• Journal of the Korean Society of Radiology
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• v.81 no.2
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• pp.310-323
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• 2020

To treat congenital heart disease, it is important to understand the anatomical structure correctly. Three-dimensional (3D) printed models of the heart effectively demonstrate the structural features of congenital heart disease. Occasionally, the exact characteristics of complex cardiac malformations are difficult to identify on conventional computed tomography, magnetic resonance imaging, and echocardiography, and the use of 3D printed models can help overcome their limitations. Recently, 3D printed models have been used for congenital heart disease education, preoperative simulation, and decision-making processes. In addition, we will pave the way for the development of this technology in the future and discuss various aspects of its use, such as the development of surgical techniques and training of cardiac surgeons.

• Nuclear Engineering and Technology
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• v.56 no.7
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• pp.2875-2880
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• 2024

The development of nuclear power plants is in three phases. The first phase is a consideration before the decision on the NPP construction program is approved, the second phase is the preparatory work for making contracts and preparing for the construction of NPP after the NPP construction policy is approved, and the third phase is contracting, licensing and building the first NPP. As a volcanically active country, Indonesia contains over 130 active volcanoes that are part of the Pacific Ring of Fire. The volcanic aspect is one of the safety factors considered while deciding the location of an NPP. Research on the potential of natural external risks to the determination of nuclear power plants in Indonesia, including the volcanic aspect, has been conducted based on the safety reference or safety guide of the IAEA and the Nuclear Energy Regulatory Body (BAPETEN) Regulation. Due to technological advancements, safety needs have evolved so the existing Indonesia National Standard (SNI) must be updated to comply with BAPETEN regulations. The substance in SNI 18-2034-1990 relating to volcanic features seems less relevant in actual conditions, given that more complete and exact criteria for determining a site guarantee the safety and health of residents and surrounding the environment site. The study intends to conduct a gap analysis of volcanic issues in SNI and volcanic regulations. The method used is identification requirements for volcanic aspects in SNI 18-2034-1990 about Determining Site of Nuclear Reactor Guidance with BAPETEN Chairman Regulation (BCR) number 4 of 2018 about Nuclear Installation Site Evaluation Safety Provisions and BCR number 5 of 2015 about Evaluation of Nuclear Installation Sites for Volcanic Aspects, and analysis uses a qualitative method of inductive techniques. The outcome of this research applies to suggesting a revision of SNI number 18-2034-1990, especially the volcanic aspect.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.27 no.5
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• pp.13-25
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• 2024

With the increasing wildfire damage driven by climate change, it is crucial to assess the effectiveness of restoration efforts on a large scale. The majority of forests in Korea are situated in rugged mountainous regions, making it challenging to monitor large-scale wildfires. Consequently, establishing methodologies that use satellite imagery to evaluate restoration effectiveness is essential. This study aims to assess the recovery trends of ecosystems in wildfire-affected areas using NDVI mean-variance plots, which monitor changes in NDVI mean and variance over time through satellite imagery and visually represent the restoration process. The analysis of NDVI mean-variance plots for different restoration methods revealed that landscape restoration had the slowest recovery. This slower recovery is likely due to reduced growth from the complete removal of damaged trees. In contrast to High Severity (HS) areas, Moderate High Severity (MHS) areas showed that commercial afforestation, revegetation, ecological forest treatment led to a more stable recovery state post-disturbance, suggesting that areas with lower wildfire severity may recover more quickly. Furthermore, the recovery trends between artificial and natural restoration showed no significant difference, indicating that natural restoration can have similar restoration effects to artificial restoration in appropriate areas. Therefore, the study emphasizes the need to expand natural restoration areas, considering ecological and economic benefits such as increased biodiversity and genetic resource conservation. This research provides critical baseline data for the formulation and implementation of restoration policies in large-scale wildfire-affected regions and is expected to contribute significantly to the development of effective management strategies and monitoring techniques.

