• Journal of the Korea institute for structural maintenance and inspection
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• v.3 no.1
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• pp.157-162
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• 1999

KS-code(KS B 0896) for nondestructive ultrasonic testing judge the quality level by ratio of flaw size to plate thickness only. But stress distributions using finite element analysis show that location of the flaws are more important than the flaw size. So, KS-code should take into account of flaw location for judging the quality level of welded steel structures.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.181-186
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• 2003

There are many uncertainties in structural failures or structures, so probabilistic failure cause assessment should be performed in order to consider the uncertainties. However, in many cases of forensic engineering, the failure cause assessments are performed by deterministic approach though number of uncertainties are existed in the failures or structures. Thus, deterministic approach may have possibility for leading to unreasonable and unrealistic failure cause assessment due to ignorance of the uncertainties. Therefore, probabilistic approach is needed to complement the shortcoming of deterministic approach and to perform the more reasonable and realistic failure cause assessment. In this study, reliability-based failure cause assessment (reliability based forensic engineering) is performed, which can incorporate uncertainties in failures and structures. For more practical application, the modified ETA technique is proposed, which automatically generates the defected structural model, performs structural analysis and reliability analysis, and calculates the failure probabilities of the failure events and the occurrence probabilities of the failure scenarios. Also, for more precise reliability analysis, uncertainties are estimated more reasonably by using bayesian approach based on the experimental laboratory testing data in forensic report.

• Smart Structures and Systems
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• v.12 no.3_4
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• pp.363-379
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• 2013

Dynamic displacement of structures is an important index for in-service structural condition and behavior assessment, but accurate measurement of structural displacement for large-scale civil structures such as long-span bridges still remains as a challenging task. In this paper, a vision-based dynamic displacement measurement system with the use of digital image processing technology is developed, which is featured by its distinctive characteristics in non-contact, long-distance, and high-precision structural displacement measurement. The hardware of this system is mainly composed of a high-resolution industrial CCD (charge-coupled-device) digital camera and an extended-range zoom lens. Through continuously tracing and identifying a target on the structure, the structural displacement is derived through cross-correlation analysis between the predefined pattern and the captured digital images with the aid of a pattern matching algorithm. To validate the developed system, MTS tests of sinusoidal motions under different vibration frequencies and amplitudes and shaking table tests with different excitations (the El-Centro earthquake wave and a sinusoidal motion) are carried out. Additionally, in-situ verification experiments are performed to measure the mid-span vertical displacement of the suspension Tsing Ma Bridge in the operational condition and the cable-stayed Stonecutters Bridge during loading tests. The obtained results show that the developed system exhibits an excellent capability in real-time measurement of structural displacement and can serve as a good complement to the traditional sensors.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.3
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• pp.1467-1473
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• 2013

In construction project, it is important to exchange and share the digital information generated by their own professional softwares. So this paper analyzed the information delivery requirements of steel structure according the structural design stages using IDM methodology. For schematic design stage and detailed design stage, the structural design information to share in each design stages is abstracted by defining the PM, ER, and FP. The new ERs and FPs are proposed by defining the new property sets(Psets), suchlike bolt gauge line, weld, scallop, and cope, to complement the structural design information of $IFC2{\times}3$. Finally, the reasonability of the proposed new ERs, FPs are verified by applying them to represent the standard steel connection sample in detailed design stage. As a result, the structural design information of standard steel connection could be stored and managed sufficiently by using the proposed new ERs and FPs.

• Journal of the Korea institute for structural maintenance and inspection
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• v.16 no.1
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• pp.78-88
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• 2012

Although structural concrete is well known for its good economic efficiency, it has limits of structural performance due to the low tensile strength, for which new structural members utilizing various concrete composite materials have been developed. Steel Fiber-Reinforced Concrete(SFRC) has great tensile strength, which is the one of the excellent composite material to complement the weakness of concrete, and it is also considered as a good alternative to prevent the explosive failure of high strength concrete under fire. Also, prestressed concrete members are of great advantages to long span structures and have greater shear strength compared to conventional reinforced concrete members. In this research, thus, a total of 22 direct shear test specimens were fabricated and tested to understand the shear behavior of Steel Fiber-Reinforced Prestressed Concrete(SFR-PSC) members, in which SFRC members combined with prestressing method. Based on the test results, the constitutive equations of shear behavior at crack interfaces were proposed, which provided good estimation on the shear behavior of the SFR-PSC direct shear test specimens.

