• Proceedings of the Korean Information Science Society Conference
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• 1999.10a
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• pp.632-634
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• 1999

다양한 소프트웨어 척도들이 절차적 패러다임에서 유용하다는 것이 밝혀졌고 객체지향 패러다임에 대해서도 많은 설계 척도들이 언어 독립적으로 제안되었다. 언어 독립적인 척도로부터 특정 프로그램밍 언어에 대한 척도를 명확하게 하는 것이 중요한데도 불구하고 Java 언어에 대한 척도는 거의 제안되지 않고 있는 형편이다. 따라서 본 논문에서는 Briand가 제안한 속성을 만족하는 척도들과 Java 언어의 특징인 내부 클래스를 반영한 척도와 크기 척도 등 13개의 척도를 Java 프로그램에 적용하여 척도들 사이의 관계를 분석하였다. 클래스의 크기와 메소드 호출 빈도, 응집도, 자식 클래스의 수, 내부 클래스와 상소 계층의 깊이가 주요 인자라는 것을 보여준다. 또한 응집도가 다른 척도들과 음의 관계를 가진다는 것이 발견되었다. 보다 적은 척도를 가지고 인자를 설명할 수 있는 회귀식을 도출하고 교차검증을 실시하였다.

• Journal of the Korea Society of Computer and Information
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• v.15 no.5
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• pp.23-31
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• 2010

With the advances in the information technology and mobile communications, we now face increasing demands for various services based on both of position tracking of moving objects and their efficient index scheme. Accordingly, the $TPR^*$-tree, which were proposed for efficiently tracking moving objects and predicting their positions in the future time, has drawn much intention. As the $TPR^*$-tree came from the R-tree that is suitable for indexing static objects, it does not support cheap update costs. Therefore, it seems to be very costly to index moving objects if there are frequent occurrences of node updates caused by continuously changing velocities and positions. If some moving objects with high velocities have node updates, in particular, then the $TPR^*$-tree may suffer from many unnecessary updates in the wide range of tree regions. To avoid such a problem, we propose a method that can keep fast-moving objects in the child nodes of the root node, thereby saving node update costs in the $TPR^*$-tree. To show our performance advantages and retaining $TPR^*$-tree features, we performed some performance experiments using a simulation technique.

• The Transactions of the Korea Information Processing Society
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• v.5 no.5
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• pp.1185-1203
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• 1998

When the class is added of deleted in object-oriented system, restructuring of class hierarchy is needed which enables new relationship with classes. But existing system requires much additional analysis costs because it is difficult to know the meaning between parent class and child class. This paper presents the updates method based on semantic modification through new relationship classification method. This method measures the similarity of classes and based on it's relationship, this method restructures class hierarchy by classifying not-equality, part-of, equality, inclusion, subset relation. This method can minimize the probability of meaning error for classes when the class hierarchy is changed. Also this enhances the reusability and understandability through various graphic and text processing.

• 한국공간정보시스템학회:학술대회논문집
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• 2005.11a
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• pp.161-167
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• 2005

RFID 태그 객체의 위치정보는 시간에 따라 궤적 정보가 누적되는 이동체와 유사한 특성을 가지지만 태그의 위치는 논리적인 리더의 위치로 인식되며 위치보고가 리더의 인식영역 안에서만 이루어지므로 시간축에 평행한 이산적인 시간간격 형태로 나타나는 차이점이 있다. 기존 이동체의 위치 추적 색인에서는 이동체의 위치를 연결된 다중선으로 표현하여 색인에 저장을 하기 때문에 시공간적으로 연결되지 않은 태그의 위치 정보를 저장하면 궤적 검색 비용이 매우 높아지는 문제가 발생한다. 이 논문에서는 이동체와는 다른 태그의 위치 특성을 반영하여 태그의 궤적 검색을 효율적으로 수행하는 색인 기법을 제안한다. 제안된 색인에서는 시간적으로 연결되지 않은 태그의 궤적 정보를 검색하기 위하여 동일 태그의 위치 간의 연결 정보를 유지하는 기법을 제시하고 있다. 또한, 부모 태그와 자식 태그간의 포함관계를 유지하는 기법을 제시함으로써 상품의 역학조사와 같이 물품에 부착된 태그간의 포함관계를 이용한 순방향 및 역방향 궤적 검색을 효율적으로 수행할 수 있도록 하고 있다.

