• Journal of Digital Convergence
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• v.12 no.2
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• pp.335-341
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• 2014

To play the networked video contents in a client's mobile device in real time, the contents should be delivered to it by the contents server with streaming technology. Generally, in a server-client based commerce model, the server is in charge of both the authentication of the paid customer and distribution of the contents. The drawback of it is that if the customers' requests go on growing rapidly, the service quality would be degraded results from the problems of overloaded server or restricted network bandwidth. On the contrary, in P2P based networks, more and more the demand for service increasing, the service quality is upgraded since a customer can act as a server. But, in the P2P based network, there are too many servers to manage, it's possible to distribute illegal contents because the P2P protocol cannot control distributed servers. Thus, it's not suitable for commercial purposes. In this paper, the dymanic group authentication scheme is proposed which is suited to P2P based applications. The proposed scheme consists of group based key generation, key update, signature generation and verification protocols. It can control the seeder's state whether the seeder is joining or leaving the network, and it can be applied to hybrid P2P based commerce model where sales transactions are covered by the index server and the contents are distributed by the P2P protocol.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.6
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• pp.91-97
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• 2021

A microserver is a type of a computing server, in which two or more CPU nodes are implemented on a separate computing board, and a plurality of computing boards are integrated on a main board. In building a cluster system, the microserver has advantages in several points such as energy efficiency, area occupied, and ease of management compared to the existing method of mounting legacy servers in multiple racks. In addition, since the microserver uses a fast interconnection network between CPU nodes, performance improvement for data transfers is expected. The proposed microserver can mount a total of 16 computing boards with 4 CPU nodes on the main board, and uses Serial-RapidIO (SRIO) as an interconnection network. In order to analyze the performance of the proposed microserver in terms of the interconnection network which is a core performance issue of the microserver, we compare and quantify the performance of commercial microservers. As a result of the test, it showed up to about 7 times higher bandwidth improvement when transmitting data using the interconnection network. In addition, with CloudSuite benchmark programs used in actual cloud computing, maximum 60% reduction in execution time was obtained compared to commercial microservers with similar CPU performance specification.

• ETRI Journal
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• v.40 no.1
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• pp.72-88
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• 2018

In the fifth generation (5G) era, the radio internet protocol capacity is expected to reach 20 Gb/s per sector, and ultralarge content traffic will travel across a faster wireless/wireline access network and packet core network. Moreover, the massive and mission-critical Internet of Things is the main differentiator of 5G services. These types of real-time and large-bandwidth-consuming services require a radio latency of less than 1 ms and an end-to-end latency of less than a few milliseconds. By distributing 5G core nodes closer to cell sites, the backhaul traffic volume and latency can be significantly reduced by having mobile devices download content immediately from a closer content server. In this paper, we propose a novel solution based on software-defined network and network function virtualization technologies in order to achieve agile management of 5G core network functionalities with a proof-of-concept implementation targeted for the PyeongChang Winter Olympics and describe the results of interoperability testing experiences between two core networks.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.3
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• pp.452-458
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• 2002

Although the reuse of the cached data for scrolling the map reduces the amount of passed data between client and server, it needs the conversions of data coordinates, selertive deletion of objects and cache compaction at client. The conversion is time intensive operation due to limited resources of mobile phones such as low computing power, small memory. Therefore, for the efficient map control in the vector map service based mobile phone, it is necessary to study the method for reducing wireless network bandwidth and for overwhelming the limited resources of mobile phone as well. This paper proposes the methods for racking pre-received spatial objects in client-server systems for mobile CIS. We also analyze the strengths and drawbacks between the reuse of cached data and transmission of raw data respectively.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.05a
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• pp.378-382
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• 2001

