• Journal of the Korea Computer Graphics Society
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• v.27 no.5
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• pp.63-71
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• 2021

Among drone autonomous flight technologies, obstacle avoidance is a very important technology that can prevent damage to drones or surrounding environments and prevent danger. Although the LiDAR sensor-based obstacle avoidance method shows relatively high accuracy and is widely used in recent studies, it has disadvantages of high unit price and limited processing capacity for visual information. Therefore, this paper proposes an obstacle avoidance algorithm for drones using camera-based PPO(Proximal Policy Optimization) reinforcement learning, which is relatively inexpensive and highly scalable using visual information. Drone, obstacles, target points, etc. are randomly located in a learning environment in the three-dimensional space, stereo images are obtained using a Unity camera, and then YOLov4Tiny object detection is performed. Next, the distance between the drone and the detected object is measured through triangulation of the stereo camera. Based on this distance, the presence or absence of obstacles is determined. Penalties are set if they are obstacles and rewards are given if they are target points. The experimennt of this method shows that a camera-based obstacle avoidance algorithm can be a sufficiently similar level of accuracy and average target point arrival time compared to a LiDAR-based obstacle avoidance algorithm, so it is highly likely to be used.

• Korean Journal of Plant Resources
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• v.35 no.2
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• pp.362-371
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• 2022

This study was conducted to analyze the fragrance characteristics of Cymbidium 'Saelbit' and 'Midan' according to floral organs. As test materials, full bloom flowers were divided into four organs: sepal, petal, labellum, and column. Using the gas chromatography (GC) based electronic nose, fragrance patterns, intensity, and volatile components were analyzed. Principle component analysis (PCA) and discriminant factorial analysis (DFA) plots by electronic nose data showed that volatiles of both cultivars have a distinct difference in fragrance patterns according to the floral organs, and the value of fragrance distance and pattern discrimination index (PDI) between samples was significantly high between control and sepals in both cultivars. Among the main fragrance components, several components including nootkatone were detected in both cultivars and all floral organs. However, few components such as decane were found in specific cultivar or floral organs. These results will provide useful information to select suitable materials with desired fragrance and to enhance the utilization of domestic Cymbidium cultivars. In addition, considering the recent negative perception of artificial ingredients and the growing demand for natural materials, continuous researches on scent properties of promising cultivars are required.

• Korean Journal of Plant Resources
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• v.35 no.2
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• pp.183-191
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• 2022

Ginseng (Panax ginseng C.A. Meyer) is a perennial plant and propagates by seeds, and those need after-ripening for germination. To be ready for climate change and to ensure a stable seed supply, the technique for storing seeds in short-term and long-term in large quantities is required. In this study, dehisced ginseng seeds from two locations, batch #1 and batch #2, were stored at -3.5℃ with different moisture content, and after 3, 15, and 27 months of storage, the percentage of radicle emergence and shoot emergence were measured. After 3 months, radicle emergence and shoot emergence were normal only when the seed moisture content was more than 35%, and overall, germination was higher in batch #2 than in batch #1. After 15 months, the partially dehydrated seeds, with a moisture content between 45 to 54%, showed the highest germination rates, and most of the undried seeds were spoiled and failed to germinate. Seeds with moisture content lower than 25% had poor germination, too. The partially dehydrated seeds also succeeded in germination and growth in the soil after 15 months of storage, but deteriorated after one more 1 year, too. In summary, ginseng seeds look like have temperate recalcitrant seed characteristics, and partial dehydration allows extension of seed longevity.

