• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.05a
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• pp.159-165
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• 2004

The shrinkages of injection molded parts are different in molding operational conditions and mold design. It also differs from resins. The shrinkages of injection molded parts for PBT (polybutylene terephthalate), PC (polycarbonate),and glass reinforced PBT and PC have been studied for various operational conditions of injection molding. The part shrinkage of crystalline polymer, PBT was higher than that of amorphous polymer, PC by about two times. The part shrinkages of both polymers decreased as glass fiber content increases. Higher Injection temperature and lower injection pressure resulted in a higher shrinkage in both PBT and PC resins. As mold temperature increases the part shrinkage of PC decreased. However, the part shrinkage of PBT increased as mold temperature increases. The part shrinkage of both PBT and PC resins decreased as gate size increases since the pressure delivery is mush easier for a larger gate size. The part shrinkage of flow direction was less than that of the perpendicular direction to the flow for both pure and glass fiber reinforced resins. The part shrinkage at the position close to the gate was less than that of the position far from the gate.

• Journal of Ginseng Research
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• v.25 no.2
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• pp.82-88
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• 2001

This study was carried out to investigate a point of difference between normal and inferior Korean red ginseng (Naeback red ginseng = red ginseng with white part of clear boundary in phloem and/or xylem of ginseng body, saengnaeback red ginseng red ginseng with white part of indistinct boundary). White part with clear or indistinct boundary in center of ginseng body was observed in inferior red ginseng (naeback and saengnaeback red ginseng), and the differences in the internal color intensity was also found with naked eye. In hunter color values of normal and inferior parts of red ginseng in accordance with particle size, L value was increased with a diminishment in particle size, while a and b value were decreased. Absorbance at visible spectrum did not differ from water and 70% ethanol extract from normal and inferior parts of red ginseng, but absorbance in UV spectrum of extract from naeback part showed higher than those of normal and saengnaeback part. In comparison of intrastructure by electron microscope, the horizontal and vertical section of cortex and pith layer from normal part showed the very dense state, but small holes were found in naeback part of red ginseng by naked eye and electron microscope. The specific surface area of normal, naeback and saengnaeback part appeared 3.02, 3.33 and 6.55 ㎡/g, respectively. From above results, we consider saengnaeback red ginseng is red ginseng in the intermediate process which normal red ginseng changes to naeback red ginseng.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.207-212
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• 2017

Korean civil airworthiness requirements of powerplant system are regulated on KAS Part 23 and Part 33. These are equivalent to FAR Part 23, Part 33 of FAA and CS-23, CS-E of EASA. FAA and EASA rewrites entire airworthiness requirements for the small airplane. It changed current 'prescriptive regulation' into 'performance-based regulation' which makes the object of safety performance. Powerplant requirements are also changed extensively by these concept revolution. In accordance with reorganization, we studied new powerplant system requirements of FAR Part 23 and proposed ideal direction to rewrite of Korean Airworthiness Standard rewrite.

• Transactions of Materials Processing
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• v.13 no.6 s.70
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• pp.515-521
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• 2004

The shrinkages of injection molded parts are different in molding operational conditions and mold design. It also differs from resins. The shrinkages of injection molded parts fur PBT (polybutylene terephthalate), PC (polycarbonate), and glass reinforced PBT and PC have been studied for various operational conditions of injection molding. The part shrinkage of crystalline polymer, PBT was higher than that of amorphous polymer, PC by about two times. The part shrinkages of both polymers decreased as glass fiber content increases. Higher injection temperature and lower injection pressure resulted in a higher shrinkage in both PBT and PC resins. As mold temperature increases the part shrinkage of PC decreased. However, the part shrinkage of PBT increased as mold temperature increases. The part shrinkages of PBT and PC resins decreased as gate size increases since the pressure delivery is mush easier for a larger gate size. The part shrinkage of flow direction was less than that of the perpendicular direction to the flow for both pure and glass fiber reinforced resins. The part shrinkage at the position close to the gate was less than that of the position far from the gate.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.10
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• pp.887-894
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• 2016

The CNG pressure vessel is manufactured by a deep drawing and ironing (D.D.I) process for forming cylinder parts, followed by a spinning process for formation of the dome part. However, studies on the buckling phenomenon of the dome part and formation of the inlet part have not been performed yet, and the CNG pressure vessel is produced by the experience of the field engineers and the trial and error method. In this study, buckling phenomenon during the spinning process was predicted by comparing critical buckling loads obtained through theoretical analysis with axial loads from the FEA, and a method for preventing buckling of the dome part was proposed by employing commercial software (Forge NxT 1.0.2). Also, to form the inlet part, forming loads of the roller at contact point between the roller and the dome part were analyzed according to radii of the dome part, and the inlet part was formed by controlling the radius of the dome part.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.5
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• pp.775-783
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• 1990

In this paper we implemented the fast thinning unit by modifying the pipeline architecture which was proposed by Stanley R. Sternberg. The unit is useful in preprocessing such as image representation and pattern recognition etc. This unit is composed of interface part, local memory part, address generation part, thinning processing part and control part. In thinning processing part, we shortened the thinning part which performed by means of look up table using window mapping table. Thus we improved the weakness of SAP, in which the number of delay pipeline and window pipeline are equal to image column size. Two independent memorys using tri-state buffer enable the two direction flow of address generated by address generation part. This unit avoids the complexity of architecture and has flexibility of image size by means of simple modification of logic bits.

