• Journal of the Korean Institute of Gas
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• v.28 no.1
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• pp.59-64
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• 2024

In this study, we conducted research on a miniaturized transmission system suitable for ultra-compact electric vehicles, such as electric arts or small electric cars. While conventional electric vehicles eliminate multi-gear transmissions and control motor output or secure initial driving force through reducers, in vehicles like electric karts or compact electric cars, which have relatively small battery capacities, the driving range can be reduced or the motor can be stressed epending on the loading state. Therefore, in this study, we developed a low stage ratio 0.625 and high stage ratio 1.6 a two-stage transmission system that can change gears as needed, considering factors such as slope conditions and loading status, by applying the continuously variable transmission (CVT) mechanism. Based on the selected gear ratios, we designed the transmission and created a test rig to verify the power transmission efficiency of the developed transmission. Using the test rig, we varied the rotational speed and load of the transmission to confirm its power transmission characteristics and also examined the heat generation characteristics during shifting and operation. As a result, developed a two-stage transmission with a CVT structure.

• Journal of the Korean Society for Nondestructive Testing
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• v.33 no.2
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• pp.129-137
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• 2013

A force calibration of a nanoindenter and a 3D morphology observation of indenters were carried out in this study. A microbalance calibrated with standard weights was used for measuring the loads generated by a nanoindenter. The indentation load could be calibrated from the ratio of measured and generated loads and the first contact load also could be detected from the microbalance data. By analyzing atomic force microscopy images of two indenters, curvature radii of apexes were determined by $19.71{\pm}3.03$ and $1043.94{\pm}50.91$ nm, respectively, for the nearly new indenter A and the severly worn indenter B. Corresponding bluntness depths were estimated by 1.22 and 64.56 nm for the both indenters by overlapping their profiles on the perfect pyramidal shape. In addition, nanoindentation curves obtained from a fused silica reference material with the both indenters showed a depth difference corresponding to the bluntness depth difference along the indentation depth axis. By shifting amounts of the bluntness depths along the horizontal axis, whole nanoindentation curves overlapped on themselves and resulted in nanohardness values consistent within 1.11 % without considering the complex indenter area function of each indenter.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.4C
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• pp.163-174
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• 2009

Mechanical device using the load cell or strain gage sensor can be influenced by tempearute changes because temperature change can cause a shift in the load cell or straing gage output at zero loading. In this paper, micro cone penetrometers with 1~7mm in diameter, are developed by using an optical fiber sensor (FBG: Fiber Bragg Grating) to compensate the continous temperature change during cone penetration test. Note the temperature compensated method using optical fiber sensor which has hair-size in diameter, and is not affected by environmental conditions because the measured data is the wavelength shifting of the light instead of the intensity of the electric voltage. Temperature effect test shows that the output voltage of strain gage changes and increases with an increase in the temperature. A developed FBG cone penetrometer, however, achieves excellent temperature compensation during penetration, and produces continuous change of underground temperature. In addition, the temperature compensated FBG cone shows the excellent sensitivity and detects the interface of the layered soils with higher resolution. This study demonstrates that the fiber optic sensor renders the possibility of the ultra small size cone and the new fiber optic cone may produce more reliable temperature compensated tip resistance.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.7
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• pp.1124-1128
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• 2021

As regulations of emissions from ships become more stringent, electric propulsion systems have been increasingly used to solve this problem in vessels ranging from large merchant ships to small and medium-sized ships. Methods for improving the efficiency of the electric propulsion system include the improvement of power sources; the use of a system linked to environmentally friendly power sources, such as batteries, fuel cells, and solar power; and the development of hardware and control methodology for rectifiers, power conversion devices, and propulsion motors. The method using a phase-shifting transformer with diodes has been widely used for rectification. Power semiconductor devices with grid connection to an environmentally friendly power source using DC distribution, a variable speed power source, and the application of small and medium-sized electric propulsion systems have been developed. Accordingly, the demand for active front-end (AFE) rectifiers is increasing. In this study, a method using a neural network rather than a conventional proportional-integral controller was proposed to control the AFE rectifier. Tested controller data were used to design a neural network controller trained through MATLAB/Simulink. The neural network controller was applied to a rectification system designed using PSIM software. The results indicated the effectiveness of improving the waveform and power factor DC output stage according to the load variation. The proposed system can be applied as a rectification system for small and medium-sized environmentally friendly ships.

