• Journal of the Chungcheong Mathematical Society
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• v.32 no.1
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• pp.149-156
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• 2019

This paper present the global generalized cross validation as the appropriate choice of the regularization parameter in the preconditioned Gl-LSQR method in solving image deblurring problems. The regularization parameter, chosen from the global generalized cross validation, with preconditioned Gl-LSQR method can give better reconstructions of the true image than other parameters considered in this study.

• International Journal of Industrial Entomology and Biomaterials
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• v.31 no.2
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• pp.56-61
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• 2015

Rutin is an important bioflavonoid that is consumed in the daily diet. This study compared the functional components of rutin from various silkworm species using a gene database with those of rutin produced by silkworms selectively bred through cross-combinations. We made comparisons between the geographical origin and species of silkworm using a gene database and discovered that rutin activity was ranked in the following order by species, Chinese (C5)> miscellaneous varieties (Jamsaeng 1 Ho) >Japanese (Jam 115) > European (E58) >Korean (Sun 3 ho). However, rutin levels with respect to various genetic traits (blood color, silk color, and egg color) were consistent. In order to study rutin changes that occurred during the cross breeding of the silkworm gene, we bred cross-combinations utilizing Jam 115 and the 4051 silkworms. In conclusion, in order to provide information about the constituents of functional materials contained in silkworm powder, it is imperative that silkworm cross breeding occurs so that the database of functional materials extracted from silkworms will expand.

• Transactions of Materials Processing
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• v.22 no.7
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• pp.401-406
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• 2013

The use of roll-formed products increases every year due to its advantages, such as high production rates, reduced tooling cost and improved quality. However, till now, it is limited to part profiles with constant cross section. In recent years, the flexible roll forming process, which allows variable cross sections of profiles by adaptive roll stands, was developed. In this study, an attempt to optimize profile design for the flexible roll forming process was performed. An equation that predicts the longitudinal strain for part geometries with variable cross-sections was proposed. The relationship between geometrical parameters and the longitudinal strain was analyzed and investigations on the optimal profile design were performed. Experiments were conducted with a lab-scale roll forming machine to validate the proposed equation. The results show that the profile design method proposed in this study is feasible and parts with variable cross sections can be successfully fabricated with the flexible roll forming process.

• International Journal of Industrial Entomology and Biomaterials
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• v.29 no.2
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• pp.162-168
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• 2014

1-Deoxynojirimycin(1-DNJ or DNJ), a component in silkworm powder, prevents glucose from being absorbed into the bloodstream from the small intestine by inhibiting ${\alpha}$-glucosidase activity. This study compared the functional components of 1-DNJ from various silkworm species using a gene database with those of 1-DNJ produced by silkworms bred through cross-combinations. We utilized comparisons of geographical origins and species of silkworms using a gene database and discovered that 1-DNJ activity was ranked in the following order by species, Japanese (SK-1) > Chinese (C48) > European (Rock191). 1-DNJ constituted varying percentages of silkworm organs in the following order, blood > epithelial tissue > body fat > silk glands. With regard to sex, 1-DNJ, levels were higher in males than females. However, 1-DNJ levels with respect to various genetic traits (blood color, silk color, and egg color) were consistent. In order to study 1-DNJ changes that occurred during cross breeding of the silkworm gene, we bred cross-combinations utilizing SK-1 and C48 silkworms. In conclusion, in order to provide information about the constituents of functional materials contained in silkworm powder, it is imperative that silkworm cross breeding occurs so that the database of functional materials extracted from silkworms will expand.

• Korean Journal of Applied Biomechanics
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• v.29 no.1
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• pp.1-8
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• 2019

Objective: The purpose of this study was to confirm that the cross-country ski sprint course in PyeongChang, where the 2018 Winter Olympics course was to utilize wearable devices equipped with inertial measurement unit (IMU), global positioning system (GPS) and heart rates sensor. Method: For the data collection, two national level cross-country (XC) skiers performed classic technique on the entire sprint course. We analyzed cycle characteristics, range of motion on double poling (DP) technique, average velocity, and displacement of 3 points according to the terrain. Results: The absolute cycle time gradually decreased during starting, middle and finish sections. While the length of the DP increased and the heart rates tended to increase for men skier. In addition, the results indicated that range of motion of knee joint during starting and finish section decreased more than middle section. The errors of latitude and longitude data collected through GPS were within 3 m from 3 points. Conclusion: Through the first case study in Korea, which analyzed the location and condition of XC skiers in the entire sprint course in real time, confirmed that feedback was available in the field using various wearable sensors.

