• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.27 no.9C
• /
• pp.842-852
• /
• 2002

The fast advance in the VoIP technologies gives a rich opportunity to create different kind of VoIP applications such as IP telephony services. The application level call signaling protocols such as ITU-T H.323 and IETF SIP provide the communication functions of end-to-end call setup and release. Currently, there is a lot of H.323 based VoIP products in the market, however SIP is considered as a suitable protocol for supporting applications in IP environments, so SIP based VoIP products and services begin to appear. In this paper, firstly we present the characteristics of some possible SIP based applications and describe the design and implementation of a VoIP example service named PC-to-PC Internet telephony service using the developed SIP network components. The PC-to-PC Internet telephony service and User Agent are developed in MS window 98/2000 using visual C/C++, and Proxy server and Registrar in Linux 7.0 using C, respectively.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.39 no.7
• /
• pp.665-671
• /
• 2015

The performance of fault diagnostics for a planetary gearbox depends on vibration modulation characteristics, which can vary with manufacturing & assembly tolerance, and load condition. In this paper, a fault diagnostics technique that considers vibration modulation characteristics is proposed for the effective fault detection of planetary gearboxes in wind turbines. For identifying the vibration modulation characteristics in practice, re-sampled vibration signals are processed with narrow band-pass filters. Thereafter, the optimal position of the vibration extraction window is identified for effective detection of faulty signals under the varying vibration modulation characteristics. The proposed diagnostics technique makes it possible to perform robust diagnostics of the planetary gearbox with regard to the changeable vibration modulation effect. For demonstrating the proposed fault diagnostics technique, a 2-kW WT testbed is designed with two DC motors and gearboxes. A faulty gear with partial tooth breakage is machined and assembled into the gearbox.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.47 no.1
• /
• pp.10-18
• /
• 2010

The polar transmitter is applied to the narrowband communication systems such as GSM (Global System for Mobile Communications), EDGE (Enhanced Data Rates for GSM Evolution), and GPRS (General Packet Radio Service). To apply polar transmitter for the wideband communication like OFDM (Orthogonal Frequency Division Multiplexing) where the high PAPR (Peak-to-Average Power Ratio) problem occurs, this paper proposes a windowed-sinc function based PAPR reduction scheme. The proposed algorithm mitigates the effect of excessive suppression due to successive peaks or relatively high peaks of the signal. The BER (Bit Error Rate) and EVM (Error Vector Magnitude) performances are measured for various window types and lengths. The simulation results demonstrate that the proposed algorithm achieves significant improvement in terms of BER and PAPR reduction performance with similar spectrum performance to the conventional peak windowing scheme.

• Journal of the Korea Society of Computer and Information
• /
• v.19 no.10
• /
• pp.91-97
• /
• 2014

In this paper, we design and implement a mobile game based on windows phone platform. Visual Studio and the Windows Mobile software development kit(SDK) and developer tool kits (DTK) make it possible to create software for the Windows Mobile platform in Visual C#. Also The XNA Framework is the set of .NET libraries that developers will code against to build games. XNA Framework support PC and XBOX and a ZUNE HD multiplex platform environment and 2D and 3D games provides the necessary functions to a development. XNA Framework is to make it easier to develop games because the codes which are succeeded creates with automatic, implements a game development relation resource and the game logic. The key idea of our game is that we use shooting and ranking system to raise fun.

• Journal of the Institute of Electronics Engineers of Korea SP
• /
• v.38 no.5
• /
• pp.498-508
• /
• 2001

In this paper, we propose an efficient coding algorithm for the zoom images to find the optimal depth and texture information. The proposed algorithm is the area-based method consisting of two consecutive steps, i) the depth extraction step and ii) the texture extraction step. The X-Y plane of the object space is divided into triangular patches and the depth value of the node is determined in the first step and then the texture of the each patch is extracted in the second step. In the depth extraction step, the depth of the node is determined by applying the block-based disparity compensation method to the windowed area centered at the node. In the second step, the texture of the triangular patches is extracted from the zoom images by applying the affine transformation based disparity compensation method to the triangular patches with the depth value extracted from the first step. To improve the quality of image, the interpolation is peformed on the object space instead of the interpolation on the image plane.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.35 no.8
• /
• pp.685-692
• /
• 2007

This paper describes the development procedure of GUI Program for the automated generation of airfoil performance table used in helicopter comprehensive code. Considering commercialization, the program is developed based on the Windows operating system. In addition, it is aimed to enhance user's convenience by including embedded postprocessor which enables real-time display of calculation procedure and grid system. Using the validated CFD code, the aerodynamic analyses are automated for a given range of Mach number and angles of attack. The computational grid system is designed to generate automatically once the surface coordinates are given. Mixed-Language scheme is employed in order to combine the CFD code in Fortran with C++ based GUI program, which makes the time-consuming code conversion unnecessary.

