• Journal of the korean academy of Pediatric Dentistry
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• v.34 no.3
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• pp.532-542
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• 2007

The purpose of study was to review the transition of dentition according to the evolution of man to know the background of the dental problems like hypodontia and malocclusion. Man is Kingdom Animalia, Phylum Chordata, Class Mammalia, Order Primates, Suborder Haplorrhini, Superfamily Hominoidea, Family Hominidae, Genus Homo, Species Sapiens by taxonomy. The first hominid was Australopithecus which appeared c. 4 millions of years ago and showed bipedalism and distinct dentition. Homos began with H. habilis who appeared c. 2.5 millions of years ago and made stone tools, and then H. erectus and H. neanderthalensis appeared and disappeared until H. sapiens came. The dental formula of primitive mammalians which was I3 C1 P4 M3 changed to I2 C1 P4 M3 of primitive primates, to I2 C1 P3 M3 of Haplorrhini, and to I2 C1 P2 M3 of hominoids. That of H. sapiens is changing to I2 C1 P2 M2.The box type dentition of hominoids changed to the omega type dentition of Australopithecus, and to the parabolic type of H. sapiens. The size of teeth decreased continually, especially the canine and sexual dimorphism. The dentition moved backward and downward to the cranial crown according to the increase of the brain and decrease of the jaws. It was suggested that the change of diet to the starchy foods, food processing, and the development of cooking reduced the necessity of mastication and caused the change of dentition. The future of H. sapiens who is quite a new species in the earth histroy and is now causing the mass extinction of other species is hard to see. It seems that hypodontia and malocclusion are related to the dentition change according to the evolution of man and is likely to increase.

• Applied Chemistry for Engineering
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• v.24 no.4
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• pp.396-401
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• 2013

Alternating copolymers, poly[9-(2-octyl-dodecyl)-9H-carbazole-alt-4,7-di-thiophen-2-yl-benzo[1,2,5]thiadiazole] (PCD20TBT) and poly[9,10-bis-(2-octyl-dodecyloxy)-phenanthrene-alt-4,7-di-thiophen-2-yl-benzo[1,2,5]thiadiazole] (PN40TBT), were synthesized by the Suzuki coupling reaction. The copolymers were soluble in common organic solvents such as chloroform, chlorobenzene, 1,2-dichlorobenzene, tetrahydrofuran and toluene. The maximum absorption wavelength and the band gap of PCD20TBT were 535 nm and 1.75 eV, respectively. The maximum absorption wavelength and the band gap of PN40TBT were 560 nm and 1.97 eV, respectively. The HOMO and the LUMO energy level of PCD20TBT were -5.11 eV and -3.36 eV, respectively. As for PN40TBT, the HOMO and the LUMO energy level of PCD20TBT were -5.31 eV and -3.34 eV, respectively. The polymer solar cells (PSCs) based on the blend of copolymer and PCBM (1 : 2 by weight ratio) were fabricated. The power conversion efficiencies of PSCs based on PCD20TBT and PN40TBT were 0.52% and 0.60%, respectively. The short circuit current density ($J_{SC}$), fill factor (FF) and open circuit voltage ($V_{OC}$) of the device with PCD20TBT were $-1.97mA/cm^2$, 38.2% and 0.69 V. For PN40TBT, the $J_{SC}$, FF, and $V_{OC}$ were $-1.77mA/cm^2$, 42.9%, and 0.79 V, respectively.

• Journal of Christian Education in Korea
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• v.70
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• pp.141-173
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• 2022

The purpose of this study is to illuminate depersonalization in the flow of technological revolution and to present a Christian SARAMDAUM education that aims for a new human image. It represents the Christian SARAMDAUM education that adapts to, mediates, and offers alternatives to the technological and human evolutionary flow of the machine age. The purpose of education for this purpose is to aim for 'Homo Creators', creative human beings presented as a new human image in the age of technological revolution. The educational goal is to nurture creative human beings through creative interpretation, creative integration between disciplines, and personal dialogue in the post-mechanical/ post-conventional paradigm. The content of the education is a conversation with the SARAMDAUM that consiliences the characteristics of post-machine and post-convention. The educational method utilizes Edu-Tech and AIED(Artificial Intelligence in Education) to realize systemic thinking and SARAMDAUM dialogue of technology. In addition, the composition of teachers and learners, educational environment and educational evaluation is presented. The significance of this study is that from the point of view of Christian education, the identity of human beings in the era of the technological revolution has been identified, and research on the creative image of the human being is newly attempted, and the direction of Christian SARAMDAUM education aimed at this is presented. This can be said to be a Christian education that emphasizes the essential characteristics of human beings while accommodating the era of technological revolution.

• Communications of the Korean Institute of Information Scientists and Engineers
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• v.30 no.12
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• pp.71-83
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• 2012

• Journal of the Korean Mathematical Society
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• v.36 no.6
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• pp.1021-1031
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• 1999

In this paper we introduce matrix representations of polygroups over hyperrings and show such representations induce representations of the fundamental group over the corresponding fundamental ring. We also introduce the notion of a polygroup hyperring generalizing the notion of a group ring. We establish homo-morphisms among various polygroup hyperrings.

• Proceedings of the Korean Nutrition Society Conference
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• 2003.05a
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• pp.245.1-245.1
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• 2003

• Proceedings of the Korean Nutrition Society Conference
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• 2003.05a
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• pp.279.2-279.2
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• 2003

• Proceedings of the Korean Nutrition Society Conference
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• 2003.05a
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• pp.245.2-245.2
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• 2003

• Proceedings of the Korean Ceranic Society Conference
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• 2003.10a
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• pp.229.2-229
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• 2003

• International Journal of Reliability and Applications
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• v.4 no.2
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• pp.71-77
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• 2003

We propose, in this paper, the discrete version of NBU$_{Mg}$and show that the NBU$_{Mg}$ class is preserved under both the non-homo geneous poisson shock model and the general shock model.