• Journal of Biomedical Engineering Research
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• v.25 no.4
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• pp.269-275
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• 2004

Different biological tissues have different values of electrical resistivity. In EIT (electrical impedance tomography), we try to provide cross-sectional images of a resistivity distribution inside an electrically conducting subject such as the human body mainly for functional imaging. However, it is well known that the image reconstruction problem in EIT is ill-posed and the quality of a reconstructed image highly depends on the measurement error. This requires us to develop a high-performance EIT system. In this paper, we describe the development of a 16-channel digital EIT system including a single constant current source, 16 voltmeters, main controller, and PC. The system was designed and implemented using the FPGA-based digital technology. The current source injects 50KHz sinusoidal current with the THD (total harmonic distortion) of 0.0029% and amplitude stability of 0.022%. The single current source and switching circuit reduce the measurement error associated with imperfect matching of multiple current sources at the expense of a reduced data acquisition time. The digital voltmeter measuring the induced boundary voltage consists of a differential amplifier, ADC, and FPGA (field programmable gate array). The digital phase-sensitive demodulation technique was implemented in the voltmeter to maximize the SNR (signal-to-noise ratio). Experimental results of 16-channel digital voltmeters showed the SNR of 90dB. We used the developed EIT system to reconstruct resistivity images of a saline phantom containing banana objects. Based on the results, we suggest future improvements for a 64-channel muff-frequency EIT system for three-dimensional dynamic imaging of bio-impedance distributions inside the human body.

• Proceedings of the Korea Technology Innovation Society Conference
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• 1998.05a
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• pp.16-16
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• 1998

기술혁신과 제도변혁의 와중에서 미국을 위시하여 우리나라, 일본, EU, 싱가포르등 세계 각국들은 경쟁적으로 2010년까지 초고속정보망을 구축할 것을 계획하고 있다. 더나아가서 미국 정부는 세계적인 초고속정보망 (Global Information Infrastructure: GII)을 구축하는 것을 계획하고 있다. GII 추진을 주도하고 있는 미국을 영상, 소프트웨어, 방송, 게임 등의 각종 멀티미디어 서비스의 절대적 경쟁력을 미국에서 뿐만 아니라 GII를 통해 세계시장으로 확대, 보호하겠다는 전략적 의미를 갖고 있다고 볼 수 있다. 미국의 GII 추진전략에 대응하여 일본은 AII 라는 아시아판 초고속통신망 구축과 개방화를 제안하였으며, 우리나라 정부는 APII라는 이름으로 아시아, 태평양지역 국가들을 대상으로 하는 초고속통신기반을 구축할 것을 제시하였다. 한국의 APII전략은 아시아, 태평양 지역 중심으로 한국의 국가적 위상을 제고하는 한편 우리나라 기업의 국제진출을 위한 전진기지로서의 활용측면에서 유효하다는 의미로서 제시하였다. 그러나, 우리나라가 제시한 APII의 청사진은 세계 정보통신시장을 중심으로 볼 때 경쟁력을 갖고 있는 정보통신부분이 반도체이외에는 전무하다는 측면에서 잘못하면 APII라는 전략은 미국이나 일본의 정보통신망 구축에 이용당할 가능성이 높은 무의미한 전략적 의미를 갖고 있는 것으로 보인다. 따라서 본 연구에서는 미국이 구축하고자 하는 GII체제와 병행하여 우리나라 정보통신산업을 육성, 발전시키기 위한 대응전략이 어떤 방향으로 전개되어야 할 것인지를 제시하기 위하여 GII가 갖고 있는 전략적 의미를 산업조직측면에서 살펴보고자 하였다. GII구축으로 인하여 세계의 정보통신 대기업은 초대기업으로 성장할 수 있는 기회이지만 중소기업 역시 대기업으로 성장할 수 있는 기회이다. 따라서 우리나라 정부는 정보통신산업정책을 초고속망 구축위주인 대기업 중심체제에서 중소기업이 참여 가능한 통신기기산업이나 멀티미디어 산업으로의 유인전환을 촉진할 필요가 있다. 다음으로 GII 구축에 따라 정보통신기업의 전략적 제휴 내지 합병이 활발히 촉진되고 있는 상황을 감안하여 볼 때 국내의 통신산업 역시 전략적 제휴 내지 합병이 가능할 수 있도록 정부규제를 완화할 필요가 있다. 그리고 정보통신서비스업체 역시 나름대로 독과점 산업인 통신기기업체내지 소프트웨어 산업으로의 진출이 가능할 수 있도록 상호진출을 허용할 필요가 있다고 본다. 이를 위해서 우리 나라 정부 역시 미국처럼 새로운 통신개혁법을 만들 필요가 있다. 새로운 통신개혁법의 핵심적인 사항으로서 첫째, 통신과 CATV간의 상호진입을 허용, 둘째, 통신사업자가 통신관련 기기산업에 참여할 수 있는 규제완화를 허용, 셋째, 유아단계에 있는 소프트웨어 및 컨테트산업을 육성하는데 산업육성책 수립 등을 적극적으로 추진하여야 할 것이다. 그리고 현재 국내 재벌기업들로 구성되어 있는 기반산업을 지원하는 기술개발 지원체제와 육성정책을 소프트웨어 및 컨텐트의 응용산업으로 개편할 필요성도 제시되며, 이를 위해 범부처 차원에서 소프트웨어 및 컨텐트 육성정책을 지원하는 종합적인 대책을 마련해야 한다고 본다.

