• Journal of the Korean Institute of Telematics and Electronics A
• /
• v.31A no.6
• /
• pp.1-8
• /
• 1994

In this paper, in order to apply the idea MDPSK to TCM, we use signal set expansion and set partition by phase differences. Through this we propose the trellis-coded MDPSK. And the Viterbi decoder containing branch metrics of the squared Euclidean distance of the Lth order phase difference as well as the first order phase difference is introduced in order to improve the bit error rate(BER) in the differential detection of the trellis-coded MDPSK. The proposed Viterbi decoder is conceptually same to the sliding multiple symbol dection method which uses the branch metric with the first and Lth order phase differences. We investigate the performance of the uncoded DQPSK and the trallis-coded D8PSK in additive white Gaussian noise (AWGN) through the Monte Carlo simulation under the two cases of using and not using the Lth order phase difference metric. The study shows that trellis-coded 8DPSK is an attractive scheme for power and bandlimited systems while also improving the BER performance when the Viterbi decoder is employed to the Lth order phase order difference metric. This performance improvement has been obtained without sacrificing the bandwidth or the power efficiency.

• Bulletin of the Korean Chemical Society
• /
• v.25 no.2
• /
• pp.271-279
• /
• 2004

The aroma component of Hallabong peel has been characterized by GC-MS with two different extraction techniques: solid-phase trapping solvent extraction (SPTE) and headspace solid-phase microextraction (HSSPME). Aroma components emitted from Hallabong peel were compared with those of other citrus varieties: lemon, orange and grapefruit by SPTE and GC-MS. d-Limonene (96.98%) in Hallabong was the main component, and relatively higher peaks of cis- ${\beta}$-ocimene, valencene and -farnesene were observed. Other volatile aromas, such as sabinene, isothujol and ${\delta}$-elemene were observed as small peaks. Also, principal components analysis was employed to distinguish citrus aromas based on their chromatographic data. For HSSPME, the fiber efficiency was evaluated by comparing the partition coefficient ($K_{gs}$Kgs) between the HS gaseous phase and HS-SPME fiber coating, and the relative concentration factors (CF) of the five characteristic compounds of the four citrus varieties. 50/30 ${\mu}$m DVB/CAR/PDMS fiber was verified as the best choice among the four fibers evaluated for all the samples.

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
• /
• 2001.06a
• /
• pp.1131-1131
• /
• 2001

To develop a nondestructive quality evaluation technique of fruits, a K-mean algorism is applied to near infrared (NIR) spectroscopy of apples. The K-mean algorism is one of neural network partition methods and the goal is to partition the set of objects O into K disjoint clusters, where K is assumed to be known a priori. The algorism introduced by Macqueen draws an initial partition of the objects at random. It then computes the cluster centroids, assigns objects to the closest of them and iterates until a local minimum is obtained. The advantage of using neural network is that the spectra at the wavelengths having absorptions against chemical bonds including C-H and O-H types can be selected directly as input data. In conventional multiple regression approaches, the first wavelength is selected manually around the absorbance wavelengths as showing a high correlation coefficient between the NIR $2^{nd}$ derivative spectrum and Brix value with a single regression. After that, the second and following wavelengths are selected statistically as the calibration equation shows a high correlation. Therefore, the second and following wavelengths are selected not in a NIR spectroscopic way but in a statistical way. In this research, the spectra at the six wavelengths including 900, 904, 914, 990, 1000 and 1016nm are selected as input data for K-mean analysis. 904nm is selected because the wavelength shows the highest correlation coefficients and is regarded as the absorbance wavelength. The others are selected because they show relatively high correlation coefficients and are revealed as the absorbance wavelengths against the chemical structures by B. G. Osborne. The experiment was performed with two phases. In first phase, a reflectance was acquired using fiber optics. The reflectance was calculated by comparing near infrared energy reflected from a Teflon sphere as a standard reference, and the $2^{nd}$ derivative spectra were used for K-mean analysis. Samples are intact 67 apples which are called Fuji and cultivated in Aomori prefecture in Japan. In second phase, the Brix values were measured with a commercially available refractometer in order to estimate the result of K-mean approach. The result shows a partition of the spectral data sets of 67 samples into eight clusters, and the apples are classified into samples having high Brix value and low Brix value. Consequently, the K-mean analysis realized the classification of apples on the basis of the Brix values.

