• The Transactions of the Korea Information Processing Society
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• v.7 no.1
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• pp.181-199
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• 2000

In this paper, we implemented and tested MPOA(MutiProtocol Over ATM) standardized in ATM Forum, which provides service for various layer 3 protocols as well as legacy LAN applications over ATM networks. The functions of MPCs(MPOA Clients) and MPSs(MPOA Servers) which are the components in MPOA systems are implemented. MPCs are located at the edge device and MPOA hosts and MPSs exist in routers. The implemented MPCs have the functions such as exchances of primitives between an LEC(LAN Emulation Client) and an MPC, management and maintenance of Egress/Ingress cache, default transmission through LECs and shortcut transmission. Assuming that routing, convergence and NHRP(Next Hop Resolution Protocol) functions exist in routers, the implemented MPSs have the functions such as exchanges of primitives between an LEC and an MPC, conversion and exchanges of frames between MPOA and NHRP, and management and maintenance of Egress/Ingress cache. All of the possible scenarios are made up to test whether they run correctly. The implemented system is tested by simulation according to the scenarios.

• Smart Structures and Systems
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• v.21 no.3
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• pp.305-320
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• 2018

The second half of the 20th century was marked with a significant raise in amount of railway bridges in Austria made of reinforced concrete. Today, many of these bridges are slowly approaching the end of their envisaged service life. Current methodology of assessment and evaluation of structural condition is based on visual inspections, which, due to its subjectivity, can lead to delayed interventions, irreparable damages and additional costs. Thus, to support engineers in the process of structural evaluation and prediction of the remaining service life, the Austrian Federal Railways (${\ddot{O}}$ BB) commissioned the formation of a concept for an anticipatory life cycle management of engineering structures. The part concerning concrete bridges consisted of forming a bridge management system (BMS) in a form of a web-based analysis tool, known as the LeCIE_tool. Contrary to most BMSs, where prediction of a condition is based on Markovian models, in the LeCIE_tool, the time-dependent deterioration mechanisms of chloride- and carbonation-induced corrosion are used as the most common deterioration processes in transportation infrastructure. Hence, the main aim of this article is to describe the background of the introduced tool, with a discussion on exposure classes and crucial parameters of chloride ingress and carbonation models. Moreover, the article presents a verification of the generated analysis tool through service life prediction on a dozen of bridges of the Austrian railway network, as well as a case study with a more detailed description and implementation of the concept applied.

• Journal of the Korea Concrete Institute
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• v.15 no.1
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• pp.25-34
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• 2003

The degradation of reinforced concrete (RC) structures due to physical and chemical attacks has been a major issue in construction engineering. Deterioration of RC structures by chloride attack followed by reinforcement corrosion is one of the serious problems. An objective of this study is to develop a form of mathematical model of chloride ingress into concrete. In order to overcome some limits of the previous approaches, a chloride ingress model, consisting of chloride solution intrusion through the capillary pore and chloride ion diffusion through the pore water, was proposed. Moreover, the variability of chloride ion diffusivity due to the degree of hydration of cement, relative humidity in pore, exposure condition, and variation of chloride binding, was considered in the model. In order to verify the proposed model, the results predicted by the proposed model were compared with analysis results of Life-365, a computer program for predicting the service life of reinforced concrete structures exposed to chlorides. In conclusion, the proposed model would be promising to predict the chloride ion profile and to estimate the service life of RC structures.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.11a
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• pp.165-166
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• 2007

• Proceedings of the Korea Concrete Institute Conference
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• 2003.11a
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• pp.66-69
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• 2003

Chloride ingress into concrete followed by reinforcement corrosion and deterioration of concrete structures is a major problem for many structures under chloride attacks. It is necessary to investigate the environmental conditions of concrete structures exposed to chloride attacks. In this study, the air-borne chloride contents in domestic marine environment were investigated.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.1B
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• pp.41-51
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• 2004

Operation and maintenance (OAM) in optical burst switching (OBS) networks has not yet been addressed even though OBS has been gaining research interest in recent years. In this paper, we defined five OBS functions such as Burst Termination (BT), Burst Transmission (BTX), Burst Switching (BSW), Routing and Switching Control (RSC), and Protection and Restoration (PAR). A functional model for OBS networks and an OAM architecture are designed to meet the operational requirements. We present the first framework to realize OAM in OBS networks, including OAM activities, OAM-capable OBS nodes such as ingress edge, core, and egress edge nodes, OAM information and communication models and protocols. A number of examples of possible network failures are pointed out and the corresponding reactions to these using the proposed OAM architecture are presented.

