• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.1033-1036
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• 2001

The object of this paper is to find out a coolant level, which is economic and similar to the conventional level, high level, in cutting temperature. For this, new coolant level, called a low level, was proposed, which is about 1/4 of conventional level. And the cutting temperature of each coolant level in turning was analyzed using statistical method. Firstly, it was analyzed that the temperature mean of each coolant level is not equal by ANOVA-test. Secondly by Tukey's HSD, one of multiple comparisons, it was analyzed that the temperature mean of low level is similar to that of high level and different from that of none level.

• Journal of the Korean Home Economics Association
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• v.28 no.1
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• pp.105-124
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• 1990

The purpose of this study is to investigate 1) the level of the city housewives' sense and behavior of wedding and ancestral service according to the background variables, 2) the relationship of the sense of wedding and ancestral service and behavior, and 3) what the most influential factors are. For the purpose of this study, 700 questionnaire were distributed to the housewives who live in Seoul and collected during the February 1989. And the measuring instruments are composed of 9 questions, 11 questions of the sense of wedding service, 12 questions of the sense of ancestral service, 11 questions of the behavior of wedding service, and 12 questions of the behavior of ancestral service. To obtain the sense and behavior of wedding and ancestral service scale, item analysis through Pearon's correlation and factor analysis, frequency distribution, percentile, mean, standard deviation, t-test, F-test, Pearson's γ, Paired-t-test, Duncan's Multiple Range Test, and Stepwise multiple Regression were used for data analysis. The major fidnigs are as follows: 1. The general tendency of the city housewives' sense of wedding service was modern. That of the city housewives' sense of ancestral service was the mid level of the traditional and the modern. According to background variable (ie: age, educational level, the number of children, the duration of marriage, religion, the existence of job, the existence of married son and daughter), the city housewives' sense of wedding service is different significantly. Accoring to background variable(ie: age, educational level, the average home income a month, the number of children, the duration of marriage, religion, the existence of married son and daughter), the city housewives' sense of ancestral service is different significantly. 2. The general tendency of the city housewives' behavior of wedding service was modern. That of the city housewives' behavior of ancestral service was somewhat modern. According to background variable(ie: age, educational level, the number of children, the duration of marriage, the existence of married son and daughter, the form of family), the city housewives' behavior of wedding service is different significantly. According to background variable(ie" age, educational level, the number of children, the duration of marriage, religion, the existence of job, the existence of married son and daughter), the city housewives' behavior of ancestral service is different significantly. 3. There were positive correlation between the city housewive' sense and behavior of wedding and ancestral service(P<.001). And the housewives' sense of wedding service was modernized than that of ancestral service, the housewives' behavior of ancestral service was modernized than that of wedding service. 4. The city housewives' sense of wedding service was the duration of marriage(β=-.226), influential factor. And influential factors on that of ancestral service were educational level(β=.250), the existence of married son and daughter(β=-.123), number of children(β=-.101). The influential factors on the city housewives' behavior of wedding service were age(β=-.193), the form of family(β=.097). And that of ancestral service were educational level(β=165), the number of children(β=-.157).

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.26 no.3
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• pp.324-333
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• 2016

Objectives: We aimed to compare the sampling performance of different flow-based impactor samplers for collecting fungal spores and bacteria and to explore the association of the level of bioaerosols with activity patterns of occupants in daycare center settings. Methods: For comparison of sampling performance, two different flow-based samplers (greater than 100 L/min or not) were selected; a low flow-based sampler (one-stage Andersen sampler) and two high flow-based samplers (DUO SAS SUPER 360 sampler, BUCK bio-culture sampler). We collected airborne mold and bacteria in 30 daycare centers with various levels of contaminated air. Three repeat samplings per each sampler were performed. Mold and bacteria were grown for 96 hours at $25{\pm}1^{\circ}C$ and 48 hours at $35{\pm}1^{\circ}C$, respectively. The Andersen and SAS samplers were used for investigating the association between the level of bioaerosols and the activity patterns of occupants in daycares. Particular matters 10($PM_{10}$), temperature, and relative humidity were monitored as well. Samplings were carried out with one-hour interval from 9 to 5 O'clock. For statistical comparisons, Kruskal-Wallis test, Wilcoxon's signed rank test, and multiple regression analysis were carried out. Results: The airborne level of molds by the low flow-based sampler were significantly higher than that of high flow-based samplers (indoor, P=0.037; outdoor, P=0.041). However, no statistical difference was observed in the airborne level of bacteria by each sampler. Also the level of bioaerosols varied by the time, particularly with different activity patterns in daycare centers. The higher level of mold and bacteria were observed in play time in indoor. Similarly, the concentrations of $PM_{10}$ were significantly associated with the level of bioaerosols (P<0.05). Conclusions: Our findings indicate that the flow rate of sampler, rather than total air volume, could be able to affect the results of sampling. Also, the level of airborne mold and bacteria vary behavior patterns of occupants in indoor of daycare settings. Therefore, different samplers with other flow rate may be selected for mold or bacteria sampling, and activity patterns should be considered for bioaerosol sampling as well.

