• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.5
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• pp.1165-1172
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• 1998

In this paper, we present a construction for binary pseudorandom sequences of period $2^{m}-1$ with ideal autocorraltion property using the polynomial $z^{d}+(z+1)^{d}$. We show that the sequence obtained from the polynomial becomes an m-sequence for certain values of d. We also find a few values of d which yield new binary sequences with ideal autocorrelation property when m is $3k{\pm}1$, where k is a positive integer. These new sequences are represented using trace function and the results are tabulated.

• Journal of Digital Convergence
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• v.14 no.1
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• pp.195-201
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• 2016

In this paper, we present the direction finding accuracy of correlative interferometer method and amplitude-phase comparison method. Spiral antennas are used for amplitude-phase comparison method and blade antennas are used for correlative interferometer method. Those are made for uniform circular array (UCA) direction finding antenna systems. We simulate the accuracy of azimuth angle with 3 antennas UCA when SNR is 20 dB and baseline is 0.5 wave length. Correlative interferometer method has better accuracy than amplitude-phase comparison method.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.12
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• pp.2693-2700
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• 2009

This paper proposes an effective compression method to utilize the 3D integral image with large amount of data obtained by a lens array in various applications. The conventional compression methods for still images exhibit low performance in terms of coding efficiency and visual quality, since they cannot remove the correlation between elemental images. In the moving picture compression methods, 1D scanning techniques that produce a sequence of elemental images are not enough to remove the directional correlation between elemental images. The proposed method effectively sequences the elemental images from an integral image by the 2D referencing technique and compresses them using the multi-frame referencing of H.264/AVC. The proposed 2D referencing technique selects the optimal reference image according to vertical, horizontal, and diagonal correlation between elemental images. Experimental results show that compression with the sequence of elemental images presents better coding efficiency than that of still image compression. Moreover, the proposed 2D referencing technique is superior to the 1D scanning methods in terms of the objective performance and visual quality.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.507-510
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• 2002

An algorithm of 3-D particle image velocimetry(3D-PIV) was developed for the measurement of 3-D velocity Held of complex flows. The measurement system consists of two or three CCD camera and one RGB image grabber. Flows size is $1500{\times}100{\times}180(mm)$, particle is Nylon12(1mm) and illuminator is Hollogen type lamp(100w). The stereo photogrammetry is adopted for the three dimensional geometrical mesurement of tracer particle. For the stereo-pair matching, the camera parameters should be decide in advance by a camera calibration. Camera parameter calculation equation is collinearity equation. In order to calculate the particle 3-D position based on the stereo photograrnrnetry, the eleven parameters of each camera should be obtained by the calibration of the camera. Epipolar line is used for stereo pair matching. The 3-D position of particle is calculated from the three camera parameters, centers of projection of the three cameras, and photographic coordinates of a particle, which is based on the collinear condition. To find velocity vector used 3-D position data of the first frame and the second frame. To extract error vector applied continuity equation. This study developed of various 3D-PIV animation technique.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.6
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• pp.891-897
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• 2013

The spectrum and the number of the values of the cross-correlation function between the maximal period binary sequences have been extensively studied because of their importance in communications applications. In this paper, we propose the new family of the sequences using the decimation $d=2^{m-1}(3{\cdot}2^{m}-1)$. And we find the spectrum of the cross-correlation function of the sequences and analyze the number of times each value occurs for $0{\leq}{\tau}{\leq}2^{n}-2$.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.1574-1579
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• 2004

A simultaneous measurement system that can analyze the flow-structure interactions(FSI) has been constructed and analyses on the flow field and the motion field of a floating cylinder was made. The three-dimensional vector fields around the cylinder are measured by 3D-PTV technique while the motion of the cylinder forced by the flow field is measured simultaneously with a newly developed motion tracking algorithm(bidirectional tracking algorithm). The cylinder is pendant in the working fluid of a water channel and the surface of the working fluid is forced sinusoidal to make the cylinder bounced. The interaction between the flow fields and the cylinder motion is examined quantitatively.

