• Proceedings of the Korean Magnetic Resonance Society Conference
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• 2002.08a
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• pp.80-80
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• 2002

MnPSO-34 and Mn-impregnated SAPO-34 (Mn-SAPO-34) sample were prepared with various manganese contents and studied by electron spin resonance (ESR) and electron spin-echo modulation (ESEM). Electron spin-echo modulation analysis of 0.07mol ％ Mn(relative to p) in MnAPSO-34 with adsorbed D$_2$O shows two deuteriums at 0.25 nm and two at 0.36 nm from Mn. This suggests that two waters hydrate an MnO4 configuration with a D-O bond orientation for the waters as expect for a negatively charged site at low manganese content (0.07 mol％), the ESR spectra of MnAPSO-34 and MnH-SAPO-34 exhibit the same parameters (g 2.02 and A 87 G), but the spectra obtained from MnAPSO-34 samples are better resolved. TGA of as-synthesized MnAPSO-34 shows that the decomposition temperature in the range 200-$600^{\circ}C$ of the morpholine is 12$^{\circ}C$ higher than that in as-synthesized MnH-SAPO-34. Infrared spectra shows that the position of a band at about 15 cm-1 toward higher energy in MnAPSO-34 versus MnH-SAPO-34. The modulation depth of the two-pulse ESE of MnAPSO-34 with absorbed D$_2$O is deeper than that of MnH-SAPO-34 with absorbed D$_2$O. Three-pulse ESEM of MnAPSO-34 and MnH-SAPO-34 with absorbed deuterium oxide shows that the local environments of manganese in the hydrated samples are different, suggesting that Mn(II) is framework substituted in MnAPSO-34 since it obviously occupies an extra-framework position in MnH-SAPO-34

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.10
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• pp.2218-2226
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• 2009

TDMA based MAC protocol supporting wireless mesh network has many advantage rather than 802.11 DCF/EDCA protocol based on packet. But TDMA based MAC protocol require new synchronization method because of mobile point oscillator's difference, and distributed environments. This thesis propose synchronization method for TDMA based MAC protocol. It divides MP(Mobile Points) states into 4 types. If MP is in sync mode, it schedules TDMA local start time in time skew interval using beacon. It proposes compensation algorithms to compensate time skew caused by clock drift. This proposal show that general time error and clock drift rate value reduced and get synchronized result.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.8
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• pp.1861-1867
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• 2010

A datawarehouse is generally used in organizations for decision and policy making. And In a distribute environment when a new system is added, there needs considerable amount of time and cost due to the difference between the systems. Therefore, to solve this matter. Firstly, heterogeneous data structures can be handled by creating abstract queries according to the standard schema and by separating the queries using XMDR. Secondly, metadata dictionary which defines synonyms of metadata and methods for data expression is used to overcome difference of definition and expression of data. Especially, work presented in this thesis provides standardized information for data integration and minimizing the effects of integration on local systems in discrete environments using XMDR to create information of data warehouse in realtime.

• Journal of KIISE:Databases
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• v.31 no.3
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• pp.274-286
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• 2004

In mobile client-server environments, mobile clients usually are disconnected with their server because of high cost of wireless communication and keep their own local copies to provide efficient updating the cached map. The update of the server database leads to invalidation of the cached map in the client side. To solve the issues of invalidation of the cached map, it is not efficient to resend part of the updated server database to clients whenever the updating of the server database occurs. This paper proposes a log-based update propagation method to propagate the server's update into its relevant clients by using only update logs. Too many logs increasingly accumulate as the sever database is updated several times. The sequential search of the relevant log data for a specific client is time-consuming. Sending of unnecessary logs should be avoided for reducing the overhead of communication.'re solve these problems, we first define unnecessary logs and then suggest log reduction methods to avoid or cancel creating unnecessary logs. The update log index is used for quickly retrieving relevant logs.

• The Transactions of the Korea Information Processing Society
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• v.6 no.7
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• pp.1841-1848
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• 1999

DELVAUX is a genetics-based inductive learning system that learns a rule-set, which consists of Bayesian classification rules, from sets of examples for classification tasks. One problem that DELVAUX faces in the rule-set learning process is that, occasionally, the learning process ends with a local optimum without finding the best rule-set. Another problem is that, occasionally, the learning process ends with a rule-set that performs well for the training examples but not for the unknown testing examples. This paper describes efforts to alleviate these two problems centering on the N-version learning approach, in which multiple rule-sets are learning and a classification system is constructed with those learned rule-sets to improve the overall performance of a classification system. For the implementation of the N-version learning approach, we propose a decision-making scheme that can draw a decision using multiple rule-sets and a genetic algorithm approach to find a good combination of rule-sets from a set of learned rule-sets. We also present empirical results that evaluate the effect of the N-version learning approach in the DELVAUX learning environment.

