• Steel and Composite Structures
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• v.16 no.4
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• pp.389-415
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• 2014

This study deals with dynamic model of composite sandwich panels with functionally graded flexible cores under low velocity impacts of multiple large or small masses using a new improved higher order sandwich panel theory (IHSAPT). In-plane stresses were considered for the functionally graded core and face sheets. The formulation was based on the first order shear deformation theory for the composite face sheets and polynomial description of the displacement fields in the core that was based on the second Frostig's model. Fully dynamic effects of the functionally graded core and face-sheets were considered in this study. Impacts were assumed to occur simultaneously and normally over the top and/or bottom of the face-sheets with arbitrary different masses and initial velocities. The contact forces between the panel and impactors were treated as internal forces of the system. Nonlinear contact stiffness was linearized with a newly presented improved analytical method in this paper. The results were validated by comparing the analytical, numerical and experimental results published in the latest literature.

• Korean Journal of Human Ecology
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• v.3 no.1
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• pp.40-50
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• 2000

The purpose of this study is to investigate the influential variables related to the value orientation and environmental preservation behavior. This study is also to provide data for environment education. The subjects were 538 children, in June. 1998, in Kwangju. The data obtained were analyzed by Pearson's correlation. Cronbach's u coefficient. multiple regression. and Path analysis. The major findings were as follows : 1) The influential variables for childrens'egoistic value orientation were grade level of children and education level of mother The influential variables for childrens'altruistic orientation were the frequency of contact for environmental information and age of mother. The influential variables for childrens'biospheric orientation were education level of mother and the frequency of contact for environmental information. 2) The influential variables for the childrens'behavior on the environmental preservation were the frequency of contact for environmental information. biospheric orientation. grade level of children and education level of mother.

• Journal of the Korean Society of Clothing and Textiles
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• v.28 no.8
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• pp.1186-1195
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• 2004

The purposes of this study were to investigate the factors of CRM activity and the difference in CRM activities of department stores and to analyze the effect of CRM activities on customer satisfaction and loyalty. Investigators interviewed the buyers of three department stores in Daejeon area and surveyed 468 people aged over 20 who did shopping those stores. The data were analyzed with factorial analysis, multiple regression analysis, path analysis, ANOVA, Scheffe Test, etc., using the SPSS 10.0. The results of this study were: 1) Six factors were identified: ＇benefit ＆ information＇, ＇service＇, ＇customer invitation＇, ＇customer contact＇, ＇special management＇, and ＇purchase-related help＇; 2) CRM activities of three department stores were different, and department store buyers and customers were different in perception on CRM activities; and 3) Customer satisfaction was affected by the CRM factors like ＇service＇, ＇customer invitation＇, ＇purchase-related help＇, ＇benefit ＆ information＇, and ＇customer contact＇ Customer loyalty were affected directly by customer satisfaction, ＇benefit ＆ information＇ and ＇service＇, and indirectly by ＇customer invitation＇, ＇purchase-related help＇, ＇customer contact＇ through customer satisfaction.

• Journal of the Korean Society for Nondestructive Testing
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• v.25 no.3
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• pp.163-170
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• 2005

A modular Gaussian beam model is developed to simulate some ultrasonic testing configurations where multiple interfaces are involved. A general formulation is given in a modular matrix form to represent the Gaussian beam propagation with multiple interfaces. The ultrasonic transducer fields are modeled by a multi-Gaussian beam model which is formed by superposing 10 single Gaussian beams. The proposed model, referred to as "MMGB" (modular multi-Gaussian beam) model, is then applied to a typical contact and angle beam testing configuration to predict the output signal reflected from the corner of a vertical crack. The resulting expressions given in a modular matrix form are implemented in a personal computer using the MATLAB program. Simulation results are presented and compared with available experimental results.

• Journal of the Korea Society for Simulation
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• v.27 no.2
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• pp.91-100
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• 2018

Recently, the traditional call center, which has an important role as the customer's primary contact point, has been transformed into the omni-channel contact center which supports an additional variety of access channels in addition to phone calls in order to improve customer accessibility and convenience. The omni-channel contact center has agents on each channel which are vital in determining the response rate and waiting time for the customer. In traditional call centers, agents can be assigned to a call based on the characteristics of the call, however in omni-channel contact centers, the characteristics of issues vary and come in through multiple channels, each with their own characteristics, making it difficult to assign the appropriate agent for the issue. Customers must also be processed at the same time, adding an additional layer of complexity to the issue. This paper analyzes and simulates an omni-channel contact center that accommodates email, chat, voice calls and video consultation, and investigates how to optimize the allocation of agents.

