• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.10
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• pp.648-654
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• 2018

In order to maintain manholes installed on the road, the manhole should be easy to open and close. Manhole covers under harsh conditions require that they can be lifted when attempting to open the manhole because the frame and cover are stuck and difficult to open and close. In this study, the design of a lifting mechanism was carried out to improve and integrate the locking type manhole. The mechanism of the locking manhole is that when the bolt located at the center is turned, the hub connected with the bolt descends, and the hook connected to the hub is rotated. The end of the hook is hooked to the manhole frame. The auxiliary device was installed on the hook so that the manhole cover can be lifted. The structure was designed to endure about 300kg of lifting force based on 70% of the yield stress of the hook to perform lifting function. The shape design was performed through the structural analysis using the finite element method. First, the basic design was performed with the simplified 2-dimensional model and the attachment position and shape were designed through the 3-dimensional model. In order to find out the structural problems of the designed shape, the scale downed model was fabricated through 3D printing and confirmed that the lifting function worked. Finally, it was confirmed that both the locking and the average lifting of about 6.1 mm can be done by applying the lifting mechanism through the machining and applying it to the existing locking manhole.

• Journal of KIISE
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• v.44 no.4
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• pp.374-382
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• 2017

As the walking exercise is emphasized in personalized healthcare, numerous services demand walking information. Along with the propagation of smartphones nowadays, many step-counter applications have been released. But these applications are error-prone to abnormal movements such as simple shaking or vibrations; also, different step counts are shown when the phone is positioned in different locations of the body. In this paper, the proposed method accurately counts the steps regardless of the smartphone position by using an accelerometer and a proximity sensor. A threshold is set on each of the six positions to minimize the error of undetection and over-detection, and the cut-off section is set to eliminate any noise. The test results show that the six position type were successfully identified, and through a comparison experiment with the existing application, the proposed technique was verified as superior in terms of accuracy.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.4
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• pp.569-574
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• 2013

With probably too many smart phone applications downloaded, it is sometimes frustrating to find frequently used applications quickly. In this paper, we propose a learning application that learns what applications a user frequently uses and match them with several signals that user designated. This learning applications uses ART2 algorithm that is good for stable real-time learning. By executing this learning application, a user simply chooses an application that is to be quickly searched and then draw a figure that would match the designated application at the upper left corner of our learning application. The proposed learning application transforms the background with 0's and the figure with 1's and normalize them to be used as inputs for ART2 and ART2 does clustering to setup a match table between applications and figures. After learning, a user simply draws a figure to execute one's frequently used application.

• Composites Research
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• v.25 no.6
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• pp.236-240
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• 2012

The purpose of this study was to investigate the feasibility on the detection of dental composite delamination using a lock-in thermography method. Amplitude and phase images of detected thermal signals were analyzed according to the lock-in frequencies. At a lock-in frequency of 0.05 Hz, the ligament thickness of 0.5 mm in the specimen exhibited the highest amplitude contrast between defective area and sound area. For ligament thicknesses of 1 mm and 1.5 mm, delamination detection was possible at 0.025 Hz and 0.01 Hz through the amplitude differences. At lock-in frequencies of 0.006 Hz and 0.01 Hz, ligament thickness 0.5 mm exhibited the highest phase contrast. For ligament thicknesses of 1 mm and 1.5 mm, the phase contrast exhibited possible detection of delamination at 0.006-0.1 Hz.

• Proceedings of the KAIS Fall Conference
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• 2010.11a
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• pp.50-53
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• 2010

늘어나는 물동량으로 인해 화물 운송의 중요성은 커지고 있으며 그와 더불어 화물 운송 중 발생하는 도난 또는 분실 사고도 빈번히 발생하고 있다. 고가 화물의 경우 운송 도중 사고가 발생하게 되면 일반 화물에 비해 그 피해정도는 훨씬 심각하다. 그러나 대부분 고가 화물의 운송 중 발생하는 사고에 대한 대책은 운송 보험 가입을 통해 도난 및 분실 피해에 대한 보상에만 초점이 맞춰져 있는 상황이다. 이에 본 연구에서는 새로운 기술인 IP-RFID를 이용하여 운송 중인 고가 화물의 상태 정보 및 위치 정보 파악과 화물 운송함 잠금장치 제어를 통해 고가 화물의 도난을 사전에 방지하고 안전하게 운송 할 수 있는 방안을 제시한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2017.11a
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• pp.510-513
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• 2017

