• Journal of Biomedical Engineering Research
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• v.28 no.2
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• pp.280-286
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• 2007

The wearable sensor glove was developed using EDA sensors and conducting fabric. EDA(Electro-dermal Activity) signal is an electric response of human skin. There are SIL(Skin Impedance Level) and SIR(Skin Impedance Response) in EDA. SIL consists mostly of a DC component while SIR consists of an AC component. The relationship between drowsiness and the EDA signal is utilized. EDA sensors were made using a conducting fabric instead of AgCl electrodes, for a more suitable, more wearable device. The EDA signal acquisition module was made by connecting the EDA sensor gloves through conductive fabric lines. Also, the EDA signal acquisition module can be connected to a PC that shows the results of the EDA signal processing analysis and gives proper feedback to the user. This system can be used in various applications to detect drowsiness and prevent accidents from drowsiness for automobile drivers.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.7
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• pp.500-507
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• 2018

A three-channel radio frequency (RF) monopulse receiver using a data signal with a maximum transmission rate of 274 Mbps was designed. A monopulse receiver using a broadband communication signal was designed to operate in the Ku band, and it consists of a down-conversion module and a signal-processing module. To satisfy the performance of the proposed RF monopulse receiver, a signal-processing function less than the reception sensitivity for each transmission rate according to the adaptive transmission rate is required. To minimize signal reception and mutual frequency interference of various bandwidths, two RF filters were applied. To verify the satisfaction of system requirements, an AWR Corp. simulation tool was used.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2001.06a
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• pp.17-20
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• 2001

In this paper, we realized a transceiver system for short distance communication with a commercial RF module working in ISM band. Also we measured system performance by transmitting baseband data in a building and then we compared the demodulated data bits with stored data bits in a PC connected with demodulator. The RF module In the experiments works only in the bandwidth of 424MHz-429MHz. The signal level degrades as the distance between transmitter and receiver increases. We measured the signal level and bit error and present the measured results with various locations in the building. And it is concluded that the measured data may be used in the design of short distance network in a building.

• Proceedings of the IEEK Conference
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• 2002.06e
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• pp.55-58
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• 2002

This paper describes an RF module for 2.4GHz wireless audio/video transmission. The pre-processed baseband input signals are FM-modulated using a VCO and then transmitted through an antenna after RF filtering. The designed circuits are implemented using a Teflon board of which the size is 52mm${\times}$62mm. The measured maximum output signal levels are around -3dBm and the harmonics are less than -450dBc. The manufactured module consumes 130mA from a 8V supply.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.10
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• pp.223-227
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• 2014

This paper presents an improvement method for human body sensing module and management system, specifically focused on the human body detection module with ultrasonic sensors to detect the usage of toilets and the management system to control the state of the toilets of the entire building. The proposed human body sensing module consists of the detection sensor to detect the movement of human body and the contact sensor to detect the position in a certain distance. The management system is configured of the control unit to process the signal transmitted from sensors, opening and closing valves according to the sensing signal, and the short range wireless communication unit to save the operational status data as well as transmit the data at regular intervals.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.06a
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• pp.515-520
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• 1998

In this paper, we propose a new fault tolerant architecture for high availability systems, where for module internal operations both processor modules perform the same tasks at the same time independently of each other while for module external operations both processor modules act actively. That is, operations of synchronization between dual processor modules except clock synchronization are requested only when module external operations are executed. The architecture can not only improve system availability by reducing system reintegration time but also reduce performance degradation problem due to frequent synchronization between dual processor modules. The clock unit consists of a clock generator and a clock synchronization circuit. This supplies a stable clock signal under clock unit disorder of any processor module or rapid clock signal variation. And this architecture achieves system availability and data credibility by designing as symmetrical form.

