• Korean Journal of Remote Sensing
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• v.40 no.4
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• pp.319-341
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• 2024

The utilization of multispectral imaging systems (MIS) in remote sensing has become crucial for large-scale agricultural operations, particularly for diagnosing plant health, monitoring crop growth, and estimating plant phenotypic traits through vegetation indices (VIs). However, environmental factors can significantly affect the accuracy of multispectral reflectance data, leading to potential errors in VIs and crop status assessments. This paper reviewed the complex interactions between environmental conditions and multispectral sensors emphasizing the importance of accounting for these factors to enhance the reliability of reflectance data in agricultural applications.An overview of the fundamentals of multispectral sensors and the operational principles behind vegetation index (VI) computation was reviewed. The review highlights the impact of environmental conditions, particularly solar zenith angle (SZA), on reflectance data quality. Higher SZA values increase cloud optical thickness and droplet concentration by 40-70%, affecting reflectance in the red (-0.01 to 0.02) and near-infrared (NIR) bands (-0.03 to 0.06), crucial for VI accuracy. An SZA of 45° is optimal for data collection, while atmospheric conditions, such as water vapor and aerosols, greatly influence reflectance data, affecting forest biomass estimates and agricultural assessments. During the COVID-19 lockdown,reduced atmospheric interference improved the accuracy of satellite image reflectance consistency. The NIR/Red edge ratio and water index emerged as the most stable indices, providing consistent measurements across different lighting conditions. Additionally, a simulated environment demonstrated that MIS surface reflectance can vary 10-20% with changes in aerosol optical thickness, 15-30% with water vapor levels, and up to 25% in NIR reflectance due to high wind speeds. Seasonal factors like temperature and humidity can cause up to a 15% change, highlighting the complexity of environmental impacts on remote sensing data. This review indicated the importance of precisely managing environmental factors to maintain the integrity of VIs calculations. Explaining the relationship between environmental variables and multispectral sensors offers valuable insights for optimizing the accuracy and reliability of remote sensing data in various agricultural applications.

• Journal of Navigation and Port Research
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• v.46 no.3
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• pp.251-258
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• 2022

Donghae Port is adjacently located to a residential area wherein 26,933 generations are creating a living environment. The areas comprise Song-jeong village (5,754 generations) and Bukp-yeong village (21,179 generations). Major cargoes handled in Donghae Port are dusty limestone, cement, anthracite, and bituminous coal, etc. In the process of handling such cargoes, air pollutants including oxide dust and fine dust which adversely impact the living conditions and health of residents are generated, causing air pollution in the vicinity of the port. Currently, Donghae Port is making an effort to improve the operation environment of the infrastructure and equipment in stages, for the purpose of reducing air pollutant emissions caused by the port industries in a long-term perspective. In this study, the sphere of influence of fine dust exposure and the degree of air pollution in the surrounding area were analyzed such as the state of fine dust concentration and diffusion in the vicinity of Donghae Port, fine dust diffusion pattern and spatial distribution of high-concentration considering wind direction and speed characteristics during the day and seasonal cycles. A more effective plan to reduce the concentration of fine dust in nearby areas by combining reduction plan, is being developed in terms of improvement regarding port infrastructure and equipment, and reduction measures considering the characteristics of the atmosphere environment according to the daytime, nighttime and season.

• Journal of the Korean Society of Clothing and Textiles
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• v.16 no.4 s.44
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• pp.405-416
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• 1992

This study was performed to investigate correlation between total body weight loss and local sweat rate and to find out any possible method that can estimate total body weight loss judging from local sweat rate. Twelve adult females were kept at 44 $\pm1^{\circ}C$, 50 ${\pm}5\%$ R.H. (1) Physiological responses such as total body weight loss, local sweat rate, rectal temperature, skin temperature, blood pressure and pulse, (2) micro climate inside garment and (3) subjective sensation were examined. Two types of garment such as long-sleeves with long pants (Type I) and half·sleeves with short pants (Type II) were used to observe the effect of garment types on sweating response. Both clothing weight was equal (132$\pm$3 g/$m^{2}$). The results were as follows: 1. Regardless of the different types, total body weight loss was more interrelated with the sweat rate on forehead than any other parts of the body. Except the forehead, different parts of body with different types of garment influenced on body weight loss quite differently. 2. Total body weight loss was more interrelated with the weight gain of garment than the local sweat rate. 3. Under the environment of 44$\pm1^{\circ}C,\;50{\pm}5\%$R.H., body weight loss during 1 hour of subject clothed and silted was 275.2 g/hr and weight loss per body surface area was 178.9 g/$m^{2}/hr$ Garment types have no influences on total body weight loss. 4. Local sweat rate (mg/7.07 $cm^{2}/hr$) was 208.0,191.0, 133.0, 115.0,81 0, 75.1 and 66.3 on scruff, breast, forehead, forearm, thigh, upper arm, leg respectively No evidence has been found that garment types influenced on local sweat rate (p<0.1). 5. No interrelationships between rectal temperature and total body weight loss, local skin temperature and total body weight loss, and local skin temperature and local sweat rate were found. From this study, some possible method that we can estimate total body' weight loss judging from weight loss of garment. But considering the fact that clothing design factor, the physical characteristics of fabric and environmental factor such as humidity and wind velocity should be concerned in weight loss of garment, it should be studied further whether the total body weight loss can be estimated properly from the weight loss of garment. This experiment suggest that different parts of body with different types of garment can influence on body weight loss quite differently. Therefore, in order to get more precise results, more studies under the diversity of garment types should be done in the near future.

