• Journal of KIISE
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• v.44 no.10
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• pp.1005-1018
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• 2017

Recently, virtualization has become an essential component of cloud computing due to its various strengths, including maximizing server resource utilization, easy-to-maintain software, and enhanced data protection. However, since virtualization allows sharing physical resources among the VMs, the system performance can be deteriorated due to device contentions. In this paper, we first investigate the I/O overhead based on the number of VMs on the same server platform and analyze the block I/O process of the KVM hypervisor. We also propose an in-memory block cache mechanism, called QBic, to overcome I/O virtualization latency. QBic is capable of monitoring the block I/O process of the hypervisor and stores the data with a high access frequency in the cache. As a result, QBic provides a fast response for VMs and reduces the I/O contention to physical devices. Finally, we present a performance measurement of QBic to verify its effectiveness.

• KIISE Transactions on Computing Practices
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• v.22 no.10
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• pp.488-496
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• 2016

In this paper, we introduce a virtual reality interface for scientific visualization applications. Our VR interface is based on an open-source framework called VR Juggler. Although VR Juggler has its own advantages, it lacks some of the important functionalities needed for practical applications - event handling, synchronization and data sharing among cluster nodes, to name a few. We explain how these issues are resolved while developing the VR interface. Also, a new interface with a smart device, which replaces the virtual reality input device, is introduced. Finally, system usability test results are provided to prove the effectiveness of the proposed interfaces.

• Journal of the Korea Computer Industry Society
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• v.5 no.3
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• pp.383-392
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• 2004

Electronic BBS (bulletin board system) Ins been widely recognized as an appropriate medium for exchanging ideas and sharing information asynchronously. The communication ability if BBS is the main reason for utilizing it as a tool for collaborative learning. Researchers in the community reported a number if findings regarding the educational utilization if BBS recently. In this paper, we propose a qualitative method to measure communication activities using BBS so that the complex discussion behaviors of participants can be understood analytically. We propose characteristic vectors to describe discussion behaviors of groups and individuals, which can be conveniently used for characterizing and comparing discussion groups as well as individuals. The interactivity model representing interactive activities shows graphically the degree of inter activity if discussion groups as well as individuals. Also, time dependent measurements are investigated to analyze discussion activities with time. Experiments on the proposed measurements conducted on the Web-based discussion project using BBS demonstrate how measurements can be carried out, how characteristic vectors and inter activity model can be constructed and used.

• Journal of Korea Multimedia Society
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• v.7 no.3
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• pp.388-398
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• 2004

This paper focuses on the reduction method of message traffic occurred when multiple participants collaborate in the distributed virtual environment. It is referred to as filtering method of update message to minimize data traffic exchanged in the virtual environment, and it is the essential process to improve the scalability of the virtual environment. Spatial partitioning method, a popular filtering technique, divides the whole environment into smaller sub-parts in order to make it small the regions to be maintained consistently. However, it is less flexible and adaptable because the information of area of interest must be configured before simulation. In this paper, the concept of dynamic area of interest is proposed, which is highly adaptable by applying dynamic environmental elements to AOI management. It uses multiple layering and multiple consistency algorithms for dynamic management, and makes it possible to consume system resource efficiently. For performance evaluation, experiments are performed with virtual avatars, measuring message traffic. Finally, the proposed model could be applied to the AOI management systems which accommodate massive users like MMORPG, or virtual communities.

• Journal of Advanced Navigation Technology
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• v.20 no.6
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• pp.503-510
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• 2016

In recent years, owing to the growing user demand for the two-way internet service based on the move global broadband communications, a new type of satellite terminal has developed, known as earth station in motion (ESIM). This service was required by Resolution 158 (WRC-15) to study on the coexistence with the co-primary fixed service (FS) in 27.5-29.5 GHz as a FSS uplink. In this paper, four scenarios was introduced to account for the antenna pointing error and the azimuth for an analysis on the sharing between ESIM and FS. From analysis results, the required separation distance between two systems should be about 32~52 km according to the elevation angles of $20^{\circ}{\sim}40^{\circ}$ using thresholds of 5% and 10% outage probability. Therefore, it is necessary to control the azimuth angle due to a moving terminal as well as the pointing error of ESIM to minimize the required separation distance and to protect the co-primary FS.