• Bulletin of the Korean Chemical Society
• /
• v.4 no.4
• /
• pp.183-188
• /
• 1983

Two major and two minor polyacetylenes were isolated from fresh white Korean ginseng roots. The petroleum ether-ethyl ether fractions containing the polyacetylene compounds were collected through solvent fractionation, partition and silica gel column chromatography. Further separation of polyacetylenic fractions was proceeded by bonded normal phase HPLC utilizing a moderately nonpolar microparticulate column. The low pressure liquid chromatography was used for the semi-preparative separation. The chemical structures of the two major polyacetylenes separated were determined by UV, IR, $^1H$ NMR, $^{13}C$ NMR, mass spectra and elemental analysis. One of them is identified to be heptadeca-1-en-4, 6-diyne-3, 9, 10-triol, a new structure, and the other is heptadeca-1, 9-dien-4, 6-diyn-3-ol, known as panaxynol.

• The Korean Journal of Food And Nutrition
• /
• v.24 no.4
• /
• pp.617-621
• /
• 2011

$Coptis$ $chinensis$ Franch rhizome is one of the important traditional Korea medicines with anti-inflammatory, anti-bacterial, anti-hypertensive and anti-cancer properties. The methanol extract of rhizome from the $Coptis$ $chinensis$ rhizome was purified by using preparative centrifugal partition chromatography (CPC) and HPLC method. The optimum two-phase CPC solvent system was composed of n-butanol:acetic acid:water at a ratio of 4:1:5. Berberine (16.8 mg) was successfully isolated by CPC and HPLC. The chemical structure of the compound was identified by (1 H)$^1H$, $^{13}C$-NMR and ESI-MS spectral data analysis.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.13 no.5
• /
• pp.2674-2697
• /
• 2019

Identity authentication is a crucial line of defense for network security, and passwords are still the mainstream of identity authentication. So far trawling password attacking has been extensively studied, but the research related with personal information is always sporadic. Probabilistic context-free grammar (PCFG) and Markov chain-based models perform greatly well in trawling guessing. In this paper we propose a systematic targeted attacking model based on structure partition and string reorganization by migrating the above two models to targeted attacking, denoted as TG-SPSR. In structure partition phase, besides dividing passwords to basic structure similar to PCFG, we additionally define a trajectory-based keyboard pattern in the basic grammar and introduce index bits to accurately characterize the position of special characters. Moreover, we also construct a BiLSTM recurrent neural network classifier to characterize the behavior of password reuse and modification after defining nine kinds of modification rules. Extensive experimental results indicate that in online attacking, TG-SPSR outperforms traditional trawling attacking algorithms by average about 275%, and respectively outperforms its foremost counterparts, Personal-PCFG, TarGuess-I, by about 70% and 19%; In offline attacking, TG-SPSR outperforms traditional trawling attacking algorithms by average about 90%, outperforms Personal-PCFG and TarGuess-I by 85% and 30%, respectively.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.48 no.3
• /
• pp.301-307
• /
• 2015

Phlorotannins and marine algal polyphenols, including dieckol, 6,6-bieckol, phloroglucinol, phlorofucofuroeckol-A, and eckol, were isolated from brown seaweeds. These compounds have beneficial bioactivities, and Ecklonia cava has become widely used for the extraction and isolation of phlorotannins. Eckol, in particular, has been to shown to have antioxidant, anti-inflammatory, anticoagulatory, and photoprotective properties. However, due to its low abundance in weaweed, the isolation and purification of eckol are difficult. Its limited availability renders the isolation and purification of eckol labor-intensive processes. Centrifugal partition chromatography (CPC) is an efficient technique for the isolation and purification of eckol. In this study, eckol was isolated from the ethyl acetate fraction of the 70% ethanol extract of E. cava using CPC with a two-phase solvent system of a n-hexane:EtOAc:methanol:water (2:8:3:7, v/v) solution. The purity and anti-inflammatory activity of the isolated eckol were verified by high-performance liquid chromatography and by assaying lipopolysaccharide-induced inflammatory responses in an immortalized murine BV2 microglial cell line, respectively. In conclusion, CPC is a useful technique for simple and efficient isolation of eckol from E. cava.

