• Computers and Concrete
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• v.30 no.1
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• pp.33-42
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• 2022

Experimentally predicting the compressive strength (CS) of concrete (for a mix design) is a time-consuming and laborious process. The present study aims to propose surrogate models based on Support Vector Machine (SVM) and Gaussian Process Regression (GPR) machine learning techniques, which can predict the CS of concrete containing nano-silica. Content of cement, aggregates, nano-silica and its fineness, water-binder ratio, and the days at which strength has to be predicted are the input variables. The efficiency of the models is compared in terms of Correlation Coefficient (CC), Root Mean Square Error (RMSE), Variance Account For (VAF), Nash-Sutcliffe Efficiency (NSE), and RMSE to observation's standard deviation ratio (RSR). It has been observed that the SVM outperforms GPR in predicting the CS of the concrete containing nano-silica.

• Radiation Oncology Journal
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• v.9 no.1
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• pp.7-15
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• 1991

Pentoxifylline (PENTO) has been known to improve RBC fluidity, and thus improve the flux of RBC through narrow capillaries. Additionally, PENTO also decreases the $O_2$ affinity of hemoglobin by increasing 2,3-DPG levels, thereby increasing the $O_2$ release from RBC. Nicotinamide (NA) has been reported to decrease the number of acutely hypoxic cells in tumors by temporarily increasing tumor blood flow. Therefore, the purpose of this study was to examine whether the combination of PENTO and NA (PENTO+NA) would reduce the radioresistance of the Fsall murine fibrosarcoma by oxygenating the hypoxic cells. We obsewed a significantly enhanced radiation-induced growth delay of the FSaII tumors by PENTO+NA. Thus the enhancement ratio was between 2.5 and 2.8 in growth delay assay. The $TCD_{50}$ of control tumors was about 57 Gy, but that of PENTO+NA treated tumors was about 32Gy. Thus $TCD_{50}$ was modified by a factor of 1.8. We also observed that PENTO+NA exerted no effect on the radiation-induced skin damage after the legs without bearing tumors were exposed to X-irradiation. In order to clarify radiosensitizing effects of PENTO+ NA, changes in tumor blood flow and intratumor pOf were measured using laser Doppler flowmetry and $O_2$ microelectrode methods. The tumor blood flow significantly increased at 10 min. after injection of PENTO+ NA. Furthermore, we also found that PENTO+ NA significantly increased intratumor $pO_2$ from 8 to 19 mmHg. We concluded that PENTO+MA was far more effective than NA alone or PENTO alone. The increase in the response of tumors in vivo to X-irradiation appeared to be due mainly to an increase in the tumor oxygenation. Further studies using various concentrations of PENTO alone and in combination with NA to obtain better sequencing and maximal radiosensitization are warranted.

• Korean Journal of Food Science and Technology
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• v.13 no.1
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• pp.37-42
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• 1981

Polar lipids of the total lipid extracted from 4 representative varieties of barley grown in Korea and their corresponding malt were studied. The average content of glycolipids and phospholipids in barley were 8.9 and 17.3% and their average content of malt were 12.3 and 19.2%, respectively. Among the glycoliplds of the barley, digalactosyl diglycerides and monogalactosyl diglycerides were the major components, and the malts showed somewhat lower amounts of those components. Steryl glycosides and cerebrosides were the minor components of the glycolipids, and malts of the barley showed somewhat increased amounts of those components. Phosphatidyl cholines, lysophosphatidyl cholines, diphosphatidyl glycerols, and phosphatidyl ethanolamines were the major components of the phospholipids for the barley and represented 85 to 90% of the total phospholipids. The malts had lower amounts of phosphatidyl cholines and the lyso analog, and higher amounts of phosphatidyl ethnolamines and diphosphatidyl glycerols. The fatty acid composition in the glycolipids and phospholipids were similar to the pattern in those of the neutral lipids. But glycolipids and phospholipids fractions contained a higher percent of linoleic and palmitic acid than other lipid fractions, respectively.

• Elastomers and Composites
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• v.19 no.1
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• pp.13-31
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• 1984

