• Journal of Korea Multimedia Society
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• v.14 no.6
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• pp.835-848
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• 2011

In this paper, we propose a client server based distributed/parallel system to effectively visualize huge geographic data. The system consists of a web-based client GUI program and a distributed/parallel server program which runs on multiple PC clusters. To make the client program run on mobile devices as well as PCs, the graphical user interface has been designed by using JOGL, the java-based OpenGL graphics library, and sending the information about current available memory space and maximum display resolution the server can minimize the amount of tasks. PC clusters used to play the role of the server access requested geographic data from distributed disks, and properly re-sample them, then send the results back to the client. To minimize the latency happened in repeatedly access the distributed stored geography data, cache data structures have been maintained in both every nodes of the server and the client.

• Journal of the Korean Academic Society of Industrial Cluster
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• v.4 no.1
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• pp.1-13
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• 2010

The T-DMB which was developed by the convergence of digital broadcasting technology and communication technology provides us with very good quality of music like CD, and provides TV services in a super express train like the KTX whose velocity is over 300 Km per hour. The T-DMB is diffusing toward the world as a technology which is be able to provide the various convergent services of broadcasting and communication through mobile phone, PDA, dedicated terminal, and so on. A business model needed for the diffusion of the T-DMB toward the world was established and utilized to expand the T-DMB into Vietnam in the paper. In addition, this paper describes a case for the establishment of the T-DMB system in order to provide the paid services in Vietnam. It is expected that the expansion of the T-DMB into Vietnam will make a great contribution to the diffusion of the T-DMB toward the world.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.6
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• pp.41-46
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• 2019

In this paper, it is necessary to study the bandwidth and network system for efficient image transmission in the current era of drone imaging, and to design routing protocols to round out and cluster two or more multi-drones. First, we want to construct an ad hoc network to control the multidrone. Several studies are underway for the clustering of drones. The aircraft ad hoc network (FANET) is an important foundation for this research. A number of routing protocols have been proposed to design a FANET, and these routing protocols show different performances in various situations and environments. The routing protocol used to design the FANET is tested using the routing protocol used in the existing mobile ad hoc network (MANET). Therefore, we will use MANET to simulate the routing protocol to be used in the FANET, helping to select the optimal routing protocol for future FANET design. Finally, this paper describes the routing protocols that are mainly used in MANET and suitable for FANET, and the performance comparison of routing protocols, which are mainly used in FANET design.

• Journal of Communications and Networks
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• v.10 no.2
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• pp.137-147
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• 2008

This paper proposes a novel approach to interference avoidance via inter-cell relaying in cellular OFDMA-TDD (orthogonal frequency division multiple access - time division duplex) systems. The proposed scheme, termed asymmetry balancing, is targeted towards next-generation cellular wireless systems which are envisaged to have ad hoc and multi-hop capabilities. Asymmetry balancing resolves the detrimental base station (BS)-to-BS interference problem inherent to TDD networks by synchronizing the TDD switching points (SPs) across cells. In order to maintain the flexibility of TDD in serving the asymmetry demands of individual cells, inter-cell relaying is employed. Mobile stations (MSs) in a cell which has a shortage of uplink (UL) resources and spare downlink (DL) resources use free DL resources to off-load UL traffic to cooperating MSs in a neighboring cell using ad hoc communication. In an analogous fashion DL traffic can be balanced. The purpose of this paper is to introduce the asymmetry balancing concept by considering a seven-cell cluster and a single overloaded cell in the center. A mathematical model is developed to quantify the envisaged gains in using asymmetry balancing and is verified via Monte Carlo simulations. It is demonstrated that asymmetry balancing offers great flexibility in UL-DL resource allocation. In addition, results show that a spectral efficiency improvement of more than 100% can be obtained with respect to a case where the TDD SPs are adapted to the cell-specific demands.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.1
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• pp.167-172
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• 2017

Mobile nodes are used for prolonging the life-time of the entire wireless sensor networks and many studies that use drones to collected data have been actively conducted with the development of drone related technology. In case of associating a drone and tactical wireless sensor networks, real-time feature and efficiency are improved. The previous studies so focus on reducing drone's flight distance that the energy consumption of sensor nodes is unbalanced. This unbalanced energy consumption accelerates the network partition and increases drone's flight distance. In this paper, we proposed a new selection scheme considered drone's flight distance and nodes' life-time to solve this problem when rendezvous nodes that collect data from their cluster and directly communicate with a drone are selected.

• Natural Product Sciences
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• v.17 no.2
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• pp.147-159
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• 2011

A high-performance liquid chromatography-electrospray ionization-tandem mass spectrometric method was developed to determine simultaneously eight marker constituents of Forsythiae fructus, and subsequently applied it to classify its two botanical origins. The marker compounds of Forsythia suspensa were phillyrin, pinoresinol, phillygenin, lariciresinol and forsythiaside; those of F.viridissima were arctiin, arctigenin and matairesinol. Separation of the eight analytes was achieved on a phenyl-hexyl column (150${\times}$2.0 mm i.d., 3 ${\mu}M$) using gradient elution with the mobile phase: (A) 10% acetonitrile in 0.5% acetic acid, (B) 40% aqueous acetonitrile. A few fragment ions specific to the types of lignans, among the product ions generated by collisonally induced dissociation (CID) of molecular ion clusters, such as [M-H]$^-$ or [M+OAc]$^-$ were used not only for fingerprinting analysis but for the quantification of each epimer by using multiple-reaction monitoring mode. It was shown good linearity ($r^2{\geq}$ 0.9998) over the wide range of all analytes; intra- and inter-day precisions (RSD, %) were within 9.14% and the accuracy ranged from 84.3 to 115.1%. The analytical results of 40 drug samples, combined with multivariate statistical analyses - principal component analysis (PCA) and hierarchical cluster analysis (HCA) - clearly demonstrated the classification of the test samples according to their botanical origins. This method would provide a practical strategy for assessing the authenticity or quality of the herbal drug.

