• The Journal of the Korea Contents Association
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• v.15 no.5
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• pp.18-26
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• 2015

In this paper, we presented a design and control method of multi-stage with wagon and lift stage. Multi-stage system has 4 degree-of-freedom(DOF), i.e., forward/backward/left/right/rotate and up/down motion. Wagon mechanism in the type of two wheel and steering is proposed in order to improve for the maneuverability compared to the existing differential-type wagons. Also, the lift mechanism is designed by interlocking type in order to make the maximum height bigger than 10 times of the original height. We also proposed a path planning algorithm. The performance of the propped system is validated via multi motion experiments, so that the multi-stage system is useful for various performances production.

• Journal of the Institute of Convergence Signal Processing
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• v.21 no.1
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• pp.21-28
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• 2020

In this paper, a new type of electric wheelbarrow is proposed and developed. The developed electric wheelbarrow is equipped with an attitude reference system(ARS) sensor, which consists of 3-axis acceleration sensor and 2-axis Gyro sensor so that it can estimate pitch angle and roll angle. When an operator tilts the wheelbarrow up and down, the pitch angle is detected. The sign of the pitch angle is interpreted as the operator's intention for moving the wheelbarrow forward or backward and the controller drives the wheel of the wheelbarrow with the velocity according to the magnitude of the detected pitch angle. A cargo box of the wheelbarrow is designed to rotate and is controlled to maintain level always, so an operator can handle the electric wheelbarrow easily and safely. The wheelbarrow consists of an in-wheel motor, a DC motor, motor drives, an ARS sensor considering economical use in industrial field. Three experiments are performed to verify the feasibility and stability of the electric wheelbarrow.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.7
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• pp.275-282
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• 2018

Mountain trams are an environmental-friendly transportation system that run wirelessly on an embedded track constructed on previous mountain roads, and can run despite the frozen road. On the other hand, there is some difficulty on sharp and steep tracks. In this study, after possible technical problems were defined in mountain trams running on a sharp and steep track, the design solutions for the interface structure of bogie and carbody were proposed. In addition, a prototype was made and its performance was tested to verify the solutions. Because the difference in the distance of the inner and outer rails on a sharp curve is severe enough to interrupt running, independent rotating wheels with different angular speeds were developed and applied. To prevent derailment due to the large attack angle and lateral force caused by the previous vehicle of 2bogie-and-1carbody on the sharp curve, a vehicle with 1bogie-and-1carbody was designed and applied. A prototype vehicle of 1bogie-and-1carbody with independent rotating wheels was made to improve the performance during the test running on a small track. A coupler was designed to absorb the large rotations of 3 degrees-of-freedom between the carbodies of a mountain tram running on the steep curved track. After a small scale prototype was made, the performance was verified by a function test.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.40 no.1
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• pp.78-85
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• 2004

The new biotelemetry method and system that the installation and the treatment of equipment is convenient and the instantaneously detailed position of the fish attached a pinger is able to track comparatively easily had been developed, an practicality of it were verified in the water tank and the small sea port through the tracking of fish. The biotelemetry method had been gotten the three dimensional locations of fish to the receiving transducer by combining of the super short base line (SSBL) method to detect the direction of pinger and the pinger synchronizing method to measure the range from receiving transducer to pinger. The receiving system had been designed to realize the high precision or wide detection range by application of the basic design method for receiving system of biotelemetry and the hydrophone array configuration. From tracking test of carp in the water tank, the migration course and the velocity of carp was investigated and the observed migration course was compared with measurement. The measured migration course of carp coincided with the observation in the main and the position of carp was able to track three dimensionally. The velocity of carp measured by the moving average method was 11.2cm/s. From tracking test of yellowtail in the small sea port, the migration course and the velocity of yellowtail was investigated at natural condition. The position of yellowtail was able to track three dimensionally and the velocity of it measured by moving average method was 43.9cm/s.

• Korean Journal of Applied Biomechanics
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• v.19 no.1
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• pp.67-75
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• 2009

The purpose of this study is to analyze the effects of target position on the bowling motion. Four female high school athletes with more than four years of bowling experiences were recruited to this study. The major results of this study are as follows; When a subject treats the 1st pin, The spin angle of a coxa for the target position is largely kept from the downswing to the backswing peak point. When a subject treats the 7th pin, As the 7th pin exists at the left side for the right shoulder axis of the thrower, the movement of the ball center of the thrower from side to side is the lowest. In addition, the time required and horizontal speed appear the highest in the release section. The slant angle of a shoulder is largely increased as she moves from the backswing peak point to the release section. The twist angle of a shoulder also appears small as a throw motion is made toward the left side. When a subject treats the 10th pin, The spin angle of a shoulder and the twist angle of a body in motion appear the largest in the release section. So, there are the effects of target position on the bowling motion.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.1789-1793
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• 2008

