• 한국정밀공학회지
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• 제15권7호
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• pp.18-25
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• 1998

A prototyping process based on the technique of selective ${\CO_2}$ laser sintering has been carried out using bronze powder. The integration of a ${\CO_2}$ laser and a working table to create the opto-mechanical system has been constructed for making the multi-layer sintering. Three dimensional rapid prototyping process which has used the 40W ${\CO_2}$ laser and bronze powder has been investigated experimentally The optimal scanning method has been found to minimize the deflection and distortion by using the thermal strain method which the laser scans in the x and v directions repeatedly. The method of spreading powder has been improved by using the rubber knife of which the flexibility causes less wave of spreading powder.

• Journal of Advanced Research in Ocean Engineering
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• 제1권3호
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• pp.148-156
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• 2015

Deck plates of ships or offshore structures would make out-of-plane distortion for their thin thickness. These distortions are usually straightened by thermal straightening such as flame heating method. After thermal straightening, the blocks are lifted and moved by cranes to assemble it at dry-dock stage. After this lifting process, out-of-plane deformation again happens frequently. And then, they continuously cause quality and accuracy problems in the final dry-dock process. So, it takes more time for repair and correction working. According to preceding research, the lifting process by cranes would offset the effect on thermal straightening. The target of this study is to develop a methodology analyzing the remaining efficiency of thermal straightening after block lifting. The development was based on the assumption of yield state at straightening region. Therefore the remaining efficiency was obtained by different stiffness slope while lifting & relieving. The efficiency formula was designed using inherent strain, and we made a table of zero-efficiency by cooling speed and class rule's steels. As a result, if the stress orthogonal to straightened line is calculated during lifting analysis by FEA, the efficiency can be obtained linearly to the values in the table. Finally, even optimized carling position can be designed by considering the regional data from series project and welding region on deck.

• 한국기계가공학회지
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• 제17권1호
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• pp.23-33
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• 2018

In the general manual feeder of an LED lighting assembly system, many workers are needed to supply parts to the main conveyor. The automatic feeder for modern automation lighting assembly systems consists of a completely automated feeding system and a magazine system that supplies the parts automatically. A standardized LED panel and diffusion cover is stacked in the cartridge of the magazine system. The structural safety of the automatic feeding system with regard to handling the load from the panels and covers stored in the cartridge should be guaranteed. LED convergency lighting modules are assembled using two LED panels and one diffusion cover in an automatic feeder. In this study, the structural safety and fatigue life of the automatic feeder and magazine were analyzed by considering the load generated in the automatically assembled LED convergency lighting system. In addition, the dynamic behavior of each auto-feeding system and magazine delivery system was visualized, and the working process was evaluated via dynamic simulation using a virtual engineering method. A tack time table for automatic feeding systems was derived by developing a virtual prototype.

• Journal of Nutrition and Health
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• 제40권1호
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• pp.89-96
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• 2007

This study was performed to weigh the average meal portion sizes served for preschoolers by kindergarten teacher. The subjects were 53 teachers from 8 kindergartens, which are random sampled by meal service number. Using the weighing method assessed the meal portion sizes of food items at lunch. The data was complied by performing $\chi^2-test$ using SPSS WIN 11.0. The result was as followed: 98.0% of teacher agreed with the meal service because of 'better food habit and table etiquette'(68.0%), 'health promotion with balanced diet'(22.0%), 'owing to extending school time'(6.0%) and 'demand of parents'(2.0%). Preschooler eat lunch at class (84.9%) and meal serving size was decided by teacher (79.2%). Teachers thought that they know very well about portion size 3.8%, 96.2% of teacher thought that they don't know much about portion size. Portion size were not significantly different by food tray types but there was much different (almost 100%) compared with minimum and maximum within dishes. Most average portion size was not met dietary reference intake except cooked rice, soups and fish cutlet. Working experience effected on portion size. More served, more working experienced of teacher. For example Bulgogi was served 26.8 g by teacher who has over 6 years working experience compared with 2-6 years (20.4 g) and less than 2 years (17.1 g) (p < 0.01). Spinach portion size was significantly different by teacher's working experience (p < 0.01). Portion size were not significantly different by preschooler's age. The reference of dietary for preschooler was different by age, but teachers served meal by their experience. According to the results of this study, it is necessary to educate meal portion size for kindergarten teacher who take charge in meal serving. To provide guidance to teacher about reasonable portion sizes for preschoolers, teacher need to take nutrition education about meal service and child nutrition in college. This study would be useful to those who plan meals for preschoolers and to researchers studying dietary intakes of preschooler.

• 한국생산제조학회지
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• 제23권5호
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• pp.435-442
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• 2014

This paper describes an improved design model that can be used to configure a non-contact pneumatic device to turn a large sheet at the in-line system. For rotational moving in the conveyor system, the conventional method is to turn the system itself. The improved non-contact pick-up system mainly uses 8 pairs of L-shaped latches and 12 swirl type heads. It is positioned above the upward air flow table. This system performs the non-contact gripping and side-edge contact support in the vertical and rotational directions to hold the self-weight of a large flat sheet. A non-contact air head can exert a sufficient gripping ability at 4N lower than the standard working pressure. The side latches support 60% of the lifting force required. Through structural and flow analysis, the working conditions were simultaneously considered in accordance with the deflection and flatness of the glass.

