This focuses on the possibility of automatically performing CFD (computational fluid dynamics) analysis with hand-written sketches on paper(i.e. the easier way). The sketch is recognized and predicted as the target of the CFD analysis model by applying Deep Convolutional Neural Network suitable for classification of abstract sketch images. The sketch is only possible within the range of primitive geometric shapes in the field of CFD. The CFD analysis model needs to be prepared in advance in parametric format. This study shows that one-stop solution of CFD analysis is possible with the composition of the following procedures: 1) Sketch image recognition, 2) Sketch intention prediction for CFD analysis by using deep learning A.I., 3) Adaptation of reusable OpenFOAM case, 4) Interoperation with CFD application. Reusable OpenFOAM cases are coded in a parametric template format. Through this study, it was confirmed that the CFD analysis can be performed well by recognizing sketch written on paper. In this study, an elbow shape sample case at the prototype level was created and tested. As a result of the performance evaluation of the sketch recognition artificial neural network model, the accuracy of the sketch intention decision was relatively good at 87.5% (0.8750), and the loss was 37.3% (0.3729).

As environmental laws become stricter throughout the world, greater attention is being paid to carbon fiber composites for use as lightweight materials because of their excellent mechanical properties, such as higher specific stiffness and strength, compared with metal materials. However, because such materials are composed of carbon fiber and epoxy resin, a complex failure mechanism caused by crack initiation and propagation arises that depends on the fiber orientation and stacking sequence. Therefore, in this paper, a drop tower test and simulation were carried out to examine the collapse behavior of structural members of CFRP(Carbon Fiber Reinforced Plastics) with different stacking sequences. Simulations were performed for each case for various collapse modes to determine the impact collapse of the carbon composite using stress-based failure criteria.

In this study, the structural stability of a scientific payload installed on a KMSL cubesatellite for combustion experiment mission was investigated by a computational analysis. A scientific payload was preliminary design based on the design criteria of the pressure vessel, and linear structure analysis was performed using ANSYS V19.2 to verify the stability. As a result of this study, it was indicated that most of the maximum equivalent stress and strain occured in the center of the payload optical window. However, the payload designed with a minimum MOS of 2.94 has been shown to be structurally stable and robust under the given environmental conditions. Also the payload optical window can be damaged when the pressure difference between the inside and outside of the payload is 5 atmabs.

Natural halloysite kaolin contains many impurities, such as quartz phases, and varies in morphology and size during its formation in the earth. For it to be utilized as a new type of natural nano material, it is necessary to remove quartz impurities from the kaolin clays without affecting the morpholgy of its tubes. To remove quartz impurities from the kaolin by forming a well deflocculated aqueous slip without fracturing the morphology of the tubes, a slip of homogenized halloysite clay was recovered by adding polyvalent metallic cations and anionic polyelectrolyte flocculants simultaneously. This selectively flocculates the mixture of quartz and halloysite so that the halloysite particles form flows while the tubular halloysite remains in suspension. A dry separation process by grinding milling was adapted to compare the fine morphologies. Then a uniform size and tubular shape of the halloysite was obtained, and this could be used as a suitable container or a carrier to encapsulate nanomaterials.

Co(NO3)2 6H2O aqueous solution and sodium hydroxide were used to synthesize cobalt oxide (Co3O4) particles by precipitation method. The precipitated precursor was calcined at a temperature of 400 to 900°C to obtain cobalt oxide particles having a particle size of 100 to 500 nm. The crystallization process and morphology according to the calcination temperature were examined. The properties of the synthesized powder were evaluated using SEM, EDS and XRD. As a result of XRD diffraction and EDS analysis of the prepared powder, it was confirmed that Co3O4 is synthesized. As a result of heat treatment of the powder to 800℃, it was confirmed that crystal growth of cobalt oxide continues to occur.

Adsorption amounts of methylene blue on waste coffee powder increased with increasing pH and temperature of the solution. The maximum adsorption amounts of methylene blue on waste coffee powder was 0.67 mol/kg (298K, pH 10). Adsorption isotherms of methylene blue on wasted coffee powder was well fitted by the Langmuir equation. The estimated values for the free energy of adsorption (ΔG°) were -103.96, -116.36 and -120.93kJ/mol at 288, 298 and 308K, which indicated that a spontaneous process had occurred.

This study was designed to explore the antioxidant activities of water and ethanol extracts of Limonium tetragonum, Gleichenia japonica, and Sinomenium acutum leaves. Measurement of the total flavonoid and polyphenolic compounds showed that ethanol extracts had higher amounts than water extracts for all 3 plants. To estimate the antioxidant activities of leaf extracts with different solvents, DPPH and ABTS assays were carried out. In both the DPPH and ABTS assays for L. tetragonum, the antioxidant effect of water extract was slightly higher than that of ethanol extract at low concentration (12.5-50 μg/mL), but the opposite result was observed at 100 μg/mL. In the case of G. japonica, the ethanol extract showed higher antioxidant activity than the water extract over the entire range of concentrations in both the DPPH and ABTS assays. For the S. acutum extracts, the ethanol extract showed a greater antioxidant effect than the water extract over the entire concentration range by the ABTS method, but with the DPPH method the water extract showed a greater effect than the ethanol extract in the concentration range, except for the lowest concentration (12.5 μg/mL). HPLC was performed to analyze the polyphenolic compounds in the 3 ethanol extracts with testing for 17 polyphenolic compounds. Several polyphenolic compounds were detected with the highest amount found for hesperidin. These results imply the feasibility of the development of these leaf extracts as antioxidant agents.

The purpose of this paper is to analyze the effort distribution of a software design project and a software implementation project to determine the cost of the software design project and the cost of the software implementation project. To this end, we first analyzed the software engineering characteristics and established the basic concept of determining the effort distribution for the software design project and the software implementation project. Next, we analyzed the effort distribution data from the overseas literature survey, effort analysis data by ISBSG data, effort distribution data from the software project repository, and additional survey data comprehensively. Finally, we developed the final effort distribution for the software design project and the software implementation project.

In this study, a route-based group location registration (RGR) scheme is considered to reduce location registration and paging costs when there are many mobile stations (MSs) in a transportation system (TS) such as bus and train routes. In addition to adopting the existing group location tracking (GLT) scheme, the RGR scheme tries to minimize the total signaling cost by using the mobility characteristics of the TS whereby vehicles move along a specified route from the point of departure to the destination. In this study, we propose a 2-step paging (2SP) scheme based on an estimation of the location of the vehicles of a TS to reduce the paging cost of the RGR scheme. In this 2SP scheme, when an incoming call occurs, the first paging area is determined in accordance with an estimation of the location of the TS vehicle using the time from location registration to call occurrence. Since the moving speed of the TS vehicle is almost constant, the probability that the first paging will succeed is very high, which reduces the paging cost by roughly half. Numerical results show that the larger the route threshold K in the RGR scheme, the larger the reduction in total cost because of the 2SP effect. As a result, it can be seen that 2SP increases the optimal K, which minimizes the total cost compared with simultaneous paging. The results of this study can be used for mobility management research of mobile networks as well as for performance analysis of mobility management schemes.