• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 2002.04a
• /
• pp.649-654
• /
• 2002

In recent days the more use of CFRP composite is in the airplane, automobile, and sport goods , etc., the more necessity of research on it in this engineering. In this research, the CFRP composite specimen are fabricated by 48 CFRP plies with 8 orientation angles, and the specimens are drilled with 3 tools. The results are analyzed with consideration of cutting force, type of tools and fabrication condition. The specimens with each drilling conditions are also investigated with SEM. The optimal drilling conditions such as drill types and cutting fence with respect to the fabricating condition are studied.

• Korean journal of food and cookery science
• /
• v.13 no.2
• /
• pp.113-123
• /
• 1997

Conventional foodservice system has been the most prevalent system across the country. However, all the elementary students throughout the country is not being provided with school lunch program because of the restriction on equipping school foodservice facilities. So commissary foodservice system was introduced to school lunch program in 1991. This study was designed to evaluate condition of existing major equipment including volume, probable useful life, and frequency of use and determine equipment improvements on conventional and commissary school foodservice systems. A questionnaire was developed and mailed to 87 dietians of conventional and 46 dietians of commissary school foodservices in Kyunggi-do. Response rates were 89.1% and 91.3%, respectively . Approximately one third of commissary foodservices were converted from conventional to commissary. Only 52.6% of conventional and 53.5% of commissary foodservice facilities/equipments have been desirable in quality and quantity. Capacity, functional ability, using frequency, and relationship with efficient work management were analyzed according to school foodservice system. Content analysis was conducted regarding to dietitians' opinions on foodservice facilities/equipment.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2007.11a
• /
• pp.702-707
• /
• 2007

A Color Discerning Device(CDD) is the equipment to use in a Rice Processing Complex(RPC). A CDD can sorting discolored grain according to light and shade. The existing a CDD's driving performance is not so good as overseas machine. Besides, transportation process causes a defect in the mechanism from impact or harmonic excitation or etc. This study is represented the problem of CDD through experiment and simulation on a CDD. To analysis the problem of driving condition, devide each part of CDD for performed modal analysis. The problem of driving of driving condition and transportation process solved by carry out modal analysis and static analysis.

• Journal of Korean Society for Quality Management
• /
• v.17 no.2
• /
• pp.64-69
• /
• 1989

This paper aims at analyzing the process capability and at determining an optimal condition by experimental designs using the 2-way classification with repitition in order to maintain lower Nacl content and to refine both of a very small quantity of fatty acid and various magnetic ions in the glycerin to use ion exchange resin treatment process. An optimal condition of each level combination in both of passing temperature of cation exchange resin($A_1$, $A_2$, $A_3$) and of anion exchange resin($B_1$, $B_2$, $B_3$) is $A_3B_3$. The process capability index is improved from 0.63 to 1.40 and is interpreted as a desirable state. This analysis of process capability by experimental designs will contribute to improving productivity and quality of products.

• Journal of Korean Society for Quality Management
• /
• v.43 no.2
• /
• pp.169-184
• /
• 2015

Purpose: This paper is concerned with optimally designing accelerated degradation test (ADT) plans based on a gamma process for the degradation model. Methods: By minimizing the asymptotic variance of the MLE of the q-th quantile of the lifetime distribution at the use condition, the test stress levels and the proportion of test units allocated to each stress level are optimally determined. Results: The optimal plans of ADT are developed for various combination of parameters. In addition, a method for determining the sample size is developed, and sensitivity analysis procedures are illustrated with an example. Conclusion: It is important to optimally design ADT based on a gamma process under the condition that a degradation process should be always nonnegative and strictly increasing over time.

• Journal of the Korean Society for Precision Engineering
• /
• v.21 no.2
• /
• pp.35-42
• /
• 2004

The control systems with friction cause the steady state error and slow response, because friction is a sensitive to the change of system condition and has highly nonlinear characteristics. To overcome these problems and do precise position control for a ball-screw system, we use Coulomb friction estimator and the sliding mode control(SMC) to compensate its negative effect. The applied SMC for tracking position has a characteristics of robust stability and reducing chattering, and is derived from the Lyapunov stability theorem and reaching condition. Compensating the estimated friction torque to the bounded disturbance term of the SMC's equivalent control input, it has a tracking performance better than the PID from the experimental results.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2002.05a
• /
• pp.960-963
• /
• 2002

In recent days the more use of CFRP composite is in the airplane, automobile, and sport goods, etc., the more necessity of research on it in this engineering. In this research, the CFRP composite specimen are fabricated by 48 CFRP plies with 8 orientation angles, and the specimens are drilled with 3 tools. The results are analyzed with consideration of cutting force, type of tools and fabrication condition. The specimens with each drilling conditions are also investigated with SEM. The optimal drilling conditions such as drill types and cutting force with respect to the fabricating condition are studied.

• Journal of the Korean Society for Precision Engineering
• /
• v.17 no.12
• /
• pp.54-60
• /
• 2000

Research about tool condition monitoring has been done until now for product automation and unmaned system. But it is hard to apply it to the industrial field due to its cost and reliability. This paper presents the new method of tool wear measurement using Marpos gauge. This is a kind of touch sensor, so its cost is lower than vision system. And it is not affected by dust and illumination, which are important in vision system. This proposed method use tool clearance angle to measure flank wear. Experimental results compared with vision system shows that this method is available for tool condition monitoring system.

• Korean Journal of Weed Science
• /
• v.8 no.2
• /
• pp.141-155
• /
• 1988

We have large areas of forests in our country where various types of trees can grow. Since Japan geographically locates on a wide region with the extention of 3,000 km south and north, the climate varies from subtropical to subarctical one. Many mountains additionally make the climatic condition more complicated. Thus, we are able to see many kinds of trees in our forest areas. We have also frequent rainfalls through whole season and the precipitation reaches approximately 1,500 mm per year in many forests areas. In some rainy regions, it sometimes account for more than 2,000 mm. The condition is so advantageous for the growth of weeds and shrubs that it makes them very strong competitors with plantation trees in our forestries. It, therefore, may be said that the most important problem in Japanese forestries is to combat with undesirable vegetations continuously and to keep trees from weeds.

• Korean Journal of Hydrosciences
• /
• v.4
• /
• pp.21-32
• /
• 1993

The estimates of both runoff depth and peak runoff by the basin runoff curve numbers, which are CN-II for antecedent moisture condition- II and CN -III for antecedent moisture condition-III, obtained from hydrological soil-cover complexes of 26 watersheds are investigated by making use of the observed curve numbers, which are median curve number and optimum curve number, computed from 250 rainfall-runoff records. For gaged basins the median curve numbers are recommended for the estimation of both runoff depth and peak runoff. For ungaged basin, found is that for the estimate of runoff depth CN-II is adequate and for peak runoff CN-II is suitable. Also investigated is the variation of the runoff curves during storms. By the variable runoff curve numbers, the prediction of runoff depth and peak runoff can be improved slightly.