• Journal of the Korean Society for Library and Information Science
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• v.7
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• pp.89-195
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• 1980

The advanced developing countries including Korea are assumed to have reached a developmental stage which necessitates them to formulate and implement a plan for a national information network. Most of the governments in the advanced developing countries are well aware of the necessity for such a plan and some of them have actually commenced their studies on the feasibility of a national network of their own hoping to achieve maximum utility of their limited information resources. Two urgent problems facing planners in the design of a national information network are identified. One is lack of an optimum organisational model to enable them to meet their own situations, and the other is lack of a guideline to help designers evaluate the alternative structures and models when they are available. In resolving these two problems, network planners in the advanced developing countries would benefit from the achievement of the objectives of the present study. The major objective is to elicit and describe common information needs, desires and value of the people using information, and other common factors which are responsible for the present information services in the advanced developing countries and which have implications for the basic structure of the national information network. The value of this study is to aid administrators in Korea and those in the other advanced developing countries who are responsible for making national policies and who are now beginning to recognise the need for information services with the planning of economic and social development so as to enable all the groups in the community to have access to the information which are essential for decision making, research work, studies and even for recreational reading. This recognition will hopefully give them a rational basis for formulating right policies on information services. The methodology utlised for collecting the required data in this study falls under the category of observation and largely consists of the two techniques: literature review and postal questionnaire. Background information on the individual advanced developing: countries was gathered from monographic and periodical literature. and country reports presented at the various international conferences were analysed for other relevant data. For most of the data needed for the present study, a questionnaire on 'Library and Information Services as They Are Available in the Selected Countries' was formulated. This questionnaire was designed to be completed without help, by an expert who was well informed of the library and information services in his or her country. The questionnaire was intended to look in details at what information services in the advanced developing countries were doing-whom they were serving, in what way, and how well and establish to what extent they were meeting the nation's information requirements. It was also intended to ascertain the respondents' ideas on possible future developments in information provision in their countries, that is, in the advanced devanced developing countries. The questionnaire was posted to a total of 63 natinal librarians, directors of national information centres and those of other major libraries or information centres in 21 selected countries. Complete usable responses were received from 34 persons in 14 countries. In order to identify common characteristics of the information needs and desires in the advanced developing countries and the present situation of the information services to meet them, and the requirements and constraints peculiar to those countries which bought to be considered in the design of a national information network for advanced developing countries, an individual report on the current status of information activities for each of the fourteen countries chosen for this study, was presented. The procedure used was to arrange the data acquired in the questionnaire responses and other sources, in the form of fifteen country reports to be summarised by cross-section characteristics later.

• Journal of Intelligence and Information Systems
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• v.24 no.2
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• pp.1-19
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• 2018

Since stock movements forecasting is an important issue both academically and practically, studies related to stock price prediction have been actively conducted. The stock price forecasting research is classified into structured data and unstructured data, and it is divided into technical analysis, fundamental analysis and media effect analysis in detail. In the big data era, research on stock price prediction combining big data is actively underway. Based on a large number of data, stock prediction research mainly focuses on machine learning techniques. Especially, research methods that combine the effects of media are attracting attention recently, among which researches that analyze online news and utilize online news to forecast stock prices are becoming main. Previous studies predicting stock prices through online news are mostly sentiment analysis of news, making different corpus for each company, and making a dictionary that predicts stock prices by recording responses according to the past stock price. Therefore, existing studies have examined the impact of online news on individual companies. For example, stock movements of Samsung Electronics are predicted with only online news of Samsung Electronics. In addition, a method of considering influences among highly relevant companies has also been studied recently. For example, stock movements of Samsung Electronics are predicted with news of Samsung Electronics and a highly related company like LG Electronics.These previous studies examine the effects of news of industrial sector with homogeneity on the individual company. In the previous studies, homogeneous industries are classified according to the Global Industrial Classification Standard. In other words, the existing studies were analyzed under the assumption that industries divided into Global Industrial Classification Standard have homogeneity. However, existing studies have limitations in that they do not take into account influential companies with high relevance or reflect the existence of heterogeneity within the same Global Industrial Classification Standard sectors. As a result of our examining the various sectors, it can be seen that there are sectors that show the industrial sectors are not a homogeneous group. To overcome these limitations of existing studies that do not reflect heterogeneity, our study suggests a methodology that reflects the heterogeneous effects of the industrial sector that affect the stock price by applying k-means clustering. Multiple Kernel Learning is mainly used to integrate data with various characteristics. Multiple Kernel Learning has several kernels, each of which receives and predicts different data. To incorporate effects of target firm and its relevant firms simultaneously, we used Multiple Kernel Learning. Each kernel was assigned to predict stock prices with variables of financial news of the industrial group divided by the target firm, K-means cluster analysis. In order to prove that the suggested methodology is appropriate, experiments were conducted through three years of online news and stock prices. The results of this study are as follows. (1) We confirmed that the information of the industrial sectors related to target company also contains meaningful information to predict stock movements of target company and confirmed that machine learning algorithm has better predictive power when considering the news of the relevant companies and target company's news together. (2) It is important to predict stock movements with varying number of clusters according to the level of homogeneity in the industrial sector. In other words, when stock prices are homogeneous in industrial sectors, it is important to use relational effect at the level of industry group without analyzing clusters or to use it in small number of clusters. When the stock price is heterogeneous in industry group, it is important to cluster them into groups. This study has a contribution that we testified firms classified as Global Industrial Classification Standard have heterogeneity and suggested it is necessary to define the relevance through machine learning and statistical analysis methodology rather than simply defining it in the Global Industrial Classification Standard. It has also contribution that we proved the efficiency of the prediction model reflecting heterogeneity.

