• Journal of Technologic Dentistry
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• v.37 no.4
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• pp.205-212
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• 2015

Purpose: The objective of this study was to compare the surface roughness according to polishing process in conventional laboratory techniques used for polishing three different acrylic denture base resins. Materials and methods: Specimen preparation and surface polishing procedures were conducted to manufacturer's recommendation with three heat-polymerized denture base resins. Surface roughness and gloss were measured by a contact type tester and a LED gloss checker using thickness 2 mm and diameter 10 mm. There were five specimens for each acrylic resin material and polishing procedures. Mean average surface roughness (Ra) values of each specimen group were analyzed using a one-way ANOVA analysis of variance and Scheffe's post hoc test. Surfaces after surface roughness and gloss testing according to each polishing process were evaluated under a stereoscopic microscope. Results: The highest mean average surface roughness was measured($Ra=2.43{\pm}0.47$) for surfaces finished with a denture tungsten carbide bur in Triplex. The lowest surface roughness values ($Ra=0.11{\pm}0.07$) were determined in Vertex polished with a lathe. In addition, all materials revealed that surface roughness determined highly in HP1 and HP2 than other procedures. All correlation between surface roughness and gloss showed highly with three heat-polymerized resins. Specially, topmost correlation revealed than other material in Triplex. Significant differences in mean average surface roughness were found between polishing process used high speed lathe and low speed hand-piece. Conclusion: Laboratory polishing used to high speed was found to produce the smoothest surface of heat-polymerized denture base acrylic resin. Therefore, we recommended that high polishing process need to get smooth surface.

• Journal of Internet Computing and Services
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• v.16 no.6
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• pp.23-30
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• 2015

As BigData is issued, many applications that operate based on the results of data analysis have been developed, typically applications are products recommend service of e-commerce application service system, search service on the search engine service and friend list recommend system of social network service. In this paper, we suggests a decision frequent pattern tree that is combined the origin frequent pattern tree that is mining similar pattern to appear in the data set of the existing data mining techniques and decision tree based on the theory of computer science. The decision frequent pattern tree algorithm improves about problem of frequent pattern tree that have to make some a lot's pattern so it is to hard to analyze about data. We also proposes to model for a Mapredue framework that is a programming model to help to operate in distributed environment.

• Journal of Food Hygiene and Safety
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• v.1 no.1
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• pp.107-113
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• 1986

It is estimated that the loss of Korean agricultural and fishery products during the storage period is usually more than 20%, and it is difficult to increase agricultural products by a 10% annual rate directly. Therefore, development of food preservation techniques has now become a most important atternative for the indirect increase of such products and for its senitary distribution. Changes eating habits and improved living conditions have accelerated the demand for convenience food production and for this reason it is essential that raw materials at stable, resonable prices and hygienic quality be available the year round. At the end of 1980, the Korean government conceded th economical feasibility of the storage of foods by irradiation and a procedure for preserving food by irradiation on a batch scale was successfully developed by KAERI in 1982. Based on the research results accomplished by the KAERI and on the recommendation on wholesomeness of irradiated food by Joint Committee of FAO/IAEA/WHO in 1980, the approval of wholesomeness of irradiated food was declared by presidential decree in June 1985 and the procedure of permission for individual items is in progress. Korean private firms (Ryung Young Co.) which was technically assisted by KAERI for five years have taken mush interest in the establishment of such facilities in Korea, therefore Ryung Young Co. had proposed for the construction of 500 Kci Co-60 irradiator to the Ministry of Science and Technology in July 1984. The permission of construction has approved by government in May 1985. The commercial irradiator will be constructed as one of the most modernized facilities until May 1987 and that facilities will contribute the propagation of commercial storage of foods and its hygienic quality.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.10
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• pp.1433-1443
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• 1993

