• Spatial Information Research
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• v.21 no.6
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• pp.23-32
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• 2013

Recently, there has been much interest in the converged platform that enables the harmonized collection, integration, exchange, presentation and analysis of various kinds of marine information by using the ICT means. Regarding such the converged platform, S-100 standards including the international hydrographic data model are being announced and various studies have been published based on the S-100 standards. However, the existing studies have presented simple solutions for only given problems on the converged service of the maritime information. They could not propose the design concept of the converged platform which makes it possible to provide the standardized and integrated services among the geospatial data, the real-time maritime data, and the next ENC. Therefore, we propose design and implementation details of the converged service platform for the geospatial and the maritime data based on the S-100, WMS, WMTS, WPS, SOS standards. The proposed platform has advantages of supporting both the S-57 and the S-101, supporting the converged services of heterogeneous geospatial data and ENC data, supporting the real-time services of sensor data such as weather, AIS, and CCTV, and supporting the development of various kinds of maritime systems such as ECDIS, ECS, VTS based on the WebApp service. Finally, we proved the effectiveness of our proposed platform through the actual implementation of the converged service of geospatial data, S-101 data, and KWeather data.

• Journal of KIISE
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• v.43 no.11
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• pp.1216-1222
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• 2016

The advent of large-scale web services has resulted in gradual increase in the amount of data used in those services. These big data are managed efficiently by DBMS such as MySQL and MariaDB, which use InnoDB engine as their storage engine, since InnoDB guarantees ACID and is suitable for handling large-scale data. To improve I/O performance, InnoDB caches data and index of its database through a buffer pool. It also supports multiple buffer pools to mitigate lock contentions. However, the multiple buffer pool scheme leads to the additional data consistency overhead. In this paper, we analyze the overhead of the multiple buffer pool scheme. In our experimental results, although multiple buffer pool scheme mitigates the lock contention by up to 46.3%, throughput of DMBS is significantly degraded by up to 50.6% due to increased disk I/O and fsync calls.

• Journal of KIISE:Computer Systems and Theory
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• v.34 no.9
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• pp.395-406
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• 2007

Races in programs with OpenMP directives must be detected for debugging, because they may cause unexpected result by non-deterministic executions. But, Thread Checker of Intel corporation, a well-known existing tool for detecting the races, is not practical because this tool does not verify the existence of races and is known that the cost for race detection is too big. This paper presents a web-based tool which verify the existence of races with an optimal functionality and performance using the results from the property analysis of OpenMP program as well as the user requirements. Our tool is proved to be practical in the aspect of functionality and performance by experiments using synthetic programs, because the suggested tool can verify the existence of race and shows O(n) as the ratio of time consumption while Thread Checker can not verify the existence of race and shows $O(n^2)$ as the ratio, where n is the number of total accesses.

• The KIPS Transactions:PartD
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• v.12D no.2 s.98
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• pp.199-210
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• 2005

We need XML generate various kinds of XML data to evaluate XML database systems. Existing XML data generators are developed to generate XML data that are suitable for particular evaluation methods, and their functionalities are limited in terms of generating XML data This paper introduces a new XML data generator, WeXGene, that not only improves the drawbacks of existing data generators but also adds new data generation functionalities. For generating XML data WeXGene uses the user data files and the structure definition files, which specify SDTD(Symbolic DTD) or input parameters. The user data file is a text data file that has column data or row data. It is also possible that WeXGene generates XML data without accessing the user data file. This paper presents the design details, overall system architecture, and data generation process of WeXGene. An analytic comparison with other XML data generators is also presented.

• 한국HCI학회:학술대회논문집
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• 2007.02b
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• pp.206-212
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• 2007

웹을 기반으로 하는 e-러닝에 대한 교육적 수요는 증가하고 있다. 이와 동시에, 학습 공간으로서의 사이버 공간의 활용에 대한 고민도 증가하였다. 전통적인 학습활동을 사이버 공간에 복제하려 했던 고전적 방식이 e-러닝 또는 사이버 학습이 아니라는 사실을 확인하기 시작했기 때문이다. e-러닝의 가치가 강조됨에도 불구하고, 실제 사이버 공간에서 일어나는 학습자의 특성과 학습활동이 구체적으로 어떻게 일어나는 지에 대한 탐색은 미흡하다. 산재한 정보를 스스로 가공한 지식, '학습하는 방법을 학습'하는 것이라는 개념들이 제시됨에도 불구하고, 사이버 공간에 산재한 정보, 학습하는 방법의 학습, 그리고 사이버 공간의 학습특성에 대한 논란은 여전하다. 본 연구에서는 실제 사이버 학습 사이트를 이용하고 있는 학습자들의 행동을 중심으로, 학습자의 특성을 탐색하였다. 사이버 공간에서 보이는 스스로 학습하는 방법이 무엇인지 확인하고 이것이 다양한 학습자 유형으로 구분되는 지를 확인하고자 하였다. 연구대상이 된 사이버 학습 사이트는 서울, 부산, 대구, 광주 교육청에서 운영하는 사이버 가정 학습관이었다. 총 1535명의 사이버 가정 학습관 이용자들의 특성이 분석되었다. 사이버 가정학습관 이용자들의 행동특성은 9개의 요인-놀이 활동, 공동 경험, 현실 정체, 공동 성취, 개인주의, 경쟁 지향, 성취감, 편리성(조작 용이), 생생함-으로 구분되었다. 9개의 활동 요인을 기준으로 하여 확인된 학습자 유형은 4가지로 나타났다. 4가지 학습자 유형은 각각 독야청청형, 동고동락형, 의무방어형, 희희낙낙형으로 명명되었다. 이들 유형은 학습 활동 정도 및 사이트 이용 행동, 학습 스타일(사이버 학습 활동 양식)에서 서로 차이가 있었다. 본 연구는 기존의 이론적인 모델에 기초하여 임의적으로 구분된 사이버 학습자 유형 구분이 아닌, 실제 학습 활동을 탐색하였다는 측면에서 의미가 있다. 특히, 기존의 오프라인 학습 이론 및 학습자 특성 연구를 사이버 학습에 그대로 적용할 것이 아니라 사이버 공간의 특성이 실제 학습 활동에서 어떻게 나타났는지를 밝히려고 했다는데 그 의의가 있다. 향후, 사이버 학습자 유형에 따른, 사이버 학습활동의 촉진방안이나 학습 효과의 차이를 높일 수 있는 구체적인 학습 시스템의 설계 및 운영 모델에 대한 탐색이 필요할 것이다.

