• The Korean Journal of Applied Statistics
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• v.36 no.1
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• pp.101-101
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• 2023

• Journal of Internet Computing and Services
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• v.10 no.2
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• pp.99-116
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• 2009

For the mapping of two dimensional table structures of relational databases to the hierarchical XML documents, we apply the foreign key relationships of relational databases. In other words, the primary key of another table referenced by a foreign key of one tuple is mapped to the parent of the foreign key. Then XML hierarchies with order are expressed. In addition, the XML view file generated by the foreign key mappings shows side effects in the case of the relational database update for the satisfaction of referential integrity constraint in the foreign key. Thus, by inferring the foreign key roles at the generation of XML hierarchies, we can anticipate where the side effects occur in the hierarchies. We keep the XML view files up-to-date by reflecting the side effects to the XML files at the update of the underlying relational databases.

• Journal of Computing Science and Engineering
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• v.4 no.4
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• pp.276-290
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• 2010

The join operator is fundamental in relational database systems. Evaluating join queries on large tables is challenging because records need to be efficiently matched based on a given key. In this work, we analyze join queries in SQL with large tables in which a foreign key may be null, invalid or valid, given a referential integrity constraint. We conduct an extensive join performance evaluation on three DBMSs. Specifically, we study join queries varying table sizes, row size and key probabilistic distribution, inserting null, invalid or valid foreign key values. We also benchmark three well-known query optimizations: view materialization, secondary index and join reordering. Our experiments show certain optimizations perform well across DBMSs, whereas other optimizations depend on the DBMS architecture.

• Journal of Korean language education
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• v.29 no.2
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• pp.25-48
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• 2018

The aim of this study was to analyze research trends in the fields of Korean Language and Literature, Korean Language Education, and Korean Language Education as a Foreign Language. To this end, key words were extracted from 29,470 academic theses published between 2000 and 2017. The results of the analysis are as follows. First, in the field of Korean Language and Literature, there is greater quantity in studies about Korean language than about literature, and starting from 2010, there was an increase in studies similar to those from the field of Korean Language Education as a Foreign Language. Next, in comparison to the other fields, the field of Korean Language Education has greater variance in its research theme-in particular, numerous studies related to the site of education. Finally, the field of Korean Language Education has the following trends: a) there are copious studies focused on Korean language learners in comparison to other fields, b) there are a greater number of studies focused on culture, and c) the key words change by time period which suggest that research demands transformed over time. Overall, a total of 64 highest frequency key words from the three academic fields were investigated. Of these, 22 were common key words and 42 were differential key words. In this way, it was possible to illuminate the identity of each field.

• Journal of the Korean School Mathematics Society
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• v.15 no.1
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• pp.81-108
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• 2012

One of the keyword in every nation's recent educational policy is key competencies. Considering national competitiveness originating from educational competitiveness, educational policy has been driven to identify key competencies and realize them through school education. Within this context some countries have developed competencies-based curriculum and discussed ways to relate key competencies and subject matter areas. However, there have been few researches on how to reflect or integrate key competencies into subject matter areas. Because of this reason, the ways to incorporate and integrate key competencies into three subject areas including mathematics were investigated. The recent trends of curriculum, teaching and learning, and assessment of domestic and foreign cases were explored by the subject of one Korean international middle school, one British foreign school in Seoul, one French foreign school in Seoul, and four middle schools in New Zealand. To establish competencies-based school education, there should be intimate connection system among curriculum, teaching and learning, assessment, and teacher education. Through analysis of domestic and foreign cases, some conclusions regarding how these aspects have changed with the emphasis of key competencies were drawn. In this paper, through classroom observation and teacher interview, a case of the competencies-based mathematics lessons of one French foreign school was investigated. As a result, summaries and recommendations related to ways to improve subject teaching and teacher education in light of key competencies were presented. In these recommendations, the ways to reconstruct subject-based curriculum, the content-specific teaching and learning, and educational assessment were included.

