• Tunnel and Underground Space
• /
• v.34 no.3
• /
• pp.208-217
• /
• 2024

There is so much research effort for developing and implementing deep learning-based surveillance systems to manage health and safety issues in construction sites. Especially, the development of deep learning-based object detection in various environmental changes has been progressing because those affect decreasing searching performance of the model. Among the various environmental variables, the accuracy of the object detection model is significantly dropped under low illuminance, and consistent object detection accuracy cannot be secured even the model is trained using low-light images. Accordingly, there is a need of low-light enhancement to keep the performance under low illuminance. Therefore, this paper conducts a comparative study of various deep learning-based low-light image enhancement models (GLADNet, KinD, LLFlow, Zero-DCE) using the acquired construction site image data. The low-light enhanced image was visually verified, and it was quantitatively analyzed by adopting image quality evaluation metrics such as PSNR, SSIM, Delta-E. As a result of the experiment, the low-light image enhancement performance of GLADNet showed excellent results in quantitative and qualitative evaluation, and it was analyzed to be suitable as a low-light image enhancement model. If the low-light image enhancement technique is applied as an image preprocessing to the deep learning-based object detection model in the future, it is expected to secure consistent object detection performance in a low-light environment.

• The Journal of Engineering Geology
• /
• v.34 no.1
• /
• pp.39-49
• /
• 2024

The construction of underground infrastructure is garnering growing increasing research attention owing to population concentration and infrastructure overcrowding in urban areas. An important associated task is establishing a monitoring system to evaluate stability during infrastructure construction and operation, which relies on developing techniques for ground investigation that can evaluate ground stability, verify design validity, predict risk, facilitate safe operation management, and reduce construction costs. The method proposed here uses satellite imaging in a cost-effective and accurate ground investigation technique that can be applied over a wide area during the construction and operation of infrastructure. In this study, analysis was performed using Synthetic Aperture Radar (SAR) data with the time-series radar interferometric technique to observe surface displacement during the construction of urban underground roads. As a result, it was confirmed that continuous surface displacement was occurring at some locations. In the future, comparing and analyzing on-site measurement data with the points of interest would aid in confirming whether displacement occurs due to tunnel excavation and assist in estimating the extent of excavation impact zones.

• Journal of Korea Water Resources Association
• /
• v.57 no.6
• /
• pp.409-419
• /
• 2024

Climate change is already impacting sustainable water resource management. The influence of climate change on water supply from reservoirs has been generally assessed using climate change scenarios generated based on global climate models. However, inherent uncertainties exist due to the limitations of estimating climate change by assuming IPCC carbon emission scenarios. The decision scaling approach was applied to mitigate these issues in this study focusing on four reservoir watersheds: Chungju, Yongdam, Hapcheon, and Seomjingang reservoirs. The reservoir water supply reliablity was analyzed by combining the rainfall-runoff model (IHACRES) and the reservoir operation model based on HEC-ResSim. Water supply reliability analysis was aimed at ensuring the stable operation of dams, and its results ccould be utilized to develop either structural or non-structural water supply plans. Therefore, in this study, we aimed to assess potential risks that might arise during the operation of reserviors under various climate conditions. Using observed precipitation and temperature from 1995 to 2014, 49 climate stress scenarios were developed (7 precipitation scenarios based on quantiles and 7 temperature scenarios ranging from 0℃ to 6℃ at 1℃ intervals). Our study demonstrated that despite an increase in flood season precipitation leading to an increase in reservoir discharge, it had a greater impact on sustainable water management compared to the increase in non-flood season precipitation. Furthermore, in scenarios combining rainfall and temperature, the reliability of reservoir water supply showed greater variations than the sum of individual reliability changes in rainfall and temperature scenarios. This difference was attributed to the opposing effects of decreased and increased precipitation, each causing limitations in water and energy-limited evapotranspiration. These results were expected to enhance the efficiency of reservoir operation.