• Korean Journal of Heritage: History & Science
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• v.34
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• pp.138-171
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• 2001

This paper, based on the filed survey conducted from August 14 to 21, 2000, examines the architectural characteristics of traditional dwellings of Sujeonchon(수전촌, 水田村) village. Sujeonchon village is located on the northen slope of Changbaishan Mt., Andohyun(안도현, 安圖縣) of jilin Province(吉林省), a province in the northeastern region of China. The village was established between late 1940's and early 1950's by the Korean-Chinese. Later on, some of the Korean-Chinese residents moved out of the village and presently, the residents are composed of both the Korean-Chinese and the Chinese consisting about fifty-fifty. Since the cultural background and the living custom are different from each other ethnic group, that is, the Korean-Chinese and the Chinese, their dwellings reveal some differences between them. Through the study, the architectural characteristics and distinctions of the Korean-Chinese and Chinese dwellings are found and summarized as follows: 1.The way of building layout is different between them: the Chinese mainly follows the north-south direction of building layout, while the Korean-Chinese considers the surrounding environmental condition. 2.The floor level of kitchen is different between them: that of the Chinese house is same as the outdoor earth level, while that of the Korean-Chinese is lower than the outdoor level. 3.The way of providing the kitchen space is different between them: the kitchen of the Chinese house is consist of one separate room, while that of the Korean-Chinese is open to the living area. 4.The way of heating system is different between them: the Chinese house has kang only at the sleeping area, while the Korean-Chinese install whole under-floor heating of gudeul in the living area. 5.The attitude to the way of building is different between them: the Chinese are easily adapt to the new building materials and construction method, while the Korean-Chinese are showing strong attachment to the traditional way of building. 6.The houses of the Chinese and the Korean-Chinese have their own traditional ornaments and talismans on and in the building.

• Journal of the Korean Home Economics Association
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• v.38 no.3
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• pp.25-42
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• 2000

To examine toddlers’adjustment in child care centers according to the quality of child care environment, the followings were asked; 1. Are toddlers’adjustment in child care centers different by toddlers’individual characterisitcs, caregiyer’s individual characteristics, and/or care center variabless\ulcorner 2. Are the quality of child care center different by caregiver’s individual characteristics and child care center variables\ulcorner 3. Are toddlers’adjustment in child care centers different according to the quality of child care center\ulcorner Forty caregivers and 108 toddlers in 40 child care centers in Inchon were randomly selected. After 2 hours of observation in each child care center, the quality of child care environment were rated using Infant/Toddler Environment Rating Scate(ITERS) by 2 observers and toddlers’adjustment in child care centers were rated by caregivers using the Preschool Adjustment Questionnaire(PAQ). Toddlers’adjustment in centers were different by toddlers’gender, caregiver’s age, caregiver’s educational level, group size, and the adult/child ratio. The quality of child care environment of child care centers was different by caregiver’s age, caregiver’s career level, the length of working time, group size, and the adult/child ratio. Finally, toddler’s adjustment in child care centers were significantly different by the quality of child care environment of child care centers.

• Journal of the Korea Society of Computer and Information
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• v.4 no.4
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• pp.199-208
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• 1999

The purpose of this study is to find a cause of economic performance differences among industries. For this purpose, several hypothesis are established and tested (1) Whether the firm's capability and performance are different among industries\ulcorner (2) Whether the firm's management resources affects the performance are different among industries\ulcorner (3) Whether the firm's performances are different between high performance group and low performance group in same industry\ulcorner The results of this study are (1) the level of firm's capability and performance are different and (2) the management resources which affect the performance are different according the industry. And (3) the management resources are different according to the firm's performance level in same industry.

• The Korean Journal of Physiology and Pharmacology
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• v.5 no.6
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• pp.467-477
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• 2001

