• Journal of Distribution Science
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• v.11 no.5
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• pp.43-53
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• 2013

Purpose - The purpose of this study is to analyze the effectiveness of customer relationship management (CRM) support policies for facilitating traditional markets, especially with respect to customer acquisition and maintenance, and to investigate the factors affecting CRM. Research design, data, and methodology - We analyzed the CRM efficiency of traditional markets in 16 cities and provinces in Korea on the basis of DEA analysis and Malmquist productivity analysis. The DEA model calculates a ratio of the weighted mean of various inputs to the weighted mean of various outputs and measures the efficiency of a specific decision making unit (DMU), which is compared to the reference group that has a similar input-output structure. The input variables are coupon, event, parcel service, premiums, while is the number of customers per day. Further, through regression analysis, we analyzed CRM-related factors affecting traditional markets' customer appeal and revenue growth. Results - We obtained the results of the efficiency of traditional markets in 16 provinces. The traditional markets in Seoul, Busan, and Jeju were found to be efficient in a model CCR that used the number of customers per day as an output variable, while Chungbuk, Jeonbuk Province, and According to the results of the DEA analysis and Malmquist productivity analysis, large cities such as Seoul, Busan, and Jeju showed efficiency in CRM-related investment businesses in traditional markets for attracting customers. The Malmquist analysis results confirmed that the productivity of traditional markets increased from 2008 to 2010. The results of the regression analysis revealed that the "customer acquisition/maintenance factor" and the "offering of customer convenience facility factor" were significant to the daily average number of customers, which is a dependent variable. The results of the test with the mediating variable, "number of customers," and the final dependent variable, "sales revenue," were rejected. However, the variable "customer acquisition /maintenance" was found to affect sales revenue positively. Conclusions - It is necessary to enhance the business not only for promotional activities to attract customers, but also to strengthen customer relationships among CRM businesses, such as through the management of key customers. The regression analysis results showed that CRM businesses have yet to produce an increase in sales revenues in traditional markets. Therefore, to help customers who visit traditional markets to keep buying products, it is necessary to prepare various investment methods and provide support to improve "customer loyalty." This study has a limitation in terms of CRM-related statistics. Therefore, in the future, it is necessary to conduct a survey of customers who use traditional markets to analyze the markets by type and size as well as the CRM-related factors. Based on the analysis, we will try to perform a variety of statistical analyses, including structural equations.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.4
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• pp.505-516
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• 2018

The purpose of the present study was to examine the mediating effect of self-concealment on the relationship between self-critical perfectionism and disordered eating behavior. Toward this aim, 348 participants responded to the measures of self-critical perfectionism, self-concealment and disordered eating behavior. Correlation analysis revealed that self-critical perfectionism was positively correlated with self-concealment and disordered eating behavior. In addition, self-concealment was positively correlated with disordered eating behavior. Structural equations analysis found that the relationship between self-critical perfectionism and disordered eating behavior had a significant partial mediating effect on self-concealment, meaning that self-critical perfectionism increased disordered eating behavior through high levels of self-concealment. This finding suggests that individuals who place high standards on themselves, and feature fear of negative evaluation from others, are at greater risk for disordered eating behavior. Based on this finding, we discussed suggestions for future research and clinical implications.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.3 s.357
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• pp.7-17
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• 2007

An analysis and design theory of an aperture-coupled cavity-fed back-to-back microstrip directional coupler is presented for the efficient and optimized design. For this purpose, an equivalent network is developed, and simple but accurate calculations of circuit element values are described. Design equations of the coupler are derived based on the equivalent circuit. In order to determine various structural design parameters, the evolutionary hybrid optimization method based on the genetic algorithm and Nelder-Mead method is invoked. As a validation check of the proposed theory and optimized design method, a 10 dB directional coupler was designed and fabricated. The measured coupling was 10.3 dB at 3 GHz, and the return loss and isolation were 31.8 dB and 30.5 dB, respectively. The directional coupler also showed very good quadrature phase characteristics. Good agreements between the measured and the design specifications fully validate the proposed network analysis and design procedure.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.4
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• pp.737-752
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• 1992

