• Journal of the Korean Vacuum Society
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• v.2 no.4
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• pp.515-519
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• 1993

Image processin software is developed to get spot intensity form the frame of a LEEd pattern obtained by using a CCD Camera and a frame grabber. Imporved algorithm for more reasonable background substraction is implemented in this software . I/V Charateristicsof some spots form Cu(001) suface are collected . These results are compared with those of Davis and Noonan and found to be consistent with the latter results. This software is also applied to meausre RHEEd spot intensity oscillatin, and gives clear oscillations very easily.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.1
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• pp.96-101
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• 2011

In this study, we have established the design techniques, with which we can design and evaluate performance of blades on a horizontal axis current turbine, by application of blade element momentum theory considering the blade tip's loss model, and finally developed the domestic software(MCT-blade V2.0). We have designed and evaluated performance of blades for the 2MW class by using of the software, and confirmed its calculation results from BEMT by comparing those results from commercial code of ANSYS FLUENT. In a state of rated velocity 2.5m/s, the mechanical power from BEMT is calculated as 2,121kW, which is considered to satisfy the electrical power, but the value from CFD is calculated as 1,901kW, which is considered a little deficient for the target output.

• Transactions of the KSME C: Technology and Education
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• v.3 no.2
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• pp.89-96
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• 2015

Based on multi-body dynamic software RecurDyn, this paper proposes a modified form of timing silent chain system combing with the existing problem that vibration and chain tension is too large, which is applied for complicated conditions in a V-type engine, such as high speed, variable loads. The analysis of chain drive meshing characteristics is completed. Using the multi-body dynamic soft-ware RecurDyn, the dynamics characteristics of the improved system is studied, including chain tension, transmission error, chain fluctuations, equivalent spring force in different operating conditions. The study results show that chain tension, transmission error, chain fluctuation and equivalent spring force are within the scope of permission, all of them can meet the design requirement. There-fore, the design of this system is reasonable and practicable. The research results will provide a basis for assessing timing silent chain system in a V-type engine and a theoretical reference for designing and optimizing the timing silent chain system.

• Journal of Industrial Technology
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• v.21 no.B
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• pp.281-286
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• 2001

In this study, product design and prototype manufacturing of a plastic water-pump pulley has been tried. The designed model is supposed to be made of 33 % glass reinforced resin of which the tensile strength is 180 MPa, and has 24 ribs on each side to increase its structural strength. Structural analysis under a static load of 300 kgf acting on both edges of the belt has been carried out using a commercial finite element code, MARC. The analysis result showed the maximum effective stress near a rib of designed model would be at most 35 MPa (less than 20% of the tensile strength), therefore, the plastic product would be sufficiently safe under that loading condition. On the basis of the structural analysis, a prototype of the designed model has been manufactured by using the fused deposition modelling (FDM) method which is one of the rapid prototyping (RP) methods, using ABS resin and support materials. The CAD data exported to the RP system in STL format was prepared by a commercial solid modeling software, SolidWorks. It has been proved that the plastic pulley can successfully replace the existing flow-formed steel product.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.6 no.1
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• pp.1-11
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• 2000

In optimum design of packaging container for bulk materials, minimum board area, compression performance and distribution efficiency must be considered. In this study, mathematical models for minimum board area (RMA), compression strength (CS) and maximum compression strength per unit board area (MCSA) of container as algorithm for optimum design of packaging conatiner for bulk materials were developed as follows : RMA=f(V,D), ${\alpha}_{RMA}=f(V,D)$, MCSA=f(V,D), and ${\alpha}_{MCSA}=f(V,D)$. In order to develop these models, compression test according to various dimensions of container and response surface analysis for minimum board area, compression strength, and maximum compression strength per unit board area of container were carried out. In developed models, volume and depth of container were principal independent variables. Through the verified results for these models, optimum design of packaging container on the design conditions and limit conditions was possible. These models might be used in developing optimum design software of packaging container for bulk materials.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.979-983
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• 2010

