• 센서학회지
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• 제31권5호
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• pp.343-347
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• 2022

Recently, the problem of global warming caused by greenhouse gases is getting serious due to the development of industry and the increase in transportation means. Accordingly, the need for a technology to reduce carbon dioxide, which accounts for most of the greenhouse gas, is increasing. Among them, a catalyst for converting carbon dioxide into fuel is being actively studied. Catalysts for reducing carbon dioxide are classified into thermal catalysts and photocatalysts. In particular, the photocatalyst has the advantage that carbon dioxide can be reduced only by irradiating ultraviolet rays at room temperature without high temperature or additional gas. TiO₂ is widely used as a photocatalyst because it is non-toxic and has high stability, but has a disadvantage of low carbon dioxide reduction efficiency. To increase the reduction efficiency, 1-propanol was used in the synthesis process. This prevents agglomeration of the catalyst and increases the specific surface area and pores of TiO₂, thereby increasing the surface area in contact with carbon dioxide. As a result of measuring the CO₂ reduction efficiency, it was confirmed that the efficiency of TiO₂ with 1-propanol and TiO₂ without 1-propanol was 19% and 12.3%, respectively, and the former showed a 1.5 times improved efficiency.

• 한국근적외분광분석학회:학술대회논문집
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• 한국근적외분광분석학회 2001년도 NIR-2001
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• pp.1267-1267
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• 2001

The existing fruit sorter has the method of tilting tray and extracting fruits by the action of solenoid or springs. In peaches, the most sort processing is supported by man because the sorter make fatal damage to peaches. In order to sustain commodity and quality of peach non-destructive, non-contact and real time based sorter was needed. This study was performed to develop peach sorter using near-infrared spectroscopy in real time and nondestructively. The prototype was developed to decrease internal and external damage of peach caused by the sorter, which had a way of extracting tray with it. To decrease positioning error of measuring sugar contents in peaches, fiber optic with two direction diverged was developed and attached to the prototype. The program for sorting and operating the prototype was developed using visual basic 6.0 language to measure several quality index such as chlorophyll, some defect, sugar contents. The all sorting result was saved to return farmers for being index of good quality production. Using the prototype, program and MLR(multiple linear regression) model, it was possible to estimate sugar content of peaches with the determination coefficient of 0.71 and SEC of 0.42bx using 16 wavelengths. The developed MLR model had determination coefficient of 0.69, and SEP of 0.49bx, it was better result than single point measurement of 1999's. The peach sweetness grading system based on NIR reflectance method, which consists of photodiode-array sensor, quartz-halogen lamp and fiber optic diverged two bundles for transmitting the light and detecting the reflected light, was developed and evaluated. It was possible to predict the soluble solid contents of peaches in real time and nondestructively using the system which had the accuracy of 91 percentage and the capacity of 7,200 peaches per an hour for grading 2 classes by sugar contents. Draining is one of important factors for production peaches having good qualities. The reason why one farm's product belows others could be estimated for bad draining, over-much nitrogen fertilizer, soil characteristics, etc. After this, the report saved by the peach grading system will have to be good materials to farmers for production high quality peaches. They could share the result or compare with others and diagnose their cultural practice.

• 농업과학연구
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• 제49권4호
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• pp.845-855
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• 2022

The purpose of this study is to develop a self-propelled underground crop harvester and its performance was evaluated by measuring the load during actual potato harvesting operations. This study was conducted at a constant working speed of 1 km·h^-1. A load measurement system was installed to measure the actual load and the required working power was analyzed. A hydraulic pressure sensor was also installed to measure the hydraulic pressure. The required hydraulic power was calculated using the hydraulic pressure and flow rate. The results showed that the engine speed, torque, and power during harvesting operation were in the range of 845 - 1,423 rpm, 95 - 228 Nm, and 9 - 31 kW, respectively. Traction power, excluding the hydraulic pump of the tractor and power take-off (PTO) output, was in the range of 9 - 28 kW, and it was confirmed that it occupies a ratio of 16.2 to 50% of the engine rated output. The engine can supply the minimum required traction power to move the vehicle. This means that the engine used in this study could be down-sized to be suitable for an underground crop harvester. In this study, the gear stages of the tractor were not considered. This research thus shows the possibility of developing a self-propelled underground crop harvester.

