• Journal of Korea Multimedia Society
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• v.6 no.5
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• pp.876-888
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• 2003

The U.S., Japan and Korea have realized the importance of establishing standards for eBook document formats and with government bodies, related industries and academic circles, OEB PS, JepaX and EBKS were established. However, compared to OEB of the U.S. and JepaX of Japan, EBKS contains different objective for establishment and different structures. As a result, for converting between documents of different standards, exact analysis of the document structures are called for and minimization of information loss when actually converting documents is required. Therefore, a method for explicit exchange between documents of different standards minimizing document structure is proposed and examples are looked at. As a result, in this paper, conversion possibilities between EBKS and OEB/JepaX are introduced and the result can be applied to cases when exchanging eBook standards and other formats.

• Journal of Information Technology Services
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• v.19 no.2
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• pp.109-124
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• 2020

Facing the 4^th Industrial Revolution era, researches on artificial intelligence have become active and attempts have been made to apply machine learning in various fields. In the field of finance, Robo Advisor service, which analyze the market, make investment decisions and allocate assets instead of people, are rapidly expanding. The stock price prediction using the machine learning that has been carried out to date is mainly based on the prediction of the market index such as KOSPI, and utilizes technical data that is fundamental index or price derivative index using financial statement. However, most researches have proceeded without any explicit verification of the prediction rate of the learning data. In this study, we conducted an experiment to determine the degree of market prediction ability of basic indicators, technical indicators, and system risk indicators (AR) used in stock price prediction. First, we set the core parameters for each financial indicator and define the objective function reflecting the return and volatility. Then, an experiment was performed to extract the sample from the distribution of each parameter by the Markov chain Monte Carlo (MCMC) method and to find the optimum value to maximize the objective function. Since Robo Advisor is a commodity that trades financial instruments such as stocks and funds, it can not be utilized only by forecasting the market index. The sample for this experiment is data of 17 years of 1,500 stocks that have been listed in Korea for more than 5 years after listing. As a result of the experiment, it was possible to establish a meaningful trading strategy that exceeds the market return. This study can be utilized as a basis for the development of Robo Advisor products in that it includes a large proportion of listed stocks in Korea, rather than an experiment on a single index, and verifies market predictability of various financial indicators.

• The Transactions of the Korea Information Processing Society
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• v.5 no.5
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• pp.1246-1256
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• 1998

MIB(Management Information Base), one of the key components of network management system, is a conceptual repository for the information of the various managed objects. MIB stores and manages all the structural and operational data of each managed resources. Therefore, MIB should be protected properly from inadvertant user access or malicious attacks. International standard ISO/IEC 10164-9 describes several managed object classes for the enforcement of MIB security. Those managed object classes described access control rules for security policy. But the exact authorization procedures using those newly added managed object classes are not presented. In this paper, we divide managed object classes into two groups, explicit and implicit ones, and describe the access authorization procedure in Z specification language. Using Z as a description method for both authorization procedure and GDMO's action part, the behaviour of each managed object class and access authorization procedure is more precisely and formally defined than those of natural language form.

• Journal of Surface Science and Engineering
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• v.41 no.6
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• pp.255-263
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• 2008

Generally, deposition mechanism of diamond particle is mainly embedding effect in the kinetic spray process. Accordingly, in spite of high cost, helium gas was employed as process gas to get high diamond fraction in the composite coating. In this study, the deposition behavior of bronze/diamond by kinetic spray process was compared using different process gas (helium and nitrogen). Bare (mean size of $5{\mu}m$, $20{\mu}m$) and nickel coated diamond (mean size of $26{\mu}m$) were deposited on Al 6061-T6 substrate with fixed process temperature and pressure. For comparison with experimental results, plastic deformation behavior of nickel layer was simulated by finite element analysis (using ABAQUS/Explicit 6.7-2). The size, broken ratio, and fraction of diamond in the composite coating were analyzed through scanning electron microscopy and image analysis method. The uniform distribution and deposition efficiency of diamond particles in the coating layer could be achieved by tailoring the physical properties of the feedstock.

• Composites Research
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• v.28 no.2
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• pp.58-64
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• 2015

The purpose of this paper is to suggest the effective equivalent finite element model for the impact limiter of a nuclear spent fuel shipping cask made of sandwich composite panels. The sandwich composite panels were composed of a metallic facesheet and a core material made of urethane foam, balsa wood and red wood, respectively. The effective equivalent finite element model for the impact limiter was proposed by comparing the results of low-velocity impact test of sandwich panels. An explicit finite element analysis based on LS-DYNA 3D was done in this study. The results showed that the solid elements were recommended to model the facesheet and core of sandwich panels for impact limiter compared to combination modeling method, in which the layered shell element for facesheet and solid element for core material are used. In particular, the solid element for balsa and red wood core materials should be modeled by the element elimination approach.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.1 no.1
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• pp.22-30
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• 1989