• Journal of the Korean Society of Clothing and Textiles
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• v.36 no.1
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• pp.27-35
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• 2012

This study locates typical Korean fashion images in domestic and foreign fashion journals to advance Korea's international image in contemporary global fashion markets. The investigation of the frequency of articles and their types (so as to inquire into interest in Korean fashion in the global fashion markets) showed that for the appearance frequency of domestic articles studied, a good number of articles were published in the first half of 2008 and in 2009. In the case of foreign articles, the number of them increased from the second half of 2008 and the majority of articles were shown in the first half of 2010. Second, the investigation of the appearance features by article type studied in order to understand how Korean fashion played a role in the world's markets. The majority of articles were related to fashion brands that entered Chinese market in fashion brand articles in the case of domestic articles; however, many foreign articles introduced designers that participated in global fashion collections in Paris and New York. Third, as a result of analyzing typical key words by article type in order to find key words which could enhance Korea's fashion national image representing, we could confirm that 'Korean designers' can be a typical key words to represent Korean fashion. The key word most exposed in both domestic and foreign articles was 'designer Lie Sang Bong' and only his articles contained the content about influential Korean design materials.

• KSCI Review
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• v.14 no.2
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• pp.185-197
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• 2006

A star schema consists of a central fact table, which is surrounded by one or more dimension tables. Each row int the fact table contains a multi-part primary key(or a composite foreign key) along with one or more columns containing various facts about the data stored in the row Each of the composit foreign key components is related to a dimensional table. The combination of keys in the fact table creates a composite foreign key that is unique to the fact table record. The composite foreign key, however, is rarely unique to the fact table record in real-world applications, particularly in financial applications. In order to make the composite foreign key be the determinant in real-world application, some precalculation might be performed in the SQL relational database, and cached in the OLAP database. However, there are many drawbacks to this approach. In some cases, this approach might give users the wrong results. In this paper, an approach to fact table modeling and related MDX query composing, which can be used in real-world applications without performing any precalculation and gives users the correct results, is proposed.

• Journal of the Korea Society of Computer and Information
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• v.12 no.1 s.45
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• pp.177-188
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• 2007

A star schema consists of a central fact table, which is surrounded by one or more dimension tables. Each row in the fact table contains a multi-part primary key(or a composite foreign key) along with one or more columns containing various facts about the data stored in the row. Each of the composit foreign key components is related to a dimensional table. The combination of keys in the fact table creates a composite foreign key that is unique to the fact table record. The composite foreign key, however, is rarely unique to the fact table retold in real-world applications, particularly in financial applications. In order to make the composite foreign key be the determinant in real-world application, some precalculation might be performed in the SQL relational database, and cached in the OLAP database. However, there are many drawbacks to this approach. In some cases, this approach might give users the wrong results. In this paper, an approach to fact table modeling and related MDX query composing, which can be used in real-world applications without performing any precalculation and gives users the correct results, is proposed.

• Proceedings of the Korea Contents Association Conference
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• 2003.11a
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• pp.132-139
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• 2003

In this paper, we design and implement the public key certification the structure of assure information security which play an important role in PKI (Public Key Infrastructure). The structure of assure information security consists of Root-CA, Home-network and Foreign-network. CA will going to gave the mandate to Home-Agent or Foreign-Agent when they request. The structure of assure information security is various characteristic : more then high speed, mobile network, and low cost more then previous structure of assure information security.

• Journal of Korean Institute of Industrial Engineers
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• v.37 no.3
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• pp.264-270
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• 2011

A new method for creating a logical data model is proposed. The logical data model developed by the method defines table, primary key, foreign key, and fields. The framework of the logical data model is constructed by modeling the relationships between events and their related entity types. The proposed method consists of a series of objective and quantitative decisions such as maximum cardinality of relationships and functional dependency between the primary key and attributes. Even beginners to database design can use the methology as long as they understand such basic concepts about relational databases as primary key, foreign key, relationship cardinality, parent-child relationship, and functional dependency. The simple and systematic approach minimizes decision errors made by a database designer. In practial database design the method creates a logical data model in Boyce-Codd normal form unless the user of the method makes a critical decision error, which is very unlikely.