• Journal of the Korea Computer Graphics Society
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• v.4 no.1
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• pp.1-10
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• 1998

The idea of level-of-detail based on multiresolution model is gaining popularity as a natural means of handling the complexity regarding the realtime rendering of virtual environments. To generate an effective multiresolution model, we should capture the prominent visual features in the process of simplifying original complex model. In this paper, we incorporate view dependent features such as silhouette features and backface features, to the generation process of multiresolution model. To capture the view directional parameter, we propose multiresolution view sphere. View sphere maps the directional relationship between object surface and the view. Using the view sphere, coherence in the directional space is mapped into spatial coherence in the view sphere. View sphere is generated in multiresolution fashion to simplify the object. To access multiresolution view sphere efficiently, we devise quad tree for the view sphere. We also devise a mechanism for realtime simplification process using proposed view sphere. Using proposed mechanism, regenerating simplified model in realtime is effectively done in the order of number of rendered vertices.

• Journal of the Korean Society for information Management
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• v.24 no.3
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• pp.119-147
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• 2007

Actually a diffusion of a semantic web application and utilization are situations insufficient extremely. Technology most important in semantic web application is construction of the ontology which contents itself with characteristics of semantic web. Proposed a suitable a method of building web ontology for characteristics or semantic web and web ontology as we compared the existing ontology construction ana ontology construction techniques proposed for web ontology construction, and we analyzed. And modeling old ontology to bases to description logic and the any axiom rule that used an expression way of SWRL, and established inference-based web ontology according to proposed ways. Verified performance of ontology established through ontology inference experiment. Also established an web ontology-based intelligence image retrieval system, to experiment systems for performance evaluation of established web ontology, and present an example of implementation of a semantic web application and utilization. Demonstrated excellence of a semantic web application to be based on ontology through inference experiment of an experiment system.

• Journal of the Korean Society for information Management
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• v.26 no.3
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• pp.451-462
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• 2009

The aim of this study is to apply latent semantic indexing(LSI) techniques for efficient automatic classification of opinionated documents. For the experiments, we collected 1,000 opinionated documents such as reviews and news, with 500 among them labelled as positive documents and the remaining 500 as negative. In this study, sets of content words and sentiment words were extracted using a POS tagger in order to identify the optimal feature set in opinion classification. Findings addressed that it was more effective to employ LSI techniques than using a term indexing method in sentiment classification. The best performance was achieved by a supervised LSI technique.

• Journal of the Korean Society for information Management
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• v.24 no.2
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• pp.71-87
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• 2007

With the rapid change of the Web and E-transaction application, the search interface is providing more powerful search and visualization methods, while offering smoother integration of technology with task. Especially, visualization techniques for long menu-lists are applied in retrieval system with the goal of improving performance in user's ability to select one item from a long list. In order to review visualization techniques appropriate to the types of users and data set, this study compared the five visualization browsers such as the Tree-structured menu, the Table-of-contents menu, the Roll-over menu, the Click menu, and Fisheye menu. The result of general analyses shows that among the hierarchical methods, the experienced group prefers the Table-of-contents method menu, whereas the novice's group prefers the Tree-structure method menu. Among the linear methods, the two groups prefer the Roll-over menu. The Roll-over menu is most preferred among the five browsers by the two groups.

• Journal of KIISE:Software and Applications
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• v.35 no.12
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• pp.741-752
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• 2008

Aspect-Oriented Software Development(AOSD) is the software development methodology that classifies concerns of the system and identifies crosscutting concerns and organizes aspect class, and AOSD has emerged as an important user-oriented software development methodology with high maintainability. However, most of related studies worked on identification and specification and coding of crosscutting concerns. And there have been few studies on slicing technique for tracing method of specified crosscutting concerns. Therefore, this paper proposes slicing technique based on AOSD that identifies and specifies crosscutting concerns through interactive analysis between use cases; also, suggests slicing technique which improves traceability centering on identified crosscutting concerns; applies the aspect-oriented slicing technique to Learning Management System(LMS) for case-study. LMS is a cyber educational system that demands a lot of functional changes and expansion, so it is effective to apply AOSD with high maintainability in developing LMS; and shows the results that compared with related studies by comparing six elements.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.5
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• pp.130-138
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• 2009

