• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.367-369
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• 2002

We have designed ramp profile excitation pulse based on the Shinnar-Le Roux (SLR) algorithm. The algorithm provides many advantages to pulse designers. The first advantage is the freedom of deciding the amplitudes, frequencies, and ripple sizes of stopband, passband, and transition band of pulse profile. The second advantage is the freedom of deciding the pulse phase, more specifically, minimum phase, linear phase, maximum phase, and any phase between them. The minimum phase pulse is the best choice in the case of 3D TOF, because it minimizes the echo time, which implies the best image quality in the same MR examination condition. In addition, the half echo technique is slightly modified in our case. In general, using the half echo technique means that the acquired data size is half and the rest part can be filled with complex conjugate of acquired data. But in our case, the echo center is just shifted to left, which implies the reduction of echo time, and the acquired data size is the same as the one without using the half echo technique. In this case, the increase of right part of data leads to improvement of the resolution and the decrease of left part of data leads to decrease of signal to noise ratio. Since in the case of 3D TOF, the signal to noise ratio is sufficiently high and the resolution is more important than signal to noise ratio, the proposed method appears to be significantly affective and gives rise to the improved high resolution angiograms.

• KIISE Transactions on Computing Practices
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• v.22 no.1
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• pp.20-25
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• 2016

With the advent of the era of digital big data, the Hadoop platform has become widely used in various fields. However, the Hadoop MapReduce framework suffers from problems related to the increase of the name node's main memory and map tasks for the processing of large number of small files. In addition, a method for running C++-based tasks in the MapReduce framework is required in order to conjugate GPUs supporting hardware-based data parallelism in the MapReduce framework. Therefore, in this paper, we present a face detection system that generates a sequence file for images to process big data for images in the Hadoop platform. The system also deals with tasks for GPU-based face detection in the MapReduce framework using Hadoop Pipes. We demonstrate a performance increase of around 6.8-fold as compared to a single CPU process.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.39 no.6
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• pp.533-540
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• 2021

High-resolution satellite images have high potential to acquire geospatial information over inaccessible areas such as Antarctica. Reference data are often required to increase the positional accuracy of the satellite data but the data are not available in many inland areas in Antarctica. Therefore this paper presents a multi-image RPCs (Rational Polynomial Coefficients) sensor modeling without any ground controls or reference data. Conjugate points between multi-images are extracted and used for the multi-image sensor modeling. The experiment was carried out for Kompsat-3A and showed that the significant accuracy increase was not observed but the approach has potential to suppress the maximum errors, especially the vertical errors.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.12
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• pp.1148-1157
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• 2013

In a passive UHF RFID system, the impedance matching between tag antenna and chip as well as the protocol parameter settings in a reader plays important role in determination of the maximum read-range. Almost no paper, however, has dealt with the above issues in relation with the maximum read range. In this paper, two known methods (of using the value from data sheets and proprietary RFID tester) and our proposing method in chip impedance evaluation are compared in terms of maximum read range. The read range of tags whose antenna impedance is conjugate matched with the chip impedance obtained from the proposed method is improved maximum 73 % more than that of tags from the other methods.

• BMB Reports
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• v.42 no.11
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• pp.743-746
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• 2009

L-ascorbic acid (Vitamin C) and peptide are both useful compounds for collagen biosynthesis in cosmeceuticals (cosmetic and pharmaceutical fields). The instability of these compounds, however, limit their application in these industries. In this report, we describe the development of a novel compound, Stabilized Ascorbyl Pentapeptide (SAP), which physically is much more stable than L-ascorbic acid in water. The inhibitory effects of this SAP compound on tyrosinase and melanin synthesis is comparable to that of L-ascorbic acid. Importantly, the SAP compound displays no cytotoxicity at a high concentration (5 mM). The ability of SAP to promote collagen biosynthesis is greater than that of L-ascorbic acid or the KTTKS peptide alone. Considering the in vitro stability and functional effects, our data strongly suggest that the SAP compound is a good candidate not only as a cosmetic ingredient, but also as a wound healing agent.

• 한국전산유체공학회:학술대회논문집
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• 2004.03a
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• pp.49-55
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• 2004

This paper addresses a numerical simulation of the flow and heat transfer in a simplified model of helically coiled tube steam generator using a general purpose computational fluid dynamic analysis computer code. The steam generator model is comprised of a cylindrical shell and helically coiled tubes. A cold feed water entered the tubes is heated up, evaporates. and finally become a superheated steam with a large amount of heat transferred continuously from the hot compressed water at higher pressure flowing counter-currently through the shell side. For the calculation of tube side two-phase flow field formed by boiling, inhomogeneous two-fluid model is used. Both the internal and external turbulent flows are simulated using the standard k-e model. The conjugate heat transfer analysis method is employed to calculate the conduction in the tube wall with finite thickness and the convections in the internal and external fluids simultaneously so as to match the fluid-wall-fluid interface conditions properly. The numerical calculations are peformed for helically coiled tubes of steam generator at an integral type pressurized water reactor under normal operation. The effects of tube-side inlet flow velocity are discussed in details. The results of present numerical simulation are considered to be physically plausible based on the data and knowledge from previous experimental and numerical studies where available.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.5
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• pp.1157-1163
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• 2000

