• 한국통신학회논문지
• /
• 제37권1C호
• /
• pp.63-75
• /
• 2012

본 논문은 1Mbps 이하의 전술통신망 환경에서 소프트웨어 방식의 화상회의 운용방안을 연구하였다. 전술통신망 환경은 대역폭이 제한될 뿐만 아니라 불안정한 네트워크 상태로 데이터 손실과 전송지연 현상이 빈번히 발생한다. 또한 전술통신망을 기반으로 하는 지상전술지휘통제체계가 대역폭 사용의 우선권을 갖고 있기 때문에 화상회의가 사용할 수 있는 대역폭은 더욱 제한될 수밖에 없다. 본 논문에서는 이와 같은 전술통신망의 제한사항을 분석하고, 전술통신망 기반의 소프트웨어 방식 화상회의 품질향상 방안과 이를 적용한 실제 운용실험 결과를 함께 제시하였다. 손실패킷에 대한 재전송기법과 데이터 용량을 줄이기 위한 영상크기 축소를 우선적으로 적용하였다. 화상회의 운용을 위해서는 사용자 대역폭 보장이 최선의 해결방안이나 제한된 대역폭의 전술통신망에서는 영상 데이터 압축률 조정, 전송되는 영상 프레임 수 조정, 음성코덱 변경, 음성보정 데이터 사용 등을 최적화하여 화상회의 품질을 향상시킬 수 있다.

• 대한음성학회:학술대회논문집
• /
• 대한음성학회 2007년도 한국음성과학회 공동학술대회 발표논문집
• /
• pp.207-210
• /
• 2007

As the Internet is prevalent in our life, harmful contents have been increasing on the Internet, which has become a very serious problem. Among them, pornographic video is harmful as poison to our children. To prevent such an event, there are many filtering systems which are based on the keyword based methods or image based methods. The main purpose of this paper is to devise a system that classifies the pornographic videos based on the audio information. We use Mel-Cepstrum Modulation Energy (MCME) which is modulation energy calculated on the time trajectory of the Mel-Frequency cepstral coefficients (MFCC) and MFCC as the feature vector and Gaussian Mixture Model (GMM) as the classifier. With the experiments, the proposed system classified the 97.5% of pornographic data and 99.5% of non-pornographic data. We expect the proposed method can be used as a component of the more accurate classification system which uses video information and audio information simultaneously.

• 한국지능시스템학회논문지
• /
• 제17권4호
• /
• pp.519-525
• /
• 2007

최근 로봇 기술 및 응용에 대한 관심이 고조됨에 따라, 로봇의 청각기술에 대한 연구가 활발하다. 본 기술에서는 로봇 탑재용으로 인간 청각기능중 하나인 음원정위 및 추적기술에 대하여 논한다. 음원 정위 및 추적을 위하여 시청각 정보를 이용하였는데, 시각정보로는 얼굴색 기반 얼굴 탐지 정보를 이용하였으며, 양이(binaural) 기반의 음원 추정 정보가 청각 정보로서 활용되었다. 시각과 청각 정보는 Kalman 필터를 이용하여 통합하였다. 실험결과 시청각 음원 추적 기술은 일부 정보의 유실이 있을 때, 효과적으로 활용될 수 있음을 보였다.

• 한국산업정보학회논문지
• /
• 제12권1호
• /
• pp.54-60
• /
• 2007

The Digital Multimedia Broadcasting(DMB) system is developed to offer high quality multimedia content to the mobile environment. The system adopts the MPEG-4 standard for the main video, audio and other media format. For providing interactive contents, it also adopts the MPEG-4 scene description that refers to the spatio-temporal specifications and behaviors of individual objects. With more interactive contents, the scene description also needs higher bitrate. However, the bandwidth for allocating meta data, such as scene description is restrictive in the mobile environment. On one hand, the DMB terminal renders each media stream according to the scene description. Thus the binary format for scene(BIFS) stream corresponding to the scene description should be decoded and parsed in advance when presenting media data. With this reasoning, the transmission delay of the BIFS stream would cause the delay in transmitting whole audio-visual scene presentations, although the audio or video streams are encoded in very low bitrate. This paper presents the effective optimization technique in adapting the BIFS stream into the expected bitrate without any waste in bandwidth and avoiding transmission delays inthe initial scene description for interactive DMB content.

