• Journal of the Korean Society for Precision Engineering
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• v.18 no.2
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• pp.54-62
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• 2001

This paper describes a new method for measuring the changes in specific surface asperities arising from processes such as finishing, coating, wear and corrosion. In repetitive measurements, relocation device gives the same position and orientation so that specific profile can be obtained. A low-cost relocation device is designed and its performance is assessed. The error in relocation process is compensated by statistic compensation algorithm. And, a removing process of cusp by grinding is observed by the proposed method.

• Journal of Sensor Science and Technology
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• v.19 no.3
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• pp.230-237
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• 2010

In sensor signal conditioning and processing, offset and drift characteristics of an operational amplifier are an important factor when the amplifier is used for a precise sensor signal amplifier. In order to use it in high accuracy, an expensive trimming or a complex compensation circuit is required. This paper presents the improved sensor signal conditioning and processing device for ubiquitous sensor network(USN) application or general purpose by developing a hardware of the circuit for reducing the offset voltage and drift characteristics, and a software for its control and sensor signal processing. We realize better offset voltage and drift characteristics of the signal conditioning circuit using low cost operational amplifiers. The experimental results show that this technique is effective in improving the performance of the sensor signal processing device.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.16 no.2
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• pp.119-124
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• 2016

According to the expansion of smartphone penetration and development of wearable device, personal context information can be easily collected. To use this information, the context aware recommender system has been actively studied. The key issue in this field is how to deal with the context information, as users are influenced by different contexts while rating items. But measuring the similarity among contexts is not a trivial task. To solve this problem, we propose context aware post-filtering to apply the context compensation. To be specific, we calculate the compensation for different context information by measuring their average. After reflecting the compensation of the rating data, the mechanism recommends the items to the user. Based on the item recommendation list, we recover the rating score considering the context information. To verify the effectiveness of the proposed method, we use the real movie rating dataset. Experimental evaluation shows that our proposed method outperforms several state-of-the-art approaches.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.4
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• pp.563-570
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• 1990

A silicon pressure sensor made of a full bridge of diffused resistors was designed and fabricated using semiconductor integrated circuit process. Thin diaphragms with 30\ulcorner thickness were obtained using anisotropic wet chemical etching technique. Our device showed strong temperature dependence. Compensation networks are used to compensate for the temperature dependence of the pressure sensor. The bridge supply voltage having positive temperature coefficient by compensation networks was utilized against the negative temperature coefficient of bridge output voltage. The sensitivity fluctuation of pressure sensor before temperature compensation was -1700 ppm/\ulcorner, while it reduced to -710ppm\ulcorner with temperature compensation. Our result shows that the we could develop accurate and reliable pressure sensor over a wide temperature range(-20\ulcorner~50\ulcorner).

• IEMEK Journal of Embedded Systems and Applications
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• v.18 no.5
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• pp.209-215
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• 2023

This study proposes an AC servo motor control program structure and its implementation method to efficiently integrate 13 types of additional compensation algorithms into the basic FOC (field-oriented control) algorithm program. Various compensation algorithms are necessary to enhance the stability and performance of machine tools by compensating for interference from disturbances and vibrations. Each compensation algorithm is implemented as a separate, independent function and called from a switch-case statement in the ISR (interrupt service routine) of the PWM (pulse-width modulation) device. The advantages of this approach include facilitating not only debugging and testing but also reducing the possibility of errors during the program development phase. Thus, it is easy to add and activate each specific compensation algorithm for the program update during the program operation phase. The implemented motor control program was experimented with a single-axis feed shaft testbed driven by a commercial AC servo motor control drive board and a 750 Watts SPMSM (surface-mounted permanent magnet synchronous motor), and the results verified its normal operation and performance improvement.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.11
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• pp.2729-2735
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• 2013

Safety and security system have been internationally enhanced in a field of shipping logistics. Accordingly, techniques for safety and security have been studied steadily. The need of portable radiation detection device is increasing by the search of the container is enhanced. In this paper, we propose to study on the application of the temperature compensation algorithm to the platform to improve the accuracy and the realization of portable radiation detection device based on Cortex-A9. Analog board deforms signal output from the sensor. And Cortex-A9 platform analyzes the signal received and displays the results. Additionally we use the temperature compensation algorithm and thereby we ca look the same results even if the temperature changes.

