• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.351-351
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• 2011

Graphene has drawn great interests because of its distinctive band structure and physical properties[1]. A few of the practical applications envisioned for graphene include semiconductor applications, optoelectronics (sola cell, touch screens, liquid crystal displays), and graphene based batteries/super-capacitors [2-3]. Recent work has shown that excellent electronic properties are exhibited by large-scale ultrathin graphite films, grown by chemical vapor deposition on a polycrystalline metal and transferred to a device-compatible surface[4]. In this paper, we focussed our scope for the understanding the graphene growth at different conditions, which enables to control the growth towards the application aimed. The graphene was grown using chemical vapor deposition (CVD) with methane and hydrogen gas in vacuum furnace system. The grown graphene was characterized using a scanning electron microscope(SEM) and Raman spectroscopy. We changed the growth temperature from 900 to $1050^{\circ}C$ with various gas flow rate and composition rate. The growth condition for larger domain will be discussed.

• Convergence Security Journal
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• v.13 no.2
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• pp.95-100
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• 2013

As the near field communication technology's application scope tends to expand gradually in the various fields, application of mobile-based NFC(Near Field Communication) is increasing in the various types of technologies. The method which reads the URL address and supports access to the web site of the address if you touch the NFC device in the tag(RFID) that the URL address is stored was applied to the unmanned security system. It proposed the effective plan to manage mobilization security business in the aspects of Integrity, Damage, Real-Time, and Speed through comparison and verification of the method with the existing unmanned security system.

• International Journal of Precision Engineering and Manufacturing
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• v.9 no.4
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• pp.16-21
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• 2008

The demand for three-dimensional (3D) shape measurements is increasing in a variety of fields, including the manufacture of molds and dies. The most popular technology for 3D shape measurement is the coordinate measuring machine (CMM) with a contact trigger probe. Although a CMM provides a high degree of accuracy, it is inefficient due to its long measuring time. It also has difficulty measuring soft objects that can be deformed by the touch of the contact probe. In addition, a CMM cannot digitize areas that are difficult to reach, and cannot capture very minute details on the surface of complex parts. For these reasons, optical non-contact measurement techniques are receiving more attention since they eliminate most of the problems associated with contact methods. Laser scanning is emerging as one of the more promising non-contact measurement techniques. This paper describes various acquisition considerations for laser scanning, including the accuracy of the 3D scan data, which depends on the charge-coupled device (CCD) gain and noise. The CCD gain and noise of a 3D laser scanner are varied while keeping the other conditions constant, and the measurement results are compared to the dimensions of a standard model. The experimental results show that a considerable time savings and an optimum degree of accuracy are possible by selecting the proper CCD gain and noise.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.159-159
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• 2008

Indium-tin oxides (ITO) films have been widely used as transparent electrodes for optoelectronic devices such as organic light emitting diodes (OLEDs), photovoltaics, touch screen devices, and flat-paneldisplay. In particular, to improve hole injection efficiency in OLEDs, transparent electrodes should have high work-function besides their transparency and low resistivity. Nevertheless, few studies have been made on engineering the work function of ITO for use as an efficient anode. In this study, the effects of a wide range of Nb or Zn doping rate on the changes in work functions of ITO anode were investigated. The Nb or Zn doped ITO films were fabricated on glass substrates using combinatorial sputtering system which yields a linear composition spread of Nb or Zn concentration in ITO films in a controlled manner by co-sputtering two targets of ITO and Nb2O5 or ITO and ZnO. We have also examined the resistivity, transmittance, and other structural properties of the Nb or Zn-doped ITO films. Furthermore, OLEDs employing Nb or Zn-doped ITO anodes were fabricated and the device performances were investigated concerned with the work function changes.

• The Journal of Information Systems
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• v.21 no.4
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• pp.81-108
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• 2012

Growth in the device field is driven by various emerging devices, tablet PC are among the most recognizable. Tablet PC are mobile computing devices enabled with touch screens or pen inputs and provide the functions of various other devices. Firms are interested in utilization of tablet PC on task. Many of firms is considering accepting of tablet PC and is looking forward to performance of tablet PC. Thus, this study propose to discuss strategies for the usage of tablet PC from organizational needs perspective. The goal of this study is to identify factors influencing use of tablet PC and task performance. The results of this study showed that the proposed factors of organizational needs with a exception of Service Flexibility had a positive impact on perceived usefulness that then positively affected Usage of Tablet PC and Task Performance. In addition, perceived task-technology fit had a positive impact on perceived usefulness and Usage of Tablet PC. Finally, Innovative Culture of Organization as a moderating effect significantly influenced the relationship between perceived usefulness, perceived Task-Technology Fit and Usage of Tablet PC. This study is expected to be a reference for a subsequent study associated with Tablet PC at organizational viewpoints.

