• Journal of Aerospace System Engineering
• /
• v.16 no.3
• /
• pp.99-104
• /
• 2022

Aircraft pylon connects the engine or external stores to the main wing, and transfers the load acting on the pylon to the main structure of the aircraft. In particular, it should perform the function of separating the external store mounted on the pylon in case of emergency or mission performance. At this time, if the separation of the external store is not performed properly due to peripheral air flow or functional problems during the separation process of the external store, it may seriously impact the survivability of the aircraft. For this reason, to apply an external attachment to an aircraft, it is necessary to prove the stability of the external attachment in the separation situation in advance. In this paper, we present the result of the ground separation test performed to confirm that the external fuel tank, which is an external attachment, can be safely separated from the pylon. As a result of the test, the separation movement of the external fuel tank was measured with a high-speed camera, and the stability of the separation of the external fuel tank from the pylon were confirmed through the ground separation test. Additionally, the test result provides basic data for the stability evaluation of the separation of external attachments in actual aircraft.

• Science of Emotion and Sensibility
• /
• v.24 no.4
• /
• pp.107-116
• /
• 2021

This study aims to investigate the effect of multisensory stimulation on relieving the stress experienced by drivers. The photoplethysmograms (PPGs) of 30 healthy subjects were measured, and their subjective response to stressful situations and normal driving were evaluated. The subjects underwent nonstimulation and multisensory stimulation in stressful driving situations. Heart rate estimation from the PPG was collected via an ear-type sensor to reduce movement noise. The signals acquired were sampled at 200 Hz using BIOPAC PPG100C. Heart rate variability (HRV) was analyzed to compare the effect of multisensory stimulation on stress situations. In the multisensory stimulation, blue, green, and yellow were used for the visual sensory system; white, pink, and brown noises were used for the auditory sensory system; and lavender, lemon, and rosemary were used for the olfactory sensory system. No difference was observed in the subjective evaluation; however, the HRV results showed an increased HF (%) and decreased LF (%) and LF/HF (%) in the multisensory stimulation (e.g., green, pink noise, and rosemary) when compared to the nonstimulation.

• Journal of the Korean Society of Radiology
• /
• v.16 no.2
• /
• pp.123-129
• /
• 2022

Recently, the penetration rate of Magnetic Resonance Imaging (MRI) is higher than the average among OECD member countries, and the number of MRI scans is increasing. However, MRI scans take longer than other medical devices, and patient movement must be minimized. Therefore, patient discomfort always follows. When the examination is performed in the discomfort of the patient, it is difficult to perform an accurate examination, and it is difficult to obtain an image of diagnostic value. So, in the past, the patient was asked to read the written guide for the risk and cooperation of MRI, but it was composed of technical terms and difficult-to-understand sentences, so it was difficult to understand. The purpose of this study is to supplement these problems and increase the understanding of MRI scans to help acquire images of diagnostic value. In addition, it is intended to evaluate the excellence of leaflet education by evaluating the understanding and satisfaction of patients. As shown in the results of this study, understanding and satisfaction scores were higher after education than before leaflet education, and it was found that there was a difference in understanding according to academic background. However, there was no difference in the number of MRI scans. That is, there was no difference in the number of inspections due to leaflet education. In the future, leaflet education will be widely used for MRI examination, and it is necessary to study the qualitative evaluation of images after leaflet education in the future.

• Journal of Broadcast Engineering
• /
• v.28 no.2
• /
• pp.213-229
• /
• 2023

In this paper, we introduce a spatial sound rendering system that provides 6DoF spatial sound in real time in response to the movement of a listener located in a virtual environment. This system was implemented using MPEG-I AEP as a development environment for the CfP response of MPEG-I Immersive Audio and consists of an encoder and a renderer including a decoder. The encoder serves to offline encode metadata such as the spatial audio parameters of the virtual space scene included in EIF and the directivity information of the sound source provided in the SOFA file and deliver them to the bitstream. The renderer receives the transmitted bitstream and performs 6DoF spatial sound rendering in real time according to the position of the listener. The main spatial sound processing technologies applied to the rendering system include sound source effect and obstacle effect, and other ones for the system processing include Doppler effect, sound field effect and etc. The results of self-subjective evaluation of the developed system are introduced.