• Design & Manufacturing
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• 제17권1호
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• pp.56-63
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• 2023

In this study, the vibration signal of the mold was measured and analyzed to monitor the process information and characteristics during the press molding process. A necklace-type picture frame mold was used for press molding, and the vibration signal was measured by GY-61 acceleration sensor module attached to the surface of the upper (movable) mold base. The change of the vibration signal of the mold according to press speed was analyzed. As a result, the vibration signal had a large change at five sections: "Holder contact", "Punch contact and start of pressing", "End of pressing", "Mold open", and "Demolding". The time difference between "Punch contact and start of pressing" and "End of pressing" means the pressing time which is the actual time the material is molded under pressing pressure. The time intervals for each section, represented by the time interval between "Holder contact" and "Punch contact and start of pressing", can be used to compare and evaluate the press speed applied to the process. By comparing the vibration signals at 60 rpm and 90 rpm, the amplitude at the section of "Punch contact and start of pressing" increased as the press speed increased. This result means that as the press speed increases, more force and pressure is applied to the material. Also, the peak values of the other sections were found to increase as the press speed increased. It was found that the pressing time, the time interval between "Punch contact and start of pressing" and "End of pressing", decreases as the pressing speed increases. Similarly, press speed factor, the time interval between "Holder contact", and "Punch contact and start of pressing", is found to be shorter. Therefore, based on the result of this study, the pressing time, press speed, pressing(punching) pressure of each cycle can be monitored by measuring the vibration signal of the mold. Also, it was confirmed that the level and trend of process information and characterization can be evaluated as the change of the mold vibration during press molding.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2004년도 제22회 춘계학술대회논문집
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• pp.802-806
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• 2004

For the protection of the local air quality and the global atmosphere, the emissions of trace species including nitric oxides (NO and NO$_2$) from gas turbines are regulated by local governments and by the International Civil Aviation Organization. In-situ measurements of such species are needed not only for the development of advanced low-emission combustion concepts but also for providing emissions data required for the sound assessment of the effects of the emissions on environment. We have been developing a laser absorption system that has a capability of simultaneous determination of NO and NO$_2$concentrations in the exhaust jets from aero gas turbines. A diode laser operating near 1.8 micrometer is used for the detection of NO while a separated visible tunable diode laser operating near 676 nanometers is used for NO$_2$. The sensitivities at elevated temperature conditions were determined for simulated gas mixtures heated up to 500K in a heated cell of a straight 0.5 m optical path. Sensitivity limits estimated as were 30 ppmv-m and 3.7 ppmv-m for NO and NO$_2$, respectively, at a typical exhaust gas temperature of 800K. Experiments using the simulated exhaust flows have proven that $CO_2$ and $H_2O$ vapor - both major combustion products - do not show any interference in the NO or NO$_2$ measurements. The measurement system has been applied to the NO/NO$_2$ measurements in NO and NO$_2$ doped real combustion gas jets issuing from a rectangular nozzle having 0.4 m optical path. The lower detection limits of the system were considerably decreased by using a multipass optical cell. A pair of off-axis parabola mirrors successfully suppressed the beam steering in the combustion gas jets by centralizing the fluctuating beam in sensor area of the detectors.

• 한국산업정보학회논문지
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• 제14권5호
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• pp.125-130
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• 2009

현대 사회에서 거동이 불편한 장애인이나 독거노인들은 지속적인 관심과 사회적인 책임이 요구 되고 있으나 현실적으로 어려움이 많다. 본 논문에서는 장애인이나 노약자의 건강상태 (온도 및 맥박수)를 측정하고 비상상황이 발생할 경우 가족, 병원의 담당의사에게 휴대전화를 통하여 통보하며 측정된 데이터를 DB화하는 건강관리 시스템을 구현하였다. 본 시스템은 조도센서와 고휘도 LED를 이용하여 손가락의 혈류를 감지를 통해 맥박수와 비접촉식 은도센서를 이용하여 원하는 물체의 온도를 동시에 측정하는 방식을 구현하여 LCD에서 확인이 가능하도록 개발하였다. 또한 측정값을 지그비 통신을 이용하여 사용자가 서버컴퓨터로 측정값을 전송하여 측정된 간을 관측하고 DB화하여 측정된 값, 평균, 측정된 시간을 주기적으로 저장할 수 있도록 하였다. 몸에 이상이 있을 경우 보호자, 의사 및 119구급대에 문자를 전송하여 위급 상황을 대처할 수 있도록 구현하였다.

• 한국산업정보학회논문지
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• 제15권4호
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• pp.53-60
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• 2010

생체인식은 개인의 신체에서 얻어지는 고유한 특성을 특징점으로 잡아 인식하는 방법으로서 분실할 위험이 없고 타인에 의한 위 변조의 위험성이 낮아 높은 보안성을 제공한다. 본 논문에서는 빠르고 편리하게 광학적으로 두 손가락 끝에서 정확한 심장박동 신호를 측정하여 '생체인식에 적용할 수 있는 광용적맥파를 이용한 생체인식 보안시스템을 설계 및 구현하였다. 성능평가 결과, 본 논문에서 설계 및 구현된 개인인증을 위한 생체인식 보안시스템은 출입문의 개폐용으로 실험한 결과 평균 90.5%의 인식률을 나타내었다. 제안된 생체인식 보안시스템은 간단하게 손가락을 기계에 접촉하는 원터치 방식으로 원하는 생체 정보를 얻음으로써 시간적 편리성과 누구나 거부감 없이 쉽게 이용할 수 있는 장점이 있다.

