• Journal of Korean Tunnelling and Underground Space Association
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• v.19 no.3
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• pp.503-515
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• 2017

Underground structures that have recently become larger are required to be stable not only during normal times but also during earthquakes. Especially, it is very important to maintain the stability of the subsea tunnels during the earthquake. The objective of this paper is to verify the effectiveness of the flexible segment, which is one of the breakthrough facilities to maintain the stability of the subsea tunnel during the earthquake using the shaking table test. Another goal of this paper is to propose the optimum position of the flexible segment through 3D dynamic numerical analysis based on the verified results from shaking table tests. The 1g shaking table test considering the similarity ratio (1:100) to the cross section of the selected artificial subsea tunnel was carried out considering the Geongju and Artificial seismic waves, longitudinal and lateral wave, and with/without flexible segments eight times or more. As a result of the shaking table test, it was confirmed that the flexible segment is effective in improving the seismic performance of the undersea tunnel in all the experimental results. In addition, 3D dynamic numerical analysis was performed to select the optimum position of the flexible segment which is effective for improving seismic performance. As a result, it was confirmed that the seismic acceleration is attenuated when the flexible segment is installed adjacent to the branch section in subsea tunnel.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.2
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• pp.129-138
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• 2012

In this study, three types of large scale multi-tasking machine tools together with core technologies involved have been developed and introduced; a multi-tasking machine tool for large scale marine engine crankshafts, a multi-tasking vertical lathe for windmill parts, and a large scale 5-axis machine tool of gantry type. Several special purpose devices has been necessarily developed for the purpose of handling and machining big and heavy workpieces accurately, such as PTD (Pin Turning Device) with revolving ring spindle for machining eccentric crankshaft pins, hydrostatic rotary table and steady rest for supporting and resting heavy workpieces, and 2-axis automatic swiveling head for high-quality free surface machining. Core technologies have been also developed and adopted on their detail design stage; 1) structural design optimization with FEM structural analysis, 2) theoretical hydrostatic analysis for the PTD and rotary table bearings, 3) box-in-box type cross-rail and octagonal ram design to secure machine rigidity and accuracy, 4) constant spindle rpm control against gravitational torque due to unbalanced workpiece.

• Tribology and Lubricants
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• v.37 no.6
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• pp.224-231
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• 2021

Recently, the waterproofing performance of high-voltage connectors in automotive vehicles has attracted increased interest. In this study, an optimal cross-sectional shape was derived to obtain uniform contact pressure and strain by considering stress relaxation problems caused by initial tension when mounting a seal. A high strain of 52.1 was distributed in the round region, owing to excessive initial tension. The finite element method (FEM) analysis indicated that the strain corresponding to the optimal initial tensile was 11. We adopted six design factors to optimize the seal cross-section and three factors as the main design factors. An orthogonal arrangement table was prepared using Minitab. FEM analyses of 16 study models were conducted to determine the optimized model. The contact pressure of the optimization model is the most evenly distributed while satisfying the waterproof performance of 0.47 MPa. Compared to the initial model, the difference in strain decreases from 35.5% to 19.6%. Finally, the derived cross-sectional shape can reduce the strain of the round region by 33.8% and the differences in the contact pressure at the upper and lower surfaces by 42% and 76%, respectively.

• The Journal of Engineering Geology
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• v.25 no.3
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• pp.349-356
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• 2015

Although geophysical methods are useful and generally provide valuable information about the subsurface, it is important to recognize their limitations. A common limitation is the lack of sufficient contrast in physical properties between different layers. Thus, multiple methods are commonly used to best constrain the physical properties of different layers and interpret each section individually. Ground penetrating radar (GPR) and shallow seismic reflection (SSR) methods, used for shallow and very shallow subsurface imaging, respond to dielectric and velocity contrasts between layers, respectively. In this study, we merged GPR and SSR data from a test site within the Cheongui granitic mass, where the water table is ~3 m deep all year. We interpreted the data in combination with field observations and existing data from drill cores and well logs. GPR and SSR reflections from the tops of the sand layer, water table, and weathered and soft rocks are successfully mapped in a single section, and they correlate well with electrical resistivity data and SPS (suspension PS) well-logging profiles. In addition, subsurface interfaces in the integrated section correlate well with S-wave velocity structures from multi-channel analysis shear wave (MASW) data, a method that was recently developed to enhance lateral resolution on the basis of CMP (common midpoint) cross-correlation (CMPCC) analysis.

