• The KIPS Transactions:PartA
• /
• v.8A no.4
• /
• pp.287-292
• /
• 2001

Multimedia service systems should have efficient capacity to serve the growing clients and new data. In the general streaming services, users can endure the small amount of time delay at the beginning of service. But they want to have good quality of service. A streaming server tries to transfer video files to clients from a repository of files in real time. The server must guarantee concurrent and uninterrupted delivery of each video stream requested from clients. To achieve its purpose, many stream servers adopt multi-processors, sufficient memory, and RAID or SAN in their systems. In this paper, we propose a Linux-based parallel media streaming server. It is superior to the other systems in the storing structure, fault-tolerance, and service capacity. Since this system supports the web interlace, users can operate easily through the www. This system uses unique striping policy to distribute multimedia files into the parallel storage nodes. If a service request occurs, each storage node transmits striped files concurrently to the client. Its performance is better than the single media streaming service because of the parallel architecture.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.44 no.1
• /
• pp.10-17
• /
• 2007

Hierarchical modulation technology which can make the advanced T-DMB(terrestrial-digital multimedia broadcasting) system backward compatible with the conventional T-DMB system and provide high-rate and high-quality services is introduced in this paper. As additional data streams are embedded within the conventional data streams by the hierarchical modulation, the advanced T-DMB system can provide high-quality video service and more broadcasting service channels. In order to guarantee the quality of both the conventional and additional services powerful error correcting scheme is required. The error performance of advanced T-DMB system with hierarchical modulation is investigated and analyzed according to the various error correcting schemes in this paper.

• Journal of Convergence Society for SMB
• /
• v.6 no.3
• /
• pp.49-55
• /
• 2016

This paper proposes an adaptive video signal transmission scheme in order to ensure the QoS (Quality of Service) of user requirements. SVC (Scalable Video Coding) is an effective transmission scheme, because that can transmit video signal according to the video layer's weight. However, in previous works, those adaptive transmission systems which are considered about the various channel environments and user requirements have not been insufficiently studied. So, we propose the SVC signal transmission using inter-layer differential OVSF code allocation scheme in MC-CDMA. The proposed scheme is able to obtain each layer signal's protection order and control the sub-block of MC-CDMA by feedback information from receiver. Therefore, our proposed scheme is possible to provide the video quality for each users according to variable channel environments. The simulation results demonstrate the enhancement of proposed system in terms of BER performance.

• 한국HCI학회:학술대회논문집
• /
• 2008.02a
• /
• pp.601-606
• /
• 2008

When sharing real-time media in the ubiquitous computing environments, due to heterogeneous performance of devices, conflict to users' media service requirements might be occurred. To address the problems, there are extensive researches about media streaming QoS control schemes in the aspects of network or application. However, their deployment has met with difficulty because of critical reasons such as high development cost and system complexity. In this paper, in the level of media services, we propose a negotiation approach to offer improved quality of media services. The proposed approach Constructs video distribution group between producer and consumer services, which target to globally minimize the concession of users' quality requirements Consequently, users can be provided video services in the level of conformation to the users' expectation.

• Journal of Service Research and Studies
• /
• v.3 no.2
• /
• pp.45-52
• /
• 2013

With the development of information and communication technology, the Internet is more important in the social and economic influence rapidly, and it is no different in the field of health care. As health information on the Internet increasing, the availabilities of health information from the Internet becomes more important with health care professionals and information specialists. the quality of health information on the Internet are continually being presented without any guarantee or judge on the quality. It is needed to provide the right to use of qualified health information through Internet. HONCODE has been established and managed by HON (Health On the Net) Foundation. In this paper, Web sites of thyroid cancer Information are evaluated using HONCODE. They provide domestic medical information on the Internet. Through this, more accuracy and evaluated information could be provided on the Internet about the thyroid cancer.

• Journal of the Korea Society for Simulation
• /
• v.17 no.4
• /
• pp.89-97
• /
• 2008

In wireless personal area networks (WPANs), the successful design of channel time allocation algorithm is a key factor in guaranteeing the various quality of service (QoS) requirements for the stringent real-time constraints of multimedia services. In this paper we propose a channel time allocation algorithm for achieving a high quality transmission and high channel error tolerance of MPEG stream in the IEEE 802.15.3 high-rate wireless PANs. Our algorithm exploits the characteristics of MPEG stream. When a new MPEG stream arrives, a DEV models it by the traffic envelope and delivers the traffic envelope to the piconet coordinator (PNC) along with the channel time request. The PNC performs channel time allocation according to the envelope. Performance of the proposed scheme is investigated by simulation and analysis. Our results show that compared to conventional scheme, the proposed scheme is very effective and provides a good performance under typical channel error conditions.

