• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2008.11a
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• pp.239-242
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• 2008

지상파 DMB는 이동 환경에서 QVGA 급의 영상과 스테레오 오디오를 제공하는 방송 서비스로서 2005년 12월부터 본격적으로 서비스되고 있는데, 최근에는 DMB 환경에서 고품질의 영상과 오디오를 제공하려는 기술에 대한 연구가 이루어지고 있다. 지상파 DMB 환경에서 고품질의 영상 또는 오디오를 제공하기 위해서는 기존의 DMB 서비스에 추가적인 데이터들을 전송하는 것이 필요한데, 하나의 지상파 DMB 방송 채널에 할당되는 전송 비트율이 높지 않다는 점을 감안하면, 이러한 추가적인 데이터들을 효율적으로 전송하는 것이 서비스의 상용화 입장에서는 중요한 요소가 될 수 있다. 본 논문에서는 지상파 DMB 환경에서 멀티채널 오디오 서비스를 제공하고자 할 때, 추가적으로 전송되어야 하는 부가정보 스트림의 효율적인 전송을 위한 패킷화 방법을 제안한다. 지상파 DMB 환경에서 멀티채널 오디오 서비스를 제공하기 위한 부가정보 스트림은 일반 오디오 스트림과 마찬가지로 프레임 단위로 생성이 되며, 약 12kbps의 비트율을 가진다. 그러나, 부가정보 스트림을 지상파 DMB 환경에서 전송하기 위하여, MPEG-2 TS로 패킷화하여 전송하게 되면, 부가정보 스트림의 비트율보다 훨씬 높은 약 32kbps의 전송율을 가지게 된다. 본 연구에서는 이와 같은 문제점을 해결하기 위하여, 멀티채널 오디오 서비스를 위해 필요한 부가정보 스트림의 비트율을 분석하고, 이를 바탕으로 하나의 TS 패킷에 하나 이상의 부가정보 프레임을 포함하여 전송하는 방법을 제안한다. 제안한 방법의 성능 검증을 위해 제안한 방법에 따라 하나 이상의 부가정보 프레임을 하나의 TS 패킷에 포함하여 패킷화하는 것을 시뮬레이션하고, 그 결과를 제시하였다.

• Journal of Broadcast Engineering
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• v.8 no.3
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• pp.217-227
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• 2003

This paper describes an implementation of the slide-show functionality, which is one of the services that can be provided by the Digital Multimedia Broadcasting (DMB). While the existing analog radio broadcasting services provide audio only, DMB slide-show is the functionality that can deliver still images associated with the audio. For example, it can deliver the photographs of the singer, album cover images, or the lyrics of the song that correspond to the audio. There are two modes for the transmission of the slide-show. Firstly. the program-associated data (PAD) field within the DMB audio frame can be utilized and secondly, the slide-show data can be transmitted, after being multiplexed, with other service data as individual data stream separated from the audio. This paper describes PC-based implementations of a transmitter-side module that inserts slide-show data into the PAD area within audio bitstream and a receiver-side application module that plays the slide-show through decoding the PAD within the received audio bitstream and demonstrates their validity through experiments.

• Journal of Korea Multimedia Society
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• v.15 no.10
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• pp.1185-1195
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• 2012

In the general recording method of mobile broadcasting, all incoming broadcasting streams after recording time will be saved regardless of its content. In this case, as such that viewers do not want to record, commercial advertisement, are saved together. In order to solve these problems, the proposed method checks if the contents such as advertisements are exist in the target stream by analysing the splicing in incoming MPEG-2 TS streams and, if splicing happened, excludes incoming stream after the splicing in the recording process. In the proposed method, first the splice in the recording stream is verified using the related flags of adaptation field in the TS packet and, if judged to cause a splice, the time of splicing is to be estimated by evaluating the value of splice_countdown filed. In this way, the proposed algorithm provides the seamless recording method by estimating the time of splice and excluding the contents after the splicing. To evaluate the proposed seamless recording method, the simulation was carried out by modifying the software of the existing mobile broadcasting terminal.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.06a
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• pp.336-339
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• 2007

A new query model is required to match requirements of stream-based applications such as patient monitoring system, since traditional DBMSs are not designed to provide continuous queries over stream data. In the patient monitoring system, there are many types of biomedical signals such as blood pressure and temperature, and these signals gathered by biomedical sensors should be treated as a stream, that is an ordered set of signals. In this paper, we categorized all possible queries to be used in patient monitoring system by four types of queries. Then, we have proposed a new sliding window query model which is capable of expressing these four types of queries.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.7 no.3
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• pp.53-64
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• 1997

When we apply a synchronous stream cipher to the T1 carrier system, it can occur long consecutive 0's(or 1's) sequences in the received data. In this case, it is difficult to recover receiver clock and violates a communication protocol. This paper proposes block detection and serial detection method which suppress 0's sequences of more than k( $\geq$ 2) of the stream ciphertext in the T1 carrier system. These ZS methods keep security level and solve problems of stream synchronization.

