• Transactions of the KSME C: Technology and Education
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• v.1 no.1
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• pp.1-6
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• 2013

A SIM card socket is used for a cell phone to fix an USIM card and a push-push mechanism is typically employed in the SIM card socket for a user convenience. A SIM card is inserted with locking when a user pushes the card once and a SIM card is removed with unlocking when a user pushes the card again. A push-push mechanism is operated by a heart-cam structure and a main spring. A cam slider and a cam stick consisting a push-push mechanism may be broken because of the main spring. So, dynamic stress at a cam slider and a cam stick which is generated by a main spring during operating should be analyzed and considered in the push-push mechanism design. In this paper, a flexible multibody model of a push-push mechanism was developed to analyze dynamic stress at a cam slider and a cam stick.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.20 no.2
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• pp.112-121
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• 1984

This paper is compared the simulation tables by the general propagation velocity and the calculated propagation velocities with distances and times to take to be transmitted Loran C wave from master station to slave stations, with Loran C tables, and compared the accuracy of position fixes by the simulation to them by Loran C table with the time differences of 9970 chain to be measured in the south coast of Korea, and by the simulation with the time differences of 5970 chain to be measured at definite position to them. The results obtained are as follows; 1. the simulation tables by the calculated propagation velocities is nearer to Loran C tables than it by the general propagation velocity. 2. The ranges of total errors of the simulation positions by the general propagation velocity and the calculated propagation velocities to the position fixies of Loran C table with the time differences of 9970 chain to be measured in the south coast of Korea are 0.2-0.7 miles, 0.01-0.1 miles, and the mean values of them are 0.46 miles and standard deviations of time are 0.1 miles, 0.03 miles respectively. 3. Mean value of total errors of the simulation position by the calculated propagation velocities to the definite position with the time difference of 5970 chain is 0.2miles and is reduced 0.1-0.2 miles than it by the general propagation velocity.

• Journal of Korean Home Economics Education Association
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• v.1 no.1
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• pp.53-62
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• 1989

Cooking practice is keenly related to not only the betterment of family health but to the improvement of dietary life. Cooking is a kind of practical skill and one is skill in it by repeated practice. The aim of cooking practice in school is to fix cooking method practically and scientifically, to acquire cooking skill. To achieve this aim there are many unrecognized or unsolved problems in the first-line schools. The problems and efficient ways of cooking practice in the middle and high school are as follows； 1. The aim of cooking practice： It should be first of all remembered that the practice is so practical that the knowledge and skill of cooking should be related to the future domestic life. Second, the practice should be able to serve the communal and national life by scientifying and improving life. 2. The content of the practice： First, it should be so arranged step by step that the content of each year should not be repeated. Second, the ratio of Korean cooking practice should be increased and the material of the practice should be chosen in consideration of the peculiarity of the community, seasons and economical problems so that it may be applied to the very day life. Third, to improve dietary life, the practice should be a way of the simplification of dietary life, of the nutritional efficiency. Forth, for the betterment of physical condition of the family the practice should involve balanced dietary plans and dietary therapy. 3. Teaching method： First, the practice should be scientific and comprehensive in consideration of not only cooking skills but also knowledge of nutrition. Second, micro-class system should be adopted, and practice labor should be allotted each student to develop cooperative attitude and the sense of responsibility. Third, in addition to the practice conducted in a body, comparative cooking, applicable cooking and experimental ability and the content of the text. Fourth, teachers should let the students examine and find problems by bringing them to a focus on the basis of theory. 4. Administration method： First, the practice schedule should be planned that a class has practices at least more than twice a semester. Second, two hours of class should be continued without cessation after beforehand survey and theory study. Third, facilities and utensils for practice should be enlarged. That is, cooking practice rooms, tools, utensils should be prepared. Fourth, enough cost of practice should be secured. The above mentioned points show the present situation and problems with which cooking practice teaching is confronted. In order to normalize cooking practice teaching, the first-line schools should give the above mentioned problems their careful consideration and improve the present situation so that efficient, creative, practical cooking practice will be possible.

• Journal of Appropriate Technology
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• v.7 no.1
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• pp.51-58
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• 2021

This study proposes the design and implementation of a low-cost emergency ventilator which can be helpful during the COVID-19 pandemic where the supply of automatic ventilators is not smooth compared with the urgent demand worldwide. Easy implementation and lower price were made possible by using AMBU-bag and off-the-shelf embedded micro-controller board. Moreover, while 3D printing is used by companies and experts around the world to build prototype hardware, materials which are readily available from surrounding environments so that people in countries where it is difficult to access many advanced technologies could manufacture the system. The design features AMBU-bag automation, not use 3D printing, and it can contrl speed. By allowing speed control, ventilation can be performed according to the conditions of the patient being used. A complementary point in the study is that it is difficult to fix the start point of the wiper motor used first. A method for complementing this is a method for replacing the brush DC motor with a position feedback function. Secondly, the AMBU-bag may wear out in the long-term process of compressing the AMBU-bag because the arm and the fixing frame are made of wood. To complement this, the part of fixing frame and arm parts that the AMBU-bag touches need to be wrapped in a material such as silicon to minimize friction.