• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.352.1-352.1
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• 2016

양자점은 나노미터 크기의 반도체 결정으로 밴드갭에 따라 광학적, 전기적 성질이 달라지는 독특한 성질을 가지는 형광물질으로 활발히 연구되고 있다. 중금속을 기반으로 한 양자점은 높은 발광효율과 광안전성을 가지며, 가시광선 영역에서 빛을 내는 특징을 가지고 있다. 그러나 중금속을 사용하기 때문에 독성이 있어 인체나 환경에 유해하여 응용 연구에 제한적이다. 반면에, 탄소 기반의 양자점은 중금속 기반의 양자점과 비슷한 성질을 가질 뿐만 아니라, 높은 용해도와 낮은 독성으로 인해 생체적합성이 높다는 장점이 있다. 이를 이용하여 발광다이오드(LEDs), 태양전지, 광촉매 뿐만 아니라 바이오이미징, 바이오센서 등 생물학분야에도 응용 될 수 있다. 본 연구에서는 Bottom-up 합성 방법으로 유기전구체를 이용하여 질소를 함유하고 있는 양친매성 탄소 양자점(N-GQDs)을 합성하였다. 합성에 사용한 유기전구체는 기존에 보고된 유기전구체와 다르게 반응 진행 중에도 pH 측정 결과 중성을 나타내며, 반응 온도($225^{\circ}C$)와 유사한 온도에서도 pH 값은 여전히 6.0 이상의 값을 나타냈다. 중성을 띄는 특징으로 인해 추가적인 산제거 과정이나 표면안정화 과정이 필요 없다는 장점을 가지고 있다. 합성된 N-GQDs는 높은 결정성의 원형구조를 가지며, 원자힘현미경(AFM) 분석을 통해 높이가 ~ 1.5 nm 미만으로 3층 이하의 두께로 형성되었음을 확인하였다. 또한, 적외선 분광법(FT-IR) 분석을 통해 O-H기, 방향족 고리의 C = C (또는 C = N)기 및 C-N기가 각각 ~3250, ~1670과 ~1140 cm-1에서 확인할 수 있다. 합성된 양자점을 유기태양전지의 active layer에 소량(2 wt%) 첨가하여 양자점의 광학적, 전기적 성질을 확인하였다. 비교군 유기태양전지보다 N-GQDs가 첨가된 유기태양전지의 외부양자효율(PCE)이 7.3%에서 8.4%로 약 20%가 증가하는 것을 보였다. 이는 양자점이 상대적으로 흡수가 약한 단파장 영역의 빛을 흡수하고 PL을 내어 active layer로 에너지 트랜스퍼 현상이 일어나 전자전달을 원활하게 해 주기 때문이다. 앞으로 본 연구의 가능성과 추가적인 연구를 통해 더 많은 분야에 응용되기를 기대한다.

• Journal of the Korean Society of Fashion and Beauty
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• v.4 no.1 s.7
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• pp.60-64
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• 2006

