• Smart Structures and Systems
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• v.17 no.1
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• pp.149-165
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• 2016

Floods have been known to be one of the main causes of bridge collapse. Contrary to earthquakes, flood events tend to occur repeatedly and more frequently in rainfall areas; flood-induced damage and collapse account for a significant portion of disasters in many countries. Nevertheless, in contrast to extensive research on the seismic fragility analysis for civil infrastructure, relatively little attention has been devoted to the flood-related fragility. The present study proposes a novel methodology for deriving flood fragility curves for bridges. Fragility curves are generally derived by means of structural reliability analysis, and structural failure modes are defined as excessive demands of the displacement ductility of a bridge under increased water pressure resulting from debris accumulation and structural deterioration, which are known to be the primary causes of bridge failures during flood events. Since these bridge failure modes need to be analyzed through sophisticated structural analysis, flood fragility curve derivation that would require repeated finite element analyses may take a long time. To calculate the probability of flood-induced failure of bridges efficiently, in the proposed framework, the first order reliability method (FORM) is employed for reducing the required number of finite element analyses. In addition, two software packages specialized for reliability analysis and finite element analysis, FERUM (Finite Element Reliability Using MATLAB) and ABAQUS, are coupled so that they can exchange their inputs and outputs during structural reliability analysis, and a Python-based interface for FERUM and ABAQUS is newly developed to effectively coordinate the fragility analysis. The proposed framework of flood fragility analysis is applied to an actual reinforced concrete bridge in South Korea to demonstrate the detailed procedure of the approach.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.11 no.2
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• pp.12-18
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• 2015

The energy pile, used for both structural foundations and heat exchangers, brings about heat exchange with the ground formation by circulating a working fluid for heating and cooling buildings. As heat exchange occurs in the energy pile, thermal stress and strain is generated in the pile body and surrounding ground formation. In order to investigate the thermo-mechanical behavior of an energy pile, a comprehensive experimental program was conducted, monitoring the thermal stress of a cast-in place energy pile equipped with five pairs of U-type heat exchanger pipes. The heating and cooling simulation both continued for 30 days. The thermal strain in the longitudinal direction of the energy pile was monitored for a 15 operation days and another 15 days monitoring followed, without the application of heat exchange. In addition, a finite element model was developed to simulate the thermo-mechanical behavior of the energy pile. A non-linear contact model was adopted to interpret the interaction at the pile-soil interface, and thermal-induced structure mechanics was considered to handle the thermo-mechanical coupled multi-field problem.

• Archives of design research
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• v.15 no.3
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• pp.137-148
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• 2002

As human-centered design has become new paradigm in the field of design, it is also needed to apply scenario-centered design methodology in planning and design new multi-media contents. In this paper, scenario-centered design process for multimedia contnets planning ＆ design was identified through a case study of contents design of internet shopping mall "Shop 'n' Chat". The study was preceded with three kinds of scenarios during design process, which are present situation scenario to find needed contents, behavior prototype scenario to make contents concrete, and future usage scenario to design visual interface. These three stages of scenario are exampled by of finally shopping scenario between 20's girls, internet shopping scenario with using messenger, and finally navigation/interaction scenario in future internet shopping mall.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.24 no.5
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• pp.1001-1011
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• 2014

Smart Grid Devices could have security vulnerabilities that have legacy communication networks because of the fact that Smart Grid employs bi-directional communications and adopted a variety of communication interface. Consequently, it is required to build concrete response processes and to minimize the damage of the cyber attacks including security evaluation and certification methods. DCU is designed to collect meter data from numerous smart meter and send to utility's server so DCU installed between smart meter and utility's server. For this reason, If DCU compromised by attacker then attacker could use DCU to launching point for and attack on other devices. However, DCU's security evaluation and certification techniques do not suffice to be deployed in smart grid infrastructure. This work development DCU protection profile based on CC, it is expected that provide some assistance to DCU manufacturer for development of DCU security target and to DCU operator for help safety management of DCU.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.6B
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• pp.710-719
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• 2011

Shipping companies have become interested in the development of strategic ship assets management systems which are implemented for high competitiveness and business rationalization to meet the tough business environment of high oil prices and decrease in cargo. In this paper we introduce a ship assets management system that is suitable for the SAN(Ship Area Network) environment. This system is designed to execute business strategy of ship owners giving consideration to requirements of shipping stakeholders. In addition we have implemented it in a web-based ERP system (SHERP) which separates user interface and business logic. The SHERP is based on STEP and PLIB, which are international standards for data exchange of mechanical devices and parts. It also adopts a ship ontology to manage the ship information and knowledge during its life-cycle. The SHERP will be a concrete example of servitization of shipbuilding, as an information system which is used in ships and ship groups.

• Science of Emotion and Sensibility
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• v.12 no.2
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• pp.233-242
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• 2009

Recently the studies on user-centered design and form-development have become issues of general interest as the key methods for successful design. For form analysis on user it is important needs that an integrated approach of existing methods and development of expert tool for designer. Moreover analysis methods and tools have to meet with the designers needs of visual result, clear direction, concrete formative factor, user's emotional response and designer-friendly interface. This study proposed the main concepts of form analysis tool based on the user's emotional response ; integrated management, variables set-up, visual result of analysis, in-depth analysis with data mining and correlation, and reinforcement of user-centered analysis. Specific analysis tool consists of 5 functions: Project Management, Analysis Frame Set-up, Data Input-output, Basic Analysis, and In-depth Analysis. The feasibility of proposed tool was verified by a case study of mobile phone design in under-graduate class.