• Journal of Digital Convergence
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• v.14 no.2
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• pp.271-278
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• 2016

University-industry cooperation is indispensable for a short-term problem solving, as well as sustainable growth in the economy of the Republic of Korea. In order to embody and implement that, the government has run a variety of financial assistance programs and policies for the promotion of the cooperation for the last 10 years, and Korea Sanhak Foundation has made progress in academic and research development support, creative personnel training and scholarships, International Support and other projects. In this paper, window-type university-industry convergence and practices, and analyzing the best practices of national and international IT-based fusion technology, corporate cooperation were established to support measures taken in conjunction type and model of the university. Industry utilizing the latest IT technology based on this model, academia, proposed a collaboration system between workers building measures.

• The Research Journal of the Costume Culture
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• v.18 no.5
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• pp.991-1002
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• 2010

Nowadays, personal media is a new tool for communication as digital cameras and mobile phones are developing rapidly. We are concerned over Cyworld users who could have different personal characteristics which will influence on buying patterns in on line shopping behaviors. The purpose of this research was to observe fashion attitudes and purchase behavior of Cyworld mini homepage users, for establishing marketing strategies by understanding consumers. For this study, one line survey was used for 500 male and female subjects who are 20 to 40 years old. Only reliable 441 questionnaires were used for analysis. The SPSS program was used for frequency, K-means cluster, t test, and chi-square test. A total of 441 respondents were clustered on the basis of 8 item self-disclosure scale, using the K-means procedures. The results indicated that respondents were clustered into two segments; 267 respondents(active attitude towards self-disclosure) and 164 ones(not active). We examined fashion attitudes in mini home page and buying behavior by self-disclosed variable. Those who are involved actively in self expression and self-disclosure considered more fashion style and trend. The major motivates of web surfing was finding a good design, and good price. High self-disclosure group tends to search many shopping mall for right design and low self disclosure group tends to search them for the right price. High self-disclosure group tend to shop the fashion products more, while low self disclosure group tend to purchase books more through the internet. We realized that active group in self-disclosure purchased their clothing accidently when they visit Cyworld.

• International Journal of Human Ecology
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• v.16 no.2
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• pp.79-88
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• 2015

As information and communications technology (ICT) becomes increasingly integrated into the daily lives of people around the world, it is important to know how the technology is influencing the behaviors of individuals and families. This study looked at the ecology of families as it is related to ICT and the changes to processes that occur as ICT devices and services are integrated into the family. A survey of 1084 families was conducted. Five hundred of the families were from the United States and 584 families were from Korea. Significant differences were found in the use of ICT by Korean and American families although the source of this difference was not clearly identified in this study. Three clusters of families were identified based on their use of devices and services. These were labeled as; 'The Tech Savvy', 'The Wireless Users', 'The In-betweeners', 'The Wired', and 'The Just Mobile'. 'The Tech Savvy' used the greatest variety of ICT technologies and 'The Wired' used the fewest. Other clusters fell in the middle with families seemingly using the devices which met their particular needs. Two factors related to ICT integration into the family were identified. These were related to family intimacy and family relationship maintenance. The family cluster identified as 'Tech Savvy' made significantly greater use of ICT in these relationships and 'The Wired' made the least use of ICT in these areas. The other clusters tended to be between the two ends and tended not to be significantly different from each other in their use of ICT. Finally, models for ICT use by families showed that demographics, nation of origin, types of devices and services used, and attitude and interest in ICT all had a significant impact.

• Bulletin of the Korean Chemical Society
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• v.30 no.1
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• pp.137-144
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• 2009

In this study, quantitative and pattern recognition analyses for the quality evaluation of Herba Epimedii using HPLC was developed. For quantitative analysis, five major bioactive constituents, hyperin, epimedin A, epimedin B, epimedin C, and icariin were determined. Analysis was carried out on Capcell pak $C_{18}$ column ($250{\time}4.6$ mm, 5 ${\mu}m$) with a mobile phase of mixture of acetonitrile and 0.1% formic acid, using UV detection at 270 nm. The linear behavior was observed over the investigated concentration range (2-50 ${\mu}g/mL;\;r_2\;>$ 0.99) for all analytes. The intraand inter-day precisions were lower than 4.3% (as a relative standard deviation, RSD) and accuracies between 95.1% and 104.4%. The HPLC analytical method for pattern recognition analysis was validated by repeated analysis of one reference sample. The RSD of intra- and inter-day variation of relative retention time (RRT) and relative peak area (RPA) of the 12 selected common peaks were below 0.8% and 4.7%, respectively. The developed methods were applied to analysis of twenty Herba Epimedii extract samples. Contents of hyperin, epimedin A, epimedin B, epimedin C, and icariin were calculated to be 0$\sim$0.79, 0.69$\sim$1.91, 0.93$\sim$9.58, 0.65$\sim$3.05, and 2.43$\sim$11.8 mg/g dried plant. Principal component analysis (PCA) showed that most samples were clustered together with the reference samples but several apart from the main cluster in the PC score plot, indicating differences in overall chemical composition between two clusters. The present study suggests that quantitative determination of marker compounds combined with pattern-recognition method can provide a comprehensive approach for the quality assessment of herbal medicines.