Wave propagation is changed by the effect of shoaling, current-depth refraction and shelter-ing etc. To solve these problems. numerous models have been developed. In the present study, a coordinate system is proposed based on the wave ray equation with the wave number equation including diffraction effects . The governing equation for the study was derived from the mild slope wave equation in non-steady state, including current effects (Kirby, 1986a) and trans-formed into an orthogonal curvilinear coordinate system on the basis of the wave ray equation. To obtain a numerical solution, an explicit finite difference scheme was used, and solved by the relaxation method. This model was tested for various cases: Firstly a submersed circular shoal and a constant unit depth. Secondly a submerged elliptic shoal on a slope, and finally a breakwater harbour with obliquely incident waves on a slope. The model was found to simulate the experimental results and other theoretical results in wave height and wave angle fairy well, and the applicability of the model around an arbitrary shaped coastal structure was also verified. To demonstrate the general usefullness of the present approach , the model is to be applied to a field situation with a complex bed topography.

• Journal of Korean society of Dental Hygiene
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• v.16 no.5
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• pp.741-750
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• 2016

Objectives: This study aims to identify dentists' opinions about the return to work of the dental hygienists with career interrupted. Convenience sampling was made of 22 dentists with the clinical experience (about 0.25%) of the 4,944 members of Gyeonggi-do Dental Association. Data were collected through an electronic survey using e-mails and telephone interviews and analyzed using the constant comparison method. Methods: Open coding was assigned to the initial data from the survey in an explicit language, and focusing on the types of their employment, working conditions, etc. Summarization and conceptualization were made of the second data in an implicit language. Results: Most of the dentists were found to have positive attitudes toward the return to work of career interrupted dental hygienists and hope to adjust their wages based on their job performance or after their probational period expires. Most of the dentists were found to have positive attitudes towards the hygienists' flexible working although their concerns about work efficiency and hospital atmosphere. This study is a qualitative study that describes dentists' opinions and presents the need for the career interrupted dental hygienists to return to work. Conclusions: The study proposed that the educational institutions should take into account the hygienists' opinions when implementing the programs for promoting their return to work and their evaluative studies.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.5
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• pp.2484-2498
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• 2017

Various types of social media make the people share their personal experience in different ways. In some social networking sites. Some users post their reviews, some users can support these reviews with comments, and some users just rate the reviews as kind of support or not. Unfortunately, there is rare explicit negative comments towards other reviews. This means if there is a link between two users, it must be positive link. Apparently, the negative link is invisible in these social network. Or in other word, the negative links are redundant to positive links. In this work, we first discuss the feature extraction from social media data and propose new method to compute the distance between each pair of comments or reviews on social media. Then we investigate whether we can predict negative links via regression analysis when only positive links are manifested from social media data. In particular, we provide a principled way to mathematically incorporate multi-facet data in a novel framework, Constructing Negative Links, CsNL to predict negative links for discovering the hidden information. Additionally, we investigate the ways of solution to general negative link predication problems with CsNL and its extension. Experiments are performed on real-world data and results show that negative links is predictable with multi-facet of social media data by the proposed framework CsNL. Essentially, high prediction accuracy suggests that negative links are redundant to positive links. Further experiments are performed to evaluate coefficients on different kernels. The results show that user generated content dominates the prediction performance of CsNL.

• The Journal of the Korea Contents Association
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• v.11 no.5
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• pp.67-74
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• 2011

Collaborative recommendation is one of the most widely used methods of automated product recommendation in e-Commerce. For analyzing the customer's preference, traditional explicit ratings are less desirable than implicit ratings because it may impose an additional burden to the customers of e-commerce companies which deals with a number of products. Cardinal scales generally used for representing the preference intensity also ineffective owing to its increasing estimation errors. In this paper, we propose a new way of constructing the ordinal scale-based customer profile for collaborative recommendation. A Web usage mining technique and lexicographic consensus are employed. An experiment shows that the proposed method performs better than existing CF methodologies.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.284-290
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• 2009

As the increased importance is placed on the new transit systems owing to the environmental pollution caused by the road traffic congestion, the policy for the introduction of the new transit systems as an alternative solution to ease the heavy burden of the construction expenses is being actively established. Since the explicit recognition of such transit systems and the review on the method of its adoption have been a pressing matter in the light of reducing the pending traffic congestion, the development of the rolling stock systems in modes of new transportation has been made in various ways taking into consideration the regional circumstances to alleviate traffic congestion, and offer a more efficient service with the application of their intrinsic characteristics. Such systems also have been developed as a mix of punctuality for railway systems operating on the runway and flexibility for buses. This paper, therefore, deals in more detail with 3 modes of systems such as low-floor articulated buses, GRT(Guided Rapid Transit) and tram cars, and studies the overseas cases of the operation of those systems involving both negative and positive aspects.