• International Journal of Human Ecology
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• v.6 no.1
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• pp.61-74
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• 2005

This paper utilized a Korean time-use survey and household expenditure survey in designing an input-output table to develop satellite accounts of household production in Korea in 1999. Additionally, the household production in Korea was compared with that in the United States, Australia, Finland, and Canada. Results of this study may be summarized as follows. First, household production in Korea represented $43\%$ of Gross Domestic Product (GDP,) compared to $63\%$ of GDP in the United States, $68\%$ in Australia, $58\%$ in Finland, and $54\%$ in Canada. Second, labor emerged as the largest input for household production in Korea, while materials and services - both intermediate goods - emerged as the second input. On the other hand, the proportion of housing among the four inputs of household production in Korea was greater than for either the United States or the other countries studied. This implies that the cost of intermediate goods and housing in Korea is more expensive than in other countries.

• Journal of Applied Tourism Food and Beverage Management and Research
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• v.12 no.2
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• pp.43-58
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• 2001

This study focuses on analyzing the present conditions of homestay in Donghae, which helps to increase the fishing and agrarian villages' income and offer a low-priced lodging facility to tourists. Furthmore it tries to find the related problems and to suggest the solutions. For this purpose, homestsy businesses in Donghae city was surveyed by the questionnaire. Frequency analysis and Cross table analysis of the collected 97 questionnaries were conducted by the SPSS, and the related problems were found as follows. After homestay business turned to the liberal business, professional homestay businessmen appeared and conflicts between farmer and professional businessman came out. And there's a limitation on providing subsidiary facilities and services for the local businesses because of their financial difficulty and on-off season. Therefore to develop “fishing and agrarian villages' homestay businesses” well-defined standards of homestay is required. Then to provide subsidiary facility, services and special programs activation of homestay association is necessary. Finally, to attract tourists, local government's tourist attraction policy is needed.

• Proceedings of the ESK Conference
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• 1993.10a
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• pp.205-219
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• 1993

The purpose of this study was to determine maximal width of bodice and skirt pattern of 50 college girls for more scientific patternmaking development in clothing construction. The body measurements data of this study was calculated by SAS, means analysis, regression analysis and T-test were used. The results are as follows. 1. The results of analyzing the whole 85 items of the entire body measurements of model are in table 2. 2. It was suggested the whole average cross section of measurement parts by rohrer index as the result of gathering the each section. 3. Representative items were suggested as fundamental parts in determining the maximal width of bodice and skirt basic pattern by rohrer index. 4. The entire abbreviated calculation formula of bodice and xkirt pattern was suggested.

• Journal of Korean Society of Transportation
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• v.28 no.4
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• pp.19-30
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• 2010

It has become important to have some proper guidelines of how to provide public transport information services in response to the rapid IT developments and the wide spread of public information services. The current study takes a contextual approach to the analysis of public transportation information use under a dynamic decision situation, complementing the conventional cross-sectional approaches. Using the CHAID of decision tree induction based on decision table formalism applied to the survey data of activity travel and information use, the study found that the information type and medium choices are strongly affected by the decision contexts in addition to the individuals' socio-demographic characteristics. The results suggest an important implication to the market segmentation of information services for public transportation.

• Journal of the Korean Geosynthetics Society
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• v.10 no.3
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• pp.53-62
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• 2011

This paper presents the characteristics behavior of dike structure and foundation ground through the shaking table model test. The vibration loadings of design earthquake acceleration of 0.154g was applied to this laboratory model test regarding on dike structure and foundation ground under the structure. The model was formulated with 1/100 design of representative cross section for evaluating the effectiveness of vibration. Based on the test results, we can analysis the behavior of lateral displacement and settlement characteristics of structure under the earthquake loading. The pore water pressure was also monitored in the upper, middle and lower layers of ground. Finally, the actual displacements and pore water pressure of the structure can be predicted by using the results of the laboratory shaking table test.

• Korean Institute of Interior Design Journal
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• v.20 no.3
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• pp.182-189
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• 2011

This research suggests a way of hygienic space planing of the customer space in the university student restaurant of E University in Seoul. For this study. the behavior observation in the restaurant was conducted in order to analyze the sequence of customer behavior related space planing applying HACCP (Hazard Analysis And Critical Control Point). Also the survey was conducted to analyze opinions of customers about hygiene of the space. The results of the analyses of the observation and the survey were similar in terms of hygiene. In conclusion, for hygienic space planing of the customer space in restaurant, the space circulation should be planned according to the hygienic sequence of customer behavior. The spaces in restaurant should be divided into two areas: the clean area and the contaminated area to prevent cross-contamination. The clean area, such as spaces preparing dishes and food including water and table hall where customers eat, should be separated from the contaminated area such as the spaces where waste is handled and where dirty dishes are kept. In order to prevent cross-contamination, hygiene facility to remove contamination should be located before going to the clean area. More specifically, the hygiene facility should be located between a cash counter and a space preparing dishes so that customers can wash their hands before they touch dishes. Space arrangement with feed-back process to check the possible points of cross-contamination and correct space arrangement until the possibility of cross-contamination is removed in the restaurant.