• Journal of Wind Energy
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• v.14 no.1
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• pp.29-36
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• 2023

The analysis of the floating offshore wind turbine platform is based on the procedures provided by the IEC including the International Classification Society, which recommends the analysis in the time domain. But time-domain simulation requires a lot of time and resources to solve tens of thousands of DLCs. This acts as a barrier in terms of floating structure development. For final verification, it requires very precise analysis in the time domain, but from an initial design point of view, a simplified verification procedure to predict the quantity of materials quickly and achieve relatively accurate results is crucial. In this study, a structural design procedure using a design wave applied in the oil and gas industries is presented combined with a conservative turbine load. With this method, a quick design spiral can be rotated, and it is possible to review FOWTs of various shapes and sizes. Consequently, a KRISO Semi-Submersible FOWT platform was developed using a simplified design procedure in frequency-domain analysis.

• Journal of Information Technology Services
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• v.13 no.1
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• pp.161-179
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• 2014

Added value of music industry in Korea is not distributed and calculated properly, and this obstacle brings various problems in a creative environment. Meanwhile, a new business model such as Open Collaboration, Crowdsourcing and platform that makes decisions and innovation from external resources has been appeared in commercial area. This new model like a composer delivers to consumers directly through Youtube.com, and multi collaboration is applied to the music industry, and it enables a new type of mechanism for creation, distribution, division, and calculation of music. However there are not enough empirical study of the music market because existing relative researches has been centered around fundamental concepts and application methodologies. This research defines Open Collaboration Platform in the music industry, and studies affecting factors of Participation Intention for example Justice, Information System Quality and Perceived Value. For a survey we apply PLS(Partial Least Square) to analyse Equity, Information System Quality and structural equation between Perceived Value and Participation Intention. Analysis results show Distributive Justice and Procedural Justice affects Platform Trust, and Service Quality, Economical Value and Emotional Value affects Platform Usefulness. Also Platform Trust and Platform Usefulness affects Platform Participation Intention. We discussed academic and practical implication based on research results.

• Ocean Systems Engineering
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• v.8 no.3
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• pp.329-343
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• 2018

The inclination of seabed profile (sloped seabed) is one of the known topographic features which can be observed at different seabed level in the large offshore basin. A mooring system connected between the platform and global seabed is an integral part of the floating structure which tries to keep the floating platform settled in its own position against hostile sea environment. This paper deals with an investigation of the motion responses of an FPSO platform moored on the sloped seabed under the combined action of wave, wind and current loads. A three-dimensional panel discretization method has been used to model the floating body. To introduce the connection of multi-segmented non-linear elastic catenary mooring cables with the sloped seabed, a quasi-static composite catenary model is employed. The model and analysis have been completed by using hydrodynamic diffraction code AQWA. Validation of the numerical model has been successfully carried out with an experimental work published in the latest literature. The analysis procedure in this study has been followed time domain analysis. The study involves an objective oriented investigation on platform motions, in order to identify the effects of the slopped seabed, the action of the wave, wind and current loads and the presence of riser system. In the end, an effective analysis has been performed to identify a stable mooring model in demand of reducing structural responses of the FPSO.

• Smart Structures and Systems
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• v.11 no.6
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• pp.589-604
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• 2013

Identification of damage has become an evolving area of research over the last few decades with increasing the need of online health monitoring of the large structures. The visual damage detection can be impractical, expensive and ineffective in case of large structures, e.g., offshore platforms, offshore pipelines, multi-storied buildings and bridges. Damage in a system causes a change in the dynamic properties of the system. The structural damage is typically a local phenomenon, which tends to be captured by higher frequency signals. Most of vibration-based damage detection methods require modal properties that are obtained from measured signals through the system identification techniques. However, the modal properties such as natural frequencies and mode shapes are not such good sensitive indication of structural damage. Identification of damaged jacket type offshore platform members, based on wavelet packet transform is presented in this paper. The jacket platform is excited by simple wave load. Response of actual jacket needs to be measured. Dynamic signals are measured by finite element analysis result. It is assumed that this is actual response of the platform measured in the field. The dynamic signals first decomposed into wavelet packet components. Then eliminating some of the component signals (eliminate approximation component of wavelet packet decomposition), component energies of remained signal (detail components) are calculated and used for damage assessment. This method is called Detail Signal Energy Rate Index (DSERI). The results show that reduced wavelet packet component energies are good candidate indices which are sensitive to structural damage. These component energies can be used for damage assessment including identifying damage occurrence and are applicable for finding damages' location.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.30 no.3
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• pp.109-116
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• 2022

A modular platform development technique was proposed to minimize development cost and development period by utilizing the already developed unmanned Aerial target AVT, which has been operated and verified for many years. New Mission Profile was designed and structural analysis was performed through finite element analysis (FEA) by analyzing mission requirements for visual short-range, non-visible mid-range, and long-range targets. The targets are used for guided missile anti-aircraft training. In addition, avionics systems including flight control computers for autonomous flights were developed to verify their conformance by performing launcher take-off tests with rapid acceleration changes and autonomous flight tests at a maximum speed of 300km per hour.

