• The Journal of Korean Institute of Communications and Information Sciences
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• v.16 no.2
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• pp.172-179
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• 1991

In this paper we have proposed an efficient coding algorithm using directional filtering. First an image is transformed by using DCT which has better energy compaction and then the transformed image is divided into a low frequency component and several high frequency components. The transformed coefficients of each parts are transmitted respectively by using huffman code and these are transformed inversely at receiver. For the directional components total edge images are reconstructed at zero crossing points. We are able to reduce the amount of data by getting of complex component and making directional angles 90. As a results, this proposed method is better than that of Kunt in respect of processing time and memories. We have 38dB of image quality with objective measurement of PSNR and 0.26bpp of compression ratio which is acceptable.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2007.11a
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• pp.43-57
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• 2007

This paper considers the technological competitiveness of aircraft infra industries that are bases of the aircraft industry development in Korea. We performed focus group interviews to aircraft industry specialists and classified the aircraft infra industries by eight fields: metallurgical assembly, general machinery, precision instruments, materials & parts, communication appliances, computer, semi-conductor/ electronic component, electronics. Through the United States patents analysis for the G7 countries and Korea during 1995-2006, we identified the technological specificities and competences of each country. RTA(Revealed Technology Advantage) index and CII(Current Impact Index) are used to examine the technological specificity and technological competence respectively. Finally, we introduced TCI(Technological Competitiveness Index) which could reflect quantitative level as well as qualitative level of patents for each aircraft infra industry. The results show that Korea has occupied the technological competitiveness in the semi-conductor and electronic component industry out of eight aircraft infra industries, and achieved a competitive edge in communication appliance industry in the mid 2000s.

• Journal of Power System Engineering
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• v.20 no.6
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• pp.64-70
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• 2016

The unsteady-state, incompressible and three-dimensional large-eddy simulation(LES) was carried out to evaluate the vorticity distribution of a small-size axial fan(SSAF). The X-component vorticity profiles developed around blade tips turn from axial to radial, and diminish the density of distribution according to the increase of static pressure. Otherwise, the Z-component vorticity profiles evenly develop at the region larger than the half radial distance of blade at the operating points of A and B, partly at the trailing-edge region of blade and radially over bellmouth according to the increase of static pressure.

• Proceedings of the Korea Information Processing Society Conference
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• 2010.11a
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• pp.1635-1637
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• 2010

Simulation tools help creating a low cost and efficient development of embedded system. SID is an open source simulator software that consists library of components for modelling hardware and software components. A component can be written in C/C++ and Tcl/Tk. Currently, the SID simulation toolkit only provides support for C++ and Tcl/Tk. Tcl/Tk is used to write GUI-based components. However, we have observed that Tcl/Tk components cause slow simulation response because Tcl/Tk is a script language. It is not proper for developing the cutting-edge products with rich graphics. Therefore, in this paper, we suggest Java to a new language for GUI components in SID by developing a bridge module for SID to interworking with Java components.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.7
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• pp.34-43
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• 1996

In this paper a simpel algorithm for all-digial high speed symbol synchronization is proposed. The proposed algorithm has a structure based on BECM (band-edge component maximization). The algorithm requires only tow samples per symbol for its operation. We analyze and evaluate performance of the proposed algorithm. Simulation results reveal that the proposed algorithm has better performance than the gardner algorithm in narrowband.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.11 no.4
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• pp.280-286
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• 1986

A newmethod of fast mask operators for edge detection is proposed, which is based on the matrix factorization. The output of each component in the multi-directional mask operator is obtained adding every image pixels in the mask area weighting by corresponding mask element. Therefore, it is same as the result of matrix-vector multiplication like one dimensional transform, i, e, , trasnform of an image vector surrounded by mask with a transform matrix consisted of all the elements of eack mask row by row. In this paper, for the Sobel and Prewitt operators, we find the transform matrices, add up the number of operations factoring these matrices and compare the performances of the proposed method and the standard method. As a result, the number of operations with the proposed method, for Sobel and prewitt operators, without any extra storage element, are reduced by 42.85% and 50% of the standard operations, respectively and in case of an image having 100x100 pixels, the proposed Sobel operator with 301 extra storage locations can be computed by 35.93% of the standard method.

• Journal of Digital Contents Society
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• v.8 no.3
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• pp.329-339
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• 2007

In this paper we present a facial region detection algorithm for real-time image with complex background and various illumination using spatial and temporal methods. For Detecting Human region It used summation of Edge-Difference Image between continuous image sequences. Then, Detected facial candidate region is vertically divided two objected. Non facial region is reduced using Analysis of Major Color Component. Non facial region has not available Major Color Component. And then, Background is reduced using boundary information. Finally, The Facial region is detected through horizontal, vertical projection of Images. The experiments show that the proposed algorithm can detect robustly facial region with complex background various illumination images.

• Journal of KIISE:Software and Applications
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• v.34 no.5
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• pp.447-454
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• 2007

TFT-LCD(Thin Film transistor liquid crystal display) has become actively used front panel display technology with increasing market. Intrinsically there is region of non uniformity with low contrast that to human eye is perceived as defect. As the gray level difference between the defect and the background is hardly distinguishable, conventional thresholding and edge detection techniques cannot be applied to detect the defect. Between the patterned and un-patterned LCD defects, this paper deals with un-patterned LCD defects by using independent component analysis, adaptive thresholding and skewness. Our method showed strong results even on noised LCD images and worked successfully on the manufacturing line.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.5 no.1
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• pp.65-68
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• 2004

When a monolithic component of piston and rebound is produced by sintering process, some technical problems such as clogging of holes during post-machining, dimensional change around the holes, and cracking of the component edges due to concentration of mechanical stress during machining are frequently encountered. To solve these problems, we systematically evaluated and investigated the density of green compacts and sintered parts, the microstructural change around the holes, and the attenuation and durability of the sintered parts in this study. By doing so, it was able to solve above problems.

• Journal of The Korean Astronomical Society
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• v.34 no.4
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• pp.313-315
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• 2001

Some authors have concluded that spiral structures and shocks do not develop if an adiabatic index $\gamma$ > 1.16 is adopted in accretion disc modelling, whilst others have claimed that they obtained well defined spirals and shocks adopting a $\gamma$ = 1.2 and a $M_2/ M_1$ = 1 stellar mass ratio. In our opinion, it should be possible to develop spiral structures for low compressibility gas accretion discs if the primary component is a black hole. We considered a primary black hole of 8M0 and a small secondary component of 0.5M$\bigodot$ to favour spiral structures formations and possible spiral shocks via gas compression due to a strong gravitational attraction. We performed two 3D SPH simulations and two 2D SPH simulations and characterized a low compressibility model and a high compressibility model for each couple of simulations. 2D models reveal spiral structures existence. Moreover, spiral shocks are also evident in high compressibility 2D model at the outer disc edge. We believe that we could develop even well defined spiral shocks considering a more massive primary component.