• Korean Journal of Remote Sensing
• /
• v.38 no.6_3
• /
• pp.1827-1836
• /
• 2022

Disasters that occur unexpectedly are difficult to predict. In addition, the scale and damage are increasing compared to the past. Sometimes one disaster can develop into another disaster. Among the four stages of disaster management, search and rescue are carried out in the response stage when an emergency occurs. Therefore, personnel such as firefighters who are put into the scene are put in at a lot of risk. In this respect, in the initial response process at the disaster site, robots are a technology with high potential to reduce damage to human life and property. In addition, Light Detection And Ranging (LiDAR) can acquire a relatively wide range of 3D information using a laser. Due to its high accuracy and precision, it is a very useful sensor when considering the characteristics of a disaster site. Therefore, in this study, development and experiments were conducted so that the robot could perform real-time monitoring at the disaster site. Multi-sensor module was developed by combining LiDAR, Inertial Measurement Unit (IMU) sensor, and computing board. Then, this module was mounted on the robot, and a customized Simultaneous Localization and Mapping (SLAM) algorithm was developed. A method for stably mounting a multi-sensor module to a robot to maintain optimal accuracy at disaster sites was studied. And to check the performance of the module, SLAM was tested inside the disaster building, and various SLAM algorithms and distance comparisons were performed. As a result, PackSLAM developed in this study showed lower error compared to other algorithms, showing the possibility of application in disaster sites. In the future, in order to further enhance usability at disaster sites, various experiments will be conducted by establishing a rough terrain environment with many obstacles.

• Journal of the Korean Society of Radiology
• /
• v.11 no.1
• /
• pp.9-17
• /
• 2017

A high degree of precision and accuracy in Gamma Knife Radiosurgery(GKRS) is a fundamental requirement for therapeutical success. Elaborate radiation delivery and dose gradients with the steep fall-off of radiation are clinically applied thus necessitating a dedicated Quality Assurance(QA) program in order to guarantee dosimetric and geometric accuracy and reduce all the risk factors that can occur in GKRS. In this study, as a part of QA we verified the accuracy of single-shot dose profiles used in the algorithm of Gamma Knife Perfexion(PFX) treatment planning system employing Variable Ellipsoid Modeling Technique(VEMT). We evaluated the dose distributions of single-shots in a spherical ABC phantom with diameter 160 mm on Gamma Knife PFX. The single-shots were directed to the center of ABC phantom. Collimating configurations of 4, 8, and 16 mm sizes along x, y, and z axes were studied. Gamma Knife PFX treatment planning system being used in GKRS is called Leksell GammaPlan(LGP) ver 10.1.1. From the verification like this, the accuracy of GKRS will be doubled. Then the clinical application must be finally performed based on precision and accuracy of GKRS. Specifically the width at the 50% isodose level, that is, Full-Width-of-Half-Maximum(FWHM) was verified under such conditions that a patient's head is simulated as a sphere with diameter 160mm. All the data about dose profiles along x, y, and z axes predicted through VEMT were excellently consistent with dose profiles from LGP within specifications(${\leq}1mm$ at 50% isodose level) except for a little difference of FWHM and PENUMBRA(isodose level: 20%~80%) along z axis for 4 mm and 8mm collimating configurations. The maximum discrepancy of FWHM was less than 2.3% at all collimating configurations. The maximum discrepancy of PENUMBRA was given for the 8 mm collimator along z axis. The difference of FWHM and PENUMBRA in the dose distributions obtained with VEMT and LGP is too small to give the clinical significance in GKRS. The results of this study are considered as a reference for medical physicists involved in GKRS in the whole world. Therefore we can work to confirm the validity of dose distributions for all collimating configurations determined through the regular preventative maintenance program using the independent verification method VEMT for the results of LGP and clinically assure the perfect treatment for patients of GKRS. Thus the use of VEMT is expected that it will be a part of QA that can verify and operate the system safely.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.41 no.10
• /
• pp.1475-1485
• /
• 2012

This study was conducted in order to understand nutrition teachers (dietitians)' perceptions of barriers to implementation of HACCP system in school foodservices in Gyeongnam, Korea. Questionnaires were distributed to 350 nutrition teachers (dietitians) from November to December of 2009, and 214 were collected and analyzed. The results of this study were as follows. First, nutrition teachers (dietitians) recognized the following as barriers in implementing the HACCP system: 'the status of facilities and utilities'> 'monitoring'> 'work satisfaction'> 'foodservice employees'> 'cooperation of HACCP team'> 'cooperation of persons concerned besides foodservice employees'> 'understanding the HACCP system'. Second, total working experience was found to be the factor most affecting 'cooperation of HACCP team (p<0.01)', 'cooperation of persons concerned besides foodservice employees (p<0.01)', 'foodservice employees (p<0.05)', and 'work satisfaction (p<0.05)'. Further, 'the status of facilities and utilities' was significantly affected by 'construction/reconstruction of kitchen (p<0.01)', 'division of kitchen area (p<0.01)', 'existence of preliminary preparation room (p<0.01)', and 'existence of dishwashing room (p<0.01)'. Third, dietitians perceived the following concerning hindrance factors of the HACCP system according to CCP stage: 'CCP 1'> 'CCP 3'> 'CCP 2, 'CCP 6'> 'CCP 4'> 'CCP 8'> 'CCP 7'> 'CCP 5'. In conclusion, this study showed that nutrition teachers (dietitians) in the Gyeongnam area recognized 'the status of facilities and utilities' from HACCP areas and 'CCP 1 (menu planning)' from CCP stages as the greatest barriers to implementing the HACCP system in school foodservices. To implement the HACCP system successfully in school foodservices, facilities and utilities should be properly equipped, and menu planning training for nutrition teachers (dietitian) should be conducted.

