• Broadcasting and Media Magazine
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• v.1 no.4
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• pp.12-19
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• 1996

음향과 영상 자료를 디지털화하여 데이타베이스에 저장, 색인, 검색 관리를 효과적으로 할 수 있는 시스템의 사례를 중심으로 기술하였다. 특히 시스템의 설계 및 구축에 요하는 과정과 필요요소 및 관련 사항에 대해 소개하였고, 마지막으로 설계시 고려할 중요한 사항에 대해 언급하였다.

• Journal of KIISE:Computing Practices and Letters
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• v.13 no.4
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• pp.193-204
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• 2007

As the scale of broadcasting systems gets bigger and the functionality of broadcasting devices becomes diverse, networking facilities are being incorporated within recent broadcasting devices. Although networked devices can perform many of the additional functionalities, an effective management becomes a difficult issue. Therefore, it is essential to provide an automated management system for monitoring and controlling distributed broadcasting devices across a network. SNMP (Simple Network Management System) is one of the enabling technologies that we could adopt when we build such a system. However, SNMP-based solution has its limitations. In this paper. we propose the TMS800 system, which is a metadata-based device management system on top of SNMP framework. The system is specifically designed for the management of distributed broadcasting devices. It makes it possible to monitor not only the status of devices, but also the videos in the form of still images. Remote control and real-time notification facilities are also provided.

• Journal of KIISE:Databases
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• v.32 no.4
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• pp.416-428
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• 2005

In the paper we propose an index method for XML streaming services, where a server broadcasts XML data to a lot of clients in wireless information systems. In order to control the access and tuning time of mobile clients, the proposed method constructs the XML stream through replicating partial index intermixed with parts of data. For this purpose, we propose a two-level tree structure for separating index and XML data into two parts: replicated vs. non-replicated. We analyze the performance of the proposed method with respect to access time and tuning time. With the analysis result, we derive the optimal level value.

• Annual Conference of KIPS
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• 2002.11c
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• pp.1689-1692
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• 2002

TV-Anytime은 국제 표준으로 자리잡아가고 있는 차세대 디지털 방송용 메타데이터로서 사용자가 직접 원하는 방송을 검색하고 선택하여, 선택한 멀티미디어 데이터를 저장하였다가 시간과 장소에 구애받지 않고 사용할 수 있도록 하는 것을 목표로 하고 있다. TV-Anytime은 XML 스키마로 정의되어 있으며, 방송이라는 특성상 그 크기에 있어서 대용량이다. 본 연구에서는 이러한 TV-Anytime은 XML 스키마로 정의되어 있으며, 방송이라는 특성상 그 크기에 있어서 대용량이다. 본 연구에서는 이러한 TV-Anytime의 특성에 맞는 메타데이타 관리 시스템을 제안한다. 대용량의 문제를 해결하기 위하여 데이터베이스를 사용하며, TV-Anytime 스키마를 분석하여 그에 적합한 스키마를 설계한다. XML 형식의 TV-Anytime 메타데이타에 대한 질의를 위하여 XQuery를 사용한다. 이는 데이터베이스의 저장형식에 무관하게 질의하는 것을 가능하게 만들어 주며, 디지털방송 환경에서 시스템간의 상호 운용성이 확보될 수 있다. 또한, XQuery는 정보검색 기능을 가지고 있어서 향후 컨텐트 기반 정보검색을 포함하는 등 보다 풍부한 의미를 갖는 질의를 사용할 수 있을 것이다.

• Journal of KIISE:Computer Systems and Theory
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• v.33 no.5
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• pp.282-296
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• 2006

In a wireless client server environment, data broadcasting is an efficient data dissemination method; a server broadcasts data, and some of broadcasted data are cached in a mobile client's cache to save the narrow communication bandwidth, limited resources, and data access time. A server also broadcasts invalidation reports to maintain the consistency between server data and a client's cached data. Most of existing works on the cache consistency problems simply purge the entire cache when the disconnection time is long enough to miss the certain amount(window size) of IRs. This paper presents a cache invalidation method to increase mobile clients' cache reusability in case of a long disconnection. Instead of simply dropping the entire cache regardless of its consistency, a client estimates the cost of purging all the data with the cost of selective purge. If the cost of dropping entire cache is higher, a client maintains the cache and selectively purge inconsistent data using uplink bandwidth for validation request. The simulation results show that this scheme increases the cache reusability since it effectively considers the update rates and the broadcast frequencies of cached data in estimating the cost of cache maintenance.