• Design & Manufacturing
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• v.11 no.2
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• pp.42-45
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• 2017

Currently, the mobile device is required to be miniaturized and lightweight according to the needs of the consumer. For this purpose, each part is produced and assembled in units of modules. Accordingly, the display part is also composed of a cover glass, a touch screen, And it costs a large amount to replace the whole when it is damaged. Therefore, we propose a method to improve the durability of display part using ANOVA (Analysis of Variance) and MR fluid polishing. Before MR fluid polishing process, surface treatment was performed to obtain a polishable surface. A series of experiments were carried out to very fine surface roughness and to secure durability of cover glass. Polishing depth, feed rate, and abrasive size were selected to examine the MR fluid polishing results.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.49-49
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• 2010

Nanopiezotronics is an emerging area of nanotechnology with a variety of applications that include piezoelectric field-effect transistors and diodes, self-powered nanogenerators and biosystems, and wireless nano/biosensors. By exploiting coupled piezoelectric and semiconducting characteristics, it is possible for nanowires, nanobelts, or nanorods to generate rectifying current and potential under external mechanical energies such as body movement (handling, winding, pushing, and bending) and muscle stretching, vibrations (acoustic and ultrasonic waves), and hydraulic forces (body fluid and blood flow). Fully transparent, flexible (TF) nanogenerators that are operated by external mechanical forces will be presented. By controlling the density of the seed layer for ZnO nanorod growth, transparent ZnO nanorod arrays were grown on ITO/PES films, and a TF conductive electrode was stacked on the ZnO nanorods. The resulting integrated TF nanodevice (having transparency exceeding 70 %) generated a noticeable current when it was pushed by application of an external load. The output current density was clearly dependent on the force applied. Furthermore, the output current density depended strongly on the morphology and the work function of the top electrode. ZnO nanorod-based nanogenerators with a PdAu, ITO, CNT, and graphene top electrodes gave output current densities of approximately $1-10\;uA/cm^2$ at a load of 0.9 kgf. Our results suggest that our TF nanogenerators are suitable for self-powered TF device applications such as flexible self-powered touch sensors, wearable artificial skins, fully rollable display mobile devices, and battery supplements for wearable cellular phones.

• Journal of Korea Multimedia Society
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• v.17 no.5
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• pp.613-622
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• 2014

In spite of the convenience and cost-effectiveness of an electronic document management system the paper-type documents still should be stored for a comparison against the original documents. In this paper, for the efficient management of paper documents, we designed and implemented a document management system using smart devices equipped with NFC(Near Field Communication) technology. To implement the proposed system we designed a database for document management and developed an Android application for smart device using Eclipse 3.0 and Java programming. Whenever we touch the smart phone on the NFC tags which are attached to the paper-type documents and document boxes, it is possible to registering, searching and carrying in and out services for documents and boxes. This study provides smart phone users with systematic, economical and convenient paper-type documents management functions, and thus enhances the business efficiency.

• Proceedings of the Korea Information Processing Society Conference
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• 2015.04a
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• pp.1061-1064
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• 2015

본 논문은 근전도 센서가 탑재된 손목착용형 웨어러블 디바이스를 통하여 스마트폰의 입력방식을 개선시켜 사용자와 스마트폰간의 인터렉션을 보다 발전시킨 시스템을 다룬다. 이 시스템은 사용자가 손목에 착용한 웨어러블 디바이스에 탑재된 근전도센서를 통하여 손의 고유근의 근전도를 측정함으로서 사용자의 엄지와 검지에 가해지는 힘을 탐지하고 이를 바탕으로 사용자가 스마트폰을 터치했을 경우 해당 터치행위가 사용자가 스마트폰을 의도적으로 힘을 가하여 누른 행위인지에 대한 여부를 판단할 수 있다. 결과적으로 본 논문은 스마트폰과 사용자와의 인터렉션에 있어 근전도 센서를 탑재한 웨어러블 디바이스를 활용하여 사용자의 의도를 보다 효과적으로 스마트폰 제어에 반영시킬 수 있는 행위 인지(Activity Recognition) 터치 인터페이스 시스템을 제안한다.

• KIPS Transactions on Computer and Communication Systems
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• v.2 no.12
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• pp.525-532
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• 2013

Recently smartphones, tablet, etc. Various types of smart terminal is due to the increased security in mobile devices are becoming an issue. How to enter the password in this environment is a very important issue. Difficult to have a secure password input device on various types of mobile devices. In addition you enter on the touch screen the password of character, uncomfortable and it is vulnerable to SSA attack. Therefore, in this paper provide for defense the SSA(Shoulder Surfing Attacks) and useful password input mechanism is proposed with Smartphone GPS uses a value generated via a graphical password techniques.