• Proceedings of the KIEE Conference
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• 2006.10d
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• pp.261-262
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• 2006

City Train Technology that is large and complex system and consists of mechanical, electronic, electric, materials, computer, communication, civil/track etc. is very important area of railway industry, national fundamental industry. The standardization of city train system as a public transportation method and foundation of national economy is very important in order to do effective operation and to get fundamental technology, and the information system of the standards is required to operate the city train system effectively. By building data base of city train system design knowledge using computer-aided system engineering tool-Cradle, the system development issues and the design solutions are used by all engaged persons, and are managed by modeling and documentation. And this system will support architecture design consistently and effectively by applying this system to formalize early development process, to system requirements and configuration management, to system interface analysis and management and to system behavior analysis etc.. This study is for construction of data base of system design knowledge through making data base of many kinds of standards using CASE tool based on System Engineering Process, and introduces a model to support concurrent engineering for all engineers involved in system development allowing access to standard DB through Web from anywhere and at anytime.

• Proceedings of the KIEE Conference
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• 2006.10d
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• pp.259-260
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• 2006

City Train Technology that is large and complex system and consists of mechanical, electronic, electric, materials, computer, communication, civil/track etc. is very important area of railway industry, national fundamental industry. The standardization of city train system as a public transportation method and foundation of national economy is very important in order to do effective operation and to get fundamental technology, and the information system of the standards is required to operate the city train system effectively. By building data base of city train system design knowledge using computer-aided system engineering tool-Cradle, the system development issues and the design solutions are used by all engaged persons, and are managed by modeling and documentation. And this system will support architecture design consistently and effectively by applying this system to formalize early development process, to system requirements and configuration management, to system interface analysis and management and to system behavior analysis etc.. This study is for construction of data base of system design knowledge through making data base of many kinds of standards using CASE tool based on System Engineering Process, and introduces a model to support concurrent engineering for all engineers involved in system development allowing access to standard DB through Web from anywhere and at anytime.

• Earthquakes and Structures
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• v.5 no.5
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• pp.589-605
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• 2013

The effect of dead loads on dynamic responses of a uniform elastic beam subjected to moving loads is examined by means of a governing equation which takes into account initial bending stresses due to dead loads. First, the governing equation of beams which includes the effect of dead loads is briefly presented from the author's paper (1990, 1991, 2010). The effect of dead loads is considered by a strain energy produced by conservative initial stresses caused by the dead loads. Second, the effect of dead loads on dynamical responses produced by moving loads in simply supported beams is confirmed by the results of numerical computations using the Galerkin method and Wilson-${\theta}$ method. It is shown that the dynamical responses by moving loads are decreased remarkably on a heavyweight beam when the effect of dead loads is included. Third, an approximate solution of dynamic deflections including the effect of dead loads for a uniform beam subjected to moving loads is presented in a closed-form for the case without the additional mass due to moving loads. The proposed solution shows a good agreement with results of numerical computations with the Galerkin method and Wilson-${\theta}$ method. Finally it is clarified that the effect of dead loads on elastic uniform beams subjected to moving loads acts on the restraint of the transverse vibration for the both cases without and with the additional mass due to moving loads.

• KIEAE Journal
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• v.7 no.4
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• pp.141-146
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• 2007

It is necessary to guarantee the safety, serviceability and durability of reinforced concrete structures over their service life. However, concrete structures represent a decrease in their durability due to the effects of external environments according to the passage of time, and such degradation in durability can cause structural degradation in materials. In concrete structures, some degradations in durability increase the corrosion of embedded rebars and also decrease the structural performance of materials. Thus, the structural condition assessment of RC materials damaged by corrosion of rebars becomes an important factor that judges needs to apply restoration. In order to detect the damage of reinforced concrete structures, a visual inspection, a nondestructive evaluation method(NDE) and a specific loading test have been employed. However, obscurities for visual inspection and inaccessible members raise difficulty in evaluating structure condition. For these reasons, detection of location and quantification of the damage in structures via structural response have been one of the very important topics in system identification research. The main objective of this project is to develope a methodologies for the damage identification via static responses of the members damaged by durability. Six reinforced concrete beams with variables of corrosion position and corrosion width were fabricated and the damage detections of corroded RC beams were performed by the optimization and the conjugate beam methods using static deflection. In results it is proved that the conjugate beam method could predict the damage of RC members practically.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.1051-1059
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• 2008

