• Journal of Advanced Marine Engineering and Technology
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• v.22 no.3
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• pp.362-370
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• 1998

Absorption systems require a heat source for working but they have a great merit in that relatively low-temperature and low-quality types of thermal energy such as solar heat and exhaust heat can be effectively utilized as heat source. However details research related to absorbers which have a great effect on performances has been rarely done and thus there has been a strong hope for positive developments to improve their efficiencies. This paper describes absorption experiments made with different inside tube diameters and shapes. The purpose of this study is to acquire basic knowledge about heat and mass transfer in a falling film type absorber with vertical inner tubes. Heat and mass transfer were measured for water vapor absorption into a water/LiBr solution flowing down an absorber of vertical inner tubes. As a result absorption acceleration tube compares bare tube and heat transfer improved by order of insert spring tube corrugated tube grooved tube. And the acceleration that is good provided in inserting spring tube for both sides of heat and mass transfer.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.356-360
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• 2007

Fuel sloshing in a vehicle fuel tank generates a reluctant low frequency noise, called slosh noise. To reduce slosh noise, whilst many approaches have used the Computational Fluid Dynamics method to first identify fuel behavior in a fuel tank, this paper applies the Transfer Path Analysis method. It is to find contribution of each transfer path from noise transfer function, vibration transfer function and acceleration. Then the final goal is to attenuate slosh noise by controlling them. To this aim, two types of models are studied. One is the decoupled model in which some of connection points of the fuel tank with the vehicle underbody are separated. The other is the modified model which is created by changing noise transfer function and acceleration from the original model. The analysis and validation test results show that the transfer path analysis can be an approach to enhancing slosh noise.

• 한국가시화정보학회:학술대회논문집
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• 2004.11a
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• pp.22-25
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• 2004

The present paper investigated the correlation between acoustic pressure and heat transfer augmentation in acoustic fields. The acoustic pressure predicted by numerical work and compared with the augmentation ratio of heat transfer coefficient was experimentally measured. Also, particle image velocimetry(PIV) was used for the visualization of velocity vectors and kinetic energy distribution inside liquid region. For the numerical work, SVS programed with Fortran language and based on a coupled FE-BEM was used. Results of the present study, the acoustic pressure is increased by $60\%$ and the largest augmentation of heat transfer about $28\%$ was measured. Finally, the profiles of acoustic pressure is consistent with that of augmentation of heat transfer. It is concluded that a correlation exists between the acoustic pressure and the heat transfer augmentation.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.8
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• pp.766-770
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• 2007

Fuel sloshing in a vehicle fuel tank generates a reluctant low frequency noise, called slosh noise. To reduce slosh noise, whilst many approaches have used the Computational Fluid Dynamics method to first identify fuel behavior in a fuel tank, this paper applies the Transfer Path Analysis method. It is to find contribution of each transfer path from noise transfer function, vibration transfer function and acceleration. Then the final goal is to attenuate slosh noise by controlling them. To this aim, two types of models are studied. One is the decoupled model in which some of connection points of the fuel tank with the vehicle underbody are separated. The other is the modified model which is created by changing noise transfer function and acceleration from the original model. The analysis and validation test results show that the transfer path analysis can be an approach to enhancing slosh noise.

• Journal of Energy Engineering
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• v.14 no.1
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• pp.30-36
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• 2005

This paper reports the experimental study of the heat transfer characteristics of the wake region behind a cylinder in cross flow. Local heat transfer coefficient was measured from the stagnation point (θ=0°) to 180°, and the variation of Nu in the axial direction along the cylinder was also studied. The results show that the heft transfer rate at the rear (θ=180°) near the duct wall can increase as much as 58% over the 2 dimensional value at the center of the duct. The heat transfer profiles in the wake region also show distinct effects of the aspect ratio and the heat transfer boundary condition.

• The Journal of Society for e-Business Studies
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• v.3 no.1
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• pp.155-173
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• 1998

In this paper we present the development of internet banking and its impact on financial market. The internet banking has been introduced since 1990s, from which customers could obtain most financial services over internet, and will replace with the traditional banks. According to a survey, most of bankers agree that internet will play an important role in banking industry. The internet banking has an enormous impact on the transfer system and banking industry. The transfer system is divided into two-large-value transfer system and small-value transfer system, depending on the size of its transfer amount. The internet banking will enhance the transfer system, especially small-value transfer system. It will reduce the time lag between transaction of service and its payment. However, a congestion or a blockage in a part of network might stop the financial service all over the network, which is called "computer risk". As internet banking develops, banks have incentives to reduce their branches and have to compete with information-business companies which can offer financial EDI.

• Journal of Power Electronics
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• v.9 no.4
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• pp.567-574
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• 2009

A linear transfer function for the output current control of frequency-controlled resonant inverters is proposed in this paper. The circuit of resonant inverters can be transformed into two coupled circuits through the complex phasor transform. The circuits consist of cross-coupled power sources and passive elements. The circuits are used to induce the state space equation, which is transformed into the $4^{th}$ order cross-coupled transfer function. The $4^{th}$ order cross-coupled transfer function is modeled into a $2^{nd}$ order linear transfer function based on a behavior analysis of the pole and zero locations that facilitate a simple and intuitive linear transfer function. The feasibility and validity of the proposed linear transfer function were verified by simulation and experiment.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.53 no.5
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• pp.296-301
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• 2004

The Available Transfer Capability (ATC) is defined as the measure of the transfer capability remaining in the physical transmission network for further commercial activity above already committed uses. Available Transfer Capability (ATC) calculation is a complicated task, which involves the determination I of total transfer capability (TTC), transmission reliability margin (TRM) and capability benefit margin (CBM). As the electrical power industry is restructured and the electrical power exchange is updated per hour, it is important to accurately and rapidly quantify the available transfer capability (ATC) of the transmission system. In ATC calculation,. the existing CPF method is accurate but it has long calculation time. On the contrary, the method using PTDF is fast but it has relatively a considerable error. This paper proposed QFA method, which can reduce calculation time comparing with CPF method and has few errors in ATC calculation. It proved that the method can calculate ATC more fast and accurately in case study using IEEE 24 bus RTS.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.32B no.9
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• pp.1162-1170
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• 1995

In this paper, we present a message transfer scheme for efficient message passing in the hierarchically structured multiprocessor computer SPAX(Scalable Parallel Architecture computer based on X-bar network). The message transfer scheme provides interface not only with operating system but also with end users. In order to transfer two types of control message and data message efficiently, it supports both of memory-mapped transfer and DMA-based transfer. Dual-port RAMs are used as message buffers, and control and status registers provide efficient programming interface. Interlaced parity scheme is adopted for error control. If any error is detected at receiving node, errored packet is resent by sender according to retry mechanism. In conjunction with retry mechanism, watchdog timers are used to protect infinite waiting and repeated retry. The proposed message transfer scheme can be applied to input/output nodes and communication connection nodes as well as processing nodes in the SPAX.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.1
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• pp.61-67
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• 2003

This paper presents a power transfer capability calculation algorithm considering initial maximum power transfer capability. In this method initial maximum power transfer capability is calculated first. Then, the initial value of active power outputs of generators is gotten for power transfer capability calculation. The proposed method is applied to IEEE-24 Reliability Test System and the results show the effectiveness of the method.