• Journal of Bio-Environment Control
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• v.28 no.2
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• pp.150-157
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• 2019

This study was carried out to investigate at the micrometeorology change of the orchard according to the net installation. Two weather stations were installed at the inside of the anti-insect nets(2 mm, 4 mm), one was installed at the outside(control). They were observed the temperature, humidity, wind speed and solar radiation from April to September 2018. Daily mean temperature at the experimental group was higher than control group by $0.2^{\circ}C$. Daily mean humidity at the experimental group was higher than control group by 3.5 to 4.7%. Daily mean the solar radiation at the experimental group(2 mm) was lower than control group by 50%. The wind speed was decreased from 12% to 50% of the external wind speed at 4 mm, and from 25% to 59% at 2 mm.

• Journal of the Korean Association of Geographic Information Studies
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• v.23 no.4
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• pp.253-265
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• 2020

As the risk of landslide is recently increasing due to the typhoons and localized heavy rains, effective techniques for the landslide damage detection are required to support the establishment of the recovery planning. This study describes the analysis of landslide-damaged areas using ISODATA(Iterative Self-Organizing Data Analysis Technique Algorithm) with Sentinel-2 image, regarding the case of Gokseong in August 7, 2020. A total of 4.75 ha of landslide-damaged areas was detected from the Sentinel-2 image using spectral characteristics of red, NIR(Near Infrared), and SWIR(Shortwave Infrared) bands. We made sure that the satellite remote sensing is an effective method to detect the landslide-damaged areas and support the establishment of the recovery planning, followed by the field surveys that require a lot of manpower and time. Also, this study can be used as a reference for the landslide management for the CAS500-1/2(Compact Advanced Satellite) scheduled to launch in 2021 and the Korean Medium Satellite for Agriculture and Forestry scheduled to launch in 2024.

• Journal of Korean Society of Disaster and Security
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• v.16 no.1
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• pp.105-113
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• 2023

Jeollanam-do has 25 land-to-island and island-to-island bridges, the largest number in Korea. It is a local government rich in specialized marine and tourism resources centered on the archipelago and the sea bridges connecting them. However, in the case of sea-crossing bridges, when strong winds or typhoons occur, there is an issue that increases anxiety among users and local residents due to excessive vibration of the bridge, apart from structural safety of the bridge. In fact, in the case of Cheonsa Bridge in Shinan-gun, which was recently opened in 2019, vehicle traffic restrictions due to strong winds and excessive vibrations frequently occurred, resulting in complaints from local residents and drivers due to increased anxiety. Therefore, based on the data measured using IoT measurement technology, it is possible to relieve local residents' anxiety about the safety management of marine bridges by providing quantitative and accurate bridge vibration levels related to traffic and wind conditions of bridges in real time to local residents. This study uses the existing measurement system and IoT sensor to constantly observe the wind speed and vibration of the marine bridge, and transmits it to local residents and managers to relieve anxiety about the safety and traffic of the sea-crossing bridge, and strong winds and to develop technologies capable of preemptively responding to large-scale disasters.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.2
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• pp.149-156
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• 2023

Recently, concerns about natural disasters such as earthquakes, tsunamis and typhoons have increased. As the magnitude and frequency of earthquakes increase, research is needed to prevent structures from collapsing due to earthquake loads. Research is needed to increase the ductility of columns to prevent the collapse of structures. In this study, the ductility improvement of square columns achieved by applying spiral stirrups to square columns. Square columns reinforced with spiral stirrups are more resistant to repetitive loads such as seismic loads than columns reinforced with tie stirrups. Also, the spiral stirrups can apply better confinement to the concrete. In this study, an uniaxial compression test was conducted to evaluate the performance of columns reinforced with spiral stirrups. The results showed that the columns reinforced with spiral stirrups in both the circular and square columns showed higher compressive strength than the columns reinforced with the tie stirrups. In addition, the columns reinforced with spiral stirrups for both the square and circle columns, showed a tendency to endure the load even after the initial cracking and rebar yielding.