• Proceedings of the Korea Multimedia Society Conference
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• 2000.11a
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• pp.534-537
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• 2000

지금까지 XML문서는 사용자에게 문서내의 모든 내용을 공개하였지만, 전자상거래와 같은 특정 분야의 경우에는 사용자에 따라 문서의 일부만을 공개하는 것이 필요하다. 따라서, 사용자에게 XML 문서의 권한을 부여하고 권한에 따라 접근을 관리하는 접근 관리 시스템이 요구된다. 이를 위하여 사용자 그룹을 권한 주체의 기본 단위로, XML 문서의 엘리먼트를 권한 객체의 기본 단위로 설정하여야 한다. 그러한 권한 주체의 계층 구조는 DAG(Directed Acyclic Graph) 형태로 표현되고 문서에 대한 접근 권한은 접근 제어 리스트를 이용하여 관리된다. 그러나 권한 주체마다 모든 접근 권한을 표시해야 하기 때문에 엘리먼트 단위의 접근 관리를 위해서는 접근 제어 리스트의 크기가 커지게 되는 문제점이 발생한다. 이를 해결하기 위해서 본 논문에서는 DAG를 완전 k-ary 트리로 변환하여 접근 권한을 부모와 자식 노드간에 상속받을 수 있도록 함으로써 접근 제어 리스트의 크기를 상당히 줄이면서도 권한 주체의 접근 권한이 빨리 알아낼 수 있는 새로운 방법을 제시한다. 성능 분석 결과 새로운 방안이 기존의 전관 제어 리스트에 비해 매우 효과적임을 알 수 있다.

• Journal of the Korea Society of Computer and Information
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• v.15 no.5
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• pp.133-141
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• 2010

Contents adaptation is a technology which converts one content to another content used in various devices. Specially, synchronization of inter-media which are included in a document is needed. There are various proposals and solutions for synchronization of inter-media. In the paper, I present "TATS : Temporal Aggregate Tree Strategy" model, which is used for specifying the temporal relationship among media in series of time. In the TATS model, aggregate tree, a sort of a binary tree, is generated from the execution time of those media. Using this aggregate tree, I implemented the inter-media synchronizations.

• The KIPS Transactions:PartD
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• v.11D no.7 s.96
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• pp.1367-1374
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• 2004

For sharing XML data by many users, a way of concurrency and access control is required for isolating update actions such as inserting and deleting subtrees. Exisiting locking mechanisms as 2PL or MGL suffer low concurrency when applied to tree structures. In this paper, list data subtrees model is proposed based on the semantics expressed in DTD. In this model, tree updating actions such as inserting and deleting subtrees are considered only for the repetitive parts of XML trees. The proposed model guarantees that the result XML tree after applying a tree updating action is always valid, even when multiple users access the tree at the same time. Also, a new locking mechanism called list lock-ing protocol is proposed. The new locking protocol is expected to show better accessility with less number of locking objects compared to the Helmer's OO2PL model. Since update actions on a shared XML tree usually applied to the repetitive parts of the tree, the proposed model is expected to provide a useful way for efficient data sharing when combined with previous locking methods on terminal node data.

• Journal of Korea Multimedia Society
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• v.5 no.1
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• pp.18-27
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• 2002

A hierarchical representation scheme for planar curves, MBO-tree, is proposed in this paper, which provides natural approximation and efficient localization. MBO-tree is based on the Douglas-Peucker algorithm (iterative end-point fit algorithm), but approximation errors that are stored with corresponding points in MBO-tree nodes and are used for abstraction measures are adjusted by force to eliminate unnatural approximation. The error adjusting is just making the approximation error of a node in a MBO-tree to be less than or equal to that of its parent. In point of localization, the bounding area of a curve is represented with a minimum bounding octangle (MBO), which can enclose the curve more compactly compared with those of other hierarchical schemes, such as the strip tree, the arc tree and the HAL tree. The MBO satisfies the hierarchical inclusion property that is useful for hierarchical geometrical operations, such as the point-inclusion test and the polygon intersection test. Through several experiments, we found that the proposed scheme was able to approximate more naturally and to localize more effectively.

