• Journal of Environmental Impact Assessment
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• v.32 no.6
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• pp.577-589
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• 2023

In Korea, the technical techniques for assessing visual impacts are standardized, but the methods for assessing the marine landscape itself are not standardized and need to be improved. In particular, in the landscape impact assessment of offshore wind power generation in Korea, it is necessary to recognize the landscape itself as a receptor and prepare a system that can evaluate the characteristics and sensitivity of the landscape. In this study, we propose an evaluation method for preparing a marine landscape quality assessment document that reflects the project characteristics of offshore wind power projects, and examine the possibility of utilization by applying it to actual project sites as an example. To evaluate the quality of marine scenery in offshore wind power projects, evaluation items of landscape characteristics, physical characteristics, and socio-cultural characteristics were evaluated based on the preliminary survey contents, and the quality of marine scenery was divided into five grades. Next, the evaluation criteria of the evaluation items were synthesized and the quality of the marine landscape was classified into preservation grade (grade 5), semi-preservation grade (grade 4), buffer grade (grade 3), semi-improvement grade (grade 2), and improvement grade (grade 1). In addition, the Sinan-Ui Offshore Wind Farm, an actual project site, was randomly selected to conduct the evaluation process and examine its utilization. This study aims to complement the existing method of visual impact assessment in offshore wind power projects and evaluate the quality of the marine landscape itself to effectively conserve marine landscape resources during offshore wind power projects. Rather than relying on mechanical and quantitative evaluation, this study is expected to be used as a basis for comprehensive understanding of the location and socio-cultural characteristics of the project site and for communication and cooperation with stakeholders.

• Korean Journal of Remote Sensing
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• v.39 no.5_3
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• pp.933-948
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• 2023

Atmospheric aerosols not only have adverse effects on human health but also exert direct and indirect impacts on the climate system. Consequently, it is imperative to comprehend the characteristics and spatiotemporal distribution of aerosols. Numerous research endeavors have been undertaken to monitor aerosols, predominantly through the retrieval of aerosol optical depth (AOD) via satellite-based observations. Nonetheless, this approach primarily relies on a look-up table-based inversion algorithm, characterized by computationally intensive operations and associated uncertainties. In this study, a novel high-resolution AOD direct retrieval algorithm, leveraging machine learning, was developed using top-of-atmosphere reflectance data derived from the Geostationary Ocean Color Imager-II (GOCI-II), in conjunction with their differences from the past 30-day minimum reflectance, and meteorological variables from numerical models. The Light Gradient Boosting Machine (LGBM) technique was harnessed, and the resultant estimates underwent rigorous validation encompassing random, temporal, and spatial N-fold cross-validation (CV) using ground-based observation data from Aerosol Robotic Network (AERONET) AOD. The three CV results consistently demonstrated robust performance, yielding R²=0.70-0.80, RMSE=0.08-0.09, and within the expected error (EE) of 75.2-85.1%. The Shapley Additive exPlanations(SHAP) analysis confirmed the substantial influence of reflectance-related variables on AOD estimation. A comprehensive examination of the spatiotemporal distribution of AOD in Seoul and Ulsan revealed that the developed LGBM model yielded results that are in close concordance with AERONET AOD over time, thereby confirming its suitability for AOD retrieval at high spatiotemporal resolution (i.e., hourly, 250 m). Furthermore, upon comparing data coverage, it was ascertained that the LGBM model enhanced data retrieval frequency by approximately 8.8% in comparison to the GOCI-II L2 AOD products, ameliorating issues associated with excessive masking over very illuminated surfaces that are often encountered in physics-based AOD retrieval processes.

