• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.1
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• pp.67-74
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• 2022

To analyze the motion of aircraft through computing the dynamics equations, true airspeed is essential for obtaining aerodynamic loads. Although the airspeed is measured by on-board instruments such as pitot tubes, measurement data are difficult to obtain for commercial flights because they include sensitive data about the airline operations. One of the commonly available trajectory data, Automatic Dependent Surveillance-Broadcast data, provide aircraft's speed in the form of ground speed. The ground speed is a vector sum of the local wind velocity and the true airspeed. This paper present a method to estimate true airspeed by combining the trajectory, meteorological, and topology data available to the public. To integrate each data, we first matched the coordinate system and then unified the altitude reference to the mean sea level. We calculated the wind vector for all trajectory points by interpolating from the lower resolution grid of the meteorological data. Finally, we calculate the true airspeed from the ground speed and the wind vector. These processes were applied to several sample trajectories with corresponding meteorological data and the topology data, and the estimated true airspeeds are presented.

• Journal of the Korean Society for Marine Environment & Energy
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• v.8 no.3
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• pp.116-121
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• 2005

In the present paper, a new calculation algorithm far solving large scale environmental or geophysical flows with free surface is proposed where the non-hydrostatic pressure component is taken into consideration. Predictor-corrector fractional step approach with explicit, forward time marching scheme in the sigma coordinate system is employed. In order to validate the present calculation algorithm and to estimate the effects of non-hydrostatic pressure on resultant flow and free surface movements, example calculations are carried out for typical steady and unsteady flow problems. Present method can be applied to the meso-scale free surface flows with complex bottom topography where MAC-like 3-d hydrodynamic calculations are quite ineffective and uneconomic.

• Explosives and Blasting
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• v.9 no.1
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• pp.3-13
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• 1991

The cautious blasting works had been used with emulsion explosion electric M/S delay caps. Drill depth was from 3m to 6m with Crawler Drill ${\phi}70mm$ on the calcalious sand stone (soft -modelate -semi hard Rock). The total numbers of test blast were 88. Scale distance were induced 15.52-60.32. It was applied to propagation Law in blasting vibration as follows. Propagtion Law in Blasting Vibration $V=K(\frac{D}{W^b})^n$ were V : Peak partical velocity(cm/sec) D : Distance between explosion and recording sites(m) W : Maximum charge per delay-period of eight milliseconds or more (kg) K : Ground transmission constant, empirically determind on the Rocks, Explosive and drilling pattern ets. b : Charge exponents n : Reduced exponents where the quantity $\frac{D}{W^b}$ is known as the scale distance. Above equation is worked by the U.S Bureau of Mines to determine peak particle velocity. The propagation Law can be catagorized in three groups. Cubic root Scaling charge per delay Square root Scaling of charge per delay Site-specific Scaling of charge Per delay Plots of peak particle velocity versus distoance were made on log-log coordinates. The data are grouped by test and P.P.V. The linear grouping of the data permits their representation by an equation of the form ; $V=K(\frac{D}{W^{\frac{1}{3}})^{-n}$ The value of K(41 or 124) and n(1.41 or 1.66) were determined for each set of data by the method of least squores. Statistical tests showed that a common slope, n, could be used for all data of a given components. Charge and reduction exponents carried out by multiple regressional analysis. It's divided into under loom over loom distance because the frequency is verified by the distance from blast site. Empirical equation of cautious blasting vibration is as follows. Over 30m ------- under l00m ${\cdots\cdots\cdots}{\;}41(D/sqrt[2]{W})^{-1.41}{\;}{\cdots\cdots\cdots\cdots\cdots}{\;}A$ Over 100m ${\cdots\cdots\cdots\cdots\cdots}{\;}121(D/sqrt[3]{W})^{-1.66}{\;}{\cdots\cdots\cdots\cdots\cdots}{\;}B$ where ; V is peak particle velocity In cm / sec D is distance in m and W, maximLlm charge weight per day in kg K value on the above equation has to be more specified for further understaring about the effect of explosives, Rock strength. And Drilling pattern on the vibration levels, it is necessary to carry out more tests.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.11C
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• pp.1040-1048
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• 2009

This paper proposes an auto flesh tone balance algorithm for the picture that is taken for people. General white balance algorithms bring neutral region into focus. But, other objects can be basis if its spectral reflectance is known. In this paper the basis for white balance is human face. For experiment, first, transfer characteristic of image sensor is analyzed and camera output RGB on average face chromaticity under standard illumination is calculated. Second, Output rate for the image is adjusted to make RGB rate for the face photo area taken under unknown illumination RGB rate that is already calculated. Input tri-stimulus XYZ can be calculated from camera output RGB by camera transfer matrix. And input tri-stimulus XYZ is transformed to standard color space (sRGB) using sRGB transfer matrix. For display, RGB data is encoded as eight-bit data after gamma correction. Algorithm is applied to average face color that is light skin color of Macbeth color chart and average color of various face colors that are actually measured.

