• Journal of computational fluids engineering
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• v.20 no.3
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• pp.62-69
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• 2015

Pressure change inside cabin as well as in tunnel has been calculated to assess the passenger pressure comfort of high-speed train. $C-STA^{TM}$, a CFD program based on axi-symmetric Navier-Stokes equation and Roe's FDS has been used to simulate the pressure change in tunnel during a high-speed train passing through it. To present the relative motion between the train and the tunnel, a modified patched grid scheme based on the structured grid system has been employed. The simulation program has been validated by comparing the simulation results with field measurements. Extensive parametric study has been conducted for various train speed, tunnel cross-sectional area and tunnel length to the pressure change in cabin. KTX-Sancheon(KTX2) high-speed train has been chosen for simulation and the train speed have been varied from 200 km/h to 375 km/h. The tunnel length has been varied from 300 m to 7.5 km and tunnel area from $50m^2$ to $120m^2$. Total 504 simulations have been conducted varying the parameters. Based on the database produced from the parametric simulations, minimum tunnel cross-sectional area has been surveyed for various train speeds based on Korean regulation on pressure change in cabin.

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.361-365
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• 2005

Since the fuel cell uses the hydrogen for its fuel. it has no emission and higher efficiency than an internal combustion engine. Also fuel cell is much quieter than engine generator and generates heat much less than engine generator. So it has advantage of Army's 'si lent watch' capability and the ability to operate undetected by the enemy. The fuel cell hybrid system combines a fuel cell power system with an ESS. The ESS (e.g., batteries or ultracapacitors) reduces the fuel cell's peak power and transient response requirements. It allows the fuel cell to operate more efficiently and recovery of vehicle energy during deceleration. The battery has high energy density, so it has the advantage regarding driving distance. However, it has a disadvantage considering dynamic characteristic because of low power density. One other hand. the ultracapacitor has higher power density, so it can handle sudden change or discharge of required power. Yet. it has lower energy density. so it will be bigger and heavier than the battery when it has the same energy. This paper proposes the power management strategy for multi-power source fuel cell hybrid system. which is applied with the merits of both battery and ultra capacitor by using both of them simultaneous.

• Advances in nano research
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• v.3 no.3
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• pp.143-168
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• 2015

Initiation of crack and its growth simulation requires accurate model of traction - separation law. Accurate modeling of traction-separation law remains always a great challenge. Atomistic simulations based prediction has great potential in arriving at accurate traction-separation law. The present paper is aimed at establishing a method to address the above problem. A method for traction-separation law prediction via utilizing atomistic simulations data has been proposed. In this direction, firstly, a simpler approach of common neighbor analysis (CNA) for the prediction of crack growth has been proposed and results have been compared with previously used approach of threshold potential energy. Next, a scheme for prediction of crack speed has been demonstrated based on the stable crack growth criteria. Also, an algorithm has been proposed that utilizes a variable relaxation time period for the computation of crack growth, accurate stress behavior, and traction-separation atomistic law. An understanding has been established for the generation of smoother traction-separation law (including the effect of free surface) from a huge amount of raw atomistic data. A new curve fit has also been proposed for predicting traction-separation data generated from the molecular dynamics simulations. The proposed traction-separation law has also been compared with the polynomial and exponential model used earlier for the prediction of traction-separation law for the bulk materials.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.3
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• pp.303-310
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• 2020

The study aims to evaluate the factors affecting the intention to use digital banking in Vietnam. Multivariate data analysis techniques (Cronbach's Alpha test, Confirmatory Factor Analysis, Structure equation model) are used for the survey data collected from 201 customers who have access to digital banking. The analysis results show that: (1) attitude towards the service, perceived usefulness has a positive impacts on the intention to use; (2) convenience does not affect the intention to use digital banking services; (3) perceived usefulness factor has a positive effect on the attitude towards the service; (4) The perceived risk has a negative impact on attitude towards the service; (5) trust has no effect on the attitude towards the service; (6) ease of use has a positive impact on perceived usefulness; (7) trust has a positive effect on perceived risk. From the results of this study, perceived usefulness has a positive effect on attitude and intention to use the service. Therefore, it is necessary to enhance the sense of the usefulness of customers through media advertising and consulting so that customers fully understand the benefits brought about by using digital banking services. Perceived risk has a negative impact on attitude towards the service.

• The Journal of Asian Finance, Economics and Business
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• v.5 no.2
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• pp.43-51
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• 2018

We study the impact of economic policy uncertainty (EPU) of Asian four countries such as Korea, Japan, Hong Kong, and China on housing market returns in Korea. Also, we document the relationship between the EPU index of those four countries and the housing market including macroeconomic indicators in Korea. The EPU index of those four countries has significantly a negative effect on the housing purchase price index, housing lease price index in Korea. The EPU index in Korea and Japan has significantly a negative effect on the CPI. The EPU index in only Japan has significantly a negative effect on the PPI. The EPU index in Hong Kong and Korea has significantly a negative effect but the EPU index in China significantly has a positive effect on the stock price index in construction industry. The EPU index in only Korea has significantly a negative effect the stock price index in banking industry. This study shows the EPU index of the Korea has the negative relationships on the housing market economy rather than other countries by VECM. And this study has an important evidence of the spillover of several macroeconomic indicators in Korea for the EPU index of the Asian four countries.

