• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.8
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• pp.643-650
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• 2014

Recently, the wireless communication applications are studied in various environment by the development of short range communication system like wireless sensor networks. This paper presents the analysis of localization schemes for ship application using received signal strength. The localization schemes using received signal strength from wireless networks are classified under two methods, which are Range based method and Range free method. Range based methods estimate the location with least square estimation based on estimated distance using path-loss model. Range free methods estimated the location with the information of anchor nodes linked to target. Simulation results show the appropriate localization scheme for each cabin environments based on the empirical path-loss model in warship's internal space.

• Journal of Korea Spatial Information System Society
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• v.1 no.1 s.1
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• pp.57-67
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• 1999

Two GIS and/or OGIS issues for ITS interoperability have been proposed and reviewed with some implications to Korean setting. They are location referencing and ITS map datum. The former must support ITS communication and data sharing. Therefore, an introduction of location referencing and other related issues have been addressed along with the Oak Ridge National Lab.'s (ORNL) location referencing scheme. The latter, proposed by ORNL, is a planned network of anchor points across the nation, that could potentially serve as a positional reference for ITS application (Gottsegen, 1997). It is composed of a set of nodes and links in a standard non-plannar network at a coarse scale for the entire nation for referencing purposes. To provide case of real time traffic information and to guarantee the seamless interoperability, we do need to develop the core ITS map datum as a national infrastructure, and the location referencing scheme should also be either developed or borrowed and localized to meet the domestic needs. Some institutional issues are also addressed along with the future research agenda.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.7B
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• pp.668-676
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• 2009

Hierarchical Mobile 1Pv6(HM1Pv6) have been proposed by IETF(Internet Engineering Task Force) beginning from Mobile 1Pv6 for mobility support in IP networks, however these researches relying on client based mobility support have not been drawn attention due to excessive consumption of wireless resources and long handover delay. In this paper, we propose the Router-based Binding Update(RBU) scheme to solve problems in existing client-based mobility support schemes. The router registers location information of mobile nodes through Neighbor Discovery protocol without additional codes for the RBU scheme to a terminal operated by existing HMlPv6. By using this the RBU scheme is designed so that it can support partial nupport based mobility and reduce handover latency rather than using HMIPv6. It is analysed and compared with existing HMIPv6 to verify efficiency of the RBU scheme. As a result, the RBU scheme has outperformed existing HMIPv6 by 15% in terms of macro handover delay especially when long delay on wireless links exists.

• Journal of Information Processing Systems
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• v.8 no.4
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• pp.603-620
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• 2012

Proxy Mobile IPv6 (PMIPv6) is a network-based mobility support protocol and it does not require Mobile Nodes (MNs) to be involved in the mobility support signaling. In the case when multiple interfaces are active in an MN simultaneously, each data flow can be dynamically allocated to and redirected between different access networks to adapt to the dynamically changing network status and to balance the workload. Such a flow redistribution control is called "flow mobility". In the existing PMIPv6-based flow mobility support, although the MN's logical interface can solve the well-known problems of flow mobility in a heterogeneous network, some missing procedures, such as an MN-derived flow handover, make PMIPv6-based flow mobility incomplete. In this paper, an enhanced flow mobility support is proposed for actualizing the flow mobility support in PMIPv6. The proposed scheme is also based on the MN's logical interface, which hides the physical interfaces from the network layer and above. As new functional modules, the flow interface manager is placed at the MN's logical interface and the flow binding manager in the Local Mobility Anchor (LMA) is paired with the MN's flow interface manager. They manage the flow bindings, and select the proper access technology to send packets. In this paper, we provide the complete flow mobility procedures which begin with the following three different triggering cases: the MN's new connection/disconnection, the LMA's decision, and the MN's request. Simulation using the ns-3 network simulator is performed to verify the proposed procedures and we show the network throughput variation caused by the network offload using the proposed procedures.

