• Journal of the korean Society of Automotive Engineers
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• v.9 no.1
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• pp.3-8
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• 1987

자연과학은 계측기술의 발전과 함께 진전하고 있다고 보아도 된다. 여러 가지 자연현상을 정상 적이 아닌 정량적으로 엄밀하고도 정확하게 잡아냄으로서 비로소 한 사물과 다른 사물과의 관련 성과 인과관계를 적절하고도 확실하게 이해할 수가 있다. 최근 전자공학의 발달로 어제의 정밀 계측기와 오늘의 정밀계측기의 성능이나 면모가 일신되어 그 변화발전의 속도가 다른 분야보다 훨씬 앞지르고 있다고 해도 과언이 아니다. 특히 사물을 정상적으로 인식하는 패턴(pattern)과 같은 인식기술 또한 첨단계측기술이라 하겠으나, 이는 목적에 따라서는 일반적으로 불충분하며 수치로써 표현됨으로써 비로서 보편적이고도 타탕성이 있다고 보게되며, 적합하고도 확실한 정 보를 입수하며 지식을 잘 다듬음으로써 비로서 다른 사물에 잘 응용할 수가 있는 것이다. 여러 가지 공업적인 기술에 있어서 이 계측은 모든 것의 기초가 되며 계측기의 발달은 바로 그 분야의 문제해결과 적결되어서, 그 분야의 학문과 기술을 보다 한발 전진시켜주는 요인이 된다고 보아서 앞으로의 정밀계측기의 개발연구는 더울 중요성이 높게 평가되야만 한다고 생각한다. 따라서 자동차공업은 하나의 종합된 정밀기계공업이라고 볼 수 있으며 매년 우리나라 자동차생산은 증 대일락에 있고 그 수출량 또한 증가되어 품질보증은 그 어느때보다도 요구되고 있어, 과학의 기초인 계측에 관해 기초개명에서부터 최근의 정밀계측시스템에 대해서 살펴보고자 한다.

• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.415-416
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• 2014

FCEV(Fuel Cell Electric Vehicle)는 연료전지를 사용하여 차량 구동용 전동기에 필요한 에너지를 공급한다. 연료전지는 부하에 급격한 변화가 발생하였을 시에 과도특성이 나타나고 자동차에 에너지를 공급하는 속도에 영향을 준다. 그러므로 연료전지의 특성상 FCEV에서 배터리는 연료전지와 함께 사용된다. FCEV 및 전기자동차는 배터리의 대용량화를 위해 일반적으로 배터리 셀을 직/병렬로 모듈화하여 사용하는데, 이때 배터리 모듈의 충전 및 방전이 반복될 경우, 각 배터리 잔존용량의 불균형이 나타난다. 본 논문은 연료전지 전기자동차용 전력변환 장치를 이용하여 배터리 셀을 모듈화하여 모듈 별 밸런싱을 수행하는 시스템의 설계와 제어기법을 제안한다. 각각의 배터리 모듈과 연료전지를 연결하는 컨버터 모듈은 독립적으로 제어되어 배터리를 모듈 단위로 균등화시킨다. 이때 연료전지를 입력으로 절연형 컨버터를 병렬로 사용하며, 각각의 배터리 모듈을 균일하게 충전한다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2019.07a
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• pp.441-442
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• 2019

본 논문에서는 VR(Virtual Reality)라는 가상 현실 시스템 개발 툴인 Unreal Engine4을 사용하여 블루 프린트(Blue Print)로 야구 배팅 게임과 장애물 격파 피칭 게임을 개발하였다. 배팅 게임은 가상의 투수로부터 공 속도와 공이 랜덤하게 자동으로 투구된다. 이 때 사용자가 게임 콘트롤러(Controller)로 가상 배트를 이용하여 공을 타격하면 점수를 획득하는 게임이다. 장애물 격파 피칭 게임은 사용자가 게임 콘트롤러에 그립버튼을 눌러 데미지가 다른 공이 랜덤하게 바로 앞에 생성하여 이 공을 콘트롤러로 잡아서 장애물에 던져 격파하면 점수를 획득하는 게임이다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2020.07a
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• pp.69-70
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• 2020

본 논문에서는 현재 운영되고 있는 온라인 게임에서 실력을 겨루는 형태의 경쟁적인 온라인 게임들에서 사용되어지고 있는 게임 핵이 게임에 미치는 영향을 제시한다. 그리고 게임 핵을 검출하기 위한 객체 인식 기술로 실시간 정보 획득이 가능한 YOLOv3 알고리즘을 사용하였다. 이는 속도가 빠른 객체인식 기술이며 이미지 속 물체의 외관 뿐만 아니라 전체적인 컨텍스트까지 학습을 진행한다. 그리고 나아가 게임 핵 검출을 위한 개발 및 운영적 측면에서 어떻게 지원돼야 하는 등의 내용을 제시한다.

• Korean Journal of Agricultural Science
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• v.13 no.1
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• pp.103-112
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• 1986

This study was carried out to prevent the entwining of rice straw on rotary shaft and blade where rice straw was spreaded on paddy field as an organic source before rotary tilling. The rotary tillage was conducted in the paddy field having the soil moisture contents of 30%, 39%, 59% in dry basis and spreaded rice straw (450kg/10a) of 30cm, 45cm, 90cm length with the edged curve angles of rotary blade of $30^{\circ}$, $40^{\circ}$, $50^{\circ}$, $55^{\circ}$ at Yuseung area. And the test were performed on the plot which has width of 30cm and 5cm length and the quantity of entwined rice straw was analized. The test results were summarized as the followings. 1. Entwining phenomenon of rice straw was decreased as the blade edged curve angle increased. The edged curve angle of rotary blade must be determind by considering the characteristics of soil cutting resistance, tilling torque and entwining phenomenon of rice straw. But according to the entwining phenomenon of rice straw only, the edged curve angle of rotary blade should be bigger than $55^{\circ}$ for design. 2. Amount of entwining rice straw was minimized when soil moisture contents was 30 percent (d. b.). It would be better that rotary tillage is performed when soil moisture contents is lower than 30 percent in dry basis. 3. Amount of entwining rice straw was minimized when the length of rice straw was 30cm with $55^{\circ}$ edged curve angle. Therefore, it would be better to chop rice straw as 30cm. 4. Entwining phenomenon of rice straw was decreased as the forward speed decreased. To decrease the entwining rice straw, rotary tillage should be done with forward fist gear (0.35m/s).