• 대한공업교육학회지
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• v.36 no.2
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• pp.239-256
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• 2011

The purpose of this study is to deduce the effective improvement plans of engineering education system and to provide the base materials by analyzing satisfaction and problems in the perception survey of stakeholders related in engineering education system including Engineering Education Accreditation System. Engineering education system improvement plans from the results of study are as follows. First, government and university should provide more financial support to the college in order to improve education environment such as laboratories and equipment. Second, in order to improve links among engineering education stakeholders, student-professor, student-faculty, and colleges should operate effective mentoring program and consultation plan. Third, according to service quality evaluation, colleges need to give rewards to distinguished faculties for their outstanding work and build up job training about services in order to enhance satisfaction of students and professors, Also, business related to Engineering Education Accreditation System should be simplified and needs to increase the number of workers exclusively responsible for this work. Forth, in order to enhance comprehension of learning outcome and outcome of Engineering Education Accreditation System, it is necessary to improve Engineering education innovation center's status, to establish active systematic promotion system and to operate engineering education evaluation expert committee such as 'Engineering education system evaluation council'. Fifth, because of the stakeholder's shortage of benefits and tiredness accumulation, the issue of effectiveness in engineering education institutions has raised controversy. Thus, engineering education institutions needs to take measure necessary. Moreover, engineering education improvements should be improved by reflecting opinions from professors, faculties and students who are practically planning, operating and participating engineering education programs.

• Korean Journal of Cognitive Science
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• v.16 no.4
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• pp.369-386
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• 2005

Although Intelligent Tutoring System(ITS) offers individualized learning environment that overcome limited function of existent CAI, and consider many learners' variable, there is little development to be using at the sites of schools because of inefficiency of investment and absence of pedagogical content knowledge representation techniques. To solve these problem, we should study a method, which represents knowledge for ITS, and which reuses knowledge base. On the pedagogical content knowledge, the knowledge in education differs from knowledge in a general sense. In this paper, we shall primarily address the multi-complex structure of knowledge and explanation of learning vein using multi-complex structure. Multi-Complex, which is organized into nodes, clusters and uses by knowledge base. In addition, it grows a adaptive knowledge base by self-learning. Therefore, in this paper, we propose the 'Extended Neural Logic Network(X-Neuronet)', which is based on Neural Logic Network with logical inference and topological inflexibility in cognition structure, and includes pedagogical content knowledge and object-oriented conception, verify validity. X-Neuronet defines that a knowledge is directive combination with inertia and weights, and offers basic conceptions for expression, logic operator for operation and processing, node value and connection weight, propagation rule, learning algorithm.

• Cartoon and Animation Studies
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• s.31
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• pp.57-89
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• 2013

Animation tool has been made changes rapid development of animation from analog tool to digital authoring tool. Depending on the change in the status of digital authoring tools, education of digital authoring tool has brought many changes occurred in the institute and university. Digital authoring tool was insufficient for research of authoring tool due to the recognition that authoring tool is a simple tool. I try to resolve the difficulties through the analysis digital authoring tools to students studying at the university. In addition, Suggests social/cultural change of animation practitioners and effective training methods of digital authoring tools in the education of beginners and practitioners. This tool have perceptual knowledge and narrative knowledge. Since the language features and knowledge features is difficult to learn. it must be learned knowledge of computer graphics of professional level properly to learn. Then users should try to be creative within the authoring tool to produce creative results. also formed the community and to exchange information for self-development further it should form job market that authoring tool make formed through medium. So, I think that there is a need to change academically attitude to authoring tool. because this is not only the positive side but it occurs phenomenon to enslave users in authoring tool, and blind faith in the authoring tool or critical stance on software. It was a lot of pre-existing research that investigate engineering and industrial side in the authoring tool. Through this thesis, We will find social/cultural features and academic significance, and investigate that how to approach the method of education.