The purposes of this dissertation are to demonstrate that DSC theromoanaytical methods of vulcanization can provide useful informations on the vulcanization characteristics of industrial formulations and also provides the potential basis for a rapid and complete method of sulfur and vulcanizing accelerator analysis for quality control. The influences of those factors such as heating rate, scan temperature, vucanizing accelerator's type and concentration upon vulcanization exotherm in NR and NBR compounds in the presence of vulcanizing accelerators such as TMTD,MBTS,DPG,TMTM,CBS, and MBT were evaluated by means of DSC. In order to examine the credibility in the DSC method, the same samples which were used for DSC method were studied to compare the DSC results with the ODR (Oscillating Disk Rheometer) data. The results obtained were as follows 1. In the DSC dynamic experiments, the observed enthalpy results from vulcanization depends upon the heating rate; In the range of 2 to $20^{\circ}C/min$ of heating rate, as the heating rate was increased the enthalpy change was also increased. However, over the heating rate of $30^{\circ}C/min$ it was observed that the enthalpy change was decreased as the heating rate was further increased. Without regard to the change of enthalpy, tremendous instantaneous heat evolving was observed in the range of high heating rates. 2. For the samples which are added with various vulcanizing accelerators, the activation energies of vulcanization were as follows; 3. Regarding to the influences of vulcanizining accelerator's types upon the characteristics of vulcanization exotherm, NR and NBR compounds in the presence of thiuramsulphide compounds type accelerators such as TMTD, TMTM, were exhibited sharper and higher vulclanization exotherm than others. From the resuts of DSC thermograms which was distributed in even shape in the broad temperature range, it was clearly shown that the guanidine compounds type accelerator such as DPG acts as a delayed acting accelerator. 4. In the comparison of DSC and ODR results, the dependency of temperature in the cure rate and the observed conversions show good agreements between two results. 5. In the same curatives, by the comparison of glass transition temperatures, it was possible to predict relative values of maximum torques. Consequently, from the present studies, it is shown that the DSC thermoanalytical method can provide an alternate new method for rapid and complete quality control analysis of rubber industry.

• Journal of the Korean Applied Science and Technology
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• v.25 no.4
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• pp.477-484
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• 2008

It is inevitable to use chemical germicidal agents like paraben, imidazolidinyl urea and phenoxyethanol to preserve the emulsions which is usually used in cosmetics. Although these chemical preservatives are good enough to reduce the microbiological contamination, they are irritative, allergenic to the skin. Several kinds of polyols are used in cosmetics as moisturizer and solvent. In this study, we evaluate the effects of polyols on anti-microbial activities, safety and resistant index. MIC(minimal inhibitory concentration) of polyols determined against 6 germs including Staphylococcus aureus. The order of MIC was PG $\cong$ DPG $\cong$ 1,3BG > HG > 1,2-PD > 1,2-HD $\cong$ 1,2-OD. The $2{\sim}3\;wt%$ of 1,2-HD(hexanediol) shows good anti-microbial effects in emulsions without allergenic response. Resistant index of 1,2-HD was less than 2 and this value was smaller than that of chemical preservatives. The mechanism of antimicrobilogical effect might be disturb the membrane of germs by investigating using electron microscope. Added to that, using this paradigm, low preservative contents, paraben-free system, and even preservative-free systems can be expected from these results.

• Journal of Korea Multimedia Society
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• v.7 no.7
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• pp.922-933
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• 2004

In recent years, peer-to-peer network have a greate deal of attention for distributed computing or collaborative application, and work of ID-based public key systems have been focusing on the area of cryptography. In this paper, we propose ID-based group key management protocols for secure communication in autonomous peer group. Each member obtains his public/private key pair derived from his identification string from Private Key Generator. No central server participates in group key management protocol instead, all group members share the burden of group key management by the collaboration of themselves, so that our scheme avoids the single point of failure problem. In addition, our scheme considers the nature of dynamic peer group such as frequent joining and leaving of a member.

• Advances in nano research
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• v.12 no.6
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• pp.629-638
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• 2022

This work shows the impregnation of scents using a graphene sponge (GS). This was functionalized by the modified Hummers method, pursuing to add different functional groups. It is proposed to achieve the release and seek to control it through electrical potential applied to the graphene sponge with essential oils. The graphene sponge was functionalized and steeped with two kinds of oil. The electrochemical study demonstrates the variation in the electrochemical behaviour of the functionalized graphene sponge without and impregnated with oil. The release of the oil and its aromatic scents was carried out by applying an electrical potential of 30 V, with a release rate of 1.86 mg/min. The heating of the sample that causes the release of oil, associated with the electrical resistance of the system, reaches temperatures of about 150℃. The essential oils, graphene sponge, surfactant, graphene sponge with essential oils, graphene sponge recuperated after applying electric potential, graphene sponge recovered by temperature and dipropylene glycol (DPG) were characterized using Fourier transformed infrared spectroscopy (FTIR), digital microscopy, and x-ray photoelectron spectroscopy (XPS).

• KDI Journal of Economic Policy
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• v.19 no.2
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• pp.213-268
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• 1997