• Journal of the Society of Naval Architects of Korea
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• v.33 no.2
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• pp.127-138
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• 1996

The strip method, unified theory and 3-D panel method are commonly used methods for the seakeeping analysis of high-speed vessels. The strip method which is basically 2-dimensional method is known to give incorrect hydrodynamic coefficients and motion responses for the cases of high speed and low frequency region. And the unified theory which uses two dimensional approach in inner domain and slender body theory in outer domain is very complicate in computational modelling. Though the 3-D panel method requires comparatively long computation time, it is believed that the method gives good results without any limitation in ship speed and range of frequency for computation. In the 3-D panel method the source singularity representing translating and pulsating Green function is used and Hoff's method is adopted for the numerical calculation of the Green function. The computation time can be reduced by using the symmetry relationship with respect to longitudinal axis. In this paper the strip method and the 3-D panel method are compared for the seakeeping analysis of a high-speed catamaran. The Compared items are the hydrodynamic coefficients, wave exciting forces, frequency response functions and short-term responses in irregular waves.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.4
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• pp.1777-1783
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• 2012

In this paper, a new motor driving circuit is designed to improve the output performance of DC motor, and a controller is developed with the designed circuit. By the designed driving circuit, a controller can continuously drive DC motors by a transformer which has switching signals of a self-generated circuit to operate it. And while the DC motor have a maximum velocity, the reference voltage can be maintained higher value than that of triangle voltage and it makes the DC motor driving transistor ON and maximum power. A 24V-500W DC motor controller is developed with the proposed motor driving circuit, and also a small electric car is made and the driving test of it is executed. The test results shows that it can continuously control go and back speed of motor with 12A driving current. And also, it is verified that the over current and heat detecting function is operating correctly and the rest value of the used battery can be displayed as 6 step from 20 to 100%.

• Geotechnical Engineering
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• v.14 no.2
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• pp.67-78
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• 1998

Microtunnelling is a technique applied to install a small-size tunnel in a soft cohesionless ground. In microtunnelling, a series of concrete tubular segments are pushed from a starting pit to power-line tunnel under a runway of JFK international airport at New York. During the microtunneling process, bentonite is jetted with very hyh pressure through a nozzle to advance disturbance in the subgrade caused by the pressurized bentonite in the aspects of subgrade stiffness. SASW measurements were performed on the runway above the center line of the shear wave velocity profiles. Besides the change of subgrade stiffness, the change of subgrade strength was also evaluated by the site-specific relationships between shear wave velocity and N value, which was determined by N values. The estimated N values gave a clue to the understanding of the change of subgrade strength.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.1B
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• pp.15-25
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• 2006

Using kinematic wave equation, the influence of moving storms to runoff was analysised with a focus on watersheds. Watershed shapes used are the oblong, square and elongated shape, and the distribution types of moving storms used are uniform, advanced and intermediate type. The runoff hydrographs according to the rainfall distribution types were simulated and the characteristics were explored for the storms moving down, up and cross the watershed with various velocity. The shape, peak time and peak runoff of a runoff hydrograph are significantly influenced by spatial and temporal variability in rainfall and watershed shapes. A rain storm moving in the cross direction of channel flow produces a higher peak runoff than in the downstream direction and upstream direction. A peak runoff from a storm moving downstream exceeds that from a storm moving upstream. For storms moving downstream peak time was more delayed than for other storm direction in the case of elongated watershed. The runoff volume and time base of the hydrograph decreased with the increasing storm speed.

• Journal of the Society of Naval Architects of Korea
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• v.33 no.3
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• pp.35-47
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• 1996

A surface panel method treating a boundary-value problem of the Dirichlet type is presented to design a three dimensional body with free surface corresponding to a prescribed pressure distribution. An integral equation is derived from Green's theorem, giving a relation between total potential of known strength and the unknown local flux. Upon discretization, a system of linear simultaneous equations is formed including free surface boundary condition and is solved for an assumed geometry. The pseudo local flux, present due to the incorrect positioning of the assumed geometry, plays a role f the geometry corrector, with which the new geometry is computed for the next iteration. Sample designs for submerged spheroids and Wigley hull and carried out to demonstrate the stable convergence, the effectiveness and the robustness of the method. For the calculation of the wave resistance, normal dipoles and Rankine sources are distributed on the body surface and Rankine sources on the free surface. The free surface boundary condition is linearized with respect to the oncoming flow. Four-points upwind finite difference scheme is used to compute the free surface boundary condition. A hyperboloidal panel is adopted to represent the hull surface, which can compensate the defects of the low-order panel method. The design of a 5500TEU container carrier is performed with respect to reduction of the wave resistance. To reduce the wave resistance, calculated pressure on the hull surface is modified to have the lower fluctuation, and is applied as a Dirichlet type dynamic boundary condition on the hull surface. The designed hull form is verified to have the lower wave resistance than the initial one not only by computation but by experiment.