• Journal of Electrical Engineering and Technology
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• 제8권6호
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• pp.1389-1399
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• 2013

A discrete controller is designed for low power dc-dc switched mode power supplies. The approach is based on time domain and the control loop continuously and concurrently tunes the compensator parameters to meet the converter specifications. A digital state feedback control combined with the load estimator provides a complete compensation, which further improves the dynamic performance of the closed loop system. Simulation of digitally controlled Buck converter is performed with MATLAB/Simulink. Experimental results are given to demonstrate the effectiveness of the controller using LabVIEW with a data acquisition card (model DAQ Pad - 6009).

• 전기학회논문지
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• 제64권8호
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• pp.1251-1255
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• 2015

The purpose of this study is to measurement the cardiac output using hand to hand impedance method to provide convenience to user when measuring SV(stroke volume) with the use of ICG(Impedance Cardiography). We suggest the optimized modified formula, which can be applied when using impedance with the use of hand to hand Impedance. To verify this formula, a SV from transthoracic approach and hand to hand approach are compared for the 36 subjects, respectively. The acquired data was analyzed by using LabVIEW 8.6, analysis was implemented by SPSS 12.0. Fine difference was shown by individual. We showed that as a result of analyzing the ICG measurement value on thoracic and hand to hand, the correlation with SV was r=0.716, thereby having indicated the results of regression model in relatively high correlation.

• 센서학회지
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• 제19권3호
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• pp.184-190
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• 2010

In this paper, a remote submersion warning system based on multi-mode optical fiber(MMF) sensors and a wireless sensor network(WSN) are proposed. To improve the reliability and stability of the sensors, the dual optical fiber sensors combined to the optical coupler are demonstrated. A slave zigbee as a wireless sensor module was used as a platform to monitor and record the signal from the MMF sensors and then transmits these information to a master zigbee wirelessly. The monitoring system running the $LabVIEW^{(R)}$ software was connected to the internet to support the short message service(SMS) through extensible markup language(XML) web service. No matter where the managers are, they can always receive the real-time remote-monitoring data for safety check.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제19권3호
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• pp.289-303
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• 2015

In this paper, an optimal guidance law with terminal angle constraint considering the seeker's lock-on condition, in which the target is located within the field-of-view (FOV) and detection range limits at the end of the midcourse phase, is proposed. The optimal solution is obtained by solving an optimal control problem minimizing the energy cost function weighted by a power of range-to-go subject to the terminal constraints, which can shape the guidance commands and the missile trajectories adjusting guidance gains of the weighting function. The proposed guidance law can be applied to both of the midcourse and terminal phases by setting the desired relative range and look angle to the final interception conditions. The performance of the proposed guidance law is analyzed through nonlinear simulations for various engagement conditions.

• 한국정밀공학회지
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• 제26권7호
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• pp.120-126
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• 2009

Thermal displacement of high speed spindle is very important problem to be solved. To solve heat generation and thermal displacement problems that influence on the product accuracy, it is very important to predict thermal characteristics of the spindle and it is positively necessary to select the conditions of cooling, flow rate and preload of bearings. In this paper, 30,000rpm($1.455{\times}10^6DmN$) spindle was designed and produced. The analysis of thermal deformation for heat generation of inner spindle was carried out using commercial program $ANSYS^{(R)}$ and the result was compared with measured data using $LabVIEW^{(R)}$ and SGXI-1600, 1125 and 1126 module. Temperature distribution and thermal displacement according to spindle speed are measured. Using this method, it is possible to predict and to improve thermal characteristic of high speed spindle by control spindle speed, bearing preload and cooling rate.

