• Journal of Aerospace System Engineering
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• v.18 no.3
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• pp.56-64
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• 2024

In this study, a drop impact tester was developed to comprehensively conduct basic testing and academic research on the drop impact characteristics of aerospace structures. A drop tester enables accurate assessment of the dynamic stresses and deformations that occur when an aircraft collides with the ground, thereby enabling the verification of important design factors, such as safety and mechanical strength. The drop tester consists of an electromagnet to attach and drop the test object, a crane to adjust the drop height of the test object, and a drop support structure for vertical drops. Numerical analysis of the drop test object for the test was performed, and basic tests were performed using the drop impact tester. Through the analysis and test results, the structural shape of the landing gear was analyzed, and the behavior of each part was evaluated.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.860-865
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• 2009

This thesis deals with application of Windows CE for Embedded System and the development methode of "Speed Gate Controller Tester" taking advantage of development program. We can improve reliability, stability and convenience of maintenance work as use of "Speed Gate Controller Tester" which was developed and applied "Embedded System" We can provide customers with more qualified service naturally because of the higher rate of operation which makes people use more pleasant and comfortable subway facility. And also it is possible to manage processor, time schedule and hardware resource as application of Embedded System and Windows CE. Embedded System applied OS Windows CE makes it possible to develop other various products, another application of equipment and tester. Thus this paper treats problems the moment developed and the present condition, development process, field application results.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1663-1667
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• 2003

This thesis is on tile development of LD(Laser Diode) chip tester and the control system based on graphical programming language(LabVIEW) to control the equipment. The LD chip tester is used to test the optic power and the optic spectrum of the LD Chip. The emitter size of LD chip and the diameter of the receiver(optic fiber) are very small. Therefore, in order to test each chip precisely, this tester needs high accuracy. However each motion part of the tester could not accomplish hish accuracy due to the limit of the mechanical performance. Hence. an image processing with machine vision was carried out in order to compensate for the error. and also a load test was carried out so as to reduce tile impact of load on chip while the probing motion device is working. The obtained results were within ${\pm}$5$\mu\textrm{m}$ error.

• Proceedings of the KIEE Conference
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• 2002.11c
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• pp.601-604
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• 2002

In this paper, the timing do-skew modeling for a high speed logic tester channels is developed. The time delay of each channel in a logic tester are different from other channels and it can produce timing error in a test. To get the best timing accuracy in the test with a logic tester, the timing skew must be compensated. The timing skew of channels is due to the difference of time delay of pin-electronics devices composing channels and length of metal line placed on PCB. The expected timing difference of channels can be calculated according to the specifications of pin electronics devices and strip line modeling of PCB. With the calculated delay time, the timing skew compensation circuit has been designed. With the timing skew compensation circuit, the timing calibration of a logic tester can be peformed easily and automatically without other time measuring instruments. The calibration method can then be directly applied to logic testers in mass production lines.

• Transactions of the Society of Information Storage Systems
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• v.8 no.1
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• pp.6-10
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• 2012

The tribological behavior of microsystems needs to be clearly understood in order to improve the reliability of precision components. For example, friction and wear phenomena pose serious problems in MEMS applications. As a first step to investigate the tribological behavior of such systems, an appropriate testing system must be acquired. In this work, a micro-wear tester based MEMS platform was designed. The main concern was to achieve a desirable range of horizontal displacement for the specimen holder and also to apply a normal force in the tens of ${\mu}N$ range. The structural analysis of the micro-wear tester showed that the proposed design satisfied these requirements while maintaining the structural integrity.

• Journal of the Semiconductor & Display Technology
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• v.3 no.2
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• pp.27-33
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• 2004

This paper is concerned with development of a micro tensile testing machine for optical functional materials such as single or poly crystal silicon and nickel film. Two micro tensile testers have been developed for various types of materials and dimensions. One of the testers is actuated by a PZT and the other is actuated by a servo motor for a precise displacement control. The specifications of PZT actuated micro tensile tester developed are as follows: the volumetric size of tester is desktop sized of 710$\times$200$\times$270 $mm^3$; the minimum load capacity and the load resolution in the load cell of 1N are 3 mN and 0.1 mN respectively; the full stroke and the stoke resolution of piezoelectric actuator are 1 mm and 10nm respectively. A special automatic specimen installing equipment is applied in order to prevent unexpected deformation and misalignment of specimens during handling of specimen for testing.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.49 no.11
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• pp.536-541
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• 2000

Digital protective relay in power system play a prominent part. Simulators for the relay test were introduced in early 1980's. A number of open loop designs have been developed and recently, several developments of real-time simulators have been reported. But they are very high cost. And then they are difficult to apply for relay testing in small business. This paper presents the structure of low cost and performance of a new pc based tester for digital protective relay testing. The proposed tester was simulated of off-line with fault transient signals obtained from EMTP.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.10
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• pp.1399-1411
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• 2012

The grid frequency is controlled cooperatively by the governor of the Turbine-Generator and the automatic generation controller(AGC) of the KPX(Korea Power Exchange). It is a basic requirement that the reliability of the governor is verified to enhance the power system stability but it is not easy to confirm the response characteristics of the governor because all generators are operated in the grid system that has the constant voltage and frequency. Therefore, it is necessary to study a new test method in order to examine the governor dynamic characteristic in the similar fault conditions. A study has shown that it is verified to simulate the turbine-generator power control system, the governor response characteristic under limited conditions and contribution of AGC with the gas turbine generator simulation model as well as demonstrate the dynamic response of the governor with the developed governor dynamic characteristic tester based on digital controller while the turbine-generator is connected to the grid system. This tester is constructed by the built-in functions of the turbine-generator main controller. In this treatise, the theoretical background, development method and the results of both simulations and demonstrations are described as another way to verify the turbine-generator governor dynamic characteristics.

• Journal of Power System Engineering
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• v.21 no.5
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• pp.29-34
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• 2017

Many household appliances, including vacuum cleaners, are being subjected to various of impact damages, and made of plastic. However, researches on the damage of appliances materials by repetitive impacts have been rarely conducted. the mechanical stress exerted upon impact-modified polycarbonate (PC) has a great influence not only on the quality of the product but also on the life span. The purpose of this research was to quantify the effects of repetitive impact on the polycarbonate. Second, it was to design the repetitive impact tester for controlling the impact energy. The mechanical properties of tensile strength, yielding stress and strain on the specimens subjected to cyclic impacts were discussed. Tensile strength was sharply declined at the beginning of the impact cycles, while the strain gradually decreased during impact cycles.

• International Journal of Safety
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• v.2 no.1
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• pp.34-38
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• 2003

The lower and upper flash points of the flammable binary system, butylacetate+2-propanol were measured by air blowing tester. The shape of the concentration-temperature region of flash depended on the components of the mixture in solution. The experimental data were compared with the values calculated by the reduced model under an ideal solution assumption and the flash point-prediction models based on Van Laar equation. Good qualitative agreement was obtained with these models. The prediction results of these models can thus be applied to incorporate inherently safer design for chemical process, such as the determination of the safe storage conditions for flammable solutions.