전자파표면유속계는 홍수유속측정을 위하여 개발된 기기로 평 갈수기에는 유속측정이 불가하여 프로펠러 유속계를 이용하고 있다. 현재 보급된 전자파표면유속계는 하천의 흐름방향에 나란하게 설치하였을 때에만 유속을 측정할 수 있는 기기의 구조상의 한계성 때문에 교량이 없는 지점에서는 유속측정이 불가하여 유량산정을 할 수가 없다. 또한 편각측정이 불가능하여 기기를 각 측선마다 이동 설치하여야 하기 때문에 유속측정시 효율성 떨어진다. 이에 홍수시 유량측정의 효율성을 증대시키고 전자파표면유속계의 활용도를 높이고자 편각측정이 가능하도록 전자파표면유속계의 성능을 개선하는 것이 본 연구의 주된 목적이다. 전자파표면 유속계에서의 편각 측정은 하천의 유속방향을 기준으로 정면에서 측정하면 수평 편각이 0도가 되며 좌우로 안테나를 회전하여 움직인 각도가 측정 편각으로 결정된다. 현장에서 전자파표면유속계의 사용시 편의성을 높이고 유량측정을 효율적으로 하기 위해서는 가급적 편각을 크게 해서 측정을 해야 하지만, 편각이 증가하면 전자파의 물리적 특성 때문에 반사된 신호의 수신 크기가 감소하여 측정이 불가능하게 된다. 이러한 문제를 해결하기 위해서는 유속 측정시 전자파 출력을 기존의 시스템보다 높게 물표면에 발사하여야 하며 안테나를 포함한 RF 모듈의 수신감도 및 지향성이 개선되어야 한다. 이에 편각측정이 가능하도록 이러한 사항에 주안점을 두어 새로운 시스템을 구성하였다. 수신감도 향상을 위해서는 물표면에 반사되어 돌아오는 신호를 가장 먼저 수신하는 안테나의 특성이 중요하며 그 다음 수신용 증폭기, IF 증폭기 순으로 개선이 필요하다. 본 연구에서는 안테나의 형태를 기존 파라볼릭 안테나에서 위상 배열 평면안테나로 변경하였으며, 이에 따른 이점으로는 송수신부를 분리하여 하나의 평면에 두 개의 안테나를 구성할 수 있다는 사항이다. 즉 외형적으로는 하나의 안테나로 보이지만 두 개의 안테나가 하나로 구성된 것이다. 송수신부를 분리하는 형태는 기존 파라볼릭 안테나에선 불가능한 구조로 변경에 따른 수신감도 향상은 수치적으로 10dB 이상 개선하였다. 송수신부 분리가 수신감도에 영향을 미치는 이유는 물표면으로 발사된 송신 신호의 일부가 수신단으로 유입되는 현상으로 누설되는 송신 신호를 최대한 차단하는 분리도가 수신 신호 검출에 직접적인 양향을 주기 때문에다. 평면 안테나를 적용하면 기존 파라볼릭 안테나에서 사용하던 써큘레이터라는 부품을 삭제할 수 있으며, 안테나의 구조적인 분리를 통해서 수신감도를 개선할 수 있었다. 안테나의 지향성은 발사하는 전자파의 빔폭 성능과 일치하며 각도 단위로 표시한다. 각도 값이 작을수록 전자파의 에너지가 한 곳에 집중된다고 말할 수 있다. 즉 빔폭이 크면 측정시 반사면적이 커져 정확한 지점의 유속을 측정하기 어려운 문제가 발생한다. 본 연구를 통해 빔폭은 기존 안테나 대비2도를 개선하였으며 25%의 개선 효과를 얻었다. 또한 수신감도 및 지향성 개선과 더불어 전자파의 출력을 기존 장비 대비하여 1.6배를 증가하여 편각측정을 위한 전자파표면 유속계의 성능을 개선하였다.

• Journal of the Korea Society of Computer and Information
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• v.24 no.12
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• pp.25-33
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• 2019

This paper presents a novel evolutionary framework for optimizing a bio-inspired fully dynamic neurocontroller for the maneuverable flapping flight of a simulated bird-sized ornithopter robot which takes advantage of the morphological computation and mechansensory feedback to improve flight stability. In order to cope with the difficulty of generating robust flapping flight and its maneuver, the wing of robot is modelled as a series of sub-plates joined by passive torsional springs, which implements the simplified version of feathers attached to the forearm skeleton. The neural controller is designed to have a bilaterally symmetric structure which consists of two fully connected neural network modules receiving mirrored sensory inputs from a series of flight navigation sensors as well as feather mechanosensors to let them participate in pattern generation. The synergy of wing compliance and its sensory reflexes gives a possibility that the robot can feel and exploit aerodynamic forces on its wings to potentially contribute to the agility and stability during flight. The evolved robot exhibited target-following flight maneuver using asymmetric wing movements as well as its tail, showing robustness to external aerodynamic disturbances.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.5B
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• pp.469-479
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• 2006

