• Journal of IKEEE
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• v.19 no.2
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• pp.133-141
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• 2015

The IMS is an architectural control framework for delivering IP multimedia services such as voice, video, audio and data, the IMS supports not only the mobile communication system but also the existing wired and wireless network based on IP. The network that is integrated by the IMS needs policy-based network management protocol for managing the limited network resources to provide efficient multimedia service. The IMS use additional device called PDF for efficient resource management, but the PDF only uses diameter which is one of the network management protocol such as SNMP and COPS. Many devices use various protocol to manage the limited network resources. There is an algorithm using a variety of protocols such as Diameter, COPS and SNMP to handle the resources management efficiently. We also analyze the performance using the proposed algorithm in the implemented IMS environment.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.11a
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• pp.11-14
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• 2009

기존의 반이중방식 단방향 중계 네트워크는 하나의 정보를 두 개의 시간 슬롯 동안에 보내므로 주파수 효율에서 감소가 생기게 된다. 이러한 주파수 효율의 감소를 막기 위해 제안된 양방향 중계 네트워크는 중계기에 중첩 부호화 또는 네트워크 부호화를 적용함으로써 단방향 중계 네트워크에 비해 향상된 주파수 효율을 제공한다. 한편, OFDMA 네트워크는 사용자에게 부반송파, 전력 등의 자원을 적응적으로 할당하여 네트워크의 성능 향상을 얻을 수 있다. 본 논문에서는 다중사용자 다중중계기 양방향 OFDMA 중계 네트워크를 위한 새로운 적응적 부반송파 할당 알고리듬을 제안한다. 먼저 모든 사용자 쌍에 대한 달성 합 전송속도(achievable sum-rate over all user pairs)를 최대화하기 위한 최적화 문제를 정형화한다. 시스템의 수명을 늘이고 각 사용자의 최소 전송속도를 보장하기 위해 공정성 제한을 고려한다. 그리고 이로부터 새로운 적응적 부반송파 할당 알고리듬을 제안한다. 모의실험을 통해 제안된 알고리듬이 정적 알고리듬과 그리디 알고리듬, 두 알고리듬 모두 보다 훨씬 낮은 불능확률을 얻음을 확인한다.

• Journal of KIISE:Information Networking
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• v.37 no.2
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• pp.94-98
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• 2010

In this paper, we formalize a new adaptive online price control scheme based on the Stackelberg game model. By using the hierarchical interaction strategy, control decisions in each mechanism act cooperatively and collaborate with each other to satisfy conflicting performance criteria. In addition, our dynamic online approach is practical for real network implementation. With a simulation study, the proposed scheme can adaptively adjust the network price to approximate an optimized solution under widely diverse network situations.

• Journal of Korea Multimedia Society
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• v.13 no.1
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• pp.10-16
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• 2010

As the study of ubiquitous computing environment has been very active in recent years, the senor network technology is considered to be a core technology of it. This wireless sensor network is enabled to sense and gather data of interest from its surroundings by sensor nodes applied in physical space. Each sensor node structuring the sensor network is demanded to execute the required service using limited resources. This limited usage of resources requires the sensor node to energy-efficiently perform in building wireless sensor network, which enables to extend the entire network life. This study structures a system able to monitor changing environment data on a real-time basis using a computer remotely as it energy-efficiently gathers and sends environment data of specific areas.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.2B
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• pp.143-150
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• 2009

In this paper, we propose a novel shadow clustering mechanism including a mobility estimation algorithm based on Gauss-Markov mobility model which analyses patterns of moving direction and speed of a mobile terminal respectively and a selection algorithm of the most suitable network for the requirements of mobile terminals. The proposed mechanism makes much less shadow cluster area than that of the legacy methods, and reduces unnecessary resource reservation. It is compared the proposed algorithm with traditional methods under various scenarios.

• The KIPS Transactions:PartC
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• v.13C no.7 s.110
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• pp.933-938
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• 2006

Different multimedia services over networks not only require different amounts of bandwidth but also have different Qualify of Service (QoS) requirements. For example, QoS guarantees for higher priority calls is an important issue in multimedia communication networks. In this paper, we develop an adaptive bandwidth management algorithm, which is able to provide QoS guarantees for higher priority calls while accommodating as many heterogeneous multimedia call connections as possible. Our scheme, based on reservation and bandwidth adaptation, manages bandwidth based on real time estimates of current network conditions. Simulation results indicate the superior performance of our scheme providing excellent trade off between contradictory requirements.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.12
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• pp.30-45
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• 2014

Recently, multimedia application users who demand for ubiquitous computing environment are rapidly increasing, and wireless mesh network is receiving attention as a cost-effective key technology for next generation wireless networking. When multiple flows are transmitting data at the same time in the network, routing for path selection of each flow and link resource allocation for data transmission of each flow are one of the key factors that influence to the effectiveness of the network directly. In this paper, we consider problems for path discovery and resource allocation of links at the same time and we propose an algorithm based on mathematical modeling using a technique for cross-layer optimization design in STDMA-based wireless mesh networks that can enhance transfer performance for each flow. We show by performance analysis that the proposed algorithm can enhance the throughput performance by maximally utilizing given bandwidth resources when the number of flows increase in multi-hop wireless mesh networks.

• The KIPS Transactions:PartC
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• v.10C no.7
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• pp.915-922
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• 2003

The Grid is an infrastructure to connect heterogeneous resources that are scattered over areas with high-speed network and to cooperate with each other. To support Grid applications, network resources should be managed, since the network has to be safe and reliable. The Grid Monitoring Architecture Working Group (GMAWG) of the Global Grid Forum (GGF) proposed an effective architecture to be scalable across wide-area networks and encompass a large number of heterogeneous resources. In this paper, we describe the design and implementation of Grid network monitoring system based on the GMA for practical network management. By this system, network operations center can form a management system flexibly and scalably for Grid network.

• KIISE Transactions on Computing Practices
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• v.21 no.11
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• pp.727-732
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• 2015

These days, many researchers are working on Future Internet and a new networking paradigm called Software Defined Networking draws a great attention. In this paper, we redefine Software Defined Networking as Service Defined Networking which means that packets are categorized according to types of services. By using Service Defined Networking, we are not only dealing with the way to utilize the network resources efficiently but we also propose an algorithm to minimize the waiting time for packets to be delivered. This proposed algorithm can solve the delay problem, one of the most significant problems caused by network congestion. Also, since we are adopting Service Defined Networking, network resource utilization can be improved compared to the existing network.

• Journal of The Korean Association of Information Education
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• v.5 no.3
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• pp.364-373
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• 2001

In this paper, I have designed and implemented the total management system to integrate PC and communications device operation of elementary, middle, and high school. The proposed system gives system information management, network information management, and remote management for PC and circuit management and performance analysis function for a router. For PC management, it supports system and network configuration information monitoring and current screen view of PC by remote screen capture. For network management, it provides gathering information of a line interface and analysis function such as utilization by polling. Thru total management system, system manager of teacher can have integrated operations of computerized resources in school by collecting and monitoring information of PCs and network elements.