• Smart Structures and Systems
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• v.24 no.2
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• pp.243-256
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• 2019

Determination of the most meaningful structural modes and gaining insight into how these modes evolve are important issues for long-term structural health monitoring of the long-span bridges. To address this issue, modal parameters identified throughout the life of the bridge need to be compared and linked with each other, which is the process of mode tracking. The modal frequencies for a long-span bridge are typically closely-spaced, sensitive to the environment (e.g., temperature, wind, traffic, etc.), which makes the automated tracking of modal parameters a difficult process, often requiring human intervention. Machine learning methods are well-suited for uncovering complex underlying relationships between processes and thus have the potential to realize accurate and automated modal tracking. In this study, Gaussian mixture model (GMM), a popular unsupervised machine learning method, is employed to automatically determine and update baseline modal properties from the identified unlabeled modal parameters. On this foundation, a new mode tracking method is proposed for automated mode tracking for long-span bridges. Firstly, a numerical example for a three-degree-of-freedom system is employed to validate the feasibility of using GMM to automatically determine the baseline modal properties. Subsequently, the field monitoring data of a long-span bridge are utilized to illustrate the practical usage of GMM for automated determination of the baseline list. Finally, the continuously monitoring bridge acceleration data during strong typhoon events are employed to validate the reliability of proposed method in tracking the changing modal parameters. Results show that the proposed method can automatically track the modal parameters in disastrous scenarios and provide valuable references for condition assessment of the bridge structure.

• Korean journal of food and cookery science
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• v.7 no.4
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• pp.41-49
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• 1991

The objective of this study was to evaluate the effect of the Shinggumchopyun when the making of Shinggurnchopyun with the several kinds of sweeteners and amount of water on the texture. The evaluation of these results were as followings: 1. The standard recipes of Shinggurnchopyun were three cases. The first case was rice powder 350g, Shinggurnchopyun powder 7g, sugar 50g, water 90$m\ell$l. The second case was rice powder 350g, Singamcho powder 7g, syrup 50$m\ell$, water 60$m\ell$. The third case was rice powder 350g, Singamcho powder 7g, syrup 50$m\ell$, water 60$m\ell$. 2. According to the sensory evaluation, there were significant differences of appearance, softness, moistness and over all quality among samples. And there were no significant differences of color, flavor, grain and chewiness among samples. 3. The moisture contents of Singgamchopyun were (syrup) 40.14%, (honey) 41.17%, (sugar) 43.46%. 4. Judging from the results of Instron Universal Testing Machine, it was found that there were no significant differences in each treatment of the Cohesiveness, Springiness, Gumminess, Chewiness of Singamchopyun without only hardness.

• The Journal of Society for e-Business Studies
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• v.7 no.1
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• pp.35-50
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• 2002

Recently, payment method is one of the most hot issues for transaction of contents in mobile and internet markets. Many kinds of mobile contents services are rapidly growing with the combination of internet application services. Payment method algorithms are demanded for the stable transaction between producer and consumer. Security protocol algorithms are widely adapted for mobile Platform terminals. In this Paper, we described security mechanism for the current wireless internet services and compared with the performance result. There are security protocols that based on java machine platform or WAP protocols. The system is based on J2ME technology for the java mobile platform. Based on this technology, a security system is proposed for the service of mobile commerce electronic payment. The system is designed for the stability of transaction so that it enables to apply into many kinds of internet payment system.

• The Journal of Korean Academy of Prosthodontics
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• v.24 no.1
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• pp.33-43
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• 1986

The purpose of this study was to compare the wear resistance of heat pressure-cured microcomposite(SR-Isosit-N), photo-cured microcomposite(Dentalcolor), unfilled heat-cured resin(Thermojel) and that of human enmel. Specimens were made with specially designed die and finally polished with #3,000 diamond paste. After 100,000 strokes of tooth brushing at electric tooth-brushing machine, mean thickness loss of each specimen was measured by using surface profile and integration. The results were as follows 1. Mean thickness loss were $84.3{\pm}27.3{\mu}m$ in unfiled heat-cured resin, $9.4{\pm}2.5{\mu}m$ in photocured microcomposite, $7.6{\pm}2.1{\mu}m$ in heat.pressure-cured microcomposite and $0.97{\pm}0.42{\mu}m$ in enamel. 2. Heat.pressure-cured microcomposite and photo-cured microcomposite had no difference in mean thickness loss(p>0.05). 3. Unfilled resin and microcomposite had much differences in mean thickness loss (p<0.005). 4. ha resins used in this experiment had too much mean thickness loss as compared with enamel (p<0.005).