• Journal of the Korean Geotechnical Society
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• v.39 no.12
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• pp.47-60
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• 2023

At present, in South Korea, there is a growing concern regarding solar power facilities installed on slopes because they are prone to damage caused by natural disasters, such as heavy rainfall and typhoons. Each year, these solar power facilities experience soil erosion due to heavy rainfall and foundation damage or detachment caused by strong wind loads. Despite these challenges, the interaction between the ground and structures is not adequately considered. Current analyses primarily focus on the structural stability under external loads; the overall facility site's stability-excluding the solar structures-in relation to its surrounding slopes is neglected. Therefore, in this study, we use finite-difference method analysis to simulate the behavior of the foundation and piles to assess changes in lateral displacement and bending stress in piles, as well as the safety factor of sloped terrains, in response to various influencing factors, such as pile diameter, spacing between piles, pile-embedding depth, wind loads, and dry and wet conditions. The analysis results indicate that pile spacing and wind loads significantly influence lateral displacement and bending stress in piles, whereas pile-embedding depth strongly influences the safety factor of sloped terrains. Moreover, we found that under certain conditions, the design criteria in domestic standards may not be met.

• Korean Journal of Environmental Agriculture
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• v.33 no.4
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• pp.321-326
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• 2014

BACKGROUND: Recently, weather disasters such as hail and typhoon occur frequently. These threaten the stable cultivation of potatoes. It is very important to cultivate potatoes with stable under unexpected weather disasters. This study was performed to investigate the correlation between mophological characteristics of potato stem and its resistance to hail damage in different potato cultivars. METHODS AND RESULTS: Hail fall occurred for 8 minutes on May 31, 2012 in the field of Highland Agriculture Research Center located in Jinbu-myeon Gangwon-do. Potato crop grown in the field was affected by hail due to which the stems of potato were broken. The percentage of broken stem of potato was investigated as the level of damage by hail. To determine the difference in the ratio of broken stem among the potato cultivars, physical characteristics of potato stem such as diameter and hardness were measured. To evaluate recovery phase after hail damage, ground coverage and yield were measured. The percentage of broken stem of cv. Goun and cv. Saebong were 30%, 26%, respectively, whereas it was 5% in the cv. Atlantic. Damage by hail was the lowest in cv. Atlantic. Diameter of the stem was 15 mm in cv. Atlantic, 13 mm in cv. Goun and 11 mm in cv. Saebong. The hardness of potato cultivars was measured which was 74 N in cv. Atlantic. 71 N in cv. Goun and 59 N in cv. Saebong. The ground coverage in cv. Atlantic was 79%, which was the highest followed by 73% in cv. Saebong and 56% in cv. Goun. The yield of cv. Atlantic was monitored at 90 days after planting which was 40 MT/ha and that of cv. Saebong was 36 MT/ha, whereas in cv. Goun, it was 30 MT/ha which was the lowest. CONCLUSION: The ratio of broken stem in cv. Atlantic was the lowest compared to cultivars. In the physical characteristics of stem, cv. Atlantic was the highest in value of diameter and hardness. Based on these results, it was considered that cv. Atlantic was resistant to hail damage compared to other cultivars.

• Korean Journal of Remote Sensing
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• v.36 no.2_2
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• pp.351-363
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• 2020

It is well known that alluvial sediment located in coastal region has been easily affected by geohazard like ground subsidence, marine or meteorological disasters which threaten invaluable lives and properties. The subsidence is a sinking of the ground due to underground material movement that mostly related to soil compaction by water extraction. Thus, continuous monitoring is essential to protect possible damage from the ground subsidence in the coastal region. Radar interferometric application has been widely used to estimate surface displacement from phase information of synthetic aperture radar (SAR). Thanks to advanced SAR technique like the Small BAseline Subset (SBAS), a time-series of surface displacement could be successfully calculated with a large amount of SAR observations (>20). Because the ALOS-2 PALSAR-2 L-band observations maintain higher coherence compared with other shorter wavelength like X- or C-band, it has been regarded as one of the best resources for Earth science. However, the number of ALOS-2 PALSAR-2 observations might be not enough for the SBAS application due to its global monitoring observation scenario. Unfortunately, the number of the ALOS-2 PALSAR-2 Stripmap images in area of our interest, Busan which located in the Southeastern Korea, is only 11 which is insufficient to apply the SBAS time-series analysis. Although it is common that the radar interferometry utilizes multiple SAR images collected from same acquisition mode, it has been reported that the ALOS-2 PALSAR-2 Stripmap-ScanSAR interferometric application could be possible under specific acquisition mode. In case that we can apply the Stripmap-ScanSAR interferometry with the other 18 ScanSAR observations over Busan, an enhanced time-series surface displacement with better temporal resolution could be estimated. In this study, we evaluated feasibility of the ALOS-2 PALSAR-2 Stripmap-ScanSAR interferometric application using Gamma software considering differences of chirp bandwidth and pulse repetition frequency (PRF) between two acquisition modes. In addition, we analyzed the interferograms with respect to spectral shift of radar carrier frequency and common band filtering. Even though it shows similar level of coherence regardless of spectral shift in the radar carrier frequency, we found periodic spectral noises in azimuth direction and significant degradation of coherence in azimuth direction after common band filtering. Therefore, the characteristics of spectral bandwidth in the range and azimuth direction should be considered cautiously for the ALOS-2 PALSAR-2 Stripmap-ScanSAR interferometry.

