• Journal of Korea Multimedia Society
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• v.8 no.11
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• pp.1520-1530
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• 2005

As XML is recognized as a prevalent standard for document representation and exchange in the Internet, the need for security of XML becomes very important issue. Until now researches on XML security have been focused on confidentiality or integrity like encryption and digital signature technology. But, as XML data becomes more massive and complicated, it requires managerial security that decided access permit or deny by the authority oi user who is using the XML data. Thus it requires models and mechanisms enabling the specification and enforcement of access control policies for XML documents. In this paper, we suggest the new access control model and mechanism that separate XML documents by access level, assign roles to each user by applying Role Based Access Control (RBAC) and perform access control to specific documents by encrypting each section with roles. The method, we suggested, has an advantage that it does not need to update the whole keys used in encryption process by updating only the relations between appropriate secure layers.

• Corrosion Science and Technology
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• v.14 no.1
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• pp.1-11
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• 2015

Local wall thinning and integrity degradation caused by several mechanisms, such as flow accelerated corrosion (FAC), cavitation, flashing and/or liquid drop impingements, are a main concern in carbon steel piping systems of nuclear power plant in terms of safety and operability. Thinned pipe management program (TPMP) had been developed and optimized to reduce the possibility of unplanned shutdown and/or power reduction due to pipe failure caused by wall thinning in the secondary side piping system. This program also consists of several technical elements such as prediction of wear rate for each component, prioritization of components for inspection, thickness measurement, calculation of actual wear and wear rate for each component. Decision making is associated with replacement or continuous service for thinned pipe components. Establishment of long-term strategy based on diagnosis of plant condition regarding overall wall thinning is also essential part of the program. Prediction models of wall thinning caused by FAC had been established for 24 operating nuclear plants. Long term strategies to manage the thinned pipe component were prepared and applied to each unit, which was reflecting plant specific design, operation, and inspection history, so that the structural integrity of piping system can be maintained. An alternative integrity assessment criterion and a computer program for thinned piping items were developed for the first time in the world, which was directly applicable to the secondary piping system of nuclear power plant. The thinned pipe management program is applied to all domestic nuclear power plants as a standard procedure form so that it contributes to preventing an accident caused by FAC.

• Journal of Broadcast Engineering
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• v.16 no.5
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• pp.722-737
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• 2011

In this paper, we propose an estimation of network jitter that occurs when transmitting TCP packets containing MPEG-2 TS in progressive streaming service over wired or wireless Internet networks. Based on the estimated network jitter size, we can calculate required de-jitter buffering time to absorb the network jitter at the receiver side. For this purpose, by exploiting the PCR timestamp existing in the TS packet header, we create a new timestamp information that is marked in the optional field of TCP packet header to estimate the network jitter. By using the proposed de-jitter buffering scheme, it is possible to employ the conventional T-STD buffer model without any modification in the progressive streaming service over IP networks. The proposed method can be applicable to the recently developed international standard, MPEG DASH (dynamic adaptive streaming over HTTP) technology.

• Transactions of the KSME C: Technology and Education
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• v.3 no.3
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• pp.233-240
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• 2015

Analysis of the aerodynamic performance of a bobsleigh has been performed for various types of bobsleigh body shape. To analyze the aerodynamic performance of the bobsleigh, three-dimensional Reynolds-averaged Navier-Stoke equations were used with the standard k-${\varepsilon}$ model as a turbulence closure. Grid structure was composed of unstructured tetrahedral grids. The radii of curvature of cowling, and height and length of front bumper at the tip on the drag coefficient were selected as geometric parameters. And, the effects of these parameters on the aerodynamic performance, i.e., the drag coefficient, were evaluated. The results shows that the aerodynamic performance is significantly affected by the height of front bumper and radius of curvature.

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.1
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• pp.67-73
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• 2016

This study analyzed the state of the vessels which were using the berth for dangerous goods more than its carrying capacity in the major dangerous cargo handling port of Ulsan in Korea, The result of the analysis showed that a ship which has 3 times more than the maximum berthing capacity was moored at berth. Accordingly, a simulation model for 50,000 DWT berth was built and carried out the mooring safety analysis with 50,000 DWT, 70,000 DWT and 100,000 DWT vessels by mooring assessment program. The evaluation was carried out according to the standard environment presented in OCIMF standards. 50,000 DWT vessel was evaluated to meet the acceptable criteria but, 70,000 DWT and 100,000 DWT vessels exceeded the acceptable limit as per external conditions. Consequently, safe mooring guidelines were suggested and also proposed the building of common 'Mooring safety guideline' for port with assessment of different cases.

• Horticultural Science & Technology
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• v.33 no.4
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• pp.559-565
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• 2015

The rind phenotype of watermelon fruits is an important agronomic characteristic in the watermelon market. Inheritance and linkage analyses were performed for three rind-related traits that together determine the rind phenotype: foreground stripe pattern, rind background color, and depth of rind color. The inheritance of the foreground stripe pattern was analyzed using three different $F_2$ populations, showing that the striped pattern is dominant over the non-striped pattern. The inheritance analysis of the rind background color was performed using $F_2$ populations of the '10909' and '109905', and the depth of rind color was analyzed using $F_2$ populations of the '90509' and '109905'. Yellow color was found to be dominant over green color, and a deep color was dominant over the standard color. Linkage analysis of the three traits was conducted using three $F_2$ populations in which two traits were segregating. Each pair of traits was inherited independently, which demonstrated that the three traits are not linked. Therefore, we propose a three-locus model for the determination of rind phenotype, providing novel insight that rind phenotype is determined by the combination of three genetically independent loci.

