• Journal of the Korean Data and Information Science Society
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• 제18권4호
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• pp.1033-1043
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• 2007

The multi layer perceptron for segmenting objects in images only uses the input windows that are made from a image in a fixed size. These windows are recognized so each independent learning data that they make the performance of the multi layer perceptron poor. The poor performance is caused by not considering the position information and effect of input windows in input images. So we propose a new approach to add the position information and effect of input windows to the multi layer perceptron#s input layer. Our new approach improves the performance as well as the learning time in the multi layer perceptron. In our experiment, we can find our new algorithm good.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 신호처리소사이어티 추계학술대회 논문집
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• pp.199-202
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• 2003

In this paper, we propose a new 3D coding method for heterogeneous systems over enhanced Access Grid (e-AG) with 3D display using spatio-temporal scalability. The proposed encoder produces four bit-streams: one base layer and enhancement layer l, 2 and 3. The base layer represents a video sequence for left eye with lower spatial resolution. An enhancement layer l provides additional bit-stream needed for reproduction of frames produced in base layer with full resolution. Similarly, the enhancement layer 2 represents a video sequence for right eye with lower spatial resolution and an enhancement layer 3 provides additional bit-stream needed for reproduction of its reference pictures with full resolution. In this system, temporal resolution reduction is obtained by dropping B-frames in the receiver according to network condition. The receiver system can select the spatial and temporal resolution of video sequence with its display condition by properly combining bit-streams.

• 한국정밀공학회지
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• 제12권11호
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• pp.132-139
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• 1995

Turbulent boundary layer pressure fluctuation exerted on the surface of a structure can give rise to a elastic stress wave on the surface of the structure. The stress wave so called surface wave, will not only propagate along the surface of structure but also penerate into the structure. To reduce the transmission of stress wave into the structure the elastomer layer is usually attactched on the surface of structure. The transfer function, which is defined herein as the ratio of stress waves at the surface and bottom of the elastomer layer, is derved by use of the cylindrical coordinates system. The elastodynamics of the elastomer layer subjected to the turbulent boundary layer pressure fluctuation is represented by the simplified one degree-of-freedom model for easy prediction of the stress wave transmission as well as efficient design of the elastomer layer.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.981-984
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• 1997

This paper deals with the relation of cutting conditions and damaged layer by investigating cutting force, cutting temperature and residual stress in high speed machining. Damaged layer was measured using optical microscope on samples prepared by metallographic techniques. The scale of this damaged layer depends upon characteristics of cutting force and cutting temperature. Damaged layer depth increases with feed per tooth and radial depth. In a different another way, damaged layer remains almost unchanged according to spindle speed. Therefore, the effective method for decreasing damaged layer is that cut down feed per tooth and radial depth.

• 전기학회논문지
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• 제56권12호
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• pp.2166-2172
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• 2007

In this study a low-signal equivalent circuit based on the Double Schottky Barrier model is proposed for ZnO-based varistor. Since pin-lead inductance and stray capacitance are considered in pin-lead type ZnO varistor these inductance and capacitance could be removed from the experimental dielectric data of the varistor. According to the equivalent circuit simulation results the higher the varistor-voltage of varistor sample the capacitance of dielectric layer is larger, and the capacitances of semiconducting layer and depletion layer are smaller, while the parallel resistances of semiconducting layer and depletion layer are more larger values. Spectra of the dielectric loss factor $tan{\delta}$ show 2 peaks in low frequency and high frequency regions respectively. The low-frequency peak is due to the relaxation by deep donors and the high-frequency peak is due to the relaxation by shallow donors. Above results are well consistent with the theoretical mechanism of ZnO varistor.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1999년도 추계학술대회 논문집 - 한국공작기계학회
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• pp.190-196
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• 1999

Hot forgeability of STD 61 steel was boronzed in boronizing paste mainly consisted of B4C and Na2B4O7 at various temperatures and times. Microhardness and thickness of boride layers were measured and distributions of B, Si, Cr and V on the cross section of specimen were observed by EPMA line analysis. Microscopic examination and results of EPMA showed that the boride layer consisted of two layers outer layer of FeB and inner layer of Fe2B. Microhardness of these boride layers was in the range of Hv 1800~2300. Thickness of boride layer increased with times and temperatures. Si-rich $\alpha$ layer was formed between boride layer and matrix. Element such as Cr concentration as Cr23(B, C)6 beneath the boride layer.

