• Journal of Broadcast Engineering
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• v.18 no.3
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• pp.435-444
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• 2013

ATSC terrestrial DTV system can support high data rates for HDTV(High Definition Television) service, but it suffers from significant performance degradation caused by multipath fading. Thus, it is necessary to analyze multipath fading effects in order to enhance the DTV reception performance. Generally, DTV channel profile can be obtained by auto-correlation between reference pseudo random signal and received DTV signal. However, in the ATSC terrestrial DTV system, the estimation performance of DTV channel profile may be decreased due to the VSB modulation features. In this paper, improved DTV channel profile measurement technique is analyzed and proposed.

• Journal of KIISE:Computer Systems and Theory
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• v.35 no.11
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• pp.517-526
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• 2008

As the functionality of portable devices arc being enhanced and the performance is being greatly improved, power dissipations of battery driven portable devices are being increased. So, an efficient power management for reducing their power consumption is needed. In this paper, we propose a window-based DVS algorithm for MPEG Player. The proposed algorithm maintains the recently frame information and execution time received from MPEG player in window queue and dynamically adjusts (frequency, voltage) level based on window queue information. Our algorithm can be implemented in the common multimedia player as a module. We employed well-known MPlayer for the measurement of performance. The experimental result shows that the proposed algorithm reduces energy consumption by 56% on maximal performance.

• Journal of Korea Multimedia Society
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• v.15 no.7
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• pp.870-878
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• 2012

Recently, very rapid development of computer and sensor technologies induces various kinds of user interface (UI) technologies based on user experience (UX). In this study, we investigate and develop a smart touch projector system technology on the basis of IR sensor and image processing. In the proposed system, a user can control computer by understanding the control events based on gesture of IR pen as an input device. In the IR image, we extract the movement (or gesture) of the devised pen and track it for recognizing gesture pattern. Also, to correct the error between the coordinate of input image sensor and display device (projector), we propose a coordinate correction algorithm to improve the accuracy of operation. Through this system technology as the next generation human-computer interaction, we can control the events of the equipped computer on the projected image screen without manipulating the computer directly.

• Journal of Korea Multimedia Society
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• v.3 no.4
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• pp.407-415
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• 2000

The ultimate goal of flow control in the semiconductor fabrication process, one of the most equipment-intensive and complex manufacturing process, is to reduce lead time and work in process. In this paper, we propose stand alone layout in the form of job shop using group technology to improve the Productivity and eliminate the inefficiency in FMS (flexible manufacture system). The performance of stand alone layout and in-line layout are analyzed and compared while varying number of device variable chanties. The analysis of in-line layout is obtained by examining its adoption in the memory products of semiconductor factory. The comparison is performed through simulation using ProSys; a window 95 based discrete system simulation software, as a tool for comparing performance of two proposed layouts. The comparison demonstrates that when the number of device variable change is small, in-line layout is more efficient in terms of production Quantity. However, as the number of device variable change is more than 14 times, stand alone layout prevails over in-line layout.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.6
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• pp.1236-1243
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• 2003

In this paper, we designed and implemented a practice-oriented simulation-type web courseware to learn the ‘Digital Circuits’ subject effectively. The implemented web courseware utilized multimedia elements such as graphics, animations, and voices etc. for improving understanding and interaction of learning. Also, the web courseware could be easily updated a learning information by using database built in a web server system. In result, the implemented web courseware could encourage a learner with a motive of learning and improve effects of learning. Also, a learner can widely learn because we can add various contents to database according to need. Furthermore, the web courseware could improve understanding for learning by offering feedback on the result.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.343-347
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• 2002

In this paper, we can easily update teaming information by using database built in web server system in implementation of a web courseware that a learner can effectively team the 'Digital Circuits' subject. Also, we offered multimedia elements such as graphics, animations, and voices etc. for increasing understanding and interaction of teaming and designed and implemented a simulation-type web courseware of practice-oriented. In result, it can encourage a learner with a motive of learning and increase effects of teaming. Also, a learner can learn various contents because we can add teaming contents to database according to needs. Furthermore, it can improve understanding for teaming by offering feedback on the result. In future, we need to design and implement circuits with more complex and many functions by adding circuit with function that can store.

