• Restorative Dentistry and Endodontics
• /
• v.23 no.2
• /
• pp.618-629
• /
• 1998

CAD/CAM-fabricated ceramic restorations nowadays are used as alternatives of amlagam and posterior composite resin restorations, especially in the cases of inlay restorations. But the reported results on marginal and internal fit of CAD/CAM-fabricated ceramic inlay have showed considerable difference. In this study, to evaluate the marginal and internal fit of CEREC2-fabricated ceramic inlay restoration and to compare with the fit of gold inlay and amalgam restoration, standardized Class II MO cavities were prepared in forty extracted caries-free human premolars. The teeth with prepared cavities were divided into 4 groups of ten teeth each. In group 1, CEREC2-fabricated ceramic inlays were treated with Scotchbond Multi-Purpose Plus(SMP plus) and cemented with Scotchbond Resin Cement. In group 2, casted gold inlays were cemented in the same method as in group 1. In group 3, casted gold inlays were cemented with zinc-phosphate cement. And in group 4, the prepared cavities were restored with amalgam. Restored teeth were thermocycled, stored in 1% methylene blue for 24 hours, and sectioned faciolingually and mesiodistally using EXAKT. Sectioned surfaces were observed with stereomicroscope and the gaps were measured at 9 points of mesiodistally sectioned surface and 7 points of faciolingually sectioned surface. The measured data were treated by Kruskal-Wallis one way ANOVA and Student-Newman-Keuls test. 1. The differences among measured gaps at each points were statistically significant for 4 experimental groups (P<0.05). 2. There were statistically significant differences in the measured gaps at each points between group 1 and group 2, group 1 and group 3, group 1 and group 4, group 2 and group 4, and group 3 and group 4 (P<0.05). 3. There were not statistically significant differences in the measured gaps at each points between group 2 and group 3 (P>0.05). 4. In the cases of inlay restorations(group 1, group 2, group 3), the gaps at internal line angle(distopulpal, axiogingival, faciopulpal, linguopulpal line angle) had a tendency to increase. In the cases of amalgam restorations(group 4), the gaps at occlusal margin, gingival margin and axiogingival line angle were greater than those at the other parts of cavities. 5. In CEREC2-fabricated ceramic inlays which were treated with Scotchbond Multi-Purpose Plus and cemented with Scotchbond Resin Cement, the mean gaps were $111{\mu}m$ at cavity margins, $168{\mu}m$ at vertical walls of cavities, $225{\mu}m$ at internal line angles and $123{\mu}m$ at cavity floors.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.14 no.2
• /
• pp.595-609
• /
• 2020

In this study, we propose a decentralized mathematical model for predictive control of a system of multi-autonomous unmanned aerial vehicles (UAVs), also known as drones. Being decentralized and autonomous implies that all members make their own decisions and fly depending on the dynamic information received from other unmanned aircraft in the area. We consider a variety of realistic characteristics, including time delay and communication locality. For this flocking flight, we do not possess control for central data processing or control over each UAV, as each UAV runs its collision avoidance algorithm by itself. The main contribution of this work is a mathematical model for stable group flight even in adverse weather conditions (e.g., heavy wind, rain, etc.) by adding Gaussian noise. Two of our proposed variance control algorithms are presented in this work. One is based on a simple biological imitation from statistical physical modeling, which mimics animal group behavior; the other is an algorithm for cooperatively tracking an object, which aligns the velocities of neighboring agents corresponding to each other. We demonstrate the stability of the control algorithm and its applicability in autonomous multi-drone systems using numerical simulations.

• Journal of the Korean BIBLIA Society for library and Information Science
• /
• v.27 no.3
• /
• pp.201-233
• /
• 2016

The purpose of this study is to improve awareness of cultural diversity and respect different culture, value and lifestyle by providing children from multi cultural family and children from non multi cultural family who are from third to sixth year in elementary school with education on cultural diversity. This study developed cultural diversity education program in public library and applied it to analyze a difference in awareness of cultural diversity education program, a difference in awareness of cultural diversity education program between experimental group and comparative group, library service, use of library service and influence of expansion of service. As a results, it was found that cultural diversity education program helped children understand, accept, consider and respect cultural diversity better.

• Journal of Korea Society of Digital Industry and Information Management
• /
• v.11 no.3
• /
• pp.63-68
• /
• 2015

We consider a cell edge environment. In cell edge, a user interfered by signal which is generated by a base stations not including the user. In cell edge environment, that is, there are inter cell interference (ICI) as well as multi user interference (MUI). Coordinated multi-point transmission (CoMP) is a technique which mitigates ICI between base stations. In CoMP, therefore, base stations can coordinate with each other by sharing user state information (CSI) in order to mitigate ICI. To improve sum rate performance in CoMP, each base station should generate optimal user group and transmit data to users selected in the optimal user group. In this paper, we propose a user selection algorithm in CoMP. The proposed method use signal to interference plus noise ratio (SINR) as criterion of selecting users. Because base station can't measure accurate SINR of users, in this paper, we estimate SINR equation considering ICI as well as MUI. Also, we propose a user selection algorithm based on the estimated SINR. Through MATAL simulation, we verify that the proposed method improves the system sum rate by an average of 1.5 ~ 3 bps/Hz compared to the conventional method.

