• Journal of Internet Computing and Services
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• v.6 no.6
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• pp.149-161
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• 2005

Catadioptric mirrors are widely used in automatic surveillance system. The major drawback of catadioptric mirror is its unequal image resolution. Equidistance catadioptric mirror can be the solution to this problem. Even double panoramic structure can generate stereo images with single camera system. So two images obtained from double panoramic equidistance catadioptric mirror can be used in finding the depth and height values of object's points. But compared to the single catadioptric mirror. the image size of double panoramic system is relatively small. This leads to the severe accuracy problem in estimation. The exact axial alignment and the exact mount of mirror are the sources that can be avoided but the focal length variation is inevitable. In this paper, the effects of focal length variation on the computation of depth and height of object' point are explained and the effective focal length finding algorithm, using the assumption that the object's viewing angles are almost same in stereo images, is presented.

• Korean Journal of Optics and Photonics
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• v.24 no.1
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• pp.29-38
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• 2013

In this paper, the illumination performances of three freeform lenses optimally designed for a point source were investigated for several LEDs with different source sizes, and also the tolerance characteristics of the lenses were analyzed. For comparison, two lenses with different sizes were designed with a divergent illumination model, and the last one was done with an overlapped illumination model. As the LED source size increased, the illuminance uniformity decreased more strongly, and the influence of a source misalignment on illumination performance became insignificant. However, the variation of LED radiation characteristics had strong effect on the illumination performance, irrespective of LED source size. Even though the lens based on a divergent illumination model showed superior performance compared to the lens based on an overlapped illumination model, the latter was less sensitive to the variation of LED radiation characteristics.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.9 no.2
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• pp.148-154
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• 2016

In recent year, the interests of PQ is increase due to the increasing of non-linear load and distributed power sources in power system. For the parameters detection and feature extraction of PQ, and the PQ improvement method, continuous power signal monitering is needed. In this paper, the power signal compression and reconstruction method is suggested for power signal monitering. The power signal is compressed using DCT that has good compression performance, and the compressed signal is reconstructed through IDCT. And for the higher compression rate, DCT coefficients are arranged by magnitude in compression process, and in recouction process DCT coefficients are rearranged to original frequency position. The synthesized signal according to the IEC standard is used used in compression and reconstruction simulations. The performances of the proposed method are verified by comparing the error between synthesized signal and reconstructed signal.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.42 no.1
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• pp.1-7
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• 2005

We propose an effective Landsat TM image compression method using the classified bidirectional prediction (CBP), the classified KLT and the SPIHT. The SPIHT is used to exploit the spatial redundancy of feature bands selected in the visible range and the infrared range separately. Regions of the prediction bands are classified into three classes in the wavelet domain, and then the CBP is performed to exploit the spectral redundancy. Residual bands that consist of difference values between the original band and the predicted band are decorrelated by the spectral KLT Finally, the three dimensional (3-D) SPIHT is used to encode the decorrelated coefficients. Experiment results show that the proposed method reconstructs higher quality Landsat TM image than conventional methods at the same bit rate.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.12
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• pp.1207-1212
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• 2015

A vibro ripper utilizes high-frequency vibration for rock fragmentation. This concept is different from those used by other existing breakers. The gearbox-shank welded joint of a vibro ripper is a very important part. Because it delivers the vibromotive force to the tooth, it is important to predict its soundness. This study was conducted to predict the fatigue life under welding conditions. The shank materials were Hardox-Hituf and AR400, and the filler metals were CSF-71T and CSF-81T. Fatigue tests were conducted under each set of conditions. P-S-N curves are presented based on the statistical testing method recommended by JSME-S002, and a comparison is made of the results under each set of conditions. The life was estimated using a P-S-N curve.