• Journal of Sensor Science and Technology
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• v.26 no.2
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• pp.141-147
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• 2017

A pressure sensor in pulse measurement system is a core component for precisely measuring the pulse waveform of radial artery. A pulse sensor signal that measures the pulse wave in contact with the skin is affected by the temperature difference between the ambient temperature and skin surface. In this study, we found experimentally that the signal changes of the pressure sensors and a temperature sensor were caused by the temperature of the wrist surface while the pressure sensor was contacted on the skin surface for measuring pulse wave. To observe the signal change of the pulse sensor caused by temperature increase on sensor surface, Peltier device that can be kept at a set temperature was used. As the temperature of Peltier device was kept at $35^{\circ}C$ (the maximum wrist temperature), the device was put on the pulse sensor surface. The temperature and pressure signals were obtained simultaneously from a temperature sensor and six pressure sensors embedded in the pulse sensor. As a result of signal analysis, the sensor pressure was decreased during temperature increase of pulse sensor surface. In addition, the signal difference ratio of pressure and temperature sensors with respect to thickness of cover layer in pulse sensor was increased exponentially. Therefore, the signal of pressure sensor was modified by the compensation equation derived by the temperature sensor signal. We suggested that the thickness of cover layer in pulse sensor should be designed considering the skin surface temperature.

• Plant Journal
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• v.17 no.2
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• pp.48-53
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• 2021

In the case of a 900 MW combined cycle power plant, most of the load on the site is a rotating device and is operated at a low power factor, and the power factor decrease increases the reactive power, which causes the efficiency of the device to be consumed and unnecessary unnecessary power consumption. This study intends to present the results by installing and operating a reactive power compensation device that absorbs and removes reactive power, which is a solution to this problem, on a 6.9 kV on-board bus. As a result of application of this system, first, it was confirmed that the power factor of the rotating machine was improved to 0.22 and the load power in the house was reduced by 1.4%, and the thermal efficiency of the generator was increased by 0.1% and the power generation power by 810 kW. Next, it was confirmed that the cost of construction and operation can be reduced in the future due to economic feasibility, with a decrease of 200 million won/year in electricity loss compared to 1.5 billion won in investment, an increase of 1 billion won/year in sales, and a one-year capital recovery period.

• Journal of Magnetics
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• v.16 no.1
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• pp.51-57
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• 2011

A power supply for magnetic-stimulation devices was designed via a control algorithm that involved a start current application based on a resonant converter. In this study, a new power supply for magnetic-stimulation devices was designed by controlling the pulse repetition frequency and pulse width. The power density could be controlled using the start-current-compensation and ZCS (zero-current switching) resonant converter. The results revealed a high-repetition-frequency, high-power magnetic-stimulation device. It was found that the stimulation coil current pulse width and that pulse repetition frequency could be controlled within the range of 200-450 ${\mu}S$ and 200-900 pps, respectively. The magnetic-stimulation device in this study consisted of a stimulation coil device and a power supply system. The maximum power of the stimulation coil from one discharge was 130 W, which was increased to 260 W using an additional reciprocating discharge. The output voltage was kept stable in a sinusoidal waveform regardless of the load fluctuations by forming voltage and current control using a deadbeat controller without increasing the current rating at the starting time. This paper describes this magnetic-stimulation device to which the start current was applied.

• Proceedings of the IEEK Conference
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• 2004.06b
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• pp.585-588
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• 2004

This paper describes design and verification of the motion estimation and compensation unit using full search algorithm. Video processor is the key device of video communication systems. Motion estimation is the key module of video processor. The technologies of motion estimation and compensation unit are the core technologies for wireless video telecommunications system, portable multimedia systems. In this design, Verilog simulator and logic synthesis tools are used for hardware design and verification. In this paper, motion estimation and compensation unit are designed using FPGA, coded in Verilog HDL, and simulated and verified using Xilinx FPGA.