In this paper, we present a novel and practical stereo vision system that uses only one camera and four mirrors placed in front of the camera. The equivalent of a stereo pair of images are formed as left and right halves of a single CCD image by using four mirrors placed in front of the ten of a CCD camera. An object arbitrary point in 3D space is transformed into two virtual points by the four mirrors. As in the conventional stereo system, the displacement between the two conjugate image points of the two virtual points is directly related to the depth of the object point. This system has the following advantages over traditional two camera stereo that identical system parameters, easy calibration and easy acquisition of stereo data.

• Asian-Australasian Journal of Animal Sciences
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• v.6 no.2
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• pp.211-218
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• 1993

The effect of active immunization against porcine somatostatin (SRIF-14) on somatostation and somatotropin secretion profile in 18 gilts was investigated. Gilts were assigned to the following treatments: control (sham injection, n = 6); bovine serum albumin (BSA) (injection of BSA with bacterial protein adjuvant, n = 6); SRIF (injection of BSA-SRIF-14 conjugate with bacterial protein adjuvant n = 6). Serum SRIF and pST were assayed from the blood samples taken on day 7 after the last immunization injection. Anti-SRIF antibody titres were assayed in weekly samples two weeks after the initial immunization to one week after the last immunization. Results revealed that the immunization protocol used in the present investigation failed to produce antibodies capable of neutralizing endogenous somatostatin. In addition, the porcine somatotropin assay revealed no significant differences in baseline pST concentration, mean peak amplitude and number of peaks during a 24 h secretory period among SRIF, BSA and control treatment. There were also no differences in SRIF baseline concentration, peak amplitude, and number of peaks during a 24 h secretory period among any of the three treatments. Circulating concentrations of pST and pSRIF were highly correlated (r = -0.09). Furthermore, anti-SRIF antibody titre was not detected in the serum of the gilts actively immunized against SRIF. These data, collectively, suggest that the protocol employed in the present investigation for active immunization against SRIF is not an effective method for changing SRIF and pST secretion profiles of the gilt and thus to enhance performance.

• International Union of Geodesy and Geophysics Korean Journal of Geophysical Research
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• v.25 no.1
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• pp.23-34
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• 1997

Seismic tomography using the graph theoretical method of ray tracing is performed in two synthetic data sets with laterally varying velocity structures. The straight-ray tomography shows so poor results in imaging the laterally varying velocity structure that the ray-traced tomographic techniques should be used. Conventional ray tracing methods have serious drawbacks, i.e. problems of convergence and local minima, when they are applied to seismic tomography. The graph theretical method finds good approximated raypaths in rapidly varying media even in shadow zones, where shooting methods meet with convergence problems. The graph theoretical method ensures the globally minimal traveltime raypath while bending methods often cause local minima problems. Especially, the graph theoretical method is efficient in case that many sources and receivers exist, since it can find the traveltimes and corresponding raypaths to all receivers from a specific source at one time. Moreover, the algorithm of graph theoretical method is easily applicable to the ray tracing in anisotropic media, and even to the three dimensional case. Among the row-active inversion techniques, the conjugate gradient (CG) method is used because of fast convergence and high efficiency. The iterative sequence of the ray tracing by the graph theoretical method and the inversion by the CG method is an efficient and robust algorithm for seismic tomography in laterally varying velocity structures.

• YAKHAK HOEJI
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• v.59 no.4
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• pp.170-176
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• 2015

In vaccine development, the major points may be induction of effective and increased levels of antibody production. This is especially the case when the antigenic sources are carbohydrates. For many years, thus, we have researched various types of formulations such as liposomal and conjugate vaccines. However, the fastidious formulation process and high costs are a problem. For this reason, there is currently a focus on utilizing immunoadjuvants. In this present study, we tested if platycodin D (PLD) from Platycodon Radix have immunoadjuvant activity against the cell wall of Candida albicans (CACW). The resulting data showed that in the murine model of antibody production, CACW combined with PLD [CACW/PLD/IFA] increased the production of antibodies specific to C. albicans when compared to the antibody production by [CACW/IFA]-induction, which was used as a negative control (P<0.05). In the case of [CACW/PLD/IFA], the antibody production was 1.4 times as that of the CFA. In addition, formulations containing either had a prolonged antibody inducing activity maintaining the initial titers of antibody as compared to the CFA formula. Cytokine profiling with the antisera displayed that the PLD produced both Th1 and Th2 immunoresponses, but Th1 dominant was much greater (P<0.05). Furthermore, [CACW/PLD/IFA] formula enhanced resistance of mice against disseminated candidiasis, whereas the CFA had no such effect. In conclusion, PLD has an immunologic activity, which is protective against the disease. Thus, PLD can be a goof candidate for a new immunoadjuvant in development of the fungal vaccine.