• Journal of dental hygiene science
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• v.13 no.1
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• pp.91-96
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• 2013

The purpose of this study was to examine the possibility of the existence of high-risk groups of dental caries and influential factors for the high-risk groups, as there was a possibility that certain people might especially be at risk of suffering from dental caries when decayed, missing, and filled teeth index were analyzed, which were the typical indicators of dental caries. The data of the 4th National Health & Nutrition Survey for 2007, 2008 and 2009 were analyzed. Significant caries index (SiC index) were calculated, which were one of the representative devices to indicate high-risk groups of dental caries, and the SiC index and related factors were analyzed by using $x^2$ (chi-square) test. Besides, logistic regression analysis was utilized to find out influential factors, and a statistical package STATA 11.0 was employed. As a result of analyzing what factors would be linked to high-risk groups of dental caries, it's found that women were more likely to belong to high-risk groups than men (p<0.01). How the related factors affected the high-risk groups was analyzed, and it's found that those who didn't find themselves to be in good oral health were more likely to be classified into a high-risk group, and that those who brushed their teeth three times a more a day on a regular basis were more likely to belong to a high-risk group than the others who didn't (p<0.01). Thus, SiC index were calculated in this study to confirm the existence of dental caries high-risk groups, and what factors impacted on the high-risk groups was ascertained. It's required to implement efficient national policies to step up the promotion of national oral health based on the findings of the study.

• Journal of Broadcast Engineering
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• v.15 no.2
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• pp.265-279
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• 2010

A color image requires at least three color channels to obtain the full color image. However the image sensor obtains only the intensity of the brightness, that is, three image sensors are required for every pixel to capture the full color image. Since the image sensor is quiet expensive, most of digital still cameras adopt single image sensor array with color filter array (CFA) to reduce the size and the cost. Since the image obtained using single sensor array has only one color component per pixel, we need to reconstruct the missing two color components to obtain the full color image. We call this process as color filter interpolation or demosaicking. In this paper, demosaicking algorithm composed of two large step is proposed. Proposed algorithm is combined with several different algorithms such as Edge-directed demosaicking, Second-order gradients as correction terms, Smooth hue transition Interpolation, etc. The simulation results show that the proposed algorithm performs much better than the state-of-the-art demosaicking algorithms in terms of both subjective and objective qualities.

• Land and Housing Review
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• v.2 no.1
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• pp.9-17
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• 2011

A urban regeneration project of Korea has been promoted highly attaching to physical reforms, but without fulfilling the basic goal of reactivating city functions through concerning overall areas. Moreover, the general rule and its system of urban regeneration project which would provide roles of public and civilians as well as facilitate cooperative urban regeneration, are currently missing. Thus, social stratum continuously requests a framework act for urban regeneration project called Control Tower, to be a guide to the evidently right path to step up. The research analyzes the current status and problems of urban regeneration projects in Korea to examine the necessity of Control Tower, and to bring up the way to move on for its efficiency presented below: First, the law should be declarative; possess general, prospective influences on laws and systems related to urban regeneration. Second, the nonbinding guideline on a urban regeneration project should be suggested to reflect the conditions by the regions. Last, propulsions should be framed such as administrative principles of strengthening publicity and connection of urban regeneration projects, a committee and fund to promote the former, and a research for problem solution.

• Journal of the Korea Convergence Society
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• v.12 no.1
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• pp.99-104
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• 2021

In this paper, we propose health risk management using feature extraction and cluster analysis considering time flow. The proposed method proceeds in three steps. The first is the pre-processing and feature extraction step. It collects user's lifelog using a wearable device, removes incomplete data, errors, noise, and contradictory data, and processes missing values. Then, for feature extraction, important variables are selected through principal component analysis, and data similar to the relationship between the data are classified through correlation coefficient and covariance. In order to analyze the features extracted from the lifelog, dynamic clustering is performed through the K-means algorithm in consideration of the passage of time. The new data is clustered through the similarity distance measurement method based on the increment of the sum of squared errors. Next is to extract information about the cluster by considering the passage of time. Therefore, using the health decision-making system through feature clusters, risks able to managed through factors such as physical characteristics, lifestyle habits, disease status, health care event occurrence risk, and predictability. The performance evaluation compares the proposed method using Precision, Recall, and F-measure with the fuzzy and kernel-based clustering. As a result of the evaluation, the proposed method is excellently evaluated. Therefore, through the proposed method, it is possible to accurately predict and appropriately manage the user's potential health risk by using the similarity with the patient.