• Korean Journal of Remote Sensing
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• v.38 no.6_3
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• pp.1749-1760
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• 2022

In modern society, human and social damages caused by natural disasters and frequent disaster accidents have been increased year by year. Prompt access to dangerous disaster sites that are inaccessible or inaccessible using state-of-the-art Earth observation equipment such as satellites, drones, and survey robots, and timely collection and analysis of meaningful disaster information. It can play an important role in protecting people's property and life throughout the entire disaster management cycle, such as responding to disaster sites and establishing mid-to long-term recovery plans. This special issue introduces the National Disaster Management Research Institute (NDMI)'s disaster management technology that utilizes various Earth observation platforms, such as mobile survey vehicles equipped with close-range disaster site survey sensors, drones, and survey robots, as well as satellite technology, which is a tool of remote earth observation. Major research achievements include detection of damage from water disasters using Google Earth Engine, mid- and long-term time series observation, detection of reservoir water bodies using Sentinel-1 Synthetic Aperture Radar (SAR) images and artificial intelligence, analysis of resident movement patterns in case of forest fire disasters, and data analysis of disaster safety research. Efficient integrated management and utilization plan research results are summarized. In addition, research results on scientific investigation activities on the causes of disasters using drones and survey robots during the investigation of inaccessible and dangerous disaster sites were described.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.5
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• pp.443-452
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• 2021

College students face serious difficulties while seeking jobs, leading to a high degree of stress, which is thought to affect their attitude towards smoking. The purpose of this study was to identify the relationship between hardiness, job-seeking stress, and the attitude towards smoking among students, and to further identify the factors influencing smoking attitude. Data were collected using a structured questionnaire administered to 145 students. Data analysis was performed using the SPSS program, t-test, ANOVA, Kruskal Wallis test, Pearson's Correlation Coefficients, and hierarchical multiple regression analysis. Smokers constituted 22.1% of the sample. The study showed that smoking attitudes varied according to the smoking status (H=28.26, p<.001). The smoking attitude was seen to be desirable in the high group (t=-3.27, p=.001) and low job-seeking stress group (t=4.40, p<.001). There was a positive correlation between hardiness and smoking attitude (r=.18, p=.028). There was a negative correlation between job-seeking stress and smoking attitude (r=-.28, p=.001). Also, the factors affecting the smoking attitude were non-smoker respondent (β=.50, p<.001), job-seeking stress (β=-.23, p=.015), former smoker respondent (β=.22, p=.016) and the explanatory power was 24.3%. Therefore, school and health public center counseling and employment support programs need to help students manage and cope with stressful situations to change their attitude towards smoking in a desirable direction.

• Journal of Conservation Science
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• v.36 no.6
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• pp.541-548
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• 2020

There is a growing demand for natural materials to replace adhesives based on volatile organic compounds (VOCs). However, the exclusion of VOCs from the manufacturing process leads to difficulties in manufacturing, and reduction in productivity and preservability. In this paper, we report the manufacture of natural bioadhesives using the carrageenan component of seaweed. λ-carrageenan, isolated from the extracted total carrageenan, was used to prepare a highly stable adhesive for paper. The resulting composition was 52.0 ± 1.0% λ-carrageenan, 30.5 ± 0.5% Polyvinylpyrrolidone, 1.0 ± 0.05% ethylhexylglycerin, 1.5 ± 0.05% glycerin, 13.5 ± 0.5% dextrine, and 0.6 ± 0.05% food-grade antifoam emulsion. The viscosity was found to be 1.13 ± 0.07 × 105 cP (25℃), UV degradation occurred at pH6.22, drying rate was 15min, △b^* was -10.79, and △E^* ab was 8.18. The bioadhesive showed an excellent adhesion strength of 44.63 kgf/cm². Thus this adhesive showed excellent fungal resistance and good adhesive persistence, without the presence of total volatile organic compounds (TVOC), formaldehyde (HCHO), and heavy metals.

• Korean Journal of Ichthyology
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• v.33 no.2
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• pp.57-63
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• 2021

This study was carried out to clarify the egg, larvae and juveniles development of Carassius cuvieri in Nakdong River, Gyeongbuk. The amount of spawning of female C. cuvieri was about 30,400~44,900 (average 37,650±7,250). The egg shape was circular and the size was 1.24~1.37 mm (average 1.31±0.04 mm, n=30). At 100 hours after fertilization, more than of the total embryos were hatched. The newly hatched larvae had an 4.69~5.65 mm in total length (average 5.15±0.31 mm, n=10) and had egg yolk in the abdomen. At 3 days after hatching, the preflexion larvae absorbed all egg yolk was 6.27~6.70 mm in total length (average 6.59±0.08 mm, n=10). On the 10 days after hatching, the postflexion larvae were 8.71~8.92 mm in total length (average 8.81±0.07 mm, n=10), and the tip of the caudal fin was bent at 45°. On the 42 days after hatching, the total length of 15.1~16.8 mm (average 15.8±0.57 mm, n=10) was transferred to juvenile as the number of fins was (iii17 dorsal fins, iii4 anal fins) reached a constant number of each part.

