권4호
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• pp.349-360
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• 2012

본 연구에서는 3차원 점성 흐름에 적용될 수 있는 비정수압 자유수면 모형을 수평방향 직교 곡선좌표계에서 개발하였다. 개발된 수치모형은 엇갈린 격자를 사용함으로써 발생되는 자유수면에서의 경계조건 종결 문제를 수면층 방정식을 도입하여 해결하였으며, 난류의 유동 해석을 위한 폐합식으로 등방성의 k-${\varepsilon}$ 난류모형을 이용하였다. 본 연구에서 운동량방정식은 이송-확산항만으로 중간단계의 유속을 예측하고, 압력 및 중력을 포함하는 생성항과 연속방정식을 결합하여 다음 시간단계의 유동장을 결정하는 계산 단계 분리법을 이용하였다. 수치모형의 적용성 평가를 위하여 폐쇄된 2차원 수조에서의 취송류, 급경사를 가지는 2차원 수로에서의 흐름, 원심력에 의한 이차류 흐름특성 분석을 위한 3차원 급변 만곡류에 대한 모의를 실시하였다. 수치모의 예측치는 수리모형 실험값과 수위, 유속, 난류특성 등에서 일치하는 양상을 보이는 것이 확인되었다.

• 대한인간공학회지
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• 제31권2호
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• pp.345-352
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• 2012

Objective: The aim of this study is to evaluate the accuracy and reliability of Spine-Pelvis Monitor(SPM) that was developed to measure 3-dimensional motion of spine and pelvis using tilt sensor and gyro sensor. Background: The main cause of low back pain is very much associated with the task using the low back and pelvis, but no measurement technique can quantify the both spine and pelvis. Method: For testing the SPM, 125 angles from three anatomical planes were measured three times in order to evaluate the accuracy and reliability. The accuracy of SPM in measuring dynamic motion was evaluated using digital motion analysis system. The motion pattern captured by two measuring methods was compared with each other. In result, the percentage error and Cronbach coefficient alpha were calculated to evaluate the accuracy and reliability. Results: The percentage error was 0.35% in flexion-extension on sagittal plane, 0.43% in lateral bending on coronal plane, and 0.40% in twisting on transverse plane. The Cronbach coefficient alpha was 1.00, 0.99 and 0.99 in sagittal, coronal and transvers plane, respectively. Conclusion: The SPM showed less than 1% error for static measurement, and showed reasonably similar pattern with the digital motion system. Application: The results of this study showed that the SPM can be the measuring method of spine pelvis motion that enhances the kinematic analysis of low back dynamics.

• 제어로봇시스템학회논문지
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• 제17권1호
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• pp.31-37
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• 2011

Recently gantry-type robot with 3 axes rectangular coordinates have been studied in the many industrial production equipment and machinery fields. To acquire a good handling and motion performance of this robot, reducing the settling-time and securing the accurate-transfer positioning under high-speed conditions should be required. However when robot is moved in high-speed, the large inertia of robot can lead to serious vibration of robot's head. The time-delayed control characteristics of this robot can also lead to tracking error. In this research, the analysis of the effects of higher order positional-profile is carried out to assure high-speed performance and stiffness specifications. To remove the residual vibration caused by kinematic coupling effect of dual-servo gantry, we develop a dual-servo gantry of rotary type that moving frame of x-axis rotates about z-axis. In order to decrease the tracking error, the 3 type lead-filter through system identification was applied respectively. From the experimental results, it was shown that zero-order series leader-filter has the best performance about tracking error and settling time.

• 한국해양공학회지
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• 제28권5호
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• pp.466-473
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• 2014

Underwater gliders do not have any external propulsion systems that can generate and control their motion. Generally, underwater gliders would obtain a propulsive force through the lift force generated on the body by a fluid. Underwater gliders should be equipped with mechanisms that can induce heave and pitch motions. In this study, an inner movable and rotatable mass mechanism was proposed to generate the pitch and roll motions of an underwater glider. In addition, a buoyancy control unit was presented to adjust the displacement of the underwater glider. The buoyancy control unit could generate the heave motion of the underwater glider. In order to analyze the underwater dynamic behavior of this system, nonlinear 6-DOF dynamic equations that included mathematical models of the inner movable mass and buoyancy control unit were derived. Only kinematic characteristics such as the location of the inner movable mass and the piston position of the buoyancy control unit were considered because the velocities of these systems are very slow. The effectiveness of the proposed dynamic modeling was verified through sawtooth and spiraling motion simulations.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.415.2-415.2
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• 2016

Triboelectric nanogenerator (TENG) is one of ways to convert mechanical energy sound, waves, wind, vibrations, and human motions to available electrical energy. The principal mechanism to generate electrical energy is based on contact electrification on material surface and electrostatic induction between electrodes. The performance of TENG are dependent on amount of the input mechanical energy and characteristics of triboelectric materials. Furthermore, the whole TENG system including mechanical structure and electrical system can effect on output performance of TENG. In this work, we investigated the effect of gear train on output performance and power conversion efficiency (PCE) of TENG under a given input energy. We applied the gear train on mechanical structure to improve the contact rate. We measured the output energy under a constant input energy by controlling the size of the working gear. We prepared gears with gear ratios (rin/rw) of 1, 1.7, and 5. Under the constant input energy, the voltage and current from our gear-based TENG system were enhanced up to the maximum of 3.6 times and 4.4 times, respectively. Also, the PCE was increased up to 7 times at input frequency of 1.5 Hz. In order to understand the effect of kinematic design on TENG system, we performed a capacitor experiment with rectification circuit that provide DC voltage and current. Under the input frequency of 4.5 Hz, we obtained a 3 times enhanced rectifying voltage at a gear ratio of 5. The measured capacitor voltage was enhanced up to about 8 fold in using our TENG system. It is attributed that our gear-based TENG system could improve simultaneously the magnitude as well as the generation time of output power, finally enhancing output energy. Therefore, our gear-based TENG system provided an effective way to enhance the PCE of TENGs operating at a given input energy.

• 한국운동역학회지
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• 제18권1호
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• pp.11-19
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• 2008

전국 규모의 경기에서 우승한 선수들을 포함한 남자대학 선수 8명을 대상으로 했다. 피험자의 4명은 펜홀더 그립, 4명은 세이크핸드 그립의 라켓을 사용하며 모두 오른손을 사용했다. 탁구의 포핸드 드라이브와 스매시의 라켓스윙동작과 관련된 각도성분, 스윙궤도, 스윙자세 등의 3차원 각운동 특성을 비교 분석한 결과 다음과 같은 결론을 얻었다. 라켓각(p<.05)과 라켓의 스윙각(p<.01)에서 두 동작 간 유의한 차이를 보였다. 스매시는 백스윙 자세에서 이미 라켓을 세워 라켓각을 크게 유지했으며, 라켓의 스윙각을 작게 해서 볼 스피드에 비중을 두는 것을 알 수 있었다. 또한 백스윙 자세에서 라켓헤드의 높이도 두 동작 간 큰 차이가 나타났다. 임팩트 순간 phg에서 두 동작 간 라켓 장축의 열림각의 차이가 크게 나타난 것을 보면, 볼에 순회전의 스핀을 넣기 위해서 약간 뒤에서 임팩트가 이루어진 것을 알 수 있었다. 백스윙 자세에서 상체의 기울기는 드라이브 동작에서 phg보다 shg에서 상체를 조금 더 구부리는 것은 중립 자세에서 라켓 그립의 구조적 차이로 인한 것으로 판단된다.