• 한국전자통신학회논문지
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• 제11권4호
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• pp.403-410
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• 2016

금속으로 이루어진 물질의 경우에는 고유하며 명백한 공진 주파수를 가지고 있다. 이러한 성질을 이용하여, 공장에서 만들어진 제품의 품질 테스트를 실행할 수 있다. 해당 제품에 충격을 가하고 이로부터 발생되는 소리나 진동의 주파수를 고성능의 장비를 이용하여 측정하게 된다. 범용 컴퓨터나 DSP 기반의 단독 시스템들이 이를 위해서 사용되며 이러한 장비들은 들고 다니기에 크기가 너무 크고 구축비용이 많이 든다. 본 논문에서는 TI의 MSP430 계열의 MCU를 이용하여 개발된 시스템에 대하여 소개하고자 한다. 초저전력의 MSP430 MCU들은 큰 용량의 배터리가 필요 없으므로 매우 작은 크기의 주파수 분석기를 제작하는 것이 가능하게 한다. 제안된 시스템은 검사원이 쉽게 장비를 가지고 다닐 수 있어야 하고 정확도를 다소 희생하더라도 작은 개발비용이 요구되는 환경에 사용될 수 있을 것이다. 제안된 시스템은 론치패드를 이용하여 개발되었으며, 인위적이거나 자연스런 소리의 주파수를 매우 높은 정확도로 판별 할 수 있음을 확인할 수 있었다.

• 방송공학회논문지
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• 제12권1호
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• pp.53-60
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• 2007

Digital Broadcasting Satellite (DBS) 수신기는 실시간으로 위성으로부터 수신되는 방송신호를 실시간으로 NTSC A/W 스트림으로 변환하는 기능을 수행한다. 따라서 Multi-tasking 방식은 실시간 응용시스템에서 프로세서의 효율적인 사용에 매우 효과적인 방법이다. 본 논문에서는 H/W, S/W micro kernel을 이용한 hybrid approach를 통하여 H/W micro kernel과 multi-tasking programming과의 관계를 적절히 조절하여 시스템의 처리속도를 증가시켰다. 또한 DBS수신기에서의 실시간 처리를 위해 각각의 프로세스들간의 스케줄 적정성을 확보하기 위해 시스템의 요구사항이 만족되도록 개발된 critical hard real-time task들에 대한 스케줄 적정성을 먼저 평가하고, 그 밖의 soft real-time task 들에 대한 스케줄링 가능성에 대한 평가를 진행하여 전체적으로 실시간 처리에 문제가 발생하지 않도록 embedded 소프트웨어를 개발하였다.

• 대한의용생체공학회:의공학회지
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• 제31권3호
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• pp.187-193
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• 2010

In this study we have designed and fabricated an inexpensive micro electronic system that we call Alvitek. It can indirectly but accurately predict and display the partial pressures of alveolar oxygen and carbon dioxide for the patients in the ICU of a hospital. Alvitek consists of both hardware part and software part. Performance of the system is tested by animal experiment with pigs for various $F_{t}e_{2}$ and RR(Respiratory Rate) values under the mechanical ventilation. The predicted alveolar gas partial pressures are cprpared with the approximate alveolar oxygen partial pressures easily calculated by the physician’s bedside formula. As a result, we have concluded that the relative error of A-$aDe_2$ calculated by the bedside formula grows seriously for lower $F_{t}e_{2}$ values. The present prediction method of Alvitek is henceforth believed very meaningful to the physicians. The system hardware and software are described in the text.

• 전기학회논문지
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• 제66권7호
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• pp.1141-1148
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• 2017

Generally, a thermistor made by sintering a metal oxide is widely used to measure the ambient temperature. This thermistor is widely used not only for industrial use but also for medical use because of its excellent sensitivity, durability, temperature change characteristics and low cost. In particular, the normal body temperature is 36.9 degrees relative to the armpit temperature, and it is most closely related to the circulating blood flow. Previous studies have shown that body temperature changes during biomechanical changes and body temperature changes by anomalous signs or illnesses. Therefore, in this study, we propose a Lock-In-Amp design to detect minute temperature changes of clothing and thermistor wired by a preacher as a method to regularly measure body temperature in daily life. Especially, it is designed to measure the minute resistance change of the thermistor according to body temperature change even in a low-cost microprocessor environment by using a micro-processor-based Lock-In-Amp, and a jacquard and the thermistor is arranged so as to be close to the side, so that the reference body temperature can be easily measured. The temperature was measured and stored in real time using short-range wireless communication for non - restraint temperature monitoring. A baby vest was made to verify its performance through temperature experiments for infants. The measurement of infant body temperature through the existing skin sensor or thermometer has limitations in monitoring infant body temperature for a long time without restriction. However, it can be overcome by using the embroidery fabric based micro temperature monitoring wireless monitoring device proposed in this study.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 심포지엄 논문집 정보 및 제어부문
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• pp.141-142
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• 2008

Hearing loss is the most common birth defect among infants. Yet most hearing-impaired children are not identified until 1 to 3 years of age - which is well beyond the critical period(6 month) for healthy speech and language development. However, if a hearing-impairment is identified and treated in its early stages, child's speech and language skills will be comparable to his or her normal- hearing peers. For these reasons, hearing screening at birth and routinely throughout childhood is extremely important. Auditory brain-stem response(ABR) is nowadays one of the most reliable diagnostic tools in the early detection of hard of hearing. In this study, we developed the system that detects auditory evoked potential using micro-processor. Furthermore, it is required to develop a portable system to measure in not only soundproof room but also nursery for infants.