• Hwankyungkyoyuk
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• v.20 no.2
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• pp.54-66
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• 2007

The purpose of this study is to find identity of the elementary environmental education and inquire elements of professionalism in environmental education that elementary teachers should have. This study performed a half-structured interview in twice to the eight of elementary teachers who completed the environmental education curriculum course in a graduate school or participated in the teacher training program before. As a result, this study found that the identity of the elementary environmental education consists of the unification comprehending various subjects, the well-rounded sensitivity balancing intellectual, emotional and behavioral aspects, and the grounding in forming environmentally friendly living-habit and academic basis of environments. Moreover, this study found that the teacher training program for the specialty of the elementary environmental teachers should comprise of the following twelve components: the knowledge of overall environmental curriculum, environmental life guidance and environmental classroom management, environmental teaching skills and function, the passion and commitment about environmental education, environmental sensitivity, understanding of education studies, the values and attitude about environment, environmental behavior, understanding the relationship between environmental psychology and developing stage of child, the general education and communication/cooperation with colleagues or local community, understanding of the role as an teacher for the elementary environmental education. More importantly, it would be very crucial that the teachers themselves who are the main body of education system should recognize the their role as the professionals in order to improve the quality of education.

• Journal of Korean Society of Transportation
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• v.24 no.5 s.91
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• pp.19-33
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• 2006

This paper presents the results of an experimental study on the application of NTCIP protocol to Korean traffic signal control system. For this study the communication Protocol of the existing traffic signal control system was adjusted to meet NTCIP standard. Management information base for Korea real-time traffic signal control system, message library of OER, traffic control center management software supporting SNMP/SFMP Protocol, and agent softwares for local controllers were developed during the experimental study. The applicability test of the adjusted system by NTCIP standard was performed. Fifty eight Percent of communication packets were lost at 2.400bps communication speed, which made the operation impossible. The experimentations with communication speeds 4,800bps and 9,600bps did not cause problems. In conclusion, to apply the NTCIP standard to domestic real-time traffic control system, communication environments need to be upgraded to 4,800bps or higher.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.26 no.1
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• pp.9-16
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• 2008

Korea's GIS market has been proliferating since the 1990s, but still its scale and the structure require overall rearrangements. Recently as the needs and initiatives from central and local governments go stronger to drive 'u-City(ubiquitous City)' developments, there are much more demand of spatial information from sectors like city management, construction, environment and so on. Through the merge between GIS and the advanced Information and Telecommunication Technology, the introduction of new Ubiquitous IT is swiftly changing GIS market environments, so the GIS industry is to be prepared for this trend. The pioneering developments of Ubiquitous-related GIS technologies are expected to highly boost spatial data and related industries, and the pre-occupancy of those technologies in the world would enable the expansion of overseas export market. In the context of these epoch-making chances, by looking into the actual status of GIS industry, this study is to investigate the actual accomplishments to foster the GIS industry through Korea's National GIS Master Plan. Thereby, impending issues will be discussed to provide useful problem-solving suggestions.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.35 no.3
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• pp.167-174
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• 2017

Antarctica, where ice sheet has been declined rapidly, should be monitored periodically. However, there are difficult to access for local survey or aircraft observation due to the vast and extreme environments of the polar regions. In order to overcome this problem, there have been a lot of studies by acquiring radar or laser data by satellite. It is also difficult to accurately measure the changes of the surface where is composed of snow or ice layer, and it is also difficult to product a high-resolution DEM. This study therefore aims to product DEMs of two periods using high-resolution KOMPSAT-3A stereo images, and DEM matching is implemented by the LZD(Least-squares Z-Differences) method to detect DEM changes in both periods. As a result, the proposed method could be suggested as comparing height differences of the two DEMs within 1m precision.

• Journal of KIISE:Information Networking
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• v.36 no.4
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• pp.263-274
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• 2009

Decentralized group key management mechanisms offer beneficial solutions to enhance the scalability and reliability of a secure multicast framework by confining the impact of a membership change in a local area. However, many of the previous decentralized solutions reveal the plaintext to the intermediate relaying proxies, or require the key distribution center to coordinate secure group communications between subgroups. In this study, we propose a decentralized group key management scheme that features a mechanism allowing a service provider to deliver the group key to valid members in a distributed manner using the proxy cryptography. In the proposed scheme, the key distribution center is eliminated while data confidentiality of the transmitted message is provided during the message delivery process. The proposed scheme can support a secure group communication in dynamic network environments where there is no trusted central controller for the whole network and the network topology changes frequently.