• Journal of Industrial Convergence
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• v.20 no.3
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• pp.89-97
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• 2022

The purpose of this study is to understand the effect of volunteer activities and self-development activities of elementary school students on subjective happiness and to verify the mediating effect of leadership life skills based on this. The subjects were surveyed in 2018 by the Korea Youth Policy Institute, and out of 2,739 elementary school students, unresponsive and missing values were removed and the final 1,978 were selected. As a result of the analysis, it was found that leadership life skills were completely mediated in the relationship between volunteer work and subjective happiness of elementary school students. For the analysis method, SPSS 25.0 program was used to achieve the purpose of this study. And to verify the mediating effect, a 3-step mediating effect analysis was performed by Baron & Keeny(1986). It was confirmed that leadership life skills were completely mediated in the relationship between self-development activities and subjective happiness. Based on these research results, in order to increase the subjective happiness of elementary school students, measures were discussed to develop practical skills that can improve communication and organizational management skills, which are leadership life skills.

• The Journal of Korean Academy of Prosthodontics
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• v.60 no.1
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• pp.63-70
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• 2022

Teeth wear with loss of posterior support often leads to symptoms such as irregular occlusal plane and excessive wear of anterior teeth. In such environment, establishing proper posterior support and harmonious anterior guidance and occlusal plane is recommended. In this case, the patient had excessively worn dentition with loss of posterior support, while denying surgical treatment due to her(his) history of osteoporosis, ibandronate injection, and risk of medication-related osteonecrosis of the jaw (MRONJ). To recover the vertical space needed for prosthetic restoration, full mouth rehabilitation with vertical dimension increase of remaining teeth was decided. Missing teeth in the posterior area were restored with mandibular removable partial denture. The treatment plan was determined through careful diagnosis, and every step of procedures including tooth preparation, provisional phase with the increased vertical dimension, and definitive prosthetic phase were carried out accordingly. Once the treatment was completed, the patient was satisfied functionally and esthetically. Periodic examination of oral hygiene, occlusal stability was conducted.

• Journal of Intelligence and Information Systems
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• v.23 no.4
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• pp.111-126
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• 2017

Recommender systems based on association rule mining significantly contribute to seller's sales by reducing consumers' time to search for products that they want. Recommendations based on the frequency of transactions such as orders can effectively screen out the products that are statistically marketable among multiple products. A product with a high possibility of sales, however, can be omitted from the recommendation if it records insufficient number of transactions at the beginning of the sale. Products missing from the associated recommendations may lose the chance of exposure to consumers, which leads to a decline in the number of transactions. In turn, diminished transactions may create a vicious circle of lost opportunity to be recommended. Thus, initial sales are likely to remain stagnant for a certain period of time. Products that are susceptible to fashion or seasonality, such as clothing, may be greatly affected. This study was aimed at expanding association rules to include into the list of recommendations those products whose initial trading frequency of transactions is low despite the possibility of high sales. The particular purpose is to predict the strength of the direct connection of two unconnected items through the properties of the paths located between them. An association between two items revealed in transactions can be interpreted as the interaction between them, which can be expressed as a link in a social network whose nodes are items. The first step calculates the centralities of the nodes in the middle of the paths that indirectly connect the two nodes without direct connection. The next step identifies the number of the paths and the shortest among them. These extracts are used as independent variables in the regression analysis to predict future connection strength between the nodes. The strength of the connection between the two nodes of the model, which is defined by the number of nodes between the two nodes, is measured after a certain period of time. The regression analysis results confirm that the number of paths between the two products, the distance of the shortest path, and the number of neighboring items connected to the products are significantly related to their potential strength. This study used actual order transaction data collected for three months from February to April in 2016 from an online commerce company. To reduce the complexity of analytics as the scale of the network grows, the analysis was performed only on miscellaneous goods. Two consecutively purchased items were chosen from each customer's transactions to obtain a pair of antecedent and consequent, which secures a link needed for constituting a social network. The direction of the link was determined in the order in which the goods were purchased. Except for the last ten days of the data collection period, the social network of associated items was built for the extraction of independent variables. The model predicts the number of links to be connected in the next ten days from the explanatory variables. Of the 5,711 previously unconnected links, 611 were newly connected for the last ten days. Through experiments, the proposed model demonstrated excellent predictions. Of the 571 links that the proposed model predicts, 269 were confirmed to have been connected. This is 4.4 times more than the average of 61, which can be found without any prediction model. This study is expected to be useful regarding industries whose new products launch quickly with short life cycles, since their exposure time is critical. Also, it can be used to detect diseases that are rarely found in the early stages of medical treatment because of the low incidence of outbreaks. Since the complexity of the social networking analysis is sensitive to the number of nodes and links that make up the network, this study was conducted in a particular category of miscellaneous goods. Future research should consider that this condition may limit the opportunity to detect unexpected associations between products belonging to different categories of classification.