• Asian Journal of Atmospheric Environment
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• v.7 no.2
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• pp.120-128
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• 2013

The concentration and composition of particulate matter (PM) in the atmosphere can directly reflect the environmental pollution. The atmospheric pollution in some Cameroonian cities is increasing with the industrial development and urbanization. Air pollution is inherently complex, containing PM of varied size and composition. This PM exists as a dynamic cloud interacting with sunlight and is modified by the meteorology. The reflectometer and the EDXRF spectrometry are applied to determine the concentration of some specific elements at four sites in the city of Yaound$\acute{e}$. The particular aim of the present work is to put in place data base on air pollution in urban area and elaborate regulations on the emissions issued to industrial and vehicle activities. This study provides an overview of the concentration of black carbon and some specific elements in the air, which have impacts on human health. The measurement was done by distinguishing the size of particle. So that, the particle with aerodynamic diameter between $2.5-10{\mu}m$ (so-called coarse particle) and aerodynamic diameter < $2.5{\mu}m$ (so-called fine particle) were considered to obtain more information about levels of the inhalable fraction of the location. The results obtained in four locations of the city of Yaound$\acute{e}$ show that the black carbon concentration is very considerable, the element sulfur is a major pollutant and the concentration of fine particle is very greater. The results obtained of fine and coarse filters range from $5-17{\mu}g/m^3$ and $10-18{\mu}g/m^3$ for the black carbon. S, Cu, Zn, Pb, Cd, As, Se and Hg are the specific findings of this work. The pollutants with a greater concentration are S, Pb, and Zn. These later seem to be non-uniformly, non-regular in some location and high compared to other countries. This work allows us to make a potential relation between pollutants and emission sources. In this framework, some suggestions have been proposed to reduce emissions for an improvement of the air quality in the environment and thus, the one of the city of Yaound$\acute{e}$.

• Environmental and Resource Economics Review
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• v.18 no.3
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• pp.495-521
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• 2009

This paper measures welfare losses from beef consumption reduction, which might be resulted from psychological anxiety about potential outbreak of BSE (commonly known as "bad cow dieses") risks after announcement of resuming US-beef imports in April of 2008. Unlike the previous literature of utilizing the contingent valuation method or experimental market approach, this study estimated quality-differentiated consumer demand functions using the information of self-reported beef consumption quantity, individually constructed price indices of beef, and subjective perception of BSE risks. The empirical results based on a survey sample of 360 residents in Jeon Ju city were consistent with the anticipation from economic theory, in terms of coefficients of own prices, substitute prices and income variables. The announcement of resuming US-beef imports did not make significant differences in the sign and sizes of the main economic variables. However, the subjective perception variable about BSE risks had negative significant impacts on beef demand functions after the announcement but not significant before the announcement. The welfare losses in a form of equivalent variation (EV) corresponding to the increases in concerns about BSE risks were measured to be about 30 thousand won per household.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.5A
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• pp.369-378
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• 2011

In this paper, the response analysis of RC(Reinforced Concrete), SC(Steel-Plate Concrete) containment buildings subjected to a large aircraft impact is performed using Autodyn-3D as Hydrocode. Until now, the impact load in the analysis of aircraft impacts has been applied to target structures at the local area by using the impact load-time history function of Riera. However in this paper, the results of aircraft crash are analyzed by using an aircraft model similar to Boeing 767 and verified by comparing the generated history of the aircraft crash against the rigid target with another history by using the Riera's function. To estimate the resistivity of the impact, the response and safety of SC containment buildings, this study is performed by comparing the four cases of plane concrete, reinforced concrete, bonded containment liner plate at reinforced concrete, and SC structure. Thus, the different behaviors between SC and RC structures when they are subjected to the extreme impact load could be anticipated. Consequently, the improved safety is expected by replacing RC structure with SC structure for nuclear power plants.

• Journal of the Korea Institute of Building Construction
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• v.13 no.5
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• pp.465-473
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• 2013

Concrete is an outstanding material in terms of its impact and blast resistance performance. However, there a limitation of concrete is its risk of collapse due to the brittle failure and spalling. Increasing the thickness of members was used as a method to enhance the protective performance of concrete, despite the resulting inefficient space. To solve this problem, different types of fiber reinforced concrete were developed. Recently, another type of fiber reinforced concrete is also being developed and applied as a material that offers protection against impacts and blasts by increasing the flexural toughness of concrete. In this study, the test was conducted to evaluate the impact resistance performance of fiber reinforced concrete and mortar according to impact of high-velocity projectile. A concrete T-wall was also tested to evaluate its protective performance from fragment by 155mm-thick artillery shell. The test results revealed that improving flexural strength through fiber reinforcement inhibited cracks and spalling of rear, and spalling of front by high-velocity impact. As such, it is expected to improve the protective performance of the T-wall and reduce the thickness of the member.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.40 no.1
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• pp.1-11
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• 2020

