• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.5 no.4
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• pp.98-107
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• 1996

In order to predict analytically torque, thrust force, tool life and chip formation in drilling, cutting models for chisel edge with various tool-chip contact length were developed in this type. Also, the experimental tests are run with various pilot holes. The following conclusions were obtained from the analysis. \circled1 It's also found experimentally that thrust force(Fz) decreases as pilot hole diameter increases. \circled2 Surface roughness for material(G) is larger that for material(J). The difference over two materials in roughness value about 0.5$mu extrm{m}$. \circled3 Flank wear of the drill in cutting material of G less than any other kinds of materials(F, G, H, I, J). \circled4 In drilling a deep hole on a workpiece over SM45C either twist drill. The chip was conical helix type at the fist suspensely change the two segment type and than two a long pitch helix style.

• Analyses & Alternatives
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• v.4 no.2
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• pp.39-70
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• 2020

This paper examines the changing roles of ownership in the economic growth by using a panel data set of 30 provinces in China for the period (1999-2010). With the use of absolute and relative presence variables, this study shows that private enterprises have emerged as the engine of economic growth in China in the later period (2005-2010). The growing size and number of private enterprises are positively linked to growth. However, though foreign-invested enterprises have been acclaimed as the main contributors to economic growth in China, they have minimal effect on the economic growth in the later period. State-owned enterprises have a significant and negative effect on the economic growth in the later period. The results can be interpreted that the engine of growth in China has been changed over time from other ownerships to private ownership. Private companies have developed a lot in every respect and started to lead the economy for long-run growth. China initiated its economic growth by adopting foreign capital and it is still the top destination for foreign direct investment among developing countries. However, to sustain the growth over a long period, private sector should be of great importance and perform a key role in the view of catch-up economics.

• Proceedings of the Korea Information Processing Society Conference
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• 2008.05a
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• pp.718-720
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• 2008

In this paper, the study focus on continuous query in EPC Information Services(EPCIS) middleware which is a component of RFID system. We can consider EPCIS as a data stream system with a repository. In our work continuous query is implemented in two query execution model. One is standing query model another is traditional query execution model in which continuous query run over database periodically. Furthermore a balance strategy is presented. It is used to determine which continuous query implementation model is suitable for the query. Finally we conclude our work and issue some research topic for future work.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.2606-2611
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• 2003

Comprehensive study on the control system design for a RTP process has been conducted. The purpose of the control system is to maintain maximum temperature uniformity across the silicon wafer achieving precise tracking for various reference trajectories. The study has been carried out in two stages: thermal balance modeling on the basis of a semi-empirical radiation model, and optimal iterative learning controller design on the basis of a linear state space model. First, we found through steady state radiation modeling that the fourth power of wafer temperatures, lamp powers, and the fourth power of chamber wall temperature are related by an emissivity-independent linear equation. Next, for control of the MIMO system, a state space modeland LQG-based two-stage batch control technique was derived and employed to reduce the heavy computational demand in the original two-stage batch control technique. By accommodating the first result, a linear state space model for the controller design was identified between the lamp powers and the fourth power of wafer temperatures as inputs and outputs, respectively. The control system was applied to an experimental RTP equipment. As a consequence, great uniformity improvement could be attained over the entire time horizon compared to the original multi-loop PID control. In addition, controller implementation was standardized and facilitated by completely eliminating the tedious and lengthy control tuning trial.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1107-1114
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• 2005

The running condition of multi-system air conditioner is prone to vary largely as it is designed for individual conditioning in each space of middle and small sized buildings. This leads to overcooling in case of partial load run, while the lack of capacity happens in case of full load run. Besides these, there exist such problems as instabilities due to the uneven refrigerant distribution caused by fluctuation of load and the change in piping line. Based upon the basic study on the function characteristics found in parts needed for maximized system working design in order to troubleshoot, the system functioning pattern should be identified through the different tests with various operating circumstances and the analysis models should be developed. With this ground, the control logic has to be made to have a control over capacity and make possible the efficient distribution of refrigerant.

• Journal of Korean Society of Water and Wastewater
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• v.10 no.3
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• pp.100-114
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• 1996

Besides insufficient water, water contamination confronts us with 'water crises' of both quantity and quality. However, the daily water consumption per capita of Korea is greater than that of other developed countries. Because of the current low water price, which is lower than a half of production cost, not only does it become difficult to cope promptly with rapidly increasing water demand and water contamination, but it also causes waste of water. We should, therefore, switch over from supply side management-oriented policy to demand side management-oriented policy through a raise of the water rate. This study carries out a cost analysis based on fair return method which is the principle of water pricing in Korea, and it estimates, through equilibrium analysis, long run marginal cost(LRMC), which satisfies allocative efficiency and reflects true social cost to additional one-unit water supply. Based on the results, this study proposes that the estimated LRMC is the optimal price level in water pricing, which is the most important of the demand side management policies. In the end, water conservation effect, price pervasive effect, and social welfare effect are analyzed.