• The Korean Journal of Air & Space Law and Policy
• /
• v.33 no.2
• /
• pp.3-34
• /
• 2018

Korea's air transport industry has a 70-year history since Korea National Airline was establishment in October 1948. Korea has 9 airlines which have international air transport business licenses, and as of 2017, air transport performance(Domestic & International) is ranked 8th in the world. Through analysis of Korea's air transport industry, this paper examines the essential problems of the domestic air transport industry and what policies and laws should be supplemented, and presents an "Policy Directions for the Air Transport Industry" that can continue to grow into a global aviation leading country in the future. Analysis of aviation statistics shows that the nation's air transport industry has a very high growth rate, and national airlines continue to invest in sustainable growth. Furthermore, new companies are also trying to enter the market. As of November 2018, four companies applied for licenses for international air transport business, one for international air transport business (cargo) license, and the Ministry of Land, Infrastructure and Transport is expected to decide whether to issue the license by first quarter of 2019. While some expect price reductions and consumer benefits through competition promotion, others worry about worsening airline financial structures and reducing safety investment due to competition. To sum up the problems of the nation's air transport industry, first, low-cost airlines focus only on attracting domestic demand, and thus have a weak foundation for continued growth. Second, the rapid growth in recent years has led to the lack of aviation professionals such as pilots and technicians and the saturation of slots at major airports. Third, since the financial soundness of airlines is not systematically managed, the financial situation of airlines can quickly deteriorate and the damage can be attributed to consumers. In order for the national airlines to continue to develop, the first is to focus on the endless demand of the global aviation market and to secure international competitiveness. Second, the government should support the airline infrastructure according to the size of the air transport industry, third, we will systematically nurture aviation experts who will lead the future of the nation's air transport industry, and finally, the government will have to continuously manage the financial status of airlines to prevent consumer damage in advance. Nowadays the air transport industry has become very competitive. Not only do airlines have to work hard for the sustainable development of national airlines, but all government agencies must support our airline companies in policy to win international competition.

• The Korean Journal of Nuclear Medicine Technology
• /
• v.14 no.2
• /
• pp.65-76
• /
• 2010

Purpose: he use of PET scanners and the number of patient in Korea have been increased for recent several years dramatically. For this reason, technologists have more possibilities to be exposed to the radiation. The hospitals using PET scanners should make an effort to reduce the radiation exposure dose. The purpose of this study was to evaluate the radiation exposure does when using radiation shielding devices. The evaluation was performed through questionnaire survey and experiment. Materials and Methods: First, the technologists who had experience working in PET center in 2008-2009 were surveyed with questionnaire and TLD Figures, personal opinion of utilization of radiation shielding devices are analyzed. Second, we measured the shielding rate of shielding devices which have been using in PET study procedures. We divided the procedures into four steps; distribution, moving, injection of $^{18}F$-FDG and patient setup. Results: First, the results of this survey, using of L-block+Syringe shield, L-block, Syringe shield, No shield during the injection, were each 58.5%, 20%, 9%, 12.3%. The TLD values according to utilization of radiation shield, using both L-block+Syringe Shield and L-block showed the lower TLD values, and Syringe shield only or No shield showed the higher TLD values. Second, the results of experiments according to PET study procedures measured the shielding rates as follows. The shielding rates during the distribution using L-block, L-block+Apron shield were measured 97.4%, 97.7%. The shielding rates during the $^{18}F$-FDG delivery to the injection room using mobile Syringe shield, Syringe holder, Syringe shield carrier were each 81.7%, 98.9%, 99.7%. The shielding rates during the injection using Syringe shield, L-block, L-block+Syringe shield were measured each 51.9%, 98.3%, 98.7%. The shielding rates of Apron were measured in each 30, 60, 90, 120, 150 cm distance. The measurement were each 16.9%, 14.2%, 16.6%, 17.1%, 18.1%, 18.6%. Conclusion: The most effective method for radiation shielding is to using L-block during the $^{18}F$-FDG distribution and Syringe shield carrier during in moving $^{18}F$-FDG. For the $^{18}F$-FDG injection, L-block+Syringe shield have to be used. The shielding effect of Apron has shown average 16.4%. According to the survey of questionnaire, the operators recognized well risk of the radiation exposure but, tended ignore in working. The radiation dose according to recognition of radiation exposure risk was not relevant. but radiation dose according to utilization of radiation shield lower the more use it. The main reason of no use of shielding devices is cumbersome, 55% of the respondents answered. I'm sure, by use of radiation shield in all PET procedure, radiation exposure will be reduced considerably.