• Journal of Environmental Health Sciences
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• v.46 no.5
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• pp.576-587
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• 2020

Objectives: This study calculated local residents exposures to VOCs (Volatile Organic Compounds) released into the atmosphere using the CalTOX model and carried out uncertainty analysis and sensitivity analysis. The model validity was analyzed by comparing the predicted and the actual atmospheric concentrations. Methods: Uncertainty was parsed by conducting a Monte Carlo simulation. Sensitivity was dissected with the regression (coefficients) method. The model validity was analyzed by applying r² (coefficient of determination), RMSE (root mean square error), and the Nash-Sutcliffe EI (efficiency index) formula. Results: Among the concentrations in the atmosphere in this study, benzene was the highest and the lifetime average daily dose of benzene and the average daily dose of xylene were high. In terms of the sensitivity analysis outcome, the source term to air, exposure time, indoors resting (ETri), exposure time, outdoors at home (ETao), yearly average wind speed (v_w), contaminated area in ㎡ (Area), active breathing rate (BRa), resting breathing rate (BRr), exposure time, and active indoors (ETai) were elicited as input variables having great influence upon this model. In consequence of inspecting the validity of the model, r² appeared to be a value close to 1 and RMSE appeared to be a value close to 0, but EI indicated unacceptable model efficiency. To supplement this value, the regression formula was derived for benzene with y=0.002+15.48x, ethylbenzene with y ≡ 0.001+57.240x, styrene with y=0.000+42.249x, toluene with y=0.004+91.588x, and xylene with y=0.000+0.007x. Conclusions: In consequence of inspecting the validity of the model, r² appeared to be a value close to 1 and RMSE appeared to be a value close to 0, but EI indicated unacceptable model efficiency. This will be able to be used as base data for securing the accuracy and reliability of the model.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.5
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• pp.151-159
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• 2017

The aspect of modern warfare is gradually changing to a network of warfare, and its central information electronic warfare is evolving every day. Recently, domestic equipment of electronic warfare, which have succeeded in domestic localization, are strongly influenced by the nature of the environment. Therefore, the structural reliability of the antenna switching module that connects the mast and antenna of the ES equipment is the most important. This study proposed a structure that has an improved structure of antenna switching module by currently analyzing the structure of the antenna switching module and the environmental influence. By modifying the structure of the antenna switching module welding method and part of the reinforcement block, the structure was improved and the validity of the improved antenna switching module was simulated using a load test. The simulation showed that the safety factors of antenna switching module welding point and reinforced block part was enhanced 5.3 and 1.5 times compared to the existing values. These values were verified by load (181kg) test results, which was each 3.7Mpa and 64.4Mpa. The load test results were similar to the simulation results and load supporting capacity of the proposed antenna switching module was enhanced.

• Korean Journal of Construction Engineering and Management
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• v.13 no.3
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• pp.67-77
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• 2012

O Having a highly reliable plan for the process and estimating an accurate construction period during the early stages of a construction project can prevent falsifying the plan and reduce the occurrence of construction delays. Moreover, it allows a succession of swift and accurate decisions to happen. The difficulty in obtaining an accurate estimate of the construction period is especially prominent in high-rise building projects because the works involved are very complicated and costly. As such, it is important that research is done to find out the impacts a reliable plan and good estimate of the construction period can bring with regards to the monthly work efficiency and success of a high-rise building project. However, due to the difference in climatic conditions at high altitude and surface level, the current way of calculating work efficiency in a typical project is inaccurate for a high-rise building project. With that, this paper aims to compute the work efficiency with height, taking into consideration the change in climatic elements at different working heights. A comparison of the results according to the climatic features of each city can also be done in this paper. According to the results calculated in work altitudes, the work efficiency in Busan falls the most. On the other hands, the work efficiency in Seoul falls the least. The reason these results are shown is the influence of wind speed at high altitude. The estimation of work efficiency at high altitude would be used for estimating construction period, feasibility studies, and selecting a city of high-rise building projects.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.2
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• pp.59-67
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• 2022

