• Journal of KIISE:Software and Applications
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• v.29 no.5
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• pp.289-294
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• 2002

It is known that restructuring feed-forward neural network affects generalization capability and efficiency of the network. In this paper, we introduce a new approach to restructure a neural network using abstraction of the hidden knowledge that the network has teamed. This method involves extracting local rules from non-input nodes and aggregation of the rules into global rule base. The extracted local rules are used for pruning unnecessary connections of local nodes and the aggregation eliminates any possible redundancies arid inconsistencies among local rule-based structures. Final network is generated by the global rule-based structure. Complexity of the final network is much reduced, compared to a fully-connected neural network and generalization capability is improved. Empirical results are also shown.

• Journal of the Korea institute for structural maintenance and inspection
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• v.4 no.2
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• pp.185-191
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• 2000

The safety problem of aged tunnels has been emphasized. For the effective maintenance, site inspection of tunnel structures and surrounding grounds are required periodically. Also, the determination of safety of tunnels is not a simple problem. So the role experienced engineer in the maintenance is very important and development of an expert system that can perform as the engineers, has been needed. In this study, from the results of numerical analysis in several case, new precision inspection rules which can substitute actual numerical analysis are determined by a commercial program FLAC and regression analysis under various parameters such as material property, lining thickness, overburden and laterial coefficients. They are added to the knowledge base to determine safety of tunnel lining. To verify the expert system, the results are compared with an existing tunnel diagnosis report. It can be concluded that the new rule are well represented the actual numerical analysis under various site conditions. Therefore it is expected that the systematic management for effective maintenance of tunnel structure will be possible.

• Journal of the Korea institute for structural maintenance and inspection
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• v.4 no.2
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• pp.175-184
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• 2000

The maintenance of tunnels is often neglected since tunnels has tendency to become stable with time. The determination of safety of tunnels is a complicated problem. So the role of experienced engineer in the maintenance is very important and development of an expert system which can perform as these engineers has been needed. In this study, an expert system which can determine the safety of tunnels is developed. The developed knowledge base contains the maintenance procedure which is used in KlSTEC(Korea Infrastructure Safety & Technology Corporation). Field test, laboratory test and nondestructive test methods are considered in this knowledge base. Criteria for each item and integrated diagnosis criteria are implemented in the expert system based on literatures and reports. The expert system includes basic inspection. detail inspection and precision inspection. For precision inspection. it has the capacity to exchange the result from numerical analysis by a commercial program FLAC. To verify the expert system. the proposed procedure was compared with an existing tunnel diagnosis report.

• Journal of Information Science Theory and Practice
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• v.8 no.4
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• pp.67-86
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• 2020

Information need has been one of the main motivations for a person using a search engine. Queries can represent very different information needs. Ironically, a query can be a poor representation of the information need because the user can find it difficult to express the information need. Query Expansion (QE) is being popularly used to address this limitation. While QE can be considered as a language-independent technique, recent findings have shown that in certain cases, language plays an important role. Arabic is a language with a particularly large vocabulary rich in words with synonymous shades of meaning and has high morphological complexity. This paper, therefore, provides a review on QE for Arabic information retrieval, the intention being to identify the recent state-of-the-art of this burgeoning area. In this review, we primarily discuss statistical QE approaches that include document analysis, search, browse log analyses, and web knowledge analyses, in addition to the semantic QE approaches, which use semantic knowledge structures to extract meaningful word relationships. Finally, our conclusion is that QE regarding the Arabic language is subjected to additional investigation and research due to the intricate nature of this language.

• Journal of The Geomorphological Association of Korea
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• v.17 no.2
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• pp.15-28
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• 2010

This study aims at the exploration of usefulness of traditional knowledge reflected in the place names. This study is useful and pragmatic for the establishment of disaster prevention measures from the analyses of disaster database, which shows the regional distribution and historical changes of disaster characteristics through history. The construction and categorization of disaster-related place names are based on historical maps and literatures on place names. One hundred twenty eight disaster-related place terminologies are selected based on disaster causes and possibilities. Design of field structures and category codes for the disaster-related place names has been proposed and the construction of disaster-related place names from the six sources has been completed.