DCT(Discrete Cosine Transform) / IDCT(Inverse DCT) is widely used in various image compression and decompression systems as well as in DSP(Digital Signal Processing) applications. Since DCT/ IDCT is one of the most complicated part of the compression system, the performance of the system can be greatly enchanced by improving the speed of DCT/IDCT operation. In this thesis, we designed a DCT/IDCT core processor using module generator technique. By utilizing the partial sum and DA(Distributed Arithmetic) techniques, the DCT/ IDCT core processor is designed within small area. It is also designed to perform the IDCT(Inverse DCT) operation with little additional circuitry. The pipeline structure of the core processor enables the high performance, and the high accuracy of the DCT/IDCT operation is obtained by having fewer rounding stages. The proposed design is independent of design rules, and the number of the input bits and the accuracy of the internal calculation coa be easily adjusted due to the module generator technique. The accuracy of the processor satisfies the specifications in CCITT recommendation H, 261.

• The Journal of Society for e-Business Studies
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• v.12 no.3
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• pp.269-282
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• 2007

We propose a personalized concept-based retrieval technique that uses domain ontology. Proposed system consist or representative concept extraction, user profile construction, and concept-based retrieval stages. First, we extract representative concept with using technique form contents and create the domain ontology. We compose user profile analysis that uses domain ontology for personalized concept-based retrieval. To verify the efficiency of the proposed technique, we perform experiment for Internet site in the engineering area. The results of experiment show that the proposed technique using the domain ontology and user profiles is more efficient than the existing techniques. Hence, the proposed concept-based retrieval technique can be expected to contribute to the development of an efficient personalized recommendation system or e-Commerce system.

• Journal of Information Technology Services
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• v.16 no.3
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• pp.167-183
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• 2017

The rapid growth of information technology and mobile service platforms, i.e., internet, google, and facebook, etc. has led the abundance of data. Due to this environment, the world is now facing a revolution in the process that data is searched, collected, stored, and shared. Abundance of data gives us several opportunities to knowledge discovery and data mining techniques. In recent years, data mining methods as a solution to discovery and extraction of available knowledge in database has been more popular in e-commerce service fields such as, in particular, movie recommendation. However, most of the classification approaches for predicting the movie popularity have used only several types of information of the movie such as actor, director, rating score, language and countries etc. In this study, we propose a classification-based support vector machine (SVM) model for predicting the movie popularity based on movie's genre data and social network data. Social network analysis (SNA) is used for improving the classification accuracy. This study builds the movies' network (one mode network) based on initial data which is a two mode network as user-to-movie network. For the proposed method we computed degree centrality, betweenness centrality, closeness centrality, and eigenvector centrality as centrality measures in movie's network. Those four centrality values and movies' genre data were used to classify the movie popularity in this study. The logistic regression, neural network, $na{\ddot{i}}ve$ Bayes classifier, and decision tree as benchmarking models for movie popularity classification were also used for comparison with the performance of our proposed model. To assess the classifier's performance accuracy this study used MovieLens data as an open database. Our empirical results indicate that our proposed model with movie's genre and centrality data has by approximately 0% higher accuracy than other classification models with only movie's genre data. The implications of our results show that our proposed model can be used for improving movie popularity classification accuracy.

• Journal of the Korea Convergence Society
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• v.9 no.2
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• pp.241-250
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• 2018

Online recruitment services have emerged as one of the most popular Internet services, providing job seekers with a comprehensive list of jobs and a search engine. But many recruitment services suffer from shortcomings due to their reliance on traditional client-pull information access model, in manay cases resulting in unfocused search results. Worldjob+, being operated by The Human Resources Development Service of Korea, addresses these problems and uses Splunk, a platform for analyzing machine data, to provide a more proactive and personalised services. It focuses on enhancing the existing system in two different ways: (a) using personalised automated matching techniques to proactively recommend most preferrable profile or specification information for each job opening announcement or recruiting company, (b) and to recommend most preferrable or desirable job opening announcement for each job-seeker. This approach is a feature-free recommendation technique that recommends information items to a given user based on what similar users have previously liked. A brief discussion about the potential benefit is also provided as a conclusion.

