• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 심포지엄 논문집 정보 및 제어부문
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• pp.147-149
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• 2004

Although most of the people have studied English for a long time, their English conversation capability is low. When we provide them portable conversational-type English learners by the application of computer and information process technology, such portable learners can be used to enhance their English conversation capability by their conventional conversation exercises. The core technology to develop such learner is the development of a voice recognition and synthesis module under an embedded environment. This paper deals with voice recognition and synthesis, prototype of the learner module using a DSP(Digital Signal Processing) chip for voice processing, voice playback function, flash memory file system, PC download function using USB ports, English conversation text function by the use of SMC(Smart Media Card) flash memory, LCD display function, MP3 music listening function, etc. Application areas of the prototype equipped with such various functions are vast, i.e. portable language learners, amusement devices, kids toy, control by voice, security by the use of voice, etc.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 신호처리소사이어티 추계학술대회 논문집
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• pp.517-520
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• 2003

Commercial video scope use CCD sensor and frame grabber for image capture and A/D interface but application limited by input resolution and high cost. In this paper we introduce portable video scope using CMOS sensor, USB pen and tuner card (low frame grabber) in place of commercial CCD sensor and frame grabber. Our video scope serves as an essential link between advancing commercial technology and research, providing cost effective solutions for educational, engineering and medical applications across an entire spectrum of needs. The software implementation is done using Direct Show in second version after initial trials using First version VFW (video for window), which gave very low frame rate. Our video scope operates on windows 98, ME, XP, 2000. The drawback of our video scope is crossover problem in output images caused due to interpolation, which has to be rectified for more efficient performance.

• 신재생에너지
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• 제1권1호
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• pp.72-78
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• 2005

Optimal design and proper operation are important to get aimed output power of a polymer electrolyte membrane fuel cell (PEMFC) stack. An air cooling fuel cell stack is widely used in sub kW PEMFC systems. The purpose of this study is to analyze operating conditions affecting the performance of the air cooling PEMFC which is designed for portable application. In portable applications, air cooling stack is difficult to maintain well balanced operating conditions. The importart parameters are the relative humidity, the temperature of the stack, the utilization of reactant gas and so on. in this study, a 500W air cooling PEMFC was fabricated and tested to evaluate the design performance and to determine optimal operating conditions. Moreover, basic modeling also is carried out. These results can be used 3s design criteria and optimal operating conditions for portable PEMFCs

• 한국안전학회지
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• 제38권3호
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• pp.110-120
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• 2023

Following the Fukushima accident, portable equipment employed as accident mitigating systems have been installed and operated to reduce core damage and large early release frequencies. In addition, the establishment of an accident management strategy has gained importance. This study investigated the current status of portable equipment including the international portable equipment FLEX (diverse and flexible coping strategies), and domestic portable equipment multi-barrier accident coping strategy (MACST). Research on optimal utilization of MACST remains insufficient. As a preliminary study for establishing an optimal strategy, sensitivity studies were conducted to facilitate the priority of use on portable equipment, number of portable equipment, and dependency of operator actions based on a multi-unit probabilistic safety assessment model. The results revealed the conditions that reduced the multi-unit and site conditional core damage probabilities, indicating the optimal strategy of MACST. The results of this study can be used as a reference for establishing an optimal strategy that utilizes domestic safety equipment in the future.

• 전기학회논문지
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• 제67권12호
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• pp.1641-1647
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• 2018

In this paper, we describe a portable potentiostat which is capable of cyclic voltammetry(CV) and amperometry for electrochemical dissolved oxygen sensor. In addition, this portable potentiostat can also transmit the measured data wirelessly to android devices such as smart phone, tablet, etc. through Bluetooth. The potentiostat system consists of three parts; a voltage generator circuit which is controlled by Arduino nano and 12-bit DAC(digital to analog converter) to generate necessary electric potential for operating the electrochemical sensor, an oxidation/reduction current measurement circuit, and a Bluetooth module to transmit data wirelessly to an android device. Once measurements are carried out with the android application, the measured data is transmitted to the android device via Bluetooth and displayed using the android app. in real time. In this paper, we report the measured reduction current with a fabricated dissolved oxygen sensor in both saturated-oxygen state and zero-oxygen states. The results of the developed portable potentiostat system are in good agreement with those of the commercial portable potentiostat (${\mu}stat200$, Dropsens inc.). The measured peak reduction currents using the developed potentiostat and the commercial ${\mu}stat200$ potentiostat were $-0.755{\mu}A$ and $-0.724{\mu}A$, respectively. The reduction currents measured at zero-oxygen state were $-0.005{\mu}A$ and $-0.004{\mu}A$. The discrepancy between those two systems seems very small, which implies successful development of a portable and wireless potentionstat.

