• Journal of Korea Water Resources Association
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• v.36 no.6
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• pp.949-960
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• 2003

The resolution issue of wetness index with relaxation of the steady state assumption is explored on the platform of Digital Elevation Model (DEM). The variabilities of the quasi-dynamic wetness index and the dynamic wetness index are discussed on the base of the spatial and statistical aspects depending upon resolutions of DEM and the drainage time. The organization patterns of the wetness index can be observed upon various drainage times and pixel size. The transient behaviour of wetness patterns of the Sulmachun watershed are shown in the relatively short drainage time. The statistical analysis of the quasi-dynamic and dynamic wetness analysis provide the convergence of analysis results to the steady state characteristics later than 10,000 hours drainage time. The probability density functions of the quasi-dynamic and the dynamic wetness index shows the existence of the threshold pixel size of DEM which provide stability and consistency in the computation result of these two wetness index.

• Journal of Digital Contents Society
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• v.11 no.2
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• pp.203-216
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• 2010

This study analyzed educational applications in smartphones with some criteria seeking to apply online learning characteristics to smartphones. For the analysis, 85 educational applications were selected and they were classified by types of educational contents, interactions, and the combination of the educational contents and interactions. As a result, drill-and-practice and tool types of contents ranked high, and there found to be few simulation and problem solving types. In regard to interaction types, almost all of the applications had interactions only between contents and learners, which meant little active communications when using applications. Therefore, enhanced interactions and communications among learners using the social network service platform were required in order to use educational applications in a more effective way.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.29 no.3
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• pp.303-309
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• 2011

Situation awareness services which increasingly expand their influence in everyday life can be classified into location-based service and social network service. Their quality of service (QoS) can be differed based on the location accuracy of smart phones and accuracy of directional recognition technology. This study was conducted to analyze GPS, digital compass, radio communication, and geospatial web information which can provide a clue in using the situation aware services based on lab experiments and surveys. According to the result of lab experiment on accuracy of determining location / direction with smart phones, owing to inherent lack of indoor accuracy in determining position and direction, as well as errors in spatial data used as platform, it was found that devices were not provided with sufficiently accurate data when using the situation aware services indoors compared to outdoors. To enhance accuracy of determining indoor positions, there are several methods including location metering based on Wi-Fi, which had several problems compared with GPS used in outdoor environment. Thus, it was determined that more study would be necessary to solve these issues.

• KIPS Transactions on Software and Data Engineering
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• v.4 no.8
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• pp.301-308
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• 2015

SNS is a web-based online platform service supporting the formation of relations between users. SNS users have usually used a desktop or laptop for this purpose so far. However, the number of SNS users is greatly increasing and their access to the web is improving with the spread of smart phones. They share their daily lives with other users through SNSs. We can detect events if we analyze the contents that are left by SNS users, where the individual acts as a sensor. Such analyses have already been attempted by many researchers. In particular, Twitter is used in related spheres in various ways, because it has structural characteristics suitable for detecting events. However, there is a limitation concerning the detection of events and their locations. Thus, we developed a system that can detect the location immediately based on the district mentioned in Twitter. We tested whether the system can function in real time and evaluated its ability to detect events that occurred in reality. We also tried to improve its detection efficiency by removing noise.

• Journal of KIISE:Computing Practices and Letters
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• v.6 no.3
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• pp.288-298
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• 2000

Digital assets denote multimedia information that exists in the form of digitized materials such as images, audio, and video. The management of digital assets demands much effort because of a huge amount of storage space requirement and multidimensional characteristics of the information needed to describe their contents. In this paper, we design and implement a Digital Asset Manager that stores and manages digital assets efficiently. Among the various types of digital assets, we focus on the video asset which has the highest complexity. Our Digital Asset Manager provides various facilities for digital contents authoring applications. In the Digital Asset Manager, video assets are managed by using a hierarchical model in order to ensure efficient accesses to any part of a video asset. Our system also guarantees the independence from the storage platform, and provides a fast content-based similarity search method on the digital assets.

