• Economic and Environmental Geology
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• v.52 no.2
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• pp.169-188
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• 2019

This study was carried out unmanned aerial photography and terrestrial laser scanning to establish digital database on original wall of Gyejoksanseong fortress, and measured ground control points for continuity of the monitoring. It also performed precise examination with the naked eye, unmanned aerial photogrammetry, endoscopy, total station and handy measurement to examine the structural stability of the original walls. The ground control points were considered as a point where visual field can be secured, 3 points were selected around each of the south and north walls. For the right side of the south original wall, aerial photogrammetry was conducted using drones and a deviation analysis of 3-dimensional digital models was performed for short-term monitoring. As a result, the two original walls were almost matched in range within 5mm, and no difference indicating displacement of stones was found, except for partial deviation. Regular monitoring of the areas with structural deformation such as bulging, weak and fracture zone by precisely examining with the naked eye and using high-resolution photo data revealed no distinct change. The inner foundation observed through endoscopy found out that filling stones of the original walls were still remained, while most filling soil was lost. As a result of measuring the total station focusing around the points with structural deformation on the original walls, the maximum displacements of the north and south walls were somewhat high with 6.6mm and 3.8mm, respectively, while the final displacements were relatively stable at below 2.9mm and 1.4mm, respectively. Handy measurement also did not reveal clear structural deformation with displacements below 0.82mm at all points. Even though the results of displacement monitoring on the original walls are stable, it is hard to secure structural stability due to the characteristics of ramparts where sudden brittle fracture occurs. Therefore, it is necessary to conduct conservational scientific diagnosis, precise monitoring, and structural analysis based on the 3-dimensional figuration information obtained in this research.

• Journal of Bio-Environment Control
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• v.28 no.4
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• pp.366-375
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• 2019

This experiment aims to determine the proper irrigation scheduling based on a whole-substrate capacitance using a newly developed device (SCMD) by comparing with the integrated solar radiation automated irrigation system (ISR) and sap flow sensor automated irrigation system (SF) for the cultivation of tomato (Solanum lycopersicum L. 'Hoyong' 'Super Doterang') during spring to winter season. For the SCMD system, irrigation was conducted every 10 minutes after the first irrigation was started until the first run-off was occurred, of which the substrate capacitance was considered to be 100%. When the capacitance threshold (CT) was reached to the target point, irrigation was re-conducted. After that, when the target drain volume (TDV) was occurred, the irrigation stopped. The irrigation volume per event for the SCMD was set to 50, 75, or 100 mL at CT 0.9 and TDV 100 mL during the spring to summer cultivation, and the CT was set to 0.65, 0.75, 0.80, or 0.90 in the winter cultivation. When the irrigation volume per event was set to 50, 75, or 100 mL, the irrigation frequency in a day was 39, 29, and 19, respectively, and the drain rate was 3.04, 9.25, and 20.18%, respectively. When the CT was set to 0.65, 0.75, or 0.90 in winter, the irrigation frequency was about 6, 7, 15 times, respectively and the drain rate was 9.9, 10.8, 35.3% respectively. The signal of stem sap flow at the beginning of irrigation starting time did not correspond to that of solar irradiance when the irrigation volume per event was set to 50 or 75 mL, compared to that of 100 mL. In winter cultivation, the stem sap flow rate and substrate volumetric water content at the CT 0.65 treatment were very low, while they were very high at CT 0.90 was high. All the integrated data suggest that the proper range of irrigation volume per event is from 75 to 100 mL under at CT 0.9 and TDV 100 mL during the spring to summer cultivation, and the proper CT seems to be higher than 0.75 and lower than 0.90 under at 75 mL of the irrigation volume per event and TDV 70 mL during the winter cultivation. It is going to be necessary to investigate the relationship between capacitance value and substrate volumetric water content by determining the correction coefficient.

• Korean Journal of Agricultural and Forest Meteorology
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• v.22 no.4
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• pp.327-339
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• 2020

