• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.3B
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• pp.208-213
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• 2011

Since the wireless technologies based on the IP have been developed recently, a variety of mobile services has been proposed. For broadcasting services to utilize network resources efficiently, there is a need to support handover of multicast traffic in mobile networks. In this paper, we add a network function block to solve the tunnel convergence problem, and propose a new fast handover scheme to reduce handover latency for PMIPv6 networks with multicast function. With the simulation result, we show that our fast handover scheme has better performance than the draft in the IETF in the viewpoint of handover latency and multicast service disruption.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37C no.12
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• pp.1303-1309
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• 2012

In this paper, we propose a handover scheme for seamless mobile multicast service in next generation access networks. For this, we drew optimum handover scheme when applying MIP(mobile IP), FMIP(Fast MIP), HMIP(Heterogeneous MIP), PMIP(Proxy MIP) to XG-PON1. And, we analyze handover scheme for seamless mobile multicast service in XG-PON1. The prosed handover scheme remove tunnel convergence and reduces handover delay, packet delivery cost.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.11 no.4
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• pp.9-17
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• 2007

Network Mobility basic support protocol (NEMO Basic) extends the operation of Mobile IPv6 to provide uninterrupted Internet connectivity to the communicating nodes of mobile networks. The protocol uses a mobile router (MR) in the mobile network to perform prefix scope binding updates with its home agent (HA) to establish a bi-directional tunnel between the HA and MR. This solution reduces location-update signaling by making network movements transparent to the mobile nodes (MNs) behind the MR. However, delays in data delivery and higher overheads are likely to occur because of sub-optimal routing and multiple encapsulation of data packets. To manage the mobility of the mobile network, it is important to minimize packet overhead, to optimize routing, and to reduce the volume of handoff signals over the nested mobile network. This paper proposes en aggregate router-assisted route optimization (ARARO) scheme for nested mobile networks support which introduces a local anchor router in order to localize handoff and to optimize routing. With ARARO, a mobile network node (MNN) behind a MR performs route optimization with a correspondent node (CN) as the MR sends a binding update message (BU) to aggregate router (AGR) via root-MR on behalf of all active MNNs when the mobile network moves. This paper describes the new architecture and mechanisms and provides simulation results which indicate that our proposal reduces transmission delay, handoff latency and signaling overhead. To evaluate the scheme, we present the results of simulation.

• The Journal of Engineering Geology
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• v.24 no.4
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• pp.643-648
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• 2014

Understanding of fracture networks and rock mass properties during tunnel construction is extremely important for the prediction of dangers during excavation, and for deciding on appropriate excavation techniques and support. However, rapid construction process do not allow sufficient time for surveys and interpretations for spatial distributions of fractures and rock mass properties. This study introduces a new statistical approach for predicting joint distributions at foreside of current excavation face during the excavation process. The proposed methodology is based on a cumulative space diagram for joint sets. The diagram displays the cumulative spacing between adjacent joints on the vertical axis and the sequential position of each joint plotted at equally spaced intervals on the horizontal axis. According to the diagram, the degree of linearity of points representing the regularity of joint spacing; a linear trend of the points indicates that the joints are evenly spaced, with the slope of the line being directly related to the spacing. The linear points which are stepped indicates that the fracture set show clustered distribution. A clustered pattern within the linear group of points indicates a clustered joint distribution. Fractures surveyed from an excavated space can be plotted on this diagram, and the diagram can then be extended further according to the plotted diagram pattern. The extension of the diagram allows predictions about joint spacing in areas that have not yet been excavated. To test the model, we collected and analyzed data during excavation of a 10-m-long tunnel. Fractures in a 3-m zone behind the excavation face were predicted during the excavation, and the predictions were compared with observations. The methodology yielded reasonably good predictions of joint locations.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.58 no.1
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• pp.48-55
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• 2009

In order to keep safe driving conditions under road networks, there are several formations such as road structure, road surface condition, traffic occupancy and supplement of an accurate information of traffic status ahead To support safe-driving on each road formation, each formation is supplied with various information to help the driver. However, in some cases like rapid status change at local-scale geography, traffic information systems often displays insufficient information because of the lack of information correlation. In order to accurately aware the driver, all road formation must be in sync. It is important to supply accurate information to the driver because this information directly impacts the drivers on the road. This paper discusses the amber information to keep the least safety driving over road formations including tunnels and bridges. This paper also will propose the informations for safe-driving conditions, information linkage on the road and rule-base safety information, as ITS technology, being displayed for all drivers under the worst weather conditions.

