• 한국반도체및디스플레이장비학회:학술대회논문집
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• 한국반도체및디스플레이장비학회 2002년도 추계학술대회 발표 논문집
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• pp.85-90
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• 2002

$RuO_2$/GaN and related contacts were investigated for Schottky contacts in GaN-Based optical and electronic devices. We demonstrated that an $RuO_2$ film forms a stable Schottky contact on a GaN layer with a barrier height (${\Phi}_B$) of 1.46 eV and transmittance of 70% in the visible and near UV region. $RuO_2$/GaN Schottky diode showed a breakdown at over -50V and leakage current of only 0.3 nA at -5V. The $RuO_2$/GaN Schottky type photodetector had the UV/Visible rejection ratio of over $10^5$ and the responsivity of 0.23 A/W at 330 nm. The $RuO_2$ gate AlGaN/GaN EFET exhibited high drain current ($I_d$) of 689.3 mA/mm and high transconductance ($g_m$) of 197.4 mS/mm. Cut-Off frequency ($f_t$) and maximum operating frequency ($f_{max}$) were measured as 27.0 GHz and 45.5 GHz, respectively.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권1호
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• pp.277-290
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• 2019

The demand for indoor positioning is increasing day by day. However, the widely used positioning methods today cannot satisfy the requirements of the indoor environment in terms of the positioning accuracy and deployment cost. In the existing research domain, the localization algorithm based on three-dimensional space is less accurate, and its robustness is not high. Visible light communication technology (VLC) combines lighting and positioning to reduce the cost of equipment deployment and improve the positioning accuracy. Further, it has become a popular research topic for telecommunication and positioning in the indoor environment. This paper proposes a surface centroid TOA localization algorithm based on the VLC system. The algorithm uses the multiple solutions estimated by the trilateration method to form the intersecting planes of the spheres. Then, it centers the centroid of the surface area as the position of the unknown node. Simulation results show that compared with the traditional TOA positioning algorithm, the average positioning error of the surface centroid TOA algorithm is reduced by 0.3243 cm and the positioning accuracy is improved by 45%. Therefore, the proposed algorithm has better positioning accuracy than the traditional TOA positioning algorithm, and has certain application value.

• 한국결정성장학회지
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• 제23권5호
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• pp.218-223
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• 2013

본 연구에서는 LCD 또는 LED를 이용한 디스플레이 장치의 BLU 반사판으로 사용할 목적으로 무전해도금에 의하여 플라스틱 기판위에 성장되어진 은 나노코팅의 반사율 특성을 조사하였다. 은 나노코팅의 미세구조는 아주 미세한 나노크기의 은 결정들로 이루어진 다결정 나노코팅인 것을 확인할 수 있었으며 코팅 층의 두께가 증가함에 따라 환원, 석출된 은 나노결정입자의 크기도 비례하여 증가되었다. 은 나노코팅의 두께가 증가함에 따라 가시광선 영역의 반사율이 감소하였으며 파장이 짧을수록 반사율의 감소가 더 심하였다. 나노코팅의 두께 증가에 따른 반사율의 감소는 환원 석출된 은나노결정의 크기와 밀접하게 관련된 것으로 은 결정입자가 클수록 요철의 정도가 심하여 반사율이 감소하는 것으로 생각되어진다. 그래서 가능한 미세한 은 나노결정을 환원, 석출시키고 코팅두께를 얇게 하는 것이 반사율 관점에서 바람직한 것으로 판단되어진다.

• 한국인터넷방송통신학회논문지
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• 제14권1호
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• pp.23-30
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• 2014

LED 조명기구로의 전환은 홈네트워크 등에서 단순히 기계적 연동에 의해 전원제어만이 고려되던 조명기구를 조명과 무선통신이 결합된 하나의 IT 컨버전스(Convergence)로 변환시켰고, 그 구체적인 예가 바로 Visible Light Communication(VLC) 즉 가시광 무선통신이다. VLC의 대표적인 응용으로 고정밀의 실내 위치측정을 기반으로 하는 실내 내비게이션 시스템을 들 수 있다. 본 논문에서는 대형 건물에서 주로 사용되는 형광등 타입의 LED 조명기구와 현재 사용자 단말로 가장 흔하게 사용되는 스마트 기기를 실내 내비게이션 시스템의 구성요소로 고려하는 VLC 기반의 스마트 기기를 이용한 실내 내비게이션 시스템을 모델링하고 구현함으로써 VLC 응용개발의 구현성과 스마트 기기와의 융합성 연구를 보다 용이하게 하고자 한다.