• Korean Journal of Heritage: History & Science
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• v.48 no.1
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• pp.24-43
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• 2015

This study constitutes an inquiry into the decline of Government Office(官衙) facilities carried out intensively during modern era, focusing on provincial government offices of Jeollabuk-do. There have been several studies of changes in provincial government offices till now, but there have been few studies of government offices of the counties and prefectures(郡縣) during the period of the Japanese Resident-General of Korea and after the National Liberation, temporally and there have still been lacking studies on Jeollabuk-do, spatially. Thus, this study attempts to empirically prove the reasons and the time of the decline of provincial government offices in Jeollabuk-do and the characteristics in the process of decline focusing on modern era. As a result of the study, four factors: demolition, abolition, appropriation and disaster had the most decisive impacts on the decline of government office facilities. Demolition refers to the destruction of government office facilities, and abolition, to the decline and the discontinuation of the operation of the facilities. Appropriation refers to conversion to facilities to meet public functions, and disaster, damage from a typhoon or fire. These factors had already been started from the 1900s, and by the 1930s, most of the government office facilities came to lose their original looks and functions. In the meantime, there was an essential purpose in demolition, the most direct factor in the destruction of the government office facilities in terms of function: that is new construction of public facilities necessary for administration and rule. The existing government office facilities were appropriated, sometimes, but behind that, many cases of demolition of the government office facilities for the new construction of public facilities are found. The appropriation of the government office facilities is divided into educational, administrative, financial and security facilities, and generally, Gaeksa(客舍) and Dongheon(東軒) were used respectively as educational and administrative facilities while their attached facilities were used as financial and public order and security facilities in general. Especially, some government office facilities were utilized as distinctive facilities such as housing or hospital. In the process of appropriation, a lot of modification occurred inside and outside the government office facilities, due to which, the government office facilities gradually declined losing their traditional styles.

• Journal of The Korean Society of Grassland and Forage Science
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• v.27 no.4
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• pp.297-312
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• 2007

This study is conducted to evaluate economical value of Jeju grassland and validity of its preservation, and draw up several measures to support. To measure its economical value, this study examined its environmental value and social and cultural value. For environmental value, this study used replacement method while it applied CVM method, a widely used method, to assess social and cultural value and two-level two-best choice selection method, which ask questions by assuming virtual circumstances to avoid reflecting some biased opinions. Jeju grassland has multiple functions-environmental functions such as preventing soil corrosion and flood, handling animal excrement, and purifying air, and social and cultural functions such as promoting physical and mental health and providing recreation places. From the results of the feasibility study, Jeju grassland's annual multiple functions are assessed to have a total $397,115{\sim}418,995$ million won worth. In addition, it is found that Jeju visitors recognize Jeju grassland for its functions to contribute to public interests. That is, they think it can provide attractive views and educational and recreational places and promote emotional development. Especially, many people presented their ideas that it be continuously preserved since it is worthwhile for us and our next generations. To preserve grassland's cultural resource, which create a huge economic value like this, the Government has to support a certain amount of financial aid for turning to a better grassland environment and its maintenance to realize environment-friendly livestock farming on Jeju Island and promote its tourism industry and consequently, add more value to Jeju.