• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.3
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• pp.545-551
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• 2012

In this paper, we propose a new cryptosystem based on the IQC depended on the complexity of class number and intractibility of factoring integer, and introduce two algorithm which reduce encryption and decryption times. To recognize the security of the cryptosystem, we take a simple example to analyze the complexities of public key and secret key and then introduce the operating process of the cryptosystem.

• The Journal of the Korea institute of electronic communication sciences
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• v.6 no.1
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• pp.90-96
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• 2011

In this paper, we propose a new discrete logarithm problem(DLP) based on the class semigroups of imaginary quadratic non-maximal orders using the special character of non-invertible ideal and analysis its security. To do this, we first explain the mathematical background explicitly and prove some properties of Cls (O) which relate to constructing the DLP and guaranteeing the security. To test the security of the proposed DLP, we compare the class number of the maximal order with that of the non-maximal order and investigate the unique factorization problems of ideals between class groups of the maximal orders and class semigroups of non-maximal orders to ensure the security of the cryptosystem.

• Korean Journal of Pharmacognosy
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• v.43 no.4
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• pp.297-301
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• 2012

In the course of screening for antioxidant compounds by measuring the radical scavenging effect on 1,1-diphenyl-2-picrylhydrazyl (DPPH), a total extract of the twigs of Taxillus delavayi (Loranthaceae) was found to show potent radical scavenging activity. Subsequent activity-guided fractionation of the methanolic extract led to the isolation of two phenolic compounds, catechin (1) and galloyl catechin (2), as active principles. Their structures were elucidated by spectroscopic studies. These two compounds showed the significant antioxidative effects on DPPH, and riboflavin- and xanthin-originated superoxide quenching activities. And these two compounds also showed strong nitric oxide radical scavenging effects. In riboflavin- and xanthin-originated superoxide quenching activities and nitric oxide radical scavenging effect, compound 2 showed better antioxidant activities than vitamin C.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.6
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• pp.1181-1188
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• 2017

The unit and fundamental units of number fields are important to number field sieves testing primality of more than 400 digits integers and number field seive factoring the number in RSA cryptosystem, and multiplication of ideals and counting class number of the number field in imaginary quadratic cryptosystem. To minimize the time and space in H/W implementation of cryptosystems using fundamental units, in this paper, we introduce the Dirichlet's unit Theorem and propose our process of generating the fundamental units of the number field. And then we present the algorithm generating our fundamental units of the number field to minimize the time and space in H/W implementation and implementation results using the algorithm over the number field.

• KSBB Journal
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• v.11 no.5
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• pp.577-585
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• 1996

Effects of various factors on the phenol degradation by activated sludge immobilized with the photo-crosslinked resin were investigated. The optimum pH on the degradation of phenol in both free and immobilized activated sludge was 7. When the pH of the reaction was varied from 5 to 10, the relative activity of the phenol degradation by the immobilized activated sludge was higher than that by the free activated sludge. A higher rate of phenol degradation was observed when a bead size was smaller. The phenol degradation in the free activated sludge was inhibited at the 3000 mg/L of phenol, while that in the immobilized activated sludge was maintained at the same concentration for 28 hrs without an inhibition. The degradation rates of phenol were not directly proportional to the increasing amount of immobilized beads dosage, but the phenol degradation was made in a rather short time than that for a free sludge system. The relative activities of the immobilized activated sludge after 7 runs of repeated reactions increased about 8 times as that of the first reaction. The activities for the phenol degradation remained stable for at least 80 days when the immobilized activated sludge was stored at an aerobic condition in the wastewater containing phenol. The loading rate as high as 5.59 kg-pheno1/㎥.d could have been achieved during the continuous treatment of phenol by the immobilized activated sludge.

• Journal of Chest Surgery
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• v.34 no.8
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• pp.611-614
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• 2001

To determine the efficacy and safety of endoscopic resection and ablation of superficial varicosities using a powered vein resector, irrigated illuminator. Material and Method: 83 consecutive patients were involved in the study. 103 limbs in 83 patients were treated using a minimal invasive, powered, vein resecting devide with cutaneous transillumination and tumescent anesthesia technique. There were 51 women and 32 men. All patients were operated under general anesthesia or regional anesthesia. Operative time and patient satisfaction scores were recorded along with the number of incisions made. Result: 83 patients(51/61.4% female, 32/38.6% male, aged 25-78 years) had varicose vein. Average age at the time of operation was 45 years(range, 25 to 78 years). There were 63 unilateral procedures and 20 bilateral operations. Operative time ranged from 24 to 46 minutes (average 35.3 minutes) in the unilateral procedure. The number of incisions per limb averaged 2.7(range, 2 to 5). Postoperative complications occurred in 7(8.4%) patients. Patients were asked to describe their pain on an analog scale ranging form 1 to 10 with r representing no pain and 10 worst imaginable pain. Immediately postoperative pain score was 2.4 Postoperative pain score at 72 hours had a mean score of 2.0. Postoperative pain score at 1 months were 1. Conclusion: Varicose vein removal using Transilluminated Powered Phlebectomy(TIPP) is a safe and efficient procedure. The procedure saves time, is easy to perform, and gives direct visualization and a distinct endpoint of the removal of veins. It is also less tedious to perform and gives good cosmetic results with significant pain relief.

• Food Science and Preservation
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• v.23 no.5
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• pp.605-613
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• 2016

The quality and shelf life of sliced root of Platycodon grandiflorum (Doraji) treated by ozon-microbubble-heat shock (OMH) were investigated by combining modified-atmosphere packaging [MAP, ($50%O_2+15%CO_2+35%N_2$)]. The study was based on microbiological (total viable bacteria, fungi, Enterobacteriaceae and coliforms numbers), physicochemical and sensory changes. OMH treatment was effective in reducing microbial populations of the sliced Doraji, especially Enterobacteriaceae and coliforms reduced by 2 log CFU/g. However OMH-MAP treatment remained the aerobe and fungi numbers. Regarding the color, OMH-MAP delayed the change of Hunter $b^*$ and the sliced Doraji by OMH-MAP treatment exhibited lower decrease of flavor and overall acceptability compared to those by polypropylene packaging after tap water treatment (Control). The OMH and $50%O_2+15%CO_2$ MAP treatment gave better sensory quality and extended shelf-life for sliced Doraji (~3 days longer shelf-life than Control). Flavor was significantly related to overall acceptability at both Control and OMH-MAP, whereas total coliforms prevalence was associated with overall acceptability at only OMH-MAP. Therefore microbubble-heat shock treatment may improve microbial safety and sliced Doraji by OMH treatment can stored under $50%O_2+15%CO_2$ treatment for up to 7 days. Thus, OMH and MAP treatment may be used in maintaining the storage quality and marketability of sliced Doraji.