• Journal of The Korean Association For Science Education
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• v.21 no.2
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• pp.342-356
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• 2001

Integrated science for high school is required in the present Korean National Sixth Curriculum and the Seventh Curriculum which will be effective in 2002. Currently, most science teachers in secondary school have concerns about teaching integrated science subjects and this continues to raise a significant problem for practical implementation of integrated science education in schools. In this paper, we discuss two reasons for these concerns that our analysis revealed: 1) Science teachers do not understand how to implement integrated science education and 2) there are insufficient teaching-learning materials supporting integrated science. Three different approaches to integration that have been suggested to overcome the problem of implementation are outlined here. They are the knowledge centered, social problem centered, and individual interest centered approaches. Reported here are the first two steps we undertook in preparation for testing the relative effectiveness of these approaches. First, we analyzed the content of the Korean Sixth and Seventh National Science Curricula, seven Korean integrated science text books, the American National Science Education Standards, and the American Association for the Advancement of Science Benchmarks looking for common themes. We identified in the analyzed materials the common themes: energy conservation, energy transformation, energy transport, energy degradation. We then used their energy related content to organize sets of concept structures, one set for each of the three approaches. These concept structures will provide the foundations for the development of integrated teaching-learning energy plans to be used in our research into the effectiveness of the approaches.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.23 no.2
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• pp.152-159
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• 2013

A structural health monitoring(SHM) technique for locating impact position in a composite plate is presented in this paper. The technique employs a single sensor and spatial focusing properties of time reversal(TR) and inverse filtering(IF). We first examine the focusing effect of back-propagated signal at the impact position and its surroundings through simulation. Impact experiments are then carried out and the localization images are found using the TR and IF signal processing, respectively. Both techniques provide accurate impact location results. Compared to existing techniques for locating impact or acoustic emission source, the proposed methods have the benefits of using a single sensor and not requiring knowledge of material properties and geometry of structures. Furthermore, it does not depend on a particular mode of dispersive Lamb waves that is frequently used in the SHM of plate-like structures.

• English Language & Literature Teaching
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• no.1
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• pp.69-108
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• 1995

Listening comprehension can be defined as a process of an integrative, positive and creative activity through which listeners get the message of speakers' production using linguistic or non-linguistic redundancy as well as linguistic or non-linguistic knowledge. Compared with reading comprehension, it has many difficulties especially for foreigners. while it can be transferred to the other skills: speaking, reading, writing. With this said, listening comprehension can be taught effectively using the following teaching strategies. First. systematic and intensive instruction of segmental phonemes, suprasegmental phonemes and sound changes must be given to remove the difficulties of listening comprehension concerned with the identification of sounds. Second, vocabulary drill through various games and other activities is absolutely needed until words can be unconsciously recognized. Without this, comprehension is almost impossible. Third, instruction of sentence structures is thought to be essential considering grammar is supplementary to listening comprehension and reading comprehension for academic purpose. So grammar translation drills, mechanical drills, meaningful drills and communicative drills should be performed in succession with common or frequently used structures. Fourth, listening activities for overall comprehension should teach how to receive overall meaning of intended messages intact. Linguists and literatures have listed some specific activities as follows: Total Physical Response, dictation, role playing, singing songs, selective listening, picture recognition, list activities, completion, prediction, true or false choice, multiple choice, seeking of specific information, summarizing, problem-solving and decision-making, recognization of relationships between speakers, recognition of mood, attitude and behavior of speakers.

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.11a
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• pp.33.1-33.1
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• 2009

To date, nanostructured tungsten oxides with a variety of stoichiometries, such as WO3, WO2.9, W18O49, and WO2, have been prepared, because they are promising candidates for applications such as gas sensors, photocatalysts, electrochromic devices, and field emission devices. Among them, W18O49 and WO2 have been widely studied due to their outstanding chemical sensing, catalytic, and electron emissive properties. Here we report, for the first time, a one-pot solution-phase route to synthesizing a novel composite hierarchical hollow structure without adding catalysts, surfactants, or templates. The products, consisting of a WO2 hollow core sphere surrounded by a W18O49 nanorod shell (yielding a sea urchin-like structure), were generated as discrete structures via Ostwald ripening. To our knowledge, this type of composite hierarchical core/shell structure has not been reported previously. The morphological evolution and the detailed growth mechanism were carefully studied. We also demonstrate that the size of the hollow urchins is readily tunable by controlling the reactant concentrations.Interestingly, although bulk tungsten oxides are weakly paramagnetic or diamagnetic, the as-prepared products show unusual ferromagnetic behavior atroom temperature. The urchin structures also show a very high Brunauer-Emmet-Teller (BET) surface area, suggesting that they may potentially be applied to chemical sensor or effective catalyst technologies.

• Journal of Digital Contents Society
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• v.11 no.2
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• pp.161-168
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• 2010

In the past, Korean English language learners focused on knowledge of grammatical structures. Thus Korean trained instructors, who focused on explaining the grammar structures, were seen as being preferable for teaching in EFL (English as a foreign language) classrooms. However, with the focus changed to speaking capability Koreans now desire 'fluent' English more than 'accuracy' seeing if possible (Mottos, 1997). Current study has been concerned about the issue of how non-native learners of English perceive the difference between native teachers (NTs) and non-native teachers (non-NTs) of English in the context of ELT classroom. The study explores the issues and problems the followed and how non-NTs can enhance teaching practice of speaking and listening lessons through multimedia application.