• 제어로봇시스템학회논문지
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• 제19권2호
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• pp.87-94
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• 2013

UKF (Unscented Kalman Filter) has been used in the nonlinear systems without initial accurate state estimates instead of EKF (Extended Kalman Filter) of the last decade because the UKF has robustness to the large initial estimation error. In the multirate integrated system such as INS (Inertial Navigation System)/GPS (Global Positioning System) integrated navigation system, however, it is difficult to implement the UKF based navigation algorithm in the mid-grade micro-processor due to the large computational burden. To overcome this problem, this paper proposes a MUKF (Modified UKF) that has a reduced computation burden using the basic idea that the change of the provability distribution for the state variables between measurement updates is small in the multi-rate INS/GPS integrated navigation filter. The performance of the proposed MUKF is verified by numerical simulations.

• 한국안전학회지
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• 제32권1호
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• pp.21-26
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• 2017

An IoT-based particulate matter (PM2.5) sensing device (PSD) is developed. The PSD consists of a PM2.5 sensor, signal processing circuit, and wi-fi enabled-microprocessor along with temperature and humidity sensors. The PSD estimates PM2.5 density by measuring light scattered by PM2.5. To gauge performance of the PSD, PM2.5 density of open air was measured with the PSD and compared with that of the collocated-government-certified measuring station. Measurements were taken at a sampling frequency of 100 Hz and moving-averaged to remove measurement noise. When compared to the result of the measuring station, average percentile error of PM2.5 density from the PSD is found to be 31%. A correlation coefficient is found to be 0.72 which indicates a strong correlation. Instantaneous variation, however, may far exceed average errors, leading to a conclusion that the PSD is more suitable for estimating average trend of PM2.5 density variations than estimating instantaneous PM2.5 density.

• 한국자동차공학회논문집
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• 제6권3호
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• pp.115-122
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• 1998

For digital engine control timings, such as ignition, are based on the crank shaft angle. Therefore, it is very important that the angle of the crank shaft can be detected with accuracy for optimal ignition timing. Sequential multi-point injection(MPI) systems that have independent injection events for each cylinder, are used to inject an accurate quantity of fuel, and to cope with varying engine status promptly. In this study the distributorless ignition timing. A crankshaft position sensor has been installed such that it generates a number of pulses per crankshaft revolution to permit accurate detection of the crank shaft angle. An event detecting algorithm has been developed, which detects the crank shaft pulses generated by the position sensor, and the software outputs the required control signals at given crank angle values. We clarified that the hardware method is the best way to increase the performance of the control system, because the event detecting duration T(1+2)max becomes zero.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 학술대회 논문집 정보 및 제어부문
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• pp.89-91
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• 2004

In SCADA systems, an RTU is a device installed at a remote location that collects data, codes the data into a format that is transmittable and transmits the data back to a central station, or MTU. An RTU also collects information from the master device and implements processes that are directed by master device. RTUs are equipped with input channels for sensing or metering, output channels for control, indication or alarms and a communications port. In general, the data are transmitted via a wired communication infrastructure such as RS422 or RS485 between RTU and MTU. But, limited range of wired communication doesn't allow the system to cover remote areas over the limitation, and building a wired communication network is not easy in the circumstances. In this Paper, we design and implement a smart cost-effective Web-RTU that can communicate with MTU via Web. Web is of benefit to the Web-RTU, because it is not only free from the distance limitations, but also is built easily and cost-effectively wherever Internet resources are available. Additionally, Web can be easily applied to the SCADA system with the development of hardware and software for communications. The Web-RTU has a program memory, a data memory and a RAM inside, and uses Atmega128, low-cost 8 bit micro-processor with eight AI(Analog Input). It performs well enough to implement all existing roles of RTU.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 A
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• pp.603-605
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• 1996

The SLIM used in the conveyance system has been generally developed the controller based on the slip frequency control and the VVVF method to obtain the quick response for the position control signal. This paper deals with the trust control of the SLIM by vector control with Bang-Bang condition. Also, the control system is composed of the PI controller for soft start of the SLIM and the q-axis current controller for correction in phase with Space Vector for reducing the harmonic pulsation in low speed. The processing for vector control and robust dynamic breaking control is carried out by MC80196KC micro processor and IGBT module. The proposed scheme is verified through the computer simulation and experiments for the 10KW SLIM.