• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.6A
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• pp.624-634
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• 2008

The mobile station which is about to do handover in IEEE 802.16e networks scans its neighboring base station channels to decide its next target base station. However, due to the lack of location information of its subscribers, the serving base station cannot provide any reliable candidate channel which is actually attachable by the scanning mobile stations, which makes the mobile station suffer from the long scanning time. Sometimes, long scanning time may cause the degradation of quality of service due to repeatable scan-duration or failure to start the handover procedure in time. To overcome these problems, in this paper, we propose a new protocol so called fast group scanning scheme, in which multiple mobile stations form a group to scan their neighboring base station channels simultaneously. Main contribution of this proposal is to find and decide a reliable target base station within a short scanning time. The fast group scanning scheme can be deployed to the cell network of the serving base station with a dynamic neighboring base station list management.

• Journal of KIISE:Computer Systems and Theory
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• v.36 no.5
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• pp.327-334
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• 2009

The tiled-display system provides a high resolution display which can be used in different applications in co-working area. The systems used in the co-working field usually save the user logs, and these log information not only makes the maintenance of the tiled-display system easier, but also can be used to check the progress of the co-working. There are three main steps in the proposed tiled display log recorder. The first step is to capture the screen shots of the tiles and send them for merging. The second step is to merge the captured tile images to form a single screen shot of the tiled-display. The final step is to encode the merged tile images to make a compressed video stream. This video stream could be stored for the logs of co-working or be streamed to remote users. Since there could be differences in capturing time of tile images, the quality of merged tiled-display could be degraded. This paper proposes a time stamp-based metric to evaluate the quality of the video stream, and a merging algorithm that could upgrade the quality of the video stream with respect to the proposed quality metrics.

• Journal of Internet Computing and Services
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• v.5 no.1
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• pp.51-57
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• 2004

Mobile Internet allows users to request critical information and receive swift responses at any places, but mobile users could suffer from unreliable and ill-timed services due to the characteristics of wireless media, One way that reduces possibility of the unsatisfactory services is data replication. Data Replica1ion, however, inevitably induces the overhead of maintaining replica consistency which requires more expensive synchronization mechanism. We propose a new replicated data management scheme in distributed mobile environment, In order to alleviate negative impact of synchronization message overhead in fault-prone mobile Internet environment, we devise a new replication control scheme called proxy quorum consensus (PQC), PQC minimizes the message overhead by coordinating quorum access activities by means of proxy mediated voting (PMV) which exploits reliable proxy hosts instead of unreliable mobile hosts in voting process, We also propose a simulation model to show the performance of PQC. Based on the results of the performance evaluation, we conclude that PQC scheme outperforms the traditional schemes.

• Journal of KIISE:Computer Systems and Theory
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• v.28 no.12
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• pp.642-652
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• 2001

Recently, the advent of World-Wide-Web(WWW) and the explosive popularity of the Internet gave birth to collaborative applications which were enabled by computers and networks as their primary media. The progress of 3D computer graphics enabled collaborative application with 3D virtual environments or distributed virtual environments. In this paper, we explain our implementation of the Share collaboration engine which is for collaboration applications based on a distributed virtual environment. We introduce Virtual Architectural Engineering 2000 (VAE2000) that is our pilot application implemented with the Share collaboration engine. The Share collaboration engine proposes a new Share network architecture for management of participants, and it provides some synchronization methods for 3D objects in virtual collaboration. VAE2000 is an experimental application that tries to prevent wastes of human, material and time resources in networked virtual collaboration.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.2
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• pp.385-390
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• 2017

Owing to the development of IT technology, a computerized system in various ways such as a variety of company's businesses, factory automation system and hospital healthcare system is introduced and operated. And it is possible to say that a computer system is more important than anything else to the extent that all businesses are suspended in case the system is down. Attention should be always paid to environmental management such as temperature, humidity and fire in server room for the normal operation of system in this situation. It is thought that there is necessity for a low-cost system which independently monitors environment round the clock in the situation where the person in charge doesn't pay attention and which informs a person in charge in real time when an event occurs for the operation of this small server room. Consequently, it is to be hoped that the suspension of service provided by computer system, which may occur due to a specific event, can be prevented.

