• Journal of the Korean Society for Precision Engineering
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• v.13 no.5
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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.

• Journal of Korean Critical Care Nursing
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• v.16 no.1
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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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• v.65 no.3
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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.

• Journal of Wellbeing Management and Applied Psychology
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• v.5 no.4
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• pp.19-31
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• 2022

Purpose: This study was conducted to identify indoor air quality in various living spaces using sensors that can measure noise, vibration, fine dust, and odor in real time and to propose optimal indoor air quality maintenance management using Internet of Things(IoT). Research design, data and methodology: Using real-time sensors to monitor physical factors and environmental air pollutants that affect the comfort of the residential environment, Noise, Vibration, Atmospheric Pressure, Blue Light, Formaldehyde, Hydrogen Sulfide, Illumination, Temperature, Ozone, PM10, Aldehyde, Amine, LVOCs and TVOCs were measured. It were measured every 1 seconds from 4 offices and 4 stores on a small scale from November 2018 to January 2019. Results: The difference between illuminance and blue light for each measuring point was found to depend on lighting time, and the ratio of blue light in total illumination was 0.358 ~ 0.393. Formaldehyde and hydrogen sulphide were found to be higher than those that temporarily attract people in an indoor office space that is constantly active, requiring office air ventilation. The noise was found to be 50dB higher than the office WHO recommendation noise level of 35 ~ 40dB. The most important factors for indoor environmental quality were temperature> humidity> illumination> blue light in turn. Conclusions: Various factors that determine the comfort of indoor living space can be measured with real-time sensors. Further, it is judged that the use of IoT can help maintain indoor air quality comfortably.

• Physical Therapy Korea
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• v.30 no.3
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• pp.174-183
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• 2023

Background: Office workers experience neck or back pain due to poor posture, such as flexed head and forward head posture, during long-term sedentary work. Posture correction is used to reduce pain caused by poor posture and ensures proper alignment of the body. Several assistive devices have been developed to assist in maintaining an ideal posture; however, there are limitations in practical use due to vast size, unproven long-term effects or inconsistency of maintaining posture alignment. We developed a headphone and necklace posture correction system (HANPCS) for posture correction using an inertial measurement unit (IMU) sensor that provides visual or auditory feedback. Objects: To demonstrate the test-retest reliability and concurrent validity of neck and upper trunk flexion measurements using a HANPCS, compared with a three-dimensional motion analysis system (3DMAS). Methods: Twenty-nine participants were included in this study. The HANPCS was applied to each participant. The angle for each action was measured simultaneously using the HANPCS and 3DMAS. The data were analyzed using the intraclass correlation coefficient (ICC) = [3,3] with 95% confidence intervals (CIs). Results: The angular measurements of the HANPCS for neck and upper trunk flexions showed high intra- (ICC = 0.954-0.971) and inter-day (ICC = 0.865-0.937) values, standard error of measurement (SEM) values (1.05°-2.04°), and minimal detectable change (MDC) values (2.92°-5.65°). Also, the angular measurements between the HANPCS and 3DMAS had excellent ICC values (> 0.90) for all sessions, which indicates high concurrent validity. Conclusion: Our study demonstrates that the HANPCS is as accurate in measuring angle as the gold standard, 3DMAS. Therefore, the HANPCS is reliable and valid because of its angular measurement reliability and validity.

• The Journal of the Convergence on Culture Technology
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• v.9 no.4
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• pp.393-399
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• 2023

Upper limb amputees wear an upper limb prosthesis for both aesthetic purposes and functional necessity, and in particular, in the case of amputee with both hands, it is essential to wear a myoelectric prosthetic hand capable of gripping action. The prosthetic hand operated by the EMG signal of the remaining muscles is a public insurance benefit item of the Industrial Accident Compensation Insurance, and test method standards are needed to be developed for the safety of the user and the effectiveness of the product performance. In this study, we developed systems for measuring the gripping force of myoelectric hand prosthesis by a load cell and for durability test of the prosthesis over repeated use with a proximity sensor, and propose a test method standard. Since the international test method standard has not yet been established, it is expected that Korea will be able to play a leading role in this standardization field in the future.

