• The KIPS Transactions:PartD
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• v.13D no.4 s.107
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• pp.477-490
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• 2006

Existing index structures need very much update cost because they repeat delete and insert operations in order to update continuously moving objects. In this paper, we propose a new index structure which reduces the update cost of continuously moving objects. The proposed index structure consists of a space partitioning index structure that stores the location of the moving objects and an auxiliary index structure that directly accesses to their current positions. In order to increase the fanout of the node, it stores not the real partitioning area but kd-tree as the information about the child node of the node. In addition, we don't traverse a whole index structure, but access the leaf nodes directly and accomplish a bottom-up update strategy for efficiently updating the positions of moving objects. We show through the various experiments that our index structure outperforms the existing index structures in terms of insertion, update and retrieval.

• Journal of the Korea Society of Computer and Information
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• v.13 no.6
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• pp.51-58
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• 2008

A version control system is used in a rapidly changed environment or a program which developed in a complicated environment. it is a problem of configuration thread in supporting information that we, in this method, can't know a exactly well-defined configuration rule information and a predefined information. In this paper. Library system is suggested, modelled, and implemented so as to configuration thread control the components required by the user in many ways. As for the library used in the configuration thread control suggested in this paper, the components can be retrieved from the library regardless of the infrastructure, applying the extended facet classification. This retrieval framework is managed using TreeSearch class and the configuration thread control function. The library system of this paper can be used by the interface with other languages, and this system is to have a advantage to extend a facet by user.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.5
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• pp.947-956
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• 2021

As an interest in metaverse increases, there are many studies to apply virtual reality to indirect experiences. Virtual reality is increasingly being used not only for entertainment such as games but also for educational content. A key technology of indirect experience is modeling an object to provide a realistic experience to the user. Natural environments such as tidal flats change with time, and many living things also live there. In this paper, we propose a method for creating experiential content that accurately models the ecological environment of tidal flats. The proposed method explains how to naturally model the temporal change of tidal flats. We also explain how to model a crab, a creature that inhabits the tidal flat, in the forms of an NPC using the behavior tree. Implementation results show that the proposed method uses simple algorithms but expresses the shapes of tidal flats well.

• The Mathematical Education
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• v.60 no.3
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• pp.249-264
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• 2021

This article is devoted to investigating young learners' understanding of elapsed time from socio-cultural perspectives. The socio-cultural perspective benefits to access and personalize mathematics learning as how to have a mathematical object to be able to realize signifiers with the help of many other mathematical words and mediators. In terms of the realization of signifiers, I analyzed performances on elapsed time tasks of students in Grades 3 (n=115) and interviewed focal students. Quantitative analysis on students' performance identified that students perform differently when the task provided with the analog clock signifier. It suggested that students might think in a different way upon the given signifier even for the same elapsed time, especially when given as the analog clock. Qualitative analysis on focal students' interviews visualized how the students' understanding were different by displaying individual realization trees on elapsed time. The particular location of the analog clock signifier on each realization tree provided a personalized explanation about low performance on the task with analog clock signifier. The finding suggested that the realization of a specific signifier could be a key point in elapsed time understanding. I discussed why a majority of students face difficulty in elapsed time learning indicated analog clock and the advantage of moving elapsed time strands to higher grades in the school mathematics curriculum.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.32 no.4
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• pp.61-72
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• 2014

Throughout analyzing and construing the words, contexts, and expressive languages used for depicting the pine tree in the novel "Honbul" written by Choi, Myung-Hee the symbolism of the pine and folksy languages used for scenery can be condensed as written below: First, it is explicit that the scenery-words for illustrating the pine tree in "Honbul" are emerged through diverse means methods and expressions. Namely, the reference forms of the pine tree and the expressive means of utilizing words portrays the use of the pine are various and subdivided. Second, the scenery-words found in vocabularies and the contexts of "Honbul" imply various symbolic representation. They not only perform to describe inherent image and symbolism of the pine, but they work for reifying the image of "Honbul" in the narrative structure in "Honbul" as being intrinsic scenery-word. Third, the scenery-words used for expressing aesthetics emerge as synesthetic expressions through the linear beauty and the texture of the pine as well as through five-senses. Forth, on the basis of the inherent symbolism and the image of the pine, the landscape of the background described in "Honbul" deems as a symbolic backdrop. As with then narrative structure of the novel, the pine tree performs as a mediation of the heaven and the earth, god and man, as well as the sacred and the secular. Fifth, scenery-words used for depicting the pine tree are a symbol that represents the spirit and emotion of the character in the novel. Moreover, it is a tool for pursuing the personification of the nature, the deification of the object, and the cosmos of the space. It is also utilized as a device that definitize the ideational image applied to express the landscape of the background of the novel. As mentioned above, the expressions, vocabularies and textures about pine tree represented from "Honbul" are expected to be the beginning of understanding the landscape-images and landscape-languages of pine in not only the setting for this novels, Namwon but also the entire districts of Korea.