• Journal of Technologic Dentistry
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• v.34 no.4
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• pp.353-359
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• 2012

Purpose: The aim of this study measured and compared the marginal and internal fit of metal cores with two base metal alloy (Ni-Cr alloy(non-beryllium), Co-Cr alloy). Methods: Maxillary right first molar abutment fabricated by titanium was prepared for this study. Impressions(10ea) were made from titanium model, and study models were poured with improved dental stone. Wax cores of twenty were prepared for burn-out and casting. Ten wax cores cast Ni-Cr alloy(non-Be), and finally ten cast Co-Cr alloy. Marginal and internal fit of cores was evaluated using silicone replica technique and digital microscope(x160). The data were statistically analyzed with the independent samples t-test (${\alpha}$ <.05). Results: Mean(standard deviation, SD) marginal and internal fit total size of Ni-Cr alloy(non-Be) group was $73.3(14.4){\mu}m$ and of Co-Cr alloy group $65.6(17.4){\mu}m$. The marginal and internal fit total size of Ni-Cr alloy group(non-Be) was statistically significantly greater than that of Co-Cr alloy group (P=.004). Conclusion: Co-Cr alloy cores in this study had a better marginal fit than Ni-Cr alloy(non-Be) cores.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.1
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• pp.106-115
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• 2018

Objective: The goal of this study was to investigate the effects of dietary standard ileal digestible (SID) valine:lysine ratios on performance, intestinal morphology, amino acids of liver and muscle, plasma indices and mRNA expression of branched-chain amino acid (BCAA) metabolism enzymes. Methods: A total of 144 crossbred pigs (Duroc${\times}$Landrace${\times}$Large White) weaned at $28{\pm}4days$ of age ($8.79{\pm}0.02kg$ body weight) were randomly allotted to 1 of 4 diets formulated to provide SID valine:lysine ratios of 50%, 60%, 70%, or 80%. Each diet was fed to 6 pens of pigs with 6 pigs per pen (3 gilts and 3 barrows) for 28 days. Results: Average daily gain increased quadratically (p<0.05), the villous height of the duodenum, jejunum and ileum increased linearly (p<0.05) as the SID valine:lysine ratio increased. The concentrations of plasma ${\alpha}-keto$ isovaleric and valine increased linearly (p<0.05), plasma aspartate, asparagine and cysteine decreased (p<0.05) as the SID valine:lysine ratio increased. An increase in SID lysine:valine levels increased mRNA expression levels of mitochondrial BCAA transaminase and branched-chain ${\alpha}-keto$ acid dehydrogenase in the longissimus dorsi muscle (p<0.05). Conclusion: Using a quadratic model, a SID valine:lysine ratio of 68% was shown to maximize the growth of weaned pigs which is slightly higher than the level recommended by the National Research Council.

• The korean journal of orthodontics
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• v.44 no.2
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• pp.69-76
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• 2014

Objective: This study aimed to evaluate the accuracy and precision of polyurethane (PUT) dental arch models fabricated using a three-dimensional (3D) subtractive rapid prototyping (RP) method with an intraoral scanning technique by comparing linear measurements obtained from PUT models and conventional plaster models. Methods: Ten plaster models were duplicated using a selected standard master model and conventional impression, and 10 PUT models were duplicated using the 3D subtractive RP technique with an oral scanner. Six linear measurements were evaluated in terms of x, y, and z-axes using a non-contact white light scanner. Accuracy was assessed using mean differences between two measurements, and precision was examined using four quantitative methods and the Bland-Altman graphical method. Repeatability was evaluated in terms of intra-examiner variability, and reproducibility was assessed in terms of interexaminer and inter-method variability. Results: The mean difference between plaster models and PUT models ranged from 0.07 mm to 0.33 mm. Relative measurement errors ranged from 2.2% to 7.6% and intraclass correlation coefficients ranged from 0.93 to 0.96, when comparing plaster models and PUT models. The Bland-Altman plot showed good agreement. Conclusions: The accuracy and precision of PUT dental models for evaluating the performance of oral scanner and subtractive RP technology was acceptable. Because of the recent improvements in block material and computerized numeric control milling machines, the subtractive RP method may be a good choice for dental arch models.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2006.11a
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• pp.390-395
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• 2006

Recently, construction industry demands have been changed by domestic construction circumstances such as high-technology, mega-projects, and the complexity of construction. In order to deal with the change of such a domestic construction circumstances, the Ministry of Construction and Transportation (MOCT) has introduced advanced delivery methods (i..e, CM, DB, etc.). However, the advantages and disadvantages of the advanced delivery methods have not been effectively applied for previous projects. The reason for this is that the "Reviewing Standard for the Large-scale Construction Bidding Method" has not reflected enough project characteristics when the delivery method is selected in the project planning phase. Therefore, this paper proposes the model for selecting criteria of delivery method based on project characteristics in the Multi-housing projects.