• The KIPS Transactions:PartD
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• v.8D no.6
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• pp.853-860
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• 2001

In the object-oriented software development, redesigning of classes and reorganizing of class hierarchy structures should be necessary to reduce many of the headaches of object-oriented software design and maintenance. To support this task, in this paper, we propose a theoretical foundation for class hierarchy reorganizations that is relatively complete, correct, formal and easy to understand and use. We introduce the flattened class hierarchy that characterizes the class hierarchy structures in object-oriented software evolution. And we also present an algorithm which transforms a given class hierarchy into the normalized form. The flattened class hierarchy helps us map the inheritance and aggregation paths in a class hierarchy to paths in an object hierarchy that is an instance of the class hierarchy. By applying the algorithm into a given class hierarchy, we can make a new, object-preserved, and flattened class hierarchy that is the cornerstone for reorganization of class hierarchy structure and plays an important role as a bridge on the incremental evolutionary changes and reuse of object-oriented software to reorganize class hierarchies.

• Journal of Internet Computing and Services
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• v.19 no.5
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• pp.107-113
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• 2018

Object-oriented databases (OODBs) canbe used for many non-traditional database application areas such as computer-aided design, etc. Usually those application areas require advanced modeling power for expressing complicated relationships among data sets. OODBs have more distinguished features than the traditional relational database systems. One of the distinguished characteristics of OODBs is class hierarchy (also called inheritance hierarchy). A class hierarchy in an OODB means that a class can hand down the definitions of the class to the subclass of the class. In other words, a class is allowed to inherit the definitions of the class from the superclass. In this paper, we present performance evaluation metrics for class hierarchy in OODBs from a concurrency control perspective. The proposed performance metrics are developed to determine which concurrency control scheme in OODBs can be used for a given class hierarchy. In this study, in order to develop performance metrics, we use class hierarchy structure (both of single inheritance and multiple inheritance), and data access frequency for each class. The proposed performance metrics will be also used to compare performance evaluation for various concurrency control techniques.

• Journal of Korea Multimedia Society
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• v.9 no.6
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• pp.693-699
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• 2006

Object-oriented databases (OODBs) have been adopted for managing non-standard applications such as computer-aided design (CAD), office document management and many multimedia applications. One of the major characteristics of OODBs is class hierarchy where a subclass is allowed to inherit the definitions defined on its superclasses. In this paper, I present the evaluation metrics for class hierarchy quality in OODBs. These metrics are developed to determine if a concurrency control scheme can achieve good performance or not on a given class hierarchy. I first discuss the existing concurrency control schemes for OODBs. Then I provide evaluation metrics based on structural information and access frequency information in class hierarchies. In order to discuss significance of the proposed performance metrics, an analytical model is developed. Analysis results show that the performance metrics are important factor in concurrency control performance. I consider both single inheritance and multiple inheritance. The proposed metrics can be used to provide guidelines on how to design class hierarchy of an OODB for maximizing the performance of concurrency control technique.

• The Transactions of the Korea Information Processing Society
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• v.5 no.1
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• pp.86-96
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• 1998

The class hierarchy structure in an object-oriented design model is effective to the software reusabilily and lhe design of complex syslem. This paper suggests lhe objecl-orienled class hierarchy structure design melhod using lhe rapid prololyping lechniques. In this method, relationship recognition and similarity are estimated by the new class classification in object modeling level. Then lhe estimation of aUribute and method in class is needed. Each design module such as class hierarchy struclure which is generaled wilh inleractive and repealed work consisls of reference relationship, inheritance relationship and composite relationship. These information are slored in lhe table to maintenance lhe program and implementation, the class relationship is represented with graph and the node class is iconized. This method is effective in reslructuring of class hierarchy are reusing of design information, because of addition of new class and deletion with ease. The efficiency of syslem analysis, design and implementation is enhanced by converting into prololype system and real system.

• 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.