In this study, the monthly airborne chlorides flying into the offshore bridges were investigated depending on the sea level. The target structures were 9 bridges located on the western and southern coast of South Korea. The airborne chlorides were measured at different sea levels on each bridge every month during 1 year. The results showed that the strongest seasonal wind from the northwest in winter expecially have led increase of the airborne chlorides, and its effect was more significant in the western coast than the southern coast. It was also found that the airborne chlorides declined with the increase of sea level. Three types of curves were suggested for analyzing the decrease trend with the sea level, based on the airborne chlorides at the lowest measurement height of main tower. The trend was varied depending on the sea area, and even in the same sea area, the local topographic condition affected the airborne chlorides. It means that the location and local topography should be considered simultaneously for durability management in the framework of the chloride source, and then the influence of the chloride source should be classified, e.g. safe and dangerous. From these results, it is expected that it could be used as baseline data for the evaluation of the deterioration environment in the Detailed guidelines for safety and maintenance of facilities [Performance evaluation]_Bridge.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.5
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• pp.624-634
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• 1995

Tides at both of northern and southern entrances of Kamag Bay were compared by deploying tide gauges for 18 days during July-August 1994. To examine the response of the inner bay to the tidal waves through both entrances, a current meter was moored at the eastern pan of the inner bay. Current meter mooring failed at the northern entrance (Yosu) while the current data was collected for only 5 days at the southern site (Songdo). Maximum range was 357 and 352 cm at Yosu and Songdo, respectively. Respective amplitudes for M2, S2 Kl O1 tides of 95.5, 48.8, 20.5, 14.0cm at Yosu and 93.6, 47.2, 21.3, 13.1cm at Songdo yielded the form numbers of 0.23 and 0.24, respectively, both of which belong to the predominantly semidiurnal tide, Contributions from the overtides and compound tides were less than $4\%^ at both sites. Differences in Greenwich phase of major partial tides between two sites were negligible. Maximum speed of tidal current was about 100cm/sec at the southern entrance and about 40cm/sec at the inner bay. Residual current speed was 17cm/sec southwestward at the southern entrance and 0.9cm/sec southeastward at the inner bay. Temporal change in current at the inner bay showed that the wind had a significant influence upon the circulation in Kamag Bay.

• Journal of the Korean earth science society
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• v.38 no.6
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• pp.395-404
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• 2017

In this study, we classified observed fog events in the Middle Nakdong River near Gumi and analyzed the meteorological characteristics before and after the fog formation. The observation was performed from 2013 to 2015 using visibility meter. A total of 74 fog events were observed and most of them were classified as steam fog. The duration of observed steam fogs was longer than that of typical inland fogs because the nocturnal evaporation from the water surface was enhanced by the topographical characteristics. In order to analyze the effect of evaporation from the stream on the fog duration, the evaporation was estimated using the Penman-Monteith and the Bulk aerodynamic methods. The estimated evaporation by the Bulk method was similar to the actual evaporation from the water surface. Therefore, the Bulk method is suitable for estimating the evaporation from water surface. The evaporation amount, estimated by using the Bulk method was higher on fog days than non-fog days at 06 LST and 07 LST. The added evaporation of fog days released latent heat to the atmosphere and provided energy to maintain the turbulence in the fog. This phenomenon was confirmed by the increase of wind speed, temperature and turbulent kinetic energy within the fog.

• Journal of the Korean Society of Radiology
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• v.12 no.6
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• pp.719-725
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• 2018

After 9/11 attacks in the U.S, Terrorism has increased the number of unspecified casualties through multi-use facility terror attacks compared to the past. The subsequent London bombings and the self-destruction of Pakistan increased people's fear and social anxiety. As international events have been held in Korea recently, awareness and concern over radioactive terrorism and security management of radioactive materials are increasing. In this paper, we compared the results of different meteorological conditions using HotSpot Code. After creating a possible terror scenario in Korea, sources likely to be use in RDD and Dirty bomb were investigated. The meteorological condition was selected by comparing the Pasquill-Gifford stability class with the most stable condition F and the most unstable condition A. The result value of the A and F condition through simulation were shown not to cause citizens to die from acute effects due to radiological effects. The range of radioactivity is different according to the wind speed and the meteorological stability, and the degree of radioactivity dilution is different according to meteorological conditions. Analysis results are expected to be used for initial response in the event of a radioactive terrorist attack.