Transpiration is the movement of water into the atmosphere through leaf stomata of plant, and it accounts for more than half of evapotranspiration from the land surface. The measurements of transpiration could be conducted in various ways including eddy covariance and water balance method etc. However, the transpiration measurements of individual trees are necessary to quantify and compare the water use of each species and individual component within stands. For the measurement of the transpiration by individual tree, the thermometric methods such as heat dissipation and heat pulse methods are widely used. However, it is difficult and labor consuming to maintain the transpiration measurements of individual trees in a wide range area and especially for long-term experiment. Therefore, the sharing of sapflow data through database should be useful to promote the studies on transpiration and water balance for large spatial scale. In this paper, we present sap flow database, which have Granier type sap flux data from 18 Korean pine (Pinus koraiensis) since 2011 and 16 (Quercus aliena) since 2013 in Mt.Taehwa Seoul National University forest and 18 needle fir (Abies holophylla), seven (Quercus serrata), three (Carpinus laxiflora and C. cordata each since 2013 in Gwangneung. In addition, the database includes the sapling transpiration of nine species (Prunus sargentii, Larix kaempferii, Quercus accutisima, Pinus densiflora, Fraxinus rhynchophylla, Chamecypans obtuse, P. koraiensis, Betulla platyphylla, A. holophylla, Pinus thunbergii), which were measured using heat pulse method since 2018. We believe this is the first database to share the sapflux data in Rep. of Korea, and we wish our database to be used by other researchers and contribute a variety of researches in this field.

• The Journal of Korean Society for Radiation Therapy
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• v.33
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• pp.47-54
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• 2021

Purpose : In order to evaluate the usefulness of clinical application of the Pause & Resume methods by comparing and analyzing the data stability and dose reduction effect when repeat scan assuming irregular breathing and using the Pause & Resume method during chest 4D CT using Quasar^TM Phantom. Materials and Methods : Using the Quasar^TM Phantom, set the breathing rate per minute to 15 BPM and 7.5 BPM, and set the S15 point as an irregular breathing section, and then placed OSLD to this point and use the Pause & Resume method to measure the dose of S15. CTDIvol, DLP, and ALARA-CT were used for comparative analysis of radiation dose between Pause & Resume method and Repeat-scan. In order to evaluate the stability and usability of the data applying the Pause & Resume method, the captured images were sorted by Advanced Workstation Volume Share7 and then sent to Eclipse^TM, the diameter and volume were analyzed by forming a contour on the iron ball in the Quasar^TM Phantom Results : When using Pause & Resume, the dose of OSLD measurement increased by 1.97 times in the section of S15. As a result of image evaluation, the average value of all volumes measured with and without the Pause & Resume method at 15 BPM and 7.5 BPM was 15.2 cm3±0.5%.Allthemeasuredvaluesfor the radius of iron ball were 3.1 cm regardless of whether Pause & Resume method was used or not. In the case of using Pause & Resume, 33% decreased from the lowest DLP value and 38% decreased from the highest DLP value of repeat scan, and the effective dose also decreased 32.1% from the minimum value and 37.6% from the maximum value. Conclusion: Irradiation dose was increased by Pause & Resume method because of the repeat scan on the S15 site where assuming irregular breathing occurred, However Pause & Resume method led to a significant reduction in dose on overall scan range. It also proved the usefulness of clinical application of the Pause & Resume method as a result of similar diameters and volumes of iron ball measurement.

• Korean Journal of Remote Sensing
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• v.38 no.6_3
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• pp.1827-1836
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• 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 Geotechnical Society
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• v.38 no.7
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• pp.5-24
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• 2022

The current performance evaluation of slope anchors qualitatively determines the physical bonding between the anchor head and ground as well as cracks or breakage of the anchor head. However, such performance evaluation does not measure these primary factors quantitatively. Therefore, the time-dependent management of the anchors is almost impossible. This study is an evaluation of the 3D numerical model by SfM which combines UAS images with terrestrial LiDAR to collect numerical data on the damage factors. It also utilizes the data for the quantitative maintenance of the anchor system once it is installed on slopes. The UAS 3D model, which often shows relatively low precision in the z-coordinate for vertical objects such as slopes, is combined with terrestrial LiDAR scan data to improve the accuracy of the z-coordinate measurement. After validating the system, a field test is conducted with ten anchors installed on a slope with arbitrarily damaged heads. The damages (such as cracks, breakages, and rotational displacements) are detected and numerically evaluated through the orthogonal projection of the measurement system. The results show that the introduced system at the resolution of 8K can detect cracks less than 0.3 mm in any aperture with an error range of 0.05 mm. Also, the system can successfully detect the volume of the damaged part, showing that the maximum damage area of the anchor head was within 3% of the original design guideline. Originally, the ground adhesion to the anchor head, where the z-coordinate is highly relevant, was almost impossible to measure with the UAS 3D numerical model alone because of its blind spots. However, by applying the combined system, elevation differences between the anchor bottom and the irregular ground surface was identified so that the average value at 20 various locations was calculated for the ground adhesion. Additionally, rotation angle and displacement of the anchor head less than 1" were detected. From the observations, the validity of the 3D numerical model can obtain quantitative data on anchor damage. Such data collection can potentially create a database that could be used as a fundamental resource for quantitative anchor damage evaluation in the future.

