• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.7
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• pp.1639-1649
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• 1998

For mobile multimedia services, wireless ATM(Asynchronous transfer Mode) network is studied actively. In wireless ATM network, the existing signaling protocols generate heavy traffics for HLR due to the centralized structure that all signaling loads mush be handled in HLR(Home Location Register). Also, centralized structure causes critical connection setup delays. Thus, it is important that wireless ATM reduces the connection setup delays occurred due to high traffic loads of signaling based on distributed processing. In this thesis, we propose a cache strategy for call delivery as well as the cache updates of registration based on ATM multicasting and compares the cost of cache scheme with that of conventional scheme. Our study shows that cache scheme has better performance than the conventional methods in the case that the portable mobility is low and traffic density is large.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.10B
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• pp.981-987
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• 2009

Recently, the study on wireless body area network for providing ubiquitous healthcare services has been actively done, including the standardization of the IEEE and others. Wireless body area network is usually configured in tree format using multi-hop communication mode due to the power limitation and the characteristics of human body. In this case, differently from existing sensor network, the wireless body area network tends to be disconnected due to the frequent movement of human body. The number of connections which can be supported at each node has some limitations due to the constraint imposed on power consumption. In this paper, we have proposed a heuristic algorithm for optimal selection of parent node with guaranteed QoS for a disconnected node, which considers the priority on packet transmission. Simulation has been performed to evaluate the performance of the proposed algorithm.

• Spatial Information Research
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• v.12 no.4 s.31
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• pp.307-319
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• 2004

Managing GML data in traditional database systems is not efficient since It has not only characteristics of spatial data but also features of (semi) structured n documents. XML enabled database systems can manage U data efficiently, however they cannot handle spatial data. Spatial database systems are good at spatial data handling but those are inefficient for XML data. This paper proposes a storage method of GML data for spatial database systems in order to solve the problems. The proposed method generates spatial database schemas from GML application schemas and store GML data into SDBMS through the generated schemas. A prototype of the storage method has been implemented on the Postgre SQ/SPE system to show the proposed method is appropriate for storing GML data. As a result, the implemented system was able to store various GML data which had diverse XML structures and different size. Stored data size was smaller than GML files. Furthermore, spatial, non-spatial, and mixed content queries could be performed over the stored GML data as quickly.

• Journal of Digital Convergence
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• v.14 no.11
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• pp.181-191
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• 2016

The purpose of this study is to analyze the management performance of the companies in the auto parts production requirements of new management techniques ISO9001 quality management system requirements for management innovation perspective in convergence age. For this purpose, we conducted a survey visiting the auto parts manufacturers. The results were as follows. First, among the details of the four key requirements of the ISO 9001 quality management systems in small and medium component suppliers, managers and responsible resource management showed a positive impact on business performance. In addition, based on the results of the investigation of the differences by grade, the higher rank group executive responsibilities, sub-grade group showed a low awareness of the quality management according to ISO 9001. This will contribute to establishing the guidelines and Improvement Consulting Strategies to improve productivity in small and medium automotive rubber bellows automotive parts production.

• Informatization Policy
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• v.23 no.1
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• pp.3-19
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• 2016

The purpose of the study is to analyze the existing literature and to suggest future research directions in the big data security area. This study identifies 62 research articles and analyses their publication year, publication media, general research approach, specific research method, and research topic. According to the results of the analyses, big data security research is at its intial stage in which non-empirical studies and research dealing with technical issues are dominant. From the research topic perspective, the area demonstrates the signs of initial research stage in which proportion of the macro studies dealing with overall issues is far higher than the micro ones covering specific implementation methods and sectoral issues. A few promising topics for future research include overarching framework on big data security, big data security methods for different industries, and government policies on big data security. Currently, the big data security area does not have sufficient research results. In the future, studies covering various topics in big data security from multiple perspectives are anticipated.

• Journal of the Korea Society of Computer and Information
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• v.13 no.1
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• pp.261-272
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• 2008

The primary research objects of this study is to evaluate an importance of supplier selection factors as an index according the level of product standardization and to present the evaluation model for supplier selection. For this purpose, this study adopts the AHP method to calculate the importance of supplier selection factors. In this study 16 factors which affect on the supplier selection decision making are classified into three factors-product supply related factor, product related factor, management ability related factor. Results also indicate that standardized products are much more dealt by means of on-line compare to customized products. It means the buyer opportunities is potentially an increase in the amount of current supplier re-evaluation, which may lead to new suppliers being considered more often.

• Journal of Korean Society of Disaster and Security
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• v.13 no.3
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• pp.15-28
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• 2020

Hydrological data is very important in understanding the hydrological process and identifying its characteristics to protect human life and property from natural disasters. In particular, hydrological analysis are often performed assuming that hydrological data are stationary. However, recently climate change has raised the issue of climate stationary, and it is necessary to analyze the nonstationary of the climate. In this study, a method to analyze the stationarity of hydrological data was examined using the annual precipitation of 37 meteorological stations with long - term record data. Therefore, in this study, the stationary was determined by analyzing the persistence, trend, and stability using annual precipitation. Overall results showed that a trend was observed in 4 out of 37 stations, stable was investigated at 15 stations, and persistence was shown at 4 stations. In the stationary analysis using the annual precipitation data, 25 stations (67% of 37 stations) were nonstationary.

• Fire Science and Engineering
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• v.32 no.1
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• pp.108-115
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• 2018

The purpose of this study was to classify VR programs according to their characteristics and associations by the disaster management phase and firefighting school curriculum, and set priorities among VR fire training and training programs using AHP analysis., The relative priority is given considering its importance and urgency. As a result of the study, firefighting education and training classes showed the highest level of response. The relative priority of the subcategories was highest in the prevention stage. The simulation implementation for the evacuation experience was highest in closed spaces, such as a subway, and the simulation for the special firefighting vehicle was highest in the contrast phase. In the response phase, real fire simulation training was the highest. In the recovery phase, virtual reality training was the most effective in determining the fire situation based on the fire database.

• The Journal of Society for e-Business Studies
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• v.15 no.4
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• pp.303-317
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• 2010

In this paper, we propose a novel approach to fault prediction for real-time business process monitoring method using extended KNN imputation based LOF prediction. Existing rule-based approaches to process monitoring has some limitations like late alarm for fault occurrence or no indicators about real-time progress, since there exist unobserved attributes according to the monitoring phase during process executions. To improve these limitations, we propose an algorithm for LOF prediction by adopting the imputation method to assume unobserved attributes. LOF of ongoing instance is calculated by assuming next probable progresses after the monitoring phase, which is conducted during entire monitoring phases so that we can predict the abnormal termination of the ongoing instance. By visualizing the real-time progress in terms of the probability on abnormal termination, we can provide more proactive operations to opportunities or risks during the real-time monitoring.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.2
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• pp.202-207
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• 2013

RFID technology is applied to port logistics applications since it monitors objects wirelessly without line of sight and constructs ubiquitous system with low cost. Changes of stock status in the warehouse environment make the technology more important for managing such frequent storing and un-storing. Although the RFID has beneficial characteristics of low cost and low complexity, simultaneous responses of RFID tags cause tag identification collision due to absence of elaborate medium access control scheme. Several algorithms have been proposed to overcome the tag collision problem. However, it is difficult to adopt the methods to the logistics systems that has varying loads since there was no consideration on RFID tag's mobility. Therefore, we propose an efficient RFID tag anti-collision protocol, and simulation results demonstrate performance improvement by using the proposed scheme.