• 품질경영학회지
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• 제47권4호
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• pp.755-765
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• 2019

Purpose: Chatbots are widely diffusing across various industries to substitute human manpower in the industry. However as researchers only develop technology that is applied to chatbot, the diffusion is slow in progress. The purpose of this study is to propose useful implications to accelerate diffusion of chatbots across industries by analyzing the perception of customers. To achieve the research purpose this study analyzes causal effect relationship between characteristics of chatbot character, service quality, individual difference, and intention to use chatbot. Methods: This study developed a survey that contains various questionnaires for each construct based on literature review. Data collected through survey was tested for convergent validity and discriminant validity and further analyzed the relationship using PLS-SEM method to verify hypotheses. Results: Trustworthiness of the chatbot character, ease of use, application design, responsiveness, customization, assurance, inertia, and previous experience have significant influence on forming user satisfaction, consumer trust, and intention to use. The others, likability, appropriateness, technology anxiety, and need for interaction were not significant in this research. Conclusion: Although the constructs of the research model was significant in previous literatures, some do not have significant effect on intention to use chatbots. Based on the results, chatbot managers will be able to develop chatbot systems which are more appealing to users and more academic researchers will focus on analyzing user perception and intention.

• Steel and Composite Structures
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• 제23권3호
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• pp.251-261
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• 2017

In this paper, thermal effect on the vibration and stability of initially stressed sandwich plates with functionally graded material (FGM) face sheets is analyzed. Material properties of FGM face sheet are graded continuously in the thickness direction. The variation of FGM properties assumes a simple power law distribution in terms of the volume fractions of the constituents. The governing equations of arbitrarily initially-stressed sandwich plates including the effects of transverse shear deformation and rotary inertia are derived. The initial stress is taken to be a combination of a uniaxial extensional stress and a pure bending stress in the examples. The eigenvalue problems are formed to study the vibration and buckling characteristics of simple supported initially stressed FGM/metal/FGM plates. The effects of volume fraction index, temperature rise, initial stress and layer thickness of metal on the natural frequencies and buckling loads are investigated. The results reveal that the volume fraction index, initial stresses and layer thickness of metal have significant influence on the vibration and stability of sandwich plates with FGM face sheets.

• 설비공학논문집
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• 제28권5호
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• pp.171-177
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• 2016

Plate heat exchangers have been widely used in various fields because of their high heat transfer coefficients, small area of installation, and ease of maintenance compared to other heat exchangers. However, when plate heat exchanger is used for a long time, leak can occur due to inner crack. Therefore, it is important to understand the inner flow characteristics in plate heat exchangers. In this study, the inner flow characteristics and flow rate of plate heat exchanger were evaluated using various flow directions, pin-hole sizes, and Reynolds numbers. In downflow, initially most water flowed to the opposite of the inlet due to distribution region. Then it gradually had a uniform distribution due to chevron configuration. In upflow, it had a uniform flow consistently due to the dominant gravity effect. As the Reynolds number increased, the leak rate was decreased due to the inertia effect regardless of the flow direction.

• 한국공간구조학회:학술대회논문집
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• 한국공간구조학회 2008년도 춘계 학술발표회 논문집
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• pp.74-79
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• 2008

본 논문에서는 유한요소법을 이용하여 저속충격을 받는 복합적층판(Graphite/Epoxy)의 충격과도응답을 조사한다. 판의 대처짐을 고려한 von-Karman 이론에 Mindlin의 전단변형 효과와 회전관성 효과를 포함한 비선형 이론을 도입한다. 과도응답의 수렴은 정적만입실험을 통해 얻은 접촉법칙을 사용하며, 다양한 복합적층판의 두께 변화에 따른 접촉력, 변위응답, 변형률 등을 조사하여 비교 분석한다.

• 한국공작기계학회논문집
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• 제12권4호
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• pp.43-49
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• 2003

This research work has been carried out for finding J-integral in mode II of CFRP(carbon fiber reinforced plastics) laminate plates based on the classical bar theory in dynamic conditions with consideration of the effect of inertia forces, eventually to lead to finding the dynamic inter-layer fracture toughness. Dynamic inter-layer fracture toughness was found by a self-made ENF(End Notched Flexure) experimental apparatus using Split Hopkinson's Bar(SHPB), and also observed the variation of the fracture toughness haying different resin contents and fiber arrangements of CFRP specimen([$0_3^{\circ}/90_3^{\circ}/0_6^{\circ}/90_3^{\circ}/0_3^{\circ}$], [$0_{20}^{\circ}$], [$0_5^{\circ}/90_{10}^{\circ}/0_5^{\circ}$]). As an experimental result, in either cases of quasi-static or dynamic load condition, the critical load and the inter-layer fracture toughness increased sharply depending on the increase of resin contents. Therefore, it could, be concluded that the effect by resin contents is the major factor determining the inter-layer fracture toughness in the CFRP laminate plates.

