• Journal of Broadcast Engineering
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• v.15 no.4
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• pp.563-581
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• 2010

In this paper, we perform subjective visual quality assessments on UHD video for UHD TV services and analyze the assessment results. Demands for video services have been increased with availabilities of DTV, Internet and personal media equipments. With this trend, the demands for high definition video have also been increasing. Currently, 2K-HD ($1920{\times}1080$) video have been widely consumed over DTV, DVD, digital camcoders, security cameras and other multimedia terminals in various types, and recently digital cinema contents of 4K-UHD($3840{\times}2160$) have been popularly produced and the cameras, beam projects, display panels that support for 4K-UHD video start to come out into multimedia markets. Also it is expected that 4K-UHD service will appear soon in broadcasting and telecommunications environments. Therefore, in this paper, subjective assessments of visual quality on resolutions, color formats, frame rates and compression rates have been carried to provide basis information for standardization of signal specification of UHD video and viewing environments for future UHDTV. As the analysis on the assessments, UHD video exhibits better subjective visual quality than HD by the evaluators. Also, the 4K-UHD test sequences in YUV444 shows better subjective visual quality than the 4K-UHD test sequences in YUV422 and YUV420, but there is little perceptual difference on 4K-UHD test sequences between YUV422 and YUV420 formats. For the comparison between different frame rates, 4K-UHD test sequences of 60fps gives better subjective visual quality than those of 30fps. For bit-depth comparison, HD test sequences in 10-bit depth were little differentiated from those in 8-bit depth in subject visual quality assessment. Lastly, the larger the PSNR values of the reconstructed 4K-UHD test sequences are, the higher the subjective visual quality is. Against the viewing distances, the differences among encoded 4K-UHD test sequences were less distinguished in longer distances from the display.

• Journal of The Korean Association of Information Education
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• v.3 no.1
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• pp.22-32
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• 1999

In this paper, a von system which is based on current computer technologies is implemented. This von system organizes many personal computers in a local network into a configuration server, storage servers, and clients. To provide reliability, the data is stored using software RAID technology. Also, multimedia services are client-based for efficiency. The software components of this von system are the von configuration software, the von configuration service software, the von management software, and the von service software. Only the von service software runs in the client, while all the others run in the configuration server. The operating system on which the configuration server is run is the Windows NT such that the software executes like the UNIX-daemon process in the Windows NT service manager.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.47 no.6
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• pp.48-56
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• 2010

Recently, we need to dramatically speed up real-time video encoding and decoding on mobile devices because complexity of video CODEC is significantly increasing along with the demand for multimedia service of high-quality and high-definition videos by users. A variety of research is conducted for parallelism of video processing using newly developed multi-core platforms. In this paper, we propose a method of parallelism based on slice partition of video compression CODEC. We propose a novel concept of a parallel slice for parallelism and propose a new coding order to be adequate to the parallel slice which keeps high coding efficiency. To minimize synchronization time of multiple parallel slices, we also propose a synchronization method to determinate whether the parallel slice could be independently decoded or not. Experimental results shows that we achieved 27.5% (40.7%) speed-up by parallelism with bit-rate increase of 3.4% (2.7%) for CIF sequences (720p sequences) by implementing the proposed algorithm on the H.264/AVC.

• Journal of Korea Multimedia Society
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• v.12 no.8
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• pp.1142-1154
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• 2009

The brand new type of mobile terminal services are kept being introduced in accordance with the development of mobile communication technology. Among many kinds of mobile application services, the PoC application standard which is using instant messaging service and group calls method with the existing walkie-talkie technology has been finished as the version 1.0 after tremendously active discussion and is being continued to be confirmed as 2.0 and 2.1. The PoC Box, which is discussed for replacing the PoC client and intermediate object as a voice messaging box, is currently being introduced and the biggest issues for PoC Box technology topics include the part of saved informations' processing and effective multimedia contents' transmission in the PoC Box system. In this research, we propose that the PaC client could effectively transmit the media to the end-user by specifying the playback location or range, focusing on the contents and the methods of dynamic controlling for saved media in PoC Box. This paper deals with the way of dynamic controlling method using the RTSP which is appropriate for PoC Box and the effective method for generation, expression, processing of various multimedia contents including audio and video objects.

• Journal of Digital Convergence
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• v.10 no.6
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• pp.259-267
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• 2012

Internet telephony is an Internet service which supports voice telephone using VoIP technology on the IP-based Internet. It has some advantages in that voice telephone services can be accompanied with multimedia services such as video communication and messaging services. Recently, the introduction of smart phones has led to a growth in social networking services and thus, the research and development of Internet telephony has been actively progressed and has the potential to become a replacement for the telephone service that is currently being used. In this paper we designed and implemented an Internet telephony network system which is developed by using Asterisk and open source softwares. It is developed on the linux system and has some features such as VoIP telephony service between SIP phones, voice mail, and call recording. It also supports web-based functions such as SIP users and server system management that is implemented by Apache web server and PHP programs. Afterwards, this system will be applied as VoIP network base technology for small sized companies and organizations. It will paly a role for encouraging companies to use open source softwares.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.2
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• pp.228-238
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• 2003