• Journal of the Society of Disaster Information
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• v.13 no.2
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• pp.233-248
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• 2017

Uniform laws and regulations and reasonable design is necessary for the prevention of possible fire in super high-rise building. To this end, this study focused on super high-rise and massive building-related architectural review performance-based design (PBD) evaluation disaster impact assessment (DIA), and provided fire engineering measures for improving fire prevention on the basis of performance-based design by analyzing the buildings subject to these systems and problems in terms of contents. Above all, in the aspect of law and standard improvement, first, with regard to dual parts of two statutes though significant portion of them has the same contents in performance-based design (PBD) evaluation and disaster impact assessment (DIA), it is necessary to operate the systems after making them conform with each other and consolidating or abolishing them. Second, if it is impossible to consolidate or abolish performance-based design (PBD) evaluation and disaster impact assessment (DIA), the areas of contents of performance-based design (PBD) evaluation and disaster impact assessment (DIA) should be precisely classified and established. Next, engineering improvement measures against fire hazard in super high-rise building are as follows. First, it is necessary to revise the provisions of straight-run stairs in special escape stairs. And in case of installing a mechanical smoke exhaust system instead of smoke vent, sandwich pressurization used in the United Stated should be permitted. Second, with regard to smoke control system for special escape stairs, it was shown that there was necessity for revising the standards in order to enable air to be supplied according to section in case of fire, carrying out performance-based design, and the like from the early design stages to the completion stages. In the future, it is expected that an epoch-making contribution will be made to a decrease in casualties and property damage due to fire in case of super high-rise building where the results can be reflected after carrying out a study on maintenance and carrying out an additional study on other considerations of super high-rise building together with reflecting the improvement measures provided in the above-mentioned study.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.6
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• pp.1634-1647
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• 2007

"To invest or not to invest?" Most business leaders are frequently faced with this question on new and ongoing projects. The challenge lies in deciding what projects to choose, expand, contract, defer, or abandon. The project valuation tools used in this process are vital to making the right decisions. Traditional tools such as discounted cash flow (DCF)/net present value (NPV) assume a "fixed" path ahead, but real world projects face uncertainties, forcing us to change the path often. Comparing to other traditional valuation methods, the real options approach captures the flexibility inherent to investment decisions. The use of real options has gained wide acceptance among practitioners in a number of several industries during the last few decades. Even though the options are present in all types of business decisions, it is still not considered as a proper method of valuation in some industries. Mining has been comparably slow to adopt new valuation techniques over the years. The reason fur this is not entirely clear. One possible reason is the level and types of risks in mining. Not only are these risks high, but they are also more numerous and involve natural risks compared with other industries. That is why the purpose of this study is to deal with a more practical approach to project valuation, known as real options analysis in mining industry. This paper provides a case study approach to the copper mining industry using a real options analysis. It shows how companies can minimize investment risks, exercise flexibility in decision making and maximize returns.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2000.06a
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• pp.16-23
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• 2000