• Coupled systems mechanics
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• v.11 no.5
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• pp.439-458
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• 2022

Over-coating is one of the most popular engineering practices to strengthen Reinforced Concrete (RC) structures, due to the relative quickness and ease of construction. It consists of an external coat bonded to the outer surface of the structural RC element, either by the use of chemical adhesives, mechanical anchor bolts or simply mortar injection. In contrast to these constructive advantages, the numerical estimation of the bearing capacity of the strengthened reinforced concrete element is still complicated, not only for the complexity of modelling a flexible membrane or plate attached to a quasi-rigid solid, but also for the difficulties that raise of simulating any potential delamination between both materials. For these reasons, the standard engineering calculations used in the practice remain very approximated and clumsy. In this work, we propose the formulation of a new 2D solid-layer finite element capable to link a solid body with a flexible thin layer, as it were the "skin" of the body, allowing the potential delamination between both materials. In numerical terms, this "skin" element is intended to work as a transitional region between a solid body (modelled with a classical formulation of a standard quadrilateral four-nodes element) and a flexible coat layer (modelled with cubic beam element), dealing with the incompatibility of Degrees-Of-Freedom between them (two DOF for the solid and three DOF for the beam). The aim of the solid-layer element is to simplify the mesh construction of the strengthened RC element being aware of two aspects: a) to prevent the inappropriate use of very small solid elements to simulate the coat; b) to improve the numerical estimation of the real bearing capacity of the strengthened element when the coat is attached or detached from the solid body.

• Coupled systems mechanics
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• v.12 no.6
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• pp.481-501
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• 2023

Over-coating is one of the most popular engineering practices to strengthen Reinforced Concrete (RC) structures, due to the relative quickness and ease of construction. It consists of an external coat bonded to the outer surface of the structural RC element, either by the use of chemical adhesives, mechanical anchor bolts or simply mortar injection. In contrast to these constructive advantages, the numerical estimation of the bearing capacity of the strengthened reinforced concrete element is still complicated, not only for the complexity of modelling a flexible membrane or plate attached to a quasi-rigid solid, but also for the difficulties that raise of simulating any potential delamination between both materials. For these reasons, the standard engineering calculations used in the practice remain very approximated and clumsy. In this work, we propose the formulation of a new 2D solid-layer finite element capable to link a solid body with a flexible thin layer, as it were the "skin" of the body, allowing the potential delamination between both materials. In numerical terms, this "skin" element is intended to work as a transitional region between a solid body (modelled with a classical formulation of a standard quadrilateral four-nodes element) and a flexible coat layer (modelled with cubic beam element), dealing with the incompatibility of Degrees-OfFreedom between them (two DOF for the solid and three DOF for the beam). The aim of the solid-layer element is to simplify the mesh construction of the strengthened RC element being aware of two aspects: a) to prevent the inappropriate use of very small solid elements to simulate the coat; b) to improve the numerical estimation of the real bearing capacity of the strengthened element when the coat is attached or detached from the solid body.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37B no.9
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• pp.806-813
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• 2012

In a cloud computing environment, various solutions were introduced to provide the service to users such as Infrastructure as a Service (IaaS), Platform as a Service (PaaS), Software as a Service (SaaS) and Desktop as a Service (DaaS). Nowadays, Mobile as a Service (MaaS) to provide the mobility in a cloud environment. In other words, users must have access to data and applications even when they are moving. Thus, to support the mobility to a mobile Thin-Client is the key factor. Related works to support the mobility for mobile devices were Mobile IPv6 and Proxy Mobile IPv6 which showed performance drawbacks such as packet loss during hand-over which could be very critical when collaborating with cloud computing environment. The proposed model in this paper deploys middleware and replica servers to support the data transmission among cloud and PMIPv6 domain. It supports efficient mobility during high-speed movement as well as high-density of mobile nodes in local mobility anchor. In this paper, through performance evaluation, the proposed scheme shows the cost comparison between previous PMIPv6 and verifies its significant efficiency.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.10A
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• pp.1131-1138
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• 2004

In Hierarchical Mobile Ipv6 (HMIPv6) networks, the mobility anchor point (MAP) handles binding update (BU) procedures locally to reduce signaling overhead for mobility. However, as the number of mobile nodes (MNs) handled by the MAP increases, the MAP suffers from the overhead not only to handle signaling traffic but also to Process data tunneling traffic. Therefore, it is important to control the number of MNs serviced by the MAP, in order to mitigate the burden of the MAP. We propose an adaptive load control scheme, which consists of two sub-algorithms: threshold-based admission control algorithm and session-to-mobility ratio (SMR) based replacement algorithm. When the number of MNs at a MAP reaches to the full capacity, the MAP replaces an existing MN at the MAP, whose SMR is high, with an MN that just requests binding update. The replaced MN is redirected to its home agent. We analyze the proposed load control scheme using the .Markov chain model in terms of the new MN and the ongoing MN blocking probabilities. Numerical results indicate that the above probabilities are lowered significantly compared to the threshold-based admission control alone.