• Journal of Korean Institute of Industrial Engineers
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• v.20 no.3
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• pp.55-63
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• 1994

Optional two-part tariffs are in growing use in telecommunication services markets. This paper considers the problem of designing profit-maximizing optional two-part tariffs for heterogeneous user groups. It is shown that, at an optimum, one of usage charges among a set of optional two-part tariffs should be made equal to marginal cost. It is also shown that, if demand curves cross, then one of usage charges at the optimum can be below marginal cost. An example with linear demand functions is given to illustrate the important features of optimal two-part tariffs.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.9 no.1
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• pp.68-74
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• 2000

The STL file format is an approximation of 3-D model with triangular facets. STL is a standard input file format of Rapid Prototyping(RP) equipment In computer graphics a circle has been approximated with an inscribed polygon which causes an error between the real and approximated circles. In this study an intersecting polygon has been used to approximate the circle and applied to produce more accurate RP part. The newly proposed method shows it's excellence in part accuracy.

• Journal of Korean Medical classics
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• v.27 no.1
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• pp.47-56
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• 2014

Objective : The aim of this study is to find out the significance of Chongu pulse diagnosis as the standard of measuring the result of the acupuncture on 'the affected part of the pulse wave' based on the literature. Method : (1) The clear concepts of the 'unaffected part' and the 'affected part' were organized. (2) The relation between the pulse diagnosis and the acupuncture in Hwangjenaekyung was studied. (3) The indications of Mu acupuncture treatment(繆刺法) and Geo acupuncture treatment(巨刺法) in Hwangjenaekyung was studied. (4) The types and changes of pulse diagnosis in Hwangjenaekyung was studied, especially based on the relation between Sambuguhu pulse diagnosis(三部九候脈診) and Chongu pulse diagnosis(寸口脈診). (5) By synthesizing these results, the significance of Chongu pulse diagnosis as the standard of measuring the result of the acupuncture on 'the affected part of the pulse wave' was found. Result & Conclusion : 1. When the affected part and the unaffected part are defined, it is necessary to make clear that which one of next three definitions is used ; Firstly, 'the broad sense of definition of the affected part and the unaffected part of the symptom', which contains the pulse wave. Secondly, 'the narrow sense of definition of the affected part and the unaffected part of the symptom', without the pulse wave. And thirdly, 'the definition of the affected and the unaffected part of the pulse wave', which has the only independent standard of the pulse wave. 2. Geo acupuncture treatment(巨刺法) is an acupuncture treatment which means the needling on 'the affected part of the pulse wave' based on Sambuguhu pulse diagnosis (三部九候脈診), and Mu acupuncture treatment(繆刺法) is an acupuncture treatment which means the needling on 'the unaffected part of the symptom based on the narrow sense of the definition'. The range of the indications of Mu acupuncture treatment(繆刺法) and Geo acupuncture treatment(巨刺法) contains most of the diseases which contains Rakbyung(絡病), Kyungbyung(經病) and Ojangbyung(五臟病). 3. Chongu pulse diagnosis(寸口脈診) contains not only the range of the indications of Sambuguhu pulse diagnosis(三部九候脈診), but also most of the diseases. 4. From synthesizing these results of the study on the literature, we infer that Chongu pulse diagnosis as the standard of measuring the result of the acupuncture on 'the affected part of the pulse wave' is significant.

• Journal of Korean Society for Quality Management
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• v.18 no.2
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• pp.9-17
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• 1990

This paper deals with a FOQ( ; fixed-order quantity) model for spare-part inventory control. In a spare-part inventory problem, stock depletion arises not from external market demand but from internal demand resulting from failures of parts in use. The problem differs from the classical inventory problem in that the demand for a failed part never arises more during stockout period, since the unit remains inoperative when stockout occurs until the failed part is replaced by new one. In the problem under consideration, n identical units are operating simultaneously and failed one is replaced immediately by new one if on-hand spares remain. In order to replenish spares, an order with quantity Q is placed whenever the number of on-hand spares falls to levels. The average annual cost of operating the spare-part inventory system is derived under the assumption that both lifetime of a part and replenishment lead-time distributions are exponential.