• 치과방사선
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• 제28권1호
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• pp.111-126
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• 1998

In this study, radiographic evaluation was made using panoramic radiography and cross-sectional tomography of SCANORA/sup (R)/ in male and female adults in their 20's on the relationship between the maxillary sinus floor and the apex of the maxillary molar, to test the accuracy and effectiveness of the cross-sectional tomography, and to use this information in the assessment of preop. and postop. root canal treatment, apical surgery, extraction and implantology. Forty-one adults with an average age of 24.4 years were studied using panoramic radiography and cross-sectional tomography. In panoramic view and cross-sectional view, the position of the apices of maxillary molars were classified as separated, contacted, or protruded type; the general shape of the maxillary sinus floor was evaluated horizontally and vertically from cross-sectional tomography. The accuracy of each radiography was tested using maxilla from 5 fresh cadavers from the Anatomy Lab at Yonsei University Dental College, and panoramic view and cross-sectional tomography were taken in the same condition as with the patients. The results were as follows: 1. Panoramic view and cross-sectional view were taken in the maxilla specimen, and the actual distance between the maxillary sinus floor and the tooth apices were measured in the specimen; the median values of the distance from the tooth apices to the maxillary sinus floor in the panoramic view, cross-sectional view and in the actual maxilla specimen were 2.83 mm, 4.51mm, and 4.l5mm, respectively. In the cross-sectional view, the measured distance was close to the actual distance but in the panoramic view, the measured distance was far from the actual distance. 2. When the results of the panoramic view and cross-sectional view were compared, 40.5％ of the results agreed with each other in the two radiographic methods and buccal roots of the 2nd molar were the closest to the maxillary sinus floor in the cross-sectional tomography. 3. In cross-sectional view, when the vertical relationship of the maxillary sinus floor and maxillary roots was assessed, in 1st molars, type II (the sinus floor that extends down to the buccolingual furcation area) was predominant, while in 2nd molars, type I (the sinus floor located above the level connecting the buccal and lingual apices) was predominant. In the horizontal relationship, in 1st molars, type II (the lowest floor of the maxillary sinus located in between the buccal and lingual roots) was predominant; in 2nd molars, type I (the lowest floor of the maxillary sinus located on the buccal side of the buccal roots) and type II appeared in similar frequency. In conclusion, the SCANORA/sup (R)/ cross-sectional tomography was more effective than the frequently used panoramic view, in that the relationship of the maxillary molars and maxillary sinus floor can be evaluated more accurately and the buccolingual cross-sectional view can also be observed. And maxillary sinus floor that was close to maxillary 2nd molar had tendency to be located on buccal side than that close to 1st molar. Therefore, cross-sectional tomography is an effective and accurate method to evaluate the position of the teeth in relation to the sinus floor preoperative and can be easily used to diagnose localized periapical lesions. Also, the image quality obtained was quite satisfactory.

• 과학기술학연구
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• 제19권3호
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• pp.247-289
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• 2019

이 연구는 사회문제 해결형 연구개발사업에 참여했던 세 사회적경제조직의 경험을 통해 한국의 국가연구개발사업에서 성공적인 시민참여가 이루어지기 위한 조건을 논의한다. 사회문제 해결형 연구개발사업은 리빙랩과 더불어 사회적경제조직의 참여를 필수요건으로 제시함으로써 새로운 형태의 시민참여를 국가연구개발사업에 도입하였다. 사회문제 해결형 연구개발사업의 요구조건은 연구책임자가 사회적경제조직을 사업단에 초대하게 했으나, 이러한 초대는 서로에 대한 충분한 이해가 동반되지 못한 채, 갑작스럽고 우연히 이뤄졌다. 이러한 형식의 제도적 장치는 한편으로사회적경제조직의 혁신활동 경험과 과제 사회적경제조직의 연구개발사업에의 참여를 유도했지만 다른 한편으로 이들이 과학기술전문가들이 주도하는 연구개발사업에 종속적으로 참여하도록 만드는 역할을 하였다. 한편 이들에게 사회문제 해결형 연구개발사업이 요구하는 과업인 리빙랩은 늘 해오던 활동의 연장선에 있는 익숙한 것으로 인식된 반면, 연구비처리 등 복잡한 행정절차가 가장 낯설고 어려운 경험이었다. 연구개발사업에서 주체별 지향의 차이도 분명했다. 사회적경제조직은 리빙랩에 참여하는 시민들이나 자신들은 개발된 제품의 실용화에 초점을 맞추는 반면, 과학기술자들은 상대적으로 연구에 초점을 맞춘다고 인식했다. 이러한 지향의 차이는 연구개발과정에서 마찰을 빚기도 했고, 과학기술자와는 달리 사회적경제조직이 자신이 참여했던 사회문제 해결형 연구개발사업을 성공적이지 못한 사업으로 평가하는 핵심적인 이유이다. 그럼에도 불구하고 이들의 국가연구개발사업 경험은 개인에게나 조직에게나 혁신의 주체로 성장하는 데 중요한 학습기회를 제공했다.