• Journal of Convergence for Information Technology
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• v.7 no.5
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• pp.89-93
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• 2017

As the cost of installing and maintaining software on large organizations such as recent companies and schools has increased, software installation and maintenance costs are low, system management is easy, demand for ease of use software solutions has increased. In the reality that special education for service center engineers is required along with the release of various products, training of the software and solution industry is regarded as important. Building Web-based user and system interactive environment, strengthened usability and educational ability effect suitable for engineer level. In the future, research that is familiar with specific software, not successfully combining multiple frameworks, rather than developers, will be increasingly important for research that can achieve optimal performance.

• Journal of the Korea Society of Computer and Information
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• v.16 no.7
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• pp.95-103
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• 2011

The actual utilization of Semantic Web technology which aims to provide more intelligent and automated service for information retrieval over the Web becomes gradually reality. RDF is widely used as the one of standard formats to present and manage the voluminous data on the Web. Efficient query processing on RDF data, therefore, is one of the ongoing research topics. Retrieving resources having a specific association from a given resource is the typical query processing type and several researches for this have done. However the most of previous researches have not fully considered discovering the complex relationship among resources such as returning the association between resources as the query processing result. This paper introduces the indexing and query processing for ${\rho}$-intersect operation which is one of the semantic association retrieval types. It includes an indexing scheme using suffix array and optimal processing approaches for handling ${\rho}$-intersect operation. The experimental evaluations shows that the average execution times for the proposed approach is 3~7 times faster than the previous approach.

• The Journal of the Acoustical Society of Korea
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• v.32 no.3
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• pp.269-278
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• 2013

The speech recording of the National Archives of Korea contains very important traces which represent modern times of Korea. But the way to be recorded by analogue is easily contaminated as time goes by. So it has to be digitalized for management and services. Consequently, restoration method of distorted speech is needed. We propose the four classes for each distortion kind and apply restoration algorithms for the cases of speech level, stationary noise and abrupt noise. As a result, speech volume adjusts to -26 dBov for only on the speech region and SNR improves above 10dB. Especially, conventional way to remove the noise is almost impossible because we need to listen to all of them but it can be more effective by adaptation of auto restoration algorithm.

• Journal of the Korea Convergence Society
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• v.11 no.9
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• pp.193-202
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• 2020

The aim of this paper is to analyze parking characteristics and demand of A general hospital(A hospital) based on data on entries·exits in parking lot and to improve parking service to patients and visitors without building new parking spaces. To improve the quality of parking service we analyze average parking duration, parking turnover, peak hour, parking index and parking demand of A hospital. Using the results of this research we can improve parking regulations and operate a parking lot smartly. Other hospitals of similar size of A hospital can also refer to these results to improve parking service and build a smart parking system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.7
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• pp.1498-1508
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• 2003

It is important to integrate an enterprise application for automating of the business process, which is responded by a flow of market environment. There are two categories of method that integrate enterprise applications. One is Synchronous Integration, and the other is Asynchronous Integration. EAI(Enterprise Application Integration) and Web service which of the asynchronous integration is focused in the automating method of the business process. After we construct the application integration for automating of the business process, we have to concern about managing of the business transaction. Many Organizations have proposed the process method of business transaction based on 2-phase commit protocol. But this method can't supply the phase that classify the transaction by transaction weight. In this Paper, we Propose an efficient method of transaction process for business transactions, which is composed by ‘Classify Phase’ that classify transactions. We called this model “3-Phase Commit Method Applied by Classify Phase”, we design this model to manage an resource of enterprise efficiently. The proposed method is compared by the method based on 2-Phase commit that could be a problem of management the resource of enterprise, and the advantage of this method is certified to propose the solution of that problem.