• Journal of the Korea Computer Industry Society
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• v.3 no.8
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• pp.1027-1038
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• 2002

Multimedia data services have been widely developed with the recent progression of the Internet technology. Multimedia services, especially, must guarantee Quality of Service with restricted environment resources. The abrupt increase of transmission quanta, so called burst, and the number of client that access multimedia server, with limited network bandwidth will demage the quality of service and the utilization of network resource. Smoothing techniques can reduce the burst of a variable bit rate stream by transmitting data at a series of fixed rates. In this paper, we present a new smoothing algorithm using MPEG's characteristics in transmitting stored video data with VBR. The smoothing algorithm we present will be verified with assorted existing techniques in diverse environments.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.146-149
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• 2005

Confusion of network traffic is increased by increasing of internet user and large of network, Specially olded one and one communication caused loss of bandwidth because of redundant packet by increasing video conference and internet broadcasting. Thereupon multicast technique, method reducing loss of bandwith, for multimedia data transmission was proposed. This paper proposes method to solve overhead problem in the middle router through group management and capsuling with the Xcast technique added Disignated Router(DR). To solve the middle router not supporting IPv6, Xcast using tunneling technique in the IPv6 design and analyze the performance through a simulated examination.

• Proceedings of the Korean Information Science Society Conference
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• 2002.04a
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• pp.436-438
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• 2002

인터넷 기술이 반전함에 따라서 인터넷을 통한 서비스에 대한 관심도가 증가되고 있다. 특히 멀티미디어 서비스인 경우 QoS(Quality of Service)를 보장해야 만다. 그런데 제한된 대역폭 내에서 전송량이 급격히 증가하는 경우 네트워크 자원의 이용도와 서비스의 품질에 큰 영향을 준다. 이에 스무딩 기법은 가변 비트율(VBR : Variable Bit Rate)을 가진 비디오 스트림(Stream)을 전송할 때 네트워크 자원의 이용도와 서비스의 품질 저하를 막기 위해 전송률(Transmission rate)을 일정하게 유지시키는 기법으로 서버와 네트워크 사이의 중간노드에서 수행된다. 본 논문에서 스무딩 알고리즘을 프레임 단위로 저리할 경우 해당자원의 과부하가 탄생하므로 이를 개선한 스무딩 알고리즘을 제안하고, 기존 스무딩 알고리즘의 시간 복잡도와 성능을 중심으로 비교 분석하였다.

• Proceedings of the Korean Information Science Society Conference
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• 2002.10e
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• pp.481-483
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• 2002

압축한 비디오데이타를 네트워크으로 전송 시 채널이 불안정한 경우 패킷이 분실될 우려가 있다. 패킷 분실은 대부분 버스트오류로 나타난다. 본 연구에서는 디코더에서 버스트오류를 효과적으로 은닉, 처리하는 방법으로 오류 내성 비디오 인코딩 방법을 제안한다. 이를 위해 공간적 오류은닉법으로 오류 패킷 분실을 야기시키는 손실 블록을 분리하는데 효과적인 블록 인터리빙을 적용한다. 시간적 오류 은닉에 대해서는 연속적인 내부프레임 또는 프레임간에 움직임벡터의 프레임간 패리티 비트를 삽입하는 구조를 적용한다. 비디오 인코딩 단계를 거쳐 디코더에서 수신한 블록들에 대해서는 쌍선형 보간법을 적용하여 전송시 발생한 국지적 오류를 적절하게 은닉 처리한다. 본 논문에서 제안한 인코딩 방법을 전송 블록에 부가 데이터로 포함하는 것은 표준 엔코더의 복잡도에 거의 영향을 미치지 않는다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.06a
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• pp.833-836
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• 2007

Nowadays, the rapid increase of the available amount of internet and system performance has revealed urgent need a method of decryption about digital encryption for stabilization of multimedia data transmission. In this paper, we propose a method of decryption of each frame about video data. Also for advanced decryption, we propose color image decryption method through 4-bit binary of $GF(2^m)$ inverse about an each frame.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.55 no.8
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• pp.369-374
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• 2006

Due to development of internet network environments and data compression techniques, the size and amount of multimedia data has greatly increased. They are compressed before transmission or storage. Dealing with these compressed data such as video retrieval or indexing requires decompression procedure in most cases. This causes additional computations and increases the processing time. In various applications a histogram is one of the most frequently used tools. Efficiency of extracting such histograms will drop down if decompression is involved. We propose a novel scheme for extracting histograms from images that are transformed into the compressed domain by 8x8 DCT(Discrete Cosine Transform). In this scheme an averaged version of original image is obtained by a simple linear combination of DCT coefficients with the sets of coefficients we designed.