• Korean Journal of Environmental Agriculture
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• v.13 no.2
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• pp.151-159
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• 1994

This study was conducted to investigate the $NO_3-N$ concentration, the relationship between $NO_3-N$ and other ions, and patterns of ions in ground water used as drinking water in Cheju Island. Samples were collected from 19 wells in the northwest region, near the district of poultry complex, and 9 wells in the northeast region. In the northwest region, $NO_3-N$ concentrations in D-14 and D-202 wells near the pig farming facilities were 10.95 and 13.1 mg/L, respectively, exceeding the standard concentration of drinking water. The concentration in D-65, D-35, and D-120 wells were slightly lower than the standard concentration. However, $NO_3-N$ concentrations in the wells in the northeast region were lower than 3mg/L. In wells in the northwest region, $NO_3-N$ concentrations were negatively correlated with pH and positively correlated with $Ca^{++}$, $Mg^{++}$, $Na^+$ $Cl^-$, $SO_4^{--}$, and $Cl^-/HCO_3^-$. However, in the northeast region, they were not related with pH and the ions. The chemical compositions in D-65, D-35, and D-41 wells showed higher concentrations of $Ca^{++}$, $Mg^{++}$, $Na^+$, $Cl^-$, $NO_3-N$ and $SO_4^{--}$ than the unpolluted D-42 well. These results suggest that ground water near the pig farming complex was polluted by pig farming waste in the northwest region.

• Journal of Nutrition and Health
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• v.47 no.5
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• pp.321-329
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• 2014

Purpose: The aim of this study was to determine the relationship between serum concentrations of 25-hydroxyvitamin D [25(OH)D] and chronic obstructive pulmonary disease (COPD) prevalence. Methods: The analysis was performed using data from the Fifth Korean National Health and Nutrition Examination Survey, a cross-sectional survey of the Korean civilian population conducted from 2010 to 2012. The analyses were restricted to males who were 40 years of age and above. Complex sample multiple logistic regression analyses were used to examine the associations of COPD prevalence with 25(OH)D and other factors. Results: $FEV_1/FEV_6$ varied significantly with smoking status, age, household income, education level, occupation, body mass index (BMI), and physical activity (p < 0.05). In univariate analysis, smoking status, BMI, household income, education level, and occupation showed association with COPD (p < 0.05), but vitamin D was not associated with COPD (p = 0.078). However, when adjusted with smoking status, household income, education level, occupation, BMI, age, and smoking index, the lowest quartile of 25(OH)D showed OR 1.643 (95% CI 1.161-2.236) compared to 3rd quartile (p = 0.024). Conclusion: A significant relationship was observed between serum concentration of 25(OH)D and COPD.

• Journal of the HCI Society of Korea
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• v.7 no.1
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• pp.1-10
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• 2012

This paper deals with the effects of seat position in the theater on viewers' visual fatigue, presence, and perceived characteristics. As a result of this study, there is a significantly positive effect of Dx(deviation from mean distance from the screen) and viewing angle on visual fatigue. Second, there is no significant effect of seat position on presence. Finally, there is a significantly negative effect of Dx and viewing angle on perceived characteristics. This means, as the author assume, the seat position in the theater during watching a 3D movie is important in case of visual fatigue and perceived characteristics. This paper provides an empirical result related to effect of spatial variable at 3D theater on 3D effect. The results could be helpful to establish spatial standard in 3D theater and 3D contents; furthermore, it could help to establish regulations of visual fatigue induced from 3D effects and indications for 3D efficiency.

• Journal of the Korean Chemical Society
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• v.48 no.3
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• pp.261-265
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• 2004

We investigated the order of local movement of functional groups (-C(=O)O) in a liquid crystalline (LC) oligomer (12-4) using 2D Raman correlation spectroscopy. The results suggest that the free carbonyl near the ethyl terminal group moved first, followed by the hydrogen-bonded group. The free carbonyl group between the biphenyl groups rarely moved. Interestingly, 2D sample-to-sample correlation spectroscopy (2D STSCS) revealed that some of the carbonyl modes started to move at far below (50$^{\circ}C$) the LC temperature (135$^{\circ}C$), countering conventional beliefs.