• The KIPS Transactions:PartD
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• v.12D no.4 s.100
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• pp.543-552
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• 2005

As random access memory chip gets cheaper, it becomes affordable to realize main memory-based database systems. The disk-based spatial indexing techniques, however, cannot direct apply to main memory databases, because the main purpose of disk-based techniques is to reduce the number of disk accesses. In main memory-based indexing techniques, the node access time is much faster than that in disk-based indexing techniques, because all index nodes reside in a main memory. Unlike disk-based index techniques, main memory-based spatial indexing techniques must reduce key comparing time as well as node access time. In this paper, we propose an efficient spatial index structure for main memory-based databases, called Tmr-tree. Tmr-tree integrates the characteristics of R-tree and T-tree. Therefore, Nodes of Tmr-tree consist of several entries for data objects, main memory pointers to left and right child, and three additional fields. First is a MBR of a self node, which tightly encloses all data MBRs (Minimum Bounding Rectangles) in a current node, and second and third are MBRs of left and right sub-tree, respectively. Because Tmr-tree needs not to visit all leaf nodes, in terms of search time, proposed Tmr-tree outperforms R-tree in our experiments. As node size is increased, search time is drastically decreased followed by a gradual increase. However, in terms of insertion time, the performance of Tmr-tree was slightly lower than R-tree.

• Korean Educational Research Journal
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• v.40 no.2
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• pp.17-33
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• 2019

This study examines the fundamental ethics of practice that Dasan Jung Yak-yong(1762-1836) argued at the book, "Dàxuégōngyì大學公議, The Public debate of Great Learning", by investigating the relationship between main agents of education. "Dàxuégōngyì", the book that Dasan wrote when he was 53 years old at his exiled place, Gangjin. As the title suggested, Dàxuégōngyì, it could be recognized as the impartial view based on the critical perspective to Zhūxǐ(朱憙)'s opinion. Zhuxi focused on the importance of "Great Learning 大學" as a study of the Great people and argued that "Great Learning" is the study for all the people should learn. On the other hand, Dasan claimed that "Tàixuézhīdào太學之道" in "Great Learning" is the study for the prince, not for the normal people. And he also interpreted "Dàxué 大學" as the school for teaching prince. In addition, "Great Learning" suggested the three practical principles; to illustrate illustrious virtue; to renovate the people; and to rest in the highest excellence. However, Dasan argued different way and emphasized three ethics of practice; filial piety(孝), admiration(弟), mercy(慈) and regarded as illustrious virtue of "Great Learning." He denied the three principle of "Great Learning" that Zhuxi reorganized and suggested including renovating the people(新民), and provided that close to the people(親民) is one of the main principles of "Great Learning." According to Dasan, if the king practices these three ethics of practice including filial piety, admiration, and mercy, so that the people will practice these ethics voluntarily. In other words, he indicated that the practice of three ethics is not only for the prince in the loyal family, but also for principles to educate the people in the nation. Thus, three ethics by Dasan including filial piety, admiration, and mercy could be recognized as the symbol of humanity. In other words, Dasan's three ethics in "Great Learning" can be recognized as the practical principles including educational issues and educational interactions. If these three ethics can be referred as the symbol of humanity as mentioned above, the implicit educational interactions are specifically constructed within the basic assumptions. Therefore, it is possible to clarify the specific ethics of practice by the indicating specific subjects and objects in the educational interactions between these three ethics of practice. Also, it helps more clear comprehension about the "Dàxuégōngyì大學公議, The Public debate of Great Learning", by Dasan.