• International Journal of Aeronautical and Space Sciences
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• v.13 no.1
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• pp.117-125
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• 2012

This paper presented the design of SRPS, ground function test, and the deployment test on a high speed taxi of KC-100 airplane. KAI has developed a spin recovery system in collaboration with Airborne Systems for KC-100 general aviation airplane. Spin mode analysis, rotary balance and forced oscillation tests were performed to obtain the rotational, dynamic derivatives in the preliminary design phase. Prior to the detailed design process of SRPS, approximations for initial estimation of design parameters- fineness ratio, parachute porosity, parachute canopy filling time, and deployment method- were considered. They were done based on the analytical disciplines such as aerodynamics, structures, and stability & control. SRPS consists of parachute, tractor rocket assembly for deployment, attach release mechanism (ARM) and cockpit control system. Before the installation of SRPS in KC-100 airplane, all the control functions of this system were demonstrated by using SBTB(System Breakout Test Box) in the laboratory. SBTB was used to confirm if it can detect faults, and simulate the firing of pyrotechnic devices that control the deployment and jettison of SRPS. Once confirmed normal operation of SRPS, deployment and jettison of parachute on the high speed taxiing were performed.

• Journal of the Korean Society of Propulsion Engineers
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• v.22 no.4
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• pp.108-116
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• 2018

A firing test of the 75 tonf-class liquid rocket engine to be used as the first and second stage engines of the KSLV-II was carried out at the rocket engine test facility(RETF). Since this engine uses liquid oxygen as the oxidizer, which is a cryogenic fluid, it is essential that the chill down of the supply pipe line and engine proceed for the firing test; thus, the given inlet requirements must be met. Moreover, it is important to understand the chill down characteristics of the facility and the engine and the amount of liquid oxygen consumed in the chill down process for efficient test operation in the future. In this paper, chill down characteristics of the supply pipe and the engine were evaluated through the investigation of the chill down process of the 75 tonf-class liquid rocket engine at each stage before and after run tank pressurization. In addition, the amount of liquid oxygen consumed was also evaluated.

• Journal of the Korean Society of Propulsion Engineers
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• v.25 no.3
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• pp.89-100
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• 2021

This paper deals with the construction of a combustion test facility and preliminary tests for hot-firing tests of a methane engine. First, the combustion test facility for a 1 kN-class thrust chamber using liquid oxygen/gas methane as propellants was designed and built. Before hot-firing tests, the cold-flow tests of each propellant line and the ignition tests of torch igniter/afterburner were performed to verify propellant supply stability of the combustion test facility, operation of the control and measurement system, and successful ignition. Finally, a preliminary hot-firing test was conducted to measure the combustion efficiency, heat flux, and combustion stability of a thrust chamber prototype. The constructed combustion test facility will be helpfully used for basic research and development of methane engine thrust chambers.

• Journal of The Korean Society of Integrative Medicine
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• v.10 no.2
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• pp.85-93
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• 2022

Purpose : This study aims to examine the effect of ego resilience and social support on test anxiety for university students majoring in occupational therapy and use the results as foundational data for program development that can reduce test anxiety. Methods : The study's subjects were 173 university students who understood the study's purpose and consented to participate in the study from March 7 to 25 in 2022. These students were in their second, third, and fourth years, majoring in occupational therapy at a four-year B university in A Metropolitan City and a three-year E College in D-gun C Province. Among them, those with missing data or indicated extreme values were excluded, and data from the final 168 students were studied. Results : The averages of test anxiety, ego resilience, and social support of university students majoring in occupational therapy were 3.06, 3.41, and 3.81, respectively. The factor that affected test anxiety was investigated. It was the school year in which the test anxiety of fourth-year students was significantly higher than that of second-year students. In addition, a positive attitude, which was one of the sub-factors of ego resilience, and support from friends and family, which were the sub-factors of social support, had a negative impact on test anxiety. Conclusion : The results of this study are as follows: First, it is necessary to conduct a study to verify the level of test anxiety of university students majoring in occupational therapy and the factors influencing them. Second, the operation and consultation of non-curricular programs that improve the ego resilience of university students should be conducted in universities and departments. Third, a measure to recognize support from surrounding environment and to ask for help from people around them should be required for university students majoring in occupational therapy.

