• Transactions of the Korean Society of Mechanical Engineers B
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• v.22 no.3
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• pp.386-398
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• 1998

The present experiment is conducted to investigate heat transfer characteristics on the impinging surface with secondary flows around circular nozzle jets. The changed vortex pattern around jet affects significantly the flow characteristics and heat transfer coefficients on the impinging surface. The effects of the jet vortex control are also considered with jet nozzle-to-plate distances and main jet velocities. The vortex pattern around a jet is changed from a convective instability to an absolute instability with a velocity suction ratio of the main jet and the secondary counterflow. With the absolute instability condition, the jet potential core length increases and the heat transfer on the impinging surface is increased by small scale eddies. The region of high heat transfer coefficients is enlarged with the high Reynolds number due to increasing secondary peak values. The effect of suction flows is influenced largely with collars attached the exit of the jet nozzle because the attached collar guides well the counterflow around the main jet.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.1367-1370
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• 2009

We have developed a 2D-3D convertible 7" autostereoscopic mini-monitor with high 3D quality, in which the parallax barrier LCD is attached on the TFTLCD. The excellent optical performance was achieved by design of the ghost free barrier and precise assembly between the barrier layer and the TFT-LCD panel. Our design principle and fabrication technology suppressed 3D cross-talk and improved viewing angle. In this paper, the design and fabrication process of the 3D mini-monitor are described. The evaluation for the 3D performance is also discussed.

• Journal of the Microelectronics and Packaging Society
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• v.20 no.3
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• pp.23-29
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• 2013

Development of flexible electronic devices has primarily focused on printing technology using organic materials. However, organic-based flexible electronics have several disadvantages, including low electrical performance and long-term reliability. Therefore, we fabricated nano- and micro-thick silicon film attached to the polymer substrate using transfer printing technology to investigate the feasibility of silicon-based flexible electronic devices with high performance and high flexibility. Flexibility of the fabricated samples was investigated using bending and stretching tests. The failure bending radius of the 200 nm-thick silicon film attached on a PI substrate was 4.5 mm, and the failure stretching strain was 1.8%. The failure bending radius of the micro-thick silicon film attached on a FPCB was 2 mm, and the failure strain was 3.5%, which showed superior flexibility compared with conventional silicon material. Improved flexibility was attributed to a buffering effect of the adhesive between the silicon film and the substrate. The superior flexibility of the thin silicon film demonstrates the possibility for flexible electronic devices with high performance.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.17 no.6
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• pp.29-39
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• 2007

RSA is one of the most popular public-key crypto-system in various applications. This paper addresses a high-speed RSA crypto-processor with modified radix-4 modular multiplication algorithm and Chinese Remainder Theorem(CRT) using Carry Save Adder(CSA). Our design takes 0.84M clock cycles for a 1024-bit modular exponentiation and 0.25M cycles for a 512-bit exponentiations. With 0.18um standard cell library, the processor achieves 365Kbps for a 1024-bit exponentiation and 1,233Kbps for two 512-bit exponentiations at a 300MHz clock rate.

• Journal of Nutrition and Health
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• v.4 no.4
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• pp.9-13
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• 1971

To evaluate the results of nutrition education in high school, the contents of the lunch box of senior high school girls were surveyed. Among 540 students in Attached Senior High School, College of Education, Seoul National University, 403 girls who had carried a lunch box were selected as a subject. All the nutrients except vitamin D given in Recommended Daily Dietary Allowances were calculated for the foods in lunch box and compared with the Recommended Allowances for Korean people, and foods in lunch box were also considered as a food groups. To see how many students had an interest about their own nutrition, people who packed lunch box were also checked. Results are as follows 1) all the nutrients except iron and niacin of lunch box were low when compared with Recommended Daily Dietary Allowances for Korean people 2) Over 50% of calorie, protein, vitamin $B_1$, and niacin were provided by main food-rice, although other nutrients were principally from side dish. 3) Side dishes were few in kinds and chiefly salty foods such as preserved and processed foods were in the lunch box. There was no consideration in cooking method. 4) There may be a fault in nutrition education in high school because, there were only few students who had an interest in their own nutrition.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1598-1602
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• 2003

The parallel-type mechanism provides more accurate and stiff motion than the serial-type mechanism. However, in case of using the haptic device, the performance of the force reflection can be deteriorated due to the singular points existing in workspace. In this paper, we propose a redundantly actuated parallel 3-DOF haptic device, which is singularity-free in the workspace and has an improved force reflection capability. In addition, we propose a new force distribution algorithm, which can reflect force of both high and low resolution, using two sets of actuator with different size. Redundant actuators are attached to the base frame in order to minimize the inertia of the system. Moreover, a wire and gear reduction system is employed to achieve high force reflection along with soft feeling. We confirm the performance of the force reflection capability throughout simulation.