Medium to large post structures installed along the roadside without proper protection can lead to serious vehicle damage and occupant injury at the impact. In North America and Europe, splitting systems such as slip base or breakaway device are used to reduce impacts. But the system has the risk of secondary accident when the splitted post falls down to the traffic or pedestrian. Sliding Post have been proposed as a way to solve this problem. By studying the crash test results of the 1.3ton and 0.9ton vehicle with 60 km/h and 80 km/h to a Rigidly Fixed Post (RFP) and Sliding Post (SP), danger of the conventional RFP and crashworthiness of the SP have been proven. While collision analysis only from the acceleration measured at the center of the vehicle assumes the motion of the post is the same as that of the vehicle, in this paper, by adding high speed film data to the analysis with vehicle acceleration could have separate the post motion from the vehicle motion. It gives better explanations on the movement of post and vehicle in each distinctive time step and provides basics to the crashworthy post design.

• Korean Journal of Ecology and Environment
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• v.50 no.2
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• pp.195-206
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• 2017

We described a spatial distribution pattern and floral diversity on the Paspalum distichum community occurring at the ecological parks of Hwamyeong, Daejeo, Samnak, and Maekdo in the Nakdong river estuary. A total distribution area of P. distichum community was $303,462.6m^2$. Its largest area was found in Samnak eco-park ($185,910.1m^2$). The most richness of knotgrass patches in each ecological park was determined Maekdo eco-park (87). Cover class level-5 shows the largest area ($260,663.2m^2$). A total of 73 taxa (34 families, 55 genus, 65 species, and 8 varieties) were listed up on the P. distichum community. A welldeveloped population of knotgrass was found predominantly at sites linked into human impacts at the riverine floodplain, the stream courses flowing through the parks, and the man-made channels and wetlands. Finally we proposed an ecological management strategy for knotgrass population in the study area.

• Journal of Korea Spatial Information System Society
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• v.10 no.4
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• pp.27-35
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• 2008

Current re-arrangement of rivers and waterways have been made uniformly ignoring characteristics of individual rivers thereby aggravating artificial river restructuring. On the contrary, quantitative techniques to evaluate the aftermath of artificial river disturbance such as uprising of river bed, intrusion of foreign fisheries, and changes of ecological habitats are not available. To establish such quantitative techniques, analysis of the river changes to evaluate the major causes of the river disturbance and its impacts is essential. Therefore, research for proposing a method which can be applied for the development of techniques to investigate river disturbance according to the major factors for the domestic rivers using airphotos and GIS techniques was preceded. In this study, the study area on the downstream of the river was selected and analysis of river disturbance using preceding method was done to confirm the benefit of analyzing river disturbance using GIS techniques. Trend analysis of the waterway sinuosity and changes of the flow path leaded to detailed verification of the river disturbance for specific location or time period, and this enabled to generate relatively accurate numbers representing sinuosity of the waterway and relevant changes. Also, it is possible to predict the effect on the current re-arrangement of the river and waterway to river flow using the analysis of past river change. It is necessary to establish GIS based proper measures for environmental river restoration using the results from this study and future works.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.1
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• pp.135-143
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• 2014

This study classified abnormal sea surface temperature changes of the central pacific region according to three evolution patterns. Focusing on typhoons that affect the Korean Peninsula, the research analyzed typhoon's occurrence spot and track, change in the central pressure characteristics, and the characteristics of change in typhoon precipitation and the number of occurrences of heavy rainfall in the Nakdong River Basin. As a result of analysis, in case of prolonged-decaying years and symmetric-decaying years, typhoon-related summer rainfall and heavy rainy days appeared to be higher than long-term average. But in case of abrupt-decaying years, the pattern of general decrease appeared. This is because typhoon's occurrence spot is located comparatively near the Korean peninsula, typhoon's central pressure is high, and typhoon's route generally moves to Japan. As the outcome, this study is expected to reduce flood damage through analyzing the characteristics of typhoon's activity according to CP El Ni$\tilde{n}$o evolution patterns and the characteristics of local typhoon rainfall. In addition, it is expected to provide useful information for establishing adaptation and mitigation to climate change.