• 한국기계가공학회지
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• 제16권6호
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• pp.69-74
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• 2017

In the current machining industry, machining precision is necessary and machining is being carried out. In this ultra-precision machining industry, the fixation of the workpiece is very important and the degree of machining depends on the degree of fixation of the workpiece. In ultra-precision machining, various methods, such as using a vise chuck or the like and using bolt nut coupling, are used for fixing a workpiece to an existing machine tool. In particular, when the precision gripping force of the jig is insufficient during machining of the ultra-precision mold parts, the machining material shakes due to the vibration or friction, and the machining precision is lowered. In the ultra-precision machining of power transmission parts, such as gears, the accuracy of the product is then determined. In addition, the amount of heat generated during machining has a significant effect on the machining accuracy. This is because the vibration value changes according to the grasp force of the jig that fixes the workpiece, and the change in the calorific value due to the change in the main shaft rotation speed of the ultra-precision machining. The increase in the spindle rotation speed during machining decreased the heat generation during machining, and the machining accuracy was also good, and it was confirmed that the machining heat changed according to the fixed state of the workpiece and the machining accuracy also changed. In this study, we try to optimize the driving part of the power vise by using structural analysis, rather than the power vise, using the basic mechanical-type power unit.

• 복식문화연구
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• 제12권1호
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• pp.59-72
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• 2004

The objectives of this study were to investigate the perceptions of Korean female university students for clothing pattern tendency and structural element of clothing pattern image dimension and to find how individual personality type influence the preferred clothing pattern characteristics. For this study, a questionnaire was designed and sent to 600 female university students of Daejeon, Seoul and metropolitan area. The tool used in this study was MBTI(The Myers-Briggs Type Indicator) Form G Korean version and for the analysis of data SPSS 10.0 package were used. 10 representative patterns for this study were floral, dot, stripe, check, animal, abstract & artistic, geometric, vegetable & leaf, paisely, patchwork pattern. The data were analyzed by factor analysis, arithmetic mean, One-Way ANOVA, x²-test. The major findings were as follows: Clothing pattern image dimension perceived by Korean female university students for 10 representative patterns were basic form, deluxe, specialty, and cultural dimension. Among them, basic form and deluxe dimension were major dimensions. In basic form dimension, dot pattern score was high indicating female students perceive it as light, comfortable, clean, cool and simple pattern image. In deluxe dimension, floral pattern scored high and in specialty dimension, abstract and artistic pattern scored high among other pattern image. In cultural dimension, geometric pattern and check pattern scored high. Based on other detailed analysis results, It is concluded that the personality type greatly influence clothing pattern evaluation. For example, in case of color combination of patchwork pattern, there was a difference in color preference depend on a personality type such as sensing(S) or intuition(N). Therefore, sensing personality type preferred adjacent color combination than contrast color combination. Detailed marketing strategy is necessary in planning textile design of merchandise plan.

• 농촌계획
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• 제23권4호
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• pp.99-110
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• 2017

This study is to analyze the spatial structure and POE of Jungja(pavilion) shelter for rural village regeneration. 14 Jungja shelter space at rural villages in Gyungbuk province, were investigated. An interview questionnaire was conducted for total 139 residents as POE. The use behavior and satisfaction for Jungja shelter space, were investigated. The statistical analysis were mean of satisfactions, reliability, factor analysis, and multiple regression analysis. The results and discussions can be objective data for rural village regeneration. In satisfaction level, 'Continuous use intention'(3.99), 'Well-suited approach'(3.87), and 'Helpful in resident living'(3.84) were shown to be high points of agreement in 5 point Likert type scale. But, the mean points were low as 2.01 in 'Surrounding landscape', 'Creation of green areas'(3.22), and 'Traffic safety'(3.22), respectively. Within use satisfaction, 5 factors were categorized, 'Use', 'Safety', 'Facility', 'Management' and 'Users'. By the result of multiple regression analysis, variables of 'Continuous use', 'Convenient location', and 'Image improvement', were shown to be main affecting variables to overall satisfaction. Furthermore, in spatial structure analysis, 4 types were categorized with the aspect of landform, roads, and location in village. The levels of satisfaction were shown to be high in village type of semi-open, road type of circular, and location type of center/back. Conclusively, these findings could be utilized as basic data and useful tool of space-structural satisfaction analytic method, and for each stage of planning/design and remodeling for rural village regeneration.