• Journal of Intelligence and Information Systems
• /
• v.29 no.1
• /
• pp.107-119
• /
• 2023

The technology that recognizes a soldier's motion and movement status has recently attracted large attention as a combination of wearable technology and artificial intelligence, which is expected to upend the paradigm of troop management. The accuracy of state determination should be maintained at a high-end level to make sure of the expected vital functions both in a training situation; an evaluation and solution provision for each individual's motion, and in a combat situation; overall enhancement in managing troops. However, when input data is given as a timer series or sequence, existing feedforward networks would show overt limitations in maximizing classification performance. Since human behavior data (3-axis accelerations and 3-axis angular velocities) handled for military motion recognition requires the process of analyzing its time-dependent characteristics, this study proposes a high-performance data-driven classifier which utilizes the long-short term memory to identify the order dependence of acquired data, learning to classify eight representative military operations (Sitting, Standing, Walking, Running, Ascending, Descending, Low Crawl, and High Crawl). Since the accuracy is highly dependent on a network's learning conditions and variables, manual adjustment may neither be cost-effective nor guarantee optimal results during learning. Therefore, in this study, we optimized hyperparameters using Bayesian optimization for maximized generalization performance. As a result, the final architecture could reduce the error rate by 62.56% compared to the existing network with a similar number of learnable parameters, with the final accuracy of 98.39% for various military operations.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.30 no.1D
• /
• pp.79-87
• /
• 2010

The urban street has been escaped from functional and uniformed arrangement for merely movement to the space which can take the role of cozy and familiar culture. Therefore I tried to prepare a plan for the wide roads having streetscape which reveal area's identity as well as coziness and convenience by grasping the problem and its solution through analysing and deducing various elements with the subject of streetscape among urban landscape components, especially composing wide road's streetscape. First of all, this study made a simulation by deducing components of wide road's streetscape and controlling them with theoretical review of streetscape and consideration of wide road's local characteristic. With the evaluation on the base of them, that following four components could be the representative things of entrance part was confirmed by this study. They were familiar streetscape,symbolic scene as as an entrance gate, continuous and dynamic streetscape, and interesting and pleasant streetscape. And for the middle part, those four components could represent the wide road's streetscapeI were confirmed. They were familiar streetscape, safe and tender streetscape, pleasant and dynamic streetscape, and symbolic streetscape. It seems that the components of the streetscape obtained from the analysis of this study are utilized as reference data in the case of a future streetscape design conclusively.

• Journal of Korean Society of Forest Science
• /
• v.112 no.4
• /
• pp.544-553
• /
• 2023

The purpose of this study was to reveal the thermal comfort and physiological and psychological effects of spending time in broad-leaved forests in suumer. Thirty-one university students (with an average age of 21.4 ± 2.1 years) participated in the study, and a within-subjects experimental design methodology was used. The participants moved to an experimental site (with a crown closure of 76.6%) or a control site (25.9%), sat on a chair to eliminate the impact of movement, and rested for 5 minutes with closed eyes. At this time, thermal comfort, heart rate variability, heart rate, and forehead temperature were continuously measured. After that, blood pressure and pulse rate were measured, and a subjective evaluation was conducted. As a result, spending time at an experimental site showed a statistically significant decrease in the predicted mean vote and the percentage of dissatisfied values, enhancement of parasympathetic nerve activity, decrease of forehead temperature, diastolic blood pressure, heart rate, pulse rate, and improvement of personal thermal sensation (thermal sensation vote and comfort sensation vote). In conclusion, it was found that a forest with high crown closure reduces thermal stress and induces physiological and psychological relaxation.

• Journal of the Korean Society of Radiology
• /
• v.17 no.7
• /
• pp.1033-1039
• /
• 2023