• 반도체디스플레이기술학회지
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• 제20권1호
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• pp.7-11
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• 2021

The electrocardiogram(ECG) and heart rates are essential for diagnosing heart disease. However, conventional portable ECG devices are possible to only measure heart rates or have limitations in how and where they are measured. In this paper, a portable ECG system in which ECG waveforms and heart rates are displayed on smartphone screens is developed. A smartphone is used as display equipment instead of a computer screen for continuous monitoring. The developed ECG system filters and amplifies detected analog ECG signals. Next, it converts the amplified analog ECG signals into digital signals, then transmits to the smartphone via Bluetooth communication. This ECG system can display and store biomedical signals on a smartphone through the application. As a result, the waveform and heart rates of the developed portable ECG system has been confirmed to be similar to those of existing medical devices.

• 한국재난정보학회 논문집
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• 제8권3호
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• pp.304-309
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• 2012

국립환경과학원은 화학테러 사고 현장의 고체시료 사건원인 물질을 신속히 분석하고자 Portable FT-IR(Fourier Transform Infrared Spectroscopy, A2 Technologies, U.S.A.), Portable XRD(X-ray Diffraction, Olympus Innov-X co., U.S.A.) 등을 보유 및 운용하고 있다. Portable 분석장비의 효율적인 활용과 신속한 분석 값을 얻기 위해 사건현장에서의 탐지 및 시료채취, 현장분석 절차가 필요하다. Portable FT-IR, XRD의 분석결과 값의 정확도는 높으나, 사건현장 중심의 분석절차가 마련되지 않아 비상시 장비사용의 어려움을 가지고 있다. 이에 고체상 Portable 분석장비의 현장 분석방법 및 절차를 마련하여 현장대응에 적극 활용하고자 한다.

• 대한안전경영과학회지
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• 제23권1호
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• pp.9-15
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• 2021

The leading source of occupational fatalities is a portable ladder in Korea because it is widely used in industry as work platform. In order to reduce victims, it is necessary to establish preventive measures for the accidents caused by portable ladder. Therefore, this study statistically analyzed injury death by portable ladder for recent 10 years to investigate the accident characteristics. Next, to monitor wearing of safety helmet in real-time while working on a portable ladder, this study developed an object detection model based on the You Only Look Once(YOLO) architecture, which can accurately detect objects within a reasonable time. The model was trained on 6,023 images with/without ladders and safety helmets. The performance of the proposed detection model was 0.795 for F1 score and 0.843 for mean average precision. In addition, the proposed model processed at least 25 frames per second which make the model suitable for real-time application.

• 센서학회지
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• 제14권2호
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• pp.69-77
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• 2005

The electronic nose (e-nose) has been used in food industry and quality controls in plastic packaging. Recently it finds its applications in medical diagnosis, specifically on detection of diabetes, pulmonary or gastrointestinal problem, or infections by examining odors in the breath or tissues with its odor characterizing ability. Moreover, the use of portable e-nose enables the on-site measurements and analysis of vapors without extra gas-sampling units. This is expected to widen the application of the e-nose in various fields including point-of-care-test or e-health. In this study, a PDA-based portable e-nose was developed using micro-machined gas sensor array and miniaturized electronic interfaces. The rich capacities of the PDA in its computing power and various interfaces are expected to provide the rapid and application specific development of the diagnostic devices, and easy connection to other facilities through information technology (IT) infra. For performance verification of the developed portable e-nose system, Six different vapors were measured using the system. Seven different carbon-black polymer composites were used for the sensor array. The results showed the reproducibility of the measured data and the distinguishable patterns between the vapor species. Additionally, the application of two typical pattern recognition algorithms verified the possibility of the automatic vapor recognition from the portable measurements. These validated the portable e-nose based on PDA developed in this study.

• 한국산업정보학회논문지
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• 제20권4호
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• pp.67-73
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• 2015

최근 재료의 물성평가에 있어 표면마찰 특성이 많이 요구되고 있는 바, 본 연구에서는 휴대 가능한 보급형 마찰계수 시험기의 개발을 다루며, 이는 기구 설계 및 적용, 측정회로의 설계 및 배치, 마이크로프로세서 기반 펌웨어의 구성을 포함한다. 또한 기존의 규격 시험기와 성능 비교를 통하여 본 휴대용 마찰계수 시험기의 실 적용성을 보였다.