• Journal of Korean Tunnelling and Underground Space Association
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• v.23 no.6
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• pp.469-484
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• 2021

Rock mass classification results have a great influence on construction schedule and budget as well as tunnel stability in tunnel design. A total of 3,526 tunnels have been constructed in Korea and the associated techniques in tunnel design and construction have been continuously developed, however, not many studies have been performed on how to assess rock mass quality and grade more accurately. Thus, numerous cases show big differences in the results according to inspectors' experience and judgement. Hence, this study aims to suggest a more reliable rock mass classification (RMR) model using machine learning algorithms, which is surging in availability, through the analyses based on various rock and rock mass information collected from boring investigations. For this, 11 learning parameters (depth, rock type, RQD, electrical resistivity, UCS, V_p, V_s, Young's modulus, unit weight, Poisson's ratio, RMR) from 13 local tunnel cases were selected, 337 learning data sets as well as 60 test data sets were prepared, and 6 machine learning algorithms (DT, SVM, ANN, PCA & ANN, RF, XGBoost) were tested for various hyperparameters for each algorithm. The results show that the mean absolute errors in RMR value from five algorithms except Decision Tree were less than 8 and a Support Vector Machine model is the best model. The applicability of the model, established through this study, was confirmed and this prediction model can be applied for more reliable rock mass classification when additional various data is continuously cumulated.

• Journal of the Korean Applied Science and Technology
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• v.38 no.6
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• pp.1735-1752
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• 2021

In this study, the Bodhi tree powder is used as an additive to Seolgi rice cake and the research is made how useful the additives are to the Seolgi rice cake. This research would be a good way to develop and distribute the Seolgi rice cake which is added with the powder of Bodhi tree. The results of the study are as follows. 1. The water contents of Bodhi tree was 81.64% with 1.75% of crude protein, 0.81% of crude fat, and 0.56% of crude ash. It was found out that the Bodhi tree has higher contents of polypherol and has the efficacy of anti-oxidation property and has the value as the food stuff. 2. When the Seolgi rice cake is made with the addition of Bodhi tree powder, the value of a and b, sugar, hardness, elasticity, texture and viscosity have risen while the contents of water, L value, pH, stickiness and cohesiveness were lowered. The property test showed that the addition of Bodhi tree to Seolgi rick cake would make all testing items "strong" and the addition of 4% of Bodhi tree in the manufacturing of Seolgi rice cake was most preferred. 3. As for the storage of Seolgi rice cake is concerned, as the period of storage goes by, the value a and b, hardness, elasticity and texture and viscosity have increased while the water contents, L value, stickiness and cohesiveness have reduced. As the period of storage gets longer, the total cell number has increased. But as the more volume of Bodhi tree is added to the rice cake, the total cell number has reduced, thus lengthening the storage period. The rest shows that in producing the Seolgi rice cake, the 4% of addition of Bodhi rice cake is deemed to be the best. It was confirmed that the proper volume of Bodhi powder is proper for the Seolgi rice cake and is also good for decorative and quality characteristics for the rice cake.

• Journal of the Korean Orthopaedic Association
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• v.56 no.1
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• pp.51-60
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• 2021

Purpose: Radiocarpal dislocation (RCD), which is caused by high-energy trauma, often involves radial styloid fractures and short radiolunate ligament (SRLL) injuries. Although SRLL injuries may occur as a simple rupture at the attachment site of radius, it may occur with a relatively large avulsed-fragment in the volar rim of the lunate facet of the radius. This study aimed to differentiate the injury type of SRLL and assess the differences in the treatment results depending on the treatment methods that have been applied in RCD with radial styloid fractures. Materials and Methods: Eighteen patients managed surgically with RCD were enrolled in this study. The patients were classified as Group 1 and Group 2 by using the Dumontier method. In this study, Group 2 was subdivided into 2A (purely ligamentous or small avulsion fracture of the volar rim of lunate facet) and 2B (large avulsed-fragment enough to internal fixation) according to the injury type of SRLL. Groups 2A and 2B were treated with direct repair and screw fixation, respectively. Pain, range of motion of the wrist joint, grip strength, and complications on final radiographs were examined. The outcomes were evaluated using patient-rated wrist evaluation (PRWE), and modified Mayo wrist score (MMWS). Results: All patients were Group 2 (six and twelve patients in 2A and 2B, respectively). The mean flexion to extension arch recovered 79%,and the mean grip strength was 72.9% of the uninjured side. Group 2A showed better recovery in extension, flexion and pronation than Group 2B, but there was no difference in radial deviation, ulnar deviation, supination, grip strength and pain. No differences in the PRWE and MMWS were observed between two groups. Complications included traumatic arthritis in seven patients and residual instability in five patients. Conclusion: When the SRLL was injured, the involvement of a large avulsion fracture on the anterior plane of the radiolunate did not affect the test results. On the other hand, it should be observed cautiously because avulsion fractures tend to disturb the joint's reduction through rotation or displacement. In addition, anatomical reduction and sturdy internal fixation are important for restoring the function of the SRLL.