• Progress in Medical Physics
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• v.13 no.1
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• pp.9-14
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• 2002

We invented the newly developed Fractionated Stereotactic Radiotherapy(F.S.R.T) system using combined techniques of couch mounting and pedestal mounting system. Head fixation frame consists of a milled alluminium alloy(duralumin) and is placed to the couch. This frame immobilized patient head using the dental bite, 3.2 mm frontal and occipital thermoplastic mask. To evaluate the coordinate of target isocenter, Brown-Revert-Walls C.T localizer can be attached to this frame. And also, we developed the frame mounting system by developing the modification of pedestal mounting system. This system is fixed to couch floor and can be used to evaluate the isocenteric accuracy of gantry, couch and collimator in Q.A procedure. In order to measure the relocation accuracy, the acrylic phantom and the accurate pointers have been made. The repositioning of the targets in the phantom were estimated by comparing C.T coordinates and E.C.L portal films taken with anterior-posterior and right-left direction. From the results of experiments, the average distance errors between the target isocenter and its mean position were 0.71$\pm$0.19 for lateral, 0.45$\pm$0.15 for inferior-superior, 0.63$\pm$0.18 for anterior-posterior. And the maximum distance error was less than 1.3 mm. The new head fixation frame and frame mounting system were non-invasive, accurately relocatable, easy to use, very light and well tolerable by the results of phantom tests. The major advantage of using this frame mounting system is complete access to any point in the Patients cranium especially posterior direction

• The KIPS Transactions:PartB
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• v.14B no.5
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• pp.329-336
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• 2007

In this paper we propose both the construction of image DB including information on the shooting location and direction of the captured outdoor images and the efficient retrieval method from the DB. Furthermore, for the automatic extraction of the location and direction information, we suggest to have the Digital Camera equipped with an expandable GPS modulo which has a function to calculate the location and direction and also to utilize GPS IFD tags in the EXIF. Then that will make it possible for us to retrieve quickly and precisely the target image with its geography and other objects on the ground included. In the previous retrieval method based only on the location, we eel some extra useless images due to the fact that all the images in the ROI(Region Of Interest) are searched on one condition, radius. However, with the proposed method in this paper, we can not only retrieve all the images selectively within the ROI but also achieve nearly 100% of precision when we search for the target images within DOI(Direction Of Interest) with another condition, direction, added. Applying this method to an image retrieval system, we can classify or retrieve natural images based on the location and direction information, which, in turn, will be vitally useful to diverse industrial fields such as disaster alarm system, fire and disaster prevention system, traffic information system, and so forth.

• Journal of the Korean Chemical Society
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• v.20 no.1
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• pp.3-14
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• 1976

The crystal structure of alicylaldehyde-4-piperidinothiosemicarbazone, $C_{13}H_{l7}N_3OS$, has been determined by single crystal X-ray analysis. The crystals are orthorhombic, space group $P2_12_12_1$, with unit cell dimensions a = 6.52(2), b = 13.42(4), c = 14.92(4)${\AA}$. There are four formular units in a unit cell. The structure was solved by the heavy atom method and refined by isotropic block diagonal least-squares methods to a final R value of 0.10 for 1019 observed reflections. The oxygen atom of the hydroxyl group is involved in two hydrogen bonds, one as donor in the intramolecular O-H${\cdots}$N hydrogen bond and the other as acceptor in the intermolecular N-H${\cdots}$O hydrogen bond, the distances of the hydrogen bonds 2.56 and 3.00${\AA}$ respectively.The molecules are joined into infinite columns by the N-H${\cdots}o$O hydrogen bonds which form spirals along the two fold screw axis parallel to the a axis. The molecular columns are held together by van der Waals forces.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.10a
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• pp.190-192
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• 2018

This paper describes a design of an elliptic curve cryptography (ECC) processor that supports five pseudo-random curves and five Koblitz curves over binary field defined by the NIST standard. The ECC processor adopts the Lopez-Dahab projective coordinate system so that scalar multiplication is computed with modular multiplier and XORs. A word-based Montgomery multiplier of $32-b{\times}32-b$ was designed to implement ECCs of various key lengths using fixed-size hardware. The hardware operation of the ECC processor was verified by FPGA implementation. The ECC processor synthesized using a 0.18-um CMOS cell library occupies 10,674 gate equivalents (GEs) and 9 Kbits RAM at 100 MHz, and the estimated maximum clock frequency is 154 MHz.

• Applied Chemistry for Engineering
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• v.33 no.3
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• pp.279-283
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• 2022

UV-vis spectroscopy is one of the powerful tools for measuring the concentrations of reactant and products during a chemical reaction. However, there is an limitation of using the technique when the reaction undergoes in high concentration and high temperature. Color analysis using camera images can provide the identical results with UV-vis analysis with regardless of the sample concentration and temperature. The catalytic reduction reaction of resazurin to resorufin was investigated using the color analysis with the color spaces such as CIE L^*a^*b^*. Moreover, the color analysis enabled the independent analysis of two different material's concentrations without the deconvolution of overlapped wavelengths unlike the case of using UV-vis spectroscopy.

• Progress in Medical Physics
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• v.20 no.1
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• pp.1-6
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• 2009

For HDR intracavitary brachytherapy with ovoids and a tandem, we compared the dose discrepancy of treatment plans using two different Ir-192 sources (microSelectron, Varian) and generated on two different treatment planning systems (PLATO, BrachyVision). The treatment plans of ten patient treated from Oct. 2007 to Jan. 2008 were selected for these comparisons. For the comparison of dose calculation using different sources, the average discrepancies were $-0.91{\pm}0.09%$, $-0.27{\pm}0.07%$, $0.22{\pm}0.39%$, and $0.88{\pm}0.37%$ in total treatment time and at B-point and ICRU bladder and rectum reference point, respectively. Comparing the two systems, the average dose discrepancies between treatment planning programs were $-0.22{\pm}0.42%$, $-0.25{\pm}0.29%$, $-0.23{\pm}0.63%$, and $-0.17{\pm}0.76%$, and the average dose discrepancies between positioning methods (PLATO with film and BrachyVision with digitial image) were $-0.61{\pm}0.59%$, $-0.77{\pm}0.45%$, $-0.72{\pm}1.70%$, and $0.35{\pm}2.82%$ at A-point, B-point, and ICRU bladder and rectum reference points, respectively. The rectal dose discrepancies between two systems were reached 5.87%. The difference in the dwell position expected by each TPS are mainly affected by the differences in the positioning method in TPSs and have an effect on dose calculations of rectal and bladder located in AP direction.