• Proceedings of the Korean Operations and Management Science Society Conference
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• 1996.04a
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• pp.324-327
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• 1996

In this paper, the affecting factors of the access demand for the cellular service are derived, and the access demand function of the cellular service is estimated. The results obtained in this study are as follows: First, the price (access charge) and the income elasticities of cellular services there exists a network externality in cellular communication services. Third, the technological capability of the service provider has played an essential role in expanding the size of subscribers. Fourth, the access demand of cellular communication service is not sensitive to the usage charge. According to the above results, it can be inferred that if the access charge is lowered, the number if subscribers will increase to the critical mass, and then the cellular communication market will grow up to a saturation point naturally.

• Journal of the Korean Operations Research and Management Science Society
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• v.23 no.4
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• pp.63-73
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• 1998

With the success of flexible manufacturing systems(FMSs), flexible assembly systems(FASs) have been developed to automatic factories further. As in a cellular FMS, a celluar FAS is considered as the most flexible and feasible assembly systems configuration. This paper presents a method for the integrated layout design in cellular FASs. Unlike the traditional paper, this paper deals with the formation of cells and the layout of cells for jobs with operation times on different machines. The procedure in this paper consists of two distinct phases. The first phase presents machine arrangement in a double rows flowline. cell formation not to allow intercellular movements, and integrated layout design in cellular FASs considering the characteristics of FAS, layout, and production factors This phase uses older optimal algorithm. The second phase proposes to balance the system with an objective of reducing the degree of workload deviation in the cells. Simulated annealing method is used to balance the system. This phase also shows the integrated layout design in cellular FASs with the cost less than total cost of the first phase.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1996.04a
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• pp.333-336
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• 1996

This paper is an exploratory study aimed at finding factors that influence the penetration of cellular mobile telecommunications which have seen rapid development since 1980s. The paper tries to find economy and policy variables to influence the penetration by means of the multiple regression analysis. This paper shows a model that explain the penetration ratio of cellular service. The model is based on data from 39 upper middle income and 39 high income countries. The result shows that GDP per capita and the service period of the cellular mobile telecommunication have influenced on the penetration ratio positively, and the tariff of the service negatively. But, it is the open area to study the impact of the telecommunications policy changes on penetration, and to set a model which could explain the nation-specific characteristics.

• BMB Reports
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• v.33 no.1
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• pp.59-62
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• 2000

Hepatitis C virus (HCV) nonstructural 5B (NS5B) protein is an RNA-dependent RNA polymerase (RdRp). To determine whether it can contribute to viral replication by interaction with cellular proteins, the yeast two-hybrid screening system was employed to screen a human liver cDNA library. Using the HCV NS5B as a bait, we have isolated positive clones encoding a cellular protein. The NS5B interacting protein, 5BIP, is a novel cellular protein of 170 amino acids. Interaction of the HCV NS5B protein with 5BIP was confirmed by a protein-protein blotting assay. Recently, we have demonstrated that NS5B possesses an RdRp activity and thus it is possible that 5BIP, in association with NS5B, plays a role in HCV replication.

• Journal of Physiology & Pathology in Korean Medicine
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• v.22 no.4
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• pp.802-809
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• 2008

Gamijangsing-tang (GMJST) has been used for treatment of bone formation in traditional korean medicine. The purpose of this study is to examine effects of GMJST on bone metabolism. The effects on the osteoblasts were determined by measuring (1) cell proliferation, (2) alkaline phosphatase (ALP) activity, (3) osteoprotegerin (OPG) secretion. (4) The morphologic changes of cells were observed by light microscopy and electron microscopy. Mineralization of calcium was determined by quantitative alizarin red-S assay and mineralization of phosphate was observed by von kossa staining. The morphologic changes of mineralization on the cells were observed by transmission electron microscopy (TEM). The effects on the osteoclast were investigated by tartrate-resistant acid phosphatase (TRAP) staining. Following results were obtained: Celluar activity of osteoblastic cells (MG-63) was significantly increased in 10-5 of dilution of GMJST. ALP and OPG activity of osteoblastic cells were increased in GMJST than normal MG-63 cell. Mineralization of osteoblastic cells were increased in GMJST than normal MG-63 cell. The activity of osteoclast cells (RAW 264.7) was significantly decreased in GMJST than normal MG-63 cell. From the results, GMJST stimulated the proliferation and mineralization of bone-forming osteoblast and inhibited by bone- lysis osteoclast.

• Tuberculosis and Respiratory Diseases
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• v.63 no.2
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• pp.165-172
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• 2007

Background: The pathogenesis of lung cancer includes the accumulation of multiple genetic abnormalities. The CREB-binding protein(CBP) is one of several transcriptional co-activators among various sequence-specific DNA-binding transcription factors. CBP is involved in a wide range of cellular activities, such as DNA repair, cell growth, differentiation, and apoptosis that are suspected of contributing to tumorigenesis. The goal of this study was to evaluate CBP expression in a series of human lung tissues containing normal epithelium, premalignant lesions(hyperplasia and dysplasia) and squamous cell carcinomas. Materials and Methods: Immunohistochemical staining was performed on formalin-fixed paraffin-embedded sections by use of a monoclonal anti-CBP antibody. CBP expression was compared in samples from 120 patients with premalignant and malignant histological types including 20 metaplastic specimens, 40 dysplastic specimens, and 60 squamous cell carcinomas in the lung. Results: CBP expression was seen in 35% (7/20) of the metaplastic specimens. 65% (26/40) of the dysplastic specimens, and 70% (42/60) of the squamous cell carcinomas (p<0.05). According to celluar atypism, CBP expression was 50% (10/20) of the low-grade dysplastic specimens and 80% (16/20) of the high-grade dysplastic specimens(p <0.01). By cellular differentiation, CBP expression was seen in 95% (19/20) of the well differentiated squamous cell carcinomas, 85% (17/20) of the moderately differentiated carcinomas and 30% (6/20) of the poorly differentiated lesions (p <0.05). Conclusion: These results suggest that CBP may have an important role in malignant transformation of precancerous lung lesions and may be a marker for malignancy.