• The Journal of Advanced Prosthodontics
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• 제14권2호
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• pp.122-132
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• 2022

PURPOSE. This in-vitro analysis aimed to compare the intaglio trueness, the antagonist's wear volume loss, and fracture load of various single-unit zirconia prostheses fabricated by different manufacturing techniques. MATERIALS AND METHODS. Zirconia crowns were prepared into four different groups (n = 14 per group) according to the manufacturing techniques and generations of the materials. The intaglio surface trueness (root-mean-square estimates, RMS) of the crown was measured at the marginal, axial, occlusal, and inner surface areas. Half of the specimens were artificially aged in the chewing simulator with 120,000 cycles, and the antagonist's volume loss after aging was calculated. The fracture load for each crown group was measured before and after hydrothermal aging. The intaglio trueness was evaluated with Welch's ANOVA and the antagonist's volume loss was assessed by the Kruskal-Wallis tests. The effects of manufacturing and aging on the fracture resistance of the tested zirconia crowns were determined by two-way ANOVA. RESULTS. The trueness analysis of the crown intaglio surfaces showed surface deviation (RMS) within 50 ㎛, regardless of the manufacturing methods (P = .053). After simulated mastication, no significant differences in the volume loss of the antagonists were observed among the zirconia groups (P = .946). The manufacturing methods and simulated chewing had statistically significant effects on the fracture resistance (P < .001). CONCLUSION. The intaglio surface trueness, fracture resistance, and antagonist's wear volume of the additively manufactured 3Y-TZP crown were clinically acceptable, as compared with those of the 4Y- or 5Y-PSZ crowns produced by subtractive milling.

• 기술경영경제학회:학술대회논문집
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• 기술경영경제학회 1997년도 제12회 동계학술발표회 논문집
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• pp.133-158
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• 1997

This paper analyzes the characteristics of technological knowledge flow-structure of Korean manufacturing in dynamic perspective. In doing that, the concept of the knowledge network is introduced which is defined as a set of industries and their interaction(knowledge flow) or linkage. The analysis of the inter-industrial knowledge flows is based on the technological similarity by using R&D researchers'academic background in the year of 1984, 1987, 1990. The analysis is carried out by such methodology as network analysis, indicator analysis and simple statistical analysis. And the final results are drawn both in absolute terms(dimension effect) and in relative terms (proportion effect) respectively. The main findings are as follow. First, the Korean manufacturing knowledge network appears to strengthen existing inter-industrial knowledge linkages rather than to construct new linkages. Second, the network seems to form a dualistic structure in that some high-technology sectors (knowledge production sectors) emerge along with traditional sectors (knowledge absorbing sectors). Third, since the mid-1980s, an inter-industrial fusion is witnessed among technologically intensive sectors, indicating that some sophisticated innovation modes are emerging in Korean manufacturing system.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2006년도 춘계학술대회 논문집
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• pp.395-398
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• 2006

Forging is applied for many industrial fields. Also, it is applied to hose nipple. Stress and metal analysis is finding method of forging possibility and we predict this possibility by finite element forging analysis. But there are also many manufacturing procedure after forging, and metal texture is varied by additional heat treatment or coating. So this research is focused on the measuring and analysis of plastic residual stress distribution at overall manufacturing procedure. From raw material to final product we measured real residual stress at each manufacturing procedure by X ray diffract meter, and simulated another procedure except forging by nonlinear finite element analysis. Also we showed how Zn-Ni coating is more contributable to metal strength than Zn coating. By this research we make final conclusion that process analysis must be observed from raw material to final manufacturing state for robust design.

• Design & Manufacturing
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• 제18권2호
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• pp.51-56
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• 2024

In this study, a tool was developed for analyzing production lead time in turning operations. It is expected to help to reduce machining time and to identify, for example, tool change intervals. The tool was developed using Visual Basic.Net and features a user-friendly graphical user interface (GUI) that allows users to easily input cutting conditions and calculate the usage time and feeding distance for each cutting tool based on a G-code program. Object-oriented programming techniques were also used to encapsulate and classify complex logic, thereby efficiently organizing and managing the functions and data structures of this analysis tool. The analysis tool provides various outputs. It calculates the use time of each detailed process of the turning operation, the use time of each tool, the use time of each type of feeding, and also generates the data needed for cutting time analysis, which can be visualized in charts. The analysis tool developed in this study is expected to significantly contribute to improving the efficiency of manufacturing processes and increasing productivity, particularly, in the manufacturing of components requiring massive material removal, such as aircraft parts.