에센셜 오일은 고대로부터 향을 즐기거나 직접 상처 부위에 바르는 등의 다양한 방법으로 사용해 왔다. 일반적으로 에센셜 오일을 얻을 수 있는 허브와 스파이스는 약 200종 정도이며 흔히 주변에서 볼 수 있는 것으로는 레몬이나 오렌지, 장미, 제라늄, 민트 등이 있다. 이들 식물의 꽃잎(장미), 잎사귀(유칼립투스), 뿌리(베티본), 고목(샌달우드), 송진(프랭킨센스), 줄기(버베나), 열매(베르가못) 등 여러 부분에서 독자적인 방법으로 추출할 수 있는 에센셜 오일은 식물의 강한 생명의 힘으로 종종 언급되었다. 이는 방향성, 비지방성의 100% 천연의 식물에서 추출한 물질이며, 저마다의 고유한 향과 각기 다른 독특한 생명력과 치유능력을 가지고 있다. 이러한 에센셜 오일을 사용함에 있어서 우리는 감정 치유와 신체 건강을 향상시킬 수 있다. 모든 에센셜 오일은 항-박테리아, 항-바이러스 또는 항균성을 지니고 있다. 연구 조사에 따르면 아로마(향)는 인간의 감정 센서에 직접적인 영향을 끼치는데 이는 우리 신체의 감각 중심의 뇌에 직접적으로 아로마 향이 투입되기 때문이다. 우리의 후각을 통해 뇌 시스템을 직접 통과하여 감정, 행동, 냄새를 판단하는 것을 총괄하게 된다. 항상 아름다운 냄새를 통해 즐거워 하고 우리의 감정 균형을 유지시키므로 에센셜 오일을 사용함에 있어 그 향기가 우리에게 즐거움을 주는 것은 중요한 일이다. 이 오일을 통해 우리의 감각신경이 균형을 유지하게 될 것이다. 이러한 에센셜 오일을 이용하여 마음의 건강, 정신의 건강, 신체의 건강을 향상시키며 유지할 수 있도록 유지, 관리하는 것이 아로마테라피이다. 아로마테라피는 적게는 담배로부터 향수까지 광범위하게 가장 화려한 글로 설명되어 왔다. 에센셜 오일을 사용함에 있어 우리 신체의 가장 좋은 투입 방법으로 마사지 법이 있으며 우리 피부는 에센셜 오일을 놀라울 만큼 빠르게 흡수해 낸다. 이러한 효능의 에센셜 오일을 피부관리시에 적용하여 신체의 건강뿐만 아니라, 정신의 건강을 향상시키며 유지 할 필요가 있다고 본다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.3
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• pp.315-321
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• 2014

This paper presents an integrated chassis control system with fail safety using optimum yaw moment distribution for a vehicle with steer-by-wire and brake-by-wire devices. The proposed system has two-level structure: upper- and lower-level controllers. In the upper-level controller, the control yaw moment is computed with sliding mode control theory. In the lower-level controller, the control yaw moment is distributed into the tire forces of active front steering(AFS) and electronic stability control(ESC) with the weighted pseudo-inverse based control allocation(WPCA) method. By setting the variable weights in WPCA, it is possible to take the sensor/actuator failure into account. In this framework, it is necessary to optimize the variables weights in order to enhance the yaw moment distribution. For this purpose, simulation-based tuning is proposed. To show the effectiveness of the proposed method, simulations are conducted on a vehicle simulation package, CarSim.

• Journal of the Korean Society for Nondestructive Testing
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• v.31 no.5
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• pp.472-478
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• 2011

The purpose of this study was to analyze the kinetic effect of Soft-$golf^{TM}$ instrument on the human body structure. To analyze the kinetic effect of Soft-$golf^{TM}$ instrument, Golf swing using Soft-$golf^{TM}$ instrument and regular golf instrument was captured. And then Upper limbs and lumbar joint torques was calculated via computer simulation. Five man participated this study. Subjects performed golf swing using a regular golf and Soft-$golf^{TM}$ instrument. Golf swing motion was captured using three position sensor, active infrared LED maker and force plate. Golf swing model was generated and simulated using ADAMS/LifeMOD program. As a results, joint torque during Soft-golf swing were lower than regular golf swing. Thus soft-golf swing have joint load lower than regular golf swing and contribute to reduce joint injury.

• The Journal of Korea Robotics Society
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• v.15 no.4
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• pp.309-315
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• 2020

This study shows a control strategy that acquires both precision and manipulation sensitivity of remote center motion with manual traction for a surgical assistant robot. Remote center motion is an essential function of a laparoscopic surgical robot. The robot has to keep the position of the insertion port in a three-dimensional space, and general laparoscopic surgery needs 4-DoF (degree-of-freedom) motions such as pan, tilt, spin, and forward/backward. The proposed robot consists of a 6-axis collaborative robot and a 2-DoF end-effector. A 6-axis collaborative robot performs the cone-shaped trajectory with pan and tilt motion of an end-effector maintaining the position of remote center. An end-effector deals with the remaining 2-DoF movement. The most intuitive way a surgeon manipulates a robot is through direct teaching. Since the accuracy of maintaining the remote center position is important, direct teaching is implemented based on position control in this study. A force/torque sensor which is attached to between robot and end-effector estimates the surgeon's intention and generates the command of motion. The predefined remote center position and the pan and tilt angles generated from direct teaching are input as a command for position control. The command generation algorithm determines the direct teaching sensitivity. Required torque for direct teaching and accuracy of remote center motion are analyzed by experiments of panning and tilting motion.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.4
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• pp.95-100
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• 2004

