• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2002년도 International Meeting on Information Display
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• pp.325-328
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• 2002

We developed a high performance 2.2" active matrix OLED display for IMT-2000 mobile phone. Scan and Data driver circuits were integrated on the glass substrate, using low temperature poly-Si(LTPS) TFT CMOS technology. High efficiency EL materials were employed to the panel for low power consumption. Peak luminescence of the panel was higher than 250cd/$m^2$ with power consumption of 200mW.

• 한국기계가공학회지
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• 제14권2호
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• pp.81-86
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• 2015

This study investigated electromagnetic interference (EMI) shielding effectiveness (SE) of hybrid conductive fabrics. The coaxial transmission line method was used to measure the EMI Shielding effectiveness of the conductive fabrics. We designed and constructed a measuring system, consisting of a network analyzer and a device that serves as a sample holder and at the same time as a transmission medium of incident electromagnetic waves. The measurements of SE were carried out in a frequency range from 100 MHz to 2 GHz. The results of the EMI shielding experiments showed that the maximum electromagnetic shielding effectiveness (EMSE) values of sandwich type C/A/C (carbon fiber sheet/aluminum foil tape/carbon fiber sheet) and C/Ni/C (carbon fiber sheet/magnetic shielding foil/carbon fiber sheet) samples were 55 dB and 113 dB, respectively, at a frequency of 1.9 GHz.

• Educational Technology International
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• 제7권1호
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• pp.1-20
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• 2006

This paper describes practical research on the improvement of teaching and learning process by integrating Web Bulletin Board (WBB) and mobile phone. This paper addresses three topics; A) the interactive lecture with topics-based discussions using the Web Bulletin Board (WBB) as a tool for assisting discussion, B) the introduction of peer evaluation among students to develop their problem-solving and cognitive skills, C) the use of mobile phones for promoting interactive lectures, keeping class attendance, conducting assignments, and providing notices for the next class. Results indicated the following research-findings: (1) WBB plays a role in facilitating positive participation in classes. (2) In contrast to the scenario of the traditional mode of instruction (without the usage of WBB), students were able to deepen their understanding of the theme by accessing the WBB before and after classes. (3) Peer evaluation highly promoted students' motivation to learn, and was effective in cultivating meta-cognition through modeling. (4) Mobile phone was identified as a highly effective tool for keeping class attendance, realizing interactive classes by generating discussions, and managing assignments and homework.

• KIEE International Transactions on Electrophysics and Applications
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• 제5C권4호
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• pp.176-179
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• 2005

The increasing demand for high density packaging technologies and the evolution to mixed digital and analogue devices has been the con-set of increasing research in thin film multi-layer technologies such as the passive components integration technology. In this paper, Cu and TaO thin film with RF sputtering was deposited for spiral inductor and MOM capacitor on the $SiO_2$/Si(100) substrate. MOM capacitor and spiral inductor were fabricated for L-C band pass filter by sputtering and lift-off. We are analyzed and designed thin films L-C passive components for band pass filter at 900 MHz and 1.8 GHz, important devices for mobile communication system. Based on the high-Q values of passive components, MOM capacitor and spiral inductors for L-C band pass filter, a low insertion loss of L-C passive components can be realized with a minimized chip area. The insertion loss was 3 dB for a 1.8 GHz filter, and 5 dB for a 900 MHz filter. This paper also discusses a analysis and practical design to thin-film L-C band pass filter.