Analysis of elasto-dynamic deformation of flexible linkage mechanism is conducted using the finite element method. The equations of motion of the system are derived from the static structural problem in which dynamic inertia, gravitational and driving forces are treated as external loads. Linear spring model is included in the formulation of equation of motions to represent the effects of deformation of elastic bearings of revolute joints on the system behavior. A computer program is constructed and applied to analyze a specific crank-lever 4-bar mechanism. The algorithm of the program is as follows. First, the natural frequencies and the mode shapes of the system are calculated by solving the eigenproblem of the mechanism system which can be considered as a static structure by assuming the input shaft (crank shaft) to be fixed at any given configuration of mechanism. And finally, the elasto-dynamic deformation of the whole system is obtained using mode superposition method for the case of constant input speed. The effect of geometric stiffness on the mechamism is included in the program with the axial forces of links obtained through the quasi-static displacement analysis. It is found that the geometric stiffness exerts an important effect upon the elasto-dynamic behavior of the flexible linkage mechanism. Elastic deformation of bearing lowers the natural frequencies of the system, resulting smaller elastic displacement at the mid-point of the links and bigger elestic displacement at the ends of the links than rigid bearing. The above investigation of flexible linkage mechanism shows that the effects of the elastic deformation of bearing on the mechanism should be considered to design the mechanism which satisfies more preciously the purpose and the condition of design.

• Applied Chemistry for Engineering
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• v.24 no.4
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• pp.370-374
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• 2013

The effects of zinc chloride addition on pore development of porous carbon nanofibers prepared by polyacrylonitrile (PAN)/ N,N'-dimethylformamide (DMF) (10 wt%) electrospinning were investigated. The change of morphological and structural modification by zinc chloride activation was investigated by a scanning electron microscopy (SEM) analysis. $N_2$ adsorption isotherm characteristics at 77 K were confirmed by Brunauer-Emmett-Teller (BET) and Horvath-Kawazoe (H-K) equations, and the curves showed the Type I mode in the International Union of Pore and Applied Chemistry (IUPAC) classification, indicating that lots of micropores exist in the sample. In addition, specific surface areas and total pore volumes of porous carbons prepared by the zinc chloride activation were determined as 600~980 $m^2/g$ and 0.24~0.40 $cm^3/g$, respectively. As experimental results, many holes or demolished structures were found on the fiber surfaces after the zinc chloride activation as confirmed by a SEM analysis. It was also observed that various pore sizes were found to be depended on the adding content of zinc chloride in PAN/DMF solution in this system.

• Interaction and multiscale mechanics
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• v.2 no.1
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• pp.69-89
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• 2009

Reinforced and prestressed concrete (RC and PC) thin walls are crucial to the safety and serviceability of structures subjected to shear. The shear strengths of elements in walls depend strongly on the softening of concrete struts in the principal compression direction due to the principal tension in the perpendicular direction. The past three decades have seen a rapid development of knowledge in shear of reinforced concrete structures. Various rational models have been proposed that are based on the smeared-crack concept and can satisfy Navier's three principles of mechanics of materials (i.e., stress equilibrium, strain compatibility and constitutive laws). The Cyclic Softened Membrane Model (CSMM) is one such rational model developed at the University of Houston, which is being efficiently used to predict the behavior of RC/PC structures critical in shear. CSMM for RC has already been implemented into finite element framework of OpenSees (Fenves 2005) to come up with a finite element program called Simulation of Reinforced Concrete Structures (SRCS) (Zhong 2005, Mo et al. 2008). CSMM for PC is being currently implemented into SRCS to make the program applicable to reinforced as well as prestressed concrete. The generalized program is called Simulation of Concrete Structures (SCS). In this paper, the CSMM for RC/PC in material scale is first introduced. Basically, the constitutive relationships of the materials, including uniaxial constitutive relationship of concrete, uniaxial constitutive relationships of reinforcements embedded in concrete and constitutive relationship of concrete in shear, are determined by testing RC/PC full-scale panels in a Universal Panel Tester available at the University of Houston. The formulation in element scale is then derived, including equilibrium and compatibility equations, relationship between biaxial strains and uniaxial strains, material stiffness matrix and RC plane stress element. Finally the formulated results with RC/PC plane stress elements are implemented in structure scale into a finite element program based on the framework of OpenSees to predict the structural behavior of RC/PC thin-walled structures subjected to earthquake-type loading. The accuracy of the multiscale modeling technique is validated by comparing the simulated responses of RC shear walls subjected to reversed cyclic loading and shake table excitations with test data. The response of a post tensioned precast column under reversed cyclic loads has also been simulated to check the accuracy of SCS which is currently under development. This multiscale modeling technique greatly improves the simulation capability of RC thin-walled structures available to researchers and engineers.