• Journal of Broadcast Engineering
• /
• v.16 no.6
• /
• pp.902-915
• /
• 2011

Recently in the area-based stereo matching field, Adaptive Support-Weight (ASW) method that weights matching cost adaptively according to the luminance intensity and the geometric difference shows promising matching performance. However, ASW requires more computational cost than other matching algorithms do and its real-time implementation becomes impractical. By applying Integral Histogram technique after approximating to the Bilateral filter equation, the computational time of ASW can be restricted in constant time regardless of the support window size. However, Integral Histogram technique causes loss of the matching accuracy during approximation process of the original ASW equation. In this paper, we propose a novel algorithm that maintains the ASW algorithm's matching accuracy while reducing the computational costs. In the proposed algorithm, we propose Sub-Block method that groups the pixels within the support area. We also propose the method adjusting the disparity search range depending on edge information. The proposed technique reduces the calculation time efficiently while improving the matching accuracy.

• Journal of KIISE:Computer Systems and Theory
• /
• v.36 no.2
• /
• pp.60-67
• /
• 2009

Analyzing protein-protein interactions(PPI) is an important task in bioinformatics as it can help in new drugs' discovery process. However, due to vast amount of PPI data and their complexity, efficient visualization of the data is still remained as a challenging problem. We have developed efficient and effective visualization system that integrates Gene Ontology(GO) and PPI network to provide better insights to scientists. To provide efficient data visualization, we have employed dynamic interactive graph drawing methods and context-based browsing strategy. In addition, quick and flexible cross-reference system between GO and PPI; LCA(Least Common Ancestor) finding for GO; and etc are supported as special features. In terms of interface, our visualization system provides two separate graphical windows side-by-side for GO graphs and PPI network, and also provides cross-reference functions between them.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.4 no.5
• /
• pp.1095-1104
• /
• 2000

In recent years, medical procedures have become more complex, while financial pressures for shortened hospital stays and increased efficiency in patient care have increased. As a result, several shortcomings of present film-based systems for managing medical images have become apparent. Maintaining film space is labor intensive and consumes valuable space. Because only single copies of radiological examinations exist, they are prone to being lost or misplaced, thereby consuming additional valuable time and expense. In this paper, mini-PACS for image archiving, transmission, and viewing offers a solution to these problems. Proposed mini-PACS consists of mainly four parts such as web module, client-server module, internal module, acquisition module. In addition, mini-PACS system includes DICOM converter that non-DICOM file format converts standard file format. In client-server module case, proposed system is combined both SCU (service class user: client) part and SCP(service class provider: sewer)part therefore this system provides the high resolution image processing techniques based on windows platform. Because general PACS system is too expensive for medium and small hospitals to install and operate the full-PACS. Also, we constructed web module for database connection through the WWW.

• Journal of the Korea Society of Computer and Information
• /
• v.12 no.6
• /
• pp.41-48
• /
• 2007

Since the advent of object-oriented(OO) technology, research and development projects have fumed out that OO technology could importantly contribute in productivity and reusability improvement. There are various research areas related to OO technology And two of major research fields in this areas are concerned in issues for CASE tools and component-based technologies. This paper discusses a trial of applying component-based technology to a CASE tool. This paper proposes the design and implementation issues obtained while we have incrementally developed OODesigner, an OO CASE tool, with compound document support functionality based on COM/OLE technology. As OODesigner with OLE container/server functionality has interoperability with other application programs of Windows system, it can provide more powerful documentation environment than other CASE tools. OODesigner can be used not only to design UML diagrams. but also enables us to make more expressive documentation cooperatively with various kinds of OLE-enabled software like Recorder and Excel. Therefore powerful and consistent documentation activity can be achieved with the tool.