• Journal of Korean Tunnelling and Underground Space Association
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• v.24 no.5
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• pp.431-449
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• 2022

As many tunnels generally have been constructed, various experiences and techniques have been accumulated for tunnel design as well as tunnel construction. Hence, there are not a few cases that, for some usual tunnel design works, it is sufficient to perform the design by only modifying or supplementing previous similar design cases unless a tunnel has a unique structure or in geological conditions. In particular, for a tunnel blast design, it is reasonable to refer to previous similar design cases because the blast design in the stage of design is a preliminary design, considering that it is general to perform additional blast design through test blasts prior to the start of tunnel excavation. Meanwhile, entering the industry 4.0 era, artificial intelligence (AI) of which availability is surging across whole industry sector is broadly utilized to tunnel and blasting. For a drill and blast tunnel, AI is mainly applied for the estimation of blast vibration and rock mass classification, etc. however, there are few cases where it is applied to blast pattern design. Thus, this study attempts to automate tunnel blast design by means of machine learning, a branch of artificial intelligence. For this, the data related to a blast design was collected from 25 tunnel design reports for learning as well as 2 additional reports for the test, and from which 4 design parameters, i.e., rock mass class, road type and cross sectional area of upper section as well as bench section as input data as well as16 design elements, i.e., blast cut type, specific charge, the number of drill holes, and spacing and burden for each blast hole group, etc. as output. Based on this design data, three machine learning models, i.e., XGBoost, ANN, SVM, were tested and XGBoost was chosen as the best model and the results show a generally similar trend to an actual design when assumed design parameters were input. It is not enough yet to perform the whole blast design using the results from this study, however, it is planned that additional studies will be carried out to make it possible to put it to practical use after collecting more sufficient blast design data and supplementing detailed machine learning processes.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.40 no.2
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• pp.69-77
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• 2022

The 3D spatial model is an analysis framework for solving urban problems and is used in various fields such as urban planning, environment, land and housing management, and disaster simulation. The utilization of drones that can capture 3D images in a short time at a low cost is increasing for the construction of 3D spatial model. In terms of building a virtual city and utilizing simulation modules, high location accuracy of aerial survey and precision of 3D spatial model function as important factors, so a method to increase the accuracy has been proposed. This study analyzed location accuracy of aerial survey and precision of 3D spatial model by each condition of aerial survey for urban areas where buildings are densely located. We selected Daerim 2-dong, Yeongdeungpo-gu, Seoul as a target area and applied shooting angle, shooting altitude, and overlap rate as conditions for the aerial survey. In this study, we calculated the location accuracy of aerial survey by analyzing the difference between an actual survey value of CPs and a predicted value of 3D spatial Model. Also, We calculated the precision of 3D spatial Model by analyzing the difference between the position of Point cloud and the 3D spatial Model (3D Mesh). As a result of this study, the location accuracy tended to be high at a relatively high rate of overlap, but the higher the rate of overlap, the lower the precision of 3D spatial model and the higher the shooting angle, the higher precision. Also, there was no significant relationship with precision. In terms of baseline-height ratio, the precision tended to be improved as the baseline-height ratio increased.

• Journal of Korea Water Resources Association
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• v.55 no.10
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• pp.723-736
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• 2022

In this study, monthly precipitation forecasting models that can predict up to 12 months in advance were constructed for the Geum River basin, and two statistical techniques, multiple linear regression (MLR) and artificial neural network (ANN), were applied to the model construction. As predictor candidates, a total of 47 climate indices were used, including 39 global climate patterns provided by the National Oceanic and Atmospheric Administration (NOAA) and 8 meteorological factors for the basin. Forecast models were constructed by using climate indices with high correlation by analyzing the teleconnection between the monthly precipitation and each climate index for the past 40 years based on the forecast month. In the goodness-of-fit test results for the average value of forecasts of each month for 1991 to 2021, the MLR models showed -3.3 to -0.1% for the percent bias (PBIAS), 0.45 to 0.50 for the Nash-Sutcliffe efficiency (NSE), and 0.69 to 0.70 for the Pearson correlation coefficient (r), whereas, the ANN models showed PBIAS -5.0~+0.5%, NSE 0.35~0.47, and r 0.64~0.70. The mean values predicted by the MLR models were found to be closer to the observation than the ANN models. The probability of including observations within the forecast range for each month was 57.5 to 83.6% (average 72.9%) for the MLR models, and 71.5 to 88.7% (average 81.1%) for the ANN models, indicating that the ANN models showed better results. The tercile probability by month was 25.9 to 41.9% (average 34.6%) for the MLR models, and 30.3 to 39.1% (average 34.7%) for the ANN models. Both models showed long-term predictability of monthly precipitation with an average of 33.3% or more in tercile probability. In conclusion, the difference in predictability between the two models was found to be relatively small. However, when judging from the hit rate for the prediction range or the tercile probability, the monthly deviation for predictability was found to be relatively small for the ANN models.

