• 한국식생활문화학회지
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• 제24권3호
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• pp.308-314
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• 2009

In this study, we examined the composition of catechins, theaflavins and alkaloids in leaves during processing to fermented black tea, which is produced by withering, roll breaking, and fermentation of Korean Yabukida tea plant. In addition, we determined the optimal conditions for the production of fermented black tea. The average moisture content in fresh leaves was 70.85%, which dropped to 3.07% in fermented black tea at the last stage of production. When the leaves were analyzed by HPLC, seven types of catechins, four types of theaflavins and three types of alkaloids were identified. The levels of catechins, theaflavins, and alkaloids were then evaluated after being processed into fermented tea. From these experiments, we found that the level of theaflavins, which determines the property of the tea, increased during fermentation. This effect resulted from the change in EGCG, ECG, EGC, EC during the process of fermentation. We also found that the maximal amount of theaflavins was created after 1-2 hours of fermentation. Thus, our results imply that the best condition for producing fermented black tea would be to ferment for 1-2 hours.

• 한국인쇄학회지
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• 제25권1호
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• pp.53-64
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• 2007

Gravure printing is the most useful printing process than any other engraving printing method. According to the cell which is variable size and depth, ink is transferred substrates. So, the amount of ink from cells has a great effect on the qualities of final printed products. The variables effect on the printability of final products are proportion of the width and length, the rhelogical properties, roll speed etc. However the mechanism of gravure is difficult to study scientifically because of high speed and excessively small size of the cell. To approach the mechanism we experimented the real test by using gravure printability. The condition of variables of IGT is pressure and velocity. By using Polyflow 3. 10. 0 simulation software, we built up the theoretical model under the constant variables. Then, we compared the real test with the simulation results. Therefore, it is studied the mechanism of gravure scientifically and it can be analysed the effect of the variable conditions.

• 한국자동차공학회논문집
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• 제6권1호
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• pp.163-181
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• 1998

In this study, the objective is determine the optimal design variable of engine mount system using the rubber mount of bush-type which is usually utilized in passive control to minimize vibrations of vehicle body or transmission from engine into body. The engine model adopted in this study is 4-cylinder, 4-stroke gasoline engine support- ed by 4-points. The system is modelled in 10 d.o.f.-rigid body motion of the engine & transmission in 6 d.o.f., elastic motion of vehicle body in 4 d.o.f.(1st torsional, 1st vertical and 1st & 2nd lateral bending vibration mode). To consider the elastic motion of vehicle body, find the eigenvalues and mode shapes of vehicle body by nodal testing and then determine the modal masses and stiffnesses of the body. The design variables of the engine mount system are locations, stiffness and damping coefficients of the rubber mounts(28 design variables). In case of considering the torque-roll axis for the engine, the design variables of the mount system are reduced to 22 design variables. The objective functions in optimal design process are considered by three cases, that is, 1) transmitted forces through engine mounts, 2) acceleration components of generalized coordinates for the vibration of vehicle body, 3) acceleration of specified location(where gear box) of body. three case are analyzed and compared with each other.

• 대한기계학회논문집A
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• 제24권7호
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• pp.1650-1660
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• 2000

Continuous casting process has been adopted increasingly in recent years to save both energy and labor. It has experienced a rapid development in the production of semi-finished steel products, rep lacing the conventional route of ingot casting and rolling. In order to achieve this merit, however, more studies about the mechanism between roll and slab are needed. In this paper, a dynamic bulging in steel cast slabs was simulated by considering the solidification and heat transfer. This study is to prevent internal cracks of a slab in a bending and unbending zone. The value of moving strand shell bulging between two supporting rollers under the ferrostatic pressure and slab-self weight has been calculated in terms of creep and elasto-plasticity. The strain and strain rate distributions in solidified shell undergoing a series of bulging are calculated with working boundary conditions.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2004년도 ICEIC The International Conference on Electronics Informations and Communications
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• pp.237-243
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• 2004

A multichannel smart sound sensor capable to detect and identify sound events in noisy conditions is presented in this paper. Sound information extraction is a complex task and the main difficulty consists is the extraction of high­level information from an one-dimensional signal. The input of smart sound sensor is composed of data collected by 5 microphones and its output data is sent through a network. For a real time working purpose, the sound analysis is divided in three steps: sound event detection for each sound channel, fusion between simultaneously events and sound identification. The event detection module find impulsive signals in the noise and extracts them from the signal flow. Our smart sensor must be capable to identify impulsive signals but also speech presence too, in a noisy environment. The classification module is launched in a parallel task on the channel chosen by data fusion process. It looks to identify the event sound between seven predefined sound classes and uses a Gaussian Mixture Model (GMM) method. Mel Frequency Cepstral Coefficients are used in combination with new ones like zero crossing rate, centroid and roll-off point. This smart sound sensor is a part of a medical telemonitoring project with the aim of detecting serious accidents.

• 한국가시화정보학회:학술대회논문집
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• 한국가시화정보학회 2002년도 추계학술대회 논문집
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• pp.67-72
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• 2002

Today, the research to examine a fact that interaction between the air and the fluid free surface affects the steady state flow and air. We proved the interaction between vortex pairs and free surface on each condition that is created by the end of delta wings. another purpose of this study is to investigate the effect of surface active material which can change the surface tension and we must consider when we refer to turbulent flow on surface tension. therefore, this research examined the growth process of vortex pairs on condition of clean, contaminated free surface and wall after we made vortex pairs through counter rotating flaps. The results of this study suggest that vortex pairs in clean free surface rise safely but the vortex pairs in contaminated free surface and rigid, no slip is made secondary vortex or rebounding. However the secondary vortex in rigid, no slip is stronger than before, and we can find the vortex shape which roll up more completely. However, these will disappear by the effect of wall.