• The KIPS Transactions:PartC
• /
• v.16C no.4
• /
• pp.511-520
• /
• 2009

Grid technology enables high performance computation and mass data processing by connecting geographically distributed computing resources to high-speed network. To carry on grid tasks requiring guaranteed quality of service, we need to build converged infrastructure which controls and manages network resources as well as computing resources. In this paper, we defined grid network service interface and information model to support grid network path, resource creation and reservation. In addition to resource creation and reservation messages of the existing GLIF, grid network path and notification messages were defined in the grid network service interface. We also defined related statuses and messages for two-phase resource reservation mechanism. We designed and implemented network resource management system based on the grid network information model and service interface. We experimented in resource reservation, allocation and release of network resources in grid environment with GMPLS control and transport network.

• Journal of Broadcast Engineering
• /
• v.13 no.2
• /
• pp.179-187
• /
• 2008

In this paper, we proposed the qualify metric based on SVC and the subjective quality. The proposed quality metric is for a general purpose. It means we can use it for any video sequences regardless of its temporal and spatial characteristics. The Quality of Service(QoS) is one of the important issues in heterogeneous environment which has diverse restrictions such as limited network bandwidth and limited display resolution. Scalable Video Coding(SVC) is the efficient video coding skill in heterogeneous environment. Because SVC can be adapted to various quality bitstreams using three scalabilities(spatial, temporal, and SNR) from one bitstream which has full scalability. To maximize the QoS in this environment, we should consider the subjective quality which is the viewer response. And also we should consider temporal and spatial characteristics of video sequence because the subjective quality is affected by temporal and spatial characteristics of video sequence. To verify the efficiency of the proposed method, we perform subjective assessments. The experimental results show that the proposed method has high correlation with subjective quality. The proposed method can be a decision tool of SVC birstream extraction.

• Korean Journal of Social Welfare
• /
• v.57 no.3
• /
• pp.363-387
• /
• 2005

The purpose of this study is to find out implications which can be useful for enhancement of user participation in Korean disability services from UK community care experience. In Korea, until recently dominant issue on social services always has been the shortage of service provision. But during the recent 20 years, we experienced great expansion in quantity, as though it may be not yet enough. And more recently, disabled people and organizations began to actively argue for appropriate service in quantity and quality. Now, Korean disability policy and practice are confronted to the difficult and embarrassing task how to meet the need of disabled people with limited resources, and how to response to the disabled people's voice arguing on independence and choice. This task would require somewhat deliberate reform which might be quite different from previous one. UK's experience of implementation and development of community care system would give meaningful implications to Korean disability service policy and practice related to user participation. The results of the review on user participation issues in the UK community care give several implications to Korean disability services. Above all, consumerist approach which is the key strategy adopted by UK community care change is not appropriate for Korean disability service because of largely different service environment. The second implication is about decentralization. To enable decentralization of social service leads to enhancement of user involvement avoiding a lowering of service quality, prerequisite conditions should be secured. A third is securing and making declaration on the disabled person's right to assessment and constructing public service system operated by case management process. Fourth, formalized complaints procedure should be established. Fifth, professional education which enables professionals to encourage participation of disabled people should be developed, and the role of disability movement leading disabled users to participate on their services also should be highlighted.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.14 no.1
• /
• pp.203-209
• /
• 2014

Today, Distributed denial of service (DDoS) attack present a very serious threat to the stability of the internet. The DDoS attack, which is consuming all of the computing or communication resources necessary for the service, is known very difficult to protect. The DDoS attack usually transmits heavy traffic data to networks or servers and they cannot handle the normal service requests because of running out of resources. It is very hard to prevent the DDoS attack. Therefore, an intrusion detection system on large network is need to efficient real-time detection. In this paper, we propose the detection mechanism using analysis of flow information against DDoS attacks in order to guarantee the transmission of normal traffic and prevent the flood of abnormal traffic. The OPNET simulation results show that our ideas can provide enough services in DDoS attack.