• 한국정밀공학회지
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• 제17권9호
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• pp.53-61
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• 2000

The manufacture of a marine propeller typically requires long lead time to generate 5-axis tool path. Hence it may take several weeks to manufacture a satisfactory propeller with a general purpose CAD/CAM system. In this research a dedicated 5-axis CAD/CAM system for machining marine propellers has been developed, The system employs various methods to enhance the productivity : interference-free tool path generation employing check vectors and optimum cutter size determinants. In addition an iterative NURBS modeling technique is used to improve the accuracy of the modeled surface and effective cutting conditions are determined and recommended empirically to increase the productivity. The proposed CAD/CAM system has been implemented with C++ and OpenGL graphic library on the Windows system. The system validation and sample results are also given and discussed.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2004년도 추계학술대회 논문집
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• pp.500-504
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• 2004

The bio-micro pin has been usually used for the biochemistry analysis. The manufacturing capability of the micro-pin and the their array with the effective and low-cost way is very important and it gives great economical benefits to developers. The micro-pin is composed of the sample channel for holding the liquid with the fixed volume, the flat tip which determines the printing quality and the pin head for preventing the rotation of the pin in the holder. In this study, we have manufactured newly designed micro-pins by the wire-EDM process with special jigs, and analyzed liquid holding and printing characteristics with respect to the variation of the shape and the tip size of the micro-pin.

• International Journal of Quality Innovation
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• 제2권1호
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• pp.69-86
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• 2001

The economic design of control charts has been researched for over four decades since Duncan proposed the concept in 1956. Few studies, however, have focused attention on the economic design of a moving average (MA) control chart. An MA control chart is more effective than the Shewhart chart in detecting small process shifts [9]. This paper provides an economic model for determining the optimal parameters of an MA control chart with multiple assignable causes and two failures in the production process. These parameters consist of the sample size, the spread of the control limit and the sampling interval. A numerical example is shown and the sensitivity analysis shows that the magnitude of shift, rate of occurrence of assignable causes and increasing cost when the process is out of control have a more significant effect on the loss cost, meaning that one should more carefully estimate these values when conducting an economic analysis.

• 분석과학
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• 제5권2호
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• pp.217-222
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• 1992

수은침투법을 이용하여 AIN의 이장성형체와 건조가압성형체의 기공구조 해석을 시도하였다. 좁은 기공크기 분포와 높은 충진밀도를 가진 이장성형체에서 소결도가 높고 2차상의 분포가 균일하였다. 수은침투법에 의한 기공크기 분포 해석은 잉크병 현상이 없을 때만 유효하지만 정량미시 분석과의 비교결과 기공률의 측정은 개기공 상태이면 유효함을 보였다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.I
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• pp.374-377
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• 2005

We proposed a new fabrication method for stable flexible LCDs using stamping method with durable elastomer such as poly(dimethylsiloxane) (PDMS). In the device, the LC molecules are isolated in pixels where LCs are surrounded by PDMS microstructure, and two substrates are tightly attached by phase separated polymer layer. The electro-optic characteristics of our cell are comparable to those of normal sample without PDMS microstructure. We propose cost-effective roll-to-roll process for large size of plastic LCDs with our method.

• PNF and Movement
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• 제16권1호
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• pp.1-6
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• 2018

Purpose: Myofascial release (MFR) is an effective treatment for improving muscle stiffness and balance in neurological patients. This study examined long-term effects of MFR on the balance ability of stroke patients. Methods: MFR using a tennis ball was applied to the lower extremity and sacroiliac joint of the affected side of four stroke patients. The four subjects performed the Berg balance scale (BBS) and Timed up and go (TUG) test at the beginning of an 8-week intervention, directly after the intervention, and 2 years later. Results: The BBS scores indicated a trend toward maintenance of balance (p=0.05), but there was no difference in the TUG time (p=0.47). Conclusion: MFR may be a clinically meaningful intervention to maintain balance in stroke patients over a long period. However, the sample size in this study was too small to draw general conclusions. A larger study with more participants is needed.

• 복식문화연구
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• 제7권4호
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• pp.155-167
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• 1999

The present study investigated various sales training programs used by apparel companies and compared each other in order to provide an important information for developing effective training programs for professional salesperson. Sixty eight companies were used and grouped into four categories based on brand characteristics : domestic national brand(DNB), casual brand(CB), foreign brand(FB) and domestic designer brand(DDB). Data were collected from the managers in charge or training salesperson by both questionnaires and personal and telephone interviews. Data were collected during July in 1998, and analyzed by using ANOVA, Duncan\`s multiple range test, and Chi-square test. Since the sample size was small, Yates\` correction formula was used to maximize statistical validity in non-parametric procedure of Chi-square test. The main purpose of sales training indicated by the companies were to satisfy customers and to maximize the profit. Significant differences were found among the groups in the importance level of training contents such as knowledge, and customer relation, training methods, place, and duration/frequency of training at training center.

• 한국안전학회지
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• 제16권4호
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• pp.115-122
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• 2001

Recently construction enterprises involves more occurred with increase of size and complxity of construction works. Risk management is one of the key project management process. Numerous tools are available to support the various phases of the risk management process. We present the results of a study designed to identify the tools that are most widely used and those that are associated with successful project management in general, and in effective project risk management in particular. The study is based on a questionnaire administered to a sample of project managers from construction enterprises. The response data was analyzed in order to find which tools are mon likely to be used in the those organizations that report better project management performance and in those that value the contribution of risk management processes.

• 제어로봇시스템학회논문지
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• 제22권4호
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• pp.247-252
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• 2016

In this paper, we propose a new defect detection technology for micro-defect on the surface of steel products. Due to depth and size of microscopic defect, slop of surface and vibration of strip, the conventional optical method cannot guarantee the detection performance. To solve the above-mentioned problems and increase signal to noise ratio, a novel retro-schlieren method that consists of retro reflector and knife edge is proposed. Moreover dual switching lighting method is also applied to distinguish uneven micro defects and surface noise. In proposed method, defective regions are represented by a black and white pattern. This pattern is detected by a defect detection algorithm with Gabor filter. Experimental results by simulator for sample defects of cold rolled steel show that the proposed method is effective.

• KDI Journal of Economic Policy
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• 제43권4호
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• pp.23-44
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• 2021

This research attempts to provide an in-depth analysis of the public perceptions of inter-Korean economic cooperation. KDI survey data with a sample size of 1,000 were subjected to empirical analyses. By means of ordered logit estimations, we derive the following results. First, there is a significant effect of age on economic cooperation perceptions, where younger generations tend to be more negative. Second, the group who has positive view on the economic cooperation tends to prefer large-scale, domestic-entity-funded cooperation projects, whereas the group who has negative view tends to prefer small-scale projects and projects funded by international organizations. According to these results, prioritizing trade with the involvement of international organizations is likely to be an effective measure to alleviate potential political constraints and to achieve sustainable long-run economic cooperation systems when pursuing the economic cooperation.