• 에너지공학
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• 제13권3호
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• pp.214-218
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• 2004

본 연구에서는 용량가변방식을 적용한 PWM 압축기의 냉방운전 시 소비전력 변화 및 성능향상을 조사하기 위해서 기존 및 개선된 압축기의 능력, 소비전력, COP를 측정하여 비교하였다. 압축기의 효율 향상을 위해 무부하 상태에서 압축기 운전콘덴서의 변경, 복수구동부의 교차운전, 그리고 주 전류단에 코일를 적용하여 소비전력의 변화를 측정하였다. 용량가변형인 PWM압축기는 압축기 능력이 증가함에 따라 소비전력과 COP가 선형적으로 증가하였다. 압축기의 운전 콘덴서를 바꾸어가면서 소비전력을 측정한 경우 소비전력의 최적점이 확인되었다. 한편, 복수 구동부의 적용으로 불필요한 과전압에 의한 소비전력을 감소할 수 있었다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2012년도 춘계학술대회 논문집
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• pp.369-370
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• 2012

• 대한인간공학회지
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• 제31권5호
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• pp.629-636
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• 2012

Objective: The purpose of this study is to compare the characteristics of single and double finger gestures related on the web browser and to extract the appropriate finger gestures. Background: As electronic equipment emphasizes miniaturization for improving portability various interfaces are being developed as input devices. Electronic devices are made smaller, the gesture recognition technology using the touch-based interface is favored for easy editing. In addition, user focus primarily on the simplicity of intuitive interfaces which propels further research of gesture based interfaces. In particular, the fingers in these intuitive interfaces are simple and fast which are users friendly. Recently, the single and double finger gestures are becoming more popular so more applications for these gestures are being developed. However, systems and software that employ such finger gesture lack consistency in addition to having unclear standard and guideline development. Method: In order to learn the application of these gestures, we performed the sketch map method which happens to be a method for memory elicitation. In addition, we used the MIMA(Meaning in Mediated Action) method to evaluate gesture interface. Results: This study created appropriate gestures for intuitive judgment. We conducted a usability test which consisted of single and double finger gestures. The results showed that double finger gestures had less performance time faster than single finger gestures. Single finger gestures are a wide satisfaction difference between similar type and difference type. That is, single finger gestures can judge intuitively in a similar type but it is difficult to associate functions in difference type. Conclusion: This study was found that double finger gesture was effective to associate functions for web navigations. Especially, this double finger gesture could be effective on associating complex forms such as curve shaped gestures. Application: This study aimed to facilitate the design products which utilized finger and hand gestures.

• International Journal of Concrete Structures and Materials
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• 제10권2호
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• pp.163-175
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• 2016

This paper presents a revised procedure for computation of double-K fracture parameters of concrete split-tension cube specimen using weight function of the centrally cracked plate of finite strip with a finite width. This is an improvement over the previous work of the authors in which the determination of double-K fracture parameters of concrete for split-tension cube test using weight function of the centrally cracked plate of infinite strip with a finite width was presented. In a recent research, it was pointed out that there are great differences between a finite strip and an infinite strip regarding their weight function and the solution of infinite strip can be utilized in the split-tension specimens when the notch size is very small. In the present work, improved version of LEFM formulas for stress intensity factor, crack mouth opening displacement and crack opening displacement profile presented in the recent research work are incorporated. The results of the double-K fracture parameters obtained using revised procedure and the previous work of the authors is compared. The double-K fracture parameters of split-tension cube specimen are also compared with those obtained for standard three point bend test specimen. The input data required for determining double-K fracture parameters for both the specimen geometries for laboratory size specimens are obtained using well known version of the Fictitious Crack Model.

• 한국자동차공학회논문집
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• 제21권1호
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• pp.121-127
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• 2013

In this study, suspension geometry is controlled to improve vehicle handling performance. The toe and camber of the rear suspension is controlled independently by using a double knuckle structure designed to enhance the vehicle cornering stability. Camber and toe changes in the rear wheel during high speed turning maneuver are important factors that influence the vehicle stability. Toe in the rear outer wheel plays a dominant role in cornering. A control algorithm for the camber and the toe angle input is developed to carry out the control simulation of the vehicle such as single lane change, the steady state cornering, the double lane change and the step steering simulation. Effects of the camber and toe angle control are analyzed from the computer simulations. A double lane change simulation revealed that the suspension mechanism with variable camber angle and variable toe angle decreases the peak body slip angle and peak yaw rate, 50% and 10%, respectively.