• The Korean Journal of Ceramics
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• 제3권3호
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• pp.163-168
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• 1997

Most of heteroepitaxial $\beta$-SiC thin films have been successfully grown on Si(100) adapting a carburizing process, by which a few atomic layers of substrate surface is chemically converted to very thin SiC layer using hydrocarbon gas sources. Using an organo-silicon precursor, bis-trimethylsilymethane (BTMSM, [$C_7H_{20}Si_2$]), heteropitaxial $\beta$-SiC thin films were successfully grown directy on Si substrate without a carburized buffer layer. The defect density of the $\beta$-SiC thin films deposited without a carburized layer was as low as that of $\beta$-SiC films deposited on carburized buffer layer. In addition, void density was also reduced by the formation of self-buffer layer using BTMSM instead of carburized buffer layer. It seems to be mainly due to the characteristic bonding structure of BTMSM, in which Si-C was bonded alternately and tetrahedrally (SiC$_4$).

• 수산해양교육연구
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• 제5권2호
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• pp.128-137
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• 1993

This paper presents a new concept to reduce turbulent frictional drag by injecting micro-bubble into buffer layer of turbulent boundary layer on flat plate. The buffer layer of boundary was specified by minus velocity gradient of law of the wall. When the buffer layer region of turbulent boundary layer is filled with micro-bubble of air and viscous of the region is kept low, the velocity profile in the region should be changed substantially. Then the Reynolds stress in the buffer layer region becomes less, which guide to higher velocity gradient there. It results in reduction of velocity gradient at the viscous sublayer, which gives the reduction of shear stress at the wall.

• 대한전자공학회논문지
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• 제23권4호
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• pp.484-489
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• 1986

A device with variable stepped oxide layer along the edge region of Schottky junction have been designed and fabricated. The effect of this stepped oxide layer in the edge region improves the breakdown voltage as a result of the by increase of the depletion layer width, and decreases the leakage current as compared to the effect of conventional field oxide layer, when the reverse voltage was applied. Experimental results shown that the Schottky diode with the the reverse voltage was applied. Experimenal results show that the Schottky diode with the optimal stepped oxide layer maintains nearly ideal I-V characteristics and excellent breakdown voltage(170V) by reducing the edge effect inherent in metal-semiconductor contacts. The optimal conditions of stepped oxide layer are 1700\ulcornerin thickness and 10\ulcorner in length.

• 한국지구과학회지
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• 제25권7호
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• pp.629-636
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• 2004

구름이 유입하는 경우 해양대기경계층의 발달을 분석하기 위하여, 울릉도에서 관측한 레윈존데 자료와 AWS 자료, 위성사진, 동해에 설치된 부이 자료를 이용하였다. 이 자료를 이용하여 열의 이류와 표층 열속, 구름 유입에 따른 복사에너지를 추정하였다. 혼합층 내의 열 변화 및 혼합층의 발달을 표층 열속과 구름에 의한 장파복사속으로 설명하였다. 열속의 변화를 알아보기 위해 벌크법을 이용하였다. 울릉도, 동해상의 부이, 포항에서 관측한 자료를 이용한 열수지 방정식으로 대기경계층의 열보존 관계를 분석하였다. 구름의 유입으로 인해 일몰 후 지면의 복사냉각이 방해되고, 구름에서 장파복사가 방출된다. 그로 인해 야간에 오히려 기온이 증가하였다. 또 남서쪽으로부터 따뜻한 공기가 이류되어, 하층 대기의 온도를 증가시켰다. 이러한 이유로 혼합층이 파괴되지 않고, 잔류층을 형성하며 남아있었다.