• Journal of Korea Water Resources Association
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• v.43 no.9
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• pp.769-780
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• 2010

Topological and hydraulic assessments to examine whether required demand and pressure are satisfied and using these assessed results as a criteria have been general methodology for reliability assessment of water distribution systems. However, many of existing studies that used nodal pressure calculated by hydraulic assessment for reliability assessment have two major issues to be solved. The one is that demand-driven analysis was used for hydraulic assessment and the other is that serviceability was not considered for reliability assessment. In addition, all of the studies used pressure-demand analysis which is suitable to hydraulic analysis for water distribution systems under abnormal operating condition considered only available nodal demand for reliability assessment. This means that advantages which can be obtained by pressure-driven analysis are not used properly and efficiently. In this study, new methodology for reliability assessment of water distribution systems using HSPDA model and distance measure method is suggested. This methodology considers both nodal pressure and nodal available demand for reliability assessment. Suggested methodology is applied to two water distribution systems to show its applicability and application results are compared with existing study.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.3
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• pp.221-229
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• 2013

In this paper, the image formation by the motion compensation technique for Synthetic Aperture Radar system(SAR) were realized through the computer simulation. The motion compensation technique performed image data with the range compression, the compensation procedure, the azimuth compensation and the noise elimination procedure. The range compression procedure transform the SAR raw data into the frequency domain and correlate with the range reference function and then inversely transform into the time domain. The compensation procedure contain the aircraft fluctuations compensation and the radar image degrading effect elimination procedure which was caused by image formation algorithm itself. The aircraft fluctuations compensation procedure perform the first stage which correct the phase angle and the second stage which calculate the Doppler frequency and determine the coordinate of the received signal. The radar image degrading effect elimination procedure also perform range migration compensation and the image defocussing effect compensation. The azimuth compression procedure transform the compensation data to the frequency domain and correlate with the azimuth reference function. The azimuth correlated data are inversely transformed to the time domain which is called SAR image data. When the above procedure were completed, the image data contains the received signals mixed with noise. The threshold technique was applied to elimination the noise from the mixed image data.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.7
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• pp.750-755
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• 2003

This paper proposes a new three-line balun. The equivalent circuit of the proposed three-line balun is presented, and impedance matrix［Z］of the equivalent circuit is derived from the relationship between the current and voltage at each port. The design equation for a given set of balun impedance at input and output ports is presented using［S］parameters, which is transferred fom impedance matrix,［Z］. To demonstrate the feasibility and validity of design equation, multi-layer ceramic(MLC) chip balun operated in the 2.4 GHz ISM band frequency is designed and fabricated by the use of the low temperature co-fired ceramic(LTCC) technology. By employing both the proposed new three-line balun equivalent circuit and multi-layer configuration provided by LTCC technology, the 2012 size MLC balun is realized. Measured results of the multi-layer LTCC three-line balun match well with the full-wave electromagnetic simulation results, and measured in band-phase and amplitude balances over a wide bandwidth are excellent. This proposed balun is very easily applicable to multi-layer structure using LTCC as shown in the paper, and also can be realized with microstrip lines on PCB. This distinctive performance is very favorable for wireless communication systems such as wireless LAN(Local Area Network) and Bluetooth applications.

• Composites Research
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• v.29 no.6
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• pp.342-346
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• 2016

Carbon fiber reinforced plastic (CFRP), one of lightweight materials, is the fiber structure using carbon fiber. It is the composite material that has the characteristics of carbon and plastic. As for the fiber structure, it has the great strength due to fiber direction. CFRP for woven type is used mostly as such a CFRP with lightweight. Woven type is more stable when compared with unidirectional type. On the other hand, woven type is highly priced. Therefore, this study aims to analyze the fiber structure of unidirectional CFRP. In this study, as the stacking angle [0/X/-X/0], X is the variable. This is unidirectional CFRP in which the angle phase of X has been reversed and stacked. By using such a unidirectional CFRP, the analysis model which had a crack at the center as the form of panel with the thickness of 2 mm was used. On analysis, the load is applied on the upper and lower parts being connected with a pin. The damage in the area near center crack was investigated. As for the analysis model, 3D surface model was designed by using CATIA. For CFRP stacking, the stacking direction was determined by using ACP in ANSYS program and the analysis model with two stacks was made. Afterwards, the structural analysis was carried out.

• Journal of the Korean Society of Radiology
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• v.9 no.5
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• pp.307-314
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• 2015

This study was conducted in reducing the involuntary motion artifacts because of lungs and heart movements as well as the aliasing artifacts generated during the use of the reduced-FOV EPI technique while performing breast MRI. Performed on a total of 38 obesity female subjects who visited the clinic for pre-examination before surgery within the period from August 1 to November 30, 2014. The 3.0T MRI scanner equipped with a breast scanning coil. Qualitative and quantitative analyses were each used for the evaluation of the acquired images while an Paired T-test and Wilcoxon rank test were performed to check the statistical significance. The variation ratio rose by 15.69% with the additional application of a pre-saturation pulse in the lesion, by 13.72% near the lesion, and 20.63% in the fat and the contrast-to-noise ratio rose by 10.58% in and near the lesion and by 12.03% in the lesion and fat, respectively. there were increases of 22.05% and 21.42% at 0 and 1000 respectively in qulitative evaluation and growth of 16.10% in apparent diffusion coefficient. it showed a statistically significant result(p<0.05) in signal to noise ratio, contrast to noise ratio, diffusion slope coefficient and apparent diffusion coefficient. The involuntary movements artifacts that occur in the phase encoding direction and the aliasing artifacts are considered to be reduced to obtain the best image in the additional use of the pre-saturation pulse as DWI is acquired.