• Journal of Technologic Dentistry
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• v.37 no.1
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• pp.9-15
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• 2015

Purpose: The purpose of this study was to compare the accuracy of the maxillary three-unit fixed dental prosthesis (FDPs) made using two CAD/CAM milling machines : DCM Group(Dentaim CAD/CAM milling machine), WCM Group(Wieland CAD/CAM milling machine). Methods: Each of 10 duplicate models was scanned by blue light scanner(Identica, Medit, Korea), and the three-unit FDPs (STL file) was designed using DelcamCAD. A total of 20 three-unit FDPs was fabricated, comprising 2 groups of 10 specimens each (shrinkage ratio is 1:1). The first three-unit FDPs STL file was used as a CAD reference model (CRM). Obtained STL files by scanning the inner surface of three-unit FDPs were convened into the point clouds-ASC II files. Discrepancies between the point clouds and CRM were measured by superimposition software. Statistical methods to analyze the data were used non-parametric method. The mean (SD) values were compared by a Mann-Whitney U-test. Type one error rate was set at 0.05. Results: WCM group had small discrepancies with $2.17{\mu}m$ of mean value compared to $4.44{\mu}m$ in DCM group. The accuracy values between the two groups showed a sratistically significant difference (Table 2, p<.05). Conclusion: The accuracy of the three-unit fixed dental prosthesis(FDPs) made of two CAD/CAM milling machines were statistically different. Accuracy with which the prosthesis made of WCM group was superior.

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 2001.06a
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• pp.1285-1285
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• 2001

For NIR measurements of papers normally diffuse reflectance accessories are used which can provide a large sampling area. The in-line process control FT-NIR spectrometer MATRIX-E enables the contactless measurement of paper samples of low silicone coat weights on label-stocks in a paper converting factory. For this study concentrations of silicone between 0 and 2 g/$m^2$ on various paper substrates were included in a quantitative method. The aim was to achieve an absolute value for the deviation from the target value of 1 g/$m^2$ during continuous movement of the paper with velocities around 400 numinute. Influences from the uncoated paper type due to supplier, color, opacity, area densities, pre-coating as well as different compounds of the agent silicone were investigated and it was found that all these papers can be represented in one PLS-model. Especially the fact that silicone as an element is present in clay coated papers is of no consequence to the measurements with MATRIX-E. Moreover during in-line installations the variation of the moisture contents in the moving paper due to variable machine velocities as well as the reflecting material of the cylinder have to be considered. It is shown that the result of the in-line calibration has the same prediction ability compared to lab scale results(Root Mean Square Error of Cross-Validation RMSECV = 0.034 g/$m^2$).

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.208-208
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• 2017

No-tillage practices are expected to provide several benefits such as increasing soil organic matter, reducing labor time and saving energy cost compared with conventional tillage practices. This study was conducted to investigate the effects of no-tillage dry-seeding on rice growth and soil properties in comparison with other rice cultivation methods, machine transplanting and wet-hill-seeding on puddled paddy. Rice seedling establishment was slightly higher in no-tillage dry-seeding treatment ($145seedling\;m^{-2}$) than wet-hill-seeding on puddled paddy treatment ($111seedling\;m^{-2}$), but the seedling establishment in both treatments fell within the optimum range for direct seeding rice cultivation. Plant height, number of tillers and chlorophyll content (SPAD value) of rice in no-tillage dry-seeding treatment were higher than those of the other treatments. However, no significant differences in grain yield was observed among three cultivation methods, and the yield ranged 5.8 to $5.9ton\;ha^{-1}$. The heading date from seeding under no-tillage dry-seeding treatment was on average 109 days, which was similar to that under machine transplanting treatment (112 days), but 10 days later than that under wet-hill-seeding on puddled paddy treatment (99 days). Grain quality characteristics grown in no-tillage dry-seeding were similar to those grown in the other cultivation methods. These results indicate that no-tillage dry-seeding practice is comparable to conventional tillage system in terms of seedling establishment, growth, yields and grain quality.