• Wind and Structures
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• v.2 no.3
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• pp.133-150
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• 1999

Significant costs to the public and private sectors due to recent extreme wind events have motivated the need for systematic post-hurricane damage data collection and analysis. Current post disaster data are collected by many different interested groups such as government agencies, voluntary disaster relief agencies, representatives of media companies, academicians and companies in the private sector. Each group has an interest in a particular type of data. However, members of each group collect data using different techniques. This disparity in data is not conducive to quantifying damage data and, therefore, inhibits the statistical and spatial description of damage and comparisons of damage among different extreme wind events. The data collection does not allow comparisons of data or results of analyses within a group and also prohibits comparison of damage data and information among different groups. Typically, analyses of data from a given event lead to different conclusion depending upon the definition of damage used by individual investigators and the type of data collected making it difficult for members of groups to compare the results of their analyses with a common language and basis. A formal method of data collection and analysis-within any single group-would allow comparisons to be made among different individuals, hazardous events and eventually among different groups, thus facilitating the management and reduction of damage due to future disaster. This research introduces a definition of damage to single family dwellings, and a common method of data collection and analysis suited for groups interested in regional characterization of damage. The current state-of-data is presented and a method for data collection is recommended based on these existing data collection methods. A fixed-scale damage index is proposed to consider the damage to a dwelling's feature. Finally, the damage index is applied to three dwellings damaged by Hurricane Iniki (1992). The damage index reflects the reduced functionality of a structure as a single family detached dwelling and provides a means to evaluate regional damage due to a single event or to compare damage due to events of different severity. Evaluation of the damage index and the data available support recommendation for future data collection efforts.

• Korean Journal of Cleft Lip And Palate
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• v.4 no.2
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• pp.1-8
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• 2001

The dissimilarities between South and North Korea have persisted in spite of the reconciliation campaign by both countries. The situation of the cleft lip & palate of North Korea was very unclear until now. The purpose of this study is to understand all the current facts of cleft lip & palate in North Korea so that we can find ways of helping North Korea in this field of medicine. The present data and analysis are extracted from North Korean textbooks. The results are as follow. 1. In North Korea, patients with CLP are treated by oral surgeons or maxillofacial surgeons. The detailed contents about the CLP are well described in the North Korean textbooks for the dental students. 2. The terminology of CLP in North Korea has changed from time to time, but the present terminology not being so different from South Korean counterpart. So there will be no particular problems in mutual communication. 3. The main classification for CLP in North Korea originated from Kernahan & Stark's classification as is with South Korea. 4. The incidence of CLP is 1 : 1,000-1,200 in North Korea, which is lower than that of South Korea. There is, however, some difference between the North and South Korean CLP in detailed statistics. 5. We found the North Korean physicians have shown much interest in pursuing the etiology and the prevention of CLP. 6. The timing of CLP operations varied a lot in North Korea. There was recommendation by few for the operation in much late age than in South Korea. 7. The classical operation techniques of cleft lip have changed. For unilateral cleft lip Tennison-Randall method was replaced by Millard I method: and for bilateral cleft lip LeMesurier method was replaced by Veau III and Tennison methods. But for cleft palate Pushback palatoplasty has been utilized consistently.

• Journal of the Korean Society for Nondestructive Testing
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• v.22 no.1
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• pp.32-37
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• 2002

The presence of hydrogen in industrial plants is a source of damage. Hydrogen attack is one such form of degradation and often causing large tube ruptures that necessitate an immediate shutdown. Hydrogen attack may reduce the fracture toughness as well as the strength of steels. This reduction is caused partially by the presence of cavities and microcracks at the grain boundaries. In the past several techniques have been used with limited results. This paper describes the application of an ultrasonic velocity and attenuation in hydrogen damage. Ultrasonic tests showed a decrease in wave velocity and an increase in attenuation. Such results demonstrate the potential for ultrasonic nondestructive testing to quantify damage. Based on this study, reliable recommendation is suggested to detect hydrogen attack.