• Magazine of the Korea Concrete Institute
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• v.10 no.6
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• pp.325-333
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• 1998

Under the seawater environment, the reinforced concrete structure is deteriorated due to physical and chemical attacks. The main deterioration mechanism is the chloride corrosion of reinforcing steel. The corrosion inhibitors have been used to protect the rebars from corrosion which are susceptible to chlorides in concrete. However, there is not clear conclusion about corrosion inhibitors yet. In this study, it is made the accelerated experiment with 3 kinds of corrosion inhibitors for various chloride ingresses. It is estimated corrosion inhibitors that inhibitors by Half-Cell Potential, corrosion area ratio and weight loss ratio. It is concluded that inhibitors are not effective to corrosion inhibition for excessive chloride ingress. However, the effect of inhibition is directly proportional ot contents of corrosion inhibitors in some chloride ingress.

• Computers and Concrete
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• v.22 no.3
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• pp.319-326
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• 2018

RC (Reinforced Concrete) members are always subjected to loading conditions and have construction joints when constructed on a big scale. Service life for RC structure exposed to chloride attack is usually estimated through chloride diffusion test in sound concrete, however the test is performed without consideration of effect of loading and joint. In the present work, chloride diffusion coefficient is measured in concrete cured for 1 year. In order to evaluate the effect of applied load, cold joint, and mineral admixtures, OPC (Ordinary Portland Cement) and 40%-replaced GGBFS (Ground Granulated Blast Furnace Slag) concrete are prepared. The diffusion test is performed under loading conditions for concrete containing cold joint. Investigating the previous test results for 91 days-cured condition and the present work, changing diffusion coefficients with applied stress are normalized considering material type and cold joint. For evaluation of service life in RC continuous beam with 2 spans, non-linear analytical model is adopted, and service life in each location is evaluated considering the effects of applied stress, cold joint, and GGBFS. From the work, varying service life is simulated under various loading conditions, and the reduced results due to cold joint and tensile zone are quantitatively evaluated. The effect of various conditions on diffusion can provide more quantitative evaluation of chloride behavior and the related service life.

• The KIPS Transactions:PartC
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• v.12C no.1 s.97
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• pp.53-62
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• 2005

The NG-SDH system requires signal synchronization to synchronize incoming ethernet signal with GFP frame. The foreign nation research completes a chipset development until now and it secures a relation technique, but it does not secure a relation technique from domestic. Therefore, in this paper, we presented with signal synchronization method of Ethernet signal through GFP frame. We knew that the synchronized method of Ethernet signal through GFP-F must apply ingress & egress buffer and GFP Idle. We understood that the synchronized method of Ethernet signal through GFP-T must apply GFP Idle and $65B{\_}PAD$, and require maximum 3-bit addition & deletion of idle. Also we showed signal synchronization realization through simulation and obtained MTIE/TDEV characteristics and peak to peak jitter in egress output.

• The KIPS Transactions:PartC
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• v.18C no.5
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• pp.339-342
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• 2011

This paper proposes a network-based mobility control scheme in wireless/mobile networks, which is based on the Locator-Identifier Separation Protocol (LISP). Compared to the existing LISP mobility scheme, the proposed scheme is featured by the following two points: 1) each LISP Tunnel Router (TR) is implemented at the first-hop access router that mobile nodes are attached to, and 2) for handover support, the LISP Routing Locator (RLOC) update operation is performed between Ingress TR and Egress TR. By numerical analysis, it is shown that the proposed scheme can reduce the handover latency much more than the other candidate schemes.