• The KIPS Transactions:PartD
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• v.10D no.5
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• pp.859-872
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• 2003

Class hierarchies often constitute the backbone of object-oriented software. Their quality is therefore quite crucial. Building class hierarchies with good qualify is a very important and common tasks on the object oriented software development, but such hierarchies are not so easy to build. Moreover, the class hierarchy structure under construction is frequently restructured and refined until it becomes suitable for the requirement on the iterative and incremental development lifecycle. Therefore, there has been renewal of interest in all methodologies and tools to assist the object oriented developers in this task. In this paper, we define a set of quantitative metrics which provide a wav of capturing features of a rough estimation of complexity of class hierarchy structure. In addition to, we suggest a set of algorithms that transform a original class hierarchy structure into reorganized one based on the proposed metrics for class hierarchy structure. Furthermore, we also prove that each algorithm is "object-preserving". That is, we prove that the set of objects are never changed before and after applying the algorithm on a class hierarchy. The technique presented in this paper can be used as a guidelines of the construction, restructuring and refinement of class hierarchies. Moreover, the proposed set of algorithms based on metrics can be helpful for developers as an useful instrument for the object-oriented software development.velopment.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.2
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• pp.215-224
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• 1997

This paper addresses the vertical class fragmentation in distributed object-oriented databases. In the proposed vertical fragmentation, after producing the attribute fragment by partitioning attributes, then the method fragment is produced by gathering methods referring the attribute in each fragment. For partitioning attributes, we define query access matrix(QAM) and method access matrix(MAM) to express attributes that method refers, and extend QAM, MAM and attribute usage matrix(AUM) to universal class environment for representing relationship among other classes through class hierarchy and class composite hierarchy.

• Journal of Electrical Engineering and information Science
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• v.1 no.1
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• pp.164-172
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• 1996

The partitioning of related objects should be performed before clustering for an efficient access in object-oriented databases. In this paper, a horizontal partition of related objects in object-oriented databases is presented. All subclass nodes in a class inheritance hierarchy of a schema graph are shrunk to a class node in the graph that is called condensed schema graph because the aggregation hierarchy has more influence on the partition than the class inheritance hierarchy. A set function and an accessibility function are defined to find a maximal subset of related objects among the set of objects in a class. A set function maps a subset of the domain class objects to a subset of the range class objects. An accessibility function maps a subset of the objects of a class into a subset of the objects of the same class through a composition of set functions. The algorithm derived in this paper is to find the related objects of a condensed schema graph using accessibility functions and set functions. The existence of a maximal subset of the related objects in a class is proved to show the validity of the partition algorithm using the accessibility function.

• Journal of the Korean Institute of Educational Facilities
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• v.10 no.5
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• pp.35-43
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• 2003

This study analyzed the spatial hierarchy of Hyangkyo architecture. Hyangkyo was built on the basis of Confucianism. The results are as follows; 1) The spatial hierarchical construction responding to the site. The arrangement style of hierarchical construction changed according to the site. This is the reason that the hierarchy of Confucianism has the relationship of the upper class and the lower class, high and low of position, high of right and low of left, and the theory of division based on topography. 2) The hierarchical construction responding to the arrangement style. Buildings were hierarchically constructed according to the site of the architecture. This is the result of hierarchy. In conclusion, the spatial hierarchy means that Hyangkyo architecture had been built according to an order on the basis of Confucianism.

• Journal of Practical Engineering Education
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• v.14 no.3
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• pp.513-522
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• 2022

Course evaluation serves as helpful information to improve the quality of college education and improve lectures. This study derived the factors through preceding research and FGI to explore the factors that constitute course evaluation and identified the relative importance and priority of the factors through the Analytic Hierarchy Process (AHP). For this, it derived five factors and 15 evaluation items as follows. To secure expertise and fairness in the factor development of course evaluation, the researcher conducted a questionnaire surveying students and teachers and collected a total of 20 valid data. The weight of each evaluation item was calculated based on the data that had been verified for consistency. The analysis concluded that students rated class content, class method, class operation, class evaluation, and class plan as the critical factors in the order of importance, while teachers evaluated class content, class operation, class method, class evaluation, and class plan as important, in that order. Based on the results of this study, I hope that various analyses and studies will be conducted to improve the efficiency and reliability of course evaluation for the quality management of college education.