• Journal of the Korean Statistical Society
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• 제32권3호
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• pp.245-259
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• 2003

The 2-way balanced one-level rotation design has been discussed (Park et al., 2001), where the 2-way balancing is done on interview time in monthly sample and rotation group. We extend it to 3-way balanced multi-level design to obtain more information of the same sample unit for one or more previous months. The 3-way balancing is accomplished not only on interview time in monthly sample and rotation group but also on recall time as well. The 3-way balancing eliminates or reduces any bias arising from unbalanced interview time, rotation group and recall time, and all rotation groups are equally represented in the monthly sample. We present the rule and rotation algorithm which guarantee the 3-way balancing. In particular, we specify the necessary and sufficient condition for the 3-way balanced multi-level rotation design.

• Journal of the Korean Physical Society
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• 제80권
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• pp.30-36
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• 2022

Holographic model of massive scalar field with its self-interaction λϕⁿ in AdS space is able to give a logarithmic scale dependence to marginal multi-trace deformation couplings on its dual conformal field theory, where λ is the self-interaction coupling of the scalar field, ϕ, and n is an integral number. In arXiv:1501.06664, the authors realize this feature by looking at bulk scalar solutions near AdS boundary imposing a specific boundary condition between the coefficients of non-normalizable and normalizable modes of the scalar field excitations. We study the same holographic model to see scale dependence of marginal deformations on the dual conformal field theory by employing completely different method: holographic Wilsonian renormalization group. We solve Hamilton-Jacobi equation derived from the holographic model of massive scalar with λϕⁿ interaction and obtain the solution of marginal multi-trace deformations up to the leading order in λ. It turns out that the solution of marginal multi-trace deformation also presents logarithmic behavior in energy scale near UV region.

• 대한소아치과학회지
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• 제25권1호
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• pp.103-115
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• 1998

Adhesion of composite resin to tooth structure has been of tremendous signgicance in clinical dentistry. Due to the lack of adhesion between composite restorative resins and enamel and dentin, microleakage occurs at the tooth/restoration interface. This may lead to discoloration, secondary caries, marginal breakdown, postoperative sensitivity, and even pulpal pathology. According to extensive use of composite resin, every effort on improving bonding strength and reducing microleakage between a tooth and composite resin has been continued. This study was conducted to determine the difference in microleakage in enamel and dentin treated with air-abrasion, acid etching and combination when restored with composite resin. Class V cavities were prepared on 30 premolars. The specimens were divided into following groups. group 1:air-abrasion+Scotchbond Multi-purpose group 4 :air-abrasion+All-Bond 2 group 2:acid etching+Scotchbond Multi-purpose group 5 :acid etching+All-Bond 2 group 3:combination+Scotchbond Multi-purpose group 6 :combination+All-Bond 2 #combination:air-abrasion + acid etching The specimens were filled with Z-100 after application of Scotchbond Multi-purpose and All-Bond 2. Thermocycling was conducted by alternately dipping the specimens in $5^{\circ}C$ and $55^{\circ}C$ water for 30 seconds 500 times. 1% methylene blue was applied and the specimens were left for 24 hours at $37^{\circ}C$. After washing out the dye, the tooth was sectioned buccolingually along the axis. The sectioned surface was observed with stereoscope for dye penetration. The author has measured the microleakage in teeth prepared with air-abrasion, acid ethching and combination to study the difference in microleakage following different methods of tooth surface treatment and has come to following results. 1. In comparing microleakage between groups, group 1 and 4 showed statistically significant difference from group 2, 3, 5 and 6(p<0.05). There was no significant difference among group 2, 3, 5, 6(p>0.05) nor between group 1 and 4(p>0.05). 2. In comparing microleakage among tooth surface treatment methods, Air-abrasion group showed significantly more microleakage than acid etching group and combination(airabrasion + acid etching) group(p<0.05). Combination(acid etching+air-abrasion)group tended to show lesser microleakage than acid etching group, but this was not statistically significant(p>0.05). 3. In comparing microleakage between bonding agents, there was no statistically significant difference between Scotch bond Multi-purpose and All-Bond 2(p>0.05).

• 근관절건강학회지
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• 제27권1호
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• pp.31-40
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• 2020

Purpose: This study was done to examine the effect of a multi-component cessation program on bone union by comparing the union time between the experimental group and the control group. Methods: A non-equivalent control group posttest design was used. The subjects were 33 patients in the experimental group and 33 patients in the control group, 66 patients in total. The subjects of the experimental group were provided with a face-to-face multi-component smoking cessation program. After the discharge, telephone consultation was provided once a week for 10 weeks. Results: Bone union time was 51.6±10.9 days in the experimental group and 60.9±13.83 days in the control group (p=.003). Among 33 subjects who participated in the smoking cessation program, the average union period of the participants who succeeded in quitting smoking was 44.56 days, the participants who reduced smoking were 50.67 days, and failed to quit smoking group was 60.11 days (p=.006). Conclusion: This study indicated the importance of smoking cessation in patients with fracture and the decrease in the union time by providing smoking cessation education. If the multi-component smoking cessation program is used as a nursing intervention in clinical practice, it will be effective for bone union by increasing the smoking cessation rate of patients with fracture.