• Molecules and Cells
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• 제28권5호
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• pp.447-453
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• 2009

The quorum sensing (QS) inhibitors that antagonize TraR, a receptor protein for N-3-oxo-octanoyl-L-homoserine lactones (3-oxo-C8-HSL), a QS signal of Agrobacterium tumefaciens were developed. The structural analogues of 3-oxo-C8-HSL were designed by in silico molecular modeling using SYBYL packages, and synthesized by the solid phase organic synthesis (SPOS) method, where the carboxamide bond of 3-oxo-C8-HSL was replaced with a nicotinamide or a sulfonamide bond to make derivatives of N-nicotinyl-L-homoserine lactones or N-sulfonyl-L-homoserine lactones. The in vivo inhibitory activities of these compounds against QS signaling were assayed using reporter systems and compared with the estimated binding energies from the modeling study. This comparison showed fairly good correlation, suggesting that the in silico interpretation of ligand-receptor structures can be a valuable tool for the pre-design of better competitive inhibitors. In addition, these inhibitors also showed anti-biofilm activities against Pseudomonas aeruginosa.

• Structural Engineering and Mechanics
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• 제73권5호
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• pp.529-542
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• 2020

As limited well-documented experimental data are available for assessing the attributes of different deformation components of flanged walls, few appropriate models have been established for predicting the inelastic responses of flanged walls, especially those of asymmetrical flanged walls. This study presents the experimental results for three large-scale T-shaped reinforced concrete walls and examines the variations in the flexural, shear, and sliding components of deformation with the total deformation over the entire loading process. Based on the observed deformation behavior, a simple model based on moment-curvature analysis is established to estimate flexural deformations, in which the changes in plastic hinge length are considered and the deformations due to strain penetration are modeled individually. Based on the similar gross shapes of the curvature and shear strain distributions over the wall height, a proportional relationship is established between shear displacement and flexural rotation. By integrating the deformations due to flexure, shear, and strain penetration, a new load-deformation analytical model is proposed for flexure-dominant flanged walls. The proposed model provides engineers with a simple, accurate modeling tool appropriate for routine design work that can be applied to flexural walls with arbitrary sections and is capable of determining displacements at any position over the wall height. By further simplifying the analytical model, a simple procedure for estimating the ultimate displacement capacity of flanged walls is proposed, which will be valuable for performance-based seismic designs and seismic capacity evaluations.

• Earthquakes and Structures
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• 제17권5호
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• pp.511-519
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• 2019

The concrete gravity dam is one of the most important parts of the nation's infrastructure. Besides the benefits, the dam also has some potentially catastrophic disasters related to the life of citizens directly. During the lifetime of service, some degradations in a dam may occur as consequences of operating conditions, environmental aspects and deterioration in materials from natural causes, especially from dynamic loads. Cumulative Absolute Velocity (CAV) plays a key role to assess the operational condition of a structure under seismic hazard. In previous researches, CAV is normally used in Nuclear Power Plant (NPP) fields, but there are no particular criteria or studies that have been made on dam structure. This paper presents a method to calculate the limitation of CAV for the Bohyeonsan Dam in Korea, where the critical Peak Ground Acceleration (PGA) is estimated from twelve sets of selected earthquakes based on High Confidence of Low Probability of Failure (HCLPF). HCLPF point denotes 5% damage probability with 95% confidence level in the fragility curve, and the corresponding PGA expresses the crucial acceleration of this dam. For determining the status of the dam, a 2D finite element model is simulated by ABAQUS. At first, the dam's parameters are optimized by the Minitab tool using the method of Central Composite Design (CCD) for increasing model reliability. Then the Response Surface Methodology (RSM) is used for updating the model and the optimization is implemented from the selected model parameters. Finally, the recorded response of the concrete gravity dam is compared against the results obtained from solving the numerical model for identifying the physical condition of the structure.

• Smart Structures and Systems
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• 제13권2호
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• pp.257-280
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• 2014

In this paper, a novel PARAllel FACtor (PARAFAC) decomposition based Blind Source Separation (BSS) algorithm is proposed for modal identification of structures equipped with tuned mass dampers. Tuned mass dampers (TMDs) are extremely effective vibration absorbers in tall flexible structures, but prone to get de-tuned due to accidental changes in structural properties, alteration in operating conditions, and incorrect design forecasts. Presence of closely spaced modes in structures coupled with TMDs renders output-only modal identification difficult. Over the last decade, second-order BSS algorithms have shown significant promise in the area of ambient modal identification. These methods employ joint diagonalization of covariance matrices of measurements to estimate the mixing matrix (mode shape coefficients) and sources (modal responses). Recently, PARAFAC BSS model has evolved as a powerful multi-linear algebra tool for decomposing an $n^{th}$ order tensor into a number of rank-1 tensors. This method is utilized in the context of modal identification in the present study. Covariance matrices of measurements at several lags are used to form a $3^{rd}$ order tensor and then PARAFAC decomposition is employed to obtain the desired number of components, comprising of modal responses and the mixing matrix. The strong uniqueness properties of PARAFAC models enable direct source separation with fine spectral resolution even in cases where the number of sensor observations is less compared to the number of target modes, i.e., the underdetermined case. This capability is exploited to separate closely spaced modes of the TMDs using partial measurements, and subsequently to estimate modal parameters. The proposed method is validated using extensive numerical studies comprising of multi-degree-of-freedom simulation models equipped with TMDs, as well as with an experimental set-up.