• 대한정형도수물리치료학회지
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• 제18권2호
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• pp.95-102
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• 2012

Background: The purpose of this study was to find out influence of using portable mobile devices in human body. Method: The subjects were consisted of the normal persons (19 males and 20 females). These subjects were consisted of three groups according to test time. The A group (12 persons - 6 males, 6 females) tests 5 minutes, the B group (14 persons - 7 males, 7 females) tests 10 minutes, and the C group (13 persons - 6 males, 7 females) tests 15 minutes. Before test, sight, quickness and balance were measured, after test revision, quickness, balance were measured and checked pain scale. Results: The results were as follows. 1. Sight, quickness and balance were decreased and pains were increased after using portable mobile devices than before using these. 2. According to duration of using the portable mobile devices, sight, quickness and balance was not a statistically significant difference, the entire upper body pain was a statistically significant difference. When viewed as part of the pain, shoulder, lower back, and wrist pain were a statistically significant difference, but the neck and elbow were not a statistically significant difference. 3. The influence of vision according to distance of using Portable mobile devices was no statistically significant difference. In addition, less than 20cm distance using equipment group ("Ga") and the group ("Na") which exceeded 20cm in between the sight were not statistically significant difference, Influence of pain according to distance of using Portable mobile devices we-re no statistically significant differences. Conclusion: Using portable mobile devices affect human body on the elements of the biomechanics.

• Management Science and Financial Engineering
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• 제11권3호
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• pp.1-17
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• 2005

Agent technology has been widely applied in today's electronic business, such as mobile agents, multi-agent information systems, etc. In particular, multi-agent systems have been applied as powerful simulation tools to study complex business networks composed of various self-interested trading firms and/or human beings. In this paper, we build an integrated model that consists of a multi-agent B2C market model and a B2B trade network model, and incorporate more reality than much of prior work. Then with this model, we carry out experimental studies on two different strategies that are common in electronic business - 'loyal' strategy (retailers try to build stable cooperation with suppiers to ensure material supply) and 'cost-saving' strategy (retailers try to reduce cost by choosing suppliers with lower wholesale price).

• 전자통신동향분석
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• 제28권2호
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• pp.38-49
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• 2013

본고에서는 무선랜 기반 근접인식(proximity awareness) 모바일 서비스 제공에 필요한 관련 기술 동향 및 표준현황을 정리한다. 특히 수많은 기기들이 산재하는 모바일 D2D(Device to Device) 통신환경에서 인접 장치 및 서비스 발견 과정에 사용자 개입을 최소화할 수 있도록 접속 대상을 보고 선택하는 방식의 시선통신(look-and-link)과 네트워크 계층의 접속 이전에 주변 디바이스에서 제공되는 서비스를 미리 파악하거나 간단한 정보를 송수신할 수 있는 무결합 메시징(preassociation messaging) 연구동향을 소개한다. 이러한 기술은 셀룰러 중심의 기존 모바일 서비스들과 차별성을 가지며 무선랜 기술을 활용하는 D2D 환경에서 근접인식 모바일 서비스를 활성화할 수 있는 핵심 요소기술로 이용될 것이다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제17권2호
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• pp.626-643
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• 2023

As mobile forensics has emerged as an essential technique, the demand for technology development, education and training is increasing, wherein images are used. Academic societies in South Korea and national institutions in the US and the UK are leading the Mobile Forensic Image development. However, compared with disks, images developed in a mobile environment are few cases and have less active research, causing a waste of time, money, and manpower. Mobile Forensic Images are also difficult to trust owing to insufficient verification processes. Additionally, in South Korea, there are legal issues involving the Telecommunications Business Act and the Act on the Protection and Use of Location Information. Therefore, in this study, we requested a review of a standard model for the development of Mobile Forensic Image from experts and designed an 11-step development model. The steps of the model are as follows: a. setting of design directions, b. scenario design, c. selection of analysis techniques, d. review of legal issues, e. creation of virtual information, f. configuring system settings, g. performing imaging as per scenarios, h. Developing a checklist, i. internal verification, j. external verification, and k. confirmation of validity. Finally, we identified the differences between the mobile and disk environments and discussed the institutional efforts of South Korea. This study will also provide a guideline for the development of professional quality verification and proficiency tests as well as technology and talent-nurturing tools. We propose a method that can be used as a guide to secure pan-national trust in forensic examiners and tools. We expect this study to strengthen the mobile forensics capabilities of forensic examiners and researchers. This research will be used for the verification and evaluation of individuals and institutions, contributing to national security, eventually.