• Journal of the Korean Orthopaedic Association
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• v.56 no.2
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• pp.157-163
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• 2021

Purpose: Xanthomatosis of the Achilles tendons is rare. In some patients, however, the lesions in the Achilles tendon need to be removed, which may be painful and disfiguring. While studies of successful surgical outcomes for the total resection and reconstruction of the Achilles tendon have been reported, reconstruction surgery has a technical challenge, and extended surgical exposures are required. This study analyzed five cases of bilateral xanthoma of the Achilles tendon, which was treated surgically using a wedge-shaped tendon-sparing approach to eliminate the need for tendon reconstruction. Materials and Methods: From July 2010 to May 2018, five patients with xanthomatosis in both Achilles tendons underwent wedge-shaped tendon preserving surgery. The average age was 49 years (range, 40-55 years), and the follow-up period was 21.4 months (range, 12-31 months). The patients consisted of three males and two females. Complications related to surgery were recorded. The outcome measures included the range of motion of the ankle joint, American Orthopaedic Foot and ankle Society (AOFAS) ankle/hindfoot score, and visual analogue scale (VAS) for overall satisfaction at the last follow-up. The availability of a single-limb heel raise and returning time to work were also measured. Results: Wound dehiscence that did not require secondary surgery was noted in one patient. At the last follow-up, the range of motion of the ankle joint was normal in all patients. The mean AOFAS ankle/hindfoot score was 91 (range, 85-96) and the VAS for the overall satisfaction ranged from 8 to 10. The average time between surgery and return to work was 27.6 days (range, 17-58 days) and all patients could perform a single-limb heel raise test. Conclusion: The tendon-sparing technique, which can preserve the anatomical functioning of the Achilles tendon, could be an excellent surgical approach because it has very promising functional and cosmetic surgical outcomes in patients with Achilles tendon xanthomatosis.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.67 no.3
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• pp.180-188
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• 2022

This study was conducted to determine the optimal sowing date for seed yield of summer oat (Avena sativa L.) cultivars "Darkhorse (DH)" and "Highspeed (HS)" in Wanju, Jeonbuk province between 2017 and 2018. We investigated seed yield from 4 sowing dates: July 15, July 30, August 15, and August 30. We evaluated the agronomic characteristics of summer oats (DH and HS). We found the heading date of all cultivars to be within 50 days. Delayed sowing resulted in significantly increased plant height for both years and cultivars. There was no significant difference in spike length of DH and HS which ranged from 12.8 to 17.8 cm. The sowing date of July 30 produced a higher number of grains per spike, but this yield differed significantly by year and cultivars. In 2017, the first sowing resulted in the lowest DH yield at 132 kg per 10a, while the second sowing had the highest yield at 227 kg. HS yield was the lowest in the first sowing at 126 kg and the highest in the third sowing at 219 kg. In 2018, DH had the lowest yield from the first sowing at 184 kg per 10a, and the highest from the second sowing at 240 kg, but there was no significant difference between these yields. The first sowing for HS gave the lowest yield at 160 kg, and the second sowing produced the highest at 258 kg. The germination rate of harvested seeds from each sowing date in 2017 and 2018 was found to be higher than 85% and there was no significant difference between the two cultivars in the 2018 germination rate test. Thus, we found the optimal sowing date for summer cultivation of oats for the highest seed yield to be between July 30 (second sowing) and August 15 (third sowing).

• 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 Culture and Social Issue
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• v.28 no.2
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• pp.187-217
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• 2022

The aim of this study is to examine the psychometric properties of the Korean version of the Post-traumatic Stress Disorder Checklist for DSM-5(PCL-5). For this purpose, online surveys were conducted for two times with a one year interval using the data from 1,077 Korean adults at time 1, and 563 Korean adults at time 2. First, from the result of the confirmatory factor analysis, comparing the model fit of the 1, 4, 6, and 7-factor model, the 4, 6, and 7-factor model showed a acceptable fit, and the best fit was seen in the order of the 7, 6, 4-factor model. Second, the internal consistency, omega coefficient, construct validity, average variance extracted, and test-retest reliability results were all satisfactory.. Third, a correlation analysis with the K-PC-PTSD-5 and the sub-factors of BSI-18 was conducted to check the validity of the Korean Version of PCL-5. As a result, a positive correlation was seen with both K-PC-PTSD-5 and BSI-18. Fourth, a hierarchical multiple regression was performed to examine whether the Korean Version of PCL-5 predicts future PTSD, depression, anxiety, and somatization. As a result, the Korean Version of PCL-5 measured at time 1 significantly predicted PTSD, depression, anxiety, and somatization symptoms at time 2. Fifth, by analyzing the ROC curve, the discriminant power of PCL-5 for screening PTSD symptom groups was confirmed, and the best cut-off score was suggested. As a result of the longitudinal validation of Korean version of PCL-5, it was found that this scale is a reliable and valid measure for Korean adults. By looking into the predictive validity of the scale, it was found that the Korean version of PCL-5 can predict not only PTSD symptoms but also PTSD-related symptoms such as depression, anxiety, and somatization. Also, this study differs from previous validation studies measuring PTSD symptoms in that it suggested a cut-off score to help differentiate PTSD symptom groups.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.68 no.1
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• pp.20-26
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• 2023

