• Archives of Craniofacial Surgery
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• v.12 no.1
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• pp.28-32
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• 2011

Purpose: A cranioremodeling helmet for correcting plagiocephaly was recently developed. However, no discrete objective methods to evaluate how the deformity is being corrected have been developed. We have established an easy and cost-effective method that can be used not only to show the correction process, but can also be used by physicians to assess the degree of plagiocephaly two-dimensionally. Methods: For two-dimensional evaluation, a length of malleable memory wire (2 mm in diameter) resembling "Sun-Wukong's headband" was placed on the patient's head. The wire around the patient's head was positioned on a plane including points 1 cm above the eyebrow and 1 cm above the auricle. The wire was placed on a sheet of paper and the outline was marked using pens of various colors during each visit. The degree of plagiocephaly correction could then be shown to the patient's parents at every consultation. Results: The method established by the present study easily shows the horizontal cross-section transformation of the head, illustrates plagiocephaly correction by the helmet, and shows the degree of correction in a two-dimensional manner. Conclusion: A soft-shell helmet is widely used for correcting plagiocephaly. However, evaluating the effectiveness of the helmet has been determined in a subjective manner, and a more objective method is now in demanded. Our study found that a "Sun-Wukong's headband" wire can accurately measure two-dimensional changes. Future studies will be required to identify landmarks needed for assessing plagiocephaly correction.

• Journal of the Korean Institute of Gas
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• v.17 no.6
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• pp.52-57
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• 2013

In this study, the strain energy density, stress and deformation behaviors have been analyzed as functions of a thickness and a force area of protective helmets with and without an extruder on the top of the shell structure using the finite element method. The strain energy density in which is related to the absorption capacity of an impact energy transfer is one of a key element of the helmet safety. The FEM analyzed results show that when the impulsive force of 4,540N is applied on the top surface of the helmets, the maximum stress is linearly reduced for an increased area of impact forces. But, the maximum strain energy density has been reduced for the increased force area. The reduced strain energy density may increase the impulsive forces transferred to the head and neck of helmet wearers, which may decrease the impact energy absorption safety of the helmets. In thus, it is safer design of the helmet in which has an extruded structure on the summit surface, but the modified helmet may decrease the impact energy absorption capacity.

• Korean Journal of Heritage: History & Science
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• v.46 no.1
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• pp.124-139
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• 2013

Choi Cheon-yak(about 1684~1755) is an artist who left the various artistic works such as sculptures of royal tombs, architectures. In addition, he was not only a skilled caster but also an able artisan carving jade in the early Joseon Dynasty period. Starting from making royal seals of King Suk-jong, he had made more than about 40 Royal seals until 1755. Choi Cheon-yak was well known as a skilled jade craftsman. Another of his great abilities was to carve subjects into ideal figures. In virtue of his greater abilities, he could take part in the process of constructing Royal tombs and sculpting the stone statues of military officials' which were erected at aristocrats' tombs. With these accumulated skills, when he was in charge of designing the folding screen stones for King In-jo's Jang Neong, he could even replace 12 animals system and clouds with peonies and lotus. Among his various abilities, his skill in carving a sculpture can stand comparison with any other contemporaries. His sculpture skill was at its zenith in 1752, the stone statues of military officials' at the Ui soseson's tomb count his showpiece that describes a model at the age of his late teens and is a realistic and portrayal sculpture, which met the royal family's dignity. In the same year, the stone statues of military officials' constructed by Choi Cheon-yak was elected in front of the Jo Hyen-myeong's tomb(1690~1752). This masterpiece referred to the armor of those of King Gong-min Neong and newly added a helmet and the patterns of a tortoise shell. These patterns of a tortoise shell were passed down to Park Moon-su's tomb in 1756 and Queen Jeong-sung's Hong Neung by his colleagues : Kim Ha-jeong and Byeon Yi-jin etc. He was one of the greatest sculptors in the $18^{th}$ century. People in Joseon praised him highly for his imaginative work from an amorphous object. Especially, these stone statues of military at Jo Hyeonmyeong's tomb shows the proofs of his supreme artwork.