• 센서학회지
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• 제26권1호
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• pp.60-65
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• 2017

This paper describes the low noise and low power IC using the opamp sharing technique for the capacitive micro-sensor sensing platform. The proposed IC reduces noise using correlated double sampling (CDS) and reduces power consumption using the opamp sharing technique. The IC is designed to be fully programmable, and can be digitally controlled by serial peripheral interface (SPI). The power consumption and the integrated input referred noise are 1.02 mW from a 3.3 V supply voltage and $0.164aF_{RMS}$ with a bandwidth of 400 Hz. The capacitive sensitivity, the input-output linearity and the figure of merits (FoM) are 2.5 mV/fF, 2.46 %FSO, and 8.4, respectively.

• 한국자동차공학회논문집
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• 제9권5호
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• pp.157-164
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• 2001

This paper performs static and dynamic tests of a multi-leaf spring and a tapered leaf spring to investigate their hysteretic characteristics. In the static test, trapezoidal input load is applied with 0.1Hz excitation frequency and with zero initial loading conditions. In the dynamic test, sinusoidal input load is applied with five excitation amplitudes and three excitation frequencies. In these tests, static and dynamic hysteretic characteristics of the multi-leaf spring and the tapered leaf spring are compared, and, the effects of excitation amplitudes and frequencies on dynamic spring rate are also shown. In this paper, actual vehicle tests are performed to study the effects of hysteretic characteristics of the large-sized truck's handling performance. The multi-leaf spring or the tapered leaf spring is used in the front suspension. The actual vehicle test is performed in a double lane change track with three velocities. Lateral acceleration, yaw rate and roll angle are measured using a gyro-meter located at the mass center of the cab. The test results showed that a large-sized truck with a tapered leaf spring needs to have an additional apparatus such as roll stabilizer bar to increase the roll stabilizer due to hysteretic characteristics.

• 한국멀티미디어학회논문지
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• 제11권3호
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• pp.323-330
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• 2008

본 논문에서는 지문입력에서 회전에 의한 오차를 줄이는 방법으로 기존의 지문 입력기를 개선한 새로운 지문 입력 방법을 제안한다. 일반적인 지문 센서는 센서 위에 손가락을 올려서 지문 영상을 획득하는데 주의를 해도 회전이 발생하여 인식률에 영향을 미친다. 개선된 입력 방법은 엄지와 검지의 사이에 지문입력기를 두어 회전을 최소화하는 방법이다. 반도체 지문 입력기를 양쪽으로 부착하여 엄지와 검지를 동시에 집게 형태로 쥐어서 지문을 입력하는 방법이다. 이 방법은 지문을 획득할 때 마다 거의 같은 각도를 유지한다. 실험결과 제안된 방법이 인식률이 향상되었다. 단점으로는 하드웨어 비용이 더 추가 된다.

• 한국컴퓨터정보학회논문지
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• 제20권1호
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• pp.119-125
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• 2015

본 논문에서는 모바일 환경에서 훔쳐보기 공격에 안전하면서도 사용자 편의성이 뛰어난 패스워드 입력 방식을 제안한다. 제안 기법은 기존의 PIN방식과 같은 숫자 패스워드 입력 방식이다. 하나의 버튼은 숫자와 색, 두가지의 정보를 이중으로 표시하도록 한다. 사용자는 한 버튼 내에 있는 색이나 숫자 정보 중 하나를 선택하여 패스워드로 입력하도록 한다. 제안한 기법에서 공격자는 사용자가 색과 숫자 어느 것을 입력한 것인지 모르기 때문에, 훔쳐보기 공격으로부터 안전할 수 있다. 또한 숫자와 색 정보의 무작위 변경을 통하여 스머지(Smudge) 공격과 패스워드 추측 공격에도 강인하도록 한다.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2004년도 추계학술발표대회 개요집
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• pp.123-124
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• 2004

This study was investigated on the impact toughness and microstructure of welded metal and heat affected zone for Hi Nitrogen TiN Steel. With welding procedures, welding heat input applied were 30, 79 and 264 kJ/cm. TiN steel has shown very small prior austenite grain size for all the welding heat input applied, which was considered to result from the effect of TiN particles. In case of single SAW and EGW welding, the dilution rate of base metal into the weld was not high, resulting that there were no significant effects of base metal chemical composition on the mechanical properties of welds. However, TSAW with double Ypreparation carried very high dilution rate so that TiN steel has impaired the toughness of weld metal because N content in the weld was increased through the dilution of base metal.