• Journal of Korean Clinical Health Science
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• v.10 no.1
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• pp.1543-1552
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• 2022

Purpose: It is intended to investigate the satisfaction of dental hygiene students with non-face-to-face online classes and use them as basic data for successful lecture design and operation. Methods: The data collected in this study were analyzed using the lBM SPSS Statistics 21 program. The general characteristics of the study subjects were frequency analysis, non-face-to-face online class satisfaction, and test satisfaction were frequency analysis and technical statistics. Through the independent sample T test, a t-test was conducted to find out whether there was an average difference in online class and test satisfaction according to grade. Results: The advantages of non-face-to-face online classes were that repetitive learning was possible (57.7%), the disadvantage was that there was a lack of real-time communication (74.9%), and the most efficient teaching method was a mixed form of online and face-to-face classes (64.9%). The satisfaction level of online classes was 2.69 points for 'self-directed learning habits,' which was the highest compared to the overall average of 2.55 points, and 2.09 points for 'difficulty in interaction between instructors and learners in online classes.'Non-face-to-face test satisfaction was 2.68 points for 'short test time gives fairness to test results,' higher than the overall average of 2.45 points, and 2.07 points for 'no difficulty accessing the test.'In terms of satisfaction with the non-face-to-face test according to the grade, it was found that the third grade showed a more negative attitude than the second grade in terms of sexual fairness (p<0.05). Conclusions: Through the above results, non-face-to-face online classes require various content development and some mixed classes considering the level of students, and instructors' efforts to improve the quality of classes for interaction between instructors and learners are needed.

• Aerospace Engineering and Technology
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• v.4 no.2
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• pp.163-170
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• 2005

According to the KSLV program of KARI, it is planed to develop various launch vehicle and satellite 10 years hereafter. Large-scale test facilities, such as ReTF and PTA-II, are needed to fulfill this launch vehicle/satellite development project. The authors intend to arrange and describe various indexes that are needed in test facility design, construction and operation process. This technical paper is describing model analysis of damage prediction of accident in KSLV Integrated Propulsion System Test Facility based on propellant storage quantity and layout. In addition, the result can be used to produce safer design of test facility.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.4C
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• pp.207-214
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• 2005

In the indoor wireless communication, it is considered the indoor wireless system architecture of single input multiple output (SIMO) that used with multiple antenna in order to cope with the indoor fading characteristic due to severe angler spread. We propose the mean steering vector technique as a method to enhance the system Performance, implement the test bed system composed of a PC and the algorithms of the wireless system, and analysis the performance of those algorithms. In addition, the overall operation scenario, overall architecture, and the execution time of the algorithms, of the test bed for the indoor wireless system are presented.

• Journal of the Korea Institute of Military Science and Technology
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• v.23 no.5
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• pp.444-451
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• 2020

This study was conducted to develop the hydraulic brake assembly for MUAV(Medium-altitude Unmanned Aerial Vehicle). The brake assembly has the self-gap adjuster which performs to maintain a constant gap between the piston and the disk, even if the friction pad wore down. The function of adjuster helps to keep the brake-reaction speed constant and prevent the unnecessary abrasion of the wear pad during the life of the brake assembly. The development of the aircraft hydraulic brake assembly with the self-gap-adjuster in this paper is the first ever in South Korea. The concept of the mechanism was defined and the formula which is necessary to calculate the friction force was set up in the paper. The tester was invented for the functional test and the proper operation of the self-gap-adjuster was confirmed through the test. Dynamo tests and flight tests were also carried out to verify the braking performance of the brake assembly.

• Journal of Korean Society of Water and Wastewater
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• v.28 no.2
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• pp.225-233
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• 2014

This paper presents a Computational Fluid Dynamics(CFD) based simulation and experimental tracer test of flow pattern and turbulent energy dissipation inside a serpentine flocculation basin with continuous operation. Research focused on the evaluation of a specific flow pattern on the hydraulic behavior on the flocculation basin. From the results of CFD simulation and actual tracer test, both results were in good accordance with each other. Also, each Morill index were calculated as 1.5 from CFD simulation and 1.7 from actual tracer test, respectively. Especially, turbulence energy was dissipated relatively higher in the vicinity of inlet to the flocculation basin than other region. The differences between the CFD simulation and actual tracer test were 1.4 min in $T_{50}$, and 1.3 min in $T_p$, respectively.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1061_1061
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• 2009

Running low of fossil fuel energy forces the industry to find a new way to overcome this energy crisis. One of the solutions is using the unlimited and everlasting energy sources like wind, sun, water, and so on. Especially, sun energy becomes the hottest issue in recent years because of its merit in installation, operation and abundant material source of silicon. In 2008, about 5.5GW photovoltaic (PV) system has been installed all around world. Many professional renewable energy organizations expect that the total PV system installation will be 30GW. To sustain the long-term stability of the PV system, several institutes perform the test based on IEC standards like IEC 61215 for silicon crystalline PV module and IEC 61646 for thin film PV module. Also in South Korea, Korea Institute of Energy Research (KIER) performs the certificate test according to IEC 61215 standards. In this paper, we want to summarize and inform the 3 years‘ test results of domestic and foreign PV modules. The specific and technical explanation will be shown in the following paper in detail.