In order to investigate characteristics of the primary flow and the secondary currents in meandering channels, the laboratory experiments were conducted in S-curved channels with angle of bend, $150^{\circ}$, and sinuosity of 1.52. The experimental conditions was decided varying average depth and velocity. Under these experimental conditions, spatial variations of the secondary currents in multiple bends were observed. The experimental results revealed that the distribution of primary flow in straight section is symmetric without respect to the experimental condition and the maximum velocity line of the primary flow occurs along the shortest path in experimental channel, supporting the result of previous works. The secondary currents in second bend became more developed than those in first bend. Particularly, the outer bank cell developed distinctively and the secondary current intensity was low at the straight section and high at the bends, periodically. Also, the secondary current intensity at the bends was as twice to three times as that at the straight section, and has its maximum value at the second bend. The turbulent flow characteristics of meandering channel was investigated with turbulent intensity of the primary flow and Reynolds shear stress. It was observed that the turbulent intensity is increasing when the velocity deviation of the primary flow is large whereas Reynolds shear stress increases when both the velocity deviation of the primary flow and the secondary current are large.

• Progress in Medical Physics
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• v.22 no.2
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• pp.72-78
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• 2011

The aim of this study is to evaluate the patient's setup errors in TomoTherapy (Hi-Art II, TomoTherapy, USA) Bodyfix system (Medical Intelligence, Ele-kta, Schwabmuchen, Germany) pressure in the vacuum compression, depending on and were evaluated. Bodyfix immobilization system and vacuum pressure was compression applied to the patients who received Tomotherapy thoracic and abdominal area, 21 patients were selected and TomoTehpay treatment total 477 of MVCT images were obtained. The translational (medial-lateral: ML, anterior-posterior: AP, superior-inferior: SI directions) and rolling were recorded and analyzed statistically. Using Pearson's product-moment coefficient and One-way ANOVA, the degree of correlation depending on the different vacuum pressure levels were statistically analyzed for setup errors from five groups (p<0.05). The largest average and standard deviation of systematic errors were 6.00, 5.95 mm in the AP and SI directions, respectively. The largest average of random errors were 4.72 mm in the SI directions. The correlation coefficients were 0.485, 0.244, and 0.637 for the ML-Roll, AP-Vector, and SI-Vector, respectively. SI-Vector direction showed the best relationship. In the results of the different degree of vacuum pressure in five groups (Pressure range: 30~70 mbar), the setup errors between the ML, SI in both directions and Roll p=0.00 (p<0.05) were shown significant differences. The average errors of SI direction in the vacuum pressure of 40 mbar and 70 mbar group were 4.78 mm and -0.74 mm, respectively. In this study, the correlation between the vacuum pressure and the setup-errors were statistically analyzed. The fact that setup-errors in SI direction is dependent in vacuum pressure considerly setup-errors and movement of interal organs was identified. Finally, setup-errors, and it, based on the movement of internal organs in Bodyfix system we should apply more than 50 mbar vacuum pressure. Based on the results of this study, it is suggested that accuracy of the vacuum pressure and the quantitative analysis of movement of internal organs and the tumor should be studied.

• Journal of Astronomy and Space Sciences
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• v.25 no.4
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• pp.405-414
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• 2008

To better understand the physical processes that control the high-latitude lower thermospheric dynamics, we analyze the divergence and vorticity of the high-latitude neutral wind field in the lower thermosphere during the southern summertime for different IMF conditions. For this study the National Center for Atmospheric Research Thermosphere-Ionosphere Electrodynamics General Circulation Model (NCAR-TIEG CM) is used. The analysis of the large-scale vorticity and divergence provides basic understanding flow configurations to help elucidate the momentum sources that ulti-mately determine the total wind field in the lower polar thermosphere and provides insight into the relative strengths of the different sources of momentum responsible for driving winds. The mean neutral wind pattern in the high-latitude lower thermosphere is dominated by rotational flow, imparted primarily through the ion drag force, rather than by divergent flow, imparted primarily through Joule and solar heating. The difference vorticity, obtained by subtracting values with zero IMF from those with non-zero IMF, in the high-latitude lower thermosphere is much larger than the difference divergence for all IMF conditions, indicating that a larger response of the thermospheric wind system to enhancement in the momentum input generating the rotational motion with elevated IMF than the corresponding energy input generating the divergent motion. the difference vorticity in the high-latitude lower thermosphere depends on the direction of the IMF. The difference vorticity for negative and positive $B_y$ shows positive and negative, respectively, at higher magnetic latitudes than $-70^{\circ}$. For negative $B_z$, the difference vorticities have positive in the dusk sector and negative in the dawn sector. The difference vorticities for positive $B_z$ have opposite sign. Negative IMF $B_z$ has a stronger effect on the vorticity than does positive $B_z$.