• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.7
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• pp.65-75
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• 1996

The probability distributio function (pdf) of transmitted symbols should be asymmectric for recovering the received data in the 3rd order blind equalizer system. In this paper, we hav edesigned the blind equalizer using symmetric-asymmetric (SA) and asymmetric-symmetric (AS) transforms for less computational complexities and robustness in the noisy environments. The method of SA and AS transform was peformed using natural logarithmic operation. This paper proves that the proposed in this paper can be performed as real time operation. This paper proves that the compression factor k has no effet on transmitted symbols. Also 3rd order equalization method proposed in this paper can be performed as real time operation. As a result of computer simulatio, the computational complexity of proposed algorithm is reduced to be an half of 4th order method and MSE is enhanced as 10dB at the case of 4-PAM and 15dB at the case of 8-PAM respectivley. Conclusively, we have found that 3rd order blind equalizer can be implemented when the pdf of transmitter is asymmetric.

• Proceedings of the Acoustical Society of Korea Conference
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• 1985.10a
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• pp.68-71
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• 1985

In this paper, Sentence-Sip E Il Ka Gi Seo U1 E Gan Da was spoken by 4 men and 3 see sound is used for the experiment. A/D conversion time is 30 sec. Data are obtained using the microcomputer and compressed by ADPCM Rate of compression is 1/8. Data compressed by ADPCM are synthesized and compared to the original sound. Rate of speech identification is analysed using the sound pressure, white noise. Coding of ADPCM is done for 5bit. As the result of fixing starting voltage by 2.6V. It is acertained that variable value increases in initial speech signal and then process is made by minimum value "3". From the result of processing, synthesized sound is almost eaual to original sound. Minimum values cause distorition, Dummy Head System is used in this experiment.xperiment.

• Transactions of Materials Processing
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• v.12 no.2
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• pp.110-115
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• 2003

This paper is concerned with the compression test and forming process of flange by using virtual reality and analysis(simulation) program. This virtual manufacturing can be carried out one personal computer without any expensive devices for experiment. The virtual manufacturing composed of three modules such as the imput, calculation and the output modules on internet. Internet user can give the material's property and process parameters to the sever computer at the input module. On the calculation module, a simulator computes the virtual manufacturing process by analysis program and stores the data as a file. The output module is the program in which internet user can confirm virtual manufacturing results by showing tables, graphs, and 3D animation. This programs is designed by an internet language such as HTML, CGI, VRML and JAVA ,while analysis programs use the finite increasing, the virtual manufacturing technique will substitute many real experiments in the future.

• 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.

• Journal of information and communication convergence engineering
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• v.12 no.1
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• pp.53-59
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• 2014

Motion estimation is a core part of most video compression systems since it directly affects the output video quality and the encoding time. The full search (FS) technique gives the highest visual quality but has the problem of a significant computational load. To solve this problem, we present in this paper a modified median (MMED) operation and advanced search strategies for fast motion estimation. The proposed MMED operation includes a temporally co-located motion vector (MV) to select an appropriate initial candidate. Moreover, we introduce a search procedure that reduces the number of thresholds and simplifies the early termination conditions for the determination of a final MV. The experimental results show that the proposed approach achieves substantial speedup compared with the conventional methods including the motion vector field adaptive search technique (MVFAST) and predictive MVFAST (PMVFAST). The proposed algorithm also improves the PSNR values by increasing the correlation between the MVs, compared with the FS method.

• Journal of information and communication convergence engineering
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• v.6 no.1
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• pp.29-33
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• 2008

This paper presents the proposal and hardware design of JPEG baseline encoder. The JPEG encoder system consists of line buffer, 2-D DCT, quantization, entropy encoding, and packer. A fully pipelined scheme for JPEG encoder is adopted to speed-up an image compression. The proposed architecture was described in VHDL and synthesized in Xilinx ISE 7.1i and simulated by modelsim 6.1i. The results showed that the performance of the designed JPEG baseline encoder is higher than that demanded by real-time applications for $1024{\times}768$ image size. The designed JPEG encoder IP can be easily integrated into various application systems, such as scanner, PC camera, color FAX, and network camera, etc.

