• Journal of the Korea Computer Industry Society
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• v.3 no.9
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• pp.1251-1260
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• 2002

Real-time application programs have synchronization constraints which need to be met between media-data. Synchronization method represents feedback method including virtual client-side buffer. This buffer is used in buffer level method. It is client-leading synchronization that is absorbing variable transmission delay time and that is synchronizing by feedback control. It is the important factor for playback rate and QoS if the buffer level is normal or not. To solve the problems, we can control the start of transmission in multimedia server by appling filtering, control and network evaluation function. Synchronization method is processing for smooth presentation without cut-off while media is playing out. When audio frame which is master media is in high threshold buffer level we decrease play out time gradually, otherwise we increase it slowly.

• Journal of KIISE:Information Networking
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• v.37 no.5
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• pp.409-414
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• 2010

The applications based on geographical location are increasing rapidly in wireless sensor networks (WSN). Recently, various localization algorithms have been proposed but the majority of algorithms rely on the specific hardware to measure the distance from the signal sources. In this paper, we propose the Weighted Multiple Rings Localization(WMRL). We assume that each deployed anchor node may periodically emit the successive beacon signals of the different power level. Then, the beacon signals form the concentric rings depending on their emitted power level, theoretically. The proposed algorithm defines the different weighting factor based on the ratio of each radius of ring. Also, If a sensor node may listen, it can find the innermost ring of the propagated signal for each anchor node. Based on this information, the location of a sensor node is derived by a weighted sum of coordinates of the surrounding anchor nodes. Our proposed algorithm is fully distributed and does not require any additional hardwares and the unreliable distance indications such as RSSI and LQI. Nevertheless, the simulation results show that the WMRL with two rings twice outperforms centroid algorithm. In the case of WMRL with three rings, the accuracy is approximately equal to WCL(Weighted Centroid Localization).

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.8A
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• pp.683-690
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• 2011

The conventional sensor tag data filtering algorithm uses time window based data filtering for each tag data. However, this approach shows many performance problems such as low error and event detection rate and larger storage size requirement. In this paper, we propose a collaborative sensor tag data filtering algorithm to improve sensor data processing performance. simulation study shows that the proposed sensor tag filtering algorithm outperforms the conventional filtering algorithm in terms of the processing time, the size of required data storage memory and accuracy of error and event detection rate.

• The Transactions of the Korea Information Processing Society
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• v.1 no.4
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• pp.490-501
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• 1994

In this study the problems of cell marking method used in the field of ATM network traffic control are presented. Also an extended cell marking method considering the user level priority is proposed. The conventional traffic monitoring schemes set the CLP bit of a cell to 1 only under the circumstance of the violation of traffic contract. It causes that the number of low level cells increases and the levels of cells are lowered regardless of the user level priority. The three level priority control method combining FCI bit with CLP bit has also been proposed. It divides CLP=0 cells into two levels. Consequently, the proposed method preserves more cells in high level than the conventional one and the real loss of high level cells can be reduced. The performance of the proposed scheme has also been analyzed by the PBS(partial buffer sharing) with two thresholds for the proposed three levels. The result shows that the PBS with two thresholds can give more efficient control than the scheme with no priority, or the PBS with one threshold.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.3A
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• pp.318-323
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• 2004

In this paper, we present a reducing power consumption of a scheduling for reuse module selection under the time constraint. Traditional high-level synthesis do not allow reuse of complex, realistic datapath component during the task of scheduling. On the other hand, the proposed scheduling of reducing power consumption is able to approach a productivity of the design the low power to reuse which given a library of user-defined datapath component and to share of resource sharing on the switching activity in a shared resource. Also, we are obtainable the optimal the scheduling result in experimental results of our approach various HLS benchmark environment using chaining and multi-cycling in the scheduling techniques.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.15 no.4
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• pp.51-60
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• 2005

The riles or intellectual property on computer systems have increasingly been exposed to such threats that they can be flowed out by internal users or outer attacks through the network. The File Outflow Monitoring System monitors file outflows at server by making the toe when users copy files on client computers into storage devices or print them, The monitoring system filters I/O Request packet by I/O Manager in kernel level if files are flowed out by copying, while it uses Win32 API hooking if printed. As a result, it has exactly made the log and monitored file outflows, which is proved through testing in Windows 2000 and XP.