• Structural Engineering and Mechanics
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• 제16권2호
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• pp.195-217
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• 2003

This paper, which is an extension of a previous work by Viola et al. (2002), deals with the dynamic stability of beams under a triangularly distributed sub-tangential forces when the effect of an elastically restrained end is taken into account. The sub-tangential forces can be realised by a combination of axial and tangential follower forces, that are conservative and non-conservative forces, respectively. The studied beams become unstable in the form of either flutter or divergence, depending on the degree of non-conservativeness of the distributed sub-tangential forces and the stiffness of the elastically restrained end. A non-conservative parameter ${\alpha}$ is introduced to provide all possible combinations of these forces. Problems of this kind are usually, at least in the first approximation, reduced to the analysis of beams according to the Bernoulli-Euler theory if shear deformability and rotational inertia are negligible. The equation governing the system may be derived from the extended form of Hamilton's principle. The stability maps will be obtained from the eigenvalue analysis in order to define the divergence and flutter domain. The passage from divergence to flutter is associated with a noticeable lowering of the critical load. A number of particular cases can be immediately recovered.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2009년도 하계학술발표대회 논문집
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• pp.1220-1225
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• 2009

A manipulator is operated for the motion of mechanical hands or arms. When a cup including liquid inside is shifted by a manipulator, it is important to know how a free surface of the liquid moves. In this study, non dimensional parameters have been found that affect the rise of the free surface in a cup moving with constant acceleration. The non-dimensional parameters are the dimensionless time, the ratio of inertia effect to viscous effect (the Reynolds number), aspect ratio of the liquid inside the cup and the acceleration ratio (the Froude number). Through this study, the height of the free surface rise in a cup has been predicted and the detailed velocities in the liquid have been examined. Generally, the maximum rise of the free surface is dependent on the Reynolds number and Froude number strongly, but on the aspect ratio weakly. However, the influence of the aspect ratio on the maximum rise of the free surface is not negligible in the range of 10 < Re < 100.

• 한국소음진동공학회논문집
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• 제13권7호
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• pp.508-516
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• 2003

The dynamic characteristics of an ell-lubricated, short squeeze film damper (SFD) with a central feeding groove are derived based on a theoretical analysis considering the effect of a groove, and identified experimentally using an Active Magnetic Bearing (AMB) system as an exciter. In order to get the theoretical solution, the fluid film forces of the grooved SFD are analytically derived so that the dynamic coefficients of the SFD can be expressed in terms of its design parameters. For the experimental validation of the analysis, a test rig using an AMB as an exciter is proposed. As an exciter. the AMB represents a mechatronic device to levitate and position the test Journal without any mechanical contact, to generate relative motions of the Journal inside the tested SFD and to measure the generated displacements during experiments with fairly high accuracy. Using this test rig, experiments are extensively conducted with various values of clearance, which Is one of the most important design parameters. in order to investigate its effect on the dynamic characteristics and the performance of the SFD. Damping and Inertia coefficients of the SFD that are experimentally Identified are compared with the analytical results to demonstrate the effectiveness of the applied analysis. It Is also shown that the AMB is an ideal device for tests of SFDs.

• 대한기계학회논문집B
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• 제24권8호
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• pp.1119-1127
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• 2000

Convective heat transfer in a channel filled with porous media has been analyzed in this paper. The two-equation model is applied for the heat transfer analysis with the velocity profile, considering both the inertia and viscous effects. Based on a theoretical solution, the effect of the velocity profile on the convective heat transfer is investigated in detail. The Nusselt number is obtained in terms of the relevant physical parameters, such as the Biot number for the internal heat exchange, the ratio of effective conductivities between the fluid and solid phases, and hydraulic boundary layer thickness. The results indicate that the influence of the velocity profile is characterized within two regimes according to the two parameters, the Biot number and the conductivity ratio between the phases. The decrease in the heat transfer due to the hydraulic boundary layer thickness is 15% at most within a practical range of the pertinent parameters.

• 드라이브 ㆍ 컨트롤
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• 제15권1호
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• pp.1-9
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• 2018

The spool displacement of directional control valve can be considered as the standard signal to measure the bandwidth frequency of a directional control valve. When the spool displacement is not available, the metering-orifice system is implemented in this research as an alternative way of measuring the 90 degrees phase bandwidth frequency of the hydraulic directional control valve. The inertia effect on the transmission line oil induces the phase lead of the valve load pressure when compared with the phase of spool displacement. The capacitance effect of the oil induces the phase lag of the valve load pressure. The phase of the load pressure can be adjusted to be the same as that of the spool displacement by controlling the opening area of the metering orifice. A series of experiments were conducted to verify the effectiveness of the metering orifice. The 90 degrees phase bandwidth frequency measured from the valve load pressure was significantly deviated in some cases from the frequency of the spool displacement. The metering orifice was hard to be applied to measure the -90 degrees phase bandwidth frequency of the high precision.