The increasing functional needs of top-quality printing papers and packaging paperboards, and especially the rapid developments in electronic printing processes and various computer printers during past few years, set new targets and requirements for modern paper quality. Most of these paper grades of today have relatively high filler content, are moderately or heavily calendered , and have many coating layers for the best appearance and performance. In practice, this means that many of the traditional quality assurance methods, mostly designed to measure papers made of pure. native pulp only, can not reliably (or at all) be used to analyze or rank the quality of modern papers. Hence, introduction of new measurement techniques is necessary to assure and further develop the paper quality today and in the future. Paper formation , i.e. small scale (millimeter scale) variation of basis weight, is the most important quality parameter of paper-making due to its influence on practically all the other quality properties of paper. The ideal paper would be completely uniform so that the basis weight of each small point (area) measured would be the same. In practice, of course, this is not possible because there always exists relatively large local variations in paper. However, these small scale basis weight variations are the major reason for many other quality problems, including calender blacking uneven coating result, uneven printing result, etc. The traditionally used visual inspection or optical measurement of the paper does not give us a reliable understanding of the material variations in the paper because in modern paper making process the optical behavior of paper is strongly affected by using e.g. fillers, dye or coating colors. Futhermore, the opacity (optical density) of the paper is changed at different process stages like wet pressing and calendering. The greatest advantage of using beta transmission method to measure paper formation is that it can be very reliably calibrated to measure true basis weight variation of all kinds of paper and board, independently on sample basis weight or paper grade. This gives us the possibility to measure, compare and judge papers made of different raw materials, different color, or even to measure heavily calendered, coated or printed papers. Scientific research of paper physics has shown that the orientation of the top layer (paper surface) fibers of the sheet paly the key role in paper curling and cockling , causing the typical practical problems (paper jam) with modern fax and copy machines, electronic printing , etc. On the other hand, the fiber orientation at the surface and middle layer of the sheet controls the bending stiffness of paperboard . Therefore, a reliable measurement of paper surface fiber orientation gives us a magnificent tool to investigate and predict paper curling and coclking tendency, and provides the necessary information to finetune, the manufacturing process for optimum quality. many papers, especially heavily calendered and coated grades, do resist liquid and gas penetration very much, bing beyond the measurement range of the traditional instruments or resulting invonveniently long measuring time per sample . The increased surface hardness and use of filler minerals and mechanical pulp make a reliable, nonleaking sample contact to the measurement head a challenge of its own. Paper surface coating causes, as expected, a layer which has completely different permeability characteristics compared to the other layer of the sheet. The latest developments in sensor technologies have made it possible to reliably measure gas flow in well controlled conditions, allowing us to investigate the gas penetration of open structures, such as cigarette paper, tissue or sack paper, and in the low permeability range analyze even fully greaseproof papers, silicon papers, heavily coated papers and boards or even detect defects in barrier coatings ! Even nitrogen or helium may be used as the gas, giving us completely new possibilities to rank the products or to find correlation to critical process or converting parameters. All the modern paper machines include many on-line measuring instruments which are used to give the necessary information for automatic process control systems. hence, the reliability of this information obtained from different sensors is vital for good optimizing and process stability. If any of these on-line sensors do not operate perfectly ass planned (having even small measurement error or malfunction ), the process control will set the machine to operate away from the optimum , resulting loss of profit or eventual problems in quality or runnability. To assure optimum operation of the paper machines, a novel quality assurance policy for the on-line measurements has been developed, including control procedures utilizing traceable, accredited standards for the best reliability and performance.