• STI Policy Review
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• v.4 no.1
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• pp.74-93
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• 2013

Although open innovation (OI) has been an important research theme for over a decade, its theoretical framework has been relatively under-researched. As OI involves a wide range of innovation activities, a firm's capacities in the use of the various firm resources play a critical role in OI implementation. However, it is unclear how they affect firms' performances for little is known of OI capacities. Based on a theoretical framework derived from the literature, this study looks into the relationships between six OI capacities (inventive, absorptive, transformative, connective, innovative, and desorptive) and financial performance using the Korean Innovation Survey (KIS) 2008 data. The research model was tested using structural equation modelling (SEM) while potential differences in capacities between different firm groups were also investigated. The results indicate that 1) OI capacities are significantly associated with firms' financial performance; 2) capacities are highly correlated with one another; and 3) some capacities are differently configured between different types of firms. Findings suggest that policy makers should pay more attention to helping firms enhance OI capacities and attempt to develop relevant policies in order to complement inadequate capacities.

• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.6
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• pp.183-190
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• 2006

From the result of this research above, it may be summed up as follows. As a summary of results from each experiment, as the test body reinforced with the carbon rods was embedded inside the concrete section and made it possible uniform movement, this study has shown that it had excellent characteristics in improving the flexural strength and ductility. Also, it was considered as the carbon-steel sheet composite plate was to exert the strength more if it would complement the adherence with the concrete.

• Journal of the Korea institute for structural maintenance and inspection
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• v.19 no.5
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• pp.10-21
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• 2015

Many studies have been carried out on carbon fiber-reinforced plastic sheet(hereafter CFRP sheet)-confined concrete specimens for improve structural performance of concrete structures. To complement the existing studies, a parametric study is conducted to examine the effect of various design parameters such as layers of CFRP sheet, size and aspect ratio of specimens, and overlap length. The behavior of CFRP-confined concrete is compared using stress-strain curves of each specimen. And the strengthening effect of CFRP sheet is examined by maximum compressive strength. As the layers of CFRP sheet increases, structural performance of CFRP-confined concrete is significant increased. If the overlap length is more than 5% of circumstance, strengthening effect is not affected. In addition, a test database assembled from test results and existing studies is presented. Using these test database, accuracy and reliability of the existing strength models for CFRP-confined concrete are verified.

• Journal of the Korean Institute of Intelligent Systems
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• v.19 no.5
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• pp.720-724
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• 2009

This thesis analyze structure of consciousness of success factors of company project by applying FSM(Fuzzy Structural Modeling). FSM is a theory that implied fuzzy theory to ISM(Interpretive Structural Modeling) and is known to be more valid in recognizing a complex pluralistic value system and it is also designed to choose structure model that fits reality with when it is changed by parameter p and $\lambda$. It is desirable to conduct conformity assessment to complement even though selected structure model is considered as conformed because structure model is chosen without objective evaluation for conformity. Therefore, this paper present more objective structure model through conformity evaluation using structural equation modeling on success factors to achieve company project obtained by FSM and analyze the consciousness structure according to that structure.

• Journal of Distribution Science
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• v.22 no.4
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• pp.1-10
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• 2024

Purpose: This study is aimed to introduce the application of phantom approach with structural equation modelling method for online learning. By integrating these innovative methodologies, the research seeks to advance the understanding of how the phantom approach can effectively complement and augment structural equation modeling techniques. Research design, data and methodology: A theoretical framework of Technology Acceptance Model (TAM) was modified and updated. A questionnaire was developed and used to extract information from 189 instructors who used online learning as their primary medium. The Covariance Based Structural Equation Modelling (CBSEM) was applied to test the direct effects and the phantom approach is used to handle the 2 mediators in the model. Results:social influence, perceived usefulness, and perceived ease of use exerted discernible impacts on instructors' intentionsto engage in online learning. These findings illuminate the intricate dynamics influencing instructor behavior within the realm of online education, underscoring the significance of various factors in shaping their intentions. Conclusions: In additions, the perceived usefulness and perceived ease of use had mediated the effect of social influence and instructor intention using phantom approach. Therefore, one can have concluded that this modified model was also confirmed, thereby reinforcing distribution strategies to online learning and overall education presence.