• Journal of the Korean Society for Library and Information Science
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• v.35 no.4
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• pp.97-122
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• 2001

This empirical study investigated the effect of choice of record field(s) upon which to search on retrieval performance for a large operational bibliographic database. The query terms used in the study were identified algorithmically from each target set in four different ways: (1) controlled terms derived from index term frequency weights, (2) uncontrolled terms derived from index term frequency weights. (3) controlled terms derived from inverse document frequency weights, and (4) uncontrolled terms based on universe document frequency weights. Su potable choices of record field were recognised. Using INSPEC terminology, these were the fields: (1) Abstract. (2) 'Anywhere'(i.e., ail fields). (3) Descriptors. (4) Identifiers, (5) 'Subject'(i.e., 'Descriptors' plus Identifiers'). and (6) Title. The study was undertaken in an operational web-based IR environment using the INSPEC bibliographic database. The retrieval performances were evaluated using D measure (bivariate in Recall and Precision). The main findings were that: (1) there exist significant differences in search performance arising from choice of field, using 'mean performance measure' as the criterion statistic; (2) the rankings of field-choices for each of these performance measures is sensitive to the choice of query : and (3) the optimal choice of field for the D-measure is Title.

• The KIPS Transactions:PartC
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• v.11C no.7 s.96
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• pp.937-950
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• 2004

In this paper, we present the design and implementation of new execution environment named Customizable Architecture for Flexible Execution Environment(CAFEs) that supports the mechanism of protocol customization and service referencing. We introduce a new concept as micro protocols and active services to enhance software reusability. Micro protocol represents a specific algorithm or functionality of existing network protocol and the active service is in charge of binding legacy application and releasing the active network oriented services. The pro-posed active network execution environment is made up of three parts, virtual network system, protocol and service manager, event engine. First, the virtual network system is used to connect each active nodes using virtual network channels which are based on multiple existing protocol layers. Second, the protocol and service manager is responsible for composing micro protocols and active services to develop new network proto-col and service easily. Finally, the event engine is used to detect the automatic transition of system components using event delegation model. To verify the CAFTs, we have an experiment about the delivery of web contents which are suitable for the user's terminals in the wireless Internet environment. As a result. we are able to obtain the availability of developed execution environment.

• Journal of Digital Contents Society
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• v.10 no.1
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• pp.129-145
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• 2009

As the secure distribution and sharing of information over the World Wide Web becomes increasingly important, the needs for flexible and efficient support of access control systems naturally arise. Since the eXtensible Markup Language (XML) is emerging as the de-facto standard format of the Internet era for storing and exchanging information, there have been recently, many proposals to extend the XML model to incorporate security aspects. To the lesser or greater extent, however, such proposals neglect the fact that the data for XML documents will most likely reside in relational databases, and consequently do not utilize various security models proposed for and implemented in relational databases. In this paper, we take a rather different approach. We explore how to support security models for XML documents by leveraging on techniques developed for relational databases considering object perspective. More specifically, in our approach, (1) Users make XML queries against the given XML view/schema, (2) Access controls for XML data are specified in the relational database, (3) Data are stored in relational databases, (4) Security check and query evaluation are also done in relational databases, and (5) Controlling access control is executed considering XML tree levels

• Journal of The Korean Association of Information Education
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• v.17 no.4
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• pp.375-382
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• 2013

Collaborative filtering has been most widely used in commercial sites to recommend items based on the history of user preferences for items. The basic idea behind this method is to find similar users whose ratings for items are incorporated to make recommendations for new items. Hence, similarity calculation is most critical in recommendation performance. This paper presents a new similarity measure that takes each rating of a user relatively to his own ratings. Extensive experiments revealed that the proposed measure is more reliable than the classic measures in that it significantly decreases generation of extreme similarity values and its performance improves when consulting neighbors with high similarites only. In particular, the results show that the proposed measure is superior to the classic ones for datasets with large rating scales.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.7
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• pp.1740-1748
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• 2014

This paper focuses on listening test and acoustic analysis of patients' speech with velopharyngeal insufficiency (VPI) and normal speakers' simulation speech. In this research, a set consisting of 50-words, vowels and single syllables is determined for speech database construction. A web-based listening evaluation system is developed for a convenient/automated evaluation procedure. The analysis results show the trend of incorrect recognition for VPI speech and the one for simulation speech are similar. Such similarity is also confirmed by comparing the formant locations of vowel and spectrum of consonant sounds. These results show that the simulation method for VPI speech is effective at generating the speech signals similar to actual VPI patient's speech. It is expected that the simulation speech data can be effectively employed for our future work such as acoustic model adaptation.