6LoWPAN is IPv6 packets transmission technology at Sensor network over the IEEE 802.15.4 Standard MAC and Physical layer. Adaptation layer between IP layer and MAC layer performs fragmentation and reassembly of packet for transmit IPv6 packets. RFC4944, IETF 6LoWPAN WG standard document define packet fragmentation and reassembly. In this paper, we propose the IRM(Immediate Retransmission Method) and SRM(Selective Retransmission Method) to manage packet fragmentation and reassembly at 6LoWPAN. Each time destination receives a fragmented packet, it sends Ack message to the source node on IRM. However, on SRM, the destination node receives all fragmented packet, it sends Ack message or Nak message to the source node. In this case, Nak message include the dropped packet number. To compare the performance of the proposed schemes, we develop a simulator using C++. The result of simulation shows the proposed schemes provider better performance than RFC4944 standard scheme.

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.4
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• pp.27-36
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• 2018

Although the current evaluation system has been revised four times since it was revised in 1996, it is insufficient to utilize it as a basis for predicting the performance degradation from the long-term viewpoint and prioritization decision for the budget input due to the evaluation system limited to securing the structural safety. Therefore, this study proposes a new evaluation system suitable for the performance evaluation of conventional (ASSM) tunnels among the various types of existing road tunnels using Delphi technique and AHP technique. Since the existing evaluation systems and evaluation items in domestic and overseas are limited in scope of evaluation criteria, the survey was conducted in conjunction with closed questionnaires on existing items and open questionnaires for eliciting new items. The validity of the questionnaire results were verified and the performance evaluation factors suitable for conventional (ASSM) tunnels were derived. After calculating weighted value of the derived evaluation item using AHP technique, a new evaluation system is proposed to meet the characteristics of the ASSM tunnel, so that they can be used as reference materials for revising and supplementing detailed guidelines of performance evaluation in the future.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.3
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• pp.1-7
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• 2009

At a Internet service provider(ISP), field human resources visit many customers sites to provide multimedia services to customers in ubiquitous environment. Scheduling the resources is a hard problem because there are many tasks which have to be done by the resources and the number of the resources is not sufficient. To tackle this problem, ISPs had used team-based scheduling system. However, this aporoach was not sufficient to reduce the number of frequent changes of arrival time and could not increase operational efficiency. We also developed an optimal resource selection algorithm based on statistical information when an operator assigns a task to the resource. After we adopted this algorithm to the real world, the resources can do more tasks in a day.

• Journal of the Korean Society for Library and Information Science
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• v.36 no.4
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• pp.293-309
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• 2002

This study explores what kinds of strategies are appropriate or needed for the academic librarians to upgrade their skills in the digital age. Printed and electronic sources related to this topic are gathered and examined, and communication with some academic librarians in USA is used for this study. The skills suggested in this paper mostly come from business-oriented concepts ike Learning Organization, Knowledge Management, Team Management, Customer-Oriented Services, and Change Management. As a result of this study, it is found that these skills can be used without much difficulties in academic libraries to improve their services. However academic librarians need to keep in mind the core values of academic libraries as an academic forum and non-profit organization when they endeavor to provide better services for customers in the digital age.

• Journal of KIISE
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• v.42 no.5
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• pp.566-572
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• 2015

We proposed a novel energy optimization technique for smartphone GPUs, more aggressively lowering the GPU frequency while obtaining higher energy efficiency with a negligible negative impact on the GPU performance. In order to achieve the Quality of Service (QoS) specified by the smartphone application, the proposed optimization technique employed the minimal acceptable GPU frequency based on average Frames per Second (FPS) for each GPU frequency level. Our experimental results on a smartphone development board showed that the proposed technique can reduce the GPU energy consumption by up to 23% over the default DVFS algorithm with only a 0.45 frame drop.