• 한국정밀공학회지
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• 제13권5호
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• pp.84-94
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• 1996

In order to prevent shell sticking by providing sufficient lubrication between the strand and the mold, the mold oscillation has been used. Now it is well known that the shape of the oscillation curve has a decisive effect on the surface quality of the cast product. Besides, oscillation parameters such as stroke and frequency are also very important. In order to guarantee that parameters which have been found to be optimal for a certain grade of steel do not change with time, periodical checks of the physical condition of the whole equipment are necessary. The portable mold oscillation analyzer with integrated computer, developed by POSCO, records the movement of the mold in every spatial direction. The system uses the gap sensors to measure the mold movement (displacement ) in the two horizontal directions according to the mold narrow and broad faces and the vertical strokes in the four corners of mold. The gap sensor is a non-contacting minute displacement measuring device using the principle of high frequency eddy current loss. The mold oscillation diagnosis system integrates the gap sensors, their converters and the industrial portable computer with plug-in data acquisition boards. The all programs, such as the fast Fourier transformation module (amplitude and phase spectrums) and harmonic analysis module, was coded by LabVIEW$^{TM}$ software as the graphical language. In an own 'expert module' which is included in the diagnosis program, one can obtain much information about the mold oscillation equipment.

• 중환자간호학회지
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• 제16권1호
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• pp.1-14
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• 2023

Purpose : This study aimed to compare peripheral pulse oxygen saturation (SpO₂) values, measured at different monitoring sites, and arterial oxygen saturation (SaO₂) of neurocritical patients. Methods : The study included 110 patients admitted to the neurosurgical intensive care unit of a university hospital. The patients' SpO₂ values were measured in their index fingers, both second toes, both earlobes, and foreheads, using the patient monitoring system. These values were compared with the standard value of SaO₂ measured using a blood gas analyzer. Data were analyzed using descriptive values, Pearson's correlation coefficients, Lin's concordance correlation coefficients (CCC), and Bland-Altman plots. Result : Regardless of the measuring site, SpO₂ was correlated with the paired measurements of SaO₂ (r=.40~.60, p<.001, CCC range=.40~.58). No significant bias in paired measurements of SpO₂ and SaO₂ was observed at all sites (-0.06~0.19%, p>.05). SpO₂ values at the left finger and right earlobe had the narrowest range, with a 95% limits of agreement (LOA) (left finger -3.04~2.93% and right earlobe -3.18~2.79%). SpO₂ at the index finger, on the side without an arterial catheter, had a narrower range of 95% LOA than that of the opposing finger (-3.00~2.97% vs. -3.73~3.26%). Conclusion : SpO₂ at the finger without an arterial catheter had the highest level of precision. This study suggests using the index finger, on the side without an arterial catheter, for pulse oximetry in neurocritical patients.

• Journal of Animal Science and Technology
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• 제65권3호
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• pp.638-651
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• 2023

The objective of this study was to quantitatively estimate the level of grazing area damage in outdoor free-range pig production using a Unmanned Aerial Vehicles (UAV) with an RGB image sensor. Ten corn field images were captured by a UAV over approximately two weeks, during which gestating sows were allowed to graze freely on the corn field measuring 100 × 50 m². The images were corrected to a bird's-eye view, and then divided into 32 segments and sequentially inputted into the YOLOv4 detector to detect the corn images according to their condition. The 43 raw training images selected randomly out of 320 segmented images were flipped to create 86 images, and then these images were further augmented by rotating them in 5-degree increments to create a total of 6,192 images. The increased 6,192 images are further augmented by applying three random color transformations to each image, resulting in 24,768 datasets. The occupancy rate of corn in the field was estimated efficiently using You Only Look Once (YOLO). As of the first day of observation (day 2), it was evident that almost all the corn had disappeared by the ninth day. When grazing 20 sows in a 50 × 100 m² cornfield (250 m²/sow), it appears that the animals should be rotated to other grazing areas to protect the cover crop after at least five days. In agricultural technology, most of the research using machine and deep learning is related to the detection of fruits and pests, and research on other application fields is needed. In addition, large-scale image data collected by experts in the field are required as training data to apply deep learning. If the data required for deep learning is insufficient, a large number of data augmentation is required.