• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.993-997
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• 1998

This paper presents a two-switch boost chopper with a sinewave current shaping and power factor correction scheme, which is applied for driving electronic ballast using high frequency resonant inverter. A working principle of the proposed one-converter type electronic ballast with power factor correction and active filtering schemes is described on the bases of the equivalent circuit of each operation mode, together with operation analysis. The steady-state performance evaluations of this electronic ballast are illustrated and discussed in experiment.

• 중국학논총
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• no.66
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• pp.161-188
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• 2020

The purpose of this paper is to analyze the debate on the Lewisian turning point in China. Despite the heated debate and accumulating research results both inside and outside China, the results showed a very complex spectrum. Different results were presented depending on which criteria the researcher selected, which analytical tools were used, and which data were utilized. Territory of China is vast, and the differences in economic basement and development stages between regions are not only severe, but also the economic gap among areas in a region is big. Therefore, it is difficult to have a significant meaning in analyzing the Lewisian Turning Point China as a whole. In addition, China's industrial production and labor force structure remain very unbalanced. This can be said to be due to the fact that the allocation and relocation of labor force according to the stage of economic development has not been achieved reasonably, and so it confuses the task of determining whether the Lewis Turning Point has arrived of not.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.27 no.4
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• pp.321-329
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• 2001

To establish systematic diagnosis and treatment planning of dentofacial deformity patient including facial asymmetry or hemifacial microsomia patient, comprehensive analysis of three dimensional structure of the craniofacial skeleton is needed. Even though three dimensional CT has been developed, landmark identification of the CT is still questionable. In recent, a method for correcting cephalic malpositioning that enables accurate superimposition of the landmarks in different stages without using any additional equipment was developed. It became possible to compare the three-dimensional positional change of the maxillomandible without invasive procedure. Based on the principle of the method, a new program was developed for the purpose of diagnosis and treatment planning of dentofacial deformity patient via three dimensional visualization and structural analysis. This program enables us to perform following menu. First, visualization of three dimensional structure of the craniofacial skeleton with wire frame model which was made from the landmarks observed on both lateral and frontal cephalogram. Second, establishment of midsagittal plane of the face three dimensionally, with the concept of "the plane of the best-fit". Third, examination of the degree of deviation and direction of deformity of structure to the reference plane for the purpose of establishing surgical planning. Fourth, simulation of expected postoperative result by various image operation such as mirroring, overlapping.