• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2002.11a
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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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• v.13 no.1
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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.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.23 no.5
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• pp.218-223
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• 2013

In this study, the reflectivity characteristics of Ag nano-coating grown by electroless plating were investigated in order to use as the reflecting plate of BLU (Back Light Unit) in the LCD (Liquid Crystal Display) or LED (Light Emitting Diode) display equipment. The microstructure of Ag nano-coating was polycrystalline nano-structure that consisted of Ag nano-crystals to be reduced and precipitated, and the size of reduced nano-crystals increased as the thickness of nano-coating increased. The reflectivity of Ag nano-coating in the visible light decreased as the thickness of nano-coating increased and the reduction of reflectivity was more severe in the short wavelength region of visible light. The decrease of reflectivity was closely related to the size of Ag nano-crystal and was thought to be due to the larger surface roughness of larger nano-coating thickness. Therefore, the finer Ag nano-crystals and thinner nano-coating thickness could be favorable for the higher reflectivity of Ag nano-coating grown by electroless plating.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.1
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• pp.23-30
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• 2014

Recently, Light Emitting Diode(LED) light is changing the light equipment, which was considered just as a power-controlled device in home-network, into a IT convergence device by combining illumination function with wireless communication. As a result, Visible Light Communication(VLC) becomes a more practical solution to ubiquitous networks due to the more spread of LED light. One of representative applications using VLC is a VLC-based indoor navigation system which can provide high-accuracy indoor localization. In this paper, we model and implement a VLC based-indoor navigation system in which a fluorescent light type of LED lamp, which is normally used in large buildings, and smart devices, which are usually used by users, are utilized as main components for indoor navigation. Subsequently, it is expected that the paper can contribute to make VLC applications be more active.

• Journal of Information Technology Applications and Management
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• v.26 no.6
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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.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.04a
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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.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.27 no.5
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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.

• Korean Institute of Interior Design Journal
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• no.1
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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.

• Journal of Sensor Science and Technology
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• v.27 no.5
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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.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.9
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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.