• The Journal of the Korea Contents Association
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• v.8 no.7
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• pp.9-16
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• 2008

The design and implementation of the interaction for tangible user interfaces require in-depth knowledge in many different disciplines, such as device control, sensing and calibrating devices, interaction design, low-level programming, and performance tuning. Many trial and error iterations are needed to determine the proper combination of the interaction techniques while using available interaction devices and considering the characteristics of contents. As a result, it takes too much effort and time to achieve maximum usability. This paper introduces a tangible user-interface platform, which is fabricated using various hardware devices and an XML-based authoring tool, which is developed in order to relieve content creators of the burden of the above difficulties. Finally, we demonstrate our work by illustrating some example contents.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.8 no.4
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• pp.161-176
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• 2013

This study discusses some features observed in Korean credit card industry, which is classified as a two-sided market. First, I summarize six characteristics or conditions that two-sided markets possess by reviewing related literatures, and consider if we can find out those peculiarities in Korean card industry. Second, this study casts light upon the unique issues which have not been handled in previous studies, that is another two-sidedness in mature two-sided markets. In the context of credit card industry, this additional two-sidedness is created by specific consumers group existing in entire consumer group in a card firm as a form of subset and specific partnering merchants group offering special benefits to their subset consumer group, or alliance card holders. This concept gives new idea that there could be multiple two-sidedness especially in mature two-sided markets, which will be significant to platforms' pricing strategies and expand the scope of related studies.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.8
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• pp.1456-1463
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• 2010

The safety critical systems in nuclear power plants should be designed to have a high level of fault tolerant capability because those systems are used for protection or mitigation of the postulated accidents of nuclear reactor. Due to increasing of the system complexity of the digital based system in nuclear fields, the reliability of the digital based systems without an auto-test or a self-diagnostic feature is generally lower than those of analog system. To overcome this problem, additional redundant architectures in each redundant channel and self-diagnostic features are commonly integrated into the digital safety systems. The self diagnostic function is a key factor for increasing fault tolerant capabilities in the digital based safety system. This paper presents an availability and safety evaluation model to analyze the effect to the system's fault tolerant capabilities depending on self-diagnostic features when the loss or erroneous behaviors of self-diagnostic function are expected to occur. The analysis result of the proposed model on the several modules of a safety platform shows that the improvement effect on unavailability of each module has generally become smaller than the result of usage of conventional models and the unavailability itself has changed significantly depending on the characteristics of failures or errors of self-diagnostic function.

• International Journal of Industrial Entomology and Biomaterials
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• v.37 no.1
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• pp.1-8
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• 2018

The nerippe fritillary butterfly, Argynnis nerippe, is listed as an endangered species in Korea. Establishment of effective conservation strategies can be aided by the development and application of molecular markers that can be used to investigate the population genetics of the butterfly. Therefore, in this study, we identified ten microsatellite markers specific to A. nerippe using the Next-Seq 500 platform, and applied these markers to investigate the characteristics of five South Korean butterfly populations. Genotyping of 48 A. nerippe individuals from five localities showed that at each locus the number of alleles ranged from 4 to 14, and that the observed and expected heterozygosities were 0.324-0.863 and 0.138-0.985, respectively. Significant deviation from the Hardy-Weinberg equilibrium was not observed at any locus. Population structure analysis indicated that there are two genetic groups in Korea, but no population-based gene pool assignments were found. Analysis of $F_{ST}$, $R_{ST}$, and a principal coordinates analysis suggested that the Gureopdo and Yaecheon populations were isolated from other populations. Genetic isolation of the Gureopdo population may be a consequence of unequal population change between Gureopdo and inland populations and to the offshore habitat of Gureopdo. Genetic isolation of the Yaecheon population may be a consequence either of the southernmost location of the population or of the limited sample size available. Further studies with increased sample sizes will be necessary to draw robust conclusions on population isolation and to devise conservation strategies.

• Journal of Korea Society of Digital Industry and Information Management
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• v.13 no.4
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• pp.141-151
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• 2017

Nowadays, It is undeniable that the threat of network security is growing as time flows due to worldwide development of wire/wireless, various Internet platform and sophisticated hacking techniques. The amount of traffics that Network security solution has to handle is increasing and recently many occurrence of explosive traffic attacks from PulseWave are being observed which has many similar characteristics to New DDos. Medium and small sized firms abroad have developed and distributed Snort and Suricata that are based on open-source Intrusion Detection System(IDS) / Intrusion Prevention System (IPS). The goal of this study is to compare between Windows7 by applying suicata 4.0.0 32bit version and Ubuntu 16.04.3 LTS by applying suicata 4.0.0 version which is an open source Intrusion Detection System / Intrusion Protection System that uses multi threads method. This experiment's environment was set as followed C1100 server model of Dell, Intel Xeon CPU L5520 2.27GHz*2 with 8 cores and 16 threads, 72GB of RAM, Samsung SSD 250GB*4 of HDD which was set on RAID0. According to the result, Suricata in Ubuntu is superior to Suricata in Windows7 in performance and this result indicates that Ubuntu's performance is far advanced than Windows7. This meaningful result is derived because Ubuntu that applied Suricata used multi core CPU and RAM more effectively.