• Aerospace Engineering and Technology
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• v.6 no.1
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• pp.146-156
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• 2007

In this paper, the TVC actuation test and analysis results for a flexible seal kick motor nozzle are presented. A real-sized test model of KSLV-I kick motor system is applied to water pressurizing TVC tests which investigate the property changes in TVC nozzle expansion and TVC actuation performance against chamber pressure changes. The equipments which are required for TVC actuation tests are briefly explained. The TVC actuation tests are firstly accomplished in static mode, which reveals TVC error characteristics including thrust misalignment, control accuracy, and TVC stroke increase, etc. The properties in frequency domain is given via dynamic tests. These results may play an important role in enhancing the TVC control performance of KSLV-I.

• The Journal of Engineering Geology
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• v.29 no.4
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• pp.469-481
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• 2019

In addition to structural stabilization measures such as the construction of Sand Dam, non-structural management measures such as reasonable water demand and supply volume management are needed to prevent limited water supply damage due to drought. In this study, water supply-demand monitoring system was established for drought response in Seosang-ri basin in Chuncheon, the main source of domestic water for small water facilities. The flow rate of the stream was measured for monitoring the supply volume, and the daily flow rate was calculated by using it to calibrate the parameters of the SWAT (Soil and Water Assessment Tool). To monitor demand, the daily usage was calculated by measuring the change in the water level of the water tank. The relationship between the finally calculated daily supply and demand amount was analyzed to identify the shortage of water.

• Korean Journal of Food Science and Technology
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• v.29 no.2
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• pp.249-254
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• 1997

Stevioside was transglucosylated to improve its sweetness. Eighteen conditions were tested using the tables of orthogonal arrays of $L_{18}\;(2^{1}{\times}3^{7})$. Statistical analysis showed that the transglucosylation rate was significantly affected by temperature, the ratio of co-substrate (maltodextrin) to stevioside, pH, DE of maltodextrin and concentration of stevioside, in their order. Optimum conditions selected for temperature, ratio of co-substrate to stevioside, pH and DE of maltodextrin were $80^{\circ}C$, 1.0, 6.0 and 15, respectively. Glycosyl-stevioside with 68% yield of transglucosylation was produced at the optimum condition and found to have better quality in sweetness than stevioside and rebaudioside A.

• Bioinformatics and Biosystems
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• v.1 no.1
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• pp.82-87
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• 2006

The most popular protein structure prediction method is comparative modeling. To guarantee accurate comparative modeling, the sequence alignment between a query protein and a template should be accurate. Although choosing the best template based on the protein sequence alignments is most critical to perform more accurate fold-recognition in comparative modeling, even more critical is the sequence alignment quality. Contrast to a lot of attention to developing a method for choosing the best template, prediction of alignment accuracy has not gained much interest. Here, we develop a method for prediction of the shift score, a recently proposed measure for alignment quality. We apply support vector regression (SVR) to predict shift score. The alignment between a query protein and a template protein of length n in our own library is transformed into an input vector of length n +2. Structural alignments are assumed to be the best alignment, and SVR is trained to predict the shift score between structural alignment and profile-profile alignment of a query protein to a template protein. The performance is assessed by Pearson correlation coefficient. The trained SVR predicts shift score with the correlation between observed and predicted shift score of 0.80.

• Journal of the Korean Society for Nondestructive Testing
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• v.32 no.2
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• pp.177-184
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• 2012

An optical defect detection method using ESPI(electronic speckle pattern interferometry) is proposed. ESPI is widely used as a non-contact measurement system which show deformation and phase map in real time. ESPI can be divided as the in-plane, out-of-plane and shearography by operation principle and target object and also divided with bulk type and optic fiber type by the optic configurations. This paper is focused on optic fiber type out-of-plane ESPI, which has the following advantages: (1) low cost; (2) reduction of the unreliable factors generated by separated optic components; (3) simplification of the optic configuration; (4) great reduction of volume; (5) flexibility, to be easily designed into different structures to adapt to inaccessible environments such as pipeline cavity and so on.