• 전자공학회논문지CI
• /
• 제40권5호
• /
• pp.289-297
• /
• 2003

음성인식 시스템과 입술독해 시스템을 결합한 하여 음향학적 잡음에 대하여 안정된 성능을 갖는 바이모달(bimodal) 시스템을 구현한다. 바이모달 시스템의 성능은 두 인식 시스템의 성능뿐만 아니라 입력 신호의 끝점검출 성능에도 크게 영향을 받는다. 본 논문에서는 음성신호와 영상신호에서 끝점을 자각 자동 검출하여 입력 음성신호로부터 음성신호에서 추정한 신호대잡음비(signal-to-noise ratio: SNR)로 두 끝점검출 결과를 선택하는 방법을 제안한다. 즉 낮은 SNR에서는 영상신호로부터 검출된 끝점을 선택하고 높은 SNR에서는 음성신호로부터 검출된 끝점을 선택함으로써 음향학적 잡음에 대하여 견실하게 끝점을 검출한다. 제안한 끝점검출 방법이 적용된 바이모달 시스템이 강한 음향학적 잡음에 대하여 만족스러운 인식성능을 나타냄을 실험견과에서 확인할 수 있다.

• Journal of Electrical Engineering and information Science
• /
• 제2권3호
• /
• pp.41-50
• /
• 1997

In this paper, we describe the design, implementation and evaluation for a multimedia conferencing system with intramedia and intermedia synchronization support between audio and video. The synchronization mechanism proposed here is capable of dynamically adapting to various network conditions thus providing an optimized QoS. In realizing the system based on this mechanism, NeVoT on Mbone is used for audio and VIC for video. Furthermore a synchromization controller is designed and realized with a unique process in supporting intermedia synchronization. Each media agents handling its media stream are modified with intramedia synchronization function. And a communicative function between media agents and synchronization controller is added as well for intermedia synchronization function. Each media agents function reports its buffering status to the synchronization control process which in turn send out optimized buffering delay value thus supporting intermedia synchronization. The realized system is configured and tested on Ethernet and ATM network where performance measurements were performed and its effective synchronization support has been assured.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2004년도 하계학술대회 논문집 D
• /
• pp.2429-2431
• /
• 2004

In this paper, we have designed a remote controlable HDR System using all embedded linux board. The system is composed of three parts - a HDR System, a PC client program for remote control and a Nameserver for registering and aquisition of the IP address. The system is built in an embedded board using a linux kernel. With the Linux the system can support networking and file system for a hard disk management In addition, the system embeds a web-server and a ftp-server for remote manipulation and file transfer. And the hardwares of the system are controlled by the linux device driver mechanism. MPEG1/2 technique is used to compress TV tuner signal and external analog video/audio signal. And compressed data is stored in a hard disk. The data stored in the system is accesable through lan or internet. And RTP protocol is used to enable the system to service live stream of instant video/audio input.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2005년도 추계종합학술대회
• /
• pp.945-948
• /
• 2005

In wireless and handheld platforms area, performance, power and cost are key metrics for product success. This is driving increasing levels of on-chip integration in state-of-the-art application processors. The purpose of this project is to optimize and design the energy-efficient embedded system that properly displays video and audio in real time. The requirements are for the media player to be capable of decoding real-time streaming video and audio with the least possible energy consumption for a variety of different clips at different resolutions. We implemented this Linux based multimedia player on Intel's PXA27x platform.

• ETRI Journal
• /
• 제35권6호
• /
• pp.960-968
• /
• 2013

To implement a cloud game service platform supporting multiple users and devices based on real-time streaming, there are many technical needs, including game screen and sound capturing, audio/video encoding in real time created by a high-performance server-generated game screen, and real-time streaming to client devices, such as low-cost PCs, smart devices, and set-top boxes. We therefore present a game service platform for the running and management of the game screen, as well as running the sound on the server, in which the captured and encoded game screen and sound separately provide client devices through real-time streaming. The proposed platform offers Web-based services that allow game play on smaller end devices without requiring the games to be installed locally.

• 제어로봇시스템학회논문지
• /
• 제11권9호
• /
• pp.816-821
• /
• 2005

The remote operation of $4\~5$ cranes for container loading/unloading at a port by one operator will dramatically improve loading/unloading efficiency through productivity increase, cost reduction, and so on. This study develops a remote crane control system for container loading/unloading yard cranes. First, a wireless video and audio system to transmit views and sounds of the working field is designed by using 3 web cameras and a microphone. Next, a RSVP-based multi-path reservation method is presented with a view to improving the quality of service in the communication network for remote control. Simulation results show that a RSVP-based multi-path reservation can enhance the reservation success rate in the TCP/IP network.