• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.18 no.2
• /
• pp.103-111
• /
• 2006

To optimize the ventilation and smoke control systems in subway equipped with platform screen door, the technology to analyze the unsteady tunnel flow caused by running of train should be developed. The development of model experiment and numerical analysis technique with relation to unsteady flow of subway were presented. The pressure and air velocity changes in 1/20-scaling experiment unit were measured and results were comparied to those of 3-D unsteady numerical analysis applied with sharp interface method. The experimental and numerical results were quantitatively similar and it would be reasonable to apply sharp interface method to analyze the unsteady flow in subway equipped with platform screen door.

• Computational Structural Engineering
• /
• v.8 no.3
• /
• pp.75-78
• /
• 1995

The boundary element analysis has been attempted for investigating the singular stress at the interface edge of infinitely layered structure. The subdomain technique has been employed and the analysis model has been divided into two subdomains, which are respectively homogeneous elastic zones. The boundary element equation has been formulated using the equilibrium and continuity conditions at the common interface. The numerical results of example problem has been presented.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2007.04a
• /
• pp.471-474
• /
• 2007

A domain/boundary decomposition technique is applied to carry out efficient finite element analyses of 3-D contact problems. Appropriate penalty functions are selected for connecting an interface and contact interfaces with neighboring subdomains that satisfy continuity constraints. As a consequence, all the effective stiffness matrices have positive definiteness, and computational efficiency can be improved to a considerable degree. If necessary, any complex-shaped 3-D domain can be divided into several simple-shaped subdomains without considering the conformity of meshes along the interface. With a set of numerical examples, the basic characteristics of computational efficiency are investigated carefully.

• The Transactions of the Korean Institute of Electrical Engineers
• /
• v.38 no.1
• /
• pp.35-42
• /
• 1989

Electrical properties of both a monolayer at the air/water interface and Langmuir-Blodgett films sandwiched between aluminum electrodes are studied using a current-measuring technique. A change in induced charges on an electrode suspended in the air was measured in combination with the surface area isotherm in the electrical measurement of the monolayer. A change in induced charges on an electrode is measured while heating the sample in the electrical measurement of the LB films. From both measurements, we elucidated that a spontaneous polarization plays very important role in the electrical properties of both a monolayer at the air/water interface and LB films sandwiched between aluminum electrodes.

• Proceedings of the Korean Society of Broadcast Engineers Conference
• /
• 1999.06a
• /
• pp.63.1-68
• /
• 1999

MPEG-2 transcoding scheme is proposed as scalable transmission system for a video-on-demand system is described. In this system video contents encoded by MPEG-2 are transmitted to receiver terminals via communication lines that have different bit rate. A transcoding technique that directly converts a bit stream encoded by MPEG-2 into a lower coding rate stream without decoding is proposed. The transcoder called Trampeg includes size reduction and frame drop approach. The experimental results show that an MPEG-2 stream of 0 Mbps is able to be transcoded into a stream of 1.5 Mbps-300 Kbps.

• Proceedings of the KSPS conference
• /
• 2005.11a
• /
• pp.67-70
• /
• 2005

Voice conversion (VC) is a technique for modifying the speech signal of a source speaker so that it sounds as if it is spoken by a target speaker. Most previous VC approaches used a linear transformation function based on GMM to convert the source spectral envelope to the target spectral envelope. In this paper, we propose several nonlinear GMM-based transformation functions in an attempt to deal with the over-smoothing effect of linear transformation. In order to obtain high-quality modifications of speech signals our VC system is implemented using the Harmonic plus Noise Model (HNM)analysis/synthesis framework. Experimental results are reported on the English corpus, MOCHA-TlMlT.

• Proceedings of the IEEK Conference
• /
• 1998.06a
• /
• pp.737-740
• /
• 1998

Under the worldwide booming internet environment, there has been increasing demand for various multimedia services. Especially the demand for effective video services has been rapidly increased. In this paper, we describe the implementation of video service system for internet use based on H/263 video compression technique and UDP socket on the TCP/IP environment. In addition, by using the plug-in-play technique, the implemented system improved user interface for correct retrieval and easy usage.

• Proceedings of the KIPE Conference
• /
• 1999.07a
• /
• pp.270-273
• /
• 1999

This paper describes the characteristics of two methods about providing information needed for propulsion device control in train. The one is to use new way using the communication network for transmission of control information, the other is traditional way using hardwire connection. And this paper describes the communication interface technique between TCMS(Train Control and Monitoring System) and VVVF inverter system with LonWorks network adapted to SMG line 6 which has been developed. With this technique, an inertia load test carried out for the traction control environment and it is expecting a field test at SMG line 6.

• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 1999.10c
• /
• pp.618-624
• /
• 1999

For many soft ground embankment projects , instrumentation programs for stability and settlement management is being essential . This usually leads to generate large volume of data, which can be used for further research. Database technique is most effective method for data management . Data produced by soft ground embankment instrumentation can not be used by itself but must be reproduced using geotechnical analysis technique. In this study, a intelligent database system for softground called IDSIM was developed to examine applicability intellgent database. . The IDSIM analysis instrumentation data automatically and present results by Web/DB interface successfully.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.20 no.8
• /
• pp.2611-2625
• /
• 1996

A numerical method on multi-block technique by Bi-CGSTAB(Bi-Conjugate Gradient STABilized) solver has been proposed. The present multi-block technique can reduce the numerical manipulation greatly because the common regions at the interface of each block are not necessary. In order to test the computational performance of present multi-block technique, the flow characteristics in a T type duct system and a N type duct system have been investigated by three kinds of methods such as the single-block method, the previous multi-block technique and the multi-block technique with Bi-CGSTAB solver. The results indicated that the required CPU time by present multi block technique was shorter than that of other two numerical methods and the convergency history was shown very stable at the present multi-block technique.