• Composites Research
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• v.33 no.2
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• pp.76-80
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• 2020

In this study, vacuum bag hot-press (V-HP) process can be used as an out-of-autoclave (OOA) process by improving the inefficient process of the autoclave forming method with excellent physical properties and surface quality. A carbon fiber composite was molded via V-HP process and analyzed the physical properties and microstructures between composites manufactured by autoclave (AC) process and hot-press process (HP). The tensile strength of the composite materials using the V-HP process was 320.6 MPa and the AC process samples found to be substantially close to the tensile strength of 335.3 MPa. As a result of confirming the surface quality of the composite material using SEM, it was confirmed that in the V-HP process, the removal state of pores due to volatile solvent in the resin was slightly lower than that of the AC process, but it had a considerably superior surface compared to the HP process.

• Design & Manufacturing
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• v.11 no.2
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• pp.15-19
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• 2017

Carbon fiber reinforced plastic (CFRP) is applied as structural material. CFRP is excellent in plane strength / stiffness and don't haves rust. Lightweight, rigid and robust at the same time as transportation material. Aluminum alloy and reinforcement material The application is increasing rapidly. In this study, the prototype of a semi - Monocoque structure frame, Longeron, Stringer, Skin of the aircraft, restraining the rigidity Clips of the aircraft was designated as the target product and the experiment was conducted. ln the experiment, (1) For CFRTP 3 points, data on heating, transfer, and cooling were measured using Thermo Couple, and optimum temperature required for flexible state was obtained. Heating was performed at a temperature 15% higher than the provided temperature. (2) By using a pneumatic press during molding, by dividing LH, center and RH according to the cooling time, thickness parameter of the target product due to the load is measured, and thickness control and time-deviations were analyzed and cross sections were observed with a low magnification microscope.

• Composites Research
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• v.36 no.5
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• pp.310-314
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• 2023

VaRTM(Vacuum assisted resin transfer molding) and VAP(Vacuum assisted process) processes are a type of RTM(Resin transfer molding) process, and are typical out-of-autoclave (OOA) processes that can manufacture large structures at low cost. In this paper, a resin filling test was conducted to compare the VaRTM and VAP processes, and the filling process and dimensional stability were compared. In addition, an analysis method to simulate the filling process was developed, and a dielectric sensor was used to detect the flow front of the resin, which was compared with the analysis results. From the resin filling test, the total filling time of the composite plate was measured to be 48 minutes for the VAP process and 145 minutes for the VaRTM process, and the filling time by the VAP process was reduced by about 67%. In addition, it was confirmed that the VAP process was superior to the VaRTM process in the thickness control ability and uniformity of the composite plate.

• Journal of KIISE:Software and Applications
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• v.30 no.3_4
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• pp.202-211
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• 2003

Abstract Formal definitions of syntax and semantics for the static and dynamic models in Object Oriented methods are already defined. But the behavior of interacting objects is not formalized. In this paper, we defined the common behavior of interacting objects in terms of process algebra using sequence diagram in UML and regularized properties of interacting objects. Based on the results, we can develop a formal specification by. using of the object interaction instead of the existence dependency suggested by M. Snoeck and G. Dedene[9].

• Magazine of the Korean Society of Agricultural Engineers
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• v.44 no.4
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• pp.75-84
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• 2002

The irrigation facilities are managed systematically and a facility is independent at the view of shape and function. The design of the irrigation facility is the formulated process with independent objectives. So its process is accordance to object-oriented concept. The design of irrigation facilities is classified into several steps. In these steps, the design data is made and the various problems are solved and consolidated with analysis and decision. In order to achieve our goal of constructing an efficient integrated design system, the results from the design should be able to be systematically connected and re-used. In the study, the design task of irrigation facility, the integrated design system for (IDSAF) is to be developed using the object-oriented methods, and then its applicability will be examined.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.6
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• pp.966-973
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• 2002

This Pager presents an object-oriented analysis and design for Remote Examination System on Internet. The UML is used for describing the process of analyzing and designing the system. The system is composed of the parts: Question Generation part that professors make questions, Question Answer part that students answer the questions. By object-oriented analysis and design, the system inherits the advantages of object-oriented methodology. All the results are retained on database on server-side. This system can be integrated with the Cyber-University System, and substituted for off-line paper-based tests or adopted to on-line poll applications on Internet.

• Composites Research
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• v.32 no.1
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• pp.45-49
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• 2019

Fiber reinforced composites fabricated by the resin film infusion (RFI) process, which is one of the outof-autoclave process, have the advantage of significantly reducing the processing cost in large structures while having excellent mechanical properties and uniform impregnation of the resin. In this study, we applied RFI carbon fiber composites to unmanned aerial vehicle structures to improve structural safety and achieve weight reduction. The tensile test results showed that the strength was 46% higher than that of generic T300 grade plain weave carbon fiber composites. As a result of the layup design and finite element analysis of the composite wing structure using the above material properties, the wing tip deflection is decreased by 31%, the structural safety factor is increased by 28% and the weight of the entire structure can be reduced by more than 10% compared to the reference model using glass fiber composite material.