• Design & Manufacturing
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• v.16 no.3
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• pp.22-27
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• 2022

The demand for new processing technology that can improve productivity is increasing in industries that require large-scale and various products. In response to this demand, a robot machining system with flexibility is required. Because of the low rigidity of the robot, the robot machining system has a large error during machining and is vulnerable to vibration generated during machining. Vibration generated during machining deteriorates machining quality and reduces the durability of the machine. To solve this problem, a stage for fixing the spindle during machining is required. In order to compensate for the robot's low rigidity, a system combining a piezoelectric actuator for generating a large force and a guide mechanism to actuate with a desired direction is required. Since the rigidity of flexible hinges varies depending on the structure, it is important to optimal design the flexible hinge and high-rigidity system. The purpose of this research is to make analytic model and optimize a flexible hinge and to design a high rigidity stage. In this research, to design a flexible hinge stage, a concept design of system for high rigidity and flexure hinge modeling is carried out. Based on analytic modeling, the optimal design for the purpose of high rigidity is finished and the optimal design results is used to check the error between the modeling and actual simulation results.

• Journal of Engineering Education Research
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• v.15 no.5
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• pp.119-124
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• 2012

The influences of the basic academic skills to the scholastic achievement grades has been researched and we made a test of the basic academic skills(Korean language, mathematic, foreign language) to the students of engineering department in I college in Seoul and analyzed the correlation between the basic academic skills and the scholastic achievement grades. Results show that the scholastic achievement grades has a correlation(r=.456, p<0.01) to the average grade of the basic academic skill test. High level students of the scholastic achievement grades have a correlation(r=.292, p<0.01) to the mathematical department and the others have a correlation(r=.232, p<0.05 and r=.279, p<0.01) to the Korean linguistic department. The results of this study through multiple regression analysis indicate that the scholastic achievement has a relation on Korean language skill. As a result, It is recommendable that the mathematical basic academic skill programs are suggested to the high-level students of the scholastic achievement grades and the linguistic basic academic skill programs to the others. Also, the required basic linguistic subject is needed to the low-level students of the basic academic skills and in this paper, we propose the test and management system for the basic campus-life skills including the basic academic skills and the basic major skills.

• Journal of the Korean Society of Safety
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• v.25 no.3
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• pp.53-60
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• 2010

LPG(Liquefied Petroleum Gas) vehicles in metropolitan area are being applied to improve air quality and have been proven effective for the reduction of air pollutant. In addition, LPG demand is growing rapidly as an environmentally friendly energy source and its gas station is also increasing every year. Consequently, this study tries to find out the influence of flame caused by the VCE(Vapor Cloud Explosion) in filling station on the adjacent combustibles and people by simulating relevant quantity of TNT. In addition, the damage estimation was conducted by using API regulations. If the scale of the radiation heat is known by calculating the distance of flame influence from the explosion site, the damage from the site can be easily estimated. And the accident damage was estimated by applying the influence on the adjacent structures and people into the PROBIT model. According to the probit analyze, the spot which is 30m away from the flame has 100% of the damage probability by the first-degree burn, 99.2% of the damage probability by the second-degree burn and 93.4% of the death probability by the fire.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.1
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• pp.592-598
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• 2017

A method for estimating the optical characteristics of ceramic materials under high temperature conditions has been applied and evaluated. For that purpose, an interface system combined with a photo-spectrometer was made to keep the samples at the required high temperature. The transmittance of the samples was measured at various temperatures. The measured transmittance data was used to estimate the refractive index using an optical simulation model in conjunction with the Sellmeier equation. The Sellmeier equation parameters were selected by trial-and-error when the transmittance recalculated using the estimated refractive index was compared with the measured transmittance. Furthermore, the estimated refractive indices were checked by a comparison with the reference data at some typical wavelengths at room temperature.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.7
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• pp.2945-2950
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• 2011

As the step to improve fuel efficiency, there is the system to build up the eddy of combustion chamber at the suction line in order to increase the combustion efficiency. The models installed with no vortex generation system or with various shapes of the system are examined by fluid analysis. Vortex generation system is installed prior to the suction of combustion chamber. The wing of this system winds itself around the suction air and generates the vortex. This study investigates the flow of suction air and the pressure distribution of suction stroke by using the eddy generation system.

• Journal of the Semiconductor & Display Technology
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• v.23 no.2
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• pp.1-5
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• 2024

In the electronics industry, a lot of research and development is being conducted on electronic component supply, component alignment and insertion, and automation of soldering on the back side of the PCB for automatic PCB assembly. Additionally, as the use of electronic components increases in the automotive component field, there is a growing need to automate the alignment and insertion of components with leads such as transistors, coils, and fuses on PCB. In response to these demands, the types of PCB and parts used have been more various, and as this industrial trend, the quantity and placement of automation equipment that supplies, aligns, inserts, and solders components has become important in PCB manufacturing plants. It is also necessary to reduce the pre-setting time before using each automation equipment. In this study, we propose a method in which a vision system recognizes the type of component and simultaneously corrects alignment errors during the process of aligning and inserting various types of electronic components. The proposed method is effective in manufacturing various types of PCBs by minimizing the amount of automatic equipment inserted after alignment with the component supply device and omitting the preset process depending on the type of component supplied. Also the advantage of the proposed method is that the structure of the existing automatic insertion machine can be easily modified and utilized without major changes.