• Asia Marketing Journal
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• v.15 no.4
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• pp.103-129
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• 2014

Differentiated positioning becomes increasingly difficult when brand salience weakens. Also, the daily increase in new media use and information load has led to a social climate that regards advertising stimuli as spamming. For these reasons, the focus of advertisement-related communication is shifting from persuading consumers through the direct delivery of information to an emphasis on appealing to their emotions using matching stimuli to enhance persuasion effects. Recently, both academia and industry have increasingly shown an interest in storytelling methods that can generate positive emotional responses and attitude changes by arousing consumers' narrative processing. The purpose of storytelling is to elicit consumers' emotional experience to meet the objectives of advertisement producers. Therefore, the most important requirement for storytelling in advertising is that it evokes consumers' sympathy for the main character in the advertisement. This does not involve advertisements directly persuading consumers, but rather, consumers themselves finding an answer through the advertisement's story. Thus, consumers have an indirect experience regarding the product features and usage through empathy with the advertisement's main character. In this study, we took the results of a precedent study as the starting point, according to which consumers' emotional response can be altered depending on the storytelling methods adopted for storytelling ads. Previous studies have reported that drama-type and vignette-type storytelling methods have a considerably different impact on the emotional responses of advertising audiences, due to their different structural characteristics. Thus, this study aims to verify that emotional response aroused by different types of advertisement storytelling (drama ads vs. vignette ads) can be controlled by the socio-psychological gender difference of advertising audiences and that the interaction effects between the socio-psychological gender differences of the audience and the gender stereotype of emotions to which advertisements appeal can exert an influence on emotional responses to types of storytelling in advertising. To achieve this, an experiment was conducted employing a between-group design consisting of 2 (storytelling type: drama ads vs. vignette ads) × 2 (socio-psychological gender of the audience: masculinity vs. femininity) × 2 (advertising appeal emotion type: male stereotype emotion vs. female stereotype emotion). The experiment revealed that the femininity group displayed a strong and consistent empathy for drama ads regardless of whether the ads appealed to masculine or feminine emotions, whereas the masculinity group displayed a stronger empathy for drama ads appealing to the emotional types matching its own gender as well as for vignette ads. The theoretical contribution of this study is significant in that it sheds light on the controllability of the audiences' emotional responses to advertisement storytelling depending on their socio-psychological gender and gender stereotype of emotions appealed to through advertising. Specifically, its considerable practical contribution consists in easing unnecessary creative constraints by comprehensively analyzing essential advertising strategic factors such as the target consumers' gender and the objective of the advertisement, in contrast to the oversimplified view of previous studies that considered emotional responses to storytelling ads were determined by the different types of production techniques used. This study revealed that emotional response to advertisement storytelling varies depending on the target gender of and emotion type appealed to by the advertisement. This suggests that an understanding of the targeted gender is necessary prior to producing an advertisement and that in deciding on an advertisement storytelling type, strategic attention should be directed to the advertisement's appeal concept or emotion type. Thus, it is safe to use drama-type storytelling that expresses masculine emotions (ex. fun, happy, encouraged) when the advertisement target, like Bacchus, includes both men and women. For brands and advertisements targeting only women (ex. female clothes), it is more effective to use a drama-type storytelling method that expresses feminine emotions (lovely, romantic, sad). The drama method can be still more effective than the vignette when women are the main target and a masculine concept-based creative is to be produced. However, when male consumers are targeted and the brand concept or advertisement concept is focused on feminine emotions (ex. romantic), vignette ads can more effectively induce empathy than drama ads.