• 센서학회지
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• 제27권3호
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• pp.186-191
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• 2018

Smart textile industries have been precipitously developed and extended to electronic textiles and wearable devices in recent years. In particular, owing to an increasingly aging society, the elderly healthcare field has been highlighted in the smart device industries, and pressure sensors can be utilized in various elderly healthcare products such as flooring, mattress, and vital-sign measuring devices. Furthermore, elderly healthcare products need to be more lightweight and flexible. To fulfill those needs, textile-based pressure sensors is considered to be an attractive solution. In this research, to apply a textile to the second layer using a pressure sensing device, a novel type of conductive textile was fabricated using vapor phase polymerization of poly(3,4-ethylenedioxythiophene) (PEDOT). Vapor phase polymerization is suitable for preparing the conductive textile because the reaction can be controlled simply under various conditions and does not need high-temperature processing. The morphology of the obtained PEDOT-conductive textile was observed through the Field Emission Scanning Electron Microscope (FESEM). Moreover, the resistance was measured using an ohmmeter and was confirmed to be adjustable to various resistance ranges depending on the concentration of the oxidant solution and polymerization conditions. A 3-layer 81-point multi-pressure sensor was fabricated using the PEDOT-conductive textile prepared herein. A 3D-viewer program was developed to evaluate the sensitivity and multi-pressure recognition of the textile-based multi-pressure sensor. Finally, we confirmed the possibility that PEDOT-conductive textiles could be utilized by pressure sensors.

• 방송공학회논문지
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• 제11권4호
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• pp.458-470
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• 2006

본 논문에서는 MPEG-4 Systems 기반 복수시점 영상 서비스를 위한 저작 기술에 대해 제안한다. MPE-4는 이전의 MPEG-l/2 등의 비디오 정보 압축 규격과 달리, 사용자와 콘텐츠 간의 객체 기반 대화형(interactivity) 기능에 대한 다양한 방법을 포함하고 있다. 따라서 MPEG-4 Systems 규격은 현재까지 개발된 표준들 중에서 복수시점 영상 서비스가 제공하려고 하는 목적에 가장 잘 부합하는 기능을 제공하고 있다. 본 논문에서는 MPEG-4 Systems 표준 기술을 기반으로 제공될 수 있는 복수시점 영상 서비스에 대해 기술하였고, 해당 서비스를 제공하기 위한 MPEG가 장면 기술(scene description) 프로파일을 제안하였다. 또한 제안된 프로파일에 기반을 둔 대화형 복수시점 영상콘텐츠 저작시스템을 설계하고 구현하였으며, 실험결과를 통해 그 가능성을 보여 주었다.

• Nuclear Engineering and Technology
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• 제55권6호
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• pp.1974-1987
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• 2023

The load-following operation of small modular reactors (SMRs) requires accurate prediction of transient behaviors that can occur in the balance of plants (BOP) and the nuclear steam supply system (NSSS). However, 1-D thermal-hydraulics analysis codes developed for safety and performance analysis have conventionally excluded the BOP from the simulation by assuming ideal boundary conditions for the main steam and feed water (MS/FW) systems, i.e., an open loop. In this study, we introduced a lumped model of BOP fluid system and coupled it with NSSS without any ideal boundary conditions, i.e., in a closed loop. Various methods for coupling boundary conditions at MS/FW were tested to validate their combination in terms of minimizing numerical instability, which mainly arises from the coupled boundaries. The method exhibiting the best performance was selected and applied to a transient simulation of an integrated NSSS and BOP system of a SMART. For a transient event with core power change of 100-20-100%, the simulation exhibited numerical stability throughout the system without any significant perturbation of thermal-hydraulic parameters. Thus, the introduced boundary-condition coupling method and BOP fluid system model can expectedly be employed for the transient simulation and performance analysis of SMRs requiring daily load-following operations.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 동계학술발표대회 논문집
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• pp.21-26
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• 2008

Recently, small and medium-sized buildings have employed a multi-heat pump. The major benefits of the multi-heat pump over a conventional system are that it is easier system to maintain along with a diversification of facility use, and high comfortability. The performance of multi-heat pump systems can be enhanced by using geothermal energy instead of air source energy. This paper describes the multi-heat pumps applied in an ground source heat pump system for an actual building. The performance of a ground source multi-heat pump installed in the field was investigated in cooling mode. The maximum COP of the systems with single U-tube and double tube ground loop heat exchangers were 6.6 and 6.0, respectively. It is suggested that the new algorithms to control the flow rate of secondary fluid for ground loop heat exchanger have to be developed in order to enhance the performance of the system.

• 품질경영학회지
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• 제33권3호
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• pp.59-70
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• 2005

The purpose of this research is to identify the impact of trust on user acceptance of mobile banking and to identify if causalities among these factors are different between Internet and mobile banking. To test this model, this research applies the technology acceptance model(TAM) that incorporates trust. Additionally, this research use structural equation modeling to test the model and examine cross-group differences using a multi-group comparison method. The empirical results indicate that all path is significant expect the path from trust to intention to use. The results of a multi-group comparison test indicated that the path from trust to attitude, from trust to intention to use, from perceived usefulness to attitude and from perceived to intention to use are different between Internet and mobile banking.

• Nuclear Engineering and Technology
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• 제34권3호
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• pp.250-258
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• 2002

This Paper is to apply the well-established coarse mesh finite difference(CMFD) method to the method of characteristics(MOC) transport calculation as an acceleration scheme. The CMFD problem is first formulated at the pin-cell level with the multi-group structure To solve the cell- based multi-group CMFD problem efficiently, a two-group CMFD formulation is also derived from the multi-group CMFD formulation. The performance of the CMFD acceleration is examined for three test problems with different sizes including a realistic quarter core PWR problem. The CMFD formulation provides a significant reduction in the number of ray tracings and thus only about 9 ray tracing iterations are enough for the realistic problem. In computing time, the CMFD accelerated case is about two or three times faster than the coarse-mesh rebalancing(CMR) accelerated case.