• Journal of Ginseng Research
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• v.45 no.1
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• pp.163-175
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• 2021

Background: Ginsenosides, which have strong biological activities, can be divided into polar or less-polar ginsenosides. Methods: This study evaluated the phytochemical diversity of the saponins in Panax ginseng (PG) root, American ginseng (AG) root, and Panax notoginseng (NG) root; the stem-leaves from Panax ginseng (SPG) root, American ginseng (SAG) root, and Panax notoginseng (SNG) root as well as the saponins obtained following heating and acidification [transformed Panax ginseng (TPG), transformed American ginseng (TAG), transformed Panax notoginseng (TNG), transformed stem-leaves from Panax ginseng (TSPG), transformed stem-leaves from American ginseng (TSAG), and transformed stem-leaves from Panax notoginseng (TSNG)]. The diversity was determined through the simultaneous quantification of the 16 major ginsenosides. Results: The content of ginsenosides in NG was found to be higher than those in AG and PG, and the content in SPG was greater than those in SNG and SAG. After transformation, the contents of polar ginsenosides in the raw saponins decreased, and contents of less-polar compounds increased. TNG had the highest levels of ginsenosides, which is consistent with the transformation of ginseng root. The contents of saponins in the stem-leaves were higher than those in the roots. The transformation rate of SNG was higher than those of the other samples, and the loss ratios of total ginsenosides from NG (6%) and SNG (4%) were the lowest among the tested materials. In addition to the conversion temperature, time, and pH, the crude protein content also affects the conversion to rare saponins. The proteins in Panax notoginseng allowed the highest conversion rate. Conclusion: Thus, the industrial preparation of less-polar ginsenosides from SNG is more efficient and cheaper.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.10a
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• pp.294-296
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• 2022

Atherosclerosis is a chronic vascular inflammatory disease in which plaque builds up in the arteries and impairs blood flow. This can lead to heart disease and stroke. Since most people do not have any symptoms until the artery is severely narrowed, early detection of atherosclerosis is critical. In this paper, in order to effectively detect atherosclerotic lesions in tube-shaped blood vessels, polar conversion is applied to MRI images based on the vessel center. We then propose a SE-LSTMNet model using continuous signal information for each angle of a polar coordinate image. The trained model showed classification performance of 0.9194 accuracy, 0.9370 sensitivity, 0.8796 specificity, 0.8700 F1 score, and 0.9719 AUC on the validation data.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.9
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• pp.1-8
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• 2010

A digital phase wrapping modulation (DPM) open-loop polar transmitter can be efficiently applied to a wideband orthogonal frequency division multiplexing (OFDM) communication system by converting in-phase and quadrature signals to envelope and phase signals and then employing the signal mapping process. This mapping process is very similar to quantization in a general communication system, and when taking into account the error that appears during mapping process, one can replace the coordinates rotation digital computer (CORDIC) algorithm in the coordinate conversion part with the Taylor series approximation method. In this paper, we investigate the application of the Taylor series approximation to the cartesian to polar coordinate conversion part of a DPM polar transmitter for wideband OFDM systems. The conventional approach relies on the CORDIC algorithm. To achieve efficient application, we perform computer simulation to measure mean square error (MSE) of the both approaches and find the minimum approximation order for the Taylor series approximation compatible to allowable error of the CORDIC algorithm in terms of hardware design. Furthermore, comparing the processing speeds of the both approaches in the implementation with FPGA reveals that the Taylor series approximation with lower order improves the processing speed in the coordinate conversion part.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.05a
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• pp.255-258
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• 2003

Recently, Digital Watermarking is used to authenticate data and to determine whether the data are distorted or not in medical images which is digitalized. The Fourier Mellin method using the Fourier Transform and the Log-Polar coordinate transform gets an invariant feature for RST distortion in images. But there are several problems in the real materialization. Interpolation of the image value should be considered according to the pixel position and so a watermark loss, original image distortion, numerical approximation is happened. Therefore there should be solved to realization of the Fourier Mellin method. Using the Look up table, there reduce the data loss caused by the conversion between Rectangular and Polar coordinate. After diagnose, medical images are transformed the Polar coordinate and taken the Discrete Fourier transform in the center of ROI region. Maintaining the symmetry in Fourier magnitude coefficient, the gaussian distributed random vectors and binary images are embedded in medical images.

• JSTS:Journal of Semiconductor Technology and Science
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• v.15 no.3
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• pp.427-435
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• 2015

This paper presents a high-throughput low-complexity decoder architecture and design technique to implement successive-cancellation (SC) polar decoding. A novel merged processing element with a one's complement scheme, a main frame with optimal internal word length, and optimized feedback part architecture are proposed. Generally, a polar decoder uses a two's complement scheme in merged processing elements, in which a conversion between two's complement and sign-magnitude requires an adder. However, the novel merged processing elements do not require an adder. Moreover, in order to reduce hardware complexity, optimized main frame and feedback part approaches are also presented. A (1024, 512) SC polar decoder was designed and implemented using 40-nm CMOS standard cell technology. Synthesis results show that the proposed SC polar decoder can lead to a 13% reduction in hardware complexity and a higher clock speed compared to conventional decoders.