This paper represents the development of a CLS(Control Loading System) for a target a airplane (KT-1) with mechanical linkage reversible flight control system. The system is composed of mechanical frame, controller, sensing part to measure the force from the stick, driving system generating the reaction forces. The DS1103 DSP(Digital Signal Processor) of the dSpace Corp. was used as the controller. The control algorithm of the CLS and the operational environment including monitoring software and evaluation tools are described. The evaluation of the system was conducted according to the requirement specification. The results of the test were analyzed by comparing with the actual data of the target airplane.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.246-250
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• 2003

In this study, two new types of micro-grippers in which micro-fingers are actuated by piezoelectric multi-layer benders and stacks are introduced for the manipulation of micrometer-sized objects. First, we constructed a 3-chopstick-mechanism tungsten gripper, which is composed of three chopsticks: two are designed to grip micro-objects, and tile third is used to help grasp and release the objects through overcoming especially electrostatic force among some surface effects including electrostatic, van der Waals forces and surface tension. Second, a 2-chopstick-mechanism silicon micro-gripper that uses an integrated force sensor to control the gripping force was developed. The micro-gripper is composed of a piezoelectric multilayer bender for actuating the gripper fingers, silicon fingertips fabricated by use of silicon-based micromachining, and supplementary supports. The micro-gripper is referred to as a hybrid-type micro-gripper because it is composed of two main components; micro-fingertips fabricated using micromachining technology to integrate a very sensitive force sensor for measuring the gripping force, and piezoelectric gripper finger actuators that are capable of large gripping forces and moving strokes. The gripping force signal was found to have a sensitivity of 667 N/V. To the design of each of components of both of the grippers. a systematic design approach was applied, which made it possible to establish the functional requirements and design parameters of the micro-grippers. The micro-grippers were installed on a manual manipulator to assess its performance in tasks such as moving micro-objects from one position to a desired position. The experiment showed that the micro-grippers function effectively.

• Journal of the Korean Data and Information Science Society
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• v.26 no.5
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• pp.1117-1128
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• 2015

In order to secure an important competitive advantage in manufacturing business, an automation and information system from manufacturing process has been introduced; however, small and medium enterprises have not met the power of information in the manufacturing fields. They have been managing the manufacturing process that is depending on the operator's experience and data written by hand, which has limits to reveal cause of defective goods clearly, in the case of happening of low-grade goods. In this study, we analyze critical factors which affect the quality of some manufacturing process in terms of 4M. We also studied the automobile parts processing of the small and medium manufacturing enterprises controlled with data written by hand so as to collect the data written by hand and to utilize sensor data in the future. Analysis results show that there is no deference in defective quantity in machines, while raw materials, production quality and task tracking have significant deference.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.4B
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• pp.647-658
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• 2010

Many localization schemes estimate the locations of radio nodes based on the physical locations of anchors and the connectivity from the anchors. Since they only consider the knowledge of the anchors without else other nodes, they are likely to have enormous error in location estimate unless the range information from the anchors is accurate or there are sufficiently many anchors. In this paper, we propose a novel localization algorithm with the location knowledge of anchors and even one-hop neighbors to localize unknown nodes in the uniform distance from all the one-hop neighbors without the range information. The node in the uniform distance to its all neighbors reduces the location error relative to the neighbors. It further alleviates the location error between its actual and estimated locations. We evaluate our algorithm through extensive simulations under a variety of node densities and anchor placement methods.

• The Journal of the Korea Contents Association
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• v.8 no.8
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• pp.244-252
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• 2008

This research differentiate the technique of Jungkwon-jirugi, one of the basic movements of Taekwondo, into two movements stop-jirugi and push-jirugi and gives analysis of the impulse, acceleration and velocity in the point of motor control. For this, we tried graphic analysis using an acceleration sensor and high speed camera which was made from USA in 2005 and took pictures at 250 frames per second. We reached the following conclusions. First, the acceleration wave of push-jirugi was a period longer than stop-jirugi, meaning that the push-jirugi motion asserts force for a longer time. Second, the acceleration and velocity graph shows that the highest velocity occurs on the point when the acceleration begins to decrease right after reaching its maximum. Third, according to the image analysis using the high speed camera, we could find out that the shoulder is pushed a little even in the stop-jirugi motion.