자전거 이용자 급증으로 자전거의 도난 및 분실을 방지하여 사용자를 안심시켜주고 주행 중 위험요소를 줄이고자 하는 목소리가 높아지고 있다. 본 논문에서는 애플리케이션 개발을 위해 MCU(Micro Controller Unit)인 Arduino Mega 2560 기반에 블루투스(Bluetooth) 통신 방식을 사용하여 자전거 잠금장치, 위치 추적 장치를 조작하고 후방 감지 장치를 제어하였으며 초음파 거리센서 값을 이용하여 LED Strip 및 진동 모터로 사용자에게 주행 상태를 알리는 장치를 구현하였다.

• Proceedings of the Korean Information Science Society Conference
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• 2001.04a
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• pp.196-198
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• 2001

최근 Outlook Express나 유도라와 같은 메일 프로그램이 웹 브라우저를 이용하여 메일을 송수신 할 수 있는 웹 메일 서비스가 제공되면서 점진적으로 기존의 메일 서비스를 대체하고 있다. 기존 메일 시스템은 메시지 전송 에이전트(sendmail)의 보안상 허점 및 파일 잠금 현상, CGI방식의 과도한 오버헤드, POP3 프로토콜의 위치 투명성 지원 미비 등 여러 가지 문제점을 내포하고 있다. 본 논문에서는 기존 메일 시스템의 문제점을 해결하기 위해서 PHP와 큐 메일, IMAP 프로토콜을 사용한 3-티어 구조의 웹 메일 시스템을 설계하고 구현하였다. 구현된 시스템은 강화된 보안 기능과 안전한 메시지 수신을 보장하며 부하 분산을 통해 서버의 효율이 향상되었다.

• Convergence Security Journal
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• v.16 no.2
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• pp.71-76
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• 2016

As an extreme-type crime caused by social anxiety and economic hardship, firearm accidents recently rising as a serious social problem are gradually increasing the national anxiety as people start realizing that Korea is no more a safety zone for firearm accidents. In order to improve it, the police and academia are presenting measures through the suggestion of diverse policies and also change of system. However, there are not sufficient researches in the aspect of technology while some people argue that they cannot become fundamental alternatives on top of its effectiveness issue. Thus, this study has suggested a more effective firearms safety control system in the aspect of technology.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.11
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• pp.4738-4744
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• 2011

This study proposes the system of new small sluice gate operated without the upper concrete structure. The new mechanism is composed of hydraulic system, driving mechanism to feed the floodgate up and down, hydrological locking device, safety device and etc. The hydraulic pumps and control systems away from the location of the sluice gate systems are installed and controled in place. The feed device with the hydraulic rack, pinion and hydraulic actuator is installed on the side of the sluice gate. The following results take the advantages of cost reduction, operation safety and compact product.

• Journal of the Korean Society for Nondestructive Testing
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• v.32 no.2
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• pp.162-169
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• 2012

This study detected SCC defects of dissimilar metal welded(STS304 and SA106 Gr. b) pipes using the ultrasonic infrared thermography method and the lock-in image treatment method among infrared thermography method. The infrared excitement equipment has 250 Watt of output and 20 kHz of frequency. By using the ultrasound infrared thermography method, the internal defects of dissimilar metal weld joints of pipes used at nuclear power plants could get detected. By an actual PT test, it was observed that the cracks inside the pipe existed not as a single crack but rather as a multiple cracks within a certain area and generated a hot spot image of a broad area on the thermography image. In addition, UT technology could not easily defects detected by the width of $10\;{\mu}m$ fine hair cracks. but, ultrasound infrared thermography technique was defect detected.