• Journal of KIISE:Databases
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• v.31 no.4
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• pp.341-351
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• 2004

With the popularity of digital audio contents, querying and retrieving audio contents efficiently from database has become essential. In this paper, we propose a new index scheme for retrieving audio contents efficiently using audio portions that have been queried frequently. This scheme is based on the observation that users have a tendency to memorize and query a small number of audio portions. Detecting and indexing such portions enables fast retrieval and shows better performance than sequential search-based audio retrieval. Moreover, this scheme is independent of underlying retrieval system, which means this scheme can work together with any other audio retrieval system. We have implemented a prototype system and showed its performance gain through experiments.

• Journal of KIISE:Computer Systems and Theory
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• v.26 no.8
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• pp.905-917
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• 1999

멀티미디어 시스템에서 수행되는 부하 중 상당 부분은 정해진 시간에 주기적으로 수행되어 연속 매체(continuous media)를 처리하는 주기 태스크들이다. 연속 매체들을 처리하는 두 주기 태스크의 수행 요청 시간(release time)간에 인공적인 위상(phase)을 줄 경우, 전체 부하의 처리 타이밍에 영향을 주게 되며, 특히, 적절한 위상을 부여할 경우 부하가 고르게 분산된다. 부하의 고른 분산은 태스크 간섭을 줄여 지터(jitter), 종료시한 초과(deadline miss), 그리고 긴 응답 시간(response time) 등의 문제를 해소시킨다. 본 논문에서는 새로운 위상 스케줄링(phased scheduling) 알고리즘 및 알고리즘을 개발하고 평가할 수 있는 실험 환경을 제안한다. 본 논문에 제시된 알고리즘은 저자들의 선행 논문 1 에서 제시한 알고리즘의 대안이다. 새로운 알고리즘은 정확하게 최적의 위상을 찾지는 않으나 기존 알고리즘보다 빠르게 수행되며 적용 범위가 넓다.Abstract A multimedia system consists of substantial amount of continuous media workload scheduled periodically at deterministic time points. Artificial phase between the invocation times of any two continuous media tasks affects the timing of the entire workload. A proper phase configuration distributes workload uniformly over time and reduces task interference that may otherwise result in jitter, deadline miss, and long response time. The objective of this paper is to work out a phased scheduling algorithm and to evaluate its effectiveness. The algorithm in this paper is an alternative approach to our previous work 1 . It is almost as accurate as the predecessor but two of three times faster in identifying the appropriate phase vector.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.43 no.11 s.353
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• pp.19-25
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• 2006

The fast processing ability of an RTOS (Real Time Operating System) is one of important factors in determining the performance of embedded systems. With the development of multimedia and telecommunication technology, the higher level of performance environments is required. Moreover there is some difficulty in improving the performance of an RTOS which is based on a microprocessor. In this paper, we propose a hardware architecture to implement some functions of uC/OS-II as a target RTOS for the purpose of its performance improvement. The proposed architecture for uC/OS-II is implemented and analyzed with the performance comparison.

• Journal of KIISE:Databases
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• v.30 no.2
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• pp.134-144
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• 2003

Spatial relationships among objects are one of the important ingredients for expressing constraints of an image in image or multimedia retrieval systems. In this paper, we propose a unified image retrieval scheme using spatial relationships among objects and their features. The proposed scheme is especially effective in computing similarity between query image and images in the database. Also, objects and their spatial relationships are captured and annotated in XML. It could give better precision and flexibility in retrieving images from database. Finally, we have implemented a prototype system for retrieving images based on proposed technique and showed some of the experiment results.