• Korean Journal of Ichthyology
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• v.32 no.4
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• pp.222-231
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• 2020

The egg development and early life history of Sharpbelly Hemiculter leucisculus were investigated. For the experiments, the mature adults were collected at the Lake Yedang in Korea. The eggs from the females were obtained by injecting 10 IU/g of human chorionic gonadotropin and inseminated by wet method in the laboratory. The fertilized eggs were 0.97±0.02 mm (0.9~1.0 mm n=30) in diameter. The embryo began to hatch about 32 hrs after fertilization under water temperature of 22±1℃. The newly-hatched larvae were 3.0±0.2 mm (2.6~3.4 mm, n=15) in total length, and they haven't Melanophore. Six days after hatching, the Preflexion larva were 5.7±0.1 mm (5.4~5.8 mm, n=15) in total length, and they began to eat a Rotifer. 17 days after hatching, the Flexion larva were 6.8±0.2 mm (6.5~7.0 mm, n=15) in total length, and a gas bladder develop above the intestine. 30 days after hatching, the Postflexion larva were 8.8±0.7 mm (7.9~10.3 mm, n=15) in total length, three dorsal fin rays began to develop in the membrane fins. 50 days after hatching, the Juvenile were 20.8±0.8 mm (18.8~24.6 mm, n=15) in total length, and all their fin-rays were formed.

• Journal of the Korea Convergence Society
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• v.12 no.7
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• pp.273-282
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• 2021

Nursing home plays a role in providing elderly care in the context of China's rapid population aging, but little understanding of the efficiency of the nursing homes. In this paper, we investigated the efficiency in nursing homes using Data Envelopment Analysis (DEA) and Malmquist index (MPI) for the modeling of the number of nursing home beds, fixed assets, and medical personnel as input variables, and the number of elderly people of self-care, the number of elderly people of partial self-care, the number of bed-ridden elderly people and the income of nursing homes as output variables. Stratification analysis showed that the top two provinces in the DEA-CCR yield were Beijing and Shanghai in the five-year survey period. Four provinces (Beijing, Jiangsu, Shandong, and Shanghai) scored 1.00 in terms of DEA-BCC yield. The MPI analysis showed that Hainan ranked the highest five-year average in the included provinces. In terms of resource utilization, internal management, operation scale, and other aspects, the nursing homes in the provinces with high-efficiency evaluation results show high efficiency and technological progress, whereas the areas with low-efficiency evaluation showed a feature of the improving technical efficiency.

• Journal of the Korean Association of Geographic Information Studies
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• v.25 no.4
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• pp.107-118
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• 2022

As connected and automated driving(CAD) technology is entering its commercialization stage, service platforms providing CAD-based mobility services have increased these days. However, CAD-baded mobility services with these platforms need more consideration for the demand for mobility services when determining target areas for CAD-based mobility services because current CAB-based mobility design focus on driving performance and driving stability. For a more efficient design of CAD-based mobility services, we analyzed the applicability for the introduction of CAD-based mobility services in terms of driving difficulty of CAD and demand patterns of current non-CAD based-mobility services, e.g., taxi, demand-responsive transit(DRT), and special transportation systems(STS). In addition, for the spatial analysis of the applicability of the CAD-based mobility service, we propose the Index for Autonomous Driving Applicability (IADA) and analyze the characteristics of the spatial distribution of IADA from the network perspective. The analysis results show that the applicability of CAD-based mobility services depends more on the demand patterns than the driving difficulty of CAV. In particular, the results show that the concentration pattern of demand in a specific road link is more important than the size of demand. As a result, STS service shows higher applicability compared to other mobility services, even though the size of demand for this mobility service is relatively small.