• 한국실천공학교육학회논문지
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• 제1권1호
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• pp.99-105
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• 2009

Web을 이용한 컴퓨터기반의 학습은 교육을 위한 유용한 적용방법이다. 이런 방법은 애니메이션과 상호작용을 통해 제공되어 지고 복잡한 설비들은 교본을 통해 쉽게 학습할 수 없다. 웹/인터넷이 가능한 응용문제들은 원격지에서 제어되고 모니터링 될 수 있으므로 전 세계 원격지 대학, 연구소 또는 회사에서 다양한 방법으로 충분히 사용된다. 컴퓨터와 전자기술의 결합을 통한 저가의 하드웨어 개발은 이전에 비해 웹/인터넷 기반기술의 발전을 통해 특별히 교육기관을 위해 만들어졌다. 따라서 이런 분야에 적합한 기술개발은 광범위한 웹기반 교육의 확장과 이를 위한 기술개발 적절한 투자가 필수적이다. 원격 가상계측기의 응용은 실험을 통해 검증되어져야 하며 공학도를 위해 실험이 가능할 수 있도록 적용되어야 한다.

• Toxicological Research
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• 제21권1호
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• pp.1-14
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• 2005

Transgenic mouse models have been introduced and accepted by regulatory bodies as an alternative to carcinogenicity assay models to predict and evaluate chemical carcinogens. The recent research outcomes in transgenic mouse models have made progressive advances in the understanding of chemical carcinogenesis and the evaluation of potential human carcinogens. However, these models still remain to be insufficient assay systems although the insufficiencies have been recognised and are being resolved. Based on up to date information from literature, this review article intends to understand currently accepted transgenic mouse models, issues arising from study design, interpretation of the study, results of validation project and their cancer prediction rate, and further perspectives of cancer assay models from the regulatory view point.

• 한국도로학회논문집
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• 제19권2호
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• pp.127-135
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• 2017

PURPOSES: The objective of this study is to evaluate the effect of anti-stripping on asphalt mixtures constituting anti-stripping agents. METHODS : Based on the literature review, asphalt mixture added with anti-stripping agents was prepared, and these asphalt mixtures were evaluated for anti-stripping properties for each anti-stripping agent through various lab tests, namely, tensile strength ratio (TSR), dynamic immersion test, uniaxial compression test, and indirect tensile strength test (IDT). The liquid anti-stripping agents used in the lab test were premixed with each asphalt binder (PG 64-22, PG 76-22) before being mixed with the aggregate. RESULTS :The result of the TSR test revealed that the effect of anti-stripping was highest when hydrated lime and liquid anti-stripping agent W were added. The correlation coefficient $R^2$ between the TSR result and cohesion ratio is 0.99, which indicates that the sensitivity of the TSR to moisture damage is reliable from the mechanical point of view. The covering ratio of the asphalt binder to the liquid anti-stripping agent W was determined to be higher than that to the other liquid anti-stripping agents. CONCLUSIONS :It is considered that the improved moisture resistance of asphalt mixture as a result of the use of anti-stripping agents can reduce the incidence of various pavement damages such as portholes caused by stripping, and the performance life of the asphalt road pavement can be prolonged.