We believe that existing wire solutions such as HomePNA2.0 using phone lines and HomePlug using power line and wireless solution such as HomeRF are the most promising solutions, because of its cost-effectiveness. However, MAC protocols of these solutions provide only Class of Service(CoS) using priority mechanism like HomePNA and HomePlug or consider only voice among real-time traffics like HomeRF. For these reasons, we perceive the needs of the new MAC protocol which is no new wire solution and provides guaranteed Quality of Service (QoS) for not only voice but also video and audio. In light of this, we present the design and software implementation of a new MAC protocol for Home Networks. Our evaluation results of software implementation verify that proposed MAC protocol can provide low delay, low loss, and low jitter to real-time traffic by reserving bandwidth.

• Journal of Korea Game Society
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• v.12 no.4
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• pp.13-22
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• 2012

The wide-spread use of the broadband Internet service makes the cloud computing-based gaming service possible. A game program is executed on a cloud node and its live image is fed into a remote user's display device via video streaming. The user's input is immediately transmitted and applied to the game. The minimization of the time to process remote user's input and transmit the live image back to the user and thus satisfying the requirement of instant responsiveness for gaming makes it possible. However, the cost to build its servers can be very expensive to provide high quality 3D games because a general purpose graphics system that cloud nodes are likely to have for the service supports a single 3D application at a time. Thus, the server must have a technology of 'realtime multiple rendering' to execute multiple 3D games simultaneously. This paper proposes a new architecture of 2-tier servers of clouds nodes of which one group executes multiple games and the other produces game's live images. It also performs a few experimentations to prove the feasibility of the new architecture.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.2B
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• pp.59-68
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• 2008

In order to activate the digital broadcasting in Korea, the analog broadcasting will have been closed down until 2012. Recently IPTV(Internet Protocol TV) thorough internet has been regarded as the fourth media following the terrestrial, satellite, and cable for the digital broad casting. And it has been the important medium for the communication and broadcasting system. However IP is not easy to replace the entire broadcasting system with the digital - type broadcasting system. For the digital broadcasting, we should replace all TV sets, install the settop-boxes to receive the various IP media, solve problems about time delaying when changing channels, and support communication and broadcasting consolidation service for such as PVR and Network CCTV. IPMG is the digital converter that is able to solve these problems. In this paper, I'll develop and analyze IPMG converter's performance which sends and receives both the analogue and digital broadcasting signals through various media gives the Network PVR service.

• International Journal of Computer Science & Network Security
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• v.22 no.8
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• pp.105-112
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• 2022

Innovation is considered as an implemented innovation in education - in the content, methods, techniques and forms of educational activity and personality education (methods, technologies), in the content and forms of organizing the management of the educational system, as well as in the organizational structure of educational institutions, in the means of training and education and in approaches to social services in education, distance and multimedia learning, which significantly increases the quality, efficiency and effectiveness of the educational process. The classification of currently known pedagogical technologies that are most often used in practice is shown. The basis of the innovative activity of a modern teacher is the formation of an innovative program-methodical complex in the discipline. Along with programmatic and content provision of disciplines, the use of informational tools and their didactic properties comes first. It combines technical capabilities - computer and video technology with live communication between the lecturer and the audience. In pedagogical innovation, the principles reflecting specific laws and regularities of the implementation of innovative processes are singled out. All principles are elements of a complex system of organization and management of innovative activities in the field of education and training. They closely interact with each other, which enhances the effect of each of them due to the synergistic effect. To improve innovative activities in the training of students, today computer technologies are widely used in pedagogy as a science, as well as directly in the practice of the pedagogical process. They have gained the most popularity in such activities as distance learning, online learning, assistance in the education management system, development of programs and virtual textbooks in various subjects, searching for information on the network for the educational process, computer testing of students' knowledge, creation of electronic libraries, formation of a unified scientific electronic environment, publication of virtual magazines and newspapers on pedagogical topics, teleconferences, expansion of international cooperation in the field of Internet education. The article considers computer technologies as the main building material for the entire society. In the modern world, there is a need to prepare a person for life in a multimedia environment. This process should be started as early as possible, because the child's contact with the media is present almost from the moment of his birth.

• The KIPS Transactions:PartB
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• v.12B no.6 s.102
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• pp.661-670
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• 2005

According as services that offer multimedia streams are activated on the Internet, users who use these services we increased extremely. As a result of this, the increase of network traffic was occurred. Also it caused the problems such as the discontinuous playback in case of the s#ream playback and the asynchronization between a video and an audio. To solve these problems, it needs a method that guarantee the stable playback of media streams and a method of media transfer that can interact between a service user and media. Existing related researches has achieved the synchronization through various methods, but did not shown the results of satisfaction in the aspect of interaction. In this paper, we inserted the interactive objects in each media file, designed functions that these objects can use each other's information, and solved the interaction and the synchronization between a video and an audio. Also, we solved the discontinuous playback of a stream by the insufficiency of network bandwidth through using variable buffers.