• Structural Engineering and Mechanics
• /
• v.47 no.2
• /
• pp.265-286
• /
• 2013

A study on economic performances of consecutive multi-span suspension bridges is carried out. In this part of the study, material amount and structural cost estimation formulas of the bridges is derived based on the structural ultimate carrying capacity. The bridge cost includes the part of superstructure and the part of substructure. Three types of bridge foundations, bored piles, concrete caissons and floating foundations, are considered in substructure. These formulas are to be used for the parametric study of the bridge cost in order to define its more economical layout under different conditions in the part two of the study.

• Journal of Korean Society for Quality Management
• /
• v.42 no.4
• /
• pp.617-632
• /
• 2014

Purpose: This study aims to explore the relationship between the focal firm's interdepartmental cooperation and new product development (NPD) performance with focus on the moderating effect of environmental uncertainty. The basic hypothesized model is that there are positively associated relationships. Methods: The proposed research model was tested using structural equation modeling with 601 responses from multi-functional and multiple respondents in Korean manufacturing firms. Multi-group SEM analyses were conducted to explore the degree to which the hypothesized model was equivalent for different levels of environmental uncertainty. Results: Interdepartmental cooperation between R&D and production is positively associated with NPD performance under both higher and lower environmental uncertainties, while one between R&D and marketing is positively associated under only higher environmental uncertainty. Conclusion: This paper determined that NPD performance is positively correlated with R&D-production cooperation in a focal firm, and the relationship between R&D-marketing cooperation and NPD performance is positively moderated by level of environmental uncertainty. Consequently, this study suggests that it is always important for firms to put much effort on R&D-production cooperation for a better NPD performance, while R&D-marketing cooperation should be enhanced especially under higher environmental uncertainty than lower.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.14 no.5
• /
• pp.660-665
• /
• 2004

In this study, a new architecture and comprehensive design methodology of genetically optimized Multi-layer Fuzzy Neural Networks (gMFNN) are introduced and a series of numeric experiments are carried out. The gMFNN architecture results from a synergistic usage of the hybrid system generated by combining Fuzzy Neural Networks (FNN) with Polynomial Neural Networks (PNN). FNN contributes to the formation of the premise part of the overall network structure of the gMFNN. The consequence part of the gMFNN is designed using PNN. The optimization of the FNN is realized with the aid of a standard back-propagation learning algorithm and genetic optimization. The development of the PNN dwells on the extended Group Method of Data Handling (GMDH) method and Genetic Algorithms (GAs). To evaluate the performance of the gMFNN, the models are experimented with the use of a numerical example.

• Korean Journal of Veterinary Pathology
• /
• v.1 no.1
• /
• pp.13-25
• /
• 1997

The anticarcinogenic effects of dimethyl disulfide(DMDS, methyl disulfide)and diallyl disulfide(DADA, allyl disulfide) were studied in a 28 weeks rat multi-organ carcinogenesis model. neoplastic and preneoplastic lesions were observed in the liver kidney thyroid gland esophagus duodenum colon, rectum and adrenal gland. Tesults showed that neoplastic lesions in the kidney liver and thyroid gland were inhibited by DADS but those in the liver and colon were enhanced by DMDS when compared to positive control group. incidence of neoplastic lesions in the other organs were not changed by DMDS or DADS exposure. While GST-p positive foci in the liver were increased by DMDS, DADS had no effect. There was no significant histopathological lesion in DMDS or DADS treated group without pretreatment with carcinogens.

• International Journal of Fuzzy Logic and Intelligent Systems
• /
• v.7 no.1
• /
• pp.17-21
• /
• 2007

Multi-Agent Robotic System (MARS) is a system that independent autonomous robots in the restricted environments infer their status from pre-assigned conditions and operate their jobs through the cooperation with each other. In the MARS, a robot contains sensor part to percept the situation around themselves, communication part to exchange information, and actuator part to do given work. Especially, in order to cooperate with other robots, communicating with other robots is one of the essential elements. Because Bluetooth has many advantages such as low power consumption, small size module package, and various standard protocols, Bluetooth is rated as one of the efficient communicating technologies which can apply to small-sized robot system. In this paper, we will develop Bluetooth communicating system for autonomous robots. For the purpose, the communication system must have several features-separated module, flexible interface. We will discuss how to construct and what kind of procedure to develop the communicating system.

• Journal of Family Resource Management and Policy Review
• /
• v.13 no.2
• /
• pp.153-167
• /
• 2009

This research analyzes factors of family life adjustment in mixed-culture families through a focus group and individual interviews with nine mixed-culture couples eighteen people who live in city C. First, the reason that women of other cultures wants to marry Korean men is because they find it a good opportunity, as they expect that Korean husbands will take responsibility of their family. On the other hand, Korean men also expect that they would have some similarities to each other. Also, in southeastern Asian men have more freedom than women to choose an international marriage in Southeastern Asia. Second, mixed-culture couples in everyday life are affected by communication problems, cultural differences, natural environment, financial situation, male -dominant attitude, self-adjustment pressure, house-work role and financial support from their own country. Third, wives from other cultures ask for social support to adjust in Korea and make a healthy family. These women can be important, as they have their own role in the family even though they may be far from their mother in law's strong expectation in how well she can adopt Korean culture.