• Journal of Electrical Engineering and Technology
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• v.4 no.4
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• pp.499-509
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• 2009

Electric vehicles (EV) are developing fast during this decade due to drastic issues on the protection of environment and the shortage of energy sources, so new technologies allow the development of electric vehicles (EV) by means of electric motors associated with static converters. The proposed propulsion system consists of two induction motors (IM) that ensure the drive of the two back driving wheels. The electronic differential system ensures the robust control of the vehicle behavior on the road. It also allows controlling, independently, every driving wheel to turn at different speeds in any curve. This paper presents the study of an hybrid Fuzzy-sliding mode control (SMC) strategy for the electric vehicle driving wheels, stability improvement, in which the fuzzy logic system replace the discontinuous control action of the classical SMC law. Our electric vehicle fuzzy-sliding mode control's simulated in Matlab SIMULINK environment, the results obtained present the efficiency of the proposed control with no overshoot, the rising time is perfected with good disturbances rejections comparing with the classical control law.

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.3
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• pp.351-359
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• 2010

Bi-fuel system in a spark ignition engine (SIE) is a rising phenomena in today's automobile technology. In a gasoline driven vehicle, alternatively adoption of compressed natural gas (CNG) could be used as a potential substitute to meet the energy requirement and this is possible by some minor changes in the hardware of the existing engine. Gasoline engine is widely used in the passenger cars, light, medium and heavy duty vehicles but the consumption status of the petroleum is decreasing worldwide and at the same time environmental pollution from automobiles is seriously establishes as a threat for every nation in respect to global warming and climate changes. Now-a-days most vehicles operate using CNG for its popularity stems, clean burning properties and cost effective solution compared to other alternative fuels. It refers as a good gaseous fuel because of its high octane number and self ignition temperature. Though the power output is slightly lesser than the gasoline fuel; its thermal efficiency is better than the gasoline for the same SIE. The research paper highlights the reduction of CO, reasonable outcomes of HC emissions with minor increase in $NO_x$ emissions compared with the gasoline fuel to bi-fuel mode in the SIE that meets the emission challenges.

• Journal of the Korea Furniture Society
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• v.20 no.6
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• pp.590-598
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• 2009

The study of Lurelle Van Arsdale Guild (1898-1986)'s vanity table and stool in the Cooper-Hewitt National Design Museum is essential to understand how the stylistic change was made on industrial design in the 1930s caused by economic necessity. The vanity furniture expresses in such relatively inexpensive image transformations that would attract new customers in the Depression. The objects are donated from a collector and became one of CHM's collections in 1997. In curatorial file, other than the designer's and manufacturer's names there is nothing specified for these objects. Therefore, this study is aimed for researching the exact date for these valuable objects for understanding American Art Deco furniture in the 1930s. Moreover, studying social aspect of these objects gives clear vision for the background. Especially, the History of American Standard (Rodengen, 1999) gives great over view to the history of the manufacturer, C. F. Church Company. The record in Fortune of 1934 suggests the designer, Lurelle Guild's position among other industrial designers at that time. And Profoundly, the objects were assigned design patents. Therefore, the vanity furniture set in the CHM was a significant symbol of early modernism rising from functional areas after the Depression.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.12
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• pp.9-20
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• 2012

This paper proposes the efficiency optimization control of interior permanent magnet synchronous motor(IPMSM) drive using series connected-fuzzy neural network PI(SC-FNPI) controller. The PI controller is generally used to control IPMSM drive in industrial field. However, the PI controller has problem which is falling control performance about parameter variation such as command speed, load torque and inertia due to fixed gain of PI controller. Therefore, to improve performance of PI controller, this paper proposes SC-FNPI controller adjusted input of PI controller by FNN controller according to operating conditions. Also, this paper proposes efficiency optimization control which is improving efficiency with minimize loss. The SC-FNPI controller proposed in this paper is compared control performance with conventional FNN and PI controller about command speed, load torque and inertia variation. And the efficiency optimization control is compared with $i_d=0$ control about loss and efficiency. The SC-FNPI controller proposed in this paper shows more excellent control performance for rising time, overshoot and steady-state error. Also efficiency optimization control is increased efficiency by reducing loss.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.3
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• pp.101-113
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• 2020

The study aims to investigate the existence of overconfidence bias in Vietnam, Thailand, and Singapore. This paper focuses on the Vietnam Stock Market and other two countries of ASEAN, namely Singapore and Thailand. Data was collected over the period from January 1, 2014 to December 31, 2018, daily returns for each of the securities. This paper uses the time series method, namely ADF test, Granger Causality and VAR approach to find evidences of the overconfidence effect in Vietnam in relation to some ASEAN markets. The results show similarities between the observed countries with slight variations, with focus on Vietnam market. In general concrete evidences of overconfidence were found in both Vietnamese and Singaporean markets, in which Singaporean investors show higher degree of overconfidence than Vietnamese investors. Overconfidence is not as clear in Thai market, however a direct causal link from increased returns to increased investor confidence was found. From the model deployed in the paper, there are reasons to conclude that Thai investors are under-confident. The findings of the study shed lights into the existence of overconfidence bias in Vietnam, Thailand, and Singapore on a comparative basis, provide more insights and implications for future research in this new and rising field of research.

