• Journal of Positioning, Navigation, and Timing
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• 제3권2호
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• pp.53-62
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• 2014

In the guided missile and unmanned vehicle system, the navigation system is one of the most important components. Recently, low-cost effective smart projectiles and guided bomb are being developed using MEMS based navigation system which has high-G, low-cost and small size. In this paper, locally developed MEMS based GPS/INS integrated navigation system will be introduced in comparison with the state of the art of MEMS based navigation system. And technical design and development method is described to satisfy the required performance of GPS receiver, MEMS inertial sensor assembly, navigation computer and software.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.113.1-113.1
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• 2014

Surface-enhanced Raman scattering (SERS) has long been projected as a powerful analytical technique for chemical and biological sensing applications. Pairing with portable Raman spectrometers makes the technique extremely appealing as real-time sensors for field application. However, the lack of reliable, uniform, low cost and ease-of-use SERS enhancement structures has prevented the wide adoption of this technique for general applications. We have discovered a novel hybrid structure based on the high-density and uniform arrays of gold nanofingers over a large surface area for SERS applications. The nanofingers are flexible and their tips can be brought together to trap molecules to mimic the biological system. We report here a rapid, simple, low-cost, and sensitive method of detecting trace level of food contaminants by using nanofinger chips based on portable SERS technique. We also present here the characterization of surface reaction of target molecules with our gold nanofinger substrates and the effect of nanofinger closing towards SERS performance. This new type of nano-structures can potentially revolutionize the medical and biologic research by providing a novel way to capture, localize, manipulate, and interrogate biological molecules with unprecedented capabilities.

• 대한전기학회논문지:전력기술부문A
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• 제54권4호
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• pp.159-164
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• 2005

Various compensators are installed into the power system to operate the system economically and stably by maximizing the availability of utilities and power transmission capability. Fixed Capacitor(FC), Mechanical Switched Capacitor(MSC), and FACTS(Flexible AC Transmission Systems) are used to regulate voltage and power flow of the system. When a disturbance occurs in the power system, the Fixed Capacitor operates dependently on the voltage of the power system and cannot change the amount of installation automatically. But compared to other equipment, the Fixed Capacitor is more economical due to its low cost. Since MSC can change the amount of installation according to the state of the power system, operates more effectively than the Fixed Capacitor. FACTS have fast dynamic performance for the transient condition, but the cost is high. Therefore, it is needed to develop an optimized installation planning for the reactive power compensators by considering their dynamic performance and cost. In this paper, an optimized compensator combination and the proposed scheme is proposed and it is applied to KEPCO system in order to show its capabilities.

• 한국정밀공학회지
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• 제17권12호
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• pp.61-67
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• 2000

In switched reluctance motor(SRM) drive, it is necessary to synchronize the stator phase excitation with the rotor position. Therefore the rotor position information is an essential. Usually optical encoders or resolvers are used to provide the rotor position information. These sensors are expensive and are not suitable for high speed operation. In general, the accuracy of the switching angle is dependent upon the resolution of the encoder and the sampling period of the microprocessor. But the region of high speed, switching angles are fluctuated back and forth from the preset values, which are cause by the sampling period of the microprocessor. Therefore, the low cost linear encoder suitable for the practical and stable SRM drive is proposed and the control algorithm to provide the switching signals using the simple digital logic circuit is also presented in this paper. It is verified from the experiments that the proposed encoder and logic controller can be a powerful candidate for the practical low cost SRM drive.

• 제어로봇시스템학회논문지
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• 제9권3호
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• pp.204-209
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• 2003

The line-of-sight stabilization system is an equipment which is loaded on a vehicle and stabilizes the direction of the line-of-sight of the vision sensor to obtain a not-swayed image in the existence of external disturbances. To obtain accurate Euler angles and angular velocities simultaneously we usually need a control system which uses high-price inertial sensors including Vertical Gyro(VG) or Rate Integrating Gyro(RIG). In this paper, we design and implement a control system of a gimbal, which is a line-of-sight stabilization system using a low-cost mixed algorithm of a rate gyro and an accelerometer instead of a VG and a RIG. In the experiment where we laid the implemented line-of-sight stabilization system on the rate table. we can see the stabilized performance to external disturbances.

• ETRI Journal
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• 제41권2호
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• pp.262-269
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• 2019

This paper introduces a low-cost, high-performance mmWave antenna array module at 77 GHz. Conventional waveguide transitions have been replaced by 3D CPW-microstrip transitions which are much simpler to realize. They are compatible with low-cost substrate fabrication processes, allowing easy integration of ICs in 3D multi-chip modules. An antenna array is designed and implemented using multilayer coupled-fed patch antenna technology. The proposed $16{\times}16$ array antenna has a fractional bandwidth of 8.4% (6.5 GHz) and a 23.6-dBi realized gain at 77 GHz.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2002년도 전력전자학술대회 논문집
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• pp.585-588
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• 2002

In this paper, the current controlled active poler filter(APF) with the performance of reducing harmonic and improving power factor is studied. It has high speed and good performance with low cost. The current controlled shunt APF is proposed, and the control part of APF is designed of SOC(System On Chip). So this system has low expense and good performance. In this study, the micro-controller which designed with VHDL. is applied to APF system. And the proposed technique in this paper demonstrates the excellent of the dedicated micro-controller. VHDL-based ASIC can simplify the process of development and has a competition in market because it reduces the consuming time for the design of IC(Integrated Circuit) in system level.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2009년도 하계학술발표대회 논문집
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• pp.623-628
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• 2009

Desiccant based air conditioning system offers a promising alternative to conventional one using vapour compression refrigeration for energy saving and greenhouse gas reduction. It is a heat driven cycle which has high potential for the use of low grade heat source such as the waste heat from the cogeneration plant or the solar thermal energy. In this study, the cooling performance of a desiccant cooling system incorporating a regenerative evaporative cooler was characterized in various operation conditions through numerical simulation. The cooling capacity and COP were evaluated at various outdoor conditions, regeneration temperatures, and supply flow rates. Based on the performance characteristics, the optimal control scheme was discussed to minimize the cooling cost at part load condition.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2017년도 추계학술대회
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• pp.47-48
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• 2017

This paper presents a low-cost portable lithium battery parameter measuring and estimating the solution. In this method, lithium battery characteristics are monitored during discharging and charging cycles. The battery profile is analyzed, and its key parameters are estimated by GNU Octave running on Raspberry Pi Zero, a mini computer. The proposed method can measure and estimate the battery parameters for SOC and DOD estimation with reasonable accuracy as well as portability features.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2000년도 춘계학술대회논문집 - 한국공작기계학회
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• pp.159-164
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• 2000

In SRM drive, The accuracy of the switching angles is dependent upon the resolution of the encoder and the sampling period of the microprocessor. As the speed increased, the amount of the switching angle deviation from the preset values is increased by the sampling period. Therefore, in this paper the low cost liner encoder for the practical and stable SRM drive is proposed and the control algorithm to provide the switching signals using the simple digital logic circuit is presented. and it is verified from the experiments that the proposed encoder and logic controller can be a powerful candidate for the practical low cost SRM drive.