• Journal of Institute of Control, Robotics and Systems
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• v.12 no.6
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• pp.539-546
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• 2006

The Air Quality Sensor(AQS), located near the fresh air inlet, serves to reduce the amount of pollution entering the vehicle cabin through the HVAC(heating, ventilating, and air conditioning) system by sending a signal to close the fresh air inlet door/ventilation flap when the vehicle enters a high pollution area. The sensor module which includes two independent sensing elements for responding to diesel and gasoline exhaust gases, and temperature sensor and humidity sensor was designed for intelligent AQS in automobile. With this sensor module, AVR microcontroller was designed with back propagation neural network to a powerful gas/vapor pattern recognition when the motor vehicles pass a pollution area. Momentum back propagation algorithm was used in this study instead of normal backpropagation to reduce the teaming time of neural network. The signal from neural network was modified to control the inlet of automobile and display the result or alarm the situation in this study. One chip microcontroller, ATmega 128L(ATmega Ltd., USA) was used for the control and display. And our developed system can intelligently reduce the malfunction of AQS from the dampness of air or dense fog with the backpropagation neural network and the input sensor module with four sensing elements such as reducing gas sensing element, oxidizing gas sensing element, temperature sensing element and humidity sensing element.

• Journal of Communications and Networks
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• v.18 no.2
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• pp.201-209
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• 2016

In wireless sensor networks (WSNs) duty cycling has been an imperative choice to reduce idle listening but it introduces sleep delay. Thus, the conventional WSN medium access control protocols are bound by the energy-latency tradeoff. To break through the tradeoff, we propose a radio wave sensor called radio frequency (RF) wakeup sensor that is dedicated to sense the presence of a RF signal. The distinctive feature of our design is that the RF wakeup sensor can provide the same sensitivity but with two orders of magnitude less energy than the underlying RF module. With RF wakeup sensor a sensor node no longer requires duty cycling. Instead, it can maintain a sleep state until its RF wakeup sensor detects a communication signal. According to our analysis, the response time of the RF wakeup sensor is much shorter than the minimum transmission time of a typical communication module. Therefore, we apply duty cycling to the RF wakeup sensor to further reduce the energy consumption without performance degradation. We evaluate the circuital characteristics of our RF wakeup sensor design by using Advanced Design System 2009 simulator. The results show that RF wakeup sensor allows a sensor node to completely turn off their communication module by performing the around-the-clock carrier sensing while it consumes only 0.07% energy of an idle communication module.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1201-1206
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• 2003

A measurement device for gas flow rate using hot-wire module is developed for the utilization in low-accuracy industrial applications. The module has three wires of measuring and heating, and a bridge circuit is installed to detect electric current through the wire in the module. An amplification of the signal and conversion to digital output are conducted for the online measurement with a personal computer. In addition, temperature distribution in the module is numerically analyzed to examine the measured outcome from the module experiment. The flow rate of air and carbon dioxide gas is separately measured for the performance examination of the device. The experimental relation of measurement and flow agrees with the prediction from the numerical analysis. The outcome of the performance test indicates that the accuracy and reproducibility of the module is satisfactory for the purpose of industrial applications.

• Proceedings of the KIPE Conference
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• 2013.11a
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• pp.79-80
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• 2013

MMC(Modular Multilevel Converter)는 여러 개의 Power Module을 직렬로 연결하여 정현파에 가까운 고전압의 파형을 얻을 수 있는 토폴로지로 대용량 전력변환 분야의 요구를 만족하면서 전력 품질을 향상시킬 수 있어 근래에 상당히 주목받고 있다. 당사에서는 5Mvar급 STATCOM(STATic synchronous COMpensator)을 MMC 형태로 제작하였다. 제작된 5Mvar급 STATCOM은 한 상당 12대의 Power Module로 구성하여 25-Level로 제작되었다. 제어시스템은 DSP(Digital Signal Processor)를 이용하였으며, 하나의 Main Controller와 다수의 Cell Controller, FPGA 보드 등으로 구성되어 있다. Controller 간의 상호 정보를 교환하기 위해 CAN 통신을 이용하였고, Power Module의 스위칭을 위한 보드는 각각에 연결되어 있으며, Cell Controller보드와는 절연을 위해 광신호로 연결하였다. 본 논문에서는 MMC 시스템의 제어기간 CAN 통신인터페이스와 Power Module의 PWM 동기화에 대해 설명을 하였다.