• Journal of the Korean earth science society
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• v.43 no.1
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• pp.41-59
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• 2022

In accordance with the enactment of 'the Paris Agreement' in 2015 and 'the Framework Act on Carbon Neutrality and Green Growth for Response to the Climate Crisis' in 2021, each local government has set appropriate reduction target of greenhouse gas to achieve the nationally determined contribution (NDC, the reduction target of 40% compared to 2018) of greenhouse gas (GHG) emissions in 2030. In this study, the current distribution of GHG emissions was analyzed in a time series centered on the Chungbuk region for the period from 1990 to 2018, with the aim of reducing GHG emissions in Chungbuk by 2030 based on the 2030 NDC and scenario. In addition, the prospected reduction by 2030 was estimated considering the projected emissions according to Busines As Usual in order to achieve the target reduction of GHG emissions. Our results showed that GHG emissions in Chungbuk and Korea have been increasing since 1990 owing to population and economic growth. GHG emissions in 2018 in Chungbuk were very low (3.9 %) relative to the national value. Moreover, emissions from fuel combustion, such as cement and lime production, manufacturing and construction industries, and transportation industries, were the main sources. Furthermore, the 2030 target of GHG emission reduction in Chungbuk was set at 40.2% relative to the 2018 value, in accordance with the 2030 NDC and 2050 carbon-zero national scenario. Therefore, when projected emissions were considered, the prospected reduction to achieve the target reduction of GHG emissions was estimated to be 46.8% relative to 2018. The above results highlight the importance of meeting the prospected reduction of GHG emissions through reduction means in each sector to achieve the national and local GHG reduction target. In addition, to achieve the 2030 NDC and 2050 carbon zero, the country and each local government, including Chungbuk, need to estimate projected emissions by year, determine reduction targets and prospect reductions every year, and prepare specific means to reduce GHG emissions.

• Journal of Environmental Impact Assessment
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• v.31 no.1
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• pp.11-46
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• 2022

This study was carried out to examine vascular plants and invasive alien plants in Gyodong Island, located at the northwestern Civilian Control Line (CCL) of Ganghwa-gun, Incheon, and to use them as basic data for systematic management of identified plants and establishing biodiversity conservation measures. The survey was conducted 13 times from April 2019 to August 2021. The vascularflora in Gyodong Island was identified as 109 families, 378 genera, 641 species, 15 subspecies, 49 variants, 8 forma, a total of 713 taxa. This was found to be about 15.36% of the total 4,641 taxa of vascular plants in Korea. The northern linage plants on the Korean Peninsula appearing in the Gyodong Island area were identified in 83 classification groups, including Red-based leaf edge (Carex erythrobasis H.Lev. & Vaniot). Korea endemic plants were identified as 16 taxa such as Seoul wild-ginger [Asarum heterotropoides var. seoulense (Nakai) Kitag.], and a total of 20 taxa of rare plants designated by IUCN were observed, including the endangered grade Beardless iris (Iris ruthenica Ker Gawl.). Floristic target species were classified with a total of 99 taxa. For V grade, Beardless iris 1 taxon was found. and also IV grade and III grade were identified in 8 taxa and 20 taxa respectively. The invasive alien plants identified as 75 taxa, such as Verbesina alternifolia (L.) Britton ex Kearney. The naturalization rate was 10.51%, and the urbanization index was calculated as 23.29%. Since large-scale construction has been currently underway on Hwagae Mt. in Gyodong Island as the target of survey area, the influx of invasive plants will be expected to promote. Therefore, it is urgent to establish in-situ protection and conservation measures for notable plants such as Beardless iris and Water smartweed [Persicaria amphibia (L.) S.F.Gray].

