• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.2 s.173
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• pp.481-488
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• 2000

This paper presents a new passive gravity -compensating system for articulated robot manipulators. The system, which consists of linear zero- free -length springs, achieves exact counterbalancing o f the gravitational loads throughout the entire range of the manipulator workspace, A basic concept is to design springs such that the total potential energy of the system including the manipulator and the springs should be maintained constant. A prototype has been developed for a direct-drive five-bar manipulator and its performances have been investigated. Results show that the gravity-induced motor torques have been reduced to less than 5% of those of uncompensated robots. Also, the gravity-compensating system simplifies the position control algorithm while maintaining the trajectory-tracking errors in a satisfactory level. In conclusion, the proposed system efficiently improves the manipulator performances by reducing the driving motor size and the energy consumption as well as by simplifying the control systems.

• Journal of the Korea Furniture Society
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• v.24 no.2
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• pp.148-155
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• 2013

Appear on the furniture design concept of the Joseon Dynasty Pung-hyel design was developed that is imaged by implication. Was enough of our culture, tradition and the wisdom of our ancestors to the development of a design that reflects the traits to fit the purpose of each form to proceed. Based building materials, technology, and how to identify and develop products as competitive PE fence, and at the same time to develop an international product design is based. Was designed with functionality and mass production to be faithful as a function fence productivity. Formative elements where you can rub shoulders with the modern urban environment alive excavated features leads in the traditional culture, aesthetics, design emphasized a new sense of harmony. Improvements were becoming increasingly aware that traditional culture of Korea's own traditional forms of social concern of modern design. Other products and take advantage of the traditional pattern, with figurative motifs and differentiation, and faithful to its original function as a fence brings out the basic elements of the visual motif has a distinctive beauty.

• Journal of Korea Society of Digital Industry and Information Management
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• v.5 no.2
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• pp.29-37
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• 2009

Recently, the structure of simulation environment is important issue in all fields. In case of the training for operating the machines which are costly such as airplanes or spaceships, simulators could be helpful for decreasing the costs and training effects by simulating real situation. When we get the driving license, too many peoples are waiting for their turns because of limited cars and testing spaces in Korea. To solve this problem, we've designed and developed the basic design for the simulators. We suggested the Computer 3D Simulation Model for practice of a drives's license. The concept of this simulator was from a 3D Racing-game which suit for driving exercise. We provide users with handle-controlled simulation setting in order that users feel reality as if they drive really through this simulator. We also use 'force-feedback' system which give handle vibration in case users collide against obstacles or exceed the line since users can absorb the simulation program and feel the sense for the real. This paper is the study about modeling the driving exercise model made use of 'computer 3D simulation', and producing and utilizing the simulator through this modeling.

• The Mathematical Education
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• v.41 no.3
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• pp.341-360
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• 2002

The purpose of the study was to investigate the effectiveness of dynamic software in solving high school analytic geometry problems compared with traditional algebraic approach. Three high school students who have revealed high performance in mathematics were involved in this study. It was considered that they mastered the basic concepts of equations of plane figure and curves of secondary degree. The research questions for the study were the followings: 1) In what degree students understand relationship between geometric approach and algebraic approach in solving geometry problems? 2) What are the difficulties students encounter in the process of using the dynamic software? 3) In what degree the constructions of geometric figures help students to understand the mathematical concepts? 4) What are the effects of dynamic software in constructing analytic geometry concepts? 5) In what degree students have developed the images of algebraic concepts? According to the results of the study, it was revealed that mathematical connections between geometric approach and algebraic approach was complementary. And the students revealed more rely on the algebraic expression over geometric figures in the process of solving geometry problems. The conceptual images of algebraic expression were not developed fully, and they blamed it upon the current college entrance examination system.

• The Mathematical Education
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• v.51 no.2
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• pp.161-171
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• 2012

Generally mathematics is regarded as a subtle subject to grasp their true meaning. And teacher's personal conceptions of mathematics influence greatly on the teaching and learning of mathematics. More over often teachers confess their difficulties in explaining the true nature of mathematics. In this paper, applying the theory of epistemology, we tried to search factors that must be counted important when trying to understand the true nature of mathematics. As results, we identified five characteristics of mathematical knowledge such as logical reasoning, abstractive concept, mathematical representation, systematical structure, and axiomatic validation. Next, we tried to investigate math education major students' conception of mathematics using these items. To proceed this research we asked 51 students from three Universities to answer their opinion on 'What do you think is mathematics?'. Analysing their answers in the light of the above five items, we got the following facts. 1. Only 38% of the students regarded mathematics as one of the five items, which can be considered to reveal students' low concern about the basic nature of mathematics. 2. The status of students' responses to the question were greatly different among the three Universities. This shows that mathematics professors need to lead students to have concern about the true nature of mathematics.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.28 no.3
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• pp.18-26
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• 2020