Fiber content in the storage roots of sweetpotato varies between different varieties. For examples, the high fiber content of certain types has a poor texture when steamed or roasted. This study was conducted to evaluate the optimal sieve mesh size for separating fibers, the chemical composition of fibers and differences in fiber content among different varieties. We found that the separated fiber content (dry weight) of mashed and steamed sweetpotato was higher after washing three times (143.3 mg/100 g) compared with that washed five times (128.4 mg/100 g). The Hogammi variety remained 85.9% of total fiber content at 10 mesh (2,000 ㎛) and 9.6% of total fiber content at 30 mesh (600 ㎛), and Jinyulmi remained 74.9 and 16.7% of total fiber content , respectively. Therefore, a 30 mesh sieve was considered the most suitable for fiber separation. Among the 10 studied cultivars, Jinhongmi showed the lowest amount of fiber (24.8 mg/100 g) and Hogammi had the highest amount (111.4 mg/100 g), which was 4.5 times larger than that of Jinhongmi. Cellulose, hemicellulose and lignin content of separated fibers showed no difference between the viscous-type Hogammi and powdery-type Jinyulmi varieties, with averages of 32.5, 22.3 and 29.6%, respectively. Correlation results using the Image J program showed a significant correlation between the distribution of the stained area and the fiber content (R = 0.74, p < 0.05). Staining distribution differed among varieties, suggesting that a simple fiber content test could be performed using the staining method on raw sweetpotato. These results provide useful information to help inform farmers on the fiber content of different sweetpotato varieties.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.3
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• pp.264-274
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• 1993

This study was carried out to assess the agronomic characters and physicochemical properties of floury and chalky-endosperm mutant lines induced by chemical mutagen treatment to rice varieties, Hwacheongbyeo and IR24. Linkage analysis of a floury-endosperm gene was carried out using linkage testers. The grain size of brown rice of the mutants was smaller than that of the original varieties. The l, 000-grain and 1$\ell$ weight were lighter in the mutants compared with those in the original varieties. The compound starch granules in the endosperm cell of the mutants showed a loosely-packed crystalline structure. Amylose contents in mutants ranged from 16.9 to 28.5%. Crude protein contents of the mutants were not significantly different from the original rice variety, Hwacheongbyeo, but white core mutant(line 47106) derived from IR24 showed higher protein(l1.32%) compared with IR24(8.30%). The mutants showed slightly harder gel characteristics, and much lower viscosity in Amylograph than original varieties. Steamed rice-cakes from mutant lines showed greater volume than those from original varieties. During the process of alcohol fermentation, Brix in the mutants(especially floury mutants) decreased faster and the alcohol production after 10-day fermentation was much greater in the mutants than in the original varieties. Three different gene loci for floury endosperm characteristics were identified from the allelism test among mutant lines, and the genes were tentatively symbolized as flo-a, flo-b and flo-c, respectively. A floury gene, flo-a, was linked with lg(liguleless) gene in the linkage group N, with R.V. 5.76$\pm$1.72%.

• Microbiology and Biotechnology Letters
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• v.50 no.4
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• pp.548-556
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• 2022

Acylases can have a significant effect on biofilm formation owing to their quorum quenching activity. In this study, we investigated the effects of acylase treatment episodes on multispecies biofilm development. A consortium composed of 9 species belonging to different genera was allowed to form biofilms for 5 days under various treatment episodes (different treatment periods, 1, 2, 3, or 4 days; and two application timings, beginning or later) at 1, 5, 10, 20 and 50 mg·l^-1 acylase concentrations. The acylase treatment for 5 days showed that acylase concentration was negative with biofilm development (linear regression, Y = -0.05·x + 2.37, p < 0.05, R² = 0.88). Acylase was more effective in reducing biofilm formation when it was applied in the beginning (vs. in later development stage) at all acylase concentrations (p < 0.05). ANOVA indicated that treatment period was significant on biofilm formation in both application timings at ≥ 10 mg·l^-1 (p < 0.05). Linearity test results showed that all slope values between period and biofilm were negative in both timings at ≥ 10 mg·l^-1 (p < 0.05, except for the later application at 20 mg·l^-1). When temporal biofilm dynamics were monitored at 20 mg·l^-1, biofilms gradually increased with time at all treatment episodes (p < 0.05), and slope values in linear regression between biofilm and time were lower when acylase was applied in the beginning (p < 0.05). Our findings suggest the importance of the acylase treatment period and application timing on biofilm control.