• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.320-320
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• 2013

Film thickness monitoring with plasma impedance monitoring (PIM) is demonstrated for small area $SiO_2$ RF plasma etching processes in this work. The chamber conditions were monitored by the impedance signal variation from the I-V monitoring system. Moreover, modified principal component analysis (mPCA) was applied to estimate the $SiO_2$ film thickness. For verification, the PIM was compared with optical emission spectroscopy (OES) signals which are widely used in the semiconductor industry. The results indicated that film thickness can be estimated by 1st principal component (PC) and 2nd PC. Film thickness monitoring of small area $SiO_2$ etching was successfully demonstrated with RF plasma harmonic impedance monitoring and mPCA. We believe that this technique can be potentially applied to plasma etching processes as a sensitive process monitoring tool.

• Journal of the Korean Data and Information Science Society
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• v.27 no.6
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• pp.1621-1629
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• 2016

This paper studies Bayesian pooling for analysis of categorical data from small areas. Many surveys consist of categorical data collected on a contingency table in each area. Statistical inference for small areas requires considerable care because the subpopulation sample sizes are usually very small. Typically we use the hierarchical Bayesian model for pooling subpopulation data. However, the customary hierarchical Bayesian models may specify more exchangeability than warranted. We, therefore, investigate the effects of pooling in hierarchical Bayesian modeling for the contingency table from small areas. In specific, this paper focuses on the methods of direct or indirect pooling of categorical data collected on a contingency table in each area through Dirichlet priors. We compare the pooling effects of hierarchical Bayesian models by fitting the simulated data. The analysis is carried out using Markov chain Monte Carlo methods.

• Journal of Korean Society of Water and Wastewater
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• v.23 no.2
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• pp.181-187
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• 2009

In this study, a runoff hydrograph and runoff volume were calculated by using the kinetic wave theory for small urban watersheds based on the concept of low impact development(LID), and the effective imperviousness was estimated based on these calculations. The degree of sensitivity of the effective imperviousness of small watersheds to the impervious to pervious area ratio, infiltration capability, watershed slope, roughness coefficient and surface storage depth was then analyzed. From this analysis, the following conclusions were obtained: The effective imperviousness and paved area reduction factor decreased as the infiltration capability of pervious area increased. As the slope of watersheds becomes sharper, the effective imperviousness and the paved area reduction factor display an increasing trend. As the roughness coefficient of impervious areas increases, the effective imperviousness and the paved area reduction factor tend to increase. As the storage depth increases, the effective imperviousness and the paved area reduction factor show an upward trend, but the increase is minimal. Under the conditions of this study, it was found that the effective imperviousness is most sensitive to watershed slope, followed by infiltration capability and roughness coefficient, which affect the sensitivity of the effective imperviousness at a similar level, and the storage depth was found to have little influence on the effective imperviousness.

• Journal of the Korean Regional Science Association
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• v.40 no.2
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• pp.75-89
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• 2024

As the problem of lowering the efficiency of urban services in small and medium-sized cities in the non-metropolitan area intensifies, the necessity of developing a railway station area is being emphasized to form a compressed urban space through regional bases. Although major station areas in large cities are being developed in the form of complex, the analysis of the development location characteristics of the small and medium-sized city station areas is insufficient. The purpose of this study is to analyze the characteristics of development project conditions and potential demand in the high-speed rail station areas across the country, identify the differences in locational characteristics according to the type of city, such as 'metropolitan city', 'large city in non-metropolitan city', 'medium and small city in non-metropolitan city', and find out the appropriate development method. As a result of the analysis, it was analyzed that the 'metropolitan area metropolitan area' has high potential demand and poor business conditions. On the other hand, in the case of the non-metropolitan area, it was analyzed that the 'small and medium-sized city station area' has good business conditions and low potential demand characteristics, and the 'large city station area' has intermediate characteristics. This suggests the need for different development methods in the development of metropolitan and small and medium-sized city station areas. The analysis results of this study show that it is desirable to encourage private participation in large-scale metropolitan station areas, which require large-scale input, to maximize potential demand, and to encourage private participation through public-led projects based on favorable business conditions or development based on regional characteristics.

• Journal of the Korean Institute of Educational Facilities
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• v.21 no.5
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• pp.3-12
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• 2014

The purpose of this study is to propose a framework to analyse the educational effects and outcome of the boarding middle school established following the merger and abolition of small schools in rural area. According to the decrease in birth rate and reduction of population in rural area, primary schools have brought about many problems for decrease of number of student, and environment of education have became deteriorated. Accordingly, primary schools be required improvement, and it should be altered placement of schools because it change number of student, distance and time of attending school, and formation of school zone are changed by alternating of human and physical environment. Merger and abolition of primary school is inevitable for change of placement standard to primary school and qualitative improvement of environment of education in rural area. This study suggests 1)educational effects and outcome, 2)changes and benefits of student's living conditions, 3)social effects to local community, and 4)economical efficiency analysis as a new framework to evaluate the validity of establishing a school. It sets up a hypothesis that the students, parents and community satisfy the boarding school in rural area, a school record be improved and the abolition of schools have little effect on community. Finally, it emphasizes that in order to success the policy of the merger of small schools and the boarding middle school, it be attributed to the social-cultural environment based on local residents and community and required provision of a variety of utilization plans reflecting local specifics and guarantee of local residents' participation and selection.