Cost reduction and equality by exempting re-scanning of passengers, baggage and cargo secured from the first airport of departure, mainly in the European Union/European Economic Area(EU/EEA), Switzerland, etc. One-Stop Security(OSS) is being promoted to maintain the level of security while increasing speed and convenience, and movement is expected to expand worldwide. Therefore, this paper establishes the basic concept of OSS through a literature review of ICAO Standards and Recommended Practices(SARPs), and analyzes the actual conditions of OSS implementation in major countries such as the United States and the EU. It is intended to present the political, economic benefits for Korea and highlight the urgency of implementing the OSS system in the aviation industry including the cargo sector. Therefore, the practical implications of strengthening international cooperation through the expansion of government and airport operators OSS implementation to overcome the resource shortage problem of the existing national air cargo security system and to strengthen the status as a global aviation powerhouse were drawn up. There is academic significance that it raised the need for effective implementation of OSS, which was not previously covered.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.12 s.243
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• pp.1645-1652
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• 2005

Pick-and-place systems using suction cups have been being widely used and continuously developed in production automation. There are, however, some drawbacks in constructing such systems. One of them is that it generates high level noise due to air compressors. And the system must have complex constitutions of mechanical component such as air compressors, air tubes, air valves, etc. Moreover, it needs continuous air supply to maintain vacuum in suction cups. If there is a failure in any suction cup, the total suction system may fail owing to air leakage. To overcome these drawbacks, we propose PMS (Permanent Magnet Suction) mechanism which has permanent magnets for vacuuming suction cups with no air compressor. The basic concept of PMS mechanism is to rotate permanent magnets with fixed angle. Simple rotation of permanent magnets changes the direction of the magnetic force applied at the suction cups. Since each suction cup has no direct connection with any of the others, the air leakage at one suction cup is not critical. The proposed suction mechanism was designed and fabricated. With some experiments, the feasibility and performance of the PMS mechanism was shown. The strong points of the PMS mechanism are in its simple structure, generating low noise, high energy efficiency, and no need of continuous energy supply.

• ALGAE
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• v.20 no.2
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• pp.91-97
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• 2005

The brown algal family Chordariaceae sensu lato is a focus of taxonomy because recent studies suggest a broad concept of the family, including genera formerly classified in the Dictyosiphonales. Using morphology, plastid rbcL and nrDNA ITS sequences, we evaluated relationships of the monotyic genus Soranthera (S. ulvoidea), which has been classified in the Punctariaceae. The species occurs in Bering Sea and Aleutian Islands, Alaska to Baja California. Thalli are globose to lobed, hollow, 3-5 cm in diameter, and covered with evenly distributed sori. However, two forms within the species are recognized: f. ulvoidea for globose forms and f. difformis for lobed forms. Plastid rbcL and nuclear ITS region sequences were newly determined in samples of S. ulvoidea from the Pacific coast of the North America. We found little variations in the ITS sequences among samples of S. ulvoidea from five different locations and in the rbcL region from two different locations. These results do not support previous classification of f. ulvoidea and f. difformis within the species. All analyses of our rbcL sequence dataset show that Soranthera was placed in the Chordariaceae s.l., but more related to Botrytella than Punctaria and Asperococcus.

• Research in Community and Public Health Nursing
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• v.13 no.4
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• pp.808-816
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• 2002

Purpose: The study was aimed to assess the competency and professional attitude of school health nurses who are occupied with adolescent health, and to provide basic information for the development of continuing education programs for them to improve their competencies. Method: The self-reported questionnaire based on WHO assessment tool were used to assess the competencies of the school health nurses providing health care for adolescents. The subjects were 584 school health nurses and the data were collected from January 28 to March 5, 2002. Result: The school health nurses in middle schools showed significantly higher scores than the school health nurses in primary schools on the level of competency. The nurses were scored the highest in the area of dealing with sexual issues for the students, followed by providing them direct care and application of primary care concept to the field of school health nursing. The areas showing the lowest scores were counseling and utilization of the system. There was a significant positive correlation between competency and professional attitude of the school health nurses. Conclusion: Based on the results of this study, it is necessary to develop various continuing educational programs for school health nurses using different teaching methods such as web-based program.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.12
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• pp.4742-4751
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• 2010

The purpose of this study was to identify the perceptions of local food to activate the school meal service. This study examined the concept of local food in Korea and its usage the definition and benefit of local food has been done through experts who are food producers or distributors, and operators related in school meal. The result of this study could be provided a basic items of survey for further research to identify the consumers' perceptions on using local food.