• Restorative Dentistry and Endodontics
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• v.32 no.2
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• pp.111-120
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• 2007

The purpose of this study is to evaluate the effects of surface treatment and composition of reinforcement material on fracture strength of fiber reinforced composite inlay bridges. The materials used for this study were I-beam, U-beam TESCERA ATL system and ONE STEP(Bisco, IL, USA). Two kinds of surface treatments were used; the silane and the sandblast. The specimens were divided into 11 groups through the composition of reinforcing materials and the surface treatments. On the dentiform, supposing the missing of Maxillary second pre-molar and indirect composite inlay bridge cavities on adjacent first pre-molar disto-occlusal cavity, first molar mesio-occlusal cavity was prepared with conventional high-speed inlay bur. The reinforcing materials were placed on the proximal box space and build up the composite inlay bridge consequently. After the curing, specimen was set on the testing die with ZPC. Flexural force was applied with universal testing machine (EZ-tester; Shimadzu, Japan). at a cross-head speed of 1 mm/min until initial crack occurred. The data was analyzed using one-way ANOVA/Scheffes post-hoc test at 95% significance level. Groups using I-beam showed the highest fracture strengths (p<0.05) and there were no significant differences between each surface treatment (p>0.05) Most of the specimens in groups that used reinforcing material showed delamination. 1. The use of I-beam represented highest fracture strengths (p<0.05) 2. In groups only using silane as a surface treatment showed highest fracture strength, but there were no significant differences between other surface treatments (p>0.05). 3. The reinforcing materials affect the fracture strength and pattern of composites inlay bridge. 4 The holes at the U-beam did not increase the fracture strength of composites inlay bridge.

• The Journal of Korean Academy of Prosthodontics
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• v.59 no.4
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• pp.487-496
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• 2021

Full mouth rehabilitation is re-organizing the occlusion of the remaining teeth and missing teeth considering the functions, esthetics, and neuromuscular harmony. With the loss of multiple teeth, the patient's occlusal plane gradually collapses and the vertical dimension can be reduced. Since reduced vertical dimension can be a potential etiology of the temporomandibular joint and masticatory muscles, prosthetic restoration with increased vertical dimension is required. This case report is about a 68 years old patient with vertical dimension loss due to worn dentition and multiple loss of teeth. In this case, the loss of vertical dimension is assessed carefully using the digital dentistry technology. Using CAD software in digital analysis step, the occlusal plane was established and evaluated using several criteria. Orienting the position of the bone and teeth using CBCT image, patient's condition was visualized in 3 dimension and treatment planning was possible virtually. The information that matches the patient's condylar position with the articulator, which is the virtual face bow, is reproduced on the actual articulator, and evaluated again. After the evaluation, provisional prosthesis was fabricated and it was confirmed that the patient adapts without any abnormality. This was implemented as a final prosthesis. As a result, the patient obtained satisfying results, utilizing the benefits of digital dentistry technology and traditional methods.

• The Korean Journal of Air & Space Law and Policy
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• v.27 no.2
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• pp.211-241
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• 2012

The Draft International Code of Conduct for Outer Space Activities officially proposed by the European Union on the occasion of the 55th Session of the United Nations Peaceful Uses of the Outer Space last June 2012 in Vienna, Austria is to fill the lacunae of the relevant norms to be applied to the human activities in the outer space and thus has the merit our attention. The missing elements of the norms span from the prohibition of an arms race, safety and security of the space objects including the measures to reduce the space debris to the exchange of information of space activities among space-faring nations. The EU's initiatives, when implemented, cover or will eventually prepare for the forum to deal with such issues of interests of the international community. The EU's initiatives begun at the end of 2008 included the unofficial contacts with major space powers including in particular the USA of which position is believed to have been reflected in the Draft with the aim to have it adopted in 2013. Although the Code is made up of soft law rather than hard law for the subscribing countries, the USA seems to be afraid of the eventuality whereby its strategic advantages in the outer space will be affected by the prohibiting norms, possibly to be pursued by the Code from its current non-binding character, of placing weapons in the outer space. It is with this trepidation that the USA has been opposing to the adoption of the United Nations Assembly Resolutions on the prevention of an arms race in the outer space (PAROS) and in the same context to the setting-up of a working group on the arms race in the outer space in the frame of the Conference on Disarmament. China and Russia who together put forward a draft Treaty on Prevention of the Placement of Weapons in Outer Space and of the Threat or Use of Force against Outer Space Objects (PPWT) in 2008 would not feel comfortable either because the EU initiatives will steal the lime light. Consequently their reactions are understandably passive towards the Draft Code while the reaction of the USA to the PPWT was a clear cut "No". With the above background, the future of the EU Code is uncertain. Nevertheless, the purpose of the Code to reduce the space debris, to allow exchange of the information on the space activities, and to protect the space objects through safety and security, all to maximize the principle of the peaceful use and exploration of the outer space is the laudable efforts on the part of EU. When the detailed negotiations will be held, some problems including the cost to be incurred by setting up an office for the clerical works could be discussed for both efficient and economic mechanism. For example, the new clerical works envisaged in the Draft Code could be discharged by the current UN OOSA (Office for Outer Space Affairs) with minimal additional resources. The EU's initiatives are another meaningful contribution following one due to it in adopting the Kyoto Protocol of 1997 to the UNFCCC (UN Framework Convention on the Climate Change) and deserve the praise from the thoughtful international community.