• Journal of Environmental Science International
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• v.7 no.1
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• pp.27-35
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• 1998

The present study intends to investigate the transient response of an atmosphere /ocean general circulation model to a gradual Increase of atmospheric carbon dioxide. To detect the climatic change of the for 1% $CO_2$ run with increasing $CO_2$ and the control run with fried $CO_2$ are compared. From response of the surface air temperature due to the gradual increase of atmospheric carbon dioxide is slowly increased with latitudes and is clearly larger over continents than oceans. The annual goffal mean temperature is continuously increased with 0.03552 per one year with strong SIN ratio and distinguished from the natural variability The time dependent response of the gradual increasing $CO_2$ has the strong seasonal variability with small change In summer and large change in winter, and the strong regional In the Asian and the American continents. It has been suggested that the direct and the feedback processes in the climate systems should be investigated by the detailed sensitivity runs to get the meaninguul estimate of the $CO_2$ forced variability.

• Journal of Korean Institute of Industrial Engineers
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• v.28 no.2
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• pp.201-215
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• 2002

In this paper, we use a structural equation model to diagnose success factors on commercialization of information and communication technology considering the characteristics of commercialization process in terms of the type of technology, technology provider and technology receiver. The results of our study indicated the following. The transferor's research ability has significant effects on the commercialization by small businesses with low R&D expenditure to sales ratio, and the business management ability plays an important role in the commercialization by the relatively large (over 100 employees) companies with low R&D expenditure ratio. During the commercialization of the technology independently researched by government run institute or university, the transferee's business management ability is crucial to success. To those companies which run the existing business with high R&D expenditure ratio, their ability to utilize technology is essential. When the independently researched technology is used in the new business, the companies' business management ability and the role of technology transfer center are the important factors on the commercialization. Based on these findings, we suggest some strategies to effectively promote R&D efforts for successful commercialization.

• Korean Journal of Applied Biomechanics
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• v.17 no.4
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• pp.157-167
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• 2007

The purpose of this study was to analyze kinematic techniques in the woman's 100m hurdle. In order to find the kinematic parameters, a 3-D video system for kinematic analysis-kwon3d 3.1(Kwon3D Motion Analysis Program Version 3.1)-was used. Eight JVC video cameras(GR-HD1KR) were used to film the performance of Lee Yeon-Kyoung at a frame rate of 60fields/s. The kinematic characteristics from the first hurdle to last hurdle were analyzed at the clearing hurdle spots such as distance, velocities, heights and angles. The real-life three-dimensional coordinates of 20 body landmarks during each phases were collected using a Direct Linear Transformation procedure. After analyzing the kinematic variables in the 100m hurdle run, the following conclusion were obtained; Lee Yeon-Kyoung had to maintain constant stride lengths between hurdles and increase takeoff distance before clearance and shorter landing distance after clearance. She also had to hit the correct takeoff point in front of the hurdle and extend the lead leg at the moment of landing in order to minimize the loss of velocity. She had to sprint between hurdles as fast as possible over 8m/s and run powerful first stride and shortened third stride preparing for the following hurdle clearances.

• Asia-Pacific Journal of Business
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• v.8 no.2
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• pp.1-14
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• 2017

Initial public offering (IPO) has been well known to be underpriced initially and under-performed in the long run. However, whether an IPO is underpriced or not strongly depends on how to measure the fair value. This paper hand collects data of IPOs newly listed in Korea market when whether IPO is overpriced or not is clearly distinguishable. The overpriced IPO refers to as the one the underwriters buy back after the listing. With the data, the paper examines that IPOs are overpriced and that the characteristics are related to the underpricing at the aftermarket dates and the performance in the long run. The data of clearly overpriced IPOs are little available from other IPO markets like US IPO market. From the data of IPOs listed under the underwriting rule of market stabilization, the results obtainable are the followings. First of all, the average initial return 70% of the underpriced IPO at the aftermarket dates is greater than the one 40% of the overpriced one. The overpriced IPOs are priced highly over the mid prices of the price bands at the pricing dates and then supported by relatively higher subscription rates of individual investors. The probit analyses moreover report that individual investors do not distinguish the overpricing of IPOs from the underpricing. These imply that the overpricing is strongly affected by the underwriting rule on the initial pricing.