• Korean Journal of Soil Science and Fertilizer
• /
• v.45 no.4
• /
• pp.555-559
• /
• 2012

Manures contain a variety of pathogenic microorganisms that pose a risk to human or animal. On-farm contaminations through contaminated manure were considered likely sources of the pathogen for several outbreak. Pathogenic microorganisms may survive in low numbers during the composting process and subsequently regrow to high levels under favorable conditions. The objective of this study was to investigate effect of temperature on survival of Salmonella enterica and Staphylococcus aureus in livestock manure compost. Commercial livestock manure compost (manure 60%, sawdust 40%) was inoculated with S. enterica and S. aureus. Compost was incubated at four different temperatures (10, 25, 35, and $55^{\circ}C$) for 20 weeks. Samples were taken every week during incubation depending on the given conditions. S. enterica persisted for up to 1 day in livestock manure compost at $55^{\circ}C$, over 140 days at $10^{\circ}C$, 140 days at $25^{\circ}C$, and 70 days at $35^{\circ}C$, respectively. S. aureus persisted for up to 1 day in livestock manure compost at $55^{\circ}C$ and 90 days at $10^{\circ}C$, 70 days at $25^{\circ}C$, and 40 days at $35^{\circ}C$, respectively. The results indicate that S. enterica and S. aureus persisted longer under low temperature condition. S. enterica survived longer than S. aureus at three different temperatures (10, 25, and $35^{\circ}C$). This study will provide useful and practical guidelines to applicators of soil in deciding appropriate handling and time frames for land application of livestock manure compost for sustainable agriculture. Results from these studies provide useful information in identifying manure handling practices to reduce the risk of S. enterica and S. aureus transmission to fresh produce.

• The Korean Journal of Pesticide Science
• /
• v.19 no.4
• /
• pp.354-360
• /
• 2015

In recent years, Allium victorialis has been extensively used as a pharmacological agent for various diseases in the form of anti-arteriosclerotic, anti-diabetic and anti-cancer. Allium victorialis is severely affected by various fungal diseases since it naturally grow in the shady and humid environments in Korea. In this case, different types of fungicides are applied to control the fungal diseases in Allium victorialis. The present study was aimed to determine the residual characteristics of two fungicides namely tebuconazole and fludioxonil on Allium victorialis. For this study, the fungicides were drenched soil on Allium victorialis in the cultivation area Pyeongchang by the standard (two thousand fold) and double (thousand fold) dilutions. At the end of $15^{th}$, $30^{th}$ and $40^{th}$ days samples were collected for residue analysis. Residues of tebuconazole and fludioxonil were analyzed using GC/NPD (Gas Chromatography/Nitrogen Phosphorus Detector) and their recovery were found to be 108.8~119.5% and 91.3~104.8%, respectively. The method of limits of quantification for both fungicides was $0.01mg\;kg^{-1}$. Further, the results of this study shows that the residue levels of both fungicides on Allium victorialis were <$0.01{\sim}0.12mg\;kg^{-1}$ and $0.01{\sim}0.09mg\;kg^{-1}$ and their % ADI (% Acceptable Daily Intake) were 17.44% and 25.75%, respectively. Based on the results obtained in this study, we suggest that the residue levels of both of the fungicides on Allium victorialis are safe and these fungicides can also be used to control fungal diseases in Allium victorialis.