• Korean Journal of Heritage: History & Science
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• v.55 no.4
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• pp.180-193
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• 2022

The East Nine Royal Tombs is a representative place in the Royal Tombs of Joseon (a World Heritage Site). It consists of 1,289 stone artifacts including 979 related stone structures, 310 stone statues, and objects. Most of the stone structures in the East Nine Royal Tombs are composed of biotite granite, but some tombs are composed of light red granite. As a result of magnetic susceptibility measurement, the average data from Geonwolleung to Mongneung, excluding Hyeolleung, were similar, so it is estimated that stones were obtained from the same quarry. In the case of Sungneung, Sureung, and Gyeongneung, the range of susceptibility measurement is widely distributed. It assumed that the newly produced stones were mixed in the moving and construction process. Also, stones might be gathered from different quarries. As a result of a conservation status investigation, both the mound member and the ridge stone had the highest damage rate due to peeling and granular decomposition according to surface weathering. In the case of surface discoloration, yellowing and soils were found in the burial mound members. Yellowing, blackening, and soil were identified in the ridge stone structures. Bio-degradation is the major factor of deterioration of the East Nine Royal Tombs and the conservation status of the tombs were detected as grades 4 to 5. It seems that it is easy for the environment of the royal tombs to form soil for the microorganisms and fine conditions for continuous moisture. In the case of structures, they are in relatively good condition. As a result of a comprehensive damage rating for each tomb, the overall condition is good, but the Geonwolleung Royal Tomb and Hyeolleung Tomb, which were created in the early period, had relatively high weathering ratings. Stone objects in East Nine Royal Tombs have lost many pieces and gateway members due to surface deterioration. Also, secondary damage is ongoing. Each damage factor of the stone artifacts of the East Nine Royal Tombs combines to cause various and continuous damages. Therefore, it is necessary to establish regular conservation status data of the stone artifacts for efficient management after processing as well as conservation treatment of the royal tombs, and specific management manuals and systems. This study investigated the conservation status of stone structures in the East Nine Royal Tombs, a World Heritage Site, and systematically classified them to provide priority and necessity for conservation processing. We look forward to establishing a plan for the conservation and management of the East Nine Royal Tombs with this database in the future.

• Korean Journal of Remote Sensing
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• v.39 no.6_2
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• pp.1651-1669
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• 2023

Sea ice currently covers approximately 7% of the world's ocean area, primarily concentrated in polar and high-altitude regions, subject to seasonal and annual variations. It is very important to analyze the area and type classification of sea ice through time series monitoring because sea ice is formed in various types on a large spatial scale, and oil and gas exploration and other marine activities are rapidly increasing. Currently, research on the type and area of sea ice is being conducted based on high-resolution satellite images and field measurement data, but there is a limit to sea ice monitoring by acquiring field measurement data. High-resolution optical satellite images can visually detect and identify types of sea ice in a wide range and can compensate for gaps in sea ice monitoring using Geostationary Ocean Color Imager-II (GOCI-II), an ocean satellite with short time resolution. This study tried to find out the possibility of utilizing sea ice monitoring by training a rule-based machine learning model based on learning data produced using high-resolution optical satellite images and performing detection on GOCI-II images. Learning materials were extracted from Liaodong Bay in the Bohai Sea from 2021 to 2022, and a Random Forest (RF) model using GOCI-II was constructed to compare qualitative and quantitative with sea ice areas obtained from existing normalized difference snow index (NDSI) based and high-resolution satellite images. Unlike NDSI index-based results, which underestimated the sea ice area, this study detected relatively detailed sea ice areas and confirmed that sea ice can be classified by type, enabling sea ice monitoring. If the accuracy of the detection model is improved through the construction of continuous learning materials and influencing factors on sea ice formation in the future, it is expected that it can be used in the field of sea ice monitoring in high-altitude ocean areas.

• The Journal of Korean Society for Radiation Therapy
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• v.35
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• pp.7-13
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• 2023