• Journal of Sasang Constitutional Medicine
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• v.16 no.1
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• pp.37-43
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• 2004

1. Purpose Between "HamsanSachon Dongyi Suse Bowon GaboGubon" and ShinChukbon "Dongyi Suse Bowon", there are many differences and changes of contents. It is due to the changes of Dong-Mu's recognition about symptoms. Therefore, this study will aim to compare constitutional symptoms of Soyangin's with Taeumin's about sweating and pissing. 2. Methods In ShinChukbon "Dongyi Suse Bowon", I found contents about sweating and pissing, and compared constitutional symptoms of Soyangin's with Taeumin's about sweating and pissing. 3. Result and Conclusion 1) In ShinChukbon "Dongyi Suse Bowon", I concluded that Soyangin who has interior disease may piss lesser than Soyangin who has ordinary symptoms. Otherwise, Taeumin who has interior disease may piss more than Taeumin who has ordinary symptoms. 2) In ShinChukbon "Dongyi Suse Bowon", I concluded that Soyangin who has interior disease sweats more than Soyangin who has ordinary symptoms. Otherwise, Taeumin who has interior disease may sweat lesser than Taeumin who has ordinary symptoms. 3) The results of this study was to compare Soyangin with Taeumin on ShinChukbon "Dongyi Suse Bowon". More studies are demanded in other writings of Dong-Mu's.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.5
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• pp.437-443
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• 2004

Aperture has been employed on the ground plane in the hairpin resonator. Aperture has been fabricated by etching the part of the ground effected coupling coefficient and then quality factor of hairpin resonator has been increased. When the hairpin oscillator using aperture has been compared with the conventional hairpin oscillator using microstrip, it has been improved the phase noise about 19 ㏈c @100 ㎑. As a result of PBG connecting to the output of the employing aperture hairpin oscillator, the second and third harmonics are suppressed. In this paper, oscillator has been designed and fabricated in operating 5.8 ㎓ band. The output power has been obtained 0,67 ㏈m and the second harmonic has been suppressed about -53,67 ㏈c.

• Journal of Physiology & Pathology in Korean Medicine
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• v.17 no.3
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• pp.611-616
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• 2003

Through the whole period of the twentieth century, Chinese Traditional Medicine has been affected by the political and cultural changes of Chinese society. Before the 1949 Communist Revolution, Chinese Traditional Medicine was regarded as a dark past which should be cleared off. But Chinese Traditional Medicine has been reevaluated as a national medicine and spreaded quickly since the 1949 Communist Revolution. Moreover, 'the bare foot doctor' who received short term training appeared during the Cultural Revolution. It enhanced the status of Chinese Traditional Medicine. At the same time, it was estimated as a model of the self-reliant development of Third World countries. But the direction of development of Chinese Traditional Medicine was changed again recently. Chinese government has adapted the open-economy policy since the late 1970s. Accordingly Chinese Traditional Medicine also has been changed. Nowadays it pursues the professional development strategy. This paper inquired the following research questions. First, what kind of historical changes in the development strategy of Chinese Traditional Medicine has happened? Second, how much Chinese Traditional Medicine has accomplished the professionalization? Third, what kind of problems Chinese Traditional Medicine has met in the process of professionalization? Finally, why Chinese Traditional Medicine has adapted the professional development strategy?

• Coupled systems mechanics
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• v.3 no.3
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• pp.247-265
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• 2014

This article discusses the dynamic response of Bernoulli-Euler straight beam with angular elastic supports subjected to moving load with variable velocity. A new engineering approach for determination of the dynamic effect from the moving load on the stressed and strained state of the beam has been developed. A dynamic coefficient, a ratio of the dynamic to the static deflection of the beam, has been defined on the base of an infinite geometrical absolutely summable series. Generalization of the R. Willis' equation has been carried out: generalized boundary conditions have been introduced; the generalized elastic curve's equation on the base of infinite trigonometric series method has been obtained; the forces of inertia from normal and Coriolis accelerations and reduced beam mass have been taken into account. The influence of the boundary conditions and kinematic characteristics of the moving load on the dynamic coefficient has been investigated. As a result, the dynamic stressed and strained state has been obtained as a multiplication of the static one with the dynamic coefficient. The developed approach has been compared with a finite element one for a concrete engineering case and thus its authenticity has been proved.

• Korean Journal of Agricultural Science
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• v.44 no.2
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• pp.181-187
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• 2017

The use of practical management factors to maximize pig health improvement cannot guarantee freedom from diseases. Moreover, because of health safety concerns, the use of antibiotics has been restricted in livestock, including pigs. Therefore, the swine industry has been looking for various alternatives to antibiotics to improve pig's health and performance. Clay is a dietary factor generally accepted for improving pig health. It is a naturally occurring material and is primarily composed of fine-grained minerals. It has a specific structure with polar attraction. Because of this structure, clay has the ability to lose or gain water reversibly. In addition, clay has beneficial physiological activities. First, clay has anti-diarrheic and antibacterial effects by penetrating the cell wall of bacteria or inhibiting their metabolism. Second, it can protect the intestinal tract by absorbing toxins, bacteria, or even viruses. When added to the diet, clay has also been known to bind some mycotoxins, which are toxic secondary metabolites produced by fungi, namely in cereal grains. Those beneficial effects of clay can improve pigs' health and performance by reducing pathogenic bacteria, especially pathogenic Escherichia coli, in the intestinal tract. Therefore, it is suggested that clay has a remarkable potential as an antibiotics alternative.