• 한국측량학회지
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• 제24권2호
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• pp.183-191
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• 2006

최대 차수 10800의 초 고차 구 조화함수를 전개하여 중력을 모델링 하고, 이를 이용하여 상향 연속의 정확도를 검증하였다. 초 고차 구조화 함수에 의한 중력 모델링에 있어 수치계산적 난점인 르장드르 함수의 언더플로와 오버플로를 128 비트 연산에 의하여 성공적으로 수행하였으며, 이를 이용하여 지오이드상의 중력이상값을 공간 상도 $1'{\times}1'$ 으로 계산하였다. 생성된 중력이상값에 다양한 크기의 잡음을 첨가하고 자료의 간격을 달리하여 상향연속을 수행하였으며, 이로부터 도출된 중력 섭동 벡터와 중력 모델로부터 직접 계산된 섭동 벡터와의 비교를 통하여 실제적인 상향연속의 정확도를 할당하였다. 상향연속 방법의 비교에 있어, 직접방법이 포아송 방법에 비해 월등히 좋은 정확도를 보였고, 지상 중력자료의 잡음이 적을수록 또한 자료의 간격이 작을수록 상향연속에 의한 중력 섭동벡터의 정확도가 높게 나타남을 확인하였다. 특히 차세대 관성항법장치의 정밀 항법을 위한 중력의 필요조건인 5mGal의 정확도를 위해선, 지상 중력의 잡음 정도가 5mGal 이하, 자료의 간격이 2arcmin 이하이어야 함을 도출하였다.

• Journal of Advanced Marine Engineering and Technology
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• 제20권4호
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• pp.90-100
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• 1996

To maintain high spacial accuracy and rapid CPU time in interpolating data from grid to random position or inversely in PIV, proposed many technuques are compared and discussed mainly in terms of interpolating error and computing time. And artificial PIV atmosphere data is furnished by CFD result. First, for interpolation from grid to random position, multiquadric method gives the highest accuracy with the longest CPU time and Taylor series expansion methods give reasonable accuracy with less calculating load. Secondly, the sub-pixel resolution analysis in estimating the coordinates of the maximum correlation coefficients essential in the grey level correlation PIV reveal that 8-neighbours 2nd-order least square interpolation gives utmost accuracy in terms of the real flow conditions.

• Journal of Advanced Marine Engineering and Technology
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• 제20권4호
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• pp.412-412
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• 1996

To maintain high spacial accuracy and rapid CPU time in interpolating data from grid to random position or inversely in PIV, proposed many technuques are compared and discussed mainly in terms of interpolating error and computing time. And artificial PIV atmosphere data is furnished by CFD result. First, for interpolation from grid to random position, multiquadric method gives the highest accuracy with the longest CPU time and Taylor series expansion methods give reasonable accuracy with less calculating load. Secondly, the sub-pixel resolution analysis in estimating the coordinates of the maximum correlation coefficients essential in the grey level correlation PIV reveal that 8-neighbours 2nd-order least square interpolation gives utmost accuracy in terms of the real flow conditions.

• Journal of Gastric Cancer
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• 제10권2호
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• pp.49-54
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• 2010

Endoscopic resection is now accepted as curative treatment modalities for early gastric cancer without lymph node metastasis. However, based on large-scaled data about the risk of lymph node metastasis in early gastric cancer and as a result of the technical development of endoscopic devices, it was suggested that the criteria for endoscopic resection should be extended. According to the treatment guidelines for gastric cancer in Japan, the extended indications include the following: differentiated-type mucosal cancer without ulceration and greater than 2 cm in diameter, differentiated-type mucosal cancer with ulceration and up to 3 cm in diameter, undifferentiated-type mucosal cancer without ulceration and up to 2 cm in diameter, and, in the absence of lymphovascular invasion, a tumor not deeper than submucosal level 1 (less than $500\;{\mu}m$). In this review, we discuss the evidence of the application of expanded endoscopic indication based on analysis of biologic behavior and data of endoscopic resection.