• Journal of Fashion Business
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• v.27 no.4
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• pp.38-49
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• 2023

Fashion vertical platforms offer various content and events to consumers and have established a strong customer base. Especially, they cater to the sensibilities of young customers. This study analyzed the characteristics of a sensuous fashion vertical platform, which enhances expertise and provides customized services. In addition, this study aimed to find out whether consumer innovation modulates the relationship between fashion vertical platform, platform satisfaction, and continuous shopping intention. An online survey was conducted targeting consumers in their 20s and 30s who had experience using fashion vertical platforms, and 222 samples were analyzed. Factor analysis and structural equation model were analyzed using the SPSS 29.0 and Smart-PLS. Smart-PLS analysis results showed that exclusivity, convenience and informativeness did not directly affect continuous shopping intention but showed a complete mediating effect through platform satisfaction. Both the high and low innovative groups demonstrated significant effects of exclusivity on platform satisfaction, and platform satisfaction showed significant effects on continuous shopping intention. A high level of innovation among the consumers showed significant mediating effects on exclusivity, personalization, and continuous shopping intention, as reflected by information on platform satisfaction, and low level of innovation among the consumers showed significant effect on convenience. This study's findings highlight the importance of enhancing exclusivity, convenience, informativeness, and esthetics in fashion vertical platforms, and improving platform satisfaction. These findings will be used to develop marketing strategies that can lead to continuous shopping intentions and provide opportunities for the industry.

• Structural Engineering and Mechanics
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• v.71 no.5
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• pp.553-562
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• 2019

This paper presents the results of a study into the dynamic behaviour of a support structure of a mobile elevating work platform. The vibrations of the mechanical system of the observed structure are examined analytically, numerically, and experimentally. Within the analytical examination, a simple mathematical model is developed to describe free and forced vibrations. The dynamic analysis of the mechanical system is conducted using a discrete dynamic model with a reduced number of vibrational degrees of freedom. On the basis of the expression for the system energy, and by applying Lagrange's equations of the second kind, differential equations are derived for system vibrations, frequencies are determined, and the laws of forced platform vibration are established. At the same time, a nonlinear FEM model is developed and the laws of free and forced vibration are determined. The experimental and numerical part of the study deal with the examination of the real structure in extreme conditions, taking into account: the lowest eigenfrequency, forced actions that could endanger the general stability, the maximal amplitudes, and the acceleration of the work platform. The obtained analytical and numerical results are compared with the experiments. The experimental verification points to the adverse behaviour of the platform in excitation cases - swaying. In such a situation, even a relatively small physical force can lead to unacceptably high amplitudes of displacement and acceleration - exceeding the usual work values.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2005.03a
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• pp.269-276
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• 2005

A web-based platform for nonlinear earthquake analysis on SDOF systems has been developed in the research. The proposed web-based platform is a 2-tier system composed of client and server sides. Smart Client is applied for the client side to improve the handling speed and UI compatible to the stand alone systems. For the server side, MSSQL is used as a storage for the web. XML WebService is adpoted for the networking between client and server. To examine the efficiency of the developed web-based platform, a trial study on a SDOF nonlinear structural system under earthquake excitation has been carried out.

• Composites Research
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• v.36 no.2
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• pp.108-116
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• 2023

In this paper, kinematic design and multi-body dynamics analysis were conducted to develop a small manipulator platform for automating the maintenance of structures made of composite materials. To design manipulator kinematically, the existing composite repair process was considered. The 3D design was conducted after selecting the basic specifications of manipulator and end-effecter in consideration of the patch lamination process for repair. Then, variables necessary for simulation and control were generated in MATLAB through inverse kinematic analysis. To evaluate the structural stability of platform, multibody dynamics analysis was conducted using Altair Inspire and Optistruct. Based on the simulation conducted in Inspire, multibody dynamics analysis was conducted in Optistruct, and structural stability was verified through the results of maximum displacement and Von-Mises stress over time. To verify the design, manufacturing and controlling of platform were conducted and compared with the simulation. It was confirmed that the actual repair process path and the simulation showed a good agreement.

• Smart Structures and Systems
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• v.9 no.1
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• pp.71-104
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• 2012

In this research, a typical tension-leg type of floating platform incorporated with an innovative concept of underwater tuned liquid column damper system (UWTLCD) is studied. The purpose of this study is to improve the structural safety by means of mitigating the wave induced vibrations and stresses on the offshore floating Tension Leg Platform (TLP) system. Based on some encouraging results from a previous study, where a Tuned Liquid Column Damper (TLCD) system was employed in a floating platform system to reduce the vibration of the main structure, in this study, the traditional TLCD system was modified and tested. Firstly, the orifice-tube was replaced with a smaller horizontal tube and secondly, the TLCD system was combined into the pontoon system under the platform. The modification creates a multipurpose pontoon system associated with vibration mitigation function. On the other hand, the UWTLCD that is installed underwater instead would not occupy any additional space on the platform and yet provide buoyancy to the system. Experimental tests were performed for the mitigation effect and parameters besides the wave conditions, such as pontoon draught and liquid-length in the TLCD were taken into account in the test. It is found that the accurately tuned UWTLCD system could effectively reduce the dynamic response of the offshore platform system in terms of both the vibration amplitude and tensile forces measured in the mooring tethers.