• Journal of the Korea Computer Industry Society
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• v.8 no.4
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• pp.207-220
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• 2007

Recording to development of info-communication, recent educational paradigm asks not for a passive transmitter but an active constructor who can solve the various complicated problems in real situations. Such a change asks for the educational setting which includes sharing ideas and information rather than possessing them by themselves. Learning through presentation has many problems which are few chances of presentation as well as reusing of presentation data. etc. This study suggested the strategy which are promoting interactions through presentation class and using practically. For this, role of the presentation data provider and learner was suggested, also strategies to implement of the presentation learning support system step by step. Through the strategy of this paper could maintain the active communicating relationship between the learners. Without the limitation of the time and space, the real time communication is made while looking at the presentation data of the other party, the teaming effect by the presentation teaming strategy is expected to be high.

• The Journal of the Korea Contents Association
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• v.16 no.9
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• pp.612-627
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• 2016

This study is research on the snack culture and fast fashion. The purpose of this study is to examine the common attributes of snack culture and fast fashion as a cultural phenomenon. The following results were obtained: First, snack culture and fast fashion have attributes of 3S represented by Speed, Short time, and Simplification. Second, snack culture and fast fashion meet consumer demands by fun and various contents and a variety of designs, respectively. Third, although snack culture has developed on the basis of information technology, fast fashion has grown based on the technological innovation of business, organization, and distribution system. Fourth, snack culture communicates with the world through opening and sharing to be globalize a context, and fast fashion is globalized to multinational corporations by increasing sales and development of scale. Fifth, snack culture has a synergistic effect by maximizing the multiple interactions through social campaigns based on the attribute to communicate with many-to-many relationship. In addition, fast fashion produces a synergistic effect through collaborative strategic alliances.

• The KIPS Transactions:PartC
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• v.13C no.2 s.105
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• pp.249-258
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• 2006

WebDAV is an IETF standard protocol, which is an extended version of HTTP 1.1, supporting asynchronous collaborative authoring of various contents on the web. Recently, to precisely control access to the resources on a WebDAY server, the WebDAV Access Control Protocol was published. This protocol helps developers to implement advanced server functionalities in a convenient way by providing various control methods to the resources on the WebDAV server. Based on the WebDAV access control protocol, we developed Open Workspaces, which systematically support exchanging and sharing data for general visitors. An Open Workspace can be supplied as a Download-Only Open Workspace, an Upload-Only Open Workspace, or an Upload-Download Open Workspace. Any registered user can create these workspaces without bothering the system administrator. To support the Open Workspaces, we extended the Slide WebDAV server and the DAVExplorer WebDAV client, which are being used popularly.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.31 no.3
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• pp.12-25
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• 2018

Objectives : The purpose of this study is to analyze the use of herbal medicine for the treatment of urticaria in case studies and to find the general tendency of herbal medicine treatment and to establish the primary treatment direction of urticaria. Methods : In the domestic databases, Oriental medicine Advanced Searching Integrated System (OASIS), Korean Traditional Knowledge Portal (KTKP), National Discovery for Science Leader (NDSL), Research Information Sharing Service (RISS), we selected among the case study papers published in the last 20 years using search terms related to "urticaria". Reports related to Sasang Constitutional medicine were excluded and total of 15 papers were finally selected. Results : 23 prescriptions were retrieved from 15 papers. The most commonly used prescription was Seungmagalgeun-tang (升麻葛根湯), and Bangpoongtongsung-san (防風通聖散) and Pyeongwi-san (平胃散) were presented twice. Commonly used herbs are Glycyrrhizae Radix et Rhizoma (甘草), Zingiberis Rhizoma Recens (生薑), and Scutellariae Radix (黃芩). 18 out of 78 herbs are belonging to heat-clearing medicinal (淸熱藥) and 16 out of 78 herbs are belonging to exterior-releasing medicinal (解表藥). Concurrent therapies such as acupuncture, pharmacoacupuncture, moxibustion, cupping therapy, ice pack applying therapy were performed and several evaluation methods were used, patient's subjective remission rate was the most used. Conclusions : Through this study, we were able to discover the tendency of herbal medicine prescription for the treatment of urticaria.

• The Journal of Society for e-Business Studies
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• v.12 no.4
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• pp.165-184
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• 2007

Recently, blogging has been regarded as a promising media for information sharing and relationship building. However, it is not quite sure if the technology acceptance model could be completely adopted also in relationship-based system such as blog. Hence, the purpose of this paper is to identify the factors affecting the usage of blogs. To do so, content analysis methodology is applied to extract meaningful factors affecting the usage of blogs in the opinions of the bloggers in a Korean portal site : Naver. We investigates the causal relationship among three factors ; perceived usefulness, perceived encouragement, and actual use in blogging. Moreover, public self-consciousness, self disclosure and telepresence are also considered as the determinants. The results show that public self-consciousness and self disclosure are significant elements affecting perceived usefulness and perceived encouragement, while perceived usefulness and perceived encouragement both affecting the actual use of blogs.