• Tribology and Lubricants
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• v.28 no.4
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• pp.173-177
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• 2012

We used contact resonance force microscopy (CRFM) technique to determine the quantitative elastic properties of multiple materials integrated on the sub micrometer scale. The CRFM approach measures the frequencies of an AFM cantilever's first two flexural resonances while in contact with a material. The plain strain modulus of an unknown or test material can be obtained by comparing the resonant spectrum of the test material to that of a reference material. In this study we examined the following bumping materials for flip chip by using copper electrode as a reference material: NiP, Solder (Sn-Au-Cu alloy) and under filled epoxy. Data were analyzed by conventional beam dynamics and contact dynamics. The results showed a good agreement (~15% difference) with corresponding values determined by nanoindentaion. These results provide insight into the use of CRFM methods to attain reliable and accurate measurements of elastic properties of materials on the nanoscale.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.1742-1745
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• 1997

We have developed a highly responsible probing system for inspection of electrical properties of assemble PCB$_{s}$ (printed circuit boards). However, as the duration of the impact occurring between a probe and a solder joint on PCB is very short, it is very difficult to control the harmful peak impact force and the slip motion of the probe to sufficient level only by its vorce feedback control with high gains. To overcome these disadvantages of the prototype, it needs ot obtain some information of the solder joint in advance before the contact. In addition, to guarantee the reliability of the probing task, the probing system is required to measure several points around the probale target point at high speed. There fore, to meet such requirements, we propose a new noncontaet sensor capable of detecting simultaneously position and normal vectors of the multiple points around the probable target point in real time. By using this information, we can prepare a control strategy for stable contact motion on impact. In this paper, we described measuring priniciple, design, and development of the sensor. The effectiveness of the proposed sensor is verified through a series of experiments.s.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.10
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• pp.1465-1469
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• 2013

The resent developed high speed train called HEMU-430X (Highspeed Electric Multiple Unit - 430km/h eXperiment) recorded a 421.4 km/h in Kyoungbu high speed line in Korea. A verity of measurement systems are used to check the performance between pantograph and catenary system. An innovative measurement system is adopted to check the current of catenary wire in the track side during HEMU-430X test running. This paper presents the measurement results of catenary current in kyoungbu high-speed line and describe its utilizing technology in the experimental results of catenary current. In order to analyze field testing results, the current ratio between contact and catenary current have been analyzed by means of Carson-Pollaczek equation. And the current wave forms between catenary and contact wire are presented based on the simulation results.

• The Journal of Korea Robotics Society
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• v.8 no.3
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• pp.186-196
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• 2013

Since its introduction (e.g., [4, 6]), virtual coupling technique has been de facto way to connect a haptic device with a virtual proxy for haptic rendering and control. However, because of the single dependence on spring-damper feedback action, this virtual coupling suffers from the degraded transparency particularly during contact tasks when large device/proxy-forces are involved. In this paper, we propose a novel virtual coupling technique, which, by utilizing passive decomposition, reduces device-proxy position deviation even during the contact tasks while also scaling down (or up) the apparent inertia of the coordinated device-proxy. By doing so, we can significantly improve transparency between multiple degree of freedom (possibly nonlinear) haptic device and virtual proxy. In other to use passive decomposition, disturbance observer of [3] is adopted to estimate human force with some dead-zone modification to avoid "winding-up" force estimation in the presence of device torque saturation. Some preliminary experimental results are also given to illustrate efficacy of the proposed technique.

• Journal of Families and Better Life
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• v.8 no.2
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• pp.119-134
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• 1990

The purpose of this study were to investigate; The contact of housewives with governmental public advertisement about the energy conservation, general tendency about the energy conservation consciousness and behavior. For these purposed, a survey was conducted using questionnaires. Data analysis were conducted from 367 housewives with children in Seoul. Used statistical method were Frequency Distribution, percentile, Mean, one Way Anova, t-test, F-test, Pearson's Correlation, Multiple regression Analysis and Path Analysis. Major findings are as follows. 1) Level of public advertisement contact was low. In contrast to , level of energy conservation consciousness, consciousness change, and behavior was adequately high. 2) Statistically significant difference were found in advertisement contact according to the husband's age , Energy conservation consciousness change according to husband's occupation, and energy conservation behavior according to family life cycle. 3) Energy conservation consciousness changes were increased by advertisement contact. Energy conservation behaviors were increased by conservation consciousness and the degree of conservation consciousness change. 4) Governmental public advertisement about the energy conservation has both direct and indirect effect on the energy conservation behavior. From these finds, the following suggestions are made. Governmental effort about the energy conservation advertisement is needed to be activated. And the implications for the future study was need to incorporate the psychological variables in energy conservation study.