• Steel and Composite Structures
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• 제31권1호
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• pp.69-83
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• 2019

This paper investigates the structural behavior of very high strength concrete encased steel composite columns via combined experimental and analytical study. The experimental programme examines stub composite columns under pure compression and eccentric compression. The experimental results show that the high strength encased concrete composite column exhibits brittle post peak behavior and low ductility but has acceptable compressive resistance. The high strength concrete encased composite column subjected to early spalling and initial flexural cracking due to its brittle nature that may degrade the stiffness and ultimate resistance. The analytical study compares the current code methods (ACI 318, Eurocode 4, AISC 360 and Chinese JGJ 138) in predicting the compressive resistance of the high strength concrete encased composite columns to verify the accuracy. The plastic design resistance may not be fully achieved. A database including the concrete encased composite column under concentered and eccentric compression is established to verify the predictions using the proposed elastic, elastoplastic and plastic methods. Image-oriented intelligent recognition tool-based fiber element method is programmed to predict the load resistances. It is found that the plastic method can give an accurate prediction of the load resistance for the encased composite column using normal strength concrete (20-60 MPa) while the elastoplastic method provides reasonably conservative predictions for the encased composite column using high strength concrete (60-120 MPa).

• 한국프랜차이즈경영연구
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• 제10권4호
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• pp.43-52
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• 2019

Purpose: As a research on the effects of the characteristics of franchise educational institution and contents on the educational transition, commitment, and recommendation intention, this study aimed to suggest the basic data that could be used for the performance of educational training of franchise headquarters, and also to suggest an empirical research helpful for the development of actual educational system and the operation of curriculum for franchise educational institutions. Research design, data, and methodology: This study selected the trainees who recently completed the training in a franchise educational institution as the samples. The survey was conducted for 20 days from October 1st to October 20th 2018, targeting total 230 people, and total 207 questionnaires were collected (Missing value 23). To verify the validity of the measurement tool used for this study, this study reviewed the factor loading of each factor by conducting the confirmatory factor analysis(CFA), and then verified the average variance extracted(AVE) and the composite construct reliability(CCR). Lastly, the structural equation model(SEM) was verified based on the research hypotheses and research model. The SPSS Win Ver. 20.0 & AMOS 20.0 were used for every analysis of this study. Results: The results of this study could be summarized as follows. First, the reputation and interaction of the characteristics of franchise educational institution had significantly positive(+) effects on the educational transition. Second, all the sub - variables of educational contents such as job relevance, education method, and instructors' professionalism had positive(+) effects on the educational transition while the educational transition had positive effects on the organizational commitment, career commitment, and job commitment. Lastly, the organizational commitment and job commitment had positive(+) effects on the recommendation intention. Thus, the trainees with higher organizational commitment and job commitment in a franchise educational institution, showed higher intention to recommend the educational institution to others. Conclusions: The results of this study imply that the franchise educational institutions could increase the actual performance of education such as educational transition, commitment, and recommendation intention by increasing interactions within educational institutions and also designing effective educational contents, so that the trainees could highly perceive the educational transition of education.

• 시스템엔지니어링학술지
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• 제16권2호
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• pp.27-37
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• 2020

The Fukushima Daiichi accident in 2011 revealed some vulnerabilities of existing Nuclear Power Plants (NPPs) under extended Station Blackout (SBO) accident conditions. One of the key Severe Accident Management (SAM) strategies developed post Fukushima accident is the In-Vessel Retention (IVR) Strategy which aims to retain the structural integrity of the Reactor Pressure Vessel (RPV). RELAP/SCDAPSIM/MOD3.4 is selected to predict the thermal-hydraulic response of APR1400 undergoing an extended SBO. To assess the effectiveness of the IVR strategy, it is essential to quantify the underlying uncertainties. In this work, both the epistemic and aleatory uncertainties are considered to identify the success window of the IVR strategy. A set of in-vessel relevant phenomena were identified based on Phenomena Identification and Ranking Tables (PIRT) developed for severe accidents and propagated through the thermal-hydraulic model using Wilk's sampling method. For this work, a Systems Engineering (SE) approach is applied to facilitate the development process of assessing the reliability and robustness of the APR1400 IVR strategy. Specifically, the Kossiakoff SE method is used to identify the requirements, functions and physical architecture, and to develop a design verification and validation plan. Using the SE approach provides a systematic tool to successfully achieve the research goal by linking each requirement to a verification or validation test with predefined success criteria at each stage of the model development. The developed model identified the conditions necessary for successful implementation of the IVR strategy which maintains the vessel integrity and prevents a melt-through.