• The Transactions of the Korea Information Processing Society
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• v.7 no.8
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• pp.2370-2387
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• 2000

This paper proposes a new design strategy that can overcome limitations of two existing approaches, focusing on performance and scalability issues among various architectural issues which must be considered in designing workflow systems. In the proposed approach, we suggest to introduce 'delegation model' which corresponds to the high-level strategy utilizing the fundamental characteristics of mobile agents, after establishing a mobile agent-based workflow system architecture focused on performance and scalability. We point out three major issues that should be considered in this approach and propose a 3-tier mobile agent-based workflow system architecture that effectively reflects these considerations. Also, we show that the new approach can provide better performance and scalability than existing ones - approaches based on the client-server paradigm and other approaches based on mobile agent paradigm represented by DartFlow system - by evaluating performance of the proposed architecture through the GSPN simulation.

• Journal of KIISE:Computer Systems and Theory
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• v.34 no.9
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• pp.435-444
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• 2007

Caching web pages is an important part of web infrastructures. The effects of caching service are even more pronounced for wireless infrastructures due to their limited bandwidth. Medium to large-scale infrastructures deploy a cluster of servers to solve the scalability problem and hot spot problem inherent in caching. In this paper we present scheduling scheme based on cache utilization in a wireless internet proxy server cluster environment. The proposed method uses cache utilization for distributing evenly client requests to a cluster of cache servers and solving hot spot problem. We have implemented our approach and performed various experiments using publicly available traces. Experimental results on a cluster of 16 cache servers demonstrate that the proposed hashing method gives 45% to 114% Performance improvement over other widely used methods while addressing the hot spot problem.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.6
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• pp.1087-1094
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• 2023

Due to the development of technologies, such as big data, cloud, IoT, and AI, The high data throughput is required, and the importance of network flexibility and scalability is increasing. However, existing network systems are dependent on vendors and equipment, and thus have limitations in meeting the foregoing needs. Accordingly, SDN technology that can configure a software-centered flexible network is attracting attention. In particular, a load balancing method based on SDN can efficiently process massive traffic and optimize network performance. In the existing load balancing studies in SDN environment have limitation in that unnecessary traffic occurs between servers and controllers or performing load balancing only after the server reaches an overload state. In order to solve this problem, this paper proposes a method that minimizes unnecessary traffic and appropriate load balancing can be performed before the server becomes overloaded through a method of assigning weights to servers in stages according to server load.

• Journal of the Korea society of information convergence
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• v.5 no.2
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• pp.67-76
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• 2012

XML-based open protocol, XMPP users to pass messages to other users, which means that a decentralized communication network is the network infrastructure and enable it. In addition, XMPP servers using a professional server-to-server protocol to communicate with each other and decentralized social networks and collaboration framework provides an important possibility. In this paper, the features of XMPP messaging protocol is applicable to automotive telematics terminals XMPP-based platform design, and presence of two-way communication point for the problem, point-to-point session setup issues, security issues, compatibility issues, and to solve the scalability problem XMPP-based messaging system was implemented.

• Journal of the Korea Convergence Society
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• v.5 no.4
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• pp.93-99
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• 2014

Cloud computing refers to borrow IT resources as needed by leveraging Internet technology and pay as much as you used by supporting real-time scalability depending on the service load. Virtualization which is the main technology of cloud computing is a technology that server, storage and hardware are regarded as not separate system but one system area and are allocated as needed. However, the security mechanisms provided by virtualized environments are difficult to cope with the traditional security mechanisms, having basic levels of visibility, control and audit function, on which the server is designed to monitor the traffic between the servers. In this paper, the security vulnerabilities of virtualization are analysed in the cloud computing environment and cloud virtualization security recommendations are proposed.

• ETRI Journal
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• v.28 no.4
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• pp.411-424
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• 2006

This paper presents a multimedia streaming platform for efficiently transmitting MPEG-4 content over IP networks. The platform includes an MPEG-4 compliant streaming server and client, supporting object-based representation of multimedia scenes, interactivity, and advanced encoding profiles defined by the ISO standard. For scalability purposes, we employ an application-layer multicast scheme for media transmission using overlay networks. The overlay network, governed by the central entity of the network distribution manager, is dynamically deployed according to a set of pre-defined criteria. The overlay network supports both broadcast delivery and video-on-demand content. The multimedia streaming platform is standards-compliant and utilizes widespread multimedia protocols such as MPEG-4, real-time transport protocol, real-time transport control protocol, and real-time streaming protocol. The design of the overlay network was architected with the goal of transparency to both the streaming server and the client. As a result, many commercial implementations that use industry-standard protocols can be plugged into the architecture relatively painlessly and can enjoy the benefits of the platform.

• The KIPS Transactions:PartC
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• v.9C no.3
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• pp.421-430
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• 2002

In this paper, we propose the integrated management system for computing resource such as personal computers, the interface of router, and server equipment. IRMS defines and analyzes the performance factors for system such as pc and router, also it manages assets for server equipment. Manager can make use of data for understanding conditions whether system is normal or not. We suggest a hierarchical integrated management architecture for resolving problems of scalability and managing efficiency in large domain networks.

• Journal of Communications and Networks
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• v.9 no.4
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• pp.457-465
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• 2007

Native information provider(IP) anycast suffers from routing scalability issues and the lack of stateful communication support. For this reason, we propose architecture for scalable and transparent anycast services(ASTAS), a proxy-based architecture that provides support for stateful anycast communications, while retaining the transparency offered by native anycast. Dynamic resource assignment for each initiated session guarantees that a connection is established with the most suitable target server, based on network and server conditions. Traffic engineering in the overlay can be realized in an effective way due to the dissemination of aggregated state information in the anycast overlay. To minimize the total deployment cost for ASTAS architectures, we propose optimized proxy placement and path finding heuristics based on look-ahead information gathered in network nodes. Contrary to a regular integer linear program(ILP) formulation, these heuristics allow to optimize proxy placement in large networks. A use case on a European reference network illustrates that lower proxy costs enable proxy deployment closer to the end-users, resulting in a reduced network load.

• The KIPS Transactions:PartA
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• v.14A no.1 s.105
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• pp.15-24
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• 2007

As a single video server exposes its limitation in scalability, capability, fault-tolerance, and cost-efficiency, solutions of this limitation emerge. However, these solutions have their own problems that will be discussed in this paper. To solve these problems and exploit various video silvers, we designed a parallel multimedia system architecture that supported a content-aware routing to heterogeneous personal computer (PC), operating system (OS), video servers through a HTTP-level redirection. We also developed a prototype, added different video servers into the prototype, and measured its overheads.

• Proceedings of the Korea Information Processing Society Conference
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• 2002.04b
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• pp.1483-1486
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• 2002

Multicast protocols are efficient methods of group communication, but they do not support the various transmission protocol services like a reliability guarantee, FTP, or Telnet that TCPs do. The purpose of this dissertation is to find a method to utilize sewer routers to form multicasts that can simultaneously transport multicast packets and TCP packets. For multicast network scalability and error recovery the existing SRM method has been used. Three packets per TCP transmission control window size are used for transport and an ACK is used for flow control. A CBR and a SRM is used for UDP traffic control. Divided on whether a UDP multicast packet and TCP unicast packet is used simultaneously or only a UDP multicast packet transport is used, the multicast receiver with the longest delay is measured on the number of packets and its data receiving rate. It can be seen that the UDP packet and the TCP's IP packet can be simultaneously used in a server router.