• 센서학회지
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• 제19권3호
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• pp.209-213
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• 2010

This paper describes the fabrication and characteristics of AlN piezoelectric MPG(micro power generator). The micro energy harvester was fabricated to convert ambient vibration energy to electrical power as a AlN piezoelectric cantilever with Si proof-mass. To be compatible with CMOS process, AlN thin film was grown at low temperature by RF magnetron sputtering and micro power generators were fabricated by MEMS technologies. X-ray diffraction pattern proved that the grown AlN film had highly(002) orientation with low value of FWHM(full width at the half maximum, $\theta=0.276^{\circ}$) in the rocking curve around(002) reflections. The implemented harvester showed the $198.5\;{\mu}m$ highest membrane displacement and generated 6.4 nW of electrical power to $80\;k{\Omega}$ resistive load with $22.6\;mV_{rms}$ voltage from 1.0 G acceleration at its resonant frequency of 389 Hz. From these results, the AlN piezoelectric MPG will be possible to suitable with the batch process and confirm the possibility for power supply in portable, mobile and wearable microsystems.

• 한국연소학회지
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• 제9권3호
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• pp.27-35
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• 2004

Diode laser absorption sensors are advantageous because they may provide fast, sensitive, absolute, and selective measurements of species concentration. These systems are very attractive for practical applications owing to its compactness, resonable cost, robustness, and ease of use. In addition, diode lasers are fiber-optic compatible and thus enable simultaneous measurements of multiple species along a line-of-sight. Recent advances of room-temperature, near-IR and visible diode laser sources for telecommunication, optical data storage applications make it possible to be applied for combustion diagnostics based on diode laser absorption spectroscopy. Therefore, combined with fiber-optics and high sensitive detection strategies, compact and portable sensor systems are now appearing for variety of applications. The objectives of this research are to develope a new gas sensing system and to verify feasibility of this system. Wavelength and power characteristics as a function of injection current and temperature are experimentally found out. Direct absorption spectroscopy has been demonstrated in these experiments and has a bright prospect to this diode laser system.

• Journal of Electrical Engineering and Technology
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• 제8권4호
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• pp.872-878
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• 2013

In industrial control systems, flow measurement is a very important issue. It is frequently needed to calculate how much total fluid or gas flows through a cross-section. Flow volume measurement tools use simple sampling or rectangle methods. Actually, flow volume measurement process is an integration process. For this reason, measurement systems using instantaneous sampling technique cause considerably high errors. In order to make more accurate flow measurement, numerical integration methods should be used. Literally, for numerical integration method, Rectangular, Trapezoidal, Simpson, Romberg and Gaussian Quadrature methods are suggested. Among these methods, trapezoidal rule method is quite easy to calculate and is notably more accurate and contains no restrictive conditions. Therefore, it is especially convenient for the portable flow volume measurement systems. In this study, the volume measurement of air which is flowing through a cross-section is achieved by using PLC ladder diagram. The measurements are done using two different approaches. Trapezoidal rule method is proposed to measure the flow sensor signal to minimize measurement errors due to the classical sampling method as a different approach. It is concluded that the trapezoidal rule method is more effective than the classical sampling.

• International Journal of Internet, Broadcasting and Communication
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• 제11권4호
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• pp.11-17
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• 2019

Plantar pressure data can be used not only for walking patterns in daily life, but also for eating, health care, and disease prevention. For this reason, the importance of plantar pressure measurement has recently increased. However, most systems that can measure both static and dynamic plantar pressure at the same time are expensive, not portable, and not universal. In this study, we propose a system that effectively reduces the number of sensors in plantar pressure system. Through this, we want to increase the economics and practicality by reducing the size and weight of the system, as well as the power consumption. First, for static plantar pressure and dynamic plantar pressure, the values measured by existing precision instruments are analyzed to determine how many measurement parts the insole is divided into. Next, for the divided measuring parts, the position of the sensor is determined by calculating the Center of Pressure (COP) for each part with the values of all dynamic and static plantar pressure sensors. Finally, in order to construct a personalized plantar pressure measurement system, we propose a weighting method for the static plantar pressure COP and the dynamic plantar pressure COP for each part.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2014년도 추계학술대회
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• pp.785-788
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• 2014

세계 제1의 선박 건조 강국임에도 불구하고 최근 건조 과정에서 많은 인재 및 재난 사고가 많이 일어나고 있으며, 현재 대형 및 중소 조선소들은 안전 관리 대책에 많은 관심을 보이고 있다. 이에 따라 조선소에서는 인적감시 시스템, RF 무선통신 시스템, 이동용 측정 시스템과 같은 시스템을 적용하여 화재 및 질식사 등의 사고를 예방하는 재해방지 감시시스템 개발에 주력하고 있다. 본 논문은 재해 관련 시스템을 적용하고 있는 조선소들의 기존 시스템을 분석하고, 최신 ICT 기술을 이용하여 24시간 재해 상황 전시 및 통보를 실시간으로 감시하는 재해방지 감시시스템을 개발하고, 실제 적용하여 사전에 안전 재난 사고를 방지하는 것이 가능하다.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2009년도 추계학술대회
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• pp.1049-1052
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• 2009

