• Proceedings of the Korean Society of Medical Physics Conference
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• 2003.09a
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• pp.48-48
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• 2003

Abstract: 현대 질병의 최종진단은 세포수준의 해부형태학적 연구가 일반적이며 광학현미경이나 전자현미경을 이용한 병리조직학적 소견을 바탕으로 진단되어지고 있다. 이러한 진단에는 In vivo 검사가 거의 불가능하여 주로 생검을 통한 연구만 수행되고 있어 진단함에 있어 단계적인 불편이 초래될 뿐만 아니라 악성 종양의 전이를 유발시킬 수 있고 또한 생리 및 생화학적 분석이 어렵다. 이러한 문제점을 해결하기 위해 고분해능의 RF Surface Coil을 개발하여 In vivo 및 비침습적인 방법인 MR Technology를 이용하고자 한다. Introduction: 피부조직과 같은 미세 인체구조 연구를 위해 고해상도 3T MRI 시스템에 적합한 고분해능의 RF surface coil을 개발하고 있다. In vivo 연구를 위한 여러 parameter를 최적화하여 기능영상에도 부합된다. 비침습적인 In vivo 검사에 의한 세포수준의 극 미세구조의 연구가 가능해짐으로써 과거 시행하던 침습적인 생검없이 각종질환의 진단적 접근이 병리학적 수준으로 향상되어 질병의 정확한 진단이 가능해지게 될 것이다. Method: 고분해능의 RF Surface Coil을 제작하여 3T MR 장비에서 피부 미세구조연구에 보다 적합하도록 In vivo 및 In vitro 실험을 수행하였다. In vitro 실험은 In vivo 연구를 위한 여러 parameter들을 최적화하기 위한 기초 실험을 하였고 다양한 팬톰들을 이용하여 Tl 강조영상, T2 강조영상을 획득하였으며, SNR을 높이기 위한 개선에 대한 연구를 수행하였다. In vivo 실험은 정상피부에서 다양한 부위에 대한 피부영상의 예비 연구를 수행하였다. Result and Discussion: 비침습적인 In vivo 검사에 의한 세포수준의 극 미세구조의 연구가 가능해짐으로써 과거 시행하던 침습적인 생검없이 각종질환의 진단적 접근이 병리학적 수준에서 가능해짐으로써 질병의 정확한 진단이 가능해지게 될 것이다. Acknowledgement: 본 연구는 2002 년도 한국과학재단 목적기초연구사업 (과제번호 : R0l-2002-000-00294-0 (2002)) 지원아래 수행되었다.

• Journal of Satellite, Information and Communications
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• v.1 no.2
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• pp.25-31
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• 2006

The COMS (Communication, Ocean, and Meteorological Satellite) performing meteorological and ocean monitoring and providing communication service with meteorological, ocean and Ka-band payload in the geostationary orbit includes MODCS (Meteorological and Ocean Data Communication Subsystem) which provides transmitting the raw data collected by meteorological payload called MI (Meteorological Imager) and ocean payload named GOCI (Geostationary Ocean Color Imager) to the ground station and relaying the meteorological data processed on the ground to the end-user stations. MODCS comprises of two channels: SD channel which formats the raw data according to CCSDS recommendation, amplifies and transmits its signal to the ground station; MPDR channel which relays to the end-user stations the ground-processed meteorological data in the data format of LRIT/HRIT recommended by CGMS. This paper constructs the architecture of MODCS for transmitting and relating the observed data, and investigates that the key performance parameters have the required margin through the preliminary performance analyses.

• Journal of Navigation and Port Research
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• v.30 no.6 s.112
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• pp.525-531
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• 2006

In the port, the yard crane is very important. If a container crane or a transfer crane is broken down, it costs a lot because of the delay of work during the period of repair or reorder. But, we don't have enough spare parts because of the high cost. It is necessary to maintain high reliability of the crane through effective preventive maintenance and failure analysis. In this paper, we analyse the function and failure mechanism of the transfer crane which is a main equipment in the yard Also, we standardize failures and maintenance works using the historical data of failure and maintenance. This study which is a basic work for effective equipment operation and maintenance will support reliability engineers to decide the optimal design of the next generation equipment and operational policy of equipment.

• Journal of The Korean Association For Science Education
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• v.32 no.2
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• pp.210-235
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• 2012

The purpose of this study was to develop a valid and reliable assessment tool for measuring scientific creative problem solving ability for middle school students. To achieve this aim, an assessment framework, four assessment items, and detailed rubrics for scientific creative problem solving were developed. The assessment framework had three dimensions (i.e. science contents, inquiry process, and thinking skills) and sub-elements for each dimension. The assessment items were tested with 320 middle school students in order to determine reliability, difficulty, and item discrimination. Science teachers and experts in science education checked the validity of the items and the rubrics. The results proved that the assessment tool was reliable enough to evaluate students' scientific creative problem solving skills.