• Steel and Composite Structures
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• v.36 no.5
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• pp.553-568
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• 2020

Steel-concrete composite structures have been extensively used in building, bridges, and other civil engineering infrastructure. Shear stud connectors between steel and concrete are essential in composite members to guarantee the effectiveness of their behavior in terms of strength and deformability. This study focuses on investigating the shear stiffness of headed studs embedded in several types of concrete with wide range of compressive strength, and their effects on the elastic behavior of steel-concrete composite girders were evaluated. Firstly, totally 206 monotonic push-out tests from the literature were reviewed to investigate the shear stiffness of headed studs embedded in various types of concrete (NC, HPC, UHPC etc.). Shear stiffness of studs is defined as the secant stiffness of the load-slip curve at 0.5V_u, and a formulation for predicting defined shear stiffness in elastic state was proposed, indicating that the stud diameter and the elastic modulus of steel and concrete are the main factors. And the shear stiffness predicted by the new formula agree well with test results for studs with a diameter ranging from 10 to 30 mm in the concrete with compressive strength ranging from 22.0 to 200.0MPa. Then, the effects of shear stiffness on the elastic behaviors of composite girders with different sizes and under different loading conditions were analyzed, the equations for calculating the stress and deformation of simply supported composite girders considering the influence of connection's shear stiffness were derived under different loading conditions using classical linear partial-interaction theory. As the increasing of shear stiffness, the stress and deflection at the most unfavorable section under partial connected condition tend to be those under full connected condition, but the approaching speed decreases gradually. Finally, the connector's shear stiffness was recommended for fully connection in composite girders with different dimensions under different loading conditions. The findings from present study may provide a reference for the prediction of shear stiffness for headed studs and the elastic design of steel-concrete composite girder.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.38 no.2
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• pp.193-202
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• 2018

This paper proposed a crack spacing calculation formulation which is an important parameter for calculating the crack width, that is the main factor for verification of serviceability limit states and durability performance evaluation of reinforced concrete members. The basic equation of average crack spacing is derived by considering the bond characteristics which is the governing equation for the analysis of cracking behavior in reinforced concrete members. In order to consider the effect of the cover thickness and concrete compressive strength, the crack spacing measured in 124 direct tensile tests performed by several researchers was analyzed and each coefficient was proposed. And, correlation analysis was performed from 80 specimen data where the maximum and average crack spacing were simultaneously measured, and a correlation coefficient that can easily predict the maximum crack spacing from the average crack spacing was proposed. The results of the proposed average crack spacing equation and maximum crack spacing correlation were compared with those current design code specification. The comparisons of proposed equations and the Korean design codes show that the proposed formulation for the average crack spacing and the maximum crack spacing improves the accuracy and reliability of prediction compared to the corresponding provisions of the Korean Concrete Structural Design Code and Korean Highway Bridge Design Code (Limit States Design).

• Journal of the Korean Society for Marine Environment & Energy
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• v.14 no.2
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• pp.114-120
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• 2011

The characteristics of a helical turbine to be used for tidal stream energy conversion have been numerically studied with varying a few design parameters. The helical turbines were proposed aiming at mitgating the well known poor cut-in characteristics and the structural vibration caused by the fluctuating torque, and the basic concept is introducing some twisting angle of the vertical blade along the rotation axis of the turbine. Among many potential controling parameters, we focused, in this paper, on the twisting angle and the height to diameter ratio of the turbine, and, based on the numerical experiment, We tried to propose a configuration of such turbine for which better performance can be expected. The three-dimensional unsteady RANS equations were solved by using the commercial CFD software, FLUENT with k-${\omega}$ SST turbulence model, and the grid was generated by GAMBIT. It is shown that there are a range of the twisting angle producing better efficiency with less vibration and the minimum height to diameter ratio above which the efficiency does not improve considerably.

• Journal of Technology Innovation
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• v.23 no.1
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• pp.61-86
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• 2015

This study provides an empirical analysis based on 2012 Korea Innovation Survey (STEPI) to investigate the relation between R&D cooperation and in-house R&D investment. The study further analyzes the effect of the R&D cooperation and in-house R&D investment on technical innovation. First, the relation between company's in-house R&D investment and R&D cooperations is estimated with the two equations using SUR models. Second, the effect of in-house R&D investment and R&D cooperation on the company's technical innovation is estimated using Probit model. This study differs from other existing R&D studies using Korean data in that empirical models are based on structural relationships among in-house R&D, R&D cooperation, and technical innovation. The results can be summarized as follows; the R&D cooperation expands the in-house R&D investment and the in-house R&D strengthen the R&D cooperation. Furthermore, In-house R&D investment increases the chances of success in innovation. As we obtain evidence of complementary relation between R&D cooperation and in-house R&D investment, it is necessary to develop environment conducive to this complementarity in order to have more efficient R&D system.