• Journal of Environmental Science International
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• v.16 no.1
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• pp.95-102
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• 2007

The paper aims to highlight residents' preference of park close to industrial area in Seo-gu, Daegu City. Questionnaire survey was the main research method for the study from June to August last year. There were 2 survey questionnaires, one is for satisfaction degree regarding residents' general park use and the other is especially for vest-pocket use. For the research, 150 questionnaires were surveyed for each park users(total 300 questionnaires) and 270 questionnaires are used for the statistical analysis. The analysis showed that small vest pocket sized park was the proper model for close to industrial area. The majority residents preferred small park close to a residential area, also 77% of residents who use vest-pocket park replied that they live within 10 minute walking distance from there. In the case of Seo-gu, there were several small vest pocket sized parks which can satisfy the residents' preference. Therefore the plan which utilize them positively is necessary.

• Fisheries and Aquatic Sciences
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• v.27 no.1
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• pp.1-6
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• 2024

In this study, the swimming behavior of a small box jellyfish (Carybdea brevipedalia), which consists of inhaling external seawater and expelling it through its mouth to generate forward thrust, was characterized using particle image velocimetry (PIV). The flow rate and structure during the suction and discharge process were quantitatively analyzed. During swimming, there was a change in the ratio of the internal area during inhalation and expulsion. Specifically, there was a 1.10-fold difference between the maximum area after inhalation and the minimum area after discharge. The maximum distance traveled after discharge was inversely proportional to the size of the inner area, with a 2.48-fold difference in the minimum distance traveled after suction. Depending on the propulsion stage, the inner area decreased and then increased in proportion to the moving distance and speed. The moving distance of the small box jellyfish was measured for each period. The speed for each swimming stage increased and then decreased at intervals of 0.15 to 0.2 seconds, and the suction and discharge cycle period was measured at approximately 0.5 seconds. Collectively, our findings provide a methodological basis for studying the swimming behavior of small and highly active trailing jet jellyfish, as well as the biological mechanisms that determine this behavior.

• Korean Journal of Human Ecology
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• v.17 no.4
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• pp.661-677
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• 2008

The purpose of this study is to develop the playground environment model for child care center by analyzing user needs of playground environment. To systemize the playground environment design factors and guidelines, we reviewed the previous research, actual measurement and observation were used as the research methodology. And to recognize the needs of users, the survey and picture survey was conducted to the staffs and children. The scope of survey included child care centers in Seoul and Daejeon, ultimately selecting 12 places in Seoul and 13 places in Daejeon. In terms of the survey period, actual measurement was conducted from June of 2006 to February of 2007, survey and picture survey was conducted from August to September of 2006. For analysis, we used SPSS 10.0 to check the frequency and percentage, as well as to perform cluster analysis. The findings of research can be summarized as below: 1. In playground environment, we observed the area of play ground and ground cover, the independence of play area, play equipment, and the composition of play area. The result of observation showed that while playground area varied widely, ground cover, play equipment, and the composition of play area turned out to be identical, regardless of the playground's area. Therefore, in order to classify various playground environments, we categorized them into 5 types, using the number of children and the area of play ground as a category. Type A had large facilities and small playground area. Type B had small sized facilities and large playground area. Type C had medium sized facilities and small playground area. Type D had medium sized facilities but large playground area. Type E had large sized facilities and large playground area. 2. On the other hand, staffs wanted a tunnel, playhouse, comprehensive play equipment, and a maze to be installed as play facilities, and there were requests for adventure play area and carpenter play area. The picture survey to children showed that they wanted equipments that can provide more thrill, adventure and challenge to them than the ones they see now. Therefore, existing child care center play environments must change from the monotonous and identical environments to the ones that can provide diversities, challenges, and adventures. In the contexts of 5 playground types suggested by this research, type B and D, E where the area of playground were larger than the legally required, should include various play areas and install appropriate play equipments and facilities. Type A and C where the area were small, should provide multipurpose play area to attract the various play behaviors of children.

• Journal of Power System Engineering
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• v.12 no.2
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• pp.41-47
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• 2008

This article deals with the stress analysis of the friction drive, which transmits the power via the rolling resistance on the contract area between the two rotating bodies. On the contact area, friction drives are normally involved with shear stress due to the transmitted force, as well as normal stress. Thus the stress analysis including the shear stress is necessary for the design of the friction drive. Hertzian results can be used to estimate the normal stress distribution and elastic deflection of the contact area, although the shear stress distribution is not well defined. In order to investigate the shear stress distribution and its effects in a friction drive, we have performed the stress analysis of the spherical continuously variable transmission(CVT) using finite element method. The spherical CVT is one of friction drives, which is used in small power applications. The numerical results show that the normal stress distribution is not affected by the transmitted shear force, and the maximal shear stress is increased in small amount along with the shear force.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.55 no.11
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• pp.498-504
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• 2006

This paper describes the simple payback period analysis of small co-generation system based on the existing apartment and building data. First, We investigate apartment and building data more than $2000[m^2]$ using Ministry of Construction & Transportation's computer system. And then we calculate the latent amount of small co-generation system considering gas company and CHP. Second, we classify the latent amount of small co-generation system into office, hospital, hotel, department store, complex building and apartment. Finally, we perform the simple payback period analysis for small co-generation system. The results show the simple payback period of small co-generation system is less then 10 years.