• Food Science and Biotechnology
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• v.16 no.2
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• pp.234-237
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• 2007

Water resistance of three biopolyester films, such as poly-L-lactate (PLA), poly-hydroxybutyrate-co-valerate (PHBV), and Ecoflex, and low density polyethylene (LDPE) film was investigated by measuring contact angle of various probe liquids on the films. The properties measured were initial contact angle of water, dynamic change of the water contact angle with time, and the critical surface energy of the films. Water contact angle of the biopolyester films ($57.62-68.76^{\circ}$) was lower than that of LDPE film ($85.19^{\circ}$) indicating biopolyester films are less hydrophobic. The result of dynamic change of water contact angle also showed that the biopolyester films are less water resistant than LDPE film, but much more water resistant than cellulose-based packaging materials. Apparent critical surface energy for the biopolyester films (35.15-38.55 mN/m) was higher than that of LDPE film (28.59 mN/m) indicating LDPE film is more hydrophobic.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2001.04a
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• pp.207-214
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• 2001

In Korea, the multi-dwelling residential buildings are most popular housing system that is reinforced concrete shear wall system. However, the serviceability and safety of the system have been decreased because of the errors in design or construction and inadequate maintenance. In addition the safety of the system cannot be evaluated reasonably because the system is analyzed by the deterministic approach. Therefore, this study is aimed to analyze reinforced concrete shear walls by the reliability approach considering uncertainty based on the probability theory. In this study, a reliability analysis program using MATLAB is developed by combining AFOSM and Sampling Method for the reinforced concrete shear walls within feasible design area. The reasonable reliability index β of ultimate limit states for RC shear walls are calculated automatically using this developed program with the measured data those have means and standard deviations in the field. The ultimate states are compression failure, tension failure, governing compression, and governing bending of the reinforced concrete shear walls respectively. To estimate the safety of the system using developed program can be used to predict residual life-time of the system.

• The Transactions of the Korea Information Processing Society
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• v.5 no.4
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• pp.1057-1065
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• 1998

This paper describes a new fractal image coding algorithm to shorten time to take on fractal image encoding by using limited search area method and scaling method. First, the original image is contracted respectively by half and by quarter with the scaling method. And then, the corresponding domain block of the quarter-sized image which is most similar with one range block of the half-sized image is searched within the limited area in order to reduce the encoding time extremely. This searched block is used in encoding. Also, we propose an algorithm provided much shorter encoding time and better compression ratio with a little degradation of the decoded image quality than Jacquin's method.

• IEMEK Journal of Embedded Systems and Applications
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• v.18 no.2
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• pp.51-58
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• 2023

This paper proposes a deep learning method for estimating the heart rate from facial videos. Our proposed method estimates remote photoplethysmography (rPPG) signals to predict the heart rate. Although there have been proposed several methods for estimating rPPG signals, most previous methods can not be utilized in low-power single board computers due to their computational complexity. To address this problem, we construct a lightweight student model and employ a knowledge distillation technique to reduce the performance degradation of a deeper network model. The teacher model consists of 795k parameters, whereas the student model only contains 24k parameters, and therefore, the inference time was reduced with the factor of 10. By distilling the knowledge of the intermediate feature maps of the teacher model, we improved the accuracy of the student model for estimating the heart rate. Experiments were conducted on the UBFC-rPPG dataset to demonstrate the effectiveness of the proposed method. Moreover, we collected our own dataset to verify the accuracy and processing time of the proposed method on a real-world dataset. Experimental results on a NVIDIA Jetson Nano board demonstrate that our proposed method can infer the heart rate in real time with the mean absolute error of 2.5183 bpm.