• 유통과학연구
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• 제10권11호
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• pp.21-30
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• 2012

Purpose - This study aimed to analyze the strategy of late domestic entrants into the Chinese retail market, focusing on the case of Lotte-Mart, given that there are few studies on market entry strategies of domestic retail companies in China. Research Design, data, methodology - The methodology of this paper is a case study approach, focusing on literature reviews and a few interviews. We conducted a survey by disseminating questionnaires and conducting interviews focusing on the Chinese retail market, and analyzed Lotte-Mart's market entry strategy in China. Results - Lotte-Mart chose M&A as the mode of entry, pursuing quick market entry and rapid expansion. It chose small to medium size cities with relatively less competition. Subsequently, Lotte-Mart devoted significant effort towards localization, attempting to organize stores and assorting products to fit the Chinese consumers' preferences. It operated CSR programs to increase its brand awareness and to create a favorable brand image. Conclusions - Lotte-Mart now needs to devise alternative corporate strategies for business expansion and growth. An understanding of the Chinese retail market and the case study analysis of Lotte-Mart's market entry strategy offers significant insights for domestic retail companies looking to expand into China.

• Tribology and Lubricants
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• 제39권4호
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• pp.123-132
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• 2023

In this study, the expansion, stress, and operating clearance of bearing elements during operation are observed using the inner/outer ring temperature test data of a 3.0×10⁶ DN-class roller bearing. The operating clearance characteristics of inner-/outer-ring cooling (IORC) bearings are compared to those of inner-ring cooling (IRC) bearings. For IRC bearings, the thermal expansion of the outer ring is the most important factor in clearance variation. As a result, the operating clearance is less than the initial clearance of 61 ㎛, and the operating clearance decreases to 0.5 ㎛ at 25,500 rpm. Conversely, the temperature of the outer ring of IORC bearings is lower than that of IRC bearings, so the operating clearance is kept smaller. When the coolant flow rate to the outer ring is approximately 1.5 to 2.0 L/min, the temperature difference between the inner and outer rings is minimized and the operating clearance is maintained at a significantly lower level than IRC bearings. Small operating clearances are expected to be effective in reducing cage slip and skid damage in roller bearings. The results and analysis procedures of this study can be utilized to design of bearing clearance, lubricant flow rate, and assembled interference in the early design stage of aerospace roller bearings.

• 한국치위생학회지
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• 제12권2호
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• pp.409-417
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• 2012

Objectives : The purpose of this study is to figure out and establish the basic data that can help improve management of oral healthcare for the international marriage immigrant women. Methods : In this sense, we surveyed questions on 237 women out of 1,300 immigrant women, who have participated in the program by multi-cultural household supporting center, in a fashion of face-to-face investigation and on-the-spot direct cavity inspection simultaneously from May 1 to October 31, 2010. Collected data were electro-statistically computerized under SPSS 17.0 program and analyzed with frequency analysis, recurrence analysis and logistic regression analysis respectively. Results : The number of filled teeth got lower when they had lower number of dental visits. Women from the Philippines had the highest number of defect teeth, and the number of fixed prosthetic appliance became less when they had less number of dental visits. When they had no experience of oral health education, they had less fixed prosthetic appliances. There was higher percentage of periodontal disease when they did not have dental visit compared with the dental visit cases. Conclusions : Preparation of a policy for east Asian immigrant women for them to visit dentist comfortably and expansion of systematic oral health education are highly recommended.