There are some technical problems in current internet-broadcasting. The load of server rises in proportion to user connection. And the inefficient usage of network bandwidth deteriorates quality of services and doesn't transport multimedia data in real time. To overcome above problems, multicast transport technology is applied to real-time multimedia data transport. But the reliability problem is still remained. This paper provides an efficient design of internet broadcasting server. We propose an multimedia data transport algorithm using adaptive encoding by grouping users according to similar connection environment. Performance evaluations show that the mechanism decreases the load of server and improves the quality of services.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.2C
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• pp.283-290
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• 2004

With the development of Web technologies, the demand for multimedia contents and network bandwidth is increasing explosively. In this situation, Caching, P2P and CDN are using for fast transmission with low traffic. In this research, we designed and implemented a redirection system for best replica selection where contents are distributed to multiple replicated web servers. This redirection system selects a close and least loaded replica and redirect a client's request to the replica. As a result, this system improved user-perceived performance. It is expected that this redirection system will contribute to the faster and more stable transmission of massive multimedia contents.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.05a
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• pp.201-204
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• 2002

Although the reuse of the cached data for scrolling the map reduces the amount of passed data between client and server, it needs the conversions of data coordinates, selective deletion of objects and cache compaction at client. The conversion is time intensive operation due to limited resources of mobile phones such as low computing power, small memory. Therefore, for the efficient map control in the vector map service based mobile phone, it is necessary to study the method for reducing wireless network bandwidth and for overwhelming the limited resources of mobile phone as well. This paper proposes the methods for caching pre-received spatial objects in client-server systems for mobile GIS. We also analyze the strengths and drawbacks between the reuse of cached data and transmission of raw data respectively.

• The KIPS Transactions:PartA
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• v.15A no.4
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• pp.227-238
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• 2008

Recently, as network environment has broadened, the demands on VOD have been increased. The VOD services can be categorized into two types, RVOD and NVOD. Practical VOD services adopt one of them exclusively. Since a method using only one of RVOD and NVOD is not able to deal with frequently variable demand of clients, it leads to a result of overload on a server and a waste of server bandwidth. The efficiency of the network resource usage becomes lower. Hence this paper presents a study on the protocol for efficient VOD services. We propose a new protocol appliable for the existing VOD service algorithm, analyze its performance through simulation, and developed server/client systems applying the new protocol. We propose a mode switching protocol combined with protocols used in RVOD and NVOD. The proposed protocol is not able only to control both RVOD and NVOD but also to change the mode between RVOD and NVOD. As a result of using the proposed protocol to meet frequently variable demand, server bandwidth can be used efficiently. Especially, it can be applied to the existing VOD service algorithms. Therefore, we expect that the proposed protocol in this paper will be widely used in emerging VOD markets.

• Convergence Security Journal
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• v.4 no.3
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• pp.47-55
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• 2004

Currently used to manage a whole bunch of networks is the Client/Server Network Management Technique in which a central manager system supports a number of managed ones. Unfortunately it has a big drawback: wasting network resources, most of all bandwidth, which is mainly caused by too much traffic between the central manager system and the managed ones. In a way to overcome this weak point, we have designed a new type of system, a Configuration Management System (CMS), based on code mobility which has been used in distributed network management systems. In this thesis we have compared the CMS with the currently used network management system, identified class to make Mobile Code, and analyzed the techniques of other network management systems in order to verify the validity of the new system.

• Journal of the Korea Computer Graphics Society
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• v.21 no.3
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• pp.17-26
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• 2015

In this paper, we explain a volume rendering system for client-server environment. A single GPU-equipped PC works as a server which is based on the ideas that only a few concurrent users use a volume rendering system in a small hospital. As the clients, we used Android mobile devices such as smart phones. User events are transformed to rendering requests by the client application. When the server receives a rendering request, it renders the volume using the GPU. The rendered image is compressed to JPEG or PNG format so that we can save network bandwidth and reduce transfer time. In addition, we perform an event pruning method while a user is dragging the touch to enhance latency. The server compensates the pruning by interpolating the touch positions. As the result, real-time volume rendering is possible for 5 concurrent users on single GPU-equipped commodity hardware.