• Membrane Journal
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• v.32 no.4
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• pp.235-252
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• 2022

Forward osmotic pressure-free reverse osmosis (Δ𝜋=0 RO) was invented in 2013. The first patent (US 9,950,297 B2) was registered on April 18, 2018. The "Osmotic Pressure of Concentrated Solutions" in JACS (1908) by G.N. Lewis of MIT was used for the estimation. The Chang's RO system differs from conventional RO (C-RO) in that two-chamber system of osmotic pressure equalizer and a low-pressure RO system while C-RO is based on a single chamber. Chang claimed that all aqueous solutions, including salt water, regardless of its osmotic pressure can be separated into water and salt. The second patent (US 10.953.367B2, March 23, 2021) showed that a low-pressure reverse osmosis is possible for 3.0% input at Δ𝜋 of 10 to 12 bar. Singularity ZERO reverse osmosis from his third patent (Korea patent 10-22322755, US-PCT/KR202003595) for a 3.0% NaCl input, 50% more water recovery, use of 1/3 RO membrane area, and 1/5th of theoretical energy. These numbers come from Chang's laboratory experiments and theoretical analysis. Relative residence time (RRT) of feed and OE chambers makes Δ𝜋 to zero or negative by recycling enriched feed flow. The construction cost by S-ZERO was estimated to be around 50~60% of the current RO system.

• Journal of Environmental Impact Assessment
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• v.32 no.1
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• pp.1-14
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• 2023

When carrying out development projects around Ardeidae breeding habitats, we intend to devise a plan for sustainable coexistence by presenting measures to select and reduce key evaluation items so that conflicts can be prevented in advance at the environmental impact assessment stage. The results of the study are as follows. The main evaluation items are animal and plant items for preservation of Ardeidae breeding habitats and odor and noise items that can evaluate the effects of odors and noise in Ardeidae breeding habitats. First, the scope of the survey in animals and plants categories is not limited to legal guardian species, but includes egrets breeding and feeding grounds corresponding to major species breeding grounds and migratory birds, and preservation measures are established according to the reduction of the area of breeding and feeding grounds. Second, in the odor category, the irradiation period includes the period when the odor generation is the highest from the end of June to the end of July. The odor evaluation standard is based on the complex odor discharge standard, which is a concentration regulation, and the odor concentration felt by humans shall be 2 to 5OU/m³ and the frequency shall be 2% or less. Third, in the noise category, the timing of the survey is measured every month from May to August, including when the sound of egrets and young birds is combined to maximize noise generation. Since the noise of Ardeidae, a bird in summer, occurs only for a certain period of time, measures are taken to reduce noise by securing separation distances, securing buffer green areas, and installing construction rather than installing artificial structures such as soundproof walls. In order for existing Ardeidae breeding sites to maintain an appropriate density of populations and not move populations elsewhere, it is necessary to manage nesting tree and maintain stable habitat quantity and quality.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.41 no.2
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• pp.11-18
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• 2023