• Journal of Bio-Environment Control
• /
• v.4 no.2
• /
• pp.136-143
• /
• 1995

Using a PEG- dextran two phase partition method, plasma and intracellular membrane separated from microsomal membrane of canola (Brassica napus) leaves have been fractionated by centrifugation. $K^{+}$- ATPase specific activity in the plasma membrane (U$_2$ phase) of plants grown at $25^{\circ}C$ and 1$0^{\circ}C$ were 6.6 and 4.6 times, respectively that of the microsomal membrane. Plasma membrane had a lower cytochrome- c- oxidase specific activity than the microsomal membrane or intracellular membrane, while intracellular membrane (L$_2$ phase) had a high cytochrome-c- oxidase but little $K^{+}$- ATPase specific activity. The plasma membrane of canola grown at 1$0^{\circ}C$ had higher 18:3 to 18:2 (linolenic to linoleic acid) ratio (29.2% ) and higher degree of unsaturation than that grown at $25^{\circ}C$ The double bond index of plasma membrane from canola grown at 1$0^{\circ}C$ increased by 8.9% relative to canola grown at $25^{\circ}C$. Similar, intracellular membrane increased by 19.7% at 1$0^{\circ}C$. Canola grown at 1$0^{\circ}C$ was lower in chlorophyll contents (17.3%) than that grown at $25^{\circ}C$. These changes in fatty acid unsaturation were attributable largely to change in Cl8 fatty acid, with major changes occurring in linolenic acid (18 :3) which might have a physiological role of membrane to adaptation on low temperature.ure.

• Textile Coloration and Finishing
• /
• v.2 no.2
• /
• pp.33-38
• /
• 1990

Nitrocellulose [NC]-Poly(vinylamine) [PVAm] blended membranes with the change of amino group contents were prepared. The sorption and permeation of a mono-sulfonic acid dye, Orange II, in the membranes were investigated by the steady-state permeation method at $50^{\circ}C$ and pH 2.2. The results were discussed in the framework of dual sorption and diffusion theory. It was found that thesorption isotherms comprise a partition and two Langmuir type adsorption having similar binding constants. One of the latter sorption modes is due to unknown adsorption sites in NC and the other is due to the amino groups in PVAm. Apparent diffusion coefficients for collective P and L dye species, $D_P\; and D_L$, were obtained. Interpretation of $D_P$ values leads to two modes of partitions; one is such that dye is immobilized in NC and the other is the dissolution of the dye into the internal water phase.

• KSBB Journal
• /
• v.9 no.3
• /
• pp.279-286
• /
• 1994

A mathematical model has been derived and used to describe phosphoprotein partitioning in Fe(III) IDA-PEG/dextran two-phase systems. This model includes the inhibitory effects of hydrogen and hydroxyl ion concentrations on protein partitioning. For aqueous two-phase partitioning experiments, the Al and A2 subcomponents of ovalbumin carrying two and one surface phosphoryl group(s) were purified using an immobilized metal ion affinity chromatography (IMAC). The ratio of partition coefficients in the presence and absence of Fe(III)IDA-PEG, K/Ko, increased in the pH range of 3.0 to 5.0 due to deprotonation of the second oxygen of the phosphoryl group, and above pH 5.0 declined steeply by the inhibitory binding of hydroxyl ions to the metal ion. This partitioning behavior was well described by the mathematical model. The binding constants for formation of the complex between the phosphoryl group and the Fe(III)IDA-PEG were found to be $6.1{\times}10^3M^{-1} and 2.3{\times}10^4M^{-1}$ in the top and bottom phases, respectively. These values are 3-5 times those for interaction of Cu(II)IDA-PEG with a single surface-accessible histidine.