Low-dose chest CT, which is used as a lung screening test, also includes information on coronary artery calcification within the scan range. The purpose of this study was to investigate the usefulness of determining coronary artery calcification using Low-dose chest CT. Those who underwent low-dose chest CT and coronary artery calcification score CT on the same day were eligible. Coronary artery calcium score CT results were divided into 4 groups (Low: 1〈CACS〈10, Mild: 10〈CACS〈100, Moderate: 100〈CACS〈400, High: 400〈CACS) by referring to the Coronary artery calcium score categories and risks. After selecting 30 people each group, five radiotechnologists with more than 15 years of experience in coronary artery calcium measurement retrospectively analyzed the presence or absence of coronary artery calcification in low-dose chest CT images. The results of the five observers' uniform interpretation of the low-dose chest CT image were consistent with the coronary artery calcium score CT results in Low group: 56%, Mild group: 96.6%, Moderate group: 100%, and High group: 100%. appeared. In the Low group, all 5 observers observed calcification in 17 out of 30 cases, and in 7 cases all 5 observers decided that calcification could not be identified. Coronary artery calcification could be observed in 100% of asymptomatic adults with a calcium score of 15 or higher in low-dose chest CT scans. The minimum calcium score that can be identified is 1, and it was found that even very small calcifications can be identified when the subject's body size is small or the scan is performed at a time when heart movement is minimal.

• Korean Journal of Radiology
• /
• v.22 no.11
• /
• pp.1841-1849
• /
• 2021

Objective: To prospectively investigate the feasibility of shear wave elastography (SWE) as a new quantitative and objective method for evaluating the stiffness of the gastrocnemius medialis (GM) muscle during passive stretching in patients with Parkinson's disease (PD). Materials and Methods: SWE of the GM muscle was performed in 28 patients with PD [13 female and 15 male; mean age ± standard deviation (SD): 63.0 ± 8.5 years] and 12 healthy controls (5 female and 7 male; mean age ± SD: 59.3 ± 6.4 years) during passive ankle rotation. A Young's modulus-ankle angle curve was constructed. The GM slack angle and baseline Young's modulus (E₀) were compared between the markedly symptomatic and mildly symptomatic sides of patients with PD, and healthy controls. Additionally, the correlation between the GM slack angle and the severity of rigidity, and the observer reproducibility of SWE in determining the GM slack angle were evaluated. Results: The GM slack angle was smaller on both the markedly and mildly symptomatic sides in patients with PD than in healthy controls (mean ± SD of -29.13° ± 3.79° and -25.65° ± 3.39°, respectively, vs. -21.22° ± 3.52°; p < 0.001 and p = 0.006, respectively). Additionally, in patients with PD, the GM slack angle on the markedly symptomatic side was smaller than that on the mildly symptomatic side (p = 0.003). The E0 value was lower on both the markedly and mildly symptomatic sides in patients with PD than in healthy controls (mean ± SD of 10.11 ± 2.85 kPa and 10.08 ± 1.88 kPa, respectively, vs. 12.23 ± 1.02 kPa; p = 0.012 and p < 0.001, respectively). However, no significant difference was found between the markedly and mildly symptomatic sides in patients with PD (p = 0.634). A negative linear relationship was observed between the GM slack angle and lower limb rigidity score on the markedly symptomatic side in patients with PD (r = -0.719; p < 0.001). The intraclass correlation coefficients for observer reproducibility of SWE ranged from 0.880 to 0.951. Conclusion: The slack angle determined by SWE may be a useful quantitative and reproducible method for evaluating muscle stiffness in patients with PD.

• Journal of the Korean earth science society
• /
• v.45 no.2
• /
• pp.111-120
• /
• 2024

Cloud coverage is a key factor in determining whether to proceed with observations. In the past, human judgment played an important role in weather evaluation for observations. However, the development of remote and robotic observation has diminished the role of human judgment. Moreover, it is not easy to evaluate weather conditions automatically because of the diverse cloud shapes and their rapid movement. In this paper, we present the development of a cloud monitoring program by applying a machine learning-based Python module "cloudynight" on all-sky camera images obtained at Miryang Arirang Astronomical Observatory (MAAO). The machine learning model was built by training 39,996 subregions divided from 1,212 images with altitude/azimuth angles and extracting 16 feature spaces. For our training model, the F1-score from the validation samples was 0.97, indicating good performance in identifying clouds in the all-sky image. As a result, this program calculates "Cloudiness" as the ratio of the number of total subregions to the number of subregions predicted to be covered by clouds. In the robotic observation, we set a policy that allows the telescope system to halt the observation when the "Cloudiness" exceeds 0.6 during the last 30 minutes. Following this policy, we found that there were no improper halts in the telescope system due to incorrect program decisions. We expect that robotic observation with the 0.7 m telescope at MAAO can be successfully operated using the cloud monitoring program.