• Journal of Convergence for Information Technology
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• v.10 no.10
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• pp.183-195
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• 2020

In this study, the objective of this study is to verify the effects between lecturer's capability, education program, education service, and physical educational environment factors, and university students' interest in and attitude toward mathematics. A survey was conducted on 228 male and female students in science and engineering majors attending universities in the Pusan metropolitan area, and empirical analysis was conducted using the SPSS 26.0 program. The research results are as follows. First, among the characteristics of college mathematics maker classes, instructor competency (β=.349, t=6.380, p<.001), educational program (β=.361, t=5.650, p<.001), and physical educational environment (β=.196, t=3.281, p<.01) had a significant positive (+) effect on college students' interest in mathematics. Second, the factors of interest (β=.349, t=6.380, p<.001) in college mathematics maker classes were found to have a significant positive (+) effect on college students' attitudes toward mathematics. Third, among the characteristics of college mathematics maker classes, instructor competency (β=.340, t=6.365, p<.001), educational program (β=.352, t=5.559, p<.001), physical educational environment (β=.226, t=3.537, p<.01) was found to have a significant positive (+) effect on college students' attitudes toward mathematics. Through the results of this study, it was concluded that when the level of education program and teaching ability of the university mathematics maker class are high and the physical educational environment is excellent, it can have a positive effect not only on the university student's attitude towards mathematics but ultimately on the attitude of mathematics.

• Journal of Practical Engineering Education
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• v.12 no.1
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• pp.145-162
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• 2020

The dual system in Korea already plays an important role in quantitative terms in the Korean lifelong vocational competency development system. However, since most of the existing dual system performance management plans in Korea focus on qualification-linked dual system, research on the effective performance management of the four-year university-driven dual system is very insufficient. This paper presents multiple measures for developing a performance management system suitable for the university-driven dual system to achieve qualitative improvement of the contract departments of the dual colleges or universities. As an approach to the end, a performance evaluation system is established by developing the evaluation items and indicators for the dual colloeges' contract departments. Next, it analyzes the needs of various stakeholder groups such as field teachers of the involved companies, students in apprenticeship and OJT professors of KOREATECH through FGI's and polls to diagnose the current operational performance, especially the causes of high drpout rates of the contract departments. From these results, the paper presents firstly the development of measuring methods for the developed performance indicators of the evaluation system and then a systemic performance management system which is based on 'input-transformation-outcome-feedback' structure. In addition, some measures for improving the high dropout rate and performance are presented from the viewpoints of each stakeholder.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.8
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• pp.642-648
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• 2019

This paper presents a fast back-type transfer device for snack food processing that uses the inertia of transferred material. A conventional conveying system is a drive system that uses a belt conveyor and mechanical crank, which generate noise and vibration and cause environmental pollution. Vibration and noise are reduced in the proposed fast back feeding device by using a counterweight. The crank drive unit was replaced with a linear servomotor, and an equilibrium device was designed to balance the force due to acceleration. This makes it is possible to adjust the forward and backward speed and acceleration through PLC control. A vibration damper device offsets the vibration force of the periodic shock form. The main cause of the vibration was identified through vibration analysis, and reduction measures were established. We verified the effectiveness of the vibration by making a prototype and performing about 10 vibration tests. Because no mechanical transducer is needed, energy loss, noise, and vibration do not occur, and the operating speed is not limited.

• Journal of the Korean Society of Safety
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• v.22 no.4
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• pp.110-116
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• 2007

There have been 3E problems of energy, economy and environment since the earth has its history. Especially, as the industrial society is highly developing, human need in daily life has also changed drastically. With the introduction of 40 hour working week system, more households enjoy picnics on weekends. More gas accidents take place on Saturdays and on Sundays than any other days of week. Consequently, this study tries to find out the influence of flame caused by the explosion of butane canister on the adjacent combustibles and people by simulating relevant quantity of TNT. In addition, the damage estimation was conducted by using API regulations. If the scale of the radiation heat is known by calculating the distance of flame influence from the explosion site, the damage from the site can be easily estimated. And the accident damage was estimated by applying the influence on the adjacent structures and people into the PROBIT model. According to the pro bit analyze, the spot which is 50cm away from the flame has 97% of the damage probability by the first-degree burn, 8% of the damage probability by the second-degree burn and 4% of the death probability by the fire.