• Journal of Information Technology Applications and Management
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• 제26권6호
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• pp.65-78
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• 2019

This study describes the accounting approach of separating the value chain components that occur between the origin and destination of a country's total exports, and applied this analysis to the nation's information and communication industry. As a result of this study, the analysis results of ICT's global value chain for the United States and China, focusing on Korea, are as follows: First of all, the value added standard was relatively lower than the export amount standard for the information and communication industry. In particular, the gap was starkly visible in the information and communication manufacturing sector, where global vertical specialization was developed relatively. As a representative sector, the computer-related equipment sector exported to China became more specialized vertically than other information and communication industries. Next, the method of participating in vertical specialization of Korea's information and communication sector and its relative position in the global value chain came from domestic products (0.25/35.16) whose total exports, which were double calculated in the case of the U.S. market, returned home. On the other hand, about 32.68 percent returned to the Chinese market. Finally, in the global value chain level, the SW sector occupied a medium vertical culture location for the information and communication equipment sector and the information and communication service sector.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2004년도 춘계학술대회 논문집
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• pp.235-240
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• 2004

The equipment of industrial robot in manufacturing and assembly lines has rapidly increased. In order to achieve high productivity and flexibility, it becomes very important to develop the visual feedback control system with Off-Line Programming System(OLPS). We can save much efforts and time in adjusting robots to newly defined workcells by using OLPS. A proposed visual calibration scheme is based on position-based visual feedback. The calibration program firstly generates predicted images of objects in an assumed end-effector position. The process to generate predicted images consists of projection to screen-coordinates, visible range test and construction of simple silhouette figures. Then camera images acquired are compared with predicted ones for updating position and orientation data. Computation of error is very simple because the scheme is based on perspective projection which can be also expanded to experimental results. Computation time can be extremely reduced because the proposed method does not require the precise calculation of tree-dimensional object data and image Jacobian.

• 한국전기전자재료학회논문지
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• 제27권5호
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• pp.312-316
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• 2014

Photoemission is a process in which photons are converted into free electrons. Photocathodes are the typical materials for the process. They emit electrons when a light is irradiated upon. The traditional method of manufacturing photocathodes is complicated, requires specialized equipment, and is limited very small sized samples. $Cs_3Sb$ photocathode was formed on a substrate in $N_2$ atmospheric conditions. The photocathode formation was a gas phase reaction with the substrate. Vacuum devices were made to test electron emission characteristics of the formed photocathode. Visible light of wavelength 475 nm was used for the primary light source. The results showed high current density and long term stability of the photoelectron emission.

• 한국실내디자인학회논문집
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• 제1호
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• pp.72-75
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• 1992

Lighting made interior space visible and to recognize space itself. Sp9ace and form are established not themselves , but lighting. and dextrous treatment of natural light accomplished poeteic space. Inflowing of lighting in interior space is main factor to decide space character and image . That was recognized in interior space through many centries. At this point, this study was described for that present inflowing of lighting adapting space character and right method in lighting program. The present study is to present the planning method of the most appropriate and the most rational natural lighting in planing for lighting. Under this premise the followings are made ; I. An introduction , the purpose, the sphere, and the method of this study are stated. II, The present writer studied the general characteristics of natural lighting. III. this author studied the factor of decision on control and representation skill of lighting along the following. IV. Analyzing interior space in which the natural lighting is introduced through some literature and case studies. Physics, psychology, structure, equipment, material. V. The last, the author rearranged the results of this study.

• 센서학회지
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• 제27권5호
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• pp.280-293
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• 2018

The conversion of an invisible thermal radiation pattern of an object into a visible image using infrared (IR) thermal technology is very useful to understand phenomena what we are interested in. Although IR thermal images were originally developed for military and space applications, they are currently employed to determine thermal properties and heat features in various applications, such as the non-destructive evaluation of industrial equipment, power plants, electricity, military or drive-assisted night vision, and medical applications to monitor heat generation or loss. Recently, IR imaging-based monitoring systems have been considered for application in agricultural, including crop care, plant-disease detection, bruise detection of fruits, and the evaluation of fruit maturity. This paper reviews recent progress in the development of IR thermal imaging techniques and suggests possible applications of thermal imaging techniques in agriculture.

• 대한기계학회논문집A
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• 제26권9호
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• pp.1727-1735
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• 2002

The usage of beam scanning type laser marker is rapidly increasing in the field of semiconductor equipment. A device called ″beam adjuster″ is employed to adjust the visible diode laser, which points the marking position for various setting. The device is very sensitive to manufacturing tolerance and assembly condition. Axiomatic approach has been applied to the design of the device. An existing design is analyzed based on the Independence Axiom. The existing design is found to violate the axiom. Two new designs are proposed to satisfy the Independence Axiom. The Information Axiom is utilized to evaluate the designs. A design is selected to have the minimum information content. The significance of this research is that a full cycle of axiomatic design is applied to a real engineering product.