• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.20 no.8
• /
• pp.1487-1493
• /
• 2016

The susceptible, exposed, infectious, and recovered model (SEIR) is used extensively in the field of epidemiology. On the other hand, dissemination information among users through internet grows exponentially. This information spreading can be modeled as an epidemic. In this paper, we derive the mathematical model of SEIR in viral communication from the view of optimal control theory. Overall the methods based on classical calculus, In order to solve the optimal control problem, proved to be more efficient and accurate. According to Pontryagin's minimum principle (PMP) the Hamiltonian function must be optimized by the control variables at all points along the solution trajectory. We present our method based on the PMP and forward backward algorithm. In this algorithm, one should integrate forward in time for the state equations then integrate backward in time for the adjoint equations resulting from the optimality conditions. The problem is mathematically analyzed and numerically solved as well.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.25 no.5A
• /
• pp.751-762
• /
• 2000

In the forthcoming next generation highspeed networks, the provisioning of broadband mobile multimedia services is the most important issue while an efficient network management architecture, which can manage the network resources efficiently, is essential. The next generation highspeed networks will be composed of the ATMand SDH-based transport network systems and the H-based interworking systems. The management functions of these network systems are implemented various technologies, such as TMN and SNMP. In order to integrate these network resources efficiently with heterogeneous management functions, the distributed network management architecture such as TINA is most appropriate. In this pape, we propose an interworking architecture for TINA manager and TMN agent. where the TINA-based EML subnetwork management operations mapped into the related management operations of the TMN NE agent. The proposed interworking architecture is simpler than JIDM, and the processing overhead is minimized.

• Journal of KIISE:Information Networking
• /
• v.31 no.2
• /
• pp.146-157
• /
• 2004

In order to provide continuous QoS guaranteed to a mobile user, it is required to deploy some kind of mechanisms which reserves resources in advance at the locations to which the mobile user is expected to move. An important issue with regards to these mechanisms is to minimize the waste of resources caused by redundant reservations while keeping up the QoS guaranteed services to the user In this paper, we propose a wireless network domain structure which deploys a special cell, called “a gray cell”. The boundaries of two or more neighboring domains are surrounded by the gray cells, and the gray cells are supposed to belong to all of its neighboring domains. Based on this wireless domain structure, we propose a mechanism which completely removes the waste of redundant resource reservation in the wireless network domain while greatly reducing the risk of reservation disruption caused by inter-domain handover. Using simulation, it is shown that the proposed mechanism can deal with inter-domain handover as effectively as it does with intra-domain handover. It is also presented that the proposed mechanism outperforms existing mechanisms with respect to reservation disruption time and packet losses caused by handovers.

• Journal of KIISE:Information Networking
• /
• v.33 no.2
• /
• pp.139-148
• /
• 2006

Recently with the advancement of local wireless communication technologies, digital trends of audio contents and devices are paving the way for new experiences to network-based audio streaming services. In this paper, we present the Wireless Audio Sharing (WASH) technology over Bluetooth and Wireless Local Area Network (WLAN). WASH system provides an audio sharing mechanism over multiple users and also provides stereo audio streaming between Bluetooth-enabled devices and Universal Plug and Play (UPnP) media devices connected to wired/wireless LANs. To achieve these, we extended the Bluetooth audio distribution profile and combined the extended profile with the UPnP AV architecture. With the implementation of this WASH technology, we show some experimental results of the stereo audio streaming in a real environment.

• Journal of KIISE:Information Networking
• /
• v.33 no.2
• /
• pp.183-192
• /
• 2006

This paper analyzes the price-selection problem under priority-based scheduling for QoS (Quality of Service) network services, i.e., how to determine the price associated with each service level. In particular, we focus on the problems with the pricing mechanism based on equilibrium analysis. We claim that the assumptions needed to produce equilibrium nay not hold in some important environments. Specifically, (a) the individual user's impact on the system is not infinitesimal and (b) users do not always have up-to-date global system-status knowledge crucial for optimal user decisions required for equilibrium. These may make the equilibrium models inaccurate in realistic environments. We examine the accuracy of some existing equilibrium methods by using a dynamic model that we have developed for system behavior analysis. The analysis indicates that equilibrium methods fail to model accurately the system behavior in some realistic environments.

