• 한국의류산업학회지
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• 제18권1호
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• pp.38-47
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• 2016

This research analyzes the influence of mobile commerce characteristics on consumer's purchase intention using a theoretical Technology Acceptance Model (TAM) constructed on previous studies and a review of the literature to explain the effect of mobile fashion shopping characteristics on consumer's purchase intention. In constructing structural equation model, Mobile commerce characteristics variables such as 'security', 'enjoyment', and 'personalization' were selected as external variables affecting TAM. A questionnaire was distributed to consumers in their 20's-30's who had purchased fashion products using a mobile shopping channel. Statistical methods of confirmatory factor analysis, correlation, and covariance structural analysis using Amos 19.0 package were employed for the analysis of 453 effective data responses. The results were as follows. First, extended TAM was shown be the appropriate model to explain the influence of mobile commerce characteristics on consumer's purchase intention in mobile fashion shopping. Second, 'security' had a significant positive influence on perceived usefulness (PU), however it affected perceived ease of use (PEOU) negatively. Third, 'enjoyment' had a significant influence only on PEOU, while 'personalization' was found to affect both PEOU and PU significantly. Fourth, PEOU affected PU significantly. Finally, both PEOU and PU had a significant influence on consumer's purchase intention.

• Earthquakes and Structures
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• 제25권3호
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• pp.161-175
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• 2023

High-damping rubber bearings (HDRB) are commonly used as seismic isolation devices to protect civil engineering structures from earthquakes. However, the nonlinear hysteresis characteristics of the HDRB, such as their dependence on material properties and hardening phenomena, make predicting their behavior during earthquakes difficult. This study proposes a hysteretic model that can accurately predicts the behavior of shear deformation considering the nonlinearity when designing the seismic isolation structures using HDR bearings. To model the hysteretic characteristics of the HDR, dynamic loading tests were performed by applying sinusoidal and random waves on scaled-down specimens. The test results show that the nonlinear characteristics of the HDR strongly correlate with the shear strain experienced in the past. Furthermore, when shear deformation occurred above a certain level, the hardening phenomenon, wherein the stiffness increased rapidly, was confirmed. Based on the experimental results, the dynamic characteristics of the HDR, equivalent stiffness, equivalent damping ratio, and strain energy were quantitatively evaluated and analyzed. In this study, an improved bilinear HDR model that can reproduce the dependence on shear deformation and hardening phenomena was developed. Additionally, by proposing an objective parameter-setting procedure based on the experimental results, the model was devised such that similar parameters could be set by anyone. Further, an actual dynamic analysis could be performed by modeling with minimal parameters. The proposed model corresponded with the experimental results and successfully reproduced the mechanical characteristics evaluated from experimental results within an error margin of 10%.

• 한국대기환경학회지
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• 제18권2호
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• pp.85-94
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• 2002

In this study, a 3-dimensional numerical model, has been developed applied for the investigation of combustion characteristics, and used to optimize operating conditions in MSW incinerator, in Gwangju. The model developed in this study has been verified by exacting both the predicted and the measured temperature in combustion chamber which has been operated to provide a reference condition. By predictive results, the Sangmoo incinerator has a good characteristics of combustion and low emission however after burning zone produced incomplete products, also probably because the supply of primary air was not enough. Parametric screening studies have been conducted to study optimal operating conditions. For the optimal combustion characteristics, operating conditions should be adjusted with the waste properties.

• 한국분무공학회지
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• 제12권2호
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• pp.101-107
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• 2007

The purpose of this study is to analyze spray and evaporation characteristics of DME fuel at the high pressure and temperature. For the numerical analysis of dimethyl ether(DME) fuel spray characteristics, hybrid breakup model was applied to the DME spray and its breakup process. In order to obtain experimental results for comparison with the predicted ones, the visualization of the spray evolution process was executed by using a Nd:YAG laser. Also, the numerical investigation was conducted by the two hybrid models for primary and secondary breakup of the DME spray. The primary breakup model was used the Kelvin-Helmholtz(KH) breakup model. In the secondary breakup process, Rayleigh-Taylor(RT) and Drop Deformation Breakup(DDB) model was applied. The results of this study provide the macroscopic characteristics of the spray such as spray tip penetration and cone angle, and prediction accuracy of the two hybrid model.

• Journal of Biosystems Engineering
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• 제19권2호
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• pp.138-147
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• 1994

The stress relaxation and creep characteristics of fruits have usually been fit to an exponential expression based on a generalized Maxwell model and Burger's model. It is known that two to three terms in the expansion of those models are necessary to obtain a satisfactory fit to the rheological characteristics of fruits. Since four to six constants appear in the models, it is very difficult to determine their physical meaning according to the experimental conditions and levels. Therefore in order to ease the comparison of data, this study was conducted to develop the linearized rheological model of the fruit from the previous studies of stress relaxation and creep characteristics of fruits. Stress relaxation and creep characteristics were able to normalize and presented in the linear form of $t/S(t)=K_1+k_2t$ and $t/C(t)={K_1}^{\prime}+{K_2}^{\prime}t$, respectively. It was possible to compare the effects of experimental conditions and levels much easier from the linearized models developed in this study than from the generalized Maxwell model and Burger's model.