This study aims to distinguish what can be used in consideration of the national situation with Korea for Chinese Scenic and Historic Interest Areas, and the results are as follows; First, the Chinese Scenic and Historic Interest Areas expanded to the existing scenic cruise culture, travel, and tourism culture in the process of the influx of Western culture in the modern and contemporary era, and became popular as a travel destination. Accordingly, the Chinese government developed the tourism industry around the scenic sites, and thanks to the development of transportation and communication, the Scenic and Historic Interest Areas has become an important national heritage. This influenced the establishment of the system related to Scenic and Historic Interest Areas, and today, it is operated around the Scenic and Historic Interest Areas ordinance. Second, the designation of the Scenic and Historic Interest Areas is divided into the size of the site according to the area, and the process of selecting the Scenic and Historic Interest Areas classification, rating evaluation, and comprehensive value evaluation according to evaluation indicators and rating standards is carried out. Accordingly, according to the results of the classification, it is subdivided from the national level to the Scenic and Historic Interest Areas at the local level. Third, the central government is in charge of managing and supervising Scenic and Historic Interest Areas across the country, and the local government's construction department is in charge of supervising Scenic and Historic Interest Areas in the region. The management organization of Scenic and Historic Interest Areas established by local governments above the county level has a system that actually protects, utilizes, and manages Scenic and Historic Interest Areas. In addition, 14 detailed indicators are used to monitor Scenic and Historic Interest Areas. Based on these results, considering the application of the domestic scenic site policy, the method of developing the policy that has established the system from the perspective of the utilization of the people is worth considering. On the other hand, the evaluation of the designation and management system through the setting of various indicators has limitations in that it is difficult to secure objectivity in impressing or evaluating the landscape. Therefore, rather than blindly introducing quantified evaluation, it seems that guidance and promotion on how to expand consensus on scenic values and enjoy heritage should be prioritized.

• Korean Journal of Environment and Ecology
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• v.36 no.6
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• pp.676-683
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• 2022

Due to the effects of rapid changes in the living environment since 2000 and the recent unforeseen pandemic, people are refraining from domestic and international traveling and movement, and outdoor activities for health and the public value of forest trails, called Dullegil Trail in Korea, have become more important. This study estimated the environmental value of the tentatively named "East-West Trail," which connects the forest trails crossing Chungcheong and Gyeongsang Provinces using CVM (Contingent Valuation Method). It surveyed visitors to the East-West Trail, and 725 questionnaires were used for analysis. The average characteristics of respondents were those who exercised 2-3 times per week, visited a forest trail not far from their residence with friends or family, and showed a tendency to spend 50 thousand Korean won or more per visit. Visitors to the Dullegil Trail felt that there was a shortage of information boards on the forest trail, and they preferred a shelter in appropriate locations. We used a double-bounded dichotomous choice (BDDC) logit model proposed by Hanemann to measure the conservation value of the East-West Trail. It was estimated that the environmental value that a visitor to the East-West Trail could obtain was 30,087 won per trip. The estimated environmental value of the East-West Trail can be converted to about 94 billion won total visitors annually based on the population belonging to the direct-use zone near the East-West Trail. As there has been no study on the environmental value of forest trails using CVM, the results of this study will be able to suggest the feasibility of the government policies on forest trails.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.41 no.1
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• pp.35-46
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• 2023

This study investigated and analyzed ancient records on the type, planting background, and construction process of Gwanbang forest(關防林) planned for military defense during the Joseon Dynasty to find out the purpose, location, and planting species of Gwanbang forest. The research results were as follows. During the Joseon Dynasty, Gwanbang forests were created around various government facilities(關防施設), such as Eupseong(邑城), major government offices, camps, and fortifications, for the purpose of defending against enemies. Gwanbang forest includes Yeongaeglim(嶺阨林), which was created on the crest of a strategically important hill, and Military Forest created for military purposes. Most of the spirit forest was designated as Geumsan(禁山) and protected and managed, and the Gwanbang forest was created for various purposes such as shielding, flood damage and river bank erosion prevention as well as external defense. In addition, in order to continuously and efficiently produce wood, which is a material for ships, buildings, and agricultural tools, in most cases, large areas were created as mixed forests. As for the species constituting the Gwanbang forest, there are records of tangerine tree, which is effective for defense because it has thorns, and deciduous broad-leaved trees such as zelkova, elm, willow, david hemiptelea, and oak appear. In the case of Ganghwa island, which served as the defense of the capital and the royal family during the Joseon Dynasty, several records have confirmed that a forest densely planted with trifoliate orange was created for the purpose of Gwanbang forest to reinforce the defense of the outer fortress. Based on historical research in the literature, assuming that the natural monument 'Gapgotri tangerine tree in Ganghwa Island' was planted in the 30th year of King Sukjong(1704), the first record of planting trifoliate orange in Ganghwa Island, the maximum age is estimated to be more than 319 years.