In the development process of an ECU (Electrical Control Unit), numerous tests are necessary to evaluate the performance and control algorithm. The vehicle based test is expensive and requires long time. Also, it is difficult to guarantee the safety of the test driver. To overcome the various problems faced in the development process, the ECU test has been done using HIL (Hardware In the Loop). The HIL environment has the actual hardware including an ECU and a virtual vehicle model. In this paper, the test platform environment is devloped for the AWS ECU black box test. The test platform is built on HIL (Hardware In the Loop) architecture. Using the developed test platform, the control algorithm of the AWS ECU can be evaluated under the virtual driving condition of the bi-modal tram. Driving conditions, such as a front steering angle and vehicle velocity, are defined through the PC (Personal Computer) input. Input signals are transformed to electrical signals in the PC. These signals become the input conditions of the AWS ECU. The AWS ECU is stimulated by arbitory input conditons, and responses of the system are observed.

• Korean Journal of Environment and Ecology
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• v.21 no.2
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• pp.120-125
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• 2007

The purpose of this study was to provide basic data for developing the practical park management. For this, satisfaction degree, satisfaction factors and estimated model by satisfaction variables of visitors were analyzed through a questionnaire survey in Hallasan National Park, Korea. In the evaluation process of the satisfaction, it was found out variables of 'uncleanness of sanitation facility', 'lack of convenience and information facility' was more unsatisfactory than any other variable. The biggest satisfaction factor through factor analysis was 'usual user management factor' accounting for 45.8% of all. Estimated models of satisfaction by multiple regression analysis are showed in the order of 'lack of sanitation', 'littering problem', and 'traffic safety'.

• Korean Journal of Environment and Ecology
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• v.19 no.2
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• pp.139-143
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• 2005

The purpose of this study was to provide basic data for developing effective park management. For this, satisfaction factors and estimated model by satisfaction variables of user were analyzed through a questionnaire survey in Woraksan National Park, Korea. In the evaluation of the satisfaction, variables of the 'fee', 'lack and cleanness of facility', 'exorbitant pay', 'littering problem' were more unsatisfied than any other variables. Satisfaction factors by Factor Analysis were loaded with 'usual management'. In estimated model of satisfaction by Multiple Regression Analysis order of 'safety for recreation activities', 'parking problem', 'littering problem' were shown.

• Journal of the Korea Institute of Military Science and Technology
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• v.19 no.3
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• pp.395-403
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• 2016

A cylinder-type underwater vehicle for military use that is running near the free surface at the final homing stage to hit a surface ship target is affected by wave force and moment. Since wave can affect an underwater vehicle running at the depth less than half of the modal wave length, it is important to confirm that the underwater vehicle can work well in such a situation. In this paper, wave force and moment per unit wave amplitude depending on wave frequency, wave direction, and vehicle's running depth were calculated by 3-Dimensional panel method, and the numerical results were modeled in external force terms of six degrees of freedom equations of motion. Motion simulation of the underwater vehicle running in various speed, depth, and sea state were performed.

• Journal of the Earthquake Engineering Society of Korea
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• v.7 no.4
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• pp.89-95
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• 2003

In this paper, an algorithm to locate and size damage in a complex truss structure using the time domain response is presented. Sampled response data for specific time interval is spatially expanded over the structure to obtain the mean train energy for each element of the structure. The mean strain energy for each element is, in turn, used to build a damage index that represents the ratio of the stiffness parameter of the pre-damaged to the post-damaged structure. The validity of the methodology is demonstrated using data from a numerical example of a space truss structure with simulated damage. Also in the example, the effects of noisy data on the proposed algorithm are examined by adding random noised to the response data.

• Steel and Composite Structures
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• v.19 no.2
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• pp.441-465
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• 2015

This paper presents the experimental results of flexural and compression steel members strengthened with carbon fiber reinforced polymers (CFRP) sheets. In the flexural test, the five specimens were fabricated and the test parameters were the number of CFRP ply and the ratio of partial-length bonded CFRP sheets of specimen. The CFRP sheet strengthened steel beam had failure mode: CFRP sheet rupture at the mid span of steel beams. A maximum increase of 11.3% was achieved depending on the number of CFRP sheet ply and the length of CFRP sheet. In the compression test, the nine specimens were fabricated and the main parameters were: width-thickness ratio (b/t), the number of CFRP ply, and the length of the specimen. From the tests, for short columns it was observed that two sides would typically buckle outward and the other two sides would buckle inward. Also, for long columns, overall buckling was observed. A maximum increase of 57% was achieved in axial-load capacity when 3 layers of CFRP were used to wrap HSS columns of b/t = 60 transversely.