• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.11
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• pp.1617-1624
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• 2012

A DC power system has many loads with varied functions. Also, there may be large pulsed loads with short duty ratios which can affect the normal operation of other loads. In this paper, Voltage Bus Conditioner(VBC) without any current sensors is proposed to damp the bus voltage transients by parallel pulsed loads. The proposed control approach requires only one voltage sensor and carries out both the functions of damping the bus voltage transients and maintaining the level of energy stored. The proposed control technique has been implemented on a TMS320F2812 Digital Signal Processor(DSP). Simulated results by a Matlab Simulink and experimental results are presented which verify the control principles and demonstrate the practicalty of the approach.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.52 no.11
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• pp.657-661
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• 2003

In this paper, we designed a portable digital pressure algometer which not only can measure the pain level objectively and quantitatively, but also is able to do RF communication. This system consists of pressure sensor for pain measurement, analog signal analysis, digital hardware based on PIC16C73B, RF communication and display. To evaluate the performance of the developed system, we measured pressure threshold using commercial analog PA(Pressure Algometer) and the proposed system, and then evaluated the correlation and confidence. Using linear regression analysis, standard deviation of 0.1731 and R-square value of 99.3% were obtained. In conclusion, the above results showed good performance and its usability in measuring the pain clinically.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.14 no.9 s.90
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• pp.819-826
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• 2004

A multi-step optimum strategy for the selection of the locations and directions of strain gauges is proposed in this paper to capture at best the modal response of blade in a series of modes on fan blades. It is consist of three steps including two pass reduction step, genetic algorithm and fine optimization to find the locations-directions of strain gauges. The optimization is based upon the maximum signal-to-noise ratio(SNR) of measured strain values with respect to the inherent system measurement noise, the mispositioning of the gauge in location and gauge failure. Optimal gauge positions for a fan blade is analyzed to prove the effectiveness of the multi-step optimum methodology and to investigate the effects of the considering parameters such as the mispositioning level, the probability of gauge failure, and the number of gauges on the optimal strain gauge position.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.1
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• pp.165-170
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• 2017

This paper presents an event-triggered model predictive controller for adaptive cruise control system with sampled and quantized-data. Unlike existing works, a longitudinal continuous-time model is used for the predictive control of the system. To efficiently utilize network resources, event-trigger scheme is employed, which allows limited sensor and actuator signal satisfying the condition that the measurement of errors is over the ratio of a trigger level. The proposed control gain is obtained by solving a convex problem satisfying several linear matrix inequalities at every sampling times. Simulation results are given to show the effectiveness of the proposed design method.

• Proceedings of the KSRS Conference
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• 2002.10a
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• pp.89-94
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• 2002

Recently, DARI implemented the receiving and processing system for MODIS sensor data from NASA EOS satellites (TERRA and AQUA). This paper shows the development strategy considered, system requirement derived, system design, characteristic and test results of processing system. System operation concept and sample image are also provided. Implemented system was proven to be fully operational through lots of pass operations activities from RF signal reception to level-1 processing.

• Korean Journal of Remote Sensing
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• v.19 no.1
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• pp.37-42
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• 2003

Recently, KARI implemented the receiving and processing system for MODIS sensor data from NASA EOS satellites (TERRA and AQUA). This paper shows the development strategy considered, system requirement derived, system design, characteristic and test results of processing system. System operation concept and sample image are also provided. Implemented system was proven to be fully operational through lots of pass operations activities from RF signal reception to level-1 processing.

• Journal of IKEEE
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• v.16 no.3
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• pp.274-282
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• 2012

In this paper, we propose the design of lighting control algorithm for intelligent LED lighting system. The proposed lighting control algorithm transmitted to MCU through a data bus the environmental information detected from respectively sensor node. The MCU control software was designed to determine the level maintained to depending on the set control method by comparing the results that calculated the dimming level using a signal value. Also, it was designed to be lighting by cross-performed periodically the rotation and reverse method by created fully symmetrical pattern using the control algorithm to LED lighting device. In this paper, the proposed lighting control algorithm improved the reliability of the data sent by designed the system that can be controlled lighting to stable, and it was maintained the event delivery ratio of 91%. Also, the lighting device was decreased the luminous intensity of 32%, the power consumption of 49%, and heat generation of 32%. As a result, it were could be improved the energy efficiency that the life-cycle of LED has been increased 50%.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.2
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• pp.1250-1264
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• 2017

This paper presents the architecture design, implement, experimental validation of a bistatic backscatter wireless communication system in Wi-Fi network. The operating principle is to communicate a tag's data by detecting the power level of the power modulated Wi-Fi packets to be reflected or absorbed by backscatter tag, in interconnecting with Wi-Fi device and Wi-Fi AP. This system is able to provide the identification and sensor data of tag on the internet connectivity without requiring extra device for reading data, because this uses an existing Wi-Fi AP infrastructure. The backscatter tag consists of Wi-Fi energy harvesting part and a backscatter transmitter/a power-detecting receiver part. This tag can operate by harvesting and generating energy from Wi-Fi signal power. Wi-Fi device decodes information of the tag data by recognizing the power level of the backscattered Wi-Fi packets. Wi-Fi device receives the backscattered Wi-Fi packets and generates the tag's data pattern in the time-series of channel state information (CSI) values. We believe that this system can be achieved wireless connectivity for ultra- low-power IoT and wearable device.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.15 no.5
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• pp.116-124
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• 2016

This paper proposes a medium access control protocol for collision detection and resolution when a large number of sensor nodes transmits data in vehicle. The proposed protocol selects a random collision detection (CD) slot after data transmission, suspends its transmission and senses the channel to check whether a collision occurs by the detection of both energy level and jam signal. The proposed scheme uses multiple CD phases and in each CD phase, colliding stations are filtered and only surviving stations compete again in the next CD phase; thus, the collision resolution probability significantly increases. Simulation results show that the proposed protocol using the multiple CD phases has significantly better throughput than the conventional protocol. In addition, according to the number of CD phases and the number of CD slots per phase, the throughput aspect of the proposed scheme is investigated and the optimal parameters are derived.

• Journal of Industrial Technology
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• v.40 no.1
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• pp.13-18
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• 2020

Lithium-ion batteries have a small volume, light weight and high energy density, maximizing the utilization of mobile devices. It is widely used for various purposes such as electric bicycles and scooters (e-Mobility), mass energy storage (ESS), and electric and hybrid vehicles. To date, lithium-ion batteries have grown to focus on increasing energy density and reducing production costs in line with the required capacity. However, the research and development level of lithium-ion batteries seems to have reached the limit in terms of energy density. In addition, the charging time is an important factor for using lithium-ion batteries. Therefore, it was urgent to develop a high-speed charger to shorten the charging time. In this thesis, a discharger was fabricated to evaluate the capacity and characteristics of Li-ion battery pack which can be used for e-mobility. To achieve this, a smart discharger is designed with a combination of active load, current sensor, and temperature sensor. To carry out this thesis, an active load switching using sensor control circuit, signal processing circuit, and FET was designed and manufactured as hardware with the characteristics of active discharger. And as software for controlling the hardware of the active discharger, a Raspberry Pi control device and a touch screen program were designed. The developed discharger is designed to change the 600W capacity battery in the form of active load.