• 한국물환경학회지
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• 제22권5호
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• pp.905-912
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• 2006

In this paper, simulation methods of the system dynamics model developed by Das et al. (1997) for activated-sludge wastewater treatment plants are illustrated in an attempt to determine the operating rules and the policies related to capacity expansion of an activated-sludge wastewater treatment plant. For existing conditions, the analyses were performed by varying activated-sludge return rate to observe changes in effluent water quality and treatment efficiency. The effluent water quality is also analyzed for various average daily inflow conditions and activated-sludge return rates. As a result, without expanding the aeration tank, maximum average daily inflow that can satisfy the effluent water quality standard of BOD $0.02kg/m^3$ was determined as $2,840m^3/hr$, subject to 100% of activated-sludge return rate while other factors remain constant. When the activated-sludge return rate is less than 100%, expansion of the aeration tank is necessary and minimum sizes of the aeration tank to satisfy the effluent water quality standard were determined for various activated-sludge return rates. In addition, the total operating and maintenance as well as unit treatment cost regression equations for activated-sludge wastewater treatment plants are suggested by using the cost data that are obtained from Water and Wastewater Division, Ministry of Environment. The regression analyses showed that the economies of scale phenomena exist in the operating and maintenance costs of activated-sludge wastewater treatment plants.

• 한국환경복원기술학회지
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• 제14권3호
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• pp.101-113
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• 2011

The purpose of this study are to develop a SDSS (Spatial Decision Support System) that can incorporate diverse opinions of stakeholders related the designation of protected areas (PA), and to employ the model for the readjustment of the boundary line of the Jirisan National Park of Korea. The SDSS would lead to more rational and less controversial decision-making during the expansion or removal of PA in Korea. Research methods are as follows. Firstly, to select evaluation criteria for SDSS for PA designation by using expert interview and literature survey. Secondly, to measure their preferences on the designation of additional PA or the removal of a part of PA based on the opinions of various stakeholders such as local residents, environmental groups, or public officials. Thirdly, to produce conservation priority maps based on a multi-criteria decision making technique. The SDSS would be used to rational decision making for the expansion of PA or the release of a certain part of PA by reflecting diverse preferences on biodiversity conservation and economic interest of residents. The visualization of conservation priority maps would also increase the efficiency of such decision making processes. The evaluation criteria for the expansion of PA for biodiversity conservation includes vegetation conservation value, wildlife conservation value, and the habitats of key species. The evaluation criteria for the removal of PA includes the proximity to roads and the boundary of PA, land use types, and conservation zoning of the PA. Preference weights are based on data collected from the Jirisan National Park. Both the conservation priority and removal priority maps are based on land parcels so that property rights of all parcels would be correctly represented.

• Archives of Plastic Surgery
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• 제49권6호
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• pp.729-739
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• 2022

Cranioplasties are common procedures in plastic surgery. The use of tissue expansion (TE) in staged cranioplasties is less common. We present two cases of cranioplasties with TE and systematically review literature describing the use of TE in staged cranioplasties and postoperative outcomes. A systematic review was performed by querying multiple databases. Eligible articles include published case series, retrospective reviews, and systematic reviews that described use of TE for staged bony cranioplasty. Data regarding study size, patient demographics, preoperative characteristics, staged procedure characteristics, and postoperative outcomes were collected. Of 755 identified publications, 26 met inclusion criteria. 85 patients underwent a staged cranioplasty with TE. Average defect size was 122 cm², and 30.9% of patients received a previous reconstruction. Average expansion period was 14.2 weeks. The most common soft tissue closures were performed with skin expansion only (75.3%), free/pedicled flap (20.1%), and skin graft (4.7%). The mean postoperative follow-up time was 23.9 months. Overall infection and local complication rates were 3.53 and 9.41%, respectively. The most common complications were cerebrospinal fluid leak (7.1%), hematoma (7.1%), implant exposure (3.5%), and infection (3.5%). Factors associated with higher complication rates include the following: use of alloplastic calvarial implants and defects of congenital etiology (p = 0.023 and 0.035, respectively). This is the first comprehensive review to describe current practices and outcomes in staged cranioplasty with TE. Adequate soft tissue coverage contributes to successful cranioplasties and TE can play a safe and effective role in selected cases.