Purpose: In this study, we evaluated the effect of using a customized bolus on dose delivery in the treatment plan when cervical cancer protruded out of the body along with the uterus and evaluated reproducibility in patient set-up. Materials & Methods: The treatment plan used the Eclipse Treatment Planning System (Version 15.5.0, Varian, USA) and the treatment machine was VitalBeam (Varian Medical Systems, USA). The radiotherapy technique used 6 MV energy in the AP/PA direction with 3D-CRT. The prescribed dose is 1.8 Gy/fx and the total dose is 50.4 Gy/28 fx. Semiflex TM31010 (PTW, Germany) was used as the ion chamber, and the dose distribution was analyzed and evaluated by comparing the planned and measured dose according to each position movement and the tumor center dose. The first measurement was performed at the center by applying a customized bolus to the phantom, and the measurement was performed while moving in the range of -2 cm to +2 cm in the X, Y, and Z directions from the center assuming a positional error. It was measured at intervals of 0.5 cm, the Y-axis direction was measured up to ±3 cm, and the situation in which Bolus was set-up incorrectly was also measured. The measured doses were compared based on doses corrected to CT Hounsfield Unit (HU) 240 of silicon instead of the phantom's air cavity. Result: The treatment dose distribution was uniform when the customized bolus was used, and there was no significant difference between the prescribed dose and the actual measured value even when positional errors occurred. It was confirmed that the existing sheet-type bolus is difficult to compensate for irregularly shaped tumors protruding outside the body, but customized Bolus is found to be useful in delivering treatment doses uniformly.

• The Korean Journal of Nuclear Medicine Technology
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• v.25 no.1
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• pp.34-40
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• 2021

Purpose If a new test is introduced or reagents are changed in the laboratory of a medical institution, the characteristics of the test should be analyzed according to the procedure and the assessment of reagents should be made. However, several necessary conditions must be met to perform all required comparative evaluations, first enough samples should be prepared for each test, and secondly, various reagents applicable to the comparative evaluations must be supplied. Even if enough comparative evaluations have been done, there is a limit to the fact that the data variation for the new reagent represents the overall patient data variation, The fact puts a burden on the laboratory to the change the reagent. Due to these various difficulties, reagent changes in the laboratory are limited. In order to introduce a competitive bid, the institute conducted a full investigation of Radioimmunoassay(RIA) reagents for each test and established the range of reagents available in the laboratory through comparative evaluations. We wanted to share this process. Materials and Methods There are 20 items of tests conducted in our laboratory except for consignment tests. For each test, RIA reagents that can be used were fully investigated with the reference to external quality control report. and the manuals for each reagent were obtained. Each reagent was checked for the manual to check the test method, Incubation time, sample volume needed for the test. After that, the primary selection was made according to whether it was available in this laboratory. The primary selected reagents were supplied with 2kits based on 100tests, and the data correlation test, sensitivity measurement, recovery rate measurement, and dilution test were conducted. The secondary selection was performed according to the results of the comparative evaluation. The reagents that passed the primary and secondary selections were submitted to the competitive bidding list. In the case of reagent is designated as a singular, we submitted a explanatory statement with the data obtained during the primary and secondary selection processes. Results Excluded from the primary selection was the case where TAT was expected to be delayed at the moment, and it was impossible to apply to our equipment due to the large volume of reagents used during the test. In the primary selection, there were five items which only one reagent was available.(squamous cell carcinoma Ag(SCC Ag), β-human chorionic gonadotropin(β-HCG), vitamin B12, folate, free testosterone), two reagents were available(CA19-9, CA125, CA72-4, ferritin, thyroglobulin antibody(TG Ab), microsomal antibody(Mic Ab), thyroid stimulating hormone-receptor-antibody(TSH-R-Ab), calcitonin), three reagents were available (triiodothyronine(T3), Tree T3, Free T4, TSH, intact parathyroid hormone(intact PTH)) and four reagents were available are carcinoembryonic antigen(CEA), TG. In the secondary selection, there were eight items which only one reagent was available.(ferritin, TG, CA19-9, SCC, β-HCG, vitaminB12, folate, free testosterone), two reagents were available(TG Ab, Mic Ab, TSH-R-Ab, CA125, CA72-4, intact PTH, calcitonin), three reagents were available(T3, Tree T3, Free T4, TSH, CEA). Reasons excluded from the secondary selection were the lack of reagent supply for comparative evaluations, the problems with data reproducibility, and the inability to accept data variations. The most problematic part of comparative evaluations was sample collection. It didn't matter if the number of samples requested was large and the capacity needed for the test was small. It was difficult to collect various concentration samples in the case of a small number of tests(100 cases per month or less), and it was difficult to conduct a recovery rate test in the case of a relatively large volume of samples required for a single test(more than 100 uL). In addition, the lack of dilution solution or standard zero material for sensitivity measurement or dilution tests was one of the problems. Conclusion Comparative evaluation for changing test reagents require appropriate preparation time to collect diverse and sufficient samples. In addition, setting the total sample volume and reagent volume range required for comparative evaluations, depending on the sample volume and reagent volume required for one test, will reduce the burden of sample collection and planning for each comparative evaluation.