• Journal of KIISE:Computing Practices and Letters
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• v.8 no.5
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• pp.551-562
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• 2002

Digital TV software, receiver system for digital broadcasting, processes huge MPEG-2 TS formatted data that has variable hierarchy. Because of complexity and enormity of MPEG-2 TS, it is difficult for user to generate test data manually. Generating of test data is not only expensive and time consuming but also requires expert knowledge of MPEG-2 standard. In this paper, we implemented the tool that generates the MPEG-2 TS formatted test data for Digital TV software. Using this tool, user ran get reliable test data without extensive knowledge of MPEG-2 standard. Also, database mechanism that our tool based on supports variable hierarchy of MPEG-2 TS.

• Journal of KIISE:Databases
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• v.32 no.3
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• pp.315-325
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• 2005

In mobile computing environments, a mobile host caches the data items to use the bandwidth efficiently and improve the response time of transactions. If the data items cached in mobile host are updated in the server, the server broadcasts an invalidation report for maintaining the cache consistency of mobile hosts. However, this method has a problem that the response time of mobile transactions can be long since their commit decision is delayed until receiving the invalidation report from the server In this paper, we propose the USR-MT method for improving the response time of mobile transactions. As the UGR-MT method can make a commit decision by using the data group information before receiving the invalidation report, the response time of mobile transactions can be improved. Also our method can improve the cache's efficiency since it prevents all the contents of a cache from being invalidated in the case that the disconnection of a mobile host is longer than the broadcast period of invalidation report.

• Journal of KIISE:Databases
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• v.35 no.3
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• pp.272-285
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• 2008

In this paper, we concentrate on data allocation methods for multiple broadcast channels. When the server broadcasts data, the important issue is to let mobile clients access requested data rapidly. Previous works first sorted data by their access probabilities and allocate the sorted data to the multiple channels by partitioning them into multiple channels. However, they do not reflect the difference of access probabilities among data allocated in the same channel. This paper proposes ZGMD allocation method. ZGMD allocates data item on multiple channels so that the difference of access probability in the same channel is maximized. ZGMD allocates sorted data to each channels and applies Broadcast Disk in each channel. ZGMD requires a proper indexing scheme for the performance improvement. This is because in ZGMD method each channel got allocated both hot and cold data. As a result, the sequential search heuristic does not allow the mobile client to access hot data items quickly. The proposed index scheme is based on using dedicated index channels in order to search the data channel where the requested data is. We show that our method achieve the near-optimal performance in terms of the average access time and significantly outperforms the existing methods.

• Proceedings of the IEEK Conference
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• 2003.07d
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• pp.1511-1514
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• 2003

본 논문에서는 지능형 방송에서 내용 기반 검색 서비스에 관해 연구하였다. 이를 통해 MPEG-7 오디오/비주얼 서술자들을 이용하여 TVAF 메타데이타와 메타데이타 전송 서비스 스키마를 확장하였다. 그리고 MPEG-7 오디오 서술자를 이용한 내용 기반 검색 시 나리에 제안된 스키마를 적용하여 효용성을 증명하였다.

• Proceedings of the Korean Information Science Society Conference
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• 2004.04b
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• pp.199-201
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• 2004

디지털 방송 환경의 메타데이타 서비스 중에서도 가장 혁신적인 것이 하이라이트(highlight)메타데이타 서비스이다. 하이라이트 메타데이타를 생성하기 위해서 시각율동을 이용한 샷경계 검출 알고리즘을 사용해 스포츠 경기의 하이라이트 시간구간을 결정하고, 하이라이트 표시기에서 하이라이트를 설명하는 간단한 주제어를 부가한다. 그리고 하이라이트 템플릿을 이용해 계층구조를 생성하고 하이라이트에 부가된 하이라이트 주제어에 따라 계층 구조의 적절한 위치에 삽입하고. 하이라이트 계층구조는 MPEG-7 표준 스키마에 따라 xml로 서술한다 하이라이트 메타데이타 서비스를 받는 시청자들은 매우 짧은 시간에 이미 방영된 스포츠 경기의 중요 장면들을 모두 볼 수 있다.