• Journal of Environmental Health Sciences
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• v.48 no.1
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• pp.44-51
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• 2022

Background: Air pollution is increasing together with industrialization and urbanization. In order to reduce air pollution, public transportation is recommended rather than private cars, and the number of passengers using public transportation is increasing accordingly. This study observes the concentration of indoor pollutants in city buses over time. Through this means, we intend to suggest a plan to manage the indoor air quality in city buses. Objectives: The concentration of indoor pollution in public transportation was investigated from April 2021 to January 2022. Based on this, we evaluated the exposure to indoor pollutants. Methods: Six city bus lines in an industrial city were selected for the research, and indoor pollution was measured through IoT (Internet of Things)-based sensor-type measuring devices. The concentration of pollutants was measured every minute, and statistical data were constructed based on the measurement results. Results: In all the city buses studied, the average concentration of pollutants were below the guidelines. However, some measurement results showed cases of exceeding the guidelines. As a result of the analysis by time zone, there were more cases in which pollutants exceeded the standard value during rush hour compared to at other times. A risk assessment for PM₁₀ was performed by evaluating the excess mortality risk from exposure and the risk from inhalation exposure. Conclusions: All measured indoor pollutants in the city buses did not exceed the guidelines. Also, the risk assessment results were found to be within the level of safety. However, if a city bus is used for a long time, there is a possibility that there may be an impact on the human body due to inhalation exposure, so additional management is required.

• Smart Media Journal
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• v.12 no.5
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• pp.81-87
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• 2023

In this paper, accidents in high-voltage overhead distribution lines, which provide stable power supply in the power system, cause inconvenience in life and disruption of production of companies. 22.9 [kV] high-voltage overhead power distribution lines aim to improve reliability and stability, such as damage caused by rain, snow, wind, etc., or electric shock prevention. Therefore, in order to prevent wire disconnection accidents due to deterioration of electrical conductivity or tensile strength due to corrosion of overhead distribution lines, it is necessary to prevent unexpected accidents in the future through regular inspection and repair. In order to diagnose deterioration due to corrosion of distribution lines, a diagnostic system (measuring instrument) is installed on the wires to monitor the condition of the wires. The manager on the ground receives the measured data through ZigBee wireless communication, controls the diagnosis system through the diagnosis system program, and grasps the condition of the overhead distribution line through the measured data and photographed photos, and predicts the life of the wire along with the visual inspection method. developed a program.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.2D
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• pp.191-198
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• 2010

The displacement of slope is a key factor in predicting the risk of a landslide. Therefore, the slope displacement should be continuously observed with high accuracy. Recently, high-tech equipment such as optical fiber sensor, GPS, total station and measuring instrument have been used. However, such equipment is poorly used in fields due to economics, environment, convenience and management. Because of this, development of substantial observational techniques for varied slope observation and field applications is needed. This study analyzed the possibility of terrestrial LiDAR for slope monitoring and suggested it as information-obtaining technique for slope investigation and management. For that, this study evaluated the monitoring accuracy of terrestrial LiDAR and performed GRID analysis to read the displacement area with the naked eye. In addition, it suggested a methodology for slope monitoring.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.10a
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• pp.229-232
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• 2022

Recently, production of offshore fisheries in Korea has been decreasing. Since production of offshore fisheries in 2016 fell below 1 million tons for the first time in 44 years, it has not recovered and has been decreasing. In order to cope with such a decrease in fishery resources, the TAC (total allowable catch) system is implemented internationally for fisheries resource management. Since 1999, South Korea has introduced the TAC system to perform resource management. In this paper, we propose an artificial intelligence-based fish classification and weight estimation system that can be used to investigate fishery resources of land observers essential for the implementation of the TAC system. The system consists of an app and a cloud server that automatically measures the body size and height of fish and takes photos using a terminal equipped with a lidar sensor. In the cloud server, fish classification is performed using a CNN-based efficientnet model and the weight of fish is predicted using automatically measured body length and body height information. Using this system, it is possible to improve the existing method in which the land observer manually writes after measuring the tape measure and weight in the stomach market.