• Proceedings of the Korean Information Science Society Conference
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• 2001.04a
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• pp.178-180
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• 2001

인터넷은 가변적인 지연, 손실, 제한된 대역폭과 같은 특성을 가진다. 따라서, 인터넷상에서 전송된 비디오는 품질을 보장받지 못한다. H.261, H.263과 같은 진보된 비디오 압축 표준은 제한된 대역폭의 인터넷에서 비디오 전송을 가능하게 한다. 이러한 압축 표준들은 움직임 예측.보상기법을 사용하여 압축된 프레임들은 시간적인 연관성을 가지게 된다. 따라서, 인터넷에서의 패킷 손실은 해당 프레임에 오류를 발생시킬 뿐만 아니라, 오류는 손실되지 않은 이후의 복원된 프레임으로 전파되어 비디오의 품질을 심각하게 떨어뜨린다. 기존에 연구된 오류 전파 방지 기법에는 NEWPRED, Error Tracking(ET), Intra-refreshment가 있고, 패킷 손실 복구 기법에는 재전송 기법과 FEC등이 있다. 그러나 비디오의 전체적인 품질을 향상시키기 위해서는 오류 전파 방지와 손실 복구가 병행되어야 한다. 따라서 본 논문에서는 인터넷을 통한 대화식 비디오를 전송하는 데 있어서 품질을 향상시키기 위해 손실 자체를 복구할 수 있는 FEC기법에 기반 하면서 참조 프레임 선택(Reference Picture Selection)을 이용하여 패킷 손실에 의한 오류 전파를 방지하는 기법을 제안한다. 실험은 제안된 비디오 오류 제어 기법이 FEC기법과 RPS기법의 장점을 살리면서 단점을 서로 보완하여 비디오의 높은 품질을 유지함을 보인다.

• Journal of Internet Computing and Services
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• v.23 no.3
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• pp.1-12
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• 2022

As the performance of Unmanned Aerial Vehicles (UAVs) are improving and the prices are lowering, it is expected that the use of UAVs will continuously grow in the future. It is important to always maintain control signal and video communication to operate remote UAVs stably, especially in military UAV operations, as unexpected jamming attacks can result in fatal UAV crashes. In this paper, to improve the network reliability and low latency when supporting UAV operations, the anti-jamming performance of Second generation Anti-jam Tactical UHF Radio for NATO (SATURN) networks is analyzed and enhanced by applying Forward Error Correction (FEC) and Minimum Shift Keying (MSK) modulation as well as Hamming code based multiple transmission techniques.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.9B
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• pp.1098-1107
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• 2011

As recent integration of wire and wireless networks and the convergence of telecommunications and broadcasting, uniform and standardized by the broadcasting operators of existing stations to provide 4A(Any-time, Any-where, Any-device, Any-contents) services for the next-generation of multimedia services research is being progressed. Demand for theses next-generation multimedia services to ensure video compression coding technology, as well as mobility, ability to operation a variety of devices, characteristics and performance of user network and the status and conditiion, user preferences and context-awareness based on the technology has an interest in technical studies. In this paper, the current internet environment, SVC(Scalable Video Coding) encoded by a mixture of multicast and overlay multicast transmission technology for broadcasting services by designing and efficient multimedia broadcasting system is proposed. In addition, ACK-Aow Optimization by overlay multicast scheme existing tree-based overlay multicast, and by comparing the effectiveness of the proposed algorithm is demonstrated.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.11
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• pp.148-154
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• 2016

Video security has recently emerged as an important issue owing to CCTV video image spill accidents over the Internet. KISA recommends the use of encryption protocols for remote access through its guidelines for CCTV personal video information protection. But still, many products do not adhere to the guidelines, and those products are easily exposed to security threats, such as hacking. To solve these security vulnerabilities, this paper proposes a CCTV system that connects from remote locations, and is implemented by using secure shell (SSH) tunneling techniques. The system enhances security by transmitting encrypted data by using SSH. By using the tunneling technique, it also solves the problem of not being able to access a CCTV recorder located inside a firewall. For evaluation of the system, this paper compares various CCTV remote access schemes and security. Experimental results on the effectiveness of the system show it is possible to obtain remote access without a significant difference in transmission quality and time. Applying the method proposed in this paper, you can configure a system secure from the threats of hacking.