• Journal of Korea Spatial Information System Society
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• v.11 no.2
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• pp.79-88
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• 2009

The volume of memory to store real-time data stream is varied dynamically. Continuous queries processing the data stream must manage the storage volume dynamically. In previous research, according to current volume of data a general memory manager which allocates and releases memory by a page unit is researched.However, the method frequently executes page allocation and release to store data stream. Moreover, particularly delayed queries can monopolize many of pages because the method directly allocates pages when a query has not enough memory. Focusing on the problems in memory management systems, this research proposes a memory management method which reduces the frequency of allocation and release and uniformly distributes pages for queries. The method can reduce the frequency of allocation and release through allocation based on utilization ratio of pages in each query and prevent memory monopoly through memory allocation which considers query delay.

• Journal of KIISE:Databases
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• v.33 no.3
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• pp.327-341
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• 2006

As we are getting to deal with more applications that generate streaming data such as sensor network, monitoring, and SDI (selective dissemination of information), active research is being conducted to support efficient processing of queries over streaming data. The applications on the Web environment like SDI, among others, require query processing over streaming XML data, and its investigation is very important because XML has been established as the standard for data exchange on the Web. One of the major problems with the previous systems that support query processing over streaming XML data is that they cannot deal adaptively with dynamically changing stream because they rely on static query plans. On the other hand, the stream query processing systems based on relational data model have achieved adaptiveness in query processing due to query operator routing. In this paper, we propose a system of adaptive query processing over streaming XML data in which the model of adaptive query processing over streaming relational data is applied. We compare our system with YFiiter, one of the representative systems that provide XML stream query processing capability, to show efficiency of our system.

• The Journal of the Korea Contents Association
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• v.18 no.1
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• pp.10-18
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• 2018

This paper presents a method to resynthesize logic of a programmed FPGA from a bitstream file that is a downloaded file for Xilinx FPGA (Field Programmable Gate Array). It focuses on reconfiguring the LUT (Look Up Table) logic. The bitstream data is compared and analyzed considering various situations and various input variables such as composing other logics using the same netlist or synthesizing the same logic at various positions to find a structure of the bitstream. Based on the analyzed bitstream, we construct a truth table of the LUT by implementing various logic for one LUT. The proposed algorithm extracts the logic of the LUT based on the truth table of the generated LUT and the bitstream. The algorithm determines the input and output pins used to implement the logic in the LUT. As a result, we extract a gate level logic from a bitstream file for the targeted Xillinx FPGA.

• Journal of the Korea Society of Computer and Information
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• v.27 no.10
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• pp.95-103
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• 2022

As 5G mobile communication services gradually expand in P2P (peer-to-peer) or D2D (device-to-device) applications, traffic-oriented stream control such as YouTube streaming is emerging as an important technology. In D2D communication, the type of data stream most frequently transmitted by users is a video stream, which has the characteristics of a large-capacity transport stream. In a D2D communication environment, this type of stream not only provides a cause of traffic congestion, but also degrades the quality of service between D2D User Equipments (DUEs). In this paper, we propose a Traffic-Oriented Stream Scheduling (TOSS) scheme to minimize the interruption of dynamic media streams such as video streams and to optimize streaming service quality. The proposed scheme schedules the media stream by analyzing the characteristics of the media stream and the traffic type in the bandwidth of 3.5 GHz and 28 GHz under the 5G gNB environment. We examine the performance of the proposed scheme through simulation, and the simulation results show that the proposed scheme has better performance than other comparative methods.

• Journal of Korea Spatial Information System Society
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• v.11 no.2
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• pp.89-98
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• 2009

As data stream is entered into system continuously and the memory space is limited, the data exceeding the memory size cannot be processed. In order to solve the problem, load shedding methods which drop a part of data to prevent exceeding the storage space have been researched. Generally, a traditional load shedding method uses random sampling with optimized rate according to data deviation. The method samples data not to distinguish those used in spatial query because the method uses only a random sampling with optimized rate according to data deviation. Therefore, the accuracy of query was reduced in u-GIS environment including spatial query. In this paper, we researched a new load shedding method improving accuracy of the query in u-GIS environment which runs spatial query and aspatial query simultaneously. The method uses a new sampling method that samples data having low probability used in query. Therefore proposed method improves spatial query accuracy and query processing speed as applying spatial filtering operation to sampling operator.