• Journal of KIISE:Information Networking
• /
• v.31 no.2
• /
• pp.131-145
• /
• 2004

Mobile IP has been designed only to maintain communications as mobile devices move from a place to a place, so it does not guarantee Quality of Service (QoS). Hierarchical MIPv6 improved QoS somewhat using Mobility Anchor Point(MAP), but QoS guarantee problem still remains. QoS in mobile IP is important to provide multimedia and real-timeapplications services in a mobile environment, and QoS is closely related to handoff delay. Therefore, handoff delay problem is actively studied as a main issue in mobile IP research area to guarantee QoS. In this paper, we suggest SNMP Information-based routing that adds keyword management method to Information-based routing in an active network in order to resolve such a problem, Suggested QoS controlled method and existing handoff method, simulations are carried out with NS-2 for performance evaluation. The results of simulations show an improvement on handoff delay, and consequently the QoS improvement.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.39B no.6
• /
• pp.414-423
• /
• 2014

The number and size of resource constituting the web page has been increasing steadily, and this circumstance leads to rapidly falling quality of web service in mobile network that offer relatively higher delay. Moreover, Improving the quality of a web services protocol is difficult to provide network function because the current network architecture has closed structure. In this paper, we suggest schemes to enhance web performance in mobile network, which are Check Coded DOM scheme and Functional JavaScript Transmission scheme, and then try to seek idea which can be provided suggested schemes as a network function using NFV(Network Function Virtualization). For the performance evaluation and analysis about the suggested schemes, we perform network simulation using SMPL library. We confirm that suggested schemes offer better performance in term of page loading time, the number of message and the amount of traffic in the network than HTTP Protocol.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.41 no.12
• /
• pp.1914-1924
• /
• 2016

In this paper, considering virtualized Evolved Packet Core(vEPC) network for 5G mobile network, we propose architecture for supporting Service Function Chaining(SFC) in 5G mobile network. Using SFC in 5G network, dynamic path configuration and providing network services based on subscriber and traffic information. SFC technology provides logical ordered set of network functions and delivers packet through providing logical path over the physical network. Based on the perspective of 5G core network in distributed manner, we design hierarchical SFC architecture to manage SFC for global path including vEPC and SGi-LAN network, and internal path between virtualized network functions in each cloud. In this paper, we define architecture and call flow for establishing data path using SFC. Finally, we design testbed architecture for real implementation based on open source software.

• Journal of KIISE:Information Networking
• /
• v.32 no.2
• /
• pp.123-133
• /
• 2005

In recent years, service discovery is one of the major technologies of home networks which head for a pervasive computing environment. However, existing service discovery techniques are difficult to understand semantics, and they only provide syntactic level service matching. To solve these problems, we have designed and developed ontology for semantic service discovery. Our ontology could enrich the amount of devices and services representations with semantics, and the relation of devices and service could be efficiently described through primitive service. For representing context information of devices, we describe attributes of device including location information, device status and etc. To determine whether the developed ontology can be applied to service discovery systems, we have implemented a semantic service discovery system by extension of the existing Jini lookup service. Also, we have evaluated our ontology with associated software environment according to some experiment scenarios, and have proved the usefulness of our ontology-based semantic service discovery system.

• Journal of KIISE:Information Networking
• /
• v.32 no.2
• /
• pp.236-243
• /
• 2005

Most of the existing legacy DSL networks, about 80 million lines world-widely, adopted ‘ATM(Asynchronous Transfer Mode) over DSL’protocol architecture for the effective interworking with the ATM-based regional backbone networks and for the effective support of native ATM-based multimedia application services. Recently, however, the regional backbone networks are moving towards Metro Ethernet networks, instead of the ATM networks, and most of the current multimedia applications are If-based, not native ATM-based. These environmental changes push the architecture of DSL networks to be accordingly changed, and the‘Ethernet over DSL’protocol architecture, instead of existing‘ATM over DSL’, is tried to be applied to the implementation of next generation DSL networks such as VDSL(Very high-rate DSL) . In this paper, we propose two different implementation models for next generation DSL networks in Metro Ethernet backbone environments, respectively EA(Ethernet-to-ATM) implementation model and RE(Ethernet-to-Ethernet) implementation model. And, a comparative analysis focused on the performance and the backward compatability with the legacy DSL networks will be presented.