• Ocean and Polar Research
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• v.23 no.2
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• pp.121-130
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• 2001

Geodetic datums define the size and shape of the earth and the origin and orientation of the coordinate systems used to map the earth. A lot of different datums have been developed and each nation uses its own datum as the basis for coordinate systems used to identify positions in geographic information systems. Recently GPS receivers are widely used to find out location and GPS is based on the World Geodetic System 1984(WGS-84) datum. Therefore the diversity of datums in use today requires accurate conversion between coordinates in different datums. In this study a coordinate conversion program on Windows is developed to transform between Tokyo Bessel(1941), which is the reference datum in Korea, and WGS-84. Several examples of coordinate conversion are presented and computed results are tested and proved to be correct.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.2
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• pp.379-385
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• 2004

Medical images are being managed more by PACS in general medical institutions. It is important to protect patients from being invaded their privacy related to the images. It is also necessary to confirm the ownership, the right of property of the medical images and notice whether the data are modified. In this paper, we propose a robust watermarking against RST attacks in medical images on the PACS. The proposed scheme modifies and improves Log-Polar Mapping and Fourier Mellin Transform in order to realize and recover serious image degradation and watermark data loss caused by the conversion between cartesian coordinate and log-polar coordinate. We used the radius and theta Look Up Table to solve the realization of the Fourier Mellin Transform, and inserted a watermark into 2D-DFT magnitudes using Spread Spectrum. Experimental results shows that this method are robust to rotation attack.

• Journal of Microbiology and Biotechnology
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• v.27 no.8
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• pp.1472-1482
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• 2017

Bacterial cytochrome P450 (CYP) steroid hydroxylases are effectively useful in the pharmaceutical industry for introducing hydroxyl groups to a wide range of steroids. We found a putative CYP steroid hydroxylase (BaCYP106A2) from the bacterium Bacillus sp. PAMC 23377 isolated from Kara Sea of the Arctic Ocean, showing 94% sequence similarity with BmCYP106A2 (Bacillus megaterium ATCC 13368). In this study, soluble BaCYP106A2 was overexpressed to evaluate its substrate-binding activity. The substrate affinity ($K_d$ value) to 4-androstenedione was $387{\pm}37{\mu}M$. Moreover, the crystal structure of BaCYP106A2 was determined at $2.7{\AA}$ resolution. Structural analysis suggested that the ${\alpha}8-{\alpha}9$ loop region of BaCYP106A2 is intrinsically mobile and might be important for initial ligand binding. The hydroxyl activity of BaCYP106A2 was identified using in vitro enzyme assays. Its activity was confirmed with two kinds of steroid substrates, 4-androstenedione and nandrolone, using chromatography and mass spectrometry methods. The main products were mono-hydroxylated compounds with high conversion yields. This is the second study on the structure of CYP106A steroid hydroxylases, and should contribute new insight into the interactions of bacterial CYP106A with steroid substrates, providing baseline data for studying the CYP106A steroid hydroxylase from the structural and enzymatic perspectives.

• Journal of Ginseng Research
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• v.41 no.2
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• pp.180-187
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• 2017

Background: The incidence of halitosis has a prevalence of 22-50% throughout the world and is generally caused by anaerobic oral microorganisms, such as Fusobacterium nucleatum, Clostridium perfringens, and Porphyromonas gingivalis. Previous investigations on the structure-activity relationships of ginsenosides have led to contrasting results. Particularly, the antibacterial activity of less polar ginsenosides against halitosis-related bacteria has not been reported. Methods: Crude saponins extracted from the Panax quinquefolius leaf-stem (AGS) were treated at $130^{\circ}C$ for 3 h to obtain heat-transformed saponins (HTS). Five ginsenoside-enriched fractions (HTS-1, HTS-2, HTS-3, HTS-4, and HTS-5) and less polar ginsenosides were separated by HP-20 resin absorption and HPLC, and the antimicrobial activity and mechanism were investigated. Results: HPLC with diode-array detection analysis revealed that heat treatment induced an extensive conversion of polar ginsenosides (-Rg1/Re, -Rc, -Rb2, and -Rd) to less polar compounds (-Rg2, -Rg3, -Rg6, -F4, -Rg5, and -Rk1). The antimicrobial assays showed that HTS, HTS-3, and HTS-4 were effective at inhibiting the growth of F. nucleatum, C. perfringens, and P. gingivalis. Ginsenosides-Rg5 showed the best antimicrobial activity against the three bacteria, with the lowest values of minimum inhibitory concentration and minimum bactericidal concentration. One major reason for this result is that less polar ginsenosides can more easily damage membrane integrity. Conclusion: The results indicated that the less polar ginsenoside-enriched fraction from heat transformation can be used as an antibacterial agent to control halitosis.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.39 no.2
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• pp.96-106
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• 2002

In this paper, we propose a new image-watermarking scheme lot arbitrarily shaped object based on Polar coordinates Shape Adaptive Discrete Transform (PSADT). Using log-polar coordinates conversion and shape adaptive discrete transform, the proposed watermarking method can be applied to any arbitrarily shaped image-object such as MPEG-4 VOP and is much more robust to geometrical attacks such as rotation and scaling than the conventional methods.