• 한국지능시스템학회논문지
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• 제19권5호
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• pp.683-688
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• 2009

본 논문에서는 비젼을 이용한 영상처리 기술을 기반으로 비접촉식 미세 측정 광학기에 의해 측정된 이미지를 템플릿 매칭과 B-Spline 보간법에 의해 보다 빠르고, 정밀한 복원 기법을 제안한다. 이를 위해 먼저 각각의 이미지로부터 매칭 템플릿과 피 매칭 템플릿을 검출한다. 그런 다음 기준면으로부터 두 이미지의 중첩되는 부분의 롤, 피치, 요 오차를 보정하여 정합시킨다. 그리고 B-Spline 보간법에 의해 정합된 부분을 연속화한다. 마지막으로, 제안된 방법은 실험을 통해 그 응용 가능성을 증명한다.

• 대한금속재료학회지
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• 제49권8호
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• pp.664-670
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• 2011

3-ply Mg/Al/STS clad-metal was fabricated by the roll bonding process. An interfacial reaction layer was formed at the Mg/Al interface at and above $300^{\circ}C$ whereas no interfacial reaction layer was observed up to $400^{\circ}C$. The effect of the interfacial reaction layer on the mechanical and fracture properties in clad metals after heat treatments were investigated The chemical compositions were analyzed at the Mg/Al interface by an Energy dispersive X-ray analysis (EDX). A tension test was performed to examine the interfacial cracking properties. The Mg layer fractured first, causing a sudden drop of the stress and Al/STS layer continued to deform until the final fracture. Periodic cracks and crack propagation was observed at the reaction layer between Mg and Al.

• 대한방사선치료학회지
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• 제24권2호
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• pp.115-121
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• 2012

목 적: 양성자 치료는 DIPS (Digital Imaging Positioning System)를 이용하여 기준이 되는 DRR (Digital Reconstruction Radiography) 영상과 당일 치료 과정에서 얻은 X-ray 영상의 해부학적 구조를 비교하여 교정 값을 얻어 PPS (Patient Positioning System)를 교정 후 치료한다. PPS는 환자 셋업의 정확성을 위해 6방향(X축 Lateral, Y축 Longitudinal, Z축 Vertical, Rotation, Pitch, Roll)의 이동을 기반으로 움직인다. 따라서 DIPS의 교정 값과 PPS 움직임 구현성의 정확성 평가가 필요하다. 이에 자체 제작한 PPS QA 팬텀을 이용하여 PPS의 정확성을 평가하고자 한다. 대상 및 방법: 환자의 해부학적 구조를 대신 할 납 볼이 부착된 PPS QA 팬텀을 기준점에 셋업 한다. 임의의 수치 값으로 PPS 6 방향의 움직임을 만들어 PPS QA 팬텀을 이동시킨다. DIPS로 얻은 교정 값을 적용 후 기준점과 기준점으로 돌아온 PPS QA 팬텀과의 교정 값이 허용 범위 내에 들어오는지 평가한다. 결 과: 기준점에 위치한 PPS QA 팬텀의 X축, Y축, Z축의 3개의 좌표를 함께 1 cm에서 5 cm까지 1 cm씩 이동한 후 기준점과의 평균 교정 값은 PPS 6축에서 각각 0.04 cm, 0.026 cm, 0.022 cm, $0.22^{\circ}$, $0.24^{\circ}$, $0^{\circ}$이다. PPS QA 팬텀의 6방향의 이동 좌표계를 모두 1과 2만큼 이동 시켰을 때 평균 교정 값은 1 이동 시 0.06 cm, 0.01 cm, 0.02 cm, $0.1^{\circ}$, $0.3^{\circ}$, $0^{\circ}$이었고, 2만큼 이동 시에 0.02 cm, 0.04 cm, 0.01 cm, $0.3^{\circ}$, $0.5^{\circ}$, $0^{\circ}$이었다. 결 론: 교정 값을 평가한 결과 Lateral, Longitudinal, Vertical의 경우 허용 범위인 0.5 cm Rotation, Pitch, Roll의 경우 허용 범위 $1^{\circ}$ 안에 모두 들어오는 것을 알 수 있었다. 하지만 더욱 정확한 양성자 치료를 위해 DIPS의 이미지 질 개선과 DIPS 매칭 시스템의 발전 노력, 정기적인 장비 관리를 함으로써 현재 발생하는 기계적인 오차를 더욱 줄여나가야 하겠다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.1787-1790
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• 2005

We have developed satellite devices for fine attitude control of the Science & Technology Satellite-2 (STSAT-2) scheduled to be launched in 2007. The analog sun sensors which have been continuously developed since the 1990s are not adequate for satellites which require fine attitude control system. From the mission requirements of STSAT-2, a compact, fast and fine digital sensor was proposed. The test of the fine attitude determination for the pitch and roll axis, though the main mission of STSAT-2, will be performed by the newly developed FDSS. The FDSS use a CMOS image sensor and has an accuracy of less than 0.01degrees, an update rate of 20Hz and a weight of less than 800g. A pinhole-type aperture is substituted for the optical lens to minimize the weight while maintaining sensor accuracy by a rigorous centroid algorithm. The target process speed is obtained by utilizing the Field Programmable Gate Array (FPGA) in acquiring images from the CMOS sensor, and storing and processing the data. This paper also describes the analysis of the optical performance for the proper aperture selection and the most effective centroid algorithm.