• 한국콘텐츠학회논문지
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• 제17권11호
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• pp.143-155
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• 2017

모바일 우선주의 시대에 수많은 모바일 앱이 쏟아지면서 사용자들이 보유하는 앱의 숫자도 증가하게 되었다. 그러나 실제로 자주 사용하는 앱의 숫자는 적고 많은 앱들이 언젠가 사용되기 위해 보관되고 있다. 이런 앱들을 사용자가 필요한 순간에 스마트폰에서 빠르게 찾도록 하기 위해서는 사용자들이 앱아이콘을 어떻게 관리하고 어떻게 탐색하는지에 대한 연구가 필요가 있다. 본 연구는 문헌연구에서 앱아이콘 정리, 앱아이콘 인지 및 디자인의 변화에 대해서 고찰하고 5가지 정리 유형(사용빈도, 유사성, 사용성, 심미성, 외부영향)을 추출하였다. 이를 토대로 30명의 아이폰 사용자들의 모바일 화면을 관찰 분석하여 유사성, 심미성, 외부의 영향을 3가지 주요 유형으로 확정하여 사용자 유형을 나누고, 각 사용자마다 자신의 폰에서 앱아이콘을 찾는 실험을 진행하여 사용자 유형별 아이콘 탐색 시간의 차이를 검증하였다. 자주 사용하는 앱의 경우는 대부분의 피험자들이 2초 이하로 빨리 찾았지만 자주 사용하지 않는 앱의 경우에는 유사성을 중심으로 정리하는 사용자가 평균 6초로 가장 빨리 찾았고 심미성을 고려해서 정리한 사용자가 평균 19초로 가장 오래 걸렸다. 또한, 사용자 유형별 인터뷰 결과 유사성 중심으로 정리하는 사용자에게는 앱아이콘 보다는 앱 이름의 기능 유추 여부가 중요하며, 심미성을 고려하여 정리하는 사용자에게는 앱아이콘의 칼라가 중요하고, 폴더 사용 없이 폰에서 제공하는 순서대로 앱을 배치하는 사용자들에게는 수많은 앱 아이콘들 사이에서 빠르게 시선을 잡아줄 수 있는 앱아이콘의 가시성이 중요함을 알 수 있었다. 본 연구의 결과는 사용자들의 성향을 고려하면서 앱 아이콘의 사용성을 높이기 위한 디자인을 하는데 기초자료로 활용될 수 있을 것으로 기대된다.

• Natural Product Sciences
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• 제15권3호
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• pp.144-150
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• 2009

Gradient centrifugal partition chromatography (GCPC) method was developed and applied to isolate 3,5-dimethoxyphenanthrene-2,7-diol (DMP) and batatasin-I (BA-I) from the dichloromethane soluble extract of Dioscorea opposita. In this method, the lower phase of n-hexane-methanol-water system (HMW, 10 : 9 : 1, v/v) was used as a mobile phase A (MpA) and water was used as a mobile phase B (MpB). This gradient CPC method is comparable to that of reversed-phase HPLC method in that the stationary upper-phase of HMW (10 : 9 : 1 v/v) works as if it were reversed-phase silica gel due to its hydrophobic property, while the lower phase (MpA) and water (MpB) functioned as hydrophilic mobile phases. The initial condition of the mobile phase was 20% MpA/80% MpB and maintained for 150 min to obtain DMP (1.2 mg), and then MpA was increased up to 50% to elute BA-I (1.7 mg). The purities of DMP and BA-I were 94.1% and 98.3% with the recovery yields of 83% and 86%, respectively. Similar results were obtained by linear-gradient CPC. The CPC peak fractions were identified by comparing their retention time to those of authentic samples of DMP and BA-I and their spectroscopic data ($^1$H NMR and $^{13}$C NMR) to those of literature values.