• Journal of the Korean Society of Propulsion Engineers
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• v.8 no.2
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• pp.73-84
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• 2004

In general, static firing test is conducted before flight in order to obtain data such as thrust. pressure, temperature and strain, which show the characteristics of rocket motors. But the measured thrust of the obtained data is especially distorted by the effects of dynamic characteristics of thrust stand so that it is difficult for us to determine the exact value of peak thrust and rising time etc., which represent the performance of rocket motor. This paper, therefore. verified the causes of distortion of measured thrust, and proposed the theoretical method to estimate the true thrust from the distorted thrust. And also the proposed method was applied to virtual thrust stand using computer simulation, and showed good result. As a result of that, the proposed method was proven to be valid and applicable to estimate distorted thrust.

• Structural Engineering and Mechanics
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• v.64 no.1
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• pp.121-133
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• 2017

This paper proposes an analytical solution method for free vibration of curved functionally graded (FG) nonlocal beam supposed to different thermal loadings, by considering porosity distribution via nonlocal elasticity theory for the first time. Material properties of curved FG beam are assumed to be temperature-dependent. Thermo-mechanical properties of porous FG curved beam are supposed to vary through the thickness direction of beam and are assumed to be temperature-dependent. Since variation of pores along the thickness direction influences the mechanical and physical properties, porosity play a key role in the mechanical response of curved FG structures. The rule of power-law is modified to consider influence of porosity according to even distribution. The governing equations of curved FG porous nanobeam under temperature field are derived via the energy method based on Timoshenko beam theory. An analytical Navier solution procedure is used to achieve the natural frequencies of porous FG curved nanobeam supposed to thermal loadings with simply supported boundary condition. The results for simpler states are confirmed with known data in the literature. The effects of various parameters such as nonlocality, porosity volume fractions, type of temperature rising, gradient index, opening angle and aspect ratio of curved FG porous nanobeam on the natural frequency are successfully discussed. It is concluded that these parameters play key roles on the dynamic behavior of porous FG curved nanobeam. Presented numerical results can serve as benchmarks for future analyses of curve FG nanobeam with porosity phases.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.51
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• pp.133-158
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• 2011

The purpose of this study is to analyze one of CIETEC(China International Economic and Trade Arbitration Commission) Award on the dispute arising from Cotton Sale Contact which deals with damages and reduction of the price. Especially this case focused on the effect of reduction of the price to damages. The purpose of damages is to place the aggrieved party in as good a position as if the other party had properly performed the contract. So court costs and attorney's fee should be regarded as the loss, because these are caused by consequence of the breach which is recoverable. With the same reason, overpaid taxes should also regard as the loss. It is not impossible, however, to claim both damages and reduction of the price for same loss at the same time. It means buyer could not claim damages for the same loss, once he already claimed reduction of the price. So Korean companies should consider which remedy is proper to himself under the circumstances. He should choose reduction of the price when market price is down. In case of rising market price, he should consider follows: first, it is better to choose damages based on current price(Art.76), if upswing of non-conformity price is higher then upswing of market price. Second, it is better to choose general rule for measuring damages(Art.74), if upswing of market price is higher then upswing of non-conformity price.

• Korean Journal of Human Ecology
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• v.17 no.1
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• pp.105-114
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• 2008

This study aims on observing the social recognition and its aspects for men taking care of their outer appearances at current point where men are rapidly rising as the main consumer in the beauty industry while their interest for outer appearances are increasing. Therefore, we observed the overall trend and changes in social recognition for male looks by analyzing the contents of articles in fashion magazines that play the critical role of spreading the trend while suggesting and delivering the diverse trend changes to the public to correspond to the individual and concrete demands of certain class segmented into gender, age, hobby, and more. As a result, articles related to outer appearances were divided into fashion, cosmetic and skin, hair and scalp, body figure care, cosmetic surgery, and others, and among them, fashion category took up the highest ratio. Also, articles related to outer appearances increased even more according to the change in time, where articles related to fashion and hair increased while articles of other categories decreased.

• Journal of Information Technology and Architecture
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• v.11 no.1
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• pp.75-80
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• 2014

At the time the interest and love of the Korean professional baseball is increasing, the need for effective recruiting method rising. Recruiting existing methods were scheme based on expert evaluation, to obtain the players of each team. However, the existing method does not reflect only objective rating but also subjective way of school tie and delays are effect. Therefore the conventional method could not be the efficient. Therefore this paper analyze Korea baseball player's efficiency based on entire team and each team by using DEA (Data Envelopment Analysis) method, and use this efficiency to discuss effective way of recruiting players. Finally, the validity of experiment is confirmed by the matters of actual sell of players who are scouted by experiment.