• Journal of Information Technology Applications and Management
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• 제20권3_spc호
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• pp.169-185
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• 2013

In this research, for find out how operations efficiency for ERP systems, after introducing ERP to manufacturing firms with DEA technique. According to research analyzed relative time dependent efficiency, using Time Window Analysis. And for company group and the other firm within the each same Industry, the relative effectiveness of each company group establishment was compared using DEA.

• 한국연초학회지
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• 제23권1호
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• pp.53-59
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• 2001

To decrease of deviations from target specifications and excessive variability around targe, we exclusively designed statistical process control system involving general manager and expert tool for cigarette manufacturing process. This system is a unique programming environment for the development of total process control software including various control charts according to data type and process capability analysis. Also this system includes the statistical analysis module to analyze defective causes immediately when inferior products are made and the module to offer regular reports. This system is customized considering the manufacture environment based on the opinions of workers.

• 한국기계가공학회지
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• 제11권1호
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• pp.20-25
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• 2012

A Crankshaft multi grinding machine is developed for manufacturing of high precision crankshaft. The grinding head part of the developed machine should be moved precisely during grinding of work materials. In this paper, structural and modal analysis for the crankshaft multi grinding machine is carried out to check the design criteria of the machine. The analysis is carried out by FEM simulation using the commercial software. The machine is modeled by placing proper shell and solid finite elements. The results of structural and modal analysis confirmed that the structural characteristics of grinding machine and the structural safety are considered secure.

• International Journal of Aerospace System Engineering
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• 제4권2호
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• pp.1-4
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• 2017

This work dealt with design and manufacturing of WIG vehicle wing using carbon/epoxy composite materials. In this study, structural design and analysis of carbon composite structure for WIG craft were performed. Firstly, structural design requirement of wing for WIG vehicle was investigated. After structural design, the structural analysis of the wing was performed by the finite element analysis method. It was performed that the stress, displacement and buckling analysis at the applied load condition. And also, manufacturing of subscale wing using carbon/epoxy composite materials was carried out. After structural test of target structure, structural test results were compared with analysis results. Through the structural analysis and test, it was confirmed that the designed wing structure is safety.

• Composites Research
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• 제32권5호
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• pp.249-257
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• 2019

In this paper, the buckling behavior of triaxially braided circular arch with monosymmetric open section subjected to three-point bending was studied experimentally and numerically. First, test specimens were manufactured using vacuum assisted resin transfer molding (VARTM). Then the specimen was tested under three-point bending to determine the ultimate buckling strength. Before performing the numerical analysis, effective material properties of the braided composite were obtained through micro-meso scale analysis virtual testing validated with available test results. Then linear buckling analysis and geometrically non-linear post buckling analysis, established to simulate the test setup, were performed to study the buckling behavior of the composite frame. Analysis results were compared with experimentally obtained ones for verification. The effect of manufacturing defects of tow misalignment, irregular surface and resin rich region, and uncertainties during test setup were studied using numerical models. From the numerical analyses performed it was observed that both manufacturing defect and uncertainties had effect on the buckling behavior and strength.

• 한국자동차공학회논문집
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• 제11권6호
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• pp.118-126
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• 2003

Digital Manufacturing is a technology facilitating effective developments and agile productions of the product via digital computer models representing physical and logical schema and the behavior of the real manufacturing systems including manufacturing resources, environments and products. For the successful application of this technology, a digital factory as a well-designed and an integrated environment is essential. In this paper, we constructed the sophisticated digital factory of a Korean automotive company's body shop, and conducted precise simulations of unit cell, lines and the whole factory for the collision check, the production flow analysis and the off-line programming. We expect that this digital factory of the body shop helps us achieve great savings in time and cost for many manufacturing preparation activities of the new car development.