• Journal of KIISE:Software and Applications
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• v.33 no.6
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• pp.525-538
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• 2006

Component-Based Software Engineering (CBSE) is widely accepted as new paradigms for building applications with reusable assets. Mismatch problems occur while integrating the assets and make a burden in CBSE. Therefore, a larger-grained reuse unit than a component such as a framework is required, and it consists of relevant components, connectors and domain-specific architecture. The benefits of frameworks over components are commonly known, however, the key elements and internal structure of framework has not been clearly defined. We believe most of the framework models proposed in recent works remain at conceptual level. In this paper, we propose a practical-level framework reference model, and define key elements of frameworks. The research goal is to precisely identify concrete elements of a framework, inter-connection of components within a framework, extended notion of connectors, and tailored meaning of architecture In a framework. Hence, the proposed framework can be practically implemented in common object-oriented languages and with middleware such as lava, J2EE, CORBA Component Model (CCM) and NET.

• Structural Engineering and Mechanics
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• v.69 no.1
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• pp.11-20
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• 2019

The biaxial failure mechanism of transversally bedding concrete layers was numerically simulated using a sophisticated two-dimensional discrete element method (DEM) implemented in the particle flow code (PFC2D). This numerical modelling code was first calibrated by uniaxial compression and Brazilian testing results to ensure the conformity of the simulated numerical model's response. Secondly, 21 rectangular models with dimension of $54mm{\times}108mm$ were built. Each model contains two transversely bedding layers. The first bedding layer has low mechanical properties, less than mechanical properties of intact material, and second bedding layer has high mechanical properties, more than mechanical properties of intact material. The angle of first bedding layer, with weak mechanical properties, related to loading direction was $0^{\circ}$, $15^{\circ}$, $30^{\circ}$, $45^{\circ}$, $60^{\circ}$, $75^{\circ}$ and $90^{\circ}$ while the angle of second layer, with high mechanical properties, related to loading direction was $90^{\circ}$, $105^{\circ}$, $120^{\circ}$, $135^{\circ}$, $150^{\circ}$, $160^{\circ}$ and $180^{\circ}$. Is to be note that the angle between bedding layer was $90^{\circ}$ in all bedding configurations. Also, three different pairs of the thickness were chosen in models, i.e., 5 mm/10 mm, 10 mm/10 mm and 20 mm/10 mm. The result shows that in all configurations, shear cracks develop between the weaker bedding layers. Shear cracks angel related to normal load change from $0^{\circ}$ to $90^{\circ}$ with increment of $15^{\circ}$. Numbers of shear cracks are constant by increasing the bedding thickness. It's to be noted that in some configuration, tensile cracks develop through the intact area of material model. There is not any failure in direction of bedding plane interface with higher strength.

• Computers and Concrete
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• v.27 no.3
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• pp.199-210
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• 2021

The aim of this paper was to examine the continuous and discontinuous contact problems between the functionally graded (FG) layer pressed with a uniformly distributed load and homogeneous half plane using an analytical method and FEM. The FG layer is made of non-homogeneous material with an isotropic stress-strain law with exponentially varying properties. It is assumed that the contact at the FG layer-half plane interface is frictionless, and only the normal tractions can be transmitted along the contacted regions. The body force of the FG layer is considered in the study. The FG layer was positioned on the homogeneous half plane without any bonds. Thus, if the external load was smaller than a certain critical value, the contact between the FG layer and half plane would be continuous. However, when the external load exceeded the critical value, there was a separation between the FG layer and half plane on the finite region, as discontinuous contact. Therefore, there have been some steps taken in this study. Firstly, an analytical solution for continuous and discontinuous contact cases of the problem has been realized using the theory of elasticity and Fourier integral transform techniques. Then, the problem modeled and two-dimensional analysis was carried out by using ANSYS package program based on FEM. Numerical results for initial separation distance and contact stress distributions between the FG layer and homogeneous half plane for continuous contact case; the start and end points of separation and contact stress distributions between the FG layer and homogeneous half plane for discontinuous contact case were provided for various dimensionless quantities including material inhomogeneity, distributed load width, the shear module ratio and load factor for both methods. The results obtained using FEM were compared with the results found using analytical formulation. It was found that the results obtained from analytical formulation were in perfect agreement with the FEM study.

• Computers and Concrete
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• v.31 no.5
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• pp.385-394
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• 2023

Displacement is an important element for evaluating the stability and failure mechanism of hydraulic structures. Digital image correlation (DIC) is a useful technique to measure a three-dimensional displacement field using two cameras without any contact with test material. The objective of this study is to evaluate the behavior of stacked geotextile tubes using the DIC technique. Geotextile tubes are stacked to build a small-scale temporary dam model to exclude water from a specific area. The horizontal and vertical displacements of four stacked geotextile tubes are monitored using a dual camera system according to the upstream water level. The geotextile tubes are prepared with two different fill materials. For each dam model, the interface layers between upper and lower geotextile tubes are either unreinforced or reinforced with a cementitious binder. The displacement of stacked geotextile tubes is measured to analyze the behavior of geotextile tubes. Experimental results show that as upstream water level increases, horizontal and vertical displacements at each layer of geotextile tubes initially increase with water level, and then remain almost constant until the subsequent water level. The displacement of stacked geotextile tubes depends on the type of fill material and interfacial reinforcement with a cementitious binder. Thus, the proposed DIC technique can be effectively used to evaluate the behavior of a hydraulic structure, which consists of geotextile tubes.