일국(一國)의 경제발전(經濟發展)은 경제적 진보와 근대화를 수반하는 역사적 현상이지만 구체적으로는 산업구조(産業構造)의 변화(變化)에 의한 생산(生産)과 소득(所得)의 증가(增加)라는 측면을 가지고 있다. 한국과 일본의 경제발전과정에 수반되는 경제성장과 산업구조변화에 대한 요인을 비교 분석하는 것은 양국경제의 발전현상을 이해하고, 향후의 경제정책에 기초적인 정보를 제공할 수 있다는 점에서 그 중요성이 있을 것이다. 따라서 본고는 "비례적(比例的) 성장(成長)으로부터의 편차(偏差)(DPG)" 방법을 일본의 경우는 1915~90년, 한국은 1960~90년까지의 장기적인 산업연관자료에 적용하여 양국의 산업성장과 산업생산구조변화에 대한 요인을 수요측면에서 비교 분석하였는바, 그 결과는 다음과 같이 요약된다. 우선 양국경제의 산업생산구조 및 주도산업의 변화는 시기에 있어서 차이를 보이지만 분석기간중 양국 모두에서 농림수산업은 계속해서 생산비중이 줄어들고 있고, 경제성장을 주도한 산업이 경공업에서 중화학공업으로, 그리고 중화학공업에서도 중공업으로 이전된 것으로 나타났다. 일본의 경우는 1970년대에는 생산자서비스부문을 중심으로, 그리고 1980년대에는 소비자서비스부문을 중심으로 "경제의 서비스화"가 진전되어 서비스산업이 주도산업으로 부상되고 있으나, 한국경제에서는 1990년까지도 서비스산업의 확대가 관측되지 않고 있다. 이러한 결과는 향후 한국경제의 산업생산구조에 있어서 서비스산업의 중요성이 점차 커질 것이며, 특히 "경제의 서비스화"가 생산자서비스부문을 중심으로 이루어질 가능성이 높다는 것을 시사한다. 한편 양국의 성장패턴을 살펴보면, 일본의 경우는 시기별로 성장요인에 많은 변화가 있었으나 대체로 수출보다는 국내수요(國內需要)가 경제성장에 중요한 역할을 한 것으로 나타났다. 그러나 한국경제의 성장의 성장에는 수출과 투자의 역할이 중요했으며, 특히 수출은 분석기간중 지속적으로 정(正)의 효과(效果)만을 보여 경제성장의 견인차역할을 한 것으로 나타났다. 1980년대까지 한국경제의 성장에 있어서는 수입대체보다는 수출확대를 통한 중화학공업의 육성이 지대한 영향을 미쳤으며, 이러한 수출주도적인 중화학공업의 성장패턴은 현재 국내수요(國內需要)의 규모(規模)와 산업구조변화를 일본의 경우에 비추어볼 때, 향후 몇 년 동안은 크게 변화하지 않을 것으로 판단된다.

• The Transactions of the Korea Information Processing Society
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• v.6 no.5
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• pp.1280-1290
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• 1999

Applying the change impact analysis to the distributed environment is not straightforward since it is based on the centralized system environment. In this paper, we investigate the change impact analysis of object-oriented shoftwares in the distributed environment. We first, categories the types of changes common in object-oriented software into three sets: data, method, and class level changes. We, then, analyze the impact of each set of changes and represent it in the form of a DPDG. A DPDG is a graph showing relationship of object oriented softwares - with data elements. classes, design documents, servers - in the distributed environment. DPDG searches element of software to retest when the software is changed. Thus, DPDG saves effort of software to retest. In this paper, We propose the table of firewall for retest elements that be discovered by DPDG and implement the table of firewall. The table of firewall is used VIST that we design a software testing tool. The VIST utilizes the minimized firewall, then saves efforts and costs of retesting for distributed object-oriented software.

• Journal of Microbiology and Biotechnology
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• v.32 no.7
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• pp.855-861
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• 2022

A white-pigmented, non-motile, gram-negative, and rod-shaped bacterium, designated CYS-02^T, was isolated from soil sampled at Suwon, Gyeonggi-do, Republic of Korea. Cells were strictly aerobic, grew optimally at 20-28℃ and hydrolyzed Tween 40. Phylogenetic analysis based on 16S rRNA gene sequence indicated that strain CYS-02^T formed a lineage within the family Comamonadaceae and clustered as members of the genus Variovorax. The closest members were Variovorax guangxiensis DSM 27352^T (98.6% sequence similarity), Variovorax paradoxus NBRC 15149^T (98.5%), and Variovorax gossypii JM-310^T (98.3%). The principal respiratory quinone was Q-8 and the major polar lipids contain phosphatidylethanolamine (PE), phosphatidylethanolamine (PG), and diphosphatidylglycerol (DPG). The predominant cellular fatty acids were C_16:0, summed feature 3 (C_16:1ω7c and/or C_16:1ω6c) and summed feature 8 (C_18:1ω7c and/or C_18:1ω6c). The DNA GC content was 67.7 mol%. The ANI and dDDH values between strain CYS-02T and the closest members in the genus Variovorax were ≤ 79.0 and 22.4%, respectively, and the AAI and POCP values between CYS-02^T and the other related species in the family Comamonadaceae were > 70% and > 50%, respectively. The genome of strain CYS-02^T showed a putative terpene biosynthetic cluster responsible for antioxidant activity which was supported by DPPH radical scavenging activity test. Based on genomic, phenotypic and chemotaxonomic analyses, strain CYS-02^T was classified into a novel species in the genus Variovorax, for which the name Variovorax terrae sp. nov., has been proposed. The type strain is CYS-02^T (= KACC 22656^T = NBRC 00115645^T).