• School Mathematics
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• v.12 no.4
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• pp.585-604
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• 2010

This study aims to investigate understanding of meanings of division, quotitive division and partitive division, by the third graders and preservice elementary teachers. To do this, we analysed and compared mathematics textbooks according to 9 mathematics curricula, gathered information about their understanding by questionnaire method targeting 5 third graders and 36 preservice elementary teachers, and analysed their responses in relation to recognition of division-based situations, solution using visual representations, and awareness of quotitive division and partitive division. In Korea, meanings of division have been taught in grade 2 or 3 in various ways according to curricula. In particular, the mathematics textbook of present curriculum shows a couple of radical changes in relation to introduction of division. We raised the necessity of reexamination of these changes, based on our results from questionnaire analysis that show lack of understanding about two meanings of division by the preservice elementary teachers as well as the third graders. And we also induced several didactical implications for teaching meanings of division.

• The KIPS Transactions:PartA
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• v.16A no.4
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• pp.235-244
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• 2009

The mission-critical computer for air defense has to maintain its operation without any fault for a long mission time and is required to implement at low cost. Now the reliability of the mission critical-computer using Active Sparing Redundancy fault-tolerant technique is inferior to that of the computer using TMR technique. So in this paper are proposed Extended ASR(EASR) technique that provides higher reliability than that of the computer using TMR technique. The fault-tolerant performance of the implemented mission-critical computer is proven through reliability analysis and numbers of fault recovery test. Also, the reliability of the mission-critical computer using EASR technique is compared with those of computer using ASR and TMR techniques. EASR technique is very suitable to the mission-critical computer.

• Journal of the Society of Naval Architects of Korea
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• v.36 no.4
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• pp.105-115
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• 1999

To develope the best optimized hull form, it has been generalized to evaluate the preliminary hull forms with the CFD tools in the initial stage of development and for this process it is needed to prepare various competent hull forms with high degree of fairness. In this paper, a modified shape variation method was developed to maintain the shape and fairness of parent hull form and the automatic update procedure was implemented on the basis of the association concept. It was shown that the hull form of the high quality in fairness and shape inherited from the parent hull form can be archived.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.2
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• pp.445-451
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• 2014

Dual LED lantern, which is composed of two light sources in one lantern, can be utilized as an auxiliary light source when the main light source is in trouble. Nevertheless, there are no way to obtain status information of the system and control the light source if the current domestic standard protocol is applied, since the standards for dual LED lantern are not defined yet. Regarding to this problem, we suggested expanded lantern protocol for management system of dual LED lantern based on current domestic standard. Also, we confirmed the normal operation of dual LED lantern after implementing suggested protocol on the developed management system. Control system suggested and implemented in this study is tested not only its function of controlling and acquiring the operating status of dual LED lantern, but also its capability to utilize as a control system of currently used LED lanterns.

• The Journal of the Acoustical Society of Korea
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• v.41 no.1
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• pp.45-51
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• 2022

Sound quality evaluation is one of the psychoacoustic methods to measure subjective judgements for sound color. The purpose of this study is to investigate sound quality benefits of bimodal users by comparing sound quality scores between bimodal hearing condition and unilateral cochlear implant(CI) condition as a preliminary study. Thirteen bimodal users and seven unilateral CI users were participated in this study. Audiologists performed pure tone and speech audiometry and measured functional gain and real-ear insertion gain. Subjective assessment of sound quality was followed with four sounds including violin sound, male and female voices, and refrigerator noise. Participants judged the sound quality with six sound quality index. Bimodal users showed mean 0.8 points more sound quality improvements in bimodal condition than unilateral CI condition. Group comparison between bimodal and unilateral CI users showed no differences. A follow-up study of sound quality tools and methods should be considered to evaluate subjective bimodal benefits of cochlear implant users.

• Journal of Digital Convergence
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• v.18 no.7
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• pp.215-222
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• 2020

The aim of this study was to develop a mobile application 'Beat Processing Device (BPD)' to record and quantify the data for the performance accuracy of rhythm production. BPD has been developed in three phases. First, we reviewed studies that used rhythm as main intervention strategy to improve cognitive functioning of older adults, and derived four basic rhythm idioms. Second, we developed an iOS-based mobile application, optimized the device, the instrument tone, and the measurement variables through preliminary test. Lastly, we tested the mobile application by comparing the performance data obtained from MIDI and BPD from 60 older adults. The device was shown to be reliable and consistent with other mode of measurement and analysis. Conclusively, BPD can be a useful tool for assessing rhythm production ability in the course of cognitive skills training.