In case a set of railway vehicles moves on a rail track, the end of each car in which a coupler is installed produces a complex movement depending on the displacement of a rail track, bogie and a coupler. Especially, the movement of an end of cars is hugely affected by a radius of gyration and gradient of a rail track, vertical and lateral movement of bogie, and compression of coupler. In this thesis, I present a simulation technic for easy input and change of displacement of a rail track, bogie and a coupler as well as visualization of movement of the end of cars on a rail track using CATIA V5, CAD software.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.5
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• pp.888-908
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• 2011

The increasing demand from passengers in vehicles to improve safety, traffic efficiency, and comfort has lead to the growing interest of Wi-Fi based vehicle-to-infrastructure (V2I) communications. Although the V2I system provides fast and cost-effective Internet connectivity to vehicles via roadside Wi-Fi access points (APs), it suffers from frequent handoffs due to the high mobility of vehicles and the limited coverage of Wi-Fi APs. Recently, the Mobile AP (MAP) platform has emerged as a promising solution that overcomes the problem in the V2I systems. The main advantage is that MAPs may yield longer service duration to the nearby vehicles that have similar mobility patterns, yet they provide smaller link capacities than the roadside APs. In this paper, we present a new association control technique that harnesses available connection duration as well as achievable link bandwidth in high-speed vehicular network environments. We also analyze the tradeoff between two association metrics, namely, available connection duration and achievable link bandwidth. Extensive simulation studies based on real traces demonstrate that our scheme significantly outperforms the previous methods.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.16 no.2
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• pp.1-11
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• 2008

Increasing demand for improved reliability and survivability of mission-critical systems is driving the development of health monitoring and Automated Contingency Management (ACM) systems. An ACM system is expected to adapt autonomously to fault conditions with the goal of still achieving mission objectives by allowing some degradation in system performance within permissible limits. ACM performance depends on supporting technologies like sensors and anomaly detection, diagnostic/prognostic and reasoning algorithms. This paper presents the development of a generic prototype test bench software framework for developing and validating ACM systems for advanced propulsion systems called the Propulsion ACM (PACM) Test Bench. The architecture has been implemented for a Monopropellant Propulsion System (MPS) to demonstrate the validity of the approach. A Simulink model of the MPS has been developed along with a fault injection module. It has been shown that the ACM system is capable of mitigating the failures by searching for an optimal strategy. Furthermore, the concepts of Validation and Verification (V&V) of such systems are introduced with relevant examples.

• Journal of Electrical Engineering and Technology
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• v.13 no.2
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• pp.875-880
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• 2018

This paper proposes a novel combined compensation structure in the infrared receiver chip. For the infrared communication chip, the current-voltage (I-V) convert circuit is crucial and important. The circuit is composed by the transimpedance amplifier (TIA) and the combined compensation structures. The TIA converts the incited photons into photocurrent. In order to amplify the photocurrent and avoid the saturation, the TIA uses the combined compensation circuit. This novel compensation structure has the low frequency compensation and high frequency compensation circuit. The low frequency compensation circuit rejects the low frequency photocurrent in the ambient light preventing the saturation. The high frequency compensation circuit raises the high frequency input impedance preserving the sensitivity to the signal of interest. This circuit was implemented in a $0.6{\mu}m$ BiCMOS process. Simulation of the proposed circuit is carried out in the Cadence software, with the 3V power supply, it achieves a low frequency photocurrent rejection and the gain keeps 109dB ranging from 10nA to $300{\mu}A$. The test result fits the simulation and all the results exploit the validity of the circuit.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.59 no.3
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• pp.253-257
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• 2010

The frequency is an important operation parameter for the control, protection, and stability of a power system. The frequency as a key index of power quality can be indicative of system abnormal conditions and disturbances. Due to the sudden change in generation and loads or faults in power system, the frequency is supposed to deviate from its nominal value. It is essential that the frequency must be maintained very close to its nominal frequency. An accurate monitoring of the power frequency is essential to optimal operation and prevention for wide area blackout. As most conventional frequency estimation schemes are based on DFT filter, it has been pointed out that the gain error could cause defects when the frequency is deviated from nominal value. This paper presents an advanced frequency estimation technique using gain compensation to improve the performance of DFT filter based techniques. To evaluate performance of the proposed algorithm, the 765kV T/L system in Korea is simulated by EMTP-RV software. The proposed technique can reduce the gain error caused when the power system frequency deviates from nominal value.