• Journal of Korea Spatial Information System Society
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• v.11 no.2
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• pp.99-110
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• 2009

Currently, there are many applications being developed based on sensor network technology. A tracking method for moving objects in sensor network is one of the main issue of this field. There is a little research on this issue, but most of the existing work has two problems. The first problem is a communication overhead for visiting sensor nodes many times to track a moving object. The second problem is an disability for dealing with many moving objects at a time. To resolve the problems, we, in this paper, propose a signature-based tracking method using efficient data aggregation for moving objects, called SigMO-TRK. For this, we first design a local routing hierarchy tree to aggregate moving objects' trajectories efficiently by using a space filtering technique. Secondly, we do the tracking of all trajectories of moving objects by using signature in a efficient way, our approach generates signatures to method. In addition, by extending the SigMO-TRK, we can retrieve the similar trajectories of moving objects for given a query. Finally, by using the TOSSIM simulator, we show that our signature-based tracking method outperforms the existing tracking method in terms of energy efficiency.

• Journal of KIISE:Databases
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• v.30 no.1
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• pp.41-51
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• 2003

The spatiotemporal database concerns about the time-varying spatial attributes. One of the important research areas is related to the support of various location-based services in motile communication environments. It is known that database systems may be difficult to manage the accurate geometric locations of moving objects due to their continual changes of locations. However, this requirement is necessary in various spatiotemporal applications including mobile communications, traffic control and military command and control (C2) systems. In this paper we propose the $B^{st}$-tree that utilizes the concept of multi-version B-trees. It provides an indexing method (or the historical and future range query Processing on moving object's trajectories. Also we present a dynamic version management algorithm that determines the appropriate version evolution induced by the mobility patterns to keep the query performance. With experiments we .;hi)w that our indexing approach is a viable alternative in this area.

• Journal of KIISE:Software and Applications
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• v.26 no.9
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• pp.1039-1051
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• 1999

시공간 데이타베이스는 현실세계의 객체에 대하여 효율적인 공간 관리와 이력 관리를 지원한다. 이러한 시공간 데이타베이스는 시간차원과 공간차원이라는 이질적 데이타 공간을 관리하여야 하는 대단히 복잡한 시스템이다. 따라서 데이타에 대한 효율적 접근 방법에 대한 연구가 필수적이며, 이는 효율적 색인 기법의 개발을 통하여 이룰 수 있다. 그러나 시공간 데이타에 대한 접근방법 연구는 거의 이루어지지 않고 있으며 극소수의 사례들마저도 공간 객체의 이력 개념을 지원하는 것이 아니라 멀티미디어 객체의 상대적 시간만을 지원하고 있다. 따라서 이 논문에서는 공간 데이타의 이력을 표현하는 시공간 데이타에 대하여 효율적으로 색인하기 위한 방안으로서 시간과 공간을 단일화된 색인 영역으로 통합하는 단일화된 시공간 색인 모델을 제시하고, 이를 기존의 R-트리를 기반으로 확장한 색인을 설계 및 구현하였으며, 아울러 다양한 유형의 시공간 연산에 대한 색인의 성능을 평가하였다.Abstract Spatiotemporal databases are able to support an efficient spatial management as well as historical management for an object in the real world. It is very complex to manage these two dimensions why there exists on difference of inborn property of temporal and spatial dimensions. Therefore an efficient access method should be studied, and it can be done by means of development of efficient indexing technology.However, there is a few related work in the research of access methods of spatiotemporal data. Also the previous works do not support the concept of history for spatial object, and only support the relative time among multimedia objects. Therefore, in this paper, we propose a unified Spatiotemporal index model as an efficient index for Spatiotemporal data. And we not only design Spatiotemporal index that has been extended to historical management facility on the basis of conventional R-tree, but also implement it. Finally we have evaluated performance of index for the various kinds of Spatiotemporal operations.

• The Transactions of the Korea Information Processing Society
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• v.7 no.4
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• pp.1033-1043
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• 2000

Recently as the user request on NoD (News-on-Demand) is largely increasing, there are a lot of researches to fulfill it. However, because of short life-cycle of new video data and periodical change of video data depending on anchor, it is difficult to apply the conventional video storage techniques to NOD applications directly. For this, we design and implement low-level storage manager for efficient storage and retrieval of multimedia data in NOD Services. Our low-level storage manager not only efficiently sotres video stream dat of new video itself, but also handles its index information. It provides an inverted file method for efficient text-based retrieval and an X-tree index structure for high-dimensional feature vectors. In addition, our low-level storage manager provides some application program interfaces (APIs) for storing video objects itself and index information extracted from hierarchial new video and some APIs for retrieving video objects easily by using cursors. Finally, we implement our low-level storage manager based on SHORE (Scalable Heterogeneous Object REpository) storage system by sunig a standard C++ language under UNIX operating system.

• Journal of KIISE:Software and Applications
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• v.32 no.10
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• pp.984-989
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• 2005

This study aims to identify grammatical relations (GRs) in Korean sentences. The key task is to find the GRs in sentences in terms of such GR categories as subject, object, and adverbial. To overcome this problem, we are fared with the many ambiguities. We propose a statistical model, which resolves the grammatical relational ambiguity first, and then finds correct noun phrases (NPs) arguments of given verb phrases (VP) by using the probabilities of the GRs given NPs and VPs in sentences. The proposed model uses the characteristics of the Korean language such as distance, no-crossing and case property. We attempt to estimate the probabilities of GR given an NP and a VP with Support Vector Machines (SVM) classifiers. Through an experiment with a tree and GR tagged corpus for training the model, we achieved an overall accuracy of $84.8\%,\;94.1\%,\;and\;84.8\%$ in identifying subject, object, and adverbial relations in sentences, respectively.