• Wind and Structures
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• v.8 no.3
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• pp.163-178
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• 2005

Wind-induced mean and dynamic interference effects of tall buildings are studied in detail by a series of wind tunnel tests in this paper. Interference excitations of several types of upwind structures of different sizes in different upwind terrains are considered. Comprehensive interference characteristics are investigated by artificial neural networks and correlation analysis. Mechanism of the wakes vortex-induced resonance is discussed, too. Measured results show significant correlations exist in the distributions of the interference factors of different configurations and upwind terrains and, therefore, a series of relevant regression equations are proposed to simplify the complexity of the multi-parameter wind induced interference effects between two tall buildings.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.34-41
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• 2008

This paper concerns the development of a IT-based tunnel design system within the framework of artificial neural networks(ANNs). The system is aimed at expediting a routine cavern design works such as determination of support patterns and stability analysis of the selected support patterns. The detailed system development process and functions of sub modules are provided in this paper.

• Proceedings of the Korea Information Processing Society Conference
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• 2016.10a
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• pp.119-122
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• 2016

대표적인 네트워크 기반의 이동성 기법인 PMIPv6(Proxy Mobility IPv6)은 이동 단말에 대한 끊김 없는 서비스 지원이 가능하다. 하지만 PMIPv6 기법은 단말과 홈 에이전트 간 IP Tunnel을 생성해야 하며, 그에 따른 시그널링 비용이 발생하게 된다. 또한, 단말 이동에 따른 연속적인 서비스 지원만 고려할 뿐 이동 중 발생하는 패킷 손실은 고려하지 않는 문제점이 있다. 본 논문은 이러한 문제점을 해결하기 위해 SDN(Software Defined Networks)을 적용하였다. 데이터 플레인에서 Anchor 스위치를 선정하여 이동 전 위치의 단말로 전송되던 패킷을 이동한 위치의 단말로 Re-direction 함으로써 패킷 손실을 줄이기 위한 기법을 제안한다.

• Tunnel and Underground Space
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• v.4 no.1
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• pp.1-16
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• 1994

The study on the flow characteristics and analysis of groundwater in discontinuous rock mass is very important, since the water inflow into the underground opening during excavation induces serious stability and environmental problems. To investigate the flow through single rock joint, the effect of various aperture distribution on the groundwater flow has been analyzed. Observed through the analysis is the "channel flow", the phenomenon that the flow is dominant along the path of large aperture for given joint. The equivalent hydraulic conductivity is estimated and verified through the application of the joint network analysis for 100 joint maps generated statistically. Both the analytic aproach based on isotropic continuum premise and the joint network analysis are tested and compared analyzing the gorundwater inflow for underground openings of different sizes and varying joint density. The joint network analysis is considered better to reflect the geometric properties of joint distribution in analyzing the groundwater flow.ater flow.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.4B
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• pp.178-185
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• 2005

NEMO basic support is a solution that provides network mobility in the Internet topology. Yet, when multiple mobile networks are nested, this basic solution suffers ken pinball-routing and a severe routing overhead. Therefore, several solutions for route optimization in a nested mobile network have already been suggested by the IETF NEMO WG. However, the current paper proposes Regional Information-based Route Optimization (RIRO) in which mobile routers maintain a Nested Router List (NRL) to obtain next-hop information, and packets are transmitted with a new routing header called an RIRO Routing Header (RIRO-RH). We showed that RIRO had the minimum packet overhead that remained constant, irrespective of how deep the mobile network was nested, in comparison with two earlier proposed schemes - Reverse Routing Header (RRH) and Bi-directional tunnel between HA and Top-Level mobile router (BHT).