• Asian Journal of Innovation and Policy
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• v.8 no.1
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• pp.73-96
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• 2019

This study suggests a new approach for identifying core robot tech-nologies based on technological cross-impact. Specifically, the approach applies data mining techniques and multi-criteria decision-making methods to the co-classification information of registered patents on the robots. First, a cross-impact matrix is constructed with the confidence values by applying association rule mining (ARM) to the co-classification information of patents. Analytic network process (ANP) is applied to the co-classification frequency matrix for deriving weights of each robot technology. Then, a technique for order performance by similarity to ideal solution (TOPSIS) is employed to the derived cross-impact matrix and weights for identifying core robot technologies from the overall cross-impact perspective. It is expected that the proposed approach could help robot technology managers to formulate strategy and policy for technology planning of robot area.

• Journal of Energy Engineering
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• v.14 no.4 s.44
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• pp.259-267
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• 2005

In an attempt to elucidate combustion mechanism or premixed spray flame in detail, both the enlarged photographing, which was performed for spray cross-sectional images of premixed spray flame, and the cross-correlation PIV, which was performed for consecutive time-series images to obtain instantaneous two dimensional flow field, were applied. This study indicated that CW laser as well as pulse laser could be applied for PIV. Furthermore, the results of cross-correlation PIV, which was self-made PIV program, was shown in good agreement with those of PDA. Therefore, it was verified that cross-correlation PIV using CW laser in this study could be effectively used for observing structure of premixed spray flame.

• Korea Trade Review
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• v.46 no.6
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• pp.211-224
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• 2021

Based on the perspective of international trade and cross-border e-commerce development, this paper explores the impact of cross-border e-commerce on international trade. This paper first describes the current situation of China's cross-border e-commerce and proposes a theoretical model of the influence of China's cross-border e-commerce on its international trade based on the research and summary of a large number of relevant documents. This paper establishes an extended gravity model based on the proposed theoretical model. Relevant data of 13 trading partner countries were used as sample data, and OLS regression analysis and heterogeneity analysis were conducted on gravity model by using Eviews 11.0. Then, in order to study the influence of each variable on import and export trade volume, import and export trade volume were respectively taken as explained variables and further studied by OLS regression analysis. To test the robustness of the model, the empirical analysis results show that cross-border e-commerce does promote the volume of China's international trade.

• 한국전산유체공학회:학술대회논문집
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• 2003.10a
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• pp.260-262
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• 2003

Cross-flow fans are widely used in various applications, due to their large capacity of mass flow and size compactness. The flow field of the cross-flow fan is, however, complex and has many design parameters. Thus, the general design guide has not been sufficiently established yet and the design strategies of cross-flow fans have been based on experiments. In the present study, the performance and their two-dimensional flow characteristics are numerically analyzed by using the STAR-CD(commercial computational fluid dynamics code). The simulation is done by varying the several design parameters such as the impeller blade shapes and the gap between the stabilizer and impeller. The computational results are compared with the experimental data at the fan outlet region. Finally some helpful guides for the optimum design of cross-flow fans are proposed.

• The KSFM Journal of Fluid Machinery
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• v.18 no.1
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• pp.11-19
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• 2015

Recently, the cross flow turbines attract more attention for their good performance over a large operating regime at off design point. This study employs a very low head cross flow turbine, which has open inlet duct and has barely been studied before, to investigate the performance of the cross flow turbine with air suction from the rear part of the runner. Unlike conventional cross flow turbines, a draft tube is attached to the outlet of runner to improve the turbine performance. Water level and pressure in the draft tube are monitored to investigate the influence of air suction. Torque at local blade passage of three parts of runner is examined in detail under the conditions of different air suction. Consequently, it is found that with proper air suction in the runner chamber, the water level in the draft tube gradually drops to Stage 2 of the runner and the efficiency of the turbine can be raised by 10%. Overall, the effect of air-layer on the performance of the turbine is considerable.