• Journal of the Korean Society for Railway
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• v.19 no.2
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• pp.213-223
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• 2016

Traffic jams occur frequently due to the dense populations of cities. Accordingly, the discomfort of citizens has increased. In order to minimize traffic inconveniences, various public transportation facilities have been suggested. In this paper, for the economical construction of a near-surface railway system, the design of a trench shield is developed and a review of its applicability is done by creating and testing trench shield equipment on a small scale. The trench shield consists of an excavation part, a shield part and an advancement part. To examine the applicability of the trench shield, a laboratory test is carried out. The results of the laboratory test confirm the possibility of reducing the construction time at open-cut construction sites through the excavation of the trench shield. Although the laboratory test is an indoor and relatively small-scale experiment, it is considered to be possible to secure a construction speed of 3m/day when the trench shield equipment is used.

• Restorative Dentistry and Endodontics
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• v.25 no.1
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• pp.109-115
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• 2000

This study was designed to evaluate the microhardness of restorative composite resin and dual-cured composite resin cement which were light cured through the 1.5mm thickness composite overlay. For restorative materials, Z100 and Tetric Ceram were used. For dual cured composite cements, Variolink II((VL II) of three consistency (low, high, ultra high) were used. To determine the optimal microhardness of Z100, Tetric Ceram and Variolink II, each material was packed into the 1mm thickness teflon mold without composite overlay and light cured for 60 seconds. Then the microhardnesses of each sample were measured, averaged and regarded as optimal hardness of each material. To evaluate the microhardness of restorative composite resin and dual-cured composite resin cement which were light cured through the 1.5mm thickness composite overlay, the composites were packed into 1mm thickness teflon mold, coverd with celluloid strip, and then precured composite overlay which was made of Targis(Ivoclar/Vivadent, Liechtenstein) was positioned. 2 types of visible light curing machine, the power density of one of which was 400$mW/cm^2$ and the other was 900$mW/cm^2$, and one type of argon laser were used to cure the restorative composite and dual cured cement. For each group, 10 sample were assigned. The light curing tip was positioned over the composite overlay and light cured for 1min., 2min. or 3min with visible light curing machine or 15sec, 30 sec, 45sec, and 60 sec with argon laser. The Vickers hardnesses of upper and lower surface of Z100, Tetric Ceram, and 3 types of VL II cement were measured. When the 900 $mW/cm^2$ curing light was used, 2min. was needed for optimal curing of Z100 and Tetric Ceram. Variolink II did not be cured optimally even though the curing time was extended to 3min. When 400$mW/cm^2$ curing light was used, 3min. was necessary for Z100, whereas 3min. was not enough for Tetric Ceram. Variolink II was not cured optimally even though the curing time was extended to 3min. When argon laser was used, Z100, Tetric Ceram and Variolink II were not cured optimally in 60 seconds.

• Journal of Dental Rehabilitation and Applied Science
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• v.30 no.2
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• pp.112-120
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• 2014

Purpose: This study compared the shear bond strength of heat pressed and feldspathic porcelain to metal. Through thermocycling, the clinical aspect of heat pressed porcelain fused metal was estimated. Materials and Methods: 90 non-precious metal specimens were made ($4{\times}4{\times}8 mm$) and divided to three groups. All spicimens were treated and built-up with the porcelain ($4{\times}4{\times}3 mm$) by 2 different methods according to group: Group I: $Inspiration^{(R)}$, Group II: Ivoclar, IPS $Inline^{(R)}PoM$, Group III: GC Initial IQ-One $Body^{(R)}PoM$. The half of each group's specimens were thermocycled. All specimens' shear bond strength were measured by Instron universal testing machine. Exact measuring point was far 1 mm from porcelain/metal interface to the porcelain side. For the statistical analysis, 2-way ANOVA was used. Results: In no-thermocycling specimens, the shear bond strength showed no statistical significance between each group (P > 0.05). In comparison between nothermocycling and thermocycling specimens in each group, the shear bond strength was decreased according to thermocycling, but there was no statistical significance (P > 0.05). In thermocycling specimens, there was no statistical significance between each group (P > 0.05). Conclusion: In feldspathic porcelain and other two types heat pressed porcelain, there was no statistical difference in the shear bond strength of porcelain to metal. The heat pressed porcelain seems to be clinically useful for the aspect of the shear bond strength.