• ETRI Journal
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• 제38권6호
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• pp.1031-1041
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• 2016

This paper presents millimeter-wave (mmWave) propagation characteristics and channel model parameters including path loss, delay, and angular properties based on 28 GHz and 38 GHz field measurement data. We conducted measurement campaigns in both outdoor and indoor at the best potential hotspots. In particular, the model parameters are compared to sub-6 GHz parameters, and system design issues are considered for mmWave 5G Giga communications. For path loss modeling, we derived parameters for both the close-in free space model and the alpha-beta-gamma model. For multipath models, we extracted delay and angular dispersion characteristics including clustering results.

• 한국정보시스템학회지:정보시스템연구
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• 제16권3호
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• pp.133-159
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• 2007

The primary purpose of this study is to examine the effects of perceived characteristics on user satisfaction and continuous usage intention in personal communities. We developed a research model based on the literature reviews of personal communities, TAM, perceived risks, and satisfaction. The research model includes perceived playfulness, perceived ease of use, perceived usefulness, and perceived risk as perceived characteristics in personal communities. For validation of this theoretical model, we survey the users of 'Mini-hompy', one of the most popular personal communities in Korea. The research model was empirically verified by structural equation model analysis with data collected from 407 samples. Analysis of the results indicates that perceived ease of use is positively related perceived playfulness and perceived usefulness. Perceived playfulness, perceived ease of use, and perceived risks are significantly related to satisfaction. User's satisfaction has positive relationship with continuous usage intention in personal communities.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2000년도 추계학술대회 논문집
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• pp.246-252
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• 2000

The water quality in Yeongil Bay is getting worse due to the sewage and the waste water from the surrounding industrial complex The study aims to simulate the current system that is necessary to built ecosystem model for the optium water quality control and clarify the correlation of current system characteristics with water quality in Yongil Bay. To clarify the characteristics of coastal water movement system and verify the applicability of the 3-D model, the current system was simulated using 3-D baroclinic model considered tidal current and density effects. As the results of numerical experiments, it is proved the 3-D model is the most appliable on the Yongil Bay where current flows slowly and the flow direction is varied by depths. From the results of simulation considered tidal current only, It am be clearly said the water in Yongil Bay flows in through the surface layer and flows out through the bottom layer. And the fresh water from the Hyongsan river and the heated discharge from POSCO have little effect on the current structure in Yonggil Bay, but have and important effect upon the density structure by diffusion of heat and salt. And the water quality distribution is closely related with the current structure characteristics as well as the tidal residual current system.

• Advances in Computational Design
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• 제4권4호
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• pp.367-379
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• 2019

Multiple Inputs and Multiple Outputs (MIMO) Fuzzy logic model is developed to predict the engine performance and emission characteristics of pongamia pinnata biodiesel with hydrogen injection. Engine performance and emission characteristics such as brake thermal efficiency (BTE), brake specific energy consumption (BSEC), hydrocarbon (HC), carbon monoxide (CO), carbon dioxide ($CO_2$) and nitrous oxides ($NO_X$) were considered. Experimental investigations were carried out by using four stroke single cylinder constant speed compression ignition engine with the rated power of 5.2 kW at variable load conditions. The performance and emission characteristics are measured using an Exhaust gas analyzer, smoke meter, piezoelectric pressure transducer and crank angle encoder for different fuel blends (Diesel, B10, B20 and B30) and engine load conditions. Fuzzy logic model uses triangular and trapezoidal membership function because of its higher predictive accuracy to predict the engine performance and emission characteristics. Computational results clearly demonstrate that, the proposed fuzzy model has produced fewer deviations and has exhibited higher predictive accuracy with acceptable determination correlation coefficients of 0.99136 to 1 with experimental values. The developed fuzzy logic model has produced good correlation between the fuzzy predicted and experimental values. So it is found to be useful for predicting the engine performance and emission characteristics with limited number of available data.

• 대한안전경영과학회:학술대회논문집
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• 대한안전경영과학회 2003년도 춘계학술대회
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• pp.1-5
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• 2003

We purpose a decision model to select the optimal facilities for the Decision Making problems with multiple characteristics(nominal-is-best characteristics, larger-is -better characteristics, smaller- is -better characteristics). Using this model, concept of the loss function is used in this comprehensive method of for select the optimal preferred facilities. To solve the issue on the optimal preferred facilities for multiple characteristics, this study propose the loss function with cross-product terms among the characteristics and derived range of the coefficients of the terms.