• 한국인구학
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• 제11권2호
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• pp.22-32
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• 1988

This study was conducted in order to compare the sequential changes of marital partnership and average marital life expectancy in Korea using Korean marriage life table for 1970, 1980, and 1985. The marriage life table was constructed by the Wolfbein-Wool method of constructing a working life table. Data used in this study was obtained from the Population Census Reports of Korea and the Korean Abridged life Tables. Some of the finding may be summarized as follows : 1. The marital partnership findings showed that males in the 40-44 age group in 1970 and in 1980 and those in the 45-49 bracket in 1985 have the highest rates of any other age interval, the percentages were 97.5% 97.3% and 96.9% respectively. The highest marital partnership rates for females were those aged 30-34 in 1970 and in 1980 and 35-39 in 1985:these were 94.6% 94.3% and 93.30% respectively. 2. The marital rate of the youngest age group has decreased due to the increasing amount of people marrying at older ages. On the other hand, the marital rates of the elderly has increased slightly due to the decreasing mortality rate. 3. The enterance rate of marriage at the 15-19 female age group ad the 20-24 male age group has decreased. 4. The secession rate of marriage has gradually decreased due to the decrease in the mortality rate. The main reason of secession for males is his own death. For females, the main reasons are divorce and the death of her spouse. 5. Korean average marital life expectancy has improved in general. In 1985 the average marital life expectancy for males was higher by 4-5 years than for females. The average difference of marital expectancy and life expectancy is about 1.4 - 1.5 years for males and about 11-14 years at the age groups below 60 years for females.

• 한국안전학회지
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• 제10권3호
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• pp.30-41
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• 1995

This paper proposed a simple method for measuring surface roughness of ground surface. Utilizing non-contact in-process measuring system using the diode laser. The measurement system is consisted of a laser unit with a diode laser and a cylindrical lens, a detecting unit with polygon mirror and CCD array sensor, and a signal processing unit with a computer and device. During operation, this measuring system can provide information on surface roughness in the measuring distance with a single sampling and simultaniously monitor the state of the grind wheel. The experimental results, showed that the Increase of the feed rate and the dressing speed an caused increase in the surface roughness and when the surface roughness is 4Rmax-10Rmax, the cutting speed is 1653m/min-1665m/min, the table speed is 0.2n1/min -0.9m/min, the dressing speed is 0.2mm/rev～0.4mm/rev, the stylus method and the in-process method can be obtained the same results. Thus, under limited working conditions, using the proposed system, the surface roughness of the ground surface during cylindrical grinding can be obtained through the in-process measurement method using the diode laser.

• 한국실내디자인학회논문집
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• 제38호
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• pp.250-257
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• 2003

The purpose of this study is to analyze the varying characteristic factors for residential kitchen remodeling according to contemporary life style. The subjects of this investigation are collected through questionnaire from adult residents who live in Seoul, Korea. The collected cases are analyzed by using Spss-win. By using the vaimax method on the basis of factor analysis, the satisfaction of the actual conditions is under the influence of finished materials & function, sanitary installation, layout, cooling & heating apparatus, day lighting, air conditioning, and safety. The preference of kitchen remodeling Is affected by finished materials, function, environmental equipment, and air conditioning. The Need of kitchen facility is caused by working table, refrigerator, gas range, dish apparatus, and addition function.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2004년도 추계학술대회 논문집
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• pp.54-59
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• 2004

A measure for good products manufactured by grinding process is the surface roughness that is affected by a lot of operating parameters such as types of abrasive, grain size, bond material, wheel speed, table speed, depth of cut, hardness of workpiece and stiffness of grinding machine. In this study, an application of the design of experiments was tried for evaluating the effect of operating parameters on the surface roughness. The workpiece was a high speed tool steel(SKH51) and the surface grinding was conducted. In order to obtain the best surface roughness within constraints of the working range, the optimal grinding conditions were selected. The usefulness of this method was evaluated by the statistical strategy.

• 한국직업건강간호학회지
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• 제11권2호
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• pp.132-149
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• 2002

Purpose: This study was conducted to provide the fadamental information to prepare better Occupational Health Program for SSI based on the evaluation of the experience of nurse who were working in the Government-funded subsidized occupational health program for SSI. Method: The focus group method was used. Data was collected using focus group interviews and analyzed in the framework of the Grounded theory method as mapped by Strauss and Corbin(1990). The subjects were 14 nurses. Result: We identified 60 concepts, 30sub-categories and 6 categories(Table 1). Categories were Various services, Difficulties in implement Services, Successful strategies, Program Evaluation, Alternative Plans and Adaptation to new field. Conclusion: Nurses evaluated the effect of this program that autonomous health management ability has not changed although the possibility for the small scale industries to start the health management arose by acknowledging the importance of the health management of the workplace. In spite of many difficulties in implement services, nurses provided various health services using successful strategies. They suggest that various programs such as a model set-up suitable for the quality of workplaces and a role model set-up of the occupational health nurse for SSI as well as various efforts for the activated this program were needed. Nurses had a hard time in unfamiliar field when they began this program and overcame this difficulties with various strategies.