기존의 응급 호출 시스템이 가지고 있는 휴대성의 단점을 보완하기 위하여 무선 센서 네트워크를 이용한 지능형 개인 응급 호출 시스템을 제안한다. 제안한 시스템은 개인용 호출 노드, 멀티홉 통신을 위한 중계 노드, 서버부로 구성된다. 개인용 송신 노드는 동작 상태와 배터리양을 확인할 수 있고, RSSI를 이용하여 응급 호출을 한 개인의 위치를 제공한다. 제안한 무선 너스 콜 시스템이 기존 너스 콜 시스템이 가지는 단점을 보완하는 것을 실험을 통하여 확인하였다.

• 센서학회지
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• 제31권1호
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• pp.57-63
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• 2022

This study describes a system that monitors the tool and cutting state of automatic beveling operation in real time. As a signal for cutting state monitoring, a motor current detected from the spindle drive system of the automatic beveling machine is used to monitor abnormal state. Because automatic beveling is processed using a face milling cutter, the cutting force mechanism is the same as the milling process. The predicted cutting torque is obtained using a cutting force model based on specific cutting resistance. Then, the predicted cutting torque is converted into the spindle motor current value, and cutting state stability is diagnosed by comparing it with the motor current value detected during beveling operation. The experimental results show that the spindle motor current can detect abnormal cutting state such as overload and tool wear during beveling operation, and can diagnose the cutting stability using the proposed equip-current line diagram.

• Design & Manufacturing
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• 제16권1호
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• pp.1-8
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• 2022

The importance of fast and accurate body temperature measurement with a portable thermometer is increasing. In order to reduce the temperature measurement response time of the infrared ear thermometer, it is very important to develop a structure for a thermometer having an efficient heat transfer path. Most of the existing ear thermometers are single structures that do not consider thermal efficiency, which may delay measurement time and reduce measurement accuracy. Therefore, in this study, the upper part of the thermometer in contact with the ear is made of a thermally conductive material, and the lower part of the thermometer is made of a thermal barrier material so that heat can be concentrated on the infrared sensor of the thermometer by blocking the upper part of the heat. For the efficiency of production, it was intended to be manufactured through the double injection process, and for this purpose, in this paper, the optimal process parameters were derived through the double injection process analysis.

• 대한예방한의학회지
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• 제26권2호
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• pp.25-35
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• 2022

Objectives : This study aims to analyze the patents filed in the clinical diagnosis sector where technologies have been actively developed since the advent of the 4th industrial revolution. Methods : The analysis has been conducted in two ways - the period from 2016 to 2021 and the time points before and after COVID-19 - by visualizing based on the word cloud method. Results : Over two thirds of patents has been filed in the A61B sector (71.8%) and cure, sensor, self diagnosis, control, and breakdown have been observed in the period above. During the overall period (2016~2021), 'ultrasound'(7.5%), 'image'(5.1%), 'skin'(4.0%), 'treatment'(3.4%), and 'artificial intelligence(2.5%)' were the frequently patent applications technologies. In addition, 'ultrasound'(6.2%), 'image'(5.5%), 'skin'(4.0%), 'treatment' (3.7%), and 'portable'(1.7%) appeared most frequently before COVID-19 whereas 'ultrasound(5.5%)', 'artificial intelligence(4.2%)', 'diagnostic device'(1.9%), 'dimentia'(1.6%), and 'diagnostic kit'(1.4%) emerged the most after COVID-19. Conclusion : This study is meaningful in that it showed the technological development trend in the digital diagnosis sector and it was found that the Korean medicine field should contribute to this field more actively in the future.

• Journal of Microbiology and Biotechnology
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• 제33권5호
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• pp.559-573
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• 2023

Shiga toxin (Stxs)-producing enterohaemorrhagic Escherichia coli (EHEC) and Shigella dysenteriae serotype 1 are major causative agents of severe bloody diarrhea (known as hemorrhagic colitis) and hemolytic uremic syndrome (HUS) associated with extraintestinal complications such as acute renal failure and neurologic impairment in infected patients under 9 years of age. Extreme nephrotoxicity of Stxs in HUS patients is associated with severe outcomes, highlighting the need to develop technologies to detect low levels of the toxin in environmental or food samples. Currently, the conventional polymerase chain reaction (PCR) or immunoassay is the most broadly used assay to detect the toxin. However, these assays are laborious, time-consuming, and costly. More recently, numerous studies have described novel, highly sensitive, and portable methods for detecting Stxs from EHEC. To contextualize newly emerging Stxs detection methods, we briefly explain the basic principles of these methods, including lateral flow assays, optical detection, and electrical detection. We subsequently describe existing and newly emerging rapid detection technologies to identify and measure Stxs.