• Journal of Korean Elementary Science Education
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• v.41 no.3
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• pp.538-552
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• 2022

This study attempted to understand the characteristics of pedagogic activities performed by pre-service elementary school teachers. To this end, it applied Algodoo simulations to analyze the actions of students and obtain educational implications for optical learning. The study's participants comprised 79 first-year students enrolled in a teacher training college. Their activities could be classified as representation reproductions, verification experiments, and inquiry experiments. Students who performed representation reproduction exercises replicated renowned and authoritative exemplars, apprehending and demonstrating their principal features through simulations. Students performing verification experiments attempted to validate previously learned optical concepts by reviewing the relevant theoretical contexts. Such students primarily conducted simple experiments. Students accomplishing inquiry experiments used simulations to explore phenomena they did not know. Some of them even investigated optical phenomena beyond the domain of general physics. The above results confirmed that free optical experiments performed using Algodoo can effectively denote starting points for learners to engage in activities at varying levels. Additionally, students require assistance from instructors in addressing queries about the application of the principles and models related to optics. This study suggests ways in which instructors should help students at each level of activity. Additionally, the paper presents examples of varying levels of inquiry-related activities available on Algodoo. It also discusses the advantages and disadvantages of performing inquiry-based activities on Algodoo and suggests ways of enhancing the learning achieved through this platform.

• Journal of Internet Computing and Services
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• v.6 no.6
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• pp.71-83
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• 2005

In this paper, we developed the Distributed Programming Developing Tool(DPDT) which can make distributed application program efficiency based on the distributed object group framework supporting group management and dynamic binding for object resources requested from clients on distributed systems. The distributed object group framework we constructed provides not only the group register/withdraw, the access right and the name/property services for server objects from a point of view of group management services, but also dynamic binding, replicated object supporting, load balance, and federation among the object groups from a point of view of the supporting services of distributed application, When developing distributed application, by using our tool, server programming developer implements objects in each server system, next registers the properties to need for service provision to the object group. Client programming developer can also develop client program easily by obtaining the access right for the object or the object group and using the properties of objects with the access right permitted to the client. For providing above application developing environment in this paper. we described the definition of object group, the architecture of the distributed object group framework which our tool supports, and its functionalities, then specified the 3 GUI environments of DPDT implemented for providing efficient interfaces between the distributed object group and distributed applications. Finally, by using the DPDT, we showed the group register/withdraw and the access right grant procedure of objects which are server programs, the developing process of client program, and the executing results of the distributed application developed.

• Applied Microscopy
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• v.2 no.1
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• pp.39-46
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• 1972

There are many kinds of microscopes suitable for general studies; optical microscopes(OM), conventional transmission electron microscopes (TEM), and scanning electron microscopes(SEM). The optical microscopes and the conventional transmission electron microscopes are very familiar. The images of these microscopes are directly formed on an image plane with one or more image forming lenses. On the other hand, the image of the scanning electron microscope is formed on a fluorescent screen of a cathode ray tube using a scanning system similar to television technique. In this paper, the features and some applications of the scanning electron microscope will be discussed briefly. The recently available scanning electron microscope, combining a resolution of about $200{\AA}$ with great depth of field, is favorable when compared to the replica technique. It avoids the problem of specimen damage and the introduction of artifacts. In addition, it permits the examination of many samples that can not be replicated, and provides a broader range of information. The scanning electron microscope has found application in diverse fields of study including biology, chemistry, materials science, semiconductor technology, and many others. In scanning electron microscopy, the secondary electron method. the backscattererd electron method, and the electromotive force method are most widely used, and the transmitted electron method will become more useful. Change-over of magnification can be easily done by controlling the scanning width of the electron probe. It is possible. to continuously vary the magnification over the range from 100 times to 1.00,000 times without readjustment of focusing. Conclusion: With the development of a scanning. electron microscope, it is now possible to observe almost all-information produced through interactions between substances and electrons in the form of image. When the probe is properly focused on the specimen, changing magnification of specimen orientation does not require any change in focus. This is quite different from the conventional transmission electron microscope. It is worthwhile to note that the typical probe currents of $10^{-10}$ to $10^{-12}\;{\AA}$ are for below the $10^{-5}$ to $10^{-7}\;{\AA}$ of a conventional. transmission microscope. This reduces specimen contamination and specimen damage due to heatings. Outstanding features of the scanning electron microscope include the 'stereoscopic observation of a bulky or fiber specimen in high resolution' and 'observation of potential distribution and electromotive force in semiconductor devices'.