We examined astrocyte regional heterogeneity in their morphological changes in response to various stimuli. Astrocytes were cultured from six different neonatal rat brain regions including cerebral cortex, hippocampus, cerebellum, mid brain, brain stem and hypothalamus. Astrocyte stellation was induced by serum deprivation and the maximum stellation in different regional astrocytes was achieved after 2 h. After 24 h, in all astrocyte cultures, the level of stellation returned to their original level. Cerebellar or hypothalamic astrocytes were the most or the least sensitive, respectively, to serum deprivation. The order of maximum sensitivity to serum deprivation among different regional astrocytes was: cerebellum＞mid $brain{\ge}hippocampus,\;brain\;stem{\ge}cerebral$ cortex＞hypothalamus. Isoproterenol-induced astrocyte stellation was also examined in different regional astrocytes, and similar order of maximum sensitivity as in serum deprivation was observed. Next a possible developmental effect on astrocyte morphological changes was examined in cerebral cortex and cerebellum astrocytes cultured from postnatal day 1 (P1), P4 and P7 rat brains. A much higher sensitivity of cerebellum astrocytes to serum deprivation as well as isoproterenol treatment was consistently observed in P1, P4 and P7-derived astrocytes compared to cerebral cortex astrocytes. The present study demonstrates different regional astrocytes maintain different levels of morphological plasticity in vitro.

• Korea Information Processing Society Review
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• v.11 no.6
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• pp.56-75
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• 2004

In this article we address some system characteristics and challenging issues in developing Context-aware Middleware for Ubiquitous Computing. The functionalities of a Context-aware Middleware includes gathering context data from hardware/software sensors, reasoning and inferring high-level context data, and disseminating/delivering appropriate context data to interested applications/services. The Middleware should facilitate the query, aggregation, and discovery for the contexts, as well as facilities to specify their privacy policy. Following a formal context model using ontology would enable syntactic and semantic interoperability, and knowledge sharing between different domains. Moddleware should also provide different kinds of context classification mechanical as pluggable modules, including rules written in different types of logic (first order logic, description logic, temporal/spatial logic, fuzzy logic, etc.) as well as machine-learning mechanical (supervised and unsupervised classifiers). Different mechanisms have different power, expressiveness and decidability properties, and system developers can choose the appropriate mechanism that best meets the reasoning requirements of each context. And finally, to promote the context-trigger actions in application level, it is important to provide a uniform and platform-independent interface for applications to express their need for different context data without knowing how that data is acquired. The action could involve adapting to the new environment, notifying the user, communicating with another device to exchange information, or performing any other task.

• Journal of Environmental Science International
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• v.13 no.6
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• pp.497-503
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• 2004

In this research, we have performed a T-test to see how the relationship between dependent variable or visual point level and independent variable or visual quantity is in order to clear up the correlation between pattern of visual point and visual quantity by the constituents of a view from a different visual point level and the results are as follows: 1) In case of the character of Mt. Uam landscape of the city, Uamsan is set as a fixed point and about a direction of view(D), the north is a datum point from which the range of direction is distributed within 1800 westwardly and the visual range(R) is also within 2000m. An elevation is an average of 7.40 and the average story of the buildings is 3.85. Here the height of a story is about 4m so the average of the visual point difference is estimated at 15.4m. 2) The type of visual point is divided into the intersection group and the front of the highly used public buildings group. Double intersection types account for about 78.80%(52 spots) which forms a majority part of LCP. 3) The analysis of the difference of visual point level divided by eye level and that of the top of the buildings has been proved that there's a sharp difference resulted from t-test at 1 % significant level. The significant difference of elevation from height difference(l5.93m), however, has not been shown. 4) From the result of T-test about visual quantity by the elements of a view from a different visual point level, the visual quantity of mountain(VQM), sky(VQS), ground(VQG) is significant at about 1% each and that of building(VQB) is at about 5%. The difference in visual quantity of a mountain by the visual point level is at about 4% which can meet a marginal level of LCP necessary for evaluation of mountainscape.

• The Journal of Advanced Prosthodontics
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• v.12 no.5
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• pp.316-321
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• 2020

PURPOSE. The stress distribution and microgap formation on an implant abutment structure was evaluated to determine the relationship between the direction of the load and the stress value. MATERIALS AND METHODS. Two types of three-dimensional models for the mandibular first molar were designed: bone-level implant and tissue-level implant. Each group consisted of an implant, surrounding bone, abutment, screw, and crown. Static finite element analysis was simulated through 200 N of occlusal load and preload at five different load directions: 0, 15, 30, 45, and 60°. The von Mises stress of the abutment and implant was evaluated. Microgap formation on the implant-abutment interface was also analyzed. RESULTS. The stress values in the implant were as follows: 525, 322, 561, 778, and 1150 MPa in a bone level implant, and 254, 182, 259, 364, and 436 MPa in a tissue level implant at a load direction of 0, 15, 30, 45, and 60°, respectively. For microgap formation between the implant and abutment interface, three to seven-micron gaps were observed in the bone level implant under a load at 45 and 60°. In contrast, a three-micron gap was observed in the tissue level implant under a load at only 60°. CONCLUSION. The mean stress of bone-level implant showed 2.2 times higher than that of tissue-level implant. When considering the loading point of occlusal surface and the direction of load, higher stress was noted when the vector was from the center of rotation in the implant prostheses.