• Journal of the Korea Society of Computer and Information
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• v.6 no.2
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• pp.65-69
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• 2001

Edge detection is the most important process that belongs to the first step in image recognition or vision system and can determine the efficiency valuation. The edge detection with color images is very difficult. because color images have lots of information that contain not only general information representing shape, brightness and so on but also that representing colors. In this paper, we propose architecture of universalized Color Morphological Pyramids(CMP) which is able to give effective edge detection. Image pyramid architecture is a successive image sequence whose area ratio 2$\^$-1/(ι= 1, 2, . . . ,N) after filtering and subsampling of input image. In this technique, noise removed by sequential filtering and resolution is degraded by downsampling using CMP in various color spaces. After that, new level images are constructed that apply formula using distance of neighbor vectors in close level images and detection its image.

• Fire Science and Engineering
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• v.32 no.3
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• pp.134-139
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• 2018

Extremely fine particles seriously affect people and are becoming a social problem. Conventional methods using the type of beta ray absorption are difficult to have real-time measurements and miniaturization for the acquisition of fine dust. In this paper, a light scattering method was used. The sensors were configured internally with semiconductor laser diodes for miniaturization, low cost and lightweight. The use of the FFT method makes it easier to separate fine dust according to size compared to conventional light scattering sensors. Bluetooth communication also allows the connection, monitoring and control of devices using smart phones.

• Proceedings of the Korean Information Science Society Conference
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• 2005.07a
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• pp.778-780
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• 2005

최근 가정, 자동차, 사무실등 많은 장소에서 임베디드 장치를 쉽게 찾아볼 수가 있다. 이렇듯 많은 분야에서 임베디드 장치가 사용됨에 따라 임베디드 시스템 제조업자들은 보다 빠른 시간에 많은 분야에 적용 가능한 임베디드 소프트 웨어를 개발해야 하는 어려움이 생겼다. 이러한 어려움은 소프트웨어 개발시간을 줄일 수 있도록 도와주는 개발환경의 필요성을 증가시켰다. 개발도구 중 디버깅도구는 개발시간의 대부분을 차지하는 디버깅 과정을 도움으로써 개발시간 단축이 큰 역할을 한다. 기존 디버깅도구는 모든 변수에 대한 데이터 추출을 하기 위하여 자원사용량과 처리량을 증가 시킴으로써 많은 부하를 발생시킨다. 이에 모니터링에 의한 부하를 최소화하기 위하여 변수 값을 추출하기 위한 모니터링 센서 기법과 실행시간 중 모니터링 대상을 변경하기 위한 디버깅레벨기법을 사용하여 소프트웨어의 내부 변수가 동작하면서 발생되는 오류를 검출할 수 있는 임베디드 모니터링 시스템을 설계 및 개발하였다. 하지만 실행시간 모니터링 중에 센서의 동작과정에 따르는 부하로 인하여 정확하지 않은 데이터를 추출할 수 있는 문제점이 발생되었다. 이러한 문제를 해결하기 위해 본 논문에서는 센서의 수행과정을 최소화하도록 센서 처리 구조를 변경하고 최적화된 센서 구조의 실행시간을 줄이기 위해 비트마스킹 기법을 사용한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2010.04a
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• pp.892-895
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• 2010

무선 기기의 소형화와 무선 통신 기술의 발달, 그리고 센서의 환경 정보 측정 기술 및 센서 네트워크의 확산으로 홍수, 태풍, 지진, 환경 오염, 등 재난의 피해를 줄이고자 재해 방지 시스템에 대한 연구가 활발하게 진행되고 있다. 그리고 이러한 재해는 특정한 시간에 특정 지점에만 발생하는 특징이 있으며, 이 발생 시간을 제외한 나머지 시간대에서는 정상적인 상황을 유지한다. 이와 같은 특성은 센서 네트워크 응용에서 센서의 배터리 전력 유지 및 환경 정보 획득 방법을 설계할 때, 주요한 사안으로 고려되고 있다. 이 논문에서는 센서의 전력소비를 줄이고 대기 오염에 대한 정보를 오염 발생 시간에 따라 적절히 획득하기 위하여, 대기 오염 방지 시스템에서의 센서 샘플링 주기 조정 기법을 제안한다. 제안된 기법은 대기 오염의 현재와 가까운 미래의 상태를 기반으로 센서의 샘플링 주기가 변화하는 규칙과 경계, 가중치를 설정한다. 그리고 매 샘플링 주기마다 센서 데이터 값과 이전에 저장된 오염 레벨을 고려하여 다음 샘플링 주기를 갱신한다. 이렇게 변화하는 샘플링 주기로 인해 대기 오염 감지 시스템은 측정 데이터의 정확도와 센서의 배터리 전력 소비의 균현을 적절히 유지할 수 있다. 제안된 샘플링 주기 기법은 다양한 환경 감시 응용에 활용될 수 있다.