• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.11
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• pp.1686-1696
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• 2022

The impedance matching circuit design technique based on the phasor plot introduced in this paper is based on the impedance triangle of electric circuit. It is a technique that designs through the construction of a phasor figure using the values given to the matching circuit design. The design pattern is based on L-type, inverted L-type, T-type, and 𝜋-type, and unknown reactance elements are determined through phasor shapes. In this paper, using a design by phasor plot, we design several cases, such as the case where the input and output ports are pure resistance and have reactance. It was confirmed that the design value was verified by serial-parallel equivalent conversion to achieve matching. This design technique can immediately grasp the phase or size of input/output power, so it is expected to be applied mainly in a low frequency band due to rapid design change and application.

• Proceedings of the KIEE Conference
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• 1985.07a
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• pp.224-227
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• 1985

During operation of an RF glow discharge system, it can be observed that the reflected power tends to increase in small value, due to changes in the impedance of the system. This problem can be relieved by adding an automatic impedance matching circuit to the system. This paper presents a detailed method of automatically matching the input impedance of a 50 ohm transmission line to an RF glow discharge system at 13.56 MHZ.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.393-395
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• 2003

The changes of DEMs(Digital Elevation Models) will be detected to correct the information of DEMs and/or to get the information about themselves. This study suggests the evaluation of DEM using correlation coefficient value between the target and the reference DEMs for detect the changes.

• KDI Journal of Economic Policy
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• v.34 no.3
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• pp.133-186
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• 2012

This paper analyzes the effectiveness of social networks in finding jobs and estimates the value of job search network using the Korean Laber and Income Panel Study (KLIPS) dataset and utilizing the Difference-in-Difference Propensity Score Matching (PSM) methodology (Heckman et al., 1997). While the wide use of social networks in the Korean labor market is often perceived as 'nepotism,' this study confirms that social networks, by serving as an effective information transmitter between job search and recruitment, make a significant contribution to improving the adequacy of job matching in the domestic labor market. In order to verify the effectiveness of using social networks for getting jobs, this study looks into the cases of labor turnover using social networks and also not using it. In the aspect of individual satisfaction improvement relating to workplace and job duties, both cases of turnover turn out to experience an increased satisfaction by 2~3 points (on a 100-score scale). Meanwhile, as for the educational and technical adequacy improvement, no positive effects are found in the case of turnover without social networks, whereas the educational and technical adequacy improvement turns out to increase by 2.13 and 2.52 points, respectively, in the case of turnover using social networks. The effect of income increase through turnover using social networks registered 40,074 Korean won per month (as of 2010), which can be considered as the result from the improved educational and technical adequacy. Of all things being considered, the value of job search network per wage worker in the Korean society is estimated to be 18.72 million won in terms of life-cycle wage improvement, and 758.2 scores in terms of the improvement of working life satisfaction. Provided that the cash value of satisfaction score 1 is equivalent to 'n' times 10,000 won, the aggregate value of job search network is estimated to be 18.72+7.582n million won, which means the total amount of costs that a wage worker in the Korean society willingly pays to maintain and manage job networks for lifetime.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.11
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• pp.1170-1174
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• 2014

This paper suggests using the ICP (Iterative Closet Point) algorithm to compensate a two-dimensional map. ICP algorithm is a typical algorithm method using matching distance data. When building a two-dimensional map, using data through the value of a laser scanner, it occurred warping and distortion of a two-dimensional map because of the difference of distance from the value of the sensor. It uses the ICP algorithm in order to reduce any error of line. It validated the proposed method through experiment involving matching a two-dimensional map based reference data and measured the two-dimensional map.

• Journal of Institute of Control, Robotics and Systems
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• v.18 no.9
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• pp.801-805
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• 2012

This paper proposes dynamic thresholding scheme for fingerprint identification. As a user authentication method by fingerprint recognition technology, verification method based on 1:1 matching was mainly used in the past, but identification method based on 1:N matching is generally used recently. The control of the value of FAR is very important in the application areas such as access control and time attendance systems. This paper proposes dynamic thresholding scheme which could properly control the value of FAR according to the field of applications and size of the fingerprints database.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.47 no.6
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• pp.82-90
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• 2010

In this paper, A new stereo matching method based on reliability space is proposed to acquire 3D information from 2D image. In conventional stereo matching methods, speed is sacrificed to achieve high accuracy. To increase the matching speed while maintaining a high accuracy, this paper proposes this stereo matching method. It first makes the disparity space image for comparing all of the pixels on the stereo images. Then it produce reliability space through analyzing this value. and, By comparing the reliability space according to disparity, it makes disparity map. Moreover, the parts that make regional boundary errors are corrected by classifying the boundary of each region with the reference to color edge. The performance of the proposed stereo matching method is verified by various experiments. As a result, calculation cost is reduced by 30.6%, while the image quality of proposed method has similar performance with the existing method.

• Journal of Korea Multimedia Society
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• v.9 no.4
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• pp.434-442
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• 2006

This paper proposes a color-matching 3D look-up table that simplifies the complex color-matching procedure between a monitor and a mobile display device, where the image colors are processed in a device-independent color space, such as CIEXYZ or CIELAB, and gamut mapping performed to compensate the gamut difference. The transform from a device-dependent RGB color space to a device-independent color space is implemented by performing display characterization. The mobile LCD characterization error using the S-curve model is larger than the tolerance error since the mobile LCD has the channel-chromaticity-inconstancy and channel-dependence characteristics. In this paper we reduced the characterization error using the electro-optical transfer functions of X, Y, and Z value for R, G, B, C, M, Y, K components. Experimental results demonstrated that 64 ($4{\times}4{\times}4$) was the smallest size of color-matching look-up table that could produce an image with an acceptable reproduction error, based on a comparison of color-matched images resulting from the proposed color-matching look-up table and complex step-by-step color-matching procedures.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.6A
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• pp.610-617
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• 2002

In this paper, a new intermediate view reconstruction technique by using a disparity estimation method based-on the adaptive matching window size is proposed. In the proposed method, once the feature values are extracted from the input stereo image, then the matching window size for the intermediate view reconstruction is adaptively selected in accordance with the magnitude of this feature values. That is, coarse matching is performed in the region having smaller feature values while accurate matching is carried out in the region having larger feature values by comparing with the predetermined threshold value. Accordingly, this new approach is not only able to reduce the mismatching probability of the disparity vector mostly happened in the accurate disparity estimation with a small matching window size, but is also able to reduce the blocking effect occurred in the disparity estimation with a large matching window size. Some experimental results on the 'Parts' and 'Piano' images show that the proposed method improves the PSNR about 2.32∼4.16dB and reduces the execution time to about 39.34∼65.58% than those of the conventional matching methods.

• Korean Journal of Remote Sensing
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• v.21 no.6
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• pp.505-516
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• 2005

The Communications, Oceanography and Meteorology Satellite(COMS) will be launched in 2008. Ground processing for COMS includes the process of automatic image navigation. Image navigation requires landmark detection by matching COMS images against landmark chips. For automatic image navigation, a matching must be performed automatically However, if matching results contain errors, the accuracy of Image navigation deteriorates. To overcome this problem, we propose use of a robust estimation technique called Random Sample Consensus (RANSAC) to automatically detect erroneous matching. We tested GOES-9 satellite images with 30 landmark chips that were extracted from the world shoreline database. After matching, mismatch results were detected automatically by RANSAC. All mismatches were detected correctly by RANSAC with a threshold value of 2.5 pixels.