• Korean Journal of Heritage: History & Science
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• v.52 no.1
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• pp.4-21
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• 2019

In this paper, 23 Silla gold earrings from the sixth and seventhand centuries, excavated from the Yeongnam region, were analyzed. Based on the silver content of the gold plate, they were classified into three types. The classifications included type I(20-50wt%), type II(10-20wt%) and type III (less than 10wt%). In the analysis process, the composition and morphological differences were identified on the surface of the gold plate. In the case of type I and II earrings, it was observed that the fine holes were concentrated in a relatively higher part of the gold content. The causes of the difference in the surface composition of the gold plate were divided into four categories: 1) surface treatment, 2) thermal diffusivity in the manufacturing process, 3) differences in composition of alluvial gold, and 4) the refining method of gold. It is possible that depletion gilding was attempted to increase the gold content while intentionally removing the other metals from the surface of the gold alloy in the portion where the gold deposit is relatively concentrated on the surface of the gold plating. The highest copper content was detected in the earring with the highest gold content of the analyzed earrings, and it was assumed that thermal diffusion had occurred between the gold plate and the metal rod during the manufacturing process rather than intentional addition. Copper was detected only in the thin ring earring type, and copper was not detected in the thick ring earring type or pendant type. It also proves that this earring has a high degree of tightness at higher temperatures, as there was an invisible edge finish on other earrings and horizontal wrinkles on the gold plate surface. In terms of the material of the gold plate, we examined whether the silver content of the gold plate was natural gold or added by alloy through analyzing the alluvial gold collected in the region. As a result of the analysis, it was found that on average about 13wt% of silver is included. This suggests that type II is natural gold, type III is refined gold, and type I seems to have been alloyed with natural gold. Here, we investigated the refining method introduced in the ancient literature, both at home and abroad, about the possibility of alloying silver after the refining process of type III earrings and then making pure gold. It was found that from ancient refining methods, silver which had been present in the natural gold was removed by reacting and combining with silver chloride or silver sulfide, and long-term efforts and techniques were required to obtain pure gold through this method. Therefore, it was concluded that the possibility of adding a small amount of silver in order to increase strength after making pure gold through a refining process is low.

• Korean Journal of Heritage: History & Science
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• v.43 no.3
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• pp.334-365
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• 2010

Mother-of-Pearl craftwork sketch involves the whole process of making a piece of work. Therefore, it includes types, forms, sizes, and patterns of the work. Some information about when and by whom those works were manufactured and who ordered them are still found in some sketches. This paper seeks to find out popular types and patterns of the works in each period and its demand and the way of supply by examining the collection of approximately 1700 Mother-of-Pearl craftwork sketches from the period of Japanese colonization up to the present time, which are owned by Mr. Song Bang-wung, Important Intangible Cultural Heritage no.10. Typical patterns of sketches are the hua-jo(花鳥 : Flowers and Birds), the Sakunja(四君子 : Four Gracious Plants), cultural treasures, figures in folk tales, 'Su-bok(壽福)' characters, and landscape. The pattern sketches have changed according to the circumstances of Korean society. During the period of Japanese colonization from the 1920s to the 1940s the manufacture and the supply and demand of Mother-of-Pearl craftworks were controled by the Japanese government. As a result, many of the patterns were adjusted to the Japanese taste. Most of its customers were also Japanese. During the 1950s after Independence the American Military Forces appeared as new customers due to the Korean War. Thus, the traditional Korean patterns to decorate accessories adored by American soldiers gained popularity. Foreign Mother-of-Perls were imported from the late 1960s to the 1970s. They were bigger and more colorful than those of Korean and it enabled the sketches bigger and the patterns more various. The most popular pattern in this period was the pattern of cultural treasures, such as an image of Buddha, metalcraft works, porcelains and pagodas. In terms of a technique, new techniques, such as engraving and rusting were introduced. There was a great demand for Mother-of-Pearl craftworks in the 1970s as people were highly interested in them. They were entirely made to order and there was a large demand from diverse organizations, furniture dealers and individuals. And the Mother-of-Pearl craftwork was in full flourish in the 1970s due to the country's economic development and the growth of national income. Mass production of the works was possible and the professional designers who drew patterns actively worked in this period. The favor of Mother-of-Pearl craftworks declined in the 1980s since the built-in furniture and the Western style of furniture became prevalent due to the change of housing into apartments. But it seemed that the manufacture of Mother-of-Pearl craftworks revived for once the technique of Kunum-jil(끊음질 : cutting and attaching) became popular in Tong-young(統營). After the 1990s, however, the making of Mother-of-Pearl craftworks gradually declined as the need of them decreased. Now it barely maintains its existence by a few artisans.