• Journal of Institute of Control, Robotics and Systems
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• v.22 no.8
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• pp.579-584
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• 2016

When surgical instruments are tracked in an image-guided surgical navigation system, a stereo vision system with high accuracy is generally used, which is called optical tracker. However, this optical tracker has the disadvantage that a line-of-sight between the tracker and surgical instrument must be maintained. Therefore, to complement the disadvantage of optical tracking systems, an internal vision sensor is attached to a surgical instrument in this paper. Monitoring the target marker pattern attached on patient with this vision sensor, this surgical instrument is possible to be tracked even when the line-of-sight of the optical tracker is occluded. To verify the system's effectiveness, a series of basic experiments is carried out. Lastly, an integration experiment is conducted. The experimental results show that rotational error is bounded to max $1.32^{\circ}$ and mean $0.35^{\circ}$, and translation error is in max 1.72mm and mean 0.58mm. Finally, it is confirmed that the proposed tool tracking method using an internal vision sensor is useful and effective to overcome the occlusion problem of the optical tracker.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2000.11c
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• pp.569-577
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• 2000

The position of tobacco leaves is affluence to the quality. To evaluate its quality, sample leaves was collected according to the position of attachment. In Korea, the position was divided into four classes such as high, middle, low and inside positioned leaves. Until now, the grade of standard sample was determined by human expert from korea ginseng and tobacco company. Many research were done by the chemical and spectrum analysis using NIR and computer vision. The grade of tobacco leaves mainly classified into 5 grades according to the attached position and its chemical composition. In high and low positioned leaves shows a low level grade under grade 3. Generally, inside and medium positioned leaf has a high level grade. This is the basic research to develop a real time tobacco leaves grading system combined with portable NIR spectrum analysis system. However, this research just deals with position recognition and grading using the color machine vision. The RGB color information was converted to HSI image format and the sample was all investigated using the bundle of tobacco leaves. Quality grade and position recognition was performed through well known general error back propagation neural network. Finally, the relationship about attached leaf position and its grade was analyzed.

• Journal of The Korean Association For Science Education
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• v.10 no.2
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• pp.55-66
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• 1990

This study aimed at identifying the characteristics of current Earth Science Curricula in several countries in terms of their format, objectives and contents and discussing about them. The curricula(including textbooks) were collected from 6 countries The United States of America, England, Australia, Japan and The Republic of China. Here are the results of this study ; 1. Earth Science should be teached in high school and assigned at least 8-10 unit. 2. In Earth Science objectives, scientific inquiry methods through observation and experiment and mutual relationship among science, technology and society must be stressed. 3. The contents of Earth Science must did with experimental and activity rather than understanding in order to induce students to how more intersts in Earth Science. 4. There is a growing tendency for Earth Science Education to be attached importance to life environment and career education.

• Journal of the Korean Society of Clothing and Textiles
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• v.23 no.2
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• pp.230-241
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• 1999

The purpose of this study was to investigate the purchasing behavior of adolescent consumer groups divided by their brand orientation. Questionnaires were administered to 507 middle and high school students who resided in Kwang-ju between September 22-27 1997. Data were analyzed by factor analysis cluster analysis ANOVA Duncan-test frequency and {{{{ chi ^2 }}-test. The results were as follows : 1. Adolescent consumers were classified by three groups ; brand attached groups : brand attached group (Group I) brand interest group (Group II) and brand indifference group (Group III) according to their brand orientation. 2. There were significant differences among groups in using information sources : Group II used more sources of information than the other two groups. 3. As evaluating attributes of product Group I considered brand prestige most important Group II considered design fashionablity imfortant orderly and Group III considered pricemost important. 4. Group I patronised expensive brand chain stores Group II patronseied department stores and Group III prefered independently owned cheaper priced retailers. 5. The apparel purchasing price range was higher for Group I and became lower for Group II Group III.